key: cord-269161-6nsvup68 authors: kapoor, indu; prabhakar, hemanshu; mahajan, charu title: vitamins as adjunctive treatment for coronavirus disease! date: 2020-09-29 journal: ann intensive care doi: 10.1186/s13613-020-00748-7 sha: doc_id: 269161 cord_uid: 6nsvup68 nan we read with great interest the article by li et al., where authors have reviewed many therapeutic strategies for critically ill patients with coronavirus disease (covid-19) [1] . apart from antiviral drugs and anti-bacterial drugs, authors also discussed various adjunctive interventions which included corticosteroids, thymosin alpha a, cyclosporine a, interferons, gamma globulins and many more. they even discussed the chinese medicines which were used in past to treat other viral infections. they also stated that these medicines might benefit covid-19 patients; however, the efficacy and safety of these traditional medicine formulae in covid-19 need to be further confirmed by clinical trials. though authors have not mentioned, another important supplementary adjunct to treat these critically ill patients in intensive care unit is various vitamins. at present times, good immune system is the major weapon against the covid-19 and vitamins help in efficient functioning of immune system. inadequacy of these vitamins in the body can lead to suppressed immunity, which may further predisposes the patient towards infection. these vitamins enhance the three level of immunity in body's defence system by supporting physical barriers (skin/mucosa), cellular immunity and antibody production. vitamins like a, c and e help in enhancing the skin barrier function. vitamins a, b6, b12, c, d and e work synergistically to support the protective activities of the immune cells. all these vitamins except vitamin c are helpful in antibody production. vitamin a has been shown to enhance immune response against influenza virus [2] . a controlled human trial has reported that vitamin c significantly lowers the incidence of pneumonia, suggesting that vitamin c may affect susceptibility to lower respiratory tract infections [3] . kim et al. in their study indicated that combined use of vitamin c, hydrocortisone, and thiamine (vitamin b1) improves the chest radiologic findings of patients with severe pneumonia and reduce their mortality [4] . ilie et al. identified a negative association between the mean vitamin d levels in various european countries with covid-19 cases/1m and covid-19 mortality [5] . the most vulnerable group, the elderly population, is also the amongst the ones who have the most deficient vitamin d levels and are at higher risk for covid-19 infection. a large systematic review and meta-analysis including 11,321 patients has also shown that vitamin d supplementation is effective against acute respiratory tract infection [6] . therefore, these vitamins have shown to protect against the acute viral infections and should be the part of adjunctive therapy in critically ill covid-19 patients. despite the use of vitamins worldwide in covid-19 patients, it is difficult to comment on its absolute therapeutic or preventive role in these group of patients. in future, trials may be needed to understand the role of vitamins in patients of covid-19. therapeutic strategies for critically ill patients with covid-19 baseline serum vitamin a and d levels determine benefit of oral vitamin a&d supplements to humoral immune responses following pediatric influenza vaccination vitamin c intake and susceptibility to pneumonia combined vitamin c, hydrocortisone, and thiamine therapy for patients with severe pneumonia who were admitted to the intensive care unit: propensity score-based analysis of a before-after cohort study the role of vitamin d in the prevention of coronavirus disease 2019 infection and mortality vitamin d supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data ik: this author helped in conceptualization of the manuscript and prepared the first draft. hp: this author helped in finalising the manuscript. cm: this author helped in revising the manuscript. all authors read and approved the final manuscript. none. the authors declare that they have no competing interests.received: 16 june 2020 accepted: 23 september 2020 open access *correspondence: dr.indu.me@gmail.com aiims, new delhi, india key: cord-034441-30pw419v authors: aslan, m. t.; aslan, i̇. ö.; özdemir, öner title: is vitamin d one of the key elements in covid-19 days? date: 2020-06-13 journal: j nutr health aging doi: 10.1007/s12603-020-1517-y sha: doc_id: 34441 cord_uid: 30pw419v nan the epidemic that emerged in recent months and related to severe acute respiratory syndrome coronavirus-2 (sars-cov-2) caused a global threat. when ineffective treatment methods and the lack of vaccines were considered, these issues caused a serious international concern (1). 80% of people who have had covid-19 disease as a result of sars-cov-2 infection have mild illness or no symptoms (asymptomatic). in the rest of population, serious illness can occur. in addition to the clinical picture difference in covid-19 disease, another striking feature is the variability in mortality rates between regions / countries. this difference in clinical table can be attributed to changes in age, comorbidity, race, diet, climate (air temperature / sun exposure), access to healthcare, reporting and surveillance of the population. sars-cov-2, which initially shows its effect as immune suppression, continues its effect with excessive increase in immune system response and results in cytokine storm. afterwards, with the development of acute respiratory distress syndrome (ards) and systemic inflammatory response syndrome (sirs), the covid-19 has far more severe consequences. on the other hand, the antiviral efficacy of vitamin d, which can also be thought as an immunomodulator and anti-inflammatory, has been shown in many studies of recent years (2, 3). here, we will briefly examine the effects of vitamin d on the immune system as well as in the course and prognosis of covid-19 disease under the light of recent literature data. as mentioned in a recent published review (4), where many large studies have been addressed, vitamin d enhances cellular immunity by inducing some antimicrobial peptides, such as some antimicrobial peptides, defensins, e.g. cathelicidine (5-7). catelicidines have a direct antimicrobial effect against gram-positive, gram-negative bacteria, enveloped and nonenveloped viruses and fungi (8) . these peptides kill pathogens by breaking their cell membranes. they can counteract the biological activities of their endotoxins and have many other significant functions like this (9) . vitamin d was shown to reduce influenza a virus replication in a mouse model (10) . in another study, 1,25 (oh)2 d3 has been shown to reduce both in vitro and in vivo replication of rotavirus (11) . in a clinical study, supplementation of 4000 iu / day vitamin d has also been reported to reduce dengue virus infection severity (12) . in addition, vitamin d increases cellular immunity by partially decreasing the cytokine storm caused by the innate immune system. the innate immune system produces both pro-inflammatory and anti-inflammatory cytokines in return to viral and bacterial infections, as seen in covid-19 patients. vitamin d can diminish the production of t helper 1 (th1) cells such as il-2, tnf-α, and interferons. not only vitamin d supplementation decreases the expression of pro-inflammatory cytokines mentioned earlier but also enhances the expression of anti-inflammatory cytokines by monocytes / macrophages (13) . vitamin d deficiency is thought to be a risk element for ards itself as well. in experiments on animals with ards, it has also been shown that virus transmission to the lungs could be reduced by modulating the activity of renin-angiotensin system and ace-2 expression with vitamin d treatment (14) . vitamin d deficiency poses an important health problem in all age groups (15) . quite a few foods contain vitamin d. its main source is the non-enzymatic synthesis of ultraviolet-b (uvb) rays emitted from the sun. with increasing age, the production of vitamin d in the skin and serum 25 (oh) d3 concentrations decrease considerably (16) . this may be one of the key factors for covid-19 disease because case death rates rise with age. the reason may be due to less time exposure to the sun and decreased vitamin d production as a result of low 7-dehydrocholesterol levels in the skin. additionally, medication use also characteristically increases with age. some pharmaceutical medications activate the pregnan-x receptor, reducing serum 25 (oh) d concentrations. these drugs consist of antiepileptics, antineoplastics, antibiotics, anti-inflammatory agents, antihypertensives, antiretrovirals, endocrine drugs, and some herbal medicines. on the other hand, when we look at past pandemics in the world, a strong correlation was found between the case death rates and uvb exposure rates in the influenza epidemic of 1918-1919 (17) . when the mortality rates in the united states (usa) were analyzed, the case mortality rate was approximately 6% in the northern states, whereas in the southern states it decreased to 3.5% (18) . at this point, it comes to our mind that the change in mortality rates may be due to the difference of uvb exposure and vitamin d levels depending on the geographical locations in these regions. in accordance with our opinion, we see that the frequency of vitamin d deficiency is known to be very high in european countries such as italy, spain and france (19) , where the mortality rates due to covid-19 disease are the highest. when another study of 212 patients with proven sars-cov-2 infection was examined, serum 25 (oh) d level was the lowest in clinically severe cases, whereas it was highest in mild cases. relation with serum 25 (oh) d levels was demonstrated to be statistically meaningful among clinical results. when all the results in the study are evaluated, the rise in serum 25 (oh) d levels in the covid-19 patients suggests that it may improve clinical course or alleviate clinical outcomes even in severe cases. on the other hand, it may mean that the decline in serum 25 (oh) d levels in the body may worsen the clinical outcomes in patients (20) . in another study involving twenty european countries, a negative correlation was found between serum 25 (oh) d levels and the total number of cases with covid-19 disease and mortality rates due to this disease (21) . in the light of the literature knowledge above, we know that the antiviral and anti-inflammatory effectiveness of vitamin d is quite high. it comes to mind that vitamin d supplementation in the treatment may have a preventive effect on some negative consequences. among the causes of this clinical diversity in the course and mortality rates of the covid-19 cases, it is an important to remind that vitamin d deficiency can also be underlying comorbidity in the patients. as a conclusion, in this period when we fought against the covid-19 pandemic, which affected many countries around the world and caused thousands of people to die, no clear agent has been found in its treatment. in fact, an easily accessible agent such as vitamin d may be an important weapon in our hands. however, there is no clear evidence for high-dose or dose of vitamin d supplementation in patients with sars-cov-2 infection. although there is a need for more research related to this subject, we think that supplementing vitamin d as a part of standard nutrition may be somewhat effective in providing clinical benefit. the origin, transmission and clinical therapies on coronavirus disease 2019 (covid-19) outbreak -an update on the status the interplay between vitamin d and viral infections association of vitamin d supplementation with respiratory tract infection in infants evidence that vitamin d supplementation could reduce risk of influenza and covid-19 infections and deaths toll-like receptor triggering of a vitamin d-mediated human antimicrobial response vitamin d-directed rheostatic regulation of monocyte antibacterial responses vitamin d and respiratory infection in adults the role of cathelicidin and defensins in pulmonary inflammatory diseases antiviral activity and increased host defense against influenza infection elicited by the human cathelicidin ll-37 vitamin d alleviates rotavirus infection through a microrna-155-5p mediated regulation of the tbk1/ irf3 signaling pathway in vivo and in vitro effect of high doses of vitamin d supplementation on dengue virus replication, toll-like receptor expression, and cytokine profiles on dendritic cells vitamin d and 1,25(oh)2d regulation of t cells vitamin d alleviates lipopolysaccharideinduced acute lung injury via regulation of the reninangiotensin system is vitamin d deficiency a major global health problem aging decreases the capacity of human skin to produce vitamin d3 the possible roles of solar ulraviolet-b radiation and vitamin d in reducing case fatality rates from the 1918-1919 influenza pandemic in the united states does vitamin d status impact mortality from sars-cov-2 infection? current vitamin d status in european and middle east countries and strategies to prevent vitamin d deficiency: a position statement of the european calcified tissue society vitamin d supplementation could possibly improve clinical outcomes of patients infected with coronavirus-2019 (covid-2019). 09.04.2020. pre-print version the role of vitamin d in the prevention of coronavirus disease 2019 infection and mortality. aging clinical and experimental research we would like to thank all our heroes actively working on this subject, both in the field and on the scientific platform, during these challenging days in the world, where the covid-19 pandemic has been experienced. key: cord-298542-4du3gar7 authors: karcioglu batur, lutfiye; hekim, nezih title: the role of dbp gene polymorphisms in the prevalence of new coronavirus disease 2019 infection and mortality rate date: 2020-08-16 journal: j med virol doi: 10.1002/jmv.26409 sha: doc_id: 298542 cord_uid: 4du3gar7 since december 2019, coronavirus disease 2019 (covid‐19), caused by severe acute respiratory syndrome coronavirus 2, has given rise to emerging respiratory infections with pandemic diffusion. the vitamin d binding protein (dbp) with emphasis on its regulation of total and free vitamin d metabolite levels participate in various clinical conditions. the main goal of this study was to evaluate if there was any association between the dbp gene polymorphism at rs7041 and rs4588 loci and the prevalence of covid‐19 and its mortality rates caused among populations of 10 countries including turkey. positive significant correlations were found between the prevalence (per million) and mortality rates (per million), and gt genotype (p < .05) while there was a negative significant correlation between prevalence (per million) and mortality rates (per million), and tt genotype at rs7041 locus among all populations (p < .05). however, no significant correlation was found at rs4588 locus. gt genotype was found to confer this susceptibility to the populations of germany, mexico, italy, czech, and turkey. the variations in the prevalence of covid‐19 and its mortality rates among countries may be explained by vitamin d metabolism differed by the dbp polymorphisms of rs7041 and rs4588. since december 2019, coronavirus disease 2019 , caused by severe acute respiratory syndrome coronavirus 2 (sars-cov-2), has given rise to emerging respiratory infections with a pandemical diffusion. 1 by 2 july 2020, the global number of confirmed cases of covid-19 reached 10 534 765 with a mortality of 512 881. 2 in turkey, 201 098 cases and 5150 deaths have been confirmed until 2nd july 2020. 2 a relationship was recently found between vitamin d levels and the number covid-19 cases and the mortality rates caused by the coronavirus infection. 3 the vitamin d binding protein (dbp) with emphasis on its regulation of total and free vitamin d metabolite levels participate in various clinical conditions. nearly all dbp is produced in the liver, where its regulation is influenced by estrogen, glucocorticoids, and inflammatory cytokines but not by vitamin d itself. dbp is the most polymorphic protein known, and different dbp alleles can have substantial impact on its biologic functions. 4 the two most common alleles-gc1s (rs7041 locus) and gc2 (rs4588 locus)-differ in their affinity with the vitamin d metabolites and have been variably associated with several clinical conditions. 4 among these conditions, g allele at the rs7041 locus was found to be related with increased susceptibility to hepatitis c viral infection. 5 moreover, the individuals having an aa genotype within rs4588 locus of the gc2 polymorphic region showed a greater increase at 25(oh)d levels following vitamin d supplementation than those having the gg genotype. 6 a single-nucleotide polymorphism at rs4588 has been associated with susceptibility to the metabolic syndrome. 7 therefore, we hypothesized that dbp polymorphisms may play a significant role in covid-19. the main goal of this study was to evaluate if there is any association between the dbp gene polymorphism at rs7041 and rs4588 loci and the prevalence of covid-19 and its mortality rates caused among populations of ten countries including turkey. to test this hypothesis and to limit confounding bias (latitude, etc), we focused on the countries whose dbp polymorphisms at rs7041 and rs4588 loci were defined and the allele frequencies reported in five cohort and two systematic review and meta-analysis studies. [8] [9] [10] [11] [12] [13] [14] [15] we searched the literature for dbp gene polymorphism in each country. we recorded the total number of cases of covid-19 and per million population in each of the countries to find the prevalence, and the mortality rates caused by the coronavirus infection recorded at 2nd july 2020 (table 1) coronavirus disease (covid-19) situation report-164. 2 the allele frequencies of dbp polymorphisms at rs7041 and rs4588 loci of turkish population were retrieved from a previous thesis study (unpublished results). 16 the ethical approval for analyzing the blood samples to examine the polymorphisms was obcorrelation between rs7041 and rs4588 polymorphisms and prevalence of covid-19 and mortality rates per country demonstrated that there were positive significant correlations between the prevalence (per million) and mortality rates (per million), and gt genotype (p < .05), while there was a negative significant correlation between prevalence (per million) and mortality rates (per million), and tt genotype at rs7041 locus among all populations (p < .05). however, no significant correlation was found between the prevalence (per million) and mortality rates (per million), and the polymorphism at rs4588 locus (table 2 ). in the present study, tt genotype was found to confer covid-19 susceptibility to the populations of china, japan, nigeria, and kenya. gt genotype was found to confer this susceptibility to the populavitamin d plays a major role in regulating the immune system, including immune responses to viral infection. 24 interventional and observational epidemiological studies provide evidence that vitamin d deficiency may confer an increased risk of influenza and respiratory tract infection. 25 cell culture experiments support the thesis that vitamin d has direct antiviral effects particularly against enveloped viruses. though vitamin d's antiviral mechanism has not been fully established, it may be linked to vitamin d's ability to upregulate the antimicrobial peptides ll-37 and human beta-defensin 2. 26 regarding the genetic susceptibility to a viral infection in vitamin d deficiency, we also observed significant correlations between rs7041 polymorphism and prevalence of covid-19 and mortality rates per country. however, no significant correlation was found between the prevalence (per million) and mortality rates (per million) at rs4588 locus. the pathology of covid-19 involves a complex interaction between the sars-cov-2 and the body immune system. calcitriol (1,25dihydroxyvitamin d3) exerts pronounced impacts on ace2/ang(1-7)/ masr axis with enhanced expression of ace2. 27 ace2 is the host cell receptor responsible for mediating infection by sars-cov-2. ace2 polymorphisms were recently described in human populations. 28 another common polymorphism was found in dbp gene, which is a highly polymorphic gene. allelic variants of the dbp gene have been studied extensively for their association with vitamin d deficiency 29, 30 and viral infections. 5 two of these variants corresponding to different allelic arrangements of rs7041 and rs4588 were reported to have a different clinical characteristics of coronavirus disease 2019 in china world health organization. coronavirus disease (covid-19) situation report-164 the role of vitamin d in the prevention of coronavirus disease 2019 infection and mortality vitamin d binding protein, total and free vitamin d levels in different physiological and pathophysiological conditions vitamin d binding protein polymorphisms influence susceptibility to hepatitis c virus infection in a high-risk chinese population associations of vitamin d binding protein variants with the vitamin d-induced increase in serum 25-hydroxyvitamin d vitamin d-binding protein and its polymorphisms as a predictor for metabolic syndrome gc glu416asp and thr420lys polymorphisms contribute to gastrointestinal cancer susceptibility in a chinese population systematic review and meta-analysis to establish the association of common genetic variations in vitamin d binding protein with chronic obstructive pulmonary disease distribution of variants in multiple vitamin d-related loci association between vitamin d deficiency and common variants of vitamin d binding protein gene among mexican mestizo and indigenous postmenopausal women the associations of 25-hydroxyvitamin d levels, vitamin d binding protein gene polymorphisms, and race with risk of incident fracture-related hospitalization: twenty-year follow-up in a bi-ethnic cohort (the aric study) genetic variation of the vitamin d binding protein affects vitamin d status and response to supplementation in infants the rs1803274 polymorphism of the bche gene is associated with an increased risk of coronary instent restenosis posttraumatic stress disorder is associated with reduced vitamin d levels and functional polymorphisms of the vitamin d binding-protein in a population-based sample the relationship between the genotype of vitamin d binding protein and plasma 25 oh d concentration in turkish population vitamin d-binding protein (rs4588) t/t genotype is associated with anteroseptal myocardial infarction in coronary artery disease patients polymorphisms in the gc gene for vitamin d binding protein and their association with vitamin d and bone mass in young adults vitamin d pathway gene polymorphisms influenced vitamin d level among pregnant women hypovitaminosis d in developing countries-prevalence, risk factors and outcomes scientific strabismus" or two related pandemics: coronavirus disease and vitamin d deficiency prevalence of vitamin d deficiency in otherwise healthy individuals between the ages of 18 and 90 years in southeast turkey adjustments in analyses of vitamin d status, allowing for vitamin d determinants, for covid-19 risks vitamin d and the anti-viral state vitamin d and innate immunity carbohydrate-binding molecules inhibit viral fusion and entry by crosslinking membrane glycoproteins vitamin d receptor activation regulates microglia polarization and oxidative stress in spontaneously hypertensive rats and angiotensin ii-exposed microglial cells: role of renin-angiotensin system ace2 receptor polymorphism: susceptibility to sars-cov-2, hypertension, multi-organ failure, and covid-19 disease outcome the vitamin d axis in the lung: a key role for vitamin d-binding protein vitamin d-binding protein contributes to copd by activation of alveolar macrophages vitamin d deficiency is highly prevalent in copd and correlates with variants in the vitamin d-binding gene vitamin d deficiency update in vitamin d vitamin d-binding protein and vitamin d status of black americans and white americans impaired bone marrow-derived macrophage differentiation in vitamin d deficiency 25-dihydroxyvitamin d3 is a potent suppressor of interferon gamma-mediated macrophage activation sars-cov-2 and covid-19 in older adults: what we may expect regarding pathogenesis, immune responses, and outcomes key: cord-276942-dk1rk908 authors: ebadi, maryam; montano-loza, aldo j. title: perspective: improving vitamin d status in the management of covid-19 date: 2020-05-12 journal: eur j clin nutr doi: 10.1038/s41430-020-0661-0 sha: doc_id: 276942 cord_uid: dk1rk908 nan a novel coronavirus disease 2019 (covid-19) outbreak is a global dramatic pandemic that is immeasurably impacting our communities. considering massive health and economic burden of the covid-19 pandemic, any means by which to improve the condition of patients to accelerate recovery and to reduce the risk of deterioration and death would be considered of significant clinical and economical importance. in patients with covid-19, sars-cov-2 virus binds to angiotensin converting enzyme 2 (ace2) receptors in the respiratory tracts of infected patients to enter host cells [1] . at early stages of the disease, protective immune response is responsible for eliminating virus and, therefore, strategies to improve immune responses are of importance. as disease progresses, lung inflammation and fibrosis occur due to the release of pro-inflammatory cytokines, namely interleukin (il)-1b and il-18 by activated macrophages and type 1 t helper (th1) immune cells [2] . older patients and those that are immunocompromised are at the higher substantial risk [3] . unfortunately, current knowledge gap on human immune response to sars-cov-2 is a critical barrier for treating the disease; however, potential immunomodulators may help alleviate severity and improve outcomes. vitamin d is a secosteroid that has a wide spectrum of immunomodulatory, antiinflammatory antifibrotic, and antioxidant actions. expression of inflammatory cytokine [e.g., il-1α, il-1β, tumor necrosis factor-α] was inhibited by vitamin d and its insufficiency was associated with overexpression of th1 cytokines [4] . we have recently found that severe vitamin d deficiency (<25 nmol/l) is associated with disease progression and increased mortality in patients with autoimmune liver diseases [5] . this attribute has generated interest in vitamin d as a pathogenic factor that can be measured, monitored, and manipulated [6] . patients with common variable immunodeficiency and bronchiectasis [7] as well as older adults [8] who are detected with mild to severe vitamin d deficiency, constitute high risk groups for getting severe illness from covid-19. in addition, vitamin d has an important role in cardiovascular diseases and diabetes mellitus [9] . vitamin d deficiency is also common in obesity [10] and smokers [11] . in chicago, more than half of covid-19 cases and around 70% of covid-19 deaths were observed in african-american individuals [12] who are at the greater risk for vitamin d deficiency [13] . among environmental factors, seasonal variation in sun exposure, geographic latitudes, air pollution, and darker skin influence in vitro vitamin d formation by sunlight [14] . recent investigation of an association between temperature and latitude in the cities affected with covid-19 indicated similarity in temperature and latitude among those highly affected areas [15] . this is an important notion that must be considered as vitamin d concentrations tended to be lower in high-latitude countries [16] . high prevalence of vitamin d deficiency and insufficiency was reported previously for those affected areas (table 1) ; however, it should be acknowledged that divergent included populations may limit the generalizability of the study to other populations. moreover, prevalence of vitamin d deficiency differs among various geographical regions of each country, which limit our ability to simplify the results. epidemiological studies have reported that vitamin d deficiency is associated with viral respiratory tract infections and acute lung injury [17] . vitamin d agonist, calcitriol, exhibited protective effects against acute lung injury by modulating the expression of members of the renin-angiotensin system such as ace2 in lung tissue [18] , supporting the role of vitamin d deficiency as a pathogenic factor in covid-19. vitamin d receptors (vdrs) are extensively distributed in respiratory epithelial cells and immune cells (b cell, t cell, macrophages, and monocytes). 25-hydroxyvitamin d (25ohd), the major circulating form of vitamin d can be converted to the active form (1,25-dihydroxyvitamin d) in the bronchial epithelium and immune cells [19] . the enzyme, 1α-hydroxylase (cyp27b1), required for vitamin d activation, is induced by diverse stimuli, including cytokines and toll-like receptor ligands in the respiratory tract. however, adequate serum levels of 25(oh)d is required to increase levels of 1,25-dihydroxyvitamin d and consequently improve the immune response to respiratory virus infections [20] . type-ii pneumocytes are the primary target of coronaviruses and ace2 receptors are highly expressed on these cells. impaired function of type-ii pneumocytes decrease the surfactant level and increase surface tension in covid-19 [21] . metabolites of 1,25-dihydroxyvitamin d have been reported to stimulate surfactant synthesis in alveolar type-ii cells [22] . in vitro culture of human fetal and adult alveolar type-ii cells with 1,25-dihydroxyvitamin d increased vdr and the expression of surfactantassociated protein b, a lipid-associated protein of the pulmonary surfactant [23] , indicating the potential of vitamin d to reduce surface tension in covid-19. in line with our objective to improve vitamin d status and its associated outcomes in patients with covid-19, studies have shown treatment with high dose of 250,000-500,000 iu vitamin d to be safe in mechanically ventilated, critically ill patients and was associated with decreased hospital length of stay, improved ability of the blood to carry oxygen and increased hemoglobin levels [24, 25] . the risk of acute viral respiratory tract infections was twofold less if the vitamin d serum levels were ≥95 nmol/l (hazard ratio 0.51; 95% ci, 0.25-0.84; p < 0.0001) and the percentage of sick days was five times less (0.80% vs. 3.9%, p = 0.02) compared with the patients with levels <95 nmol/l [26] . to our knowledge, no study to date has measured vitamin d levels and performed high-dose vitamin d treatment in patients with covid-19. high prevalence of vitamin d deficiency in elderly, smokers, patients with chronic diseases, and excess uptake by adipose tissue in obesity make investigations of its role as a therapeutic agent in covid-19 conceivable. accordingly, it should be necessary to measure serum 25(oh)d levels in all inpatient and outpatient populations with covid-19 and in different stages of the disease to identify the importance of maintaining or promptly increasing circulating levels of 25(oh)d into the optimal range of 40-60 ng/ml (100-150 nmol/l) [27] . in this regard, relationship between baseline vitamin d status and disease severity, laboratory biochemical tests of white blood cell count, c-reactive protein, lymphocyte count, lactate dehydrogenase, il-6, platelet count, albumin, and serum ferritin, required hospitalization and intensive care unit admission should be determined. this will help us to identify the ability of low vitamin d levels to risk stratify patients and allow for care to be provided to those who are at increased risk of progression. we acknowledge that the primary stage in treating vitamin d deficiency is to measure a baseline 25(oh)d serum levels and then consider the supplementation dose based on the target level and how rapidly that level must be reached. however, based on previous studies in patients with reparatory disease [28] and in order to quickly and safely increase serum 25(oh)d levels, we recommend patients with low circulating levels (below 50 nmol/l) should be offered vitamin d supplementation of 50,000 iu twice a week at the diagnosis (100,000 iu total). overall, doses [32] 420 patients ≥65 years old admitted to rehabilitation centers deficiency: <50 nmol/l insufficiency: 50-75 nmol/l 94.3% 81.2% united states [33] 26010 adults in the national health and nutrition examination survey 2001-2010 deficiency: <50 nmol/l insufficiency: 50-75 nmol/l 28.9% 41.4% france [34] 297 subjects studied in january and february 2015 deficiency: <50 nmol/l 75.1% united kingdom [35] 278 patients with chronic obstructive pulmonary disease, aged 41-92 years in london deficiency: <50 nmol/l 61.5% above 6000 iu/d are needed to achieve serum 25(oh)d concentrations above 100 nmol/l and intakes of vitamin d up to 15,000 iu/d were found to be safe [29] . association between patients' initial response to vitamin d supplementation with disease progression, recovery, and various clinical outcomes need to be investigated. following 100,000 iu start dose, we propose patients to continue with the dose of 50,000 iu taken once a week for the second and third weeks. following doses of 50,000 iu is suggested to achieve optimal levels of 25(oh)d in patients with poor baseline vitamin d status. supplemented patients should be monitored to ensure their circulating vitamin levels are normalized and sustained for the duration of the covid-19 pandemic. this suggested plan presents important challenges to identify how disease features and progression, hospital admission and length of stay, duration of mechanical ventilation, hospital mortality, and respiratory failure differ between the early responder and nonresponder groups. due to the lack of data, symptomatic management is used for covid-19 infection including oxygen therapy and mechanical ventilation for those with severe infection. considering the range of beneficial effects ascribed to vitamin d, it is safety and ease of administration, as well as direct effects of vitamin d on immune cell proliferation and activity, pulmonary ace2 expression and reducing surface tension, evaluation of vitamin d supplementation as an adjuvant therapeutic intervention could be of substantial clinical and economic significance. empiric intervention with vitamin d is a clinical decision that can be justified by low serum levels and the risk of impaired immune system. importantly, improvement in circulating 25(oh)d levels opens possibilities for slowing disease progression or even improving survival of patients. in summary, given the high prevalence of vitamin d deficiency and in order to rapidly, safely, and significantly raise serum concentrations, high-dose vitamin d intervention with potential benefit in decreasing risk of covid-19 severity and mortality is suggested, which is a safe and noninvasive treatment. patients would take large doses of vitamin d for a week, followed by several thousand iu/d vitamin d for a period of 2 weeks. this will provide a quick and sustainable restoration of serum vitamin d levels, thus, potentially triggering an improvement in clinical status and prognosis. however, prospective clinical studies are required to address this speculation and overcome the obstacles in our current understanding of vitamin d role as an adjuvant therapy in patients with covid-19. conflict of interest the authors declare that they have no conflict of interest. publisher's note springer nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. sars-cov-2 cell entry depends on ace2 and tmprss2 and is blocked by a clinically proven protease inhibitor induction of pro-inflammatory cytokines (il-1 and il-6) and lung inflammation by coronavirus-19 (covi-19 or sars-cov-2): anti-inflammatory strategies di napoli r. features, evaluation and treatment coronavirus (covid-19) vitamin d and respiratory health severe vitamin d deficiency is a prognostic biomarker in autoimmune hepatitis evolving role of vitamin d in immune-mediated disease and its implications in autoimmune hepatitis vitamin d deficiency in patients with common variable immunodeficiency, with autoimmune diseases and bronchiectasis the role 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and clinical features of covid-19 25-dihydroxy-3-epi-vitamin d3, a natural metabolite of 1alpha,25-dihydroxy vitamin d3: production and biological activity studies in pulmonary alveolar type ii cells regulation of human pulmonary surfactant protein gene expression by 1alpha,25-dihydroxyvitamin d3 high dose vitamin d administration in ventilated intensive care unit patients: a pilot double blind randomized controlled trial high-dose vitamin d3 administration is associated with increases in hemoglobin concentrations in mechanically ventilated critically ill adults: a pilot double-blind, randomized, placebo-controlled trial serum 25-hydroxyvitamin d and the incidence of acute viral respiratory tract infections in healthy adults the importance of body weight for the dose response relationship of oral vitamin d supplementation and serum 25-hydroxyvitamin d in healthy volunteers influence of a single oral dose of vitamin d (2) on serum 25-hydroxyvitamin d concentrations in tuberculosis patients evaluation of vitamin d3 intakes up to 15,000 international units/day and serum 25-hydroxyvitamin d concentrations up to 300 nmol/l on calcium metabolism in a community setting vitamin d deficiency as a potential marker of benign prostatic hyperplasia high prevalence of vitamin d deficiency among iranian population: a systematic review and meta-analysis 25(oh) vitamin d and functional outcomes in older adults admitted to rehabilitation units: the safari study vitamin d deficiency and insufficiency among us adults: prevalence, predictors and clinical implications prevalence and risk factors of vitamin d deficiency in healthy adults aged 18-65 years in northern france prevalence, determinants and clinical correlates of vitamin d deficiency in patients with chronic obstructive pulmonary disease in london key: cord-257595-l8bsoqbx authors: whittemore, paul b. title: covid-19 fatalities, latitude, sunlight, and vitamin d date: 2020-06-26 journal: am j infect control doi: 10.1016/j.ajic.2020.06.193 sha: doc_id: 257595 cord_uid: l8bsoqbx background: since vitamin d is known to be vital in regulating the immune system, and sunlight uv radiation exposure on the skin produces vitamin d and uv intensity is highest nearest the equator, a study was done to examine the correlation between the latitude and covid-19 fatality rates for countries. methods: eighty-eight countries were selected based on their likelihood of providing reliable data. using death rates/million for each country from the “worldometer” web site, a correlation analysis was done between death rates and a country's latitude. results: a highly significant, positive correlation was found between lower death rates and a country's proximity to the equator (pearson r = .40 p<.0001, two-tailed t-test). the r squared of .16 means that 16% of the variation in death rates among nations is accounted for by the latitude of the country. evidence is presented suggesting a direct correlation between sunlight exposure and reduced mortality. discussion: this study is the first to document a statistically significant correlation between a country's latitude and its covid-19 mortality and is consistent with other research regarding latitude, vitamin d deficiency, and covid-19 fatalities. limitations of this study are noted. conclusion: further research is needed to confirm the correlation between latitude and covid-19 fatalities, and to determine the optimum amounts of safe sunlight exposure and/or vitamin d oral supplementation to reduce covid-19 fatalities in populations that are at high risk for vitamin d deficiency. this study is the first to document a statistically significant correlation between a country's latitude and its covid-19 mortality and is consistent with other research regarding latitude, vitamin d deficiency, and covid-19 fatalities. limitations of this study are noted. conclusion: further research is needed to confirm the correlation between latitude and covid-19 fatalities, and to determine the optimum amounts of safe sunlight exposure and/or vitamin d oral supplementation to reduce covid-19 fatalities in populations that are at high risk for vitamin d deficiency. as the covid-19 pandemic spread, death rates reported for over 200 countries and territories on the "worldometer" website appeared to be higher in countries farther from the equator compared with those closer to the equator [1] . a striking example of this appeared in the may 11, 2020 data between ireland and singapore, whose population size was similar (4.9 million vs. 5.3 million respectively), total number of cases were similar (23,135 vs. 23,822 respectively), and number of cases per million of their population was similar (4,685/million vs 4,072/million respectively). however, the number of deaths in ireland was 297/million compared with 4/million in singapore [1] . despite similar numbers of cases, ireland had 74 times more fatalities than singapore. by the second week of may, 2020 several medical studies appeared describing significant correlations between vitamin d insufficiency, covid-19 mortality rates, and the suspected pathophysiology of covid-19 deaths [2] [3] [4] [5] [6] . without adequate vitamin d levels, the lungs are vulnerable to fatal immune system dysregulation including but not limited to cytokine storms, insufficient protection from epithelial cell apoptosis, and deficient epithelial cell repair [4, 6] . because direct sunlight on the skin produces vitamin d in the human body, it has been hypothesized that populations with more regular exposure to natural uv radiation from the sun might have less vitamin d deficiency than those with less uv exposure and consequently lower fatality rates from covid-19 [5] . while uv exposure from sunlight is affected by many factors such as clouds, weather, and pollution, a country's proximity to the equator also affects uv exposure because the intensity of uv radiation is higher closer to the equator. the present study was undertaken to examine the correlation between proximity to the equator and death rates from covid-19. because of the positive correlation between sunlight uv radiation and healthy vitamin d levels in the body, and reported positive correlation between vitamin d deficiency and fatality rates to covid-19, the present study examined the relationship between a country's proximity to the equator and its death rates from the current pandemic. this study hypothesized that countries closer to the equator would have lower fatality rates from covid-19 than countries farther away. to test this hypothesis, a correlation analysis was done comparing a country's latitude and its covid-19 identified death rates per million members of the country's population. to improve the accuracy of reported death between countries, the present study sought to include only countries whose governments have a favorable history of transparency. "transparency international" ranks a total of 180 countries listed from most to least transparent based on multiple measures of government transparency [7] . only the 90 countries in the top 50% were selected for inclusion in this study. latitude data were provided by csgnetwork.com [8] using each country's capital, with exceptions made for china and italy whose vast majority of cases were concentrated in latitudes different from their capitals. wuhan's latitude was used instead of beijing for china, and milan's was used instead of rome for italy. death rates per million in the population for each country was taken from the "worldometer" website on may 17, 2020 [1] . all but 2 of the chosen 90 countries and territories (vanuatu and solomon islands) had data on the worldometer, leaving an n = 88 used for the analysis. the deaths per million/population and latitude for each of the 88 countries were independently entered twice on separate occasions and compared to insure accuracy. a pearson r correlation computation was done on both data sets on google sheets "correlation" and compared for accuracy and consistency [9] . the pearson product-moment correlation on both data sets obtained a correlation coefficient of r = .40. the probability for this outcome was statistically calculated and was found to be extremely low, p<.00005 for one-tailed probability using the hypothesis of lower mortality in populations closer to the equator. the probability of this outcome occurring with no predicted direction was still very low, at p<.0001 for two-tailed probability [10]. the r = .40 translates to a coefficient of determination (r squared) = .16; i.e. 16% of the variance in mortality rates is attributed to the country's latitude. such a high correlation for such a crude factor as latitude is surprising yet credible considering other research showing significant correlations between sunlight exposure and cancers. lower risks for cancer have been found in countries with higher levels of sunlight exposure [11] [12] [13] . one study compared cancers in sunny countries with lower latitudes with less sunny countries with higher latitudes and concluded "that vitamin d production in the skin decreased the risk of several solid cancers (especially stomach, colorectal, liver and gallbladder, pancreas, lung, female breast, prostate, bladder and kidney cancers)" [13] . significantly lower rates of prostate cancer was found in men whose birth place and longest place of residence was in southern states of the us, leading the authors to conclude that "residential sunlight exposure reduces the risk of prostate cancer" [14] . deaths from prostate cancer in america were compared with sunlight uvb exposure and the results were highly significant (r = -.0001), meaning that men who received more sunlight were less likely to die from prostate cancer [12] . the present study finding a strong correlation between latitude and covid-19 fatalities may be explained by the role of sunlight on the skin producing vitamin d [5] , and the research linking vitamin d deficiency and covid-19 fatalities [2] [3] [4] [5] [6] . while the present study does not address vitamin d directly, its production in the human body due to uv sunlight exposure, and the known increase of uv radiation intensity closer to the equator lead to the likelihood that populations closer to the equator have more adequate endogenous vitamin d compared with populations farther away, thereby reducing the likelihood of a fatal dysfunction of the immune system in the presence of covid-19 [11] . the relevance of sunlight exposure for covid-19 is illustrated by comparing statistics involving milan and naples, italy. it is claimed that little or no sunlight uv radiation reaches the earth during winter months in countries whose latitude is above 40 degrees [5] . milan's latitude is significantly above 40 degrees (45.46n) and its covid-19 epidemic accelerated rapidly in the winter month of february , which is nearly two more months of sunshine each year for its population. this comparison supports the hypothesis that the underlying mechanism behind the latitude-mortality correlation is due to differences in sunlight uv radiation and the subsequent levels of endogenous vitamin d in the respective populations. limited sunlight exposure for those in institutional settings, such as prisons and skilled nursing facilities, has been suggested as the reason that 75% of these populations are vitamin d deficient and suffer disproportionately high levels of covid-19 mortality [2] . lower vitamin d levels also are associated with advanced age [18] , diabetes [19] , and hypertension [20] , three of the same risk factors associated with covid-19 fatalities and also common in nursing home populations. even if patients in nursing homes are ingesting adequate amounts of vitamin d in their diet, that may not be sufficient since some studies finds dietary vitamin d less effective than that produced by exposure to sunlight [14] . the current study is the first to document a statistically significant correlation between a country's latitude and its covid-19 mortality. the highly significant probability (p<.0005) that countries proximal to the equator have lower covid-19 fatalities than distal countries supports a probable connection between latitude, sunlight exposure, vitamin d, and covid-19 fatality. the most probable explanation for the correlation found between latitude and covid-19 deaths is the mechanism of vitamin d induced by sunlight exposure [5] . further research is needed to see if endogenous vitamin d is protective against covid-19, and if so, what the optimal amount of safe sunlight exposure is to produce a protective effect. it is important to note that sunlight exposure does not bestow uniform benefits to all members of the population. the effectiveness by which uv radiation on the skin produces endogenous vitamin d is modified by the age, skin color, and sex of the person [3, 5] . the body's efficiency in producing vitamin d from sunlight decreases with age, such that elderly women in ecuador where sunlight is abundant have been found deficient in vitamin d [5] . darker skin color reduces the production of vitamin d from uv exposure, and this may be one of the reasons that african americans suffer twice the prevalence of vitamin d insufficiency compared with the general population (82.1% vs 41.6%) and disproportionately high mortality rates from covid-19 [3] . in addition to skin color and aging, local customs may also impact the results of uv exposure in the population: vitamin d deficiency has been found in girls and women in the middle east despite plenty of sunlight [5] . an important limitation in this study is the unknown duration of time between the identification of first cases in a country and the reported death rates. all other factors being equal, death rates in a country where cases began to appear recently will appear lower than those in countries fighting the virus for a longer time. such variability could raise or lower the numbers used in a correlation study depending on the country's latitude. that does not appear to have changed the striking difference between the death rates in ireland and singapore mentioned in the introduction. on may 11, 2020 the "worldometer" ireland appears to have slowed the rate of increased cases compared with singapore, it now has a fatality rate that is 86 times higher than singapore's. this paired comparison is not only consistent with a positive correlation between equatorial proximity and low fatality rates, it also shows that the difference in the reported death rates for this pair of countries is not the result of different time durations from diagnosis to mortality. the above comparison may be an anomaly, and the fact remains that the unknown duration of time in our 88 countries from first identified cases to reported deaths represents a potential confound to these results. statistical probability testing cannot eliminate this confounder, but may reduce the likelihood of falsely claiming a significant correlation. the more extreme the "p" value is, the lower the likelihood is of erroneously finding a correlation that is not there (i.e. of making a "type 1 error" in statistical hypothesis testing.) the results of this study support that of other research that points to the urgent need to correct vitamin d deficiency to reduce covid-19 fatalities [2] [3] [4] [5] [6] 14] . further research regarding the amounts of safe sunlight exposure and of vitamin d oral supplementation is indicated because, even if they are only partially effective, they are cheap, safe, and readily available. finding such ways for the general public to fortify the immune system (while scientists continue searching for medical treatments and a vaccine) would be a welcome and overdue addition of "inner" strategies in fighting covid-19 to the "outer" ones (social distance, masks, disinfecting surfaces) that have been receiving exclusive attention. worldometer covid-19 coronavirus pandemic the role of vitamin d in the prevention of infection and mortality vitamin d insufficiency is prevalent in severe covid-19 the possible role of vitamin d in suppressing cytokine storm and associated mortality in covid-19 patients does vitamin d status impact mortality from sars-cov-2 infection? med drug discov vitamin d attenuates lung injury via stimulating epithelial repair, reducing epithelial cell apoptosis and inhibits tgf-β induced epithelial to mesenchymal transition corruption perceptions index pearson r computation with "correlation vitamin d and prostate cancer risk: a review of the epidemiological literature geographic patterns of prostate cancer mortality. evidence for a protective effect of ultraviolet radiation does solar exposure, as indicated by the non-melanoma skin cancers, protect from solid cancers: vitamin d as a possible explanation residential sunlight exposure is associated with a decreased risk of prostate cancer annual sunshine and daylight hours in milan differences in vitamin d status between countries in young adults and the elderly the prevalence of hypovitaminosis d and secondary hyperparathyroidism in obese black americans evidence for alteration of the vitamin d-endocrine system in obese subjects the author would like to thank the anonymous reviewers for their informed and valuable suggestions for improving the manuscript. thanks also go to jane l.whittemore and rolly d. spradling, ph.d. for their support and assistance during research and preparation of the manuscript. key: cord-324246-liyk6mna authors: shakoor, hira; feehan, jack; mikkelsen, kathleen; al dhaheri, ayesha s.; ali, habiba i.; platat, carine; ismail, leila cheikh; stojanovska, lily; apostolopoulos, vasso title: be well: a potential role for vitamin b in covid-19 date: 2020-08-15 journal: maturitas doi: 10.1016/j.maturitas.2020.08.007 sha: doc_id: 324246 cord_uid: liyk6mna nan coronavirus disease is caused by the sars-cov-2 virus. in january 2020, the world health organization declared covid-19 as a public health emergency of international concern and in march 2020, covid-19 was characterized as a global pandemic that is responsible for infecting over 20 million and more than 700,000 deaths. covid-19 symptoms are fever, cough, fatigue, headache, diarrhea, arthromyalgias, serious interstitial pneumonia that can lead to acute respiratory distress syndrome, sepsis-induced coagulopathy and multi-organ dysfunction [1] . in addition, the severe progression of covid-19 results in cytokine storm with excessive production of pro-inflammatory cytokines [2] . previously, outbreaks of similar viruses which belong to the β-coronavirus family occurred in [2002] [2003] [2004] and 2012-2014, as severe acute respiratory syndrome (sars) and as the middle east respiratory syndrome (mers), respectively [3, 4] . currently, there is no approved drug treatment or vaccine against the sars-cov-2 virus. until these become available, one must include adequate and balanced nutrition for proper body functioning and boosting of the immune system. micronutrients, vitamin c and vitamin d have gained much attention during the pandemic because of their anti-inflammatory and immune-supporting properties. low levels of vitamins d and c result in coagulopathy and suppress the immune system, causing lymphocytopenia. evidence has shown that the mortality rate is higher in covid-19 patients with low vitamin d concentrations. further, vitamin c supplementation increases the oxygenation index in covid-19 infected patients [5] . similarly, vitamin b deficiency can significantly impair cell and immune system function, and lead to inflammation due to hyperhomocysteinemia. there is a need to highlight the importance of vitamin b because it plays a pivotal role in cell functioning, energy metabolism, and proper immune function [6] . vitamin b assists in proper activation of both the innate and adaptive immune responses, reduces pro-inflammatory cytokine levels, improves respiratory function, maintains endothelial integrity, prevents hypercoagulability and can reduce the length of stay in hospital [7, 8] . therefore, vitamin b status should be assessed in covid-19 patients and vitamin b could be used as a non-pharmaceutical adjunct to current treatments ( figure 1 ). thiamine is able to improve immune system function and has been shown to reduce the risk of type-2 diabetes, cardiovascular disease, aging-related disorders, kidney disease, cancer, mental disorders and neurodegenerative disorders [6] . thiamine deficiency affects the cardiovascular system, causes neuroinflammation, increases inflammation and leads to aberrant antibody responses [6] . as antibodies, and importantly t-cells, are required to eliminate the sars-cov-2 virus, thiamine deficiency can potentially result in inadequate antibody responses, and subsequently more severe symptoms. hence, adequate thiamine levels are likely to aid in the proper immune responses during sars-cov-2 infection. in addition, the symptoms of covid-19 are very similar to altitude sickness and high-altitude pulmonary edema. acetazolamide is commonly prescribed to prevent high-altitude sickness and pulmonary edema through inhibition of the carbonic anhydrase isoenzymes and subsequently increases oxygen levels. thiamine also functions as a carbonic anhydrase isoenzyme inhibitor [9] ; hence, high-doses of thiamine given to people at early stages of covid-19 could potentially limit hypoxia and decrease hospitalization. further research is required to determine whether administration of high thiamine doses could contribute to the treatment of patients with covid-19. riboflavin together with uv light cause irreversible damage to nucleic acids such as dna and rna, rendering microbial pathogens unable to replicate. riboflavin and uv light has been shown to be effective against the mers-cov virus, suggesting that it could also be helpful against sars-cov-2 [10] . in fact, riboflavin-uv decreased the infectious titer of sars-cov-2 below the limit of detection in human blood [10] and in plasma and platelet products [11] . this could alleviate some of the risk of transfusion transmission of covid-19 and as well as reducing other pathogens in blood products for critically ill covid-19 patients. niacin acts as a building block of nad and nadp, both vital during chronic systemic inflammation [12] . nad + acts as a coenzyme in various metabolic pathways and its increased levels are essential to treat a wide range of pathophysiological conditions. nad + is released during the early stages of inflammation and has immunomodulatory properties, known to decrease the pro-inflammatory cytokines, il-1β, il-6 and tnf-α. [13] [14] [15] . recent evidence indicates that targeting il-6 could help control the inflammatory storm in patients with covid-19 [16] . moreover, niacin reduces neutrophil infiltration and exhibits an anti-inflammatory effect in patients with ventilator-induced lung injury. in hamsters, niacin and nicotinamide prevents lung tissue damage [17] . in addition, nicotinamide reduces viral replication (vaccinia virus, human immunodeficiency virus, enteroviruses, hepatitis b virus) and strengthens the body's defense mechanisms. taking into account the lung protective and immune strengthening roles of niacin, it could be used as an adjunct treatment for covid-19 patients [8, 18] . pantothenic acid has a number of functions, including cholesterol-and triglyceride-lowering properties, improves wound healing, decreases inflammation and improves mental health [6] . even though there are limited studies demonstrating the effects of pantothenic acid on the immune system, it is a viable vitamin for future investigation. pyridoxal 5'-phosphate (plp) is an active form of pyridoxine, and is an essential cofactor in various inflammatory pathways with deficiency leading to immune dysregulation. plp has an inverse relationship with plasma il-6 and tnf-α in chronic inflammatory conditions. during inflammation, the utilization of plp increases results in its depletion, suggesting that covid-19 patients with high inflammation may have deficiency. low plp levels have been noted in patients with type-2 diabetes, cardiovascular disease and in the elderly [19] [20] [21] , groups who are at higher risk of poorer covid-19 outcomes. dysregulation of immune responses and increased risk of coagulopathy have also been noted among covid-19 patients. in a recent preprint it is suggested that plp supplementation mitigates covid-19 symptoms by regulating immune responses, decreasing pro-inflammatory cytokines, maintaining endothelial integrity and preventing hypercoagulability [22] . in fact, it was shown three decades ago that plp levels reduce abnormalities in platelet aggregation and blood clot formation [23] . recently researchers at victoria university reported that vitamin b6 (as well as b2 and b9) upregulated il-10, a powerful anti-inflammatory and immunosuppressive cytokine which can deactivate macrophages and monocytes and inhibit antigenpresenting cells and t cells [24] . covid-19 patients often respond to the virus by mounting an excessive t cell response and secretion of pro-inflammatory cytokines. it may be that plp is able to contribute to dampening the cytokine storm and inflammation suffered by some covid-19 patients. folate is an essential vitamin for dna and protein synthesis and in the adaptive immune response. furin is an enzyme associated with bacterial and viral infections and is a promising target for treatment of infections. recently, it was noted that folic acid was able to inhibit furin, preventing binding by the sars-cov-2 spike protein, preventing cell entry and virus turnover. therefore it was suggested that folic acid could be beneficial for the management of covid-19-associated respiratory disease in the early stages [25] . a recent preprint report that folic acid and its derivatives tetrahydrofolic acid and 5-methyl tetrahydrofolic acid have strong and stable binding affinities against the sars-cov-2, through structurebased molecular docking. therefore, folic acid may be used as a therapeutic approach for the management of covid-19 [26] . vitamin b12 is essential for red blood cell synthesis, nervous system health, myelin synthesis, cellular growth and the rapid synthesis of dna. the active forms of vitamin b12 are hydroxo-, adenosyl-and methyl-cobalamin. vitamin b12 acts as a modulator of gut microbiota and low levels of b12 elevate methylmalonic acid and homocysteine, resulting in increased inflammation, reactive oxygen species and oxidative stress [15] . hyperhomocysteinemia causes endothelial dysfunction, activation of platelet and coagulation cascades, megaloblastic anemia, disruption of myelin sheath integrity and decreased immune responses [27] [28] [29] [30] . however, sars-cov-2 could interfere with vitamin b12 metabolism, thus impairing intestinal microbial proliferation. given that, it is plausible that symptoms of vitamin b12 deficiency are close to covid-19 infection such as elevated oxidative stress and lactate dehydrogenase, hyperhomocysteinemia, coagulation cascade activation, vasoconstriction and renal and pulmonary vasculopathy [28, 31] . in addition, b12 deficiency can result in disorders of the respiratory, gastrointestinal and central nervous systems [30] . surprisingly, a recent study showed that methylcobalamin supplements have the potential to reduce covid-19-related organ damage and symptoms [32] . a clinical study conducted in singapore showed that covid-19 patients who were given vitamin b12 supplements (500 µg), vitamin d (1000 iu) and magnesium had reduced covid-19 symptom severity and supplements significantly reduced the need for oxygen and intensive care support [33] . j o u r n a l p r e -p r o o f vitamin b not only helps to build and maintain a healthy immune system but it could potentially prevent or reduce covid-19 symptoms or treat sars-cov-2 infection. poor nutritional status predisposes people to infections more easily; therefore, a balanced diet is necessary for immuno-competence. there is a need for safe and cost-effective adjunct or therapeutic approaches, to suppress aberrant immune activation, which can lead to a cytokine storm, and to act as anti-thrombotic agents. adequate vitamin intake is necessary for proper body function and strengthening of the immune system. in particular, vitamin b modulates immune response by downregulating pro-inflammatory cytokines and inflammation, reducing breathing difficulty and gastrointestinal problems, preventing hypercoagulability, potentially improving outcomes and reducing the length of stay in the hospital for covid-19 patients. hira shakoor contributed to the writing and revision of this editorial. jack feehan contributed to the revision of this editorial. kathleen mikkelsen contributed to the revision of this editorial. ayesha s al dhaheri contributed to the revision of this editorial. habiba i ali contributed to the revision of this editorial. carine platat contributed to the revision of this editorial. leila cheikh ismail contributed to the revision of this editorial. lily stojanovska contributed to the revision of this editorial. vasso apostolopoulos conceptualized the editorial and contributed to the writing, revision and approval of the final version of this editorial. coronavirus disease 2019 (covid-19): a perspective from china the cytokine release syndrome (crs) of severe covid-19 and interleukin-6 receptor (il-6r) antagonist tocilizumab may be the key to reduce the mortality middle east respiratory syndrome coronavirus envelope protein: current knowledge immune 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deficiency and metabolism-mediated thrombotic microangiopathy (mm-tma) sars-cov-2: micronutrient optimization in supporting host immunocompetence the many faces of cobalamin (vitamin b12) deficiency adult-onset renal thrombotic microangiopathy and pulmonary arterial hypertension in cobalamin c deficiency can vitamin b12 be an adjuvant to covid-19 treatment? a cohort study to evaluate the effect of combination vitamin d, magnesium and vitamin b12 (dmb) on progression to severe outcome va would like to thank the immunology and translational research group and the institute for health and sport, victoria university for their support. km was supported by the victoria university postgraduate scholarship and the vice chancellors top up scholarship. jf was supported by the university of melbourne postgraduate scholarship. hs, ad, ha, cp ls would like to acknowledge the department of food, nutrition and health, united arab emirates university, and li would like to acknowledge the clinical nutrition and dietetics department, university of sharjah for their ongoing support. the authors declare that they have no conflict of interest. no funding was received for the preparation of this editorial. this article was commissioned and was not externally peer reviewed. key: cord-329321-usqjkj89 authors: chakhtoura, m.; napoli, n.; fuleihan, g. el hajj title: myths and facts on vitamin d amidst the covid-19 pandemic() date: 2020-05-26 journal: metabolism doi: 10.1016/j.metabol.2020.154276 sha: doc_id: 329321 cord_uid: usqjkj89 nan covid-sars-2 pandemic has struck and spread at light speed, reaching 6 continents within 3 months, transforming our societies globally [1] . in less than 6 months numbers rose exponentially to 5,159,674 cases and 335,4186 fatalities (6.5%); a third roughly are in the us (may 22, 2020) [2] . disease severity and mortality rates are higher in the elderly, african americans, patients with diabetes mellitus, chronic lung and cardiovascular diseases [3, 4] , all groups with low vitamin d levels. should we supplement patients with vitamin d? we examine the biological plausibility and evidence for a role of vitamin d in covid-19 patients, and provide a framework for guidance on supplementation, based on a rigorous and systematic approach. we interrogated the systematic reviews database epistemonikos, and four medical databases including cochrane. the beneficial role of the sunshine vitamin on musculoskeletal health is undisputed. vitamin d insufficiency, a serum 25-hydroxy vitamin d [25(oh)d] between 20-50 nmol/l (8-20 ng/ml), causes calcium malabsorption, secondary hyperparathyroidism, accelerated bone loss, osteoporosis and fractures in adults [5] . deficiency, a serum 25(oh)d < 20 nmol/l, decreases the serum calcium-phosphate product, and leads to rickets in children and osteomalacia in adults [5] . both can be prevented with daily supplements of 400-800iu of vitamin d, provided calcium intake is adequate. in elderly or institutionalized subjects, vitamin d at doses of 800-2,000 iu/day, co-administered with calcium, reduces the risk of hip fractures by 15-30%, and of other non-vertebral fractures by 20% [5] [6] [7] . these doses are within ranges recommended by major organizations pre-covid times. ecological studies suggest that high latitudes (>+30ºn), and winter season, risk factors for low vitamin d, are associated with higher mortality rates in covid-19 infections [8] [9] . several exceptions exist and are likely explained by other contributing factors such as population age, density and ethnicity, lifestyle factors, and social distancing measures [10] . obesity is a risk factor to all non-communicable diseases, and an increasing number of reports identify obesity as a risk factor for covid-19 related morbidity and mortality [11] [12] . however, although bmi is a known predictor of vitamin d status [13] [14] [15] , hypovitaminosis d in this population may be explained by poor lifestyle habits, vitamin d sequestration in adipose tissue, and altered metabolism [16] . retrospective case-control studies reveal inverse associations between serum 25(oh)d level and the risk of covid -19 infection or severity. they all suffer from major limitations [17] [18] [19] [20] . two are non-peer-reviewed papers [17, 20] . in the case of uk biobank studies samples were collected in 2006-2010 [17, 18] , while studies from switzerland and belgium did not characterize controls, nor adjusted for other predictors [19, 20] . clear support for causality between serum 25(oh)d levels and covid-19 therefore remains elusive. hypovitaminosis d increases the risk for viral respiratory infections [21] . the most feared complications, in a report of over 46,000 covid-19 patients, were bilateral pneumonias (76%), acute respiratory distress syndrome (ards) with icu admissions (29%), and multi-organ failure (8.5%) [22] . of the viral infection [23] . sars-cov-2, infects respiratory epithelial cells through the ace2 receptor, triggers pyroptosis, the release of pro-inflammatory cytokines such as il6, and chemokines. these attract monocytes, macrophages, and t cells, the latter producing ifnγ further contributing to inflammation. in an immune-compromised host, this progresses to the cytokine storm, which coupled with the production of non-neutralizing antibodies by b cells, leads to further organ damage [23] . vitamin d modulates innate and adaptive immunity, through the vitamin d receptor (vdr) and cyp27b1, the enzyme converting it to the active metabolite calcitriol, both of which are expressed in immune cells [23] [24] [25] . the effect of vitamin d on immunity and viral respiratory diseases has been tested. vitamin d metabolites do not consistently influence replication or clearance of respiratory viruses, nor antibody titers to vaccination, but they decrease the expression of cytokines induced by the viral infection, including il6, tnf-α and ifn-β [26] [27] [28] . other anti-inflammatory effects of vitamin d include modulation of macrophage chemotactic protein1, interleukin 8, type 1 interferon, tnfα and lowering of oxygen reactive species [26, 29] . the efficacy of vitamin d trials in patients with influenza infections is not well established [25, 27, 28] . prevention trials, mostly conducted in the pediatric age group, are negative [28, [30] [31] [32] [33] [34] [35] [36] [37] . however, two systematic reviews of controlled trials showed promising results. the first investigating the effectiveness of vitamin d in the prevention or treatment of infectious diseases reported that the strongest evidence was in reducing the risk of acute respiratory illness and influenza [38] . more recently, an individual patient meta-analysis of 25 trials, of over 11,000 participants, showed vitamin d supplementation to reduce the risk of acute respiratory infections, including viral, by 12% in all participants. this effect was noted with daily or weekly doses (by 19%), but not bolus doses, and was most pronounced in patients with serum 25(oh)d levels below 50 nmol/l (20 ng/ml) [39] . the evidence from trials in critically ill patients is also mixed. vitamin d had no significant effects on mortality, ventilation, or length to stay in one meta-analysis [40] , while it was associated with a 30% reduction in mortality compared to placebo, in another [41] . finally, the most recent randomized trial of 1,360 icu patients reported that early administration of 540,000 iu of vitamin d3 did not improve 90 day mortality [42] . differences in inclusion criteria, diseases treated, baseline 25(oh)d levels, and regimens used (doses, regimens, and formulations), in trials included in these 2 meta-analyses may explain opposing results. j o u r n a l p r e -p r o o f (ncrc) on pharmaceutical interventions [43] , who primary trial registries [44] , and clinicaltrials.gov what are optimal doses of the sunshine vitamin in covid-19 times? vitamin d3 supplementation, daily or weekly, at daily equivalent doses of 1,000-4,000 iu, is advisable. the wide range targets a desirable 25 (oh) > 75 nmol/l (30 ng/ml). both accommodate the anticipated higher needs across the lifespan incurred by lockdown measures, immobilization, and hospitalization. they also allow flexibility in tailoring doses to individual needs, factoring in considerations such as prevention or treatment, baseline risks, covid-19 status and health care settings. importantly, our approach is anchored in abundant safety data across the life course [6] , not exceeding the upper tolerable level [46] . it is based on clear evidence for efficacy in fracture risk reduction and possibly falls in institutionalized individuals [7] , an important consideration in frail covid-19 patients. it is also well aligned with recommendations from the center for evidence based medicine [47] . alternative guidance has been proposed. preventive doses of vitamin d3 of 10,000 iu/d for 4 weeks followed by 5,000 iu/day to reach a target 25(oh)d level of 100-150 nmol/l [24] , and treatment doses >6,000 iu/day in deficient individuals to reach a similar level and reduce disease progression [48] , are suggested. the former is based on a publication on the role of vitamin d in influenza and pneumonia, and a target level associated with a reduction in viral respiratory infections in one observational study [24] . the latter is based on indirect evidence derived from a single study in tuberculosis patients [48] . however, loading doses do not seem to have added beneficial effect on acute respiratory infections [39] , may adversely affect fall and fracture outcomes [49, 50] , and possibly other covid-19 respiratory outcomes. major gaps are to be references 17 and 20 are from pre-print, non-peer reviewed papers. they were not used as evidence to derive specific guidance in this commentary covid-19 -navigating the uncharted covid-19 and african americans severe outcomes among patients with coronavirus disease 2019 (covid-19) -united states skeletal and extraskeletal actions of vitamin d: current evidence and outstanding questions serum 25-hydroxyvitamin d levels: variability, knowledge gaps, and the concept of a desirable range impact of vitamin d supplementation on falls and fractures-a critical appraisal of the quality of the evidence and an overview of the available guidelines the role of vitamin d in the prevention of coronavirus disease editorial: low population mortality from covid-19 in countries south of latitude 35 degrees north supports vitamin d as a factor determining severity editorial: low population mortality from covid-19 in countries south of latitude 35 degrees north-supports vitamin d as a factor determining severity. authors' reply severe obesity is associated with higher in-hospital mortality in a cohort of patients with covid-19 in the high prevalence of obesity in severe acute respiratory syndrome coronavirus-2 (sars-cov-2) requiring invasive mechanical ventilation. obesity (silver spring) vitamin d-endocrine system body mass index, vitamin d, and type 2 diabetes: a systematic review and meta-analysis obesity and vitamin d deficiency: a systematic review and meta-analysis vitamin d supplementation in obesity and during weight loss: a review of randomized controlled trials vitamin d status, body mass index, ethnicity and covid-19: initial analysis of the first-reported uk biobank covid-19 positive cases (n 580) compared with negative controls vitamin d concentrations and covid-19 infection in uk biobank 25-hydroxyvitamin d concentrations are lower in patients with positive pcr for sars-cov-2 vitamin d deficiency as risk factor for severe covid-19: a convergence of two pandemics acute respiratory tract infection and 25-hydroxyvitamin d concentration: a systematic review and meta-analysis imaging and clinical features of patients with 2019 novel coronavirus sars-cov-2: a systematic review and meta-analysis the trinity of covid-19: immunity, inflammation and intervention evidence that vitamin d supplementation could reduce risk of influenza and covid-19 infections and deaths vitamin d and influenza. advances in nutrition modulation of the immune response to respiratory viruses by vitamin d vitamin d decreases respiratory syncytial virus induction of nf-kappab-linked chemokines and cytokines in airway epithelium while maintaining the antiviral state vitamin d and influenza-prevention or therapy? the impact of vitamin d levels on inflammatory status: a systematic review of immune cell studies impact of vitamin d supplementation on influenza vaccine response and immune functions in deficient elderly persons: a randomized placebo-controlled trial effect of vitamin d supplementation to reduce respiratory infections in children and adolescents in vietnam: a randomized controlled trial. influenza other respir viruses preventive effects of vitamin d on seasonal influenza a in infants: a multicenter, randomized, open, controlled clinical trial effect of high-dose vs standard-dose wintertime vitamin d supplementation on viral upper respiratory tract infections in young healthy children impact of vitamin d administration on immunogenicity of trivalent inactivated influenza vaccine in previously unvaccinated children effects of vitamin d supplements on influenza a illness during the 2009 h1n1 pandemic: a randomized controlled trial randomized trial of vitamin d supplementation to prevent seasonal influenza a in schoolchildren calcitriol (1,25-dihydroxy-vitamin d3) coadministered with influenza vaccine does not enhance humoral immunity in human volunteers vitamin d for treatment and prevention of infectious diseases: a systematic review of randomized controlled trials vitamin d supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data vitamin d supplementation in the critically ill: a systematic review and meta-analysis vitamin d and outcomes in adult critically ill patients. a systematic review and meta-analysis of randomized trials the national heart l, and blood institute petal clinical trials network. early high-dose vitamin d3 for critically ill, vitamin d-deficient patients primary registries in the who registry network the 2011 report on dietary reference intakes for calcium and vitamin d from the institute of medicine: what clinicians need to know perspective: improving vitamin d status in the management of covid-19 annual high-dose oral vitamin d and falls and fractures in older women: a randomized controlled trial monthly high-dose vitamin d treatment for the prevention of functional decline: a randomized clinical trial key: cord-310738-fnsf2qqm authors: yalcin bahat, pinar; aldikactioglu talmac, merve; bestel, ayşegul; topbas selcuki, nura f; aydın, zelal; polat, i̇brahim title: micronutrients in covid-19 positive pregnancies date: 2020-09-23 journal: cureus doi: 10.7759/cureus.10609 sha: doc_id: 310738 cord_uid: fnsf2qqm pregnant women are considered among the high-risk population for covid-19. therefore, research for methods of treatment and prevention of covid-19 positive pregnancies carries an importance. the aim of this study was to measure serum 25(oh)d, vitamin b12, and zinc levels in covid-19 positive pregnant women to evaluate the role of these micronutrients in treatment and prevention. a total of 44 covid-19 positive pregnant women who were hospitalized and treated at a tertiary clinic were included in this study. the mean serum 25(oh)d level was measured to be 9.70 ± 59.14. the mean serum zinc level was 62.58 ± 2.63, and the mean serum vitamin b12 level was 295.55 ± 302.48. all these variables were significantly lower than the accepted cut-off values (p < 0.001). these low values might have contributed to a deficiency in their immune response and thus made these patients susceptible to covid-19 infection. supplementation of micronutrients during the pandemic could be beneficial during pregnancy for prevention. coronavirus family has long been a well-known source of infection causing diseases like common cold, severe acute respiratory syndrome (sars), and middle east respiratory syndrome (mers). novel coronavirus 2019 (sars-cov-2) is a newly discovered virus from the coronavirus family, which is the infection source of the covid-19 pandemic [1]. covid-19 enters the host cells and triggers an immune response, which includes the production of proinflammatory cytokines, activation of t cells, cd4, and cd8+ t cells [2] . the severe forms of the disease leading to acute respiratory distress syndrome have been attributed to excessive production of proinflammatory cytokines also called 'cytokine storm' [3] . since the outbreak, extensive research has been put into understanding the action mechanism of covid-19 in hope of finding a cure and a vaccine. however, there are still unknowns especially about the potential protective factors against the virus. vitamins and minerals, also known as micronutrients, are key factors in maintaining a healthy immune system and therefore are widely used as supplements for protection against bacterial and viral infections [4] . zinc, 25 hydroxyvitamin d (25(oh)d), and vitamin b12 belong to this family of micronutrients. zinc is an essential micronutrient that is involved in cell proliferation, differentiation, rna and dna synthesis [5] , as well as cell structures and cell membrane stabilization [6] . there is also strong evidence between zinc deficiency and several infectious diseases, such as malaria, hiv, tuberculosis, measles, and pneumonia. zinc is also involved in the modulation of the proinflammatory response by regulation of inflammatory cytokines and in controlling oxidative stress [7] . similarly, 25(oh)d has anti-infective, antiinflammatory, and immunomodulant functions. it contributes to the maintenance of the cell's physical barrier integrity, enhanced activity of innate immunity through macrophages and monocytes, and t cells [8] . lastly, vitamin b12 is a water-soluble vitamin. it is a cofactor in dna synthesis and is known to inhibit viral replication in the host cells [9] . the aim of this study was to measure serum 25(oh)d, vitamin b12, and zinc levels in covid-19 positive pregnant women to evaluate the role of these micronutrients in the prevention and to evaluate the possible cause between the blood levels of micronutrients and the covid-19 infection. this case-control study was conducted in a tertiary referral hospital between april and june 2020. the study protocol was approved by the institution's ethics committee (2020.05.25) and registered to clinicaltrials.gov (nct04407572). written informed consent was obtained from all participants before their enrollment in the study. a total of 44 covid-19 positive pregnant women were included in the study. pregnant women whose pcr test was positive for covid-19, pregnancies older than eight weeks of gestation, and women who did not receive any antibacterial or antiviral treatment during the past three months or did not receive any 25(oh)d, vitamin b12, and zinc supplements during their pregnancy were included in the study. women with known renal disease, rheumatic disease, diabetes mellitus type 1, acquired immune deficiency syndrome, and those using immunosuppressants were excluded. complicated pregnancies such as ectopic pregnancy, scar pregnancy, or hydatidiform mole were also excluded. a detailed medical history was obtained. all patients underwent a physical and obstetrical examination with ultrasound and received a thorax ct. in addition to routine blood tests, d-dimer levels and ferritin levels were also determined. gestational age was estimated based on the last menstrual period. if the date of the last menstruation was unknown, then crown-rump length (crl) was used for calculation. on the day of admission, blood samples were taken from a peripheral vein using one dry tube and one tube with ethylenediaminetetraacetic acid (edta). tubes were submitted to the hospital's central laboratory for determination of 25(oh)d, zinc, and vitamin b12 levels. quantitative determination of 25(oh)d was performed with competitive chemiluminescent immunoassay (clia) using liaison® 25 oh vitamin d total assay (diasorin s. p. a., saluggia, italy). vitamin d deficiency was defined as serum vitamin d levels of less than 20 ng/ml, insufficiency as 21-29 ng/ml, and sufficiency as 30-100 ng/ml according to recent clinical guidelines committee. recommended levels are higher than 30 ng/ml for specific groups, such as in pregnant women. the mean of 19.9 ng/ml (sd: 0.948 ng/ml and an intra-control cv of 4.8%) was the referred reproducible value to measure the 25(oh)d. for the same parameter, the intermediate precision was 19 .9 ng/ml (sd: 1.23 ng/ml and an intra-control cv of 6.2%) [10] . access immunoassay system (© 2020beckman coulter inc., brea, ca, usa) was used to quantitate serum vitamin b12 levels. a normal range of 100-350 pmol/l serum vitamin b12 was calculated with a 95% confidence interval [11] . for zinc quantification, atomic absorption spectroscopy was used (perkinelmer® inc., waltham, ma, usa). current cut-off levels for zinc deficiency are <8.7 μmol/l (afternoon, non-fasting) and for non-fasting women of reproductive age (aged 18-49 years; wra, <10.1 μmol/l (morning) and <9.0 μmol/l (afternoon)) [12] . all calculations followed the best clinical practice. statistical package for social sciences 23.0 (ibm corp., armonk, ny, usa) was used for statistical analysis. descriptive statistical methods (mean, standard deviation, frequency) and their associated 95% confidence intervals of study variables were presented. one sample t-test was performed to evaluate the difference between accepted cut-off values and the means of our study groups regarding b12, zinc, and 25(oh)d levels. p-value <0.05 was considered for statistical significance. a total of 44 covid-19 positive pregnant women were included in the study. the mean age was 28.57 ± 7.77 years. when pregnancies were divided into trimesters, it was observed that disease rate in our cohort increased with increasing trimester: 8.8% (n = 5) was in the first trimester, 27.2% (n = 12) were in the second trimester, and 61.3% (n = 27) were in the third trimester. the mean gravidity was 2.75 ± 1.74, and the mean parity was 1.32 ± 1.37 (table 1) . when thorax cts were evaluated, 38.63% (n = 17) did not reveal any pathology, 27.327% (n = 12) showed mild changes, and in 27.27% (n = 12) moderate and in 6.81% (n = 3) severe findings could be observed. majority of the patients in the study presented with mild to moderate ct findings. approximately 40.90% were treated with hydroxychloroquine, whereas 59.10% were monitored actively without any medical intervention. at the time of admission, the mean serum d-dimer level was 1.72 ± 0.91 and the ferritin level was 64.10 ± 187.62. the mean duration of stay at the hospital was 6.63 ± 1.70 (3-11) ( table 1) . while the minimum stay in the hospital was 3 days and the maximum stay was 11 days. the mean serum 25(oh)d level was measured to be 9.70 ± 59.14. the mean serum zinc level was 62.58 ± 2.63, and the mean serum vitamin b12 level was 295.55 ± 302.48 (table 1 ). in one sample t-test analysis, all these variables were significantly lower than the accepted cut-off values (p-value <0.001): 25(oh)d: 30, zinc: 10.1, and b12: 100. understanding the pathogenesis of sars-cov-2 has been challenging, and it has not yet been clarified. however, covid-19 affects the immune system in many different steps in the disease process [13] . micronutrients are among these immune supplements, and their efficacy has already been shown with other viral infections [14] . previous studies conducted with pregnant women and women in the postpartum period have shown the efficacy of micronutrients in fight against viral infections. especially, the inhibitory effects of 25(oh)d, vitamin b12, and zinc, due to their safe use during pregnancy, on viral pathogenesis have already been shown. for example, in studies of h1n1 prior to the finding of a vaccine, the protective effects of high levels of vitamin b12 on the newborns ingested through breast milk were observed [15] . another study has shown that high levels of maternal serum 25(oh)d levels during pregnancy and lactation were associated with lower rates of acute respiratory infections of the newborns [16] . additionally, it has been shown that serum zinc levels correlate positively with better immune response in pregnant women against infections [17] . it is known that 25(oh)d plays an essential role in immune answer and its modulation [18, 19] . in a study conducted by ilie et al., in countries that had a severe course of covid-19 such as spain, italy, and the united kingdom, mean serum 25(oh)d levels are low [20] . another study showed that patients with high serum vitamin d levels sustained less lung damage. according to a study by alipio, lower rates of multiple organ failure were observed among patients with higher levels of serum 25(oh)d [21] . from the existing evidence, it can be concluded that the suppression of viral replication by 25(oh)d is effective in the prevention and also responsible for a mild course of covid-19 [22] . in our study, serum 25(oh)d levels of the covid-19 positive pregnant women were under the cutoff value. the reason for these low values could be pregnancy, less exposure to sunlight, and insufficient nutrition. the low levels of serum 25(oh)d, in accordance with the existing data, might have caused susceptibility to covid-19. zinc plays an important role in the pathogenesis of viral infections. the correlation between serum zinc levels and the severity of infections has already been shown [7] . anosmia, a common symptom of covid-19, is also seen in zinc deficiency [23] . in three women, included in the study, with very low levels of serum zinc, anosmia was among the symptoms. shittu and afolami advocated in their study that adding zinc supplements to the treatment regimen with chloroquine in covid-19 patients enhanced the antiviral action mechanism of the chloroquine and efficacy of the treatment [24] . according to another study, it has been suggested that zinc could possess protective effects through reducing inflammation, improving mucociliary clearance, preventing ventilator-induced lung injury, and modulating antiviral and antibacterial immunity [25] . therefore, zinc can be used both as preventative medication and adjuvant therapy of covid-19. similar to the results with 25(oh)d, zinc levels were significantly low in our patient cohort, which might have played a negative effect on their immunity making these patients susceptible during the pandemic. in vivo studies of vitamin b12 have shown that vitamin b12 acts as a natural inhibitor of viral replication of the hepatitis c virus (hcv) [26] . in another study, it was shown that vitamin b12 and folate levels affect the human papillomavirus methylation process and low serum levels increase malignancy [27] . in our study, all serum vitamin b12 levels were significantly low can be making them more prone to covid-19. there are several limitations to this study. first, there are difficulties in the measurement of serum 25(oh)d levels in pregnant women, which might have led to the lower levels observed in this study. additionally, a limited number of patients and a lack of a control group were further limitations. however, due to the need for cumulative data concerning the covid-19 pandemic, we believe that our results will be of importance for further studies on prevention and adjuvant therapy. the level of serum micronutrients in pregnant women with covid-19 was lower than the cut-off values. these low values might have contributed to a deficiency in their immune response and thus made these patients susceptible to covid-19 infection. supplementation of micronutrients during the pandemic could be beneficial during pregnancy for prevention. however, further studies are needed to show their effects on covid-19 infection. human subjects: consent was obtained by all participants in this study. kanuni sultan suleyman hospital issued approval kaek/2020.05.25. registered to clinicaltrials.gov (nct04407572). . animal subjects: all authors have confirmed that this study did not involve animal subjects or tissue. conflicts of interest: in compliance with the icmje uniform disclosure form, all authors declare the following: payment/services info: all authors have declared that no financial support was received from any organization for the submitted work. financial relationships: all authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. other relationships: all authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work. zinc and the immune system coordination dynamics of zinc in proteins zinc and human disease . interrelations between essential metal ions and human diseases association between vitamin d supplementation and mortality: systematic review and meta-analysis association of serum vitamin b 12 levels with stage of liver fibrosis and treatment outcome in patients with chronic hepatitis c virus genotype 1 infection: a retrospective study vitamin d insufficiency a review of the cut-off points for the diagnosis of vitamin b12 deficiency in the general population determination of zinc status in humans: which indicator should we use? coronavirus infections and immune responses optimal nutritional status for a well-functioning immune system is an important factor to protect against viral infections vitamin b12 supplementation during pregnancy and postpartum improves b12 status of both mothers and infants but vaccine response in mothers only: a randomized clinical trial in bangladesh maternal vitamin d supplementation during pregnancy and lactation to prevent acute respiratory infections in infancy in dhaka, bangladesh (mdari trial): protocol for a prospective cohort study nested within a randomized controlled trial peculiarities of changes in indices of calcium and zinc trace elements and matrix metalloproteinase-2 in pregnant women with perinatal infections covid-19 and vitamin d-is there a link and an opportunity for intervention? spanish vitamin d and women's health research group: hypovitaminosis d during pregnancy: are we ready to recommend vitamin d supplementation? the role of vitamin d in the prevention of coronavirus disease 2019 infection and mortality vitamin d supplementation could possibly improve clinical outcomes of patients infected with coronavirus-2019 (covid-19 optimisation of vitamin d status for enhanced immuno-protection against covid-19 re-establishment of olfactory and taste functions improving the efficacy of chloroquine and hydroxychloroquine against sars-cov-2 may require zinc additives-a better synergy for future covid-19 clinical trials zinc and respiratory tract infections: perspectives for covid-19 vitamin b12 supplementation improves rates of sustained viral response in patients chronically infected with hepatitis c virus folate and vitamin b12 may play a critical role in lowering the hpv 16 methylation-associated risk of developing higher grades of cin the authors would like to thank assistant professor cihan kaya for his support and advice. key: cord-284193-qslc2wry authors: malek mahdavi, aida title: a brief review of interplay between vitamin d and angiotensin‐converting enzyme 2: implications for a potential treatment for covid‐19 date: 2020-06-25 journal: rev med virol doi: 10.1002/rmv.2119 sha: doc_id: 284193 cord_uid: qslc2wry the novel coronavirus disease 2019 (covid‐19) is rapidly expanding and causing many deaths all over the world with the world health organization (who) declaring a pandemic in march 2020. current therapeutic options are limited and there is no registered and/or definite treatment or vaccine for this disease or the causative infection, severe acute respiratory coronavirus 2 syndrome (sars‐cov‐2). angiotensin‐converting enzyme 2 (ace2), a part of the renin‐angiotensin system (ras), serves as the major entry point into cells for sars‐cov‐2 which attaches to human ace2, thereby reducing the expression of ace2 and causing lung injury and pneumonia. vitamin d, a fat‐soluble‐vitamin, is a negative endocrine ras modulator and inhibits renin expression and generation. it can induce ace2/ang‐(1‐7)/masr axis activity and inhibits renin and the ace/ang ii/at1r axis, thereby increasing expression and concentration of ace2, masr and ang‐(1‐7) and having a potential protective role against acute lung injury (ali)/acute respiratory distress syndrome (ards). therefore, targeting the unbalanced ras and ace2 down‐regulation with vitamin d in sars‐cov‐2 infection is a potential therapeutic approach to combat covid‐19 and induced ards. pulmonary and rheumatic diseases. 2 this newly emerging disease imposes a lot of negative impacts on the economy and healthcare structures in affected countries. currently, therapeutic options are limited and there is no registered and/or definite treatment or vaccine for this problem. alternative solutions to prevent and control this virus are therefore desirable. vitamin d is a fat-soluble micronutrient and also a hormone produced in body from sunlight. besides its function in preserving bone integrity, it has a role in maturation of different cells such as immune cells. 5 vitamin d deficiency is identified as a global public health matter and numerous investigations have reported that poor vitamin d status can affect a variety of diseases. 6 a majority of healthy individuals have low vitamin d concentration, mainly at the end of the winter. 5 furthermore, individuals who stay at home or institution as well as night workers and elderly subjects, who have low exposure to sunlight, may suffer from vitamin d deficiency. 6 since covid-19 was recognized in winter 2019 and mainly influenced middle-aged and elderly subjects, it has been supposed that virus-infected subjects may not have adequate vitamin d levels. even though the mechanisms responsible for vitamin d function in the host immune system have been explained, 7, 8 the interplay between viral infections and vitamin d remains a confusing matter, and plausible interactions between viral infections and vitamin d do not appear to be simple. angiotensin-converting enzyme 2 (ace2), a part of the reninangiotensin system (ras), serves as the major entry point into cells for some coronaviruses such as hcov-nl63, sars-cov and sars-cov-2 that cause sars and covid-19, respectively. [9] [10] [11] [12] it has also been shown that sars-cov-2 attaches to human ace2 through its spike glycoprotein, thereby reducing the expression of ace2 and causing lung injury and pneumonia. [12] [13] [14] [15] therefore, considering the importance of vitamin d in ras and regulating ace and ace2, 16 we supposed that vitamin d could be considered as a potential therapeutic option for this novel coronavirus. this narrative mini-review has been conducted using an online search on pubmed and google scholar in order to discuss the potential pathways connecting vitamin d, covid-19 and its therapy, with a focus on the ras and ace2. coronaviruses, the viruses with the largest single stranded-rna genome, belong to the family of coronaviridae. 17 coronaviruses cause enzootic diseases in birds and mammals, including humans. 18 furthermore, the host immune response can be essential for the pathogenesis of clinical features. 19 when the virus binds to the host cells via its target receptor and enters the cells, its antigen will be presented to the antigen presentation cells (apc), which is a central part of the body's anti-viral immunity. antigen presentation then stimulates the body's humoral and cellular immunity, which are mediated by virusspecific b and t cells. the antibody profile against acute viral infections including sars-cov and sars-cov-2 has a typical pattern of igm and igg production. 20 moreover, the number of cd4+ and cd8+ t cells decreased significantly in the peripheral blood of infected patients. 20 in addition, the inflammatory response and secretion of cytokines and chemokines, which occurs during acute viral infections like sars-cov and sars-cov-2 attracts immune cells, particularly monocytes and t lymphocytes from the blood into the infected site. 21 in most subjects, recruited cells clear the infection in the lung, the immune response recedes and patients recover. 21 however, in some patients, a dysfunctional immune response occurs, which triggers a cytokine storm that mediates extensive lung inflammation. 21 ace2 is a part of the ras identified in 2000. 22 it is the human homologue of ace but is different from ace in substrate specificity. 22 ace2 is a membrane protein found in nearly all body tissues with relatively higher expression in respiratory epithelial cells, alveolar cells type i and ii, heart, kidney, blood vessels and the gastrointestinal tract. 9,23,24 ace2 catalyzes the cleavage of angiotensin ii (ang ii) (a vasoconstrictor peptide) into angiotensin 1-7 [ang-(1-7)] (a vasodilator), thereby reducing blood pressure. 25 ang-(1-7) stimulates nitric oxide synthase (nos) and further antagonizes ang ii activity through its at1 receptor. 26 it seems that ace/ace2 ratio has a considerable impact on various diseases like diabetes, hypertension, and nephropathy. 27 ace2is also the receptor on host cell surface and the major entry point into cells for some coronaviruses such as hcov-nl63, covid-19. 9-12 sars-cov-2 binds to human ace2 through its spike glycoprotein and reduces ace2 expression, thereby causing excessive generation of angii via the enzyme ace. ang ii has been demonstrated to stimulate cell growth and proliferation of lung fibroblasts 28, 29 and up-regulates the expression of transforming growth factor-β (tgf-β), 30 a central player in fibrogenesis that is associated with the differentiation of fibroblast to myofibroblasts, which dramatically increases extracellular matrix protein deposition. 31 ang ii is involved in lung inflammation through the generation of reactive oxygen species and the release of proinflammatory cytokines. 32, 33 ang ii has been shown to induce alveolar epithelial cell apoptosis, 34 which is believed to initiate the fibrotic process and is also involved in promoting procoagulatory effects through activating plasminogen activator inhibitor-1. 35 induction of type 1a ang ii receptor (agtr1a) enhances pulmonary vascular permeability, thereby causing lung injury and pneumonia; this possibly explains the lung damage following decreasing ace2 expression. [12] [13] [14] [15] in an animal study of ards, ace2 knockout mice exhibited intense lung disease, characterized by increases in vascular permeability and lung edema. 36 also, ace2 overexpression decreased lipopolysaccharide (lps)-induced ards through the ang-(1-7)/mas pathway by suppressing extracellular signal-regulated kinase/nuclear factor-κb (nf-κb) activation. 37 increase in the ace/ace2 ratio that occurs during covid-19 presumably affects kidney damage initiation. 26 meanwhile, ace2 affects biologic peptides outside the ras such as the kinin-kallikrein system, apelin-13 and dynorphin a peptide. these peptides can be elevated and impose unfavorable effects by attenuatingace2 expression. 38 furthermore, ace2 hydrolyzes the active bradykinin metabolite dabk (desarg 9 -bradykinin). 39 a decreased activity of ace2 impairs the inactivation of dabk and therefore, enhances its signaling through bradykinin b1 receptor (bkb1r). as a consequence, fluid extravasation and leukocyte recruitment to the lung occur. 40 55, 56 compared to subjects with sufficient 25(oh)d levels (≥30 ng/ml), those with insufficiency (15-29.9 ng/ml) and deficiency (<15 ng/ml) had higher circulating ang ii concentrations. furthermore, those with vitamin d deficiency had significantly blunted renal plasma flow responses to infused ang ii. 57 since there is no clear definition regarding the optimal concentration of vitamin d to use in different clinical settings including patients with covid-19, so this fact may impact its interaction with ace2 in covid-19. persistent deficiency in vitamin d level may activate the ras, thereby leading to chronic cvd and decreased lung function as well as inducing ras activation lung fibrosis. 58 patients with these comorbidities account for a higher proportion of critically ill cases in covid-19. 58 the covid-19 infection becomes more severe especially in elderly, hypertensive, diabetic and obese patients and smokers. 59 particularly in the presence of diabetes mellitus and accompanying comorbid conditions such as hypertension, obesity, old age and smoking, cytosolic ph is low, thus the virus easily may enter the cell by attaching to ace2. 60, 61 especially in elderly patients with diabetes, covid-19 infection will be more severe since cytosolic ph is lower. 61 recently, it has been reported that cvd or ras blockade medications may increase ace2 levels, augmenting available substrate for sars-cov-2 infection. 62 furthermore, circulating ace2, shed from endothelial cells is a biomarker of hypertension and heart failure 63 as well as diabetes, 64 reflecting increased ace2 activity. sars-cov-2 infection down-regulates ace2 activity, resulting in toxic ang ii over-accumulation which in turn may cause ards or fulminant myocarditis. 62 in addition, some medications such as antibiotics, anti-inflammatory agents, antihypertensives and endocrine drugs decrease serum 25(oh)d levels via activating the pregnane-x receptor. 65 medication use usually increases with age. 65 therefore, normalization of vitamin d concentrations can lower ras activity by transcriptional suppression of renin expression. 66 xu et al 54 also showed that vitamin d suppressed renin, ace and angii expression and increased ace2 concentration in lps-induced ali. thus, vitamin d may decrease lps-induced ali by inducing ace2/ang-(1-7) axis and suppressing renin and the ace/ang ii/at1r axis. 54 in another study by yang et al, 67 1,25(oh)2d3 enhanced mrna expression of vdr and ace2 as well as vdr and ace2 levels in rat models of lps-induced ali compared to controls, indicating that increased expression of ace2 mrna and vdr mrna had a role in protection against ali development. furthermore, clinical features and pathological changes of lung tissues in the calcitriol-treated lps rats were remarkably milder than controls. 67 lin et al 68 observed that calcitriol decreased ace concentration and ace/ace2 ratio and enhanced ace2 concentration in diabetic rats. in addition, calcitriol treatment remarkably suppressed p38 mitogen-activated protein kinase and extracellular signal-regulated kinase (erk) phosphorylation, but not c-jun n-terminal kinases phosphorylation, and effectively weakened ace upregulation and ace2 down-regulation. 68 accordingly, administration of the synthetic vitamin d analog, paricalcitol, led to increased levels of ace2 in tubular cells and decreased levels of ace2 within the circulation in an animal model of type i diabetes, thereby slowing the development of diabetic nephropathy. 69 cui et al 70 production. 70 the proposed potential therapeutic effect of vitamin d for covid-19 and induced ards is summarized in figure 1 . while the beneficial effects of vitamin d on covid-19 infection are mainly from observational studies of disease incidence or prevalence with respect to serum 25(oh)d concentrations, 43 most vitamin d randomized clinical trials have not declared that vitamin d supplementation reduced the risk of non-skeletal disorders. 71, 72 although it is more likely that any protective effect of vitamin d against covid-19 is related to suppression of cytokine response and reduced severity/risk for ards, there is also evidence from a meta-analysis that regular oral vitamin d2/d3 intake (in doses up to 2000 iu/day) is safe and protective against acute respiratory tract infection, especially in subjects with vitamin d deficiency. 73 thus, it seems possible that vitamin d prophylaxis (without over-dosing) may decrease the severity of illness caused by sars-cov-2, especially in settings where hypovitaminosis d is common. 74 rhodes et al 75 also indicated that it would be reasonable to consider vitamin d supplementation to protect musculoskeletal health in those at risk of deficiency due to being housebound. moreover, marik et al 76 suggested that vitamin d deficiency may partly explain the geographic variations in the reported case fatality rate of covid-19, indicating that supplementation with vitamin d may reduce the mortality from this pandemic. in addition, significant relationship was observed between vitamin d levels and the number covid-19 cases and especially the mortality caused by this infection. 77 the most vulnerable group of population for covid-19 is also the one that has the most deficit in vitamin d. 77 to reduce the risk of infection, it is recommended that individuals at risk of covid-19 take 10 000 iu/day of vitamin d3 for a few weeks to rapidly increase 25(oh)d levels above 40-60 ng/ml, followed by 5000 iu/day. 43 for treatment of subjects who become infected with covid-19, higher vitamin d3 doses might be useful. 43 taking into account the above-mentioned evidence, it seems that targeting the unbalanced ras and ace2 down-regulation with vitamin d in sars-cov-2 infection may be a potential therapeutic approach to combat the expanding of covid-19 and induced ards. the authors have no competing interest. https://orcid.org/0000-0003-0176-5438 a pneumonia outbreak associated with a new coronavirus of probable bat origin clinical features of patients infected with 2019 novel coronavirus in wuhan clinical course and outcomes of critically ill patients with sars-cov-2 pneumonia in wuhan, china: a single-centered, retrospective, observational study vitamin d insufficiency among free-living healthy young adults sunlight and vitamin d for bone health and prevention of autoimmune diseases, cancers, and cardiovascular disease vitamin d: nutrient, hormone, and immunomodulator impact of vitamin d on immune function: lessons learned from genome-wide analysis evolution of the novel coronavirus from the ongoing wuhan outbreak and modeling of its spike protein for risk of human transmission coronaviruses: an overview of their replication and pathogenesis receptor recognition and cross-species infections of sars coronavirus a crucial role of angiotensin converting enzyme 2 (ace2) in sars coronavirus-induced lung injury angiotensin-converting enzyme 2 is a functional receptor for the sars coronavirus structure analysis of the receptor binding of 2019-ncov genomic characterization and epidemiology of 2019 novel coronavirus: implications for virus origins and receptor binding molecular mechanism of vitamin d in the cardiovascular system bats and coronaviruses coronavirus envelope protein: current knowledge sars-cov-2 cell entry depends on ace2 and tmprss2 and is blocked by a clinically proven protease inhibitor molecular immune pathogenesis and diagnosis of covid-19 the trinity of covid-19: immunity, inflammation and intervention a novel angiotensin converting enzyme-related carboxypeptidase (ace2) converts angiotensin i to angiotensin 1-9 quantitative mrna expression profiling of ace 2, a novel homologue of angiotensin converting enzyme high expression of ace2 receptor of 2019-ncov on the epithelial cells of oral mucosa ace2 of the heart: from angiotensin i to angiotensin (1-7) ace and ace2 in kidney disease the discovery of angiotensinconverting enzyme 2 and its role in acute lung injury in mice angiotensin ii is mitogenic for human lung fibroblasts via activation of the type 1 receptor angiotensin ii and the fibroproliferative response to acute lung injury angiotensin-tgf-beta 1 crosstalk in human idiopathic pulmonary fibrosis: autocrine mechanisms in myofibroblasts and macrophages abrogation of tgf-beta1-induced fibroblast-myofibroblast differentiation by histone deacetylase inhibition role of oxidative stress in pulmonary fibrosis effects of angiotensin on the expression of fibrosis-associated cytokines, growth factors, and matrix proteins in human lung fibroblasts angiotensin ii induces apoptosis in human and rat alveolar epithelial cells oxidative stress, plasminogen activator inhibitor 1, and lung fibrosis angiotensin-converting enzyme 2 protects from severe acute lung failure angiotensin-converting enzyme 2 prevents lipopolysaccharide-induced rat acute lung injury via suppressing the erk1/2 and nf-κb signaling pathways the role of bradykinin in lung ischemia-reperfusion injury in a rat lung transplantation model hydrolysis of biological peptides by human angiotensin-converting enzyme-related carboxypeptidase attenuation of pulmonary ace2 activity impairs inactivation of des-arg(9) bradykinin/ bkb1r axis and facilitates lps-induced neutrophil infiltration vitamin d: modulator of the immune system evidence that vitamin d supplementation could reduce risk of influenza and covid-19 infections and deaths vitamin d and 1,25(oh)2d regulation of t cells letter: covid-19, and vitamin d. authors' reply aliment pharmacolther d3) pre-and post-treatment suppresses inflammatory response to influenza a (h1n1) infection in human lung a549 epithelial cells vitamin d deficiency contributes directly to the acute respiratory distress syndrome (ards) vitamin d deficiency and acute lung injury vitamin d deficiency: a factor in covid-19, progression, severity and mortality?-an urgent call for research. mito fit preprint arch vdr attenuates acute lung injury by blocking ang-2-tie-2 pathway and renin-angiotensin system effect of vitamin d deficiency in korean patients with acute respiratory distress syndrome the association of vitamin d status with acute respiratory morbidity in preterm infants vitamin d/vdr signaling attenuates lipopolysaccharide-induced acute lung injury by maintaining the integrity of the pulmonary epithelial barrier vitamin d alleviates lipopolysaccharide-induced acute lung injury via regulation of the renin-angiotensin system vitamin d: a negative endocrine regulator of the renin-angiotensin system and blood pressure 1,25-dihydroxyvitamin d(3) is a negative endocrine regulator of the reninangiotensin system independent association between 1,25-dihydroxyvitamin d, 25-hydroxyvitamin d and the reninangiotensin system: the ludwigshafen risk and cardiovascular health (luric) study chronic vitamin d deficiency induces lung fibrosis through activation of the renin-angiotensin system comment on organ-protective effect of angiotensin-converting enzyme 2 and its effect on the prognosis of covid-19 intracellular ph in human and experimental hypertension angiotensin-converting enzyme inhibitors and angiotensin receptor blockers may be harmful in patients with diabetes during covid-19 pandemic is there an association between covid-19 mortality and the renin-angiotensin system -a call for epidemiologic investigations new perspectives in the reninangiotensinaldosterone system (raas) iv: circulating ace2 as a biomarker of systolic dysfunction in human hypertension and heart failure circulating ace2 activity is increased in patients with type 1 diabetes and vascular complications influence of drugs on vitamin d and calcium metabolism 1,25-dihydroxyvitamin d3 suppresses renin gene transcription by blocking the activity of the cyclic amp response element in the renin gene promoter effect of vitamin d on ace2 and vitamin d receptor expression in rats with lps-induced acute lung injury calcitriol regulates angiotensin-converting enzyme and angiotensin converting-enzyme 2 in diabetic kidney disease paricalcitol modulates ace2 shedding and renal adam17 in nod mice beyond proteinuria vitamin d receptor activation regulates microglia polarization and oxidative stress in spontaneously hypertensive rats and angiotensin ii-exposed microglial cells: role of reninangiotensin system effect of vitamin d supplementation on non-skeletal disorders: a systematic review of meta-analyses and randomised trials non-skeletal health effects of vitamin d supplementation: a systematic review on findings from meta-analyses summarizing trial data vitamin d supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data letter: covid-19, and vitamin d editorial: low population mortality from covid-19 in countries south of latitude 35 degrees north supports vitamin d as a factor determining severity does vitamin d status impact mortality from sars-cov-2 infection how to cite this article: malek mahdavi a. a brief review of interplay between vitamin d and angiotensin-converting enzyme 2: implications for a potential treatment for covid-19 key: cord-265340-hc9003dj authors: merzon, eugene; tworowski, dmitry; gorohovski, alessandro; vinker, shlomo; golan cohen, avivit; green, ilan; frenkel morgenstern, milana title: low plasma 25(oh) vitamin d level is associated with increased risk of covid‐19 infection: an israeli population‐based study date: 2020-07-23 journal: febs j doi: 10.1111/febs.15495 sha: doc_id: 265340 cord_uid: hc9003dj aim: to evaluate associations of plasma 25(oh)d status with the likelihood of coronavirus disease (covid‐19) infection and hospitalization. methods: the study population included the 14,000 members of leumit health services who were tested for covid‐19 infection from february 1(st) to april 30(th) 2020, and who had at least one previous blood test for plasma 25(oh)d level. "suboptimal" or "low" plasma 25(oh)d level was defined as plasma 25‐hydroxyvitamin d, or 25(oh)d, concentration below the level of 30 ng/ml. results: of 7,807 individuals, 782 (10.1%) were covid‐19‐positive, and 7,025 (89.9%) covid‐19‐negative. the mean plasma vitamin d level was significantly lower among those who tested positive than negative for covid‐19 [19.00 ng/ml (95% confidence interval [ci] 18.41‐19.59) vs. 20.55 (95% ci 20.32‐20.78)]. univariate analysis demonstrated an association between low plasma 25(oh)d level and increased likelihood of covid‐19 infection [crude odds ratio (or) of 1.58 (95% ci 1.24‐2.01, p<0.001)], and of hospitalization due to the sars‐cov‐2 virus [crude or of 2.09 (95% ci 1.01‐ 4.30, p<0.05)]. in multivariate analyses that controlled for demographic variables, and psychiatric and somatic disorders, the adjusted or of covid‐19 infection [1.45 (95% ci 1.08‐1.95, p<0.001)], and of hospitalization due to the sars‐cov‐2 virus [1.95 (95% ci 0.98‐4.845, p=0.061)] were preserved. in the multivariate analyses, age over 50 years, male gender and low‐medium socioeconomic status were also positively associated with the risk of covid‐19 infection; age over 50 years was positively associated with the likelihood of hospitalization due to covid‐19. conclusion: low plasma 25(oh)d level appears to be an independent risk factor for covid‐19 infection and hospitalization. this article is protected by copyright. all rights reserved from its origin in wuhan, china in december 2019, the novel coronavirus disease, covid-19, caused by severe acute respiratory syndrome coronavirus 2 (sars-cov-2) virus, has spread rapidly throughout the world (1) . in israel, the first case of the covid-19 infection was reported on february 21, 2020. on march 11, 2020 the world health organization (who) declared covid-19 disease a global pandemic (2) . immediate targeted action is needed to identify risk factors of covid-19. the sars-cov-2 virus has high levels of transmissibility, estimated basic reproduction (ro) ranging from 2.6 to 4.7, and an average incubation duration ranging from 2 to 14 days (3) . the main routes of transmission are respiratory droplets and direct contact with contaminated objects and surfaces (4) . the status of the immune system is determined by a multitude of factors that may contribute to the risk of a viral infection (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) . vitamin d is recognized as an important co-factor in several physiological processes linked with bone and calcium metabolism, and also in diverse non-skeletal outcomes, including autoimmune diseases, cardiovascular diseases, diabetes type 2, obesity and cognitive decline and infections (16, 17) . in particular, the pronounced impact of vitamin d metabolites on the immune system response, and on the development of covid-19 infection by the novel sars cov-2 virus, has been described (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) . vitamin d deficiency has been recognized as a worldwide pandemic (18, 19) . we aimed to determine associations of low plasma 25(oh)d with the risk of covid-19 infection and hospitalization, using realworld data. we hypothesized that the mean plasma level of 25(oh)d would be significantly lower and, accordingly, the rate of suboptimal plasma 25(oh)d would be significantly higher, among persons testing positive for covid-19 infection, and among persons subsequently hospitalized, in a large population-based data study. this article is protected by copyright. all rights reserved covid-19 infections and different categories of plasma 25 (oh) d levels (table 1 ). in a primary univariate analysis, covid-19-p subjects were younger, and more likely to be males and to reside in a lower ses area than were covid-19-n subjects ( table 2, figures 2a). the mean plasma 25(oh)d level was significantly lower for covid-19-p subjects (table 2) , and the proportion with low vitamin d level was higher (89.90% vs. 84.91%, p<0.001) ( table 3 ). the prevalence of dementia, hypertension, cardiovascular disease and chronic lung disorders were greater among persons who were covid-19-n than those who were covid-19-p (p<0.05, p<0.001, p<0.001, p<0.001) ( table 4) . among the covid-19-p individuals, those who were hospitalized were older [ figure 3 ). this article is protected by copyright. all rights reserved the main finding of this study was the low plasma 25(oh)d level association with covid-19 hospitalization risks, for patients tested positively for covid-19, after adjusting for age, gender, ses and chronic, mental and physical disorders. hence, low 25(oh)d level was identified as independently associated with the likelihood of covid-19 infection. this finding is in agreement with the results of other studies (5, 7, (9) (10) (11) (12) (13) (14) (15) 19, (30) (31) (32) (33) (34) (35) (36) (37) (38) (39) (40) (41) (42) . further, reduced risk of acute respiratory tract infection following vitamin d supplementation has been reported (43, 44) . notably, a recent study from the uk (31-33) that included 449 subjects (from the uk biobank) with confirmed covid-19 infection did not find an association between vitamin d metabolite concentration and the risk of viral infections (45) as well as covid-19 infection (5, 7, (9) (10) (11) (12) (13) (14) (15) 19, (30) (31) (32) (33) (34) (35) (36) (37) (38) (39) (40) (41) (42) 46) . particularly, the participants were recruited by uk biobank in the period 2006-2010 (31) (32) (33) . this time lag by itself may produce a bias the results obtained in 2020, for any participant. during the 10-year period, there may be significant changes in the lifestyle and health factors associated with the vitamin d status of patients. moreover, the discrepancy between those and our results may be explained by a sample size of less than half in that study, the older population and the inability to control for several confounders, like ses and chronic medical conditions. according to our analysis, persons with covid-19-p were younger than non-infected ones. two-peak distributions for age groups were demonstrated to confer increased risk for covid-19: ages 25 years old and 50 years old ( figure 4 ). the first peak may be explained by high social gathering habits at the young age. the peak at age 50 years may be explained by continued social habits, in conjunction with various chronic diseases ( figure 4 ). other clinical characteristics that were significantly linked to the likelihood of covid-19 infection included male gender and low residential ses. despite its being discussed as a risk factor in prior publications (47) (48) (49) , obesity had not been significantly associated with either an increased risk for covid-19 infection or with hospitalization due to covid-19 in this study. surprisingly, chronic medical conditions, like dementia, cardiovascular disease, and chronic lung disease that were considered to be very risky in previous studies (50, 51) , were not found as increasing the rate of infection in our study. however, this finding is highly biased by the severe social contacts restrictions that were imposed on all the population and were even more emphasized in this highly vulnerable population. therefore, we assume that following the israeli ministry of health instructions, patients with chronic medical conditions significantly reduced their social contacts. this might indeed minimize the risk of covid-19 infection in that group of patients. the negative association with the current smoking status is unclear and this article is protected by copyright. all rights reserved should be investigated, since recent studies show conflicting data (36, (52) (53) (54) (55) (56) (57) (58) (59) (60) (61) (62) (63) . finally, in a subset analysis of only covid-19-p subjects, hospitalized patients were significantly older (58.69 vs. 46.88 years). multivariate analyses showed that being older than 50 years old was the single statistically significant risk factor for hospitalization. to conclude, the low plasma 25(oh)d levels almost doubled the risk for hospitalization due to the covid-19 infection in the israeli studied cohort. the main strength of the study is its being large, real-world, and population-based. an additional strength is the analysis of a multitude of variables that may affect the risk of covid-19 infection, independent of plasma 25(oh)d levels. however, the major weakness of the study is the retrospective database design. data regarding covid-19 symptoms and the hospitalization due to covid-19 infection, and also adverse clinical outcomes (for example, mechanical ventilation) will be further assessed. moreover, a possible selection bias arises in that vitamin d level was tested according to the presentation of symptoms, and not according to population-wide testing. however, our previous study showed that the health functional status cannot predict low 25(oh)d levels (45) . to conclude, our study found that suboptimal plasma vitamin d levels may be a potential risk factor for covid-19 infection, particularly, for the high hospitalization risks, independent of demographic characteristics and medical conditions. the finding is important, since it could guide healthcare systems in identifying populations at risk, and contribute to interventions aimed to reduce the risk of the covid-19 infection. more studies are required to assess the effects of vitamin d3 supplements on the risk of hospitalizations due to covid-19 infection. we conducted a population-based study utilizing data from the leumit health services (lhs) database, a large health maintenance organization in israel that provides services to around 730,000 members nationwide. the comprehensive computerized database of lhs is continuously updated with regard to demographics, medical visits, laboratory tests and hospitalizations. the validity of the diagnoses in the registry is high for important medical diagnoses and laboratory data (20) (21) (22) . the study period was from february 1 st to april 30 th 2020. the study population included all members of lhs who were tested for covid-19 infection during the study period and who had at least one previous test for plasma 25 according to lhs guidelines, blood was collected from fasting persons and transported on ice to the center laboratory for processing within 4 h of collection using diasorin chemiluminescence assay (24) (25) (26) (27) . data of each subject were collected from the lhs computerized database and included age, gender, socioeconomic status (ses), weight, height, body mass index, current smoking status, psychiatric and somatic comorbidities, and hospitalizations as a result of the covid-19 infection. all the somatic and psychiatric diagnoses were based on the international classification of disease, tenth revision (icd-10) codes and included chronic lung disorders (asthma, chronic obstructive pulmonary disease), diabetes, hypertension, depressive and anxiety disorders, schizophrenia and dementia. classifies all cities and towns into 20 subgroups of ses. the classifications of one to nine were considered as a low-medium ses, and ten to twenty were considered as medium-high ses. obesity was considered as bmi>30 m 2 /kg. osteoporosis foundation, the optimal 25(oh) d levels should be greater than 30 ng/ml (75 nmol/l), thus the plasma 25(oh)d level that is less than 30 ng/ml (75 nmol/l) were considered as suboptimal and referred as "low" in our study (28, 29) (table 1) . statistical analysis was conducted using stata 12 software (statacorp lp, college station, tx). the initial analysis compared demographic characteristics between individuals who tested positive (covid-19-p) and negative (covid-19-n) for covid-19. student's t-test and fischer's exact χ 2 test were used for continuous and categorical variables, respectively, based on a normal distribution (0,1) and variable characteristics. the categorical data were shown in counts and percentages. data on continuous variables with normal distribution were presented as means and 95% confidence intervals (cis). the assumptions were based on two-sided tests with α of 0.05. this article is protected by copyright. all rights reserved preliminary evaluation of risk estimates was conducted by stratified analyses. subsequently, multivariate logistic regression was used to estimate the odds ratios (or) and 95% ci for the independent association between low plasma 25(oh)d and a positive pcr test for the sars-cov-2 virus, while controlling for potential confounders. the association of low plasma 25(oh)d level with hospitalization due to covid-19 infection was assessed among those who tested positively for covid-19. open source programs, particularly, plotly r open source graphing library was used. plotly's r graphing library was used for the production of figures, including scatter plots, area charts, bar charts, and 3d charts. this article is protected by copyright. all rights reserved ethical considerations: this is a data-based study, and as such, has no clinical trial registration number. the study received approval from the leumit health services research committee and the shamir medical centre irb. the criterion for plasma vitamin d "sub-optimal" or "low" status was <30ng/ml. this article is protected by copyright. all rights reserved this article is protected by copyright. all rights reserved this article is protected by copyright. all rights reserved this article is protected by copyright. all rights reserved this article is protected by copyright. all rights reserved a new coronavirus associated with human respiratory disease in china the outbreak of coronavirus disease 2019 (covid-19)-an emerging global health threat epidemiology, causes, clinical manifestation and diagnosis, prevention and control of coronavirus disease (covid-19) during the early outbreak period: a scoping review coronavirus diseases (covid-19) 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trial in covid-19? med hypotheses accepted article this article is protected by copyright. all rights reserved 16 vitamin d and risk of cognitive decline in elderly persons obesity and overweight decreases the effect of vitamin d supplementation in adults: systematic review and meta-analysis of randomized controlled trials the vitamin d deficiency pandemic: approaches for diagnosis, treatment and prevention the role of vitamin d in the prevention of coronavirus disease 2019 infection and mortality assessment of the completeness and accuracy of computer medical records in four practices committed to recording data on computer prevalence of selected chronic diseases in israel the use of an automated patient registry to manage and monitor cardiovascular conditions and related outcomes in a large health organization comparative global epidemiological investigation of sars-cov-2 and sars-cov diseases using meta-mums tool through incidence, mortality, and recovery rates vitamin d status of 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countries south of latitude 35 degrees north supports vitamin d as a factor determining severity the association between obesity and poor outcome after covid-19 indicates a potential therapeutic role for montelukast obesity is a risk factor for greater covid-19 severity letter to the editor: obesity as a risk factor for greater severity of covid-19 in patients with metabolic associated fatty liver disease preliminary estimates of the prevalence of selected underlying health conditions among patients with coronavirus disease 2019 -united states the novel coronavirus disease (covid-19) threat for patients with cardiovascular disease and cancer 2020) prevalence, severity and mortality associated with copd and smoking in patients with covid-19: a rapid systematic review and meta-analysis tobacco smoking and covid-19 pandemic: old and new issues. a summary of the evidence from the scientific literature smoking-mediated upregulation of the androgen pathway leads to increased sars-cov-2 susceptibility covid-19 in patients with thoracic malignancies (teravolt): first results of an international, registry-based, cohort study active smoking and severity of coronavirus disease 2019 (covid-19): differences in measurement of variables could cause errors in the results sars-cov-2 covid-19 susceptibility and lung inflammatory storm by smoking and vaping reply to: "current smoking is not associated with covid-19 meta-analysis investigating the relationship between clinical features, outcomes, and severity of severe acute respiratory syndrome coronavirus 2 (sars-cov-2) pneumonia influence of the sars-cov-2 outbreak on the uptake of a popular smoking cessation app in uk smokers: interrupted time series analysis current smoking is not associated with covid-19 2020) covid-19 and smoking: is nicotine the hidden link? airways expression of sars-cov-2 receptor, ace2, and tmprss2 is lower in children than adults and increases with smoking and copd this article is protected by copyright. all rights reserved this article is protected by copyright. all rights reserved this article is protected by copyright. all rights reserved key: cord-103451-h7986yl9 authors: drodge, d. r.; budu-aggrey, a.; paternoster, l. title: causal analysis shows evidence of atopic dermatitis leading to an increase in vitamin d levels date: 2020-04-23 journal: nan doi: 10.1101/2020.04.22.20075077 sha: doc_id: 103451 cord_uid: h7986yl9 atopic dermatitis (ad) patients have been observed to have lower vitamin d levels. previous studies have found little evidence that vitamin d levels causally influence the risk of ad, but the reverse direction has not yet been investigated. here we used mendelian randomization to assess the causal relationship between ad and serum vitamin d levels, using genetic data from the most recent gwa studies of vitamin d and ad. there was little evidence for vitamin d levels causally influencing ad risk (odds per standard deviations increase in log-transformed vitamin d levels =1.233, 95% ci 0.927 to 1.639, p-value =0.150). however, genetic liability for ad raises serum vitamin d levels by 0.043 (95% ci 0.017 to 0.069) standard deviations per doubling of odds of disease (p-value =0.001). the ad-associated filaggrin (flg) mutation r501x appears to show a particularly strong relationship with vitamin d. however, the relationship between ad and vitamin d holds when r501x is omitted (0.018, 95% ci 0.004 to 0.031, p-value =0.008). we found evidence that ad is causally associated with an increase in serum vitamin d levels. whilst the ad-associated flg gene has a particularly strong relationship with vitamin d, other ad snps show a consistent direction of effect, suggesting that ad more generally influences serum vitamin d levels. atopic dermatitis (ad, eczema) is an inflammatory skin condition which typically presents as erythema, scaling and urticaria (weidinger and novak 2016). u.s. prevalence is of the order of 10%, higher in children than adults (drucker et al. 2017) . moderate and severe disease imposes a functional and psychological burden on sufferers, as well as the risk of complications such as bacterial superinfection, eczema herpeticum and erythroderma. treatments currently follow several strategies: restoration of barrier function through topical emollients, reduction of inflammation through . cc-by 4.0 international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted april 23, 2020 . . https://doi.org/10.1101 /2020 immunomodulatory agents, and second-line treatments including phototherapy (rodenbeck et al. 2016) . a treatment of ongoing controversy is vitamin d supplementation -the most recent cochrane review concluded no benefit and warned of toxic effects of high doses (bath-hextall et al. 2012 ), but a more recently-performed meta-analysis found a reduction in scorad in patients receiving supplementation (hattangdi-haridas et al. 2019 ). ad and vitamin d have been linked in observational studies: sufferers have reduced levels of the hormone, more clearly so in children, and some evidence exists that deficiency is more marked in severe disease (palmer 2015) . vitamin d plays a role in calcium and phosphate homeostasis, and its deficiency has also been implicated in a variety of immunological disease states (rosen et al. 2012) . it derives from cholecalciferol, a steroid converted from the cholesterol precursor 7-dehydrocholesterol in the skin, under the action of ultraviolet radiation. hydroxylation in the liver produces 25hydroxycholecalciferol (vitamin d; 25-ohd), which the kidneys convert to an active form, 1,25dihydroxycolecalciferol (1,25-ohd). in questions of aetiology and causality, mendelian randomization (mr) can be of use. it allows causal inference to be drawn from population data, namely genome-wide association studies (gwas) (budu-aggrey and paternoster 2019). to assess the effect of an exposure on an outcome, mr uses exposure-associated single nucleotide polymorphisms (snps) as a proxy for the exposure of interest. these mutations are randomised at conception, thus limiting the influence of confounders on the allocation of exposure. mr is analogous to a randomised controlled trial without the cost and ethical difficulty of assigning disease states or known toxic environmental factors as exposures. the key underlying assumption is that each snp we use in this way acts on the outcome only through its upstream action on the exposurethis is violated if it affects it, whether directly or through an alternative pathway. manousaki and colleagues previously used mr to ascertain whether there was any evidence that vitamin d levels causally influenced ad, using a two sample mr method, with 25-ohd levels gwas data from the sunlight consortium , and the ad gwas data from the eagle consortium . cc-by 4.0 international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. (which was not certified by peer review) the copyright holder for this preprint this version posted april 23, 2020. . https://doi.org/10. 1101/2020.04.22.20075077 doi: medrxiv preprint (manousaki et al. 2017 ). here we extend this analysis using a recently published larger vitamin d gwas meta-analysis, which includes 401,460 uk biobank participants (manousaki et al. 2020) . we also include an investigation of the inverse causal direction, i.e. whether there is any evidence that genetic risk of ad causally influences vitamin d. mr analyses of ad and 25-ohd are shown in table 1 : change in serum 25-ohd level is presented log-transformed, normalised to zero mean with unit standard deviation, consistent with the units used by manousaki. there was little evidence for vitamin d levels causally influencing the risk of ad (odds ratio per sd change in log-transformed 25-ohd levels = 1.233, 95% ci 0.927 to 1.639, p-value =0.150), a finding in keeping with the 2017 analysis which found an effect size of 1.12, (95% ci 0.92 to1.37, p-value =0.270) (manousaki et al. 2017 ). however, we did find evidence for ad causally increasing vitamin d levelsan effect of 0.043 sd increase in log-transformed 25-ohd concentration per doubling odds of ad (95% ci 0.017 to 0.069, p-value =0.001). is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted april 23, 2020. . tests of validity of this analysis were performed, which found strong evidence of heterogeneity (cochran q =282, p-value < 2.2x10 -16 ) and horizontal pleiotropy (egger intercept = -0.012; 95% ci= -0.018 to -0.006; p-value=5.4x10 -4 ) ( figure s1 ). a substantial contribution to this appeared to be the particularly strong result from one snp, r501x (rs61816761), a functional mutation in the flg region ( figure s2 ). other functional flg mutations are known and so we further examined the association between the 4 most common of these (r501x[rs61816761], 2282del4 [rs41370446], r2447x [rs138726443], and s3247x [rs150597413]) and vitamin d from the gwas. all except 2282del4 were available in the vitamin d gwas and found to be strongly associated with 25-ohd levels ( figure s3 ). to investigate whether the causal relationship was driven entirely by the flg region we repeated the mr omitting this locus. the effect estimate was smaller, but still gave evidence of causality: 0.018 (0.004 to 0.031, p-value= 0.008) (table 1, figure 1 ). sensitivity analyses found less evidence of heterogeneity when excluding the flg locus from the ad instrument (cochran's q=60, p-value=2.3x10 -5 ) and little evidence of horizontal pleiotropy (egger intercept = 0.001; 95% ci= -0.005 to 0.006; p-value=0.782) ( figure s4 ). to explore whether this causal relationship is limited to ad, or whether inflammatory disease per se might confer any change in vitamin d levels, additional mr analyses were carried out for other . cc-by 4.0 international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted april 23, 2020. we found evidence that (i) ad causes an increase in vitamin d levels, (ii) although the filaggrin locus has a strong influence on this, a causal effect is still seen when omitting this locus; and (iii) no similar magnitude and direction of effect is seen in other atopic and autoinflammatory diseases. . cc-by 4.0 international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted april 23, 2020. . https://doi.org/10. 1101 /2020 we confirm that there is little evidence that vitamin d causally influences ad, as has previously been reported (manousaki et al. 2017 ), but find evidence, from the reverse direction mendelian randomization analysis, that genetic risk of ad causally increases vitamin d levels. this relationship is opposite to what has been reported observationally, where ad patients are seen to have lower vitamin d (palmer 2015) . it thus undermines the rationale for using vitamin d supplementation as a therapy for ad. when causal estimates are opposite to those reported observationally, it is likely that this is due to the confounding structure masking the true nature of the relationship in the observational estimates. confounders that have opposing effects on vitamin d and ad, that might explain this phenomenon include obesity, ses, pollution and latitude (mesquita et al. 2013 ). in any case, our current study provides further evidence that raising vitamin d is unlikely to be an effective treatment for ad. (rs41370446), r2447x (rs138726443), and s3247x (rs150597413). we were able to test the association between vitamin d and r501x, r2447x and s3247x and found >0.1sd change in 25-ohd per mutation at each of these sites. the fact that we observed substantial heterogeneity and evidence of horizontal pleiotropy when we included the flg locus in our ad instrument (which reduced substantially when this locus was removed), suggests that flg has a direct influence on vitamin d, that bypasses ad. a link between flg and vitamin d has been previously reported in the same direction that we report here (thyssen et al. 2012) . they sought to explain this with a uvb-vitd3 hypthosis, whereby trans-urocanic acid (uca), a breakdown product of filaggrin (generated when histidase metabolises histidine in filaggrin), provides epidermal protection against uvb (mildner et al. 2010) . therefore, inheriting a flg-null mutation (particularly one which reduces histidine in filaggrini.e. the r501x truncation reduces flg from 413 to 35 histidine residues . cc-by 4.0 international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted april 23, 2020 . . https://doi.org/10.1101 /2020 (fauman 2020)) would result in increased uv absorption and increased vitamin d3 synthesis. it has been further proposed that such a mechanism might be advantageous in northern latitudes and is one explanation as to why a latitude-dependent gradient of flg mutation frequency is observed (thyssen and elias 2017) . given, this strong relationship between flg mutations and increased vitamin d, it would be sensible in future clinical trials of supplementation or phototherapy to investigate whether different effects are observed in ad patients with and without flg mutations. in addition to the flg-vitamin d direct link, there also appears to be a general influence of ad on vitamin d, as evidenced by the causal effect observed after omitting the flg locus from the ad instrument. it is unclear what the mechanism for this might be, whether there are other biological effects in the skin, similar to that seen for flg, or whether there are behavioural mechanisms by which suffering from ad may in turn alter uv and/or vitamin d exposure. we also need to consider whether the vitamin d gwas (from which our data were taken) included people with ad whose vitamin d status was raised because they were using vitamin d raising therapy. the study did adjust for vitamin d supplementation (manousaki et al. 2020 ) and although phototherapy was not specifically commented on, the uk biobank website showcase summary reports that only 69 of 410,256 subjects are coded as receiving some form of phototherapy (operative procedures opcs4, skin, phototherapy s12) (uk biobank)if accurate and complete, this translates to a small proportion within the vitamin d gwas and is unlikely to explain our findings. in this study we confirm that there is little evidence that vitamin d causally influences ad. however, we did find evidence to suggest that the genetic risk of ad causally increases serum vitamin d levels, both through the direct effect of the flg gene on vitamin d, and also through additional, likely more general, mechanisms. our findings suggest that vitamin d supplementation as a treatment for ad is not supported, moreover that further investigation into the relationship between ad and vitamin d is warranted to determine the mechanisms of the reported causal relationship and suggest stratifying future vitamin d and phototherapy trials and epidemiological analyses by flg status to be able to better evaluate the contribution of different mechanisms. . cc-by 4.0 international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted april 23, 2020. . https://doi.org/10. 1101 /2020 to investigate the causal effect of genetically predicted vitamin d levels upon ad risk, a genetic instrument for 25-ohd levels was derived from snps reported to be most strongly associated (pvalue < 5x10 -8 ) in the most current gwa study by manousaki and colleagues (n=443,734) (manousaki et al. 2020) (table s1 ). snp-association estimates were presented for standardized logtransformed 25-ohd levels. a total of 59 independent snps (r 2 threshold = 0.001) were identified using the twosamplemr r package clumping tool (table s2 ). full summary data was also made available by the authors to allow for mr analyses with vitamin d as the outcome. to investigate the causal effect of ad genetic liability upon vitamin d levels, an ad genetic instrument was derived from the most current gwas by the eagle consortium (paternoster et al. 2015) , where 24 loci were reported to be most strongly associated with ad (p<5x10 -8 ) (table s1 & s3). the index snp from each gwas locus was selected (except for 1q21.3, where the known functional variant rs6181671 replaced the index gwas snp rs61813875). effect estimates were available for 18,900 cases and 84,166 controls of white european ancestry. ad gwas summary statistics (with 23andme participants excluded) was also made available (10,788 cases, 30,047 controls). the genetic liability of additional inflammatory diseases upon vitamin d levels was also investigated. in doing so, published gwas data was used to derive genetic instruments for asthma (demenais et al. 2018) , rheumatoid arthritis (okada et al. 2014) , systemic lupus erythematosus (bentham et al. 2015 ), psoriasis (tsoi et al. 2017 , type 1 diabetes mellitus (onengut-gumuscu et al. 2015) , multiple sclerosis (beecham et al. 2013 ), crohn's disease and ulcerative colitis (de lange et al. 2017) using snps reported to be most strongly associated (p-value < 5.0x10 -8 ) (table s1 ; s4 to s11). snp estimates were derived from individuals of white european ancestry. given the overlapping risk variants for ad and asthma, the asthma instrument was filtered to exclude snps with nominal association with ad (p<0.05). . cc-by 4.0 international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted april 23, 2020. . two-sample mr was performed to investigate the casual relationship between ad and genetically predicted vitamin d levels using the twosamplemr package in r. our genetic instrument for vitamin d levels was used to assess the causal effect upon ad risk using summary gwas data from the most recent ad gwas meta-analysis (paternoster et al. 2015) . likewise, in the reverse direction, the ad genetic instrument defined was used to estimate the causal effect of ad genetic risk upon vitamin d levels (sd change in log 25-ohd levels) using summary gwas data from the recent vitamin d gwas (manousaki et al. 2020 ). this was also performed with the additional inflammatory instruments created to estimate the causal effect of each trait upon vitamin d levels. as the gwas data for ad and inflammatory traits did not include uk biobank participants, there was no sample overlap in the mr analyses performed. a causal estimate was obtained by applying the inverse-variance weighting (ivw) method, where the snp-exposure and snp-outcome associations were combined in a meta-analysis assuming multiplicative random effects. when presenting the causal effect upon vitamin d levels, causal estimates were multiplied by 0.693 to represent the sd change in log 25-ohd levels per doubling odds of ad (or inflammatory trait) genetic risk, as previously demonstrated (gage et al. 2017) . mr-egger regression, weighted median analysis and the weighted mode-based estimate (mbe) were performed to investigate potential horizontal pleiotropy. snps found to influence the exposure and the outcome through different pathways could bias the causal estimate and violate the mr assumption that genetic instruments only have an effect on the outcome via the exposure investigated (budu-aggrey and paternoster 2019). mr-egger regression provides a valid causal estimate under the 'inside' assumption, where each snp-exposure effect is uncorrelated with the horizontal pleiotropic effect of the snp. the intercept also allows the size of a pleiotropic effect to be determined (bowden et al. 2015) . the weighted median method provides a valid causal estimate if at least 50% of the information in the mr analysis comes from valid instruments (bowden et al. 2016) , and the weighted mbe provides a valid causal estimate assuming that the most frequent pleiotropy value is zero across the genetic instruments (hartwig et al. 2017) . we also characterised heterogeneity using cochran's q . cc-by 4.0 international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. (which was not certified by peer review) the copyright holder for this preprint this version posted april 23, 2020. . statistic, which can indicate invalid instruments that are present due to the occurrence of pleiotropy (bowden et al. 2018 ). all analyses were carried out in r (www.r-project.org) unless otherwise stated. the code used to carry out these analyses is available on github (https://github.com/abuduaggrey/atopic_dermatitis_25ohd_mr). datasets related to this article can be found at https://github.com/abuduaggrey/atopic_dermatitis_25ohd_mr. summary gwas data for vitamin d (25-ohd) levels was made available by the authors upon request (manousaki et al. 2020 ). lp has received personal fees from merck for scientific input engagement related to mr methodology. dietary supplements for established atopic eczema analysis of immune-related loci identifies 48 new susceptibility variants for multiple sclerosis genetic association analyses implicate aberrant regulation of innate and adaptive immunity genes in the pathogenesis of systemic lupus erythematosus mendelian randomization with invalid instruments: effect estimation and bias detection through egger regression consistent estimation in mendelian randomization with some invalid instruments using a weighted median estimator invited commentary: detecting individual and global horizontal pleiotropy in mendelian randomization-a job for the humble heterogeneity statistic? research techniques made simple: using genetic variants for randomization multiancestry association study identifies new asthma risk loci that colocalize with immune cell enhancer marks the burden of atopic dermatitis: summary of a report for the national eczema association no flg->no his->no urocanate->more uv radiation->more cholecalciferol production->more vitamin d investigating causality in associations between smoking initiation and schizophrenia using mendelian randomization. sci. rep robust inference in summary data mendelian randomization via the zero modal pleiotropy assumption vitamin d deficiency and effects of vitamin d supplementation on disease severity in patients with atopic dermatitis: a systematic review and meta-analysis in adults and children the mr-base platform supports systematic causal inference across the human phenome. elife genome-wide association study implicates immune activation of multiple integrin genes in inflammatory bowel disease genomewide association study for vitamin d levels reveals 69 independent loci vitamin d levels and susceptibility to asthma, elevated immunoglobulin e levels, and atopic dermatitis: a mendelian randomization study atopic dermatitis and vitamin d: facts and controversies knockdown of filaggrin impairs diffusion barrier function and increases uv sensitivity in a human skin model genetics of rheumatoid arthritis contributes to biology and drug discovery fine mapping of type 1 diabetes susceptibility loci and evidence for colocalization of causal variants with lymphoid gene enhancers vitamin d and the development of atopic eczema multi-ancestry genome-wide association study of 21,000 cases and 95,000 controls identifies new risk loci for atopic dermatitis phototherapy for atopic dermatitis the nonskeletal effects of vitamin d: an endocrine society scientific statement it remains unknown whether filaggrin gene mutations evolved to increase cutaneous synthesis of vitamin d skin barrier abnormality caused by filaggrin (flg) mutations is associated with increased serum key: cord-255233-rvgj6pvk authors: munday, molly-rose; rodricks, rohan; fitzpatrick, michael; flood, victoria m.; gunton, jenny e. title: a pilot study examining vitamin c levels in periodontal patients date: 2020-07-28 journal: nutrients doi: 10.3390/nu12082255 sha: doc_id: 255233 cord_uid: rvgj6pvk background: periodontal disease is the leading cause of tooth loss worldwide. current periodontal treatment is limited by its dependency on patients learning and maintaining good dental habits, and repeated visits to oral health physicians. vitamin c’s role in collagen synthesis and immune function makes it important in wound healing and possibly periodontal healing. therefore, if some patients are deficient, this may worsen patient outcomes. methods: patients were invited to participate following assessment and treatment at the westmead centre of oral health periodontic clinic, regardless of current disease stage or treatment. adults were eligible if they gave informed consent and had current periodontal disease. study involvement consisted of periodontal assessment and care followed by an interview and measurement of serum vitamin c and c-reactive protein (crp). results: a total of 6 out of 20 patients had vitamin c levels less than the institutional normal range, of whom 2 had levels <11.4 μmol/l and one <28 μmol/l. low vitamin c was associated with higher periodontal disease stage (p = 0.03). elevated crp was found in 2/3 of people with low vitamin c and crp was negatively correlated with vitamin c (p < 0.01). vitamin c did not correlate with patient-reported fruit or vegetable consumption, but high processed meat intake was associated with lower vitamin c. conclusion: although a small study, this rate of vitamin c deficiency in the periodontal clinic is clinically important and correlations with disease severity and crp suggests biological importance. this warrants further studies to assess vitamin c and whether supplementation improves periodontal outcomes, particularly in deficient subjects. vitamin c (ascorbic acid) is an essential nutrient involved in a range of bodily processes such as immune function, metabolism and production of structurally sound collagen. unlike other animals, humans, primates, guinea pigs and bats rely on nutritional sources such as citrus fruit, kiwi, tomatoes, broccoli and capsicum (bell peppers) for vitamin c because they lack the enzyme required for its nutrients 2020, 12, 2255 2 of 9 synthesis, l-gulono-gamma-lactone oxidase (glo) [1] . historically, low availability of fresh fruits and vegetables led to widespread deficiency. severe vitamin c deficiency manifests as scurvy [2] . symptoms of scurvy include bleeding gums, tooth loss, nausea, fatigue, eventual wound re-opening, infections, fractures, haemorrhages, delirium and death [3] . thought to be long eliminated, scurvy has begun to re-emerge in modern populations [2, 4, 5] . clinically, vitamin c status is usually assessed by measuring serum or plasma vitamin c levels. blood levels correlate best with recent vitamin c intake, usually over days, except in the setting of recent supplementation. commonly, serum vitamin c analysis is used in conjunction with questions about dietary intake of fruits and vegetables. periodontal disease is an umbrella term for a range of conditions affecting the periodontium. it is the result of chronic bacterial plaque build-up and inflammation resulting in damage to the underlying gingiva and alveolar bone [6] [7] [8] . periodontitis is "a chronic multi-factorial chronic inflammatory disease associated with dysbiotic plaque biofilms and characterised by progressive destruction of the tooth-supporting apparatus" [9] . this leads to destruction of the alveolar bone, recession of the gums, and, if untreated, eventual tooth loss which is seen in stage 4 disease [10] . the 2017 american academy of periodontology classification system formally incorporates clinical attachment loss around teeth, radiographical bone loss, tooth loss, probing depth, bleeding on probing, disease progression and presence of systemic diseases. at initial assessment the patient is assigned a stage and grade based on the above consensus guidelines [11] . in brief, stage 1 is the border between simple gingivitis and periodontitis and is associated with early stages of attachment loss. stage 2 is moderate periodontitis with damage to tooth support. stage 3 is present when there is significant damage to the attachment apparatus of teeth and tooth loss can occur without treatment. stage 4 is considerable damage to tooth support, often accompanied by tooth loss and difficulty with chewing of food. grade relates to "evidence or risk of rapid progression, anticipated treatment response, and effects on systemic health" [11] and is rated a, b or c, with c the most severe. usual treatment involves removal of plaque and calculus deposits, sometimes in conjunction with systemic or local antibiotics and encouraging the patient to improve their daily oral hygiene practices [11] . current periodontal treatments are effective but can be limited by their dependency on patients taking up and maintaining good dental habits. periodontal disease is a common chronic dental disorder that presents a large burden on both local and global societies. together, gingivitis and periodontitis are estimated to occur in 43% of the australian population, [12] and 47% of the us population [13] , and severe periodontal disease is thought to affect more than 10% of the global population. likely due to its inflammatory involvement, it is more common alongside a range of comorbidities including cardiovascular diseases, rheumatoid arthritis, and type 2 diabetes [14] . past studies have examined vitamin c in dental patients with mild to severe gingivitis and this has been recently reviewed [3] . overall, vitamin c levels were lower in people with gingivitis. additionally, patients report decreased bleeding and gingival inflammation when supplemented with vitamin c [15] . an inverse relationship has also been established between the severity of necrotizing, ulcerative gingivitis and vitamin c plasma levels [16] . this is thought to be due to impaired collagen synthesis [17, 18] . therefore, vitamin c deficiency results in decreased healing capacity [19] [20] [21] . a number of studies such as woelber et al. have also reported the benefits of a high quality diet for reducing gingival and periodontal inflammation [22] . reduced bleeding was also noted when dental patients were given two grapefruits a day [23] . vitamin c deficiency is more common in smokers, the elderly and people of lower socio-economic status, potentially putting those groups at increased risk of periodontal diseases [24, 25] . this study aimed to examine the prevalence of vitamin c deficiency within an australian periodontal population. we hypothesised that there would be a clinically important prevalence of vitamin c deficiency, and we tested whether simple dietary questions could predict deficiency. the background rate of deficiency in the australian population is unknown, as is the deficiency rate in the periodontal disease population. as such, this study examined vitamin c levels in a periodontal clinic population. this study was approved by the western sydney local health district human research ethics committee. all subjects gave informed, written consent. hrec reference number 5127-2019/eth02304. patients were eligible to participate in this study if they were an adult attending the westmead centre of oral health (wcoh) periodontic clinic. additional eligibility criteria included being able to give informed, written consent and the ability to speak and understand english (7 patients were excluded for this). further details can be found in the patient recruitment diagram (figure 1 ). patients were approached following their consultation and/or treatment at the periodontal clinic. three patients declined to consent upon learning that a blood test would be required. the rest were given study details and 9 declined consent at this stage. 2019/eth02304. patients were eligible to participate in this study if they were an adult attending the westmead centre of oral health (wcoh) periodontic clinic. additional eligibility criteria included being able to give informed, written consent and the ability to speak and understand english (7 patients were excluded for this). further details can be found in the patient recruitment diagram ( figure 1 ). patients were approached following their consultation and/or treatment at the periodontal clinic. three patients declined to consent upon learning that a blood test would be required. the rest were given study details and 9 declined consent at this stage. consenting patients were asked about their dietary intake using a survey created by vf and jg. they then underwent a venepuncture to measure serum vitamin c and c-reactive protein (crp) levels. blood samples were collected, immediately wrapped in foil and placed on ice. these instructions were written on the collection request forms. as above, dental examination and assigning of stage and grade was conducted prior to study recruitment. using a williams periodontal probe, six-point probing depth measurements as well as gingival recession measurements (both in millimeters) around each existing tooth were carried out for every patient. missing teeth, tooth mobility and presence of furcations were marked. every patient received a panoramic radiograph to assess for current alveolar bone levels around the existing dentition. radiographic bone loss around teeth was assessed as being in the coronal third, extending to the mid third of the root or beyond (up to the apex of the tooth). the amount and distribution of supra-and subgingival plaque and calculus deposits was noted as well as the presence of bleeding and/or suppuration on gingival probing. additional data were collected from the patients' medical records including their age, address, smoking status and other medical disorders which were confirmed during the interview. the strobe checklist for cross-sectional studies was used. hypertension and hyperlipidaemia were assessed as present in patients who were receiving antihypertensives or lipid-lowering agents, respectively. residential addresses were used with the 'socio-economic indexes for australia 2016' to estimate ses (socioeconomic score) [26] . consenting patients were asked about their dietary intake using a survey created by vf and jg. they then underwent a venepuncture to measure serum vitamin c and c-reactive protein (crp) levels. blood samples were collected, immediately wrapped in foil and placed on ice. these instructions were written on the collection request forms. as above, dental examination and assigning of stage and grade was conducted prior to study recruitment. using a williams periodontal probe, six-point probing depth measurements as well as gingival recession measurements (both in millimeters) around each existing tooth were carried out for every patient. missing teeth, tooth mobility and presence of furcations were marked. every patient received a panoramic radiograph to assess for current alveolar bone levels around the existing dentition. radiographic bone loss around teeth was assessed as being in the coronal third, extending to the mid third of the root or beyond (up to the apex of the tooth). the amount and distribution of supra-and subgingival plaque and calculus deposits was noted as well as the presence of bleeding and/or suppuration on gingival probing. additional data were collected from the patients' medical records including their age, address, smoking status and other medical disorders which were confirmed during the interview. the strobe checklist for cross-sectional studies was used. hypertension and hyperlipidaemia were assessed as present in patients who were receiving antihypertensives or lipid-lowering agents, respectively. residential addresses were used with the 'socio-economic indexes for australia 2016' to estimate ses (socioeconomic score) [26] . serum vitamin c was analysed using hydrophilic interaction chromatography (hilic) conducted at new south wales health pathology, royal prince alfred hospital (rpah). hilic is more suitable for polar molecules such as vitamin c with good retention and separation rates. in order to increase sample stability, 100 µl of each patient sample was diluted with 100 µl of internal standard containing antioxidant tris(2-carboxylethyl)phosphine hydrochloride (tcep, sigma-aldrich, sydney, australia). samples were filtered through a 10 kda centrifugal protein removal column then centrifuged for 30 min. next, 100 µl acetonitrile (sigma-aldrich) was added to 100 µl of the supernatant, then the sample was vortexed and transferred into an hplc vial for analysis. analysis used the dionex ultimate 3000 uhplc with dad (thermo fisher scientific cat # 6765015, waltham, ma, usa). the assay's detection limit was 5µmol/l, with the normal range being 40-100 µmol/l. this was set by testing a normal group and aligns with the normal range at monash health in australia. ascorbic acid measurements were linear over an analytical range of 5-250 µmol/l. the within batch imprecision was <3% and the between batch imprecision <7%. recovery was over 90% for the analyte and its internal standards. crp was measured using rate nephelometry by nsw health pathology at westmead hospital institute of clinical pathology and medical research (icpmr). crp levels when normal are reported as <4 µmol/l, so those patients were assigned a result of 3 µmol/l. statistical analysis was undertaken using graphpad prism version 8 (san diego, ca, usa) or spss version 21 (ibm, chicago, il, usa). where the data was not normally distributed (shapiro-wilk p-value < 0.05), non-parametric testing such as independent sample mann-whitney u hypothesis testing or spearman's correlation tests were undertaken. a p-value of <0.05 was considered statistically significant. data is shown as mean ± standard deviation or where not normally distributed median (95% confidence interval). patient demographics are reported in table 1 . twenty patients were recruited before the dental clinic was shut down due to covid-19. a number of comorbid conditions were reported including cardiovascular diseases, diabetes mellitus, crohn's disease and thyroid issues. patients were approached regardless of their progression through treatment, or their severity of periodontal disease. most patients were approached after their initial examination (n = 12), or during the early stages of treatment (n = 5). information was obtained from patient records and/or dietary survey. * socioeconomic score (ses) was calculated based using the patient's address [26] . 1000 is the australian median. data shows mean±standard deviation or median (95% ci). nutrients 2020, 12, 2255 5 of 9 the patients were recruited after review by the treating dentist and before collection of diet information or blood tests so scores were not influenced by diet history or blood results. the 2017 world workshop consensus guidelines (published in 2018) were used to grade disease severity [11] . the patients in this study had clinically important periodontal disease; 9 of 20 patients were stage 3, grade b or c indicating advanced periodontal deterioration. nine more patients were stage 4, grade b or c ( table 2 ). five patients had elevated crp levels of >4 μmol/l. one of these was a patient with known crohn's disease whose level was 32 μmol/l, so their crp result was excluded from further analysis. four people with low vitamin c had elevated crp levels (figures 3a, 3b) . vitamin c and crp were significantly inversely correlated producing a r 2 -value of 0.81 (spearman's correlation test) and a two tailed p-value of 0.0016 (figure 3b ). people consuming the estimated average requirement of dietary vitamin c or more have levels of 38 µmol/l or higher [27] . however, most other centers use cut-offs of 28 µmol/l for insufficiency and 11.4 µmol/l for deficiency. by these criteria, 2 patients are deficient and 1 has insufficiency. three patients below our normal range would be classified as having adequate status with levels of 29, 29 and 38 respectively. alternately, a recent review paper suggests an adequate vitamin c for periodontal patients is 56.8 µmol/l [3] . if this is examined, 9 people had vitamin c under that level. five patients had elevated crp levels of >4 µmol/l. one of these was a patient with known crohn's disease whose level was 32 µmol/l, so their crp result was excluded from further analysis. four people with low vitamin c had elevated crp levels (figure 3a,b) . vitamin c and crp were significantly inversely correlated producing a r 2 -value of 0.81 (spearman's correlation test) and a two tailed p-value of 0.0016 (figure 3b ). the shaded area indicates results below the assay normal range. one patient returned a serum vitamin c of 40 μmol/l (normal 40 -100 μmol/l) and was classified as normal. (b) periodontal stage was evaluated by the treating dentist (rr) prior to blood collection for vitamin c. symbol fill colour indicates grade of periodontal disease (a = green, b = yellow, c = red).* = p = 0.03. five patients had elevated crp levels of >4 μmol/l. one of these was a patient with known crohn's disease whose level was 32 μmol/l, so their crp result was excluded from further analysis. four people with low vitamin c had elevated crp levels (figures 3a, 3b) . vitamin c and crp were significantly inversely correlated producing a r 2 -value of 0.81 (spearman's correlation test) and a two tailed p-value of 0.0016 (figure 3b) . patients each had an interview about their dietary habits around fruit and vegetable intake to see whether this could predict serum vitamin c. people with vitamin c deficiency reported a nonsignificant higher weekly intake of servings of fruits (median 14 (2-21) versus 7 (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) in people without deficiency) and no decrease in vegetable intake (median 12 (4-21) versus 12 (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) in people without deficiency). interestingly, people with vitamin c <40 μmol/l reported higher weekly servings of processed meat (4 versus 0.6, p = 0.024). patients each had an interview about their dietary habits around fruit and vegetable intake to see whether this could predict serum vitamin c. people with vitamin c deficiency reported a non-significant higher weekly intake of servings of fruits (median 14 (2-21) versus 7 (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) in people without deficiency) and no decrease in vegetable intake (median 12 (4-21) versus 12 (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) in people without deficiency). interestingly, people with vitamin c < 40 µmol/l reported higher weekly servings of processed meat (4 versus 0.6, p = 0.024). using the home address for each subject, socioeconomic status (ses) was estimated as described in methods. median ses did not differ between deficient and non-deficient groups with wide confidence intervals (median in replete group 987 (929-1094) and in deficient group 1000 (868-1045)). ses also did not differ between stage 4 and stage 2/3 patients (ses medians 990 and 991, respectively). this study reports that a significant proportion of patients attending the periodontics clinic at the westmead centre of oral health have vitamin c deficiency. although a small sample size, 6 of 20 people having results below the normal range is a startling statistic that warrants further research. patients with low vitamin c were notified of their test results, and 500 mg per day of vitamin c was recommended. when considered in the context of scurvy, periodontal disease shares a number of similarities such as excessive gum bleeding and tooth loss, therefore it is likely that some periodontal patients meet the requirements for scurvy diagnosis. because low vitamin c correlated with more advanced periodontal disease and with increased crp, a measure of systemic inflammation, it is likely that this finding is biologically important. crp is recognised to be elevated in some patients with periodontal disease, and in those people, treatment is associated with lowering of crp [28]. the next step may be to conduct a randomised placebo-controlled trial, with the hypothesis that vitamin c will assist periodontal healing in people who are deficient. if whole-body vitamin c status is adequate, then it seems unlikely that supplementation would benefit that particular individual. additionally, as our dental service sees tertiary referral cases, the deficiency proportion in our patients is likely to be more severe than seen in normal dental practices. therefore, studies in community-based dental clinics in australia and other countries are also of interest. however, it is worth noting that the 3 in 10 rate of results below the normal range rate in this study is lower than seen in our high-risk foot ulcer clinic patients (50%, unpublished data). although research has been conducted concerning the relationship between vitamin c and periodontal disease, there is a lack of studies examining the prevalence of vitamin c deficiencies within the australian periodontal population and general australian population. this study provides pilot data for the prevalence of such deficiencies. there are a number of limitations to this study, the most obvious being sample size. study recruitment had to be halted when the dental clinic was closed due to covid-19. secondly, recruitment was limited to the wcoh periodontic clinic and non-tertiary centres may find lower deficiency rates. thirdly, as this was a cross-sectional study, it was not able to assess whether deficiency affected periodontal healing, or whether treatment improved healing. additionally, the short survey of diet may be an imprecise indicator of vitamin c intake, and a different screen of diet (such as 24 h recalls) may provide further insights into the association of dietary intake and vitamin c status [29]. in conclusion, vitamin c deficiency was prevalent at an unacceptable rate in our periodontal clinic. deficiency correlated with more severe periodontal disease, and with increased systemic inflammation. we recommend consideration of testing of vitamin c for patients with significant periodontal disease, particularly if other features of scurvy are present such as bruising or corkscrew hairs, or if periodontal healing does not progress as expected. further research should be conducted into the relationships between vitamin c and periodontal disease, and a randomised, controlled trial would be ideal. the authors declare that they have no relevant conflict of interest. inactivation dates of the human and guinea pig vitamin c genes old sailors" illness makes a return. oral surg. oral med. oral pathol. oral radiol. 2019, 128, e88 vitamin c and its role in periodontal diseases-the past and the present: a narrative review an unconventional case of scurvy scurvy: a rare case in an adult classification and diagnosis of aggressive periodontitis impact of the global burden of periodontal diseases on health, nutrition and wellbeing of mankind: a call for global action nutrition, inflammation, and periodontal disease consensus report of workgroup 2 of the 2017 world workshop on the classification of periodontal and peri-implant diseases and conditions mean annual attachment, bone level, and tooth loss: a systematic review staging and grading of periodontitis: framework and proposal of a new classification and case definition australian research centre for population oral health. periodontal diseases in the australian adult population prevalence of periodontitis in adults in the united states: 2009 and 2010 comorbidity of periodontal disease: two sides of the same coin? an introduction for the clinician the effect of controlled ascorbic acid depletion and supplementation on periodontal health a case-control study of plasma ascorbate and acute necrotizing ulcerative gingivitis collagen structure and stability regulation of collagen synthesis by ascorbic acid vitamin c: the known and the unknown and goldilocks plasma and urinary ascorbic acid leveles in the postoperative period role in oral tissue: a review an oral health optimized diet can reduce gingival and periodontal inflammation in humans-a randomized controlled pilot study grapefruit consumption improves vitamin c status in periodontitis patients prevalence and risk factors for vitamin c deficiency in north and south india: a two centre population based study in people aged 60 years and over estimated prevalence and predictors of vitamin c deficiency within uk's low-income population socio-economic indexes for areas (seifa) dietary reference intakes for vitamin c, vitamin e, selenium, and carotenoids key: cord-317265-n6x0r58i authors: singh, varsha title: can vitamins, as epigenetic modifiers, enhance immunity in covid-19 patients with non-communicable disease? date: 2020-07-13 journal: curr nutr rep doi: 10.1007/s13668-020-00330-4 sha: doc_id: 317265 cord_uid: n6x0r58i purpose of review: the highly infectious transmissible disease, the novel sars-cov-2, causing the coronavirus disease (covid-19), has a median incubation time of 5 to 15 days. the symptoms vary from person to person and many are “hidden carriers.” few people experience immediate reaction and even death within 48 h of infection. however, many show mild to chronic symptoms and recover. nevertheless, the death rate due to covid-19 transmission is high especially among patients with non-communicable diseases. the purpose of this review is to provide evidence to consider vitamins as epigenetic modifiers to enhance immunity and reduce inflammatory response in covid-19 patients with non-communicable diseases. recent findings: clinical evidence has suggested the risk of getting infected is high among individuals with non-communicable diseases such as cardiovascular disease, type-2 diabetes, cancer, acute respiratory distress syndrome, and renal disease, as well as the elderly with high mortality rate among the cohort. the impact is due to an already compromised immune system of patients. every patient has a different response to covid-19, which shows that the ability to combat the deadly virus varies individually. thus, treatment can be personalized and adjusted to help protect and combat covid-19 infections, especially in individuals with non-communicable diseases. summary: based on current published scientific and medical evidence, the suggestions made in this article for combination of vitamin therapy as epigenetic modifiers to control the unregulated inflammatory and cytokine marker expressions, further needs to be clinically proven. future research and clinical trials can apply the suggestions given in this article to support metabolic activities in patients and enhance the immune response. after december 2019, the ongoing death rate due to a novel flu-like coronavirus disease (covid-19) pandemic has suddenly spread aggressively and continues to increase exponentially. the human to human covid-19 (sars-cov2) is transmitted through the species barrier due to close contact, causing symptoms including extreme fever, cough, pneumonia, acute respiratory disorders, multi-organ failure, and eventually, high mortality among infected patients [1] . the symptoms appear between 5 and 15 days. the "hidden" human carriers also risk the transmission of the virus between close contacts [2] . nonetheless, the exact mechanism of transmission still needs to be checked clinically. covid-19, a highly contagious transmissible disease, has proven to be resistant to the body's own defense mechanism. with corona cases increasing globally, important biological and clinical trends among patients with special conditions are being reported. the high mortality rate of covid-19 is being largely observed in patients with non-communicable diseases (ncds) including cardiovascular disease (cvd), long-term type-2 diabetes (t2d), and renal disease, together along with the elderly population with/without history of ncds [3, 4] . more findings are needed; however, to analyze why vulnerable populations are affected and to define clearly the connection between covid-19 and patients with ncds. the covid-19 virus invades the respiratory tract cells and causes thick mucus formation leading to lung damage and the septic shock which was also observed in patients with vulnerability with acute respiratory distress symptoms (ards) [5] . previous studies clinically consider a compromised immune system for ncd patients (including smokers and non-smokers) [6, 7] . the affected immune system has a significant effect on the cell's metabolic activity and gene expression [8] . just as ncds strike people with reduced resistance or impaired health condition, the "opportunistic" covid-19 has mainly impacted patients with ncds with a compromised immune system [9] . because ncds are the world's leading cause of death, patients receive micronutrient therapy strategies to treat undernutrition, improve immunity, and prevent infection [10, 11] . at the un high-level meeting on the prevention and control of non-communicable diseases, held in new york, usa in september 2011, prevention strategies for ncds have already been addressed with a view to prenatal nourishment, improving diet and nutrients, and preventing undernutrition and infections. since ncds are highly dependent on the individual lifestyle [12] , dietary intake and environmental conditions and exposure often play a role in each person's personal response to a specific disease [13] . the european non-communicable disease prevention and control office (ncd office) of the world health organization (who), in cooperation with the russian federation ministry of health, has developed a plan to tackle the "customized" approach to prevention and control of ncds. treatment of patients can be personalized to help develop a model that characterizes the phenotype and genotype of patients for a more targeted, life-saving treatment due to specific medications and treatment. it is noteworthy that this individualized approach has a potential of obtaining positive results for covid-19 patients, if individuals are thoroughly tested and treated according to their unique metabolic function. for covid-19, which largely is controlling the molecular/ genetic immune system of the host, its complete causal relationship has not been identified with the immune system. however, changes in covid-19 patients along with the physiological factors can be seen in affected body tissue, particularly in the lungs that contribute towards lung injury and ultimately cardiac arrest [14, 15] . circulative factors such as interleukin factors (il-4, il-6, il-10, and il-13) and interferons (ifn-γ), tumor necrosis factor (tnf-α) nuclear factor-κb (nf-κb), cytotoxic t lymphocyte-associated antigen-4 (ctla4), and toll-like receptors-4 (tlr-4) are typically seen in patients with the majority of major ncds [16] [17] [18] . the infection may be targeting gene transcription and regulation of inflammatory markers and chromatin structure machinery of ncd patients [19] . in addition to the body's vital functions, vitamins have an important role to play in immunopathological and physiological response of the body. studies have shown effective treatment for patients with the addition of vitamins and the reduction of inflammatory circulatory markers [20] . the highly regulated machinery depends on these epigenetic modifiers obtained mainly from the diet [21] . as gene regulation and suppression is evident in various vitamin-regulated mechanisms that control epigenetic changes such as dna methylation, histone modification, and post-translation modifications [22, 23] , inflammatory markers are widely known to be controlled by such micronutrients as well [24] [25] [26] [27] . both fat-and water-soluble vitamins have proven to be crucial to epigenetic modification to strengthen the immune system and cell growth of an organism as important micronutrients for patients with ncds [28] . because there is currently no clinically approved covid-19 medication or vaccine available, attempts to improve the immunity of ncd patients with covid-19, vitamin deficiencies should also be tested. the tests would fulfill the requirement to track and regulate proper metabolic activity and immune reactions towards enhanced inflammatory markers. clinical evidence also suggests that vitamin c is beneficial against sars coronavirus [29] and covid-19 is 82% comparable with sars-cov [30, 31] . there is also an urgent need to reduce high mortality rates due to covid-19 and concentrate on an innovative and individual patient strategy to boost therapy effectiveness. the general associations and conclusions identified and reviewed suggest the value of micronutrients to public health experts, and so it is strongly recommended that clinical professionals investigate the alternative treatment further. multiple pathways are activated in ncds. patients with ncds are more prone to infections which can be related with high mortality rates [32] as also observed in covid-19 patients. mechanisms may be linked to vitamin deficiency and its effects that lead to impaired immune response. therefore, early intervention of both clinical and individual preventive and control strategies to help prevent the spread of the infection is important, particularly in people with compromised immunity. the widespread distribution of covid-19 has shown a high mortality rate in ncds and in people with low immunity. a new, holistic approach to providing people with the right vitamin doses can lead to more effective and individual centric therapy. scientific and clinical data show that immune responses in cvd, t2d, ards, cancer, renal diseases, and autoimmune disorders are strongly compromised. genetic control of inflammatory markers should be considered as clinically relevant circulatory markers for covid-19 in individuals with the abovementioned ncds. the fact that vitamins have been recognized as epigenetic modifications in gene expression in methylation, citrullination, acetylation, and phosphorylation [33] can be clinically associated. as can be seen in table 1 , clinical evidence suggests that ncd patients are highly specific with immune sensitive molecules and are deficient in certain types of vitamins [52] . fatal outcomes have been found in covid-19 patients causing acute myocardial injury (mi) and chronic damage. epidemiological data consistently show an increased risk of crp, tlr4, and il-6 with subsequent cardiovascular events [34] [35] [36] . the cvd incidence history shows an altered polymorphism of the − 174/gc that suggests a possibility for cv event in patients along with the snp variant of the crp gene with higher plasma levels [37] . on the other hand, the circulating tlr-4 signal also promotes myocardial infarction. active vitamin d metabolite signaling pathways control various interleukin factor including il-6, crp, and tlr [53] . the epigenetics of this clearly illustrates that vitamin d deficiency is observed in cvd patients [38] with other promoter elements also regulated by vitamins a, e, and b 9/12 . it is worth noting that covid-19 increases the risk of cvd among patients and may be causing over-expression of immune response factors that influence the risk of cv events for covid-19 patients due to vitamin deficiencies. t2d individuals have significant levels of il-4, il-10, il-13, and ifn-γ and tnf-α [54] . individuals having a highly compromised immune system can be explained due to impaired insulin secretion, over-stressed cell organelles such as endoplasmic reticulum and oxidative stress, and glucotoxicity [55] . the cellular stress in t2d induces inflammatory response due to specific cytokines and chemokines [56] . in addition to t2d patients being prone to infections, the patients suffer from vitamins b 9 (folic acid), b 12 , a, c, and e deficiencies [43] , hence absence in maintenance of chromatin structure of cell genome, increased apoptosis, and absence of protein integrity. overall, there is complete absence of epigenetic control of cellular processes in t2d individuals making them susceptible to infectious diseases. scientific evidence shows ards patients to express nf-κb and grα leading to dysregulated mechanisms which leads to up-or down-regulation of various pro-inflammatory mediators and increased oxidative stress [57] . transcriptional mediators such as nf-κb expressed in ards are attenuated by vitamin c; however, vitamin d and e deficiency in ards patients also indicate absence of epigenetic control on gene transcription due to possible absence of proper dna methylation and histone modification status in the cells [44] which may contribute towards dysregulated transcriptional mechanism. patients with covid-19 tend to develop severe immune activation in lungs [14] and hence pneumonia. the clinical link between active inflammatory pathways in ards and the vitamin deficiency clearly indicates why covid-19 causes high mortality in patients with chronic lung diseases. epidemiological data confirm higher prevalence of cancer patients with covid-19. cancer patients with history of immunosuppressants who are covid-19 positive are also facing worse outcomes [58] . ctl4a and pd1 are two of the main immune adaptive response regulators that inhibit the normal tregulatory cell in cancer-stricken patients. inhibition of both tumor markers resulted in clinical trials to provide anti-ctl4a and anti-pd1 antibodies for cancer therapy, which may be useful for regulating a t cell proliferation signaling pathway [59, 60] . the possible balance between controlling ctl4a and pd1 expression [48] , as well as providing vitamin fatalities in kidney patients are also investigated, provided that covid-19 patients with ongoing kidney and renal disease are controlled with a high degree of caution [62, 63] . signs of kidney dysfunction include elevated proteinuria, urea and serum potassium, hematuria, and other clinical comorbidity [64] . patients with a history of failure of kidney disease develop inflammation which contributes to the activation of the adaptive immunity of increased th1/th2 ratios and to t and b lymphocyte autoantibodies [51] . infectious pathogens may easily enter the kidney patients. this possibility should also be timely addressed in covid-19 patients to prevent end-stage renal diseases (esrd). in kidney patients, vitamin d is discovered to be deficient, putting them at risk of ckd and hyperparathyroidism. the vitamin suppresses most of the adaptive immune system which can play an important role in protecting the host against first-line defense invasion of covid-19. in the covid-19 patients with kidney transplant [65] , vitamin d may prove effective and this may also prevent graft rejection and regulate th1/th2 ratios. micronutrient therapy to be considered and given should be individual centric and based upon time and dose-response manner. vitamin therapy seems feasible at this time due to absence of the vaccine or medication available for care to prevent multiple organ failure and immunologic deaths among covid-19-positive patients with ncd. table 2 summarizes the vitamins that control the immunomodulatory elements and the mechanism of action. if the population receives the right dose of vitamins specific to ncd and inflammatory based on primary observation on previous evidences, the types of vitamin combinations which can be given to patients are shown in table 3 . based on clinical evidence, the table combines the types of vitamins which can be selected to enhance the immunity of patients to reduce the inflammatory response in ncd patients. there is strong need for personalized treatment for covid-19 patients suffering from ncd as an alternative therapy [88] . the compilation of literature, shown in table 3 , citing clinical evidence for a potential vitamin link in the control of immune expression of inflammatory markers to treat an infectious pandemic [89] , needs to be clinically validated. as vitamins regulate the epigenetic machinery, age, sex, smoking, ethnicity, and other environmental/lifestyle factors are also affected by changes to immune response. several ncds are driven by genomic instability, hypermethylation, and hypomethylation of promoter gene regions involved in immunological marker and element regulation. treating vitamins as major epigenetic modifiers will prove to be an effective approach to customized treatment, particularly for covid-19 patients with different background factors that could have contributed in the past to develop the specific ncd. vitamin therapy can be an effective and safe treatment as a custom drug. in covid-19 patients, the storm of inflammatory or cytokine factors should be tested by assessing patients for different inflammatory markers and vitamin deficiency. in order to provide a metabolism for an individual against vitamin deficiency, all individuals should be screened for specific immune cell reactions and the factors represented by the specific ncd. the combination will improve care and lead to a more personalized approach. an exhaustive review is also needed for other factors such as pregnancy and other medical conditions. this can be used as time progresses and new clinical data for covid-19 patients are available. this study can serve as a primary link to open ways to look at important facts to cure people, otherwise having compromised ncd, non-communicable disease; cvd, cardiovascular disease; t2d, type-2-diabetes; ards, acute respiratory distress syndrome immune systems due to ncds. this may include more studies and recommendation of personalized approach for patients to be treated. the benefit is that vitamin therapy has no side effect and has proven to be effective. the micronutrient combination is also recommended for the target population without ncd or help early in its prevention of infectious diseases for patients at risk for covid-19. other factors, such as smoking and drinking, should not be overlooked. this will also extend guidelines and policy changes to undernutrition and infections in low-and middle-income countries. therefore, opportunistic infections can be better controlled in the future with low mortality rate, and vitamins can serve as useful epigenetic modifiers to genetically target and modify transcriptional and translational control of various inflammatory markers. conflict of interest the authors declare they have no conflict of interest. human and animal rights and informed consent this article does not contain any studies with human or animal subjects performed by any of the authors. papers of particular interest, published recently, have been highlighted as: • of 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cardiovascular disease 25-dihydroxyvitamin d3 inhibits anti-cd40 plus il-4-mediated ige production in vitro vitamin e inhibits endotoxin-mediated transport of phosphatases to lipid rafts vitamin d3 administration to ms patients leads to increased serum levels of latency activated peptide (lap) of tgf-beta the article is of importance as it highlights supplementation of vitamin d reduced respiratory infections in patients. the article is a guided support for further clinical trial to reduce vitamin c blocks tnf-αinduced nf-kb activation and icam-1 expression in human neuroblastoma cells the article is of outstanding importance as it outlines potential role of vitamin a as an epigenetic modulator. it highlights that nutritional supplementations have medical benefits in health and diseases effect of vitamin d supplementation on cathelicidin, ifn-γ, il-4 and th1/ th2 transcription factors in young healthy females vitamin d and susceptibility of chronic lung diseases: role of epigenetics mounting evidence for vitamin d as an environmental factor affecting autoimmune disease prevalence inhibition of nf-κb activation by vitamin e derivatives vitamin d interferes with glucocorticoid responsiveness in human peripheral blood mononuclear target cells 1, 25-dihydroxyvitamin d3 and il-2 combine to inhibit t cell production of inflammatory cytokines and promote development of regulatory t cells expressing ctla-4 and foxp3 altered expression of ctla-4, cd28, vdr, and cd45 mrna in t cells of patients with hashimoto's thyroiditis-a pilot study immunomodulation by vitamin b12: augmentation of cd8+ t lymphocytes and natural killer (nk) cell activity in vitamin b12-deficient patients by methyl-b12 treatment negative regulation of cd95 ligand gene expression by vitamin d3 in t lymphocytes increased vitamin e intake restores fish-oilinduced suppressed blastogenesis of mitogen-stimulated t lymphocytes human t lymphocytes are direct targets of 1, 25-dihydroxyvitamin d3 in the immune system requirements for induction of vitamin d-mediated gene regulation in normal human b lymphocytes all-trans-retinoic acid accelerates the differentiation of human b lymphocytes maturing into plasma cells vitamin a supplementation and serum th1-and th2-associated cytokine response in women the article is of outstanding importance. the suggestions provided in this article call for immediate action against considering precision epidemiology to overcome covid-19 pandemic. it calls for intensive testing against reinfection, immunological response in individuals contribution of selected vitamins and trace elements to immune function nutritional supplements for older adults: review and recommendations-part i publisher's note springer nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations key: cord-296836-aizquh16 authors: brenner, hermann; holleczek, bernd; schöttker, ben title: vitamin d insufficiency and deficiency and mortality from respiratory diseases in a cohort of older adults: potential for limiting the death toll during and beyond the covid-19 pandemic? date: 2020-08-18 journal: nutrients doi: 10.3390/nu12082488 sha: doc_id: 296836 cord_uid: aizquh16 the covid-19 pandemic goes along with increased mortality from acute respiratory disease. it has been suggested that vitamin d(3) supplementation might help to reduce respiratory disease mortality. we assessed the prevalence of vitamin d insufficiency and deficiency, defined by 25-hydroxyvitamin d (25(oh)d) blood levels of 30–50 and <30 nmol/l, respectively, and their association with mortality from respiratory diseases during 15 years of follow-up in a cohort of 9548 adults aged 50–75 years from saarland, germany. vitamin d insufficiency and deficiency were common (44% and 15%, respectively). compared to those with sufficient vitamin d status, participants with vitamin d insufficiency and deficiency had strongly increased respiratory mortality, with adjusted hazard ratios (95% confidence intervals) of 2.1 (1.3–3.2) and 3.0 (1.8–5.2) overall, 4.3 (1.3–14.4) and 8.5 (2.4–30.1) among women, and 1.9 (1.1–3.2) and 2.3 (1.1–4.4) among men. overall, 41% (95% confidence interval: 20–58%) of respiratory disease mortality was statistically attributable to vitamin d insufficiency or deficiency. vitamin d insufficiency and deficiency are common and account for a large proportion of respiratory disease mortality in older adults, supporting the hypothesis that vitamin d(3) supplementation could be helpful to limit the burden of the covid-19 pandemic, particularly among women. the corona virus disease 2019 (covid-19) pandemic goes along with strongly increased respiratory disease mortality. it has been suggested that vitamin d 3 supplementation could be a potentially promising and safe approach to reduce risk of covid-19 infections and deaths [1] . meta-analyses of randomized clinical trials (rcts) have shown that vitamin d 3 supplementation reduces the risk of acute respiratory tract infections [2] . risk reduction with regular (daily or weekly) supplementation of physiological doses of vitamin d was especially strong (by 70%) among people with vitamin d deficiency, but significant risk reduction (by 25%) was also found among people with higher vitamin d levels. meta-analyses of clinical trials have demonstrated that vitamin d 3 supplementation has the potential to also reduce cancer mortality by approximately 13% [3] . people with pre-existing major diseases, such as diabetes or cancer, are at increased risk of dying from severe acute respiratory syndrome coronavirus 2 (sars-cov-2) infections. at the same time, prevention of and care for these diseases have been and keep being strongly compromised by current measures to limit the covid-19 pandemic. we previously assessed the prevalence of vitamin d insufficiency and deficiency and their association with all-cause mortality and mortality from cardiovascular, cancer and respiratory diseases during a mean follow-up of 9.5 years in a cohort of 9548 adults aged 50-75 years from saarland, germany [4] [5] [6] [7] [8] . in our previous analysis, the number of deaths from respiratory disease had still been rather small (n = 55). we aim to present considerably updated and sex-specific follow-up data of 15 years here and to calculate the proportion of respiratory disease mortality that is attributable to vitamin d insufficiency and deficiency. furthermore, we discuss potential implications for prevention in the context of the ongoing covid-19 pandemic. this investigation is based on the esther study (german name: epidemiologische studie der verhütung, früherkennung und optimierten therapie chronischer erkrankungen in der älteren bevölkerung), an ongoing statewide cohort study from saarland, germany, details of which have been reported elsewhere [4] [5] [6] [7] [8] [9] . briefly, 9940 men and women, aged 50-75 years at baseline, were recruited by their general practitioners during a routine health check-up between 2000 and 2002. blood samples were taken at baseline at the general practitioners' offices. information on socio-demographic and lifestyle characteristics and medical history were obtained by questionnaires from participants and their general practitioners, and the distribution of those characteristics was similar to the distribution in the respective age categories in the german national health survey conducted in a representative sample of the german population in 1998 [9] . the esther study was approved by the ethics committees of the university of heidelberg and the state medical board of saarland, germany. written informed consent was issued by all participants. information on socio-demographic characteristics, lifestyle and diet were obtained by a comprehensive self-administered questionnaire from the study participants at baseline. skin colour, race or ethnicity were not individually recorded. however, we assume that close to 100% of this german cohort of adults aged 50 years and older has white skin colour since 99% gave the information that they were born in germany (94%) or another european country (5%). height and weight were assessed and documented on a standardized form by the general practitioners during the health check-up. furthermore, blood and urine samples were taken during the health check-up, centrifuged, sent to the study center and stored at −80 • c until analysis. the most abundant and stable vitamin d metabolite in blood samples, 25-hydroxyvitamin d (25(oh)d) levels, was measured from stored serum samples taken at recruitment. the laboratory methods used are described in detail elsewhere [4] . in brief, 25(oh)d levels in women were measured with the diasorin-liaison analyzer (diasorin inc., stillwater, ok, usa). analyses in men were conducted in the context of a separate research project several years later (when the diasorin measurements were no longer offered) with ids-isys (immunodiagnostic systems gmbh, frankfurt main, germany). both immunoassays were standardized retrospectively to the gold standard method liquid chromatography tandem-mass-spectrometry. deaths until end of 2016 were identified by inquiry at the residents' registration offices and death certificates of deceased study participants were provided by local health authorities. the leading cause of death with an icd-10 code was available for 98.9% of deceased study participants and was coded with icd-10 codes r98-r99 "unknown cause of death" for 4.4% of deceased participants. these individuals were not excluded and censored at the time of death for cause-specific mortality outcomes. participants of the esther baseline examination (n = 9940) were excluded from this investigation if no blood sample was available or 25(oh)d could not be measured (n = 368) or if they could not be followed-up for mortality (n = 24), which resulted in a total sample size of n = 9548 subjects for this analysis. we used the institute of medicine's cut-offs to define adequate vitamin d status (>50 nmol/l), vitamin d insufficiency (30-50 nmol/l) and vitamin d deficiency (<30 nmol/l) [10] . we assessed prevalence of vitamin d insufficiency and deficiency and the distribution (median, interquartile range) of 25(oh)d values in the total study population and according to age, sex, lifestyle factors and major diseases. we provide kaplan-meier curves for mortality from respiratory diseases among participants with sufficient vitamin d status, vitamin d insufficiency and deficiency and conducted log-rank tests with comparison to the reference group "sufficient vitamin d status." in addition, dose-response relationships between 25(oh)d levels and respiratory disease mortality were estimated by restricted cubic splines [11] . furthermore, we compared all-cause, cardiovascular disease, cancer, and respiratory disease mortality between subjects with vitamin d insufficiency or deficiency and subjects with adequate 25(oh)d levels and estimated hazard ratios (hr) with 95% confidence intervals (95% ci) by multivariable cox proportional hazards models. missing values for covariates ranged from 0% to 5.8% (for fish consumption). missing covariate values were imputed with multiple imputation using the markov chain monte carlo (mcmc) method with 200 burn-in iterations. twenty data sets were generated. the imputation model consisted of all variables of the full model (modelled as used in the full model) but not the outcome data, and the imputation was carried out stratified by sex. we used an age, sex and season adjusted model and a full model that was adjusted for potential confounders, which are listed in table 1 . additional adjustment for potential intermediates (cardiovascular disease, history of cancer, diabetes mellitus, hypertension, asthma, total serum cholesterol and serum c-reactive protein levels) did not lead to substantially different results (data not shown). age and body mass index (bmi) were modelled as continuous variables and all other variables were modelled with the categories shown in table 1 . furthermore, sex-specific analyses were performed and statistical tests on interaction were carried out. finally, we estimated the population attributable fraction (paf) of respiratory disease mortality from the prevalence of vitamin d insufficiency and deficiency and their associations with respiratory disease mortality, as derived from the full model. the paf of mortality is the share of mortality in a population that is statistically attributable to a risk factor and that could be avoided by entirely eliminating that risk factor (here: vitamin d insufficiency or deficiency) [12] . all statistical tests were two-sided, and the alpha level of significance was set to 0.05, with no adjustment for multiple testing. all statistical analyses were conducted with the software package sas, version 9.4 (cary, nc, usa). the study population included 43.8% men, mean age was 62. the study population included 43.8% men, mean age was 62.1 years. among the 9548 participants included in the study, 4186 (43.8%) had vitamin d insufficiency (25(oh)d levels of 30-<50 nmol/l) and 1438 (15.1%) had vitamin d deficiency (25(oh)d levels <30 nmol/l) ( figure 1 ). furthermore, 13 (0.1%) had too high 25(oh)d levels >200 nmol/l. table 1 provides a description of the characteristics of the study population at baseline as well as prevalence of vitamin d insufficiency and deficiency and median 25(oh)d levels according to those characteristics. both vitamin d insufficiency and deficiency were more frequent among females with higher age and bmi. in subjects with low physical activity and those who consumed fish less than once per week, median 25(oh)d levels were correspondingly lower. a seasonal variation with lower 25(oh)d levels in winter than in summer months was also observed. moreover, 25(oh)d levels were particularly low among subjects with low education and current smokers. table 1 provides a description of the characteristics of the study population at baseline as well as prevalence of vitamin d insufficiency and deficiency and median 25(oh)d levels according to those characteristics. both vitamin d insufficiency and deficiency were more frequent among females with higher age and bmi. in subjects with low physical activity and those who consumed fish less than once per week, median 25(oh)d levels were correspondingly lower. a seasonal variation with lower 25(oh)d levels in winter than in summer months was also observed. moreover, 25(oh)d levels were particularly low among subjects with low education and current smokers. overall, 2363 (24.7%) study participants died during a median of 15.3 years of follow-up, of whom 815, 825 and 123 died from cardiovascular disease (cvd), cancer and respiratory disease, respectively. figure 2 shows the kaplan-meier curves for deaths from respiratory disease according to vitamin d status. mortality from respiratory diseases was consistently highest among participants with vitamin d deficiency and consistently lowest among those with sufficient vitamin d levels throughout up to 16.5 years of follow-up. the log-rank test indicated statistically significant survival differences with respect to respiratory disease mortality between the groups with vitamin d deficiency and sufficient vitamin d (p < 0.0001), as well as for the comparison of subjects with vitamin d insufficiency and sufficient vitamin d (p = 0.023). it is not statistically significant that 25(oh)d levels >75 nmol/l are associated with further decreasing respiratory disease mortality because the confidence interval is large and includes the null effect value of hr = 1. curves were assessed by using restricted cubic splines with knots at 25-hydroxyvitamin d concentrations of 30, 60, 90 and 120 nmol/l, and a 25-hydroxyvitamin d concentration of 75 nmol/l was used as the reference. the cox proportional hazards regression model was adjusted for sex, age, season of blood draw, school education, smoking, bmi, physical activity, and fish consumption. table 2 shows the associations of vitamin d status with all-cause, cvd, cancer and respiratory disease mortality after adjustment for multiple potential confounders. vitamin d insufficiency and nutrients 2020, 12, 2488 6 of 11 deficiency were associated with significantly increased all-cause mortality compared to sufficient vitamin d status (full model hrs (95%ci): 1.2 (1.1-1.3) and 1.7 (1.5-1.9), respectively) ( table 2) . vitamin d deficiency was also associated with significant increases in cvd and cancer mortality by 52% and 38%, respectively (full model results). however, vitamin d insufficiency and deficiency were particularly strongly associated with respiratory disease mortality with full model hrs of 2.1 (95%ci: 1.3-3.2) and 3.0 (95%ci: 1.8-5.2), respectively. overall, 41% (95%ci: 20-58%]) of all deaths from respiratory diseases were statistically attributable to 25(oh)d levels <50 nmol/l. figure 3 presents results on the adjusted dose-response relationship between 25(oh)d levels and respiratory disease mortality. mortality strongly increased with decreasing 25(oh)d levels below 50 nmol/l and even more so below 30 nmol/l, i.e., in the vitamin d insufficiency and deficiency range. it is not statistically significant that 25(oh)d levels >75 nmol/l are associated with further decreasing respiratory disease mortality because the confidence interval is large and includes the null effect value of hr = 1. table 3 shows the results of the sex-specific analyses. for all-cause, cardiovascular disease and cancer mortality, only modest, statistically non-significant differences were seen between women and men. although significant increases were seen for respiratory disease mortality in both women and men, they were much stronger among women, with 8.5 (95% ci 2.4-30.1) and 2.3 (95% ci 1.1-4.4)-fold increase of respiratory disease mortality in the case of vitamin d deficiency among women and men, respectively. however, the number of respiratory deaths among women was small (n = 42 overall), especially in the reference groups of those with 25(oh)d > 50 nmol/l (n = 3), which resulted in very wide confidence intervals of the estimated hazard ratios. in this large population-based cohort study from saarland, germany, the majority of participants aged 50-75 years at baseline had vitamin d insufficiency or deficiency, and these conditions were associated with increased mortality. in particular, mortality from respiratory diseases was increased by 2.1-and 3.0-fold in subjects with vitamin d insufficiency or deficiency, respectively, compared to participants with sufficient vitamin d status. significant associations with respiratory disease mortality were seen among both women and men, but they were particularly strong for women. overall, 41% of deaths from respiratory diseases were statistically attributable to vitamin d insufficiency or deficiency and could possibly be avoided by overcoming these conditions, assuming causality of the association. the assumption of causality of vitamin d 3 effects on mortality obviously requires most careful discussion. although we made the best attempts to adjust potential confounding factors, we cannot exclude the possibility of residual confounding by imperfect measurement of confounding variables, such as smoking or physical activity, or omission of unknown confounders. as addressed in detail elsewhere [6] , interpretation of the evidence is further complicated by the fact that vitamin d deficiency could be considered both a consequence of poor health as well as a risk factor for increased vulnerability to acute disease and poor outcomes of chronic diseases among people with poor health. our findings therefore require critical discussion in the light of additional criteria and evidence, such as biological mechanisms and plausibility, and, in particular, in the light of data from rcts providing vitamin d 3 supplementation. deaths from respiratory disease are mostly deaths from lower respiratory infections [13] . vitamin d 3 is thought to protect from occurrence and poor outcomes of respiratory infections by several mechanisms, including enhanced physical barriers (maintenance of junction integrity), cellular innate immunity, and adaptive immunity [1] . innate and adaptive immunity are being influenced by sex hormones [14] , which may explain the observed interaction of sex and 25(oh)d levels with respiratory disease mortality. according to data from the us-american national health and nutrition survey, women have a higher inflammation burden than men (the age range was 40-90+ years [15] ). especially postmenopausal women, like those included in the esther study, have a high inflammatory burden because a decline in estrogen levels during menopause is associated with an increased expression of pro-inflammatory cytokines, including interleukin 6 and tumor necrosis factor (tnf) α [14, 16, 17] . a cytokine storm as an adverse immune response to a sars-cov-2 infection is currently a major hypothesis for the underlying cause of a large proportion of covid-19 deaths [18] . sufficient 25(oh)d levels are suggested to contribute to prevention of the cytokine storm [1, 19, 20] . vitamin d is known to interact with the angiotensin-converting enzyme 2 (ace2), which is both used by sars-cov-2 as an entry receptor and is an important protein on an anti-inflammatory pathway [21] . while sars-cov-2 downregulates the expression of ace2, vitamin d upregulates it. in a meta-analysis of individual participant data of 25 rcts that included 11,321 participants aged 0-95 years, vitamin d 3 supplementation was shown to reduce the risk of acute respiratory tract infection (or 0.88, 95% ci 0.81-0.96) [2] . the best effects were shown for daily or weekly vitamin d 3 supplementation without additional bolus doses (or 0.81, 95% ci 0.72 to 0.91). the protective effects were particularly strong in those with baseline 25-hydroxyvitamin d levels <25 nmol/l (or 0.30, 95% ci 0.17-0.53). in a recent meta-analysis of rcts on vitamin d 3 supplementation for patients with chronic obstructive pulmonary disease (copd), the risk of acute exacerbations was estimated to be reduced by 61% (95% ci 36-77%) [22] . in remarkable consistency with our results, these meta-analyses of rcts provide strong evidence for the preventive potential of vitamin d 3 supplementation against acute respiratory infections and copd exacerbations in particular. it appears plausible to assume that the anti-inflammatory mechanisms of vitamin d would be relevant for sars-cov-2 infections in a similar manner as for other severe viral respiratory diseases, such as influenza. a first study posted on a pre-print server on 13 may 2020 suggests that the protective effects of vitamin d 3 on other acute respiratory tract infections may be translated to covid-19 infections [23] . vitamin d deficiency and vitamin d 3 treatment data were available for 499 covid-19 patients from chicago for the year prior covid-19 testing. being likely vitamin d deficient (defined as being vitamin d deficient at last available time point without increase of vitamin d treatment) at the time of covid-19 testing was associated with a 1.8-fold increased risk of being tested positive for covid-19 (p < 0.02) as compared to likely vitamin d sufficient. it is worth noting that beneficial effects of vitamin d 3 supplementation against manifestation or exacerbation of acute respiratory infection during an epidemic would be expected to go beyond individual protection of those using supplementation, as limiting such manifestation and exacerbation would also be expected to reduce the potential of spread of the disease to other persons and relieve the overload of the medical system by the epidemic. to our knowledge, no previous vitamin d 3 supplementation rcts have addressed mortality from respiratory disease as the primary endpoint, and no meta-analysis of results for this specific endpoint have been reported, which most likely reflects the relatively small share of deaths from respiratory diseases among all deaths. in our cohort of older adults, these deaths accounted for 5.2% of all deaths. even though this proportion is expected to be higher during the covid-19 pandemic, the majority of deaths still occur from other diseases, and the summary effect, benefit-harm ratio and cost-effectiveness with respect to all relevant outcomes therefore deserve most careful attention for any general prevention efforts. in that respect, vitamin d 3 supplementation appears to be a particularly promising approach, especially for population groups with high prevalence of vitamin d insufficiency or deficiency, such as the elderly and those with severe comorbidities (which essentially coincide with population groups at highest risk of severe course and death from sars-cov-2 infection [24] ). the personal, health care and societal costs of the vitamin d 3 intervention are negligibly low compared to the very high costs of currently employed "general population measures," such as extensive testing for the infection and the lockdown of large proportions of economic and social life, including the delay or omission of much of routine medical care for other relevant diseases. in fact, some of these measures are expected to severely aggravate vitamin d insufficiency or deficiency, especially in high risk groups, such as restrictions of spending time outdoors for the total population (as practiced, for example, in france and spain) or certain high risk groups, such as nursing home residents (as practiced in many countries, including germany). such restrictions dramatically reduce opportunities to maintain adequate vitamin d levels through endogenous synthesis by relevant sun exposure. avoidance of sun exposure has been shown to be associated with increased mortality in epidemiological studies [25] . vitamin d 3 supplementation has been demonstrated to be safe in numerous large-scale studies, and the risk of harm seems to be negligible compared to the risk of harmful side effects of the aforementioned and other general population measures, such as delayed diagnosis and treatment of cancer, myocardial infarction or stroke, withheld or deferred delivery of surgical or other medical services, or health risks related to unemployment and loneliness [26] [27] [28] [29] . on the contrary, one expected "side effect" would be reducing total cancer mortality by 13%, as suggested by a recent meta-analysis of rcts [3] . for germany, with currently approximately 230,000 deaths from cancer per year [30] , this would translate in prevention of approximately 30,000 cancer deaths each year, suggesting substantial additional benefit besides lowering the covid-19 burden during the covid-19 pandemic and beyond. in conclusion, our results, along with evidence from meta-analyses from rcts regarding results of vitamin d 3 supplementation on various outcomes, suggest that vitamin d 3 supplementation could contribute to lowering mortality from respiratory and other diseases during and beyond the covid-19 pandemic, in particular among women. the endocrine society recommends 1500-2000 iu vitamin d 3 /day for adults of any age at high risk for vitamin d deficiency [31] . the costs for such supplementation are in the order of 30 € per person per year, or even half that amount when sufficient vitamin d supply is ensured by carefully dosed sun exposure during the summer months. along with expected savings from prevented respiratory and other diseases, this would make vitamin d 3 supplementation a particularly cost-effective and most likely cost-saving measure, whose currently still widely neglected potential should receive increased attention in the debate on how to fight against the covid-19 pandemic. author contributions: h.b. designed the research and drafted the manuscript, b.s. conducted statistical analyses, and b.h. critically read and commented the manuscript and added aspects to the discussion. all authors contributed to the data collection for this project. all authors have read and agreed to the published version of the manuscript. evidence that vitamin d supplementation could reduce risk of influenza and covid-19 infections and deaths vitamin d supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data vitamin d supplements and total cancer incidence and mortality: a meta-analysis of randomized controlled trials strong associations of 25-hydroxyvitamin d levels with all-cause, cardiovascular, cancer and respiratory disease mortality in a large cohort study consortium on health and ageing: network of cohorts in europe and the united states. vitamin d and mortality: meta-analysis of individual participant data from a large consortium of cohort studies from europe and the united states vitamin d as a resilience factor, helpful for survival of potentially fatal conditions: a hypothesis emerging from recent findings of the esther cohort study and the chances consortium vitamin d supplementation trials aimed at reducing mortality have much higher power when focusing on people with low serum 25-hydroxyvitamin d concentrations serum 25-hydroxyvitamin d levels as an aging marker: strong associations with age and all-cause mortality independent from telomere length, epigenetic age acceleration, and 8-isoprostane levels epidemiological investigations of the chances of preventing, recognizing early and optimally treating chronic diseases in an elderly population (esther study) dietary reference intakes for calcium and vitamin d dose-response analyses using restricted cubic spline functions in public health research world health organization health statistics and information systems global, regional, and national age-sex-specific mortality for 282 causes of death in 195 countries and territories, 1980-2017: a systematic analysis for the global burden of disease study the confluence of sex hormones and aging on immunity sex differences in age trajectories of physiological dysregulation: inflammation, metabolic syndrome, and allostatic load the complex role of estrogens in inflammation transitions in metabolic and immune systems from pre-menopause to post-menopause: implications for age-associated neurodegenerative diseases the possible pathophysiology mechanism of cytokine storm in elderly adults with covid-19 infection: the contribution of "inflame-aging" the possible role of vitamin d in suppressing cytokine storm and associated mortality in covid-19 patients vitamin d receptor stimulation to reduce acute respiratory distress syndrome (ards) in patients with coronavirus sars-cov-2 infections vitamin-d and covid-19: do deficient risk a poorer outcome? the efficacy of vitamin d therapy for patients with copd: a meta-analysis of randomized controlled trials association of vitamin d deficiency and treatment with covid-19 incidence risk factors of critical & mortal covid-19 cases: a systematic literature review and meta-analysis avoidance of sun exposure is a risk factor for all-cause mortality: results from the melanoma in southern sweden cohort decline of acute coronary syndrome admissions in austria since the outbreak of covid-19: the pandemic response causes cardiac collateral damage covid-19 pandemic will have a long-lasting impact on the quality of cirrhosis care potential impact of the covid-19 pandemic on financial toxicity in cancer survivors immediate and long-term impact of the covid-19 pandemic on delivery of surgical services krebs in deutschland für evaluation, treatment, and prevention of vitamin d deficiency: an endocrine society clinical practice guideline the esther study was funded by grants from the saarland state ministry for social affairs, health, women and family affairs (saarbrücken, germany), the baden-württemberg state ministry of science, research and arts (stuttgart, germany), the federal ministry of education and research (berlin, germany) and the federal ministry of family affairs, senior citizens, women and youth (berlin, germany). the authors declare no conflict of interest. key: cord-331191-mq1zwpt7 authors: mandrioli, mara; boselli, emanuele; fiori, federica; rodriguez-estrada, maria teresa title: vitamin d3 in high-quality cow milk: an italian case study date: 2020-05-01 journal: foods doi: 10.3390/foods9050548 sha: doc_id: 331191 cord_uid: mq1zwpt7 the quality-labeling category of high-quality (hq) milk defined by the italian legislation must comply with specific requirements concerning rigorous breeder management, hygienic controls, fat and protein content, bacterial load, somatic cells, lactic acid content, and non-denatured soluble serum proteins. however, there is no specification for the vitamin d content of hq milk. moreover, the data on the vitamin d content of this milk category are very scarce. in the present study, the content of vitamin d3 was evaluated in hq raw and pasteurized cow milk obtained from italian cowsheds and supermarkets. the vitamin d3 content varied from not detected (less than 1 µg l(−1)) to 17.0 ± 2.0 µg l(−1) milk and was not related to the milk fat content. these results represent a case study including a significant although not exhaustive part of the contemporary italian market of hq milk. it was shown for the first time that hq raw milk does not necessarily contain more vitamin d3, even though non-expert consumers likely to buy milk labeled as hq could expect it. the vitamin d3 content in hq pasteurized whole milk should be reported on the label of the milk package as a best practice of consumer information policy. vitamin d is a fat-soluble vitamin that plays an essential role in bone metabolism, by properly adjusting the concentration of calcium and phosphorus in the human body. many studies have shown the correlation between the dietary intake of vitamin d and improvement in certain diseases, such as glycemic index in patients with diabetes mellitus type i [1] . hypovitaminosis d has also been associated with loss of muscle mass and bone frailty, especially in elderly people [2] . very recent studies suggest that proper supplementation of vitamin d3 may enhance our resistance to sars-cov-2 [3] , influenza and pneumonia infections [3, 4] , as well as may reduce the incidence and severity of covid-19 by increasing the serum 25-hydroxyvitamin d concentration [5] . vitamin d is synthesized in humans, mainly by skin exposure to uv-b sunlight. the two major forms are d2 (ergocalciferol) and d3 (cholecalciferol) from plant and animal food, respectively. the major food sources of vitamin d are fishery products, eggs, cereals and dairy products. vitamin d3 is present in milk and diverse concentrations have been reported: 0.13-1.0 µg/l [6] , 0.13-0.88 µg/l [7] , 0.08-1.35 µg/kg and 0.03-1.86 µg/kg in whole milk and whole organic milk, respectively [8] . nevertheless, milk has always been considered a poor source of vitamin d. the content of fat-soluble vitamins a, d, and e in milk is strongly influenced by the food ration composition of the dairy cow [9] . the vitamin d content is greatly affected by the lipid content and season. moreover, some differences have been observed between organic and conventional milk [8] . currently, the interest and attention of livestock production are aimed at improving not only human nutrition [10] but also the cattle's health conditions. the technique of constant or 'unifeed' ration (from unique fed, or "unique food") is a cattle feeding method, which has replaced the traditional method (or "single dish") of feed administration. the efficacy of the composition and quality of the food ration 'unifeed' has been widely demonstrated; thus, this type of food ration is widely used in the livestock production to improve the nutritional profile of milk. in italy, the quality-labeling category of high-quality (hq) milk is regulated by the decree of the italian ministry of health no. 185/1991 [11] , which imposes rigorous breeder management and hygienic controls regarding fat and protein content, bacterial load, somatic cells, lactic acid content, and non-denatured soluble serum proteins [12] . although there is no indication about the vitamin d content of hq milk, consumers would presumably expect a higher content of vitamin d in this milk category, since the starting hq raw milk must comply with more precise and stricter hygienic and composition requirements. hq milk has a higher minimum fat content and must be subjected to a gentler pasteurization treatment, such as high temperature-short time pasteurization (htst, 72 • c for 15 s) which is supposed to better preserve the micronutrient content (fat-soluble vitamins included) with respect to conventional pasteurization. the assessment of vitamin d in milk is a laborious analytical determination, due to the matrix complexity and the need for high sensitivity. the presence of other minor lipophilic components (such as carotenoids, retinol, tocopherols, and sterols) can interfere with vitamin d determination, causing an overestimation. in addition, the sample purification step can lead to large analyte losses if the extraction yield is not optimal. for these reasons, it is necessary to apply analytical methods with high specificity. the most widely used analytical procedure involves saponification, purification, and quantification with high-performance liquid chromatography (hplc) coupled to the ultraviolet-diode array detector (uv-dad) or mass spectrometry (ms) detector [13] to confirm the identification. since the concentration of cholecalciferol in milk is important to assess the daily intake in humans, the present study aimed at evaluating the content of vitamin d3 in raw milk and pasteurized hq whole milk obtained according to the italian ministerial decree 185/1991 [11] . the obtained data set presented here for the first time on hq milk represents a case study including a significant although not exhaustive part of the contemporary italian market for this specific quality-labeling category of milk. all chemicals and solvents were of analytical grade. hplc-grade methanol (≥99.9%), ammonia 14 mol/l, ethanol (96%), ethyl ether (≥99.5%), n-pentane, aqueous solution of na 2 so 4 at 10% (w/v), anhydrous sodium sulfate powder (≥99.9%), and water (≥ 99.8%), were purchased from merck (darmstadt, germany). the standards of vitamins d2 and d3 were supplied by sigma (st. louis, mo, usa). silica solid-phase extraction (spe) cartridges (strata si-1, 55 µm, 70 å, 500 mg/3 ml) from phenomenex (torrence, ca, usa), were used for vitamin d3 purification. twenty-two samples of hq raw milk (farm) were collected directly from farms producing hq milk (according to the guidelines of the italian ministerial decree 185/1991), which delivered it directly to an italian dairy company. the farms were mainly located in emilia romagna, lombardia and veneto regions, and were of medium and large size. the friesian dairy cows were fed with unifeed or "single pot", which could guarantee the administration of a homogeneous and nutritionally balanced food ration. to maintain health and animal welfare, the daily food ration was added with a "mineral feed" for the integration of vitamins and oligo elements. given that the supplement intake with the daily ration was about 500 g per day per head, and that it represented the only source of vitamin d3 intake, a daily intake per head of 950 µg of vitamin d3 could be assumed. milk sampling was carried out by collecting raw mass milk of at least 2 or 4 milkings. before sampling, the homogenizer was operated for few min, in order to avoid fat creaming at the milk surface and thus obtain a representative sample of the entire milk mass. milk was collected in sterile 1.5 l pet bottles, kept at a temperature between 2 and 6 • c during transportation, and frozen at −18 • c until analysis. eight samples of pasteurized hq whole milk (phq) from the same dairy company were purchased in an italian supermarket in the same period. to obtain phq, milk underwent homogenization and htst pasteurization at 72-75 • c for 15 s. all farm and phq samples were subjected to fat cold extraction according to the procedure described in section 2.4, as well as to the determination and quantification of the vitamin d3 content by high performance liquid chromatography coupled to a photodiode array (hplc/uv-dad) detector and hplc coupled to mass spectrometry (hplc/ms). two independent replicates were performed for each sample. vitamin d3 was determined with an analytical procedure consisting of direct cold saponification, extraction of the unsaponifiable fraction [14] , purification of the unsaponifiable matter by silica solid phase extraction (spe) [15] , and injection into a hplc system equipped with a uv-dad detector and a ms detector [16, 17] . quantification of cholecalciferol was performed by using vitamin d2 as internal standard (is). an aliquot of 35 g of milk was placed in a 100-ml glass bottle, added with 2.36 µg of vitamin d2 as is, 35 ml of a 35% ethanolic solution of koh (in ethanol 85%) and 20 ml of an ethanolic solution of 1% pyrogallol. the bottle headspace was then flushed with nitrogen to remove oxygen. afterwards, the bottle was agitated in the dark for 18 h to allow complete saponification. successively, the unsaponifiable fraction was extracted twice with 35 ml of a mixture of petroleum ether:diethyl ether (90:10, v/v), as suggested in [14] . the ethereal phase was washed 3 times with 30 ml of water until a neutral ph was reached. the ether extract was dried by adding 10 g of anhydrous sodium sulfate, for a total contact time of 60 min at 4 • c. after filtration with a paper filter, the ethereal phase was dried in a rotary evaporator. the unsaponifiable matter was dissolved in 1 ml of n-hexane and stored at −20 • c until analysis. for the determination of vitamin d3, the unsaponifiable matter was purified using silica spe as described in [12] . spe cartridges packed with 500 mg of silica, were used. after cartridge activation with n-hexane (5 ml), the phase was washed with 2 ml of n-hexane:chloroform (22:78, v/v) and vitamin d3 was finally eluted with methanol (2 ml). the methanolic extract was dried under gentle nitrogen flow and the sample was dissolved into a smaller volume of the same solvent. the sample was analyzed by hplc coupled on-line with a uv-dad detector and a ms detector (to confirm the identification of vitamin d3) using the method suggested by sliva et al. [16] and hymøller and jensen [17] , with slight modifications. the hplc system consisted of a quaternary pump varian prostar 240 (palo alto, ca, usa) and a 50-µl loop. the instrument was coupled to an lcq-duo (thermo finnigan, san jose, ca, usa), equipped with an electrospray interface (esi). vitamin d2 (internal standard) and vitamin d3 were identified with positive ionization (esi + ) as their pseudomolecular ions 397.65 m/z and 385.01 m/z, respectively. for quantitative analysis, a photodiode array (pda) detector mod. 330 (varian, palo alto, ca, usa) equipped with an analytical ymc30 column (250 mm × 4.6 mm i.d., 5 µm particle size) (ymc separation technology, dinslaken, germany) packed with a c30 stationary phase, was used. the guard column (10 mm × 4.0 mm i.d.) was packed with the same stationary phase. samples were injected in an isocratic mode, with a methanol:water (96:4, v/v) mobile phase, at a flow rate of 1 ml/min. the injection volume was 50 µl. the wavelength of acquisition was 265 nm and the temperature of both columns was held at 50 • c into a thermostated heater. the detection limit (lod) was 1 µg l −1 milk, while the quantification limit (loq) was 3 µg l −1 milk. lod and loq were calculated as signal-to-noise ratios equal to 3:1 and 10:1, respectively. the extraction of milk lipids was performed according to the iso 14156-2001 idf method [18] . one hundred ml of milk were placed in a 500-ml separating funnel, to which 80 ml of ethanol, 20 ml of ammonia and 100 ml of ethyl ether were added. the funnel was shaken vigorously for 1 min and, when the phases were separated, 100 ml of pentane were added and again stirred gently. once phase separation was achieved, the aqueous fraction was eliminated and the organic phase washed twice with 100 ml of 10% na 2 so 4 solution. the organic phase was then dried with anhydrous sodium sulfate for 10 min; after being filtered, the solvent was first evaporated with a rotary evaporator at 40 • c and thereafter with a slight nitrogen flow. the extracted fat was placed in an oven at 50 • c until a constant weight was attained, and it was then weighed. two replicates for each sample were performed. the data of vitamin d3 and fat content are reported as average values ± standard deviation (st) of two independent replicates (biological replicates). pearson correlation coefficients between fat and vitamin d3 content were calculated using microsoft excel software (version 2010). the hplc/uv-dad chromatogram of the unsaponifiable fraction of hq milk registered at a wavelength of 265 nm [16] , is reported in figure 1 . several components, such as fat-soluble vitamins, sterols and hydrocarbons, make up the unsaponifiable matter of milk, leading to a complex biological mixture. this complexity is clearly shown by the rich chromatographic trace. for this reason, the identification of the analytes of interest was performed with an integrated approach using both a spiking procedure and the identification of vitamin d3 through hplc/ms. to identify vitamin d3 (and vitamin d2, if present), the milk sample was spiked with the pure compounds (central and bottom panel of figure 1 ). it was possible to exclude the presence of vitamin d2 in all the evaluated samples using the spiking procedure. this can be easily verified by comparing the top and central chromatograms of figure 2 , in which the peak of the spiked vitamin d2 is indicated as "b". moreover, vitamin d3, which was naturally present in the milk sample (peak "a" in the top chromatogram), eluted about one minute later than vitamin d2 under the analytical conditions used, thus assuring no peak overlapping. as a second necessary step, vitamin d3 (the "a" peak in the top chromatogram of figure 1 ) was unambiguously identified using hplc/tandem ms (ms 2 ) under the same hplc conditions. the mass fragmentation of the pseudomolecular peak of vitamin d3 is reported in figure 2 . the dissociation of the pseudomolecular peak at m/z 385.01 generates fragments related to the loss of water (385 − 18 = 367), and the contemporary loss of water and the isopropyl side chain (385 − 18 − 42 = 325). it was possible to exclude the presence of vitamin d2 in all the evaluated samples using the spiking procedure. this can be easily verified by comparing the top and central chromatograms of figure 2 , in which the peak of the spiked vitamin d2 is indicated as "b". moreover, vitamin d3, which was naturally present in the milk sample (peak "a" in the top chromatogram), eluted about one minute later than vitamin d2 under the analytical conditions used, thus assuring no peak overlapping. as a second necessary step, vitamin d3 (the "a" peak in the top chromatogram of figure 1 ) was unambiguously identified using hplc/tandem ms (ms 2 ) under the same hplc conditions. the mass fragmentation of the pseudomolecular peak of vitamin d3 is reported in figure 2 the use of an is instead of an external calibration was already reported in an interlaboratory study by staffas and nyman [19] . basically, the sample purification for vitamin d3 is a laborious protocol (sample saponification followed by solvent extraction and spe), thus the loss of the analyte during the procedure cannot be considered constant and a correction factor cannot be determined. the is method was chosen for a simple but crucial reason: since the is was added directly in the milk (at a very early stage), losses along the various steps of the purification procedure were automatically compensated for [20] . in addition, the choice of this analytical approach is further supported by the following facts: (i) vitamin d2 (is) is easily distinguished from the analyte in the hplc trace, as reported in figure 1 ; ii) vitamin d2 exhibits similar chemical properties to vitamin d3, so it is assumed that they undergo a similar loss during sample pretreatment; (iii) the presence of vitamin d2 was excluded in all the evaluated samples; (iv) the extinction coefficient e (1%, 1 cm) at 265 nm is extremely similar for both vitamins d2 and d3 (475 and 480, respectively) [19] . known quantities of ergocalciferol (at three different concentration levels (0.01, 0.03 and 0.06 mg kg −1 )), were added to calculate the vitamin d2 recovery after sample saponification and purification. the average extraction yield was equal to 81.9%, which is within the expected recovery ranges (60the use of an is instead of an external calibration was already reported in an interlaboratory study by staffas and nyman [19] . basically, the sample purification for vitamin d3 is a laborious protocol (sample saponification followed by solvent extraction and spe), thus the loss of the analyte during the procedure cannot be considered constant and a correction factor cannot be determined. the is method was chosen for a simple but crucial reason: since the is was added directly in the milk (at a very early stage), losses along the various steps of the purification procedure were automatically compensated for [20] . in addition, the choice of this analytical approach is further supported by the following facts: (i) vitamin d2 (is) is easily distinguished from the analyte in the hplc trace, as reported in figure 1 ; (ii) vitamin d2 exhibits similar chemical properties to vitamin d3, so it is assumed that they undergo a similar loss during sample pretreatment; (iii) the presence of vitamin d2 was excluded in all the evaluated samples; (iv) the extinction coefficient e (1%, 1 cm) at 265 nm is extremely similar for both vitamins d2 and d3 (475 and 480, respectively) [19] . known quantities of ergocalciferol (at three different concentration levels (0.01, 0.03 and 0.06 mg kg −1 )), were added to calculate the vitamin d2 recovery after sample saponification and purification. the average extraction yield was equal to 81.9%, which is within the expected recovery ranges (60-115%) at the tested concentrations, according to the procedural manual of the codex alimentarius [21] . in addition, the obtained extraction recovery agrees with those reported in other studies, where vitamin d3 in milk was determined with similar analytical methodologies [13, 22] . as a result, vitamin d2 was successfully used as is for the quantification of vitamin d3 in all the samples. table 1 reports the vitamin d3 content expressed as µg l −1 of milk. in phq milk, the vitamin d3 content varied from not detected (<1 µg l −1 ) to 17.0 µg l −1 . only four samples evidenced the clear presence of vitamin d3, while, in the other samples, cholecalciferol was found at trace levels (<3 µg l −1 ), except for one sample where it was absent. in farm samples, the vitamin d3 content ranged from not detected to 12.5 µg l −1 . in this case, only three samples had quantifiable values of vitamin d3, whereas in most samples it was either not detected (n = 10) or present only at trace levels (<3 µg l −1 , n = 9). in the raw milk samples (farm1 and farm2), vitamin d3 was below the quantification limit (<3 µg l −1 ). table 1 also reports the fat content of farm and phq samples and expressed as g 100 ml −1 milk (%). according to the iso 14156:2001 method, the fat content of phq samples ranged from 2.84% to 3.21%, while in farm milk it varied from 2.55% to 4.23%. it is not surprising that the fat content is lower than the legal requirement defined by the italian regulation. it has already been reported [23] that, although this is the official international standardization organization-international dairy federation method for milk lipid extraction, it gives satisfactory results for neutral lipids, but it has important disadvantages in terms of polar lipid losses, such as phospholipids and sphingolipids. thus, it can be assumed that these results are a good approximation of the content of neutral lipids in milk, which also include the unsaponifiable matter containing vitamin d3, since this is a non-polar fraction of the total lipids. the results obtained in the present study agree with those reported in the literature for non-hq milk, which show that the vitamin d3 levels in non-enriched fresh bovine milk, including hq milk, are generally very low. trenerry et al. [24] detected 0.05 µg 100 ml −1 of vitamin d3 in milk (~4.5% fat), while perales et al. [6] found 0.125-1.0 µg l −1 of vitamin d3 in milk. in commercial pasteurized milk, vitamin d3 levels were correlated with the fat content in a previous research [8] . however, in the present study, no correlation between the vitamin d3 content and the fat content measured with the iso method could be deduced from the data reported in table 1 . in other words, many of the analyzed samples had a vitamin d3 level below the quantitation limit (<3 µg l −1 ), despite the relatively high milk fat content, and vice versa. this result was not affected by the fat extraction method, because vitamin d3 is a non-polar lipid component, for which the iso method represents the optimal extraction procedure. in any case, these results also reflect the complexity of the cow physiology, underlying the fact that not all the feed ingredients are bio-accumulated in milk, as many of these components are actually used in the cow metabolism (bones, muscles, cardiovascular apparatus, etc.). in general, vitamin d3 was often more abundant in phq samples than in farm ones; this could be due to the dairy industry practice of mixing the collected hq raw mass milk from the diverse farms to obtain the required fat content without adding any cream or skim milk, as ruled by the italian decree no. 185/1991 [11] . considering that raw milk needs to be boiled before consumption according to the current italian regulation, this might further reduce vitamin d3 content due to its possible thermal degradation and consequent reversible isomerization to pre-vitamin d3 [25] . however, thermal stability of vitamin d is still a controversial aspect, as other studies have proved that vitamin d is heat stable and that pasteurization and sterilization treatments do not promote its degradation [26, 27] . on the other hand, the guidelines for healthful italian food habits published by the italian national institute for research on food and nutrition [28] recommend an average consumption of three 125-ml portions of milk per day, considering an average content of 9 µg/kg of vitamin d3 in hq pasteurized whole milk (equivalent to 135 ui of vitamin d3). this work presents the vitamin d3 content of hq milk (a quality-labeling milk category defined by the italian legislation) for the first time in a scientific publication. it is a survey about the differences in vitamin d3 content between hq raw and pasteurized milk with the aim to monitor a representative even if not exhaustive part of the italian production (particularly from northern italy). although the hq regulation does not provide specific requirements for vitamin d3 in hq milk, the consumer could expect that hq milk contains more vitamin d3 than conventional milk, since hq raw milk must comply with more precise and stricter hygienic and composition requirements, especially in terms of fat content. however, in general, the content of vitamin d3 in hq milk was not higher than conventional milk. in some cases, the vitamin d content of pasteurized hq milk was higher than raw hq milk. since the daily requirement of vitamin d for healthy adults is 600 iu [29] in a balanced diet, it would be highly advisable and useful that the actual content of vitamin d3 in hq pasteurized whole milk were added as nutritional information on the label of the milk package, as a best practice of consumer information policy. the role of vitamin d deficiency in the incidence, progression, and complications of type 1 diabetes mellitus vitamin d: a review on its effects on muscle strength, the risk of fall, and frailty a review of the 2019 novel coronavirus (covid-19) based on current evidence evidence that vitamin d supplementation could reduce risk of influenza and covid-19 infections and deaths rheumatologists' perspective on coronavirus disease 19 (covid-19) and potential therapeutic targets determination of vitamin d in dairy products by high-performance liquid chromatography vitamin d compounds in cows' milk vitamin d metabolites in bovine milk and butter principi di tecnologia del latte e dei derivati ruolo dell'industria mangimistica nella filiera food per la tutela della salute umana regulation concerning the conditions of zootechnical production, the composition and hygienic-sanitary requirements of raw milk intended for use in the production of "high quality fresh pasteurized milk". official gazette of the republic of italy ubiquinone in italian high-quality raw cow milk recent trends in the analysis of vitamin d and its metabolites in milk-a review vitamin d stability in milk a survey of vitamin a and d contents of fortified fluid milk in ontario reverse-phase liquid chromatographic determination of vitamin d in infant formulas and enteral nutritionals vitamin d analysis in plasma by high-performance liquid chromatography (hplc) with c30 reversed phase column and uv detection-easy and acetonitrile-free milk and milk products-extraction methods for lipids and liposoluble compounds; international standard organization determination of cholecalciferol (vitamin d3) in selected foods by liquid chromatography: nmkl collaborative study guidelines for dietary supplements and botanicals; part i, aoac guidelines for single laboratory validation of chemical methods for dietary supplements and botanicals procedural manual of the codex alimentarius commission determination of cholecalciferol (vitamin d3) in bovine milk by dispersive micro-solid phase extraction based on the magnetic three-dimensional graphene-sporopollenin sorbent total milk fat extraction and quantification of polar and neutral lipids of cow, goat, and ewe milk by using a pressurized liquid system and chromatographic techniques the determination of vitamin d3 in bovine milk by liquid chromatography mass spectrometry degradation studies of cholecalciferol (vitamin d3) using hplc-dad, uhplc-ms/ms and chemical derivatization natural vitamin d content in animal products vitamin d3 fortification, quantification, and long-term stability in cheddar and low-fat cheeses linee guida per una sana alimentazione italiana, rev dietary reference intakes for calcium and vitamin d this article is an open access article distributed under the terms and conditions of the creative commons attribution (cc by) license the authors would like to thank andrea borsari from granarolo s.p.a. (bologna, italy) for supplying the milk samples. the authors declare no conflict of interest. the funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results. key: cord-004297-rm0zbgfm authors: hemilä, harri; chalker, elizabeth title: vitamin c may reduce the duration of mechanical ventilation in critically ill patients: a meta-regression analysis date: 2020-02-07 journal: j intensive care doi: 10.1186/s40560-020-0432-y sha: doc_id: 4297 cord_uid: rm0zbgfm background: our recent meta-analysis indicated that vitamin c may shorten the length of icu stay and the duration of mechanical ventilation. here we analyze modification of the vitamin c effect on ventilation time, by the control group ventilation time (which we used as a proxy for severity of disease in the patients of each trial). methods: we searched medline, scopus, and the cochrane central register of controlled trials and reference lists of relevant publications. we included controlled trials in which the administration of vitamin c was the only difference between the study groups. we did not limit our search to randomized trials and did not require placebo control. we included all doses and all durations of vitamin c administration. one author extracted study characteristics and outcomes from the trial reports and entered the data in a spreadsheet. both authors checked the data entered against the original reports. we used meta-regression to examine whether the vitamin c effect on ventilation time depends on the duration of ventilation in the control group. results: we identified nine potentially eligible trials, eight of which were included in the meta-analysis. we pooled the results of the eight trials, including 685 patients in total, and found that vitamin c shortened the length of mechanical ventilation on average by 14% (p = 0.00001). however, there was significant heterogeneity in the effect of vitamin c between the trials. heterogeneity was fully explained by the ventilation time in the untreated control group. vitamin c was most beneficial for patients with the longest ventilation, corresponding to the most severely ill patients. in five trials including 471 patients requiring ventilation for over 10 h, a dosage of 1–6 g/day of vitamin c shortened ventilation time on average by 25% (p < 0.0001). conclusions: we found strong evidence that vitamin c shortens the duration of mechanical ventilation, but the magnitude of the effect seems to depend on the duration of ventilation in the untreated control group. the level of baseline illness severity should be considered in further research. different doses should be compared directly in future trials. in controlled trials, vitamin c has improved endothelial function, lowered blood pressure, increased left ventricular ejection fraction, decreased the incidence of atrial fibrillation, decreased bronchoconstriction, prevented pain, shortened the duration of colds, and decreased the incidence of colds in physically stressed people, and it may also have beneficial effects against pneumonia, see reference [1] . the average person, in good health, maintains normal plasma vitamin c levels with a daily intake of about 0.1 g/day. however, much higher doses, in the order of grams per day, are needed for critically ill patients to reach normal plasma vitamin c levels [2] [3] [4] [5] . without supplementation, plasma vitamin c levels are particularly low in critically ill patients [6] [7] [8] [9] [10] , indicating that the body may have a greater need for vitamin c when under severe stress such as illness requiring intensive care. it seems evident that there are gradual changes in vitamin c metabolism according to the severity of disease, in that the sicker a patient is, the greater the consumption of vitamin c. this further suggests that the sicker a patient is, the more they are likely to benefit from additional vitamin c. given this background, we previously examined whether vitamin c administration has an effect on practical outcomes such as the length of icu stay, without looking at specific medical conditions. from the results of 12 trials with 1766 patients, we calculated that vitamin c reduced the length of icu stay on average by 7.8% (p < 0.001) [1] . we also found that in trials in which the control groups were ventilated for 24 h or more, vitamin c shortened the duration of mechanical ventilation by 18% (p = 0.001) [1] . however, vitamin c did not have an effect on the duration of mechanical ventilation in trials in which control groups were ventilated for less than 24 h, i.e., trials in patients with less severe illness. in this study, we hypothesize that there is a continuous relationship between disease severity and the beneficial effect of vitamin c administration. we used metaregression to analyze the gradual relationship between the effect of vitamin c in the treatment group and the duration of mechanical ventilation in untreated patients of the control group, which we used as a proxy for the severity of the disease. we included controlled trials that compared the length of mechanical ventilation between vitamin c and control groups. we included trials in which the administration of vitamin c was the only difference between the study groups; trials that administered other therapies as well as vitamin c were included only if the other therapies were the same for both trial groups. we did not limit our search to randomized trials and did not require placebo control. we included all doses and all durations of vitamin c administration. we searched medline, scopus, and the cochrane register on 13 nov 2019 with the search phrases described in fig. 1 . we had previously searched the same databases for trials on vitamin c and icu length of stay on 20 jan 2019 [1] ; from that search, we found trials that were not well indexed and so not identified in our new search specifically for trials on vitamin c and mechanical ventilation. finally, we perused the reference lists of the selected trials and relevant reviews, from which we discovered two more trials. we identified nine trials satisfying our selection criteria [11] [12] [13] [14] [15] [16] [17] [18] [19] . we did not include two further trials that reported "ventilator-free days" since we were unable to convert this to our outcome of interest, "duration of mechanical ventilation" [20, 21] . tanaka et al. administered vitamin c continuously with a dosage of 66 mg/kg/h for the first 24 h only, with the reported mean weight of patients being 57 kg [17] . thus, we the searches were carried out on 13 nov 2019. the searches identified nine trials that we included in our systematic review analysis [11] [12] [13] [14] [15] [16] [17] [18] [19] and eight of them were included in our meta-analysis [11] [12] [13] [14] [15] [16] [17] [18] calculated that the average dose was 90 g/day in the tanaka trial. zabet et al. administered 25 mg/kg every 6 h, but the mean weight was not reported [18] . assuming a mean weight of 60 kg, we estimated that the average dose was 6 g/day in the zabet trial. we use these estimates in our text. the outcome in this analysis is the length of mechanical ventilation, which we analyzed on the relative scale. the relative scale is usually more informative than the absolute scale for the analysis of treatment effects on continuous outcomes, in particular, for the analysis of duration data [1, [22] [23] [24] . we used the ratio of means (rom) to estimate the effect of vitamin c, and the taylor series-based approach to calculate the log(rom) [22] . we pooled the selected trials with the metagen function of the meta package of the r statistical software [25] [26] [27] , using the inverse variance, fixed effect options. for metaregression, we used the metareg function of the meta package. we used the χ 2 test and the i 2 statistic to assess statistical heterogeneity among the trials in the metaanalysis [28] . values of i 2 range from 0% to 100%. a value close to 0% indicates very low-level heterogeneity. a value of more than approximately 50% indicates moderate heterogeneity, and a value over 75% indicates highlevel heterogeneity. our calculations are described in additional files 1 and 2. nine controlled trials have reported on vitamin c administration and the length of mechanical ventilation (table 1 ; see additional file 1: table s1 for further details of the trials). the flow diagram of our search is shown in fig. 1 . the total number of patients was 975, with 810 patients in six cardiac surgery trials, 128 patients in two sepsis trials, and 37 patients in one trial with burns patients (table 1 ). vitamin c was administered orally in four trials and intravenously in five trials. the tanaka [17] trial administered 90 g/day, whereas the other seven trials administered from 1 to 6 g/day. safaei et al. [15] and tanaka et al. [17] administered vitamin c on a single day only, six trials administered for 2-5 days [11-13, 16, 18, 19] , and one administered "until icu discharge" for septic shock patients [14] . there is a 250-fold variation in the average length of mechanical ventilation in the untreated groups from 2 h [16] to 511 h [17] , which reflects great variation in the severity of the baseline medical condition (table 1) . six trials were randomized [11-13, 15, 18, 19] , two used alternative allocation [14, 17] , and one did not describe the allocation method [16] . the reported baseline variables for the treatment groups were balanced in all trials (additional file 1: table s1 ). the risk of bias assessment of the trials is shown in fig. 2 . four trials used an explicit placebo [11, 16, 18, 19] . the trial by sadeghpour et al. [19] had a high dropout rate, with 500 participants recruited, but results were reported for just 290 participants [1] . we did not include this trial in our statistical models, but the results are presented separately. in our standard meta-analyses, we pooled the results of the trials on the relative scale, calculating the ratio of means the trials are listed by the number of patients (n). the mean age in the trials ranged from 42 to 64 years, with a median of 60 years. the proportion of males varied from 58% to 75%. five trials were carried out in iran [12, 13, 15, 18, 19] , two in egypt [14, 16] , one in the usa [11] , and one in japan [17] . for detailed descriptions of the trials, see additional file 1: table s1 . the amini trial [12] results are modified as described previously [1] *estimated vitamin c dose, see the "methods" section **sadeghpour et al. [19] recruited 500 participants but reported the results for just 290 participants [1] . because of the high dropout rate (42%), we did not include this trial in our calculations, but we overlay the findings in fig. 4 iv intravenous, po per oral, rom ratio of means [22] : e.g., for the bjordahl trial [11] , rom = 0.86, based on 28.8/33.6, and rom = 0.86 indicates that ventilation time in the vitamin c group was 14% shorter than in the placebo group (rom) [22] . for example, in the bjordahl trial [11] , the length of mechanical ventilation was 28.8 h in the vitamin c group and 33.6 h in the placebo group, which corresponds to rom = 0.86 (28.8/33.6) ( table 1 ). this represents a 14% shorter ventilation time in the vitamin c group. over the eight included trials with 685 patients in total, vitamin c shortened the length of mechanical ventilation on average by 14% (p = 10 −5 ) (fig. 3) . however, there was highly significant heterogeneity in the vitamin c effect between the trials with i 2 = 83% (p = 4.8 × 10 −7 ). this indicates that the calculated average effect of 14% is not consistent over all the included trials. in a meta-regression analysis, we found that the heterogeneity between the trials was explained by the length of mechanical ventilation in the untreated control group (fig. 4) . the evidence for modification of the vitamin c effect by the untreated ventilation time was very strong (p = 10 −7 ). there is little residual heterogeneity around the regression line with i 2 = 12% (p = 0.3), which indicates that the meta-regression in fig. 4 much better captures the findings of the trials compared with the standard meta-analysis shown in fig. 3 . the confidence intervals of all included trials are consistent with the regression line in fig. 4 . the habib [14] trial contributed considerable weight to the effect of vitamin c in fig. 4 . however, even if both the habib [14] and tanaka [17] trials are excluded, there is strong evidence from the six remaining trials that the effect of vitamin c is modified by the ventilation time in the untreated control group (p = 0.004) (see additional file 1). figure 4 indicates that no meaningful benefit from vitamin c is expected for patients whose ventilation time is shorter than 10 h. on the other hand, the regression line in fig. 4 predicts that for patients ventilated for 100 h, vitamin c reduces the ventilation time on average by 31% (rom = 0.69). three trials administered vitamin c orally and five intravenously, but both methods are consistent with the single regression line in fig. 4 . tanaka et al. [17] used by far the highest dose of vitamin c, 90 g/day. figure 4 indicates that the substantial benefit observed in that trial may be explained by the particularly sick patients with burns requiring very long ventilation, rather than by the very high vitamin c dose. we found that vitamin c shortened the length of ventilation on average by 25% (p = 10 −10 ) when the tanaka trial was excluded and the analysis was restricted to the five trials with dosage from 1 to 6 g/day for patients ventilated for over 10 h [11, [13] [14] [15] 18] . the sadeghpour trial [19] is not included in our statistical models because of the high dropout rate, but the results are shown in fig. 4 by the dashed line and they are consistent with the findings of the other trials. our meta-regression analysis above was restricted to studies in which vitamin c was administered as the only difference between the study groups. we did not carry out a systematic search for trials on the combination of vitamins c and e, but in our search for fig. 2 risk of bias summary. review authors' judgments about each risk of bias item for each included trial. a green plus sign (+) indicates that there is no substantial concern for bias in the particular quality item. a question mark (?) indicates that conclusions are unable to be drawn regarding potential bias. a red minus sign (−) indicates that there is an explicit concern regarding bias. in the sadeghpour trial, the dropout rate was very high (42%), justifying the minus sign [1] . the reference numbers to the trials are shown in table 1 the vitamin c trials, we found three trials that administered vitamins c and e together to critically ill patients [29] [30] [31] . given that our search for vitamin c also identifies any combinations of vitamins c and e, it is unlikely that there are many more combination trials. as a secondary analysis, we compared the findings of the three vitamin c and e trials with our meta-regression model based on the eight trials using vitamin c alone (fig. 5 ). nathens et al. administered 1 g/day vitamin c intravenously and 1000 iu/day vitamin e enterally [29] . the duration of mechanical ventilation in the control group was 110 h, for which our model predicts a 32% decrease in the vitamin c group. the observed decrease in the vitamins c and e group was 20% (95% ci 13% to 26%). crimi et al. administered 0.5 g/day vitamin c and 400 iu/day vitamin e enterally [30] . ventilation time in the control group was 213 h, for which our model predicts a fig. 3 effect of vitamin c on the duration of ventilation. the horizontal lines indicate the 95% ci for the vitamin c effect and the blue squares in the middle of the horizontal lines indicate the point estimate of the effect in the particular trial. the red diamond shape indicates the pooled effect and its 95% ci. the sadeghpour trial [19] is not included in the meta-analysis, since the dropout rate was high (42%) [1] . rom ratio of means [22] [19] is not included in the statistical model, since the dropout rate was high; however, it is overlaid here for information. for calculations, see additional file 2. rom ratio of means [22] 37% decrease in the vitamin c group. the observed decrease was 30% (95% ci 0% to 61%). howe et al. administered 1 g/day vitamin c and 1000 iu/day vitamin e enterally [31] . ventilation time in the control group was 456 h, and our model predicts a 42% decrease in the vitamin c group. the observed decrease was 47% (95% ci 7% to 87%). in all three vitamin c and e trials, the observed effect of treatment was quite close to the effect predicted by the trials using only vitamin c (fig. 5 ; see additional files 1 and 2 for the calculations). there is significant variation in the severity of disease in patients who are mechanically ventilated. one measure of severity is the mechanical ventilation time required by the patient, which we used as a proxy for severity. in this study, we found that the duration of ventilation in the untreated control group explained most of the variation in the reported effects of vitamin c on the mechanical ventilation time. in the standard meta-analysis, there is high-level heterogeneity with i 2 = 83% (fig. 3) , whereas in the meta-regression of the vitamin c effect by the control group duration of ventilation, the residual heterogeneity is small with i 2 = 12% (fig. 4) . some of the included trials examined elective surgical patients. these patients are not usually critically ill; however, as a result of their surgery, they are routinely ventilated in the icu for a period of time. in the metaregression, such patients are located on the left-hand side of fig. 4 which means that the analysis takes into account the low level of illness severity. in contrast, the inclusion of patients with less severe disease in the standard meta-analysis decreases the average effect of vitamin c, so that the greater effect on the sicker patients is masked (fig. 3) . the substantial benefit observed in the tanaka [17] trial seems to be explained by the particularly long mechanical ventilation in the untreated control patients (which reflects the greater illness severity), rather than the particularly high vitamin c dosage of 90 g/day in that trial. all the other trials used 6 g/day or less, but there is no evidence that the benefit was less than in the tanaka trial when taking into account the ventilation time in the untreated control group (fig. 4 ). there are a few reports of deaths caused by intravenous vitamin c in doses of 80 to 224 g/day [32, 33] . therefore, the interpretation that the benefit in the tanaka trial may be caused by the type of patients and not by the very high vitamin c dose is important for planning further trials. our previous analysis of the length of icu stay also found that the effect of vitamin c appeared greater for the sicker patients. the length of icu stay was reduced by 10.1% (p = 0.0001) in patients who required an icu stay of 3 days or longer, but by just 5.7% (p = 0.03) in those who needed only 1-2 days in the icu [1] . there are also other findings that are consistent with vitamin c having a greater effect on patients with more severe medical conditions. a meta-analysis of vitamin c effect on exercise-induced bronchoconstriction found that vitamin c halved fev 1 decline caused by exercise [34] . the constant relative effect indicates that the absolute effect was greatest for patients who had the greatest bronchoconstriction in the exercise test. finally, a trial the results of the three trials [29] [30] [31] and their 95% cis are shown. for calculations, see additional file 2. rom ratio of means [22] with common cold patients indicated that the bronchodilatory effect of vitamin c was most beneficial for those with the greatest bronchial hypersensitivity to histamine [35, 36] . there is much evidence indicating that vitamins c and e have an interaction in vitro and in vivo [37] [38] [39] [40] [41] , and three trials have examined the effect of the combination of vitamins c and e on the duration of mechanical ventilation [29] [30] [31] . the reported effects from the three trials are largely consistent with the meta-regression model based on the eight trials using vitamin c alone (fig. 5) , though the confidence interval of the nathens et al. trial does not cross the regression line. thus, the statistically significant benefit observed in each of these three trials might be explained by the long ventilation time in the control groups, indicating greater severity of illness in the patients, rather than by the addition of vitamin e to the intervention. to test the possible additional benefit of vitamin e over vitamin c would require 2 × 2 factorial trials. although our meta-regression analysis by the ventilation time in the control group explains the heterogeneity in the published trials, it seems evident that other variables influence the effects of vitamin c. for example, there are indications that treatment effects can differ between less and more developed countries. panagiotou et al. identified several studies that reported greater treatment effects in less developed countries than in more developed countries [42] . although methodological variations may explain some of the differences, there can also be genuine treatment differences between substantially different cultures, since wealth is strongly correlated with life-style factors including nutrition and with differences in hospital treatments. previously, vitamin c was found to prevent post-operative atrial fibrillation in non-us trials, but not in us-based trials [43] , which may also indicate that the effects of vitamin c can depend on cultural context. thus, although the fit of the meta-regression line in fig. 4 is good, the findings should not be extrapolated directly to other contexts. two recent meta-analyses concluded that vitamin c is not beneficial for critically ill patients [44, 45] , whereas a third concluded that vitamin c was beneficial for sepsis patients [46] . however, all three meta-analyses included studies that administered vitamin c in combination with numerous other substances, such as vitamins a, b, and e, selenium, and zinc [47] [48] [49] . such trials do not test the specific effect of vitamin c. the other substances can have negative or positive effects, and they can also modify the effect of vitamin c. the three meta-analyses also had statistical shortcomings [47] [48] [49] . our current metaanalysis was restricted to trials that tested vitamin c alone. a fourth recent meta-analysis concluded that vitamin c shortens ventilation time in cardiac surgery patients [50] ; however, the study was shown to contain several substantial statistical errors [51] . in systematic reviews, one potential concern is publication bias, in that negative trials may remain unpublished. however, publication bias cannot realistically generate the close association shown in fig. 4 . to explain this association by publication bias would require that positive studies with less ill patients remain unpublished, and negative studies with severely ill patients also remain unpublished. five trials did not use an explicit placebo [12] [13] [14] [15] 17 ], but we do not consider that the lack of placebo undermines the validity of those trials, since icu patients receive numerous treatments and it is unlikely that one additional tablet or infusion would cause a substantial placebo effect for ventilated patients. the lack of a placebo may cause bias in research on subjective outcomes, but less so on objective outcomes [52] . thus, it is unlikely to bias studies with outcomes such as the duration of mechanical ventilation. it may not be worthwhile to carry out further research on the effects of vitamin c on mechanical ventilation for patient groups that require on average less than 10 h of ventilation. the level of sickness severity should be taken into account in future studies, for example, by evaluating prognostic scores at the start of the trial. our analysis did not find differences between oral and intravenous vitamin c, but oral administration is rarely an option for the sickest patients, for whom the effects of vitamin c appear greatest. our analysis is not informative about the optimal dosage of vitamin c. future trials should directly compare different dosage levels. supplementary information accompanies this paper at https://doi.org/10. 1186/s40560-020-0432-y. additional file 1 calculations; table s1 . detailed description of the included trials. additional file 2. the data set used in this analysis. authors' contributions hh and ec planned the study and searched the literature and selected the trials to be included. hh entered the data into a spreadsheet and carried out the statistical analysis. ec checked that the entered data were consistent with original reports. hh wrote the draft manuscript and ec participated in the critical revision of the manuscript. both authors read and approved the final manuscript. availability of data and materials descriptions of the included trials, and the risk of bias assessment, and the analyzed data are available as additional files 1 and 2. vitamin c can shorten the length of stay in the icu: a meta-analysis ascorbic acid dynamics in the seriously ill and injured early postoperative substitution procedure of the antioxidant ascorbic acid metabolic clearance of the antioxidant ascorbic acid in surgical patients vitamin c pharmacokinetics in critically ill patients: a randomized trial of four iv regimens total vitamin c, ascorbic acid, and dehydroascorbic acid concentrations in plasma of critically ill patients ascorbyl radical formation in patients with sepsis: effect of ascorbate loading metabolic origin of hypovitaminosis c in acutely hospitalized patients massive and long-lasting decrease in vitamin c plasma levels as a consequence of extracorporeal circulation hypovitaminosis c and vitamin c deficiency in critically ill patients despite recommended enteral and parenteral intakes perioperative supplementation with ascorbic acid does not prevent atrial fibrillation in coronary artery bypass graft patients selenium, vitamin c and nacetylcysteine do not reduce the risk of acute kidney injury after off-pump cabg: a randomized clinical trial effect of oral vitamin c on atrial fibrillation development after isolated coronary artery bypass grafting surgery: a prospective randomized clinical trial early adjuvant intravenous vitamin c treatment in septic shock may resolve the vasopressor dependence comparative effect of grape seed extract (vitis vinifera) and ascorbic acid in oxidative stress induced by on-pump coronary artery bypass surgery ascorbic acid versus magnesium for the prevention of atrial fibrillation after coronary artery bypass grafting surgery reduction of resuscitation fluid volumes in severely burned patients using ascorbic acid administration: a randomized prospective study effect of high-dose ascorbic acid on vasopressor's requirement in septic shock impact of vitamin c supplementation on postcardiac surgery icu and hospital length of stay medical respiratory intensive care unit nursing, fisher bj, natarajan r. phase i safety trial of intravenous ascorbic acid in patients with severe sepsis effect of vitamin c infusion on organ failure and biomarkers of inflammation and vascular injury in patients with sepsis and severe acute respiratory failure: the citris-ali randomized clinical trial ratio of means for analyzing continuous outcomes in meta-analysis performed as well as mean difference methods many continuous variables such as the duration of the common cold should be analyzed using the relative scale duration of the common cold and similar continuous outcomes should be analyzed on the relative scale: a case study of two zinc lozenge trials r project for statistical computing meta: an r package for meta-analysis. r news measuring inconsistency in meta-analysis randomized, prospective trial of antioxidant supplementation in critically ill surgical patients the beneficial effects of antioxidant supplementation in enteral feeding in critically ill patients: a prospective, randomized, double-blind, placebo-controlled trial mechanical ventilation antioxidant trial ascorbic acid-induced hemolysis in g-6-pd deficiency oxalate nephropathy after continuous infusion of high-dose vitamin c as an adjunct to burn resuscitation vitamin c may alleviate exercise-induced bronchoconstriction: a meta-analysis effect of ascorbic acid on increased bronchial responsiveness during upper airway infection vitamin c and common cold-induced asthma: a systematic review and statistical analysis interaction of vitamin c and vitamin e during free radical stress in plasma: an esr study ascorbic acid spares alpha-tocopherol and prevents lipid peroxidation in cultured h4iie liver cells combined deficiency of vitamins e and c causes paralysis and death in guinea pigs faster plasma vitamin e disappearance in smokers is normalized by vitamin c supplementation modification of the effect of vitamin e supplementation on the mortality of male smokers by age and dietary vitamin c comparative effect sizes in randomised trials from less developed and more developed countries: meta-epidemiological assessment vitamin c for preventing atrial fibrillation in high risk patients: a systematic review and meta-analysis vitamin c administration to the critically ill: a systematic review and meta-analysis the effect of vitamin c on clinical outcome in critically ill patients: a systematic review with meta-analysis of randomized controlled trials evidence is stronger than you think: a meta-analysis of vitamin c use in patients with sepsis misleading meta-analysis on vitamin c and critically ill patients b8accd32dfc accessed 5 statistical problems in a meta-analysis on vitamin c and critically ill patients misleading meta-analysis on vitamin c for sepsis patients 0d89ad26d7 accessed 5 effects of vitamin c on organ function in cardiac surgery patients: a systematic review and meta-analysis vitamin c for cardiac surgery patients: several errors in a published meta-analysis. comment on "effects of vitamin c on organ function in cardiac surgery patients: a systematic review and meta-analysis is the placebo powerless? an analysis of clinical trials comparing placebo with no treatment publisher's note springer nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations ethics approval and consent to participate not applicable; this is a meta-analysis of studies already published. the authors declare that they have no competing interests. key: cord-322899-uxvlagt3 authors: gorji, ali; ghadiri, maryam khaleghi title: the potential roles of micronutrient deficiency and immune system dysfunction in covid-19 pandemic date: 2020-11-06 journal: nutrition doi: 10.1016/j.nut.2020.111047 sha: doc_id: 322899 cord_uid: uxvlagt3 preliminary studies indicate that a robust immune response across different cell types is crucial in the recovery from covid-19. an enormous number of investigations point to the vital importance of various micronutrients in the interactions between the host immune system and viruses, including covid-19. there are complex and multifaceted links between micronutrient status, the host immune response, and the virulence of pathogenic viruses. micronutrients play a critical role in the coordinated recruitment of innate and adaptive immune responses to viral infections, particularly in the regulation of pro-and anti-inflammatory host responses. furthermore, inadequate amounts of micronutrients not only weaken the immune system in combating viral infections, but also contribute to the emergence of more virulent strains via alterations of the genetic make-up of the viral genome. this study aimed to evaluate the evidence which suggests the contribution of micronutrients in the spread as well as the morbidity and mortality of covid-19. both the presence of micronutrient deficiencies among infected subjects and the effect of micronutrient supplementation on the immune responses and overall outcome of the disease could be of great interest to weigh the use of micronutrients in the prevention and treatment of covid-19 infection. these investigations could be of great value in dealing with future viral epidemics. coronaviruses (cov) are a large group of rna viruses that primarily target the human respiratory system and can lead to a wide range of illnesses from the common cold to severe respiratory syndromes. in the last two decades, outbreaks of cov-related infections, including the severe acute respiratory syndrome (sars)-cov and the middle east respiratory syndrome (mers)-cov, led to great public health problems and concerns. [1] a new coronavirus termed covid-19 is currently associated with an increasing number and rate of morbidities and fatalities. the genetic analysis of the covid-19 exhibited more than 50% sequence identity to mers-cov and 80% to sars-cov. [2] the innate immune system represents the first line of defense against viruses, which can inhibit virus replication, improve virus clearance, promote tissue repair, and activate a prolonged adaptive immune response against the viruses. [3] viruses, such as cov, could affect the function of the immune system in different manners, such as dysregulation of the macrophage antiviral response, induction of excessive cytokine-mediated immune system responses, and the activation of complement and coagulation cascades, which may result in enhanced infectivity and worse outcomes. [4] since there is currently no effective drug or vaccine, boosting the immune system could be a reasonable option to combat covid-19. a functional immune system is a prerequisite for the host's ability to prevent or limit viral infections. it is well-known that the nutrition of the host may influence the immune system and its susceptibility to viral infection. numerous studies pointed to the increase in either susceptibility to or severity of various viral infections in the nutritionally deficient subjects. [5] in addition to the host's response, various micronutrients can have a significant influence on disease severity via the modulation of viral pathogenesis, such as mutations in the viral genome. [6] on the contrary, a viral pathogen in the micronutrient deficient population could replicate to a new, more pathogenic strain. [7] the objective of this review was to provide a collection of evidence points to the key role of various micronutrients on the interactions between the host immune system and viruses, particularly coronaviruses. furthermore, we describe the evidence that may support the contribution of micronutrient deficiency and immune system dysfunction to the viral outbreaks, including covid-19. references for this review were identified through searches of pubmed for articles published from january 1961 to april 2020, by use of the terms "coronavirus", "immune system", "micronutrients", "vitamin", and "covid-19". relevant articles were identified through searches in google scholar and springer online archives collection. articles resulting from these searches and relevant references cited in those articles were reviewed. articles indicate a strong link between viral infections; particularly cov infection, with micronutrients and the immune system were selected. articles published in english and spanish were included. the recruitment of various immune cells, including antibody-secreting cells and follicular helper t cells as well as activated cd4 + and cd8 + t cells, along with igm and igg covid-19-binding antibodies have been reported in a patient with non-severe covid-19. [8] in the initiation stage of severe covid-19, increased amounts of pro-inflammatory cytokines and chemokines, like interleukin-2 (il-2), il-6, granulocyte-colony stimulating factor, interferon (ifn) γ-induced protein 10, monocyte chemoattractant protein-1, vascular endothelial growth factor, macrophage inflammatory protein-1α, and tumor necrosis factor-α (tnf-α), as well as lymphopenia have been detected in the serum of some patients. however, infection with covid-19 in its critical stage exacerbates the secretion of t-helper-2 (th2) cytokines, such as il-4, il-1ra, and il-10, which suppress the inflammatory response [9, 10] . the preliminary data indicate the ability of the immune system to recognize covid-19 and initiate an effective immune response across different cell types leading to successful recovery from the infection in cases with mild-to-moderate symptoms. the majority of subjects with covid-19 only have mild-to-moderate symptoms. however, the cytokine storm aggravates the infection severity and worsens prognosis. [9, 10] poor outcomes with enormously high values of pro-inflammatory cytokines have been also reported in patients infected with mers-cov and sars-cov. [11] in addition, it has been suggested that a significantly elevated amount of platelets in patients with covid-19, which is associated with a longer average hospitalization and poor prognosis, may be stimulated by the higher inflammatory cytokine levels. [12] baseline total lymphocytes were significantly higher in survivors than non-survivors. in survivors, lymphopenia improved during hospitalization, whereas severe reduction of lymphocytes continued to decrease until death in non-survivors. the values of serum ferritin and il-6 were markedly greater in non-survivors than survivors. [13] due to the supporting role of micronutrients on the host immune responses to viral infections (table 1) , it is not surprising if micronutrient deficiency would be associated with a weakened immune system and a higher risk for the occurrence and severity of viral infections. zinc homeostasis is essential for sustaining proper immune function. [14] zinc plays an important role in host-virus interactions due to its effect on nucleic acid synthesis and repair, apoptosis, inflammation, and redox homeostasis. [15] zinc baseline level is a crucial factor that can affect antiviral immunity, especially in zinc-deficient populations. [16] zinc deficiency is associated with impaired immune responses and leads to a higher risk of respiratory viral infections, particularly in elderly subjects. [17] zinc is involved in the modulation of the pro-inflammatory response by targeting nuclear factor kappa b (nf-κb). zinc deficiency enhances the production of pro-inflammatory cytokines, such as il-1β, il-6, and tnf-α, and reduces the lytic activity of natural killer (nk) cells. furthermore, zinc deficiency leads to a decrease in antibody production via the alteration of the function and number of various immune cells. [14] the zinc-finger domain is found in various proteins encoded by the genome of different cov, such as sars-cov [18] , and plays a key role in viral replication and transcription. [19] a specific mutation within the zinc-finger domain of cov caused reduced antiviral response. [20] disruption of the zinc-binding function of cov-229e nonstructural protein-13 (nsp13) or deletion of the entire zinc-binding domain affects both transcription and replication of cov. [21] furthermore, it has been shown that the zinc-binding domain may start to unfold during the first transition of sars-cov and lead to a reduction in pathogen virulence. selenium deficiency not only weakens the host immune system against viral infections but also leads to viral genome mutations from benign variants to highly pathogenic viruses. [4] inadequate antioxidant protection against various mutating rna viruses, including sars-cov, has been observed in subjects with blood selenium concentrations of less than 1 μm/l. iodide modulates the transcriptional immune signature of human peripheral blood immune cells and induces greater cytokine and chemokine secretion, such as il-6, il-8, and il-10. [36] iodide is found in the salivary glands, nasal mucosa, and lung secretions. [37] the sodium-iodine symporter, a plasma membrane glycoprotein that mediates active iodide transport in different tissues, contributes to the oxidation of iodide in the lungs, which improves the antiviral respiratory defense system. [38] the oral intake of potassium iodide copper is an essential nutrient for the development and maintenance of the human immune system. copper is crucial for the generation and response of il-2 to adaptive immune cells, the production of antibodies, maintaining intracellular antioxidant balance, and self-protection of immune cells. [41, 42] copper deficiency can lead to increased viral virulence, decreased il-2 level and t-cell proliferation, and reduced phagocytic ability. [43] copper exhibits a potent antiviral property, possibly via binding electron donor groups on viral proteins or nucleic acids. [44] copper antiviral effects may also due to the regulatory roles of copper on certain enzymes, which are critical for the function of various types of immune cells. [42, 43] in addition, activated macrophages accumulate copper within the phagosome to inactivate the pathogens. this event plays an important role in the control of pulmonary infections. [45] intravenous copper administration results in a greater copper concentration in the lung [46] , promotes the anti-inflammatory forkhead box p3-positive t-cells. [59] vitamin a deficiency leads to the reduced weight of the thymus, decreased lymphocyte proliferation, impaired tcell-mediated response, and enhanced pathogen binding to respiratory epithelial tissues. [60] vitamin a inhibits viral replication, promotes the immune response, and decreases morbidity and mortality of some viral infections. [61] the beneficial effects of vitamin a on morbidity and mortality of some viral infections, such as measles and hiv, could be due to increased antibody production and lymphocyte proliferation as well as enhanced t-cell lymphopoiesis. [62] clinical investigations and in vitro studies have indicated that vitamin a is the main regulator of mucosal immunity and could affect immune responses to mucosal infections. levels as well as an enhancement of cd4 + /cd8 + ratio and tnf-α value. [41] there are several experimental and clinical studies indicating the antiviral effects of b vitamins. patients with hiv suffered from a high prevalence of vitamin b1 deficiency. vitamin b1 affects hiv infection via non-genomic mechanisms, which may lead to beneficial effects in patients with hiv. [72] vitamin b2 alone or in combination with uv light has a potent antiviral effect on a wide range of viruses, such as mers-cov. [73] deficiencies in vitamins b6, b9, and b12 render people more susceptible to viral respiratory infections, such as influenza. [74] it has been suggested that a vitamin a-vitamin b6 conjugate analogue can exert an antiviral effect by regulating transcription and/or replication of various rna viruses, including coronavirus. [75] vitamin c a wide range of studies points to the importance of vitamin c in immune host responses to viral infections. vitamin c promotes the production, function, and migration of immune cells, and enhances serum values of antibodies and complement proteins. [76] vitamin c also supports the differentiation and proliferation of lymphocyte and enhances apoptosis, chemotaxis, and ifn production. [77] clinical trials and experimental studies suggested that vitamin c inhibits the pro-inflammatory cytokines, like tnf and il-6, and increases the proinflammatory cytokines, such as tnf, il-6, and il-1β. [78] vitamin c exerts an antiviral immune response against the influenza virus via the enhancement of ifn-il-1α/β production. [79] vitamin c enhances the resistance of broiler chicks [80] and chick embryo tracheal organ cultures [81] to infections induced by an avian coronavirus. vitamin c reduced the cytokine levels (tnf-α and il-1β) in an animal model of acute respiratory distress syndrome (ards); suggesting its beneficial effect for the treatment of similar inflammatory disorders. [82] indeed, the intravenous administration of vitamin c in patients suffering from sepsis and ards significantly reduced the mortality rate. [83] several investigations have suggested that vitamin c in high dosages has direct virucidal effects. [84] several clinical trials have shown a significantly lower incidence of rti in vitamin c-treated subjects. [85] on the contrary, vitamin c deficiency enhances the risk of respiratory infections, particularly in the elderly. vitamin d deficiency was associated with higher illness severity, multiple organ dysfunctions, and mortality in critically ill subjects, particularly with sepsis and pneumonia. vitamin e supports the integrity of epithelial membranes and increases il-2 production, nk cell activity, t-cell-mediated functions, and lymphocyte proliferation. furthermore, vitamin e initiates t-cell activation, promotes th1 proliferation, and inhibits th2 response. [101] vitamin e supplementation causes a higher il-2 and ifn-γ production with a lower lung virus titer in animals with the influenza virus. [102] vitamin e deficiency markedly increases the viral pathogenicity and heart damage in mice infected with coxsackieviruses-b3. [103] administration of vitamin e increased lymphocyte proliferation as well as il-2 and ifnγ production in healthy subjects and aged mice after influenza infections. [102] a modest level of vitamin e supplementation regulates the cellular free radical-antioxidant balance, enhances the antibody response, and activates the immune cells of broilers vaccinated with the infectious bronchitis virus. [104] h1n1-infected mice have shown positive associations between anti-inflammatory cytokine il-10 level and vitamin e metabolism. [105] vitamin e and selenium exhibit strong control over viral replication and mutation. in a nutritional deficiency condition of these micronutrients, rna viruses are able to convert to more virulent strains. [106] vitamin e deficient mice failed to exhibit an appropriate immune response to hsv-1 infection. [107] a significant increase in lung and serum vitamin e levels has been observed a few days after infection with the influenza virus in mice. [108] critically ill patients who were admitted to an icu with ards have shown a significant reduction of vitamin e plasma level. [109] the use of vitamins e and c in critically ill patients reduced the incidence of ards and pneumonia and shortened icu length of stay. [110] the most vulnerable groups to the severe-critical complications of covid-19 are the elderly above the age of 60 and subjects with chronic diseases, including hypertension, diabetes, and cardiovascular or respiratory diseases. [111, 112] although only 36% of patients infected with covid-19 in italy were over the age of 70, more than 80% of deaths occurred in people of this age. [113] furthermore, older adults are more susceptible to severe covid-19 at admission. [114] immune function in older adults can be modified by nutritional and pharmacological interventions. [115] aging causes alterations in every component of the immune system, which leads to increased morbidity and mortality following infectious diseases. [116, 117] the altered function of the immune system in the elderly can be promoted via the manipulation of cytokine production, changes of metabolic pathways in immune cells, and immune-system rejuvenation aimed at reactivating the generation of new lymphocytes. [118] micronutrient interventions have shown a promising impact in targeting the immune system impairments observed in the elderly and improve the infection-related morbidity and mortality. [119, 120] micronutrient deficiencies affect approximately two billion people worldwide and contribute essentially to the global burden of several diseases. [121] for instance, zinc deficiency affects approximately 30% of the world population with ranging from 4% to 73% across different countries and implicated in about 16% of lower rti. [122] micronutrient deficiencies decrease the ability to resist infections and are common causes of immunodeficiency in the developing countries. [123] although micronutrient deficiencies are one of the major public health challenges in developing countries, about 30% of the population in industrialized societies are also affected. [124] silent epidemics of micronutrient deficiencies could be due to insufficient intake and/or sufficient intakes in association with impaired absorption owing to infection, inflammation, or chronic diseases. [123, 125] approximately 35% of populations who are above the age of 50 in europe, usa, and canada have an obvious deficiency of one or more essential micronutrients. [126] in addition to an insufficient intake of micronutrients, older people lose their ability to produce endogenous antioxidants. [127] italy, spain, and france have experienced the highest covid-19 death toll in europe and the elderly in these countries have shown the highest prevalence of vitamin d deficiency compared with many other european countries. [128, 129] approximately 60% of people who died from covid-19 in italy were living in the lombardy region. during the cold seasons, up to 60-90% of the population in this region shows deficient/insufficient values of vitamin d. [130] the lombardy region, the most air polluted area of italy, has a high rate of hospitalizations and respiratory illnesses. [131] air pollution associated with increased ozone values absorbs uvb radiation and leads to vitamin d deficiency. [132] the overall prevalence of low vitamin d status is above 40% in the us population. [133] several clinical studies indicate the vital role of micronutrients in the prevention and treatment of viral infections. [134, 135] micronutrient deficiencies, including zinc and vitamins b2, b6, b12, c, and d, were reported to be common in the ecuadorian elderly, which weakened their immune system and placed them at greater risk of viral rti. [74] administration of zinc and vitamin a significantly decreased the incidence of pneumonia in children with pneumonia [136] , and oral zinc supplementation could shorten the duration of symptoms of respiratory infection. [137] food and agriculture organization of the united nations has reported that nutrition and antiviral drugs are equal in the treatment of hiv infection and regular intake of micronutrients is crucial for promoting the immune response and maintaining good health for both infected and uninfected individuals. [138] early administration of vitamin a reduced the mortality rate of patients with ebola virus disease during the western african outbreak. [139] supplementation of micronutrients in elderly subjects enhanced the number of t-cells and lymphocytes, improved lymphocyte response to mitogen, increased il-2 levels and nk cell activity, promoted the response to the influenza virus vaccine, and reduce the duration of viral diseases. [41, 140] some commonly used drugs, such as antibiotics, can lead to various micronutrient depletions, such as iron and vitamins a, b, and d. [141] a combination of micronutrient supplementation in older adults may decrease antibiotic usage and causes a higher post-vaccination immune response. [126] interestingly, some countries with higher morbidity and mortality of covid-19, such as italy and spain, have a greater consumption of antibiotics compared to other european countries. [142, 143] mice treated with antibiotics are unable to stimulate cytokine release in the lung and augment protective t-cell responses following influenza infection. [144] infectious disease outbreaks could indeed be the result of infection by a virus whose virulence has altered as a result of replicating in a nutritionally deficient host so that a non-virulent virus becomes a pathogen due to changes in its genome. in addition, available data strongly suggest that the association of unpredictable occurrence of novel viral pathogens combined with decreased host immunity and micronutrient deficiency poses a twofold threat to human health in the near future. further investigating the role of micronutrients and their substitution on immune system activity, therefore, may present a highly cost-efficient and uncomplicated measure with promising long-term benefits on future viral outbreaks. the development of novel vaccinations and drugs targeting pathogens that cause currently relevant diseases is often an expensive and risky process associated with a narrow spectrum efficacy due to their selective applications. furthermore, the use of novel vaccines and drugs is usually restricted to the global population due to their high costs. a decade ago, the copenhagen consensus project on hunger and malnutrition concluded that efforts to provide micronutrients for the global population generate higher returns than any other public health measure. 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weight gain the authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. key: cord-311965-3x3tjzhi authors: alexander, jan; tinkov, alexey; strand, tor a.; alehagen, urban; skalny, anatoly; aaseth, jan title: early nutritional interventions with zinc, selenium and vitamin d for raising anti-viral resistance against progressive covid-19 date: 2020-08-07 journal: nutrients doi: 10.3390/nu12082358 sha: doc_id: 311965 cord_uid: 3x3tjzhi objectives: the novel coronavirus infection (covid-19) conveys a serious threat globally to health and economy because of a lack of vaccines and specific treatments. a common factor for conditions that predispose for serious progress is a low-grade inflammation, e.g., as seen in metabolic syndrome, diabetes, and heart failure, to which micronutrient deficiencies may contribute. the aim of the present article was to explore the usefulness of early micronutrient intervention, with focus on zinc, selenium, and vitamin d, to relieve escalation of covid-19. methods: we conducted an online search for articles published in the period 2010–2020 on zinc, selenium, and vitamin d, and corona and related virus infections. results: there were a few studies providing direct evidence on associations between zinc, selenium, and vitamin d, and covid-19. adequate supply of zinc, selenium, and vitamin d is essential for resistance to other viral infections, immune function, and reduced inflammation. hence, it is suggested that nutrition intervention securing an adequate status might protect against the novel coronavirus sars-cov-2 (severe acute respiratory syndrome coronavirus-2) and mitigate the course of covid-19. conclusion: we recommended initiation of adequate supplementation in high-risk areas and/or soon after the time of suspected infection with sars-cov-2. subjects in high-risk groups should have high priority as regards this nutritive adjuvant therapy, which should be started prior to administration of specific and supportive medical measures. the novel coronavirus sars-cov-2 (severe acute respiratory syndrome-coronavirus-2), causing covid-19, is by far the most dangerous coronavirus ever identified, capable of infecting not only animals, but also humans across the globe. the severity of the covid-19 pandemic has dramatically surpassed the prevalence of acute respiratory syndrome coronavirus (sars-cov) and middle east respiratory syndrome coronavirus (mers-cov), which were distributed to more limited regions in 2003 and 2012, respectively. a single-stranded rna comprises the genomic structure of sars-cov-2 [1] . in severe cases, covid-19 is accompanied by excessive activation of the innate immune system with progressive inflammation and a cytokine storm from activated cells, particularly in the airways [2] , leading to the cytokine release syndrome [3, 4] . unfortunately, in spite of their anti-inflammatory effects, corticosteroids have been observed to worsen the clinical status of patients with sars or related virus infections [5, 6] . use of convalescent plasma has been tried as a possible approach, but the experiences with this strategy are limited [7] . except for the use of convalescent plasma, there is at present no approved treatment or vaccine for covid-19. therefore, it is an urgent need for public health measures, not only to limit the spread of the virus, but also to implement preventive approaches to alleviate severe covid-19, e.g., by reduction of the excessive inflammation. the metabolic status of the host, as influenced by advanced age, current medical condition, and lifestyle, appears to determine the clinical severity of covid-19 [8] . in critically ill patients, coexisting diseases include type 2 diabetes, hypertension, and heart disease [9] . the elderly are more prone to severe respiratory infection than young people, apparently due to connections between old age and deficient nutrition and immunity [10] . clinical and subclinical micronutrient deficiencies common in older adults are known to contribute to decreased immune function and age-related diseases [11] , implying that nutritional management is essential to reduce the risk of severe infection [12] . in view of a lack of clinical data on preventive and/or therapeutic efficiency of the nutritive adequacy of selenium, zinc, and vitamin d in covid-19, we, in the present narrative review, discussed recent clinical data on the role of these micronutrients in the protection against bronchopulmonary infections, as well as the existing indications of their impact on covid-19. although the status of other nutrients, such as vitamins c and a, may also play a role, they were not focused upon in the present article. we did a literature search for the period 2010-2020 on pubmed, medline, and google scholar with the keywords of sars, sars-cov-2, covid 19, coronavirus, micronutrients (zinc, selenium, vitamin d), immune system, inflammation, prevention, and treatment. based on the information retrieved, we here discussed the role of the nutritional status of certain trace elements and vitamin d in the perspective of principles for implementing preventive measures against rna viruses. clinical or subclinical micronutrient deficiencies, such as deficiencies of zinc, selenium, and vitamin d, which frequently occur in old age groups, contribute to age-related diseases including diabetes, hypertension, and coronary heart disease [13] [14] [15] . these diseases, which in a substantial fraction of the cases are related to the metabolic syndrome [16] , are characterized by signs of low-grade inflammation, which may also result from ageing [17] . pre-infectious signs of inflammation, such as elevated values for crp (c-reactive protein), represent a common aggravating factor in covid-19 [9] . adequacy of zinc, selenium, and vitamin d is essential for adequate immunocompetence, which to some extent may counteract an inflammatory aggravation. dietary advice alone may not be sufficient to secure adequacy for these nutrients in certain conditions, including in elderly subjects [18] , involving the need for supplements in susceptible segments of populations. being an essential component of numerous enzymes, such as superoxide dismutase 1 and 3 [19] , the trace metal zinc is important for the development and maintenance of immune and other cells [20] . zinc deficiency is known to result in dysfunctional humoral and cell-mediated immunity [21] . in the elderly, low zn status (serum zn values <0.7 mg/l) has been found to represent a risk factor for pneumonia [22] . long-term zinc deficiency is known to increase inflammations and inflammatory biomarkers [23] . most facets of the immune system are affected by zinc deficiency, particularly the t-cell function. zinc deficiency also drives a th17 response, which is associated with increased inflammation [24] . in elderly subjects, reduced concentrations of circulating zinc correlated with increased levels of the cytokines il-6 (interleukine-6), il-8, and tnf-α (tumour necrosis factor-α) [25] . in a case report, four covid-19 outpatients 26-63 years of age were treated with lozenges of zinc salts [26] . they took the lozenges several times each day, up to doses between 115 to 184 mg zn/day for 10 to 14 days, and all of these patients recovered. in another case report, three covid-19 patients 38-74 years of age with additional gut manifestations received zinc sulphate (220 mg zn daily for 5 days), together with hydroxychloroquine and azithromycine [27] . the latter patients recovered. being case reports, it was not possible to conclude on the efficacy of zinc. with regard to other infectious diseases, many studies show that zinc status may impact the outcome. several randomized control trials (rcts) showed that zinc given during an acute episode of diarrhea reduces the duration and risk of persistent disease [28] . the world health organization therefore changed their recommendations for the treatment of childhood diarrhea to include oral zinc medication. zinc also plays a role in acute respiratory infections [29] . routine zinc supplementation reduces the incidence of acute lower respiratory infections in young children in low-and middle-income countries [30] . several recent studies used zinc as an adjunct treatment for lower respiratory infections, although with mixed results [31] . in one large rct from india enrolling young infants with signs of severe bacterial illness, it was investigated whether zinc could reduce the risk of treatment failure [32] . the authors found that children assigned to the zinc group had a 40% reduction in treatment failure and mortality compared with the placebo group. many rcts examined the role of zinc supplementation in common colds, the results from these showing that, when given early in the illness, zinc had the potential to reduce the duration by 1 to 3 days [33] [34] [35] . furthermore, a positive effect of zinc supplementation was observed in several studies on hepatitis c, which is induced by infection with a single-stranded rna virus [36] . in this context, it is of interest that raising the intracellular concentration of zinc with zinc-ionophores like pyrithione or chloroquin could directly reduce the replication of a variety of rna viruses in cells in vitro through inhibition of their rna polymerase activity [37] . combined administration of zinc and pyrithione, even at low concentrations, inhibited the replication of sars coronavirus (sars-cov) in vitro [38] . consequently, zinc supplement may have effects, not only on the covid-19-associated over-active inflammation, but presumably also on the sars-cov-2 agent itself [39] . as for the preventive doses used, it was noted that, on a long-term basis, an intake ≤25 mg/day was recommended, as a high intake of zinc may disturb copper balance [40] . selenium is an essential trace element for mammalian redox biology by occurring as selenocysteine in catalytical centers of many selenoproteins [41, 42] . an adequate supply of the amino acid serine is required for the synthesis of selenocysteine, which is incorporated into selenoproteins [43] . nutritional deficiencies of selenium may impact, not only the immune response, but also the pathogenicity of a virus [44] [45] [46] . of note, a recent study from china reported an association between the cure rate of cov-2-infected patients and selenium status, as deduced from city population hair selenium from cities outside hubei, reflecting regions with poor and adequate selenium intakes [44] . in a study, selenium status (selenium and selenop) were significantly higher in surviving covid-19 inpatients (n = 27) compared with non-survivors (n = 6) [45] . further studies with control of confounding and clinical trials are necessary to confirm this association. of particular interest is the finding that a main protease of sars-cov-2 responsible for the viral replication, interacts with the essential seleno-enzyme glutathione peroxidase1 (gpx1) [46, 47] , which is strongly dependent on adequate selenium supply. it is notable that the gpx mimic ebselen (a synthetic selenium compound) is a potent inhibitor of the sars-cov-2 main protease [48] . bioinformatic screening of the sars-cov-2 gene signatures provided further evidence of protein interactions and antisense transcript mrna-mrna interactions occurring at selenocysteine-related insertions in rna viruses [49] . dietary selenium deficiency, together with increased oxidative stress in the host, can alter a viral genome from a normally mildly pathogenic virus into a highly virulent agent after its entrance into the host, which occurred with the coxsackie 3b virus in keshan disease in a selenium-deficient area in china [50] . it was proposed that se deficiency could play a substantial role in the genesis of sars-cov [51] . the potential protective effect of selenium is explained by its role as an essential cofactor in a group of enzymes that, in concert with vitamin e, works to reduce the formation of reactive oxygen species (ros). ros in excess may trigger oxidative changes both in invading microorganisms and in the cells in the host [52] . a failing antioxidant defense might also be accompanied by an exaggerated inflammatory response in the host, even in the absence of an active infection [53] . among the most potent antioxidative selenoenzymes are the glutathione peroxidases (gpxs) and the thioredoxin reductases (txnrds), which need an intake of at least 100 µg se/day to function optimally. other selenoproteins, i.a., selenoprotein k (selenok) and selenoprotein s (selenos), also appear to play a role in the regulation of immune responses [54] . in a variety of infectious diseases selenium appears to play a significant role in protecting the respiratory system, in particular toward viral infections [54] . beck et al. found that se deficiency significantly increased the susceptibility to influenza-induced lung pathology associated with the overexpression of pro-inflammatory cytokines [55] . an analogous effect was observed in benign coxsackie virus infection, which resulted in the development of myocarditis in se-deficient mice [56] . these findings corresponded to the observation of lower interferon-γ (ifn-γ) and tnf-α levels, as well as reduced survival rate in se-deficient mice infected with the influenza virus as compared to se-adequate controls [57] . in turn, selenium treatment was shown to up-regulate the expression of genes for interferons (ifn-α, ifn-β, and ifn-γ) in response to the avian influenza (h9n2) virus [58] . in older adult humans, se treatment was shown to modulate response to the influenza vaccination, being accompanied by increased ifn-γ levels after vaccination [59] . therefore, selenium supplementation to populations with suboptimal status has been considered a safe adjuvant therapy in preventive measures against viral infections [60] . the selenium status varies widely between different areas in the world. compared with levels in northern america [61] , selenium levels in populations in large parts of europe are well below a threshold of about 100 µg/l required for adequate expression of selenoproteins. the insufficient selenium intake is caused by low selenium content in soil and, consequently, in cereals and other food plants, as well as in fodder for grazing farm animals [41, 62] . the optimal function of the gpxs also depends upon adequate intracellular levels of the cofactor glutathione (gsh), explaining the importance of adequate intakes of proteins containing the sulfur component of this tripeptide, viz. cysteine or methionine. reduced gsh is associated with senescence in several species, including humans [63] . apparently healthy elderly people in the age group 60-79 had significantly lower erythrocyte gsh than younger individuals [64] . moreover, individuals with chronic diseases, including hypertension, have a deficit of the active form of gsh [65, 66] . in cases of marginal intakes of sulfur amino acids, supplementation with acetylcysteine will restore intracellular gsh levels, which is of crucial importance in bronchial and pulmonary cells [67] . n-acetylcysteine is already an approved and extensively used drug in obstructive bronchitis [68] , and it has proven beneficial against severe influenza infection [69] . administration of glutathione has been shown to relieve dyspnea associated with covid-19 pneumonia [70] . another factor co-operating with selenoenzymes appears to be coenzyme q 10 (coq 10 ). in a swedish randomized placebo-controlled study, healthy elderly subjects low in selenium were given selenium supplementation combined with coenzyme q 10 . this supplementation was shown to reduce the non-specific inflammatory response as measured by plasma crp [71] and other biomarkers of inflammation [53] , and also cardiovascular mortality [72] . as severe coronavirus infections are characterized by an overactive inflammation, this relief in inflammatory response by optimizing the selenium status is of considerable interest [62] . it is also relevant that coq 10 supplements, even when given alone, can exert an anti-inflammatory effect [73] . an anti-inflammatory effect of exogenous coq 10 may appear clearer in old age when its endogenous production is significantly reduced [74] . selenium treatment given alone, without combination with acetylcysteine or coq 10 , in critical ill patients admitted to the intensive care unit (non-septic and septic patients) has been used [75] . in patients with advanced infections, manzanares and coworkers [76] , in a meta-analysis, did not find a consistent beneficial effect on mortality, but, in a subgroup analysis, they found a reduction in the infections in non-septic patients. when considering the positive effects of selenium on immune regulation and inflammation in populations low in selenium, it appears justified to conclude that an adequate pre-infectious status of selenium would represent a protective measure against the hyperinflammation characterizing corona viral infections. thus, in subjects with suboptimal status (plasma selenium <100 µg/l), supplementation at a dose of 100-200 µg se/day, with or without cofactors, to achieve rapid saturation of vital selenoproteins, should represent an adjuvant approach to prevent aggressive sars-cov-2 infection. however, a total long-term intake of selenium from food and supplements ≤300 µg se/day is recommended, as higher intakes may be associated with toxicity [77] . it is well-known that cholecalciferol (vitamin d3) can be synthesized from cholesterol in the body skin upon exposure to sunlight. its biological activity is dependent on successive hydroxylations by the liver and the kidneys to 1,2-(oh) 2 -d3, which binds to vitamin d receptors. beyond its roles in calcium homeostasis and the maintenance of bone integrity, it also stimulates the maturation of immune cells. epidemiological studies suggested an inverse association between circulating levels of 25(oh)-d3, a biomarker of vitamin d status, and inflammatory biomarkers, including crp and il-6 [78] . suboptimal levels of vitamin d, particularly at the end of the winter season, have been reported in a substantial number of otherwise healthy adults [79] . people with limited access to sunlight, and elderly with reduced synthesizing capacity, may have vitamin d deficiency [80] . vitamin d has been suggested to play a role in covid-19, as two ecological studies indicated that the rate of infection was higher in countries at higher latitudes and/or lower vitamin d status [81, 82] . in a non-peer-reviewed study from los angeles, vitamin d deficiency was identified as a risk factor for positive covid-19 tests [83] . a recent study on covid-19 inpatients (n = 134) found that a significantly smaller fraction of patients in intensive care units had 25-oh-d above 50 nmol/l (19%) compared with those in conventional medical wards (39.1%) [84] . in a non-peer-reviewed study from cincinnati, the authors found associations between vitamin d deficiency and hospital admission, disease severity, and also with death, among patients from primary care and specialized clinics (n = 691) [85] . vitamin d was shown to be an essential factor for protection against respiratory infectious diseases [86] . severe vitamin d deficiency is frequently seen in critically ill patients and appears to be related to poor prognosis [87] . in older patients, severe vitamin d deficiency has been considered an independent predictor for community-acquired pneumonia [88] , being also associated with increased risk of admission to an intensive care unit [89] , and associated with mortality [90] . moreover, vitamin d deficiency is shown to be associated with aggravation of lung inflammation, leading to acute respiratory distress syndrome (ards) with respiratory epithelium damage and hypoxia [91] . an inverse association between 25-oh-cholecalciferol levels and risk of acute respiratory failure in critically ill patients has been observed, being most convincingly significant for subjects with 25-oh-cholecalciferol <25 nmol//l [92] . increasing experimental data on cells in vitro demonstrated beneficial effects of vitamin d as to pathogenetic mechanisms of respiratory viral infections. thus, vitamin d treatment was shown to reduce respiratory syncytial virus (rsv) and rhinovirus (rv) replication in epithelial cells through enhancement of virus-induced interferon-stimulated genes [93] and synthesis of the antiviral protein ll-37 [94] . treatment with 1,25(oh)-d improved respiratory-induced antiviral immune response to rv infections characterized by up-regulation of il-8 and cxcl-10 (c-x-c motif chemokine ligand 10 also known as interferon gamma-induced protein 10) production [95] . in addition, it was demonstrated that vitamin d is capable of reducing inflammatory response without alteration of antiviral activity and viral clearance in airway epithelial cells infected with rsv [96] . furthermore, in view of high incidence of lung fibrosis as a characteristic sequela of covid-19 [97] , it is important to note that vitamin d prevented a tgf-β1-induced profibrotic phenotype of lung cells [98] . however, no preventive effect of vitamin d supplementation on pneumonia was observed in three independent case-control studies [99] , but the interpretation of these results should take into account the apparent lack of pre-existing vitamin d deficiency. furthermore, the benefit of vitamin d replacement in an advanced stage of critical illness is controversial, as some studies do not show a benefit when it is administered late in the critical disease [100] . vitamin d status can easily be determined as 25-oh-cholecalciferol in plasma. it follows that, in case of low status, <50 nmol/l in plasma, vitamin d supplementation (40 µg d 3 /day) could work as an approach for prevention of an aggressive course of the inflammation induced by this novel coronavirus. as for the preventive doses used, it is recommended that, on a long-term basis, the intake of vitamin d should be ≤100 µg d3/day to avoid hypercalcuria with risk of renal stones, and also hypercalcemia [101] . the direct evidence that the micronutrients zinc, selenium, and vitamin d might be involved in the course and outcome of the covid-19 disease is observational and weak. however, based on experiences from treatments of sars and other viral infections, we here underscored observations showing that nutritive supplements administered at an early stage of the infection were important for enhancing host resistance against rna viral infections, which might also include severe covid-19. we hypothesized that, in particular, increased resistance toward escalation of covid-19 into the life-threatening cytokine release syndrome might be obtained (figure 1 ). the nutritional status of the host has yet not been considered a crucial factor in severe viral infections, because the efficacy of nutrient supplementation when administered at the stage of advanced illness has been disappointing. nevertheless, it is conceivable that a good nutritional status, if achieved in vulnerable population segments before escalation of the disease, would have immuno-enhancing and anti-inflammatory effects [102] . we are aware of the alleged therapeutic role of megadoses of vitamin c (6-8 g/day) in viral infections [103, 104] , but, as this would be a pharmacological approach, we did not further discuss this in the present article. we considered the proposed intervention with, i.a., proteins and multivitamin solutions, given immediately after hospital admission to relieve the covid-19 infection [105] to represent an interesting modification of our approach. however, further research and clinical trials are requested both on therapeutic and preventive roles of nutritive supplements. based on the available literature, a reasonable presumption is that the pre-infectious status of zinc, selenium, and vitamin d might be of especial importance for the resistance against a progressive course of covid-19. our recommendations are early outpatient nutritional intervention in sars-cov-2 exposed or high-risk subjects, preferably before specific and supportive treatment. it is tempting to suggest that that early nutritional interventions will be of particular significance for vulnerable segments of populations in developing countries. such an approach is simple, cheap, and harmless. while high doses of the micronutrients might be needed to restore deficiencies, it is advisable to follow recommended upper tolerable intake levels for long-term intakes of the micronutrients. parallel to any of the nutritional approaches, controlled studies on the efficacy of anti-viral and anti-inflammatory measures are of importance. to obtain general 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innlandet hospital trust, norway, is acknowledged for support. key: cord-285641-y5ianyqi authors: bamji, mahtab s.; murty, p. v. v. s.; sudhir, parimala diana title: nutritionally sensitive agriculture—an approach to reducing hidden hunger date: 2020-10-01 journal: eur j clin nutr doi: 10.1038/s41430-020-00760-x sha: doc_id: 285641 cord_uid: y5ianyqi cereal-based diets of the people in developing countries are qualitatively deficient in micronutrients—vitamins and minerals—due to low intake of vegetables, fruits, legumes and foods of animal origin. consumption of nutritious millets has also come down in india. calorie sufficiency may ensure protein sufficiency (though not protein quality), but it does not ensure adequacy of micronutrients. studies in several countries in asia, and india show that with education and advocacy even farmers with small and marginal land holdings can be persuaded to raise homestead vegetables and fruits gardens and increase household vegetables consumption. backyard poultry also has good acceptance and impact on household egg consumption. for best results, the community, especially the mothers have to be educated about the importance of nutrition for health and wellbeing. studies done by the authors in the villages of medak district, of the south indian state of telangana, show remarkable improvement in the knowledge of food, nutrition, hygiene and health of mothers with children under 3 years of age, with education–behavioural change communication. impact of nutrition gardens and backyard poultry with high egg-yielding breeds had positive impact on the household consumption of vegetables and eggs. developing countries like india are facing a double burden of diseases. while pre-transition diseases like infectious diseases and malnutrition persist, there is growing incidence of post-transition non-communicable diseases like obesity, hypertension, diabetes, cardiovascular diseases and cancer. india has become the diabetes capital of the world. nutrition influences both the burdens. malnutrition increases susceptibility to infections and resultant morbidity and mortality. prenatal malnutrition has been shown to affect the growth of the foetus resulting in low birth weight (lbw) babies. intra-uterine malnutrition epigenetically alters body composition with higher fat deposition, which in turn predisposes the individual to adult-onset non-communicable diseases. (barker's hypothesis, foetal origins of adult diseases) [1] . who has recognised diet as one of the important determinants of health. the 2019 eat-lancet commission report has compared the food consumption patterns in india, from different income groups, regions and sectors (rural/urban), with the eat-lancet reference diet and highlighted the deviations [2] . national sample survey office 2011-2012 data were used for comparison since this is the most recent countrywide data. except for the richest 5%, of indians, the average daily intake of calorie of indians was below the recommended 2503 kcal/capita/day. the consumption of fruits, vegetables legumes, meat, fish and eggs were significantly lower. the share of calories from protein sources was only 6-8%, compared to 29% in reference diet. though the deficits were higher in the lowest decile of consumption expenditure, even the rich indian households do not consume adequate quantities of vegetables, fruits and noncereal protein foods. these findings are akin to those of the national nutrition monitoring bureau surveys in india, which show that the cereal-based indian diets are deficient in the consumption of micronutrient-rich foods like vegetables, fruits, legumes and animal products [3] . thanks to schemes such as subsidised sale of rice and wheat to families below the poverty line (bpl), through the public distribution system, the consumption of traditional millets has also come down. millets are rich in fibre, many bcomplex vitamins and minerals. the predominantly cerealbased diets have resulted in rampant qualitative deficiency of micronutrients particularly, vitamins a, b2, b6, b12, folic acid, c and minerals like iron, zinc and calcium. while calorie adequacy may ensure protein adequacy (though not protein quality), it most often fails to quench the hidden hunger. a recent study from the national institute of nutrition, hyderabad, india, shows a high prevalence of vitamin deficiencies, particularly, vitamins a, b2, b6, b12, folic acid and vitamin d, assessed by subclinical status (blood values) and dietary intakes, in an apparently healthy urban adult population [4] . the overall prevalence of anaemia was 21%. vitamin deficiencies as judged by blood levels were: vitamin a 6% (despite much higher dietary deficiency), d 29%; b1 11%; b2 50%; b6 46%; folate 32% and active b12 46%. vitamin d deficiency has become a major problem even in tropical countries. the dietary intake of all the vitamins except vitamins b1 and b6 were close to or lower than 20% of indian reference. that of vitamin b12 was only 4% and folate 6%. vitamin c was not examined. the study population had high incidence of overweight and obesity, and high levels of homocysteine-an independent risk factor for cardiovascular diseases for whose metabolism b vitamins like folic acid and b12 are required. this shows that even the apparently well-fed indians from middleincome group suffer from vitamin deficiencies. mineral status was not examined. the three basic strategies for combating micronutrient deficiencies are: (i) supplementation with micronutrients (the pharmacy-based approach), (ii) food fortification and (iii) dietary diversification-a farm-based approach [5] . crop biofortification through conventional breeding, marker-assisted molecular breeding, or genetic engineering, is the technological approach to enrich the germ plasm with specific micronutrients [6, 7] . this strategy is generally used to combat severe deficiency of one or two nutrients. india has two micronutrient supplementation programmes [8] . (1) national nutrition anaemia prophylaxis programme. in this programme, all pregnant and lactating women receive 60 mg of elemental iron and 500 µg of folic acid (ifa tablets daily) for at least 100 days during pregnancy and 100 days in post-partum period. preschool children receive 20 mg of elemental iron plus 100 µg of folic acid daily. due to administrative infirmities and lack of awareness regarding the importance of the programme desired results have not been obtained. education of the community to ensure compliance is very necessary for such programmes to succeed. in 2013, the ministry of health and family welfare, india, launched the national iron plus initiative (2013). (2) massive dose vitamin a supplementation programme to prevent nutrition blindness. in this programme, first dose of 100,000 iu of vitamin a is given to children at 9 months of age along with measles vaccine. this is followed by biannual dose of 200,000 iu to children between the ages of 18 and 59 months. blindness due to vitamin a deficiency has become rare all over the world, but subclinical vitamin a deficiency (serum vitamin a < 20 µg/dl) due to dietary deficiency persists. opinion among nutrition scientists in india is divided about the need for the vitamin a supplementation programme. its continuation is however needed at least in areas where signs and symptoms of vitamin a deficiency like night blindness and bitot spots persist. the ultimate effort should be to increase the dietary intake of vitamin a and its plant precursor β carotene. food fortification is done either to restore nutrients lost during processing or to enrich foods with nutrients. food fortification has been defined as 'addition of one or more essential nutrients to a food, whether or not it is normally contained in the food, for the purpose of preventing or correcting a demonstrated deficiency of one or more nutrients in the population or specific population groups' [9, 10] . it is a convenient and relatively less expensive strategy with a wide outreach and has been used for nutrients like vitamins a, d and some b-complex vitamins and minerals like iron and zinc. the vehicle to be used for fortification should be a food that is consumed by large segments of population regardless of economic status including poorest of poor, and the bioavailability and stability of the fortified nutrients should be good. one of the successful programmes in india is salt fortified with iodine, which has now become a universal programme. the national institute of nutrition, hyderabad, india, has developed salt double fortified with iodine and iron. its use at present is limited. fat soluble vitamins are often added to oils. wheat flour is often fortified with minerals and b-complex vitamins, and who/fao has provided guidelines for it [6] . fortifying oil with vitamins a and d is mandatory in many countries, including india. the subject of food-based approach including nutrition sensitive agriculture for better nutrition outcomes has been recently reviewed [5, [11] [12] [13] . this review discusses some of the studies in india and other asian countries on nutritionally sensitive farming to combat micronutrient deficiencies. thanks to the green revolution, india has become selfsufficient in the production of cereals like wheat and rice [14] . production of millets and pulses has however missed the green revolution, but in recent years this shortcoming is being corrected. india ranks among the top two countries in the world for production of milk (white revolution) and vegetables and fruits (rainbow revolution). even the egg production has gone up markedly. despite this, the dietary intake of these income-elastic foods remains low in all segments of population, particularly among the poor, due to lack of awareness regarding nutritional importance of these foods and high cost. even the farmer who produces them prefers to sell them rather than consume at home, because for resource poor farmers with small or marginal land holdings, income is more important than health and nutrition security. importance of income cannot be denied. behavioural change communication (bcc) is needed to stress the importance of dietary diversification to ensure food and nutrition security. high post-harvest losses add to the problem in developing countries, where facilities for cold storage, and processing are inadequate [14] . agriculture is generally viewed as a source for income and export-at best to meet calorie and protein requirement. the problem of micronutrient deficiencies (hidden hunger) is not understood. unfortunately, the subject of human nutrition is not in the syllabus of agriculture universities, and hence agriculture extension workers fail to understand the need for leveraging agriculture for nutrition security. the subject of nutrition is also very weakly covered if at all in medical syllabus. one of the earliest studies on homestead vegetables and fruits gardening (term, used to indicate gardens next to the home or in farms) for micronutrient security was aimed at improving the intake of provitamin a, β carotene. it was conducted by the national institute of nutrition, hyderabad, india, in the villages of andhra pradesh, india, and the all india institute of hygiene and public health, calcutta, west bengal, india [15, 16] . seeds and saplings of vegetables rich in β carotene (green leafy vegetables (glv), orange and yellow vegetables and fruits) were given to farmers and farmers advised to grow them near their home or in their farms. apart from technical knowhow about growing the plants, food and nutrition education was given. in both the centres there was marked increase in the number of families growing β carotene-rich vegetables and fruits, their consumption and improvement in understanding of the problem of vitamin a deficiency, foods rich in vitamin a and signs (bitot spots, xerophthalmia) and symptoms (night blindness) of vitamin a deficiency. calcutta centre reported reduction in the prevalence of bitot spots but in hyderabad centre the results were equivocal. there was some reduction in the common belief that pregnant women should avoid eating papaya since it causes abortion. hellen keller international has supported an extensive programme of improved homestead gardens and backyard poultry in bangladesh, cambodia, nepal and philippines to increase the production and household availability of micronutrient-dense vegetables and fruits and eggs. nutrition education formed an important part of the strategy [17] [18] [19] [20] . a significant increase in consumption of vegetables and eggs by mothers and children was recorded, mothers' knowledge of nutrition also improved. bangladesh and philippines observed reduction in the prevalence of anaemia. similar reduction was not seen in cambodia and nepal. families' income also showed some increase through sale of farm produce. ms swaminathan foundation in chennai, india, is currently exploring the food system for nutrition model in few villages of wardha district of vidarbha region of maharashtra, and koraput district of odisha, india [21] [22] [23] . community nutrition gardens were also tested. the components of the model are: (1) survey to identify the major nutritional problems, (2) design context-specific suitable agricultural interventions to address the local nutritional problems, (3) improve small farm productivity and profitability, (4) undertake nutrition awareness programmes and build a cadre of hunger fighters and (5) introduce monitoring systems for assessing impact on nutrition outcomes. location specific vegetables and fruits that are rich in mn are introduced in homestead gardens. professor m. s. swamiathan advocates genetic gardens for nutrition security [22] . recent evaluation of the impact of this strategy on household food consumption showed remarkable increase in the monthly consumption of fruits and vegetables-frequency as well as quantity, as seen from a baseline survey in 2014 and end-line survey in 2017 of a sample of 190 households in each location [23] . though the authors mention, health and nutrition education as part of the intervention, no data on its impact are given in the sited paper. urban gardens for food and nutrition related outcomes are yet another promising strategy. it was recently reviewed in [24, 25] . for nutrition security there has to be awareness and access at affordable cost to balanced diet and correct feeding practices (food security,) safe drinking water, disease-free environment and health care outreach. this will ensure absorption also. over the past two decades, the authors (msb and pvvsm) have tried to develop strategies for each of these in select villages of medak district in the south indian state of telangana (formerly part of andhra pradesh). (see www.dangoriatrust.org.in.) this narrative will be confined to the experience with homestead gardens and backyard poultry to enrich the household diet with micronutrient-rich foods. three studies have been conducted in different sets of villages of medak district in the south indian state of telangana (formerly andhra pradesh). the population of the selected villages ranged between 1000 and 3000. most households had small or marginal landholding, own or leased. water source for farming was ground water-bore wells or rain-fed. though water stressed, paddy and sugarcane were the main crops. in dry season, maize or sorghum were grown. maize was sometimes intercropped with red gram (cajuns cajan). only few families raised vegetables. all the households were bpl and eligible for the indian government's subsidy schemes including subsidised food grains through public distribution system. most families belonged to the hindu backward class category. there were a few muslim households. some villages had tribal settlements called tandas attached to them. all households had proper houses, and access to bore well water. in the past few years, government has sponsored two-pit household latrine construction. so now most households have a latrine and claim to use it when asked. technological intervention was combined with robust, food, nutrition, sanitation and health education to bring about behavioural change [26] [27] [28] . in the first study, march-april 2007 to march-april 2010 [26] , 15 villages from four mandals (geographical area) were included. all families interested to raise vegetable and fruit gardens were invited to join. in the subsequent two studies (march-april 2007-2010, and september 2014 to april-may 2018) covering eight to ten villages (population about 12,000-15,000); families with pregnant women and preschool children were specifically targeted. however, a family approach was used, and husbands often came for training in farming and poultry technologies ( [26, 27] and proceedings of ivth agricultural science congress, new delhi, india-under publication). seeds of a variety of glv (amaranth-amaranthus gangeticus; ambat chuka-rumex vesicarius; corrriander-coriandrum sativum; fenugreek-trigonella foenum-graecum; 'gogu'-hibiscus, cannabinus; spinach-spinacia oleracea), and other vegetables like broad beans-vicia faba; cluster beans-cyamopsis tetragonoloba; french beans-phaseolus vulgaris; tomatoes-lycopersicon esculentum; ladies finger (okhra)-abelmoschus esculentus and saplings of curry leaves-murraya koenigii; drumstick-moringa oleifera and malabar spinach (bachali)-basella alba were distributed to the target households. glv are very rich in all micronutrients, are easy to grow and need relatively less water. some variety or other can be grown throughout the year. beans are rich in proteins, besides micronutrients. they can fix nitrogen and enrich the soil with nitrogen. fruit plants like guava-psidium cattleyanum; mango-magnifera indica; papaya-carica papaya and lime-citrus aurantifolia were selectively given to families who had assured source of water and performed well. papaya and mangoes are rich in β carotene (provitamin a) and vitamin c and guava in vitamin c. farmers grew vegetables like brinjal (eggplant) and gourds out of choice. few households had one or two trees of plants like papaya, mangoes, guava, drumstick (moringa) and curry leaves prior to intervention. interested women were taught to raise saplings of plants like papaya, drumstick and bachali (basella alba, a creeper). the saplings were purchased from them for distribution. each woman raised 50-100 saplings, and earned some money. organic methods of farming like vermicomposting and botanical pesticides-decoction of chilli-garlic paste or neem seed, were also taught to reduce the use of chemical fertilisers and pesticides, mostly the latter. centralised meeting (at the dct campus) and decentralised meetings (hands-on training in the villages) were given. help from subject specialists in agriculture/horticulture was taken as resource persons for conducting the training programmes. cooking demonstrations to teach simple foods for complementary feeding were held by involving the mothers. since the literacy levels in mothers have gone up markedly in recent years, pamphlets with important messages in the local language telugu were distributed. even if the woman was illiterate, there was someone in the family who could read and explain. impact on acceptance of homestead gardens was done by keeping records of land diverted from traditional crops like paddy and sugarcane to vegetables and fruits, approximate quantum and variety grown and utilised-household consumption vs sale. families were specifically explained that the purpose of the project was household consumption of home-grown vegetables, particularly by women and children and not for sale. families were also encouraged to grow pulses and millets. improvement in understanding of food, nutrition, sanitation, child caring practices and health (some common infectious diseases-their cause and management) was assessed through initial and end-line knowledge, attitude and practice (kap) surveys of mothers with 6-24-monthold children using pretested questionnaires. initial survey was done by the project staff and final survey by a local woman with proper training, to avoid investigator bias. household consumption of different foods (weekly frequency, and per capita per day consumption) was assessed by questioning the mothers about food consumed in a typical week when there were no guests and no feasting or fasting [26] . in india, the integrated child development scheme (icds) facilitates preschool education, infant and child feeding and maintenance of records of birth weight and growth of preschool children. all villages above a population of 1000 have one or more icds centres called anganwadis, managed by a trained anganwadi workers. in the last two studies, birth weight and monthly growth records of children under 2 years of age were examined to assess the impact on nutrition. initially less than 30% of the targeted households grew vegetables or fruits. at the end of the study, 90% of the households had diverted small bits of land (less than half acre) to growing of vegetables and fruits, despite small and marginal holdings. table 1 gives data on crops grown, in the last quoted study as reported by the mothers in the kap survey. a marked increase in the number of households growing vegetables, pulses, maize and millets and a small reduction in households growing rice was reported. some of these changes in cropping patter may be seasonal effects since the initial survey was done in the month of september and final survey in summer-april-may. comparison of initial and end-line kap surveys showed remarkable improvement in mothers' knowledge (and hopefully practice) of balanced diet, nutrients in foods, causes and signs and symptoms of nutritional deficiencies, food taboos during pregnancy (avoid foods like papaya and banana), infant feeding practice (initiation of breast feeding, and feeding colostrum, age of introduction of complementary feeding), washing hands with soap and water (not just water), right cooking practices (washing vegetables before cutting, not discarding excess water after cooking rice-a common practice) and causes of common infectious diseases like diarrhoea, malaria, tuberculosis, jaundice and their management ( [26, 27] and proceedings of ivth agricultural science congress, new delhi, india-under publication). in the first two studies, there was significant increase in the frequency [26, 27] as well as daily per capita consumption [26] of glv. similar significant improvement in the consumption of other vegetables was not seen. the homegrown vegetables replaced what was purchased from the market. however, in the first study where control nonintervention households from the same village were included for comparison [26] , there was a marked decline in the consumption of vegetables in the control households over time due to sharp increase in market price of vegetables. this suggests that homestead production at least shields against escalating market price. monthly inquiries showed that about 25-50% of home-grown vegetables other than glv were sold in the first study. 'for poor households, economic compulsions outweigh nutritional wisdom' [26] . this trend decreased in the subsequent studies by reiterating the purpose of the study. in the last mentioned study, remarkable improvement in the consumption of glv as well as other vegetables was observed (proceedings of ivth agricultural science congress, new delhi, india-under publication) ( table 2 ). very little was sold. the results of that study suggest that with sufficient advocacy, education and training, daily requirement of vegetables, particularly glv can be met from homestead gardens despite small and marginal holdings. some incentive like free distribution of seeds and saplings would help. this, however, will not ensure micronutrient security, unless the intake of pulses and animal products also goes up. in that study, some increase in milk consumption was also observed. this may be due to the government scheme of distributing buffaloes at highly subsidised rate. impact on birth weight and growth of children aged 6-24 months was assessed through the records maintained by the icds centres. in recent years, almost all deliveries are institutional. the aw worker maintains records of birth weight and monthly growth. scrutiny of these records over the study period was done in the second and third studies ( [27] , under publication). no effect on mean birth weight was observed. the incidence of lbw was less than 10% compared to the national average of about 20%. the incidence of moderate and severe malnutrition (weight/age) showed marked decline from over 30% to about 20%. in both the studies, seasonal variation was seen with increase in undernutrition percentage during monsoon. this is a known phenomenon due to greater morbidity during monsoons. egg is one of the most wholesome foods. over the years the consumption of meat has come down in india, but that of eggs has gone up due to marked increase in commercial poultry farms [29, 30] . commercial farms have largely benefitted urban areas. backyard poultry is an important option for rural areas, and widely adopted, with nondescript birds with low egg yields-30-40 eggs per year. these birds are well acclimatised, have prominent brooding behaviour and mothering ability. in recent years, improved breeds of byp, which can lay 150-200 eggs per year, have been developed [28] . unlike seeds and saplings, which were given free, poultry birds were sold after immunisation. families bought three birds and one was given free as incentive. proper night shelters had to be built to prevent predation. initially two improved breeds gramapriya developed by the project directorate, icar, hyderabad, and rajasri developed by aicp on poultry breeding, sri venakteshwara veterinary university, hyderabad, were introduced. more recently, older birds of rainbow rooster breed, purchased from indbro research and breeding farm, hyderabad, are being distributed. in all the projects, the frequency per week of egg consumption by the families initially was less than 2. per capita per week consumption was also less than 2 eggs. subsequent to the introduction of the byp with high eggyielding birds there was significant improvement. thus in the two projects, the weekly frequency of egg consumption increased by 73% and 139%, respectively. per capita number of eggs consumed per week increased by 347% and 143%, respectively, [26] [27] [28] . to facilitate wider dissemination of the model of nutritionally sensitive and environmentally sustainable farming, and backyard poultry (with high egg-yielding birds), along with bcc in the area of, food, nutrition, sanitation and health developed in the earlier projects, dct has set up a rural hub. this project was initiated in september 2018, with financial support from tata, lock heed martin aero structures ltd., hyderabad, under their corporate social responsibility-csr for a period of 1 year. it was further continued with financial support of dangoria charitable trust. the design is to target five villages with a total population of eight to ten thousand, over a period of 6 months. after a month of planning and initial kap survey of mothers with children under 3 years of age, on aspects of food, nutrition, sanitation and health (as described earlier), four centralised training programmes on topics such as maternal and child health and nutrition; nutrition gardens; backyard poultry and food processing are conducted each month for 4 months. decentralised hands on training are also given. an end-line kap survey is conducted in the sixth month. like in the earlier projects, pregnant women and mothers with children under 3 years of age are the main target. for sustainability the anganwadi workers and accredited social health activists from the villages are involved in the training. planting material for raising gardens is given free to families with a pregnant woman and children under 3 years. high egg-yielding poultry are given to all interested families. families buy at least four to five birds. hitherto two sets of five villages have been covered. impact is assessed from the number of families that have started growing vegetables, acceptance of byp and improvement in mothers' knowledge of food, nutrition, child feeding practices, health etc. as judged from initial and end-line kap, surveys as described in the earlier longer duration studies. all the families (except three families in the initial survey) had own land. the three families also had leased land. but the holdings were marginal-3-5 acres. farming and farm labour (working on each other's' farms) was the main occupation. all the women were literate and 80% had studied beyond fifth standard. some women had studied up to intermediate. table 3 (second set of five villages) show significant increase in the percentage of households growing vegetables at the end of 6 months. some increase in the number of households having byp was also seen. there was remarkable improvement in the mothers' knowledge of food consumption during pregnancy, reduction in pregnancy associated food taboos, infant and child feeding practices, healthy cooking practices and components of a balanced diet. improvement in knowledge of-nutrients in foods, functions of different nutrients was weak though majority did mention foods rich in vitamin a in the end-line survey. understanding of the cause and management of diseases like diarrhoea (contaminated food and water), malaria (mosquito bite), tuberculosis (through cough) and jaundice (contaminated food and water) showed significant increase. over the years, there has been remarkable increase in women's literacy, antenatal check-ups, institutional deliveries (home deliveries are very rare) and immunisation coverage, in the villages of medak district where the authors work. the path from agriculture to nutrition is generally assumed to go via agriculture income. important as income is; income alone cannot ensure dietary diversification unless the community is educated about the importance a balanced diet, and nutrition, for health and productivity. emphasis of agriculture is generally on providing calories to quench hunger and at best proteins. this tends to be achieved through cereals and some legumes. hidden hunger remains hidden from the vision of not only people but also planners and policy makers. nutritionally sensitive and environmentally sustainable agriculture is a more holistic approach, in a country like india where agriculture is the main occupation of more than 60% of the households. generally farmers are reluctant to deviate from traditional cropping pattern. yet the studies of the authors and others discussed in this paper show that even small and marginal farmers can be persuaded to diversify into raising homestead gardens of micronutrientdense vegetables and fruits by combining social engineering with technological engineering. some incentive like giving free planting martial helps. since most poor rural women work in fields or go for labour work, they were given money for travel and lunch was served, when they came for the centralised meetings to compensate for the lost wage for the day. as mentioned earlier, homestead gardens may be able to supply vegetables to meet the household requirement, but that alone will not be sufficient to meet the requirement of micronutrients. inclusion of pulses, millets and animal husbandry along with horticulture should be attempted. the authors did advise about growing pulses and millets, and gave seeds of finger millet and iron fortified pearl millet to interested households. small but significant improvement in consumption of millets was seen ( table 2 ). pulse consumption did not show any increase. introduction of poultry did help in increasing egg consumption. in the long duration projects (3 years), many families set up vermicompost beds. incentive by way of earth worms was given. only few families used botanical pesticides. the remarkable improvement in the mothers' knowledge of food, nutrition, infant and child feeding practices, sanitation and common communicable diseases, with education, is very gratifying since an informed mother is an empowered mother, and can make a lot of difference to the family's diet, nutrition and health. involving the local health functionaries also helps sustainability. all community-based technological interventions should have robust educational component so that the community understands the importance of the technological intervention. nutrition gardens have recently caught the imagination and attention of many state governments and ngos in india. suri has summarised some of these unpublished initiatives [31] . this movement needs to gain momentum with a robust information, education and training strategy. the current swatch bharat clean india programme in india will hopefully complement this effort in reducing malnutrition. homestead production of diverse foods to ensure dietary 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poverty in india: looking beyond the farm gate new delhi: ministry of agriculture nutrition gardens: a sustainable model for food security and diversity. orf issue brief no. 369. observer research foundation optimal nutritional status for a well-functioning immune system is an important factor to fight against viral infections the role of nutrition in the immune system: should we pay more attention acknowledgements the technical support for the studies conducted by the dangoria charitable trust was provided by n. venkatesh (agriculture and horticulture), p. pentiah (poultry) and k. v. lakshmi conflict of interest the authors declare that they have no conflict of interest. also, the little bit of unpublished recent research reported is original.publisher's note springer nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. key: cord-322866-au76nnzg authors: bleizgys, andrius title: vitamin d and covid‐19: it is time to act date: 2020-10-27 journal: int j clin pract doi: 10.1111/ijcp.13748 sha: doc_id: 322866 cord_uid: au76nnzg vitamin d (vitd) deficiency is considered a global problem and might be associated with increased susceptibility to covid‐19 illness. in the light of covid‐19 pandemic, vitd might be a promising agent for fighting the sars‐cov‐2, since vitd is involved in various pathophysiological mechanisms that occur during covid‐19 infection. high‐dose vitd supplementation, particularly for risk groups, could be recommended to achieve and maintain optimal (range 40‐60 ng/ml) serum 25‐hydroxy vitamin d levels (marker of vitd status) both for covid‐19 prevention and treatment. face mask and covering a cough with an elbow, introducing social distancing measures, 'stay at home' guidelines, traveling restrictions and closing state borders, expansive testing and contact tracing. 3 there is a need to find additional agents that could be effective and acceptable for fighting the covid-19 pandemic, especially keeping in mind the possible 'second wave' of covid-19 expected to be in the next autumn or winter. from the beginning of 2020, there is accumulating evidence that vitd is a potential candidate for this purpose. for humans, the main source of vitd is its synthesis in the skin under the influence of solar ultraviolet radiation. after two hydroxylation steps, vitd is transformed into an active form 1,25-dihydroxyvitamin d, or calcitriol. the first step takes place in the liver and 25-hydroxyvitamin d (25oh-d) is produced. the second hydroxylation is performed by renal proximal tubular epithelial cells as well as by some extra-renal tissues and cells, such as endothelium and macrophages. the major circulating form of vitd is 25oh-d and it is currently accepted as the best marker of vitd status. calcitriol produces its effects via the vitd receptors that are found almost on all cell types of the human organism, and thus is capable of suppressing or stimulating the expression of numerous genes. 6 vitd appears to be essential not only for 'healthy bones' but also for many other organs and tissues. 7 however, low vitd status seems to be a global problem: it was estimated that about 1 billon humans could have vitd deficiency or insufficiency. 8 a high prevalence of low vitd was found in many european countries as well, particularly in eastern and central europe. [9] [10] [11] much better vitd statuses were found to be in countries such as norway and sweden, 12 the latter findings might be explained by high consumption of oily fish, cod liver oil, fortified food and/or higher rates of vitd supplementation. 13 there is increasing evidence that vitd deficiency may have been underestimated/ignored in low latitudes, even in tropical countries. 14 more recent data showed that, in european countries, in particular southern, eastern and western europe prevalence of vitd deficiency (if defined as serum 25oh-d levels <20 ng/ml) could be 30%-60%, and up to 80%-in the middle east. 13 many factors can contribute to high prevalence of low vitd, eg, modern sedentary life style (less and less time outside in the sunlight), obesity and air pollution (particularly, in large cities) that reduces the amount of solar uv radiation reaching the humans, dietary habits (decreased consumption of diary and sea fish), avoidance of sunlight even during leisure time, use of sunscreen (fear of skin cancer), cultural habits (eg, clothing style) in some populations, as well as low rates of vitd supplementation and absence of food fortification with vitd programs in many countries. [15] [16] [17] all these reasons are also important risk factors for vitd deficiency for those living in 'sunny' southern european countries such as italy and spain, where avoidance of heat (and the sunlight, too) is also a common practice. besides that, one must consider a growing number of elderly people in those countries that are at extremely high risk of developing vitd deficiency. it is well known that older persons (aged >60 years) may tend to have low vitd because of many reasons: lessened mobility (as a result of chronic diseases), increased adiposity, reduced rates of synthesis of vitd in the skin (mainly, because of reduced amounts of 7-dehydrocholesterol-the precursor of vitamin d3-in the skin), reduced appetite, poorer nutrition and reduced vitamin d absorption in the gut. in addition, pharmaceutical drug use typically increases with age, and some medications (eg certain anti-epileptics, antifungals, antihypertensives, antineoplastics, antibiotics and anti-inflammatory agents) are known to impair vitd metabolism and to decrease serum 25oh-d levels. 4, 18, 19 already in february 2020 it was proposed that vitd deficiency might increase covid-19 risk, since low vitd was shown to be prevalent in many people (including otherwise 'healthy' ones), mostly at the end of winter season, particularly, in people who are housebound, or institutionalised; and covid-19 was firstly identified in winter 2019 and mostly affected middle-aged to elderly people. 20 it was also suggested that geographical location might influence the risk of mortality as a result of covid-19, since mortality was relatively low for many countries below 35 degrees latitude. 21 not surprisingly, higher sunlight intensity should increase vitd production in the skin and, consequently, improve vitd status and potentially health. however, high mortality rates were reported from 'sunny' italy, spain and france, ie, from countries where severe vitd deficiency is also prevalent. therefore, the location (the latitude) of the country or the city seems not to be the main factor determining vitd status as well as covid-19 mortality rates. 21 indeed, multiple confounders, age in particular, may interfere with any potential relationship between vitd and covid-19, since age of population is an important determinant of severe covid-19 outcomes. 22, 23 it was also hypothesised in march 2020 that low vitd could be the link between age, comorbidities and increased susceptibility to complications and mortality as a result of covid-19 infection in some regions, eg northern italy. 24 indeed, the covid-19 virus is found to be more dangerous for elderly people, especially for those who have comorbidities, in particular, arterial hypertension, obesity, diabetes, cardiovascular or cerebrovascular diseases, as well as for ethnic minority populations with darker skin, since these patients have higher risk of severe covid-19 and also higher mortality rates. 1, 14, 17, 25 interestingly, these mentioned covid-19 risk groups could also be considered as risk groups for vitd deficiency. 17, 19, 26 epidemiological studies of the past showed inverse relationships between vitd status and certain clinical events: lower 25oh-d levels are associated with higher risk of developing ards, heart failure and sepsis; the latter conditions are also known to increase risk for severe covid-19 and death from covid-19. 4, 27 in addition, higher mortality rates in men could be explained, at least in part, by the fact that elderly men have higher prevalence of vitd deficiency; however, the role of different levels of sex hormones and other factors also seem to be important. 28 in switzerland, a cohort study that analysed patients who underwent a nasopharyngeal swab pcr analysis for sars-cov-2 found that covid-19 positive cases had significantly lower median 25oh-d levels than covid-19-negative ones. 29 in contrast, analysis of uk biobank data 30 showed no association between 25oh-d and covid-19 infection (presence, regardless of severity) after adjusting for potential confounders; despite 25oh-d concentration being lower in black and minority ethnic participants, no evidence that it might play a role in their higher risk of covid-19 infection was found. but, as correctly stressed by the latter study authors, they used baseline measurements including 25oh-d levels and health status that have been obtained a decade ago (between 2006 and 2010), and 'it would be preferable to have measurements immediately preceding development of covid-19'. 30 some authors propose that vitd status could also strongly account for variability in covid-19 severity. 31 this suggestion might be supported by the data from european countries: there exists a negative correlation between levels of mean 25oh-d and number of cases of covid-19 for 1 million (1 m) of population in each country, as well as a negative correlation between levels of mean 25oh-d and the number of deaths caused by covid-19/1 m. 23 similar findings regarding mean 25oh-d levels and covid-19 mortality rates were found by others in the study on data from 12 european countries. 17 however, a retrospective study on data from 20 european countries showed a significant negative correlation for levels of mean vitamin d with covid-19 cases, but not with death rates per 1 m of population. 32 but in a recent meta-analysis with a total of 1,368 covid-19-positive patients, low vitd levels (ie deficiency) were significantly associated with poorer patient outcomes (eg development of ards, intensive care unit admission or death) and prognosis. 33 of note, vitd could also provide protection against other infectious diseases. as stated in many reviews, studies showed that adequate vitd status is associated with lower risk of seasonal influenza and acute upper respiratory tract infections, dengue fever, rotavirus infection, viral hepatitis b, as well as infections caused by some other coronavirus species; some interventional studies (however, not all) showed that vitd supplementation could also reduce the risk of some aforementioned infectious diseases. 4, 19, 27, [34] [35] [36] taken together, all these facts undoubtedly suggest relationships between low vitd and covid-19. some authors even suggested that patients having vitd deficiency should be considered as high risk group for getting severe illness from covid-19. 37 in addition, more and more humans haverisk of being less exposed to sunlight because of 'stay at home' mitigation strategies, 3, 17 consequently, many of us could be named as members of risk group for vitd deficiency, and, paradoxically, could be at a higher risk of being ill with covid-19 or other infections. certainly, further observational studies are needed; some guidelines for research in this field have also been recently suggested. 31,37 vitd, in its active form (calcitriol), has a pluripotent activity on the human organism. some of them, in the light of covid-19, need to be discussed. vitd helps to maintain firm intercellular junctions, eg tight junctions, gap junctions and adherent junctions. it is known that some viruses can disturb junction integrity, increasing infection by the virus and other microorganisms. 4 strong physical barriers through effective cell junctions are the body's first line of defense against pathogens. 19 in addition, the maintenance of tight junctions is necessary to prevent the infiltration of immune cells in lungs and other respiratory tissues 38 ; therefore, this might be important for the prevention of developing severe pneumonia and ards in covid-19. in conjunction with toll-like receptors, these substances have antimicrobial activity, eg killing bacterial cells and reducing viral replication. 4, 19 for instance, cathelicidin has direct antiviral activity against enveloped viruses such as hepatitis b virus, influenza, respiratory syncytial virus and possibly the sars-cov-2 as well. 14 a cationic peptide ll-37, derived from cleavage of the cathelicidin peptide, binds to target microbes, creating a pore in vulnerable bacteria or destroying the envelope of envelope viruses such as those of the corona virus family. 39 ll-37 is the only identified member of the cathelicidin family in humans that is expressed by respiratory epithelial cells. 40 it was demonstrated that during viral infection, calcitriol can be produced in the alveolar epithelial cells, and expression of cathelicidin gene increases. 41 human beta-defensin 2 can serve as a chemoattractant for other inflammatory cells involved in the defense system against pathogens. 19 vitd suppresses responses mediated by the t helper cell type 1 (th1), by primarily repressing production of inflammatory cytokines il-2 and interferon gamma (infγ); also, promotes cytokine production by the t helper type 2 (th2) cells, which helps enhance the indirect suppression of th1 cells by complementing this with actions mediated by a multitude of cell types; and also promotes induction of the t regulatory cells, thereby inhibiting inflammatory processes. 4 cytokine storm (cs) can be triggered by infectious diseases, rheumatic diseases and tumour immunotherapy, and it generally presents as systemic inflammation and multiple organ failure. 5 it is well known that cs is one of the main mechanisms that can severely damage the lungs and other organs in patients suffering from severe covid-19. cs is characterised by uncontrolled release of various pro-inflammatory cytokines and chemokines, eg interleukin (il)-1 beta, il-6, il-1ra, tnf (tumour necrosis factor)-alpha, il-17, monocytes chemoattractant protein-1, and many others, followed by increased serum ferritin levels, decreased natural killer (nk) cell count and alleviated nk function. all this results in damage of healthy cells, vascular leakage, severe exfoliation of alveolar epithelial cells, alveolar septal widening and damage, oedema and inflammatory cell infiltration, ultimately leading to lung dysfunction and hypoxia, as well as to hypercoagulability, thrombosis and multiple organ damage. 2, 3, 38 vitd is thought to be beneficial for prevention and/or treatment of cs, via the ability to decrease synthesis and secretion of various pro-inflammatory cytokines and to increase synthesis of some anti-inflammatory cytokines. 4, 5, 13, 19, 38 of note, regulation of inflammation is of particular importance in older adults, in the obese and those with chronic conditions as they have constant low-grade chronic (systemic) inflammation and may already be pre-set for a higher inflammatory response if exposed to covid-19. in other words, the aforementioned ones, in comparison to younger and otherwise healthier persons, are less capable of 'shutting-down' their inflammatory and immune response at the right moment, when that response becomes more dangerous than protective. a heightened immune response in people who are vitd deficient may therefore increase the potential for cs and consequent ards. 17, 42, 43 it is well known that reactive oxygen species (ros) production is augmented in various inflammatory diseases, and increased release of ros may also contribute to the damage of many organs and tissues. therefore, by decreasing the intensiveness of inflammation, as mentioned above, vitd might also help to fight the oxidative stress. in addition, it was shown that vitd might act directly on the production of ros, eg in mitochondria and endoplasmic reticulum. 44, 45 vitd also increases the gene expression of antioxidative enzymes, eg glutathione reductase and glutamate-cysteine ligase modifier subunit, and this was shown to help maintain higher levels of vitamin c, which is an antioxidant and has antimicrobial activity as well, and is suggested as a potential agent for fighting covid-19. 4 renin-angiotensin system (ras), also known as renin-angiotensinaldosterone system, is an important regulator of many actions in human organism, eg the vascular tone, diuresis and blood pressure. however, during some diseases, the overactivity of ras results in increase of angiotensin ii production and may lead to undesirable effects, such as prolonged vasoconstriction, arterial hypertension, augmented production of pro-inflammatory cytokines, thrombosis, fibrosis (eg in lungs), insulin resistance and liver dysfunction. 38, 46 some sars-cov-2-related covid-19 symptoms and pathological processes such as pulmonary hypertension, coagulopathy, diarrhoea, anosmia, ageusia, dermatitis, autoimmune inflammation of the central nervous system, and damages to various organs such as the lung, heart, kidney and testicle, are likely linked to an overreaction of ras in sars-cov-2-infected persons. 28, 46 vitd could reduce the synthesis of renin in the kidneys, and vitd hypovitaminosis may contribute to increase of ras activity. 38, 46 as shown in animal models, vitd may be beneficial in treating ards-it decreases lung permeability by modulating ras activity (see the references in 47 ). vitd can also increase angiotensin-converting enzyme 2 receptor (ace2) expression in the lung tissue and this could ameliorate lung damage in case of some infections. 23 ace2 is a transmembrane enzyme that catalyses conversion of angiotensin ii into angiotensin 1-9 (ang 1-9), which is converted by ace into the angiotensin vasodilator peptide 1-7 (ang 1-7) that acts via the mas receptor; ang 1-7 has also hypotensive and diuretic effects. 5 sars-cov-2 uses ace2 of target cells (eg type-ii pneumocytes) for fixation and penetration into these cells: spike glycoprotein of the virus binds to ace2, and therefore, ace2 was named a functional receptor of sars-cov-2. 1, 14 the binding of covid-19 spike protein to ace2 has been shown to downregulate ace2 and to promote ace activity, forming more angiotensin ii; and, in turn, to decrease ang 1-7 production. this mechanism may be involved in the pathogenesis of pulmonary hypertension and insufficiency caused by sars-cov-2 infection. 28, 48 it might appear that increase in ace2 expression (eg, caused by vitd) could increase covid-19 infection risk, although there are also some data that vitd could decrease ace2 expression. 3, 19 interestingly, angiotensin-converting enzyme inhibitors and angiotensin ii type i receptor blockers can also increase the expression of ace2, but there is no evidence that such effect is indeed harmful (eg increasing mortality from covid-19). 5 many authorities conclude that vitd, by decreasing ras activity and (probably) increasing the expression of ace2, overall has beneficial effects in case of covid-19 infection. 28, 38, [48] [49] [50] in severe covid-19 cases, there is a high risk of coagulopathies, in particular, risk of thrombosis, including microvascular thrombosis in the lungs. 51 vitd hypovitaminosis is tightly associated with increased risk of thrombosis. 52, 53 it was demonstrated that vitd or its analogs could decrease the expression of tissue factor, as well as pro-thrombotic plasminogen activator inhibitor-1 and thrombospondin-1, and upregulate the expression of thrombomodulin. 54, 55 therefore, it seems possible that restoring normal vitd status could help in reducing risk of thrombosis. in covid-19 disease, impaired functions of type-ii pneumocytes decrease the surfactant levels and increase surface tension. vitd can stimulate surfactant synthesis in alveolar type-ii cells, therefore, reducing surface tension 37 and improving lung function. vitd also helps in regeneration of endothelial lining and therefore may attenuate alveolar damage in case of ards. 1 importantly, vitd can downregulate the development of pulmonary fibrosis, which has been widely described as a common complication of ards. 56 in conclusion, there are many different pathways where vitd is involved, most of them being very promising and supporting the beneficial role of vitd. however, the processes described above were discussed separately just for simplicity. indeed, they are very complex and interconnected, and sometimes it might be very difficult to prove that a certain mechanism is dependent mostly on vitd itself rather than on the other agents used for treatment or prevention of infections such as covid-19. to be honest, one must point out that, to date, there is no clear evidence that vitd or its analogues could significantly impact the covid-19 incidence, severity or mortality. but some clinical trials (eg nct04334005) aiming to investigate these associations have already started, and that gives some hope that the exact role of vitd in preventing covid-19 and treating the patients will be elucidated. can also explain the lack of evidence from large-scale rcts regarding vitd role in prevention or treatment. nevertheless, vitd supplementation should be considered an adjuvant therapy for covid-19 patients and also whole population supplementation might be recommended. improvement in circulating 25oh-d levels opens possibilities for slowing disease progression or even improving survival of patients, and keeping in mind the good tolerability and safety of even high doses of vitamin d (for almost all patients), this approach complies primum non nocere principle. 37, 47 indeed, it was postulated that, in general, the risk of overdosing vitd tends to be next to zero, unless very large doses without physician supervision are being used for an extended period of time or mega-doses such as 1 million iu daily are taken for a few days. 19, 57 it was also speculated that vitd could be a cheaper alternative for expensive drugs suggested for treatment of covid-19 patients, eg tocilizumab, 31 or might have potency to be used together with drugs approved for covid-19 treatment, eg remdesivir. 58 it is reasonable to advocate for vitd supplementation more widely during covid-19 pandemic, as supplementing vitd in people who are already ill might be too late to be effective-in particular, in those patients who are presented to hospital in the hyperinflammatory stage of the disease. 59, 60 there is much controversy regarding overall 'normal' or 'optimal' serum 25oh-d levels. 61, 62 however, many scientists and clinicians prefer to use the cut-off value 30 ng/ml (75 nmol/l) as a lower bound of adequate vitd status, as it was suggested by the endocrine society, 63 and some also suggested, in the light of covid-19 pandemic, to achieve and maintain 30 ng/ml levels at least in elderly people 29 or in citizens of countries having high prevalence of vitd deficiency, particularly, in those patients with covid-19 who are at high risk of intensive care unit admission. 40 in contrast, others suggested 40-60 ng/ml as an optimal range for human health, since such levels might reduce the risk of some infections (influenza, other coronaviral etc), as well as the risk of certain types of cancer (eg colorectal), diabetes, rheumatic diseases and pregnancy complications. 4, 37, 57, 64 indeed, levels 40-60 ng/ml seem to be acceptable, since they are much lower than the 'toxic' 25oh-d levels considered to be at ≥100 ng/ml 26 or at ≥150 ng/ml. 40 in addition, one could speculate that many patients would not benefit from 30-<40 ng/ml 25oh-d levels if they are 'low-responders' to vitd. 64, 65 overall, it is clear that for a majority of patients the minimal target is to achieve and to maintain at least 30 ng/ml 25oh-d levels, but it is desirable to achieve and maintain 40-60 ng/ml. who should be measured for serum 25oh-d levels? some authorities proposed that all inpatient and outpatient populations with covid-19 should be tested, 37 while others suggested that serum 25oh-d levels had to be measured in every patient before starting the general covid-19 treatment 20 and all hospitalised patients upon arrival should be tested for vitd status. 66 with regard to population, it was suggested to test the groups of people who were likely to have low 25oh-d concentrations and could benefit from higher concentrations, such as pregnant women, the obese, people with chronic diseases and elderly people. 4, 67 testing of all hospital inpatients seems reasonable, at least from the practical point of view, since many other blood tests are performed for these patients during their stay at hospital. however, testing of outpatients for 25oh-d levels seems to be problematic in some way: covid-19 patients (usually having mild covid-19 illness or no symptoms) should keep strict rules of self-isolation, and covid-19-negative persons, during the covid-19 pandemic, should avoid visiting any clinic or laboratory, unless it is extremely needed, particularly if they belong to the covid-19 risk group (eg persons aged >60 years, or patients with certain chronic illnesses). what dose of vitd should be recommended? in general, some experts still suggest taking small vitd doses, eg the association of uk dietitians recently recommended 400 iu per day, 68 and researches from tilda study recommended minimal daily dose of 400 iu in general, and 600-800 iu daily dose for those who are housebound (as a result of illness or quarantine for an extended period), and 800-1000 iu daily dose for persons older than 70 years. 69 while the others are advised to take 800 iu to 2000 iu daily for all hospital inpatients, nursing home residents and elderly people, as well as for other vulnerable groups (eg those with obesity or overweight, those with diabetes, immunocompromised peoples, vegetarians, smokers, dark skinned or healthcare workers). 34 recent review stated that 2000 iu per day is enough to maintain strong immunity against respiratory infections. 70 usa experts suggested 800-4000 iu daily dose, since there is no clear evidence that higher than 4000 iu vitd doses are effective for covid-19 prevention or treatment. 71 in line with this, daily or weekly, daily equivalent doses of 1000-4000 iu were proposed recently, 72 and others also recommended not to exceed 4000 iu daily dose, keeping in mind also vitd from other sources than supplements (ie the skin and fortified food). 73 however, is it very questionable whether daily doses up to 2000 iu would be really sufficient for achieving the desirable 25oh-d levels of 40-60 ng/ml, particularly in low vitd risk groups, since, in fact, these doses should be considered only as prophylactic for non-risk group patients (in regard to vitd deficiency) in order to achieve and maintain 25oh-d levels at ≥30 ng/ml. 26 therefore, suggestions to take 2000-5000 iu or even higher doses in case of vitd deficiency seem more reasonable. 4, 19, 64 interestingly, it was demonstrated that a daily oral supplement of 4000 iu of vitd during 10 days represented an adequate dose to enhance dengue virus control and reduce the cytokine response, in vitro, suggesting that vitd can, in fact, restrict the viral assault. 74 grant et al 4 suggested, as alternative, for people at risk of influenza and/or covid-19 to consider taking 10 000 iu/d of vitamin d3 for a few weeks to rapidly raise 25oh-d levels up to 40-60 ng/ml, and after that 5000 iu/d to maintain these levels ('grant's schema'). however, they warned that, when such high doses of vitamin d are being taken, calcium supplementation should not be high to reduce risk of hypercalcaemia 4 ; in addition, they recommended supplementation with magnesium (daily dose in the range 250-500 mg/d), since magnesium acts as a cofactor in many enzymes involved in vitd metabolism. others suggested using vit d loading doses of 200 000-300 000 iu in 50 000 iu capsules to reduce the risk and severity of for covid-19 patients, in order to achieve 25oh-d levels above 40 ng/ml, ebadi et al 37 suggested 50 000 iu vitd twice a week in the first week (100 000 iu total), and to continue with the dose of 50 000 iu taken once a week for the second and third weeks. then, following doses of 50 000 iu is recommended along with monitoring of 25oh-d levels ('ebadi's schema'). in developing practical guidelines for vitd supplementation in adults during the covid-19 pandemic, several main aspects should be considered: 1. daily vitd dose up to 10 000 iu is considered generally safe for almost all patients. 4 only few patients are 'vitamin d hypersensitive', since they have or are at higher risk of develop hypercalcaemia even from small supplemental vitd doses, eg in case of primary hyperparathyroidism or granulomatous diseases such as sarcoidosis or active tuberculosis, 26, 63, 75 or in rare cases when catabolism of vitd metabolites is impaired because of mutation of specific genes (eg cyp24a1). 76 2. if recent 25oh-d measurement is not available, all those without prior supplementation could be considered as potential vitddeficient patients who might require high vitd doses to reach sufficient 25oh-d levels. some patients, eg obese persons, the elderly or patients having malabsorption syndrome (further in the text named vitd risk groups) might require much higher vitd doses. 26, 59, 63 3. if recent 25oh-d measurement is not available, those already taking supplements should increase their doses 1.5-2-fold, since the older target for their 25oh-d level is supposed to be at least 30 ng/ml, and not at least 40 ng/ml as it is suggested currently. if the recommended doses from previous guidelines 26, 63 are multiplied by 2, they will be closer to or within the recommended range of 5000-10 000 iu/d as discussed above. 4. if a patient is on supplementation and the vitd supplement is well tolerated, consider using the same supplement. 5. regarding dosing regime, taking supplements daily or once a week seems to be a better choice than taking mega-doses once in 1-3 months. 4, 19, 35 6. if currently 25oh-d measurement is not available and a large dose (either daily or weekly) is still prescribed, analysis of 25oh-d levels (preferably, serum calcium levels, too) should be performed in no longer than 1-1.5 month, for two reasons: (a) to evaluate the efficacy of supplementation (very important in case malabsorption is suspected), and (b) to detect vitd intoxication early enough. 26, 32, 63, 77 in summary, based on these assumptions, brief simplified recommendations may be drafted: 1. all inpatients suffering from covid-19 should be tested for 25oh-d levels at the admission day. if 25oh-d levels are below 40 ng/ml, vitd dosing according to 'grant's schema' or 'ebadi's schema' should be started as soon as possible. 2. outpatients with covid-19 and those without covid-19: • if baseline 25oh-d levels are unknown (measurement is not possible at the moment): • for those already on supplementation, increase the doses twofold (however, daily doses should be within range 4000-10 000 iu) for 1-1.5 month; then check 25oh-d levels; • for those without prior supplementation, suggest vitd dose 4000 iu/d (for those of vitd risk groups-consider 6000-8000 iu/d), or alternatively, 50 000 iu once a week; check 25oh-d levels in a 1-1.5 month. • if current 25oh-d levels were measured, strategy depends on the results: • levels 40-60 ng/ml: follow the current supplement dosing. levels >60-100 ng/ml: suspend vitd supplementation for 1 or 2 months, then check 25oh-d levels. levels >100 ng/ml: stop vitd supplementation, access calcaemia and calciuria, administer treatment in case of hypercalcaemia etc as described elsewhere. 26 vitamin d is almost undoubtedly linked to many viral infections, inthere is nothing to lose from that implementation, and potentially much to gain. 60 the author declares no conflict of interest. https://orcid.org/0000-0002-0285-6123 a comprehensive literature review on the clinical presentation, and management of the pandemic coronavirus disease 2019 (covid-19) rheumatologists' perspective on coronavirus disease 19 (covid-19) and potential therapeutic targets covid-19: the inflammation link and the role of nutrition in potential mitigation evidence that vitamin d supplementation could reduce risk of influenza and covid-19 infections and deaths mechanism of inflammatory response in associated 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minimize risks synergistic effect of vitamin d and remdesivir can fight covid-19 perspective: vitamin d deficiency and covid-19 severity -plausibly linked by latitude, ethnicity, impacts on cytokines, ace2 and thrombosis vitamin d for covid-19: a case to answer? the 2011 report on dietary reference intakes for calcium and vitamin d from the institute of medicine: what clinicians need to know vitamin d supplementation guidelines evaluation, treatment, and prevention of vitamin d deficiency: an endocrine society clinical practice guideline immunologic effects of vitamin d on human health and disease the concept of the personal vitamin d response index early nutritional supplementation in non-critically ill patients hospitalized for the 2019 novel coronavirus disease (covid-19): rationale and feasibility of a shared pragmatic protocol targeted 25-hydroxyvitamin d concentration measurements and vitamin d3 supplementation can have important patient and public health benefits the association of uk dietitians. covid-19/coronavirus -advice for the general public vitamin d deficiency in ireland -implications for covid-19. results from the irish longitudinal study on ageing (tilda) optimal nutritional status for a well-functioning immune system is an important factor to protect against viral infections myth busters: dietary supplements and covid-19 commentary: myths and facts on vitamin d amidst the covid-19 pandemic vitamin d and sars-cov-2 virus/covid-19 disease vitamin d supplementation: a potential approach for coronavirus/covid-19 therapeutics? requirements for vitamin d across the life span mutations in cyp24a1 and idiopathic infantile hypercalcemia practice implications for preventing population vulnerability related to vitamin d status how to cite this article: bleizgys a. vitamin d and covid-19: it is time to act key: cord-300192-fgueg4mo authors: richardson, david p.; lovegrove, julie a. title: nutritional status of micronutrients as a possible and modifiable risk factor for covid-19: a uk perspective date: 2020-08-20 journal: the british journal of nutrition doi: 10.1017/s000711452000330x sha: doc_id: 300192 cord_uid: fgueg4mo recent scientific evidence has indicated that the elderly have increased risk of covid-19 infections, with over 70s and 80s being hardest hit – especially residents of care homes and in clinical settings, ethnic minorities, people who work indoors and those who are overweight and obese. other potential risk factors include lack of exposure to sunlight, darker skin pigmentation, co-morbidities, poor diet, certain medications, disadvantaged social and economic status, and lifestyle factors such as smoking and excessive consumption of alcohol. a key question is to understand how and why certain groups of people are more susceptible to covid-19, whether they have weakened immune systems and what the roles of good nutrition and specific micronutrients are in supporting immune functions. a varied and balanced diet with an abundance of fruits and vegetables and the essential nutrients like vitamin d, vitamin a, b vitamins (folate, vitamin b(6) and vitamin b(12)), vitamin c and the minerals, fe, cu, se and zn are all known to contribute to the normal functions of the immune system. avoidance of deficiencies and identification of suboptimal intakes of these micronutrients in targeted groups of patients and in distinct and highly sensitive populations could help to strengthen the resilience of people to the covid-19 pandemic. it is important to highlight evidence-based public health messages, to prevent false and misleading claims about the benefits of foods and food supplements and to communicate clearly that the extent of knowledge between micronutrients and covid-19 infection is still being explored and that no diet will prevent or cure covid-19 infection. frequent handwashing and social distancing will be critical to reduce transmission. the risk of covid-19 infection and death increases significantly among older people (1) , especially those over 70 and 80 years, and those with co-morbidities such as obesity, cvd, hypertension and diabetes (2) . of particular interest is the disproportionate number of deaths in black, asian and ethnic minorities (3) . in the uk, two-thirds of healthcare workers who have died from covid-19 were from ethnic minorities, including doctors, dentists, nurses, midwives and healthcare support workers (3) . many of the risk factors identified so far that are related to viral infections and deaths from covid-19 have underlying associations with nutritional status and specific essential nutrients that are known to contribute to the normal functions of the immune system. important nutrients that support the immune function include vitamins a and d, the b vitamins (folate, vitamins b 6 and b 12 ) and vitamin c, and the minerals and trace elements zn, fe, se and cu (2, (4) (5) (6) . deficiencies and suboptimal nutritional status of these micronutrients can potentially decrease resistance to infections and reinfections. deficiencies of nutrients develop progressively over time, and several subclinical stages occur long before clinical symptoms of deficiency appear, including depletion of nutrient stores, biochemical adaptations and impairments of metabolic pathways and functions (7) . validated biomarkers for the micronutrients supporting the immune responses are available and can provide evidence about baseline nutritional status, dietary exposure, impact of nutritional interventions and genetic factors influencing micronutrient metabolism (8) (9) (10) (11) . gradually, the different lines of evidence from clinical, nutritional, epidemiological and mechanistic studies are helping to elucidate plausible and biologically relevant relationships between nutritional status and risk of covid19. this evidence can help develop advice for governments and health professionals concerning how best to target vulnerable groups of the population and to identify nutritional policy solutions. vulnerability of people who are deprived of sunlight and are obese vitamin d directly affects immune responses, and there are many potential mechanisms by which it may reduce the risks of viral and bacterial infections (12) (13) (14) (15) . the major source of vitamin d in humans can be via the action of uvb radiation in sunshine on skin, with estimates of cutaneous synthesis providing 80-100 % of the vitamin d requirement of the body with adequate sun exposure (14) . factors that prevent or impede year-round dermal synthesis include season, latitude and prevailing weather conditions, as well as skin pigmentation, age, sunscreen usage, working environment, outdoor activity and sun exposure behaviour. melanin in skin reduces penetration of uvb and thus contributes to lower vitamin d status in darkskinned individuals (14) . in the absence of sufficient exposure to sunlight, dietary sources of vitamin d, including conventional foods high in vitamin d, fortified foods and food supplements, are necessary to meet nutritional requirements and to avoid vitamin d deficiency. to ensure optimal vitamin d status, use of vitamin d supplements is often required, as sunlight exposure and dietary intake are usually insufficient in many individuals (15) . dermal synthesis of vitamin d may also be less efficient in older people than in younger adults (13, 14, 16) . people who wear clothes that cover most of their body or who are confined indoors, especially for extended periods of time, and residents in care and nursing homes are very likely to have low exposure to sunlight. in a systematic review of the scientific literature researchers discovered that a high percentage of indoor workers (91 %) had suboptimal vitamin d status, which was highest among shift workers (80 % of individuals) and healthcare students (72 %) (17) . sunlight deprivation accounted for a higher risk of both vitamin d insufficiency and deficiency, with healthcare workers among the most vulnerable groups. the authors concluded that job type may be a major factor in vitamin d deficiency and that guidelines on screening for vitamin d nutritional status and mitigation strategies, such as supplementation, should take into account different jobs and shift patterns. these people, together with those with low intakes of vitamin d in the diet, and those who are socially or economically disadvantaged, are particularly vulnerable to deficiencies and suboptimal nutritional status. furthermore, naturally rich sources of vitamin d in the diet are few and infrequently consumed. dietary supply of vitamin d is typically unable to offset the widespread deficiency of uvb-induced synthesis in the skin unless supplemental vitamin d is used (13, 18) . there is an association between obesity and low vitamin d status, and obesity and inflammatory conditions increase the risk of vitamin d deficiency (18) . in a very recent study, the high prevalence of vitamin d deficiency in people in countries in the northern hemisphere exposed to insufficient sunlight has been hypothesised to be linked to a possible role of vitamin d in suppressing the severe inflammatory responses seen in very ill covid-19 patients and in covid-19 deaths (19) . obesity is also associated with chronic inflammation in metabolic tissues, and vitamin d is a potent immunomodulator and anti-inflammatory agent. the constant state of low-grade inflammation, characteristic of obesity, may therefore increase requirements for vitamin d (20) . the fact that obesity is associated with lower blood 25-hydroxyvitamin d (25(oh)d) concentrations, a recognised biomarker used to assess the risk of vitamin d deficiency and suboptimal intakes (12) (13) (14) (15) , may be because the lipophilic pool that forms the reservoir of vitamin d in the body is much greater in obese subjects. such individuals typically need longer exposure to uvb radiation or higher amounts of vitamin d supplementation than those of ideal bmi (21) . undernutrition and malnutrition in the community and residents of care and nursing homes across the uk, thousands of care homes are experiencing covid-19 infections and deaths among their residents, many of whom are suffering from dementia. these elderly residents of care homes are acutely vulnerable to covid-19 (4) . undernutrition and malnutrition have been reported over many decades among people in care and nursing homes and in hospital patients (22) (23) (24) (25) . a significant proportion of hospitalised patients show evidence of impaired nutritional status on admission to hospital including low blood 25(oh)d concentrations and low levels of vitamins b 1 , b 2 , b 6 , folate and vitamin c (24) . patient outcomes are quite likely to be affected by increased medical complications impacting on length of stay and convalescence, severity of the disease, decreased survival rates and ability to live at home (24) . common nutritional problems in the community and in care homes are low energy intakes, weight loss and vitamin and mineral deficiencies (26, 27) due to loss of appetite and age-related loss of senses of taste and smell for reasons including illness, infections and some medications (28) . sarcopenia, depression, co-morbidities such as obesity, changing body composition with increased adiposity and loss of lean body mass, hypertension, diseases of the intestinal tract (resulting in impaired absorption of nutrients), lack of intrinsic factor for absorption of vitamin b 12 , respiratory diseases and cognitive impairments are also common (24, 25) . vitamin d deficiency-related co-morbidities also include liver and kidney diseases, and organ transplant recipients are particularly vulnerable (29, 30) . psychological and emotional stress such as loneliness, loss of loved ones, anxiety and depression can all have negative effects on physical and mental health and well-being. medications such as antibiotics, anti-hypertensive, anti-inflammatory, anti-seizure and endocrine drugs are contraindicated for vitamin d and can lead to lower blood 25(oh)d concentrations and interfere with vitamin d functions in the body (31) . the metabolism and actions of vitamin d are well known in relation to bone health, but increasing evidence is emerging about its role in respiratory health, including potential impact on inhibiting pulmonary inflammatory responses and enhancing innate defence mechanisms against respiratory pathogens (2, 5) . circulating blood 25(oh)d concentrations have been associated with normal lung function, and there is an increasing evidencebased scientific rationale for the immunomodulant, antiinflammatory and anti-infective actions of vitamin d (15) . for example, in a systematic review and meta-analysis, vitamin d was shown to protect against acute respiratory tract infections (arti), and patients who were severely vitamin d deficient experienced the most benefit (32) . it has also been shown that there is a linear association between vitamin d status and respiratory infections and lung function (33) . the uk scientific advisory committee on nutrition has recently undertaken a rapid review of vitamin d and arti (34) . this review noted that currently, the interpretation of the evidence on vitamin d and arti was complicated because of differences in vitamin d therapeutic doses and regimens, study settings, participants, study duration, definitions and verification of outcomes (including type of respiratory infection). since 2017, evidence has suggested that, overall, there is no effect of vitamin d supplementation on reducing arti risk, and scientific advisory committee on nutrition concluded that the evidence at this time does not support recommending vitamin d supplementation to prevent arti in the general population. nevertheless, scientific advisory committee on nutrition will keep this topic under urgent review if emerging evidence on vitamin d and arti risk suggests a change to existing conclusions is warranted (34) . in a review of epidemiological evidence, cardiovascular risks and events have been associated with low vitamin d concentrations (35) . vitamin d is associated with cardiovascular benefits and the regulation of blood pressure with some evidence of its effect on reducing vascular stiffness and vascular dysfunction, although the data are inconsistent (18) . higher vitamin d status has also been associated with a lower risk of type 1 and type 2 diabetes (18) . the risk of heart failure has also been reported to be 12-fold higher in elderly people who are vitamin d deficient. this association shows a higher risk than obesity or heart arrythmia (36) . lifestyle factors, such as regular smoking, people living in population-dense urban areas or overcrowded living conditions and in regions impacted by air pollution, people unable to go outside into the sunshine, people who are malnourished, overweight or obese (37) or who drink excessive amounts of alcohol and those with low baseline blood 25(oh)d concentrations, or combinations of all these potentially confounding factors, are likely to have weakened immune systems and functions and be at increased risk of viral infections (2, 4, 5, 38) . the benefits of an active outdoor lifestyle and a varied and healthy balanced diet cannot be overemphasised. the uk national diet and nutrition surveys of nutrient intake and nutritional status published in 2019 (39) have shown a sustained worsening of the dietary intakes and chronic shortages of several of the nutrients involved in supporting the normal immune functions, including vitamin d, vitamin b 12 , zn, se, cu and vitamins a and c. low intakes of these essential nutrients over a 9-year period are evident in the general population of all age/sex groups. for example, an analysis of uk biobank data (40) found that vitamin d intakes from the diet of bangladeshi, indian and pakistani individuals ranged from 1·0 to 3·0 μg/dwell below the public health england and scientific advisory committee on nutrition recommendations for 10 μg/d (16) and the european food safety authority adequate intake of 15 μg/d (41) . vitamin d supplementation was low amongst uk south asians, with only 22 % of bangladeshis, 32 % of indians and 25 % of pakistanis taking a vitamin d supplement. within this group of south asians, women (39 %) were more likely to take a supplement than men (23 %) (40) . interestingly, an analysis of the uk biobank cohort showed a very high prevalence of low levels of blood 25(oh)d and vitamin d deficiency in uk/south asian adults (37) . however, in a recent study, the uk biobank data provided no evidence that plasma 25(oh)d concentrations explained susceptibility to covid-19 infection, either overall or observed differences between ethnic groups (42) . this conclusion has been subsequently challenged (43) , and further clinical and epidemiological studies are required to unravel the conflicting results. the national diet and nutrition surveys findings in 2018 of the micronutrient intakes for adults aged 65-70 years and 75 years and over showed that for vitamin d, mean intakes were 35 % of the reference nutrient intake for adults aged 65-74 years and 28 % reference nutrient intake for those over 75 years. inclusion of intakes from vitamin d food supplements brought the mean intakes up to 60 and 53 % for those age groups, respectively (44) . vegetarian and vegan diets (45) can also generally be low in nutrients such as vitamin b 12 , zn, cu, fe and se as well as vitamin d and the n-3 long-chain fatty acids dha and epa found mainly in oily fish and cod liver oil. in fact, the high prevalence of vegetarianism and the avoidance of all foods of animal origin in indian and ethnic minorities could exacerbate deficiencies and suboptimal intakes of all these essential nutrients. for example, zn bioavailability is influenced by high-fibre diets and their phytate content because of the binding of zn by these components in plant-based foods, particularly grains and legumes. dietary phytate is known to be a contributory factor for zn deficiency (46, 47) . in a study of seven western countries of intakes and deficiencies of eight trace elements in older adults (≥60 years) (27) , se deficiency was observed in 49 % of women and 37 % of men living in the community and 44 % of women and 27 % of men in care homes, nursing homes and retirement homes. zn deficiency was also observed in 31 % of community-based women and 49 % of men. significant proportions of both older populations showed insufficiencies not only of zn and se but also for fe, iodine and cu (27) . for se, the 2018 national diet and nutrition survey (44) showed that a substantial proportion of older adults in all age/sex groups had intakes below the lower nutrient reference intake, that is high risk of deficiency. of those aged 75 years or older, 34 % of men and 57 % of women had intakes below the lower nutrient reference intake. of women aged 75 years and over, 12 % had intakes below the lower nutrient reference intake for fe and zn compared with 8 and 3 %, respectively, in women aged 65-74 years. nutrients contributing to the normal functions of the immune system several essential nutrients contribute to the normal functions of the immune system. zn has a role in antiviral immunity (48) , and deficiency of dietary zn has been reported to increase susceptibility to infectious diseases. zn has also been given as an effective adjunct treatment in reducing mortality from severe pneumonia (49) . the risk of viral infections and several chronic diseases is modified by low se intakes and nutritional status (50, 51) . selenoproteins such as glutathione peroxidase play a crucial role in the body's response to oxidative stress (50, 51) . during viral infection, the pathogens induce oxidative stress by generating reactive oxygen species in host cells, which, if not counterbalanced by antioxidant defence mechanisms, leads to oxidative stress and the emergence of more virulent strains (48, 52) . the se content of plant and animal products can vary 10-fold according to soil and geographic origin, and the lowest se status is found in populations that eat vegetarian diets including plants grown in low-se areas of the world (53) . potentially relevant to the recent appearance of covid-19 in china is the association between lower regional se nutritional status and more severe reported outcomes of covid-19 cases in different regions of china (53) , although that does not prove cause and effect. multiple cellular and viral mechanisms involving se and selenoproteins could influence viral pathogenicity, severity and duration of respiratory symptoms, recovery and death rates from covid-19 (52) . cu-related enzyme cytochrome c oxidase is needed for energy production of immune cells and another cupro-enzyme, superoxide dismutase, plays a role in the protection of immune cells against reactive oxygen species. moderate or even marginal cu deficiency affects some activities of t lymphocytes and phagocytic cells adversely (54, 55) . although evidence for impaired function of the immune system resultant from fe deficiency in humans is scarce, changes have been demonstrated in in vitro tests and animal models. these mechanistic observations resulted in european food safety authority concluding that a cause and effect association has been established between dietary status of fe and a normal immune function (56) . in addition to the functions of vitamin d, vitamin a has crucial immunomodulatory roles, and vitamin a metabolites exert direct effects on immune functions (47, 57) . vitamin a deficiency is associated with impaired intestinal immune responses and increased risk of infectious morbidity and mortality in relation to gastrointestinal and respiratory infections. preformed vitamin a (retinol) is only found in animal-derived foods. carotenoid precursors of vitamin a, such as β-carotene, are abundant in green leafy vegetables and certain fruits, but intakes of fruits and vegetables in the uk are still well below the recommended number of five-aday servings. the national diet and nutrition surveys 2019 states that the proportion of people meeting the five-a-day target remains low, at about 30 % for adults and about 10 % for 11to 18-year-olds (39) . there is no evidence of direct immune impairments in vitamin e-deficient individuals and a restoration of a depressed immune system by the vitamin (58) , although vitamin e has important immunomodulatory effects and may confer protection against infectious diseases (59) . for example, clinical outcomes demonstrate a role for vitamin e in reducing the risk of respiratory tract infections by improving immune response in elderly nursing home residents (60, 61) . vitamin c contributes to normal immune functions and the inhibition of inflammatory processes (62) . vitamin c deficiency results in impaired immunity and higher susceptibility to infections. in turn, infections significantly impact on vitamin c levels due to enhanced inflammation and increased metabolic requirements (62) . vitamin c appears to exert a number of beneficial effects on cellular functions of both the innate and adaptive immune systems (62) . in addition, it has a very effective antioxidant role per se, but it is also needed for the regeneration of vitamin e (62) . there are numerous factors that can affect vitamin c status, including dietary intake, obesity, severe infections, institutionalisation and smoking (63) . smokers with low intakes of vitamin c show increased oxidative stress, and plasma vitamin c is decreased by about 40 % in male smokers (62) . vitamin c status, as measured by plasma and leucocyte concentrations, is lower in elderly people with chronic illnesses, especially in care and medical settings, compared with young adults (62) . other important water-soluble vitamins that contribute to the normal immune functions are the b vitamins folate, b 6 and b 12 (64) (65) (66) . vitamin b 6 is required as a coenzyme in the metabolism of antibodies and cytokines. lymphocytes isolated from vitamin b 6 -deficient people display reduced proliferation, reduced il-2 production in response to mitogens and reduced antibody production in response to immunisation (65, 67) . folate plays a crucial role in nucleotide synthesis and thus may affect immune cell proliferation and responsiveness. folate deficiency has been shown to reduce proliferation of various cell types and to reduce the proportion of circulating t lymphocytes and their proliferation in response to mitogen activation. in vitro studies demonstrated that all the effects on the immune system were reversible either by folate addition or nucleotide repletion (64, 68) . vitamin b 12 , along with vitamin b 6 and folate, is involved in the immune functions through their involvement in nucleic acid and protein biosynthesis. decreased availability of vitamin b 12 for rapidly proliferating b lymphocytes is believed to result in an impaired antibody response to pneumococcal polysaccharide vaccine and synthesis of specific ig (66, 67) . based on scientific assessments carried out by european food safety authority, the european register of authorised nutrient function health claims 1(69) include the specific nutrients vitamin a (including β-carotene), vitamin d, the b vitamins (folate, vitamins b 6 , b 12 ), vitamin c and the essential minerals and trace elements fe, cu, zn and se for their contributions to the normal functioning of the immune system (69) . however, to date, there have been no direct associations between status of these micronutrients and covid-19 infection. strategies to avoid nutritional deficiencies and ensure adequacy of micronutrient status in different populations the primary public health and nutrition strategy is to provide advice on the importance of a varied and balanced diet and a healthy lifestyle. however, when there is evidence of noncompliance with this advice, and where diet and nutrition surveys demonstrate inadequate micronutrient intakes and prevalence of low nutritional status, national nutrition strategies also include the addition of micronutrients to commonly eaten foods such as vitamin d added to margarines and fat spreads (food fortification) and the use of food supplements (13, 70) . overall, micronutrient status, particularly vitamin d status, may be exacerbated during this covid-19 pandemic as a result of the restrictions on movements, which may impair normal immune functions (2, (4) (5) (6) 71) . very recently, studies have shown that vitamin d plays a role in regulating and suppressing the cytokine inflammatory response that causes the acute respiratory distress syndrome observed in severe and often lethal forms of covid-19 (71) . in addition, a significant correlation has been shown between low serum vitamin d levels and mortality from covid-19 (72, 73) . as this review illustrates, vitamin d is not the only essential nutrient known to contribute to normal functioning of the immune system (2, 5, 74) . it has been suggested by some researchers that, in addition to the consumption of a well-balanced diet, other nutrients such as vitamin c, zn and the n-3 fatty acids epa þ dha at levels above the daily reference values, may help reduce nutritional gaps, support optimal immune functions and possibly reduce risk and consequences of infection (2, 5) . dietary approaches to achieve a healthy gut microbiota may also benefit the immune system (71) . in recent reviews of the therapeutic uses of vitamin d to prevent or treat arti, and data from human intervention trials on covid-19 patients, using pharmacological doses, there was no evidence of any specific therapeutic effect. however, both reports (34, 75) advised that all people should continue to follow the uk government advice on daily vitamin d supplementation of 10 μg/d to maintain bone and muscle health during the covid-19 pandemic, since people may not be getting enough from sunlight exposure or diet. in a further rapid review, the royal society (76) agreed that there is no direct causal link yet between vitamin d deficiency and increased susceptibility to covid-19. however, this report pointed out that the uk has one of the highest levels of vitamin d deficiency in europe and that it would be prudent for the government to provide a stronger public health message about avoiding vitamin d deficiency. despite social media attention and claims for high-dose therapeutic benefits of some nutrients, it is key to prevent false or misleading claims 2(5,6) that diet or individual micronutrients can either 'boost' the immune system or 'prevent' or 'cure' covid-19 infection. indeed, medicinal claims for prevention, cure and alleviation of a disease for foods and food supplements are illegal in the uk and the european union as a whole (77) . furthermore, consumption of excessive quantities of some micronutrients can have adverse metabolic and health effects, and total intakes of each nutrient from all food and food supplement sources must take into account the tolerable upper safe level set by expert scientific committees such as european food safety authority (78) , the food and nutrition board/institute of medicine in the usa (31, 47, 79) and the uk expert vitamin and mineral group (80) . in conclusion, avoidance of nutrient deficiencies, identification of target groups at high risk of suboptimal nutritional status and the use of practical, safe and effective nutrition policy solutions may help strengthen the resilience of people to the covid-19 pandemic. further research and the greater understanding of potential nutritional risk factors could help explain why certain groups of people are more susceptible to covid-19. the evolving information will contribute to the evidence base for dietary counselling on healthy weight and the role of the essential micronutrients in supporting immune functions, as well as for the development of clinical guidelines and effective public health strategies on nutrition and health. covid-19: death rate is 0.66% and increases with age, study estimates evidence that vitamin d supplementation could reduce risk of influenza and covid-19 infections and deaths rimmer a (2020) two thirds of healthcare workers who have died were from ethnic minorities making nutrition a priority to help reduce risk of infections and death during the coronavirus pandemic optimal nutrition status for a well-functioning immune system is an important factor to protect against viral infections vitamin d and sars-cov-2 virus/covid-19 disease concept of borderline vitamin deficiencies micronutrient status methods contribution made by biomarkers of status to an fp6 network of excellence, european micronutrient recommendations aligned (eurreca) executive summary -biomarkers of nutrition for development: building a consensus biomarkers of nutrition for development (bond) the vitamin d deficiency pandemic: approaches for diagnosis, treatment and prevention vitamin d deficiency: defining, prevalence, causes and strategies of addressing contribution of nutrition science to the vitamin d field -clarity or confusion? vitamin d deficiency 2.0: an update on the current status worldwide sacn vitamin d and health report vitamin d levels and deficiency with different occupations: a systematic review review: non-musculoskeletal benefits of vitamin d editorial: low population mortality from covid-19 in countries south of latitude 35 degrees north supports vitamin d as a factor determining severity evaluation of vitamin d 3 intakes up to 15,000 international units/day and serum 25-hydroxyvitamin d concentrations up to 300 nmol/l on calcium metabolism in a community setting controversies in vitamin d: summary statement from an international conference dietary supplement use at the population level: recent experience from the 1994-5 british national diet and nutrition survey: people aged 65 and over hospital mealtimes: action research for change? incidence and recognition of malnutrition in hospital nutritional issues in nursing home care protein energy undernutrition in hospital patients trace mineral intake and deficiencies in older adults living in the community and institutions: a systematic review age-related smell and taste impairment and vitamin d associations in the u.s. adults national health and nutrition examination survey vitamin d in renal transplantation -from biological mechanism to clinical benefits current evidence on vitamin d deficiency and kidney transplant: what's new? food and nutrition board & institute of medicine (1997) dietary reference intakes for calcium, phosphorus, magnesium, vitamin d and fluoride vitamin d supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data vitamin d status has a linear association with seasonal infections and lung function in british adults scientific advisory committee on nutrition (2020) rapid review: vitamin d and acute respiratory tract infections. sacn/post vitamin d concentrations, cardiovascular risk and events -a review of epidemiological evidence association between vitamin d deficiency and heart failure risk in the elderly vitamin d status, body mass index, ethnicity and covid-19: initial analysis of the first-reported uk biobank covid-19 positive cases (n 580) compared with negative controls controversial effects of vitamin d and related genes in viral infections, pathogenesis and treatment outcomes time trend and income analyses for years 1 to 9 vitamin d supplement use and associated demographic, dietary and lifestyle factors in 8020 south asians aged 40-69 years: analysis of the uk biobank cohort scientific opinion on dietary reference values for vitamin d vitamin d concentrations and covid-19 infection in uk biobank letter in response to the article: vitamin d concentrations and covid-19 infections in uk biobank results from years 7 and 8 combined of the rolling programme vegetarianism and veganism: not only benefits but also gaps dietary factors influencing zinc absorption dietary reference intakes for vitamin a, vitamin k, arsenic the role of zinc in antiviral immunity efficacy of zinc given as an adjunct to the treatment of severe pneumonia: a meta-analysis of randomised double-blind and placebo-controlled trials selenium, selenoproteins and viral infection role of selenium in health and disease: emerging and recurring trends a role for seleniumdependent gpx1 in sars-cov-2 virulence association between regional selenium status and reported outcome of covid-19 cases in china scientific opinion on the substantiation of health claims related to copper and protection of dna, proteins and lipids from oxidative damage (id 263, 1726), function of the immune system (id 264), maintenance of connective tissues (id 265, 271, 1722), energy-yielding metabolism (id 266), function of the nervous system (id 267), maintenance of skin and hair pigmentation (id 268, 1724), iron transport (id 269, 270, 1727), cholesterol metabolism (id 369), and glucose metabolism scientific opinion on the substantiation of health claims related to copper and reduction of tiredness and fatigue (id 272), maintenance of the normal function of the nervous system (id 1723), maintenance of the normal function of the immune system (id 1725) and contribution to normal energy-yielding metabolism scientific opinion on the substantiation of health claims related to iron and formation of red blood cells and haemoglobin (id 249, id 1589), oxygen transport (id 250, id 254, id 256), energy-yielding metabolism (id 251, id 1589), function of the immune system (id 252, id 259), cognitive function (id 253) and cell division vitamin effects on the immune system: vitamins a and d take centre stage maintenance of the normal function of the immune system (id 161, 163), maintenance of normal bone (id 164), maintenance of normal teeth (id 164), maintenance of normal hair (id 164), maintenance of normal skin (id 164), maintenance of normal nails (id 164), maintenance of normal cardiac function (id 166), maintenance of normal vision by protection of the lens of the eye (id 167), contribution to normal cognitive function (id 182, 183), regeneration of the reduced form of vitamin c (id 203), maintenance of normal blood circulation (id 216) and maintenance of a normal scalp the role of vitamin e in immunity vitamin e and respiratory tract infections in elderly nursing home residents: a randomised controlled trial age-associated changes in immune function: impact of vitamin e intervention and the underlying mechanisms vitamin c and immune function factors affecting vitamin c status and prevalence of deficiency: a global health perspective scientific opinion on the substantiation of health claims related to folate and blood formation (id 79), homocysteine metabolism (id 80), energy-yielding metabolism (id 90), function of the immune system (id 91), function of blood vessels (id 94, 175, 192), cell division (id 193), and maternal tissue growth during pregnancy scientific opinion on the substantiation of health claims related to vitamin b 6 and protein and glycogen metabolism (id 65, 70, 71), function of the nervous system (id 66), red blood cell formation (id 67, 72, 186), function of the immune system (id 68), regulation of hormonal activity (id 69) and mental performance scientific opinion on the substantiation of health claims related to vitamin b 12 and red blood cell formation (id 92, 101), cell division (id 93), energy-yielding metabolism (id 99, 190) and function of the immune system contribution of selected vitamins and trace elements to immune function folate deficiency inhibits the proliferation of primary human cd8 þ t lymphocytes in vitro european commission of the european union (2020) eu register of nutrition and health claims made on foods evidence synthesis and translation for nutrition interventions to combat micronutrient deficiencies with particular focus on food fortification 2020) nutrition, immunity and covid-19 vitamin d and inflammation: potential implications for severity of covid-19 optimisation of vitamin d status impact mortality from sars-cov-2 infection enhancing immunity in viral infections, with special emphasis on covid-19: a review national institute for health and care excellence (2020) evidence review: vitamin d for covid-19 the royal society (2020) vitamin d and covid-19: rapid review on the community code relating to medicinal products for human use oj l311 tolerable upper intake levels for vitamins and minerals dietary reference intakes for vitamin c, vitamin e, selenium and carotenoids food standards agency: expert group on vitamins and minerals (2003) safe upper levels for vitamins and minerals. london: food standards agency. nutritional status of micronutrients 7 the review and its preparation did not receive any funding from agencies in the public, commercial or not-for-profit sectors.d. r. and j. l. participated in all aspects of producing the review.d. r. is a member of several industrial scientific boards and is scientific adviser to a number of uk, european and international organisations. j. l. sits on the government's scientific advisory committee for nutrition. key: cord-276130-wjnwpn8f authors: bradley, ryan; schloss, janet; brown, danielle; celis, deisy; finnell, john; hedo, rita; honcharov, vladyslav; pantuso, traci; pena, hilda; lauche, romy; steel, amie title: the effects of vitamin d on acute viral respiratory infections: a rapid review date: 2020-08-03 journal: adv integr med doi: 10.1016/j.aimed.2020.07.011 sha: doc_id: 276130 cord_uid: wjnwpn8f nan from a variety of dosing strategies. future clinical trials on vitamin d should consider the sources of heterogeneity in the existing experimental research and design trials that account for baseline status, evaluate the potential for prevention and treatment in at risk populations, standardize dosing strategies, assess product quality, assess outcomes according to gold standard definitions/diagnostic methods, and delineate viral arti from other causes when possible. the available mechanistic evidence related to immunological requirements for adequate vitamin d, the availability of observational and experimental evidence suggestive of clinically meaningful benefits (especially in deficient/insufficient participants), and the high margin of safety, should make vitamin d a high priority for additional clinical research during the current covid-19 pandemic. vitamin d, is a fat-soluble, secosteroidal hormone available to humans in the diet, nutritional supplements, and via direct production in the skin upon exposure to adequate ultraviolet light. vitamin d has numerous fundamental functions in the innate and acquired immune response. activation of both t-and b-cells leads to upregulation of the vitamin d receptor (vdr), allowing for changes in expression of over 500 vitamin d related genes.[1-3] select mechanistic effects of vitamin d on immune function include: enhancement of chemotaxis and phagocytosis [4] , regulation of antibody production in b cells [5] , inhibition of interleukin (il)-2, interferon (ifn)-gamma, tumor necrosis factor (tnf)-alpha il-9, and il-22 [6] [7] [8] [9] [10] , and increased il-3, il-4, il-5, and il-10. [11] observational research in the british birth cohort has demonstrated significant linear relationships between serum vitamin d concentration (i.e., 25hydroxycholecalciferol or 25-ohd) and lower risk of acute respiratory tract infection (arti), with each 10 nmol/l increase associated with a 7% lower risk. [12] further observational research in the united states (us)-based national health and nutrition examination survey (nhanes) 2001-20016 suggested those with insufficient serum status (25-ohd<30 nmol/l [<20 ng/ml]) had 58% higher odds of arti. [13] based on the numerous roles of vitamin d in the regulation of immune function, and notable observational research suggesting potential effects on arti, numerous randomized controlled trials in adults and children have aimed to learn the direct effects of vitamin d on risk of arti and their potential complications. the purpose of this rapid review is to summarize available systematic reviews of randomized, controlled clinical trials of vitamin d on arti and related outcomes. what are the effects of vitamin d on acute respiratory tract infections (arti) and associated complications? inclusion/exclusion criteria reviews were included if they were described as "systematic" and exhibited methods consistent with systematic reviews (i.e., defined clinical question, detailed search protocol, etc.) and reported on human prospective intervention trials sampling adults and/or children with reported arti. reviews were excluded if they were designed as narrative j o u r n a l p r e -p r o o f reviews, non-review manuscripts, included only observational studies, and/or the study sample was not reported as diagnosed with arti. medline (ovid), embase (ovid), amed (ovid), and cinahl search terms (example) five search strategies were pursued and compiled as follows: coronavirus/ or respiratory tract infections/ or bronchitis/ or common cold/ or pneumonia, viral/ or (coronavir* or ncov or influenza or h1n1 or mers-cov or flu or bronchit* or cough or rhinosinusit* or rhinit* or common cold or (respiratory adj2 (infect* or illness or symptom* or acute or virus* or disease))).ti,ab,kw. #2: exp vitamin d/ or exp calcitriol/ or exp cholecalciferol/ or exp ergocalciferol/ or exp 25-hydroxyvitamin d 2/ or ("vitamin d$" or "vit d" or calcitriol$ or cholecalciferol or ergocalciferol or "25-hydroxyvitamin d 2").ti,ab,kw #3: systematic review/ or meta-analysis/ or systematic review as topic/ or meta-analysis as topic/ or review literature as topic/ or (systematic review or meta analy$ or metaanaly$).ti,ab,kw #4: comment/ or letter/ or editorial/ #5: (#1 and #2 and #3) not #4 screening titles and abstract screening and full text screening were completed by one reviewer and checked for accuracy by a second reviewer. similarly, data extraction was completed by a single reviewer and checked for accuracy by a second reviewer. any discrepancies were resolved by consensus. the critical appraisal tool for this rapid review was performed using the bmj best practice criteria for appraising systematic reviews (https://bestpractice.bmj.com/info/toolkit/learn-ebm/appraising-systematic-reviews/). the initial search resulted in 270 citations [medline (n=57), embase (n=154), amed (n=1), and cinahl (n=58)], after duplicates (n=68) were removed, 202 remained for title and abstract screening. based on title and abstract review, an additional 138 manuscripts were excluded as irrelevant due methodology (i.e., editorials, commentaries, and/or nonsystematic reviews), or broad outcome measures (i.e., not focused on arti outcomes). following abstract review, 36 manuscripts were excluded by full text screening due to methodological limitations not apparent in the abstracts (i.e., narrative reviews), leaving 28 manuscripts for detailed extraction. during detailed data extraction, 5 additional manuscripts were excluded due to inclusion of only observational studies, plus 3 additional exclusions included: an editorial (n=1), a poster citation (n=1), and a duplicate republished as a report (n-=1), leaving 20 for the final detailed j o u r n a l p r e -p r o o f extraction; see figure 1 . all citations were imported into covidence software (melbourne, australia) for title and abstract reviews. full texts were also imported into covidence for review and data extraction upon finalization of the manuscripts meeting inclusion criteria. from the appraisal, seven of the 20 reviews met all the requirements. the majority of the studies met most of the criteria in the appraisal tool, however, three reviews were determined to be very poor quality because they met four or fewer of the requirements. the quality of data from these reviews [14] [15] [16] in our conclusions and summaries. see table 1 for a summary of all included studies in the final, detailed review. of the 20 studies, 13 were systematic reviews and/or of meta-analysis [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] , 3 were systematic reviews of randomised controlled trials (rcts)[28-30], 2 were systematic reviews of various studies [14, 31] and 1 was a detailed narrative review of rcts (and therefore was included), despite low formal quality of design [15] . the 2 systematic reviews with various studies included rcts, cohort studies, case-control series, retrospective case studies and cross-sectional studies [14, 31] . the majority of reviews searched 3 or more databases with pubmed, embase, cochrane, cinahl and medline being the main ones [15, [17] [18] [19] [20] [21] [22] [23] [25] [26] [27] [28] [29] [30] [31] [32] . two studies only used one database, pubmed [14, 33] and 1 didn't specify the databases searched [16] . the study population and size, type of respiratory condition, form and dose, and administration route or screening of vitamin d varied across the studies reviewed. fourteen studies included all populations including children, adults and elderly [14-18, 20, 22, 23, 26-30, 32 ] and 5 reviews were conducted on children only [19, 21, 24 , 31], 1 was for pregnant women and children [25] and 1 for children and young men [33] . the number of studies included for the reviews on children included 26 in total, encompassing 12 rcts, 3 cohort, 2 cross-sectional and 9 case-control studies [19, 21, 24, 31] . the pregnancy and children review contained 22 studies including 4 rcts and 18 observational [25] while the children and young men review contained 10 rcts [33] . for the studies that included all populations, 222 studies were identified in the reviews. these included 171 rcts, 24 cohort studies, 8 case-control studies and 4 crosssectional [14-18, 20, 22, 23, 26-30, 32 ] . the 7 reviews which mainly focused on children comprised a total sample of 33,503 participants; of those reviews that reported allocation, there were 6,474 participants in intervention arms and 6,464 participants in placebo arms [19, 21, the reviews exclusive to children all used oral administration of vitamin d with 4 reviews reporting on administration of a dose ranging from 300 iu -2000 iu per day [19, 21, 24, 31] . in the 2 reviews exclusive to pregnant women plus children and young men plus children, the dose ranged from 800 iu-2000 iu daily [25, 33] . the oral doses for vitamin d in the reviews of all ages varied dramatically from 100 iu to 100,000 iu. see table 2 for dosage range included in each review. the measurement outcomes from the reviews varied; however, the primary outcome measure evaluated for this review was the incidence of artis (n=13) [14, 15, 17, 18, 20-23, 25, 27-29, 31 ]. the other main outcome measures included were: the association between vitamin d levels and arti risk (5 reviews) [16, 26, 32 , 33], pneumonia incidence (3 reviews) [14, 19, 24] , and frequency of hospitalization rates (2 reviews) [14, 24] . several individual reviews reported additional, less specific, outcomes including: frequency of doctor visits, [25], asthma exacerbations [25], incidence of influenza [14] , tuberculosis [15] and extra-skeletal disease [30] . of the 21 reviews, 15 concluded vitamin d was safe and has the potential reduce the risk of arti [15-18, 22, 23, 25, 27, 29-33] . the other 6 reviews each concluded that there was insufficient evidence to support the protective effect of vitamin d for artis [14, 19-21, 24, 28 ] . reviews supporting a protective effect of vitamin d and arti. clinical significance: despite several positive systematic reviews and meta-analyses, the available experimental evidence related to the effects of vitamin d on acute respiratory tract infection (arti) is plagued with heterogeneity and mixed quality, and therefore is insufficient to recommend vitamin d supplementation to the general population as a protective agent against arti. however, based on the evidence identified in this rapid review (including a high margin of clinical safety), combined with strong mechanistic rationale, the following recommendations can be made for those at risk of arti: 1. vitamin d status should be tested for those at risk of arti; 2. patients identified with deficiency or insufficiency should be supplemented with vitamin d until their status is normalized; and 3. daily dosing of vitamin d3 is preferred to 1 alpha,25-dihydroxyvitamin d3 suppresses proliferation and immunoglobulin production by normal human peripheral blood mononuclear cells modulatory effects of 1,25-dihydroxyvitamin d3 on human b cell differentiation the targets of vitamin d depend on the differentiation and activation status of cd4 positive t cells vitamin d: modulator of the immune system an update on vitamin d and human immunity mechanisms underlying the effect of vitamin d on the immune system the vitamin d analog, tx527, promotes a human cd4+cd25highcd127low regulatory t cell profile and induces a migratory signature specific for homing to sites of inflammation immunosuppressive actions of 1,25-dihydroxyvitamin d3: preferential inhibition of th1 functions vitamin d in autoimmune, infectious and allergic diseases: a vital player? lineage-specific effects of 1,25-dihydroxyvitamin d(3) on the development of effector cd4 t cells 25-dihydroxyvitamin d3 has a direct effect on naive cd4(+) t cells to enhance the development of th2 cells vitamin d status has a linear association with seasonal infections and lung function in british adults vitamin d status and acute respiratory infection: cross sectional results from the united states national health and nutrition examination survey vitamin d in the prevention of acute respiratory infection: a systematic review of clinical studies vitamin d and susceptibility to infection vitamin d supplementation beyond the second year of life: joint statement of the nutrition committee of the german society for pediatric and adolescent medicine (dgkj) and the german society for pediatric endocrinology and diabetology (dgked) vitamin d supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data non-skeletal health effects of vitamin d supplementation: a systematic review on findings from meta-analyses summarizing trial data vitamin d and lower respiratory tract infection in children: a systematic review and meta-analysis of randomized controlled trials effect of vitamin d3 supplementation on respiratory tract infections in healthy individuals: a systematic review and meta-analysis of randomized controlled trials vitamin d supplementation for the prevention of childhood acute respiratory infections: a systematic review of randomised controlled trials. the british journal of nutrition sr=systematic review, ma=meta-analysis, rct=randomized clinical trial, arti=acute respiratory tract infection, urti= upper respiratory tract infection, lrti=lower respiratory tract infection key: cord-290428-zrlqzbss authors: de faria coelho-ravagnani, christianne; corgosinho, flavia campos; sanches, fabiane la flor ziegler; prado, carla marques maia; laviano, alessandro; mota, joão felipe title: dietary recommendations during the covid-19 pandemic date: 2020-07-12 journal: nutr rev doi: 10.1093/nutrit/nuaa067 sha: doc_id: 290428 cord_uid: zrlqzbss optimal nutrition can improve well-being and might mitigate the risk and morbidity associated with coronavirus disease 2019 (covid-19), caused by the severe acute respiratory syndrome coronavirus 2 (sars-cov-2). this review summarizes nutritional guidelines to support dietary counseling provided by dietitians and health-related professionals. the majority of documents encouraged the consumption of fruits, vegetables, and whole grain foods. thirty-one percent of the guidelines highlighted the importance of minerals and vitamins such as zinc and vitamins c, a, and d to maintain a well-functioning immune system. dietary supplementation has not been linked to covid-19 prevention. however, supplementation with vitamins c and d, as well as with zinc and selenium, was highlighted as potentially beneficial for individuals with, or at risk of, respiratory viral infections or for those in whom nutrient deficiency is detected. there was no convincing evidence that food or food packaging is associated with the transmission of covid-19, but good hygiene practices for handling and preparing foods were recommended. no changes to breastfeeding recommendations have been made, even in women diagnosed with covid-19. in january 2020, the world faced an outbreak of coronavirus disease 2019 , caused by the severe acute respiratory syndrome coronavirus 2 (sars-cov-2). evidence of high human-to-human transmissibility of sars-cov-2 has made social isolation the best preventive measure to avoid the spread of covid-19. 1 this pandemic is substantially affecting lifestyles, healthcare systems, and national and global economies. social isolation is often an unpleasant experience that may have negative effects on mental health. 2 it has been suggested that, until quarantine ends, self-isolation is likely to cause psychological and emotional symptoms, 3 changes in mood and altered sleep or eating patterns, 4 worsening of chronic health conditions, weight gain, and increased use of alcohol, tobacco, or illegal drugs. optimal nutrition is one of the main determinants of health that can improve well-being and mitigate the harmful health consequences associated with social distancing by helping to prevent or control most chronic diseases (eg, diabetes, hypertension, and excess body weight/obesity); aid in the regulation of sleep and mood; and prevent fatigue. 5, 6 nutritional modulation of the immune system is also important across the age spectrum. during early childhood, breastfeeding can provide protection against infections and respiratory diseases, as breast milk contains antibodies, enzymes, and hormones that can offer health benefits. 7 in older adults, the group at most risk for covid-19, changes in dietary habits lead to significant alterations in immunity and inflammation, termed immunosenescence and inflammaging. 8 some nutrients, such as omega-3 polyunsaturated fatty acids and probiotics, have been linked to anti-inflammatory responses and enhanced resistance to upper respiratory tract infection. 8 in individuals infected with sars-cov-2, nutritional status is a crucial factor for optimal prognosis and can determine the clinical severity of covid-19. 9 dietary supplementation with selected vitamins (eg, a, b, c, and d), minerals (eg, selenium, zinc, and iron), and omega-3 fatty acids was suggested by zhang and liu 10 as a treatment option for covid-19 patients and as preventive therapy against lung infection. however, the use of micronutrient supplements to prevent infections remains questionable. since to date there is no vaccine or evidence-based treatment for covid-19, the optimization of nutrient intake through well-balanced meals and the use of good hygiene practices in food selection, preparation, and conservation is probably the most effective approach for managing the continuous risk of viral infection. to this end, dissemination of healthy eating guidelines for healthcare professionals and the general public is a crucial strategy. despite intense efforts by international nutrition organizations and other health-related societies to produce guidelines and advice related to the covid-19 pandemic, literature is still scarce. meanwhile, the general public has been bombarded with a vast array of nutritional information from governmental authorities, the dietary supplement industry, nutrition enthusiasts, healthcare professionals, and others on how to prevent covid-19. this information, however, may be conflicting or non-evidence based. therefore, a systematic search of guidelines and official documents related to nutrition and covid-19 was conducted. the search included information obtained from several countries affected by the pandemic as well as manuscripts identified in scientific databases. the goal was to address one main question: what nutritional advice is being offered for individuals in quarantine during the covid-19 pandemic? the aim of this review was to summarize nutritional guidance related to the novel coronavirus (sars-cov-2) in order to support dietary counseling provided by dietitians and healthcare professionals during this pandemic. this narrative review was carried out from december 2019 to april 2020, during the covid-19 pandemic. guidelines and official documents from governmental and nongovernmental health agencies or institutions worldwide, all providing recommendations on food and nutrition during the covid-19 pandemic, were eligible for inclusion. literature related to specific nutritional or pharmacological treatment of patients already infected was excluded. the descriptors "coronavirus," "covid-19," "covid" and "nutrition" or "diet" were used to search for guidelines, position papers, and official documents in the pubmed, scielo, cochrane, and google databases. the boolean operators "and" and "or" were used to combine the terms used in the literature search. publications in the following languages were searched: italian, english, spanish, and portuguese. two authors (j.f.m. and f.c.c.) conducted the search and screened all references independently in a 2-step process. all selected documents were retrieved, and duplicates were excluded. titles and abstracts were then screened to identify studies that potentially met the eligibility criteria. of the 48 documents retrieved, 13 were included in this narrative review. of these, 8 dietary recommendations were issued from nutrition societies and associations and 6 from national governments (australia, brazil, canada, italy, spain, united states). five guidelines from health organizations (food and agriculture organization of the united nations, world health organization, united nations children's fund, center for disease control and prevention, and european food information council) were included. a summary of the guidelines, main advice, and other information is provided in table 1 . [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] four major nutrition-related topics-overall dietary recommendations, dietary supplements, breastfeeding, and food hygiene-were identified. nearly 70% of the documents retrieved encouraged the consumption of fruits, vegetables, and whole grain foods. two nutrition societies, from italy and spain, 12, 22 recommended at least 5 servings of fruits and vegetables per day. diets rich in fruits and vegetables contain high maintain good hydration; consume at least 5 servings of fruit and vegetables per day; consume whole-grain products and legumes; choose low-fat dairy products (milk and fermented milks or yogurt); consume other foods of animal origin in moderation; consume nuts, seeds, and olive oil; avoid processed foods and fast food na na asbran (2020) 13 prioritize fresh or minimally processed foods; use oils, fats, salt, and sugar in small amounts when preparing meals; limit consumption and purchase of processed and ultraprocessed foods such as french fries, soft drinks, cookies, and ice cream, which are rich in empty calories; use all parts of fruits and vegetables in recipes; avoid buying commercially prepared meals that are rich in sodium, trans fat, and calories na before placing supplies in cupboards or pantries, wash the packaging with soap and water and spray with 70% alcohol or a chlorinated solution; fruits and vegetables that are stored in the refrigerator should be removed from packaging and sanitized beforehand; before consumption, raw fruits and vegetables should be washed under running water and sanitized with sodium hypochlorite, which should always be used diluted, as instructed on the packaging asn (2020) 14 the healthiest meals emphasize whole grains, vegetables, and fruits; meat portions should be smaller to limit intake of saturated fat; limit consumption of commercially prepared frozen dinners; stock up on nutrition-packed foods that will stay fresh for a week or longer na when grocery shopping, use a disinfecting wipe to wipe hands and grocery cart handle cdc (2020) 15 washing hands with soap (20 seconds) before preparing or eating food is important for general food safety; (continued) consume a healthy diet rich in fruit and vegetables, protein foods, and whole grains; there is no single food, supplement, or natural health product that will prevent, treat, or cure covid-19 women who choose to breastfeed should be allowed to do so after appropriate handwashing and while wearing a mask there is no evidence that covid-19 is spread through eating or touching raw fruits or vegetables; prior to consumption, fresh fruits and vegetables should be washed or scrubbed under cold, running, potable tap water; while there are no special precautions for storing food, handwashing after putting away purchased food and before preparing food is recommended; hands should be washed before and after food containers are washed eufic (2020) 19 appropriate intakes of copper, folate, iron, selenium, zinc, and vitamins a, b 6 , b 12 , c, and d play an important role in the immune system; in general, these nutrients should be obtained through foods supplements can be used to add nutrients to the diet in individuals who have specific challenges in meeting dietary requirements wash hands for 20 seconds with soap before and after preparing or eating foods; wash fruits and vegetables before eating; disinfect surfaces and objects before and after use; keep raw and cooked foods separate from each other; use different utensils/chopping boards for raw and cooked foods; cook and reheat foods to adequate temperatures (72 c for 2 min); there is no need to disinfect food packaging items fao (2020) 20 consume a healthy diet to support a strong immune system; eat a variety of foods within each food group; eat plenty of fruits and vegetables; consume a diet rich in whole grains, nuts, and healthy fats; limit intakes of fat, sugar, and salt; drink water regularly; limit consumption of alcohol; continue to practice good food hygiene; there is no evidence that covid19 can be spread through contact with purchased foods; store raw and cooked foods separately; keep food preparation surfaces clean; cook foods thoroughly; store food at safe temperatures; and use safe water and raw materials (continued) amounts of vitamins and minerals, including vitamins a, c, d, e, and b complex, as well as zinc and selenium, which are important modulators of the immune system. 26 in addition, fruit and vegetables are good sources of water, antioxidants, and fiber, all of which play a role in the control of hypertension, diabetes, and weight gain, some of the most important risk factors for covid-19 complications. 27 micronutrients contribute to immune function through a variety of pathways in both innate and adaptive immune responses. vitamins a, c, d, e, b 6 , and b 12 and zinc are important for the maintenance of structural and functional integrity of physical barriers (eg, skin, gastrointestinal lining, respiratory tract, and others) as well as for the differentiation, proliferation, function, and migration of innate immune cells. 28 meanwhile, vitamins c and e, along with zinc and selenium, protect against free radical damage during increased oxidative stress. vitamins a, c, d, e, b 6 , and b 12 and zinc and selenium support the adaptive immune response by influencing the differentiation, proliferation, and normal function of t and b cells. these nutrients also affect antibody production and function, 28 contribute to cell-mediated immunity, and support the recognition and destruction of pathogens. lastly, they have antimicrobial activity and regulate the inflammatory response. 28 approximately one-third of the identified guidelines mentioned at least one of these nutrients as being important for optimizing the immune system, placing special emphasis on zinc and vitamins c, a, and d. 11, 19, 22 adequate intakes of these micronutrients may be attained through a daily diet that includes meat, fish, lentils and beans, dairy foods, nuts, seeds, eggs, citrus fruits (eg, orange, lemon, grapefruit), kiwi, strawberries, and vegetables such as broccoli, cauliflower, pumpkin, spinach, sweet potato, and carrots. while vitamin d can be obtained from some dietary sources, it is mainly synthesized endogenously through exposure of the skin to ultraviolet b irradiation. in fact, sunlight exposure can increase serum vitamin d levels to the same extent as an oral dose of 250 to 625 lg of vitamin d. 29 the societ a italiana di nutrizione umana 22 recommended exposure to sunlight for 15 to 30 minutes every day to promote the synthesis of vitamin d. however, in latitudes outside 40 north and south, ultraviolet b radiation is greatly reduced during winter. as a result, an increased intake of vitamin d-rich foods, as well as vitamin d supplementation, might be necessary to maintain adequate serum levels in winter. 30, 31 almost, one-third of the organizations and societies recommended avoiding the intake of salt, fat, and sugar and encouraged reductions in sugary drinks, other sugar-rich products, meat portions, and other foods of animal origin to lower the intake of saturated fat. [12] [13] [14] in addition, they suggested that low-fat dairy foods and healthy fats (eg, olive oil and fish oil) be included in the diet 12, 23 and recommended sauces, spices, and herbs as salt substitutes. 17 over the last 30 years, the literature has described a definitive role of fat in immunity. saturated fatty acids act on toll-like receptor 4, a sensor that binds bacterial lipopolysaccharide and thus acts in the innate immune response. as a result, a high intake of saturated fatty acids favors low-grade inflammation. 32 on the other hand, monounsaturated and polyunsaturated fatty acids are known for their favorable immune-modulatory action. 33 omega-3 polyunsaturated fatty acids present in seafood, algal oil, marine fish, and flaxseed support the immune system by activating cells from both the innate and the adaptive immune systems, 34 while omega-9 monounsaturated fatty acids found in olive, sunflower, and safflower oils and nuts have antioxidant, antimicrobial, and antiviral effects. 35 for adult males and nonpregnant/nonlactating adult females, the recommended dosage of omega-3 polyunsaturated fatty acids (eicosapentaenoic acid plus docosahexaenoic acid) is 250 mg/ d. 36 this recommendation can be met by consuming at least 2 portions (90 g each) of fatty marine fish, such as mackerel, salmon, sardine, herring, and smelt, per week. 36 drinking water or maintaining adequate hydration was suggested in 3 documents, 12,20,24 but no guidance on water requirements (eg, cups or milliliters per day) was provided. the evidence in favor of a direct association between hydration status and health has been previously confirmed. water is essential for cellular homeostasis, kidney function, body temperature control, mood regulation, cognitive function, gastrointestinal and heart function, and headache prevention. 37 it is important to note that diets low in water and rich in salt can negatively impact kidney function. 38 in addition, the consumption of sugary drinks instead of water increases the intake of carbohydrates and calories, thereby raising blood glucose and exacerbating obesity and other related chronic diseases. because of their low water reserves, older adults can be affected more seriously by hypohydration. 38 furthermore, water intake comes mostly from beverages (about 75%) and food intake (about 25%), especially from fresh food such as fruits and vegetables. 38 therefore, advice on the importance of drinking water, tea, and milk and consuming other water-containing foods should be delivered by dietitians and healthcare professionals during the covid-19 pandemic. since the daily water requirement is influenced by age, sex, level of physical activity, diet, body composition, pregnancy, environmental conditions, and the presence of disease, the recommended intake of water varies widely and can reach 3.7 l/d for older adults (including all water contained in food, beverages, and drinking water). 39 according to the dietary reference intakes for water, potassium, sodium, chloride, and sulfate, 39 adults with moderate levels of physical activity who consume approximately 2200 kcal/ d can meet water recommendations by drinking 12 cups of water and beverages daily, while children require 4 to 5 cups per day, adolescents (9 to 18 years) 7 to 11 cups per day, and older adults 9 to 13 cups per day. while some organizations recommend choosing unprocessed foods, 12,13,22-24 healthy dried, frozen, or canned foods (eg, fish, fruits, soups) are suggested as alternatives when fresh produce is not available. 17, 23 there is a current trend for guidelines to support homemade and fresh meals instead of processed foods. several countries, including, brazil, 40 chile, 41 australia, 42 and canada, 43 have recommended limiting the intake of processed foods, which are linked to cancer, obesity, hypertension, and diabetes. 44 interestingly, there has been a worldwide trend for individuals to stock up on processed foods during the quarantine. this has been recommended by governmental agencies such as the centers for disease and control and prevention 45 for individuals at risk or for the general population by health canada 46 to avoid social contact during the peak of the covid-19 outbreak. it is likely that many individuals have stocked up on unhealthful food items that will eventually be consumed. therefore, clearer guidelines and recommendations about what foods to purchase are needed. although there is some lack of clarity and guidance regarding obesity as a risk factor for covid-19, 47 substantial preliminary data demonstrate that higher body mass index is a considerable risk factor for hospitalization and development of severe pneumonia. [48] [49] [50] [51] in fact, a systematic review and meta-analyses showed that 50% of the adult patients infected with the middle east coronavirus presented with hypertension and diabetes, while obesity was present in 16% of the cases. 52 moreover, a recent study found a significant inverse correlation between body mass index and age: young individuals admitted to hospitals were more likely to have obesity. the study suggested that obesity could shift the incidence of severe covid-19 disease to younger ages in countries where the prevalence of obesity is high. 48 obesity restricts respiration, weakens immune responses, and is proinflammatory. it is also associated with an increased risk of diabetes mellitus, cardiovascular disease, and kidney disease, all of which contribute to increased vulnerability to pneumonia-associated organ failure. 53 thus, healthy weight loss could be a good strategy to reduce the risk of covid-19 complications. although none of the institutions mentioned weight loss in their guidelines, 3 of them highlighted the importance of avoiding weight gain. specific guidelines for obese individuals are nonetheless needed to promote gradual weight loss without compromising the body's lean mass. considering the difficulty to achieve significant weight loss through physical activity during the pandemic, protein intake of around 30% of energy requirements may be considered for adults under energy-restricted diets. this level of protein intake can prevent or attenuate the loss of lean muscle mass while also promoting greater satiety during weight loss. 54 in their discussion of nutritional recommendations during covid-19 quarantine, muscogiuri et al 4 highlighted the role of tryptophan, an amino acid and a precursor of serotonin, in the regulation of satiety and caloric intake, suggesting protein-rich foods such as milk, yogurt, seeds, and nuts as good sources. it is worth noting that web-based weight-loss approaches are becoming popular and are effective for patients with obesity. 55 such tools may be useful during the covid-19 pandemic. probiotics were recommended by only one institution, 11 which did not provide a specific amount or examples of food sources. probiotics are defined as "live microorganisms that, when administered in adequate amounts, confer a health benefit on the host." 56 they can act through diverse mechanisms, including modulation of immune function, production of antimicrobial compounds and organic acids, improvement of gut barrier integrity, formation of enzymes, and interaction with resident microbiota. 57 studies of probiotic species belonging to the lactobacillus and bifidobacterium genera have shown promising results regarding improved immune function. 58 fermented dairy products might be a good option to improve the gut microbiota, although further studies are needed to better elucidate the modulatory mechanisms of the microorganisms in these foods. only one agency provided guidance on alcohol consumption. the food and agriculture organization of the united nations 20 recommended that alcohol intake be limited, but no specific amounts were provided. excessive alcohol consumption is associated with reduced host immunity to viral infections and increased susceptibility to tuberculosis and bacterial and viral pneumonia in humans and animals. 59 on the other hand, some benefits of moderate alcohol consumption have been reported, including reduced risk of cardiovascular disease, alleviation of acute stress, improved mood, and increased relaxation. 60 current guidelines for moderate intake recommend no more than 1 drink per day for women and no more than 2 drinks per day for men. 5 it should be noted that individuals who do not drink alcohol should not start drinking. finally, generic terms and phrases such as "healthy diet," "variety of foods in each group," "variety of fresh and unprocessed foods," and "varied diet" were observed in the majority of the documents. these messages might not be clear enough to encourage people to make healthy food choices. specific recommendations, including examples of food and instructions for food preparation, would improve the public health message. all documents reported that there are currently no known supplements to prevent covid-19. only 2 documents mentioned that it might be possible to use supplements to meet dietary recommendations. 11, 19 some vitamins and minerals improve immunity; however, the idea that more is better is a misconception. megadoses of vitamins and minerals can induce toxic and adverse effects 61, 62 or interact with medications, leading to enhanced or reduced pharmacological effects. 63 on the other hand, it is important to note that dietary reference intakes have been established for healthy individuals and are based on a diet providing 2000 kcal/d. 64 thus, healthcare professionals should individualize dietary plans by considering factors that can increase nutrient requirements, such as specific diseases/conditions, medications, dietary patterns (eg, vegetarianism), and exercise intensity. for this purpose, the range from the recommended dietary allowance to the tolerable upper intake level can be used to optimize the dietary plan. 65 the brazilian association of clinical nutrition 11 reported that vitamin c supplementation may be useful for individuals at risk of respiratory viral infections. vitamin c is a recognized antioxidant nutrient that can enhance chemotaxis, phagocytosis, generation of reactive oxygen species, and, ultimately, microbial killing. 66 however, a systematic review involving 10 708 participants showed that doses of vitamin c exceeding 1 g/d were not beneficial in reducing the incidence of colds among the overall population. 67 on the other hand, such doses might be effective in reducing the duration of colds by 8% to 18%. in addition, vitamin c may be useful to prevent the development of colds in people exposed to brief periods of intense physical activity 67 or to cold temperatures. 68 vitamin d is another antioxidant that has been associated with a reduction in pulmonary infections. 69, 70 evidence that vitamin d can prevent or treat influenza is inconclusive, 71 but vitamin d status has been associated with the severity of covid-19. 31 potential mechanisms include increased secretion of antimicrobial peptides, decreased production of chemokines, inhibition of dendritic cell activation, and altered t-cell activation. 72 none of the documents reviewed here suggested vitamin d supplementation as preventive therapy against covid-19. however, rhodes et al 31 suggested that countries south of latitude 35 north have low population mortality, which might indicate a role of vitamin d in determining outcomes from covid-19. when deficiency is detected, oral supplementation with doses between 2000 and 4000 iu/d is indicated. 11 although a higher dose has been recently proposed with the aim of reducing the risk of infection (vitamin d 3 , 10 000 iu/d for a few weeks to rapidly raise 25(oh)d concentrations, followed by 5000 iu/d), 73 this is still controversial and contradicts other recommendations. since it is not feasible to recommend biochemical analysis of vitamin d levels during a pandemic, targeting vulnerable populations for vitamin d supplementation can mitigate the health risks associated with covid-19, especially since vitamin d deficiency has been shown to correlate with hypertension, diabetes mellitus, obesity, and darker skin pigmentation. 29 although it may be controversial, vitamin d supplementation to prevent deficiency may, at the very least, provide benefits by sustaining bone mass during lockdown. zinc and selenium are antioxidant micronutrients often considered for supplementation. 11, 28 zinc is a cofactor of superoxide dismutase, an enzyme present in the mitochondria and cytosol of cells that suppresses oxidative stress. excess zinc, however, also causes cellular oxidative stress. 74 a narrative review showed ample evidence of the antiviral activity of zinc (10 mg/kg of body weight, up to 600 mg/d total) against a variety of viruses, such as influenza. 75 in addition, zinc is critical in generating both innate and acquired (humoral) antiviral responses. however, the authors concluded that further research is needed on the antiviral mechanisms and clinical benefits of zinc supplementation as a preventative and therapeutic treatment for viral infections. 75 a recent study suggested that the elderly are at risk for zinc deficiency, which increases susceptibility to infections such as pneumonia. zinc supplementation (ie, elemental zinc, 30 mg/d) might be adequate to improve immune function and to reduce the risk of infections in this group. 76 selenium has been found to increase the activity of glutathione peroxidase, another antioxidant enzyme, and to augment a number of host immune responses, including interferon c production, t-cell proliferation, antigen stimulation, and natural killer cell activity. 77 in fact, an experimental study with mice and influenza virus showed that selenium deficiency led to more severe disease and an increased proinflammatory immune response, resulting in increased pathology in the lungs. 78 selenium is an important trace element that can be found in nuts, breads, grains, meat, poultry, fish, and eggs and is easily obtainable from dietary sources (see the dietary recommendations section). in summary, it is preferable to obtain antioxidants from food rather than from supplements. however, supplements are recommended for individuals who have specific challenges in meeting dietary requirements. the key message regarding dietary supplements is that individuals should not rely on supplements to prevent covid-19. further studies into the effects of vitamin and mineral supplementation on outcomes related to covid-19 (eg, disease severity, inflammatory status, hospitalization, death, etc) are warranted. currently, several clinical trials on vitamin d (n ¼ 21), vitamin c (n ¼ 15), zinc (n ¼ 15), and selenium (n ¼ 1) supplementation are under way (www.clinicaltrials. gov). it is hoped that the results of these studies will lead to a better understanding of the relationship between micronutrients and covid-19. breastfeeding provides a multitude of benefits for both mother and child. breast milk contains important antibodies that benefit the child's immune system, protecting against viral and bacterial infections. 7 according to the world health organization, breastfeeding must be exclusive until 6 months of age (no water, other fluids, or solids) and continued until 2 years of age or beyond. 79 only 6 of the 13 documents included in this review addressed this topic. 15, 18, 19, 21, 23, 25 all recommended that breastfeeding be maintained during the covid-19 pandemic, even in women diagnosed with the disease. however, good hygiene practices are recommended, including mask wearing, handwashing before and after touching the infant, and disinfecting frequently used surfaces. approximately 54% of the documents selected for this review included guidance on food hygiene. 14, 16, [18] [19] [20] 23 there is currently no convincing evidence that food or food packaging is associated with the transmission of covid-19. 18, 20, 23 the risk of fecal-oral transmission, while low, 80 can persist even after viral clearance from the respiratory tract. this highlights the need for routine stool testing and transmission-based precautions for hospitalized patients 81 and probably for those recovering at home. all documents emphasized the importance of adequate personal hygiene when handling food, highlighting the need for frequent handwashing with soap and water or alcohol-based hand sanitizers. in food and beverage stores, the greatest risk of contamination is through contact with other people and "high touch" surfaces such as food scales, shopping-cart handles, and elevator buttons. 19 unlike some viruses that can live on food or other surfaces for several days, sars-cov-2 can survive on metal or plastic surfaces for 3 days and on cardboard surfaces for 1 day. 82 infectious disease authorities in several countries are recommending the use of soap or alcohol-based hand sanitizer for handwashing, reinforcing the importance of strict hygiene measures to prevent the spread of contamination. 80, 83 according to the european food safety authority, 19 there is no need to disinfect food packaging itself, as long as some precautions are taken: (1) wash hands for 20 seconds with soap and water before and after grocery shopping, unpacking foods, and after receiving delivered food; (2) maintain a safe distance (1 to 2 meters) from other people when shopping; (3) do not go shopping when sick; instead, when possible, order groceries online or have family members or friends help with shopping; (4) avoid touching foods unless you plan to buy them; (5) limit trips to the supermarket by planning meals; (6) cover your mouth and nose with a tissue or your sleeve when coughing or sneezing, and wash hands afterward; and (7) after touching surfaces, avoid touching your face, nose, and mouth until after hands have been washed. in contrast, the brazilian association of clinical nutrition 13 advocates the use of hygiene practices when handling food packaging of purchased items. they recommend washing food packages with soap and water and spraying with 70% alcohol or a chlorinated solution before storing them. fresh foods such as vegetables and fruits can be frozen after they are sanitized with sodium hypochlorite. blanching of vegetables is also suggested to reduce spoilage. the food and agriculture organization of the united nations 20 proposes the use of 5 core messages for safer food: (1) keep food clean; (2) separate raw and cooked foods; (3) cook food thoroughly; (4) keep food at safe temperatures; and (5) use safe water and raw materials. although sars-cov-2 can survive in water for a short time, the european food information council 19 has noted that the virus has not been detected in drinking water, which is generally subjected to several treatment steps, making both tap water and bottled water safe for human consumption and food hygiene. the main concern lies in low-to middle-income countries, where access to treated water may be limited or nonexistent. figure 1 describes the rationale behind the dietary guidance and the personal hygiene practices recommended during the covid-19 pandemic, along with the potential mechanisms linking diet and the prevention of covid-19 complications. this review summarizes recent scientific literature and existing recommendations from national and international nutrition agencies on an optimal diet, vitamin and mineral supplementation, and good hygiene practices for food preparation during the covid-19 pandemic. the findings can be used to help dietitians and healthcare professionals better address dietary recommendations during the covid-19 pandemic. guidance related to the safe handling of food, from production to consumption, is critical to reduce the risk of viral dissemination. the general recommendation is to consume a diet based predominantly on fresh foods such as fruits, vegetables, whole grains, low-fat dairy sources, and healthy fats (olive oil and fish oil) and to limit intakes of sugary drinks and processed foods high in calories and salt. dietary supplements (ie, vitamins c and d, zinc, and selenium) should be administered to individuals with, or at risk of, respiratory viral infections or in whom deficiency is detected. breast milk is the safest and healthiest food for infants, and breastfeeding should be encouraged, even in women diagnosed with covid-19. 19) pandemic. key nutrients that support the immune system can be obtained through dietary components that include fresh foods (eg, fruits and vegetables), fish, lean meat, dairy, water and other non-sugary beverages, and healthy fats. a healthy diet can also decrease the risk of, or help control, hypertension, diabetes, obesity, and muscle atrophy, which are all considered risk factors for covid-19 complications. there are no known supplements that can prevent covid-19; however, in populations at risk of deficiency, supplements can mitigate the public health risks associated with covid-19. breastfeeding benefits an infant's immune system, protecting against viruses and bacterial infections. the use of personal protection, such as masks, along with good hygiene practices, such as frequent handwashing with soap and water or alcohol-based sanitizers, can prevent covid-19 transmission and immune system impairment. symbol: (-): inhibitory effect. social distancing: keep your distance to slow the spread. centers for diseases control and prevention website the psychological impact of quarantine and how to reduce it: rapid review of the evidence sars control and psychological effects of quarantine nutritional recommendations for covid-19 quarantine us department of agriculture. dietary guidelines for americans mood and food breast feeding physical activity and diet shape the immune system during aging nutrition support in the time of sars-cov-2 (covid-19) potential interventions for novel coronavirus in china: a systematic review associac¸ão brasileira de nutrologia [brazilian association of clinical nutrition position of the brazilian association of clinical nutrition (abran) regarding micronutrients and probiotics in covid-19 infection academia española de nutrici on y diet etica (la academia) y el consejo general de colegios oficiales de dietistas-nutricionistas. recomendaciones de alimentaci on y nutrici on para la poblaci on española ante la crisis sanitaria del covid-19 associac¸ão brasileira de nutrologia [brazilian association of clinical nutrition guide to healthy eating in times of covid making health and nutrition a priority during the coronavirus (covid-19) pandemic coronavirus disease (covid-19) and breastfeeding. centers for disease control and prevention website food safety and coronavirus disease 2019 (covid-19) covid-19 tips and resources. dietitians australia website advice for the general public about covid-19 covid-19): what you need to know. european food information council website maintaining a healthy diet during the covid-19 pandemic ad interim indications of the italian society of neonatology endorsed by the union of european neonatal & perinatal societies nutrition advice for adults during the covid-19 outbreak. world health organization regional office for the eastern mediterranean website immune function and micronutrient requirements change over the life course does comorbidity increase the risk of patients with covid-19: evidence from meta-analysis a review of micronutrients and the immune system-working in harmony to reduce the risk of infection optimisation of vitamin d status for enhanced immuno-protection against covid-19 vitamin d status in the tropics: is sunlight exposure the main determinant? editorial: low population mortality from covid-19 in countries south of latitude 35 degrees north supports vitamin d as a factor determining severity the relation of saturated fatty acids with low-grade inflammation and cardiovascular disease immune dysfunction and increased oxidative stress state in diet-induced obese mice are reverted by nutritional supplementation with monounsaturated and n-3 polyunsaturated fatty acids effects of omega-3 fatty acids on immune cells potential health benefits of olive oil and plant polyphenols food and agriculture organization of the united states. fats and fatty acids in human nutrition acute and chronic effects of hydration status on health water, hydration, and health panel on dietary reference intakes for electrolytes and water. dietary reference intakes for water, potassium, sodium, chloride, and sulfate dietary guidelines for the brazilian population informe de evaluaci on de la implementaci on de la ley sobre composici on nutricional de los alimentos y su publicidad eat for health: australian dietary guidelines summary office of nutrition policy and promotion. the new food guide ultra-processed foods, diet quality, and health using the nova classification system what you can do coronavirus disease (covid-19): coronavirus disease (covid-19): measures to reduce covid-19 in your community covid-19 and obesity-lack of clarity, guidance, and implications for care obesity could shift severe covid-19 disease to younger ages factors associated with hospitalization and critical illness among 4,103 patients with covid-19 disease in new york city obesity and covid-19 severity in a designated hospital in shenzhen high prevalence of obesity in severe acute respiratory syndrome coronavirus-2 (sars-cov-2) requiring invasive mechanical ventilation prevalence of comorbidities in the middle east respiratory syndrome coronavirus (mers-cov): a systematic review and meta-analysis obesity and impaired metabolic health in patients with covid-19 effects of energy-restricted high-protein, low-fat compared with standard-protein, low-fat diets: a meta-analysis of randomized controlled trials web-based weight loss in primary care: a randomized controlled trial expert consensus document. the international scientific association for probiotics and prebiotics consensus statement on the scope and appropriate use of the term probiotic probiotics and prebiotics in intestinal health and disease: from biology to the clinic probiotic species in the modulation of gut microbiota: an overview a recent perspective on alcohol, immunity, and host defense health risks and benefits of alcohol consumption vitamins, are they safe? vitamin and mineral supplements: do we really need them? safety considerations and potential interactions of vitamins: should vitamins be considered drugs? subcommittee on interpretation and uses of dietary reference intakes. dietary reference intakes: applications in dietary assessment guiding principles for developing dietary reference intakes based on chronic disease hemil€ a h, chalker e. vitamin c for preventing and treating the common cold the effect on winter illness of large doses of vitamin c high-dose monthly vitamin d for prevention of acute respiratory infection in older long-term care residents: a randomized clinical trial vitamin d for prevention of respiratory tract infections: a systematic review and meta-analysis vitamin d and influenza-prevention or therapy? vitamin d effects on lung immunity and respiratory diseases evidence that vitamin d supplementation could reduce risk of influenza and covid-19 infections and deaths critical role of zinc as either an antioxidant or a prooxidant in cellular systems the role of zinc in antiviral immunity low zinc status: a new risk factor for pneumonia in the elderly? selenium, immune function and resistance to viral infections selenium deficiency and viral infection world health organization, department of nutrition for health and development. the optimal duration of exclusive breastfeeding. report of an expert consultation folha informativa-covid-19 (doenc¸a causada pelo novo coronav ırus organizac¸ão pan-americana da sa ude website evidence for gastrointestinal infection of sars-cov-2 aerosol and surface stability of sars-cov-2 as compared with sars-cov-1 united nations website key: cord-030992-ed0h045d authors: akhtar, saeed; das, jai k; ismail, tariq; wahid, muqeet; saeed, wisha; bhutta, zulfiqar a title: nutritional perspectives for the prevention and mitigation of covid-19 date: 2020-07-15 journal: nutr rev doi: 10.1093/nutrit/nuaa063 sha: doc_id: 30992 cord_uid: ed0h045d worldwide, there is an array of clinical trials under way to evaluate treatment options against coronavirus disease 2019 (covid-19), caused by the severe acute respiratory syndrome coronavirus 2. concurrently, several nutritional therapies and alternative supportive treatments are also being used and tested to reduce the mortality associated with acute respiratory distress in patients with covid-19. in the context of covid-19, improved nutrition that includes micronutrient supplementation to augment the immune system has been recognized as a viable approach to both prevent and alleviate the severity of the infection. the potential role of micronutrients as immune-boosting agents is particularly relevant for lowand middle-income countries, which already have an existing high burden of undernutrition and micronutrient deficiencies. a systematic literature review was performed to identify nutritional interventions that might prevent or aid in the recovery from covid-19. the pubmed, sciencedirect, cochrane, scopus, web of science, and google scholar databases were searched electronically from february to april 2020. all abstracts and full-text articles were examined for their relevance to this review. the information gathered was collated under various categories. deficiencies of micronutrients, especially vitamins a, b complex, c, and d, zinc, iron, and selenium, are common among vulnerable populations in general and among covid-19 patients in particular and could plausibly increase the risk of mortality. judicious use of need-based micronutrient supplementation, alongside existing micronutrient fortification programs, is warranted in the current global pandemic, especially in lowand middle-income economies. the recent coronavirus disease 2019 (covid-19) outbreak, caused by the severe acute respiratory syndrome (sars) coronavirus 2 (sars-cov-2), originated in china before becoming a global pandemic. as of june 23, 2020, more than 8,99 million cases of covid-19 and more than 469 587 covid-19-associated deaths were reported worldwide. the rate of new infections seemed to outpace both the scale of preparedness and the public health response, especially in resourceconstrained economies. 1 the covid-19 containment strategy implemented by countries like south korea, taiwan, and singapore offers an example for the rest of the world 2,3 but may be challenging for many countries. the possible emergence of new strains of sars viruses that cause flu-like disease, along with the measures needed to prevent the spread of such strains, has been reported in a number of retrospective studies. 4, 5 despite these alerts, the world was unprepared for the covid-19 pandemic. while current research is focused on the development of a vaccine and effective therapeutic agents, many scientists have also emphasized the importance of boosting the immune system through various nutritional interventions. 6 given the potential usefulness of bacillus calmette-gu erin (bcg) vaccine and the worldwide clinical trials initiated to counter the covid-19 pandemic, bcg vaccination has been suggested as a strategy to trigger immunity in patients with covid-19. 7, 8 moreover, the use of chloroquine and hydroxychloroquine as chemoprophylaxis in covid-19 has been extensively debated in the literature, although evidence is insufficient to recommend the routine use of any drug. agrawal et al 9 have comprehensively summarized the various ongoing clinical trials for chemoprophylaxis in covid-19, eg, nct04304053, nct04318444, nct04251871, nct04303507, nct04321174, nct04312243, and nct04308668. yao et al, 10 in an in vitro study, have validated antiviral activity elicited by these drugs against sars-cov-2. similarly, singh et al 11 proposed chloroquine and hydroxychloroquine to be potentially beneficial in the context of low-income and lowermiddle-income countries, especially in the absence of any effective treatment option against covid19. in their recent review, zhang and liu 12 examined a variety of treatment options for novel coronavirus infection, placing increased focus on the role of micronutrients as supportive and complementary components of treatment regimens. in a very recent report, grant et al 13 recommended vitamin d 3 intake at 10 000 iu/d for a few weeks, followed by 5000 iu/d until the serum 25(oh)d concentration reaches 100 to 150 nmol/l, as a preventive strategy against covid-19 among people at risk. there is existing evidence for the potential role of improved nutrition to augment the immune system. vitamins a, b complex, c, d, and e and many trace elements, such as iron, zinc, selenium, magnesium, and copper, have been shown to elicit immune-boosting properties, [14] [15] [16] and thus deficiencies of these micronutrients could be detrimental to immune function in viral infections. 17 likewise, supplementing diets with micronutrients has been reported as a way to improve or optimize immune function against viral infections; therefore, public health officials must consider nutritional interventions as a means to combat emerging viral infections. 6, 16 the scientific community, the various governments worldwide, and the global pharmaceutical industry, along with social and healthcare foundations and nongovernmental organizations, have endeavored to find a possible solution for covid-19, whether a medication or a safe vaccine, yet thus far their efforts have not borne fruit. the aim of this review is to highlight the potential role of nutrition in preventing and reducing the severity of covid-19, with a focus on the role of various micronutrients. micronutrients are dietary components that may contribute substantially to a robust immune system. 18 essential micronutrients like vitamins a, d, e, c, b 6 , b 12 , and folate and trace elements such as iron, zinc, and selenium, available in a variety of fresh animal-and plantbased foods, aid the body's ability to fight infections. 19, 20 health and survival are increasingly dependent on the functioning of the immune system. mechanistically, a rapid innate immune response occurs through phagocytes when a pathogen assaults the living system, but an adaptive immune response more specifically identifies the invading pathogen. basically, these immune responses are controlled and coordinated by t cells, which recognize the antigens and are classified as cytotoxic t cells. cytotoxic t cells kill infected, damaged cells and the t helper cells th1 and th2. these cells are involved in antiviral and cellular immune responses ( figure 1 ) as well as humoral and antiparasitic responses. 21 a strong immune system ensures host defense against pathogens and neoplastic cells, and balanced nutrition augments the immune system to provide optimal defense against infectious agents. childs et al 18 explained the critical role of the immune system as well as the defense mechanisms involved in protecting the body from invading agents, particularly in the presence of appropriate nutrition. thevarajan et al 22 reported their findings on the kinetics of the immune response to covid-19, describing higher concentrations of follicular helper t cells, antibody-secreting cells, activated cd4 þ and cd8 þ t cells, and immunoglobulin m (igm) and immunoglobulin g (igg) antibodies, all of which were observed to bind to coronavirus sars-cov-2. the results thus validate the role of a strong immune defense in patients covid-19. an optimally functioning immune system is closely linked to an adequate supply of micronutrients to the body, while severe deficiencies of these micronutrients lead to weakened immune responses and vulnerability to infections. vitamins a, c, e, and b complex, along with folic acid, zinc, selenium, iron, and copper, all play important roles in boosting the immune system of the population. 16, 23 several studies have confirmed that micronutrient deficiencies are associated with a weakened immune system that predisposes individuals to increased vulnerability to infections. 24, 25 gombart et al 16 demonstrated the critical role of essential vitamins and trace elements in boosting the immune system. they emphasized that micronutrients such as vitamins a, b 6 , b 12 , c, d, and e, (figure 2 ) in addition to iron, selenium, and zinc (table 1) , [26] [27] [28] [29] [30] [31] [32] [33] [34] [35] [36] might work synergistically to help immune cells function appropriately. recent research also supports a role of certain minerals and vitamins as adjunct therapeutic agents to treat microbiological infections as well as immunological and nonimmunological chronic diseases ( table 2) . [37] [38] [39] [40] [41] [42] [43] [44] [45] more recently, calder et al 6 reviewed the association between optimal nutrition and the immune system in providing better protection against viral infections. they suggested that essential micronutrients and the omega-3 fatty acids eicosapentaenoic acid and docosahexaenoic have the capacity to boost immunity against viral infections. similarly, chaturvedi et al 46 described the complex relationship between trace elements and viral infections, highlighting the immunomodulatory properties and antiviral activities of certain micronutrients such as iron, zinc, selenium, and copper. apart from functioning as antioxidants, these trace elements were shown to inhibit viral replication in host cells. sufficient literature suggests that vitamin and mineral supplementation in conjunction with a balanced and diversified diet can be used to meet the recommended dietary allowance (rda) for essential micronutrients. further studies have proposed supplementation with vitamin c 47,48 beyond the rda, ie, above 0.2 g/d, as a strategy to reduce both upper and lower respiratory tract infections among older patients. in a recent report, grant et al 13 speculated that doses of vitamin d 3 above 10 000 iu/d may be useful for treatment of patientswith covid-19. vitamin a is capable of defending the body against a variety of infections, primarily by regulating the proliferation and differentiation of immune cells. supplementation with preformed vitamin a has been suggested to downregulate the secretion of proinflammatory cytokines like tumor necrosis factor a and interleukin 6 in response to infections. 49, 50 the anti-infective role of vitamin a has been described in a number of studies that suggest all-trans retinoic acid to function via the nuclear retinoid acid receptor. 51, 52 retinoic acid has also been shown to exhibit immune-regulating properties, notably in humoral defense in viral infections. 53 vitamin a is essential for maintaining normal bodily functions, including defense against infections. an inadequate intake of vitamin a-rich food results in vitamin a deficiency, thus necessitating supplementation. in chickens infected with infectious bronchitis virus, a type of coronavirus, there was a marked difference in plasma retinol, retinol-binding protein, albumin, and transthyretin levels between those fed vitamin a-adequate diets and those fed marginally deficient diets. 54, 55 the protective role of vitamin a supplementation against a variety of infections such as malaria, lung infections, and hiv has been widely reported in the literature. 49 in addition, the compromised efficacy of inactivated bovine coronavirus vaccine was attributed to vitamin a deficiency in infected calves. 56 evidence further suggests that vitamin a supplementation in children reduces deaths associated with diarrheal and respiratory diseases. 57, 58 supplementation with preformed retinoids at a dose 100 times higher than the rda, ie, up to 500 000 iu, may cause hypervitaminosis in adults, while an intake of more than 10 000 iu of preformed vitamin a in first 60 days after conception may cause congenital abnormalities in infants. 59 in the current covid-19 pandemic, researchers have suggested vitamin a supplementation as part of a tailored multivitamin solution to satisfy the rda as a promising option to combat covid-19 in noncritical patients. 12,60 as cofactors to enzymes, b vitamins are central to the formation of, and the energy metabolism in, certain organic molecules. multiple studies have suggested a significant role of b vitamins, eg, folic acid, b 12 , and b 6, in the function of the immune system. these vitamins have the ability to operate as one-carbon donors in nucleotide synthesis, and one-carbon metabolism is involved primarily in complex biochemical pathways that are responsible for donating and regenerating onecarbon units. natural killer cells and cytotoxic cd8 þ lymphocytes are also influenced by these vitamins; hence, a balance of b 12 and folate must be maintained for immune responses. 61, 62 vitamin b 6 in the form of pyridoxal phosphate is particularly important, playing an active role as a cofactor in at least 160 catalytic pathways, with some metabolites shown to exhibit immunemodulating properties. 63, 64 scientific reports validate the significant role of vitamin b in normal function of the immune system, including the direct regulatory effects of vitamin b on immune response. 65, 66 among its myriad immunepromoting features, vitamin b 3 has been shown to inhibit neutrophil infiltration in the lungs, indicating an anti-inflammatory effect during ventilator-associated lung injury. 67 zhang and liu 12 reported that deficiency of b vitamins negatively influences the immune system and suggested that supplementation with b vitamins provides defense against viral infections. deficiency of b vitamins has been shown to weaken the host immune response; hence, b vitamins may have a role in enhancing the immune system of covid-19 patients. a plethora of scientific literature supports the role of vitamin c as an immune booster. besides exerting antioxidant activity, supplementation with ascorbic acid significantly affects epigenetic regulation and cell signaling. 19 the potential role of vitamin c as an antiviral agent against coronavirus has been observed in animal models by atherton et al. 68 carr and maggini 14 outlined several immune-supporting features of vitamin c, including involvement in phagocytosis, antibody production, growth and functioning of immune cells, and transitioning of leukocytes at infection sites. there is also evidence for the role of vitamin c as a weak antihistamine agent to reduce symptoms of stuffy nose and swollen sinuses. 69 an ameliorative role of vitamin c supplementation in upper respiratory tract infections has been well described in numerous studies. 47, 70, 71 vitamin c has shown potential to restore the damage caused by impaired phagocytosis and respiratory burst. 14 it is also proven to reduce the duration and severity of the common cold in adults and children. 47 high-dose intravenous vitamin c, administered at 50 to 200 mg/kg/d as treatment in patients with virus-induced acute respiratory distress syndrome on extracorporeal membrane oxygenation, was reported by fowler et al. 72 previous studies have shown that vitamin c supplementation is associated with reduced incidence of pneumonia and lower respiratory tract infections and also offers protection against coronavirus infection by boosting the immune system. 73, 74 zhang and liu 12 suggested supplementation with vitamin c to reduce the incidence of severe lower respiratory tract infections, such as pneumonia, and as a treatment option for covid-19. the study by hemil€ a 73 considers the findings of 3 controlled trials in humans, wherein vitamin c supplementation at doses between 0.05 and 2 g/d were reported to result in significantly fewer cases of pneumonia. in general, no adverse effects of large doses of intravenously or orally administrated vitamin c have been documented, except in patients with glucose 6-phosphate deficiency, renal insufficiency, or renal failure. 75, 76 vitamin d vitamin d receptors are present on monocytes, macrophages, t-and b-lymphocytes, and other immune cells. the 25(oh)d-1a-hydroxylase available on these cells converts 25-hydroxyvitamin d [25(oh)d] to its active form, 1,25-dihydroxyvitamin d. 77 vitamin d status is correlated with several autoimmune and inflammatory diseases. evidence of this association could be demonstrated by the north-south gradient observed with respect to the prevalence of diabetes mellitus type i, inflammatory bowel disease, and multiple sclerosis, suggesting reduced intracutaneous synthesis of vitamin d at higher latitudes. 78, 79 vitamin d has the ability to foster differentiation of monocytes to macrophages, which destroy invading agents. the formation of special antimicrobial proteins is regulated by certain vitamin d metabolites, and these antimicrobial proteins play a substantial role in combating infections, including lung infections, by destroying pathogens. 80, 81 respiratory tract infections can severely exacerbate chronic diseases, leading to increased risk of death. vitamin d can act through several mechanisms to decrease the risk of respiratory infections, including pneuomonia. 13 these findings are supported by the findings of zhou et al, 82 whose meta-analysis suggests that vitamin d deficiency is associated with a heightened risk of pneumonia. a meta-analysis of individual participant data showed that vitamin d supplementation is safe and protective against acute respiratory tract infection and is most beneficial in patients with vitamin d deficiency. 15 caccialanza et al 60 recently proposed supplementation with 25 000 iu or 50 000 iu of cholecalciferol per week to noncritical covid-19 patients with serum 25-hydroxycholecalciferol levels of 20 to 30 ng/ml or 20 ng/ml, respectively. likewise, grant et al 13 suggested administrating 10 000 iu of vitamin d 3 per day to prevent infection among individuals at risk of influenza or covid-19. vitamin d 3 supplementation also seems to decrease mortality in elderly people living independently or in institutional care. 83 recent data from countries like china have demonstrated a high number of covid-19-infected individuals to have low serum 25(oh)d levels. 12 likewise, fortification of foods with vitamin d is lacking in these countries, likely leading to vitamin d deficiency. 84, 85 a correlation between increased incidence of covid-19 and insufficient vitamin d concentrations in patients was further supported by zhang and liu, 12 who confirmed that middleaged to elderly people recently affected by covid-19 in china had low vitamin d levels. however, zisi et al 86 has highlighted the need to validate whether vitamin d supplementation is beneficial for covid-19 patients, as conflicting results were noted in some studies, while grant et al 13 suggested vitamin d supplementation as a therapeutic option for the treatment of covid-19. as a potential antioxidant, vitamin e has the capacity to protect cells and their functional components from injury caused by the release of reactive oxygen species that occurs during immune reactions to invading pathogens in respiratory infections. 87 vitamin e is involved in multiple aspects of the immune response, including phagocytosis, the production of antibodies, and t-cell proliferation. the role of vitamin e supplementation in enhancing t-cell function is well documented in the literature. 88 vitamin e has a direct effect on t cells. 89 trace minerals are an essential component of the diet. their regulatory effects on immune function have been well defined, and inadequate levels of trace elements have been reported to alter immune competence in humans. 94, 95 prolonged dietary deficiencies of trace minerals may result in impaired immune function by influencing one or more components of the immune system. 96 although the specific functions of minerals in protecting or boosting human immunity are not well understood, several trace elements such as zinc, magnesium, iron, copper, selenium, and manganese have gained wide recognition for their roles in maintaining optimal health. zinc, as a cofactor, is an integral component of more than 300 enzymes that exert secondary effects on the human immune system. 97 effects of zinc on the immune system are multifaceted. for example, in vivo studies on zinc deficiency have unveiled weaker immunological responses, as evidenced by reduced recruitment of neutrophils and decreased neutrophil chemotaxis, which might result in impaired function of natural killer cells, poor phagocytic activity by macrophages and neutrophils, and rapid production of reactive oxygen species, ie, oxidative burst. 98 the impact of zinc on immune mediators like enzymes, cytokines, and thymic peptides has also been reported, suggesting that recommended dietary intake or supplementation of zinc is essential to prevent functional loss. 99 zinc deficiency in the elderly can lead to decreased or diminished t-cell response, reduced natural killer cell activity, and depressed thymic hormone levels, thus creating substantial risk for respiratory infections and their associated morbidity and mortality. [99] [100] [101] [102] zinc supplementation has also been suggested to reduce the incidence of lower respiratory tract infections in zincdeficient children, 103, 104 and zinc administration within 24 hours of the onset of symptoms reduces the duration of common cold symptoms. 105 zinc at doses of more than 75 mg/d has been suggested to have promising antiviral effects against common cold viruses, including influenza viruses, with significant reductions in the duration of the common cold reported. 106 mild adverse effects of zinc supplementation have been reported with dosages above 200 mg/d 107, 108 ; hence, relatively lower dosages may also reduce the severity of covid-19. increasing the intracellular levels of zinc with zinc ionophores can effectively impair the replication of viral rna. studies have illustrated the effectiveness of zinc combined with pyrithione at lower concentrations, ie, 2mm zn 2þ and 2mm pyrithione, in inhibiting sars coronavirus. 109 a recent report by zhang and liu 12 provides support for the immune-promoting properties of zinc, suggesting that zinc supplementation can ameliorate covid-19-induced diarrhea and respiratory symptoms, ie, cough, sore throat, and shortness of breath. the synergistic effect of oral zinc sulfate together with bcg vaccine has been well described in the literature, providing a promising immunotherapeutic approach in communities increasingly prone to infection with the sars-cov-2 virus. 8 the substantial role of iron in the immune response has been widely documented in the literature, with iron deficiency shown to lead to impairment of the host immune system. studies have suggested that iron levels in humans must be carefully controlled to limit the availability of iron to pathogens, since iron regulates the growth and activity of a wide range of microorganisms, including viruses. even though some information on iron regulation in covid-19 patients is currently available, liu et al 110 have suggested limiting the iron supply to covid-19 patients in order to inhibit viral replication and reduce the risk and severity of infections. iron overload in the host creates oxidative stress that increases the risk of virus mutation. 111 mullick et al 112 considered the immune-modulating effect of iron and its deficiency to be a potential risk factor for the development of recurrent respiratory tract infections, a notion later confirmed by jayaweera et al. 113 adequate iron intake influences the innate immune response of the host by mediating the nuclear factor jb (nf-jb) and interferon c (ifn-c) signaling pathways in macrophages. the metal enhances the host's ability to resist intracellular pathogens. 114 iron deficiency leads to a t-cell-mediated immune response that may be associated with reduced activity of ribonucleotidyl reductase, which in turn regulates dna synthesis. iron-binding proteins like transferrin and lactoferrin have been shown to have a high affinity for metal ions. thus, ironbinding proteins do not merely lower free iron in infections but may also exhibit bactericidal properties. 115 a recent report by wessling-resnick 116 suggested the aforementioned mechanism as an innate immune response in humans that controls iron metabolism by limiting the availability of iron in infections. higher concentrations of free iron are reported in people with protein energy malnutrition. such concentrations are potentially linked to lower levels of transferrin, suggesting prudent use of oral iron therapy in infected individuals with anemia. 115 in contrast to the recommendation of liu et al 110 to restrict iron supply in covid-19 patients, recent updates on the management of anemia in high-risk covid-19 patients like pregnant women and cancer patients suggest iron replacement therapy as a more promising approach than transfusion to promote erythropoiesis. 117, 118 worsening of anemia concurrent with covid-19 in hospitalized premenopausal women not in the intensive care unit was reported to necessitate iron replacement therapy as a viable treatment approach to prevent transfusion-associated complications. 117 selenium selenium, present within selenoproteins in humans, influences cellular function by regulating redox-active proteins, antioxidant activity, and thyroid hormone metabolism. 119 the majority of the 25-member family of selenoproteins function as enzymes to catalyze redoxbased reactions. however, some selenoproteins do not exert enzymatic activity; for example, selenoprotein k plays an essential role in the activation and proliferation of immune cells. 120 selenium, as selenoproteins, supports efficient functioning of both the adaptive and the nonadaptive immune systems. 121, 122 selenium deficiency is characterized by a reduced rate of mitogeninduced lymphocyte proliferation, while leukotriene b4 synthesis, essential in neutrophil chemotaxis, is also impaired. several studies reported selenium-deficient study participants to have a weakened humoral immune response, as demonstrated by decreased igg and igm titers. 26, 119, 121, 122 dietary selenium deficiency increases oxidative stress, which in turn increases the virulence of benign or mildly pathogenic viruses (eg, influenza viruses) by genetic mutation and impairs the immune response. [123] [124] [125] selenium also acts as an antioxidant for a group of enzymes that inhibit the production of free radicals and prevent oxidative damage to host cells. 125 ma et al 126 reported an increased antibody response in chickens immunized with a live bivalent vaccine of newcastle virus and infectious bronchitis virus administrated in conjunction with selenium and ginseng stem-leaf saponins (se-gsls), suggesting that se-gsls enhances both the proliferation of lymphocytes and the production of interleukin 4 and ifn-c. consistent with the above reports of the antiviral effects of selenium, a recent update on the correlation between selenium status, determined by measurement of selenium concentrations in hair, and the covid-19 cure rate in a city population showed a significant association between poor selenium status and lower cure rates in covid-19 patients. 127 nevertheless, more individual-level data are needed to establish an association between infection severity and selenium status. selenium supplementation in selenium-deficient patients, particularly those who are elderly, may be an effective option for treating covid-19 and preventing or reducing its severe outcomes. polyunsaturated fatty acids (pufas), like selenoproteins, also exert major effects on both the innate and adaptive immune systems. in addition to their role as a constitutive part of the cell membrane, omega-3 pufas and their derivatives act as signaling molecules. 128 metabolites of omega-3 and omega-6 pufas are known as proresolving mediators, which are classified as prostaglandins, protectins, thromboxanes, resolvins, leukotrienes, and maresins. the synthesis of these metabolites is managed by a group of enzymes that include lipoxygenase, cyclooxygenase, and cytochrome p450. 129, 130 omega-3 pufas, mainly a-linolenic acid, docosahexaenoic acid, and eicosapentaenoic acid, inhibit the activation of immune cells while also supporting specific immune functions like phagocytosis and neutrophil differentiation. this suggests that omega-3 pufas do not repress nonspecific immunity. 128 protectin d1, an omega-3 pufa-derived lipid mediator, has been reported to markedly attenuate replication of influenza virus. 131 morita et al 131 suggested that protectin d1 levels were inversely related to the pathogenicity of influenza viruses (eg, h5n1). infected mice treated with protectin d1 plus peramivir were completely rescued from death due to influenza. in light of these findings on the role of pufa derivatives in mediating immune function, omega-3 pufa metabolites like protectin d1 may be useful as supportive dietary therapy for prevention and treatment of flu-like viral infections, including covid-19. immunosenescence, or the progressive deterioration of the immune response in aging, affects both innate and adaptive immunity in various pathological conditions, resulting not only in increased susceptibility of older adults to infections but also a reduced response to various treatment regimens, including vaccines. 132, 133 in 2019, the worldwide population of persons over 65 years of age was 703 million. of this number, 260 million were from east asia and south-east asia, and more than 200 million were from europe. 134 undoubtedly, immunocompromised older adults with additional comorbidities constitute a population at high risk of infection and severe morbidity. more drastic outcomes have been observed during the ongoing covid-19 pandemic: data confirm older adults as the most vulnerable population, with mortality reaching up to an estimated 15%. 135, 136 older adults, compared with younger populations, are more susceptible to covid-19-like viral infections and their associated serious outcomes. this increased susceptibility is attributable to aging-associated physiological changes, a weakened immune response, malnutrition, and multimorbidities. 137 prolonged hospitalization to ensure the stabilization and recovery of covid-19 patients increases the risk of malnutrition and severe loss of lean body mass and muscle function. nutritional screening and treatment of malnutrition in older patients is therefore mandated as part of covid-19 patient care. 138 a recent cross-sectional study from wuhan, china, reported that 52.7% of the 182 older adult patients with covid-19 were malnourished, with the mean mini nutritional assessment score being below 17. 139 advanced age is associated with a high risk of nutritional frailty, characterized by sudden weight loss, loss of lean body mass, and loss of physiological nutritional reserves. nutritional frailty compromises an individual's ability to meet their nutritional needs and increases their susceptibility to disability. 140 the european society for clinical nutrition and metabolism 138 proposed several considerations for the nutritional care of older covid-19 patients: nutritional screening; optimization of nutritional status by dietary counseling; supplementation with essential vitamins and minerals, oral nutritional supplements, and enteral and parenteral nutritional support when nutritional needs are not met; and regular physical activity in quarantine. adverse clinical outcomes of viral infections have been linked to low intakes of micronutrients. thus, providing the rda of vitamins a, d, e, c, b 6 , and b 12 and iron, zinc, selenium, and omega-3 pufas to malnourished older adults may help prevent or treat adverse clinical outcomes of covid-19. with the current emphasis on exploring therapeutic options to treat covid-19, more than 100 clinical trials are under way to develop a vaccine, design effective drugs, and test novel and repurposed compounds against sars-cov-2. however, data from longitudinal and observational studies on the extent of micronutrient deficiencies in covid-19 patients, along with infection severity scores, are needed. factors predicted to be associated with high risk of severe covid-19 include age above 50 years, male gender, smoking, chronic kidney disease, diabetes, cardiovascular disease, chronic obstructive pulmonary disease, and cerebrovascular disease. individuals with these risk factors should be screened for micronutrient deficiencies. supplementation to achieve adequate serological levels of the deficient nutrients may be provided in accordance with in-practice guidelines. the impact of supplementation should be evaluated relative to reductions in the severity of infection and improvements in the recovery index. the role of optimal nutrition for managing the current covid-19 pandemic cannot be underestimated. nutrition has a demonstrable role in the prevention and treatment of moderate to severe respiratory and nonrespiratory infections. adequate nutrition is even more essential for marginalized communities and in low-and middle-income countries, where deficiencies in key vitamins and minerals expose individuals to greater morbidity and mortality. low-and middleincome countries should strategize to ensure the population at large has access to optimal nutrition to boost the immune system and should provide specific supplementation for treatment of covid-19 patients, especially those with severe disease. older adults represent a high-risk population and may be prioritized to receive care in nursing facilities and to receive specialized nutritional support to improve physical and mental outcomes of the covid-19 pandemic. author contributions. s.a and t.i. conceived the review and drafted the paper. all authors provided input for the draft of the manuscript. w.s. performed the literature review and organized the results. z.a.b. and j.k.d. read the paper critically and contributed important revisions. m.w. designed the figures. funding/support. no external funds supported this work. declaration of interest. the authors have no relevant interests to declare. jr coronavirus disease: in-home isolation room construction characteristics of and important lessons from the coronavirus disease 2019 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polyunsaturated fatty acids the lipid mediator protectin d1 inhibits influenza virus replication and improves severe influenza aging and influenza vaccine-induced immunity age-related decline in immunity: implications for vaccine responsiveness united nations, department of economic and social affairs, population division prevention of covid-19 in older adults: a brief guidance from the international association for gerontology and geriatrics (iagg) asia/oceania region editorial: covid-19 and older adults clinical course and risk factors for mortality of adult inpatients with covid-19 in wuhan, china: a retrospective cohort study espen expert statements and practical guidance for nutritional management of individuals with sars-cov-2 infection prevalence of malnutrition and analysis of related factors in elderly patients with covid-19 in wuhan nutritional frailty, sarcopenia and falls in the elderly key: cord-271968-92p8dmha authors: polzonetti, valeria; pucciarelli, stefania; vincenzetti, silvia; polidori, paolo title: dietary intake of vitamin d from dairy products reduces the risk of osteoporosis date: 2020-06-10 journal: nutrients doi: 10.3390/nu12061743 sha: doc_id: 271968 cord_uid: 92p8dmha background: vitamin d and calcium are important dietary compounds that affect bone mass, even if other minerals (potassium, zinc, etc.) and vitamins (a, c and k) are also involved. vitamin d and certain minerals, in fact, play an important role in calcium homeostasis and calcium absorption. hip fracture incidence is higher in europe and the united states, where calcium is frequently included in the human diet; while the occurrence of these fractures is lower in developing countries, where diets are often poor in calcium. this condition is named the “calcium paradox”, and may be partially explained by phosphate toxicity, which can negatively affect mineral metabolism. it is important to maintain correct dietary calcium-phosphate balance in order to have a healthy life, reducing the risk of osteoporotic fractures in older people. vitamin d can also act as a hormone; vitamin d2 (ergocalciferol) is derived from the uv-b radiation of ergosterol, the natural vitamin d precursor detected in plants, fungi, and invertebrates. vitamin d3 (cholecalciferol) is synthesized by sunlight exposure from 7-dehydrocholesterol, a precursor of cholesterol that can also act as provitamin d3. dietary intake of vitamin d3 is essential when the skin is exposed for short periods to ultraviolet b light (uv-b), a category of invisible light rays such as uv-a and uv-c. this can be considered the usual situation in northern latitudes during the winter season, or the typical lifestyle for older people and/or for people with very white delicate skin. the actual recommended daily intake of dietary vitamin d is strictly correlated with age, ranging from 5 μg for infants, children, teenagers, and adults—including pregnant and lactating women—to 15 μg for people over 65 years. vitamins are nutrients characterized by low-molecular weight; these compounds are provided by the diet and play a crucial physiological and metabolic role [1] . vitamins are classified into two categories based on liquid solubility [2] : water-soluble vitamins (b complex and vitamin c) and fat-soluble vitamins (a, d, e, and k). most vitamins cannot be synthesized by humans; for this reason, they must be provided by food sources or dietary supplements [3] . vitamins are bioactive nutrients with several health-promoting properties that strongly affect human growth and health [4] . the term 'vitamin d' was coined in 1922, describing a vitamin able to promote calcium deposition [5] . vitamin d in nature is available as ergocalciferol (vitamin d2) or cholecalciferol (vitamin d3) [6] ; vitamin d2 is mainly present in plants or plant products, while vitamin d3 is normally detected in animal source foods [7] . provitamin d3 (7-dehydrocholesterol) is converted to previtamin d3 by the action of ultraviolet radiation on the skin, especially ultraviolet b light characterized by wavelength ranging between 290-315 nm. [8] ; previtamin d3 is converted into 25-hydroxy vitamin d3 (25ohd3), which in turn vitamin d, both provided by food or produced by cutaneous synthesis, undergoes hydroxylation in the liver to 25-hydroxyvitamin d [25(oh)d], which is the most abundant circulating form [16] . later, in the kidney, 25(oh)d is converted into 1,25-dihydroxy vitamin d, which is strictly correlated to calcium and phosphate absorption metabolism in the intestine [17] , also influencing bone cells [18] . parathyroid hormone has a direct effect on the production of 1,25-dihydroxy vitamin d, with specific control of the physiologic reactions necessary to link active vitamin d to calcium homeostasis [19] . the best method to determine in human body vitamin d level is represented by determination of serum concentration of 25(oh)d [20] ; the optimal level for either skeletal or extra-skeletal health is not the same for everybody, but is correlated with the specific population tested. in the human body, ingested vitamin d2 and endogenously produced vitamin d3 are converted to the biologically active form, 1,25-dihydroxyvitamin d [1,25(oh)2d], named calcitriol. in 1969, the nuclear vitamin d receptor (vdr) for 1,25(oh)2d was detected, which has to date been determined in at least 38 human tissues and organs [21] . in fact, vdr was first detected in the bone, kidney, and gastrointestinal tract; and later found in several other tissues, including those in the brain, breast, colon, and prostate [21] . phosphoprotein vdr is involved in different biological functions of calcitriol. because of its widespread distribution, vitamin d is not considered just a calcaemic hormone, and lack of vitamin d is actually associated with several other diseases [22] , such as psoriasis, multiple sclerosis, inflammatory bowel disease, diabetes (both type 1 and 2), hypertension, cardiovascular disease, metabolic syndromes, and different kinds of cancer [21] . severe lack of vitamin d in adults can cause the development of osteomalacia, a disease characterized by the incomplete mineralization of osteoid [23] , while in children, it is responsible for rickets [24] . vitamin d has always been named the "antirachitic factor" [22] . rickets is a disease characterized by decreased mineralization of bone tissue and growth plates, causing weak bones in infants and children [5] . severe vitamin d deficiency (25 ohd < 12.5 nmol/l and levels < 25 nmol/l over a long period) in both infants and children can cause rickets, a disease where bones are deformed [25] . chronic lack of vitamin d dietary intake is the cause of secondary hyperparathyroidism, which is a cause for increased bone turnover, with consequent progressive bone loss and finally an increased risk of bones fracture [26] . several clinical trials have been performed on older patients to evaluate whether vitamin d supplements can decrease the incidence of fractures [27] . the results obtained in clinical trials have shown (see table 3 ) a decrease in fracture incidence in patients receiving vitamin d supplementation [27] . vitamin d supplementation, with or without calcium, can increase bone mineral density (bmd), decrease bone turnover, and decrease fracture incidence [28] . appropriate doses of vitamin d may differ among patients: different genetic polymorphisms, eventual presence of other diseases, and possible use of drugs can affect vitamin d metabolism [29] . osteoporosis is a progressive disease caused by the deterioration of the bone structure because of loss in bone mineral density (bmd) [27] ; its main effect is an increase in the risk of fractures [30] . in the united states, more than 40 million adults over 50 years of age are at a high risk of developing osteoporosis because of low bmd; the total number of patients affected by osteoporosis in the united states is about 12 million [19] . in italy, 3.5 million women and 1 million men are affected by osteoporosis; each year, 250,000 fractures due to osteoporosis are reported, specifically 80,000 hip and 70,000 femur fractures [19] . each year, patients with fracture of the proximal femur show a mortality rate of 15-30% [19] . the occurrence of osteoporosis in african-americans is lower compared to the white population, while small white women, according to epidemiological available data, are the most affected human category [31] . "calcium paradox" is described by the world health organization as the fact that countries with the highest prevalence of osteoporosis are usually those that have a high intake of calcium [32] . bovine milk consumed in these countries contains high levels of both calcium and phosphorus; human milk phosphorus content is about 60% lower [33] . the high phosphorus content in bovine milk is necessary for proper growth of calves; however, in humans, with poor calcium bioavailability, it affects the serum calcium-phosphorus balance, triggering the parathyroid hormone to release calcium from bones. the higher protein content in bovine milk can also negatively affect the calcium balance; the final result is that the high consumption of dairy products, together with other dietary sources of phosphorus, can increase the risk of osteoporosis [32] . low bmd characterizes osteoporosis, with consequent deterioration of the microarchitecture with trabeculae smallness, associated with reduced mineralization, and an increase in cortical porosity [34] . bmd decrease is faster during winter compared to summer [35] . supplementing with vitamin d (800 iu/day) combined with calcium can restrict the fall of bmd during winter [36] . a clinical trial showed a 37% lower risk of osteoporotic fracture in postmenopausal women younger than 65 when their diet was supplemented with vitamin d at a dose of 12.5 µg/day, compared to women receiving less than 3.5 µg/day vitamin d [37] . furthermore, three other clinical trials showed that a combination of calcium and 20 µg vitamin d reduced fracture risk in adults over 65 years [35] . vitamin d status is related to bone mineral density (bmd) not only in vitamin d deficient consumers, but also in vitamin d insufficient subjects [27] . a clinical trial on vitamin d status and bmd in 7441 postmenopausal women with osteoporosis showed a significant positive correlation between serum 25(oh)d and bmd in the trochanteric area of the hip with a threshold below 50 nmol/l [38] . patients with osteoporosis are usually treated with bisphosphonates, calcium, and vitamin d [27] . in italy, 1515 women with postmenopausal osteoporosis treated with bisphosphonates were classified as vitamin d deficient or vitamin d replete; the mean bmd increase per year in the lumbar spine was 0.22% in vitamin d deficient patients versus 2.11% in vitamin d replete patients; similar differences were determined in the hip [39] . these results show that the addition of both vitamin d and calcium in anti-osteoporotic treatment is necessary, unless the patient is vitamin d replete (serum 25(oh)d > 50 nmol/l) and has a dietary calcium intake of 1200 mg/d [28] . the guidelines for the management of postmenopausal osteoporosis describe the importance of satisfying vitamin d requirements in order to obtain the best response for bmd, offering recommendations for its supplementation [31] , together with calcium [40] . diet seems to moderately affect osteoporosis, but calcium and vitamin d intake is very important, at least in older patients. diets low in dairy products have been associated with an increased risk of osteoporosis [41] . a meta-analysis of nine studies reported lower bmd of the spine and hip in vegans compared to consumers who drink milk [42] . more than 8000 studies have been performed to investigate the inverse correlation between vitamin d, its metabolites, and cancer [43] . women with a higher solar uvb exposure in the third national health and nutrition examination survey (nhanes iii) showed 50% incidence of breast cancer compared to those with lower solar exposure [44] . in another survey, men with a higher solar uvb exposure showed only half the incidence rate of fatal prostate cancer [45] . the ultraviolet-b (uvb)-vitamin d-cancer hypothesis was based on a geographical ecological study of colon cancer mortality rates in the united states in correlation to annual sunlight exposure [46] . meta-analyses show significant inverse correlations between serum 25(oh)d concentration and incidence of bladder, breast, colorectal, kidney, and lung cancer [43] . two studies were reported for colon and rectal cancer. in the first one, an inverse correlation was found between 25(oh)d concentration and incidence of distal colon cancer and rectal cancer. in the second study, colon cancer cases were directly correlated with 25(oh)d concentration, while no correlation was determined for rectal cancer [47] . another method to assess vitamin d's role in cancer is to analyze the different cancer survival rates between black and white americans. in the period of 2001-2004, black americans older than 40 y had mean 25(oh)d concentrations between 35 and 43 nmol/l, while white americans had mean concentrations around 63-65 nmo/l [48] . according to these data, black americans would have 60% higher cancer mortality rates than white americans. in the literature, disparities are evident for 13 cancers: bladder, breast, colon, endometrial, lung, ovarian, pancreatic, prostate, rectal, testicular, and vaginal cancer; hodgkin's lymphoma; and melanoma [43] . cancer-specific mortality rates are about 25% higher for black americans compared to white americans. many other health benefits are correlated with higher 25(oh)d concentrations, including reduced risk of autoimmune diseases [49] , diabetes mellitus type 2 [50] , adverse pregnancy and birth outcomes [51] , respiratory tract infections [52] , and celiac disease [53] . recently vitamin d supplementation was tested for its role in preventing coronavirus infections [54] . thus, the increase in 25(oh)d concentrations with the aim of decreasing cancer risk will have other additional benefits [55] . the optimal 25(oh)d concentration is certainly above 75 nmol/l, probably close to 100-150 nmol/l; to obtain those concentrations, 1000-5000 iu/d of vitamin d3 is necessary, or a moderate amount of sun exposure [55] . the only way to surely determine that the desired concentration has been obtained is to evaluate serum 25(oh)d concentration [56] . the uvb-vitamin d-cancer hypothesis has considerable supporting scientific evidence from several experimental studies [55] : geographical ecological, observational, laboratory experiments, as well as many clinical trials. lots of sun exposure and use of vitamin d3 can help prevent and treat many cancers [55] . vitamin d supplementation can reduce the risk of cancer incidence: this thesis should be further investigated in clinical trials in order to determine the right doses of vitamin d and serum 25(oh)d concentrations, and the possible involvement of other safety issues. dairy cow breeding started around 5000 years ago during the late neolithic and early bronze age in northern and central europe [57] . "milk" is normally associated with cow milk; however, milk from other animal species is also consumed [58] . milk is a complete food providing several nutrients, specifically carbohydrates (mainly lactose), proteins, fat, minerals, and vitamins, contributing a mean daily intake of 134 kcal, 8 g of proteins, and 7.3 g of fat to the average human diet [59] . water is the most represented compound in all different milks, ranging from water content lower than 50% in whale milk to water content of around 90% in donkey milk [60] . milk is a natural source of calcium and vitamin d; these nutrients have a synergic interaction in the human body [61] . if the level of ionized calcium in the blood falls, the parathyroid hormone is secreted by the parathyroid gland, stimulating the conversion of vitamin d to its active form, calcitriol (1,25-dihydroxyvitamin d) with a consequent decrease in vitamin d status, determined by measuring the amount of the inactive form. vitamin d, as calcitriol, influences calcium absorption in the intestine, and lack of vitamin d is associated with a reduced absorption of dietary calcium [62] . dietary intake of vitamin d through dairy products, first of all obviously milk, has been investigated in-depth over the last 60 years [1] . in the 1960s, vitamin d content in cow milk was determined to be in the range of 0.125-1 g/l [63] , while a value of 240 iu per liter was detected in cow milk for vitamin d activity, 85% of which is water soluble, attributed to vitamin d3-sulphate [64] . vitamin d content can be described using different units: micrograms (µg) or international units (iu); the most common unit used in europe to describe vitamin d content is µg, while to convert µg to iu, the content in µg must be multiplied by 40 [21] . human milk contains 24,25-dihydroxycholecalciferol and 1,25-dihydroxy vitamin d3; vitamin d content in human milk is considered very low [64] . a study on 198 children, followed up to 9 years of age, evaluated the effect of maternal vitamin d status during pregnancy on childhood skeletal growth [15] . results obtained in 9-year-old children fed by mothers who had vitamin d insufficiency (25 ohd levels < 40 nmol/l, 31%, n = 49) or vitamin d deficiency (25 ohd levels < 25 nmol/l, 18%, n = 28) during late pregnancy showed lower whole body and lumbar spine bone mineral content (bmc). according to the results of this study, vitamin d supplementation is recommended in pregnant women, especially in the winter months, when sunlight is less. the most important result obtained is the long-lasting positive effect on peak bone mass (pbm) attainment, together with a reduced risk of osteoporotic fracture in older patients [65] . a recent study [66] determined total vitamin d content in donkey milk (23 mg/l, about 920 iu/l); it was found to be higher compared to the values obtained by analyzing milk produced by several mammalian species, including human milk [67] . even if donkey milk represents a niche product, its use is recommended for consumers at risk of nutritional deficiencies, such as children and/or elderly; in these patients, donkey milk could help prevent lack of vitamin d [58] . milk consumption has decreased in recent years, and dietary intake of vitamin d by way of fresh milk has declined [68] , while cheese consumption has significantly increased (by almost 100%) since 1980 [68] . the big increase in human population and change in food consumption habits has created the right conditions for production of new fortified foods able to provide the recommended intake of vitamin d in the human diet. milk does not provide the dietary requirements of vitamin d (table 4) , while cheese represents the right kind of food for the recommended dietary intake of this nutrient; in the states, the fortification level of vitamin d in cheese is strictly regulated by the u.s. food and drug administration [69] . in patients with osteoporosis, treatment with drugs is the best approach to decreasing the risk of other fractures. however, even in these patients, the importance of nutrition should be taken into consideration, because inadequate intake of ca, vitamin d, and proteins may reduce the efficacy of anti-osteoporotic drugs [69] . in one study, 37 elderly women with vitamin d deficiency received fortified soft plain cheese [69] ; the dairy product provided 17-25% of the recommended dose of vitamin d (10-15 mg) and 25% for both ca (1200 mg) and proteins (1 g/kg body weight). with daily consumption of two servings of soft plain cheese for one month, the vitamin d supplement caused a small increase in serum 25(oh)d. the results obtained in this clinical trial demonstrated that fortified soft plain cheese consumed by elderly women with vitamin d deficiency can reduce bone resorption, positively affecting ca and protein metabolism, analyzing the decrease in pth and increase in igf-i, respectively [69] . vitamin d deficiency is a public health issue that affects both men and women, causing huge human and financial costs [70] . consumers can improve and maintain vitamin d status through increased consumption of natural or fortified food sources or vitamin d-containing dietary supplements [71] . there are only few foods naturally rich in vitamin d, and most of these show great seasonal variation in vitamin d content [72] . frequent fish consumption can be a good strategy to maintain the required levels of 25(oh)d, as determined in elderly japanese women [73] . frequent fish eaters can maintain required serum 25(oh)d levels also during winter. mushrooms represent another food that is a natural source of vitamin d; all edible mushrooms are rich of ergosterol, which, when irradiated with sunlight or uvb light, is transformed into vitamin d2 [74] . fortification of common foods represents an easy and practical method to avoid micronutrient deficiency [75] . the first fortified food was created around 4000 years bc by the persian physician melampus, who enriched wine with iron filings to increase sailors' resistance and their sexual activity [76] . around six thousand years later, in 1833, the chemist boussingault in france added iodine to salt to prevent goiter. in the 1920s, in denmark, vitamin a was used to enrich margarine, while in the 1930s dairy companies in the united states began to enrich milk with vitamin d to prevent rickets in children [77] . in canada, vitamin d fortification is compulsory for milk and margarine, while vitamin d addition to food in the u.s. is optional, with the exception of fortified milk [78] . milk is the main fortified food in the u.s. and in canada [72] , but the amount of vitamin d added to milk (1 mg/100 g fluid milk) is not adequate to produce the desired increase or maintain circulating 25(oh)d. vitamin d fortification at higher levels (10 mg/50 g powdered milk) showed significant effects in improving vitamin d status and bone mineralization in older women milk [79] . milk products are systematically, either mandatorily or voluntarily, fortified with vitamin d only in finland, norway, sweden, canada, and the united states [80] . in finland, the actual recommended fortification level of all fluid milks, with the exception of some organic products, is 1 µg/100 g, but there are also some kinds of milk marketed with a concentration of 2 µg/100 g [80] . the fortification is not compulsory, but all dairy companies are actually following these recommendations. in norway, only one type of milk is recommended to be fortified with vitamin d at a concentration of 0.4 µg/100 g [80] . sweden recently doubled the fortification levels of fluid milks to 1 µg/100 g and imposed a compulsory fortification for all fluid milks with less than 3% of fat [9, 10] . in other countries, such as united kingdom, ireland, spain, and australia, fortification is not mandatory, but there are several vitamin d-fortified milk products available [81] . in countries where vitamin d fortification policies are strongly applied (finland, canada, united states), the contribution of milk to total vitamin d intake is higher compared to countries without wide fortification policies, such as ireland, united kingdom, spain, and australia [80] . the consumption of vitamin d-fortified milk was positively associated with 25(oh)d status [80] , without a specific effect of local vitamin d-fortification policies. even when the total amount of milk consumption was quite different, the correlation among milk consumption and 25(oh)d status was determined at relatively low consumption levels [82] . vitamin d fortification of foodstuff has been shown to be a valid way to increase vitamin d dietary intake; and vitamin d-fortified fluid milk affect both vitamin d intake and 25(oh)d status [83] . however, fortification of fluid milks may not be the only strategy. specific staple foods should be chosen in each different country as the best vitamin d carriers considering the results of simulation studies. in many countries where a fortification policy is not currently applied (see table 5 ), the hypothesis of systematic vitamin d foods fortification has been considered, and simulation studies have been recently performed [84] . the optimal vitamin d status has not been determined yet; the endocrine society's clinical practice guidelines established a lower serum threshold for 25(oh)d level as 75 nm or 30 ng/ml [85] . the institute of medicine (iom) determined these thresholds for s-25(oh)d status: <30 nmol/l is vitamin d deficient, 30-49.9 nmol/l is insufficient, and >50 nmol/l is sufficient [86] . vitamin d3, administered through cod liver oil, has been used in infant nutrition in northern europe since the 1700s-at a daily dosage of a small teaspoon [87] . this experimental dose of cod liver oil was really effective, as discovered in studies performed two centuries later [88] ; the 375 iu (9 µg) of vitamin d3 in one teaspoon was confirmed as being the most appropriate for children [89] . vitamin d intake has been better characterized in children nutrition compared to adult requirements [90] . in the 1960s, a scientific committee determined the requirement for vitamin d in adults and recommended one-half of that was infants [87] . strategies to improve vitamin d status in the population are based on an increased intake of naturally vitamin d containing foods, production of fortified foods, using vitamin d supplements, increasing solar uv-b exposure, and weight loss [91] . vitamin d food fortification seems to be the best strategy to improve vitamin d intake and status in human population in order to meet dietary vitamin d recommendations [92] . considering the lack of natural vitamin d-rich foods, some countries, particularly populations at high latitudes, developed national policies of fortifying certain foods with vitamin d to prevent deficiency of this nutrient [93] . the most common vitamin d-fortified foods are low-fat milk, fat spreads, breakfast cereals, and certain baby foods [83] . considering the different food habits among different populations, wider vitamin d fortification of several products rather than concentrating on the limited production of a small amount of staple foods has been suggested [83] . in general, food can be enriched with vitamin d by simply adding vitamin d to it (i.e., traditional vitamin d food fortification) or practising the so called "bioaddition" [94] . bioaddition of vitamin d, which has also been called "biofortification," refers to different methods of increasing vitamin d content in food without direct exogenous addition of this compound [94] . milk fortification with vitamin d started in the usa in the 1930s [70] . milk was initially fortified using two different methods: by irradiating milk with vitamin d or feeding the cows irradiated yeast [70] . in the 1940s, a simple and valid method based on direct supplementation of vitamin d concentrate to milk was developed; it is still in use today [70] . in the united states, several rte (ready-to-eat) breakfast cereals are fortified with vitamin d and also added to yogurt and margarines, while in canada, it is not permitted to fortify rte breakfast cereals. however, in fortified foods, the level of vitamin d must not exceed 20 iu/100 calories [95] . the efficacy of vitamin d food fortification in increasing vitamin d serum level has been tested [70] . foods fortified with vitamin d normally contain 100 iu per serving; consumption of fortified milk increased vitamin d intake and was responsible for a significant increase of 25(oh)d levels [21] . an average daily intake of about 11 µg (440 iu/day) using fortified foods (range 120-1000 iu/day) achieved 25(oh)d concentrations up to 7.7 ng/ml. a daily increase of 0.5 ng/ml in 25(oh)d levels was achieved for each 40 iu (1 µg) ingested [70] . the most common food fortified with vitamin d is fresh milk, contributing 44% of the total daily vitamin d intake. male teenagers (13 to 18 years) [82] had the highest vitamin d intake among the age/sex categories; however, on evaluating the other consumers involved in the study, dietary intake of 400 iu was not sufficient to reach serum levels of 16 ng/ml [96] . therefore, considering that the vitamin d dietary requirement can be satisfied when in serum vitamin d level is ≥30 ng/ml, actual consumers mean intake of vitamin d can be considered low and not adequate, compared to daily nutritional requirements [97] . higher levels of vitamin d fortification are required in order to increase the number of consumers with serum levels of 25(oh)d ≥ 20 ng/ml [98] . vitamin d fortification strategies have also been evaluated in consumers living in developing countries, adding both vitamin d and vitamin a to fresh milk, cheese, and margarine; however, the results obtained in these trials have not been clearly discussed [99] . when considering vitamin d food fortification, it is important to evaluate whether such a public health intervention is likely to be cost-effective [100] . usually, micronutrient fortification is considered the most cost-effective public health intervention [101] . with reference to vitamin d food fortification, there are only a few reports available on its cost-effectiveness. the available studies have reported that systematic vitamin d fortification may indeed be highly cost-effective [102] . the following distribution of costs for a typical food fortification programme was determined as follows: 80% recurrent production costs, 8% marketing and education costs, 7% food control and monitoring costs, and 5% other production costs [103] . the deposition of bone minerals begins during pregnancy, particularly in the last three months; bone mass can increase about 40 times from birth to adulthood, with a peak close to 90% occurring around the age ranging between 18 and 20 years [15] . in fact, the most critical periods for bone minerals deposition are represented by childhood and adolescence [104] . bone is a living tissue continuously subjected to cycles of bone formation and bone resorption: poor skeletal integrity causes an increased risk of osteoporotic fractures [105] . clinical trials have shown that mild vitamin d insufficiency can have a negative effect on bone mineral mass in adolescent females [106] and children [107] . the effect of vitamin d supplementation (200 iu/day or 400 iu/day) on bone mineral deposition has been examined in 212 adolescent girls (mean age 11.4 years) who were receiving ca supplementation as well [108] . the results showed that bone mineral augmentation of the femur was 14.3% and 17.2% higher, respectively, in groups receiving vitamin d supplementations compared to a placebo. furthermore, vitamin d supplementation significantly reduced bone resorption, evaluated by determining urinary deoxy-pyridinoline excretion [108] in postmenopausal women, several studies based on vitamin d and calcium supplementation have been conducted in order to determine the best nutritional strategies [109] . a pooled analysis, describing the effect of vitamin d supplementation on fracture reduction, showed that there was a significant reduction in the incidence of hip fractures when doses higher than 792 iu/day were administered [110] . however, there was no significant decrease in hip fracture risk caused by calcium intake [111] . circulating 25(oh)d is generally considered the most reliable marker of vitamin d status [70] . the serum content of 25(oh)d necessary to maintain adequate levels of pth is considered to be between 30 and 100 nmol/l [112] . because of this high variability, vitamin d insufficiency within populations can be differently evaluated depending on the threshold used. in a study performed using 8532 postmenopausal, osteoporotic european women, 79.6% were considered to found to have inadequate levels of vitamin d if the serum 25(oh)d threshold was fixed to the value of 80 nmol/l, while when the threshold was reduced to 50 nmol/l, women with severe lack of vitamin d were a smaller amount, 32.1% [113] . based on the results obtained in several clinical trials, 80 nmol/l is considered to be an overestimated threshold, while 50 nmol/l is believed to be an acceptable threshold [109] . the dose used for vitamin d supplementation should be enough to reach the threshold values of serum 25(oh)d, otherwise the expected target will not be obtained. clinical trials performed with the aim of determining the anti-fracture efficacy of different doses of vitamin d found that 400 iu per day was not enough to achieve a significant effect in reducing fracture rate [114] . oral daily doses of 700-800 iu or a dose of 100,000 iu taken quarterly both showed a positive anti-fracture effect, while an annual intramuscular dose of 300,000 iu did not show valid efficacy [114] . the results obtained in these studies show that the most effective vitamin d supplementation in osteoporotic patients is obtained when administered orally either daily or quarterly; in case of a daily supplementation, the dose should be higher than 700-800 iu/day [114] . however, it is important to consider that, according to several clinical trials performed all over the world, the most effective anti-osteoporotic results were achieved with combined treatment with calcium and vitamin d supplementation [115] . in women over 65 years of age, the risk of osteoporotic fracture can be frequent, particularly if a lack of calcium is associated with vitamin d deficiency [70] . in these cases, calcium and vitamin d supplementation can be useful, administering doses of 1000-1200 mg of calcium and 800 iu of vitamin d daily, respectively [116] . the recommended strategy is to combine vitamin d and calcium into a unique supplement in order to increase a patient's healthy status, with a consequent improvement in treatment efficacy. the risk of osteoporotic fracture is increased with vitamin d deficiency [117] . in fact, biologically active vitamin d enhances calcium intestinal absorption by regulating calcium transport proteins in the small intestine, stimulating osteoclastic maturation and helping bone growth [53] . vitamin d supplementation is required in order to reach 25(oh)d concentrations above 30 ng/ml in a large number of people. vitamin d fortification of basic foods such as dairy and flour products can increase serum 25(oh)d concentrations, reducing the risk of osteoporosis. prevention is absolutely necessary, considering that in 2030, 25% of the human population will be over 65 years of age. using appropriate feeding strategies in dairy cows, natural vitamin d content in dairy products, especially fresh milk, can be increased; further studies are necessary to optimize the total natural vitamin d content in dairy products, considering that in several countries, fortification of food is not always permitted as a common practice. author contributions: conceptualization, v.p. and p.p.; writing-original draft preparation, 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micronutrient intervention cost literature: program design and policy lessons the projected public health and economic impact of vitamin d fortified dairy products for fracture prevention in france economic evaluation of vitamin d and calcium food fortification for fracture prevention in germany vitamin d and neurological diseases: an endocrine view epidemiology and public health impact of osteoporosis vitamin d status affects serum parathyroid hormone concentrations during winter in female adolescents: associations with forearm bone mineral density association of low 25-hydroxvitamin d concentrations with elevated parathyroid hormone concentrations and low cortical bone density in early pubertal and prepubertal finnish girls a positive dose-response effect of vitamin d supplementation on site-specific bone mineral augmentation in adolescent girls: a double-blinded randomized placebo-controlled 1-year intervention combined calcium and vitamin d3 supplementation in elderly women: confirmation of reversal of secondary hyperparathyroidism and hip fracture risk: the decalyos ii study a pooled analysis of vitamin d dose requirements for fracture prevention randomized trial of physical activity and calcium supplementation on bone mineral content in 3-to 5-year-old children estimates of optimal vitamin d status fracture prevention with vitamin d supplementation how to select the doses of vitamin d supplementation in the management of osteoporosis the relationship between vitamin d and parathyroid hormone: calcium homeostasis, bone turnover, and bone mineral density in postmenopausal women with established osteoporosis estimation of total usual calcium and vitamin d intakes in the united states reducing fracture risk with calcium and vitamin d funding: this research received no external funding. the authors declare no conflict of interest. key: cord-005428-pm7ihh9t authors: amrein, karin; scherkl, mario; hoffmann, magdalena; neuwersch-sommeregger, stefan; köstenberger, markus; tmava berisha, adelina; martucci, gennaro; pilz, stefan; malle, oliver title: vitamin d deficiency 2.0: an update on the current status worldwide date: 2020-01-20 journal: eur j clin nutr doi: 10.1038/s41430-020-0558-y sha: doc_id: 5428 cord_uid: pm7ihh9t vitamin d testing and the use of vitamin d supplements have increased substantially in recent years. currently, the role of vitamin d supplementation, and the optimal vitamin d dose and status, is a subject of debate, because large interventional studies have been unable to show a clear benefit (in mostly vitamin d replete populations). this may be attributed to limitations in trial design, as most studies did not meet the basic requirements of a nutrient intervention study, including vitamin d-replete populations, too small sample sizes, and inconsistent intervention methods regarding dose and metabolites. vitamin d deficiency (serum 25-hydroxyvitamin d [25(oh)d] < 50 nmol/l or 20 ng/ml) is associated with unfavorable skeletal outcomes, including fractures and bone loss. a 25(oh)d level of >50 nmol/l or 20 ng/ml is, therefore, the primary treatment goal, although some data suggest a benefit for a higher threshold. severe vitamin d deficiency with a 25(oh)d concentration below <30 nmol/l (or 12 ng/ml) dramatically increases the risk of excess mortality, infections, and many other diseases, and should be avoided whenever possible. the data on a benefit for mortality and prevention of infections, at least in severely deficient individuals, appear convincing. vitamin d is clearly not a panacea, and is most likely efficient only in deficiency. given its rare side effects and its relatively wide safety margin, it may be an important, inexpensive, and safe adjuvant therapy for many diseases, but future large and well-designed studies should evaluate this further. a worldwide public health intervention that includes vitamin d supplementation in certain risk groups, and systematic vitamin d food fortification to avoid severe vitamin d deficiency, would appear to be important. in this narrative review, the current international literature on vitamin d deficiency, its relevance, and therapeutic options is discussed. vitamin d testing has exponentially increased in recent years [1] . the definition and relevance of vitamin d deficiency are still under debate. recent large observational data have suggested that~40% of europeans are vitamin d deficient, and 13% are severely deficient [2] . the relevance of this widespread deficiency and necessity for supplementation has been questioned [3] . certainly, vitamin d is not a panacea. because more often than not, trials have included non-deficient individuals, it is not surprising that interventional trials have usually not been able to find a benefit of vitamin d supplementation on clinical outcomes. this was also reflected in meta-analyses on the topic that were carried out with poor methodological standards [4] . consequently, many authors have dismissed a role of vitamin d on important clinical outcomes, and suggested that vitamin d may be more an associative than a causal factor in acute and chronic disease. on the other hand, a low vitamin d status is emerging as a very common condition worldwide, and several studies from basic science to clinical applications have highlighted a strong association with chronic diseases, as well as acute conditions. moreover, the large amount of observational data currently available are also accompanied by pathophysiological associations of vitamin d with energy homeostasis, and regulation of the immune and endocrine systems [5] . recent negative interventional trials may be biased by substantial methodological and study design errors, making it impossible to show the potential contributing role of vitamin d supplementation in a deficient population. typically, most studies have missed important prerequisites for a nutrient intervention trial: the absence of the problem to be solved-vitamin d deficiency, often ridiculously small sample sizes, and varying interventional regimes regarding dose and metabolite. even the recent very large trials did not exclusively include deficient populations [6] [7] [8] . moreover, interventional regimes have used a onesize-fits-all approach without taking into account individual differences in bmi and vitamin d metabolism. articles were individually retrieved up to october 2019 by search in pubmed (medline). studies were excluded if they were not in english. across the last few decades, vitamin d-related research/publications have dramatically increased. therefore, we decided to focus on the largest, most relevant, and most recent studies that are now in this version of the review. all authors supplied a first draft paper on a specific topic. all papers were then exchanged and discussed among authors by e-mail. serum 25(oh)d is considered to be the best marker for assessing vitamin d status, and reliably reflects the free fractions of the vitamin d metabolites, despite the fact that, in theory, the bioavailable fractions may be more clinically informative [9, 10] . a range of below 75 nmol/l (or 30 ng/ml) of serum/plasma 25(oh)d concentration is considered vitamin d deficiency by most authors [11, 12] . a cutoff of <25 or <30 nmol/l (or 10/12 ng/ml) increases the risk of osteomalacia and nutritional rickets dramatically, and therefore is considered to determine severe vitamin d deficiency [13] [14] [15] [16] . the clinical practice guidelines of the endocrine society task force on vitamin d [12] have defined a cutoff level of 50 nmol/l as vitamin d deficient. furthermore, different societies and expert bodies have defined 50 nmol/l as "vitamin d requirement of nearly all normal healthy persons," by using bone health as the main basis. for example, a cutoff level of 50 nmol/l is recommended by the institute of medicine (iom, usa) in their "dietary reference intakes". vitamin d levels of <30 nmol/ l (or 12 ng/ml) should likely be prevented with a public health approach [17] . there are many large and relevant risk groups for vitamin d deficiency ( table 1) . prevalence rates of severe vitamin d deficiency, defined as 25(oh)d <30 nmol/l (or 12 ng/ml), of 5.9% (us) [18] , 7.4% (canada) [19] , and 13% (europe) [2] have been reported. estimates of the prevalence of 25(oh)d levels <50 nmol/l (or 20 ng/ml) have been reported as 24% (us), 37% (canada), and 40% (europe) [2, [17] [18] [19] . this may vary by age, with lower levels in childhood and the elderly [17] , and also ethnicity in different regions, for example, european caucasians show lower rates of vitamin d deficiency compared with nonwhite individuals [2, 17] . worldwide, many countries report very high prevalences of low vitamin d status. 25(oh)d levels <30 nmol/l (or 12 ng/ml) in >20% of the population are common in india, tunisia, pakistan, and afghanistan. for example, it has been estimated that 490 million individuals are vitamin d deficient in india [2, 17] . specific categories of patients have a very high prevalence of vitamin d deficiency. often, they are characterized by an insufficiency or failure of organs involved in vitamin d metabolism. patients with chronic renal failure and on hemodialysis, renal transplant recipients affected with liver disease or after liver transplantation may have a prevalence of vitamin d deficiency ranging from 85 to 99% [20] [21] [22] . similarly, critically ill patients have a very high prevalence of vitamin d deficiency, and low vitamin d levels are clearly associated with greater illness severity, morbidity, and mortality in both adult and pediatric intensive care unit (icu) patients, as well as medical and surgical icus [23] . however, as in most other populations, the most important question remains unanswered: whether low vitamin d is an innocent bystander, simply reflecting greater disease severity, or represents an independent and modifiable risk factor amenable to rapid normalization through loading dose supplementation [24, 25] . the question is meaningful, since in this subgroup of patients, many factors contribute to low levels: hemodilution, reduced production and conversion by the liver, reduced synthesis of vitamin d-binding protein, higher consumption during the acute phase of disease and systemic inflammation, and increased tissue demand and enhanced catabolism of metabolites. more data are emerging from basic science about the immediate and late effects of vitamin d supplementation on endocrine, autocrine, and paracrine and genomic targets. metabolites it cannot be emphasized enough that various vitamin d metabolites with a very different efficacy, half-life, and risk of toxicity exist. this is discussed in detail in "vitamin d supplementation: cholecalciferol, calcifediol and calcitriol" by reinold vieth et al. in this special issue. for some time, bolus dosing was en vogue because it was thought to be interesting for practical reasons. with the exception of critical care, bolus doses with long dosing intervals are not used. they are no longer recommended because of the higher risk of adverse effects (falls and fractures) associated with them [26] . moreover, the 2017 individual patient data meta-analysis by martineau et al. showed a clear benefit for vitamin d on acute respiratory infection when daily or weekly dosing was used, but not with longer dosing intervals [16] . in the intensive care, however, a typical daily dose is inefficient, and an upfront loading dose (followed by a daily dose) is necessary to improve vitamin d levels rapidly [27] . it is also important to note that different dosing regimes may have different effects on clinical outcomes. because a daily dose leads to stable availability of various vitamin d metabolites, this could be an important explanation for many of the negative vitamin d intervention trials [28] . to maintain optimal vitamin d status, use of vitamin d supplementation is often required, as sunlight exposure and dietary intake alone is usually insufficient in most individuals [29] [30] [31] . currently, there is no international consensus on the optimal level for vitamin d supplementation. recommendations differ in many countries, and range from 400 to 2000 iu daily [11] . a safe and commonly available dose of 25 μg of vitamin d3 (1000 iu) raises 25hydroxyvitamin d [25(oh)d] serum level by 15-25 nmol/ l on average (over weeks/months) [32, 33] ; it should be noted that there is a nonlinear response of serum 25(oh)d, with a steeper rise with <1 iu/day of vitamin d, and a more flattened response with >1 iu/day. this is evidenced by several studies in all age groups [11, 34] . by using the above-mentioned recommended vitamin d supplementation levels, there is no need to monitor serum or urinary calcium or renal function [35, 36] . there is no international consensus on the safe upper level for vitamin d supplementation. while the upper daily limit given by the endocrine society is 10,000 iu [12] , the iom and the european food and safety authority recommend staying below 4000 iu/day (100 µg) [37, 38] . most countries have prudently set the safe upper level at 50 μg daily (2000 iu) for adults [35] . however, this level was set despite the availability of adequate studies of dose-response relationships or toxicity. there is no convincing evidence that daily intakes of up to 125 μg (5000 iu) elicit severe adverse effects [39] . it has been reported that an intake of 1250 µg (50,000 iu) once every 2 weeks for several years, equivalent to 89.3 µg (3571 iu) daily, did not cause hypercalcemia or other evidence of hypervitaminosis d [40] . small studies showed that even a daily consumption of up to 250 μg (10,000 iu) of vitamin d over long periods did not cause adverse effects in healthy adults [32, 33] , though some studies revealed a negative impact on bone mineral density by using high-dose vitamin d supplementation of 10,000 iu/day [11] . nevertheless, supplementation of >10,000 iu of vitamin d is rarely necessary in clinical practice. as there is no evidence that increasing the recommended daily dose of vitamin d supplementation up to 50 μg (2000 iu) would cause severe side effects in the general population, and considering that 20 μg (800 iu) is the lowest dose consistently associated with a bone benefit, it seems reasonable to recommend a daily dose of 20-50 μg (800-2000 iu) (levels 2-4 evidence, grades b-d recommendation) [39] . in general, a daily vitamin d of 800 iu appears to be sufficient to achieve a target 25(oh)d level of at least 50 nmol/l (or 20 ng/ml) in most healthy individuals, whereas 2000 iu is sufficient to achieve a level of at least 75 nmol/l (or 30 ng/ml). some data suggest that a higher 25(oh)d level than 50 nmol/l (or 20 ng/ml) may be required for optimal risk reduction for various endpoints [41] [42] [43] [44] . the use of vitamin d supplementation has increased substantially. growing awareness of vitamin d in the general population, and over-the-counter vitamin d with partially very high doses, include the risk for uncontrolled use and exogenous hypervitaminosis d, resulting in high concentrations of serum 25(oh)d or free 1,25-dihydroxyvitamin d [1,25(oh) 2 d], leading to hypercalciuria and finally hypercalcemia [45] . reports of vitamin d overdose are rare in the literature. serum 25(oh)d usually exceeds 375 nmol/l (or 150 ng/ml), and factors such as high-calcium intake contribute to the risk of hypercalcemia [46] . however, there are also endogenous causes of hypervitaminosis d, such as increased production of 1,25(oh) 2 d as part of granulomatous disorders or lymphomas [47] . having a long half-life in the tissues, vitamin d accumulation due to excessive intake lasts up to 18 months [48] , and may cause chronic toxic effects such as nephrocalcinosis following hypercalcemia and hypercalciuria [47] . since the 1930s, public health officials in the united states and the united kingdom have recommended routine fortification of foods like milk to prevent vitamin d deficiency and low vitamin d status, which was expected to be an effective public health strategy [46] . however, there was an increased incidence of hypercalcemia due to massive intakes of vitamin d from various food fortifications. in some cases, hypercalcemia was associated with drinking vitamin d-fortified milk, revealing a fortification of up to 232,565 iu instead of standard 400 iu/quart, and consequently, prohibition of milk fortification [49] . however, current evidence suggests that vitamin d fortification prevents deficiency safely and effectively [50, 51] . feeding animals might represent an additional source of vitamin d without compromising product quality. for example, consumption of vitamin d-enriched eggs from hens fed with additional vitamin d3 resulted in a zero prevalence <25 nmol/l, while the control group showed an usual seasonal decline in winter with 22% being <25 nmol/l [52] . the rationale and guidance for systematic vitamin d food fortification, including a call for action, has recently been published by an expert group of vitamin d scientists. several very large randomized controlled trials have been or are being performed in recent years. they are summarized in table 2 [53] [54] [55] [56] [57] [58] [59] [60] [61] [62] [63] . though it appears attractive to dismiss any relevant effect of vitamin d on all the conditions that have been studied in those partly very large trials in recent years, it must be considered that often the basic principles for optimal design of a nutrient intervention study were not fulfilled [64] , e.g., measurement of vitamin d at baseline and choosing vitamin d deficiency as an inclusion criterion, using a meaningful intervention able to change vitamin d status, and verification of vitamin d status improvement by repeat measurement. moreover, even in the largest trials including thousands of individuals, the sample size was still too small when mostly individuals without vitamin d deficiency and a low baseline risk were included. by modeling future intervention trials, brenner et al. reported that several hundreds of thousands of participants would be necessary to be able to show an effect on mortality [65] . on the other hand, even a very small effect may be useful for a substance with such an excellent safety profile and low cost, especially when considering a public health approach. however, to show a small, but meaningful benefit on important outcomes like mortality or infections, very large population samples are needed, but such trials are very costly and will likely be scant. the association of vitamin d supplementation on a number of endpoints including mortality has been explored in more detail in the last few years. selected relevant systematic reviews and meta-analyses are summarized in table 3 [16, 66, 67]. vitamin d deficiency 2.0: an update on the current status worldwide mortality vitamin d deficiency has been strongly associated with various health outcomes, including all-cause mortality [68] . a 2014 cochrane meta-analysis showed a relevant and significant lower all-cause mortality of~7% and cancer mortality of~13% in patients who received vitamin d3 [69] . the results of a meta-analysis by using individual participant data conducted by gaksch et al., analyzing almost 17,000 individuals, showed a strong association between low 25(oh)d and increased risk of all-cause mortality [70] . using a mendelian randomization with genetic variants in the vitamin d synthesis pathway, the analysis of aspelund et al. supports a causal relationship between vitamin d deficiency and increased all-cause mortality. however, despite a cohort of >10,000 participants, it was still too underpowered to confirm a causal relationship [71] . the effect of vitamin d on the lungs has a strong rationale, demonstrated by basic science, due to its immunomodulant, anti-inflammatory, and anti-infective role that has been highlighted in patients with community-acquired infections, acute respiratory failure, as well as in lung transplantation recipients (this is a very specific model for severe infective and inflammatory lung disease) [21] . vitamin d supplementation reveals direct antiinflammatory properties in the lungs. this is due to local inhibition of nuclear factor-κb and mitogen-activated protein kinase activity, reducing the secretion of inflammatory cytokines and chemokines involved in the lung inflammatory process and extravascular leaking, such as interleukin (il)-1β, il-6, and il-8. this, in turn, also influences the number of inflammatory cells infiltrating the interstitial space [72] . moreover, 1,25(oh) 2 d is also implicated in the reduction of oxidative stress by inhibiting anti-protease activity, and acting on the nuclear factor erythroid-related factor 2, a transcriptional regulator of most antioxidant genes. moreover, vitamin d acts with well-known antiinfectious properties by increasing proliferation of monocytes to macrophages (acting as a fine-tuner of the innate and adaptive immunity), and determining a transcriptional upregulation of cathelicidin also in the airway epithelial cells. finally, 1,25(oh) 2 d inhibits the expression of several metalloproteinases in airway smooth-muscle cells and alveolar macrophages, thus being involved in the tissue remodeling pathway by regulating the process of bronchial airway muscle activation and extracellular matrix deposition by fibroblasts. all these complex pathways, partially modified by vitamin d, warrant supplementation in patients with respiratory disease. significant benefits have already been shown in adults and children with asthma, and for the prevention of respiratory tract infections, particularly in severe vitamin d deficiency. sepsis, a complication of severe infection, is characterized by signs of systemic inflammation expressed with failure of organs often remote from the site of the initial infection. septic patients have high mortality and lower circulating levels of vitamin d. the interest in vitamin d for infection has risen after the recognition of the expression of the vitamin d receptor, ubiquitous in cells of the innate and adaptive immune system. vitamin d is an important link between toll-like receptor activation and antibacterial responses. the in vivo supplementation of a high dose of cholecalciferol (400.000 iu as a single bolus) in the early stage of sepsis and septic shock has been shown able to safely and rapidly increase the level of vitamin d, as well as the circulating level of cathelicidin, a vitamin d-dependent endogenous anti-microbial and endotoxin-binding peptide largely found in human neutrophils [73] . these findings were corroborated by the significant reduction of il-1β and il-6, which play important roles in the early inflammatory response. several studies have highlighted that lower 25(oh)d levels are associated with prolonged hospitalization and mortality, also in the postsurgical setting. given its wide immunobiological effects, vitamin d has been frequently considered a potential modulating factor after solid organ (and stem cell) transplantation (mainly liver, kidney, and lung). the transplantation recipient population is particularly prone to infections, mainly in the early stage after transplantation, due to immunomodulation/chronic immunosuppressive therapy and to long-term bone dysfunction. the recipients of solid organ transplantation are, by definition, vitamin d insufficient for manifold reasons, including limited sunlight exposure, limited physical activity, reduced dietary intake of vitamin d in food, as well as liver and kidney dysfunction according to their main disease. as an example, in liver transplantation recipients (a group of patients with very low vitamin d levels), osteoporosis has a high prevalence, with a large decline in bone mineral density in the first year after transplantation. moreover, a negative association between low vitamin d levels and graft function, as well as a role of vitamin d in reducing the recurrence of hepatitis c virus infection, has been demonstrated. several interventional trials on vitamin d supplementation in lung and kidney recipients are ongoing under the hypothesis that vitamin d supplementation may contribute to reducing the occurrence of rejection by it immunomodulating action. in 2019, two cochrane analyses on vitamin d and pregnancy were published. they suggested that vitamin d supplementation may reduce gestational diabetes, low birthweight, and preeclampsia, but a higher than currently recommended dose appeared to have no additional benefit except for possible further reduction of gestational diabetes [74, 75] . however, several studies in recent years have highlighted that women are at high risk for vitamin d deficiency, and this is associated with adverse pregnancy outcomes, including preeclampsia and gestational diabetes [76] [77] [78] [79] [80] . it has been demonstrated that vitamin d supplementation is able to reduce adverse pregnancy outcomes when a higher level is achieved, with an increasing efficacy when the target level is raised from 20 to 40 ng/ml or 50 ng/ml. interestingly, the maximum change is achieved 6-8 weeks after initiating the treatment, likely exerting the genomic actions of vitamin d [81] [82] [83] . three major adverse pregnancy outcomes appear to improve with vitamin d supplementation: a 60% reduction in preeclampsia, a 50% reduction in gestational diabetes, and a 40% reduction in preterm delivery [84] . these data are consistent with previous work on the topic [82] . moreover, following the genomic and epigenetic effects of vitamin d supplementation, vitamin d deficiency during pregnancy also seems able to induce specific genomic pathways relevant to autoimmune disease in childhood and later in life [85, 86] . the placenta can convert 25(oh)d to the active form 1,25(oh) 2 d, similarly to the kidneys; therefore, more basic research should shed light in the future on the specific vitamin d metabolism during pregnancy [85] . the fda has recently approved the statement "pregnant women who have higher serum vitamin d levels have a decreased risk of preterm birth." taking into account the recent literature, vitamin d deficiency is associated with worse outcomes during pregnancy, and at least 400-600 iu of daily vitamin d supplementation is reasonable for women with a vitamin d level <40 ng/ml, with higher required doses in more severe deficiency. vitamin d supplementation as a strategy for preventing cancer was considered, as results from several observational studies suggested an association between vitamin d deficiency and risk for several types of cancer [87] . it was already assumed in 1980 that calcitriol could inhibit the growth of malignant melanoma cells [88] . ecologic studies revealed a decreased cancer mortality in areas with greater sun exposure [11] . over the decades, vitamin d and its anticancer action was investigated for various malignancies resulting in mixed findings [89] . hence, the cancerprotective effect of vitamin d remained unclear. in 2014, two meta-analyses revealed no significant decrease in the incidence of cancer in association with vitamin d supplementation, but a significant reduction in the rate of death from cancer [90, 91] . however, as most of the data derive from observational studies, correlation does not imply causation. investigating cancer incidence following vitamin d plus calcium supplementation, lappe et al. revealed a non-, but nearly significant (hazard ratio 0.70; 95% ci 0.47-1.02) 30% risk reduction compared with placebo [92] . a recent large rct using a daily dose of 2000 iu vitamin d3 conducted by manson et al. [7] , analyzing the incidence of cancer following vitamin d supplementation in over 25,000 participants, did not reveal a significant reduction neither of invasive cancer of any type nor in the rate of death from any cause. however, subgroup analyses revealed a significant lower cancer incidence in normalweight individuals. considering that the study was not adjusted for this comparison, this finding should be considered hypothesis-generating. an ongoing long-term rct [93] , investigating vitamin d supplementation and the incidence of cancer and precancerous lesions in a high-risk population (overweight adults with prediabetes), will provide further and important data on the causality. several studies demonstrated a link between 25(oh)d levels and diabetes, and revealed a higher frequency of vitamin d deficiency in patients with type 1 diabetes mellitus (t1dm) compared with healthy individuals [94] [95] [96] [97] . investigating prenatal vitamin d exposure of the fetus, a lower gestational 25(oh)d level [98] or avoiding vitamin d-fortified food [99] was significantly associated with higher risk of developing t1dm. in infancy, vitamin d supplementation [100] or vitamin d-fortified margarine [99] was shown to reduce the risk of developing type 1 diabetes mellitus. the effect of vitamin d supplementation on t1dm onset seems to be dependent on life stage. supplementation between 7 and 12 months of age resulted in an almost twofold lower risk of developing t1dm compared with earlier supplementation [101] . in adolescents, many studies revealed no association between 25(oh)d level and onset of t1dm [102] [103] [104] . however, there is a clear effect of vitamin d in young adults, as low 25(oh)d levels were significantly associated with developing t1dm [105] . however, according to the available literature, the cause-and-effect relationship is inconclusive. on the other hand, diabetes per se results in physiological changes too, such as increased renal elimination of vitamin d-binding protein compared with healthy individuals [106] . therefore, the value of hypovitaminosis d as a trigger for developing t1dm remains unclear. vitamin d deficiency was also shown to have a negative impact on insulin resistance [107] . hence, a higher risk of developing type 2 diabetes mellitus (t2dm) in individuals with low 25(oh)d levels was assumed. however, vitamin d supplementation did overall not result in a lower risk of developing t2dm [6, 108] . in the recent d2d study by pittas et al., vitamin d did not significantly reduce new onset of diabetes, but vitamin d deficiency was no inclusion criterion, and only a minority of included patients had a 25(oh)d level <50 nmol//l (or 20 ng/ml). moreover, the hypothesized treatment effect used for the sample size calculation was relatively large (hazard ratio 0.75 for the vitamin d group). the actual hazard ratio for vitamin d as compared with placebo was 0.88 (95% confidence interval, 0.75-1.04; p = 0.12). interestingly, the effect appeared to be stronger in patients with a bmi <30. however, a post hoc subgroup analysis of individuals with a 25(oh)d level below 12 ng/ml (30 nmol/ l) revealed a significantly reduced risk of developing t2dm (hazard ratio 0.38; 95% ci, 0.18-0.80). the detrimental effects of vitamin d deficiency on the musculoskeletal system were the first visible mode of action that was attributed to vitamin d (i.e., rickets in children). the necessity of an adequate vitamin d status for muscle and bone health is undebated, and therefore not discussed in detail in this review. vitamin d intoxication is rare and usually only occurs at very high supplementation doses [109] . however, various mutations in vitamin d metabolizing enzymes that may lead to increased sensitivity to standard vitamin d supplementation or even endogenous vitamin d intoxication with hypercalcemia, hypercalciuria, and nephrocalcinosis/ chronic renal insufficiency have been described [110] . typically, these mutations affect cyp24a1, the enzyme that catabolizes 1,25ohd2 to the inactive metabolite 24,25ohd2. therefore, a diagnosis can be made by using the ratio of 24,25:25 d and does not necessarily require genetic testing. this condition has been termed idiopathic infantile hypercalcemia, but due to the greatly varying clinical phenotypes, patients may well become symptomatic only in adulthood. currently, no causal treatment is available, but avoidance of a high-calcium diet, uv-b exposure, and vitamin d or calcium supplements is advised. vitamin d deficiency is highly prevalent, but the literature to support vitamin d supplementation is unsatisfactory to date. unless major funding sources are used for vitamin d research, it appears sensible to focus on vitamin d-deficient populations with a high event rate. vitamin d is clearly not a panacea, but may be an important, inexpensive, and safe adjuvant therapy for many diseases and stages of life, including pregnancy, childhood, and old age. public health efforts to prevent severe vitamin d deficiency should therefore be further promoted. in the critically ill setting, one large vitamin d supplementation trial has recently been published (violet [111] ) and one is still ongoing (nct03096314 and nct03188796). violet randomized patients with 25 (oh)d levels below 50 nmol/l (or 20 ng/ml) "at risk for ards" to one single high dose of vitamin d3 (540,000 iu), and evaluated its effect on the primary outcome: 90-day mortality. it was prematurely stopped in mid-2018 after inclusion of ca. one-third of the patients originally planned, and no differences in mortality and secondary endpoints have been reported, with no differences in subgroup analyses and safety endpoints [111] . vitdalize is a european multicenter rct, including severely vitamin d-deficient icu patients with a 25 oh d level <30 nmol/l (or 12 ng/ml), and randomizes patients to a loading dose of oral/enteral vitamin d3 (540,000 iu) followed by 4000 iu daily for 90 days, with the primary outcome being 28-day mortality. recruitment is ongoing in austria and belgium, should be expanded to other european countries in 2020, and will likely continue for a few more years. conflict of interest ka has received speaker honoraria and an unrestricted grant from fresenius kabi. the other authors declare that they have no conflict of interest. publisher's note springer nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. trends in the incidence of testing for vitamin d deficiency in primary care in the uk: a retrospective analysis of the health improvement network (thin) vitamin d deficiency in europe: pandemic? association between vitamin d supplementation and mortality: systematic review and meta-analysis when not to use metaanalysis: analysing the meta-analyses on vitamin d in critical care vitamin d and energy homeostasis: of mice and men vitamin d supplementation and prevention of type 2 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levels are lower in australian children and adolescents with type 1 diabetes than in children without diabetes high prevalence of vitamin d deficiency among newly diagnosed youth-onset diabetes mellitus in north india. arquivos brasileiros de endocrinologia metabologia vitamin d status, enterovirus infection, and type 1 diabetes in italian children/adolescents low serum vitamin d status is associated with high prevalence and early onset of type-1 diabetes mellitus in kuwaiti children maternal serum levels of 25-hydroxy-vitamin d during pregnancy and risk of type 1 diabetes in the offspring vitamin d fortification and seasonality of birth in type 1 diabetic cases: d-tect study vitamin d intake and risk of type 1 diabetes: a meta-analysis of observational studies use of cod liver oil during the first year of life is associated with lower risk of childhood-onset type 1 diabetes: a large prevalence of vitamin d deficiency in pre-type 1 diabetes and its association with disease progression serum 25-hydroxyvitamin d concentrations in children progressing to autoimmunity and clinical type 1 diabetes no association of vitamin d intake or 25-hydroxyvitamin d levels in childhood with risk of islet autoimmunity and type 1 diabetes: the diabetes autoimmunity study in the young (daisy) immunomodulatory effect of vitamin d and its potential role in the prevention and treatment of type 1 diabetes mellitus-a narrative review enhanced excretion of vitamin d binding protein in type 1 vitamin d deficiency 2.0: an update on the current status worldwide diabetes: a role in vitamin d deficiency? association of vitamin d with insulin resistance and β-cell dysfunction in subjects at risk for type 2 diabetes rationale and design of diabetes prevention with active vitamin d (dpvd): a randomised, double-blind, placebocontrolled study development of vitamin d toxicity from overcorrection of vitamin d deficiency: a review of case reports mutations in cyp24a1 and idiopathic infantile hypercalcemia early high-dose vitamin d3 for critically ill, vitamin d-deficient patients effect of high-dose vitamin d3 on hospital length of stay in critically ill patients with vitamin d deficiency: the vitdal-icu randomized clinical trial key: cord-291340-8gj0ofmp authors: misra, anoop title: balanced nutrition is needed in times of covid19 epidemic in india: a call for action for all nutritionists and physicians date: 2020-08-27 journal: diabetes metab syndr doi: 10.1016/j.dsx.2020.08.030 sha: doc_id: 291340 cord_uid: 8gj0ofmp nan diet in patients not infected with covid19 infection, having mild covid19 as well as those who have recovered from covid19 infection should be balanced. it is reasonable to suggest that all individuals should continue to follow principles of healthy diets, and specific recommendations about consumption of sugar, salt, refined carbohydrates, edible oil, saturated fats and trans fatty acids, total dietary fibre, processed and canned foods [15] [16] [17] . particularly diets which require major changes in macro-and micronutrients and fasting (e.g. ketogenic diets, intermittent fasting) must be avoided during this time. there is some research which supports that specific foods and dietary nutrients may decrease risk of viral infections. in this context proteins, vitamins, minerals, trace elements, prebiotics, probiotics, omega-3 polyunsaturated fatty acids and specific diets have been researched, but direct research on covid19 patients are lacking. in the following paragraph we summarise the role of some specific nutrients vis-a-vis immunity. intake of certain nutrients may be the reason behind variations to susceptibility of individuals or populations to covid19. in this respect, the effect of some nutrients on angiotensin-converting enzyme (ace2) receptor, which facilitates entry of sars-coronavirus-2 to human cells, needs further discussion. theoretically, any inhibition of ace enzyme would lead to changed metabolic pathways which has potential for lung protection. broccoli protein hydrolysate has shown to have angiotensin-converting enzyme (ace) inhibitory activity in vitro and hypotensive effect in vivo [18] . some dairy products, eggs etc. may also have capacity for ace inhibition [19] , while saturated fat increases ace levels [20] . cabbage contains precursors of sulforaphane, which is an active natural activator of nuclear factor (erythroid-derived 2)-like 2 (nrf2), which influences angiotensin ii receptor type 1 axis. fermented vegetables contain many lactobacilli, which are also potent nrf2 activators [21] . these authors point out that populations in eastern asia, central europe or the balkans eat large quantities of fermented foods, which has implications to covid19 related mortality [21] . clinical benefits of these foods in context of covid19 are yet to be proved. there is no doubt that protein deficiency must be avoided. protein undernutrition can cause anaemia, vascular dysfunction, and impaired immunity. protein intake must be adequate even in healthy elderly since low albumin levels predict increased mortality [22] . research on micronutrients and minerals regarding immunity is a continuing area of interest. vitamin c has been shown to be severely depleted in critically ill patients at admission, and more so in patients with sepsis. in such patients mega doses are required in grams [23] . importantly, pneumonia and other respiratory infections are commonly seen in severe vitamin c deficiency [24] . there is some evidence that vitamin c may reduce infections, vascular injury and inflammation in acute respiratory distress syndrome [24, 25] . it is possible, but not proven, that vitamin c status is severely low in covid19 associated pneumonia, however, more research is needed. probiotics have been shown to decrease growth of pathogenic bacteria, decrease inflammation and enhance immunity. in a cochrane review [26] , and other studies [27] probiotics were shown to decrease upper respiratory infections through their effect on the gut lung axis [28] role of several other nutrients and food constituents like vitamins(e, b) carotenoids, minerals (fe, zn, mg, cu, se), and polyphenols in immunity have been suggested because of their effects on inflammatory cascade, antioxidant activities and effects on nitrous oxide signalling pathways [25] (table 1) . recent data on status of vitamins b1, b6, b12, d (25-hydroxyvitamin d), folate, selenium, and zinc levels are available in 50 hospitalized korean patients with covid-19. among these, 76% patients were vitamin d and 42% were selenium deficient, while other vitamin and mineral deficiencies were not present [29] . in an comprehensive review of 662 studies, jayawardena et al [30] concluded that vitamins, a and d showed a potential benefit in viral diseases, particularly in people who are deficient. vitamin d has a role in immunomodulation, and its deficiency has been shown to be correlated to mortality in covid19 [31] , however, there are currently no intervention trials. among trace elements, selenium and zinc have also shown favourable immunomodulatory effects in viral respiratory infections [30] .regarding the former, sodium selenite, a most common water soluble selenium compound, can oxidize thiol groups in the virus protein disulfide isomerase resulting in its inability to penetrate the healthy cell membrane [32] . in this context, it is important to note that selenium deficiency was found to be associated with mortality in patients with covid19 [33] . zinc deficiency is common worldwide, and such individuals have an increased risk of acquiring viral infections such as hiv or hepatitis c virus [34] . in vero-e6 cells, zinc inhibited sars-coronavirus rdrp template binding and elongation [35] . however, its role in adult pneumonias or covid19 has not been proven. fish oils have some role in boosting immune functions, and decreasing inflammation and thrombotic events [36, 37] interestingly infusion of omega-3 fatty acid lipid emulsion in critically sick patients with sepsis was associated with improved survival [38] but research on patients with covid19 is lacking. a few researchers have suggested that coronaviruses use purine nucleotides which could promote rna synthesis [39] , hence low purine diets may be beneficial [27] . interestingly, curcumin has been shown to bind to target on the sars-cov-2 receptor [40] . when individuals have severe covid19 infections, marked nutritional deficiencies may rapidly occur due to increased energy expenditure (fever, mechanical ventilation), decreased intake (loss of appetite, nausea, vomiting, diarrhoea), accelerated metabolism and reduced synthesis of nutrients (e.g. proteins). it is important that such malnutrition is recognised quickly (one can resort to screening scores for malnutrition risk), particularly in vulnerable populations (e.g. elderly, those with multiple co-morbidities, cancer etc.) and given adequate importance and treated [36] . this could be achieved by oral nutritional supplements, enteral feeding with nasogastric tube, and parenteral nutrition (table 1) [15, 16, 30, 36, 41, 42] . medical nutrition therapy should be instituted as soon as possible after intensive care unit (icu)admission [42] . it is important that feeding formulas contain balance of macro-and micronutrients. details of intake of energy, protein and other nutrients are beyond purview of this article and other reviews should be referred [36] } [41, 42] . in hospitalised patients, maintaining good protein intake is important to avoid hypoalbuminemia. specifically, albumin levels may decrease rapidly due to preexisting poor nutritional status; inflammation, decreased production by liver, and acute severe catabolic state. several studies show that low albumin levels in hospitalised patients lead to increased mortality [43] [44] [45] , morbidity, increased icu stay and increased resource utilisation [44] . acute kidney injury, a known complication in patients with covid19, when complicated with hypoalbuminemia, may further increase mortality as shown in a meta-analysis [46] . controlled trials also show reduced complications when serum albumin level is adequate [44] .in a recent scoping review(four studies in patients with ventilator-related pneumonia and acute respiratory distress syndrome, and the other 4 in patients with ventilator-associated pneumonia), intravenous ascorbic acid, intramuscular cholecalciferol, enteral and intramuscular vitamin e, enteral zinc sulphate, and oral and parenteral glutamine were given as interventions. most (6/8) studies did not have baseline status of the nutrient of interest. the authors state it was not possible to evaluate efficacy of such interventions because of inadequate baseline data [47] . in the absence of clear and robust evidence showing efficacy of specific nutrients and minerals, it is best practice to rely on traditional dietary advice with enhanced servings of proteins, local and seasonal fruits and vegetables, overall rounding off to have a balanced diet. [47] (table 1) . we believe that the j o u r n a l p r e -p r o o f above knowledge and discussion on nutrition in covid19 will enable physicians and physicians to disseminate this knowledge. finally, a call for action by the nutritionist and physician community to proactively discuss and implement healthy dietary practices and appropriate nutrition in all individuals and admitted patients with covdid19 is crucial at this time. corresponding author: anoop misra national diabetes, obesity and cholesterol foundation (n-doc), and fortis cdoc hospital for diabetes, metabolic diseases and endocrinology new delhi, india. recommended: • fruits, vegetables, legumes (e.g. lentils, beans), nuts and whole grains e.g. unprocessed maize, millet, oats, wheat, brown rice or starchy tubers or roots such as potato, and foods from animal sources (e.g. fish, eggs, milk meat,). o daily:2 cups of fruit (4 servings), 2.5 cups of vegetables (5 servings), 180 g of grains, and 160 g of non-vegetarian foods (fish, lean meats, and poultry) • snacks: choose raw vegetables and fresh fruits rather than foods that are high in sugar, fats, or salt. covid-19 in people living with diabetes: an international consensus contentious issues and evolving concepts in the clinical presentation and management of patients with covid-19 infectionwith reference to use of therapeutic and other drugs used in co-morbid diseases (hypertension, diabetes etc) diabetes and covid-19: evidence, current status and unanswered research questions covid19 in south asians/asian indians: heterogeneity of data and implications for pathophysiology and research sugar intake, obesity, and diabetes in india abdominal obesity and type 2 diabetes in asian indians: dietary strategies including edible oils, cooking practices and sugar intake nutrition transition in india: secular trends in dietary intake and their relationship to diet-related non-communicable diseases epidemiology and determinants of type 2 diabetes in south asia diabetes in developing countries obesity in south asia: phenotype, morbidities, and mitigation. curr obes rep obesity and the metabolic syndrome in developing countries effects of nationwide lockdown during covid-19 epidemic on lifestyle and other medical issues of patients with type 2 diabetes in north india increase in risk for type 2 diabetes due to lockdown for covid19 pandemic in apparently non-diabetic individuals in india: a cohort analysis. diabetes and met syndr balanced diet is a major casualty in covid-19 food safety and standards authority of india (fssai consensus dietary guidelines for healthy living and prevention of obesity, the metabolic syndrome, diabetes, and related disorders in asian indians in vitro and in vivo studies on the angiotensin-converting enzyme inhibitory activity peptides isolated from broccoli protein hydrolysate food originating ace inhibitors, including antihypertensive peptides, as preventive food components in blood pressure reduction high-saturated-fat diet increases circulating angiotensin-converting enzyme, which is enhanced by the rs4343 polymorphism defining persons at risk of nutrient-dependent increases of blood pressure cabbage and fermented vegetables: from death rate heterogeneity in countries to candidates for mitigation strategies of severe covid-19 albumin levels as a predictor of mortality in the healthy elderly hypovitaminosis c and vitamin c deficiency in critically ill patients despite recommended enteral and parenteral intakes patients with community acquired pneumonia exhibit depleted vitamin c status and elevated oxidative stress diet supplementation, probiotics, and nutraceuticals in sars-cov-2 infection: a scoping review probiotics for preventing acute upper respiratory tract infections can probiotics and diet promote beneficial immune modulation and purine control in coronavirus infection? gut microbiota and covid-19-possible link and implications nutritional status of patients with coronavirus disease 2019 (covid-19) enhancing immunity in viral infections, with special emphasis on covid-19: a review vitamin d deficiency as a predictor of poor prognosis in patients with acute respiratory failure due to covid-19 selenium supplementation in the prevention of coronavirus infections (covid-19). med hypotheses selenium deficiency is associated with mortality risk from covid-19 the role of zinc in antiviral immunity zn(2+) inhibits coronavirus and arterivirus rna polymerase activity in vitro and zinc ionophores block the replication of these viruses in cell culture nutritional support in coronavirus a mixed flavonoid-fish oil supplement induces immune-enhancing and anti-inflammatory transcriptomic changes in adult obese and overweight women-a randomized controlled trial the impact of an omega-3 fatty acid rich lipid emulsion on fatty acid profiles in critically ill septic patients biochemical characterization of a recombinant sars coronavirus nsp12 rna-dependent rna polymerase capable of copying viral rna templates revealing the potency of citrus and galangal constituents to halt sars-cov-2 infection espen expert statements and practical guidance for nutritional management of individuals with sars-cov-2 infection management of critically ill patients with covid-19 in icu: statement from front-line intensive care experts in wuhan, china. ann intensive care low albumin levels are associated with mortality risk in hospitalized patients hypoalbuminemia in acute illness: is there a rationale for intervention? a meta-analysis of cohort studies and controlled trials hypoalbuminemia is a strong predictor of 30-day all-cause mortality in acutely admitted medical patients: a prospective, observational, cohort study hypoalbuminemia and acute kidney injury: a meta-analysis of observational clinical studies effects of micronutrients or conditional amino acids on covid-19-related outcomes: an evidence analysis center scoping review key: cord-339166-f7tw90tm authors: tecilazich, francesco; formenti, anna maria; giustina, andrea title: role of vitamin d in diabetic retinopathy: pathophysiological and clinical aspects date: 2020-10-07 journal: rev endocr metab disord doi: 10.1007/s11154-020-09575-4 sha: doc_id: 339166 cord_uid: f7tw90tm epidemiological data predict a dramatic increase in the prevalence of diabetes and of diabetic retinopathy (dr) – the most common complication of diabetes-for which however we do not have so far effective tools for prevention and treatment. since hypovitaminosis d is very frequent in patients with diabetes and vitamin d (vd) has vascular protective properties, several studies have addressed the association of vd deficiency with dr and its severity and progression, whereas the effects of vd supplementation on its natural history are largely unknown. here we review the available evidence that supports the possible protective role of vd in dr and suggests to determine the vd levels in dr patients calling for a definitive randomized clinical trial to ascertain whether vd supplementation could protect against dr. vitamin d (vd) is actually a steroid hormone produced in the skin after exposure to sun irradiation in the form of cholecalciferol. diet contribution to daily vd requirement does not exceed the 20% of total unless food is not systematically fortified with vd [1] . hepatic and kidney hydroxylation in position 25 and 1 respectively are necessary to produce active vd. kidney 1 alpha hydroxylase is under control of endogenous pth [1] (fig. 1 ). activated vitamin d, acts through its cognate vitamin d receptor (vdr) that encompasses two subtypes: the membrane-located mvdr, and the nuclear-located nvdr which are expressed in the majority of mesenchymally derived cells; mvdr regulates the non-genomic effects of vd, which are exerted within seconds to minutes after its activation, and is mainly involved in secondary signaling mechanisms implicated in channel responses, adipocyte metabolism, insulinotropic effects, and antiapoptotic pathways. conversely, nvdr regulates the genomic effects of vd, which are exerted within hours to days after its activation. once phosphorylated/activated, nvdr forms a trimer with the retinoid x receptor; this complex then binds to the vdr response element, leading to changes in transcription and expression of target genes [1] . recently, it has also emerged the role of circulating vd binding protein as a regulator of hormone bio-availability to target tissue with a clinically prevalent inhibitory effect on vd activity [3] . vd is crucial for the calcium and skeletal homeostasis in physiological and disease states [1, 4, 5] . it also has many systemic functions which are also known as extraskeletal effects [6] most of which are based on solid experimental evidences and positive observational studies, but less frequently on adequate randomized clinical trials [7] . among the numerous extraskeletal actions vd has been proposed to play a pivotal role in the regulation of fundamental processes involved in cardiovascular homeostasis [8] , as well as in the modulation of inflammation and tuning of the innate and adaptive immunity systems, which appear to be relevant in the response to respiratory viral infections [9] [10] [11] . moreover, several studies have addressed, without reaching to date an univocal conclusion, the prevalence and role of hypovitaminosis d in diabetes, as well as the impact of vd supplementation on the natural history of diabetes, blood fig. 1 metabolic pathways involved in the synthesis of vd, main external sources of vd and the potential mechanisms underlying widespread hypovitaminosis d (defined according to sempos et al., 2018 [2] glucose control, and prevalence and severity of its macro and microvascular complications [6, 12] . assessment of total 25ohvd is widely accepted as a marker of the vd status [2, 12] and is used by several agencies to support vitamin d dietary requirements and thresholds for hypovitaminosis d in population surveillance [2, 13, 14] . in fact, definition of vd deficiency is still an open issue, as apparent from different recommendations from various scientific bodies [15] . however, there is quite a strong agreement among experts that 25ohvd levels below 12 ng/ml (30 nmol/l) represent deficiency and levels above 30 ng/ml (75 nmol/l) are clearly sufficient. conversely, it is still unclear the clinical meaning of levels between 12 and 30 ng/ml (30 and 75 nmol/l) with thresholds of sufficiency at 20 ng/ml (50 nmol/l), [16] or ≥ 30 ng/ml (≥ 75 nmol/l) [17] according to different guidelines. these discrepancies are at least in part due to the lack of 25ohvd assay standardization [12] . in fact, due to progressive changes in lifestyle such as, indoor work extremized by confinement due to covid-19 pandemic [10, 11] , or sun avoidance, hypovitaminosis d is still widespread [17] . implementing the <20 ng/ml (<50 nmol/l) threshold [16] , approximatively one third of the world population is deficient with figures increasing to 40% in europe [18, 19] . severe vd deficiency, defined as <30 nmol/l (or < 12 ng/ml), can be found in about 7% of the global population [17] . according to the nhanes, a large cross-sectional study on over 8000 subjects, 42% of the us population display insufficient vd levels african-americans present the highest prevalence rate (82%), followed by hispanic-americans [20] . interestingly, epidemiological data show that italy is one of the countries with the highest prevalence of vd deficiency in europe [21] . a study from isaia et al. on 700 women aged 60-80 years in italy found values of 25ohvd lower than 5 ng/ml in 27% and lower than 12 ng/ml in up to 76% of enrolled subjects [22] . moreover, another italian study found a winter prevalence of hypovitaminosis d in as many as 32% of healthy postmenopausal women, and to 82% in patients engaged in long-term rehabilitation programs because of different neurological disorders [23] . as mentioned above, this widespread deficiency of circulating vd [24] besides its detrimental skeletal effects [25] has been linked to the development and progression of several diseases such as cancer [26] , obesity [27] , and healthy aging [28] . in vivo studies have shown that t2dm rats display lower levels of 1,25ohvd as compared to controls [29] , likely due to impaired hepatic and renal metabolism of vd [30] . reduced 25ohvd levels have been hypothesized to be involved in the pathophysiology of skeletal fragility of patients with diabetes and in patients in whom diabetes may develop due to glucocorticoid treatment or endocrine diseases [4, [31] [32] [33] . in fact, it has been consistently reported that patients with t2dm had decreased circulating levels of 25ohvd [34, 35] . interestingly, in an observational italian study on 66 women with t2dm out of a sample of about 800 postmenopausal women the prevalence of severe vd deficiency was significantly higher in diabetic vs control subjects (39 vs. 25%, respectively) [35] . recently, an association between low levels of circulating vd with poor glycemic control in patients with t2dm has also been reported [36] . low levels of circulating 25ohvd are very frequently found also in obese non diabetic subjects, and are inversely correlated with bmi and adiposity [37] . the copenhagen city heart study, a 29 year long prospective cohort study on nearly 10,000 patients, showed an association between low vd levels and increased risk of t2dm; in fact, the cumulative incidence of t2dm increased with decreasing vd concentrations at baseline, and when categorized by vd concentrations patients in the lowest quartile had an hazard ratio (hr) of 1.35 (95% ci 1.0.9-1.66) of developing t2dm [38] . moreover, a historical prospective cohort study on over 100,000 subjects showed that patients with levels of vd <25 nmol/l had increased odds of transitioning from normal to impaired fasting glucose (or 1.13, 95% 1.03-1.24), from normoglycemia to diabetes (or 1.77, 95% 1.11-2.83), as well as from impaired fasting glucose to diabetes (or 1.43, 95% 1.16-1.76) [39] . a recent study and a meta-analysis of rcts showed that vd supplementation in t2dm patients can improve hba1c, insulin resistance, and insulin secretion in short-term intervention [40, 41] . another meta-analysis of rcts showed, a favourable effect of vd administration on fasting glucose only in patients with poorly controlled diabetes [42] . in a recent meta-analysis of interventional studies in obese non diabetic patients no clear evidence for a beneficial effect of vd supplementation on weight loss or cardio-metabolic parameters was reported [43] . this may at least in part due to a vd "resistant state" which is consistently reported in obesity [44, 45] . in a recent multicenter, randomized, placebo-controlled trial involving more than 2.400 subjects at high risk for t2dm not necessarily vd deficient, vd 3 supplementation did not significantly lower the risk of diabetes when compared to placebo, after a median follow-up of 2.5 years [46] . however, in a post hoc analysis of the same study data from subjects with a baseline 25ohvd less vs greater than 12 ng/ ml (30 nmol per liter) the hazard ratio favoured vd treatment [46] . in the tromsø vd and t2dm trial on 511 subjects with prediabetes a slightly but not significantly lower risk of progression to diabetes was observed in the vd vs placebo treated groups [47] . both trials were not powered to detect the10-15% observed reduction of diabetes risk among persons at risk for diabetes. moreover, as many other vd trials the enrollment of large number of vd sufficient subjects likely heavily impacted on the conclusions [48] . data on the effects of vd on cardiovascular risk and complications of diabetes are controversial. a recent rct on over 25,000 patients found that vd supplementation for five years had no cardiovascular protective effect (hr 0.97, 95% ci 0.85-1.12; p = 0.65) [49] ;. however, these results may have been affected by selection bias of subjects without vd deficiency [7] . indeed, other reports led to different results. in fact, meta-analyses show that hypovitaminosis d could reduce cardiovascular risk [50, 51] . moreover, clinical studies showed that vd deficiency is linked to surrogate parameters of cardiovascular damage such as endothelial dysfunction, assessed as flow mediated dilation at the brachial artery [52] , as well as with carotid intima-media thickness [53] . mechanistic studies show that vd played a pivotal role in vascular protection and regeneration [54, 55] , and that normalization of vd levels may significantly improve indexes of vascular function [56] [57] [58] . vd has also been reported to have protective roles against cerebrovascular complications [59] . diabetic nephropathy is one of the most common causes of chronic kidney disease. microalbuminuria and proteinuria are characteristic markers of this complication [60, 61] . in a metaanalysis of 9 rcts a positive but not significant trend towards a vd mediated reduction in albuminuria and its possible role in slowing progression of diabetic nephropathy has been hypothesized [62] . a significant difference in 25ohvd levels in patients with painful diabetic peripheral neuropathy, has been recently consistently reported [63] . treatment with vd in patients with painful diabetic neuropathy has also been associated with a significant decrease in the symptoms of the disease [64] . a recent meta-analysis on 35 prevalence studies as well as on 4 incidence studies of diabetic eye disease (ded) among individuals with diabetes in europe has recently been published [65] . any diabetic retinopathy (dr) was prevalent in 25.7% (95% ci 22.8-28.8%) being significantly higher in persons with t1dm as compared to persons with t2dm (54.4% vs. 25.0%). the pooled mean annual incidence of any dr in patients with t2dm was 4.6% (95% ci 2.3-8.8%). authors estimated that persons with diabetes affected by any ded in europe will increase from the current 6.4 million to 8.6 million in 2050, of whom 30% require close monitoring and/or treatment. it is noteworthy that currently there are no widely effective interventions that can be used to prevent and/or to treat dr in addition to optimization of glucose control and blood pressure. large epidemiological studies have shown that the threshold for the appearance of dr is at hba1c levels of 6.5%, just above the upper limit of normal [66] . however, this biochemical target is not often reached despite intensive follow-up and residual hyperglycemia exposes to an increased risk of dr as well as of other serious complications [67] . further intensification of treatment to maintain hba1c below 6% with the modalities available today poses severe risks of hypoglycemia in t2dm patients with increased mortality [67] . in this perspective, local and systemic treatments with biological compounds as well as with the somatostatin analog octreotide [68] [69] [70] are promising additional tools. in 2000, aksoy et al. found an inverse relationship between presence and severity of dr, and vd concentrations, being the lowest in proliferative dr and the highest in diabetic patients without dr [71] . in 2011, a cross-sectional study on over 500 patients showed that vd deficiency was associated with increased prevalence of dr in t1dm patients; in this study, the prevalence of dr was double in vd deficient vs.vd sufficient patients (18% vs 9%, respectively; p = 0.02); and in logistic regression, dr was associated with vd deficiency (or 2.12 [95% ci 1.03-4.33]) [72] . similarly, a retrospective cross sectional study on nearly 1000 patients from the nhanes showed that the prevalence of severe and mild dr were higher in poorly controlled patients with hypovitaminosis d vs. vd sufficient patients; in addition, a multivariate ordinal regression analysis on this database showed an association between vd deficiency and dr severity (or 2.22, 95% ci: 1.36, 3.65) [73] (table 1) . these data were confirmed by meta-analyses. one was performed on over 17,000 subjects from fifteen observational studies, and showed that t2dm patients with vd deficiency had an increased risk of dr (or = 2.03, 95% ci: 1.07, 3.86); furthermore, patients with dr displayed a decrease in vd levels of 1.7 ng/ml (95% ci: −2.72, −0.66) [79] . another was performed on over 10,000 participants from fourteen observational studies, and showed a significant association between dr and vd deficiency (or = 1.27, 95% ci: 1.17, 1.37; p = 0.001); furthermore, patients with dr displayed a decrease in vd of 1.32 ng/ml (95% ci: −2.50, −0.15) [80] . in addition, a multitude of cross-sectional studies also very recent [74] performed in different populationssuch as italian [75] , japanese [76] , chinese [77] , and african-american [78]reported consistent data ( table 1 ). the high reproducibility of the findings, and their cross-ethnicity, strengthened the hypothesis of an association of vd with dr, and attenuated the concerns raised by two studies in this regard. in fact, a prospective observational study showed that vd deficiency independently predicted all-cause mortality, but not the development of microvascular complications [81] . moreover, a sub-analysis of the veteran affairs trial reported that vd status had no impact on the incidence of vascular events in high-risk veterans with diabetes [82] . noteworthy, a sub-analysis of the field study, a placebo-controlled trial on nearly 10,000 t2dm patients, showed that subjects with hypovitaminosis d had a higher cumulative incidence of microvascular events; in fact, a 50 nmol/l difference in vd levels was associated with a 18% (p = 0.007) increase in risk of microvascular complications [83] . more recently, a sub-analysis of the rotterdam study, a prospective cohort study on over 5500 patients, showed that patients with hypovitaminosis d were at increased risk for dr, independently of the presence of cardiovascular risk factors [84] . the active form of vd calcitriol supplementation has been shown to attenuate ex vivo and in vivo choroidal vasculature angiogenesis [85] . however, despite the reasonable rationale provided by the above discussed association data prospective studies on the effect of vd administration on dr in humans are lacking. in fact, although treatment of dr is often associated with the administration of dietary supplements [86] only very few studies specifically supplementing vd in patients with dr have been published so far [87] [88] [89] . these were short term studies mainly focusing on biochemical, immunological and inflammatory markers of vascular damage in patients with furthermore, there was a significant decrease in il-6, fasting insulin and homa-ir in intervention group after 3 months supplementation [90] . finally, interim results of a small and short-term (6 months) ongoing non-randomized clinical study [91] provided encouraging results. however, the short duration of follow-up, uncontrolled nature and small number of patients are important limiting factors and do not allow any inference on the possible protecting role of vd supplementation on dr in humans with or without vd deficiency. vd protects vessels against diabetes via several intertwined mechanisms. al mheid et al. showed that vd status is independently associated with digital reactive hyperemia index (rhi), a marker of microvascular function, in healthy subjects; notably, the authors also found a significant increase in rhi in vd deficient patients after 6 months of vd oral supplementation [56] . similarly, a study reported the association between vd and microvascular function, measured as rhi, in healthy women [92] . in addition, an association between vd and vascular function has been described in patients with diabetes [93] ; moreover, a report described improved vascular function parameters in patients with diabetes, after vd oral supplementation [94] . furthermore, in patients with diabetes and vd deficiency reduced endothelium-dependent microvascular function, assessed by iontophoresis of acetylcholine, when compared to patients with diabetes and non-deficient vd levels [95] . experimental studies have shown that vd improves endothelial dysfunction and promotes vascular regeneration through the activation of vdr, that in turn regulates the expression of numerous genes involved in fundamental processes of potential relevance to cardiovascular function [96] ; in fact, the suppression of vdr in endothelial cells (ec) alters vascular homeostasis [1, 97] . it is noteworthy that vdr is expressed in ec, pericytes, and vascular smooth muscle cells (vsmc). here we will review a selection of the putative mechanisms possibly involved in specific vd protective effects against dr (fig. 2) . vd increases enos-dependent no production vd promoted no production in ec [93] ; in addition, in endothelial-specific vdr −/− mice reduced endothelial no synthase (enos) expression was reported [1] . in the presence of oxygen, nadph and other co-factors, enos catalyzes the oxidation of larginine to form l-citrulline and no. no is a gas that easily diffuses across the cell membrane to the adjacent vsmc where it leads to a cascade of events, resulting in vsmc relaxation and thereby dilation of the vessel. in addition, no is known to exert vasculo-protective activities, such as enhancement of endothelial cell survival [98] and inhibition of platelet aggregation. finally, no has key role in the pathogenesis of dr [99] and its modulation by vd may have protective effects in dr. vd reduces oxidative stress in diabetic mice vd mitigates oxidative stress through a multitude of intertwined mechanisms, such as enhancing the antioxidant defence systems [100] , preserving mitochondrial function [100] , restoring enos function (see above), and reducing the activation of monoamine oxidases (mao) [101] . interestingly, a recent study demonstrated that exposure to a high level of glucose caused upregulation of pro-inflammatory cytokines and a decrease in anti-oxidant enzyme expression both in vitro and in vivo. vd treatment increased cell viability, reduced reactive oxygen species production and caspase-3/7 activities in highglucose-treated retinal pigmented epithelial cells suggesting that vd can protect the retina from high-glucose-induced oxidative damage and inflammation [102] . vd enhances vascular endothelial growth factor (vegf) synthesis and release vegf has a key pathogenetic role in proliferative dr [103] . vd induces up-regulation of vegf and of its receptors, by direct binding of vdr to two areas of the vegf promoter [104] . vegf primarily exerts its effect in dr through the production of vasodilatory mediators. in addition, vegf signalling through its cognate receptor, increases enosindirectly via calmodulin, directly via phosphorylation of enos, and via increase of enos levelsand thereby increases no; moreover, vegf promotes production of the vasodilatory prostanoid prostacyclin (pgi2) through activation of phospholipase a2 via plcγ/pkc, and plays a pivotal role in vascular regeneration [105] . interestingly, vdr agonists were found to have significant and selective retinal antiangiogenic properties modulating expression of vegf in zebrafish [106] and in diabetic rats [107] . vd modulates inflammation and the immune system immune and inflammatory mechanisms also associated with diabetic gut microbiota dysbiosis [108] [109] [110] may play a role in the pathogenesis of dr. vd on the one hand reduces chronic inflammation [111] by inhibiting the activation of the ros/ txnip/nlrp3 inflammasome pathway [112] , and by suppressing the nuclear factor-κappab (nf-κb) signalling pathway [113] . on the other hand, vd plays major role in the immune-system vascular activities: in fact (a) it increases the activity of myeloid angiogenic cells, by restoring their function and by enhancing their recruitment [54, 55] ; (b) it modulates the immune system [114] , by promoting the innate immune response and inhibiting the adaptive immune response [9] , and by regulating regulatory t cells and immature dendritic cells, and thereby halting the progression of angiopathy [115] ; and (c) it decreases the number and activation of macrophages and dendritic cells in the retina [116] . interestingly, vd decreased diabetes-induced ros and exerted protective effects against retinal vascular damage and cell apoptosis in association with inhibition of the ros/ txnip/nlrp3 inflammasome pathway in diabetic rat and in human retinal cells [116] . furthermore, patients with proliferative dr were reported to have decreased serum level of 1,25ohvd and increased production of ifn-γ, tnf-α, il-6, and il-17a, by anti-cd3 and anti-cd28 antibodies activated pbmcs whereas 1,25ohvd significantly inhibited the proliferation of pbmcs, as well as the secretion of ifn-γ, tnf-α, il-6, and il-17a [117] . vd reduces transforming growth factor-β (tgf-β) production pre-treatment of mesothelial cells with vd inhibits high glucose and lps-induced tgf-β production [118] . accordingly, diabetic rats receiving vd showed lower levels of tgf-β in the retina, when compared to non-vd treated diabetic controls [107] . in addition, vd has been shown to reduce urinary tgf-β levels as well as albuminuria in diabetic patients in both a prospective clinical study [63] , as well as in a randomized double-blind controlled study [119] . tgf-β plays a pivotal role in retinal microvascular homeostasis [120] . indeed, tgf-β regulates the production of extracellular matrix, the replication and survival of ec, the interactions of ec and pericytes to ensure vessel stability, and the remodelling of vessels [121, 122] . when tgf-β signalling in vascular cells is increased vessels in the retina may show excess extracellular matrix, tortuosity, and aneurysms [123] . in fact, tgf-β has been suggested to be one of the possible biomarker of dr [124, 125] . vd regulates the activation of the complement cascade vd reduces circulating c3 by modulating liver inflammation and by decreasing c3 secretion from adipocytes [126] . it is noteworthy that in diabetes complement dysregulation plays a role in the pathogenesis of diabetic retinopathy [127] ; in fact, microvessels from animals and patients with short duration of diabetes display terminal products of complement activation, whereas healthy controls do not [128] . these alterations lead to increased presence and size of microthrombi, that are topographically associated with apoptotic cells, and that can contribute to capillary obliteration and retinal ischemia [129] . vd inhibits the renin-angiotensin aldosterone system (raas) high blood pressure is known to be associatd with dr [130] and upregulation of raas has been reported among the pathogenetic mechanisms of dr [131] . several clinical studies have reported an inverse relationship between circulating vd levels and plasma renin activity [132] . in addition, vd vitamin d shields vessels against diabetes via several intertwined pathways: it enhances the activities of no, vegf, sdf-1, and antioxidant systems, while downregulating ages, tgf-β, raas, c3, er stress, and apoptosis. altogether, vitamin d leads to a complex antiinflammatory, anti-adhesive, anti-apoptotic, vasculo-protective phenotype. abbreviations: vd, vitamin d; no, nitric oxide; vegf, vascular endothelial growth factor; ages, advanced glycation endproducts; tgf-β, transforming growth factor-β; raas, reninangiotensin aldosterone system; sdf-1, stromal cell-derived factor 1; c3, c3 complement factor; er, endoplasmic reticulum; ec, endothelial cells; mac, myeloid angiogenic cells suppresses renin transcription by a vdr-mediated, but not calcium-dependent, mechanism [133] . indeed, raas has pro-inflammatory and pro-fibrotic effects at cellular and molecular levels; in addition, raas induces vascular remodelling via modification of the extracellular matrix composition, that causes structural and functional changes in blood vessels [130, 131] , vd reduces the detrimental effects of advanced glycation end products (ages) vd supplementation in t2dm patients down-regulates the levels of ages and the gene expression of its cognate receptor (rage); these mechanisms appear to be at least in part mediated by glyoxalase i enzyme (glo1)an enzyme involved in the degradation and removal of ages as vd supplementation tends to increase its expression [134] . in addition, vd modulates the vascular effects of ages by reducing the diabetes-induced increase of il-6 and of nfκb-p65 dna binding activity, both key mediators of ages signalling [135] . ages and rage are among the major pathways involved in the pathophysiology of diabetic complications and of dr [136] , as their interaction induces the translocation of nf-κb, and the subsequent transcription of endothelial dysfunction biomarkers, such as intercellular adhesion molecule-1 (icam-1), endothelin-1, and e-selectin [137] . vd reduces endoplasmic reticulum (er) stress vd decreases the expression of the classical er stress pathway perk-eif2a-atf4-chop, by modulating the activity of grp78a master regulator of er stress [138] . moreover, vdsufficient patients showed lower er stress in monocytes as compared to vd deficient patients [139] ; in addition, the deletion of the vdr in macrophages from t2dm patients activated er stress, and induced a pro-adhesive phenotype in monocytes. indeed, diabetes promotes the expression of endogenous biomarkers of er stress, among which grp78, a member of the heat shock protein family. interestingly, also er stress has been related to dr [140, 141] . vd regulates apoptosis of endothelial cells vd induces an overall pro-survival transcriptional program characterized by upregulated expression of anti-apoptotic genes and downregulated expression of pro-apoptotic genes [142] ; in addition, vd determines the non-genomic activation of the pi3k-akt survival kinase pathway [143] , it also reduces apoptosis of ec by increasing no production (see above). other possible mechanisms based on the body of evidences presented above it is reasonable to hypothesize that vd could exert its vascular protective activities also by regulating diabetic leukostasis, and/or by improving the myogenic response of microvessels. diabetic leukostasis is a phenomenon observed in diabetic retinal vessels, which has been proposed to be implicated in the pathogenesis of dr [144] . even though there are currently no data on the effect of vd on leukostasis, it can be hypothesized that vd may co-orchestrate the response of immune cells to the stressed microvessels, thereby modulating neighbouring leukocytes, repairing cellular damage/alterations, and maintaining vascular homeostasis. in contrast, the myogenic response is the constriction of the afferent arterioles to increases in perfusion pressure, in order to dampen the transmission of pressure to capillaries and parenchyma. thus, the impaired myogenic response induced by diabetes appears as a mechanism for accelerating microangiopathy [145] . to date, there are no evidences on the effect of vd on the impaired myogenic response in diabetes. however, the molecular actions described above, coupled with its activities on vsmc function [146, 147] , suggest the hypothesis that vd could protect retinal microvessels against diabetes at least in part via restoring the myogenic response. the above reviewed clinical and pathophysiological aspects suggest that vd deficiency may be implicated in the development and progression of dr. since hypovitaminosis d is widespread and heavily impacts in the whole world [13] , and is related also to development and natural history of t2dm, it can be suggested to determine the levels of vd in dr patients. moreover, it can be suggested to integrate vd with cholecalciferol in patients with dr and severe vd deficiency, as well as in the general population [148] . over the last years the quest for adjunct drugs for the prevention and treatment of dr has made little progress; in fact, so far prevention and treatment attempts of dr mainly consisted of drugs that target the pathways of glucose toxicity or discrete molecular abnormalities caused by diabetes [149] . the theoretical added value of vd could be to provide a broad protection to vascular cells enhancing vascular repair, reversing endothelial dysfunction, decreasing inflammation, and/or oxidative stress. all the above considerations provide a strong rationale for a well-designed, placebo-controlled, randomized clinical trial to learn whether vd supplementation protects against dr onset and/or progression. knowing that vd protects retinal microvessels against diabetes and exerts beneficial effects on endothelial dysfunction may be of high clinical relevance. in fact, since vd deficiency is extremely common, particularly in patients at increased 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to declare. key: cord-013342-vx3eor43 authors: silwal, prashanta; paik, seungwha; jeon, sang min; jo, eun-kyeong title: nuclear receptors as autophagy-based antimicrobial therapeutics date: 2020-08-27 journal: cells doi: 10.3390/cells9091979 sha: doc_id: 13342 cord_uid: vx3eor43 autophagy is an intracellular process that targets intracellular pathogens for lysosomal degradation. autophagy is tightly controlled at transcriptional and post-translational levels. nuclear receptors (nrs) are a family of transcriptional factors that regulate the expression of gene sets involved in, for example, metabolic and immune homeostasis. several nrs show promise as host-directed anti-infectives through the modulation of autophagy activities by their natural ligands or small molecules (agonists/antagonists). here, we review the roles and mechanisms of nrs (vitamin d receptors, estrogen receptors, estrogen-related receptors, and peroxisome proliferator-activated receptors) in linking immunity and autophagy during infection. we also discuss the potential of emerging nrs (rev-erbs, retinoic acid receptors, retinoic acid-related orphan receptors, liver x receptors, farnesoid x receptors, and thyroid hormone receptors) as candidate antimicrobials. the identification of novel roles and mechanisms for nrs will enable the development of autophagy-adjunctive therapeutics for emerging and re-emerging infectious diseases. the nr superfamily classes are divided into four classes based on structural and functional characteristics, i.e., steroid receptors (class i), retinoid x receptor (rxr) heterodimers (class ii), homodimeric orphan receptors (class iii), and monomeric orphan receptors (class iv) [15, 61] . the nr superfamily is classified as the endocrine, adopted orphan, and orphan subfamilies, depending on the existence of ligands [61] (figure 1 ). the differences in nr classes include their biological function, binding to a ligand or dna, and tissue specificity. all members of the nr superfamily have a variable n-terminal domain (ntd), a dna binding domain (dbd), a ligand-binding domain (lbd), and a variable c-terminal domain. nr dbd contains different dna-binding recognition sequences and two zinc finger motifs for binding to chromatin [61, 62] . nrs play a crucial role in the recruitment of co-activators within the nucleus, although there is marked variability among the binding of ntds to co-activators [15] . autophagy processes such as macroautophagy, lc3-associated phagocytosis (lap), and xenophagy involve different autophagy-related genes (atgs) or cargo receptors, such as p62, ndp52, and optineurin. the upper panel highlights the different sets of autophagy genes involved in vesicle nucleation, autophagosome formation, and the maturation of autolysosomes. the nr superfamily classes are divided into three or four subclasses according to their structural and functional characteristics and their ligands. nrs are implicated in the regulation of autophagy at transcriptional and post-translational levels. understanding the mechanisms by which nrs regulate the expression and post-translational modification of atgs will facilitate the development of novel host-directed antimicrobial agents. a total of 48 intracellular proteins have been identified as nrs [63] ; among them, several members are critical in the regulation of host immune responses to infection. these nrs include the vitamin d receptor (vdr), also known as nuclear receptor subfamily 1, group i, member 1 (nr1i1) [64] [65] [66] ; estrogen-related receptor-α (errα; esrra; nr3b1) [20, 67] ; errγ (esrrg; nr3b3) [68] ; liver x receptor-α (lxrα; lxra; nr1h3) [69] ; peroxisome proliferator-activated receptor-α (pparα; autophagy processes such as macroautophagy, lc3-associated phagocytosis (lap), and xenophagy involve different autophagy-related genes (atgs) or cargo receptors, such as p62, ndp52, and optineurin. the upper panel highlights the different sets of autophagy genes involved in vesicle nucleation, autophagosome formation, and the maturation of autolysosomes. the nr superfamily classes are divided into three or four subclasses according to their structural and functional characteristics and their ligands. nrs are implicated in the regulation of autophagy at transcriptional and post-translational levels. understanding the mechanisms by which nrs regulate the expression and post-translational modification of atgs will facilitate the development of novel host-directed antimicrobial agents. a total of 48 intracellular proteins have been identified as nrs [63] ; among them, several members are critical in the regulation of host immune responses to infection. these nrs include the vitamin d receptor (vdr), also known as nuclear receptor subfamily 1, group i, member 1 (nr1i1) [64] [65] [66] ; estrogen-related receptor-α (errα; esrra; nr3b1) [20, 67] ; errγ (esrrg; nr3b3) [68] ; liver x receptor-α (lxrα; lxra; nr1h3) [69] ; peroxisome proliferator-activated receptor-α (pparα; ppara; nr1c1) [70] [71] [72] ; pparγ (pparg; nr1c3) [73] [74] [75] ; the glucocorticoid receptor (gr; gcr; nr3c1) [76] ; estrogen receptor-α (erα; esr1; nr3a); erβ (esr2; nr3a2) [77, 78] ; the xenobiotic pregnane x receptor (pxr; nr1i2) [79] [80] [81] ; rev-erb-α (rev-erbα; nr1d1) [82, 83] ; farnesoid x receptors (fxrs; nr1h4) [75, 84] ; nuclear receptor 4a (nr4a) family members; nuclear receptor related 1 protein (nurr1; nr4a2); and neuron-derived orphan receptor 1 (nor1; nr4a3) [85] . the nrs are endogenously activated by small lipophilic ligands, such as steroid hormones, retinoids, and phospholipids; however, some of the nrs have been classified as 'orphan' members as their ligands have not yet been identified [86] . the ligands can cross the plasma membrane, directly interact with nrs inside the cells, and modulate gene transcription through different mechanisms [87] . in class i nrs or steroid receptors, ligand binding at the plasma membrane is followed by a signal transduction cascade including enzymatic phosphorylation, which results in the translocation of transcription factors into the nucleus [61, 88] . er, a member of the class i nr superfamily, is anchored in the cytoplasm by a chaperone protein such as heat shock protein 90 (hsp90). after ligand binding, the receptor is freed from the chaperone, causing homodimerization and nuclear translocation. in the nucleus, the ligand-receptor complex associates with the transcriptional coactivator and activates the target gene [89] . selective estrogen receptor modulators (serm) such as tamoxifen and bazedoxifen have been suggested to have antimycobacterial activity [90, 91] . the class ii receptor family includes the thyroid hormone receptor (tr), vdr, retinoic acid receptor (rar), and ppar [61] . they are typically present in the nucleus and generally form heterodimers with rxr [92] . the heterodimers are bound to their response element, even in the absence of a ligand, where gene activation is repressed through interaction with a nuclear co-repressor (ncor) and silencing mediator for retinoic acid and thyroid hormone receptor (smrt) corepressor complexes. binding of the ligand causes displacement of the ncor/smrt co-repressor, allowing transcriptional activation to occur [89, 93] . for vdr, 1α,25-dihydroxyvitamin d3 (1,25(oh)2d3), which is the active form of vitamin d3 (hereafter referred to as vitamin d), acts as a ligand and activates functional vdr, which then recognizes and binds to vitamin d response elements (vdres) located in the promoter region of target genes to control the transcription of those genes [94] . vdr signaling activation during infection leads to innate immune signals for the production of antimicrobial peptides (amps), such as human cathelicidin amp (camp) and β-defensin 2, which are important in coordinating vitamin d-induced antimicrobial responses [95] . ppars include three different isotypes: pparα, pparβ/δ (ppard; nr1c2), and pparγ. each isoform has a different distribution and ligands [96] . they are activated after the binding of endogenous ligands, such as fatty acids and their derivatives, or synthetic modulators, such as gw7647 and gw501516, to the ligand-binding domain. ppars form heterodimers with rxr, which, after ligand binding, results in the transactivation or repression of target genes through ppar responsive elements (ppres) [96, 97] . lxrs are the nrs which bind oxidized cholesterol derivatives such as oxysterols and intermediates of the cholesterol biosynthesis pathway [98] . the modulation of gene expression by lxr involves direct activation, repression, and transrepression [99] , and exhibits anti-inflammatory properties, as well as antimicrobial effects [98] . class iii and iv receptors include the dimeric and monomeric orphan receptors, respectively. errα, one of the orphan nuclear receptors, is not regulated by the presence of natural ligands, but is regulated by post-transcriptional modifications, such as phosphorylation, sumoylation, or acetylation of the n-terminal domain [23, 100] , and is essential for antimicrobial host defense [23] . other members of orphan nr include retinoic acid-related orphan receptors (ror), whereas fxr and rev-erb have been classified as adopted orphan receptors [92] . in addition, nrs are important in the regulation of autophagy [17, 20, 27, 101] , not only at the level of the transcription of atgs, but also at the post-transcriptional level, by regulating protein-protein interactions, post-translational modification, and epigenetic mechanisms [21] [22] [23] 76, 102] . the contributions of nr modulation to defense against pathogens are beginning to be deciphered. here, we focus on the roles of vdr, er, err, and ppar in autophagic host defense against infection and discuss other nrs as links between autophagy and innate immunity during infection ( figure 2) . a deeper understanding of nr signaling and its underlying mechanisms will facilitate the development of autophagy-based host-directed anti-infectives. cells 2020, 9, 1979 5 of 28 and its underlying mechanisms will facilitate the development of autophagy-based host-directed anti-infectives. have been shown to play critical functions in the regulation of autophagy-mediated host defensive immune responses during infection. these nrs regulate and participate in the autophagic signaling pathways not only at the transcriptional level, but also at the post-transcriptional level. vdr is one of the best characterized nrs related to autophagic function against various infections. it is well-known that vdr signaling increases autophagy activation via the induction of cathelicidin, which is a small cationic antimicrobial peptide. in addition, vdrs functionally link adaptive and innate immune responses by regulating downstream pathways of autophagy. er activates autophagy by increasing reactive oxygen species (ros) generation and akt/ mammalian target of rapamycin (mtor) signaling. errs, which are one of the orphan family members of nr, also regulate a variety of cellular responses, including autophagy. the induction of pgc-1α upregulates the errα to promote mitophagy and an antimicrobial effect through sirtuin 1. pparα activation leads to the expression of transcription factor eb (tfeb) and its nuclear translocation, resulting in the enhancement of lysosomal biogenesis. pparβ/δ prevents harmful er stress by increasing autophagy markers beclin-1 and lc3 ii. vdr signaling ameliorates infection and inflammation [66, 67, 103, 104] . studies on the role of vitamin d in innate immunity have revealed that autophagy enhances phagosomal maturation and lysosomal function, and ameliorates inflammation and antimicrobial protein generation [67, 105, 106] . a physiological level of the active form of vitamin d (1α,25-dihydroxycholecalciferol) or functional activation of vdr signaling promotes autophagy activation in human monocytes or monocytic cells by inducing the synthesis of cathelicidin-a cationic antimicrobial peptide-which promotes phagosomal maturation in the presence of intracellular mtb [107] [108] [109] or mycobacterium marinum figure 2 . schematic representation of the signaling pathways of nuclear receptors (nrs) in autophagy-mediated host defense. nrs, including the vitamin d receptor (vdr), estrogen receptor (er), estrogen-related receptors (errs), and peroxisome proliferator-activated receptors (ppars) have been shown to play critical functions in the regulation of autophagy-mediated host defensive immune responses during infection. these nrs regulate and participate in the autophagic signaling pathways not only at the transcriptional level, but also at the post-transcriptional level. vdr is one of the best characterized nrs related to autophagic function against various infections. it is well-known that vdr signaling increases autophagy activation via the induction of cathelicidin, which is a small cationic antimicrobial peptide. in addition, vdrs functionally link adaptive and innate immune responses by regulating downstream pathways of autophagy. er activates autophagy by increasing reactive oxygen species (ros) generation and akt/ mammalian target of rapamycin (mtor) signaling. errs, which are one of the orphan family members of nr, also regulate a variety of cellular responses, including autophagy. the induction of pgc-1α upregulates the errα to promote mitophagy and an antimicrobial effect through sirtuin 1. pparα activation leads to the expression of transcription factor eb (tfeb) and its nuclear translocation, resulting in the enhancement of lysosomal biogenesis. pparβ/δ prevents harmful er stress by increasing autophagy markers beclin-1 and lc3 ii. vdr signaling ameliorates infection and inflammation [66, 67, 103, 104] . studies on the role of vitamin d in innate immunity have revealed that autophagy enhances phagosomal maturation and lysosomal function, and ameliorates inflammation and antimicrobial protein generation [67, 105, 106] . a physiological level of the active form of vitamin d (1α,25-dihydroxycholecalciferol) or functional activation of vdr signaling promotes autophagy activation in human monocytes or monocytic cells by inducing the synthesis of cathelicidin-a cationic antimicrobial peptide-which promotes phagosomal maturation in the presence of intracellular mtb [107] [108] [109] or mycobacterium marinum [110] . in addition, vitamin d treatment and tlr8-mediated vdr signaling activation enhanced autophagy in human macrophages in a manner dependent on the atg5 and beclin-1, thereby inhibiting human immunodeficiency virus (hiv)-1 replication or the co-infection of hiv and mtb [111] [112] [113] . vitamin d-mediated autophagy and cathelicidin expression are negatively regulated by prostaglandin (pg)e2-an arachidonic acid-derived lipid mediator-via e prostanoid (ep)2 and ep4 receptors [114] . vitamin d supplementation in mice significantly induced vdr, cathelin-related antimicrobial peptide (cramp), and lc3b expression, but decreased the collagenase matrix metalloproteinase-1 [115] . a structural equation modeling analysis suggested that vitamin d-mediated autophagy reduces necrosis [115] . additionally, clinical trials of vitamin d as adjunctive therapy to standard anti-tuberculosis (tb) treatment showed a significant decline in intracellular mtb growth and the levels of proinflammatory cytokines/chemokines [116, 117] , but no clear effect on long-term sputum-smear conversion [118] . these data suggest that the vitamin d-autophagy pathway is associated with clinical recovery from tb. nevertheless, further studies are needed to determine the effects and risks of vitamin d adjunctive therapy, as discussed by others [95, 119, 120] . we limit the discussion in this review to clinical trials of vitamin d therapy in tb and other infectious diseases. ifn-γ, which is an important cytokine in the adaptive th1 immune response, alone [121] or in combination with the cd40 ligand [122] , enhanced vdr-mediated antimicrobial defense in human monocytes/macrophages in vitamin d-sufficient serum. vitamin d treatment was required for the expression of il-12 [123] , and the combination of il-12 and il-18 in human macrophages enhanced the cell-autonomous production of ifn-γ and the autophagy-cathelicidin pathway, which upregulated the antimicrobial response to mtb [124] . therefore, functional vdr signaling links the adaptive and innate immune responses by regulating autophagy, phagosome-lysosome fusion, and cytokine production in mtb infection. vitamin d treatment reversed the influenza a virus-induced inhibition of autophagic flux by inducing the expression of syntaxin-17 and the v-type proton atpase subunit (atp6v0a2) [125] . in addition, probiotic lactic-acid bacteria isolated from kimchi activated vdr-autophagy responses and enhanced the expression of atg16l1 and beclin-1, resulting in an anti-inflammatory and anti-infective effect in the intestines [126] . vitamin d treatment restored the lysosomal function impaired by helicobacter pylori in gastric epithelial cells, by activating-protein disulfide isomerase family a member 3 (pdia3) receptor and upregulating mucolipin-3 (mcoln3)-mediated ca 2+ release [106] . in an animal study of aspergillus fumigatus infection, vitamin d treatment led to autophagic homeostasis by reducing the number of autophagy-mediated lysosomes and regulatory t-cells, thus enhancing the antimicrobial response [127] . moreover, vitamin d suppressed rotavirus infection by upregulating the autophagy gene beclin-1 and promoting autophagic maturation and cathelicidin gene expression [128] . although vitamin d-induced autophagy is critical for an effective immune response, further studies are needed to determine the ability of vitamin d to prevent and treat infectious diseases in humans. the studies on vdr-related autophagy during infection are summarized in table 1 . estrogen-a female sex steroid hormone-and its receptors (erα and erβ) reportedly modulate autophagy, which is implicated in various human diseases and the determination of cell fate [21, 129] . indeed, ers and the downstream genomic and non-genomic signaling cascades affect the outcomes of tumorigenesis and angiogenesis in breast cancer [21, 130] . in addition, erα activation by estrogen enhances autophagy and tumor cell survival in papillary thyroid cancer by promoting reactive oxygen species (ros) generation and the activation of extracellular signal-regulated kinases [131] . estrogen modulators influence antimicrobial responses by influencing autophagy. the selective er modulator bazedoxifene suppresses the intracellular growth of mtb by activating autophagy via ros generation and akt/ mammalian target of rapamycin (mtor) signaling [90] . tamoxifen (tam) is a potent inhibitor of shiga toxin trafficking and toxicity in a manner independent on ers [132] . tam also restricted toxoplasma replication by inducing xenophagy or autophagy [133] . long-term treatment with 17β-estradiol (e2) exerted a beneficial effect on endotoxemia-associated circulatory and multiple organ dysfunction in ovariectomized rats, which was mediated, at least in part, by autophagy activation [134] . clarification of the mechanisms through which ers modulate autophagy and/or host defense, as well as the crosstalk between autophagy and immunity in the context of er signaling, is needed for the development of novel therapeutic modalities for infection and inflammation. errs are orphan members of the nr family, and are involved in a variety of biological responses, including cellular metabolism and energy control [135] [136] [137] . errα is a critical regulator of autophagy at transcriptional and post-translational levels, particularly in cooperation with sirtuin 1. these effects promoted the antimicrobial response to mtb [23] . the thyroid hormone upregulated the expression of errα by inducing pgc-1α (ppargc1a), thus modulating mitochondrial biogenesis and mitophagy. mechanistically, the thyroid hormone upregulated the autophagy-regulating kinase ulk1 through errα, which was required for the autophagic clearance of mitochondria, i.e., mitophagy [138] . in contrast, the inhibition of errα activity by the inverse agonist xct790 induced autophagy and promoted the clearance of toxic protein aggregates, enhancing its neuroprotective effect [139] . there is a role for errα in host defense between intracellular bacteria and viruses [23, [140] [141] [142] . therefore, future studies should clarify the role of errα in modulating autophagy and evaluate its therapeutic potential as an antimicrobial. the studies on ers and errα-related autophagy during infection are summarized in table 2 . ptc, papillary thyroid carcinoma; mcf-7, breast cancer cell line; erk1/2, extracellular signal-regulated protein kinase; mtor, mammalian target of rapamycin; aicar, 5-aminoimidazole-4-carboxamide ribonucleotide; bmdm, bone marrow-derived macrophages; sirt1, sirtuin 1; ppargc1a, peroxisome proliferator-activated receptor gamma coactivator 1-alpha; ulk1, unc-51 like autophagy activating kinase. the nutrient-sensing nrs, pparα and fxr, play reciprocal functions in the regulation of autophagy; pparα enhances and fxr suppresses autophagy to enhance lipolysis [22] and ciliogenesis [143] . pparα ameliorates inflammatory and injurious conditions by inducing autophagy in various cells and tissues [144, 145] . in addition, autophagy activation leads to pparα activation by degrading nuclear receptor co-repressor 1 (ncor1), which interacts with and suppresses the transactivation of pparα [146] . pparα modulates antimicrobial responses to mtb, mycobacterium bovis bacillus calmette-guérin (bcg), or mycobacterium abscessus by activating transcription factor eb (tfeb) [70] [71] [72] . in addition, pparα deficiency resulted in an exaggerated inflammatory response to mycobacterial infection. importantly, pparα activation significantly reduced the lipid body number and size in macrophages infected with mtb or m. bovis bcg, suggesting that pparα contributes to lipid catabolism and reduces the foamy refuge during mycobacterial infection [72] . tfeb controlled the inflammatory response of host macrophages to mtb or bcg infection [72] . however, tfeb was reportedly required for the induction of inflammatory cytokines and chemokines in macrophages infected with staphylococcus aureus [147] . numerous agents have been reported to activate pparα and enhance tfeb, thereby promoting lysosomal biogenesis in models of chronic inflammatory and degenerative diseases [148] [149] [150] [151] . therefore, pparα-activating drugs have potential for various infectious diseases. hiv infection inhibited autophagy in macrophages, promoting the intracellular survival of mtb and non-tuberculous mycobacteria (ntm) [152] . trehalose, which targets tfeb and pgc-1α [153] , activated the xenophagic flux to eradicate intracellular mtb and ntm [152] . mechanistically, trehalose enhanced tfeb nuclear translocation and autophagy activation in an mucolipin 1 (mcoln1)-dependent manner [152] . because trehalose promotes the functionally active conformation of the n-terminal domain of the glucocorticoid receptor [154] , its antimicrobial effect may be mediated by gr signaling. therefore, trehalose-induced autophagy may be involved in controlling co-morbidities of hiv and tb infections. pparβ/δ inhibits the er stress induced by palmitate in ac16 cardiomyocytes by inducing expression of the autophagy markers beclin-1 and lc3 ii, thus preventing the harmful cardiac effects of er stress [155] . the treatment of septic mice with the pparβ/δ-agonist gw0742 improved long-term survival and protected against multiple organ injury and dysfunction by modulating inflammatory signaling and coagulation [156, 157] . amodiaquine, which is a selective anti-plasmodium falciparum agent, suppresses autophagolysosomal degradation and pparγ activity [158] . the pparγ ligand hp24, which is a pyridinecarboxylic acid derivative, ameliorated the pathologic and inflammatory responses induced by trypanosoma cruzi [159] . int131, which is a novel non-thiazolidinedione and selective pparγ modulator, has a beneficial anti-inflammatory effect on ecohiv-infected glial cells and in a mouse model of ecohiv infection [160] . however, whether pparβ/δ or pparγ activation exerts an antimicrobial effect by modulating autophagy is unclear. further studies are needed to clarify the roles of pparβ/δ and pparγ in controlling the host response to infections in the context of autophagy activation. the studies on ppar-related autophagy during infection are summarized in table 3 . tfeb, transcription factor eb; enos, endothelial nos; vegf-a, vascular endothelial growth factor a; nf-κb, nuclear factor kappa-light-chain-enhancer of activated b cells. the adopted orphan nr-rev-erbα-is involved in adipogenesis, muscle differentiation, glucose/lipid metabolism, and the circadian rhythm [161] [162] [163] . rev-erbα links the circadian rhythm and autophagy, and directly regulates the rhythmic expression of atgs in zebrafish [164] . the key transcriptional regulators tfeb and tfe3 are required for the expression of rev-erbα [162] , suggesting another link between autophagy and the circadian cycle. during infection, rev-erbα activation by gsk4112 exerted an anti-mycobacterial effect in macrophages by enhancing autophagy and lysosomal biogenesis and suppressing il-10 synthesis [165] . however, the pharmacological activation of rev-erbα and rev-erbβ (nr1d2) using agonists inhibited autophagy and lipogenesis, thereby exerting an anticancer effect [163] . moreover, the lysosomotropic rev-erbβ ligand (arn5187) inhibited autophagy and exerted a cytotoxic effect in breast cancer cells [166] . the over-expression of rev-erbα in skeletal muscle induced mitochondrial activity and respiratory capacity, but repressed autophagy [167] . therefore, rev-erbα and rev-erbβ may play diverse roles in autophagy regulation, depending on the cell type and pathological status. because the circadian rhythm may be linked to the immune response to infection [168] [169] [170] , further studies should clarify the roles of rev-erbα and rev-erbβ in autophagy, the circadian rhythm, and the immune response to bacterial and fungal pathogens. all-trans retinoic acid and/or arsenic trioxide induced autophagy of the oncoprotein promyelocytic leukemia (pml)/rara, suggesting rarα as a therapeutic target for acute pml [171, 172] . in addition, rarα activated autophagy in human primary b cells [173] and various types of cancer cells [174, 175] . the downregulation of rarα led to the upregulation of vdr expression in acute myeloid leukemia cells [176] . however, its role in autophagy during the antimicrobial response is unclear. rarα is reportedly a critical regulator of the maturation of monocyte-derived dendritic cells during hiv infection [177] , although its relevance to autophagy has not been evaluated. similarly, little is known about the role of rarβ in the regulation of autophagy during infection. rarβ has a tumor suppressive function and is involved in cell differentiation and apoptosis. interestingly, the human papillomavirus type 16 (hpv16) e7 oncoprotein upregulated the mrna and protein levels of rarβ in cervical cancer cells and in the cervix of k14e7 transgenic mice [178] . during human adenovirus infection, the rarβ mrna and protein levels were downregulated, but the overexpression of rarβ decreased human adenovirus production [179] . therefore, rarβ may have therapeutic effects for adenovirus infection, although the autophagy-mediated suppression of infection is unclear in rarβ-induced antiviral and anticancer effects. rors are important in the regulation of the circadian clock, metabolic homeostasis, and tumorigenesis [180, 181] . although rors are emerging as therapeutic targets for tumors, their roles in the modulation of host defense during infection in the context of autophagy are unclear. upon infection with highly pathogenic avian influenza viruses (hpaiv h5n1), rorα is synthesized and suppresses nf-κb signaling and the inflammatory response in monocytes, thereby contributing to the escape of h5n1 from the host inflammatory defenses [182] . rorα is a melatonin receptor and protects against ischemic heart injury and diabetic cardiomyopathy [183, 184] . the effect of melatonin on autophagy regulation has been reported in various normal and cancer cells [185, 186] . in addition, the protective effects of melatonin in various bacterial, viral, and parasitic infections have been characterized [187] [188] [189] [190] [191] . melatonin treatment of hodgkin lymphoma cells increased the expression of rorα, rorβ, and rorγ, and enhanced autophagy activation [192] . therefore, it would be interesting to investigate the involvement of rors in melatonin-mediated autophagy activation. as a nutrient-sensing and autophagy-regulating nr, fxrα regulates hepatic autophagy to maintain the energy balance in the liver [22, 193] and inhibits autophagy-mediated ciliogenesis [143] . the inhibitory effect of fxrα is counteracted by pparα, which activates autophagy [22, 143, 193] . because pparα is involved in the coordination of autophagy activation and antimicrobial defenses [72] , it would be interesting to investigate the role of fxrα. in a model of cholestasis, the activation of autophagy maturation is inhibited in an fxr-dependent manner, partly as a result of the induction of rubicon. however, ursodeoxycholic acid (udca), which is a non-fxr-agonistic bile acid, induced hepatic autophagy and reduced the expression of rubicon, which is an inhibitor of autophagy [194] . in an autophagy-deficient liver, the expression of fxr and its downstream genes was inhibited, promoting cholestatic injury [195] . therefore, the link between fxr and autophagy requires further investigation. lxrα and lxrβ are negative regulators of cholesterol metabolism and inflammation [196, 197] . both lxrs are important in the antimicrobial response to viral and bacterial infections [75] . three synthetic lxr agonists (t0901317, gw3965, and lxr-623) had a long-lasting inhibitory effect on hepatitis b virus replication and gene expression [198] . in addition, both lxrα and lxrβ were required for the suppression of gammaherpesvirus reactivation by downregulating fatty acid and cholesterol synthesis in macrophages [199] , and for the inhibition of herpes simplex virus type 1 (hsv-1) by 25-hydroxycholesterol [200] . il-36 and lxr signaling promoted anti-mycobacterial effects by inducing the expression of cholesterol-converting enzymes and regulating the expression of antimicrobial peptides [201] . in addition, lxr activation inhibited salmonella infection by inducing the expression of the multifunctional enzyme cd38 [202] . lxrs are involved in the regulation of autophagy in various pathological conditions, including cancers [203, 204] . therefore, further studies on the involvement of lxrs in modulating autophagy during infection with intracellular microbes are required. the thyroid hormone is a regulator of the metabolic rate, oxidative phosphorylation (oxphos), and ros production [205, 206] , and a potent inducer of autophagy/mitophagy [207, 208] . thyroid hormone suppresses the hepatic carcinogenesis induced by the hbv x protein by promoting mitochondrial turnover via autophagy activation. in addition, thyroid hormone/tr-induced hepatic pink1 expression is associated with hepatic cellular carcinoma (hcc) progression and a poor prognosis [209] . one might expect that thyroid hormone is involved in the modulation of host antimicrobial responses through autophagy. however, it remains to be determined whether both trα and trβ contribute to pathogenesis or protective immunity to broader ranges of infections through autophagy modulation. the studies on several nrs with potential roles in connecting autophagy and host defense are summarized in table 4 . prevention of proper fusion of autophagolysosome with lysosomes by bile acids, through fxr-dependent induction of rubicon [194] gw4064 in vivo mice with hepatic deletion of atg7 or atg5 with or without nrf2 codeletion ↓ liver injury nrf2 activation in autophagy deficiency leading to downregulation of fxr, causing cholestasis [195] lxr t0901317, gw3965, lxr-623 hbv/primary human hepatocytes, heparg cells -anti-hbv effects inhibition of cholesterol 7α-hydroxylase 1 (cyp7a1) mrna levels [198] dda melanoma and aml cell lines, aml patients samples, in vivo mice ↑ anti-tumor dda acting as partial agonist on lrx to increase nur77, nor1, and lc3 expression [204] tr t3 hepg2, huh7 cells ↑ lipid metabolism upregulation of c19orf80 expression, which is involved in lipid metabolism through breakdown of lipid droplets [208] mice model of hepatocarcinogenesis, hepg2 cells ↑ inhibition of hepatic dna damage, inflammation, and carcinogenesis induction of hepatic pink1 expression, which ubiquitinates hbx protein to trigger mitophagy [209] cebpb, ccaat/enhancer-binding protein beta; tfeb, transcription factor eb; tfe3, transcription factor e3; lamp1, lysosomal-associated membrane protein 1; il, interleukin; lkb1, liver kinase b1; ampk, amp-activated protein kinase; dram2, dna-damage regulated autophagy modulator; pml, promyelocytic leukemia; atra, all-trans-retinoic acid; hpaiv, highly pathogenic avian influenza virus; apl, acute promyelocytic leukemia; mi/r, myocardial ischemia/reperfusion; hl, hodgkin lymphoma; rpe, retinal pigment epithelium cells; nrf2, nuclear factor erythroid 2-related factor 2; hbv, hepatitis b virus; dda, dendrogenin a; nur77, nerve growth factor ib; nor1, neuron-derived orphan receptor 1; t3, triiodothyronine; pink1, pten-induced kinase 1. given the role of autophagy in controlling intracellular pathogens, there is an urgent need for autophagy-directed therapeutics and prophylactics. the targeting of autophagy in monocytes/macrophages stimulates the innate immune response, the dampening of inflammation and suppression of innate immunity, and the promotion of pathogen escape [210] . therefore, a more comprehensive understanding of the molecular mechanisms of crosstalk between autophagy and the innate immunity system in acute vs. chronic infection by various pathogens in immunocompetent vs. immunocompromised hosts will facilitate the development of therapeutics and vaccines. nr protects against a variety of infections and modulates autophagy during pathogen invasion. early studies exploited vdr-or errα-targeted antimicrobial responses and were followed by several trials expanding the effects of other nrs. it is known that the atgs involved in non-canonical autophagy are different from those involved in canonical autophagy, but only a few studies on nr-mediated non-canonical autophagy pathways have been reported to date [211] . we are only beginning 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estrogen-related receptor alpha and gamma in metabolic control and related diseases thyroid hormone receptor and erralpha coordinately regulate mitochondrial fission, mitophagy, biogenesis, and function modulation of autophagy by a small molecule inverse agonist of erralpha is neuroprotective nuclear receptor err alpha and coactivator pgc-1 beta are effectors of ifn-gamma-induced host defense estrogen-related receptor alpha is required for efficient human cytomegalovirus replication erralpha negatively regulates type i interferon induction by inhibiting tbk1-irf3 interaction ciliogenesis is reciprocally regulated by ppara and nr1h4/fxr through controlling autophagy in vitro and in vivo peroxisome proliferator-activated receptor alpha activation attenuates the inflammatory response to protect the liver from acute failure by promoting the autophagy pathway chondroprotection of pparalpha activation by wy14643 via autophagy involving akt and erk in lps-treated mouse chondrocytes and osteoarthritis model autophagy regulates lipid metabolism through selective turnover of ncor1 innate host defense requires tfeb-mediated transcription of cytoprotective and antimicrobial genes pparalpha between aspirin and plaque clearance cinnamic acid activates pparalpha to stimulate lysosomal biogenesis and lower amyloid plaque pathology in an alzheimer's disease mouse model aspirin induces lysosomal biogenesis and attenuates amyloid plaque pathology in a mouse model of alzheimer's disease via pparalpha activation of peroxisome proliferator-activated receptor alpha induces lysosomal biogenesis in brain cells: implications for lysosomal storage disorders trehalose limits opportunistic mycobacterial survival during hiv co-infection by reversing hiv-mediated autophagy block trehalose induces autophagy via lysosomal-mediated tfeb activation in models of motoneuron degeneration trehalose induces functionally active conformation in the intrinsically disordered n-terminal domain of 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ulk1-mediated autophagy the lncrna hotairm1 regulates the degradation of pml-rara oncoprotein and myeloid cell differentiation by enhancing the autophagy pathway activation of raralpha induces autophagy in skbr3 breast cancer cells and depletion of key autophagy genes enhances atra toxicity regulation of vitamin d receptor expression by retinoic acid receptor alpha in acute myeloid leukemia cells a comprehensive map of the monocyte-derived dendritic cell transcriptional network engaged upon innate sensing of hiv human papillomavirus type 16 e7 oncoprotein upregulates the retinoic acid receptor-beta expression in cervical cancer cell lines and k14e7 transgenic mice retinoic acid receptor beta, a potential therapeutic target in the inhibition of adenovirus replication retinoic acid receptor-related orphan receptors: critical roles in tumorigenesis retinoid-related orphan receptors (rors): critical roles in development, immunity, circadian rhythm, and cellular metabolism highly pathogenic 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rorc in hodgkin lymphoma nutrient-sensing nuclear receptors pparalpha and fxr control liver energy balance fxr-dependent rubicon induction impairs autophagy in models of human cholestasis hepatic autophagy deficiency compromises farnesoid x receptor functionality and causes cholestatic injury liver x receptors regulate cholesterol metabolism and immunity in hepatic nonparenchymal cells liver x receptors bridge hepatic lipid metabolism and inflammation activation of the liver x receptor pathway inhibits hbv replication in primary human hepatocytes lxr alpha restricts gammaherpesvirus reactivation from latently infected peritoneal cells activation of liver x receptor plays a central role in antiviral actions of 25-hydroxycholesterol moura-alves, p. il-36/lxr axis modulates cholesterol metabolism and immune defense to mycobacterium tuberculosis the nuclear receptor lxr limits bacterial infection of host macrophages through a mechanism that impacts cellular nad metabolism ligand-dependent transcriptional induction of lethal autophagy: a new perspective for cancer treatment dendrogenin a drives lxr to trigger lethal autophagy in cancers thyroid hormone induction of mitochondrial activity is coupled to mitophagy via ros-ampk-ulk1 signaling thyroid hormones and mitochondria: with a brief look at derivatives and analogues thyroid hormone stimulates hepatic lipid catabolism via activation of autophagy chromosome 19 open reading frame 80 is upregulated by thyroid hormone and modulates autophagy and lipid metabolism thyroid hormone protects hepatocytes from hbx-induced carcinogenesis by enhancing mitochondrial turnover targeting autophagy in innate immune cells: angel or demon during infection and vaccination? front estrogen receptor alpha regulates non-canonical autophagy that provides stress resistance to neuroblastoma and breast cancer cells and involves bag3 function we are indebted to current and past members of our medical research center (i-mrc) for discussions and investigations that contributed to this article. we apologize to colleagues whose work and publications could not be referenced owing to space constraints. the authors declare no conflict of interest. key: cord-276483-4yp4beuh authors: cooper, isabella d; crofts, catherine a p; dinicolantonio, james j; malhotra, aseem; elliott, bradley; kyriakidou, yvoni; brookler, kenneth h title: relationships between hyperinsulinaemia, magnesium, vitamin d, thrombosis and covid-19: rationale for clinical management date: 2020-09-16 journal: open heart doi: 10.1136/openhrt-2020-001356 sha: doc_id: 276483 cord_uid: 4yp4beuh risk factors for covid-19 patients with poorer outcomes include pre-existing conditions: obesity, type 2 diabetes mellitus, cardiovascular disease (cvd), heart failure, hypertension, low oxygen saturation capacity, cancer, elevated: ferritin, c reactive protein (crp) and d-dimer. a common denominator, hyperinsulinaemia, provides a plausible mechanism of action, underlying cvd, hypertension and strokes, all conditions typified with thrombi. the underlying science provides a theoretical management algorithm for the frontline practitioners. vitamin d activation requires magnesium. hyperinsulinaemia promotes: magnesium depletion via increased renal excretion, reduced intracellular levels, lowers vitamin d status via sequestration into adipocytes and hydroxylation activation inhibition. hyperinsulinaemia mediates thrombi development via: fibrinolysis inhibition, anticoagulation production dysregulation, increasing reactive oxygen species, decreased antioxidant capacity via nicotinamide adenine dinucleotide depletion, haem oxidation and catabolism, producing carbon monoxide, increasing deep vein thrombosis risk and pulmonary emboli. increased haem-synthesis demand upregulates carbon dioxide production, decreasing oxygen saturation capacity. hyperinsulinaemia decreases cholesterol sulfurylation to cholesterol sulfate, as low vitamin d regulation due to magnesium depletion and/or vitamin d sequestration and/or diminished activation capacity decreases sulfotransferase enzyme sult2b1b activity, consequently decreasing plasma membrane negative charge between red blood cells, platelets and endothelial cells, thus increasing agglutination and thrombosis. patients with covid-19 admitted with hyperglycaemia and/or hyperinsulinaemia should be placed on a restricted refined carbohydrate diet, with limited use of intravenous dextrose solutions. degree/level of restriction is determined by serial testing of blood glucose, insulin and ketones. supplemental magnesium, vitamin d and zinc should be administered. by implementing refined carbohydrate restriction, three primary risk factors, hyperinsulinaemia, hyperglycaemia and hypertension, that increase inflammation, coagulation and thrombosis risk are rapidly managed. individuals most at risk of poorer outcomes from sars-cov-2 infection causing covid-19 include those ≥65 years of age and/or those with pre-existing conditions such as: obesity, type 2 diabetes mellitus (t2dm) or elevated d-dimer 1 2 and black, asian and minority ethnic (bame) individuals. 1 3 a common denominator of these presentations, hyperinsulinaemia, has an explanation by the underlying science that provides the theory for our proposed management algorithm for frontline practitioners. there is a clear correlation between increasing age and increasing prevalence of metabolic disease including hypertension, stroke, t2dm, cvd and cancer occurrences. yet this correlation is not causation. those conditions, traditionally known as 'diseases of ageing', are occurring at higher rates in younger population groups. 2 4 chronic hyperinsulinaemia provides a plausible mechanism of action underlying the increase in these morbidities. 5 this mechanism may also help to explain why these individuals have poorer outcomes associated with sars-cov-2 infections. hyperglycaemia increases secretion of proinflammatory cytokine interleukin 6 (il-6) and blood coagulation via increasing hepatic clotting factors. conversely, hyperinsulinaemia disturbs fibrinolysis by elevating plasminogen activator inhibitor type 1 (pai-1). 6 7 increased thrombi/emboli have been detected in postmortem findings in covid-19 cases. [8] [9] [10] [11] [12] in fact, pulmonary thrombi may be the cause of oxygen desaturation and acute respiratory distress in many covid-19 cases. thus, strategies that can reduce the risk of disseminated intravascular coagulopathy may improve oxygenation and outcomes in covid-19. 13 14 underlying science for rationale of proposed clinical management hyperglycaemia increases haemoglobin glycation damage. 15 16 a study published in diabetes research and clinical practice analysed 132 patients with covid-19, classified into three groups based on haemoglobin a1c (hba1c) levels; results found a significant linear negative correlation between haemoglobin oxygen saturation (sao 2 )and hba1c, p=0.01. 16 hyperinsulinaemia inhibits beta-oxidation and ketolysis, thereby 'enforcing' cellular atp generation from glucose substrate. 17 glucose oxidation consumes four nicotinamide adenine dinucleotide (nad+) to produce two acetyl moieties, whereas beta-oxidation consumes two, ketolysis one and acetoacetate none (online supplemental appendix a); consequently, glucose oxidation depletes the nad+ intracellular pool more than the other three substrates combined, thereby decreasing nad+ availability for mitochondrial deacetylase sirtuin 3 (sirt3) activity. 18 19 nad+ dependent sirt3 activates manganese superoxide dismutase 2 (mnsod2) via acetylation of lysine residue 68 (k68) and increases the production of nadph via isocitrate dehydrogenase (idh2) to drive the reduction of oxidised glutathione (gssg) to reduced glutathione (gsh). coupled with the glucose fuelling effect on the cellular redox system, insulin increases mitochondrial production of reactive oxygen species (ros) via generation of ceramides. 20 hyperglycaemia and hyperinsulinaemia are the twin blades of dysregulated ros production and management (figure 1). the haem part of haemoglobin is synthesised in mitochondria. as a result of increased haemoglobin glycation and intracellular haem oxidative damage, an upregulated demand for synthesis of new haem to keep up the replenishment of damaged haem ensues. this may contribute to respiration independent increased carbon dioxide levels, as extramitochondrial haem synthesis step 5, produces four carbon dioxide molecules via the decarboxylation of uroporphyrinogen iii to coproporphyrinogen iii, further taxing the external respiration system. in addition, step 7 of haem synthesis generates the production of three hydrogen peroxide (h 2 o 2 ) ros molecules. thus, increased haem damage that would necessitate an increased upregulation in haem synthesis may place further burden on the intracellular redox figure 1 schematic representation of the role of hyperinsulinaemia in endothelial/vascular inflammation, red blood cell (rbc) and platelet coagulation, sequestration and/or inhibition of vitamin d activation and its downstream consequences, such as decreased cholesterol sulfate (ch-s), heparan sulfate proteoglycans (hspg) and cathelicidin synthesis. carbon dioxide (co 2 ), carbon monoxide (co), deep vein thrombosis (dvt), endothelial nitric oxide synthase (enos), reduced glutathione (gsh), oxidised glutathione (gssg), haemoglobin a1c (hba1c), haem-oxygenase (ho), manganese superoxide dismutase 2 (mnsod2), nicotinamide adenine dinucleotide (nad+), plasma membrane (pm), plasminogen activator inhibitor type 1 (pai-1), pulmonary embolism (pe), reactive oxygen species (ros), oxygen saturation (spo2), sirtuin 3 (sirt3) and type 2 diabetes mellitus (t2dm). health care delivery, economics and global health care system. to compound the problem, mitochondrial electron transport chain (etc) complexes, complex ii and iii require haem b (protoheme ix). hyperglycaemia and hyperinsulinaemia increased intracellular ros production coupled with diminished mitochondrial stress management capacity, increases mitochondrial oxidative phosphorylation (mt-oxphos) haem oxidation, reducing mt-oxphos capacity. 21 the breakdown of damaged haem activates signals for the synthesis of new haem. haem-oxygenase (ho) induces hepatic aminolevulinic acid synthase (alas1) (enzyme in the first step of haem synthesis) activity. haem is catabolised/degraded by ho (gene hmox1/ hmox2), producing ferrous iron, biliverdin and carbon monoxide, resulting in increased plasma ferritin and bilirubin. these markers have been shown to be significantly elevated in covid-19 patients with poorer outcomes. 22 increased haem breakdown by ho produces endogenous carbon monoxide, which has a higher binding affinity with haemoglobin compared with oxygen. this would result in a decreased oxygen saturation capacity. deep vein thrombosis occurrence increases significantly with elevated carbon monoxide concentrations, increasing the risk of pulmonary emboli (pe) and acute coronary syndrome. 23 24 hyperinsulinaemia drives the pathogenesis of obesity, cvd, t2dm, hypertension, increased haem oxidation, haem breakdown, endogenous carbon monoxide production and resultant increased thrombi risk. furthermore, d-dimer found to be markedly elevated in patients with covid-19 is a direct marker for fibrinolytic and coagulation activity. 25 26 patients with covid-19 who have a high risk of venous thromboembolisms suffer poorer outcomes. 22 measuring carboxyhaemoglobin (cohb or hbco) to assess carbon monoxide levels in covid-19 positive patients is warranted and may provide further insight. vitamin d status has garnered great interest and debate with regards to risk/prevention of infection and prognosis in those with covid-19. 1 27 28 evidence supports the argument that good levels of vitamin d status lowers the risk of contracting a respiratory infectious pathogen, 29 possibly due to vitamin d induced increases in airway surface liquid epithelial production of antimicrobial and immunomodulatory host defence peptide, cathelicidin. [30] [31] [32] in a retrospective study of 107 patients in switzerland, results showed 25-hydroxycholecalciferol d-calcidiol (25ohd, inactive d3) levels were significantly lower in patients that had a positive pcr for sars-cov-2, median value 11.1 ng/ml versus covid-19 negative patients, who had significantly higher 25ohd levels at 24.6 ng/ ml, p=0.004. this study indicates vitamin d's role in association with risk of infection, as opposed to disease severity and/or mortality, supporting an antiviral role for vitamin d3. 33 furthermore, a study published in the irish medical journal found increased rates of vitamin d3 deficiency in lower latitude countries such as spain and italy, despite being typically sunnier. the authors attribute this to fortification and supplementation practices in their more northern european neighbours, as well as darker skin pigmentation and sun avoidance in southern warmer climate inhabitants. 34 epidemic acute respiratory infections result from a lack of sunlight exposuregenerated vitamin d during winter and early spring; this most likely includes viral respiratory infection covid-19. 35 cannell et al 35 demonstrated that groups low in vitamin d levels, including: obese, elderly, hyperinsulinaemic, dark skin and those with chronic health conditions, required 5000 iu of vitamin d each day in order to obtain 125 nmol/l (50 ng/ml) plasma levels of 25ohd that appears to be protective against viral respiratory infection and sequalae. further investigations into the relationship between vitamin d levels, age and covid-19 outcomes would be valuable. a 2017 meta-analysis of 25 randomised controlled trials (rcts) published in the bmj, studying 11 000 participants given vitamin d or placebo, concluded that vitamin d supplementation is safe and protects against acute respiratory tract infections, where the greatest benefit was seen in those most deficient and benefits were also greatest in subjects taking vitamin d daily. 36 the study highlighted that only four people who are deficient in vitamin d need to be treated to prevent one case of acute infection. additionally, critical care research has demonstrated the efficacy and importance of vitamin d contribution to survival in intensive care unit (icu) patients with acute respiratory distress syndrome. 37 vitamin d operates by several mechanisms that are critical in immune defence, those include: maintenance of tight junctions, promotes the production of antimicrobial peptides cathelicidin and defensins in airway epithelia and macrophages 31 and moderates the inflammatory response. 38 the hotly debated question is: is a low vitamin d status a marker or maker of poor health? a low vitamin d status is associated with hyperinsulinaemia's pathologies (obesity, t2dm, cvd and metabolic cancers). 39 insulin mediates de novo lipogenesis and adipogenesis. 40 hyperinsulinaemia sequesters lipophilic vitamin d3 into adipocytes. 41 insulin stimulates bone resorption and calcium (ca 2+ ) and phosphate release. elevated plasma ca 2+ and phosphate inhibits renal enzymatic 25ohd-1α-hydroxylation (cyp27b1) activation of inactive 25ohd-calcidiol to biologically active 1,25(oh)2d-calcitriol. 42 cyp27b1 is a mitochondrial cytochrome p450 hydroxylase situated on the matrix side of the inner mitochondrial membrane. cyp27b1 function is dependent on oxphos nadph production and healthy robust mitochondrial electron transport machinery. hyperglycaemia and hyperinsulinaemia both increase mitochondrial ros (mtros) production while decreasing ros management capacity via depletion of nad+, resulting in diminished mnsod2 and a decreased gsh:gssg ratio. 19 43-47 a decreased ability to hydroxylate and thus activate 25ohd-calcidiol to its active form 1,25(oh)2d-calcitriol, due to poor etc health and diminished nadph generation, may complicate research findings in plasma measurements that typically measure total 25ohd-calcidiol. additionally, it does not take into account vitamin d binding protein bound 25ohd-calcidiol. furthermore, some hydroxylation of inactive to active vitamin d occurs intracellularly within other tissues and may be inhibited by excessive mitochondrial ros and nad+ glucose metabolism depletion. this aspect of vitamin d metabolism may not be picked up with blood plasma measurements, where plasma total inactive 25ohd is the typical form of measure. 42 interestingly, in a year-long weight loss intervention study, 56 obese (body mass index >30 kg/m 2 ) participants were randomised to a very low carbohydrate ketogenic diet (vlckd) or a standard hypocaloric mediterranean diet (shmd). both groups had significant increases in their serum 25ohd-calcidiol status with weight loss, as measured by chemiluminescence. however, the vlckd group had a greater significant increase relative to the shmd, from 18.4 to 29.3 ng/ml, p<0.0001 versus 17.5 to 21.3 ng/ml, p=0.067, as well as decreases in c reactive protein. 48 these results indicate the role of dietary macronutrient distribution on insulin secretion stimulus and its consequential effect on mitochondrial vitamin d hydroxylation activity and possible inflammation mediated depletion (usage) of vitamin d. vitamin d may be created in the skin via exposure to ultraviolet b (uvb) radiation from sunlight and consumed in the diet. the action spectrum for vitamin d generation is uvb 280-320 nm. the best time of sun exposure for optimal vitamin d generation from sunlight, at minimal risk of cutaneous malignant melanoma, is noon. 49 other less investigated aspects of the role of vitamin d, sun exposure and blood coagulability may play a crucial role in the increased risk of poorer outcomes seen in covid-19 high-risk individuals, whose risk factors are arguably markers of hyperinsulinaemia. years of hyperinsulinaemia that would manifest overt pathologies such as obesity, cvd, hypertension and cancer would come with an already heavy-risk burden list, which includes: increased haemoglobin glycation damage, intracellular haem-oxidation with reduced antioxidative capacity, increased haem-oxygenase haem catabolism thus producing increased endogenous carbon monoxide production, leading to increased risk of dvt and subsequent pe and decreased mitochondrial vitamin d hydroxylase activation. sunlight exposure driven photo-catalyses has potential effects on other less investigated roles in human health. one is in aiding in production of cholesterol sulfate (ch-s). the majority of ch-s is synthesised in the epidermis and supplied to the bloodstream. ch-s constitutes the majority of blood sterol sulfates, having an ionic negative charge that imparts its amphiphilic property, enabling water solubility and free movement through intracellular cytoplasm and extracellular plasma. red blood cells (rbcs) and platelets produce ch-s that aids in maintaining their extracellular side plasma membrane negative charge, thus preventing thrombi and agglutination via maintaining electrorepulsion-driven dispersion. 50 endothelial cells also synthesise ch-s; the enzyme endothelial nitric oxide synthase (enos) is traditionally thought to mediate synthesis of nitric oxide (no); however, it has been established that when enos is membrane bound, it is no longer able to synthesise no. [51] [52] [53] [54] membranebound enos lacks association with intracellular calmodulin binding; this results in a closed conformation of the heterodimer enzyme. the closed conformation of enos has the potential to simultaneously transfer two electrons versus the open conformation that transfers one electron. extracellular exclusion zone water is sensitive to sunlight's infrared 270 nm spectrum. at this frequency, sunlight exposure elevates electrons to a higher excitation level, facilitating activation of the water involved in the oxidation of thiosulfate to sulfate, the first step in producing the sulfate required for ch-s synthesis. 55 56 impaired zinc utilisation and deficiency is associated with t2dm and cvd. 57 the catalytic activity of enos is zinc dependent, a deficiency in zinc would result in inhibition of enos sulfate synthesis and inhibition of enos may result in increased clotting. 58 following enos sulfate synthesis, sulfotransferase enzyme sult2b1b catalyses cholesterol sulfurylation, producing ch-s. activated vitamin 1,25(oh)2d-calcitriol induces sult2b1b expression and activity. 59 60 thus, completing a circle, where hyperinsulinaemia decreases vitamin d bioavailability, hydroxylation activation and consequently decreasing sult2b1b sulfurylation of sulfate to cholesterol, thereby decreasing the negative charge that aids in dispersion around rbcs, platelets and endothelial cells, thus increasing agglutination and thrombosis. furthermore, sunlight exposure enos sulfate production provides for increased sulfate availability for heparan sulfate proteoglycan (hspg) synthesis; hspgs are robust anticoagulants and buffer glycation damage. 61 ch-s is necessary for rbcs to be able to deform in order to travel through tight vascular spaces while allowing the trafficking of cholesterol between cells to hdl-a1. in addition, sulfate provides a non-haem method of oxygen delivery to oxidative phosphorylation dependent cells. global 'lockdown strategies' may have inadvertently reduced incidental sun exposure and consequently lowered vitamin d and sulfate synthesis. hyperinsulinaemia increases mitochondrial ros, with consequences that are far reaching. healthy robust mitochondria regulate intracellular magnesium (mg 2+ ) pools and modulate mg 2+ concentrations between the cytosol and mitochondrial compartments. 62 hyperinsulinaemia causes increased renal excretion of magnesium, and insulin resistance (ir) reduces intracellular magnesium levels. 63 an mg 2+ deficiency (mgd) may exist in absence of hypomagnesaemia. 64 mgd has been implicated in perturbations of pancreatic beta-cell function, hyperinsulinaemia, ir and cvd due to its diverse and essential roles in an extensive list of cellular metabolic pathways, not least counting atp transport, dna repair capacity and cell viability. mg 2+ is required to transport vitamin d health care delivery, economics and global health care around in the blood, and activation of vitamin d to its active form via hepatic and renal hydroxylation is mg 2+ dependent. 65 clinical manifestations of mgd include, but are not limited to, hyperinsulinaemia's metabolic pathologies such as t2dm, osteoporosis, vitamin d metabolism disorders, cvd and hyperglycaemia. 66 67 there is a strong relationship between mgd and increased oxidative stress. mgd drives decreased expression and activity of antioxidant defence enzymes glutathione peroxidase, sod and catalase and decreased production of glutathione, further taxing mitochondrial health and subsequent increased ros production and consequent oxidative damage to proteins, membranes and haem. 68 69 mgd increases the production of cytokines: il-1β, il-6, tumour necrosis factor α and pai-1. 64 70 hyperinsulinaemia increases production of pai-1, coupled with mgd-induced increased production of pai-1 that inhibits fibrinolysis, together they compound coagulation risk. lower serum magnesium is associated with increased thrombotic risk and slowed fibrinolysis. [71] [72] [73] moreover, in vivo experiments have shown that magnesium has antithrombotic effects and reduces mortality in induced pulmonary thromboembolism. 74 an individual whose system is in a chronic state of hyperinsulinaemia already has increased risk of thrombi/clots. cvd and strokes are typified by thrombi. thus, the association with lower vitamin d may be both a marker and maker of poor health due to hyperinsulinaemia inducing low vitamin d status/availability, as a result of vitamin d sequestration into adipocytes and prevention of hydroxylation by mitochondrial ros sensitive 1α−25ohd-hydroxylase. even with supplementation or adequate sun exposure, a mismatched low vitamin k2 status needed to move ca 2+ into bones would further result in increased plasma ca 2+ inhibition of vit d activation. hyperinsulinaemia mediates thrombi development via multiple modalities, those include but are likely not limited to: (a) inhibition of fibrinolysis, (b) increased mtros production with decreased antioxidant capacity, leading to further oxidation of haem, (c) increasing haem breakdown product carbon monoxide that increases thrombosis and decreases oxygen saturation capacity, (d) increased demand for haem synthesis resulting in increased h 2 o 2 and oxphos independent co 2 production, again further burdening the external respiratory system for removal of co 2 and (e) decreased ch-s production via sulfurylation by sult2b1b sulfotransferase due to hyperinsulinaemia's affect driving low activated vitamin d regulation on sult2b1b, leading to increased rbc and platelet agglutination and thrombosis. when systemic health is already on the edge due to hyperinsulinaemia, then additionally challenged with an extra stressor such as covid-19, it may not be able to handle any more. individuals already in an excess coagulable state, one more straw added in sars-cov-2 may be the straw that breaks the camel's back. given the above theories whereby hyperinsulinaemia aggravates the sars-cov-2 disease progress, lifestyle strategies that have been shown to be effective for managing hyperinsulinaemia and/or type 2 diabetes should also theoretically attenuate sars-cov-2 disease progression. glucose restriction should be a primary focus; this leads to a decreased need/requirement for endogenous and/ or exogenous insulin, thus targeting and managing two problems in one step. 75 76 the importance of managing hyperglycaemia via its, largely dietary, upstream mediator, rather than management of elevated plasma glucose once it has been elevated already, cannot be overemphasised. in an rct conducted by the accord group, 10 251 patients with a mean age of 63 years and median hba1c of 8.1% were randomised to one of two groups, one to target lowering their hba1c to 6%, via receiving intensive therapy (insulin), and the other group to target an hba1c of 7.0%-7.9% following standard therapy. the primary outcomes measured were non-fatal stroke, nonfatal myocardial infarction and cvd death. the intervention group receiving intensive therapy (insulin) to normalise their hba1c had higher mortality, to the extent that after 3.5 years, this intervention was stopped. their hba1c was successfully lowered via the intensive therapy; however, there was no reduction in major cvd events while there was an increase in deaths. 15 implementation in management of hyperglycaemia should be targeted at what causes blood glucose to raise, its upstream effectors, the vast majority of which is from dietary sources. by restricting glucose (consideration to be given with regards to intravenous glucose), this subsequently lowers insulin secretion. 75 methods may include implementing a well-formulated ketogenic diet (wfkd), low carbohydrate healthy fat diet (lchf), low glycaemic load (gl) diet and dietary carbohydrate restriction in as much a practicable way as possible approach. choice in approach may vary for a myriad of reasons; while nutritional ketosis is demonstrated to be safe, it is not necessarily the primary focus in this instance. whereas lowering hyperglycaemia and hyperinsulinaemia are at the forefront of the pathophysiological development of increasing risk factors for poorer outcomes in at risk individuals. implementing a method that helps get patients into a 'fasting mimicking state' using any of these fasting mimicking diets, which has a phenotype of healthy blood glucose (3.5-6.0 mmol/l), insulin (<200 pmol/l) and ketones (<7.0 mmol/l in healthy individuals, ketones at ≤3.0 mmol/l is a respectable concentration in metabolically unhealthy patients), [77] [78] [79] where there is no drive to calorie restrict. again bearing in mind, during acute care settings, the focus is on lowering both glucose and insulin through carbohydrate restriction, whereas the focus is not on achieving any particular ketosis goal, aside from ensuring avoidance of ketoacidosis-ketones ≥7.0 mmol/l 78 and/or presence of ketones plus lowered serum bicarbonate <15-18 mmol/l, with concomitant hyperglycaemia (glucose levels>13.8 mmol/l (250 mg/ dl))-the triad of diabetic ketoacidosis. [80] [81] [82] monitoring serum bicarbonate provides a sensitivity test for any metabolic acidosis with presence of ketones. ketoacidosis does not occur unless there are presence of ketones with hyperglycaemia and bicarbonate levels start trending downwards, indicating insulin insufficiency, as seen in patients with type 1 diabetes mellitus (t1dm) who do not produce enough, if any insulin to regulate ketogenesis with hyperglycaemia. it is important to note, in the case of t2dm, if carbohydrates are ingested, blood glucose will elevate and ketones will lower or be absent due to insulin production in t2dm hyperinsulinaemic individuals, which inhibits ketogenesis. in the case of t1dm, if carbohydrates are ingested and insulin and/or oral hypoglycaemic medications are stopped, these patients may present with both ketosis/ ketoacidosis and hyperglycaemia. although carbohydrate restriction will manage hyperglycaemia (and hyperinsulinaemia in people with t2d), it is never recommended to stop insulin in patients with t1d. however, carbohydrate restriction will likely require the reduction of basal insulin and/or the reduction/cessation of short/rapid acting insulin. focus in clinical management in patients with covid-19 in hospital is to aim to keep them out of progression into the icu. carbohydrate restriction, with a maximum of 90 g of carbohydrate per 24 hours, lchf and wfkd diets implemented in hospital and clinical settings have been shown to be safe and effective. 79 83 in addition, parenteral and enteral glucose-restricted feeding have been shown to be safe and effective should these be required. 76 84 furthermore, coupled with remotely monitored deprescribing of medications, 83 both safety and efficacy have also been demonstrated in the home setting. 79 based on the current clinical data and plausible mechanisms of action that drive an increased risk of infection, the thrombosis risk factor and possible increased thrombi 'load' in at risk individuals, it may be prudent for clinicians to advise stay-at-home at risk and covid-19 positive patients to implement a carbohydrate restricted diet. no clear reference range for insulin exists; current practice has been to use insulin concentrations relative to glucose as a proxy for determining ir, which does not account for hyperinsulinaemia. while patients with an hba1c >40 mmol/l can be presumed to be hyperinsulinaemic by default, a healthy-appearing glucose concentration may be due to perniciously elevated insulin levels (hyperinsulinaemia) regulating blood glucose levels leading to a false negative result. 85 if triglycerides are elevated (>1.7 mmol/l), or the patient has other signs of metabolic syndrome, then there should be a higher suspicion of hyperinsulinaemia. hyperinsulinaemia precedes hyperglycaemia by up to 24 years. 86 insulin regulates lipolysis, fatty acid oxidation and consequently ketogenesis 17 , and while insulin-dependent t1dm requires exogenous insulin to prevent ketoacidosis where plasma ketones exceed >25.0 mmol/l concurrent with hyperglycaemia, 78 a state of hyperinsulinaemia prevents ketogenesis. in healthy people, the presence of ketones below 7.0 mmol/l (absent of hyperglycaemia) have been shown to be safe and even therapeutic. 19 87 however, in metabolically unstable patients, especially when ketosis may need to be induced, reducing the upper reference interval to 3.0 mmol/l may be preferable, while ensuring close monitoring of and no trending downwards of serum bicarbonate. triaging glucose, insulin and ketone body beta-hydroxybutyrate (bhb) concentrations provides a refined ability to ascertain a patient's physiological insulin concentration, where presence of ketones 0.5-3.0 mmol/l, fasting glucose concentration ≤5.6 mmol/l and insulin assay (if practical) results may provide the valuable information needed to determine the degree of carbohydrate restriction a patient requires. presence of bhb even at 0.5 mmol/l with fasting glucose concentration ≤5.6 mmol/l is a proxy marker for insulin levels being inside of a range that is likely to be nonpathological for the patient 77 and indicates physiological insulin homeostasis range. insulin has a 5-15 min pulsatile secretory pattern and an ultradian oscillatory rhythm. 88 a single fasting blood sample may miss its peak; when possible, gold standard practice would be to take three samples, 5 min apart or to consider a 2-hour postprandial level, especially if fasting insulin levels are <180 pmol/l. 85 in order to determine the degree of carbohydrate restriction and deprescribing of medications a patient may require, multiple blood measurements of glucose, insulin and bhb taken at regular time point intervals through the course of multiple days must be performed. this then enables the determination of an individual patient's physiological insulin concentration while also addressing the hyperinsulinaemia and hyperglycaemia in the process. if insulin is unable to be measured, then a normal level of blood glucose (3.5-6.0 mmol/l) in combination with physiologically healthy levels of bhb (0.5-3.0 mmol/l) could be considered a proxy for good insulin control. please note that this may not be accurate if taken within 2 hours of a meal. hba1c, blood glucose, insulin, bhb and bicarbonate should be measured on entrance into hospital or icu. elevated hba1c (>40 mmol/mol, 5.8%) without acidosis (lower bicarbonate <18 mmol/l) [80] [81] [82] is to be treated as hyperinsulinaemia. when necessary, results are to be used to determine the degree of carbohydrate restriction required for either enteral or parenteral management. hourly blood sampling to determine (figure 2): 1. blood glucose (with detailed record of meal and drink intakes). 2. ketone bhb. 3. insulin if feasible (ideally obtain an average from three samples taken over 15 min). 4. depending on the initial and subsequent postprandial levels, this will inform how frequently measurements should be made. health care delivery, economics and global health care 5. blood glucose is expected to respond first to the carbohydrate restriction, depending on the degree of restriction, and the degree and duration of ir and hyperinsulinaemia, the insulin levels may take longer to lower. 6. if control appears to be underway, measurements may be tapered to every 2 hours, then 4 hours or four times per day, depending on the level of control seen. 7. if measured levels do not appear to be responding to the degree of carbohydrate restriction, then it may be necessary to increase the degree of restriction. 8. if glucose levels are going up, and there are concerns about any form of metabolic acidosis (including ketoacidosis), close serum bicarbonate monitoring is advised. close attention must be paid towards the need for deprescribing medications when implementing a very low carbohydrate wfkd. as determined via non-randomised interventional trials and clinical applications of very low carbohydrate diets in patients with type 2 diabetes, fast-acting insulin, sulfonylurea and megalitinide drugs are stopped immediately on induction of very low carbohydrate restriction in order to prevent sudden hypoglycaemic events. if not completely terminating prescribed basal insulin immediately, a reduction of dosage to between 50% and 80% is required. 79 89 hourly glucose readings enable close monitoring to prevent hypoglycaemia in absence of nutritional ketosis and ketoadaptation, where it has been shown considerably lower glucose values may be well tolerated in individuals who are in nutritional ketosis. [90] [91] [92] sodium-glucose cotransporter-2 (sglt2) inhibitors medication should also be discontinued on start of carbohydrate restriction in order to prevent euglycaemic-diabetic-ketoacidosis. 77 additional medications to take into account include: ► gliptins or glitazones -tailored and titrated down on an individualised approach. ► glucagon-like peptide-1 (glp1) receptor agonistsmay be continued. ► metformin -continued if well tolerated, has been shown to improve insulin sensitisation and thus potentially decrease higher insulin requirements, along with enabling the lowering of glucose without a high risk of hypoglycaemia. if a risk of lactic acidosis presents, discontinue. addressing hypertension and antihypertensive medications: refined carbohydrate restriction leads to lowered endogenous and/or exogenous insulin requirements; this results in increased renal sodium secretion and diuresis resulting in hypotension. vigilant and frequent monitoring of blood pressure to avoid hypotension is vital, with according adjustments to antihypertensive medications. increased sodium intake and/or monitoring for hyponatraemia may likely be needed if patients figure 2 clinical management schematic. beta-hydroxybutyrate (bhb), high-density lipoprotein (hdl), low carbohydrate healthy fat diet (lchf), low glycaemic load diet (lg), sodium-glucose cotransporter 2 (sglt2), well-formulated ketogenic diet (wfkd) and upper tolerable limit (utl). experience headaches or light-headedness. 79 it is also important to discontinue sodium restriction recommendations when implementing carbohydrate restriction as low sodium diets have been shown to increase mgd and ir, thus potentiating hyperglycaemia. 93 94 metformin, diuretics and proton pump inhibitors (ppi) drugs have been shown to increase incidence of hypomagnesaemia and are commonly prescribed to patients with t2dm, a condition of hyperinsulinaemia. a reduction in gastric acidity production by ppi drugs decrease mg 2+ solubility, thus decreasing absorption potential in the gastrointestinal (gi) tract; metformin causes gi mg 2+ loss, while diuretics and hyperglycaemia decrease renal tubular reabsorption of mg 2+ . [95] [96] [97] patients implementing very low carbohydrate restriction, where compliance was confirmed by presence of capillary bhb, in a remote setting non-randomised intervention with online medical supervision, were prescribed daily supplementation doses for vitamin d3 and mg 2+ at: 1000-2000 iu vitamin d3, 500 mg magnesium oxide or 200 mg magnesium chloride. 79 other safe and likely beneficial therapies include zinc supplementation (11 mg for men and 8 mg for women, with an upper tolerable limit of 40 mg regardless of sex) 98 and high-noon sensible sun exposure (sans sunscreen), especially given these therapies have been demonstrated to be safe. given the rationale for the clinical management of covid-19, it would be potentially of benefit for clinicians to advise patients and at-risk individuals who are at home to implement these practices, as prevention and earlier management will be more efficacious. 76 79 83 89 while it is not clear what concentration of insulin is ideal for an individual patient, in terms of functional concentrations that work in healthy physiological homeostasis as opposed to chronic elevated concentrations that function in pathological adaptive homeostasis, and drives inflammation and pathological cellular outcomes; healthy glucose concentrations at the cost of hyperinsulinaemia comes at a heavy price. approaches to achieve both healthy glucose regulation and minimal insulin secretion where 'very little does the job' should be managed from a top-down approach, where large changes in blood glucose concentrations are primarily driven by dietary sources, resulting in the subsequent need for more insulin, consequently driving a higher baseline level of insulin. logically restricting dietary carbohydrates results in less extreme oscillations in blood glucose levels and subsequent stimulus and need for insulin. testing dynamic insulin responses to meals and/or controlled glucose loads need to become the normal practice, where the focus is not specifically on ir, which may be physiological glucose sparing in the case for low carbohydrate adherent individuals but to establish if hyperinsulinaemia exists and further enable fine tuning of what degree of carbohydrate restriction is ideal on an individual bases. hyperinsulinaemia drives mtros production and diminishes cellular antioxidative countermeasures; the effects may be subtle yet profound. such as decreasing nadph production leads to a lowered ability to activate inactive 25ohd-calcidiol to its biologically active form, which subsequently affects active 1,25(oh)2dcalcitriol-dependent processes such as sulfurylation activity required to synthesise ch-s in order to prevent agglutination and thrombosis via providing the electronegative repulsion force around rbcs, platelets and endothelial cells. furthermore, antioxidant gsh production is dependent on nadph. hyperinsulinaemia affects vitamin d bioavailability as a result of sequestration into adipocytes. vitamin d synthesis, availability and activation functions in decreasing risk of contracting respiratory infections and decreasing coagulation/thrombosis. hyperinsulinaemia driven increased mtros production taxes haem synthesis, resulting in less haem availability for haem dependent processes, such as maintaining a healthy etc and for haemoglobin to carry oxygen, further driving hypoxia and decreased oxygen saturation capacity. hyperinsulinaemia and hyperglycaemia increases oxidised haem which increases haem catabolism, resulting in chronic increased co production. chronic elevated co levels in turn decrease oxygen saturation capacity and increase risk of dvt leading to increased risk of pe, while long-term lowered oxygen saturation capacity consolidates hypoxia and further mtros. implementing glucose restriction aids to resolve hyperinsulinaemia and hyperglycaemia and their twin effects in poorer outcomes in patients at risk or with covid-19. chronic stimulus of insulin secretion results in hyperinsulinaemia and its downstream pathological sequelae. glucose drives insulin secretion, excessive dietary high gl carbohydrates consumed frequently and chronically drives pathological development of hyperinsulinaemia. clinical management should be focused on lowering carbohydrate consumption to manage both hyperinsulinaemia and hyperglycaemia, coupled with the lowering and describing of glucose management and antihypertensive medications, such as fast-acting and basal insulin. a decrease in dietary carbohydrate and its subsequent effects on lowering insulin secretion leads to rapid changes in blood pressure, requiring vigilant monitoring with describing of antihypertensive drugs, as carbohydrate restriction and resultant decrease in insulin facilitates return of homeostatic regulation of blood pressure. thus, through carbohydrate restriction, three primary factors-hyperinsulinaemia, hyperglycaemia and hypertension-that increase inflammation, coagulation and thrombosis risk are rapidly managed. while on admission, blood glucose and/or insulin may reflect a high normal result, this may not be normal for that person. fasting insulin does not always identify health care delivery, economics and global health care hyperinsulinaemia, a first test for glucose and insulin can appear healthy, as glucose levels sit within the healthy reference range, and insulin not above values seen in non-diabetics. providing a hypothetical example to demonstrate the point, without any clear reference range for fasting insulin, using a hypothetical fasting insulin reference range of 21-153 pmol/l (3.5-25.5 μu/ml), where 1 μu/ml = 6 pmol/l 99 : a patient's first blood test results may show, glucose 5 mmol/l with insulin 144 pmol/l (24 μu/ml), consequently this patient would not be considered hyperinsulinaemic and therefore not triaged to clinical management of carbohydrate restriction in order to decrease risk of coagulation and thrombosis complications of covid-19. in this example, the patient may be maintaining a healthy glucose concentration via a pernicious chronically higher than ideal insulin concentration for that individual. whereas a true non-hyperinsulinaemia individual may also have a fasting blood glucose of 5 mmol/l with insulin 24 pmol/l (4 μu/ml), where the maintenance of a healthy fasting glucose is not sustained by a higher basal insulin level but by maintaining a low carbohydrate consumption that maintains healthy glucose levels and does not frequently stimulate insulin secretion. in both instances, glucose and insulin appear healthy. the only way to know if someone is hyperinsulinaemic (excluding those who have overt hyperglycaemia and/or overtly elevated insulin levels) is by postprandial dynamic testing. in our example above, if both patients were reassessed 2 hours postprandially, the first patient's glucose may have returned to 6.5 mmol/l, while the insulin may be elevated to >1000 pmol/l (166 μu/ml), while the second patient is more likely to have a blood glucose of 5.3 mmol/l and an insulin concentration of 144 pmol/l (24 μu/ml). the limitation of the first readings taken may lead a clinician to think a patient is neither hyperglycaemic nor hyperinsulinaemic, if they only go by the first test and do not perform multiple tests for the first days of admission. postprandial dynamic testing is required to truly ascertain hyperinsulinaemia, therefore clinicians need to extrapolate backwards after the treatment of carbohydrate restriction to subsequently ascertain whether insulin was chronically elevated in that patient and to determine what is a healthy insulin concentration that is specific for individual patients. it must also be emphasised that our proposed management strategy is theoretical based on biochemical principles and practical strategies from dietary control of type 2 diabetes. sars-cov-2 has placed unprecedented strain on many nation's health systems but has also highlighted that metabolic health is key to good immunological health. a well-formulated dietary strategy that restricts carbohydrates should be inexpensive to implement, complementary to current treatment strategies and can be considered as part of home-based treatments. although we may be overcautious with monitoring frequency, additional monitoring is required but may be dependent on the patient's health status; experienced practitioners will be able to refine our recommendations. based on the underlying science, patients with covid-19 admitted with hyperglycaemia and/or hyperinsulinaemia should be theoretically triaged to a restricted carbohydrate management algorithm either enteral or parenteral. the degree of restriction and the level to be determined by serial testing of blood glucose, insulin and ketones. intravenous solutions containing dextrose should be limited where possible. additionally, supplemental vitamin d, magnesium and zinc should be administered. twitter isabella d cooper @i_mitochondria, catherine a p crofts @ pharmacistcath, aseem malhotra @draseemmalhotra, bradley elliott @brads. science, yvoni kyriakidou @yvoni_kyr and kenneth h brookler @kenbrookler acknowledgements many thanks to eleonore de bizemont for language editing and proof reading the manuscript. contributors idc performed the literature search, wrote the original draft and designed the images and reviewed and edited the final manuscript. khb contributed to writing and developing the clinical management and reviewed and edited the final manuscript. cc guided the diagnostic and drug management and reviewed and edited the final manuscript. jjd contributed to writing and editing and reviewed and edited the final manuscript. am, be and yk reviewed and edited the final manuscript. funding the authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors. is ethnicity linked to incidence or outcomes of covid-19? prevalence of and trends in diabetes among adults 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examination of the kraft database nutritional ketosis and mitohormesis: potential implications for mitochondrial function and human health pulsatile insulin secretion, impaired glucose tolerance and type 2 diabetes adapting diabetes medication for low carbohydrate management of type 2 diabetes: a practical guide hormone-fuel interrelationships during fasting alternate fuel utilisation in brain ketoacids? good medicine? low-salt diet increases insulin resistance in healthy subjects dietary salt (sodium chloride) requirement and adverse effects of salt restriction in humans proton pump inhibitorinduced hypomagnesemia: a new challenge the relationship between hypomagnesemia, metformin therapy and cardiovascular disease complicating type 2 diabetes: the fremantle diabetes study proton pump inhibitor-induced hypomagnesemia complicated with serious cardiac arrhythmias dietary reference intakes for vitamin a, vitamin k, arsenic, boron, chromium, copper, iodine, iron, manganese, molybdenum, nickel, silicon, vanadium, and zinc insulin units and conversion factors: a story of truth, boots, and faster half-truths key: cord-017428-euzvhtax authors: janssens, wim; lehouck, an; decramer, marc; gayan-ramirez, ghislaine title: vitamin d and chronic obstructive pulmonary disease date: 2012-02-17 journal: vitamin d and the lung doi: 10.1007/978-1-61779-888-7_11 sha: doc_id: 17428 cord_uid: euzvhtax vitamin d is an important regulator of calcium and bone homeostasis. it is also involved in the regulation of different genes and cellular functions, particularly in the context of inflammation, regeneration and immune control. conversely, vitamin d deficiency which is often found in chronic, infectious and inflammatory diseases is thought to drive or enhance uncontrolled inflammation. chronic obstructive pulmonary disease (copd) is characterized by chronic inflammation of the airways most often because of cigarette smoking. it has been recognized that repetitive airway infections and systemic consequences or co-morbidities also contribute to the progressive nature of copd. vitamin d deficiency is known to sneak in from the early stages of copd, to become highly prevalent at the more severe stages, and may thereby catalyse airway infection, inflammation and systemic consequences. undoubtedly, vitamin d deficiency enhances bone resorption and osteoporosis in copd for which appropriate vitamin d supplementation is recommended. however, conflicting evidence has emerged on the extra-calcemic effects of vitamin d in copd. a recent intervention trial with high-dose supplementation in copd was only able to reduce exacerbation frequency in the subgroup of patients with lowest baseline vitamin d levels. it confirms that severe vitamin d deficiency is a health hazard but that more clinical and experimental studies are needed to explore how vitamin d deficiency may affect airway biology and systemic effects in the context of smoke-induced lung diseases. over the last years, there is an increasing interest in the role of vitamin d and vitamin d de fi ciency in various chronic diseases. besides the well-known effect of vitamin d de fi ciency on bone loss in adults, accumulating evidence also links a low vitamin d nutritional status to highly prevalent chronic illnesses, including cancers, autoimmune diseases, infectious and cardiovascular diseases [1] [2] [3] . vitamin d is now known to have an important in fl uence on immunoregulation and on the expression of antimicrobial peptides. since patients with chronic obstructive pulmonary disease (copd) often integrate all of these co-morbid diseases in one and given that most of copd exacerbations are triggered by bacterial and viral infection, vitamin d could play a key role in the pathogenesis of this disease. this chapter aims to discuss the prevalence and determinants of vitamin d de fi ciency in copd, the wellknown effect of vitamin d in the development and treatment of copd-associated osteoporosis and its potential role in the uncontrolled in fl ammatory cascade and systemic consequences of the disease. copd is a chronic disease characterized by air fl ow limitation that is progressive, not fully reversible and associated with an abnormal in fl ammatory response of the lungs to noxious particles or gases. in western countries, tobacco smoke is the major cause for copd, accounting for 90-95% of the cases. since only 20% of smokers develop severe copd, other factors (biological, hereditary, environmental) must be involved [ 4 ] . narrowing of the airways by in fl ammation, mucus production, irreversible remodelling and emphysema results in a limitation of expiratory air fl ow and disturbed gas exchange [ 5 ] . currently, it is estimated that 210 million people suffer from copd worldwide, a number that is still increasing. by 2020, the world health organization predicts that copd will rise from the sixth to the third leading cause of death, next to only cardiovascular disease and cancer [ 6 ] . according to the global obstructive lung disease (gold) de fi nition, diagnosis of copd should be based on spirometry measurements with a post-bronchodilator forced expiratory volume in 1 s over forced vital capacity ratio (fev 1 /fvc) below 0.7. subsequently, copd can be categorized in different stages of severity (gold stages) going from mild, moderate and severe to very severe disease according to fev 1 [ 7 ] . it should be noted, however, that the majority of copd patients, especially in the early stages of the disease, report no complaints, do not perform spirometry and thus are unaware of their disease. treatment for copd focuses on minimizing symptoms and preventing exacerbations. with the exception of smoking cessation, so far, no treatment has clearly proven to signi fi cantly modify copd disease progression. recent data, however, indicate that pharmacological intervention with inhalation therapy may slow down the yearly decline of fev 1 [8] [9] [10] . the pathophysiology of copd is characterized by an increased in fl ammatory response in the airways and parenchyma. besides an increase in number of neutrophils, macrophages and t-lymphocytes, copd is associated with elevated concentrations of various cytokines, including interleukins (il-1, il-6 and il-8), tumour necrosis factor alpha (tnf-a ), oxidative stress and the release of proteolytic enzymes. cigarette smoke is known to cause a direct injury of the airway epithelial cells leading to the release of endogenous intracellular molecules or danger-associated molecular patterns (damps). these signals are recognized by toll-like receptors on epithelial cells which initiate a non-speci fi c in fl ammatory response. as reaction on the release of early cytokines (tnf-a , il-1, il-8), macrophages, neutrophils and dendritic cells are recruited to the site of in fl ammation [ 11 ] . proteolytic enzymes and reactive oxygen species are released which may cause further damage to the lung. next, self-antigens and antigens coming from pathogens bound to dendritic cells can activate naive t cells into th1 cells [ 12 ] and may lead to antibody producing b cells. this adaptive immune response may then further enhance the in fl ammatory cascade. in addition, the observed reduction of regulatory t cells (treg) in copd lungs against the rise of pro-in fl ammatory th17 cells is pointing towards an impaired immune regulation in copd [ 13 ] . macrophages are believed to play a central role in the pathophysiology of copd [ 14 ] . they are important sources of pro-in fl ammatory mediators but may also protect against infection by phagocytosis. in copd, alveolar macrophages appear to be resistant to the anti-in fl ammatory effects of corticosteroids by the reduced activity of histone deacetylase 2 (hdac2), a nuclear enzyme that switches off in fl ammatory genes activated by the nuclear factor nf-k b [ 15 ] . additionally, taylor and colleagues recently demonstrated that the phagocytotic capacity of macrophages of copd patients is impaired, which may lead to bacterial colonization and increased exacerbation frequency [ 16 ] . overall, the complexity of the pathogenesis of copd with different mechanisms and risk factors is re fl ected in the broad variation of clinical phenotypes. with progression of the disease, as marked by a decline of forced expiratory volume in 1 s (fev 1 ), copd patients become more prone to exacerbations. an exacerbation of copd is an acute worsening of respiratory symptoms which is associated with increased symptoms and worsening of lung function. recent studies have shown that quality of life and health status of patients are mainly determined by the presence and frequency of such exacerbations which, in turn, may lead to a faster decline in fev 1 [ 17 ] . although viral and bacterial infections are assumed to be the major cause of exacerbations, other factors including environmental pollution and allergens have also been identi fi ed [ 18 ] . the exact role of bacterial infection in copd exacerbations is often biased by bacterial colonization of the airways during stable state with the same organisms as those isolated at exacerbations: haemophilus in fl uenzae , streptococcus pneumoniae , moraxella catarrhalis , staphylococcus aureus and pseudomonas aeruginosa . different studies have shown that prevalence and load of organisms increases during an exacerbation [ 19 ] , but recent evidence indicates that the acquisition of a new bacterial strain is likely the main trigger of an exacerbation [ 20, 21 ] . besides bacterial infections, exacerbations may also be triggered by viral infections, including infections with rhinoviruses , coronavirus , respiratory syncytial virus , in fl uenza , parain fl uenza and adenoviru s. moreover, recently, a frequent exacerbator phenotype has been identi fi ed suggesting that the innate and adaptive immune defence of the host also contributes to exacerbation susceptibility and that individualized therapy may become important in the nearby future [ 22 ] . copd is not restricted to the lungs but also associated with systemic in fl ammation and increased co-morbidities which are now considered as important targets in the therapeutic approach of copd. increased systemic levels of tnf-a , il-6 and c-reactive protein (crp) are commonly found in patients with copd [ 23 ] . common co-morbidities of copd include lung cancer, cardiovascular disease, osteoporosis, diabetes and skeletal muscle dysfunction [ 24, 25 ] . whether these co-morbidities are caused by the underlying disease or just co-exist because of common risk factors such as smoking, ageing and inactivity is far from understood. most likely, both mechanisms play together and the attractive hypothesis of in fl ammation in the lung "spilling over" into the systemic circulation and affecting other organs is corroborating this idea [ 26 ] . whatever the mechanism may be, the presence of these co-morbidities clearly contributes to the poor outcome in copd [ 27, 28 ] . vitamin d is generally obtained by photosynthesis in the skin but can also be derived from nutrition (fatty fi sh, fi sh liver oils and dairy products). ultraviolet light catalyses the fi rst step in the vitamin d biosynthesis, which is the conversion of 7-dehydrocholesterol into pre-vitamin d. the next step is a hydroxylation in the liver into 25-ohd, which then circulates in serum with a long half-life of 15 days. next, 25-ohd is hydroxylated again into the active vitamin d metabolite 1,25(oh) 2 d by 1 ahydroxylase (cyp27b1) in the kidney which is controlled by serum levels of calcium and phosphate and regulating hormones such as parathyroid hormone (pth), calcitonin and phosphatonins. 1,25(oh) 2 d also induces the expression of a 24-hydroxylase (cyp24a1) which catabolizes 25-ohd and 1,25(oh) 2 d into biologically inactive, water-soluble metabolites, thereby serving as its own negative feedback. the majority of 25-ohd and 1,25(oh) 2 d are bound to plasma proteins, of which more than 90% to the vitamin d binding protein (dbp), which carry out the delivery to their respective target organs [ 29 ] . 1,25(oh) 2 d may thus bind to the nuclear vitamin d receptor (vdr) in the intestine, bone, kidney and parathyroid gland cells, resulting in the maintenance of normal serum calcium and phosphorus levels and their related effects on mineralization and turnover of bone [ 30, 31 ] . since 1 a -hydroxylase and the nuclear receptor vdr are widely present in cells of several extrarenal tissues such as skin, bone, prostate and immune cells, local 1,25(oh) 2 d concentrations can also exert different autocrine and paracrine functions. although the enzyme found here is identical to the one that is expressed in the kidney, its expression is regulated by immune signals instead of mediators of bone and calcium homeostasis [ 32, 33 ] . 1,25(oh) 2 d mediates its effects by binding to the nuclear vdr the vitamin-vdr complex may then activate vitamin d response elements (vdre) on genes involved in different cellular processes. it is estimated that about 3% of the mouse/human genome is regulated by vitamin d [ 34 ] . directly or indirectly, vitamin d controls many genes that are involved in the regulation of cellular proliferation, differentiation and apoptosis of healthy and pathological cells. because of its long half-life, 25-ohd is typically used to determine vitamin d status. it re fl ects vitamin d synthesized in the skin as well as that acquired from the diet and vitamin d degradation by catabolizing enzymes. when focusing on the calcemic effects, vitamin d insuf fi ciency is best de fi ned as a 25-ohd level below 20 ng/ml (50 nmol/l) [ 2, 35 ] . a sensitive parameter to determine vitamin d de fi ciency is serum levels of pth. older data have clearly demonstrated that levels of 25-ohd below 20 ng/ml are associated with an increase in pth expression [ 36 ] . based on observational studies, several experts have suggested that, for non-calcemic effects, serum levels of at least 30 ng/ml (75 nmol/l) are required, but so far, intervention studies to support this are lacking. dietary sources of vitamin d are limited, and food forti fi cation is mostly inadequate or nonexistent. although sunlight is the most important source of vitamin d, several other factors can in fl uence the amount of vitamin d that can be synthesized: season, latitude, clothing, the use of sunscreen, darker skin pigmentation and age. for example, ageing is associated with decreased concentrations of 7-dehydrocholesterol in the skin, thereby reducing the capacity to synthesize vitamin d. even if regularly exposed to sunlight, elderly people produce 75% less cutaneous vitamin d than compared to young adults [ 36 ] . due to cultural habits and clothing, even those who live in sunny climates are commonly found to be de fi cient in vitamin d. data from the third national health and nutrition examination survey (nhanes iii) revealed that in us adults, only 30% of the white population and 5% of the african americans had levels of vitamin d of at least 30 ng/ml [ 37 ] . according to the current de fi nitions, it is estimated that more than one billion people worldwide have impaired serum levels of vitamin d. as current supplementation regimens with a daily dose of 800-1,000 iu of vitamin d restore de fi cient serum 25-ohd levels in a general adult population to concentrations above 20 ng/ml, higher doses are probably required to increase 25-ohd levels to even higher levels that may be needed for non-calcemic diseases in a population at risk [ 38, 39 ] . at present, we can only speculate on what such ideal target range of 25-ohd levels is to maximally exploit these extra-calcemic effects [ 40 ] . we should also acknowledge that an extensive expert analysis of the potential effects of vitamin d supplementation on the health outcome of north-american subjects concluded that there is presently insuf fi cient evidence for extraskeletal bene fi ts of vitamin d therapy and that only new randomized controlled trials will be able to de fi ne such effect [ 41 ] . copd patients should be considered at high risk to become vitamin d de fi cient for a variety of reasons: lower food intake, reduced capacity for vitamin d synthesis of the skin by ageing and smoking, the absence of outdoor activity and sun exposure, impaired activation by renal dysfunction and a lower storage capacity in muscles or fat by wasting may all contribute to a defective vitamin d status in copd [ 2 ] . in 2005, black and colleagues who examined spirometric data from the third national health and nutrition examination survey, a cross-sectional survey on 14,091 us civilians over 20 years of age, discovered an important link between vitamin d and spirometric data [ 42 ] . after adjustment for potential confounders, a strong relationship between serum levels of 25-ohd and pulmonary function, as assessed by fev 1 and fvc, was found. although a signi fi cant correlation with airway obstruction could not be found, the observed dose-response relationship suggested a causal link [ 43 ] . the observation that smoking african-americans more rapidly develop severe air fl ow obstruction as compared to caucasians is also in agreement with the idea that a presumed lower vitamin d status in african-americans correlates with an increased susceptibility to copd [ 44 ] . furthermore, different genetic variants involved in the vitamin d signalling pathway are shown to determine 25-ohd levels [ 45 ] , and some of these variants have repeatedly been associated with copd. for instance, variants of the dbp gene ( gc ) have been shown to be protective or risk factors for copd [ 46 ] , and a more recent robust candidate gene study in two large data sets identi fi ed the gc genes as susceptibility loci for copd [ 47 ] . in a study of forli and colleagues, vitamin d de fi ciency (<20 ng/ml) was found in more than 50% of a cohort waiting for lung transplantation [ 48 ] , but they failed to compare vitamin d serum levels with a matched control group. however, we recently demonstrated in a group of 414 smoking individuals that patients with copd were more likely to suffer from vitamin d de fi ciency than aged and gender-matched healthy control smokers without copd [ 49 ] . in copd patients, we found a signi fi cant association between vitamin d serum levels and severity of disease assessed by fev 1 . the prevalence of vitamin d de fi ciency de fi ned by 25-ohd levels below 20 ng/ml increased to, respectively, 60% and 75% in severe (gold 3) and very severe copd patients (gold 4) (fig. 11.1 ) . interestingly, we also showed that 25-ohd levels were determined by genetic variants in the vitamin d binding gene ( gc) after correcting for age, gender, smoking history and disease severity and that homozygous carriers of the rs7041 t allele with lowest vitamin d levels exhibited an increased risk for copd. although the risk effect of certain gc alleles may relate to a lower bioavailability of vitamin d, other authors have suggested that protein variants of dbp may directly affect in fl ammation in the airways [ 50 ] . wood and colleagues, for instance, demonstrated that local dbp expression in sputum of copd patients correlates with macrophage phagocytosis capacity [ 49 ] suggesting that the risk effect of dbp may be found in a different activation of macrophages [ 51 ] . a recent population based study in 2,943 individuals living in hertfordshire (uk) found reduced vitamin d intake in the copd subgroup of 521 individuals compared to the non-copd subjects but was not able to con fi rm the positive association between 25-ohd serum levels and fev 1 or fvc [ 52 ] . surprisingly, shaheen et al. found that patients with highest vitamin d levels were more likely to have copd. they concluded that in contrast to a prudent dietary pattern with the intake of high amounts of antioxidants [ 53 ] , vitamin d was not an important determinant for adult pulmonary function and risk of copd. unfortunately, more than 50% of their population was taking dietary vitamin d supplements for unspeci fi ed reasons, which may have affected their analysis and biased their conclusions. finally, in a small sub-study of the lung health study iii conducted in 198 selected individuals, mean 25-ohd levels of copd patients with a rapid fev 1 decline were found to be similar to mean 25-ohd levels of patients with a slow decline, suggesting again that vitamin d de fi ciency does not contribute to copd progression [ 54 ] . together, from these con fl icting data, it is clear that more prospective studies are needed to determine causal relationships between vitamin d de fi ciency and pulmonary function in copd. but even if causality cannot be found for pulmonary function variables, vitamin d de fi ciency may still alter the disease course by affecting other outcomes such as respiratory tract infections or co-morbidities. low levels of vitamin d result in low bioavailability of calcium which stimulates parathyroid glands to increase secretion of pth. in the kidneys, pth reduces the reabsorption of phosphate from the proximal tubule and increases calcium reabsorption in the distal tubule, resulting in a net increase in calcium/phosphate ratio. pth also induces renal 1 a -hydroxylase expression which then leads to an increased production of active 1,25(oh) 2 d. 1,25(oh) 2 d enhances intestinal calcium absorption and acts on the immature osteoblastic cells to stimulate osteoclastogenesis through the rankl/rank regulatory system, with enhanced bone resorption and mobilization of calcium from the bone compartment, causing osteopenia, osteoporosis and increased risk for bone fractures [ 55 ] . this results in higher levels of calcium and 1,25(oh) 2 d with a negative feedback on pth and a subsequent limitation of bone resorption. osteoporosis is a skeletal disorder which is characterized by compromised bone strength resulting in a higher susceptibility to fractures. bone strength is determined by the structural quality of the bone and by bone mineral density, the latter measured by dual x-ray absorptiometry (dxa) and used to de fi ne osteoporosis. osteoporosis is a major health problem as osteoporotic fractures are a frequent cause of signi fi cant and long-lasting morbidity in older individuals. hip fractures and other types of nonvertebral fractures account for most of the burden of osteoporosis, with increased mortality, functional decline, loss of quality of life and need for institutionalization [ 56 ] . female gender, advancing age, a history of fragility fractures, current or former smoking, low body weight or weight loss and the use of systemic glucocorticoids are well-established risk factors for osteoporosis and osteoporotic fractures. as many of these risk factors are present in copd patients, especially at the more severe stages, it should be no surprise that osteoporosis and copd are strongly linked. a recent review of graat-verboom et al. con fi rmed low body mass, disease severity, use of corticosteroids, age and female gender to be independent risk factors for osteoporosis in copd [ 57 ] . the majority of studies have reported an increased risk for osteoporosis with decreasing fev 1 (fig. 11 .2 ) [59] [60] [61] . the prevalence of osteoporosis in copd varies between 9% and 59% depending on the diagnostic methods used, the population studied and the severity of the underlying respiratory disease [ 57 ] . sin and colleagues used the nhanes iii data to demonstrate that air fl ow obstruction is independently associated with reduced bone mineral density [ 59 ] . in their population-based cohort of 9,502 non-hispanic white participants, 33% of all women with severe copd had osteoporosis whereas almost all women with mild airway obstruction had osteopenia. in comparison, men were at lower risk than women but still, in men with severe copd, the prevalence of osteoporosis and osteopenia was 11% and 60%, respectively, which was approximately three times higher than expected. most studies looking at prevalence of osteoporosis have used dexa scans which measure bone mineral density but do not evaluate micro-architectural changes of the bone. it is known that these microarchitectural changes may equally cause fragility fractures, even with normal bone density, and should therefore be considered to be osteoporotic as well. when taking dexa measures and vertebral fragility fractures into account, graat-verboom et al. found that prevalence of osteoporosis almost doubled in 250 copd outpatients [ 62 ] . it indicates that prevalence of osteoporosis in copd might be much higher than the current prevalence data suggest [ 63 ] . interesting relationships are also found with emphysema which is associated with reduced bone mineral density and lower body mass index and which may represent a clinical phenotype at risk for osteoporosis [ 64, 65 ] . visual emphysema as assessed by ct scan was found to be an independent risk factor for osteopenia/osteoporosis [ 66 ] , and different bone turnover markers are increased in copd. recent data also show that osteoprotegerin, which is critically involved in bone turnover by blocking rank-rankl interaction, may become a useful marker for parenchymal lung destruction in copd [ 67, 68 ] . it is currently not known whether the vitamin d pathway is involved in the speci fi c development of emphysema, but studies in laboratory animals certainly corroborate this idea [ 69, 70 ] . the consequences of osteoporotic fragility fractures in a copd population may be detrimental. in hip-fracture patients, mortality is close to 20% within 1 year, and of those who do survive the fracture, again, some 20% will have to be institutionalized because of its functional consequences [ 71 ] . the exact prevalence of hip fractures in copd patients has not been studied in detail, but it is probable that the impact of such events in disabled copd patients will be even worse. additionally, vertebral compression fractures can lead to back pain, functional impairments, increased kyphosis with reduced rib cage mobility and decline of pulmonary function [72] [73] [74] . the impact of loss of vertebral height on pulmonary deterioration in copd has been demonstrated by leech and colleagues who found that vital capacity and total lung capacity incrementally declined as the number of thoracic vertebral fractures increased [ 72 ] . in the eolo study, a large copd cohort of up to 3,000 participants, more than 40%, had one or more vertebral fractures and the prevalence signi fi cantly correlated with severity of disease [ 75 ] . kyphosis related to osteoporosis may also cause limitation in rib mobility and inspiratory muscle dysfunction and was also correlated with loss of fev 1 and fvc [ 76 ] . there is no doubt that vitamin d protects against osteoporosis and osteoporotic fractures, and therefore, suf fi cient vitamin d supplementation should be encouraged. the fact that the majority of copd patients are of older age, have many common risk factors for osteoporosis and are more likely to be de fi cient in vitamin d supports standard supplementation, especially at the more severe stages of disease. a daily dose of 700-800 iu of vitamin d together with an adequate daily calcium intake (1,000 mg) is probably the best strategy to prevent fractures in older subjects. such supplementation is known to restore low serum 25-ohd levels in a general adult population to concentrations above the 20 ng/ml (50 nmol/l) threshold. patients with copd, particularly those on systemic corticosteroids, should also be considered for a dexa scan and if needed, osteoporosis medication [ 58 ] . even though causality and therapeutic bene fi ts of vitamin d remain to be established for pulmonary in fl ammation and other co-morbidities, prevention of vertebral fractures will positively affect pulmonary function [ 75 ] . along with a progressive loss of pulmonary function, copd patients become more prone to acute copd exacerbations which are an important cause of hospitalization, impaired quality of life and mortality [ 77 ] . appropriate antimicrobial treatment is essential in the treatment of acute bacterial exacerbations whereas in case of colonization, repetitive and long-term antibiotic treatments are still avoided as they contribute to the multi-resistance of colonizing strains. anti-in fl ammatory treatments different from inhaled and systemic corticosteroids are currently validated in copd to reduce exacerbations on top of bronchodilator therapy. pde4 inhibitors and neo-macrolides are the most promising agents from this perspective and seem to be bene fi cial for a subgroup of patients with repetitive exacerbations [78] [79] [80] . an attractive alternative approach might be the up-regulation of the innate immune defence system with vitamin d, particularly with regard to antimicrobial polypeptides [ 81 ] . wang and colleagues demonstrated that in different cell types such as epithelial cells and white blood cells, the genes encoding for antimicrobial polypeptides such as cathelicidin (ll-37) and b -defensin are driven by vdr elements containing promoters [ 82 ] . in human monocytes, tlr activation up-regulates expression of the vdr and the 1-a -hydroxylase genes, leading to induction of ll-37 and killing of intracellular mycobacterium tuberculosis [ 83 ] . ll-37 is also found to be very effective in the killing of a number of antibiotic-resistant strains such as pseudomonas and s. aureus , different viruses and chlamydia [ 84, 85 ] . as ll-37 is diffusely expressed in the surface epithelia of human airways, in the submucosal glands and in macrophages and neutrophils [ 86 ] , substitution of local vitamin d insuf fi ciency may reduce bacterial load and concomitant airway in fl ammation [ 87 ] . apart from its potential bene fi t on bacterial eradication, vitamin d may also down-regulate the complex in fl ammatory cascade at several levels. in vitro vitamin d can reduce the expression of tlrs which are critical in the induction of the early immune response [ 88 ] . high levels of vitamin d also inhibit dendritic cell maturation with lower expression of mhc class ii molecules, down-regulation of co-stimulatory molecules and lower production of pro-in fl ammatory cytokines such as il-2, il-12, ifn-g and il-23 [ 33, 89 ] . in several mouse models, vitamin d also leads to a switch from a th1/th17 responses towards a th2 and regulatory t cell answer [ 1, [90] [91] [92] . low serum levels of vitamin d have also been correlated with a decreased phagocytic activity of macrophages in patients with rickets [ 93 ] whereas antimicrobial activity of macrophages against m. tuberculosis could be increased by vitamin d supplementation [ 94 ] . overall, the potential of vitamin d in reducing proin fl ammatory processes of the innate and adaptive immune system, together with an increased bacterial eradication by self antimicrobial peptides and enhanced macrophage phagocytosis, may offer great potential in the treatment of exacerbations. indirect clinical evidence for such hypothesis may be found in the observation that exacerbations of copd are most common in winter, when 25-ohd levels are lowest. in addition, data from nhanes iii showed that upper respiratory tract infections were most frequent in patients with lowest vitamin d levels. to further investigate such intriguing hypothesis, a randomized placebo-controlled intervention trial was performed to evaluate the effect of vitamin d supplementation in copd patients, prone to exacerbations [ 95 ] . one hundred and eighty-two patients with moderate to very severe copd and a history of recent exacerbations were supplemented with 100,000 iu vitamin d or placebo every 4 weeks over one year. because of high-dose supplementation mean, 25-ohd serum levels increased signi fi cantly in the intervention arm and reached stable mean serum levels of 50 ng/ml, which is in the therapeutic range of the hypothesized extra-calcemic effects [ 2 ] . however, despite effective supplementation, no signi fi cant difference in time to fi rst exacerbation, time to fi rst hospitalization and exacerbation rate could be observed between the intervention and the control group. the absence of a therapeutic effect of vitamin d may relate to the fact that most of the patients presented with severe disease and were on maximal inhalation therapy. as all these treatments are known to reduce exacerbations [ 96, 97 ] , it is likely that any additional effect of vitamin d on top of regular treatment is more dif fi cult to obtain. intervention within the more early copd stages taking less medications might therefore be more effective which is in line with the idea that such milder stages are also more sensitive to disease modi fi cation [ 98 ] . interestingly, a signi fi cant baseline vitamin level by treatment interaction was observed for exacerbation rates. when performing a post hoc analysis in the subgroup of patients with very de fi cient vitamin d levels at baseline (<10 ng/ml), a signi fi cant 43% reduction of the number of exacerbations was observed in the intervention group. as one out of six copd patients in the trial presented with such asymptomatic low baseline 25-ohd levels which persisted during the entire course of the study, further focus and future studies on this important subgroup may be warranted, eventually resulting in better patient-tailored interventions. recently, a frequent exacerbator phenotype has been indenti fi ed suggesting that individualized therapy-including appropriate vitamin d substitution-may become important [ 22 ] . we also assessed for the presence and load of pathogenic bacteria in cultures of morning sputa during the trial but found no difference in eradication between both study arms. however, monocyte phagocytosis capacity in peripheral blood monocytes of patients receiving vitamin d was signi fi cantly increased compared to the placebo group, an effect which was more pronounced in the subgroup with lowest baseline levels. it is therefore tempting to speculate that the signi fi cant reduction of exacerbations in the vitamin d de fi cient subgroup is explained by an important upregulation of impaired phagocytosis capacity [ 51 ] . so far, hard evidence for this mechanism is lacking. finally, it should be noted that the lack of an overall effect could also relate to local vitamin d insensitivity because of epigenetic modi fi cations. in line with the known corticosteroid resistance in copd [ 99 ] , recent studies in cancer have shown that epigenetic silencing of key enzymes of the vitamin d pathway may occur leaving tumour cells insensitive to vitamin d therapy [ 100, 101 ] . at least, epigenetic modi fi cations especially in the context of smoking or poor diet may explain why many observations suggest causal relationships between vitamin d de fi ciency and in fl ammatory diseases whilst supplementation later on in the disease cannot reverse this process [ 102 ] . skeletal muscle weakness is common in moderate to severe copd and is an independent predictor of respiratory failure and death [ 103 ] . although the underlying mechanisms of skeletal muscle dysfunction in copd are not entirely understood, it is generally accepted that the combination of disuse because of respiratory limitation, with elevated oxidative stress, systemic in fl ammation, hypoxia and frequent steroid intake, is the main cause of deterioration [ 25 ] . rehabilitation programmes in copd are proven successful, but there is still a large variability in training effectivity [ 104, 105 ] . since muscle weakness is a prominent feature in rickets and chronic renal failure, and epidemiological studies found a positive association between 25-ohd levels and lower extremity function in older persons, vitamin d could be an important factor in muscle health [ 106 ] . in elderly individuals, vitamin d status predicts physical performance and consequent decline during long-term follow-up [ 107 ] . several double-blind randomized controlled trials demonstrated that vitamin d supplementation increased muscle strength and balance and reduced the risk of falling in elderly [ 108 ] . although a recent meta-analysis looking at the effect of vitamin d supplementation on muscle strength was negative, positive effects were still found in very de fi cient patients [ 109 ] . moreover, the cross-sectional analysis from nhanes indicated that muscle strength continued to increase throughout 25-ohd serum levels of 9-37 ng/ml, indicating that for obtaining bene fi cial effects on the muscle, higher dose supplementation might be necessary [ 106 ] . on the pathological level, adults with vitamin d de fi ciency show predominantly type ii muscle fi bre atrophy [ 110 ] with several muscle abnormalities such as enlarged inter fi brillar spaces, in fi ltration of fat, fi brosis and glycogen granules [ 111 ] . conversely, increase in relative fi bre composition and type ii fi bre dimensions has been reported in elderly after treatment with vitamin d [ 112 ] . these type ii fi bres are also the fi rst to be recruited to prevent falling [ 113 ] , which may explain why vitamin d supplementation is shown to reduce falling [ 114 ] . in copd, limb muscle adaptation leads to a decrease of the proportion of slow oxidative type i fi bres with a relative increase towards glycolytic type ii fi bres [ 115, 116 ] , those fi bres that are preferentially affected by vitamin d de fi ciency. therefore, vitamin d de fi ciency may be of particular concern in copd patients with muscle weakness and dysfunction. the exact mechanisms by which vitamin d affect muscle function are not fully understood. however, 1,25(oh) 2 d may impair muscle function by altering calcium regulation. in particular, 1,25(oh) 2 d is responsible for the active calcium transportation into the sarcoplasmic reticulum by ca-atpase. it is known to regulate ca-atpase by phosphorylation of proteins in the sarcoplasmic reticulum membrane; it can increase phosphate transport across the membrane and interacts with calmodulin [ 110, 117 ] . interestingly, calmodulin is highly sensitive to oxidative stress [ 118 ] , a typical feature of copd, and 1,25(oh) 2 d may yield antioxidant properties. thus, both vitamin d de fi ciency and increased oxidative stress through, e.g. smoking may act synergistically impairing calmodulin function, muscle structure and contractility. 1,25(oh) 2 d has also an important role in protein synthesis in the muscle cell, mediated through nuclear receptor-mediated gene transcription [ 113 ] . for example, it can affect actin and troponin c content, two major contractile proteins in skeletal muscle [ 119 ] , or may up-regulate gene expression of muscular growth factors, for instance, igf-i [ 120 ] . although it is tempting to extrapolate these vitamin d-mediated actions in skeletal muscles of healthy or elderly subjects [ 108, 121 ] to a speci fi c population of copd patients, it is still to be shown that vitamin d de fi ciency contributes to the observed muscle weakness in copd. at present, there is no direct evidence for such causal relationship but the observation that vdr genotypes may in fl uence quadriceps strength in copd patients is in line with this assumption [ 122 ] . recent data also show that vitamin d de fi cient copd patients referred for rehabilitation have a higher risk for dropout and reduced bene fi t on walking endurance [ 123 ] . in a post hoc analysis in moderate to severe copd, we also found a signi fi cant effect of high-dose vitamin d supplementation on top of 3 months of rehabilitation in terms of improved exercise capacity [ 124 ] . therefore, randomized controlled trials investigating if supplementation of vitamin d de fi ciency may positively affect muscle force, muscle function and general copd outcomes are urgently needed. in the last years, many clinical studies have associated low vitamin d levels to prevalence and incidence of cancer, including lung cancer [ 125, 126 ] . several studies associate vitamin d de fi ciency with autoimmune diseases like type i diabetes, multiple sclerosis and rheumatoid arthritis [127] [128] [129] . de fi cient vitamin d levels have been linked to chronic infections such as tuberculosis and acute viral infections like in fl uenza or upper tract respiratory infections [130] [131] [132] [133] . similar data are also available which link vitamin d de fi ciency to cardiovascular diseases, arterial hypertension and even all cause mortality [ 134 ] . it is beyond the scope of this book chapter to review all evidence on vitamin d in these different chronic diseases, but it is striking that many of them are currently considered to be co-morbid conditions of copd and accepted as important determinants of copd outcome and prognosis [ 23, 25 ] . tackling vitamin d-mediated effects in these co-morbid conditions may therefore indirectly improve copd status [ 135 ] . it should be stressed, however, that the above mentioned relationships between vitamin d de fi ciency and different chronic diseases are speculative and most often rely on cross-sectional and retrospective observations or on evidence of in vitro and animal research. in humans, placebo-controlled intervention studies and observational studies with prospective long-term follow-up speci fi cally designed to demonstrate causal relationships are often lacking. moreover, recent intervention studies with vitamin d supplementation in multiple sclerosis, diabetes, in fl uenza and tuberculosis have reported disappointing results, most often by their limitation of statistical power or insuf fi cient supplementation [136] [137] [138] [139] . recent expert analysis therefore concluded that there is yet insuf fi cient evidence for extra-calcemic bene fi ts of vitamin d therapy and that more randomized placebo-controlled interventions trials are needed to de fi ne such effects [ 41 ] . for copd in particular, intervention studies targeting co-morbid conditions to improve copd-speci fi c outcomes will be needed and in analogy with the ongoing trial on statins in copd patients ( www.clinicaltrials.gov ), one may think about a large intervention study with vitamin d supplements. indirectly or directly, vitamin d is also believed to regulate extracellular matrix homeostasis in other tissues than bone, within particular lung and skin tissue via the control of transforming growth factor-b , matrix metalloproteinase and plasminogen activator systems [140] [141] [142] [143] . there is compelling evidence that vitamin d plays a key role in foetal lung growth, development and maturation [ 144, 145 ] . although 1.25 (oh) 2 d toxicity in klotho-null mice results in a phenotype of skin atrophy, osteoporosis and emphysema [ 146 ] , recent data in mice show that severe vitamin d de fi ciency from early life also results in a impaired lung function by differences in lung volume and growth [ 69 ] . evidence from human epidemiological studies also suggests that higher prenatal uptake of vitamin d protects against childhood wheezing [ 147 ] . as impaired lung growth and childhood asthma are known risk factors for copd at later age [ 148, 149 ] , the causal link between vitamin d de fi ciency and copd may therefore already exist from early childhood on. again, recent evidence from animal studies corroborates this idea. vdr knockout mice develop emphysematous airspace enlargement which is associated with the up-regulation of matrix metalloproteinases in the lung, an increased in fl ux of in fl ammatory cells and the development of typical lymphoid aggregates around the peripheral airways [ 70 ] . the evidence that the vitamin d pathway plays a pivotal role in the biology of healthy and diseased lungs is compelling. as with many chronic diseases, vitamin d de fi ciency is highly prevalent in copd and occurs more frequently with increasing disease severity. such de fi ciency may not only enhance local airway in fl ammation but may also induce or accelerate ongoing co-morbid diseases and subsequently impair the general prognosis of the disease (fig. 11.3 ). so far, there is only hard evidence for a causal role of vitamin d de fi ciency in the pathogenesis of copdrelated osteoporosis. for extra-calcemic effects, a recent randomized controlled trial demonstrated no overall effect of high-dose supplementation on exacerbations but was supportive for an important effect in a limited subgroup of patients highly de fi cient for vitamin d. before embarking on new intervention trials with vitamin d in copd targeting subgroups, more fundamental research is needed to learn how vitamin d and its de fi ciency interact with smoking in the development of copd. only then we will be able to understand why so far most intervention trials with vitamin d have failed to yield important health bene fi ts in chronic diseases including copd. vitamin d and health: perspectives from mice and man vitamin d de fi ciency vitamin d and human health: lessons from vitamin d receptor null mice gene-environment interactions in chronic obstructive pulmonary disease chronic obstructive pulmonary disease projections of global mortality and burden of disease from 2002 to 2030 global strategy for the diagnosis, management, and prevention of chronic obstructive pulmonary disease: gold executive summary effect of pharmacotherapy on rate of decline of lung function in chronic obstructive pulmonary disease: results from the torch study effect of tiotropium on outcomes in patients with moderate chronic obstructive pulmonary disease (uplift): a prespeci fi ed subgroup analysis of a randomised controlled trial tiotropium as a fi rst maintenance drug in copd: secondary analysis of the uplift trial chronic 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proximal femur relationship of lung function to severity of osteoporosis in women association of osteoporotic vertebral compression fractures with impaired functional status the association of radiographically detected vertebral fractures with back pain and function: a prospective study vertebral fractures in patients with chronic obstructive pulmonary disease: the eolo study reduced pulmonary function in patients with spinal osteoporotic fractures the impact of severe exacerbations on quality of life and the clinical course of chronic obstructive pulmonary disease reduction of exacerbations by the pde4 inhibitor ro fl umilast-the importance of de fi ning different subsets of patients with copd azithromycin for prevention of exacerbations of copd ro fl umilast in moderate-to-severe chronic obstructive pulmonary disease treated with longacting bronchodilators: two randomised clinical trials antimicrobial peptides of multicellular organisms cutting edge: 1,25-dihydroxyvitamin d3 is a direct inducer of antimicrobial peptide gene expression toll-like receptor triggering of a vitamin d-mediated human antimicrobial response human cathelicidin (ll-37), a multifunctional peptide, is expressed by ocular surface epithelia and has potent antibacterial and antiviral activity activities of ll-37, a cathelin-associated antimicrobial peptide of human neutrophils the peptide antibiotic ll-37/hcap-18 is expressed in epithelia of the human lung where it has broad antimicrobial activity at the airway surface fighting infections with vitamin d vitamin d3 down-regulates monocyte tlr expression and triggers hyporesponsiveness to pathogen-associated molecular patterns vitamin d signaling in immunemediated disorders: evolving insights and therapeutic opportunities prevention of autoimmune diabetes in nod mice by 1,25 dihydroxyvitamin d3 the coming of age of 1,25-dihydroxyvitamin d(3) analogs as immunomodulatory agents immune modulatory treatment of trinitrobenzene sulfonic acid colitis with calcitriol is associated with a change of a t helper (th) 1/th17 to a th2 and regulatory t cell pro fi le evaluation of phagocytosis in rickets control of mycobacterium tuberculosis through mammalian toll-like receptors high doses of vitamin d to reduce exacerbations in copd: a randomized trial a 4-year trial of tiotropium in chronic obstructive pulmonary disease combined salmeterol and fl uticasone in the treatment of chronic obstructive pulmonary disease: a randomised controlled trial treatment of copd: the sooner the better? decreased histone deacetylase activity in chronic obstructive pulmonary disease vdr microrna expression and epigenetic silencing of vitamin d signaling in melanoma cells dna methylation-related vitamin d receptor insensitivity in breast cancer vitamin d and susceptibility of chronic lung diseases: role of epigenetics peripheral muscle weakness contributes to exercise limitation in copd pulmonary rehabilitation in chronic obstructive pulmonary disease exercise training in copd: how to distinguish responders from nonresponders higher 25-hydroxyvitamin d concentrations are associated with better lower-extremity function in both active and inactive persons aged > or =60 vitamin d status predicts physical performance and its decline in older persons effect of vitamin d on falls: a metaanalysis effect of vitamin d supplementation on muscle strength: a systematic review and meta-analysis role of vitamin d in skeletal muscle function osteomalacic myopathy low-dose vitamin d prevents muscular atrophy and reduces falls and hip fractures in women after stroke: a randomized controlled trial vitamin d and its role in skeletal muscle fall prevention with supplemental and active forms of vitamin d: a meta-analysis of randomised controlled trials oxidative capacity of the skeletal muscle and lactic acid kinetics during exercise in normal subjects and in patients with copd muscle fi ber type iix atrophy is involved in the loss of fat-free mass in chronic obstructive pulmonary disease induction of speci fi c proteins in cultured skeletal muscle cells by 1,25-dihydroxyvitamin d-3 analysis of the oxidative damage-induced conformational changes of apo-and holocalmodulin by dose-dependent protein oxidative surface mapping the effect of cholecalciferol in vivo on proteins and lipids of skeletal muscle from rachitic chicks vitamin d and human skeletal muscle the effects of whole-body vibration training and vitamin d supplementation on muscle strength, muscle mass, and bone density in institutionalized elderly women: a 6-month randomized, controlled trial vitamin d receptor genotypes in fl uence quadriceps strength in chronic obstructive pulmonary disease vitamin d status in patients with chronic obstructive pulmonary disease who participate in pulmonary rehabilitation vitamin d supplementation during rehabilitation in patients with chronic obstructive pulmonary disease: an intervention study prospective study of predictors of vitamin 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trial of vitamin d3 and calcium in multiple sclerosis randomized trial of vitamin d supplementation to prevent seasonal in fl uenza a in schoolchildren vitamin d supplementation reduces insulin resistance in south asian women living in new zealand who are insulin resistant and vitamin d de fi cient-a randomised, placebo-controlled trial vitamin d as supplementary treatment for tuberculosis: a double-blind, randomized, placebo-controlled trial 25-dihydroxyvitamin d3 and its analogues down-regulate cell invasion-associated proteases in cultured malignant cells 25(oh)2d3 is an autocrine regulator of extracellular matrix turnover and growth factor release via erp60 activated matrix vesicle metalloproteinases sputum matrix metalloproteases: comparison between chronic obstructive pulmonary disease and asthma upregulation of mmp-9 production by tnfalpha in keratinocytes and its attenuation by vitamin d childhood asthma may be a consequence of vitamin d de fi ciency the in utero effects of maternal vitamin d de fi ciency: how it results in asthma and other chronic diseases premature aging-like phenotype in fi broblast growth factor 23 null mice is a vitamin d-mediated process maternal vitamin d intake during pregnancy and early childhood wheezing early life origins of chronic obstructive pulmonary disease risk factors for chronic obstructive pulmonary disease in a european cohort of young adults vitamin d de fi ciency and chronic obstructive pulmonary disease: a vicious circle key: cord-321817-z9oj9nmv authors: cereda, emanuele; bogliolo, laura; lobascio, federica; barichella, michela; zecchinelli, anna lena; pezzoli, gianni; caccialanza, ricardo title: vitamin d supplementation and outcome in covid-19 patients from the outbreak area of lombardy, italy date: 2020-11-11 journal: nutrition doi: 10.1016/j.nut.2020.111055 sha: doc_id: 321817 cord_uid: z9oj9nmv • vitamin d has anti-inflammatory and immunoregulatory functions. • the involvement of vitamin in the pathophysiology of covid-19 is still not clear; • some studies support a link between vitamin d deficiency and worse covid-19 outcome; • vitamin d may also enhance macrophages activation and aberrant immune response; • in our study vitamin d supplementation was associated with a trend to higher mortality; • supplementation trials are crucial to clarify the role of vitamin d in covid-19. recent literature has substantially raised the interest in the immune-modulating properties of vitamin d against coronavirus disease 2019 (covid-19). although several viewpoints have been published, data supporting the hypothesized beneficial role are limited and controversial [1, 2] . consistently with systematic review reporting the protective role of 25-hydroxyvitamin d (25ohd) supplementation [3] , in a recent survey conducted in parkinson's disease (pd) patients, cases were more likely to be not-supplemented than unaffected patients [4] . the observation of lower mortality rates at lower degrees of latitude, along with other preliminary reports on the association between serum levels of 25ohd and the risk of having the disease or a critical outcome, have suggested that vitamin d could modulate the risk and mitigate the severity of covid-19 [1, 2, 5] . there is evidence that vitamin d has immunomodulatory functions and plays an anti-inflammatory role particularly in viral infections. it was also demonstrated to be inversely correlated to acute respiratory distress syndrome (ards) and increased levels of c-reactive protein [6] . on the other hand, the higher prevalence of 25ohd deficiency in many disease conditions is questionable according to a reversed causality hypothesis, as the underlying disease and related inflammatory background may negatively influence 25ohd metabolism, particularly of its binding protein, resulting in substantial bias in the assessment of its status [7, 8] . this is also suggested by differences in serum levels between pcr-positive and negative patients, which might not only be interpreted as a higher susceptibility to infection in patients with deficiency status [5, 9] . therefore, we aimed to evaluate whether vitamin 25ohd supplementation, which may be a better surrogate of real 25ohd status, is associated with prognosis in covid-19 patients from the italian outbreak area of lombardy. the study was approved by local institutional ethics committees and written informed consent was obtained from every patient. two sets of data collected prospectively during the outbreak of the pandemic in the north of italy were pooled and analyzed. the first consisted of covid-19 pd patients (group 1) and covid-19 pd caregivers (group 2) identified from a pool of 2693 pd patients (n=1486) and caregivers (n=1207) which were approached in a recent phone survey and interview conducted between march and may 2020 [4] . the second included consecutive covid-19 patients (group 3) admitted to a referral hospital between april and may 2020 (unpublished data). information on supplementation with 25ohd (defined as at least 25.000 iu/month in the last 3 months [800 iu/day]), weight status, comorbidities, serum 25ohd, covid-19 diagnosis and related hospitalization and in-hospital mortality were gathered by direct interview and validated through the consultation of institutional electronic charts and linkage to the regional register of healthcare data. in hospital inpatients, fasting venous serum samples were collected within 48 hours since admission for the assessment of 25ohd (chemiluminescence immunoassay [abbott diagnostics, lake forest, il, usa]). hospitalization and in-hospital mortality for covid-19 were the study endpoints. analyses were conducted using stata 16 (statacorp, college station, tx, usa). comparisons (supplemented vs. non-supplemented patients) of continuous variables were performed using parametric or non-parametric tests, while categorical variables were analyzed by the fisher's exact test. then, adjusted logistic regression was used to investigate the association between supplementation and study outcomes. overall, 324 covid-19 cases were included: group 1 (pd patients), 105 cases; group 2 (pd caregivers), n=92; group 3 (hospital inpatients), n=127. the characteristics of the study patients are summarized in table 1 died. the use of 25ohd supplements was not associated nor with hospitalization neither with inhospital mortality, although a trend to a 2-fold higher risk of death was found for supplements users, particularly after adjusting for potential confounders ( table 2 ). in our study, 25ohd supplementation was not associated with the severity of covid-19. on the other hand, a trend to a 2-fold higher mortality in users was found. vitamin d could boost mucosal defenses and protect against infections [1] [2] [3] [4] [5] [6] and it has been suggested to down-regulate the inflammatory burden contributing to acute respiratory distress syndrome and lung injury [2, 10, 11] , the main cause of death in covid-19 patients. enhanced ace2 expression is considered a protective factor in acute lung injury [10, 11] . vitamin d increases the expression of ace2 [6] , and this may apply not only to airway epithelium but also to other organs and monocyte-derived macrophages. however, ace2 is the binding site of sars-cov2 and increased ace2 expression may result in enhanced viral homing and organ damage, as well as in an aberrant innate immune response with hyper-activation of macrophages [11] , perhaps at least in highly complicated patients, as those admitted in our outbreak area. our data may appear in contrast with recent literature suggesting that higher serum 25ohd is associated with more favorable covid-19 outcomes, with lower progression of respiratory and to critical illness, as well as lower mortality rates [1, 2, 5, 12] , although no association has been also reported [13] . however, disease-related inflammation may negatively affect 25ohd metabolism, particularly of its binding protein, resulting in reduced circulating levels and assessment bias [7, 8] . in this perspective, also the timing of assessment in relation to the onset of symptoms could play a role [13] . it is with this background that we have decided to evaluate the association between supplementation rather than serum levels and outcome. nonetheless, we have evaluated s erum 25ohd in a subgroup of consecutive patient demonstrating that supplementation results in substantially higher and adequate circulating levels. therefore, although the potential utility of vitamin d in the prevention of respiratory tract infections is more substantial [3] , its benefits on covid-19 (prevention and management) still need to be clarified by appropriate intervention trials. we recognize the following limitations. first, a larger study population along with a multicenter participation would have resulted in increased statistical power and bias reduction. however, we were not able to perform a valid calculation of the sample size due to the emergency crisis and the heterogeneity in published data on outcome and use of supplements. indeed, we recognize that the emergency crisis was a source of bias itself as it is likely that only the worst cases have been hospitalized in our outbreak area. finally, in agreement with italian recommended dietary allowances [14] we have decided to define supplementation as an intake of at least 25.000 iu (800 iu/day) in the previous three months. it is not at all clear that supplements of <1000 iu/day are likely to make much difference compared to larger ones. however, the mean intake in supplemented patients was >54.000 iu (>1800 iu/day), resulting in adequate circulating levels in most patients assessed. in conclusion, 25ohd supplementation was not associated with hospitalization but appeared to be a risk factor for higher in-hospital mortality for covid-19. further studies are needed to clarify the role of vitamin d supplementation and status in modulating the severity of covid-19, as well as its prevention. does vitamin d status impact mortality from sars-cov-2 infection? med drug discov role of vitamin d in preventing of covid-19 infection, progression and severity vitamin d supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data covid -19 in parkinson's disease patients living in lombardy 25-hydroxyvitamin d concentrations are lower in patients with positive pcr for sars-cov-2 evidence that vitamin d supplementation could reduce risk of influenza and covid-19 infections and deaths vitamin d: a magic bullet or a myth? clin nutr a brief discussion of the benefit and mechanism of vitamin d supplementation on coronavirus disease 2019. curr opin clin nutr metab care association of vitamin d status and other clinical characteristics with covid-19 test results role of vitamin d in pathogenesis and severity of covid-19 infection the lung macrophage in sars-cov-2 infection: a friend or a foe vitamin d sufficiency, a serum 25-hydroxyvitamin d at least 30 ng/ml reduced risk for adverse clinical outcomes in patients with covid-19 infection impact of vitamin d deficiency on covid-19-a prospective analysis from the covild registry author contributions: dr. cereda had full access to all of the data in the study and take key: cord-263749-bbhh5xb1 authors: larenas-linnemann, désirée; rodríguez-pérez, noel; arias-cruz, alfredo; blandón-vijil, maría virginia; del-río-navarro, blanca e.; estrada-cardona, alan; gereda, josé e.; luna-pech, jorge a.; navarrete-rodríguez, elsy maureen; onuma-takane, ernesto; pozo-beltrán, césar fireth; rojo-gutiérrez, maría isabel title: enhancing innate immunity against virus in times of covid-19: trying to untangle facts from fictions date: 2020-10-09 journal: world allergy organ j doi: 10.1016/j.waojou.2020.100476 sha: doc_id: 263749 cord_uid: bbhh5xb1 introduction in the light of the current covid-19 pandemic, during which the world is confronted with a new, highly contagious virus that suppresses innate immunity as one of its initial virulence mechanisms, thus escaping from the first-line human defense mechanisms, enhancing innate immunity seems a good preventive strategy. methods without the intention to write an official systematic review, but more to give an overview of possible strategies, in this review article we discuss several interventions that might stimulate innate immunity and thus our defense against (viral) respiratory tract infections. some of these interventions can also stimulate the adaptive tand b-cell responses, but our main focus is on the innate part of immunity. we divide the reviewed interventions in: 1) lifestyle related (exercise, >7 hours sleep, forest walking, meditation/mindfulness, vitamin supplementation); 2) non-specific immune stimulants (letting fever advance, bacterial vaccines, probiotics, dialyzable leukocyte extract, pidotimod) and 3) specific vaccines with heterologous effect (bcg vaccine, mumps-measles-rubeola vaccine, i.e.). results for each of these interventions we briefly comment on their definition, possible mechanisms and evidence of clinical efficacy or lack of it, especially focusing on respiratory tract infections, viral infections and eventually a reduced mortality in severe respiratory infections in the intensive care unit. at the end a summary table demonstrates the best trials supporting (or not) clinical evidence. conclusion several interventions have some degree of evidence for enhancing the innate immune response and thus conveying possible benefit, but specific trials in covid-19 should be conducted to support solid recommendations. context of the covid-19 pandemic, extrapolated evidence from previous studies shows that regular, 128 moderate to vigorous exercise improves immune competency across the lifespan and may help to 129 reduce the frequency of upper-respiratory tract infections (urtis).(9, 10) importantly, this has been 130 observed also in older individuals (>65 year-olds) who regularly exercise, whose urtis incidence per 131 year has been inversely associated with the energy expenditure utilized during physical activity. conversely, some studies report that during prolonged periods of strenuous exercise (like marathons) 155 and after approximately 2 weeks following intense competitions, there is an immunodepression span 156 (the "open window" period), related to a higher rate of urti-like symptoms (mainly self-reported) vs. 157 those who undergo lower physical activity. (21, 22) this theory, attributed to the consequences of 158 psychological stress and excessive training,(23, 24) is however highly debated today in the light of a 159 better understanding of the variability in the intensity-related response to physical activity, which 160 depends largely on the functional capacity of the immune system, so up-to-date perceptions on this 161 topic tend to discard the concept of exercise-induced immunosuppression. in fact, it is widely accepted 162 that, when performed regularly, during and after exercise the immune system is in a heightened state of 163 immune surveillance and regulation.(25) 164 during the covid-19 quarantine it is important to stay active and to exercise regularly (gradually 165 increasing intensity), not only as a way to keep a healthy lifestyle, but also as an immunoprotective and 166 immunoregulatory activity. it is possible that the older adults (who are at higher risk of a severe sars-167 cov-2 infection) may obtain the greatest exercise-induced benefits to their immunological health. 168 169 2.2. forest bathing (shinrin yoku) 170 in a series of several, subsequent small studies, japanese investigators in cooperation with experts from 171 the stanford university have shown that walking in a forest seems to enhance nk cell activity, partly 172 stimulated by volatile substances produced by trees (particularly phytoncides: antimicrobial essential 173 oils from trees). the first experiment showed in vitro that phytoncides activate nk cell activity and 174 augment nk cell granules content.(26) then they confirmed this in peripheral blood lymphocytes of 175 subjects submitted to a prospective trial of a 3-day, 2-night trip to the forest including three 2-hour 176 walks.(27) in a third case-control trial they demonstrated that the effect was not related to the walking 177 j o u r n a l p r e -p r o o f 8 tour, as they compared the rise in nk-cell activity after a 3-day tour to a small city with that after a 3-day 178 tour to the forest. both tours included three 2-hour walks, but nk-cell activity was only enhanced after 179 the forest trip. moreover, nk-cell activity stayed elevated one week and still somewhat 30 days after the 180 tour. ( other studies have shown that sleep deprivation, both complete or only selective to the rapid eye 198 movement (rem) stage, modifies various components of the innate immune system, such as dendritic 199 cells (dcs) and the percentage of some subpopulations of t cells (cd4+, cd8+ and nk) and cytokine 200 levels (ifn-γ, tnf-α and il-1).(32-34) specifically, in a clinical study in women 77 hours of sleep 201 deprivation (total and rem phase) resulted in a proinflammatory state and affected the cellular immune 202 response, presenting changes in the production of ifns and in the phagocytic activity. sleep deprivation 203 also decreased lymphocytic blastogenesis, nk cell activity, and regulation of il-1 and il-2.(35) 204 j o u r n a l p r e -p r o o f 9 moreover, in the elderly, a sleep pattern with poor quality (self-reported) was related to increased levels 205 of il-6 and this association was not explained by other factors, such as depressive symptoms, stress or 206 loneliness, but exclusively by sleep disturbance as an independent factor.(36) 207 as for the clinical evidence, an adequate sleep pattern also appears to be beneficial in modulating the 208 adaptive immune response. spiegel the previously mentioned interventions are potential options that could improve the immune system 303 against sars-cov-2, but more evidence is required.(70) see table 2. 304 zinc is an essential trace element for the proper functioning of multiple biological processes within the 306 human body, and its contribution to immunity is not an exception.(72) 307 the complete mechanism by which zinc could decrease the number or severity of viral infectious 308 processes in general and of covid-19 in particular is not exactly understood yet; however, effects have 309 been observed on the binding of the viral agent to the mucosa and on its replication, as well as on the 310 regulation of the inflammatory process;(73) enhanced benefits have been hypothesized when co-311 administered with other medications such as (hydroxy)chloroquine that could function as a ionophore, 312 facilitating the entrance of zinc into the cells.(74) the human body's ability to store zinc is known to be 313 low; its deficiency compromises the immune system, as has been evidenced occasionally by thymic 314 atrophy, lymphopenia and altered lymphocyte responses. is not rock-solid yet, could be considered options that might help enhance the innate immune system 604 and thus worthwhile, especially, as most lack the risk for serious adverse events. together with the 605 techniques focusing on reduction of the viral load, such as social distancing, equipment for personal 606 protection and adequate hand hygiene, improving our first-line defense seems vital. finally, we add in 607 exercise regular exercise has a probable immunoprotective and immunoregulatory effect. older adults may obtain the greatest exercise-induced benefits for their immunological health. forest walks might be beneficial to boost innate immunity, particularly in times of a pandemic; evidence is limited, but there are no direct health-related safety issues. the potential benefit of adequate sleep patterns overweighs the low level of evidence available up to date mindfulness a constant program of a professionally guided meditation strategy could be beneficial to achieve an effective stress reduction and probably to reduce the burden of urtis, mainly in older adults the published study results so far have not been conclusive. subjects with vitamin deficiency would likely benefit most from supplementation. the intervention could be considered relatively safe a cochrane collaboration systematic review showed daily doses of 0.2mg reduced the duration of common cold. in ards patients very high iv doses might be beneficial. more data are needed. all 4 meta-analyzes have reported beneficial effects of zinc supplementation in children for the prevention of pneumonia. important to restore the redox balance. adverse effects are considered mild a modest efficacy of some probiotics (lactobacillus and bifidobacterium strains) was found in reducing the incidence and duration of viral respiratory infections though it might seem of benefit, evidence of the reduction of infections is very scarce and quality trials are lacking. with the use of pidotimod there is a lower recurrence of respiratory tract infections as compared to conventional treatment and less use of antibiotics we encourage to wait for the results of the ongoing rct before using bcg vaccination for the prevention of covid-19 heterothe immune stimulation produced by heterologous vaccines enhances the response to other pathogens, different from the one in the vaccine and was associated with reduced all-cause infant mortality (e.g. measles vaccine, bcg). influenza: the once and future pandemic estimation of the basic reproduction number, average incubation time, 615 asymptomatic infection rate, and case fatality rate for covid-19: meta-analysis and sensitivity analysis preliminary prediction of the basic 618 reproduction number of the wuhan novel coronavirus 2019-ncov sars coronavirus pathogenesis: host innate immune responses and viral 620 antagonism of interferon covid-19: consider 622 cytokine storm syndromes and immunosuppression is a "cytokine storm" relevant to covid-19? targets of t cell 626 responses to sars-cov-2 coronavirus in humans with covid-19 disease and unexposed individuals therapeutic potential of b-1a cells in covid-19 moderate to vigorous 630 physical activity and risk of upper-respiratory tract infection physical activity, 632 stress, and self-reported upper respiratory tract infection the symptomatology of upper respiratory tract 634 infections and exercise in elderly people exercise and the aging 636 immune system moderate exercise enhances the production of 638 interferon-gamma and interleukin-12 in peripheral blood mononuclear cells acute exercise 641 mobilises cd8+ t lymphocytes exhibiting an effector-memory phenotype exercise-induced redistribution of t 644 lymphocytes is regulated by adrenergic mechanisms t-regulatory cells exhibit 646 a biphasic response to prolonged endurance exercise in humans exercise and psychosocial factors 649 modulate immunity to influenza vaccine in elderly individuals signaling via trif contributes to a protective innate immune response to severe acute respiratory 653 syndrome coronavirus infection influence of 655 exercise training and age on cd14+ cell-surface expression of toll-like receptor 2 and 4 exercise amelioration of depression-like behavior in ovx mice 658 is associated with suppression of nlrp3 inflammasome activation in hippocampus does exercise increase the risk of upper respiratory 664 tract infections exercise, infection, and immunity exercise and airway injury in athletes debunking the myth of exercise-induced immune suppression: 669 redefining the impact of exercise on immunological health across the lifespan phytoncides (wood 672 essential oils) induce human natural killer cell activity forest bathing enhances 675 human natural killer activity and expression of anti-cancer proteins visiting a forest, but not 678 a city, increases human natural killer activity and expression of anti-cancer proteins effect of phytoncide 681 from trees on human natural killer cell function using psychoneuroimmunity against covid-19 galphas-684 coupled receptor signaling and sleep regulate integrin activation of human antigen-specific t cells number and function of circulating human antigen 687 presenting cells regulated by sleep rem sleep deprivation in rats results in 689 inflammation and interleukin-17 elevation effects of acute and chronic sleep loss on 691 immune modulation of rats the bidirectional relationship between sleep and immunity 694 against infections sleep disturbance and 696 older adults' inflammatory responses to acute stress effect of sleep deprivation on response to immunization. 698 sleep habits and susceptibility to the 700 common cold behaviorally assessed sleep and susceptibility 702 to the common cold psychological stress and susceptibility to the common cold relationships between mindfulness practice and levels of mindfulness, 706 medical and psychological symptoms and well-being in a mindfulness-based stress reduction program meditation or exercise for 709 preventing acute respiratory infection: a randomized controlled trial epidemic influenza and 711 vitamin d vitamin d and the intracrinology of innate immunity the interplay between vitamin d and viral 715 infections vitamin d in allergic disease: shedding light on a complex problem unexpected actions of vitamin d: new perspectives on the regulation of 719 innate and adaptive immunity vitamin d supplementation could reduce risk of influenza and covid-19 infections and deaths. 722 nutrients administration in ventilated intensive care unit patients: a pilot double blind randomized controlled 725 trial vitamin d and respiratory tract 727 infections: a systematic review and meta-analysis of randomized controlled trials vitamin d 730 supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of 731 individual participant data effect of vitamin d3 supplementation on 733 respiratory tract infections in healthy individuals: a systematic review and meta-analysis of 734 randomized controlled trials vitamin d supplementation for the prevention 736 of childhood acute respiratory infections: a systematic review of randomised controlled trials the 2011 report on 739 dietary reference intakes for calcium and vitamin d from the institute of medicine: what clinicians need 740 to know vitamin-d and covid-19: do deficient risk a poorer outcome? lancet diabetes 745 endocrinol vitamin d: deficiency, sufficiency and toxicity intravenous vitamin c for reduction of cytokines storm in acute respiratory 749 distress syndrome vitamin c is an essential factor on the anti-viral 751 immune responses through the production of interferon-alpha/beta at the initial stage of influenza a 752 virus (h3n2) infection vitamin c and common cold-induced asthma: a systematic review and statistical 754 analysis acid potentially regulates immune and inflammatory response associated 757 with coronavirus infections: a perspective from system biology analysis hypovitaminosis c and 759 vitamin c deficiency in critically ill patients despite recommended enteral and parenteral intakes. crit 760 care functional role of 763 dietary intervention to improve the outcome of covid-19: a hypothesis of work vascular endothelialitis, thrombosis, and angiogenesis in covid-19 modulation of host defence 768 against bacterial and viral infections by omega-3 polyunsaturated fatty acids flavonoids from houttuynia cordata attenuate 771 h1n1-induced acute lung injury in mice via inhibition of influenza virus and toll-like receptor signalling individual risk management 774 strategy and potential therapeutic options for the covid-19 pandemic the clinical benefits of chinese patent 776 medicines against covid-19 based on current evidence traditional chinese medicine in the treatment of 778 cov-2): a review and perspective pharmacological perspective: glycyrrhizin may be an efficacious therapeutic 781 agent for covid-19 the role of zinc in antiviral immunity zinc and 785 respiratory tract infections: perspectives for covid19 (review) improving the efficacy of chloroquine and hydroxychloroquine against 787 sars-cov-2 may require zinc additives -a better synergy for future covid-19 clinical trials zinc in human health: effect of zinc on immune cells role of zinc administration in prevention of childhood diarrhea 791 and respiratory illnesses: a meta-analysis low zinc status: a new risk factor for pneumonia in the 793 elderly? prevention of diarrhea and 795 pneumonia by zinc supplementation in children in developing countries: pooled analysis of randomized 796 controlled trials. zinc investigators' collaborative group zinc supplementation for the prevention of acute lower 798 respiratory infection in children in developing countries: meta-analysis and meta-regression of 799 randomized trials zinc lozenges may shorten the duration of colds: a systematic review fever and the thermal regulation of immunity: the immune 803 system feels the heat fever-like thermal conditions 805 regulate the activation of maturing dendritic cells conservation of 807 il-6 trans-signaling mechanisms controlling l-selectin adhesion by fever-range thermal stress from fever to immunity: a new role for igfbp-6? activation of the sympathetic nervous 814 system modulates neutrophil function the regulation of interleukin-6 implicates skeletal muscle as an integrative 816 stress sensor and endocrine organ human monocyte stimulation by 818 experimental whole body hyperthermia functional expression 820 of trpv channels in t cells and their implications in immune regulation the acute phase 822 protein haptoglobin regulates host immunity passive heat therapy protects 826 against endothelial cell hypoxia-reoxygenation via effects of elevations in temperature and circulating 827 factors community-acquired pneumonia in the elderly: association of 829 mortality with lack of fever and leukocytosis the effect of antipyretic 831 therapy upon outcomes in critically ill patients: a randomized, prospective study the value of sanitarium treatment in respiratory diseases washington, d.c.: review and 836 herald publishing assn antipyretic drugs in patients with fever and infection: literature review the effect of antipyretic 841 medications on mortality in critically ill patients with infection: a systematic review and meta-analysis population-level effects of suppressing fever therapeutic targeting of trained 846 immunity bcg-induced trained 848 immunity in nk cells: role for non-specific protection to infection trained immunity: a 852 program of innate immune memory in health and disease human dendritic cells activated with mv130 induce th1, th17 and il-10 responses via ripk2 and myd88 855 signalling pathways mv140, a 857 sublingual polyvalent bacterial preparation to treat recurrent urinary tract infections, licenses human 858 dendritic cells for generating th1, th17, and il-10 responses via syk and myd88 efficacy of whole-cell killed bacterial vaccines in preventing 864 pneumonia and death during the 1918 influenza pandemic sublingual therapeutic 866 immunization with a polyvalent bacterial preparation in patients with recurrent respiratory infections: 867 immunomodulatory effect on antigen-specific memory cd4+ t cells and impact on clinical outcome primary prevention of severe lower 870 respiratory illnesses in at-risk infants using the immunomodulator om-85 trained immunity in newborn 873 infants of hbv-infected mothers probiotics and the gut immune system: indirect regulation beneficial effects of 877 probiotic consumption on the immune system immunobiotic strains modulate toll-like receptor 3 agonist induced innate 879 antiviral immune response in human intestinal epithelial cells by modulating ifn regulatory factor 3 880 and nf-kappab signaling type i/ii 882 interferon in hiv-1-infected patients: expression in gut mucosa and in peripheral blood mononuclear 883 cells and its modification upon probiotic supplementation prospective study of probiotic 885 supplementation results in immune stimulation and improvement of upper respiratory infection rate probiotics and paraprobiotics in viral infection: 888 clinical application and effects on the innate and acquired immune systems probiotics and covid-19: one size does not fit all effectiveness of probiotics on the duration 893 of illness in healthy children and adults who develop common acute respiratory infectious conditions: a 894 systematic review and meta-analysis probiotics for preventing acute upper respiratory tract infections serum and 898 fecal profiles of aromatic microbial metabolites reflect gut microbiota disruption in critically ill patients: 899 a prospective observational pilot study is diet partly 901 responsible for differences in covid-19 death rates between and within countries? the cellular transfer of cutaneous hypersensitivity to tuberculin in man cd8+ t cells produce a 906 dialyzable antigen-specific activator of dendritic cells immune memory by dialyzable leukocyte extract from a cd8+ t cell line early differentiation of human cd11c(+)nk cells with gammadelta t cell activation properties 912 is promoted by dialyzable leukocyte extracts adjuvant treatment with a dialyzable leukocytes extract contributes to maintain 915 hpv-infected women free of low-grade cervical lesions dialyzable leukocyte extracts activate tlr-2 on monocytes the dialyzable leukocyte extract transferon(tm) inhibits tumor growth and brain 921 metastasis in a murine model of prostate cancer dialyzable leukocyte extract (transferon) administration in sepsis: 924 experience from a single referral pediatric intensive care unit innate immune system to improve survival traits in high risk pathogen scenarios adjuvant treatment using transfer factor 929 for bronchogenic carcinoma: long-term follow-up immunostimulants in respiratory diseases: focus on pidotimod effect of pidotimod on phagocytosis and 933 intracellular killing of staphylococcus aureus by human circulating polymorphonuclear neutrophils and 934 alveolar macrophages pidotimod stimulates natural killer cell 936 activity and inhibits thymocyte cell death pidotimod shows a chemokine-like activity through cxc chemokine receptor 3 (cxcr3) pidotimod promotes 941 functional maturation of dendritic cells and displays adjuvant properties at the nasal mucosa level immunomodulatory effects 944 of pidotimod in adults with community-acquired pneumonia undergoing standard antibiotic therapy pidotimod, an immunostimulant in pediatric recurrent respiratory 947 tract infections: a meta-analysis of randomized controlled trials safety and immunogenicity of early 949 bacillus calmette-guerin vaccination in infants who are preterm and/or have low birth weights: a 950 systematic review and meta-analysis treating bcg-induced disease in 952 children neonatal bcg vaccination against hospitalization due to respiratory infection and sepsis. clin infect 955 dis early bcg-denmark 957 and neonatal mortality among infants weighing <2500 g: a randomized controlled trial the efficacy of bacillus calmette-guerin 960 vaccinations for the prevention of acute upper respiratory tract infection in the elderly bcg 963 vaccination enhances the immunogenicity of subsequent influenza vaccination in healthy volunteers: a 964 randomized, placebo-controlled pilot study bcg vaccination protects 966 against experimental viral infection in humans through the induction of cytokines associated with 967 trained immunity bcg vaccine protection from severe coronavirus 969 disease 2019 (covid-19) sars-cov-2 rates in bcg-vaccinated and unvaccinated young 971 adults bcg-induced trained immunity: can it offer protection against covid-19? 973 heterologous immunity: role in natural and vaccine-induced resistance to 975 infections vaccination and heterologous immunity: 977 educating the immune system non-specific effect of vaccines: immediate 979 protection against respiratory syncytial virus infection by a live attenuated influenza vaccine. front 980 microbiol vitamin d supplementation and risk of respiratory tract infections: a meta-982 analysis of randomized controlled trials vitamin d supplementation for preventing infections 984 in children under five years of age effect of vitamin c 986 infusion on organ failure and biomarkers of inflammation and vascular injury in patients with sepsis 987 and severe acute respiratory failure: the citris-ali randomized clinical trial allergic rhinitis and its impact on asthma (aria) guidelines for allergic rhinitis based on grading of 991 recommendations assessment, development and evaluation (grade) and real-world evidence enteral omega-3 994 fatty acid, gamma-linolenic acid, and antioxidant supplementation in acute lung injury association of bcg, dtp, and measles containing vaccines with childhood mortality: systematic review. 998 days (enteral supplementation of n-3 fatty acids, γ-linolenic rice unlike the normal anti-viral response with increased ifn type i and iii and with it the activation of genes 1006 stimulated by ifn in adjacent cells and thereby increasing its anti-viral defense, the coronavirus has 1007 mechanisms that lower this anti-viral innate defense mechanism by interfering with ifn production and 1008 its effects. in addition, chemotactic molecules are released in a viral infection that attract macrophages 1009 (m∅), natural killer (nk) cells, and neutrophils. this reaction is not fully achieved during early infection 1010 with coronavirus, so the initial innate immune response appears incomplete and slow. after this first 1011 innate response, adaptive immunity is triggered via activation of dendritic cells (dc) that stimulate 1012 specific th1 lymphocytes, which in turn activate cytotoxic t cells (tccell) to eliminate infected cells, in 1013 the more advanced stages of the infection, along with plasma cell development and the production of 1014 antiviral igm and igg antibodies (not shown). however, in some patients with covid-19 at this stage a 1015 dysregulated activation of macrophages (i.e. by il6) is seen, causing the feared cytokine storm. 1016 the conversion of 25 ohd 2 to 1,25-(oh) 2 d 3 can be done directly in some cells of the immune system 1018 such as macrophages. the macrophage, like kidney cells, contains the enzyme 1-alpha hydroxylase that 1019 is capable of transforming vitamin d into its active form, calcitriol. 1020exposure of the macrophage to some pathogens induces the production of cp27b (step 1) (which allows 1021 25 ohd to enter the mitochondria for transformation into its active form 1,25-(oh) 2 d 3 ), (step 2) as well 1022 as vitamin d receptor (vdr) (step 3), which by binding to 1,25-(oh) 2 d3 increases the production of 1023 cathelicidin. (step 4) 1024the antimicrobial activity of vitamin d appears to be primarily dependent on the induction of 1025 cathelicidins, which perform numerous functions that enhance both innate and adaptive immunity; help 1026 improve the digestion process within the phagolysosome through a non-oxygen dependent mechanism 1027 key: cord-338140-p88fgojk authors: cervantes-pérez, enrique; cervantes-guevara, gabino; martínez-soto holguín, martha c.; cervantes-pérez, lorena a.; cervantes-pérez, gabino; cervantes-cardona, guillermo alonso; gonzález-ojeda, alejandro; fuentes-orozco, clotilde; ramírez-ochoa, sol title: medical nutrition therapy in hospitalized patients with sars-cov-2 (covid-19) infection in a non-critical care setting: knowledge in progress date: 2020-10-30 journal: curr nutr rep doi: 10.1007/s13668-020-00337-x sha: doc_id: 338140 cord_uid: p88fgojk purpose of review: as of 13 september 2020, almost 28 million confirmed cases of covid-19 including more than 920,000 deaths have been reported to the world health organization. the sars-cov-2 pandemic represents a potential threat to patients and healthcare systems worldwide. patients with the worst outcomes and higher mortality are reported to include older adults, polymorbid individuals, and malnourished people in general. the purpose of this review is to provide concise guidance for the nutritional management of individuals with covid-19 based on the current literature and focused on those in the non-icu setting or with an older age and polymorbidity, which are independently associated with malnutrition and its negative impact on mortality. recent findings: prolonged hospital stays are reported to be required for individuals with covid-19, and longer acute setting stays may directly worsen or cause malnutrition, with severe loss of skeletal muscle mass and function, which may lead to poor quality of life and additional morbidity. nutritional therapy is among the mainstay of therapeutic principles and one of the core contents of comprehensive treatment measures. summary: the current covid-19 pandemic is unprecedented. the prevention, diagnosis, and treatment of malnutrition should therefore be routinely included in the management of individuals with covid-19. numerous cases of pneumonia caused by a new virus, severe acute respiratory syndrome coronavirus 2 (sars-cov-2), were initially reported in wuhan, china, at the end of december 2019. since then, several thousand cases have been reported in china, and the disease has spread worldwide. as of 14 september 2020, almost 29 million confirmed cases of covid-19 including more than 920,000 deaths have been reported to world health organization [1] . although many comparisons to other coronavirus epidemics have been made, the potential impact of this coronavirus remains unknown. the purpose of this review is to summarize what is known about sars-cov-2 infection and provide possible and potential nutritional interventions on novel coronaviruses for clinicians. coronaviruses are widespread mainly by birds and mammals. the widest varieties of genotypes infect bats, but two subtypes infect humans: alpha and beta coronaviruses [2] . beta coronaviruses include severe acute respiratory syndrome coronavirus (sars-cov), middle east respiratory syndrome coronavirus (mers-cov), and the coronavirus variant that causes covid-19, all of which are members of the coronaviridae family of the order nidovirales [3] . currently, there is no registered treatment or vaccine for the disease. given the absence of specific treatment for this novel infection, there is a growing need to find alternatives and potential solutions to prevent and control the infection to improve both short-and long-term prognosis. older adults and polymorbid individuals suffering from chronic and acute disease conditions are at increased risk for poor outcomes and higher mortality following infection with the covid-19-causing virus. furthermore, identification of risk and the presence of malnutrition should be an early and routine step in the general evaluation of all patients. some scores, such as the nrs-2002 and must, have long been used in hospitalized patients or in specific disease scenarios for malnutrition risk screening. other tools include the mini nutritional assessment criteria, the subjective global assessment criteria, and the nutric score criteria for critically ill patients [4, 5] . recently, the glim (global leadership initiative on malnutrition) criteria proposed a two-step approach for malnutrition diagnosis by identifying patients at risk using validated screening tools (must, nrs-2002) with the possibility of grading the severity of malnutrition [6] . because poorer outcomes and higher mortality are reported in patients at risk for malnutrition, these considerations seem to be applicable to hospitalized patients at risk for covid-19 infection. nutritional status and preventing or treating malnutrition are the cornerstones to reducing complications and aiding patients who might be infected in the future. in addition, some gastrointestinal symptoms of sars-cov-2 infection, including nausea, vomiting, and diarrhea, might compromise food intake and nutrient absorption [7, 8] . based on the spanish influenza pandemic of 1918-1919 causing acute illness in 30% of the world's population and 40 million deaths and, more recently, the 2009 influenza pandemic, all these retrospective analyses of available data revealed that the disease severity depended on viral and host factors. some of these included cellular and humoral immune responses and nutritional and genetic aspects. in addition, a current challenge is not only to take care of those affected by undernutrition but also people living with obesity. some viral responses, such as virus-specific cd8+ t cells, have been described in obese patients [9] . the diet counseling process in sars-cov-2-infected patients could be performed using electronic devices when possible to limit the exposure of the clinician. patients at nutritional risk should receive nutritional support as soon as possible, particularly increasing protein intake by consuming oral nutrition supplements (onss) [9] . if available, indirect calorimetry must be used to assess energy needs. some other alternatives are prediction equations or weight-based formulae. for polymorbid patients aged > 65 years, the consumption of a total of 27 kcal/kg body weight per day is recommended. in the case of severely underweight polymorbid patients, 30 kcal/ kg body weight per day should be considered. a goal of 30 kcal/kg body weight should be slowly achieved to avoid refeeding syndrome [4, 10] . protein needs are estimated according to age, nutritional status, physical activity level, disease status, and tolerance. geriatric patients should receive 1 g protein per kg body weight/day and > 1 g per kg body weight/day in polymorbid patients to prevent body weight loss and hospital readmission and reduce the risk of complications [4, 10] . regarding the nonprotein calorie (fat and carbohydrate) ratio, in participants with no acute respiratory distress syndrome, a ratio of approximately 30:70 is recommended. patients who are not at risk for malnutrition should maintain adequate protein (1.5 g/d) and nonprotein caloric (25-30 kcal/d) intake [11•] (fig. 1 ). trace elements are fundamental for the correct functioning of our bodies, and they are especially important in disease states. there are no specific recommendations about how to supplement trace elements in individuals with covid-19, but here is some evidence about the benefits of these minerals and their importance in the proper functioning of the body; these minerals should be supplemented in case of deficiency [12••] . key dietary components such as vitamins a, c, d, e, iron, zinc, s e l e n i u m , a n d c o p p e r h a v e w e l l -e s t a b l i s h e d immunomodulatory effects, with benefits in infectious disease. some of these nutrients have also been shown to have a potential role in the management of covid-19 [13] . selenium is an essential trace element for mammalian redox biology [14] . the nutritional status of the host plays a very important role in the defense against infectious diseases. nutritional deficiency impacts not only the immune response but also the viral pathogen itself. dietary selenium deficiency, which causes oxidative stress in the host, can alter a viral genome so that a normally benign or mildly pathogenic virus can become highly virulent in the deficient host under oxidative stress conditions [15] . this is because selenium could assist a group of enzymes that, in concert with vitamin e, work to prevent the formation of free radicals and prevent oxidative damage to cells and tissues [16] . zinc is a trace dietary mineral and is important for the maintenance and development of immune cells of both the innate and adaptive immune systems [17] . zinc has the potential to increase the cytotoxic activity of nk cells, which can attack cells that exhibit abnormal or unusual proteins in the plasma membrane. when nk cells kill infected cells, the microorganisms inside are released and destroyed through phagocytosis by neutrophils and macrophages, which migrate to infected areas. the zinc also acts as an anti-inflammatory agent, nausea, vomiting, diarrhea, abdominal pain and severe fatigue which impair food intake and absorption side effects of antiviral drugs (such as chloroquine) should be used to provide at least 400 kcal/day including 30 g or more of protein/day and shall be continued for atleast one month. • if oral intake is expected to be impossible for more than three days or expected to be <50% of energy requirements for more than one week. • infusion of formula into the stomach via 10-12 fr feeding nasogastric tube. • initiate with low dose 10-20 ml/h of hypocaloric or trophic, advancing to full dose enteral nutrition slowly over the first week. • early parenteral nutrition should be initiated as soon as possible in the high-risk patient for whom early gastric enteral nutrition is not feasible or not achieve target. • start early during hospitalization within 24-48 hours, especially for older and polymorbid patients. maintaining immune tolerance as it induces the development of regulatory t cells and mitigates the development of proinflammatory th17 and th9 cells, besides being involved in antibody production, particularly igg. zinc deficiency is very common, particularly within the elderly population, and there are difficulties in the diagnosis because of the lack of clinical signs and reliable biochemical indicators, as well as the absence of a specific and reliable biomarker of zinc status [18] . increased intracellular zn2+ concentrations are known to efficiently impair the replication of several rna viruses. a study in 2010 reported that coronavirus replication can be inhibited by increased zn2+ levels. the concentration of 2um zn2+ inhibited the replication of sars-coronavirus (sars-cov) in cell culture [19] . iron is a nutrient with diverse implications in covid-19. first, it is well-known the importance of iron for the correct functioning of the immune system. however, it is also wellestablished that iron-containing enzymes are essential for the completion of virus replication process, particularly coronaviruses. thus, it has been pointed out that iron chelation could be an alternative adjuvant strategy to treat individuals with covid-19, via manipulation of key iron regulators (still needs further research), venous injection, or oral administration of iron chelators [20] . iron participates in several immune processes and is an essential component for some enzymes involved in crucial activities of immune cells. due to its structure, iron also plays an important role as a mediator of oxidative stress situations (acting as a redox catalyst) and exerts powerful antimicrobial effects by forming highly toxic hydroxyl radicals for infection agents. therefore, deficient or suboptimal levels of iron are associated with decreased killer efficiency of nk cells and lymphocytes as well as with compromised cytokine production [21, 22] . therefore, both iron uptake disturbances and metabolism are implicated in virulence of airway hospital-acquired infection and chronic respiratory infections. in contrast, excessive iron levels can generate harmful cellular toxicity, so their serum levels must be well regulated [23] . in the case of covid-19, iron metabolism is clearly disrupted in sars-cov-2infected patients, especially in patients hardest hit by the disease; consequently, anemia or hyperferritinemia are typical manifestations of hospitalized individuals with covid-19. therefore, optimal iron status may be crucial for better disease prognosis. populations with lower iron status could be more prone to suffer a mild to severe (or critical) symptomatology of covid-19 and the fact of monitoring patient iron levels has been proposed as a potential early marker to predict covid-19 severity and mortality [23, 24] . it is now known that patients with nutritional deficiencies are at the highest risk for ventilatory complications. patients with malnutrition should ensure sufficient supplementation with vitamins and minerals. part of the general treatment for viral infections is vitamin supplementation to improve the outcome of the disease [25] . many host defenses depend on the adequate supply of this vitamin, and it has been reported that vitamin a supplementation reduces the morbidity and mortality of different infectious diseases. it has also been reported that supplementation with vitamin a offers some protection against the complications of other life-threatening infections [26] [27] [28] . the mechanism by which vitamin a and retinoids inhibit measles replication is upregulating elements of the innate immune response in uninfected bystander cells, making them refractory to a productive infection during subsequent rounds of viral replication [29] . vitamin a could be a promising option for the treatment of this novel coronavirus. each vitamin b has its special functions; vitamin b2 (riboflavin) plays a role in the energy metabolism of all cells. keil et al. reported that vitamin b2 and uv light effectively reduced the titer of mers-cov in human plasma products [30] . vitamin b3 significantly inhibited neutrophil infiltration into the lungs with a strong anti-inflammatory effect during ventilator-induced lung injury when tested against staphylococcus aureus infections [31, 32] . vitamin b6 is needed for protein metabolism and participates in over 100 reactions in body tissues. as a shortage of b vitamins may weaken the host immune response, b vitamins could be supplemented to sars-cov-2-infected patients to enhance their immune system. vitamin c is known as an essential antioxidant and enzymatic co-factor for physiological reactions, such as hormone production, collagen synthesis, and immune potentiation, also improves vasopressor synthesis, improves endovascular function, and exerts epigenetic immunologic modifications [33] . vitamin c may also function as a weak antihistamine agent to provide relief from flu-like symptoms such as sneezing, a runny or stuffy nose, and swollen sinuses [34] . humans are unable to synthesize vitamin c; therefore, they must acquire vitamin c from dietary sources. the therapeutic use of vitamin c to prevent inflammatory hyperactivation in myeloid and lymphoid cells has been explored. high doses of vitamin c act as a prooxidant for immune cells but as an antioxidant for lung epithelial cells, though there is not enough evidence to suggest its routine use [35, 36] . recently registered on clincialtrials. gov (identifier: nct04264533), a new clinical trial to investigate vitamin c infusion for the treatment of severe 2019-ncov-infected pneumonia began in wuhan, china. this is one of the first rcts to test the effects of iv vitamin c in patients infected with this virus. in this trial, the investigators will treat 140 patients with a placebo control or intravenous vitamin c at a dose of 24 g/day for 7 days. they will assess requirements for mechanical ventilation and vasopressor drugs, organ failure scores, icu length of stay, and 28-day mortality [37] . in addition to its role in maintaining bone integrity, vitamin d also stimulates the maturation of many cells, including immune cells [38] . several reviews have considered the way in which vitamin d reduces the risk of microbial infection and death, and those mechanisms can be grouped into three categories: physical barrier, cellular natural immunity, and adaptive immunity. vitamin d helps maintain tight cell junctions, gap junctions, and adherens junctions. many healthy adults have been reported to have low levels of vitamin d, mostly at the end of the winter season [39] . the association of vitamin d deficiency with respiratory tract infections and lung injury has been widely reported. indeed, the usage of vitamin d agonists has shown effectiveness ameliorating the aforementioned conditions. the striking overlap between risk factors for severe covid-19 and vitamin d deficiency, including obesity, older age, and black or asian ethnic origin, has led some researchers to hypothesize that vitamin d supplementation could hold promise as a preventive or therapeutic agent for covid-19. there are good reasons to postulate that vitamin d favorably modulates host responses to severe acute respiratory syndrome coronavirus 2 (sars-cov-2), both in the early viremic and later hyperinflammatory phases of covid-19 [40] . furthermore, previous investigations have demonstrated that high-dose supplementation of vitamin d (250,000-500,000 iu/day) is safe and effective in improving the health status of mechanically ventilated critically ill patients (enhancing the capacity of blood for oxygen transport and increasing hemoglobin levels), which resulted in shorter hospital stays [20] . vitamin e is a lipid-soluble vitamin that plays an important role in reducing oxidative stress by binding to free radicals as an antioxidant. vitamin e is a major fat-soluble antioxidant that scavenges peroxyl radicals and terminates the oxidation of polyunsaturated fatty acids (pufas). dietary interventions with vitamin e at supplemental levels have been shown to enhance cell-mediated and humoral immune responses in various species of animals [41] . increased lymphocyte proliferation, immunoglobulin levels, antibody responses, natural killer (nk) cell activity, and interleukin (il)-2 production have been reported with vitamin e supplementation [42, 43] . in humans, the effects of vitamin e on the natural incidence of infectious diseases have been determined in several studies. m a n y s t u d i e s h a v e p r o v i d e d e v i d e n c e th a t t h e immunostimulatory effects of vitamin e confer improved resistance to infections. however, the magnitudes of the effects were rather small, and in some studies, positive effects were only observed in subgroups of participants. a recent study found a lower incidence of pneumonia among participants taking 50 mg/day of vitamin e for a median of 6 years [44] . long-chain polyunsaturated fatty acids (pufas) are important mediators of inflammation and adaptive immune responses. omega-3 and omega-6 pufas predominantly promote anti-inflammatory and proinflammatory effects. they are precursors of resolvins/protectins and prostaglandins/leukotrienes, respectively. it has been shown that protectin d1, an omega-3 pufa-derived lipid mediator, could markedly attenuate influenza virus replication via the rna export machinery. omega-3 pufas, including protectin d1, could be considered a potential intervention for covid-19 [12••] . t cells, b cells, the complement system, and phagocytes compose the immune system. all these are the primary defense barriers against infections, and any weaknesses could be detrimental to the host, and malnutrition can result in weaknesses of these defensive barriers. it is also known that healthy immune systems are one way of defending against viral infections [45] . numerous scientific papers have been published explaining the role of nutrition in the immune system describing the declining t cell function attributed to thymic involution and subsequent reduced output of naïve t cells [46] , aging-associated inflammation [47] , and poor micronutrient status-a bidirectional relationship between infection/ immunity and nutrition, whereby changes in one of these components can impact the other [48] . gombart et al. identified that potential synergistic relationships of micronutrients are required to meet the complex needs of the immune system, including relationships among vitamins a, d, c, e, b 6 , and b 12 ; folate; copper; iron; zinc; and selenium, but the largest body of evidence comes from vitamins c and d and zinc [49••] . according to previous sars and mers treatments, some general treatments, including nutritional interventions, are very important to enhance the host immune response. every effort should be made to avoid or limit underfeeding in individuals with covid-19, and proper nutritional strategies should ensure adequate support for hospitalized patients to reduce or prevent consequences in malnourished populations. moreover, given the rapid transmission of covid-19, clinicians are working against the clock to find potential possible solutions. unfortunately, rigorous trials are currently lacking, and most of what we know is based on observational evidence or previous studies conducted in other populations with infectious diseases. conflict of interest the authors have no relevant interests to declare. human and animal rights and informed consent this article does not contain any studies with human oranimal subjects performed by any of the authors. have been highlighted as: • of importance •• of major importance 1. who coronavirus disease (covid-19) dashboard. geneva: world health organization bats and coronaviruses middle east respiratory syndrome espen guideline on clinical nutrition and hydration in geriatrics espen guidelines on definitions and terminology of clinical nutrition glim criteria for the diagnosis of malnutrition -a consensus report from the global clinical nutrition community covid-19: gastrointestinal manifestations and potential fecal-oral transmission epidemiological and clinical characteristics of 99 cases of 2019 novel coronavirus pneumonia in wuhan, china: a descriptive study back to the future: lessons learned from the 1918 influenza pandemic espen guidelines on nutritional support for polymorbid internal medicine patients a rapid advice guideline for the diagnosis and treatment of 2019 novel coronavirus (2019-ncov) infected pneumonia this guideline established that the patient should be given supportive treatment to ensure sufficient energy intake and balance for water, electrolytes, acid-base levels, and other internal environment factors this review summarized all the potential interventions for covid-19 infection according to previous treatments of sars and mers. it suggested that all the potential interventions be implemented to control the emerging covid-19 if the infection is uncontrollable and proposed to verify the nutritional status of covid-19 immune-boosting role of vitamins d, c, e, zinc, selenium and omega-3 fatty acids: could they help against covid-19? selenium and human health selenium, selenoproteins and viral infection review: micronutrient selenium deficiency influences evolution of some viral infectious diseases zinc and immunity: an essential interrelation the key role of zinc in elderly immunity: a possible approach in the covid-19 crisis zn(2+) inhibits coronavirus and arterivirus rna polymerase activity in vitro and zinc ionophores block the replication of these viruses in cell culture key aspects in nutritional management of covid-19 patients prediction of combustion induced vibration in rocket motors cell iron status influences macrophage polarization current state of evidence: influence of nutritional and nutrigenetic factors on immunity in the covid-19 pandemic framework serum iron level as a potential predictor of coronavirus disease 2019 severity and mortality: a retrospective study espen expert statements and practical guidance for nutritional management of individuals with sars-cov-2 infection importance of vitamin a deficiency in pathology and immunology of viral infections vitamin a and immunity to viral, bacterial and protozoan infections vitamin a supplements ameliorate the adverse effect of hiv -1, malaria, and diarrheal infections on child growth retinoids inhibit measles virus through a type i ifn -dependent bystander effect inactivation of middle east respiratory syndrome coronavirus (mers-cov) in plasma products using a riboflavin-based and ultraviolet light-based photochemical treatment c/ebpepsilon mediates nicotinamide -enhanced clearance of staphylococcus aureus in mice nicotinamide exacerbates hypoxemia in ventilator -induced lung injury independent of neutrophil infiltration targeting cancer vulnerabilities with high-dose vitamin c nutrients and their role in host resistance to infection the emerging role of vitamin c as a treatment for sepsis clinical trials on drug repositioning for covid-19 treatment a new clinical trial to test high-dose vitamin c in patients with covid-19 vitamin d insufficiency among free -living healthy young adults optimal nutritional status for a well-functioning immune system is an important factor to protect against viral infections vitamin d for covid-19: a case to answer? the role of vitamin e in immunity high dietary intakes of vitamin e and cellular immune functions in rats long-term feeding of high vitamin e diet improves the decreased mitogen response of rat splenic lymphocytes with aging vitamin e administration may decrease the incidence of pneumonia in elderly males feeding the immune system thymic regeneration: teaching an old immune system new tricks inflammaging: a new immune-metabolic viewpoint for age-related diseases immune function and micronutrient requirements change over the life course this review established that the inflammatory response bridges the gap between innate and adaptive immunity, and is regulated by vitamins a, c, e, and b6, as well as iron, zinc, and copper. adaptive immune responses encompassing cell-mediated and humoral immunity publisher's note springer nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations key: cord-333248-5342lyeu authors: elenius, varpu; palomares, oscar; waris, matti; turunen, riitta; puhakka, tuomo; rückert, beate; vuorinen, tytti; allander, tobias; vahlberg, tero; akdis, mübeccel; camargo, carlos a.; akdis, cezmi a.; jartti, tuomas title: the relationship of serum vitamins a, d, e and ll-37 levels with allergic status, tonsillar virus detection and immune response date: 2017-02-24 journal: plos one doi: 10.1371/journal.pone.0172350 sha: doc_id: 333248 cord_uid: 5342lyeu background: tonsils have an active role in immune defence and inducing and maintaining tolerance to allergens. vitamins a, d, and e, and antimicrobial peptide ll-37 may have immunomodulatory effects. we studied how their serum levels were associated with allergy status, intratonsillar/nasopharyngeal virus detection and intratonsillar expression of t celland innate immune response-specific cytokines, transcription factors and type i/ii/iii interferons in patients undergoing tonsillectomy. methods: 110 elective tonsillectomy patients participated. serum levels of vitamins a, 25(oh)d, and e, ll-37 and allergen-specific ige as well as nasopharyngeal/intratonsillar respiratory viruses were analyzed. the mrna expression of ifn-α, ifn-β, ifn-γ, il-10, il-13, il-17, il-28, il-29, il-37, tgf-β, foxp3, gata3, rorc2 and tbet in tonsils were analyzed by quantitative rt-pcr. results: the median age of the patients was 16 years (range 3–60), 28% of subjects had atopy, and 57% carried ≥1 respiratory virus in nasopharynx. detection of viruses decreased by age. higher vitamin a levels showed borderline significance with less viral detection (p = 0.056). higher 25(oh)d was associated with less allergic rhinitis and atopy (p < 0.05) and higher vitamin e with less self-reported allergy (p < 0.05). in gene expression analyses, 25(oh)d was associated with higher il-37, vitamin a with higher ifn-γ and vitamin e with less il-28 (p < 0.05). ll-37 was associated with less foxp3, rorc2 and il-17 in tonsils (p < 0.05). conclusions: vitamin d and e levels were associated with less allergic disorders. vitamin a was linked to antiviral and vitamin d with anti-inflammatory activity. ll-37 and was linked to t regulatory cell effects. epidemiologic and multiple observational studies suggest that deficiencies of vitamins a, d and e may be associated with development of asthma and allergic disorders [1] [2] [3] [4] . it was found in several studies that vitamin a deficiency is associated with a higher risk of asthma [5] [6] [7] , but randomized trials with vitamin a supplementation were less supportive [8, 9] . prospective studies have shown that vitamin d supplementation reduces the risk of recurrent respiratory infections, virus-induced wheezing and asthma exacerbations although some of the studies have shown conflicting results [10] [11] [12] [13] [14] . vitamin d is known to induce antimicrobial peptide ll-37, which has anti-viral, -bacterial and -fungal effects [15] . maternal vitamin e intake during pregnancy has been negatively associated with wheezing and eczema in children of atopic mothers [16, 17] . we determined serum levels of vitamins a, d, and e and antimicrobial peptide ll-37 in patients undergoing tonsillectomy. tonsils are the first contact point of the immune system to various infectious agents, food and aeroallergens [18] and they have an active role in inducing and maintaining tolerance to various allergens [19] . however, it is not known how they regulate these functions. we studied how serum vitamins and antimicrobial peptide ll-37 levels and allergic and tonsillar diseases were associated with direct in vivo detection of respiratory viruses and t cell subset-related transcription factors, cytokines as well as type i, ii and iii interferons in tonsils. human tonsil samples were obtained from 110 elective tonsillectomy patients (table 1) from satakunta central hospital, pori, finland, from april 2008 to march 2009 and biobanked. tonsillectomy was done according to clinical indications. written informed consent was obtained from the study patients and/or their guardians. the ethics committee of turku university hospital approved the study. all patients filled a standard questionnaire to obtain information of their allergic diseases and respiratory symptoms. atopy was defined as positive immunoglobulin e (ige) antibody (>0.35 ku/l) to any of the following allergens: codfish, cow's milk, egg, peanut, soybean, wheat, cat, dog, horse, birch, mugwort, timothy, cladosporium herbarum or dermatophagoides pteronyssinus (phadiatop combi 1 , phadia, uppsala, sweden). animal sensitization was defined as positive ige antibodies to cat, dog, horse or dermatophagoides pteronyssinus. birch, mugwort, timothy and cladosporium herbarum were considered as pollen aeroallergens. the eczema was defined as atopic eczema, if a child was atopic and had typical symptoms that included pruritus, typical morphology and chronicity of atopic eczema (hanifin and rajka diagnostic criteria for atopic dermatitis). vitamins and ll-37 vs. allergy, virus infection and tonsillar immune response serum samples were taken before surgery. tonsillectomy was performed according to clinical routine. tonsil tissue was immediately cut in 3-4 mm cubes in sterile conditions, stored in rnalater rna stabilization reagent (qiagen, hilden, germany), incubated at 2-8˚c until the next working day and stored in -80˚c after removal of the non-absorbed reagent [20] . the nasopharyngeal aspirate samples were obtained during the operation using a standardized procedure as previously described [21] . both nasopharyngeal aspirate and sera were stored in -80˚c before analyses. retinoic acid (vitamin a) and alpha tocopherol (vitamin e) levels were determined by highperformance liquid chromatography (hplc) in the vita laboratory, helsinki, finland. serum total 25(oh)d measurement was done using an immunoassay (abbott architect, chicago, usa) and ll-37 was measured using elisa (hycult biotech, uden, the netherlands), both in massachusetts general hospital, boston, usa. bioavailable levels of 25(oh)d were estimated using additional serum measurements (d-binding protein and albumin) and published formulae [22] . serum specific ige levels against common airborne and food allergens were determined by using a fluoroenzyme immunoassay (cut-off for specific allergens 0.35 ku/l; immunocap, phadia, uppsala, sweden) in turku university hospital, turku, finland. [20] . a nasopharyngeal aspirate sample was suspended into 1 ml of pbs, and nucleic acid was isolated from 550 μl of the suspension using nuclisense easymag automated nucleic acid extractor (biomerieux, boxtel, the netherlands) with on-board lysis. intratonsillar samples (approximately 300 μg each) were homogenized and the total rna was isolated from tonsil tissues as previously described [20] . reverse transcription was performed with the revert aid m-mulv reverse transcriptase (fermentas, st. leon-rot, germany) using random hexamer primers according to the manufacturers protocol. we analyzed intratonsillar mrna expression levels of the cytokines and transcription factors related to t subsets cells relevant to allergic responses as well as type i/iii interferons related to antiviral responses ( table 2) . gene expressions of ifn-α, ifn-β, ifn-γ, il-10, il-13, il-17, il-28, il-29, il-37, tgf-β, foxp3, gata3, rorc2 and tbet were analyzed by quantitative real-time as previously described [20] . elongation factor 1α (ef1α) was used as a housekeeping gene. data are shown as relative expressions, which show 2 -(δct) values multiplied by 10 4 , where δct corresponds to the difference between the ct value for the gene of interest and ef1α. statistical analysis continuous variables were described as means (sds) or medians (interquartile ranges) when appropriate, and categorical variables as frequencies and percentages. the subjects with and without serum samples were compared using mann-whitney u-test and chi-square test. correlations were calculated using spearman rank-order correlations coefficients due to mainly skewed distributions. the associations of serum levels of vitamins and ll-37, allergy status and virus detection with intratonsillar cytokine and transcription factor expressions were analyzed using univariable and age-adjusted linear regression. the modifying effects of age (<16 vs. !16 years) and indication of tonsillectomy (recurrent tonsillitis vs. hypertrophic tonsils) on the associations were also examined. analyses were also adjusted for smoking. before analyses, vitamin d and ll-37 levels and gene expression values were log transformed because of positively skewed distributions. statistical significance was established at the level of p < 0.05. statistical analyses were done using sas system for windows (version 9.4, sas institute inc. cary, nc, usa). initially, tonsil samples were available from 143 patients and analysed for clinical data, nasopharyngeal/intratonsillar virology and intratonsillar gene expression. serum samples were available from 110 subjects of these, who were included in the study. the subjects without serum samples did not differ from the analytic cohort in regard to age, sex, allergy or nasopharyngeal/intratonsillar virus detection (all p > 0.1). the median age of the study subjects was 16 years (range 3-60) and 45% were males. main indications for tonsillectomy were hypertrophic tonsils (43%), recurrent tonsillitis (38%), other indications (5%) or a combination of these indications (14%) ( table 1 ). altogether, 51% of patients had self-reported allergy and 28% had atopy, 27% had physician-diagnosed allergic rhinitis, 14% physician-diagnosed atopic eczema and 12% physician-diagnosed asthma (table 1) . seventeen % of patients had respiratory symptoms on the operation day (table 1) . the median level for serum vitamin a was 1. both vitamin a and e levels increased by age (p <0.0001) (fig 1a and 1b) , but serum bioavailable 25(oh)d levels slightly decreased by age (p = 0.02) (fig 1c) . total 25(oh)d and antimicrobial peptide ll-37 levels did not vary by age (p = 0.57) (s1 fig) . in the nasopharyngeal aspirates, 57% of the patients had at least one virus and 23% had 2 or more viruses (fig 2a) . rhinovirus (47%) was the most prevalent virus, followed by bocavirus-1 (14%), adenovirus (9%), enteroviruses (8%), coronavirus (6%) and other viruses (<3% each) (fig 2a) . in tonsils, 25% of patients had at least one virus and 6% had 2 or more viruses (fig 2a) . bocavirus-1 was detected in 7%, adenovirus and enteroviruses in 8%, and parainfluenza and rhinovirus in 4% of the tonsils (fig 2a) . virus detection rates strongly decreased by age (both p < 0.0001) (fig 2b) . overall virus prevalence was 100% in children under age 5 years, but only 13% after 40 years of age ( fig 2b) . in age-adjusted analyses, higher vitamin a tended to associate with less nasopharyngeal virus detection (p = 0.056) (fig 3a) . lower bioavailable 25(oh)d levels were associated with allergic rhinitis (p = 0.046) ( fig 3b) and lower vitamin e levels with self-reported allergy (p = 0.0086) (fig 3c) . lower total (p = 0.036) and bioavailable 25(oh)d (p = 0.0031) levels were associated with atopy (fig 3d and 3e, respectively) . no other significant associations were found. age or indication for tonsillectomy did not effect on these clinical associations. in age-adjusted analysis, we observed that higher bioavailable 25(oh)d levels were associated with higher expression levels of newly discovered anti-inflammatory cytokine il-37 (p = 0.024) ( fig 4a) and higher vitamin a levels were associated with higher expression of ifn-γ (p = 0.043) (fig 4b) . higher vitamin e levels were associated with lower il-28 expression (p = 0.016) (fig 4c) . in addition, higher serum antimicrobial peptide ll-37 levels were associated with lower expression of intratonsillar foxp3 (p = 0.011) (fig 4d) , rorc2 (p = 0.015) ( fig 4e) and il-17 (p = 0.044) (fig 4f) . no other significant associations were found between serum levels of vitamins and ll-37 and the "immune activation/regulatory" cluster of cytokines and their transcription factors in tonsils. age, smoking or indication for tonsillectomy did not have modifying effects on the mrna expression associations. this study provides new insights into connections between serum levels of vitamins a, d, and e and antimicrobial peptide ll-37 and several important outcomes: allergy, respiratory virus detection and tonsillar immune responses. we found that higher bioavailable 25(oh)d levels were associated with lower prevalence of allergic rhinitis and atopy, higher vitamin e levels with lower prevalence of self-reported allergy, and higher vitamin a showed borderline significance for an association with less respiratory virus detections. in line with this finding, we found that higher vitamin a levels were associated with higher intratonsillar expression of ifn-γ. also, higher serum bioavailable 25(oh)d levels were associated with higher intratonsillar expression of novel anti-inflammatory cytokine il-37, which is known to suppress immune responses, regulate t-reg development and induce tolerance [23] . exacerbations of childhood and adult asthma are often caused by viral infection [24] . it is generally accepted that, low or deficient innate and adaptive immune responses may contribute to the morbidity of viral infections [25] . we show that multiple viruses exist in nasopharynx and tonsils in relatively asymptomatic patients. less vitamin a was associated with less ifn-γ and tendency for more viral detection, which may partly explain the association previously seen with vitamin a deficiency and asthma exacerbations [1] . the inverse association between vitamin a levels and virus detection in our study is interesting since multiple observational studies have shown that vitamin a deficiency is associated with a higher risk of asthma and wheezing [5-7, 26, 27] . vitamin a has been shown to enhance treg activity via foxp3 and inhibit th17 development via retinoid orphan receptor γt (rorγt) [28] [29] [30] [31] , but we did not find any significant association between serum vitamin a levels and intratonsillar antiviral/immunoregulatory gene expression, except for ifn-γ. ifn-γ is a critical molecule in immune system with multiple functions, mostly related to th1 response against bacterial, viral and fungal infections [32] . vitamin d has beneficial pleiotropic effects on both the innate and adaptive immune system [33] . high vitamin d levels during maternity are associated with less childhood wheezing [34] [35] [36] [37] and vitamin d deficiency appears to contribute to increased susceptibility to infections and wheezing [12, 38, 39] . prospective studies have shown that vitamin d supplementation reduces the risk of recurrent respiratory infections, virus-induced wheezing and asthma exacerbations [12] . even though multiple studies suggest that vitamin d has beneficial effects on the immune defense and on allergic disease, the exact mechanisms are not well defined. our finding of the positive association with higher vitamin d status and higher intratonsillar expression of anti-inflammatory cytokine il-37 might partly explain some of these results. il-37 is an anti-inflammatory cytokine which suppresses immune responses and inflammation [23] . vitamin d is also known to enhance the expression of antimicrobial peptide cathelicidin, often referred in its active form as ll-37 [15] . ll-37 is not only an endogenous antibiotic peptide that destroy bacteria, virus and fungi, but can also act as an immune modulator [40] . we found that higher serum ll-37 levels were associated with lower intratonsillar expression of il-17 and its transcription factor rorc2, both needed to th17 cell development [41] , as well as lower expression of foxp3, a transcription factor known to induce treg cells [41, 42] . in our study cohort, serum ll-37 levels tended to increase with vitamin d levels, but this correlation did not reached statistical significance (s2 fig). our patients did not have acute infection at the time of operation and collection of blood samples. it might be that without acute infection, serum ll-37 levels are not elevated. this data may suggest that a critical balance appear to lie between ll-37 expression due to infections and th17 and treg cell development. vitamin e levels have been shown to associate with th1 and th17 development [43] . our data shows that serum higher vitamin e levels were associated with less self-reported allergy. in agreement with this finding, maternal vitamin e intake during pregnancy has been associated with less wheezing and eczema in children [16, 17] . we found weak or no associations between serum vitamin e levels and the expression of cytokines or transcription factors in tonsils. strengths of our study are simultaneous measurement of multiple vitamins and a novel antimicrobial peptide ll-37, comprehensive viral and atopy characterization and complete clinical data of over 100 patients. statistical analyses were conducted carefully and adjusted for age, smoking and indication for tonsillectomy. according to a previous report from our group, indication for operation, mainly tonsil hypertrophy or recurrently infected tonsils, do not play a role in expression of studied genes [20] . however, we do not have yet any mechanistic data to understand how these regulatory networks crosstalk. in summary, our study provides new evidence suggesting that vitamin a may have antiviral effects. also, our study suggests potentially important roles for vitamin d and antimicrobial peptide ll-37 in th17 and treg cell regulation and development of allergic disease. clinically, our study suggests that vitamin d may promote anti-inflammatory mechanisms. further studies are needed to understand the crosstalk between regulatory networks in allergy and viral infections. nutrients and foods for the primary prevention of asthma and allergy: systematic review and meta-analysis prenatal intake of vitamins and allergic outcomes in the offspring: a systematic review and meta-analysis vitamin d insufficiency and asthma in a us nationwide study prenatal, perinatal, and childhood vitamin d exposure and their association with childhood allergic rhinitis and allergic sensitization vitamin a status in children with asthma serum vitamin a 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responses to allergens antioxidant intake in pregnancy in relation to wheeze and eczema in the first two years of life mucosal immune response in the ear, nose and throat induction and maintenance of allergen-specific foxp3+ treg cells in human tonsils as potential first-line organs of oral tolerance distinct regulation of tonsillar immune response in virus infection respiratory picornaviruses and respiratory syncytial virus as causative agents of acute expiratory wheezing in children bioavailable vitamin d is more tightly linked to mineral metabolism than total vitamin d in incident hemodialysis patients from il-2 to il-37: the expanding spectrum of anti-inflammatory cytokines epidemiology of respiratory viruses in patients hospitalized with near-fatal asthma, acute exacerbations of asthma, or chronic obstructive pulmonary disease interactions between innate and adaptive immunity in asthma pathogenesis: new perspectives from studies on acute exacerbations plasma lycopene and antioxidant vitamins in asthma: the plava study vitamin a deficiency alters airway resistance in children with acute upper respiratory infection all-trans retinoic acid mediates enhanced t reg cell growth, differentiation, and gut homing in the face of high levels of co-stimulation retinoic acid increases foxp3+ regulatory t cells and inhibits development of th17 cells by enhancing tgf-beta-driven smad3 signaling and inhibiting il-6 and il-23 receptor expression stat6 inhibits tgf-beta1-mediated foxp3 induction through direct binding to the foxp3 promoter, which is reverted by retinoic acid receptor th17 responses in chronic allergic airway inflammation abrogate regulatory t-cell-mediated tolerance and contribute to airway remodeling clinical implications of interferon-γ genetic and epigenetic variants what is new in vitamin d maternal vitamin d intake during pregnancy and early childhood wheezing maternal intake of vitamin d during pregnancy and risk of recurrent wheeze in children at 3 y of age maternal vitamin d status and childhood asthma, wheeze, and eczema: a systematic review and meta-analysis infant respiratory tract infections or wheeze and maternal vitamin d in pregnancy: a systematic review low serum 25-hydroxyvitamin d levels are associated with increased risk of viral coinfections in wheezing children is vitamin d deficiency a marker of severity of wheezing in children? a cross-sectional study antimicrobial peptides and the skin immune defense system mechanisms of peripheral tolerance to allergens vitamin a and retinoic acid in t cell-related immunity the role of retinoic acid in tolerance and immunity key: cord-032544-2yrqjw1o authors: haroon, sabrina-wong-peixin; tai, bee-choo; ling, lieng-hsi; teo, lynette; davenport, andrew; schurgers, leon; teo, boon-wee; khatri, priyanka; ong, ching-ching; low, sanmay; yeo, xi-er; tan, jia-neng; subramanian, srinivas; chua, horng-ruey; tan, swee-yaw; wong, weng-kin; lau, titus-wai-leong title: treatment to reduce vascular calcification in hemodialysis patients using vitamin k (trevasc-hdk): a study protocol for a randomized controlled trial date: 2020-09-04 journal: medicine (baltimore) doi: 10.1097/md.0000000000021906 sha: doc_id: 32544 cord_uid: 2yrqjw1o introduction: end stage renal failure patients on hemodialysis have significant vascular calcification this is postulated to be related to sub-clinical vitamin k deficiency, which is prevalent in hemodialysis patients. vitamin k deficiency result in the failure of the matrix gla protein (mgp) to undergo carboxylation. mgp is a natural local inhibitor of vascular calcification and the lack of functional carboxylated mgp may contribute to increase vascular calcification. vitamin k supplement should therefore correct this anomaly and decrease the rate or severity of vascular calcification in this population of patients on long-term maintenance hemodialysis. our study seeks to evaluate the prevalence and the progression of vascular calcification in a cohort of maintenance hemodialysis patients. it will also evaluate the efficacy of vitamin k supplementation in reducing the progression of vascular calcification in this group of patients. methods: this will be a single-center randomized, prospective and open-label interventional clinical trial of end stage renal failure patients on hemodialysis. we aim to recruit 200 patients. eligible patients will be randomized to either the standard care arm or active treatment arm. active treatment arm patients will receive standard care plus supplementation with oral vitamin k2 isoform 360 mcg 3 times weekly for a total duration of 18 months. primary outcome measured will be absolute difference in coronary artery calcification score at 18-month between control and intervention arms. secondary outcomes will be to compare absolute difference in aortic valve calcification, percentage of patients with regression of coronary artery calcification of at least 10%, absolute difference in aortic and systemic arterial stiffness, mortality from any cause and major adverse cardiovascular over the same period. discussion: evidence of successful regression or retardation of vascular calcification will support the conduct of larger and longer-term trials aimed at reducing cardiovascular disease mortality and major adverse cardiovascular events in this high-risk population using a safe and inexpensive strategy trial registration: clinicaltrials.gov nct02870829. registered on 17 august 2016 – retrospectively registered, https://clinicaltrials.gov/ct2/show/nct02870829 national university hospital's institutional review board (2015/01000) it is well recognized that coronary artery calcification (cac), a form of vascular calcification (vc), occurs at a much higher rate in the dialysis population compared to age-matched populations without chronic kidney disease (ckd). [1, 2] studies have also confirmed a positive association of cac with adverse outcomes in this population. [2] there is a dose relationship reported between the cac score and cardiovascular disease (cvd) mortality; the higher the score, the higher the mortality risk. [3] given that one major cause of death and hospitalization in the dialysis population is cvd, these observations may be of critical importance in efforts to reduce cvd mortality and morbidity. [2] two distinct types of vc are reported in the ckd population. [4] atherosclerotic calcification occurs in the intimal layer and is associated with atherosclerosis and potentially rupture of unstable plaque, leading to acute myocardium infarction and stroke. various animal models and human studies support the development of this form of vc in uremic and nonuremic settings. another form, medial calcification (calcific arteriosclerosis) is also commonly observed in ckd and uremia, and contributes to a higher cvd mortality in this population due to increased vascular stiffness with loss of vessel elasticity, resulting in increased cardiac afterload, progressive left ventricular hypertrophy and ultimately, heart failure and arrhythmia. [5] in the general non-ckd population, established risk factors for cac are older age, diabetes, hypertension, dyslipidemia and smoking, while in ckd, dialysis vintage is an additional risk factor. [6] several factors unique to the uremic population appear to increase the risk of medial calcification which differs in pathogenesis from intimal atherosclerotic calcification, being typically non-inflammatory in nature. [7] hyperphosphatemia, elevated calcium-phosphate product and use of calcium-containing phosphate binders (a reflection of excess calcium loading) have been associated with an increased risk of vc in the ckd population. 1,25 (oh)2 vitamin d3 supplementation, commonly employed to suppress parathyroid hormone in ckd, has also been implicated as a cause of vc. [8] other promoters (such as bone morphogenetic protein and osteocalcin) and inhibitors (such as matrix gla protein and fetuin-a) of vc have been identified. [9] [10] [11] [12] while their role in clinical management remains to be established, these proteins are potential therapeutic targets in ckd-associated vc. given that cvd is a major cause of mortality and morbidity in the ckd population, there has been intense interest in therapies to reduce cvd events. statin therapy has proven very successful in reducing major adverse cardiac events (mace). however, two large prospective randomized controlled trials could not demonstrate a significant reduction in cvd, non-fatal myocardial infarction and non-fatal stroke in patients on hemodialysis assigned to potent hypolipidemic agents (namely atorvastatin and rosuvastatin) despite significant ldl-cholesterol lowering compared to placebo. [13, 14] control of other cvd risk factors which can accelerate vc is routine in the management of patients on dialysis. however, there are no randomized trials investigating the effect of glycemic or blood pressure control on vc or cac in this population. the latest frontier in the battle against vc and cvd in the dialysis population is ckd-mineral bone disorder which is characterized by excessive calcium loading, phosphate retention and hyperparathyroidism. [15] in vitro as well as population studies support the role of each of these factors, alone or in combination, in the genesis of vc. [16, 17] therefore, efforts to reduce vc in the ckd population have focused on correcting the altered bone mineral homeostasis. reduction in calcium load is achieved by using lower dialysate calcium concentrations and non-calcium containing phosphate binders such as sevelamer. [18, 19] lowering of serum phosphate in ckd patients with elevated phosphate level is also key to reducing the onset and severity of vc. there has been some success with the use of calcimimetics in reversing vc in dialysis patients. [20] however, the largest randomized controlled trial to date did not show a statistically significant reduction in cvd outcomes in hemodialysis patients with moderate to severe hyperparathyroidism receiving cinacalcet over a median of 21 months compared to placebo. [21] the cellular and molecular events leading to calcium deposition in vascular tissue are highly regulated. animal and molecular studies have demonstrated that vitamin k can influence the development and progression of vc, via its involvement in the carboxylation of matrix gla protein (mgp). [22, 23] mgp, a protein synthesized by vascular smooth muscle cells, functions as a natural local inhibitor of vc [24, 25] but becomes functional only after vitamin k2-dependent carboxylation. mgp deficient mice have been shown to develop massive calcification and do not survive beyond 6 weeks of birth. [26] many dialysis patients may have sub-clinical vitamin k deficiency, possibly related to dietary restriction, as evidenced by the high level of dephosphorylated undercarboxylated mgp (dp-ucmgp) measured in this population. [27] oral vitamin k supplementation can enhance carboxylation of mgp and lower plasma dp-ucmgp. vitamin k1 (phylloquinone) is the usual dietary source of vitamin k. vitamin k2 is derived from enterocyte conversion of vitamin k1 or from indigenous gut bacteria production [28] although 1 food source, natto (soybean fermented using bacillus subtilis) has a very high content of vitamin k2. [29] the precise dose of vitamin k needed in the physiological state to activate all vitamin k dependent proteins is not entirely clear. there is also an inherent divergent use of vitamin k1 for carboxylation of vitamin k dependent proteins in the liver such as for coagulation factors, preferentially over its utilization in the periphery (extra-hepatic), as a mean of ensuring adequacy of certain essential protein function for short-term survival. [30] this preferential triaging of the utilization of vitamin k may result in significant reduction of vitamin-k dependent carboxylation of extra-hepatic vitamin-k proteins even when modest deficiency exists. peripheral carboxylation of vitamin k dependent proteins such as mgp are dependent on long-chain isoforms of vitamin k2 (menaquinones). one such isoform with proven efficacy in decreasing dp-ucmgp levels is menaquinone-7 (mk-7). [27] a recent randomized trial reporting 1-year outcome of vitamin k2 supplementation in hemodialysis patients found no effect on aortic calcification despite reduction in dp-ucmgp. [31] there are still two ongoing trials evaluating the impact of vitamin k1 supplementation on vc in end stage renal failure (esrf) and 1 with vitamin k2 supplementation in esrf patients with non-valvular atrial fibrillation. [32] [33] [34] all these trials were conducted in the caucasian populations. as vitamin k intake will vary according to diet, there may well be differences between european and north american patient groups compared to those from asia. to our knowledge, there are no similar studies in asians. the proposed "treatment to reduce vascular calcification in hemodialysis patients using vitamin k" (trevasc-hdk) study is therefore timely. the primary objective of trevasc-hdk is to evaluate the effect of vitamin k2 (mk-7) supplementation on the progression of cac in esrf patients on hd. we hypothesize that oral mk-7 will enhance carboxylation of mgp, lower levels of dp-ucmgp and reduce cac and/or aortic vascular calcification (avc) in the hd population. secondary outcomes of interest include the effects of mk-7 on avc (known to be correlated with cac), aortic stiffness (which is determined by aortic calcification rather than atherosclerotic plaque burden) and clinical outcomes (see "study outcomes" below). trevasc-hdk will also provide the first local data on the prevalence and severity of cac or avc in patients on maintenance hd, as well as the natural history of calcification in those not receiving mk-7. study design trevasc-hdk is a single-center randomized, prospective and open-label interventional clinical trial of esrf patients on hd. the study protocol was developed in adherence to the good clinical practice guidelines and standard protocol items: recommendations for intervention trials. [35] the study is performed according to the ethical standards of the national university hospital's institutional review board (2015/01000) on clinical trials with human subjects and with the helsinki declaration of 1975 (and as revised in1983). the trial is registered at clinicaltrials.gov (nct02870829). national university hospital is 1 of the major academic tertiary hospitals in singapore caring for esrf patients. potential study subjects are identified from the haemodialysis and nephrology clinics in this hospital (single site). all patients will continue to receive standard of care dialysis at their usual satellite dialysis units during the conduct of this study. patients meeting the inclusion and exclusion criteria will be invited to participate and written informed consent obtained for those willing to participate. consented subjects will attend a screening visit (v0) where a multislice computed tomogram will be performed to assess their degree of cac. as the main objective is to investigate the effects of intervention on vc, pre-existing cac indicated by a baseline cac score of ≥ 30 agatston units is mandated for entry into the trial. this threshold also excludes patients with mild cac which is unlikely to progress in the relatively short window of observation. [19] other inclusion and exclusion criteria are outlined in table 1 . consent is taken by study team co-investigator after detailed explanation of purpose, benefit and risk of the study. witness is required for patient signing informed consent in chinese and malay language. patients are informed the right to withdraw consent and participation at any time during the study period. eligible patients will be randomized to either the control arm (standard care) or active treatment arm (standard care plus supplementation with vitamin k2 isoform mk-7). the dose of mk-7 chosen is oral 360 mcg 3 times weekly for a total duration of 18 months. patients will be randomly allocated into control and intervention arms in a 1:1 fashion using random permuted blocks of size 4 and 6. the randomization will be stratified by diabetes status. the sequence of treatment allocation will be generated using the ralloc module of the stata software. randomization will be performed by clinical trial unit coordinator during office hour. to ensure that the study is adequately powered, we have estimated the sample size based on the primary outcome of absolute difference in cac score at 18-months between the control and intervention arms, assuming mean cac scores at 18months of 1005 and 786 respectively as reported by block et al. [19] applying natural logarithmic transformation to cac scores due to skewed distribution, this corresponds to a mean logcac of 6.91 and 6.67, respectively. further assuming a common sd of 0.55, power of 80%, 2-sided level of significance of 5% and equal allocation between the 2 treatment arms, a minimum sample size of 170 in total, or 85 per arm will be required. accounting for an attrition rate of 15%, we will recruit a total of 200 patients. randomized patients will be scheduled for a first visit (v1) within 4 weeks from v0, during which blood will be drawn for dp-ucmgp, the biomarker of vitamin k deficiency, and aortic stiffness measured. patients who are randomized to the treatment arm will receive mk-7 during this visit. during the treatment phase of 18 months, the primary physician will review the study subjects at intervals of 2-6 months as per standard care. the research coordinator will contact these subjects every month to motivate compliance with active treatment, and perform pill counts during clinic visits to verify adherence. the investigational product (vitamin k2 isoform mk-7) will be stored in accordance to manufacturer's recommendations at investigational medicine unit, national university hospital singapore. active treatment will end after 18 months, following which an end of study visit (v2) will be scheduled for all study subjects within 4 weeks. during v2, blood will be obtained for dp-ucmgp, and measurement of aortic stiffness and cac/avc scores repeated. the trial flow chart and study schedule is summarized in figures 1 and 2 respectively. the criteria for termination of the study are: (1) withdraw consent (2) completion of the study protocol at 18 months (3) renal transplantation (4) mortality (5) requirement for vitamin k antagonist (6) allergy to mk-7 (7) parathyroidectomy (8) started on any vitamin k supplementation outside of clinical trial blood will be collected in an ethylenediaminetetraacetic acid tube, processed after withdrawal and stored at à80°c as plasma before analysis at coagulation profile bv, maastricht university, the netherlands. in brief, plasma dp-ucmgp levels will be determined in a single run using the commercially available ivd ce-marked chemiluminescent inaktif mgp assay on the ids-isys system (ids, boldon). both patient samples and internal calibrators will be incubated with magnetic particles coated with murine monoclonal antibodies against dp-mgp, acridiniumlabelled murine monoclonal antibodies against ucmgp, and an assay buffer. the magnetic particles will be captured using a magnet and washed to remove any unbound analyte. trigger reagents will be added; the resulting light emitted by the acridinium label is directly proportional to the level of dp-ucmgp in the sample [36] 3.7. measurement of aortic stiffness conduit arterial or aortic stiffness will be assessed using applanation tonometry (sphygmocorvx, atcor medical, west ryde, nsw, australia) [37] by trained technicians blinded to treatment assignment. this non-invasive technique uses a highfidelity pressure transducer applied lightly over the carotid, femoral and radial arteries to obtain the following: the right carotid to right femoral path length will be measured in a straight line with a tape ruler, and 80% of this distance used as pulse wave traveled distance (d). [38] right carotid-femoral transit time will be obtained by subtracting the time (t) between onset of the electrocardiographic r wave and the foot of the carotid pulse and the time between the r-wave and the femoral pulse, each averaged from 8 to 10 sequential waveforms. cfpwv will be calculated as d/t and expressed as m/s. two measurements will be taken and averaged. if their difference exceeds 0.5 m/s, a third measurement will be made and the median value taken. 3.7.2. b. pulse wave analysis. this is performed on the arm not used for vascular access. from the radial artery waveform obtained by the high-fidelity tonometer, the sphygmocorpx system reconstructs the aortic pressure waveform using a transfer function. [39, 40] this waveform depends on left ventricular ejection, as well as the timing and amount of wave reflection from branch points or areas of impedance mismatch which are determined by aortic stiffness and arteriolar tone. [41] from the aortic waveform, central systolic, diastolic, mean and pulse pressures are obtained. aortic augmentation index (ai) will be calculated as the increment in pressure from the first systolic shoulder of the ascending aortic pressure wave to the peak of the second, late systolic shoulder, expressed as a percentage of the pulse pressure. aortic ai is also normalized to a heart rate of 75 beats/min to facilitate comparison. calcium scoring will be performed using a high-pitch multislice computed tomogram scanner. all patients should have a resting heart rate <100 beats/min. scan length is defined by a scout view from the arch to the diaphragm. for all scans, the extent of cac and avc will be assessed using both volume and agatston scores by 2 radiologists unaware of treatment assignment. the volume score will be determined by the calculated volume of calcified plaques with a density of > 130 hounsfield units and a minimum size of 0.5 mm 3 based on isotropic interpolation. [42] the agatston score will be calculated by multiplying the weighted value and size of the calcified areas as previously described. [43] 3.8. study outcomes control and intervention arms will be compared for the following outcomes of interest: primary outcome absolute difference in cac score at 18-months secondary outcomes (1) absolute difference in avc score at 18-months (2) percentage of patients with regression of cac of ≥ 10% over 18-month (3) absolute difference in cfpwv and ai at 18-months (4) mortality from any cause within the study period (5) mace defined as non-fatal myocardial infarction, heart failure, acute coronary syndrome, need for coronary revascularization, non-fatal stroke, significant peripheral vascular disease (gangrene, amputation, need for revascularization) within the study period (6) difference in plasma levels of dp-ucmgp at 18 months (7) vascular access events, including clotting requiring insertion of a new dialysis catheter, declotting or exchange of an existing catheter, and vascular intervention during the study period. the absolute difference in cac and avc scores at 18-months between control and intervention arms will be compared using the t-test following log transformation. adjustment for baseline cac and avc scores respectively will be made via the analysis of covariance. likewise, the effects of mk-7 supplementation on dp-ucmgp level, cfpwv and ai at 18 months will be compared between the 2 groups using the t-test, with adjustment made for the respective baseline covariates via analysis of covariance. the percentage of patients with regression of cac score of ≥ 10% at 18 months from baseline will be compared between control and intervention arms via the x 2 test. the effect of treatment will be quantified using the odds ratio estimate and its associated 95% confidence interval. the logistic regression analysis will be used to account for potential confounders where applicable. for all-cause mortality and mace, the time to the respective event is defined as the time from randomization to the time when the event of interest occurred. subjects in whom an event was not observed will be censored at 18-months. the kaplan-meier survival analysis and the log-rank test will be used to compare the survival distributions between the control and intervention groups. the effect of treatment will be quantified using the hazard ratio estimate and its associated 95% confidence interval. further, the cox proportional hazards regression stratified by diabetes will be used to account for potential confounders where applicable. all statistical evaluations will be made assuming a 2-sided test at the 5% level of significance based on an intention-to-treat analysis. 3.9.1. monitoring. data will be reviewed monthly by study team to ensure accuracy and completeness. both primary investigator and study team will perform data and safety monitoring. in addition, national university hospital research office team will perform data monitoring and quality checks at least twice a year. the primary investigator will be required to submit trial report to health science authority regarding the progress of the trial and onsite monitoring visit are performed if necessary. 3.9.2. adverse event reporting and harm. timely, accurate and complete reporting and analysis of safety information from clinical studies are crucial for the protection of patients and are mandated by regulatory agencies. unanticipated problems involving risks to subjects or others are events that include any incident, experience, or outcome (including adverse events) that are unexpected, related or possibly related to research participation, with risk of harm and are part of the safety reporting structure as mandated by our instuitional review board. data collected on adverse events will be evaluated thoroughly and if necessary, may lead to changes in the conduct of the study or even termination or suspension of the study. due to the nature of the study being open-label in design, the unanticipated problems involving risks to subjects or others events and adverse events will be reported formally only for patients on the active treatment group. those randomized to the control group will have all adverse events recorded (but not reported) for the purpose of comparison with the active treatment group. patients and the public were not involved in the development of this study protocol. the conception of the study and the haroon et al. medicine (2020) 99:36 medicine development of the protocol were all investigator initiated and driven. results will be disseminated to all study participants after study completion. results will also be made known to the wider medical community through peer-reviewed publications and presentations at national and international meetings. majority (80%) of our local esrf patients are on hemodialysis. [44] similar to many developed countries, cardiovascular diseases have now replaced infection as the major cause of mortality and mortality among end stage renal failure patients. [45] the difference in pathophysiology of cardiovascular disease in renal failure patients compared to general population have raised questions about possible interventions or management. kidney diseases improving global outcomes has recommended routine screening of vascular calcification for dialysis patients, but the subsequent plan of management remains unclear and controversial. [46] should we still adopt the general measures to reduce cardiovascular risk and refer to cardiology for intervention? actual intervention with coronary stenting and angioplasty in addition to being invasive may not be as useful compared to the general population. as such we felt that it was important to study valvular calcification and vascular stiffness as this correlate closely with coronary artery calcification and has been reported to have an impact on morbidity and mortality for our patient. [47, 48] recent evidence emphasizes the possibility of vitamin k playing a key role in vascular calcification. not surprising, end stage renal failure patients are known to be deficient in various nutrients due to dietary restrictions and losses with dialysis. we have designed the trevasc-hdk trial to investigate the importance of vitamin k on the natural history of cv disease, and whether intervention with vitamin k2 can modulate progression. vitamin k preparations, predominantly vitamin k1, are currently available as supplements over the counter in health food shops and pharmacies, but currently not prescribed to patient as medication. in our study vitamin k2 is prescribed orally and to be administered 3x/week. as this is a clinical trial to study the role of vitamin k, it was registered with our local health science authority for reporting and monitoring purposes. as vitamin k2 has greater biological activity, and conversion of vitamin k1 to k2 can vary between individuals, we chose to administer vitamin k2. the advantages of our study, in addition to the primary outcome, we will be able to provide additional information about the possible vitamin k deficiency in our patients' diet. a previous short-term study demonstrated that oral administration of vitamin k2 led to a change in dp-ucmgp activity, in a dose response manner. [49] we chose the lowest dose of vitamin k2 (360 mcg 3x/week) used in this dose finding study which had an effect on dp-ucmgp activity, as we have no current data about vitamin k intake in our population and our asian patients have a lower body surface area compared to europeans, and no data on taking vitamin k2 for 18 months. although patients enrolled into the study are managed primarily by their own primary nephrologist and there should be minimal variation of management in both groups, as clinicians adhere to agreed management protocols. our trial is important even if the study is negative as we will have more insight into the baseline level and role of vitamin kin asian patients as well as provide us with the magnitude and progression of calcification in our multiethnic hd population. trevasc-hdk will be the first randomized, controlled trial to test the hypothesis that oral vitamin k2 supplementation can reduce vc in an asian hd population. evidence of successful regression or retardation of vc will support the conduct of larger and longerterm trials aimed at reducing cvd mortality and mace in this high-risk population using a safe and inexpensive strategy. the latest protocol version is 2.0. the revised protocol includes changes in the designated laboratory to process the biomarkers, additional tests done and change in inclusion criteria to include patients with lower dialysis vintage of 12 months. our study started the first patient recruitment on august 10, 2016. as we did not reach recruitment target within the initial specified time period, we extended the recruitment period and last patient recruited was on july 6, 2017. all patients have completed their final visit and we are currently pending biomarker analysis. due to current covid-19 pandemic, we anticipate a slight delay in trial closure. the current projection is that the trial should be completed by late 2020. coronary-artery calcification in young adults with end-stage renal disease who are undergoing dialysis medicine (2020) 99:36 www.md-journal cardiac calcification in adult hemodialysis patients. a link between end-stage renal disease and cardiovascular disease? impact of high coronary artery calcification score (cacs) on survival in patients on chronic hemodialysis vascular calcification: the killer of patients with chronic kidney disease mechanistic insights into vascular calcification in chronic kidney disease arteriosclerosis, vascular calcifications and cardiovascular disease in uremia vascular calcification in chronic kidney disease: an update the circulating calcification inhibitors, fetuin-a and osteoprotegerin, but not matrix gla protein, are associated with vascular stiffness and calcification in children on dialysis chronic kidney disease circulating calciprotein particles and extracellular vesicles promote vascular calcification: a role for grp (gla-rich protein) vascular calcification: from pathophysiology to biomarkers inhibition of bone morphogenetic 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patients: a 1-year follow-up randomized trial vitamin k1 to slow vascular calcification in hemodialysis patients (vitavask trial): a rationale and study protocol inhibiting the progression of arterial calcification with vitamin k in hemodialysis patients (ipack-hd) trial: rationale and study design for a randomized trial of vitamin k in patients with end stage kidney disease multicenter randomized controlled trial of vitamin k antagonist replacement by rivaroxaban with or without vitamin k2 in hemodialysis patients with atrial fibrillation: the valkyrie study spirit 2013 explanation and elaboration: guidance for protocols of clinical trials dephosphorylateduncarboxylated matrix gla protein concentration is predictive of vitamin k status and is correlated with vascular calcification in a cohort of hemodialysis patients arterial stiffness: basic concepts and measurement techniques expert consensus document on the measurement of aortic stiffness in daily practice using carotid-femoral pulse wave velocity estimation of central aortic pressure waveform by mathematical transformation of radial tonometry pressure: validation of generalized transfer function prospective evaluation of a method for estimating ascending aortic pressure from the radial artery pressure waveform aortic input impedance in normal man: relationship to pressure wave forms assessment of vascular calcification in esrd patients using spiral ct quantification of coronary artery calcium using ultrafast computed tomography singapore renal registry annual report united states renal data system kdoqi us commentary on the 2017 kdigo clinical practice guideline update for the diagnosis, evaluation, prevention, and treatment of chronic kidney disease-mineral and bone disorder (ckd-mbd) coronary artery calcification correlates with the presence and severity of valve calcification increased aortic calcification is associated with arterial stiffness progression in multiethnic middle-aged men vitamin k2 supplementation in haemodialysis patients: a randomized dose-finding study the trevasc-hdk research team would like to thank nattopharma asa for providing vitamin k2 for the trial. we are grateful to the national university health system's investigational medicine unit, department of diagnostic imaging and cardiovascular imaging core laboratory for their role in the execution of this trial. all authors have contributed to the development of the protocol and study design as members of the research team. the article was draft by sh, tbc, llh, ltls and tl. the manuscript was revised by ad, ls, pk, occ, ls, yex, tjn, ss, chr, tsy, wwk and tbw. all the authors approved the final version of the manuscript and are accountable for the author's own contributions, accuracy or integrity of the manuscript. key: cord-017656-lqrkwlnb authors: lee, wang jae title: common cold and flu date: 2019-08-07 journal: vitamin c in human health and disease doi: 10.1007/978-94-024-1713-5_5 sha: doc_id: 17656 cord_uid: lqrkwlnb most of the causative agents of the common cold are viruses. the respiratory system consists of an air conduction portion and a respiratory portion. the direct initiating factor of the common cold is low temperature, especially relative coldness. when people feel cold or chilly, vascular constriction around the inlet area of air occurs, resulting in a reduction of mucus secretion containing various antiviral soluble mediators and followed by an explosive increase in the nasal viral flora. a relatively low temperature and dryness are good conditions for viral proliferation and invasion to the body. the first symptom of the common cold is usually a runny nose, followed by a sore throat and/or systemic fever. acute symptoms of the common cold are usually terminated within 3 days, at the longest 5~7 days. the mortality rate of severe acute respiratory syndrome (sars) has reached around 10%. a novel swine-origin influenza a (h1n1) virus caused the occurrence of more than 130,000 patients and dead cases of more than 800 people. h5n1 avian influenza showed an extremely high mortality rate, even though its infectivity is low. a new serotype of ai (h7n9) has appeared in some areas of china. vitamin c can prevent the onset of a cold. vitamin c can even prevent influenza virus from spreading down from the upper respiratory tract to the lower one. in addition, levels of interferon (ifn) in the bronchoalveolar lavage (bal) fluid are markedly low in vitamin c-insufficient mice. inflammatory cells are markedly increased in bal fluid, providing the immunological evidences that daily supplementation of high-dose vitamin c can prevent influenza infection and that, in extreme case, it can save the life. small cartilages and small muscles connecting each cartilage, besides its air conduction function. needless to say, the air passing through the entire air conduction portion is fully conditioned air, e.g., cleaned, moistened, and warmed appropriately, arriving at the respiratory portion. the air conduction portion from the bronchus to the terminal bronchiole is called the bronchial tree, which also has a typical respiratory epithelium on their luminal surface. the typical respiratory epithelium consists of several cell types: (1) tall columnar cells are the most abundant ones and have numerous cilia on their apical surface; (2) mucous goblet cells, looking like a typical wine glass, have many polysaccharide-rich mucin droplets on their surface; and (3) there are some miscellaneous cells. functionally, all cilia of the tall columnar cells are fully covered by spreading out the polysaccharide-rich mucous droplets produced by mucous goblet cells, forming the mucociliary blanket. the sticky mucin component laid on the cilia adsorb chemical substances, tiny particles, and even microorganisms, which are removed effectively by one-way movement (from inside to outside) of the mucociliary blanket. therefore, a substantial amount of mucous fluid drains from the bronchial tree into esophagus, a pathway to the gi tract that is the crossroads in the laryngopharyngeal area between the respiratory and gi tracts, every day in humans. the respiratory portion starts from the last and smallest bronchiole, called respiratory bronchioles, which have alveoli intermittently on their way to the terminal portion of respiratory pathway, the alveolar sacs, which are composed of numerous alveoli. wide networks of capillaries cover the external surface of each alveolus, forming the blood air barrier, consisting of the alveolar epithelium and endothelium of its covering capillary, and the fused basal laminae present between them ( fig. 5 .2). o 2 (blue arrows) in the air inhaled into alveoli gets through the blood-air barrier into the capillary, while co 2 (red arrows) transported from cells to the alveolar capillary is penetrated to the alveolar space through the blood air barrier, which consists of alveolar epithelium, fused basal lamina, and capillary endothelium structures of the respiratory system conclusively, o 2 in the alveoli moves into blood capillaries through the blood air barrier, while co 2 in the blood capillaries is transported to the air spaces in the alveoli through the blood air barrier, eventually evacuated to the outside of the body. there is no doubt in the fact that the direct initiating factor of the common cold is low temperatures, i.e., coldness, especially relative coldness, which means a sense of feeling cold due to an unexpected sudden change in the temperature from high to low. here, coldness does not mean an absolute extremely low temperature routinely experienced in both arctic areas year-round. therefore, although the outdoor temperature can be higher than 30 °c, people attending a meeting in a room where the air-cooling system is operating well with the indoor temperature kept around 24-25 °c cannot help but feel cold for a relatively long time, and they can catch the common cold. generally speaking, traditionally, the incidence rate of the common cold during the hot summer has been very low. in the korean proverb, "even the dogs do not catch colds in may and june of the lunar calendar." understanding that may and june in the lunar calendar indicate a midsummer time, it means that korean people rarely catch cold in the midsummer time. however, nowadays, the rate has become relatively high such that it is very common to see cold patients during the summer time because air-cooling systems are found everywhere. it is no wonder to see that the incidence rate of the common cold is not particularly high in the arctic areas where absolute coldness persists year-round, as well as during the cold winter time, when severe cold temperatures persist, because they do not usually feel cold due to routinely being exposed to severe coldness as wells as having low viral colonization due to severe low temperatures. actually, relative coldness means the temperature at which people feel cold in real life. when people feel cold or chilly, a couple of responses take place in their body to keep the core body temperature constant (37.5 °c). first, vascular constriction around the inlet area of air occurs, typically the mucous membrane of the nasal cavity, resulting in a reduction of mucus secretion containing various antiviral soluble mediators, such as interleukins, tnf-α, ifn-γ, and so on, and followed by an explosive increase in the nasal viral flora such as adenovirus and rhinovirus by their rapid proliferation. the nasal viral flora proliferates easily in the relatively cold weather, which causes the relative humidity to become low. a relatively low temperature and dryness are good conditions for viral proliferation and invasion to the body. dryness usually causes injuries in the nasal mucosa, which supplies the route for the initial viral invasion. when the human physical defense system weakens or is broken and viral proliferation increases, the balance between the human body defense system and the viral flora tends to shift to the viral flora, resulting in catching the common cold. that is the reason why there are common cold or flu outbreaks in the late fall season and the transitional season from the hot summer to the cold winter. when the common cold starts just after a prolonged exposure to relative coldness, the first symptom of the common cold is usually a runny nose, which functions to wash out the increased viral flora so that the number of virus infected cells decreases. moreover, people in good physical condition ordinarily do not catch the cold, while people who are not healthy ordinarily due to prolonged fatigue, overwork, or insomnia usually catch the cold. once people catch the cold, the next symptoms after a runny nose are a sore throat and systemic fever. a sore throat means that tissue invasion by the proliferated viral flora has started, followed by inflammation which usually consists of four classical signs of redness, swelling, pain, and heat. systemic fever is a very important innate defense. the higher the body temperature is to some extent, the lower the proliferation rate of the virus is. therefore, normal body temperature itself (37.5 °c) is a very important body defense against bacterial or viral infection. actually, bacterial or viral proliferation is strongly inhibited by high temperatures (higher than 37.5 °c). because it takes a little time (minimally 2-3 days) to activate the adaptive, specific immunity for invading bacteria or a virus, the body defense system uses the high fever as a non-specific defense tool immediately upon viral infection, which works in a very short time. that is the reason why early use of antipyretic agents should not be done for a high fever occurring in the common cold or flu. however, a high fever should be cautiously controlled by pediatricians in the case of youngaged people in whom brain damage is likely to be caused by febrile convulsions. acute symptoms of the common cold are usually terminated within 3 days, at the longest 5-7 days, before the specific adaptive immune system is fully active, unless a secondary bacterial infection is also present. there are a couple of reasons why actually vaccines for the common cold are not available. one is that the common cold comes from an imbalance between the human defense system and the normal viral flora, which normally reside at the initiation part of the respiratory system such as the nasal cavity and nasal or oral pharynx so that they usually do not induce new immunity against the normal floral virus. the second reason is because there are more than 200 viruses that cause the common cold. the third reason is because the common cold has been called a self-limited disease in which it takes just a few days to be cured so that mainly the innate immunity must work but the adaptive immunity does not need to be activated for the eventual termination of the common cold. one more thing is to be considered seriously; the common cold and flu are totally different. the flu is never a severe cold. clinically, it is not easy to tell the flu from a common cold, although there have been some differences in clinical symptoms. briefly, the main symptoms of the common cold are runny nose, mild fever, cough, and sometimes sore throat, while those of the flu are high fever, myalgia (muscle pain), headache, sore throat, and generalized weakness (lethargy) ( table. 5.1). unlike the common cold, which is usually not infected by a foreign pathogen but is just a kind of battle between the body defense system and the normal flora of viruses residing in the upper respiratory system, the flu is a disease caused by an influenza virus infection. thus, the common cold takes place at any time year-round whenever people feel coldness for a relatively long time, while flue outbreaks occur only during some restricted periods (in korea from october to april of the next year) when the influenza virus is prevalent. in march 2003, the who reported officially that a new unidentified fatal disease has appeared in hong kong. it was discovered that the disease is a kind of variant of the common cold caused by a variant coronavirus, which supposedly originated from musk cats raised by some farmers in guangdong, china, in november 2002. the coronavirus is a single-stranded rna virus and has a species specificity as the causative viral agent of infection. however, a genetically modified coronavirus of the musk cat has a new capability to infect beyond the interspecies barrier. it was not just the matter of crossing the interspecies barrier. even though its genetic structure has changed, it is just one of the new causative agents of the common cold, which causes people to become infected with the common cold. unfortunately, some of the patients infected by this variant coronavirus have died. the autopsy of the dead cases revealed that the specific cause of death was viral pneumonia, which rarely occurs in routine common cold patients. since then, the common cold caused by the variant coronavirus is called severe acute respiratory syndrome (sars). epidemiological data show that the mortality rate of sars has reached around 10% (about 780 people dead out of about 83,000 patients), which is high enough to cause people to panic, considering that the mortality rate of the original common cold is near zero. at the end of march 2009, a new strain of type a influenza virus was reported for the first time from a 10-year-old child admitted to one clinic located in san diego, usa, with the chief complaints of high fever, cough, and vomiting. it turned out to be a novel swine-origin influenza a (h1n1) virus that caused the infection. thereafter, this novel flu has spread out to the whole world, resulting in the occurrence of more than 130,000 patients and dead cases of more than 800 people. fortunately, this novel flu could be controlled successfully by the administration of tamiflu, which does not have any treatment effects on the seasonal flu despite having the same serotype (h1n1). therefore, many researchers think that the actual mortality rate of this novel swine-origin influenza a might be more than 10%. influenza virus has two kinds of antigens, which consist of hemagglutinin (h) and neuraminidase (n). hemagglutinin has 15 subtypes (h1~h15), while neuraminidase has 9 subtypes (n1~n9). a combination of h subtypes and n subtypes makes theoretically 135 sub-serotypes of influenza a virus such as h1n1, h3n2, h5n1, h7n9, and h15n9. according to scientific reports, humans are usually infected by unfortunately, this principle has been broken, welcoming a new millennium, in 2000. in late 2003, shocking news was reported that some people living in east asia had been infected by a highly pathogenic avian influenza (ai), for which their serotype was h5n1, which had never been reported before in human medical history at that time. even worse, this h5n1 avian influenza showed an extremely high mortality rate (about 70%), even though its infectivity is low. however, there is good fortune in this misfortune because infection cases between humans have not been identified yet. recently (spring 2013), a new serotype of ai has appeared in some areas of china, for which the serotype is h7n9. according to some reports presented at the meeting of "options for the control of influenza" held in cape town from september 5 to 9, 2013, this new ai is expected to have a higher infectivity and toxicity than h5n1 ai, and in the fall of 2013, a pandemic of this new ai was forecast by the centers for disease control and prevention (cdc) of the usa. in korea, for the last 20 years, the number of people taking a couple of grams of vitamin c daily has increased steadily such that in 2017, it was presumed that about 15 million people were taking a megadose of vitamin c daily. the most frequent cases, which i have observed by telephone or e-mail interviews, have been many people taking a megadose of vitamin c for more than 4-5 years, and for a couple of years, they have never caught a cold, which they used to suffer from one to two times a year when they did not take a megadose of vitamin c. twelve years ago, i was asked to meet a ceo who was in his mid-50s and suffered from multiple episodes of a cold yearly for more than 30 years. he was admitted regularly to a hospital for 1 month due to pulmonary complications from the cold. immediately after meeting with me, he started to take a megadose of vitamin c daily. since then, he has never caught a cold for more than 10 years. this longitudinal study has very meaningful value in estimating the effects of vitamin c on the common cold, even though it is only a single case. clinical studies on the effects of vitamin c on colds presented by some clinicians have shown generally negative results. regular vitamin c consumption may decrease the duration of cold symptoms but does not affect the symptom severity or act as a prophylaxis (heimer et al. 2009 ). the failure of vitamin c supplementation to reduce the incidence of colds in a normal population indicates that preventing a cold by taking routine megadoses of vitamin c is not rationally justified for community use. however, evidence suggests that it could be justified in people exposed to brief periods of severe physical exercise or cold environments (douglas et al. 2007 ). their conclusion is that vitamin c does not have a curative or preventive vitamin c against the common cold effect on colds but shortens the duration of the illness. the common cold is a selflimited viral disease. for a curative treatment, the optimal dose of vitamin c and the right method of administration should be considered. according to a pharmacokinetic study of vitamin c after oral administration, it is most desirable to take vitamin c every 6 h because vitamin c has a 6-h cycle of metabolism as mentioned in chap. 1, the introduction. actually, when it is orally administered, it reaches peak concentration in the peripheral blood 3 h after the administration, and it comes back to the basal level of concentration 6 h after the administration. however, almost all clinical experiments on the effects of vitamin c published so far have been performed on a single dose of vitamin c. furthermore, the daily vitamin c dose used in the above published papers was less than 1000 mg. in addition, it is actually impossible to perform clinical experiments that can confirm if vitamin c can cure or prevent a cold because a cold has a short period as a self-limited disease. once cold patients visit the clinic for treatment, the number of viruses is too high to be controlled by any potent medication such that the balance between the host and the virus is shifted to the virus and the patient usually becomes severely ill. during such an active phase of the cold, no drug can stop the disease process of a cold from occurring in the upper respiratory tract. vitamin c can prevent the onset of a cold if people follow a strict regimen taking a megadose of vitamin c three times daily because it can inhibit the initial phase of viral proliferation, when the number of viruses is not so high and still controllable by the host defense system (furuya et al. 2008) . that is the case with tamiflu, which has been used for successful prevention of the swine flu (h1n1). the correct method of administering tamiflu is to take it within 48 h after the occurrence of fever. if it is taken 48 h or later after a fever occurs, it has no effect on the treatment of swine flu. considering the operating mechanism of tamiflu, which binds to the hemagglutinin protein of the influenza virus and inhibits viral attachment to the host cell resulting in failure of viral replication using the replication machinery of the host cell, tamiflu does not cure the cold but prevents it because tamiflu blocks the initial proliferation of the influenza virus. there have been some reports on the effects of vitamin c on the flu (li et al. 2006; sladkova and kostolansky 2006; banerjee and kaul 2010) . to observe the effects of vitamin c on flu, an in vivo experiment using gulo(−/−) mice, which are unable to synthesize vitamin c like humans because the gene encoding l-gulono-γ-lactone oxidase is knocked out artificially, has been performed by my research team. the experimental animals were divided into three groups with six mice in each group: group 1, wild-type, normal mice; group 2, gulo(−/−) mice without supplementation of vitamin c; and group 3, gulo(−/−) mice with supplementation of oral vitamin c. the mice in each group were infected with h3n2 influenza virus, and then, the survival rate was checked. all the mice in the three groups showed symptoms of the flu such as fever, rhinorrhea, lethargy, and so on. interestingly, 5 days after infection, 80% of the mice in group 2 were dead, while no mice in groups 1 and 3 died (fig. 5.3) . the autopsies showed that the lung tissues from the dead mice were loaded with so much influenza virus, indicating that the mice in group 2 died of viral pneumonia. however, the lung tissues from the mice in groups 1 and 3, which did not die from the infection, did not have the influenza virus (fig. 5.4) (kim et al. 2013) . (kim et al. 2013) these results strongly suggest that vitamin c in a living body might prevent influenza virus from spreading down from the upper respiratory tract to the lower respiratory system such as the bronchi, bronchioles, and alveoli, even though the mechanism involved in the preventing process has not been elucidated yet. however, vitamin c deficiency causes inhibition of camp-dependent secretion of chloride in the mouse airway epithelium so that the epithelium does not maintain fluidity on their surface (our unpublished data) (fig. 5.5) . the dryness of the mucosal epithelium facilitates viral proliferation and invasion. furthermore, vitamin c deficiency dramatically decreases svct expression on the mucosal epithelium of respiratory tracts, leading to an abolition of the prevention effects of vitamin c from flu infection (our unpublished data) (fig. 5.6 ). in addition, levels of interferons (ifns) in the bronchoalveolar lavage (bal) fluid (fig. 5.7) , which have very critical roles in the defense of viral infection, are markedly low in vitamin c insufficiency group. however, levels of representative pro-inflammatory cytokines, such as tnf-α and il-1α and il-1β in bal fluid, are transepithelial voltage (vte) and short-circuit current (isc) analysis. vitamin c deficiency causes inhibition of camp-dependent secretion of chloride in the mouse airway epithelium so that the epithelium does not maintain fluidity on their surface, resulting in facilitation of viral invasion and proliferation significantly high in vitamin c insufficiency group. inflammatory cells are also markedly increased in bal fluid ( fig. 5.8 ) (kim et al. 2013) . these all in vivo data provide the immunological evidences that daily supplementation of high-dose vitamin c can prevent influenza infection and that, in extreme case, it can save the life. (2). vitamin c deficiency increases production of several pro-inflammatory cytokines such as il-1α (a), il-1β (b), and tnf-α (c), especially during h3n2 influenza infection, and it also causes increase of the inflammatory cells in bal fluid (d). wt, normal mice group; gulo(−/−), mice group which cannot produce vitamin c like humans; gulo(−/−) + vc, gulo(−/−) mice group fed with daily vitamin c in the drinking water combined inhalational and oral supplementation of ascorbic acid may prevent influenza pandemic emergency: a hypothesis vitamin c for preventing and treating the common cold antiviral effects of ascorbic and dehydroascorbic acids in vitro examining the evidence for the use of vitamin c in the prophylaxis and treatment of the common cold vitamin c is an essential factor on the anti-viral immune responses through the production of interferon--α/β at the initial stage of influenza a virus (h3n2) infection vitamin c deficiency increases the lung pathology of influenza viruainfected gulo(−/−) mice the role of cytokines in the immune response to influenza a virus infection key: cord-317758-oym8s4af authors: manson, joann e.; bassuk, shari s. title: commentary. eliminating vitamin d deficiency during the covid-19 pandemic: a call to action date: 2020-07-23 journal: metabolism doi: 10.1016/j.metabol.2020.154322 sha: doc_id: 317758 cord_uid: oym8s4af nan j o u r n a l p r e -p r o o f long known as critical for bone health, and increasingly recognized as important for cardiometabolic and other non-skeletal outcomes, vitamin d has most recently attracted interest for its possible protective role against covid-19. if vitamin d is beneficial in this regard-and accumulating evidence suggests that it may be-then the high prevalence of vitamin d deficiency in the united states and globally, especially among nonwhite racial/ethnic groups, is cause for heightened concern and should be rectified expeditiously. this commentary serves as an urgent call to action, with the aim of improving public health during-and after-the covid-19 pandemic. current clinical vitamin d guidelines, which focus on maintenance of bone health, classify serum 25-hydroxyvitamin d (25(oh)d) levels of 20-50, 12-20, and less than 12 ng/ml as indicative of vitamin d sufficiency, inadequacy, and deficiency, respectively (to convert from ng/ml to nmol/l, multiply by 2.5). 1 by these criteria, nearly one quarter (23.3%) of the overall u.s. population has 25(oh)d levels in the insufficient or deficient range. 2 race/ethnicity differentials are striking; in the u.s., more than one half (53.3%) of blacks, more than one third (36.7%) of asians, and nearly one third (32.2%) of hispanics have 25(oh)d levels that place them at risk of vitamin d insufficiency or deficiency, compared with about 1 in 7 (13.9%) non-hispanic whites. for vitamin d deficiency alone, the corresponding percentages are 17.5%, 7.6%, 5.9%, and 2.1%, respectively. multiple lines of evidence suggest that vitamin d status may be relevant to covid-19 incidence and severity (table) . laboratory (cell-culture) investigations have documented vitamin d action in pathways relevant to immune function, as well as the expression of the vitamin d receptor in innate and adaptive immune system cells. 3 vitamin d may reduce infection risk by lowering viral replication rates through the induction of antimicrobial peptides, including cathelicidin. vitamin d also has immunomodulatory properties and can lower inflammation, which may help to avert the j o u r n a l p r e -p r o o f inflammatory response thought to be at least partly responsible for the respiratory complications seen in some covid-19 patients. 4 moreover, vitamin d is a key modulator of the reninangiotensin system and may counteract the reduction in angiotensin-converting enzyme 2 (ace2) activity, rise in angiotensin-converting enzyme (ace) activity, increased production of angiotensin ii, and pulmonary vasoconstriction that occur when inhaled severe acute respiratory syndrome coronavirus 2 (sars-cov-2) binds to ace2 receptors on alveolar epithelial cells. 5 ecologic studies show lower covid-19 mortality in countries or regions with greater solar ultraviolet-b radiation (associated with increased cutaneous synthesis of vitamin d) or populations with higher mean 25(oh)d levels. 4 moreover, within a given country or region, demographic groups known to be at elevated risk for vitamin d insufficiency-not only black individuals, but also the elderly, nursing-home residents, and those with obesity, vascular comorbidities, or chronic kidney disease-are also those at higher risk of covid-19 hospitalization and/or mortality. observational studies also suggest a beneficial role of vitamin d. studies of individuals tested for sars-cov-2 show that 25(oh)d levels measured concurrently with or up to 1 year prior to viral testing are inversely associated with the likelihood of a positive test result. 6 in addition, a growing number of studies of patients with confirmed sars-cov-2 infection find that 25(oh)d levels correlate inversely with illness severity. 6 for example, among 212 covid-19 patients at three south asian hospitals, the risk of severe as opposed to mild illness was approximately eight times higher in those who were vitamin d deficient than in those who were vitamin d sufficient. 7 among 780 covid-19 patients in indonesia, 25(oh)d levels below 20 ng/ml, as compared with levels of 30 ng/ml or greater, were predictive of a 10-fold increase in mortality risk after controlling for age, sex, and comorbidity status. 8 considered as a whole, the accumulating evidence is becoming increasingly compelling. that said, it is not yet definitive. ecologic and observational data are susceptible to confounding, reverse causation bias, and other threats to validity that preclude their use for establishing causality, and randomized trial data regarding other viral diseases may not generalize to covid-19. well-designed trials that overcome these limitations are needed to evaluate the efficacy of vitamin d supplementation for covid-19 prevention and/or treatment. several such trials are underway, including our own. their eventual results should allow a definitive determination of whether, and at what dose, vitamin d reduces risk of developing covid-19, improves clinical outcomes, and strengthens response to future vaccination. in the meantime, it is more important than ever to embrace commonsense measures that will, on a population-wide basis, reduce the risk for vitamin d insufficiency and deficiency. with summer upon us, clinicians and public health authorities should encourage patients and the general public to spend time outdoors and be physically active, while adhering to evolving social distancing guidelines. the skin can synthesize enough vitamin d to avert deficiency with as little as 15 minutes per day of sun exposure, although this time varies according to latitude, season, time of day, cloud cover, clothing coverage, sunscreen use, and skin pigmentation (those with darker skin will need more time in the sun than those with lighter skin), and extended exposure increases skin cancer risk. therefore, the message that diet is j o u r n a l p r e -p r o o f also important to achieve a healthy vitamin d level should be conveyed. good dietary sources include fortified foods such as milk, yogurt, orange juice, and cereals; oily fish such as salmon, rainbow trout, canned tuna, and sardines; eggs; and sun-dried mushrooms. a helpful table listing the vitamin d content of these and other foods is available. 11 patients and the general public should also be advised to read nutrition labels, which are required to list the vitamin d content. in this period of heightened "vitamin d awareness," clinicians and public health authorities in countries that lack food fortification policies should advocate for a timely implementation of such policies to reduce vitamin d deficiency. for people who are unable to be outdoors and also have low dietary vitamin d intake, supplementation is prudent. the recommended dietary allowance of vitamin d from food plus supplements is 600 iu/day for adults up to age 70 years and 800 iu/day for those above age 70, 1 but during the current pandemic, a supplement containing 1000-2000 iu/day of vitamin d would be reasonable. however, routine use of doses above the safety limit of 4000 iu/day should be avoided to minimize risk of hypercalcemia and other adverse events. vitamin d is essential for health. although additional research on its contribution to attenuating covid-19 risk and severity is in progress, eliminating vitamin d deficiency will improve public health during the current pandemic and after the threat subsides. dietary reference intakes for calcium and vitamin d. washington dc: the national academies press vitamin d status in the united states vitamin d and the immune system vitamin d and inflammation: potential implications for severity of covid-19 letter: does vitamin d have a potential role against covid-19? rapid response: low vitamin d: high risk covid-19 mortality? seven preprints suggest that is case vitamin d supplementation could possibly improve clinical outcomes of patients infected with coronavirus-2019 (covid-19) patterns of covid-19 mortality and vitamin d: an indonesian study key: cord-329997-jhejhz6d authors: muscogiuri, giovanna; barrea, luigi; savastano, silvia; colao, annamaria title: nutritional recommendations for covid-19 quarantine date: 2020-04-14 journal: eur j clin nutr doi: 10.1038/s41430-020-0635-2 sha: doc_id: 329997 cord_uid: jhejhz6d nan the world is currently experiencing the pandemic of coronavirus (cov). in late 2019, the cov infection began in wuhan, hubei, china. it had been originally called 2019 ncov and it has been renamed covid-19 by the world health organization on february 2020. this epidemic began with animal-to-human infection, and the direct cause of death is generally due to ensuing severe atypical pneumonia. covid-19 has now been declared a pandemic by the world health organization, and people in all countries are under quarantine in order to reduce the spread of the virus, which then also lessens the impact on medical resources. since quarantine is associated to the interruption of the work routine, this could be result in boredom. boredom has been associated with a greater energy intake, as well as the consumption of higher quantities of fats, carbohydrates, and proteins [1] . further, during quarantine continuously hearing or reading about the pandemic without a break can be stressful. consequently, the stress pushes people toward overeating, mostly looking for sugary "comfort foods" [2] . this desire to consume a specific kind of food is defined as "food craving", which is a multidimensional concept including emotional (intense desire to eat), behavioral (seeking food), cognitive (thoughts about food), and physiological (salivation) processes [3] . of interest, a gender difference has been reported in food craving, with a higher prevalence in women than in men. carbohydrate craving encourages serotonin production that in turn has a positive effect on mood. in a sense, carbohydrate-rich foods can be a way of self-medicating anti stress. the effect of carbohydrate craving on low mood is proportional to the glycemic index of foods. this unhealthy nutritional habit could increase the risk of developing obesity that beyond being a chronic state of inflammation, it is often complicated by heart disease, diabetes, and lung disease that have been demonstrated to increase the risk for more serious complications of covid-19 [4] . quarantinerelated stress also results in sleep disturbances that in turn further worsen the stress and increase food intake thus giving rise to a dangerous vicious cycle. therefore, it is important to consume food containing or promoting the synthesis of serotonin and melatonin at dinner. a considerable variety of plant species including roots, leaves, fruits, and seeds such as almonds, bananas, cherries, and oats contain melatonin and/or serotonin. these foods may also contain tryptophan, which is a precursor of serotonin and melatonin. protein foods such as milk and milk products are the main sources of the sleep-inducing amino acid tryptophan. moreover, tryptophan is involved in the regulation of satiety and caloric intake via serotonin that mainly lowers carbohydrate and fat intake, and inhibits neuropeptide y, the most powerful hypothalamic orexigen peptides [5] . further, beyond sleep-inducing properties, milk products such as yogurt could also augmented natural killer cell activity and reduce the risk of respiratory infections [6] during quarantine the increased intake of macronutrients could also be accompanied by micronutrients deficiency as occurs in obesity [7] , which is commonly associated with impaired immune responses, particularly cell-mediated immunity, phagocyte function, cytokine production, secretory antibody response, antibody affinity, and the complement system, thus making more susceptible to viral infections [8] . thus, during this time it is important to take care of nutritional habits, following a healthy and balanced nutritional pattern containing a high amount of minerals, antioxidants, and vitamins. several studies reported that fruits and vegetables supplying micronutrients can boost immune function. this happens because some of these micronutrients such as vitamin e, vitamin c, and betacarotene are antioxidants. anti-oxidants increase the number of t-cell subsets, enhance lymphocyte response to mitogen, increased interleukin-2 production, potentiated natural killer cell activity, and increased response to influenza virus vaccine compared with placebo [9] . beta carotene is most abundant in sweet potatoes, carrots, and green leafy vegetables while sources of vitamins c include red peppers, oranges, strawberries, broccoli, mangoes, lemons, and other fruits and vegetables. the major dietary sources of vitamin e are vegetable oils (soybean, sunflower, corn, wheat germ, and walnut), nuts, seeds, spinach, and broccoli. in addition, quarantine could be associated to a less time spent outdoor, less sun-exposure, and reduced production of vitamin d as a result of lower levels of 7-dehydrocholesterol in the skin. vitamin d deficiency in winter has been reported to be associated to viral epidemics. indeed, adequate vitamin d status reduces the risk of developing several chronic diseases such as cancers, cardiovascular disease, diabetes mellitus, and hypertension that significantly higher risk of death from respiratory tract infections than otherwise healthy individuals [10] . further, vitamin d protects respiratory tract preserving tight junctions, killing enveloped viruses through induction of cathelicidin and defensins, and decreasing production of proinflammatory cytokines by the innate immune system, therefore reducing the risk of a cytokine storm leading to pneumonia. since the time spent outdoor and consequently the sun exposure is limited, it is encouraged to get more vitamin d from diet. foods containing vitamin d include fish, liver, egg yolk and foods (e.g., milk, yogurt) with added vitamin d. another essential trace element that is crucial for the maintenance of immune function is zinc. it has been reported that zinc inhibited severe acute respiratory syndrome (sars) coronavirus rna-dependent rna polymerase (rdrp) template binding and elongation in vero-e6 cells [11] . although oysters contain the most zinc per serving, the most common food to get zinc are represented from poultry, red meat, nuts, pumpkin seeds, sesame seeds, beans, and lentils. all the above described nutrients are enclosed in mediterranean diet pattern that could represent a healthy nutritional pattern to be followed in quarantine. key ingredients of mediterranean cuisine include olive oil, fresh fruits and vegetables, protein-rich legumes, fish, and whole grains with moderate amounts of wine and red meat. in conclusion, due to the quarantine-related situational stress-eating, nutrition becomes a priority at this time. many people probably have much of what they might need at home, and so there is no reason to rush to buy groceries creating mass gatherings that could contribute to the spread of covid 19 because during quarantine food stores stay open throughout. keeping foods that are good sources of immuno-supportive nutrients, planning times to eat, meals, portions and having a cutoff time for eating but mostly having in mind positive attitudes could be helpful to tackle the negative health effects of quarantine. conflict of interest the authors declare that they have no conflict of interest. publisher's note springer nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. eaten up by boredom: consuming food to escape awareness of the bored self neuroactive compounds in foods: occurrence, mechanism and potential health effects food craving: new contributions on its assessment, moderators, and consequences risk factors associated with acute respiratory distress syndrome and death in patients with coronavirus disease 2019 pneumonia in wuhan, china diet promotes sleep duration and quality reducing the risk of infection in the elderly by dietary intake of yoghurt fermented with lactobacillus delbrueckii ssp. bulgaricus oll1073r-1 impact of micronutrient deficiencies on obesity micronutrients and immune function: some recent developments effect of vitamin and trace-element supplementation on immune responses and infection in elderly subjects vitamin d and chronic diseases: the current state of the art zn(2+) inhibits coronavirus and arterivirus rna polymerase activity in vitro and zinc ionophores block the replication of these viruses in cell culture key: cord-286960-uz34fjyp authors: ali, nurshad title: role of vitamin d in preventing of covid-19 infection, progression and severity date: 2020-06-20 journal: j infect public health doi: 10.1016/j.jiph.2020.06.021 sha: doc_id: 286960 cord_uid: uz34fjyp the outbreak of covid-19 has created a global public health crisis. little is known about the protective factors of this infection. therefore, preventive health measures that can reduce the risk of infection, progression and severity are desperately needed. this review discussed the possible roles of vitamin d in reducing the risk of covid-19 and other acute respiratory tract infections and severity. moreover, this study determined the correlation of vitamin d levels with covid-19 cases and deaths in 20 european countries as of 20 may 2020. a significant negative correlation (p = 0.033) has been observed between mean vitamin d levels and covid-19 cases per one million population in european countries. however, the correlation of vitamin d with covid-19 deaths of these countries was not significant. some retrospective studies demonstrated a correlation between vitamin d status and covid-19 severity and mortality, while other studies did not find the correlation when confounding variables are adjusted. several studies demonstrated the role of vitamin d in reducing the risk of acute viral respiratory tract infections and pneumonia. these include direct inhibition with viral replication or with anti-inflammatory or immunomodulatory ways. in the meta-analysis, vitamin d supplementation has been shown as safe and effective against acute respiratory tract infections. thus, people who are at higher risk of vitamin d deficiency during this global pandemic should consider taking vitamin d supplements to maintain the circulating 25(oh)d in the optimal levels 75-125 nmol/l. in conclusion, there not enough evidence on the association between vitamin d levels and covid-19 severity and mortality. therefore, randomized control trials and cohort studies are necessary to test this hypothesis. vitamin d is a steroid hormone, produced endogenously with the effect of ultraviolet radiation on the skin or available from exogenous food sources or dietary supplements. vitamin d insufficiency is a public health problem affecting over a billion people across all life stages worldwide [1] . in the past decade, several studies demonstrated a potential link between vitamin d deficiency and various diseases, including systemic infection [2] [3] [4] . vitamin d insufficiency affects the immune functions as vitamin d exerts an immunomodulation role [5] , increasing innate immunity by secretion of antiviral peptides [6, 7] , which improves mucosal defenses. in clinical studies, low levels of serum vitamin d were associated with acute respiratory tract infections including epidemic influenza [8] [9] [10] . a recent meta-analysis incorporating data from j o u r n a l p r e -p r o o f 3 eight observational studies reported that subjects with a serum vitamin d concentration <50nmol/l (i.e. <20ng/ml) had a 64% increased risk of community-acquired pneumonia [11] . some recent reviews hypothesized that vitamin d insufficiency may compromise respiratory immune function, increasing the risk of covid-19 severity and mortality [12, 13] . there are also some retrospective studies that determined the correlation of vitamin d levels with covid-19 severity and mortality [14] [15] [16] [17] [18] [19] [20] [21] [22] the recent outbreak and fast spreading of sars-cov-2 are a global health threat with an unstable outcome worldwide. a recent data reported the antiviral effects of vitamin d, which can hinder viral replication directly, and also be effective in an anti-inflammatory and immunomodulatory way [23] . it seems that sars-cov-2 primarily uses the immune evasion process during infection, which is followed by hyper reaction and cytokine storm in some patients [24] , as a known pathogenic process of acute respiratory disease syndrome (ards) development [25] . sars-cov-2 uses angiotensin-converting enzyme 2 as the host receptor to enter into alveolar and intestinal epithelial cells [26] . subsequent dysregulation of the reninangiotensin system may lead to excess cytokine production resulting in prospective fatal ards [25] . considering the differences in the severity and fatality of covid-19 in the globe, it is important to understand the reasons behind it. improvement of immunity through better nutrition might be a considerable factor. the nutrient such as vitamin d shows significant roles in immune function. some recent reviews demonstrated some pathways by which vitamin d decreases the risk of microbial infections [28] [29] [30] [31] . vitamin d follows different mechanisms in reducing the risk of viral infection and mortality. to reduce the risk of common cold, vitamin d uses three pathways: physical barrier, cellular natural immunity, and adaptive immunity [32] . a recent review also supported the possible role of vitamin d in decreasing the risk of covid-19 infections and mortality [12] . these comprise maintaining of cell junctions, and gap junctions, increasing cellular immunity by decreasing the cytokine storm with influence on interferon γ and tumor necrosis factor α [12] and regulating adaptive immunity through inhibiting t helper cell type 1 responses and stimulating of t cells induction [33] . vitamin d supplementation was also found to enhance cd4+ t cell count in hiv infection [34] . one of the major manifestations of severe sars-cov-2 infection was lymphopenia [35] . in both the mouse models and in human cell lines, vitamin d exerted activity in lung tissue and played protective effects on experimental interstitial pneumonitis [36] . several in vitro studies j o u r n a l p r e -p r o o f 5 demonstrated that vitamin d plays a significant role in local "respiratory homeostasis" either by stimulating the exhibition of antimicrobial peptides or by directly interfering with the replication of respiratory viruses [37] . vitamin d insufficiency can, therefore, be involved in ards and heart failure [12] and these are the manifestations of severely ill covid-19 subjects. therefore, vitamin d deficiency promotes the renin-angiotensin system (ras), which may lead to chronic cardiovascular disease (cvd) and reduced lung function [38] . people with such comorbidities account for a higher percentage of severe ill cases in covid-19 [35] . although, many studies supported the immunomodulatory characteristics of vitamin d and its significant role in the maintenance of immune homeostasis; well-designed randomized controlled trials are required to elucidate the plausible role of vitamin d in protective immune responses against respiratory microbes and in preventing various types of acute respiratory tract infections. yet, it is important to fully elucidate the virulence mechanisms of covid-19, several cellular mechanisms including papain-like protease (plpro)-mediated replication, dipeptidyl peptidase-4 receptor (dpp-4/cd26) binding, disruption of m-protein mediated type-1 ifn induction and mda5 and rig-i host-recognition evasion have been recognized in the closely-related covid-mers virus [39, 40] . of the above process, human dpp-4/cd26 has been exhibited to connect with the s1 domain of the covid-19 spike glycoprotein, suggesting that it could also be a salient virulence factor in covid-19 infection [41] . the expression of the dpp-4/cd26 receptor is reduced significantly in vivo upon the correctness of vitamin d insufficiency [42] . there is also an indication that maintaining of vitamin d may reduce some of the unfavorable downstream immunological sequelae thought to extract poorer clinical outcome in covid-19 j o u r n a l p r e -p r o o f 6 infection, such as interleukin 6 elevation, delayed interferon-gamma response [37] , and, a negative prognostic marker in subjects with acutely-ill pneumonia [43] , including those having covid-19. some clinical and epidemiological studies support to outline the hypothesis regarding covid-19 and its relationship with vitamin d status. recent studies indicated that covid-19 is associated with the increased generation of pro-inflammatory cytokines, c-reactive protein (crp), ards, pneumonia, and heart failure [44] [45] [46] [47] . in china, chronic fatality rates were 6-10% for people with chronic respiratory tract disease, cardiovascular disease, hypertension, and diabetes [12, 48] . in other studies, serum concentrations of 25(oh)d were inversely associated with pro-inflammatory cytokines, il-6, increased crp, and increased risk of pneumonia, ards, diabetes and heart failure [11, [49] [50] [51] [52] [53] [54] . in randomized control trials, vitamin d supplementation has been shown to reduce the risk of respiratory diseases [55, 56] . a placebocontrolled trial with 5660 subjects showed that vitamin d supplementation significantly reduces the risk of respiratory tract infections [57] . a review included five clinical studies reported that respiratory tract infections were significantly lower in the vitamin d supplementation group than the control group [58] . another study included 25 randomized controlled trials, with 10,933 participants in total from 14 different countries indicated the beneficial effects of vitamin d supplementation in reducing the risk of at least one acute respiratory tract infection [59] . (table 1) were obtained for 20 may 2020 (all countries after peak) from the global coronavirus pandemic data portal at https://www.worldometers.info/coronavirus/ [27]. the data for mean serum vitamin d concentrations of these 20 countries were obtained from a previous publication [60] . in pearson's correlation coefficient test, a significant correlation (r = -0.477, p = 0.033) was observed between mean concentrations of vitamin d and number of covid-19 cases/ 1 m population (table 1 and figure 1 ). while, the relationship between mean vitamin d concentrations and the number of covid-19 deaths/ 1m population was not significant (r = -0.357, p = 0.123). in the present analysis, the negative correlation between vitamin d levels and covid-19 cases is stronger than that (r = -0.444, p = 0.050) observed on 8 april 2018 (most countries before the peak) in a previous analysis [19] . however, the negative correlation of vitamin d with covid-19 deaths in the present analysis seems to be more insignificant than the previous analysis ( table 1 ). the number of cases and deaths per million populations varied from country to country at these two time periods. there is a probability that there exists a cause-effect relationship. the underlying differences in the age distribution, population composition, pre-existing medical conditions and variation in medication uses might be potential confounding variables that could affect the correlation. up to now, there is a lack of clinical trials and cohort studies in determining the preventing role in singapore, a small cohort observation study [62] an indonesian retrospective cohort study included 780 cases reported that older and male cases with pre-existing medical conditions and below-normal vitamin d levels are associated with higher odds of death [22] . in that study, after adjustment of confounders (age, sex and comorbidity), vitamin d status showed a strong relationship with covid-19 mortality [22] . a retrospective study in the mainland of usa included a large number of cases demonstrated that j o u r n a l p r e -p r o o f 9 sunlight and vitamin d, with latitude as an indicator, possibly associated with reduced risks for both covid-19 cases and mortality [21] . on the other hand, a study used uk biobank data (2006-2010) for vitamin d status, and ethnicity and correlated with covid-19 cases [18] ; no significant difference was observed for vitamin d levels with covid-19 cases after adjustment of potential confounders. however, ethnicity showed a significant association with covid-19 infection in univariate analysis. another study used the same uk biobank data (2006-2010) for bmi, vitamin d status and ethnicity and noted some interesting observations [15] . the authors did not find any significant difference for mean vitamin d levels between covid-19 cases and the control group. vitamin however, in the regression model, the interaction between bmi and vitamin d status did not predict test results in the available dataset. it is important to note that there are some potential factors that are associated with covid-19 severity and mortality, such as age, sex, ethnicity, comorbidities and co-infection. a study determined the impact of comorbidities on 1590 covid-19 patients in china and reported that covid-19 patients with any comorbidity (hypertension, diabetes) produced poorer clinical outcomes than those without [63] . another study in south korea indicated an association of comorbidities with covid-19 infection and severe clinical courses [64] . a systematic review and meta-analysis demonstrated that age and the underlying disease including hypertension, j o u r n a l p r e -p r o o f cardiovascular disease, and respiratory system disease are possible risk factors for severe covid-19 patients compared to non-severe patients [65] . besides comorbidities, co-infections might be another important determinant of severity and mortality in covid-19 patients. both bacterial and fungal co-infections have been identified in covid-19 patients [66] . currently, there is no clear evidence that people living with hiv are at higher risk of covid-19 infection. however, people living with hiv who have a compromised immune system need extra caution to prevent covid-19 infections. the importance of co-infections in the severity of respiratory diseases has been widely studied; however, they are understudied in the covid-19 outbreak. therefore, more data on co-infections are required to determine their impacts on covid-19 severity and mortality. infections and severities but have not yet reported their findings. up to now, there is a small cohort study described above [16] that demonstrated the protective effects of combined vitamin d, mg and vitamin b12 against clinical deterioration of covid-19. in a previous meta-analysis, vitamin d supplementation has been shown as safe and effective in preventing acute respiratory tract infections [59] . they also added that subjects who had severe vitamin d deficiency experienced the maximum benefits from the supplementation. the authors also noticed that the j o u r n a l p r e -p r o o f 11 protective role of vitamin d was high in subjects with a baseline serum 25(oh)d levels <25 nmol/l compared to those with serum 25(oh)d concentrations >25 nmol/l [59] . in the same study, subgroup analysis indicated that daily or weekly intake of vitamin d (without additional bolus doses) showed protective effects against acute respiratory tract infection, especially in persons with vitamin d deficiency. d supplementation also found to increase gene expression related to antioxidation (glutathione reductase modifier subunit) [67] . the increased production of glutathione spares the use of vitamin c, which has potential antimicrobial activities [68, 69] , and has been suggested to prevent and treat covid-19 infection [12] . up to now, there is limited evidence that supplementation of vitamin d at 20-50 µg/day has any adverse health effects. indeed, supplementation of vitamin d with doses up to 100 µg/day is safe for adults [70, 71] , and many expert groups now suggest supplementation in older people, although at lower levels than it. a study reported that intake of vitamin d supplement at 100 to 250 µg/day over 6 weeks increases the baseline serum concentration of 25(oh)d from 2 to 3 folds, respectively, without any adverse health effects [72] . thus from literature, it is worth to suggest take up to 250 µg/day for a month which is effective to increase the serum levels of 25(oh)d into the optimal range 75-125 nmol/l. the dose can be reduced to 100 µg/day after one month to maintain the circulating concentrations of 25(oh)d [70, 71] . however, future clinical trials may be worth evaluating the potency of different vitamin d dosing plans on acute respiratory tract infections, for example once per week, which can be easier for implementation. the serum response to the given dose is largely varied between the individuals due to differences in demographic and biological variables, such as ethnicity, age, duration of exposure, seasonal variations, body mass index, intake of certain medications, j o u r n a l p r e -p r o o f 12 baseline concentration of vitamin d, genetics and type of vitamin d supplements [73, 74] . moreover, heterogeneity of the population as well as the dose of vitamin d needs to be considered during determining the preventing role of vitamin d in covid-19. to evaluate the impacts of vitamin d supplementation in randomized controlled trials, emphasis should be given on study design based on serum concentration of 25(oh)d rather than administered dose concentration [74] . a recent review also suggested magnesium supplementation with vitamin d supplements as magnesium helps in regulating phosphate and calcium homeostasis [12] . the enzymes involved in vitamin d metabolism seem to need magnesium which plays an important role as a cofactor in enzymatic reactions especially in the kidney and liver [75] . in the randomized trials and meta-analysis, vitamin d supplementation has been shown to have protective effects against respiratory tract infections; therefore, people who are at higher risk of vitamin d deficiency during this global pandemic should consider taking vitamin d supplements to maintain the circulating 25(oh)d in the optimal levels 75-125 nmol/l. some retrospective studies demonstrated a correlation between vitamin d and covid-19 cases and outcomes, while other studies did not find the correlation when confounding variables are adjusted. yet, there is insufficient evidence on the association between vitamin d levels and covid-19 severity and mortality. therefore, randomized controlled trials and large-scale cohort studies are necessary to test this hypothesis. the author has no conflict of interest to declare. the vitamin d deficiency pandemic: approaches for diagnosis, treatment and prevention vitamin d in autoimmunity: molecular mechanisms and 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cases of 2019 novel coronavirus pneumonia in wuhan, china: a descriptive study mechanisms of action of vitamin d as supplemental therapy for pneumocystis pneumonia immunomodulatory and antimicrobial effects of vitamin c the antiviral properties of vitamin c randomized comparison of the effects of the vitamin d3 adequate intake versus 100 mcg (4000 iu) per day on biochemical responses and the wellbeing of patients benefit-risk assessment of vitamin d supplementation the effect of various doses of oral vitamin d3 supplementation on gut microbiota in healthy adults: a randomized, double-blinded, dose-response study factors affecting 25-hydroxyvitamin d concentration in response to vitamin d supplementation editorial-vitamin d status: a key modulator of innate immunity and natural defense from acute viral respiratory infections role of magnesium in vitamin d activation and function na i) in univariate analysis, older and male cases with preexisting medical condition and below normal vitamin d levels were associated with higher odds of death. ii) after adjustment of confounders (age, sex and comorbidity), vitamin d levels showed a strong relationship with covid-19 mortality. key: cord-262773-mfta0emi authors: jolliffe, d.; camargo, c. a.; sluyter, j.; aglipay, m.; aloia, j.; bergman, p.; damsgaard, c.; dubnov-raz, g.; esposito, s.; ganmaa, d.; gilham, c.; ginde, a.; grant, c.; griffiths, c.; hibbs, a. m.; janssens, w.; khadilkar, a. v.; laaksi, i.; lee, m. t.; loeb, m.; maguire, j.; mauger, d. t.; majak, p.; manaseki-holland, s.; murdoch, d.; nakashima, a.; neale, r. e.; rake, c.; rees, j.; rosendahl, j.; scragg, r.; shah, d.; shimizu, y.; simpson-yap, s.; trilok kumar, g.; urashima, m.; martineau, a. r. title: vitamin d supplementation to prevent acute respiratory infections: systematic review and meta-analysis of aggregate data from randomised controlled trials date: 2020-07-17 journal: nan doi: 10.1101/2020.07.14.20152728 sha: doc_id: 262773 cord_uid: mfta0emi objectives: to assess the overall effect of vitamin d supplementation on risk of acute respiratory infection (ari), and to identify factors modifying this effect. design: we conducted a systematic review and meta-analysis of data from randomised controlled trials (rcts) of vitamin d for ari prevention using a random effects model. pre-specified sub-group analyses were done to determine whether effects of vitamin d on risk of ari varied according to baseline 25-hydroxyvitamin d (25[oh]d) concentration or dosing regimen. data sources: medline, embase, the cochrane central register of controlled trials (central), web of science, clinicaltrials.gov and the international standard rct number (isrctn) registry from inception to may 2020. eligibility criteria for selecting studies: double-blind rcts of supplementation with vitamin d or calcidiol, of any duration, were eligible if they were approved by a research ethics committee and if ari incidence was collected prospectively and pre-specified as an efficacy outcome. results: we identified 40 eligible rcts (total 30,956 participants, aged 0 to 95 years). data were obtained for 29,841 (96.5%) of 30,909 participants in 39 studies. for the primary comparison of vitamin d supplementation vs. placebo, the intervention reduced risk of ari overall (odds ratio [or] 0.89, 95% ci 0.81 to 0.98; p for heterogeneity 0.009). no statistically significant effect of vitamin d was seen for any of the sub-groups defined by baseline 25(oh)d concentration. however, protective effects were seen for trials in which vitamin d was given using a daily dosing regimen (or 0.75, 95% ci 0.61 to 0.93); at daily dose equivalents of 400-1000 iu (or 0.70, 95% ci 0.55 to 0.89); and for a duration of [≤]12 months (or 0.82, 95% ci 0.72 to 0.94). vitamin d did not influence the proportion of participants experiencing at least one serious adverse event (or 0.94, 95% ci 0.81 to 1.08). risk of bias within individual studies was assessed as being low for all but two trials. a funnel plot showed asymmetry, suggesting that small trials showing non-protective effects of vitamin d may have been omitted from the meta-analysis. conclusions: vitamin d supplementation was safe and reduced risk of ari, despite evidence of significant heterogeneity across trials. the overall effect size may have been over-estimated due to publication bias. protection was associated with administration of daily doses of 400-1000 iu vitamin d for up to 12 months. the relevance of these findings to covid-19 is not known and requires investigation. conclusions: vitamin d supplementation was safe and reduced risk of ari, despite evidence of significant heterogeneity across trials. the overall effect size may have been over-estimated due to publication bias. protection was associated with administration of daily doses of 400-1000 iu vitamin d for up to 12 months. the relevance of these findings to covid-19 is not known and requires investigation. . cc-by-nc-nd 4.0 international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted july 17, 2020. . https://doi.org/10.1101/2020.07.14.20152728 doi: medrxiv preprint • a previous individual participant data meta-analysis from 10 • sub-group analysis revealed most benefit in those with the lowest vitamin d status at baseline and not receiving bolus doses. • we updated this meta-analysis with trial-level data from an additional 14 placebo-controlled rcts published since december 2015 (i.e. new total of 39 studies with 29,841 participants). • an overall protective effect of vitamin d supplementation against ari was seen (nnt=36). • a funnel plot revealed evidence of publication bias, which could have led to an over-estimate of the protective effect. • no statistically significant effect of vitamin d was seen for any of the sub-groups defined by baseline 25(oh)d concentration. • strongest protective effects were associated with administration of daily doses of 400-1000 iu vitamin d for ≤ 12 months (nnt=8). . cc-by-nc-nd 4.0 international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. (which was not certified by peer review) interest in the potential for vitamin d supplementation to reduce risk of acute respiratory infections (ari) has increased since the emergence of the covid -19 pandemic. 1 this stems from findings of laboratory studies, showing that vitamin d metabolites support innate immune responses to respiratory viruses, 2 together with observational studies reporting independent associations between low circulating levels of 25-hydroxyvitamin d (25[oh]d, the widely accepted biomarker of vitamin d status) and increased risk of ari caused by other pathogens. 3 4 randomised controlled trials (rcts) of vitamin d for the prevention of ari have produced heterogeneous results, with some showing protection, and others reporting null findings. we previously meta-analysed individual participant data from 25 rcts and showed a protective overall effect that was stronger in those with lower baseline 25(oh)d levels, and in trials where vitamin d was administered daily or weekly rather than in more widely spaced bolus doses. 30 since the date of the final literature search performed for that study (december 2015) , fifteen rcts with 19,569 participants fulfilling the same eligibility criteria have been completed and analysed. [31] [32] [33] [34] [35] [36] [37] [38] [39] [40] [41] [42] [43] [44] [45] we therefore sought data from these more recent studies for inclusion in an updated metaanalysis of aggregate (trial-level) data to determine whether vitamin d reduced ari risk overall, and to evaluate whether effects of vitamin d on ari risk varied according to baseline 25(oh)d concentration and/or dosing regimen (frequency, dose size, and trial duration). . cc-by-nc-nd 4.0 international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted july 17, 2020. . https://doi.org/10.1101/2020.07.14.20152728 doi: medrxiv preprint methods were pre-specified in a protocol that was registered with the prospero ppi representatives were not involved in the conduct of this study. randomised, double-blind, trials of supplementation with vitamin d 3 , vitamin d 2 or 25(oh)d of any duration, with a placebo or low-dose vitamin d control, were eligible for inclusion if they had been approved by a research ethics committee and if data on incidence of ari were collected prospectively and pre-specified as an efficacy outcome. the latter requirement was imposed in order to minimise misclassification bias (prospectively designed instruments to capture ari events were deemed more likely to be sensitive and specific for this outcome). studies reporting results of longterm follow-up of primary rcts were excluded. . cc-by-nc-nd 4.0 international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. (which was not certified by peer review) the copyright holder for this preprint this version posted july 17, 2020. summary data from trials which contributed to our previous meta-analysis of individual participant data 30 were extracted from our central database, with permission from the principal investigators. summary data relating to the primary outcome (overall and by sub-group) and secondary outcomes (overall only) from newly identified trials were requested from principal investigators. on receipt, they were assessed for consistency with associated publications. study authors were contacted to provide missing data and to resolve any queries arising from these consistency checks. once queries had been resolved, clean summary data were uploaded to the study database, which was held in stata ic v14.2 (statacorp, college station, tx). data relating to study characteristics were extracted for the following variables: study setting, eligibility criteria, 25(oh)d assay and levels, details of intervention and control regimens, trial duration, case definitions for ari and number entering primary analysis (after randomisation). follow-up summary data were requested for the proportions of participants experiencing one or more ari during the trial, both overall and stratified by baseline serum 25(oh)d concentration, where this was available. we also requested summary data on the proportions of participants who experienced one or more of the following events during the trial: upper respiratory infection (uri); lower respiratory infection (lri); emergency department attendance and/or hospital admission for ari; death due to ari or respiratory failure; use of antibiotics to treat an ari; absence from work or school due to ari; a serious adverse event; death due to any cause; and potential adverse reactions to vitamin d (hypercalcaemia and renal stones). . cc-by-nc-nd 4.0 international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. (which was not certified by peer review) the copyright holder for this preprint this version posted july 17, 2020. . we used the cochrane collaboration risk of bias tool 46 to assess the following variables: sequence generation, allocation concealment, blinding of participants, personnel and outcome assessors, completeness of outcome data, evidence of selective outcome reporting and other potential threats to validity. study quality was assessed independently by two investigators (arm and daj), except for the five trials for which daj and/or arm were investigators, which were assessed by cac. discrepancies were resolved by consensus. the primary outcome of the meta-analysis was the proportion of participants experiencing one or more aris, with the definition of ari encompassing events classified as uri, lri and ari of unclassified location (i.e. infection of the upper and/or lower respiratory tract). secondary outcomes were incidence of uri and lri, analysed separately; incidence of emergency department attendance and/or hospital admission for ari; death due to ari or respiratory failure; use of antibiotics to treat an ari; absence from work or school due to ari; incidence of serious adverse events; death due to any cause; and incidence of potential adverse reactions to vitamin d (hypercalcaemia and renal stones). data were analysed by daj; results were checked and verified by jds. our metaanalysis approach followed published guidelines. 47 the primary comparison was of participants randomised to vitamin d vs. placebo: this was performed for all of the outcomes listed above. for trials that included higher-dose, lower-dose and placebo arms, data from higher-dose and lower-dose arms were pooled for analysis of the primary comparison. a secondary comparison of participants randomised to higher vs. lower doses of vitamin d was performed for the primary outcome only. a log odds ratio and its standard error was calculated for each outcome within each trial from the proportion of participants experiencing one or more events in the intervention vs. . cc-by-nc-nd 4.0 international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. (which was not certified by peer review) the copyright holder for this preprint this version posted july 17, 2020. . control arm. these were meta-analysed in a random effects model using the metan package 48 within stata ic v14.2 to obtain a pooled odds ratio with a 95% confidence interval and a measure of heterogeneity summarized by the i 2 statistic and its corresponding p value. the number needed to treat for an additional beneficial outcome (nnt) was calculated using the visual rx nnt calculator (http://www.nntonline.net/visualrx/) where meta-analysis of dichotomous outcomes revealed a statistically significant beneficial effect of allocation to vitamin d vs. placebo. to explore reasons for heterogeneity of effect of the intervention between trials we sub-optimal vitamin d status (so-called 'vitamin d insufficiency', 50-74.9 nmol/l). 49 an exploratory analysis restricted to studies with optimal frequency, dose size and duration was also performed. to investigate factors associated with heterogeneity of effect between subgroups of trials, we performed multivariable meta-regression analysis on trial-level characteristics, namely, dose frequency, dose size and trial duration, to produce an adjusted odds ratio, a 95% confidence interval and a p value for interaction for each factor. independent variables were dichotomised to create a more parsimonious model the meta-regression analysis excluded data from one trial that included higher-dose, lower-dose and placebo arms, 18 since the higher-dose and lower-dose arms spanned the 1,000 iu/day cut-off, rendering it unclassifiable for the purposes of this analysis. . cc-by-nc-nd 4.0 international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted july 17, 2020. . for the primary analysis, the likelihood of publication bias was investigated through the construction of a contour-enhanced funnel plot. 50 we used the five grade considerations (study limitations, consistency of effect, imprecision, indirectness and publication bias) 51 to assess the quality of the body of evidence contributing to analyses of the primary efficacy outcome and major secondary outcomes of our metaanalysis. we conducted two exploratory sensitivity analyses for the primary comparison of the primary outcome: one excluded rcts where risk of bias was assessed as being unclear; the other excluded rcts in which incidence of ari was not the primary or coprimary outcome. this study was conducted without external funding. . cc-by-nc-nd 4.0 international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted july 17, 2020. . the study selection process is illustrated in figure 1 compared effects of higher-dose, lower-dose and placebo arms, 18 21 24 41 and 5 compared effects of higher-vs. lower-dose regimens of vitamin d only. 29 32 34 35 37 aggregate data were sought and obtained for all but 1 study. 45 table s1 . characteristics of the 39 studies contributing data to this meta-analysis and their participants are presented in table 1 . trials were conducted in 17 different countries on 4 continents, and enrolled participants of both sexes from birth to 95 years of age. baseline serum 25(oh)d concentrations were determined in 32 of 39 trials: mean baseline 25(oh)d concentration ranged from 18.9 to 90.9 nmol/l (to convert to ng/ml, divide by 2.496). thirty-eight studies administered oral vitamin d 3 to participants in the intervention arm, while 1 study administered oral 25(oh)d. vitamin d was given as monthly to 3-monthly bolus doses in 12 studies; as weekly doses in 5 studies; as daily doses in 20 studies; and as a combination of bolus and daily doses in 2 studies. trial duration ranged from 8 weeks to 3 years. incidence of ari was primary or co-primary outcome for 21 studies, and a secondary outcome for 18 studies. details of the risk of bias assessment are provided in supplementary table s2 . two trials were assessed as being at unclear risk of bias due to high loss to follow-up. in the trial by laaksi and colleagues, 8 37% of randomised participants were lost to follow-. cc-by-nc-nd 4.0 international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted july 17, 2020. . up. in the trial by dubnov-raz and colleagues, 26 52% of participants did not complete all symptom questionnaires. all other trials were assessed as being at low risk of bias for all seven aspects assessed. table 2 ; cates plot, figure s1 ). heterogeneity of effect was moderate (i 2 40.0%, p for heterogeneity 0.009). the associated nnt was 36 (95% ci 20 to 206). for the secondary comparison of higher-vs. lower-dose vitamin d, we observed no statistically significant difference in the proportion of participants with at least one ari (or 0.86, 95% ci 0.71 to 1.04; 2,889 participants in 9 studies; i 2 8.0%, p for heterogeneity 0.37; figure s2 ). to investigate reasons for the observed heterogeneity of effect for the primary comparison of vitamin d vs. placebo control, we stratified this analysis by one participant-level factor (baseline vitamin d status) and by three trial-level factors (dose frequency, dose size, and trial duration). results are presented in table 2 figure s3 ). with regard to dosing frequency, a statistically significant protective effect was seen for trials where vitamin d was given daily (or 0.75, 95% ci 0.61 to 0.93; 4,005 participants in 18 studies), but not for trials in which it was given weekly (or 0.97, 95% ci 0.88 to 1.06; 12,562 participants in 5 studies), or monthly to 3-monthly (or 1.00, 95% ci 0.91 to 1.09; 11,248 participants in 11 studies; figure . cc-by-nc-nd 4.0 international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted july 17, 2020. . s4). statistically significant protective effects of the intervention were also seen in trials where vitamin d was administered at daily equivalent doses of 400-1000 iu ( figure s5 ). statistically significant protective effects were also seen for trials with a duration of ≤ 12 months (or 0.82, 95% ci 0.72 to 0.94; 9,061 participants in 28 studies) but not in those lasting >12 months (or 1.03, 95% ci 0.95 to 1.11; 18,754 participants in 6 studies; figure s6 ). an exploratory analysis restricted to placebo-controlled trials investigating effects of daily dosing at doses of 400-1000 iu/day with duration ≤ 12 months showed a statistically significant reduction in the proportion of participants experiencing at least one ari (or 0.58, 95% ci 0.45 to 0.75; 1,232 participants in 8 studies; figure s7 ; cates plot, figure s1 ). heterogeneity of effect was low (i 2 0.0%, p for heterogeneity 0.67). the associated nnt was 8 (95% ci 6 to 15). multivariable meta-regression analysis of trial-level sub-groups did not identify a statistically significant interaction between allocation to vitamin d vs. placebo and dose frequency, size or trial duration (table s3) . meta-analysis of secondary outcomes was performed for results of placebo-controlled trials only; results are presented in table 3 . overall, without consideration of participant-or trial-level factors, vitamin d supplementation did not have a statistically significant effect on the proportion of participants with one or more uri, lri, courses of antimicrobials for ari, work/school absences due to ari, hospitalisations or emergency department attendances for ari, serious adverse events of any cause, death due to ari or respiratory failure, death due to any cause, or episodes of hypercalcaemia or renal stones. . cc-by-nc-nd 4.0 international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted july 17, 2020. . https://doi.org/10.1101/2020.07.14.20152728 doi: medrxiv preprint a funnel plot for the proportion of participants experiencing at least one ari showed left-sided asymmetry, raising the possibility that small trials showing non-protective effects of vitamin d may not have been included in the meta-analysis ( figure s8 ). an egger's regression test for publication bias 52 confirmed asymmetry (p=0.002). accordingly, the quality of the body of evidence contributing to analyses of the primary efficacy outcome and major secondary outcomes was downgraded to moderate (table s4 ). results of exploratory sensitivity analyses are presented in table s5 . meta-analysis of the proportion of participants in placebo-controlled trials experiencing at least one ari, excluding 2 studies assessed as being at unclear risk of bias, 8 pandemic, we used a trial-level approach for this update, which includes data from a total of 29,841 participants in 39 trials. overall, we report a modest statistically significant protective effect of vitamin d supplementation, as compared with placebo (or 0.89, 95% ci 0.81 to 0.98). as expected, there was significant heterogeneity (p=0.009) across trials, which might have led to an under-estimate of the protective effect. on the other hand, a funnel plot revealed evidence of publication bias, which might have led to an over-estimate of the protective effect. in contrast to findings of our . cc-by-nc-nd 4.0 international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted july 17, 2020. . previous meta-analysis, 30 we did not observed enhanced protection in those with the lowest 25(oh)d levels at baseline. however, there was evidence that efficacy of vitamin d supplementation varied according to dosing regimen and trial duration, with protective effects associated with daily administration of doses of 400-1000 iu vitamin d given for ≤ 12 months. an exploratory analysis restricted to data from 8 trials fulfilling these design criteria revealed a larger protective effect (or 0.58, 95% ci 0.45 to 0.75) without significant heterogeneity across trials (p for heterogeneity 0.67). the magnitude of the overall protective effect seen in the current analysis (or 0.89, 95% ci 0.81 to 0.98) is similar to the value reported in our previous meta-analysis of individual participant data (adjusted or 0.88, 95% ci 0.81 to 0.96). 30 in keeping with our previous study, the point estimate for this effect was lower among those with baseline 25(oh)d <25 nmol/l than in those with higher baseline vitamin d status. however, in contrast to our previous finding, a statistically significant protective effect of vitamin d was not seen in those with the lowest 25(oh)d concentrations. this difference reflects the inclusion of null data from three new rcts in which vitamin d was given in relatively high doses at weekly or monthly intervals over 2-3 years. 40 42 44 null results of these studies contrast with protective effects reported from earlier trials in which smaller daily doses of vitamin d were given over shorter periods. 8 9 13 16 these differing findings suggest that the frequency, amount and duration of vitamin d supplementation may be key determinants of its protective efficacy. in keeping with this hypothesis, statistically significant protective effects of vitamin d were seen for meta-analysis of trials where vitamin d was given daily; where it was given at doses of 400-1000 iu/day; and where it was given for 12 months or less. when results of trials that investigated daily administration of 400-1000 iu over ≤ 12 months were pooled in an exploratory meta-analysis, a protective effect was seen (or 0.58, 95% ci 0.45 to 0.75) with low heterogeneity (i 2 0.0%, p for heterogeneity 0.67) and a nnt of 8 (95% ci 6 to 15). the current study has several strengths: it contains the very latest rct data available in this fast-moving field, including findings from a soon-to-be published very large trial conducted using directly-observed, higher-dose, weekly vitamin d supplementation in very deficient children. 42 the inclusion of additional studies allowed us to analyse results of placebo-controlled studies vs. high-dose / low-dose studies separately, and . cc-by-nc-nd 4.0 international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted july 17, 2020. . https://doi.org/10.1101/2020.07.14.20152728 doi: medrxiv preprint gave us the power to investigate reasons for heterogeneity of effect observed across trials. for example, we could distinguish the effects of daily vs. weekly dosing, which were previously pooled. 30 our work also has limitations. given the need to generate a rapid update of our previous work in the context of the covid-19 pandemic, we meta-analysed aggregate (trial-level) data, rather than individual participant data; this allowed us to proceed rapidly, without the delays introduced by the need to establish multiple data sharing agreements. however, we did contact authors to get unpublished estimates of effect that were stratified by pre-defined baseline 25(oh)d levels, harmonised across studies: thus, we were able to provide accurate data for the major participant-level effect-modifier of interest. despite the large number of trials overall, relatively few compared effects of lower-vs. higher-dose vitamin d: our power for this secondary comparison was therefore limited. we lacked the individual participant data to investigate race/ethnicity and obesity as potential effect-modifiers. we also could not account for other factors that might influence the efficacy of vitamin d supplements for ari prevention (e.g., taking the supplement with or without food) or secular trends that would influence trials, such as the increased societal use of vitamin d supplements; 53 concurrent use of standard dose vitamin d supplements or multivitamins in the "placebo" group would effectively render these as high-vs. low-dose trials and potentially drive results toward the null. a final limitation relates to the funnel plot, which suggests that the overall effect size may have been over-estimated due to publication bias. in summary, this updated meta-analysis of data from rcts of vitamin d for the prevention of ari showed a statistically significant overall protective effect of the intervention. the number needed to treat to prevent one ari was 36. the protective effect was heterogenous across trials; it also may have been over-estimated due to publication bias. in contrast to findings of our previous meta-analysis of individual participant data, we did not see a protective effect of vitamin d supplementation among those with the lowest baseline vitamin d status. the vitamin d dosing regimen of most benefit was daily and used standard doses (e.g., 400 to 1000 iu) for up to 12 months. the relevance of these findings to covid-19 is not known and requires investigation. . cc-by-nc-nd 4.0 international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted july 17, 2020. . https://doi.org/10.1101/2020.07.14.20152728 doi: medrxiv preprint . cc-by-nc-nd 4.0 international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted july 17, 2020. . this study was conducted without external funding. daj is supported by a barts students. the views expressed are those of the authors and not necessarily those of barts charity or the office for students. sources of support for individual trials are detailed in supplementary material. we thank dr emma c goodall (glaxosmithkline plc) for contributing data. we also thank all the people who participated in primary randomised controlled trials, and the teams who conducted them. daj and arm wrote the study protocol and designed statistical analyses. daj, cac and arm assessed eligibility of studies for inclusion and performed risk of bias assessments. statistical analyses were done by daj; results were checked and verified by jds. daj and arm wrote the first draft of the report. all authors revised it critically for important intellectual content, gave final approval of the version to be published, and agreed to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work were appropriately investigated and resolved. all authors have completed the icmje uniform disclosure form. no author has had any financial relationship with any organisations that might have an interest in the submitted work in the previous three years. no author has had any other relationship, or undertaken any activity, that could appear to have influenced the submitted work. daj and arm are the manuscript's guarantors and they affirm that this is an honest, accurate, and transparent account of the study being reported and that no important aspects of the study have been omitted. all analyses were pre-specified in the study protocol, other than the exploratory analyses whose results are presented in table s5 and figure s7 . data sharing: the study dataset is available from d.a.jolliffe@qmul.ac.uk. . cc-by-nc-nd 4.0 international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted july 17, 2020. . is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted july 17, 2020. . is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted july 17, 2020. is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted july 17, 2020. is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted july 17, 2020. . https://doi.org/10.1101/2020.07.14.20152728 doi: medrxiv preprint figure 1 : flow chart of study selection . cc-by-nc-nd 4.0 international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. (which was not certified by peer review) the copyright holder for this preprint this version posted july 17, 2020. . . cc-by-nc-nd 4.0 international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. (which was not certified by peer review) the copyright holder for this preprint this version posted july 17, 2020. . vitamin d and sars-cov-2 virus/covid-19 disease modulation of the immune response to respiratory viruses by vitamin d vitamin d in the prevention of acute respiratory infection: systematic review of clinical studies acute respiratory tract infection and 25-hydroxyvitamin d concentration: a systematic review and meta-analysis a randomized controlled trial of vitamin d3 supplementation for the prevention of symptomatic upper respiratory tract infections randomized trial of vitamin d supplementation to prevent seasonal influenza a in schoolchildren effects of vitamin d supplementation to children diagnosed with pneumonia in kabul: a randomised controlled trial vitamin d supplementation for the prevention of acute respiratory tract infection: a randomized, double-blinded trial among young finnish men vitamin d supplementation in children may prevent asthma exacerbation triggered by acute respiratory infection effect of weekly vitamin d supplements on mortality, morbidity, and growth of low birthweight term infants in india up to age 6 months: randomised controlled trial high doses of vitamin d to reduce exacerbations in chronic obstructive pulmonary disease: a randomized trial effect on the incidence of pneumonia of vitamin d supplementation by quarterly bolus dose to infants in kabul: a randomised controlled superiority trial randomized trial of vitamin d supplementation and risk of acute respiratory infection in mongolia effect of vitamin d3 supplementation on upper respiratory tract infections in healthy adults: the vidaris randomized controlled trial vitamin d3 supplementation in patients with frequent respiratory tract infections: a randomised and double-blind intervention study vitamin d supplementation reduces the risk of acute otitis media in otitis-prone children vitamin d3 supplementation and upper respiratory tract infections in a randomized, controlled trial effect of vitamin d supplementation on antibiotic use: a randomized controlled trial vitamin d3 and gargling for the prevention of upper respiratory tract infections: a randomized controlled trial effects of vitamin d supplements on influenza a illness during the 2009 h1n1 pandemic: a randomized controlled trial reduced primary care respiratory infection visits following pregnancy and infancy vitamin d supplementation: a randomised controlled trial vitamin d3 supplementation in patients with chronic obstructive pulmonary disease (vidico): a multicentre, double-blind, randomised controlled trial. the lancet respiratory medicine double-blind randomised placebocontrolled trial of bolus-dose vitamin d3 supplementation in adults with asthma (vidias) double-blind randomised controlled trial of vitamin d3 supplementation for the prevention of acute respiratory infection in older adults and their carers (vidiflu) weekly cholecalciferol supplementation results in significant reductions in infection risk among the vitamin d deficient: results from the cipris pilot rct vitamin d supplementation and upper respiratory tract infections in adolescent swimmers: a randomized controlled trial vitamin d supplementation and the risk of colds in patients with asthma improved control of childhood asthma with low-dose, short-term vitamin d supplementation: a randomized, double-blind, placebo-controlled trial high-dose monthly vitamin d for prevention of acute respiratory infection in older long-term care residents: a randomized clinical trial vitamin d supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data vitamin d supplementation for treatment and prevention of pneumonia in under-five children: a randomized double-blind placebo controlled trial effect of high-dose vs standard-dose wintertime vitamin d supplementation on viral upper respiratory tract infections in young healthy children randomized trial of vitamin d supplementation to prevent seasonal influenza and upper respiratory infection in patients with inflammatory bowel disease effect of vitamin d supplementation on recurrent wheezing in black infants who were born preterm: the d-wheeze randomized clinical trial randomized phase 2 trial of monthly vitamin d to prevent respiratory complications in children with sickle cell disease effect of vitamin d supplementation to reduce respiratory infections in children and adolescents in vietnam: a randomized controlled trial. influenza other respir viruses effect of higher vs standard dosage of vitamin d3 supplementation on bone strength and infection in healthy infants: a randomized clinical trial intake of 25-hydroxyvitamin d3 reduces duration and severity of upper respiratory tract infection: a randomized, double-blind, placebo-controlled, parallel group comparison study vitamin d and acute respiratory infections-the poda trial effect of monthly high-dose vitamin d supplementation on acute respiratory infections in older adults: a randomized controlled trial winter cholecalciferol supplementation at 55 degrees n has little effect on markers of innate immune defense in healthy children aged 4-8 years: a secondary analysis from a randomized controlled trial vitamin d supplements and prevention of tuberculosis infection and disease occurrence of infections in schoolchildren subsequent to supplementation with vitamin d-calcium or zinc: a randomized, doubleblind, placebo-controlled trial high-dose oral vitamin d supplementation and mortality in people aged 65-84 years: the vidal cluster feasibility rct of open versus doubleblind individual randomisation impact of two oral doses of 100,000 iu of vitamin d3 in preschoolers with viral-induced asthma: a pilot randomised controlled trial the cochrane collaboration's tool for assessing risk of bias in randomised trials cochrane handbook for systematic reviews of interventions version 6 metan: stata module for fixed and random effects meta-analysis, revised 23 diagnosis and management of vitamin d deficiency contour-enhanced meta-analysis funnel plots help distinguish publication bias from other causes of asymmetry grade: an emerging consensus on rating quality of evidence and strength of recommendations bias in meta-analysis detected by a simple, graphical test longitudinal and secular trends in dietary supplement use: nurses' health study and health professionals follow-up study pharmacokinetics of oral vitamin d(3) and calcifediol key: cord-295414-v10454ns authors: baktash, vadir; hosack, tom; patel, nishil; shah, shital; kandiah, pirabakaran; van den abbeele, koenraad; mandal, amit k j; missouris, constantinos g title: vitamin d status and outcomes for hospitalised older patients with covid-19 date: 2020-08-26 journal: postgrad med j doi: 10.1136/postgradmedj-2020-138712 sha: doc_id: 295414 cord_uid: v10454ns purpose: older adults are more likely to be vitamin d deficient. the aim of the study was to determine whether these patients have worse outcomes with covid-19. methods: we conducted a prospective cohort study between 1 march and 30 april 2020 to assess the importance of vitamin d deficiency in older patients with covid-19. the cohort consisted of patients aged ≥65 years presenting with symptoms consistent with covid-19 (n=105). all patients were tested for serum 25-hydroxyvitamin d (25(oh)d) levels during acute illness. diagnosis of covid-19 was confirmed via viral reverse transcriptase pcr swab or supporting radiological evidence. covid-19-positive arm (n=70) was sub-divided into vitamin d-deficient (≤30 nmol/l) (n=39) and -replete groups (n=35). subgroups were assessed for disease severity using biochemical, radiological and clinical markers. primary outcome was in-hospital mortality. secondary outcomes were laboratory features of cytokine storm, thoracic imaging changes and requirement of non-invasive ventilation (niv). results: covid-19-positive arm demonstrated lower median serum 25(oh)d level of 27 nmol/l (iqr=20–47 nmol/l) compared with covid-19-negative arm, with median level of 52 nmol/l (iqr=31.5–71.5 nmol/l) (p value=0.0008). among patients with vitamin d deficiency, there was higher peak d-dimer level (1914.00 μgfeu/l vs 1268.00 μgfeu/l) (p=0.034) and higher incidence of niv support and high dependency unit admission (30.77% vs 9.68%) (p=0.042). no increased mortality was observed between groups. conclusion: older adults with vitamin d deficiency and covid-19 may demonstrate worse morbidity outcomes. vitamin d status may be a useful prognosticator. the covid-19 outbreak, which began in china in late 2019 and then rapidly spread across the world, has spurred a global effort to tackle the disease and establish risk factors and prognostic markers; one such is serum vitamin d deficiency. vitamin d is a secosteroid with varied immunomodulatory, antiinflammatory, antifibrotic and antioxidant actions. there is growing evidence that it may play a role in the pathophysiological processes of the relationship between vitamin d deficiency and adverse prognosis has been suggested by the apparent northern-southern latitude gradient, with mortality and hospitalisation rates for covid-19 seen to be higher in northern latitude countries compared with those closer to the equator. 1 furthermore, research by alipio and colleagues 2 , in a retrospective study, provides evidence of an association between vitamin d deficiency and adverse outcome in patients with covid-19. older adults in institutions, such as hospitals and care homes, are particularly likely to be vitamin d deficient as a result of a lack of sun exposure and dietary insufficiency, and may have worse outcomes with covid19. in the uk, the royal college of physicians of london commentary 3 reported that patients who died of covid-19 were severely vitamin d deficient. there is also growing concern that the black, asian and minority ethnic community who produce less vitamin d as a result of higher skin melanin content are inherently more susceptible to severe presentations of covid-19. 4 therefore, the british nutrition found 2 ation, 5 who applied guidance to the public amidst self-isolation for covid19 , has suggested that everyone should consider taking a daily supplement of 400 iu of vitamin d. we investigated serum vitamin d levels in older patients admitted to our institution during the pandemic. the aim of our study was to assess the potential relationship between vitamin d deficiency and covid-19 severity in hospitalised older adults. we conducted a single-centred prospective cohort study of older patients admitted to a large district general hospital in the uk, with symptoms in keeping with a viral infection. patients were divided into covid-19-positive and -negative groups with subsequent assessment of vitamin d status. a subgroup analysis of the covid-19-positive arm was conducted with analysis of serum markers of infection and clinical markers of disease severity, such as high dependency unit (hdu) admission and non-invasive ventilation (niv). all emergency admissions aged ≥65 years admitted to our hospital with symptoms consistent with covid-19 including cough, dyspnoea, fever and/ or anosmia 6 between 1 march and 30 april 2020 were included in the study (figure 1). these patients were investigated with real-time reverse transcriptase-pcr (rt-pcr) assay for severe acute respiratory syndrome coronavirus-2 (sars-cov-2) on nasopharyngeal swab, blood tests including vitamin d levels (25-hydroxyvitamin d (25(oh)d), basic observations, and chest x-ray (cxr) and/or chest ct. diagnosis of active sars-cov-2 infection was based on positive viral rt-pcr swab or evidence of covid-19 on a chest radiograph or chest ct (bilateral peripheral infiltrates/groundglass opacities, airspace opacification, traction bronchiectasis, inter/intralobular septal thickening and organising pneumonia). patients who did not meet either of these criteria were enrolled into the covid-19-negative group. the covid-19-positive group was divided into vitamin d-deficient (≤30 nmol/l) and -replete (>30 nmol/l) groups, as per national guidelines and local laboratory standards. 7 vitamin d-deficient patients were supplemented in accordance with national guidelines and all patients received care in line with best practice guidance. in addition, patients were treated with subcutaneous low-molecular-weight heparin venous thromboembolism (vte) prophylaxis as per national guidance. data were extracted from medical notes and the local hospital electronic database. these included age, weight, height, ethnicity, smoking status and comorbidities. ethnicities were self-assigned. rockwood clinical frailty score 8 and charlson comorbidity index 9 were calculated retrospectively. the primary outcome measured was in-hospital mortality secondary to covid-19. secondary outcomes were defined as niv support and admission to hdu, covid-19 radiographic changes on cxr and laboratory features of cytokine storm. all patients had vitamin d levels checked in keeping with good medical practice. biochemical/haematological panels (c reactive protein (crp), d-dimer, ferritin, high sensitivity troponin t, lactate dehydrogenase (ldh) and lymphocyte count) were carried out in accordance with local guidance on covid-19 diagnostics and prognostication. 10 in addition, data for specific features consistent with the covid-19 11 12 were collected from formal reports of cxr and/or chest ct. causes of death were obtained digitally from mortality reports made by our hospital's mortality and bereavement office. all statistical analyses were carried out on graphpad prism (version 8). for continuous outcome variables, each data set was assessed for normality using kolmogorov-smirnov and shapiro-wilk tests, and tested for significance with either an unpaired t-test if parametric or a mann-whitney test if non-parametric. possible outcome sets were normalised by logarithmic transformation and tested for significance using a parametric method. for categorical variables, an or was calculated and tested for significance using a pearson ᵡ² test. p value <0.05 (two-tailed test) was considered to be statistically significant. in addition, all variables underwent a pearson and spearman analysis to gauge linear covariance between the outcome measures and the corresponding serum vitamin d concentration. for binary outcomes, a receiver operating characteristic (roc) curve was plotted to assess the prognostic value of serum concentrations of vitamin d. area under the curve (auc) values >0.5 were deemed to convey a prognostic value in the measured variable. this survey was approved by the trust audit department with reference fh119 and with clinically collected, non-identifiable data which does not fall under the remit of nhs research ethics committee. all data were collected locally and handled in accordance with european general data protection regulation (gdpr) standards, as well as local and nhs standards on data protection. all practices conducted as part of this study were done in accordance with local regulations and best clinical practice protocols. serum vitamin d levels were tested alongside the hospital routine serum covid-19 panel and did not require any extra phlebotomy. patients received care in line with standard practices for the management of covid-19 throughout the study period. a total of 105 patients (mean age 81 years, range 65-102; male (n=57):female (n=48)) were recruited to the study, with 70 (66.7%) subsequently allocated to the covid-19-positive group and 35 (33.3%) allocated to the covid-19-negative group. among the covid-19-positive group, 39 (55.7%) patients were found to have 25(oh)d level ≤30 nmol/l and 31 (44.3%) were found to have a level >30 nmol/l. demographics (age, sex, ethnicity, frailty, body mass index, smoking history and comorbidities) between covid-19-positive and -negative groups were comparable. in addition, the characteristics of vitamin d-replete anddeficient groups in the covid-19-positive arm were found to be comparable (table 1) . only three patients were admitted from a nursing home with one instance in each of the three study subgroups. no patients were admitted to the intensive treatment unit, and ceilings of care were set to niv support on the hdu. there was no difference in the average length of stay between vitamin d subgroups (29 days). vitamin d levels in the covid-19-positive group were overall significantly lower compared with that in the covid-19-negative group (27.00 nmol/l vs 52.00 nmol/l) (p=0.0008). among patients with vitamin d deficiency in the covid-19-positive group, there was a higher average peak in d-dimer level (1914.00 μgfeu/l vs 1268.00 μgfeu/l) (p=0.034) and a higher incidence of niv support and hdu admission (30.77% vs 9.68%) (p=0.042). the vitamin d-deficient case group demonstrated higher peak crp, ldh and ferritin levels; lower trough lymphocyte counts; and increased incidence of radiographic changes, although these were not statistically significant. the vitamin d-replete case group demonstrated a higher peak troponin level that was not statistically significant (table 2) . there was only one confirmed case of pulmonary thrombosis in the vitamin d-deficient case group. there was no apparent difference in mortality between the two groups. ethnicity did not influence outcomes in this cohort. the outcome measures did not appear to follow a linear relationship with serum vitamin d concentrations. roc curves were plotted for vitamin d as a distinguisher between covid-19-positive and -negative states as well as between those requiring and not requiring ventilatory support (figure 2). for the former, auc was 0.70 (95% ci 0.59 to 0.80) (p value=0.0009). for the latter, auc was 0.67 (95% ci 0.54 to 0.80) (p value=0.046). the main findings of our study suggest that older patients with lower serum concentrations of 25(oh)d, when compared with aged-matched vitamin d-replete patients, may demonstrate worse outcomes from covid-19. markers of cytokine release syndrome were raised in these patients and they were more likely to become hypoxic and require ventilatory support in hdu. there was no difference in mortality between groups. evidence of an association between vitamin d deficiency and adverse outcome in covid-19 is provided by alipio (2020) and d'avolio and colleagues. 13 the former study (preprint) observed an increased disease severity for patients with vitamin d deficiency, while the latter noted a decreased serum vitamin d concentration between covid-19-positive and -negative patients. these were both retrospective cohort studies encompassing a sample size of 212 and 120, respectively. ilie and colleagues 14 performed a meta-analysis to study the association of vitamin d and morbidity and mortality with covid-19 in 20 european countries and proposed a possible correlation between vitamin d levels, the incidence of sars-cov-2 infection and mortality. hastie and colleagues 15 used biobank data on 449 people with confirmed sars-cov-2 infection and found no relationship with serum 25(oh)d concentrations. the average age of subjects in this study was 49 years, and a major limitation was utilisation of historical vitamin d levels of patients (between 2006 and 2010) rather than vitamin d status at the time of infection with sars-cov-2. in our study, the average age was older at 81 years and we were able to establish vitamin d status during active sars-cov-2 infection. in non-communicable diseases, both viral and bacterial, vitamin d deficiency has been associated with increased morbidity and mortality as well as a higher incidence of acute respiratory distress syndrome in critically unwell patients. 16 17 whether low vitamin d levels are cause or consequence of disease (reverse causality) processes remains unclear. however, a meta-analysis performed in 2017 of 11 321 patients from 25 randomised controlled studies demonstrated that vitamin d supplementation protected against acute respiratory tract infection and patients with very low concentrations of 25(oh)d (<25 nmol/l) benefiting most. 18 cited markers of cytokine storm were elevated in our vitamin d deficiency subset of patients, and the high peak d-dimer concentration was deemed statistically significant (p=0.034). this was found in the absence of in situ pulmonary thrombosis and in the context of standard vte prophylaxis. several studies have explored 19 20 the pro-thrombotic state induced during the cytokine storm phase of inflammatory lung disease. the coagulation system appears active in critically ill patients, and high d-dimer levels reflect activation of the proinflammatory cytokine cascade (and downregulation of the anti-inflammatory cytokine cascade). elevated d-dimer levels are associated with amplified risk for multiple organ failure and death. 21 this may explain the increased incidence of ventilatory support seen in vitamin d-deficient patients. vitamin d has been shown to condition the innate immune reaction against both bacterial and viral infections. calcitriol (1,25(oh) 2 d 3 ), the active form of vitamin d, modulates macrophage activity by inhibiting the release of proinflammatory cytokines such as interleukin (il)-1, il-6, il-8, il-12 and tumour necrosis factor-alpha. 16 vitamin d shifts the adaptive immune reaction from a th1 to a th2 phenotype, 17 22 downregulating differentiation of naïve t cells into pro-inflammatory th17 cells, 23 24 and promotes t regulatory cell induction. [25] [26] [27] dysregulation of both innate and adaptive immunity, as a result of vitamin d deficiency, may therefore be central to precipitating the 'cytokine storm' seen in covid-19 infection. in addition to anti-inflammatory properties, vitamin d also exerts a protective effect on human alveolar epithelial cells by promoting wound repair. 28 vitamin d has also been shown to preserve endothelial integrity and deficiencies result in increased vascular permeability and leak. 29 vitamin d also increases the expression of ace-2. while increased ace-2 expression in the early pandemic was predicted to increase the risk of infection, paradoxically, ace-2 has also been shown to protect against acute lung injury. 14 30 disruption of one or more of these defensive pathophysiological processes may explain the association we found between vitamin d deficiency and increased requirement of ventilatory support. whether this actually represents a causal relationship has not yet been elucidated. as a single-centre study at a district general hospital, we cannot generalise our results to other settings. furthermore, our trust is based in southern england, where population demographics and socioeconomic status may differ from those elsewhere. we acknowledge that extracting information from medical notes requires second-hand interpretation and may not be representative of the full clinical picture. patient outcomes may also have been influenced by current guidelines imposed by the national institute of clinical excellence committee. 31 we also acknowledge the role that sunlight exposure may have played in the measured serum levels of 25(oh)d. unfortunately, this could not reliably be measured in patients; however, efforts were made to account for this. notably, the study was carried out within a 2-month period which attenuated potential weather influence on sunlight exposure. in addition, the housing status of patients was considered-only three nursing home residents were included in the study, which minimised the risk of institutionalisation and its association with reduced sun exposure bearing influence on the results. considerations were made for the utilisation of sample size calculations to ensure the study was powered appropriately. no limit was initially set for sample size; however, the final number was limited by the dwindling numbers of patients with covid-19. despite achieving significant results in several outcomes, we acknowledge the risk of a type 2 error occurring with our experimental sample size. therefore, we were unable to discount an association between vitamin d deficiency and those variables which did not achieve statistical significance with observed effect sizes. length of stay was recorded for all patients in the covid-19 arm of the study, with no difference found between vitamin d subgroups. we emphasise, however, concerns on the reliability of this measure. given the geriatric population of our study sample, the overwhelming issues affecting hospital discharge were social and housing issues. this was further complicated by infection control measures during the pandemic limiting the ability of some families to receive their relatives back home. therefore, any firm conclusions should not be drawn from this outcome measure. another issue of consideration was vitamin d replacement and the effect this may have on the outcome measures recorded. in our study, vitamin d supplementation was only initiated after the acute phase of illness. given that steady-state serum concentrations of vitamin d are achieved after 3-6 months with replacement, 32 it is unlikely that serum levels would significantly change during the infective and symptomatic phase of admission. consequently, we do not believe this would have influenced outcome measures. we were also unable to establish whether vitamin d replacement during active sars-cov-2 infection results in favourable outcomes. our study has demonstrated that patients over the age of 65 years presenting with symptoms consistent with covid-19 are more likely to be vitamin d deficient. there appears to be a clinically relevant association between this and elevated markers of cytokine release syndrome and increased risk of respiratory failure requiring ventilatory support. although there was no apparent mortality difference between the two groups, this may reflect the overall poor prognosis associated with the higher prevalence of frailty and comorbidities in our older cohort of patients. vitamin d status may be a prognosticator for covid-19, and supplementation might improve outcomes. further studies in all age groups are awaited to validate this. contributors all authors contributed to the manuscript. all were involved in the design of the study. vb, pk and np collected the data. vb and th were responsible for the statistical analysis. vb, th, akjm, kvda, ss and cgm wrote the manuscript and all authors were involved in the final approval of the manuscript. funding this research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors. competing interests all authors understand the policy of declaration of interests. cgm is a former member of the fellowship of postgraduate medicine (fpm) council and is currently an fpm fellow. vb, th, np, ss, pk, kvda, akjm all declare that they have no competing interests. patient consent for publication not required. ethics approval as an audit using clinically collected, non-identifiable data, this work does not fall under the remit of national health service research ethics committees. this statement is also present in the 'methods and material' section of our manuscript. provenance and peer review not commissioned; externally peer reviewed. data availability statement data are available upon reasonable request. this article is made freely available for use in accordance with bmj's website terms and conditions for the duration of the covid-19 pandemic or until otherwise determined by bmj. you may use, download and print the article for any lawful, noncommercial purpose (including text and data mining) provided that all copyright notices and trade marks are retained. amit k j mandal http://orcid.org/0000-0003-0986-5927 • older patients with covid-19 infection and vitamin d deficiency (≤30 nmol/l) have higher peak d-dimer level and higher incidence of niv support and hdu admission. • vitamin d deficiency may be associated with worse outcomes from covid-19, and vitamin d status may be a useful prognosticator. what is already known on the subject • there appears to be an association between increased covid-19 incidence and mortality and countries with an increased prevalence of vitamin d deficiency. • vitamin d plays an important role in the modulation of the immune system through promotion of anti-inflammatory cytokines and down-regulation of pro-inflammatory t cells. • the occurrence of an inflammatory 'cytokine storm' during has been associated with poorer outcomes and increased disease severity. covid-19, and vitamin d vitamin d supplementation could possibly improve clinical outcomes of patients infected with coronavirus-2019 (covid-2019) mechanisms underlying the effect of vitamin d on the immune system british nutrition foundation. bnf busts the myths on nutrition and covid-19. 2020 covid-19: investigation and initial clinical management of possible cases controversies in vitamin d: summary statement from an international conference global clinical measure of fitness and frailty in elderly people a new method of classifying prognostic comorbidity in longitudinal studies: development and validation laboratory abnormalities in patients with covid-2019 infection frequency and distribution of chest radiographic findings in covid-19 positive patients radiological findings from 81 patients with covid-19 pneumonia in wuhan, china: a descriptive study 25-hydroxyvitamin d concentrations are lower in patients with positive pcr for sars-cov-2 the role of vitamin d in the prevention of coronavirus disease 2019 infection and mortality vitamin d concentrations and covid-19 infection in uk biobank 25-dihydroxyvitamin d3 inhibits cd40l-induced pro-inflammatory and immunomodulatory activity in human monocytes inhibition of th1 development and treatment of chronic-relapsing experimental allergic encephalomyelitis by a non-hypercalcemic analogue of 1,25-dihydroxyvitamin d(3) vitamin d supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individuals participant data coagulation abnormalities and thrombosis in patients with covid-19 covid-19 cytokine storm: the interplay between inflammation and coagulation. the lancet respiratory medicine d-dimer correlates with proinflammatory cytokine levels and outcomes in critically ill patients 25-dihydroxyvitamin d3 has a direct effect on naive cd4(+) t cells to enhance the development of th2 cells calcitriol suppresses antiretinal autoimmunity through inhibitory effects on the th17 effector response immune modulatory treatment of trinitrobenzene sulfonic acid colitis with calcitriol is associated with a change of a t helper (th) 1/th17 to a th2 and regulatory t cell profile in vitro generation of interleukin 10-producing regulatory cd4(+) t cells is induced by immunosuppressive drugs and inhibited by t helper type 1 (th1)-and th2-inducing cytokines topically applied 1,25-dihydroxyvitamin d3 enhances the suppressive activity of cd4+cd25+ cells in the draining lymph nodes expression of the inhibitory receptor ilt3 on dendritic cells is dispensable for induction of cd4+foxp3+ regulatory t cells by 1,25-dihydroxyvitamin d3 vitamin d deficiency contributes directly to the acute respiratory distress syndrome (ards) dietary vitamin d and its metabolites non-genomically stabilize the endothelium angiotensin-converting enzyme 2 in lung diseases covid-19 rapid guideline: critical care in adults national osteoporosis society practical clinical guideline on vitamin d and bone health key: cord-016130-5q9ufu28 authors: linday, linda a. title: nutritional supplements and upper respiratory tract illnesses in young children in the united states date: 2010-12-17 journal: preventive nutrition doi: 10.1007/978-1-59259-880-9_21 sha: doc_id: 16130 cord_uid: 5q9ufu28 key points: in the united states, children have lower blood levels than adults of eicosapentaenoic acid (epa), an important ω-3 fatty acid that helps decrease inflammation; vitamin a, the “anti-infective” vitamin; and selenium (se), a trace metal that is an intrinsic part of glutathione peroxidase, an important free-radical scavenging enzyme. epa, vitamin a, and se are important in controlling inflammation and can be supplied by oral nutritional supplements. cod liver oil contains epa (and other important ω-3 fatty acids), and vitamin a as well as vitamin d. fish oil contains ω-3 fatty acids (including epa) but no vitamins. our clinical research demonstrates that daily supplementation with a flavored cod liver oil (which meets european purity standards) and a children’s multivitamin-mineral with trace metals, including se, can decrease morbidity from upper respiratory tract illnesses, otitis media, and sinusitis in young children living in the united states. these supplements can be used by practitioners on an individual basis, when clinically indicated; the supplements can be purchased in the united states without a prescription. socioeconomically disadvantaged children are at risk for micronutrient deficiencies. however, their families may not be able to afford to purchase these supplements, which are not available through medicaid, the special supplemental nutrition program for women, infants and children, or the food stamp program. if our results are confirmed in larger studies, a system change will be needed to provide these supplements to nutritionally vulnerable, socioeconomically disadvantaged children living in the united states. key element in the pathophysiology of these disorders. this chapter discusses the role of essential fatty acids, vitamins, and trace metals in the pathophysiology of inflammation; reviews our clinical research on the use of a lemon-flavored cod liver oil (which meets european purity standards) and a children's chewable multivitamin-mineral with se for the prevention and adjunctive treatment of these disorders; reviews the history of cod liver oil, including its importance in the discovery of vitamin d and the anti-infective properties of vitamin a; and discusses the current clinical use of these supplements. if additional research confirms the utility of these supplements in improving the health of young children, the problem of access to these supplements by socioeconomically disadvantaged children in the united states will need to be addressed. children under age 5 yr had an average of 20.7 million ambulatory care visits per year for upper respiratory conditions in the united states from 1993 to 1995, with another 14.5 million visits per year for om during the same time period (1) . in addition to their cost, unnecessary health care visits for the treatment of colds generate a significant number of inappropriate antibiotic prescriptions (2, 3) , although the situation is now improving (4, 5) . bacterial antibiotic resistance is considered to be a major public health problem in the united states, and an interagency federal action plan has identified the decrease of unnecessary antibiotic prescriptions as critical to combating antimicrobial resistance (6) . in 1996, gates (7) estimated that the total annual cost of treating om with effusion in the united states was $5 billion, including both direct and indirect costs. this estimate included the cost of surgical placement of tympanostomy tubes (ventilation tubes placed in the tympanic membrane of the ear), a procedure that is commonly performed for the treatment of this disorder (8) . frequent om with effusion in early childhood may be associated with later speech and language problems, although causative relationships have not been definitively established (9, 10) . sinusitis also is a common and costly condition (11) ; in 1996, overall health care expenditures for sinusitis in the united states were estimated to be $5.8 billion, of which $1.8 billion was for children age 12 yr or younger. the primary treatment of sinusitis in children is medical management. adenoidectomy may be helpful (12) , although endoscopic sinus surgery is reserved for chronic, refractory cases (13, 14) . chronic sinusitis has a major negative impact on the quality of life of children whose disease is sufficiently severe to require endoscopic sinus surgery (15). viral illnesses usually are brief and self-limited conditions. however, viral infections produce inflammation, enhance nasopharyngeal bacterial colonization and adherence, alter the host's immune defenses, and are associated with bacterial complications, including acute om (16) , sinusitis, and pneumonia (17, 18) . acute om occurs in about 20% of children with viral upper respiratory infections (17) . although viral vaccines are in development, the use of vaccines to prevent upper respiratory tract infections is hampered by the large number of different viruses causing these infections (17) . the us advisory committee on immunization practices voted to recommend influenza vaccination for children ages 6 to 23 mo for the coming influenza season of 2004 to 2005; the impact of this recommendation remains to be seen (19) . despite the fact that streptococcus pneumoniae is the most common cause of bacterial acute om, the heptavalent pneumococcal polysaccharide conjugate vaccine only produced a 6% reduction in the overall number of episodes of acute om from any cause (20) . of inflammatory eicosanoids (29) . the level of ω-3 fatty acids and other pufas is largely determined by diet, unlike proteins, whose structure is genetically determined (26, 30) . changes in dietary habits in the united states in the last 20 to 30 yr have markedly increased the amount of ω-6 efa consumed (as in vegetable oils), whereas the amount of consumed ω-3 efa (as in cod liver oil and fish oil) has decreased (26, 31, 32) . the optimal ratio of ω-6/ω-3 efa in the diet is 3 to 4:1; in the united states, it is currently 10 to 20:1. this abnormal ratio has been linked with numerous disease states, especially those associated with inflammation. ω-3 fatty acid levels can be increased by eating more fatty fish and by consuming nutritional supplements such as cod liver oil, algalderived long-chain fatty acids, or fish oils (26, 31, 32) . free radical-induced lipid peroxidation may play a role in the acute (33) (34) (35) and chronic inflammation (36) of a guinea pig model of acute, unilateral om caused by infection with s. pneumoniae. inflammatory mediators have been demonstrated in both experimental and human middle ear effusions; these mediators include leukotrienes and prostaglandins, which are metabolites of aa and are derived from phospholipids in cell membranes. treatment with specific inhibitors of these mediators has prevented the development of om in some animal models of om (37) . free radicals are significant components of the inflammatory response, which is part of the pathophysiology of pneumococcal infections (38) and the influenza a virus (39) ; the latter are important causes of om. reactive oxygen species (ros) (40) have also been implicated in sinusitis. the association between respiratory virus infections and acute om in children is well-established (41, 42) . oral supplementation with efas (43) and zinc (44) has been shown to decrease the incidence of respiratory infections in children. trace elements (including zinc and se) have been shown to have important effects on the regulation of immune responses (45) . supplementation with ω-3 fatty acids has been reported to be beneficial in preventing infection in surgical patients (46) . the importance of ω-3 fatty acids and trace metals (including zinc and se) is already recognized in the relatively new field of "immunonutrition" (47) (48) (49) . the clinical efficacy of antioxidants in the treatment of om has been reported by two groups of russian investigators (50, 51) . of interest is the work of ginsburg (52) , who proposed that the main cause of tissue damage in infectious and inflammatory conditions is synergistic interactions among ros, microbial hemolysins, enzymes, and cytokines. antibiotics may have anti-inflammatory actions in additional to their antibacterial effects (53, 54) . macrolide antibiotics, effective in the treatment of adults with chronic rhinosinusitis (55) , have anti-inflammatory properties that contribute to this effect. however, the overuse of antibiotics is associated with the development of bacterial antibiotic resistance. in finland, the prevalence of macrolide-resistant group a streptococci diminished after the heavy use of macrolide antibiotics decreased (56) . in this age of antibiotic resistance, it is preferable to use antibiotics for their antibacterial effects rather than as anti-inflammatory agents. in our first study (57) , we obtained blood samples from 44 children undergoing clinically indicated ambulatory surgery at the new york eye & ear infirmary (nyee). there were 39 subjects in the tympanostomy tube group (tt); these children were undergoing placement of tympanostomy tubes for frequent ear infections and/or persistent middle ear effusion, with or without concomitant adenoidectomy and/or tonsillectomy. their mean (± standard deviation [sd]) age was 3.8 ± 1.8 yr; 72% were male; approximately half were hispanic and half were white; approximately half were private patients; and almost half were taking vitamin supplements. the comparison group (comp) was composed of children undergoing eye-muscle surgery as well as those undergoing ear, nose, and throat procedures such as bronchoscopy or laryngoscopy that did not involve the ears, adenoids, or tonsils. these subjects were slightly older, with a mean age of 5.7 ± 1.8 yr, and there was a lower percentage (20%) of private patients. no demographical information was available for the six adults in the adult control group (ac), supplied by ann moser of the peroxisomal disease section of the kennedy krieger institute genetics laboratory (baltimore, maryland). data regarding red blood cell (rbc) fatty acids, trace metals, and vitamin a were available for subsets of these subjects. the rbc fatty acid data are summarized in table 1 . the mean values for epa were lower in both groups of nyee children than in the acs supplied by kennedy krieger. the mean rbc epa values were: (a) tt = 0.31% ± 0.02% (standard error [se]), (n = 16); (b) comp = 0.31% ± 0.04% (se), (n = 5); and (c) ac = 0.48% ± 0.4% (se), (n = 6). these differences were statistically significant when analyzed by both parametric (anova, p < 0.002; f[2,24] = 8.336) and nonparametric (kruskal-wallis anova by ranks, p = 0.007; h[2, n = 27] = 9.924) tests. no other significant differences in rbc fatty acids were noted among the three groups, although additional differences might become apparent with larger sample sizes. in 1986, japanese investigators reported lower plasma levels of ω-3 fatty acids in young normal and atopic children than in adults (58) . they ascribed these findings to dietary changes in japan in the 30 yr prior to the study. data for plasma se, zinc, and copper for the children in the tt group are summarized in table 2 ; data from the published literature for children (59) and adults (25) for these parameters is also included, as are international system units. there was no statistically significant difference between the mean plasma se for study subjects (tt = 110 ng/ml ± 16.3 sd; n = 39) and the published values for children. both groups of children had lower se levels than published values for adults (p < 0.005, anova; f = 20.442; f[0.005] 3140 = 4.47) (60). statistical analyses were performed only for se because only the variances for se were homogeneous (bartlett's test for homogeneity of variances (60). the mean plasma vitamin a (retinol) level for the tt group was 39.1 μg/dl ± 10.8 (sd); (range: 23.6-72.1 μg/dl; n = 39). (multiply conventional units by 0.0349 to convert to international units [61] ). ballew (62) defined an inadequate vitamin a level as less than 20 μg/dl and a suboptimal vitamin a level as less than 30 μg/dl. the upper limit of the pediatric reference range for vitamin a is 80 μg/dl (61) . therefore, overall, the values for our subjects were within the reference range. russell (63) stated that a vitamin a level of 40 μg/dl predicted normal dark adaptation 95% of the time; 69% (27/39) of our subjects had vitamin a levels less than or equal to 40 μg/dl, although parents denied symptoms of night blindness for all children. our finding is consistent with ballew's (62) report that the 75th percentile for serum retinol levels in children ages 4 to 8 yr was 39.0 μg/dl. in addition, 15% (6/39) of our sample had suboptimal levels (<30 μg/dl), although none were inadequate (62) . in this suboptimal group, five of six children were not taking vitamin supplements, five of six children were hispanic, five of six children were general service patients, and four of six children were female (all of whom were hispanic). the overrepresentation of hispanic children in the subgroup of children with suboptimal vitamin a levels was also consistent with previous reports (62) . on a group basis, there was no statistically significant difference in the mean vitamin a levels between the subgroup of children whose families reported that they were taking vitamin supplements (39.7 μg/dl ± 11.6 sd; n = 17) and the subgroup of children whose families reported that they were not taking vitamin supplements (38.7 μg/dl ± 10.4 sd; n = 22). our subjects took a variety of prescription and over-the-counter vitamin preparations; no children were receiving or had taken cod liver oil; only one child in the fatty acid subgroup had a history of fish oil ingestion. of the eight different children's vitamin preparations examined, all contained vitamin a palmitate, vitamin a acetate, and/or β-carotene. the blood-level data (57) revealed that (a) study children had lower levels of rbc epa than adult controls; (b) 69% of study children had plasma vitamin a (retinol) levels in the lower reference range, with 15% in the suboptimal range; and (c) study subjects, like other children, had lower levels of plasma se than adults. therefore, for our clinical studies, we chose cod liver oil as a source of both vitamin a and epa and used it in conjunction with a marketed children's chewable multivitamin/mineral preparation containing se. we specifically chose cod liver oil as a source of vitamin a on the basis of our blood-level data, which revealed no significant difference in the vitamin a levels between the subgroups of children who were taking vitamin supplements and those who were not. although we could have used fish oil as the source of epa, fish oil does not contain vitamin a or d. the detailed contents of these supplements are shown in table 3 . the vitamin a content of cod liver oil used in our initial pilot study on om was 2000 to 2500 iu/teaspoon (5 ml); in the subsequent two studies, the vitamin a content was decreased to 1000 to 1250 iu/5 ml. to explore the clinical utility of these supplements, we then performed an open-label secondary prevention study, in which each child served as his or her own control (64) . we studied one om season, from september 1, 2000 to march 31, 2001 (57) . all children were patients of the soho pediatrics group, a private group practice in lower manhattan, new york. children were required to have had at least one episode of om from september 1 to november 30, 2000 (the early portion of om season under consideration). children with a known allergy to fish were excluded. eight children were enrolled, ranging in age from 0.8 to 4.4 yr; seven were caucasian, half were female, and all families were english-speaking. after enrollment, subjects received 1 teaspoon of lemon-flavored norwegian cod liver oil and one-half of a tablet of carlson's scooter rabbit chewable multivitamin-mineral (mvm) tablet per day (see table 3 ). mothers were instructed to crush the mvm tablet, measure the cod liver oil, and mix both in a small amount of food (such as applesauce, yogurt, or rice cereal) to administer the supplements to their children. parents were informed verbally and in writing that supplements were to be given only in the amounts required by the study and that study supplements were to be kept out of reach of children. of the eight children who entered the study, one could not tolerate the taste of cod liver oil. the remaining seven children received antibiotics for om for 12.3 ± 13.4 (p < 0.05; mean ± sd) fewer days during supplementation than before supplementation during the om season under study (see fig. 1 ). five of seven subjects had no additional episodes of om during supplementation, although it had no apparent effect on established serous middle ear effusions in two children. however, because our study lacked a randomized, parallel control group, we could not exclude the possibility that the decreased antibiotic usage we found might have occurred without the use of study supplements. based on our prior research (discussed in ref. 57 ) and the historical studies on cod liver oil and upper respiratory illnesses (65), we hypothesized that use of the study supplements by young children would decrease their doctor visits for upper respiratory illnesses during the late fall, winter, and early spring. we studied the effect of daily use of these supplements on the number of pediatric visits by young, inner-city, latino children from late autumn 2002 to early spring 2003 (83). we did not have a matched placebo for liquid cod liver oil. although adults and older children can swallow capsules, infants and toddlers cannot. furthermore, if capsules were cut open to administer the contents, the distinctive odor and taste of cod liver oil would immediately become apparent (57) . the absence of a matching placebo for liquid cod liver oil precluded our performing a classical double-blind, placebo-controlled study. lack of a placebo coupled with the fact that cod liver oil can be purchased without a prescription by interested parties (57, 66) led us to choose a study design in which we randomized pediatric sites, rather than individual patients. this type of design has been used in the worldwide studies of vitamin a supplementation, which are discussed in subheading section 5.3, that have included randomization by ward, household, village, or district (67) . it was also used in a food-consumption study to avoid changes in food habits resulting from knowledge of the other treatment (68) . randomized site design is commonly used in behavioral and educational studies where no placebo is possible (69) (70) (71) (72) ; a recent study of herd immunity and the pediatric heptavalent pneumococcal vaccine also used a randomized site design (73) . to minimize the influence of the study on the behavior of the participating families (69), we used a "no-contact" control group (74, 75) , which has also been used in behavioral and educational studies. the study was performed at pediatrics 2000, a multisite, private, pediatric group practice in new york city. two of the offices with similar demographics (low-income latino families), located 1.1 miles apart in upper manhattan, were randomized to a supplementation site and a medical records control site. study participants were children ages 6 mo to 5 yr of either gender and any race, religion, or nationality who were patients enrolled at the two offices where the study was being performed. study participants were required to be in new york city from enrollment through april 2003 (with the exception of brief vacations), and to have some type of medical insurance. patients who routinely received additional health care at other practices or medical centers were excluded; children with known fish allergy, a chronic, life-threatening condition (such as hiv/aids or cancer), feeding disorders, and epilepsy were also excluded. study materials were available in both english and spanish. per practice routine, two professional coders reviewed all charts from both sites, coded the visits, and entered the data into a computer with ndc medisoft™ network professional 7.02 software (76) . participants in the medical records control group were enrolled from october 21 to november 10, 2002; those in the supplementation group were enrolled from november 11 to december 12, 2002. we were unable to randomize enrollment at the two sites because the lemon-flavored cod liver oil used in the study (which was manufactured in norway) had been reformulated with less vitamin a (77) and was delayed in the us customs office. the study follow-up/supplementation period ended on may 1, 2003. a total of 94 children (47 at each site) were enrolled in the study. the mean age of the supplementation group was 2.03 yr (±1.04 sd), and the mean age of the control group was 2.08 yr (±1.10 sd). there were no statistically significant differences in the demographical characteristics of the study participants in the two groups: most were latino children from low-income families (as indicated by health insurance), and their mothers were predominantly unmarried immigrants from the dominican republic whose first language was spanish. children of at least 1 yr of age received 1 teaspoon of carlson's lemon-flavored cod liver oil per day and one-half tablet of carlson's scooter rabbit chewable mvm, the same doses used in our previous research administered in the same manner (57) . however, the vitamin a content of the cod liver oil was approximately half that used in our first pilot study of om (see table 3 ). thus, the full dose of supplements provided a total of 3750 iu of vitamin a and 700 iu of vitamin d per day. however, in the current study, the starting dose of supplements was halved for children ages 6 mo to 1 yr .visits were classified as upper respiratory visits, other illness visits, or visits not analyzed on the basis of the icd-9 visit code (78) . the primary outcome measure was upper respiratory visits during the follow-up/supplementation period; other illness visits during the same time period were considered as secondary outcome measures. as shown in figs. 2 and 3 and table 4 , the supplementation group had a statistically significant decrease in the mean number of upper respiratory visits over the course of the follow-up/supplementation period (p = 0.042; r = 0.893; r 2 = 0.797; y = 0.602 −0.002x), whereas the medical records control group had no change in this parameter (p = 0.999; r = 0.0006; r 2 = 0.0000; y = 0.259 + 1.43 × 10 -6 x). there was no statistically significant change in the mean number of other illness visits for either study group during the same time period. although there was a significant difference in the pattern of decreasing upper respiratory visits over time in the supplementation group, there was no difference in the total number of visits made by the two groups. data were analyzed on an intention-to-treat basis. as reported by their parents, 70% of our subjects completed a 5-to 6-mo course of lemon-flavored cod liver oil. by comparison, only 47% of families reported compliance with antibiotic prophylaxis for om in a study of latino children who attended an otolaryngology clinic (79) . our favorable compliance rates may partly result from the fact that young children in the dominican republic are often given cod liver oil or similar supplements, although families rarely continue this practice after moving to the united states. inflammation and edema of the sinonasal mucosa are important in the pathophysiology of sinusitis. based on our previous research and the similarities between om and sinusitis (80), we hypothesized that these nutritional supplements would also be effective adjunctive therapy for the treatment of children with chronic and/or recurrent sinusitis. therefore, we performed a 4-mo, open-label, dose-titration study in which each patient served as his or her own control (64, 81) . study participants were private pediatric otolaryngology outpatients of jay n. dolitsky, md, who resided in the new york metropolitan area and had a clinical diagnosis of chronic and/or recurrent sinusitis as well as symptoms of at least 3 mo of duration that were refractory to treatment with antibiotics. subjects were between ages 2 and 18 yr, of either gender and any race, religion, or nationality. children with known allergy to fish; chronic, life-threatening condition (such as hiv/aids or cancer); feeding disorder; seizure disorder; known cystic fibrosis; aspirin-intolerant asthma; and family plans to move outside the metropolitan area during the course of the study were excluded. subjects were enrolled from late january to early march 2003 and received supplements for 4 mo from the time of enrollment. primary endpoints were the number of doctor visits for acute respiratory illnesses and the child's sinus symptoms, which were quantified using a pediatric sinusitis symptom questionnaire (82) . the starting dose of supplements in the current study was the same as in our previous research (57): 1 teaspoon (5 ml) of carlson's lemon-flavored cod liver oil and one-half of a tablet of carlson's scooter rabbit chewable multivitamin-mineral per day (providing a total of 3750 iu of vitamin a and 700 iu of vitamin d per day). the vitamin a content of the cod liver oil was lower than in our first pilot study of om (57) but was the same as that used in our study of latino children (83; see table 3 ). supplement doses could be doubled to an intermediate dose (providing 7500 iu of vitamin a and 1400 iu of vitamin d per day) within 2 to 3 wk . if higher doses were needed, cod liver oil was discontinued and fish oil was administered instead (fish oil does not contain vitamin a or d). the maximum dose of fish oil was 3 g/d, and the maximum dose of multivitamin-minerals was four half-tablets per day (providing 10,000 iu of vitamin a and 800 iu of vitamin d per day). the titrated doses of vitamins a and d were higher than those used in our previous study (57) but were well-below the lowest daily toxic doses of these vitamins (61) (19,860 iu/d for vitamin a and 2800 iu/d for vitamin d). the us food and drug administration (fda) considers fish oil at dosages up to 3 g per day as safe for adults and children (84) . our four subjects were caucasian males, ranging in age from 4.2 to 9.8 yr, with chronic/recurrent sinusitis for at least 3 yr prior to entry in the study. three subjects had a positive response; one subject dropped out for administrative reasons. the responders had decreased sinus symptoms, fewer episodes of acute sinusitis, and fewer doctor visits for acute illnesses at 4, 6, and 8 wk after beginning study supplements. their parents reported that they had begun to recover from upper respiratory illnesses without complications, which was unusual for these children, as was improvement in springtime; their improvement had previously been limited to the summer months or periods of home-schooling. our findings are consistent with prior work by other clinical investigators. in a study of upper respiratory tract infections in young children, wald and colleagues (85) noted that an inflamed respiratory mucosa may not completely recover between episodes of infection. parsons (86) hypothesized that inflammation and edema of the sinonasal mucosa was the primary event in sinusitis, with bacterial infection as a secondary phenomenon. chronic/recurrent sinusitis is a debilitating disorder that may require treatment with intravenous antibiotics and/or endoscopic surgery. use of these supplements as adjunctive therapy for children with chronic/recurrent sinusitis is an inexpensive, noninvasive intervention that clinicians can use for selected patients, pending the outcomes of definitive, large, well-controlled studies. in the 1930s, during the pre-antibiotic era, lipoid aspiration pneumonia was reported with cod liver oil, mineral oil, and egg yolk, which were used at that time to treat sick and debilitated infants (87) . in 1950, caffey (88) reported vitamin a toxicity in children who were mistakenly treated with high-dose, long-term vitamin a administered in highly concentrated fish liver oil preparations that were available at that time. however, none of caffey's patients had received cod liver oil, and the highly concentrated fish liver oil preparations they received are no longer available in the united states. in our clinical studies, parents were instructed to crush the half-tablet of mvm, measure the cod liver oil, and mix both with a small amount of food (such as applesauce, yogurt, or rice cereal) before administering the supplements to their child. additionally, parents were informed both verbally and in writing that supplements were to be given only in the amounts required by the study and that study supplements were to be kept out of reach of children. the principal investigator spoke spanish, and all parental study materials were available in both spanish and english. to date, we have not encountered problems with aspiration or overdose in our studies. there is a clear association between viral respiratory infections and acute exacerbations of asthma in both children and adults (17) . there is also a link between sinusitis and asthma (89, 90) , with rhinovirus infections linked to both sinusitis and exacerbations of asthma (90) . additionally, latino children have a high incidence of asthma (91) . in view of the results of our studies (57, 81, 83) , we believe that these supplements could be clinically useful for young children (particularly latino children) with asthma, and we are currently beginning to organize research in this area. similarly to other countries worldwide (92) , socioeconomically disadvantaged children in the united states are at risk for micronutrient deficiencies (57, 62, 93) . although the supplements used in our research can be purchased in the united states without a prescription, their cost may pose an excessive financial burden to lowincome families. cod liver oil does not have a national drug code number, it is not available through medicaid in new york, and the children's vitamins we have located that are available through this system do not contain se or other trace metals. additionally, cod liver oil is not available through the united states department of agriculture (usda) special supplemental nutrition program for women, infants and children (wic); our request for such availability can be found online at http://www.fns.usda.gov/wic/anprmcomments/ ihp-06.pdf. furthermore, purchase of vitamins with us food stamps is not permitted (see http://www.fns.usda.gov/fsp/faqs.htm#9). if our results are confirmed in larger studies, a system change will be required to provide these supplements to nutritionally vulnerable, socioeconomically disadvantaged children living in the united states. egyptian and greek physicians may have understood the value of liver (high in vitamin a) for the treatment of night blindness, an early ocular manifestation of vitamin a deficiency (94, 95) . the use of fish oils in medicine was mentioned by hippocrates, and pliny discussed the use of dophin liver oil for the treatment of chronic skin eruptions (96) . however, these classical physicians did not appear to know about the use cod liver oil. the coastal fishermen of northern europe apparently used cod liver oil for many years for the treatment of aches and pains (96, 97) . however, the first recorded use of cod liver oil by physicians was from the manchester infirmary in england during the 1780s (96, 97) , where it was found to be very effective for "old pains" and "rheumatism," which were probably cases of osteomalacia (a bone disease of adults) (96) . the pattern of discovery was that the use of cod liver oil by fishing folk and peasants was accidentally observed by a physician, who then tried it and made it known to the medical profession (96) . guy (96) states that there was no further mention of cod liver oil in the english medical literature until its revival in 1841 by bennett, who had observed its use in germany. bennett reported that in holland, cod liver oil had obtained a wide reputation as a cure for rickets (a bone disease of children) "long before its remedial properties were acknowledged by physicians" (see ref. 97, p. 67) . in the 1820s, schenk and schuette published independent reports in the german literature regarding the value of cod liver oil for curing rickets (97) , and schuette reported that he used cod liver oil successfully for 25 yr. cod liver oil for the treatment of rickets was introduced in france by trousseau in the 1830s (97) . the demand for cod liver oil was so great that all types of substitutes were used, and reports of failure, contamination, and substitutes for cod liver oil began to appear in the literature before the middle of the 19th century. vitamin a was discovered as the result of a long, incremental process with contributions by numerous investigators (95, 98) . at the end of the 19th century and the beginning of the 20th century, nutritional theories were tested under well-controlled laboratory conditions through the administration of experimental diets to animals, and specific factors necessary for their growth and survival began to be identified. during this time, frederick hopkins, at cambridge university, proposed that there were "accessory factors" in foods that were necessary for life but that had not been previously identified; casimir funk named these factors "vital amines" or "vitamines" (65) . in 1913, in the same issue of the journal of biological chemistry, two groups independently reported the existence of a fat-soluble factor that was essential for the growth of rats (65, (99) (100) (101) . mccollum and davis of the university of wisconsin (99) demonstrated that after a certain age, the growth of rats was dependent on an ether extract from eggs or butter. using a different experimental diet, osborne and mendel (100) , of yale university, found that there was an "essential accessory factor" in butter needed for the normal growth of rats. this fat-soluble growth factor, originally termed "fat-soluble a," soon became known as "vitamine a" (65). the discovery of vitamin d was closely tied to work on the prevention and treatment of rickets. during the industrial revolution, rickets spread rapidly throughout europe, particularly among the urban poor, who lived in the sunless alleys of factory towns and urban slums (97) . in 1918, mellanby (102) , an english physician and professor of pharmacology, reported the first animal model of rickets, which he developed in puppies. in a simple, two-page report to the physiological society, he noted that the daily administration of foods such as butter, cod liver oil, or 500 cc of milk (among others) was effective in preventing rickets in his model, whereas casein and linseed oil were among the substances that were ineffective. mellanby felt that rickets was a deficiency disease and stated that "the anti-rachitic accessory factor has characters related to the growth accessory factor [vitamin a], although it is not identical with the latter …" (ref. 102, p. xi) . however, mellanby was not able to distinguish these two factors; this was accomplished by mccollum and his new collaborators at johns hopkins university. in the 1920s, mccollum and his colleagues developed a rat model of rickets that could also be cured with cod liver oil. they were then faced with the same question that perplexed mellanby: was the anti-rachitic factor vitamin a, or was it another substance with a similar distribution as fat-soluble vitamin a (103)? it was known that the vitamin a-deficient animals in these studies often developed ocular abnormalities, including dryness of the eyes, corneal ulceration, and blindness, similar to xeropthalmia in humans (65) . additionally, hopkins demonstrated that oxidation destroyed fat-soluble a (103) . using these facts, in 1922, mccollum and his colleagues (104) reported that when cod liver oil was oxidized for 12 or 20 h, it could no longer cure xerophthalmia, although it could prevent rickets. therefore, they concluded that the anti-xerophthalmic and the anti-rachitic properties were a result of two distinct substances, and that the antirachitic factor, which specifically regulated bone metabolism, was the more heat-stable factor. because this was the fourth vitamin to be discovered, mccollum's group named it vitamin d in 1925 (97) . the fact that both exposure to sunlight and cod liver oil could prevent or cure rickets was perplexing and controversial (105) . careful experiments by chick and coworkers (103) , working in vienna from 1919 to 1922, confirmed the value of both cod liver oil and sunlight in the prevention and treatment of rickets in young infants. in 1919, huldschinsky (97), a pediatrician in berlin, used light from a mercuryvapor quartz lamp (which includes ultraviolet [uv] wavelengths) to cure four cases of advanced rickets in children with up to 2 mo of treatment. when huldschinsky exposed one arm of a rachitic child to the uv irradiation, he found that the rickets in the child's other arm was cured to the same degree as in the exposed arm. therefore, he concluded that phototherapy was not a local effect and speculated that as a result of exposure to uv light, something was formed in the skin that was then carried to other sites, where it had its anti-rachitic effect (105) . in 1925, hess and weinstock (97) reached similar conclusions based on experimental work in animals. these theories were confirmed in 1936, when windaus, working in germany, demonstrated that skin contains the natural prehormone of vitamin d, which is converted to vitamin d 3 when the skin is exposed to uv irradiation (including light from a mercury-vapor lamp) (97). historical investigators were well-aware of an association between rickets and respiratory diseases. in their 1917 paper on rickets, hess and unger stated that "rickets is a predisposing cause of these respiratory diseases (pulmonary tuberculosis, pneumonia, and whooping cough)" (ref. 106, p. 1583 ). in her 1927 paper on community control of rickets, eliot stated that "susceptibility to upper respiratory infections, such as colds, bronchitis and pneumonia, is greatly increased in infancy and early childhood by rickets" (ref. 107, p. 114 ). based on prior animal studies and clinical work by german investigators, ellison discounted the contribution of vitamin d in the efficacy of cod liver oil for measles. nonetheless, he acknowledged that "it is possible that some adjuvant effect was obtained from the co-operation of the two factors [vitamins a and d]" (ref. 108, p. 710 ). in a 1936 study of vitamins a and d (individually or combined) for children hospitalized with measles, mackay noted "there is much to indicate that resistance to infections is reduced in children suffering form an overt deficiency of either of these vitamins [vitamin a or d]" (ref. 109, p. 127 ). semba noted that cod liver oil, a rich source of vitamins a and d, was used as a treatment for tuberculosis for more than 100 yr (110) . in the 1840s, charlotte brontë, the author of jane eyre, suffered from tuberculosis, and her treatment included cod liver oil (111) . a 1917 textbook on tuberculosis, although recognizing that there was no specific treatment for tuberculosis at that time, stated that "one of the oldest and best established remedies for the treatment of tuberculosis is cod liver oil" (ref. 112, p. 467); however, the mechanism of action of cod liver oil was unknown. the situation had changed little by 1946, when goldberg's textbook stated that cod liver oil "has been used empirically for many centuries in the treatment of pulmonary tuberculosis without any definite knowledge of its action" (ref. 113 , p. c-81). however, the use of cod liver oil for tuberculosis faded as specific treatments were developed, and "cod liver oil" is not listed in the index of a modern textbook on tuberculosis (114). mellanby (see section 4.3.) had a large colony of dogs that were maintained on experimental diets. in 1926, mellanby reported, "at one period in the course of my experimental investigations on dogs, the work was greatly hampered by the development of an inflammatory condition of the lungs" (ref. 115, p. 518), which was bronchopneumonia. on postmortem examination, the pneumonia was largely restricted to the vitamin adeficient dogs, and he speculated that this might be relevant to respiratory illness in children (65, 115) . in 1928, green and mellanby reported that a deficiency of vitamin a, but not vitamin d, caused increased infections in a rat model, leading them to call vitamin a an "anti-infective" agent; they speculated that this was related to the epithelial changes caused by vitamin a deficiency (116) . in 1932, ellison (65, 108) reported the results of a study of concentrated cod liver oil for children who were hospitalized with measles. ellison was aware of mellanby's work on the anti-infective properties of vitamin a and also knew that vitamin a deficiency damaged epithelial cells in the respiratory tract (117, 118) . ellison specifically chose to study measles because it was "a disease which attacks epithelial defences and whose incidence is greatest in those members of the community who are most likely to be suffering from various grades of vitamin deficiency…the children of the poorest classes" (ref. 108, p. 709). he studied 600 children under age 5 yr who were admitted to the grove hospital (london) with measles. the cases were randomized by ward to treatment with a highly concentrated cod liver oil preparation or a control treatment of standard treatment (no placebo was used). treatment with cod liver oil reduced measles mortality by approximately one-half, from 8.7% in the control group to 3.7% in the treated group (65, 108) . based on animal studies and german clinical work, ellison attributed the efficacy of cod liver oil to vitamin a, although he did concede that some adjuvant effect could have been obtained from the cooperation of the two factors (108) . a subsequent study published in 1936 (65, 109) reported that neither vitamins a and d together nor vitamin d alone had an effect on reducing the mortality rate from measles. however, the control mortality rate in this later study decreased to 2.6%, making it difficult to demonstrate an improvement. by 1940, numerous studies had been conducted to evaluate the ability of vitamin a (usually given as cod liver oil) to decrease the incidence of respiratory infections. the results were mixed, with about half showing a positive impact and the rest demonstrating no effect (65) . however, cod liver oil did have a significant impact on decreasing industrial absenteeism (65) . in a 1935 study of cod liver oil for the prevention of the common cold in school children, the investigator was not able maintain a control group given no supplements because enthusiastic families purchased cod liver oil for their children outside of the study (65, 66) ; this finding is relevant to our current work. with the introduction of sulfa antibiotics and penicillin in the 1930s to 1940s (65), as well as the improvements in diet in industrialized countries in the late 1930s, interest in anti-infective therapy shifted to antibiotics and away from vitamin a (98). in the mid-1920s, uv radiation of food and a variety of other substances was demonstrated to produce anti-rachitic properties (105) . steenbock patented the addition of provitamin d to foods followed by uv irradiation to produce anti-rachitic activity. in the 1930s, the addition of provitamin d 2 to milk followed by uv irradiation was widely practiced in the united states and europe. rickets was eradicated as a significant public health problem in the countries that used this vitamin d fortification process (105) . in the late 1940s, otto isler and his collaborators in basel reported the synthesis of all-trans-vitamin a from the inexpensive precursor β-ionone (95) . in the same time period, arens and van dorp (94) reported the synthesis of retinoic acid. within a few years, the price of vitamin a fell 10-fold, and it became economically feasible to add vitamin a more generally to foods. during the latter part of the 19th century, cod liver oil was rarely used in america, although the reason for this lack of use is not clear (96, 97) . however, there was a resurgence in interest, and in 1917, hess and unger wrote, "for many years cod liver oil has been regarded as the sovereign remedy for rickets" (ref. 106, p. 1583) . they successfully prevented rickets with cod liver oil in susceptible african-american babies in a lowincome neighborhood in new york city (106, 119) . hess urged officials to dispense cod liver oil at the baby health stations at cost, but they declined because it would be too expensive, and they thought that additional milk would be preferable to cod liver oil (106) . cod liver oil and sunlight were highly valued for the prevention of rickets, and nurses taught mothers of infants how to use these remedies for their infants (107) . from the 1920s to the 1940s, many children in the united states were given cod liver oil each day (26, 65) with orange juice (which was know to prevent scurvy). however, older preparations of cod liver oil had an unpleasant taste, the quality of different preparations was erratic (119) , and medical professionals became concerned about lipoid aspiration pneumonia (87) and vitamin a toxicity (88) . by the 1950s, cod liver oil had been largely replaced by synthetic vitamins in the united states; however, the latter do not contain ω-3 fatty acids, which have anti-inflammatory properties (26) and important effects on immune function (47, 120) . in norway, the norwegian nutrition council continues to recommend supplementation with cod liver oil beginning at age 4 wk, because it provides ω-3 fatty acids in addition to vitamin d (121). before columbus made his first voyage to america, basque fisherman were secretly fishing the massive stocks of cod and other groundfish off the new england coast (122, 123) . their salt cod was a staple in mediterranean markets, and cod was a staple of the european diet for more than 400 yr (122) . although fishermen exploited cod for centuries, the technological innovations of the 20th century led to the collapse of cod stocks in north america. motorized boats dragged the ocean floor with massive trawl nets, destroying both cod fish and their habitat. factory ships with refrigeration have almost erased the limit to the amount of cod that can be caught and sold internationally without spoiling (123) ; increasingly powerful and accurate sonar produces detailed readouts of nooks where schools of fish may lurk; and shipping fleets can position themselves precisely through use of the satellites of the global positioning system (124) . despite growing regulations on allowable catches and fishing equipment, cod stocks have continued to decrease across the north atlantic. in 1992, the canadian government declared a temporary moratorium on cod fishing; the moratorium was extended in 1994. in 2003, with cod stocks showing no sign of recovery, the canadian government banned all cod fishing off its eastern provinces and identified some cod populations as endangered. the us government also imposed restrictions on cod fishing (123) . however, it is unclear whether north atlantic cod stocks will recover. the level of polychlorinated biphenyls (pcbs) and dioxins in fish and fish oils has become a concern as oceans have become progressively contaminated with industrial waste. this issue was addressed in the united kingdom and europe by purity standards (125) , which were revised and made more strict in 2002 (126) . in the same year, the uk food standards agency reported that exposure to dioxins had decreased by 75% over the previous 20 yr and that the levels of dioxins and pcbs found in most of the samples in their most recent fish oil survey were lower than in previous surveys that were performed in 1994 and 1996 (126) . mercury contamination of fish is also a concern, and the fda advises that young children and women of childbearing age should avoid tilefish, swordfish, shark, and king mackerel because of their elevated levels of mercury (127) . however, an analysis of us fish oil supplements revealed no detectable mercury, with a limit of detection of 0.1 μg of mercury per gram (128). after a 40-yr hiatus, interest in the anti-infective properties of vitamin a was rekindled in the 1980s by the observation of increased mortality in indonesian children who had vitamin a deficiency and xerophthalmia (65, 129) . the first symptom of eye disease from vitamin a deficiency is night blindness; at this stage, bitot's spots (superficial, foamy gray, triangular spots) may be present on the conjunctiva (129, 130) . this is followed in later stages by xerophthalmia (dryness of the conjunctiva), keratomalacia (corneal ulceration), and blindness (77) . since the 1980s, numerous studies have been performed regarding the effect of vitamin a supplementation on the health of children in developing countries. for a complete review of this subject, the reader is referred to chapter 23, as well as reviews (110, 131, 132) , and meta-analyses (67, 133, 134) . for the purpose of this chapter, the findings are summarized to provide a basis of comparison to the status of vitamin a in the developed world as well as to provide a perspective on the results of our research. vitamin a supplementation of children in developing countries decreased overall childhood mortality by about 30% (67, 132) . community-based studies of vitamin a supplementation have indicated that it may decrease the severity, but not the incidence, of diarrhea (131) . in children hospitalized with measles in the developing world, vitamin a supplementation decreased mortality by an average of 60% (67, 132, 135) ; the decrease in mortality from measles-related pneumonia was particularly noteable (67) . the modern studies are consistent with the results of ellison's historical study of cod liver oil for children who are hospitalized with measles (see section 4.6.). the role of vitamin a supplementation in measles is also consistent with the fact that infectious diseases that induce the acute-phase response transiently depress serum retinol concentrations, that vitamin a deficiency impedes the normal regeneration of mucosal barriers damaged by infection, and that it also diminishes the immune function of white blood cells (136, 137) . however, several placebo-controlled trials have demonstrated that high-dose vitamin a supplementation is not effective in decreasing the severity of pneumonia in hospitalized children in developing countries and that large doses of vitamin a may be harmful when given to well-nourished children in these areas (132, 134) . additionally, vitamin a supplementation is not effective for children who are hospitalized with pneumonia caused by respiratory syncytial virus, which is a paramyxovirus similar to measles and an important cause of infantile bronchiolitis and pneumonia (138, 139) . in a multicenter study performed in the united states, patients who received vitamin a actually had longer hospital stays than those who received placebo (138) . infection with hiv has become increasingly prevalent in many developing countries. vitamin a supplementation of children younger than age 5 yr who are hiv-positive decreases aids-related deaths as well as total mortality and morbidity from diarrhea (140) . small, frequent doses of vitamin a may be more protective than large, periodic doses. additionally, adequate dietary vitamin a intake is associated with a significant decrease in mortality (141) , diarrheal and respiratory infections (142) , and stunting (143) . new strategies in vitamin a supplementation in developing countries include targeting at-risk populations, improving dietary sources of vitamin a, using horticultural approaches, fortifying food, and addressing multinutrient deficiencies (140). modern studies of vitamin d indicate that calcitriol (1,25 dihydroxyvitamin d), the active form of vitamin d, has important nonclassical effects beyond the regulation of calcium metabolism. these include the modulation of hormone and cytokine production and secretion as well as the regulation of proliferation and differentiation (144) . calcitriol, a potent inhibitor of human t-lymphocyte proliferation (145, 146) , and vitamin d analogs have been shown to be effective in the prevention and treatment of some models of autoimmune disease in rodents-particularly autoimmune diabetes in mice (144, 147, 148) . in 1997, muhe and colleagues (110, 149) reported the importance of nutritional rickets in the development of pneumonia in developing countries. this is consistent with the work of historical authors discussed earlier, who were also aware of this association. vitamin a deficiency that is severe enough to cause blindness is uncommon in the developed world (62) . however, some segments of the us population, particularly socioeconomically disadvantaged children (93) as well as african-and mexican-american children (62), may have suboptimal levels of vitamin a. in 1932, ellison recognized that children from lowincome households were the most likely to have vitamin deficiencies (see section 4.6.) (108) . consistent with these reports, in our original study, five of six children with suboptimal levels of vitamin a were hispanic general-service patients (57) . additionally, young children in the united states-particularly those in the toddler and preschool age groups-may not have adequate dietary intakes of vitamin a (150) . in developed countries, high intakes of vitamin a (but not β-carotene) by pregnant women have been associated with teratogenesis (151), leading to recommendations that prenatal vitamins should contain no more than 8000 iu of preformed vitamin a (152) . additionally, high intakes of vitamin a by postmenopausal women in the united states (153) and 49-to 51-yr-old men in sweden (154) have been associated with a higher risk of hip fractures. as a result, vitamin a supplementation and fortification of food with vitamin a in western countries has been questioned (77) . as discussed under section 3.3., the amount of vitamin a in norwegian cod liver oil has been reduced. nonetheless, the norwegian nutrition council continues to recommend supplementation with cod liver oil beginning at age 4 wk, because it provides ω-3 fatty acids in addition to vitamin d (121). numerous investigators have stated that vitamin a deficiency rarely exists alone and that it is usually accompanied by variety of other nutritional deficiencies (92, 131, 132, 134, (155) (156) (157) (158) . in a 1986 review, mejía (92) noted that vitamin a deficiency primarily affects the world's most underprivileged populations, which, because of their limited socioeconomic condition, also lack a variety of other essential nutrients. he emphasized the importance of the interaction between nutrients and reviewed the established relationships of vitamin a status to protein, dietary fat, vitamin e, zinc, and iron (92) . mejía also mentioned the more controversial links of vitamin a to iodine metabolism; vitamins c, k, and d; calcium, and copper. realizing that the relationships might be direct or indirect, he emphasized the importance of considering these interactions when "treating or preventing vitamin a deficiency both at the clinical and at the population levels" (ref. 92, p. 95) . olson (155) reported that deficiencies of various other nutrients, including protein, α-tocopherol (vitamin e), iron, and zinc, adversely affects the transportation, storage, and utilization of vitamin a. he also noted that the absorption of vitamin a and carotenoids is markedly reduced when diets contain very little fat (<5 g/d). more recently, villamor and fawzi (132) stated that supplementation with vitamins and minerals in addition to vitamin a is likely to "reduce the burden of adverse health outcomes," because of the physiological interactions between nutrients and overlapping micronutrient deficiencies, including iron and zinc. semba (98) noted that antenatal supplementation with multivitamins reduced fetal deaths and low birthweight in pregnant women who were infected with hiv, but vitamin a alone had no significant effect. semba (110) also discussed the role that other deficiencies of vitamin d (149) and zinc (159) may have in susceptibility to respiratory infections. we agree with semba, who stated that "further studies are needed to address the use of vitamin a in multi-micronutrient supplements, as there is increasing evidence that other coexisting micronutrient deficiencies may limit the efficacy of vitamin a" (ref. 131, p. 105). our work is consistent with the historical uses of cod liver oil, vitamin a as the "antiinfective" vitamin, the link between rickets and respiratory tract infections, the modern understanding of immunomodulatory effects of vitamin d, the importance of ω-3 fatty acids and trace metals in decreasing inflammation, the clinical observation that inflamed respiratory mucosa may not completely recover between episodes of infection, and the current concept of the importance of multiple micronutrient deficiencies. we have demonstrated that use of flavored cod liver oil (which meets european purity standards) and a chewable children's multivitamin-mineral with trace metals, including se, can decrease morbidity from upper respiratory tract illnesses, om, and sinusitis in young children living in the united states. these supplements were particularly wellaccepted by latino families from the caribbean, where use of cod liver oil is a cultural tradition. currently, there is adequate information for practitioners to recommend the use of these supplements, when indicated, to their individual patients; information for practitioners and families is available online at http://www.drlinday.com. the supplements can be purchased in the united states without a prescription. further research is needed to evaluate the effect of the supplements on antibiotic prescription for these illnesses and to explore their role as adjunctive therapy in asthma. additionally, our findings need to be confirmed in larger studies to facilitate large-scale, policy decision making. use of these supplements has the potential to improve children's health and decrease the cost of their health care. however, cod liver oil does not have a national drug code number and is not available through medicaid in new york, and the children's vitamins we have located that are available through this system do not contain se or other trace metals. also, cod liver oil is not available through the usda wic program; our request for such availability can be found online at http://www.fns.usda.gov/wic/anprmcomments/ ihp-06.pdf. furthermore, purchase of vitamins with us food stamps is not permitted (see http://www.fns.usda.gov/fsp/faqs.htm#9). socioeconomically disadvantaged children living in the united states are at risk for micronutrient deficiencies. although the supplements used in our research can be purchased in the united states without a prescription, their cost may pose an excessive financial burden to low-income families. if our results are confirmed in larger studies, a system change will be needed to provide these supplements to nutritionally vulnerable, socioeconomically disadvantaged children living in the united states. this work was supported in part by the department of otolaryngology of the new york eye and ear infirmary (new york, ny). j. r. carlson laboratories, (arlington ambulatory health care visits by children: principal diagnosis and place of visit antibiotic prescribing for children with colds, upper respiratory tract infections, and bronchitis misconceptions about colds and predictors of health service utilization trends in antimicrobial prescribing rates for children and adolescents reduction in antibiotic use among us children interagency task force on antimicrobial resistance: a public health action plan to combat antimicrobial resistance. part 1: domestic issues cost-effectiveness considerations in otitis media treatment the role of adjuvant adenoidectomy and tonsillectomy in the outcome of the insertion of tympanostomy tubes otitis media in infants and children language, speech sound production, and cognition in three-year-old children in relation to otitis media in their first three years of life healthcare expenditures for sinusitis in 1996: contributions of asthma, rhinitis, and other airway disorders pilot study of outcomes in pediatric rhinosinusitis efficacy of a stepwise protocol that includes intravenous antibiotic therapy for the management of chronic sinusitis in children and adolescents sinusitis in children the health impact of chronic recurrent rhinosinusitis in children otitis media, atelectasis, and eustachian tube dysfunction the common cold viruses and acute otitis media incidence of outpatient visits and hospitalizations related to influenza in infants and young children efficacy of a pneumococcal conjugate vaccine against acute otitis media free radicals in biology and medicine mammalian selenoproteins se repletion and glutathione peroxidasedifferential effects on plasma and red blood cell enzyme activity free radical scavenging enzyme activity profiles in risk assessment of idiosyncratic drug reactions free radical scavenging enzyme activity and related trace metals in clozapine-induced agranulocytosis: a pilot study omega-3 fatty acids in health and disease and in growth and development nutrition and cognitive development functional effects of increasing omega-3 fatty acid intake dietary polyunsaturated fatty acids and inflammatory mediator production dna-protein and membrane-lipid: competing paradigms in biomedical research fats that heal, fats that kill the importance of the ratio of omega-6/omega-3 essential fatty acids lipoperoxidation as a measure of free radical injury in otitis media evidence of oxygen radical injury in experimental otitis media hydrogen peroxide in acute otitis media in guinea pigs effects of 21-aminosteroid u-74389g on acute otitis media in a guinea pig model arachidonic acid metabolites in experimental otitis media and effects of anti-inflammatory drugs pathogenesis of pneumococcal inflammation: otitis media inflammatory responses in influenza a virus infection malondialdehyde levels and superoxide dismutase activity in experimental maxillary sinusitis respiratory virus infection and otitis media detection of rhinovirus, respiratory syncytial virus, and coronavirus infections in acute otitis media by reverse transcriptase polymerase chain reaction essential fatty acids: the effects of dietary supplementation among children with recurrent respiratory infections zinc supplementation reduces the incidence of acute lower respiratory infections in infants and preschool children: a double-blind, controlled trial trace element regulation of immunity and infection early enteral administration of a formula (impact) supplemented with arginine, nucleotides, and fish oil in intensive care unit patients: results of a multicenter, prospective, randomized, clinical trial immunonutrition: the role of omega-3 fatty acids dietary lipids and immune function immunonutrition: the pediatric experience pathogenetic validation of optimal antioxidant therapy in suppurative inflammatory otic diseases in children efficacy of antioxidant therapy in patients with acute and chronic purulent otitis media could synergistic interactions among reactive oxygen species, proteinases, membraneperforating enzymes, hydrolases, microbial hemolysins and cytokines be the main cause of tissue damage in infectious and inflammatory conditions? reduction of endotoxin-induced inflammation of the middle ear by polymyxin b clarithromycin and prednisolone inhibit cytokine production in chronic rhinosinusitis the effect of changes in the consumption of macrolide antibiotics on erythromycin resistance in group a streptococci in finland. finnish study group for antimicrobial resistance lemon-flavored cod liver oil and a multivitamin-mineral supplement for the secondary prevention of otitis media in young children: pilot research fatty acid compositions of plasma lipids in young atopic patients racial differences in free radical scavenging enzyme activity in children biostatistical analysis pediatric nutrition handbook serum retinol distributions in residents of the united states: third national health and nutrition examination survey, 1988-1994 the vitamin a spectrum: from deficiency to toxicity single-case research designs vitamin a as "anti-infective" therapy, 1920-1940 a" as a prophylactic against the common "cold" in groups of school children vitamin a supplementation and child mortality. a meta-analysis lack of improvement in vitamin a status with increased consumption of dark-green leafy vegetables community intervention trial for smoking cessation (commit): summary of design and intervention. commit research group statistical design of the child and adolescent trial for cardiovascular health (catch): implications of cluster randomization abatement of cockroach allergen (bla g 1) in low-income, urban housing: a randomized controlled trial evaluation of aid to diagnosis of pigmented skin lesions in general practice: controlled trial randomised by practice efficacy and safety of seven-valent conjugate pneumococcal vaccine in american indian children: group randomised trial active: a cognitive intervention trial to promote independence in older adults effects of cognitive training interventions with older adults: a randomized controlled trial ndc medisoft™ network professional program. version 7.02. ndchealth physician services hypervitaminosis a and fractures american medical association international classification of diseases, 9th revision clinical modification compliance with prophylactic antibiotics for otitis media in a new york city clinic otitis media and sinusitis: similar diseases nutritional supplements as adjunctive therapy for children with chronic/recurrent sinusitis: pilot research the development and validation of an instrument to assess acute sinus disease in children effect of daily cod liver oil and a multivitamin-mineral with se on upper respiratory pediatric visits by young, inner-city, latino children: randomized pediatric sites department of health and human services, food and drug administration: substances affirmed as generally recognized as safe: menhaden oil upper respiratory tract infections in young children: duration of and frequency of complications chronic sinusitis: a medical or surgical disease? pneumonia due to the aspiration of lipoids chronic poisoning due to excess of vitamin a treatment of pediatric sinusitis viral respiratory infections in association with asthma and sinusitis: a review the health of latino children: urgent priorities, unanswered questions, and a research agenda vitamin a-nutrient interrelationships vitamin a and vitamin e statuses of preschool children of socioeconomically disadvantaged families living in the midwestern united states vitamin a and retinoids handbook of vitamins. second ed. new york: marcel dekker the history of cod liver oil as a remedy years of feeding infants in america preventive nutrition: the comprehensive guide for health professionals the necessity of certain lipins in the diet during growth the relation of growth to the chemical constitutents of the diet goodman & gilman's the pharmacological basis of therapeutics the part played by an "accessory factor" in the production of experimental rickets vitamin d, cod-liver oil, sunlight, and rickets: a historical perspective studies on experimental rickets. xxi: an experimental demonstration of the existence of a vitamin which promotes calcium deposition modern nutrition in health and disease. ninth ed. williams & wilkins prophylactic therapy for rickets in a negro community the new haven demonstration of community control of rickets intensive vitamin therapy in measles the therapeutic value of vitamins a & d in measles vitamin a and immunity to viral, bacterial and protozoan infections the white plague 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applications vitamin a supplementation: implications for morbidity and mortality in children vitamin a supplementation in infectious diseases: a meta-analysis vitamin a supplementation and childhood morbidity from diarrhea and respiratory infections: a meta-analysis a randomized, controlled trial of vitamin a in children with severe measles vitamin a and retinoids in antiviral responses vitamin a, infection, and immune function vitamin a therapy for children with respiratory syncytial virus infection: a multicenter trial in the united states treatment of respiratory syncytial virus infection with vitamin a: a randomized vitamin a supplements ameliorate the adverse effect of hiv-1, malaria, and diarrheal infections on child growth vitamin a supplements ameliorate the adverse effect of hiv-1, malaria, and diarrheal infections on child growth dietary vitamin a intake and the risk of mortality among children dietary vitamin a intake and the incidence of diarrhea and respiratory infection among sudanese children dietary vitamin a intake in relation to child growth vitamin d analogues in insulin-dependent diabetes mellitus and other autoimmune diseases: a therapeutic perspective comparison of the effects of 1,25-dihydroxyvitamin d3 on t lymphocyte subpopulations the immunobiology of vitamin d 1,25-dihydroxyvitamin d3 prevents insulitis in nod mice prevention of autoimmune diabetes in nod mice by 1,25 dihydroxyvitamin d3 case-control study of the role of nutritional rickets in the risk of developing pneumonia in ethiopian children subclinical vitamin a deficiency: a potentially unrecognized problem in the united states teratogenicity of high vitamin a intake continuing caution is needed vitamin a intake and hip fractures among postmenopausal women serum retinol levels and the risk of fracture recommended dietary intakes (rdi) of vitamin a in humans nutrition and development: other micronutrients' effect on growth and cognition iron and zinc supplementation improves indicators of vitamin a status of mexican preschoolers impact of zinc supplementation on morbidity from diarrhea and respiratory infections among rural guatemalan children heights, il) donated the nutritional supplements used in this research but had no other role in the design or conduct of the study. information for practitioners and families regarding this research is available at http://www.drlinday.com. key: cord-254646-psolkrom authors: matsui, mary s. title: vitamin d update date: 2020-10-14 journal: curr dermatol rep doi: 10.1007/s13671-020-00315-0 sha: doc_id: 254646 cord_uid: psolkrom purpose: the goal of this review is to provide an update in the field of vitamin d, in particular, the role of vitamin d in non-skeletal health, the complexity of providing patient guidance regarding obtaining sufficient vitamin d, and the possible involvement of vitamin d in morbidity and mortality due to sars-cov-2 (covid-19). recent findings: in addition to bone health, vitamin d may play a role in innate immunity, cardiovascular disease, and asthma. although rickets is often regarded as an historical disease of the early twentieth century, it appears to be making a comeback worldwide, including “first-world” countries. broad-spectrum sunscreens (with high uva filters) that prevent erythema are unlikely to compromise vitamin d status in healthy populations. summary: new attention is now focused on the role of vitamin d in a variety of diseases, and more individualized patient recommendation schemes are being considered that take into account more realistic and achievable goals for achieving sufficient vitamin d through diet, supplements, and sun behavior. in the last 10 years, over 41,000 peer-reviewed research studies have been published on vitamin d, and since its original discovery as a sunlight-generated factor important to bone health, a more complex story of vitamin d has continued to evolve. vitamin d, technically not a vitamin, has been linked not just to rickets in children and osteomalacia in adults, but also has been suggested to play a role in diabetes, celiac disease, asthma, atopic dermatitis, tuberculosis, and, most recently, covid-19. this review will briefly summarize fundamental, well-established aspects of vitamin d and human health and then will also discuss (a) some of the most recent work related to vitamin d and non-skeletal-associated health issues; (b) the complexity of establishing meaningful vitamin d measurement metrics and assessing vitamin d status; c)decisionmaking for obtaining vitamin d through diet, supplements, or sun exposure; (d) the impact of skin type, pigmentation, and sunscreen on vitamin d levels; and (e) evidence for a potential influence of vitamin d on the mortality and morbidity of covid-19 through modulation of the pro-inflammatory cytokine response and respiratory response to the virus. some would urge us to move away from the nomenclature of vitamin d as a vitamin and, instead, acknowledge that vitamin d3 is a prohormone produced in skin through ultraviolet irradiation of 7-dehydrocholesterol (7dhc or provitamin d3) [1•] . this previtamin d3 is biologically inert and must undergo thermal isomerization and two hydroxylations. the first hydroxylation occurs in the liver and converts vitamin d to 25-hydroxyvitamin d [25(oh)d], also known as calcidiol. physiologically active 1,25-dihydroxyvitamin d [1, 25(oh) 2d], or calcitriol, is then synthesized primarily in the kidney. the importance of vitamin d for calcium absorption and bone health is undisputed [2, 3] . the classic function of vitamin d is to promote calcium absorption in the gut and maintain adequate serum calcium and phosphate concentrations necessary for normal mineralization of bone. rickets in children and osteomalacia in adults results from insufficient vitamin d [1•] . together with calcium, vitamin d helps protect this article is part of the topical collection on photodermatology older adults from osteoporosis. there is strong, consistent evidence supporting the role of vitamin d in childhood bone health, although most studies have been done in a limited range of skin types, as exemplified in a very recent report showing that high-dose vitamin d supplementation during pregnancy improved bone health in children [4] . in this case, all participants were white and danish. globally, rickets and vitamin d deficiency remain a significant public health problem even in highly developed countries [5••] , despite much research and many government and nongovernmentally funded programs. in europe, little vitamin d is made endogenously in the skin of individuals during the winter months [1•] , and yet vitamin d fortification of foods is largely absent. in the view of many scientists in the vitamin d field, the recommended dietary allowance is too low. recommendations for vitamin d3 at 2000 iu/day are being considered, an intake which should be safe and remain below toxic levels [1•] . factors contributing to a modern "third wave" of rickets have been reviewed recently [5••] from prospective surveillance studies of vitamin d deficiency rickets in australia, canada, and new zealand, as well as multiple retrospective studies from across the globe. in part, this third wave is believed to be caused by reduced uvb exposure due to sun avoidance (sunscreen, clothing, cultural behavior) and a shift toward indoor work. malabsorption syndromes such as celiac disease, short bowel syndrome, gastric bypass, and cystic fibrosis can trigger vitamin d deficiency [6] . medications such as phenobarbital, carbamazepine, dexamethasone, nifedipine, spironolactone, clotrimazole, and rifampin induce hepatic p450 enzymes which can accelerate the degradation of vitamin d and thereby lead to vitamin d deficiency. chronic liver disease and chronic kidney disease increase the risk for vitamin d deficiency due to the dependence on these organs for vitamin d activation. the prevalence of patients with vitamin d deficiency is highest in the elderly, obese, nursing home residents, and hospitalized patients [6] . the issue of vitamin d deficiency in populations who have higher melanin content and/or use extensive skin coverage will be discussed separately. according to the nih, serum concentration of 25(oh)d is the best indicator of vitamin d status. it reflects total vitamin d produced cutaneously as well as obtained through food and supplements and has a fairly long circulating half-life of 15 days. 25(oh)d functions as a biomarker of exposure, but it is not clear to what extent 25(oh)d levels also serve as a biomarker of physiological disease or more subtle conditions or indicate the amount of vitamin d stored in body tissues (primarily adipose tissue). in contrast to 25(oh)d, circulating 1,25(oh)2d is not a good indicator of vitamin d status. levels of 1,25(oh)2d do not typically decrease until vitamin d deficiency is severe. table 1 shows the current serum concentrations and interpretations from the institute of medicine [7• ]. in addition, because the two test protocols used to measure 25(oh)d show some variability among laboratories that conduct the analyses, a standard reference material for 25(oh)d was developed to improve confidence in the result [8] . although from table 1 it would appear that there exists one set of ideal values for serum vitamin d, the situation is somewhat more complex. a slightly alternate rule of thumb is the following [6] : levels of 25(oh)d less than 20 ng/ml indicate vitamin d deficiency, while levels below 30 ng/ml indicate vitamin d insufficiency. levels of 25(oh)d between 30 and 50 ng/ml are generally regarded to be optimal levels; however, a number of variables, including race and age, add complexity [6] . a more thorough discussion of vitamin d assay standardization and recommendation guidelines is provided by sempos and binkley [9] . in any case, the categories of vitamin d sufficiency or deficiency are based on the classic function of vitamin d, bone health. again, based on bone health parameters, vitamin d levels can also be referred to as deficient, insufficient, sufficient, or optimal vitamin d status. the severity of vitamin d deficiency is divided into mild, moderate, and severe. but what about other conditions for which vitamin d may have some modifying actions? there are numerous and conflicting studies that suggest that there may be an association between vitamin d deficiency and cancer, cardiovascular disease, diabetes, autoimmune diseases, asthma, atopic dermatitis, and depression. if indeed, vitamin d status is a modifying factor for these health issues, and it cannot be assumed that the ideal 25(oh)d serum values for prevention of rickets and osteomalacia would prevent or modify these other diseases. it is now recognized that many cells in the body express vitamin d receptors (vdr) which modulate cell proliferation, differentiation, and apoptosis and also regulate gene expression associated with modulation of cell growth, neuromuscular and immune function, and inflammation and may help regulate antimicrobial peptides [10••-14] . several cells involved in immune function express vdr and cyp27b1, which suggests that the active form of vitamin d, 1,25(oh)2d, may control immune function at different levels [10••] . vitamin d is known to regulate parathyroid growth and parathyroid hormone production; it plays a role in the islet cells of the pancreas and may help in suppression of certain autoimmune diseases and some cancers. there are many suggestions that deficiencies in vitamin d levels are linked to conditions such as rheumatoid arthritis, multiple sclerosis, alzheimer's disease, and schizophrenia (for reviews, see [10••, 13••]). prospective studies have reported inverse correlations between 25(oh)d serum levels and cardiovascular disease, serum lipids, inflammation, disorders of glucose metabolism, weight gain, mood disorders, declining cognitive function, and alzheimer's disease. however, no effect of vitamin d supplementation has been demonstrated for these outcomes, so the proximal relationship could be genetic, cultural behavior, or other confounding. first suggested over 30 years ago, vitamin d is now often referred to as a "wellknown" regulator of innate immunity [10••] . the apparent mechanism for this is vitamin d enhancement of defensin β2 and cathelicidin antimicrobial peptide (camp) production, increasing their antimicrobial activity [15] . a thorough review of vitamin d's regulatory function in both innate and acquired immunity can be found in wei and christakos [15] . the biologically active form of vitamin d, 1,25(oh)2d, modulates innate and adaptive immunity via regulation of at least 15 genes by the vdr [16] . 1,25(oh)2d upregulates camp not only in monocytes/ macrophages but also in other cells participating in the innate immune system. that said, there are insufficient data at this time to recommend any specific vitamin d dosage or treatment regimen for asthma, autoimmune diseases, multiple sclerosis, or other conditions. there is confusing and sometimes contradictory evidence for the therapeutic use of vitamin d to treat nonskeletal conditions. for example, although treatment with 1,25(oh)2d was shown to be effective in reducing respiratory infections in asthma patients, and suboptimal serum 25(oh)d in childhood may have adverse effects on tuberculosis and asthma, vitamin d supplementation in pregnancy does not appear to prevent school-age asthma [17] . in a study on vitamin d levels and susceptibility to asthma and atopic dermatitis, no evidence was found for genetically determined low 25(oh)d levels to be linked to an increased risk of either conditions [18] . initial reports indicate that vitamin d and omega-3 supplements failed to reduce risk of cancer or heart events in a 5-year trial of nearly 26,000 healthy us adults [19] . this is, in part, why there is currently active discussion over both the recommended levels of vitamin d as well as the testing methods used to assess adequacy for health and prevention of diseases. recommendations for optimum vitamin d levels, for obtaining a healthy level of vitamin d and even for assessment methods, are currently not uniform across the globe. to some extent, this is because relevant factors vary: vitamin d food fortification regulations, the strength of ambient ultraviolet radiation (uvr), levels of smog, culture and ethnicity, skin phototype, chronological age, and ease and accuracy of specific clinical laboratory measurements. for example, some geographic regions with strong sun have a very high prevalence of rickets [20] . the american academy of dermatology (aad) is regarded as a primary resource for good practice in the field of skin health and related medical specialties. the aad position statement on vitamin d can be accessed online [21] and lists the recommended dietary allowance (rda) and the upper limit values for both calcium and vitamin d intake that should cover "97.5% of the normal healthy population." the optimum vitamin d intake varies by age: for children under 1 year, the rda is 400 iu/day; between 1 year and 70 years, the rda is 600 iu/day; and for people over 70, the rda is 800 iu/day. these rda guidelines are based on aad guidelines that promote minimal or no sun exposure primarily due to the risk of skin cancer associated with sun exposure. the american cancer society also does not support increasing vitamin d levels through sun exposure. the cancer council of australia has slightly eased its sun protection message concerning sunscreen, outdoor clothing, and hats. protection from the sun is currently recommended by the world health organization when the uvr index is ≥ 3 [22] . in general, the paradigm accepted is that an initial linear dose-response relationship exists between exposure to uv radiation and change in concentration of 25(oh)d, followed by a plateau with continuing exposures over a longer period of time. because uvr from the sun and tanning beds can lead to the development of skin cancer, sun exposure (natural) or indoor tanning (artificial) is strongly discouraged. instead, it is recommended that vitamin d be supplied from a "healthy diet," which includes naturally enriched vitamin d foods, fortified foods and beverages, and/or vitamin supplements while practicing sun protection. unfortunately, it is almost impossible to achieve a satisfactory vitamin d intake from diet alone, since it is found at significant levels in only a few commonly consumed foods. fat-soluble molecule is found almost exclusively in oily fish such as salmon, sardines, herring and mackerel, liver, egg yolks, and fortified foods. since dietary sources are unlikely to be sufficient, especially for vegetarians and vegans, supplements are necessary to obtain the rda. the us department of agriculture's (usda's) websites (https:// fdc.nal.usda.gov/index.html.) can be searched for recommended healthy eating guidelines, the nutrient content of many foods, and a list of foods containing vitamin d. in contrast, one comprehensive review [6] concluded that 30 min of sunshine daily with over 40% of skin surface area is required to prevent vitamin d deficiency (although surface area numbers seem to vary greatly). the difficulty of promulgating simple blanket recommendations as pathways to optimal vitamin d status is well described by macdonald et al. [23] . this same reference describes a survey of multiple ethnic groups which demonstrated the difficulty (if not impossibility) of reaching optimal vitamin d levels if no sun exposure is considered safe. most women would find it almost impossible to achieve satisfactory vitamin d status if they had to rely on their current diets. other measures including fortification of additional foods may have to be considered. several different vitamin d fortification programs have been initiated across the globe [24] . in contrast to the aad guidelines that advise against any sun exposure, recommendations from the national health service of the uk [25] states this: "from about late march/early april to the end of september, most people should be able to get all the vitamin d we need from sunlight." clearly, one issue that is immediately apparent is the seasonality of vitamin d levels in certain latitudes. this brings up other key questions in the world of vitamin d. is there such a thing as "sensible" sun exposure? are vitamin d guidelines a "one size fits all" or should they be more nuanced to respect the range of human pigmentation and culture? for example, the recommendations and sufficiency numbers do not take into account an almost complete lack of data from africa and south america [13••] . one recent editorial goes so far as to say that "vitamin d guidelines development is in a state of paralysis" due to a lack of agreement on the parameters for the terms insufficiency, sufficiency, and toxicity based on 25(oh)d concentrations [9] . further, the commentary urges that a set of recommendations based on work of the vitamin d standardization program (vdsp) paves the way for development of rational universal vitamin d status guidelines. although it is believed that most vitamin d (about 80%) is acquired from solar exposure, sunscreen use is an important tool in prevention of skin cancer and is strongly recommended by the dermatology community. uvb wavelengths (280-320 nm) are absorbed by dna and result in direct damage in the form of cyclobutane pyrimidine dimers (cpds) and other mutagenic events that ultimately lead to nonmelanoma skin cancer and melanoma. uva wavelengths (320-400 nm) generate oxidative stress which is associated primarily with photoaging but can also promote skin cancer. unfortunately, the same uvb wavelengths absorbed by dna and that cause dna mutations are also those that induce photoconversion of 7-dehydrocholesterol, to previtamin d3. one of the most important questions to ask then, with regard to the issue of sun avoidance and vitamin d, is directed toward the balance between (a) sunscreen use and uvr generation of vitamin d and (b) the efficacy of sunscreen to prevent uvr-induced dna damage. a consensus review published in 2019 [26] concluded that broad-spectrum sunscreens (with high uva filters) that prevent erythema are unlikely to compromise vitamin d status in healthy populations and that daily and recreational photoprotection does not compromise vitamin d synthesis. vitamin d screening should be used to monitor patients with photosensitivity disorders, who require the most rigorous photoprotection combined with vitamin d supplements [27••] . improved vitamin d status by uvr is always associated with the possibility of higher dna damage and skin cancers; however, production of vitamin d may be optimized and skin dna damage minimized, by increasing the body surface area exposed and decreasing the uvb dose per unit area [13••] . one group has examined the relationship between sunscreen use and vitamin d production in some detail [26, 28••, 29] . a study of sunscreen use in polish volunteers on vacation in tenerife had both interventional and observational groups and was able to monitor the effect of two spf 15 sunscreens over 1 week [26, 29] . one sunscreen had a high uva protection factor (uva-pf), while the second had low uva protection. the authors were able to make the important conclusion that sunscreens may be used to prevent sunburn yet allow vitamin d synthesis, although with the caveat that the absence of sunburn does not necessarily mean the absence of dna mutations [30] . however, concern about unrepaired mutagenic dna lesions should be tempered by evidence that efficient repair occurs within 12 to 48 h, although there is significant individual variation in this ability [30] . in the tenerife study, both high uva and low uva sunscreens prevented sunburn, but subjects using the high uva sunscreen had higher levels of serum 25(oh)d at the conclusion of the study. these findings were attributed to the fact that high uva sunscreen allows transmission of more uvb than low uva sunscreen. another very important study on sun exposure and vitamin d levels followed polish children over 12 days at a baltic sea summer camp [31] . relatively low daily uv radiation doses resulted in a modest but significant improvement in 25(oh)d (24%) but a very much greater increase in cpd (1162%). dna damage was worse in skin types i/ii. this conundrum is reflected in a recent global consensus on rickets prevention that was unable to recommend a safe uvr exposure level to enhance vitamin d status [32] . it has been argued, following in vitro assays, that vitamin d itself reduces the risk of skin cancer by several mechanisms [33] [34] [35] . under laboratory conditions, dna photolesions can be reduced in irradiated skin cells treated with 1,25(oh)2d. one mechanism for this may relate to the increases in p53 and nucleotide excision repair observed within hours after uvr exposure in keratinocytes and melanocytes treated with 1,25(oh)2d (1 or 10 nm) or vitamin d analogs. there was a corresponding reduction in cpds in uv-irradiated skin cells treated with vitamin d compounds. the indirect dna damage and the reduction in dna repair that is normally caused by nitric oxide products may also be reduced by vitamin d compounds. a group in cleveland reported data from an exploratory study in which high oral doses of vitamin d3 resulted in a sustained reduction in skin redness after experimental sunburn, as well as less epidermal structural damage, reduced expression of pro-inflammatory markers in the skin, and a gene expression profile characterized by upregulation of skin barrier repair genes [11] . one barrier to establishing recommendations for sensible sun exposure is the impact of human skin pigmentation and genetic polymorphisms on the response to uvr. these are still largely unknown variables. a careful literature review of vitamin d and the impact of pigmentation was published in 2015 [36•] and noted that a better understanding of how and how much melanin influences vitamin d photosynthesis is critical to meaningful public health messages. the research is difficult to integrate due to variations in study methodology, including the source, dose and frequency of uv irradiation, phototype classification, measurement methods for vitamin d, and the lack of information on relevant genetic polymorphisms. however, on balance, the review team concluded that m o r e h i g hl y p i g m e n t e d s ki n h as l es s e f f e ct i v e photoproduction of vitamin d and 25-hydroxyvitamin d. the ratio of sun exposure to pigmentation level to achieve vitamin d sufficiency remains uncertain. a recent 4-week study of 71 school children [37] controlled for time spent outdoors and assessed the contribution of clothing coverage, initial vitamin d levels, skin color, and other variables to the serum vitamin d levels at the conclusion of the study. the subjects were fitzpatrick skin phototypes iv and v with a range of melanin levels. for all subjects, there was a significant increase in serum 25(oh)d at the conclusion of the study compared with baseline, and a greater increase in serum vitamin d was seen in children with the lowest initial values. melanin levels were inversely correlated with the increase in vitamin d levels. in a study of racially diverse children in boston, most of the variability in 25(oh)d was correlated with constitutive skin color [38] . the correlation between skin color and serum levels of 25(oh)d is usually attributed to the photoprotective properties of melanin. however, there may be additional variables in play which may influence the ultimate health consequences. in a recent study, black americans (n = 2085) had lower concentrations of 25 (oh)d, but also lower concentrations of vitamin d binding protein, than white americans. the consequence of this was similar (calculated) levels of bioavailable 25(oh)d. this may explain why people of color with low total 25(oh)d had a higher average bone mineral density than the white group with similar 25(oh)d concentrations. furthermore, it may imply that bone health is more accurately reflected by the concentration of bioavailable, rather than total, 25(oh)d. taken together, the limited data available suggests that there should be some caution about attributing the observed lower levels of vitamin d in skin of color (soc) simply to a blocking effect of melanin. a very recent rigorously performed and analyzed study was just published that indicates melanin to have less impact on vitamin d levels than previously thought, possibly due to the spatial positions of melanin and 7-dehydrocholesterol in human skin [39••] . a brief review of confounding related to the question of pigment, uvrrelated skin cancers, and serum vitamin d levels can also be found in a 2015 review [13••] . the role of vitamin d as a possible modulator of susceptibility, morbidity, and mortality in sars-cov-2 (covid19) that vitamin d should play a role in covid-19 is not unexpected, since there has been believed to be a link between vitamin d deficiency and respiratory disease for over 100 years. observational studies have reported independent associations between low serum concentration of 25hydroxyvitamin d and susceptibility to acute respiratory tract infections [40] . vitamin d deficiency is associated with an increased risk of the acute respiratory distress syndrome (ards), intensive care admission, and mortality in patients with pneumonia [41] . in a systematic review and metaanalysis of 25 randomized controlled studies, martineau et al. found that vitamin d protected against acute respiratory tract infection overall [42] . patients who were severely vitamin d deficient experienced the most benefit. subgroup analysis revealed that daily or weekly vitamin d supplementation without additional bolus doses protected against acute respiratory tract infection, whereas regimens containing large bolus doses did not. among those receiving daily or weekly vitamin d, protective effects were strongest in those with profound vitamin d deficiency at baseline, although those with higher baseline 25-hydroxyvitamin d concentrations also experienced benefit. the interaction of vitamin d status and susceptibility to sars-cov-2 is currently being investigated [43-45••] . most immune cells express the vdr and actively convert 25(oh)d into 1,25(oh)2d, its active form. vdr signaling has a suppressive role on autoimmunity and an antiinflammatory effect, promoting dendritic cell and regulatory t cell differentiation and reducing th 17 cell response and inflammatory cytokine secretion (with relevance to the covid-19 induced cytokine storm). also mentioned earlier, vitamin d is thought to have a regulatory effect on innate immunity. there is no general consensus on the desired level of 25(oh)d to achieve immunomodulatory effects; thus, there is no current indication for vitamin d supplementation in specific infections and/or autoimmune diseases. however, dr. anthony fauci, director of the national institute of allergy and infectious diseases, in a recent interview by jama, agreed that "if you are vitamin d deficient, you might have a poor outcome or a greater chance of getting into trouble with an infection" (jama medical news & perspectives, june 8, 2020). the most vulnerable group with respect to covid-19, the aging population, also has a high proportion of individuals with deficient vitamin d levels. further studies have been both proposed (at least one clinical trial is registered with the nih) and initiated to clarify the contribution of vitamin d levels to susceptibility and the severity of response to covid-19 as well as the use of vitamin d supplementation as a possible therapeutic agent [43••-45••]. vitamin d deficiency is a major global public health issue with vitamin d deficiency rickets at significant levels even in highly developed countries. about 1 billion people worldwide have vitamin d deficiency, while 50% of the population has vitamin d insufficiency. the fact that exposure of the skin to uvb radiation, wavelengths that cause mutations in the dna of epidermal cells, is also the source of vitamin d is problematic. can the average person finely calibrate 0.2 minimal erythema dose, the point at which vitamin d synthesis occurs without perceptible dna damage? for relevant nonskeletal conditions or diseases such as multiple sclerosis, alzheimer's disease, or even ards, it is unknown whether low vitamin d status causes the disease or the disease causes the low vitamin d status. communication with patients about vitamin d calls for judgment and individualization in patient care, including more nuanced advice about sun exposure. human and animal rights and informed consent this article does not contain any studies with human or animal subjects performed by any of the authors. this is a generally helpful primer on the classic functions and understanding of vitamin d vitamin d and health: the need for more randomized controlled trials serum cholecalciferol may be a better marker of vitamin d status than 25-hydroxyvitamin d effect of high-dose vs standard-dose vitamin d supplementation in pregnancy on bone mineralization in offspring until age 6 years: a prespecified secondary analysis of a double-blinded, randomized clinical trial a brief history of nutritional rickets vitamin d deficiency medicine committee to review dietary reference intakes for vitamin d, calcium. the national academies collection: reports funded by national institutes of health nist releases vitamin d standard reference material. nist 25-hydroxyvitamin d assay standardisation and vitamin d guidelines paralysis vitamin d: nutrient, hormone, and immunomodulator oral vitamin d rapidly attenuates inflammation from sunburn: an interventional study control of cutaneous antimicrobial peptides by vitamin d3 the consequences for human health of stratospheric ozone depletion in association with other environmental factors cyp11a1 in skin: an alternative route to photoprotection by vitamin d compounds mechanisms underlying the regulation of innate and adaptive immunity by vitamin d key vitamin d target genes with functions in the immune system vitamin d supplementation in pregnancy does not prevent school-age asthma vitamin d levels and susceptibility to asthma, elevated immunoglobulin e levels, and atopic dermatitis: a mendelian randomization study study questions the benefits of vitamin d and omega 3 supplements. cardiosmart news american college of cardiology the effect of high-dose postpartum maternal vitamin d supplementation alone compared with maternal plus infant vitamin d supplementation in breastfeeding infants in a high-risk population. a randomized controlled trial o / dfff5f47b0dddfb82676270505afd09f/ps-vitamin_d_postition_ statement.pdf 22. ultraviolet (uv) index. world health organization sunlight and dietary contributions to the seasonal vitamin d status of cohorts of healthy postmenopausal women living at northerly latitudes: a major cause for concern? vitamin d microencapsulation and fortification: trends and technologies how to get vitamin d from sunlight sunscreen photoprotection and vitamin d status an important discussion of study protocol variables and their influence on policy sub-optimal application of a high spf sunscreen prevents epidermal dna damage in vivo optimal sunscreen use, during a sun holiday with a very high ultraviolet index, allows vitamin d synthesis without sunburn kinetics of uv light-induced cyclobutane pyrimidine dimers in human skin in vivo: an immunohistochemical analysis of both epidermis and dermis children sustain high levels of skin dna photodamage, with a modest increase of serum 25-hydroxyvitamin d3, after a summer holiday in northern europe global consensus recommendations on prevention and management of nutritional rickets vitamin d and death by sunshine protective effects of 1,25 dihydroxyvitamin d3 and its analogs on ultraviolet radiation-induced oxidative stress: a review photoprotective properties of vitamin d and lumisterol hydroxyderivatives a systematic review of the influence of skin pigmentation on changes in the concentrations of vitamin d and 25-hydroxyvitamin d in plasma/serum following experimental uv irradiation impact of solar ultraviolet b radiation (290-320 nm) on vitamin d synthesis in children with type iv and v skin association of serum 25-hydroxyvitamin d with race/ethnicity and constitutive skin color in urban schoolchildren melanin has a small inhibitory effect on cutaneous vitamin d synthesis: a comparison of extreme phenotypes vitamin d(3) supplementation reduces the symptoms of upper respiratory tract infection during winter training in vitamin d-insufficient taekwondo athletes: a randomized controlled trial vitamin d deficiency contributes directly to the acute respiratory distress syndrome (ards) vitamin d supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data evidence that vitamin d supplementation could reduce risk of influenza and covid-19 infections and deaths covid-19 and vitamin d-is there a link and an opportunity for intervention? letter: covid-19, and vitamin d publisher's note springer nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations key: cord-345120-fa5sx5zm authors: simonson, william title: vitamin c and coronavirus date: 2020-05-08 journal: geriatr nurs doi: 10.1016/j.gerinurse.2020.05.002 sha: doc_id: 345120 cord_uid: fa5sx5zm nan when deciding on a topic for this issue's column it seemed obvious to me to address some aspect of the elephant in the room… severe acute respiratory syndrome coronavirus 2 (sars-cov-2) or "covid-19." there are so many aspects of the virus ….. which particular aspect of the topic should i address? ultimately, the virus will only be fully-controlled when a safe and effective vaccine is available. experts say that this will take at least 12-18 months, which is still record time for development of a vaccine. perhaps it is wishful thinking on my part but i think such a vaccine might be available in less than one year. for what it's worth, i just heard an interview where the subject said that a vaccine may be available for first responders by this autumn….let's hope so. i have faith in the universities, private research laboratories and biotech companies working towards conquering this pandemic. it will be conquered and in-the-process the amazing leaps in knowledge that will come out of this will result in a much better understanding of virus infections which will help prevent a disaster like this from occurring again. in the meantime, as a stopgap measure, one or more therapeutic options may provide at least temporary control. to date there are no such proven options for prophylaxis or treatment but there are a rapidly growing number of possible therapies being discussed, researched and sometimes touted with little or no scientific rationale. some of these potential therapies are old, perhaps repurposed pharmaceuticals, while some are high-tech, modern biologic agents that represent new approaches to control viral infections. for example, one proven approach for treating certain 2 infectious diseases, including other coronaviruses, is the administration of convalescent plasma, collected from individuals who have recovered from an infection and are therefore able to make the appropriate antibodies which are then collected and given to those who have not yet been infected to provide them with passive immunity. 1 it is hoped that this approach will be effective in treating coronavirus as it has been with other infectious diseases. development of monoclonal antibodies specifically engineered to block the virus are another option as is the use of existing biologic products already indicated for conditions such as hiv and various cancers. it would be wonderful if one or more of these agents is able to block the virus to prevent infection or treat sick patients but one course of therapy from some of these biologicals may have a price tag of many thousands of dollars. this would add countless dollars to the global price tag that already amounts to trillions of dollars. other possible therapies or adjuncts include zinc, chloroquine and hydroxychloroquine, the efficacy of which has not been proven and is less based on science than it is on "hunches and feelings" which is clearly not a scientific approach. distressingly, to some people, the use of particular agents over others has become a partisan issue which i am having difficulty comprehending. all this being said, i decided to focus on a product that has been proposed to prevent or treat covid-19 and is indeed already used in clinical practice. after all, what's not to like about this popular vitamin, vitamin c? most of the readers have a bottle of vitamin c tablets in their medicine cabinets. my mom was a strong believer in the benefits of vitamin c and always encouraged me to take supplements or consume foods rich in the vitamin such as orange juice. another reason for my selection of this topic is that vitamin c was made famous by dr. linus pauling who graduated from the university where i am on faculty, oregon state university. this institution houses the linus pauling institute. 3 vitamin c has been studied for many years and we know that it is an important cofactor involved in the formation of blood vessels, cartilage, muscle and collagen in bone and is vital for the healing process. as an anti-oxidant, the vitamin might help protect cells from damage by chemical free radicals. it is thought that these chemicals contribute to heart disease, cancer and other diseases. possible beneficial effects attributed to vitamin c include reducing endothelial dysfunction, managing hypertension, reducing cardiovascular disease risk, and preventing stroke, certain types of cancer, diabetes, gout and possibly even alzheimer's disease. the data on these possible therapeutics is often controversial and/or conflicting and it is not entirely clear if benefits are at least partially the result of improved nutrition. overall, regular use of vitamin c supplements shortens the duration of the common cold but does not reduce the risk of contracting a cold except in persons undergoing heavy physical stress (e.g. marathon runners, skiers, or soldiers in subarctic conditions) where the incidence of colds is cut in half. taking vitamin c supplements once cold symptoms have already begun has no proven benefits. 2 it is likely that this antiviral effect is why vitamin c has attracted interest as a possible treatment of covid-19. the recommended daily allowance for vitamin c intake is 90 mg. for adult men and 75 mg. for adult women with an additional daily 35 mg. for smokers of either gender. 2 the linus pauling institute recommends a daily vitamin c intake or at least 400 mg for adults >50 years. dr. pauling's dosing recommendation suggested that optimum daily intake may be about 2,000 mg but he noted that the first 250 mg is most important for achieving satisfactory serum levels. 3 others recommend and are administering dosages that are much higher as discussed below. while anecdotal reports about the effects of medications are compelling, and provide what may appear to be convincing evidence that a particular medication or therapy possesses a specific 4 therapeutic or negative effect, it is important not to get misled. it is important to re-emphasize that association does not mean causation. while anecdotal evidence is tempting to believe and may actually demonstrate an effect that is real, the proof of a drug's effect is only achieved through blinded, controlled studies published in peer-reviewed scientific journals. a recent scientific article published in 2019 before the detection of the novel coronavirus presents a metaanalysis of 18 controlled clinical trials with a total of more than 2000 patients looking at the effect of vitamin c on length of stay in the hospital intensive care unit and the duration of mechanical ventilation. study results included the following: in 12 of the trials reviewed, length of icu stay was reduced by 7.8% in patients receiving vitamin c. this was highly statistically significant. in six trials the length of icu stay was reduced by 8.6% following oral administration of vitamin c in doses of 1 -3 gm/day. in three trials in which patients needed mechanical ventilation for over 24 hours vitamin c shortened the duration of mechanical ventilation by 18.2%. all this data was highly statistically significant. 4 this study did not include covid-19 patients but the authors suggested that the effects of vitamin c on icu patients should be investigated in more detail based on study results and what they refer to as the insignificant cost of vitamin c. it would be important to study this in patients with covid-19 infection. in a youtube video interview, ron hunninghake, md, medical director of the riordan clinic, a nutrition-based health facility in kansas, stated that most doctors and medical schools are biased against nutritional medicine and that vitamin c is more likely to be adopted as a component of medical practice that could be referred to as nutritional, integrative, or wholistic medicine. 5 hunninghake refers the viewer to a recent study published in jama that showed that intravenous administration of 1.5 gm vitamin c every 6 hours significantly decreased mortality 5 rate of septic patients with acute respiratory distress syndrome by 30%. 6 dr. hunninghake reports administering intravenous vitamin c to 250,000 patients over his 31 years of practice and describes vitamin c as "the paramount rescue molecule in nature." his current protocol is to administer 7.5 gm. of vitamin c in 50 cc of fluid over 3-5 minutes and that patients tolerate this therapy very well including virtually no development of kidney stones. at least some hospital systems have adopted administration of vitamin c in patients infected with covid-19. a ny newspaper reports that seriously sick patients in ny city's largest hospital system are being given vitamin c. a pulmonologist and critical care specialist dr. andrew g. weber said that his intensive-care patients with the coronavirus immediately receive 1,500 mg of vitamin c, administered intravenously, with that dose repeated three or four times a day. dr. weber stated, "the patients who received vitamin c did significantly better than those who did not get vitamin c." since vitamin c levels in the body of coronavirus patients drops dramatically when sepsis develops, dr. weber adds "it makes all the sense in the world to try to maintain vitamin c levels in the body." further comment from a spokesperson from northwell which operates 23 ny hospitals stated that vitamin c was being "widely used" throughout the system with protocols varying according to the clinician's orders. 7 to conclusively determine whether vitamin c therapy is beneficial for treatment of covid-19 a double-blind placebo-controlled study is needed. indeed, such a study has been designed and recruitment of subjects began on february 14, 2020. 8 study design calls for intravenous administration of either 12 gm. of vitamin c or placebo to patients with severe pneumonia due to covid-19 infection twice a day for 7 days. the study is projected to be completed by september 30, 2020 so, in the not-too-distant future, we should know whether this intensive high-dose vitamin c therapy is effective in treating covid-19. of course, question will still remain re: whether more frequent intravenous dosing is 6 effective or whether oral vitamin c should be given as a preventive measure for infection and, if so, what dose should be used. until then, individual consumers need to make their own decisions based on available data. as with all medications, a key component of this decision will be an analysis of potential risk v. potential benefit. i know that i'm going to follow mom's advice and continue to take my vitamin c tablet every day. deployment of convalescent plasma for the prevention and treatment of covid-19 linus pauling institute, micronutrient center vitamin c can shorten the length of stay in the icu: a metaanalysis you tube interview of ron hunninghake effect of vitamin c infusion on organ failure and biomarkers of inflammation and vascular injury in patients with sepsis and severe acute respiratory failure: the citris-ali randomized clinical trial new york hospitals treating patients with vitamin c. ny post vitamin c infusion for the treatment of severe 2019-ncov infected pneumonia key: cord-018204-rqp4huk3 authors: balan, k. v.; babu, u. s.; godar, d. e.; calvo, m. s. title: vitamin d and respiratory infections in infants and toddlers: a nutri-shine perspective date: 2013 journal: handbook of vitamin d in human health doi: 10.3920/978-90-8686-765-3_16 sha: doc_id: 18204 cord_uid: rqp4huk3 there is compelling evidence of a global problem of poor vitamin d status in expecting mothers and postnatal life; and even more critical, is the evidence showing the association of vitamin d deficiency with increased morbidity and mortality risks from respiratory infections. viral and bacterial pneumonia kills more children than any other illness, accounting for 19 % of all deaths in children less than five years of age worldwide; and under-nutrition, which includes vitamin d insufficiency/deficiency, has been implicated in 53 % of all these deaths. poor vitamin d status is a result of insufficient sunlight exposure and/or poor dietary intake. greater understanding of the role of vitamin d deficiency in precipitating lung infections grew from the use of rodent models and observational and intervention studies in infants and toddlers. vitamin d adequacy is important to maintaining the key protective mechanism of developing lungs since it mediates the synthesis of antimicrobial peptides, the lungs strongest defense against viral and bacterial pathogens. if vitamin d intervention currently under study in several clinical trials is proven successful, then implementation of new fortification practices, revised guidelines for healthy sun exposure and public health programs for vitamin d supplementation of pregnant/lactating women and their infants may be effective strategies to aide in preventing neonates and children under five from developing pneumonia. globally, there is potential to save more than a million young lives with preventive treatment, a compelling reason why the efficacy of optimizing vitamin d mediated defense against respiratory pathogens in infants and children merits further study. vitamin d status of mothers and infants is poorest in darker skinned individuals, particularly those living in northern latitudes. the poorest vitamin d status occurs in exclusively breast fed infants who are not supplemented with vitamin d. in contrast, formula fed infants have lower prevalence of vitamin d deficiency; however, older toddlers have limited access to vitamin d-rich foods. children with fitzpatrick skin types ii to iv, in the northern and southern united states can only achieve a minimum amount of vitamin d from sun exposure during the summer months if they do not wear sunscreen at all except during beach vacations. dark-skinned (skin types ≥ v), children fall short of achieving their needs for vitamin d from sun exposure year round. in vivo animal and in vitro models provide evidence that vitamin d deficiency in utero is associated with altered lung development and immune functions, and increasing postnatal susceptibility to respiratory infections. adequate vitamin d is critical for the production of anti-microbial peptides such as cathelicidin and betadefensins that are key protective mechanisms in preventing respiratory infections in children under five years of age. clinical trials are currently underway to determine if vitamin d supplementation reduces respiratory tract infections in infants and toddlers and during gestation in supplemented pregnant or lactating mothers. and toddlers: a nutri-shine perspective 16 . vitamin d is a secosteroid hormone that is synthesized in humans upon solar uvb (290-315 nm) mediated conversion of endogenous skin 7-dehydrocholesterol to cholecalciferol (vitamin d3) (maclaughlin et al., 1982) , and is also derived from food and dietary supplements. during the winter when adequate sunlight is limited for synthesis, there is greater dependency on dietary intake and thus the term 'vitamin' meaning essential nutrient was applied to this sunshinederived hormone. since vitamin d occurs naturally in a limited number of foods, fortified foods such as milk and milk products, margarines, and breakfast cereals constitute the major dietary sources of the two forms of vitamin d, cholecalciferol or ergocalciferol (vitamin d2) in the us and canada (calvo et al., 2004) . after absorption or synthesis, vitamin d2 or d3 is transported by vitamin d binding protein to the liver where the enzyme 25-hydroxylase converts it to 25(oh)d. this intermediary metabolite circulates and delivers the precursor to the active or hormonal form of vitamin d to different tissues. in this capacity, plasma 25(oh)d serves as the main status indicator for vitamin d. the mitochondrial enzyme, 1α-hydroxylase converts 25(oh)d to the active form of vitamin d, 1,25(oh) 2 d (holick, 2007) . renal tissues are thought to be the major source of circulating levels of 1,25(oh) 2 d, but most extra-renal tissues including the immune and airway epithelial cells constitutively or upon activation express 1α-hydroxylase and can produce 1,25(oh) 2 d (hansdottir and monick, 2011) . vitamin d has pleiotropic functions, and is involved in the regulation of approximately 1000 human genes (tavera-mendoza and white, 2007) , including genes associated with immune responses and lung development. while its classical role in bone mineralization is well documented, the interplay of non-rachitic vitamin d status to in utero and post-natal health outcomes such as susceptibility to early-life respiratory infections continues to evolve. in this chapter, we review the current public health concern about vitamin d status in infants and toddlers in north america, the dietary guidelines and federal regulations governing the level of vitamin d in foods and supplements during pregnancy and early childhood, and examine the evidence for association between poor vitamin d status and risk of respiratory infections in infants and toddlers. plasma 25(oh)d is considered the best biomarker for vitamin d status as it is relatively stable and reflects contributions from all sources of vitamin d (diet and endogenous synthesis). the iom, an independent non-governmental body, recently defined adequate vitamin d status as having serum 25(oh)d concentrations greater than 50 nmol/l (or 20 ng/ml; 1 ng/ml = 2.5 nmol 25(oh)d/l) in both the general population and pregnant women, and concentrations between 30-49 nmol/l (or 12-20 ng/ml) or <30 nmol/l (or <12 ng/ml) were considered to be inadequate or deficient respectively (iom, 2011) . the iom cutoff levels defining adequate, insufficient and deficient plasma vitamin d status are specific to bone health and do not consider other systems that are affected by circulating levels of 25(oh)d such as the immune system and respiratory health (iom, 2011) . although serum 25(oh)d levels of at least 25 nmol/l prevents rickets, it has been proposed by some investigators that concentrations around 80 nmol/l (32 ng/ml) are optimal, since these levels lead to the greatest calcium absorption and the highest bone mass (bischoff-ferrari et al., 2006; dawson-hughes, 2008) and are associated with better health outcomes involving non-skeletal tissue (hollis, 2011 ). an accurate determination of the overall dietary requirements for maintaining vitamin d adequacy is impossible because of substantial variation in skin synthesis due to season, location, age, duration of exposure, pollution, skin pigmentation and exposed area, and use of sun screen. consequently, assuming minimal sun exposure and after thorough review of literature on skeletal health, the iom established a rda of 600 iu (15 μg; 1 μg=40 iu vitamin d2 or d3) vitamin d for pregnant and lactating women and toddlers. with insufficient evidence to develop an rda in infants, an adequate intake of 400 iu (10 μg) was proposed to ensure vitamin d nutritional adequacy in this population. the iom derives the rda from an ear, which was determined for vitamin d for the first time in 2011. from a public health perspective the ear (400 iu or 10 μg/d for individuals >1 year) is used to evaluate the nutrient intake adequacy of a population at the 50 th percentile (median) level of intake for all age groups (whiting and calvo, 2011 ). there appears to be global variation in recommended vitamin d intake guidelines for pregnant women, infants and toddlers (table 16 .1). this variation could be a result of differences due to season, demographics of light versus dark skinned individuals, national supplementation and fortification policies, and more importantly skepticism associated with non-skeletal health benefits from basic science experiments and observational studies as compared to randomized clinical trials. maternal vitamin d deficiency during pregnancy is global and widely prevalent, and can be attributed to inadequate vitamin d intake and restricted sunlight exposure during winter months k.v. balan, u.s. babu, d.e. godar and m.s. calvo compared to summer months, northern latitudes, and higher melanin levels in dark-skinned or veiled women. based on a national human activity pattern survey it has been estimated from the outdoor-sunlight data that us women including those of child-bearing age (22-40 years) get lower annual uvb doses than males because they spend less time outdoors (godar, 2001; godar et al., 2001) . in the us, 29% of african-american pregnant women and 5% of caucasian pregnant women residing in the northern latitudes are vitamin d deficient (defined as serum 25(oh)d less than 37.5 nmol/l); whereas 54% of african-american participants and 47% of caucasian participants are vitamin d insufficient (defined as serum 25(oh)d 37.5-80 nmol/l) (bodnar et al., 2007) . moreover, 18% of pregnant women in the united kingdom, 25% in the united arab emirates, 80% in iran, 42% in northern india, 61% in new zealand and 60-84% of pregnant non-western women in the netherlands have been shown to have serum 25(oh)d concentrations <25 nmol/l (dawodu and wagner, 2007) . thus, there is concern that in utero vitamin d deficits could lead to developmental re-programming of body functions and long-term morbidity in infants, children and adults. holick et al., 2011; iom, 1997 iom, , 2011 vidailhet et al., 2012) . year cumulative intake data from the nationally representative nhanes survey conducted from 2007-2008 show that us women of childbearing age have significantly lower (p<0.01) vitamin d intakes than their age-matched male counterparts ( figure 16 .1) (usda, 2010) . a comprehensive assessment of 25(oh)d serum data from participants in nhanes 2001 nhanes -2006 , one year of age and over, after adjusting for age and season, showed that males are less likely to be at risk of deficiency (<30 nmol/l) than females ( figure 16 .2) and the prevalence of those at risk of inadequacy (30-49 nmol/l) did not differ by sex. however, in the 2001-2006 nhanes cohort, among women of childbearing age, those who were pregnant or lactating were less likely to be at risk of deficiency compared to women who were not pregnant or lactating (figure 16 .2) and no differences in prevalence of vitamin d inadequacy were observed between the two groups (looker et al., 2011) . these prevalence data reflect 24 hr recall levels of vitamin d intake, which suggests that pregnant and lactating women in general in the us are in compliance with the current dietary guidelines for maintaining vitamin d status or have adequate sun exposure. a rigorous analysis of current nhanes data is needed to determine the association of vitamin d status with sun exposure and total 'usual' dietary intake for individual race/ethnicities, since smaller cross-sectional studies have shown association of maternal deficiency, race (african-american), winter birth, and a bmi of ≥35 as risk factors for newborn vitamin d deficiency. during pregnancy the fetus is wholly dependent on the mother for vitamin d, and 25(oh)d readily crosses the placenta such that cord blood 25(oh)d levels are between 80% and 100% of maternal concentrations (fleischman et al., 1980; gertner et al., 1980; hillman and haddad, 1974) . there is a strong correlation between maternal and newborn 25(oh)d circulating levels as the half-life of 25(oh)d is approximately 2 to 3 weeks, and a low maternal status often results in the infant being deficient in vitamin d during the first weeks post-partum (hollis and wagner, 2004a; yu et al., 2009) . because vitamin d secretion in breast milk is limited (kovacs, 2008) , lactating women require robust serum 25(oh)d levels to support vitamin d status in nursing infants (hollis and wagner, 2004b) . the world health organization recommends supplementation with 400-iu daily vitamin d to all pregnant women; however, because of lack of awareness and poor compliance, 46% of newborns in industrialized countries are born with insufficient serum levels of 25(oh)d (belderbos et al., 2011) . more recently balk and the council on environmental health and section on dermatology recommended that children younger than 1-year of age avoid direct sunlight and also use sunscreen (balk, 2011) . furthermore, for reasons that are not entirely clear, data suggest that the relationship between vitamin d intake and serum 25(oh)d levels is non-linear (hypponen et al., 2009) , and current guideline levels for vitamin d supplementation (200-600 iu/d) are unlikely to achieve optimal serum 25(oh)d levels (iom, 2011) . in a study of 40 mother-infant pairs, 76% of mothers and 81% of newborns had a 25(oh)d level below 50 nmol/l at the time of birth, despite the fact that during pregnancy the mothers ingested about 600 iu/d of vitamin d from a prenatal supplement and consumed two glasses of milk (lee et al., 2007) . thus, it is understandable that infants who are fed only human breast milk are prone to developing vitamin d deficiency leading to a federal mandate both in the united states and canada to fortify infant formula with vitamin d at 40-100 iu/kcal and 40-80 iu/kcal, respectively. the effectiveness of infant formula fortification was evident in a cross-sectional study of 247 healthy infants in a primary care setting in boston as breastfeeding without supplementation markedly increased the odds of vitamin d deficiency compared with infants who were exclusively formula (bottle)-fed (gordon et al., 2008) . interestingly, although maternal supplementation of 200-iu/d vitamin d was available to all nursing mothers, there may be barriers to obtaining the supplement or lack of awareness of the need to supplement, which resulted in poor compliance. thus, with emerging data on insufficiency in vitamin d levels with the iom 1997 recommendation of 200 iu/d, the revised recommendation is now set at 600 iu/d for infants in the united states and canada (iom, 2011). most american children may not be going outside enough to meet their vitamin d3 needs from sun exposure (godar et al., 2012) . recent estimates from everyday outdoor exposure suggest that children (≤5 years) in the northern (45°n) (figure 16 .3a) and southern (35°n) (figure 16 .3b) united states with fitzpatrick type ii skin (caucasian) (fitzpatrick, 1988) can have adequate skin synthesis of vitamin d3 during the summer and children living in the south during the spring as well but only if they do not wear sunscreen at all except during beach vacations. children with fitzpatrick type iii and iv skin (olive tone-hispanic/asian or brown tone-indian, respectively) average estimated vitamin d3 produced in toddlers (≤5 years of age) from everyday outdoor uv exposures without the use of sunscreens in (a) the northern (45°n) or (b) southern (35°n) united states according to skin type and season. skin types represent fitzpatrick skin types ii (caucasian), iii (olive skin tone, hispanic or asian), iv (brown skin tone, e.g. indian) and v (light to moderate-skinned african american) (fitzpatrick, 1988 can only synthesize the suggested minimum daily recommendation during the summer months, while those with the darkest pigmentation (skin type v and higher, usually african-americans) never make the suggested minimum amount of vitamin d3 from sun exposure (godar et al., 2012) . these vitamin d3 estimates from solar exposures assume certain skin types, liberal clothing scenarios during each season and that sunscreens are not worn except during beach vacations. these could be overestimates for infants and toddlers since mothers tend to be overly protective of their children to avoid skin cancer later in life or could be a result of children spending more time indoors watching television. despite the fact that younger children are spending more time indoor, children in the younger age group (≤5 years) have more cutaneous vitamin d synthesis than those in the older age groups (godar, 2001) . with children falling short of the daily needed levels of vitamin d3 from sunshine exposure especially in the winter months, fortified foods are key to maintain adequate vitamin d status in toddlers, and increasingly, the manufacturers of foods targeted to toddlers are recognizing the need to fortify with vitamin d. levels of vitamin d fortification range from 1 μg (40 iu) per regulatory serving for ready-to-eat cereals to 2.5 μg for fluid milk servings (calvo and whiting, 2013) . it is evident from reviewing the vitamin d content of the 'baby foods' listed in the recent usda database, standard release-24 for nutrient composition of foods that there is a need for newer fortified baby foods. a review of 223 foods showed vitamin d contents ranged from 0 to 0.8 μg vitamin d per 100 g, and approximately 90% had no listed vitamin d content. with the availability of limited fortified baby foods, in a population study of 750 healthy children aged 6-36 months, the mean overall vitamin d intake from food plus supplements was 290±124 iu/d in 6-12 month age group and 240±128 iu/d in 1-3 years age group (figure 16 .4), and group corresponding serum 25(oh)d levels decreased with age. a quite concerning trend in this cohort was that children discontinued breastfeeding by 5 months of age and most children (84%) were no longer formula-fed at 5 months (carpenter et al., 2012) . thus, with the iom recommended adequate intake of 400 iu/d for infants and 600 iu/d for toddlers approximately 82% of infants and 2% of toddlers met the age-specific dietary intake recommendation. these findings suggest that vitamin d-fortified infant formulas provide a positive effect on vitamin d levels and similar supplementary practices are likely to be effective in increasing 25(oh)d status in young children (carpenter et al., 2012) . the mean intake data for toddlers (2-5 years age) from the nhanes 2007-2008 cohort shows a significant difference in vitamin d intake among the racial and ethnic groups with non-hispanic blacks consuming less than non-hispanic whites, who consume less than mexican americans (figure 16 there is clear evidence for global and widespread vitamin d deficiency or insufficiency due to various risk factors including lack of sunlight exposure, seasonal variation, suboptimal dietary intake, and dark skin pigmentation. more importantly, we have shown the greatest barriers to adequate vitamin d from sun exposure or diet occur in individuals with the poorest vitamin d status. how this widespread deficiency relates to the risk of respiratory tract infections in infants and toddlers is less clear and merits further study. the fetal origins hypothesis, first articulated by david barker, postulates that in utero epigenetic fetal programming, as a result of environmental events during pregnancy, induces specific genes and genomic pathways that control fetal development and subsequent disease risk (barker et al., 2002) . the biological effects of active vitamin d are achieved through the regulation of gene expression in a cell and tissue specific manner. briefly, active vitamin d binds to the vitamin d nuclear receptor, and initiates dimerization with the retinoic x receptor. this active complex binds to the nuclear vitamin d responsive elements within the promoter regions of vitamin d-specific responsive genes and initiates gene expression (macdonald et al., 1993) . the developmental periods of in utero and infancy represent critical periods of dynamic development and maturation of key processes. therefore, in the following sections, we focus on the role of vitamin d in modulating lung structure and innate immune functions, a primer for susceptibility to viral respiratory tract infections during infancy and early childhood (figure 16 .7). lung development occurs predominantly before birth (stick, 2000) with extensive interactions between epithelial and mesenchymal tissue beginning by the fourth week of gestation and continuing for years after birth, and factors that impair fetal and early childhood lung development have the potential to exert major effects on lung function during childhood and adulthood. despite differences in the epithelial growth and differentiation during lung development in rodents and humans, rodent models are widely used for lung developmental studies. rodent models act as a bridge between studies in the laboratory and studies in humans, and have been used to study pulmonary infections (balan et al., 2011) . in rodents, it has been demonstrated that vitamin d modulates key alveolar epithelial-mesenchymal interactions, such as type ii pneumocyte and lipofibroblast proliferation and differentiation which are critical for alveolar development and septal thinning during perinatal pulmonary maturation (sakurai et al., 2009) . vitamin d-deficient rodent models provide mechanistic evidence for a causal link between vitamin d deficiency and deficits in lung function and altered lung structure. specifically, offspring of vitamin d-deficient mice showed no effect on the overall somatic growth, had marginal reduced numbers of alveoli, and exhibited physiologically significant decreases in lung volume and altered lung mechanics when compared with offspring of vitamin d-replete mice (zosky et al., 2011) . this mouse study complements data showing decreased lung compliance in 50-d-old rats born to vitamin d-deficient mothers (gaultier et al., 1984) , confirming the relationship between vitamin d deficiency and lung function. in addition, as vitamin d deficiency has the potential for premature births in humans (dawodu and nath, 2011) , studies have shown that prematurity leads to diminished lung function and may predispose premature infants to severe viral lower respiratory tract infections in infancy (drysdale et al., 2011) . active vitamin d synthesis has been shown in rodent fetal lung fibroblasts, whereas adjacent alveolar type ii pneumocytes express vitamin d receptors and respond to the hormone by undergoing differentiation and maturation resulting in decreased cell glycogen content, and increased surfactant synthesis and secretion (nguyen et al., 1996 (nguyen et al., , 2004 . surfactant proteins were initially identified as a lipoprotein complex that reduced surface tension at the air-liquid interface of the lung, but recent studies have identified surfactant proteins as components of the lung innate and adaptive immune system with novel roles in the direct killing of inhaled microorganisms and viruses, and control of pulmonary inflammation (wright, 2005) . the vitamin d-mediated rodent type ii pneumocyte maturation data looks intriguing but the relevance to humans is uncertain. regulation of surfactant protein gene expression in human fetal type ii pneumocytes by active vitamin d is not coordinated as it is in rodents, but vitamin d receptor immuno-staining is observed in human fetal fibroblasts and type ii pneumocytes (phokela et al., 2005; stio et al., 1997) . thus, there is evidence for in utero vitamin d deficiency and association with altered epithelialmesenchymal maturation, lung mechanics, and immunoregulatory surfactant production. while the association between surfactants in providing innate immunity against respiratory viral infections is conceivable, the role of altered pulmonary function with vitamin d deficiency could also indicate an association with asthma, a chronic inflammatory condition that is described in detail in a separate chapter. the fetus and neonate face a complex set of immunologic demands, and vitamin d has been shown to have an important role in the innate immune system, which helps to prevent infection without the need for immunologic memory from previous exposure to the pathogen (adams and hewison, 2008) . innate immunity includes the production of antimicrobial peptides such as beta-defensins and camp by epithelial cells and circulating leukocytes, which are capable of killing a variety of respiratory pathogens including viruses, bacteria, and fungi (hiemstra, 2007) . in early gestation, human decidual cells have been shown to synthesize active vitamin d, which may exert autocrine or paracrine effects on the developing fetal immune system. vitamin d mediates expression of mrna for camp in decidual cells (evans et al., 2006) , and has been linked to intrauterine immunity (singh et al., 2005) . human monocytes in an in vitro model, when supplemented with 25(oh)d-deficient cord blood plasma showed a significant decrease in camp expression, thus correlating with increased susceptibility to newborn infections (walker et al., 2011) . in postnatal life, respiratory epithelial cells provide a barrier between the outside environment and internal parenchyma, and are primary targets of respiratory pathogens. the respiratory epithelial cells constitutively activate vitamin d, and are capable of creating a microenvironment that has high levels of active form of the vitamin, resulting in the activation of downstream genes such as those for camp. moreover, viral rna increases the expression of 1α-hydroxylase, leading to increased activation of vitamin d and further increases in camp mrna (hansdottir et al., 2008) . hansdottir and colleagues (2010) have shown in an in vitro human tracheo-bronchial epithelial cell model for respiratory syncytial virus infection, that vitamin d attenuates inflammatory cytokine and chemokine response, while maintaining the antiviral activity. this local vitamin d-mediated anti-viral, anti-inflammatory immune response could result in decreased disease severity and morbidity from this common infection (hansdottir et al., 2010) . thus, vitamin insufficiency and notably, a seasonal decrease of vitamin d-dependent epithelial and leukocyte innate host defense could contribute to increased susceptibility to respiratory infections during 16. vitamin d and respiratory infections in infants and toddlers winter. a prospective descriptive study of outcomes associated with vitamin d deficiency and pneumonia reported 25(oh)d deficiency associated with increased mortality but not associated with levels of cathelicidin or beta-defensin (leow et al., 2011) . clinical trials are underway to assess camp expression as a biomarker for fetal-neonatal immune function following antenatal vitamin d supplementation (clinicaltrials.gov identifier: nct01126528) and in a separate trial for intensive care unit-associated lung failure, camp and beta-defensin concentrations will be evaluated as a secondary outcome following high-dose vitamin d regimen (clinicaltrials.gov identifier: nct01372995). while we limit our review to the role of innate immune antiviral functions to respiratory infections, vitamin d status has been associated with other prenatal and postnatal immunomodulatory effects, such as promoting peripheral tolerance by rendering antigen presenting dendritic cells tolerogenic and development of t-regulatory cells. dendritic and t-regulatory cells serve as pivotal links between innate and adaptive immunity, and play a key role in the protection against the inflammatory sequela of airway infections and in the protection against induction and expression of atopic disease (chambers and hawrylowicz, 2011; holt et al., 2008) . there is an association of wintertime peaks in respiratory infections especially in the higher latitudes to vitamin d status as the cutaneous synthesis of vitamin d is naturally blunted during that time of the year (cannell et al., 2006) . respiratory tract infections in the neonatal and pediatric populations are normally viral in origin with accompanying wheezing, pneumonia or bronchiolitis. the infections can be classified into urtis and lrtis with the urti a primary site of contact for inhaled agents, and lrtis as infections of the intra-thoracic airways and/or lung parenchyma with severe cases leading to bronchiolitis and pneumonia. the main etiological agents include human rhinovirus, rsv, human coronavirus, adenovirus, parainfluenza virus and influenza virus. cases of bronchiolitis associated with human rhinovirus (46-49%), rsv (11-27%), and parainfluenza viruses (5-13%) account for most of the outpatient sampling in infants with urtis and lrtis (camargo et al., 2011a) . viral infections including rhinovirus and rsv could lead to bronchiolitis and early episodic wheezing in infants (gern and busse, 2002) , symptoms which are commonly associated with the likelihood of developing reactive airway disease or asthma in early childhood (asher et al., 2006; litonjua, 2012; wu et al., 2008) . large cohort studies, however have demonstrated that many children who wheeze in early childhood during acute respiratory infections do not go on to develop asthma (camargo et al., 2011b; martinez et al., 1995; stein and martinez, 2004) . in addition, accumulating evidence implicates a background of atopy as a leading cause of asthma associated with airway inflammation from respiratory infections (holt et al., 2012) . nevertheless, asthma is a heterogeneous disease and since clinical diagnosis of asthma in children remains a challenge, epidemiological studies of children often focus on childhood wheezing; and in this chapter, we present selected epidemiological studies k.v. balan, u.s. babu, d.e. godar and m.s. calvo on vitamin d deficiency in children and associated respiratory infections and wheezing but not related to asthmatic conditions. circulating 25(oh)d level provides a distinct advantage to assess vitamin d status than selfreported dietary intake, and cord-blood 25(oh)d concentration is strongly associated with maternal concentration during pregnancy. in a birth cohort study of 922 children cord-blood levels of 25(oh)d had inverse associations with the risk of respiratory infection by three months of age (or: 1.00 for ≥75 nmol/l, 1.39 for 25-74 nmol/l, and 2.16 for <25 nmol/l). likewise, cord-blood 25(oh)d levels were inversely associated with risk of wheezing by 15 months, 3 years, and 5 years of age (all p<0.05) and no association to incident asthma by the age of 5 years. additional adjustment for potential confounders including seasons of birth did not materially change these results (camargo et al., 2011b) . a recent birth cohort study of 156 healthy neonates showed an association of vitamin d deficiency with increased risk of rsv lrtis in the first year of life. neonates born with 25(oh)d concentrations <50 nmol/l had a sixfold (95% ci=1.6-24.9; p=0.01) increased risk of rsv lrti in the first year of life compared with those with 25(oh)d concentrations ≥75 nmol/l (belderbos et al., 2011) . similarly, in a population based mother-child cohort study there was a trend of independent association between higher levels of maternal circulating 25(oh)d in pregnancy and decreased odds of lrtis in offspring (for cohort-and season-specific quartile q4 vs. q1, or: 0.67 (95% ci=0.50-0.90); test for trend, p=0.016). no association was found between 25(oh)d levels in pregnancy and risk of wheezing at age 1 year or 4 years, or asthma at age 4-6 years (morales et al., 2012) . nutritional rickets due in part to vitamin d deficiency is a major health problem in developing countries. it is associated with respiratory muscle weakness and increased risk of respiratory infections. the first association of sub-clinical nutritional rickets to respiratory infections was observed in a case-control trial among indian children (3-12 years) with multiple episodes of respiratory infections. administration of oral vitamin d, 60,000 iu/wk and 650 mg of calcium/d for 6 weeks decreased the incidence of respiratory infections in the test population (rehman, 1994) . similarly in a case-control study, 13-fold higher incidence of nutritional rickets was observed among toddlers (<5 years) with pneumonia than among controls (or=13.37; p<0.001) (muhe et al., 1997) . more recently, significant associations have been identified with non-rachitic vitamin d levels and respiratory tract infections suggesting that vitamin d insufficiency is enough to trigger respiratory infection rather than a secondary manifestation of acute deficiency typically leading to nutritional rickets. in a hospital-based case-control study of non-rachitic indian children age 2-60 months, serum 25(oh)d levels of <22 nmol/l had more than 10-fold higher odds of acquiring severe acute lrtis (or: 0.09; p<0.001) (wayse et al., 2004) , and in a similar study design in rural bangladesh, 25(oh)d levels in children (1-18 months) hospitalized with acute lower respiratory infections (alris) were significantly lower (29.1 nmol/l) than case matched controls (39.1 nmol/l). the unadjusted odds ratio of alris was halved for each 10 nmol/l increase in 25(oh)d (or=0.53; 95% ci=0.3, 0.96) (roth et al., 2010) . furthermore, in a neonatal case-control study of alris in turkey, mean serum level of 25(oh)d was 22.7±22.2 nmol/l compared to age-matched control levels, 40.6±33.6 nmol/l (p=0.011) and corresponding 25(oh)d levels in mothers of the study group were lower than those in the mothers of the control group (33.4±42 nmol/l and 57±42.3 nmol/l respectively; p=0.012). these findings suggest that newborns with subclinical vitamin d deficiency may have an increased risk of suffering from acute lower respiratory infection and the strong positive correlation between newborns and mothers 25(oh)d concentrations shows that adequate vitamin d supplementation of mothers should be emphasized during pregnancy (karatekin et al., 2009 ). in contrast, two case-control studies in canadian children did not reveal an association between vitamin d deficiency and respiratory infections as virtually all children consumed vitamin d fortified infant formula or supplements (roth et al., 2009 published data from randomized control clinical trials to evaluate the effects of vitamin d on reducing rtis in children are limited. despite mixed results because of study design, lack of measurement of 25(oh)d serum levels and poor compliance, four studies have shown potential for vitamin d intervention to help control respiratory tract infections in the adult population (aloia and li-ng, 2007; avenell et al., 2007; laaksi et al., 2007; li-ng et al., 2009) . we have presented what we believe is compelling evidence of a global problem of poor vitamin d status experienced in utero and perinatally; and even more critical, is the evidence showing the association of vitamin d deficiency during this dynamic period of development with increased morbidity and mortality risks from respiratory infections. worldwide recognition of this problem is growing and this awareness is stimulating changes in dietary guidelines (table 16 .1), as well as advice on safe sun exposure (godar et al., 2012) and strategies for national fortification policies (babu and calvo, 2010) . viral and bacterial pneumonia kills more children than any other illness, accounting for 19 per cent of all under five deaths worldwide (unicef, 2006) . according to the 2006 unicef/who report, an estimated 26% of neonatal deaths are caused by severe infections during the neonatal period, the majority of which are caused by pneumonia/sepsis. undernutriton, which includes vitamin d insufficiency/deficiency, has been implicated in 53% of all deaths among children under five (unicef, 2006) . if vitamin d intervention currently under study in the clinical trials described in this chapter is proven successful, then implementation of new fortification practices, revised guidelines for healthy sun exposure and public health programs for vitamin d supplementation of pregnant/lactating women and their infants may be effective strategies to aid in preventing neonates and children under five from developing respiratory infections. globally, there is potential to save more than a million young lives with preventive treatment, a compelling reason why the efficacy of optimizing vitamin d-mediated defense against respiratory pathogens in infants and children merits further study. the findings and conclusions presented in this review are those of the authors and do not necessarily represent the views, opinions or policies of the us food and drug administration. unexpected actions of vitamin d: new perspectives on the regulation of innate and adaptive immunity re: epidemic influenza and vitamin d institute of medicine (us) committee to review dietary reference intakes for vitamin d and calcium vitamin d and respiratory infections in infants and toddlers worldwide time trends in the prevalence of symptoms of asthma, allergic rhinoconjunctivitis, and eczema in childhood: isaac phases one and three repeat multicountry 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deficiency and supplementation during pregnancy vitamin d deficiency causes deficits in lung function and alters lung structure key: cord-286923-o4fj8kx0 authors: berhan, yifru title: what immunological and hormonal protective factors lower the risk of covid-19 related deaths in pregnant women? date: 2020-07-18 journal: j reprod immunol doi: 10.1016/j.jri.2020.103180 sha: doc_id: 286923 cord_uid: o4fj8kx0 despite anticipated increased risk of covid-19 and increased expression of the sars cov-2 receptor (ace2), the relatively low mortality of pregnant women with covid-19 has been an area of wonder. the immunological changes predominantly inclining to anti-inflammatory state, which is augmented by placental hormones’ immune modulating action, looks against with covid-19 inflammatory reaction leading to cytokine storm and multiple organ failure. unlike many other viral infections, the bilateral immune activation of covid-19 may preferentially make pregnant women at low risk. taking the physiological advantage of pregnant women, potential clinical trials are proposed. quite a large number of epidemiological and obstetrics related studies have addressed the cases of women with covid-19. however, to the best of the author's knowledge, little is done to explore the physiological internal milieu of pregnant women in relation to covid-19. this review provides an insight into how the hormonal and immunological changes in pregnancy potentially reduce sars-cov-2-mediated inflammatory response. coronavirus disease (covid19) was first recognized in late 2019 in wuhan/china as caused by severe acute respiratory syndrome corona virus (sars cov-2) and has become pandemic [1] . in due course, among several unprecedented events, the relatively low mortality of covid-19 in pregnant women has been an area of wonder. what is known before is that the immunological change during pregnancy inclining to the anti-inflammatory state is for the benefit of the fetus, but an increased risk for the mother to have many of the viral infections (predominantly in the respiratory system) and severity of malaria [2, 3] . interestingly, pregnant women can have as remission of symptoms of many of the autoimmune diseases as noted below [4, 5] . it looks that autoimmune diseases and covid-19 have something in common during pregnancy. previous studies have shown that pregnant women are at increased risk of morbidity and mortality due to many of the fatal viral infections, including hepatitis e virus, influenza a virus, sars cov, and mers cov [6, 7] . table 1 summarizes the comparative maternal mortality risks in different infection outbreaks over the past two decades [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] . the systematic review of 108 pregnant women from different countries has shown that severe infections were relatively uncommon and there was no maternal death as compared to the aforementioned viral infections [14] . report of the who-china joint mission has also concluded that severe disease due to sars cov-2 infection was uncommon among pregnant women [17] . as an unpublished data shows, the infection rate of covid-19 to pregnant women, however, is not different from the general population. so, multiple cases series reviews have demonstrated that pregnancy did not add risk to deterioration due to sars cov-2 infection [14, 19, 20] . the second largest cohort study has shown that 427 pregnant women (0.5% of estimated maternity across the uk) with confirmed sars-cov-2 infection were hospitalized in about one and half months, dominantly black and minor ethnicity with preexisting co-morbidities, overweight/obesity, and older maternal age [13] . in the same study, 40(9%) required critical care (the majority in the third trimester); 4(0.9%) required cardiopulmonary life support; 5(1.2%) died; and was concluded that most women do not have severe illness. the usa cohort study has shown an increased risk of hospitalization and intensive care unit admission (icu), but not death; out of 8207 pregnant women with covid-19, the proportion of death was 0.2% [18] . the big limitation of these two studies was that pregnancy related problems for hospitalization and icu care were not included in the reports. this is despite anticipated increased risk of covid-19 (taking their high vulnerability to viral infections) [2] , and increased expression of the sars cov-2 receptor (angiotensin converting enzyme/ace2) [21] . a recent review by liu and colleagues have also predicted as covid-19 may be altering the maternal immune responses, and affect the well-being of mothers and their babies [22] . hereunder, in depth review of the multisystem physiological changes in pregnancy as protective factor, which may show the window of acumen to search for a possible remedy for those who developed the disease of sars cov-2. therefore, the purpose of this review is primarily to give an insight on the physiological and immunological changes of pregnancy and shed light on the unfavorable nature of the internal milieu of the pregnant women to the covid-19 related inflammatory tissue damage and microthrombotic events and propose potential clinical trials. the spectrum of covid-19 is broad and not yet clearly defined. since sars cov-2 can infect a large array of respiratory and extra-respiratory tract cells, the severity and mortality risks were reported as being predominantly related to pneumonia, respiratory failure, acute respiratory distress syndrome (ards) and sepsis [23, 24] . in recently emerging reports, however, viral pneumonia is highly questioned; rather, thrombotic microangiopathy or atypical disseminated intravascular coagulation (dic) with increased risk of pulmonary vascular coagulation and thromboembolism are emphasized as major pathological disorders associated with covid-19 [25] [26] [27] . unlike other causes of ards, the typical features of ards with covid-19 leading to respiratory failure (relatively preserved lung compliance, high alveolar-arterial oxygen gradient, and diffuse pulmonary microthrombi) are also attributed to occlusion of the pulmonary microvasculature [28] . the previously thought interstitial pneumonia from lungs x-ray is reinterpreted as disseminated interstitial coagulation, primed by inflammation. postmortem examinations have also indicated the diffused microthrombi, which are more of fibrin deposits and mainly in the pulmonary microvascular system. further, unlike other causes of dic, modest thrombocytopenia, little change in fibrinogen level, prothrombin time and activated partial thromboplastin time are observed, but the d-dimer is exceptionally high in severely ill covid-19 patients [23, 24, 29] . one more, the absence of hemolysis indicators (like schistocytes) and low hemorrhagic disease, even in severe cases, are additional findings for the distinct nature of dic and for non-red blood cells source of the high lactate dehydrogenase (ldh) in covid-19 patients [24, 27, 30] . the pathological changes in the lungs in a state of ards, for instance, include diffused alveolar damage, hyaline membrane formation, extensive microvascular thrombosis and interstitial edema, which may progress to fibrosis among survivors of the acute insult [27, 31] . as a result, most of the deaths were reported to be due to diffused thrombotic microangiopathy and respiratory failure [25, 32] . the unregulated overproduction of proinflammatory chemokines and cytokines (interleukin-6/il-6 and tumor necrosis factor-alpha/tnf-α, in particular) are attributed to many of the severe and fatal complications of covid-19 (what is commonly described as "cytokine storm" with ards) [33, 34] . on top of mediating inflammation, the increased il-6 level in covid-19 patients is also attributed to initiating coagulation activation and thrombin generation by inducing tissue factor expression on mononuclear cells [27] . as discussed hereunder, accumulating evidence from other infections and autoimmune diseases shows that immune modulating hormones, cytokines and other anti-inflammatory endogenous ligands are determinant factors in reducing the severity of several diseases during pregnancy; which could also be the most plausible explanation for the less severity and mortality of covid-19 in pregnant women. pregnancy has a triphasic shift of immunological response: a proinflammatory in early stages of pregnancy, anti-inflammatory throughout the rest of pregnancy and proinflammatory in the peripartum and postpartum period [35] . the proinflammatory state is characterized by t-helper/th-1 and th-17 immunity dominance (hereafter th-1), resulting in overproduction of proinflammatory cytokines, including il-1β, il-6, il-8, il-12, tnf-α, chemotactic cytokines (interferon gamma/ifnγ, eotaxin) and growth factors. (ifnγ, il-1β, il-6, and il-12), which were attributed to the extensive lungs damage and high mortality [40, 41] . it is not clearly known why the th-2 immunity/anti-inflammatory cytokines were equally prominent in all investigated covid-19 cases. although the overall condition is a sort of cytokine release syndrome (crs), the concentration of proinflammatory cytokines such as il-6, tnf-α, il-1 and ip-10 was much higher among severe covid-19 patients [39, 42] . il-6 is thought to be responsible for increased capillary leakage, activation of complement and the coagulation cascade, partly leading to the development of the atypical dic [43, 44] . therefore, the parallel activation of the th-1 and th-2 immunity in covid-19 may not lead to a profound proinflammatory cytokine storm in pregnant women who already have dominant th-2 immunity. that is to mean, as noted below, the dominated anti-inflammatory state during pregnancy (the il-10 and placental hormones, in particular) may reduce the risk of covid-19 mediated cytokine storm and thrombotic microangiopathy. the markedly elevated il-10 level, starting from early pregnancy and throughout pregnancy, is a unique characteristic of normal pregnancy. the multitude sources of il-10, particularly at the placental-decidual interface (trophoblasts, uterine natural killer cells, monocytes, and tg cells), make it to be available in abundant amount [45] , which is a benefit for the dominance of the anti-inflammatory state of pregnancy. the implication is that the antiinflammatory and antifibrotic actions of il-10 in the lungs and other tissues by suppressing the th-1 immunity [46] is probably protective from covid-19. interestingly, while inhibiting the th-1 cells, il-10 enhances b cells survival and antibody production, which is beneficiary to balance the immune suppression and induction [47] . generally, there is a large body of evidence which showed that il-10 is a key cytokine with multifaceted actions during healthy pregnancy. the significantly lower level of il-10 in the placenta and decidua of women with missed abortion, recurrent spontaneous abortion, preterm birth, preeclampsia, and fetal growth restriction [46] may also suggest how potent it is in protecting the normal progress of pregnancy unless the other way round is considered (some other pathology compromising its secretion). several studies have also indicated the the deterioration of covid-19 patients is mainly due to overproduction of proinflammatory cytokines and activation of the coagulation pathway partly via protease activated receptors (principally par-1) and il-6 [51, 52] . this will lead to exaggerated inflammatory response and procoagulant-anticoagulant imbalance, which in turn results in a cascade of catastrophic events (extensive tissue damage, release of excess tissue thromboplastin, diffused microthrombosis, dic, and multiorgan failure). in pregnant women, however, this is not the case probably partly because of the physiological changes in the hematological system. among multiple actions of thrombin, there is a large body of data that has shown its involvement in the induction of systemic intravascular inflammation mediated through par-1 (by increasing the release of il-1β, il-6 and il-8, activation of endothelial and mast cells, and recruitment of monocytes), which is also ascribed for the pathogenesis of preeclampsia [53] [54] [55] . in non-pregnant covid-19 patients, the diffused inflammatory reaction already induced by the proinflammatory cytokines is a triggering factor in the over activation of par-1thrombin induced inflammation and defective anticoagulant system (ineffective j o u r n a l p r e -p r o o f antithrombin iii, tissue factor pathway inhibitor, and the protein c system) as already noted in other fibroproliferative inflammatory lung disease [51] . interestingly, in normal pregnancy, however, par-1 is undetectable after 12 weeks of gestation [56] . taken together, the suppression of par-1 expression and the domination of th-2 anti-inflammatory state during pregnancy may contribute to the relatively benign course of covid-19 in normal pregnancy. further, being the risk of dic in women with covid-19 is lower while pregnancy is a hypercoagulable state [57] , which is another evidence to deduce that the anti-inflammatory cytokines and placental hormones are strong in normal pregnancy. as noted earlier, progesterone is one of the anti-inflammatory hormones. it promotes the production of th-2 cytokines to protect the pregnancy [58] [59] [60] . the increased level of progesterone (mainly from the placenta) stimulates the synthesis of progesterone-induced binding factor (pibf) in lymphocytes [7] . the increased concentration of pibf in pregnancy promotes the differentiation of th-1 cells into th-2 cells, which results in augmented production of the aforementioned anti-inflammatory cytokines and progressive decline in th-1 secreted proinflammatory cytokines [7] . abnormally elevated ifn-γ and tnf-α (th-1 cytokines) can cause damage to the placenta and fetal tissue by activating the inflammatory reaction, macrophage, cytotoxic cell, and natural killer cell. progesterone also inhibits macrophage and natural killer cell activity, tolllike receptor (tlr-4) induced cytokine production and tnf-α, thereby exposing to bacterial infection and complications [61] , as the th-2 dominated immunity increases the risk of viral infection. in animal model with autoimmune encephalomyelitis, progesterone treatment has shown a significant reduction in disease severity and increases the level of il-10 [62] , which is another important indicator of its multiplied effect. therefore, the increased level of progesterone during pregnancy may complement to the physiological defense to covid-19. the immune modulating and anti-inflammatory actions of estradiol (e2) and estriol (e3) is also well noted during pregnancy. e3 (90% of all estrogens secreted during pregnancy) increases 1000 times during pregnancy from the only detectable level in non-pregnant women [63] . emphatic e3 increases the production of anti-inflammatory cytokines (il-10 and il-5) and reduces the production of proinflammatory cytokines (like tnf-α) [64] . the relatively increased e2 level (100 times) [63] and the extremely elevated e3 level during pregnancy promote th-2 responses and humoral immunity. whereas a reduction in e2 level results in augmented th-1 responses/proinflammatory cell-mediated immunity and bad pregnancy outcome [65, 66] . as a result, the anti-inflammatory action of estriol, in particular, is opening a new horizon of research to use it as an important therapeutic option for viral, autoimmune and neurodegenerative diseases outside pregnancy, including men and postmenopausal women [67] [68] [69] . in animal models, e3 had significantly reduced proinflammatory transcriptional activity, pulmonary immune cell recruitment, and pulmonary inflammation during influenza a virus infection [70] . a pilot trial of exogenous estriol administration to non-pregnant women with multiple sclerosis has resulted in 80% reduction in gadolinium-enhancing lesions from the pretreatment state within 3 months, which was correlated with the favorable shift in cytokine profiles [64, 71] . therefore, the th-2 immunity activation and anti-inflammatory actions of e2 and e3 are likely to contribute to reduce the proinflammatory cytokine storm and subsequent complications of covid-19, which need to be further explored with clinical trial. vitamin d is another important hormone, which has both immune modulation and antiinflammatory actions [72] , that can positively influence pregnancy outcome and response to acute and chronic inflammatory diseases during pregnancy. apart from a wide array of j o u r n a l p r e -p r o o f immune cell activation during pregnancy, the stimulating effect to th-2 cytokine production and the inhibition effect to th-1/th-17 cytokine release is a synchronized effect of vitamin d with progesterone and estriol [73, 74] . a few anecdotal evidences have shown the increased risk of severity and mortality among non-pregnant covid-19 patients when there is vitamin d deficiency in their serum (1, 25-dihydroxy vitamin d3 <10 mg/dl) [75] [76] [77] . as learnt from animal models and human trials, among many of the vitamin d innate and adaptive immune modulating actions, its inhibitory action to il-6 and tnf-α [71, 78] is implicated in the reduced risk of covid-19 in vitamin d sufficient individuals. vitamin d reduces the inflammatory and t cell stimulatory actions of macrophages through an il-10dependent mechanism [79] . other investigators also verified its effect in monocytes il-10 production (first and short lasting repression and long lasting induction action) [47] . furthermore, vitamin d is a potent suppressor of ifnγ-mediated macrophage activation [80] , which all these are likely to be protective of the covid-19 severity. till proved otherwise, the reduction of covid-19 severity in vitamin d sufficient individuals is an interesting observation and another milestone to consolidate the significance of antiinflammatory endogenous mediators in the amelioration of the covid-19 morbidity and mortality. this observation may have as well programmatic implication as the world is advocating "stay at home/lockdown" preventive measures, while physical distancing at outdoor is probably an appropriate decision. vitamin d deficiency is associated with many acute and chronic inflammatory diseases, including increased risk of acute respiratory tract infections, tumorigenesis, pulmonary tuberculosis, atherosclerosis, inflammatory bowel disease, and rheumatoid arthritis [81] [82] [83] [84] [85] [86] . what is special for pregnancy (specific to vitamin d) is again its additional production by the placenta. according to one study, the placenta and decidua (mainly from macrophages, uterine natural killer cells, b cells, t cells, dendritic cells) is the principal source of vitamin d outside the renal site [74, 87, 88] , probably to meet the high demand of it for the fetal physical growth in the state of deficiency. the lower level of il-10 and tgf-β in vitamin d deficient pregnant women is another evidence on its significance in upregulating effect of the anti-inflammatory cytokines [88] . another study has also demonstrated that the placenta, decidua, therefore, on top of its tolerogenic effect, the immune modulating action j o u r n a l p r e -p r o o f is as well towards infection prevention, which is probably an additional advantage for pregnant women to clear sars cov-2 before causing serious tissue damage. pregnancy is also an advantage to get temporary amelioration from several th-1 associated autoimmune diseases (including multiple sclerosis, rheumatoid arthritis, graves' disease, myasthenia gravis, psoriasis, uveitis) [6, 7] . almost all pregnant women with these kind of autoimmune diseases have exacerbation of symptoms early in pregnancy (while the th-1 immunity is dominant) and a remarkable remission during the second half of pregnancy. when the placental hormones and the dominant effect of the anti-inflammatory immune response is relieved during the peripartum and postpartum period, there will be a rebound effect of autoantibodies and flare up of the symptoms. the mechanism for temporary remission of many of the autoimmune disease symptoms is not exactly known; the dominant th-2 immunity and the collective effect of the antiinflammatory cytokines and hormones is the most probable explanation. despite serious concern for patients with autoimmune disease, taking their immune suppression and medications, at least 110 individuals (79% females) with rheumatoid arthritis and got infected with sars cov-2 (from six continents) were not as such at higher risk of mortality, probably as they were on anti-inflammatory medication; only 6(5%) persons died of covid-19 [89] . this small data and the remission of autoimmune disease symptoms during pregnancy may still underscore how important the anti-inflammatory state is to reduce the risk of covid-19. covid-19 has also some common characteristics with systemic sclerosis. in both conditions, the proinflammatory (th-1) and ant-inflammatory (the-2) cytokines are activated; neither statistically significant deterioration nor improvement was observed during pregnancy [90, 91] ; the profibrotic effect of il-4, il-6 and tgf-β looks counterbalanced by significantly increased il-10. the author surmises that pregnant women's risk of having severe covid-19 very early in gestation (before the th-2 immunity and placental hormones take control) and in the j o u r n a l p r e -p r o o f postpartum period may not be different from the non-pregnant population. given the limited data on this aspect, and the immunological and hormonal destabilization during postpartum period as transiting from pregnancy to non-pregnancy state, the severity of and mortality due to covid-19 may be higher than the pregnancy period. as exaggerated chemokine directed immunologic response can be diseases conditions in non-pregnant women (autoimmune disease, chronic inflammatory disease, allergic reaction, atherosclerosis, cancer, and the like), unilateral suppressed th-1 immunity during pregnancy is an advantage for the fetus's intrauterine survival and symptom free life of the mother from the majority of the autoimmune diseases and less severe disease of covid-19 in most of pregnant women. therefore, what looks in common for autoimmune disease and covid-19 is the less risk of severity during pregnancy, probably due to similar immune modulating action of the pregnancy. first of all, assessing the cytokine profile and determining the vitamin d level of pregnant women based on covid-19 illness severity is critically important to verify the postulated mechanisms. several of ongoing trials aimed to reverse the overactive cytokine response with exogenous immunomodulators. herein, proposed clinical trial is intended to treat covid-19 in its early stage with hormonal analogues and anticoagulants. the author postulates that as pregnancy develops a natural way of defense mechanism against covid-19, the prevention of severe complications of this disease can be sought by boosting the naturally existing protective hormones and cytokines. some authors recommended administering anticoagulant for critically ill patients with elevated d-dimer [92] . extending this recommendation to be even earlier for seriously symptomatic patient (with high grade fever and persistent dry cough) may have better outcomes. it is noted that a randomized clinical trial on covid-19 is planned with vitamin d [75] . on top of administering antibiotic and anti-inflammatory agents for all with high grade fever, the clinical trial arms the author recommending for non-pregnant covid-19 patients are as follows. world health organization, who timeline covid-19 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wuhan coronavirus disease 2019 (covid-19) pandemic and pregnancy plasma inflammatory cytokines and chemokines in severe acute respiratory syndrome (sars) mers-cov infection in humans is associated with a pro-inflammatory th1 and th17 cytokine profile cytokine-targeted therapy in severely ill covid-19 patients: options and cautions il-6 as a keystone cytokine in health and disease immunotherapeutic implications of il-6 blockade for cytokine storm interleukin-10: a multi-faceted agent of pregnancy the role of the anti-inflammatory cytokine interleukin-10 in tissue fibrosis primary effect of 1α,25(oh)₂d₃ on il-10 expression in monocytes is short-term down-regulation deficiency of decidual il-10 in first trimester missed abortion: a lack of correlation with the decidual immune cell profile interleukin-10 2849aa genotype protects against pre-eclampsia novel approaches for mechanistic understanding and predicting preeclampsia abnormal coagulation parameters are associated with poor prognosis in patients with novel coronavirus pneumonia proteinase activated receptors in fibroproliferative lung disease activation of protease-activated receptor (par)-1, par-2, and par-4 stimulates il-6, il-8, and prostaglandin e2 release from human respiratory epithelial cells activation of mast cells induced by agonists of proteinase-activated receptors under normal conditions and during acute inflammation in rats receptors of the par family as a link between blood coagulation and inflammation the pattern of expression of proteas-activated receptors (pars) during early trophoblastic development haemostatic changes in pregnancy role of hormone-controlled th1-and th2-type cytokines in successful pregnancy progesterone favors the development of human t helper cells producing th2-type cytokines and promotes both il-4 production and membrane cd30 expression in established th1 cell clones the immunological pregnancy protective effect of progesterone is manifested via controlling cytokine production toll-like receptor-4-mediated macrophage activation is differentially regulated by progesterone via the glucocorticoid and progesterone receptors progesterone treatment reduces disease severity and increases il-10 in experimental autoimmune encephalomyelitis multiple sclerosis 3; gender and multiple sclerosis 154-189 immune modulation in multiple sclerosis patients treated with the pregnancy hormone estriol the complex role of estrogens in inflammation sex hormones and the immune response in humans differential neuroprotective and anti-inflammatory effects of estrogen receptor (er) alpha and erbeta ligand treatment estriol treatment ameliorates disease in males with experimental autoimmune encephalomyelitis: implications for multiple sclerosis estriol ameliorates autoimmune demyelinating disease: implications for multiple sclerosis estriol reduces pulmonary immune cell recruitment and inflammation to protect female mice from severe influenza treatment of multiple sclerosis with the pregnancy hormone estriol vitamin d inhibits monocyte/macrophage proinflammatory cytokine production by targeting mapk phosphatase-1 vitamin d: a steroid hormone with progesterone-like activity 1 alpha, 25-dihydroxyvitamin d3 and 24,25-dihydroxyvitamin d3 in vitro synthesis by human decidua and placenta does vitamin d protect against covid-19? -medscape vitamin d supplementation could possibly improve clinical outcomes of patients infected with coronavirus-2019 (covid-19) vitamin d and inflammation: potential implications for severity of covid-19 vitamin d and innate and adaptive immunity 1,25-dihydroxyvitamin d3 curtails the inflammatory and t cell stimulatory capacity of macrophages through an il-10-dependent mechanism 25-dihydroxyvitamin d3 is a potent suppressor of interferon gamma-mediated macrophage activation acute respiratory tract infection and 25-hydroxyvitamin d concentration: a systematic review and meta-analysis the anti-inflammatory effects of vitamin d in tumorigenesis low serum 25-hydroxyvitamin d level: an independent risk factor for tuberculosis? vitamin d and cardiovascular disease: from atherosclerosis to myocardial infarction and stroke vitamin d in inflammatory bowel disease: from biology to clinical implications vitamin d as a principal factor in mediating rheumatoid arthritis-derived immune response immunological role of vitamin d at the maternal-fetal interface vitamin d effects on the immune system from periconception through pregnancy rheumatic disease and covid-19: initial data from the covid-19 global rheumatology alliance provider registries pregnancy in systemic sclerosis the immunopathogenesis of fibrosis in systemic sclerosis anticoagulant treatment is associated with decreased mortality in severe coronavirus disease key: cord-284760-i1lspg8i authors: bashandy, samir a. e.; ebaid, hossam; abdelmottaleb moussa, sherif a.; alhazza, ibrahim m.; hassan, iftekhar; alaamer, abdulaziz; al tamimi, jameel title: potential effects of the combination of nicotinamide, vitamin b2 and vitamin c on oxidative-mediated hepatotoxicity induced by thioacetamide date: 2018-02-14 journal: lipids health dis doi: 10.1186/s12944-018-0674-z sha: doc_id: 284760 cord_uid: i1lspg8i background: the liver disease is one of the most important traditional public health problems in egypt. oxidative stress is attributed to such pathological condition that further contributes to the initiation and progression of liver injury. in the present study, we have investigated if the strong antioxidant power of nicotinamide (na), vitamin b2 (vb2), and vitamin c (vc) can ameliorate taa-induced oxidative stress-mediated liver injury in the rats. methods: thirty-six albino rats were divided into six groups: control group; taa group (ip injection with taa at a dosage of 200 mg/kg three times a week for two months); taa + na group (rats administered with na at a dosage of 200 mg/kg daily besides taa as in the control); taa + vb2 group (rats administered with vitamin b2 at a dosage of 30 mg/kg daily besides injection with taa); taa + vc group (rats administered with vitamin c at a dosage of 200 mg/kg daily along with injection of taa). taa + na + vb + vc group (rats administered the with the three vitamins daily in taa pre-injected at the respective doses described above). results: treatment of rats with taa led to a significant elevation of aspartate aminotransferase (ast), alanine aminotransferase (alt), alkaline phosphatase (alp), lactate dehydrogenase (ldh), total bilirubin, cholesterol, triglycerides, low-density lipoprotein (ldl) and tumor necrosis factor-alpha (tnf-α) in the serum samples. moreover, malondialdehyde (mda), hydroxyproline and nitic oxide (no) were also significantly increased in the taa-treated rats, while reduced glutathione (gsh), superoxide dismutase (sod) and catalase (cat) were significantly compromised in the hepatic samples. rats administered with na, vb2, and vc as individually or in combination ameliorated the deleterious effects of taa that was confirmed by histopathology. however, the combination of the three vitamins was found more effective as compared to each of the vitamins. conclusion: our work demonstrates that na, vb2, and vc cross-talk with each other that act as a more potent biochemical chain of antioxidant defense against taa-induced toxicities in vivo. egypt has been a hot spring of academic research under tropical medicine programs. due to such medical problems, the confronting physicians have been facing the complications of hepatic fibrosis and cirrhosis because of schistosomiasis and chronic viral infections. it led many of the prominent hepatologists to establish clinical liver centers in entire egypt region [1] . four over three decades, many investigators have been trying to find efficient and long-lasting clinical solutions for liver diseases. thioacetamide (taa) is a thio-sulfur-containing compound, which has been frequently used in leather, motor fuel, textile, paper, food, and beverage industries since long [2] . administration of one dose of taa leads to acute hepatic toxicity, while chronic exposure causes hepatic cirrhosis and possible development of liver tumors. the metabolic activation of taa by cytochrome p450 generates taa-intermediates, and reactive oxygen species (ros) that can further covalently bind to biologically significant molecules and increase cellular oxidative stress, lipid peroxidation, and deplete glutathione [3] . nicotinamide (na), is a precursor of essential coenzymes for numerous reactions in the body [4] . although na is known to prevent or treat pellagra [5] , it has other pharmacological actions as an antioxidant [6] , and antinociceptive [7] . nicotinamide, the amide derivative of vitamin b3, has been shown to exhibit a number of anti-inflammatory properties including inhibition of inducible no synthase (inos) [8] , free radical scavenging [9] , suppression of mhc class ii expression [10] and intracellular adhesion molecule icam-1 expression on endothelial cells [11] . na is changed to nicotinamide adenine dinucleotide by the aid of enzymes. these cellular pathways are essential for energy metabolism and may directly influence normal physiology, as well as disease progression [12] . for example, na has been shown to protect against bleomycin-induced pulmonary fibrosis [13] , and doxorubicin-induced nephrotoxicity [14] . riboflavin (vb2) is the central component of the cofactors flavin adenine dinucleotide (fad). vb2 plays a key role in cellular function, growth, development and energy metabolism [15] . it is effective in preventing migraine [16] and reduces hepatocellular injury following liver ischemia through its role in lowering hepatic inducible nitric oxide synthase and nitric oxide [17] . vb2 can act against oxidative stress, especially lipid peroxidation and oxidative injury. it is reported that riboflavin protects the body against oxidative stress by glutathione redox cycling beside conversion of the reduced riboflavin to the oxidized form among other possible mechanisms [18, 19] . vitamin c (vc) is the most important radical scavenging antioxidant in extracellular fluids [20] vitamin c (ascorbic acid) is a six-carbon lactone is called an antioxidant because, by donating its electrons, it prevents other compounds from being oxidized [21] . vc has been reported to attenuate hepatic damage and can act synergistically with other vitamins in the management of oxidative stress [22] . vitamin c was reported to form a synergy with other agents to protect the liver. one of the obvious synergies is between vitamin c and vitamin e that ameliorated ethanol-induced hepatotoxicity via normalization of transaminases, lipid peroxidation [23] and endogenous antioxidants [24] . thus, this study aimed to investigate hepatoprotective activities of nicotinamide, vitamin b2, and vitamin c, separately or in combination, against thioacetamide-induced liver damage, hyperlipidemia and oxidative stress in rats. the hepatoprotective activity was assessed using liver function tests, lipid profile, hepatic oxidative stress parameters, inflammatory markers and hydroxyproline as hepatic fibrosis marker. taa, na, vitamin b2 and vitamin c were purchased from sigma-aldrich corporation (st louis, mo, usa). remaining all chemicals were of analytical grade from authentic companies of international repute. the study was performed on six weeks' old male albino rats weighing 120-150 g, obtained from the egyptian holding company for biological products and vaccines, cairo, egypt. the animals were kept in an environment with controlled temperature (25°c), humidity (45-55%), and photoperiod (12-h/12-h light/dark cycle). all the animals under study had free access to chow diet and water. all animal care protocols were by the research ethics committee, national research centre, egypt. the rats were sorted into six groups, each containing eight rats as follows: group i: control rats without any treatment. group ii: rats injected ip with taa at a dosage of 200 mg/kg [25] thrice a week for two months. group iii: rats administered with na at a dosage of 200 mg/kg [26] daily and injected with 200 mg/kg of taa ip thrice a week for two months. group iv: rats administered with vitamin b2 at a dosage of 30 mg/kg [27] daily and injected with 200 mg/kg of taa ip thrice a week for two months. group v: rats administered with vitamin c at a dosage of 200 mg/kg [28, 29] daily and injected with 200 mg/kg of taa ip thrice a week for two months. group vi: rats administered with all three of the previous vitamins daily and injected with 200 mg/kg of taa ip thrice a week for two months. the ratio of a multivitamin was performed as previously described [30] . blood samples were collected from each group by puncture of the retro-orbital venous sinus, into heparinized tubes under light ether anesthesia weekly. the blood was centrifuged at 1200×g for 10 min to separate plasma which was stored at − 40°c. after collection of the blood samples, the animals from all the groups were autopsied under light ether anesthesia. the liver was removed from its surrounding tissues, placed into tubes and washed with normal saline (cold) and kept at − 40°c. the liver tissues were homogenized in a cold potassium phosphate buffer (0.05 m, ph 7.4) and centrifuged at 3000 rpm for 10 min at 4°c. the resulting supernatant of tissue homogenate was used for determination of the oxidative stress parameters. serum ast, alt, alp, ldh, total bilirubin, total protein, cholesterol, triglycerides, ldl and hdl concentrations were determined calorimetrically using the commercial kits (salucea company, netherlands). moreover, hepatic mda, gsh, cat, sod and no were determined calorimetrically using kits manufactured by bio-diagnostic, egypt. plasma tnf-α and hepatic hydroxyproline were determined by enzyme-linked immunoassay by the kits from r&d systems (usa) and koma biotechnology (seoul, korea) respectively. at the end of the experiment, a portion of a liver from each of the sacrificed rat was fixed in 10% buffered formalin and processed for paraffin sectioning after dehydrating them in various concentrations of alcohol, cleared with xylol and embedded in paraffin blocks. sections of about 5 μm thickness were stained with hematoxylin and eosin (h&e) for histological study. data have been presented as mean ± s.e.m and analyzed by one-way anova followed by least significant difference (lsd) using spss software (version 20.0, spss inc., chicago, il). the mean values illustrated in table 1 showed a significant elevation of plasma ast, alt, alp, ldh and total bilirubin in rats treated with taa only, while total protein decreased compared to the control. these effects on liver function parameters associated with injection with taa were alleviated when the rats were also treated with na, vb2 or vc, with a significant decrease in the liver enzyme levels and bilirubin and an increase in total protein. administration of all three vitamins together had a more profound effect in mitigating the adverse parameters than when the rats were treated with just one of the vitamins. taa injection resulted in a significant increase in the plasma level of cholesterol, triglycerides, and ldl, while hdl decreased significantly (table 2) . treating the rats with taa and na, vb2 or vc, however, resulted in the changes in these parameters being reversed to some extent. once again, a greater degree of improvement was noticed when the three vitamins were combined. the data relating to hepatic oxidative stress markers are summarized in table 3 and show a significant decrease in hepatic gsh, cat, and sod in the taa group, but a marked increase in hepatic mda, no, hydroxyproline and plasma tnf-α. these changes were significantly reversed in rats treated with the three vitamins in combination. control hepatic tissue figure 1 shows the typical structure of the hepatic tissues with normal polygonal hepatocytes and normal blood sinusoids. histopathological examination of hepatic sections from taa rats revealed the presence of vacuolated hepatocytes with degenerated nuclei and irregular and damaged cell membranes. disturbed and dilated blood sinusoids were also clearly observed along with fibroblasts distributed extensively through the hepatic tissue of this group. moreover, mitotic figures were also noted in some hepatic sections (fig. 1 ). the sections from this group showed an increased number of irregular hepatocytes with degenerated nuclei. disturbed and narrowed blood sinusoids, frequently infiltrated with inflammatory cells, were also a prominent feature in the liver sections of these rats, along with fibroblasts extensively distributed through the hepatic tissue (fig. 1) . the general structure of the hepatic tissue in this group was markedly improved. hepatocytes with faint cytoplasm but with healthy nuclei were arranged in hepatic cords creating narrow blood sinusoids (fig. 1) . the effect of combining taa with treatment with na histological examination of different sections from rats of this group revealed that there was a marked improvement in the distribution of hepatocytes relative to the hepatic blood sinusoids. on the other hand, hepatocytes appeared with vesiculated nuclei showing partially degenerated chromatin materials. although there was an apparent improvement in the general hepatic architecture, many pathological signs could still be observed in the sections of this group. some hepatocytes appeared vacuolated, and the blood sinusoids were narrow and disturbed in comparison with those in the control sections (fig. 1 ). liver disease has been one of the traditionally major health issues in egypt for a long time. the primary causes of liver disease are schistosomiasis (from the 1950s until the 1980s) and hepatitis c virus (1990s). here, we used taa to induce an experimental model of liver damage to mimic the pathophysiological symptoms of acute human liver diseases. taa causes hepatic fibrosis through liver cell membrane injury, which in turn, causes a marked increase in enzymes levels. in the present study, taa caused a significant increase in alt, ast, alt, ldh and bilirubin levels versus to the control the ones. elevation of the activity of liver enzymes after taa administration indicates cellular leakage, loss of structural and functional integrity of the liver [31] . we have previously reported several natural products with antioxidant and anti-inflammatory properties in vivo studies with promising results [32] [33] [34] [35] . the present investigation has shown that rats treated with taa have increased hepatic nitric oxide (no) and plasma tnf-α. although no is an important signaling molecule; yet its excess production results in the formation of peroxynitrite which is a very invasive cellular oxidant [36] . it is interesting, therefore to report that both these parameters were effectively countered in the animals administered with na, vb2 or vc in the present study. lots of literature on anti-oxidative therapy and antioxidants have been proposed to prevent and treat liver diseases [37] highlighting the curative properties of antioxidants in such ailments. specifically, treatment of taa rats with na improved the activities of liver enzymes and the histopathological structure of the liver. earlier, we have reported that na exerts a hepatoprotective effect against a high-fat ethanol diet and acetaminopheninduced acute liver injury [38] . besides, it is documented that na benefits both dams and pups; hence it merits evaluation for preventing or treating preeclampsia complication in human pregnancies [39] . furthermore, na has been effective in ameliorating many oxidative stressinduced pathological conditions [40] . similarly, vc also normalized the increased activity of liver enzymes in the plasma samples confirming its hepatoprotective effects in the present investigation. studies have shown that this vitamin has hepato-protective properties due to its antioxidative properties, that gets better in synergy with other agents. the co-administration of ascorbic acid with alpha-tocopherol acetate and sodium selenate ameliorated ethanol-induced liver damage in rats [41] . the vitamin is believed to normalize the liver function parameters like alt, ast, ldh, alp, some endogenous antioxidants as well as blood hydroperoxide and malondialdehyde in the livers of carbon tetrachloride intoxicated rats [42, 43] . besides, it has shown restoration and reconstitution of the polyfunctional, long-lived t-cells in the diabetic rats [44] . furthermore, the vitamin is the most important hydrophilic antioxidant with high efficiency of free radical scavenging in vivo [45] . however, the mechanism involved appears to be ascorbyl radical reacting with other free radicals to stop their propagation [46] . it is documented that vb2 significantly improves serum and the histological parameters of hepatocellular damage and neutrophil infiltration following liver ischemia in mice [17] . recently, many studies have also demonstrated that irradiated riboflavin protects the cisplatin-induced oxidative stress-mediated hepatotoxicity and nephrotoxicity in rodent based studies [47] [48] [49] [50] . furthermore, vb2 and uv light together were able to reduce the titer of mers-cov in human plasma products to a non-detecting level suggesting that the combination may lower the risk of transfusion transmission of mers-cov [51] . in this study treatment of rats with the three vitamins in combination led to a more pronounced alleviation of the effects of the liver injury induced by taa. we have previously found that folic acid and melatonin as a combination was superior to using them individually regarding recovering hepatic function and structure [51] . in the present data, taa administration resulted in a significant reduction in the table 3 effect of nicotinamide, vitamin b2 and vitamin c on hepatic mda (nmol/mg), gsh (μmol/g tissue), catalase (u/g tissue), sod (u/g tissue), no (nmol/g,hydroxyproline (ug/g tissue) and plasma tnf-α (pg/ml) plasma levels of a total protein that might be indicative of injury in the hepatocytes and excessive destruction of proteins including antioxidant enzymes and cellular reducing powers including sh-protein bond production or alterations in rna sequences in the target tissues. an increase in alp activity and bilirubin level after taa treatment reflects the pathological change in the biliary flow in the animals. likewise, their suppression in the rats treated with na, vb2, and vc as combination suggests possible stabilization of the biliary dysfunction. furthermore, taa also enhanced the extent of lipid peroxidation, liver fibrosis and cirrhosis accompanied by the morphological and many other biochemical alterations resembling that of the human disease [52, 53] . therefore, it is logical to say that taa caused the cellular damage by inhibiting the activity of the antioxidant enzymes in the present study [54] . the combination of three vitamins significantly decreased liver hydroxyproline content in taa-treated rats, which may be due to a decline in the accumulation of fibrotic tissue in the liver. our findings are in accord with many earlier studies emphasizing the role of oxidative stress in the mechanisms of liver fibrosis and cirrhosis [55] . the antioxidant enzymes (sod and cat) as well as reducing power gsh were found significantly improved in the liver homogenates of the rats treated with taa followed by the three-vitamins combination as compared to the control. the improvement of all these parameters seems to restore the structural and functional integrity of the target organs in the animals [56] . hyperlipidaemia is a vascular risk factor associated with atherosclerosis, coronary artery diseases, cerebral vascular disease and peripheral disease. the present investigation showed that the three vitamin combination inhibits the increase in cholesterol, triglycerides and ldl levels in taa treated rats. however, the combination increased the hdl level. our study showed that taa toxicity stimulated hypercholesterolemia with hypertriglyceridemia. vc may hinder the development of atherosclerosis and prevent the onset of acute coronary events by several molecular mechanisms. the vitamin also helps in maintaining arterial wall integrity that can alter cholesterol metabolism by modulating the conversion of cholesterol into bile acids, while it affects plasma triglyceride levels via modulation by lipoprotein lipase activity [57] . the vitamin has fig. 2 showing putative mechanism of taa-toxicity amelioration by the proposed combination of the vitamins also been shown to protect hdl cholesterol from lipid oxidation. it, therefore, allows for reverse cholesterol transport involving the removal of unesterified cholesterol from extrahepatic cell membranes into esterified ones via lecithin: cholesterol acyltransferase [58] . apart from these, another vitamin taken under the present study, nicotinamide has been reported to decrease serum cholesterol, triglycerides and free fatty acids in the fasting rat [59] . moreover, na induced up-regulation of tumor necrosis factor-α (tnf-α) transcription and interleukin-6 (il-6). both the cytokines are with lipolytic properties, thereby increasing free fatty acid release [60] . all the three vitamins have an excellent antioxidant and anti-inflammatory properties. upon their co-administration in taa pre-treated rodents, they decreased the oxidative stress that further improved cellular structure and functionality. the diminished liver function markers and cholesterol, ldl and tnf-α concomitant with enhanced activity of antioxidant enzymes (sod and cat) and replenishment of the cellular reducing power (gsh) are vivid indicators of recovery of tissue damage. the improvement in all these parameters indicates that the cellular, molecular and structural damage incurred by taa were alleviated by the combination of the vitamins. as each vitamin has a different degree of antioxidant and anti-inflammatory properties, their respective combination gives a different level of outcome after the treatment. however, when all the vitamins were administered together, they showed a synergistic ameliorative effect against the taa-induced toxic insults in vivo (fig. 2 ). the present study entails the combination of na, vb2, and vc has stronger antioxidant and anti-inflammatory power as compared to the individual potential of the vitamins against taa-induced toxicity. the three vitamins exert the protective effects through their antioxidant, antifibrosis and anti-inflammatory properties that consequently restore the structure and functionality of the target organs. hence, anti-oxidative therapy mainly comprising of natural antioxidants represents a reasonable therapeutic approach for the prevention and treatment of oxidative stressmediated liver diseases. liver disease in egypt: hepatitis c superseded schistosomiasis as a result of iatrogenic and biological factors bioactive food as dietary interventions for liver and gastrointestinal disease rat hmg-coa reductase activation in thioacetamide-induced liver injury is related to an increased reactive oxygen species content a review of nicotinamide: treatment of skin diseases and potential side effects pellagra: dermatitis, dementia, and diarrhea effect of combined fenofibrate and nicotinamide on oxidative stress and inflammatory cytokines involved in cisplatininduced nephrotoxicity in rats antinociceptive and antiinflammatory activities of nicotinamide and its isomers in different experimental models nicotinamide prevents interleukin-1 effects on accumulated insulin release and nitric oxide production in rat islets of langerhans oxygen radicals generated by the enzyme xanthine oxidase lyse rat pancreatic islet cells in vitro nicotinamide and 3-aminobenzamide reduce interferon-gamma-induced class ii mhc (hla-dr and -dp) molecule expression on cultured humanendothelial cells and fibroblasts inhibitory effects of nicotinamide on intercellular adhesion molecule-1 expression on cultured human thyroid cells elevation of cellular nad levels by nicotinic acid and involvement of nicotinic acid phosphoribosyltransferase in human cells evaluation of the effects of nicotinamide on the bleomycin-induced pulmonary fibrosis in rat doxorubicin induced nephrotoxicity: protective effect of nicotinamide modern nutrition in health and disease effectiveness of riboflavin in pediatric migraine prevention riboflavin (vitamin b-2) reduces hepatocellular injury following liver ischaemia and reperfusion in mice riboflavin (vitamin b2) and oxidative stress: a review ameliorative effect of riboflavin on the cisplatin induced nephrotoxicity and hepatotoxicity under photoillumination influence of vitamin c supplementation on oxidative stress and neutrophil inflammatory response in acute and regular exercise vitamin c as an antioxidant: evaluation of its role in disease prevention combined protective effect of vitamins c and e on cadmium induced oxidative liver injury in rats the hepatoprotective effect of vitamin c and e on hepatotoxicity induced by ethanol in sprague dawley rats combined effects of vitamin c, vitamin e, and sodium selenate supplementation on absolute ethanolinduced injury in various organs of rats the preventive and therapeutic role of curcumin in liver cirrhosis nicotinamide supplementation protects gestational diabetic rats by reducing oxidative stress and enhancing immune responses riboflavin attenuates lipopolysaccharide-induced lung injury in rats oral administration of vitamin c and histidine attenuate cyclophosphamide-induced hemorrhagic cystitis in rats single dose intravenous thioacetamide administration as a model of acute liver damage in rats the undenatured whey protein enhanced wound healing in mice whey protein enhances normal inflammatory responses during cutaneous wound healing in diabetic rats zinc improves the immune function and the proliferation of lymphocytes in cadmium-treated rats antioxidant potential of spirulina platensis mitigates oxidative stress and reprotoxicity induced by sodium arsenite in male rats wound healing of different molecular weight of hyaluronan; in-vivo study impairment of active avoidance learning and sensory motor reflexes in mice offspring induced by perinatal acute toxic exposure to selenium pathophysiological basis for antioxidant therapy in chronic liver disease hepatoprotective effects of vitamin c and micronized vitamin c against paracetamol induced hepatotoxicity in rats: a comparative study nicotinamide benefits both mothers and pups in two contrasting mouse models of preeclampsia role of nicotinamide (vitamin b3) in acetaminophen-induced changes in rat liver: nicotinamide effect in acetaminophen-damged protective effects of ascorbic acid, dl-alpha-tocopherol acetate, and sodium selenate on ethanol-induced liver damage of rats role of zinc as an antioxidant and anti-inflammatory to relieve cadmium oxidative stress induced testicular damage in rats carbon tetrachloride-induced hepatotoxicity and nephrotoxicity in rats: protective role of vitamin c vitamin c supplementation reconstitutes polyfunctional t cells in streptozotocin-induced diabetic rats determination of ascorbic acid and dehydroascorbic acid in biological samples by high-performance liquid chromatography using subtraction methods: reliable reduction with tris[2-carboxyethyl]phosphine hydrochloride antioxidants: characterization, natural sources, extraction and analysis scleral cross-linking using riboflavin uva irradiation for the prevention of myopia progression in a guinea pig model: blocked axial extension and altered scleral microstructure inactivation of middle east respiratory syndrome coronavirus (mers-cov) in plasma products using a riboflavinbased and ultraviolet light-based photochemical treatment vitamin b2: a promising adjuvant in cisplatin based chemoradiotherapy by cellular redox management riboflavin ameliorates cisplatin induced toxicities under photoillumination folic acid and melatonin ameliorate carbon tetrachloride-induced hepatic injury, oxidative stress and inflammation in rats study of the effects of melatonin on experimentally induced hepatic fibrogenesis in rats reproducible production of thioacetamideinduced macronodular cirrhosis in the rat with nomortality hepatocytes are protected by herb phyllanthus niruri protein isolate against thioacetamide toxicity melatonin ameliorates carbon tetrachlorideinduced hepatic fibrogenesis in rats via inhibition of oxidative stress novel mechanisms of natural antioxidant compounds in biological systems: involvement of glutathione and glutathione-related enzymes regulatory role of vitamins e and c on extracellular matrix components of the vascular system vitamin c inhibits lipid oxidation in human hdl relationship of nicotinamide and nicotinic acid to hypolipidemia widespread effects of nicotinic acid on gene expression in insulin-sensitive tissues: implications for unwanted effects of nicotinic acid treatment tumor necrosis factor-alpha modulates human in vivo lipolysis the authors extend their appreciation to the deanship of scientific research at king saud university for funding the work through the research group project no. rg-1436-004. we declare at this moment the role of the deanship of scientific research at king saud university in the design of the study and collection, analysis, and interpretation of data and in writing the manuscript.availability of data and materials all data generated or analyzed during this study are included in this published article. authors' contributions sb prepared the introduction and conducted the animal care, analyzed the biochemical data, prepared the results, figures, and the oxidative stress tests. he designed this study, supervised the practical work and finalized the manuscript. sm revised the manuscript. ia provided the chemicals and contributed to the final revision. ih designed the mechanism diagramme and checked english grammar, text, organization, and typesetting of the paper. all authors read and approved the final manuscript.ethics approval and consent to participate the study was approved by ethical committee of zoology department, king saud university, riyadh. the authors declare that there is no any individual person's data in any form (including individual details, images or videos). the authors declare that they have no competing interests.• we accept pre-submission inquiries • our selector tool helps you to find the most relevant journal submit your next manuscript to biomed central and we will help you at every step: key: cord-352744-dd2rbsla authors: pagano, maria teresa; peruzzu, daniela; ruggieri, anna; ortona, elena; gagliardi, maria cristina title: vitamin d and sex differences in covid-19 date: 2020-09-30 journal: front endocrinol (lausanne) doi: 10.3389/fendo.2020.567824 sha: doc_id: 352744 cord_uid: dd2rbsla nan hypovitaminosis d is implicated in various inflammatory, infectious and autoimmune diseases and recent lines of evidence suggest that it may represent a risk factor also for the ongoing epidemic of coronavirus disease 2019 (covid-19) (1) (2) (3) . in fact, the outcome of covid-19 appears to be influenced by vitamin d status of populations (4, 5) . several studies have clearly shown that 1,25(oh)2 vitamin d(3) (vitamin d3, the active metabolite of vitamin d), besides its classical function in calcium dependent bone homeostasis, is actively involved in the regulation of innate and adaptive immune responses (6) . in particular, it plays a key role in the control of the cytokine storm, i.e., the sudden acute increase in circulating levels of different pro-inflammatory cytokines, induced in several inflammatory conditions and also in covid-19 (7) . this activity of vitamin d3 is carried out by inhibiting the production of the proinflammatory cytokines such as tumor necrosis factor-a (tnf-a) and interferon-g (ifn-g) but, also, by increasing the expression of the anti-inflammatory cytokine interleukin-10 (il-10). moreover, vitamin d3 enhances the production of antimicrobial peptides such as human cathelicidin, ll-37 and defensins in several infections (8) . a further important feature of vitamin d3 is its capacity to reduce the risk of viral infections maintaining the integrity of the epithelium by the upregulation of genes which encode proteins required for tight, gap and adherens junctions (6) . further studies will be necessary to clarify whether all these anti-microbial effects could also occur against sars-cov-2, assigning to vitamin d3 a protective role against covid-19. notably, vitamin d3 enhances the expression of human angiotensin-converting enzyme 2 (ace2), the functional receptor for sars-cov-2 (9, 10). ace2 plays a protective role in acute respiratory distress syndrome and higher levels of ace2 seem to be associated with better outcomes for lung diseases and, in particular, for covid-19 (11) (12) (13) . based on these considerations, in covid-19 the inter-individual variability in circulating levels of 25-hydroxyvitamin d (25(oh)d), the biomarker of vitamin d status could be involved in the different severity of pulmonary inflammation and viral pathogenicity among individuals (14) . supporting the important protective role of vitamin d3 in covid-19 outbreak, negative correlations between mean levels of vitamin d3 of european countries and the number of covid-19 cases were observed (1, 13) . moreover, the lethality rate increased with age and with chronic disease comorbidity, both of which are associated with decreased vitamin d3 levels (15) . to note, epidemiological data indicate that covid-19 has a significantly higher lethality in men than in women (ratios up to 3:1), suggesting the presence of sex-dependent biological factors underlying these differences in disease outcome (16, 17) . it is known that, in general, innate and acquired immune responses are more intense in females than in males (18) . this can provide women with a more effective defense to fight new and infective pathogens, favoring viral clearance. another significant explanation for sex differences in covid-19 lethality is the sex-dependent modulation of cellular receptors and co-receptors used by sars-cov-2 to enter human host cells. in particular, ace2 is encoded on x-chromosome, in sites commonly escaping the inactivation of one x-chromosome in mammalian xx cells (xci), and could therefore be overexpressed in women (19) . moreover, estrogen induces an increase of ace2 expression that, as reported above, could play a protective role in acute respiratory distress (11, 20) , whereas androgen can increase the expression and activation of transmembrane serine-protease 2, (tmprss2), that facilitates virus-cell membrane fusion, thus favoring the infection (21) . moreover, a large number of covid-19 patients exhibit severe cardiovascular damage and those with pre-existing cardiovascular diseases appear to have an increased risk of death (22) . to note, estrogen has known protective effects on the cardiovascular system mediated by estrogen receptors, resulting in the activation of endothelial nitric oxide synthase. moreover, estrogen modulates serum lipoprotein and triglyceride levels and influences the expression of coagulant and fibrinolytic proteins. these estrogen-mediated actions could represent a further reason for the sex-specific differences in the outcome of covid-19 (23, 24) . a further interesting point is represented by the potential differences in serum level of 25(oh)d among men and women. sanghera and co-workers (15) observed a significantly reduced level of 25(oh)d in both men and women with obesity that represents a further important risk factor for covid-19. in this study, 25(oh)d level remains consistently lower in obese men than in obese women (15) . on the contrary, in another study, mucogiuri and co-workers (25) stratifying the sample population according to sex and body mass index (bmi), found that 25(oh)d concentrations were significantly higher in males compared to females in all bmi classes and decreased along with the increase of bmi values. although these contrasting data seem to not assign to 25(oh)d a clear role in determining sex differences in obese covid-19 patients, we think that attention could be paid to 25(oh)d levels in the context of this comorbidity. interestingly, sex differences have been observed in the immunomodulatory and anti-inflammatory effects of vitamin d3 in some autoimmune diseases. in particular, a study of correale and co-workers (26) showed that vitamin d3 induces a stronger inhibition of the production of pro-inflammatory cytokines and a higher increase of anti-inflammatory cytokines in lymphocytes from multiple sclerosis female patients in comparison to those from male patients. interestingly, spanier and co-workers (27) suggested that vitamin d3 acts in an estrogen-dependent manner in controlling t regulatory cell differentiation. moreover, estrogen seems to increase the expression of the nuclear vitamin d receptor (vdr) gene in cd4+ t cells (28) and to decrease the expression of cyp24a1, the cytochrome p450 component of the 25-hydroxyvitamin d(3)-24hydroxylase enzyme which inactivates vitamin d3. in turn, vitamin d3 exerts tissue-specific effects on peripheral estrogen metabolism (29) . hence, the sex-related immunomodulatory effects of vitamin d3 suggest that it is possible to speculate that also in covid-19, vitamin d3 could play a role in the outcome and lethality. in conclusion, the outcome of covid-19 appears to be influenced by the interaction among genetic, hormonal and environmental factors. the low levels of 25(oh)d could represent a risk factor for development of disease. in particular, it is tempting to hypothesize that the synergy between vitamin d3 and estrogen could affect the sex differences in the outcome of patients with covid-19. however, further studies will be mandatory in order to investigate the efficacy of vitamin d3 supplements, in combination or not with estrogen agonists, as a valid adjuvant for prevention and/or treatment of this severe infectious disease. evidence that vitamin d supplementation could reduce risk of influenza and covid-19 infections and deaths perspective: vitamin d deficiency and covid-19 severity -plausibly linked by latitude, ethnicity, impacts on cytokines, ace2 and thrombosis supplementation with vitamin d in the covid-19 pandemic? vitamin-d and covid-19: do deficient risk a poorer outcome 25-hydroxyvitamin d concentrations are lower in patients with positive pcr for sars-cov-2 a review of the critical role of vitamin d in the functioning of the immune system and the clinical implications of vitamin d deficiency is a "cytokine storm" relevant to covid-19? vitamin d and respiratory infection in adults letter: does vitamin d have a potential role against covid-19? vitamin d alleviates lipopolysaccharide−induced acute lung injury via regulation of the renin −angiotensin system ace2 expression and sex disparity in covid-19 angiotensin-converting enzyme 2 in lung diseases the role of vitamin d in the prevention of coronavirus disease 2019 infection and mortality considerations for obesity, vitamin d, and physical activity amidst the covid-19 pandemic vitamin d status, gender differences, and cardiometabolic health disparities sex-bias in covid-19: a meta-analysis and review of sex differences in disease and immunity gender differences in patients with covid-19: a narrative review sex drives dimorphic immune responses to viral infections landscape of x chromosome inactivation across human tissues protective regulation of the ace2/ace gene expression by estrogen in human atrial tissue from elderly men commentary: testosterone, a key hormone in the context of covid-19 pandemic endothelial dysfunction in covid-19: a position paper of the esc working group for atherosclerosis and vascular biology, and the esc council of basic cardiovascular science protective effects of estrogen on the cardiovascular system sex and gender differences in myocardial hypertrophy and heart failure sex differences of vitamin d status across bmi classes: an observational prospective cohort study gender differences in 1,25 dihydroxyvitamin d3 immunomodulatory effects in multiple sclerosis patients and healthy subjects vitamin d and estrogen synergy in vdr-expressing cd4(+) t cells is essential to induce helios(+)foxp3(+)t cells and prevent autoimmune demyelinating disease effects of estrogen on circulating ''free'' and total 1,25-dihydroxyvitamin d and on the parathyroid-vitamin d axis in postmenopausal women 25-dihydroxyvitamin d3 exerts tissuespecific effects on estrogen and androgen metabolism key: cord-343122-lppdauei authors: ribeiro, helena; de santana, keila valente de souza; oliver, sofia lizarralde; rondó, patricia helen de carvalho; mendes, marcela moraes; charlton, karen; lanham-new, susan title: does vitamin d play a role in the management of covid-19 in brazil? date: 2020-05-22 journal: revista de saude publica doi: 10.11606/s1518-8787.2020054002545 sha: doc_id: 343122 cord_uid: lppdauei the study discusses the possible role of adequate vitamin d status in plasma or serum for preventing acute respiratory infections during the covid-19 pandemic. our arguments respond to an article, published in italy, that describes the high prevalence of hypovitaminosis d in older italian women and raises the possible preventive and therapeutic role of optimal vitamin d levels. based on literature review, we highlight the findings regarding the protective role of vitamin d for infectious diseases of the respiratory system. however, randomized controlled trials are currently lacking. adequate vitamin d status is obtained from sun exposure and foods rich in vitamin d. studies in brazil have shown that hypovitaminosis d is quite common in spite of high insolation. authors recommend ecological, epidemiological and randomized controlled trials studies to verify this hypothesis. on march 25, 2020, doctors isaia and medico a , from università degli studi of turin, italy, released study, still in pre-print form, based on literature review, titled possible preventive and therapeutic role of vitamin d in the management of the covid-19 pandemic. in the manuscript 1 , the authors relate hypovitaminosis d to the prevention and treatment of covid-19, in association with other essential preventive measures. according to the authors: sulla base di numerose evidenze scientifiche e di considerazioni epidemiologiche, sembra che il raggiungimento di adeguati livelli plasmatici di vitamina d sia necessario anzitutto per prevenire le numerose patologie croniche che possono ridurre l'aspettativa di vita nelle persone anziane, ma anche per determinare una maggiore resistenza all'infezione covid-19 che, sebbene con minore evidenza scientifica, può essere considerata verosimile. (isaia and medico, 2020, p.1) a reference studies show the role of optimal vitamin d levels in the prevention and control of severe respiratory infections. since the authors collaborate in an international research aimed to investigate vitamin d status in older women from four continents b , contributions to this topic are being made within the context of the covid-19 pandemic. the rationale is based on evidence of the potential protective role of vitamin d in several diseases. adequate vitamin d status can be obtained from adequate sun exposure and foods rich in vitamin d. recently, vitamin d deficiency has been considered a global and widespread health concern at all ages 2 . older people are the most prone to hypovitaminosis d due to (a) low sun exposure when homebound or institutionalized, (b) reduced skin capacity to convert dehydrocholesterol into cholecalciferol, (c) changes in appetite and diet predisposing suboptimal vitamin d intake accompanied by reduced gastrointestinal absorption, (d) polypharmacy including medications that interfere in vitamin absorption or metabolism and (e) impairment of renal function 3 . changes or deficiencies in the activation and control of vitamin d absorption result in organic disorders that may evolve to important pathologies such as rickets in children and osteomalacia or osteoporosis in adults [3] [4] [5] [6] . a body of analyses from epidemiological evidence shows an association between vitamin d deficiency and increased risk of diabetes, cardiovascular diseases, osteoporosis, osteoarthritis, alzheimer's/dementia, myopia, macular degeneration, multiple sclerosis and some types of cancer 7, 8 . however, the impact of vitamin d supplementation on these outcomes in randomized controlled trials (rct) has not been reported. researchers have been studying the protective potential of vitamin d against diseases and health-related problems for many years, but here we highlight the protective role of vitamin d for infectious diseases of the respiratory system. in their review, isaia and medico 1 cite the study of bischoff-ferrari 9 , in which reduced concentrations of 25 (oh)d increase the risk of osteoporosis in older adults, being also associated with tumors, cardiovascular diseases, chronic autoimmune respiratory diseases, diabetes mellitus, neurological diseases and hypertension. as highlighted by isaia and medico 1 , "these pathologies potentially cause higher mortality, especially if these patients are affected by covid-19" (p.2), but this has not yet been proven. experimental studies using cell lines and mice have been conducted to elucidate the pulmonary activation of vitamin d3 and its preventive effect against interstitial pneumonia 10 . a based on numerous scientific evidences and epidemiological considerations, it seems that the achievement of adequate plasma levels of vitamin d is necessary first of all to prevent the numerous chronic pathologies that can reduce life expectancy in elderly, but also to determine a greater resistance to covidcovid-19 infection which, although with less scientific evidence, can be considered similar. ( findings suggest that vitamin d is activated in the lungs and that its dietary intake can prevent interstitial pneumonia by suppressing pulmonary fibrosis. another study 11 found that vitamin d injected into veins of rats, in pharmacological doses, relieved acute lung injury induced by lipopolysaccharide (lps). sabetta et al. 12 hypothesize that supplementation with vitamin d, to increase concentrations in the general population, above 38 ng/ml, would result in significant health benefit, by reducing the burden of viral infections of the respiratory tract in healthy adults living in temperate climates. however, this is based solely on speculation over the results of animal testing. isaia and medico 1 , based on these and other studies, address hypovitaminosis d and the epidemiology of covid-19 that has been affecting italy. they argue that italy is a country with a high proportion of older people, and that 76% of older italian women show vitamin d deficiency, without significant regional differences 13 . nevertheless, dr. isaia informed: "i have to underline that it is not a scientific paper, but only a literature review and an invitation to reach normal levels of vitamin d in ageing population, and in particular in coronavirus patients" (isaia, march 28, 2020, personal communication to these authors). published a note c highlighting that no indication for vitamin d supplementation was approved for effects other than bone health. in this note, they mention an article of the italian newspaper la reppublica, regarding a study conducted at turin university, which suggested that vitamin d could act in the prevention and treatment of covid-19. without mentioning the author's name, the note informs that this study has not been published in a scientific journal and that relevant data were not cited, including the number and age of participants and their 25 (oh) d levels. we believe this debate is based mainly on news of a non-scientific periodical and gained importance in social media, erroneously motivating self-administration of high doses of vitamin d. meanwhile, the brazilian president announced that vitamin d would be exempt of import tax as a measure to combat coronavirus. ergocalciferol (d 2 ) and cholecalciferol (d 3 ) are among the most important compounds that make up vitamin d. ergocalciferol or vitamin d 2 results from ultraviolet irradiation of sunlight on ergosterol 5 . pre-vitamin d 3 or cholecalciferol originates from a photochemical cleavage suffered by the cutaneous precursor of vitamin d, 7-dehydrocholesterol, when exposed to ultraviolet radiation 5, 14 . currently, there is no universal consensus on the optimal concentrations for plasma/serum 25-hydroxyvitamin d [25 (oh) d]. in the usa, vitamin d deficiency is defined as a plasma/serum 25 (oh) d status below 12 ng/ml (30 nmol/l) and insufficiency of 25 (oh) d status below 20 ng/ml (50nmol/l) 15 . in the uk, vitamin d deficiency is defined as a plasma/serum 25 (oh) d status below 10 ng/ml (25 nmol/l) 16 . cannel et al. 17 suggest 50 ng/ml is protective against viral respiratory infections, particularly in obese, older population, and those with dark skin. this finding, however, is not based on the results of a vitamin d rct in humans. dancer et al. 18 referred that patients with, and at risk of, acute respiratory distress syndrome, are highly likely to be deficient in vitamin d, based on evidence from human, murine and vitro experimental studies. ultraviolet b (uvb) radiation is the main source of the vitamin, providing around 80%. foods such as salmon and other oily fish, cod liver oil, egg yolk, milk and sun-dried mushrooms are natural sources of vitamin d. vitamin d supplementation and fortified foods such as butter and milk are widely used in countries at high latitude with long winters such as the usa. this is not the case in brazil. the time of year, latitude, skin color, age and use of sunscreen influence skin production 19 exposure to chemical products and microparticles, dispersed in the urban atmosphere, and tobacco smoke can disturb biochemical pathways and cause harmful consequences, such as vitamin d deficiency 21 . these factors are directly or indirectly implicated in the interruption of the endocrine system of vitamin d and in the decrease in serum levels of two main metabolites: calcifediol and calcitriol 21 . while the shade of trees allows sufficient transmission of uvb for vitamin synthesis, that of buildings and glass windows attenuates biologically significant wavelengths 22 . the time spent in outdoor activities by the population is directly and indirectly related to the existence of green areas, levels of air pollution, safety, and urban mobility. behavioral and cultural factors that influence the way of life can also reduce the ability to synthetize vitamin d by sunlight exposure. people with long working hours indoors and ethnic minority groups with formal requirement for heavy and covered clothing style have reduced capacity to synthesize vitamin d from uvb radiation 23, 24 . darker skinned ethnic groups are the most affected by the lack of uvb availability for the production of vitamin d by the skin 24 . with the exception of countries located at high latitudes, most individuals would obtain sufficient levels of vitamin d through sunlight exposure. however, the prevalence of vitamin d deficiency has also been reported in low latitude regions. in brazil, a study conducted in the city of são paulo found that 72% of institutionalized older adults and 43.8% of older people attending outpatient clinics showed lower levels of vitamin d 3 than recommended, contradicting the inference that in brazil the population is vitamin d-replete due to the high degree of insolation 3 . results of our study on vitamin d levels, in araraquara, sp, called morada do sol (house of the sun), with 101 community-dwelling healthy women aged 35 years or older, show that 15.8% and 1% had vitamin d insufficiency and deficiency, respectively. however, 25% of brown women had insufficiency, according to iom guidelines 15 , which is relevant to many brazilians. higher prevalence of vitamin d insufficiency was also found in women who worked in health and aesthetics services. this shows that even in tropical climates, a person's occupation may influence sun exposure and vitamin d concentrations. in our study, vitamin d levels were also inversely correlated with body mass index and waist circumference. obesity is linked to vitamin d insufficiency because it hinders the bioavailability of vitamin d 25 and can lead to health complications, such as the development of some types of diabetes. many factors worsen vulnerability of populations to viral diseases, such as comorbidities that might be associated with vitamin d deficiency. comorbidities have also been associated with higher risk of hospitalization and deaths among those infected by covid-19, increasing the demand for beds and intensive care units, at a time of shortage. hypovitaminosis d constitutes an additional risk to respiratory tract infections and to the response of the immune system among the brazilian population, despite high insolation, even in winter. further studies are urgently needed to investigate whether vitamin d status or supplementation might decrease severity of covid-19, particularly vitamin d randomized controlled trials. regular sunlight exposure is a preventive measure against vitamin d deficiency and can prevent diseases related to it. the urban population, especially the older one, tends to be less exposed to sunlight, due to many factors 24 . thus, people must achieve and maintain adequate serum 25 (0h) d levels in a period of social distancing and self-isolation. this might be obtained through lifestyle strategies, and a healthy balanced diet. considering the pandemic risk, the who and health authorities' recommendations for staying at home must be followed. for those who do not live in houses with gardens, sunlight exposure can be obtained from open windows or balconies. only if that is not possible, should an oral vitamin d supplement be considered at sacn/iom recommended doses to maintain adequate vitamin d levels for general good health. we strongly advise against high vitamin d supplements (e.g. 10,000iu per day) being currently recommended 26 . adequate vitamin d status may play a role in prevention and management of respiratory tract infections, which might include the covid-19 pandemic, especially among the older population and health professionals worldwide. we highly recommend ecological, epidemiological and rct studies to verify this hypothesis. university of turin vitamin d: the "sunshine" vitamin prevalence of vitamin d deficiency, insufficiency and secondary hyperparathyroidism in the elderly inpatients and living in the community of the city of são paulo vitamin d deficiency: a global perspective pesq bras odontoped clin integr the vitamin d deficiency pandemic: approaches for diagnosis, treatment and prevention the risks and benefits of sun exposure the 2011 report on dietary reference intakes for calcium and vitamin d from the institute of medicine: what clinicians need to know vitamin d supplementation and musculoskeletal health pulmonary activation of vitamin d3 and preventive effect against interstitial pneumonia vitamin d alleviates lipopolysaccharideinduced acute lung injury via regulation of the renin-angiotensin system serum 25-hydroxyvitamin d and the incidence of acute viral respiratory tract infections in healthy adults prevalence of hypovitaminosis d in elderly women in italy: clinical consequences and risk factors the importance of vitamin d levels in autoimmune diseases committee to review dietary reference intakes for vitamin d and calcium vitamin d in the management of covid-19 in brazil ribeiro h epidemic influenza and vitamin d vitamin d deficiency contributes directly to the acute respiratory distress syndrome (ards) influence of season and latitude on the cutaneous synthesis of vitamin d3: exposure to winter sunlight in boston and edmonton will not promote vitamin d3 synthesis in human skin laboratory confirmation of the effect of occupational sun exposure on serum 25-hydroxyvitamin d concentration air pollution, environmental chemicals, and smoking may trigger vitamin d deficiency: evidence and potential mechanisms vitamin d effective ultraviolet wavelengths due to scattering in shade environmental determinants of previtamin d synthesis in the united arab emirates impact of high latitude, urban living and ethnicity on 25-hydroxyvitamin d status: a need for multidisciplinary action? decreased bioavailability of vitamin d in obesity evidence that vitamin d supplementation could reduce risk of influenza and covid-19 infections and deaths award received in 2018. capes phd scholarship for kvss. capes pnpd scholarship for slo. cnpq productivity grant 1a for hr key: cord-320959-sgdqhtns authors: lee, hanjun title: vitamin e acetate as linactant in the pathophysiology of evali date: 2020-08-12 journal: med hypotheses doi: 10.1016/j.mehy.2020.110182 sha: doc_id: 320959 cord_uid: sgdqhtns the recent identification of vitamin e acetate as one of the causal agents for the e-cigarette, or vaping, product use associated lung injury (evali) is a major milestone. in membrane biophysics, vitamin e is a linactant and a potent modulator of lateral phase separation that effectively reduces the line tension at the two-dimensional phase boundaries and thereby exponentially increases the surface viscosity of the pulmonary surfactant. disrupted dynamics of respiratory compression-expansion cycling may result in an extensive hypoxemia, leading to an acute respiratory distress entailing the formation of intraalveolar lipid-laden macrophages. supplementation of pulmonary surfactants which retain moderate level of cholesterol and controlled hypothermia for patients are recommended when the hypothesis that the line-active property of the vitamin derivative drives the pathogenesis of evali holds. effectively reduces the line tension at the two-dimensional phase boundaries and thereby exponentially increases the surface viscosity of the pulmonary surfactant. disrupted dynamics of respiratory compression-expansion cycling may result in an extensive hypoxemia, leading to an acute respiratory distress entailing the formation of intraalveolar lipid-laden macrophages. supplementation of pulmonary surfactants which retain moderate level of cholesterol and 10 controlled hypothermia for patients are recommended when the hypothesis that the line-active property of the vitamin derivative drives the pathogenesis of evali holds. as of january 14, 2020, there were 2,668 reported hospitalized cases of e-cigarette, or vaping, product use associated lung injury (evali) in the united states [1] . patients with evali typically exhibit respiratory symptoms, such as dyspnea and tachypnea, and often require the 5 receipt of supplemental oxygen due to progressive hypoxemia [2, 3] . computed tomography (ct) scans of the chest of these patients mostly display diffuse ground-glass opacity, a non-specific sign characteristic of lung injury that is often indistinguishable from those induced by viral infections [4] . extensive investigation into evali has revealed an emerging link between the disease and tetrahydrocannabinol (thc). reportedly, as many as 82% of patients with evali 10 used thc-containing e-cigarettes, while those who solely used nicotine-containing products accounted for a mere 14% of all cases [1] . correspondingly, on october 4, 2019, the food and drug administration issued a public warning against thc-containing vaping products, and the rate of emergency department (ed) visits due to evali has significantly declined since then [5] . the pathophysiology and the definitive cause of evali are yet to be established. initial efforts 15 to elucidate the pathophysiology of the disease have mainly focused on its association with thc. 4 providers still mostly rely on a diagnosis of exclusion when a patient with a history of thccontaining vaping product usage exhibits severe respiratory symptoms indicative of evali [3] . since the epidemic of evali has already reached its post-peak period and is expected to enter a post-epidemic one in a near future [5] , thanks to global efforts to strengthen regulations against 5 e-cigarettes, it is likely that we might not be able to fully characterize the disease before the epidemic is finally over. nonetheless, for thousands of hospitalized patients who still suffer from the disorder and for the deceased who died without knowing what they were exactly dying from, the pathophysiological characterization of the disease should be continued and recent breakthroughs in the field are tremendously supporting us. 10 recently, investigators at the centers for disease control and prevention (cdc) identified vitamin e acetate, a chemical widely utilized as a diluent for thc-containing vaping fluids, as one of the potential causal agents of evali [12] . among 51 submitted samples of bronchoalveolar lavage (bal) fluid from patients, 48 samples contained high content of vitamin e acetate exceeding 2.32 nm, while none was observed in those of healthy e-cigarette users 15 without evali. primary toxicants other than vitamin e acetate were nearly absent in bal fluid samples from patients, indicating a strong association of vitamin e acetate in the pathology. in a field predominated by confusion, this discovery sets an important milestone. vitamin e has long been thought of as an antioxidant dwelling in the lipid bilayer. in fact, the discovery of the vitamin itself has come from reports of fetal resorption in murine models which were depleted of the vitamin [13] . the lethality of vitamin e deficiency was later attributed to 5 the lack of its antioxidative capacities, and it is now well-established that the vitamin is required for the protection of polyunsaturated fatty acids from being unwantedly oxidized [14] . however, vitamin e acetate, given the additional ester moiety, is deprived of the antioxidative property and is markedly more thermostable. furthermore, its affinity to α-tocopherol transfer protein (αttp) is ~50-fold lower than that of the natural stereoisomer of vitamin e [15] , indicating the 10 significance of an extensive water bridge between the hydroxyl group and residues tyr117, ser136, and ser140 in the binding of the vitamin to αttp [16] . despite αttp often being recognized as a hepatocyte-specific protein which presents vitamin e from endosomal compartments to the plasma membrane for secretion [17] , it is also expressed in the lung where it non-canonically increases the level of vitamin e upon hypercapnia [18] . due to these significant 15 differences between vitamin e and vitamin e acetate, it is important to clarify whether the lung injury observed in patients with evali is induced solely by the esterified derivative of the vitamin. unfortunately, the distinguishment between the two compounds has largely been neglected in the field of evali, and the scarcity of information on the esterified derivative of the vitamin has forced many investigators to rely on reported biochemical properties of 20 unmodified vitamin e in elucidating the pathophysiology of evali. unlike those administered via dietary uptake [19] , wherein the compound is readily hydrolyzed by cellular esterases, including pancreatic carboxyl ester hydrolase and cholesteryl ester hydrolase [20, 21] , inhaled vitamin e acetate does not undergo esterase-mediated hydrolysis in the time scale of several hours [22, 23] . this indicates that most of the inhaled vitamin e acetate would remain unhydrolyzed in the lung of e-cigarette users even until the next vaping session in a typical setting. this is analogous to those observations made in skin, wherein the hydrolysis rate of the esterified derivative was measured as mere 5% [24] . the mechanistic detail on why 5 inhaled vitamin e acetate is resistant to esterase-mediated hydrolysis, however, is poorly understood. despite the remaining controversy on which of these compounds is responsible for the pathogenesis of evali, there is ample amount of evidence to rule out the antioxidative property of vitamin e as its driving force. antioxidative activities have long been recognized as a 10 protective mechanism against injury in respiratory disorders. indeed, pulmonary surfactants contain significant amounts of superoxide dismutase and catalase activities, which act to scavenge extracellular reactive oxygen species, such as hydrogen peroxide, within the pulmonary system [25] . similarly, type ii alveolar pneumocytes secrete vitamin e alongside pulmonary surfactants to protect the respiratory system against inhaled oxidants [26, 27] . however, it is 15 worth to note that the protective effect of vitamin e in the pulmonary system is not solely due to its antioxidative property. indeed, the transcriptional activation of αttp, which increases the level of vitamin e in the pulmonary system, protects against ventilator-induced lung injury in murine models without affecting antioxidant response signaling, such as those dependent on nuclear factor erythroid 2-related factor 2 (nrf2) [18] . 20 recent investigations on the biological action of the vitamin have raised an emerging appreciation of its non-antioxidative properties [28, 29] . although it remains a matter of controversy whether non-antioxidative properties of the vitamin can be strictly discriminated from its antioxidative property [30] , thorough examination of the effects of vitamin e other than antioxidation in this poorly characterized respiratory disorder remains valuable. in this regard, herein i discuss several possible mechanisms by which vitamin e acetate in vaping fluids may drive the pathogenesis of evali. as the biochemical properties of the vitamin derivative have been insufficiently characterized, i focus on those of an unmodified vitamin. currently, there are 5 five established non-antioxidative properties of vitamin e in the biological system: i) its ability to induce gel-liquid crystalline phase transition, ii) its active deposition in the lipid droplet of macrophages, iii) its modulation of the antidiabetic cascade involving diacylglycerol kinase (dgk) and protein kinase c (pkc), iv) its activation of the xenobiotic-sensing pregnane x receptor (pxr) signaling, and v) its ability to modulate lateral phase separation. in each section, 10 i discuss possible ways by which these properties may contribute to the pathophysiology of evali and whether these properties are expected to be shared by vitamin e acetate. at last, i argue that the line-active property of the vitamin deserves academic attention. although toxic byproducts of heating vitamin e acetate have recently garnered considerable interest [31] , i instead focus on the biological action of the vitamin derivative itself, as there is yet lacking 15 amount of evidence that pinpoints toxic byproducts as the pathological driving force for evali. indeed, lanzarotta and colleagues have recently shown that the majority of vaporized vitamin e acetate exist either as an equimolar complex with thc or as a dimer [32] . 20 among the five non-antioxidative properties of vitamin e, investigators from the lung injury response laboratory working group have focused on its peculiar ability to induce gel (l β ) to liquid crystalline (l c ) phase transition in model saturated phosphatidylcholine bilayers [12] (l in the notation stands for lamellar). this property of the vitamin is believed to be the consequence 8 of its structural deviance from phospholipids. as the structure of vitamin e greatly differs from a typical phospholipid, especially in its rigid chromane double ring, the vitamin greatly perturbs the packing of phospholipids within the l β phase, resulting in a facilitated gel-liquid crystalline phase transition ( fig. 1 ) [33] . for instance, the addition of either vitamin e or vitamin e acetate 5 in molar ratios as high as 16 mol% in cholesterol-free model dimyristoylphosphatidylcholine (dmpc) membranes lowers the critical temperature required for gel-liquid crystalline phase transition for ~1.2 k [33, 34] . however, since cholesterol, a major constituent of biological membranes, also exhibits profound structural deviance from a typical phospholipid, it also facilitates gel-liquid crystalline phase transition in a similar manner. compared to free 10 cholesterol, vitamin e acetate is 1.5 times more potent in modulating the phase behavior of the lipid bilayer. as a consequence, one possible mechanism by which vitamin e acetate intoxication may lead to a fatal lung injury is its induction of liquid crystalline phase in pulmonary surfactants, which would likely influence the respiratory compression-expansion cycling. 15 a major downfall of blount and his colleagues' hypothesis is the abundance of free cholesterol in human pulmonary surfactants. indeed, free cholesterol level in bal fluids were measured as ~2.6 mm in murine models of pulmonary alveolar proteinosis (pap) [35] , while the level of vitamin e acetate observed in patients with evali, who occasionally feature signs of pap [36] , was in nanomolar range [12] . in contrast, the decrease in the critical temperature induced by the 20 addition of vitamin e acetate was of roughly the same orders of magnitude compared to that of free cholesterol. this indicates that the overall contribution of vitamin e acetate in the modulation of phase behavior is at least three orders of magnitude smaller compared to that of endogenously available free cholesterol. furthermore, the existence of cholesterol in human pulmonary surfactants is known to completely abrogate gel-liquid crystalline phase transition [37] . in explanation, the driving force for gel-liquid crystalline phase transition induced by vitamin e acetate in model saturated phosphatidylcholine bilayers has been its perturbation of phospholipid packing by structural deviance. the abundance of free cholesterol, of which 5 structure is as rigid as the head portion of the vitamin, in biological membranes offsets the structural deviance of vitamin e in lipid bilayers, resulting in an inability to induce gel-liquid crystalline phase transition (fig. 1) . indeed, the observation of gel-liquid crystalline phase transition has been limited to the cholesterol-free model saturated phosphatidylcholine bilayers [33, 34] and the membrane of mycoplasma laidlawii, which is depleted of cholesterol and is 10 enriched with saturated fatty acids [38] . accounting for the rationale behind the selection of mycoplasma laidlawii as the model system for investigating gel-liquid crystalline phase transition, steim and colleagues concisely stated, "because cholesterol interferes, to detect a phase change above the ice point in a membrane, an organism containing rather saturated fatty acids but little or no cholesterol must be chosen" [38] . 15 another important characteristic of vitamin e acetate in the biological system is its deposition in lipid droplets [39, 40] , and many investigators have especially focused on the observation of intraalveolar lipid-laden macrophages as it has been proven to be one of the most prominent 20 features of lung biopsies from patients with evali [41] . indeed, intraalveolar lipid-laden macrophages were also evident in a murine model of vitamin e acetate inhalation (daily inhalation of 77.3-167.5 μg vitamin e acetate per gram of body weight, two weeks of exposure), of which effect was largely absent in mice inhaled a mixture of propylene glycol and vegetable glycerin [42] . intriguingly, when a single dose of vitamin e acetate (inhalation of 0.1 μg vitamin e acetate per gram of body weight) was inhaled into the lipopolysaccharide-treated lungs of murine models, the substance greatly attenuated the inflammatory response, despite being 3-fold less potent than vitamin e [23]. this indicates that it is the excessive accumulation 5 of vitamin e acetate, rather than its transient exposure, which is responsible for the pathogenesis of evali. although it is tempting to speculate that intraalveolar lipid-laden macrophages observed are merely the consequence of excessive deposition of vitamin e acetate within the pulmonary system, increasing amount of reports suggest that such assumptions are erroneous. importantly, 10 there is a lacking histological evidence of exogenous lipoid pneumonia (elp) in patients suffering from evali, despite the prevalence of intraalveolar lipid-laden macrophages in bal fluids. for instance, when a 63-year-old woman had regularly smoked cod-liver oil, she acquired a non-oncologic perihilar mass in the right middle lobe of her lung, indicative of elp [43] , but these elp-like histological signs were mostly absent in patients with evali [11] . as guerrini 15 and colleagues importantly mention, intraalveolar lipid-laden macrophages do not always originate from an excessive uptake of exogenous lipids, but may often emerge as a common immunopathological response following sustained inflammation [44] . however, unmodified vitamin e is indicated in the downregulation of cd36 [45] , which functions to promote the formation of lipid-laden macrophages (foam cells) [46] . furthermore, vitamin e also ameliorates this hypothesis also does not provide us with an exact mechanism by which vitamin e acetate may initiate inflammation. since vitamin e acetate is a viscous liquid at physiological temperature, activation of the nlrp3 inflammasome through crystal-induced lysosomal rupture as in models of silicosis [48] seems unlikely, despite robust activation of the inflammasome in e5 cigarette users [49] . vitamin e is also indicated in an active inhibition of 5-lipoxygenase (5-lo), which converts fatty acids to leukotrienes, promoting inflammation [50, 51] . importantly, vitamin e acetate is also reported to inhibit 5-lo activity [50], despite being twice less potent than the unmodified vitamin, supporting the view that vitamin e acetate does not induce elp in patients with evali via the inflammatory response. 10 in the field of diabetes mellitus, vitamin e is a potent agonist of dgkα, which catalyzes the conversion of diacylglycerol (dag) to phosphatidic acid (pa) and thereby inhibits the catalytic activity of pkcα [52] [53] [54] . agonism of dgkα by vitamin e derivatives are known to be 15 dependent on the chromane double ring of the molecule, as both vitamin e analogs containing the moiety, such as troglitazone and trolox, and non-antioxidative vitamin e derivatives, such as vitamin e succinate, exhibited robust activation and subsequent plasmalemmal translocation of the kinase [55] . vitamin e acetate may also antagonize the catalytic activity of pkcα in a dgkindependent manner, as there are studies indicating that the substance is capable of competing 20 with dag for its binding site in pkcα [56]. intriguingly, d-α-tocopherol, but not d-β-tocopherol nor d-γ-tocopherol exhibited robust inactivation of pkcα, indicating a pivotal role of methylation at c5 and c7 of the chromanol structure [57] . supplementation of vitamin e acetate in murine models of diabetic cardiomyopathy showed largely protective role for the chemical [58] , but it is worth to note that most of the substances supplemented via dietary uptake undergo hydrolysis to yield vitamin e. the protective effect of vitamin e derivatives in diabetes mellitus was completely ameliorated in dgkα knockout mice, indicating a pivotal role of the kinase in this antidiabetic signaling cascade [54] . 5 since the observed level of vitamin e acetate in bal fluids is of same orders of magnitude with that of dag, a potent second messenger with which vitamin e acetate competes for binding [59] , the activity of the substance as a modulator of dgk-pkc pathway is physiologically relevant. however, the reported anti-inflammatory effects of d-α-tocopherol in the pulmonary system through post-translational inactivation of pkcα significantly undermines this hypothesis 10 [60, 61] . since many observations suggest that the antagonism of pkcα by d-α-tocopherol is independent of its antioxidative property [57], it is anticipated that vitamin e acetate might play an analogous anti-inflammatory role in the pulmonary system [62, 63] . however, whether the esterified derivative antagonizes pkcα still remains to be investigated. overall, the modulation of dgk-pkc pathway by vitamin e acetate seems yet incapable of accounting for the 15 observation of pro-inflammatory intraalveolar lipid-laden macrophages in patients with evali, although there is yet lacking amount of evidence to completely rule out this hypothesis. when vitamin e is administered into the biological system, it transforms into a plethora of 20 bioactive metabolites [64]. this includes several of the pxr agonists, such as α-tocopherol-13'-cooh, γ-tocotrienol, and garcinoic acid [65, 66] . since pxr forms a heterodimer with 9cis retinoic acid receptor (nr2b) to activate the transcription of cytochrome p450 monooxygenase genes indicated in the clearance and detoxification of xenobiotic substances 13 [67] , pro-agonist role of vitamin e acetate may be relevant in the pathophysiology of evali. indeed, polymorphisms in the cytochrome p450 genes have been associated with drug-induced interstitial lung diseases (diild), characterized by coarse reticular opacity and intraalveolar lipid-laden macrophages [68] . this pathology is consistent with that of evali, wherein patients 5 often reported patterns of giant-cell interstitial pneumonia [4] . in this picture, evali can be seen as a variant of diild caused by an excessive accumulation of vitamin e acetate in the pulmonary system. despite its pathophysiology being not fully characterized, diild often involves the generation of reactive oxygen species [69, 70] . vitamin e acetate, however, is known to protect the biological system against reactive oxygen species even in the absence of 10 apparent hydrolysis [24] , possibly through its inhibition of 5-lo [15] or through infinitesimal hydrolysis to vitamin e as previously speculated [24] . furthermore, diild is a highly heterogenous disorder, that is often dependent on genetic polymorphisms rare enough to avert federal regulations during drug approval [71, 72] . for instance, the demonstration of respiratory symptom after oral administration of fenfluramine or dexfenfluramine was on a patient with a 15 rare cyp2d6*1/*3 haplodeficient variant of the cytochrome p450 2d6 (cyp2d6) gene [68] . how haplodeficiency of the cyp2d6 gene contributes to the pathogenesis of diild remains unclear. if vitamin e acetate behaves as a pro-agonist of pxr, a transcriptional activator of cytochrome p450 genes, and thereby contributes to the pathogenesis of evali, the symptoms of evali 20 should be replicated by inhalation of other well-established pxr agonists, such as corticosteroids [73] [74] [75] . nebulized budesonide or fluticasone, however, did not induce respiratory distress when inhaled repeatedly (inhalation of 125-200 μg corticosteroids each session, 2-4 times daily, 8 days) in young children with a severe onset of asthma [76] . furthermore, even in the absence of 14 vitamin e acetate, vaping induced significant increase in the activity of cytochrome p450 enzymes, including those hydroxylates vitamin e, such as cyp2b1, cyp2c11, and cyp3a1, but without apparent respiratory distress [77] . however, it remains to be studied whether an excessive accumulation of vitamin e acetate produces pxr-agonizing metabolites above a 5 certain threshold such that it may induce an acute respiratory distress. overall, the pro-agonist role of vitamin e acetate on pxr seems relevant in the pathophysiology of evali, but there is yet lacking amount of evidence which indicates that the pxr agonism drives the pathogenesis of evali. 10 recent developments in membrane biophysics indicate that an unmodified vitamin e has an active role in lateral phase separation. due to the rigid chromane double ring, which significantly reduces the entropic cost required for its association with cholesterol [78] , unmodified vitamin e efficiently releases the line tension (i.e. two-dimensional counterpart of a surface tension) 15 between the liquid-disordered l α and the liquid-ordered l o phase of lipid polymorphs [79] . indeed, oral supplementation of vitamin e acetate in hiv/aids patients, which is readily converted to vitamin e by cellular esterases, has been successful in reducing the viral load [80] , as the molecule disrupts the tensile two-dimensional l α /l o phase boundary required for viral entry [81, 82] . in membrane biophysics, this vitamin is classified as a linactant [83] , which is a 20 two-dimensional counterpart of a surfactant, as it reduces the line tension at the two-dimensional phase boundaries (fig. 2a) . in explanation, when one puts a drop of oil into the water, gravity and surface tension compete to generate the lobular shape of the droplet. the addition of sodium dodecyl sulfate (sds), a well-known surfactant, reduces the surface tension such that the oil droplet loses its ability to maintain its structure against gravitational force. as a consequence, oil emulsifies into the water, if not become completely miscible [84] . similarly, when one adds vitamin e onto the lipid bilayer exhibiting l α /l o phase separation, it reduces the line tension, which competes with entropy to 5 form an enlarged cholesterol-enriched microdomain. as it has been shown that the molar ratio of vitamin e within a typical lipid bilayer is insufficient to completely abolish lateral phase separation [85] , vitamin e acts to reduce the size of the microdomain and thereby emulsifies cholesterol-enriched l o into cholesterol-depleted l α (fig. 2c) . despite the fact that the line-active property of vitamin e acetate has not yet been explicitly tested, the small size and the abundance 10 of ideally localized nonbonding electron donors of the ester moiety provide ample reason to hypothesize that the substance is a linactant. the content of vitamin e within the lipid mixture that is sufficient to function as a potent linactant is typically below 10 mol% [79, 85] , which is comparable to that of vitamin e acetate, estimated based on its concentration in bal fluid samples from patients with evali. 15 an important consequence of the dissemination of the cholesterol-enriched microdomain is a profound increment in the surface viscosity of pulmonary surfactants [86] . lateral phase separation is an important source of free area, defined as the difference between observed and minimum area per molecule [87] . this is analogous to the observation of reduction in the total volume after mixing ethanol with water. in such a case, the phenomenon can be interpreted as if 20 the free volume of each molecule has decreased following mixing. similarly, mixing of l o with l α results in a substantial decrease in the free area, while demixing induces its subsequent increase. according to the free area theory of surface viscosity [88] , surface viscosity exponentially increases following the reduction of free area, driven by reduced tensile force along the two-dimensional phase boundaries. indeed, a mere 3% decrease in the free area resulted in a striking 12-fold increase in the surface viscosity of pulmonary surfactants [87] . in accordance, upon hyperpnea, the biological system increases free cholesterol level in pulmonary surfactants, to reduce surface viscosity, which is required for facilitated respiration [89] . 5 similarly, the reduced free area following the inhalation of vitamin e acetate may considerably increase the surface viscosity of the pulmonary surfactant, resulting in a disrupted respiratory compression-expansion cycling and a subsequent hypoxemia (fig. 2b) . in this picture, intraalveolar lipid-laden macrophages are consequences of hypoxemia-induced excessive intracellular accumulation of triglycerides [90] , and extensive vacuolization, 10 multinucleation, and reactive hyperplasia observed in type ii alveolar pneumocytes are products of an extensive tissue hypoxia [91, 92] . taking into account that the pulmonary-associated surfactant protein b (sp-b) often cooperates with cholesterol in reducing the surface viscosity of pulmonary surfactants during respiratory compression-expansion cycling [86], other than its known role in the reduction of surface tension in the steady state, it is worth to note that the 15 partial deficiency of the protein results in a respiratory distress analogous to those observed in patients with evali [93] . in sum, vaporized vitamin e acetate, a thermostable derivative of the well-established linactant, may substantially increase the surface viscosity of pulmonary surfactants and thereby confer the pathogenesis of evali. 20 evaluating the hypothesis the above-described biological actions of vitamin e derivatives are closely intertwined to each other [83, 94] , and the effect of vitamin e acetate on the pulmonary system in patients with evali is likely to be the sum of all these actions, rather than originating from a single action of the vitamin derivative. for instance, cholesterol-enriched microdomains, or lipid rafts [95] , are involved in a plethora of cellular activities, including pkcα [96] and 5-lo signaling [97] . as a consequence, it is worth to note that the evaluation of these hypotheses should focus on identifying the major driving force for the pathogenesis of evali, rather than a sole cause, 5 which most likely does not exist. to evaluate whether the line-active property of vitamin e acetate is driving the pathogenesis of evali, we must answer the following questions. first, is vitamin e acetate, like d-α-tocopherol, a potent linactant? if it is, to what extent does the substance reduce the line tension at the twodimensional phase boundaries and increase the surface viscosity? molecular dynamics 10 simulations, such as those previously introduced by rosetti and colleagues [98] , would particularly be useful, as they enable us to roughly estimate the fold change in the surface viscosity of pulmonary surfactants and thereby to evaluate the validity of the hypothesis. second, are linactants, in general, capable of inducing respiratory distress when inhaled through ecigarettes? one obvious experiment that must be done is the repeated inhalation of hybrid lipids 15 in murine models. hybrid lipids, which are phospholipids that contain both saturated and unsaturated acyl chains, are one of the most widely accepted class of linactants [98] [99] [100] [101] . as a consequence, repeated inhalation of hybrid lipids, analogous to those attempted by bhat and colleagues, should induce similar histological signs, for the hypothesis to hold. to rule out the potential role of vitamin e acetate as an inducer of gel-liquid crystalline phase transition, rescue 20 experiments using an inhalation setup for dimethyl sulfoxide (dmso), which abrogates gelliquid crystalline phase transition [102] , can be attempted. to rule out the possibility that vitamin e acetate drives the pathogenesis of evali through modulating dgk-pkc or pxr signaling, vitamin e acetate inhalation experiment using either pkcα [103] or pxr knockout mice [104] can be pursued. characterization of the lipid composition of the intraalveolar lipidladen macrophages is also crucial, as it may assist us to rule out the hypothesis that an acute respiratory distress associated with evali is indeed a form of elp. lastly, as we still suffer from the lack of characterization of the type of injury in evali, i propose an rna sequencing 5 (rna-seq) experiment for lung tissues obtained from murine models of evali [42] . analyses on the level of transcripts associated with the biological action of the vitamin, such as cytochrome p450 monooxygenase genes, hypoxia-inducible factor 1 (hif-1), and nrf2, as well as gene ontology analyses would greatly assist us to better define the pathology of the new respiratory disorder. rna-seq experiment would also allow us to develop reliable biomarkers for 10 evali to better assist health care providers in the differential diagnosis of the vaping-induced respiratory disorder against viral infections. living in the era of the pandemic outbreak of the coronavirus disease 2019 (covid-19), wherein tens of millions of people worldwide are being hospitalized with symptoms often indistinguishable from those of evali [105, 106] , establishing diagnostic biomarkers for evali would particularly be valuable. in summary, i discussed several possible mechanisms by which vitamin e acetate may drive the pathogenesis of evali and specifically advocated the role of vitamin e acetate as a linactant (table 1) . based on recent discoveries from the field of membrane biophysics, i proposed that 5 the alleged linactivity of vitamin e acetate, a thermostable derivative of a well-established linactant, significantly increases the surface viscosity of pulmonary surfactants in the alveoli to confer acute respiratory distress associated with evali. this hypothesis leads to new possible medication approaches for the new pulmonary disease. if it is true that the line-active property of the vitamin derivative is what is causing the disease, supplementation of pulmonary surfactants 10 as well as corticosteroid treatments should be valid. to reduce the elevated viscosity of pulmonary surfactants, pulmonary surfactants which retain a moderate level of cholesterol, such as infasurf [107] , may be recommended for use. in addition, in a biophysical perspective, since the entropy component of the free energy, which is proportional to the temperature of the system, works against lateral phase separation in regular solutions [108, 109] , one can reverse the effects 15 of vitamin e acetate by slightly lowering the temperature of the system. controlled hypothermia to rescue lateral phase separation and thereby reduce surface viscosity, as introduced by autilio and colleagues [110] , might be a useful way to manage acute respiratory distress syndrome associated with evali. the current outbreak of evali is an emerging crisis affecting a great portion of the global 20 population. as pathophysiologists, we have a duty to decipher the pathophysiology of evali for the good of all patients suffering from the disease, especially after the recent identification of the widely utilized derivative of the vitamin as one of the causal agents for the new catastrophic pulmonary disease. that vitamin e acetate may facilitate gel-liquid crystalline phase transition to confer acute 5 respiratory distress [12] . in this picture, vitamin e acetate perturbs the packing of phospholipids within the lipid bilayer such that the system thermodynamically prefers the liquid crystalline phase over the gel phase. however, cholesterol, which exists in large excess to vitamin e acetate in the biological membrane, not only exerts similar effect in model saturated phospholipid bilayers, but also reportedly abolishes gel-liquid crystalline phase transition [38] . therefore, gel-10 liquid crystalline phase transition may be irrelevant in the pathogenesis of evali. reduced line tension within the two-dimensional phase boundary confers smaller microdomains 5 and decreases the free area of lipids [87] . as a result, the surface viscosity of pulmonary surfactants exponentially increases to perturb the dynamics of respiratory compressionexpansion cycling, causing acute respiratory distress analogous to those seen in patients with evali. update: characteristics of a nationwide outbreak of e-cigarette, or 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cd36-dependent signaling cascade is necessary for macrophage foam cell formation vitamin e ameliorates ox-ldl-induced foam cells formation through modulating the activities of oxidative stress-induced nf-κb pathway silica crystals and aluminum salts activate the nalp3 inflammasome through phagosomal destabilization electronic versus combustible cigarette effects on inflammasome component release into human lung inhibition of 5-lipoxygenase by vitamin e endogenous metabolites of vitamin e limit inflammation by targeting 5-lipoxygenase diacylglycerol-protein kinase c activation by vitamin e in aorta of diabetic rats and cultured rat smooth muscle cells exposed to elevated glucose levels α-tocopherol specifically inactivates cellular protein kinase c α by changing its phosphorylation state diacylglycerol kinase alpha is involved in the vitamin e-induced amelioration of diabetic nephropathy in mice importance of chroman ring and tyrosine endothelial relaxation is disturbed by oxidative stress in the diabetic rat heart: influence of tocopherol as antioxidant intracellular diacylglycerol: a mitogenic second messenger proposable as marker of transformation in 15 squamous cell carcinoma of the lung α-tocopherol inhibits the respiratory burst in human monocytes: attenuation of p47(phox) membrane translocation and phosphorylation opposing immunoregulatory functions during inflammation by regulating leukocyte recruitment the α-tocopherol form of vitamin e reverses age-associated susceptibility to streptococcus pneumoniae lung infection by modulating pulmonary neutrophil recruitment the alpha-tocopherol form of vitamin e boosts elastase activity of human pmns and their ability to kill streptococcus pneumoniae vitamin e biotransformation in humans the long chain α-tocopherol metabolite α-13'-cooh and γ-tocotrienol induce p-glycoprotein expression and activity by activation of the pregnane x receptor in the intestinal cell line ls 180 garcinoic acid is a natural and selective agonist of pregnane x receptor the nuclear pregnane x receptor: a key regulator of xenobiotic metabolism relationship between drug-induced interstitial lung diseases and cytochrome p450 polymorphisms drug induced interstitial lung disease drug-induced interstitial lung disease: mechanisms and best diagnostic 20 approaches role of cytochrome p450 polymorphisms in the development of pulmonary drug toxicity: a case-control study in the netherlands whole genome sequencing to identify predictive markers for the risk of drug-induced interstitial lung disease pregnane x receptor and retinoid x receptor-α expression in human hepatocytes: synergistic increase of cyp3a4 induction by pregnane x receptor activators pxr-mediated induction of human cyp3a4 and mouse cyp3a11 by the glucocorticoid 10 budesonide identification and validation of novel human pregnane x receptor activators among prescribed drugs via ligand-based virtual screening effectiveness of high repeated doses of 15 inhaled budesonide or fluticasone in controlling acute asthma exacerbations in young children e-cigarettes induce toxicological effects that can raise the cancer risk cholesterol as a co-solvent and a ligand for 20 membrane proteins tuning membrane phase separation using nonlipid amphiphiles effects of vitamin e and c supplementation on oxidative stress and viral load in hiv-infected subjects line tension at lipid phase boundaries as driving force for hiv fusion peptide-mediated fusion hiv virions sense plasma membrane heterogeneity for cell entry line active molecules promote inhomogeneous structures in membranes: theory, simulations and experiments capillarity and wetting phenomena the antioxidant vitamin e as a membrane raft modulator: tocopherols do not abolish lipid domains effect of cholesterol and surfactant protein b on the viscosity of phospholipid mixtures effect of cholesterol nanodomains on monolayer morphology and dynamics in-plane steady shear viscosity of monolayers at the air/water interface and its dependence on free area effect of hyperpnea on the cholesterol to disaturated phospholipid ratio in alveolar surfactant of rats hypoxia converts human macrophages into triglyceride-loaded foam cells lysosomal alterations in hypoxic and reoxygenated hearts. i ultrastructural and cytochemical changes hif and the lung: role of hypoxia-inducible factors in pulmonary development and disease partial deficiency of surfactant protein b in an infant with chronic lung disease vitamin e: regulatory role on signal transduction functional rafts in cell membranes the nk1 receptor localizes to the plasma membrane microdomains, and its activation is dependent on lipid raft integrity protein profiling of plasma membranes defines aberrant signaling pathways in mantle cell lymphoma molecular insight into the line tension of bilayer 20 membranes containing hybrid polyunsaturated lipids partitioning of lipids at domain boundaries in model membranes modulation of a small two-domain lipid vesicle by linactants physical properties of the hybrid lipid popc on micrometer-sized domains in mixed lipid membranes insights into the dynamics of dmso in phosphatidylcholine bilayers enac activity and expression is decreased in the lungs of protein kinase c-α knockout mice pregnane x receptor knockout mice display aging-dependent wearing of articular cartilage clinical features of patients infected with 2019 novel coronavirus in wuhan, china notes from the field : e-cigarette, or vaping, product use-associated lung injury cases during the covid-19 response -california commercial versus native surfactants: surface activity, molecular components, and the effect of 20 calcium themodynamics of high polymer solutions solutions of long chain compounds controlled hypothermia may improve kim at the republic of korea army for their administrative assistance. key: cord-342335-awu50iev authors: carr, anitra c.; rowe, sam title: factors affecting vitamin c status and prevalence of deficiency: a global health perspective date: 2020-07-01 journal: nutrients doi: 10.3390/nu12071963 sha: doc_id: 342335 cord_uid: awu50iev a recent review of global vitamin c status has indicated a high prevalence of deficiency, particularly in lowand middle-income countries, as well as in specific subgroups within high-income countries. here, we provide a narrative review of potential factors influencing vitamin c status globally. the in vivo status of vitamin c is primarily affected by dietary intake and supplement use, with those who supplement having a higher mean status and a lower prevalence of deficiency. dietary intake can be influenced by cultural aspects such as traditional cooking practices and staple foods, with many staple foods, such as grains, contributing negligible vitamin c to the diet. environmental factors can also affect vitamin c intake and status; these include geographic region, season, and climate, as well as pollution, the latter partly due to enhanced oxidative stress. demographic factors such as sex, age, and race are known to affect vitamin c status, as do socioeconomic factors such as deprivation, education and social class, and institutionalization. various health aspects can affect vitamin c status; these include body weight, pregnancy and lactation, genetic variants, smoking, and disease states, including severe infections as well as various noncommunicable diseases such as cardiovascular disease and cancer. some of these factors have changed over time; therefore, we also explore if vitamin c status has shown temporal changes. overall, there are numerous factors that can affect vitamin c status to different extents in various regions of the world. many of these factors are not taken into consideration during the setting of global dietary intake recommendations for vitamin c. due to random genetic mutations that have occurred during our evolution, humans have lost the ability to synthesize ascorbate in our livers [1] . therefore, instead of being a normal liver metabolite, as is the case for most other animal species, ascorbate has instead become a vitamin and must be obtained through the diet to prevent hypovitaminosis c and outright deficiency [2] . in a recent review, we described the global status of vitamin c and the prevalence of deficiency as assessed by plasma concentrations [3] . whilst vitamin c concentrations are normally tightly controlled in humans with adequate intake, a number of studies suggest that hypovitaminosis c and deficiency are not uncommon worldwide and may be very common in some settings. vitamin c is well absorbed in small quantities. uptake occurs primarily through the sodium-dependent vitamin c transporter-1 (svct-1), which is rapidly saturated, allowing relatively limited absorption of vitamin c per serving [4] . vitamin c is then accumulated at varying concentrations in different body tissues [5] . the vitamin is excreted unchanged in the urine, but reuptake occurs in the renal tubules [6] . further loss of vitamin c occurs through the oxidation of ascorbic acid to dehydroascorbic acid which may then be recycled to ascorbic acid or undergo further oxidative decomposition [7] . thus, in vivo, vitamin c concentrations are affected by a range of factors that include dietary intake, absorption, distribution, oxidative decomposition, and elimination. vitamin c acts as an important antioxidant and plays a myriad of functions in optimal health and prevention of disease [8, 9] . even mild insufficiency or hypovitaminosis c can be associated with symptoms such as low mood [10] . more severe deficiency can be associated with a range of clinical presentations [11] . prolonged severe deficiency results in the clinical syndrome of scurvy, a condition that continues to be diagnosed in individuals and occasionally in public health outbreaks to this day [12] ; if left untreated, scurvy is a fatal disease. the optimum intake and concentrations of vitamin c, however, have been subject to debate and recommended values are not universal [13] . due to a range of benefits, a number of international authorities have increased their dietary recommendations for vitamin c from those previously recommended on the basis of preventing scurvy [13] . although these recommendations generally take into account variations in requirements based on age, sex, pregnancy and lactation, and sometimes smoking status, there are many other factors that affect vitamin c status that are not taken into consideration by these global authorities. in this review, we highlight the numerous factors that impact on vitamin c status and prevalence of deficiency globally. dietary intake of vitamin c is a key determinant of body status, with the amount consumed and the frequency of consumption correlating with plasma status and prevalence of deficiency (table 1) [14, 15] . fresh fruit and vegetables are the major dietary source of vitamin c, with fruit intake correlating more strongly with plasma vitamin c status [16, 17] . foods rich in vitamin c include oranges and other citrus fruit, guavas, kiwifruit, cranberries, strawberries, papayas, mangoes, melons, cantaloupe, spinach, swiss chard, tomatoes, asparagus, and brussels sprouts ( figure 1 ) [18] . in contrast, grains (e.g., rice, millet, wheat/couscous, corn), some starchy roots and tubers, meat (other than liver), eggs, and dairy contain very little vitamin c. dietary intake dietary intake, particularly fruit intake, correlates with improved vitamin c status and decreased prevalence of deficiency; is dependent on the amount consumed, frequency of consumption, and type of food consumed as the vitamin c content of food varies. high dietary fat and sugar intake are associated with decreased vitamin c intake and status. [14] [15] [16] [17] [19] [20] [21] [22] [23] [24] staple foods staple foods such as grains (e.g., rice, millet, wheat/couscous, corn) and some starchy roots and tubers are low in vitamin c; populations who consume these staples can have lower overall vitamin c intake. [18, 25] traditional cooking practices suboptimal diet is an important preventable risk factor for noncommunicable diseases, and a low intake of fruit was found to be the third leading dietary risk for deaths (two million deaths) and disability-adjusted life-years (65 million dalys) globally [31] . the world health organization recommends at least 400 g (i.e., five portions) of fruit and vegetables per day, excluding potatoes, sweet potatoes, cassava, and other starchy roots [32] . historically, scurvy has been reported in refugee camps in ethiopia; the relief food distributed to the refugees was almost completely deficient in vitamin c, and the environment where the camps were located precluded an adequate supply of fresh food [33] . however, vitamin c deficiency may even be common in fertile areas of africa, such as uganda [34] . there have been a number of outbreaks of clinical scurvy in recent years, including figure 1 . estimated vitamin c content of selected fruit and vegetables. data derived from the united states department of agriculture (https://fdc.nal.usda.gov/). note that vitamin c content can vary depending on the plant variety, and cooking may decrease the vitamin c content to variable extents. pulses include kidney beans, chickpeas, mung beans, pinto beans, soybeans, lentils, peanuts, split peas; nuts include hazelnuts, pistachios, macadamia nuts, pecans, walnuts, brazil nuts, cashew nuts; seeds include chia, flax seeds, pumpkin seeds, sunflower seeds, sesame seeds; grains include rice, millet, wheat/couscous, cornmeal. animal products, such as meat (other than liver), eggs, and milk contain negligible vitamin c. dotted lines: lower line indicates daily intake to prevent scurvy (10 mg/d); upper line indicates daily intake for optimal health (200 mg/d). suboptimal diet is an important preventable risk factor for noncommunicable diseases, and a low intake of fruit was found to be the third leading dietary risk for deaths (two million deaths) and disability-adjusted life-years (65 million dalys) globally [31] . the world health organization recommends at least 400 g (i.e., five portions) of fruit and vegetables per day, excluding potatoes, sweet potatoes, cassava, and other starchy roots [32] . historically, scurvy has been reported in refugee camps in ethiopia; the relief food distributed to the refugees was almost completely deficient in vitamin c, and the environment where the camps were located precluded an adequate supply of fresh food [33] . however, vitamin c deficiency may even be common in fertile areas of africa, such as uganda [34] . there have been a number of outbreaks of clinical scurvy in recent years, including in tribesmen in kenya and during the afghanistan winter [35, 36] , and cases of clinical scurvy continue to be diagnosed related to poor intake even in high-income countries [12, 37] . food consumption is influenced by a number of factors, such as geographical, economic, social, and cultural [25] . it is well known that economic factors, such as poverty, can limit the consumption of healthy foods. furthermore, tradition and social customs may influence the consumption of a variety of foods. for example, a study in nepal highlighted cultural beliefs around menstruation, pregnancy, and lactation that decreased micronutrient intake and intrahousehold disfavouritism towards women in the distribution of micronutrient-rich foods [27] . in low-and middle-income countries (lmics), geographic considerations and agricultural practices influence the production and consumption of staple foods, which can greatly influence vitamin c intake. for example, countries whose populations consume grains such as rice and millet as staple foods (e.g., in asia and parts of africa) tend to have lower intakes of vitamin c [18, 25] . in contrast, some areas of africa and latin america where yams and sweet potato are staple foods, vitamin c intakes may be higher. however, the vitamin c content of food can also vary depending on the time of harvest, transportation and storage conditions, and food preparation conditions. for example, the vitamin c content of some staple foods, e.g., cassava, is significantly depleted by different processing methods, which could lead to inaccuracies in estimated vitamin c intake [38] . vitamin c is heat-labile and can be destroyed by cooking; the lower vitamin c status of indians and malays living in singapore is thought to be partly due to its destruction by more prolonged cooking [26] . an optimal vitamin c intake (i.e., 200 mg/d) can be obtained from five-plus daily servings of fresh fruit and vegetables, providing that at least one or two servings are high vitamin c foods, however, this is not always possible for many people around the world. therefore, taking supplements in addition to dietary intake can help to maintain optimal vitamin c status. there are many different forms of vitamin c supplements; however, research indicates that these generally have the same bioavailability as food-derived vitamin c [39] . numerous studies have found that even in developed countries, where there is no shortage of fresh fruit and vegetables, those who consume supplements have significantly higher vitamin c status and/or lower prevalence of deficiency (table 2) . two large health surveys carried out in canada (chms) and the usa (nhanes iv) reported 20% supplement use in canada and 37 to 47% supplement use, for men and women, respectively, in the usa [14, 15] . it should be noted, however, that in these surveys, supplement use was considered to be as little as once in the previous month. nevertheless, both studies found vitamin c status was at least 20 µmol/l higher in supplement users, with a low prevalence of deficiency (0-2%) in those who supplemented [14, 15] . two studies in the uk indicated that people who did not supplement had a two-fold odds ratio of having a vitamin c status of <28 µmol/l and a three-fold odds ratio of their vitamin c status being <11 µmol/l, relative to concentrations >28 µmol/l [19, 28] . table 2 . effect of socioeconomic factors on vitamin c status. socioeconomic status/deprivation individuals with lower socioeconomic status or higher deprivation have lower vitamin c status and a higher prevalence of deficiency; this is partly due to the higher cost of good quality, nutrient-dense food. [15, 19, 21, 24, 28, [40] [41] [42] [43] [44] [45] education and social class similarly, individuals with lower education and manual occupations have lower vitamin c status. [14, 17, 20, 28, 42] institutionalized institutionalized elderly, and other institutionalized individuals (e.g., priests, prisoners, boarding school children) have lower vitamin c status and a higher prevalence of deficiency; this is partly due to a lower dietary intake. [41, [46] [47] [48] geographic differences in vitamin c status have been reported (table 3) ; there are likely many factors that contribute to the observed differences. for example, significant differences in vitamin c status and prevalence of deficiency were observed between finland and neighboring russia (where strikingly low plasma concentrations were observed) [17] . geographical differences in the consumption of fresh fruit and vegetables were apparent, which were associated with deficiency. low educational status was also noted to be associated with deficiency on the russian side of the border [17] . another study carried out in five countries across europe indicated a difference in the vitamin c status of women, with the biggest differences being observed between northern ireland and the republic of ireland [49] . no differences in vitamin c status were observed for men from these different countries, whilst women had higher vitamin c status than the men in three of the five countries. mosdol et al. [19] reported that low-income participants living in scotland and northern island had a lower prevalence of deficiency than those living in england, whilst those living in wales had a higher prevalence of deficiency. as part of the su.vi.max trial, france was divided into seven regions, and vitamin c status was found to be significantly lower in the northern region [50] . the reasons for these regional differences are unknown. in a large study of elderly people in india, a higher prevalence of deficiency was observed in the north (74% deficiency) compared with the south (46% deficiency) [24] . similarly, in mexico, a higher prevalence of deficiency was observed in children in the north and south regions (~26% deficiency) compared with those living in mexico city (12% deficiency) [40] . this could reflect differences in the socioeconomic status between urban and rural environments. table 3 . environmental factors affecting vitamin c status. geographical region vitamin c status varies by geographical region, both within and between countries; this could partly reflect differences in socioeconomic status and available foods. [17, 19, 24, 40, 41, [49] [50] [51] season vitamin c status varies seasonally between countries, likely reflecting different crops and thus the types and/or amounts of vitamin c-rich foods consumed. [24, 30, 52, 53] climate drought and harsh winter climates have been associated with outbreaks of clinical scurvy. [36] pollution exposure to environmental pollutants, e.g., smoke, can deplete vitamin c status; this is partly due to enhanced oxidative stress. [24, 42, [54] [55] [56] [57] [58] since fresh fruit and vegetables are the major source of vitamin c for most people, it is perhaps not surprising that there have been reports of seasonal differences in vitamin c status (table 3) . surprisingly, however, studies carried out in england and china have indicated that vitamin c status tends to be highest in winter and lowest in autumn, with up to 10 µmol/l difference between these seasons [30, 52] . another study in china indicated a much higher vitamin c status in winter relative to spring [53] . this likely reflects the types or amounts of vitamin c-rich foods being consumed in winter. similar trends were observed in northern india, with less deficiency being observed in the winter months; however, in southern india, the winter months were associated with a higher prevalence of deficiency [24] . this likely reflects the different climatic and agricultural patterns across the subcontinent. it is possible that seasonal variances in plasma vitamin c concentrations are affected by baseline vitamin c status, i.e., whether the individual is already saturated or not. bates et al. [59] reported seasonal variations in participants with higher intakes and blood status at baseline compared with little variation in those with low intakes and status, the latter likely due to a depleted body pool and preferential uptake of the vitamin by tissues. changes in climate, such as drought, are also likely to impact on the vitamin c status of the populations reliant on local foods in the affected region [36] . this also leads to increased reliance on staple crops like cassava that lose their vitamin content prior to consumption [38] . currently, over half of the world's population lives in urban areas, and who data indicate that more than 80% of people living in urban areas are exposed to air quality levels that exceed who guideline limits, with lmics suffering from the highest exposures [60, 61] . air pollution causes an estimated seven million premature deaths worldwide every year, primarily resulting from increased mortality from strokes, heart disease, chronic obstructive pulmonary disease, lung cancer, and acute respiratory infections [61] . environmental air pollution, such as smoke derived from burning biomass, can comprise reactive species that potentially affect in vivo antioxidant status [24] . another example is environmental tobacco smoke, which is an underestimated pollutant in many parts of the world. exposure to environmental tobacco smoke is associated with depleted vitamin c status in both nonsmoking adults and children [42, [54] [55] [56] [57] [58] . tribble et al. [54] found that the vitamin c status of passive smokers was significantly lower than that of nonexposed nonsmokers, despite comparable dietary intakes of the vitamin. hypovitaminosis c was observed in 12% of passive smokers, but not in nonexposed nonsmokers. analysis of the data of children from the nhanes iii and iv surveys revealed a dose-response relationship between levels of tobacco exposure and serum vitamin c concentrations [55, 56] . not all studies in adults, however, have shown effects of passive smoking on vitamin c status [62] [63] [64] [65] . nevertheless, supplementation with vitamin c and other antioxidants was found to decrease oxidative biomarkers in participants exposed to environmental tobacco smoke [62, 66] . in high-income settings, females appear to have higher vitamin c status and a lower prevalence of deficiency than males [3] . according to mccall et al. [28] , uk males have a four-fold odds ratio of deficiency compared with females ( table 4 ). the difference in vitamin c status between males and females is thought to be partly a result of a volumetric dilution effect due to the higher fat-free mass of males [29] . there are also differences in dietary intakes between men and women, with women generally having comparable or higher intakes than men in high-income countries, although this difference is less apparent in some low-income settings [3] . it should also be noted that pregnancy and lactation typically lower women's vitamin c status due to hemodilution and the needs of the developing fetus and growing infant (see below). many countries have higher dietary recommendations for men (to take into account the differences in body mass) and for pregnant and lactating women [13] . table 4 . effect of demographic factors on vitamin c status. males generally have lower vitamin c status, and a higher prevalence of deficiency, than females; this is partly a result of a volumetric dilution effect due to the higher fat-free mass of males. this difference is less apparent in some low-and middle-income countries. [14, 15, 17, 19, 22, 24, 26, [28] [29] [30] 42, 43, 49, 50, 53, [67] [68] [69] [70] age both children and elderly tend to have higher vitamin c status in high-income settings; this could partly be due to lower body weight. elderly can have a higher prevalence of vitamin c deficiency in some settings; this could be due to lower intake and/or comorbidities. [14, 15, 20, 24, 28, 29, 41, 50, 71, 72] race in the us and uk, african-caribbean and south asian people had a lower status than caucasians. in south asia, malays and indians had a lower status than chinese; this is thought to be partly due to differences in culinary practices. differences are more apparent between women of different races. [15, 26, 30, 73, 74] some studies carried out in people aged >60 years (e.g., the french pola study and the british national diet and nutrition survey) have shown lower vitamin c status than other studies carried out in the same countries with younger age groups (e.g., the french su.vi.max study and the european epic-norfolk study); however, it is not ideal to compare values between different studies due to potential methodological differences. a number of studies have indicated that older age within the same study population is associated with an increased prevalence of vitamin c deficiency, particularly in men, and older men also tend to have a lower vitamin c intake than older women [20, 24, 28, 71] . however, a counterpoint to this is that overall vitamin c status can be higher in older people [15, 29, 50] , although not in all cases, as was found in men in finland who had lower vitamin c status with older age [72] . schleicher et al. found a u-shaped curve for vitamin c status over the age range of 6 to 60+ years [15] . it is possible that the lower body mass of children and elderly, due to age-related frailty, could contribute to their higher vitamin c status. however, there are, clearly, subpopulations within the aging population who have increased deficiency, likely due to lower intake and/or comorbidities. a number of studies have indicated that vitamin c status varies by race (table 4 ; reviewed in [74] ). the prevalence of vitamin c deficiency appeared to be highest amongst south asians and was thought to be partly due to traditional cooking practices. it was also suggested that the high proportion of individuals with low vitamin c concentrations in south asian populations might contribute to their higher rates of cardiovascular disease. only a few studies have assessed different ethnic groups within the same study [15, 26, 30, 73] . in 1980, koh et al. [73] assessed vitamin c status in a cohort of black and white participants in mississippi, usa. black males and females had significantly lower vitamin c status than white males and females (up to 10 µmol/l difference for females). the more recent us nhanes iv survey also found significantly lower vitamin c status in black females compared with white females [15] . in london, the vitamin c status of black and south asians was significantly lower than white participants (up to 15 µmol/l lower for south asian females) [30] . similarly, in singapore, malays and asian indians were found to have significantly lower vitamin c status than chinese (up to 12 µmol/l for females) [26] . studies in uganda, south africa, and nigeria all showed high rates of deficiency in predominately black africans [3] . socioeconomic status affects diet quality as foods of higher quality and higher nutritional value generally cost more [75] . therefore, it is not surprising that numerous studies have shown that lower socioeconomic status and deprivation negatively impact on vitamin c status ( table 2 ). in a uk study, mccall et al. [28] reported that those who were most deprived (based on the townsend deprivation index) had a two-fold odds ratio of vitamin c deficiency relative to those with plasma values above 28 µmol/l. this finding was supported by mosdol et al. [19] , who specifically focused on the low-income population within the uk, and showed a higher prevalence of deficiency and insufficiency than has been reported for the general uk population. bates et al. [41] reported a three-fold difference in plasma vitamin c status for people of low socioeconomic status in the uk relative to those of higher status. a two-fold difference in vitamin c intake between the two socioeconomic groups likely contributed to the observed differences in vitamin c status. other more recent surveys have confirmed the association of low vitamin c status with low socioeconomic status [15, 43] . the british national diet and nutrition survey indicated a 2 µmol/l increase in vitamin c status in adults for every additional £10,000 of income [44] . similar findings have been reported for the level of education, with the lowest level of education associated with the lowest vitamin c status [14, 17] . mccall et al. [28] reported that those with the lowest level of education in the uk had a 4.5-fold odds ratio of deficiency relative to a vitamin c status of >28 µmol/l. the same authors investigated social class and found that those having manual occupations had a three-fold odds ratio of deficiency compared with those having nonmanual occupations [28] . similar findings were reported by wreiden et al. [20] , with two-to three-fold higher prevalence of vitamin c deficiency for females and males, respectively, with manual occupations. one survey of elderly people assessed institutionalized individuals relative to free-living individuals [41] . the authors found significantly lower vitamin c status (25 vs. 44 µmol/l) and a higher prevalence of deficiency (40% vs. 14%) in institutionalized elderly compared with free-living elderly, respectively. much of this is likely due to a higher proportion of individuals consuming less than the recommended nutrient intake for vitamin c in institutional settings [41] . this will become a growing concern with an increasingly aging population. other institutionalized individuals, e.g., priests, prisoners, and boarding school children, have also been found to have lower vitamin c status, and higher hypovitaminosis c and severe deficiency, compared to control groups [46] [47] [48] . bodyweight and the related bmi, waist circumference, or waist-to-hip ratio are well known to have a significant association with vitamin c status (table 5) . numerous studies have shown an inverse association between body weight or bmi and vitamin c status, with obese individuals having the lowest vitamin c status [14] [15] [16] 29, 30, 67, 76] . schleicher et al. [15] reported up to a 15 µmol/l difference in the vitamin c status of obese women compared with women of healthy weight (i.e., 45 versus 60 µmol/l, respectively). pearson et al. [43] found that individuals with hypovitaminosis c (i.e., <23 µmol/l) had significantly higher weight, bmi, and waist circumference. lower vitamin c status in those of the highest weight could be partly due to lower dietary intake of the vitamin [76, 77] . in support of this, lower vitamin c status was found in those with the highest fat intake [23] . it has also been suggested that the observed differences in vitamin c status could be a result of volumetric dilution due to differences in fat-free mass [29] . this premise is supported by supplementation studies that have indicated that individuals with higher body weight do not replete as readily as those of normal body weight [78, 79] . based on these observations, block et al. [78] proposed that recommended vitamin c intakes should be based on a dose per kg body weight or in terms of an ideal plasma concentration. this is a prudent recommendation considering the ongoing increase in body weight globally, with the prevalence of obesity exceeding 50% in some countries [80, 81] . obesity is a risk factor for numerous diseases, particularly cardiometabolic diseases, such as diabetes and cardiovascular disease, which are also associated with lower vitamin c status and a higher prevalence of deficiency [9] . enhanced dietary fat and sugar, which are risk factors for cardiometabolic diseases, are also associated with decreased vitamin c intake and status [22, 23] . table 5 . health aspects that affect vitamin c status. bodyweight, bmi individuals with higher body weight or bmi have lower vitamin c status; this is likely partly due to a volumetric dilution effect. [14] [15] [16] 24, 29, 30, 43, 67, 76, 77, 82, 83] physical activity physical activity level positively correlates with vitamin c status, with inactive individuals having a 3-fold odds ratio of deficiency; this is likely partly due to associated lifestyle factors such as diet and body weight. [28, 29] pregnancy and lactation pregnancy is associated with lower vitamin c status; this is partly due to hemodilution and active transfer of vitamin c to the developing fetus and growing infant via breastmilk. [34] polymorphisms in the genes for the vitamin c transporter (svct1) and haptoglobin (hp2-2) are associated with lower vitamin c status; the latter is thought to be due to enhanced oxidative stress. [6, 45, [84] [85] [86] [87] smoking smokers have lower vitamin c status and a higher prevalence of deficiency than nonsmokers; this is partly due to enhanced oxidative stress. [14] [15] [16] 19, 20, 24, [28] [29] [30] 43, 45, 50, 53, 54, 67, 71, [88] [89] [90] [91] disease states various communicable and noncommunicable diseases are associated with lower vitamin c status; this is partly due to inflammatory processes and enhanced oxidative stress. [9,92-94] pregnant women typically have lower vitamin c status compared with nonpregnant women [34] . this is most likely due to hemodilution, as well as active transfer of the vitamin to the developing fetus [95] . women with complications of pregnancy can have even lower vitamin c status [34, 96] . supplementation of pregnant women with vitamin c can potentially decrease the risk of some pregnancy-related complications [97] . studies in high-income countries, which included women with normal vitamin c status, have failed to show benefit from supplementation [98] . however, studies in low-income settings with high rates of vitamin deficiency show potential benefits, including decreased rates of low birth weight, decreased hospital admissions, and possible decreased rates of pre-eclampsia [99] . it is noteworthy that the recently discovered epigenetic regulatory activities of vitamin c could have important roles to play in fetal development [100] . an animal model has indicated that maternal vitamin c can regulate the reprogramming of dna methylation and germline development [101] . it is likely that lactating women also have lower vitamin c status due to the transfer of vitamin c to the growing infant via breastmilk. many global authorities have taken the enhanced requirements of pregnant and lactating women into consideration, with recommendations above their standard dietary recommendations of +10-20 mg/d for pregnant women and +20-60 mg/d for lactating women [13] . vitamin c status can potentially be influenced by genetic variants. the slc23a1 gene encodes the sodium-dependent vitamin c transporter-1 (svct1), which is responsible for active uptake of dietary vitamin c through the intestinal epithelium and reuptake of filtered vitamin c via the kidney tubules and is essential in vitamin c-requiring animals [4, 6] . a number of single nucleotide variants have been identified in the slc23a1 gene, and modeling of in vitro data for four of these variants indicates 40% to 75% decreases in vitamin c uptake [6, 102] . these variants are relatively common in those of african descent (6-16%), and the variant with the largest decrease in vitamin c transport has a high prevalence in african americans [6] . meta-analysis has indicated a strong association of another of these variants with decreased vitamin c status in five cohorts in the uk (frequency of~3%) [45] . in the british women's heart and health study, a further two variants, with relatively common frequencies of~30%, were also found to be associated with vitamin c status [45] . cahill et al. [84] reported that variants of svct1 can also modify the strength of the correlation between dietary vitamin c and serum vitamin c. vitamin c status could be further influenced by genetic variants affecting the metabolism of the vitamin [103] . a common variant of the hemoglobin-binding protein haptoglobin (hp2-2) has a decreased ability to bind hemoglobin and results in increased oxidation of vitamin c in vitro [85] . several studies have shown that this variant is associated with lower circulating vitamin c concentrations [85] [86] [87] . the hp2-2 variant appeared to have a greater effect on individuals with dietary vitamin c intakes <90 mg/day [84] . it is noteworthy that genetic variants can show marked geographical differences; e.g., hp2-2 is present in~36% northwest europeans, 51% iranians, 55% thais and chinese, and 84% indians (where it is thought to have originated) [104] . other genetic variants, such as those of the detoxifying enzyme glutathione s-transferase, may also have associations with vitamin c status, particularly in individuals with lower intakes, thereby resulting in an increased risk of deficiency [105] . high-dose vitamin supplementation has been shown to ameliorate certain gene variant defects [106] and is hypothesized to occur with vitamin c-related variants [107] . therefore, individuals with genetic variants affecting vitamin c status may require higher dietary intakes. smoking is a well-known source of oxidants and in vivo oxidative stress [108] . multiple studies have shown depleted vitamin c status and a higher prevalence of deficiency in smokers compared with nonsmokers (table 5) . mccall et al. [28] reported that current smokers had over a seven-fold odds ratio of deficiency compared with nonsmokers, and wrieden et al. [20] showed two-to three-fold more deficiency in male and female smokers, respectively. smokers tended to have dietary intakes that were lower in vitamin c, e.g., lower fruit and vegetable intake and higher fat intake [88, 89, 109, 110] . however, when differences in dietary intake were taken into account, smokers still exhibited lower vitamin c status and higher requirements than nonsmokers [88, 89, 111, 112] . kallner et al. [113] demonstrated over a 40% increase in vitamin c turnover in smokers compared with nonsmokers. a few international regulatory authorities have taken the enhanced requirements of smokers into consideration with additional intake recommendations of 20 to 80 mg/d above their normal adult recommendations [13] . however, it is likely that these additional intakes are insufficient to compensate for the enhanced requirements of smokers [90] . furthermore, some countries continue to show an increasing trend in smoking rates, which could potentially impact their population's vitamin c status and requirements [114] . of note, smoking cessation results in an increase in vitamin c status [115] . vitamin c status can be depleted by various disease states due to inflammatory processes and enhanced oxidative stress (reviewed in [9, 92, 93] ). a number of studies of hospitalized patients showed a high prevalence of depleted plasma vitamin c status, and concentrations were inversely correlated with inflammatory markers [116] [117] [118] [119] . a wide range of medical conditions are associated with vitamin c insufficiency; these include noncommunicable diseases such as cardiovascular diseases (e.g., strokes, coronary artery disease and hypertension), congestive heart failure, malignancy, chronic inflammatory states (e.g., rheumatoid arthritis), metabolic disorders (e.g., diabetes), and cataracts [9, 92, 93] . acute infectious diseases leading to enhanced inflammation are also associated with depleted plasma vitamin c concentrations in plasma and immune cells, as are a range of chronic infections such as hiv, helicobacter pylori, and tuberculosis, which are prevalent in many lmics [94, 120] . it should also be noted that requirements for vitamin c during infections increase with the severity of the infection, requiring significantly enhanced intakes to reach normal plasma status [94] . this is particularly pertinent to the current global coronavirus (sars-cov-2) pandemic, which causes severe pneumonia and sepsis, conditions known to be associated with significantly depleted vitamin c status [121, 122] . it should also be noted that individuals with marginal vitamin c status are at higher risk of developing vitamin c deficiency [123] , and once depleted, higher than recommended intakes of the vitamin are required to fully replete them again [78, 79] . various factors have changed over time that could potentially affect vitamin c status. these include population demographics and health status, e.g., obesity and smoking rates. public health policies, such as recommended dietary intakes for vitamin c, have changed in many countries [13] . therefore, have these temporal changes been reflected in changing vitamin c status over time? there have been relatively few studies that have assessed vitamin c status in the same populations or regions over time. the findings can also be complicated by changes in analytical methodologies over time. two surveys have been carried out 19 years apart on elderly people in britain: one in 1979 by the department of health and social security, and the national diet and nutrition survey in 1998 [41] . there was an increase in vitamin c status from 29 to 44 µmol/l between the two surveys. however, it should be noted that participants in the first survey were older and analytical methodologies may have varied between the two surveys. in contrast, the more recent national diet and nutrition surveys (2008-2017) have shown a significant 6% increase in vitamin c deficiency over the nine-year period in women aged 19-64 [44] . schleicher et al. [15] carried out an indepth comparison of us vitamin c status in nhanes iv (2003) (2004) relative to nhanes iii that was undertaken 10-15 years earlier (i.e., 1988-1994) [124] . for those aged ≥20 years, overall vitamin c deficiency decreased by about 44% (from 15% to 8%) between the two surveys. of note, there was an increase in the recommended dietary intake for vitamin c in the us in 2000, from 60 to 90 mg/d for men and to 75 mg/d for women [125] . however, it is unlikely that this increase in dietary recommendations fully accounts for the decrease in vitamin c deficiency over time as there were also some differences in methodology between the two surveys, with the more recent survey likely being more accurate [15] . looking back even earlier to the nhanes ii survey (carried out between 1976 and 1980), vitamin c status was reported to be higher for both men and women (i.e., ≥50 µmol/l for men and ≥60 µmol/l for women), with 5% deficiency reported, despite lower dietary intakes compared to the later nhanes iii survey [126] . it should be noted, however, that vitamin c in the nhanes ii samples was analyzed using the 2,4-dinitrophenylhydrazine method, which can be prone to interference by other components in plasma and thus potentially overestimate vitamin c concentrations [127] . other time course data is available from studies carried out in finland and neighboring russia between 1992 and 2002 [17, 51] . in north karelia, finland, the vitamin c status of men decreased from 54 to 27 µmol/l over 5 years, then rose slightly to 37 µmol/l over the next 5 year period [17] . nyyssonen et al. reported a small increase in baseline vitamin c values in finish men over 6 years [72] . in pitkäranta, russia, the vitamin c status of women decreased from 22 to 13 µmol/l over a 5-year period, while the vitamin c status of russian men remained in the deficiency range over a 10-year period [17] . the blood samples from the more recent survey (2002) were from fasting participants; however, it is not clear whether they were fasting in the earlier surveys (1992 and 1997). another set of studies was carried out in java, indonesia, between 2005 and 2011 [128, 129] . mean vitamin c status decreased in the subjects from 45 to 29 µmol/l over 6 years, although the percentage of deficiency decreased from 15% to 11% over this time. the decrease in mean vitamin c status could partly be explained by the earlier study assessing nonfasting plasma (as demonstrated by a higher percentage of vitamin c status >23 µmol/l, i.e., 72% versus 54%). however, there are possibly other environmental, lifestyle, or health-related issues that could be responsible for the changes in vitamin c status over time in indonesia, finland, and russia. not all studies have shown changes in vitamin c status over time. a survey carried out in shanghai, china, over a five-year period (between 1995 and 2000) showed no change in vitamin c status over this time period, although there was a dip in status at the midpoint (from 43 to 34 µmol/l) [52] . thus, there is currently no clear trend in vitamin c status over time. however, much of the vitamin c data is very dated, and thus may not accurately reflect the current situation, particularly in countries where there have been changes over time in specific factors that can affect vitamin c status. this narrative review describes the findings of numerous studies which highlight the various factors that can impact on vitamin c status and prevalence of deficiency. the studies were of variable quality; ideally, multivariate analysis of the various factors highlighted in these studies would be performed to further examine the relationships discussed. another limitation is the variable quality of the processes and methodologies used to assess vitamin c status in the studies; this has been addressed in detail in our review on global vitamin c status [3] . global vitamin c status appears to be a cause for concern, and we believe this is primarily due to poor diet, particularly in lmics, although also apparent in subgroups within high-income settings [3] . vitamin c concentrations provide a useful biomarker for a healthy diet; unfortunately, accurate analysis is costly, technically challenging, and time-consuming [130] . thus, there is a need for low cost, accurate, and commercially available methods to assess plasma concentrations. equally, the current assessment of intake is also limited and fails to take into account that the vitamin may be almost entirely eliminated prior to consumption in some globally important crops, such as cassava [38] . future amendments to nutrient reference tables should take into this aspect into account. clearly, there is a global need for increased consumption of vitamin-c-rich fresh fruit and vegetables. from our earlier review, this appears to be most notable in lmic's; however, it is also a concern in other at-risk groups [3] . further education is required globally in how to meet the daily vitamin c requirements with locally available crops year-round. some staple foods such as cassava require prolonged cooking to remove toxins (in this case, cyanide); efforts have been made to reduce this content in genetically modified cassava, which could allow higher vitamin c content from this vitamin-rich plant at the time of consumption [38] . given the high rates of deficiency in some diets, cooking practices may also require modification to help increase intake. a number of studies have assessed the potential for vitamin c supplements to reduce a range of noncommunicable diseases and infections [9, 94] . however, there remains much controversy as to the efficacy of supplementation, primarily due to badly designed studies that do not take into account the baseline vitamin c status of the participants [98] . therefore, knowledge of the high-risk groups for deficiency should be utilized for future studies as these groups are more likely to benefit from 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acid key: cord-324288-qgxswltx authors: padhi, sunali; suvankar, subham; panda, venketesh k.; pati, abhijit; panda, aditya k title: lower levels of vitamin d are associated with sars-cov-2 infection and mortality in the indian population: an observational study date: 2020-09-14 journal: int immunopharmacol doi: 10.1016/j.intimp.2020.107001 sha: doc_id: 324288 cord_uid: qgxswltx background: the role of vitamin d in the susceptibility and severity of various viral diseases has been well documented. recently, some reports highlighted the possible importance of vitamin d in severe acute respiratory syndrome coronavirus 2 (sars-cov-2). although india receives adequate sunlight throughout the year, the majority of indians are deficient in vitamin d levels. in the present study, we hypothesized that vitamin d deficiency would be associated with the sars-cov-2 infection rate and mortality in the indian population. materials and methods: sars-cov-2 infection and mortality data were obtained from the government of india's official website (accessed on 16(th) august 2020). various literature databases like pubmed and google scholar were searched to find the mean of 25-hydroxyvitamin d [25(oh)d] levels in different states and union territories of india, pearson correlation was carried out to investigate the possible link between mean 25(oh)d levels and sars-cov-2 infection and mortality per million of the population. results: an inverse correlation was observed between the mean level of 25(oh)d and sars-cov-2 infection rate (r= -0.43, p= 0.02) and mortality rate (r= -0.42, p= 0.02). conclusions: the present observational study revealed an association of vitamin d with sars-cov-2 infection and related mortality. further studies are required to validate our observations. novel coronavirus disease 2019 caused by severe acute respiratory syndrome coronavirus 2 (sars-cov-2) was first reported in wuhan, china, in december 2019 [1] and has spread worldwide to 215 countries till date (https://www.worldometers.info/coronavirus/). on 11th march 2020, covid-19 disease was declared a global pandemic by the world health organization (who)(https://www.who.int/dg/speeches/detail/who-director-general-s-openingremarks-at-the-media-briefing-on-covid-19---11-march-2020). india reported the first case of covid-19 in a student who returned from wuhan university china in thrissur district of kerala state on 30 th january 2020 (https://www.cnbc.com/2020/01/30/india-confirms-first-case-of-thecoronavirus.html). as on 16 th august 2020, 2.59 million of sars-cov-2 infected cases has been reported in india, and a total of 50,431 death has been encountered. maharashtra and tamil nadu states contributed the maximum number of infected cases and posed a high mortality of sars-cov-2 infected patients in india. individual immune systems, which are determined by several factors, play a major role in the susceptibility and pathogenesis of viral diseases. the importance of vitamin d in the modulation of both innate and adaptive immune systems has been demonstrated [2] . in the skin, provitamin d 3 (7-dehydrocholesterol) is converted to previtamin d 3 after exposure to ultraviolet-b (uvb) radition. the previtamin d 3 is transported to the liver and hydroxylated at 25 th carbon atom. the active metabolites 1,25(oh) vitamin d 3 is hydroxylated for the second time at c-1 at the kidneys [3] . furthermore, 1-hydroxylation of vitamin d 3 is also reported in macrophages, monocytes, b and t lymphocytes [4] .vitamin d deficiency has been associated with susceptibility to a wide range of viral infections, such as human immunodeficiency virus, influenza virus, epstein -barr virus, hepatitis b, human respiratory syncytial virus [5] . however, the role of vitamin d in sars-cov-2 infection is not well understood. some recent investigations have highlighted the beneficial role of vitamin d against sars-cov-2 infection and related clinical severity [6] [7] [8] [9] [10] [11] [12] [13] , by modulating the immune system [14] . in addition, a recent study in uk population reported the worst morbidity outcome in older patients with vitamin d deficiency [13] . although india is close to the equator and receives a large amount of sunlight throughout the year, most of the indian population (50-90%) is deficient in vitamin d [15] . in addition, we investigated the correlation between vitamin d and covid-19 disease in the indian population to minimize the effect of various confounding factors such as ethnicity, latitude, health facility, etc. india is comprised of twenty-eight states and eight union territories (uts) and estimated inhabitants of 1380 million equivalent to 17.7% of the total world population. vitamin d levels in healthy adults were searched through pubmed and google scholar in the indian population. all relevant articles were screened, and data such as the author's name, year of publication, number of healthy subjects enrolled for the analysis, mean ± standard deviation or median, interquartile range of vitamin d were extracted. sars-cov-2 data such as the number of cases, death figures, and the number of recovered persons were obtained from the official website of the ministry of health and family welfare, govt. of india (www.mohfw.gov.in accessed on 16/08/2020). the population of each state and uts were gathered from data of census performed in the year 2011 (https://censusindia.gov.in/2011common/censusdata2011.html). sars-cov-2 cases per million and death per million were calculated by using the census-2011 data. based on suggestions how to present numerical data appropriately [16] , the infection rate per million were converted into multiples of ten. dearth rate and mean vitamin d levels were represented in whole numbers. data on levels of 25(oh)d in the median and interquartile range were converted in to mean ± standard deviation format as described earlier [17] . the mean 25(oh)d levels in a state or ut with more than one report were pooled (https://home.ubalt.edu/ntsbarsh/businessstat/otherapplets/pooled.htm). the pearson correlation test performed a correlation of mean 25(oh)d levels with sars-cov-2 infection and mortality rate. all statistical analysis was carried out by graphpad prism 8.3.0. a p-value <0.05 was considered as statistically significant. (table 1) this study is the first of its kind to investigate the association of vitamin d with sarsapril 2020) [19] . however, after updating data on 12 th may 2020, the relationship was disappeared [21] . further, a recent report highlighted a higher chance of sars-cov-2 infected patients being admitted to an intensive care unit compared to those with insufficient or sufficient levels of vitamin d in the uk population [9] . the risk of hospitalization in sars-cov-2 infected subjects with lower levels of 25(oh)d was higher in the israeli cohort [7] . a recent analysis revealed lower mortality rates of covid-19 in the equatorial region compared to geographical areas away from the equatorial line [22] , as confounding factors for sars-cov-2 related death [23] . severe vitamin d deficiencies have been associated with those confounding diseases such as ckd [24] , copd [25] , cerebrovascular disease [26] , and chd [27] . although several clinical trials have been registered to investigate the role of vitamin d supplementation in the treatment of sars-cov-2 patients (https:/clinicaltrials.gov/ct2/results?cond=covid19&term=vitamin+d&cntry=&state=&city=&dis t=) majority of these trials are in the enrolment phase or have yet to be started. a recent study has shown that the administration of 1000 iu of vitamin d per day to four patients infected with sars-cov-2 leads to normalization of vitamin d levels, improved clinical condition, decreased oxygen requirements, reduced inflammatory markers, and shorter hospital stays [8] . in addition, another hospital-based randomised clinical study found that the use of calcifediol in infected sars-cov-2 subjects minimised the need for intensive care and reduced disease severity [28] . these [132] [133] [134] [135] [136] [137] [138] note: sars-cov-2 data was accessed on 16.08.2020 a new coronavirus associated with human respiratory disease in china vitamin d and the immune system vitamin d metabolism, mechanism of action, and clinical applications vitamin d3: a helpful immuno-modulator vitamin d and the anti-viral state 25-hydroxyvitamin d concentrations are lower in patients with positive pcr for sars-cov-2 low plasma 25(oh) vitamin d level is associated with increased risk of covid-19 infection: an israeli population-based study vitamin d supplementation in covid-19 patients: a clinical case series low serum 25-hydroxyvitamin d (25[oh]d) levels in patients hospitalized with covid-19 are associated with greater disease severity serum calcium as a biomarker of clinical severity and prognosis in patients with coronavirus disease vitamin d and covid-19: from potential therapeutic effects to unanswered questions vitamin d deficiency as a predictor of poor prognosis in patients with acute respiratory failure due to covid-19 association of vitamin d status and other clinical characteristics with covid-19 test results the importance of vitamin d metabolism as a potential prophylactic, immunoregulatory and neuroprotective 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risk of cardiovascular disease effect of calcifediol treatment and best available therapy versus best available therapy on intensive care unit admission and mortality among patients hospitalized for covid-19: a pilot randomized clinical study seasonal variations in serum 25-hydroxy vitamin d levels in a swedish cohort seasonal, ethnic and gender variations in serum vitamin d3 levels in the local population of peterborough association between low vitamin d and covid-19: don't forget the vitamin d binding protein high prevalence of low dietary calcium, high phytate consumption, and vitamin d deficiency in healthy south indians vitamin d status in primary hyperparathyroidism in india vitamin d status and bone mineral density in women of reproductive and postmenopausal age groups: a cross-sectional study from south india high prevalence of low dietary calcium and low vitamin d status in healthy south indians vitamin d in epilepsy: vitamin d levels in epilepsy patients, patients on antiepileptic drug polytherapy and drug-resistant epilepsy sufferers a study of serum vitamin d in psoriatic patients in a tertiary care hospital of assam status of 25(oh)d levels in pregnancy: a study from the north eastern part of india a study on the biological reference interval of vitamin d in north-east india evaluation of calcium, phosphorus and vitamin d level in different stages of pregnancy in east indian population bioavailable vitamin d levels are reduced and correlate with bone mineral density and markers of mineral metabolism in adults with nephrotic syndrome high prevalence of vitamin d deficiency in north indian adults is exacerbated in those with chronic kidney disease correlation of vitamin d and vitamin d receptor expression in patients with alopecia areata: a clinical paradigm vitamin d status and risk of ischemic stroke in north indian patients vitamin d status and its seasonal variability in healthy young adults in an asian indian urban population, endocrine practice : official journal of the american college of endocrinology and the american association of relationship between preeclampsia and vitamin d deficiency: a case control study blood lead levels in occupationally exposed workers involved in battery factories of delhi-ncr region: effect on vitamin d and calcium metabolism status of vitamin d and the associated host factors in pulmonary tuberculosis patients and their household contacts: a cross sectional study peak bone mineral density of physically active healthy indian men with adequate nutrition and no known current constraints to bone mineralization vitamin d status and risk of stroke: the rotterdam study vitamin d insufficiency is associated with abdominal obesity in urban asian indians without diabetes in north india prevalence and functional significance of 25-hydroxyvitamin d deficiency and vitamin d receptor gene polymorphisms in asian indians prevalence and significance of low 25-hydroxyvitamin d concentrations in healthy subjects in delhi presence of 25(oh) d deficiency in a rural north indian village despite abundant sunshine bone mineral parameters in healthy young indian adults with optimal vitamin d availability effect of two different doses of oral cholecalciferol supplementation on serum 25-hydroxy-vitamin d levels in healthy indian postmenopausal women: a randomized controlled trial vitamin d and insulin resistance in postmenopausal indian women a double-blind, randomized, placebo-controlled trial of the shortterm effect of vitamin d3 supplementation on insulin sensitivity in apparently healthy, middle-aged, centrally obese men, diabetic medicine : a journal of the prevalence of vitamin d deficiency and its relationship with thyroid autoimmunity in asian indians: a community-based survey levels of 25-hydroxy vitamin d3 and vitamin d receptor polymorphism in severe dengue cases from new delhi risk and outcome of multidrug-resistant tuberculosis: vitamin d receptor polymorphisms and serum 25(oh)d, the international journal of tuberculosis and lung disease : the official journal of the international union against relationship of levels of vitamin d with flow-mediated dilatation of brachial artery in patients of myocardial infarction and healthy control: a casecontrol study level of vitamin d in hypothyroid subjects: a study on the suburban population of north-west delhi osteoporosis international : a journal established as result of cooperation between the european foundation for osteoporosis and the absence of vitamin d deficiency among common outdoor workers in delhi independent association of severe vitamin d deficiency as a risk of acute myocardial infarction in indians vdr polymorphism, gene expression and vitamin d levels in leprosy patients from north indian population profile of vitamin d in patients attending at general hospital mahad india serum magnesium and vitamin d levels as indicators of asthma severity, pulmonary medicine 2016 vitamin d deficiency in patients with chronic tension-type headache: a case-control study vitamin d deficiency in healthy postmenopausal women in haryana correlation of vitamin d levels with pigmentation in vitiligo patients treated with nbuvb therapy current scenario of prevalence of vitamin d deficiency in ostensibly healthy indian population: a hospital based retrospective study vitamin d status in cold trans-himalayan deserts at altitude of 4000 meter and above in india pattern of 25 hydroxy vitamin d status in north indian people with newly detected type 2 diabetes: a prospective case control study serum vitamin d levels and alopecia areata-a hospital based case-control study from north-india vitamin d status in apparently healthy adults in kashmir valley of indian subcontinent prevalence of vitamin d deficiency among indian menopausal women and its correlation with diabetes: a first indian cross sectional data combinatorial effect of leptin, tumor necrosis factor-αlpha, and vitamin d in progression of type 2 diabetes in kashmiri population vitamin d(3) level in women with uterine fibroid: an observational study in eastern indian population vitamin d status, hypertension and ischemic stroke: a clinical perspective serum vitamin d(3) levels and diffuse hair fall among the student population in south india: a case-control study low levels of serum vitamin d in chronic periodontitis patients with type 2 diabetes mellitus: a hospital-based crosssectional clinical study tuberculosis and vitamin d deficiency vitamin d status in hypertension vitamin d levels in depressive disorder association of vitamin d deficiency and hypothyroidism in a tertiary teaching hospital in kerala comparative study of serum vitamin d levels and other biomarkers in patients attending tertiary cardiac care center duration of casual sunlight exposure necessary for adequate vitamin d status in indian men vitamin d status and gestational diabetes mellitus relationship of lipid parameters with bone mineral density in indian population low bone mass in urban indian women above 40 years of age: prevalence and risk factors study of bone mineral density in resident doctors working at a teaching hospital peak bone mineral density and its determinants in an asian indian population study of vitamin d levels and its correlation with insulin resistance vitamin d as a marker of cognitive decline in elderly indian population vitamin d deficiency : highly prevalent among apparently healthy female adolescents in both urban and rural population of manipur vitamin d status and its relationship with systemic lupus erythematosus as a determinant and outcome of disease activity evaluation of vitamin d status and its impact on thyroid related parameters in new onset graves' disease-a crosssectional observational study vitamin d status in adult critically ill patients in eastern india: an observational retrospective study evaluation of vitamin d status in urban population employed in office jobs evaluation of serum 25 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urban population of malwa region of punjab association of deficiency of maternal vitamin d levels with severity of preeclampsia role of vitamin d and risk of prostate cancer serum 25-hydroxy vitamin d, calcium,phosphorus and alkaline phosphatase levels in healthy adults above the age of 20 living in potheri village of kancheepuram district osteoporosis in healthy south indian males and the influence of life style factors and vitamin d status on bone mineral density prevalence of osteoporosis in ambulatory postmenopausal women from a semiurban region in southern india: relationship to calcium nutrition and vitamin d status, endocrine practice : official journal of the american college of endocrinology and the vitamin d deficiency and insulin resistance in normal and type 2 diabetes subjects 25 (oh) vitamin d level in crohn's disease : association with sun exposure & disease activity correlation of vitamin-d levels with blood sugar levels in diabetes mellitus bone mass of overweight affluent indian youth and its sex-specific association with body composition association of vitamin d receptor gene polymorphisms with bmd and their effect on 1, 25-dihydroxy vitamin d3 levels in pre-and postmenopausal south indian women from andhra pradesh development of non-alcoholic fatty liver disease (nafld) in young obese tribal subjects of tripura: link between low 25 (oh) vitamin-d levels and immune modulators systemic inflammation and alteration in vitamin d levels in pregnancy induced hypertension prevalence of osteoporosis in otherwise healthy indian males aged 50 years and above effect of vitamin d supplementation on bone health parameters of healthy young indian women vitamin d status and its relationship with bone mineral density in healthy asian indians, osteoporosis international : a journal established as result of cooperation between the european foundation for osteoporosis and the a study on association of degree of physical exercise and plasma 25-(oh) vitamin d levels serum 25 hydroxyvitamin d profile after single large oral doses of cholecalciferol (vitamin d3) in medical staff in north india: a pilot study comparison of calcium, phosphorous and 25 (oh)d2 levels in sedentary and labourer females vitamin d" as a profile marker for cardiovascular diseases vitamin d status among women aged 40 years and above in a rural area of west bengal: a community-based study sun exposure and vitamin d in rural india: a cross-sectional study profile of vitamin d in a cohort of physicians and diabetologists in kolkata serum vitamin-d predicts insulin resistance in individuals with prediabetes lean mass is the strongest predictor of bone mineral content in type-2 diabetes and normal individuals: an eastern india perspective assessment of vitamin d status in patients of chronic low back pain of unknown etiology prevalence of vitamin d deficiency in a pediatric hospital of eastern india key: cord-290592-c9bsielo authors: wang, rui; degruttola, victor; lei, quanhong; mayer, kenneth h.; redline, susan; hazra, aditi; mora, samia; willett, walter c.; ganmaa, davaasambuu; manson, joann e. title: the vitamin d for covid-19 (vivid) trial: a pragmatic cluster-randomized design date: 2020-10-10 journal: contemp clin trials doi: 10.1016/j.cct.2020.106176 sha: doc_id: 290592 cord_uid: c9bsielo objectives to determine the effect of vitamin d supplementation on disease progression and post-exposure prophylaxis for covid-19 infection. we hypothesize that high-dose vitamin d3 supplementation will reduce risk of hospitalization/death among those with recently diagnosed covid-19 infection and will reduce risk of covid-19 infection among their close household contacts. methods we report the rationale and design of a planned pragmatic, cluster randomized, double-blinded trial (n = 2700 in total nationwide), with 1500 newly diagnosed individuals with covid-19 infection, together with up to one close household contact each (~1200 contacts), randomized to either vitamin d3 (loading dose, then 3200 iu/day) or placebo in a 1:1 ratio and a household cluster design. the study duration is 4 weeks. the primary outcome for newly diagnosed individuals is the occurrence of hospitalization and/or mortality. key secondary outcomes include symptom severity scores among cases and changes in the infection (seroconversion) status for their close household contacts. changes in vitamin d 25(oh)d levels will be assessed and their relation to study outcomes will be explored. conclusions the proposed pragmatic trial will allow parallel testing of vitamin d3 supplementation for early treatment and post-exposure prophylaxis of covid-19. the household cluster design provides a cost-efficient approach to testing an intervention for reducing rates of hospitalization and/or mortality in newly diagnosed cases and preventing infection among their close household contacts. keywords: vitamin d, covid-19, sars-cov-2, early treatment, prophylaxis, cluster randomization coronavirus disease , caused by the novel severe acute respiratory syndrome coronavirus 2 (sars-cov-2), presents a major threat to human health [1] . sars-cov-2 is highly infectious, associated with extensive morbidity and mortality, and household contacts of infected patients and healthcare personnel are at particularly high risk for infection [2] . as diagnoses and deaths continue to rise worldwide, covid-19 is now widely recognized as a global pandemic. given this public health crisis, there is a critical need to have quickly deployable and efficient randomized trials to test promising treatments and prophylactic interventions to slow the pandemic. development of pragmatic, adaptive, and cost-efficient trials is a high priority. in this setting, we identified vitamin d supplementation as a promising intervention to test. as described below and summarized in the table, several lines of evidence suggest that vitamin d deficiency is a risk factor for covid-19 and that improvement in vitamin d status by supplementation may mitigate covid-19 risk for clinical progression. laboratory studies demonstrate that vitamin d is active in pathways relevant to immune function, stimulating the expression of vitamin d receptors in both the innate and the adaptive immune systems. vitamin d metabolites support innate immune responses to several viruses in cultured human respiratory epithelial cells [3] [4] [5] [6] [7] , including rhinovirus and respiratory syncytial j o u r n a l p r e -p r o o f virus (rsv). vitamin d may reduce the burden of infections by lowering viral replication rates, through the induction of antimicrobial peptides [8] [9] [10] and by enhancing cellular immunity by reducing pro-inflammatory cytokines and increasing concentrations of anti-inflammatory cytokines [11, 12] . both epidemiological and clinical studies have shown that vitamin d, acting as an important immunomodulator, may reduce the incidence of respiratory tract infections in both adults and children [13] [14] [15] [16] [17] . randomized trials have also provided supportive evidence that vitamin d supplementation reduces risk of acute respiratory infections in these populations (22) (23) (24) . a meta-analysis of 11,321 participants in 25 randomized controlled trials of vitamin d supplementation to prevent acute respiratory tract infections (upper and lower respiratory tracts) demonstrated a protective effect of the intervention overall (12% reduction), but a particularly large magnitude of benefit (70% reduction) from supplementation in those with profound vitamin d deficiency at baseline [18] . however, results showed heterogeneity, with strong protective effects in some trials [19] [20] [21] and others with null findings [22, 23] . this heterogeneity may reflect two factors: i) variation in dose of vitamin d administered: some trials gave a low dose of ≤400 iu per day, and ii) variation in participant characteristics: strongest protection effects against acute respiratory tract infection were seen among those with vitamin d deficiency at baseline. given that sars-cov-2 is a novel virus, the potential role of vitamin d in affording protection against this specific infection is promising but unknown. covid-19 patients with weakened innate immune systems may be susceptible to more severe symptoms and higher mortality [24] . an impaired host immune system response may lead to higher sars-cov-2 viral load and subsequent overactivation of the adaptive immune system j o u r n a l p r e -p r o o f that results in cytokine release syndrome [25, 26] . vitamin d can modulate both the innate and adaptive immune responses [27] and suppress the hyperinflammatory response during infection [33] . ecologic and demographic data also provide support for a protective role of vitamin d studies [28, 29] . inverse correlations between mean levels of vitamin d in each of 20 european countries and the rates of covid-19 diagnoses and mortality have been observed [30] . demographic groups known to be at elevated risk for vitamin d insufficiency-black or hispanic individuals, the elderly, nursing-home residents, and those with obesity, vascular comorbidities, or chronic kidney disease-are also those at higher risk of covid-19 hospitalization and/or mortality [31] . finally, several observational studies have shown a significant association between a low serum 25(oh)d level status and worse clinical outcomes of covid-19 patients [32] [33] [34] . the vitamin d for covid-19 (vivid) trial is a pragmatic, cluster-randomized, placebocontrolled, double-blind trial to evaluate the efficacy of vitamin d3 supplementation with 3200 iu/d daily for 4 weeks to reduce disease severity in persons with newly diagnosed covid-19 infection and to prevent infection in their closest household members. in this article, we detail the rationale and design of this nationwide study that is in development and is subject to adaptive changes as needed. j o u r n a l p r e -p r o o f vivid is based on a parallel group design (n=2700 in total nationwide); the study population includes 1500 newly diagnosed individuals (referred to as "index cases") as well as the closest household contacts of each index if such a person is identified and consents (~1200 in total). each participant-whether index or contact-is randomized to either vitamin d3 or placebo in a 1:1 ratio in a household "cluster" design. the study duration for each participant is 4 weeks. the infected individuals will be followed to assess disease progression defined as the need for hospitalization and/or mortality. their household members will be followed to assess infection status, either progression if seropositive at baseline, or seroconversion, if uninfected at baseline. a schematic of the design is displayed in the figure, where vertical arrows show time sequences and horizontal arrows show randomization which will be done prior to covid diagnostic testing for the household members, due to concerns regarding delays in receiving the contact"s test results and the need to start treatment early. subsequent events apply to both randomized groups. if the treatment works for both the early-treatment and prophylaxis cohorts, then this earlyintervention approach could be implemented in practice. the primary hypothesis is that vitamin d3 supplementation will reduce the risk of hospitalization and/or mortality among patients who are newly diagnosed with covid-19 infection but do not require hospitalization at baseline. the primary outcome is the occurrence of hospitalization and/or mortality. hospitalizations and deaths will be confirmed by chart review or interview of next of kin. j o u r n a l p r e -p r o o f for index cases: • vitamin d3 supplementation will reduce self-reported disease severity over 4 weeks. participants will self-report symptom severity and disease progression on weekly questionnaires: for each specified covid-19 related symptoms (fever or chills, cough, shortness of breath or difficulty breathing, fatigue, muscle or body aches, headache, new loss of taste or smell, sore throat, congestion or runny nose, nausea or vomiting, diarrhea), participants will report one of the following 3 options: absence (score of 0), mild/moderate (score of 1), severe (score of 2). the total disease severity score will be the average across all potential symptoms. • vitamin d3 supplementation will delay time to hospitalization/mortality. vitamin d3 supplementation will reduce the risk of icu admission/ventilation support in index cases. for the closest household contacts of index cases: • vitamin d3 supplementation will prevent sars-cov-2 infection(seroconversion). • vitamin d3 supplementation will reduce self-reported total disease severity defined in the same way as for the index participants. the study population will include individuals who tested positive for covid-19 infection within 72 hours of the covid diagnostic testing and have experienced covid-19 related symptoms j o u r n a l p r e -p r o o f for no longer than 4 days (for the "index cases"), and the closest cohabiting contact, if such a person is identified and consents, for each newly diagnosed individual. for all participants, the ability to understand and provide informed consents, and to complete online questionnaire, and not participating in other covid-19 trials are required. for index cases, we will target a high-risk study population defined by adults ≥30 years of age for household members, we plan to recruit the closest contact, age 18 or older, living in the same household as the index case. exclusion criteria that differ from the index individuals are: 1) history of sars-cov-2 diagnosis or onset of symptoms more than 5 days before study entry; and 2) receipt of a sars-cov-2 vaccination or monoclonal antibody. eligible index cases and their household contacts will be randomly assigned, in a cluster fashion, to one of the two study groups in a 1:1 ratio using a permuted block design (block size of 8), via a web-based randomization module after the index signs the informed consent. intervention: daily oral softgel capsule containing 3200 iu vitamin d3 (with a loading dose of 9600 iu/day for day 1 and day 2), administered daily for 4 weeks. participants will be mailed a supply of pills by an overnight courier service (due to the time sensitivity) and instructed to take 3 pills each day for the first two days and 1 pill daily thereafter. control: daily oral placebo capsule of identical appearance and taste containing no vitamin d. recruitment. participants will be recruited nation-wide via social media; community advocacy groups and equity initiatives; flyers and electronic communications distributed in healthcare centers, low income residential housing organizations, covid-19 testing centers, and other avenues. all recruitment will be conducted remotely and prospective participants will be asked to baseline and follow-up: blood samples will be collected for all participants at baseline and at 4week follow-up. the blood microsampling collection kit will be mailed to participants" home and will be returned through postal mail. the blood sample will be used for testing of 25hydroxyvitamin d (25ohd) level as a marker of vitamin d status. for household members, week 4 samples will be tested for sars-cov-2 antibody positivity. for those who test positive at week 4, the baseline sample will also be tested to confirm absence of infection at baseline. participants will receive a daily text message as a reminder to take study pills. they will also be instructed to complete weekly online redcap questionnaires for 4 weeks and an additional poststudy follow-up questionnaire at week 8. the questionnaire will include items on adherence with randomized treatments, use of non-trial supplements of vitamin d, use of calcium supplements, development of symptoms and new illness, dietary intakes of vitamin d, and self-report of disease progression and severity status. non-responders will be telephoned to collect study data. (additional details are in the supplement.) participants will be instructed to discontinue their study pills if, during follow-up, they receive a diagnosis of kidney stones, hypercalcemia, or other safety-exclusion conditions. participants will be advised to discontinue the study treatment if, in the course of follow-up, they report taking supplementary vitamin d (not from diet) that amounts to greater than 800 iu per day or daily calcium supplements that amount to greater than 1200 mg per day. j o u r n a l p r e -p r o o f analyses of treatment effects will be based on the intention-to-treat principle. primary analyses will follow this principle; that is, individuals will be analyzed according to their assigned treatment group, whether or not they take the study treatment as assigned. for endpoints (e.g., seroconversion) measured on individuals from the prophylaxis cohort (household members), because the study population consists of one individual from one household, the outcomes are independent and hence standard analysis methods for individual randomized trials apply. however, for endpoints (e.g., hospitalization/mortality, disease progression) measured on early treatment cohort (index cases and some of the household members who are already infected at baseline), because some of the household members may be included in the early treatment, it is necessary to take household clustering into account in the analysis. we will use the generalized estimating equations approach with robust sandwich variance [35] to properly quantify the uncertainty of the treatment effect estimates for clustered outcomes. nmol/l respectively [18] . because the study duration for each participant is only four weeks, we anticipate a low lost-to follow-up rate. recognizing that a proportion of the household contacts will already be infected at baseline and will be included in the primary analysis of early treatment cohort, the actual power will be greater and can offset power loss due to the loss to follow-up. for household contacts. assuming 80% of newly diagnosed participants will also have a close co-habiting contact enrolled into the study, we anticipate enrolling 1200 into the household contact cohort. jing et al. estimated a 12.4% secondary attack rate among household contacts [36] . in a systematic review, shah et al. found that the reported secondary attack rate of covid-19 in household contacts ranged from 4.6% to 49.6% [37] . assuming 20% of these individuals are already seropositive for covid-19 at baseline, the number of evaluable participants for the key secondary hypothesis that the household members of the infected individual will have a lower seroconversion rate is n=1000. a sample size of 500 in each j o u r n a l p r e -p r o o f comparison arm achieves 80% power to detect a 40% reduction in serological positive rate from 15% to 9% based on a fisher"s exact test. we will establish an external dsmb for the trial. given the short duration of the study, an interim meeting is planned when half of the participants have been enrolled, or at 6 months, whichever occurs earlier. at the meeting, the dsmb will assess whether study progress, data integrity and safety monitoring warrant continuation of the study and make recommendations accordingly. (additional details are in the supplement.) the coronavirus disease 2019 (covid-19) is an escalating global pandemic associated with the potential for severe respiratory complications. there is an urgent public health need for effective therapeutic and prophylactic strategies that have proven to be safe in humans-which is especially acute given the rapid spread of sars-cov-2 and lack of vaccines or highly effective treatments for infected individuals who do not require hospitalization to slow down the disease progression. to investigate the effect of vitamin d and potential alternative agents requires studies that can be completed expeditiously, conducted safely, use resources efficiently, and produce reliable results. the vivid trial will assess the effect of vitamin d supplementation for early treatment and post-exposure prophylaxis of covid-19. the study is highly pragmatic and will be conducted remotely with no study visits required, which facilitates national recruitment, limiting infection control challenges. salient features of the study include the cluster randomization design which j o u r n a l p r e -p r o o f both offers logistic convenience and avoids treatment contamination: both household members will receive the same treatment; and permits answering two important questions: early treatment and prophylaxis, in the same study. the trial is innovative in that it allows for participants in the same cluster to be in two different cohorts, which have different endpoints-while maintaining valid randomization and therefore preservation of the type i error control. the design is cost-efficient in that testing for covid-19 among household contacts need not be done until the end of the study; hence, baseline samples need only be tested for those who test seropositive at end of follow-up. the nationwide recruitment allows for nimble and targeted recruitment in geographic areas with higher infection rates ("hot spots"), the locations of which will change over time. another innovative aspect of the trial design is that enrollment of household members occurs before they are tested for covid-19. this is possible because the same agent is under study for both prophylaxis and treatment components; hence vitamin d can be initiated as quickly as possible after participants have consented to randomization. in searching for a treatment and prevention agent for covid-19, many drugs and chemical compounds are being considered (see for example, jeon et al. [38] ). the everchanging landscape of prevention policies, pandemic dynamics, and rapidly accruing knowledge requires studies to be sufficiently flexible. our study design is customizable and can be tailored to test other candidates in a rolling platform fashion [39] . it can also be extended to efficiently test two drugs at the same time through a factorial design by adding a second agent (e.g., inhaled corticosteroids). the study has limitations. first, it is possible that vitamin d blood levels would not improve rapidly enough to affect the course of the infection. although a higher loading dose (9600 iu/day) is incorporated for the first two days of the study, it may take a week or longer to eliminate vitamin d deficiency. we plan to measure vitamin d levels to better understand the trajectory of 25(oh)d increase over time in this study population. we are avoiding massive bolus dosing because it is not physiologic and has not shown benefits for reducing respiratory infections or other adverse outcomes in previous vitamin d trials [40] [41] [42] . calcifediol can more rapidly increase serum 25(oh)d level and a recent study evaluated its effect when added to best available therapy among patients hospitalized for covid-19 [43] ; future studies may be designed to assess its effect in slowing disease progression to hospitalization. second, despite considerable uncertainty regarding the role of vitamin d for the treatment and prevention of covid-19, some participants may choose to take out-of-study vitamin d supplements; vitamin d is readily available in pharmacies and stores. also, recruitment may be challenging due to unwillingness to participate in a randomized trial with a 50% chance of receiving placebo. however, our study pills will have stricter quality control monitoring than most over-the counter dietary supplements. in a recent study, leblanc et al. found that the cholecalciferol content of over-the-counter and compounded vitamins was highly variable [44] . we will provide this information to potential participants to increase the attractiveness of the study. third, the initiation of treatment is very time sensitive. due to the lag time in receiving covid test results by participants and contacting the study, it may be challenging to initiate treatment within the short time window allowed after the onset of symptoms. however, enrolling their asymptomatic close household contacts at baseline--some of whom are likely already to have been infected and j o u r n a l p r e -p r o o f will contribute information to the early treatment cohort--will improve our ability to assess the effect of vitamin d on progression when treatment begins early. in summary, this study will provide reliable randomized evidence about the effect of vitamin d on both early treatment and post-exposure prophylaxis of covid-19. the data collected from this study will also permit us to develop and validate a covid-19 symptom score for disease progression. given that covid-19 disproportionately affects race/ethnicity minority groups and high prevalence of vitamin d deficiency in these groups, vitamin d efficacy may provide opportunities for reducing health disparities. this innovative, pragmatic, and timely rct will address a critical unmet need in the prevention and clinical management of sars-cov-2 in the community. the results will be of immediate clinical relevance by providing evidence to inform measures to control the pandemic and mitigate disease occurrence and severity, as well as to reduce personal suffering, mortality, and health care costs. j o u r n a l p r e -p r o o f inclusion criteria: 1. persons ≥18 years of age who lives in the same household with the index individual and have been identified as the closest contact within the same household. 2. ability and willingness of participant to understand the study and provide informed consent. s2. informed consent procedure. signed informed consent forms, will be obtained from all patients prior to any study-related procedure, using an electronic consent procedure. given the timeliness of early treatment and the very low potential risk of the study intervention, the patient is expected to decide within 72 hours of a covid-19 diagnosis testing and no more than 4 days from the onset of covid-19 related symptoms. information on next of kin and permission to obtain medical records will be included in the consent form. s3. secondary analysis. secondary analyses will be tested at significance level of 0.05 without adjusting for multiple comparisons. secondary endpoints will be analyzed according to type of endpoints. the j o u r n a l p r e -p r o o f proportion of seroconversion and icu admission/ventilator support between treatment arms will be compared using logistic regression, as for the primary endpoint. generalized linear models will be fit to assess the treatment effect for continuous, dichotomous or count data; covariate (age, sex, race/ethnicity, obesity status, number of comorbidities, whether or not taking out-ofstudy vitamin d supplement ) adjustment will be done using the approach by tsiatis et al. [46] , which has been generalized to a setting of clustered data [47] and to accommodate missing data. [48] the methods gain efficiency without sacrificing type i error control by incorporating predictors of outcomes in the analysis in a principled way. cox proportional hazard models will be used for time to hospitalization or death for those who newly diagnosed with covid-19 at baseline. wilcoxon-mann whitney test will be used to compare self-reported disease severity between treatment arms. sensitivity analyses will be conducted to estimate the treatment effect among compliers. s4. data and safety monitoring. missing data will be identified in real-time; identification will trigger a second prompt for the participant to complete the survey. if data remain missing, the study staff will be notified to directly contact the participant. data integrity will be ensured by configuring on-line data capture to include plausible data ranges and branching logic checks and performing periodic statistical assessments for outliers. potential side effects of vitamin d are rare. they include gastrointestinal (gi) upset (presence or absence of symptoms of peptic ulcer, nausea, constipation, or diarrhea), and physician diagnosis of hypercalcemia or kidney stones. to minimize the risks of hypercalcemia and kidney stones, we will require that participants limit their total intake of calcium from all sources, including j o u r n a l p r e -p r o o f multivitamins, single supplements of calcium, and other drugs that contain calcium to 1200mg or less a day. on a weekly basis, reports of adverse events will be generated, and positive symptoms will be identified, with reports sent to the study staff for follow-up (e.g., participant or next of kin follow-up phone interview). all adverse events will be adjudicated using standard criteria for severity ratings and relatedness. we will establish an external dsmb. the members will include experts in infectious disease, biostatistics, clinical trials, and ethics (some with overlapping expertise). the dsmb will convene to review the final protocol and dsmb charter before study initiation and then periodically. the dsmb chair will receive all reports of unanticipated serious adverse events in real time. given the short duration of the study, an interim meeting is planned when half of the participants have been enrolled, or at 6 months, whichever occurs earlier. at the meeting they will assess whether study progress, data integrity and safety monitoring warrant continuation of the study and make recommendations accordingly. participants will be instructed to discontinue their study pills if, during follow-up, they receive a diagnosis of kidney stones, hypercalcemia, or other safety-exclusion conditions. participants will be advised to discontinue the study treatment if, in the course of follow-up, they report taking supplementary vitamin d (not from diet) that amounts to greater than 400 iu per day or daily calcium supplements that amount to greater than 1200 mg per day. covid-19 -navigating the uncharted clinical characteristics of 138 hospitalized patients with 2019 novel coronavirus-infected pneumonia in modulation of the immune response to respiratory viruses by vitamin d vitamin d attenuates rhinovirus-induced expression of intercellular adhesion molecule-1 (icam-1) and platelet-activating factor receptor (pafr) in respiratory epithelial cells vitamin d increases the antiviral activity of bronchial epithelial cells in vitro vitamin d decreases respiratory syncytial virus induction of nf-kappab-linked chemokines and cytokines in airway epithelium while maintaining the antiviral state respiratory epithelial cells convert inactive vitamin d to its active form: potential effects on host defense vitamin d-directed rheostatic regulation of monocyte antibacterial responses vitamin d and respiratory infection in adults toll-like receptor triggering of a vitamin d-mediated human antimicrobial response a review of micronutrients and the immune system-working in harmony to reduce the risk of infection cord blood vitamin d deficiency is associated with respiratory syncytial virus bronchiolitis vitamin d and respiratory infections vitamin d deficiency is associated with tuberculosis and latent tuberculosis infection in immigrants from sub-saharan africa low retinol-binding protein and vitamin d levels are associated with severe outcomes in children hospitalized with lower respiratory tract infection and respiratory syncytial virus or human metapneumovirus detection an association of serum vitamin d concentrations < 40 nmol/l with acute respiratory tract infection in young finnish men vitamin d status and acute lower respiratory j o u r n a l p r e -p r o o f infection in early childhood in sylhet vitamin d supplementation to prevent acute respiratory tract infections: systematic review and metaanalysis of individual participant data randomized trial of vitamin d supplementation and risk of acute respiratory infection in mongolia vitamin d3 supplementation in patients with frequent respiratory tract infections: a randomised and double-blind intervention study vitamin d3 and gargling for the prevention of upper respiratory tract infections: a randomized controlled trial effect of monthly high-dose vitamin d supplementation on acute respiratory infections in older adults: a randomized controlled trial effect of vitamin d3 supplementation on upper respiratory tract infections in healthy adults: the vidaris randomized controlled trial epidemiological and clinical characteristics of 99 cases of 2019 novel coronavirus pneumonia in wuhan, china: a descriptive study covid-19 infection: the perspectives on immune responses vitamin d status of hiv-infected women and its association with hiv disease progression, anemia, and mortality vitamin d and the immune system vitamin d and inflammation: potential implications for severity of covid-19 evidence that vitamin d supplementation could reduce risk of influenza and covid-19 infections and deaths the role of vitamin d in the prevention of coronavirus disease 2019 infection and mortality presenting characteristics, comorbidities, and outcomes among 5700 patients hospitalized with covid-19 in the vitamin d supplementation could possibly improve clinical outcomes of patients infected with coronavirus-2019 (covid-19) ssrn patterns of covid-19 mortality and vitamin d: an indonesian study longitudinal data analysis for discrete and continuous outcomes household secondary attack rate of covid-19 and associated determinants in guangzhou, china: a retrospective cohort study secondary attack rate of covid-19 in household contacts: systematic review identification of antiviral drug candidates against sars-cov-2 from fda-approved drugs designing clinical trials that accept new arms: an example in metastatic breast cancer effects of vitamin d supplementation on strength, physical performance, and falls in older persons: a systematic review the tolerability and biochemical effects of high-dose bolus vitamin d2 and d3 supplementation in patients with vitamin d insufficiency annual high-dose oral vitamin d and falls and fractures in older women: a randomized controlled trial effect of calcifediol treatment and best available therapy versus best available therapy on intensive care unit admission and mortality among patients hospitalized for covid-19: a pilot randomized clinical study over-the-counter and compounded vitamin d: is potency what we expect? eliminating vitamin d deficiency during the covid-19 pandemic: a call to action covariate adjustment for two-sample treatment comparisons in randomized clinical trials: a principled yet flexible approach augmented generalized estimating equations for improving efficiency and validity of estimation in cluster randomized trials by leveraging cluster-level and individual-level covariates accounting for 3. unable to complete online questionnaires or adhere to study requirements.j o u r n a l p r e -p r o o f key: cord-303917-2tu707ng authors: zhang, lei; liu, yunhui title: potential interventions for novel coronavirus in china: a systematic review date: 2020-03-03 journal: j med virol doi: 10.1002/jmv.25707 sha: doc_id: 303917 cord_uid: 2tu707ng an outbreak of a novel coronavirus (covid‐19 or 2019‐cov) infection has posed significant threats to international health and the economy. in the absence of treatment for this virus, there is an urgent need to find alternative methods to control the spread of disease. here, we have conducted an online search for all treatment options related to coronavirus infections as well as some rna‐virus infection and we have found that general treatments, coronavirus‐specific treatments, and antiviral treatments should be useful in fighting covid‐19. we suggest that the nutritional status of each infected patient should be evaluated before the administration of general treatments and the current children's rna‐virus vaccines including influenza vaccine should be immunized for uninfected people and health care workers. in addition, convalescent plasma should be given to covid‐19 patients if it is available. in conclusion, we suggest that all the potential interventions be implemented to control the emerging covid‐19 if the infection is uncontrollable. coronaviruses (covs) belong to the subfamily orthocoronavirinae in the family of coronaviridae in the order nidovirales, and this subfamily including α-coronavirus, β-coronavirus, γ-coronavirus, and deltacoronavirus. 1 coronaviruses primarily cause enzootic infections in birds and mammals and, in the last decades, have shown to be capable of infecting humans as well. 2 the outbreak of severe acute respiratory syndrome (sars) in 2002 and middle east respiratory syndrome (mers) in 2012 has demonstrated the lethality of coronaviruses when they cross the species barrier and infect humans. 2 belong to the β-coronavirus family. 3 recently, a novel flu-like coronavirus related to the mers and sars coronaviruses was found at the end of 2019 in china 4,5 and the evidence of human-to-human transmission was confirmed among close contacts. 6 the genome of covid-19 is a single-stranded positive-sense rna. 7 the sequence analysis showed that the covid-19 possessed a typical genome structure of coronavirus and belonged to the cluster of β-coronaviruses including sars-cov and mers-cov. 7 covid-19 was more than 82% identical to those of sars-cov. 8 vitamin a is the first fat-soluble vitamin to be recognized and β-carotene is its plant-derived precursor (table 1 ). there are three active forms of vitamin a in the body, retinol, retinal, and retinoic acid. vitamin a is also called "anti-infective" vitamin and many of the body's defenses against infection depend on an adequate supply. researchers have believed that an impaired immune response is due to the deficiency of a particular nutritional element. 10 vitamin a deficiency is strongly involved in measles and diarrhea 11 and measles can become severe in vitamin a-deficient children. in addition, semba et al 12 had reported that vitamin a supplementation reduced morbidity and mortality in different infectious diseases, such as measles, diarrheal disease, measles-related pneumonia, human immunodeficiency virus (hiv) infection, and malaria. vitamin a supplementation also offers some protection against the complications of other life-threatening infections, including malaria, lung diseases, and hiv. 13 jee et al 14 had reported that low vitamin a diets might compromise the effectiveness of inactivated bovine coronavirus vaccines and render calves more susceptible to infectious disease. the effect of infection with infectious bronchitis virus (ibv), a kind of coronaviruses, was more pronounced in chickens fed a diet marginally deficient in vitamin a than in those fed a diet adequate in vitamin a. 15 the mechanism by which vitamin a and retinoids inhibit measles replication is upregulating elements of the innate immune response in uninfected bystander cells, making them refractory to productive infection during subsequent rounds of viral replication. 16 therefore, vitamin a could be a promising option for the treatment of this novel coronavirus and the prevention of lung infection. b vitamins are water-soluble vitamins and work as part of coenzymes. each b vitamin has its special functions. for example, vitamin b2 (riboflavin) plays a role in the energy metabolism of all cells. vitamin b2 deficiency had been suspected to occur among us elderly. 17 keil et al 18 had reported that vitamin b2 and uv light effectively reduced the titer of mers-cov in human plasma products. vitamin b3, also called nicotinamide, could enhance the killing of staphylococcus aureus through a myeloid-specific transcription factor and vitamin b3 was efficacious in both prophylactic and therapeutic settings. 19 moreover, vitamin b3 treatment significantly inhibited neutrophil infiltration into the lungs with a strong anti-inflammatory effect during ventilatorinduced lung injury. however, it also paradoxically led to the development of significant hypoxemia. 20 vitamin b6 is also needed in protein metabolism and it participates in over 100 reactions in body tissues. in addition, it also plays important role in body immune function as well. as shortage of b vitamins may weaken host immune response, they should be supplemented to the virus-infected patients to enhance their immune system. therefore, b vitamins could be chosen as a basic option for the treatment of covid-19. vitamin c is another water-soluble vitamin and it is also called ascorbic acid, which means "no-scurvy acid." vitamin c is best known for its role in the synthesis of collagen in connective tissues and acts as an antioxidant. vitamin c also supports immune functions and protects against infection caused by a coronavirus. 21 infection. vitamin c may also function as a weak antihistamine agent to provide relief from flu-like symptoms such as sneezing, a running or stuffy nose, and swollen sinuses. 23 three human controlled trials had reported that there was significantly lower incidence of pneumonia in vitamin c-supplemented groups, suggesting that vitamin c might prevent the susceptibility to lower respiratory tract infections under certain conditions. 24 the covid-19 had been reported to cause lower respiratory tract infection, so vitamin c could be one of the effective choices for the treatment of covid-19. vitamin d is not only a nutrient but also a hormone, which can be synthesized in our body with the help of sunlight. in addition to its role in maintaining bone integrity, it also stimulates the maturation of and omega-6 pufas predominantly promote anti-inflammatory and pro-inflammatory effects. they are precursors of resolvins/protectins and prostaglandins/leukotrienes, respectively. 31 begin et al 32 had studied plasma lipids levels in patients with aids and had found that a selective and specific lack of the long-chain pufas of omega-3 series, which are found in high concentrations in fish oils. in addition, protectin d1, the omega-3 pufa-derived lipid mediator, could markedly attenuate influenza virus replication via rna export machinery. in addition, treatment of protectin d1 with peramivir could completely rescue mice from flu mortality. 33 leu et al 34 had found that several pufas also had anti-hepatitis c virus (hcv) activities. therefore, omega-3 including protectin d1, which served as a novel antiviral drug, could be considered for one of the potential interventions of this novel virus, covid-19. selenium is an essential trace element for mammalian redox biology. 35 the nutritional status of the host plays a very important role in the defense against infectious diseases. 36 nutritional deficiency impacts not only the immune response but also the viral pathogen itself. 10 dietary selenium deficiency that causes oxidative stress in the host can alter a viral genome so that a normally benign or mildly pathogenic virus can become highly virulent in the deficient host under oxidative stress. 10 deficiency in selenium also induces not only impairment of host immune system, but also rapid mutation of benign variants of rna viruses to virulence. 37 beck et al 38 had reported that selenium deficiency could not only increase the pathology of an influenza virus infection but also drive changes in genome of coxsackievirus, permitting an avirulent virus to acquire virulence due to genetic mutation. 39 it is because that selenium could assist a group of enzymes that, in concert with vitamin e, work to prevent the formation of free radicals and prevent oxidative damage to cells and tissues. 37 it was reported that synergistic effect of selenium with ginseng stem-leaf saponins could induce immune response to a live bivalent infectious bronchitis coronavirus vaccine in chickens. 40 therefore, selenium supplementation could be an effective choice for the treatment of this novel virus of covid-19. zinc is a dietary trace mineral and is important for the maintenance and development of immune cells of both the innate and adaptive immune system. 41 zinc deficiency results in dysfunction of both humoral and cell-mediated immunity and increases susceptibility to infectious diseases. 42 zinc supplement given to zinc-deficient children could reduce measles-related morbidity and mortality caused by lower respiratory tract infections. 43 increasing the concentration of intracellular zinc with zinc-ionophores like pyrithione can efficiently impair the replication of a variety of rna viruses. 44 in addition, the combination of zinc and pyrithione at low concentrations inhibits the replication of sars coronavirus (sars-cov). 44 56 in addition, interferons have also been found to be potent inhibitors of mers-cov replication. 57 moreover, the combination of interferon-α-2a with ribavirin was administered to patients with severe mers-cov infection and the survival of these patients was improved. 57 these findings suggest that these approved ifn's could be also used for the treatment of this novel coronavirus. intravenous gammaglobulin (ivig) was first developed in the late 1970s 58 and is probably the safest immunomodulating drug available for long-term use in all ages. however, it does have adverse reactions. during the sars outbreak in 2003, ivig was used extensively in singapore. however, one-third of critically ill patients developed venous thromboembolism including pulmonary embolism despite the use of lowmolecular weight heparin prophylactic. 59 it was due to the ivig-induced increase of viscosity in hypercoagulable states of sars patients. 60 thymosin α-1 (ta1) is a thymic peptide hormone and it has a peculiar ability to restore the homeostasis of the immune system. 61 it is was first isolated from thymic tissue in the mid-sixties and it had gained much attention for its immunostimulatory activity. 62 it was chemically synthesized and used in diseases where the immune system was hindered or impaired. 63 besides its role in thymocyte development, thymosin α-1 could also increase resistance to glucocorticoid-induced death of the thymocyte. 64 thymosin α-1 could also be used as immune enhancer to sars patients and it was effective in controlling the spread of the disease. 65, 66 methylprednisolone was often used during the current treatment of covid-19 and the side effect of corticoid-induced death of thymocytes should be considered. so, it is wise to use thymosin α1 before the administration of methylprednisolone. thymopentin (tp5, munox), a synthetic pentapeptide corresponding to the active site of thymopoietin, had been shown to restore antibody production in old mice. 67 additionally, it could enhance the antibody response in humans when it was applied subcutaneously three times a week at doses of 50 mg. 68 moreover, thymopentin could also be used as an adjuvant treatment for non-responders or hyporesponders to hepatitis b vaccination. 69 levamisole, a synthetic low-molecular-weight compound, is the first member of a new class of drugs that can increase the functions of cellular immunity in normal, healthy laboratory animals. 70 medicine could also be considered as a choice to enhance host immunity against the infection of covid-19. in summary, the general treatment for viral infection including nutritional interventions and all kinds of immunoenhancers has been used to enhance host immunity against rna viral infections. therefore, they may also be used to fight covid-19 infection by correcting the lymphopenia of patients. chymotrypsin-like (3c-like) and papain-like protease (plp) are coronavirus encoded proteins (table 2) . they have an essential function for coronaviral replication and also have additional function for inhibition of host innate immune responses. targeting 3c-like protease (3 clpro) and papain-like protease (plpro) are more attractive for the treatment of coronavirus. 77 cinanserin cinanserin, an old drug, is well-known for serotonin receptor antagonist. it could inhibit the 3 chymotrypsin-like (3c-like) protease and was a promising inhibitor of replication of sars-cov. 78 the 3clpro was also been found to be encoded in covid19. 7 therefore, cinanserin may be a better choice for the treatment of covid-19 infection. papain-like protease (plp) of human coronavirus is a novel viralencoded deubiquitinase and is an ifn antagonist for inhibition of host innate antiviral immune response. diarylheptanoids is a natural product and is extracted from the stem bark of alnus japonica. it had been found to be able to inhibit papainlike protease of sars-cov. 77 therefore, cinanserin together with flavonoids and other natural compounds could be chosen as alternative choices to fight covid-19 infection through targeting coronaviral proteases. angiotensin-converting enzyme-2 (ace2) is a type i integral membrane protein which functions as a carboxypeptidase and is the first human homolog of ace. 84 ace2 efficiently hydrolyzes the potent vasoconstrictor angiotensin ii to angiotensin (1-7) and it has been implicated in hypertension, cardiac function, heart function, and diabetes. 84 in addition, ace2 is also a functional receptor of sars-cov and it mediates virus entry into the cell through binding with spike (s) protein. 85 chloroquine is a 9-aminoquinoline known since 1934. apart from its well-known antimalarial effects, the drug also has many interesting biochemical properties including antiviral effect. in addition, it had been used against viral infection. 90 moreover, chloroquine was also found to be a potent inhibitor of sars coronavirus infection through interfering with ace2, one of cell surface binding sites for s protein of sars-cov. 91 emodin is an anthraquinone compound derived from genus rheum and polygonum and it is also a virucidal agent. 92 emodin could significantly block the interaction between the s protein of sars-cov and ace2. therefore, emodin might abolish sars-cov infection by competing for the binding site of s protein with ace2. 93 promazine, anti-psychotic drug, shares a similar structure with emodin. it has been found to exhibit a significant effect in inhibiting the replication of sars-cov. 94 as compared to emodin, promazine exhibited potent inhibition of the binding of s protein to ace2. these findings suggested that emodin and promazine might be able to inhibit sars-cov infectivity through blocking the interaction of s protein and ace2. 93 therefore, the monoclonal antibody (scfv80r), chloroquine, emodin, and promazine could be used as alternative choices for the treatment of covid-19. nicotianamine is an important metal ligand in plants 95 and it is found a novel angiotensin-converting enzyme-2 inhibitor in soybean. 96 so, it is another potential option to be used to reduce the infection of covid-19. ribavirin, a broad-spectrum antiviral agent, is routinely used to treat hepatitis c (table 3 ). during the outbreak of sars, ribavirin was used extensively for most cases with or without concomitant use of steroids in hong kong. 97 however, there was considerable skepticism from overseas and local experts on the efficacy of ribavirin. 98 because there was a report mentioned that ribavirin had no significant activity against sars-cov in vitro 52 and the use of ribavirin was found to be associated with significant toxicity, including hemolysis (in 76%) and decrease in hemoglobin (in 49%). 99 remdesivir (rdv), a nucleoside analog gs-5734, had been reported to inhibit human and zoonotic coronavirus in vitro and to restrain severe acute respiratory syndrome coronavirus (sars-cov) in vivo. 104 recently, the antiviral activity of rdv and ifn-β was found to be superior to that of lpv/rtv-ifn-β against mers-cov in vitro and in vivo. 101 in addition, rdv could improve pulmonary function and reduce lung viral loads and severe lung pathology in mice, which was impossible for lpv/rtv-ifn-β. 101 recently, a first covid-19 nelfinavir is a selective inhibitor of hiv protease, which is responsible for posttranslational processing of hiv propeptides. 106 yamamoto et al 107 had found that nelfinavir could strongly inhibit the replication of sars-cov. therefore, nelfinavir could also be an option for the treatment of covid-19. arbidol (arb) is a russian-made small indole-derivative molecule and is licensed in russia and china for prophylaxis and treatment of influenza and other respiratory viral infections. 108 arbidol had been found to be able to block viral fusion against influenza a and b viruses as well as hepatitis c virus. 109 arbidol could also inhibit hepatitis c virus by blocking hepatitis c virus entry and replication in vitro. 110 in addition, arbidol and its derivatives, arbidol mesylate, had been reported to have antiviral activity against the pathogen of sars in the cell cultures and arbidol mesylate was nearly 5 times as effective as arbidol in reducing the reproduction of sars virus in the cultured cells. 111 nitric oxide (no) is a gas with diverse biological activities and is produced from arginine by no synthases. no is able to interact with superoxide, forming peroxynitrite, which, in turn, can mediate bactericidal or cytotoxic reactions. 112 in addition, no had played an important role in regulating airway function and in treating inflammatory airway diseases. 113 rossaint et al 114 reported that the beneficial effects of no inhalation could be observed in most patients with severe acute respiratory distress syndrome. no was also found to inhibit the synthesis of viral protein and rna. 115 (table 3 ). 117 ala, as an antioxidant, has played a pivotal role in scavenging free radicals to protect against oxidative damage in several diseases. 118 in addition, ala also had its capability to enhance intracellular glutathione (gsh) levels 118 and to normalize the oxidative stress induced by dexamethasone in chicken. 119 wu et al 120 also reported that the oxidative stress in host cells was an important factor in the infectivity of human coronavirus 229e and the glucose-6-phosphate dehydrogenase (g6pd) deficiency was another factor that enhanced human coronavirus 229e infection. the addition of α-lipoic acid to g6pd-knockdown cells could attenuate the increased susceptibility to human coronavirus 229e infection. 120 interestingly, baur et al 121 also found that α-lipoic acid was effective to inhibit the replication of hiv-1. in summary, we speculate that ala could be also used as an optional therapy for this new virus. females, generally, mount more robust immune responses to viral challenges than males, which can result in more efficient virus clearance. 122 epidemiological studies showed that males experiencing a higher rate of incidence and case fatality compared with females after sars-cov infection. 123, 124 during the mers outbreak, the disease occurrence rate in men was almost twice as much as in women and the case fatality rate was the same as the occurrence rate among men and women. 125 in addition, channappanavar et al had reported that male mice were more susceptible to sars-cov infection compared with age-matched female mice. however, the mortality was increased in female mice when the ovariectomy was done or the estrogen receptor antagonist was given. 126 wei et al 127 also found that serum levels of prolactin, follicle-stimulating hormone, and luteinizing hormone of zhang and liu | 485 sars patients were significantly higher than those of control groups, while estradiol (e2), pregnancy hormone, and thyroid-stimulating hormone were considerably lower than those of normal controls. interestingly, estrogenic compounds had been found to reduce influenza a virus replication in primary human nasal epithelial cells derived from female, but not male, donors. 128 in addition, resveratrol, a phytoestrogen from grape seeds and red wine, had been reported to be a potent anti-mers agent in vitro. 129 therefore, 17β-estradiol or phytoestrogen could also be an alternative option to be considered for the treatment of covid-19. mucroporin-m1 is a scorpion venom-derived peptide and has broadspectrum virucidal activity against many viruses including measles, influenza h5n1 viruses, and sars-cov. 130 therefore, this peptide could also be used for the treatment of covid-19 infection as well as the new drug design to target covid-19. in this review, we summarize all the potential interventions for regarding short-term protection and prevention of viral infection, passive immunotherapy should not be neglected. 135 monoclonal antibody therapy is one of the best forms of passive immunotherapy. a human igg1 mab, cr3014, had been generated and it had been found to be reactive with whole inactivated sars coronavirus. in addition, cr3014 could be used as prophylaxis for sars coronavirus infection in ferrets. 136 however, cr3014 was found to be able to block the interaction in parent sars-cov strain, but not in escape variants. this led to the ineffectiveness of cr3014 to prevent infection in humans. cr3022 was another monoclonal antibody and it had been found to neutralize cr3014 escape viruses. 136 the combination of cr3014 and cr3022 had also been reported to have the potential to control immune escape. 135 however, the clinical trial of cr3022 with cr3014 had never been tried due to the high cost of manufacturing. convalescent plasma can also be called passive immunotherapy. it is usually chosen when there are no specific vaccines or drugs available for emerging infection-related diseases. 137 arabi et al had tested the feasibility of convalescent plasma therapy as well as its safety and clinical efficacy in critically ill mers patients. they found that convalescent plasma had an immunotherapeutic potential for the treatment of mers-cov infection. 138 in addition, convalescent plasma from recovered sars patients had also been reported to be useful clinically for treating other sars patients. 139, 140 importantly, the use of convalescent plasma or serum was also suggested by the world health organization under blood regulators network when vaccines and antiviral drugs were unavailable for an emerging virus. in summary, these findings suggest that the current children's rna-virus-related vaccines are the best alternative methods to be used to vaccinate the uninfected people and health care workers. convalescent plasma should be routinely used for the treatment of covid-19 infected critically sick patients if it is available. the avian ibv vaccine is also another choice for clinical trials if its safety has been approved in monkeys. therefore, we suggest that all the potential interventions be implemented to control the emerging covid-19 if the infection is uncontrollable. the authors declare that there are no conflict of interests. yunhui liu http://orcid.org/0000-0002-9920-9933 bats and coronaviruses coronavirus envelope protein: current knowledge middle east respiratory syndrome new sars-like virus in 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feasibility, safety, clinical, and laboratory effects of convalescent plasma therapy for patients with middle east respiratory syndrome coronavirus infection: a study protocol use of convalescent plasma therapy in sars patients in hong kong retrospective comparison of convalescent plasma with continuing high-dose methylprednisolone treatment in sars patients key: cord-330834-zqm4egei authors: drall, kelsea m.; field, catherine j.; haqq, andrea m.; de souza, russell j.; tun, hein m.; morales-lizcano, nadia p.; konya, theodore b.; guttman, david s.; azad, meghan b.; becker, allan b.; lefebvre, diana l.; mandhane, piush j.; moraes, theo j.; sears, malcolm r.; turvey, stuart e.; subbarao, padmaja; scott, james a.; kozyrskyj, anita l title: vitamin d supplementation in pregnancy and early infancy in relation to gut microbiota composition and c. difficile colonization: implications for viral respiratory infections date: 2020-08-11 journal: gut microbes doi: 10.1080/19490976.2020.1799734 sha: doc_id: 330834 cord_uid: zqm4egei in canada and the us, the infant diet is supplemented with vitamin d via supplement drops or formula. pregnant and nursing mothers often take vitamin d supplements. since little is known about the impact of this supplementation on infant gut microbiota, we undertook a study to determine the association between maternal and infant vitamin d supplementation, infant gut microbiota composition and clostridioides difficile colonization in 1,157 mother-infant pairs of the child (canadian healthy infant longitudinal development) cohort study over 2009–2012. logistic and maaslin regression were employed to assess associations between vitamin d supplementation, and c. difficile colonization, or other gut microbiota, respectively. sixty-five percent of infants received a vitamin d supplement. among all infants, infant vitamin d supplementation was associated with a lower abundance of genus megamonas (q = 0.01) in gut microbiota. among those exclusively breastfed, maternal prenatal supplementation was associated with lower abundance of bilophila (q = 0.01) and of lachnospiraceae (q = 0.02) but higher abundance of haemophilus (q = 0.02). there were no differences in microbiota composition with vitamin d supplementation among partially and not breastfed infants. neither infant nor maternal vitamin d supplementation were associated with c. difficile colonization, after adjusting for breastfeeding status and other factors. however, maternal consumption of vitamin-d fortified milk reduced the likelihood of c. difficile colonization in infants (adjustedor: 0.40, 95% ci: 0.19–0.82). the impact of this compositional difference on later childhood health, especially defense against viral respiratory infection, may go beyond the expected effects of vitamin d supplements and remains to be ascertained. most infants in north america are supplemented with vitamin d subsequent to recommendations that all breastfed infants receive 400 iu/day, an amount that is also present in commercial infant formulas. 1,2 however, infant vitamin d supplementation during breastfeeding is not common practice in australia and several european countries, including italy and spain, 3, 4 and compliance rates in canada and the us are moderate. 5, 6 vitamin d has shown protective activity against the development of preschool wheeze when provided as a maternal prenatal supplement. 7 supplementation of preterm infants with vitamin d has reduced recurrent wheeze in a randomizedcontrolled trial. 8 independent of gestational age and breastfeeding status, infant supplementation before 6-months has shown future benefit in raising serum vitamin d levels and reducing hospital length-of-stay of infants hospitalized for bronchiolitis, a respiratory infection often caused by respiratory syncytial virus contact : anita l kozyrskyj kozyrsky@ualberta.ca 3-527 edmonton clinic health academy, edmonton, ab t6g 1c9, canada supplemental data for this article can be accessed here. (rsv). 9 of note, low vitamin d levels has been associated with susceptibility to other viral respiratory infections, including sars-cov-2 (covid-19 disease). 10 furthermore, the high rates of food allergy and recurrent wheeze in australian children have been attributed to vitamin d insufficiency during infancy. 11 while the immunological roles (both innate and adaptive) of vitamin d have been extensively studied, vitamin d has many physiological roles important for the maintenance of gut microbiota and exclusion of opportunistic microbes. vitamin d receptors (vdrs) are found on immune cells including t cells, b cells and dendritic cells, but are also highly expressed in intestinal enterocytes where they act as transcription factors for the secretion of antimicrobial peptides and tight junction proteins that maintain intestinal epithelial barrier function. 12, 13 asystematic review of in vivo research has summarized the impact of vitamin d on mammalian gut microbiota 14 but only included evidence from two studies in human infants. meanwhile, anewer human study identified prenatal vitamin d supplementation as an important predictor of variance in gut microbial profiles of infants. 15 in the koala birth cohort, clostridioides difficile counts in 1-month old infants were reduced following maternal prenatal supplementation with multivitamins containing vitamin d. 16 although asymptomatic c. difficile colonization occurs in approximately 30% of young infants, it is less common in breastfed infants and it has been associated with a disrupted gut microbiota composition and later childhood allergic disease. in adults, vitamin d deficiency has also been correlated with c. difficile infection, while community incidence of c. difficile has been associated with rsv and influenza virus circulation. 17 notwithstanding that infant feeding type shapes the infant gut microbiome, 18, 19 attention is shifting to specific micronutrients. if vitamin d influences the gut microbiome, supplementation during breastfeeding may confer additional benefits. 2, 20 the primary objective of this study was to determine the association between maternal perinatal and infant vitamin d supplementation, and infant gut microbiota composition at 3 months of age, including c. difficile colonization. at an average age of 3.52 months (sd: 0.97 months), 64.7% of our 1,157 infants received a vitamin d 3 supplement (referred to as vitamin d throughout) in the form of vitamin d drops (table 1) . a high proportion (74.8%) of exclusively breastfed infants received vitamin d supplements. supplementation was less frequent in partially (67.8%) and exclusively formula fed infants (25.6%) ( table 1 ). the manitoba site had the lowest prevalence of infant vitamin d supplementation (43.4% overall, 53.4% in exclusively breastfed infants). fifteen percent of infants were born to mothers who did not report taking vitamin d supplements or took <400iu/day during pregnancy and lactation, compared to 67% whose mothers reported taking vitamin d supplements (≥400 iu/day) both pre and postnatally. overall, 29.7% of infants were colonized with c. difficile, but less among exclusively breastfed infants (22.1%, table 1 ). among those infants who were colonized with c. difficile, mothers were usually younger, had a higher bmi, and were less frequently of asian ethnicity (table 1) . asmaller proportion of infants colonized with c. difficile were born to mothers who consumed at least 3 cups of fortified milk a day, were more frequently living in homes with furry pets, born in edmonton and less likely to receive vitamin d drops. in all infants, direct vitamin d supplementation (or: 0.76, 95% ci: 0.59-0.99, p = .04), as well as postnatal supplementation (≥ 2 sources of vitamin d, (or: 0.67, 95% ci: 0.45-0.98, p = .04), were associated with lower odds of c. difficile colonization compared to the absence of supplementation; however, these associations were lost upon adjustment for covariates, notably infant feeding mode. prenatal maternal vitamin d supplementation was not associated with within exclusively breastfed infants, the crude odds ratios for c. difficile colonization were not statistically significant with infant vitamin d supplementation (or: 0.87, 95% ci: 0.57-1.32, p = .585) nor with maternal supplementation (table s1 ). these null associations were unchanged following adjustment for birth mode, maternal milk consumption, household pets, study center and infant age at sample collection ( figure 1a , table s1 ). no significant interaction terms were discovered between variables. asensitivity analysis was conducted to ensure that results were not affected by site variations in infant supplementation. no deviations from the main findings were noted for associations between vitamin d supplementation and infant c. difficile colonization after the manitoba site was excluded (data not shown). independent of infant or maternal prenatal vitamin d supplementation, prenatal maternal milk consumption greater than or equal to 3 cups per day, compared to 1 or less cups per day, was significantly associated with lower odds (aor: 0.40, 95% ci: 0.19-0.82, p = .01, table s2 ) of c. difficile colonization in exclusively breastfed infants. in this final adjusted model, c. difficile colonization was twice more likely in infants born via elective cesarean and in the presence of household pets (table s2) . no associations between vitamin d supplementation and c. difficile colonization were observed (summary table 2 ) within partially (figure 1b) or exclusively formula fed infants ( figure s1 ). following adjustment for birth mode and feeding mode, microbiota of the genus megamonas (veillonellaceae family) were of significantly lower abundance in all infants supplemented with vitamin d (q = 0.01, table 3 ). furthermore, peptostreptococcus (peptostreptococcaceae family) were lower in supplemented infants and eubacterium (eubacteriaceae family) were depleted in infants whose mothers took a pre and postnatal vitamin d supplement (>400iu/day); however statistical significance for these two genera was lost upon fdr correction (table 3) . exclusively breastfed infants born to mothers who were taking ≥400iu/day both pre and postnatally exhibited a lower relative abundance of proteobacteria, specifically those of the genus bilophila (q = 0.01, table 3 ). furthermore, bacteria belonging to the lachnospiraceae family (q = 0.02) were depleted and microbes belonging to the pasteurellaceae family (haemophilus spp., q = 0.02) were enriched compared to infants nursed by mothers taking <400iu/day ( table 3 ). the same modeling procedure was followed for partially and exclusively formula fed infants but none of the associations survived fdr correction (summary table 2 ). with the aim to address a gap in emerging discussions on vitamin d and intestinal homeostasis in infants, 14 we undertook this gut microbiome study in a general population of 1,157 canadian mothers and infants. three-quarters of breastfed infants were supplemented with vitamin d drops and 85% of mothers took vitamin supplements containing ≥400 iu of vitamin d daily during pregnancy and postnatally. at 3-4 months of age, c. difficile colonization of the infant gut was less prevalent with infant vitamin d supplementation but this was explained by the extent of breastfeeding, a strong deterrent of c. difficile. 21 within exclusively breastfed infants, neither infant nor maternal vitamin d supplementation were related to c. difficile colonization status. whereas c. difficile counts were reportedly lower in colonized, breastfed infants of mothers with prenatal vitamin d intake ≥400 iu/day in the koala study, infant c. difficile colonization rates in this cohort did not differ by infant vitamin d supplement intake. 16 our findings agree with those of the koala study regarding direct vitamin d supplementation of breastfed infants, for which there were no associations with c. difficile colonization of their gut microbiota. 16 however, we found direct vitamin d supplementation of infants to be associated with a lower abundance of megamonas in gut microbiota. this association was found in all study infants and was independent of feeding mode. while little is known about megamonas in infancy, this genus was enriched in the gut microbiota of male infants born to mothers with prenatal asthma in a previous publication from the child cohort. 22 in addition to childhood asthma, maternal history of asthma is a risk factor for greater severity of viral bronchiolitis in offspring. 23 megamonas has recently been reported to be more abundant in the gut microbiota of adult males with higher testosterone levels 24 and the role of this sex steroid is currently being scrutinized in asthma pathogenesis. 25 in view of reported benefits of the vitamin d supplementation of high risk mothers and of infant populations where supplementation is not the norm, 7,11 the megamonas genus of veillonellaceae may be a possible link between vitamin d and asthma or viral respiratory infection that merits further examination. it would also further support recommendations for the supplementation of formula-fed infants. vitamin d plays a crucial role in both innate immunity, via toll-like figure 3 ). adjusted for maternal milk consumption during pregnancy, household pets, age at stool sample collection, study center and other supplement categories; d-drop use adjusted for maternal d supplementation (pre/post); post-natal supplements adjusted for pre-natal supplement use; and pre-natal supplement use adjusted for post-natal supplement use (maternal and infant). adjusted odds ratios (aor) and 95% confidence intervals (error bars) calculated using logistic regression in stata (version 13.0). receptor signaling of macrophages in response to pathogens, and adaptive immunity, by inhibiting proliferation of t cells and secretion of inflammatory cytokines. 13, 26 further, there is emerging evidence for its role in the lung microbiome and gutlung axis. 27 we also found associations with maternal pre and postnatal vitamin d supplementation (≥400iu/day) in exclusively breastfed infants, namely a lower relative abundance of bilophila spp. bilophila have been linked to inflammation and colitis in mice, 28, 29 and colic in infants. 30 genus bilophilia produce secondary bile acids, ligands for vdrs, and levels of these microbiota are elevated in the presence of taurine or bile. [31] [32] [33] vitamin d receptors are highly expressed in the proximal colon and involved in the production of defensins, cathelicidins, claudins and zonulin occludens, important to gut barrier integrity. 12, 34, 35 newborns conjugate bile acids with taurine but have the capacity to utilize glycine, especially when fed formula. [31] [32] [33] 36 this may explain why bilophila species were uniquely altered among exclusively breastfed infants. maternal supplementation with vitamin d was also associated with depletion of lachnospiraceae but enhancement of haemophilus spp, both of which are reported to be altered in mammalian studies of vitamin d. 14 the reduction in abundance of bilophila and other changes to infant gut microbiota following maternal vitamin d supplementation points to pathways involving production of secondary bile acids. interestingly, maternal prenatal consumption of 3 or more cups of fortified milk per day reduced the likelihood of c. difficile colonization in exclusively breastfed infants by 60%, even after adjustment for infant vitamin d supplementation, maternal vitamin d supplementation and other covariates (aor: 0.40, table 3 . gut microbiota composition in all study infants. multivariate linear regression (maaslin) predicting arcsine square root transformed relative abundances of microbiota in all study infants (n = 1,157) , exclusively breastfed infants (n = 647), partially breastfed (n = 314) and exclusively formula fed (n = 195) according to postnatal maternal and infant vitamin d supplementation practices. table s2 ). transitioning to cow's milk after exclusive breastfeeding seems to have an inhibitory influence on c. difficile colonization in infants, 37 whereas c. difficile infection is more common in children with cow's milk intolerance. 38 furthermore, greater maternal dietary intake of vitamin d during pregnancy has been reported to reduce risk of cow's milk allergy in offspring. 39 our findings suggest a putative role of vitamin d fortified-milk consumption during pregnancy but maternal milk consumption may be equally correlated with other maternal dietary patterns [40] [41] [42] or lifestyle factors (i.e. cleaning product use 43 ) that influence the composition of infant gut microbiota. an important limitation of this work is that we could not distinguish between those with darker skin pigmentation and other ethnicities, beyond caucasian and asian. these populations have been shown to produce less subcutaneous vitamin d, making them at greater risk of low vitamin d. 44 we also observed study site differences specifically that the prevalence of manitoban infant supplementation was lower, in just over 50% of exclusively breastfed infants. according to the sensitivity analysis we conducted, study findings were unchanged if the manitoba site was excluded. finally, we did not have access to maternal or infant serum vitamin d levels. however, for microbiome research, intestinal levels are likely more important than serum levels and reference values for intestinal vitamin d concentrations have yet to be determined. instead, this study relied on selfreport questionnaires for reporting of vitamin d supplementation. questionnaire response categories did not allow us to explore potential differences within the group of mothers taking more than 400iu/day. future studies would benefit from a more specific nutrition/supplement question, such as the one administered in the alberta pregnancy outcomes and nutrition (apron) study, which was pilot-tested to ensure efficient and detailed collection of vitamin intake and dosing in the canadian context. 45 however, this limitation is not likely to have a large effect on our findings as the apron study found that the average vitamin d intake during pregnancy from supplements and diet combined was 600 iu/day. 46 ultimately, this study found evidence of an association between maternal vitamin d supplementation with the gut microbiota composition of all study infants, notably a lower abundance of megamonas, with its potential implications for host defense against viral respiratory infections. in exclusively breastfed infants, we found evidence of an association between direct vitamin d supplementation and lower abundance of bilophila and members of the lachnospiraceae, and a higher abundance of haemophilus at 3-months of age. yet, vitamin d supplementation did not appear to be associated with c. difficile colonization in any of the feeding groups. it is essential to confirm our findings to fully comprehend the relationship between vitamin d and the gut microbiota of infants, and to understand how current standards of care around vitamin d supplementation support healthy development. this observational study included 1,157 families participating in the child cohort study. 47 mothers were recruited during their second trimester of pregnancy between january 2009 and december 2012 from the vancouver, edmonton or manitoba sites (inclusion and exclusion criteria outlined at www. childstudy.ca). all study infants provided a fecal sample and data on breastfeeding status and infant vitamin d supplement intake ( figure s2 ). mothers provided informed consent upon enrollment and the human research ethics boards at the university of manitoba, university of alberta, and university of british columbia approved this study. fecal samples were collected at 3-4 months of age using a standardized protocol during a planned home visit. methods of sample collection, dna extraction and amplification, 16s ribosomal rna sequencing, and microbial taxonomic classification are described elsewhere. 18 briefly, collected samples were aliquoted stored at −80°c until analyzed. dna extraction was performed using 80-200 mg of frozen sample using the qiaamp dna stool mini kit (qiagen inc, valencia ca). bacterial 16s rrna genes were amplified at the hypervariable v4 region and sequenced using the illumina miseq platform (san diego, ca). sequences were clustered with usearch (version 6.1) 48 at >97% similarity against the greengenes reference database (version 13.8) for taxonomic classification in qiime 1.8 and excluded if <60% similarity. taxon relative abundance was the outcome variable for the microbiota composition analysis. a specific 16s primer was used for targeted amplification and quantification of c. difficile, as described elsewhere. 21 multiplex assays were prepared using the quantinova multiplex pcr kit (qiagen) with appropriate primers and probes. each qpcr reaction cycle consisted of an initial denaturation for 2 min at 95.0•c, 40 cycles of denaturation for 5 s at 95•c and annealing/extension/reading for 20 s at 60•c and was performed on the miniopticontm real-time pcr system (bio-rad, hercules, ca, usa). the outcome variable for c. difficile presence was fecal colonization status, yes/no. maternal vitamin d supplementation from various sources (prenatal vitamins, multivitamins or vitamin d supplements, including dose and frequency of intake) was collected in questionnaires during pregnancy ( figure s3 ) and 3-months postpartum ( figure s4 ). mothers were asked about infant supplementation with vitamin d 3 drops (referred to as vitamin d throughout) during the first three months ( figure s4 ). maternal and infant supplementation variables were created following this algorithm: i. maternal prenatal vitamin d intake: a 3-category exposure variable was created from the relevant questionnaire information: 1) one supplement or no supplements containing vitamin d, 2) two supplements containing vitamin d and 3) three or more supplements containing vitamin d. ii. postnatal vitamin d intake: a 4-category exposure variable was created from the relevant questionnaire information: 1) low (i.e. one maternal source, no infant direct) or no vitamin d from supplements, 2) two maternal supplements with vitamin d or infant direct vitamin d, 3) infant direct and one maternal supplement, and 4) two or more maternal supplements and infant direct vitamin d. iii. maternal perinatal intake based on the dosing information. based on current dietary reference intakes for vitamin d supplementation of 400 iu/day, and a recommended dietary allowance of 600 iu/day during pregnancy and breastfeeding, 44,49 a final 4 category variable was created: 1) no maternal vitamin d or less than 400 iu/day, 2) prenatal only maternal vitamin d supplementation ≥400 iu/day, 3) postnatal only maternal vitamin d supplementation ≥400 iu/day and 4) prenatal and postnatal supplementation ≥400 iu/day. furthermore, mothers reported their milk intake in a food frequency questionnaire administered during pregnancy as milk/fortified substitute beverage consumption (1 cup), milk/fortified substitute use on cereal (1/2 cup) and milk/fortified substitute in tea/coffee (1 tbsp). to measure dietary sources of vitamin d through fortified milk and/or plant-based alternatives, a 3-category variable was created: 1) 1 or fewer cups/day, 2) 2 cups/ day, 3) 3 or more cups/day. data from study questionnaires or medical charts were obtained and used to create the following covariates: season of birth (low uvb season, october -march); high uvb season, april -september), 50 maternal pre-pregnancy age and body-mass-index (bmi), infant age at stool collection, hospital length of stay at birth, mode of delivery, infant sex, feeding mode at stool collection (exclusively breastfed [no non-human milk, juices, formula or solids], partially breastfed or exclusively formula fed), antibiotics use, household income, ethnicity, maternal depressive symptoms, pets in the home and study center. all descriptive (fisher's exact tests, t-tests, anova) and regression tests were completed using stata (version 13.0) statistical software and the online galaxy platform (version 1.0.1). logistic regression models were used to determine the association between vitamin d supplement use and c. difficile colonization and were built using purposeful selection of covariates. 51 models 52 were run in all infants, then stratified by feeding mode due to the strong association between breastfeeding and infant vitamin d supplementation. one infant did not have data on feeding mode (stratified analyses, n = 1,156). microbial taxon abundance was compared using multivariate association with linear models (maaslin), which was adjusted for covariates and subjected to false discovery rate (fdr) correction with q ≤ 0.05. the data and analysis code that support the findings of this study can be made available from the corresponding author and child cohort study coordinators upon reasonable request. these data, including study participant data, are securely stored in the https://childdb.ca database. supplementation: recommendations for canadian mothers and infants centers for disease control and prevention. vitamin d [internet variations in infant and childhood vitamin d supplementation programmes across europe and factors influencing adherence vitamin d and health in pregnancy, infants, children and adolescents in australia and new zealand: a position statement adherence to vitamin d recommendations among us infants aged 0 to 11 adherence to complementary feeding recommendations for infants and implications for public health vitamin d and childhood asthma: 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receptor negatively regulates bacterialstimulated nf-κb activity in intestine the association between gut microbiota development and maturation of intestinal bile acid metabolism in the first 3 y of healthy japanese infants rapid change of fecal microbiome and disappearance of clostridium difficile in a colonized infant after transition from breast milk to cow milk five years experience of clostridium difficile infection in children at a uk tertiary hospital: proposed criteria for diagnosis and management maternal dietary folate, folic acid and vitamin d intakes during pregnancy and lactation and the risk of cows' milk allergy in the offspring maternal micronutrients can modify colonic mucosal microbiota maturation in murine offspring impact of maternal nutrition on breast-milk composition: a systematic review harmonization of food-frequency questionnaires and dietary pattern analysis in 4 ethnically diverse birth cohorts postnatal exposure to household disinfectants, infant gut microbiota and subsequent risk of overweight in children food nutrition board. dri dietary reference intakes calcium vitamin d use of micronutrient supplements among pregnant women in alberta: results from the alberta pregnancy outcomes and nutrition (apron) cohort: supplement use during pregnancy the current recommended vitamin d intake guideline for diet and supplements during pregnancy is not adequate to achieve vitamin d sufficiency for most pregnant women the canadian healthy infant longitudinal development (child) study: examining developmental origins of allergy and asthma open-source sequence clustering methods improve the state of the art vitamin d and calcium: updated dietary reference intakes vitamin d -effects on skeletal and extraskeletal health and the need for supplementation applied logistic regression: chapter 4 dysfunction of the intestinal microbiome in inflammatory bowel disease and treatment key: cord-348567-rvwxysvc authors: panfili, f. m.; roversi, m.; d’argenio, p.; rossi, p.; cappa, m.; fintini, d. title: possible role of vitamin d in covid-19 infection in pediatric population date: 2020-06-15 journal: j endocrinol invest doi: 10.1007/s40618-020-01327-0 sha: doc_id: 348567 cord_uid: rvwxysvc purpose: covid-19 is a pandemic of unprecedented proportion, whose understanding and management is still under way. in the emergency setting new or available therapies to contrast the spread of covid-19 are urgently needed. elderly males, especially those affected by previous diseases or with comorbidities, are more prone to develop interstitial pneumonia that can deteriorate evolving to ards (acute respiratory distress syndrome) that require hospitalization in intensive care units (icus). even children and young patients are not spared by sars-cov 2 infection, yet they seem to develop a milder form of disease. in this setting the immunomodulatory role of vitamin d, should be further investigated. methods: we reviewed the literature about the immunomodulatory role of vitamin d collecting data from the databases medline and embase. results: vitamin d proved to interact both with the innate immune system, by activating toll-like receptors (tlrs) or increasing the levels of cathelicidins and β-defensins, and adaptive immune system, by reducing immunoglobulin secretion by plasma cells and pro-inflammatory cytokines production, thus modulating t cells function. promising results have been extensively described as regards the supplementation of vitamin d in respiratory tract infections, autoimmune diseases and even pulmonary fibrosis. conclusions: in this review, we suggest that vitamin d supplementation might play a role in the prevention and/or treatment to sars-cov-2 infection disease, by modulating the immune response to the virus both in the adult and pediatric population. the recent epidemic of covid-19 has rapidly become an emergency threat for the health systems of all infected countries by overloading the medical facilities and intensive care units and causing thousands of deaths. in order to allow the national health systems to organize and set more beds, devices and medical personnel, the local governments have taken extraordinary measures to restrain the spread of the epidemic, including limitation of individual movements, shutdown of all less necessary economic activities and isolation of areas and cities where the epidemic has clustered. given the dire circumstances, the efforts of the researchers have been focused on the prevention and treatment of this disease. nonetheless, while the development of new drugs or vaccines would take a long time before human testing and commercialization, clinical trials on available pharmaceuticals with a potential effect against covid-19 could more easily yield useful results and, as a matter of fact, are already being performed. vitamin d is usually known for its role in the maintenance of bone health and calcium-phosphorus metabolism, yet many other roles of this hormone have been recently discovered, such as modulation of the immune response in both infectious and autoimmune diseases. just recently, it is being hypothesized that vitamin d supplementation could be used as a preventive or event therapeutic option in covid19 , but more studies are needed to validate this association. in the following, we describe vitamin d immunomodulatory role and effect on some infectious filippo m. panfili and marco roversi have contributed equally to the manuscript. and autoimmune diseases that might share similarities with covid-19, based on the current and future understanding of the pathogenesis of this infection. in december 2019, an epidemic of pneumonia caused by a novel virus later identified as severe acute respiratory syndrome coronavirus 2 (sars-cov-2) started in the city of wuhan, hubei province, china. recently, the world health organization (who) has declared coronavirus disease 2019 , a pandemic of global health concern. most people infected by sars-cov-2 develop interstitial pneumonia with ground-glass opacities at the ct scan, while a minority of patients develop acute respiratory distress syndrome (ards), and need hospitalization in intensive care units (icus). as of april 13, 2020, a total of 1,773,084 laboratoryconfirmed cases and 111,652 deaths have been documented [1] . in italy, the first european country to deal with a rapid increase in the number of covid-19 cases in the last month, the epidemic is cornering the national health system (ssn), which usually provides high-level and free-for-all health care. despite the total shutdown of the country to limit the spread of the epidemic and the increasing of icu personnel, devices, and beds are timely met, the recent estimates predict a gloomy development of the epidemic, with clinical facilities at their maximum load and intensive care specialists forced to allocate the life-saving care to the youngest and fittest [2] . that is, making the uncomfortable choice between who lives and who dies. the demographics of the covid-19 outbreak proves that elderly males, with or without comorbidities, are the most severely affected across all populations. in a large report of 72,314 cases from the chinese center for disease control and prevention [3] , 87% of cases were aged 30-79 years and 3% were aged 80 years or more, with a case-fatality rate of 8% and 14.8%, respectively. critical disease requiring admission in icu and mechanical ventilation was observed in 5% of all cases, with a case-fatality rate of 49%. in a sample of 1099 laboratory-confirmed cases of covid-19 [4] 41.7% of patients were females and 0.9% of patients were 14 years old or younger. although children appear to be the least affected across all ages, they might still be responsible of the transmission of the virus. in a cohort of 171 pediatric cases of covid-19 [5] up to 15.8% of patients did not have any symptoms of infection or radiologic features of pneumonia and 7% of these patients had radiologic features of pneumonia without presenting any clinical sign. in a report on 2.143 pediatric cases of covid-19 more than 90% of patients with clinically or laboratory diagnosed infection had asymptomatic, mild, or moderate disease. half of the 10% critical cases of covid-19 in this study were less than 1 year of age [6] . most people depend on sunlight exposure to produce the required amount of vitamin d [7] . differences in sunlight-dependent production of vitamin d is greatly influenced by season, latitude, time of day, skin pigmentation, sunscreen use, and age, with the elderly generating 25% of the vitamin d produced by younger ones in the same amount of time. as very few nutrients naturally contain vitamin d, dietary intake of vitamin d is generally insufficient. thus, fortification of food and/or oral supplementation is often necessary. in adults, vitamin d supplementation is recommended for all ages (600 ui/day from 19 to 70 years of age; 800 ui/day > 70 years of age; up to 1500/2000 ui/day to maintain a blood level of vitamin d above 30 ng/ml), with a higher dosage required for pregnant or lactating women and subjects at risk of osteoporosis [8] . in the pediatric population, vitamin d supplementation (400 ui/day from birth to 12 months of age and 600 ui/day beyond 12 months of age) is usually recommended for the prevention of rickets and osteomalacia [9] . the ultraviolet b radiation is absorbed by 7-dehydrocholesterol in the skin, leading to its conversion to previtamin d3, which is rapidly transformed into vitamin d3 (cholecalciferol). the molecule then undergoes further processing in the liver [25-hydroxycholecalciferolorcalcifediol] by cytochrome cyp2r1 and in the kidney (1,25-dihydroxy cholecalciferol or calcitriol) by cytochrome cyp27b1, before reaching its cellular targets. here, the activated vitamin d binds to the nuclear vitamin d receptor (vdr) and forms an heterodimeric complex with the retinoic acid x receptor that recognizes specific dna sequences, known as vitamin d responsive elements (vdre), resulting in the expression of the vitamin d responsive genes via a variety of transcriptional factors (fig. 1 ). although vitamin d is usually acknowledged for the maintenance of bone health and calcium-phosphorus metabolism, many other roles of this hormone have been recently discovered, such as stimulation of insulin production, effects on myocardial contractility, prevention of inflammatory bowel disease (ibd), and promotion of thyroid-stimulating hormone (tsh) secretion. furthermore, the immunomodulatory role of vitamin d has been the subject of several studies [10] . to date, it is known that the vdr activation can regulate the expression of more than 900 genes, many of which are involved in innate and adaptive immunity. vdr is expressed in almost all immune cells, including activated cd4+ and cd8+ t cells, b cells, and antigen-presenting cells, such as macrophages and dendritic cells. the receptor acts as a modulator of innate and adaptive immunity [11] . it is also known that vitamin d enhances the expression of two antimicrobial peptides called cathelicidin and β-defensin, and that play a key role in innate immunity [12, 13] . these peptides are involved in direct microbicidal effects and have also shown pleiotropic effects in inducing immunomodulatory responses to pathogen stimuli. in particular, human cathelicidin peptide ll37 exhibits a variety of effects, through interacting with formyl peptide receptor-like 1 (fprl1), recruiting neutrophils, monocytes, and t cells to infectious sites. it also promotes apoptosis of infected cells and showed a potent antiviral effects on a variety of viruses, such as hiv-1, influenza viruses, hsv1-2, rhinovirus, and hcv [14] . a number of studies reported a high prevalence of vitamin d deficiency among hiv-infected individuals. more specifically, faster hiv progression and severity, lower cd4+ counts, increased risk of mortality, and increased vulnerability to mycobacterium tuberculosis were reported [15] . although the effect of normal to high levels of vitamin d on increasing cd4+ count is still unclear, a recent review proved that vitamin d plays an important role in reducing the immune activation of hiv-infected patients. in particular, the paper reports that supplementation with a daily dose of vitamin d between 4000-7000 iu for at least 12 weeks can reduce the expression of cd38 and ki67 in cd8+ t lymphocytes, inflammatory monocytes (cd14+ cd16+), as well as the expression of pd1 + (an exhaustion marker) in cd4+ t cells, with an increase in cd4+/cd8+ t cell ratio. this leads to the important assumption that brisk supplementation in vitamin d-deficient hiv-infected patients could help reduce chronic inflammation and comorbidities [16] that are still frequent among these patients despite the constant amelioration of combination antiretroviral therapy (cart) [17] . human cathelicidin peptide ll37 also modulates the recognition of viral dsrna by toll-like receptor 3 (tlr 3). it is known that activation of toll-like receptors (tlrs) generate antimicrobial activity against intracellular pathogens and it has been demonstrated that tlr activation expressed by human macrophages can upregulate the expression of vitamin d receptor and vitamin d-1-hydroxylase genes, leading to the production of antimicrobial peptide (cathelicidin) and stimulate the intracellular killing of mycobacterium tuberculosis [13] . vitamin d also promotes selftolerance by shifting the cytokine patterns from a th-1 to a th-2 environment. this results in a reduction in th1-and in this picture, we resumed on the left side the principal functions of vitamin d. in particular, we enlightened the anti-proliferative and anti-inflammatory function on adipose tissue, the anti-fibrotic effect on lung tissue, the inhibition of the aromatase enzyme with subsequently reduction in estradiol, the preventing role in developing autoimmune diseases and its immunomodulatory role on the innate and adaptive immune systems. on the right side, it is shown the "cytokine storm" caused by sars-cov-2. we highlighted also the possible interaction role of dpp-4/cd 26-r, reduced by supplementation of vitamin d with sars-cov-2. ace-2 angiotensin-converting enzyme-2, rxr retinoid x receptor, tlrs toll-like receptors, vdr vitamin d receptor, vdre vitamin d response element, wbc white blood cell th17-stimulating cytokines with depletion of th-17 cells (which are known to be linked to tissue damage and inflammation) and upregulation of regulatory type-2 (t reg) cells [18] . it has also been demonstrated that vitamin d is capable of inducing autophagy and apoptosis in infected cells, throughout several mechanisms [14] . finally, 25-hydroxyvitamin d and 1,25(oh)2d also modulate t-cell immunity, reducing pro-inflammatory type 1 cytokines (such as, il-8, ifn-γ, il-12, il-6, tnf-α, and il-17) and increasing antiinflammatory type 2 cytokines (such as, il-4, il-5, and il-10) [19] . more specifically, 1,25(oh)2d inhibits proliferation of plasma cell and immunoglobulin secretion, and it induces b cell apoptosis [20] . in summary, many studies have demonstrated the immunomodulatory influence of vitamin d both in adult and pediatric patients, by enhancing and coordinating the innate and adaptive response in different pathologic conditions (table 1 ). several studies have demonstrated that higher levels of vitamin d are associated with better prognosis and outcome in infectious diseases [12] . indeed, vitamin d has been extensively studied as a putative preventive and therapeutic agent for acute respiratory tract infections (artis) in both adults and children, especially in developing and low-income countries, owing to its safety and low cost. as a matter of fact, pneumonia is the leading cause of death in children in the world [21] . a great number of studies have hypothesized a positive correlation between vitamin d deficiency and the risk of developing artis [22] . however, the link between vitamin d deficiency and acute respiratory infections occurring during the winter season, despite being frequently brought up in the literature, has not been unequivocally confirmed [23] . moreover, discrepancies between different age groups have been observed. vitamin d supplementation, as already described, seems to decrease proinflammatory cytokines in the lung via modulation of both macrophages and t lymphocytes activity [24] . in a recent meta-analysis, including 25 randomised controlled studies (rcts), it has been demonstrated that vitamin d supplementation reduced the risk of developing acute respiratory tract infections, with a higher protective effect in those who received weekly vitamin d supplementation or in those with low levels of vitamin d at baseline (25-hydroxyvitamin d levels < 25 nmol/l) [25] . while it is supposed that serum levels of vitamin d between 20 ng/ml and 50 ng/ml should be adequate to provide an immunomodulatory effect, there has been great uncertainty on the vitamin d supplementation regimen to adopt [26] . a recent systematic review studied the role of vitamin d as an adjunctive therapy to antibiotics in acute childhood pneumonia. it included seven rcts conducted in low-income countries that involved 1529 children. nonetheless, owing to the different supplementation regimens adopted for each study and the lack of reporting on the etiology of pneumonia, only low-to very low-quality evidence was made available [27] . in fact, its role as possible adjuvant to antibiotics treatment of acute childhood pneumonia has already been undetermined in a previous cochrane review [28] . a more recent study also showed how high-dose vs standard-dose wintertime vitamin d supplementation did not reduce viral upper respiratory tract infections in young healthy children [29] . nonetheless, the ineffectiveness of vitamin d in the younger might be due both to the lower prevalence of vitamin d deficiency, when compared with the elderly, and to a putative threshold effect of vitamin d in preventing arti. it has been, indeed, demonstrated that the negative correlation between levels of vitamin d and respiratory tract infections, should be attributed to its active form (1,25-oh2-vit d); therefore, restoring the levels of inactive vitamin d might not be sufficient in some patients, like those affected by chronic kidney or liver disease [30] . interestingly, it has also been demonstrated that vitamin d supplementation in patients with ventilator-associated pneumonia (vap) can significantly reduce il-6, that can be considered a prognostic marker, and the mortality rate in patients treated with vitamin d was significantly lower than that of the placebo group. the authors concluded suggesting the administration of vitamin d at a high intramuscular dose (300.000 ui) as an adjunct to the standard treatment of vap patients [31] . in a variety of animal models pretreatment with 1,25-oh2-d proved effective in mitigating or preventing the onset of type 1 diabetes mellitus (dm1), multiple sclerosis (ms), rheumatoid arthritis (ra), systemic lupus erythematosus (sle), crohn's disease, thyroiditis, psoriasis, polymyalgia rheumatica, and autoimmune gastritis [7, 32] . an interesting study conducted on 12.555 subjects showed a statistically significant correlation between vitamin d status and development of autoimmune disease in danish population [33] . interestingly, in another study specific allelic variants of vdr (especially bsmi, apai, taqi, and foki polymorphism genotypes) have been associated with higher susceptibility to develop an autoimmune disease (i.e., bsmi and foki polymorphism for sle or apai, bsmi, and taqi polymorphisms for ra) [34, 35] . this is of particular interest and it could explain the variability of responses to vitamin d supplementation in autoimmune and infectious diseases across the different regions of the world [36] . a significant inverse correlation was reported between disease activity and serum vitamin d concentration in sle [37] . a preventive role of vitamin d has also been demonstrated in dm1. in this autoimmune disease using calcitriol supplementation reduces serum levels of antibodies and slows the progression of β cell destruction down in the early stages of the disease [38] , interestingly, it has also been demonstrated that in systemic sclerosis (ssc) [39] the vdr could act as a negative regulator of tgf-β/ hydroxyproline, col1a1, col3a1 and alfa-sma mrnas ↓ prevention of bleomycin-induced lung fibrosis in a murine model [48] smad signaling, thus making vitamin d a putative antifibrotic treatment in the early stages of the disease. although the immunoregulatory function of activated vitamin d has been widely demonstrated, its role in modulating disease activity in patients with autoimmune diseases, such as rheumatoid arthritis was only recently showed [40, 41] . in a german study on a selected cohort of patients with juvenile idiopathic arthritis (jia), vitamin d levels not only proved to be lower than those of their peers from the general population, but were also found to be inversely correlated with disease activity and the risk of progression to an extended disease course and/or jia-associated anterior uveitis [42] . however, many other studies could not demonstrate a significant inverse correlation between vitamin d levels and jia disease activity, probably owing to the diverse geographical origins of the patients and the lack of an established single measure that could serve as an accurate indicator of childhood disease activity [43] . although a sudden increase in the incidence of kawasaki disease (kd) was noted in the province of bergamo, italy, which was profoundly affected by the covid-19 epidemics [44] , another study reported a significant severe vitamin d deficiency in a cohort of 79 children with kd as compared to healthy controls, and low levels of vitamin d seems to correlate to the risk in developing coronary artery aneurysms (p = 0.005) and non-aneurysmatic cardiovascular lesions (p < 0.05) [45] . moreover, vitamin d deficiency has been associated with resistance to intravenous immunoglobulin in kd (defined as persistent or recrudescent fever ≥ 36 h after the completion of the initial infusion), suggesting a potent immunomodulatory role of this vitamin [46] . of note, most of the aforementioned studies could not define the optimal concentration of 25(oh) d and the corresponding dietary requirements or treatment regimen suitable to the given disease. recently, it has been demonstrated that high levels of vitamin d (directly activated by respiratory tract cells through cyp27b1) could reduce pulmonary fibrosis by decreasing the levels of pro-inflammatory cytokines (il-1 beta) produced by pulmonary fibroblast cell lines in a mouse model of bleomycin-induced lung fibrosis [47] . in another study vitamin d administration prevented bleomycin-induced lung fibrosis in mice, by decreasing the levels of hydroxyproline and col1a1, col3a1, and alfa-sma mrnas [48] . in the same study, pretreatment with vitamin d reduced profibrotic stimuli and restored tgfb1-induced downregulation of vdr mrna levels. elsewhere, vitamin d deficiency proved to activate the ras pathway with induction of tgf b-1 [49] . another pathway inhibited by 1,25 (oh2) vitamin d [50] is the wnt/beta-catenin signaling, which has also been reported as involved in pulmonary fibrosis. the demographics of the covid-19 outbreak proves that elderly males, with or without comorbidities, are the most affected across all populations. the available data on the epidemic are also showing a lesser involvement of vast areas lying in the tropics. although this could easily relate to the lower median age of the population of developing countries, it is harder to make such an inference when looking at the markedly slow march of the covid-19 epidemic in countries of the southern hemisphere, such as australia [51] . just recently [52] , it has been directly hypothesized that vitamin d supplementation could be used as a therapeutic combination in covid-19, based on the epidemiology of the disease, and on the decreased vitamin d status observed in calves infected with bovine coronavirus [53] . in the emergency setting that followed the spread of the covid-19 pandemic new therapeutics have been empirically administered on the basis of former experience in the management of diseases sharing a few similarities with covid-19-associated ards, such as inflammatory autoimmune diseases. a growing interest in the role of tocilizumab, a monoclonal antibody directed against interleukin-6 (il-6), which is commonly used in the treatment of rheumatoid arthritis, ensued the publication of works regarding its potential use in the prevention of severe cytokine release syndromes, such as in car-t cell treated pediatric oncologic patients [54, 55] . this so-called cytokine storm has been postulated and confirmed [56] as the main responsible for the lethal pulmonary involvement that is being observed in covid-19 and was thoroughly studied in former 2009 sars epidemic [57] . in order to confirm tocilizumab therapeutic potential in ventilator-assisted covid-19 patients, a clinical trial is currently ongoing in china [58] and in europe [59] . just recently, normal to high blood levels of vitamin d proved to act synergistically with tocilizumab in patients with rheumatoid arthritis by suppressing il-6 enhanced osteocyte-mediated osteoclastogenesis and reducing disease activity [60] . although the data on covid-19 survivors are still lacking, a further downside of the pandemic might be the development of pulmonary fibrosis, which has been widely described as a common complication of ards [61] . here, vitamin d supplementation before and after the infection could play an antifibrotic role that yet need to be delved into. finally, we would highlight some points that should be further investigated. there is, in fact, a vast literature that shows how obesity in children is closely related with low levels of vitamin d, reaching the prevalence of 92% in the united states. interestingly, in a recent review, it was also showed that increased adipose tissue, altered adipocyte function and development of adipocyte hypertrophy is linked to an altered adipokine secretion profile, with increase in tnf-alpha, il-6, and il-1b levels. even more interestingly, the study proved that patients receiving long-term vitamin d supplementation had a reduction in adipose tissue inflammation by inhibition of tnf-alpha activity [62] . prepubertal children have generally lower androgen levels, with an elevated estrogen to androgen ratio. it has been demonstrated that low estrogen levels are related with an increased il-1beta, il-6, and tnf, increased activity of th1 cells and high androgen levels are related with an increase in il-1beta, il-6, and a reduction in tnf, ifn-gamma, il-4, il-5, gata3. it is also clear that sex hormones can differentially influence, along with other genetic polymorphisms and environmental factors, development of innate and adaptive immune responses. in a murine model, the hormonal changes of puberty upregulated the expression of genes associated with innate and adaptive immune responses in males and females, respectively [63] . it has also been demonstrated that high levels of vitamin d seem to reduce aromatase activity (which is in turn increased by high levels of pro-inflammatory cytokines levels), thus containing the effects related to increased peripheral estrogen metabolism, such as b cell overactivity. that means that low levels of vitamin d can increase the risk of developing autoimmune diseases in young women [64] . till date, only one recent paper addressed the relationship between vitamin d levels and the clinical outcomes of patients with covid-19 [65] . the author conducted a multinomial logistic regression to explore the association between serum 25(oh)d level and clinical outcomes of 212 cases with laboratory-confirmed infection of sars-cov-2. interestingly, serum 25(oh)d proved to be a predictor of severe (or 0.126, p < 0.001) and critical (or 0.051, p < 0.001) covid-19. a recent review proposes the supplementation of vitamin d in covid-19 patients based on the promising findings of rcts conducted in other viral infections [66] . according to the emerging relationship between vitamin d status and alleged covid-19 infection, vitamin d supplementation has already been proposed elsewhere [67] . although we do not assume that vitamin d plays a role in the pathogenesis of covid-19, we do believe that its putative role in preventing or even treating the disease urgently needs to be further addressed. at the moment of writing, an interventional randomized clinical trial has been proposed at the university of granada, with enrollment of 200 participants, proposing vitamin d supplementations (a single dose of 25,000 ui of vitamin d) in preventing and treating mild forms of suspected covid-19 [68] . in a recent paper, it is assumed that vitamin d prophylaxis (without overdosing) could reduce, especially in patients with hypovitaminosis d, the severity of illness caused by sars-cov-2 [69] . the importance of treating the hypovitaminosis d along with an early nutritional supplementation has been highlighted for the potential preventing role of malnutrition sequelae in these patients [70] . on the basis of the possible direct and indirect effect of vitamin d on immune system and cytokines production, we speculate a possible influence of this vitamin on the immunologic response to the virus and/or a modulating effect on the drugs being administered, namely hydroxychloroquine and anti-il 6 and anti-il 1 agents. author contributions dr fmp conceptualized and designed the article, collected data, drafted the initial manuscript, and reviewed and revised the final manuscript. dr mr conceptualized and designed the article, drafted and wrote the manuscript, and reviewed and revised the final manuscript. dr df conceptualized and designed the article, coordinated and supervised data and reviewed and revised the final manuscript. dr mc critically reviewed the manuscript for important intellectual content. dr pd reviewed the manuscript for important intellectual content. prof pr reviewed the manuscript for important intellectual content. all authors approved the final manuscript as submitted and agree to be accountable for all aspects of the work. funding no funding was secured for this study. conflict of interest the authors have no financial relationships relevant to this article and no conflict of interest to disclose. cledoes not contain any studies with human participants or animals performedby the sole author d. fintini. informed consent for this type of study, informed consent is notrequired. world health organization. coronavirus disease (covid-19) outbreak 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endocrinol sex differences in immune responses vitamin d, steroid hormones, and autoimmunity vitamin d supplementation could possibly improve clinical outcomes of patients infected with coronavirus-2019 (covid-19) evidence that vitamin d supplementation could reduce risk of influenza and covid-19 infections and deaths optimisation of vitamin d status for enhanced immuno-protection against covid-19 2020 apr 3-identifier nct04334005, effect of vitamin d administration on prevention and treatment of mild forms of suspected covid-19 (covitd-19) letter: covid-19, and vitamin d early nutritional supplementation in non-critically ill patients hospitalized for the 2019 novel coronavirus disease (covid-19): rationale and feasibility of a shared pragmatic protocol key: cord-337849-tyabf12r authors: greiller, claire l.; martineau, adrian r. title: modulation of the immune response to respiratory viruses by vitamin d date: 2015-05-29 journal: nutrients doi: 10.3390/nu7064240 sha: doc_id: 337849 cord_uid: tyabf12r background: vitamin d deficiency has been shown to be independently associated with increased risk of viral acute respiratory infection (ari) in a number of observational studies, and meta-analysis of clinical trials of vitamin d supplementation for prevention of ari has demonstrated protective effects. several cellular studies have investigated the effects of vitamin d metabolites on immune responses to respiratory viruses, but syntheses of these reports are lacking. scope: in this article, we review the literature reporting results of in vitro experiments investigating immunomodulatory actions of vitamin d metabolites in human respiratory epithelial cells infected with respiratory viruses. key findings: vitamin d metabolites do not consistently influence replication or clearance of rhinovirus, respiratory syncytial virus (rsv) or influenza a virus in human respiratory epithelial cell culture, although they do modulate expression and secretion of type 1 interferon, chemokines including cxcl8 and cxcl10 and pro-inflammatory cytokines, such as tnf and il-6. future research: more studies are needed to clarify the effects of vitamin d metabolites on respiratory virus-induced expression of cell surface markers mediating viral entry and bacterial adhesion to respiratory epithelial cells. viral acute respiratory infections (ari) are a leading cause of morbidity and mortality worldwide, and, as such, are a major global health problem. they are also responsible for a huge economic burden, precipitating considerable absence from work and school, and large numbers of visits to clinicians. the viral pathogens most commonly associated with acute respiratory infections are picornaviruses (including the species rhinovirus (rv) a, rvb, rvc and the enteroviruses a-d), orthomyxoviruses (influenza a, influenza b and influenza c), paramyxoviruses (including the parainfluenza viruses (piv) 1-4, respiratory syncytial virus (rsv) and human metapneumovirus (hmpv)), coronaviruses, adenoviruses and human bocavirus (hbov) [1] [2] [3] [4] [5] . the only routinely administered vaccine for a viral respiratory pathogen in the uk is against seasonal influenza: this is not 100% effective and may offer varying levels of protection against influenza infection in different seasons and different age groups [6] . the availability of effective antiviral drugs is also limited, with the effectiveness of approved influenza treatments, such as oseltamivir (tamiflu), debated [7] [8] [9] , and no clinical treatments for common respiratory viruses such as rhinoviruses. new agents to prevent and treat viral respiratory infection are needed: the who initiative brave (battle against respiratory viruses) has recently been established to aid in the goal of developing new pharmacologic interventions to prevent and treat respiratory viruses [10] . vitamin d is an immunomodulatory micronutrient [11, 12] . as reviewed elsewhere [13] , a number of observational studies have been carried out to determine the relationship between vitamin d status and acute respiratory viral infections, with the majority demonstrating independent associations between low vitamin d status and increased risk of acute viral respiratory infections. clinical trials of vitamin d supplementation for the prevention of ari have yielded heterogeneous results [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] , with meta-analysis reporting moderate protective effects overall [28] . a number of in vitro studies have investigated the effects of vitamin d metabolites on host immune responses to respiratory viruses, but recent syntheses of this literature are lacking. in order to review these studies the pubmed database was searched using the terms "vitamin d" with the following respiratory viruses (rhinovirus, rsv, influenza, parainfluenza, human metapneumovirus, coronavirus, adenovirus, enterovirus and human bocavirus) to ensure a systematic review of the available literature. inclusion criteria were studies which provided in vitro evidence as opposed to solely clinical studies, the availability of the full text, and for virus genera, such as enterovirus, which can infect multiple sites, the use of species or serotypes specifically associated with respiratory disease. when a respiratory virus is inhaled it first binds to non-specific receptors on the respiratory epithelium, usually glycolipids or glycoproteins such as intercellular adhesion molecule (icam)-1. membrane fusion or endocytosis follows, thus internalizing the virus and enabling subsequent replication, transcription and translation of new viruses which can then be released to infect new cells. however, once a cell has been infected, pathogen-associated molecular patterns (pamps) on the virus can be recognised by various intracellular innate pathogen recognition receptors (prrs) such as the toll-like receptors (tlrs), retinoic-acid-inducible gene-i (rig-i)-like receptors (rlrs) and nucleotide binding-oligomerisation domain (nod)-like receptors (nlrs). pulmonary epithelial cells have been shown to express all of the known human tlrs and rlrs which detect viruses, and ligands for these prrs activate epithelial cells in order to initiate a rapid immune response against viral invasion [29] . in addition to direct infection of epithelial cells, intraepithelial dendritic cells (dcs), dcs residing just below the respiratory epithelium, and tissue-resident macrophages continually sample particles in the airway lumen and can internalize them by phagocytosis and macropinocytosis, thus activating prrs and initiating an immune response [30, 31] . the intracellular tlrs 3, 7, 8 and 9 are mainly located on the endoplasmic reticulum (er) membrane before unc93b1-dependent (an er multi-transmembrane-domain-containing protein) trafficking to the endolysosome following viral infection [32, 33] . these nucleic acid-sensing tlrs recognise single-stranded rna (tlr 7/8) or unmethylated cpg double-stranded dna motifs (tlr 9) of the viral genome, or the intermediary double-stranded rna (tlr 3) produced during viral replication [34] [35] [36] [37] . additionally, tlr4 and tlr2 receptor complexes are able to traffic to the endolysosome and may play a role in viral recognition [37] [38] [39] [40] [41] . viruses which avoid recognition by tlrs, can be recognised by rlrs which are present throughout the cytosol, with rig-i important in the immune response to many rna viruses [42] , and melanoma differentiation-associated gene 5 (mda5) crucial in the recognition of picornaviruses [43] . additionally, the cytosolic nlr nod2, whilst normally associated with the recognition of bacterial muramyl dipeptide, has also been demonstrated to be involved in the recognition of the ssrna genome of rsv [44] . despite differences in viral genomes, replication strategies, and the types of prrs activated, common signalling pathways are utilized. thus recognition of viral pathogens elicit conserved outcomes, with the interferon regulatory factor (irf)-mediated production of type i ifns a central feature, along with nuclear factor kappa b (nf-κb)-and mitogen-activated protein kinase (mapk)-mediated regulation of various inflammatory cytokines [37, 45] (figure 1 ). upon pamp-prr interaction and the activation of signalling transduction pathways, the type i ifns (ifn-α and ifn-β) are some of the earliest cytokines to be produced. their transcription and subsequent binding to the ifn receptor induces expression of a variety of interferon-stimulated genes (isgs), with their products altering antiviral and immunomodulatory actions to limit and clear infection [45] . features of the induced anti-viral state include resistance to viral replication in all cells, induction of apoptotic cell death in infected cells, increased major histocompatibility complex (mhc) class i expression to enhance antigen presentation, activation of dendritic cells (dcs) and macrophages, and stimulation of natural killer (nk) cells to enhance their cytolytic activity [46] . the inflammatory cytokines tnf-α, il-1β, il-6 and il-12 are also produced at an early stage of the innate immune response. these cytokines promote leukocyte extravasation by increasing endothelial expression of adhesion molecules, such as icam-1 and vcam-1, increase vascular permeability, induce synthesis of acute phase proteins, and contribute to recruitment and activation of cells of the adaptive immune response. additionally, il-1β and tnf-α amplify the inflammatory response by triggering further nf-κb and mapk activation [47] . pathogen recognition receptor signalling following viral infection. ligand-induced dimerisation occurs following pamp recognition by endosomal tlrs, which engages the toll-il-1 receptor (tir) domains to initiate adaptor molecule recruitment and signal transduction. myd88-dependent signalling results in the formation of an irak/traf6 complex, which phosphorylates irf7 to initiate transcription of type i ifn genes, and activates a tak1/tab2/3 complex to drive transcription of pro-inflammatory cytokine genes via activation of nf-κb, ap1 and creb. trif-dependent signalling can also activate nf-κb, ap-1 and creb via recruitment of traf6 and rip1. alternatively, traf3 is recruited, resulting in phosphorylation of irf3 which translocates into the nucleus to induce expression of type i ifns. rig-i and mda5 are also able to activate nf-κb and irf3 via interaction with ips-1 localized on the mitochondrial membrane through homophilic interactions between their card domains. similarly, card domains of nod2 also interact with ips-1 resulting in transcription of type i ifn genes. the type i ifns produced bind to their receptor, and, via stat-mediating signalling, initiate gene transcription. innate prr signalling also results in the production of the chemokines cxcl8, cxcl9, cxcl10 and il-15 which facilitate recruitment of neutrophils and nk cells, respectively [48, 49] . while neutrophils and macrophages have well-defined roles in bacterial innate immunity, their function in antiviral immunity is less clear and is likely to be minimal, with inhibition of neutrophil recruitment to the lung demonstrated to have no effect on the course of influenza infection [50] , and the antigen presenting capacity of macrophages in the respiratory tract demonstrated to be limited [51, 52] . the antimicrobial peptide ll-37, which is produced by both neutrophils and macrophages, is traditionally viewed as a component of the immune response to bacteria. however, anti-viral activity of ll-37 has also been demonstrated against both enveloped and non-enveloped viruses, including influenza virus and rsv [53] . it has been shown to disrupt the membrane of influenza virus [54] , modify cytokine production [54] , enhance tlr3 signalling [55] , and have direct effects on rsv viral particles and infected epithelial cells, with diminished spread of infection and inhibited production of new virus particles [56] . macrophages may also have a critical role in the resolution of inflammation and clearance of infection to prevent immunopathology. they are able to phagocytose infected cells and apoptotic cellular debris, which, if left in the lumen, can release chemokines, such as cxcl9 and cxcl10, resulting in recruitment of inflammatory cells and increased bystander tissue damage. in the absence of alveolar macrophages, or when macrophages have impaired function, airway occlusion can occur following rsv infection due to the accumulation of inflammatory cells, virus-infected cells, apoptotic debris and serum proteins, resulting in severe and potentially fatal bronchiolitis [57] . similarly, following influenza infection in mice devoid of alveolar macrophages, pulmonary alveolar proteinosis (pap) was demonstrated owing to the accumulation of surfactant material and a failure in efferocytosis, causing impaired gas exchange and fatal hypoxia [58] . therefore, macrophages appear to have a vital role in the antiviral immune response, by producing antimicrobial peptides during the innate response, and phagocytosing dead cells and cellular debris to prevent immunopathology. prr signalling facilitates the maturation and trafficking of dendritic cells, with the release of the chemokines ccl2 and ccl20, and increased expression of ccr7 [59, 60] . thus, around 72 h after infection, dcs with antigen-mhc complexes migrate through the afferent lymph vessels to secondary lymph nodes where they form interactions with naive cd4 + and cd8 + t lymphocytes. these t-lymphocytes are activated, proliferate, differentiate into effector t-cells and migrate via efferent lymph vessels into the circulation. multiple chemokines, such as ccl3, cxcl9 and cxcl10, are expressed in the respiratory epithelium and result in changes in integrin affinity, allowing effector t-cells to bind to the endothelium and migrate into the infected tissue [37, [61] [62] [63] [64] . for efficient and effective viral clearance th1 effector t-cells are required, which produce il-2, tnf-α and ifn-γ to activate nk cells and induce generation of cytolytic molecules. cd8 + effector t-cells and nk cells can then induce apoptosis of infected cells via the release of cytolytic granules or by direct interaction between surface fas receptor and fas ligand (fasl) [37] . b-cells have also been demonstrated to play an important role in the immune response to highly pathogenic viral infections. contact between cd4 + t-cells and naive b-cells in secondary lymphoid tissues results in their proliferation and antibody class-switching, with neutralizing virus-specific antibodies crucial for optimal viral clearance. additionally, viral components expressed on infected cells allow antibodies to bind, thus initiating antibody-dependent cell-mediated cytotoxicity (adcc), whereby cd16 on nk cells recognises the fc portion of antibodies bound to the surface and kills the target cell [37, [65] [66] [67] . complement is also increasingly being recognised as an important component of anti-viral immunity, as reviewed elsewhere [68] . the evolution of evasion mechanisms by viruses emphasises the importance of complement in anti-viral immunity, with, for example, the matrix protein m1 of influenza a able to bind to c1q to prevent interaction with antibodies on the surface of infected cells [68, 69] . therefore, combined, these effector mechanisms of the adaptive immune response rapidly clear the viral infection. vitamin d (cholecalciferol) is acquired from dietary sources, primarily oily fish, or from uv-mediated synthesis in the skin, before it is metabolised in the liver to form 25(oh)d3. this 25(oh)d3 is the circulating form of vitamin d, with a half-life estimated to range from two weeks to two months [70] [71] [72] , and its serum concentration is used to define vitamin d status. further hydroxylation results in the synthesis of 1α,25(oh)2d3 and ligation of nuclear vitamin d receptors (vdrs), allowing subsequent binding to vitamin d responsive elements (vdres) in promoter regions of specific genes, resulting in the repression or induction of gene transcription [11] (figure 2 ). vdrs have also been shown to be located within the plasma membrane or its caveolae components [73] [74] [75] , with ligation resulting in 1α,25(oh)2d3-mediated non-genomic rapid responses via the activation of second messenger systems, such as phospholipase c, protein kinase c and phosphatidylinositol-3′kinase (pi3k), thus initiating various intracellular effects, such as the opening of voltage-gated calcium channels and ras/mapk signal transduction [75, 76] . the detection of vdr abundance throughout the immune system, the observation that vdr expression is regulated by immune signalling, and the detection of cyp27b1 expression by immune cells has directed vitamin d research into the area of immunology [77] [78] [79] [80] [81] , with associations of low serum 25(oh)d3 levels seen with autoimmune diseases, cancer, cardiovascular disease and respiratory infections [82] [83] [84] [85] . significantly, a link has been made between tlr ligation and cytokine secretion, the expression of cyp27b1 and the expression of the vdr. in the absence of any influence by calcium homeostatic agents [86] [87] [88] , and with a defective negative feedback mechanism [89, 90] , extra-renal 1α-hydroxylation in cells such as monocytes and macrophages is regulated primarily by immune inputs. therefore, this renders the immune system responsive to circulating levels of 25(oh)d and allows the sustained and potentially beneficial production of 1,25(oh)2d during an immune response [90] . vitamin d metabolism in macrophages is linked to pathogen recognition, thus making it an integral part of the innate immune response [91] . ligation of the tlr2/1 heterodimer in macrophages has been demonstrated to up-regulate cyp27b1, and the tlr8 ligands cl097 and ssrna40 have also both been demonstrated to induce a dose-dependent increase in cyp27b1 mrna and protein expression in macrophages [92] . similarly, ligation of tlr4 by lps up-regulated cyp27b1 expression in monocytes [93, 94] . in dendritic cells, ligation of tlr4 by lps or monophosphoryl lipid a (mpla), and ligation of tlr3 by polyi:c induced expression of cyp27b1, altering dc migratory properties to allow their localisation into non-draining secondary lymphoid organs to present antigen peptides to cd4 + t-cells [79, [95] [96] [97] . similarly, in human tracheobronchial epithelial (htbe) cells, polyi:c stimulation and addition of live rsv were demonstrated to increase cyp27b1 expression, enhance 25(oh)d conversion to 1,25(oh)2d, and amplify cathelicidin mrna [98] . with the expression of tlrs in multiple cell types, and the ability to respond to a variety of pathogens, it is also possible that other tlrs or alternate prrs may promote extra-renal expression of cyp27b1, allowing locally generated 1,25(oh)2d to have even more extensive effects on the immune response. the exact mechanism by which tlr ligation enhances cyp27b1 production has not been fully defined, although the jak-stat, nf-κb and p38 mapk pathways, and phosphorylation of the transcription factor c/ebpβ by p38 mapk have been implicated [94] . additionally, il-15 has been demonstrated to act as an intermediary in promoting localized activity of cyp27b1 and synthesis of 1,25(oh)2d. tlr 2/1 ligation by a triacylated lipopeptide of the m.tuberculosis 19 kda antigen in human monocytes induced il-15 secretion, which was required for the upregulation of cyp27b1 and the vdr, and subsequent downstream production of ll-37 [99] . other cytokines, such as il-13, ifnγ, il-4, il-1, il-2 and tnf-α, have also been implicated as regulators of cyp27b1 expression and vitamin d metabolism [87, 94, [100] [101] [102] [103] . the pathways involved in cytokine-regulated transcription of cyp27b1 are likely the same ones as utilized by tlr ligation-induced regulation, as described above [101] . therefore, extra-renal 1,25(oh)2d synthesis has been shown to be regulated by tlr ligation and cytokine secretion, utilizing an intricate cross-talk between various signalling pathways. as such, in the presence of sufficient circulating levels of 25(oh)d, infection by respiratory viruses resulting in recognition by tlrs and cytokine production is able to increase levels of 1,25(oh)2d, hypothetically altering the immune response to better respond to these pathogens. [104] , and parton and simons [105] ). vitamin d has diverse and extensive effects on the immune system, due to the expression of the vdr and the enzyme cyp27b1 by most immune cells [11, 77, 81, 106] . the most frequently demonstrated effect of vitamin d is that on ll-37, and, as such, its expression is commonly used to demonstrate increased cyp27b1 expression and 1,25(oh)2d activity. cathelicidins are multifunctional antimicrobial peptides, and the sole form in humans is human cationic antimicrobial peptide of 18kda (hcap-18). from this precursor, the active form of ll-37 is cleaved by serine protease 3 in neutrophils [107] . while the method of cleavage has not been demonstrated in other cells types, ll-37 has been shown to be present in epithelial cells, monocytes, nk cells, b-cells and γδ t-cells [56, 108] , and can be secreted by respiratory epithelial cells onto the airway surface to form a first line of defence against invading pathogens [109] . it has many functions, as described elsewhere [110] [111] [112] [113] [114] [115] , such as direct facilitation of chemotaxis of immune cells and modification of dc differentiation, and, while traditionally viewed as a component of only the immune response to bacteria, has also been shown to act directly against viruses [53, 54, 56] . numerous studies have demonstrated the role the 1,25(oh)2d-ligated vdr plays in binding to a vdre in the promoter of the cathelicidin gene to enhance hcap-18 production [116] [117] [118] [119] , thus suggesting a potential mechanism by which vitamin d may enhance innate immunity to respiratory infections. the proximal promoter region of defb4 gene also contains a vdre, allowing 1,25(oh)2d to upregulate expression of β-defensin 2 [116] . this is another antimicrobial peptide, which, similarly to ll-37, is able to induce chemotaxis of immune cells and has been shown to inhibit rsv infection [120, 121] . in addition to antimicrobial peptide induction, vitamin d has been demonstrated to modulate the innate immune system in a variety of other ways. monocyte differentiation into macrophages is induced [122] , with enhancement of the phagocytic and chemotactic capacity of macrophages [11, 123] , thus facilitating efferocytosis and preventing immunopathology. one of the signalling pathways regulated by vitamin d is the class iii phosphatidylinositol 3-kinase complex (pi3kc3), with pi3k signalling associated with monocyte and macrophage generation of ros and inos [124, 125] . the oxidative burst has been demonstrated to have beneficial antiviral effects [126] [127] [128] [129] , although aberrant induction is associated with pathophysiology and tissue damage [130] [131] [132] . as such, vitamin d may have an important role in redox homeostasis, with evidence of both pro-oxidative induction of ros and inos to boost the antiviral response [125, 133] , and antioxidative inhibition of inos and induction of ros scavenging pathways to prevent immunopathology [134] [135] [136] . the ability of 1,25(oh)2d to induce monocyte autophagy has also been demonstrated. autophagy acts as part of the immune system to remove damaged proteins and organelles, and is an important host defence mechanism against viral infections [137] . vitamin d has been shown to induce autophagy by regulating multiple associated pathways, such as bcl-2, mammalian target of rapamycin (mtor), class iii phosphatidylinositol 3-kinase complex, and cathelicidin production, thus potentially enhancing clearance of viruses and viral components [124, 138, 139] . pattern recognition receptors have also been demonstrated to be regulated by vitamin d. expression of tlr2 and tlr4 is inhibited in monocytes, resulting in impaired downstream signalling and hyporesponsiveness to pamps. with the observation that this effect is most prominent after 72 h, a negative feedback mechanism has been suggested, whereby excessive tlr activation is prevented at later stages of infection to dampen inflammation [11, 140] . conversely, cd14, an accessory protein to tlr4 which has also been linked to tlr2 [141] , was up-regulated by 1,25(oh)2d [140, 142, 143] , but this effect was not sufficient to restore downstream tlr signalling [140] . additionally, as opposed to its effects in monocytes, 1,25(oh)2d has been demonstrated to induce up-regulation of tlr2 in keratinocytes, allowing a mechanism by which vitamin d may prevent infection of wounds [144] . finally, the intracellular receptor nod2 is induced by 1,25(oh)2d in myeloid and epithelial cells, via two distal vdres in the nod2 gene. addition of mdp (a lysosomal breakdown product of bacterial peptidoglycan [11] ) to 1,25(oh)2d-induced nod2 enhanced nf-κb signalling and subsequent β-defensin 2 expression [145] . vitamin d also modulates the adaptive immune response, and acts as a key intermediary between innate and adaptive immunity due to its influence on antigen presentation. dendritic cells are the most potent antigen-presenting cells, and, as such, have a direct effect on lymphocyte activation and induction of the adaptive immune response. they reside in peripheral tissues in an immature state, sampling the environment and mediating antigen uptake, until a maturation signal induces migration to local lymph nodes and subsequent t-cell activation. addition of 1,25(oh)2d has been demonstrated to inhibit dc differentiation, maturation and antigen presentation, with an associated decrease in markers such as cd1a, mhc class ii, and the co-stimulatory molecules cd40, cd80 and cd86 [146] [147] [148] , as well as abrogating the chemotactic response to ccl4 and ccl19 [149] . already differentiated dendritic cells can also be redirected back towards a monocytic phenotype by the restoration of the monocytic marker cd14 [147, 150] . the antigen-presenting and t-cell stimulatory capacity of monocytes and macrophages is also impaired by 1,25(oh)2d, with a decrease in mhc class ii, cd40, cd80 and cd86. il-12 production is suppressed in both activated dcs and macrophages, due to the 1,25(oh)2d-mediated down-regulation of nf-κb activation [151] , while influence on the expression of tnf-α is dependent on the differentiation state of the cells, with a reduction observed following 1,25(oh)2d administration in lps-stimulated monocytes and pbmcs [140, 152] . the main function of dcs is to initiate t-cell responses, and thus the effect of 1,25(oh)2d on dcs has a major impact on t-cells. the decreased surface expression on dcs of co-stimulatory molecules and mhc class ii results in a tolerogenic phenotype, with dc production of il-12 (which is involved in driving th1 differentiation) and il-23 (which is involved in driving th17 differentiation) inhibited by 1,25(oh)2d [11, 150] . even when cultured with committed t-cells, these tolerogenic dcs caused hyporesponsiveness, decreased t-cell proliferation and reduced ifn-γ secretion [146, 153] . il-12, as well as stimulating the development of th1 t-cells, also inhibits the development of th2 cells, thus resulting in vitamin d shifting the balance of t-cells from a th1 to a th2 phenotype [154] . concomitantly, dc production of il-10 is increased. il-10 is a cytokine with pleiotropic effects in immunoregulation, and levels in bal fluid have been shown to be inversely correlated with severity/incidence of asthma [155, 156] . this il-10 production drives development of regulatory t-cells (tregs), and these tregs are able to secrete more il-10 as well as the immunomodulatory cytokine tgf-β, while release of the treg cytokine ccl22 is also increased [11] . th17 cells and il-17, have also been shown to be decreased, with calcitriol (1,25(oh)2d) reducing il-17 production in a mouse colitis model and impairing commitment to the th17 lineage in mice with experimental autoimmune uveitis [157, 158] , although these effects may not translate to the human respiratory system. th17 cells, by releasing il-17, initiate an inflammatory response dominated by neutrophils. while high levels of il-17 production are associated with chronic inflammation and severe immunopathology [159] , deficient levels, as seen in hyper-immunoglobulin e syndrome (hies), result in recurrent fungal and bacterial infections [160] . therefore, vitamin d may have a beneficial role in attenuating immunopathology caused by some infections, but be detrimental in other fungal and bacterial infections. 1,25(oh)2d has also been demonstrated to have direct effects on t-cells, independent of dc activity. while the role of dcs in the induction of tregs has been described, it has also been shown that 1,25(oh)2d in combination with dexamethasone can induce a treg population in the absence of apcs [161] . the proliferation and cytokine profiles of t-cells are also directly altered by 1,25(oh)2d. production of il-2, ifn-γ, tnf-α, il-17 and il-21 are all inhibited [157, 162, 163] , with inhibition of ifn-γ further precluding macrophage activation, thus attenuating antigen presentation and the recruitment of other t-cells [164] . this direct inhibition of th1-priming cytokines further skews t-cell differentiation towards a th2 phenotype. 1,25(oh)2d is also able to upregulate the th2-specific transcription factors gata-3 and c-maf, resulting in increased production of il-4, il-5 and il-10 [165] . b-cells are also affected by vitamin d, with modulation of t-cell responses altering the b-cell compartment, as well as having direct effects on b-cells themselves [11] . 1,25(oh)2d is able to inhibit proliferation, plasma-cell differentiation, immunoglobulin secretion and memory b-cell generation, while inducing b-cell apoptosis [80] . as such, vitamin d supplementation has been used in the treatment of b-cell-associated autoimmune diseases such as systemic lupus erythematous [166, 167] . finally, it has been suggested that vitamin d may affect other lymphocyte subsets, with vdr-ko mice presenting with fewer invariant natural killer (inkt) cells [168] , and cd8 + t-cells from ms patients secreting less ifn-γ and tnf-α and more il-5 and tgf-β following 1,25(oh)2d treatment [169] . however, the mechanisms behind any potential beneficial role of vitamin d are unclear, with conflicting cellular studies on the effects of vitamin d on th2 cells [170, 171] , with both enhancement [165] and inhibition [172] of il-4 synthesis demonstrated. 1,25(oh)2d has also been shown to down-regulate dc-derived ox40l, which is required for th2 priming, thus, resulting in a reduced th2 cytokine response in cd4 + t-cells from patients with allergic bronchopulmonary aspergillosis [173] , thus contradicting evidence that vitamin d skews the t-cell phenotype towards a th2 one. additionally, the decrease in th1 immunity which has been observed [11] would suggest a diminished immune response to pathogens, contrasting to the evidence suggesting an improved response to respiratory tract infections after vitamin d supplementation. finally, while studies have demonstrated direct effects of 1,25(oh)2d administration on lymphocytes, others have shown that when using the inactive metabolite 25(oh)d, dcs are required to convert this precursor to the active 1,25(oh)2d to exert its immunomodulatory effects [174] . this indicates that administration of different vitamin d metabolites may result in a different response. therefore, while vitamin d clearly acts as an immunomodulatory molecule with a wide range of effects demonstrated, the precise mechanisms are currently unclear, with the conflicting results reported also adding to the uncertainty of its actions. the main immunomodulatory effects of vitamin d are summarised in figure 3 . the innate immune response is affected, with monocytes producing more ll-37 and β-defensin, with increased nod2 expression and autophagy, while also producing diminished amounts of inflammatory cytokines, with decreased expression of tlr2 and tlr4. differentiation into macrophages is increased, with macrophages having an increased capacity for phagocytosis and chemotaxis. however, their apc and t-cell stimulatory capacity is decreased. monocyte and macrophage production of ros and inos is able to both be induced and inhibited, thus regulating their balance. differentiation into dcs is inhibited, with dcs expressing decreased levels of maturation surface markers. dc production of il-12 and il-23 is decreased, while mannose receptor expression and production of il-10 and ccl22 are increased. when these tolerogenic dcs interact with t-cells, development of tregs and th2 cells is increased, with increased production of il-10, tgf-β, il-4 and il-5. the development of th1 and th17 cells is inhibited, with decreased production of il-2, ifn-γ and tnf-α, and attenuation of macrophage activation. b-cells are also affected by 1,25(oh)2d, demonstrating decreased immunoglobulin production, proliferation and differentiation, but increased apoptosis. while a number of in vitro studies have described the general effects of vitamin d metabolites on the function of immune cells and secretion of inflammatory molecules, as described above, experiments investigating the specific antiviral effects of vitamin d on each respiratory virus are limited. the available literature is summarised below, and presented in figure 4 . rhinovirus infection of epithelial cells results in increased production and secretion of pro-inflammatory cytokines and chemokines, with the secretion of cxcl8 and cxcl10 further enhanced following treatment with 1,25(oh)2d. during rsv infection, iκbα expression is reduced, resulting in increased transcription of nf-κb-driven genes. stat1 is also phosphorylated and able to translocate into the nucleus resulting in increased expression of irf1 and irf7. pre-treatment with 1,25(oh)2d increases iκbα expression and decreases stat1 phosphorylation, resulting in decreased production of cxcl10, ifn-β, mxa, isg15, irf1 and irf7. similarly, influenza a infection causes increased expression of pro-inflammatory cytokines and chemokines, with 1,25(oh)2d treatment causing decreased expression of tnf-α, ifn-β, isg15, cxcl8, il-6 and ccl5. finally, 1,25(oh)2d is also able to increase ll-37 and hbd2 production, which have been shown to have antiviral effects against both rsv and influenza. rhinovirus is the most common aetiologic agent of the common cold, which in turn is the most frequent acute infection in the industrialised world, associated with two to three episodes per year in adults, and five to seven per year in children [175] [176] [177] . however, only one study has been carried out to determine the effect of vitamin d on rhinovirus infection [178] . experiments were carried out in which primary human bronchial epithelial cells (hbecs) were treated with 25(oh)d or 1,25(oh)2d and subsequently infected with rv-16. incubation with vitamin d metabolites had no effect on viral replication, and, whilst rv-16 infection induced hbec secretion of ccl5, il-6 and il-29, incubation with vitamin d metabolites did not alter this effect. treatment with vitamin d did, however, enhance secretion of cxcl8 and cxcl10, both in the presence and absence of rhinovirus infection. these molecules are pro-inflammatory chemokines, responsible for the recruitment of immune cells such as neutrophils, macrophages and t-cells to the site of infection, and could thus act as an effector mechanism as to how vitamin d alters the antiviral response to rhinovirus infection. rsv is usually associated with illness in young children, with most infants having been infected by the age of three, causing a mild uri for the majority, but severe bronchiolitis in some [179, 180] . it has also been associated with a higher risk of developing asthma in later life [181] . vitamin d deficiency has been linked to rsv susceptibility, with low cord blood plasma concentrations of 25(oh)d related to rsv incidence in the first year of life [182] , and single nucleotide polymorphisms (snps) in the vdr (rs10735810 and the fokl snp) and vitamin d binding protein (the gc1s variant) associated with a genetic predisposition to rsv bronchiolitis [183] [184] [185] [186] . however, as with rhinovirus, in vitro work investigating the specific effects of vitamin d on the immune response to rsv is limited. in a study using primary human tracheobronchial epithelial (htbe) cells treated with 1,25(oh)2d, expression of the nf-κb inhibitor iκbα was upregulated [187] . cells infected with rsv for 24 h had decreased protein levels of iκbα, due to rsv-induced degradation, but in cells pre-treated with 1,25(oh)2d prior to rsv infection iκbα levels were increased due to augmented mrna transcription and protein synthesis. an increase in iκbα results in nf-κb remaining inactive in the cytoplasm, preventing its translocation into the nucleus and subsequent binding to dna promoter regions. thus, vitamin d inhibits rsv induction of nf-κb-driven ifn-β and cxcl10 secretion, as also demonstrated in this study. additionally, interferon stimulated genes (isgs) without functional nf-κb sites in their promoters were also measured, with 1,25(oh)2d treatment resulting in decreased levels of human myxovirus resistance protein 1 (mxa) and isg15. this was demonstrated to be a consequence of the suppression of nf-κb-driven ifn-β production. similarly, pre-treatment with 1,25(oh)2d before inoculation with rsv resulted in decreased levels of stat1 protein and inhibition of stat-1 translocation to the nucleus, also as a consequence of suppression of nf-κb-driven ifn-β production. however, even though production of important components in the antiviral response to rsv infection (ifn-β, cxcl10, stat1, mxa and isg15) were reduced by treatment with 1,25(oh)2d, viral replication and viral load was not increased. thus, via increasing iκbα levels, 1,25(oh)2d is able to dampen the inflammatory response to rsv infection whilst maintaining the antiviral state and without having adverse effects on viral load, suggesting a potential role in reducing immunopathology. a similar study using alveolar a549 cells infected with rsv has also demonstrated that 1,25(oh)2d is able to decrease levels of phosphorylated stat-1 (pstat-1) and increase iκbα protein levels, with subsequent diminished expression of interferon regulatory factor 1 (irf1), irf7, ifn-β and cxcl8 mrna [188] . this study also used retroviral transduction to overexpress the common m4 vdr variant, or the m1 foki vdr variant, which has been associated with severe rsv bronchiolitis. no differences were observed between the two variants in viral replication, or the vitamin d-induced increase in iκbα and repression of nf-κb-regulated genes. however, in m1 foki vdr-expressing cells, vitamin d was not able to repress expression of the stat-1 regulated genes irf1 and irf7, due to decreased regulation of stat-1 phosphorylation. therefore, together these studies indicate that vitamin d is able to dampen nf-κb and stat-1 mediated inflammation to reduce rsv immunopathology, with an impairment in the regulation of stat-1 phosphorylation resulting in more severe disease. it has also been demonstrated that the antimicrobial peptides ll-37 and β-defensin 2 have anti-viral activity against rsv, blocking viral cellular entry, preventing virus-induced epithelial cell death, inhibiting production of new infectious particles and diminishing the spread of infection [56, 121] . since vitamin d has been demonstrated to be able to induce secretion of both of these molecules [116] [117] [118] , this provides a potential mechanism by which vitamin d may exert antiviral effects against rsv infection. finally, a number of studies have been carried out in calves, looking at the association between vitamin d and bovine rsv (brsv). naturally occurring brsv infection in young ruminants has been demonstrated to mimic the pathogenesis and lesions observed in rsv infection of infants, thus providing a useful model for studying rsv infection. conversely to the effects described above, whereby production of nf-κb-linked pro-inflammatory cytokines was inhibited, vitamin d treatment has been shown to elevate secretion of the pro-inflammatory cytokine il-12p40 following brsv infection [189] . no effect was observed on γδ t-cell cytokine production [190] , or ifn-γ, cxcl8, tnf-α, il-1β or il-6 secretion [189] . the influenza virus is associated with seasonal epidemics, severe pandemics, pneumonia and secondary bacterial infections. as such, a simple and cost-effective prevention strategy is desirable, with clinical trial results showing promising effects of vitamin d supplementation in the prevention of seasonal influenza a infection in japanese schoolchildren [17] . however, as with rsv and rhinovirus, in vitro work investigating the specific effects of vitamin d on the immune response to influenza viruses is lacking. in a study using alveolar a549 cells, the effect of pre-or post-treatment with 1,25(oh)2d on infection with influenza a h1n1 was assessed [191] . it was demonstrated that vitamin d had no effect on a549 cell viability following infection with influenza virus, viral clearance or the anti-viral state. whilst influenza infection increased the production of pro-inflammatory cytokines and chemokines, as with rsv infection [187, 188] , treatment with vitamin d either before or after influenza infection decreased gene expression of tnf-α, ifn-β, isg15, cxcl8, il-6 and rantes (ccl5). since an uncontrolled inflammatory response to influenza infection can cause complications such as pulmonary oedema, and the cytokine storm has been associated with more severe disease and higher mortality [192] ), this suppression of the hyper-inflammatory response may be beneficial in preventing immunopathology. the antimicrobial peptides ll-37 and human β-defensin 2 have also been shown to have anti-viral properties against influenza virus, reducing disease severity and viral replication, inhibiting infectivity, and demonstrating neutralising activity [54, 193] . as described above, since vitamin d has been shown to induce production of these amps, this may be another mechanism by which vitamin d is able to exert antiviral effects on influenza virus infection. finally, the majority of work into vitamin d and influenza infection has been investigating the potential use of vitamin d as an adjuvant in influenza vaccines. however, vitamin d has not been shown to be able to modulate the humoral response to inactivated influenza virus in this setting [194] [195] [196] [197] [198] . in the case of other common viral causes of ari in humans, no in vitro studies have been carried out to determine effects of vitamin d on the immune response to these pathogens. this is the case for human metapneumovirus, parainfluenza, adenovirus, coronaviruses, enterovirus and human bocavirus. this review has identified a modest number of laboratory studies investigating immunomodulatory effects of vitamin d metabolites in respiratory epithelial cells infected with respiratory viruses. despite clinical evidence that vitamin d supplementation may reduce susceptibility to such infections in vivo [28] , in vitro studies performed to date have not shown that vitamin d metabolites inhibit viral replication in epithelial cells. however, all the studies reviewed demonstrated effects of vitamin d metabolites on expression and secretion of pro-inflammatory cytokines and chemokines. interestingly, the effects of 1,25(oh)2d on chemokine expression and secretion varied between pathogens; this finding complements those of clinical trials suggesting that vitamin d-inducible responses may be more effective against some pathogens than others [17] . more studies are needed to characterize the in vitro actions of vitamin d in viral respiratory infection (particularly to investigate why suppression of type 1 interferon responses is not associated with increased viral replication), and to clarify the effects of vitamin d metabolites on respiratory virus-induced expression of cell surface markers mediating viral entry and bacterial adhesion to respiratory epithelial cells. the manuscript was conceived by both authors. clg wrote the draft manuscript which was subsequently edited by arm. the authors declare no conflict of interest. picornavirus, the most common respiratory virus causing infection among patients of all ages hospitalized with acute respiratory illness epidemiology of human respiratory viruses in children with acute respiratory tract infections in virological and clinical characterizations of respiratory infections in hospitalized children incidence of respiratory viruses in peruvian children with acute respiratory infections human bocavirus-infection (hbov): an important cause of severe viral obstructive bronchitis in children efficacy and effectiveness of influenza vaccines: a systemic review and meta-analysis antivirals for treatment of influenza: a systematic review and metaanalysis of observational 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immunity to respiratory viruses pattern recognition receptors tlr4 and cd14 mediate response to respiratory syncytial virus intracellular tlr4-md-2 in macrophages senses gram-negative bacteria and induces a unique set of lps-dependent genes murine toll-like receptor 2 activation induces type i interferon responses from endolysosomal compartments respiratory syncytial virus activates innate immunity through toll-like receptor 2 reis e sousa, c. rig-i-mediated antiviral responses to single-stranded rna bearing 5′-phosphates mda5 detects the double-stranded rna replicative form in picornavirus-infected cells activation of innate immune antiviral responses by nod2 distinct rig-i and mda5 signaling by rna viruses in innate immunity viral evasion and subversion of pattern-recognition receptor signalling signaling in innate immunity and inflammation neutrophil recruitment, chemokine receptors, and resistance to mucosal infection il-15 participates in the respiratory innate immune response to influenza virus infection cxcr2 is required for neutrophil recruitment to the lung during influenza virus infection, but is not essential for viral clearance cd11c+ antigen presenting cells from the alveolar space, lung parenchyma and spleen differ in their phenotype and capabilities to activate naive and antigen-primed t cells macrophage defences against respiratory tract infections cationic host defence peptides: potential as antiviral therapeutics antiviral activity and increased host defense against influenza infection elicited by the human cathelicidin ll-37 ll37 and cationic peptides enhance tlr3 signaling by viral double-stranded rnas the human cathelicidin ll-37 has antiviral activity against respiratory syncytial virus macrophage impairment underlies airway occlusion in primary respiratory syncytial virus bronchiolitis alveolar macrophages are essential for protection from respiratory failure and associated morbidity following influenza virus infection regulating the adaptive immune response to repiratory virus infection balancing immunity and tolerance cc chemokine ligand 3 (ccl3) regulates cd8(+)-t-cells effector function and migration following viral infection cc chemokine receptor 5 and cxc chemokine receptor 6 expression by lung cd8+ cells correlates with chronic obstructive pulmonary disease severity cxc chemokines ip-10 and mig expression and direct migration of pulmonary cd8+/cxcr3+ t cells in the lungs of patients with hiv infection and t-cell alveolitis orchestrating the orchestrators: chemokines in control of t cell traffic the role of the antibody response in influenza virus infection virus-neutralizing antibodies of immunoglobulin g (igg) but not of igm or iga isotypes can cure influenza virus pneumonia in scid mice antibody-dependent cellular cytotoxicity is associated with control of pandemic h1n1 influenza virus infection of macaques complement and viral pathogenesis influenza a virus m1 blocks the classical complement pathway through interacting with c1qa pharmacokinetics of vitamin d toxicity serum 25-hydroxyvitamin d is a reliable indicator of vitamin d status vitamin d supplementation, 25-hydroxyvitamin d concentrations, and safety steroid-hormone rapid actions, membrane receptors and a conformational ensemble model the vitamin d receptor is present in caveolae-enriched plamsa membranes and binds 1 alpha,25(oh)2-vitamin d3 in vivo and in vitro vitamin d receptor: new assignments for an already busy receptor the yin and yang of vitamin d receptor (vdr) signaling in neoplastic progression: operational networks and tissue-specific growth control manolagas, s. 1,25-dihydroxyvitamin d3 receptors in human leukocytes human t lymphocytes are direct targets of 1,25-dihydroxyvitamin d3 in the immune system differential regulation of vitamin d receptor and its ligand in human monocyte-derived dendritic cells modulatory effects of 1,25-dihydroxyvitamin d3 on human b cell differentiation dcs metabolize sunlight-induced vitamin d3 to 'program' t cell attraction to the epidermal chemokine ccl27 does vitamin d affect risk of developing autoimmune disease?: a systematic review the role of vitamin d in cancer prevention and treatment vitamin d deficiency and risk of cardiovascular disease association between serum 25-hydroxyvitamin d level and upper respiratory tract infection in the third national health and nutrition examination survey regulated production and intracrine action of 1,25-dihydroxyvitamin d3 in the chick myelomonocytic cell line hd-11 regulation of 1,25-dihydroxyvitamin d3 production by cultured alveolar macrophages from normal human donors and from patients with pulmonary sarcoidosis regulation of 1 alpha, 25-dihydroxyvitamin d3 synthesis in macrophages from arthritic joints by phorbol ester, dibutyryl-camp and calcium ionophore (a23187) alternative splicing of vitamin d-24-hydroxylase: a novel mechanism for the regulation of extrarenal 1,25-dihydroxyvitamin d synthesis vitamin d signaling, infectious diseases, and regulation of innate immunity regulation of intracrine production of 1,25-dihydroxyvitamin d and its role in innate immune defense against infection toll-like receptor 8 ligands activate a vitamin d mediated autophagic response that inhibits human immunodeficiency virus type 1 increased expression of 25-hydroxyvitamin d-1alpha-hydroxylase in dysgerminomas: a novel form of humoral hypercalcemia of malignancy immune regulation of 25-hydroxyvitamin-d3-1alpha-hydroxylase in human monocytes regulation of 25-hydroxyvitamin d3-1 alpha-hydroxylase and production of 1 alpha,25-dihydroxyvitamin d3 by human dendritic cells tlr-induced local metabolism of vitamin d3 plays an important role in the diversification of adaptive immune responses tlr ligands that stimulate the metabolism of vitamin d3 in activated murine dendritic cells can function as effective mucosal adjuvants to subcutaneously administered vaccines respiratory epithelial cells convert inactive vitamin d to its active form: potential effects on host defense modlin, r. il-15 links tlr2/1-induced macrophage differentiaition to the vitamin d-dependent antimicrobial pathway interleukin 13 exposure enhances vitamin d-mediated expression of the human cathelicidin antimicrobial peptide 18/ll-37 in bronchial epithelial cells immune regulation of 25-hydroxyvitamin d-1 alpha-hydroxylase in human monocytic thp1 cells: mechanisms of interferon-gamma-mediated induction t-cell cytokines differentially control human monocyte antimicrobial responses by regulating vitamin d metabolism monocyte 1 alpha-hydroxylase regulation: induction by inflammatory cytokines and suppression by dexamethasone and uremia toxin new analogs of vitamin d3 the multiple faces of caveolae identification of 25-hydroxyvitamin d3 1alpha-hydroxylase gene expression in macrophages human cathelicidin, hcap-18, is processed to the antimicrobial peptide ll-37 by extracellular cleavage with proteinase 3 the human antimicrobial and chemotactic peptides ll-37 and alpha-defensins are expressed by specific lymphocyte and monocyte populations the peptide antibiotic ll-37/hcap-18 is expressed in epithelia of the human lung where it has broad antimicrobial activity at the airway surface ll-37, the neutrophil granule-and epithelial cell-derived cathelicidin, utilizes formyl peptide receptor-like 1 (fprl1) as a receptor to chemoattract human peripheral blood neutrophils, monocytes, and t cells human cathelicidin ll-37 is a chemoattractant for eosinophils and neutrophils that acts via formyl-peptide receptors the human antimicrobial peptide ll-37 is a multifunctional modulator of innate immune responses an antimicrobial cathelicidin peptide, human cap18/ll-37, suppresses neutrophil apoptosis via the activation of formyl-peptide receptor-like 1 and p2x7 the cationic antimicrobial peptide ll-37 modulates dendritic cell differentiation and dendritic cell-induced t cell polarization cationic host defence peptides: multifaceted role in immune modulation and inflammation cutting edge: 1,25-dihydroxyvitamin d3 is a direct inducer of antimicrobial peptide gene expression human cathelicidin antimicrobial peptide (camp) gene is a direct target of the vitamin d receptor and is strongly up-regulated in myeloid cells by 1,25-dihydroxyvitamin d3 induction of cathelicidin in normal and cf bronchial epithelial cells by 1,25-dihydroxyvitamin d(3) vitamin d induces the antimicrobial protein hcap18 in human skin defensins: antimicrobial peptides of innate immunity role of human beta-defensin-2 during tumor necrosis factor-alpha/nf-kappab-mediated innate antiviral response against human respiratory syncytial virus differentiation of a human monocytic cell line by 1,25-dihydroxyvitamin d3 (calcitriol): a morphologic, phenotypic, and functional analysis 25-dihydroxyvitamin d3 exerts opposing effects to il-4 on mhc class-ii antigen expression, accessory activity, and phagocytosis of human monocytes vitamin d, vitamin d receptor, and macroautophagy in inflammation and infection reiner, n. 1alpha,25-dihydroxyvitamin d3-induced monocyte antimycobacterial activity is regulated by phosphatidylinositol 3-kinase and mediated by the nadph-dependent phagocyte oxidase reactive oxygen species induce antiviral innate immune response through ifn-λ regulation in human nasal epithelial cells mucosal reactive oxygen species are required for antiviral response: role of duox in influenza a virus infection requirement of nox2 and reactive oxygen species for efficient rig-i-mediated antiviral response through regulation of mavs expression il-15 induces ifn-beta and inos gene expression, and antiviral activity of murine macrophage raw 264.7 cells regulation of the expression of inducible nitric oxide synthase influenza a virus induction of oxidative stress and mmp-9 is associated with severe lung pathology in a mouse model downregulation of inducible nitric oxide synthase (inos) expression is implicated in the antiviral activity of acetylsalicylic acid in hcv-expressing cells 1,25-dihydroxyvitamin d3 induces nitric oxide synthase and suppresses growth of mycobacterium tuberculosis in a human macrophage-like cell line protective role of 1 alpha, 25-dihydroxyvitamin d3 against oxidative stress in nonmalignant human prostate epithelial cells 1-alpha,25-dihydroxyvitamin d3 regulates inducible nitric oxide synthase messenger rna expression and nitric oxide release in macrophage-like raw 264.7 cells vitamin d: oxidative stress, immunity, and aging autophagy in antiviral innate immunity vitamin d3 induces autophagy in human monocytes/macrophages via cathelicidin autophagy as a basis for the health-promoting effects of vitamin d vitamin d3 down-regulates monocyte tlr expression and triggers hyporesponsiveness to pathogen-associated molecular patterns binding of lipopeptide to cd14 induces physical proximity of cd14, tlr2 and tlr1 functional antagonism between vitamin d3 and retinoic acid in the regulation of cd14 and cd23 expression during monocytic differentiation of u-937 cells regulation of cd14 expression during monocytic differentiation induced with 1 alpha,25-dihydroxyvitamin d3 injury enhances tlr2 function and antimicrobial peptide expression through a vitamin d-dependent mechanism direct and indirect induction by 1,25-dihydroxyvitamin d3 of the nod2/card15-defensin beta2 innate immune pathway defective in crohn disease 1 alpha,25-dihydroxyvitamin d3 inhibits differentiation, maturation, activation, and survival of dendritic cells leading to impaired alloreactive t cell activation 1,25-dihydroxyvitamin d(3) inhibits dendritic cell differentiation and maturation in vitro the vitamin d3 analog calcipotriol suppresses the number and antigen-presenting function of langerhans cells in normal human skin suppressive effect of 1alpha,25-dihydroxyvitamin d3 on type i ifn-mediated monocyte differentiation into dendritic cells: impairment of functional activities and chemotaxis vitamin d3 and the immune system: maintaining the balance in health and disease panina-bordignon, p. inhibition of il-12 production by 1,25-dihydroxyvitamin d3. involvement of nf-kappab downregulation in transcriptional repression of the p40 gene ) dose-dependently inhibits lps-induced cytokines production in pbmc modulating intracellular calcium redirection of human autoreactive t-cells upon interaction with dendritic cells modulated by tx527, an analog of 1 immunosuppressive actions of 1,25-dihydroxyvitamin d3: preferential inhibition of th1 functions reversing the defective induction of il-10-secreting regulatory t cells in glucocorticoid-resistant asthma patients interleukin-10 regulation in normal subjects and patients with asthma calcitriol suppresses antiretinal autoimmunity through inhibitory effects on the th17 effector response immune modulatory treatment of trinitrobenzene sulfonic acid colitis with calcitriol is associated with a change of a t helper th17 to a th2 and regulatory t cell profile interleukin-17 and type 17 helper t cells deficiency of th17 cells in hyper ige syndrome due to mutations in stat3 in vitro generation of interleukin 10-producing regulatory cd4(+) t cells is induced by immunosuppressive drugs and inhibited by t helper type 1 (th1)-and th2-inducing cytokines 1,25-dihydroxyvitamin d3 and il-2 combine to inhibit t cell production of inflammatory cytokines and promote development of regulatory t cells expressing ctla-4 and foxp3 regulation of lymphokine production and human t lymphocyte activation by 1,25-dihydroxyvitamin d3. specific inhibition at the level of messenger rna vitamin d3: a transcriptional modulator of the interferon-gamma gene 25-dihydroxyvitamin d3 has a direct effect on naive cd4(+) t cells to enhance the development of th2 cells regulatory b cells in autoimmune diseases restoration of regulatory and effector t cell balance and b cell homeostasis in systemic lupus erythematosus patients through vitamin d supplementation vitamin d, invariant natural killer t-cells and experimental autoimmune disease vitamin d has a direct immunomodulatory effect on cd8+ t cells of patients with early multiple sclerosis and healthy control subjects the anti-inflammatory effects of 1,25-dihydroxyvitamin d3 on th2 cells in vivo are due in part to the control of integrin-mediated t lymphocyte homing issazadeh-navikas, s. dual effects of vitamin d-induced alteration of th1/th2 cytokine expression: enhancing ige production and decreasing airway eosinophilia in murine allergic airway disease 1,25-dihydroxyvitamin d3 inhibits ifn-gamma and il-4 levels in vitro polaization of primary murine cd4+ t cells vitamin d3 attenuates th2 responses to aspergillus fumigatus mounted by cd4+ t cells from cystic fibrosis patients with allergic bronchopulmonary aspergillosis availability of 25-hydroxyvitamin d(3) to apcs controls the balance between regulatory and inflammatory t cell responses frequency and natural history of rhinovirus infections in adults during autumn the common cold studies of the community and family: acute respiratory illness and infection effects of vitamin d on airway epithelial cell morphology and rhinovirus replication respiratory syncytial virus: current and emerging treatment options respiratory syncytial virus--a comprehensive review severe respiratory syncytial virus bronchiolitis in infancy and asthma and allergy at age 13 cord blood vitamin d deficiency is associated with respiratory syncytial virus bronchiolitis genetic predisposition of rsv infection-related respiratory morbidity in preterm infants vitamin d receptor (vdr) polymorphisms and severe rsv bronchiolitis: a systematic review and meta-analysis confirmation of an association between single nucleotide polymorphisms in the vdr gene with respiratory syncytial virus related disease in south african children vitamin d-binding protein haplotype is associated with hospitalization for rsv bronchiolitis vitamin d decreases respiratory syncytial virus induction of nf-kappab-linked chemokines and cytokines in airway epithelium while maintaining the antiviral state defective control of vitamin d receptor-mediated epithelial stat1 signaling predisposes to severe respiratory syncytial virus bronchiolitis differential expression of cytokines in response to respiratory syncytial virus infection of calves with high or low circulating 25-hydroxyvitamin d3 differential chemokine and cytokine production by neonatal bovine γδ t-cell subsets in response to viral toll-like receptor agonists and in vivo respiratory syncytial virus infection calcitriol [1, 25[oh]2 d3] pre-and post-treatment suppresses inflammatory response to influenza a (h1n1) infection in human lung a549 epithelial cells th1 and th17 hypercytokinemia as early host response signature in severe pandemic influenza interactions of alpha-, beta-, and theta-defensins with influenza a virus and surfactant protein d calcitriol (1,25-dihydroxy-vitamin d3) coadministered with influenza vaccine does not enhance humoral immunity in human volunteers vitamin d is not associated with serologic response to influenza vaccine in adults over 50 years old impact of vitamin d administration on immunogenicity of trivalent inactivated influenza vaccine in previously unvaccinated children vitamin d supplementation does not increase immunogenicity of seasonal influenza vaccine in hiv-infected adults serum 25-hydroxyvitamin d level and influenza vaccine immunogenicity in children and adolescents key: cord-325436-pp3q022y authors: alkhatib, ahmad title: antiviral functional foods and exercise lifestyle prevention of coronavirus date: 2020-08-28 journal: nutrients doi: 10.3390/nu12092633 sha: doc_id: 325436 cord_uid: pp3q022y novel coronavirus (covid-19) is causing global mortality and lockdown burdens. a compromised immune system is a known risk factor for all viral influenza infections. functional foods optimize the immune system capacity to prevent and control pathogenic viral infections, while physical activity augments such protective benefits. exercise enhances innate and adaptive immune systems through acute, transient, and long-term adaptations to physical activity in a dose-response relationship. functional foods prevention of non-communicable disease can be translated into protecting against respiratory viral infections and covid-19. functional foods and nutraceuticals within popular diets contain immune-boosting nutraceuticals, polyphenols, terpenoids, flavonoids, alkaloids, sterols, pigments, unsaturated fatty-acids, micronutrient vitamins and minerals, including vitamin a, b6, b12, c, d, e, and folate, and trace elements, including zinc, iron, selenium, magnesium, and copper. foods with antiviral properties include fruits, vegetables, fermented foods and probiotics, olive oil, fish, nuts and seeds, herbs, roots, fungi, amino acids, peptides, and cyclotides. regular moderate exercise may contribute to reduce viral risk and enhance sleep quality during quarantine, in combination with appropriate dietary habits and functional foods. lifestyle and appropriate nutrition with functional compounds may offer further antiviral approaches for public health. viral infections are responsible for significant global morbidity and mortality rates across the world, and viral outbreaks such as novel coronavirus (covid-19) [1] . reports from the world health organization (who) estimate 3-5 million hospitalized cases of seasonal influenza severe illness, resulting in 290,000-650,000 annual deaths [2] . currently, covid-19 is causing a health crisis across the world. limiting the spread of infections in the short and medium terms involves a number of preventative public health practices including regular hand washing, covering coughs, lockdown, and social distancing measures. vaccines have been implemented for preventing and controlling several viruses over the past century and have also been used for preventing common influenza [3, 4] . however, influenza vaccine development takes a significant amount of time [5] , which necessitates alternative complementary remedies for covid-19. furthermore, antiviral medication treatments face continuous challenges in terms of drug dose and selection and intervention phase, especially during acute respiratory infections [6] . lifestyle approaches could play an essential antiviral long-term preventative role. the antiviral role of nutrition and exercise as the two lifestyle prevention pillars has received little research attention. in particular, how the antiviral immunological defence capacity could be enhanced using functional foods, nutraceuticals, and physical activity behaviors, whether such behaviors are alone or combined. functional foods and nutraceuticals can be safe and cost-effective strategies to enhance the immune system and provide protection from pathogenic viral infections. for example, optimal intake of selected micronutrients has been highlighted in controlling the impact of virulent strain infections, including lower and upper respiratory tract infections, through optimizing a well-functioning immune system [7] . on the other hand, the role of physical activity and exercise in enhancing the immune system is well established [8] . nutrition and lifestyle modifications may not be definitive measures to absolutely prevent persons from contracting covid-19 when exposed. however, they could help as an adjuvant therapy to reduce the risk through enhanced immunity. this review presents key evidence on how functional foods and lifestyle approaches, including physical activity, effective for cardiometabolic disease prevention outcomes [9] , can also optimize the immune system response to viral infection, especially respiratory tract infections and covid-19. the review also makes specific and practical evidence-based recommendations for the use of antiviral functional foods and lifestyle approaches. in terms of physical activity prevention of chronic disease morbidity and mortality risks, a dose response relationship is well established for non-communicable disease (ncd) prevention [10] . exercise induces cardiovascular, respiratory, and metabolic adaptations, which result in higher maximal oxygen uptake ( . v o 2max ), carbon dioxide production, minute ventilation, breathing frequency, stroke volume, and cardiac output [11] . improvement in whole-body cardiometabolic and respiratory functions boosts the immune system defence through several acute and long-term mechanisms, which have been well highlighted recently [12, 13] . however, less is reported about how such exercise-dependent mechanisms protect against communicable diseases (cds), especially viral infections such as influenza and the recent covid-19 outbreak. exercise impacts all immune cells within both innate and adaptive immune systems, particularly elevating the activity of natural killer (nk) cells, neutrophils, and macrophages following moderate exercise (less than 60% of . v o 2max ) [8] . for example, acute aerobic exercise (running, cycling) have been shown to increase monocyte number [14] . monocytes play an integral antiviral role, and it has been shown that in a variety of influenza a viruses (including the circulating swine-origin virus, similar to covid-type viruses), exercise induces monocytes to differentiate within 18 hours into cd16(-)cd83(+) mature dendritic cells with enhanced capacity to activate t-cells [15] . long-term moderate exercise training increases the expression of t-helper (th) cells and associated th balances [16] . enhanced t-cell proliferation was particularly found following prolonged moderate exercise training in high-risk populations such as postmenopausal women cancer survivors and the very old. an increase in t-cell proliferation (by 218 per dpm × 106 cells) has been found in post-menopausal breast cancer survivors who exercised for 15-30 min for 15 weeks at 50% and 70% of . v o 2max [17] , while increased cd4+ t-cells were also found in older adults aged 80 years, walking 30 km per day [18] . those high-risk groups have been found to be particularly vulnerable to viral infections and more serious symptoms as reflected by recent governmental advice regarding covid-19 [19, 20] . exploring the exercise role in protecting and controlling covid-19 and other novel viral infections is essential. severe exercise intensity, whether acute or chronic, can be counter-productive in terms of the susceptibility to infections, since it is linked with higher upper respiratory tract infection rates among elite endurance athletes [21, 22] . mucosal immunology antibodies such as salivary immunoglobulin a (iga), and immunoglobin m (igm) concentrations have been shown to decline immediately after a bout of intense exercise in elite swimmers, but usually recover within 24 h [22] . however, modulating the intensity and duration of exercise can optimize the immune system response outcomes acutely and chronically [8, 23] . higher exercise intensities (above 70% . v o 2max ) and supramaximal exercise (100% or above) induce a transient oxidative stress and muscle damage response of oxidative stress, cell integrity, and homeostasis biomarkers, especially during the first 24 hour post exercise [24, 25] . both young and older adults have shown an increase in recombinant interleukin-2 (ril-2) stimulation of nk cells immediately (15 min) following an acute intense bout of maximal cycling exercise [26] . when followed for 12 days, it was found that neutrophil mobilization was concurrent with enzyme efflux, particularly those related to cell damage such as creatine kinase (ck) and antioxidative capacity such as superoxide dismutase (sod) [27] . acute repeated exercise bouts have also been implicated in the removal and regeneration of aged immune cells, especially cell senescent naïve, memory cd4+ and cd8+ t-lymphocytes, and an elevated apoptotic lymphocyte in peripheral blood [28] . the immunological transient response includes a temporal stress (e.g., disturbance of cell homeostasis and oxidative stress) induced by an acute exercise challenge, and may play a role in long-term enhanced immune system, especially when exercise is repeated chronically (i.e., exercise training). these entropic exercise-induced effects on the immune system may act as a natural vaccine against viral infections such as covid-19. in fact, eccentric exercise has already been demonstrated to act as an adjuvant to influenza vaccination in humans [29] . the trial randomized 60 healthy men and women who performed upper body eccentric exercise (deltoid and biceps brachii muscles) 6 hours prior to receiving influenza vaccination, and were monitored for antibody titers up to 20 weeks. the results showed that interferon-gamma responses were enhanced by exercise in men, whereas antibody titres were enhanced in women, which were concurrent with improved arm circumference (i.e., physical outcome benefit). the interferon-gamma response was positively associated with the percentage increase in arm circumference. the study suggested that eccentric exercise of the muscle at the site of vaccine administration could act as a behavioral adjuvant to vaccination. therefore, exercise immunological benefits alone or as an adjuvant antiviral treatment should be further investigated for preventing and controlling covid-19. the immune function response to exercise is influenced by several factors including nutritional status, body weight, hygiene, and mental health. the immune function is known to be superior in highly conditioned versus sedentary individuals. sedentary lifestyle and insufficient physical activity levels induce several physiological impairments, which reflect reduced cardiovascular and respiratory capacity, obesity, and associated cardiometabolic chronic diseases [30, 31] . consequences of sedentary lifestyle and physical inactivity include a compromised immune system due to manifestation of systemic inflammation, oxidative stress, and associated immunosuppressive mechanisms [10, 31] . prevalence of sedentary behavior and low physical activity levels have been reported in those with obesity, diabetes, and underlying insulin resistance and oxidative stress, and have been linked with increased susceptibility to contracting viral infections, including pandemic influenzas such as h1n1 and covid-19 [32] . conversely, higher physical activity and fitness levels in adults are associated with an optimized immunity indicated by reduced white blood cell count, c-reactive protein (crp), interleukins (il-6, and il-18), tumor necrosis factor alpha (tnf-α), and other inflammatory biomarkers [33] . therefore, any physical activity or exercise dose is considered beneficial compared to being sedentary, especially during and after covid-19-related lockdown, social distancing, or quarantine measures introduced in several countries. moderate exercise intensity is recommended, especially during and after a social distancing lockdown, which requires an avoidance of severe intensities. a practical method of achieving moderate exercise intensity is using 40-70% of maximum heart rate (hr max = 220-age). exercising at home, especially to perform resistance type activities using own body weight, and to interrupt sedentary behavior by reducing sitting times are particularly recommended for older and high-risk individuals with chronic conditions such as diabetes [31, 34] . exercise at home is also suited for the avoidance of the airborne coronavirus, especially during quarantine, and may include strengthening, balance and control, stretching, or a combination of these (walking, lifting and carrying, lunges, stair climbing, stand-to-sit and sit-to-stand using house items, squats, sit-ups, yoga) [35] . a volume increase in weekly exercise is recommended under the covid-19 quarantine from 150 min to 200-400 min aerobic exercise distributed across 5-7 days, with at least 2-3 resistance sessions, to compensate for the decreased mobility during lockdown [36] . this results in achieving an increase in . v o 2max as a practical aim. enhanced . v o 2max is particularly important for those who are considered at high-risk of covid-19 such as those who are overweight or those with obesity, insulin resistance, and diabetes, who typically have chronic low-grade inflammation characterized by increased levels of several pro-inflammatory cytokines and the inflammasome, and who are predisposed to greater risks for infection along with more adverse outcomes [37] . it is recommended that exercise is performed as part of a multicomponent personalized lifestyle approach (personalized nutrition, exercise intensities, technology, behavior, mental wellbeing) especially for high-risk individuals such as those with diabetes [38] . functional foods naturally possess active ingredients or "nutraceuticals" that are associated with disease preventative health benefits are now widely accepted for the prevention and management of major ncds, especially those characterized by inflammatory and oxidative stress disorders such as diabetes and cardiovascular disease [9, 39] . however, less is known about the role of functional foods in communicable diseases (cds), especially on the immune system defence against viral infections such as covid-19. a variety of fruits, vegetables, oily fish, olive oil, nuts, legumes are all considered functional foods based on their natural contents of nutraceuticals, including polyphenols, terpenoids, flavonoids, alkaloids, sterols, pigments, and unsaturated fatty acids [9, 40] . polyphenol-rich herbs, especially coffee, differently fermented teas (green, black)and yerba maté, have also shown to have various effectiveness on metabolic and microvascular activities, cholesterol and fasting glucose lowering, anti-inflammation and anti-oxidation in high-risk populations [9, 41] . bioactive peptides, naturally present in food proteins or formulated as nutraceuticals based on their molecular weight, amino acid chain length, or peptide composition, have also been postulated to elicit versatile physiological responses associated with immunological, antimicrobial, cardiovascular, gastrointestinal, neurological, and other hormonal activities of the human system [42] . such functional food benefits can be translated to protect against viral infections and covid-19. viral infections are characterized by a compromised immune function and deficient micronutrient stores, particularly vitamins, including vitamins a, b6, b12, c, d, e, and folate, and trace elements, including zinc, iron, selenium, magnesium, and copper [7] . evidence already supports an efficient function of the immune system through consuming those various nutraceuticals within a variety of functional foods including essential fatty acids, linoleic acids, essential amino acids, and the aforementioned vitamins and minerals, especially where forms of immunity may be affected by deficiencies in one or more of these nutraceuticals [43, 44] . adequate dietary intake, and supplementation of such functional foods, contribute to maintaining optimal levels in the human body, which enhances several aspects of the immune system [7, 45] , and provides an important antiviral prevention of covid-19 [46] . conversely, less robust immune responses have been shown to be the primary risk factor for covid-19 [47] , which makes it timely to describe the protective role of functional food component benefits in the context of preventing covid-19 and seasonal infections. in terms of jointly addressing ncd and cd prevention within high-risk populations, investigating the functional foods effects on cds including covid-19 is particularly important. higher infection and mortality rates related to covid-19 have been documented among older adults and patients with obesity, cardiac diseases, hypertension, or diabetes [48] . for example, covid-19 statistics in england showed that almost a third (31.3%) of covid-19-related mortalities had type-2 diabetes [49] , while there was a two-fold increase (86%) in requiring mechanical ventilation among covid-19 infected obese individuals compared with (47%) of infected healthy weight individuals [50] . the prevalence of ncds, especially diabetes amongst high-risk groups, is becoming a matter of emerging importance, and diabetes is now considered a risk factor for the progression and prognosis of covid-19 [51, 52] . therefore, optimal "immune-enhancing" functional foods combined with behavioral lifestyle approaches (especially exercise) could provide an optimal prevention of the double burdens of ncd and cd multimorbidity. various dietary patterns contain functional food components that have been promoted in the past for ncd prevention, especially the vegetarian diet, the nordic diet, or the mediterranean diet (md), and its combination with other lifestyle approaches [9, 39, 53, 54] . common functional foods within those diets include plant-based fruit and vegetables such as olive oil and tree nuts, seeds, fish, dairy products, and herbs, teas, and fermented products, which contain key nutraceuticals with disease protective anti-inflammatory and anti-oxidation properties [9, 54, 55] . established health protective functional components include monounsaturated fatty acids (mufa) such as oleic acid in olive oil, omega-3 polyunsaturated fatty acids (e.g., alpha-linolenic acid) found in tree nuts such as walnuts, eicosapentaenoic acid (epa), and docosahexaenoic acid (dha) found in oily fish, high amounts of polyphenol flavonoids and antioxidants found in fruit and vegetables, and high amounts of fiber found mainly in cereal and whole-grain foods [54] . consuming those functional foods, and their components vary across geographical global regions [9, 41, 54, [56] [57] [58] , but what is agreed on is their cardiometabolic protective benefits of reducing major ncds and mortality risks [9, 53, 59] . the challenge is to translate such functional effects towards enhancing and protecting the immune system and its antiviral defence response into the prevention of emerging cds such as covid-19. enhancing the antiviral immune defence can benefit from the functional food intake of a considerable variety of plant, animal, and fungi species, consumed across different diets and cultural practices including traditional herbal medicine such as teas, roots, mushrooms, and fermented plants and leaves; md components such as olive-based products, oily fish, seeds, fruits, and vegetables; popular beverages such as coffee; and protein-rich foods such as chicken extract and soybean peptides. the majority of such foods contain naturally occurring vitamins and minerals (e.g., vitamins c, d, b 6 , b 12 , a, e, and minerals of zinc, copper, iron, and selenium), and other phenolic compounds that are immunoprotective particularly through antioxidation and anti-inflammation properties [41, 43] . other foods such as oily fish omega-3 fatty acids contain monounsaturated fatty acids such as omega-3 fatty acids (epa and dha) in oily fish, which can be enzymatically converted to specialized pro-resolving mediators (spms) known as resolvins, protectins, and maresins, which are molecules that support inflammatory resolution and healing of infected sites including the respiratory tract, which could prevent acute lung injury [7] . fermented food products (e.g., yoghurt, pickles, fermented fruits, vegetables, plant, and drinks) contain probiotics, and have also been shown to enhance gut bacteria profile and gut-lung axis-related respiratory fitness [60, 61] . a summary of systematic reviews and randomized controlled trials reported reduced incidence and severity of upper and lower respiratory tract infections (odds ratio ∼ 0.8-0.5) by using different probiotics, especially lactobacilli and bifidobacteria [61] . the efficacy of probiotics in reducing covid-19 infected patients has not yet been established, but the prophylactic benefits for enhancing the immune system are supportive of their long term use [60] , especially considering that improving gut microbiota profile has been recently implicated in preventing covid-19 in older and high-risk individuals with compromised immune systems [62] . selected food supplements and micronutrient vitamins and trace elements have been reviewed elsewhere in terms of optimizing the immune responses [7, 63, 64] . other reviews have highlighted the importance of key vitamins (e.g., vitamin d) for regulating sleep patterns during quarantine or lockdown measures [65] [66] [67] . given the promising role of popular functional foods, such as those within the md including olive oil, and asian and african herbal teas and fermented foods and popular beverages as part of lifestyle disease prevention [11, 40] , it is important to contextualize the antiviral mechanisms of such functional foods. below is a review of popular foods within various dietary patterns, including olive oil nutraceuticals, popular vitamins such as vitamin d, traditional medicinal herbs and roots, and protein peptides for preventing viral infections including covid-19, especially when they are adopted as part of an active lifestyle. olive oil (oo), and its constituents (leaves and bark), form an important immune-enhancing functional food due to the significant ncd preventative benefits, especially of cardiovascular disease, diabetes, and cancer, which have been reviewed elsewhere [40, 68] . oo, especially extra-virgin oo (evoo) contains monounsaturated fatty acids, and several polyphenols including oleuropein and hydroxytyrosol, which have several antioxidative and anti-inflammatory properties, which can be linked with significant antiviral and antibacterial potential. oleuropein has shown a potential antiviral activity against respiratory syncytial virus (rsv), a common upper respiratory infection (uri) virus [69] . this effect has been attributed to the antioxidative property of elenolic acid as a main fragment in oleuropein, which has long been shown to have potent antiviral activities against herpes, influenza a and b, and parainfluenza 1, 2, and 3 viruses [70] . antioxidant capacity of oo was later shown to be independent of the size of the antiviral effect, with oleuropein showing superior antiviral effects compared with other secoiridoid glucosides isolated from ligustrum lucidum [69] . however, antioxidant properties can vary among oo phenolics. a more recent study by paiva-martins et al. (2010) [71] compared the capacity of four important oo phenolic compounds, oleuropein, hydroxytyrosol, and the oleuropein aglycones 3,4-dihydroxyphenylethanol-elenolic acid (3,4-dhpea-ea) and 3,4-ihydroxyphenylethanol-elenolic acid dialdehyde (3,4-dhpea-eda) for their protection of red blood cells (rbcs) from oxidative haemolysis induced by the physiological initiator h2o2. the study tested the amount of haemolysis by spectrophotometry, and the compounds were also tested in the presence and absence of the naturally occurring antioxidant ascorbic acid. all compounds were revealed to significantly protect rbcs from oxidative haemolysis induced by h2o2 at 40 and 80 µm, with the order of activity being 3,4-dhpea-eda>3,4-dhpea-ea>hydroxytyrosol=oleuropein. however, at 20, 10, and 5 µm, only 3,4-dhpea-eda showed a significant protection against the oxidative injury, suggesting that 3,4-dhpea-eda plays an important protective role against reactive oxygen species-induced oxidative injury in rbcs, and this effect is more potent than the one evidenced by hydroxytyrosol or oleuropein. the antioxidation protective benefits of oo, especially evoo, which has a higher phenolic content [40] promotes its role for enhancing the immune system defence against viruses. hydroxytyrosol antiviral mechanisms were showed through its inactivation effects on influenza a viruses, especially during the virus morphological changes, such as the presence of a viral envelope which is an integral membrane protein involved in several aspects of the virus life cycle including its assembly, budding, and pathogenesis [72] . the mechanisms of which oo nutraceuticals protect against viral infections have often focused on the hydroxytyrosol preventative effects on hiv from entering the host cell and binding the catalytic site of the hiv-1, and its inhibitory effect on both viral entry and integration [73] . regular intake of olive leaf extracts, rich in polyphenol flavonoids, have been shown to be responsible for a 33% reduction in uri [74] . such promising antiviral potential was attributed to the following antioxidation actions of oleuropein with dose-dependent inhibition of the copper sulphate-induced oxidation of low-density lipoproteins (ldls), and induced increase in nitric oxide production in macrophages and functional activity. in another study among high-school athletes who were prone to uri, olive leaf extract supplementation (20 g, containing 100 mg oleuropein) was shown to reduce the duration of infection (28% reduction in sick days) but not the incidence rate [75] . thus, olive polyphenols (both in oo and leaf), especially oleuropein and hydroxytyrosol, seem to promote antiviral defence and can be an adjacent prevention to control uris. exploring oo mechanisms for protecting against novel viruses such as covid-19, especially its protein viral envelop function and interaction with host cells would also be important. the benefits of oo intake, especially as part of a balanced diet such as the md can be further augmented via physical activity, especially strength and resistance type exercise [40] . such an approach is likely to be an effective prevention of viral infections. in terms of the recommended oo dose, a moderate dose of 20-30 g/day (especially polyphenol-rich evoo) in combination with other dietary functional foods can be recommended for enhancing the immune system, which is in line with recent ncd prevention recommendations [68] . the role of vitamin d in ameliorating the effects of both ncds and cds is now well accepted. vitamin d reduces acute respiratory tract infection, and its deficiency is linked with susceptibility to viral infections, and also with various cancers, diabetes, and cvd [64, 66] . research into the role of vitamin d in preventing covid-19 and influenza viral infections has gained recent momentum through various reviews and meta-analyses, especially given that individuals who are susceptible to covid-19 infections are mainly high-risk individuals with various ncds such as diabetes and cvd, suggesting that vitamin d could be the missing link between ncds and viral cds [46, 66] . based on the latter [66] , several mechanisms of how adequate vitamin d availability can reduce the risk of viral infections and covid-19 through the following mechanisms: (a) lowering viral replication rates through cathelicidins and defensins, and preventing lung injures that lead to pneumonia through its anti-inflammatory cytokines; (b) potential for vitamin d supplementation effectiveness in reducing the risk of influenza especially in deficient individuals; (c) documented reduced risk of covid-19 during the summer indicated by a lower number of cases in the southern hemisphere, compared with higher number of cases in the winter months when 25-hydroxyvitamin d (25(oh)d) concentrations are lowest; (d) vitamin d deficiency has been found to contribute to acute respiratory distress syndrome; and that case-fatality rates increase with age and with chronic disease comorbidity, both of which are associated with lower 25(oh)d concentration. sleep disorders during covid-19 quarantine could also be ameliorated through maintaining adequate vitamin d levels within the body. this could mainly be done through sun exposure [76] , and to a smaller extent from dietary intake or supplementation [77] . vitamin d plays an important role in regulating sleep patterns, circadian rhythm, enhancing sleep quality, and indirectly ameliorating sleep apnea [78] . for example, vitamin d receptors and the enzymes that control its activation and degradation have been found in brain regions involved in sleep regulation; and vitamin d is also involved in melatonine production pathways, and can affect restless legs syndrome and obstructive sleep apnea syndrome [67] . the best source of vitamin d is sunshine exposure, but it is abundant in several foods including oily fish, tuna, dairy, and egg yolk. grant et al. (2020) [46] recommended supplementation in individuals with highest risk of covid-19 infection or vitamin d deficiency (10,000 iu/d of vitamin d3) to raise 25(oh)d concentrations above 40-60 ng/ml (100-150 nmol/l). for treatment of people who become infected with covid-19, higher vitamin d3 doses are recommended. traditional antiviral medicinal therapies across different cultures are essentially based on a combination of several functional foods and nutraceuticals with active immunomodulators, polyphenols, anti-inflammatory, and anti-oxidation components. armeniacae semen (apricot seeds), cinnamomi cortex (chinese cinnamon), glycyrrhizae radix (liquorice root), and ephedrae herba form a japanese traditional medicine called "maoto", which is often administered orally as granules to adults with seasonal influenza [79] . it has been shown to be well tolerated and associated with equivalent clinical and virological efficacy to neuraminidase inhibitors in helping progeny influenza viruses to leave without re-infecting the host cell [80] . licorice roots which contain the active component glycyrrhizin, have been shown to inhibit influenza a virus uptake into the cell, and reduced ccid50 by 90% [81] . licorice and curcumin have recently been reviewed for their postulated antiviral potential [82] . other common traditional herbal remedies for respiratory viruses that have been supported by scientific evidence include berries' extracts, echinacea, clinacanthus siamensis, punica granatum (pomegranate), psidium guajava linn. (guava tea), epimedium koreanum nakai; scutellaria baicalensis georgi (baicalin), and paeonia lactiflora pall. (bai shao) [79] . examples of their antiviral role include reduction in viral replication, enhancement of anti-influenza virus igg and iga antibody production, improvement of t-cell function (e.g., stimulation of interferon-gamma production by t-cells), neuraminidase inhibitor, virus budding prevention, inhibition of viral rna and viral protein synthesis, viral haemagglutination, viral binding to and penetration into host cells [79] . fungi are also commonly used in asian and chinese medicine to enhance the immune system. for example, cordyceps militaris is a mushroom traditionally used for diverse pharmaceutical purposes in east asia, including china, for enhancing immunity. in a human study 1.5g/day of cordyceps militaris for 4 weeks enhanced the nk cell activity and lymphocyte proliferation and partially increased th cytokine secretion [83] . immune enhancing antiviral mechanisms of traditional medicine especially roots and fungi are important preventing and controlling novel influenza viruses, including covid-19. promising evidence has been shown about the restorative and antioxidative role of traditional medicinal herbs and peptides post trauma or physical challenges, which may be important in lung injury pathology. for example, the chinese ginseng rg1 herb has been shown to restore satellite cell depletion following an exercise challenge, through enhancing glutathione (gsh), and gssg [84] . gsh is considered important in immune modulation, remodeling of the extracellular matrix, apoptosis, and mitochondrial respiration through its gamma-glutamylcysteine synthetase heavy and light subunits oxidant/antioxidant response to phenolic antioxidants, and is considered key to the development of an oxidant/antioxidant imbalance in lung inflammation [85] . in another study it was shown that anserine, beta-alanyl-3-methyl-l-histidine, a dipeptide, replenished the free radical scavenging enzymes sod (superoxide dismutase) and preserved catalase and gsh cofactors, while preserving cell integrity and homeostasis, together with a haematological increase in red blood cell volume-to-concentration and an attenuated white blood cellelevation following muscular challenge in healthy men [24] . dietary intake of anserine, carnosine dipeptides, and other animal-based amino acids including taurine, creatine, and 4-hydroxyproline promote the immunological defence of humans against infections by bacteria, fungi, parasites, and viruses (including coronavirus) through enhancing the metabolism and functions of monocytes, macrophages, and other cells of the immune system [86, 87] . plant-based peptides from soybean have also been shown to modulate cellular immune systems (increased lymphocytes and granulocytes number, increased cd11b(+) cells and cd56(+) natural killer cells), regulate neurotransmitters (decreased adrenaline and increased dopamine), and boost brain function [88] . however, fish, meat, and poultry are the primary sources of immunomodulatory peptides and amino acids, and hence they have long been considered functional foods taken to alleviate fatigue, respiratory, and cold symptoms in older individuals, especially in asia [86, 87, 89] . plant cyclotides are well-studied antivirals, since they can be mimicked for antiviral drug development, given their stable chemical structure [90] . they have been originally extracted from african tea used in traditional african medicine to accelerate childbirth because of their postulated uteroactive antiviral hiv properties [90] . the protective mechanisms of plant cyclotides against infections and pathogens are postulated through preventing malfunctioning of the immune cells by growth-inhibiting growth effects on the human immune system especially on lymphocytes (e.g., t-cells), which can cause an over-reactivity of this defence machinery during infections [91] . cyclotides can be obtained from various plants including violaceae and rubiaceae, but are abundant in several other plant families, especially cucurbitaceae (e.g., squash, pumpkin, zucchini), fabaceae (legumes, peas, beans), and solanaceae (eggplant, tomato, potato, pepper). therefore, it is likely that consumption of such foods, especially seasonal intake plays a protective role in enhancing the immune system and enhances antiviral defence mechanisms. coffee, caffeine, and naturally caffeinated beverages are well known to induce various health benefits and prevention of disease. all forms of coffee consumption (differently roast beans, fermented or non-fermented leaves) are common across various cultures across the world for centuries [92, 93] . epidemiological evidence suggests that consuming 2-3 cups of coffee daily is associated with reduced incidence of metabolic diseases which are often concurrent with a compromised immune system such as diabetes [41, 94] . therefore, it is plausible to imply a positive role for caffeine as a useful immunomodulator. nutraceuticals within coffee have shown different antiviral outcomes, with caffeic acid inhibiting the multiplication of influenza a virus in vitro, whereas caffeine, quinic acid, and chlorogenic acid do not [95] . caffeic acid has also been shown to have antiviral activity against herpes simplex virus (dna virus) and polio virus (rna virus), and to decrease the progeny virus yield (especially within 3 h post-infection) and suppresses the degeneration of the virus-infected cells [95, 96] . however, caffeine reported immuno-protective mechanisms from laboratory in vivo and in vitro trials have been equivocal [97, 98] . positive caffeine effects on innate immunity involve suppression of neutrophil and monocyte chemotaxis, and pro-inflammatory cytokines (such as tnf-α) from human blood, but caffeine has also been reported to suppress antibody production and human lymphocyte function as indicated by reduced t-cell proliferation and impaired production of th1 (il-2 and interferon-gamma), th2 (il-4, il-5), and th3 (il-10) cytokines [99] . some of the immunomodulatory actions of caffeine have been explained by its inhibitions of cyclic adenosine monophosphate (camp)-phosphodiesterase, and consequential increase in intracellular camp concentrations [99] . however, recent in vitro evidence suggests that caffeine may suppress endotoxins lipopolysaccharide (lps)-induced inflammatory responses by regulating nuclear factor nf-κb activation and mapk phosphorylation [100] . lps activation of nf-κb triggers mucin transcriptors (e.g., muc2 gene) and respiratory tract mucus in response to respiratory pathogens including influenza viruses [101] . caffeine suppression of lps has also been reported in a recent human study in females with obesity [102] . the latter study also found that caffeine ameliorates the obesity-induced metabolic side-effects following intense exercise lifestyle intervention including elevated lps, insulin action, glucose homeostasis, and androgen levels. this suggests that caffeine optimizes the metabolic and immunoprotective benefits when combined with other lifestyle components, especially exercise. future research is needed to determine caffeine antiviral effects for the prevention and management of covid-19. exercise and physical activity enhance the immune system and reduce susceptibility to infections, especially respiratory infections including covid-19. moderate intensity exercise can be adopted by the large population including high-risk groups with ncds such as those with diabetes and cardiovascular disease. functional foods may provide a further effective diverse antiviral approach and could have a joint prevention of both ncds and cds among diverse populations. dietary intake of foods rich in vitamins and minerals can be increased to provide an immune boost, especially in individuals with deficiency in these micronutrients. increased intake of probiotics, omega-3 from fish, protein peptides from chicken and fish, and olive-based products are also recommended (table 1, figure 1 ). there is no specific model to follow to enhance the immune system against covid-19. however, the more varied the dietary sources, the better the protection is against all viral infections. adopting exercise together with an enhanced dietary intake of functional compounds may contribute as a preventative medicine against emerging viral infections. promote antioxidation and anti-inflammation properties, protect the respiratory system, and reduce risks of infection and re-infection [44] . cyclotides protect against infections and pathogens by preventing malfunctioning of the immune cells (t-cell lymphocytes), which reduces over-reactivity of this defence machinery during infections [91] . intake is highly recommended as part of a balanced diet. complements an active lifestyle, supports circadian rhythm, and sleep quality dairy products vitamins d, a, & e vitamin d reduces the risk of contracting respiratory infections and covid-19 [46, 64] . lowers viral replication rates through cathelicidins and defensins, and prevents lung injures that lead to pneumonia through anti-inflammatory cytokines [66] . dietary intake is preferred. supplements (zinc, selenium, and vitamin d) are recommended in older adults and the most deficient. enhances sleep quality. seeds and nuts zinc, selenium, copper, trace minerals contain phenolic compounds that are immunoprotective particularly through antioxidative and anti-inflammatory properties in high-risk adults [9] . supplementation is recommended when dietary intake is low, especially in older and high-risk individuals support inflammatory resolution and healing of infected sites including the respiratory tract, which could prevent acute lung injury, mainly through pro-resolving mediators (spms) such as resolvins, protectins, and maresins [7] . increased intake is recommended in high-risk individuals protein rich foods (e.g., red meat, chicken, seafood) amino acids and peptides: anserine, carnosine, taurine, creatine, and 4-hydroxyproline, vitamins, iron, copper dietary intake of anserine and carnosine promote immunological defence against infections by bacteria, fungi, parasites, and viruses (and coronavirus) through enhanced immune cell functions of monocytes and macrophages [24, 86] . plant peptides (e.g., soybean) increase lymphocytes and granulocytes; enhance natural killer activity [88] . dietary intake is sufficient, but an increased intake is recommended in high-risk individuals and infected patients. can be obtained from both animal and plant sources. olive based products (olive oil, olive leaves) oleuropein, hydroxytyrosol, elenolic acid, vitamin e reduced upper respiratory infection attributed to antioxidative property of oleanolic acid in oleuropein, especially influenza a and b, parainfluenza 1, 2, and 3 viruses, and herpes [69] . dietary intake (20-30 g/day), especially from extra-virgin olive oil, which is high in polyphenol content. increase benefits with physical activity. coffee (coffee leaves, differently fermented) caffeic acid, caffeine, polyphenols, chlorogenic acid caffeic acid decreases the progeny virus yield (especially within 3 h post-infection) and suppresses the degeneration of the virus-infected cells; caffeine can suppress of neutrophil and monocyte chemotaxis, and pro-inflammatory cytokines (e.g., tnf-α) [96] . it suppresses endotoxins lps-induced inflammatory responses (regulates nf-κb activation and mapk phosphorylation) [102] , and prevents mucosal response to pathogens infecting the respiratory tract and influenza viruses [101] . coffee intake (2-3 cups/daily) is recommended and has superior immunological benefit to caffeine supplementation since it is more wholesome (contains both caffeic acid and caffeine). roots & fungi, traditional herbs, and medicinal plants maoto, licorice roots, cordyceps mushrooms, chinese mushrooms, ginseng herbs and roots prevent viral replication, enhance anti-influenza virus igg and iga antibodies production, and 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potential as immunosuppressant peptides? effects of processing method and age of leaves on phytochemical profiles and bioactivity of coffee leaves a historical study of coffee in japanese and asian countries: focusing the medicinal uses in asian traditional medicines coffee consumption and risk of type 2 diabetes mellitus among middle-aged finnish men and women antiviral activities of coffee extracts in vitro inhibition by caffeic acid of the influenza a virus multiplication in vitro coffee and the immune system caffeine: well-known as psychotropic substance, but little as immunomodulator immunomodulatory effects of caffeine: friend or foe? caffeine prevents lps-induced inflammatory responses in raw264.7 cells and zebrafish the interaction between respiratory pathogens and mucus this article is an open access article distributed under the terms and conditions of the creative commons attribution (cc by) license author contributions: a.a. performed all parts of this work including concept, design, literature scoping and synthesis, and writing all parts of the manuscript. the author have read and agreed to the published version of the manuscript. the authors declare no conflict of interest. key: cord-010443-4jblod8j authors: meduri, gianfranco umberto; chrousos, george p. title: general adaptation in critical illness: glucocorticoid receptor-alpha master regulator of homeostatic corrections date: 2020-04-22 journal: front endocrinol (lausanne) doi: 10.3389/fendo.2020.00161 sha: doc_id: 10443 cord_uid: 4jblod8j in critical illness, homeostatic corrections representing the culmination of hundreds of millions of years of evolution, are modulated by the activated glucocorticoid receptor alpha (grα) and are associated with an enormous bioenergetic and metabolic cost. appreciation of how homeostatic corrections work and how they evolved provides a conceptual framework to understand the complex pathobiology of critical illness. emerging literature place the activated grα at the center of all phases of disease development and resolution, including activation and re-enforcement of innate immunity, downregulation of pro-inflammatory transcription factors, and restoration of anatomy and function. by the time critically ill patients necessitate vital organ support for survival, they have reached near exhaustion or exhaustion of neuroendocrine homeostatic compensation, cell bio-energetic and adaptation functions, and reserves of vital micronutrients. we review how critical illness-related corticosteroid insufficiency, mitochondrial dysfunction/damage, and hypovitaminosis collectively interact to accelerate an anti-homeostatic active process of natural selection. importantly, the allostatic overload imposed by these homeostatic corrections impacts negatively on both acute and long-term morbidity and mortality. since the bioenergetic and metabolic reserves to support homeostatic corrections are time-limited, early interventions should be directed at increasing grα and mitochondria number and function. present understanding of the activated gc-grα's role in immunomodulation and disease resolution should be taken into account when re-evaluating how to administer glucocorticoid treatment and co-interventions to improve cellular responsiveness. the activated grα interdependence with functional mitochondria and three vitamin reserves (b1, c, and d) provides a rationale for co-interventions that include prolonged glucocorticoid treatment in association with rapid correction of hypovitaminosis. in critical illness, homeostatic corrections representing the culmination of hundreds of millions of years of evolution, are modulated by the activated glucocorticoid receptor alpha (grα) and are associated with an enormous bioenergetic and metabolic cost. appreciation of how homeostatic corrections work and how they evolved provides a conceptual framework to understand the complex pathobiology of critical illness. emerging literature place the activated grα at the center of all phases of disease development and resolution, including activation and re-enforcement of innate immunity, downregulation of pro-inflammatory transcription factors, and restoration of anatomy and function. by the time critically ill patients necessitate vital organ support for survival, they have reached near exhaustion or exhaustion of neuroendocrine homeostatic compensation, cell bio-energetic and adaptation functions, and reserves of vital micronutrients. we review how critical illness-related corticosteroid insufficiency, mitochondrial dysfunction/damage, and hypovitaminosis collectively interact to accelerate an anti-homeostatic active process of natural selection. importantly, the allostatic overload imposed by these homeostatic corrections impacts negatively on both acute and long-term morbidity and mortality. since the bioenergetic and metabolic reserves to support homeostatic corrections are time-limited, early interventions should be directed at increasing grα and mitochondria number and function. present understanding of the activated gc-grα's role in immunomodulation and disease resolution should be taken into account when re-evaluating how to administer glucocorticoid treatment and co-interventions to improve cellular responsiveness. the activated grα interdependence with functional mitochondria and three vitamin reserves (b1, c, and d) provides a rationale for co-interventions that include prolonged glucocorticoid treatment in association with rapid correction of hypovitaminosis. keywords: critical illness, glucocorticoid receptor-alpha, nuclear factor-κb, mitochondria, hypovitaminosis the reasons behind the evolutionary success of mammals and other multicellular organisms is their extraordinary capacity to adapt to changing environmental conditions and survive by maintaining their homeostasis (1) . homeostasis refers to the relative stability in the activity of the physiological systems of the organism that are essential to support life (2) . the process of maintaining stability within a harmless range via homeostatic physiologic corrections to both predictable and unpredictable adverse forces or stressors is termed "eustasis" (2) . in the course of human evolution, homeostatic corrections have emerged to increase the host's ability to cope with adverse or even catastrophic events (3) . these responses are shaped by trade-offs, sometimes with benefits and disadvantages in different periods of the life cycle (4) . following the cambrian explosion, about 450 million years ago, when multicellular organisms-originally formed in water environments-colonized the land physiological homeostatic changes emerged to allow survival. these corrective changes were essential to mammalian species evolution and emerged to solve a frequent conflict between environmental changes and preservation of the individual allowing survival and, hence, reproduction. these alterations permitted progression to future generations i.e., survival of the species through the active process of natural selection (5) . these corrections involved profound neural, metabolic and immune changes mediated by a few major physiological systems (e.g., the central nervous, autonomic, cardiorespiratory, endocrine, and immune systems), and acting through integrated crosstalk pathways, that was associated with appropriate responses throughout the organism (5) . such changes have been relatively conserved across many vertebrates, including mammalian species (6, 7) . they have evolved to allow coping with lack of energy, dehydration, hemorrhage, infections, toxic substances, or relatively short-lived inflammatory responses, such as those of wound healing or exposure to foreign substances (7) . when the organism is exposed to stressors that exceed the harmless stability range, individual survival is maintained at the expense of this organism's health and longevity. this condition is different from healthy homeostasis or eustasis and is called "allo-stasis" or different (allo)-stasis or even more accurately "caco (bad) -stasis. the cumulative cost of cacostasis for the organism, has been called allostatic or cacostatic burden. excessive or prolonged cacostatic burden results in severe acute and/or chronic cacostatic pathology (2, 8) . the intensive care unit (icu) stress state represents a new and very different ecosystem from those within which humans evolved in the past. actually, critical illness epitomizes an acute and/or chronic cacostatic burden that goes beyond an evolutionarily conserved physiological adaptive response, and if left untreated it could rapidly exhaust homeostatic compensation and lead to death of an organism (lethal cacostasis). in critically ill patients, the need for vital organ support (maintenance of arterial blood pressure, mechanical ventilation, and other support measures, which were not available until the middle of the last century), reflects near exhaustion or exhaustion of (i) neuroendocrine homeostatic compensation, also known as "critical illness-related corticosteroid insufficiency" (circi) (8) ; (ii) cell bio-energetic and other functions; and (iii) reserves of vital micronutrients (vitamins and minerals). even when it allows survival of the patient, homeostatic failure, ranging in acuity and severity, has a major impact on morbidity and mortality during and after hospitalization. circi-associated dysregulated systemic inflammation and mitochondrial dysfunction are central to the increased morbidity and mortality of acute and/or chronic critical illness and the subject of this review. in multicellular organisms, the innate immune system with its recognition and signaling mechanisms is the most ancient form of host defense to infectious and non-infectious threats during evolution (9) . the nuclear factor-κb (nf-κb) system, a "rapidlyacting" primary transcription factor regulated cellular response, is a central activator of innate immunity. it appears that the nf-κb was incorporated into this ancient signaling pathway more than 420 million years ago, and has been shown to play independent roles in vertebrate and insect lineages (9, 10) . in most cell types, the inactive form of nf-κb, a heterodimeric protein composed of the dna-binding proteins p65 and p50, is retained in the cytosol by association with inhibitory factors, such as iκb proteins; when activated, the latter are rapidly phosphorylated and degraded via the proteasomal pathway, liberating nf-κb and allowing it to translocate into the nucleus (11) . in tumor necrosis factor-α (tnf-α)-stimulated hela cells, a genome-wide study identified 12,552 genome binding sites of p65 (12) . among the 1,667 distinct nf-κb target genes identified, nf-κb controlled the expression of 249 target genes, including inflammatory cytokines, chemokines, inflammatory enzymes, adhesion molecules, and immune system receptors, which are known to orchestrate the integrated inflammatory and immune responses. interestingly, an additional 626 identified nf-κb target genes were involved in metabolic processes (13) . in critical illness, nf-κb-driven systemic inflammation, also known as a "cytokine storm" (14) , activates a multi-system response that includes at least three major domains: (i) the stress system composed by the hypothalamic-pituitary-adrenal (hpa) axis and the locus caeruleus-norepinephrine/sympathetic nervous system activated to provide sufficient energy and hemodynamic stability to overcome the initial phase of critical illness (15) ; (ii) the acute-phase reaction (apr), which has several adaptive functions, including increasing the production of procoagulant factors in preparation for possible tissue damage (16) ; and (iii) the tissue defense response (tdr) of the target organs [ figure 1 ; (11, 17) ]. the main effectors of systemic inflammation are the inflammatory cytokines, the acutephase reactants, and the peripheral effectors of the sensory afferent nervous system. the inflammatory cytokines include tnf-α, interleukin-1β (il-1β), il-6, chemokines, and other mediators of inflammation. the acute-phase reactants are mostly of hepatic origin and include the c-reactive protein (crp), figure 1 | systemic inflammation-associated multi-system responses: stress, acute phase, tissue defense. systemic inflammation-associated multi-system response that includes at least three major domains: (i) the stress system composed by the hypothalamic-pituitary-adrenal (hpa) axis and the locus caeruleus-norepinephrine/sympathetic nervous system; (ii) the acute-phase reaction (apr), and (iii) the tissue defense response of the target organs. fibrinogen, and plasminogen activator inhibitor-1. during the acute-phase reaction, myelopoiesis is favored at the expense of both lymphopoiesis and hematopoiesis, explaining in part the persistent lymphopenia and anemia of critical illness (18) . substance p is an example of an effector of the sensory afferent nervous system, while hypothalamic corticotropin releasing hormone (crh), vasopressin, cortisol, the catecholamines (norepinephrine and epinephrine), and peripheral neuronal crh represent effectors of the stress system [reviewed in (19) ]. the tissue defense response is an integrated network of three simultaneously nf-κb-activated pathways that account for much of the histological, physiological, and laboratory changes observed in vital organs during critical illness (11) . these three pathways are those of tissue inflammation, hemostasis, and tissue damage repair: (i) tissue inflammation includes changes in the endothelium, such as loss of the glycocalyx, adhesion/diapedesis of activated neutrophils, endothelial injury, increased porosity with interstitial exudative edema, and loss of vascular tone, and changes in the epithelium, such as loss of integrity and cell apoptosis; (ii) the hemostasis pathway includes platelet activation and aggregation, intravascular clotting with decreased microvascular patency, extra-vascular fibrin deposition, and, lastly, inhibition of fibrinolysis, and (iii) tissue damage repair includes regenerating native parenchymal cells, fibroproliferation and deposition of extracellular matrix, resolution of granulation tissue, and clearance of apoptotic cells and debris (11) . the roles of macrophages and mitochondria in homeostatic corrections is the subject of intense research. mononuclear phagocytic cells (mpcs), including macrophages and dendritic cells, are widely distributed throughout the tissues of the organism, where they perform essential homeostatic, surveillance, and regenerative tasks. as the neuro-endocrine-immune response progresses, macrophages change phenotype and play an essential role in both innate and adaptive immune responses, in the resolution of inflammation and in the tissue repair and regeneration (discussed further in section glucocorticoid receptor-alpha and homeostatic corrections) (20) . mitochondria are targets of gr and critical modulators of homeostatic corrections owing to their critical role in energy production, synthesis of stress-associated steroid hormones, and their capacity to generate signals that promote cellular adaptation (see section cellular energetics-mitochondrial function) (21) . systemic homeostatic corrections are driven by elevated levels of circulating inflammatory cytokines, and based on disease progression, can be broadly divided into either adaptive/resolving (regulated systemic inflammation) vs. maladaptive/unresolving (dysregulated systemic inflammation) (11, 14) . evidence from the literature on severe sepsis (22) (23) (24) (25) (26) (27) (28) (29) (30) , acute respiratory distress syndrome (ards) (31) (32) (33) (34) (35) , and trauma (14, 36) provides strong support that the degree of nf-κb-driven elevation in inflammatory biomarkers at icu entry and during icu stay correlates with disease severity and hospital mortality (33, (37) (38) (39) . in addition to elevated inflammatory markers, critically ill patients have profound activation of the coagulation system (elevated d-dimer levels, prolonged prothrombin time and activated partial thromboplastin time, and reduced levels of the anticoagulant proteins, protein c and antithrombin) and evidence of endothelial cell activation with disturbed vascular integrity that correlates with disease severity and outcome (see section endothelium) (40) (41) (42) . evidence that hemostasis and inflammation evolved from a single-triggered mechanism can be traced back more than 450 million years ago, based on studies with the horse-shoe crab (limulus polyphemus) (43) . in hospital survivors, failure to achieve homeostatic correction has a significant negative long-term impact, with experimental work suggesting that it might potentiate the peripheral and brain pro-inflammatory cytokine response to a subsequent inflammatory challenge (44) . independently of age and comorbidities, patients with elevated circulating biomarkers of inflammation and hemostasis at hospital discharge have persistent elevation over time with increased risk for cardiovascular events, re-hospitalizations, and 1-year mortality (41, 45, 46) . "persistent inflammation, immunosuppression, and catabolism syndrome" (pics) has been postulated as the underlying pathophysiology of chronic critical illness (cci) (18, 47) . about 50% of sepsis patients have a debilitating condition characterized by a self-perpetuating cycle of persistent low-grade systemic inflammation mimicking chronic stress (elevated cortisol) (44, 48, 49) , glucocorticoid resistance, altered hemostasis (50, 51) , mitochondrial dysfunction (52, 53) , and accelerated inflamm-aging (9, 54) , with increased risk for chronic inflammatory systemic diseases (7, 55) . the evolutionary trade-off between acutely beneficial and chronically harmful homeostatic corrections was the subject of a recent review (7) . recently, a critical role was identified for the fkbp5 gene, which encodes the fk506 binding protein 51, a co-chaperone of the gr along heat shock proteins (hsp), including hsp90. the expression of fk506 is stimulated by glucocorticoids and has an inhibitory effect on gr signaling, preventing the nuclear translocation of gr. if short-lived, this negative feedback mechanism to reduce gc signaling may be important to restore hpa axis homeostasis. however, aging and certain stress-related phenotypes are associated with epigenetic upregulation of fkbp5 via decreases in dna methylation at selected enhancer-related fkbp5 sites, promoting nf-κbrelated peripheral inflammation and chemotaxis, and heightened cardiovascular risk (56) . importantly, translational research indicates that the type of response (regulated or dysregulated) is established early in critical illness (14, 31, 57) , and the previously espoused hypotheses of the second-hit model (14, 22) , or the two-phase model (compensatory anti-inflammatory response syndrome) are now both considered obsolete (29, 58, 59) . based on this pathophysiological construct, we will focus on emerging evidence indicating the central role played by the activated glucocorticoid receptor-alpha (grα), the master regulator of nf-κb and homeostatic corrections, in the development and resolution of critical illness. this role is conditioned by its interdependence with functioning mitochondria and by presence of adequate micronutrient reserves. additionally, we present evidence on how circi, mitochondrial dysfunction/damage, and hypovitaminosis negatively interact to accelerate an anti-homeostatic process of natural selection. the stress system is a complex, sophisticated, and carefully regulated adaptation mechanism that has been shaped by natural selection because it offers a selective advantage (4) . all vertebrates express the proopiomelanocortin protein (pomc) that gives rise to adrenocorticotropic hormone (acth) which then stimulates the secretion of glucocorticoids. acth has long been closely associated with other signaling molecules, such as crh, vasopressin, biogenic amines (epinephrine and norepinephrine), steroids such as cortisol and aldosterone, cytokines, such as il-1β, and nitric oxide. all of these substances are crucial to adaptation to stressors. it is remarkable that the gene dna sequences for these molecules have not only been conserved over hundreds of millions of years but also continue to serve closely related adaptive functions (4). this is apparently a result of strong selective forces against mutations that change their sequences and functionality of their products. cortisol, the end-product of hpa axis activation, is synthesized from cholesterol in the mitochondria and endoplasmic reticulum of the zona fasciculata of the adrenal cortex. its synthesis depends entirely on scavenger receptor class b type-i (sr-bi)-mediated cholesteryl ester selective uptake from circulating high-density (hdls) and low-density (ldls) lipoproteins (60) . in critically ill patients, low serum hdl levels correlate negatively with circulating tnf-α and il-6 levels (61, 62) , and positively with mortality (61, 63) . the combined effects of reduced hdl and sr-bi during systemic inflammation may lead to significant reductions in glucocorticoid production (64) . low hdl (65) and low total cholesterol (66) correlate with inadequate response to acth stimulation. in septic shock, prolonged glucocorticoid administration is associated with significant increase in total cholesterol levels within 3 days of treatment (66) . glucocorticoids are the primary adaptive response mediators, whose signaling system interacts with other cell signaling systems, all essential for maintaining the homeostasis of many of the body's complex functions, including neural, cardiorespiratory, endocrine, metabolic, bioenergetic, and immune responses (67) . within tissues, glucocorticoids are regulated at the pre-receptor level by the isozymes of 11βhydroxysteroid dehydrogenase (11β-hsd), which are located in the endoplasmic reticulum (er). glucocorticoids (gcs) bind to the ligand-binding domain of grα to produce a biological response. because of their lipophilic nature, gcs can readily diffuse across cellular membranes to bind to their intracellular receptor and produce a biological/pharmacological response [ figure 2 ; (15, 68, 69) ]. the glucocorticoid receptor is a member of the nuclear receptor (nrs) (70) superfamily that emerged in the vertebrate lineage ∼420-440 million years figure 2 | genomic, non-genomic, and mitochondrial glucocorticoid signaling pathways. glucocorticoid receptor mechanisms of action. the classic actions of grα are shown in the middle of the panel. the dormant but ligand-friendly receptor, located in the cytoplasm, is bound to co-chaperon molecules, such as heat-shock proteins and the immunophilin fkbp. upon binding to the ligand, the activated receptor translocates into the nucleus, where it interacts with gres and/or other transcription factors, such as nf-κb and ap1, to regulate the activity of glucocorticoid-responsive genes, which represent ∼20% of the human genome. in addition, cell membrane-associated grα may be activated by the mapk and pi3k kinases, as shown in the left of the panel. in addition, by as yet unknown mechanism, the grα translocates into the mitochondria, where it interacts with the mitochondrial dna gres, regulating the activity of mitochondrial genes. see text for additional details cpla2α, cytosolic phospholipase a2 alpha; enos, endothelial nitric oxide synthetase; fkbp, immunophilins; gr, glucocorticoid receptor; hsp, heat shock proteins; mapk, mitogen-activated protein kinases; no, nitric oxide; pi3 k, phosphatidylinositol 3-kinase; tf, transcription factor. ago (similarly to nf-κb) from sequential duplications of two ancestral genes, those of the estrogen and the glucocorticoid receptors; the latter ultimately evolved into the glucocorticoid and the mineralocorticoid receptors (67, 71) . underlying its essential role in formation and regulation of multicellular life, the gr is required to establish the necessary cellular context for maintaining normal uterine biology and fertility through the regulation of uterine-specific actions (72) while grs are vital for the structural and functional maturation of fetal organs (73, 74) , affecting almost 4,000 genes (75) . in late gestation of mammals, fetal glucocorticoid levels rise dramatically, an essential step for maturation in preparation for life after birth. also, an association was found between greater maternal affection and warmth in early life and increased expression of glucocorticoid receptor genes in the offspring resulting in long-term health benefits (76) . grs are present in the cytoplasm (68) and cell membrane (non-genomic effects) (77) in almost all cells of the body and in high concentrations (in neutrophils ∼5,000; in macrophages ∼10,000) (78). however, gr levels within the cell are not static, but are tightly controlled by numerous factors and at multiple levels. notably, 16 variants of the human gr (hgr) have been identified to date with the potential of at least 256 combinations of homo-and hetero-dimers (68) . recent research indicates that the expression of different gr transcriptional and translational isoforms might be a significant factor determining how gcs influence the biological function and activity of specific cells and tissues (75) . in contrast to grα, the alternatively transcribed grβ, which resides primarily in the cell nucleus, does not bind glucocorticoid, but can form homodimers with itself or heterodimers with a grα subtype, functioning as an antagonist of grα. grβ homodimers can interact with glucocorticoid response elements (gre) in the dna, however their binding does not activate transcription (69) . generally, grβ is expressed at very low levels compared to grα; however, its expression is increased in inflammatory diseases, including critical illness, and this might be associated with decreased sensitivity to gcs and circi (79) . activation of grα is not only an essential component of the general adaptation to stress, but also contributes to the maintenance of homeostasis in stress-free conditions (15) . the biological response to the gc-grα complex is affected by cell type, tissue type, and species-specific variations in the repertoire of partnering proteins, ligand concentrations, and other contextual variables (80, 81) . in stimulated hela and neuronal pc12 cells, genome-wide studies identified 8,306 and 2,252 gr genomic binding sites upon treatment with gc, respectively (12, 81) . of interest, the availability of these binding sites for interacting with the gc-gr complex depends on the chromatin landscape, which is tissue-and cell type-specific, explaining to some extent, why the gr has a certain effect on one tissue and a totally different effect on another (67) . thus, even though the signaling system is the same, the landscape of the landing site is not. thus, different cells recognize these signals differently, resulting in a highly context-dependent action by glucocorticoids (67) . after gc binding takes place in the cytoplasm, the activated gc-grα complex can either (i) bind to several pro-inflammatory transcription factors, or (ii) act as a transcription factor, after translocation into the nucleus and mitochondria (69, 82) . glucocorticoids regulation of mitochondrial transcription via activation of mtgre was the subject of a recent review (53) . in pathway (i), the activated gc-grα complex interacts directly with activated transcription factors nf-κb and ap-1, leading to the transcriptional repression of major downstream proinflammatory factors. in pathway (ii), gc-grα binds to positive (transactivation) or negative (transrepression) specific dna regions, the glucocorticoid-response elements (gres) on the nuclear and mitochondrial dna (83) , to directly regulate transcription of target genes. finally, gc activation of membrane-bound gr rapidly induces the activity of several kinases, such as the mitogen-activated protein kinase (mapk) or the phosphatidylinositol 3-kinase (pi3k) pathways [ figure 2 ; (69) ]. the non-genomic effects of gcs clearly differ from their well-known genomic effects, with the former responding within several minutes independently of protein synthesis. genomic studies have shown that the gc-grα complex regulates more than 3,000 genes in unstimulated peripheral blood mononuclear cells (pbmc) from healthy donors (84) , in human pulmonary type ii cells (85) , and several organs, including the heart (86), liver (87, 88) , and uterus (72) of unstimulated mice, underscoring its essential role as a master modulator in sustaining life and restoring health. the discordance between the number of regulated genes and the gr sites (12, 81) suggests that multiple sites are involved in the regulation of a single gene and/or that binding of a transcription factor is not sufficient to drive gene expression (12) . control of mrna turnover is critical in regulating the levels of inflammatory-and immune-mediated gene expression. recent studies indicate that the gr can mediate gc actions beyond transcriptional gene control; it may actually directly participate, via association with mrna, in gc-mediated control of cytoplasmic post-transcriptional mechanisms of gene expression (89) . in an experimental model (spret/ei mice), increased gr levels and activity were associated with strongly reduced expression levels of cytokines and chemokines in response to lps-induced lethal inflammation (90) . in 1984, munck et al. reviewed the actions of cortisol and proposed that "stress-induced increases in glucocorticoids levels protect, not against the source of stress itself, but rather against the body's normal reactions to stress, preventing those reactions from overshooting and threatening homeostasis (91) ." this work and the results of the above genomic studies have led to a reevaluation of glucocorticoids' role in homeostatic corrections. busillo and cidlowski (92) recently reviewed the master regulatory role played the activated gc-grα complex in the three major phases of homeostatic correction involved in disease development and resolution (figure 3 ). while distinctions are made between the different states, variable degrees of overlap are likely. first, in the pro-inflammatory phase, gc-grα prime the innate immune system to remove or neutralize pathogens by: (i) inducing the expression of tolllike receptor 2, nod-like receptor pyrin containing 3 (nlrp3) inflammasome, and purinergic receptor p2y2r; (ii) repressing adaptive immunity (energy conservation); and (iii) cooperating with pro-inflammatory transcription factors nf-κb and activator protein 1 (ap-1) in promoting leukocyte redistribution. the gc induction of nlrp3 sensitizes the cells to extracellular atp and significantly enhances the atp-mediated release of proinflammatory molecules, including mature il-1β, tnf-α, and il-6 (93). in addition, inflammatory cytokines, particularly il-6, nitric oxide, and gcs trigger and modulate the systemic and hepatic acute phase protein response (94) . in stimulated hela cells, a genome-wide study identified 1,932 gene collectively regulated by the activation of nf-κb and grα, with 43% of regulated genes responding only when both ligands are added, indicating that grα and nf-κb crosstalk alters signaling pathways that are regulated by each factor separately (12) . during systemic inflammation, peripherally generated tnfα, il-1β, il-6, and other inflammatory cytokines activate the hpa axis at multiple levels to produce gc (95) (96) (97) (98) . in addition, inflammatory cytokines increase the expression and enzymatic activity of 11β hydroxysteroid dehydrogenase type 1 (11βhsd1), which converts the inactive cortisone to the active cortisol in different cell types, as for example occurs after addition of tnf-α or il-1β on endothelial (99) or lung epithelial cells (100) . thus, cytokines seem to amplify gc bioavailability (101) . microarray studies have shown that tnf-α and gc synergistically co-regulate 210 genes involved in inflammation figure 3 | glucocorticoid receptorα as cellular rheostat of homeostatic corrections. the glucocorticoid receptorα (grα) acts as a cellular rheostat to ensure that a proper response is elicited by the neuroendocrine immune system throughout the three phases of homeostatic corrections: the pro-inflammatory (ready-reinforce), the anti-inflammatory (repress), and the resolution (resolve-restore) phase. modified with permission from busillo and cidlowski (92) . tlr2, toll-like receptor 2; purinergic receptor p2y2r; nlrp3, nod-like receptor pyrin containing 3; apr, acute phase response; tf, transcription factor; nf-κb, nuclear factor-κb; ap-1, activator protein 1; anxa1, annexina1; alxr, anxa1 receptor; gilz, glucocorticoid-induced leucine zipper; tgfβ, transforming growth factor β. (100) . in this context, the synergy between gcs and proinflammatory cytokines is a useful mechanism for rapidly reenforcing initial pro-inflammatory responses. importantly, gc-grα is necessary to prevent excessive phagocytic cell activation and improve intracellular bacterial killing (102) . in the second phase, when regulated systemic inflammation prevails, gc-grα exerts classic anti-inflammatory action by (i) inhibiting nf-κb, ap-1 and other signaling pathways involved in inflammation, and (ii) increasing transcription of anti-inflammatory genes and the nf-κb inhibitory protein iκb (68, 103) . gc-grα anti-inflammatory action has been extensively investigated, and we direct the reader to excellent reviews on the (11, 68, 101, (104) (105) (106) . in upcoming sections, we will review selected mechanisms involved in gc-grα failure to downregulate systemic inflammation and achieve disease resolution. the third phase involving disease resolution, i.e., restoration of tissue anatomy/structure and function, is an active and elegantly orchestrated process associated with multiple biochemical pathways, including switching production from pro-inflammatory to pro-resolving mediators (92) . as downregulation of systemic and tissue inflammation continues, the activated gc-grα engages in a host of pro-resolution mechanisms changing, among others, the phenotype of both granulocytes and macrophages. in these immune cells, via genomic mechanisms, gc-grα increases the expression of annexina1 (anxa1), anxa1 receptor (alxr), and glucocorticoid-induced leucine zipper (gilz), while via non-genomic mechanisms it increases the secretion of anxa1 (107) (108) (109) . the coordinated action of gilz and anxa1 is essential to regulating resolution (109) . granulocytes undergo constitutive apoptosis, disabling their potentially injurious secretion responses, i.e., nf-κb activation and transcription of inflammatory cytokines, and decreasing trans-endothelial migration leading to their rapid recognition and internalization by macrophages (efferocytosis) (109) (110) (111) (112) . apoptotic cells also serve as resolution cues for macrophages, which, after phagocytosis of apoptotic granulocytes, change their phenotype toward a more resolving/restorative one. the changes in phenotype from m1 (classically) to m2 (alternatively) leads to an orchestrated series of actions leading to successful resolution of inflammation. interestingly, gcs promote phagocytosis (112, 113) and reduce the apoptotic granulocyte ingestion requirements for generation of m2 (114) . gc-mediated change to m2 phenotype is associated with (i) immune silencing, where the release of inflammatory mediators and inducible nitric oxide synthase (inos) are suppressed (114) ; (ii) an increased release of the anti-inflammatory mediators il-10 and tgfβ and several pro-resolving lipid mediators (114); (iii) protection from apoptosis; (iv) non-phlogistic degradation; (v) production of angiogenic growth factors; (vi) increased macrophage chemokinesis (by upregulation of genes involved in cell mobility) and lymphatic clearance; and (vii) induction of acquired immunity (110, 111, (113) (114) (115) (116) (117) . gc-mediated annexin 1-derived peptide (ac 2−−26 ) acting through the alxr receptor has a pivotal role in the clearance of apoptotic cells (118) . in models of self-resolving inflammation, various phenotypes of macrophages may coexist. in the later phase of resolution, m2 macrophages switch to the resolution-promoting macrophage (mres) phenotype, which display reduced phagocytosis, while producing antifibrotic and antioxidant proteins that limit tissue damage and fibrosis (resolution of granulation tissue) (119) . in human monocytes, gcs induce the expression of 133 genes with upregulation of anti-oxidation, migration, phagocytosis, and anti-inflammation with consequent downregulation of adhesion, apoptosis, and oxidation (113) . in agreement with microarray data, spontaneous, as well as pma-induced production of reactive oxygen species, was significantly reduced in gc-treated cells, and gcs promoted survival of an anti-inflammatory monocytic phenotype in inflammatory reactions (113) . since grα ultimately controls gc-mediated activity, any condition that affects its concentration, binding affinity, transport to the nucleus, interactions with gres (nuclear and mitochondrial), cofactor activity (see section hypovitaminoses), or interaction of other relevant transcription factors (nf-κb, ap-1) and co-regulators, can eventually affect the response of cells to glucocorticoids (101, 120) . the many different ways grα function can be negatively influenced by the pro-inflammatory environment of critical illness was the subject of recent reviews (101, 121) . critical illness-related corticosteroid insufficiency is a term used to define the central role played by the hpa-axis and the activated grα complex in the pathogenesis of dysregulated systemic inflammation in critical illness (17) . three major pathophysiologic events account for the neuroendocrine decompensation observed in circi: (i) multi-level dysregulation of the hpa-axis correlating with circulating inflammatory cytokine levels; (ii) altered cortisol metabolism [reviewed in (122) ], and (iii) secondary generalized circulating and tissue specific reduction in grα number/function with observed multifactorial tissue resistance to endogenous glucocorticoids (17) . the role of mitochondrial oxidative stress in reducing grα number/function is reviewed later (see section oxidative stress and circi). experimental and clinical studies have demonstrated that critical illness is associated with a significant reduction in grα density and transcription and an increase in grβ-mediated dominant negative activity on grα-induced transcription. in a human cell line, activation of nf-κb by tnf-α had a direct doseand time-dependent effect on gr levels with a disproportionate increase in grβ over grα (123) . experimental sepsis is associated with decreased grα transcription in circulating cells (124) , heart (125), lymph node-spleen (124), liver (125) (126) (127) , kidney (127) , lung tissue (125) (126) (127) (128) (129) , and skeletal muscle (125) . moreover, the endothelial grα is required for protection against sepsis (see section endothelium) (130) . importantly, the reduction of grα expression is rapid and persists for at least 5 days (125) while it is associated with increased grβ expression in the heart and lung but not liver (125) , and increased nf-κb activation (127) . similarly, in experimental ards, lung tissue shows a significant reduction in grα expression (128, 131, 132) and an increase in grβ expression (131) , leading to decreased grα nuclear translocation (131) . in transgenic mice, expression of grα above wild-type levels leads to increased resistance to lps-induced endotoxic shock (133) . clinical studies, including autopsies, in patients with severe sepsis and septic shock have reported a significant reduction in grα expression in circulating cells (79, (134) (135) (136) (137) ; heart (125), liver and skeletal muscle (125, 138) , and a significant increase in grβ expression in the heart and liver (125) . grα mrna in neutrophils correlates negatively with plasma il-6 levels and shows gradual recovery overtime in survivors (135) . in another study, neutrophil grα mrna levels decreased 4fold by day 4 in the icu and remained low for 2 weeks (79). in ex vivo experiments with pbmcs exposed to longitudinal plasma samples from patients with ards results suggested that insufficient gc-grα-mediated activity at disease onset and over time was a central mechanism for the upregulation of nf-κb activity (figure 4) . over time, patients with regulated systemic inflammation have a progressive increase in all measured gc-grα-mediated activities, including grα number, binding to nf-κb and to nuclear gre, as well as increased transcription of iκbα and il-10, and a corresponding reduction in nf-κb nuclear binding, and transcription of tnf-α and il-1β. in contrast, patients with dysregulated systemic inflammation had only a modest longitudinal increase in gc-grα-mediated activities and a progressive increase in nf-κb nuclear binding that was most striking in non-survivors (33) . by day 3 of ards, no overlap was observed between groups for nf-κb and gc-grα nuclear binding. in lung tissue obtained by open lung biopsy, histological severity correlated with increased nuclear uptake of nf-κb and a lower ratio of grα: nf-kb uptake (33) . a decrease in grα expression in critical illness is maladaptive granted that proinflammatory pathways are not properly restrained (124) . randomized studies (103, 129, 132) demonstrated in both circulating and tissue cells, that quantitatively adequate and prolonged glucocorticoid supplementation increased grα number and function, reversing critical illness-associated cellular glucocorticoid resistance. in experimental ards, low-dose glucocorticoid treatment restored grα number and function leading to resolution of pulmonary inflammation (129, 132) . similarly, in an ex vivo ards study, prolonged methylprednisolone treatment was associated with upregulation in all measurements of grα activity leading to reduction in nf-κb dna-binding and transcription of inflammatory cytokines [ figure 4 ; (103) ]. glucocorticoid treatment changes the longitudinal direction of systemic inflammation from dysregulated (nf-κb-driven, maladaptive response) to regulated (grα-driven, adaptive response) with significant improvement in indices of alveolar-capillary membrane permeability and markers of inflammation, hemostasis, and tissue repair (11) . the vascular endothelium constitutes the innermost lining of the body's circulatory system and the largest tissue in the body figure 4 | correlation between mean levels of nuclear nf-κb and nuclear gc-grα during the natural progression of ards, and in response to prolonged glucocorticoid treatment. mean intracellular changes of nuclear gc-activated grα and nf-κb observed by exposing pbls of a healthy volunteer to plasma samples collected longitudinally (days 1, 3, 5, and 8) and after randomization to methylprednisolone treatment [randomization day (r) and post-randomization days 3, 5, 7, and 10]. the mean values of nuclear nf-κb are plotted against the mean nuclear gc-grα levels. improvers had a pre-defined improvement in lung injury score (139) and/or gas exchange component by day 7. the left panel shows ards patients with adaptive and maladaptive responses. in improvers, an inverse relation was observed between these two transcription factors, with the longitudinal direction of the interaction shifting to the left (decreased nf-κb) and upward (increased gc-grα). in contrast, in non-improvers nf-κb increased over time while gc-grα had no significant changes. we define the first interaction as gc-grα-driven, and the second interaction as nf-κb-driven (33) . the right panel shows non-improvers-survivors randomized after day 8 of ards to methylprednisolone (n = 11) vs. placebo (n = 6). after natural logarithmic transformation and adjustment for repeated measurements, partial correlations among responses to plasma from the methylprednisolone group were −0.92 (p < 0.0001) both for nuclear nf-κb and nuclear grα. for responses to plasma from the placebo group, no significant relation was found between nuclear nf-κb and nuclear grα (r = 0.11; p = 0.70) (103). reproduced with permission from meduri et al. (11) . (close to 100,000 miles long) containing ∼2.5 × 10 12 endothelial cells that are typically flat and susceptible to injury, with a thin basement membrane enriched in type iv collagen and laminin (140) . the endothelial lining is in continuous contact with circulating cells and soluble proteins, and the capillaries, represent the primary barrier between elements in the blood and the parenchymal cells. the space between two contiguous endothelial cells, known as the endothelial cleft (etc), acts as an important site of regulation of endothelial (paracellular) permeability (141) . importantly, the vascular endothelium (micro-and macro-circulation) is clothed with a protective barrier, the glycocalyx, which is critical to maintain endothelial homeostasis. the endothelial glycocalyx is a negatively charged, organized mesh of membranous glycoproteins and plasma proteins that include superoxide dismutase, antithrombin iii, and cell adhesion molecules, all involved in maintaining the oncotic gradient across the endothelial barrier (141) . the intact glycocalyx protects endothelial cells from oxidative stress and prevents the interaction between circulating leukocytes and endothelial adhesion molecules (141) . conformational changes in glycocalyx structure lead to short bursts in the release of endothelial nitric oxide (eno) (141), inhibiting vascular smooth muscle contraction, platelet aggregation, and leukocyte adhesion, all three processes essential for patency of microcirculation. the blood-brain barrier (bbb), composed of highly specialized endothelial cells with tight junctions that seal paracellular spaces to restrict permeability, serves as a highly restrictive interface between the systemic circulatory system and the brain (142). damage to the glycocalyx precedes vascular pathology. endothelial activation with ubiquitous shedding of the glycocalyx is a major component of critical illnesses and a key pathogenic mechanism in multiple organ dysfunction. the pathways by which sepsis induces injury to the endothelium were recently reviewed (143) . the "vasculo-centric view" of critical illness derives from the observation that, despite the remarkable heterogeneity of diseases, the pathobiology of multiple organ dysfunction shares near-stereotypical features that are mostly related to widespread endothelial dysfunction (144) . endothelial dysfunction manifests with a diffuse increase in paracellular permeability, expression of luminal cell adhesion molecules, recruitment of activate leukocytes, altered vasomotor tone, and microvascular thrombosis with decreased capillary density (145) . increasing evidence points to endothelial dysfunction with impairment of the bbb as a critical component of the pathobiology of delirium during critical illness (146) . oxidative stress (see section mitochondrial cacostatic load, oxidative stress, and mitochondrial damage) impairs endothelial function by interfering with eno synthesis (147) and by participating in the degradation of the glycocalyx (141) . after shedding of the glycocalyx, adhesion molecules are released in the blood and can be found in the circulation (35) . microvascular alterations, such as decreased functional capillary density and increased perfusion heterogeneity, are frequently observed in patients with sepsis and contribute to the defect in oxygen extraction by the peripheral organs and tissues of the organism (148) . endothelial activation may also affect the hpa-axis. the adrenal gland is a highly vascularized organ, with every steroidogenic cell in close vicinity with at least one sinusoid, and a clear positive relation between adrenal blood flow and steroidogenesis has been demonstrated (149) . in critical illness, disruption of endothelial homeostasis within the adrenal gland can contribute to the hpa-axis dysfunction (150) . hypovitaminosis may also contribute to endothelial dysfunction (see section hypovitaminoses). in studies of circulating inflammatory cytokines, there is substantial evidence that in critically ill patients, an increase in circulating markers of endothelial integrity (angiopoietin-1; angpt-1) (145), dysfunction [angiopoietin-2 (angpt-2), von willebrand factor (vvf) (150) , soluble intercellular adhesion molecule-1 (sicam-1), (35) vascular endothelial growth factor (vegf)] (145, 151) , and cell damage associated with circulating endothelial cells (152, 153) correlate with disease severity and mortality. fittingly, a large study acquiring sublingual measurements of microcirculation in early sepsis, found that mortality strongly correlated with the severity of alterations in the proportion of perfused small vessels, i.e., the functional capillary density (154) . the endothelial grα is a critical regulator of vascular homeostatic corrections and essential for decreasing the rolling on and adhesion of activated neutrophils to the endothelium (155) . in experimental sepsis, elimination of the endothelial grα resulted in prolonged activation of endothelial nf-κb, with increased expression of inos and inflammatory cytokines, both accounting for hemodynamic collapse and mortality (130) . importantly, the presence of the endothelial gr itself was necessary for gc-mediated suppression of nf-κb and for achieving survival (130) . grα also regulates the tightness of the bbb, inducing expression of the tight junction proteins occludin and claudin-5, and the adherens junction protein vascular endothelium cadherin (ve-cadherin) (156) . gc-grα is also strongly involved in vascular development (81) . experimental studies have shown gr-dependent upregulation of multiple mediators involved in endothelial cell homeostasis, such as sphingosine kinase 1 (sphk1) (157), angiopoietin-1 (angpt-1) (158), serum glucocorticoid kinase-1 (sgk-1) (159, 160) , gilz (161) , and enos (162) (163) (164) . in experimental ards, upregulation of sphk1, an important regulator of endothelial barrier integrity, was shown to improve alveolo-capillary membrane (acm) permeability (157) . in human brain microvascular endothelial cells (hbmecs), gc treatment was associated with transcriptional activation of angpt-1 and suppression of vegf (158) . in umbilical vein endothelial cells (huvecs), upregulation of sgk-1 reduced oxidative stress and improved cell survival and senescence (159) ; meanwhile, gr-induced gilz expression (see section glucocorticoid receptor-alpha and homeostatic corrections) correlated negatively with vascular inflammation (161) . in neuro-vascular tissue, physiological doses of hydrocortisone rapidly activated enos via non-genomic mechanisms (163, 164) . grα is also a critical regulator of myocardial function. in experimental work, the gr-via kruppel-like factor 13-was found to play a direct role in the regulation of cardiomyocyte function and protection from hypoxia and dna damage (86) . gr inhibits cells death triggered by ischemia reperfusion, mechanical stress, or tnfα [reviewed in (86) ]. the endothelial response to gcs in inflammatory diseases was extensively reviewed covering topics such as inhibition of proinflammatory transcription factors, restoration of endothelial barrier integrity, and induction of protective molecules (140) . in experimental sepsis, low-dose glucocorticoid (hydrocortisone or dexamethasone) preserved the endothelial glycocalyx, sustained the vascular barrier and reduced interstitial edema (165, 166) , and had beneficial effects on mesenteric blood flow and helped with resolution of organ injury (167) . gcs play an important role in the control of vascular smooth muscle tone by their permissive effects in potentiating vasoconstrictive responses to catecholamines and other hormones, such as argininevasopressin, through glucocorticoid receptors (168) . finally, they inhibit the expression of inducible nitric oxide synthase and other vasodilatory agents in vascular endothelial cells (169) . additional experimental studies have shown that gr stimulates transcription of the zonula occludens (zo)-1 tight junction protein, leading to reduced bbb paracellular permeability (142), while it activates enos increasing cerebral blood flow (163) . in patients with septic shock (170, 171) or ards (172, 173) , prolonged glucocorticoid (hydrocortisone or methylprednisolone) treatment resulted in the following: (i) increased plasma activated protein c levels (173); (ii) reduction in markers of endothelial injury such as sicam-1 (35); (iii) rapid and consistent improvement in capillary perfusion, independently of the cortisol response to acth (170) ; and (iv) improvement in alveolar-capillary (172) and renal (171) endothelial permeability. in addition, septic shock is associated with vascular dysfunction through nf-κb-mediated downregulation of the endothelial mineralocorticoid receptor (mr) and α1-adrenoceptor, which can be restored with mineralocorticoid (fludrocortisone) treatment (174) . a transforming event in the history of life was the evolution of photosynthetic bacteria, with biochemical pathways that allowed them to capture energy from sunlight and store it in simple sugars, a process known as photosynthesis that generates oxygen as a waste product. as a result, over the course of about one billion years, the earth's atmospheric oxygen increased from almost zero to nearly modern levels (175) . the development of an ozone layer in the upper atmosphere to absorb damaging uv radiation from the sun, a derived outcome of increased atmospheric oxygen, permitted organisms to live on land for the first time (175) . some groups of organisms adapted to increased oxygen levels; the most notable adaptation was the evolution of the biochemical pathways of cellular respiration, which use oxygen to extract the energy stored in organic molecules much more efficiently. about 2 billion years ago, complex life surfaced with two major endosymbiotic (eukaryotic cells ingesting a prokaryote bacterium that resulted in a symbiotic relationship between the engulfing and engulfed cells) events igniting the evolutionary progression to animals and plants (176, 177) . first, the ancestral eukaryotic cell engulfed an aerobic prokaryote bacterium (i.e., capable of using oxygen to produce energy) that eventually evolved into mitochondria (specialized for cellular respiration) populating the cell cytoplasm (modern heterotrophic eukaryote) to afford a selective advantage for survival (178) . in the second endosymbiotic event, the early eukaryotic cell engulfed a photosynthetic prokaryote bacterium that evolved into the chloroplast (modern photosynthetic eukaryote). central to the integrated actions of immune and neuroendocrine responses (3, 17, 179) is cellular energetics, involving the mobilization of energy resources from gc-grαmediated breakdown of glucose (via glycolysis), fatty acids and amino acids for mitochondrial energy production (180) . in fact, gcs were originally named by hans selye based on their ability to increase blood glucose concentration. activation of the hpa axis mobilizes these energetic substrates into the circulation within minutes, underscoring the widespread role of gc-grα in the regulation of systemic metabolism (181) . mammalian cells, apart from erythrocytes, contain within their cytoplasm hundreds to thousands of mitochondria, the number determined by the energy demand of each cell type. mitochondria are autonomous and highly dynamic doublemembrane organelles that function as the powerhouses of the cell and utilize ∼98% of total body oxygen consumption. oxidative phosphorylation (oxphos) is the metabolic pathway in the inner membrane of the mitochondria which use enzymes to oxidize ingested calories to produce adenosine triphosphate (atp) required for normal cell functioning. ultimately, this conversion provides energy for most cellular processes within the body intracellular reactions (gene transcription and translation, epigenetic modifications), hormonal changes in the endocrine system, structural changes in tissue, and behavioral and cognitive responses] (181) , and in theory, determines the limits of an organism adaptive capacity (21) . by virtue of their origins as aerobic bacteria, mitochondria have their dna, rna, and protein synthesis systems. the mitochondrial dna (mtdna) in our proto-eukaryotic ancestors was significantly larger in genetic complement, but transfer of mtdna encoded genes to the nucleus has occurred over the 1.5-2 billion years since the origin of the eukaryotic cell, and today the mammalian mtdna (inherited from the mother) encodes 13 polypeptides, two rrnas (12s and 16s) and 22 trnas that are essential for oxphos and proper cell function (178) . since the mtdna encodes for only a handful of proteins, mitochondria depend on the cell nucleus and other cellular compartments for most of their proteins and lipids (182) . in addition to being the major source of intracellular atp, mitochondria are deeply involved in signaling pathways, elicited by perturbations in homeostasis, which promote cell adaptation (183, 184) . mitochondria constantly generate reactive oxygen species (ros) as a by-product of substrate oxidation and oxidative phosphorylation, a physiological process that is normally kept in check by a diversified set of antioxidant defenses (184) . the introduction of oxygen to earth's early biosphere stimulated remarkable evolutionary adaptations, and in this context, ros should be viewed as an essential consequence and driver of evolution and survival over time (185) . reactive oxygen species are required in numerous physiological cell functions, such as cellular signaling systems linked to the transcriptional machinery, maintenance of vascular tone, oxygen sensing, and host defense against pathogens (186) . one of the mitochondrial oxidases, the nadph oxidase of polymorphonuclear leukocytes (primarily neutrophils), is pivotal to the body's defense against pathogenic microorganisms (187) . mitochondria are involved in a multitude of cellular processes, well-beyond their long-established role as the cell's powerhouse. these include processes such as intracellular calcium homeostasis (buffering of cytosolic calcium), regulation of mitochondrial metabolism, cell migration, production of biomolecules such as amino acids, lipids, hemes, purines, and steroid hormones (see section mitochondria and hpa-axis cross-talk), and activation of cell death pathways (188) . mitochondria trigger cell death pathways by two mechanisms, first via necrosis when atp levels fall below a certain threshold, and second via apoptosis through the release of mitochondrial cytochrome c into the cytoplasm (189) . mitochondrial integrity is, therefore, essential for the function and survival of cells, and several recent publications have highlighted the critical role played by these organelles in sustaining homeostatic corrections (82, (180) (181) (182) (190) (191) (192) . in critical illness, tissue oxygen consumption and total energy expenditure are increased, with intracellular metabolism boosted by up to 200% compared to the healthy state (193) . cells that represent the innate immune system, like neutrophils, and macrophages, are mainly responsible for the oxidative burst that takes place early in critical illness (194) along with the generation of ros and nitrogen oxygen species (rns) that are important for host defenses. in neutrophils of critically ill patients, oxidative activity correlates positively with the degree of intranuclear nf-κb expression (195) . according to the "mitohormesis theory, " when present in moderate amounts, ros and rns function as intracellular signaling molecules that may improve systemic defense mechanisms by inducing an adaptive response (196) . however, when intracellular ros and rns concentrations overwhelm antioxidant defenses, cell homeostasis becomes compromised (196) . for example, peroxidation of the mitochondrial lipid cardiolipin in the inner mitochondrial membrane leads to dissociation of cytochrome c, reduced production of atp, and increased generation of ros (197) . increased energy and metabolic demands associated with nf-κb-driven dysregulated systemic inflammation, leads to overproduction of ros and rns, resulting in significant damage of lipids, proteins, and nucleic acids, both within the mitochondria and in other compartments of the cell [ figure 5 ; (197) ]. oxidative stress is a predictor of mortality in septic shock patients (198) . glutathione is one of the most important redox buffers of the cells, as it can be found in all cell compartments and acts as a cofactor of several enzymes, helps in dna repair, scavenges ros (e.g., hydroxyl radicals, hydrogen peroxide, and lipid peroxides), and generates other antioxidants, such as ascorbic acid (see section hypovitaminoses) and tocopherols (194) . vitamins d and c upregulate glutathione synthesis and prevent depletion (see section hypovitaminoses) (199, 200) . the multi-level organization of mitochondrial molecular composition, structures, functions, and signaling roles within the cell was recently reviewed (201) . in laboratory models of sepsis, mitochondrial respiration is often increased in the early phase of illness, but consistently falls with protracted inflammation [reviewed in (202) ]. many clinical studies implicate mitochondrial dysfunction and bioenergetic failure as an important pathophysiological mechanism underlying dysregulated systemic inflammation-associated multiorgan dysfunction. in a study of skeletal muscle biopsies obtained in septic patients, an association was first reported between nitric oxide overproduction, antioxidant depletion, mitochondrial dysfunction, and decreased atp concentrations, with progression of multiorgan failure and mortality (203) . human septic cardiomyopathy is accompanied by widespread downregulation of cardiac mitochondrial genes and decrease in the expression of genes that govern cardiac myocyte contractility, analogous to the transcriptional reprogramming that occurs in myocardial hibernation (204). early sepsis is associated with a reduction in pbmc mitochondrial copy number, and a rise in markers of mitochondrial damage, in a linear relation to proinflammatory cytokine expression (205) . the pbmcs of patients with severe vs. less severe pneumonia have increased ros density, increased dna damage, and decreased superoxide dismutase (sod) concentrations (206) . loss of mitochondrial function may lead to compensatory secondary metabolism, glycolysis, to produce atp as well as lactate (207) . a epithelial cell line study demonstrated that this glycolytic switch is promoted by the activation of the redox sensitive phosphoinositide 3-kinase (pi3k) pathway and subsequent inactivation of glycogen synthase kinase-3β (gsk-3β) resulting in increased production of inflammatory cytokines and reduced sensitivity to glucocorticoids (207) . decades of laboratory and clinical studies have revealed that dysregulated systemic inflammation, including sepsis, is associated with significant macromolecular damage to mitochondria, particularly in the cells of highly metabolically active tissues, such as the liver, heart, kidneys, brain, and skeletal muscles (191, 208) . in contrast to nuclear dna, which is nonimmunogenic, mitochondrial dna resembles bacterial dna (see section cellular energetics-mitochondrial function) and acts as a damage-associated molecular pathogen (damp) to activate immune responses through toll-like receptor 9-mediated activation of nf-κb (209) and the nlrp3 inflammasome (210) . also, in comparison to nuclear dna, mtdna is 50-fold more sensitive to oxidative stress (191) , as its close proximity to the electron transport chain and the absence of chromatin proteins makes it an easy target for oxidative damage (197) . as a consequence of increased ros generation, mtdna can undergo several qualitative and/or quantitative alterations. recent studies have found that critically ill patients have decreased cellular mtdna levels and increased circulating cellfree mtdna levels (205, 210, 211) . in septic patients, mtdna depletion in circulating cells (mainly neutrophils) correlates with severity of illness (apache ii scores) (212), while high tnf-α expression in neutrophil lysates correlates with increased plasma mtdna levels (205) . the exact mechanism of mtdna delivery into the cytoplasm and then into the systemic circulation is currently unknown (189) . in icu patients with sepsis and ards, elevated plasma mtdna levels (>3,200 copies/µl) are associated with dysregulation of phospholipid metabolism (211) , and increased mortality (210) . the cycle of mtdna damage with loss of function of electron transport enzymes (atp depletion) and increased ros generation, a state in which the antioxidant systems are overwhelmed may eventually lead to cell death, a phenomenon known as the "toxic oxidative stress" (213) . in critical illness, impaired cell energy metabolism and mitochondrial damage augment systemic inflammation directly via nf-κb activation and indirectly by multi-level impairment of the hpa axis and gr homeostatic functions (see section oxidative stress and circi). effective homeostatic corrections in the adaptive response during the resolution of critical illness are associated with increased mitochondrial biogenesis, restoration of oxidative metabolism, and mitochondrial content (205) . in many studies, restoration of mitochondrial homeostatic functions was observed in association with improved organ recovery and survival [reviewed in (205) ]. the association between mitochondrial dysfunction, circulating cell-free mtdna, muscle wasting, sterile inflammation, and inflamm-aging was recently reviewed (189) . micronutrient deficiencies may also impair mitochondrial function. in septic patients, the marked early reduction in selenium levels may affect selenium-dependent anti-oxidants glutathione peroxidase and thioredoxin (214) . the role of hypovitaminoses on mitochondrial function is reviewed in section hypovitaminoses. abundant mitochondria are one of the most prominent ultrastructural features of the adrenocortical cells (208) in which intracellular steroidogenic cholesterol is ultimately converted to cortisol in a tightly controlled manner (82) . the central role of mitochondria in essential physiological processes has rendered these organelles a receiver and integrator hub of multiple regulatory signals (215) . mitochondria participate in the stress response, in part, by sensing levels of glucocorticoids (183) . it is now accepted that mitochondria are under gc control because grs are present in mitochondria, and gres reside in the mitochondrial genome (82, 192) . a number of studies in several tissues have observed a cytoplasmic-to-mitochondrion gr translocation or vice versa in response to gc, indicating that mitochondrial gr is dynamically regulated upon exposure to gcs (69). lee and collaborators have classified five pathways in the functional modulation of the mitochondria by gc-gr (82) . in addition to direct mitochondrial gr-mtgre interactions, mitochondrial gene expression is regulated indirectly by nuclear gr-nugre interactions that result in increased transcription of the following: (i) genes encoding oxphos and other mitochondrial regulatory functions, (ii) transcription factors for control of nudna-encoded mitochondrial proteins, and (iii) several antioxidant mechanisms including uncoupling protein-2 (ucp2) (69, 82, 113, 192, 216, 217) . of interest, mitochondrial thioredoxin, an antioxidant and anti-apoptotic factor essential for cell viability and vascular homeostasis (218) , interacts directly with both the ligand and the dna-binding domains of gr, keeping the receptor in a reduced, transcriptionally active form (219, 220) . studies have shown that fine-tuning of the response to cellular demands is coordinately regulated by the nucleus and mitochondria, making mitochondrial-nuclear interaction vital to optimal mitochondrial function (82), with gc-grmediated increased mtdna gene expression augmenting the total number of mitochondria per cell, and, thus, total cellular energy production capacity (216). altogether, there is substantial evidence that cross-talk between neuroendocrine control of the stress response and cellular antioxidant systems is essential for mammalian homeostatic regulation (220) . consistent with the cacostatic load model (21) , administration of physiological doses of gcs acutely increases mitochondrial membrane potential, calcium buffering capacity, anti-oxidant capacity, and resistance to apoptotic signaling (8) , whereas chronic exposure to high doses of gcs suppresses anti-oxidant capacity, decreases mitochondrial membrane potential, and sensitizes cells to apoptosis (21, 187, 190) . oxidative stress is accompanied by multi-level impairment of the hpa axis and gr homeostatic functions (figure 5) . in non-survivors of septic shock, marked overexpression of inos in hypothalamic parvocellular neurons (pvn) was associated with decreased expression of pituitary acth, suggesting that the pro-apoptotic action of inos in the pvn may partially account for reduced activity of the hpa axis in sustained septic shock (221, 222) . in experimental sepsis, adrenal cellular extracts demonstrate a pronounced increase in mrna for inos and inflammatory cytokines that correlate positively with the degree of neutrophil infiltration, adrenal cell apoptosis, and mortality (213) . changes within the adrenal gland microenvironment may also affect the hpa axis response in critical illness (149) , with mitochondrial damage leading to a decreased responsiveness to acth (208) . importantly, inos expression in adrenal cells diverges at 48 h, with a significant increase observed in nonsurvivors vs. a reduction in survivors (223) . in experimental endotoxemia, nf-κb-mediated inos release is associated with mitochondrial oxidative stress in adrenocortical cells with inhibition of steroidogenesis and response to acth (208) . oxidative stress has a direct deleterious impact on grs number and function. experimental studies involving tissue cultures (220, (224) (225) (226) and murine models (227, 228) have demonstrated that oxidative stress is associated with decreased: (i) gr number (228) , (ii) gc binding to gr (220, (224) (225) (226) (227) , (iii) gc-gr nuclear translocation (226, 229) , (iv) binding to dna (224) , and (v) inducible gene transcription (220, 225) . nitrosylation, the covalent incorporation of a nitric oxide "nitrosyl" moiety into the critical cysteine(s) residue(s) of the gr is associated with loss of the steroid binding capacity (230) . in human monocytes, genes involved in oxidative functions were significantly overrepresented among gc down-regulated genes, while genes with antioxidant functions were upregulated (113) . a few studies have evaluated the impact of gc treatment on oxidative stress. in human monocytes, spontaneous, as well as phorbol myristyl acetate (pma)-induced production of reactive oxygen species, is significantly reduced in gc-treated cells in comparison to controls (113) . in murine macrophages, glucocorticoid treatment is associated with rapid (non-genomic) inhibition of superoxide anion production (231) . in murine sepsis, gc treatment attenuated renal dysfunction by reducing mitochondrial injury with preservation of cytochrome c oxidase and suppression of pro-apoptotic protein levels (232) . in clinical (233, 234) and experimental (162, 235) randomized trials, participants with severe sepsis receiving gc treatment had, in comparison to controls, a significant reduction in (i) circulating nitric oxide levels (162, 233, 235) , and (ii) spontaneous release of hydrogen peroxide (h 2 o 2 ) by neutrophils (234) . metabolic homeostasis is substantially disrupted in critical illness, and the degree of a vitamin deficiency can negatively impact health outcomes. three vitamins, namely thiamine (vitamin b1), ascorbic acid (vitamin c), and vitamin d, are important for the proper function of the gr system and mitochondria, and their reserves are rapidly exhausted in critical illness (236) . vitamins b1, c, and d impact mitochondrial function, while vitamins c and d also impact gr function. a comprehensive list of suggested mechanisms for the efficacy of thiamine, ascorbic acid, and glucocorticoids in sepsis was recently reviewed (237) . thiamine is a water-soluble vitamin, which is passively absorbed in the small intestine. after ingestion, free thiamine is converted to the active form thiamine pyrophosphate (tpp), commonly known as vitamin b1, by thiamine pyrophosphokinase. the majority of tpp in the body is found in erythrocytes and accounts for ∼80% of the body's total storage (238) . thiamine pyrophosphate is a key co-factor for pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase, transketolase, and branchedchain keto-acid dehydrogenase (238) . pyruvate dehydrogenase is the gatekeeper for entry into the krebs cycle, without which pyruvate would be converted to lactate as opposed to acetylcoenzyme a. alpha-ketoglutarate dehydrogenase is required for completion of the krebs cycle once it has begun. transketolase is a key enzyme for the pentose phosphate pathway and for the production of nadph with glutathione cycling, an important anti-oxidant pathway (239) . there are also other proposed non-cofactor roles of thiamine within the immune system, gene regulation, oxidative stress response, cholinergic activity, chloride channel function, and neurotransmission (238) . the human adult can store around 30 mg of thiamine in muscle tissue, liver and kidneys, however, these stores can become depleted in as little as 18 days after the cessation of thiamine intake (238) . a thiamine deficiency syndrome, beriberi, bears a number of similarities to sepsis, including peripheral vasodilation, cardiac dysfunction, and elevated lactate levels (237) . in critical illness, the prevalence of thiamine deficiency is 10-20% upon admission (198, 240) and can increase up to 71% during icu stay, suggesting rapid depletion of this vitamin (198) . based on limited data, no association was detected between thiamine levels, markers of oxidative stress (198) and mortality (198, 241) . in one study, a significant negative correlation was reported between thiamine and lactic acid levels in patients with sepsis without liver dysfunction (240) . in a pilot randomized controlled trial (rct) of patients with septic shock (n = 88), the administration of thiamine (200 mg twice a day for 7 days) reduced lactate levels and improved mortality over time in a predefined subgroup of patients with thiamine deficiency (35% of cohort) (239) . in a retrospective, single-center, matched cohort study, administration of thiamine within 24 h of septic shock (n = 123) was associated with improved likelihood of lactate clearance and a reduction in 28-day mortality (242) . despite some promising results, there is insufficient evidence to support or reject thiamine supplementation as a monotherapy in critically ill patients (238) . vitamin d is an ancient molecule that functions as both a nutrient and a hormone with metabolic and immunomodulatory properties; it regulates over 1,000 genes of the human genome (243, 244) . the vitamin d receptor (vdr) is a member of the nuclear receptor gene family and is expressed in virtually all nucleated cells. decreased serum levels of vitamin d have been associated with several autoimmune inflammatory diseases. genome-and transcriptome-wide studies indicate that vitamin d signaling modulates many inflammatory responses on several levels (245) , including interference with nf-κb, via upregulation of iκb expression (246) . in addition, the ability of vitamin d to inhibit metabolic stress and energy expenditure in a cell microenvironment suggests that this pleiotropic hormone has a broad task as a pro-survival agent (244) . a growing body of scientific and medical literature supports the important anti-inflammatory functions of vitamin d in health and disease, including the enhancement of gc-mediated anti-inflammatory actions (247) . the anti-inflammatory effect of vitamin d was consistently observed in studies of cell lines and human pbmcs, and was the subject of a comprehensive review (248) . pbmcs activated with tlr ligands after incubation with 1,25(oh)d3 showed decreased release of tnf-α and il-1β and increased anti-bacterial activity (249) . in pbmcs, physiologic levels of vitamin d reduce inflammatory activities, by upregulating gc-mediated mitogen activated protein kinase (mapk; see section glucocorticoid receptor-alpha) phosphatase-1 (mkp-1) (250) to down-regulate p38 mapkmediated inflammatory gene expression (including tnf-α, il-1β, il-6, and il-8) (251) . in lps-activated pbmcs (247) and pbmcs from patients with asthma (252), vitamin d enhanced dexamethasone-induced expression of mkp-1 (247) , and this synergism was dependent on vitamin d-induced gm-csf release (247) . one study suggested that the interaction between vitamin d, glucocorticoids and their cognate receptors is related to the duration of exposure to vitamin d (253) . beside this indirect modulation of signaling cascades, vitamin d and its receptor complex vdr/rxr can interact directly with the gc receptor and other transcription factors (245) . of interest, vitamin d has a high affinity binding for the gr (254) , and was recently shown to increase, in a dosedependent manner, gr concentration in t cells (255) . based on its pleiotropic functions, vitamin d is considered a "master tuner" in shifting homeostatic balance from a pro-inflammatory to a pro-resolving status (244) . several studies demonstrated a dose-dependent response of vitamin d with respect to reducing inflammation, with 1 nm and 10 nm concentrations causing the greatest effects (248) . one study showed that serum 25(oh)d levels as high as 120 nmol/l may be necessary for optimal immune function (256) . a small study in healthy patients with hypovitaminosis d reported that significant antiinflammatory benefits of vitamin d supplementation were only seen by achieving serum 25(oh)d levels greater than 100 nmol/l (256) . the mitochondria also appear to be a direct target of the vitamin d endocrine system, and the two most important enzymes responsible for activation or inactivation of 25(oh)d, namely cyp27b1 (1α-hydroxylase) and cyp24a1 (24-hydroxylase), are located in the mitochondria (257) . in u937 monocytes, 1,25 (oh)2 vitamin d upregulates glutamate cysteine ligase (gclc) and glutathione reductase (gr), resulting in an increase of cellular glutathione formation, and decreased ros and il-8 secretion (258) . two recent studies have evaluated the impact of vitamin d on skeletal muscle mitochondrial function. primary human skeletal muscle cells treated with 1,25(oh)d3 vs. vehicle demonstrated marked effects on mitochondrial number, morphology, physiology, and expression of key mitochondrial proteins, resulting in increased atp production (259) . in vitamin d-deficient symptomatic patients, vitamin d supplementation was found, using phosphorus-31 magnetic resonance spectroscopy, to augment muscle mitochondrial maximal oxidative phosphorylation after exercise and improved symptoms of fatigue (260) . treatment of skeletal muscle with vitamin d is associated with a change in expression of ∼83 nuclear mrnas encoding proteins known to localize in mitochondria (259) . hypovitaminosis d is common in critical illness, despite parallel elevations of pth (249) with one small study reporting a progressive drop in vitamin d levels in the first week of illness (261), while a low 25(oh)d3 status was significantly associated with all-cause and sepsis mortality (236) . in early critical illness, vitamin d status is associated with a differential metabolic profile. glutathione and glutamate metabolism, which play principal roles in redox regulation and immunomodulation, respectively, were significantly upregulated by vitamin d (199) . however, evidence of a mortality benefit of vitamin d as monotherapy still remains uncertain (262, 263) . a recent large rct investigated a single dose of 540,000 international units of vitamin d 3 in critically ill patients with 1,25(oh)d3 levels <20 ng/ml (264). by day 3, the treated group achieved a level of 25-hydroxyvitamin d of 46.9 ± 23.2 ng/ml; measurements of systemic inflammation were not reported. treatment was not associated with improvement in mortality or secondary variables (264). ascorbic acid (vitamin c) is a potent water-soluble antioxidant and an enzymatic cofactor that plays a key role in neuroendocrine and immune homeostatic corrections (265) . most vertebrates can synthesize ascorbic acid from glucose-6-phospate in the liver, with synthesis increasing during stress. in humans and other primates, however, ascorbic acid cannot be synthesized and has to be obtained through the diet. this is the result of a random mutation in the enzyme that catalyzes the final step of ascorbic acid biosynthesis in the common ancestor of the teleost fish some 200 million years ago (266, 267) . to date, there is no satisfactory evolutionary explanation for this apparent random loss of ascorbic acid synthetic ability. individuals from species which have lost the ability to make their own ascorbic acid were not selected against, as long as their diet contained sufficient quantities of vitamin c (266) . ascorbic acid is actively transported into all cells of the body (except erythrocytes) by the sodium vitamin c transporter-2 (msvct2). ascorbic acid is differentially accumulated by most tissues and body fluids. studies using radiolabeled ascorbic acid predict that body stores in healthy humans are about 1,500 mg; scurvy is thought to occur when this level falls below 300 mg, with plasma ascorbic acid concentrations <11.3 µm (268). importantly, the highest concentrations (µm) of ascorbic acid are found in critical organs involved in homeostatic corrections, such as the pituitary gland (2,300-2,800), the adrenals (1,700-2,300), the brain norepinephrine-synthesizing nuclei (800-900), and liver (600-900) (268) . this vitamin-sequestering may represent an evolutionary protective or "safety" function. ascorbic acid is a key cellular antioxidant. as such, ascorbic acid is an electron donor that directly scavenges for free radicals, and inhibits the generation of new free radicals through its suppressive effects on the nadph oxidase (nox) pathway (237) . ascorbic acid also prevents the depletion of other circulatory antioxidants, such as lipid-soluble vitamin e and glutathione, although this is not the case in reverse (200) . the anti-oxidant effects of ascorbic acid result in reduced endothelial permeability, improved microvascular and macrovascular function, attenuated cellular apoptosis in pathological states, and improved gr function (237) . ascorbic acid is maintained at high levels in mature circulating leukocytes (µm amounts in lymphocytes ∼3,800; monocytes ∼3,100, and neutrophils ∼1,400) (268), suggesting an important role in many aspects of the immune response. in leukocytes, ascorbic acid content responds to variations in plasma ascorbate availability (269) . following activation, immune cells undergo dramatic metabolic reprogramming with increased aerobic glycolytic activity and fatty acid oxidation (warburg effect) under the regulation of hypoxia-inducible factors (hifs) (270) . the result of this change is to rapidly provide atp and metabolic intermediates for the biosynthesis of immune and inflammatory mediators. importantly, the hydroxylase enzymes that regulate the actions of the hifs require ascorbate for optimal activity (269) . the immune-enhancing properties of ascorbic acid regulation of hifs include increased neutrophil and macrophage bacterial killing and phagocytic capacity (269, 271) . in addition, ascorbic acid plays an important role in protecting host cells from the excessive oxidative stress caused by infections (265) . ascorbic acid plays a crucial role in hpa axis function (figure 6 ). in adrenocortical cells ascorbic acid is sequestered in two pools, one of which can be depleted by acth. in response to inflammatory cytokine-mediated acth release from the anterior pituitary gland, the adrenal gland rapidly secretes ascorbic acid in amounts that are sufficient to increase, by several fold, plasma ascorbic acid concentrations in the adrenal vein, without increasing systemic levels (268) . more than 80 years ago hans selye, the pioneer of stress research, reported that the adrenal glands not only contain some of the highest concentrations of ascorbic acid in the human body, but they also employ this vitamin to synthesize cortisol in the adrenal cells (272) . today, in vitro and in vivo studies have shown that ascorbic acid is an essential cofactor required in both adrenal mitochondrial steroidogenesis and catecholamine biosynthesis (272) . the level of ascorbate in the adrenals might affect their capacity to convert cholesterol into pregnenolone, the precursor from which nearly all steroid hormones, including cortisol, are made (273) . additionally, ascorbic acid, as an antioxidant, has a positive impact on gr functions (see section oxidative stress and circi). oxidative conditions modulate negatively ligand-dependent and independent nuclear import of the gr, affecting gc-grα dna binding, and inducible gene expression (225, 229) , while a phosphodiester compound of ascorbic acid reverses oxidation of the gr, thereby, restoring the cellular glucocorticoidresponsiveness in oxidant conditions (225) . finally, the cellular uptake of ascorbic acid, mediated by msvct2, is downregulated during inflammatory conditions. in a time and concentrationdependent manner, gcs increase the expression of msvct2, facilitating the uptake of vitamin c into cells (274) , providing the rationale for combination treatment using gcs and ascorbic acid (275) . interestingly, there is a strong inverse correlation between the ability of an animal to endogenously produce vitamin c and the induction of a cortisol response when stressed (276) . in human cell lines and primary endothelial cells (ecv304 and huvec), ascorbic acid inhibits tnfα and il-1βinduced activation of nf-κb, in a dose-dependent manner, by inhibiting phosphorylation and degradation of iκbα (277, 278) , independently of its antioxidant properties (277) . preclinical studies show that high-dose vitamin c can prevent or restore microcirculatory flow impairment, reinstate vascular responsiveness to vasoconstrictors, and preserve the endothelial barrier (200) . both ascorbic acid (279) and the gr (see section endothelium) (130) are essential for endothelial cell homeostasis, and the combination of glucocorticoids with ascorbic acid is superior to either one on its own in protecting vascular endothelium that is critical to allow recovery (280) . many studies have demonstrated that vitamin c levels are rapidly depleted in critically ill patients, with about 40% of the septic patients having reduced serum levels, similar to those seen at scurvy diagnosis (<11.3 u/mol/l) (281, 282) . as intracellular ascorbate concentrations in mononuclear leukocytes and in granulocytes are, respectively, 80 and 25 times higher than in plasma, a high production and turnover of these cells may also contribute to its depletion (200) . low plasma concentrations of vitamin c are associated with more severe organ failure and increased risk of mortality (282) . similar to thiamine, ascorbic acid deficiency syndrome (scurvy) bears a number of similarities to sepsis, including coagulation abnormalities, and breakdown of the endothelial wall (282) . in a phase i safety trial, intravenous ascorbic acid infusion was safe, well-tolerated, and associated with improvement in multiple organ dysfunction and decreased biomarkers of inflammation and endothelial injury (281) . additionally, a small rct investigating high dose ascorbic acid administration in patients with septic shock reported a reduction in 28-day mortality (283) , while a larger trial in patients with sepsis-associated ards reported a significant reduction in 28-day all-cause mortality in response to acth release from the corticotrophs of the anterior pituitary gland, the adrenal gland rapidly secretes ascorbic acid, an essential cofactor required for adrenal steroidogenesis in mitochondria, contributing to increased glucocorticoids synthesis. (bottom) cells: glucocorticoids, in a time-and concentration-dependent manner, increase the expression of msvct2, facilitating the uptake of ascorbic acid into the cell. ascorbic acid reverses oxidation of the gr, restoring cellular glucocorticoid-responsiveness in oxidant conditions. in addition, ascorbic acid inhibits tnfα-and il-1β-induced activation of nf-κb in a dose-dependent manner by inhibiting phosphorylation and degradation of iκbα. these combined actions result in increased glucocorticoid availability and gc-grα activation and improved homeostatic corrections. (secondary outcome) (284) . the rationale for glucocorticoid treatment in association with high dose ascorbic acid was the subject of recent reviews (237, 267) . the promising findings of a recent retrospective study in patients with severe sepsis and septic shock has spurred considerable interest in the subject (275) . randomized data to confirm or refute the observational evidence for the drug combination are needed, and several clinical trials are ongoing or planned in the near future (237) . in critical illness, homeostatic corrections, the culmination of millions of years of evolution, are modulated by the activated gc-grα and associated with an enormous bioenergetic and metabolic cost. we have reviewed how circi, mitochondrial dysfunction/damage, and hypovitaminosis collectively interact to accelerate an anti-homeostatic active process of natural selection. importantly, the allostatic overload imposed by homeostatic corrections impacts negatively on both acute and long-term morbidity and mortality, while the bioenergetic and metabolic reserves to support homeostatic corrections are time limited. for these reasons it is prudent to implement early interventions designed to achieve the following: (i) reinforce innate immunity, (ii) inhibit further systemic tissue damage, (iii) limit the metabolic and bioenergetic cacostatic overload imposed during vital organ support, (iv) accelerate disease resolution, and (v) prevent persistent-chronic low-grade systemic inflammation (285) . this approach is supported by experimental (286) and clinical studies in patients with septic shock or ards (287) (288) (289) (290) . the actions of the activated grα cannot be categorized as merely anti-inflammatory, as it is now clear that insufficient intracellular grα regulatory action and not relative adrenal insufficiency is the primary driver of circi (17) . therefore, glucocorticoid treatment should not be viewed exclusively as anti-inflammatory or as a hormone replacement for relative adrenal insufficiency. it also is equally relevant that one should recall that full biological resolution lags weeks behind clinical resolution of an acute illness, making the clinical criteria that we frequently employ to guide duration of treatment, an inadequate reference point (291) . for these reasons, glucocorticoid treatment, and other co-interventions should be directed at supporting the activated grα regulatory function throughout all phases of homeostatic corrections, and not limited to the acute phase of organ support. randomized studies provide evidence that prolonged glucocorticoid administration is associated with increased grα number and function and decreased oxidative stress (see sections glucocorticoid receptor alpha in critical illness and mitochondria and hpa-axis cross-talk). additionally, the activated grα interdependence with functional mitochondria and three vitamin reserves provides a rationale for cointerventions that include rapid replacement of vitamins b1, c, and d. recent evidence generated from a retrospective before-after clinical study in patients with severe sepsis has generated momentum for increased research in this field (275) , with ongoing confirmatory randomized trials in progress (282) . additional co-intervention with critical hormones and mediators involved in homeostatic corrections are also necessary, such as fludrocortisone (174, 292, 293) or vasopressin (294) (295) (296) in patients with septic shock. fludrocortisone is a mineralocorticoid and glucocorticoid receptor agonist that binds to cytoplasmic receptors, activates their translocation into the nucleus and subsequently initiates the transcription of mineralocorticoid-and glucocorticoid-responsive genes (297). the inclusion or exclusion of fludrocortisone, as a cointervention with hydrocortisone, may partly explain the differences reported in outcomes of some rcts (see explanation for figure 7 below) (292, 298) . other potential co-interventions directed at increasing glucocorticoid receptor expression, such as statins (299), melatonin (300), beta-blockers (301), calcium channel blockers (301) , or directed at improving mitochondrial function (194, 302, 303) have not been investigated in association with glucocorticoid treatment in acute illness or alone in chronic critical illness. present understanding of the activated gc-grα's role in immunomodulation and disease resolution should be taken into account when re-evaluating how to administer glucocorticoid treatment and in monitoring treatment responses. there are many variables to consider, including the type of gc to be used, timing, dosage, mode of delivery, co-interventions, duration, and tapering. over the last 40 years, multiple randomized trials investigating gc treatment in critical illness have clearly shown that the design of a treatment protocol has a profound impact on treatment response and outcome (304, 305) . the consort (306) and grade (307) systems, while useful in evaluating the quality of a randomized trial, unfortunately lack a position on two fundamental elements of a trial design, namely the disease pathophysiology and the pharmacological principles applicable to the investigated drug. unfortunately, lack of these specific reference points has generated misinterpretation of the literature, fueling a non-sensical controversy that clearly is not serving the patient (308) . based on this updated pathophysiological understanding, we offer a few observations and make recommendations for future research. early initiation of treatment, before homeostatic corrections reach exhaustion, is critical and should be directed at approaching maximal saturation of the glucocorticoid receptor (∼100 mg of methylprednisolone equivalent) (309) . an adequate initial loading bolus is necessary to achieve prompt elevation in plasma levels and to assure higher grα saturation in the cytoplasm and on the cell membrane for genomic and non-genomic actions, respectively. in human monocytic cells activated with graded concentrations of lps and then exposed to graded concentrations of methylprednisolone (figure 7) , reduction in inflammatory cytokine transcription was initially modest, then-after reaching an inflection point-followed by a rapid reduction, likely related to achieving maximal drug receptor saturation and adequate time for a measurable effect (102) . to achieve optimal results, the initial loading bolus should be followed by an infusion (daily dose over 24 h) to rapidly achieve a steady state. in patients with septic shock, graded concentrations of lps were followed by progressively higher inflammatory cytokine transcription (for tnf-α: 185, 318, 481, and 566, respectively). these cells were then exposed to graded concentrations of methylprednisolone [(µg/ml): 50, 100, 150, 200, 250] for 6 h followed by repeated measurement of inflammatory cytokine expression (see below). the steady state mrna levels of tnf-α, il-1β, or il-6 in lps-activated cells were reduced by treatment with methylprednisolone in a concentration-dependent manner. the effective dose of methylprednisolone was 175 mg, a value that appeared to be independent of the priming level of lps and type of mrna measured (102) . modified with permission from meduri et al. (102) . hydrocortisone administered as an infusion vs. an intermittent bolus was associated with more rapid resolution of shock (310) , and fewer hyperglycemic episodes (311, 312) . in general, synthetic glucocorticoids are more potent immunoregulators than is cortisol, because they are not subject to endogenous clearance and inhibitors of cortisol activity, including 11βhsd inactivation. moreover, synthetic glucocorticoids bind the glucocorticoid receptors with higher affinity and remain longer in the cell nucleus, while they bind to mineralocorticoid receptors with lower affinity than do endogenous glucocorticoids, thereby minimizing mineralocorticoid-related side effects (313) . pharmacokinetics and pharmacodynamics of systemically administered glucocorticoids are reviewed in reference (314) . hydrocortisone and methylprednisolone are the two glucocorticoids most often investigated in critical care rcts (315) . in the past, different exogenous glucocorticoids were thought to be qualitatively indistinguishable from each other because they act via the same glucocorticoid receptor, however, qualitative differences have been recently discovered, and one glucocorticoid cannot be simply replaced by another (314) . while hydrocortisone was initially chosen as the drug of choice for adrenal replacement, methylprednisolone may actually offer unique advantages over hydrocortisone as follows: (i) greater affinity for the glucocorticoid receptor (316); (ii) higher penetration in lung tissue (important for ards or pneumonia), and with longer residence time (317-319), (iii) higher potency of genomic activity especially nf-κb inhibitory activity (320) ; and (iv) higher potency of non-genomic activity (321) . grα binding affinity, expressed as relative receptor affinity (rra), correlates with glucocorticoid potency. the log rras for selected glucocorticoids are 0.95, 1.62, and 2.0 for hydrocortisone, methylprednisolone, and dexamethasone, respectively (316) . a comparison study between these three types of glucocorticoids is needed. the suggested mode of administration for septic shock [hydrocortisone <400 mg/day for >3 days (315), or hydrocortisone 50 mg qid for 7 days without tapering] is based in part on an outdated pathophysiological model and a misconception about the risk associated with longer duration of treatment (small) and discontinuation without tapering (high). there is some evidence that a treatment duration of 3-7 days directed at reducing acuity of illness (transient reduction in systemic inflammation) might shortchange the full beneficial effects of glucocorticoid therapy (322) . the impact of a longer duration of treatment on medium-and long-term mortality, as observed in rtcs of patients with pneumocystis jiroveci pneumonia (323), needs to be investigated. while glucocorticoids have an important role in supporting homeostatic corrections, this is achieved at the expense of reversible suppression of the hpa axis. in addition, the risk of glucocorticoid treatment-associated adrenal suppression in critically ill patients with dysregulated systemic inflammation is underappreciated. it has been shown that neither the total or the highest dose, nor the duration of glucocorticoid treatment is a significant predictor of hpa axis recovery (324) . in the recent "reduction in the use of corticosteroids in exacerbated copd trial" that evaluated prednisone 40 mg daily for 5 or 14 days, adrenal suppression was detected at hospital discharge and at 30 days in 38 and 9% of patients, respectively; no differences were detected between 5 or 14 days of glucocorticoid exposure (325) . similarly to the experimental literature (326, 327) , critical care rcts have shown that abrupt glucocorticoid discontinuation after a 3-to-14 days treatment was rapidly followed by a reconstituted inflammatory response with a clinical relapse in approximately one-third of the patients (233, 322, 328, 329) , and increased mortality (329) . in the lasrs trial (329) , discontinuation of study drug 48 h postextubation was associated with clinical relapse in one-quarter of methylprednisolone-treated patients. these patients were rapidly returned to mechanical ventilation (mv) without reinstitution of study treatment, fared poorly, required additional days of mv and had a 9-fold increased risk of 60-day mortality (p = 0.001) in comparison to patients that did not return to mv (330) . gradual tapering is necessary to preserve the disease improvement achieved during glucocorticoid administration, to sustain continuous resolution and restoration of tissue homeostasis, to achieve gradual recovery of the suppressed hpa axis, to forestall disease relapse from reconstituted systemic inflammation, and finally to comply with the food and drug administration package insert warnings (reference id: 3032293) (331) . with rapidly expanding knowledge, appreciation of how homeostatic corrections work and how they evolved provides a conceptual framework to understand and appreciate the complex pathobiology of critical illness. we have reviewed emerging literature clearly placing the activated grα at the center of the homeostatic corrections in the general adaptation to critical illness. future research directions should include a reassessment of the pharmacological principles that guide glucocorticoid treatment in critical illness and to devise co-interventions to improve cellular responsiveness to glucocorticoids by correcting conditions associated with a reduction in grα and mitochondrial concentration and function. in addition to the previously used sources (17), we searched the google scholar and pubmed databases, employing the following keywords: "glucocorticoid, " "corticosteroid, " "glucocorticoid receptor, " "stress response, " "acute phase response, " "regulation, " "resolution, " "critical illness related corticosteroid insufficiency, " "treatment, " "systemic inflammation, " "dysregulated" systemic inflammation, " "nuclear factor kappa b, " "evolution, " "endothelium, " "mitochondria, " "reactive oxygen species, " ascorbic acid, thiamine, vitamin d, melatonin, "acute, " "longterm, " chronic, " "homeostasis, " "allostasis, " "cacostasis, " and terms related to critical illness, sepsis, septic shock, acute respiratory distress syndrome, "cardiac events." manual searching of articles, including reference lists of cited publications, was also performed to avoid omissions. gm conceived and initiated the article and wrote the original draft. gc contributed to the conception and worked on successive drafts. this material was the result of work supported with the resources and use of facilities at the memphis va medical center. funding for the respective trials was disclosed in the original publications. linking cellular stress responses to systemic homeostasis the concept of allostasis in biology and biomedicine endocrine changes in critical illness evolutionary origins and functions of the stress response 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corticosteroids as adjunctive therapy for severe pneumocystis carinii pneumonia in the acquired immunodeficiency syndrome. a double-blind, placebo-controlled trial efficacy and safety of corticosteroids for persistent acute respiratory distress syndrome an exploratory reanalysis of the randomized trial on efficacy of corticosteroids as rescue therapy for the late phase of acute respiratory distress syndrome available online at: www key: cord-332533-iqe6sdq2 authors: grant, william b.; lahore, henry; mcdonnell, sharon l.; baggerly, carole a.; french, christine b.; aliano, jennifer l.; bhattoa, harjit p. title: evidence that vitamin d supplementation could reduce risk of influenza and covid-19 infections and deaths date: 2020-04-02 journal: nutrients doi: 10.3390/nu12040988 sha: doc_id: 332533 cord_uid: iqe6sdq2 the world is in the grip of the covid-19 pandemic. public health measures that can reduce the risk of infection and death in addition to quarantines are desperately needed. this article reviews the roles of vitamin d in reducing the risk of respiratory tract infections, knowledge about the epidemiology of influenza and covid-19, and how vitamin d supplementation might be a useful measure to reduce risk. through several mechanisms, vitamin d can reduce risk of infections. those mechanisms include inducing cathelicidins and defensins that can lower viral replication rates and reducing concentrations of pro-inflammatory cytokines that produce the inflammation that injures the lining of the lungs, leading to pneumonia, as well as increasing concentrations of anti-inflammatory cytokines. several observational studies and clinical trials reported that vitamin d supplementation reduced the risk of influenza, whereas others did not. evidence supporting the role of vitamin d in reducing risk of covid-19 includes that the outbreak occurred in winter, a time when 25-hydroxyvitamin d (25(oh)d) concentrations are lowest; that the number of cases in the southern hemisphere near the end of summer are low; that vitamin d deficiency has been found to contribute to acute respiratory distress syndrome; and that case-fatality rates increase with age and with chronic disease comorbidity, both of which are associated with lower 25(oh)d concentration. to reduce the risk of infection, it is recommended that people at risk of influenza and/or covid-19 consider taking 10,000 iu/d of vitamin d(3) for a few weeks to rapidly raise 25(oh)d concentrations, followed by 5000 iu/d. the goal should be to raise 25(oh)d concentrations above 40–60 ng/ml (100–150 nmol/l). for treatment of people who become infected with covid-19, higher vitamin d(3) doses might be useful. randomized controlled trials and large population studies should be conducted to evaluate these recommendations. the world is now experiencing its third major epidemic of coronavirus (cov) infections. a new cov infection epidemic began in wuhan, hubei, china, in late 2019, originally called 2019-ncov [1] the general metabolism and actions of vitamin d are well known [7] . vitamin d 3 is produced in the skin through the action of uvb radiation reaching 7-dehydrocholesterol in the skin, followed by a thermal reaction. that vitamin d 3 or oral vitamin d is converted to 25(oh)d in the liver and then to the hormonal metabolite, 1,25(oh) 2 d (calcitriol), in the kidneys or other organs as needed. most of vitamin d's effect arises from calcitriol entering the nuclear vitamin d receptor, a dna binding protein that interacts directly with regulatory sequences near target genes and that recruits chromatin active complexes that participate genetically and epigenetically in modifying transcriptional output [8] . a well-known function of calcitriol is to help regulate serum calcium concentrations, which it does in a feedback loop with parathyroid hormone (pth), which itself has many important functions in the body [7] . several reviews consider the ways in which vitamin d reduces the risk of viral infections [9] [10] [11] [12] [13] [14] [15] [16] [17] . vitamin d has many mechanisms by which it reduces the risk of microbial infection and death. a recent review regarding the role of vitamin d in reducing the risk of the common cold grouped those mechanisms into three categories: physical barrier, cellular natural immunity, and adaptive immunity [16] . vitamin d helps maintain tight junctions, gap junctions, and adherens junctions (e.g., by e-cadherin) [18] . several articles discussed how viruses disturb junction integrity, increasing infection by the virus and other microorganisms [19] [20] [21] . vitamin d enhances cellular innate immunity partly through the induction of antimicrobial peptides, including human cathelicidin, ll-37, by 1,25-dihdroxyvitamin d [22, 23] , and defensins [24] . cathelicidins exhibit direct antimicrobial activities against a spectrum of microbes, including gram-positive and gram-negative bacteria, enveloped and nonenveloped viruses, and fungi [25] . those host-derived peptides kill the invading pathogens by perturbing their cell membranes and can neutralize the biological activities of endotoxins [26] . they have many more important functions, as described therein. in a mouse model, ll-37 reduced influenza a virus replication [27] . in another laboratory study, 1,25(oh) 2 d reduced the replication of rotavirus both in vitro and in vivo by another process [28] . a clinical trial reported that supplementation with 4000 iu/d of vitamin d decreased dengue virus infection [29] . vitamin d also enhances cellular immunity, in part by reducing the cytokine storm induced by the innate immune system. the innate immune system generates both pro-inflammatory and anti-inflammatory cytokines in response to viral and bacterial infections, as observed in covid-19 patients [30] . vitamin d can reduce the production of pro-inflammatory th1 cytokines, such as tumor necrosis factor α and interferon γ [31] . administering vitamin d reduces the expression of pro-inflammatory cytokines and increases the expression of anti-inflammatory cytokines by macrophages ( [17] and references therein). vitamin d is a modulator of adaptive immunity [16, 32] ; 1,25(oh) 2 d 3 suppresses responses mediated by the t helper cell type 1 (th1), by primarily repressing production of inflammatory cytokines il-2 and interferon gamma (infγ) [33] . additionally, 1,25(oh) 2 d 3 promotes cytokine production by the t helper type 2 (th2) cells, which helps enhance the indirect suppression of th1 cells by complementing this with actions mediated by a multitude of cell types [34] . furthermore, 1,25(oh) 2 d 3 promotes induction of the t regulatory cells, thereby inhibiting inflammatory processes [35] . serum 25(oh)d concentrations tend to decrease with age [36] , which may be important for covid-19 because case-fatality rates (cfrs) increase with age [37] . reasons include less time spent in the sun and reduced production of vitamin d as a result of lower levels of 7-dehydrocholesterol in the skin [38] . in addition, some pharmaceutical drugs reduce serum 25(oh)d concentrations by activating the pregnane-x receptor [39] . such drugs include antiepileptics, antineoplastics, antibiotics, anti-inflammatory agents, antihypertensives, antiretrovirals, endocrine drugs, and some herbal medicines. pharmaceutical drug use typically increases with age. vitamin d supplementation also enhances the expression of genes related to antioxidation (glutathione reductase and glutamate-cysteine ligase modifier subunit) [40] . the increased glutathione production spares the use of ascorbic acid (vitamin c), which has antimicrobial activities [41, 42] , and has been proposed to prevent and treat covid-19 [43] . moreover, a former director of the center for disease control and prevention, dr. tom frieden, proposed using vitamin d to combat the covid-19 pandemic on 23 march 2020 (https://www.foxnews.com/opinion/former-cdc-chief-tomfrieden-coronavirus-risk-may-be-reduced-with-vitamin-d). influenza virus affects the respiratory tract by direct viral infection or by damage to the immune system response. the proximate cause of death is usually from the ensuing pneumonia. patients who develop pneumonia are more likely to be < 5 years old, > 65 years old, white, and nursing home residents, to have chronic lung or heart disease and a history of smoking, and to be immunocompromised [44] . seasonal influenza infections generally peak in winter [45] . cannell et al. hypothesized that the winter peak was due in part to the conjunction with the season when solar uvb doses, and thus 25(oh)d concentrations, are lowest in most mid-and high-latitude countries [46] , extended in [47] . mean serum 25(oh)d concentrations in north and central regions of the united states are near 21 ng/ml in winter and 28 ng/ml in summer, whereas in the south region, they are near 24 ng/ml in winter and 28 ng/ml in summer [48] . in addition, the winter peak of influenza also coincides with weather conditions of low temperature and relative humidity that allow the influenza virus to survive longer outside the body than under warmer conditions [49] [50] [51] . ecological studies suggest that raising 25(oh)d concentrations through vitamin d supplementation in winter would reduce the risk of developing influenza. table 1 presents results from randomized controlled trials (rcts) investigating how vitamin d supplementation affects risk of influenza. the rcts included confirmed that the respiratory tract infection was indeed derived from influenza. only two rcts reported beneficial effects: one among schoolchildren in japan [52] , the other among infants in china [53] . an rct in japan that reported no beneficial effect did not measure baseline 25(oh)d concentration [54] and included many participants who had been vaccinated against influenza (m. urashima; private communication). the two most recent rcts included participants with above average mean baseline 25(oh)d concentrations [55, 56] . a comprehensive review of the role of vitamin d and influenza was published in 2018 [15] . it concluded that the evidence of vitamin d's effects on the immune system suggest that vitamin d should reduce the risk of influenza, but that more studies are required to evaluate that possibility. large population studies would also be useful, in which vitamin d supplementation is also related to changes in serum 25(oh)d concentration. note: 95% confidence interval (95% ci); day (d); hazard ratio (hr); inflammatory bowel disease (ibd); months (mos); not available (n/a); relative risk (rr); upper respiratory tract infection (urti); week (wk); years (yrs). an observational study conducted in connecticut on 198 healthy adults in the fall and winter of 2009-2010 examined the relationship between serum 25(oh)d concentration and incidence of acute rtis (artis) [57] . only 17% of people who maintained 25(oh)d >38 ng/ml throughout the study developed artis, whereas 45% of those with 25(oh)d < 38 ng/ml did. concentrations of 38 ng/ml or more were associated with a significant (p < 0.0001) twofold reduction in risk of developing artis and with a marked reduction in the percentage of days ill. eight influenza-like illnesses (ilis) occurred, seven of which were the 2009 h1n1 influenza. the first step in developing a hypothesis is to outline the epidemiological and clinical findings regarding the disease of interest and their relationship with 25(oh)d concentrations. from the recent journal literature, it is known that covid-19 infection is associated with the increased production of pro-inflammatory cytokines [58] , c-reactive protein [30] , increased risk of pneumonia [58] , sepsis [59] , acute respiratory distress syndrome [59] , and heart failure [59] . cfrs in china were 6%-10% for those with cardiovascular disease, chronic respiratory tract disease, diabetes, and hypertension [37] . two regions hard hit by covid-19 are regions of high air pollution in china [60] and northern italy [61] . the possible roles of vitamin d for the clinical and epidemiological characteristics of diseases associated with the increased risk of covid-19 cfr are given in table 2 . most of the beneficial effects of vitamin d given in table 2 are from observational studies of disease incidence or prevalence with respect to serum 25(oh)d concentrations. rcts comparing outcomes for participants treated or given a placebo are preferred to establish causality related to health outcomes. however, most vitamin d rcts have not reported that vitamin d supplementation reduced the risk of disease [62, 63] . reasons for the lack of agreement between observational studies and rcts seems to be due to several factors, including enrolling participants with relatively high 25(oh)d concentrations and using low vitamin d doses and not measuring baseline and achieved 25(oh)d concentrations. previous studies proposed that rcts of nutrients such as vitamin d be based on nutrient status, such as 25(oh)d concentration, seeking to enroll participants with low values, supplementing them with enough agent to raise the concentration to values associated with good health, and measuring achieved concentrations as well as cofactors such as vitamin c, omega-3 fatty acids, and magnesium [64, 65] ,. two recently completed rcts reported significantly reduced incidence in the secondary analyses for cancer [66] and diabetes mellitus [67] . table 2 . how vitamin d is related to the clinical and epidemiological findings for incidence and case-fatality rates. clinical severe cases associated with pneumonia inverse correlation for cap [68, 69] increased production of pro-inflammatory cytokines such as il-6 inverse correlation [70, 71] increased crp inverse correlation [72, 73] increased risk of sepsis inverse correlation [74, 75] risk of ards inverse correlation [76, 77] risk of heart failure inverse correlation [78, 79] risk of diabetes mellitus inverse correlation [67, 80] epidemiological began in december 2019 in china, spread mainly to northern midlatitude countries low 25(oh)d values in winter [48, 81] males have higher incidence and much higher cfrs than females smoking reduces 25(oh)d [82] cfr increases with age chronic disease rates increase with age; vitamin d plays a role in reducing risk of chronic diseases [83] higher cfr for diabetics diabetics may have lower 25(oh)d [84] higher cfr for diabetics lower 25(oh)d associated with increased risk of incidence [85] higher cfr for hypertension lower 25(oh)d may be associated with increased risk of incidence [86] higher cfr for cardiovascular disease lower 25(oh)d associated with increased risk of incidence and death [87] higher cfr for chronic respiratory disease for copd patients, 25(oh)d inversely correlated with risk, severity, and exacerbation [88] found at higher rates in regions with elevated air pollution air pollution associated with lower 25(oh)d concentrations [89] note: 25-hydroxyvitamin d ((25(oh)d); acute respiratory distress syndrome (ards); community-acquired pneumonia (cap); case-fatality rate (cfr); interleukin 6 (il-6); chronic obstructive pulmonary disease (copd); c-reactive protein (crp); vitamin d deficiency (vdd). table 3 lists some findings for vitamin d supplementation in reducing the clinical effects of covid-19 infection found from treating other diseases. treatment of cap with vitamin d did not significantly result in complete resolution. baseline 25(oh)d was 20 ng/ml. achieved 25(oh)d in the treatment arm was 40 ng/ml. [90] increased production of pro-inflammatory cytokines such as il-6 reduces concentration of il-6 [11] increased crp reduces crp in diabetic patients [91] increased risk of sepsis no reduction in mortality rate found for adults with sepsis supplemented with vitamin d. most trials included participants with 25(oh)d <20 ng/ml; vitamin d 3 doses between 250 and 600 thousand iu. [92] risk of ards vitamin d deficiency contributes to development of ards [77, 93] acute respiratory distress syndrome (ards); community-acquired pneumonia (cap); case-fatality rate (cfr); interleukin 6 (il-6); chronic obstructive pulmonary disease (copd); c-reactive protein (crp); vitamin d deficiency (vdd). a possible reason for the monotonic increase in cfr with increasing age could be that the presence of chronic diseases increases with age. for example, the global prevalence of diabetes mellitus increases from about 1% below the age of 20 years, to~10% at 45 years and to 19% at 65 years, decreasing to 14% by 95 years [94] . invasive lung cancer incidence rates for females in the united states in 2015 increased from 1.1/100,000 for those aged 30-34 years, to 51.0/100,000 for those aged 50-54 years, 204.1/100,000 for those aged 65-79 years, and 347.3 for those aged 75-79 years [95] . several studies report that people with chronic diseases have lower 25(oh)d concentrations than healthy people. a study in italy reported that male chronic obstructive pulmonary disease patients had mean 25(oh)d concentrations of 16 (95% ci, 13-18) ng/ml, whereas female patients had concentrations of 13 (95% ci, 11-15) ng/ml [96] . a study in south korea reported that community-acquired pneumonia (cap) patients had a mean 25(oh)d concentration at admission of 14 ± 8 ng/ml [97] . a study in iran reported that hypertensive patients had lower 25(oh)d concentrations than control subjects: males, 13 ± 11 vs. 21 ± 11 ng/ml; females, 13 ± 10 vs. 20 ± 11 ng/ml [98] . another factor that affects immune response with age is reduced 1,25-dihydroxyvitamin d (1,25(oh) 2 d, or calcitriol), the active vitamin d metabolite, with increased age. parathyroid hormone (pth) concentration increases with age. a u.s. study was based on 312,962 paired serum pth and 25(oh)d concentration measurements from july 2010 to june 2011. for participants with 20-ng/ml 25(oh)d concentration, pth increased from 27 pg/ml for those <20 years to 54 pg/ml for those >60 years [99] . serum calcitriol concentrations are inversely related to pth concentrations. in a study conducted in norway on patients with a mean age of 50 (sd, 21) years, calcitriol decreased from 140 pmol/l for those aged 20-39 years to 98 pmol/l for those >80 years despite an increase in serum 25(oh)d from 24 ng/ml for those 20-39 years to 27 ng/ml for those >80 years [100] . the seasonality of many viral infections is associated with low 25(oh)d concentrations, as a result of low uvb doses owing to the winter in temperate climates and the rainy season in tropical climates-such as respiratory syncytial virus (rsv) infection [101, 102] ,. this is the case for influenza [45, 46] , and sars-cov [103] . however, mers showed a peak in the april-june quarter [104] , probably affected by both hajj pilgrims gathering and the fact that 25(oh)d concentrations show little seasonal variation in the middle east [105] . in the tropics, seasonality is related more to rainy periods (low uvb doses), for example, for influenza [106] . considerable indirect evidence is inferred from effects found for other enveloped viruses. table 4 presents the findings from various studies. table 4 . findings regarding the associations and effects of vitamin d on enveloped viral infections. dengue vitamin d mechanisms discussed [107] dengue inverse association between 25(oh)d concentration and progression of disease state [108] dengue vitamin d supplementation trial with 1000 and 4000 iu/d. 4000 iu/d resulted in higher resistance to denv-2 infection. mddcs from those supplemented with 4000 iu/d showed decreased mrna expression of tlr3, 7, and 9; downregulation of il-12/il-8 production; and increased il-10 secretion in response to denv-2 infection [29] hepatitis c 1,25-hydroxyvitamin-d3-24-hydroxylase, encoded by cyp24a1 gene, is a key enzyme that neutralizes 1,25(oh) 2 d. this study found that alleles of cyp24a1 had different effects on risk of chronic hepatitis c infection. [109] chb 25(oh)d concentrations were lower in chb patients than that of healthy controls and inversely correlated with hbv viral loads [110] kshv found that cathelicidin significantly reduced ksvh by disrupting the viral envelope. [111] hiv-1 review of 29 clinical studies of vitamin d supplementation showed there was a decrease in inflammation. in 3 of 7 studies, cd4+ t cell count increased, but effect on viral load was inconclusive since most patients were on cart. [112] in a lung epithelial cell study, calcitriol treatment prior to and post infection with h9n2 influenza significantly decreased expression of the influenza m gene, il-6, and ifn-β in a549 cells, but did not affect virus replication. [113] rsv demonstrated that the human cathelicidin ll-37 has effective antiviral activity against rsv in vitro and prevented virus-induced cell death in epithelial cultures, [114] rsv performed a laboratory study that identified the mechanism by which vitamin d reduced risk of rsv. [28] rsv found that the t-allele of the vitamin d receptor has a lower prevalence in african populations and runs parallel to the lower incidence of rsv-associated severe alri in african children, 1 year. [115] rotaviral diarrhea found serum 25(oh)d <20 ng/ml associated with an odds ratio of 6.3 (95% ci, 3.6 to 10.9) for rotaviral diarrhea [116] note: acute respiratory tract infection (alri); combination antiretroviral therapy (cart); chronic hepatitis b (chb); dengue virus-2 (denv-2). human immunodeficiency virus 1 (hiv-1); kaposi's sarcoma-associated herpesvirus (kshv); monocyte-derived dendritic cells (mddcs); respiratory syncytial virus (rsv). one way that covs injure the lung epithelial cells and facilitate pneumonia is through increased production of th1-type cytokines as part of the innate immune response to viral infections, giving rise to the cytokine storm. a laboratory cell study reported that interferon γ is responsible for acute lung injury during the late phase of the sars-cov pathology [117] . pro-inflammatory cytokine storms from cov infections have resulted in the most severe cases for sars-cov [118] and mers-cov [119] . however, covid-19 infection also initiated increased secretion of the th2 cytokines (e.g., interleukins 4 and 10) that suppress inflammation, which differs from sars-cov infection [30] . an example of the role of vitamin d in reducing the risk of death from pandemic respiratory tract infections is found in a study of cfrs resulting from the 1918-1919 influenza pandemic in the united states [120] . the u.s. public health service conducted door-to-door surveys of 12 communities from new haven, connecticut, to san francisco, california, to ascertain incidence and cfrs. the canvasses were made as soon as possible after the autumn 1918 wave of the epidemic subsided in each locality. a total of 146,203 people, 42,920 cases, and 730 deaths were found. as shown in their table 25 , fatality rates averaged 1.70 per 100 influenza cases but averaged 25.5 per 100 cases of pneumonia. the percentage of influenza complicated by pneumonia was 6.8%. the pneumonia cfr (excluding charles county, md, because of inconsistencies in recording cause of death) was 28.8 per 100 for whites and 39.8 per 100 for "coloreds". as shown in table 23 , "coloreds" in the southeastern states had between a 27% and 80% higher rate of pneumonia compared to whites. as discussed in an ecological study using those cfr data, communities in the southwest had lower cfr than those in the northeast because of higher summertime and wintertime solar uvb doses [121] . previous work suggested that higher uvb doses were associated with higher 25(oh)d concentrations, leading to reductions in the cytokine storm and the killing of bacteria and viruses that participate in pneumonia. african americans had much higher mortality rates than white americans for the period 1900-1948 [122] . the reasons cfrs were higher for "coloreds" than whites may include that they have higher rates of chronic diseases, are more likely to live in regions impacted by air pollution, and that with darker skin pigmentation, blacks have lower 25(oh)d concentrations. a clinical trial involving postmenopausal women living on long island, ny with mean baseline 25(oh)d concentration 19 ± 8 ng/ml found that supplementation with 2000 iu/d resulted in significantly fewer upper respiratory tract infections, including influenza, than a placebo or supplementation with 800 iu/d [123] . see, also, references in [11] . an analysis of serum 25(oh)d concentrations by race for 2001-2004 indicated mean 25(oh)d concentrations for people over 40 years: non-hispanic whites,~25-26 ng/ml; non-hispanic blacks, 14-17 ng/ml; mexican-americans, 18-22 ng/ml [124] . a reason proposed for the higher mortality rates in some communities during the 1918-1919 influenza pandemic was that they were near to coal-fired electricity generating plants [125] . recent studies have confirmed that air pollution, from combustion sources, increases the risk of influenza [126, 127] . the highest concentration of these plants is in the northeast, where solar uvb doses are lowest. [93] . in a follow-on pilot trial involving 30 mechanically ventilated critically ill patients, 500,000 iu of vitamin d 3 supplementation significantly increased hemoglobin concentrations and lowered hepcidin concentrations, improving iron metabolism and the blood's ability to transport oxygen [128] . hospitals are a source of rtis for both patients and medical personnel. for example, during the sars-cov epidemic, a woman returned to toronto from hong kong with sars-cov in 2003 and went to a hospital. the disease was transmitted to other people, leading to an outbreak among 257 people in several greater toronto area hospitals [129] . during the 2014-2015 influenza season, 36% of health care workers in a german hospital developed influenza infection [130] . working in a hospital dealing with covid-19 patients is associated with increased risk of covid-19 infection. for example, 40 of 138 hospitalized covid-19 patients in wuhan in the zhongnan hospital from 1 to 28 january were medical staff, and 17 more were infected while in the hospital [58] . it was announced on february 14, 2020, that more than 1700 chinese health workers were infected by covid-19 and six had died (https://www.huffpost.com/entry/chinese-health-workers-infected-by virus_n_5e46a0fec5b64d860fc97c1b). vitamin d supplementation to raise serum 25(oh)d concentrations can help reduce hospitalassociated infections [131] . concentrations of at least 40-50 ng/ml (100-125 nmol/l) are indicated on the basis of observational studies [132, 133] . during the covid-19 epidemic, all people in the hospital, including patients and staff, should take vitamin d supplements to raise 25(oh)d concentrations as an important step in preventing infection and spread. trials on that hypothesis would be worth conducting. the data reviewed here supports the role of higher 25(oh)d concentrations in reducing risk of infection and death from artis, including those from influenza, cov, and pneumonia. the peak season for artis is generally when 25(oh)d concentrations are lowest. thus, vitamin d 3 supplementation should be started or increased several months before winter to raise 25(oh)d concentrations to the range necessary to prevent artis. studies reviewed here generally reported that 25(oh)d concentrations of 20-30 ng/ml reduced the risk of artis [134] . one reason for that result may be that the studies included few participants with higher 25(oh)d concentrations. however, one observational study reported that 38 ng/ml was the appropriate concentration to reduce the risk of cap [57] . although the degree of protection generally increases as 25(oh)d concentration increases, the optimal range appears to be in the range of 40-60 ng/ml (100-150 nmol/l). to achieve those levels, approximately half the population could take at least 2000-5000 iu/d of vitamin d 3 [135] . various loading doses have been studied for achieving a 25(oh)d concentration of 30 ng/ml. for example, one study used a weekly or fortnightly dose totaling 100,000-200,000 iu over 8 weeks (1800 or 3600 iu/d) [136] . however, to achieve 40-60 ng/ml would take higher loading doses. a trial involving canadian breast cancer patients with bone metastases treated with bisphosphonates but without comorbid conditions reported that doses of 10,000 iu/d of vitamin d 3 over a four-month period showed no adverse effects, but did unmask two cases of primary hyperparathyroidism [137] . a study involving 33 participants, including seven taking 4000 iu/d of vitamin d 3 and six who took 10,000 iu/d of vitamin d 3 for 8 weeks, reported that 25(oh)d concentrations increased from 20 ± 6 to 39 ± 9 for 4000 iu/d and from 19 ± 4 to 67 ± 3 for 10,000 iu/d and improved gut microbiota with no adverse effects [138] . thus, from the literature, it is reasonable to suggest taking 10,000 iu/d for a month, which is effective in rapidly increasing circulating levels of 25(oh)d into the preferred range of 40-60 ng/ml. to maintain that level after that first month, the dose can be decreased to 5000 iu/d [135, 139, 140] . when high doses of vitamin d are taken, calcium supplementation should not be high to reduce risk of hypercalcemia. a recent review suggested using vitamin d loading doses of 200,000-300,000 iu in 50,000-iu capsules to reduce the risk and severity of covid-19 [43] . the efficacy and safety of high-dose vitamin d supplementation has been demonstrated in a psychiatric hospital in cincinnati, ohio [141] . the age range was from 18 to 90 years. half of the patients were black, and nearly half were white. all patients entering since 2011 were offered supplementation of 5000 or 10,000 iu/d vitamin d 3 . for 36 patients who received 5000 iu/d for 12 months or longer, mean serum 25(oh)d concentration rose from 24 to 68 ng/ml, whereas for the 78 patients who received 10,000 iu/d, mean concentrations increased from 25 to 96 ng/ml. no cases of vitamin d-induced hypercalcemia were reported. this article includes a brief review of other high-dose vitamin d studies, including the fact that vitamin d doses of 60,000-600,000 iu/d were found to treat and control such diseases as asthma, rheumatoid arthritis, rickets, and tuberculosis in the 1930s and 1940s. those doses are much higher than the 10,000-25,000 iu/d of vitamin d 3 that can be made from solar uvb exposure [142] . however, after reports of hypercalcemia associated with use of supra-physiological doses of vitamin d surfaced, e.g., [143] , high-dose vitamin d supplementation fell out of favor. a recent article on a high-dose vitamin d supplementation trial in new zealand involving 5110 participants reported that, over a median of 3.3 years, monthly supplementation with 100,000 iu of vitamin d 3 did not affect the incidence rate of kidney stone events or hypercalcemia [144] . unfortunately, most countries do not have guidelines supporting vitamin d supplementation doses and desirable serum 25(oh)d concentrations that would deal with wintertime rtis. guidelines for many countries consider 20 ng/ml (50 nmol/l) adequate. according to the statement from the european society for clinical and economic aspects of osteoporosis, osteoarthritis, and musculoskeletal diseases, "attainment of serum 25-hydroxyvitamin d levels well above the threshold desired for bone health cannot be recommended based on current evidence, since safety has yet to be confirmed" [145] . this statement, published in 2017, is no longer correct since a number of vitamin d supplementation studies have reported that long-term vitamin d supplementation has health benefits without adverse health effects, e.g., 2000 iu/d for cancer risk reduction [66, 146] and 4000 iu/d for reduced progression from prediabetes to diabetes [67] . a recent review on the status of vitamin d deficiency worldwide stated that because of inadequate evidence from clinical trials, "a 25(oh)d level of >50 nmol/l or 20 ng/ml is, therefore, the primary treatment goal, although some data suggest a benefit for a higher threshold" [147] . a companion article in the same issue of the journal stated, "although 20 ng/ml seems adequate to reduce risk of skeletal problems and artis, concentrations above 30 ng/ml have been associated with reduced risk of cancer, type 2 diabetes mellitus, and adverse pregnancy and birth outcomes" [148] . however, on the basis of the findings in several studies discussed here, as well as recommendations for breast and colorectal cancer prevention [149] , the desirable concentration should be at least 40-60 ng/ml. the u.s. institute of medicine issued vitamin d and calcium guidelines in 2011 [150] . the institute recommended vitamin d supplementation of 600 iu/d for people younger than 70 years, 800 iu/d for those older than 70 years, and a serum 25(oh)d concentration of 20 ng/ml (50 nmol/l) or higher. that recommendation was based on the effects of vitamin d for bone health. the institute recognized that no studies had reported adverse effects of supplementation with less than 10,000 iu/d of vitamin d, but set the upper intake level at 4000 iu/d, partly out of concerns stemming from observational studies that found u-shaped 25(oh)d concentration-health outcome relationships. however, later investigation determined that most reports of j-or u-shaped relationships were from observational studies that did not measure serum 25(oh)d concentrations and that the likely reason for those relationships was a result of enrolling some participants who had started taking vitamin d supplements shortly before enrolling [151] . moreover, in 2011, the endocrine society recommended supplementation of 1000-4000 iu/d of vitamin d and a serum 25(oh)d concentration of 30 ng/ml or higher [152] . those guidelines were for patients. it appears that anyone with chronic disease should be considered in that category. the u.s. institute of medicine noted that no adverse effects of vitamin d supplementation had been reported for daily doses <10,000 iu/d [150] . measuring serum 25(oh)d concentration would be useful to determine baseline and achieved 25(oh)d concentrations. a recent article recommended testing for groups of people who were likely to have low concentrations and could benefit from higher concentrations, such as pregnant women, the obese, people with chronic diseases, and the elderly [148] . part of the rationale for testing was to increase awareness of actual 25(oh)d concentrations and the benefits of higher concentrations. in addition, increases in 25(oh)d concentration with respect to vitamin d supplementation depend on various personal factors, including genetics, digestive system health, weight, and baseline 25(oh)d concentration. for about half the population, taking 5000 iu/d of vitamin d 3 or 30,000-35,000 iu/wk would raise 25(oh)d concentration to 40 ng/ml. taking 6235-7248 iu/d as proposed to ensure that 97.5% of the population has concentrations >20 ng/ml [153] would not exceed the 10,000-iu/d threshold. vitamin d supplementation is required for many individuals to reach 25(oh)d concentrations above 30 ng/ml, especially in winter [154] . however, vitamin d fortification of basic foods such as dairy and flour products [83, 155] can raise serum 25(oh)d concentrations of those members of various populations with the lowest concentrations by a few ng/ml. doing so can result in reduced risk of artis for individuals with extreme vitamin d deficiency [134, 156] . however, for greater benefits, daily or weekly vitamin d supplementation is recommended [134] , as is the annual determination of serum 25(oh)d concentration for those with health risks [148] . magnesium supplementation is recommended when taking vitamin d supplements. magnesium helps activate vitamin d, which in turn helps regulate calcium and phosphate homeostasis to influence the growth and maintenance of bones. all the enzymes that metabolize vitamin d seem to require magnesium, which acts as a cofactor in the enzymatic reactions in the liver and kidneys [157] . the dose of magnesium should be in the range of 250-500 mg/d, along with twice that dose of calcium. the hypothesis that vitamin d supplementation can reduce the risk of influenza and covid-19 incidence and death should be investigated in trials to determine the appropriate doses, serum 25(oh)d concentrations, and the presence of any safety issues. the rct on vitamin d supplementation for ventilated icu patients conducted in atlanta, georgia, is a good model [93] . a recent review stated: "although contradictory data exist, available evidence indicates that supplementation with multiple micronutrients with immune-supporting roles may modulate immune function and reduce the risk of infection. micronutrients with the strongest evidence for immune support are vitamins c and d and zinc. better design of human clinical studies addressing dosage and combinations of micronutrients in different populations are required to substantiate the benefits of micronutrient supplementation against infection." 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medicine: what clinicians need to know do studies reporting 'u'-shaped serum 25-hydroxyvitamin d-health outcome relationships reflect adverse effects? derm evaluation, treatment, and prevention of vitamin d deficiency: an endocrine society clinical practice guideline optimal vitamin d supplementation doses that minimize the risk for both low and high serum 25-hydroxyvitamin d concentrations in the general population vitamin d supplementation guidelines a review of the potential benefits of increasing vitamin d status in mongolian adults through food fortification and vitamin d supplementation randomized trial of vitamin d supplementation and risk of acute respiratory infection in mongolia role of magnesium in vitamin d activation and function this article is an open access article distributed under the terms and conditions of the creative commons attribution (cc by) license key: cord-321401-w4ne60fn authors: schrumpf, jasmijn a.; van der does, anne m.; hiemstra, pieter s. title: impact of the local inflammatory environment on mucosal vitamin d metabolism and signaling in chronic inflammatory lung diseases date: 2020-07-10 journal: front immunol doi: 10.3389/fimmu.2020.01433 sha: doc_id: 321401 cord_uid: w4ne60fn vitamin d plays an active role in the modulation of innate and adaptive immune responses as well as in the protection against respiratory pathogens. evidence for this immunomodulatory and protective role is derived from observational studies showing an association between vitamin d deficiency, chronic airway diseases and respiratory infections, and is supported by a range of experimental studies using cell culture and animal models. furthermore, recent intervention studies have now shown that vitamin d supplementation reduces exacerbation rates in vitamin d-deficient patients with chronic obstructive pulmonary disease (copd) or asthma and decreases the incidence of acute respiratory tract infections. the active vitamin d metabolite, 1,25-dihydroxy-vitamin d (1,25(oh)(2)d), is known to contribute to the integrity of the mucosal barrier, promote killing of pathogens (via the induction of antimicrobial peptides), and to modulate inflammation and immune responses. these mechanisms may partly explain its protective role against infections and exacerbations in copd and asthma patients. the respiratory mucosa is an important site of local 1,25(oh)(2)d synthesis, degradation and signaling, a process that can be affected by exposure to inflammatory mediators. as a consequence, mucosal inflammation and other disease-associated factors, as observed in e.g., copd and asthma, may modulate the protective actions of 1,25(oh)(2)d. here, we discuss the potential consequences of various disease-associated processes such as inflammation and exposure to pathogens and inhaled toxicants on vitamin d metabolism and local responses to 1,25(oh)(2)d in both immuneand epithelial cells. we furthermore discuss potential consequences of disturbed local levels of 25(oh)d and 1,25(oh)(2)d for chronic lung diseases. additional insight into the relationship between disease-associated mechanisms and local effects of 1,25(oh)(2)d is expected to contribute to the design of future strategies aimed at improving local levels of 1,25(oh)(2)d and signaling in chronic inflammatory lung diseases. vitamin d is a pleiotropic hormone that is well-known for its role in the regulation of calcium and phosphate homeostasis and bone mineralization. the vitamin d receptor (vdr) acts as the receptor for the active form of vitamin d, i.e., 1,25dihydroxy-vitamin d [1, 25(oh) 2 d], and is expressed in nearly all tissues and cell-types and regulates a large number of genes (∼0.8-5% of the total genome) (1, 2) . as a result, vitamin d affects many additional processes including cell proliferation and differentiation, apoptosis, dna repair, ion transport, metabolism, cell adhesion, and oxidative stress responses (1, 3) . vitamin d deficiency [serum 25-hydroxy-vitamin d [25(oh)d] < 50 nmol/l; 25(oh)d is the main circulating form of vitamin d and its levels are used to assess vitamin d status in the clinic (4, 5) affects more than 30% of the children and adults worldwide and is a major cause of bone diseases such as rickets and osteoporosis (6) . increasing evidence has indicated that vitamin d deficiency is also associated with various other diseases such as cancer, cardiovascular disease, alzheimer's disease and muscle myopathy, as well as several immune-related diseases such as type 1 diabetes, multiple sclerosis, inflammatory bowel disease (ibd), psoriasis and chronic inflammatory lung diseases including asthma, cystic fibrosis (cf), and chronic obstructive pulmonary disease (copd) (6) (7) (8) (9) . several studies have now shown that vitamin d deficiency is prevalent in copd patients and inversely correlated with lung function and severity of the disease (8) (9) (10) (11) (12) . it is currently unknown whether vitamin d deficiency is a cause or consequence of copd, since many copd patients have low physical activity levels and spend most time indoors (13) . there are however studies suggesting that low 25(oh)d levels are associated with development of copd, based on observed associations between polymorphisms in the vitamin d binding protein (vdbp), 25(oh)d serum levels and copd severity (8, 10, 11, 14) . in addition, one study in mice showed that maternal vitamin d deficiency can impair lung -development, -structure andfunction in the offspring and suggests that even before birth, maternal 25(oh)d serum levels are important for a healthy lung development (15) . this might be relevant, since associations have been found between lower childhood lung function and development of copd later in life (16) . the link between maternal 25(oh)d status and asthma development is however much clearer, since two recent randomized controlled trials (rcts) have shown that maternal vitamin d supplementation reduces the risk of childhood asthma/recurrent wheeze (17) . this might be explained by the fact that multiple vitamin d-regulated genes are transcriptionally active during alveolar maturation and a number of these genes are differentially expressed in asthma (18) . additionally, this protective effect was linked to the gggenotype of the 17q21 functional snp rs12936231, which is associated with lower expression of ormdl3 and increased sphingolipid metabolism (19) . moreover, maternal circulating 25(oh)d levels affect the gut microbiota and can therefore indirectly modulate immune responses in the lung via the gutlung-axis (20) . also later in life, optimal 25(oh)d levels remain crucial for keeping the lungs healthy. for example, heulens et al. showed that subacute and chronic cigarette smoke (cs) exposure decreased lung function and promoted early signs of emphysema and airway inflammation in vitamin d-deficient mice compared to vitamin d-sufficient animals (21) . similarly in an elastase-induced copd mouse model, topical administration of vitamin d in the lungs counteracted alveolar damage and improved lung function (22) . yet in humans, it is still unclear whether vitamin d status influences copd development and disease progression. taken together, these observations suggest an important role for vitamin d during fetal and childhood lung maturation, and indicate that sufficient 25(oh)d levels might contribute to protection against development of childhood asthma and possibly copd at older age. systemic levels of biologically active 1,25(oh) 2 d are tightly regulated to preserve sufficient levels of calcium (ca 2+ ) and phosphate (po 4 2− ) for optimal bone mineralization, whereas in mucosal tissues locally produced (autocrine) 1,25(oh) 2 d levels and signaling can be elevated or decreased upon exposure to inflammatory mediators, pathogens or inhaled toxicants (6) . this could be important, since the inflamed airway mucosa of patients suffering from chronic inflammatory lung diseases is constantly exposed to these disease-associated factors (8, 23, 24) . impaired local levels of 1,25(oh) 2 d and vdr signaling might have consequences for disease pathogenesis and progression. dysregulated host defenses as found in patients with chronic inflammatory airway diseases include aberrant immune responses, altered microbiome composition, impaired epithelial barrier function, and aberrant secretion of host defense molecules (25) (26) (27) . adequate 1,25(oh) 2 d levels may provide protection against these dysregulated processes by maintaining the integrity of the mucosal barrier and promotion of killing of pathogens (e.g., via the induction of the antimicrobial peptide [amp] hcap18/ll-37) and via the modulation of both innate and adaptive immune responses (7, 28, 29) . in this review, we first discuss the effects of these disease-associated factors on local synthesis and availability of 1,25(oh) 2 d and 1,25(oh) 2 d-induced responses in the lung mucosa. in the second part of the review we will describe the mechanistic links between vitamin d deficiency and the pathogenesis of chronic inflammatory lung diseases such as asthma, cf and copd, and discuss recent evidence related to the protective effects of vitamin d on copd and on copd exacerbations. vitamin d enters the circulation either via food intake (plantbased: vitamin d 2 /animal-based: vitamin d 3 ) or as a result of its synthesis in the skin by uvb radiation. it subsequently binds to the vdbp (30, 31) , after which this complex is transported to the liver where it is converted by vitamin d-25hydroxylases (cyp2ri and cyp27a1) into 25(oh)d. however, recent studies showed that also other cell types such as airway epithelial cells, keratinocytes, intestinal epithelial cells, and monocytes/macrophages express cyp2ri and cyp27a1, and thus are able to (locally) convert vitamin d 3 into 25(oh)d 3 (32, 33) . this inactive 25(oh)d needs to be converted into the active 1,25(oh) 2 d by 25-hydroxyvitamin d-1α-hydroxylase (cyp27b1) in the kidney and in other cells, including several immune-and epithelial cells (34) (35) (36) (37) (38) (39) (40) . 1,25(oh) 2 d regulates expression of several genes by binding the nuclear vdr, which heterodimerizes with the retinoic acid receptor (rxr) to interact with vitamin d response elements (vdres) that are present on the promoter region of these genes (1, 2) . vdr is most abundantly expressed in intestinal enterocytes, pancreatic islets, renal distal tubules and osteoblasts, but is also present at lower levels in most other tissues and several other epithelial-and immune cells (41) (42) (43) (44) (45) . expression of vdr is classically regulated by 1,25(oh) 2 d, growth factors and hormones such as fgf-23 and pth, respectively, circulating calcium levels, bile acids, transcriptional co-activators/repressors, and genetic-and epigenetic modifications, which is tissue specific (46) (47) (48) (49) . 1,25(oh) 2 d regulates its own negative feedback by several mechanisms, including induction of expression of the catabolic enzymes 25-hydroxyvitamin d-24-hydroxylase (cyp24a1) and cyp3a4 (50, 51) . cyp24a1 is expressed in most tissues and converts both 25(oh)d and 1,25(oh) 2 d into 23,25(oh) 2 d or 24,25(oh) 2 d and 1,23,25(oh) 3 d or 1,24,25(oh) 3 d, respectively (dependent on whether cyp24a1 hydroxylates at c-23 or at c-24). these are further converted into metabolites that have been found to be excreted into the bile (summarized in figure 1 ) (50, 52, 56) . cyp3a4 is mainly expressed in the liver and small intestines and contributes to the metabolic clearance of 25(oh)d and 1,25(oh) 2 d by converting 25(oh)d into 4β,25(oh) 2 d, and 1,25(oh) 2 d into frontiers in immunology | www.frontiersin.org 1,23r,25(oh) 2 d or 1,24s,25(oh) 2 d (51). expression of both cyp27b1 and cyp24a1 in the kidneys is tightly regulated to maintain optimal ca 2+ -and po 4 2− levels in the circulation, which are important for bone mineralization (57) . in short, in response to low ca 2+ levels, parathyroid hormone (pth) is secreted by the pituitary glands, which in turn reduces ca 2+ excretion and reabsorption of po 4 2− (57). pth further induces expression of cyp27b1 and represses expression of cyp24a1 in the kidneys (57) . this will increase the levels of 1,25(oh) 2 d in the circulation, which promotes intestinal ca 2+ and po 4 2− absorption (57) . these elevated circulating ca 2+ and po 4 2− levels will subsequently induce expression of fibroblast growth factor 23 (fgf-23) in osteocytes and osteoblasts and impair secretion of parathyroid hormone (pth) by the parathyroid glands (3). in the kidneys, fgf-23 suppresses expression of cyp27b1 and induces expression of cyp24a1, thereby inhibiting the synthesis and promoting degradation of 1,25(oh) 2 d (3). these complex mechanisms that explain how vitamin d and its metabolic enzymes maintain sufficient ca 2+ and po 4 2− levels in the circulation are more extensively discussed by quarles et al. (57) . in summary, it has become increasingly evident that the effects of vitamin d are not limited to homeostasis of ca 2+ and po 4 2− and bone mineralization, because several extra-renal cells such as airway epithelial cells and immune cells express the vdr and are capable of converting circulating 25(oh)d into the active 1,25(oh) 2 d metabolite. local levels and activity of 1,25(oh) 2 d are in part determined by expression of vdr and the equilibrium between the vitamin d metabolic enzymes cyp27b1 and cyp24a1. it is important to realize that mucosal expression of cyp24a1, cyp27b1 and also vdr can be affected by several disease-associated inflammatory mediators, toxicants and pathogens, summarized in table 1 . as a consequence of this, the local availability of 1,25(oh) 2 d and/or vdr signaling in tissues such as the inflamed airways of patients that suffer from chronic inflammatory airway diseases might be reduced. chronic lung diseases are characterized by airway inflammation and impaired respiratory host defense, which is illustrated by the increased susceptibility for respiratory infections and exacerbations (25, 80, 81) . furthermore, exposure to inhaled toxicants such as cigarette smoke and air pollutants are associated with disease pathogenesis and exacerbations in copd, cf and in asthma patients (82) (83) (84) . it would therefore be of great interest to investigate these effects on local 1,25(oh) 2 d levels and on 1,25(oh) 2 d-mediated respiratory host defense in the airway mucosa. studies in airway epithelial cells have shown that exposure to uv-inactivated non-typeable haemophilus influenzae (nthi) increased expression of the coga-1a (colon cancer epithelial cell line) trophoblasts tnf-α; il-1β; il-6 cyp24a1 ↑ macrophages macrophages (derived from thp-1) macrophages (derived from thp-1) t cells t cell activators (anti-cd3/anti-cd28; pha; pma/ionomycin) other hand, in the bronchial cell line beas-2b expression of vdr was decreased after infection with respiratory viruses such as human rhinovirus (hrv) and respiratory syncytial virus (rsv) (58) . collectively, these studies have shown in airway epithelial cells that respiratory viral-and bacterial infections can either promote or impair 1,25(oh) 2 d synthesis and responses. a local airway inflammatory milieu can also exert differential effects on 1,25(oh) 2 d synthesis and signaling, dependent on the type of inflammatory mediators that are predominantly present. we have shown in differentiated primary airway epithelial cells that th2 cytokines such as il-4 and il-13, enhance expression of cyp27b1 and expression of hcap18/ll-37 upon 25(oh)d3 treatment, which suggests that a th2-inflammatory environment, as found in allergic airway inflammation, increases the conversion of 25(oh)d into the active 1,25(oh) 2 d (83, 85) . the observation that levels of both 1,25(oh) 2 d and hcap18/ll-37 were increased in bronchoalveolar lavage (bal) after allergen challenge is in line with this proposed mechanism (86) . this effect of th2 cytokines was in contrast to the effects (chronic) exposures to the proinflammatory cytokines il-1β, tnf-α and il-17a that strongly increased the expression of the 25(oh)d-and 1,25(oh) 2 d-degrading cyp24a1, even in absence of its inducer 1,25(oh) 2 d (61). furthermore, shortterm exposures to tgf-β1, a pleiotropic growth factor which is elevated in the lungs of copd, cf and asthma patients, also increases the expression of cyp24a1 (62) . as a consequence, 1,25(oh) 2 d-mediated expression of the amp hcap18/ll-37 was impaired, which was likely the result of the enhanced degradation of both 25(oh)d and 1,25(oh) 2 d by this enzyme (61, 62) . in addition to pathogens and cytokines, exposure to inhaled toxicants such as cigarette smoke (cs) and particulate matter (pm) may also alter expression or activity of vdr and cyp27b1. studies have demonstrated that cigarette smoking or exposure to cs extract (cse) decreases expression of cyp27b1 and inhibited membrane bound (m)vdr translocation to the cell membrane in airway epithelial cells and a549 cells (an alveolar tumor cell line), respectively (63, 64, 66) . this inhibition reduces the conversion of 25(oh)d to 1,25(oh) 2 d and 1,25(oh) 2 d-mediated gene expression as well as nongenomic actions of 1,25(oh) 2 d-membrane associated, rapid response steroid-binding (marrs)-signaling (63, 64, 66) . this adverse effect of cigarette smoking on the synthesis and effects of 1,25(oh) 2 d in airway epithelial cells was recently confirmed in vivo by vargas buonfiglio et al. who demonstrated that vitamin d supplementation increased antimicrobial activity in apical surface liquid (asl) in the airway of healthy non-smokers, but not in smokers (64) . on the other hand, exposure to pm increases the expression of both cyp27b1 and vdr in airway epithelial cells, thereby possibly promoting the synthesis and effects of 1,25(oh) 2 d (59). it is however important to consider that several retrospective and observational studies have demonstrated that air pollution is an independent risk factor for developing vitamin d deficiency (87) . in conclusion, exposure to cs, tgf-β1 and presence of a proinflammatory milieu appeared to most strongly decrease local presence and signaling of 1,25(oh) 2 d in airway epithelial cells. igm/anti-cd40/il-21) cyp27b1 ↑ vdr ↑(79) whereas, various studies show that exposure to proinflammatory stimuli most likely affects local 25(oh)d and 1,25(oh) 2 dlevels and reduces the effects of 25(oh)d and 1,25(oh) 2 d in (airway) epithelial cells, the opposite appears to be the case for immune cells. in monocytes, macrophages and neutrophils, effects on 1,25(oh) 2 d synthesis and antimicrobial responses upon 25(oh)d treatment were generally enhanced by these proinflammatory stimuli as illustrated by increased expression of both vdr and cyp27b1 (39, 71, (74) (75) (76) (77) . it is therefore tempting to speculate that this apparent increase in antimicrobial responses upon 25(oh)d treatment in immune cells in an inflammatory environment may serve as a second line of defense and compensate for the enhanced epithelial degradation of 25(oh)d and 1,25(oh) 2 d during inflammation. inhaled toxicants may also affect 1,25(oh) 2 d availability and responsiveness of immune cells. this is illustrated by two recent studies studying the effects of cigarette smoke on the human monocyte/macrophage-like cell line thp-1. one study showed that treatment with cigarette smoke extract (cse) increased the expression of vdr without enhancing 1,25(oh) 2 d responses (72), while the other study -that focused on the effects of benzo[a]pyrene (bap) (a component produced by cigarette combustion)-demonstrated that 1,25(oh) 2 dmediated cyp24a1 expression was induced, which was found to further enhance degradation of 1,25(oh) 2 d (73). in summary, proinflammatory stimuli generally increased the effect of 25(oh)d and 1,25(oh) 2 d on immune cells, whereas more studies are needed to fully determine the impact of exposure to cigarette smoke and other inhaled toxicants. whereas, these studies provide evidence that inflammation and inhaled toxicants may affect 25(oh)d and 1,25(oh) 2 d metabolism and responsiveness in epithelial cells and immune cells, it is not clear whether this has an impact on these events in lung tissue of patients with chronic lung diseases. although evidence is limited, we can speculate that levels of 1,25(oh) 2 d and responses are also affected by disease-associated factors in mesenchymal cells that are present in the lung mucosa. one study that showed in a bleomycin fibrosis model and in primary lung mouse fibroblasts that tgf-β1 reduced expression of the vdr might support this assumption (88) . it is currently insufficiently studied whether exposures to disease-associated factors promote or impair levels of 1,25(oh) 2 d and responses in immune-, mesenchymal and epithelial cells combined to give a better reflection of the in vivo situation. interestingly, one study did already show that nasal cyp27b1-and 1,25(oh) 2 d-levels are both reduced in chronic rhinosinusitis (crs) patients with nasal polyps as compared to crs-patients without nasal polyps, whereas no difference was found in circulating 1,25(oh) 2 dlevels (89) . since most other studies were performed in vitro using monocultures of epithelial cells or immune cells, more complex models are needed to delineate this. therefore, animal models or preferably more complex animal-free cell culture models using co-cultures or organs-on-chips models of primary fully differentiated epithelial cells, airway-derived fibroblasts or smooth muscle cells and immune cells could be considered in future studies. after discussing altered 25(oh)d and 1,25(oh) 2 d metabolism and responsiveness in the inflamed airway mucosa, it is important to consider the possible consequences of these inflammation-induced changes in the airway mucosa keeping in mind the pleotropic effects of 1,25(oh) 2 d that were introduced earlier. in several cells, tissues and organs, 1,25(oh) 2 d regulates multiple cellular processes that affect normal and malignant cell growth and differentiation (90, 91) . 1,25(oh) 2 d displays furthermore protective effects on mucosal host defense by maintaining the integrity of the epithelial barrier, inhibition of epithelial-to-mesenchymal transition (emt), stimulating production of amps and modulating both innate-and adaptive immune functions (7, 29, 92) . in addition, 1,25(oh) 2 d maintains both energetic and survival homeostasis in the mucosal epithelium through the modulation of stress and damage responses, including clearance of disturbing and stressful agents (3, 93) (figure 2 ). in chronic inflammatory lung diseases, epithelial barrier function is impaired, and as a consequence the susceptibility toward respiratory infections is increased (94) . there is increasing evidence that 1,25(oh) 2 d promotes epithelial barrier integrity or protects against epithelial barrier destruction. in cells of the bronchial epithelial cell line 16hbe, 1,25(oh) 2 d inhibited csemediated reduction of the epithelial barrier and expression of (97) . only the first study that used a more severe mouse model with higher levels of inflammation and edema found an effect of vitamin d on epithelial barrier function. since inflammation is detrimental for epithelial barrier integrity (98) , it cannot be excluded that the main protective effects of 1,25(oh) 2 d on the epithelial barrier in the first study by shi et al. were in fact exerted through inhibition of inflammation rather than via direct induction of cell junction proteins. 1,25(oh) 2 d might also promote epithelial barrier function through its ability to increase expression of cystic fibrosis transmembrane conductance regulator (cftr) in airway epithelial cells (32) . cftr maintains optimal asl-and mucus hydration, volume and ph that support mucociliary clearance and activity of amps (99) . moreover, cftr is also affected in the airways of smokers and copd patients (100) . in summary, these studies indicate that 1,25(oh) 2 d promotes both the integrity and function of the epithelial barrier and might additionally protect against epithelial damage by dampening inflammatory responses. the loss of epithelial barrier function with a decrease in epithelial polarization and cell-junction proteins and a gain of expression of mesenchymal markers is a hallmark of emt (94) . emt is primarily involved in development, wound healing and stem cell differentiation, and tgf-β signaling plays a major role in this process (101) . elevated tgf-β1 levels are found in the lungs of patients with chronic inflammatory lung diseases and this was associated with cigarette smoking, inflammation and fibrosis (80, 102) . there are indications that 1,25(oh) 2 d counteracts various pathways leading to emt. in mouse models and in airway epithelial cell lines, vitamin d supplementation and 1,25(oh) 2 d, respectively, has been shown to inhibit emt and fibrosis, in particular when this process is induced by tgf-β1 (88, (103) (104) (105) (106) . in addition to maintenance of the epithelial barrier and inhibition of fibrosis as discussed in the previous paragraphs, vitamin d is also actively involved in respiratory host defense by a variety of mechanisms (3, 29) . 1,25(oh) 2 d is an important inducer of amps, which are mostly cationic peptides that have a broad-spectrum antimicrobial activity, the ability to modulate immune responses and to promote epithelial wound repair and angiogenesis (107) . hcap18/ll-37 is likely to be the most prominent amp that is induced by 1,25(oh) 2 d and is expressed in several types of mucosal epithelial cells and immune cells such as monocytes and neutrophils (38, 77, 108) . in macrophages and intestinal epithelial cells, 1,25(oh) 2 d also increases expression of human β-defensin-2 (hbd-2), whereas in keratinocytes expression of both hbd-2 and human β-defensin-3 (hbd-3) is increased by 1,25(oh) 2 d (109) (110) (111) (112) . collectively these data show that amps are modulated by 1,25(oh) 2 d in mucosal tissues, which could have impact on susceptibility to both bacterial and viral infections and on the composition of the microbiota, which will be discussed in the next section. diseases such as copd and asthma are characterized by chronic inflammation, a low-grade and prolonged inflammation that may result in destruction and aberrant repair of surrounding tissue by growth factors, proteases and cytokines that are released at the site of inflammation (113) (114) (115) . cumulative data suggest that vitamin d exerts anti-inflammatory effects via its actions on both innate and adaptive immune responses. upon viral infection or exposure of pro-inflammatory stimuli such as poly(i:c) or pm, 1,25(oh) 2 d attenuates induced expression of cytokines and chemokines e.g., via inhibition of nuclear factor (nf)-κb or oxidative stress, respectively, in (airway) epithelial cells (38, 59, 116) . furthermore, 1,25(oh) 2 d increases expression of the soluble decoy receptor for il-33 (sst2) by airway epithelial cells, which in turn inhibits the actions of the type 2 alarmin il-33 (117) . taken together, these findings suggest that on the one hand 1,25(oh) 2 d protects against infections by enhancing epithelial barrier function and production of amps, and on the other hand 1,25(oh) 2 d induces tolerance and dampens proinflammatory responses in various cell types of the airway mucosa. thereby, 1,25(oh) 2 d may prevent exaggerated inflammatory responses and further damage to the mucosal tissue, qualities that are very relevant in the context of chronic inflammatory (lung) diseases (figure 2) . copd is considered to be a disease of accelerated aging lungs, underscored by markers of aging being increased in these patients partly as a result of oxidative stress (120) . evidence that 1,25(oh) 2 d may protect epithelial cells from oxidative stress was provided by pfeffer et al. who demonstrated that 1,25(oh) 2 d increased expression of the antioxidant gene g6pd in airway epithelial cells. furthermore, 1,25(oh) 2 d increased the ratio of reduced to oxidized glutathione and decreased the formation of 8-isoprostane after exposure to pm (59) . the induction of klotho by 1,25(oh) 2 d might be another 1,25(oh) 2 d-mediated anti-aging mechanism (121) . klotho is an anti-aging protein that is mainly expressed in the kidney, brain and in the lung by airway epithelial cells and exerts its protective effects through the inhibition of inflammation, insulin/igf-1 signaling and activation of forkhead transcription factor (foxo) signaling, which enables removal of reactive oxygen species (ros) (122) (123) (124) . expression of klotho is impaired in the airways of smokers and further decreased in the airways of copd patients and in cultures of the bronchial epithelial cell line 16hbe after cse exposure (124) . these studies suggest that 1,25(oh) 2 d may protect against aging via inhibition of oxidative stress and possibly via its ability to restore klotho expression (figure 2) . however, direct evidence showing that 1,25(oh) 2 d indeed increases expression of klotho in airway epithelial cells is currently lacking. in addition to providing protection against oxidative stress and aging, data from studies using intestinal epithelial cells suggest that 1,25(oh) 2 d may also promote cellular survival via the induction of autophagy and reduction of apoptosis (125, 126) . in chronic inflammatory lung diseases, aberrant activation of autophagy plays a role in disease pathogenesis (127) . a recent study showed that club cells and autophagy-related proteins were both decreased in copd patients and that these proteins were important for club cell structure and function in airways (128) . however, the effects of 1,25(oh) 2 d on autophagy in the airway mucosa of chronic inflammatory lung diseases are still unclear and need to be further evaluated (127) . clearly vitamin d has pivotal actions in host defense that are relevant in the context of chronic inflammatory lung diseases, in which vitamin d deficiency may be prevalent. strategies to promote local levels of 1,25(oh) 2 d or use it as a treatment itself could be therefore of interest. here, we will discuss the latest clinical evidence accompanied with functional in vitro and animal studies that may explain the effects of vitamin d supplementation on typical hallmarks of chronic airway diseases. currently, inhaled corticosteroid (ics)-use with or without long acting bronchodilators is the most frequently used treatment for copd and asthma patients 1 . however, the response to corticosteroids is not always effective in many copd patients and in patients with steroid resistant (sr)-asthma (129) . there are several complex mechanisms that underlie the resistance to corticosteroids in both copd and sr-asthma that include but are not limited to genetic background, impaired glucocorticoid receptor binding, t helper type 17 cell (th17)-inflammation and oxidative stress (e.g., from air pollution or smoking) and decreased numbers of il-10 secreting regulator t cells (tregs), which normally prevent skewing toward th17-inflammation (129) . direct evidence of the ability of 1,25(oh) 2 d to reverse sr was provided by a study showing that ex-vivo stimulation 1 https://goldcopd.org (2019). with 1,25(oh) 2 d promoted generation of il-10-secreting tregs which restored sensitivity toward corticosteroids in cd4+ t cells that were derived from sr-asthma patients (130) . a further potential treatment role of 1,25(oh) 2 d was elegantly illustrated by studies that showed that vitamin d deficiency is associated with decreased steroid responsiveness in asthmatics and by the fact that several potential underlying mechanisms of sr such as oxidative stress and th17-mediated inflammatory responses could be reversed by vitamin d treatment (59, (131) (132) (133) (134) (135) (136) . interestingly, the corticosteroid dexamethasone was shown to increase expression of the 25(oh)d and 1,25(oh) 2 d degrading enzyme cyp24a1 in renal cells and osteoblasts (137) , which suggests a bidirectional interaction between corticosteroids and 1,25(oh) 2 d and could further limit 1,25(oh) 2 d levels for patients. additional research is needed to determine if vitamin d may also improve corticosteroid responsiveness in copd. exacerbations are a major burden for copd patients, they accelerate decline in lung function and frequently result into hospital admissions (138, 139) . exacerbations are often triggered by pollutants or by bacterial-and/or viral infections (82, 140, 141) . copd patients generally have lower serum 25(oh)d levels than age-and smoking-matched controls, which is associated with more and more severe exacerbations (8, 10) . several in vivo and in vitro studies have provided evidence that explain the protective effects of vitamin d on exacerbations in copd patients and this will be discussed accordingly. first of all, pfeffer et al. showed that 25(oh)d and 1,25(oh) 2 d reduce the production of proinflammatory cytokines in part via the ability to enhance antioxidant responses in airway epithelial cells that were exposed to pm (59) . this was also demonstrated in human dcs that were matured in presence of pm, where treatment with 1,25(oh) 2 d counteracted the expansion of proinflammatory il-17a + and ifn-γ + th17.1 cells (134) . in line with this, bolcas et al., showed that vitamin d supplementation counteracted the development of airway hyperresponsiveness and accumulation of th2/th17 cells in mice that had been repeatedly exposed to both diesel exhaust and house dust mite allergens (142) . vitamin d could therefore exert a protective role in air pollution-triggered exacerbations. in addition to its protective effects against pollutants, there is also increasing evidence that 1,25(oh) 2 d may enhance clearance of respiratory viral infections that account for 30-50% as underlying cause of exacerbations in copd patients (143) . infections with respiratory viruses such as hrv, coronaviruses and to a lesser extend respiratory syncytial virus (rsv) and (para)influenza virus are present during exacerbations and may predispose the host toward secondary bacterial infections that can eventually lead to uncontrolled bacterial outgrowth, more severe exacerbations and neutrophilic inflammation (143, 144) . two recent in vitro studies showed that acute exposure to relatively high doses (100-1000 nm) of 1,25(oh) 2 d reduced hrv-infection in undifferentiated cultures of airway epithelial cells (58, 145) . in those models, 1,25(oh) 2 d most likely interfered with viral replication by increasing expression of interferon-stimulated genes and expression of hcap18/ll-37, which has been shown to have direct antiviral activity (58, 145, 146) . in fully differentiated airway epithelial cells, treatment with lower concentrations of 1,25(oh) 2 d (10 nm) during epithelial differentiation had no effect on acute hrv infection (147) . as for other viruses than hrv, both hansdottir et al. and telcian et al. showed that 1,25(oh) 2 d did not decrease rsv infection in airway epithelial cells, but did reduce virus-induced inflammatory responses (58, 116) . in addition, two other studies reported in influenza (h9n2 and h1n1)-infected a549 cells comparable findings (148, 149) . moreover, inhibitory effects of 1,25(oh) 2 d on poly(i:c)-induced inflammatory responses were furthermore confirmed in primary airway epithelial cells hansdottir et al. and by our group (38, 85) . up to now, the afore mentioned studies suggest that higher doses of 1,25(oh) 2 d might be protective against hrv-infections in undifferentiated airway epithelial cells only, whereas for other respiratory viral infections 1,25(oh) 2 d mainly reduces inflammatory responses without affecting viral clearance. however, more studies are needed, especially in differentiated airway epithelial cells using multiple hrv-serotypes that use different receptors for infection to verify if 1,25(oh) 2 d indeed is capable of promoting hrvclearance. there is more consensus about 1,25(oh) 2 d reducing virus-induced inflammatory responses and this may certainly help to alleviate the burden of exacerbations in copd (38, 85) . in addition to viral infections, also bacterial infections are associated with copd exacerbations and account for ∼50% of all exacerbations (150) . due to improved study design and sampling techniques from the lower airways using bronchoscopy in recent decades, the causative role of bacteria in copd-related exacerbations has become clear (150) . this was additionally supported by sethi et al., who found that acquisition of a new strain of pathogenic bacterial species into the airways was linked to copd exacerbations (151) . recent developments in assessing the airway microbiota using 16s rrna sequencing techniques further demonstrated that during exacerbations, the relative abundance of haemophilus, pseudomonas, and moraxella was increased and the microbial composition was shifted toward the proteobacteria phylum (141) . the ability of 1,25(oh) 2 d to promote antibacterial activity was recently demonstrated in cultures of airway epithelial cells. in differentiated airway epithelial cells, we have shown that both 25(oh)d and 1,25(oh) 2 d treatment enhances epithelial expression of hcap18/ll-37 and antibacterial activity against nthi, a gram-negative bacterium, which is associated with copd exacerbations (61, 152) . in addition, yim et al. demonstrated that 1,25(oh) 2 d treatment increased expression of the amp hcap18/ll-37 and killing of pseudomonas aeruginosa and bordetella bronchiseptica, which are both gram-negative bacteria (153) . these observed antibacterial effects of 1,25(oh) 2 d on airway epithelium in vitro were recently confirmed in vivo by vargas buonfiglio et al. the authors demonstrated that vitamin d supplementation increased antimicrobial activity against the gram-positive staphylococcus aureus in asl in healthy non-smokers and was dependent on presence of hcap18/ll-37 (64) . in murine airways, studies showed no effects of 1,25(oh) 2 d on the expression of defb4 or mcramp (the murine homolog for camp) (154) . this can be explained by the fact that both the promotors of mcramp and defb4 lack vdres, suggesting that mice might not be suitable for studying the role of 1,25(oh) 2 d in amp-mediated host defense in infection (155) . indeed, niederstrasser et al. showed no effects of vitamin d deficiency on the susceptibility of mice to pulmonary infection with streptococcus pneumoniae or pseudomonas aeruginosa (156) . however, in a recently developed mouse model by lowry et al., who transfected mcramp knockout mice with the human camp gene, topical vitamin d 3 treatment increased expression of camp and promoted antibacterial effects on the mucosa of the skin (157) . there are also multiple other murine studies that demonstrate protective effects of vitamin d on bacterial infections in the gut, indicating that 1,25(oh) 2 dmediated antibacterial effects are additional modulated by other mechanisms such as via enhancement of epithelial barrier integrity (67, 158) . in conclusion, these observations show that 1,25(oh) 2 d promotes protection against pollutants and enhances clearance of viral-and bacterial infections (both gram-positive and negative bacteria) in combination with a dampening effect on exaggerated immune responses and these features might explain why vitamin d (deficiency) is linked to copd exacerbations. there are strong indications that modulation of immune responses and antibacterial activities by 1,25(oh) 2 d and/or 1,25(oh) 2 d-regulated amps as well as autophagy have implications for the composition of the microbiota at the epithelial mucosa of the airways and the gut (159) . evidence for a role of amps in regulating the composition of the microbiota in the gut came from a variety of studies, including those showing that paneth cell-derived defensins may modulate the composition of the microbiome (160). this notion is further supported by observations showing that many commensal gut bacteria are protected from killing by amps such as the 1,25(oh) 2 d-inducible hcap18/ll-37 and hbd-2, whereas pathogens are in general more sensitive (161) . alterations in the gut microbiota have been linked to many diseases of the gut such as ibd but also with diseases affecting the lungs such as copd and asthma, implicating an important role for the so-called gut-lung axis (162, 163) . the mechanisms that explain how gut microbiota affect lung health and disease are complex and include the production of short chain fatty acids (scfas). scfa have a wide range of effects on both immune and structural cells, and the effect of scfa produced in the intestine on lung immunity may in part be explained by modulation of myeloid cells in the bone marrow, which subsequently migrate to the airways and modulate local immune responses (163) . microbiota that are diverse, rich and contain a higher abundance of scfaproducing species within these populations are considered to be associated with health (164) . in the gut there is strong evidence that both vitamin d deficiency and/or supplementation affect composition of the adult and infant microbiota (164, 165) , specifically in relation to disease (166) . however, due to the limited number of rcts and small sample sizes, the precise effects on the microbiota and the mechanisms involved in this are still unclear (164) . alterations in the lung microbiota are also observed in copd and asthma patients and are likely the result of environmental exposures, airway remodeling, infections and treatments such as the use of antibiotics. this may contribute to disease pathogenesis through altered epithelial innate and adaptive immune responses that damages the airway epithelial barrier and provokes further changes in the lung microbiome that accumulates with increasing disease severity (167, 168) . to date only 2 studies describe a possible influence of vitamin d on composition of the microbiota in the airways (169, 170) . toivonen et al. showed an association between low serum 25(oh)d levels and reduced richness of the nasopharyngeal microbiota and bronchiolitis severity in patients with low 25(oh)d levels (169) , whereas in another study vitamin d supplementation decreased the abundance of staphylococcus aureus, staphylococcus epidermidis and corynebacterium species in sputum samples in vitamin d-deficient cf patients compared to sufficient cf patients (170) . in summary, there is evidence that alterations in the airway or gut microbiota can affect chronic airway disease and that these changes could be related to both vitamin d deficiency and/or supplementation. however, due to the limited number of rcts and small sample sizes more rcts are needed in larger patient populations. the above described protective and therapeutic possibilities of vitamin d, together with observations that many copd patients are vitamin d deficient, suggest that copd patients might benefit from vitamin d supplementation. as discussed elsewhere in this review, the link between circulating 25(oh)d levels and the number of exacerbations has been extensively studied (8) . so far however, only 4 rcts have investigated the effect of vitamin d supplementation in the context of copd: only 2 out of 4 rcts showed that vitamin d supplementation reduces the number of exacerbations (171) (172) (173) (174) . however, in a post-hoc analysis, selecting those patients that were vitamin d deficient, exacerbations were indeed reduced after vitamin d supplementation. jolliffe et al. summarized these 4 rcts and performed a recent individual participant data meta-analysis and concluded that vitamin d supplementation is only protective against exacerbations in copd patients with baseline serum 25(oh)d levels < 25 nmol/l (175) . these important findings suggest that exacerbations in this specific subset of copd patients are connected to vitamin d deficiency and this part can be resolved with supplementation. in summary, the protective effects of vitamin d in patients suffering from copd are most prominent in those with vitamin d deficiency and this would indicate that serum levels 25(oh)d in these patients should always be determined before considering using vitamin d supplementation. since only 4 rcts with relatively small patient populations have been conducted in both vitamin d-sufficient and -deficient copd patients, more rcts are needed, especially in vitamin d-deficient patients. currently, a multicenter rct is being conducted by rafiq et al. in a group of vitamin-deficient copd patients (25(oh)d < 50 nmol/l), which may reveal whether vitamin d supplementation is indeed protective against exacerbations in this group (176) . in addition to the effects of vitamin d supplementation in copd patients, the effects of vitamin d supplementation has also been extensively investigated in other lung diseases (which have associations with vitamin d deficiency) such as asthma, cystic fibrosis, upper respiratory tract infections. most rcts that investigated the effects of vitamin d supplementation were performed in acute respiratory tract infections (artis) and asthma. a recent meta-analysis that assessed the effects of vitamin d supplementation in 25 rcts (11,321 participants) showed that indeed vitamin d supplementation was protective against atris and this effect was again more profound in patients with vitamin d deficiency 25(oh)d < 25 nmol/l at baseline (177) . a recent meta-analysis in asthma that included a total of 14 randomized controlled trials (1,421 participants), indicated that vitamin d supplementation reduced the rate of asthma exacerbations and increased lung function, especially in patients with vitamin d insufficiency (25(oh)d < 75 nmol/l) (178) . interestingly, in asthma patients that were supplemented with vitamin d, the frequency of respiratory infections was reduced, and this effect was related to the increase of hcap18/ll-37 (179) . cf patients with vitamin d deficiency had a higher rate of exacerbations as compared to patients with sufficient 25(oh)d levels (180) . however, only one recent multicenter rct was conducted and indicated that vitamin d supplementation did not affect the number of exacerbations in cf patients with serum 25(oh)d concentrations between 25 and 137.5 nmol/l (181) . in summary, the protective effects of vitamin d supplementation in patients suffering from copd, asthma or artis are most prominent in those with vitamin d deficiency and this would indicate the importance of establishing serum levels 25(oh)d in these patients as supplementation could reduce unnecessary aggravated disease pathology as a result of this deficiency. many drivers of copd pathogenesis such as chronic exposure to noxious particles and gases, which are present in cs and air pollution, proteolytic enzymes, cytokines and chemokines that are released by infiltrating inflammatory cells, are known to harm the epithelial barrier and cause aberrant remodeling of the airway epithelium with important functional consequences for e.g., host defense. a dysfunctional epithelial barrier increases the susceptibility toward bacterial and viral infections, which are important triggers of copd exacerbations and these exacerbations contribute importantly to disease progression. sufficient local levels of 1,25(oh) 2 d may provide partial protection against these effects by reducing the effects of oxidative stress induced by exposure to inhaled oxidants or those derived from recruited inflammatory cells. 1,25(oh) 2 d furthermore protects against impairment of epithelial barrier function by promoting the integrity of the epithelial barrier, and by modulating both innate and adaptive immune responses. protection against the detrimental effects of both bacterial and viral infections is provided by the ability of 1,25(oh) 2 d to promote of antiviral responses, induce expression of amps and modulate of inflammatory responses. taken together, these activities suggest that 1,25(oh) 2 d may provide protection against development and progression of copd, and against disease exacerbations. in addition, the local inflammatory milieu as well as the chronic exposure to noxious particles and gases, which are present in cs and air pollution, may negatively affect synthesis and signaling of 1,25(oh) 2 d. here we discussed recent in vitro studies that demonstrated that disease-associated factors such as inflammation and exposure to cs and air pollution could interfere with 1,25(oh) 2 d signaling and its degradation and activation by affecting expression of vdr, cyp24a1 and cyp27b1, respectively. these findings indicate that 1,25(oh) 2 d levels and its activities on airway mucosa might be impaired especially in patients with copd with exposures to cigarette smoke and cytokines such as tnf-α, il-1β, il-17a and tgf-β1. this suggests that even in patients with sufficient 25(oh)d serum levels the local activity of 1,25(oh) 2 d in the lungs can be improved. we have to start generating more information on both systemic and local 1,25(oh) 2 d levels and gene expression signatures related to 25(oh)d and 1,25(oh) 2 d metabolism or responses in copd (and other chronic inflammatory diseases that are related to vitamin d deficiency), both at baseline and after vitamin d supplementation. this information could lead to improved treatment strategies that enhance local efficacy of 1,25(oh) 2 d, using e.g., specific cyp24a1-inhibitors such as vid400 (182) . alternatively, degradation by cyp24a1 could be prevented by using 1,25(oh) 2 d analogs that are insensitive to cyp24a1-mediated degradation, such as sulfone and sulfoximine derivatives, that also act as a vdr agonist (183) . a third option is to entail the use of combination treatment with vitamin d and anti-inflammatory or certain anti-fibrotic drugs that target cytokines/proteins that are known to potentially decrease local levels and signaling of 1,25(oh) 2 d by inducing expression of cyp24a1 (48, 184, 185) . when considering such strategies, it should be noted that these may enhance the calcemic side effects and lead to unwanted inhibition of the immune system. we therefore need to carefully analyze the preclinical in vivo and in vitro studies and balance the pros and cons of the different strategies. in conclusion, future studies in copd and but also in other chronic inflammatory diseases that are related to vitamin d deficiency, should be designed with more focus on assessing and improving local levels of 1,25(oh) 2 d. these new insights may lead to the development of new treatment strategies, such as those targeting cyp24a1 to enhance local 1,25(oh) 2 d resulting in improved 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modulation of tgf-beta signaling for respiratory disease the authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.copyright © 2020 schrumpf, van der does and hiemstra. this is an open-access article distributed under the terms of the creative commons attribution license (cc by). the use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. no use, distribution or reproduction is permitted which does not comply with these terms. key: cord-335024-0klf75qr authors: saponaro, federica; saba, alessandro; zucchi, riccardo title: an update on vitamin d metabolism date: 2020-09-08 journal: int j mol sci doi: 10.3390/ijms21186573 sha: doc_id: 335024 cord_uid: 0klf75qr vitamin d is a steroid hormone classically involved in the calcium metabolism and bone homeostasis. recently, new and interesting aspects of vitamin d metabolism has been elucidated, namely the special role of the skin, the metabolic control of liver hydroxylase cyp2r1, the specificity of 1α-hydroxylase in different tissues and cell types and the genomic, non-genomic and epigenomic effects of vitamin d receptor, which will be addressed in the present review. moreover, in the last decades, several extraskeletal effects which can be attributed to vitamin d have been shown. these beneficial effects will be here summarized, focusing on the immune system and cardiovascular system. vitamin d is a steroid hormone which exerts a crucial role in the maintenance of bone and calcium homeostasis. the discovery dates back to one hundred years ago, but vitamin d has become a hot topic in endocrinology research only in the last decades, and it has recently emerged as a burning issue due to the covid-19 pandemic, because of the alleged correlation between hypovitaminosis d and high risk of chronic pulmonary diseases and mortality [1] . it is now clear that vitamin d displays a complex multistep metabolism and acts as a hormone on many extra-skeletal targets [2] . the aim of this review is to focus on some new, intriguing, and still incompletely clarified aspects of vitamin d metabolism, such as novel concepts in enzyme regulation, new pleiotropic effects of vitamin d receptor (vdr) activation, and epigenetic effects. vitamin d exists in two forms: vitamin d3, which is the most important source in animals and is produced in the skin; and vitamin d2 which differs from d3 for a methyl group in c24 and a double bond in c22-c23 and is produced by plants [3] . in the skin, vitamin d3 is produced from 7-dehydrocholesterol (7dhc), an intermediate in cholesterol synthesis. exposure to ultraviolet b (uvb) light, in the range of 290-315 nm, determines an electrocyclic rearrangement of the ring in the c9-c10 position, yielding pre-vitamin d (pred3). once pred3 is formed, thermal isomerization to vitamin d3 (vitd3) occurs, with the shift of a hydrogen from c19 to c9 [4] (figure 1 ). this reaction is reversible and pred3 and vitd3 both coexist. from an evolutionary point of view, the observation that vitd3 production is strictly dependent on uvb sheds light on the ancient origin of the hormone, at least 1.2 billion of years ago, when algae began to produce cholesterol [5] . this process has probably developed as a scavenger mechanism to protect from uvb radiation, which is absorbed and dissipated in the rearrangement of double bonds [6] . as a matter of fact, the synthesis of vitd3 depends on the concentration of 7dhc, which in turn depends on 7 dehydrocholesterol reductase (dhcr7) activity. this enzyme catalyzes the reversible reduction of 7dhc into cholesterol. this is part of the biochemical pathway first described this reaction is reversible and pred3 and vitd3 both coexist. from an evolutionary point of view, the observation that vitd3 production is strictly dependent on uvb sheds light on the ancient origin of the hormone, at least 1.2 billion of years ago, when algae began to produce cholesterol [5] . this process has probably developed as a scavenger mechanism to protect from uvb radiation, which is absorbed and dissipated in the rearrangement of double bonds [6] . as a matter of fact, the synthesis of vitd3 depends on the concentration of 7dhc, which in turn depends on 7 dehydrocholesterol reductase (dhcr7) activity. this enzyme catalyzes the reversible reduction of 7dhc into cholesterol. this is part of the biochemical pathway first described by kandutsch and russel in 1960 (alternative to the bloch pathway), in which six isoprene units from acetyl-coa are converted in a cyclized isoprenoid hydrocarbon (lanosterol) and subsequently through oxidative/reductive steps into zymosterol, zymostenol, 7dhc, and finally cholesterol ( figure 1 ) [7] . it was only in 2015 that the kandutsch/russel pathway was completely elucidated and found to have a high activity in the skin, providing the substrate for vitd3 production [8, 9] . in the last fifty years, the discovery of a rare syndrome called smith-lemli-opitz syndrome (slos, omim #270400) which is caused by mutations in the dhcr7 gene provided interesting information [10, 11] . slos has an incidence of 1:40,000 and it is clinically characterized by morphogenic and congenital aberrations, with cognitive retardation and altered behavior [12] . currently 110 different mutations of the dhcr7 gene have been described, that cause enzyme inactivation and accumulation of 7dhc [12, 13] . the most frequent mutations are: a null mutation ivs8-1g>c and a nonsense mutation w151x; the others being missense mutations [9] . slos is more common in countries with low sun exposure and this observation has been interpreted as an heterozygous advantage for mutation carriers to avoid vitamin d (we will refer to vitd3 if not differently specified) deficiency [14] . vitamin in the last fifty years, the discovery of a rare syndrome called smith-lemli-opitz syndrome (slos, omim #270400) which is caused by mutations in the dhcr7 gene provided interesting information [10, 11] . slos has an incidence of 1:40,000 and it is clinically characterized by morphogenic and congenital aberrations, with cognitive retardation and altered behavior [12] . currently 110 different mutations of the dhcr7 gene have been described, that cause enzyme inactivation and accumulation of 7dhc [12, 13] . the most frequent mutations are: a null mutation ivs8-1g>c and a nonsense mutation w151x; the others being missense mutations [9] . slos is more common in countries with low sun exposure and this observation has been interpreted as an heterozygous advantage for mutation carriers to avoid vitamin d (we will refer to vitd3 if not differently specified) deficiency [14] . vitamin d levels have been measured in few slos patients. in 2005 rossi et al. did not find any difference in vitamin d levels in 15 patients with slos, compared to healthy matched controls [15] , but this finding might be attributed to the photosensitivity of slos patients, leading to reduced exposure to the sunlight. on the other hand, movassaghi et al. evaluated 53 pediatric patients with slos and found significantly higher levels of 25 hydroxyvitamin d (25ohd), the marker of vitamin d status, across all seasons (48.06 ± 19.53 ng/ml vs. 30.51 ± 16.14 ng/ml, p < 0.01), without signs of vitamin d intoxication (normal serum calcium) [16] . moreover, the genetic locus dhcr7/nadsyn1 was found to be a determinant of vitamin d status in two contemporary mendelian studies or large-scale genome-wide association studies (gwas) [17, 18] , but the hypothesis that some dhcr7 polymorphisms are correlated with vitamin d status is still controversial and has not been confirmed by some studies [9] . biochemical regulation of dhcr7 seems to be a crucial aspect in vitamin d production, since reduced activity of this enzyme can redirect the pathway from cholesterol to vitamin d biosynthesis. indeed, at the transcriptional level both vitamin d or cholesterol can reduce dhcr7 expression [19] . at the post-translational level, enzyme phosphorylation seems to be important: prabhu et al. showed that inhibition of amp-activated protein kinase and protein kinase a significantly reduced dhcr7 activity, enhancing vitamin d synthesis and reducing cholesterol production [20] . in summary, dhcr7 enzyme is the first line of regulation of vitamin d biosynthesis in the skin, even if the actual production is also modulated by other factors including genetic polymorphisms, age, geographical location and latitude, exposure behavior and cultural conducts, uvb dose, clothing and body surface area (bsa) exposed [1] . concerning regarding sunscreen photoprotection and vitamin d status have recently demonstrated to be inconsistent by an international panel of experts who reviewed the literature and concluded that vitamin d production is not affected by sunscreen use [21] . the skin has long been known as the major source of vitamin d. moreover, keratinocytes of epidermis and hair follicles express the hydroxylases needed to produce the active hormone 1,25 dihydroxy vitamin d [1,25(oh) 2 d] (see section 3), and vdr has been shown to be present on keratinocytes [22] . as a matter of facts, vitamin d produces autocrine and paracrine effects in the skin [23] . in keratinocytes vitamin d has been shown to control differentiation, proliferation, barrier activity and immune response [24] . in selective epidermis vdr knockout animals, predisposition to cancer and impaired wound healing has been observed [25] . moreover, vitamin d deficiency has been related to skin inflammatory diseases and vitamin d analogues have been found to be effective in psoriasis, a proliferative inflammatory skin disease [26] . it is well established that vitamin d requires two subsequent hydroxylation steps to become the active hormone 1,25(oh) 2 d (1,25-dihydroxy vitamin d, calcitriol). the first hydroxylation, in the c25 position, occurs mainly, but not exclusively, in the liver, with a non-regulated and substrate dependent mechanism, as originally reported. as a matter of fact, several enzymes display 25-hydroxylase activity and among them cyp2r1 has been found to play the major role in the liver and testis. cyp2r1 is located in the microsomal p450 fraction of hepatocytes, as reported quite recently by cheng et al. [27] . there are few studies on catalytic properties of the enzyme: in a yeast system, shinkyo et al. demonstrated that cyp2r1 can hydroxylate either vitd3 or vitd2, with higher affinity for the first compared to the latter [28] . subsequently, this observation has been confirmed in escherichia coli and the crystallographic structure of the enzyme has been determined. notably, the pocket for vitamin d entrance faces the hydrophobic membrane domain [29, 30] . the human cyp2r1 gene is located on chr. 11p15.2 (15.5 kb) and contains 5 highly conserved exons, codifying for a 501-amino acid protein. in cyp2r1 knockout mice, 25ohd levels have been found to be decreased by about 50%, the other 50% being ensured by other 25-hydroxylase enzymes [31] . in humans, five cyp2r1 mutations have been identified in patients with different phenotypes, including rickets and low 25ohd levels [32] [33] [34] [35] . moreover, more than 25 single-nucleotide polymorphisms (snps) of cyp2r1 are known and could explain the population variability in 25ohd concentration observed in some genome-wide association studies [17, 18] . particularly, a recent meta-analysis suggested that the rs10741657 polymorphism has a role in the genetically determined vitamin d deficiency [36] . despite the previous hypothesis that cyp2r1 is a non-regulated substrate dependent enzyme, recent evidences challenged this dogma, suggesting that the enzyme expression is modulated by age and metabolic environment. 25ohd levels decrease and are less responsive to supplementation in older patients. roizen et al. attributed this finding to a reduction in cyp2r1 activity in aging, since cyp2r1 mrna and protein content in hepatic tissue of male mice progressively decreased from 26 to 39 and 49 weeks (one-way anova, p = 0.0077). moreover, the 25ohd3/vitd3 ratio was positively correlated with cyp2r1 mrna and consistently declined with age [37] . the metabolic layout also affects cyp2r1 expression. it is known that 25ohd levels are significantly reduced in patients with obesity and type 2 diabetes. the current hypothesis is that vitamin d could be sequestered in adipose tissue or diluted in the high surface of obese people. however, a reduction in cyp2r1 activity has been proposed as an alternative explanation. cyp2r1 activity was diminished in an animal model of high fat diet (hfd) obesity, since cyp2r1 mrna was significantly lower (40%) compared to lean mice, whereas other 25-hydroxylase enzymes were not altered by hfd. cyp2r1 protein expression and enzyme activity was reduced by 50% in obese mice liver homogenates compared to controls [38] . other investigators observed that 12 h-fasting strongly reduced cyp2r1 mrna and the effect was even higher after 24 h (50% and 80% respectively), both in mice or rat models [39] . protein expression and enzymatic activity were reduced accordingly. in different models of diabetes (hfd induced type 2 diabetes and streptozocin induced type 1 diabetes) a similar suppression of liver cyp2r1 activity was observed [39] . at least two potential signaling pathways have been involved in cyp2r1 modulation: the peroxisome proliferator-activated receptor γ coactivator 1-α/estrogen related receptor α (pgc1α/errα) and the glucocorticoid receptor (gr) axis. the pgc1α/errα pathway is physiologically activated during fasting and it is pathologically induced in diabetes [40, 41] : overexpression of this signaling strongly decreased cyp2r1 hydroxylate activity [39] . however, other mechanisms are likely to exist, since suppression of cyp2r1 by starving was observed also in pgc1α knockout mice. aatsinki et al. showed that pharmacological inhibition of gr prevented cyp2r1 induction by fasting, suggesting a role for this pathway in hydroxylase regulation [39] . these findings suggest a complex crosstalk between vitamin d and several metabolic pathways, so that 25ohd levels undergo a refined control, and do not simply mirror vitamin d intake, as usually assumed. in addition, further hydroxylase activities have been found in the liver. they include cyp27a1, which is located in the mitochondria and has a major role in cholic acids formation [42] , and cyp3a4, which has a compensatory c25 hydroxylase activity [43] . besides the well-known role of vitamin d in calcium and bone metabolism, in the last ten years additional effects have been described, with special regard to the immune system. from an evolutionary point of view, specific investigations and genome-wide association studies demonstrated that the ancient and initial role of vitamin d was likely the regulation of genes involved in energy metabolism [5] . during vertebrate evolution, skeletal and immune systems evolved quite simultaneously and vitamin d was a central driver of the osteo-immune bidirectional interactions [44] . as a matter of fact, the primary reason for these extra-skeletal effects of vitamin d is the ability of different tissues to produce the active hormone, i.e., 1,25(oh) 2 d, locally, thanks to the enzyme 1α-hydroxylase. despite the existence of several 25-hydroxylase enzymes, cyp27b1 has been demonstrated to be the only 1α-hydroxylase in human, and different tissues isoforms exist [45] . it is noteworthy that whereas 25ohd is easily detectable in blood and urine (in the order of ng/ml), the concentrations of 1,25(oh) 2 d are much lower (order of pg/ml) and are largely regulated peripherally with autocrine and paracrine mechanisms, which escape systemic endocrine control and detection. in 1971, renal cyp27b1 was identified and the kidney was thought to be the only source of 1,25(oh) 2 d [46] . the renal form of cyp27b1 is regulated by at least three hormones, with a crucial role in calcium-bone metabolism ( figure 2 ): parathyroid hormone stimulates the hydroxylation, whereas fgf23 and 1,25(oh) 2 d itself inhibit it, in response to calcium and phosphate concentrations [47, 48] . calcitonin has also been shown to stimulate renal cyp27b1 and leptin to inhibit, probably via fgf23 ( figure 2 ) [49] . beyond classical renal cyp27b1 modulation, the novelty in the field is represented by a completely different regulation of cyp27b1 in the other tissues, particularly in the immune system. in the 1980 s, it was observed that the administration of 1,25(oh) 2 d to blood myeloid cells induced their maturation into white cells [50] . the contemporary report of hypercalcemia and high levels of 1,25(oh) 2 d in an anephric patient with sarcoidosis, suggested that c1 hydroxylation could occur outside the kidney [51] . in 1983, adams et al. observed 1,25(oh) 2 d production from macrophages in sarcoidosis patients [52] . it is now known that macrophages are involved in the pathophysiology of many inflammatory and/or autoimmune diseases (sarcoidosis, tuberculosis, chron's disease, foreign body granulomata, cryptococcosis and others), and that they are able to produce 1,25(oh) 2 d at high levels by their own cyp27b1 [53] . differently from renal cyp27b1, the macrophage isoform is not controlled by pth. 1,25(oh) 2 d formation depends only on substrate availability and is not limited by product accumulation, which was interpreted as absence of catabolic enzymes control [52, 53] . this is likely the reason why in sarcoidosis 1,25(oh) 2 d production is persistent and eventually leads to systemic hypercalcemia [54] . the regulation of cyp27b1 in macrophages and monocyte has been elucidated and it is under the control of cytokines and inflammation. macrophages' cyp27b1 is stimulated by interferon-γ (infγ), tumor necrosis factor α (tnfα), interleukin (il) 1, 2 and 15, but not by pth. moreover, dexamethasone inhibits cyp27b1 [55] . in addition to macrophages, also dendritic cells (dc), th lymphocytes and b lymphocytes express cyp27b1, but only when they are activated. in these cells 1,25(oh) 2 d functions as a 1αhydroxylase inhibitor, thus controlling their activation and proliferation. as described further in details in paragraph 6, 1,25(oh) 2 d exerts many autocrine and paracrine functions on immune system cells, ensuring a feedback control on immune cells themselves [55] . beyond classical renal cyp27b1 modulation, the novelty in the field is represented by a completely different regulation of cyp27b1 in the other tissues, particularly in the immune system. in the 1980′s, it was observed that the administration of 1,25(oh)2d to blood myeloid cells induced their maturation into white cells [50] . the contemporary report of hypercalcemia and high levels of 1,25(oh)2d in an anephric patient with sarcoidosis, suggested that c1 hydroxylation could occur outside the kidney [51] . in 1983, adams et al. observed 1,25(oh)2d production from macrophages in sarcoidosis patients [52] . it is now known that macrophages are involved in the pathophysiology of many inflammatory and/or autoimmune diseases (sarcoidosis, tuberculosis, chron's disease, foreign body granulomata, cryptococcosis and others), and that they are able to produce 1,25(oh)2d at high levels by their own cyp27b1 [53] . differently from renal cyp27b1, the macrophage isoform is not controlled by pth. 1,25(oh)2d formation depends only on substrate availability and is not limited by product accumulation, which was interpreted as absence of catabolic enzymes control [52, 53] . this is likely the reason why in sarcoidosis 1,25(oh)2d production is persistent and eventually leads to systemic hypercalcemia [54] . the regulation of cyp27b1 in macrophages and monocyte has been elucidated and it is under the control of cytokines and inflammation. macrophages' cyp27b1 is stimulated by interferon-γ (infγ), tumor necrosis factor α (tnfα), interleukin (il) 1, 2 and 15, but not by pth. moreover, dexamethasone inhibits cyp27b1 [55] . in addition to macrophages, also dendritic cells (dc), th lymphocytes and b lymphocytes express cyp27b1, but only when they are activated. in these cells 1,25(oh)2d functions as a 1αhydroxylase inhibitor, thus controlling their activation and proliferation. as described further in details in paragraph 6, 1,25(oh)2d exerts many local production of 1,25(oh) 2 d by cyp27b1 for autocrine/paracrine purpose has been described in many other tissues, including epithelial tissues, placenta, bone, endocrine glands (parathyroid, pancreatic islets, thyroid, adrenal medulla, gonads), brain, liver and endothelia [53] . in the majority of cases, experimental data suggest that the regulation of local cyp27b1 escapes the classical patters of the renal isoform and is due to local tissue-specific stimuli [53] . in figure 2 the main regulators of extrarenal cyp27b1 isoforms are summarized. more than 50 metabolites of vitamin d have been described in the last decades and some of them display a certain interest because of their biological activity. the best-known catabolic enzyme is cyp24a1, belonging to mitochondrial p450 fraction and encoded by the cyp24a1 gene on chr. 20q13.2 [48] . cyp24a1 can hydroxylase both 25ohd and 1,25(oh) 2 d, producing 24r,25(oh) 2 d and 1,24,25(oh) 3 d, respectively. the same enzyme further catalyzes the hydroxylation of these products in multiple steps, yielding a series of 24-and 23-hydroxylated derivatives. the final products are the inactive calcitroic acid or 26,23-lactone excreted with bile or urine (figure 1 ). cyp24a1 is up-regulated by calcitriol and fgf23 and is inhibited by pth and hypocalcemia. cyp24a1 has been detected in many tissues expressing vdr, and it plays a crucial role in the local modulation of vitamin d activity [56] . pathogenic variants of cyp24a1 have been described and they are responsible for idiopathic infantile hypercalcemia (iih, omim 143880), a rare disorder due to impaired vitamin d catabolism and subsequent hypercalcemia. in particular, biallelic variants (in homozygosis or heterozygosis) have a severe phenotype with hypercalcemia that may occasionally lead to death in infant age [57] . in addition to cyp24a1, other minor metabolic pathways have been described and still need further evaluation. recently, the c-3 epimerization pathway has been identified, which leads to the production of several c-3 epimer metabolites, in which the hydroxyl group on c3 has the alpha rather than the beta orientation in the space. epimeric metabolites have been shown to be highly expressed particularly in neonates and young children, but the physiological role of this redundant pathway needs to be elucidated [58] . the presence of so many metabolites is stimulating the development of novel and more accurate analytical techniques. since 1970, when high performance liquid chromatography techniques have been introduced, they have been continuously improved and today the most recent lc-ms-ms assay is referred as the "gold standard" method [59] [60] [61] [62] . this is due to the high sensitivity, reproducibility and accuracy, this latter also being influenced by the capability to discriminate 25ohd2 and 25ohd3, as well their epimeric forms. moreover, it offers the possibility to measure different vitamin d metabolites at the same moment [63] . right now, five intermediates have been measured with standardized techniques, namely: vitamin d, 25ohd, 1α,25(oh)2d, 24r,25(oh)2d and c3-epi25(oh)d and procedures are listed in the joint committee for traceability in laboratory medicine (jctlm) database [64] [65] [66] [67] . in 2009 the use of lc-ms-ms for vitamin d metabolites measurement was advised by the nutritional health and nutrition examination survey [68] in usa and from the uk food standard agency (fsa) in their national diet and nutrition survey [69] . the hope is that with lc-ms-ms further insight in the complexity of vitamin d metabolites will be achieved [70, 71] . transport of vitamin d metabolites is accounted for 85% by vitamin d binding protein (dbp) with high affinity and 15% by albumin with low affinity [72] . dbp, initially known as gc-globulin, is a multitasking protein which is very conserved in vertebrates' evolution. the human gene for dbp is located on chr. 4, close to other genes for albumin family proteins and encodes for a 458 amino acid single chain protein [73] . all metabolites of vitamin d can be bound by the same binding site of dbp, even if 25ohd and 1,25(oh) 2 d have the highest affinity [74] . free 25ohd represents 0.03% and 1,25(oh) 2 d 0.4% of the total amount of the metabolites and have been classically interpreted as the only active hormone to enter cells (free hormone hypothesis [75] ). however, at least in some organs like kidney, the free hormone hypothesis has been recently revised. indeed, it has been shown that the large transmembrane protein megalin is present on the apical side of the proximal tubule cells and acts as a receptor for the complex vitamin d-dbp, together with cubulin and disabled-2 proteins [76] . accordingly to this hypothesis, knockout mice for lrp2 (encoding for megalin) show severe osteomalacia and poor survival, demonstrating the pivotal role of dbp binding capacity in the kidney [77] . on the other hand, the role of this mechanism in the other tissues is still debated: megalin is expressed in several tissues in which vitamin d exerts extraskeletal functions, but megalin-mediated uptake of dbp has not been completely elucidated. summarizing recent evidences, dbp functions as a large pool reservoir of circulating 25ohd, which prevents for vitamin d deficiency when supply is low. moreover, dbp also functions as a regulator for vitamin d access to cells in kidney and most likely in the other peripheral tissues [72] . the human vitamin d receptor gene (vdr) is located on chr. 12 and contains nine exons. in the last twenty years vdr cdnas were obtained and cloned from several species (human, mice, rats, chicken, frog, quail), revealing a great homology among species and many conserved regions [78, 79] . vdr is a polypeptide of 50,000 da formed by a single amino acid chain. it is almost ubiquitous in the body since it is expressed in at least thirty tissues, involved in bone metabolism (intestine, bone, cartilage, kidney) or in other extra-skeletal functions (heart, immune system, adipose tissues and many others) [80, 81] . vdr belongs to the nuclear receptor superfamily along with the receptors of other steroid hormones. these receptors share the ability to bind their ligands at nanomolar concentrations in a specific conserved ligand binding domain (lbd), with a pocket of 400-1400 a3 [82, 83] . when vdr binds to 1,25(oh) 2 d, it can reach the nucleus and forms a heterodimer with retinoid x receptor (rxr), able to interact with gene response elements. this interaction is crucial for assembling the transcriptional machinery at the promoters of 1,25(oh) 2 d targets genes [84] . the crystallographic structure of the receptor bound to its major ligand 1,25(oh) 2 d was resolved by rochel et al. [85] . the ligand binding domain (lbd) is formed by 12 αhelices (h1-12) packed in three layered α helical sandwich and three stranded β sheets. when the ligand binds, h12 is able to shift and deeply closes the ligand into the pocket binding site [85] . the dna binding domain is formed by two zinc fingers, where four cysteines residues maintain zinc in a tetrahedral configuration [78] . more than 3% of the entire genome from zebrafish to human is under direct or indirect vdr control, so that more than 11,000 genes have been identified as putative targets for vdr, controlling many pivotal mechanisms such as metabolism, cells adhesion, tissue differentiation, development and angiogenesis [86] . some of the major signaling pathways activated by vdr are summarized in table 1 . table 1 . major signalling pathways activated by vdr. as a matter of fact, vitamin d has recently become a hot topic in nutrigenomics that is the discipline studying the environmental factors able to affect the transcriptome and the epigenome. the latter is a novel and interesting field in vitamin d research. chromatin is the structure in which genomic dna, nucleosome-forming histone proteins and non-histone proteins are packed in the nucleus, and it represents the scaffold of the entire human heritable information [79] . chromatin exists in at least two different forms: less dense and transcription-available euchromatin and compact, functionally repressed heterochromatin. these different conformations are largely related to post-translational changes of chromatin proteins. epigenomic studies all the modifications (such as histone methylation or acetylation) which occur in chromatin in the absence of genomic changes [87] . these epigenetic alterations can be very stable and heritable or unstable and transient and are catalyzed by the so-called chromatin modifier enzymes. a few hundred genes for chromatin modifier enzymes have been described, which as carlberg brilliantly wrote: "add (write), interpret (read) or remove (erase) post translational histone modifications" [88] . vdr acts as a transcription factor and is able to modulate genes encoding for chromatin modifier enzymes, thus modulating the human epigenome. one example is kdm6b/jmjd3, a histone h3 lysine demethylase, which plays a crucial role in development. it has been shown to be induced by 1,25(oh) 2 d/vdr and in turn to modulate vitamin d metabolism. pereira et al. showed that 1,25(oh) 2 d/vdr induced jmjd3 rna in human colon cancer cells, suggesting a role for 1,25(oh) 2 d in colon cancer epigenomic events [89] . another level of epigenomic control by vdr is the direct interaction between vdr and chromatin proteins. furthermore, vdr has been shown to interact with co-activators, such as those of the ncoa family, or co-repressors, such as ncor1 proteins, which respectively lead to local chromatin opening or closing [90] . the enrolment of co-regulators is also important in the tissue specific and cell-specific regulation of differentiation. an example is the skin were the change of different 1,25(oh)2d/vdr genes controlling the process of differentiation of the keratinocytes is regulated by the subsequent recruitment of different co-regulators of the mediator complex family (med) in the early stage and steroid receptor co-activator (src3) in the later stages [23] . vdr seems to interact with more than 50 nuclear proteins, and deeply affects chromatin remodeling [91] . vdr has also been detected in a different subcellular location, namely as a transmembrane receptor which appears to be activated by vitamin d analogues with a different configuration (6s-cis), if compared to those that activate the nuclear vdr (6s-trans). transmembrane vdr is one of the receptors by which vitamin d exerts non genomic, rapid effects on its target cells and tissues. some non-genomic effects of vitamin d, which occur rapidly over minutes or hours, include rapid intestinal absorption of calcium (transcaltachia), secretion of insulin by pancreatic cells, opening of voltage-gated ca2+ and cl-channels in osteoblasts, and the rapid migration of endothelial cells [92] . the classical role of 1,25(oh) 2 d in calcium/bone metabolism, namely the regulation of intestinal calcium absorption, renal calcium reabsorption and mobilization of calcium and phosphate from bone, has been known for decades and is beyond the aims of the present review. on the other hand, in the last decade a mean of 3000 papers per year have been published on vitamin d, pushed by new findings concerning extra-skeletal effects of this hormone [93] . in this section we will summarize part of these discoveries and the effects of 1,25(oh) 2 d on several districts, particularly the immune system and the cardiovascular system ( figure 3) . actions of vitamin d on skin have been summarized in the first paragraph. methylation or acetylation) which occur in chromatin in the absence of genomic changes [87] . these epigenetic alterations can be very stable and heritable or unstable and transient and are catalyzed by the so-called chromatin modifier enzymes. a few hundred genes for chromatin modifier enzymes have been described, which as carlberg brilliantly wrote: "add (write), interpret (read) or remove (erase) post translational histone modifications" [88] . vdr acts as a transcription factor and is able to modulate genes encoding for chromatin modifier enzymes, thus modulating the human epigenome. one example is kdm6b/jmjd3, a histone h3 lysine demethylase, which plays a crucial role in development. it has been shown to be induced by 1,25(oh)2d/vdr and in turn to modulate vitamin d metabolism. pereira et al. showed that 1,25(oh)2d/vdr induced jmjd3 rna in human colon cancer cells, suggesting a role for 1,25(oh)2d in colon cancer epigenomic events [89] . another level of epigenomic control by vdr is the direct interaction between vdr and chromatin proteins. furthermore, vdr has been shown to interact with co-activators, such as those of the ncoa family, or co-repressors, such as ncor1 proteins, which respectively lead to local chromatin opening or closing [90] . the enrolment of co-regulators is also important in the tissue specific and cell-specific regulation of differentiation. an example is the skin were the change of different 1,25(oh)2d/vdr genes controlling the process of differentiation of the keratinocytes is regulated by the subsequent recruitment of different co-regulators of the mediator complex family (med) in the early stage and steroid receptor co-activator (src3) in the later stages [23] . vdr seems to interact with more than 50 nuclear proteins, and deeply affects chromatin remodeling [91] . vdr has also been detected in a different subcellular location, namely as a transmembrane receptor which appears to be activated by vitamin d analogues with a different configuration (6scis), if compared to those that activate the nuclear vdr (6s-trans). transmembrane vdr is one of the receptors by which vitamin d exerts non genomic, rapid effects on its target cells and tissues. some non-genomic effects of vitamin d, which occur rapidly over minutes or hours, include rapid intestinal absorption of calcium (transcaltachia), secretion of insulin by pancreatic cells, opening of voltagegated ca2+ and cl-channels in osteoblasts, and the rapid migration of endothelial cells [92] . the classical role of 1,25(oh)2d in calcium/bone metabolism, namely the regulation of intestinal calcium absorption, renal calcium reabsorption and mobilization of calcium and phosphate from bone, has been known for decades and is beyond the aims of the present review. on the other hand, in the last decade a mean of 3000 papers per year have been published on vitamin d, pushed by new findings concerning extra-skeletal effects of this hormone [93] . in this section we will summarize part of these discoveries and the effects of 1,25(oh)2d on several districts, particularly the immune system and the cardiovascular system ( figure 3) . actions of vitamin d on skin have been summarized in the first paragraph. immune system: vitamin d seems to influence both the innate and the acquired immune system with complex effects, which are still not completely elucidated. we have already outlined that 1 α-hydroxylation produces the active hormone within different cells of immune system, where it exerts autocrine and paracrine effects. a very recent study on vitamin d target genes evaluated and compared all the available transcriptome-wide datasets from human monocytes treated with 1,25(oh) 2 d in vitro [94] . 15 vdr target genes with a potential pivotal role in the immune response were identified and classified in three groups. group 1 included camp, cd14, fn1, and trem1 genes, which have a low basal expression but are highly inducible after 1,25(oh)2d/vdr activation and encode proteins involved in the immediate response to infection. in general, effectors of the lps/tlr4 signaling pathways seem to be coded by these genes. group 2 includes lilrb4, lrrc25, mapk13, sema6b, thbd, and themis2 genes, which are required in the general response to infection. group 3 includes acvrl1, cd93, cebpb, ninj1, srgn, genes involved in long-term autoimmunity mechanisms, which do not require ligand binding to vdr and are likely involved in epigenomic regulation [94] . mathieu et al. recently reported a comprehensive revision of vitamin d effects on the immune system [95] . both monocytes and macrophages express vdr, the latter at higher levels than the former. 1,25(oh) 2 d has been shown to stimulate differentiation and proliferation of monocytes, whereas on activated macrophages the overall effect leads to reduced inflammatory response. indeed, 1,25(oh) 2 d stimulates the production of il-10 (anti-inflammatory) and decreases the release of pro-inflammatory effectors such as il-1β, il-6, tumor necrosis factor-α (tnfα), receptor activator of nuclear factor kappa-b ligand (rankl), and cyclo-oxygenase-2 (cox-2) [96] . the signaling pathways proposed to mediate the anti-inflammatory effect include: (i) upregulation of mapk and mkp and inhibition of lps/p38, (ii) modulation of thioesterase superfamily member 4, with subsequent cox2 inhibition, (iii) direct antimicrobial effect by cathelicidin antimicrobial peptide (camp) induction, (iv) anti-oxidative effect due to increased glutathione reductase (gr) with drop of reactive oxygen species [95, 96] . on the other hand, vitamin d inhibits the acquired immune system, mainly reducing the expression of mhc class ii and co-signaling molecules on antigen presenting cells, decreasing the activity of th1 and th17 cells, and up-regulating regulatory t cells. the final result is to promote the regulatory and protective phenotype of t cells [97] . from a clinical perspective, vitamin d deficiency is strongly associated with increased risk of infections, dysregulation of the immune system and autoimmune diseases [1] . a specific issue that recently gained a great relevance is the relationship between hypovitaminosis d and pulmonary infections. vitamin d concentration is inversely related to the risk of multiple pulmonary injuries such as pneumonia, community acquired pneumonia, ards, sepsis, heart failure and mortality from pulmonary infections [98] [99] [100] [101] [102] . a recent large metanalysis on more than 10,000 subjects demonstrated that vitamin d supplementation had a protective role in acute respiratory infections, in adults [103] . due to these findings, an important role for vitamin d has very recently been suggested in the treatment or prevention of covid-19. in march 2020, covid-19 spread as a pandemic emergence due to the new β coronavirus severe acute respiratory syndrome coronavirus 2 (sars-cov-2) [104] . in the absence of specific treatments, public health measures are required to characterize risk factors and prevent the infection or the progression of the disease. among the factors that might contribute to the development of severe covid-19, vitamin d status was proposed as a credible candidate [105, 106] , even if the evidence is still preliminary. at present, the following observations suggest a possible role of vitamin d in reducing sars-cov-2 risk: (i) the seasonal flare of covid-19, which coincides with the nadir of vitamin d levels, (ii) the previously mentioned association between hypovitaminosis d and pulmonary infections, (iii) the anti-inflammatory role of vitamin d which could be of benefit against the so called "cytokine storm", which seems to be a pathophysiological pivotal player in sars-cov2 morbidity and mortality [107] . several short reports have been published and are still emerging at the moment of this writing, encouraging to analyze the relationship between vitamin d and covid-19 [105, 106, 108] . in the setting of autoimmune diseases, there is an interesting association between low levels of vitamin d and increased risk of developing multiple sclerosis (ms). some prospective studies have demonstrated that increasing levels of 25ohd significantly reduce the risk of ms, among caucasian people [109] ; moreover, cholecalciferol supplementation associated with interferon β1b significantly reduced the activity of the disease as evaluated by mri, compared to interferon β1b alone [110] . cardiovascular system: in the early 1980s, robert scragg proposed the hypothesis that the increase in cardiovascular diseases usually observed in winter might be a result of low 25ohd levels, due to the reduced sunlight exposure [111] . this idea turned on a great interest in the potential cardiovascular benefits of vitamin d, leading to several publications over the last ten years. however, the physiological role of vitamin d in the cardiovascular system is still unclear. vdr is expressed in rat and human heart tissue and has a potential role as a modulator of cardiac hypertrophy and failure. this hypothesis is based on the concept that altered intracellular handling of ionized calcium is related to the impaired contractility of the myocardium in heart failure (hf), since 1,25(oh) 2 d is directly involved in calcium-dependent cellular processes, including synthesis of calcium-binding protein, activation of adenylate cyclase, rapid activation of voltage-dependent calcium channels, and modulation of sarcoplasmic reticulum calcium uptake and release [112] . another possible mechanism is the putative role of 1,25(oh) 2 d as a negative regulator of the renin-angiotensin system (ras). in both normotensive and hypertensive subjects, 1,25(oh) 2 d serum levels are inversely associated with pra (plasma renin activity), suggesting a potential role of vitamin d in hypertension via renin regulation. recent evidence showed that nuclear hormone receptors, including vdr, liver x receptor (lxr) and peroxisome proliferators-activated receptor (ppar), regulate renin gene transcription via specific elements in the renin promoter [112] . strong support for the involvement of vitamin d in the pathogenesis of cardiovascular diseases comes from vdr knockout mice (vdr −/− ). these mice develop typical signs of hf, including activation of the renin-angiotensin-aldosterone system, cardiac hypertrophy, high blood pressure, and increased levels of atrial natriuretic peptide. furthermore, the development of hypertension in vdr −/− mice can be corrected with the administration of ace inhibitors, only as long as vitamin d levels are sufficient [113] [114] [115] . additional effects of 1,25(oh) 2 d concern the vasculature; indeed, vitamin d can modulate the growth of smooth muscle and endothelial cells and can induce the activation of vasodilatory and antithrombotic genes [116] . moreover, vitamin d seems to suppress inflammation and to reduce update of oxidized ldl, giving potential vascular benefits. vdr −/− mice show hypercoagulability and atherosclerosis [117, 118] . from a clinical point a view, low serum 25ohd levels have been associated with increased risk of cardiovascular diseases, including hypertension, coronary artery disease, ischemic heart disease, hf, stroke, and type 2 diabetes [119] [120] [121] [122] [123] [124] . convincing data has been produced particularly on the association between hypovitaminosis d and hf, which still is a major public health disease with poor prognosis. a large cohort of patients with hf has been evaluated by gotsman et al. who described the variations of serum 25ohd during the year and the effect of vitamin d deficiency and supplementation on mortality. in their population, vitamin d deficiency strongly predicted low survival rate and vitamin d supplementation succeeded in reducing mortality [125] . our group recently reported results from an italian cohort of 261 patients with hf in whom low serum levels of 25ohd were inversely correlated with a validated score of hf mortality, namely the metabolic exercise cardiac kidney index or mecki score [126] . in a subgroup of these patients, cardiovascular outcomes have been also reported: patients with hf had mean serum levels of 25ohd statistically lower than healthy subjects (45.2 ± 23.7 nmol/l vs. 58.2 ± 24.0 nmol/l, p < 0.001) and a higher prevalence of vitamin d insufficiency (serum 25ohd < 50 nmol/l or 20 ng/ml) (61.1% vs. 39.5%, p < 0.001), associated with higher mortality risk [127] . several meta-analyses on retrospective studies [119, [128] [129] [130] [131] [132] [133] confirmed a consistent association between a low vitamin d status and cardiovascular endpoints (myocardial infarction, hypertension, hf) and/or mortality. on the other hand, randomized controlled trials (rcts) and mendelian randomization studies so far have not succeeded in proving a benefit of vitamin d supplementation. however, it is likely that the latter investigations are affected by some methodological limitations (no clear and homogeneous dosage of vitamin d, no measurement of basal 25ohd levels, design of the study targeted on skeletal outcome) therefore it is still unclear if vitamin d has a causative role in cardiovascular diseases or is rather a marker of poor health in chronic disease. adipose tissue and glucose/lipid metabolism: recent studies showed an association between low levels of vitamin d and almost all aspects of the metabolic syndrome, namely type 2 diabetes mellitus (t2dm), impaired fasting glucose, hypertension, dyslipidemia, obesity, and insulin resistance. therefore, several investigations focused on the role of vitamin d in adipose tissue biology. some studies have shown a negative correlation between vitamin d and leptin or resistin, as well as and an inverse correlation with adiponectin. [134, 135] old preclinical studies have demonstrated that a normal activity of pancreatic β cells required adequate levels of vitamin d and functioning vdr [136] , while more recent studies on vitamin d deficient mice showed impaired glucose-stimulated insulin secretion in pancreatic islets [137] . a recent review by mathieu supported role of vitamin d in diabetes. indeed, vdr is present in all tissues involved in t1 and t2dm, either in pancreatic islets and immune cells, adipose tissue, liver and muscle. in all these tissues and organs, the machinery responsible for the local production of 1,25(oh)2d and its metabolites is also present. moreover, low levels of vitamin d are associated with increased risk of t1 and t2dm and in several animal models vitamin d supplementation improved islets function and insulin sensitivity. however, convincing randomized prospective studies in humans are still lacking and necessary. muscle: it has been ascertained that vitamin d deficiency is responsible for low muscle strength, balance disorders and an increased risk of falls. in a model of vdr null mice, a specific phenotype due to immature muscle-specific genes developed and cardiomyocyte-specific vdr knockout induced cardiac hypertrophy and failure [138, 139] . observational studies have confirmed as association between low vitamin d levels and muscle weakness in children and in the elderly, while supplementation improved muscle function as well as energy recovery after exercise [140, 141] . cancer: vdr has been shown to be expressed by cancer cell lines and it is hypothesized to play a role in the pathogenesis and progression of cancer. cyp27b1 is also expressed at high level in many cancer cells and tissues and 1,25(oh) 2 d has been proved to have an anti-proliferative effect firstly on myeloma and melanoma cells and subsequently on other cancerous cell lines [142] . on the other hand, cyp24a1 is overexpressed in cancer and several vitamin d analogues and/or cyp24a1 inhibitors have been tested in preclinical studies [143] . animal models with vdr knockout do not spontaneously develop neoplasia, however, they have been demonstrated to be more susceptible to develop malignancies under stimulus [144] and in several studies on different animal models vitamin d analogues slowed cancer progression and the development of metastases [145] . an interesting example is that of melanomas: 1,25(oh) 2 d and analogues have been clearly showed a beneficial effect as inhibitors of proliferation, plating efficiency and anchorage-independent growth of melanomas cells in vitro experiments and in vivo animal models and have been proposed as potential adjuvant therapies, especially if topically delivered [146, 147] . clinical data regarding vitamin d and cancer are more controversial: low vitamin d levels have been associated with a higher risk of cancer, but rcts have not been revealed any significant benefit from vitamin d supplementation. however, international multicenter rcts are still ongoing, specifically designed for the extra-skeletal effects of vitamin d, and they will hopefully shed light on the controversies [1] . vitamin d has been clearly recognized to be a molecule with several endocrine, paracrine and autocrine effects on multiple tissues and organs, beyond skeletal homeostasis maintenance. research is still very active in this field, with the aim of clarifying many aspects of the complexity of vitamin d and its metabolites. new concepts have emerged in the last years, namely the special role of the skin, the metabolic control of liver hydroxylase cyp2r1, the specificity of 1α-hydroxylase in different tissues and cell types and the genomic, non-genomic and epigenomic effects of vdr. many issues need further investigation and many questions are still waiting for answers, which will hopefully become available in the near future. funding: this research received no external funding. the authors declare no conflict of interest. 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hypertrophy calcium intake and hip fracture risk in men and women: a meta-analysis of prospective cohort studies and randomized controlled trials relevance of vitamin d in muscle health 1,25-dihydroxyvitamin d3 and malignant melanoma: the presence of receptors and inhibition of cell growth in culture vitamin d analogues: potential use in cancer treatment function of the vitamin d endocrine system in mammary gland and breast cancer the role of vitamin d in reducing cancer risk and progression on the role of classical and novel forms of vitamin d in melanoma progression and management vitamin d signaling and melanoma: role of vitamin d and its receptors in melanoma progression and management this article is an open access article distributed under the terms and conditions of the creative commons attribution (cc by) license key: cord-016009-qa7bcsbu authors: starkel, julie l.; stapke, christina; stanley-o’malley, abigail; noland, diana title: respiratory date: 2019-10-07 journal: integrative and functional medical nutrition therapy doi: 10.1007/978-3-030-30730-1_51 sha: doc_id: 16009 cord_uid: qa7bcsbu lung disease rivals the position for the top cause of death worldwide. causes and pathology of the myriad lung diseases are varied, yet nutrition can either affect the outcome or support treatment in the majority of cases. this chapter explores the modifiable risk factors, from lifestyle changes to dietary intake to specific nutrients, anti-nutrients, and toxins helpful for the nutritionist or dietitian working with lung disease patients. general lung health is discussed, and three major disease states are explored in detail, including alpha-1 antitrypsin deficiency, asthma, and idiopathic pulmonary fibrosis. although all lung diseases have diverse causes, many integrative and functional medical nutrition therapies are available and are not being utilized in practice today. this chapter begins the path toward better nutrition education for the integrative and functional medicine professional. anti nutrients and inhibitors of lung physiology -942 51 lung disease is far more prevalent worldwide than commonly thought. in fact, death from chronic lung disease is increasing, and as of 2017, chronic obstructive pulmonary disease (copd) has become the third leading cause of death in the united states in the past decade, disproportionately affecting the elderly [1] . another lung disease, asthma, affects 1 in 13, or about 25 million americans, according to the centers for disease control and prevention and the national center for health statistics [2] . this is 7.6% of adults, more women than men, and 8.4% of children. asthma is the leading chronic disease in children [3] . this disease has been increasing since the early 1980s in all age, sex, and racial groups. in europe, lung disease represents 15% of all deaths -the fourth leading cause. according to the world health organization (who), in 2008, 9.5 million people died from acute or chronic lung disease, representing one sixth of the global total deaths [4] . worldwide, four respiratory disease categories appear in the top ten leading causes of death in 2010 [5] . specifically, copd was the third leading cause of death, followed by lower respiratory infections as the fourth, lung cancer as the fifth, and tuberculosis as the tenth [4] . the major risk factor is smoking, leading to 50% of all lung disease-related deaths in europe, where smoking is more prevalent (28% prevalence) than in the united states (15% prevalence) by nearly twofold [6, 7] . lung cancer, particularly non-small-cell lung cancer (nsclc) subtype, is the leading cause of cancer-related death worldwide [8] . added together, lung disease rivals the position for the top cause of death. throughout the life cycle, diet and lifestyle are important modifiable risk factors in the development, progression, and management of obstructive lung diseases, such as asthma and copd [9] , as well as restrictive lung diseases such as pulmonary fibrosis and sarcoidosis. inflammation, in particular, seems to be the leading contributor toward the progression of lung diseases. as with many diseases, maintaining a healthy lifestyle, including sufficient sleep, low stress, regular exercise, a whole foods diet rich in phytonutrients from plants (fruits and vegetables), and potential anti-inflammatory supplements, is beneficial in supporting the body during these difficult diseases. inflammation, in particular, seems to be the leading contributor toward the progression of lung diseases. high inflammatory foods should be avoided, such as fried foods and foods disproportionately high in carbohydrates, sugar, alcohol, and excessive protein. a healthier suggestion would be a diet with more than half of all food consumed as vegetables, about one third as protein, and the remainder (one sixth) as other foods, such as fruits, dairy, grains, or starches. some dietary supplements may also be recommended for their anti-inflammatory benefits, which will be discussed later in the chapter. as human life expectancy increases, we can expect to see more chronic disease. the world health organization estimates that by 2030, chronic lung disease will account for 20% (one fifth) of all deaths [10] , up from one sixth in 2008. despite these growing numbers, relatively little human nutrition research exists for respiratory health, compared to other, less prevalent, diseases. investigators in the areas of aging and lung biology suggest some hope, using genetics and animal models, as well as epidemiological research, to further the general medical approach to lung disease. the pulmonary system is composed of the upper and lower respiratory tracts. air flows in through the nose or mouth, past the frontal and maxillary sinuses, down the pharynx (throat), past the larynx (voice box), and then down the trachea. this makes up the upper respiratory tract. once past the trachea, the air divides into the left and right bronchi, which supply the left and right lungs, each divided into five sections called lobes. the bronchi then divide into smaller bronchioles, at the end of which are air sacs called the alveoli. this makes up the lower respiratory tract [11] (. fig. 51 .1). the diaphragm is the central muscle that is used for breathing. the intercostal muscles, located between the ribs, and the abdominal muscles are helpful for breathing out when the breath becomes labored, such as during exercise. the neck muscles and the muscles in the collarbone area help with breathing when the other muscles are compromised or impaired. in some neurological diseases, such as amyotrophic lateral sclerosis (als) [see 7 chap. 51, newton], nerve damage from the brain to breathing muscles can result in impaired movement of these muscles and thus impaired breathing. in certain cases, such as in lung cancer when a lobectomy, removal of part of the lung, is required, there is an expected decrease in short-and long-term pulmonary function and oxygenation. however, respiratory muscle strength may be preserved [13] . in a pneumonectomy, removal of the entire lung, dramatic changes in thoracic anatomy take place, such as elevation of the hemidiaphragm, hyperinflation of the remaining lung, and influx of fluid into the postpneumonectomy space [14, 15] . there are phagocytic macrophages on the cellular surface of the alveoli, type i epithelial cells and type ii epithelial cells. phagocytic macrophages destroy inhaled bacteria and serve an important role in suppressing or activating the immune response to antigens and pathogens, similar to dendritic cells discussed below. macrophage function has been shown to be inhibited by cigarette smoke [16] . alveolar macrophages also secrete enzymes, arachidonic acid metabolites, growth factors, immune response components, cytokines, and lymphocytes [17] . type i cells are responsible for maintaining the structure of the alveolar wall, whereas type ii cells and clara cells are responsible for the production of pulmonary surfactant (composed of 85-90% lipid and 10-15% protein as lecithin and myelin), which is essential for lung function. the surfactant reduces surface tension, facilitating easier stretching and collapsing of alveoli during respiration [18] . diseases associated with inadequate surfactant production are acute/adult respiratory distress syndrome (ards) and infant respiratory distress syndrome (irds) [19] . irds is seen in premature babies born prior to 32 weeks of gestation due to immature development of pulmonary surfactant, which only begins to develop around the 20th week of gestation [18] . dipalmitoylphosphatidylcholine, phosphatidylglycerol, and cholesterol compose the lipid portion of the surfactant, where apoproteins and proteins found in blood plasma compose the protein portion [18, 20] . the importance of cholesterol is minimized in today's medical community. those with higher levels of cholesterol tend to have more in their fatty cell membranes which resist pathogenesis at a cellular level. low cholesterol predicts a greater risk of dying from gastrointestinal, neoplastic, or respiratory diseases. it occupies 30-40% of our cell membranes, enhances the mechanical strength of the membrane, and reduces permeability [21] . it suppresses main-phase transition of the lipid bilayer [22] . collagen, a fibrous protein, along with elastin and proteoglycans, is a fundamental component of the connective tissue that composes the lungs, and collagen is present in the blood vessels, bronchi, and alveolar interstitium [23] . connective tissue in the lung is key for the passive diffusion of oxygen and carbon dioxide that characterizes alveolar-capillary gas [18] . collagen homeostasis is vital to maintaining respiratory function, where collagen production and degradation are balanced. dysregulated collagen homeostasis that favors collagen production over degradation can lead to pulmonary fibrosis and compromised lung function [24] . some key nutrients to consider for collagen synthesis and crosslinking to maintain connective tissue integrity are vitamin c, vitamin b6, iron, copper, zinc [25] , riboflavin, thiamin, and pantothenic acid [11] . the airways of the respiratory system (with the exception of parts of the nose and mouth) have cilia, special hairs coated with mucus that trap pathogens and other particles that enter with the air that is inhaled. cilia are responsible for triggering this mucus upward toward the pharynx where these particles or bacteria can be coughed out or swallowed. mucus present in the lungs can also trap inhaled particles such as viruses, bacteria, and smoke particulates [11, 12] . along the lining of the respiratory tract, there are several types of cells that are involved in immune response, such as secretory cells (i.e., goblet cells and clara cells) and mast cells. ciliated epithelium and mucus secreted by glands present on airways, goblet cells, and the secretory products of clara cells serve an important mechanism for lung protection. however, excessive goblet cells or hypertrophy of mucous glands may result in increased viscosity of mucus seen in pathologies like bronchitis [16] . ciliary function is also impaired by cigarette smoke [16] . dendritic cells are also found in the airway lining from the trachea to the alveoli. immature dendritic cells phagocytize bacteria or other antigens, where they then mature and travel to lymphoid tissues to communicate with the immune system. this delivery of antigens can promote tolerance of the antigen by releasing anti-inflammatory cytokines. conversely, this delivery can also trigger the opposite response if the antigen is recognized as a pathogen, where t lymphocytes are activated and inflammatory cytokines are released [16] . one potential cause of infections in the upper respiratory tract or bronchial tubes, such as bronchitis, or deep in the lungs, such as pneumonia, is when cilia become damaged and do not trap inhaled germs and particles as effectively. in diseases such as cystic fibrosis, thick mucus secretions can accumulate in the airways and lungs, making it hard to clear and thus increasing risk for infection. in asthma, specific inhaled particles can trigger a reaction causing the airways to narrow, restricting breathing [12] . surface enzymes and factors can also be found in the lining of the airways that compose the majority of the innate immune system of the respiratory tract. these include: 5 lysozymes: found in leukocytes with bactericidal properties 5 lactoferrin: a bacteriostatic agent (inhibits bacterial reproduction) synthesized by lymphocytes and glandular mucosal cells 5 alpha-1 antitrypsin: an antiprotease to protect lung tissue from excessive enzymatic activity 5 interferon: an antiviral substance that may be produced by lymphocytes and macrophages 5 complement: participates as a cofactor in antigenantibody reactions [16] gas exchange takes place in the alveoli so oxygen can enter the body to support metabolic function and the carbon dioxide product from these functions can be removed. this is accomplished through millions of capillaries in the alveoli. these capillaries in the alveoli then connect to arteries and veins that move blood throughout the body. the pulmonary artery supplies carbon dioxide-rich blood to these capillaries within the alveoli to remove carbon dioxide, and the oxygen-rich blood then gets delivered to the heart through the pulmonary vein. the lungs also serve the vital function of maintaining acid-base balance through changes in minute ventilation. these changes affect the ph of the blood by either retaining or excreting carbon dioxide [11] . poor physiologic management of co 2 and bicarbonate can lead to the conditions of respiratory acidosis and respiratory alkalosis. respiratory acidosis is characterized by higher blood concentrations of co 2 and h + , caused by hypoventilation or decreased rate of breathing. hypoventilation can have acute or chronic etiologies, resulting from copd, interstitial lung diseases, respiratory muscle fatigue (i.e., extended asthma attack), or mechanical abnormalities (i.e., deformities). respiratory alkalosis is characterized by lower blood concentrations of co 2 and h + due to hyperventilation, or increased rate of breathing. possible causes of hyperventilation can also be chronic or acute, such as pneumonia and fever, increased stress and anxiety, liver disease, stroke or meningitis, pregnancy, overuse of aspirin and/or caffeine, excessive mechanical ventilation, or increases in altitude [18] . a pulse oximeter tool can be used to measure the percentage of oxygenated hemoglobin in an individual's blood to determine their overall respiratory status. typically, oxygen saturations of 92% or less are indicative of central hypoxia [26] . pulse oximetry is especially useful for assessing individuals with asthma and copd [26] . oral health must also be considered as a contributing factor to respiratory health [27] . for example, in patients affected with periodontal disease, 1 mm of dental plaque could contain around 10 9 of bacteria. one potential mechanism of this connection is aspiration of bacteria from the oropharynx into the upper or lower respiratory tracts, leading to their adherence to the alveolar and bronchial lining, potentially colonizing respiratory ducts and causing respiratory infections. in addition, cytokines and enzymes associated with inflammation of periodontal tissues can be transferred into the lungs, potentially triggering or exacerbating lung infections [27] (. fig. 51 . a systematic review done in 2013 examined oral health in the elderly and its association with risk of aspiration pneumonia. this review suggested that maintaining oral health, such as brushing after each meal, cleaning dentures once per day, and professional oral healthcare, potentially reduced the amount of potential respiratory pathogens that resulted in lower incidence of aspiration pneumonia [28] . several other systematic reviews have found that adequate oral hygiene plays an important role in preventing pneumonia, particularly in clinical settings where there is increased risk for hospital-acquired pneumonia (hap) and ventilatorassociated pneumonia (vap), as well as in older populations [29] . in addition, associations have been made between copd and the risk of periodontitis, although systematic reviews have established that these associations are preliminary and further studies are needed [29] . another important consideration in respiratory health is orofacial development and structure. anatomical obstructions at the level of the nose and pharynx, such as those caused by allergic rhinitis and hypertrophy of the tonsils, pose an increased risk for obstructive sleep apnea syndrome and respiratory infections due to lack of airflow through the upper respiratory system [30] . it has been established that the lung has a microbiome of its own that may have a large impact on health and disease [31] . the fungal microbiome, or mycobiome, may also have a significant impact on respiratory health, although more research is needed to determine definitive associations [31] . dysbiosis may occur in the lungs with a bacterial infection. a few specific bacterial strains have been studied, and one, in particular, pseudomonas aeruginosa, seems to grow in inflammatory conditions. it then seems to encode inflammatory components causing further inflammation. anti-inflammatory nutrients could help stop the cycle, and vitamin d use has some research supporting this. recurrent bacterial respiratory infections may damage lungs and lead to worse outcomes in future lung disease [32] . an increased interest in research of the relationship of the airway and gut microbiome is indicating potentially positive results regarding the use of probiotics in pediatric populations that may aid in asthma prevention and intervention [33, 34] . the gut-lung axis has also been established, where the microbiomes of the lung and gut have been immunologically linked and are thought to have an impact on respiratory disease [35, 36] . the autophagy mechanism within our microenvironment provides a constant "cleanup" system to recycle cell debris from microscopic biowaste generated by dynamic cellular biochemistry [37] . enzymes such as neutrophil elastase function like garbage disposals recycling waste molecules. alpha-1 antitrypsin is a thermostat-like control factor that signals the proteolytic enzymes to stop and protect healthy tissue from being affected. antiproteases in the lung, such as alpha-1 antitrypsin, are required to prevent the overactivity of neutrophil elastase to prevent the degradation of healthy lung tissue. those with the genetic mutations of a1at deficiency are at disadvantage, and subsequent lung tissue damage can occur promoting lung diseases like copd, asthma, bronchitis, and emphysema. key components of lung structure are elastin and collagen, which provide support for the bronchioles and clusters of alveoli (acini). the key enzyme present in these cells is neutrophil elastase, which is responsible for the destruction of respiratory bacteria. protease and antiprotease imbalance in the lung resulting in emphysema can be caused by alpha-1 antitrypsin deficiency and nicotine in cigarette smoke or polluted inhalant exposure [18] . ifmnt approaches to the a1at-deficient patient assess for nutrient insufficiencies for some of the important connective tissue, collagen, and elastin system key nutrients: vitamin c, vitamin d, biotin, balanced fatty acids, and gut microbiome. when insufficiencies or deficiencies are identified, appropriate food and dietary supplementation interventions can be recommended. it should be noted that if an individual is identified with a1at deficiency genotype, the status of liver health should also be assessed, as a1at pathophysiology can express in liver cirrhosis. more recent studies of respiratory disease [38] have revealed the relationship with bacterial or viral infections exacerbating the individual's genotype eliciting expression of the associated diseases. one of the most recognized inherited conditions of altered autophagy mechanisms is alpha-1 antitrypsin deficiency, with 80-100 genetic variants affecting severity of lung expression. low levels of circulating a1at allow potentially harmful enzymes like neutrophil elastase to remain in the lungs unchecked. low levels of a1at, and the consequent proliferation of neutrophil elastase, leave lung tissue vulnerable to destruction, resulting in a decline in lung function. there are several categories of lung disease and many diseases within those categories (. table 51 .1). some micronutrients and phytonutrients have important antioxidant and methyl-donating properties important for the lungs and therefore have great role in a nutritional approach to lung health. iron's interaction with the lungs is essential. it carries oxygen from the lungs to the peripheral parts of the body, as well as carbon dioxide back to the lungs to be exhaled. however, too little or too much iron can pose a problem for the lungs. before iron administration, it is important to rule out hemochromatosis, or iron overload, for an individual. iron-deficiency anemia often presents in many chronic diseases including those of the lung, such as copd, lung cancer, and ipf [57] . increased mortality, decreased quality of life, increased hospital admissions, and cost of treatment have been reported for those with chronic disease and low iron [58] . anemia of chronic disease (acd) is usually at the root of this. acd is often the result of inflammation. inflammatory proteins, including il-6, stimulate the production of hepcidin in the liver, which inhibits absorption and increases storage of iron resulting in a functional iron deficiency. typical iron markers, such as transferrin saturation, total iron binding capacity (tibc), and ferritin, are also affected by inflammation and are less useful markers in chronic disease. soluble transferrin receptor (stfr) seems to be a lesser known marker that is less affected by inflammation [59] . because of the difficulty with iron absorption, intravenous iron is often used to replete deficiencies. as iron is a pro-oxidant, researchers studied any negative repercussions. there does not seem to be any increased oxidative stress with intravenous iron, but glutathione, the body's endogenous super antioxidant, does seem to decrease, likely in response to the pro-oxidative activity of iron. in a recent study, administration with vitamin e was seen to eliminate these negative effects [57] . excessive iron can also be problematic for lung health for those with the genetic mutation for hemochromatosis (hfe). disorders of iron overload are increasingly being recognized as risk factors for most of the chronic diseases like cardiovascular, alzheimer's, and cancer [60] . high iron can catalyze the formation of highly reactive hydroxyl radicals, oxidative stress, and programmed cell death. in the instance of lung cancer and other cancers affecting the lungs, tumors sequester iron for their own growth, usually leaving the patient with iron-deficiency anemia. in fact, 90% of cancer patients undergoing chemotherapy are iron deficient. inflammation also plays a role in iron homeostasis. the pro-inflammatory cytokines cascade down to affect the proteins that regulate . chronic obstructive pulmonary disease (copd) disease that restricts airflow through either inflammation of the lining of the bronchial tubes or destruction of alveoli increased risk of emphysema if genetic variant of alpha-1 antitrypsin deficiency and smoking or exposed to high levels of air pollution [11] bronchiectasis a disorder of the airways that leads to airway dilation and destruction, chronic sputum production, and a tendency toward recurrent infection [39] bronchiolitis airway injury that can be caused by infections, irritants, toxic fumes, drug exposures, pneumonitis (typically viral), organ transplants, connective tissue disorders, vasculitis, or other insults [40] dyspnea shortness of breath or difficulty breathing [11] emphysema thinning and destruction of the alveoli, resulting in decreased oxygen transfer into the bloodstream and shortness of breath. increased risk of emphysema if genetic variant of alpha-1 antitrypsin deficiency and smoking or exposed to high levels of air pollution [11] alpha-1 antitrypsin deficiency a deficiency of a1at, a protein produced in the liver that protects the lungs from excessive neutrophil elastase, an autophagic enzyme. a1at may also accumulate in liver and cause liver disease [55] obstructive asbestosis fibrotic lung disease resulting from extensive inhalation of asbestos fibers [42] desquamative interstitial pneumonitis (dip) form of idiopathic interstitial pneumonia that is more common in cigarette smokers but may be seen in nonsmokers, in patients with underlying connective tissue diseases or those exposed to inorganic dust/particles [43] sarcoidosis immune-mediated systemic disorder that is characterized by granuloma formation of the lung parenchyma and the skin [44] restrictive pathophysiologyneuromuscular weakness amyotrophic lateral sclerosis (als) progressive neurological disease that affects the motor neurons of the nervous system [11] guillain-barre syndrome progressive immune system attack on the peripheral nerves, usually following an infectious illness such as a respiratory infection. may eventually cause respiratory distress syndrome [11] restrictive pathophysiologychest wall/pleural disease kyphoscoliosis kyphoscoliosis: a deformity of the thoracic cage that results in restriction of the lungs and impairs pulmonary function [45] ankylosing spondylitis autoimmune inflammatory disorder characterized by inflammation of the axial skeleton and peripheral joints [46] chronic pleural effusions chronic accumulation of fluid between the two outer membranes surrounding the lungs [11] pulmonary vascular disease pulmonary embolism blood clot that typically originates from thrombi in the deep venous system of the legs and travels to the lungs pulmonary arterial hypertension (pah) progressive disorder of primary pulmonary arterial vasculopathy characterized by a mean pulmonary arterial pressure >25 mm hg at rest (>30 mmhg during exercise) [48] iron homeostasis [61] . iron can also impair cytokine secretion, which can leave those with an iron overload much more susceptible to infection, increasing the morbidity and mortality of infectious diseases, including those of the lung [59] . oxidative stress may contribute to injury of lung tissue, causing further fibrosing in those lung diseases with that characteristic. allele variants in the genes associated with iron homeostasis (c282y, s65c, and h63d hfe) are significantly more common in those with idiopathic pulmonary fibrosis (ipf) than those without ipf (40.4% ipf patients vs 22.4% non-ipf) and are associated with higher irondependent oxygen radical generation [62] . iron is implicated in lung pathology. monitoring iron status and using supplements or diet to aid the body in increasing or decreasing the iron load are imperative for the nutritionist working with lung disease patients. choosing a good non-constipating form of iron is important, such as iron glycinate. the b vitamins are also important to monitor for lung health. vitamin b6 and its bioactive form, p-5-p, are typically known to protect dna from mutation or damage [63] . however, there is mixed evidence on its role for lung cancer. some research has shown that it is helpful for lung cancer patients as it is important for apoptosis when using chemotherapy, because it sensitizes cancer cells to apoptosis [63] . however, research in 2017 showed that adult male smokers taking greater than 20 mg vitamin b6/day for long periods tended to have a greater risk for lung cancer. many variables, including genetic variants, form of b6, and the status of other co-nutrients may be at play [64] . other studies showed that men in the top quintile of vitamin b6 serum concentration had about one half the risk of lung cancer, and specifically, vitamin b6 and folate were inversely associated with risk of lung cancer [65] . . squamous cell (epidermoid) carcinoma about 25-30% of all lung cancers. these start in early versions of squamous cells, which are flat cells that line the inside of the airways in the lungs. often linked to a history of smoking and tend to be found in the central part of the lungs, near the bronchus [50] large cell (undifferentiated) carcinoma about 10-15% of lung cancers. it can appear in any part of the lung and tends to grow and spread quickly. a subtype of large cell carcinoma, known as large cell neuroendocrine carcinoma, is a fast-growing cancer that is very similar to small-cell lung cancer [51] small-cell lung cancer (sclc) about 10-15% of lung cancers are sclc. typically start in the cells lining the bronchi and parts of the lung such as the bronchioles or alveoli [52] infectious diseases pneumonia inflammation of the lungs, usually caused by bacteria, viruses, or fungi [11] bronchitis inflammation and eventual scarring of the lining of the bronchial tubes accompanied by restricted airflow, excessive mucus production, and persistent cough [11] tracheitis bacterial infection that can develop in the trachea [53] infant respiratory distress syndrome also known as hyaline membrane disease (hmd) or respiratory distress syndrome, this condition affects the alveolar ducts and terminal bronchioles in which the hyaline membrane is a fibrinous material composed of blood and cellular debris, caused by the absence of proper surfactant production due to an immature or poorly developed lung [54] upper respiratory infection (uri) acute infections involving the nose, sinuses, pharynx, larynx, trachea, and bronchi, referred to as the common cold [11] bronchopulmonary dysplasia (bpd) chronic lung disorder which may affect infants who have been exposed to high levels of oxygen therapy and ventilator support [11] other cystic fibrosis disease characterized by abnormally thick mucus secretions from the epithelial surfaces of many organ systems, including the respiratory tract, the gastrointestinal tract, the liver, the genitourinary system, and the sweat glands [11] acute lung injury clinical and radiographic changes in lung function associated with critical illness (acute respiratory distress syndrome is most severe form) [11] respiratory because of disagreement in research, particularly with smokers or former smokers, using food first for b vitamins may be a prudent way forward. good sources of vitamin b6 are fish, chickpeas, chicken, potatoes, turkey, bananas, ground beef, and winter squash. pyridoxal kinase (pdxk) is the enzyme that converts pyridoxine and other vitamin b6 precursors to its bioactive form of p-5-p. dysfunction of this enzyme is a good prognostic for lung cancer and other lung diseases. mthfr 1298aa genotype is associated with a higher risk of lung cancer in women but not in men. the mthfr 677tt genotype was associated with a significantly decreased risk of lung cancer in women but not in men. in contrast, the mthfr c677t and a1298c polymorphisms interacted with smoking status in men but not in women [66] . methylation gene testing is imperative to understand the patient's status. some studies suggest that a higher intake of riboflavin (vitamin b2) may protect against lung cancer in smokers [67] . folate deficiency was also associated with asthma and attacks of shortness of breath [8] . correcting acidosis may preserve muscle mass in diseases where wasting is an issue, such as copd or ipf. for those receiving chemotherapy, a higher ph (more alkaline status) is helpful for muscle mass protection. high alkaline diets contain more fruits and vegetables, and those supply more magnesium, which is needed to activate vitamin d. as discussed below, vitamin d is extremely helpful for lung health. sleep quality involves maintaining adequate 7-8 hours with good sleep hygiene (see 7 chap. 34). good rem cycling, feeling refreshed upon awakening, and other characteristics of good sleep play significant roles in maintaining healthy acid-base balance. dietary intake of the minerals magnesium, potassium, sodium, chloride, and calcium promotes the balance of acidbase microenvironment. after exposure and tissue retention of toxic minerals and metals, these substances can contribute to perturbations in the acid-base metabolic milieu. some conditions reduce oxygen intake and should be addressed. one of the most common oxygen-impairing conditions is sleep apnea, altered sleep with random halting of breathing during sleep that is often accompanied by snoring. other limiting conditions are respiratory diseases like copd, a1at deficiency, asthma, cystic fibrosis, etc. vitamin a is an important antioxidant and a general umbrella term for several fat-soluble retinoids, including retinol, retinal, and retinyl esters. there are also other substances that are provitamin a carotenoids or precursors to vitamin a. two forms are found in foods, the preformed forms of retinol or retinyl esters, which are found in dairy, fish, caviar, and meats (especially liver), and the provitamin a carotenoids, including the most important and common provitamin a carotenoid, beta-carotene, as well as others including alpha-carotenes and cryptoxanthin, which are found in plant-based foods. our bodies must convert these two forms within our cells to retinal and retinoic acid, the active forms of vitamin a in the body. new studies of the gene, β-carotene 15,15′-monooxygenase (bcmo1), which is responsible for the enzymatic conversion of β-carotene to vitamin a, are revealing that individuals with heterozygous or homozygous bcmo1 snps have 30-60% less efficient conversion than those with normal gene function (see 7 chap. 17) [68] . other carotenoids found in food, such as lycopene, lutein, and zeaxanthin, are not converted to vitamin a but have other antioxidant benefits in the body. most vitamin a is stored in the liver as retinyl esters, and deficiency is not visible until these stores are nearly depleted. vitamin a's role as an antioxidant helps the lungs in several ways, including maintaining alveolar epithelium cells and preventing development of respiratory tract infections. most of the developed world's population does not have a risk of deficiency due to sufficient vitamin a intake. however, most people with cystic fibrosis have pancreatic insufficiency, which reduces the ability to absorb fat and therefore the fat-soluble vitamins a, d, e, and k. according to a study in 2002, between 15% and 40% of people with cystic fibrosis had a vitamin d deficiency, also a fat-soluble vitamin. with the addition of pancreatic replacement treatments, better nutrition, and vitamin a supplementation, deficiency has become rare. however, improved vitamin a status has not been thoroughly studied as of 2018, and therefore it is largely unknown if an improved vitamin a status has any effect on cystic fibrosis [69] . vitamin a deficiency has been shown to be associated with emphysema in rats. smoke exposure significantly decreases vitamin a concentration in lung tissue, significantly more in those with copd [70] . retinoic acid seems to play a beneficial role in the treatment of ipf. a review showed that in all studies, retinoic acid decreased fibrosing, the formation of collagen, and reduced the expression of alpha-smooth muscle actin (alpha-sma), all hallmarks of ipf [71] . it is important to not take large doses of vitamin a if one is in a malnourished state as it can cause toxicity and should be monitored with blood testing of vitamin a retinol. nourish the body with all foods and all nutrients slowly. the non-provitamin a carotenoids have also shown some benefit. lycopene, found in high amounts in guavas, watermelon, tomatoes, papaya, grapefruit, sweet red peppers, asparagus, purple cabbage, mangos, and carrots, slowed forced expiratory volume (fev) decline in former smokers [70] . vitamin d's importance with lung health cannot be understated. vitamin d deficiency, or even insufficiency, is linked to accelerated decline in lung function, increased inflammation, and reduced immunity in chronic lung diseases. vitamin d has a role in the regulation of inflammation, immunity, cellular proliferation, senescence, differentiation, and apoptosis. sufficient vitamin d levels are correlated with better asthma control, better immune response related to respiratory infections, and reduced severity of exacerbations with copd and asthma when exposed to inflammation-causing pathogenic activity [72] . vitamin d is obtained through sunlight on the skin (without sunscreen) and very few dietary sources. therefore, supplementation is generally recommended. higher vitamin d levels are shown to be protective in many lung disease states. sufficient levels improve treatment response with medications and reduce asthma severity [68] . with infectious diseases of the lung, higher vitamin d concentrations are shown to have a protective action [6] . vitamin d has a protective effect on lungs of smokers, and higher levels of vitamin d inhibit the pro-fibrotic phenotype of lung fibroblasts and epithelial cells. current data suggest an inverse association between serum vitamin d and lung cancer risk, and vitamin d deficiency at 16-20 weeks' gestation is associated with impaired lung function and asthma at 6 years of age [73] . lower levels of vitamin d are associated with an increased risk for respiratory infections, cystic fibrosis, chronic obstructive pulmonary disease, and interstitial lung disease [74] . vitamin c is an important antioxidant that helps decrease oxidative damage in the body, including in lung tissue. it is also essential for lipid metabolism. it is present in the airway surface liquid and creates an interface between the epithelial cells and the external environment. vitamin c is a cofactor in collagen synthesis, which can aid in repair of bronchial and alveolar tissue when damaged. it also provides beneficial control of lipid peroxidation of cellular membranes, including those surrounding as well as those within intracellular organelles. vitamin c has some of the best lung protective capabilities, according to current research. vitamin c may also diminish oxidative attack on nonlipid nuclear material and is an antioxidant component of plasma and extracellular fluids surrounding the lungs. it is an antioxidant that not only fights oxidative stress but also reduces oxidized vitamin e and glutathione, allowing them to become active as antioxidants again. vitamin c is antiinflammatory and is helpful in all inflammatory states of the lung, even allergies. there are many ways in which vitamin c, along with its antioxidant partners, glutathione, vitamin e, vitamin a, and plant-based phytonutrients, affects lung health. it is well established that increased levels of vitamin c in the diet improve health outcomes for smokers and their offspring, as smoking depletes vitamin c [75, 76] . vitamin c is also helpful in fighting infectious diseases such as respiratory infections and pneumonia, copd regardless of smoking status, asthma, and lung cancer [77] . specifically, in certain lung cancers, vitamin c, along with other nutrients such as lysine, proline, epigallocatechin gallate, and zinc, can inhibit the proliferation of certain carcinoma lines and induce apoptosis, as well as inhibit lung cancer metastasis [78] . even in lung transplants, vitamin c is helpful against oxidative stress by reducing glutathione and lowering lipid peroxidation, along with vitamins a and e [79, 80] . the literature suggests these benefits can be achieved at 500-3000 mg/day. check iron status before administering vitamin c supplementation as vitamin c doubles iron absorption from foods. vitamin e's primary role is as an antioxidant, breaking free radical chain damage and preventing peroxidation of lipid molecules. this vitamin also is promising with regard to beneficial effects on lung function preservation. oxidative stress and inflammation are key features in many lung diseases; therefore nutrients with antioxidant capacity can be useful. a few studies suggest that alpha-tocopherol found in sunflower and olive oils has a beneficial effect on fev (forced expiratory volume), whereas gamma-tocopherol found in canola, soybean, and corn oils has a negative effect on fev [81] . however, from these authors' perspective, this is likely due to the source and type of the oils, which can be inflammatory, rather than the form of vitamin e. for example, a recent study showed that gamma-tocopherol was protective in allergic asthma [82] . in addition, sufficient levels of vitamin e, in the alpha-tocopherol form, were found to reduce susceptibility of the elderly to acquiring pneumonia. some of the positive effects of vitamin e are synergistic with vitamin c [83] . phytonutrients have been found to have two effects with respect to lung disease: one is a symptom-improving pattern, and the other is a rate-reducing pattern [84] . idiopathic pulmonary fibrosis (ipf) is largely characterized by reduced antioxidant and increased inflammatory action. recent literature is showing the ability of certain flavonoids, in particular quercetin, to reduce inflammation and act as a strong antioxidant countering the pro-oxidant environment of ipf. quercetin is recognized as the most potent ros scavenger. taken together with glutathione, the impact is even greater, and it seems to help improve the antioxidant and inflammatory status more for those with ipf than non-diseased controls [85] . curcumin has been shown to slow or limit fibrosing in murine studies related to lung, liver, or kidney fibrosing [86] [87] [88] [89] . it has also been shown to attenuate metastatic melanoma in the lungs when delivered in a nanoparticle [90] . the potential for curcumin is interesting and hopeful. fisetin and fenugreek have also been studied as useful phytonutrients that help combat inflammation in lungs [91, 92] . fisetin is found in apples, strawberries, persimmons, cucumbers, and onions, among many other fruits and vegetables. fenugreek is a plant used frequently in south and central asian cooking, where both the seeds and leaves are used. there are now supplements available for both of these phytonutrients. this is a reminder to eat a primarily plantbased diet when combating inflammation and to broaden our palates to include healthy foods and ingredients from other cultures than our own. lastly, the powerful antioxidant cannabidiol (cbd), from the cannabis and closely related hemp plants, is a powerful shield against oxidative stress, prevalent in lung disease [93] . the research is not robust regarding lung function and minerals, and most has been done with regard to cystic fibrosis where bone density is associated with general nutritional status, including minerals. there have also been many studies trying to determine a correlation between mineral status and copd, where, again, the research shows that mineral status is not predictive but overall nutrient status may fall if not monitored. in contrast, one study in japan showed an inverse association between dietary calcium and the risk for copd [94] . in an nih-aarp diet and health study, magnesium, iron, selenium, zinc, and copper intakes, both dietary and supplemental, were studied with respect to lung cancer. mineral supplementation did not affect lung cancer risk, yet dietary intake of calcium, along with vitamin d, and iron reduced the risk, and dietary intake of magnesium increased risk [95] . boron has been shown to be protective against lung cancer, along with other nutrients, at levels of 3 mg/day [96] . there is some research showing that selenium is helpful, particularly for smokers, for improved fev. higher magnesium status is correlated to better fev but is not yet seen as an association. this may be due to magnesium's role as the vitamin d activator. there have been a few studies showing increased copper levels are related to decreased fev. some recent research has also shown that dietary zinc and iron are associated with reduced lung cancer, but the same was not seen with calcium, copper, magnesium, or selenium [97] . low mineral bone density is prevalent at a higher rate among cystic fibrosis patients, and therefore supplementation with vitamin d, vitamin k2, magnesium, calcium, and the trace minerals can be helpful [98] . alpha-lipoic acid (ala) is a powerful antioxidant endogenously produced in the human body from foods such as yeast, organ meats, spinach, broccoli, and potatoes and is both water-and fat-soluble. ala, along with n-acetyl cysteine (nac), glycine, and vitamin c, is an important precursor to glutathione, which is a powerful endogenous antioxidant and the primary antioxidant in the lungs. ala has been shown to be anti-inflammatory in lung tissue in those with acute lung injury, and the proposed action is via inhibition of the nf-kappab signaling pathway [99] . ala has also been shown to downregulate some cancerpromoting actions prevalent in lung cancer, likely by this same pathway [100] . it also may alleviate nicotine-induced lung oxidative stress [101] . n-acetyl cysteine (nac), another precursor to glutathione, is a powerful antioxidant on its own as well. in relation to the lungs, nac helps the clearance of mucus in the lungs by pulmonary cilia. this has been shown to be effective at 400-600 mg/day in divided doses [102] . there is significant research on nac and lung health, showing improvement with nearly all lung issues, including nearly 40 studies showing improvement for bronchitis [103] , infectious diseases by reducing the bacterial count [104] , smokers, and people with asthma and copd, through both its antioxidant effects and by reducing the viscosity of sputum and mucus. at an oral dose of 1800 mg/day, the mean glutathione concentration in lung tissue increased by 49% on one study [105] . there are additional studies showing improvement for those with copd, asthma, cystic fibrosis, pulmonary fibrosis, and symptoms related to allergies or other infections. the dose that has been studied and has been shown to be most useful is 600 mg twice daily and more effective if nebulized [106, 107] . both ala and nac supplementation should be accompanied by vitamin b6 and the complex of b vitamins to prevent an elevation in liver enzymes (. fig. 51 .3). there are several specialty labs that conduct micronutrient analysis and functional testing, such as genova diagnostics and spectracell. these tests can be useful for evaluating levels of individual nutrients as they function in the body, rather than just in serum, which is not an accurate indicator of tissue or functional status. patients suffering from copd, interstitial lung disease, and other diseases tend to have muscle and weight loss related to respiratory acidosis, and increasing weight and muscle mass helps with quality of life. respiratory acidosis occurs with co 2 buildup where the lungs are no longer able to effectively exchange o 2 and co 2 . nutritional supplementation should attempt to reduce metabolic co 2 production. fat metabolism produces less co 2 than carbohydrate metabolism, so emphasizing a higher fat, lower carbohydrate diet can be helpful [110] . in general, a high intake of omega-6 fatty acids is associated with poorer forced expiratory volume (fev) in patients with lung disease because of their pro-inflammatory nature. however, a complete fatty acid panel or a red blood cell membrane fatty acid test would reveal more details about the status of an individual's omega-6 pathway. certain omega-6s and the work of their corresponding metabolizing enzymes such as elongase and delta-5 or delta-6-desaturase may allow healthful omega-6s (linoleic (la), gamma-linolenic (gla), lipoxins [111] , prostaglandin 1 series metabolites) to flow down an anti-inflammatory pathway instead. important cofactors for this pathway are vitamin b2, vitamin b3, vitamin b5, vitamin b6, biotin, vitamin c, zinc, and magnesium. lipid metabolism dysregulation is understood to be part of the pathogenesis of idiopathic pulmonary fibrosis. in ipf, free fatty acids play a role in the proliferation of fibroblasts. certain fats, in particular palmitic acid, oleic acid, and linoleic acid, are elevated in the lungs of those with ipf, whereas stearic acid is low. stearic acid is found in meat, poultry, fish, grain products, and milk and milk products. the palmitic, oleic, and linoleic acids enhance the tgf-ß1-induced expression of α-smooth muscle actin (sma) and collagen type 1 in mrc-5 cells, which can lead to fibrosis. stearic acid inhibits the levels of these fibrosing cells. stearic acid also improves the thrombogenic and atherogenic risk factor profiles [112] . in one study on patients with copd, omega-3 fatty acids were found to reduce inflammation in bacterial infections of the lungs without suppressing the ability to clear the bacteria. those taking epa, dha, ala, and gla had improved exercise capacity and had lower risk of developing copd [113] . although results have been mixed over the years possibly due to doses used in studies, a recent 2018 prospective study showed that pufas (omega-3s) from fish help prevent lung cancer and can be part of treatment during lung cancer. in general, the strongest evidence for improved lung function and slowing decline is with the epa and dha forms of omega-3 fatty acids [114] . because of toxicity issues in fish, increasing quality supplements vs fish intake may be more prudent. protein is essential for all lung conditions, and lack of it can result in poorer pulmonary function, decreased exercise capacity, and increased risk exacerbations. since many lung diseases have oxidative stress as a characteristic, it can cause protein carbonylation which may negatively affect dna expression and lipid membranes. nutritional supplementation with added protein and healthy carbohydrates can increase body weight and muscle strength and improve quality of life. those with copd, interstitial lung diseases, and others that affect oxygen absorption and co 2 exhalation have greater levels of hypoxia and sometimes respiratory acidosis, which exacerbates the loss of muscle through oxidative stress and inflammation. supplementation of free essential amino acids versus complete proteins has been shown to help prevent muscle wasting among copd patients. muscle-building exercise is often prescribed for those with copd and interstitial lung diseases [115] . supplemental l-carnitine at 2-6 g/day for 1-2 weeks increased the capacity of copd patients to rehabilitate and build muscle and helped inspiratory muscle strength. carbohydrates should be monitored for sufficient but not excessive levels. more co 2 is produced with the utilization of carbs versus fats for energy. therefore, with gas exchange being an issue with most lung disorders, a slightly higher fat and lower carbohydrate diet may be indicated. it is worth mentioning fiber for a moment, as it is mostly delivered in carbohydrate-rich foods. there is evidence that consuming whole fruits and vegetables higher in dietary fiber is associated with reduced severity of asthma and copd [116] . a diet that derives its carbohydrates from vegetables and fruits rather than from processed carbohydrates such as grains, breads, pasta, or added sugars will deliver fewer carbohydrate grams. glutathione (gsh), a tripeptide composed of cysteine, glutamine, and glycine and produced from methionine, is in every cell in the body. it is the most powerful and abundant endogenous antioxidant in the airway epithelial lining and is responsible for detoxification of electrophilic compounds, the scavenging of free radicals, and modulation of cellular processes such as dna synthesis and repair, differentiation, apoptosis, and immune function [117] . it is also a heavy metal chelator. it is more effective than some other antioxidants because it is intracellular and extracellular. in isolated type ii alveolar epithelial cells, extracellular glutathione inhibits hyperoxia-induced injury, inhibits pro-inflammatory cytokine release, and promotes cell growth. it is obviously very important to maintaining lung function as this is the inflammatory process that begins lung cell or tissue damage, as mentioned above. the highest levels of glutathione concentrations in the body are in the lungs, liver, and brain. gsh depletion leads to activation of nf-kb (pro-inflammatory signaling) and increased pro-inflammatory gene transcription and cytokine release from histone deacetylase suppression in epithelial cells. total and reduced gsh concentrations are much lower in people with ards, pulmonary fibrosis, and hypersensitivity pneumonitis than observed in healthy adults. alterations in alveolar and lung gsh metabolism are widely recognized as a central feature of many inflammatory lung diseases such as idiopathic pulmonary fibrosis, acute respiratory distress syndrome, cystic fibrosis, and asthma [118] . we make glutathione in the body with cysteine and methionine, and it is difficult to take exogenously because digestion can destroy it. the precursors of cysteine (essential), glutamine, and glycine and cofactors (vitamin c, vitamin e, vitamins b1, b2, b6, and b12, folate (b9), minerals selenium, magnesium, and zinc, and alpha-lipoic acid, see below) are therefore recommended so that the body can produce it on its own. the two enzymes necessary to produce it, gamma-glutamylcysteine synthetase and glutathione synthetase, must also be functioning well. we also recycle glutathione if the precursors and cofactors are available. cysteine is usually the most rate-limiting precursor, and many people supplement with n-acetylcysteine to provide the body with this nutrient. although glutathione is produced in every cell of the body, the greatest production is in the liver, so focusing on liver health is important to maintain good glutathione production. production declines with age and with lung disease, as well as other conditions. there are very few foods containing glutathione; they are raw or very rare meat, especially liver, unpasteurized milk and other unpasteurized dairy products, and freshly picked fruits and vegetables, such as avocado and asparagus. however, as mentioned earlier, it may be destroyed during digestion. glutathione contains sulfur molecules, which may be why foods high in sulfur help to boost its natural production in the body. these foods include: 5 cruciferous vegetables, such as broccoli, cauliflower, brussels sprouts, and bok choy 5 allium vegetables, such as garlic and onions 5 eggs 5 nuts 5 legumes 5 lean protein, such as fish and chicken other foods and herbs that help to naturally boost glutathione levels include: 5 milk thistle (a liver-regenerating herb) 5 flaxseed 5 guso seaweed 5 whey glutathione is also negatively affected by insomnia. getting enough rest on a regular basis can help increase levels. addressing a drop in glutathione for lung health involves maintaining good levels of the precursors and cofactors mentioned above. a good way to bring in the less abundant amino acid cysteine is to take n-acetylcysteine (nac). doses of 400-600 mg were more effective than placebo in reducing symptoms [117] . supplemental selenium can also help with glutathione production. glutathione supplementation has also become more effective. there are several forms, from capsules to topical liposomal, which have shown good absorption. inhaled gsh has good research for use in cystic fibrosis (cf), chronic otitis media with effusion (ome), hiv seropositive individuals, idiopathic pulmonary fibrosis (ipf), and chronic rhinitis. it is not recommended for asthma due to significant side effects, and additional evidence is needed to determine if use with emphysema is recommended although theoretically it should be useful. it is also not recommended to use inhaled gsh during cancer chemotherapy treatment as it may interfere with the medication's actions. the mechanism of action of inhaled glutathione is limited to the upper airways and lungs and does not seem to affect serum levels. before considering inhaled gsh treatment, the patient should undergo urine sulfite sensitivity testing using a readily available special test strip called "em-quant 10013 sulfite test. " if positive, inhaled gsh should not be used as bronchoconstriction may occur. the recommended dose is 600-5000 mg per day, depending on response, and whether inhaled gsh is considered safe. efficacy should be tested using a baseline pulmonary function test and a follow-up test after a prescribed time later [119] (. fig. 51 .4, 7 box 51.1). there are also serum tests for glutathione levels. these cofactors are vitamin c; vitamin e; vitamins b1, b2, b6, and b12; folate (b9); minerals selenium, magnesium, and zinc; and alpha-lipoic acid. what do the glutathione cofactors do that makes them so important? 5 direct cysteine toward glutathione production and increase cellular uptake of cysteine 5 help form the glutathione molecule out of the three precursor amino acids 5 help recycle glutathione from its oxidized gssg form back to its reduced (active) gsh form 5 help maintain glutathione levels and keep the gssg-gsh ratio balanced 5 recycle each other, improving overall antioxidant activity 5 stimulate the activity of the whole glutathione enzymatic system co10 is a fat-soluble compound produced endogenously and also available through food and supplementation. it is required in the production of atp, is a powerful antioxidant, and therefore is helpful against oxidative stress, an important issue in lung disease. coq10 achieves its strong effects through a set of different mechanisms. it influences genes through its epigenetic effect to reduce inflammation, helps with the immune system, and even reduces aging by reducing systemic oxidative stress and mitochondrial aging [120] . lungs are the most susceptible organ to oxidant damage because they interact directly with oxygen. therefore, it makes sense that antioxidants, and those that especially affect the lungs, are helpful in tissue and lung cell preservation [121] . coq10 levels are significantly lower in those with copd and asthma with insignificant amounts of research on the levels of coq10 with other lung issues. it has been shown that supplementing patients with coq10 resulted in measurable benefits. in one study, patients with copd using steroids to reduce inflammation were able to reduce their steroid dosage when using coq10 [122] . in another study, benefits were shown for copd patients during exercise, measuring performance, tissue oxygenation, and heart rate at a low dosage of 90 mg/day [123] . the levels of coq10 in the blood have been shown to indicate the degree of systemic oxidative stress, which implies it could be used as a marker to assess copd [121] . several studies confirm the beneficial role of coq10 in decreasing oxidative stress, cardiovascular risk, and modulating inflammation during aging. dosage levels of 1200 mg/ day of coq10 have been shown to be therapeutic. however, in the reduced, more absorbable form, ubiquinol, 400 mg/ day, was shown to be as effective. there is a wide range of toxins and anti-nutrients that can significantly impact the respiratory system. this can occur through acute or chronic exposure to these agents. the earth's air is the source of oxygen, and the lungs provide access to that oxygen to support life. the human need for oxygen is precarious because humans can only survive for about 6 minutes without the precious gas. from about 1760 to sometime between 1820 and 1840 in europe and the united states, the ramp-up of new industrial revolution manufacturing processes opened a new era of increasing chemical and heavy metal atmospheric contamination. these pollutants can enter the body through breathing the polluted air. the more concentrated atmospheric pollutant densities cluster around areas of dense population. the dirty air provides a serious direct threat to those with respiratory diseases. an integrative and functional approach to assessing an individual with respiratory disease needs to include consideration of potential environmental contributors to the etiology of a condition. . table 51 .2 lists environmental pollutants that are known to promote lung pathology. a 2016 study published in the canadian respiratory journal examined exhaled fractional nitric oxide (feno)an indicator of inflammation in the lungs -in school children at three different schools located three different distances from a large steel mill [127] . steel processing is known to be a source of ambient iron, nickel, lead, copper, vanadium, and zinc. the study found statistically significant differences in feno between the two closer schools compared to the farthest school from the mill, indicating potential increased lung inflammation caused by heavy metals and/or air pollutants [127] . although acute metal toxicity is possible, chronic, low-grade exposure is more common and may contribute to respiratory complications and disease. an individual's ability to vitamin c -as an antioxidant, it assists glutathione in this function and has been shown scientifically to raise glutathione levels short term; it is recycled by glutathione from its oxidized state back to its active state, thus strengthening antioxidant defenses; vitamin c also recycles vitamin e and alpha-lipoic acid vitamin e -as an antioxidant it also assists glutathione in eliminating free radicals much like vitamin c; it is also required for the proper functioning of glutathione enzymes; it recycles vitamin c and alpha-lipoic acid b vitamins -vitamins b1 and b2 maintain glutathione and its enzymes in their active forms; vitamin b2 participates in the formation of a glutathione molecule; vitamin b6 influences glutathione synthesis indirectly as it is important for the proper functioning of amino acids including gsh precursors; vitamin b6 increases the amount of magnesium (a vital cofactor) that can enter cells; folate (b9) pushes cysteine toward glutathione production rather than homocysteine production; folate and vitamin b12 work together in amino acid metabolism and protein synthesis. you can read more vitamin b12 deficiency and its effect on immune health at 7 http://www. immunehealthscience. com/vitamin-b12-deficiency. html selenium -part of the enzyme glutathione peroxidase (gpx). glutathione peroxidases, also known as selenoproteins, are a family of antioxidant enzymes that speed up the reaction between glutathione and free radicals magnesium -required for the proper functioning of the enzyme gamma-glutamyl transpeptidase (ggt) involved in the synthesis of glutathione zinc -zinc deficiency reduces glutathione levels, especially in red blood cells. however, zinc levels above normal have pro-oxidant properties and reduce glutathione too alpha-lipoic acid -an antioxidant produced by the body; it has been scientifically proven to enhance and maintain glutathione levels by stimulating enzymes involved in the synthesis of glutathione; it also helps increase the cellular uptake of cysteine, the crucial building block of glutathione; in addition, alpha-lipoic acid recycles vitamins c and e based on data from ref. [124] eliminate these metals via detoxification in conjunction with gastrointestinal health and other factors can serve as important factors in whether or not these metals accumulate in the body. chronic arsenic exposure may be linked to respiratory complications [128] . chronic arsenic ingestion via contaminated drinking water may be connected to respiratory symptoms such as chronic cough, shortness of breath, blood in sputum, and abnormal breath sounds [129] . arsenic can also be ingested through foods such as rice and rice products, shellfish, and seaweeds, which have been shown to have high levels of inorganic arsenic (more toxic than organic arsenic found in fish) [120] . however, ingested inorganic arsenic is typically biotransformed and excreted in the urine [130] . that said, altered biotransformation has been observed depending on an individual's age, gender, nutritional status, and genetic polymorphisms responsible for the biotransformation of inorganic arsenic [130] . chronic inhalation versus ingestion may result in irritation of the throat and respiratory tract [131] . individuals most affected by arsenic exposure are children, nursing children, and infants of exposed pregnant mothers [132] . acute inhalation of cadmium may lead to dyspnea and coughing [133] . long-term exposure to cadmium has been reported to contribute to emphysema, dyspnea, and inflammation of the nose, pharynx, and larynx [123] . individuals most affected by cadmium toxicity are those with occupations with cadmium exposure, such as those who work in certain types of factories, women, due to higher intestinal absorption because of low iron stores, and residents of asia due to high intake of rice grown in contaminated soil [134] . the 2013 us national health and nutrition examination survey (nhanes) demonstrated an association between obstructive lung disease and serum lead and cadmium concentrations in the blood, where cadmium was shown to partially mediate the association between smoking and obstructive lung disease [135] . in the 2015 korean nhanes, obstructive lung function was found to be associated with higher serum blood levels of cadmium and lead as well [136] . the specific mechanism of heavy metal burden and its effects on respiratory health must be further investigated. although testing and treatment of heavy metal burden have its limitations, it is worth considering as heavy metal accumulation can wreak havoc on the body. an example of heavy metal testing that can be used in practice is urine provocation testing with a chelating agent, such as fda-approved dmsa. eliminating heavy metals from the body can be potentially harmful and requires careful monitoring and guidance by an experienced healthcare professional. air pollutants that are used as indicators of air quality are carbon monoxide, lead, nitrogen dioxide, ozone, particles, and sulfur dioxide [137] . air pollution has been shown to have adverse effects on human health [138] . a 2017 systematic review and meta-analysis done in china showed an association between respiratory disease and ambient nitrogen dioxide, which is increased through fuel combustion, industrial production, and fuel exhaust [129] . diesel exhaust particles in particular have been associated with an increase in cytokines such as il-2, il-6, and ige in nasal mucosa [139] . nitrogen dioxide in particular can potentially contribute to respiratory disease as it is a free radical that is highly reactive and poorly water-soluble and can be deposited in the lungs when inhaled [138] . in another study performed in england, air concentration of nitrogen dioxide was significantly associated with respiratory hospital admissions [140] . other pollutants, such as fine particulate matter and ozone, have been shown to significantly affect respiratory function in copd patients [141] . increased ozone exposure has also been associated with increased airway inflammation and respiratory symptoms along with decreased respiratory function in children [142] . optimization of nutrition and antioxidant status is essential to combating the potential health effects of air pollutants. . [143] . it would be reasonable to assume having adequate stores and ability to utilize these nutrients may protect against other insults to the respiratory system as discussed in this section through their anti-inflammatory properties. acute and chronic exposure to certain chemicals can also pose a risk to respiratory health. obtaining a full occupational and social history when assessing individuals is important in order to identify any potential exposure to chemicals. one of the most well-known and common toxic chemical exposures that affects respiratory health is cigarette smoke. smoking cigarettes has been identified as a main cause of copd [144] . increased oxidative stress from inhaling cigarette smoke appears to activate the nf-kb inflammatory pathway, increasing the production of pro-inflammatory cytokines such as interleukin (il)-1, il-6, and il-8 and tumor necrosis factor-ɑ (tnf-ɑ) [144] . it also appears to reduce anti-inflammatory cytokines such as il-10 [145] . electronic cigarettes, or e-cigs, have been increasing in popularity in recent years and are marketed as a better alternative to tobacco cigarettes. however, recent evidence suggests that the vapor and associated chemicals produced by e-cigs may be harmful to the respiratory system, although further research is needed to determine the mechanism [146, 147] . exposure to metalworking fluid aerosols has been associated with asthma, hypersensitivity pneumonitis, impaired lung function, allergic alveolitis, and sinusitis [148] . a 2015 review also identified an association between occupational exposure to pesticides and increased risk of asthma and chronic bronchitis [149] . there are many chemicals that are toxic when inhaled. for example, inhalation of chlorine is toxic to the lungs, where low doses can cause airway injury and high doses can cause both airway and alveolar injury [150] . these injuries can manifest as dyspnea, hypoxemia, pulmonary edema, and pneumonitis [150] . high doses of carbon dioxide, such as that released from dry ice, can also induce respiratory failure. stress may also play a role in respiratory health and the body's ability to combat insults imposed on the respiratory system. from a physiological standpoint, it is worth noting that acute stress via activation of the sympathetic nervous system increases ventilation through the production of glucocorticoids [139] . repeated acute stress may also affect growth and repair mechanisms [139] . chronic biological stress in the form of infections can also be inflammatory and negatively affect the immune system and may affect an individual's susceptibility to respiratory complications. see the chronic infections and respiratory health section on page # below for further information on this association. however, appropriate amounts of physical stress, such as in the form of exercise, can be beneficial to respiratory health. some research has indicated a benefit of aerobic exercise to respiratory muscle strength in cystic fibrosis patients [151] . chronic stress can be defined as recurrent acute stress or inability to moderate acute stress responses [139] . this can be in the form of physical or emotional stress. chronic stress and negative emotions such as depression, anxiety, and anger may be linked to endocrine and immune processes [152] . immunoglobulin e (ige) and cytokine production, as well as respiratory inflammation, are markers that characterize the asthma response and have been shown to respond to stress in some capacity [139] . it has been hypothesized that increased stress may increase susceptibility to air pollution given its effects on the inflammatory response [139] . another connection between emotions and respiratory health is acknowledged in east asian medicine, noting the association between the lungs and feelings of sadness, grief, and anxiety [153] (. table 51 .3). asthma is a chronic inflammatory lung disease, triggered by either an ige allergic reaction or nonallergic factors, and results in reversible airway obstruction and inflammation of the airway [11] . it is characterized by recurrent episodes of wheezing, breathlessness, coughing, and chest tightness [11] . severe asthma or asthma that is chronic or poorly controlled may lead to airway and lung remodeling that involves deposition of fibrotic tissue which leads to constriction of the bronchi [18] . although the exact mechanisms have not yet been identified, compromised nutritional status, such as deficiencies in selenium, zinc, and vitamins a, c, d, and e, has been connected to asthma [155] . the pathophysiology of asthma, nutrition considerations, genotypic characteristics, and lifestyle influences will be discussed in this section. there are numerous potential triggers to the development and/or exacerbation of asthma which can be summarized in 7 box 51.2. the various causes of asthma have led to the classification of several different subtypes and endotypes of asthma in hopes of choosing more targeted treatments. the pathophysiology of asthma is complex and not fully understood, due in part to its heterogeneous nature, which necessitates its organization into individual phenotypes and endotypes. this organization is important to be able to utilize targeted treatments by identifying the root causes of the symptoms. however, more research is needed to more clearly identify the specific pathological mechanisms of each phenotype and particular treatment responses [156] . two of the most common asthma phenotypes are allergic and nonallergic asthma [147] ; allergic is characterized by increased th2 immunity (th2 high) and nonallergic defined by varying mechanisms depending on the trigger (th2 low) [157] (see also 7 chap. 19) . allergic asthma involves the ingestion of typically harmless environmental triggers (listed in . table 51 .3) by antigenpresenting cells in the bronchi, which interact with immature helper t cells that, in turn, trigger an unwarranted allergic response [18] . this reaction occurs from repeated exposure to a trigger and is referred to as the type 1 hypersensitivity response [18] . this increased th2 immunity upregulates eosinophilic inflammation, tissue damage, airway hyperresponsiveness, and bronchoconstriction [113] . mast cell activation disorders, which is characterized by diseases and conditions related to mast cell mediators and the activation of mast cells, must also be considered when addressing allergic asthma [158] . in contrast, nonallergic asthma can be caused by other factors such as anxiety, exercise, stress, dry air, cold air, viruses, hyperventilation, smoke, or other irritants [11] . . inhaled cadmium (cd) is deposited in the alveoli where it is then absorbed into the bloodstream cd is transported to erythrocytes or bound to albumin, where it is then taken up by the liver to form a complex with metallothionein (mt) cd interferes with the absorption of zinc and competes for the same enzyme binding sites enzymatic activity of zinc-dependent enzymes reduces preferential binding of cd to mt can cause zinc deficiency altered biotransformation and excretion of ingested arsenic via contaminated water are linked to respiratory complications chronic inhalation of arsenic may result in irritation of respiratory tract diesel exhaust particles in particular have been associated with increase in cytokines such as il-2, il-6, and ige in nasal mucosa [139] nitrogen dioxide is a free radical that is highly reactive and poorly water-soluble and can be deposited in the lungs when inhaled [102] rising pollen and mold counts [154] increasing ozone [154] chemicals increased oxidative stress from inhaling cigarette smoke may activate the nf-kb inflammatory pathway, increasing the production of pro-inflammatory cytokines such as interleukin (il)-1, il-6, il-8, tumor necrosis factor-ɑ(tnf-ɑ) cigarette smoke may reduce anti-inflammatory cytokines such as il-10 [145] stress repeated acute stress may also affect growth and repair mechanisms [139] ige and cytokine production, as well as respiratory inflammation, are markers that characterize the asthma response and have been shown to respond to stress in some capacity [139] increased stress may increase susceptibility to air pollution given its effects on the inflammatory response [139] ( individuals suffering from nonallergic asthma will tend to be less responsive to th2-targeted treatments due to a differing immune response at play [157] . some of the additional proposed phenotypes are eosinophilic, exacerbation-prone, exercise-induced, fixed obstruction/airflow limitation, poorly steroid-responsive, and adult-onset obesity-related [159] . several of the proposed endotypes are summarized in . the american partnership for eosinophilic disorders defines eosinophilic asthma as a type of asthma characterized by especially high levels of eosinophils, more commonly developed later in adulthood, although may occur in some children [160] . many with eosinophilic asthma do not have underlying allergies or history of allergic conditions such as eczema, food allergy, and hay fever, which are thought to be seen more in people with allergic asthma [160] . in contrast to allergic asthma, the cause of eosinophilic asthma is still unknown. histamine intolerance must also be considered in assessing the root cause of asthma. ingesting histamine-rich foods and beverages such as bananas, grapes, strawberries, citrus fruits, tomatoes, nuts, chocolate, pineapples, fish, spinach, fermented foods, and beverages [161] has been shown to provoke a histamine response that may result in asthma exacerbations, among many other potential signs and symptoms [162] . disruptions in redox, or oxidation/reduction, reactions in addition to hindered antioxidant defense have been . usually not responsive to glucocorticoids [159] based on data from ref. [157] found to be a risk factor for asthma severity and development [163] . the levels of glutathione, one of the lung's most predominant antioxidants in both reduced and unreduced forms, are thought to be important for lung homeostasis and tied to asthma [163] . more research is needed to determine the exact differences in the pathophysiologies of the various subtypes of asthma in order to develop more targeted treatments. minerals such as zinc, selenium, copper, and manganese may serve as cofactors to major enzymes with antioxidant activity in the lung, such as superoxide dismutase, catalase, and glutathione peroxidase [164] . asthma has been associated with decreased activity of these enzymes [165] . low selenium intake has been associated with multiple chronic diseases including asthma [163] . selenium serves as a cofactor to glutathione peroxidase, an enzyme with antioxidant activity in the lung that is responsible for maintaining gsh/gssg redox balance [163] . imbalance between oxidants and antioxidants seems to serve an important role in asthma. levels of nonenzymatic antioxidants glutathione, ascorbic acid, alpha-tocopherol, lycopene, and beta-carotene, in addition to antioxidant enzymes superoxide dismutase (sod) and glutathione peroxidase, were significantly lower in asthmatic children compared to healthy controls [165] . the amino acids glycine and glutamine, which are important in glutathione synthesis, were also found to be significantly lower in children with asthma [165] . dha has also been found to be abundant in airway mucosa, where it is decreased in individuals with asthma and cystic fibrosis [166] . magnesium is known to elicit the relaxation of bronchial smooth muscle, decrease responsiveness to histamine, have an anti-inflammatory effect, and decrease the susceptibility of animals to developing anaphylactic reactions [25] . it is estimated that two-thirds of the population in the western world is not consuming the recommended daily allowance of magnesium [167] . magnesium can be used intravenously as an effective treatment of acute asthma attacks. one double-blind controlled trial that used 1.2 g of magnesium sulfate when patients did not respond to treatment with beta-agonists found decreased likelihood of hospitalization and improved lung function [168] . magnesium sulfate as an adjunct therapy with bronchodilators and steroids has also been shown to have a benefit in children with moderate to severe asthma [168] . although the exact mechanism is not yet known, magnesium is thought to increase glutathione concentrations in the lung [169] . more research is needed to determine additional associations between specific nutrients and asthma. however, optimization of the nutrients discussed in this section has the potential to reduce the severity and/or progression of asthma (. fig. 51.5) . asthma has a strong genetic component, with more than 100 genes associated with it in varying degrees across many populations [18] . more recent potential genetic associations include filaggrin, which encodes for the epithelial barrier; ormdl3, which encodes transmembrane protein; beta-2 adrenergic receptor gene, expressed throughout smooth muscle and epithelial cells of the lung; and interleukin-4 receptor gene, which has a variant associated with elevated ige [171] . a 2011 systematic review and meta-analysis showed that deficiencies in selenium, zinc, vitamins a, c, d, and e, and low fruit and vegetable intake could be associated with the development of asthma [155] . although this data is tenuous due to lack of randomized controlled trials, it does give some indication of the relationship between nutrition status and dietary patterns with respect to asthma development. more research needs to be done to isolate the impact of these nutrients and dietary patterns on asthma prevention and development. a 2015 review conducted by berthon and wood noted the protective effects of the mediterranean diet for allergic respiratory diseases as evidenced by epidemiological studies. this diet emphasizes minimally processed plant foods in the form of fruit, vegetables, cereals, beans, breads, nuts, seeds, and olive oil and low to moderate intake of dairy, poultry, fish, and wine, as well as low intake of red meat [172] . this association was the strongest in children, where the mediterranean diet had a protective effect on atopy, wheezing, and asthma symptoms [172] . however, there is less data available to support this pattern in adults. the same review noted an association between the "western" diet, which emphasizes refined grains, red and cured meats, french fries, sweets and desserts, and highfat dairy products and increased risk of asthma in children [172] . a meta-analysis and systematic review done in 2014 showed a reduction of risk in childhood wheezing with high fruit and vegetable intake and also showed negative association between fruit and vegetable intake and asthma risk in adults and children [173] . in contrast, food allergy has been especially linked with allergic asthma in children [161] . a study examining food allergy in asthmatic children identified higher serum levels of ige in asthmatic children compared to healthy controls, where all asthmatic children in the study were also identified as having a positive skin prick test (spt) to various food allergens [174] . a study done on 322 children under the age of 1 diagnosed with asthma, with or without allergic rhinitis, was placed on a meat-based formula of carrots, beef, broccoli, and apricots for 6 weeks. it was found that 61% had nearly complete resolution of symptoms [25] . this same study also found that the most common food triggers were milk, egg, chocolate, soy, legumes, and grains [25] . while food allergy as a cause of asthma is more common in children, hidden food allergy has been reported to be the root cause of asthma in around 40% of adults [25] . improvement in respiratory symptoms was also seen in a small study of adults given an antigen-free elemental diet in a hospital setting [25] . removal of food triggers has also been linked to improvement in exercise-induced asthma [25] . identifying food allergies can be a complicated process because many of the testing methodologies such as skin prick tests (spts) and blood tests can yield false-positive results for up to 50-60% of cases, according to the food allergy research & education organization [175] . a food elimination diet and/or oral food challenge can be a powerful tool in determining food allergy specific to asthma symptoms, where a dietitian or nutritionist in conjunction with physician and/or allergist can serve an important role through this process to support the individual. oxidative stress may play a key role in the development of asthma, which can also be true for the development of chronic diseases such as cardiovascular disease, diabetes, and cancer [117] . it has been shown that obesity may be a risk factor for people with and without allergy and may worsen pre-existing asthma [159] . individuals with asthma are twice as likely to have gastroesophageal reflux disease (gerd) than people who do not have asthma, especially those resistant to treatment [159] . celiac disease and asthma have also been linked. an italian cohort study was done that showed a significant association between treated asthma and celiac disease, where antibiotic exposure in the first year of life was controlled for and not found to contribute to this association [176] . it has also been found that individuals with celiac disease following a glutenfree diet experienced improvement in asthma symptoms [25] . it is well-known that toxic exposure to particulate matter, airborne pollutants, or cigarette smoke can trigger asthma symptoms [165] . more specifically, a dose-dependent relationship between cigarette smoke exposure and rates of asthma has been shown [165] . traffic density and asthma exacerbations have also been clearly demonstrated [165] . certain medications may also serve as triggers to asthma. aspirin-exacerbated respiratory disease (aerd) is considered another asthma subtype caused by nonsteroidal anti-inflammatory drugs (nsaids) and is characterized by asthma, chronic rhinosinusitis, and acute respiratory reactions [159] . in addition, overuse of antibiotics in childhood has been linked to asthma [18] , indicating a connection between the microbiome and asthma development. allergic bronchopulmonary mycosis (abpm) noted in . table 51 .4 is caused by a hypersensitivity reaction to fungal colonization of the airways [159] . this is typically caused by the fungus aspergillus fumigatus. without treatment, this may lead to fixed airflow obstruction and bronchiectasis [159] . the progression of asthma is complex and multifaceted, from preconception through childhood and adulthood. research suggests that early life events are largely predictive for regulatory mechanisms within the pulmonary immune system [177] . for example, prenatal exposure to a farming environment, one rich in microbial compounds, is thought to influence innate immune patterning in the mother which may affect the development of the neonatal immune system [177] . this influence in immune patterning can be seen through higher expression of toll-like receptors 2 and 4 and cd14 on peripheral blood cells, which implies possible desensitization to allergens in children [178] . t regulatory cells, which serve an important role in immune regulation and are thought to play an important role in asthma by suppressing the th2 inflammatory response to harmless air particles, have been shown to be impaired in the cord blood of neonates at hereditary risk for allergy [179] . in the 2017 study performed by singh et al. looking at serum ige and cutaneous sensitivity to food allergens in asthmatic children here was a negative correlation of total ige and duration of breastfeeding, indicating a connection between breastfeeding and the immune response [174] . additionally, reduced maternal intake of vitamins d and e and zinc during pregnancy has been associated with increased asthma symptoms in children [180, 181] . vitamin d has been associated with the maintenance and/or development of the t regulatory cells stated earlier in mice; however more research is needed to determine a definitive association in humans [177] . a clinical trial performed on non-smoking asthmatic patients showed higher vitamin d levels were associated with greater lung function; furthermore, supplementation with vitamin d showed improved treatment response to glucocorticoids [182] . vitamin d may also directly increase the antiinflammatory cytokine, interleukin (il)-10 and also enhance steroid-induced il-10 production (see . fig. 51.6) [177] . more research is needed to determine the exact mechanism of vitamin d in asthma and respiratory disease. beta-agonists, combined with corticosteroids, serve as the primary conventional therapy [183] . typically, a short-acting beta-agonist will first be prescribed to manage symptoms as needed, where low-dose inhaled corticosteroids may also be prescribed [156] . if symptoms persist, it is recommended to evaluate problems such as adherence to use, inhaler technique, or persistent allergen exposure and comorbidities [156] . once these are ruled out, the step-up treatment is a combination of an inhaled corticosteroid with a long-acting beta-agonist [156] . a summary of other conventional treatments and their mechanisms can be found in . table 51 .5 below. unfortunately, conventional methods for the treatment of asthma may have harmful side effects. for example, the use of . fig. 51.6 effect of asthma treatments on regulatory pathways. (reprinted from lloyd and hawrylowicz [177] . with permission from elsevier) systemic glucocorticoids may lead to immunosuppression, cataracts, and osteoporosis, where long-acting beta-agonists have the potential of increasing asthma exacerbation risk and death [25] . beta-agonist desensitization is thought to be one of the reasons for increasing asthma exacerbation risk and death [184] . related to several subtypes of asthma and their differing pathophysiologies, it is important to first determine the subtype before deciding on treatment. for example, in an individual with allergic asthma, this could be a potentially simple fix once the allergen that exacerbates symptoms is identified. a more conventional approach may involve starting the individual on an inhaled corticosteroid or an ige antagonist (i.e., omalizumab) [159] , rather than identifying the root cause of the patient's symptoms. while medications may be warranted until the trigger is identified, finding the underlying causes may not be common practice in many conventional settings. in contrast, the ifmnt assessment takes a much deeper dive into identifying triggers and any nutrient insufficiencies, inflammation or immune dysregulation, biochemical individuality, lifestyle, energy dysfunction, toxic load, sleep, and stress issues are taken into account. with this information, the practitioner can make more targeted dietary, lifestyle, and supplement recommendations to obtain sustained resolution of symptoms by treating the root cause (. table 51 a 26-year-old female presented with a complaint of reactive airway disease, which was diagnosed as asthma and had been prescribed inhalers. she reported that she felt like she had difficulty breathing most of her life, especially when exercising. however, her condition was not severe enough to seek help until she was 25 years of age. she reported a lot of stress during this time related to applying for a postgraduate training position. she also reported 1 year prior to diagnosis developing new allergic symptoms. her past medical history was significant for conditions related to airways, including chronic sinus infections, strep throat, bronchitis, and recurrent pneumonia. she could not remember the last time she felt well but assumed it was sometime as a young child. her nutrition and health goals were to breathe better and to not have to rely on inhalers. the following data was collected on her initial visit. . methyl xanthine found in tea used less commonly due to side effects relaxes airways due to inhibition of phosphodiesterases; acts as a functional antagonist in airway smooth muscle [171] based on data from ref. [18] . table 51 .6 summary of an integrative and functional medical nutrition therapy assessment adequacy of nutrient-dense foods to begin to assess nutritional status organic or nonorganic to assess toxic load and nutrient intake food preparation and processing to assess nutrient content and identify potential contaminants (e.g., plastic endocrine disruptors) assess food sensitivities or intolerances to identify potential triggers microbiome status: assess comprehensive digestive stool analysis for microbiology and fermented food intake; history of antibiotics or microbiota agonists (medications, toxins, stress, etc.) toxin intake via plastics or inhalation and skin absorption which may affect immune response assess flavonoids intake as they are antioxidant and anti-inflammatory compounds with mast cell inhibitory action; adequacy may reduce airway reactivity consider celiac disease and gluten intake as potential inflammatory antigens mineral assess and restore zinc, selenium, magnesium, manganese, iron, and iodine status to normal reference. caution to not supplement or intake of food sources higher than reference antioxidants assess and restore antioxidant balance; vitamins a, c, d, and e and glutathione assess quercetin intake (leafy vegetables, broccoli, red onions, peppers, apples, grapes, black and green tea, red wine) as it may act as mast-cell stabilizing agent inhibiting release of histamine, tnf-alpha release, formation of prostaglandin d2, reducing interleukin production consider supplementation of quercetin if quercetin intake is low [185] protein status assess and restore to support connective tissue and immune status ensure adequate glutamine and glycine intake oils/lipid/fatty acids assess fatty acid balance as dha important in lung tissue integrity assess adequate serum cholesterol and fat intake to support lipid bilayer important for cellular function in lung (epithelial cells, surfactant production, etc.) methylation assess methylation status and detoxification capacity of toxins related to asthma exacerbation; important assessment biomarkers suggested: mcv/mch, homocysteine, methylmalonic acid, rbc folate, genomic methylation snps inflammation/immune dysregulation assess asthma biomarkers to help identify root cause (see . fig. 51 extreme exhaustion, depression, add, anxiety (accompanied by panic attacks), constipation, pain in legs, neuropathy in feet (numbness and tingling), rapid heartbeat, and a very severe rash on feet known as chilblains. 5 utis -recurrent as a child. 5 poor immune function (frequent infections). 5 antibiotic use (very frequent from childhood into adulthood). 5 sinus infections, strep throat, and bronchitis -she had recurrent sinus infections and strep throat about once a year every year and often this would lead to bronchitis, she could not remember if she had these issues before middle school. 5 depression, anxiety, add. 5 acne. 5 peptic ulcers. 5 yeast infections -multiple throughout college. 5 eczema. 5 two recent episodes of pneumonia the last episode resulted in her asthma diagnosis. 5 asthma. evaluate exposure to fungus to identify allergic bronchopulmonary mycosis assess individual's medication history, considering short-and long-term use of conventional treatments evaluate exposure to particulate matter, airborne pollutants, cigarette smoke, or toxic metals such as cadmium and arsenic sleep and stress assess sleep adequacy (7-9 hours with 5-hour rem sleep) and quality (good sleep hygiene with little light/ sound/emf disturbance) to support detoxification of toxins that may worsen respiratory status and aid in repair of damaged lung tissue . periostin plays a role in the pathogenesis of allergic diseases, including asthma, as it is associated as a downstream molecule of the cytokine, il-13. periostin is used as a biomarker for type 2 immunity and can be used to determine the potential effectiveness of medications used to treat asthma, such as anti-ige antibodies and anti-il-13 antibodies. asthmatic patients with high serum periostin tend to be aspirin intolerant, eosinophilic, late asthma onset, and have a high nitric oxide fraction. high periostin can also indicate a reduced response to inhaled corticosteroids [186, 224] . periostin in the right panel is stained brown and is localized in the thickened basement membrane in asthmatic patients. (reprinted from izuhara et al. [186] . with permission from the korean academy of asthma, allergy and clinical immunology) for several weeks, led to being immobile for almost 2 weeks 5 8th-12th grade: was often sick (strep, sinus infections, bronchitis); described it as being constantly sick from fall through winter every year; also developed eating disorder during this time; had severe menstrual cramps (induced vomiting) accompanied by acne, which led to being put on birth control at age 17 as a precursor to accutane (never prescribed); chronic constipation starting during this time university 5 freshman -sophomore year: eating disorder was most severe during this time. 5 first semester of freshman year: developed digestion issues, after eating certain foods (especially mexican or salsas), stomach would become distended, experienced pain, and often would result in vomiting. pain so severe during finals week she was admitted to er with no diagnosis. ct scan revealed possible peptic ulcers. 5 junior-senior year: depression, anxiety, and inability to focus were most severe during this time which resulted in missing a lot of class and struggling as a student; suffered multiple panic attacks; gained a lot of weight (from 120 to 180 lb); end of senior year became engaged to be married -moved to dallas, tx. 5 lived in dallas for 6 months, continued to experience depression and anxiety and weight gain, and moved back to home state 5 initially started running (~2 miles a day) and experiencing inability to breathe, diagnosed with pneumonia, prescribed inhaler to help with running; other symptoms: eczema around the eyes and neck (after running outside), pain in calves, numbness and poor circulation in feet (pulse not detected by several health professionals), and development of chilblain rash (very painful, itching, lasts about 3-4 weeks from development to resolution); increased running -ran a half-marathon. visited pcp and several specialists for help with chilblain rash with no resolution or diagnosis; lost a lot of weight (from 170 to 140 lb). 5 ongoing increased depression, anxiety, and inability to focus; pcp rx cymbalta (depression and anxiety); cymbalta discontinued after ~2 months (did not tolerate side effects), continued psychological therapy for several months; chilblain rash continued. stopped running long distances. gained weight back (from 140 to 170 lb); subsequently saw blog for integrative rd and followed suggestion to eliminate gluten and focusing on whole foods diet. 5 chilblains and eczema began to resolve while following integrative rd recommendations of gluten-free diet with some improvements. however, difficulty breathing got worse, and diagnosis of asthma was made with fast-acting inhaler used for exercise; as time progressed, breathing continued to worsen, led to daily inhaler use. weight at this time is still at around 170 lb. high dairy diet (consumed dairy products at most meals and snacks), consumed three smaller meals with three snacks in between 5 meals and snacks balanced with protein, fat, and carbs, with carbs coming from fruits and vegetables and fat mainly from full fat cheese, greek yogurt, and butter 5 mostly nonorganic produce and commercially raised meats digestion, assimilation, and elimination 5 hx of peptic ulcers and chronic constipation (bm ~1-2 times a month) 5 bms currently at about 2 × per week on encounter utilization, cellular, and molecular (mapdom) 5 hx of likely gluten sensitivity. 5 presented symptoms of possible dairy sensitivity (bloating, acne, asthma). 5 evidence for compromised intestinal barrier. 5 minerals: infrequent bms could indicate low fiber or low mineral status (mg); when bms do occur, they are hard and dry (low mg); severe menstrual cramps (low mg); labs showed low k and na, on yaz birth control (low zinc and low b vitamins). 5 antioxidants: consumed adequate fruits and vegetables each day. 5 protein: has some evidence of poor/slowed wound healing as evidenced by sore on leg that has not completely healed after a year; cuts that take months to heal. 5 d and fat-soluble a, e, and k vitamins -hx of poor immune function (low d), vdr +/+ (low d and possibly a). 5 oils/fatty acids: high omega-6/omega-3 ratio, higher intake of damaged fats, very low intake of omega-3. 5 methylation: symptoms of depression, anxiety, add combined with mthfr c677t snp and on yaz (low b6 and folate). 5 eicosanoid fatty acids status -suspect issues with pge1 series pathway to control inflammation due to following signs and symptoms: allergies, autoimmune condition (asthma), peptic ulcers, eczema, and severe menstrual cramps 5 immune function -suspect gut dysbiosis due to following s&s: poor immune function, yeast infections, hx frequent antibiotic use, cyst, and constipation body composition 5 genetic makeup that indicated prone to gluten and dairy sensitivity, low vitamin d status, and impairment in methylation 5 broad spectrum probiotic + fermented foods 5 bioactive b complex (includes 50 mg p5p b6 and 800 mcg 5 thf) 5 260 mg gla evening primrose oil and zinc 3. aim to eat three larger meals a day, allowing space in between of ~ 5 hours; increase omega-3 intake by adding in small fatty fish, such as sardines or anchovies, once per week and taking fish oil; decrease omega-6 intake, switch from conventionally raised meats to organic, pasture-raised; and replace fat in diet from dairy with coconut sources, more nuts, and avocados. 5 patient presented ~6 months after the initial visit (september 2015). her breathing had improved immensely. she was able to stop taking her albuterol inhaler before exercise, recently stopped daily inhaler. 5 after dairy-free diet for 3 months, reintroduced dairy (cheese, butter, yogurt). asthmatic symptoms returned about 2-3 days after the addition of each. noticed the more dairy consumed, the worse her symptoms became. 5 at time of appointment, diet whole foods, gluten-free, and dairy-free. weight loss 10 lb within the first month of going dairy-free, continued to lose some weight. when reintroduced dairy symptoms of bloating and increase in weight, which resolved returning to dairyfree diet. 5 bms are regular now at ~ 2 × daily. this patient case followed some common patterns in the development of chronic disease and the comorbidities that are common, especially autoimmune conditions like asthma. the first is the genetic susceptibility of the individual; several snps are prone to dairy sensitivity. second, significant evidence for gut dysbiosis, promoted compromised gut barrier, can contribute to the development of dairy sensitivity. third is the exposure to dairy protein antigen. diet history evidenced trigger for asthmatic condition. additionally, inflammation, immune dysfunction, and methylation issues present. signs and symptoms significant for decrease in pge1 series anti-inflammatory pathways. low dietary omega-3s potential contributor to asthma. immune dysfunction evidenced by extensive history of infection-antibiotic use. genomic snp mthfr c667t gene, which indicated a greater need for folate. the use of yaz birth control and symptoms of depression, anxiety, and add known further to deplete b6 and folate. the diet and supplements recommended targeted control of inflammation, restore gut ecology, promote proper methylation, and replete nutrient insufficiencies. results from 6-month follow-up showed successful outcome in helping improve breathing and wean her off of inhalers. this case is an example of the ifmnt approach able to address the complexity of the whole patient story and bring the metabolic priorities into a manageable intervention program for the individual. one study found that the composition of the nasopharyngeal microbiota in children was linked to the frequency of upper respiratory tract infections and acute sinusitis [189] . a study that intranasally inoculated mice with lactobacillus fermentum reduced the amount of s. pneumoniae in the respiratory tract and increased the number of macrophages in the lung and lymphocytes in the trachea [189] . these findings may indicate a benefit of manipulating the upper respiratory tract microbiota with orally or nasally administered probiotics in the prevention and/or treatment of upper respiratory tract infections. allergic bronchopulmonary mycosis (abpm) is caused by a hypersensitivity reaction to fungal colonization of the airways. this is typically caused by the fungus aspergillus fumigatus. without treatment this may lead to fixed airflow obstruction and bronchiectasis [159] . guillain-barre syndrome (gbs) is a rare neurological disorder in which the body's immune system attacks the peripheral nervous system, known as the network of nerves located outside of the brain and spinal cord [190] . it is often preceded by a bacterial or viral infection. there are several potential mechanisms in which these infections trigger gbs. if an individual contracts a campylobacter jejuni bacterial infection, antibodies made to fight this infection can attack axons in motor nerves, which can potentially cause paralysis and respiratory failure [190] . campylobacter can be ingested via contaminated food or other exposures [190] . pérez-guzmán 2005 states that hypocholesterolemia is common among tuberculosis patients and suggests that cholesterol should be used as a complementary measure in antitubercular treatment [8] . alpha-1 antitrypsin (a1at) deficiency is an underrecognized disease in the united states, with around documented 100,000 people suffering from it, according to the alpha-1 foundation. this deficiency is inherited through autosomal codominant transmission, meaning affected individuals have inherited an abnormal aat gene from each parent [191] . individuals with this deficient allele present with aat levels at less than 35% to low-end normal levels [191] . however, it is also possible for individuals with a variant of this allele to be asymptomatic given different environmental conditions or lifestyle factors, such as refraining from smoking to reduce lung disease development risk [191] (7 box 51.4). a1at deficiency most often manifests in the lungs as chronic obstructive pulmonary disease (copd) (i.e., emphysema or bronchiectasis or "genetic copd"). a1at deficiency is often undiagnosed because people with genetic copd experience the same symptoms as people with copd, such as [191] : 5 shortness of breath 5 wheezing the only way you will know for sure if you have genetic copd due to alpha-1 is to get tested. ________ a1at deficiency can manifest in the liver as cirrhosis. symptoms related to the liver 5 unexplained liver disease or elevated liver enzymes 5 eyes and skin turning yellow (jaundice) 5 swelling of the abdomen (ascites) or legs 5 vomiting blood (from enlarged veins in the esophagus or stomach) a1at expresses sometimes in the skin as panniculitis [191] . panniculitis typically appears as raised red spots on the skin, which may break down and give off an oily discharge. while panniculitis spots (called nodules) may appear anywhere on the body, the most common places are the thighs, buttocks, and areas subject to injury or pressure. normal genotype m m 5 most common abnormal genes are called s and z 5 abnormal variant combinations: 5 zz (highest risk) 5 sz (lower risk increasing if smoker, inhalant pollutants) 5 mz (lower risk of carrying an a1at gene variant; considered "carriers") 5 alpha-1 is the most commonly known genetic risk factor for emphysema 5 up to 3% of all people diagnosed with copd may have undetected alpha-1 5 alpha-1 can also lead to liver disease. the most serious liver diseases are cirrhosis and liver cancer 5 the world health organization (who), american thoracic society (ats), and the european respiratory society (ers) recommend that everyone with copd be tested for alpha-1 alpha-1 is a progressive disease that benefits from early detection. it can cause serious lung diseases, such as copd and emphysema when undiagnosed. in some cases, alpha-1 can also cause liver disease [225] symptoms related to the lung [225] : 5 shortness of breath 5 wheezing 5 chronic bronchitis, which is cough and sputum (phlegm) production that lasts for a long time 5 recurring chest colds 5 less exercise tolerance 5 year-round allergies 5 bronchiectasis the alpha-1 antitrypsin (a1at) protein protects the body, especially fragile lung tissues, from the damaging effects of a powerful enzyme called neutrophil elastase that is released from white blood cells. in a1at deficiency, a genetic mutation reduces levels of the protective protein in the bloodstream. a1at deficiency can lead to chronic obstructive pulmonary disease (copd), specifically emphysema, and liver disease. smoking, which can inhibit what little a1at protein an affected person does have, increases the risk of lung disease. alpha-1 antitrypsin deficiency is completely determined by mutations in a single gene. the severity of symptoms is mostly a function of which mutations a person has and how many copies. however, smoking can greatly increase the risk of lung disease due to aat mutations. 23andme reports data only for the pi * m, pi * s, and pi * z versions of the gene that encodes aat. keep in mind that it is possible to have another mutation that causes this condition that is not included in this report [192] . a1at deficiency is a genetic disorder that reduces circulating levels of a protein that protects the lungs by trapping a1at in the liver, where the protein is produced, and prevents a1at from entering circulation. a1at deficiency can lead to chronic obstructive pulmonary disease (copd), specifically emphysema, and liver disease. when a disease-causing mutation is fairly common, as the pi * s and pi * z mutations are in europeans, it suggests that the mutation actually conferred an evolutionary advantage at one time. some researchers have suggested that several thousand years ago when the pi * z and pi * s mutations first arose, these versions of the gene for a1at gave people a survival advantage by creating an environment in their lungs that helped fight off infections. the scientists theorize that the antimicrobial benefits of the aat mutations outweighed the cost of an increased risk of copd and liver disease in the era before antibiotics were available [193] . in contrast to lung disease, manifestation of liver disease related to a1at can be referred to as a "toxic gain of function, " due to accumulation of mutant a1at protein rather than protease deficiency within the liver [144] . when taken together, fibrotic lung diseases are the leading cause of mortality worldwide. under the umbrella of interstitial lung disease (ild), pulmonary fibrosis (pf) is the most common. any ild that involves scarring of the lungs falls in the pulmonary fibrosis category. pulmonary fibrosis is the scarring of lungs, which destroys tissue over time, making it impossible to transfer oxygen from inhaled air into the bloodstream. there are more than 200 different diseases under the pulmonary fibrosis umbrella. because pf is often misdiagnosed or goes undiagnosed, there is not an accurate count of those with these diseases. however, it is estimated that as many as 1 in 200 adults over 60, or 200,000 people in the united states, are affected [184] . there are more than 50,000 deaths from ipf every year in the united states. more people die each year from idiopathic pulmonary fibrosis than from breast cancer [194] . there are other forms of interstitial lung disease including the newly identified pleuroparenchymal fibroelastosis, cryptogenic organizing pneumonia (cop), desquamative interstitial pneumonitis, nonspecific interstitial pneumonitis, hypersensitivity pneumonitis, acute interstitial pneumonitis, interstitial pneumonia, sarcoidosis, and asbestosis [195] . symptoms include cough and dyspnea, restrictive pulmonary function tests with impaired gas exchange, and progressive lung scarring. the disease progresses with an initiation of inflammation. fibrosing starts with the action of transforming growth factor-β (tgf-β)-dependent differentiation of fibroblasts to myofibroblasts, which then express α-sma (smooth muscle actin) [196] . after the tgf-β-dependent differentiation of fibroblasts to myofibroblasts, which express α-sma, there is sustained, excessive deposition of collagen by the myofibroblasts in the lung interstitium leading to the progressive lung damage in patients with pf [185] . research published in 2011 supported the idea that dysfunctional type ii aecs (alveolar epithelial cells) facilitate lung fibrosis through increased susceptibility to injury, leading to excessive and dysregulated remodeling [197] . the disease seems to progress in steps, and inflammation is not typically present continuously, except during certain periodic episodes of deterioration (. fig. 51.8 ). there are five main categories of pf causes: drug-induced, radiation-induced, environmental, autoimmune, and occupational. of these five, four have identifiable causes. some of the autoimmune diseases that can lead to pf are rheumatoid arthritis, scleroderma, sjogren's syndrome, polymyositis, dermatomyositis, and antisynthetase syndrome. idiopathic pulmonary fibrosis (ilp) is defined as pf with an unknown cause, including a genetic cause for some families [see . fig. 51.9 ]. the symptoms of ilp are a dry, hacking cough, shortness of breath, fatigue, chest discomfort, loss of appetite, and unexplained weight loss, all caused by the fibrosing of the lungs. diagnosis can be difficult, and pf is often misdiagnosed as copd or other more common lung diseases. in addition, in the recent past, path to a true diagnosis was invasive. since damage to the lungs, even through a diagnostic biopsy, can trigger further lung damage or a period of fibrosis, many physicians or patients are cautious with a biopsy approach to diagnosis. since the current treatments are limited, one must evaluate whether defining the exact form of pf is necessary for treatment and follow-up. difficulty breathing, crackling sounds while breathing, and low oxygen levels are the first indicators. clubbed fingernails may also be a symptom. high-resolution ct scans are performed, which can show scarring. the pulmonologist will ask many questions and order more blood tests to try to distinguish between the 200 forms of pf. the future is pointing to molecular endotyping as a more accurate way to diagnose. molecular endotyping includes genetic, metabolic, transcriptional, and environmental factors to help determine the pathophysiology [199] . genetic research has been progressing for a couple decades with illuminating results. there are more than a dozen genetic variants that have been associated with this family of diseases. researchers now believe at least 20% of idiopathic pulmonary fibrosis (ipf) patients with multiple family members suffering from ipf have some common familial genetic variants, which may allow researchers to eventually drop the term idiopathic and further define various forms or categories, with differing progression or outcome. the name given to this version of interstitial pneumonias is familial interstitial pneumonia (fip) [200] [see . currently two categories of genetic focus have been defined: those genes related to telomere biology (shorter telomeres) and those related to surfactant protein processing. the genes related to shorter telomeres are tert, terc, htr, dkc1, and rtel1. more mutations have been found in the tert gene, which encodes the protein component of telomerase, than any other gene. further research may allow targeted therapies to affect the genetic expression associated with the development of ipf [201, 202] . a common variant within the promoter of the muc5b gene is the most replicated single-nucleotide polymorphism related to familial and sporadic forms of ipf as well as early radiographic findings of ipf [203] (. figs. 51.9 and 51.10). wound contraction and re-epithelialization . fig. 51.8 the cellular and molecular mechanisms of fibrosis in multiple organs. the cellular and molecular mechanisms of fibrosis in multiple organs. once an injury occurs in an organ, epithelial and/or endothelial cells are impaired, which results in the release of chemokines and growth factors, including il-13 and tgf-b1. macrophages and monocytes are recruited and activated, both of which further release cytokines and chemokines and further induce fibroblast activation. activated fibroblasts transform into a-sma-expressing myofibroblasts and migrate into the wound along the fibrin lattice. ecm is excessively accumulated, and some parenchymal cells (hepatic stellate cells in the liver, tubular epithelial cells in the kidney, alveolar epithelial cells in the lung, or cardiomyocytes in the heart) are further differentiated into myofibroblasts or fibroblasts by the stimulation of cytokines and chemokines, especially for tgf-b1. after the inflammatory phase, two events occur. one is the regeneration of injured tissues followed by wound contraction and reepithelialization. in contrast, once chronic injury, inflammation, and necrosis occur, myofibroblasts are perpetually activated, and excessive ecm is deposited, finally resulting in fibrosis formation. ctgf, connective tissue growth factor; ecm, extracellular matrix; egf, epidermal growth factor; emt, epithelial-mesenchymal transition; hsc, hepatic stellate cell; il, interleukin; mmp, matrix metalloproteinase; tgf, transforming growth factor; timp, tissue inhibitors of metalloproteinase. (reprinted from chen et al. [198] . with permission from elsevier) conventional treatment is typically palliative. the american thoracic society recognizes that supplemental oxygen and transplantation are the only suggested treatments for ipf. supplemental oxygen is prescribed, and the need for oxygen increases over the progression of the disease. keeping the oxygen saturation level over 90% (normal is in the upper 90s) is ideal and is how healthcare providers determine the level of supplemental oxygen to be used. cardiovascular exercise, in this case called pulmonary rehabilitation, is recommended to maintain as much use of the lungs as possible. infrequently, nutrition and counseling are recommended and are placed into the category of symptom management. nutrition can have a significant role in the management of this disease, but little implementation exists in some of the proposed protocols. there are currently two medications available in the united states with minor impact on the disease progression: nintedanib (commonly called ofev) and pirfenidone (esbriet). histopathological quantification showed similar amounts of dense collagen fibrosis, fibroblast foci, and alveolar macrophages in untreated or pirfenidone-or nintedanibtreated ipf patients [204] . both have significant side effects, including fatigue and gi issues, and patients may have to evaluate their quality of life versus length of life. other antiinflammatories or immune-suppressing medications used are corticosteroids, mycophenolate mofetil/mycophenolic acid (cellcept®), or azathioprine (imuran®). immunesuppressing drugs may be harmful for those with short telomeres, and researchers are exploring this potentially contradictory recommendation [205] . lung transplantation is a final effort. about is half of all transplants. with the prevalence of this disease closer to 200,000, this is a small fraction of those with the disease. some of those with the transplant go on to live productive lives, while others develop pf again, in the transplanted lungs. overall, there is a shorter life expectancy in those with pf, because of telomere shortening. bone marrow or immune response abnormalities have been found in some ipf cases before and after lung transplantation, which increases the associated morbidity. as stated above, inflammation occurs at the beginning and throughout the progression of all fibrosing diseases, including those of the lungs. therefore, reducing inflammation is one wise strategy to slow fibrosing. there are several nutrients that can help slow or reverse the inflammation involved in the fibrosing process. the following two-part diagram shows where in the fibrosing pathogenesis each phytonutrient acts [198] (. fig. 51 .11). a few of those compounds are discussed in more detail here. curcumin, the active constituent in the common spice turmeric, has been shown to reduce fibrotic activity in several studies. in mice, curcumin inhibited collagen secretion of ipf fibroblasts. it affects the signaling of tgf-β, in a dosespecific manner, resulting in reduced expression of α-sma, which is responsible for inappropriate fibrosing. this was shown in vitro and in vivo in mice, with intraperitoneal, but not oral, administration. at the time of the study, oral ingestion of curcumin was not adequately absorbed into plasma, and there was greater than ten times plasma concentration of curcumin following an intraperitoneal injection [88] . however, some new oral products on the market are showing greater absorption. the results of this study suggest more research into curcumin, including improved delivery into patients. for example, some delivery options may include nebulized curcumin directly into the lungs, binding it to highly absorbable agents for oral use or liposome-encapsulated curcumin suitable for intravenous use (already shown to be effective in an animal model). according to manufacturers of curcumin products, some are more readily absorbed than others. one study on fibrosing suggested that a dose of around 2200 mg curcumin split into three doses taken with meals including pepper (bioperine) achieved doses that were sufficient to exert the desired therapeutic effect. research into using quercetin also has some promising results in slowing the progression of ipf. quercetin reversed lung fibrosing in mice and reversed the disease progression normally caused by typical pulmonary senescence markers [206] . it is worth mentioning that n-acetylcysteine (nac), a long-used therapeutic agent for breaking down mucus in the lungs, has not been found to be effective in those with ipf. in fact, due to its acidic nature, it has even been shown to be harmful when used in the inhaled form [207] . several of the drugs being developed have a natural product as a model or foundation. until a drug or gene therapy is developed that stops or reverses this disease, it may make sense for the patient to focus on anti-inflammation and reducing myofibroblast activation, the extracellular matrix (ecm) accumulation, and the epithelial-mesenchymal transition (emt) process. the phytochemicals listed in . fig. 51 .11 would be good ones to investigate. with the recent identification of genes associated with ild, a call for gene-related therapies both related to telomere lengthening and connective tissue disease has been initiated, and this type of therapy, as with any disease, could be personalized [208] . one recent study looked at various biomarker values as a more precise way of diagnosing. the biomarker molecules were classified according to their involvement into alveolar epithelial cell injury, fibroproliferation, and matrix remodeling as well as immune regulation. furthermore, genetic variants of tollip, muc-5b, and other genes associated with a differential response to treatment and with the development and/or the prognosis of ipf were identified. research into personalized medicine for treatment is starting [209] . although controversial, because of the lack of research on interpretation of the results, telomere length testing is available directly to consumers and through healthcare . fig. 51.11 antifibrosis therapy. the molecular mechanisms and therapeutic targets of natural products against fibrosis. a tgf-b exerts a profibrotic effect through smad-dependent [target (1)] and smadindependent pathways [target (2) ]. in the smad-dependent pathway, tgf-b1 directly phosphorylates and activates the downstream mediator smad2 and smad3 through tgf-b receptor i, and then smad2 and smad3 bind smad4, which forms a complex that moves into the nucleus and initiates gene transcription. smad7, transcribed by smad3, is a negative regulator of tgf-b/smad signaling, and the imbalance between smad3 and smad7 contributes to fibrosis. pi3k, erk, and p38 mapk are downstream mediators of the smad-independent tgf-b pathway. pparg [target (3)] could inhibit tgf-b to reduce fibrosis, while ctgf [target (4)], a matricellular protein, contributes to wound healing and virtually all fibrotic pathology. additionally, gas6 contributes to fibrosis through the tam receptor, which further activates the pi3k/akt pathway. similarly, lpa triggers fibrosis through the lpa1 receptor [target (5) ] that stimulates b-catenin to induce fibrogenesis. the activation of the hedgehog pathway [target (6) ] induces the transcriptional activity of gli to express target genes, which have an important role in interstitial fibrosis, undergoing myofibroblast transformation and proliferation. il pathway [target (7) ] stimulates nf-kb [target (8) ] to activate tgf-b to induce fibrogenesis, while nrf2 [target (9) ] antagonizes nf-kb activity to protect against fibrosis. b the chemical structures of isolated compounds and their therapeutic targets are presented. ctgf, connective tissue growth factor; il, interleukin; lrp, low-density lipoprotein receptor-related protein; ri, transforming growth factor-b receptor i; rii, transforming growth factor-b receptor ii; sara, smad anchor for receptor activation; stat, signal transducer and activator of transcription; tcf, t-cell factor; tgf, transforming growth factor. (reprinted from chen et al. [198] practitioners. there are a few different methods: quantitative polymerase chain reaction, or qpcr, which has a 20% variability rate, and flow cytometry and fluorescent in situ hybridization, or flow-fish, which has a 5% variability rate. most research labs use flow-fish for research. telomere length is a hot topic in research, the antiaging industry, and with popular health blogs. shorter-thanaverage telomeres have also been linked to heart disease and heart failure [163, 210, 211] , cancer [212] , diabetes [213] , and osteoporosis [214] . research has shown ways to slow telomere shortening. some include reducing stress, meditation, practicing loving kindness (a technique encouraging compassion) [215] , reducing exposure to air pollution and toxins [216] , cardiovascular exercise [217] , and a healthy fat and high vegetable diet [218, 219] . one study showed that 45 minutes of cardiovascular exercise three times per week resulted in longer telomeres representing 10 years of biological age, similar to those of marathon runners, compared to those who didn't exercise much or at all [220] . intermittent fasting, which reduces oxidative stress and keeps weight in check, has exploded in the scientific literature as a way to increase longevity and slow telomere shortening [221, 222] . nicotinamide adenine dinucleotide (nad+) supplements may also help maintain telomere length by activating sirtuins, the antiaging enzymes; parps, which are involved in dna repair; and cd38, which plays a role in insulin production. another supplement, cycloastragenol, derived from the herb astragalus, has also been shown to activate telomerase in mice. an ingredient called ta-65 has been derived and is used in supplements [223] . overall, a healthy lifestyle and diet seem to delay the shortening of telomeres. with relation to pf, the gene mutations involved in telomere shortening may or may not be influenced by the above interventions. more research is needed for this. pulmonary fibrosis is a devastating disease with no management or a known cure. the integrative and functional medicine nutritionist can help her/his patient by managing weight, encouraging a healthy diet full of anti-inflammatory foods and encouraging a healthy lifestyle with exercise and stress reduction. there is some promising research into natural supplement use to target the different areas of progression within the disease process and some ongoing drug and gene therapy development to follow. the prevalence of lung disease in the united states and worldwide is growing and will continue to grow rapidly with the deterioration of earth's atmosphere, which is caused by pollutants such as industrial and construction toxins and volcanic and wildfire particulates. poor maternal, childhood, and adult nutrition from micronutrient-poor diets resulting in nutrient insufficiencies, not necessarily nutrient deficiencies, is also contributing to increased lung disease diagnoses or poorer results during treatment [226, 227] . lifestyle choices and habits also play a role in the development of many of the lung diseases in today's world, such as smoking or vaping, which uses chemicals that are poorly studied to date. other lung diseases have their roots in genetics. some key processes drive many lung diseases, with the inflammatory process being the most important, according to current literature. nutrition can be of great help with inflammation, using a diet rich in whole foods providing micronutrients and phytonutrients. understanding genetics is also key to unraveling the causes and potential future treatments for many lung diseases. those patients with both genetic and environmental determinants, such as in those who smoke and have genes associated with copd, are at the greatest risk [228] . despite the prevalence of lung disease, there is a general lack of nutrition knowledge among practitioners, including familiarity with the research about the use of nutrition for prevention, slowing disease progression, or as a treatment of lung disease. historically, nutrition has been used in a supportive role, primarily monitoring macronutrients to prevent weight loss, muscle atrophy, and acid/alkaline balance. although this is extremely important, more attention needs to be directed toward emphasizing micronutrients and phytonutrients. research is strong regarding the benefits of vitamins, minerals, and pre-and probiotics, and indeed, some integrative and functional practitioners are using vitamin and mineral nutritional therapy in oral, intramuscular, and intravenous applications, when allowed, in practice. a newer area of research is around nutraceuticals, including targeted vitamins, minerals, and plantderived constituents concentrated to therapeutic doses. some exciting research around the use of curcumin and quercetin, for example, has been shown to dampen inflammation to the point of disrupting the disease process (see above). the expanding knowledge of the 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implications for depression management periostin: an emerging biomarker for allergic diseases zemaira® | alpha-1 antitrypsin deficiency diagnosis assessment of quality of life in children suffered from asthma identifying maternal conditions affecting altered embryologic development. neonatal advanced practice nursing: a case-based learning approach susceptibility for cigarette smoke-induced damp release and damp-induced inflammation in copd key: cord-294800-akr4f5p8 authors: kabir, md. tanvir; uddin, md. sahab; hossain, md. farhad; abdulhakim, jawaher a.; alam, md. asraful; ashraf, ghulam md; bungau, simona g.; bin-jumah, may n.; abdel-daim, mohamed m.; aleya, lotfi title: ncovid-19 pandemic: from molecular pathogenesis to potential investigational therapeutics date: 2020-07-10 journal: front cell dev biol doi: 10.3389/fcell.2020.00616 sha: doc_id: 294800 cord_uid: akr4f5p8 in december 2019, a severe acute respiratory syndrome coronavirus 2 (sars-cov-2)-related epidemic was first observed in wuhan, china. in 2020, owing to the highly infectious and deadly nature of the virus, this widespread novel coronavirus disease 2019 (ncovid-19) became a worldwide pandemic. studies have revealed that various environmental factors including temperature, humidity, and air pollution may also affect the transmission pattern of covid-19. unfortunately, still, there is no specific drug that has been validated in large-scale studies to treat patients with confirmed ncovid-19. however, remdesivir, an inhibitor of rna-dependent rna polymerase (rdrp), has appeared as an auspicious antiviral drug. currently, a large-scale study on remdesivir (i.e., 200 mg on first day, then 100 mg once/day) is ongoing to evaluate its clinical efficacy to treat ncovid-19. good antiviral activity against sars-cov-2 was not observed with the use of lopinavir/ritonavir (lpv/r). nonetheless, the combination of umifenovir and lpv/r was found to have better antiviral activity. furthermore, a combination of hydroxychloroquine (i.e., 200 mg 3 times/day) and azithromycin (i.e., 500 mg on first day, then 250 mg/day from day 2–5) also exhibited good activity. currently, there are also ongoing studies to evaluate the efficacy of teicoplanin and monoclonal and polyclonal antibodies against sars-cov-2. thus, in this article, we have analyzed the genetic diversity and molecular pathogenesis of ncovid-19. we also present possible therapeutic options for ncovid-19 patients. coronaviruses (covs) belong to the large family of positivesense, enveloped, highly diverse, and single-stranded rna viruses (fehr and perlman, 2015) . indeed, covs have been found to infect both humans and animals, therefore causing various respiratory, gastrointestinal, neuronal, and hepatic diseases (weiss and leibowitz, 2011; chan et al., 2013; zumla et al., 2016) . former epidemics of covs include severe acute respiratory syndrome (sars)-cov and middle east respiratory syndrome (mers)-cov, these outbreaks caused severe health problems in humans . a group of individuals was admitted to hospitals in late december of 2019 with a primary diagnosis of pneumonia due to an unknown cause (bogoch et al., 2020; lu et al., 2020) . it was assumed by the earlier reports that the onset of a potential cov epidemic provided the estimation of a reproduction number for the 2019 novel coronavirus (ncovid-19, named by world health organization (who) on feb 11, 2020) which was thought to be considerably >1 (ranges from 2.24-3.58) . this severe acute respiratory syndrome coronavirus 2 (sars-cov-2) can be transmitted largely via droplets and due to the close contact. it has been found that elderly people and individuals with chronic diseases or comorbidities are particularly high-risk populations (li et al., 2020a) . there are various symptoms of ncovid-19 including cough (68%), fever (88%), diarrhea (3.7%), and vomiting (5%) (mungroo et al., 2020) . the mode of transmission of sarscov-2 is supposed to take place from human to human through respiratory secretions released by the infected people when sneezing and coughing (mungroo et al., 2020) . ncovid-19 patients can be asymptomatic, which is making the control of the transmission more difficult (gao et al., 2020; li et al., 2020a) . since february of 2020, strict infection control approaches were executed by the centers for disease control (cdc) in order to limit the spread of sars-cov-2. in a recent study, mentioned that ncovid-19 patients had the highest viral load (measured in saliva samples) near presentation. they also summarized that as viral load is quite high during the time of hospital admissions, use of potent antiviral agents at an early stage might prove abbreviations: ace2, angiotensin converting enzyme 2; ap, antigen presentation; apcs, antigen presentation cells; apn, aminopeptidase n, arbs, angiotensin ii receptor blockers; ards, acute respiratory distress syndrome; cdc, centers for disease control; ncovid-19, novel coronavirus disease 2019; covs, coronaviruses; dpp4, dipeptidyl peptidase 4; dsrna, double-strand rna; ec 50 , half maximal effective concentration; ed, emergency department; elisa, enzymelinked immunosorbent assay; eua, emergency use authorization; fda, food and drug administration; ggo, ground-glass opacity; hcv, hepatitis c virus; hiv, human immunodeficiency virus;, mhc, major histocompatibility complex; or hla, human leukocyte antigen; icu, intensive care unit; il-6, interleukin 6; lpv/r, lopinavir/ritonavir; mabs, monoclonal antibodies; mers, middle east respiratory syndrome; n7-mtase, n7-methyltransferase; nsaids, nonsteroidal anti-inflammatory drugs; prrs, pattern recognition receptors; pui, patient under investigation; rdrp, rna-dependent rna polymerase; rsv, respiratory syncytial virus; s protein, spike protein; sam, s-adenosyl-methionine; sars, severe acute respiratory syndrome; sars-cov-2, severe acute respiratory syndrome coronavirus 2; tmprss2, transmembrane serine protease 2; who, world health organization. beneficial in managing the severity of ncovid-19 infection . previously, sars was found to be partially linked with environmental factors (lin et al., 2006) . in a study, it was revealed that air pollution was linked with mortality in sars patients in china (cui et al., 2003) . in this regard, it was mentioned that lung functions can be compromised owing to long-or shortterm exposure to certain environmental pollutants (cui et al., 2003) . air temperature is another factor that is also needed to be considered. it has been revealed by lin et al. (2006) that the occurrence of sars was much higher (18 times) at lower air temperatures as compared to higher temperatures. researchers also showed that respiratory disorders are more likely to take place in colder environments since virulence of agents are likely to deteriorate at higher air temperatures because they might not endure the alterations in the environment (d'amato et al., 2018) . in addition to this, they also summarized that sars-cov's transmissibility is comparable with the transmissibility of influenza virus. moreover, the occurrence of influenza markedly elevates with high relative humidity and low temperatures (park et al., 2020) , which is further suggesting that viral transmission can be significantly affected by environmental factors. there are no therapeutic agents that have been approved to treat ncovid-19. various medicines including immunomodulatory or antiviral drugs such as remdesivir, favipiravir, ribavirin, chloroquine, hydroxychloroquine, azithromycin, nitazoxanide, teicoplanin etc. have been advised as potential investigational drugs, many of which are now being studied in animals and humans who, 2020c) . on march 28, 2020, the food and drug administration (fda) gave an emergency use authorization (eua) for emergency use of oral administrations of chloroquine phosphate and hydroxychloroquine sulfate to treat sars-cov-2 infection (fda, 2020) . along with oxygen and mechanical ventilation, a guideline has also been published by belgium which involved recommendations from four other european countries, including switzerland, netherlands, france, and italy that recommended the use of remdesivir, lopinavir/ritonavir, tocilizumab, and chloroquine or hydroxychloroquine (sciensano, 2020) . in addition, japan and china approved the use of favipiravir (an antiviral agent) to treat influenza, which is now under investigation to treat ncovid-19 (fujifilm, 2020) . in this article, we have critically appraised the genetic diversity, molecular pathogenesis, symptoms, diagnosis, and prevention of ncovid-19. furthermore, we also specially reviewed the mechanisms, efficacy, and use of various drugs that might be beneficial in combating ncovid-19 infection. in nature, nucleotide substitution is considered as a vital step for viral evolution (lauring and andino, 2010) . the rapid spreading of sars-cov-2 raised a suspicion that mutations are driving its evolution. in a recent study, from gisaid, phan (2020a) collected 86 complete or near-complete sars-cov-2 genomes to estimate its genetic variation. in addition to this, these strains of sars-cov-2 were identified in patients with confirmed ncovid-19 from usa (11), china (50), japan (5), australia (5), england (2), singapore (3), france (4), germany (1), belgium (1), south korea (1), vietnam (1), and taiwan (2). clustalx2 was used to align the pair-wise nucleotide sequence (saitou and nei, 1987) . as a reference genome, the sequence of the strain "china/whu01/2020/epi_isl_406716" was used. interestingly, similar to other beta coronaviruses, the genome of sars-cov-2 contains a long orf1ab polyprotein at the 5 ′ end, followed by 4 main structural proteins, such as nucleocapsid protein, matrix protein, small envelope protein, and spike surface glycoprotein (phan, 2020b) . in addition to this, it was also observed that there were 3 deletions in the genomes of sars-cov-2 from australia (victoria), usa (wisconsin), and japan (aichi). in contrast, 1 deletion (10 nucleotides) was found in the 3 ′ end of the genome, while 2 deletions (2 nucleotides and 24 nucleotides) were found in the orf1ab polyprotein. furthermore, it was also observed from the nucleotide sequence alignment that there were 93 missense mutations in the entire genomes of novel coronavirus (table 1) . except for the envelope protein, 42 mutations were detected in all of the main structural and non-structural proteins. whereas, 4 missense mutations were observed in the nucleocapsid protein, 1 in the matrix protein, 29 in the orf1ab polyprotein, and 8 in the spike surface glycoprotein. interestingly 3 mutations (i.e., phe 367 , tyr 364 , and asp 354 ) were found in the spike surface glycoprotein receptor-binding domain. indeed, spike surface glycoprotein contributes significantly in binding to receptors on the host cell and eventually regulates host tropism (fung and liu, 2019) . furthermore, this spike glycoprotein is the main target of neutralizing antibodies . conformational changes of spike glycoprotein can be induced by the mutations, which can lead to altered antigenicity. up until now, no study has identified the amino acids that are involved in conformational alterations of spike glycoprotein. therefore, further studies are required to identify these important amino acids. various wild and domestic animals such as bats, cats, cattle, and camels might play a role as hosts for coronaviruses (adhikari et al., 2020) . in general, animal coronaviruses do not spread among human beings (cdc, 2020a) . nevertheless, exceptions have been noticed in case of mers and sars, where these diseases were found to be transmitted owing to the contact with respiratory droplets from sneezing or coughing of ncovid-19 patients. initial ncovid-19 patients were detected in china, where there was an association with the seafood market of wuhan, which is indicating that these initial infections took place because of the animal-to-person transmission. later on, ncovid-19 was also detected in healthcare professionals and also in other individuals where there was no history of contact with that affected area of wuhan, which is further suggesting the human-to-human transmission (gralinski and menachery, 2020; huang et al., 2020; li et al., 2020b; liu et al., 2020; who, 2020d) . as per the recent guidelines from health authorities of china (adhikari et al., 2020; who, 2020e) , there are 3 major routes of ncovid-19 transmission including droplets transmission, aerosol transmission, and contact transmission. transmissions via droplets were found to take place when respiratory droplets of infected individuals are inhaled or ingested by people who are in close contact. whereas, contact transmission might take place when a person touches a virus-contaminated-object or surface and then that person touches his/her nose, mouth, or eyes. on the other hand, aerosol transmission might take place when respiratory droplets mix into the air, thus forms aerosols and might result in infection when a high dose of aerosols are inhaled into the lungs in a comparatively closed environment (adhikari et al., 2020; who, 2020e) . in a study, it was revealed that the digestive system is also a possible route for sars-cov-2 transmission. symptoms like diarrhea and abdominal discomfort have been observed in individuals with confirmed ncovid-19, this observation led to studies which revealed that ace2 (to which sars-cov-2 binds) is highly expressed in enterocytes of colon and ileum . the effect of temperature on the health of humans can be varied depending on the countries or even areas (hajat and kosatky, 2010) . in line with this aforesaid finding, it was also reported that temperature can affect the transmission of respiratory syndromes-causing viruses including sars-cov-2 (ma et al., 2020) and influenza virus (park et al., 2020) . studies have also revealed that novel coronavirus and influenza virus can survive only in some specific environmental conditions and their transmissions also depend on temperatures (chan et al., 2011; jaakkola et al., 2014) , which is also applicable for sars-cov-2 transmission (wang et al., 2020c) . it was observed in case of influenza virus that it can transmit more readily at lower temperatures (lowen and steel, 2014) , since host immunity is likely to remain weakened in cold weather, this can further increase the vulnerability toward infection (kudo et al., 2019) . as the transmission process of coronaviruses is comparable with the influenza virus transmission (lin et al., 2006) , thus it can be expected that these processes are also applicable for the sars-cov-2 transmission (wang et al., 2020c) . several other environmental factors can affect the link between mortality and temperature including air pollution (cai et al., 2007) , humidity (jaakkola et al., 2014; kudo et al., 2019) , latitude (bao et al., 2016) . in this regard, socio-demographic factors including income, age, and gender (bao et al., 2016) have also been reported to play roles. in a study, chan et al. (2011) revealed that individuals who live at lower latitudes showed a strong adaptive capacity toward heat, and a relatively weak adaptive capacity was observed toward cold. these researchers also observed that the viability of sars-cov was much lower at higher relative humidity and higher temperatures (for example, relative humidity: over 95%, and temperature: 38 • c). in a different study, it was revealed that humidity and temperature are linked with an increased risk of ncovid-19 (wang et al., 2020c) . interestingly, coronaviruses can persist on inanimate surfaces including plastic, glass, or metal for up to 9 days (kampf et al., 2020) . ncovid-19 patients exhibit various clinical symptoms including cough, fever, fatigue, radiographic evidence of pneumonia, dyspnea, decreased or normal leukocyte counts, and myalgia . these aforesaid symptoms are also similar to mers-cov and sars-cov infections (peiris et al., 2004) . even though ncovid-19 pathogenesis is not well-understood, however the similar mechanisms used previously by mers-cov and sars-cov can provide a lot of information regarding sars-cov-2 pathogenesis (figure 1 ). spike protein (s protein) of coronavirus determines the viral entry into the host cells (de wit et al., 2016) . interestingly, the envelope spike glycoprotein binds to its cellular receptor, angiotensin converting enzyme 2 (ace2) for sars-cov (li et al., 2003b) and sars-cov-2 (figure 1) , dipeptidyl peptidase 4 for mers-cov (raj et al., 2013) , and cd209l for sars-cov [26] . although it was initially identified that sars-cov enters into cells by direct fusion of plasma membrane and virus (simmons et al., 2004) . however, belouzard et al. (2009) revealed that a vital proteolytic cleavage process takes place at sars-cov s protein at position (s2 ′ ) that facilitated the membrane fusion and infectivity of the virus. for membrane fusion, mers-cov also has evolved an aberrant 2 steps furin activation (mille and whittaker, 2014) . other than membrane fusion, entry of sars-cov was also found to be mediated by the clathrin-independent and -dependent endocytosis (wang et al., 2008; kuba et al., 2010) . following the entry of virus into the cells, rna genome of sars-cov is released into the cytoplasm and is translated into 2 polyproteins and structural proteins, subsequently the viral genome starts to replicate (perlman and netland, 2009 ). the newly generated envelope glycoproteins are then inserted into the membrane of the endoplasmic reticulum or golgi apparatus, and the it has been found that s protein is cleaved into s1 and s2 by a cell-derived protease, where s1 binds with ace2 receptor, and s2 is activated by the host serine protease tmprss2 and results in a fusion with the cell membrane. following the entry into the host cell, sars-cov-2 takeovers the host cell machinery to transcribe, replicate, and translate its rna genome and structural proteins before being reassembled, encapsulated, and exocytosed from the host cell. following exocytosis, sars-cov-2 is presented to host antigen presenting cells (apcs), which eventually leads to the generation of various cytokines including, tnf-α, cxcl-10, il-1, and il-6 (invivogen, 2020 when the sars-cov-2 enters into the cells, its antigen will be presented to the antigen presentation cells (apcs) (figure 1) , this process is crucial for the anti-viral immunity of the human body (kumar et al., 2020) . peptides of antigens are presented via major histocompatibility complex (mhc; or human leukocyte antigen (hla) in humans) and then identified by virusspecific cytotoxic t lymphocytes. therefore, the understanding of antigen presentation (ap) of the virus will provide a better understanding of the pathogenesis of ncovid-19. however, not much information is available regarding this, thus we can obtain information from previous studies on mers-cov and sars-cov. ap of sars-cov-2 mostly relies on mhc i molecules (liu et al., 2010) , nonetheless mhc ii also plays roles in its presentation. former studies revealed that many hla polymorphisms associate with the susceptibility of sars-cov, for instance hla-cw * 0801 (chen et al., 2006b) , hla-b * 0703, hla-dr b1 * 1202, and hla-b * 4601 (keicho et al., 2009) , while hla-a * 0201, hla-dr0301, and hla-cw1502 alleles are associated with the protection from sars infection (wang et al., 2011) . in case of mers-cov, it was observed that mhc ii molecules (for example hla-dqb1 * 02:0 and hla-drb1 * 11:01) were linked with the susceptibility to mers-cov infection (hajeer et al., 2016) . other than mannose-binding lectin gene polymorphisms linked with ap are associated with the risk of sars-cov infection (tu et al., 2015) . indeed, the aforementioned findings will give us an important idea regarding the mechanism, prevention, and treatment of ncovid-19. ap subsequently induces the human body's humoral and cellular immune responses, which are then facilitated via virus-specific b and t cells. like other common acute viral infections, antibodies including igg and igm are produced against sars-cov virus. it is estimated that at the end of week 12, sars-specific igm antibodies disappear. whereas, sars-specific igg antibody can stay for a longer period, which is suggesting that igg mainly has a protective function (li et al., 2003a) . furthermore, it was also found that sars-specific igg antibodies mainly are nspecific and s-specific antibodies (de wit et al., 2016) . most of the studies have focused on cellular immune responses, as compared to the humoral immune responses in case of coronavirus. recent findings have revealed that the levels of cd8 + and cd4 + t cells in the peripheral blood of ncovid-19 individuals were significantly decreased, as confirmed by increased percentages of cd38 (cd8 39.4%) and hla-dr (cd4 3.47%) double-positive fractions . likewise, acute phase response in individuals with ncovid-19 is linked with a marked decrease of cd8 + t and cd4 + t cells. interestingly, it was found that although there is no presence of antigen, cd8 + , and cd4 + memory t cells can last for 4 years in individuals who have recovered from sars-cov and can perform ifnγ generation, delayed-type hypersensitivity response and t cell proliferation (fan et al., 2009) . after 6 years of infection with sars-cov, specific t-cell memory responses to the sars-cov s peptide library can still be identified in 14 of 23 recovered sars individuals (tang et al., 2011) . in mouse models, specific cd8 + t cells also exhibited similar activity in the clearance of mers-cov (zhao et al., 2014) . indeed, these results might be useful in the rational designing of an effective vaccine against sars-cov-2. acute respiratory distress syndrome (ards) is considered as the major cause of ncovid-19-related death. in the early stages of the epidemic, 6 out of the 41 admitted patients with confirmed ncovid-19 died owing to ards . this ards is found to be the main immunopathological characteristic of sars-cov, mers-cov, and sars-cov-2 infections . cytokine storm is the major characteristic of ards. this storm is a fatal uncontrolled systemic inflammatory response that takes place because of the high secretions of chemokines (i.e., c-x-c motif chemokine 10 like sars-cov, mers patients showed increased levels of cxcl-10, cxcl8, ccl5, ifn-α, and interleukin 6 (il-6) in serum as compared to individuals with the mild to moderate disease (min et al., 2016) . in the human body, a powerful cytokine storm will induce an aggressive attack by the immune system, which will lead to multiple organ failure and ards, and will ultimately result in death in severe novel coronavirus infection, as like mers-cov and sars-cov infection . various strategies are used by viruses including sars-cov and mers-cov to evade immune responses for their better survival in host cells. the pattern recognition receptors (prrs) can identify the evolutionarily conserved microbial structures called pathogen-associated molecular patterns. nonetheless, mers-cov and sars-cov can stimulate the generation of doublemembrane vesicles lacking prrs and subsequently can replicate in these vesicles, thus evading the host detection of their doublestrand rna (dsrna) (snijder et al., 2006) . ifn-i (ifn-β and ifn-α) plays a protective function on mers-cov and sars-cov infection, however the ifn-i mechanism is suppressed in infected mouse models (channappanavar et al., 2016 (channappanavar et al., , 2019 . interestingly, by directly interacting with the dsrna, mers-cov's accessory protein 4a might block the stimulation of ifn at the level of melanoma differentiation-associated protein 5 activation (niemeyer et al., 2013) . ifn β promoter activation and transportation of ifn regulatory factor 3 to the nucleus can be inhibited by the orf5, orf4b, orf4a, and membrane proteins of mers-cov (yang et al., 2013) . sars-cov-2 can also affect the ap. in this regard, for instance, gene expression associated with ap is downregulated following mers-cov infection . therefore, it is vital to terminate the immune evasion of coronavirus to develop specific and effective therapies. following an incubation period of around 5.2 days, the symptoms of sars-cov-2 infection appear . it takes around 6 to 41 days from the first appearance of the symptoms to death, along with a median of 14 days (wang et al., 2020d) . however, the aforesaid durations depend on various factors including the patient's age and status of the immune system. this duration was found to be shorter for individuals older than 70-years old as compared to the individuals who are under the age of 70 (wang et al., 2020d) . at the onset of the disease, the most commonly observed symptoms are cough, fatigue, and fever (figure 2 ). in addition to this, various other symptoms including headache, lymphopenia, dyspnea, sputum production, diarrhea, and hemoptysis (graham carlos et al., 2020; huang et al., 2020; ren et al., 2020; wang et al., 2020d) . pneumonia has also been identified by computed tomography scan in ncovid-19 patients, unfortunately, various aberrant clinical features including ground-glass opacity (ggo), acute cardiac injury, and ards led to death . occasionally, in subpleural areas of both lungs, the multiple peripheral ggos were detected (lei et al., 2020) and these triggered both localized and systemic immune responses, which collectively raised the level of inflammation. unfortunately, treatment with interferon inhalation did not result in any clinical benefit, rather it aggravated the condition via facilitating pulmonary opacities (lei et al., 2020) . indeed, some of the symptoms of ncovid-19 are similar to the earlier betacoronavirus including dyspnea, dry cough, fever, and bilateral ggos . nonetheless, there are some unique clinical manifestations of ncovid-19 such as sore throat, sneezing, rhinorrhea (lee et al., 2003; assiri et al., 2013) . as revealed by chest radiographs following admission, in some cases it was observed that an infiltrate in lung's upper lobe is linked with growing dyspnea with hypoxemia (phan et al., 2020) . although ncovid-19 exhibited digestive disorders like diarrhea, only a small proportion of sars-cov or mers-cov showed similar gastrointestinal symptoms. thus, testing urine and fecal samples are important to eliminate a possible alternative mode of transmission (lee et al., 2003; assiri et al., 2013) . henceforth, developing methods to detect different routes of transmission for example urine and fecal samples are immediately required to develop ways to suppress and/or minimize the transmission and also to discover therapies to treat ncovid-19. recently, it has been observed that ncovid-19 might predispose to both arterial and venous thromboembolic disease because of immobilization, hypoxia, inflammation, and diffuse intravascular coagulation guan et al., 2020; klok et al., 2020; wang et al., 2020a; zhou et al., 2020) . furthermore, it was also revealed that respiratory failure in the disease is not only driven by the ards, rather microvascular thrombotic activities might also contribute in this regard (grillet et al., 2020) . therefore, klok et al. (2020) have strongly suggested to administer pharmacological agents in a prophylactic manner to all the intensive care unit (icu) ncovid-19 patients. for any given emergency department (ed) visiting patients with the symptoms of fever and respiratory diseases, healthcare workers must need to get a travel history in detail from that patient. if a patient shows flu-like symptoms and has a travel history to a country or area with confirmed ncovid-19 cases or if the patient came into close contact with a confirmed ncovid-19 patient in the last 14 days then the patient ought to be considered as a patient under investigation (pui) (npr, 2020) . it needs to be noted that here close contact means any individual who was within six feet of an individual with confirmed ncovid-19 for an extended period. furthermore, any individual who came into direct contact with the secretions of any ncovid-19 patient will also be considered as a close contact. individuals who have traveled from high-risk countries or areas with confirmed ncovid-19 cases and members of a family who are suffering from ncovid-19 and not staying at home care or not maintaining isolation precautions are regarded as highrisk exposures. while medium risk exposures involve individuals who have traveled from low-risk countries or areas and family members are stringently maintaining appropriate home care and adhering with proper isolation precautions (who, 2020e). in contrast, low-risk exposures involve those individuals who were in the same indoor environment (for example in a waiting hall) for a longer period with ncovid-19 patients but did not come into close contact. molecular assays of respiratory specimens are performed for diagnosis purposes usually at the regional referral laboratories designated by who (kaiser health news, 2020). for regional testing, the cdc started distributing ncovid-19 test kits on february 7 (who, 2020a). ncovid-19 test is getting more widely available day by day. for hospitals or institutions where ncovid-19 test is not available, the only option is the testing by cdc. ncovid-19 should be tested on an urgent basis for the pui cases. an individual should be removed from pui status only if that individual is fully evaluated clinically and has consulted with proper healthcare professionals. the mode of sars-cov-2 transmission is still complex. guidelines for ncovid-19 prevention is mainly based on the previously developed guidelines for sars and mers and also on the intervening guidelines provided by cdc and who (cdc, 2020a,b; who, 2020a) . before or upon arrival in ed, a pui ought to be identified by the hospitals to protect the healthcare professionals and other patients. prevention measures should involve maintaining hand and respiratory hygiene and also screening questions including travel history. following a pui identification, both local health department and hospital infection control ought to be immediately notified to avert further spread among healthcare professionals and other patients. a surgical mask must need to be given to any pui and need to be isolated in a private room or if possible in a negative pressure room (who, 2020a). as like sars and mers, ncovid-19 is also found to spread through the airborne route. therefore, surgical face masks might be beneficial to prevent sneeze and cough-related larger fluid droplets, however they are less likely to prevent small airborne contaminants (yee et al., 2020) . in this regard, respirators containing air filters and adequate seal should be more beneficial (tran et al., 2012; smith et al., 2016) . in healthcare settings, right use of respirators and personal protective equipment and proper hand hygiene are likely to prevent transmission (cowling et al., 2009; radonovich et al., 2019; yee et al., 2020) . if a patient requires hospital admission and there is no private or separate room for that patient, then that patient needs to be taken to an adequate facility containing institution. isolated rooms and care provide would need to be customized in a way that reduces the exposure of healthcare providers to the patient. indeed, along with an eye shield, all the healthcare providers must take measures to prevent contact with droplets and to maintain airborne precautions. since the risk of transmission is much higher during the aerosol-generating procedures (such as intubation), in these cases the importance of ppe is enormous (raboud et al., 2010; cdc, 2020a) . still, it remains not known, regarding how long ncovid-19 can stay airborne following a patient leaves the room. respiratory protection is essential to enter into the vacated room. since still there is no specific drug to treat ncovid-19, therefore the best approach will be taking preventative measures at a personal level including avoiding public transport, unnecessary travel, contact with ncovid-19 suspected individuals, and so on. indeed, the significance of maintaining frequent and proper hand hygiene is paramount. like other coronaviruses, sars-cov-2 has a lipid envelope, thus proper hand-washing with soap can break apart that lipid envelope and therefore can make it difficult or even impossible for the virus to infect humans. so far, this proper hand-washing is considered as the most effective preventative measure. in addition, duration of hand-washing with soap is also equally important. cdc has recommended that effective hand-washing should last at least for 20 s. in a study, borchgrevink et al. (2013) showed that out of 3,749 individuals in a college town environment, only 5% of those individuals properly followed the hand-washing rules (i.e., washing, rubbing, and rinsing). this finding indicates that there is a poor understanding of the significance of proper handwashing among the general people. therefore, awareness among people should be increased about the importance of frequent and proper hand-washing. in order to form a physical barrier, the who has recommended the use of a face mask by those individuals who are showing respiratory symptoms (who, 2020b). however, healthy people are not required to use face masks. a typical surgical mask only provides one-way protection and can avert the spreading of droplets during coughing and sneezing to the surrounding areas. healthcare professionals who are treating or in contact with a suspected or confirmed ncovid-19 patient must need to wear a specialized respirator (for example n95 or its equivalent) to effectively prevent the droplets entry and thus can reduce the chance of acquiring the infection (bae et al., 2020; who, 2020b) . strict precautionary measures must need to be taken by the individuals during handling affected individual's body secretions including sputum, urine, or stools (yeo et al., 2020) . remdesivir out of all the investigational drugs, remdesivir (figure 3) has appeared as the most effective and promising antiviral drug (li and de clercq, 2020) . this antiviral drug targets rnadependent rna polymerase (rdrp) of the virus while escaping proofreading via viral exoribonuclease, (agostini et al., 2018) which can ultimately lead to early termination of viral rna transcription as given in figure 4 . interestingly, remdesivir is a phosphoramidate prodrug and has a wide range of activities against numerous virus families, such as pneumoviridae, paramyxoviridae, filoviridae, and orthocoronavirinae (for example pathogenic mers-cov and sars-cov) (sheahan et al., 2017; martinez, 2020) . in a covid-19 mouse model, when remdesivir was administered prophylactically and as early therapeutic intervention, it significantly decreased the pulmonary viral load, which ultimately reduced the progression of the disease and significantly improved respiration (sheahan et al., 2017) . in tissue culture models, brown et al. revealed that remdesivir showed half-maximal effective concentration (ec 50 ) of 0.074 mm and 0.069 mm for mers-cov and sars-cov, successively . furthermore, remdesivir (within the submicromolar ec50s) also effectively inhibited zoonotic cov and human covs (hcov-229e and hcov-oc43) ko et al., 2020) . similar results were also observed when remdesivir was administered therapeutically (12 h post-inoculation) and prophylactically (24 h before prior inoculation) in mers animal (rhesus macaque) model (de wit et al., 2020) . even 2 amino acid substitutions (v553l and f476l) in the non-structural protein 12 polymerase were found to show lower-level of resistance toward remdesivir (agostini et al., 2018) . in humans, pharmacokinetic data of remdesivir is not available. however, it has been revealed in rhesus monkeys that intravenous remdesivir administration at the dose of 10 mg/kg increased the intracellular concentration (over 10 mm) of active triphosphate form in peripheral blood mononuclear cells for a minimum of 24 h, which is indicating its clinical significance in ncovid-19 treatment. furthermore, human safety data of remdesivir are available online (mulangu et al., 2019) . in usa, the first patient with confirmed ncovid-19 was effectively treated with remdesivir for the advancement of pneumonia on 7th day of hospital admission in january, 2020 (holshue et al., 2020) . moreover, to assess its efficacy and safety to treat individuals with confirmed ncovid-19, phase iii clinical trials (clinicaltrials.gov, 2020e) have been started in march 2020. in that study, individuals received 200 mg of remdesivir on first day, subsequently received 100 mg/day. although remdesivir showed promising in vitro and clinical activity against coronavirus (sheahan et al., 2017; holshue et al., 2020) , recently it has been reported that there are some uncertainties because of its multiple adverse effects including hepatotoxicity, rectal hemorrhage (jean et al., 2020b) . in japan, favipiravir (figure 3) was primarily developed and approved as an anti-influenza drug (shiraki and daikoku, 2020; wang et al., 2020b) . this antiviral drug has a wide range of activities against various rna viruses including rhinovirus, respiratory syncytial virus (rsv), and influenza. former studies revealed that favipiravir was successfully used to treat infections associated with rabies, lassa virus, and ebola virus (shiraki and daikoku, 2020) . furthermore, favipiravir was also found to be effective to treat severe fever with thrombocytopenia syndrome (shiraki and daikoku, 2020) . nevertheless, favipiravir was found to be ineffective against dna viruses. favipiravir is a potent antiviral drug that selectively suppresses the rdrp of rna viruses (figure 4) favipiravir is likely to produce resistant viruses, as compared to oseltamivir (shiraki and daikoku, 2020) . indeed, this feature of favipiravir can be beneficial in the treatment of ncovid-19. to treat influenza, favipiravir's recommended oral dose is 1,600 mg two times on first day, subsequently 600 mg twice/day from day 2 to 5, and 600 mg once/day on the sixth day. in recent times, initial findings of clinical trials have revealed that favipiravir exhibited significant activity in treating chinese ncovid-19 patients ( table 2 ) (xinhua news agency). in china, favipiravir has been approved to treat ncovid-19 in march 2020. furthermore, in china, randomized controlled trials involving ncovid-19 patients are also assessing the efficacy of favipiravir plus baloxavir marboxil (an antiviral drug) and favipiravir plus ifn-α (arab-zozani et al., 2020). ribavirin (figure 3) is a rdrp inhibitor (figure 4 ) used to treat various viral infections, for example, infections caused by rsv and hepatitis c virus (hcv) (ogawa and morisada, 2002) . it was revealed by in vitro studies that when ribavirin was administered at a concentration of 50 mg/ml, it showed effective antiviral activity against sars-cov (chan et al., 2015) . unfortunately, this antiviral drug was found to decrease the level of hemoglobin, therefore it can be detrimental for individuals with respiratory distress (martinez, 2020) . umifenovir umifenovir (figure 3) is a potent antiviral agent that has a wide-range of activities against various viruses including hcv, influenza a and b viruses (boriskin et al., 2008) . umifenovir's mechanism slightly varies with different viruses. it has been revealed that umifenovir suppresses the fusion of the virus with the host cell membrane (figure 4) , thus the subsequent viral entry into the host cell is inhibited (boriskin et al., 2008) . in a clinical trial, it has recently been observed that lopinavir/ritonavir (lpv/r, figure 3 ) protease inhibitors that are mainly used in human immunodeficiency virus (hiv) treatment did not significantly improve the ncovid-19 symptoms . furthermore, in a different study, effect of umifenovir plus lpv/r was compared with the sole treatment with lpv/r to treat ncovid-19 (deng et al., 2020) . the findings of that study revealed that better effects were observed with the treatment of umifenovir plus lpv/r in comparison with the sole lpv/r treatment (deng et al., 2020) . however, more studies are required to evaluate the incidence of resistance and efficacy. as coronavirus becomes activated on the membrane of the host cell, thus combination of lpv/r and umifenovir are likely to inhibit/prevent the viral entry into the host cell (figure 4) . besides, there is also a need regarding a better chloroquine chloroquine (figure 3) is mainly used as an antimalarial drug. furthermore, chloroquine is also used to treat various autoimmune disorders including rheumatoid arthritis and lupus erythematosus. in an animal model, it has recently been observed that chloroquine can also play a role as a potent antiviral drug against various viruses including influenza h5n1 (yan et al., 2013) . interestingly, chloroquine can prevent the viral fusion with the cell membrane of host cell by increasing endosomal ph (figure 4) . glycosylation of sars-cov's cellular receptors can also be interfered by chloroquine (vincent et al., 2005; wang et al., 2020b) . even though findings from in vitro studies regarding chloroquine is auspicious (ec 90 = 6.90 mm, used ncovid-19-infected vero e6 cells), however use of chloroquine to treat ncovid-19 infection is a completely off-label use. furthermore, this drug is not strongly indicated due to some of its safety reasons including qt prolongation with ventricular dysrhythmia and adverse reactions on the renal, hepatic, and hematologic systems (cortegiani et al., 2020) . hydroxychloroquine (a chloroquine derivative, figure 3 ) is also mainly used as antimalarial and anti-inflammatory drugs (sinha and balayla, 2020) . it has been proposed that hydroxychloroquine controls cytokine storm (figure 4) , which takes place in critically ill late phase ncovid-19 patients (yao et al., 2020) . as compared to chloroquine, hydroxychloroquine is more potent and their ec 50 values are 5.47 and 0.72, successively. in addition to this, hydroxychloroquine is less likely to interact with other drugs as compared to chloroquine. moreover, in comparison with chloroquine phosphate, pharmacokinetic data confirmed that hydroxychloroquine is much more effective (5 days before) at inhibiting sars-cov-2 in vitro (yao et al., 2020) . it has been declared on march 26, 2020 by taiwan cdc that hydroxychloroquine has a significant role in the treatment of ncovid-19 patients. however, treatment with hydroxychloroquine is contraindicated for the patients who are pregnant or breastfeeding, allergic to hydroxychloroquine, glucose-6-phosphatase deficient, and for individuals with prolonged qt interval in electrocardiograms and retinopathy (gautret et al., 2020) . azithromycin previously, azithromycin (figure 3) showed excellent in vitro activity against ebola virus (madrid et al., 2016) . it was found that azithromycin was administered to individuals with viral infection, it prevented severe infections of respiratory tract in pre-school children (bacharier et al., 2015) . in a recent study, when azithromycin was administered (i.e., 500 mg on first day, then 250 mg per day from day 2-5), it remarkably reinforced the hydroxychloroquine's efficacy (when 200 mg was administered 3 times/day for 10 days) to treat 20 severely ill ncovid-19 patients (figure 4) . the mean serum concentration of hydroxychloroquine was 0.46 ± 0.20 mg/ml. it is assumed that this excellent virus eliminating activity was achieved owing to the use of the aforesaid combination therapy (gautret et al., 2020) . therefore, use of azithromycin along with hydroxychloroquine can be an effective future alternative to remdesivir in ncovid-19 treatment. however, in this regard, a possible complication related to prolonged qt interval should be taken into consideration. teicoplanin is a glycopeptide antibiotic and it has been revealed by zhou et al. (zhou et al., 2016 ) that teicoplanin exerted inhibitory activity (ic 50 as low as 330 nm) against replication-and transcription-competent virus-like particles. studies confirmed that teicoplanin can suppress the entry of mers and sars envelope pseudotyped viruses zhou et al., 2016) . in terms of its mechanism, teicoplanin can selectively suppress the effects of cathepsins b and l in host cell. these proteases are involved with cleaving the viral glycoprotein permitting exposure of the receptor-binding domain of its core genome and then release into the cytoplasm of host cells (zhou et al., 2016; baron et al., 2020) . therefore, teicoplanin blocked the entry of ebola virus in the late endosomal pathway. also, the derivatives of teicoplanin including telavancin, dalbavancin, and oritavancin, were also found to block the entry of sars, mers, and ebola viruses (zhou et al., 2016) . collectively, these findings suggest that teicoplanin and its derivatives might play a vital role in inhibiting the viruses that are dependent on cathepsin l ( table 2) . ivermectin ivermectin (figure 3) is an antiparasitic agent and it has broadspectrum of activity (caly et al., 2020) , recent in vitro studies have revealed that this drug also has an antiviral effect against dengue and hiv viruses . it has been found that the preformed impα/β1 heterodimer is accountable for the transport of viral protein into the nucleus and ivermectin can dissociate this heterodimer. since this transport of viral protein into the nucleus is important for the replication cycle and suppression of the host's antiviral response, thus targeting this viral protein transport might prove as a significant target in the development of therapeutic agents against rna viruses (caly et al., 2012; yang et al., 2020a) . following 48 h of ncovid-19 infection, a recent in vivo study has been demonstrated that ivermectin can decrease the level of viral rna (figure 4 ) up to 5,000-times (caly et al., 2020) . since ivermectin has an established safety profile as an antiparasitic agent, thus now it is needed to establish a safe and effective dose of this drug in clinical trials to treat ncovid-19 infection. nitazoxanide (figure 3) is an effective antiparasitic and antiviral drug (rossignol, 2016) . this drug has a broad-spectrum in vitro antiviral activity against a range of viruses including rsv, rotavirus, parainfluenza, influenza, and coronavirus (rossignol, 2016) . in vero-e6 cells, nitazoxanide exerted a potent in vitro antiviral activity against sars cov-2 (ec 50 = 2.12 µm, at 48 h) . furthermore, this strong antiviral effect is in line with the observed ec 50 values for nitazoxanide (ec 50 = 0.92 µm) and tizoxanide (an active metabolite of nitazoxanide) (ec 50 = 0.83 µm) against mers-cov in llc-mk2 cells (rossignol, 2016) . in terms of its mechanism of action, it is believed that nitazoxanide has potent antiviral effect because of its ability to interfere with the host-regulated pathways associated with viral replication instead of the virus-specific pathways (rossignol, 2016) . therefore, studies were carried out to evaluate the ability of this drug to treat influenza and other related acute respiratory infections. in the phase iib/iii of a clinical trial, positive effects of nitazoxanide were observed in the management of influenza symptoms, where 600 mg of nitazoxanide was orally administered twice a day (haffizulla et al., 2014) . unfortunately, in phase ii clinical trial it was observed that nitazoxanide neither alleviated the symptoms nor decrease the length of stay in hospitals of individuals infected with respiratory viruses (gamiño-arroyo et al., 2019). however, in vitro data regarding the activity of nitazoxanide against coronavirus is promising. therefore, further studies are required to estimate its potential in ncovid-19 treatment. baricitinib most commonly used in rheumatoid arthritis treatment. this drug is a reversible and selective inhibitor of janus kinase 1 (jak1) and jak2. it has been found that these latter mentioned enzymes transduce intracellular signals for growth factors and cytokines associated with immune response, inflammation, and haematopoiesis. moreover, this jak inhibitor blocks the activities of ap2-associated with protein kinase 1, which ultimately prevents viral binding with the alveolar epithelium (mayence and vanden eynde, 2019) . it has also been indicated that baricitinib might be used as an additional therapy for the covid-19 treatment (richardson et al., 2020) . in order to determine the safety and efficacy of sarilumab, hydroxychloroquine, lopinavir/ritonavir, and baricitinib to treat 1,000 hospitalized covid-19 patients, a non-randomized phase ii clinical study has recently been started (scavone et al., 2020) . other selective jak inhibitors including ruxolitinib, fedratinib, and sunitinib might also be effective against covid-19 in decreasing endocytosis of virus, inflammation, and levels of cytokines including il-6 and ifn-γ (bekerman et al., 2017; clinicaltrials.gov, 2020f; favalli et al., 2020; scavone et al., 2020; stebbing et al., 2020) . previously, convalescent plasma therapy was used as a terminal therapy to increase the survival rate of individuals with a range of viral infections including sars, severe infection caused by ebola virus, pandemic 2009 influenza a h1n1, h5n1 avian influenza shen et al., 2020) . convalescent plasma therapy can be effective because viremia can be suppressed due to the presence of plasma immunoglobulin antibodies in recovering patients. in a study, shen et al. (2020) evaluated the effect of convalescent plasma therapy in 5 severely ill ncovid-19 patients with ards. in that study, convalescent plasma was transfused in those patients with a novel coronavirus-specific antibody (neutralization titer >40 and binding titer > 1:1000). the used convalescent plasma of that study was obtained from five ncovid-19-recovered individuals. the obtained convalescent plasma was then administered to the 5 patients (in between 10 and 22 days following admission) along with methylprednisolone and antiviral drugs. after convalescent plasma transfusion, clinical conditions of the patients were found to be improved, including decreased viral loads (patients became ncovid-19 negative within 12 days), elevated level of sars-cov-2-specific enzyme-linked immunosorbent assay (elisa), neutralizing antibody titers, normalized body temperature (within 3 days in four/five patients), improved ards (four patients at 12 days following transfusion), successful weaning from mechanical ventilation (three participating individuals within 2 weeks of therapy), increased partial pressure of oxygen/fraction of inspired oxygen, and reduced score in sequential organ failure assessment. out of the 5 participants, 2 of them were in stable condition (at 37 days following transfusions), while 3 of them were discharged from the hospital (following 51, 53, and 55 days of staying in the hospital) (shen et al., 2020) . finally, the researchers summarized that although there were a small number of participants in this study, they suggested the therapy with convalescent plasma can be effective in the ncovid-19 treatment (shen et al., 2020) . as a prophylactic measure and therapy, monoclonal and polyclonal antibodies (targeting hemagglutinin binding) have been recommended to treat various viral infections including influenza (beigel et al., 2019) . the effectiveness of these antibodies against mers-cov largely encouraged the recent efforts to develop monoclonal and polyclonal antibodies against coronaviruses (sheahan et al., 2017) . for instance, in a phase i trial, sab-301 (a human polyclonal antibody) which was produced in transchromosomic cattle was found to be safe and better tolerated in healthy participants (beigel et al., 2019) . in a study, cockrell et al. (2016) revealed in mouse models that human monoclonal antibodies (mabs)-based immunotherapy only mediated protection in the early stage of mers (martinez, 2020) . many in vitro analyses showed that s protein of sars-cov is crucial to mediate the viral entry into the host cells. in addition to this, the cleavage and subsequent activation of the s protein of sars-cov via a host cell's protease is vital for the entry of the virus (glowacka et al., 2011) . in cell cultures, it has been noticed that transmembrane serine protease 2 (tmprss2) is a vital protease of host cells that causes activation of s protein of sars-cov, therefore it was studied as an important target for antiviral drugs (sheahan et al., 2017) . previously, camostat mesylate (an inhibitor of serine protease) showed inhibitory activity against tmprss2 (kawase et al., 2012) . furthermore, k11777 (a cysteine protease inhibitor) exhibited significant inhibitory activity (at submicromolar range) against replication of mers-cov and sars-cov (zhou et al., 2015) . sarilumab is a human monoclonal antibody and 3 clinical trials are ongoing to assess the safety and efficacy of this antibody (alone or along with other standard therapies) in nearly 1,500 covid-19 patients (clinicaltrials.gov, 2020a,d,f; scavone et al., 2020) . eculizumab (a monoclonal antibody) is approved to treat neuromyelitis spectrum disorders, refractory generalized myasthenia gravis, and atypical hemolytic uraemic syndrome. this monoclonal antibody inhibits the terminal portion of the inflammatory response-associated complement cascade. although the function of the complement cascade in ncovid-19 pathogenesis is not clear, numerous studies revealed that its suppression may effectively function as a therapeutic technique (ip et al., 2005; yuan et al., 2005; gralinski et al., 2018) . due to these findings, eculizumab will be tested in the solid-c19 clinical trial to treat individuals with severe ards and ncovid-19 (clinicaltrials.gov, 2020b). currently, emapalumab (a monoclonal antibody) is being studied in an openlabel, randomized, phase ii/iii study to evaluate the safety and efficacy of this antibody in decreasing respiratory distress and hyper-inflammation in ncovid-19 patients (clinicaltrials.gov, 2020c) . in china, stem cells are currently being studied as a treatment for ncovid-19. tocilizumab (a mab) is an immunosuppressive agent and is used to treat rheumatoid arthritis (kaneko, 2013) . this agent was designed to suppress the il-6 binding with its receptors to alleviate cytokine storm syndrome. tocilizumab is now being studied as a potential ncovid-19 treatment (jean et al., 2020b; slater, 2020) . in ncovid-19 high-risk populations, traditional chinese medicines were also regarded as a preventative measure, based on the traditional uses and anecdotal evidence of prevention of h1n1 pdm09 and sars. nonetheless, there is a lacking of clinical data regarding the effectiveness of these herbal medicines as an ncovid-19 treatment (cunningham et al., 2020; luo et al., 2020) . in china, several traditional medicines were widely used during the ncovid-19 epidemic and 6 of these herbal medicines include lianqiao (fructus forsythia), jinyinhua (lonicerae japonicae flos), gancao (glycyrrhizae radix et rhizoma), baizhu (atractylodis macrocephalae rhizoma, rhizome of atractylodes macrocephala koidz), fangfeng (saposhnikoviae radix, dried root from the perennial herb saposhnikovia divaricate), and huangqi (astragali radix, dried root of astragalus membranaceus bge. var. mongholicus). indeed, stringent clinical studies are required with a large number of participants to demonstrate the preventive role of these traditional chinese medicines (cunningham et al., 2020; luo et al., 2020) . the occurrence of co-infection can widely vary among the patients with confirmed ncovid-19. various reports suggest that several co-pathogens including viruses (such as rhinovirus, influenza, and hiv) and bacteria (for example candida species, mycoplasma pneumonia) can co-exist in these patients. among them, influenza a virus was most commonly found to coexist (jean et al., 2020b) . furthermore, ncovid-19 patients with pneumonia were found to be commonly treated by the coadministration of anti-influenza drugs and antibiotics (jean et al., 2020b) . therefore, careful selection of potential broadspectrum antibiotic(s) is required for the long-stay (over 6 days) hospitalized patients (chou et al., 2019; jean et al., 2020a) . mixed clinical findings were observed with the use of corticosteroids to treat sars-cov infections. although various reports suggested that there was no significant contribution of corticosteroids in clinical outcomes (stockman et al., 2006) . in contrast, it was suggested by a report that decreased mortality rate was observed due to the use of corticosteroids in critically ill patients (chen et al., 2006a; wu et al., 2020a) . unfortunately, several reports suggested worse outcomes including longer time for viral clearance, or elevated composite endpoint of icu admission or even death, owing to the use of corticosteroids (auyeung et al., 2005) . in a cohort (n = 309), a longer time in viral clearance was observed in the corticosteroids-receiving mers-cov patients (arabi et al., 2018) . nevertheless, in the same study, it was observed that there was an insignificant decrease in 90-day mortality in corticosteroids-receiving patients. recent reports suggested that there was a decreased rate of mortality in ncovid-19 patients with ards due to the use of corticosteroids (wu et al., 2020a) . these findings suggest that use of corticosteroids resulted in inconsistent outcomes. however, corticosteroids might be beneficial for patients with cytokine-linked lung injury and those who might rapidly develop progressive pneumonia . indeed, healthcare professionals need to carefully assess the risk and benefit ratio of corticosteroid use for each patient. this necessity to assess risk and benefit of corticosteroid use in individual patients and its careful dose consideration has been demonstrated in diagnosis and treatment guidelines from china's national health commission. as per that guideline, glucocorticoid (equivalent to methylprednisolone 1-2 mg/kg per day for three-five days or less) may be considered based on chest imaging and respiratory distress. large-dose of glucocorticoids can suppress the immune system, this can result in delayed sars-cov-2 clearance (mccreary and pogue, 2020) . recently, chinese thoracic society recommended a lower dose of methylprednisolone (≤ 0.5-1 mg/kg per day) for a maximum of 7 days in selected patients, prior to treatment these selected patients should be carefully assessed for potential risks and benefits . more clinical studies are immediately required to elucidate the function of corticosteroids in ncovid-19. in a study, yang et al. (2020b) mentioned that diabetes and cerebrovascular diseases were the commonly observed comorbidities in the non-survivors of ncovid-19 in icus. furthermore, guan et al. (2020) also observed similar results in their study and these ncovid-19 patients received angiotensin ii receptor blockers (arbs) or ace inhibitors. indeed, sars-cov-2 and sars-cov can bind with the ace2 receptors on the epithelial cells of lung, kidney, and intestine (fang et al., 2020) . therefore, when ards is not present, arb or ace inhibitors can be administered to ncovid-19 patients. increased activity of ace2 was found to be linked with decreased severity of ards among individuals with rsv-caused lower respiratory tract infection (wösten-van asperen et al., 2013) . interestingly, fedson (2016) revealed in their study that statins mainly target host response to infection, instead of the virus itself. these researchers also indicated that combination therapy with statins and arb may induce the reversal of homeostatic processes, which will allow the self-recovery of individuals (fedson et al., 2020) . there is an argument regarding the usage of non-steroidal anti-inflammatory drugs (nsaids) like ibuprofen since it can increase the ace2 receptors (day, 2020) . if the severely ill ncovid-19 individuals suffer from fever, acetaminophen can be a good option to control body temperature as compared to other nsaids (therapeutics initiative, 2020). tang et al. (2020) confirmed that anticoagulant therapy by heparin (an anticoagulant) specially with low molecular weight heparin improved the prognosis in severely ill patients with ncovid-19. furthermore, 28-day mortality of heparin receivers was found to be lower as compared to the non-users among individuals with sepsis-stimulated coagulopathy scores 4 or ddimer > 6-times the upper limit of normal . in human body, vitamin a plays various important functions including protecting mucosal and epithelium integrity, mediating growth and development, and proper maintenance of vision (huang et al., 2018) . vitamin a is also essential for enhancing immune response and maintaining regulatory action in both humoral and cellular immune responses (huang et al., 2018) . in case of infants, supplementation with vitamin a was found to ameliorate antibody response following several vaccines including anti-rabies (siddiqui et al., 2001) and measles vaccination (huang et al., 2018) . moreover, an improved immune response to influenza virus vaccination has also been reported in children (2-8 years) who had a deficiency of vitamin a and d at baseline, following supplementation with vitamin a and d (patel et al., 2019) . vitamin d has a significant contribution in modifying both adaptive and innate immune responses (aranow, 2011) . it has been revealed by epidemiological studies that there is a link between deficiency of vitamin d and elevated susceptibility to acute viral respiratory infections (monlezun et al., 2015) . it has also been suggested that vitamin d significantly modulates the innate immune responses against various viral respiratory infections including rsv, parainfluenza 1 and 2, and influenza a and b (zdrenghea et al., 2017) . indeed, studies have revealed that there is a strong relationship between vitamin d deficiency and elevated risk of both lower and upper respiratory tract infections (jolliffe et al., 2013) . nonetheless, conflicting and heterogeneity in dosage regimens and baseline vitamin d conditions in study populations were observed in randomized controlled trials (rcts) (jolliffe et al., 2013) . in a study, aglipay et al. (2017) observed no significant difference between the action of high-dose (2000 iu per day) vs. standard-dose (400 iu per day) vitamin d supplementation on viral upper respiratory tract infections (aglipay et al., 2017) . nevertheless, only one-third of the study subjects received vitamin d at doses below 30 ng/ml. vitamin d increased the plasma level of tgfβ without ameliorating antibody generation in a rct on the effect of vitamin d administration on influenza vaccine response in deficient elderly person (goncalves-mendes et al., 2019) . in addition to this, it was also indicated in the latter mentioned rct that vitamin d administration perhaps directed the polarization of lymphocyte toward a tolerogenic immune response (goncalves-mendes et al., 2019) . in a different rct, monthly administration of high-dose of vitamin d (100,000 iu/month) decreased the occurrence of acute respiratory infections in older long-term care residents as compared to a standard dose group (12,000 iu/month) (ginde et al., 2017) . therefore, it is quite clear that the effect of vitamin d on antiviral immunity against respiratory infections is dependent on an individual's vitamin d status. moreover, it has been confirmed that vitamin d supplementation is also useful in case of other viral infections, for instance, vitamin d addition to conventional peg-α-2b/ribavirin therapy for treatment-naive individuals with chronic hcv genotype 1 infection considerably ameliorated the viral response (abu-mouch et al., 2011) , and similar action was also seen in individuals with hcv genotype 2-3 (nimer and mouch, 2012) . vitamin e possesses strong antioxidant property and it can modify host immune responses [14] . the deficiency of this vitamin can lead to impairment of both cellular and humoral immune responses (moriguchi and muraga, 2000) . some studies revealed that administration of vitamin e may exert harmful activities in case of infectious disease. vitamin e increased the risk of pneumonia among 50-69 years old adult smokers (hemilä and kaprio, 2008) . similarly, vitamin e supplementation (200 iu/day) did not significantly reduce the respiratory tract infections in elderly nursing facility residents (meydani et al., 2004) . nevertheless, in a small pilot rct, positive activities of vitamin e were seen in the treatment of chronic hepatitis b, where vitamin e administration markedly normalized the liver enzymes and hbv-dna negativization (andreone et al., 2001) . similarly, in a rct, vitamin e supplementation increased anti-hbe seroconversion and virological response in the pediatric population (fiorino et al., 2017) . vitamin c plays a significant role as an enzymatic cofactor in numerous physiological reactions including immune potentiation, collagen synthesis, and hormone generation . in mouse models, it was revealed that vitamin c plays important role in the antiviral immune responses against the influenza a virus (h3n2) via the elevated generation of ifn-α/β, particularly at the early stages of infection . nonetheless, no significant benefit has been observed in using mega-dose of vitamin c as a prophylactic measure to lower the incidence of common cold caused by viral infections (hemilä and chalker, 2013) . zinc (an essential trace element) contributes significantly in the growth, development, and maintenance of immune responses (prasad, 2013; read et al., 2019) . the deficiency of zinc is linked with an enhanced susceptibility toward infectious diseases, for example, viral infections. an individual's zinc status is a vital factor that can affect the immune response against viral infections. indeed, zinc-deficient individuals are at greater risk of developing infections including hcv or hiv (read et al., 2019) . acevedo-murillo et al. (2019) reported that there was a noticeable clinical improvement in the 103 children (1 month−5 years) with pneumonia in the zinc-receiving group as compared to placebo (acevedo-murillo et al., 2019) . the researchers also confirmed that there was a rise in the cytokine response in th1 pattern (inf-γ and il-2) only in the zinc-receiving group, along with th2 cytokines (il-10 and il-4) being increased or remained elevated in both groups. following stem cell transplantation, oral administration of a high dose of zinc (150 mg/day) increased thymic activity and output of new cd4 + naive t cells, which eventually helped in the prevention of torque teno virus reactivation (iovino et al., 2018) . nonetheless, provinciali et al. (1998) summarized that prolonged administration of zinc (400 mg/day) or zinc plus arginine (4 d/day) in the elderly (age 64-100 years) people restored zinc concentrations in plasma, which was ineffective in stimulating or improving the antibody response or number of cd3, cd4, or cd8 lymphocytes following influenza vaccination. selenium (a trace element) also exerts a range of important functions including antioxidant effects, various pleiotropic activities, and anti-inflammatory effects (rayman, 2012) . selenium deficiency is found to be linked with cognitive impairment, poor immune response, and elevated risk of mortality, whereas an increased level of selenium or treatment with selenium has exhibited antiviral actions (rayman, 2012) . broome et al. (2004) assessed whether an increased selenium administration (50-100 µg/day) ameliorated immune response in adults with a borderline concentration of selenium (broome et al., 2004) . treatment with selenium elevated the plasma selenium levels, and also increased the activities of cytosolic glutathione peroxidase and lymphocyte phospholipid. furthermore, selenium also increased the cellular immune responses (elevated level of ifn-γ and other cytokines), along with an increased level of t-helper cells and earlier peak tcell proliferation. nonetheless, it was observed that humoral immune responses were not affected (broome et al., 2004) . moreover, selenium treatment in participants also induced rapid poliovirus clearance. copper (another essential trace element) has a significant contribution in the differentiation and development of immune cells (li et al., 2019) . it has also been confirmed that copper exerted in vitro antiviral effects. intracellular copper was found to regulate the life cycle of influenza virus (rupp et al., 2017) , while thujaplicin-copper chelates inhibited the replication of human influenza viruses (miyamoto et al., 1998) . in a study, turnlund et al. (2004) determined the effects of chronic administration of copper on immune response, oxidative stress, and indices of copper status. these researchers observed that when copper was administered at a dose of 7.8 mg/day, copper significantly increased the level of superoxide dismutase, benzylamine oxidase, and plasma ceruloplasmin activity as compared to 1.6 mg/day dose, which further suggesting an enhancement in antioxidant status. nonetheless, increased copper administration (7.8 mg/day) markedly decreased the proportion of antibody titer, serum il-2r, and circulating neutrophils against the beijing strain of influenza (turnlund et al., 2004) . magnesium (an essential mineral) has a significant contribution in regulating immune response via significantly affecting the t helper-b cell adherence, macrophage response to lymphokines, immunoglobulin m (igm) lymphocyte binding, adherence with immune cells, antibody-dependent cytolysis, and immunoglobulin synthesis (liang et al., 2012) . it has also been reported in in vivo and in-vitro studies that magnesium may have a contribution in the immune function against viral infections (chaigne-delalande et al., 2013) . still now there is no specific antiviral drug to treat ncovid-19, but some of the investigational drugs were found to be useful. various drugs are being analyzed in vitro studies or clinical trials. although ribavirin is a potent antiviral drug, its clinical effects are not clear and its side effects ought to be carefully considered. on the other hand, chloroquine has been studied in 15 interventional studies. furthermore, in the chinese clinical trial registry, the derivatives of chloroquine were prospectively registered; and more studies are required to evaluate their antiviral effects and to estimate the recommended dose in ncovid-19 patients . along with antiviral drugs, glucocorticoids ought to be utilized carefully and in a timely manner in ncovid-19 patients. in addition to this, extracorporeal support need to be considered under strict contraindications and indications, otherwise, there will be numerous additional complications and also a waste of resources . in order to manage the current ncovid-19 outbreak, extensive measures are needed to be taken to lower the personto-person transmission of the virus. in addition to this, special efforts and attention are required to reduce or protect the susceptible populations such as elderly people, health care providers, and children. more studies are also essential to understand the mechanisms related to ncovid-19 pathogenesis. this better understanding will help the development of specific and effective therapies against sars-cov-2. since the respiratory tract is mainly affected by sars-cov-2, thus special consideration is required to deliver the drug into the respiratory tract. more studies in animals and clinical trials on drug repositioning can also be considered to identify potential drugs to treat ncovid-19. still there is no available specific drug or vaccine to treat ncovid-19, thus effective preventative measures are recommended. specific drugs are urgently required to inhibit the entry of the virus and subsequent replication to overcome this outbreak. currently, as mentioned in this article, multiple investigational drugs and clinical trials are ongoing. the discovery of new drugs will ultimately enable us to better control this outbreak. furthermore, in silico studies can also be considered to faster the drug development process. finally, sharing findings or data will be effective to fight against ncovid-19 globally. mk and mu conceived the original idea and designed the outlines of the study and prepared the figures for the manuscript. mk wrote the initial draft of the manuscript. mu revised and improved the draft. mh, ja, ma, ga, sb, mb-j, ma-d, and la participated in the literature review of the manuscript. all authors have read and approved the final manuscript. vitamin d supplementation improves 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the early phase of the outbreak clinical course and risk factors for mortality of adult inpatients with covid-19 in wuhan, china: a retrospective cohort study glycopeptide antibiotics potently inhibit cathepsin l in the late endosome/lysosome and block the entry of ebola virus, middle east respiratory syndrome coronavirus (mers-cov), and severe acute respiratory syndrome coronavirus (sars-cov) protease inhibitors targeting coronavirus and filovirus entry coronaviruses-drug discovery and therapeutic options the authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.copyright © 2020 kabir, uddin, hossain, abdulhakim, alam, ashraf, bungau, bin-jumah, abdel-daim and aleya. this is an open-access article distributed under the terms of the creative commons attribution license (cc by). the use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. no use, distribution or reproduction is permitted which does not comply with these terms. key: cord-020493-ddo3a7wq authors: nan title: infusionstherapie und ernährung von risikogruppen date: 2005 journal: infusionstherapie und di&#x000e4;tetik in der p&#x000e4;diatrie doi: 10.1007/3-540-27897-4_9 sha: doc_id: 20493 cord_uid: ddo3a7wq besondere situationen erfordern ein besonderes vorgehen spezifische physiologie von patientengruppen (z. b. frühoder neugeborene), auswirkungen von therapeutischen maßnahmen (z. b. operationen), pathophysiologie von erkrankungen (z. b. angeborene stoffwechselerkrankungen, erkrankungen des onkologischen, rheumatischen oder atopischen formenkreises, anorexia nervosa, bulimie oder adipositas) oder; besondere körperliche belastungen [z. b. (leistungs-)sport]. bekannte strategien werden systematisch und prägnant dargestellt und diskutiert. die beschäftigung mit der ernährung von »risikogruppen« übt das erkennen und den umgang von potenziellen gefahrensituationen bei der verordnung von bilanzierter ernährung. so sollte auch derjenige von dem kapitel profitieren, der sich mit den behandelten patientengruppen, situationen, erkrankungen üblicherweise nicht beschäftigen muss. ahornsirupkrankheit -245 8.4. 5 mittelketten-coa-dehydrogenase-defekt -253 8.4. 6 glutaracidurie typ i -258 8.4.7 umgang mit komatösen patienten bei verdacht auf medikamente zur behandlung der beschriebenen stoffwechselstörungen -280 deutlich höheres aspirationsrisiko haben. hier muss über die karenzzeit in absprache mit dem anästhesisten individuell nach der grunderkrankung entschieden werden. nach einem trauma kommt es stressbedingt zu einer massiven verzögerung der darmmotilität. > somit ist zur beurteilung des aspirationsrisikos die zeit zwischen nahrungsaufnahme und unfallereignis und nicht zwischen unfall und operationsbeginn entscheidend. die geforderte karenzdauer ist im zusammenhang mit der dringlichkeit des eingriffs zu sehen und wird individuell und interdisziplinär festgelegt. neugeborene und säuglinge unter 6 monaten ohne iv-zugang sollten, wenn organisatorisch möglich, gezielt 4 h präoperativ nochmals gefüttert werden. auf diese weise wird die karenzzeit so kurz wie möglich gehalten, die gefahr einer präoperativen hypoglykämie gesenkt und die patientenzufriedenheit gesteigert. gesunde kinder ab dem 6. monat schlafen nachts 10-12 h, ohne eine exsikkose oder hypoglykämie zu entwickeln, und gleichen ihr flüssigkeitsdefizit durch morgendliches trinken problemlos aus. daher ist ab diesem alter bei chirurgischen eingriffen mit minimalem bis mittlerem gewebetrauma ( kap. 8. 1.2) keine präoperative intravenöse flüssigkeitstherapie erforderlich. bei größeren eingriffen mit zu erwartenden höheren flüssigkeitsverlusten und metabolisch instabilen kindern ist jedoch eine optimale präoperative hydratation sinnvoll. kommt es zu verzögerungen des operationsprogramms von über 2-4 h, sollte bei neugeborenen und säuglingen rechtzeitig mit einer intravenösen flüssigkeitssubstitution begonnen werden. größeren kindern kann ca. 3 h präoperativ nochmals tee oder wasser angeboten werden. ansonsten ist bei routineeingriffen eine präoperative intravenöse flüssigkeitszufuhr nicht erforderlich. die präoperative hydratation vor größeren eingriffen kann mit altersadaptierten elektrolyt-fertiglösungen (1/3-, 2/3-bzw. vollelektrolyt-lösungen bei älteren kinder) entsprechend des grundbedarfes ( abschn. 4.1, 7.4) erfol gen. grunderkrankungen mit einem deutlich höheren aspirationsrisiko sind z. b. gastroösophagealer reflux (gör), magenentleerungsstörungen, herz-oder niereninsuffizienz, zentralnervensystem-(zns-) und muskelerkrankungen, gastroenteritis und adipositas permagna. die individuelle festlegung der karenzzeit sollte in rücksprache mit dem anästhesisten erfolgen.  bei kindern mit erhöhtem aspirationsrisiko, da hier die karenzzeit verlängert werden muss  bei kindern, die im zustand der dehydratation oder der metabolischen entgleisung zur operation kommen  bei eingriffen mit einem absehbaren hohen flüssigkeitsverlust um die intraoperative infusionsmenge zu berechnen, müssen folgende komponenten berücksichtigt werden: ▬ grundbedarf: diejenige menge an wasser und elektrolyten, die notwendig ist, um den täglichen grundbedarf zu decken. ▬ präoperatives defizit: summe aus dem flüssigkeitsdefizit durch präoperative nüchternheit und ggf. präoperativ bestehendem volumenmangel oder elektrolytverschiebungen. ▬ intraoperativer korrekturbedarf: extrazelluläre flüssigkeitsverluste durch evaporation über offene körperhöhlen, gewebstrauma, verschiebungen in den dritten raum und chirurgisch bedingte blutverluste. der grundbedarf ersetzt die »normalen« verluste und ist abhängig vom körpergewicht. er lässt sich nach dem in ⊡ tabelle 8.2 dargestellten schema berechnen. in abhängigkeit von der operationsdauer und invasivität des chirurgischen eingriffs kann man die eingriffe in 3 kategorien einteilen und danach einfacher das infusionsregime planen (⊡ tabelle 8.3). bei kurzen chirurgischen eingriffen mit geringem trauma kann bei gesunden kindern auf eine intraoperative flüssigkeitstherapie verzichtet werden. moderne narkoseverfahren erlauben es, dass die kinder durch nahrungskarenz bedingte defizite direkt postoperativ durch trinken problemlos selbst korrigieren. eingriffe ab 1-h-länge erfordern eine genaue kalkulation der flüssigkeitstherapie. je komplexer ein chirurgischer eingriff ist, desto häufiger ist er mit schnellen und ausgeprägten volumenverschiebungen assoziiert. kurzfristige änderungen im flüssigkeitsbedarf durch gewebstrauma, blutverluste und oberflächenexposition in koinzidenz mit anästhetikawirkungen, temperaturwechseln und flüssigkeitsverschiebungen innerhalb der kompartimente müssen adäquat ausgeglichen werden. anästhetika dämpfen reaktionen und reflexe des organismus zur aufrechterhaltung einer normalen homöostase und steigern den flüssigkeitsbedarf. sie senken den peripheren gefäßwiderstand durch vasodilatation, und es kommt so zu einer erhöhung der totalen vaskulären kapazität um bis zu 25%. da zum einen größere mengen hypotoner infusionslösungen rapide die serumosmolarität vermindern und unvorhersehbare flüssigkeits-und elektrolytverschiebungen verursachen und zum anderen intraoperative verluste hauptsächlich aus blut und interstitieller flüssigkeit bestehen, werden intraoperativ isotone infusionslösungen verwendet. dabei kommen sowohl kristalloide als auch kolloide zum einsatz (⊡ tabelle 8.4). kristalloide sind elektrolytlösungen (ringer-lösung, isotone kochsalzlösung) oder niedermolekulare kohlenhydratlösungen (g 5%), die frei durch kapillarmembranen diffundieren können. plasmaersatzmittel werden in künstliche [hydroxyethylstärke (hes), gela tine, dextran] und natürliche [humanalbumin, gefrorenes frischplasma (ffp)] kolloide unterschieden. ihre volumenwirksamkeit und verweildauer sind ab hängig von der molekülgröße, der dispersion der lösung, dem kolloidos motischen druck, der eigenviskosität, dem abbau und der ausscheidung. intraoperativ erfogt der volumenersatz in erster linie mit kristallinen lösungen. es konnte gezeigt werden, dass die gabe von isotoner kochsalzlösung zur therapie der hypotonie bei frühgeborenen genauso effektiv wie die ⊡ tabelle 8.4. zusammensetzung intraoperativ gebräuchlicher infusionslösungen isotone kochsalzlösung (nacl 0,9%ig) klinisch relevante flüssigkeitsverluste außerhalb der normalen exkretion (z. b. über drainagen, durch fieber oder postoperatives erbrechen) sollten substituiert werden. die innerhalb einer stunde im einfuhr-ausfuhr-protokoll dokumentierte negative flüssigkeitsbilanz wird dabei in der darauffolgenden stunde mit 0,9%iger nacl-lösung ersetzt. das zeitintervall richtet sich nach dem volumen des flüssigkeitsverlustes in relation zum patienten. eventuell muss auch ein ausgleich des elektrolytverlustes erfolgen. dieser kann abgeschätzt oder in der entsprechenden flüssigkeit bestimmt werden (⊡ tabelle 8.6; cave: mit der kaliumsubstitution erst nach der ersten miktion beginnen!). neben den sichtbaren flüssigkeitsverlusten muss beachtet werden, dass durch die gewebetraumatisierung flüssigkeit dem intravasalraum entzogen und im dritten kompartiment eingelagert wird. dieser volumenverlust durch volumenverschiebung taucht in der bilanz nicht auf und kann nur anhand von kreislauf-und laborparametern nachvollzogen und ausgeglichen werden. daher sollte postoperativ das klinische gesamtbild des patienten kritisch beobachtet werden. verschiedene chirurgische erkrankungen erfordern eine spezifische postoperative tpn. diese kann in abhängigkeit vom allgemeinzustand, von der abdominellen (menge und farbe des refluierenden mageninhalts, qualität der ⊡ tabelle 8.6. durchschnittlicher elektrolytgehalt verschiedener körperflüssigkeiten. (nach berry 1997; sitzmann 1986) stellt sich nach den beschriebenen intervallen keine peristaltik ein, so sollten sorgfältig etwaige komplikationen ausgeschlossen werden. wenn abzusehen ist, dass postoperativ über einen zeitraum von mehr als 3 tagen eine teil-oder vollparenterale ernährung erfolgen muss, sollten zusätzlich zu den kohlenhydraten proteine und lipide supplementiert werden ( kap. 7.2). die parenterale substitution von kohlenhydraten folgt den regel, die unter den bedingungen des postaggressionsstoffwechsels üblicherweise zu beachten sind ( kap. 8.1.4 ). nach der akutphase ( kap. 8. 1.4) kommt es in der phase des postagressionsstoffwechsels zu einer katabolen stoffwechsellage mit einer gesteigerten energiegewinnung aus proteinen und fetten. pädiatrische aminosäurelösungen sollten daher ab dem 1. postoperativen tag tpn gegeben werden. es wird mit 0,5-1 g/kg kg und tag begonnen und pro tag um 0,5-1 g/kg kg gesteigert, bis die altersentsprechende tagesmenge erreicht ist ( kap. 4.3) . parallel zur tpn durchgeführte minimale enterale nahrungszufuhr (bis zu 10 ml/kg kg und tag) oral oder über eine nasogastrische, nasoduodenale, nasojejunale sonde bzw. über eine jejuniostomie hat einen protektiven effekt. mit der substitution von fetten kann im rahmen der tpn am 1.-3. postoperativen tag mit 0,5-1 g/kg kg und tag begonnen werden. alle 1-2 tage wird um 0,5-1 g/kg kg und tag bis zum erreichen der altersentsprechenden tagesmenge, ggf. unter monitoring der altersentsprechenden triglyzeridkonzentration im serum gesteigert ( kap. 4.3, 7, 11) . nach postoperativen lipidinfusionen ist eine verschlechterte oxygenierung des patienten aufgrund einer schä digung der pulmonalen kapillaren mit nachfolgendem »acute respiratory distress syndrome« (ards) beobachtet worden. dieser effekt kann möglicherweise auf eine durch freie radikale induzierte schädigung des kapilla ren dothels zurückgeführt werden. daher sollte bei intensivpatienten (mit potenziell hohem radikalmetabolismus) bei der lipidzufuhr auf die einhaltung physiologischer lipid-plasma-spiegel geachtet werden. bei neonaten kann es postoperativ leichter als bei älteren patienten zu einer vermehrten flüssigkeitstranssudation in das interstitium mit der gefahr von verstärkten wundödemen und resultierend wund-und anastomoseninsuffizienzen kommen ( kap. 2). darum haben bei diesen patienten exakte flüssigkeitsbilanzierung und monitoring einen besonderen stellenwert. 8 8. 1.4 physiologie des postaggressionsstoffwechsels verschiedenartige belastungen und schwere schädigungen des organismus, wie stress, trauma, verbrennungen, sepsis und große operative eingriffe, werden über bestimmte regulationsmechanismen auf charakteristische weise beantwortet. dabei können die auslösenden ursachen unterschiedlicher natur sein; der reaktionsablauf und die umstellungen des stoffwechsels jedoch sind relativ einheitlich und führen zum bild des sog. postaggressionsstoffwechsels bzw. postaggressionssyndroms. eine wesentliche funktion des postaggressionsstoffwechsels war urzeitlich die bereitstellung von stoffwechselsubstraten in lebensbedrohlichen situationen, ohne dass exogen nahrung zugeführt werden musste (autarkie, »fit for fight«). durch eine in abhängigkeit von der schwere des traumas ausgelöste stressreaktion kommt es zu interindividuell unterschiedlichen veränderungen des vegetativums, des neuroendokrinums und der peripheren hormondrüsen. aufgrund der klinik und der hormonellen und metabolischen veränderungen mit wirkung auf den kohlenhydratstoffwechsel, die proteinhomöostase, den lipidstoffwechsel, den wasser-und elektrolythaushalt, die mediatorfreisetzung und die immunreaktion werden 3 phasen unterschieden: ▬ akutphase (aggressions-oder schockphase), ▬ postaggressionsphase (katabole phase), ▬ reparationsphase (anabole phase). die aggressions-oder schockphase dauert je nach schwere der schädigung und erfolg einer frühzeitigen behandlung bis zu 24 h an und wird initiiert durch neurale faktoren, schmerzen und humorale mediatoren aus dem verletzungsgebiet, z. b. bei verbrennungen, ausgedehnten knochen-und weichteilverletzungen (polytrauma), großen operationen mit hohen blutverlusten oder anderen lebensbedrohlichen erkrankungen. ziel dieser phase ist dabei das überleben durch vermehrte bereitstellung von substraten an lebens wichtige organe (zns, herz, muskulatur) zu ungunsten untergeordneter organe (darm, haut) zu gewährleisten und flüssigkeitsverluste möglichst gering zu halten. der organismus reagiert mit einem erhöhten sympathikotonus und einer massiven ausschüttung von katecho-laminen (adrenalin, noradrenalin, dopamin), kortisol, vasopressin (adh), glukagon, hgh (»human growth hormone«, wachstumshormon) und endorphinen. die insulin ausschüttung aus den pankreaszellen wird supprimiert und gleichzeitig die insulinwirkung an den zellen herabgesetzt. durch stimulation der glukoneogenese und glykogenolyse in der leber und muskulatur kommt es zu einem weiteren anstieg des bz-spiegels, und es entsteht ein sog. pseudo-oder stressdiabetes. außerdem werden durch lipolyse freie fettsäuren aus dem fettgewebe mobilisiert, die proteinsynthese gehemmt, der cori-zyklus aktiviert sowie die laktatund pyruvatproduktion gesteigert. im frühen kindesalter kann es besonders bei nichtausreichender leberperfusion und daraus resultierender unzureichender glukoneogenese nach erschöpfung der glykogenreserven zu bedrohlichen hypoglykämien kommen. die postaggressionsphase schließt sich der akutphase an und kann tage bis wochen anhalten. sie ist gekennzeichnet durch eine katabole stoffwechsellage, die sich in einem hypermetabolismus, verminderter glukoseverwertung, gestörter glukoseregulation und einer gesteigerten energiegewinnung aus proteinen und fetten zeigt. obwohl die veränderungen mit der schwere der erkrankung korrelieren, bildet sich kein einheitliches hormonmuster in dieser phase aus. die katecholaminspiegel fallen im vergleich zur akutphase wieder ab, während die kortisol-und glukagonspiegel weiter ansteigen. dies führt zu einer erhöhten intrazellulären lipolyse, hemmt den glykogenaufbau aus glukose und steigert die glukoneogenese v. a. aus glukoplastischen aminosäuren. die bz-werte sind im hyperglykämischen bereich. darunter ist die insulinsekretion zwar wieder stimulierbar, jedoch ist die insulinwirkung an den zellen abgeschwächt, bzw. es besteht eine insulinresistenz durch störungen der insulinrezeptoren. im vordergrund steht außerdem der ausgeprägte proteinkatabolismus mit negativer stickstoffbilanz. die proteinhydrolyse überwiegt die proteinneusynthese. als proteinpool der proteolyse dient in erster linie die quergestreifte muskulatur, aber auch die herz-und zwerchfellmuskulatur sowie die glatte muskulatur des gastrointestinaltrakts. trotzdem findet eine vermehrte neusynthese von »akut-phase-proteinen«, wie α 1 -antitrypsin, c-reaktives protein (crp), fibrinogen und haptoglobin, statt. andere transportproteine und enzyme, wie albumin, transferrin oder cholinesterase, fallen jedoch stetig ab. die reparationsphase ist durch eine anabole stoffwechsellage gekennzeichnet und kann sich über wochen bis monate hinziehen. der hypermetabolismus und die hormonelle stressantwort bilden sich allmählich zurück, und in erster linie werden proteine zur stärkung der immunabwehr und zur reparation von geschädigten geweben synthetisiert. bislang gibt es keine möglichkeiten, das postaggressionssyndrom kausal zu behandeln. in erster linie gilt es, die stressoren rasch zu beheben, die vitalfunktionen zu sichern und den flüssigkeits-, elektrolyt-und säure-basen-haushalt auszugleichen. im vordergrund steht eine senkung des stoffwechsels durch ausreichende analgosedierung und ggf. intubation und beatmung. eventuell kann eine medikamentöse dämpfung des erhöhten sympathikotonus notwendig sein. eine weitere therapiegrundlage ist die überwachung des energiestoffwechsels, um die effektivität der ernährung zu kontrollieren und zu optimieren sowie komplikationen aufzudecken. wichtig ist der langsame nahrungsaufbau mit einem phasenadaptierten konzept. hypo-und hyperglykämien sowie hypertriglyzeridämien müssen vermieden werden. hyperglykämien werden mit ggf. extrem hohen insulindosen behandelt. eine kohlenhydratzufuhr ist in der regel nicht sinnvoll. lediglich bei bz-spiegeln < 60 mg/dl werden 3-5 mg/kg kg und stunde glukose unter engmaschiger bz-kontrolle infundiert. in der postaggressionsphase müssen, um die proteolyse auszugleichen und eine positivierung der stickstoffbilanz zu erreichen, aminosäuren in ausreichender menge zugeführt werden. dabei wird über ein geeignetes und stoffwechselgerechtes verteilungsmuster für die einzelnen aminosäuren noch heftig diskutiert. obwohl wachstumshormon das potenteste mittel zur stimulation der proteinsynthese mit dem effekt einer verbesserten wundheilung, verringerten infektionsrate und entsprechender verkürzung der behandlungsdauer ist, zeigten studien bisher jedoch eine erhöhte mortalität nach behandlung mit r-hgh bei akuter katabolie, so dass sich dieser zunächst viel versprechende therapieansatz zur unterdrückung der eiweißkatabolie nicht durchsetzen wird. durch eine in abhängigkeit von der schwere des traumas ausgelöste stressreaktion kommt es zu interindividuell unterschiedlichen veränderungen des vegetativums, des neuroendokrinums und der peripheren hormondrüsen. aufgrund der klinik sowie der hormonellen und metabolischen veränderungen mit wirkung auf den kohlenhydratstoffwechsel, die proteinhomöostase, den lipidstoffwechsel, den wasser-und elektrolythaushalt, die mediatorfreisetzung und die immunreaktion werden 3 phasen unterschieden. ziel der ernährungstherapie ist die verminderung einer negativen stickstoffbilanz durch parenterale/enterale ernährung, um die katabolie zu begrenzen. (congdon et al. 1990 ). eine reversible frühgeborenenosteopenie sollte trotzdem immer vermieden werden, da sie mit typischen komplikationen verbunden ist. so wurde eine erhöhte inzidenz von frakturen und knochendeformitäten (dolichozephalie) bei frühgeborenenosteopenie beobachtet (koo et al. 1995; pohlandt 1994a) . ein zusammenhang mit der entwicklung der bei frühgeborenen überzufällig häufig beobachteten myopie (pohlandt 1994a,b) wird vermutet. ursache könnten die unphysiologisch weichen orbitaknochen bei einer osteopenie sein, die dem sich entwickelnden augapfel ein im vergleich zum mineralisierten knochen weiches gegenlager bieten. hierdurch kann die entwicklung eines geringfügig zu »langen« augapfels begünstigt werden, der zur kurzsichtigkeit führt. des weiteren sind bei osteopenischen frühgeborenen längere respiratortherapie und atemhilfe notwen dig. anhalt für den ca-/p-bedarf kann die intrauterine nährstoffzufuhr für den feten bei korrespondierendem gestationsalter geben (koo 1993; ziegler et al. 1976) . im 3. trimenon der schwangerschaft baut der wachsende fetus im durchschnitt täglich ca. 120-160 mg ca/kg kg und tag sowie 65-80 mg p/kg kg und tag in das wachsende skelett ein (greer 1989; ziegler et al. 1976 frühgeborenenformula (⊡ tabelle 8.8) oder supplementierte muttermilch (⊡ tabelle 8.9) haben zwar einen höheren ca-/p-gehalt als anfangsnahrung (⊡ tabelle 8.8), trotzdem bleibt die zufuhr unterhalb der intrauterinen versorgung (⊡ tabelle 8.10). kalzium hat eine resorptionsrate von ca. 50%, p von ca. 80% bei muttermilchernährung. wird eine mittlere wachstumsgeschwindigkeit angenommen, so kann (auf der grundlage der daten der intrauterinen zufuhr; greer u. mccormick 1988; ziegler et al. 1976 ) eine zufuhr von 240-320 mg ca/kg kg und tag sowie 130-160 mg p/kg kg und tag geschätzt werden. auch diese werte können wegen der großen intra-und interindividuellen schwankungen (35-80%) nur als grober anhalt dienen (ehrenkranz et al. 1985; liu et al. 1989) . bei formulaernährung ist die bioverfügbarkeit geringer. in der literatur sind vielfach niedrigere werte publiziert, die z. t. auf konsensuskonferenzen festgelegt wurden. hierbei ist zu bedenken, dass auch bei der oben angegebenen intrauterinen ca-/p-zufuhr ist ein mittelwert angegeben, der ein gleichmäßig geradliniges körperwachstum voraussetzt. die extrauterine entwicklung unterliegt jedoch stärkeren schwankungen als die intrauterine. solche hohen tagesschwankungen wurden durch messungen der tatsächlichen extrauterinen wachstumsgeschwindigkeit von reifen neugeborenen, kleinkindern und jugendlichen (bernardi et al. 2003; walli et al. 1980) neben dem absoluten ca-/p-gehalt wird die resorption durch die komposition der verabreichten nahrung beeinflusst (bronner et al. 1992; carnielli et al. 1996) . bei einer starken schwankungsbreite wird für klinische belange i. allg. von einer 50%igen enteralen ca-resorption und einer 80%igen p-resorption ausgegangen, auch wenn die aufnahme aus formulanahrung niedriger liegt. bei vlbw-frühgeborenen mit osteopenie oder/und frakturen (geburtsgewicht <1.500 g) wurden bei einer vitamin-d-zufuhr von 400 ie/tag bei enteraler ernährung (20 ie/kg kg und tag vitamin d bei parenteraler ernährung) physiologische 25-hydroxyvitamin-d-spiegel gemessen (kein unterschied zur altersgleichen kontrollgruppe ohne osteopenie oder/und frakturen; koo et al. 1989) . bei der in mitteleuropa üblichen supplementation von 1.000 ie vitamin d/tag bei frühgeborenen kann von einer überschießenden vitamin-d-zufuhr ausgegangen werden. daher ist die vitamin-d-versorgung nicht der limitierende faktor für die knochenmineralisation. kalzium und phosphat mineralisieren den knochen in einem festen verhältnis von 5:3 (apatit). ist die ca-zufuhr zu gering, so wird renal vermehrt p ausgeschieden und umgekehrt. kalzium-phosphat-imbalancen lassen sich bei der berücksichtigung des physiologischen bedarfes vermeiden. bei ausgeglichenem ca/p-verhältnis sollte eine feste mischung zur supplementation verwendet werden. je unreifer ein frühgeborenes, desto höher ist die gefahr der entwicklung einer klinisch relevanten osteopenie. aus praktischen gründen eignet sich das geburtsgewicht besser als das gestationsalter zur individuellen risikoabschätzung, da hier auch »small-forgestational-age-(sga-)frühgeborene« mit aufhohlwachstum der richtigen risikogruppe zugeordnet werden können. es empfiehlt sich 2 risikogruppen zu unterscheiden: 1. frühgeborene mit einem geburtsgewicht >1.500 g: hier bildet sich bei unkompliziertem nahrungsaufbau in der regel lediglich eine milde osteopenie. eine routinemäßige supplementation mit ca/p ist nicht erforderlich. der ca-/p-stoffwechsel dieser patientengruppe sollte bis zu einem geburtsgewicht von 1.800 g überwacht werden. 2. frühgeborene mit einem geburtsgewicht <1.500 g: sind gefährdet, regelmäßig eine frühgeborenenosteopenie zu entwickeln. diese gruppe sollte mit ca/p supplementiert werden. die entstehung einer frühgeborenenosteopenie kann durch eine individuell angepasste ca-/p-supplementation am sichersten verhindert werden (greer u. mccormick 1988; pohlandt 1994c; trotter u. pohlandt 2002) . hierbei muss die zufuhr dem tatsächlichen bedarf, der von tag zu tag mit der wachstumsgeschwindigkeit variiert, angepasst werden. so können auch eine überdosierung und deren folgen minimiert werden. um die vorteile der individuellen prophylaxe nicht durch nachteile der überwachung aufzuheben, ist eine wenig invasive kontrollmethode notwendig. des weiteren darf das supplementationsschema nicht kompliziert sein, um es im klinischen alltag sicher und ohne fehldosierungen anwenden zu können. zur abschätzung des aktuellen bedarfes kann die renale ca-/p-elimination genutzt werden (karlen et al. 1985) . im urin kann hierzu eine vielzahl von quotienten errechnet werden (koo 1993) . bei supplementation mit einer festen ca/p-relation reicht die bestimmung des ca/kreatinin-(crea-)quo tienten jedoch aus. er wirkt sich stabilisierend auf die ergebnisse der ca-urin-messung aus und bietet eine möglichkeit zur unkomplizierten indivi duellen steuerung (matos et al. 1997; pohlandt 1994c; sargent et al. 1993) . bei einer therapie mit diuretika kann die renale ca-ausscheidung erhöht sein (hufnagle et al. 1982) und einen falsch-hohen ca/crea-quotienten verursachen. die ap im plasma (erhöhung bei zunehmender aktivierung von osteoklasten bei niedriger ca-/p-zufuhr und mobilisation von ca/p aus den knochenspeichern) kann neben der knochendichtemessung als langzeitgröße zur beurteilung der knochenmineralisation herangezogen werden. eine isoenzymbestimmung der ap kann bei unklarem befund die genese der erhöhten ap-aktivität klären. nephrokalzinosen unter ca-supplementation sind beschrieben. sie scheinen aber unter überwachter supplementation ein seltenes ereignis zu sein (saarela et al. 1999) . bei individueller dosisanpassung der ca-/p-supplementation wurden nephrokalzinosen noch seltener beobachtet als bei gleichmäßiger supplementation (trotter u. pohlandt 2002) . eine besondere gefahr stellt die gleichzeitige therapie mit diuretika für die entwicklung einer nephrokalzinose dar (trotter u. pohlandt 2002) . des weiteren sind gastrointestinale symptome denkbar, wurden aber bei dem angegebenen vorgehen der individuellen ca-/p-supplementation nicht beobachtet. > die veränderung der nahrungszusammensetzung (z. b. bei ca-/p-supplementation) kann die resorption anderer nahrungsbestandteile verändern. der zusatz von ca und p zur enteralen/parenteralen nahrung führt zu einer erhöhung der osmolarität. bei neugeborenen ist die vitaminkonzentration im plasma abhängig ▬ von der ernährung der schwangeren (baker et al. 1975) , ▬ vom plazentaren transport und dem geburtszeitpunkt (tsang 1985 (greene u. smith 1993) , ▬ niedrige körperspeicher (baydas et al. 2002; orzalesi 1987; wu u. chou 2001) , ▬ die erhöhte wachstumsgeschwindigkeit. der gehalt an vitaminen in muttermilch ist an den bedarf von termingeborenen adaptiert und reicht an den geschätzten bedarf bzw. die gängigen empfehlungen von frühgeborenen nicht immer heran (tsang et al. 1993) . darum wird bei den besonders leichten frühgeborenen (<1.500 g geburtsgewicht) eine orale vitaminsupplementation empfohlen. es gibt jedoch keine einheitliche meinung über die dauer der oralen supplementation. ▬ wir beginnen mit der enteralen supplementation, wenn der nahrungsaufbau zu 50% abgeschlossen ist, und empfehlen die fortführung bis zum 3. lebensmonat. ▬ bei neugeborenen mit intrauteriner wachstumsretardierung (sga) empfehlen wir ebenfalls eine vitaminsupplementation bis zum 3. lebensmonat. ▬ zur supplementation empfehlen wir die verwendung einer multivitaminpräperation; ⊡ tabelle 8.11, 8.12) ▬ die supplementation von vitamin k sollte bei allen frühgeborenen <35 schwangerschaftswoche (ssw) und kranken reifgeborenen wegen der unklaren enteralen resorption bei den ersten beiden gaben als subkutane, intramuskuläre oder intravenöse gabe erfolgen (greer 1995 ▬ bei gesunden reifen neugeborenen bringt eine intramuskuläre gabe keine vorteile gegenüber einer oralen supplementation (baker et al. 1975 ). ▬ verabreichung von 1 mg vitamin k i.v. oder i.m. am 1., 7. und 28. lebenstag an alle kranke neugeborenen (hanawa 1992; sutor et al. 1990 ). ▬ verabreichung von 2 mg vitamin k p.o. bei gesunden termingeborenen. die dosis der intravenösen vitamin-k-prophylaxe ist gegenstand der diskussion. die vitamin-k-spiegel bei frühgeborenen nach einmaliger gabe am 1. le benstag (1 mg vitamin k i.m) waren höher als bei reifgeborenen (kumar et al. 2001) . vitamin d/rachitisprophylaxe. die vitamin-d-prophylaxe mit 500 ie vitamin d/tag p.o. ab dem 7. lebenstag scheint auch zur vorbeugung bei sehr unreifen frühgeborenen (<1.500 g) auszureichen (koo et al. 1989) . bei reifen neugeborenen reicht eine orale vitamin-d-prophylaxe von 200 ie/tag aus (gartner u. greer 2003) . ob eine mangelversorgung von vitamin e bei säuglingen (v. a. bei frühgeborenen) zur peroxidation der erythrozytenmembran durch o 2 -radikale (koo et al. 1989 ) führen und eine verstärkte hämolyse zur folge haben kann, wird diskutiert . der bedarf an vitamin e wird stark beeinflusst von der menge an mehrfach ungesättigten fettsäuren, da vitamin e deren peroxidation hemmt. die empfohlene ratio von α-tocopherol/»polyunsaturated fatty acids« (pufa) beträgt 0,7-1 bei frühgeborenen (gross 1993 eine orale spurenelementsupplementation wird nur bei einer nachgewiesenen mangelversorgung an einzelnen spurenelementen empfohlen. der bedarf an spurenelementen wird sowohl durch muttermilch als auch durch formulanahrung bei reifen und gesunden neugeborenen gedeckt, 8 trotz oft unterschiedlicher bioverfügbarkeiten in den verschiedenen produkten (kersting u. alexy 2000) . für frühgeborene stehen dazu keine ausreichenden daten zur verfügung. untersuchungen zur resorption von einzelnen spurenelementen, z. b. zn, berichten widersprüchliche aussagen zur deckung des bedarfes bei frühgeborenen (obladen et al. 1998; rodriguez-rodriguez et al. 2000; wauben et al. 1999) . eine generelle orale spurenelementsupplementation ist daher derzeit nicht wissenschaftlich zu untermauern. eine orale fluoridsupplementation wird derzeit kontrovers diskutiert. in den usa, aber auch in deutschland, wird die zusätzliche orale zufuhr aufgrund des fluoroserisikos und des geringen präventiven effektes auf die zähne vor dem zahndurchbruch kritisch betrachtet (burt 1999; newbrun 1999) . möglicherweise ist die lokale anwendung von fluorid effektiver und weniger von nebenwirkungen belastet. die ⊡ tabellen 8.13 und 8.14 fassen den gehalt der einzelnen spurenelemente in muttermilch und formula zusammen und geben zufuhrempfehlungen für früh-und neugeborene, reife neugeborene und kinder. die hyperkaliämie bei frühgeborenen kann unterschiedliche ursachen haben. eine spezialform im frühgeborenenalter ist die bislang in ihrer pathophysiologie nicht geklärte »nonoligurische hyperkaliämie« (fusch u. jochum 2004) . prophylaxe und therapie sind unabhängig von der genese gleich. serumkalium >6,0 mmol/l oder typische elektrokardiogramm-(ekg-)veränderungen bei niedrigeren kalium-(k-)spiegel und imbalanzen anderer elektrolyte. zu hohe zufuhr, niereninsuffizienz, energiemangel, (pseudo)hypoaldosteronismus, hämolyse, schwere infektion, gewebsuntergang. die genese der »nonoligurischen hyperkaliämie« des frühgeborenen ist unbekannt. adynamie, ileus, muskuläre schwäche, herzrhythmusstörungen (von vermehrten extrasystolen bis kammerflimmern). im ekg: zelt t, qrs-verlängerung, av-block. besondere vulnerabilität bei katecholamintherapie. bestimmung der plasmaelektrolyte, elektrokardiographie. der frühzeitige beginn der aminosäurezufuhr mit der (teil)parenteralen ernährung von frühgeborenen (ab geburt) mit 0,5-1 g/kg kg und tag führt zu einer erhöhung der renalen durchblutung und zu einer senkung von behandlungsbedürftigen hyperkaliämien bei frühgeborenen. beim beginn einer parenteraler ernährung bei patienten mit unbekannter anamnese vor einer kaliumsupplementation zunächst die erste miktion und die plasma-k-spiegel abwarten. erst bei unauffälliger urinausscheidung und/ oder k-spiegeln der infusion bedarfsgerecht k zusetzen. …therapie der frühgeborenenhyperkaliämie bei säuglingen oft funktionell (u. a. »luftschlucken«, motilitätsstörungen), gastroösophagealer reflux. seltener: nahrungsmittelintoleranz, gastritis/ulkus (helicobacter pylori), entzündliche darmerkrankungen, hepatobiliäre störungen, infektionen. ausführliche anamnese (ernährung, wachstum); genaues erfragen der symp tome (bes. beziehung zur nahrungsaufnahme). klinische untersuchung; möglichst auch beobachtung der geschilderten symptomatik. omeprazol (antra mups; oral, gastral oder enteral 1-2 mg/kg kg und tag in 1-2 ed). ausführliche symptom-und ernährungsanamnese (überfütterung?); perzentilen. begleitsymptome ( oben) erfragen. gründliche klinische untersuchung (u. a. hydratation, abdominelle u. orientierende rektale untersuchung). ohne verzögerung der somatischen (meist auch der motorischen und psychosozialen) entwicklung; das körpergewicht (kg; evtl. auch die körperlänge, kl) fällt unter die 3. perzentile (bzw. fällt mehr als 2 hauptperzentilen unter die genetische zielhöhe). störung der relation zwischen nahrungsaufnahme bzw. nährstoffabsorption und energieumsatz. weltweit mangelernährung im vordergrund; in industrieländern auch störungen der nahrungsabsorption (maldigestion, malabsorption) bedeutsam. die diskussion um die therapiebedürftige hypoglykämie ist kontrovers, insbesondere im hinblick auf postnatale normbereiche. beim unterschreiten von bz-schwellenwerten kann das risiko für kurzfristige oder auch langfristige störungen im zusammenhang mit diesem substratmangel erhöht sein (literaturangaben zur diskussion unten). hypoglykämie: postnatal bz <1,7-2,0 mmol/l bzw. 30-35 mg/dl (erste lebensstunden); danach bz unter 2,2-2,6 mmol/l bzw. 40-47 mg/dl. physiologisch: nach geburt bz-abnahme (neugeborene) bis auf ca. 2,5-2,8 mmol/l (45-50 mg/dl); dann stoffwechselanpassung (u. a. glykogenabbau, gluconeogenese). oft asymptomatisch bzw. unspezifisch (u. a. apathie, hypotonie, trinkfaulheit; hypothermie; bradykardie, tachykardie; apnoen), auch neurologische symptome (z. b. hyperexzitabilität, konvulsionen). erschöpfte glykogenvorräte (u. a. hypotrophie, frühgeborene, asphyxie, anpassungsstörung); fetaler hyperinsulinismus (u. a. mütterlicher diabetes, schwere rhesusunverträglichkeit, wiedemann-beckwith-syndrom, nesidioblastose); metabolische/hormonelle erkrankungen [u. a. nebennierenrinden-(nnr-)insuffizienz, mangel an somatotropem hormon (sth), blutaustausch, sepsis, galaktosämie), polyglobulie. ▬ hypothyreose, ▬ adrenogenitales syndrom (ags), ▬ biotinidasemangel, ▬ galaktosämie, ▬ phenylketonurie (pku), ▬ ahornsirupkrankheit, ▬ medium-chain-acyl-coa-dehydrogenase-(mcad-)mangel, ▬ long-chain-3-oh-acyl-coa-dehydrogenase-(lchad-)mangel, ▬ very-long-chain acyl-coa-dehydrogenase-(vlcad-)mangel, ▬ carnitin-palmitoyl-transferase-(cpt-)1-mangel, ▬ carnitin-palmitoyl-transferase-(cpt-)2-mangel, ▬ carnitin-acylcarnitin-translokase-mangel, ▬ glutaracidurie typ 1, ▬ isovalerianacidämie. biotin wird an eiweiß gebunden mit der nahrung aufgenommen. das sub strat der biotinidase ist eine biotin-lysin-verbindung (biocytin). propionyl-coa-carboxylase (im abbauweg von isoleucin, methionin, threonin und valin), 3-methylcrotonyl-coa-carboxylase (im leucinstoffwechsel), pyruvatcarboxylase (glukoneogenese) und der acetyl-coa-carboxylase (fettsäurenstoffwechsel) benötigen biotin als koenzym (wolf 2001; wolf et al. 1985; sweetman u. nyhan 1986) . da neugeborene über ein gewisses depot an biotin verfügen, treten mangelerscheinungen in der regel erst im späten säuglings-oder kleinkindesalter (late-onset-form) auf. sämtliche klinischen symptome bilden sich als folge der zu niedrigen aktivierung der 4 biotinsensiblen enzyme aus. sie werden aber offensichtlich erst manifest, wenn die biotinidaseakti vität unter 10% der altersentsprechenden norm liegt (moslinger et al. 2003; wolf 2001) . der autosomal-rezessiv vererbte defekt betrifft sowohl die zytoplasmatische als auch die mitochondriale biotinidase. das gen ist auf dem chromosom 3p25 lokalisiert (moslinger et al. 2003; cole et al. 1994) . eine pränatale erfassung ist möglich. das klinische bild des biotinidasemangels ist gekennzeichnet durch erythematöses, schuppiges, manchmal auch nässendes exanthem oder seborrhö, gelegentlich alopezie, acidose (laktatacidose), erbrechen, dehydratation, tachypnoe und/oder stridor (moslinger et al. 2003; wolf 2001; cole et al. 1994) , gelegentlich findet man leukopenie oder monozytopenie sowie eine störung der t-lymphozytenfunktion (cowan et al. 1979 durch mangel an biotin stauen sich die substrate vor den biotinsensiblen carboxylasen. im blut sind laktat, pyruvat und propionat vermehrt; im urin kann man hohe konzentrationen von 3-hydroxypropionat, methylzitrat, 3-hydroxy-isovaleriansäure, 3-methylcrotonylglycin und tiglylglycin sowie von laktat und pyruvat messen (sweetman 1991) . die mithilfe der gaschromatographie-massenspektrometrie (gc-ms) detektierbaren metabolitenmuster sind bei biotinidasemangel (⊡ tabelle 8.15) identisch mit dem des holocarboxylasedefektes, nur etwas geringer (sweetman 1991) : biotinidaseaktivität ist in serum, leukozyten und fibroblasten bestimmbar. ein einfacher farbtest findet als screeningmethode aus getrocknetem blut (guthrie-karte) anwendung. …therapie die behandlung des biotinidasedefekts besteht in der substitution 5-40 mg biotin/tag (freies biotin!) oral (wallace 1985; baumgartner et al. 1985) . liegt die biotinidaseaktivität unter 15-18% der altersnorm, sollte therapiert werden. als therapiekontrolle sollte biotin im serum (oder biocytin im urin) gemessen werden: zunächst alle 3-6 monate, später einmal im jahr. bei schweren formen sollten 1-mal jährlich eine hörprüfung, augenhintergrund-und visusuntersuchung vorgenommen werden, ggf. auch elektroenzephalographie (eeg) und ct bzw. magnetresonanztomographie (mrt) des schädels. galaktosämie, galaktose-1-phosphat-uridyltransferase-mangel, klassischer galaktosämie-transferase-defekt, galaktosämie typ i, »galactosemia«, »galactosaemia«, »gal-1-put deficiency«. bei der (klassischen) galaktosämie handelt es sich um die häufigste angeborene störung im kohlenhydratstoffwechsel. galaktose, bestandteil des milchzuckers, kann nicht adäquat abgebaut werden. schon mit der ersten muttermilch erhält ein neugeborenes größere mengen an galaktose. daraus entstehen galaktose-1-phosphat und der alkohol galaktitol, die zu den klinischen symptomen führen (holton et al. 2001) . schwere und leichte verlaufsformen sind zu beobachten. der auch in den erythrozyten nachweisbare galaktose-1-phosphat-uridyltransferase-defekt wird autosomal-rezessiv vererbt. heterozygote sind klinisch gesund. bei ihnen bildet sich im erwachsenenalter allerdings häufiger als bei gesunden ein grauer star (katarakt) aus. das gen der galaktose-1-phosphat-uridyltransferase liegt auf dem chromosom 9 (9p13). mehr als 150 mutationen sind weltweit bekannt; hierbei weisen die galaktosämiepatienten in europa zu 70-80% nur 2 mutationen auf (elsas u. lai 1998) . die schwere der klinischen symptome korreliert mit den spezifischen mutationen. unter den milderen formen findet sich weltweit die duarte-variante (duarte 1 und 2) mit reduktion der enzymaktivität auf ca. 50% der norm (item et al. 2002) . die häufigkeit der galaktosämie (schwere form) liegt zwischen 1:40.000 bis 1:70.000. die milderen mutationen sind häufiger, und ihre frequenz wird auf 1:3.000bis 1:4.000 geschätzt (gitzelmann 2000) . die großen mengen an galaktose, die mit der muttermilch aufgenommen werden, können aufgrund des stoffwechselblocks nur noch phosphoryliert werden; das anfallende galaktose-1-phosphat hemmt sowohl die glykolyse als auch die glukoneogenese. hypoglykämien sind die folge. der sich ebenfalls bildende alkohol galaktitol führt zunächst zur aufquellung der augenlinsen (reversibel), nach ca. 14 tagen jedoch zu bleibenden strukturveränderungen mit der folge der ausbildung eines grauen stars. schon in den ersten lebenstagen, nach dem trinken von muttermilch oder einer milchzuckerhaltigen säuglingsnahrung, kommt es zu klinischen symptomen, wie trinkunlust, unterzuckerungen (hypoglykämien) und/oder gelbsucht (ikterus, mit einem großen anteil von konjugiertem/direktem bilirubin) als zeichen einer leberfunktionsstörung, und es trüben sich die augenlinsen (grauer star/katarakt). die stoffwechselveränderungen können im neugeborenenalter auch zu bewusstseinsverlust und krämpfen und sogar zum tod führen (hirnödem). aus bisher ungeklärten gründen erleiden galaktosämiepatienten in den ersten lebenstagen häufiger eine sepsis mit escherichia coli (coli-sepsis; levy et al. 1977) . neben den akuten veränderungen im neugeborenenalter finden sich weitere typische symptome bei kindern und jugendlichen: allgemeine entwicklungsverzögerung, sprachentwicklungsstörungen, intelligenzminderugen (bei mädchen bis zu einem iq-verlust von 20%, bei jungen etwas weniger) und bei mädchen eine ovarialinsuffizienz (unterfunktion der eierstöcke) auch bei guter diätführung, gelegentlich chronischer leberschaden (leber zirrhose) und/oder niereninsuffizienz (mit fanconi-syndrom; holton et al. 2001; schweitzer et al. 1993; waggoner et al. 1990 ). die ursachen der in telligenzminderungen und der ovarialinsuffizienzen sind bisher ungeklärt. die galaktosämie ist als krankheit schon fast 70 jahre bekannt, und seit dieser zeit existieren auch überlegungen und maßnahmen zu ihrer behandlung. die klinischen symptome sind relativ unspezifisch (hyperbilirubinämie, hypoglykämie), und es gibt eine große zahl anderer erkrankungen, die differenzialdiagnostisch infrage kommen. die neugeborenen werden häufig klinisch auffällig, bevor die ergebnisse des neugeborenenscreeningtests ( unten) vorliegen. ein einfacher test zum nachweis von galaktose im urin (z. b. reduktionsproben nach fehling oder benedict; clinitest-tbl.) kann entscheidend sein. glukose im blut ist bei der ergebnisinterpretation vorsicht geboten. sowohl galaktose als auch bilirubin reagieren in diesem test (newman et al. 2002 galaktosevermehrungen im blut sind beobachtet worden auch bei: ▬ reifungsstörungen eines der im beutler-test beteiligten enzyme bzw. der leber allgemein (ono et al. 2000) , sowie bei ▬ fehlbildungen der pfortader, ▬ portovenösen und portoarteriösen shunts oder bei ▬ persistierendem ductus arantii (gitzelmann et al. 1992; ono et al. 1998 ). hinsichtlich der allgemein klinischen symptome der galaktosämie im neugeborenenalter ist differenzialdiagnostisch an folgende störungen zu den ken: ▬ sepsis, ▬ angeborene organoacidurien (z. b. propionacidurie), ▬ mitochondriopathien, ▬ neonatale hämochromatose, ▬ α 1 -antitrypsinmangel, ▬ tyrosinose typ i u. a. galaktose ist in allen milchsorten (als laktose) und in pflanzen (als freie galaktose) oder in form von normalerweise nichtspaltbaren sacchariden vorhanden. in komplexen kohlenhydraten existieren 2 unterschiedliche chemische bindungsarten von galaktose, die α-galaktosidische (z. b. auch in raffinose oder stachyose) und die β-galaktosidische bindung. der menschliche organismus kann nur β-galaktosidische bindungen spalten. in tierischen geweben lässt sich galaktose nur in spuren nachweisen. galaktose-1-phosphat, das sich vor dem stoffwechselblock bei der klassischen galaktosämie anstaut, hemmt z. b. glukose-6-phosphatase, glukose-6-phosphat-dehydrogenase, phosphoglukomutase, glykogenphosphorylase. sowohl die bereitstellung von glukose durch glykogenabbau und auch die synthese von glukose in der leber (glukoneogenese) sind beeinträchtigt (gitzelmann 1995) . hypoglykämien sind die folge. galaktitol wird schon in der fetalzeit gebildet und ist im fruchtwasser sowie im nabelschnurblut, später auch im urin, nachweisbar. seine menge korreliert mit der des galaktose-1-phosphats in den erythrozyten, jedoch nicht mit der galaktosekonzentration im blut (jakobs et al. 1995; palmieri et al. 1999; ⊡ tabellen 8.16 und 8.17) . heterozygote und gemischtheterozygote haben leicht erhöhte galaktitolkonzentrationen sowohl im blut als auch im urin (jakobs et al. 1995 die defekte der phenylalaninhydroxylase sind angeboren. das gen liegt auf dem chromosom 12 (q21-q24.1). über 400 mutationen des phenylalaninhydroxylasegens sind bisher beschrieben (podskarbi 2001; scriver u. kaufman 2001) . schwere und leichte pku-formen weisen spezifische mutationen auf. spontanmutationen sind bisher nicht bekannt. die häufigkeit der klassischen pku liegt in deutschland bei etwa 1:10 000, mildere formen (hyperphenylalaninämien) sind etwa gleich häufig/selten. damit ist etwa jeder 50ste überträger der pku! basierend auf klinischen erfahrungen werden folgende untergruppierungen vorgenommen (mönch u. link 2002; scriver u. kaufman 2001) : ▬ klassische pku: phenylalaninkonzentrationen bei freier kost über 20 mg/ dl (>1.205 µmol/l), phenylalanintoleranz unter 400 mg/tag; ▬ milde pku: phenylalaninkonzentrationen bei freier kost zwischen 10 mg/ dl und 20 mg/dl (zwischen 602 µmol/l und 1.205 µmol/l), phenyl alanintoleranz zwischen 400 mg/tag und 600 mg/tag; ▬ hyperphenylalaninämie: phenylalaninkonzentrationen bei freier kost stets unter 10 mg/dl (>603 µmol/l). eine weitere gruppe bilden die ▬ tetrahydrobiopterin-(bh4-)sensiblen phenylalaninhydroxylasedefekte mit maximaler phenylalaninblutkonzentration in der regel nicht über 20 mg/dl (1.205 µmol/l). nach bisherigen erfahrungen sind mehr als ein drittel der hyperphenylalaninämien und milden pkus tetrahydrobiopterinsensibel (kure et al. 1999; muntau et al. 2002) . folge der verminderten hydroxylierung von phenylalanin ist ein mangel an tyrosin. dieser führt zu ungenügender synthese von nervenüberträgerstoffen (dopamin), von melanin (haut-, haar-und augenfarbstoff), von catecholaminen (gewebshormonen; adrenalin, noradrenalin), nicht jedoch von thyroxin. der schwere hirnschaden durch hohe phenylalaninkonzentrationen ist das resultat der summation mehrerer ungünstiger faktoren (scriver u. kauf man 2001) . phenylalanin wird bei sehr hohen spiegeln zu phenylbrenz trau bensäure (phenylpyruvat), phenylmilchsäure (phenyllaktat), phenyl essigsäure (phenylacetat), u. a. abgebaut. sowohl hohes phenylalanin als auch z. b. phenylbrenztraubensäure blockieren den aufbau von gehirnsubstanz (myelin), den energiestoffwechsel der hirnzellen und die synthese von nervenüberträgerstoffen. außerdem wird das transportsystem der neutralen aminosäuren durch phenylalanin so überlastet, dass es zu einem mangel besonders von tyrosin und tryptophan in den hirnzellen und damit der neurotransmitter dopamin und serotonin kommt (dyer et al. 1996; hommes 1989) . daraus resultieren einschränkungen der hirn entwicklung und -funktion (besonders von kognitiven leistungen; lou et al. 1985) . das gehirn benötigt aber in jedem lebensalter für seine optimale funktion eine ausreichende menge an neurotransmittern! patienten mit unbehandelter klassischer pku fallen frühestens im 3.-4. monat durch verzögerung der statomotorischen entwicklung auf. schon zu dieser zeit kann der typische geruch auftreten. in den späteren jahren werden die mangelhafte gehirnentwicklung, mikrozephalie, geistige, psychosoziale und statomotorische retardierung, helle haut und blonde haare deutlich (scriver u. kaufman 2001) . hyperphenylalaninämien können milder ausfallen und/oder später auftreten. die auch zu den anzustrebenden und permanent einzuhaltenden phenylalaninkonzentrationen gibt es aps-empfehlungen(1997; ⊡ tabelle 8.23). einmal jährlich sollten umfangreiche klinisch-chemische untersu chungen zur kontrolle der optimalen versorgung mit allen nährstoffen erfolgen. …therapie frauen mit pku sollten schwangerschaften möglichst planen und mit einer strengen diät schon vor der konzeption beginnen. die behandlung der pku ist aus der kinder-und jugendzeit bekannt und mit dieser nahezu identisch. der zu erwartende altersabhängige bedarf an phenylalanin und tyrosin, der allerdings individuell erheblich abweichen kann, ist in ⊡ tabelle 8.24 angegeben (elsas u. acosta 1999; rohr et al. 1987) . für die substitution von aminosäuren zur deckung des proteinbedarfes unter gleichzeitiger berücksichtigung der speziellen ernährungbedürfnisse von schwangeren stehen präparate der firmen shs/heilbronn (p-am ma ter nal) und milupa/friedrichsdorf (pku 3) zur verfügung (mönch u. link 2002) . die betreuung der schwangeren sollte nach dem in ⊡ tabelle 8.25 vorgegebenen schema erfolgen (aps1997). die ahornsirupkrankheit ist eine autososmal-rezessiv vererbte störung im abbau (oxidative decarboxylierung) der 3 verzweigtkettigen aminosäuren (chuang u. shih 2001; menkes et al. 1954; mönch u. link 2002; scriver et al. 1985) . sie wird im neugeborenenscreening mit der tandem-ms durch messung der verzweigtkettigen aminosäuren mit einer häufigkeit zwischen 1:55.000 bis 1:300.000 erfasst. klinisch auffällig werden die patienten mit klassischer, schwerer form der ahornsirupkrankheit schon in den ersten lebenstagen. sonderformen (intermittierend, intermediär oder thiaminsensibel) manifestieren sich im säuglings-und kindesalter. hyperammonämien treten bei der ahornsirupkrankheit in der regel nicht auf. schon im neugeborenenscreening mit der tandem-ms lassen sich in den ersten lebensstunden die vermehrungen der verzweigtkettigen aminosäuren absolut und relativ zu anderen aminosäuren (z. b. methionin und phe nylalanin) nachweisen. leucin, isoleucin und auch alloisoleucin lassen sich aber mit dieser methode nicht voneinander unterscheiden und werden als summe gemessen, xle). der ziel der langzeitbehandlung (mönch u. link 2002) ist es, katabole stoffwechselsituationen unter allen umständen zu vermeiden, die blutkonzentrationen der verzweigtkettigen aminosäuren im normwertbereich zu halten und die bildung der verzweigtkettigen ketosäuren zu minimieren. da alle 3 verzweigtkettigen aminosäuren essenziell sind und leider nicht in gleicher konzentration in den natürlichen lebensmitteln vorkommen, gestaltet sich die bedarfsdeckung im rahmen der diätetischen behandlung gelegentlich schwierig. richtschnur bei der diätetischen behandlung ist die deckung des bedarfes an leucin durch natürliche lebensmittel (z. b. milch). die plasma-leucin-konzentration sollte 300 µmol/l (4 mg/dl) nicht überschreiten. der bedarf an verzweigtkettigen aminosäuren ist etwa gleich, der leucingehalt in nahrungsmittelproteinen aber fast doppelt so hoch wie der von isoleucin und valin. aus diesem grund müssen häufig nach erreichen der maximal tolerierten menge an leucin isoleucin und valin als kristalline monoaminosäuren separat verabreicht werden (⊡ tabelle 8.28). der gesamteiweißbedarf wird mit hilfe eines leucin-, isoleucin-und valinfreien aminosäurengemisches gedeckt. auf eine ausreichende zufuhr an kalorien und die deckung des bedarfes an vitaminen, essenziellen fettsäuren, mineralien und spurenelementen muss geachtet werden. je nach compliance sollten die konzentrationen der verzweigkettigen aminosäuren im blut bei den patienten alle 2-6 wochen kontrolliert werden. trotz frühzeitiger entdeckung und optimaler diättherapie entwickeln sich die patienten in der regel nicht altersentsprechend; meist zeigen sie verzögerungen der statomotorischen und der intelligenzentwicklung (hilliges et al. 1993) . die therapie muss lebenslang durchgeführt werden! mittelketten-coa-dehydrogenase-defekt synonyme mcad-mangel, »deficiency of medium-chain acyl-coa dehydrogenase«, »mcad deficiency«, »acadm deficiency«. bei dem mcad-defekt handelt es sich um die häufigste angeborene, auto somal-rezessiv vererbte störung im abbau (β-oxidation) der fettsäuren. klinisch auffällig werden die betroffenen in der regel in situationen mit stoffwechselstress, d. h. in der katabolie. dann findet man auch große mengen der mittelkettigen fettsäuren und deren derivate im blut und im urin. energiemangelzustände charakterisieren das klinische bild (divry et al. 1983) . in deutschland wird jetzt bei allen neugeborenen im rahmen des erweiterten neugeborenenscreenings auf mcad-defekte untersucht. die häufigkeit liegt in mitteleuropa bei etwa 1:10.000. (roe u. ding 2001; stanley 2000) . das gen der mcad ist auf dem chromosom 1 (1q31) lokalisiert (andresen et al. 1997 ). typischerweise treten die hypoketotischen hypoglykämien (bei patienten mit mcad-defekt ohne screening) zwischen dem 6. und 24. lebensmonat erstmals auf; etwa 25% der betroffenen versterben in der ersten attacke (wilcken et al. 1994) . ausgelöst werden diese zustände meist durch fieber bei banalen infekten (erhöhter energiebedarf), erbrechen, durchfall (mangelnde kohlenhydratzufuhr) oder zu lange fastenphasen (mehr als 6-10 h bei einem säugling). die typischen symptome sind: ▬ hypoglykämie, ▬ hypoketonämie/-urie (keine ketonkörperbildung), ▬ muskelschlaffheit, ▬ somnolenz, koma, ▬ krampfanfälle, ▬ herzstillstand. das klinische bild kann blitzartig auftreten, so dass die diagnose eines »sudden infant death syndrome« (sids) gestellt wird (iafolla et al. 1994; roe u. ding 2001; stanley 2000; wilcken et al. 1994) . bei ausgeglichener stoffwechsellage (intervall) sind in der regel keine symptome feststellbar. aus öfteren leichteren stoffwechselentgleisungen können statomotorische entwicklungsrückstände, nach schweren hypoglykämien auch zerebralschäden und/oder krampfleiden resultieren (roe u. ding 2001; stanley 2000; wilcken et al. 1994 die unter punkt 1, 2, 3, 4, 7 und 9 angeborenen störungen werden auch im erweiterten neugeborenenscreening erfasst. die differenzialdiagnostische klärung bringt in der regel die tandemma ssenspektrometrische analyse der acylcarnitine im blut sowie die gc-ms-trennung der organischen säuren im urin. vor allem in episoden von stoffwechselstress fallen vor dem defekt große mengen an octanoat (c8), hexanoat (c6) und decanoat (c10) an. der organismus nutzt alle alternativen metabolischen möglichkeiten, diese substrate abzubauen. zunächst werden carnitinester gebildet: hexanoylcarnitin, octanoylcarnitin, decanoylcarnitin und decenoylcarnitin (10:1). über mikrosomale und peroxisomale stoffwechselwege (z. b. omegaund omega-1-oxidationen), bindungen an glycin u. a. entstehen für diese krankheit typische metabolite, die man im urin nachweisen kann: adipinsäure, suberinsäure, sebacinsäure, suberylglycin, 5-oh-hexanoat und 7-oh-octanoat. diese ausscheidungsmuster haben v. a. differenzialdiagnostische bedeutung. beim neugeborenenscreening mit der tandem-ms findet man die oben genannten carnitinester im blut vermehrt und dazu die zu berechnenden relationen von c6/c2, c8/c2, c8/c10, c8/c12 pathologisch, freies carnitin (c0) ist nicht immer erniedrigt, aber alle fettsäurenmetaboliten länger als c12 liegen im normbereich (carpenter et al. 2001; lehotay et al. 2004; pourfarzam et al. 2001) . die im stoffwechselstress auftretenden hypoglykämien sind im wesentlichen die folge der aufgebrauchten kohlenhydratspeicher (glykogen), aber auch auf eine verarmung des körpers an freiem acetoacetat zurückzuführen. acetoacetatmangel wirkt u. a. hemmend auf den pyruvatdehydrogenasekomplex. schließlich führen hohe konzentrationen von octanoat zur zerstörungen von mitochondrien in den gehirnzellen (hirnödem; roe u. ding 2001). bei säuglingen und kleinkindern kommt es durch stoffwechselentgleisungen zu einem deutlichen abfall der konzentration des carnitins im blut. im intervall findet man allenfalls etwas erhöhte acylcarnitine im blut. die schon erwähnte substratunspezifität der dehydrogenasen ermöglicht einen geringen fettsäurenabbau. vielleicht ist dies auch der grund dafür, dass einige patienten nie klinische symptome ausbilden. ist das tandem-ms-ergebnis nicht eindeutig genug, besteht die möglichkeit, einen mcad-mangel durch einen phenylpropionatbelastungstest zu erfassen (20-25 mg/kg kg). phenylpropionat wird bei gesunden von der mcad zu hippurat abgebaut. bei einem mangel werden große mengen der verabreichten substanz (als glycinkonjugat) unverändert wieder mit dem urin ausgeschieden (stanley 2000) . zur erkennung von heterozygoten stehen die möglichkeiten der genetischen analyse im vordergrund. bei dem mcad-defekt wurden weltweit relativ wenige mutationen gefunden. (in mitteleuropa haben über 90% der betroffenen die gleiche mutation (k304e [g985a]); wang u. khoury 2000). …therapie > das prinzip der akutbehandlung besteht in der normalisierung der blutzuckerwerte durch eine glukoseinfusion. in den ersten 24 h ist die infusion von mindestens 10 g/kg kg glukose mit elektrolyten (wenn notwendig auch in kombination mit der natriumbikarbonatgabe) notwendig. falls der mcad-defekt gesichert ist, sollte zusätzlich l-carnitin (z. b. 100 mg/kg kg und tag) oral oder parenteral verabreicht werden. die normale orale ernährung muss nicht unterbrochen werden und sollte nach normalisierung der glukoseblutkonzentrationen mit maltodextrin angereichert werden. bei der langzeitbehandlung muss v. a. darauf geachtet werden, dass die betroffenen nicht länger als 6-8 h ohne nahrung bleiben (vermeidung von hungerzuständen). bei der zusammenstellung der nahrung sollte der fettanteil reduziert und dafür derjenige der kohlenhydrate erhöht werden. eine carnitinsubstitution ist zu empfehlen (z. b. 50 mg/kg kg und tag). bei fieberhaften infekten sollte gleich maltodextrin oral zusätzlich gegeben und die zeit zwischen den einzelnen mahlzeiten verkürzt werden (⊡ tabelle 8.29). die blutglukose-, acylcarnitin-und carnitinkonzentrationen sollten im ersten lebensjahr ca. 1-mal im monat, im zweiten lebensjahr etwa alle 4 wochen und danach alle 3 monate aus sicherheitsgründen kontrolliert werden. eine individuelle diätetische beratung ist in der regel erforderlich, um die nahrungsmittel entsprechend den lebensgewohnheiten der patienten auszuwählen und zusammenzustellen (z. b. gabe von ungekochter stärke bei langen schlafphasen). bei der glutaracidurie typ i handelt es sich um einen autosomal-rezessiv vererbten defekt der mitochondrialen glutaryl-coa-dehydrogenase, ein enzym im stoffwechsel von lysin, oh-lysin und tryptophan (goodman u. frerman 1995 , goodman et al. 1975 die typischen morphologischen veränderungen (z. b. makrozephalie) kann man bereits bei neugeborenen feststellen. im säuglingsalter treten die neurologischen (extrapyramidalen) symptome auf. in den ersten 2 lebensjahren bildet sich dann das komplette klinische bild aus mit choreoathetotischen, hyperkinetischen/dyskinetischen bewegungsabläufen, rumpfbetonter hypotonie, dysarthrie, dysphagie, verlust der kopfkontrolle, opisthotonus und schwerer geistiger retardierung, aber auch hyperhidrose sowie schlafstörung. stoffwechselentgleisungen führen zu erbrechen, rhabdomyolyse, krampf anfällen und koma. bei untersuchungen des gehirns findet man subdurale hämatome, pseudozysten und mangelnde myelinisierung (cave: fehldiagnose »kindsmisshandlung«!; haworth et al. 1991; hoffmann u. zschocke 1999; kyllerman et al. 1994; muntau et al. 1977) . verluste der weißen hirnsubstanz (frontotemporale atrophie; hochpathologische eeg-veränderungen) und des hypothalamus, mit im ct oder mrt darstellbaren weiten sulci und vergrößerten seitenventrikeln, schreiten besonders während metabolischen entgleisungen fort. häufig versterben die kinder schon vor erreichen des 10. lebensjahres in zuständen mit hyperthermie oder im bild eines reye-syndrom z. b. anlässlich eines viralen infekts (hoffmann et al. 1995) . bis zu 10% der personen mit glutaryl-coa-dehydrogenase-mangel bilden keine klinischen symptome aus; milde formen fallen durch motorisch bedingte artikulationsstörungen auf, bei einigen betroffenen besteht eine riboflavinsensitivität (100-400 mg/tag). eine pränatale diagnostik ist möglich (busquets et al. 1998 (wendel et al. 1995) . klinisch ist die glutaracidurie vom leigh-syndrom abzugrenzen. glutarsäure staut sich vor dem enzymblock. weitere daraus entstehende metaboliten sind oh-glutarsäure, glutaconsäure, glutarylcarnitin u. a.. wie glutarsäure sind auch glutaconsäure und 3-oh-glutarsäure hirntoxisch. als eine der folgen ist die gaba-konzentrationen besonders im nucleus caudatus und im putamen erniedrigt (hoffmann u. zschocke 1999) . in ⊡ tabelle 8.30 sind die urinkonzentrationen der typischen metaboliten, deren konzentrationen aber inkonstant und nahrungsabhängig sind, zusammengefasst (sweetman 1991) . beim neugeborenenscreening mit der tandem-massenspektrometrie (tandem-ms) wird als marker glutarylcarnitin im getrocknetem blut gemessen (hoffmann et al. 1996 zur beschleunigung der ausscheidung der toxischen substanzen sollte die diurese mit furosemid (lasix; 1-2 mg oral oder 0,5-1 mg/kg kg i.v., alle 6-12 h) forciert werden. nach spätestens 3 tagen proteinkarenz muss mit der gabe von zunächst 0,5 g/kg kg und 24 h natürlichem eiweiß begonnen und in den darauf folgenden tagen auf bis zu 1 g/kg kg und 24 h ggf. unter zusätzlicher gabe von 0,5 g aminosäurenmischung gesteigert werden. einen spezifischen kontrollparameter gibt es nicht. das klinische bild muss entscheiden. laborkontrollen: ▬ blutgase, ▬ konzentrationen von glutarsäure, oh-glutarsäure und glutaconsäure im urin, ▬ evtl. bestimmung der glutarsäure im serum (normal <2µmol/l; hoffmann et al. 1996) . nach bisherigen erfahrungen soll die lysin-und tryptophanarme ernährung unter zusatz von aminosäurenmischung höchstens bis zum 6. lebensjahr durchgeführt werden, um dann auf eine gelockerte, eiweißreduzierte diät überzugehen. kontrolliert werden müssen darüber hinaus: ▬ gesamt-und freies carnitin im serum, ▬ ggf. die antikonvulsiva-blut-spiegel. eine generelle prognose bei der schweren form der glutaracidurie typ i ist nicht zu geben. isovaleryl-coa-dehydrogenase-defekt, isovalerianacidurie, iva. bei der isovalerianacidämie handelt es sich um einen defekt im abbau der isovaleriansäure, einem stoffwechselprodukt der verzweigtkettigen aminosäure leucin. schon in den ersten 3 lebenstagen kommt es zur anhäufung von isovaleriansäure und seinen metaboliten und damit zur ausbildung von schweren klinischen symptomen. bei milderen formen manifestiert sich die krankheit erst nach dem 6. lebensmonat (budd et al. 1967; mönch u. link 2002; sidbury et al. 1967; sweetman u. williams 2001) . die erkrankung kann mit der tandem-ms schon im neugeborenenscreening erfasst werden (vermehrung von c5); ihre häufigkeit liegt bei etwa 1:50.000 (ceglarek et al. 2002) . der eigengeruch der isovaleriansäure erinnert an schweißfüsse (schweißfusssyndrom). im neugeborenenscreening findet man keine besonderheiten bei den verzweigtkettigen aminosäuren. lediglich alanin und evtl. alloisoleucin sind erhöht. auffällig vermehrt sind isovalerylcarnitin (c5) im blut bei relativ niedrigem freien carnitin (c0) sowie die relationen einiger acylcarnitine untereinander (c5/c2, c5/c3; rashed et al. 1995) . in den ersten lebenswochen sind hyperammonämien nicht selten mit konzentrationen bis über 1.000 µmol/l (1.750 µg/dl) und hyperlaktatämien neben einer ketoacidose häufig. bei der analyse der organischen säuren im urin findet man das für diese krankheit typische ausscheidungsmuster (⊡ tabelle die für die behandlung notwendige flüssigkeitsmenge richtet sich nach dem dehydratationsgrad und ist abhängig vom alter und von der nierenfunktion des patienten. in den ersten 24 h infusion von mindestens 10 g/kg kg glukose mit elektrolyten (evtl. auch in kombination mit der natriumbikarbonatgabe); ggf. erhöhung der glukosemenge kann bis auf 20-30 g/kg kg. falls notwendig, sollte zusätzlich insulin (0,01-0,5 ie/kg kg und stunde) gegeben werden, um den glukoseblutspiegel zwischen 80 mg/dl und 200 mg/ dl zu halten. zur beendigung bzw. der vermeidung von katabolen stoffwechselzuständen ist eine hohe kalorienzufuhr (>100 kcal/kg kg und tag) notwendig. zusätzlich zu glukose sollte fett infundiert werden (am anfang 0,5-1 g/kg kg und tag sowie, wenn möglich, steigerung auf 2-3 g/kg kg und tag) unter kontrolle der triglyzeridkonzentrationen im blut. zur schnellen ausscheidung der stoffwechselmetabolite dient die forcierte diurese durch verabreichung von furosemid (lasix; 1-2 mg/kg kg oral oder 0,5-1 mg/kg kg i.v., alle 6-12 h). die infusionstherapie sollte am zweiten, spätestens am dritten tag durch proteingaben ergänzt werden. üblich ist der start mit 0,5 g/kg kg und tag natürlichem eiweiß (evtl. steigerung bis auf 1 g/kg kg und tag) und ggf. zusatz von 0,5 g spezieller, leucinfreier aminosäurenmischung/kg kg und tag (leu-am analog, leu-am 1-3 von shs, heilbronn; leu 1-2 von milupa, friedrichsdorf). im rahmen der medikamentösen therapie sollte zur bildung von isovaleriansäureestern verabreicht werden: ▬ l-carnitin (z. b. 100-150 mg/kg kg und tag, evtl. teilweise i.v.), ▬ glycin (100-280 mg/kg kg und tag). die gabe beider substanzen ist sinnvoll und effektiv. liegt eine hyperammonämie vor, erfolgt die behandlung mit gaben von: ▬ argininhydrochlorid initial 210 mg (1 mmol bei betroffenen jungen treten die hyperammonämien mit ihren charakteristischen symptomen in der regel schon in den ersten lebenstagen auf. ohne sofort einsetzende rigorose behandlung versterben diese patienten in den ersten lebenstagen/-wochen im hyperammonämischen koma (brusilow u. horwich 2001; mönch u. link 2002) . neben ammoniak sind bei der behinderung des harnstoffzyklus glutamin, glutamat, asparagin und alanin vermehrt. während ammoniak hirntoxisch ist, führt die hohe konzentration von glutamin zu osmotisch bedingtem einstrom von wasser in die zellen und damit zum hirnödem (mit der folge von einklemmungen). beim mangel an mitochondrialer otc wird das substrat des enzyms, carbamylphosphat, auf einem alternativen zytoplasmatischen stoffwechselweg zu orotat abgebaut, das mit dem urin ausgeschieden wird. dieser abbauweg ist aber nicht effektiv genug, um eine ammoniakvermehrung zu verhindern (brusilow u. horwich 2001; mönch u. link 2002) . mildere verlaufsformen sind bei jungen bzw. männern beschrieben. meist fallen sie nach einer eiweißbelastung (z. b. auch nach aminosäureninfusion) durch eine hyperammonämie und deren klinische manifestationen, z. b. enzephalopathie, auf. das klinische bild der klassischen/neonatalen form des otc-defektes (otcd) bei den betroffenen jungen ist in den ersten lebenstagen in der regel in abhängigkeit von der gegebenen eiweißmenge gekennzeichnet durch: ▬ lethargie, ▬ koma, ▬ krämpfe, ▬ erbrechen, ▬ hyperventilation (gelegentlich), ▬ hypotonie, ▬ hepatomegalie. wird in dieser phase die meist dramatisch erhöhte ammoniakkonzentration nicht nachhaltig gesenkt, versterben die jungen, oder es bleiben schäden mit symptomen wie (brusilow u. horwich 2001; maestri et al. 1996) : ▬ ernährungsschwierigkeiten mit häufigem erbrechen, ▬ neurologische auffälligkeiten, ataxien, ▬ geistige retardierung. bei late-onset-formen zeigen sich enzephalopathien, koma und krampfanfälle im jugend-bzw. erwachsenenalter nach reichlicher eiweißzufuhr oder auch aminosäureninfusion. bei mindestens 10% der heterozygoten mädchen zeigen sich je nach vorhandener enzymaktivität oder zellmosaiken klinische symptome, deren ausmaß von der zahl und dem schweregrad der durchgemachten hyperammonämischen krisen abhängt. bei den überträgerinnen werden besonders nach eiweißreicher nahrung episodenhafte krisen mit erbrechen, ataxie, kopfschmerzen und auch lethargie beobachtet (maestri et al. 1996 (finkelstein et al. 1990; pelet et al. 1990 ). zur sicherung der diagnose und zur genetischen beratung sollten die otc-aktivität im lebergewebe und eine genomische analyse durchgeführt werden. nur bei wenigen mutationen besteht eine relation zwischen genotyp und phänotyp (campbellet al. 1973) . zur erfassung der heterozygoten für otc-mangel sind belastungstests mit alanin, eiweiß oder allopurinol beschrieben (burlina et al. 1992) . (allopurinol blockiert den abbau von orotat. da bei minderung der otc-aktivität dessen substrat, carbamylphosphat, zu orotat abgebaut wird, steigt diese dann nach allopurinolgabe deutlich an.) der allopurinoltest zeigt leider sowohl falsch-positive testergebnisse bei gesunden als auch falsch-negative; deshalb werden nach wie vor trotz der gefahr einer hyperammonämie eiweißbelastungstests durchgeführt (carpenter et al. 1996). …therapie akutbehandlung erst-und notfallversorgung; mönch u. link 2002; mönch et al. 1998 ). akut-/notfallbehandlung begonnen werden, auch wenn die differenzialdiagnostischen untersuchungen noch nicht abgeschlossen sind. ziel der akutbehandlung ist es, die ammoniakkonzentration in jedem fall zu senken und eine anabole stoffwechselsituation zu erhalten bzw. zu erwirken. bei der einlieferung eines bisher klinisch unauffälligen patienten im koma ist an ganz unterschiedliche ursachen zu denken, und entsprechende maßnahmen sind zu ergreifen (⊡ abb. 8.3). generell kommen ätiologisch immer stoffwechselstörungen, aber natürlich auch traumen, hirnblutungen, intoxikationen, schwere infektionen u. a. infrage. die wahrscheinlichkeit des vorliegens einer metabolischen störung ist bei neugeborenen am größten, wenn hirnblutungen, sepsis und enzephalitis wenig wahrscheinlich oder ausgeschlossen sind. ! die unterbrechung der kompletten oralen eiweißzufuhr sollte nicht länger als 2 tage dauern. im folgenden findet sich eine zusammenstellung der medikamente (⊡ tabelle 8.37), die zur behandlung der beschriebenen angeborenen stoffwechselstörungen notwendig sind und deshalb in den kinderkliniken mit intensivmedizinischen abteilungen vorrätig sein sollten. die angaben erfolgen ohne anspruch auf vollständigkeit sowohl hinsichtlich der hersteller als auch der genannten präparate (dosierungen im text). obesitas, fettsucht. chronische erkrankung, bei der der pathologisch erhöhte körperfettanteil an der gesamtkörpermasse der betroffenen die grundlage drohender oder bereits manifester krankheitssymptome ist. die während die zahl übergewichtiger kinder und jugendlicher mit häufigkeitsangaben zwischen 15% und 20% in allen industrienationen ständig steigt, nimmt das ausmaß der adipositas bei den betroffenen ebenfalls bedrohlich zu. grundlage für die entstehung einer adipositas ist das bestehen einer positiven energiebilanz. dabei sind endogene und exogene faktoren zu beachten: ▬ endogen: der ruheenergieumsatz, der etwa 50% des täglichen energieverbrauchs ausmacht, die art der energiespeicherung und die regulation der energiebilanz unterliegen in ihrer steuerung verschiedenen hormonellen, aber auch genetischen einflussfaktoren. insgesamt haben mul tiple genetische variablen mit etwa 70% einen hohen anteil an der regulation der körperzusammensetzung. neuere untersuchungen zeigen, dass die ernährung in der säuglingszeit einen faktor für die langfristige entwicklung einer adipositas darstellt (»food programming«; kap. 15). ▬ alltagsaktivität : schulweg möglichst nicht mit dem auto, täglich mindestens 30 min. aktive bewegung, ▬ inaktivitätszeiten durch fernsehen und computerspiele auf 1-2 h am tag reduzieren, ▬ sport in der gruppe (spaßbetont, spielerisch, allmähliche steigerung der belastung). ▬ förderung von selbstwahrnehmung und selbstbewusstsein und der eigenverantwortung, ▬ intervention und remotivation bei misserfolg. die richtlinien der infusionstherapie entsprechen denen gleichaltriger. es ist je doch zu beachten, dass sich das energiegleichgewicht auf einem höheren le vel im vergleich zu normalgewichtigen befindet. diese tatsache muss berücksichtigt werden, da eine durch restriktion zusätzlich negativ beein fluss te energiebilanz in akuten krankheits-oder stresssituationen zu vermeiden ist (vgl. arbeitsgemeinschaft adipositas im kindes-und jugendalter 2003). essstörung mit selbstverursachtem gewichtsverlust oder inadäquater gewichts-(und größen-)zunahme in der adoleszenz. damit kommt es zum kreuzen der altersabhängigen gewichts-(und größen-)perzentilen nach unten. der bmi ( abschn. 8.5) liegt altersbezogen unter der 10. perzenlile. es besteht eine körperschemastörung mit einer trotz zunehmendem gewichtsverlust anhaltenden, intensiven angst, zu dick zu sein oder zu werden. durch störung der endokrinen achse hypothalamus-hypophyse-gonaden kommt es zu einer sekundären amenorrhö bzw. bei prämenarchealen mädchen zu einer stagnation der pubertären entwicklung. das verhältnis erkrankter mädchen zu jungen beträgt etwa 10:1 bis 15:1. der häufigkeitsgipfel der manifestation liegt bei 14 jahren. somatische ursachen eines gewichtsverlustes müssen unbedingt ausgeschlossen werden. essstörung gekennzeichnet durch rezidivierende essanfälle und intermittierende unangemessene gegenmaßnahmen zur gewichtsregulierung. die essanfälle treten 3 monate lang durchschnittlich 2-mal/woche auf. es besteht subjektiv ein kontrollverlust über art und menge der nahrung. in kurzer zeit werden übermäßig große kalorienmengen aufgenommmen (z. b. 800-5.000 kcal). unangemessene gegenmaßnahmen sind selbstinduziertes erbrechen, fasten, exzessives sporttreiben, missbrauch von laxanzien oder diuretika. es besteht die furcht, zu dick zu sein oder zu werden. das hauptmanifestationsalter liegt zwischen 18 jahren und 20 jahren. betroffen sind wiederum hauptsächlich frauen. bestehen essattacken ohne gegenmaßnahmen, bezeichnet man die störung als »binge eating disorder«. zwischen den formen der essstörung gibt es gemeinsamkeiten und übergänge. so unterscheidet man bei der anorexia nervosa einen restriktiven typ von einem »binge-eating/purging-typ«. letzterer beinhaltet neben den kriterien der anorexie rezidivierende essanfälle und purging-verhalten (unangemessene gegenmaßnahmen). wegen der mangelnden krankheitseinsicht besteht eine hohe dunkelziffer, insbesondere bei bulimie. bei der anorexie ist der erhebliche gewichtsverlust früher oder später die indikation zur arztkonsultation, oft auf initiative der eltern, manchmal sogar gegen den willen der patientin. eine ernährungsberatung ohne arztkonsultation darf nicht erfolgen. ein zusammenwirken unterschiedlicher faktoren führt zum krankheitsbild der essstörungen. das bestehen einer genetisch bedingten disposition mit unterschiedlicher penetranz ist die schlussfolgerung aus familienstudien. erhöhte unspezifische perinatale risikofaktoren ließen sich ebenfalls nachweisen. bestimmte persönlichkeitsmerkmale treten bei anorektischen patienten gehäuft auf: beharrlichkeit, rigidität, introvertiertheit, gesteigertes harmoniebedürfnis und hohe intelligenz. zwischen dem dadurch bedingten verhalten des kindes bzw. jugendlichen und dem erziehungsstil der eltern, manchmal geprägt durch autorität, »overprotection« und konfliktvermeidung, besteht eine enge wechselbeziehung. soziokulturelle faktoren mit einem schönheitsideal, das einem körperbild wie bei anorexie nahe kommt oder entspricht, können auslösend wirken. zusammenhänge zwischen psychopathologie und neuroendokrinium in bezug auf auslösung und verstärkung anorektischer und psychiatrischer symptome werden erforscht. körperliche symptome sind fast ausschließlich auf den zustand der starvation zurückzuführen und betreffen alle organsysteme ( unten). ausgeprägte somatische veränderungen im zusammenhang mit einem chronischen verlauf und mehreren rezidiven sind neben einer erhöhten suizidalität ursache dafür, dass die anorexie mit etwa 10% die höchste mortalität unter allen psychiatrischen erkrankungen hat. patienten mit bulimie sind oft normalgewichtig, manchmal auch adipös. auch hier gilt es, somatische ursachen der symptomatik auszuschließen und das ausmaß der organveränderungen zu eruieren. die anamnese soll immer mit einem elternteil bzw. einer anderen bezugsperson und patientin getrennt erfolgen. mehrere gespräche sind oft erforderlich. mangelnde krankheitseinsicht und schamgefühl können zu falschen angaben führen. bereits in der phase der diagnostik kann das hinzuziehen eines psychologen/kinderpsychiaters sinnvoll sein. eine sorgfältige klinische untersuchung ist in jedem fall unbedingt erforderlich. die ursachen der unterernährung krebserkrankter kinder sind der krankheits-und therapiebedingte appetitmangel sowie der ausgeprägte proteinkatabole stoffwechsel einer tumorkachexie. die kachexie unterscheidet sich im vergleich zum dominierenden fettverlust beim reinen fasten durch den zusätzlichen gravierenden substanzverlust körpereigener proteine, der besonders durch den massiven muskelschwund beeindruckt. indirekt kalorimetrische studien an erwachsenen zeigen nur bei etwa 25% einen wirklich erhöhten, bei etwa 30% sogar einen erniedrigten und sonst einen normalen grundumsatz (flancbaum et al. 1999 diese veränderungen einer im prinzip fehlregulierten hungersituation sind vermutlich folge der tumorbedingten imbalance von zytokinen, beispielsweise durch verstärkte aktivität von tumor-nekrose-faktor-α (tnf-α, früher kachektin) und anderen proinflammatorischen zytokinen, wie interleukin-(il-)1 und il-6. diese zytokine werden von lymphozyten und makrophagen sezerniert und repräsentieren möglicherweise eine immunantwort des organismus auf krebszellen. obwohl der genaue mechanismus nicht bekannt ist, kann durch applikation von tnf-α der kachexiephänotyp beim menschen nachgestellt werden (starnes et al. 1988 der grad der gewichtsabnahme krebserkrankter kinder wird durch art, lokalisation und stadium der erkrankung sowie durch die intensität der therapienebenwirkungen bestimmt. mit starker gewichtsabnahme ist während der zeit intensiver chemotherapiezyklen, radiotherapie und ausgedehnten chirurgischen eingriffen zu rechnen und wird durch übelkeit, erbrechen, geschmacksbeeinträchtigung, mukositis, ösophagitis sowie verminderte intestinale absorption aufgrund schleimhautschädigung und durchfällen verursacht. in ausgeprägten fällen kann eine ganzkörperbestrahlung mit hochdosischemotherapie als konditionierung vor stammzelltransplantation durch die induktion einer hochgradigen mukositis und die damit verbundenen starken schmerzen und durchfälle die enterale nahrungsaufnahme trotz intensiver schmerztherapie manchmal über wochen unmöglich machen. speziell in der extremsituation einer stammzelltransplantation konnte eine signifikant verbesserte überlebenswahrscheinlichkeit durch parenterale ernährung belegt werden und gilt daher als standard bei diesen patienten (weisdorf et al. 1997 ). bei der ernährungsanamnese sind remissionsstatus der krebserkrankung, die abgelaufene und geplante therapie, die gewichtsveränderung und das längenwachstum im zeitquerschnitt sowie die gewichtsentwicklungen und längen der eltern zu berücksichtigen. zur objektivierung der art und menge der tatsächlichen nahrungsaufnahme ist die kontinuierliche genaue buchführung der ernährung nützlich. bei der körperlichen untersuchung sollte besonders auf die fettreserven, muskelmassen, eventuelle eiweißmangelödeme und zeichen der mukositis geachtet werden. bei der erhebung anthropometrischer daten sind häufige gewichts-und regelmäßige längenmessungen sowie deren übertragung auf perzentilenkurven grundlegend. darüber hinaus ergeben fettfaltenmessungen und technische messungen der »body composition« beispielsweise mit der »dualenergy x-ray absorptiometry (dexa)« weitere wichtige hinweise über die art und die entwicklung des ernährungszustands. bei sehr großen tumoren sollte der ernährungszustand anhand der fett-und muskelreserven unabhängig vom gesamtgewicht beurteilt werden. aufgrund der komplikationsmöglichkeiten einer parenteralen ernährung und der lehrmeinung, dass eine enterale nahrungsaufnahme im vergleich zur parenteralen ernährung physiologischer wirkt, indem sie beispielsweise einer atrophie der intestinalen schleimhaut vorbeugt, ist die enterale ernährung prinzipiell vorzuziehen. da der wert einer forcierten ernährung für eine verbesserte überlebenswahrscheinlichkeit nicht gezeigt wurde, bei kindern eigentlich immer der intensive wunsch besteht, möglichst viel zeit zu hause zu verbringen, wo die kinder bei gewohnter kost und umgebung meistens auch deutlich besser essen als im krankenhaus, sollten in der regel empfehlungen für eine optimierte, primär orale ernährung in der häuslichkeit ausgesprochen werden. empfohlen werden sollten ausgewogene nahrungsmittel, die dem kind gut schmecken; im falle erheblicher unterernährung kann die nahrung mit hochkalorischen ernährungskomponenten, beispielsweise in form von hochkalorischer trinknahrung (»astronautenkost«) ergänzt werden. möglichkeiten, die orale nahrungsaufnahme zu verbessern, bestehen in der verteilung des essens auf mehrere kleinere mahlzeiten, in dem versuch, kühle speisen oder speisen kühl anzubieten, im angebot von speisen mit wenig geruchsentwicklung, in der auswahl weicher, nichtreizender speisen bei mukositis, in der behandlung einer geschädigten mundschleimhaut mit einem lokalen anästhetikum, im fernhalten von lieblingsspeisen in zeiten einer emetogenen therapie (vermeidung einer gelernten aversion) und ggf. in der verabreichung antiemetischer medikamente. im vorschulalter sollten 90-120 kcal/kg kg, bei älteren kindern 50-80 kcal/ kg kg angeboten werden. ob weitere maßnahmen bei sehr untergewichtigen kindern getroffen werden, muss individuell entschieden werden. hier sollte beispielsweise bei einem kind, das sich unter therapie befindet, anders abgewägt werden als bei einem bereits austherapierten kind in einem endstadium. bei kindern, die unter ausgeprägtem appetitmangel und untergewicht leiden, bei vigilanzverminderten kindern oder kindern mit schweren schluckstörungen kann der einsatz von nasogastralen oder nasoduodenalen ernährungssonden auch in der häuslichkeit erwogen werden. über solche sonden kann nahrung im intervall manuell oder kontinuierlich über pumpen appliziert werden. »perkutane endoskopische gastrostomie-(peg)-sonden« sind in fällen vorzuziehen, in denen eine langfristige lösung geschaffen werden muss. beim legen von sonden sollten die thrombozytenzahl und der gerinnungsstatus ausreichend sein. allgemeine vorsichtsmaßnahmen zur wahrung der sicherheit von nahrungsmitteln, um beispielsweise eine salmonelleninfektion zu verhindern, sollten für immungeschwächte kinder beachtet werden. ein infektionsprophylaktischer effekt allgemein bakterienreduzierter diäten konnte dagegen nicht gezeigt werden. kontrovers diskutiert werden solche maßnahmen bei sehr stark immunsupprimierten kindern, die beispielsweise allogen stammzelltransplantiert wurden. obwohl ein nutzen von manchen autoren bezweifelt wird (henry 1997) , werden solche vorkehrungen von manchen transplantationszentren nach wie vor getroffen. dies reicht von lediglich verkürzungen der haltbarkeitsdaten nach öffnung von verpackungen bis zur ernährung mit ausschließlich frisch sterilisierten produkten. bei sehr stark untergewichtigen kindern, die z. b. wegen schwerer mukositis oder anhaltend ausgeprägter appetitlosigkeit und übelkeit gar keine oder nur äußerst wenig nahrung enteral aufnehmen und für die eine nahrungssonde keine alternative darstellt, kann die parenterale ernährung erwogen werden. da bei schwerer mukositis häufig kontinuierliche morphin-gaben notwendig sind, müssen die kinder hierzu oft nicht einmal zusätzlich hospitalisiert werden. da kindern für die chemotherapie häufig ein permanenter zentraler venenkatheter chirurgisch implantiert wird, sind die technischen voraussetzungen in vielen fällen schon gegeben. kurzzeitig erholen sich krebspatienten von den direkten folgen einer intensiven chemotherapie oder ausgedehnter operation durch parenterale ernäh rung schneller. dabei muss erwähnt werden, dass neben dem fehlenden nachweis eines nutzens für die überlebenswahrscheinlichkeit zudem berichte auf ein erhöhtes infektionsrisiko unter parenteraler ernährung hinweisen (christensen et al. 1993 parenteral ernährte intensivpflichtige kinder beispielsweise mit schwerer infektion oder mit niereninsuffizienz müssen zusätzlich nach intensivmedizinischen grundregeln und besonders in bezug auf die flüssigkeitsbilanzierung genauestens überwacht werden. bei manchen kindern mit bestimmten zns-tumoren, bei kindern, die beispielsweise wegen einer akuten lymphatischen leukämie kortikosteroide erhalten und bei vielen kindern, die von einer leukämie geheilt wurden, entwickelt sich erhebliches übergewicht (didi et al. 1995) . hierfür werden verschiedene faktoren diskutiert, wie bewegungsarmut und anhaltende insulinresistenz. bei diesen kindern sollte die hormonelle situation geklärt werden und eine diätetische beratung über kalorienarme nahrungsmittel erfolgen. inwieweit bei austherapierten und sterbenden kindern eine künstliche ernährung enteral über eine sonde oder sogar parenteral durchgeführt werden sollte, muss individuell zusammen mit der betroffenen familie entschieden werden. hier sollte zu jedem zeitpunkt besonderes augenmerk auf die verbliebene lebensqualität des kindes gelegt werden. besonderheiten bei kindern mit rheumatischen erkrankungen fragen zur diät von kindern mit autoimmunologischen erkrankungen sind häufig und die publikationen hierzu in der laienpresse irreführend. erschwerend wirken sich die medizin-historisch begründete unscharfe abgrenzung der rheumatoiden arthritis von der arthrose und der arthritis urica (gicht) aus. validierte wissenschaftliche untersuchungen, insbesondere bei kindern und jugendlichen bilden die ausnahme und vermitteln ein oft widersprüchliches bild. bei den meisten autoimmunologischen erkrankungen fehlen kontrollierte diätetische studien völlig. bei den kindlichen arthritisformen, der juvenilen idiopathischen arthritis (jia, einteilung nach klassifikation der ilar; petty et al. 1998 ) liegen zwar untersuchungen vor; hierbei wurden die einzelnen untergruppen der erkrankung jedoch häufig nicht differenziert betrachtet. grundsätzlich müssen bei rheumatischen erkrankungen 3 diätetische ansätze betrachtet werden: ▬ eliminationsdiäten und fastenkuren in der absicht einer reduktion entzündungsfördernder nahrungsstoffe, ▬ substitutionsdiäten mit dem ziel der zufuhr entzündungshemmender nahrungsstoffe, vitamine oder spurenelemente, ▬ diätetische prävention von sekundärschäden der erkrankung und therapie. immer wieder wird nach einem zusammenhang zwischen lebensmitteln und dem auftreten rheumatischer beschwerden gesucht. mögliche zusammenhänge zwischen nahrungsmittelunverträglichkeiten und gelenkbeschwerden wurden mehrfach beschrieben. kontrollierte studien hierzu sind jedoch auch bei erwachsenen selten. nahrungsmittelunverträglichkeiten spielen offenbar nur in individuellen ausnahmefällen bei der jia eine rolle (falcini et al. 1999; schranderet al. 1997 (purdy et al. 1996) und immer einen erhöhten kalorienbedarf . eliminationsdiäten erscheinen daher nur bei einer nachgewiesenen nahrungsmittelunverträglichkeit sinnvoll, während von fastenkuren bei rheumatisch erkrankten kindern-und jugendlichen generell abzuraten ist. ziel ist hierbei eine antioxidative und/oder antiinflammatorische wirkung durch gezielte zufuhr bestimmter nahrungsbestandteile. hintergrund sind beobachtungen einer verminderten inzidenz rheumatischer erkrankungen bei populationen mit einem hohem anteil von fischölen in der nahrung (eskimos). darüber hinaus konnte tierexperimentell eine deutliche reduk tion proinflammatorischer zytokine unter einer mit ω3und ω6-fettsäuren angereicherten diät beobachtet werden. vitamin e zeigte demgegenüber allein keine signifikante wirkung, hatte jedoch einen synergistischen effekt mit der ω3/6-diät (venkatraman u. meksawan 2002) . kinder mit einer jia haben inadäquate serumkonzentrationen antioxidativer vitamine (a, e) und spurenelemente (zink; helgeland et al. 2000; silverio amancio et al. 2003) . es wurde bei kindern mit einer jia nur eine kontrollierte studie zur substitu tion von ω3-fettsäuren durchgeführt (alpigiani et al. 1996) . ähnlich den ergebnissen bei erwachsenen mit einer ra (adam 2003; james u. cleland 1997) zeigten sich nur marginale verbesserungen bezüglich morgensteifigkeit und der anzahl der schmerzhaften gelenke. kontrollierte studien zur substitution antioxidativer vitamine und spurenelemente bei patienten mit einer jia fehlen bislang. kinder und jugendliche mit einer jia leiden an einer erkrankungsbedingten verminderung der knochendichte (henderson et al. 1997 ) und des skelettwachstums (cassidy u. hillman 1997) . der erkrankungsbeginn und der therapeutische einsatz systemischer kortikosteroide spielen hierbei eine entscheidende rolle (brik et al. 1998; celiker et al. 2003) . neben der qualitativen veränderung des knochens führen sowohl die grunderkranknung wie auch der einsatz von steroiden zu einem verminderten längenwachstum. auch hier sind nur wenige kontrollierte studien mit kleinen probandenzahlen berichtet. der einsatz von biphosphonaten zeigte keine relevante verbesserung der knochenmineralisierung (lepore et al. 1991) , während der einsatz von rekombinantem humanem wachstumshormon bei steroidtherapierten jia-patienten sowohl die knochenqualität als auch das längenwachstum verbesserte (rooney et al. 2000) . die therapeutische substitution von kalzitonin und kalzium zeigte bei patienten mit einer polyartikulären bzw. systemischen jia eine verminderung der knochenresorption. die studie wurde jedoch nicht placebokontrolliert und nicht mit der erkrankungsaktivität korreliert (siamopoulou et al. 2001) . die therapie mit niedrig dosiertem methotrexat (»low-dose mtx«) hat die behandlungserfolge auch in der kinderrheumatologie revolutioniert. beunruhigend waren daher befunde bei erwachsenen mit einer ra, die unter einer low-dose-mtx-therapie einen anstieg der homocysteinwerte im plasma zeigten; dies korreliert mit einem erhöhten risiko für kardiovasku läre erkrankungen. die substitution mit fol-bzw. folinsäure führte zu einer reduktion des plasmahomocysteins ohne verminderung der antirheu matischen wirkung von mtx (van ede et al. 2002) . eine pilotstudie bei jia-patienten konnte diesen positiven effekt einer folsäuresubstitution auf die hyperhomocysteinämie jedoch nicht nachvollziehen (huemer et al. 2003) . ein eindeutig positiver effekt der folsäuresubstitution bei kindern mit jia, die mit einer low-dose-mtx-therapie behandelt werden, wurde bezüglich der hepatotoxischen und gastrointestinalen nebenwirkungen von mtx gezeigt (ravelli et al. 1999) . die arbeitsgemeinschaft kinder-und jugend rheuma tologie (agkjr) empfiehlt daher beim auftreten derartiger neben wirkungen unter mtx-therapie die substitution von folsäurederivaten (niehues et al. 2003) . eindeutig gezeigt werden konnte auch die erhöhte bioverfügbarkeit von mtx nach oraler applikation auf nüchternen magen (dupuis et al. 1995 (sampson 1999) . die ersten diagnostischen und therapeutischen ansätze werden daher oft schon im säuglingsalter gestellt. je jünger die kinder zum zeitpunkt des auftretens der allergischen symptome sind, desto größer ist die chance, dass sich diese bis zum schulalter wieder verlieren (burks et al. 1988 ). zirka 80% der nahrungsmittelallergien verschwinden im laufe der ersten 4-5 lebensjahre wieder. obwohl wir täglich eine vielzahl unterschiedlicher nahrungsmittel zu uns nehmen, wird die mehrzahl der allergischen reaktionen nur durch wenige nahrungsmittel ausgelöst.zirka 85% der kinder reagieren hierbei nur auf 1 oder 2 nahrungsmittel (crespo et al. 1995; niggemann et al. 1999 ohne ausreichende diagnostik sollten keine diäten durchgeführt werden. sie können das kind sinnlos beeinträchtigen und zu erheblichen mangelzuständen führen. undifferenzierte diäten entheben den therapeuten ungerechtfertigt von der verantwortung und verhindern sinnvolle therapiemaßnahmen. so ist die frage der diät bzw. der ernährung des kindes bei einer nahrungsmittelallergie eng verbunden mit der frage der fehlernährung, des normalen wachstums und des gedeihens des kindes. eine professionelle beratung durch eine ernährungsfachkraft ist daher unerlässlich. ernährung und (leistungs-)sport sport stellt eine besondere herausforderung für den organismus dar, auch für den kindlichen. abhängig von der art der sportlichen aktivität werden die kapazitäten, z. b. des atmungssystems, des herz-kreislauf-systems und der energiebereitstellung, sowie die muskuläre kraftentwicklung trainiert. bei planvoller und wiederholter durchführung kommt es zu anpassungsprozessen mit verbesserter körperlicher leistungsfähigkeit. zudem dient sport der prävention zahlreicher erkrankungen, wie adipositas, diabetes mellitus und hypertonie. in abhängigkeit der durchgeführten sportarten stellt sportliche aktivität besondere anforderungen an die nahrungszufuhr: zum einen an die menge zugeführter energieträger, zum anderen an die zusammensetzung. außerdem ist die flüssigkeitszufuhr von besonderer bedeutung. nicht vergessen werden darf, dass im laufe der kindheit eine zunehmende anpassung an die ernährungsformen und -gewohnheiten im erwachsenenalter stattfindet, eine wichtige lebensphase, in der die grundlagen für das spätere essverhalten gelegt werden. natürlich ist die bedarfsdeckung mit allen wichtigen nährstoffen bedeutsam, allerdings sollte eine abwechslungsreiche lebensmittelauswahl im vordergrund stehen. eine adäquate energiezufuhr ist für kinder im hinblick auf die prävention von über-bzw. untergewicht von großer bedeutung. sportliche aktivität steigert den täglichen energieverbrauch. wenngleich keine exakten zahlen für kinder vorliegen, so wird davon ausgegangen, dass kinder beim sport im vergleich zu erwachsenen relativ betrachtet mehr energie verbrauchen. ein 7-jähriges kind würde beispielsweise für eine vergleichbare belastung 25-30% mehr energie benötigen als ein erwachsener, 8-bis 10-jährige verbrauchen ca. 20-25% mehr energie und 11-bis 14-jährige ca. 10-15%. diese geringere energetische effizienz bei kindern resultiert wahrscheinlich aus noch nicht hinreichend ausgebildeten koordinativen fähigkeiten. zusätzliche muskelkontraktionen, z. b. eine unzureichende abstimmung zwischen agonistisch und antagonistisch arbeitenden muskelgruppen, »kosten« extra energie. ⊡ tabelle 8.41 gibt eine übersicht bezüglich der richtwerte für die durchschnittliche tägliche energiezufuhr im kindes-und jugendalter. als kontrolle für eine adäquate energieaufnahme dient das aktuelle körpergewicht. im vergleich zu erwachsenen verbrauchen kinder während körperlicher aktivität im rahmen der energiebereitstellung anteilig mehr fett und weniger kohlenhydrate. dennoch gibt es keine evidenz dafür, dass sportlich aktive kinder deshalb anteilig mehr fett mit der nahrung aufnehmen sollten als weniger aktive. bei kindern unter chemotherapie mit platinderivativen (cisplatin, carboplatin) besteht ein vermehrter bedarf an magnesium. daher wird magnesium bei diesen kindern über den basalen bedarf hinaus substituiert daher wird seit langem ein möglicher vorteil durch zusätzliche glutamingaben diskutiert ebenfalls unklar ist die pharmakologische bedeutung 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(9 s.) . katorsx~, b. a.: the influence of growth hormone on fat and protein metabolism. diss. abstr. 23 [1962] nr. 6, 63--1036 (55 s. amer. j. clinical nutrition 12 [1963] nr. 6, s. 431ff. (6 s.) . mxmo~, j. e.: the influence of diet and age on lipid metabolism of chickens. diss. abstr. 23 [1963] nr. 10, 63-1951 (63 s.) . *me, i, f. : a study on the lipid metabolism in the patients with atherosclerosis especially on the cholesterol in serum lipoprotein fl-fraction. japan. heart j. 4 [1963] nr. brown, l. d., grev~es, 1%. m., u. duncan, c. w. : effect of protein level in milk replacers on growth and protein metabolism of dairy calves. j. dairy sci. 46 [1963] nr. 6, s. 538ff. (6 s.) . *ma~i)elst~, j. : protein turnover and its function in the economy of the cell. arm. new york acad. sci. 162 [1963] nr. 3, s. 621ff. (16 s.) . mast~as, c. j. : nucleic acids and protein stores in the merino sheep. australian j. biol. sci. 16 [1963] nr. 1, s. 192ff. (9 s.) . noack, r.: zur biochemischen funktion des proteins als grundlage der bedarfsaormen. ernehrungsforschung 8 [1963] nr. 1, s. 15/24. *par.r. anin, a. u : le m6tabolisme pro~ique dans le systems nel-ceux. studii si cercet~ri de biochimie 6 [1963] nr. 1, s. 7ft. (16 s.) . roouski, j., ~i[akowska, k., i~sn~, j., stankowska, a., hryniewiecki, l., u [1963] nr . 42 [1963] . suppl. to nr. 1, s. 453ff. (8 s.) . co~solazio, c. f., ~ixtous~, l. 0., nv. lson, r. a., ~[a~drng, r. s., u. can" a~, j. e.: excretion of sodium, potassium, magnesium, and iron in human sweat and the relation of each to balance and requirements. j. nutrition 79 [1963] nr . goodwin, a. f., u sci. 42 [19631 nr. 1, s. 202ff. (4 s.) . *gerlinger, p., much, j.-v., u. clukvert, j.: note pr4liminaire sur raction du eyclophosphamide (endoxan) sur le d6veloppement de l'embryon. c. r. acad. sci. 255 [19621 nr. 23, s. 3229ff. (3 s. [19621 nr. 6, 62-5407 (110 s.) . nelson, f. e., jensen, l. s., u *caruzzo, c., tartara, d., pagano, p. g., pellegrini, a., costanzo, f., u [1963] nr. 10, 63--2084 (126 s.) . 38 [1963] nr. 6, s. ll0ff. (5 s.) . gal/~bos, j. t., asada, m., u. s~ks, j. z. : the effect of intravenous ethanol on serum enzymes in patients with normal or diseased liver. gastroenterology 44 [1963] nr. 3, s~ 267ff. (12 s.) . gall, c., u. weissw~.~le~, p. : un~ersuchungen fiber die labf~higkeit der milch und ihre beziehung zur mineralsteff-fiitterung der kfihe. milchwissenschaft 17 [1962] nr. 8, s. 413ff. (? s.) . zitat: dt. lebensmittel-rdsch. 59 [1963] nr. 4, s. 123 . gasic, g., u. morrison, a.b.: mucopolysaccharides of renal collecting tubule ceils in potassium deficient rats. prec. soc. exper. biol. med. 112 [1963] l~r. 4, s. 871ff. (2 s.) . gear~-, t. f. : oak wilt development and its reduction by growth regulators. i. production and activity of oak wilt fungus pectinase, cellulase, and auxin. ii. effect of halogenated benzoic acids on oak trees, the oak wilt diseases, and the oak wilt fungus. diss. abstr. 23 [1962] nr. 6, 63--650 (102 s.) . *g~l~,~cs~,r, f., g~ti, t., gy~g~, k., u. s6s, j.: effec~ of cardiopathogenic diet on the thiopental anaesthesia. acts physiologica aead. sci. hung. 1963 suppl. nr. 22, s. 16 . gar~'ls, j., piazu~lo, e., u [1962] nr. 6, 62--5595 (116 s.) . ikir~a, h., u. t~, k. v. : activity of gibberellin 'd' on the germination of photosensitive lettuce seeds. nature 197 ] nr. 4874, s. 1313 /1314 die wirkung des glucagons auf den blutzuckerspiegel in abh~ngigkeit yore alter. z. aiternsforsch. 16 [1963] nr. 3, s. 206/210. *loosli, j. k. : primary signs of nutritional deficiencies of laboratory animals. j. amer. veter, reed. assoc. 124 [1963] nr. 9, s. 1001 ft. (4 s.) . lowrey, r. s., pond, w. g., lo0sli, j. k. u. barnes, r. h.: effect of dietary protein and fat on growth, protein utilization, and carcass composition of pigs fed purified diets. j. animal sci. 22 [1963] nr. 1, s. 109ft. (6 s.) . lvnd, c. c., u. ) [1963] nr. 1, s. 32ff. (5 8.) . nr~cleod, l. b. : effect of liming and potassium fertilization on soil solution and on yield and composition of alfalfa and orchard grass mixtures. dlss. abs~r. 23 [1962] nr. 6, 62--5826 (322 s.) . ~ds~n, k. 0., u. edmonds, e. j. : prolonged effect on caries of short-term feeding of rice hulls to cotton rats. j. dental res. 42 [1963] nr. 1, s. 137ff. (9 s.) . m~a~.~, a. c. : biological responses of young rats fed diets containing genistin and genistein. j. nutrition 89 [1963] nr. 2, s, 151] 156. ~_ajaj, a.s., dnc~g, j.s., azzam, s.a., u. da_~by, w. j.: vitamin e responsive megaloblastic anemia in infants with protein-calorie malnutrition. amcr. j. clinical nutrition 12 [1963] nr. 5, s. 374 ft. (6 s.) . 1v~jcm~owicz, e., u. quxstel, j. h. : effects of aliphatic alcohols on the metabolism of glucose and fructose in rat liver slices. canad. j. bioehem. physiol. 41 [1963] nr. 3, s. 793ff. (12 s.) . m_al~otra, o. p., n~a-wl)ov, a.v., r~ber, e. f., u. norton, h . w., effects of rat strain, stilbestrol, and testosterone on the occurrence of hemorrhagic diathesis in rats fed a ration containing irradiated beef. j. nutrition 79 [1963] nr. 3, s. 381ff. (8 8,) . --, u. r~ber, e. f. : effect of methionine and age of rat on the occurrence of hemorrhagic diathcsis in rats fed a ration containing irradiated beef. j. nutrition 80 [1963] nr. 1, *misga, u. k. : effect of corn oil feeding on the lipids of dog bile. indian j. exper. biol. 1 [1963] nr. 2, s. 87/90. * miyao, m., tsvn•isnz, m., nagano, k., u. ttosogi, t.: experimental studies on the digestibility and absorbability of milk proteins. 4. effects of carbohydrate addition on the digestibility and absorbability of cow's milk proteins. tokushima j. exper. med. 9 [1962] nr 1963, nr. 5334, s. 846ff. (4 s.) . nagra, c. l., brerrenbach, r. p., u. meyer, 1~. k. "-influence of hormones on food intake and lipid deposition in castrated pheasants. poultry sci. 42 [1963] nr. 3, s. 770ff. (6 s.) . *+na~:ler, w. g.: the significance of calcium ions in cardiac excitation and concentration. amer. heart j. 65 [1963] nr l~, b. l., u. re(~a~, w. s., u. dobozy, a.: effect of vitamin a on the nucleic acid metabolism of rats. acts biologics acad. sci. hungariae 1963, suppl. 5, s. 46 . 01~itz, k., u. loeser, a. : uber den einflufl appetithemmender substanzen auf das fettgewebe. klin. wschr. 41 [1963] nr. 4, s. 1931196. *0rstadius, k., nordstrom, g., u. lannek, n. : combined therapy with vitamin e and selenite in experimental nutritional muscular dystrophy of pigs. cornell veterinarian 53 [1963] nr. 1, s. 60ft. (9 s.) . ern~hrung und therapie. med. u. ern~hrung 4 [1963] nr. 6, s. 146/150 . *--pflanzliche polysaccharide zur steigerung der kiirpereigenen abwehr. ivied. welt 1963, nr. 6, s. pxrkrnson, t. m., u. 0lso~r, j. a. : inhibitory effects of bile acids on the uptake, metabolism, and transpor~ of water-soluble substances in the small intestine of the rat. life sci. 1963, nr. 6, s. 393] 398. *pxl~o% j.-l., u. mord~l~t-dx~rin~, )i..' action du potassium et du calcium sur l'histaminopexie s~rique. recherches sur le cobaye, le rat et l'homme. j. physiol. 54 [1962] nr. 4, s. 579ff. (12 s.) . * patek, a. j., de fr1tsc] t, n. m., kendall, f. e., n. hirsch, r. l.: corn and coconut effects in dietary cirrhosis of rats. arch. pathology 75 [1963] nr. 3, s. 264ff. (7 s.) . patil, s. s.: the relation of ehlorogenic acid and total free phenols in potato plants to resistance to infection by verticillum alboatrum. diss. abstr. 23 [1962] nr. 6, 65--5602 (92 s.) . petuet,y, f.: diskussionsbemcrkungen zu rcferaten fiber sauermilchprodukte auf einer vortragsveranstaltung der gesellsehaft fiir erniihrungsbiologie e.v., miinchen, 22. juni 1961 . milchwissensehaft 18 [1963 nr. 5, s. 236] 237. pfei~ter, (3. j., gass, g. h., u. schw~rz, (3. s.: reduction by chlorpromazine of ulcem due to acute starvation in mice. nature 197 [ ] nr. 4871, s. 1014 1015. prrrllros, a. w., newc0m~, tl r., u. sha.wklrs, d. r.: long-term rat feeding studies on irradiated chicken stew and irradiated cabbage. toxicol. appl. pharmacol. 5 [1963] nr. 3, s. 273]297. prrmt~s, p. h., sutti~, j. w., u. ze~rowski, e. j. : effects of dietary sodium fluoride on dairy cows. vii.: recovery from fluoride ingestion. j. dairy sei. 46 [1963] l~r. 6, s. 513ff. (4 s. browi~, t. h., u. levee, r. v.: the effect of milk intake on nematode infestation of the lamb. prec. nutrition 8oc. 22 [1963] nr. 1, s. 32/41. * srnwrvasan, m., n~o~bhusha_~a~, a., u. sm~rrvas~, k. s.: changes in serum inorganic phosphate following ingestion of protein. curr. 8ci. 32 [1963] nr. 1, s. 21. stallwoth, h. : some effects of 2.4-dichlorophen-oxyacetie acid on sweet corn (zea mays rugosa l.) with emphasis on yield, tillering, root development, and exudation of electrolytes from roots and stems. diss. abstr. 23 [1963] nr. 8, 62---6233 (79 s.) . starcher, b., u. i~.ratzer, f~ h.: effect of zinc on bone alkaline phosphatase in turkey poults. j. nutrition 79 [1963] nr. 1, s. 18/22. stei~-~off, d., u. ~rqu~lrdt, p. : kombination yon kaliumpyrosulfit und ~xthy]alkohol ira tr~nkungsversuch an ratten. arzneimittelforschung 13 [1963] nr. 3, s. 237/238. stevermer, e. j. : influences of level of nutrition of the boar and of ionic environment of the spermatozoa on the properties of boar semen. diss. abstr. 23 [1962] nr. 6, 63--619 (104 s.) . stn~p~., f., u. 8c~warz, k.: incorporation of valine-l-x*c into serum and tissue proteins of rats fed torula yeast diets. j. nutrition 79 [1963] nr. 2, s. 151/160. 8ton~., d. b., u. co~or, w. e. : the prolonged effects of a low cholesterol, high carbohydrate diet upon the serum lipids in diabetic patients. diabetes 12 [1963] nr. 2, 8.127 ft. (6 s.) . *stormont, j. •., u. waterhouse, c. : effect of variations in previous diet on fasting plasma lipids. j. labor. clinical med. 61 [1963] nr. 5, s. 826ff. (6 s.) . * stuart, a. e., u vity of the heart extract of rats. medlcina exporimentalis 7 [1962] nr. 6, s. 363ff. (5 s.) . szepsenwol, j.: carcinogenic effect of egg white egg yolk and lipids in mice. prec. soc. exper. biol. med. 112 [1963] nr. 4, s. 1073ff. (3 s.) . *t~cs, l, u. ny~i, i.: effect of saline infusion, acth infusion, and blood transfusion on the hormone excretion of patients with hypereme~is. act~ medics aead. sei. hun. garicae 18 [1962] nr. 4, s. 385ff. (14 s.) . tanner, j. w.: an external effect of inorganic nitrogen on nodulation. diss. abstr. 23 [1963] nr. 10, 63--3007 (50 s.) . --, u [1963] nr. 4, s. 308ff. (13 s.) . *t~i~er, l., m~az, m., u. cs:menafiov4, m. : the effect of glucose and glucose together with insulin on the resistance of fasted rats to trauma in the noble-collip drum. physiologia bohemoslovenica 12 [1963] nr. 2, s. 136ff. (9 8.) . ude~iend, s. : factors in amino acid metabolism which can influence the central nervous systems. amer. j. clinical nutrition 12 [1963] nr. 4, s. 287ff. (4. 8 .) vahouny, g. v., moede, a., silver, b., n . treadw~ll, c. r. : nutrition studies in the cold. iv. effect of cold environment on experimental atherosclerosis in the rabbit. j. nutrition 79 [1963] nr. 1, s. 45/52. van p1lsum, j. f., olsen, b., taylor, d., rozyc'ki, t., u voss, r. d.: yield and foliar composition of corn as affected by fertilizer rates and environmental factors. i)iss. abstr. 23 [1963] nr. 10, 63--3008 (293 s.) . *vyval,ro, i. g. : the effect of gibberellin on the transformation of substances in germinating corn seeds. i)oldady akad. nauk sssr [russ.] 149 [1963] nr. 4, s. 979ff. (3 s.) . wao~ei~, g. r., cl~mk, a. j., hays, v. w., u amer. j. clinical nutrition 12 [1963] lgr. 3, s. 235ff. (6 s.) . the assessment of marginal protein malnutrition. prec. nutrition soc. 22 [1963] mr. 1, s. 66]72. --, u. stnp~, j. m. l.: the free ly~ine and amino nitrogen content of liver, muscle, and serum in normal and protein-depleted rats. prec. nutrition soc. 22 [1963] mr. i, s . viii/ix. *watson, w. c.: the morphology and lipid composition of the erythrocytes in normal and essential-fatty-acid-deflcient rats. bri6. j. haematology 9 [1963] lgr. 1, s. 32ff. (7 s.) . waite, r., u. : blackburn, p. s. : the relationship between milk yield, composition and tissue damage in a case of subclinical masticis. j. dairy res. 30 [1963] 1963, nr. 5330, s. 561ff. (1 s.) . *n. n.: paraty1~hoid fever from frozen chinese eggs. brit. reed. j. . (1 s.). *n. n. : radioactivity and human diet. chem. ind. 1963, nr. 18, 8. 721 . ~q. ~.: 8eh~digungen dutch konservlerungsmittel bei zitrusfrfichten? dr. reed. wschr. 88 [1963] nr. 17, s. 927. *n. n. : salt-poisoning in infancy. lancet 1 [1963] l~r. 7293, s. 1251. n.n.: kouoquium des arbeitskrcises hamburg der gdch-fachgruppe lebensmittelchemic und gerichtliche chemic am 7. januar 1963 . lebensmittelchem. u. gerichtl. chem. 17 [1963 nr. 6, s. 1161118. *n. n. : smoking and heath disease. new england j. med. 268 [1963] nr. 15, s. 903. +hi. n. : toxic components of lathyrus peas. nutrition rev. 21 [1963] nr. 1, s. 28/30. +n. n. : cariogenic ability of different diets. nutrition roy. 21 [1963] nr. 2, s. 50]52. +n. 1~.: aminoaeiduria in lead intoxication. nutrition rev. 21 [1963] nr. 3, s. 75/76. +n. n. : pyridoxine and dental caries. human studies. nutrition rev. 21 [1963] nr. 5, s. 1431145. +n. n.: pyridoxine and dental caries. animal studies. i~utrition rev. 21 [1963] nr. 5, s. 1451147. +hi. n. : rcporb: the prophylactic requirement and the toxicity of vitamin d. pediatrics 31 [1963] nr. 3, s. 512ff. (? s.). axrkroa, a.: caesium-137 from fall-out in human milk. nature 197 [1963] nr. 4868, s. 667ff. (1 s.) . *allcroft, r., u. car~agha~, r. b. a. : groundnut toxicity: an examination for toxin in human food products from animals fed toxic groundnut meal. veteri. rec. 75 [1963] nr. 10, s. 259ff. (5 s.) . *--, l~wis, g., u. hill, k. 1~.: groundnut toxicity in cattle: experimental poisoning of calves and a report on clinical effects in older ca~tle. ve~er. rcc, 75 [1963] nr, 19, s. 487ff. (6 s. nr. 1, 2, 3 nr. 1, 2, 3, 4, 5 nr. 1, 2 nr. 1, 2 influence of calcium and ouabai bain upon potassium influx in human erythrocytes the enzymatic assimilation of nitrate in the tomato plant translocation of '~p, i~n, and ~c in plants einige neue gesiehtspunktr zum caleiumstoffwechsel dis~ibution of water, sodium, and potassium in resting and stimulated mammalian muscle. canad the influence of vitamin bi, on calcium ('sca) metabolism of maxillodental tissues kidney, water, and electrolyte metabolism intermediiirer elektroly~toffwechsel und zellgrenzfl~chenphysiologie im theoretischen zusammenhang mit der krebsentstehtmg. tell i dcr einflul~ yon vollkornbrot auf den calcium-stoffwechsel bei schulkindern recherches sur le m6tabolisme du soufre. x. : la non-6quivalence de la eystine et de la eyst4ine dans la couvcrture des besoins sufr~s du rat adulte potassium-magnesium antagonism in soils and crops low serum iron levels in obese adolescents metal content of human organs studies on the requirements and interaction of copper and iron in broad breasted bronze turkeys to 4 weeks of age iron absorption and excretion in experimental iron deficiency the measurement of exchangeable magnesium in dogs the copper metabolism of warmblooded animals with special reference to the rabbit and the sheep comparative studies of the metabolism of strontium and barium in the rat the utilization of iron in erythropoiesis binding of strontium in blood ~iolybdenum, copper, and zinc contents of mouse liver and sarcoma 180 treated with molybdenum compounds biochemical effects of zinc deficiency in tomato plants excretion of sodium, potassium, magnesium, and iron in human sweat and the relation of each to balance and requirements turnover rate of zinc in the body as determined by the study of 6szn in rats a study of the iron absorption in mice as modified by various agents funktionsteste des radiojodstoffwechselstudiums und ihre bedeutung in der diagnostik der sehilddrfisenerkrankungen. ~rztl. laboratorium 9 the fate of radioiodine after parcnteral administration a possible humeral regulator of iron absorption beitrag zur kl~rung der ursachen der anreicherung yon caesinm-137 im 0rganismus blood-and serum-level of watersoluble vitamins in man and animals significados metabslicos do ~cido ~-lip6ico. 3. o ~cido r162 e o metabolismo do ferro observations on a magnesium-fluoride interrelationsip in chicks prevention of ,meat anemia" in mice by copper and calcium iron metabolism in experimental pyridoxine deficiency aluminium in soils and plants on the coastlands of british guinea physiology of adolescence. ii. : nutrition -basal oxygen consumption -energy expenditure and balance -nitrogen metabolism -calcium metabolism -iron metabolism -red cell mass and hemoglobin dietary strontium and calcium, and deposition of 89sr and asca in the bones of rats -~iengenelementansatz wachsender sehweine bei unterschicdiichen cuso4-zulagen differences in copper retention in two strains of chickens untersuchungen fiber anreicherung und verteilung yon rubidium in gerstenkcimpflanzen 112 [1963] nr. 3, s. 631/636. *+lv~ointyr~, i.: an outline of magnesium metabolism in health and disease. a review uptake by the root and subsequent distribution within the potato plant of strontium-89 leached from the foliage nor zinkstoffwechsel in der schwangerschaft foetal metabolism of caesium-137 in the rat magnesium metabolism of chickens zinc metabolism in patients with the syndrome of iron deficiency anemia hepatospenomegaly dwarfism, and hypogonadism. labor. clinical mcd c~isium-137 trod kalium in menschlichen organen und in der milch 1959/60 l~ole of the genotype in controlling accumulation of strontium-89 by plants copper and zinc interrelationships in the pig effect of chromium, cadmium, and other trace metals on the growth and survival of mice studies in the metabolism of zinc. iv. some observations on the urinary zine-porphyrin relationship in non-porphyries and in a patient with aeutm intermittent porphyria aastrontium balances in man studies on zinc metabolism. ii.: effect of the diabetic state on zinc metabolism: an experimental aspect effect of diabetic state on zinc metabolism: a clini. cal aspect copper metabolism and the liver iron metabolism and the liver with particular reference to the pathogcnesis of haemachromatosis studies on iron metabolism uber den eisenstoffwechsel. (bemerkung zu t. su~di~, miinchener reed yifinchener reed. wschr. 105 [1963] nr. 19, s. 99911000. 2c -7 wirkstoffe -biocatalysts +n. n. : vitamin a in human livers. nutrition biological half.llfe of vitamin b~ in plasma hypervitaminosis a and mast cells. a study of the interrelationship of mast cells and vitamin a in vivo and in vitro evidence concerning the human requirement for vitamin bi~. use of the whole body counter for determination of absorption of vitamin blz vitamin c in plasma and leucocy~s of smokers and non-smokers some factors affecting the absorption of vitamins the determination of vitamin a in animal tissues and its presence in the liver of the vitamin a deficient rat metabolic activities of vitamin a and related compounds in animals. i.: role of vitamin a in intestinal muscular contraction zum vitamin-b--haushalt dcr ratte bei sorbitfiitterung contribution a l'~tude do la relation entre la vitamine big et la glande thyrolde effects of deficiencies of certain b vitamins and ascorbic acid on absorption of vitamin blv amer ascorbic acid metabolism in plants. ii. : biosynthesis dietary and thyroid interrelationships affecting vitamin a status of feedlot beef cattle die wirkung gesteigerter kupferzufuhr auf den vitamin-c-haushalt vom meerschweinchen bei parental zugeffihrter ascorbins~ure kritische auswe~ung der naeh 1949 erschienenen arbeiten fiber gebundene ascorbins~ure im tierischen gewebe metabolism and biological activity of vitamin a acid in the chick biochemical studies of vitamin metabolism in poultry urine. ii. : on the excretion of thiamine in poultry urine after subcutaneous and oral administrations of some thiamine derivatives untersuchungen fiber die speiehcrung und fiber die ansscheidung yon vitamin a nach ungeniigender vitamin-a-versorgung bei legenden hfihnern studies on metabolism of vitamin a. 1.: the biological acticity of vitamin a acid in rats vitamin a and cholesterol absorption in the chicken studies on the interaction of vitamin bi~, intrinsic factor, and receptors. il the possible absorption of intrinsic factor human growth hormone in infant malnutrition macro-and micromethods for the determination of serum vitamin a using trifluoroacetic acid the activation of sulphate by extracts of cornea and colonic mucosa from normal and vitamin a-deficient animals the importance of blood as a pool of vitamin d studies on metabolism of vitamin a. 2.: enzymic synthesis ~nd hydrolysis of phenolic sulphates in vitamin-a-deficient rats human metabolism of l-ascorbie acid and erythorbic acid tissue distribution and storage forms of vitamin b~, injected and orally administered to the dog relation between vitamin a, tocopherol, and cholesterol serum levels in the elderly interrelationships of vitamin bi~, folio held, and ascorbie acid in the megaloblastie anemias zum wirkungsmechanismns des vitamins e. helvetica physiologica et pharmacologica effect of some physiologic factors on the absorption of vitamin bi~ in rats transport of dietary nitrogen mitochondrial fatty acids of fish and fish-eating birds the biosynthesis of fatty acids influence of age and dietary protein on cerbain free amino acids in chick blood plasma nitrogen metabolism in coldexposed rats ~ber des vermehrte auftreten yon fettsiiuren mit 10 bis 14 c-atomen in den depotfetten siiugender ratteu und den ubergang der linolsi~ure yon den mfittern auf die jungen die bildung yon antiksrpcrn gegen verschicdene kuhmilehproteine bei neugeborenen, kindern, erwachsenen und graviden the myocardial arterio-venous differences of free amino acids and of free fatty acids in healthy individuals, patients with diabetes and with essential hypercholesterolemia urinary amino acids on phenylalanine-tyrosine-supplemented diets difference in the metabolic fate of acetate and ethanol fed to higher plant tissues iiemodynamic relationships of anaerobic metabolism and plasma free fatty acids during prolonged, strenuous exercise in trained and untrained subjects effects of palmitate on the metabolism of leukooytes from-guinea pig exudate the dynamics of plasma free fatty acid metabolism during exercise ~ber die retention, den abbau und die ausseheidung yon 2-thion-tetrahydro-l.3.5-thiadiazinen transport systems for amino acids effects of protein intake and cold exposure on selected liver enzymes associated with amino acid metabolism quantitative studies on tryptophan metabolism in the pyridoxine-deficient rat effect of desoxypyridoxine-induced vitamin b~ deficiency on polyunsaturated fatty acid metabolism in human beings studies on the wheat plants using carbon-14 compounds. xix.: observations on the metabolism of lysine-14c. canad genetic defects of amino acid metabolism. pediatric clinics north america metabolism of tryptophan in diabetes mellitus the two-carbon chain in metabolism der einfluss yon vitamin a auf den citronens~urestoffwechsel ~)ber phenolspeicherung und phenolabbau in wasserpflanzen. naturwissensehaften 50 effect of physical exercise on nitrogen balance in obese subjects metabolism of nitrogen compounds in the rumen of ruminants. izvest. acad der intermedli~r-stoffwechsel s~ffweehsel der carotine im hiihnerembryo nucleic acid metabolism of germinating corn seedlings carbon metabolism of ~4c-labelled amino acids in wheat leaves. ii.: serine and its role in glycine metabolism bovine metabolism of insecticides. the metabolism of ~evin in dairy cows stoffweehsel der carotine. wiss. veroff. dr. oes. ern~hrnng 9 metabolism of labelled linolcic-l-tac acid in the sheep rnmen nonessential nitrogen supplements and essential amino acid requirements. nutrition rev vitamin c requirements of man re-examined. new values based on previously unrecognized exhalatory excretory pathway of ascorbie acid studies on the requirements and interaction of copper and iron in broad breasted bronze turkeys to 4 weeks of age water requirements of men as related to salt intake evidence for a high zinc requirement at the onset of egg production effect of lysine and glyeine upon arginine requirement of guinea-pigs the cobalt requirement of subterranean clover in the field fluid and electrolyte, requirements of newborn infants with intestinal obstruction the requirement and availability of dietary iron for young pigs studies on the protein and methionine requirements of young bobwhite quail and young ringnecked pheasants phenylalanine requirement of women consuming a minimal tyrosine diet and the sparing effect of tyrosine on the phenylalanine requirement effects of starvation on the cardiovascular system of the chicken calcium and phosphorus requiremeats of finishing broilers using phosphorus sources of low and high availability water intake of normal children sex differences in the ~4oeopherol requirement of rats as shown by the haemolysis test further studies on protein and energy requirements of chicks selected for high and iow body weight smoking and blood dotting dental caries and trace elements a statement approved by the board of directors of the canadian heart foundation the question of fats. il : fats and disease moldy peanuts and liver cancers vitamin c and healing of wounds berieht fiber die vortragstagung des fachverbandes lehensmittelchemie der chemisehen gesellschaft in der d])r veto 19. his 21 diet and human depot fat ethanol and plasma free fatty acid in man dietary water and protein efficiency in rats. nutrition rev. 21 [1963] nr. 1, s. 16/17. +n. n. : nature of the coagulation defect in rats fed diets producing thrombosis or experimental atheroselerosis factors affecting growth depression by raw soybeans bones in undernourished animals. nutrition rev. 21 [1963] nr. 1, s. 21123. +n. n. : vitamin e and the etiology of muscular dystrophy in the rabbit riboflavin eoenzymes and congenital malformations the thyroid gland in infant malnutrition. nutrition rev. 21 [1963] nr. 1, s. 32. +n. n. : a proposed mechanism for the effect of fats on serum cholesterol effect of varying levels of dietary protein on synthesis and excretion of urea dietary phosphates and dental caries folic acid restriction and cancer inhibition changes induced by lipoie acid in normal rat liver vitamin b6 deficiency and tryptophan metabolism effect of ubichromenol on development of encephmomalacia in vitamin e deficient chicks leucine-induced hypoglycemia nutritional muscular dystrophy in lambs. nutrition rev. 21 [1963] nr. 4, s. 120/122. +n. n.: amino acid imbalance in cold-exposed rats. nutrition rev. 21 [1963] nr. 4, s. 1221124. +n. n.: milk and athletic performance effect of vitamin a deficiency on the ubiquinone content of rat liver idiopatjaie stea~orrhea gastrointestinal protein loss in iron-deficiency anemia nutritional cirrhosis of the liver. nutrition rev. 21 [1963] nr. 6, s. 175/178. +n. n. : exercise and heart disease calcium deficiency in the etiology of osteoporosis the relation of dietary fat to the fatty acids in the intestinal wall clot-strength and elot-lysis in rats fed hyperlipemic diets effect of potassium iodide and duodenal powder on the growth and organ weights of goitrogen-fed rats ver~nderungen im stoffwechsel und wachsturn junger tomatenpflanzen nach giberillins~,urebehandiung effect of restricted feeding during the growing period on reproductive performance of large type white turkeys keys, a. l glucose, sucrose, and lactose in the diet and blood lipids in man ambient temperature and survival on a protein-deficient diet some considerations of changes in total body composition in relation to nutritional status the effect of variations in the energy and protein levels of the ration upon performance in the pig studies in choline deficiency. fate of injected 1-1~c-pal. mitio acid and fatty acid spectra in fasting and refed rats bartou i~ vitamin a requirements of chicks at moderately elevated temperature influence of age and dietary protein on eer~ain free amino acids in chick blood plasma the effects of nicotine on weight increment, activity, food intake, and water intake in weanllng albino rats effect of pyridoxine deficiency upon delayed hypersensitivity in guinea-pigs vitamin a deficiency in chickens ccrebellar encephalomalacia produced by diets deficient in toeopherol vitamin b12 deficiency in indian infantm plasma liplds in scurvy: effect of ascorblc acid supplement and insulin treatment effect of gibberellin on the variations of the growth-point in winter wheat uptake of dinitrophenol and its effect on transpiration. calcium accumulation in barley seedlings l~[ethylmalonate excretion in vitamin b~ deficiency reduction of plama cholesterol levels in atherosclerosis by diet and drug treatment. australasian ann effects of reduced dietary intake on the activities of various enzymes in the livers and kidneys of growing male rats the effect of feeding d-methionine on the d-amino acid oxidase activity of chick tissues l~etabolic effects of dietary protein level in cold-exposed rats relative effects of rapeseed oil and corn oil on rats subjected to aclrenalectomy, cold, or pyridoxine deprivation metabolic effects of dietary protein level with caloric restriction in coldexposed rats. canad metabolic effects of three dietary protein levels fed isocalorically to coldexposed rats. caned die nolle versehiedener fette im eiweis des organismus. nahrung the bursa of fabricius and xanthine oxidase activity of liver and kidney following dietary supplementation of iodina~d casein to chickens effects of linolsate and dietary fat level on plasma and liver cholesterol and vascular lesions of the cholesterol-fed rat a comparative study of the effect of bile acids and cholesterol on cholesterol metabolism in the mouse, rat, hamster, and guineapig the effects of ruminal and plasma sodium concentrations on the sodium appetite of sheep effect of level and sequence of feeding and breed on ovulation rate, embryo survival, and fetal growth in the mature ewe inhibitory effects of carbohydrates on histamine release and mast cell disruption by dextran fett-s~urestoffwechsel bci the effect of calcium infusions, parathyroid hormone, and vitamin i) on renal clearance of calcium nutritional supplementation during pregnancy effect of level of dietary protein with and without added cholesterol on plasma cholesterol levels in man die schilddrfisenfunktion bei enteralem eiweiflverlust effects of pelleting and varying grain intakes on milk yield and composition fatty acid composition of lipids of serum and aorta in the chicken on different diets rat intestinal suerase. ii.: the effects of rat age and sex and of diet on suerase activity the effect of selenium administration on the growth and health of sheep on scottish farns die wirkung yon vitamin b 6 bei leukopenien effect of energy source and level of alfalfa pellets on growth and tissue hpids of beef calves effect of magnesium deficiency on mast cells and urinary histamine in rats histamine-liberating effect of magnesium deficiency in the rat zur wirkung des wassers bei der seitenwurzelbildung an luftwurzeln influence of the aqueous potato extract and its fractions on growth and spore formation of the b. pumilus and the production of the antibiotic tetaine influence of mineral nutrition on the resistance of peach tree to fusicoceum amygdali de la croix the effect of dietary protein on the course of various infections in the chick bifidus intestinal flora in infants fed on mamysan b. acta paediatriea 52 effect of food fats on concentration of ketone bodies and citric acid level in blood and tissues is there a hemostatie effect of peanuts in hemophilioid disorders? milk allergy in infancy dental effects of fluoridation of water with particular reference to a study in the united kingdom influence of previous feeding with a high-fat diet on liver steatosis produced by acute starvation of growth hormone in mice effect of amino acid imbalance on nitrogen retention. ii.-interrelationships between methionine, valine, isoleucine, and threonine as supplements to corn protein for dogs supplementation of cereal proteins with amino acids. v. : effect of supplementation lime-treated corn with diffe. rent levels of lysine, tryptophane, and isoleueine of the nitrogen retention of young children the interrelation of nutrient supply, leaf nutrient content, and vegetative growth of ilex crenata gastric content of fasted primates. a survey serum cholesterol in vitamin c deficiency in man the effect of carbohydrates on the production of staphylococcal pigment effect of a low dietary level of three types of fat on reproductive performance and tissue lipid content of the vitamin b6-defieient female rat effect of magnesium deficiency on synthesis of hear~ and liver mit~chondria phospholipids ~ber den einflub l~nger dauernder ksrperlicher inaktivit~t auf die blutzuckerkurve nach oraler glucosebelasttmg. helvetica medica acts 30 action of trace elements on the metabolism of fluoride zur frage des einflusses yon kondensmilch und einer protein-valerina-polyphosphat-komplexverbindung auf die kreislaufwirktmg des kaffees beim menschen modifications de la croissance de la plantule de lapin blanc (lupinns albns l.) provoqu6es par une diminution exp6rimentale des r6serves influence of the dietary protein level on the magnesium requirement effects of high levels of copper and chlorotetracycline on performance of pigs effect of dietary calcium lactate and lactitic acid on faecal escherichia coli counts in pigs die entwickhing von calcium-mangelsymptomen. z. pflanzenern~hrung, diingung, bodenkde. 100 [1963] nr. 1, s. 53/58. --calcium-mangelsymptome an hsheren pfianzen copper deficiency in relation to swayback in sheep. i. : effect of molybdate and sulphate supplements during pregnancy long-term, low fat, low protein diets and their effect on normal trappist subjects further studies of the influence of diet on radiosensitivity of guinea-pigs, with special reference to broccoli and alfalfa effects of the infusions of ammonia, amides, and amino acids on excretion of ammonia answirlmngen langfristig fettreicher ern~ihrung auf das plasma-cholesterin the relationship of dietary energy level and density to the growth response of chicks to fats influences of dietary carbohydrate-fat combinations on various functions associated with glycosis and lipogenesis in rats. i. effects of substituting sucrose for rice starch with unsaturated and with saturated fat compensatory carcass growth in steers following protein and energy restriction fatty acid composition and glyceride structure in rats fed rapeseed oil or corn oil. canad influence of selective and nonselective hydrogenation of rapeseed oil on carcass fat of rats. canad studies in serum lipids. with special reference to spontaneous variations and the effect of short-term dietary changes experimentelle untersuchungen zur wirkung yon kaffeefett evaluation of the effect of breed on vitamin be requirements of chicks 1-iigh salt content of western infant's diet: possible relationship to hypertension in the adult the effect on the serum cholesterol levels of the consumption of a special dietary fat with a high content of unsaturated fatty acids in elderly people effect of dilution of the diet with an indigestible filler on feed intake in the mouse effect of tea and its tannins upon capillary resistance of guinea-pigs food input and energy extraction efficiency in carassins auratns effect of calcium and magnesium upon digestibility of a ration containing corn oil by lambs effects of calorie restriction during the growing period on the performance of egg-type replacement stock effects of insulin on hepatic glucose metabolism and glucose utilization by tissues cellulase and polygalacturonase in tomato fruits and the effect of calcium on fruit cracking effect of nutritional muscular dystrophy and of starvation on amino acid penetration in rabbit tissues plasma protein synthesis in nutritional muscular dystrophy inulin and sucrose distribution in tissues of vitamin e-deficient and control rabbits protein-bound dyes in the serum and liver of rats fed aminoazo dyes vanadium. excretion, toxicity, lipid effect in man the influence of vitamin a status on the proteoly~ic activity of lysosomes from the livers and kidneys of rats disauxie metainfettive e da malnutrizione induced drinking in dogs: comparative effects of hypertonic sodium chloride and sorbitol the influence of early nutrition on brain cholesterol accumulation during growth changes in composition of the saliva of cows on grazing heavily fertilized grass. res. veter changes in composition of the saliva of sheep on feeding heavily fertilized grass efect of varying alfalfa: barley ratios on energy intake and volatile fatty acid production by sheep the influence of calcium on the secretory response of the submaxillary gland to acetyi-choline or to noradrenaline clinical dentistry and fluoride food allergy as a cause of abdominal pain the effect of various dietary levels of ddt on liver function, cell morphology, and ddt storage in the rhesus monkey effect of natural and purified diets on survival of x-irradiated mice effect of autoclaving and ])'sine supplementation of skimmilk-powder diets on growth and caries in rats effects of alcohol intake on subjective and objective variables over a five-hour period nitrogen metabolism of african cattle fed diets with an adequate energy feeding value of fl-caroteno following treatment with n~o~ the relationship of the quantity and quality of dietary fats to serum cholesterol levels in men of different ages and weights effects on girls of greater intake of milk, fruits, and vegetables effect of antioxidant, protein, and energy on vitamin a and feed utilization in steers the growth-maintaining activity of ascorbic acid the effects of an induced pyridoxine and pantothenie acid deficiency on excretions of oxalic and xanthurenic acids in the urine influence of lactose and dried skim milk upon the magnesium deficiency syndrome in the dog. i.: growth and biochem chronic malnutrition in turkey. v. study on serum fatty acids in malnourished children the effect of nutrition conditions on the growth of and nitrogen accumalation by fodder beans when sown together with indian corn effects of a diet high in polyunsaturated fat on the plasmalipids of normal young females citrate and action of vitamin d on calcium and phosphorus metabolism beeinflussung der sportliehen lelstungsf/~higkeit durch eine geeignete er-nehrung effect of dietary erotic acid on liver proteins effect of barbiturie acid and ehlortetraeyeline upon growth, ammonia concentration, and urease activity in the gastrointestinal tract of chicks effects of feeding low levels of dimethoate on milk and whole blood eholinesterase activity of dairy cattle changes in serum lipoproteins after a large fat meal in normal individuals and in patients with isehemic hear~ disease the relationship of specific nutrient deficiencies ~) antibody response in swine. i. : vitamin a. ii. : pantothenie acid, pyridoxine or riboflavin. i)iss. abstr relationship of specific nutrient deficiencies to antibody production on swine. i. : vitamin a relationship of specific nutrient deficiencies to antibody production in swine. il : pantothenic acid, pyridoxine or riboflavin histechemistry of dietary cardiac lesions effect of various levels of fluorine, stilbestrol, and oxytetraeycline, in the fattening ration of lambs uptake of copper and its physiological effects on chlorella vulgarls the effects of a small dose of ethyl alcohol on certain basic components of human physical performance. i. the effect on cardiac rate during muscular work. arch. internat some effects of feeding stilbestrol, chlortetracycline and penicillin with alfalfa soilage on steer performance and carcass quality experimental induction of ciguatera toxicity in fish $hrough diet effects of potassium fertilizer, age of ewe, and small magnesium supplementation on blood magnesium and calcium levels of lactating ewes the influence of higher volatile fatty acids on the intake of urea-supplemented low quality cereal hay by sheep un~emuchungen fiber den umsatz wachsender schweine ab geburt. 2. mitt eczema and cow's milk. brit. med. j. 1963, nr. 5332, s. 753. isaacso~, a. : the effects of zinc on responses of frog skeletal muscle effects of zinc on responses of skeletal muscle effect of diet on work metabolism carbohydrate-phosphorus metabolism in the skeletal muscles of epinephrectomized animals durlng treatment with cortisone and vitamins c and p. ukrainskii biokhimichnii zhurnal composition of dietary fat and the accumulation of liver lipid in the choline-deficlent rat nutrition and palatability the incidence of protein-calorie malnutrition of early childhood theories on the mode of action of fluoride in reducing dental decay saccharase deficiency, familial entailing intolerance ~ cane sugar. acts paediatrica 52 raw and heat-treated soybeans for growing-finishing swine and their effect on fat firmness effect of the administration of isoniazid and a diet low in vitamin be on urinary excretion of oxalic acid dietary and thyroid interrelationships affecting vitamin a status of feedlot beef cattle ration effects on rumen acids, ketogenesis, and milk composition. i.: unrestricted roughage feeding the effect of supplements of groundnut flour or groundnut protein isolate fortifed with calcium salts and vitamins or of sklmmilk powder on the digestibility coefficient, biological value and net utilization of the proteins of poor indian diets given to undernourished children a comparison of skin-testing with natural foods and commercial extracts die wirkung yon hungern auf den ammoniakgehalt und das ph der pansenfi(issigkeit sowic auf die harnstoff-, cholesterin-und zuckerkonzentration im blu~. acts veterinaria acad increase of plant virus infection by magnesium in the presence of phosphate effect of intramuscular injection of magnesium sulphate solution on the growth rate and serum composition in rats diskussionsbemerkungen zu referaten fiber sauermilchprodukte auf einer vortragsveranstaltung der gesellschaft fiir eru~ effect of massive sodium bicarbonate infusion on renal function excessive insulin response to glucose in obese subjects as measured by immunoehemical assay die wirkung gesteigerter kupferzufuhr auf den vitamin-c-hanshalt yon meerschweinehen bci paren~ral zugef'dhrter ascorbinsrure the influence of growth hormone on fat and protein metabolism. dies. abs~r. 23 [1962] nr phenolearbons~iuren in mensehlichen nahrungsprodukten. zum vorkommen yon phenolcarbons~uren in mensehlichen nahrungsprodukten und ihr einflul~ auf den intermedit~ren stoffwechsel influence of pregnancy and an oxidized lipid diet on the fatty acid composition of blood and tissue an experimental approach to the mechanisms of weight loss. ii. 9 a comparison of effects of thyroxine, fat-mobilizing substance (fms) and food deprivation in achieving weight loss in mice fat accumulation in the regenerating media of arteries in rats given an atherogenic diet the effect of nutrition on the growth of faseiola hepatica in its snail host the effects of specific viruses, virus complexes, and nitrogen nutrition on the growth, flowering, and mineral composition os strawberry plants body weight and food intake as initiating factors for puberty in the rat 9 the role of catecholamines in the free fatty acid response to cigarette smoking die renale steroidausseheidung bei experimentellem vitamin-e-mangel 9 peculiar features of respiration and redox processes in the rice plants grown under different nutritional conditions der bohnenkaffee und die migrrne repeatability of litter size and weight in the laboratory rat as affected by selection and plane of nutrition wirkungen yon muskelextrakt auf den stoffwechsel. arzneimittelforschung is [1963] nr. 3, s. 238/239 einflul] der silageftitterung auf die qualit~t der butter einflul] der silageftitterung auf die qualit~t yon milch und milchproduk. ten. 3. mitt.: einflul] von silagefiitterung auf die organoleptischen eigenschaften dcr milch effect of protein intake and cold exposure on selected liver enzymes associated with amino acid metabolism body iron levels and hematologic fin. dings during excess methionine feeding der einttul~ des kulturmediums auf die bildung von streptolysis s durch ruhcnde zellen influence of polyphosphates in chilling water on quality of poultry meat influence of breed-type, feed level, and sex on characteristics of the lamb carcass, and some relationships among live animal and carcass measurements the toxic action of phenothiazine and some disturbances of intermediary metabolism in undernourished sheep efficiency of feed use in beef cattle uber die wirkung der nalmmgsfette auf die blutlipoide, teil i. ernahrungs-umsehau 10 [1963] nr. 8, s. 174/176. --~ber die wirkung der nahrungsfette auf die blutlipide fette und blutgerinnung. bibliothcca hacmatologiea effect of heavy cigarette smoking on postprandial triglycerides, free fatty acids, and cholesterol role of calcium in fibrin formation glucose-6-phosphate dehydrogcnase and aldolase in lenses of lactose-fed rats -effect of riboflavin, choline, pantothenic acid and vitamin a on the excretion of sodium in urine of rats the effect of waterwashed rice in the diet on the growth, excretion of sodium in urine and blood pressure of rats effect of aseorbic acid, vitamin b, and milk on the dark adaption effect of single deficiency of vitamin a, thiamine der einflub yon vitaminen auf die psyehomotorisehe leistungsi'~higkcit beim menschen. naunyn-schmiederberg's arch. exper feeding response of adult tribolium to carbohydrates in relation to their utilization nutritional secondary hyper hieronymi: influence of nutritional conditions on the cellular rna metabolism in rive and in vitro diffusible auxin increase in a rosette plant treated with gibberellin transamination in muscular dystrophy and the effect of exogenous glutamate: a study on vitamin e deficient rabbits, and mice with hereditary dystrophy. canad effect of auxin on the emergence of lateral roots in p. mungo seedlings the effect of nutritive status on oestrus, ovulation, and graafian follicles in merino ewes biologische wirkungcn autoxydierter, epoxydierter und bestrahlter fette s~ure-basen-gleichgewicht mad chronische acidogene und alkalogene eruehrung effect of protein level in milk replacers on growth and protein metabolism of dairy calves effect of sodium bicarbonate in the drinking water of ruminants on the digestibility of a pelleted complete ration sucrose diet and bfliary chelate excretion in rats: with note on procedure for chelate determination eirdlub sauerer milcherzeugnisse auf die darmflora untersuchungen fiber die speicherung und die ausscheidung yon vitamin a nach ungenfigender vitamin-a-versorgung bei legenden hiihnern the effects of low magnesium intake on lactating ewes effect of vitamin a on the content of pyridinnucleotides, pyrovic, and lactic acid and on anaerobic phosphorylation. ukrainskii biokkimichnii zhurnal the pyridine nucteotides. a study of a method of measurement. a study of the alterations in rat fiver under the conditions of diabetes and starvation. a preliminary study of various marine fish tissues with the emphasis on the islet of langerhans iron uptake-transport of soybeans as influenced by other cations hshe und zeitpm~kt der dfingung yon sommerweizen mit chlorcholinchlorid zur vcrkiirzung der halmlange nutritional significance of soluble nitrogen in dietary proteins for ruminants effects of long-term feeding of vegetable fats on atherosclerosis effects of feeding various mile, corn, and protein levels on laying performance of egg production stock some observations on the influence of a magnesiumdeficient diet of rats, with special reference to renal concentrating ability effect of gibberellic acid on flowering of apple trees the effects of dietary fat and energy levels on the performance of caged laying birds motivational producing properties of the feeding system of the rat hypothalamus the influence of diet and age on lipid metabolism of chickens effect of age on the response of chickens to dietary protein and fat absorption and excretion of biotin after feeding minced liver in achlorhydria and after partial gastrectomy variations de la calcsmie du chien normal apr~s ingestion de cholesterol eristallis~ dans l'6thanol ou dans rhexane changes in activity of rat epididymal adipose tissue in vitro due to time elapsed since last feeding differences in rat strain response to three diets of different compositions l'alcoolisme ~ l'hspital psychiatrique de colsou (martinique). ann. m~dico-psychologiques 1 nitrogen, lipid, glycogen, and deoxyribonu. eleie acid content of human liver. the effect of brief starvation and intravenous administration of glucose some metabolic and nutritional factors affecting the survival of erythrocytes erythrocyte survival of rats deficient in vitamin e or vitamin b 6. j. nutrition 80 [1963] nr. 2, s. 185/190 nutrition and lactation the effect of administering sodium chloride, sodium bicarbonate, and potassium bicarbonate to newly born piglets strontinm-90 and calcium in milk of miniature swine further studies on cariostatic effect of organic and inorganic phosphates urinary excretion of magnesium in man following the ingestion of ethanol the effects of magnesium compounds and of fertilizers on the mineral composition of herbage and on the incidence of hypomagnesaemia in dairy cows behavioral, dietary, and autonomic effects of ehlordiazepoxide in the rat the effect of a high and low sodium diet in a patient with familial periodic paralysis the effect of quaternary ammonium anion exchange resin on plasma and egg yolk cholesterol in the laying hen vitamin e deficiency and ion transpor~ in rat liver slices effect of level of nitrogen on growth and reproductive physiology of young buus and rams influence of low protein rations on growth and semen characteristics of young beef bulls, if treatment of nutritional cirrhosis in rats with choline and methionine; with special reference to fibrogenesis and fibroelasia probleme der beurteilung yon sauermilcherzeugnissen. milchwissen. schaft 18 [1963] nr. 5, s. 228/231. --antwort auf die diskussionsbemerkungen auf einer vortragstagung der gesellschaft ffir ern~hrungsbiologie e. v., miinehen, am 22 response of early-weaned pigs to variations in dietary calcium level with and without lactose effect of low calcium diet on bone crysta]linity and skeletal uptake of 4sca in rats response of rural guatemalan indian children with hypocholesterolemia to increased crystalline cholesterol intake source of plasma free fatty acids in dogs receiving fat emulsion and heparin alcoholic intoxication in the newborn infant. bril mcd dental caries of rats fed a rice diet and modifications a study of zinc deficiency in the dairy calf effects of different levels of zinc and phosphorus on the growth of subterranean clover (trifolium subterraneum l) lrber den einflu8 yon fluor auf den wassergehalt des knochens gegevens ovvr vitamine b,-deficientie, -behoefto en -voorziening the liquefying action of pancreatic, cereal, fungal, and bacterial co-amylases ern~ihrung und endokrines system 1. mitt.: der einfiul3 der erniihrung auf die schilddriise the effect of saline water on kidney tubular function and electrolyte excretion in sheep zinc and iron deficiencies in male subjects with dwarfism and hypogonadism but without ancylostomiasis, schistosomiasis or severe anemia die yextriiglichkeit yon xyli~ beim diabetiker einflni3 der laevulose auf die fu~ionsbrelte. sport~tl. praxis der einflul~ yon vitamin a auf den zitronensi~urestoffwechsel studies on the growth-promoting value and digestibility of passion fruit seed oil ration effects on drylot steer feeding patterns dextrothyroxine on metabolism of cholesterol some effects of feeding lactates to dairy cows copper deficiency problems in south-east scotland bone changes in iron deficiency anaemia a preliminary report on nucleic acid levels in mineral deficient plants metabolism of histidine in protein malnutrition ttypoglycemie effect of l-leucine during periods of endogenous hyperinsulinism nutritional studies with the guinea-pig. viii. : effect of different proteins, with and without amino acid supplements, on growth some effects of sulphur-containing amino acids on the growth and composition of wool effects of hunger and vi value on vi pacing potency of conditioned reinforcem based on food and on food and punishment sfibwaren und karies in theorie und praxis effect of magnesium on the changes of myocardial potassium confent untersuchungen fiber den einflub oral verabreiehten oxytetraeyclins auf leberlipide und serumeholesterin der weil~en ratte further studies on manganese nutrition of tobacco in relation to virus infection and synthesis aminobutyric acid (),-aba)-vitamin be relationships in the brain serum lipids and diet: a comparison between three population groups with low, medium, and high fat intake effects of light and gibberellin on elongation of intact wheat coleoptiles experimental magnesium deficiency in the cow thyroid function in chickens and rats: effect of iodine content of the diet and hypophysectomy on iodine metabolism in white leghorns cockerels and long-evans rats kuhmilehallergie beim sgugling und a rapid method for assessing drug inhibition of feeding behavior variation in, and the effects of vitamins on vertieillinm albo-atrnm influence of high level vitamin a supplement on semen characteristics and blood composition of breeding bulls influence of diet on viral hepatitis der einflul] der stiekstoffdfingung auf die zusammcnsetzung yon karf~ffeleiweib insulin response to fructose and galactose the effect of excess vitamin a on the oxygen consumption of young female rats effect of dietary amino acid pattern on plasma ~mino acid pattern and food intake gibbere/lln: effect on diffusible auxin in fruit development effect of intravenous versus oral fat administration in fat-deiicient dogs plasma vitamin bi~ levels in some nutritional deficiency states nutritional factors influencing the conversion of tryptophan to niacin pancreatic hypertrophy and chick growth inhibition by soybean fractions devoid of trypsin inhibitor production, interior egg quality, and some physiological effects of feeding raw soybean meal to laying hens effect of palm jaggeries on the growth and blood and liver composition of albino rats kept on rice and jowa effects of polyphosphates on water uptake, moisture retention, and cooking loss in broilers untersuchungen fiber den ern~hrungsphysiologischen wer~ yon kasein entgegnung zu diskussionsbemerkungen auf einer vortragsveranstaltung der gesellschaft for ern~ihrungsbiologie e. v., mfinchen, am 22. juni die erg~nzungswirkung yon dl-methionin allein oder in kombination mit l-lysin beim wachsenden schwein der einflul~ der nahnmg auf den kauapparat der einflu6 der nahrung auf den kauapparat. teil il changes in bone mass and density in living rats during the manipulation of calcium intake effect of chromium, cadmium, and other trace metals on the growth and survival of mice a study of fermentation in the production of mahewu, an indigenous sour maize beverage of southern africa the vitamin b~ deficiency syndrome in human infancy, biochemical and clinical observations lipids in chick urine: the influence of dietary rapeseed oil effects of dietary nitri~ on the chick" growth, liver vitamin a stores, and thyroid weight influence of radioactive sodium-24 on higher nervous activity of dogs, when chronically administered into the organism in comparatively small doses 9 the change of erythroeyte blood composition in persons with prolonged complete alimentary starvation (without limiting the water intake) and subsequent feeding dental abnormalities in rats attributable to protein deficiency during reproduction the effect of environment, and nutrition of pathogen and host, in the damping off of seedlings by rhizoctonia solani effect of dietary protein on fructose, citric acid, and 5-nucleotldase activity in the semen of bulls the effect of fluorine on dairy cattle. v. : fluorine in the urine as an estimator of fluorine intake some effects of diet and therapy on the survival and metabolism of adrenalectomized rats effect of methonine and choline deficiency on liver choline oxidase activity in young rats untersuchungen fiber die wasserlssliehen hemmstoffe aus dem 8chnittholz der weinrebe (vi~is vinifera l.). i. zur wirkung der hemmstoffe auf die keimlmg mad entwicklung yon rebs~mlingen nutrition and palatability. lancek 11 the effect of feeding fluoride on some enzymes of bovine tissues diet and histamine in the rmninant effect of food reflexes on cholinestera~e activity of cortical tissue. federation essential fatty acid deficiency and rat liver homogenate oxidations the effect of vitamin and antibiotic injections on early turkey poult growth and mortality alimentary production of gallstones in hamsters. 12. studies with rice starch diets with and without antibiotics nitrogen studies with apple and cranberry the influence of diet on the quality of faecal fat in patients with and without steatorrhoea uber die unterschiediiche beeinflussung des tryptophansteffwechsels dutch vitamin b6-mangel in der ratte. hoppe-seyler's influence of vitamin b12 and its coenzyme upon incorporation in rive of amino acids into tissue proteins in rats relativer vitamin b6-mangel hei erkrankungen der schilddriise strukturanomalien der z/ihne bei vitamin d-mangel-raehitis und der vitamin d-resistenten renalen rachitis the effect of fluoride on bone effects of insulin on hepatic glucose production and utilization prevention by hydrocortisone of changes in connective tissue induced by an excess of vitamin a acid in amphibia acute hypervitaminosis a in guinea-pigs. i. : effect on acid hydrolases der einfiu~ yon vollkornbrot auf den calciumstoffwechsel bei schulkindern effect of feeding milk replacers with varying amounts of f~ for hothonsc lamb production egg yolk and serum cholesterol levels: importance of dietary cholesterol intake effect of protein intake on glutamic dehydrogenase and amino acid desruination in rive observations in experimental magnesium depletion effect of gibbercluc acid on growth, gibberellin content, and chlorophyll content of leaves of potato ~ physiological factors influencing growth, reproduction, and production of well-fed dairy heifers. i. age at first breeding. ii. feeding of diethytstilbestrol tm~ influence of diet on the development of parotid salivation and the rumen of the lamb bericht fiber den wissenschaftlichen kongreb 1963 der deutschen geseuschaft fiir erniihrung influence of variations in dietary calcium: phosphorus ratio on performance and blood constituents of calves the lack of a consistent chick growth response to norwegian kelp meal some effects of kinctin on the growth and flowering of intact green plants incorporation of [,2p] orthophosphate into phospholipids of frog tissues during feeding and stmrvation growth-modifying and antimetabolite effects of amino acids in chrysanthemum a study of techniques used by advertisers in dealing with weight control. a national health problem lipid excretion. 3.: examination of faecal lipids of rats injected intravenously with serum lipoprotcin containing ~ac-labelled cholesterol effect of diet and diabetes on plasma glucose, fatty acid, and insulin effect of cigaret smoking during pregnancy: study of 2000 cases. obstetrics gynecology 21 respiration and phosphorylation in live homogenates from rats exposed to hypoxia and food restriction the influence of mi]l~ fat depressing rations on the yield and composition of bovine milk phosphatides and cholesterol in the rat bed: effects of growth, diet, and age the effect of plant nutrients and antagonistic microorganisms on the damp. ing-off of cotton seedlings caused by rhizoctonia solani kurus l~utrition of gram-negative anaerobic bacilli. nutrition rev. 21 effects of glucose on the production by escherichia coli of hydrogen sulphide from cysteine. j. general iylierobiol. 30 enumeration of psyehrophilie microorganisms vitamin requirements of three pathogenic fungi calorie requirements of rat intestinal microorganisms specificity of the salt requirement of halobacterium cutirubrum influence of the aqueous potato extract and its fractions on growth and spore formation of the b. pumilus and the production of the antibiotic tetaine the relationship between hormonal activity and sugar metabolism in protoparce scxta (joka~sen) and blabcrus craniifer bur~ieister apparent incorporation of ammonia and amino acid carbon during growth of selected species of ruminal bacteria l~ber die wirkung anorganischer st~ube auf das wachstum yon mikroorganismen effect of dietary calcium lactate and lactic acid of faecal eseherichia coli counts in pigs uber den einflul3 des n~ihrsubstrats auf die hemmung des bakterienwachstums durch cyanid autoradiographic studies of the differential incorporation of glycine, and purine and pyrimidine ribosides by paramecium aurelia correlation between the essential amino-acid requirements of staphylococcus aureus, their phage types, and antibiotic patterns nutrition and metabolism of marine bacteria. xii.: ion activation of adenosine triphosphat~se in membranes of marine bacterial cells carbon dioxide fixation in bacillus anthracis bacterial growth under conditions of limited nutrition interrelationship between temperature and sodium chloride on growth of lactic acid bacteria isolated from meat-curing brines morphological variation and nutrition of a new monoeentric marine fungns feeding stimulants required by a polyphagons insect, schlstocera gregaria vitamin requirements of root nodule bacteria phcnotypic, genotypic, and chemical changes in starving populations of aerobacter aerogenes studies on the d-amino acids. ii.: utilization of d-amino acids by lactic acid bacteria role and formation of the acid phosphatase in yeast der einflub yon co~-partia]druck und glucose-konzentration auf wachsturn und stiekstoffbindung yon azotobacter chroococcum bei~ inorganic polyphosphate metabolism in chlorobium thiosulfatophilum effects of molybdenum, vanadium, tungsten, and cobalt on growth of rhizobia and their hosts nutrition of leptospira pomona. ii.: fatty acid requirements 9 sterilization by beta-propiolactone of solid nutrient media for eultivation of moulds the digestion of natural food protein by the elearnose skate raja eglanteria (bose.) utilization of amino acids during metabolism in escheriehia coil the effect of nutrition on the growth of fasciola hepatica in its snail host cobamide coenzyme contents of soybean nodules and nitrogen fixing bacteria in relation to physio]ogical conditions determination of carbohydrate metabolism of marine bacteria the amino acid requirements of various types of shigella mushroom culture. factors affecting the growth of morel mushroom myecelium in submerged culture lebensmittelzusatzstoffe und mutagene wirkung. vii. : priifung einiger xanthen-farbs~offe auf mutagene wirkung an escherichia coll the biological control of glycogen metabolism in agrobaeterium tumefaeiens the maintenance requirement of escheriehia coll methionine requirement for growth of a species of mieroeoecus ~iorphogenesis and nutrition in the memnionella-stachybotrys group of fungi viable organisms from feces and food-s~uffs from early antarctic expeditions the metabolism of yeas~ sporulation. v. : stimulation and inhibition of sporulation and growth by nitrogen compounds the effect of lipids on citric acid production by an aspergillns niger mutant relationship between deuterium inhibition of growth and glucose catabolism in saecharomyees cerevisiae function of trehalose in baker's yeast (saccharomyces cerevisiae). arch. biochem preparation and lyophilization of colicine suspensions. i. production of eolicines in liquid nutrient media lvber den einflub der kulturbedingungen auf die stramenempfmdliehkeit der glueoseoxydation in baeterium cadaveris nutritional requirements and metabolism of myeoplasma laid-lawil j. gen. microbiol. 30 die wirkung subletaler konzentrationen yon sorbinsi~ure auf escherichia coli und aspergillus niger the genetic analysis of carbohydrate utilization in aspergillus nidulans the amino acid nutrition of respiration deficient and respiration competent saecharomyces. a. van leewenhoek nutritional studies of some membem of mucorales. iv.: 1. sugars, amino-, and organic acids of the myceaium selektivn~hrboden fiir staphylokokken effects of certain amino acids in anthranilate production in neurospora crassa studies on the polysaccharide-fermenting lactic acid bacteria. in. : nutritional requirements and the existence of fermentation promoting factors for sucrose and inulin the catabolism of proteins and nucleic acids in starved aerobacter aerogenes aerobic fermentation and the depletion of the amino acid pool in yeast cells influence of hydrogen ion concentrations on the utilization of sodium nitrite by fungi oxidative metabolism of glucose in leaf tissues infected with tobacco mosaic virus differential effects of amino acid deficiencies on bacterial cytochemistry nutritional requirements of an aspergiuus niger mutant for citric acid production culture de tissus d'insectes ~, l'aide d'extrait d'embryon de poulet en l'absenee d' h6molymphe. c. r. acad utilization of some carbon and nitrogen sources by pseudomorms fluorescens on the selection of microorganisms for use in bacterial fertilizers in vitro and -rive uptake of carbon-14 labelled alanine and glucose by ascaridia galli, parasitic nematode of chickens growth of psychrophiles. i. : lipid changes in relation to growgh-temperature reductions vitamin requirements of listeria monoeytogenes parasitism and nutrition of gonatobo~rys simplex the effect of alkali metals on the growth of staphylococcus pyogenes the uptake of potassium and rubidium by staphylococcus pyogenes metabolism of nucleic acids and of nucleotides in the course of synchronous development of azotobacter vihelandii studies on the biotin-oleie acid requirements of a lactobaeillus plantarum variant isolated from chick feces unusual response to iron-dextran. brit. *ned. j. 1963, nr. 5331, s. 630. +in'. n.: tissue trypsin and trypsinogen levels in pancreatitis skeletal development of suckling kittens rate of liver regeneration atherogenesis in the monkey the significance of serum triglyeerides anaemia and parasitism in man physiological mechanisms in nutritionally-induced differences in ovarian activity of mature ewes bone development in suckled pigs production performance of artificiauy and non~r~ifically sired herd-mates in wisconsin search for an unidentified nutrient in mammalian liver. part i.: growth studies with various ox liver preparations proline control of the feeding reaction of cordylo-phora relationship between longevity and production in holstein-friesian cattle circadian adrenal cycle in c mice kept without food and water for a day and a half metabohc pmduc~s form labelled ethanol. iv. : disappearance of ethanol-carbon from morphological fractions and lipids of rat tissues acetate utilization by maize roots vajda, ]3. : i~c~sll-rcs of body fat and hydration in adolescent boys some characteristics of a proteolytic enzyme system of pseudomonas fluorescens some metabolic relationships between host and parasite with particular reference to the eimcriae of domestic poultry nucleotide degradation in the muscle of iced haddock (gadns aeglefinns), lemon sole (pleuronectes microcephalus), and plaice (pleuronectes platessa) effect of starvation and 6-mcthylprednisolone (m_edrol) on the acid phosphatase of rat liver and muscle metabolic patterns in preadolescent children. vii. : intake of niacin and tryptophan and excretion of niacin or tryptophan metabolites biochemical changes in fish muscle during rigor morris studies on ornithine synthesis in relation to benzoic acid excretion in the domestic fowl effect of manual total collection of feces upon nutrient digestibilities polarographie studies on storage of meats. xxii. : influence of proteolytic enzymes on the polarographie wave of beef protein solutions post-mortem changes in chilled and frozen muscle genetic-nutritional interactiions as affecting the early growth rate of chickens effect of unequal milking intervals on lactation milk, milk fat, and total solids production of cows changes with age in glutamic oxalacetic transaminase activity of sonically oscillated tureen juice compared to total steam volatile fatty acids in calves fed different roughages catecholamine metabolism and some functions of the nervous system a study of some of the conditions affecting the rate of excretion and stability of creatinine in sheep urine changes in feeding behavior after intracerebral injections in the rat kanzcrogene substanzen in wasser und boden food additives and contaminants and cancer milk allergy in infancy food poisoning due to salmonella cnteritidis vat the mineral element content of spring pasture in relation to the occurrence of grass tetany and hypomagnesaemia in dairy cows insecticide residues in meat. residues in body tissues of livestock sprayed with sevin or given sevin in the diet over de giftigheid van solanum-alkaloidcn toxic products in groundnuts zur beziehung zwischen lipidcn hepatotoxicity of foods: a consideration of the hepatotoxicity of a few phanerogams and eryptogams. their possible influence in the pathogenesis of cirrhosis and hepatoma food-poisoning potential of the enterococei vanadium. excretion, toxicity, lipid effect in man an institutional food-poisoning outbreak examination of market milk of novokuznctsk for brucellosis an outbreak of food poisoning in a mental hospital food allergy as a cause of abdominal pain radioactivity in the diet the effect of microbial contamination on the requirement of chicks for certain nutrients the acute oral toxicity of cottonseed pigment glands and intraglandular pigments sur l'absorption du edsium radioactif par rorge. c. r. hebd. s6ances aead die experimentelle alimentiire lebernekrose a]s empfindlicher indikator bei thermiseher belastung der milch. uber die magermilehtroekntmg the comparative toxicity of ethylene dibromide when fed as fumigated grain and when administered in single daily doses repository polyvalent insect antigen treatment for patients sensitive to hymenoptera. a clinical evaluation precursors of carcinogenic hydrocarbons in tobacco smoke toxin production in naturally separated liquid and solid components in preparations of heated surface-ripened cheese inoculated with clostridium botulinum allergieversuehe am tier zur ~tiologie der sogenannten margarinekrankheit. dr. reed. wschr. 14 [1963] nr. 1, s. 9/12. --, allergenwirkung oder immunologisohe adjuvanswirkung in der ~tiologie der sogenarmten margarinekrankheit radium-226 in human diet and bone miodine in the thyroids of north american deer experimental groundnut poisoning in pigs cholesterol as carcinogen safety factors in water fluoridation based on toxicology of fluorides entelo epidemiologische gegevens over her ,planta-exantheen" te rotterdam, verkregen door enquetc-onderzoek planta-~x~ntheem" epidemie te rotterdam in de m~nden ~ugnstu~ en september 1960 salmonella-verontreiniging van plantaardige grondstoffen veer voedingsmiddelen van mens en dier increase of strontium-90 and caesium-137 sodium fluoride intoxication salmonellosis in the netherlands zwei seltene salmonellenfunde untersuehungen fiber die chronisehe toxizit~t der ascorbins~ure bei der ratte captan in green vegetables rfickst~nde yon pflanzenschutzmitteln, insektiziden mid dergleichen in der nahrung und ihre bedeutung ffir die gesundheit der gehalt der milch an 181j, 1,~co ' u0ba _{_ 140la in der deutschen )iileh in der zeit yon langfristige nutritive anwendung yon antibiotika in der tierern~hrung im hinblick auf die menschliche gesundheit mi~ besonderer beriicksichtigung yon chlortetrazyklin a milk-borne outbreak of food poisoning due to salmonella heidelberg ergebnisse yon schwebversuehen an farbstoffen zur farbmattierung yon tabakwaren nutritional secondary hyperparathyroidism of the cat insecticide residues in fat. a screening method for chlorinated pesticide residues in fat without cleanup untersuehungen fiber die quantitative verteilung radioaktiver falloutprodukte in milch too many vitamins radios~ron$ium removal from milk. determination of apparent equilibrium constants of the exchange reactions of sodium, potassium, calcium, and magnesium with amberlite ir-120 ern~hrungsphysiologische eigenschaften der margarine. fette, seffen, anstrichmittel 65 smoking and cancer: retrospective studies and epidemlologieal evalution beobachtungen fiber den verlauf der alkoholkrankheit am krankengut einer heilanstalt die verschmutzung yon trinkwasser dutch i)etergentien grain fumigant residues. occurrence of bromides in the milk of cows fed sodium bromide and grain fumigated with methylbromide insecticide persistence. the disappearance of endrin residues on cabbage lebensm ittelchem u. gerichtl reproductive performance of female miniature swine ingesting strontium-90 daily toxicity of nitrate nitrogen to cattle methods of residues of phosphated insecticides and miticides in foods on bacillary excretion in food toxinfections of salmonella etiology relationships between the deposition of strontium-90 and the contamination of milk in the united kingdom staphylococci in cottage cheese is~cs and potassium in people and diet. -a study of finnish lapps effect of treatment of seeds with 2-chloroethanol on the resistance to boron toxicity in wheat seedlings desferrioxamin, eine neue das eisen bindende und eliminierende substanz zur behandlung der 9rim~rcn und sckund~ren i-i~mochromatose akuter eisenvergiftungen toxic products in groundnuts smoking, arteriosclerosis, and age the incidence of milk sensitivity and the development of allergy in infants einflul] yon fluor und jod auf den stoffwechsel, insbesondere auf die schilddrtise quelques exemples illnstrant la valour et l'utllit6 des m~thodes de lysotypie clans certaines salmonelloses humaines d'origine alimentaire food poisoning caused by panthogenic halophilic bacteria (pseudomonas enteritis txkikawa): 1%ep0rt of four autopsy cases procaine penicillin g in milk following intramuscular injections comparative subacute toxicity for rabbits of citric, fumaric, and tartaric acids distribution of pesticides in fermentation products obtained from artificially fortified grape musts mercurial fungicidal seed protectant toxic for sheep and chickens the problem of salmonella food poisoning dietary factors in the pathogenesis and treatment of cirrhosis of the liver. med. clinics of north america 47 an outbreak of salmonella food poisoning in l~ehmadabad town, kaira i)istxiet, gnjaxat 8~a~e la tossinfezionl alimentarl da salmonella nell' 0spedale maggiore di milano dal 1954 al 1961 water intoxication due to oxytocin: reporb of a case c~sium-137 und kalium in menschlichen organen und in der milch 1959/60 caesium-137 in dried milk produets in relation to phytoellmatic zones smoking and oral cancer occurrence of hepatomas in rats fed diets containing peanut meal as a major source of protein nachweis yon mangan-54 und kobalt-57 in pflanzen als fo]ge russischer kernwaffenvcrsuche e-ruhr-epidemie durch speiseeis bcricht fiber eine arbeitstagung bei der internationalen atomenergic-behsrde in wien vom 12. bis 14. i)ezember 1962. i)t. lebensmittel-rdsch the development of microbiological standards for foods. j. milk food technol a case of breslau salmoneliosis caused by eating chicken internationales rundgespr~ch fiber lebensmittelchemische probleme in wiesbaden und eltvllle a. rh. (4 vortragsreferate) staphylococcal infection of raw milk as a cause of food poisoning. monthly bull. ministry health pub carcinogenic effect of egg white, egg yolk, and lipids in mice eczema and cow's milk exitus letalis nach lebensmittelvergiftung dutch bacillus cereus repression of staphylococcus aureus by food bacteria. ii. : causes of inhibition a further report on the radioactive contamination of milk and milk products in japan. determination of strontlum-90 and cesium-137 concentrations in milk powder in japan concerning sporadic salmonelloses insecticide residues. extraction and cleanup studies for parathion residues on leafy vegetables salmonellosis epidemiology zur frage der deponierung yon nutrltiven allergenen im organismus. allergic, _~sthma 9 allergic children with various symptoms caused by cows' milk messungen der umweltsradioaktivit~t und der radioak-tivit~t yon lebensmitteln im jahre ein cxperimenteller bcitrag zur tabakrauehkanzerogenese. dr. reed. wschr. 88 [1963] nr. 13. u n. : contamination of leaves by radio active fall-out insecticide residues in milk and meat. residues in butterfat and body fat of dairy cows fed at two levels of kelthane (1.0 and 2 insecticide residues in milk. residues in milk from dairy cows fed low levels of toxaphene in their daily rations tier-und pfhnzenerniihrnug _anlrnal and plant nutrition summary of ,tropical crops soil, analysis, and its relation to plant composition and growth fertilisers and plant nutrients ulcers in swine tnfluence of chelating agents on the concentration of some nutrients for plants growing in soil under acid and under alkaline conditions nutritional evaluation of permanent pastures with dairy cattle in louisiana the herbage intake of eattle grazing lucerne and cocksfoot pastures terminology and methods for feeding and weighing animals the effect of feeding on evaporative heat loss and body temperature in zebu and jersey heifers studies on the requirements and interaction of copper and iron in broad breasted bronze turkeys to 4 weeks of age some factors affecting iron uptake by strawberry plants feed consumption during lactation and involution in sprague-dawley-rolfsmeycr rats the effect of variations in the energy and protein levels of the ration upon performance in the pig use of barley in high-efficiency broiler rations. 6. poultry sci tierarzncimittcl und aufzuchtmittel in der landwirtschaftlichen praxis. gesund. heitliche erwggungen zum schutze des konsumenten bei der anwendung yon tierarzneimitteln und aufzuchtmitteln in der landwirtschaftlichcn praxis, tell ii mechanism for movement of plant nutrients from soil and fertilizer to plant root growth rate of the tea leaf as determined by shade and nutrients. empire j. exper note on induction of flowering in ~railing shoots of clones of saccharum spontaneum effect of level and sequence of feeding and breed on ovulation rate, embryo survival, and fetal growth in the mature ewe evidence for a high zinc requirement at the onset of egg production aufnahme und wirkung des mikronghrstoffs knpfer in ionogencr und ehelatisierter form bei gerste effects of pelleting and varying grain intakes on milk yield and composition the relationship of gibberellic acid to flower initiation in column stock, math~ela incana the effect of selenium administration on the growth and health of sheep on scottish farms the horsebean (vicia faba l.) as a vegetable protein concentrate in chick diets size and feeding of different types of fishes the influence of age of chicks on their sensitivity to raw soybean oil meal influence of the mineral nutrition on the resistance of peach trees to fusicoceum amygdali de la croix granular fertilizer. influence of associated salts on plant response to dicalcium phosphate a comparison of feeding growing pigs once or twice daily the interrelation of nutrient supply, leaf nutrient content, and vegetative growth of ilcx crenata 'green island' effect of rationing grass on the growth rate of dairy heifers and on output per acre, with a note on its significance in experimental design experiments on the nutrition of the dairy heifer. iv.: protein requirements of 2-year-old heifers grass silage vs. hay for lactating dairy cows hay vs. silage for two to six months old dairy calves weaned at 25 or 60 days effects of high levels of copper and ehlortetracycline on performance of pigs seedlings resistance of corn to leaf feeding of the european corn borer ostrina nubflalis ease of hydrolysis of the hemieeiluloses of forage plants in relation to digestibility bodenkde. 100 [1963] mr. 1, s. 53/58. --caleium-mangelsymptome an h6heren pflanzen effects of frequency of feeding on urea utilization and growth charae%oristics in dairy heifers factors affecting the voluntary intake of foods by cows. 6. : a preliminary experiment with ground, pelleted hay the relationship of dietary energy level and density to the growth response of chicks to fats salt tolerances of pinus thunbergii compensatory carcass growth in steers following protein and energy restriction a guide to production, care, and use of laboratory animals. federation prec. 22 estimation of essential fatty acid intake in swine automatic dispensing at frequent regular intervals of liquid diet for piglets chelation in nutrition. chelates and the trace element nutrition of corn der einflul3 yon humuss~ure auf wachstum und ver~inderungen des freien zuekergehaltes bci winterweizenpflanzen, die im dtmkeln kultiviert wurden a comparison of the growth of chicks in the gustafsson germ-free apparatus and in a conventional environment, with and without dietary supplements of penicillin an evaluation of weed competition and the effects of weed extracts and leachates on the development of field corn (zea mays l.) and oats (arena sativa l digestibility of rations containing different sources of supplementary protein by young pigs the effects of urea supplements on the utillzation of straw plus molasses diets by sheep production performance of artificially and nonartifieiallysired herd-mates inwiseonsin dietary phosphorus for laying hens tolerance to acid soil conditions in barley effect of calcium and magnesium upon digestibility of a ration containing corn oil by lambs effects of caloric restriction during the growing period on the performance of egg-type replacement stock untersuchungen fiber die verwertung yon calcium-und phosphorsalzen aus fisehgr~itenmehl einigcr frischfische und fischkonserven bei der verffitt~rung a nut~rient requirement for optimum water absorption by intact root systems preparation of feed for animal nutrition experiments responses of winter wheat to nitrogen and soil nitrogen status studies on calcium requirements of broilers znm problem dcr nahrungspflanzenwabl der aphiden some factors affecting leaf development and longevity and the subsequent yield of corn grain efficiency of energy utilization by young cattle ingesting diets of hay, silage, and hay supplemented with lactic acid the effects of a plant steroid on body weight and feed efficiency of broilers feeding troughs for guinea-pigs beitrag zur ]~ackfruchtmast mit schweinen unter besondercr beriicksichtigung des n~hrstoffgehaltes der beifuttermischungen und der the feeding of thyroprotein to lactating sows zur planung, durchfiihrnng und auswertung yon schweinemastvcrsuchen bei gruppenfiitterung the influence of barbituric acid derivatives on the development of plant roots and root hairs factors affecting the voluntary intake of food by cows. 5.: the relationship between the voluntary intake of food, the amount of digesta in the retieulo-rumen, and the rate of disappearance of digesta from the alimentary tract with diets of hay, dried grass or concentrates artificial food for oak-silkworm raising the comparative toxicity of ethylene dibromide when fed as fumigated grain and when administered in 8ingle daily do~0~ gibberellin at the vineyard oak wilt development and its reduction by growth regulators. i. production and activity of oak wilt fungus pectinase, ecmulase, and auxin. ii. effect of halogenated benzoic acids on oak trees, the oak wilt diseases, and the oak wilt fungus regulating nutrient intake in laying hens with diets fed ad libitum some effects of different soils on composition and growth of sugar beet production of fodder yeast from barley. i. preliminary studies on the use of the waldhof fermenter development and nutrition of new species of thranstochytrium studies on the effect of frequency of feeding upon the biology of a rabbit-adapted strain of pediculns humanus the influence of previous vitamin k nutrition on thromboplastie activity of brain extract the effect of nutrition conditions on the growth of and nitrogen accumulation by fodder beans when sown together with indian corn. i)oklady akad. nauk sssr dutch phenylbors~ure induzierte fragen der resistenzsteigerung in der modernen gefliigelhaltung chelation in nutrition. metal chelates in plant nutrition beziehungen zwischen dcm kupfergehalt und dem zeitlichen auftreten yon kupfermangelsymptomen an hafer in wasserkultur mit kleincn bodenmengen increased tolerance of bean plants to soil drought by means of growth-retarding substances effect of monocaleium and diammonium phosphates on crop yield, and their influence on soil solution movement and characteristics when associated with different salts effect of barbituric acid and ehlortetraeyeline upon growth, ammonia concentration, and urease activity in the gastrointestinal tract of chicks effects of feeding low levels of dimethoate on milk and on whole blood cholinesterase activity of dairy cattle die ziichtung von fleischschweinen und die folgeerscheinungen, die sich besenders im hinblick auf die qualit~t yon fleiseh und fett ergeben the relationship of specific nutrient deficiencies to antibody response in swine. i.: vitamin a. ii.: pantothenie acid, pyridoxine or riboflavin further studies of diet composition on egg weight effect of various levels of fluorine, stilbestrol, and oxytetraeycline, in the fattening ration of lambs studies on the properties of l~ew zealand butterfat. viii. the fatty acid composition of the milk fat of cows grazing on ryegrass at two stages of maturity and the composition of the ryegrass lipids soil potassium and the growth of vegetable seedlings artificial feed for silkworm, bombyx mori some effects of feeding stilbestrol, ehlortetracyeline, and penicillin with alfalfa soflage on steer performance and carcass quality food agric. 14 [1963] nr. 2, s. 66/75. --, mineral supplements for sheep the influence of higher volatile fatty acids on the intake of urea-supplemented low quality cereal hay by sheep untersuehungen fiber den umsatz waehsender sehweine ab geburt. 2. mitt growth of edible emorophyllous plant tissues in vitro chelates in agriculture. metal chelation by glucose-ammonia derivatives economic analysis of high-level grain feeding for dairy cows evaluation of the dacron bag technique as a method for measuring cellulose digestibility and rate of forage digestion n~ihrlssungen fiir zuckerriiben in wasser-und sandkultur activity of gibbereuin:'d' on the germination of photosensitive lettuce seeds raw and heat-treated soybeans for growing-finishing swine, and their effect on fat firmness ration effects on tureen acids, ketogenesis, and milk composition. i.: unrestricted roughage feeding a new growth stimulant, ~ growth hormone the effects of specific viruses, virus complexes, and nitrogen nutrition on the growth, flowering, and mineral composition of strawberry plants peculiar feature of respiration and redox processes in the rice plants grown under different nutritional conditions einflul] der silagefiitterung auf die qualit~t yon milch und milchprodukten. 3. mitt. : einflul] der silagcfiitterung auf die organoleptischen eigenschaften dcr milch effect of grinding and pelleting on the utilization of coastel bermuda grass hay by dairy heifers langfristige nutritive anwendung yon antibiotika in der tierernlihrung im hinblick auf die menschliche gemmdheit mit besonderer beriicksichtigung yon chlor-te~azyklin mode of action of growth retarding chemicals yield of sugarcane in louis-ana as influenced by soil moisture status and climate diss effect of auxin on the emergence of lateral roots in p. mungo seedlings compound mouse diets a semipurified caries-test diet for rats present status of feeding antibiotics to htctating dairy cows effect of sodium bicarbonate in the drinking water of ruminants on the digestibility of a pelleted complete ration semi-purified diets for sheep effect of vacuum-drying, freeze-drying, and storage environment on the viability of pea pollen. ii. : effect of boron, sucrose, and agar on the germination of pea pollen hshe und zeitpunkt der diingung yon sommerweizen mit chlorcholinchlorid zur verkiirzung der halml~nge nutritional signifieance of soluble nitrogen in dietary proteins for ruminants primary signs of nutritional deficiencies of laboratory animals ]~ffe[~b of dlctary pro~in and fat on growth, protein utilization, and carcass composition of pigs fed purified diets trans-fetts~iuregehalt yon schweineschmalz nach fiitterung yon sehweinen mit rindertalghaltigem kraftfutter. (ein beitrag zur quantitativen infrarotspektroskopischen bestimmung yon trans-fetts~uren in fetten effect of liming and potassium fertilization on soil solution and on yield and composition of alfaffa and orchard grass mixtures effects of feeding various milo, corn, and protein levels on laying performance of egg production stock effect of gibberellie acid on flowering of apple trees the effects of dietary fat and energy ]evels on the performance of caged laying birds effect of age on the response of chickens to dietary protein and fat chemical control of flowering. concentration of a floral-inducing entity from plant extracts strontium-90 and calcium in milk of miniature swine studies on the properties of newzealand butterfat. vii. effect of the stage of maturity of ryegrass fed to cows on the characteristics of butterfat and its carotene and vitamin a contents new radioactive tests show how termites feed mechanisms regulating the feeding rate of daphni~ magna straus influence of low protein rations on growth and semen characteristics of young beef bulls a study of zinc deficiency in the dairy call effects of different levels of zinc and phosphorus on the growth of subterranean clover (trifolium subterraneum l.). australian j. agrie absorption, translocation, exudation, and metabolism of plant growth-regulating substances in relation to residues the effect of the performance of growing pigs of the level of meal fed in conjunction with an unrestricted supply of whey increase in yield of legumes by fer~iliser mixture with lime chemically defined medium for growth of animal cells in suspension dis sieherung der eiweiljwrsotgung in dor l~ndwirt influences of previous calcium and phosphorns intake and plant phosphorus on the requirement of developing turkeys for calcium and phosphorus relationship between isotopicauy exchangeable calcium and absorption by plants effect of adding buffers to all-concentrate rations on fcedlot performance of steers, ration digestibility, and intrarumen environment lysine supplementation of corn -and barley-base diets for growing-finishing swine the effect of gibbereliin on the germination of seeds of arboreal plants effect of physical state of coastal bermuda grass hay on passage through digestive tract of dairy heifers nitrate reduction and carotene stability. effect of nitrate and some of its reduction products on carotene stability, d. agric. food chem chemical preparations for plant protection untersuchungen fiber die ksrperzusammensetzung und den stoffansatz waehsender mastschweine und ihre beeinflussung dutch die erniihrung. 3. mitt the cobalt requirement of sub-~erranean clover in the field comparing mile and corn in broiler diets on an equivalent nutrient intake basis effect of mineral nutrition on the invasion and response of turnip tissue to plasmodiophora brassicae wor the relation of chlorogenic acid and total free phenols in potato plants to resistance to infection by verfieillium alboafxum nitrogen and potassium as variables influencing soluble nitrogen and organic acid accumulation in soybean (glyoine max). di~s. abstr. 23 bett~r british beef and barley feed. veter effect of nitrogen fertilization upon yield and digestibility of aftermath timothy forages fed to dairy heifers ration effects on dltlot steer feeding patterns effects on zea mays seedlings of a strontium replacement for calcium in nutrient media evaluation of albumen quality in a poultry breeding program nutritional studies with the guinea-pig. viii. : effect of different proteins, with and without amino acid supplements, on growth some effects of heredity and environment on appetite in dairy animals further studics on manganese nutrition of tobacco in relation to virus infection and synthesis amillo acid supplementation of pig diets chelation as a basic biological mechanism der einflu~ der stiekstoffdiingung auf die znsammensetzung yon kartoffeleiweiil z studies on photosynthesis. i. : biosynthesis of sucrose from glycolate. par~ ii. : bicarbonate utilization by washed algae production, interior egg quality, and some physiological effects of feeding raw soybean meal to laying hens alteration of post-mortem changes in porcine muscle by preslaughter heat treatment and diet modification chelation in nutrition. soft microorganisms and soil chelation. the pedogenie action of lichens and lichen acids die ergiinzungswirkung yon dl-•ethionin allein oder in kombination mit l-lysin beim wachsenden schwein untersuchungen iibcr den einflub unterschiedlicher wasservemorgung auf ertr~ge, gehalte an ~therischem 01, trenspirationsquotienten, biattgrsl~en und relative ~)ldriisendichtsn bei einigen arten aus der familie der labiaten. 2. teil gehalte an iitherischem 01, transpirationsquotienten, blattgrsflen und relative 01-driisendichten bei einigen arten aus dcr familie der labiaten. iii.: blattgrsflen, relative 01driisendichten, anzahl am haupttricb inseriertcr blattpaare und internodien. liingen cadmium: uptake by vegetables from supcrphosphate in soil studies on the protein and methionine requirements of young bobwhite quail and young ringnecked pheasants chelation in nutrition. evidence for natural chelates which aid in the utilization of zinc by chicks selective fertilization of apple-trees some soils and fertilizer relationships of the cavendish banana (muss cavendlshl lambert) on three different soils in costa rice soil organic phosphorus and the phosphorus nutrition of plants the effect of heat treatment on the nutritive value of milk for the young calf. 5. : a comparison of spray-dried skim milks prepared with different preheating treatments and roller.dried skim milk, and the effect of chlortetracyclinc supplementation of the spray-dried skim milks the effect of heat, ~reatmen~ on the nutritive value of milk for the young calf. 6. :the effect of the addition of calcium a biological assay for metabolizable energy in poultry feed ingredients together with findings which demonstrate some of the problems associated with the evaluation of fats feed additives in livestock rations: part i. : urea in dairy rations. part.i/: use of thyroprotein in cattle nutrition diet and histamine in the ruminant synthetic ion-exchange resins as a medium for plant growth nutrition of vibrio fetus theoretical basis of unicellula algae cultivation amino acid supplementation of barley diets for growing swine some effects of 2.4-dichiorophen-oxyacetic acid on swect corn (zea ]~ays rugosa l.) with emphasis on yield, tillering, root development, and exudation of electrolytes from roots and stems. i)iss. abstr feeding and management of broiler strain breeder hens relationships among seven elements in the nutrition of corn in sand culture an external effect of inorganic nitrogen on nodulation influence of enzyme supplements in lamb fattening rations gravenstein and jonathan apples produced with giberellle acid the role of carotene in the dairy cow. wiss. ver6ff. dr. ges. ern~hrung 9 vitamin a-wirksamkeit der carotine bei versehiedenen tierarten. wiss. ver-5ff. dt. ges. eru~hrung 9 upgrading the indigenous poultry of uganda. i. : the growth rates and feed conversion from hatching to maturity of indigenous poultry crossed with four imported breeds effect of different kinds of litter on growth and feed efficiency in chick rearing investigation of the mineral nutrition of datura innoxia the effect of flooding in the availability of phosphorus and on the growth of rice nutrition of the boll weevil larva ascorbic acid in the nutrition of plant-feeding insects effects on the s~maeh worm, i-iaemonehus contortus, of feeding lambs natural versus semipuriiicd diets yield and foliar composition of corn as affected by fertilizer rates and environmental factors. i)iss. abstr. 2~ [1963] nr praktische erfahrm]gen in der carotinoidversorgung yon vsgeln effect of protein-energy relationship on the performance and carcass quality of growing swine the use of quarter samples in the assessment of the effects of feeding treatments on milk composition * calcium and phosphorus requirements of finishing broilers using phosphorus sources of low and high availability amino acid supplementation of peanut meal diets for broiler chicks the effects of feeding various levels of vitamin a on chicks with cecal coccidiosis chelation in nutrition. review of chelation in plant nutrition water use by irrigated arabia coffee in the failure of certain dietary ingredients to affect the incidence of blood spots in chicken eggs dcr einflul~ der anbauverh~ltnisse auf die eigensehaften der kartoffelknolle und der st~rke effect of feeding milk replacers with varying amounts of fat for hothouse lamb production l~hysiologieal factors influeneelng growth, reproduction, and production of wcll-fed dairy heifers. i. ago at first breeding. ii. feeding of diethylstflbestrol results of an experiment ot rothamsted testing farmyard manure and n, p, and k fertilizers on five arable crops. i. : yields results of an experiment at rothamsted testing farmyard manure and n, p, and k fertilizers on five arable crops. ii.: nutrients removed by crops 9 the utilization of carotenoids by the hen and chick some effects of potassium and lime on the relation between phosphorus in soil and plant, with particular reference to glasshouse tomatoes, carnations, and winter lettuce the lack of a consistent chick growth response to norwegian kelp meal further studies on protein and energy requirements of chicks selected for high and low body weight some effects of kinetin on the growth and flowering of intact green plants individual feed consumption of turkey breeder hens and the correlation of feed intake, bocly weight, and egg production crop analysis technique for studying the food habits and preferences of chickens on range supplemental value of turkey protein for wheat herbicides and plant growth regulators preparation of purified ration for chick. parg iv. : preparation of crystalline amino acid diet evaluation of algae as a food for human diets the influence of milk fat depressing rations on the yield and composition of bovine milk the effect of plant nutrients and antagonistic microorganisms on the damping-off of cotton seedlings caused by rhizoetonia solani kukn ki;-;sehe ern~ihrung und di~tetlk clinical nutrition and dietetics a statement approved by the board of directors of the canadian heath foundation radioactivity and human diet probleme der ern~hrung durch gefrierkost. sympomum der d0utschen gcgell~ehaft ffir ernghrung veto 14. bis 15. mgrz klinische ernghrungslehre" und wissenschaftlicher kongreb der deutschen gesellschaft flit ern~hrung an der johannes-gutenberg-universit~t mainz veto 17. bis 19 wissenschaftlicher kongreb der deutsehen gesellschaft ftir ern~hrung an der johannes-gutenberg-universit~t mainz am 18. und 19 ernghrung nnd digit" 12. deutseher kongreb ffir ~irztliehe fortbildung in berlin veto 5. bis 9 arbeitstagung fiber klinisebe ernghrungslehre. ern~ foods of the future (forts.). problems in space foods and nutrition. foods for extended space travel and habitation the question of fats. ii.: fats and disease behandlung fettbedingter gerinnungsstgrungen mit lipostabil sugar and dental caries obesity and sugar addiction hunger and malnutrition lancet 2 nutrition and general practice bericht fiber die vortragstagung des fachverbandes lebensmittelchemie der chemischen gesellschaft in der ddr vom 19 arbeitstagung fiber kommission ffir volksern~hrung, lebensmittelgesetzgebung und -kontrolle (eek) zu yi~inden des eidg the national diet-heart study low fat diet in familial mediterranean fever the thyroid gland in infant malnutrition evaluation of fao amino acid reference pattern studies on the physiology of nutrition in surinam rickets in southern israel diet and heart disease maiskeims1 in ernt~hrung und ditltetik apha conference report safe and nutritious food supply malnutrition and disease expert committee on medical assessment of nutritional status protein malnutrition the fat tolerance curves of patients with hyperllpidcmia and athcrosclcrosis die lactose im rahmen der ernt~hrung effect of environment on nutritional status zur theorie und praxis der zuckerkrankheit. wiener z dietetically induced experimental flous of rats physikalisch-diiitetische therapie yon hautkrankheiten. arch. phys. therapie 15 err~hrungsforschung 7 [1962/63] :nr. 4, s. 598/ 612. +bo rtiw~l, p. w. : milk-borne disease consumers' reactions to instand foods de voeding van woonwagenbcwoners experimental investigations on nutrition and human behavior. a post-script. amer di~tetische therapie der chronischen herzinsuffizienz construction and validation of the food attitude scale why we have a safe and wholesome food supply use of food in a psychiatric setting stature and nutrition in cystinuria and hartnup disease ])as endokrinologisehe syndrom des proteinmangels urinary excretion of 3.4-dlhydroxyphenylalanine (dopa) in two children of short stature with malnutrition current problems affecting consumption of milk and indnstry's response to them preparedness for emergency feeding fluoridation and public relations dieetprodukten in vlaanderen incorporation of labelled glycine into erythrocyto glutathione of rabbits; effect of nutritional muscular dystrophy hot wcreldvoedselvraagstuk sniker -glycogcen -tandbederf dietary in take in patients with arthritis and other chronic diseases a clinical trial of iron-fortified bread effects of freater intake of milk, fruits, and vegetables joint fao/w/to expert committee on nutrition" fiber eine sitzung in genf vom 18. his 25 serum cholesterol in a military population. its relation to obesity and the military diet ). ~z~, a. c. 9 some nutritional problems of older age groups neuere biochemisehe untersuchungen zur diagnostik und therapie yon b-vitamin-mangelzust~nden call-harvard nutrition project. iii.: the erythroid atrophy of severe protein deficiency in monkeys cali-harvard nutrition projeet. ii. : the erythroid a~rophy of kwashiorkor and marasmus zur hshe des erwiinsehten fottverbrauehs ern~hrung des sportlers voeding 24 moderne ern~hrungsbedarfsnormen. i. mitt. z. ges. hyg. 9 [1963] nr. 1, s. 11122. *--~ioderne ern~hrungsbedarfsnormen. 2. mit~.: z. ges. hyg. 9 a comprehensive home-care program for the chronically ill fat-modified foods for serum cholesterol reduction besonderheiten der ern~hrung alter menschen chronic malnutrition in turkey. v. studies on serum fatty acids in malnourished children prevention of ,meat anemia" in mice by copper and calcium beeinflussung der sportlichen leistungsfdhigkeit dutch eine geeignete er-n~ihrung physiology of adolescence. ii, l~u-trition -basal oxygen consumption -energy expenditure and balance -nitrogen metabolism -calcium metabolism -iron metabolism -red cell mass and hemoglobin ern~hrungsproblemc bei chirurgisehcn kranken. wiss. versff. dr. ges. ern~hrung 11 moderne vitamin b~-therapie: oral, rektal oder parenteral ? a palatable diet for producing experimental folate deficiency in man smoking in hospital was ist hungern und was heibt the cultivation of tflapia. this prolific fish as a fine source of proteinrich food in underdeveloped areas pyridoxine supplementation during pregnancy. clinical and laboratory observations on japanese foods nutritional sequelae of ga~trio surgery koehsalzarme kost und nierenerkrankungen theoretische und praktische grundiagen der ernilhrung in der fett in der diabeteskost foods or supplements? g zur hygiene und ,di~tetik des rauehens zur dis behandlung der uremic anaphylactie shock of the lungs triggered by mieroaspiration of cows' milk: a form of sudden unexpected death in early infancy the food service industry and its relation to the control of foodborne illness die konservative therapie des peptischen gesehwiirs gezondheid op reis addictive aspeeta in heavy cigarette smoking die ern~hrung im rahmen de~ heilvers im kurort the diet in renal faiiure is the rationale for gaetrointestinal diet therapy sound? familie-beruf-ern~hrung die dfiitbehandiung der leberkrankheiten. i)t. reed vom hunger his zum ~beritul3-weltweite ern~hrungsprobleme die bedeutung der vitamine in der t~tglichen erniihrung s~ure-und baseniibersehiissige naln'ung. therapiewoehe 13 [1963] nr. 13, s. 563/565. --ss und chronische acidogene und alkalogene erns z. em~hrungswiss industrial lunches and public health the assessment of nutritional status in man: chairman's opening remarks therapie der essentiellen hypertonie speeifieke voedings-en voorlichtingsproblemen in tropische landen wie kann man unsere kos~ und unsere kostgewohnheiten beeinflussen? neue konzeptionen in der wasser-und salzsubstitution some aspects of the relation of nutrition and pregnancy is coronary heart disease preventable? world hunger demineralization of whey. use of its protein in infant feeding elaidinized olive oil and cholesterol atherosclerosis soziatrischo aspekte dee genul)-und arz~aeimittelkonsums verwendung yon htilsenfriichten in der diabetiker-di~t sanitation and dishes sanitation and dishes. aspects old and new. part ii smoking, arteriosclerosis, and age neue weg~ zur erni~hrungsphysiologi~chen aufwertung yon getreide-erzeugnissen diphyliobothrium latum and human nutrition, with particular reference to vitamin bli deficiency milk and diverticulosis dietary factors in the pathogenesis and treatment of cirrhosis of the liver. ivied. clinies north america 47 zur frage der quanti~tiven charakteristik der ern~hrung der berufst probleme der gemeinschaftsverpflegung aus der sieht des ern~hrungsphysio-logen gegevens over vitamine b,-deficientie, -behoefte en -voorziening use of government-donated foods in a rural community fluoride, teeth, and the analyst eiweil3bedarfsnormen im rahmen unserer ern~hrungsrichts~tze physiologic discomforts in 1962 navy protective shelter tests di~tvorschl~ige : akute nierenentziindtmg siii]waren und karies in theorie und praxis ernehrtmgsberatung im krankenhaus use of a low-sodium formula as an improved karell diet, with emphasis upon the outpatient management of heart failure and lymphedema pflanzliches eiweil~ fiir die erniihrung des menschen influence of diet on viral hepatitis influence of siblings on student smoking patterns voeding yon leerlingen van een lagere technische school. ii. calorie~n-en nutri~ntenwaarde early use of circulating blood volume, weights, and normal diet in acute renal failure fette in tier nahrung. dr. recd. wschr. 14 [1963] nr. 9, s. 247/250. *scm~-idt-b~bach, a.: ~j~ber die di~tetik der sauermilch begriff und anfgabe di~tetischer lebensmittel zur ursache yon geschmackskalamit~ten in trinkwassertalsperren psychologische motive im wandel des brotverzehrs improving levels of nutrition through better food practices the vitamin b~ deficiency syndrome in hun~n infancy. biochemical and clinical observations treatmen~ of ,refractory obesry" with ,formula die~ nr. 1, s. 66ff. (45 s.). 3elwzea, c. c.: morphologie constitution and smoking prediction the outcome for obese dieters symposium fiber probleme der ern~hrung durch gefrierkost in karlsruhe yore 18 coordination of long-term care of :pku children die di~t bei diabetes meuitus a nutritional supplement (nutrament) for elderly patients dietary intake of five groups of subjects. 24-hr. recall diets vs. dietary patterns the prolonged effects of a low cholesterol, high carbohydrate diet upon the serum lipids in diabetic patients stand und perspektiven der eiwei~versorgung. zur zielsetzung des verhandiungsthemas de voeding van rijswerkers signification des standards calorieo-azotes utilists en france erg~nzungen veto standpunkt des lebensmittelehemikers zu (dem beitrag) official acceptance of homogenized milk in the united states advances in nutrition and dietetics nutrition of 96 naval recruits during a shelter habitability study hot ombuigen van voedingsgewoonten de voeding van schippemkinderen san boord en in de internaten voeding 24 [1963] iqr. 5, s. 291/308. --le traitement de rinsuffisance rtnale her zoutarme-eiwitarme dicer ein beitrag zur allgemeinen el3problematik, ausgehend yon einer anorexia nervosa rroblem~ in nutrltlon~l supplementation an4 ~mri~hnl~ut detection of nutritional imbalances theorie und praxis der schwangerenern~hrung die pharmakologisehe beeinflussung yon hunger mad s~ttigung problems in the evalutaion of nutritional status in chronic illness europ~ische di~ttagung in amstercl~m (17. bls 19 entwieklung des brot-und gctreidevcrzehrs in der neuercn zeit nutrition and palatability coehac dis~tse. -biochemical and technological aspects die di~itetik der :fettsucht kinderemll}~mg nutrition of infants and children report on infant feeding childhood nutrition in lapland. :nutrition rev the thyroid gland in infant malnutrition. nutrition rev. 21 [1963] nr. 1, s. 32. +n. n.: physical activity of obese girls appraisal of nutritional adequacy of infant formulas used as cow milk substitutes isomaltose intolerance causing decreased ability to utilize dietary starch passagere hypereh]or~mische azidose bei zwei ausgetragenen s~uglingen wghrend s~uremflch-em~hrung ober erfahrungen in der frfihgeborenonaufzucht mit einer neuen bedarfsangepa6ten friilmahrung nutritional defects in adolescence g p 27 intravenous glucose tolerance in the normal newborn infant: the effects of a double dose of glucose and insulin ! attitudes towards physical ac. tivity, food, and family in obese and nonobese adolescent girls urinary excretion of 3.4-dihydroxyphenylalanine (dopa) in two children of short stature with malnutrition high salt content of western infant's diet: possible relationship ~o hypertension in the adult vitamin e to premature infants des enzym yon ~'leming (lysozym) und seine bedeutung flit die si~ugllngsern~ihrung. ann investigation on the relation of between-meal eating and dental caries of sixth-year molars in school children studies in infantile malnutrition. i.: nature of the problem in peru chronic malnutrition in turkey. v. studies on serum fatty acids in malnourished children emi~hrnng mad faekalc lysozymaktivitiit beim s~iugiing role of linoleio acid in infant nutrition factors related to the eating behavior and dietary adequacy of girls 12 to 14 years of age. dies. abstr. 23 des vitamin c im jugendalter. ii. mitt.: uber die wirkung yon natiirlichem und synthctisehemvitamin c bei l~ngeren zugaben the incidence of protein-calorie malnutrition of early childhood ein besonderer znsammenhang zwischen dem bedarf an nahrungsfett und dem stoffwechsel in den ersten lebensjahren the effect of supplements of groundnut flour or groundnut prorein isolate fortified with calcium salts and vitamins or of skim-milk powder on the digestibility coefficient, biological value, and net utilization of the proteins of poor indian diets given to undernourished children lysine fortifications of wheat bread fed to haitian school children lrber den 24-stunden-rhythmus der kalorienerzeugung bei friihgeborenen beitriige zur frage der spezifisch-dyrmmi~ehen wlrkung auf grund yon glykokoll-belastungen bei friihgeborenen. acta paediatriea acad carotine in tier stiuglingserni~hrung. wiss. versff. d$. ges. ernkhrung 9 liver and depot lipids in children on normal and high carbohydrate diets response of rural guatemalan indian children with hypocholesterolemia to increased crystalline cholesterol intake feeding value of soy milks for premature infants early feeding and birth difficulties in childhood schizophrenia. a brief study zusammenh~nge zwischen stoffwechsel und fl~issigkeitsbedarf beim s~ug-ling kuhmilchauergie beim s~ugling und ,cot death". die unspezifische kumulative sensibilisicrung malnutrition and the health of children practical aspects of infant feeding breast-feeding, weaning, ~nd acculturation appetithemmer in der ]~ehandlung der fettsucht bei kindern. miinchener med the effect of different amounts of vitamin d on growth and serum levels of calcium, inorganic phosphorus, and alkaline phosphatase in premature infants partition of urinary nitrogen in children with kwashiorkor treated with animal and vegetable proteins der einflud yon voukornbrot auf den caleiumstoffweehsel bei schulkindern ist eine rektale vitamin blz-behandlung vertretbar? dr ethyl alcohol in the pathogenesis of gout c|e~rance of infused fat emulsion in diabetic dogs praktische durehffihrung der parentcralon ern~hrung die parcntcrale ern~hrung chirurgischor paticntcn. wiss. ver6ff. dr. ges. em~hrung 11 verwertung intravenss verabfolgter aminos~,urengemische. wiss. versff. dr. ges die erkcnnung yon fe~-transportstsrungen und ihre bedeutung ftir die intra-ven6se fettzufuhr intravenous glucose tolerance in the normal newborn infant: the effect of a double dose of glucose and insulin new intravenous fat emulsion indikationen und kontraindikationen der intraven5sen fettzufuhr in der chirurgie anwendung intraven6s gegebener aminos~urengemische in dcr p~diatrie ymtravensse fettinfusionen. wiss. versff. dt. ges. ern~rung ~qotwendigkcit und erfolge der parenteralen mad sonder-ern~hrung moderne vitamin blz-therapie: oral, rektal oder p~renteral? mcd anwendung intravenss gegebener aminos~urengemische in der gyn~kologie und geburt~hilfe aminos~ureninfusionen. schweiz. reed. wsehr. 93 klinische anwendung mad erfahrungen bei der verabreiehung intravensser fettemulsionen an ehirurgischen patienten diskussionsbemerkung zum thema: die parenteralo ern~hrung ~tude exp~rimentale de la tolerance d'une solution de graisse vsgstale d'administration intraveineuse ern~hrungsphysiologische grundlagen der parenteralen ern~hrung erfahrungen mit der parenteralen ern~hrung mittels fettinfusionen. helvetica chirurgica aeta 30 nitrogen, lipid, glycogen, and deoxyribonucleic acid content of human liver. the effec~ of brief starvation and intravenous administration of glucose techn~ und indikationen der parenteralen ern~hrung des neugeborenen die praktische organisation der klinisehen infusionstherapie mit zuckerund elektrolytlt)sungen. l ~ed untersuchungen und bcobachtungen fiber intravensse fettinfusionen in der inneren klinik. wiss. versff. d$. ges. ern~hrung 11 l'alimentation parenttrale, 6mulsions lipidiques. (a suivre) ann intravcnsse ern~hrungstherapie mit fettemulsionen parenteral-und sondeneru~hrte patienten zur rekt~len kaliumsubstitufion parenteraie ern~hrtmg mit fettemulsionen konservierung mad zubereitung yon lebens-und futtermitteln nutritional hygiene, preservation and preparation of foodstuffs and feeds n. n.: vortragsveranstaltung ,fleischhygieno" der th seminar on the use of radioisotopes in nutrition science and of ionising radiation in food technology. strasbourg, 1st -6th october progress of food irradia~on work and programmes in o.e.c.d. member countries (16 berichte) safe heat processing of canned cured meats with regard to bacterial spores the role of food science i and technology on the freeze dehydration of foods public health aspects of handling animal products in the txopics fack)rs affecting bacfcrial spoilage of animal products at elevated temperatures. food technol sterilized concentrated millr. food teehnol. 17 [1963] nr. 6, s. 43/44, 49. n.n.: foods of the future. now opportunities for flavor modification unrestricted approval for irradiated bacon 3-a sanitary standards for multiple-use rubber and rubber-like materials used as product contact surfaces in dairy equipment 3-a sanitary standards for batch and continuous freezers for ice cream, ices, and similarly-frozen dairy foods bericht fiber die vortrag~tagung des fachverbandes lebensmittelchemio der chemischen gesellsch~ft in der ddr vom 19. bis 21 lebensmittelchem. u. geriehtl. chem. 17 fluoridation in great britain die enzymatische phycinspaltung in geschrotetem getreide in abh~ingigkeit yon der relativen lufffeuchtigkeit the effect of certain antioxidants during freezer storage of pork chops and sausage the mechanics of treating hatching eggs for disease prevention beitrag zur sfil~gerinnung yon kakaotrunk jodophore als desinfektionsmittel in der milchwirtschaft. milchwissenschaft 17 [1962] nr. 9, s. 513ff. (? s.). zitat: dr. lebensmittel tierarzneimittel und anfzuchtmittcl in der landwirtschaftllehen praxis. gesundheitliche erwrgungen znm sehutze des konsumenten bei der anwendung yon tierarzneimitteln und aufzuchtmitteln in der landwirtschaftlichen praxis n~ihrwertminderung dureh zubereitung dcr nahrung suue modifieazioni della flora mierobiea dei mollusohi eduli par effetto di eonservazione impropria verlinderungen des inhaltes yon dosenkonserven w~hrend lgngerer lagerung digtbrote aus der sieht ihrer praktischen gestmtung. wiss. versff. dr. ges. ern~hrung l0 erniihrungshygienische untersuchungen in kindergarten an budapester kindern im alter yon 1 bis 3 jahren. z. ges. hyg. 9 die eignung der bakteriologischen untersuehung yon kannenmilchproben als grundlage eines eutergesundheitsdienstes adequacy of cooking procedures for the destruction of salmonellae zur revitaminierung des mehles bzw. brotes. wiss. versff. dr. ges. er-n~hrung 10 conventionele verwarningsmethoden beitrag zur kenntnis der wechselwirkungen zwischen proteinen und poly. phenolcn der kakaobohnen wtihrend der fermentation nihydrazone feed medication ag~ins~ ar~iiieiaily induced escheriehia eoli air-sac infection foam-mat dried orange juice. i. time-temperature drying studies lebensmittelhygicnische probleme bei der herstellung yon gemeinschaftsverflpegung. 5. mitt. : z. ges. hyg. 9 lebensmittelhygienische probleme bci der herstellung yon gemeinschaftsverpflegung. 6. mitt.: z. ges. ttyg. 9 untersuchungen fiber die temperaturvorg~nge im innern yon lebensmittein w~hrend ihrer thermischen zubereitung, erl~uter~ am kochen yon kartoffelklsl~en. z. ges. hyg. 9 zur gewinnung yon niederverestertem pektin aus toehnisehen apfelpektinextrakten mit ammoniak: einflul] der entesterungsbedingungen auf das geliervermsgen hygienisohe beurteilung einer dutch clostridlum verursaehten massen. lebensmittelvergiftung [ungar neuartige teehnik der lebensmlttelverpaekung filr ge. schmaeks-aromastoffe und andere artikel bei ~berdruek studies with a natural source of xanthophylls for the pigmentation of egg yolks and skin of poultry die problematik der tuberkulosebeurteilung in der sehlachttier-und fleischuntersuchung freezing rate of beef as affected by moisture, fat, and wrapping materials ~ber mit komblnier~en konservierungsmitteln hergestellte konfitiiren und consumers' reactions to instant foods. food teclmol effect of supplementing lime-~reated corn with different levels of lysine, tryptophane, and isoleueine on the nitrogen retention of young children effect of freezing on autoxidation of oxymyoglobin solutions the control of gloecsporium album rot of stored apples by orchard sprays which reduce sporulation of wood infections bakteriologische befunde bei der spelseeisuntersuchung im sommer the microbiology of vacuum packed sliced bacon the stability of canned foods in long4erm storage the effect of proofing and baling on concentrations of organic acids, carbonyl compounds, and alcohols in bread doughs prepared from pre-ferments nutrients in raw vs. cooked globe artichokes effect of gamma-radiation, chemical, and packaging treatments on refrigerated life of strawberries and sweet cherries. food teehnol beeinflussung der wirkung yon kaffeeinhaltsstoffen dutch be-s~immte behandiungsverfahren der l~hbohne. (eine tierexperimentell-toxikologische studie influence of surface pasteurization and ehlortetraeycline on bacterial incidence on fryers the hydrolysis of grass hemicelluloses during ensilage post-harvest storage studies with selected fruits the science of food technology in venezuela beitrag zur aufbewahrung von sti~rkesirup in verzinkten ge-f~ben inactivation-rate studies on a radiation.resistant spoilage microorganism. ii. : thermal inactivation rates in beef the oceurrence and growth of staphylococci on packed bacon, with special reference to staphylococcus aureus zur verhiitung yon lebensmittelinfektionen in grobklichenanlagen dutch desinfektionsmabnahmen. ~rztl the influence of selected bacteria upon the flavor of a precooked frozen poultry product flour maturing and bleaching with aeyclie acetone peroxides effect of processing conditions on dry-heat expansion of bulgar wheat zur vcrwendung von pentachlornitrobenzol bei der lagerung yon kohl. dr. lebensmittel-rdsch. 59 [1963] nr. 1, s. 14115 los mati~res f6cales des pores et les selles des ouvriers d'aba~toir constituent une source permanente de diss6mination des salmonella studies on cooking fats and oils aspect sanitaire et l~gal aetuel des aliments conserv&s. rev. d'hyg over de betekenis van postduiven als besmettingsbron van levensmiddelen met salmonella-kiemen. ti]dschr. v. diergeneesk 87 over bet voorkomen van salmonella-kiemen bij slagerijen. tijdschr. v. diergeneesk 88 ursache und entstehung yon brotfehlern les salmonella des oeufs et ovoproduite frangais eg 6trangers the microstructure of baked products and doughs. food technol tomsto powder by foam-mat drying zitat: dt. lebensmittel-rdsch. 59 [1963] nr. 4, s. 123. --die verwendung yon gefrosteter saline zur butterherstellung. teil iv. die ergebnisse der in d~nemark, frankreich und in den l~iederlanden durchgefiihrten praktischen versuche und ihre bedeutung ffir die in der deutschen molkereiwirtschaft erfolgendo verwendung yon gefrosteter sahne bei der butterherstellung tenderne~ of the turkey meat as influenced by pre-cooling before proce~ing and hand masv~ging vortragsmaterialien flit die ern~hrungsproplldeutik. (erlruterungen zu insgesamt 6 groben sehautafeln.) 2. mitt. : behandlung der tafeln iv bis vi. ernahrungsforschung 7 die unterschiedliehe problematik und ihre konsequcnzen bei der bekrmplung der rinder-und schwefnefinnen salmonellae from flies in a mexican slaughterhouse factors affecting quality of pies prepared from frozen bulkpack red sour pitted cherries zur bedeutung antimikrobiellcr stoffc in der nahrung modified equipment for pasteurizing and deodorizing market milk and for pasteurizing, deodorizing, and slightly concentrating cheese milk adhesion of coatings on frozen fried chicken oob~age eheeae problems in production and sanitation. publle health aspects ~ber den einflub yon licht, 8auerstoff und tempera~ur auf die hal~barkoib yon verpaektem emmentaler ks in scheiben aktuelle notwendigkeiten -gesetzliche m6glichkeiten zur fischkfihlung in eis und seewasser techniques de recherche des salmonella dans les oeufs frais et de conserve food hygiene on board ship safety factors in water fluoridation based on toxicology of fluorides the effect of oiling before and after cleaning in maintaining the albumen condition of shell eggs lebensmi~t~l-aerosole. fette preservation of the natural color in processed sweetpotato products. i.: flakes. food technol temporary inhibition of fermentation in apple juice preservatives and artificial sweeteners the mechanism of the development of rancidity in frozen fresh pork sausage and practicable methods for its inhibition die entwicldung der trinkwasseriinoridierung in den usa microbiological principles in prcpaeking meats st~ndard-kapazit~tstest ffir die bestimmung der desinfektionswirkung yon desinfektionsmitteln in der milchwirtsehaft. internationaler standard fil/ii)f 18-1962 die anwendung einiger arteu, bzw. st~mme, yon propions~urebakterien zur herstellung bestimmter k~scsorten mit hohem vitamin b12-gehalt the extraction of pectins from apple marc preparations zur hygiene und ,di~tetik des rauchens studies on control of respiration of mcintosh apples by packaging methods. food teehnol effects of ingredients used in condermed and frozen dairy products on thermal resistance of potentially pathogenic staphylococci der frisehkllse und seine verpackung studies on the viscosity of mayonnaise. ii.: the influence of addition of vinegar on the vi~co~isy of mayonnaise e~'ec~ of chemical v~lditives on the spreading quality of butter. ii. laboratory and plant churnings studies on browning mechanisms of fruit juice products. i.: changes in chemical composition which accompany browning of commercial concentrated lemon juice during storage ergebnisse der dlg-qualit~tspriifung 1963 fiir speiseeis. dr. molkerei-ztg beeinttnssung versehiedenartig verpaekter lebensmittel dureh desinfektion mit formaldehyd grunds~itzliches zur stabilisierung und solubilisierung yon carotin und carotinoidpr~paraten riickst~nde yon pflanzensehutzmitteln, insektiziden und dergleichen in der nahrung und ihre bedeutung fiir die gesundheit absehliebende stellungnahme lebensmittel-rdsch langfristige nutritive anwendung yon antibiotilm in der tierern~hrung im hinbliek auf die menschliehe gesundheit mit besonderer beriieksiehtigung yon chiortetrazyklin nutritional studies on the utilization of distiller's stillage. part l: insolubles of me]lasses-butanol distiller's stillage auswertung der dlg-priifung fiir frischk~ise in verbraueherpaekungen zu den fermentativen eigensehaften der milchs~urebakterien (,laetobacillus meijerinek"), zugleieh ein beitrag zur vermeidung yon fehlfabrikaten bei roh-nnd briihwurst. arch. lebensmittel-hyg microbiological aspects of one-trip glass bottles as used by the carbonated beverage industry de bereiding van bouillon aktnelle milchhygienische aufgaben und zicle des organisation der ~berwachung der umweltradioaktivit~t unter besonderer beriieksichtigung der l~berwaehung des gehaltes yon lebensmitteln an radioaktiven stoffen. dr. lebensmittel bakteriologie der 8auermilcherzeugnisse l~ber die italtbarkeit yon lebensmittelkonserven preparation of aeid-modifid flour for tub sizing radiostrontium removal from milk. determination of apparent equilibrium constants of the exchange reactions of sodium, potassium, calcium, and magnesium wish amberlite ir-120 probleme der vitaminierung yon brot the effect of several operational variables on the rate of freeze-drying of beef studies on beef quality. x. effect of temperature, freezing, frozen s~orage, thawing, and p~ on the rate of hypoxanthine production. div. food preservation techn retardation of gelation in high temperature-short-time sterile milk concentrates with polyphosphates nonenzymatic bread browning and flavor. changes in amino acids and formation of earbonyl compounds during baking ttinweise fiir konservierende wirkungen synthetiseher senfslbildner naeh versuehen an fisehen neuo wege zur herstellung haltbarer fisch-pr~iserven behavior of ethylene dibromide, methyl bromide, and their mixtures. i. : in columns of grains and milled materials der einflui~ des wksserns auf die kartoffel irradiation of fruits and vegetables in india effect of storage in nitrogen on the soluble sugar and dry matter contents of ryegrass drying of seaweeds and other plants. v. throughcirculation drying of asophyllum nodosnm in a semi-continuous dryer niacin, thiamin, and riboflavin in fresh and cooked pale, soft, watery versus dark, firm, dry pork muscle nouvelles observations concernant la survie des salmonellae clans les fromages pyroearhonie acid diethyl ester as a potential food preservative the effect of phosphates on moisture absorption, retention, and cooking losses of broiler carcasses gur hygienisehen beur~ilung der trinkwasserverh~ltnisse des oberon vogtlandes -eine hydrobiologische s~udie. z. ges. hyg. 9 studies on preserving quality in market eggs rapid detection of faecal coliform bacteria in the food processing plant. j. milk food technol the relationship between the loss of water and carbon dioxide from eggs and the effect upon albumen quality plastic pacckaging of eggs. 2 study on improvement of digestibility of milk protein. i.: the effect of heating, adjustment of activity of calcium ion, addition of whey protein, homogenization, and elimination of coarse casein micelle from milk by ultracentrifuge on the digestibility of milk especially on the coagulability of it part iii.; the digebtibility of slightly hydrolized milk with proteinase and the preparation of rnill~ which has same eoagulability as human milk. g. agrie, chem. see study on improvement of digestibility of milk protein. part iv. : the nature of coagulation of casein of milk preparation which has same coagulability as human milk the influence of added microorganism on the quality of margarine. i. : the influence of mold inoculation die 8ilberung yon tafelw/~ssern. dr. lebermmittel-rdsch technological aspects of the radiation pasteurization of foods rapid hydration of dried fruits. food technol untersuchungen fiber polygalakturonase-enzyme aus sehimmelpilzen. 6. mitt.: eigenschaften der polygalakturonasen aus schimmclpilzen role of individual phospholipids as antioxidants association of veterinary food hygienists symposium on the marketing, transport, and slaughter of calves. iil: scientific aspects. ve~cr ricerche sulla resistenza della brucella abor~us helle salsicce. riv pr6senee des salmonelles dans les viandes. donn6es frangaises et 6tran-gbres biochemisehe vorg~nge inl fleisch bei der lagerung einflul3 des r6stgrades yon kaffee auf die extinktion w~briger extrakte und die menge der trockensubstanz die herstellung yon quark und weillk~e unter ansnfitzung ss eiweibstoffe der milch vcrluste yon vitamin b~ und c beim kochen und turmkoehen yon gemfise effect of chilled storage on the frozen storage life of whiting salmonellenfunde in einer importsendung amerikanischer tiefgefrierhiihner. arch. lebensmittel-hyg iron sulfide blackening in canned protein foods: oxidation and reduction mechanisms in relation to sulfur and iron raft research on food preservation by irradiation in poland no~: gas chromatography of chicken and turkey volatiles: the effect of temperature, oxygen, and type of tissue on composition of the volatile fraction l'inaetivation dens l'eau de meret l'eau d'alimentation de eertains entdrovirus de voedingswaarde van aardappelen van versehiuende re, sen en de invloed daarop van bemesting en bewaring effecb of l-arab]nose and d-xylose on dough fermentation and crust browning gelation of egg yolk corn carotenoids: effects of temperature and moisture on losses during storage salmonellenfunde in einer importsendung amerikanischer tiefgefriorhiihner. arch. lebensmittel-ttyg bacteriological examination of unbottled soft drink ~berbliek fiber kunststoff-folien und -kombinatlonen ale verpackungsmaterial in der mflchwirtschaft pigmentierung des eidottem bei gettiigel. wiss. versff. dr. ges. eruiilu'ung 9 s~ beltrag zur bedeutung wasserlsslieher hochmolekularer kohlenhydrate f'tir die verkleisterung der st~irke einfiul3 ehemischer verbindungen auf die antimikrobielle konservierungs-~toffwirkung. 1. mitt.: einflub verschiedener stoffgruppen auf die konservierungswirkung gegen aspergillus niger a quantitative s~udy of changes in dried skim-milk and lactose cnscin in the 'dry' state during storage the role of the major sugars of potatoes in ~he browning roa0tion during chipping probleme der zuverl~sigkeit yon kunststoffen zur lebensmittelverpackung in europi~ischer sicht bakteriologiseh-hygienisehe beur~ilung yon speiseeis weizenkeime ale wertvoller rohstoff-einige ~ragestellungen und probleme probleme der frischhaltung und haltbarmachung yon brot end backwaren the effect of selected polymers upon the albumen quality of eggs after storage for short periods preparation and quality evaluation of processed fruits and fruit products with sucrose and synthetic sweeteners the microflora within the tissue of fruits and vegetables changes in carbohydrate and phosphorus content of potato tubers during storage in nitrogen preparation of "natural" cow-milk fat globules; preliminary investigation of materials adsorbed at their surfaces lethal doses of gamma radiation of some fruit spoilage microorganisms alteration of post-mortem changes in porcine muscle by preslaughter heat treatment and diet modification ober die msglichkeiten end grenzen eines effects of polyphosphates on water uptake, moisture retention, and cooking loss in broilers flavors imparted to dairy products by phenol deriva aromatisehe crackproduktc yon sterinen. (i). z. ern~hrungs-wiss dose requirements for the radiation sterilization of food berichb fiber eine arbeitstagung bei der internationalen atomenergie-beh6rde in wien vom 12 zur bok~mpfung d6r rinderfinne zum einfiu]~ handelsfiblicher, in lebensmittelbetrieben gebr~uch-]icher desinfektionsmittel auf lactobakterien; zugleich ein beitrag zur desinfektion in der marinadenindustrie einflu~ chemischer umsetzungen bei trockenen lebensmittelgemischen in hinsich~ auf die lagerfestigkeit. vi. mitt. : lebensmittelgemische mit troekenmagermileh als hauptkomponente. z. lebensmittel-untersuchung u die technologie yon sauren milcherzeugnissen, insbesondere der sauermilcharten und sauerrahmarten effects of several edible coatings on poultry meat quality how to control insects in stored foods. part 2 die antibiotika und die ans ihrer anwendung fiir die ~iilehwirtsehaft sich ergebenden probleme zur haltbarkeitsverli~ngerung empfindlicher l~ahrungs-und genuflmittel dureh abpaeken unter vakuum. fette, seifcn the diffusion of hydrogen through tinplate containers packed with grapefruit juice effect of ice cream stabilizem on the freezing characteristics of various aqueous systems ist die infektion mit trichinen aus amtlich untersuchtem schweinefieisch im liehte der mathematisehen analyse der bestimmungen der fleischbcschau yon schweinefleisch msglieh? hygiene in milk production, processing, and distribution effect of pre-eooling eggs and cartons upon quality after storage a biological after-effect in radiation-processed chicken muscle accounting for farm tank milk factors related to the flavor stability during storage of foam-dried whole milk. iii. effect of antioxidants untersuchungen zur hygienischen beurteihing yon ~ietallverunreinlgungen in lvben~mitteln the effect of bleed time prior to scald and refrigerated storage upon bacterial counts in the axillary diverticula of the interclavicular air sac of chickens techniques de recherche des salmonella darts les viandes the serotypes of salmonella isolated from foods carotinverluste beider zubereitung der nahrung. wiss. vcrsff. dr. gcs. er-n~hrung 9 stability of ascorbie acid in a liquid multivitamin emulsion containing sodium fluoride the effect of storage time and holding temperature on egg interior quality in uganda uber den einflul3 versehiedener fangverfahren auf die qualit~t und lagerreserve der fische zerst~ubungstrocknung yon tomatenkonzentraten. dr. lebensmittel radiation pasteurization of fresh fruits and vegetables a bacteriological survey of certain processed meat~. part l population studies at packet and retail levels association of veterinary food hygienists symposium on the marketing, transport, and slaughter of calves. l : marketing and slaughter die kombinierte verarbeitung yon kartoffeln auf st~rke und alkohol (fortschrittsbericht) usaec program in radiation research preservation of certain fish and fruits biochemical and quality changes in chicken meat during storage at above-freezing temperatures inleidend onderzoek naar strnctuurveranderingen die ontstaan bi] verhitten van plantaardige produkten veranderingen van hot vetgehalte bij de bereiding van vlces a study on the relationship between the factors influencing the time of cheese salting maple sirup. xxi. : the effec~ of temperature and formaldehyde on the growth of pseudomonas geniculata in maple sap vacuum-tempering corn for dry. milling organoleptische eigenschappen, thiamine-en ascorbinezuurgehalte van enige week-en diepvriesgroenten growth of psyehrophiles. il : growth of poultry meat spoilage bacteria and some effects of chlortctracycline tests of corn stored four years in a commercial bin association of veterinary food hygienists symposium on the marketing, transport and slaughter of calves. ii. : the slaughter and inspection of calves. veter the effect of processing conditions upon the nutritional quality of vegetable oils berieht fiber den wisscnsehaftlichen kongrel3 1963 der dcutschen gesellschaft ftir ern~hrung (5 vortragsrcferate) an objective measurement of the freshness of ready-to-cook broilers the fieldman's responsibilities in milk quality and procurement studies on the bacteria found in the wine during its making. i.: multiplication of bacteria in wine and male-lactic fermentation hydrophilic colloids as additives in white layer cakes the acceptability of cooked poultry protected by an edible acetylated monoglyeeride coating during fresh and frozen storage istes zu vertreten, dal3 das fleiseh sehwachfinniger rinder auch in gebriitetem zust~nd eingcfrorcn wird? arch. lebensmittel-hyg =[efenlnfit.ierte kondensmilch als ursache yon fehlfabrikation bei schokolade. arch. lebensmittel.hyg. 14 [1963] nr. 1, s. 6110. m, ober die bedeutung aerober sporenbildner als bombageerreger yon wfimtehenkonscreen. arch. lebensmittel-hyg aluminiumfolio zur verpaekung tiefgekiihlter und gefriergetrockneter lebcnsmittel. fette fiber die milcldtuorierung. bull. schwciz. akad. reed. wiss vitamin stability in diets sterilized for germfree animal~ die trinkwasserversorgung ernliln-ungsstatistlk nutritional statistics african nutrition problems der vcrbrauch yon alkoholisehen getr~,nken in 0sterreich childhood nutrition in lapland overweight children in stockholm iron deficiency in the finnish population vitamin b12 deficiency in indian infants the indices of nutritional change in great britain dietary values from a 24 h recall compared to a 7-day survey on elderly people her vaststellen van de voedingstoestand van sen bevolldng in de tropen en subtropen dental effects of fluoridation of water with particular reference to a study in the united kingdom de voedlng van woonwagenbewoncrs nutritional attitudes of some london housewives de vocdingsgewoonten van bcjaarden in amsterdam community studies of drinking behavior fats and carbohydrates as factors on atherosclerosis and diabetes in yemenite jews nutritional beliefs among a low-income urban population algemene gezondimidsaspccten van de vocding in de ontwikkelingsgcbieden a comparative study of the nutritional adequacy of the morning intake of women clerical workers and women factory workers serum cholesterol in a military population. its relation to obesity and the military diet nutrient intakes of healthy older women analysis of the structures of food consumption by groups in japan thiamin (vitamin b,)-untercru~hrung in deutschland? lvied vortragsmaterialien ftir die ern~hrungsprops (erli~uterungen zu insgesamt 6 groben sehautafeln.) 2. mitt.: behandlung der tafein iv bis vi. erns 7 [1962163] nr. 4, s. 6131634 zur ern~ihrungssituation in arbeitexfamilien aus verschiedcnen bezirken der ddr. 2. mitt. : ern~hrungssoziologischc answertung der lebensmittelverzehrungen in 6 itaushaltungen mit 2 erwachscnen und 2 kindern~ stand 1950 studies in infantile malnutrition. i. : nature of the problem in peru zur ~ethodik yon ern~ihrungserhebungen bei der gemeinschaftsverpflegung weight changes in relation to birthweight of papuan, indonesian, and chinese children during the first two weeks of life numbers of tasters required to determine consumer preferences for fruit drinks onderzoek naar de menupatronen in de noordoostpolder smoking habits of medical and non-medical university staff i**cs and potassium in people and diet. -a study of finnish lapps. ann. acad. scientiarum fennicae a ~berbliek fiber die radioaktivit~t der in 0sterreich im jahre 1961 konsumierten lebensmittel diet and plasma cholesterol in 99 bank men der mengenmi~bige getr~inkeverbrauch je einwohner im bundesgebiet predictors of human food consumption use of goverument.donated foods in a rural community bericht fiber die durum-und teigwarentagung der arbcitsgemeinschaft der oetreldeforschung e. v. vorn 12. bis 13. miirz voeding van leerlingen van con lagere teehni~eho school. ii. calorie~in-en nutriiintenwaarde nutritional deficiencies in developing countries dietary survey in surinam vitamine a-tekor~en op de aarde schwierigkeiten beim erreichen einer vollwertigcn ern~ihrung in ausgew~hl-ten vcrbrauchergruppen die entwicklung des brot-und getreideverzehrs in der neueren zeit. wiss. ver6ff. dr. ges. ern~hrung 10 n~rwert und zusammensetzung yon lebens. und futtermltteln nutritive values, composition of food~tuffe and f 9 physical chemistry of ice cream vitamin e in human nutrition appraisal of nutritional adequacy of infant formulas used as cow milk substitutes enkele gegevens betreffende de calorisehe waarde van klsine hepjes, gerechtcn en maaltijden the public health aspects of the use of antibiotics in food and foodstuffs. report of an expert committee niihrwertminderung dutch zubereitung der nahrung metals and other elements in foods die farbe der nahrungsmittel in anthropologischer sicht the enzymatic destruction of carotene and carotenoids foodstuff flavors. some factors affecting the flavor of sodium caseinate chemical and radiochemical composition of the rongelapese diet the organic constituents of food. i. : lettuce the influence of dehydration of foods on the digestibility and the biological value of the protein a stfidy of two methods of assessing vitamin b6 nutriture mincraisalze mad spurenelemente in der nahrung distribution of the bound form of nicotinic ac|d in natural material~ the distribution of c~rotenoids in nature and their biological significance zur bedeutung antimikrobieller stoffe in der mahrung die konsistenz yon margarine mad fetten an improved nutrient solution for diploid chinese hamster and human cell lines extraneous materials in foods and drugs the composition of food flavors studies on pantothenic acid intake. i. pantothenic acid content in japanese foods haben wir mangel an essentiellen fettsiiurcn? phonolcarbons~uren in menschlichen nahrungsprodukten. zum vorkommen yon phenolcarbons~uren in menschlichen nahrungsprodukten und ihr einttud auf den intermedi~ren sboffwechscl drugs in feeds relationship between the sulphur/nitrogen ratio and the protein value of diets gums in foods zur definition der begriffe ,aroma" und begriff und aufgabe dii~tetischer lebensmittel valettr vitaminique des carot6nes pour rhomme. wiss. versff. dr. ges. ern~hrung 9 internationales rundgespriich fiber lebensmittelchemische probleme in wiesbaden und eltville a. rh. (4 vortragsreferate) consumer awareness of texture and other food attributes organisehe und organisierte substanz in der lebensmittelchemie frost resistivity of fruit plants californ'ia association of chemistry teachers : inorganic nutrients in the sea fluoride in food antibiotics in feeds and other products planktorm as foods relation between color of cranberries and color and stability of sauce berieht fiber die vortragstagung des fachverbandes lebensmittelchemie der chemischen gesellsehaf$ in der ddr vom 19. bis 21 bulletin on tobacco evaluation of algae as a food for human diet~ digestibility of high-amylose corn starch. nutrition red. 21 [1963] nr. 1, s. 27/28. 1~. n. : comparative evaluation of corn mesa and steam-processed whole corn flours the major anthocyanin pigments of vitis vinifera varieties flame tokay, emperor, and red ~alaga peonidin-3-monoglucoside in vinifera grapes formation and distribution of amylosc and amylopectin in the starch granule nutrient in seeds. amino composition of some seeds sugar levels in fruits of the lowbush blueberry estimated at four physiological ages the relation of pectic substances to firmness of processed sweet potatoes (ipomoea berates) processed vegetable produc~s the protein composition of different flours and its relationship to nitrogen content and baking performance relationship between 'antitryptic factors' of some plant protein feeds and products of proteolysis precipitable by trichloroacetic acid. g. sci. food agric a thermostable haemolytic factor in soybeans foam-mat dried orange juice. i. time-temperature drying studies bound" growth inhibitor in raw soybean meal leaf analysis as a guide to the nutrition of fruit crops. ii. : distribution of total n, p, k, ca and mg in the laminae and petioles of raspberry (rubns idaeus l.) as influenced by soil treatments nutritive value of pumpkin seed. essential amino acid content and protein value of pumpkin seed (cueur bi~a farinoaa) effect of cooking and of amino acid supplementation on the nutritive value of black beans (phaseolns vulgaris l.) supplementation of cereal proteins with amino acids. iv.: lysine supplementation of wheat flour fed to young children at different levels of protein intake in the presence and absence of other amino acids uber den chemischen total ascorbic acid in potatoes. raw, fresh, mashed, and reeonstituted flakes moisture contents of hard red winter wheat as determined by meters and by oven drying, and influence of small differences in moisture content upon subsequent deterioration of the grain in storage rheological studies with canned tomato juice the chemical composition of maple sugar sand soluble carbohydrate content of varieties of te~raploid ryegrass natiirlicher gehalt und stabilit~t yon carotine11 und carotinoiden in citrnss~ften ~ber wein und weinuntersuchungen fatty acids and other lipids in mayonnaise cyclic fatty acid yields from linseed oil factors ~ffecting enzymatic solubilization of beef proteins weibulls original ring, en ny medeltidig varvetesort. (a new medium early variety of spring wheat, weibull's ring.) agri hortique genetiea 21 ober die askorbins~uresynthese in zerschnittene11 kartoffeln die bestimmung der amylaseaktivit~t und einige studicn fiber amylaseaktivit~t in gekeimtem roggen effect of processing conditions on dry-heat expansion of ~ulgar wheat oils, fats, and waxes ~.~ber das 01 der johannisbro~.kerne. fetto, seifen fruit and fruit products uber die variabili~it einiger eigcnschaften der kartoffelstilrke in abhiingigkcit yon witterung a short.term effect of weather on malie acid in pineapple fruit the specific surface of flour and starch granules in a hard winter wheat flour and in its five subsieve-size fractions oranges and lemons factors affecting quality of pies prepared from frozen bulk-pack red sour pitted cherries studies on the consish~ncy of thiamin and protein contents of pure.bred strains of rice a comparison of the nutritional value of protein from several soybean frac4ions zum vitamin-und aminos~uregehal~ yon maisquellwasser dark discoloration of canned all-green asparagus. i. chemistry and related factors enzymatic enhancement of flavor peetinestcrase in normal and abnormal tomato fruit storage effects on winter squashes. varietal differences and storage changes in the ascorbie acid content of six varieties of winter squashes grape pigments. concord grape pigments corn meal as a source of ribonuclease banana odor components. volatile components of bananas. part i. isolation of an odor concentrate. part il separation and identification lipids of algae. ill. : the components of unsaponifable matter of the algae chlore]la volatile esters of bartlett pear. ii studies on the nutritive value of raw and cooked soybeans for growing rats and swine and their effect on fat firmness characterization of fruit juices by acid profiles nitrate content of beets, collards, turnip greens lysine fortifications of wheat bread fed to haitian school children studies on the flavor of green tea. par~ iv. : dimethyl sulfide and its preeursor funktionelle eigenschaften yon lehens-mittclst~rken ~)ber das vorkommen yon xylit im speisepi]z champignon ein beitrag zur znsammensetzung yon apfeisinens~ften aus spanischcn und l~iarokko-apfelsinen an examination of the free amino acids of the common onion (allium cepa) a trypsin inhibitor in wheat flour the protein quality, digestibility, and composition of algae, chlorella 71105 chemical and color changes in canned apple sauce digestibility of the a-cellulose and pentosan components of the cellulosic mieelle of rescue and alfalfa safeness and serva. bility of meringued pie alcoholic beverages diurnal-nocturnal changes in the starch of tobacco leaves sugar and sugar products modification of flour proteins by dough mixing: effects of suffhydryl-blocking and oxidizing agents ~ber das haferprotein. z. lebensmittel-untersuchung u sodium and potassium in wines and distilled spirits non-volatile organic acids of the dwarf cavendish (chinese) variety of banana~ biological evaluation of soybean meal and cottonseed meal by amino acid digestibility and protein efficiency ratio studies. oiss. abstr. 23 [1963] l~r oxidation-reduction potentials of sak~f and synthetic sak6. xi.: on the relationship of the various fermenting processes of sak~ to oxidereduction potentials and indicator time test (i.t.t.) values of sak6 mash neue wege zur ern~hrungsphysiologischen aufwcrtung von getreideerzeugnissen cereal products ascorbie acid in dehydrated po~es die eiweibqualit~t yon ,getoastetem" (dampferhitztem) und ungetoastetem sojaextraktionssehrot color studies on processed dried fruits studies on the basic amino acid of the soy sauces and the seasoning liquids. ii.: the quantitative changes of l-arginine in the process of soy sauces brewing studies on the flavorons substances in soy sauce. xxii. : the differences between the soy sauce made from soy bean and wheat and that made from defatted soy bean and wheat feeding value of soy milks for premature infants flavors and non-alcoholic beverages fat content and fatty acids in some commercial mixes for baked products sensory examination of four organic acids added f~ wine 13ber die inhaltsstoffe der robktmtanie und versuehe zu ihrcr gehaltsbestimmung. diss. univ. hamburg, 3.2 malt beverages, sirups, extracts, and brewing materials vitamin b 6 and niacin in potatoes. retention after storage and cooking chemical investigation of some wild indian legumes zusatzstoffe der margarine. forte componen~ glyeerides of an indian fresh-water fish fat einflub des rsstgrades yon kaffce auf die extinktion w~$riger extrakte und die 1v[enge der trockensubstanz gaschromatographische untersuehungen yon fusclslen aus vcrsehiedchen g~irprodukten. 1. mitt.: problemsteilung und literaturfibemieht de voedingswaarde van aardappelen van versehillende rassen en de invloed daarop van bcmesting en bewaring eleetrophoretic separation of beet pigments studies on the growth-promoting value and digestibility of passion fruit seed oil polycyclisehe und aliphatisehe kohlenwasserstoffe dc~ tabakrauehes carotenoid, oil, and tocopherol content of corn inbreds location and possible role of esterified phosphorus in starch fractions untersuchungen fiber die chemischen u beim a]tern yon r6stkaffee. 1. mitt.: gaschromatographische analyse der leichtflfichtigen aromabestandteile nature, origin, and prevention of hydrogen sulphide aroma in wines the magnesium contents of soil and crops versuehe zur ehemischen differenzierung der eiweibst~ffe des weizens und roggens lemon juice composition. iii.: characterization of california-arizona lemon juice by use of a multiple regression analysis weizenkeime als wertvoller rohstoff -einige fragestellungen und probleme isolation of gram quantities of a rhamnoglucoside of apigenin from grapefruit determination of distribution of water in wheat grains by interference microscopy preparation and quality evaluation of processed fruits and fruit products with sucrose and synthetic sweeteners changes in carbohydrate and phosphorus content of potato tubers during storage in nitrogen chemical composition of some natural and processed orange juices effects of various factors in the candy test zum stand der kenntnlsse fiber die v{eclmelwir-kung zwischen nativer sts und wasser some volatile compounds from cooked potatoes firmness of canned apple slices as affected by maturity and steam-blanch temperature nutritive values of ten samples of western canadian grains proteins of wheat and flour. the separation and purification of the pyrophosphate-soluble proteins of wheat flour by chromatography on dear-cellulose changes in quality and composition produced in wine by s~ gamma irradiation citrus essential oils. iii. evaluation of silician natural lemon oils mineral analysis of plant tissues a. : nature of colloids in clarified cane juices studies on amino acid content of rice. i. : amino acid composition of polished rice glutelln estimated by beckman amino acid analyzer yliichtige carbonylverbindungen in honig neue aminos~iuren in h6heren pflanzen studium der wirkung der gammastrahlung auf die l-ascorbins~iure flour liplds and oxidation of sulfhydryl groups in dough zur kenntnls eincr weiteren in der sti~rke vorkommenden kohlenhydrat-komponente. ern~ihrungsforschung 8 lemon juice composition. ii. : characterization of california.arizona lemon juice by its polyphenolic content lemon juice composition. i.: characterization of california-arizona lemon juice by its total amino acid and 1-malic acid content safflower amino acids amino acid composition of safflower kernels, kernel protein, and hulls, and solubility of kernel nitrogen citrus fruit enzymes. i. : ascorbie acid oxidase in oranges untersuehungen fiber die verf~rbung gekochter kartoffeln an den sorten des kulturlrartoffelsortiments ides instituts ffir pflanzenziiehtung groi~-liisewitz nutritive value of red kidney beans (phaseolns vulgaris) for chicks instability in potable spirits. ii.: rum and brandy effect of size classification and maturity on the protein content of alaska and perfection peas ma~tr~, d. c.: ascorbie acid retention and color of strawberries as related to low-level irradiation and storage time historical aoac data on four fema samples of vanilla extract the acid-extracted pentosan content of wheat as a measure of milling quality of pacific northwest wheats petroleum ether extraetables in tobacco isolation, origin, and synthesis of a bread flavor constituent the protein composition of airclassifled flour fractions * studies on the flavor of green tea. v. : examination of the essential oil of the tea-leaves by gas lipid chromatography nutritive value of starches. iv.; comparison of digestibility of 15 natural starches estimated by a new procedure 1o c lebensmittel tierischen ursprungs _foodstu~$ o/animal origin n.n.: gdch-faehgruppe ,lebensmib~el. und gerichtliche chemie bericht fiber die vortragstagung des fachverbandes lebensmittelchemie der chemischen gesellsehaft in der ddr yore 19. bis 21 a taxometric study of the propionic acid bacteria of dairy origin comparisons of the caseins of buffalo's and cow's milk matiirlicher gehalt und stabilit~t der carotinoide in fetten und milchprodukten. wiss. versff. dr. ges. ernhhrung 9 antibiotics in milk vitamin a and d enrichment of nonfat dry milk some characteristics of yolk solids affecting their performance in cake doughnuts. i. effects of yolk type, level, and contamination with white proteine des eidotters post-mortem changes in the muscles oflandrace pigs t~ber den fettgehalt yon flcischkonserven. dr. lebensmittel der einflul~ der verfahrenstechnik auf die ks163 jahreszeitliche einfliisse alff den gehalt der fischmuskulatur an freien ami-nos~iuren u. deren bedeutung fiir die qualitiit fangtechnik und fisch-qualit~t. fette spcei~c distribution of fatty acids in marine lipids a comparison of pigs slaughtered at three diffcrcn~ weights. i. : carcass quality and performance a comparison of pigs slaughtered at three different~ weights. ii. : association between dissection results, various measuremen~ and visual assessments a note on the effect of heat on the colour of goat's milk chemical and nutritional changes in stored herring meal. 4.: nutritional significance of oxidation of the oil relation of pork muscle quality factors to zinc con~ent and other properties the chemical nature of the characteristic flavor of cultured buttermilk occurence of vaniuin in hea~ed milks the electrophoretie properties of the proteins in cottage cheese curd the influence of post-mortem glycolysis on poultry tenderness seasonal variations in cod liver oil isolation and characterization of the flavor components of rancid pork some problems in the evaluation of egg albumen quality quality evaluation studies of fish and shellfish from certain northern european waters indices for lamb carcass composition subjective and objective evaluations of prefabricated cuts of beef 0ils, fats, and waxes die bildung yon eiskristallen in diinnen milchschichten. milchwissensehaft 18 the incidence of bacteria in cheese milk and cheddar cheese and their association with flavour body composition of market weight pigs some factors affecting tenderness of turkey meat ovine bioenergetics and nutritional efficiency, with special reference go forage utilization die ziichtung yon fleisehsehweinen und die folgeerseheinungen, die sich insbesondere im hinbliek auf die qualit~t yon fleisch und fett ergeben. arch. lebensmitgel-ityg 0n the structure of highly unsaturated fatty acids of fish oils by high resolution nuclear magnetic resonance spectral analysis the fatty acid composition of the milk fat of cows grazing on ryegrass at two stages of maturity and the composition of the ryegrass hpids effect of intrauterine infusion of penicillin-streptomycin and furacin and vaginal deposition of furacin on chemical residues tevei~ in millr beziehungen zwisehen l-aseorbinsaure und milch comparison of chemical and organoleptic data obtained on thawed and unthawed frozen cod, haddock, and perch fillets die ~4m~uosfiurenzusammensetzung der ziegenmflch und des ziegenmileh-caseins food flavors and odors. meat flavor: lamb dairy products de ehemische samenstelling van visen visprodukten chemical studies on the herring (clupen harengus). vii.: collagen and cohesiveness in heat-processed herring and observations on a seasonal variation in collagen content growth and pro~eolycie activity of pseudomonas fluoresccns in eggs and egg products the fatty acid composition of some perirenal and subcutaneous beef depot fats inactivation of peroxidase in milk by homogenization a study of the "cured meat" color producing reaction and the effects of some curing adjuncts t~yoer den fettgchalt yon br'tihwiirsten stress effects, eareass composition, and carcass quality in lambs effect of chemical additives on the spreading quality of butter. ii. laboratory and plant ehurnings preliminary studies on protein and moisture relationship in fresh and proeessed hams die zusammensetzung des kuhmilchfettes in abh~ngig-keit yon der ffitterung. fette chemical characterization of off-flavors in concentrated and nonfat dry milk zur ausseheidung yon xanthindehydrase mid molybdiin in der kuhmilch copper distribution in milk during early lactation die physikaliseh-ehemischen ursaehen der hitzestabilitet yon mileheiweil]stoffen. milehwissenscha sobn~a: ~oer einige verenderungen in den caseinfraktionen normaler und anomaler milch (colostralmilch und milch an lviastitis erkrankter kiihe). milchwissensehaft 18 some characteristics of yolk solids affecting their performance in cake doughnuts. ii. variability in commercial yolk solids zum problem des znsammenhanges zwisehen der konsistenz und der physikalischen struktur der butter. fette relationships between milk fat acidity, short-chain fatty acids, and rancid flavors in milk induced and natural inhibitory behavior of milk and significance to antibiotics disc assay testing. j. dairy sei. 46 [1963] nr. 2, s. 95ff. (7 s.). --some distribution patterns of cottage cheese particles and conditions contributing to curd shattering natural inhibitory eharacteristies of some irish manufacturing milks thermophylie aetinomycetes in milk and dairy products. mikrobiologiya the free fatty acids of purdue swiss-type eheese die zusammensetzung yon siilzen lind ihre beurteilung im 1regierungsbezirk diisseldorf not~ on tyrosine production in frozen stored liver studies on the muscles of meat animals. hi. : comparative composition of various muscles in pigs of the three weight groups studies on beef quality. x. effect of temperature, freezing, frozen storage, thawing, and pe on the rate of hypoxanthine production. die. food preservation t~chn increased iodine in milk as a countermeasure for ~liodine time-temperature studies of baked, loaves. meat, fish, and poultry vergleichende untersuehungon an butter und einem butter~hnli-chen umgeesterten fort. forte, seifen, anstrichmittel 65 zur beziehung zwisehen fettgehalt und wassergehalt bei ungewa~ohener s/il~rahmbutter (fritzbutter) variation of ovine fat composition within the carcass studies on the properties of new zealand butterfat. vii. effect of the stage of maturity of ryegrass fed to cows on the characteristics of butterfat and its carotene and vitamin a contents studies on turkey body composition. 2. poultry sci thermal conductivity of beef studies on turkey body composition. 1 free fatty acid, tyrosine, and 1~ changes during ripening of blue cheese made from variously treated milks l : factors influencing the nutritional value of fish flour. il: availability of lysine and sulphur amino acids. canad characterization of flavor compounds isolated from evaporated milk effect of egg yolk size on yolk cholesterol concentration ~tudo immuno~lectrophor~tiquo du lair dans los divers types de mammites. i. milchwissenschaft 17 rdsultats hemmstoffe in der anlieferungsmflch und methoden zu ihrem nachweia eiweibverenderungen gefriergetroekneter muskulatur meat and meat products effect of high doses of vitamin a palmitate on vitamin a aldehyde, esters, and alcohol and carotenoid contents of hen's eggs. brig. j. nutrition 17 [1963] nr. 2, s. 235/242. --the amounts of vitamin a aldehyde, esters, and alcohol and of earotenoids in hen's eggs and in day-old chicks nutritive value of marine oils i. : ]~lenhaden oil at varying oxidation levels, with and without antioxidants in rat diets a quantitative study of changes in dried skim-milk and lactose-casein in the 'dry' state during storage physico chemical characteristics of canadian milk fat. unsaturated fatty acids collagen content and its relation t~ tenderness of connective tissue in two beef muscles ~ber eine braune verf~rbung yon mariniertem hering. dr. lebensmitbel versuche fiber den sonnenlichtgesehmaek in mit ass markierter milch effect of unequal milking intervals on lactation milk, milk fat, and total solids production of cows wei~re untersuehungen fiber die nitratreduktase verschiedener an der reifung yon rohwurst beteiligter mlkroorganismen nutritive value of leg of lamb roasts. l~oisture, energy, protein, fat, and iodine values ~ber einige gul~sigkai~s~renzen bei konsistenzfehiern yon butter influence of linoleic acid content of milk lipids on oxidation of milk and milk fat fish hydrolysates-iii.: influence of degree of hydrolysis on nutritive value einige beobaehtungen fiber die bildung des durch lieht verursaehten oxydationsgesehmackes s.). zitat: dt. lebensmittel comminuted meat emulsions: factors affecting meat proteins as emulsion stabilizers factors related to the flavor stability during storage of foam-dried whole milk. iil effect of antioxidants upgrading the indigenous poultry of uganda. hi. : shell and egg interior quality relation between carcass composition and live weight of sheep diethylstilbestrol occurence in eggs of subcutaneously injected hens biochemical and quality changes in chicken meat during storage a~ above-freezing temperatures investigations on the allerged goitrogenie properties of milk fish and other marine products bioehemieal properties of pork muscle in relation to curing potassium content of dried milk vergleiehende histometrische untersuehungen fiber den kollagengehalt yon brfihwfirsten a comparison of the volatile compounds of fresh and decomposed cream by gas chromatography studies on the volatile carbonyl compounds in ladino clover and their influence on the flavor of milk aut~xidation of fish oils. ii.: changes in the carbonyl distribution of autoxidizing salmon oils the public health aspects of the use of antibiotics in food and feedstuffs. repor~ of an expert committee composition and digestibility of corn silage as affected by fertilizer rate and plant population factors influencing the nitrate content of forage the component sugars and rate of hydrolysis of forage hemicelhflose as related to digestibility digestibility trials on forages in trinidad and their use in the prediction of nutritive value acetyl-(para-nitrophenyl)-sulfanilamide in feeds distribution of major and trace elements in some common pasture species 0-dimcthyl 0-(2,4,5-trichlorophcnyl)phosphorothioate) in feeds feeding value of low-moisture alfalfa silage from conventional silos ovine bioenergeties and nutritional efficiency, with special reference to forage utilization a system for naming and describing feeds, energy terminology, and the use of such information in calculating diets supplemental methionine in a sixteen percent protein diet for laying chickens l : organic arsenicals in feeds cellulose degradation by enzymes added to ensiled forages influence of corn distillers dried grains with sohbles on the feeding value of wheat silage zinc content of certain feeds, associated materials, and water der natiirliche gehalt und die stabilit~it yon carotin und carotinoiden in lieu und silage forage digestibility. benzene-ethanol extracts of forage and faeces as indicators of digestibility the prediction of the metabolizable energy content of poultry fcedingstuffs from a knowledge of their chemical composition factors affecting the metabolizable energy content of poultry feeds. 11 facters affeeting the metsbohzablo energy content of poultry feeds unidentified chick growth factor in fish solubles diet and histamine in the ruminant. occurrence of histamine in silage ethopabate in feeds die isolierung yon apocarotinalen aus luzernemehl isoflavone contents of red and subterranean clovers metabolizable energy of some oil seed meals and some unusual feedstuffs ii methoden der untersuchung yon lebens-und futtermitteln techniques analysis of foodstuffs and feeds n.n.: gdch-faehgruppe analysis of foods by neutronaetivation techniques continuous measurement of dissolved solids in food processes by critical-angle refractometry berieht fiber die vortragstagung des fachverbandes lebensmittelchemie der chemischen gesellschaft in der ddr vom 19. bis 21 a rapid test for anionic detergents in drinking water fortschritte in der lebensmittelehemio dureh moderne analysenmethoden direct potcntiometrio determination of chloride in cheese modification of the polarimetrie starch determination on hig-hamyloso corn ~iethoden der ]~berwachung des wassers auf radioaktiviuit. btmdes prediction of quality in protein concentrates by laboratory procedures involving determination of soluble nitrogen direct chromatographic analysis of milk die eignung der bakteriologischen untersuehung yon kannenmilchproben als grundlage eines eu~ergesundheitsdienstes. arch. lebensmittel-i~yg nachweis fremder carotinoide in 0rangensiiften mittels diinnschichtchromatographie. i)t. lebensmit~el-l~dseh determination of phosphate composition of stock food calcium phosphate. 5. assoe. off. agric. chemists 46 molybdenum in plants and animals. determination of molybdenum in biological materims with dithiol control of copper interference the determination of dissolved oxygen in canned drinks using a vibrating mercury-plated platinum electrode determination of chromium and lead in periodic acid solution and dialdehyde starch the utilization of infrared and ultraviolet spectrometric procedures for assay of pesticide residues ultramicro determination of potassium and sodium in biologic fluids gum quautativen naehweis des pektins und der alginsiiure ein schliffapparat zur abtrennung yon flfichtigcn stoffen mittel~ wasscrdampfdcstillation ~tude par chromatographic on phase gazeuse des acidea gras du beurre fabriqu6 en italic et clans d'autres pays. application ~, la recherche des falsifications clans le bcurre commercim. ann. falsiticatiorm expertise chim note on the determination of caffeine in coffee a comparison of the press method with taste-panel and shear measurements of tenderness in beef and lamb muscles zur diehtebestimmung der milch mit der neuen milehspindel. lebensmittelchem, u. geriehtl. chem. 17 [1963] nr. 6, s. 113/116. --aufschlu6-.i~thercxtrakt und titrationswert bei der teigwarenunbersuehung als beispiel einer dynamisehen lebensmittelanalyse quantitative measures of carcass composition and qualitative evaluations fruit preservatives analysis. determination of calcium in cherry brines by versenat~ titration: elimination of anthocyanin interference by means of carbonyl reagents, g. agric. food chem allgemeine prinzipien der analytik yon carotinen und carotinoiden zur bestimmung yon ethoxyquin kolorimctrische bestimmung yon dipterex-riickst~nden yon lebensmittein the direct determination of shear stress-shear rate behavior of foods on the presence of a yield stress methods for evaluating bhe feeding quality of meat-andbone meals a paper chromatographic method for determination of vanillin and ethyl vanillin in vanilla flavorings ~drber die anwendung der papierchromatographisehen analyse auf dem fettgebiet. 4. mitt.: uber 5ls~iurereiehe samenole. ermittlung der konsti~uierenden fettsiiuren der samensie yon margosa (azadiraehta indies), cashewkern (anacardicum oecidentale) und putranjiva roxburghli. nahrung 7 die jodzahl des riickenspeeks im verhiiltnis zu der qualit~t des futterfettes, dem alter der schweine und dem fettungsgrad bei sehweinen der ditnisehen landrasse determination of parathion, methyl parathion, epn, and their oxons in some fruit and vegetable crops an improved chromatographic method for determining trace elements in foodstuffs determination of guthion residues on fruits techniques used in meat flavor research the analysis of edible oils contaminated with synthetic ester lubricants colorimetrische bestimmtmg yon nitrat und nitrit in biologisehem material confrontation de quelques proe~d6s de dosage iodometrique de l'anhydride sulfureux dans les vins zur anwendung der massenspektroskopie zur strukturermittlung yon naturstoffen, mit besonderer berfieksiehtigung der lebensmittelanalytik z lebensmittel cellulose solubility as an estimate of cellulose digestibillty and nutritive value of grasses the 2-thiobarbiturie acid reagent for determination of oxidative rancidity in fish oils bet die eignung yon daphnia magna zur ermittlung yon riieksti~nden auf frisehem 0bst und gemfise bemcrkung zum diinnschiehtchromatographischen kakaoschalennaehweis nach the determination of vitamin a in animal tissues and its presence in the liver of the vitamin a-deficient rat elution column preparation of leaf sample for flame photometry. ii. : determination of calcium in tobacco enzymatic-ultraviolet method for determination of uric acid in flour die bestimmung der amyiaseaktivit~t und einige studien fiber amylaseaktivit~it in gekeimtem roggen identification and determination of ascorbic acid (vitamin c) with janus green and its localisation in mitochondria cho]estehnbestimmung im kleinen laboratorlum chick edema factor. iii.: application of mieroeoulometric gas chromatography to detection of chick edema factor in fats or fatty acids bioassay of chick edema factor. 1962 collaborative study determination of nih4te and nitrate in meat products the measurement of the surface areas of milk powders by a permeability procedure sedimentbeurteilung und sehaim-~iastitis-test als sortierverfahren zur ermittlung yon sekretionsstsrungen bei der 1~iassenuntersuchung yon milchproben aoac methods for nutritional adjuncts die ermittlung der ribonucleins~ure im pflanzenmaterial beitrag zur analytischen beurteilung des frischezustandes der pharmazeutisch verwendeten 01e und fe~te sehnellbestimmung yon kupfer in fe~n applications of oscillographic polarography to the determination of organophosphorus pesticides. ii. : a rapid screening procedure for the determination of parathion in some t~its and vegetables zur standardisierung der vitaminb~-bestimmung in getreide und getreideprodukten eine mikromethode zur bestimmung des fettgehaltes der milch kleiner laboratoriumstiere the determination of organophosphato pesticides and their residues by paper chromatography die l~fikrochemie beim studium yon nahrung und erni~hrung aearicide residues. an improved method for kelthane residue analysis with applications for determination of residues in milk collaborative study of the determination of ethoxyquin in feeds ~rber den naehweis yon quellstoffcn in fleischwaren und m6gliche stsrungen durch andere polysaccharide ersatz manueller labormethoden der l6sungsspektralanalyse durch den automaten determination of total acids in wines: american society of enologists determination of aldehydes in wines and spirit~ by the direct bisulilte method ~fber einen vereinfachten nachweis des vitamin b12 mit poteriochromonas slipitata extraction of nys~tin in animal feeds for microbiological analysis zur quantitativen bestimmung der sorbinsi~ure mit dem thiobarbitur-s~urereagenz cottage cheese problems in production and sanitation. quality control in cottage cheese sitzung des arbeitskreises berlin der gdch-fachgruppe lebensmittelchemie und gerichtliche chemie am 23. 11. 1962 in ]~erlin-dahlem (2 vortragsreferate) ein neues elektronisches sctmeuverfahren zur ermittlung der ~risehe yon seefischen fatty acids of lard. a. identification by gas.liquid chromatography oxydative abbauprodukte der l-aseorbins~ure. 1. mitt. : papierchromatographischer l~achweis analysis of orange juice for total earotenoids, carotenes, and added betacarotene. food technol. 17 [1963] nr. 3, s. 95/98. u. r~ck~, a. a. : refractometrio measurement of soluble solids in orange juice analysis of iron chelates in plant extracts. il: ferric ethylenediamine'bis'(~176 acid) determination of n-aeetylglucosamine-1-phosphate and n-aeetylglucosamine in milk arsenic in foods: collaborative comparison of the aminemolybdenum blue and the silver diethyldithiocarbamate methods improved method for testing macaroni products neuere beitri~ge zur chemic der st~rkefraktionen. 13. mitt.: die mikro-ameisens~urebestimmung bei der perjodat-0xydatonsbestimmungsmethode yon stiirke recherche des falsifications dans les extraits de vanille. ann. falsifications expertise chim bestimmung des gesamtstckstoffgehaltes yon milch nach der kjwld~t:l-methode. internationaler standard fil vorteile und grenzen des einsatzes yon markiertem phosphat bei untersuchungen am hiihnerei paper chromatography of carotene and carotenoids determinaton of sevin insecticide residues in fruits and vegetables insecticide residues in meat and eggs. determinaton of sevin insecticide and its metabolites in poultry tissues and eggs bcstimmung der jodzahl yon fetten und 01en mittels n-bromsuccinimid. 2. mitt.: l~ber eine !~i6gliehkeit zur bestimmung der gesamtjodzahl yon el~iostearins~ure und holz61. nahrung 7 [1963] nr. 5, s. 375/381. kxrr:~e~r, m. a. : ~3ber die anwendbarkeit des thiobarbi~urs~iuretestes boi der untersuchung yon milchprodukten application of gas chromatography to the measurement of gas permeability of packaging materials a sensitive method for quantitative microdetermination of lipids comparison of chemical and microbiological methods for the determination of procaine penicillin in prcmixes and mixed feeds electrophoretc analysis of flour proteins from various varieties of wheat katalytische methode zur bestmmung kleinster manganmengen in lebensmitteln am beispiel der milch eine methode zur papierchromatographischen qualits yon silagen comparison of methods of measuring potassium in pork and lamb and prediction of their composition from sodium and potassium electron capture gas chromatography for determination of ddt in butter and some vegetable oils eine methode zum schnelinachweis yon nitriten in yleiseh-und wurstwaren. arch. lebensmittel-hyg determination ofglyodin residues on pears and peaches eleetrophoretic analysis of flour proteins erstes internationales symposium fiber methoden zur analyse yon lebensmitteln in bordeaux-tatence (frankreich) veto 8. bis 12. oktober on the problem of luminescence technique of protein definition in milk beitr~ge zur aminos/iuren-bestimmung in biologischem material aktuelle fragen der lebensmitteluntersuehung, insbesondere der histologischen wurstanalyse untersuchungen yon importiertem tiefgefrorenem tiasenfleisch argentinischer herkunft fish hydrolysates. iv.: microbiological evaluation untersuehungon zum naehweis yon emulgatoren in lebensmit~eln. 3. mitteilung. forte use of a slice-tenderness evaluation device with pork studies on improvements in quantitative paper chromatography of amino acids in foods. i. : research on procedure of development studies on improvements in quantitative paper chromatography of amino acids in foods. ii.: selection of solvent systems determination of the equilibrium relative humidity of foods untersuchungen fiber die methodik der quantitativen bestimmung yon heizolen und flfissigen treibstoffen im wasser determination of ~-lactalbumin in complex systems hydrogen sulphide in cheddar cheese; its estimation and possible contribution to flavour ascorbic acid measurement. polarographic determination of total ascorbic acid in foods trans-fettsguregehalt yon sehweineschmalz nach fiitterung von schweinen mit rindertalghaltigem kraftfutter. (ein beitrag zur quantitativen infrarotspektroskopischen bestimmung yon trans-fetts~uren in fetten the importance of starch on the microscopic identification of cereal grains in feeds insecticide residues. chromatographic identification of some organophosphate insecticides in the presence of plant extracts chemical and biological estimation of the carotene content in fresh and processed italian apricots sialir acid as an index of the u-casein content of bovine skimmilk foodstuffs analysis. nonvolatile acids of blueberries le dosage de la matibre grasse dans les fromages. ]~tude critique de la m6thode en usage au laboratoire municipal la d6termination de residus d'insecticides et de fongieides par la m6thode polarographique fusel oil determination by gas.liquid chromatography * die brabanter mastitis-reaktion, ein neues verfahren zur ermittlung yon sekretionsstsrungen des euters dutch die kannenmilchuntersuchung uber eine enzymatisehe _&pfels~urebestimmung in wein und traubensaft direct microscopic technique to detect viable yeast cells in pasteurized orange drink die enzymatisehe bestimmung der glucose und saecharose und ibre anwendung in der lebensmittelanalyse a modified zirconium-alizarin method for determining fluoride in natural waters paper chromatography of some cholesterol derivatives determination of moisture by nuclear magnetic resonance and oven methods in wheat, flour, doughs, and dried fruits dye binding by soybean and fish meal as an index of quality the absorptiometrie determination of silicon in water: part l: formation, stability, and reduction of cr and fl-molybdosilicie acids column chromatography of soybean whey proteins enzymatic determination of carbon dioxide in lightly carbonated wines. 1962 collaborative study nachweis yon biiffelmilch als verf/flschungsmittel in kuhmilch durch serologisehe methoden photometric determination of phosphate in wines pertinent references to analytical lipid methods published recently, ft spectrophotometric estimation of nucleic acid of plant leaves hemmstoffe in der aalieferungsmilch und methoden zu ihrem nachweis determination of potassium in tobacco determination of chlorides in tebacco phospholipase c determination by egg yolk turbidimetry oher die inhaltsstoffe der rol]kastanie und versuche zu ihrer gehaltsbestimmung mierobiologlcal method for assaying nystatin in animal feeds /63] nr. 5, s. 401/415. --gaschromatographische untersuchungen yon fuselslen aus versehiedenen g~rproduk-ten. 2. mitt.: methodik der fusel61bestimmung lactose activity measurements. evaluation of laetase preparations for use in breadmaking comparison of methods for determination of lysino in cereals direct determination of calcium in plants, soils, and milk by means of a flame photometer colorimetrie determination of urea in feeds kolorimetrische bestimmung des dihydrox-yacetons fluoride, teeth, and the analyst the quantitative micro-determination of biphenyl in citrus fruit kolorimetrisehes verfahren zur gleichzcitigen bestimmung der weinsiiure und milchsiiurc in wein und most estimation of extra-cellular starch of dehydrated potatoes versuehe zur chromatographischen trennung yon kohlenhydra~en und eiweil3en aus dem w~ibrigen extrakt yon roggenvollkornmehl quantitative determination of the amino acid content of rumen fluid from twin steers fed soybean oil meal or urea vemnche zur chemischen differenzierung der eiwei•stoffe des weizens und roggens aromastoffe des brotes. versuch einer auswertung chemiseher gesehacksanalysen mit hilfe des schwellenwertes zur trennung yon sacchariden an kohle]celit~-s~ulen. ern~hrungs-fomchung 7 untersuehungen zur bestimmung der lsslichkeit yon milchpulver * selection of a medium for the isolation and enumeration of enterocoeei in dairy products colorimetric determination of amino nitrogen in corn syrups 0stxogene und versuche zu ihrem nachweis in gefliigelflelsch. dt. lebensmittel ein beitr~g bert. die verwendung der anatysen-q~arzlampe zu friihzeitiger erkennung der l~anzigkeit colorimetrlsche methode zur bestimmung yon 1-monoglyceriden in eiskrem determination of fusel oil in distilled spirits zu den m6glichen fehlerquellcn bei der histometrischen ermittlung des kollagen-, bzw. gelatine-gehaltes bei briihwiirsten studium der uv-spektren der auf hshere tempcraturen erhitzten 01e measuring of oil-binding characteristics of flour naehweis der konservierungsmittel mit hilfe cl~r papierehromatographie identification of ch]orogenic acid in castor bean and oranges. canad evaluation of forages in the laboratory. iii.: comparison of various methods for predicting silage digestibility feed microscopy essential oils. determination of botanical and geographical origin of spearmint oils by gas chromatographic and ultraviolet analysis fluorometric determination of chlortetracycline in premixes dfinnschicht-chromatographie yon carotin-und carotinoidgemischen measurement of the sub-sieve particle size distribution of flour chemisehe bestimmung der riickst~nde yon parathion, malathion und diazinon auf blumenkohl, kohlrabi, bohnen und gurken determination of cadmium anthranilate in feeds nachweis yon penicillin und anderen antibiotika in milch microbiological evaluation of protein quality with tetrahymenapyriformis w. 3.: a simplified assay procedure peanut lipoprotein. ii. : analysis in foods by gas chromatography beitrag zum papierchromatographisehen und spektrophotometrisehen i~achweis fettlsslieher synthetiseher farbstoffe in lebensmitteln und kosmetika elektroehemische sauerstoffbestimmung in olefinischen fetich bestimmung der gesamten sehwefligen s~ure in getr~nken the modified whiteside test. recommended procedures for bulk or blended milk deliveries die bestimmung yon mileheiweib in fleiseherzeugnisscn. dr. lebensmittel zur bestimmung des veresterungsgrades yon pektin a quantitative fluorometrie method for the determination of serpasil (reserpine) in feeds at the micro level fluorimetric mierodetermination of carbohydrates zur l~iethodik der klebrigkeitsbestimmung yon brot frage der papierchromatographischen untersuchung von amylopektin und amylose chemical determination of diethylstilbestrol residues in the tissues of treated chickens gas chromatographic identification of components in m~ple sirup fl~vor extract dark discoloration of canned all-green asparagus. ii. development of a new tin plate for its control thermal conductivity and density of chicken breast mnsele and skim beitrag zur bestimmung der fluoreszenz in spriten microbiological determination of alanine in proteins and foods collaborative study of the method for counting microorganisms in maple sirup glass fiber paper strip charring. a rapid and simple method for monitoring column chromatography of lipids verbesserte mcthode zum serienm~bigcn quantitativen nachweis yon insektizidrficksti~nden bei 0bst und gemfise use of the shear press in determining fibronsness of raw and canned green asparagus betrachtungen fiber verschiedene methodcn zur bestimmnng des bindegewebeanteiles in rohem fleisch und fleischwaren. arch. lebensmittel-hyg the determination of citric acid in milk and milk sera formaldehyde in maple sirup: an adaption of the nash method polarographische bestimmung dcr ascorbinsiiure und des gesamt-vitamin c untersuchungcn fiber die mbglichkeit zur objektiven beurteilung der organoleptischen eigensehaften yon kokosraspeln analysis of the flavor and aroma constituents of florida orange juices by gas chromatography assay for cyzine in finished feeds dfinnsehicht-ehromatographische trennnngen yon synthetischen lebensmitteffarbstoffen auf ceuulose-schichten evaluation of quantitative methods of determining peroxidase in vegetables. i.: the indophenol and the o-phenylenediamine methods ein beitrag zur untersuchung thermisch oxydierter fette. dt. lehensmittel a more accurate method for determination of caffeine in decaffeinated coffee bestimmung yon vitamin c in friichten, fruchtsiiften, gemiise und konserven naeh der methode naeh tillma~s unter ausschaltung reduzierender stoffe lebensmittelrecht und lebensmitteliiberwaehung nutritional laws and nutritional control briihwiirst~ einfaeher qualit~t, die zu einem kaliber unt~r 32 mm in den verkehr gebracht werden, sind i.s. des w 4 nr. 3 lmg irreffihrend aufgemaeht new regulations under the food and drugs act lebcnsmittel-rdseh orb der kenntlichmaehung fremder stoffe probleme des geltenden lebensmittelrechts glasurmittel ftir r6stkaffee beschr~nkt zugelassen food technol. 17 [1963] nr. 6, s. 96. n. iv. : revised u. k. preservatives regulations. food teehnol ausschub fiir lebeusmittelrechtliche fragen der fachgruppe lebensmittelehemio und gerichtliche chemic in der geseuschaft dcutscher chemiker vi. t~tigkeitsberieht der eidg. kommission fiir volksern~hrung, lebensmittelgesetzgebung und -kontrolle (eek) zu h~nden des eidg. departementes des i_nnern, umfassend die jahre federal food, drug, and cosmetic act, as amended. selected u. s. government publ. 1963 nr. 8; 50 h. catalog i~o verkauf yon frikadellen mit brotzusatz in gastwirtsehaften tierarzneimittel und aufzuchtmittel in der landwirtschaftlichen praxis. gesundheitliche erw~gungen zum schutze des konsumenten bei der anwendung yon tierarzneimitteln und aufzuchtmit~ln in der landwirtschaftliehen praxis. teil hi der amtsarzt und das neue lebensmitt~lgesetz. off ist der beschlub des bundesgerichtshofes vom 18. 5. 1962 -1 stl~ 546161 -geeignet, den vertrieb yon hackfleiseh befriedigend zu regeln ? arch. lebensmittel-hyg zur beurteilung des saccharingehaltes yon meerrettiehzubereitungen. dt. lebensmittel zum begriff ,mai]gebend" in w 4a abs. 2 des lebensmittelgesetzes aspect sanitaire et ldgal actuel des aliments conservds verbrauchererwaxtung und lebensmitte]kontrolle bei fleiseherzeugnissen bei ger~ueherten fleischwaren. sehwarz-w~lder speck, schwarzw~lder sehinkenspeck, sehwarzw~lder sehinken. arch. lebensmittel-ttyg kampf der wasserverseuchung. aktuelle notwendigkeiten -gesetzliehe ~/isgliehkeiten. ~iiinchener reed. wschr. 105 lebensmittelreehtliehe stellung yon carotin und carotinoiden in der schweiz die lebensmittelgesetzgebung 0sterreiehs, der sehweiz und der bundesrepublik deutschland. eine vergleiehende untersuchung arzneimittel-lebensmittel dr. lebensmittel-rdseh erwiderung des autors (zur stellungnahme yon f. nitzsc~, d~. lebensmittel-rdseh. 59 [1963] nr. 5, s. 146). i)t. lebensmittel das lebensmittelgesetz und seine auswirkung auf die gummiindtlstrie codex alimentarius austriacus absehliel]ende stellungnahme der ort der kenntlichmachtmg fremder stoffe. dr. lebensmittel-rdsch _rreffihrende bezeiehnung und angaben bei limonade aus mineralamem tafelwasser. dr. lebensmittel zur herkunftsbezeichnung yon lebensmitteln. dt. lebensmlttel aktuelles zur lebensmitteliiberwachung einige beispiele fiir die auswirkung der neuen lebensmittelrechtliehen vorschriften auf erniihrungs-und landwirtschaft auf dem wege zum einheitliehen lebensmittel-rech~ zur ~r yon b. rsssl~: welehe anforderungen sind an alkoholhaltige siigwaren zu stellen? dr die silbertmg yon tafelwiissern mokka-kaffee" auch im handel mit kaffeebohnen keine tterkunftsbezeiehnung 59 [1963] nr. 1, s. 29131. --zuliissigkeit trod grenzen bildlicher darstellungen yon fleiseh und ylelscherzeugnissen auf paclmngen yon suppen in trockener form. db. lebensmit~el-l~lsch bedeutung und beur~eitung yon galtstreptokokken in vorzugsmileh. arch. lebensmittel-hyg auf clipverschliissen zul~ssig ist die infektion mit trichinen aus amtlich untersuehtem schwelnefleiseh im lichte der mathematischen analyse der bestimmungen der fleischbesehau yon schweinefleiseh msglich? arch. lebensmittel-hyg intema~ionales rundgespr~ch fiber lebensmitte]ehemische probleme in wiesbaden und eltville a. rh. z. lebensmittel-untersuch. u. -forschung. 129 [1963] nr. 2, s. 1271130. --kommission zur priifung fremder stoffe bei lebensmitteln (fremdstoff-kommission) der deutsehen forsehungsgemeinsehaft entwicklung des lebensmittelrechts im nationalen und internationalen bereich entwicklung des lebensmittelrechts im nationalen und inter~ationalen bereich entwicklung des lebensmittelrechts im nationalen und internationalen bereich de warenwet en de hierop berustendc besluiten zum entwurf einer harmonisierung der lebensmittelrechtlichen bestimmungen fiber konservierungsstoffe im gebiet der europaischen wirtschaftsgemeinschaft. er lebensmittelrechtliche stellung yon carotinen und carotinoiden in der bundesrepublik deutschland die instrumente der lebensmittelfiberwachung in osterreich 0sterreichischer standpunkt zur l~rage der f~rbung yon lebensmitteln mit carotinen und carotinolden. wiss. ver6ff. dr. ges. ernkhrung 9 lst es zu vcrtreten, dab das fleisch schwacbfinniger rinder auch in gebr~tetem zustand eingefroren wird? z lrch. lebensmittel-iiyg richtlinien fiber die zulassung yon gegeusachverst~ndigen zur untersuchung yon lebensmittel-gegenproben die ]ebensmittelrechtliche bedeutung yon bildiichen darstellmlgen auf verpackungen diverse problems (education, documentation associations, terminology etc the nutritional education of the food technologist proposed formation of a food engineering panel within the food group studium der hauswirtschafts-und ern~hrungswissenschaften. ern~hrungswirt-sehaft l0 an information service for the american food industry 1st international congress of food science and technology. symposium on education and training technically trained people for developing countries lft paces the food frontier un committee on food additives international standardization of fruit and vegetables. food technol terminology and methods for feeding and weighing animals food additives and food standards beitriige zur durehffihrung der umweltsradloaktivitiits-0berwaehung training dairy personnel in denmark training opportunities for the sanitarian-specialized in-service training r die benennungen honigkueheniihnlicher oebiieke als lobkuehen und lebzelten sowie als biber und bibenzelten. dt. lebensmittel nutrition and dietetics for the medical student problem of keeping dairy plants supplied with the foreman-type employee literaturdokumentation fiir hochschulassistenf~n a system for naming and describing feeds, energy terminology, and the use of such information in calculating diets a brief sketch of veterinary periodical literature in great britain before the foundation of the veterinary record a conference on nutrition teaching in medical schools the food service industry and its relation to the control of foodborne illness research and educational progress in nutrition informationsm6gliehkeiten fiir tieriirzte auf dem measuring readability of health education literature the dai~y literature problem the central food technological research institute the education and function of the nutritionist training in food service for nursing homes. l: tools for evaluation training in food service for nursing homes. iii.: observations on management of twelve units pennsylvania takes a look at nutrition in the orthopedic program zur definition der begriffe ,aroma" und l~ber die notwendigkeit einer priifung for beamtete sehlaehthofleiter. arch. lebensmittel-hyg organisation der dokumentation in einem forschungsinstitut (bundes. forsehungsanstalt f'tir lebensmittelfrischhaltung in karlsruhe). dt. lebensmittel-rdsch on changing the name of our assoziation. for a name change 0pporbunities in nutrition education questionnaires to identify nursing homes most in need of dietary counsel. publ. health irep lebensmittelwissenschafttiche institute in bulgarien zur stellung des psychiaters in der alkoholfrage naas nutrition chemists. vcter on changing the name of our association. against a name changing begriffe) in 10 sprachen: deutseh, russiseh, polnisch, tsehechisch, slowakisch, ungariseh, bulgariseh, serbokroatiseh, rum~nisch, englisch the role of nutrition in the teaching of medicine key: cord-026028-qj290zu6 authors: nan title: spezielle arzneimitteltherapie in der schwangerschaft date: 2008-12-10 journal: arzneiverordnung in schwangerschaft und stillzeit doi: 10.1016/b978-343721332-8.50004-1 sha: doc_id: 26028 cord_uid: qj290zu6 nan wie die meisten anderen medikamente ist auch paracetamol plazentagängig. anfänglich wurde aufgrund einzelner fallberichte ein teratogenes potenzial beim menschen vermutet. auch in den vergangenen jahren wurden toxische auswirkungen auf das ungeborene diskutiert: eine assoziation von gastroschisis mit einer mütterlichen kombinationsmedikation aus paracetamol und pseudoephedrin im 1. trimenon fanden werler und mitarbeiter (2002) bei retrospektiver auswertung von 206 erkrankten säuglingen. kein zusammenhang konnte zwischen mütterlicher paracetamoleinnahme und ventrikelseptumdefekten festgestellt werden (cleves 2004) . eine neuere studie diskutiert ein möglicherweise erhöhtes risiko von paracetamol in der spätschwangerschaft für asthma bronchiale erhöhte ige-spiegel im vorschulalter (shaheen 2005 , shaheen 2002 . abgesehen von methodischen mängeln der studie erscheint dieser zusammenhang biologisch wenig plausibel. alle vorliegenden daten zusammengefasst, gibt es beim menschen keine ernsthaften hinweise auf teratogenität (übersicht in . zur überdosis bei suizidversuchen siehe kapitel 2.22.4.10. die an lymphozyten beobachteten diskreten genotoxischen effekte (hongslo 1991) scheinen keine klinische relevanz zu besitzen. empfehlung für die praxis: paracetamol ist das analgetikum und antipyretikum der wahl. es kann in jeder phase der schwangerschaft innerhalb des üblichen dosisbereichs eingesetzt werden. die thrombembolieprophylaxe genutzt. die analgetische, antipyretische und antiphlogistische wirkung erfolgt über eine hemmung der prostaglandinsynthese bei einzeldosen ab 500 mg. aufgrund der geringen therapeutischen breite im antiphlogistischen bereich (tagesdosen von 3.000 mg und darüber) wurde acetylsalicylsäure als antirheumatikum weitgehend durch die neueren, nichtsteroidalen antirheumatika (nsar) verdrängt. salicylate sind lipophil, sie werden nach oraler gabe rasch resorbiert und gelangen leicht über die plazenta zum fetus. die metabolisierung und eliminierung durch kopplung an glucuronsäure in der leber erfolgt beim fetus und beim neugeborenen nur langsam wegen der noch verminderten enzymaktivität und der geringen glomerulären filtrationsrate. "low-dose"-therapie. niedrig dosiert mit 80-300 mg pro tag wird acetylsalicylsäure als thrombozytenaggregationshemmer zur thrombembolie-prophylaxe eingesetzt und in manchen fällen zur prävention einer präeklampsie verordnet. außerdem diskutiert man den nutzen niedriger dosen zur prävention von abortneigung und anderen schwangerschaftskomplikationen bei frauen mit anti-kardiolipin-oder anti-phospholipid-antikörpern mit oder ohne systemischem lupus erythematodes (backos 1999) . in einer prospektiven studie mit jeweils 101 schwangeren in fall-und kontrollgruppe, mit mindestens 2 aborten in der anamnese bzw. nachweisbaren autoantikörpern konnte keine verringerung der abortrate unter acetylsalicylsäure in kombination mit prednison im vergleich zu placebo festgestellt werden. es fand sich jedoch in der behandlungsgruppe ein signifikant höheres risiko für eine frühgeburt (laskin 1997) . eine meta-analyse fand gegenüber placebo ebenfalls keine reduzierung des abortrisikos, aber ein signifikant geringeres risiko für eine frühgeburt (kozer 2003 , kozer 2002 . eine erhöhung der schwangerschaftsrate durch eine kombinierte therapie mit prednison und acetylsalicylsäure konnte bei kinderwunschpatientinnen mit nachweisbaren autoantikörpern und wiederholt erfolglosen in-vitro-fertilisationen (ivf) erzielt werden (geva 2000 , geva 1998 . die untersuchung einer vergleichbaren therapie bei patientinnen mit intrauteriner insemination (iui) konnte dieses ergebnis beim vergleich mit einer nicht behandelten gruppe bestätigen (hsieh 2000) . viele untersuchungen haben sich mit dem nutzen einer "low-dose"-behandlung zur prävention einer plazentationsstörung mit daraus resultierendem schwangerschaftshochdruck und intrauteriner wachstumsverzögerung beschäftigt. umfassend wurde dieses thema von der "collaborative low-dose aspirin in pregnancy study" (clasp 1994 ) an insgesamt 9.000 frauen untersucht. im gegensatz zu früheren ergebnissen sind eindeutige vorteile wohl nur bei schwangeren mit einer sich früh entwickelnden präeklampsie -vor 20 schwangerschaftswochen (ssw) -und mit pathologischer vorgeschichte zu erwarten. ren und wurden durch paracetamol und andere analgetika verdrängt. pyrazolon-und phenylbutazonverbindungen besitzen eine prostaglandinantagonistische wirkung, die ab schwangerschaftswoche 28-30 einen vorzeitigen ductus-arteriosus-verschluss beim fetus auslösen kann. ein fallbericht beschreibt eine schwangere, die aufgrund einer nierenkolik kurz vor ende der schwangerschaft hoch dosiert mit metamizol behandelt wurde und darunter ein oligohydramnion entwickelte (catalan 1995) . eine brasilianische studie berichtet über einen von anderen autoren bisher nicht bestätigten zusammenhang zwischen metamizol-einnahme durch die mutter und dem vermehrten auftreten von wilms-tumoren bei den kindern (sharpe 1996) . in einer retrospektiven studie hatte bei kindern mit akuter leukämie im alter von x 18 monaten ein höherer anteil der mütter metamizol in der schwangerschaft eingenommen als in der gesunden kontrollgruppe. daraus wurde ein signifikant erhöhtes risiko für eine frühkindliche leukämie nach metamizol-therapie in der schwangerschaft abgeleitet (alexander 2001) . diese schlussfolgerung sollte jedoch aufgrund der geringen fallzahl und der unzureichenden informationen über den zeitpunkt der exposition sehr kritisch bewertet werden. im übrigen liegen keine hinweise auf embryotoxische eigenschaften beim menschen vor. eine prospektive untersuchung von 108 im 1. trimenon mit metamizol behandelten schwangeren fand im vergleich zur kontrolle kein signifikant erhöhtes risiko für große fehlbildungen (bar-oz 2005) . dieses ergebnis kann nach sichtung von 154 eigenen prospektiv erfassten metamizol-expositionen im 1. trimenon bestätigt werden. zu propyphenazon liegen in unserer eigenen datenbank 34 prospektiv erfasste fälle mit mütterlicher therapie im 1. trimenon vor. von diesen schwangerschaften endeten 3 mit abbruch, 8 mit einem spontanabort und 23 mit einer lebendgeburt. es fand sich eine große fehlbildung (neuralrohrdefekt) bei einem abortierten fetus. insgesamt ergibt sich daraus kein anhalt für ein teratogenes risiko. zu phenazon und propyphenazon liegen keine ausreichend dokumentierten erfahrungen zur anwendung in der schwangerschaft vor. phenylbutazon (z. b. ambene ® ) und verwandte verbindungen wie famprofazon, kebuzon, mofebutazon (z. b. mofesal ® ) und oxyphenbutazon sind schwache analgetika und antipyretika, die über eine hemmung der prostaglandinsynthese stark antiphlogistisch wirken. phenylbutazon ist bei morbus bechterew indiziert. phenylbutazonverbindungen können die blutbildung schädigen, sie führen zu einer flüssigkeitsretention und kumulieren stark (halbwertszeit 30-170 stunden). diese eigenschaften sind in der schwangerschaft unerwünscht. im tierversuch wirkt phenylbutazon teratogen. zur beurteilung embryotoxischer effekte beim menschen liegen keine ausreichenden daten vor, ein erhebliches teratogenes potenzial erscheint unwahrscheinlich. durch den prostaglandinantagonismus können phenylbutazonverbindungen ebenso wie acetylsalicylsäure und andere nsar einen vorzeitigen verschluss des ductus arteriosus verursachen, wenn nach woche 28-30 behandelt wird (überblick in . empfehlung für die praxis: auf den einsatz von metamizol, phenazon und propyphenazon sollte verzichtet werden. analgetikum der wahl ist paracetamol, in bestimmten fällen auch in kombination mit codein. nach heutiger kenntnislage ergibt sich aus einer dennoch erfolgten exposition mit einem der genannten mittel im 1. trimenon keine risikosituation, die weitergehende diagnostik erfordert oder in der ein risikobegründeter abbruch einer gewünschten und intakten schwangerschaft erwogen werden müsste (siehe kapitel 1.15 ). zusätzliche untersuchungen wie dopplersonographische kontrollen des ductus arteriosus sollten eingeplant werden, wenn mit diesen medikamenten nach woche 30 behandelt wurde. g 2.1.5 opiate sind zentral wirksame, starke analgetika, die in ihrer wirkung dem morphin, dem hauptalkaloid des opiums, vergleichbar sind und ebenfalls zur abhängigkeit und beim neugeborenen zu atemdepression und entzugssymptomatik führen können. bei den opiaten unterscheidet man reine agonisten (endorphine, morphin und therapeutisch ähnliche opiate) von reinen antagonisten (naloxon) und stoffen, die sowohl agonistische als auch antagonistische eigenschaften besitzen (pentazocin). hinsichtlich des toxischen potenzials in der schwangerschaft ist die kurzfristige therapeutische gabe von opiaten, z. b. in der perinatalphase, anders zu bewerten als der opiatabusus (siehe auch abschnitt 2.21.10). körpereigene endorphine reagieren spezifisch mit opiatrezeptoren und können morphinwirkungen auslösen. systematische untersuchungen zur teratogenität von morphin (z. b. capros ® ) oder hydromorphon (z. b. dilaudid ® ) liegen nicht vor. es gibt jedoch bislang keine hinweise, dass diese substanzen fehlbildungen beim menschen verursachen. ein fallbericht mit intrathekaler langzeitbehandlung mit morphin wegen chronischer schmerzen beschreibt ein gesundes neugeborenes mit normalen apgar-werten, ohne entzugssymptomatik und normaler entwicklung im alter von 18 monaten (oberlander 2000) . bei 5 prospektiv erfassten fällen mit langzeitbehandlung aus dem eigenen datenbestand finden sich 3 frühgeborene sowie ein reif geborenes kind mit entzugssymptomatik. fehlbildungen waren nicht nachweisbar. die einmalige intramuskuläre applikation von 10-15 mg morphin nach 18 schwangerschaftswochen führte zu einer reduzierung der fetalen atembewegungen bei insgesamt nicht reduzierten kindsbewegungen. es wurde ein fetal-mütterlicher plasmaquotient von 0,6 ermittelt ( kopecky 2000) . appliziert. in der nabelschnur finden sich 30-50 % der mütterlichen plasmakonzentration. bei ausreichendem zeitlichem abstand zur entbindung scheint das risiko einer neonatalen atemdepression gering zu sein. im vergleich zu einer kontrollgruppe fanden sich bei den kindern von 137 mit fentanyl behandelten müttern keine unterschiede bei atemdepression, apgar-score, naloxonbedarf sowie verschiedenen neurologischen parametern bis zu 24 stunden nach geburt (rayburn 1989) . die letzte fentanyldosis wurde in dieser untersuchung im durchschnitt 112 minuten vor der entbindung gegeben. in einer weiteren publikation waren in einer gruppe von 15 neugeborenen ebenfalls weder atemdepression noch neurologische abweichungen in den ersten 24 stunden nach der geburt zu beobachten. die applikation von fentanyl erfolgte jeweils etwa 10 minuten vor der schnittentbindung (eisele 1982) . die reif geborenen, gesunden neugeborenen von 101 frauen, die unter der geburt fentanyl epidural erhielten, zeigten keine atemdepression. die autoren diskutieren, dass eine epiduralanästhesie mit fentanyl im hinblick auf den stillerfolg der kinder wahrscheinlich günstiger ist als eine i.v.-applikation im rahmen einer allgemeinnarkose (jordan 2005) . andere untersucher beobachteten, dass eine patientenkontrollierte analgesie mit fentanyl i.v. unter der geburt gleich gut verträglich für das neugeborene ist wie eine epiduralanästhesie (nikkola 1997) . ein fallbericht beschreibt die anwendung von fentanylpflastern mit einer transdermalen dosis von ca. 125 ? g/stunde während der gesamten schwangerschaft. das gesunde reif geborene kind wies normale apgar-werte auf. nach 24 stunden entwickelte sich jedoch eine leichte entzugssymptomatik mit übererregbarkeit und schreiattacken, die nach 4 tagen abgeklungen war. die kindlichen blutspiegel wiesen unmittelbar nach der geburt ein drittel der mütterlichen werte auf und einen tag nach entbindung nur noch 9 % ( regan 2000) . weder unsere eigenen daten zu 22 frauen mit fentanylexposition im 1. trimenon noch beobachtungen anderer autoren ergeben hinweise auf teratogenität. fentanyl wurde in fetalen organen in der frühschwangerschaft nachgewiesen (cooper 1999) . mehrere veröffentlichungen beschreiben die intravenöse und epidurale anwendung von alfentanil (rapifen ® ) in der geburtshilfe (übersicht bei briggs 2005, gin 2000) . die verträglichkeit für das neugeborene scheint der des fentanyls zu gleichen. ein untersucher hat geringe neuromuskuläre funktionsabweichungen in den ersten 30 minuten nach geburt ermittelt, in der nabelschnur betrug die konzentration ca. 30 % der mütterlichen werte. in einigen neueren studien wurde remifentanil zur schmerzreduktion unter der geburt eingesetzt. dabei wurde in einer der studien über häufige therapieabbrüche wegen starker nebenwirkungen bei der mutter berichtet, wie z. b. übelkeit, erbrechen, atemdepression oder juckreiz. nebenwirkungen beim neugeborenen fanden sich in keiner der studien (übersicht in . die anwendung von sufentanil zur analgesie bei 351 frauen unter der geburt ergab eine deutlich geringere rate an hypotonien im vergleich zu anderen analgesieverfahren, aber signifikant mehr schwankungen der fetalen herzfrequenz bzw. eine häufiger auftretende fetale bradykardie (van de velde 2001) . berichte über teratogene effekte liegen weder für alfentanil vor noch für remifentanil (ultiva ® ) und sufentanil (sufenta ® ). für eine endgültige bewertung des teratogenen risikos sind die vorliegenden daten jedoch unzureichend. empfehlung für die praxis: bei gegebener indikation dürfen fentanyl und ggf. auch die anderen präparate in jeder phase der schwangerschaft eingesetzt werden. bei verabreichung kurz vor der entbindung muss wie bei allen analgetika vom opiattyp mit einer atemdepressiven wirkung beim neugeborenen gerechnet werden. bei rückenmark-nahen analgesieverfahren sind auswirkungen auf den kreislauf der mutter (hypotonie) zu vermeiden. g 2. 1.9 andere narkoanalgetika und zentral wirksame analgetika pharmakologie und toxikologie. pentazocin (fortral ® ) wurde (in den usa) in kombination mit dem antihistaminikum tripelenamin unter dem namen t's and blues als intravenös injizierbare droge gehandelt. tierexperimentell erwies sich diese kombination als nicht teratogen. intrauterine wachstumsverzögerung und verhaltensauffälligkeiten sind jedoch bei ratten nach pränataler applikation gehäuft aufgetreten. vergleichbare effekte haben sich auch beim menschen nach gebrauch dieser droge gezeigt. berichte zur therapeutischen anwendung fehlen. bei wiederholter einnahme bis zum ende der schwangerschaft muss mit opiattypischen entzugssymptomen gerechnet werden, wie z. b. unruhe, zittrigkeit, muskelhypertonus, diarrhö und erbrechen. pentazocin kann den uterustonus erhöhen (übersicht in . pentazocin hat sich ebensowenig wie tilidin (in valoron n ® ) gegenüber pethidin in der geburtshilfe durchsetzen können. hinweise auf ein teratogenes potenzial beim menschen gibt es zu beiden substanzen bisher nicht. tramadol (z. b . tramal ® ) ist in deutschland eines der meistverschriebenen opioidanalgetika. seine analgetische wirkung entspricht der von codein und liegt damit bei einem zehntel der wirkstärke vom morphin. im gegensatz zu morphin hat es in äquianalgetischen dosen jedoch keine deutliche atemdepressive wirkung. tramadol wird von drogenabhängigen missbraucht. bei der anwendung unter der geburt war tramadol sowohl hinsichtlich der schmerzreduktion als auch der mütterlichen nebenwirkungen dem pethidin unterlegen. unterschiede in der neonatalen entwicklung fanden sich jedoch nicht (keskin 2003) . in einer meta-analyse der cochrane database gab es keinen unterschied in der wirksamkeit beider substanzen ( elbourne 2000) . in unserer datenbank befinden sich 94 prospektiv erfasste schwangerschaften mit tramadoltherapie im 1. trimenon. unter den 78 lebendgeborenen hatten 5 kinder große fehlbildungen (6,4 %), davon 2 vorhofseptumdefekte, eine transposition der großen gefäße, eine meningomyelozele mit hydrozephalus und spina bifida und ein kind mit angeborenem katarakt und mikrophthalmus. in mindestens einem fall hatte die mutter zusätzlich teratogene medikamente (u. a. carbamazepin) eingenommen. ein verdacht auf embryotoxische effekte lässt sich mit diesen daten nicht untermauern, zumal von anderer seite bisher weder zu tramadol noch zu anderen opioidanalgetika substantielle hinweise auf teratogenität beim menschen geäußert wurden. über embryotoxizität wurde bisher auch nicht im zusammenhang mit buprenorphin (temgesic ® ; siehe kapitel 2.21.10), dextropropoxyphen, flupirtin (katadolon ® ), meptazinol (meptid ® ), nalbuphin (nubain ® ), nefopam (z. b. silentan ® ) und piritramid (dipidolor ® ) berichtet. systematische untersuchungen zur teratogenität fehlen jedoch. alle morphinähnlichen opiate können abhängig von behandlungsintervall und dosis zur atemdepression beim neugeborenen und zu entzugserscheinungen führen. dies gilt insbesondere für die substitution nach drogenabusus (siehe auch abschnitt 2.21.10). neonatale entzugserscheinungen können ebenso wie beim heroin ggf. erst verzögert einsetzen. empfehlung für die praxis: bei entsprechender indikation kann mit erprobten vertretern aus dieser arzneigruppe wie tramadol oder auch buprenorphin in der schwangerschaft behandelt werden. als schmerzmittel sollten jedoch paracetamol (ggf. mit codein) oder (bis woche 30) ibuprofen bevorzugt werden. nach heutiger kenntnislage ergibt sich aus einer exposition mit anderen in diesem abschnitt genannten mitteln keine risikosituation, die weitergehende diagnostik erfordert oder einen risikobegründeten abbruch einer gewünschten und intakten schwangerschaft (siehe kapitel 1.15). g 2.1.10 naloxon pharmakologie und toxikologie. naloxon (z. b. narcanti ® ) ist in der lage, die atemdepressorische wirkung von opiaten aufzuheben. bei kindern, deren mütter in der schwangerschaft opiatabusus betrieben haben, kann naloxon entzugserscheinungen verursachen. ein teratogenes potenzial wurde beim menschen bisher nicht beschrieben. den sich 6 große fehlbildungen, darunter 3 vorhofseptumdefekte, einmal kombiniert mit einer pulmonalklappenstenose, sowie eine spina bifida, eine lippen-gaumen-spalte und eine komplexe skelettfehlbildung. zusammenfassend ergibt sich daraus kein anhalt für ein erhöhtes abort-oder gesamtfehlbildungsrisiko. systematische studien zur anwendung von indometacin im 1. trimenon liegen nicht vor. eigene daten umfassen 172 prospektiv erfasste schwangerschaften mit diclofenac-therapie im 1. trimenon, von denen 22 mit einem abbruch, 15 mit einem spontanabort und 135 mit einer lebendgeburt endeten. große fehlbildungen fanden sich in 6 fällen, darunter 2 vorhofseptumdefekte, ein hydrozephalus, eine doppelanlage der niere, eine nierenagenesie und beidseitiger klumpfuß. daraus lässt sich kein anhalt für ein erhöhtes fehlbildungsrisiko ableiten. für naproxen im 1. trimenon fand sich in retrospektiven analysen mit daten des schwedischen geburtsregisters ein leicht erhöhtes risiko für spaltbildungen bei nicht erhöhtem gesamtfehlbildungsrisiko (ericson 2001) und ein ebenfalls leicht erhöhtes risiko für kardiovaskuläre fehlbildungen (källén 2003) . ein fallbericht beschreibt ein neugeborenes mit großer beidseitiger lippen-und gaumen-spalte, hypertelorismus, breiter nasenwurzel, tiefem ohransatz sowie asymmetrischem fehlen von endphalangen beider füße nach mütterlicher therapie mit bisoprolol, naproxen und sumatriptan bis woche 5 (kajantie 2004). der expositionszeitraum spricht gegen einen ursächlichen zusammenhang. von den durch uns prospektiv erfassten 10 fällen mit naproxentherapie im 1. trimenon endeten 2 schwangerschaften mit einem spontanabort, die 8 lebendgeborenen waren gesund. spontanaborte. zwei studien beschreiben ein erhöhtes abortrisiko durch die einnahme nichtsteroidaler antiphlogistika , nielsen 2001 . die geringe fallzahl beider studien lässt deren aussage jedoch fraglich erscheinen. des weiteren werden in einer dieser arbeiten lediglich rezeptierungen registriert ohne angabe zur tatsächlichen einnahme des medikamentes. eine genaue angabe der substanzen fehlt in beiden publikationen. auswirkungen auf den kreislauf und andere organsysteme beim fetus. im letzten drittel der schwangerschaft können nichtsteroidale antirheumatika (nsar) zum vorzeitigen verschluss des ductus arteriosus beim fetus führen (mas 1999) . eine mekoniumanalyse bei neugeborenen zur klärung eines möglichen zusammenhanges zwischen nsar und persistierendem pulmonalen hypertonus (pphn) fand bei neugeborenen mit pphn mehr als doppelt so häufig nsar im mekonium (ibuprofen, naproxen, indometacin sowie acetylsalicylsäure) als bei gesunden kindern (alano 2001) . je reifer der fetus, desto größer ist die wahrscheinlichkeit, dass sich sein ductus arteriosus unter der antiphlogistischen therapie schließt (rasanen 1995) . schon von schwangerschaftswoche 27 an wurde dieser effekt beobachtet (bivins 1993) . vor woche 32 soll der fetale kreislauf nur in 5-10 % der fälle ansprechen, mit 32 wochen in 50% und ab woche 34 in 100% der fälle (moise 1993 (moise , 1988 . auch ein scheinbar paradoxer effekt wurde nach pränataler exposition mit nsar bei neugeborenen beobachtet: ein persistierender ductus arteriosus. dieser musste operativ verschlossen werden (norton 1993) . von den autoren wurde postuliert, dass indometacin in diesem fall die intima des ductus geschädigt und damit den spontanverschluss verhindert hat. aus einem vorzeitigen ductusverschluss kann sich ein pulmonaler hypertonus beim neugeborenen entwickeln, wie z. b. bei einem reifen kind, dessen mutter 2 wochen vor entbindung wegen einer thrombophlebitis außer heparin täglich 75 mg diclofenac für 5 tage erhalten hatte. der pulmonale hypertonus persistierte und musste 22 tage lang mit hohen dosen no-inhalation behandelt werden. ein offenbar ischämisch verursachter trikuspidalklappenreflux blieb auch danach bestehen (zenker 1998) . ein weiterer fall mit pulmonalem hypertonus wurde bei einem neugeborenen mit geschlossenem ductus arteriosus beschrieben, das in woche 39 auf grund einer fetaler bradykardie per sectio entbunden wurde. die mutter war drei tage zuvor mit diclofenac therapiert worden (siu 2004) . in einem weiteren fall mit zweimal täglich 220 mg naproxen innerhalb der letzten 4 tage vor entbindung entwickelte ein reif geborenes kind 2 stunden nach geburt einen pulmonalen hypertonus bei rechtsherzhypertrophie und geschlossenem ductus arteriosus. die symptomatik normalisierte sich unter sauerstofftherapie bis zum 2. lebenstag. nach 5 monaten war das kind klinisch gesund, bei leichter echokardiographisch noch nachweisbarer rechtsherzhypertrophie (talati 2000) . auch die fetale und neonatale nierenfunktion kann bis zur anurie gehemmt werden, wenn im letzten drittel der schwangerschaft mit einem nsar behandelt wurde. dieser effekt wird auf eine minderperfusion der niere und einen anstieg des zirkulierenden vasopressin zurückgeführt (van der heijden 1994 , walker 1994 . ebenfalls durch minderperfusion beim fetus werden die bei neugeborenen nach pränataler nsar-exposition beobachteten fälle von nekrotisierender enterokolitis (nec) erklärt (ojala 2000 , parilla 2000 , major 1994 , norton 1993 . nierenfunktionsstörungen und nec traten auch bei neugeborenen auf, bei denen man den persistierenden ductus arteriosus nach der geburt mit indometacin verschließen wollte. schließlich wurden auch intrakranielle blutungen besonders bei frühgeborenen beschrieben, möglicherweise als folge einer durch indometacin induzierten hemmung der thrombozytenaggregation (norton 1993) . es ist anzunehmen, dass die exemplarisch beschriebenen organstörungen beim fetus nach gabe aller nsar auftreten können (z. b. ductusverschluss bei ketoprofen und nifluminsäure; radi 1999 , llanas 1996 . beim vorwiegend als cox-2-hemmstoff wirkenden nimesulid wurde in zwei kasuistiken über (dialysepflichtiges) nierenversagen beim kind berichtet, nachdem die mutter in der spätschwangerschaft behandelt worden war. im zweiten fall waren es 200 mg/tag zur tokolyse von woche 26 bis 32 ( balasubramaniam 2000 , peruzzi 1999 . bei einem in woche 33 geborenen kind wurde ein akutes nierenversagen beschrieben nach feststellung eines oligohydramnions in woche 30 und bereits im 1. trimenon, also vor der "sensiblen phase" erfolgter therapie mit nimesulid, diclofenac und paracetamol (benini 2004) . eine weitere kasuistik beschreibt ein kind mit chronischer nierenschädigung nach vierwöchiger nimesulidtherapie der mutter ab woche 30, bei der bereits 2 wochen nach therapiebeginn ein oligohydramnion diagnostiziert wurde. eine konservative therapie war noch im alter von 20 monaten erforderlich (magnani 2004) . holmes und mitarbeiter (2000) berichten ebenfalls über ein oligohydramnion, welches 3 wochen nach einer in woche 24 begonnenen nimesulidtherapie zur wehenprophylaxe auffiel und sich nach ende der therapie wieder normalisierte. das reif geborene kind war gesund. ein ähnliches ergebnis fand sich in einem bericht über 5 schwangerschaften mit nimesulidtherapie wegen vorzeitiger wehen. alle frauen entwickelten ca. 3 tage nach therapiebeginn ein oligohydramnion, welches sich nach behandlungsende zurückbildete. keines der kinder wies eine manifeste nierenschädigung auf (locatelli 2001) . in einer prospektiven studie entwickelte rund die hälfte der 44 frauen, die eine nimesulidtherapie zur prophylaxe vorzeitiger wehen erhielten, nach ca. vierwöchiger therapie ein oligohydramnion, welches sich nach therapieende wieder zurückbildete. in einem fall mit akutem nierenversagen des frühgeborenen hatte die mutter die vorgeschriebenen kontrolluntersuchungen nicht wahrgenommen. in keinem fall war eine beendigung der therapie wegen verschluss des ductus arteriosus erforderlich (sawdy 2004) . paladini (2005) beschreibt 10 fälle mit verschluss des ductus ateriosus beim neugeborenen nach einnahme von maximal 2 analgetischen einzeldosen kurz vor der geburt (paladini 2005) . andere untersucher fanden keine nebenwirkungen beim neugeborenen nach tokolyse mit sulindac bei 10 schwangeren in woche 28-32 (sawdy 2003) . sulindac soll aufgrund der geringen plazentagängigkeit seines aktiven (sulfid-)metaboliten keine dopplersonographisch feststellbaren veränderungen auf den fetalen kreislauf besitzen (carlan 1995 und 1992 , kramer 1995 . dieser vorzug gegenüber anderen nsar wird in anderen publikationen nicht bestätigt (kramer 1999) . schwangerschaften wurde eine abgebrochen und 4 endeten mit der geburt eines gesunden kindes (eigene daten). eine kleine randomisierte studie fand keine unterschiede beim tokolytischen effekt zwischen celecoxib und indometacin. im gegensatz zu indometacin waren unter celecoxib kein partieller vorzeitiger verschluss des ductus arteriosus und auch keine verminderung der amnionflüssigkeit nachweisbar (stika 2002) . beim randomisierten vergleich von rofecoxib und magnesiumsulfat war weder in der effektivität der tokolyse noch hinsichtlich neonataler nebenwirkungen ein unterschied feststellbar (mcworther 2004) . für eine endgültige aussage sind die fallzahlen zu gering. man kann davon ausgehen, dass die bei den klassischen nsar und acetylsalicylsäure beschriebenen fetotoxischen wirkungen in der spätschwangerschaft auch bei den cox-2-inhibitoren zu erwarten sind. in einer kleinen randomisierten studie fand man nach rofecoxib-einnahme im vergleich zu placebo eine verspätete follikelruptur. das könnte ein hinweis für eine mögliche herabsetzung der fertilität bei einnahme von rofecoxib zum konzeptionszeitpunkt sein -ein effekt, der auch im zusammenhang mit anderen nsar schon erörtert wurde (pall 2001) . die vorliegenden daten zu coxiben in der schwangerschaft erlauben keine differenzierte risikobewertung. empfehlung für die praxis: selektive cox-2-inhibitoren sind aufgrund mangelnder erfahrung in der schwangerschaft zu meiden. nach heutiger kenntnis ergibt sich aus einer dennoch erfolgten exposition im 1. trimenon keine risikosituation, die eine invasive diagnostik erfordert oder einen risikobegründeten abbruch einer gewünschten und intakten schwangerschaft (siehe kapitel 1.15 ). eine ultraschallfeinuntersuchung sollte zur bestätigung der normalen entwicklung des fetus angeboten werden. g 2. 1 man unterscheidet zwischen der medikamentösen migräneprophylaxe und der behandlung einer migräneattacke. die pathophysiologie der attacke verläuft in drei phasen: 7 prodromalstadium mit vasokonstriktion der gefäße der betroffenen hirnhälfte, 7 schmerzstadium mit vasodilatation, 7 ödemstadium, das mit einer erhöhten gefäßpermeabilität einhergeht und lange anhalten kann. zur medikamentösen therapie gibt es unterschiedliche ansätze. die im folgenden angeführten mittel werden zum teil an anderer stelle in diesem buch detailliert erörtert. generell werden zur medikamentösen prophylaxe und therapie der migräne die folgenden, mit einschränkungen auch in der schwangerschaft akzeptablen mittel empfohlen (göbel 1999) . keines der angegebenen medikamente steht in verdacht, beim menschen teratogen zu wirken. allerdings sind beispielsweise cyclandelat und flunarizin bisher unzureichend untersucht. die zur migräneprophylaxe empfohlenen dosen von betarezeptorenblockern (metoprolol und propranolol) können auch beim fetus zu einer relativen bradykardie führen. diese ist nicht bedrohlich, kann aber falsch interpretiert werden, wenn die medikation nicht bekannt ist. metoprolol, propranolol, cyclandelat, flunarizin, acetylsalicylsäure, magnesium, amitriptylin, naproxen (nicht nach woche 30) baclofen während der gesamten schwangerschaft verabreicht. alle kinder waren gesund und wiesen keine entzugssymptomatik auf (roberts 2003, munoz 2000) . zur baclofen-therapie per os über den gesamten zeitraum der schwangerschaft, bei der wesentlich höhere dosierungen benötigt werden, gibt es 2 kasusistiken (dosis 20-80 mg/ tag). beide neugeborenen wiesen keine fehlbildungen, aber eine entzugssymptomatik auf. diese äußerte sich in einem fall in krampfanfällen am 7. lebenstag (ratnayaka 2001) . beim anderen neugeborenen wurden kurz nach der entbindung übererregbarkeit und atembeschwerden beschrieben (moran 2004) . aus eigener beobachtung können wir über 2 gesunde neugeborene nach oraler baclofen-therapie im 1. trimenon berichten. nach behandlung mit chlormezanon in der schwangerschaft wird über eine fulminant verlaufende hepatitis mit lebertransplantation und der anschließenden geburt eines gesunden kindes berichtet (bourliere 1992) . eigene daten zur chlormezanon-therapie im 1. trimenon umfassen 6 fälle. von den 5 lebend geborenen kindern wiesen 2 große fehlbildungen auf (arthrogryposis, klumpfuß). die analyse von 36 prospektiv erfassten schwangerschaften mit tetrazepam-exposition im 1. trimenon ergab keinen hinweis auf ein erhöhtes risiko für große fehlbildungen (eigene daten). zu tolperison (z. b. mydocalm ® ) können wir über 22 prospektiv erfasste schwangerschaften berichten. davon wies 1 kind multiple skelettfehlbildungen auf. ausreichende erfahrungen über die anwendung in der schwangerschaft liegen zu keinem dieser teilweise recht alten und therapeutisch überholten mittel vor. empfehlung für die praxis: abgesehen von der notfallbehandlung mit dantrolen bei maligner hyperthermie sind myotonolytika in der schwangerschaft ausnahmesituationen vorbehalten. physiotherapeutische maßnahmen und antiphlogistika/antirheumatika sind vorzuziehen. falls erforderlich, kann kurzzeitig die spannungslösende wirkung des besser untersuchten diazepam genutzt werden. eine exposition mit den genannten myotonolytika rechtfertigt weder einen risikobegründeten schwangerschaftsabbruch noch invasive diagnostik (siehe kapitel 1.15). g 2.1.16 gicht-anfallsbehandlung, colchicin pharmakologie und toxikologie. neben den nichtsteroidalen säureantiphlogistika (nsar) wie ibuprofen ist colchicin das klassische mittel für den akuten gichtanfall. colchicin passiert die plazenta, besitzt als mitosehemmstoff mutagene und genotoxische eigenschaften und wirkt tierexperimentell in verschiedenen spezies embryotoxisch. bei dauertherapie mit täglich 1 mg wurde bei der geburt ein mütterlicher plasmaspiegel von 3,15 ng/ml gemessen, im nabelschnurblut waren es 0,47 ng/ml (amoura 1994) . bei patienten, die mit colchicin behandelt wurden, sind mutagene effekte an den lymphocyten beschrieben worden. colchicin ist die einzige wirksame behandlung zur vorbeugung von attacken beim familiärem mittelmeerfieber (fmf) und der sich bei fmf-patienten chronisch entwickelnden amyloidose der niere. interessant ist, dass das abortrisiko bei unbehandelten frauen mit fmf fast doppelt so hoch ist wie bei patientinnen mit colchicin-therapie (rabinovitch 1992) . teratogene schäden wurden auch nach länger dauernder behandlung des fmf nicht beobachtet (übersicht in . eine kürzlich publizierte große studie einer israelischen arbeitsgruppe, die offenbar früher veröffentlichte arbeiten ( barkei 2000 , rabinovitch 1992 ) einschließt, umfasst 628 schwangerschaften mit colchicin-exposition der mutter und 236, bei denen der vater behandelt wurde. insgesamt wurden 777 lebendgeborene registriert (berkenstadt 2005) . wie bereits in älteren arbeiten diskutiert ( barkei 2000 , rabinovitch 1992 , fand sich bei nicht erhöhter gesamtfehlbildungsrate ein statistisch nicht signifikanter anstieg der häufigkeit chromosomaler anomalien (6 aneuploidien (davon u. a. 2 trisomien 21, 1 klinefelter-syndrom) sowie 1 balancierte y-chromosom-translokation bei mütterlicher erkrankung). einige arbeiten (ben-chetrit 2004 , ben-chetrit 2003 zitieren eine publikation von rabinovitch und mitarbeitern (1992) mit 2.000 geburten nach colchicin-exposition und 4 fällen einer trisomie 21 bei den neugeborenen. dieses zitat war jedoch weder in der originalpublikation nachvollziehbar, noch ließ es sich nach persönlicher kommunikation mit dem autor bestätigen. es führte jedoch zu der anhaltenden diskussion über die notwendigkeit einer amniozentese bei mütterlicher colchicin-therapie. ein leicht erhöhtes risiko für chromosomenaberrationen und aneuploidien wurde zwar immer wieder diskutiert, war aber bisher nicht eindeutig belegbar. aus unserer sicht ist deshalb eine invasive diagnostik, wie z. b. eine amniozentese, primär nicht indiziert. eine neuere arbeit beschäftigt sich explizit mit dem risiko der väterlichen erkrankung an fmf und dem risiko einer therapie des vaters mit colchicin zum zeitpunkt der befruchtung. bei 60 frauen von toxikologie. umfangreiche untersuchungen haben für keines der schon lange gebräuchlichen antihistaminika wie brompheniramin, chlorphenamin, chlorphenoxamin, clemastin, dexchlorpheniramin, dimetinden, diphenhydramin, hydroxyzin, mebhydrolin und pheniramin den früher geäußerten verdacht auf teratogene effekte beim menschen bestätigt (källén 2002 , übersicht in , lione 1996 . bei insgesamt 66 behandlungen mit acrivastin und 35 mit alimemazin in der frühschwangerschaft wurden keine fehlbildungen beobachtet (källén 2002 , wilton 1998 . epidemiologische untersuchungen an insgesamt 187 im 1. trimenon mit astemizol exponierten schwangeren ergaben weder eine erhöhte fehlbildungsrate noch andere abweichungen im schwangerschaftsverlauf , pastuszak 1996 . daten zur einnahme von cetirizin im 1. trimenon finden sich in drei prospektiven studien mit über 300 und einer retrospektiven studie mit 917 schwangerschaften. hinweise für ein erhöhtes fehlbildungsrisiko ergeben sich daraus nicht (weber-schöndorfer 2005 , paulus 2004 , källén 2002 . cyproheptadin (peritol ® ) hat tierexperimentell eine diabetogene wirkung auf die inselzellen des fetalen pankreas. hinweise auf vergleichbare wirkungen beim menschen gibt es bisher nicht. im schwedischen geburtsregister finden sich bei 8 fällen nach behandlung mit cyproheptadin im 1. trimenon keine hinweise auf eine fruchtschädigende wirkung (källén 2002) . bei 39 schwangeren mit ebastin und 16, die fexofenadin im 1. trimenon eingenommen hatten, fanden sich keine fehlbildungen (källén 2002) . 26 eigene fälle mit fexofenadinbehandlung geben ebenfalls keine hinweise auf teratogenität. zur therapie mit hydroxyzin liegen zwei studien mit insgesamt 80 schwangerschaften vor, ohne auffälligkeiten im schwangerschaftsverlauf oder beim neugeborenen . in einem fallbericht zur anxiolytischen therapie mit täglich 150 mg hydroxyzin am ende der schwangerschaft entwickelte das in woche 39 geborene kind 4 stunden nach geburt tonisch-klonische anfälle. die plasmakonzentration 6 stunden nach geburt war identisch mit den mütterlichen werten. die anfälle wurden als entzugssymptomatik gewertet. nach 6 monaten war die neurologische entwicklung des kindes normal (serreau 2005) . nach der anwendung von loratadin in der frühschwangerschaft wurde im schwedischen geburtsregister nach auswertung von 2.780 fällen der verdacht auf ein erhöhtes risiko für das auftreten von hypospadien bei männlichen nachkommen geäußert. das gesamtfehlbildungsrisiko war nicht erhöht (källén 2002 , källén 2001 . dabei handelte es sich meist um leichte formen der hypospadie (grad 1). bei späterer analyse der daten von inzwischen 4.251 loratadinexpositio-nen wurde der ursprüngliche verdacht nicht erhärtet (pers. mitteilung källén 2003) . in anderen studien fanden sich ebenfalls keine hinweise auf einen möglichen zusammenhang zwischen loratadintherapie in der frühschwangerschaft und hypospadien. moretti und mitarbeiter (2003) berichten über 161 schwangerschaften mit loratadinexposition im 1. trimenon und fanden kein erhöhtes fehlbildungsrisiko gegenüber einer kontrollgruppe. in einer weiteren prospektiven studie mit 210 frauen mit loratadintherapie, 163 davon im 1. trimenon, gab es ebenfalls keinen hinweis auf teratogene effekte . hypospadien wurden in beiden studien nicht beobachtet. in einer neuen retrospektiven studie wurden 563 kinder mit hypospadien und 1.441 männliche kontroll-kinder ohne fehlbildungen auf eine mütterliche loratadineinnahme im 1. trimenon verglichen (werler 2004) . ein zusammenhang konnte auch hier nicht nachgewiesen werden. bei weiteren 83 prospektiv erfassten schwangerschaften mit loratadinexposition zwischen schwangerschaftswoche 5 und 15 wurden keine hypospadien gefunden (unveröffentlichte daten des european network of teratology information services -entis 2004) . die analyse eigener daten von 70 schwangerschaften mit loratadintherapie, davon 56 im 1. trimenon behandelt, ergab keine hinweise auf teratogene effekte. keiner der 26 männlichen nachkommen hatte eine hypospadie. im zusammenhang mit meclozintherapie im 1. trimenon bei 16.536 schwangeren des schwedischen geburtsregisters war kein signifikant erhöhtes fehlbildungsrisiko nachweisbar (källén 2003) . es fanden sich jedoch deutlich häufiger mehrlingsschwangerschaften. bei 22 eigenen fällen mit mizolastinexposition gab es keine hinweise auf teratogenität. die analysen von insgesamt 292 schwangeren mit terfenadinbehandlung , loebstein 1999 , schick 1994 ) und weiteren 1164 im 1. trimenon exponierten schwangeren des schwedischen geburtsregisters (källén 2002) ließen kein erhöhtes fehlbildungsrisiko erkennen. in einer untersuchung wurde beobachtet, dass sich nach anwendung von antihistaminika in den letzten beiden schwangerschaftswochen die häufigkeit schwerwiegender augenhintergrundsveränderungen bei frühgeborenen, der so genannten retrolentalen fibroplasie, verdoppelte (zierler 1986) . andere untersucher konnten diesen effekt nicht bestätigen. bei neugeborenen wurden entzugssymptome wie zittrigkeit und diarrhö nach langfristiger antihistaminikabehandlung bis zur geburt (z. b. mit diphenhydramin und hydroxyzin) beschrieben. bei 22 fällen mit lokaler anwendung von levocabastin fanden sich keine fehlbildungen (eigene daten). zu den anderen antihistaminika einschließlich desloratadin (aeri-us ® ) und levocetirizin (xusal ® ) sowie zu den neueren lokaltherapeutika epinastin (relestat ® augentropfen) und olopatadin (opata-nol ® augentropfen) liegen keine erfahrungen in der schwangerschaft vor. empfehlung für die praxis: in der schwangerschaft können h 1 -antihistaminika zur behandlung allergischer erkrankungen eingesetzt werden. ältere präparate mit umfangreicher markterprobung, wie z. b. clemastin und dimetinden, stellen kein problem dar. von den neueren, nicht sedierenden antihistaminika sollten loratadin und cetirizin bevorzugt werden. die einnahme weniger gut dokumentierter medikamente erfordert weder einen risikobegründeten schwangerschaftsabbruch noch invasive diagnostik (siehe kapitel 1.15 pharmakologie und toxikologie. bei der hyposensibilisierung appliziert man einschleichend und kontinuierlich ansteigend dosen des allergens subkutan. das immunsystem bildet daraufhin blockierende antikörper, die das allergen binden sollen, noch bevor es mit sensibilisierten mastzellen reagieren kann. kommt es nach abschluss der behandlung zu einer exposition mit dem allergen, ist die histaminausschüttung der mastzellen deutlich verringert und damit die allergische reaktion schwächer. die hyposensibilisierung hat sich bei heuschnupfen und insektenstichallergien gut bewährt; bei ausgeprägtem asthma ist sie weniger erfolgreich. spezifische embryo-oder fetotoxische effekte sind nicht zu erwarten (metzger 1978) . eine seltene anaphylaktische reaktion kann jedoch den embryo/fetus mittelbar schädigen (luciano 1997) . empfehlung für die praxis: eine vor eintritt der schwangerschaft begonnene hyposensibilisierung kann bei guter verträglichkeit fortgesetzt werden. auf dosissteigerungen sollte wegen möglicher unverträglichkeiten verzichtet werden. eine hyposensibilisierung sollte aus demselben grund nicht während der schwangerschaft begonnen werden, es sei denn, die situation, z. b. bedrohliche reaktionen auf insektenstiche, erfordert diese therapie. ein risikobegründeter schwangerschaftsabbruch ist aufgrund einer hyposensibilisierung ebenso wenig indiziert wie zusätzliche diagnostische maßnahmen (siehe kapitel 1.15 ). zierler s, purohit d. prenatal antihistamine exposure and retrolental fibroplasia. am j epidemiol 1986; 123: 192-6. asthma bronchiale muss auch bei schwangeren ausreichend therapiert werden, um neben dem wohlergehen der mutter eine ausreichende oxygenierung im fetoplazentaren bereich zu gewährleisten. schweres, unzureichend therapiertes asthma ist mit einem höheren risiko für frühgeburtlichkeit, intrauterine wachstumsverzögerung und präeklampsie assoziiert (beckmann 2003 , bracken 2003 , johnson 2002 , olesen 2001 . alle bisher untersuchten antiasthmatika haben sich als verträglich für den embryo bzw. fetus erwiesen (schatz 2004) . dieser abschnitt orientiert sich an der aktuellen, vom schweregrad abhängigen stufentherapie des asthmas, geht aber auch auf nicht mehr aktuelle arzneimittel ein. am ende des abschnitts werden expektoranzien und antitussiva besprochen. schweregrad 1: leichte intermittierende symptomatik, wenn symptome seltener als ein-oder zweimal pro woche auftreten, wird ein inhalierbares, kurzwirksames g 2 -sympathomimetikum bei bedarf eingenommen. schweregrad 2: persistierendes leichtes asthma, definiert durch gelegentliche nächtliche symptome oder symptome tagsüber, die aber noch nicht täglich auftreten, wird mit einer basistherapie behandelt. dies sind in der regel ein inhalatives corticoid oder bei allergischem asthma cromoglicinsäure. bedarfsweise kann zusätzlich ein inhalierbares, kurzwirksames g 2 -sympathomimetikum genommen werden. schweregrad 3: persistierendes mittelgradiges asthma mit täglichen beschwerden und nächtlichen symptomen einmal pro woche und häufiger sollte mit einem langwirksamen g 2 -sympathomimetikum zusätzlich zum inhalativen corticoid (ggf. dosissteigerung gegenüber schweregrad 2!) therapiert werden. bedarfsweise kann wieder ein kurzwirksames g 2 -sympathomimetikum eingenommen werden. sollte das nicht ausreichen, kommen auch theophyllin und/oder anticholinergika in frage, außerhalb der schwangerschaft auch leukotrien-rezeptor-antagonisten. schweregrad 4: persistierendes schweres asthma mit ständigen symptomen wird oral mit glucocorticoiden (z. b. prednisolon) therapiert oder mit einer kombination aus drei oder mehr substanzen aus stufe 3; selten sind orale glucocorticoide in kombination mit mehreren anderen substanzen erforderlich. g 2.3.1 selektiv wirkende g 2 -sympathomimetika pharmakologie. beim vegetativen nervensystem unterscheidet man im bereich des sympathikus § -und g -rezeptoren, letztere werden in g 1und g 2 -rezeptoren unterteilt. stimulierung der g 1 -rezeptoren bewirkt am herzen eine aktivitätssteigerung. g 2 -rezeptoren vermitteln hingegen ein erschlaffen der glatten muskulatur an den gefäßen (vasodilatation), an den bronchien (bronchodilatation) und am uterus (tokolyse) und führen zum anstieg der konzentration von glucose, fettsäuren und ketonkörpern im blut. darüber hinaus fördern g 2 -agonisten an den bronchien die mukoziliäre clearance und reduzieren die gefäßpermeabilität. ein sympathomimetikum, das ausschließlich g 2 -sympathomimetisch wirkt, ohne gleichzeitig andere adrenerge rezeptoren zu aktivieren, gibt es bisher nicht. sympathomimetika mit vorwiegender g 2 -wirksamkeit haben in der asthmatherapie aber inzwischen solche mittel ersetzt, die noch deutliche g 1 -aktivität aufwiesen. g 2 -sympathomimetika wirken nach inhalation ebenso schnell wie nach intravenöser injektion und erreichen ihr wirkungsmaximum nach 10-20 minuten. durch die depotfunktion der bronchialschleimhaut verlängert sich zudem der therapeutische effekt gegenüber einer parenteralen anwendung, obwohl die plasmakonzentration nur bei 20 % liegt. entsprechend geringer fallen die unerwünschten wirkungen im vergleich zur systemischen applikation aus. nach oraler gabe von g 2 -sympathomimetika werden 30-55 % resorbiert. unabhängig von der applikationsart werden diese mittel nach metabolisierung in der leber und kopplung an sulfat mit dem urin ausgeschieden. fenoterol (z. b. berotec ® ) , reproterol (in bronchospasmin ® ), salbutamol (z. b. sultanol ® ) und terbutalin (z. b. bricanyl ® ) sind pharmaka, die ein günstiges verhältnis zwischen g 2 -und g 1 -stimulierung aufweisen und daher seit vielen jahren mit erfolg zur behebung der bronchokonstriktion bei asthma eingesetzt werden. sie gehören zu den kurzwirksamen vertretern dieser arzneimittelgruppe. ihre wirkung ist auf 4-6 stunden begrenzt. einige untersuchungen legen nahe, dass die anwendung von fenoterol mit einem erhöhten risiko für bedrohliche kardiopulmonale nebenwirkungen verbunden ist. demgegenüber sind formoterol (z. b. oxis ® ) und salmeterol (z. b. serevent ® ) länger als 12 stunden wirksam. sie sind nicht zur behandlung akuter asthmasymptome geeignet und stellen keinen ersatz für eine basistherapie dar, vielmehr sollten sie nur kombiniert mit z. b. inhalierbaren glucocorticoiden gegeben werden (bekanntmachung des bundesinstituts für arzneimittel und medizinprodukte 9/2003). einer noch unveröffentlichten studie des herstellers glaxosmithkline zufolge kann die langfristige einnahme von salmeterol zu einem gerin-gen, aber signifikanten anstieg der durch asthma bedingten todesfälle führen (arzneimittelbrief 2005) . sympathomimetika hemmen im 2. und 3. trimenon die kontraktilität der uterusmuskulatur. sie werden daher auch als tokolytika eingesetzt. toxikologie. es gibt keine hinweise darauf, dass g 2 -sympathomimetika fehlbildungen hervorrufen oder das fetale wachstum beeinträchtigen (z. b. bakhireva 2004) . alle sympathomimetika können jedoch in entsprechend hoher dosis nicht nur bei der mutter, sondern auch beim fetus eine tachykardie oder andere rhythmusstörungen verursachen. eine kasuistik beschreibt eine fetale tachykardie mit vorhofflattern in woche 33, nachdem die mutter versehentlich über 24 stunden inhalativ überdosen von albuterol erhalten hatte und selbst eine herzfrequenz von 90-100/min aufwies. die symptomatik sistierte spontan nach absetzen der medikation (baker 1997) . g 2 -sympathomimetika können die kohlenhydrattoleranz beeinträchtigen. das ist bei einer diabetogenen stoffwechsellage der schwangeren zu berücksichtigen (källén 2000) . für clenbuterol (z. b. spiropent ® ), pirbuterol und tulobuterol (z. b. brelomax ® ), bambuterol (bambec ® ) liegen keine für eine spezifische risikobewertung ausreichenden erfahrungen zur anwendung im 1. trimenon vor. es gibt jedoch auch bei diesen wirkstoffen bislang keine hinweise auf teratogene effekte beim menschen. empfehlung für die praxis: sympathomimetika gehören auch in der schwangerschaft zur asthmatherapie, sie dürfen gemäß den empfehlungen des asthmastufenplans angewendet werden. salbutamol ist mittel der 1. wahl unter den kurz wirksamen sympathomimetika. am ende der schwangerschaft müssen wehenhemmung und g 2 -spezifische effekte beim fetus bedacht werden (siehe oben). inhalierbare corticosteroide sind mittel der wahl in der asthmabasis-therapie der schweregrade 2 bis 4. sie wirken antiinflammatorisch, d. h. antiphlogistisch, antiallergisch und immunsuppressiv. außerdem haben sie einen günstigen effekt auf die ansprechbarkeit der betarezeptoren an den bronchien. in der asthma-therapie werden als inhalierbare glucocorticoide budesonid (pulmicort ® ) und folgende halogenierte derivate bevorzugt verwendet: beclometason (z. b. beconase ® , sanasthmyl ® ), flunisolid (syntaris ® ), fluticason (z. b. atemur ® ) und mometason (z. b. asmanex ® ). seit 2005 ist der wirkstoff ciclesonid (alvesco ® ) in deutschland als inhalatives corticoid zur asthma-therapie bei erwachsenen zugelassen. theoretische bedenken gegen die anwendung von inhalierbaren glucocorticoiden in der schwangerschaft beruhten auf ergebnissen einiger studien bei systemischer anwendung, in denen eine erhöhte rate an lippen-gaumen-spalten bei den kindern diskutiert wird, sowie auf der beobachtung, dass eine dauerhafte cortisontherapie in der schwangerschaft bei entsprechender dosierung zur fetalen wachstumsverzögerung führen kann. studien zur anwendung von inhalierbaren corticosteroiden in der schwangerschaft konnten diese zweifel beseitigen (martel 2005 , bakhireva 2004 , schatz 2004 . budesonid ist mit mehr als 6000 schwangeren (gluck 2005) das am besten untersuchte mittel, gefolgt von beclometason (ca. 500 schwangere) und fluticason (ca. 130). auch bei triamcinolon (ca. 100) und flunisolid (ca. 25) gibt es bisher keinen hinweis auf ein erhöhtes fehlbildungsrisiko oder auf unerwünschte fetale effekte (namazy 2004 , norjavaara 2003 , källén 1999 . das gilt auch für das am schlechtesten untersuchte mometason (eigene beobachtungen). bei schwerem asthma oder zur therapie des asthmaanfalls dürfen glucocorticoide auch systemisch appliziert werden. empfehlung für die praxis: inhalierbare glucocorticoide sind gemäß asthmastufenplan auch in der schwangerschaft mittel der wahl, wobei besser untersuchte substanzen zu bevorzugen sind. bei systemischer anwendung von glucocorticoiden (siehe kapitel 2.15.9) ist die dosis, sofern es klinisch möglich ist, rasch zu reduzieren, um unerwünschte wirkungen (auch auf die mutter) zu verhindern. wird bis zur geburt systemisch behandelt, müssen geburtshelfer und pädiater über die medikation informiert werden, um mögliche stoffwechselauswirkungen beim neugeborenen zu beachten. es gibt keine wissenschaftlich belegte corticosteroiddosis, die einen risikobegründeten schwangerschaftsabbruch erforderlich macht (siehe kapitel 1.15 zur prävention des allergischen asthmas und des belastungsasthmas wird cromoglicinsäure als pulver oder lösung vorbeugend inhaliert. nur 1-2 mg einer 20-mg-dosis erreichen die alveolen, der rest wird verschluckt. ein prozent hiervon wird im darm resorbiert und unverändert mit dem urin ausgeschieden. die halbwertszeit beträgt 60-90 minuten. die wirkung tritt erst nach 3-5 tagen ein. cromoglicinsäure wirkt nicht embryotoxisch, wie sich bei einer großen zahl behandelter schwangerer bestätigt hat (überblick bei . nedocromil (z. b . tilade ® ), dessen wirkungsmechanismus dem von cromoglicinsäure ähnelt, ist in der schwangerschaft noch nicht ausreichend untersucht. hinweise auf unverträglichkeiten beim ungeborenen liegen nicht vor. empfehlung für die praxis: cromoglicinsäure kann zur prävention eines allergisch bedingten asthmas auch schwangeren gegeben werden. es darf auch als augen-und nasentropfen verwendet werden. eine anwendung von nedocromil erfordert keine konsequenzen. pharmakologie und toxikologie. substanzen wie ketotifen (z. b. zaditen ® ) und oxatomid sind bezüglich ihrer pränatalen verträglichkeit bisher nicht ausreichend untersucht. hinweise auf embryotoxische wirkungen beim menschen liegen nicht vor. empfehlung für die praxis: ketotifen und oxatomid gehören nicht zum standardtherapieschema bei asthma und sollten in der schwangerschaft nicht angewendet werden. eine dennoch erfolgte applikation stellt weder eine indikation zum risikobegründeten abbruch der schwangerschaft noch für zusätzliche diagnostik dar (siehe kapitel 1.15 ). die daraus resultierende erhöhung der intrazellulären camp-konzentration bewirkt eine erschlaffung der bronchialmuskulatur. die plasmakonzentration des theophyllins korreliert gut mit der bronchodilatation, aber auch mit den unerwünschten wirkungen. bei mäßiggradiger obstruktion wirkt theophyllin weniger bronchodilatatorisch als g 2 -sympathomimetika. theophyllin wirkt am herzen gering positiv inotrop und stimuliert verschiedene abschnitte des zentralnervensystems. es steigert die empfindlichkeit des atemzentrums gegenüber co 2 und verursacht auf diese weise eine zunahme der atemfrequenz und -tiefe. diesen effekt nutzt man zur behandlung der apnoeneigung bei frühgeborenen. wie andere methylxanthine wird theophyllin nach oraler gabe rasch resorbiert und in der leber demethyliert und oxidiert. nur etwa 10 % werden unverändert über die nieren ausgeschieden. theophyllin ist plazentagängig (arwood 1979) . seine halbwertszeit beträgt etwa 5 stunden. bei schwangeren ist sie mit etwa 8 stunden verlängert (sutton 1978) . aufgrund der veränderten proteinbindung sind bei schwangeren in der regel serumspiegel von 8-12 ? g/ml therapeutisch ausreichend und führen außerdem zu einer geringeren nebenwirkungsrate bei den neugeborenen (schatz 1993) . kinder metabolisieren theophyllin rascher als erwachsene, bei frühgeborenen sind jedoch halbwertszeiten bis zu 30 stunden gemessen worden (aranda 1976). toxikologie. obwohl theophyllin im tierversuch in hohen konzentrationen teratogen wirkt, wurden beim menschen keine embryotoxischen effekte beobachtet (überblick bei . während der spätschwangerschaft wurde unter theophyllin eine zunahme der fetalen atembewegungen (ohne pathologische relevanz) beobachtet (ishikawa 1996) . früher behauptete zusammenhänge zwischen mütterlicher therapie und erhöhtem risiko für eine nekrotisierende enterokolitis (nec) beim neugeborenen wurden unter anderem in einer studie an 59 schwangeren widerlegt, die theophyllin als tokolytikum oder zur surfactantbildung vor woche 34 erhalten hatten (zanardo 1996) . nach zwei neueren arbeiten (dombrowski 2004 , schatz 2004 ) gab es keine nennenswerten unterschiede hinsichtlich der geburtsparameter bei inhalierbaren g 2 -sympathomimetika, inhalativen corticoiden und theophyllin. nur bei den schwangeren selbst war die nebenwirkungsrate unter theophyllin höher. beschrieben sind vor allem zittrigkeit, tachykardie und erbrechen. empfehlung für die praxis: theophyllin kann in der gesamten schwangerschaft bei asthma gemäß stufenplan angewendet werden. die niedrigste therapeutisch sinnvolle serumkonzentration sollte angestrebt werden, um nebenwirkungen bei mutter und neugeborenem zu minimieren. g 2.3.5 anticholinergika ipratropiumbromid und oxitropiumbromid pharmakologie und toxikologie. da eine bronchokonstriktion auch über den nervus vagus induzierbar ist, können anticholinerg wirkende substanzen therapeutisch wirksam sein. ipratropiumbromid (z. b. atrovent ® ) ist in der lage, eine vollständige pulmonale vagolyse zu bewirken. seine bronchodilatatorische aktivität kann zwei drittel der aktivität von g 2 -sympathomimetika erreichen. es wird allein (z. b. atrovent ® ) oder in kombination mit fenoterol (berodual ® ) angeboten. hinweise auf pränatale toxizität liegen nicht vor. oxitropiumbromid und tiotropiumbromid (spiriva ® ) sind bezüglich einer anwendung in der schwangerschaft unzureichend untersucht. empfehlung für die praxis: ipratropiumbromid darf in der schwangerschaft zur bronchodilatation verwendet werden. die anwendung von oxitropiumbromid rechtfertigt weder einen risikobegründeten schwangerschaftsabbruch noch zusätzliche diagnostik (siehe kapitel 1.15). g 2.3.6 antileukotriene pharmakologie und toxikologie. die leukotrien-rezeptor-antagonisten montelukast (singulair ® ), zafirlukast und pranlukast sowie der lipoxygenase-inhibitor zileuton werden zur vorbeugung asthmatischer beschwerden eingesetzt. der hersteller merck berichtet über 137 abgeschlossene prospektiv erfasste schwangerschaften unter montelukast. von den lebendgeborenen waren 116 im 1. trimenon exponiert, es fanden sich 4 kinder mit anomalien, darunter ein mädchen mit fehlender linker hand. diese als "amnionband-syndrom" klassifizierte anomalie wurde nicht dem medikament zugeschrieben. eine weitere extremitätenanomalie (hypoplasie des rechten daumens) wurde bei 33 prospektiv dokumentierten schwangerschaften des schwedischen medizinischen geburtsregisters beobachtet. unter den 8 retrospektiven fallberichten des herstellers befand sich ein neugeborenes mit fehlender anlage von unterarm und hand. unsere eigenen daten umfassen 20 prospektiv erfasste schwangerschaften mit exposition im 1. trimenon ohne hinweise auf extremitätenfehlbildungen. auch die ergebnisse von 96 in nordamerikanischen teratologischen zentren beobachtete schwangerschaften (montelukast = 73, zafirlukast = 23; bakhireva 2006) sprechen nicht für ein substantiell erhöhtes gesamtfehlbildungsrisiko, reichen aber nicht für eine differenzierte risikoeinschätzung. weder können daraus teratogene eigenschaften noch eine unbedenklichkeit für die anwendung schwangerer gefolgert werden. pharmakologie und toxikologie. iodsalze, z. b. iodkalium (kalium iodatum) können in der schwangerschaft in sekretolytischer dosis beim fetus und neugeborenen die schilddrüsenfunktion beeinträchtigen (therapeutische einzeldosis beim erwachsenen 250-500 mg). dies ist nicht zu verwechseln mit der für schwangere empfohlenen iodsubstitution (200 ? g/tag). eine versehentliche gabe von kalium iodatum zur sekretolyse in der schwangerschaft führt bei kurzfristiger anwendung nicht zur strumaentwicklung . die reifung des zentralnervensystems, die von einer ausreichenden versorgung mit schilddrüsenhormons abhängig ist, kann jedoch gestört werden, wenn ab ende des 1. trimenon eine hohe ioddosis die dann bereits aktive schilddrüse des fetus supprimiert. empfehlung für die praxis: die gabe von iodsalzen als expektorans ist in der schwangerschaft kontraindiziert. eine versehentliche sekretolyse mit iod erfordert aber weder einen risikobegründeten schwangerschaftsabbruch noch zusätzliche vorgeburtliche diagnostik (siehe kapitel 1.15 ). dextromethorphan (z. b . neotussan ® ) hat keine analgetische komponente und ein offenbar geringeres (aber dennoch vorhandenes!) suchtpotenzial. der antitussive effekt ist vergleichbar mit dem von codein (reynolds 1989) . ausgehend von tierexperimentellen befunden wurde dextromethorphan ende der 90er jahre ein teratogenes potenzial unterstellt. aufgrund der erfahrungen an über 500 schwangerschaften hat sich dieser verdacht für den menschen nicht bestätigt (martinez-frias 2001 , einarson 1999 , andaloro 1998 . andere antitussiva wie benproperin (tussafug ® ), clobutinol (z. b. silomat ® ), dropropizin (larylin ® ), eprazinon (eftapan ® ), isoaminil, noscapin (z. b. capval ® ) , pentoxyverin (sedotussin ® ) und pipazetat sind hinsichtlich pränataler risiken beim menschen unzureichend untersucht. empfehlung für die praxis: in begründeten fällen darf codein bei hartnäckigem, trockenem husten oder in kombination mit paracetamol als analgetikum in allen phasen der schwangerschaft verordnet werden. auch dextromethorphan kann als antitussivum eingesetzt werden. falls codein präpartal oder regelmäßig in hoher dosis als suchtmittel oder zur substitutionsbehandlung heroinabhängiger genommen wird, muss beim neugeborenen mit atemdepression und im fall hoher dosen auch mit bedrohlichen entzugserscheinungen gerechnet werden. wurden die nicht empfohlenen mittel verwendet, erfordert dies weder einen risikobegründeten schwangerschaftsabbruch noch invasive diagnostik (siehe kapitel 1.15). g 2.3.10 unspezifisch wirkende sympathomimetika die im folgenden besprochenen arzneimittel gehören nicht zum aktuellen asthma-therapiestufenplan. einige der sympathomimetika finden sich in kombination mit anderen wirkstoffen in rezeptfreien mitteln gegen erkältungen, deren anwendung nicht erwünscht ist. pharmakologie und toxikologie. orciprenalin (alupent ® ) wirkt stimulierend auf g -rezeptoren, allerdings nicht so selektiv wie die g 2 -sympathomimetika. entsprechend stärker fallen die unerwünschten wirkungen am herzen und im stoffwechsel aus. das gilt auch für die stimulierende wirkung auf das zentralnervensystem und die verminderung von tonus und motilität im magen-darm-trakt. hinweise auf spezifische embryo-oder fetotoxische wirkungen liegen weder zu orciprenalin noch zu hexoprenalin vor. empfehlung für die praxis: orciprenalin und hexoprenalin gehören nicht zur standardtherapie des asthmas. spezifische g 2 -sympathomimetika sind vorzuziehen. eine dennoch erfolgte therapie rechtfertigt weder einen risikobegründeten schwangerschaftsabbruch noch zusätzliche diagnostik (siehe kapitel 1.15 ). pharmakologie und toxikologie. adrenalin (epinephrin; z. b. suprarenin ® ) ist ein katecholamin, das natürlicherweise im körper vorkommt und sowohl § -als auch g -adrenerge wirkung besitzt. bei asthma bronchiale trägt zwar die schwache stimulierung der § -rezeptoren über eine vasokonstriktion zur verminderung des ödems der bronchialschleimhaut bei, allerdings sind die § -sympathomimetischen herz-kreislauf-wirkungen (tachykardie, extrasystolen, hypertonie) so stark, dass selektive g 2 -sympathomimetika vorgezogen werden. adrenalin ist notfallsituationen vorbehalten und wird dann i.v. oder endotracheal appliziert bzw. inhalativ als aerosol gegeben (z. b. zum abschwellen der oberen atemwege). nach oraler gabe ist es unwirksam, weil es im magen-darm-trakt inaktiviert wird. katecholamine sind plazentagängig, sie werden dort aber teilweise enzymatisch inaktiviert (morgan 1972) . im gegensatz zu tierexperimentellen ergebnissen haben sich beim menschen keine hinweise auf teratogene effekte ergeben . eine systemische anwendung kann die durchblutung von uterus und plazenta beeinträchtigen und zur fetalen hypoxie führen. empfehlung für die praxis: adrenalin ist vitalen indikationen vorbehalten. es gehört nicht zur asthma-standardtherapie. eine exposition rechtfertigt weder einen risikobegründeten schwangerschaftsabbruch noch invasive diagnostik (siehe kapitel 1.15 ). die einigen lokalanästhetika beigefügten mengen sind als unbedenklich anzusehen. pharmakologie und toxikologie. isoprenalin weist keine § -sympathomimetische wirkung, aber eine etwa gleich starke g 1 -und g 2 -aktivität auf. die g 1 -wirkung am herzen schränkt die verwendung auf notfallsituationen ein, z. b. zur abschwellung der oberen atemwege. spezifische embryo-oder fetotoxische wirkungen wurden bisher nicht bekannt. die systemische gabe von isoprenalin könnte, ähnlich wie bei adrenalin, eine verminderte utero-plazentare durchblutung mit fetaler hypoxie verursachen. bei kurzfristiger inhalativer anwendung oder in dermatologischen präparaten ist dies aber nicht zu erwarten. pharmakologie und toxikologie. ephedrin ist das älteste bronchodilatatorisch wirkende asthmamittel. es gehört zu den indirekten sympathomimetika, die über eine vermehrte ausschüttung der körpereigenen katecholamine wirken. ephedrin hat sowohl § -als auch g -aktivität mit entsprechenden unerwünschten wirkungen, so dass es inzwischen als ungeeignet für die asthmatherapie erachtet wird. heute findet man ephedrin und andere (indirekte) sympathomimetika wie pseudoephedrin, phenylephrin, phenylpropanolamin in kombinationsmitteln gegen erkältungen. eine unveröffentlichte studie aus schweden untersuchte erkältungspräparate auf mögliche teratogene effekte: im 1. trimenon nahmen mehr als 2.000 schwangere phenylpropanolamin ein, ca. 140 phenylpropanolamin plus cinnarizin und mehr als 20 pseudoephedrin. die fehlbildunsgrate war in keiner der gruppen erhöht (källén 2005, persönliche kommunikation) . auch in der bundesrepublik deutschland werden produkte, die zusätzlich dextromethorphan, doxylamin etc. enthalten, noch angeboten (z. b. wick medinait ® ). zumindest bei unkontrolliertem gebrauch und höheren dosen dieser mittel sind embryotoxische wirkungen durch sympathomimetika nicht auszuschließen, wie publizierte fallberichte über extremitätendefekte in erinnerung rufen (gilbertbarness 2000) . empfehlung für die praxis: ephedrin gehört nicht zur asthma-standardtherapie. mittel gegen erkältungen, die ephedrin und andere sympathomimetika enthalten, sollen nicht genommen werden. eine (versehentliche) exposition rechtfertigt jedoch weder einen risikobegründeten schwangerschaftsabbruch noch invasive diagnostik (siehe kapitel 1.15 morgendliche übelkeit und erbrechen gehören zu den unangenehmen begleiterscheinungen vieler schwangerschaften. man schätzt, dass 50-70 % aller schwangeren in den ersten wochen unter morgendlicher übelkeit leiden und die hälfte von ihnen zusätzlich unter erbrechen (emesis gravidarum). nur in sehr seltenen fällen (0,3-2 %) ist das erbrechen so stark, dass ein klinikaufenthalt wegen störungen des energie-und elektrolythaushaltes erforderlich ist (hyperemesis gravidarum). während früher darüber diskutiert wurde, ob übelkeit und erbrechen prognostisch ungünstige faktoren für die schwangerschaft darstellen, gibt es heute eine debatte darüber, ob das fehlen von morgendlicher übelkeit ein prognostisch ungünstiges zeichen für die entwicklung des kindes ist. ging in einer kontrollierten prospektiven studie dieser frage nach und verglich kinder von schwangeren ohne übelkeit und erbrechen mit solchen, die daran litten und eine standarddosis doxylamin-pyridoxin (kontrollgruppe 1) bzw. eine höhere dosis doxylamin-pyridoxin (kontrollgruppe 2) erhielten. es gab keine unterschiede zwischen den kindern der verschiedenen gruppen. bei jüngeren schwangeren und denen, die schon mindestens ein kind haben, sowie jenen, die während der schwangerschaft zu hause bleiben, ermittelte källén (2003) ein höheres risiko für übelkeit und erbrechen. über den wert von antiemetika wurde intensiv diskutiert, weil dieser arzneimittelgruppe ursprünglich ein embryotoxisches potenzial unterstellt wurde und gleichzeitig die wirksamkeit der therapie umstritten war. umfangreiche untersuchungen ergaben keinen anhalt für ein erhöhtes fehlbildungsrisiko der klassischen antiemetika (asker 2005, mazotta 2000 , seto 1997 , brent 1995 . auch der von einer untersuchergruppe beschriebene zusammenhang von retrolentaler fibroplasie bei frühgeborenen und antihistaminika-anwendung in den letzten beiden schwangerschaftswochen (zierler 1986) mazotta 2000 , seto 1997 , lione 1996 . untersuchungsergebnisse berichten über eine besserung der symptomatik bei 45 % der behandelten, diese war bei 25 % komplett (übersicht in broussard 1998) . dimenhydrinat soll ebenso wie diphenhydramin einen wehen fördernden effekt besitzen (broussard 1998) . hinweise auf ein teratogenes risiko beim menschen liegen nicht vor, dies wurde kürzlich in einer retrospektiven fall-kontroll-studie bestätigt (czeizel 2005) . empfehlung für die praxis: dimenhydrinat ist akzeptabel, wenn kein risiko für eine frühgeburt vorliegt. meclozin ist jedoch antiemetikum der wahl in der schwangerschaft. ten. daher wird es heute als beruhigungsmittel und bei schlafstörungen verwendet. in den 70er jahren wurde neben anderen antihistaminika auch diphenhydramin ein teratogenes potenzial unterstellt. dies ließ sich in späteren untersuchungen nicht bestätigen (mazotta 2000 , seto 1997 , lione 1996 . bei ca. 150 im 1. trimenon behandelten schwangeren wurde eine fehlbildungsrate von 1,1 % gefunden (asker 2005) . diphenhydramin hat, ebenso wie dimenhydrinat, einen oxytocinartigen, wehenfördernden effekt, der in den 50er und 60er jahren unter der geburt genutzt wurde (broussard 1998 , brost 1996 , smithells 1978 , der sich in ausführlichen prospektiven und retrospektiven studien jedoch nicht bestätigen ließ (zusammenfassung in brent 1995 , mckeigue 1994 . aufgrund der kritik von verbraucherverbänden im in-und ausland wurde lenotan ® 1984 auch in der bundesrepublik deutschland vom markt genommen. vor einigen jahren wurde dann das risiko nochmals bewertet, dabei gab es definitiv keinen anhalt für einen teratogenen effekt (brent 2003 , kutcher 2003 . auch eine therapie mit höherer dosierung hat nach einer vergleichenden studie keine negativen auswirkungen auf die schwangerschaft (atanackovic 2001 (källén 2003 , seto 1997 , lione 1996 (bsat 2003 , einarson 1998 (mazotta 2000 , broussard 1998 . dies bestätigt eine neuere schwedische studie, die unter ande-phenothiazin-antiemetika rem 4.740 im 1. trimenon mit promethazin behandelte schwangere untersuchte (asker 2005) . auch triflupromazin (das frühere psyquil ® ) scheint nicht embryotoxisch zu wirken (mcelhatton 1992) . thiethylperazin wird vor allem in der schweiz und in osteuropa als antiemetikum genutzt, ohne dass sich bisher hinweise auf risiken für den fetus ergaben (einarson 1998) . livan 1996) . fallberichte beschreiben die erfolgreiche intravenöse anwendung nach versagen anderer arzneimittel bei schwerer hyperemesis gravidarum zwischen den schwangerschaftswochen 6 und 30. die neugeborenen waren unauffällig (siu 2002 , world 1993 , guikontes 1992 . in einer prospektiven studie wurden 176 mit ondansetron behandelte schwangere mit zwei unterschiedlichen kontrollgruppen verglichen (vutyavanich 1995) . eine weitere untersuchung ergab nur eine wirksamkeit bei starker übelkeit, bei leichter und mittlerer symptomatik war pyridoxin placebo nicht überlegen (sahakian 1991) . scopolamin (scopoderm ® tts) ist ein parasympatholytikum, das äußerlich als pflaster zur antiemetischen behandlung eingesetzt wird. bei 309 im 1. trimenon behandelten schwangeren wurde keine erhöhte fehlbildungsrate festgestellt alginsäure oder alginat führen in anwesenheit von magensäure zu einem viskösen gel, das auf dem mageninhalt "schwimmt", wie eine mechanische barriere wirkt und damit den gastroösophagealen reflux reduziert. vor kurzem wurde eine studie an 150 schwangeren veröffentlicht, die die wirksamkeit und sicherheit im 2./3. trimenon untersucht hat . calciumcarbonat neutralisiert die salzsäure unter bildung von calciumchlorid, kohlendioxid und wasser. etwa 15-30 % der oral aufgenommenen dosis werden resorbiert. bei patienten mit normaler nierenfunktion besteht nach einnahme von calciumcarbonathaltigen präparaten in therapeutischer dosierung keine gefahr einer hypercalcämie. exzessive calciumzufuhr kann jedoch bei schwangeren zu dem äußerst seltenen milch-alkali-syndrom führen (gordon 2005) , so dass nicht mehr als 1,5 g elementares calcium (entsprechend 3,75 g calciumcarbonat) täglich eingenommen werden sollten. bei einer schwangeren, die einen monat lang täglich 10 rennie und ca. 600 ml milch zu sich nahm, litt das neugeborene an einer vorübergehenden hypercalcämie. eine andere kasuistik beschreibt krämpfe als folge einer hypocalcämie beim neugeborenen, dessen mutter exzessiv während der gesamten schwangerschaft antacida eingenommen hatte (robertson 2002) . im gegensatz zu der o.g. fallbeschreibung von gordon (2005) (ruigomez 1999 , källén 1998 . anzahl und muster der fehlbildungen waren gegenüber der jeweiligen kontrollgruppe nicht auffällig. auch frühgeburten und intrauterine wachstumsretardierung traten nicht häufiger auf. zu vergleichbaren ergebnissen kommt eine neuere multizentrische prospektive studie des european network of teratology information services (entis) mit 553 schwangeren, davon wurden 501 im 1. trimenon behandelt. bei ranitidin (n=335), cimetidin (n=113), famotidin (n=75), nizatidin (n=15) und roxatidin (n=15) zeigte sich keine erhöhte fehlbildungsrate. allerdings war die frühgeburtenrate in der behandelten gruppe höher, ohne dass sich dafür eine erklärung fand. die 2 bei famotidin beobachteten neuralrohrdefekte sind eher als zufällig zu betrachten in einem kanadischen bericht zu 10 anwendungen von pinaverium in der schwangerschaft werden 9 unauffällige kinder und ein spontanabort genannt. fünf mütter hatten das mittel im 1. trimenon, fünf zwischen schwangerschaftswoche 12 und 16 eingenommen. in all diesen fällen war die einnahme unbeabsichtigt, es war mit dem antiemetikum diclectin verwechselt worden (einarson 1999) . darifenacin (emselex ® ) ist ein selektiver m 3 -rezeptorantagonist, der zur behandlung der überaktiven harnblase eingesetzt wird. erfahrungen in der schwangerschaft gibt es noch nicht. spezifische embryotoxische effekte beim menschen sind bei anwendung der genannten belladonna-alkaloide bisher nicht beobachtet worden. auch die anwendung unter der geburt wird, soweit dokumentiert (z. b. für das anticholinergikum glycopyrronium) offenbar gut vom fetus vertragen (ure 1999 mesalazin wird sehr häufig in der schwangerschaft verordnet, ohne dass sich bisher hinweise auf teratogene wirkungen ergeben haben (habel 1993 , diav-citrin 1998 , marteau 1998 ursodeoxycholsäure wirkt bei hepatozellulären schäden, die durch gallensäuren induziert sind, also vor allem bei cholestatischen erkrankungen, wie der primär biliären zirrhose. aufgrund der symptomatischen wirkung ist eine dauerbehandlung erforderlich. aussagefähige untersuchungen zur anwendung bei schwangeren gibt es bisher nur für ursodeoxycholsäure in der zweiten schwangerschaftshälfte, vor allem zur gut wirksamen behandlung bei schwangerschaftscholestase (roncaglia 2004 , mazella 2001 , die mit juckreiz, ikterus sowie erhöhter alkalischer phosphatase (ap) und + -glutamyltranspeptidase ( + -gt) einhergeht. unter dieser therapie wurde nicht nur eine besserung mütterlicher symptome und laborparameter beob-achtet, sondern auch eine verringerung der erkrankungsbedingten frühgeburtlichkeit (palma 1997) . es wurde keine zunahme toxischer ursodeoxycholsäuremetaboliten im mekonium gefunden. der gallensäuregehalt des mekoniums kann sich durch die mütterliche erkrankung verändern, nicht aber durch die medikation (rodrigues 1999 (robert 1992) . eine studie des european network of teratology information services (entis) mit 168 vornehmlich dexfenfluramin exponierten schwangerschaften erbrachte keine hinweise auf teratogene eigenschaften der appetitzügler (vial 1992) . publizierte erfahrungen zu sibutramin, das strukurell amphetamin ähnelt und ein wiederaufnahmehemmstoff von serotonin, noradrenalin und (in geringerem maß) dopamin ist, liegen nur in form von 10 bzw. 2 fallberichten vor , kardioglu 2004 , aus denen sich kein spezifisches risiko ergibt. wir überblicken zurzeit 26 im 1. trimenon exponierte schwangere: von 19 lebend geborenen kindern hatten zwei fehlbildungen, eines eine einseitige nierenagenesie, das andere einen vorhofseptumdefekt. orlistat wird aus dem gastrointestinaltrakt kaum resorbiert, so dass teratogene effekte unwahrscheinlich erscheinen. zahlreiche publikationen beschäftigen sich mit dem risiko für schwangerschaftskomplikationen einschließlich fehlbildungen durch mütterliche adipositas (scialli 2006 penicilline gehen ungehindert auf den fetus über und lassen sich in der amnionflüssigkeit nachweisen. es gibt bei mehreren tausend ausgewerteten schwangerschaften keine anzeichen dafür, dass die therapie mit penicillinen embryo-oder fetotoxisch wirkt (berkovitch 2004 , dencker 2002 a, larsen 2000 da die clearance von cephalosporinen in der schwangerschaft erhöht ist, müssen ggf. korrekturen von dosis oder dosisintervall vorgenommen werden (heikkilä 1994) . cephalosporine sind plazentagängig und in der amnionflüssigkeit in bakteriziden konzentrationen nachweisbar. im zusammenhang mit cephalosporinen der zweiten und dritten generation, insbesondere cefotetan, wurden immunhämolytische ereignisse bei den behandelten patientinnen beobachtet (garratty 1999) . nach bisherigen beobachtungen, z. b. zu cefuroxim im 1. trimenon (berkovitch 2000) , verursachen cephalosporine in therapeutischer dosis keine teratogenen schäden (czeizel 2001 b da die clearance von lactam-antibiotika und g -lactamase-inhibitoren in der schwangerschaft erhöht ist, müssen ggf. korrekturen von dosis oder dosisintervall vorgenommen werden (heikkilä 1994) . soweit untersucht, passieren g -lactam-antibiotika oder g -lactamase-inhibitoren die plazenta und erreichen den fetus in relevanten mengen. fehlbildungen oder andere unerwünschte effekte sind bisher weder im tierversuch noch beim menschen beobachtet worden (lewis 2003 a, sigg 2000 . pivmecillinam hat bei weit über 2.000 schwangeren, über 500 davon im 1. trimenon exponiert, weder eine erhöhte fehlbildungsrate noch andere auffälligkeiten beim neugeborenen gezeigt (vinther sriver 2004 toxikologie. weder zu erythromycin a) noch zu azithromycin, clarithromycin (einarson 1998 , josamycin, roxithromycin und spiramycin (übersicht bei briggs 2005, d) hat sich bisher ein ernsthafter verdacht auf teratogene eigenschaften beim menschen ergeben. allerdings wurde kürzlich anhand der daten des schwedischen medizinischen geburtsregisters für erythromycin eine gegenüber phenoxymethylpenicillin schwach signifikant erhöhte fehlbildungsrate bei 1.844 kindern mit einer exposition in der frühschwangerschaft beschrieben (källén 2005 e, mickal 1975 . auch zu clindamycin liegen keine entsprechenden hinweise vor. bedrohlich ist die nach mehrwöchiger behandlung bei 2-10 % der patientinnen auftretende pseudomembranöse colitis, die auch nach vaginaler clindamycinanwendung beobachtet wurde (trexler 1997). schwangerschaftskomplikationen infolge bakterieller vaginosen lassen sich durch eine vaginale clindamycintherapie nicht ausreichend verhüten (joesoef 1999 die menschliche folsäurereduktase ist sehr viel weniger empfindlich gegenüber trimethoprim als das bakterielle enzym. dies könnte erklären, dass teratogene schäden durch folsäureantagonistische antibiotika beim menschen bisher nicht nachgewiesen wurden. in einer neueren retrospektiven fall-kontroll-untersuchung wird jedoch wieder eine kausale assoziation diskutiert zwischen der therapie mit trimethoprim und anderen ebenfalls nicht onkologischen folsäureantagonisten wie carbamazepin, phenytoin, phenobarbital, primidon, triamteren und neuralrohrdefekten, kardiovaskulären fehlbildungen, lippen-gaumen-spalten und anomalien der harnwege. die autoren erörtern eine präventive gabe von multivitamin-und folsäurepräparaten (hernandez-diaz 2000) . tatsächlich hat sich der vorschlag, folsäure während einer antibiotikatherapie mit den hier besprochenen mitteln zu verabreichen, bisher aber nicht überzeugend begründen lassen. von den umfangreichen, eher beruhigenden erfahrungen der anwendung von co-trimoxazol bei banalen harnwegsinfektionen in der schwangerschaft kann nicht auf eine generelle sicherheit der therapie mit einer vielfach höheren dosis bei opportunistischen infektionen wie pneumocystis-carinii-pneumonie (pcp) im rahmen einer hiv-infektion geschlossen werden. bisher wurde nach einer solchen behandlung von schwangeren nicht über ein erhöhtes fehlbildungsrisiko berichtet. zu tetroxoprim liegen noch keine ausreichenden erfahrungen vor. (schaefer 1996) . zum gleichen ergebnis kamen auch drei andere publikationen mit kleineren fallzahlen (larsen 2001 , loebstein 1998 , berkovitch 1994 . lediglich in einem fall wurde eine neonatale hepatitis mit inkompletter intrahepatischer cholestase nach ofloxacinbehandlung der mutter in woche 15 beobachtet (wiedenhöft 2000) . die im tierversuch bei jungen hunden nach postnataler (!) behandlung beobachteten irreversiblen gelenkknorpelschäden (gough 1992) wurden bei präpartal exponierten kindern bisher nicht gesehen. pipemidsäure (deblaston ® ) und nalidixinsäure gehören zu den älteren gyrasehemmstoffen. sie erreichen nur in den ableitenden harnwegen wirksame konzentrationen. gegenüber anderen standardantibiotika haben sich diese mittel jedoch nicht durchsetzen können. hinweise auf teratogene effekte liegen nicht vor. allerdings wurde in einer retrospektiven studie mit den daten des ungarischen fehlbildungsregisters ein möglicherweise zufälliger zusammenhang zwischen pylorusstenose und der behandlung mit nalidixinsäure in der spätschwangerschaft diskutiert. das fehlbildungsrisiko war insgesamt nicht erhöht (czeizel 2001 d) . eine weitere publikation zu nalidixinsäure berichtet über den anstieg des intrakraniellen druckes beim fetus (übersicht bei . empfehlung für die praxis: gyrasehemmstoffe sind in der schwangerschaft kontraindiziert. in wohl begründeten fällen (unkomplizierte harnwegs-und atemwegsinfektionen gehören nicht dazu!), in denen besser erprobte antibiotika nicht wirksam sind, sollten nur gyrasehemmstoffe eingesetzt werden, zu denen erfahrungen an einer größeren zahl von schwangeren vorliegen, z. b. norfloxacin oder ciprofloxacin. die einnahme eines gyrasehemmstoffes rechtfertigt weder einen risikobegründeten schwangerschaftsabbruch noch invasive diagnostik (siehe kapitel 1.15). nach exposition mit einem der weniger gut untersuchten mittel dieser gruppe im 1. trimenon wird ein hoch auflösender ultraschall empfohlen. g 2.6.9 nitrofurantoin und andere harnwegstherapeutika metronidazol besitzt ein experimentell ermitteltes mutagenes und kanzerogenes potenzial (übersicht bei dobias 1994) . es bestand deshalb die befürchtung, es könne auch beim menschen mutagen oder kanzerogen wirken. bisher ließen sich derartige effekte nicht bestätigen (burtin 1995 , piper 1993 . in einer retrospektiven untersuchung wurde nach vorgeburtlicher metronidazol-exposition eine statistisch nicht signifikante assoziation mit neuroblastomen im kindesalter beobachtet (thapa 1998). eine andere über mehr als 20 jahre laufende untersuchung ergab keinen anhalt für ein erhöhtes malignomrisiko nach metronidazol-behandlung (beard 1988) . auf der grundlage von über 3.000 analysierten schwangerschaften besitzt metronidazol beim menschen kein teratogenes potenzial (diav-citrin 2001 b, caro-paton 1997 , burtin 1995 , piper 1993 . hinweise aus dem ungarischen fehlbildungsregister auf einen zusammenhang zwischen vaginaler behandlung mit metronidazol und miconazol im 2. und 3. schwangerschaftsmonat und einem vermehrten auftreten von syndaktylien und hexadaktylien haben andere untersucher bisher nicht beobachtet (kazy 2005) . die zur systemischen behandlung von trichomonaden, amöben und bakterieller vaginose benutzten mittel nimorazol (esclama ® ), ornidazol und tinidazol (simplotan ® ) sind aufgrund der spärlichen datenlage nicht ausreichend zu bewerten. bisher liegen keine hinweise auf teratogenität beim menschen vor (übersicht in . empfehlung für die praxis: metronidazol darf bei entsprechender indikation auch in der schwangerschaft angewendet werden. dies betrifft auch die systemische therapie, zumal zweifel an der wirksamkeit der vaginalen applikation bestehen. die parenterale gabe ist nur bei bedrohlichen anaerobierinfektionen angezeigt. metronidazol sollte bei der behandlung nimorazol und tinidazol vorgezogen werden. eine behandlung mit nimorazol oder tinidazol rechtfertigt jedoch weder einen risikobegründeten abbruch der schwangerschaft noch invasive diagnostik (siehe kapitel 1.15). aminoglykoside wirken ototoxisch. pränatale streptomycin-oder kanamycin-injektionen haben zu gehörschäden bei den betroffenen kindern geführt (übersicht bei . die besonders sensible phase dauert bis zum vierten schwangerschaftsmonat. auch im zusammenhang mit gentamycin wurde ein solcher fall beschrieben (sanchez-sainz-trapaga 1998). tierexperimentelle ergebnisse sprechen außerdem für eine nephrotoxizität der aminoglykoside, die sich in der fetalen niere anreichern. ein fallbericht über eine konnatale nierendysplasie nach mütterlicher therapie (hulton 1995) beweist allerdings noch kein klinisch relevantes risiko beim menschen, ebenso wenig der fall einer letal verlaufenden hydronephrose bei verdacht auf hochgradige ureterabgangsstenose nach gentamycin-therapie in schwangerschaftswoche 4 bis 5 und vorangegangener ciprofloxacin-behandlung einer harnwegsinfektion . in einer retrospektiven studie mit daten des ungarischen fehlbildungsregisters wurden keine hinweise auf teratogene effekte der aminoglykoside gefunden. in dieser studie wurden 38 schwangere ausgewertet, die mehrheitlich oral mit neomycin oder parenteral mit gentamycin behandelt worden waren (czeizel 2000 c) . empfehlung für die praxis: eine parenterale aminoglykosid-therapie darf nur bei vital bedrohlichen infektionen mit gramnegativen problemkeimen und bei versagen der für die schwangerschaft primär empfohlenen antibiotika erfolgen. die serumkonzentration muss während der therapie regelmäßig kontrolliert werden. eine aminoglykosid-behandlung rechtfertigt keinen risikobegründeten schwangerschaftsabbruch (siehe kapitel 1.15). je nach umfang einer parenteralen therapie muss die hörleistung des kindes frühzeitig kontrolliert werden. da aminoglykoside nach lokaler und oraler applikation praktisch nicht resorbiert werden, ist diese form der anwendung bei entsprechender indikation während der gesamten schwangerschaft zulässig. g 2.6.14 tuberkulostatische behandlung in der schwangerschaft eine aktive tuberkulose (tbc) muss auch in der schwangerschaft behandelt werden, weil die erkrankung nicht nur die mutter, sondern auch den fetus gefährdet. im gegensatz zu früheren mutmaßungen verschlechtert eine schwangerschaft den verlauf einer tbc nicht (davidson 1995) . zu den gebräuchlichen tuberkulostatika in der schwangerschaft zählen isoniazid (inh), rifampicin und ethambutol sowie pyrazinamid als reservemittel (american thoracic society 2003). diese mittel haben sich bisher nicht als teratogen oder fetotoxisch beim menschen gezeigt (bothamley 2001 . selbst die therapie einer multiresistenten erkrankung hat sich als gut verträglich für das ungeborene erwiesen (shin 2003 (schlagenhauf 2003) . aufgrund der zunehmenden resistenzen werden bei der malariatherapie zahlreiche kombinationen eingesetzt, vor allem mit artemisininderivaten. empfehlung für die praxis: aufgrund des umfangs an erfahrungen ist chloroquin mittel der wahl zur malariaprophylaxe in der schwangerschaft ggf. in kombination mit proguanil. falls, was zunehmend vorkommt, von beiden mitteln keine ausreichende wirksamkeit zu erwarten ist, sind die anderen mittel je nach resistenzlage anzuwenden. generell muss der beratende arzt mit der patientin erörtern, ob die reise in tropische regionen verschoben werden kann (siehe auch abschnitt 2.6.62). g 2.6.24 artemisininderivate pharmakologie und toxikologie. in einer studie zu den artemisininderivaten artesunat und artemether wurden 528 bzw. 11 dokumentierte schwangerschaftsverläufe ausgewertet, bei denen eine akute plasmodium falciparum-malaria behandelt wurde. nur bei insgesamt 44 dieser fälle fand die therapie im 1. trimenon statt (mcgready 2001) . diese und eine zweite studie mit einmaliger gabe von artesunat plus pyrimethamin-sulfadoxin bei 287 schwangeren fanden keine hinweise auf teratogenität. beim vergleich mit einer nicht exponierten kontroll-gruppe in der zweiten studie waren spontanabortrate und totgeburtenrate nicht signifikant unterschiedlich. bei 18 im 3. trimenon behandelten war das geburtsgewicht der kinder signifikant höher als in der kontrollgruppe und wurde als erfolg der antiparasitären therapie interpretiert (dean 2001 empfehlung für die praxis: chinin darf in der schwangerschaft zur therapie der chloroquinresistenten malaria tropica verwendet werden. in dieser situation ist das potenzielle behandlungsrisiko für den fetus weit geringer als die gefährdung durch die schwere mütterliche erkrankung. auf hypoglykämien muss bei der mutter geachtet werden. auch wenn embryotoxische wirkungen von chinin in analgetischen mischpräparaten nicht zu erwarten sind, sollten derartige mittel gemieden werden, da sie keiner rationalen therapie entsprechen. gleiches gilt für regelmäßigen oder exzessiven konsum von chininhaltigen getränken. g 2.6.27 chloroquin pharmakologie und toxikologie. chloroquin (z. b. resochin ® , weimerquin ® ), ein malariamittel aus der gruppe der 4-aminochinoline, verfügt über eine gute und rasche schizontozide wirkung gegen die erythrozytären formen aller plasmodienarten. in vielen malariaendemiegebieten treten zunehmend resistenzen gegen dieses recht gut verträgliche, seit vielen jahrzehnten gebräuchliche medikament auf. diese resistenzen betreffen überwiegend den erreger der schwer und häufig auch tödlich verlaufenden malaria tropica (plasmodium falciparum). aber auch bei plasmodium vivax, dem erreger der weniger schwer verlaufenden malaria tertiana, wurden resistenzen gegen chloroquin beobachtet. in der für die malariaprophylaxe üblichen dosierung und bei der 3tägigen behandlung des akuten malariaanfalls wirkt chloroquin weder embryo-noch fetotoxisch (phillips-howard 1996) . zur chloroquinbehandlung rheumatischer erkrankungen siehe abschnitt 2.12.7. empfehlung für die praxis: chloroquin kann in allen stadien der schwangerschaft zur infektionsprophylaxe und zur therapie der malaria angewendet werden, sofern eine ausreichende wirksamkeit anzunehmen ist. bei der therapie von pilzinfektionen ist die lokale therapie mit den länger gebräuchlichen substanzen auch in der schwangerschaft als ungefährlich zu betrachten. bei mykosen im genitalbereich soll gleichzeitig der partner behandelt werden. ist eine systemische therapie erforderlich, muss sorgfältig ein mittel aus dieser zumindest hypothetisch riskanten arzneimittelgruppe ausgesucht werden (sobel 2000) . in letzter zeit ist es "modern" geworden, harmlose pilzbefunde im stuhl wegen vermeintlich damit zusammenhängender, unspezifischer symptome zu behandeln. dies sollte, vor allem in der schwangerschaft, unterbleiben. g 2.6.35 clotrimazol pharmakologie und toxikologie. clotrimazol (z. b. canesten ® , canifug ® ) ist ein antimykotikum aus der gruppe der imidazolderivate. diese beeinträchtigen die ergosterolbiosynthese und führen damit bei pilzen zu störungen der zellmembranpermeabilität. clotrimazol wird prak-tisch nicht resorbiert und nur zur lokalen therapie von mykosen an haut und schleimhäuten verwendet. es gibt umfangreiche untersuchungen zur behandlung vaginaler mykosen in der schwangerschaft, aus denen sich kein embryotoxisches potenzial ableiten lässt b, king 1998 . eine verringerung der frühgeburtenrate durch lokale therapie von vaginosen mit clotrimazol wurde ebenfalls beobachtet (czeizel 1999 c) . empfehlung für die praxis: clotrimazol gehört nach nystatin zu den antimykotika der wahl in der schwangerschaft. g 2.6.36 nystatin pharmakologie und toxikologie. nystatin (z. b. candio-hermal ® , moronal ® ) ist ein bei candidainfektionen (soor) von haut und schleimhäuten wirksames antimykotikum, das nicht resorbiert wird. es wird an ergosterol in der zellmembran von pilzen gebunden und bewirkt dort eine störung der zellmembranpermeabilität. trotz breiter anwendung wurden keine hinweise auf embryo-oder fetotoxische wirkungen beobachtet (king 1998 b, czeizel 2003 b, king 1998 . der erprobungsgrad dieser mittel ist aber geringer als der des clotrimazols. hinweise aus dem ungarischen fehlbildungsregister auf einen zusammenhang zwischen vaginaler behandlung mit miconazol plus metronidazol im 2. und 3. schwangerschaftsmonat und einem vermehrten auftreten von syndaktylien und hexadaktylien wurden von anderen untersuchern bisher nicht bestätigt (kazy 2005) . empfehlung für die praxis: bifonazol, croconazol, econazol, fenticonazol, isoconazol, ketoconazol, miconazol, omoconazol, oxiconazol, sertaconazol und tioconazol sind antimykotika der zweiten wahl für eine lokale therapie. nystatin und clotrimazol sind, wo immer möglich, vorzuziehen. g 2.6.38 weitere lokal wirksame antimykotika pharmakologie und toxikologie. amorolfin (loceryl ® ), ciclopirox (batrafen ® ), naftifin (exoderil ® ), terbinafin (lamisil ® ), tolciclat und tolnaftat (z. b. tinatox ® ) sind bezüglich ihrer pränatalen toxizität beim menschen nur unzureichend untersucht. substantielle hinweise auf ein erhöhtes fehlbildungsrisiko nach lokaler anwendung liegen bisher nicht vor (sarkar 2003) . empfehlung für die praxis: eine äußerliche behandlung mit amorolfin, ciclopirox, naftifin, terbinafin, tolciclat und tolnaftat sollte in der schwangerschaft möglichst vermieden werden. eine dennoch erfolgte behandlung rechtfertigt weder einen risikobegründeten schwangerschaftsabbruch noch invasive diagnostik (siehe kapitel 1.15). nystatin und clotrimazol sollen, wo immer möglich, bevorzugt werden. g 2.6.39 "conazol-antimykotika" zur systemischen anwendung pharmakologie und toxikologie. itraconazol (z. b. sempera ® , siros ® ) und miconazol sind imidazolderivate. sie beeinträchtigen die ergosterolbiosynthese und führen zu störungen der zellmembranpermeabilität bei pilzen. im tierversuch passieren sie die fetoplazentare schranke gut. fluconazol (z. b. diflucan ® ) und ketoconazol (nizoral ® ) sind triazolderivate, deren wirkung den strukturell verwandten imidazolderivaten entspricht. im tierversuch wurden nach verabreichung sehr hoher dosen teratogene effekte beobachtet. es liegen berichte über sechs kinder mit multiplen fehlbildungen an schädel, skelett und herz vor, deren mütter wegen einer meningitis parallel zu antiretroviralen medikamenten bei hiv-infektion langfristig und hoch dosiert (400-800 mg/tag) fluconazol erhalten hatten (lopez-rangel 2005 , aleck 1997 , pursley 1996 , lee 1992 . die symptome einiger dieser kinder ähnelten dem so genannten antley-bixler-syndrom. kein anhalt für ein erhöhtes fehlbildungsrisiko fand sich hingegen in anderen prospektiven kohortenstudien und retrospektiven untersuchungen mit über 600 frauen, die in den monaten vor oder während einer schwangerschaft meist wegen vaginalmykose niedrig dosiert (150 mg/tag) mit fluconazol behandelten wurden (jick 1999 , sørensen 1999 , campomori 1997 , mastroiacovo 1996 , inman 1994 . eine vom european network of teratology information services (entis) durchgeführte prospektivstudie zu den neueren "conazol-antimykotika" ergab unter 191 schwangeren, die im 1. trimenon durchschnittlich 8 tage lang wegen vaginal-, haut-oder anderer mykosen mit fluconazol systemisch behandelt worden waren, ebenfalls keine hinweise auf ein teratogenes potenzial (vial, pers. kommunikation 2001) . die zu itraconazol vorliegenden erfahrungen mit der systemischen behandlung von vaginal-, haut-oder anderen mykosen im 1. trimenon umfassen drei prospektive kohortenstudien mit 142, 182 und 198 schwangeren (paulus, pers. mitteilung 2004 , vial, pers. kommunikation 2001 , bar-oz 2000 , aus denen sich keine hinweise auf teratogenität ergeben. das gilt auch für eine kleinere fallzahl aus einer arzneimittelverordnungsstudie (jick 1999) . die durchschnittliche behandlungsdauer in der entis-studie (vial, pers. kommunikation 2001) betrug 8 tage. ketoconazol hemmt die steroidsynthese und wird auch zur behandlung des cushing-syndroms eingesetzt. da es außerdem der bildung von testosteron entgegenwirkt, könnte die geschlechtsentwicklung männlicher feten gestört werden. derartiges wurde außerdem bisher aber nicht beobachtet. zwei schwangere mit cushing-behandlung im 2. und 3. trimenon wurden von gesunden kindern (ein junge und ein mädchen) entbunden, die auch keine nebennierenrindenanomalien aufwiesen (berwaerts 1999 , amado 1990 fallberichte beschreiben aborte und pränatal dystrophe frühgeborene. jedoch darf der mögliche einfluss der zugrunde liegenden, z. t. schweren infektionen nicht übersehen werden. auch über normale schwangerschafts-und geburtsverläufe wird berichtet. hinweise auf ein erhöhtes fehlbildungsrisiko liegen bisher nicht vor. für eine differenzierte risikobewertung der parenteralen applikation reichen die vorliegenden fallzahlen nicht aus (ely 1998 , übersicht in dean 1994 . die vereinzelt beobachteten vorübergehenden nierenfunktionsstörungen beim neugeborenen könnten durch protrahierte wirkung von arzneimitteldepots in der plazenta und im fetus erklärt werden (dean 1994) . zur neueren liposomzubereitung des amphotericin b liegt erst ein bericht mit unauffälligem ausgang vor, in dem eine schwangere im 2. trimenon wegen viszeraler leishmaniose behandelt worden war (king 1998) . empfehlung für die praxis: amphotericin b darf in der schwangerschaft nur bei bedrohlichen, generalisierten mykosen parenteral eingesetzt werden. wurde während der organogenese behandelt, rechtfertigt dies keinen risikobegründeten schwangerschaftsabbruch (siehe kapitel 1.15). in einem solchen fall sollte jedoch zur bestätigung der normalen entwicklung des fetus ein hoch auflösender ultraschall angeboten werden. die lokale anwendung ist unbedenklich. g 2.6.41 flucytosin pharmakologie und toxikologie. flucytosin (ancotil ® ) hat eine gute wirkung gegen cryptococcus neoformans und viele candidaspezies. es wird bei systemischen infektionen mit diesen erregern eingesetzt und wirkt durch hemmung der dna-synthese. in der pilzzelle wird flucytosin unter anderem zu dem zytostatikum 5-fluorouracil metabolisiert. diese reaktion ist in geringerem ausmaß auch im menschlichen organismus zu erwarten. im tierversuch wirkt flucytosin in dosen teratogen, die niedriger sind als die humantherapeutisch üblichen. fehlbildungen wurden beim menschen bisher nicht beschrieben, allerdings gibt es praktisch keine publizierten erfahrungen zur verabreichung von flucytosin im 1. trimenon. wenige erfahrungen zur anwendung im 2. und 3. trimenon bei bedrohlicher disseminierter cryptococcose erbrachten keine hinweise auf fetale störungen (ely 1998 (reuvers 2001 , cowden 2000 , ausreichende erfahrungen liegen jedoch nicht vor. in endemiegebieten wurde eine vorteilhafte wirkung auf mütterliche anämie, geburtsgewicht und neonatale sterblichkeit bei verabreichung im 2. und 3. trimenon beobachtet (christian 2004 . ein nennenswertes embryotoxisches risiko beim menschen ist nach zwei neueren studien mit 64 und 400 im 1. trimenon exponierten schwangeren nicht zu erkennen (reuvers 2001 , de silva 1999 . in einer weiteren studie wurden 5 kinder mit fehlbildungen unter 150 ausgetragenen schwangerschaften beobachtet. art und zahl der fehlbildungen weckten keinen verdacht auf teratogene effekte . tierexperimentell hat mebendazol bei der maus teratogene effekte erkennen lassen. flubendazol, dem mebendazol strukturell ähnlich, zeigte bei 150 im 1. trimenon exponierten kindern keine teratogenen eigenschaften (reuvers 2001 (chippaux 1993 , pacque 1990 , erlauben jedoch keine differenzierte risikobetrachtung. empfehlung für die praxis: ivermectin darf bei zwingender indikation auch in der schwangerschaft eingesetzt werden. g 2.6.52 aciclovir und andere herpes-virustatika pharmakologie und toxikologie. aciclovir (z. b. zovirax ® ) wirkt über eine hemmung der viralen dna-polymerase bei varizellen sowie bei herpesviren typ 1 und typ 2. bisherige erfahrungen mit mehreren tausend vom hersteller gesammelten und in der fachliteratur publizierten prospektiv oder retrospektiv erfassten verläufen, davon etwa die hälfte im 1. trimenon, lassen kein embryo-oder fetotoxisches risiko von aciclovir bei systemischer anwendung erkennen (stone 2004 , ratanajamit 2003 . dies gilt vorbehaltlich der methodischen schwächen von schwangerschaftsregistern beim arzneimittelhersteller. nach äußerlicher acicloviranwendung werden nur geringe substanzmengen resorbiert. zu famciclovir (famvir ® ), einem prodrug des penciclovir, liegen keine dokumentierten erfahrungen beim menschen vor. ganciclovir (cymeven ® ) ist tierexperimentell in dosen embryotoxisch, die den therapeutischen beim menschen entsprechen. einzelne fallberichte beschreiben einen normalen schwangerschaftsausgang nach therapie in der frühschwangerschaft (pescovitz 1999). eine fallsammlung des herstellers mit 56 mit valaciclovir (valtrex ® ) exponierten schwangeren, davon 14 im 1. trimenon, und eine fallserie mit zehn frauen, die ab woche 36 bis zur geburt behandelt wurden, zeigten keine hinweise auf embryo-oder fetotoxische schäden (glaxowellcome 1998 , kimberlin 1998 . zusammenfassend sind famciclovir, ganciclovir sowie valaciclovir und valganciclovir (ester bzw. prodrugs von aciclovir und ganciclovir) hinsichtlich ihrer verträglichkeit in der schwangerschaft unzureichend untersucht. empfehlung für die praxis: die äußerliche anwendung von aciclovir ist unproblematisch. die systemische gabe ist nur dann indiziert, wenn beispielsweise bei disseminierter herpes-oder varizellenerkrankung die mutter gefährdet ist oder wenn davon auszugehen ist, dass der fetus durch die therapie vor einer intrauterinen infektion geschützt wird. die anderen virustatika sind nur bei infektionen indiziert, bei denen sie eine therapeutische überlegenheit gegenüber aciclovir gezeigt haben. eine therapie im 1. trimenon rechtfertigt weder einen risikobegründeten abbruch der schwangerschaft noch invasive diagnostik (siehe kapitel 1.15). ein hoch auflösender ultraschall ist -mit ausnahme von aciclovir -nach anwendung im 1. trimenon zu empfehlen. g 2.6.53 amantadin pharmakologie und toxikologie. amantadin (z. b. amanta ® ) verstärkt die dopaminaktivität am rezeptor und wird deshalb als antiparkinsonmit-tel eingesetzt. als virustatikum wirkt es in erster linie gegen influenza-a-viren. im tierversuch ist amantadin in hohen dosen teratogen. beim menschen wurden verschiedene fehlbildungen nach behandlung mit amantadin beschrieben, die allerdings kein typisches muster erkennen lassen (übersicht in . andererseits erlauben die ebenfalls dokumentierten unauffälligen verläufe keinen ausschluss eines teratogenen risikos. empfehlung für die praxis: amantadin ist in der schwangerschaft kontraindiziert. wurde während der organogenese behandelt, rechtfertigt dies keinen risikobegründeten schwangerschaftsabbruch (siehe kapitel 1.15). in einem solchen fall sollte jedoch zur bestätigung der normalen entwicklung des fetus ein hoch auflösender ultraschall angeboten werden. g 2.6.54 ribavirin pharmakologie und toxikologie. ribavirin (z. b. rebetol ® , virazole ® ) hat experimentell ein breites antivirales spektrum, die klinische relevanz ist jedoch begrenzt. es wird u. a. bei rs-viruserkrankungen im säuglingsalter und in kombination mit § -interferonen bei hepatitis c eingesetzt. im tierversuch ist ribavirin bei mehreren spezies teratogen und wirkt experimentell mutagen. die kinder von 9 schwangeren, die in der zweiten schwangerschaftshälfte wegen schwerer masernverläufe behandelt worden waren, wiesen keine fetotoxischen effekte auf (atmar 1992). über weitere 5 fälle mit einer behandlung in der spätschwangerschaft und einen fall mit prophylaktischer intramuskulärer verabreichung von 3 injektionen im 1. trimenon wegen sars (severe acute respiratory syndrome) wird berichtet (rezvani 2006 g 2.6.56 hiv-therapie und prophylaxe in der schwangerschaft das ziel einer antiretroviralen therapie (art) in der schwangerschaft ist einerseits die verhinderung der mutter-kind-übertragung von hiv, andererseits die optimale behandlung der schwangeren bei möglichst geringen unerwünschten wirkungen der medikamente auf die schwangere und das ungeborene kind. unumstritten ist der protektive wert einer perinatalen prophylaxe mit dem nucleosidanalogen reverse-transkriptase-inhibitor (nrti) zidovudin zur vermeidung der vorwiegend unter der geburt möglichen mutter-kind-übertragung (vertikale transmission) von hiv (connor 1994 pharmakologie und toxikologie. zidovudin (retrovir ® ), auch als azidothymidin (azt) bezeichnet, ist das älteste zur antiretroviralen therapie (art) eingesetzte virustatikum. es hemmt als nukleosidanaloger reverse-transkriptase-inhibitor (nrti) kompetitiv die vermehrung von hiv-1-und hiv-2-viren. zidovudin ist gut plazentagängig, die nachgewiesene metabolisierung in der plazenta erklärt möglicherweise den transmissionshemmenden effekt der substanz. die bisher vorliegenden erfahrungen mit mehreren 1.000 dokumentierten schwangerschaftsverläufen sprechen gegen ein nennenswertes teratogenes potenzial (watts 2004, mofenson 2000) . nach den daten des antiretroviral pregnancy registry war die fehlbildungsrate mit 2,8% nicht erhöht. es wird diskutiert, ob zidovudin und andere nrtis mitochondriale dysfunktionen verursachen können. blanche und mitarbeiter (1999) berichten über 8 nicht hivinfizierte kinder mit solchen auffälligkeiten, die intrauterin und nach der geburt mit zidovudin allein oder zusammen mit lamivudin exponiert waren. zwei der kinder starben noch im säuglingsalter, 3 weitere wiesen eine neurologische symptomatik auf (blanche 1999) . andere kohortenstudien konnten diese medikamenteninduzierten mitochondriopathien nicht bestätigen. tierexperimentelle befunde an affen ergaben strukturelle und funktionelle störungen der mitochondrienfunktion in herz-und skelettmuskelzellen der jungtiere, nachdem die muttertiere beim menschen übliche zidovudindosen erhalten hatten. ent-sprechende herzanomalien konnten bei pränatal exponierten kindern nicht nachgewiesen werden. in einer prospektiven studie fand sich bei mit zidovudin exponierten kindern, die bis zum alter von 5 jahren echokardiographisch untersucht wurden, kein hinweis auf kardiale toxizität (lipshultz 2000) . die einzige wiederholt beobachtete auffälligkeit bei neugeborenen nach intrauteriner zidovudinexposition ist das auftreten einer vorübergehenden anämie, die sich innerhalb der ersten 12 lebenswochen normalisiert (sperling 1998 , connor 1994 . in einer nachsorgestudie von 234 kindern des pediatric aids clinical trials group protocol 076 (pactg 076) zeigten kinder mit einer intrauterinen zidovudinexposition keine auffälligkeiten ihrer körperlichen, immunologischen und kognitiven parameter bis zum 6. lebensjahr (curlane 1999). es fanden sich auch keine hinweise auf tumorbildung bei über 700 prä-und perinatal exponierten kindern (curlane 1999 , hanson 1999 (graham 2005 , edwards 1995 . auch beim menschen wurde dies immer wieder erörtert. es gibt hinweise darauf, dass verschiedene anomalien, wie z. b. neuralrohrdefekte (suarez 2004 , shaw 1998 ), aber auch nieren-, herz-und bauchwandfehlbildungen (abe 2003 , chambers 1998 nach fieberhaften infekten in der frühschwangerschaft häufiger auftreten. moretti und mitarbeiter (2005) haben in einer meta-analyse zum risiko von neuralrohrdefekten nach hyperthermie insgesamt 15 studien mit 1.719 fällen ausgewertet und sowohl in den 9 einbezogenen fall-kontroll-studien als auch in 6 kohorten-studien signifikante assoziationen mit einem odds ratio von etwa 1,9 ermittelt. abe und mitarbeiter (2003) haben in einer retrospektiven studie mit wenigen dutzend betroffenen schwangeren schwache signifikanzen sowohl für fieber als auch generell für infekte im 1. trimenon ermittelt. chambers und mitarbeiter (1998) diskutiert wird u. a., dass hohe körpertemperaturen vaskuläre störungen verursachen können, so dass die sich entwickelnden organe vorübergehend nicht ausreichend durchblutet werden (graham 1998 ). suarez und mitarbeiter (2004) haben in ihrer retrospektiven studie, die 184 von neuralrohrdefekten betroffene familien sowie gesunde kontrollen einschließt, ein geringeres risiko bei einnahme fiebersenkender medikamente beobachtet. es fanden sich auch schwache signifikanzen bei anderen potenziell zur überwärmung führenden faktoren, wie z. b. heizdecken, sauna und kochen in überwärmter küche während des 1. andere untersuchungen belegen kein erhöhtes risiko durch saunen, obwohl schon nach 10-20 minuten die körpertemperatur auf über 38,5°c steigen kann. in finnland, wo dieser frage nachgegangen wurde, ist häufiges saunen auch während der schwangerschaft üblich. auch der gebrauch elektrischer heizdecken und geheizter wasserbetten hat bei anderen untersuchern kein signifikant erhöhtes fehlbildungsrisiko erkennen lassen. eine weitere studie hat bei kindern im alter von 5 und 12 jahren häufiger defizite im emotionalen und kognitiven bereich beobachtet, wenn im 2. oder 3. trimenon fieber berichtet wurde (dombrowski 2003 die durch impfstoffe angeregte spezifische immunität der mutter schützt auch das kind durch diaplazentaren übergang der mütterlichen igg-antikörper. bisher haben sich für keinen impfstoff entwicklungstoxische eigenschaften gezeigt und bei keinem lebendimpfstoff hinweise auf eine infektionsbedingte schädigung des ungeborenen. der umfang an dokumentierten erfahrungen ist jedoch für die einzelnen impfstoffe sehr unterschiedlich. generell sollten routineimpfungen in der schwangerschaft, insbesondere solche mit lebendimpfstoffen, unterbleiben. besteht aber ein erkennbares expositionsrisiko und liegt kein impfschutz vor, kann und muss ggf. auch während der schwangerschaft im interesse von mutter und kind geimpft werden (siehe unter den jeweiligen impfstoffen). mehr oder weniger detailliert wird in verschiedenen impfempfehlungen auf schwangere eingegangen (z. b. empfehlungen der ständigen impfkommission -stiko). bei fragestellungen zum risiko von tropischen impfungen und malariaprophylaxe in der schwangerschaft sollten auch die allgemeinen risiken von fernreisen mit der schwangeren erörtert werden (siehe abschnitt 2.6.62). wenn eine impfung tatsächlich indiziert ist, muss diese selbstverständlich auch in der schwangerschaft durchgeführt werden. , silveira 1995 . auch konnte kein zusammenhang mit fehlgeburten beobachtet werden. catindig und mitarbeiter (1996) nach impfung mit dem fsme-impfstoff haben sich bisher keine hinweise auf entwicklungstoxische effekte beim menschen gezeigt. empfehlung für die praxis: da dieser impfstoff nicht systematisch untersucht ist, sollte während einer schwangerschaft die impfindikation kritisch geprüft werden. g 2.7.4 gelbfieberimpfung der gelbfieberimpfstoff enthält einen abgeschwächten lebendimpfstoff. ein fallbericht beschreibt eine gelbfieberinfektion beim neugeborenen im zusammenhang mit einer impfung im 1. trimenon (tsai 1993) . dieser befund wurde von anderer seite nicht bestätigt. in einer untersuchung an 101 geimpften schwangeren, davon vier im 1. und 89 im 3. trimenon, erbrachte keine entwicklungsauffälligkeiten bei den kindern bis zum alter von 3-4 jahren (nasidi 1993) . eine leicht erhöhte spontanabortrate wird in einer anderen, allerdings sehr kleinen retrospektiven studie mit 39 schwangeren beschrieben (nishioka 1998) . unter 58 im 1. trimenon geimpften wurde keine konnatale infektion und kein hinweis auf teratogene effekte gefunden . bisherige erfahrungen sprechen also gegen ein nennenswertes entwicklungstoxisches risiko der impfung. empfehlung für die praxis: da gelbfieber im erkrankungsfall lebensbedrohlich sein kann, muss eine schwangere bei unaufschiebbarer reise in ein endemiegebiet auch im 1. trimenon geimpft werden (american college of obstetricians and gynecologists 1993). g 2.7.5 bisher publizierte fallserien mit mehr als 2.000 frauen, die kurz vor oder während der schwangerschaft geimpft wurden, ergeben keine hinweise auf eine entwicklungstoxische wirkung dieses inaktivierten impfstoffs (munoz 2005 , deinhard 1981 . der fall einer zns-fehlbildung nach impfung in woche 6 (sarnat 1979) wurde von anderen untersuchern nicht bestätigt. das us-amerikanische "advisory committee on immunization practices of the centers for disease control" empfahl 2004, schwangere während der grippesaison aufgrund möglicher influenzabedingter komplikationen unabhängig vom trimenon zu impfen. empfehlung für die praxis: wenn andere beeinträchtigende faktoren, wie z. b. asthma, vorliegen oder in der vorgeschichte wiederholt von influenzainfektionen berichtet wird, sollten schwangere geimpft werden, ggf. auch im 1. trimenon. g 2.7.6 systematische untersuchungen zur pränataltoxizität dieses inaktivierten impfstoffs liegen nicht vor. ein passiver schutz vor einer möglicherweise bedrohlichen infektion im säuglingsalter ist durch diaplazentaren übertritt mütterlicher antikörper nach impfung der mutter im 3. trimenon möglich (glezen 1999) . empfehlung für die praxis: eine impfempfehlung für schwangere wird zurzeit noch diskutiert. g 2.7.7 als hepatitis-b-impfstoff wird ein biotechnologisch hergestelltes, nicht vermehrungsfähiges oberflächenantigen eingesetzt. die bisher publizierten verläufe nach impfungen von über 150 schwangeren zeigten keine unerwünschten wirkungen beim fetus (ingardia 1999 , reddy 1994 , grosheide 1993 . bei nahezu 90 % der schwangeren mit serokonversion nach einer impfung während der schwangerschaft wurden auch im nabelschnurblut protektive antikörperkonzentrationen gefunden (ingardia 1999) . systematische untersuchungen zum hepatitis-a-impfstoff in der schwangerschaft liegen nicht vor. wahrscheinlich ist dieser totimpfstoff ähnlich zu beurteilen wie der hepatitis-b-impfstoff. (boettiger 1997) . die rötelnimpfung wird mit dem zurzeit gebräuchlichen abgeschwächten lebendimpfstoff ra 27/3 durchgeführt. dieser ist auch in den kombinationsimpfstoffen mit masern und mumps (mmr) enthalten. der rötelnimpfvirus ist plazentagängig und kann den fetus infizieren. bei 2,7 % bis 7,7 % (durchschnitt 4,1 %) in der frühschwangerschaft geimpfter fällt später der nachweis von rötelnspezifischen igm-antikörpern im nabelschnurblut beim neugeborenen positiv aus (enders 2005) . in einem fall wurde eine persistierende subklinische infektion beobachtet (hofmann 2000) . in ca. 3-20 % konnte das impfvirus nach impfung aus abortmaterial isoliert werden , center for disease control 1989 . die einzelfalldarstellung eines angeborenen katarakts nach mütterlicher impfung konnte nicht durch andere untersucher bestätigt werden (fleet 1974) . berichte über insgesamt 718 schwangerschaften aus deutschland, schweden, england und den usa wurden bisher publiziert, bei denen seronegative frauen im zeitraum von 3 monaten vor konzeption bis in die schwangerschaft hinein versehentlich mit unterschiedlichen rötelnlebendimpfstoffen geimpft wurden (enders 2005 . im zeitraum mit theoretisch hohem risiko, also ein bis 2 wochen vor bis 6 wochen nach konzeption, wurden 326 der 718 schwangeren geimpft. es wurde dabei keine rötelnembryopathie beobachtet. dies spricht dafür, dass eine impfbedingte schädigung sehr unwahrscheinlich ist. rein statistisch kann man mit einer solchen fallzahl jedoch nur ausschließen, dass das risiko größer als 0,5 % (95 % konfidenzintervall) ist. empfehlung für die praxis: eine rötelnimpfung sollte unmittelbar vor und während der schwangerschaft nicht durchgeführt werden. bisherige erfahrungen sprechen gegen ein risiko für rötelnembryopathie durch impfung. daher ergeben sich aus einer versehentlichen impfung keine konsequenzen wie schwangerschaftsabbruch oder invasive diagnostik. ob eine seronegative schwangere mit hohem expositionsrisiko gegenüber röteln auch während der schwangerschaft geimpft werden sollte, muss individuell entschieden werden. g 2.7.14 tollwutimpfung der tollwutimpfstoff enthält einen abgeschwächten lebendimpfstoff, der aus menschlichen zellkulturen gewonnen wird. der heute zur verfügung stehende impfstoff ist im gegensatz zu früheren tollwutimpfstoffen gut verträglich. fallberichte zur aktiven und/oder passiven impfung bei über 200 schwangeren zeigen keine auffälligkeiten (chutivongse 1995 , chabala 1991 , fescharek 1990 ). die mütterlichen antikörper scheinen die plazenta zu überwinden. empfehlung für die praxis: da tollwut eine tödlich verlaufende erkrankung ist, muss eine schwangere nach einem tollwutverdächtigen tierbiss immer simultan (aktiv und passiv) geimpft werden. g 2.7.15 typhusimpfung es gibt zwei typhusimpfstoffe: die parenteral zu verabreichende inaktivierte typhusvakzine und den oralen typhus-lebendimpfstoff mit salmonella typhi typ 21a. der lebendimpfstoff schützt nicht gegen paratyphus a und b, weist aber eine geringere nebenwirkungsrate auf als die inaktivierte vakzine. bei einer typhuserkrankung in der schwangerschaft ist durch die typhöse septikämie das abortrisiko erhöht. deshalb ist auch für schwangere der schutz vor einer infektion ratsam, vor allem bei einem längeren aufenthalt in entsprechenden ländern. eine untersuchung mit rund 20 schwangeren, die den lebendimpfstoff im 1. trimenon erhielten, erbrachte keine spezifischen auffälligkeiten (mazzone 1994) . bei entsprechender indikation darf eine schwangere geimpft werden. die erstinfektion mit varizellen in der schwangerschaft kann in etwa 1 % der fälle zu schäden beim embryo bzw. fetus führen. dieser verdacht hat sich bisher aber nicht nach impfung mit diesem lebendimpfstoff ergeben. bei 530 vom hersteller prospektiv dokumentierten schwangerschaften (merck/cdc pregnancy registry 2004) wurden insgesamt 11 fehlbildungen unter 507 lebendgeborenen beobachtet (2,2 %), unter den 120 seronegativen waren es 5 (4,2 %) und begrenzt auf die seronegativen mit impfung im 1. oder 2. trimenon 5/80 (6,3 %). diese fehlbildungsraten wurden als nicht statistisch signifikant erhöht bewertet. außerdem war keine varizellenembryopathie unter den fehlbildungen. empfehlung für die praxis: während einer schwangerschaft sollte nicht geimpft werden. bei dennoch erfolgter anwendung sind keine konsequenzen erforderlich. g 2.7.17 immunglobuline immunglobulinlösungen enthalten hauptsächlich immunglobulin-g-(igg-)antikörper und werden aus gepooltem menschlichem plasma hergestellt. das ausmaß der plazentapassage von igg-antikörpern ist abhängig vom gestationsalter, der dosierung, der dauer der behand-lung und der art des verabreichten präparates. immunglobuline kommen bei sehr unterschiedlichen mütterlichen oder fetalen indikationen zum einsatz, z. b. bei antikörpermangel, bei infektionserkrankungen (insbesondere zur prävention), bei autoimmunkrankheiten zur besserung der symptome bei der mutter oder bei der behandlung fetaler krankheitssymptome, wie z. b. dem fetalen herzblock bei mütterlichem lupus erythematodes. sowohl immunglobuline als auch hyperimmunseren gegen spezifische infektionen wirken nach heutiger erkenntnis nicht embryotoxisch. unspezifische risiken durch menschliche blutprodukte wie die übertragung von virusinfektionen und anaphylaxie sind nicht völlig auszuschließen und könnten mittelbar auch den fetus gefährden. eine untersuchung an 93 kindern von müttern, die gammaglobulin zur hepatitisprophylaxe während der schwangerschaft erhalten hatten, beschreibt signifikant gehäufte veränderungen der hautlinien an den fingerkuppen der pränatal exponierten kinder (ross 1996) . diese kaum als fehlbildungen zu bewertenden effekte traten nur dann auf, wenn die exposition in den ersten 162 tagen der schwangerschaft erfolgte. dieser bericht ist eher als anekdotisch zu betrachten. empfehlung für die praxis: standard-gammaglobulin und hyperimmunseren dürfen bei gegebener indikation auch während der schwangerschaft verabreicht werden. g 2.7.18 thiomersalhaltige impfstoffe die früher in manchen impfstoffen als konservierungsstoff enthaltenen mengen an thiomersal bzw. ethylquecksilber (ca. 5 ? g) sind kürzlich als gefahrenpotenzial diskutiert worden (bigham 2005 , clements 2003 ). bei genauerer betrachtung ergab sich, dass die mengen an ethylquecksilber, zumal nach einmaliger verabreichung, sehr gering sind. ein vergleich mit dem für den menschen riskanteren methylquecksilber muss berücksichtigen, dass dieses die blut-hirn-schranke leichter überwindet. bisher liegen keine fallberichte vor, die den verdacht einer pränatalen schädigung durch eine thiomersalhaltige impfung begründen. dies erscheint plausibel, wenn man andere situationen mit erhöhter quecksilberbelastung zum vergleich heranzieht, wie die in manchen ländern höhere "hintergrundbelastung" mit quecksilber durch regelmäßigen verzehr kontaminierter fische. die who empfiehlt thiomersalhaltige impfstoffe für die so genannte dritte welt, da sie dort leichter verfügbar, billiger, sicherer und wirksamer sind (bigham 2005 ). während der schwangerschaft kommt es zu gravierenden hämodynamischen veränderungen. ab schwangerschaftswoche 5 nimmt das blutvolumen zu, am ende der schwangerschaft beträgt die steigerung 50 %. sowohl gefäßwiderstand als auch blutdruck sinken, und der ruhepuls steigt um 10-20 schläge pro minute. daraus resultiert ein 30-50 %iger anstieg herzminutenvolumens. während der geburt kommt es zu einer weiteren zunahme des auswurfvolumens und der blutdruck steigt. im allgemeinen werden ein bis drei tage nach geburt, manchmal auch erst nach einer woche, die hämodynamischen ausgangswerte erreicht (oakley 2003) . während herzkrankheiten in der schwangerschaft selten sind (unter 1 %), kommen behandlungsbedürftige hypertone und hypotone regulationsstörungen häufiger vor. g 2.8.1 bei den hochdruckkrankheiten schwangerer unterscheidet man folgende formen: 7 chronische hypertonie (mit oder ohne proteinurie), die vor, während oder nach der schwangerschaft diagnostiziert wird. 7 präeklampsie, eklampsie: proteinurie ( g 300 mg/24 h) und neu aufgetretene hypertonie (fakultativ: ödeme). 7 pfropfgestose: präeklampsie bei schwangeren mit chronischer hypertonie (häufigkeit: bei 20-25 % der schwangeren mit chronischer hypertonie). 7 schwangerschaftshochdruck: eine nach 20 schwangerschaftswochen entstehende hypertonie ohne proteinurie, die sich spätestens 12 wochen nach der entbindung zurückbildet. ungefähr die hälfte dieser schwangeren entwickelt eine präeklampsie. ein blutdruckwert von 140/90 mmhg gilt als grenzwert für eine hypertonie in der schwangerschaft. patientinnen haben ein niedriges risiko, wenn die werte im grenzbereich liegen, wenn sie keine auffälligkeiten bei der körperlichen untersuchung bieten, ein normales ekg und echokardiogramm aufweisen und keine proteinurie besteht. eine antihypertensive therapie von schwangeren mit blutdruckwerten bis 160/110 mmhg stellt keinen vorteil für den schwangerschaftsverlauf und das befinden der mutter dar, so dass eine medikamentöse behandlung nicht indiziert ist. komplikationen schwerer hypertoner zustände sind hirnblutungen der mutter oder kardiale probleme. vor allem über eine plazentadysfunktion sind abruptio der plazenta, frühgeburt, wachstumsretardierung und perinataler tod assoziiert. das risiko für eine schwangere und das werdende kind ist bei einer hypertonie mit gefäß-bzw. organschäden, mit kardiovaskulären begleiterkrankungen und/oder mit proteinurie, das heißt bei jeder form der präeklampsie, als hoch einzuschätzen. man nimmt an, dass die präeklampsie auf einer gestörten interaktion zwischen trophoblastinvasion und dezidua beruht. die daraus folgende mangelnde dilatation der spiralarterien kann zur plazentaren hypoperfusion führen. eine kausale therapie außer der geburt gibt es nicht. blutdrucksenkung bei diastolischen werten g 110 mmhg und die gabe von 100 mg/tag acetylsalicysäure sind möglichkeiten einer konservativen therapie, die nur unter strikter kontrolle der fetoplazentaren einheit erfolgreich sein kann. das hellp-syndrom (hämolyse, erhöhte leberwerte, erniedrigte thrombozytenzahl) beinhaltet zusätzliche risiken für mutter und fetus. eine große prospektive studie mit fast 2.000 hypertensiven schwangeren bestätigt, dass das fetale risiko bei präeklampsie und pfropfgestose deutlich höher ist als bei den beiden anderen hypertonieformen (ray 2001) . welche klinische bedeutung der in-vitro-untersuchung von houlihan (2004) zukommt, muss offen bleiben: labetalol, hydralazin, nifedipin und magnesiumsulfat haben einen signifikant relaxierenden effekt auf die nabelarterie, dagegen führt methyldopa zu keiner änderung des gefäßwiderstandes. eine metaanalyse zu möglichen änderungen der fetalen und neonatalen herzfrequenz bei mütterlicher antihypertensiver medikation kommt zu dem schluss, dass die vorliegenden daten zu nifedipin, hydralazin, labetalol und methyldopa zu ungenau für eine endgültige aussage sind (waterman 2004). die auswahl antihypertensiver medikamente unterscheidet sich von einer behandlung außerhalb der schwangerschaft. trotz vielfältiger untersuchungen und erfahrungen gibt es jedoch nach wie vor keine einheitlichen empfehlungen für schwangere. systematische kontrollierte studien mit großer fallzahl und exposition im 1. trimenon sind rar. als langzeitantihypertensivum bei chronischer hypertonie kommt in erster linie methyldopa infrage. mittel der zweiten wahl sind metoprolol, dihydralazin/hydralazin und nifedipin. bei den mutter und fetus mehr gefährdenden, durch präeklampsie bedingten hochdruckformen haben sich dihydralazin, nifedipin und urapidil bewährt. auch g -rezeptorenblocker können gegeben werden, von denen das in deutschland nicht zur verfügung stehende labetalol am besten untersucht ist. hypertensive erkrankungen in der schwangerschaft erfordern vor allem eine spezialisierte diagnostik, die dann eine ggf. indizierte therapie begleiten bzw. steuern kann. pindolol (visken ® ) neben einer g 1 -auch eine g 2 -blockierende wirkung. gute erfahrungen werden auch mit labetalol beschrieben, das eine zusätzliche § -rezeptor-blockierende komponente besitzt. alle g -rezeptorenblocker passieren die plazenta. nach heutiger erkenntnis haben sie keine teratogenen eigenschaften. zwar gibt es einen bericht zu 105 neugeborenen, die im 1. trimenon atenolol exponiert waren und von denen 12 kinder große fehlbildungen aufwiesen. die uneinheitlichkeit dieser fehlbildungen sowie die ergebnisse anderer untersuchungen sprechen aber gegen einen ursächlichen zusammenhang . in unserem pharmakovigilanzzentrum konnten wir bisher mehr als 200 schwangerschaften prospektiv nachverfolgen, die im 1. trimenon metoprolol exponiert waren. unter 175 lebend geborenen kindern wiesen 7 grobstrukturelle fehlbildungen auf (4 %): je zwei fälle mit gaumenspalte und vorhofseptumdefekt, je ein fall mit einer stenose der a. pulmonalis, einer zwerchfellhernie und einer polyzystischen niere. atenolol kann zu einem geringeren gewicht der plazenta, einer intrauterinen wachstumsverzögerung und einem geringeren geburtsgewicht führen (tabacova 2003). diskutiert wird, dass andere g -rezeptorenblocker dieselben symptome verursachen können (magee 2003) . es ist nicht endgültig geklärt, welchen anteil an der möglicherweise zugrunde liegenden plazentaren perfusionsminderung atenolol (oder ein anderer g -rezeptorenblocker) oder der behandlungsbedürftige hypertonus hat. g -rezeptorenblocker erhöhen -wenn auch nur sublim -den tonus des uterus und können auf diese weise die perfusion reduzieren. auch die blutzuckersenkende wirkung der betablocker wird als ursache diskutiert. das postnatale wachstum im ersten lebensjahr ist offenbar ebenso wenig beeinträchtigt wie die übrige entwicklung der kinder (reynolds 1984). bayliss (2002) untersuchte 491 schwangerschaften mit hypertonie, dabei wurde in 302 fällen mindestens ein antihypertensivum eingenommen. 189 unbehandelte schwangere dienten als kontrollgruppe. das ergebnis ist interessant: nur die neugeborenen, deren mütter atenolol zur konzeption oder ab dem 1. trimenon (n=40) bis zur geburt eingenommen hatten, wiesen ein statistisch signifikant niedrigeres geburtsgewicht auf. atenolol im 2. trimenon führte nicht zu diesem effekt. unabhängig vom eingenommenen antihypertensivum stand eine pfropfgestose (im 2/3. trimenon) in zusammenhang mit einem geringeren geburtsgewicht. bei einem kind wird eine retroperitoneale fibromatose mit medullärer kompression und später resultierender skoliose in zusammenhang mit der mütterlichen atenololtherapie beschrieben. die autoren halten diese assoziation für erwähnenswert, da analoge befunde bei erwachsenen nach atenololexposition beschrieben wurden (satgé 1997). zu sotalol siehe abschnitt 2.8.17. es gibt keine ausreichenden erfahrungen zu alprenolol, betaxolol . ein nennenswertes teratogenes risiko ist auch bei diesen g -rezeptorenblockern unwahrscheinlich. eine neonatale g -rezeptorenblockade infolge mütterlicher therapie ist theoretisch bei jeder substanz zu erwarten und kann sich in erniedrigter herzfrequenz und hypoglykämie äußern. ein fallbericht beschreibt sogar unter augentropfenanwendung von 0,5 %igem timolol eine fetale bradykardie und arrhythmie bei 21 schwangerschaftswochen, die sich unter dosishalbierung und anschließendem absetzen besserte (wagenvoort 1998). weitere fälle wurden trotz häufiger glaukombehandlung mit diesen mitteln in der schwangerschaft nicht berichtet. atemdepression bei neugeborenen wurde unter intravenöser gabe von propranolol kurz vor der schnittentbindung beobachtet (überblick in , ist aber eher eine ausnahmeerscheinung. ein absetzen der medikation 24-48 stunden vor der entbindung wird von manchen autoren erörtert. dieses vorgehen ist kaum zu rechtfertigen. die meist nur milden symptome einer g -rezeptorenblockade bessern sich beim neugeborenen innerhalb von 48 stunden folgenlos. dennoch sollten sich geburtshelfer und pädiater über die mütterliche medikation informieren. die verstärkung vorzeitiger wehentätigkeit durch g -rezeptorenblocker ist theoretisch denkbar. es wurde jedoch bei gabe von g 1 -rezeptorenblockern während einer tokolyse mit g 2 -sympathomimetika kein negativer einfluss auf die wehenhemmung beschrieben (trolp 1980). insgesamt muss davon ausgegangen werden, dass ein den blutzucker senkender effekt einerseits und eine leicht erhöhte uteruswandspannung andererseits basis des immer wieder beobachteten geringeren geburtsgewichts sind. empfehlung für die praxis: g -rezeptorenblocker gehören zu den antihypertensiva der wahl in der schwangerschaft, wobei erprobte mittel wie metoprolol zu bevorzugen sind. atenolol sollte eher nicht verordnet werden. timolol darf zur glaukombehandlung in der gesamten schwangerschaft angewendet werden. eine therapie mit atenolol oder wenig untersuchten g -rezeptorenblockern rechtfertigt weder einen risikobegründeten schwangerschaftsabbruch noch invasive diagnostik (siehe kapitel 1.15). eine gewichtsrestriktion des fetus durch einnahme von g -rezeptorenblockern durch die mutter ist möglich. mit perinatalen auswirkungen wie herzfrequenzabnahme und hypoglykämie muss bei allen g -rezeptorenblockern gerechnet werden, wenn bis zur geburt behandelt wurde. in einzelnen fällen wurden nach gabe von § -methyldopa während der schwangerschaft hepatotoxische effekte beobachtet (smith 1995) . einer weiteren untersuchung zufolge kann bei neugeborenen nach präpartaler behandlung der mutter in den ersten beiden lebenstagen ein um 4-5 mmhg erniedrigter blutdruck auftreten, der jedoch klinisch keine relevanz besitzt (whitelaw 1981). § -methyldopa hatte in einer in-vitro-untersuchung keinen einfluss auf den gefäßwidersand der nabelarterie (houlihan 2004). günenç (2002) analysierte mit hilfe der dopplersonographie den effekt von methyldopa bei 24 schwangeren mit präeklampsie. der gefäßwiderstand der arteria uterina wurde durch die therapie herabgesetzt, jedoch nicht von nabelarterien oder fetaler arteria cerebri media. empfehlung für die praxis: § -methyldopa ist eines der ältesten antihypertensiva, das auch in der schwangerschaft für mutter und ungeborenes gut verträglich ist. es ist das mittel der 1. wahl bei chronischer hypertonie in der schwangerschaft. signifikante unterschiede zur kontrollgruppe ergaben sich bei der frühgeburtsrate. ferner ließ sich sowohl bei den früh geborenen als auch bei den reif geborenen kindern in einigen der zentren eine tendenz zu einem geringeren geburtsgewicht feststellen. diese effekte sind am ehesten durch die art und schwere der meist zugrunde liegenden plazentaren störungen zu erklären und nicht durch die medikamentenexposition (weber-schöndorfer 2004) . nifedipin sollte nicht in kombination mit magnesium i.v. gegeben werden (vetter 1991 , waismann 1988 , da dies zu gravierendem blutdruckabfall mit fetaler hypoxie oder bradykardie führen kann. nifedipin kann auch nach sublingualer anwendung zur rapiden blutdrucksenkung führen (hata 1995). gute erfahrungen wurden mit nifedipin als tokolytikum gemacht (siehe abschnitt 2.14.6). khandelwal (2002) berichtet über 7 schwangere mit chronischer nierenerkrankung und proteinurie, von denen 4 diltiazem im 2./3. trimenon einnahmen. die autoren diskutieren diltiazem als alternative zu den in der schwangerschaft kontraindizierten angiotensin-ii-rezeptor-antagonisten. verapamil, mit dem auch fetale supraventrikuläre tachykardien behandelt werden, kann hyperprolaktinämie und galaktorrhö verursachen (siehe auch unter antiarrhythmika abschnitt 2.8.17). zusammenfassend ergeben sich aus den bisherigen publikationen keine hinweise auf ein nennenswertes teratogenes risiko beim menschen. empfehlung für die praxis: calciumantagonisten gehören zu den antihypertensiva der 2. wahl in der schwangerschaft, wobei erprobte mittel wie nifedipin und als antiarrhythmikum verapamil (siehe dort) zu bevorzugen sind. eine therapie mit einem weniger gut untersuchten calciumantagonisten im 1. trimenon rechtfertigt weder einen risikobegründeten schwangerschaftsabbruch noch invasive diagnostik (siehe kapitel 1.15). eine hoch auflösende ultraschallfeindiagnostik kann aber zur bestätigung der normalen entwicklung des fetus angeboten werden. sind antihypertensiva, die das angiotensin konvertierende enzymsystem hemmen (ace-hemmstoffe). sie haben inzwischen eine starke verbreitung bei der behandlung des bluthochdrucks erfahren. zu captopril und enalapril liegen die meisten erfahrungen vor. es gibt nur wenige fallberichte zu anderen ace-hemmstoffen wie lisinopril (tomlinson 2000) . in den bisher publizierten fallserien mit über 200 im 1. trimenon behandelten schwangeren und weiteren über 450 von uns und anderen teratologischen zentren in europa dokumentierten schwangerschaften zeigten sich keine eindeutigen hinweise auf teratogene effekte beim menschen , burrows 1998 , bar 1997 . eine methodisch kritisch zu bewertende verschreibungsstudie fand ein von anderen untersuchern bisher nicht bestätigtes erhöhtes fehlbildungsrisiko u. a. für herzseptumdefekte (cooper 2006 seit längerem ist bekannt, dass ace-hemmstoffe in der zweiten schwangerschaftshälfte zur mangeldurchblutung der plazenta (de moura 1995), zu fetaler hypotonie, oligohydramnion und dialysepflichtiger anurie beim neugeborenen führen können (murki 2005 , filler 2003 , lavoratti 1997 . der pathomechanismus ist folgender: die fetale nieren-und urinproduktion beginnt ende des 1. trimenons. ace-inhibitoren setzen den gefäßtonus der nierengefäße herab, so dass es zu einer reduzierten urinproduktion kommt. daraus resultiert ein oligohydramnion, da nach schwangerschaftswoche 16 die fetale urinproduktion die hauptquelle für die amnionflüssigkeit ist. eine hypoxämisch bedingte dysgenesie der nierentubuli wurde beobachtet (prasad 2003) . eine hypoplasie der schädelknochen kann als folge einer minderperfusion und des durch das oligohydramnion bedingten erhöhten druckes auf den schädel beobachtet werden (barr 1994) . derartige entwicklungsstörungen wurden auch tierexperimentell unter hoher dosis beobachtet. es gibt fallbeschreibungen zur rückbildung eines oligohydramnions nach absetzen des ace-hemmstoffes (muller 2002) . inwieweit die nach gabe von ace-hemmstoffen beobachteten spontanaborte, intrauterinen fruchttode und frühgeburten mit atemnotsyndrom medikamentenbedingt oder dem behandelten schweren hypertonus zuzuordnen sind, ist nicht geklärt. das gilt auch für die fälle des persistierenden ductus arteriosus, der theoretisch mit durch arzneimittel verursachte erhöhte bradykininkonzentrationen erklärt werden könnte. empfehlung für die praxis: ace-hemmstoffe sind in der gesamten schwangerschaft kontraindiziert bzw. nur der therapie schwerer, nicht anders behandelbarer erkrankungen vorbehalten. da es keine hinweise auf ein nennenswertes teratogenes potenzial in der frühschwangerschaft gibt, rechtfertigt eine exposition im 1. trimenon keinen risikobegründeten schwangerschaftsabbruch (siehe kapitel 1.15). umgehend sollte aber auf eines der empfohlenen antihypertensiven mittel umgestellt werden. die fetale entwicklung sollte per ultraschallfeindiagnostik kontrolliert und bei längerfristiger therapie in der spätschwangerschaft ein oligohydramnion ausgeschlossen werden. beim neugeborenen muss auf die nierenfunktion und eine mögliche hypotonie geachtet werden, wenn im letzten drittel der schwangerschaft (versehentlich) mit ace-hemmstoffen behandelt wurde. g 2.8.7 angiotensin-ii-rezeptor-antagonisten zu den anderen peripheren § -rezeptorenblockern bunazosin (andante ® ), doxazosin (z. b. diblocin ® ), indoramin (wydora ® ), terazosin (z. b. heitrin ® ) und urapidil (z. b. ebrantil ® ) liegen ebenfalls keine ausreichenden erfahrungen zur abschätzung des embryotoxischen potenzials vor. urapidil, intravenös injiziert, wird allerdings von der deutschen sektion der "international society for the study of hypertension in pregnancy" als alternative zu dihydralazin bei der präeklampsiebehandlung empfohlen. es soll gegenüber dihydralazin den vorteil besitzen, dass der intrazerebrale druck nicht ansteigt. schulz (2001) kommt in einer klinischen vergleichsstudie zu dem ergebnis, dass urapidil eine gleichwertige antihypertensive alternative zu dihydralazin bei präeklampsie darstellt. guanabenz, guanethidin (z. z. nur in augentropfen thilodigon ® ), guanfacin und moxonidin (z. b. cynt ® ) gehören zur gruppe der zentral wirksamen § -rezeptoragonisten, zu denen eine fundierte risikobewertung mangels dokumentierter erfahrungen nicht möglich ist. minoxidil (z. b. lonolox ® ), ein vasodilatator, der in lokaler anwendung zur förderung des haarwuchses benutzt wird, kann einzelberichten zufolge eine hypertrichosis beim fetus verursachen, die sich aber in den ersten 3 lebensmonaten wieder verliert. einzelne fallberichte zu neugeborenen mit verschiedenen fehlbildungen lassen keine differenzierte risikobewertung zu. auch zu dem vasodilatator diisopropylamin liegen keine ausreichenden erfahrungen vor. gleiches gilt für cicletanin (justar ® ). phenoxybenzamin (dibenzyran ® ), ein § -adrenerger blocker, wird zur behandlung des phäochromozytoms und bei neurogenen blasenentleerungsstörungen eingesetzt. publizierte erfahrungen zur anwendung im 1. trimenon gibt es nicht. in den kasuistiken mit exposition in der späteren schwangerschaft wurden keine entwicklungsstörungen beschrieben. bosentan (tracleer ® ) ist ein endothelin-rezeptor-antagonist, der bei pulmonaler arterieller hypertonie zur verbesserung der körperlichen belastbarkeit eingesetzt wird. es gibt nur einen fallbericht zu einer kompliziert verlaufenden schwangerschaft mit versehentlicher einnahme von bosentan und sildenafil bis zur entbindung in schwangerschaftswoche 30. das wachstumsretardierte mädchen hatte keine fehlbildungen. nach anfänglich gutem gedeihen verstarb es im alter von 6 monaten an einer rs-virus-infektion (molelekwa 2005) . sildenafil (viagra ® ) wurde in einer experimentellen vergleichstudie an menschlichen plazenten getestet: 27 plazenten aus normalen schwangerschaften und 12 aus solchen mit fetaler wachstumshemmung wurden mit und ohne sildenafil untersucht. sildenafil verbesserte die plazentare durchblutung bei den plazenten, die aus schwan-gerschaften mit intrauteriner wachstumsverzögerung stammten (wareing 2005) . in den usa soll sildenafil für die indikation der pulmonalen hypertonie zugelassen werden. ein kürzlich publizierter fallbericht (siehe bosentan) hat keine fehlbildungen nach sildenafil beobachtet. der serotoninantagonist ketanserin wird unter anderem auch bei arterieller hypertonie eingesetzt. bisherige erfahrungen bei der behandlung der präeklampsie haben keine spezifischen fetotoxischen effekte gezeigt. nesiritide ist ein neuer wirkstoff zur behandlung der herzinsuffizienz. erfahrungen in der schwangerschaft gibt es nicht. empfehlungen für die praxis: urapidil kann in der spätschwangerschaft als alternative zu dihydralazin bei der präeklampsie eingesetzt werden. prazosin kommt im 2./3. trimenon nur bei versagen der primär empfohlenen antihypertensiva infrage. phenoxybenzamin kann beim phäochromozytom eingesetzt werden. die anderen genannten substanzen sind mangels ausreichender erfahrung in der schwangerschaft zu meiden. besser erprobte, in den vorangehenden abschnitten besprochene mittel sind vorzuziehen. eine dennoch erfolgte einnahme stellt keine indikation zum risikobegründeten schwangerschaftsabbruch oder zu invasiver diagnostik dar (siehe kapitel 1.15). g 2.8.13 hypotonie und antihypotonika eine hypotonie ist im prinzip ohne klinische bedeutung für den schwangerschaftsverlauf. sie sollte abgegrenzt werden von einer in der schwangerschaft nicht seltenen kreislaufdysregulation. bei deren therapie stehen physikalische maßnahmen, wie das tragen von kompressionsstrümpfen, beingymnastik vor dem aufstehen, kaltwasseranwendungen und bürstenmassage im vordergrund. auch kaffee ist in maßen erlaubt. eine medikamentöse therapie ist gewöhnlich nicht indiziert. in den 80er jahren wurde, überwiegend auf den deutschsprachigen raum begrenzt, den folgen einer chronischen hypotonie in der schwangerschaft besondere aufmerksamkeit gewidmet. eine bis auf 17 % erhöhte frühgeburtsrate schrieb man der unbehandelten hypotonie zu (goeschen 1984), und es wurde für eine medikamentöse behandlung plädiert. dabei wurde das wirkungsprofil (z. b. tonisierung auch des venösen systems) bei dihydroergotamin günstiger als bei den adrenergen substanzen beurteilt (goeschen 1984) . andere autoren widersprachen einer therapieempfehlung aus "fetaler" indikation (wolff 1990). in der englischsprachigen literatur finden sich zu diesem thema und zur risikobewertung der betreffenden arzneimittel praktisch keine publikationen, da man dort die hypotonie in der schwangerschaft nicht als therapiepflichtige erkrankung betrachtet. (oudijk 2002) . als zweite wahl, in kombination mit und ohne digitalis, kommen sotalol und/oder flecainid infrage (doherty 2003 , oudijk 2003 . bei flecainid dauert es ca. 72 stunden (maximal 14 tage), bis der umschlag in einen sinusrhythmus zu erwarten ist (krapp 2002) . einige autoren diskutieren verapamil als zweite therapieoption (athanssiadis 2004), andere halten es für kontraindiziert (oudijk 2002) . falls diese medikamente nicht zum sinusrhythmus führen, kann adenosin direkt in die vena umbilicalis appliziert werden. es gibt beispiele dafür, dass der hydrops sich allmählich nach erfolgreicher kardioversion zurückbildet (d' souza 2002), das kann 8 tage (porat 2003) oder auch 4-6 wochen dauern. berichtet wird auch über einen fetus mit einem hydrops als folge einer tachykarden rhythmusstörung, der über die mutter mit flecainid behandelt wurde. ein sinusrhythmus stellte sich dennoch nicht ein. es kam lediglich zur abnahme der herzfrequenz, die aber ausreichte, um zu einer rückbildung des hydrops zu führen (krapp 2002) . bei nicht erfolgreicher therapie wird ggf. auch über eine vorzeitige entbindung diskutiert, um z. b. postnatal elektrisch kardiovertieren zu können. im allgemeinen wird eine antiarrhythmische therapie bei herzgesunden schwangeren gut vertragen. als fetale nebenwirkung kann es selten zur bradykardie kommen, die bei direkter adenosinapplikation in die nabelvene wahrscheinlicher ist als bei einer diaplazentaren therapie. nicht auszuschließen ist auch ein arrhythmogener effekt des antiarrhytmikums, der zum kammerflimmern beim fetus und zum intrauterinen fruchttod führen kann. eine fetale bradykardie kann zunächst durch ein kompensatorisch größeres schlagvolumen ausgeglichen werden. eine fetale herzfrequenz von 55/minute wird als hämodynamisch nicht mehr ausreichend beschrieben (eronen 2001). daraus kann sich eine herzinsuffizienz entwickeln, die bis zum hydrops führen kann. die ursache ist meist ein av-block iii°, der durch diaplazentare autoantikörper der mutter (meist anti-ro-antikörper) verursacht wird. als therapieoption kommen die gabe von halogenierten steroiden (solange der av-block noch nicht komplett ist) oder ggf. eine vorzeitige entbindung infrage, um postnatal einen schrittmacher implantieren zu können. auch sympathomimetika wurden versuchsweise eingesetzt. (tambocor ® ) und propafenon (z. b. rytmonorm ® ) sowie encainid und lorcainid. 7 die klasse-ii-antiarrhythmika umfassen die g -rezeptorenblocker. 7 zu den klasse-iii-antiarrhythmika gehören amiodaron (corda. das nukleosid adenosin wird keiner der klassischen antiarrhythmikagruppen zugeordnet. klasse-ia-antiarrhythmika: chinidin wird nach oraler zufuhr fast vollständig resorbiert und erreicht in 1-4 stunden seine maximale serumkonzentration. etwa 20 % werden über die nieren, 80 % über die leber ausgeschieden. als vagusantagonist kann es trotz depressorischer wirkung auf die schrittmacherzellen die herzfrequenz leicht erhöhen. chinidin als eines der ältesten antiarrhythmika hat offenbar kein nennenswertes teratogenes potenzial. es ist plazentagängig und erreicht beim fetus ähnlich hohe konzentrationen wie bei der mutter. sowohl bei schwangeren als auch bei feten wurde es erfolgreich eingesetzt. der beschriebene wehenfördernde effekt des chinidins ist bei antiarrhythmischer dosierung nicht zu erwarten. auch disopyramid soll eine wehenfördernde wirkung besitzen . fallberichte in zusammenhang mit fehlbildungen nach disopyramid oder procainamid wurden bisher nicht publiziert. beide substanzen sind plazentagängig. procainamid wurde auch erfolgreich bei fetaler tachykardie eingesetzt. zu ajmalin, detajmium und prajmalium liegen keine ausreichenden erfahrungen zur pränatalen verträglichkeit vor. klasse-ib-antiarrhythmika: die meisten der umfangreichen erfahrungen mit lidocain in der schwangerschaft liegen zur anästhetischen anwendung vor. zur antiarrhythmischen behandlung wird es parenteral appliziert, da es oral nicht ausreichend wirkt. cuneo (2003) beschreibt einen fetus mit qt-verlängerung im ekg, der ventrikuläre tachykardien und einen intermittierenden av-block ii°hatte und erfolgreich mit lidocain therapiert wurde. ein teratogener effekt beim menschen ist nicht beschrieben. lidocain ist gut plazentagängig und kann bei hohen konzentrationen beim neugeborenen zur zns-depression führen, zur anwendung unter der geburt siehe kapitel 2.16.6. über eine völlig andere indikation wird in einer studie aus frankreich berichtet: die anwendung von lidocain zur herbeiführung des fetozids in 50 fällen. feten (zwischen schwangerschaftswoche 20 und 36) mit verschiedenen fehlbildungen erhielten über die nabelvene zunächst sufentanil (5 ? g), dann 7 bis 30 ml lidocain (1%) und erlitten dadurch eine kardiale asystolie (senat 2003) . phenytoin ist ein teratogenes antikonvulsivum (siehe abschnitt 2.10.12). mexiletin ist plazentagängig und hat sich in wenigen fallberichten bisher als nicht bedenklich erwiesen. zu aprindin und tocainid gibt es keine für eine bewertung ausreichenden erfahrungen. klasse-ic-antiarrhythmika: eine vielzahl an fallberichten beschreibt die gute wirksamkeit von flecainid bei der behandlung von fetalen tachykardien (krapp 2002) . besonders bei feten, die schon einen hydrops entwickelt haben, ist es digitalisglykosiden überlegen. eine engmaschige kontrolle der mütterlichen serumkonzentration als hinweis auf die fetale konzentration wird empfohlen (rasheed 2003) , damit nebenwirkungen minimiert werden können. in einer kasuistik ist eine hyperbilirubinämie beim neugeborenen als nebenwirkung beschrieben (nach athanassiadis 2004) . bisher ist im gegensatz zu tierexperimentellen erfahrungen kein teratogener oder fetotoxischer effekt beim menschen erkennbar; allerdings gibt es kaum fallberichte zur anwendung im 1. trimenon. propafenon ist bisher unzureichend in der schwangerschaft untersucht. der hersteller berichtet über mehr als 30 schwangerschaften unter propafenon, aus denen kein nennenswertes vorgeburtliches risiko abgeleitet werden kann. in unserer datenbank gibt es 7 im 1. trimenon exponierte schwangerschaften, darunter einen spontanabort und zwei abbrüche wegen der mütterlichen erkrankung. die 4 lebend geborenen kinder waren gesund. klasse-ii-antiarrhythmika: zu g -rezeptorenblockern siehe abschnitt 2.8.2. klasse-iii-antiarrhythmika: amiodaron hat eine sehr lange eliminationshalbwertszeit von 14-58 tagen. wenn eine fetale exposition vermieden werden soll, müsste das medikament einige monate vor der konzeption abgesetzt werden. folgende fetale nebenwirkungen sind gehäuft aufgetreten: fetale bradykardien sowie konnatale hypothyreosen, ausgelöst durch den jodanteil von 39 % (lomenick 2004 , grosso 1998 (magee 1999) . die erfahrungen mit amiodaron im 1. trimenon sind auf etwa 20 exponierte schwangerschaften, die im wesentlichen unauffällig waren, begrenzt . sotalol ist aufgrund seines guten plazentaren übergangs ein potentes antiarrhythmikum, das zur behandlung von fetalen tachykardien infrage kommt. in einer fallserie von 18 feten mit tachykardie wurde eine akkumulation im fruchtwasser, nicht aber im fetus selbst festgestellt. von den 14 feten, die sotalol als monotherapie erhielten, konnte bei 13 ein sinusrhythmus wiederhergestellt werden, zwei wurden rückfällig, in einem fall kam es zum intrauterinen fruchttod. bei zwei der vier feten, die zusätzlich digoxin erhielten, war die behandlung erfolgreich (oudijk 2003 (danielsson 2001) . klasse-iv-antiarrhythmika: zu den bereits seit längerem eingeführten calciumantagonisten verapamil und diltiazem siehe abschnitt 2.8.5. tierexperimentelle ergebnisse zeigten zwar teratogene entwicklungsstörungen, z. b. im bereich der distalen phalangen, die bisherigen erfahrungen beim menschen erbrachten aber keine entsprechenden hinweise. adenosin hat eine sehr kurze halbwertszeit von weniger als 2 sekunden und muss i.v. injiziert werden. die bisherigen erfahrungen bei schwangeren und mit der behandlung fetaler arrhythmien ergaben keine fetotoxischen effekte (hubinont 1998). das gleiche gilt für die elektrokardioversion einschließlich der implantierten defibrillatoren. die reizschwelle beim fetalen herzen liegt relativ hoch, außerdem befindet sich der fetus außerhalb des direkten spannungsfeldes bzw. stromflusses (joglar 1999). empfehlung für die praxis: da antiarrhythmika selbst arrhythmien verursachen können, ist die indikation einer behandlung kritisch zu prüfen. mittel der wahl für die therapie der schwangeren sind in der gruppe ia chinidin, in ib lidocain, in ic kommen sowohl propafenon als auch im 2. und 3. trimenon flecainid infrage. in gruppe ii sollten lang eingeführte g -rezeptorenblocker bevorzugt werden. ist ein klasse-iii-antiarrhythmikum erforderlich, sollte sotalol gewählt werden. in der gruppe iv sind verapamil und diltiazem akzeptabel. wegen erwiesener teratogenität ist phenytoin kontraindiziert. wurde mit einem der primär nicht empfohlenen mittel behandelt oder sind diese aus mütterlicher oder fetaler indikation zwingend erforderlich, rechtfertigt dies keinen risikobegründeten abbruch der schwangerschaft. abgesehen von gut untersuchten g -rezeptorenblockern und calciumantagonisten sollte bei einer exposition im 1. benzothiadiazide werden gut im magen-darm-trakt resorbiert und unverändert mit dem urin ausgeschieden. sie passieren die plazenta und können, sub partu gegeben, zu elektrolytveränderungen (hyponatriämie, hypokaliämie), zu thrombozytopenie und reaktiver hypoglykämie (infolge eines diabetogenen effekts auf die mutter) beim neugeborenen führen. außerdem wurde eine geburtsverzögerung durch die hemmende wirkung auf die glatte muskulatur beschrieben. bei patientinnen mit schwerer präeklampsie ist das intravasale volumen in den meisten fällen vermindert; benzothiadiazidderivate würden es noch zusätzlich reduzieren (sibai 1985) . außerdem wurde eine herabsetzung der plazentaperfusion beobachtet, die über eine beeinträchtigung der fetalen versorgung zu vermindertem intrauterinen wachstum führt. klinisch gibt es bisher keinen anhalt für teratogene wirkungen dieser saluretika, dies haben publizierte erfahrungen an insgesamt über 5.000 behandelten schwangeren ergeben. am besten untersucht ist hydrochlorothiazid. in einer gruppe von 567 im 1. trimenon behandelten schwangeren wurde weder eine häufung spezieller anomalien noch eine erhöhte gesamtfehlbildungsrate gefunden (übersicht in . auch bei 46 neugeborenen mit indapamid-exposition im 1. trimenon waren weder häufigkeit noch art der anomalien auffällig (übersicht in . anhand dänischer und schottischer register wurden 315 bzw. 73 schwangerschaften analysiert, in denen mindestens einmal diuretika verschrieben worden waren (olesen 2001 . insbesondere bei kombination mit aminoglykosiden wird eine ototoxische wirkung beschrieben (brown 1991 , salamy 1989 . in zwei fallberichten wurden nach behandlung mit etacrynsäure im 3. trimenon eine schädigung des innenohres (jones 1973) und störungen des säure-basen-haushaltes (fort 1971) beschrieben. bisher gibt es keine anderen substantiellen hinweise auf teratogene schäden beim menschen. der umfang an dokumentierten erfahrungen ist jedoch unzureichend für eine differenzierte risikobewertung. nach therapie mit bumetanid im 1. trimenon wurden in einer gruppe von 44 schwangeren zwei kinder mit fehlbildungen des herzens geboren (zitiert in . zu den anderen schleifendiuretika azosemid, etozolin, piretanid und torasemid, liegen keine erfahrungen in ausreichendem umfang vor. eine spezifische teratogene wirkung ist bisher bei keinem der genannten mittel zu erkennen. anhand dänischer und schottischer register wurden 315 bzw. 73 schwangerschaften analysiert, in denen mindestens einmal diuretika verschrieben worden waren (olesen 2001 bar 2000 , sørensen 2000 , chan 1999 , sanson 1999 , schneider 1997 , dulitzki 1996 . eher anekdotischen charakter hat ein fallbericht zur aplasia cutis bei tinzaparin-therapie ab woche 10 (sharif 2005). daher können im bedarfsfall die vorzüge niedermolekularer heparine auch in der schwangerschaft genutzt werden, so beispielsweise bei schwerer, früh manifester präeklampsie, abortneigung und intrauteriner wachstumsretardierung infolge erworbener oder angeborener thrombophilie ( bar 2000 , kupferminc 1999 ). obwohl niedermolekulare heparine die menschliche plazenta nicht oder kaum überwinden (greer 1999 , sanson 1999 , wurden im tierexperiment dennoch auswirkungen auf die fetale gerinnung beobachtet. (hall 1980) . besonders gefürchtet sind größere zerebrale blutungen in der spätschwangerschaft und unter der geburt. die cumarinembryopathie ähnelt der chondrodysplasia punctata conradi-hünermann (savarirayan 1999 , becker 1975 . im zusammenhang mit diesem krankheitsbild wurde die ätiologisch relevante mutation der arylsulfatase e (arse) beschrieben, die zum (völligen) aktivitätsverlust dieses enzyms führt. die cumarinembryopathie als identischer phänotyp wird mit einer cumarinbedingten arse-hemmung in zusammenhang gebracht (savarirayan 1999). (schaefer 2006) . in dieser, von uns durchgeführten, multizentrischen studie wurden 226 schwangere mit acenocoumarol therapiert, 280 mit phenprocoumon, 99 mit fluindion, 2 mit phenindion und 63 mit warfarin. vier der patientinnen erhielten 2 vitamin-k-antagonisten. im vergleich zu einer nichtbehandelten kontrollgruppe fand sich ein mit 4,9% vs. 1,4 % (or 3,86) signifikant erhöhtes risiko für große fehlbildungen nach exposition im 1.trimenon. die beobachteten fehlbildungen waren jedoch heterogen, nur zwei cumarinembryopathien unter insgesamt 356 lebendgeborenen wurden beobachtet (0,6 %). andere auswirkungen einer cumarintherapie. weitere ergebnisse der multizentrischen kohortenstudie (schaefer 2006 ) sind ein geringeres geburtsgewicht, das nur zum teil durch die erhöhte frühgeburtenrate erklärt wurde. spontanaborte traten 3-mal häufiger unter cumarintherapie auf, am höchsten war die rate bei phenprocoumon mit 42% gegenüber 14 % in der kontrollgruppe. natürlich kann auch die grunderkrankung der mütter, wie herzklappendefekte, embolien, verschiedene koagulopathien, zum ungünstigeren abschneiden der cumaringruppe beigetragen haben. die mütterliche erkrankung war in einigen fällen auch der grund für den medizinisch indizierten schwangerschaftsabbruch. ein problem stellen die undifferenzierten, das teratogene risiko übertreibenden warnhinweise auf packungsbeilagen dar, die häufig zu einer erheblichen verunsicherung von patientinnen und ärzten führen. sensible phase. weder in den früher publizierten fallberichten noch bei den von uns beobachteten, ausschließlich vor schwangerschaftswoche 9 exponierten 235 lebendgeborenen ergeben sich hinweise darauf, dass bis schwangerschaftswoche 8 p.m. ein nennenswertes risiko für eine cumarinembryopathie besteht. es wird gelegentlich von einer sensiblen phase in den wochen 6 bis 9 gesprochen. eine kritische analyse derjenigen fallberichte, die als beleg für ein embryopathierisiko vor woche 9 p.m. interpretiert werden könnten (hall 1989 , balde 1988 , ruthnum 1987 , lapiedra 1986 , cox 1977 , lässt zweifel an der richtigkeit dieser hypothese aufkommen. es ist zumindest nicht eindeutig, dass in diesen fallberichten ausschließlich vor woche 9 p.m. behandelt wurde, dass es sich um cumarinspezifische anomalien handelte und dass nicht weitere teratogene faktoren im spiel waren. die zwei in unserer studie erfassten typischen embryopathien ereigneten sich bei schwangeren, die deutlich länger als bis woche 8 bzw. ausschließlich danach behandelt wurden. andererseits könnte das erhöhte spontanabortrisiko ergebnis einer embryotoxischen schädigung sein. es kann aber auch ebenso wie die erhöhte rate an frühgeburten, folge der grunderkrankung sein. mentale entwicklung. die spätere entwicklung im alter von 7 bis 15 jahren wurde in einer studie an etwa 300 kindern mit pränataler cumarinexposition untersucht (van driel 2001 , wesseling 2000 . nur zwei kinder in dieser gruppe wiesen bei der geburt typische zeichen einer cumarinembryopathie auf. diese waren im alter von 9 bzw. 13 jahren normal entwickelt (van driel 2002) . die durchschnittliche größe der exponierten kinder unterschied sich nicht von einer kontrollgruppe. keines der exponierten kinder war hinsichtlich seiner neurologischen entwicklung deutlich auffällig. lediglich leichte neurologische abweichungen traten etwas häufiger auf, wenn die mutter im 2. oder 3. trimenon behandelt wurde. der durchschnittliche iq unterschied sich nicht signifikant von der kontrollgruppe. allerdings wurden in der cumaringruppe mit 11 gegenüber 3 mehr kinder mit einem iq x 80 gezählt. diese kinder wiesen keine typischen dysmorphiezeichen auf. auch hinsichtlich der verhaltensentwicklung gab es keine häufung von problematischen entwicklungen, allenfalls leichte differenzen bei einzelnen tests. drei andere studien mit insgesamt 72 kindern fanden ebenfalls keine signifikanten unterschiede hinsichtlich körperlicher und mentaler entwicklung (olthof 1994 , wong 1993 , chong 1984 die diagnose der dysmorphiezeichen ist nicht immer einfach, sie unterliegt subjektiven bewertungsunterschieden und ist z. t. nur radiologisch nachweisbar (harvey 2003 , lu 2000 . gewöhnlich treten nur einige und nicht alle beschriebenen fehlbildungen bzw. dysmorphien auf. g 2. funktionsstörungen des zns kommen häufiger bei kindern mit mittelgesichtshypoplasie vor; die angaben bewegen sich im zweistelligen prozentbereich. moore und mitarbeiter (2000) untersuchten 57 kinder mit einem antiepileptika-syndrom und fanden bei etwa 80 % verhaltensauffälligkeiten, sprachentwicklungsstörungen, lernstörungen und bei 60 % zwei oder mehr autistische symptome. im vergleich der verschiedenen antiepileptika finden sich diese entwicklungsauffälligkeiten vor allem nach vorgeburtlicher exposition mit valproinsäure (übersicht in schmitz 2006 , adab 2001 . g 2.10.5 wie spezifisch wirken die einzelnen antiepileptika? eine spezifische zuordnung von fehlbildungsmustern zu den einzelnen antiepileptika ist, abgesehen von einigen ausnahmen, nicht möglich (morrow 2003 (2000) haben 57 kinder untersucht, deren mütter eine epilepsie in der vorgeschichte angaben und die während der schwangerschaft weder unter krampfanfällen litten noch antiepileptisch behandelt wurden. diese kinder zeigten gegenüber einer kontrollgruppe weder einschränkungen der intelligenzentwicklung noch die nach antikonvulsiver behandlung in der schwangerschaft gehäuft beschriebenen dysmorphien des gesichts oder der finger. adab und mitarbeiter (2004) stellten hingegen einen niedrigen sprach-iq ( x 79) signifikant häufiger fest, wenn während der schwangerschaft -unabhängig von einer antikonvulsiven therapiemehr als 5 generalisiert tonisch-klonische anfälle auftraten. g 2.10.8 folsäure und antiepileptika eine substitution mit folsäure bei therapie mit folsäure-antagonistischen antiepileptika in der schwangerschaft wird verschiedentlich empfohlen, der nachweis protektiver wirksamkeit wurde bisher jedoch nicht erbracht (hernandezdiaz 2000) . da heute generell für alle frauen mindestens bis schwangerschaftswoche 9 eine folsäureprophylaxe empfohlen wird (siehe kapitel 2.18 vitamine), sollten selbstverständlich auch an epilepsie erkrankte frauen mit kinderwunsch eine folsäuresubstitution durchführen, und zwar mit einer dosis von 5 mg/ tag, wie sie auch zur minderung des wiederholungsrisikos von neuralrohrdefekten empfohlen wird. dabei ist zu beachten, dass folsäure den arzneimittelmetabolismus der hydroxylasen in der leber anregt, so dass die konzentrationen von antiepileptika im blut der mutter erniedrigt sein können. g 2.10.9 vitamin k und antiepileptika unabhängig von einer medikation der mutter weisen neugeborene und insbesondere frühgeborene einen vitamin-k-mangel auf, der zur verhütung von blutungskomplikationen unmittelbar nach geburt durch substitution behoben werden muss. darüber hinaus gehören carbamazepin, ethosuximid, oxcarbazepin, phenytoin, phenobarbital, topiramat, vigabatrin und zonisamid zu den enzym induzierenden arzneimitteln, die eine verminderung der vitamin-k-abhängigen gerinnungsfaktoren induzieren können. als indirekter marker kann die prothrombinvorstufe pivka ii (protein induced by vitamin k abscence of factor ii) beim neugeborenen erhöht sein. es wurde vielfach empfohlen, dass bei einer therapie mit vitamin-kantagonisierenden medikamenten die mutter in den letzten vier schwangerschaftswochen täglich vitamin k 1 (z. b. konakion ® ) einnimmt, zunächst 10 mg am tag und während der letzten beiden wochen 20 mg. die wirksamkeit dieses vorgehens ist umstritten (hey 1999). kaaja und mitarbeiter (2002) vitamin k wird zwar oral ähnlich gut aufgenommen wie parenteral, aber unmittelbar nach der geburt kann diese verabreichungsform aufgrund der situation im kreissaal unzuverlässig sein, so dass eine intramuskuläre applikation von 0,5-1 mg vitamin k 1 zu empfehlen ist. diese soll vor allem zur prävention von spätblutungen (ab 2 wochen) der oralen verabreichung überlegen sein (american academy of pediatrics 2003). wird die orale prophylaxe gewählt, ist gewissenhaft darauf zu achten, dass das neugeborene die dosis auch tatsächlich herunterschluckt und in den ersten beiden wochen alle 3 tage eine zusätzliche orale dosis erhält. g 2.10.10 die neueren antiepileptika zu den neueren antiepileptika zählen felbamat, gabapentin, lamotrigin, levetiracetam, oxcarbazepin, pregabalin, tiagabin, topiramat, vigabatrin, zonisamid. sie wurden in den 90er jahren zunächst als so genannte add-on-antiepileptika eingeführt als zusatz zu klassischen antiepileptika bei fokalen epilepsien. die proteinbindung ist bei den neuen antiepileptika meist niedriger als bei den klassischen antiepileptika: felbamat 30 %, gabapentin 0 %, lamotrigin 55 %, oxcarbazepin 40 %, tiagabin 96%, topiramat 15 %, vigabatrin 0 %, zonisamid 40-50 %. die neuen antiepileptika induzieren das cytochrom-p450-enzymsystem gar nicht oder, wie oxcarbazepin und topiramat, in geringerem umfang und sie bilden keine potenziell teratogenen arenoxid-bzw. epoxidmetaboliten (bruno 2002) . im gegensatz zu den klassischen antiepileptika besitzen sie keine nennenswerte antifolatwirkung und zeigen eine geringere interaktion mit sexualhormonen. tierexperimentell haben felbamat, gabapentin und lamotrigin bisher keine hinweise auf teratogenität erbracht, während alle klassischen antiepileptika im tierversuch teratogen wirken. die mit ausnahme von lamotrigin noch recht spärlich vorliegenden klinischen verlaufsbeobachtungen zur schwangerschaft deuten bei monotherapie nicht auf eine spezifische teratogenität hin. möglicherweise ist das teratogene risiko dieser gruppe bei monotherapie geringer als bei den klassischen antiepileptika. eine abschließende beurteilung der neuen antiepileptika ist jedoch noch nicht möglich. typische fehlbildungen. carbamazepin wirkt wie die anderen klassischen antiepileptika nicht nur im tierversuch, sondern auch beim menschen teratogen. ein spezifisches carbamazepin-syndrom wurde ende der 80er-jahre postuliert, das epikanthus, antimongoloide lidachse, kurze nase, langes philtrum, hypoplasie der endphalangen, mikrozephalie und entwicklungsretardierung umfasste (jones 1989) . andere untersucher konnten die spezifität dieser auffälligkeiten nicht bestätigen oder fanden keine häufung von hypoplasien der distalen phalangen. fehlbildungen, die im zusammenhang mit carbamazepin vermehrt beschrieben wurden, betreffen herz und extremitäten, hüftanomalien, inguinalhernien, gaumenspalten und hypospadien (ornoy 1996 toxikologie. es gibt nur wenige berichte über die therapie mit ethosuximid in der schwangerschaft. typische fehlbildungsmuster wurden bei den kindern von 57 behandelten frauen nicht beobachtet (lindhout 1992) . eine andere fallsammlung mit 18 im 1. trimenon exponierten schwangeren ergab keinen anhalt für fehlbildungen (rosa, zitiert in briggs 2005) . auch wenn die vorliegenden berichte für eine differenzierte risikobewertung nicht ausreichen, scheint kein erhebliches teratogenes potenzial vorzuliegen. über eine erhöhte neonatale blutungsbereitschaft durch einen vitamin-k-antagonismus wurde berichtet (siehe kapitel 2.10.9). zu den anderen succinimiden mesuximid (petinutin ® ) und phensuccimid liegen keine für eine beurteilung ausreichenden erfahrungen vor. (janz 1964) und gilt als erwiesen, auch wenn dies nicht in allen studien bestätigt werden konnte (samrén 1999). im vordergrund stehen herzfehlbildungen, lippen-kiefer-gaumen-spalten und urogenitale fehlbildungen. ursprünglich wurden diese anomalien als "fetales hydantoin-syndrom" bezeichnet (siehe kapitel 2.10.3 und 2.10.5). häufigkeit großer fehlbildungen. kaaja und mitarbeiter (2003) einschränkungen der kognitiven entwicklung wurden unter phenytointherapie gehäuft beobachtet (scolnik 1994 , vanoverloop 1992 , hättig 1987 . eine gesichtsdysmorphie kann auf ein erhöhtes risiko mentaler entwicklungseinschränkungen hinweisen (orup 2000) . koch und mitarbeiter (1999) vpa wird nach oraler gabe gut resorbiert und liegt im plasma zu 95 % an eiweiß gebunden vor. die lipophilie erklärt, dass vpa die blut-hirn-schranke und die plazenta leicht überwindet. gegen ende der schwangerschaft wird vpa in stärkerem umfang in der leber metabolisiert, gleichzeitig nimmt der ungebundene anteil im plasma zu. beide effekte können sich aufheben, so dass die verfügbare aktive substanz in etwa gleich bleibt (nau 1981) . die konzentration im nabelvenenblut ist bei geburt mit dem 1,4-2,4fachen deutlich höher als im mütterlichen plasma (nau 1981) . neugeborene scheiden vpa aufgrund der noch nicht ausgereiften leberenzyme verzögert aus. die halbwertszeit kann von 8-15 auf 15-60 stunden verlängert sein. vpa verstärkt möglicherweise zyklusunregelmäßigkeiten und wird im zusammenhang mit dem polycystischen ovar-syndrom (pcos) diskutiert, das mit einer herabgesetzten fertilität und einem erhöhtem testosteronspiegel einhergeht (isojärvi 1993) . eine nennenswerte beeinträchtigung oraler kontrazeptiva durch enzyminduktion ist nicht bekannt. typische fehlbildungen. ein valproinsäure-syndrom wurde in den 80er jahren definiert, das dysmorphe entwicklungen an augenlidern, nase und mund umfasste, wie z. b. epikanthus, flache nasenwurzel, flaches philtrum sowie schmale sich überkreuzende finger und zehen und hyperkonvexe nägel (kozma 2001) . außerdem wurde über eine als trigonozephalie imponierende auffälligkeit der schädelform berichtet. weitere fallberichte beschreiben verschiedene präaxiale extremitätenanomalien (rodriguez-pinella 2000 , sharony 1993 , robert 1992 speziell für fehlende oder hypoplastische extremitätenanlagen errechneten rodriguez-pinella und mitarbeiter (2000) gegenüber einer kontrollgruppe ein etwa 6fach erhöhtes risiko, danach sind 0,4 % der exponierten kinder von einer derartigen entwicklungsstörung betroffen. dosis-wirkungs-beziehung. einige studien untersuchten für vpa die dosisabhängigkeit des fehlbildungsrisikos. mehr als 1.000 mg/tag oder eine serumkonzentration über 70 ? g/ml ergab ein signifikant höheres risiko (kaneko 1999 , samrén 1997 . morrow und mitarbeiter (2006) (kaaja 2003) . andere organanomalien. dean und mitarbeiter (2002) verglichen 149 pränatal exponierte kinder mit 38 (älteren) geschwistern, bei denen die mütter keine antiepileptika in der schwangerschaft genommen hatten. bei monotherapie mit vpa ergab sich ein signifikant höheres risiko für gesichtsdysmorphien (70 % versus 25 %). erkrankungen in der späteren kindheit (sehstörungen, otitis media, gelenkprobleme) wurden ebenfalls häufiger beobachtet. die ergebnisse dieser studie sind aufgrund der kleinen fallzahlen vorsichtig zu bewerten, bemerkenswert ist der hohe anteil auffälliger kinder bei den pränatal exponierten und den kontrollen. die autoren einer anderen studie warnen von der überbewertung der zeichen einer gesichtsdysmorphie (kini 2006) . sie fanden auffälligkeiten am häufigsten bei vpa, allerdings wiesen auch 45 % der kinder nicht behandelter, an epilepsie erkrankter mütter einige der dysmorphiezeichen auf. neonatale auffälligkeiten. zu weiteren auffälligkeiten der therapie mit vpa gehören fetale hypoxie mit niedrigen apgar-werten, mikrozephalie und ein vermindertes postnatales wachstum. auch leberzellnekrosen wurden bei einzelnen kindern nach vpa-behandlung der mutter beschrieben (legius 1987) , ebenso hämorrhagien infolge von fibrinogenmangel und gestörter thrombozytenfunktion (bavoux 1994) und eine hypoglykämie des neugeborenen (ebbesen 1998). mentale entwicklungsauffälligkeiten. koch und mitarbeiter (1996) zeigten, dass übererregbarkeit und andere neurologische auffälligkeiten im verlauf der kindheit mit der vpa-konzentration im nabelschnurblut bei geburt korrelieren. eine beeinträchtigung der kognitiven entwicklung wird von einigen autoren diskutiert (ornoy 1996) in einer untersuchung an 57 kindern mit antiepileptika-syndrom -46 waren vpa-exponiert -zeigten 80 % der kinder sprachentwicklungsstörungen, lernstörungen und verhaltensauffälligkeiten. bei 60 % fanden sich mindestens 2 autistische symptome, bei 4 kindern wurde regelrecht die diagnose autismus gestellt, bei zweien ein asperger syndrom diagnostiziert (moore 2000) . eine andere untersuchung an 40 kindern, deren mütter mit einem antikonvulsivum (mono)therapiert wurden, fand man bei einer nachuntersuchung die stärksten auffälligkeiten in der vpa-gruppe. gaily und mitarbeiter (2004) (morrow 2006) . unter 15 prospektiv (monotherapie) und 9 retrospektiv von uns dokumentierten schwangerschaften sahen wir keine große fehlbildung. chambers und mitarbeiter (2005) neurotransmitter, antikonvulsiv wirkt und bei fokaler epilepsie verwendet wird. von 22 in einer publikation erwähnten schwangerschaften wurden 9 ausgetragen. darunter befand sich ein kind mit hüftluxation bei steißlage (leppik 1999 2000) . langzeitwirkungen psychotroper substanzen in der schwangerschaft sind bis auf wenige ausnahmen kaum untersucht, z. b. bei einigen antidepressiva (mattson 2004 , casper 2003 , nulman 2002 , klassischen antiepileptika und bei harten drogen (details siehe bei den entsprechenden substanzen). besonders psychopharmaka könnte man unterstellen, dass sie das fetale und kindliche zns in seiner funktionellen entwicklung stören und zu verhaltensauffälligkeiten, feinmotorischen störungen oder intellektuellen defiziten führen. (steyn 1998 , bolte 1997 . trizyklische antidepressiva treten aufgrund ihrer hohen lipidlöslichkeit rasch diaplazentar über. in manchen tierspezies erwiesen sich trizyklische antidepressiva als teratogen. in den 70er und 80er jahren wurden den klassischen antidepressiva auch beim menschen fehlbildungen zugeordnet, darunter extremitätenfehlbildungen, herzfehler, polydaktylie und hypospadie. jedoch konnte bei keinem der seit längerem gebräuchlichen präparate der verdacht auf teratogene effekte bestätigt werden (mcelhatton entis studie pers. mitteilung 2005 , ericson 1999 , mcelhatton 1996 , brunel 1994 , patuszak 1993 . speziell zu dosulepin, doxepin, lofepramin, opipramol und trimipramin liegen keine für eine fundierte risikobewertung ausreichenden fallzahlen zur anwendung in der schwangerschaft vor. allerdings ist auch bei diesen schon lange eingeführten mitteln nicht mit einem nennenswerten teratogenen risiko beim menschen zu rechnen. nach lang andauernder intrauteriner exposition (bis zur geburt) wurden bei neugeborenen entzugssymptome wie zittrigkeit, übererregbarkeit, atemnotsyndrom und vereinzelt auch krämpfe beobachtet a, bromiker 1994 , schimmel 1991 . sieht im gegensatz zu anderen untersuchern ein höheres risiko für neonatale anpassungsstörungen bei trizyklischen antidepressiva als bei den selektiven serotonin-wiederaufnahme-hemmstoffen (ssri). er hat in seiner studie mit annähernd 1.000 schwangeren in der trizyklika-gruppe vor allem clomipramin (n = 353) untersucht. diese und andere studien (ericson 1999) haben auch ein etwas höheres geburtsgewicht nach trizyklika-exposition beobachtet als bei den ssri. dieses phänomen wird mit einem diabetogenen effekt und intrauteriner hyperglykämie erklärt. bei 80 kindern, die vorwiegend im 1. trimenon mit trizyklika exponiert waren, zeigten sich im vorschulalter gegenüber einer kontrollgruppe keine abweichungen bei intelligenzentwicklung, verhalten und sprachentwicklung (nulman 1997) . eine spätere prospektive untersuchung derselben autorengruppe findet auch bei jenen kindern, deren mütter während der gesamten schwangerschaft trizyklika (46 mutter-kind-paare; davon 36 bereits in der studie von 1997 erfasst) genommen hatten, keine arzneispezifischen auffälligkeiten in der entwicklung der kinder im alter zwischen 15 und 71 monaten. die dauer der depression hatte jedoch auswirkungen auf den intelligenzquotienten und die häufigkeit depressiver episoden auf die sprachentwicklung. die autoren leiten daraus die notwendigkeit einer therapie bei schwangeren ab (nulman 2002) . empfehlung für die praxis: trizyklische antidepressiva gehören immer noch zu den mitteln der wahl bei therapiebedürftiger depression in der schwangerschaft. eine monotherapie ist anzustreben, gut dokumentierte präparate wie amitriptylin, clomipramin, desipramin, imipramin und nortriptylin sind zu bevorzugen. die anderen der o. g. antidepressiva sind aufgrund der geringeren erprobung reservemittel in der schwangerschaft. eine unter therapie stabile patientin sollte während einer schwangerschaft diese medikation unverändert fortsetzen, um keine für mutter und kind bedrohlichen krisen zu provozieren. zur dosisanpassung sollten die mütterlichen serumkonzentrationen während der schwangerschaft und nach entbindung untersucht werden. die anwendung unzureichend erprobter substanzen rechtfertigt weder einen risikobegründeten schwangerschaftsabbruch (siehe kapitel 1.15) noch invasive diagnostik. entzugssymptome beim neugeborenen sind möglich. deshalb sollte in den ersten beiden lebenstagen auf symptome beim kind geachtet werden. reaktive depressionen oder angstzustände sind nicht zwangsläufig eine indikation für die behandlung mit antidepressiva; auch psychotherapeutische optionen sollten ausgeschöpft werden. unter den ssri geht citalopram am stärksten plazentar über, gefolgt von fluoxetin. den geringsten übergang fand man bei sertralin, gefolgt von paroxetin (hendrick 2003) . es ist bekannt, dass serotonin schon während der embryogenese, also bevor es als neurotransmitter funktioniert, an der regulation der zellmigration, des axonwachstums und der anlage der synaptischen kommunikation beteiligt ist. tierexperimentelle ergebnisse zeigen, dass erhöhte serotoninspiegel neuroanatomische abweichungen verursachen mit verringerter anzahl von betaadrenergen-und serotoninrezeptoren sowie abnormer serotoninrezeptorbindung im zentralnervensystem (zns). bei mehreren tausend schwangerschaften unter ssri-behandlung im 1. trimenon sind teratogene effekte i.s. großer fehlbildungen beim menschen bislang nicht eindeutig nachzuweisen , auch wenn einige neuere publikationen vor allem bei paroxetin ein etwas höheres risiko für herzfehlbildungen diskutieren (siehe dort). bei behandlung mit ssri am ende der schwangerschaft fanden chambers und mitarbeiter (2006) cohen 2000 , chambers 1996 ) zusammen und errechnen ein relatives risiko von 3,0 (95 % ki 2,0-4,4) für das auftreten einer neonatalen symptomatik nach ssri-exposition in der spätschwangerschaft gegenüber einer ausschließlich in der frühschwangerschaft exponierten und einer unbehandelten kontrollgruppe. soweit klinisch vertretbar, kann mit der patientin eine reduktion bzw. auch das vorübergehende absetzen des antidepressivums vor der geburt vereinbart werden, um den nicht selten beobachteten anpassungsstörungen des neugeborenen entgegen zu wirken. das notwendige zeitintervall richtet sich dabei nach der halbwertszeit des medikamentes. langzeitentwicklung. eine studie an 31 müttern mit ssri im vergleich zu 13 ebenfalls erheblich depressiven frauen ohne medikation beobachtete bei den exponierten kindern signifikant geringere werte beim apgar-score, bei einigen psychomotorischen parametern sowie bei feinmotorischen kontrollfunktionen. die übrigen mentalen entwicklungsparameter unterschieden sich nicht. untersucht wurden kinder im alter zwischen 6 und 40 monaten (casper 2003). auch mattson und mitarbeiter (2004) verglichen 3 bis 34 monate alte, pränatal ssri exponierte kinder mit einer kontrollgruppe, die unverdächtigen medikamenten ausgesetzt war. dabei zeigten die mit ssri exponierten etwas häufiger psychomotorische entwicklungsrückstände, jedoch keine vermehrten auffälligkeiten bei den mentalen entwicklungsparametern des bayley-tests. oberlander und mitarbeiter (2005) fanden in einer kleinen studie eine eingeschränkte mimik und herzfrequenzvariabilität nach schmerzreiz im alter von 2 monaten bei kindern mit ssri-exposition. bei anderen untersuchungen wurden keine eindeutigen entwicklungsunterschiede festgestellt, z. b. bei psychomotorischen tests im alter von 2 und 8 monaten (oberlander 2004) . ein weiterer vergleich zwischen pränatal ssri-exponierten (129 fluoxetin, 28 paroxetin, 32 sertralin) und kontroll-kindern (209 trizyklische antidepressiva, 185 unbehandelt) im alter von 2 jahren fand ebenfalls keine psychomotorischen entwicklungsunterschiede (simon 2002) . heikkinen und mitarbeiter (2002) beobachteten keine neurologischen differenzen im alter von einem jahr bei 11 mit citalopram exponierten kindern gegenüber 10 nicht exponierten. nulman und mitarbeiter (2002) sahen keine auffälligkeiten bei 40 fluoxetin exponierten kindern im alter zwischen 15 und 71 monaten. es ergaben sich keine hinweise auf teratogenität bei mehreren hundert ausgewerteten schwangerschaften einer studie der europäischen teratologischen arbeitsgruppe entis sowie in anderen kleinen fallserien (review in hallberg und sjöblom 2005) und bei über 1.600 im schwedischen medizinischen geburtsregister erfassten schwangerschaften (hallberg und sjöblom 2005 , ericson 1999 escitalopram ist ein aktives isomer des citaloprams. von uns wurden 10 exponierte schwangere prospektiv erfasst. unter den 7 lebendgeborenen gab es keine fehlbildung. zwei schwangerschaften endeten als spontanabort, eine wurde aus persönlichen gründen abgebrochen. die datenlage ist für eine differenzierte beurteilung noch unzureichend. tierexperimentell wurde keine teratogenität beobachtet. fehlbildungsrisiko. mehrere studien mit insgesamt über 2.000 schwangerschaften und eine ähnlich große zahl vom hersteller registrierter fälle ergaben keine hinweise auf ein substantiell erhöhtes fehlbildungsrisiko , hallberg 2005 , hines 2004 b, pastuszak 1993 . ein gering erhöhtes risiko für herzfehlbildungen wurde jedoch kürzlich diskutiert (diav-citrin 2006) . auch eine leicht erhöhte abortrate wurde beschrieben, ohne die ursachen -grunderkrankung oder medikation -klären zu können (chambers 1996) . außerdem wurden ein vermehrtes auftreten kleinerer fehlbildungen, sowie bei behandlung im letzten trimenon von frühgeburten und anpassungsstörungen der neugeborenen beobachtet (übersicht in hines 2004, cohen 2000 , chambers 1996 . bei kritischer sicht erscheint eine kausale assoziation bei den kleinen fehlbildungen wenig wahrscheinlich und wird auch von anderen autoren bezweifelt (robert 1996) . anpassungsstörungen nach der geburt. bei manchen neugeborenen wurden wenige tage dauernde, als entzug oder serotonerge überstimulation (laine 2003 ; siehe auch einleitung zu den ssri) interpretierte symptome wie zittrigkeit, übererregbarkeit und erhöhter muskeltonus beobachtet, wenn bis zum ende der schwangerschaft behandelt wurde (zusammenfassung in hines 2004 , mhanna 1997 , chambers 1996 , spencer 1993 . bei einem von uns beobachteten fall traten bei dem frühgeborenen kind ausgeprägte extrapyramidale symptome auf. fluoxetin hat einschließlich seiner aktiven metaboliten mit bis zu 9 tagen die längste halbwertszeit unter den ssri und ist daher in hinsicht auf die neonatalperiode problematischer als andere ssri. auf eine möglicherweise erhöhte blutungsbereitschaft postpartal wird ebenfalls hingewiesen (mhanna 1997) . langzeitentwicklung. bei einer nachuntersuchung im vorschulalter von 55 vorwiegend im 1. trimenon exponierten kindern ergaben sich keine abweichungen bezüglich intelligenzentwicklung, verhalten und sprachentwicklung gegenüber zwei vergleichsgruppen mit amitriptylin oder ohne medikation (nulman 1997) . eine spätere prospektive untersuchung derselben autorengruppe findet auch bei kindern, deren mütter während der gesamten schwangerschaft fluoxetin (40 mutter-kind-paare; davon 18 bereits in der studie von 1997 erfasst) genommen hatten, keine arzneispezifischen auffälligkeiten in der entwicklung im alter zwischen 15 und 71 monaten. die dauer der depression hatte jedoch auswirkungen auf den intelligenzquotienten und die häufigkeit depressiver episoden auf die sprachentwicklung. die autoren leiten daraus die notwendigkeit einer therapie bei schwangeren ab (nulman 2002) . keine substantiellen hinweise auf spezifische teratogene effekte haben sich bisher bei mehreren hundert schwangerschaften unter fluvoxamin gezeigt (hallberg 2005 ein erhöhtes risiko für eine omphalocele (or 6,3; 95 % ki 2,0-19,6), nicht aber für andere fehlbildungen, fanden alwan und mitarbeiter (2005) auf der basis von geburts-bzw. fehlbildungsregisterdaten. tierexperimentell ergab sich bei paroxetin bisher keine teratogenität. insgesamt sind die schwachen hinweise auf das häufigere auftreten von (herz-)fehlbildungen unter paroxetin zurückhaltend zu bewerten, da sie nur in einigen analysen beobachtet wurden, und die gesamtrate aller fehlbildungen nicht erhöht zu sein scheint. anpassungsstörungen nach der geburt. bei behandlung bis zur geburt wurden wiederholt symptome beschrieben, u. a. übererregbarkeit, schlafund trinkstörungen, tremor, erhöhter muskeltonus, atemnotsyndrom und hypoglykämie, die eine stationäre überwachung erforderlich machten (übersicht in moses-kolko 2005 , sanz 2005 , jaiswal 2003 ). herbst und gortner (2003) empfehlen, bei symptomen einer neonatalen enzephalopathie differentialdiagnostisch auch an eine paroxetinbehandlung der mutter zu denken. die symptome beginnen in den ersten lebenstagen und dauern im extremfall einen monat, meist aber nicht länger als 1-2 wochen. in einer studie mit 55 kindern waren 12 betroffen (costei 2002) . sanz (2005) berichtete über spontanmeldungen an das internationale who-drug-monitoring-zentrum in uppsala, schweden. von insgesamt 93 fällen mit einer durch ssri induzierten symptomatik bei neugeborenen (davon 13 mit krampfanfällen) war paroxetin mit 64 überproportional häufig betroffen. neben rezeptorspezifischen unterschieden zwischen den ssri erörtern die autoren als ursache für eine entzugssymptomatik die verkürzte halbwertszeit des mittels, nachdem die hemmung des cytochrom-p450-2d6-enzyms durch das arzneimittel selbst nach der geburt entfällt. in einem weiteren fallbericht wies ein lethargisches reifes neugeborenes als einziges symptom eine fehlende schmerzreaktion in den ersten beiden lebenswochen auf (morag 2004) . andere autoren fanden keine häufung neonataler probleme bei paroxetin im vergleich zu anderen ssri oder trizyklika . zwei fallberichte diskutieren den zusammenhang einer paroxetinbehandlung in der spätschwangerschaft mit einer thrombozytenfunktionsstörung, die zu subarachnoidalblutung bzw. ventrikelblutung und krampfanfällen beim (reifen) neugeborenen führte (duijvestijn 2003 , salvia-roiges 2003 . zur langzeitentwicklung nach pränataler ssri-exposition siehe einleitung dieses abschnitts. weit über 500 dokumentierte schwangerschaftsverläufe haben keine hinweise auf teratogene effekte erbracht , übersicht in hallberg 2005 , hendrick 2003 , chambers 1999 , ericson 1999 , kulin 1998 , eigene erfahrungen), und auch tierexperimentell gibt es keinen anhalt für teratogenität. nach gabe von sertralin wurden zittrigkeit, unruhe, übererregbarkeit, erhöhter muskeltonus und schrilles schreien beobachtet und zunächst als neonataler entzug interpretiert (chambers 1999 , kent 1995 . wie bei den anderen ssri können diese symptome auch zeichen einer serotonintoxizität sein, dazu gehört auch der fall eines nystagmus beim neugeborenen (oca und donn 1999 ; siehe auch einleitung zu den ssri). empfehlung für die praxis: ssri gehören zu den mitteln der wahl bei therapiebedürftigen depressionen in der schwangerschaft. die gut untersuchten und in der schwangerschaft i.a. gut verträglichen mittel sertralin und citalopram sollten bei einer neueinstellung bevorzugt werden. eine unter therapie mit einem anderen ssri stabile patientin sollte -zumal während einer schwangerschaftdiese medikation unverändert fortsetzen, um keine für mutter und kind bedrohlichen krisen zu provozieren. die exposition mit einem weniger gut erprobten ssri im 1. trimenon rechtfertigt weder einen risikobegründeten schwangerschaftsabbruch noch invasive diagnostik (siehe kapitel 1). eine ultraschallfeindiagnostik sollte jedoch angeboten werden. bei gabe von ssri bis zur geburt müssen anpassungsstörungen und möglicherweise auch eine erhöhte blutungsbereitschaft beim neugeborenen bedacht werden. daher sollte in den ersten lebenstagen die beobachtung des neugeborenen gewährleistet sein, am besten durch entbindung in einem perinatologischen zentrum. soweit klinisch vertretbar, sollte mit der patientin eine reduktion bzw. auch das vorübergehende absetzen des antidepressivums vor der entbindung vereinbart werden; dabei richtet sich das erforderliche zeitintervall nach der halbwertszeit des medikamentes. aufgrund der sehr langen halbwertszeit ist dieses vorgehen besonders bei fluoxetin anzuraten. inaktiviert. monoaminooxidase-hemmstoffe sind strukturell dem amphetamin verwandt. therapeutisch wird heute vorwiegend moclobemid und wegen der dabei erforderlichen strengen diät nur noch selten tranylcypromin (jatrosom ® ) eingesetzt. unter mao-hemmern kann ein hypertonus in der schwangerschaft verstärkt und die plazentaperfusion gemindert werden mit negativen auswirkungen auf die fetale entwicklung. außerdem können mao-hemmer eine tokolyse mit betarezeptorenblockern aufheben und unter der geburt mit narkotika interagieren. eine ältere fallsammlung von 21 schwangeren, die im 1. trimenon mit mao-hemmstoffen behandelt wurden, davon 13 mit tranylcypromin , sowie ein bericht über 2 kinder mit anomalien und über plazentainfarkte (kennedy 2000) atomoxetin ist ein selektiver noradrenalin-wiederaufnahme-hemmer, der kürzlich zur behandlung der aufmerksamkeitsdefizit-hyperaktivitätsstörung zugelassen wurde. im gegensatz zu methylphenidat gehört es nicht zu den psychostimulanzien. die gefahr einer überdosierung mit dem risiko von krampfanfällen wurde im zusammenhang mit gleichzeitig gegebenen und ebenfalls über das cytochrom-p450-isoenzym-2d6 verstoffwechselten antidepressiva (paroxetin, fluoxetin, bupropion) erörtert. erfahrungen in der schwangerschaft liegen nicht vor. der wirkmechanismus von bupropion, das vor allem zur raucherentwöhnung verwendet wird und in der bundesrepublik als antidepressivum nicht zugelassen ist, ist nicht genau bekannt. zu duloxetin, einem serotonin-noradrenalin-wiederaufnahme-hemmstoff (snri), das zunächst als urologikum (yentreve ® ) zur behandlung der belastungsharninkontinenz zugelassen wurde, liegen bisher keine ausreichenden erfahrungen beim menschen vor, die aussagen zum teratogenen potenzial erlauben. tierexperimentell wurden bei kaninchen kardiovaskuläre und skelettfehlbildungen bei dosen beobachtet, die unterhalb des maximalen klinischen bereichs lagen. wie bei anderen serotonerg wirkenden antidepressiva muss auch bei duloxetin mit toxischen symptomen wie übererregbarkeit beim neugeborenen in den ersten lebenstagen gerechnet werden. zu mirtazapin, einem noradrenerg und serotonerg wirkenden antidepressivum, finden sich bei rund 100 veröffentlichten , biswas 2003 , kesim 2002 , saks 2001 bzw. von uns dokumentierten schwangerschaftsverläufen mit behandlung vorwiegend im 1. trimenon keine hinweise auf teratogenität. auch tierexperimentell liegen keine hinweise auf teratogenität vor. mirtazapin wird auch bei hyperemesis gravidarum eingesetzt (guclu 2005 , rohde 2003 , dorn 2002 , saks 2001 . zu nefazodon, das die wiederaufnahme von noradrenalin und serotonin hemmt, liegen fast 100 publizierte, vorwiegend im 1. trimenon exponierte schwangerschaften vor , einarson 2003 . weder diese daten (fehlbildungsrate 1,6 %) noch tierexperimentelle ergebnisse deuten bisher auf teratogenität hin. oxitriptan ist die physiologische vorstufe des neurotransmitters serotonin, das dessen konzentration im zns erhöht. ausreichende erfahrungen zur schwangerschaft liegen nicht vor. dies gilt auch für tianeptin, das im gehirn die aufnahme des serotonins erhöht. trazodon ist strukturell dem nefazodon verwandt und besitzt sedative eigenschaften. es wird auch als hypnotikum verschrieben und hat sich bei etwa 70 publizierten schwangerschaftsverläufenmeistens im 1. trimenon angewendet -bisher nicht als teratogen erwiesen (einarson 2003 , mcelhatton 1996 . gleiches gilt für tierexperimentelle ergebnisse. trazodon ist strukturell dem nefazodon verwandt und besitzt sedative eigenschaften. es wird auch als hypnotikum verschrieben und hat sich bei etwa 70 publizierten schwangerschaftsverläufen -meistens im 1. trimenon -bisher nicht als teratogen erwiesen (einarson 2003 , mcelhatton 1996 . gleiches gilt für tierexperimentelle ergebnisse. zu venlafaxin, einem so genannten bizyklischen antidepressivum, das die wiederaufnahme von noradrenalin und serotonin hemmt, liegen einschließlich einer kontrollierten studie mit 150 exponierten schwangeren publizierte erfahrungen an etwa 200 schwangeren vor und 80 aus unserer eigenen datenbank, die bisher keine hinweise auf teratogene effekte geben , ellingrod 1994 . auch im tierversuch wurde keine teratogenität beobachtet. entzugserscheinungen nach der geburt sind nicht auszuschließen. die wenigen bis einige dutzend dokumentierten schwangerschaften zu amineptin, amoxapin, medifoxamin, dem noradrenalin-wiederaufnahme-hemmstoff reboxetin (eigene beobachtungen) und viloxazin (mcelhatton 1996 , brunel 1994 ) ergeben keine spezifischen teratogenen wirkungen, reichen aber für eine differenzierte risikobewertung nicht aus. das gleiche gilt für das heute auch von schwangeren häufig eingenommene, aber formal unzureichend untersuchte, pflanzliche antidepressivum johanniskraut (hypericin; z. b. esbericum ® ; siehe auch kapitel 2.19). empfehlung für die praxis: die hier genannten antidepressiva sollten -mit ausnahme von hypericin und ggf. mirtazapin und venlafaxin -in der schwangerschaft primär nicht verschrieben werden, da keine ausreichenden erfahrungen beim menschen vorliegen. andererseits sollte eine stabil eingestellte patientin während der schwangerschaft nicht auf andere medikamente umgesetzt werden, um für mutter und kind keine bedrohlichen krisen zu provozieren. die einnahme im 1. trimenon rechtfertigt keinen risikobegründeten schwangerschaftsabbruch (siehe kapitel 1.15). eine ultraschallfeindiagnostik kann jedoch angeboten werden, um eine normalentwicklung des fetus zu bestätigen. entzugserscheinungen nach geburt sind nicht auszuschließen. daher ist in den ersten beiden lebenstagen eine zuverlässige beobachtung des neugeborenen zu gewährleisten und eine entbindung in einem perinatologischen zentrum anzustreben. g 2.11.6 antipsychotische behandlung neuroleptika rufen eine psycho-physiologische umstimmung bei gesunden und psychisch kranken hervor, bei der die intellektuellen fähigkeiten erhalten bleiben. sie wirken wahrscheinlich über eine blockade zerebraler dopaminrezeptoren. zur gruppe der neuroleptika zählen (schwach und stark wirksame) phenothiazine, thioxanthene, butyrophenone als erste generation und die so genannten atypischen zu amisulprid (z. b. solian ® ), einem benzamidderivat und selektiven dopamin-d 2 -und -d 3 -rezeptorantagonisten, liegen nur einzelfallberichte vor, die bisher keine spezifische teratogenität erkennen lassen. wir überblicken 11 prospektiv dokumentierte schwangerschaften, von denen eine als spontanabort endete. von den 10 lebend geborenen kindern wies keines eine fehlbildung auf. allerdings reicht diese geringe zahl für eine differenzierte risikobewertung nicht aus. zur perinatalen dosisanpassung siehe "empfehlung für die praxis" weiter unten. aripiprazol (abilify ® ) wird als erstes atypisches neuroleptikum der 2. generation bezeichnet. es zeichnet sich aus durch gemischten dopaminergen agonismus (in regionen verminderter dopaminerger aktivität, beispielsweise im mesokortikalen bereich) und antagonismus (in regionen mit erhöhter dopaminkonzentration, z. b. im mesolimbischen bereich). im gegensatz zu den klassischen neuroleptika und manchen atypika wie dem risperidon bewirkt es keine erhöhung, sondern tendentiell sogar eher eine erniedrigung des prolaktins. besonders beim umsetzen von einem klassischen neuroleptikum (phenothiazine, butyrophenone wie haloperidol) muss mit einer ungeplanten schwangerschaft gerechnet werden, da sich durch den geringeren einfluss auf den prolaktinspiegel im vergleich zu den klassischen neuroleptika die fertilität verbessern kann. daher muss eine wirksame kontrazeption sichergestellt werden. bisher sind keine wechselwirkungen mit kontrazeptiva bekannt. für eine bewertung des risikos in der schwangerschaft liegen weder ausreichende daten noch einzelfallhinweise auf spezifische teratogene ereignisse vor. tierexperimentell fanden sich bei ratten vermehrt zwerchfellhernien und bei kaninchen skelettauffälligkeiten. zur perinatalen dosisanpassung siehe "empfehlung für die praxis" weiter unten. im gegensatz zu den klassischen neuroleptika sind menstruationszyklus und fertilität bei olanzapin (zyprexa ® ) mit seinem kombinierten d 2 /5-ht 2a -rezeptorantagonismus kaum beeinträchtigt. der prolaktinspiegel ist nur in geringem maße und nur vorübergehend erhöht. besonders beim umsetzen von einem klassischen neuroleptikum (phenothiazine, butyrophenone wie haloperidol) muss mit einer ungeplanten schwangerschaft gerechnet werden, da sich durch den geringeren einfluss auf den prolaktinspiegel im vergleich zu den klassischen neuroleptika die fertilität verbessern kann. daher muss eine wirksame kontrazeption sichergestellt werden. bisher sind keine wechselwirkungen mit kontrazeptiva bekannt. olanzapin hat sich tierexperimentell bei ratten und kaninchen nicht als teratogen erwiesen. etwa 200 schwangerschaften wurden inzwischen ausgewertet, die z. t. mit den rund 240 vom hersteller gesammelten fallberichten identisch sind. diese daten ergeben bisher keine hinweise auf embryo-oder fetotoxische effekte , levinson 2003 , ernst 2002 , mendhekar 2002 , biswas 2001 , malek-ahmadi 2001 , nagy 2001 , neumann 2001 , goldstein 2000 , kirchheiner 2000 . auch die von uns prospektiv erfassten 63 schwangerschaften mit nur einer großen fehlbildung ergeben keinen hinweis auf teratogenität. nach anwendung bis zum ende der schwangerschaft wurden sedierung und anhaltender ikterus bei einem säugling im zusammenhang mit der mütterlichen olanzapineinnahme diskutiert (goldstein 2000) . bei drei retrospektiv erfassten kindern, deren mütter bis zur geburt behandelt wurden, traten in der neonatalzeit krampfanfälle auf (goldstein 2000, eigene erfahrungen). da unter den prospektiv dokumentierten fällen keine krampfanfälle beobachtet wurden, ist ein hohes krampfrisiko nicht gegeben, ein ursächlicher zusammenhang ist aber nicht auszuschließen. die lange halbwertszeit von etwa 30 stunden und die noch nicht voll entwickelte exkretionsleistung beim neugeborenen könnten derartige toxische wirkungen begünstigen. von 44 lebend geborenen kindern in unserer prospektiven datenbank wiesen 8 (18 %) vorübergehende, nicht durch frühgeburtlichkeit bedingte symptome (vorwiegend zittrigkeit) auf. zur perinatalen dosisanpassung siehe "empfehlung für die praxis" weiter unten. beim umsetzen von einem klassischen neuroleptikum (phenothiazine, butyrophenone wie haloperidol) auf quetiapin (seroquel ® ) mit seinem kombiniertem d 2 /5-ht 2a -rezeptorantagonismus muss mit einer ungeplanten schwangerschaft gerechnet werden, da durch den geringeren einfluss auf den prolaktinspiegel im vergleich zu den klassischen neuroleptika die fertilität ansteigen kann. daher muss eine wirksame kontrazeption sichergestellt werden. bisher sind keine wechselwirkungen mit kontrazeptiva bekannt. etwa 40 bisher veröffentlichte schwangerschaftsverläufe und 150 vom hersteller gesammelte fallberichte lassen keine spezifische teratogenität oder -soweit untersucht -bleibende funktionsstörungen erkennen, sie sind aber unzureichend für eine differenzierte risikobewertung (mckenna 2005, pace zitiert in gentile 2004 , taylor 2003 , tényi 2002 . von weiteren 42 in unserer datenbank prospektiv erfassten schwangerschaften wiesen 2 (statistisch nicht signifikant gegenüber einer nicht behandelten kontrollgruppe) eine große fehlbildung auf: vorhofseptumdefekt, lippen-gaumen-spalte. die mutter des kindes mit der spaltbildung rauchte 20 zigaretten täglich und war außerdem mit olanzapin behandelt worden. rauchen wird bei frauen mit einem gleichzeitig vorliegenden defekt des enzyms tgf-alpha als risikofaktor für spaltbildungen diskutiert. im tierversuch ist keine teratogenität bekannt. von den 36 lebend geborenen kindern in unserer prospektiven datenbank wiesen 3 (9 %) vorübergehende, nicht durch frühgeburtlichkeit bedingte anpassungssymptome (vorwiegend zittrigkeit) auf. zur perinatalen dosisanpassung siehe "empfehlung für die praxis" weiter unten. beim umsetzen von einem klassischen neuroleptikum (phenothiazine, butyrophenone wie haloperidol) auf risperidon (risperdal ® ), einem benzisoxazolderivat und kombiniertem d 2 /5-ht 2a -rezeptorantagonisten, muss mit einer ungeplanten schwangerschaft gerechnet werden, da sich durch den geringeren einfluss auf den prolaktinspiegel im vergleich zu den klassischen neuroleptika die fertilität normalisieren kann. daher muss eine wirksame kontrazeption sichergestellt werden. bisher sind keine wechselwirkungen mit kontrazeptiva bekannt. zu risperidon gibt es etwa 60 publizierte fallberichte , ratnayake 2002 , mackay 1998 ) und rund 200 vom hersteller gesammelte datensätze sowie 32 von uns prospektiv erfasste schwangerschaftsverläufe, die bisher keine spezifische teratogenität erkennen lassen. von den 32 in unserer datenbank prospektiv erfassten schwangerschaften wies 1 kind eine große fehlbildung auf. dies ist gegenüber der kontrollgruppe statistisch nicht signifikant. allerdings erlaubt die geringe fallzahl keine differenzierte risikobewertung. im tierversuch ist keine teratogenität bekannt. zur perinatalen dosisanpassung siehe "empfehlung für die praxis" weiter unten. beim umsetzen von einem klassischen neuroleptikum (phenothiazine, butyrophenone wie haloperidol) auf ziprasidon (zeldox ® ), einem kombiniertem d 2 /5-ht 2a -rezeptorantagonisten, muss mit einer ungeplanten schwangerschaft gerechnet werden, da durch den geringeren einfluss auf den prolaktinspiegel im vergleich zu den klassischen neu-roleptika die fertilität steigen kann. daher muss eine wirksame kontrazeption sichergestellt werden. bisher sind keine wechselwirkungen mit kontrazeptiva bekannt. zu ziprasidon gibt es nur wenige publizierte fallberichte. von den 12 in unserer datenbank prospektiv erfassten schwangerschaften wies ein kind (von 10 lebendgeborenen) eine große fehlbildung auf (vorhofseptumdefekt). dies ist gegenüber einer gesunden kontrollgruppe statistisch nicht signifikant und lässt keine spezifische teratogenität erkennen, ist aber unzureichend für eine differenzierte risikobewertung. im tierversuch hat sich ziprasidon beim kaninchen als teratogen erwiesen (herzfehlbildungen). zur perinatalen situation und dosisanpassung um die geburt siehe abschnitt "empfehlung für die praxis". empfehlung für die praxis: ein atypisches neuroleptikum kann bei entsprechender indikation in der schwangerschaft eingesetzt werden, wobei möglichst länger eingeführte präparate bevorzugt werden sollten. olanzapin ist das bisher am umfangreichsten in der schwangerschaft dokumentierte mittel aus dieser gruppe. da olanzapin den blutzuckerspiegel erhöhen kann, muss ein gestationsdiabetes ausgeschlossen werden. die anderen genannten atypischen neuroleptika sind aufgrund der geringeren erprobung reservemittel in der schwangerschaft, die unter stabiler therapie während einer schwangerschaft jedoch nicht umgesetzt werden sollten, um keine für mutter und kind bedrohliche krise zu provozieren. wegen allgemeiner nebenwirkungen sollte eine neueinstellung von clozapin in der schwangerschaft unterbleiben, eine gut auf clozapin eingestellte patientin muss jedoch nicht umgestellt werden. generell sind sorgfältige schwangerschaftsüberwachung und engmaschige psychiatrische kontakte unerlässlich, um rechtzeitig krisen bei der mutter und entwicklungskomplikationen beim fetus (frühgeburtsbestrebungen, wachstumsretardierung) begegnen zu können. nach exposition im 1. trimenon sollte die normale entwicklung des fetus mittels ultraschallfeindiagnostik bestätigt werden. die einnahme eines atypischen neuroleptikums rechtfertigt keinen risikobegründeten schwangerschaftsabbruch (siehe kapitel 1.15). bei therapie im letzten schwangerschaftsdrittel sollte, wenn möglich, die dosis in den tagen vor der geburt reduziert werden, um symptome beim neugeborenen zu vermeiden. in den ersten beiden lebenstagen muss eine zuverlässige beobachtung des neugeborenen gewährleistet sein, daher sollte die entbindung möglichst in einem perinatalzentrum erfolgen. bei erkrankungen mit hoher rezidivgefahr (wie etwa bipolare störungen) sollte bedacht werden, dass eine zu rasche dosisreduktion vor geburt in dieser für die mutter vulnerablen phase probelmatisch sein kann und postpartal das höchste risiko für ein rezidiv besteht. die notwendigkeit einer postpartalen dosiserhöhung in therapeutische bzw. hochtherapeutische bereiche muss frühzeitig besprochen werden. lithiumsalze werden nach oraler gabe gut resorbiert und zu mehr als 95 % unverändert mit dem urin ausgeschieden, ihre halbwertszeit beträgt 24 stunden. bei schwangeren ist die lithiumausscheidung durch die niere um 50-100 % gesteigert. lithium ist plazentagängig und erreicht im fetus ebenso hohe konzentrationen wie im mütterlichen serum. in den 70er jahren wurde lithium eine erhebliche teratogenität unterstellt und herzfehlbildungen als folge der behandlung im 1. trimenon angesehen, insbesondere die sonst seltene ebstein-anomalie mit einer fehlanlage der trikuspidalklappe. zur dokumentation exponierter feten wurde das so genannte "lithium-baby-register" 1968 in dänemark eingerichtet und dann international ausgeweitet. als es 1979 geschlossen wurde, lagen berichte über 225 kinder vor, davon hatten 25 (11 %) fehlbildungen, in 18 fällen am herzen und den großen gefäßen. andere anomalien betrafen die äußeren ohranlagen, das gehirn, die ureter und das endokrine system (übersicht bei kozma 2005) . der hohe anteil von kindern mit fehlbildungen erklärt sich aus der retro-spektiven fallerfassung, bei der wie üblich auffällige verläufe überrepräsentiert sind. spätere prospektive kohorten-und retrospektive fall-kontroll-untersuchungen ergaben nur zum teil erhöhte fehlbildungsraten, u. a. auch für herzfehler. doch scheint das teratogene risiko deutlich geringer zu sein, als früher angenommen (kozma 2005 , cohen 1994 , jacobson 1992 , källén 1991 , zalzstein 1990 (pinelli 2002) , krampfanfälle und hypothyreose wurden beschrieben (malzacher 2003 , zegers 2003 , frassetto 2002 , llewellyn 1998 . diese toxischen effekte des lithiums besserten sich meist innerhalb von 1-2 wochen nach der geburt. bei neugeborenen mit ausgeprägter hypothyreose und konnataler struma wurde jedoch auch über eine wochenlang erforderliche thyroxinsubstitution berichtet (frassetto 2002) . länger anhalten kann auch ein so genanntes "floppy-infant-syndrom" mit lethargie, trinkschwäche, tachypnoe, tachykardie, zyanose, temperaturregulationsstörung und muskelhypotonie. die spätere entwicklung der kinder verläuft anscheinend normal (kozma 2005) . empfehlung für die praxis: ist eine lithiumtherapie in der schwangerschaft erforderlich, sollten gleich bleibend niedrige serumkonzentrationen angestrebt werden, insbesondere im 1. trimenon. die mütterliche tagesdosis (üblicherweise 300 bis höchstens 1200 mg/tag) sollte auf 3-4 einzeldosen verteilt werden. eine ultraschallfeindiagnostik bzw. eine fetale echokardiographie sind nach exposition im 1. trimenon zu empfehlen. die schwangere soll keine salzarme diät einhalten und keine diuretika einnehmen. letztere können einen paradoxen antidiuretischen effekt bei gleichzeitiger lithiumtherapie entfalten. wegen veränderungen im flüssigkeitshaushalt während der schwangerschaft sollte die serumkonzentration (0,5-0,8 meq/l) monat-lich kontrolliert und die dosis dann ggf. erhöht werden. im letzten schwangerschaftsmonat sind wöchentliche kontrollen erforderlich und vor der geburt alle 2 tage. in der woche vor der geburt sollte, wenn möglich, die dosis um 30-50 % herabgesetzt werden. eine dehydratation ist ggf. mit parenteraler flüssigkeitssubstitution zu therapieren. nach der geburt kann die vor der schwangerschaft übliche dosis wieder eingenommen werden. dabei muss zunächst weiter engmaschig der spiegel kontrolliert werden und wegen der erneuten umstellung des flüssigkeitshaushalts die dosis ggf. vorübergehend nach unten angepasst werden. aufgrund der unreifen renalen elimination insbesondere in den ersten lebenstagen ist auf toxische symptome beim kind zu achten. außerdem muss eine hypothyreose ausgeschlossen werden. die entbindung sollte in einem perinatalzentrum erfolgen. gerade bei bekannter bipolarer störung muss bei der planung der medikation für die mutter das hohe postpartale rezidivrisiko bedacht werden und zwar sowohl für postpartale depressionen als auch für manien. . tierexperimentell finden sich hinweise auf teratogenität. kavain ist zusammen mit anderen kavalactonen einer der hauptinhaltsstoffe aus der kava-kava-wurzel (piper methysticum, rauschpfeffer). diesem wirkstoff mit antidopaminerger und daher auch prolaktinerger wirkung, werden psychostabilisierende eigenschaften zugeschrieben. untersuchungen zur anwendung bei schwangeren liegen nicht vor, allerdings gibt es bisher auch keine hinweise auf teratogene effekte. aufgrund seiner hepatotoxizität hat es in den vergangenen jahren an bedeutung verloren. meprobamat ist einer der ältesten tranquilizer. seit der einführung der benzodiazepine hat meprobamat therapeutisch keine große bedeutung mehr. in einer studie mit 400 frauen, die meprobamat im 1. trimenon erhalten hatten, war die häufigkeit von herzfehlbildungen erhöht (milkovich 1974 diazepam wird nach oraler gabe rasch resorbiert und im blut überwiegend an plasmaproteine gebunden transportiert. in der leber erfolgen eine hydroxylierung und die metabolisierung zu dem noch aktiven desmethyldiazepam, das nach glucuronidierung über die nieren ausgeschieden wird. die halbwertszeit beträgt 1-2 tage, beim neugeborenen ist sie aufgrund verminderter clearance erheblich verlängert. orale kontrazeptiva können durch hemmung des metabolismus die alprazolam-oder diazepamkonzentration erhöhen. außerdem können sie die enterale absorption von benzodiazepinen verändern und zu einer wirkungsabschwächung von lorazepam durch einwirkung auf dessen kinetik führen. andererseits ist eine beeinträchtigung oraler kontrazeptiva bei benzodiazepintherapie durch cytochrom-p450-enzyminduktion möglich . diazepam ist gut plazentagängig. unter der geburt ist die konzentration im nabelvenenblut bis zu 3fach höher als im mütterlichen blut. fehlbildungsrisiko. für benzodiazepine besteht nach heutigem wissen kein nennenswertes teratogenes risiko, obwohl die vorliegenden studien ein teilweise widersprüchliches bild ergeben. die meisten erfahrungen liegen zu diazepam vor. im zusammenhang mit einer benzodiazepintherapie im 1. trimenon wurden herzfehlbildungen, lippen-kiefer-gaumen-spalten, inguinalhernien und komplexe andere fehlbildungen beschrieben (übersicht bei mcelhatton 1994). andere studien konnten teratogene effekte nicht bestätigen , patuszak 1996 . in einer metaanalyse zeigten die gesammelten daten von kohortenstudien mit schwangeren, die mit benzodiazepinen behandelt wurden, keine auffälligkeiten. die zusammenfassende analyse der verfügbaren retrospektiven fall-kontroll-studien erbrachte hingegen ein erhöhtes risiko für große fehlbildungen bzw. für isolierte mundspaltbildungen nach behandlung der mütter mit benzodiazepinen (dolovitch 1998). auch rodriguez-pinilla (1999) erörtert im zusammenhang mit zwei retrospektiven fall-kontroll-untersuchungen mit daten aus fehlbildungsregistern schwache, aber statistisch signifikante assoziationen zwischen benzodiazepin-exposition im 1. trimenon und spaltbildungen, intestinalen atresien und mikrozephalie. zu alprazolam ergaben sich bislang keine hinweise auf teratogenität (schick-boschetto 1992 , st clair 1992 . zwei retrospektive fall-kontroll-untersuchungen mit rund 400 mit chlordiazepoxid exponierten schwangeren , sowie 10 patientinnen mit alprazolam, etwa 100 mit clonazepam (details siehe kapitel 2.10 antiepileptika), 18 mit medazepam, 18 mit nitrazepam und 13 mit tofisopam ergaben ebenfalls keine hinweise auf nennenswerte teratogene effekte , eros 2002 . bonnot und mitarbeiter (2001) fanden kein erhöhtes risiko für spezielle fehlbildungen bei benzodiazepinen insgesamt, jedoch eine assoziation zwischen analatresie und lorazepam: von 6 kindern mit anal-atresie, deren mütter benzodiazepine genommen hatten, waren 5 pränatal mit lorazepam exponiert. anpassungsstörungen nach der geburt. laegreid und mitarbeiter (1989) berichteten über acht kinder, deren mütter während der gesamten schwangerschaft arzneimittelabusus mit täglich mindestens 30 mg diazepam und mindestens 75 mg oxazepam betrieben hatten. alle kinder wiesen gesichtsdysmorphien auf, einige außerdem eine mikrozephalie sowie postpartal toxische symptome (apnoe) und entzugserscheinungen. später wurden unterschiedlich ausgeprägte mentale retardierungen, konzentrationsstörungen und hyperkinesien beobachtet. diesen falldarstellungen ist jedoch vorgehalten worden, art und umfang der exposition nicht ausreichend abgesichert und in einem fall ein zellweger-syndrom nicht ausgeschlossen zu haben. in nachfolgeuntersuchungen wurde bei den etwa 18 monate alten kindern eine besserung der symptomatik festgestellt (laegreid 1992) . als gesichert wird hingegen das risiko funktioneller störungen beim neugeborenen angesehen, wenn unter der geburt benzodiazepine hoch dosiert verabreicht wurden oder wenn über längere zeiträume, das letzte schwangerschaftsdrittel inbegriffen, regelmäßig diazepam oder andere benzodiazepine eingenommen wurden. einerseits muss nach hohen dosen sub partu mit atemdepression gerechnet werden, wie z. b. bei therapie einer eklampsie. andererseits kann nach andauernder exposition eine entzugssymptomatik mit unruhe, tremor, muskelhypertonus, erbrechen, durchfall auftreten, wie z. b. nach opiaten. auch zerebrale krampfanfälle in der neonatalphase sind möglich und ein wochen bis monate anhaltendes "floppy-infant-syndrom" mit muskelschlaffheit, lethargie, temperaturregulationsstörungen und trinkschwäche. aufgrund der akkumulation im fetus können im einzelfall schon geringe dosen diazepam (unter 10 mg) beim neugeborenen zu klinischen symptomen führen (peinemann 2001) . das neugeborene metabolisiert benzodiazepine wesentlich langsamer als der erwachsene. langzeitwirkungen einer pränatalen exposition auf die spätere entwicklung des kindes sind nicht abschließend geklärt. besorgnis erregende hinweise gibt es bisher aber nicht. benzodiazepine können in der peripartalphase bilirubin aus der albuminbindung im blut verdrängen und zumindest theoretisch einen icterus neonatorum verstärken. empfehlung für die praxis: bei strenger indikationsstellung sind benzodiazepine mittel der wahl zur behandlung einer angstsymptomatik und in bestimmten fällen auch von schlafstörungen in der schwangerschaft. sie sollten, auch nach ausschöpfung aller nicht medikamentöser behandlungsmöglichkeiten und medikamentöser alternativen (z. b. niedrig dosierte antidepressiva, wie etwa amitriptylin), nur kurzzeitig verordnet werden. eine dauertherapie im letzten tri-menon, z. b. als zusatzmedikation zur wehenhemmung oder eine behandlung am geburtstermin ist wegen möglicher neonataler komplikationen (siehe oben) besonders kritisch zu prüfen. in den ersten lebenstagen muss verstärkt auf symptome beim kind geachtet werden. nach möglichkeit sollte mit der werdenden mutter eine dosisreduktion rechtzeitig vor dem erwarteten geburtstermin besprochen werden (abhängig von der halbwertszeit). im fall einer therapie mit benzodiazepinen empfiehlt es sich, aufgrund der durch enzyminduktion verursachten unsicherheit hormoneller kontrazeption keine systemische hormontherapie, also auch keine oralen kontrazeptiva, vorzusehen, da selbst die gelegentlich empfohlene verdopplung der dosis nicht die gewünschte sicherheit garantiert. ein intrauterinsystem mit lokaler gestagenabgabe (mirena ® ) wäre zu bevorzugen oder bei etwas geringerer sicherheit ein intrauterinpessar (iud). nur wenn diese methoden nicht vertragen werden, ist eine höher dosierte hormonelle kontrazeption -ggf. mit einschränkungen der verlässlichkeit -in betracht zu ziehen. hierfür kommt eine durchgehende einnahme von täglich 2 dosen eines niedrig dosierten monophasischen präparates infrage und zwar im langzyklus durchgehend für 3-9 monate. g 2.11.17 zaleplon, zolpidem und zopiclon zaleplon (sonata ® ), zolpidem (z. b. stilnox ® ) und zopiclon (ximovan ® ) sind neuentwickelte hypnotika mit agonistischer wirkung am benzodiazepinrezeptor. sie sind chemisch nicht mit der gruppe der benzodiazepine verwandt. wegen des geringeren suchtpotenzials finden sie heute zunehmende verbreitung. untersuchungen an verschiedenen tierspezies lassen nach angaben der hersteller keine teratogenen effekte erkennen. zur anwendung von zaleplon gibt es keine ausreichenden erfahrungen für eine differenzierte risikobeurteilung in der schwangerschaft. zu zolpidem liegen auf der basis von einem dutzend im 1. trimenon exponierten schwangerschaften keine hinweise für teratogene eigenschaften vor (wilton 1998). für eine differenzierte risikobewertung reichen die daten jedoch nicht aus. in einer prospektiven studie mit 40 im 1. trimenon mit zopiclon behandelten schwangeren fanden sich keine auffälligkeiten gegenüber einer kontrollgruppe (diav-citrin 1999). zu eszopiclon (lunesta ® , estorra ® ), dem s-enantiomer des zopiclon, gibt es keine erfahrungen in der schwangerschaft. empfehlung für die praxis: die hier genannten arzneimittel sollten während der schwangerschaft nicht als hypnotika verordnet werden. eine dennoch erfolgte einnahme im 1. trimenon rechtfertigt keinen risikobegründeten schwan(arai 1997 , nomoto 1997 , von graevenitz 1996 . die mit ausnahme der älteren ergotaminabkömmlinge liegen zu den meisten dieser mittel keine ausreichenden erfahrungen in der schwangerschaft vor. hinweise auf ein erhebliches teratogenes potenzial beim menschen sind bisher nicht erkennbar. in gut begründeten einzelfällen ist die behandlung mit parkinsonmitteln auch im 1. trimenon akzeptabel, z. b. bei therapie eines prolaktinoms mit ergotaminderivaten oder von extrapyramidalen nebenwirkungen einer neuroleptika-therapie mit biperiden. bei restless-legs-symptomen sollten möglichst andere therapieoptionen genutzt werden. keines der hier erörterten mittel rechtfertigt, wenn es im 1. trimenon eingenommen wurde, einen risikobegründeten schwangerschaftsabbruch (siehe kapitel 1.15). eine ultraschallfeindiagnostik sollte jedoch angeboten werden, wenn eines der unzureichend untersuchten produkte im 1. trimenon eingenommen wurde. steyn dw, odendaal hj. the effect of oral ketanserin on fetal heart rate 7 tumor-nekrose-faktor-(tnf-) § -antikörper: adalimumab, etanercept, infliximab. auch corticosteroide sind zu den immunsuppressiva zu rechnen (siehe kapitel 2.15). zu den immunstimulanzien gehören interferone, kolonie-stimulierende faktoren (csf) und glatiramer. klinische erfahrungen liegen vor allem zu schwangerschaften nach nieren-und lebertransplantation und zur langzeittherapie mit azathioprin, ciclosporin und tacrolimus in kombination mit einem niedrig dosierten glucocorticoid (prednisolon) vor. insbesondere dann, wenn keine abstoßungsreaktion auftritt und die transplantation mindestens 1-2 jahre zurückliegt, ist die prognose für eine schwangerschaft gut. zwar wird häufiger per sectio entbunden, und es kommt vermehrt zu frühgeburten und zu intrauteriner wachstumsretardierung (small for gestational age) sowie zur passageren nierenfunktionsstörung beim neugeborenen. ein erhöhtes fehlbildungsrisiko oder bleibende funktionsdefizite sind aber aufgrund der vorliegenden erfahrungen nicht zu erwarten. bei einem vergleich von schwangerschaften organtransplantierter frauen einige jahre vor und nach transplantation zeigte sich, dass verschiedene befunde in beiden gruppen ähnlich häufig auftraten. das betrifft die rate an präeklampsie (22 %), an frühgeburten (46 %), niedrigerem geburtsgewicht (41 %), small for gestational age (16 %) und die säuglingssterblichkeit (5%). eine erhöhte fehlbildungsrate wurde in keiner der beiden gruppen festgestellt (källén 2005) . diese studie legt nahe, dass die geschilderten komplikationen in erster linie durch die schwere der mütterlichen erkrankung verursacht werden und nicht durch die transplantation oder die immunsuppressive therapie. die abortrate war in dem kollektiv vor transplantation höher als danach. zur antirheumatischen therapie siehe kapitel 2.12.7. g 2. azathioprin (aza) (z. b. imurek ® ) ist ein zur immunsuppression genutzter antimetabolit, der zu mehr als 80 % zu 6-mercaptopurin (6-mp) metabolisiert wird. von aza werden nach oraler gabe ca. 47 % resorbiert, während es bei 6-mp durchschnittlich nur 16 % sind . von vielen autoren wird das risiko für beide substanzen bei immunsuppressiven dosierungen als vergleichbar angesehen. aza wirkt in bakterientestsystemen mutagen und im tierexperiment teratogen. annähernd 40 studien bzw. fallserien mit insgesamt mehr als 1.000 schwangeren sowie weitere fallberichte zu 120 schwangerschaften lassen kein nennenswert erhöhtes fehlbildungsrisiko erkennen (berkovitch 2005 , moskovitz 2004 , armenti 2003 . nur fand anhand der daten aus dem dänischen geburtsregister bei einer fallzahl von nur 10 frauen eine signifikante erhöhung an grobstrukturellen fehlbildungen, perinataler sterblichkeit und frühgeburtlichkeit. wie andere zytotoxische substanzen vermag aza das intrauterine wachstum zu hemmen, so dass verschiedentlich ein erniedrigtes geburtsgewicht beobachtet wurde. dies kann allerdings auch folge der grunderkrankung oder der häufig gleichzeitig erfolgten glucocorticoidtherapie sein. eine leukopenie der mutter am ende der schwangerschaft kann auf eine neonatale hämatopoesehemmung und immunsuppression hinweisen (davison 1985) . bei 23 bar-oz 2001 , lamarque 1997 . intrauterine wachstumsverzögerung und eine erhöhte rate an frühgeburtlichkeit wurden beschrieben, jedoch sind diese befunde wahrscheinlich durch die mütterliche grunderkrankung bedingt. bei sechs im ersten lebensjahr untersuchten kindern fanden sich veränderungen bei den b-und t-lymphozyten sowie den natural-killer-zell-funktionen (nk), die aber offenbar klinisch nicht relevant waren (dipaolo 2000) . in zwei anderen untersuchungen zeigte sich keine veränderte immunreaktion bei kindern bis zum alter von 2 jahren (baarsma 1993) bzw. bis zum alter von 5 jahren (rieder 1997) . weder die untersuchung von rieder (1997) an 14 kindern, noch eine andere von an 20 kindern erbrachte hinweise auf neurologische störungen bzw. auf einschränkungen der intellektuellen entwicklung. ein einzelner fallbericht beschreibt ein 2-jähriges kind mit hepatoblastom nach mütterlicher behandlung mit ciclosporin während der gesamten schwangerschaft (roll 1997 (jain 1997) . wie bei anderen immunsuppressiva wurde ein vermehrtes auftreten von präeklampsie, frühgeburten, geringerem geburtsgewicht und schnittentbindungen beobachtet. die erfahrungen in der schwangerschaft beruhen auf retrospektiven fallberichten, fallserien (jain 2004 , rayes 1998 , einer kleinen prospektiven studie und auf der 1991 von arzneimittelherstellern eingerichteten "national transplantation registry" (armenti 2003). etwa 200 schwangerschaften sind unter tacrolimus dokumentiert, das in der regel zusammen mit prednison, aber auch mit anderen immunsuppressiva gegeben wird. ein nennenswertes teratogenes risiko konnte bisher nicht festgestellt werden. die oben erwähnten schwangerschaftskomplikationen und vorübergehenden nebenwirkungen beim neugeborenen wurden von den meisten autoren beobachtet. in der prospektiven studie von jain (2003) lebendgeborenen fanden sich vier kinder mit verschiedenen fehlbildungen (kainz 2000) . in einem retrospektiven fallbericht findet sich ein frühgeborenes zwillingspaar mit cardiomyopathie, an der eines der beiden kinder verstarb (vyas 1999). nagy (2003) berichtet über 9 u. a. mit tacrolimus exponierten schwangerschaften, darunter sind zwei kinder mit einem kleinen ventrikelseptumdefekt. hypoplastische nägel und beidseits kurze fünfte finger wurden bei einem sonst gesunden frühgeborenen nach immunsuppressiver kombinationstherapie mit tacrolimus und mmf (siehe unten) beschrieben (pergola 2001 die bisherigen erfahrungen mit ungefähr 60 mehrheitlich wegen morbus crohn behandelten schwangeren wurden retrospektiv, z. b. aus krankenakten, gewonnen (z. b. mahadevan 2005 , katz 2004 ). sie lassen kein teratogenes risiko erkennen. aus berichten über 10 schwangerschaften mit anwendung von etanercept (enbrel ® ), davon einmal bis zur 32. schwangerschaftswoche, lässt sich kein teratogenes risiko erkennen , wallace 2003 , sills 2001 . die 5 von uns prospektiv erfassten schwangerschaften mit exposition im 1. trimenon erbrachten zwei gesunde kinder, einen spontanabort und zwei schwangerschaftsabbrüche aus persönlichen gründen. zu den monoklonalen antikörpern adalimumab (humira ® ), basiliximab, (simulect ® ), daclizumab (zenapax ® ), efalizumab (raptiva ® ), muromonab-cd3 (orthoclone ® okt3), palivizumab (synagis ® ) liegen keine ausreichenden erfahrungen in der schwangerschaft vor. weitere monoklonale antikörper siehe kapitel 2.13. interferon§ -arzneimittel werden therapeutisch bei chronisch aktiver hepatitis b und c sowie bei chronisch myeloischer leukämie, haarzell-leukämie und anderen malignomen eingesetzt. hierzu zählen interferon alfa-2a (roferon ® ), interferon alfa-2b (intron a ® ), interferon alfacon-1 (inferax ® ) sowie peginterferon alfa-2a (pegasys ® ) und peginterferon alfa-2b (pegintron ® ). auch bei essentieller thrombozythämie werden interferon§ -arzneimittel verabreicht. interferon§ ist nicht plazentagängig. zahlreiche fallberichte haben bisher keine hinweise auf spezifische schädigungen der vorgeburtlichen entwicklung erbracht (übersicht bei . eine 15-jährige schwangere, die durchgängig wegen thrombozythämie interferon alfa-2a erhielt, brachte ein gesundes, wachstumsretardiertes weibliches frühgeborenes zur welt. mutter und kind zeigten klinische und laborchemische charakteristika eines (neonatalen) lupus-syndroms (fritz 2005) . interferon beta human (fiblaferon ® ) ist für schwer verlaufende viruserkrankungen zugelassen, interferon beta-1a (avonex tm , rebif ® ) und interferon beta-1b (betaferon ® ) bei multipler sklerose. boskovic (2005) führte eine kleine prospektive studie mit 23 an multipler sklerose erkrankten schwangeren durch, die g -interferon erhielten und verglich sie mit zwei kontrollgruppen, eine umfasste unbehandelte schwangere mit multipler sklerose und eine weitere gesunde schwangere. in der behandelten gruppe war die spontanabort-und totgeburtenrate erhöht. in unserer datenbank gibt es unter 27 mit interferon beta-1a exponierten schwangeren zwei spontanaborte und fünf schwangerschaftsabbrüche aus persönlichen gründen. unter 20 lebendgeborenen befand sich ein kind mit einer schweren hüftdysplasie. von 10 mit interferon beta-1b exponierten schwangerschaften endeten 3 in einem spontanabort, zwei wurden aus persönlichen gründen abgebrochen und die fünf lebend geborenen kinder waren gesund. es ist zurzeit ungeklärt, ob g -interferone ursächlich zu einer höheren abortrate führen. interferon gamma-1b (imukin ® ) wird zur verhinderung schwerwiegender infektionen bei septischer granulomatose eingesetzt. generell in dosierungen, wie sie zur therapie chronisch-entzündlicher prozesse erforderlich sind, können hydroxychloroquin und chloroquin möglicherweise abortiv wirken. im tierversuch reicherte sich chloroquin in der fetalen retina und im zns an. immer wieder wird der fall einer mutter mit lupus erythematodes zitiert, die unter dauertherapie mit chloroquin drei geschädigte und ein gesundes kind zur welt brachte. bei zwei dieser kinder wurde eine cochleovestibularisparese diagnostiziert und bei einem kind wurde im alter von 5 jahren ein wilms-tumor festgestellt (hart 1964) . dokumentierte erfahrungen zu etwa 300 schwangeren konnten jedoch kein spezifisches risiko belegen: bei 21 kindern von 15 müttern, die in der schwangerschaft wegen lupus erythematodes oder rheumatoider arthritis durchschnittlich 7 monate hoch dosiert mit hydroxychloroquin oder chloroquin behandelt wurden, waren im mittleren alter von 3 jahren keine ophthalmologischen auffälligkeiten nachweisbar (klinger 2001) . motta (2005) konnte dies bei der untersuchung weiterer 24 in schwangerschaft und stillzeit hydroxychloroquin exponierter kinder bestätigen. andere kleinere untersuchungen an insgesamt mehr als 100 erkrankten schwangeren mit systemischem lupus erythematodes (sle) oder rheumatoider arthritis geben keine hinweise auf ein teratogenes potenzial (motta 2005 , buchanan 1996 , parke 1996 . eine größere prospektive studie mit 133 schwangeren konnte im alter von durchschnittlich 2 jahren bei den 117 lebendgeborenen weder visuelle, akustische noch wachstums-oder sonstige entwicklungsdefizite finden (costedoat-chalumeu 2003) . einige autoren empfehlen ausdrücklich eine fortsetzung der therapie beim lupus erythematodes während der gesamten schwangerschaft, weil sie ein größeres risiko in einer sonst eher möglichen exazerbation der erkrankung sehen (costedoat-chalumeu 2005 , khamashta 1997 ). (pinter 2004 , rosa 1986 ); diesen stehen mehr als 100 publizierte unauffällige verläufe gegenüber (sinha 2004 , tarnacka 2000 , messner 1998 , schaefer 1994 , dupont 1991 trientin wird ebenfalls bei morbus wilson eingesetzt. bei 13 während der (gesamten) schwangerschaft behandelten frauen fanden sich keine hinweise auf spezifische auffälligkeiten im schwangerschaftsverlauf und bei den neugeborenen (eigene beobachtungen, überblick in devesa 1995) . da als nebenwirkung der behandlung häufig eine eisen-mangelanämie beobachtet wurde, wird eine therapiebegleitende eisensupplementierung empfohlen (schmidt 2003 leflunomid (arava ® ), ein pyrimidinsynthesehemmstoff, war im tierversuch bei serumkonzentrationen teratogen, die den therapeutischen werten beim menschen entsprechen. auffällig waren anophthalmie bzw. mikrophthalmie und hydrozephalus. allerdings zeigten sich gleichzeitig toxische effekte bei den muttertieren, so dass der teratogene charakter der schädigung kontrovers diskutiert wird. die halbwertszeit von leflunomid beträgt 2 wochen und länger. ausreichende erfahrungen beim menschen liegen nicht vor (brent 2001) . der autor diskutiert eine mehrtägige behandlung mit 3 x 8 g colestyramin zur verkürzung der eliminationshalbwertszeit auf etwa 1 tag, wenn der empfohlene zeitliche abstand zu einer schwangerschaft nicht eingehalten werden kann. bei der planung einer schwangerschaft wird ein therapiefreies intervall von ca. 1 monat vor konzeption empfohlen. bisher gibt es keine fallberichte, die einen teratogenen effekt beim menschen belegen. von 6 publizierten schwangerschaftverläufen wurden 2 abgebrochen, eine endete als spontanabort und 3 mit der geburt eines frühgeborenen und zweier reifgeborener kinder ohne fehlbildungen . wir beobachteten 2 gesunde kinder nach mütterlicher leflunomidexposition 4 wochen vor konzeption und 4 weitere gesunde kinder nach behandlung im 1. trimenon, davon eines nachweislich bis woche 9. zu anakinra (kineret ® ), einem anti-interleukin-1 g -therapeutikum, und abatacept (orencia ® ), einem selektiven co-stimulans-blocker bei rheumatoider arthritis, gibt es bisher keine erfahrungen in der schwangerschaft. zu ademetionin (gumbaral ® ), hyaluronsäurepräparaten (z. b. hyaject ® ) und oxaceprol (ahp 200 ® ) liegen keine systematischen untersuchungen zum nutzen und zur verträglichkeit in der schwangerschaft vor. bei 34 schwangeren mit glucosamin(dona ® )-therapie, das zur schmerzlinderung bei rheumatoider arthritis und gonarthrose eingesetzt wird, waren keine grobstrukurellen fehlbildungen nachweisbar (sivojelezova 2005) . bei 10 weiteren prospektiv nachverfolgten schwangerschaften mit exposition im 1. trimenon fanden sich ebenfalls keine anomalien (eigene daten). empfehlung für die praxis: zur antirheumatischen basistherapie (dmard) in der schwangerschaft kommt als erstes sulfasalazin infrage. azathioprin, ciclosporin, (hydroxy-)chloroquin, aber auch goldpräparate und d-penicillamin sind akzeptabel. methotrexat, leflunomid, anakinra und biologica sind kontraindiziert. nichtsteroidale antirheumatika können bis woche 30 und prednison/prednisolon in der gesamten schwangerschaft bei bedarf eingesetzt werden. soll penicillamin als chelatbildner z. b. bei morbus wilson eingesetzt werden, muss die dosis so niedrig wie möglich gewählt werden. eine begleitende gabe von kupfer in präventiver absicht wird nicht empfohlen, da allenfalls die penicillaminwirksamkeit beeinträchtigt würde. empfehlenswert ist allerdings eine ergänzende therapie mit pyridoxin (vitamin b 6 ). ob der chelatbildner trientin eine alternative für die morbus-wilson-behandlung in der schwangerschaft darstellt, kann mangels erfahrung noch nicht entschieden werden. keines der in diesem abschnitt besprochenen mittel rechtfertigt nach (versehentlicher) anwendung im 1. trimenon einen risikobegründeten schwangerschaftsabbruch (siehe kapitel 1.15). zusätzliche untersuchungen wie eine ultraschallfeindiagnostik sollten jedoch eingeplant werden. g 2.12.8 thalidomid thalidomid (ehemals contergan ® ) ist seit 1998 in den usa für die behandlung des erythema nodosum leprosum, eines schweren, entzündlichen verlaufs bei lepra, unter dem namen thalomid tm zugelassen. im rahmen des so genannten steps-programms (system for thalidomide education and prescribing safety; übersicht in neiger 2000) sollen in dieser form bisher nicht praktizierte einschränkungen und kontrollen bei verordnungsbefugten ärztinnen und patientinnen teratogene ereignisse weitgehend ausschließen. es wird jedoch befürchtet, dass dieses wirksame medikament auch (unkontrolliert) bei anderen entzündlichen und immunologischen erkrankungen eingesetzt wird, wie bei ulzerierenden hiv-assoziierten hauterkrankungen, anderen aids-begleitenden krankheiten, morbus behçet, chronischen graftversus-host-erkrankungen nach transplantation, therapierefraktären arthritiden etc. (teratology society 2000) . am teratogenen risiko der substanz hat sich seit der rücknahme vom markt in den frühen 60er jahren nichts geändert. laut einer publikation wurden 34 "contergan-kinder" in lateinamerika seit 1965 registriert, vorwiegend in solchen regionen brasiliens, in denen lepra endemisch ist. dort war das medikament weiter frei erhältlich. die dunkelziffer geschädigter kinder liegt wahrscheinlich um ein vielfaches höher (castilla 1996) . wie kürzlich vom teratologischen zentrum in porto allegre berichtet (schüler, pers. mitteilung 2006) , ist es keine ausnahme, dass frühschwangere frauen in unkenntnis des risikos das thalidomid eines an lepra erkrankten familienmitglieds für andere beschwerden einnehmen. besonders von analphabetismus betroffene familien sind mit verordnungsprotokollen wie dem oben genannten kaum zu erreichen. thalidomid kann neben der bekannten phokomelie und amelie (vorwiegend der arme) auch weniger ausgeprägte muskel-und skelett-fehlanlagen an den extremitäten verursachen. häufig wurden daumenanomalien (z. b. dreigliedrigkeit) beobachtet. außerdem sind anomalien der ohrmuschel, des gehörgangs und mittelohrs mit oder ohne taubheit möglich. ferner treten auf: hirnnervenparesen (nervus facialis), fehlbildungen am herzen und anderen organen. mentale entwicklungsauffälligkeiten, auch autismusartige symptome, abnorme tränensekretion (krokodilstränen) oder andere augenanomalien wie kolobom, glaukom, mikrophthalmie und ptosis ) sind selten. der schädigungsmechanismus des thalidomids wird bis heute diskutiert, z. b. über eine transkriptionsstörung jener gene, die die blutgefäßbildung (angiogenese) in sich entwickelnden organen steuern (stephens 2000) . auch die nachkommen von "contergan-patienten" wurden untersucht. eine hypothese besagte, dass diese ebenfalls ein höheres fehlbildungsrisiko, z. b. aufgrund einer zusätzlichen mutagenen wirkung des thalidomids, haben. diese vermutung konnte widerlegt werden (z. b. strömland 2002) . in einzelnen fällen lag offenbar eine genetisch definierte, vererbbare anomalie mit gleichem erscheinungsbild vor, die mit "contergan" verwechselt wurde. zum risiko bei einnahme des vaters siehe kapitel 1.12. empfehlung für die praxis: thalidomid ist als das für den menschen stärkste teratogen absolut kontraindiziert, wenn eine schwangerschaft nicht mit sicherheit ausgeschlossen werden kann. g 2.12.9 sonstige immunmodulatoren glatiramer (copaxone ® ) wird bei der multiplen sklerose eingesetzt. chemisch ist es ein synthetisches polypeptid aus vier aminosäuren. der hersteller berichtet, dass es auch bei einer sehr hohen dosierung keine fehlbildungen im tierversuch bei ratten und kaninchen gegeben habe. die erfahrungen beim menschen beschränken sich auf wenige unauffällige fallberichte: unter 14 lebendgeborenen fand sich kein kind mit einer fehlbildung (paulus 2005 , johnson 1995 . granulozyten-kolonien-stimulierende faktoren wie lenograstim (granocyte ® ), pegfilgrastrim (neulasta ® ) und nartograstim sind unzureichend untersucht. diese substanzen werden auch physiologisch in plazenta und dezidua gebildet und finden sich im nabelschnurblut. ein teratogenes risiko erscheint deshalb wenig wahrscheinlich. zu dem auch als immunstimulator und als hämatopoetischer wachstumsfaktor eingesetzten zytokin filgrastim (neupogen ® ) liegen erfahrungen im 2. und 3. trimenon vor (sangalli 2001) , jedoch nur wenige einzelfälle im 1. trimenon. die meisten kinder wurden gesund geboren. filgrastrim passiert die plazenta und wird in der schwangerschaft auch zur prophylaxe von neonatalen infektionen bei frühgeborenen eingesetzt (calhoun 1996) . zu inosin (isoprinosine ® ) liegen keine ausreichenden erfahrungen vor. levamisol wird als immunmodulator in kombination mit fluorouracil bei kolorektalen karzinomen gegeben oder als anthelmintikum in der tiermedizin. es bestehen ähnlichkeiten zu metronidazol. bei 11 schwangeren, davon waren 4 im 1. trimenon exponiert, gab es keine besonderheiten (2) welche konsequenzen erfordert bzw. erlaubt eine in der schwangerschaft diagnostizierte maligne erkrankung. nach heutigem wissensstand führt eine zurückliegende polychemotherapie bei einem großteil der exponierten weder zur dauerhaften infertilität, noch zu einer signifikant erhöhten abortrate oder einem geringeren geburtsgewicht bei den später entstehenden schwangerschaften (falconer 2002) . außer dauer, dosis und art der applizierten zytostatika hat das alter der frau bei der chemotherapie einen wichtigen einfluss auf die spätere fertilität (minton 2002) . eine neuere arbeit untersuchte die ovarielle funktion nach einer intensivierten therapie bei non-hodgkin-lymphomen mit cyclophosphamid, doxorubicin und vincristin (mega-chop). nur eine von 13 patientinnen, die mit 40 jahren älteste, hatte auch noch 70 monate nach therapieende eine ovarielle dysfunktion. acht patientinnen wurden schwanger und bekamen insgesamt 12 kinder. sieben frauen hatten prophylaktisch monatlich gnrh-analoga erhalten, darunter nicht die 40-jährige, jedoch 5 der frauen, die später schwanger wurden (dann 2005) . eine zurückliegende zytostatische behandlung stellt auch kein nennenswertes risiko für fehlbildungen dar. trotz des mutagenen und zytotoxischen potenzials vieler antineoplastischer substanzen sind bisher nicht vermehrt klinisch relevante chromosomenstörungen oder gendefekte beschrieben worden, so dass eine amniozentese oder chorionzottenbiopsie nicht routinemäßig durchgeführt werden muss. in einer untersuchung von etwa 2.300 schwangerschaften, bei denen der vater eine krebsbehandlung hinter sich hatte, war das geschlechtsverhältnis der kinder mit 1,0:1,03 (kontrollgruppe: 1,24:1,0) zugunsten der mädchen verändert (green 2003) . auch eine länger zurückliegende radiotherapie führt i.a. weder beim mann noch bei der frau zu bleibender infertilität, wenn ovarien bzw. testes nicht gezielt bestrahlt wurden (stovall 2004) , und hat nach heutigem kenntnisstand keine relevanten auswirkungen auf eine spätere schwangerschaft. in einer untersuchung war die wahrscheinlichkeit, kinder mit einem gewicht unter 2.500 g zu gebären etwas höher, wenn früher im bereich des beckens bestrahlt wurde (green 2002) . boice (2003) untersuchte in einer multizentrischen studie mehr als 6.000 kinder von eltern, die in ihrer kindheit mit einer radiotherapie behandelt wurden: bei 46 % der eltern betrug die gonadendosis mehr als 100 msv, bei 16 % mehr als 1.000 msv. es fanden sich keine hinweise für eine erhebliche zunahme genetischer auffälligkeiten. eine maligne erkrankung während der schwangerschaft ist mit 0,2-1 pro 1.000 schwangerschaften selten. am häufigsten treten lymphome, leukämien, brustkrebs, zervix-und ovarialkarzinome, melanome, sowie schilddrüsen-und colonkarzinome auf. es gibt keine substantiellen hinweise dafür, dass eine schwangerschaft per se die prognose beeinflusst. dies gilt auch für das mammakarzinom (merlob 2004) , das allerdings in der gravidität häufig erst in einem späteren stadium erkannt wird. abgesehen vom melanom gibt es keine fallbeschreibungen über metastasierungen der plazenta oder des fetus. wenn im 1. trimenon eine maligne erkrankung diagnostiziert wird, entscheiden sich viele paare aufgrund des potenziellen teratogenen risikos der zu erwartenden therapie für einen abbruch der schwangerschaft, so dass hierüber die wenigsten erfahrungen vorliegen. die dokumentierten fälle zeigen jedoch, dass fehlbildungen keineswegs obligatorisch auftreten. eine polychemotherapie im 2. oder 3. trimenon kann je nach substanz und verabreichter dosis zu fetaler wachstumsverzögerung und/oder zur passageren knochenmarksdepression mit fetaler anämie, leukopenie und thrombozytopenie führen. ein intrauteriner fruchttod wurde nur selten beschrieben. überraschenderweise wird die chemotherapie vom fetus meistens ohne bleibende schäden toleriert. bisher konnte auch keine beeinträchtigung der intellektuellen entwicklung festgestellt werden (nulman 2001) . im 3. trimenon wird häufig eine vorzeitige entbindung diskutiert, um dann "freie hand" für die therapie zu haben und den fetus nicht weiter mit potenziell toxischen substanzen zu belasten. empfehlung für die praxis: im allgemeinen wird eine frist von 2 jahren bei der frau und von sechs monaten beim mann nach einer antineoplastischen therapie empfohlen. sollte vorher eine schwangerschaft eintreten, ist dies kein grund, eine intakte und gewollte schwangerschaft abzubrechen. eine maligne erkrankung während einer schwangerschaft ist selten und erfordert größtmögliche interdisziplinäre fachärztliche und psychosoziale unterstützung. die entscheidung eines paares über eine antineoplastische therapie in der schwangerschaft sollte nach sorgfältiger aufklärung über die jeweiligen risiken von ärztlicher seite mitgetragen werden. jede krebserkrankung in der schwangerschaft verlangt eine individuelle beratung und behandlung. in der regel werden neoplastische erkrankungen heute nach optimierten therapieschemata behandelt, die auch in der schwangerschaft beibehalten werden sollten, um der schwangeren bestmögliche chancen für ihr überleben zu gewährleisten. deshalb werden in diesem abschnitt im gegensatz zu den übrigen kapiteln keine therapievorschläge aus embryonaltoxikologischer perspektive gegeben. hoch auflösende ultraschalldiagnostik sollte diesen frauen zur bestätigung einer normalen entwicklung des fetus angeboten werden. (mulvihill 1987) . beschrieben wird auch der spontanabort eines männlichen fetus in schwangerschaftswoche 24 mit jeweils nur 4 zehen und einer syndaktylie (garrett 1974) , sowie ein 1.900 g schweres neugeborenes, das einen vorhofseptumdefekt hatte und an einem atemnotsyndrom starb (thomas 1976 schardein 2000 und www.motherisk.org) . publiziert wurden jedoch auch ein abortierter fetus mit nierenagenesie nach einer kombinationstherapie (mennuti 1975) , ein 1.900 g schweres neugeborenes mit vorhofseptumdefekt, das an einem atemnotsyndrom starb und dessen mutter mit vincristin und vinblastin behandelt worden war (thomas 1976) , ein kind mit gaumenspalte nach vincristin bis woche 6, gefolgt von vinblastin und anderen zytostatika (mulvihill 1987) sowie eine frau mit einer kombinationstherapie wegen morbus hodgkin im 1. trimenon, deren kind mit hydrozephalus vier stunden nach geburt verstarb (zemlicki 1992) . ferner gibt es berichte zu unauffälligen schwangerschaften nach exposition im 2. und/oder 3. trimenon, jedoch auch über eine neonatale panzytopenie (pizzuto 1980 ) und intrauterine wachstumsretardierung. drei kinder, deren mütter wegen brustkrebs im 2. bzw. 3. trimenon mit vinorelbin (navelbine ® ) plus 5-fluorouracil behandelt wurden, waren im alter von 2 bzw. 3 jahren normal entwickelt (cuvier 1997 rodriguez 1995 , horbelt 1994 , arango 1994 , brunet 1993 vor, darunter auch 2 mit exposition im 1. trimenon (aviles 1991) , bei denen gesunde kinder zur welt kamen. die weitere entwicklung dieser beiden kinder verlief bis zum alter von 3 bzw. 8 jahren normal. bei der exposition im 2./3. trimenon wurde bei einigen kindern eine vorübergehende panzytopenie beschrieben (hsu 1995 , murray 1994 (elit 1999) . ein anderes frühgeborenes der schwangerschaftswoche 27, dessen mutter eine polychemotherapie in woche 26 erhielt, zeigte ab dem 3. lebenstag eine schwere leukopenie und anämie und verlor ab dem 10. lebenstag kopf-und lanugobehaarung. nach 12 wochen erholte sich das haarwachstum. eine nachuntersuchung nach einem jahr zeigte bis auf einen moderaten beidseitigen hörverlust (sensorineural) eine normale entwicklung (raffles 1989) . teniposid (vm 26-bristol ® ) ist ein semisynthetisches derivat des podophyllotoxins. es hemmt die topo-isomerase, verhindert die dna-synthese und die zelltransformation in die prophase. nur ein fallbericht zu einem gesunden neugeborenen liegt vor, bei dem die mutter während des 2. trimenons gleichzeitig mit anderen chemotherapeutika behandelt worden war (lowenthal 1982 (steege 1980 , shotton 1963 , wobei einer einen offenbar gesunden zwilling hatte. der dritte fetus zeigte retinale defekte (rugh 1965) . auch berichte mit unauffälligem schwangerschaftsausgang liegen vor (jacobs 1981) . cyclophosphamid (endoxan ® ) ist eine alkylierende substanz, die man zur behandlung einer vielzahl von malignen erkrankungen und bei autoimmunerkrankungen, wie z. b. dem systemischen lupus erythematodes, einsetzt. tierexperimente bei ratten, mäusen, kaninchen, affen und hühnern führten zu zns-, kraniofazialen und skelettfehlbildungen (zitiert nach enns 1999) . die erfahrungen zur behandlung schwangerer mit cyclophosphamid im 1. trimenon beruhen auf einer kleinen fallserie (aviles 1991) und auf retrospektiven kasuistiken. insgesamt gibt es berichte über mehr als 30 im 1. trimenon behandelte frauen, darunter eine zwillingsschwangerschaft: 16 kinder waren gesund (peres 2001 , aviles 1991 , pizzuto 1980 , 11 feten bzw. kinder hatten große oder kleine fehlbildungen (paskulin 2005 , paladini 2004 , vaux 2003 , giannakopoulou 2000 , enns 1999 , mutchinick 1992 , kirshon 1988 , murray 1984 , toledo 1971 , greenberg 1964 , zwei schwangerschaften endeten als spontanabort (clowse 2005) und bei weiteren 2 kam es in woche 25/26 zum fruchttod (peres 2001 , ba-thike 1990 . ein weiterer junge wurde mit multiplen fehlbildungen geboren und entwickelte mit 11 jahren ein schilddrüsenkarzinom, mit 14 ein neuroblastom und im alter von 16 jahren wurde ein metastasiertes papilläres schilddrüsenkarzinom diagnostiziert. seine zwillingsschwester war gesund (zemlickis 1993) . wir konnten bisher 5 im 1. trimenon exponierte schwangerschaften prospektiv auswerten, davon endete eine als spontanabort, eine wurde im 2. trimenon trotz unauffälligem hoch auflösendem ultraschallbefund aus mütterlicher indikation abgebrochen, und es wurden drei gesunde kinder geboren. neuerdings wird eine cyclophosphamid-embryopathie (enns 1999) bzw. eine cyclophosphamid-methotrexat-cytarabin-embryopathie (vaux 2003) diskutiert: kennzeichen sind zns-auffälligkeiten, faziale dysmorphien, distale extremitätenreduktionsdefekte sowie augenund ohrfehlbildungen und eine wachstumsretardierung. neun der oben genannten fallbeschreibungen entsprechen zumindest teilweise diesem muster, darunter auch solche, bei denen die mütter im rahmen eines systemischen lupus erythematodes als einziges zytostatikum cyclophosphamid erhalten hatten. durch therapie mit cyclophosphamid im 2. und 3. trimenon kann eine panzytopenie und ein verringertes geburtsgewicht beim neugeborenen verursacht werden. auch frühgeburten treten häufiger auf (kerr 2005) . zahlreiche fallbeschreibungen schildern einen unauffälligen ausgang der schwangerschaft, auch bei malignen erkrankungen (ring 2005 , köseoglu 2001 , luisiri 1997 , oates 1990 ). bei zwei lupus-patientinnen, die wegen der schwere der erkrankung im 2. trimenon cyclophosphamid erhielten, endete die schwangerschaft mit spätabort (clowse 2005) . ifosfamid (z. b. holoxan ® ) und trofosfamid (ixoten ® ) sind dem cyclophosphamid strukturell ähnlich. es gibt einen fallbericht über ein gesundes kind, dessen mutter wegen ewing-sarkom des beckens im 3. trimenon u. a. mit ifosfamid behandelt wurde (merimsky 1999) . chromosomale anomalien und malignomentstehung wurden bei nicht schwangeren patienten beobachtet, die mit melphalan (alkeran ® ) behandelt worden waren. entsprechende auswirkungen bei pränatal exponierten kindern sind nicht bekannt. zur anwendung in der schwangerschaft liegt lediglich ein bericht über eine fehlgeburt unter monotherapie im 1. trimenon vor (zemlickis 1992) . zu bendamustin (ribamustin ® ) wird über ein gesundes kind berichtet, dessen mutter im 1. trimenon behandelt worden war . zu estramustin (z. b. cellmustin ® ) liegen keine erfahrungen in der schwangerschaft vor. g 2.13.7 andere alkylanzien busulfan (z. b. myleran ® ) wirkt speziell auf das knochenmark alkylierend und wird deshalb bei leukämien und bei der vorbereitung zur knochenmarktransplantation eingesetzt. mindestens 49 schwangerschaften, darunter 31 mit anwendung im 1. trimenon wurden publiziert, von denen wiesen 6 kinder bzw. feten unterschiedliche fehlbildungen auf . vier von 12 mit dacarbazin (detimedac ® ) behandelte schwangere waren im 1. trimenon exponiert. alle neugeborenen waren unauffällig (dipaola 1997 , aviles 1991 . in 4 von 12 fallberichten mit einer mechlorethamin-therapie im 1. trimenon (zusammen mit anderen zytotoxischen substanzen) wurden folgende anomalien beschrieben: oligodaktylie, hirnblutungen, hydrozephalus und nierenanomalien (zemlickis 1992 , mennuti 1975 . in 4 fällen kam es zum abort und zweimal zum schwangerschaftsabbruch, andere schwangerschaften verliefen unauffällig (aviles 1991) . procarbazin (natulan ® ) ist bestandteil einer kombinationstherapie bei morbus hodgkin und anderen lymphomen. von 10 im 1. trimenon exponierten neugeborenen waren lediglich 3 gesund (aviles 1991 , schapira 1984 . folgende anomalien wurden beschrieben: multiple hämangiome, nieren-und extremitätenanomalien, lippen-, kiefer-, gaumen-spalten, vorhofseptumdefekt sowie intrauterine wachstumsretardierung. eine frau, die 30 tage lang versehentlich 50 mg täglich im 2. trimenon einnahm, wurde von einem gesunden kind entbunden (daw 1970 in der übersicht von werden 29 schwangere beschrieben, vier davon waren im 1. trimenon exponiert (feliu 1988 , alegre 1982 . die 22 lebend geborenen kinder wiesen keine fehlbildungen auf. bei 2 dieser kinder kam es im alter von 2 monaten zur vorübergehenden neutropenie. nachfolgeuntersuchungen an 13 kindern dieser gruppe im alter zwischen 6 monaten und 9 jahren zeigten eine normale entwicklung. zuazu (1991) (garcia 1981 , blatt 1980 , hassenstein 1978 . ein kind, dessen mutter gleichzeitig cyclophosphamid und eine kobaltbestrahlung der linken axilla und supraklavikularregion von woche 8-13 erhalten hatte, wies eine anal-atresie mit rektovaginaler fistel auf (murray 1984) . kim (1996) ein fallbericht (nakajima 2004 ) zeigte erneut, dass eine zytostatische therapie (doxorubicin und ifosfamid) im 2./3. trimenon zu gesunden, aber wachstumsretardierten kindern führen kann. bei doxorubicin sind jedoch kardiotoxische nebenwirkungen bekannt: drei fallberichte über junge schwangere, die in ihrer kindheit bzw. jugend doxorubicin erhalten hatten und kardial unauffällig waren, dekompensierten am ende der schwangerschaft (pan 2002) . zu epirubicin (z. b. farmorubicin ® ) liegen mindestens 20 fallberichte über kombinationstherapien vor, davon 2 expositionen im 1. trimenon, die mit spontanabort endeten. bei den übrigen schwangerschaften gab es einen abort, eine totgeburt und ein kind starb kurz nach der geburt. beschrieben wurden ferner intrauterine wachstumsretardierung, frühgeburten und eine vorübergehende leukopenie (ring 2005 , gadducci 2003 , giacalone 1999 , müller 1996 , goldwasser 1995 . der plazentare übergang von epirubicin ist gering und liegt etwas über dem von doxorubicin (gaillard 1995) . fünf falldokumentationen berichten über eine kombinationstherapie mit idarubicin (zavedos ® ) nach dem 1. trimenon (claahsen 1998 , reynoso 1994 . im ersten fall kam es nach therapiebeginn zum intrauterinen fruchttod, im zweiten wurde ein wachstumsretardiertes, im übrigen aber gesundes neugeborenes beschrieben. das dritte kind wurde in woche 28 geboren und fiel mit einer drei tage andauernden reversiblen herzinsuffizienz auf, die von den autoren auf idarubicin zurückgeführt wurde (achtari 2000) . in 2 weiteren fallberichten wird von einer reversiblen rechtsherzvergrößerung beim kind berichtet (niedermeier 2005 , siu 2002 ). in einem dieser beiden fälle wurden außerdem ein ventrikelseptumdefekt, kurze finger mit dysplastischen nägeln, kurze extremitäten und faziale auffälligkeiten diagnostiziert, die sich mit der ausschließlich im 2. und 3. trimenon erfolgten exposition mit idarubicin und cytarabin nicht erklären lassen (niedermeier 2005) . idarubicin hat zwar eine geringere kardiotoxizität als die traditionellen anthrazykline, die größere lipophilie begünstigt jedoch den plazentaren übergang. dies könnte erklären, warum es in den wenigen fallbeschreibungen so häufig zu kardialen komplikationen beim fetus kam. zu mitoxantron (z. b. onkotrone ® ) liegen 4 fallbeschreibungen vor. die eine betrifft eine kombinationsbehandlung u. a. mit idarubicin, mit folgendem fruchttod (reynoso 1994) . außerdem wurde ein unauffälliges neugeborenes nach polychemotherapie in woche 24-34 beobachtet (azuno 1995) sowie ein gesundes und ein wachstumsretardiertes kind nach therapie im 2. trimenon (giacalone 1999) . mitoxantron besitzt immunmodulatorische eigenschaften und wird bei bestimmten formen der multiplen sklerose eingesetzt. zur behandlung schwangerer mit aclarubicin und pirarubicin liegen keine informationen vor. g 2.13.9 andere zytotoxische antibiotika bleomycin (z. b. bleo-cell ® ) ist ein zytotoxisches glycopeptid-antibiotikum, das mit anderen chemotherapeutika bei morbus hodgkin, non-hodgkin-lymphomen und teratomen eingesetzt wird. es zeigten sich weder fetopathien noch chromosomenstörungen (lowenthal 1982) . ein kind, dessen mutter außerdem mit etoposid und cisplatin bis eine woche vor der entbindung behandelt worden war, wies eine neutropenie und leukopenie auf (raffles 1989) . zwei andere kinder, die den gleichen substanzen im 2./3. trimenon ausgesetzt waren, waren unauffällig (han 2005). weitere 22 kinder, darunter 11 mit beginn der polychemotherapie im 1. trimenon, zeigten ebenfalls keine anomalien (aviles 1991) . unauffällig waren auch 6 kinder, die im 2. und 3. trimenon mit dactinomycin (lyovac-cosmegen ® ) exponiert waren . zu mitomycin (z. b. mito-medac ® ) gibt es keine erfahrungen in der schwangerschaft. g 2.13.10 folsäure-analoge antimetabolite (folsäure-antagonisten) aminopterin nach behandlung mit aminopterin, einer dem methotrexat verwandten substanz, wurden schon in den 50er jahren fehlbildungen beschrieben (warkany 1959 , meltzer 1956 , thiersch 1952 methotrexat (ein methylderivat des aminopterins, im englischen auch amethopterin genannt; z. b. mtx hexal ® ) hat zwar nur eine halbwertszeit von 12-24 stunden, aber ca. 5-35 % werden als polyglutamat-derivat in hepatozyten und erythrozyten über mehrere monate gespeichert (hendel 1984) . es wird bei einem breitem spektrum von indikationen eingesetzt: zur beendigung von ektopen oder unerwünschten schwangerschaften, bei autoimmunerkrankungen, bei chronisch entzündlichen krankheiten und zur behandlung von neoplasien. methotrexat besitzt ein teratogenes risiko mit einem ähnlichen muster an fehlbildungen wie aminopterin (siehe oben), so dass verschiedentlich von einem aminopterin/methotrexat-syndrom gesprochen wird (bawle 1998) . betrachtet man die übereinstimmung der bei methotrexat, cyclophosphamid und cytarabin beschriebenen fehlbildungen (siehe unter cyclophosphamid 2.13.6), dann scheint der begriff aminopterin/methotrexat-embryopathie nicht gerechtfertigt. ob diese arzneimittel einen gemeinsamen embryotoxischen wirkungsmechanismus besitzen, wie vaux (2003) vermutet, ist unklar. ob noch weitere antimetabolite vergleichbare fehlbildungen hervorrufen, ist derzeit nicht zu beurteilen. in über 30 veröffentlichungen fanden sich mehr als 200 im 1. trimenon behandelte schwangere. da es sich in der regel um retrospektive fallberichte handelt und nicht um eine prospektive studie, verbieten sich berechnungen eines fehlbildungsrisikos. bei einigen dieser publikationen fehlen zudem angaben zur dosis und indikation, wie z. b. bei mcelhatton (2000) , die über 82 exponierte feten berichtet, davon 53 im 1. trimenon. zwölf feten mit nicht genanntem expositionszeitraum waren auffällig, darunter 9 schädelanomalien und 6 andere skelettfehlbildungen. im folgenden werden nur die arbeiten mit genaueren angaben vorgestellt. zehn veröffentlichungen beschreiben schwangere, die im rahmen einer polychemotherapie im 1. trimenon methotrexat erhalten hatten. interessanterweise fanden sich in dieser hochrisikogruppe 16 gesunde kinder (zemlickis 1992 , aviles 1991 , feliu 1988 , dara 1981 , pizzuto 1980 , ein kind mit einer inguinalhernie (giannakopulou 2000) , ein spontanabort (giacalone 1999) , eine totgeburt ohne fehlbildungen (peres 2001) (z. b. seidahmed 2006 , milunsky 1968 ). die gesamtdosis lag zwischen 10 und 100 mg methotrexat. in 7 dieser schwangerschaften (8 kinder) wurde zusätzlich misoprostol (yedlinski 2005 , adam 2003 , wheeler 2002 einige tage nach methotrexat verabreicht. in einem fall wurde zuvor erfolglos eine kürettage durchgeführt (bawle 1998) . andere berichte thematisieren pränatal diagnostizierte schädigungen exponierter feten, die zum abbruch der schwangerschaft führen (chapa 2003 , krähenmann 2002 . antirheumatische therapie mit mtx. zehn veröffentlichungen mit mehr als 110 im 1. trimenon exponierten schwangerschaften beziehen sich auf die als "low-dose" bezeichnete therapie bei erkrankungen aus dem rheumatischen formenkreis. doch abgesehen von der kürzlich veröffentlichten kleinen prospektiven studie aus frankreich (lewden 2004 ) und unseren eigenen noch unveröffentlichten daten handelt es sich um retrospektive fallbeschreibungen oder allenfalls um kleine prospektive fallserien mit maximal 4 schwangerschaften (østensen 2000 (østensen , donnenfeld 1994 . insgesamt fanden sich 4 kinder mit typischen fehlbildungen, von denen allerdings zwei mütter (del campo 1999 , powell 1971 ) mit 3 × 12,5 mg/woche (bis woche 10) bzw. 5 mg/tag (bis woche 8) mehr mtx einnahmen als bei "low-dose" (maximal 25 mg/woche) üblich ist. eine weitere erhielt 7,5 mg/tag für zwei tage in woche 6 (nguyen 2002) und die vierte schwangere 12,5 mg/woche bis woche 10 in kombination mit täglich 1 mg folsäure (buckley 1997) . dem stehen fallbeschreibungen mit 14 gesunden kindern mit einer dosis zwischen 7,5 und 15 mg/woche gegenüber (østensen 2000 , donnenfeld 1994 , feldkamp 1993 , kozlowski 1990 ), 4 spontanaborte (østensen 2000 (østensen , kozlowski 1990 ) und 2 schwangerschaftsabbrüche ohne embryopathischen hintergrund. berichtet über 38 retrospektive schwangerschaften unter "low-dose"-mtx, wobei genauer einnahmezeitraum und dosis nicht bekannt sind. es kamen 21 gesunde kinder zur welt, bei 3 schwangerschaften wurden fehlbildungen beschrieben keine spezifizierung, 7 endeten als spontanabort und 8 schwangerschaftsabbrüche wurden durchgeführt. in einer prospektiven französischen studie (lewden 2004 ) mit 28 fällen und einer wöchentlichen mittleren mtx-dosis von 10,5 mg wurden 4 spontanaborte, 5 schwangerschaftsabbrüche und 19 lebendgeburten registriert, darunter keine mtx-embryopathie. diese erfahrungen decken sich mit unseren eigenen: von 22 prospektiv dokumentierten im 1. trimenon exponierten schwangerschaften (wöchentliche dosis 10 bis 25 mg mtx) wurden 3 bei unauffälligem ultraschallbefund abgebrochen, 5 endeten als spontanabort und 13 mit der geburt eines gesunden kindes (1 frühgeborenes mit 36 wochen). ein kind, dessen mutter zusätzlich phenprocoumon und andere medikamente einnahm, war mit 1.600 g am geburtstermin wachstumsretardiert, wies eine inguinalhernie auf und war 14 tage lang hyperirritabel. bei kindern mit typischen fehlbildungen scheint eine begleitende kleinwüchsigkeit bestehen zu bleiben. in der weiteren entwicklung wurden sowohl eine normale intelligenzentwicklung als auch mentale retardierung beobachtet. die dosierungsbereiche für mtx bei polychemotherapie, abortversuch und bei rheumatischen indikationen ("low-dose") überschneiden sich. daher ist die schlussfolgerung, es gibt für mtx sichere und riskante indikationen, unzulässig. zwar fand sich bei 10 mg wöchentlich bisher nur ein fallbericht mit verdächtiger symptomatik, so dass die von feldkamp (1993) geäußerte these plausibel erscheint, dass mtx erst ab einer wöchentlichen dosis von 10 mg teratogen wirkt. die autorin postuliert ferner eine sensible phase zwischen woche 8 und 10. für eine definitive schlussfolgerung sind die vorliegenden daten jedoch noch unzureichend. empfehlung für die praxis: nach behandlung mit dem teratogenen methotrexat wurden bei einer reihe von schwangerschaften entwicklungsanomalien beobachtet, die im wesentlichen aus einer pränatal beginnenden wachstumsretardierung, einem schweren ossifikationsdefekt des calvariums, fazialen dysmorphien, zns-störungen mit oder ohne intelligenzminderung und extremitätendefekten bestehen. eine unbedenkliche dosis kann nicht angegeben werden, allerdings gibt es bisher keine hinweise auf teratogene effekte unterhalb einer wöchentlichen dosis von 10 mg. eine (versehentlich) ins 1. trimenon hinein weiter geführte antirheumatische "low-dose"-therapie scheint nur ein gering erhöhtes fehlbildungsrisiko zu besitzen. generell sind bei einer exposition im 1. trimenon fehlbildungen keineswegs obligat, auch nicht bei der behandlung von bösartigen erkrankungen. dass kinderwunschpatientinnen nach einer (antirheumatischen) methotrexat-therapie mindestens 3 monate pause bis zur konzeption einhalten, kann mit den jetzt vorliegenden daten nicht begründet werden. jeder schwangeren, die im 1. trimenon mit mtx exponiert war, sollte eine hoch auflösende ultraschalldiagnostik zur bestätigung einer normalen entwicklung des fetus angeboten werden. g 2.13.11 purin-analoge antimetabolite (purin-antagonisten) 6-mercaptopurin (6-mp; puri-nethol ® ) ist ein purin-analogon, das über eine hemmung der nukleinsäuresynthese wirkt (siehe auch azathioprin = aza, prodrug von 6-mp). es wurde bisher kein spezifisches fehlbildungssyndrom beschrieben. 6-mp wird auch als immunsuppressivum eingesetzt, z. b. bei chronisch entzündlichen darmerkrankungen ("inflammatory bowel disease" = ibd). auch wenn die plasma-hwz von 6-mp und aza mit 1-3 stunden sehr kurz ist, beträgt die halbwertszeit des zytostatisch aktiven metaboliten, der tioguanin-nukleotide, 3 bis 13 tage. wirkungsweise und metabolisierung von 6-mp sind interindividuell variabel. dabei spielt die thiopurin-methyltransferase (tpmt) eine rolle, deren aktivität genetisch determiniert ist. aza und 6-mp können die plazenta passieren . von mehr als 100 im 1. trimenon exponierten schwangeren nahmen über 60 das 6-mp im rahmen einer ibd ein , häufig in kombination mit prednisolon und eine kleine gruppe sogar fortlaufend während der gesamten schwangerschaft. die meisten kinder der mit 6-mp therapierten schwangeren in dieser und anderen publikationen wurden ohne anomalien geboren , aviles 1990 , dara 1981 , pizzuto 1980 . einige kinder bzw. feten wiesen fehlbildungen auf, wie z. b. polydaktylie (mulvihill 1987) , hypospadie (sosa 1983), hydrozephalus , lungenhypoplasie, sowie harnblasen-und urethrafehlbildungen , gaumenspalte und gesichtsdysmorphien (tegay 2002) . ein nennenswertes teratogenes potenzial lässt sich aus diesen berichten nicht ableiten. die dosierungsbereiche bei den beiden wichtigsten behandlungsindikationen ibd und leukämie überschneiden sich. daher ist die indikation primär kein unterscheidungsmerkmal hinsichtlich potentieller teratogenität. tioguanin (thioguanin-gsk ® ) ist ein purin-analogon, das dna-brüche in säugetierzellen verursacht. es ist dem 6-mp hinsichtlich struktur, wirkungsweise, nebenwirkungen und interaktionen ähnlich. bei 5 im 1. trimenon behandelten schwangeren fand sich kein auffälliges neugeborenes (übersicht in . eine weitere kasuistik beschreibt 1 kind mit kraniosynostose, fingeranomalien und radiusaplasie, dessen mutter in woche 8 gleichzeitig auch mit cytarabin, das vermutlich die fehlbildungen verursacht hat, behandelt wurde (schafer 1981) . auch artlich (1994) berichtet über 1 fehlgebildetes kind nach exposition im 1. trimenon (siehe unter cytarabin). das kind einer wegen haarzell-leukämie bis woche 10 mit cladribin (z. b.leustatin ® ) behandelten schwangeren zeigte keine teratogenen effekte (alothman 1994) . zu fludarabin (fludara ® ) gibt es bisher keine informationen. (aviles 1991 (aviles & 1990 , ein spontanabort ereignete sich 20 tage nach ende der zytostase (zuazu 1991) , zwei schwangerschaftsabbrüche wurden registriert, einer davon mit 20 wochen und unauffälligem befund beim fetus (zemlickis 1992 , lilleyman 1977 . drei kinder wiesen extremitätenanomalien auf, eines von ihnen hatte zusätzlich eine bilaterale mikrotie und atresie des äußeren gehörgangs (wagner 1980 (peres 2001 , veneri 1996 , requena 1995 , aviles 1991 und 1990 , blatt 1980 . auch über 3 spätaborte bzw. totgeburten wurde berichtet (greenlund 2001 , zitiert nach zuazu 1991 , des weiteren über 3 frühgeborene mit schwerer, aber reversibler panzytopenie (hsu 1995 , murray 1994 , engert 1990 ). reynoso (1987) berichtet über 3 gesunde kinder und ein frühgeborenes der schwangerschaftswoche 29, dessen mutter wegen aml ab schwangerschaftswoche 25 zytostatisch behandelt wurde. im alter von 2 jahren wurde eine angeborene adhärenz der iris an der kornea des linken auges diagnostiziert. bis zum 3. lebensjahr entwickelte sich der junge im übrigen unauffällig. 5-fluorouracil (5-fu; z. b. 5-fu hexal ® ) greift durch verdrängen von uracil ebenfalls in die dna-und rna-synthese ein. zur lokalen vaginalen anwendung von 5-fluorouracil im 1. trimenon liegen berichte über fünf gesunde kinder vor ). kasuistiken zur anwendung im 1. trimenon zusammen mit anderen chemotherapeutika beschreiben 4 gesunde kinder , peres 2001 , zemlicki 1992 , zwei spontanaborte (giacalone 1999) und eine komplexe fehlbildung nach exposition in woche 11 und 12 (stephens 1980) . paskulin (2005) beschreibt ein kind, das intrauterin bis woche 16 mit cyclophosphamid, fluorouracil und doxorubicin exponiert war und mit wachstumsretardierung, fazialen dysmorphien und verschiedenen distalen extremitätenfehlbildungen geboren wurde. die meisten der mehr als 40 kinder mit intrauteriner 5-fu-exposition im 2. und 3. trimenon waren gesund (ginopoulos 2004 , berry 1999 . selten wurde eine intrauterine wachstumsretardierung beschrieben (zemlickis 1992) . dreicer (1991) berichtet über einen jungen, der im 2./3. trimenon hohen dosen 5-fu ausgesetzt war (insgesamt 20 g), bei der geburt in schwangerschaftswoche 38 mit 2.660 g ein unterdurchschnittliches gewicht aufwies und im alter von zwei jahren normal entwickelt war. zur topischen anwendung von fluorouracil siehe abschnitt 2.17. zu gemcitabin (gemzar ® ) und capecitabin (xeloda ® ) gibt es keine informationen zur verträglichkeit in der schwangerschaft. g 2.13.13 taxane taxane wirken antineoplastisch über eine hemmung der synthese der mikrotubuli. sie werden beim mammakarzinom eingesetzt. erfahrungen zur anwendung im 1. trimenon liegen nicht vor. sechs kasuistiken zur exposition mit paclitaxel (taxol ® ) im 2./3. trimenon berichten über gesunde kinder (v.a. gonzales-angulo 2004 , cardonick 2004 , gaducci 2003 , mendez 2003 , sood 2001 (raffles 1989) . elit (1999) berichtete über ein mit bleomycin, cisplatin und etoposid exponiertes kind, das bis zum alter von 16 monaten untersucht wurde. dabei bestätigte sich die bereits intrauterin abzeichnende ventrikulomegalie, die zu einer hirnatrophie geführt hatte. in einer fallserie von peres (2001) wird über eine totgeburt mit 26 schwangerschaftswochen ohne fehlbildungen berichtet. die mutter hatte wegen eines non-hodgkin-lymphoms cisplatin und etoposid in woche 22 erhalten. außer der in 2 fällen beschriebenen intrauterinen wachstumsretardierung waren die übrigen kinder gesund (ohara 2000 , dipaola 1997 , giacalone 1996 , hoffmann 1995 . ob die tierexperimentell beobachtete erhöhte rate an tumoren, z. b. der haut, nach pränataler exposition mit cisplatin für den menschen relevant ist, kann nicht beurteilt werden. carboplatin (z. b. ribocarbo ® ) ist dem cisplatin verwandt. fetotoxische wirkungen wurden bei einer zwischen woche 17 und 33 behandelten schwangeren nicht beobachtet (mendez 2003 (consoli 2004 , carradice 2002 , fadilah 2001 . ein weibliches reifgeborenes, das intrauterin ab woche 15 mit atra und idarubicin exponiert war, wies einen vorhofseptumdefekt und eine milde rechtsventrikuläre dilatative kardiomyopathie auf, die sich nach ein bis zwei monaten vollständig zurückbildete. der hämodynamisch unbedeutende vorhofseptumdefekt war weiter nachweisbar (siu 2002) . zu amsacrin (amsidyl ® ), miltefosin (miltex ® ), das auch bei leishmaniose eingesetzt wird, sowie zu pentostatin (nipent ® ) und mitoguazon gibt es keine informationen zur verträglichkeit in der schwangerschaft. gleiches gilt für die topo-isomerase-inhibitoren irinotecan (campto ® ) und topotecan (hycamtin ® ), sowie für die photosensitizer temoporfin (foscan ® ) und porfimer-natrium (photofrin ® ) und für bexaroten (targretin ® ), einem agonisten am retinoid-x-rezeptor. auch zu pemetrexed. (alimta ® ), einem thymidylat-synthese-inhibitor, und zu mitotan (lysodren ® ) liegen keine erfahrungen in der schwangerschaft vor. imatinib, ein protein-tyrosinkinase-inhibitor (glivec ® ) wird u. a. zur therapie der chronisch myeloischen leukämie eingesetzt. wenige fallberichte existieren zur anwendung in der schwangerschaft. eine 44-jährige gebar ein gesundes 3.200 g schweres mädchen, das intrauterin bis woche 8 mit imatinib exponiert war (ali 2005) . hensley (2003) beschreibt einen jungen mit hypospadie und zwei schwangerschaftsabbrüche wegen fehlbildungen der feten (hydrozephalus, herzfehler). in einem weiteren fallbericht mit imatinib-exposition bis woche 7 geht es um ein mädchen mit pylorusstenose (heartin 2004) . erlotinib (tarceva ® ) ist ein neu zugelassenes zytostatikum zur behandlung des nicht-kleinzelligen lungenkarzinoms. erfahrungen zur schwangerschaft liegen nicht vor. g 2.13.16 weitere antineoplastisch wirkende enzyme und antikörper asparaginase (asparaginase ® ) ist ein pflanzliches enzym, das die verfügbarkeit der aminosäure asparagin für das tumorwachstum reduziert. es wird mit anderen chemotherapeutika bei akuter leukämie kombiniert. bei 7 im 2. trimenon exponierten kindern fanden sich keine fehlbildungen, 2 kinder wiesen jedoch eine knochenmarkhypoplasie auf und 1 kind chromosomenanomalien (turchi 1988 , scheuning 1987 . alemtuzumab (mabcampath ® ), ibritumomab-tiuxetan (zevalin ® ), cetuximab (erbitux ® ), edrecolomab und bortezomib (velcade ® ) und tositumomab (bexxar ® ) sind monoklonale antikörper, für die es keine erfahrungen zur verträglichkeit in der schwangerschaft gibt. zu rituximab (mabthera ® ) liegen 3 erfahrungsberichte mit unauffälligem schwangerschaftsausgang vor. zwei behandlungen fanden aus versehen im 1. trimenon statt, die andere ab woche 21 (ojeda-uribe 2006, kimby 2004 , herold 2001 . trastuzumab (herceptin ® ) ist ein monoklonaler antikörper, der das "human epidermal growth factor receptor 2"-protein blockiert und eine geschätzte hwz von 12 tagen hat. es gibt einen fallbericht über eine versehentliche exposition einer 28-jährigen mit brustkrebs, die bis woche 20 alle drei wochen das medikament bekam. als in woche 23 die schwangerschaft bemerkt wurde, zeigte sich ein anhydramnion bei einem gesunden weiblichen fetus. allmählich regenerierte sich die fruchtwassermenge. in woche 37 wurde ein gesundes mädchen entbunden, das auch im alter von 6 monaten eine normale nierenfunktion zeigte und keinen anhalt für eine pulmonale hypoplasie aufwies (watson 2005) . noch in der erprobung ist gefitinib beim kleinzelligen bronchialkarzinom, zu dem es noch keine erfahrungen in der schwangerschaft gibt. gleiches gilt für lapatinib und für bevacizumab (avastin ® ), das zusammen mit 5-fluorouracil beim metastasierten colon-oder rektumkarzinom angewendet wird. aldesleukin ( (cullins 1994) und ein weibliches neugeborenes mit indifferenter genitalentwicklung (tewari 1997) . bei einem mädchen, dessen mutter bis zum 4. schwangerschaftsmonat tamoxifen nahm, wurde im alter von 2 jahren ein adenom der vagina diagnostiziert. auch über unauffällige verläufe wird berichtet , isaacs 2001 , lai 1994 (bond 1994) . fallbeschreibungen über fehlgeschlagene abortversuche und überdosierungen unter der geburt beschreiben derartige seltene vorkommnisse. eine untersuchung in brasilien spricht für eine kausale beziehung zwischen fehlgeschlagenem abortversuch mit dem auch als ulkusmittel verwendeten misoprostol (cytotec ® ) und einer in wenigen fällen beobachteten möbius-sequenz (u. a. hirnnervenaplasie und extremitätendefekte) bei den kindern. auch andere fehlbildungen, wie schädelknochendefekte, omphalocele und gastroschisis, wurden beobachtet (orioli 2000 , gonzalez 1998 , hofmeyr 1998 , castilla 1994 , schüler 1992 . die zum abortversuch oral oder manchmal zusätzlich auch vaginal genommene dosis von misoprostol variierte zwischen 200 und 16.000 ? g und betrug durchschnittlich 800 ? g. die hohen dosen waren zeitlich über bis zu 20 tage verteilt angewendet worden. in einer retrospektiven brasilianischen fall-kontroll-studie ergab die medikamentenanamnese der mütter von 94 kindern mit möbius-sequenz, dass nahezu die hälfte misoprostol angewendet hatte. in einer kontrollgruppe von kindern mit neuralrohrdefekten waren es lediglich 3 % der mütter. zwei prospektive kohortenstudien zu misoprostol fanden keine auffälligkeiten bei schwangerschaftsverlauf und befinden der neugeborenen, allerdings betrug die anzahl exponierter mütter nur 125 bzw. 86 und schließt bei derart selten auftretenden defekten kein risiko aus (bellemin 2000 , schüler 1999 ). ein teil der mütter hatte misoprostol als schutz vor magengeschwüren bei einer behandlung mit nichtsteroidalen antirheumatika eingenommen. schon 200 ? g misoprostol können den arteriellen strömungswiderstand in den aa. uterinae dopplersonographisch nachweisbar heraufsetzen. dieser effekt kann die beobachteten disruptionsfehlbildungen als folge einer perfusionsstörung erklären (yip 2000) . zusammenfassend muss nach (versehentlicher) misoprostolanwendung ein geringes, teratogenes risiko angenommen werden. obwohl für keine der indikationen in der schwangerschaft zugelassen, ist ein trend zu beobachten, dass misoprostol vermehrt eingesetzt wird, sei es zur abortinduktion, zur geburtseinleitung oder in der postpartalperiode. sowohl die einfache applikation per os als auch der preis spielen dabei eine rolle. so ist misoprostol bei der geburtseinleitung nach blasensprung das wirkungsvollste medikament, das ohne zusätzliche applikationsbedingte infektgefährdung eingesetzt werden kann. es wird in der who-liste der essentiellen medikamente geführt (world health organization 2005) . eine mögliche überstimulation und pathologische ctg-muster geben allerdings anlass, vor einem unkritischen einsatz zu warnen. bei zustand nach sectio oder anderen transmuralen eingriffen ist misoprostol wegen deutlich erhöhter gefahr einer uterusruptur kontraindiziert. wirkorte sind vor allem der uterusmuskel und die milchdrüsenausführungsgänge. voraussetzung für die oxytocinwirkung am schwangeren uterus ist ein sehr komplexes geschehen. dazu gehören eine abnahme der estrogen-und progesteronkonzentration im blut mit einer verminderung der § -und g -adrenergen sicherung der uterusmuskulatur. die wehenanregende wirkung soll durch eine depolarisierung der muskelzellmembran ausgelöst werden. während der schwangerschaft erhöht sich die oxytocinkonzentration im blut nur gering. erst am ende steigen sowohl die konzentration als auch die zahl der oxytocinrezeptoren im myometrium deutlich an. während der verschiedenen geburtsphasen bis zum pressen kann ein anstieg der oxytocinkonzentration um das 3-bis 4fache beobachtet werden. diese konzentrationserhöhung wird beispielsweise während der austreibungsphase durch den so genannten ferguson-reflex bewirkt. dabei wird der druckreiz von dem in der kreuzbeinhöhle gelegenen frankenhäuserschen ganglion über rückenmarksbahnen zum hypophysenhinterlappen geleitet. (higby 1999 , katz 1999 . eine wirkliche prävention von frühgeburten muss weiter greifen. kein langzeittokolyse-schema hat eindeutig zur verringerung von kindlicher morbidität und mortalität beigetragen (higby 1999) . als wehenhemmer wurden bzw. werden g -adrenerge substanzen, calciumantagonisten, magnesium, prostaglandin-und oxytocinantagonisten und nitroglycerin verwendet. am weitesten verbreitet sind verschiedene g 2 -selektive sympathomimetika. diese auch in der asthmatherapie bewährten pharmaka haben weniger kardiovaskuläre nebenwirkungen als die nichtspezifischen g -sympathomimetika. g 2.14.5 g 2 -sympathomimetika pharmakologie und toxikologie. fenoterol (partusisten ® ) ist das in deutschland am meisten zur wehenhemmung verwendete g 2 -sympathomimetikum. auch clenbuterol, ritodrin, salbutamol, terbutalin und das nicht g 2 -spezifische hexoprenalin gehören zu den in der tokolyse gebräuchlichen g -sympathomimetika. bei intravenöser applikation begrenzen kardiovaskuläre wirkungen die anwendung von g -sympathomimetika. seit langem und kontrovers wird die wirksamkeit der oralen behandlung erörtert (baumgarten 1985) . obwohl vergleichbare konzentrationen wie bei der intravenösen behandlung erreicht werden (von mandach 1995), wird eine effektive tokolytische wirkung angezweifelt. tierexperimentell und in einzelnen fallberichten beim menschen wurden myokardnekrosen beim fetus und myokardinfarkte bei der mutter nach tokolyse mit g 2 -sympathomimetika beobachtet. ein erhöhter sauerstoffbedarf des myokards zusammen mit dem durch das tokolytikum bedingten intrazellulären calciumeinstrom wird als ursache diskutiert. ein vermuteter kardioprotektiver einfluss von verapamil führte zeitweise zur kombination beider pharmaka (weidinger 1973) , bis berichte über lungenödeme unter dieser kombination bei gleichzeitiger überwässerung erschienen (grospietsch 1981) . lungenödeme wurden auch bei einer tokolyse mit ritodrin alleine wiederholt beschrieben. insbesondere bei kombination mit corticosteroiden steigt die glucosekonzentration. das kann bei insulinabhängigen diabetikerinnen zum abrupten anstieg des insulinbedarfs führen. wiederholt wurden hyperkinetische verhaltensauffälligkeiten im kindesalter als folge wochenlanger g -sympathomimetischer tokolyse diskutiert. auch über passagere neurologische abweichungen in den ersten lebenstagen, die durch entsprechende tests im vergleich zu nicht exponierten neugeborenen ermittelt wurden, ist berichtet worden (thayer 1997) . eine abschließende beurteilung ist hierzu bisher nicht möglich. empfehlung für die praxis: eine kurzzeittokolyse mit g 2 -sympathomimetika, kontinuierlich intravenös oder als bolusgabe (spätling 1993 (higby 1999 , morales 1993 . higby und mitarbeiter (1993) sahen die prostaglandinantagonisten wie indometacin sogar als die einzig effektiven tokolytika an. sulindac hat entgegen anders lautender mitteilungen die gleichen nebenwirkungen wie andere prostaglandinantagonisten (kramer 1999) . diese mittel können zum vorzeitigen verschluss des ductus arteriosus botalli und über eine herabgesetzte nierenfunktion des fetus zum oligohydramnion führen. dies ist offenbar bei kurzzeitiger tokolyse (höchstens 48 stunden) und vor woche 30 kaum problematisch (norton 1993) . andererseits sind generelle vorteile dieser wirkstoffgruppe gegenüber den g 2 -sympathomimetika und calciumantagonisten nicht erwiesen. indometacin wurde auch zur behandlung des polyhydramnions angewendet (nordstrom 1992) . wenn die letzte indometacin-applikation nicht länger als 48 stunden zurücklag, war bei sonst vergleichbarem befinden des neugeborenen eine surfactant-therapie etwas häufiger erforderlich als bei nicht exponierten kindern (abbasi 2003) . beim vergleich von 56 frühgeborenen mit intrakranieller hämorrhagie fand sich gegenüber 224 kontrollen kein signifikanter zusammenhang mit einer indometacin-tokolyse (suarez 2001) . von 8 frühgeborenen, bei denen eine chirurgische intervention wegen persistierendem ductus arteriosus erforderlich wurde, war ein größerer anteil intrauterin mit indometacin exponiert als bei 69 konservativ therapierten kindern (suarez 2002) . als ursache hierfür wurde eine schädigung der intima des ductus diskutiert, die den spontanverschluss verhindert hat (siehe auch kapitel 2.1.11). in einer metaanalyse beschreiben cuzzolin und mitarbeiter (2001) fälle mit renalen komplikationen als ausdruck möglicher nephrotoxizität nach tokolytischer applikation von prostaglandinantagonisten, weisen aber darauf hin, dass diese eher selten sind. beim vergleich der verträglichkeit dieser mittel ergaben sich widersprüchliche ergebnisse. sawdy und mitarbeiter (2003) fanden bei indometacin, sulindac und nimesulid keinen unterschied in der wirksamkeit der tokolyse sowie bei maternalen oder neonatalen nebenwirkungen. sciscione und mitarbeiter (2000) wiesen jedoch auf ein unter indometacin erhöhtes risiko für bronchopulmonale dysplasien hin. empfehlung für die praxis: eine tokolyse mit prostaglandinantagonisten ist möglich. auswirkungen auf den kreislauf und die nierenfunktion des fetus mit resultierendem oligohydramnion müssen bedacht werden (siehe auch kapitel 2.1.11). g 2.14.9 oxytocinantagonisten pharmakologie und toxikologie. seit dem jahr 2000 ist der oxytocinantagonist atosiban für die wehenhemmung zugelassen. es ist ein parenteral wirksames spezifisches tokolytikum mit wenigen nebenwirkungen. aus preisgründen wird es in deutschland überwiegend bei problemsituationen eingesetzt, wie z. b. diabetes mellitus. fetotoxische wirkungen wurden bisher nicht beschrieben. empfehlung für die praxis: der klinische wert von atosiban zur wehenhemmung ist gesichert. g 2.14.10 andere tokolytika früher wurde ethylalkohol erfolgreich als tokolytikum eingesetzt. seine wirkung beruht auf der hemmung der oxytocinausschüttung. per intravenöser zufuhr wurden 2‰ und mehr im mütterlichen blut angestrebt. da die schädigende wirkung von alkohol auf die kindliche entwicklung nachgewiesen ist, gehört diese therapie nicht mehr zu den akzeptablen tokolytischen maßnahmen. nitroglyzerin als pflaster und i.v. verabreicht hat sich in kleineren untersuchungen als wirksames tokolytikum erwiesen. kopfschmerzen waren ein häufiges therapiebedingtes symptom, das seine weitere verbreitung verhinderte. negative auswirkungen auf den kreislauf des neugeborenen sind aufgrund der kurzen halbwertszeit nicht wahrscheinlich (black 1999 . der oral verfügbare vasopressin-v 1a -rezeptor-hemmstoff relcovaptan hat sich in einer kleinen randomisierten studie gegenüber plazebo als wirksam bei der wehenhemmung erwiesen (steinwall 2005) . empfehlung für die praxis: alkohol ist kontraindiziert. nitroglyzerin kann, wenn eine entsprechende indikation vorliegt, unter berücksichtigung der nebenwirkungen als tokolytikum eingesetzt werden. g 2.14.11 vaginaltherapeutika es gibt hinweise dafür, dass die behandlung bakterieller vaginosen frühgeburten verhindern kann (hoyme 2003 , donders 1999 . bei risikoschwangerschaften scheint eine protektive wirkung möglich durch eine systemische antibiotische behandlung, die eher als eine vaginale applikation von beispielsweise clindamycin (z. b. sobelin ® ) oder metronidazol (z. b. arilin ® ) eine aszendierende infektion vermeidet bzw. heilt (donders 2000 , joesoef 1999 . eine systemische (orale) antiinfektive therapie führt bei berücksichtigung der für die schwangerschaft empfohlenen mittel zu keinem entwicklungstoxischen risiko (siehe kapitel 2.6). problematisch sind povidon-iod als vaginal-suppositorien und iodspülungen der scheide wegen der möglichen passageren beeinträchtigung der fetalen schilddrüsenfunktion ab woche 12 (siehe abschnitt 2.17.3). die behandlung mit anderen vaginaltherapeutika, die desinfizienzien enthalten, z. b. dequaliniumchlorid (fluomycin ® ), hexetidin (vagi-hex ® ), policresulen (albothyl ® ) oder mit estrogenen steht bisher nicht im verdacht, teratogen zu wirken. im bemühen um eine rationale therapie sollte man jedoch veraltete und in ihrer wirksamkeit umstrittene mittel meiden. auch der einsatz von nitrofuranen wie furazolidon und nifuratel (inimur ® ) sowie vom antimykotikum chlorphenesin ist kritisch zu prüfen. g 2.14.12 spermizide kontrazeptiva frei verkäufliche vaginale kontrazeptiva, die als creme, gel, tabletten oder schaumovula angeboten werden (z. b. patentex ® ), enthalten nonoxinol 9 als spermizid wirksame substanz. diese form der kontrazeption galt jahrelang als völlig ungefährlich, bis 1981 in den usa in einer studie an 763 kindern von müttern, die trotz anwendung vaginaler kontrazeptiva schwanger wurden, über einen geringen anstieg der fehlbildungsrate berichtet wurde (jick 1981) . eine metaanalyse mehrerer, z. t. erheblich umfangreicherer untersuchungen konnte diesen verdacht entkräften (einarson 1990 ). in zahlreichen publikationen wurde erörtert, dass der gebrauch dieses spermizids über eine schädigung der vaginalschleimhaut und eine störung der physiologischen bakterienflora eine hiv-infektion bei entsprechendem kontakt begünstigen könne (rosenstein 1998 , stafford 1998 . empfehlung für die praxis: eine konzeption trotz anwendung eines nonoxinol-9-haltigen vaginalen kontrazeptivums stellt nach heutigem wissen kein risiko dar. g 2.14.13 intrauterinpessare die kupferkonzentration im eileitergewebe ist bei frauen mit kupferhaltigen iucds (intrauterine contraceptive devices) erhöht. im serum finden sich jedoch keine erhöhten coeruloplasmin-und kupferkonzentrationen (wollen 1994) . einige 100 schwangerschaften mit liegendem (und verbleibendem) iucd sind bisher beschrieben worden. abort-und frühgeburtsraten sind im vergleich zu frauen erhöht, die sich das iucd entfernen ließen. sichere hinweise auf ein spezifisches fehlbildungsrisiko haben sich nicht ergeben (übersicht in . dies ist auch für das als intrauterines system (ius) bezeichnete produkt mit levonorgestrel (mirena ® ) zu erwarten. empfehlung für die praxis: ein verbleibendes iucd rechtfertigt aus embryotoxikologischer sicht weder einen risikobegründeten abbruch einer schwangerschaft noch erfordert es invasive diagnostik (siehe kapitel 1.15). hormone hormone sind körpereigene stoffe, die physiologische prozesse steuern. ihre regulation erfolgt auf drei ebenen, der zwischenhirn-hypothalamus-ebene (vorwiegend releasing-funktion), der stimulatorebene in der hypophyse und der drüsenebene in den jeweiligen organen. die ausschüttung der hormone wird über regelkreise zwischen den drei ebenen gesteuert. wenn die mutter mit hormonen behandelt wird, sind auch beim fetus auswirkungen auf den verschiedenen ebenen möglich. die in diesem abschnitt besprochenen klassischen hormone sind von den gewebshormonen oder mediatoren zu unterscheiden, zu denen u. a. auch die prostaglandine (siehe abschnitt 2.14.1) und leukotriene gehören. trh steuert die schilddrüsenfunktion und regt die prolaktinsekretion an. mit seinem analogon protirelin konnte man den effekt pränatal verabreichter corticoide auf die lungenreifung des fetus verstärken, eine günstige wirkung auf das neonatale atemnotsyndrom ließ sich jedoch nach auswertung von über 1.000 fällen nicht nachweisen (ballard 1998 , collaborative 1998 , actobat 1995 . glucocorticoide allein waren genauso wirksam. es wurde kontrovers diskutiert, ob die in der exponierten gruppe beobachtete leichte entwicklungsverzögerung im alter von 1 jahr durch trh bedingt ist (crowther 1997 , mccormick 1997 . ghrh (growth hormone releasing hormone). synthetische analoga sind sermorelin und somatorelin (ghrh ferring ® ). ghrh und seine analoga wirken durchblutungsmindernd im uterusbereich und hemmen die proliferation des endometriums. daher werden sie präoperativ zur verkleinerung von myomen eingesetzt. bei versehentlicher anwendung während der schwangerschaft sind abort und intrauterine wachstumsretardierung denkbar. diese effekte wurden bisher aber ebenso wenig beobachtet wie eine hormonwirkung auf den fetus (übersicht bei . gnrh (gonadotropin releasing hormone) bzw. lhrh (luteinizing hormone releasing hormone). synthetische analoga sind buserelin (z. b. profact ® ), gonadorelin (z. b. kryptocur ® ), goserelin (zola-dex ® ), leuprorelin (z. b. enantone ® ), nafarelin (synarela ® ) und triptorelin (z. b. decapeptyl ® ) . cetrorelix (cetrotide ® ) und ganirelix (orgalutran ® ) sind antagonisten der gnrh. therapeutisch werden gnrh-analoga bei hypothalamischer ovarialinsuffizienz und in der onkologie eingesetzt und ebenso wie die gnrh-antagonisten zur vermeidung eines vorzeitigen anstiegs des luteinisierenden hormons (lh) und damit eines vorzeitigen eisprungs im rahmen einer assistierten reproduktion. bei über 340 im 1. trimenon versehentlich mit gnrh-analoga behandelten schwangeren fanden sich weder eine häufung angeborener anomalien oder fehlgeburten noch eine hemmende wirkung auf das intrauterine wachstum (übersicht in cahill 1998 . in einer nur 6 kinder umfassenden untersuchung wurden bei 4 kindern im alter von durchschnittlich 8 jahren entwicklungsauffälligkeiten diagnostiziert, wie z. b. aufmerksamkeitsdefizite, motorische und sprachstörungen sowie bei einem kind eine epilepsie. die autoren führen dies auf einen möglichen entwicklungstoxischen effekt der gnrh-analoga zurück (lahat 1999) . klinische erfahrungen mit der versehentlichen gabe von gnrh-antagonisten bei einer bereits bestehenden schwangerschaft sind unzureichend für eine risikobewertung, bisher liegen jedoch keine verdachtsmomente für eine schädigung des embryos vor. bei der üblichen anwendung in der reproduktionsmedizin scheinen gnrh-agonisten und -antagonisten hinsichtlich wirksamkeit und schwangerschaftsverlauf vergleichbar zu sein. somatostatin (somatostatin ® ) und octreotid (sandostatin ® ), ein synthetisches octapeptidderivat des somatostatins, hemmen sowohl die freisetzung des somatotropins (sth) wie auch des thyreoidea stimulierenden hormons (tsh). unter den hypothalamushormonen nimmt somatostatin daher eine sonderstellung ein. therapeutisch wird es als hämostyptikum, bei karzinoiden und zur senkung der wachstumshormonkonzentration bei akromegalie verwendet. in einigen fallberichten wird über die behandlung schwangerer mit octreotid berichtet, ohne dass nebenwirkungen beobachtet wurden (boulanger 2004 , blackhurst 2002 , takeuchi 1999 , colao 1997 . lanreotid (somatuline autogel ® ), ein analogon des somatostatins, wird seit 2005 zur therapie der akromegalie eingesetzt. pegvisomant (somavert ® ) ist ein somatotropin-rezeptorantagonist, der bei akromegalie eingesetzt wird und -verglichen mit den bisherigen therapieoptionen -den insulin-like-growth-factor-1 (igf-1) und damit die symptome der akromegalie am effektivsten senkt (stewart 2003) . erfahrungen zur anwendung in der schwangerschaft liegen noch nicht vor. empfehlung für die praxis: für den einsatz der hypothalamischen releasinghormone gibt es während der schwangerschaft kaum eine indikation. eine versehentliche applikation erfordert weder einen risikobegründeten schwangerschaftsabbruch noch invasive diagnostik (siehe kapitel 1.15). g 2.15.2 hypophysenvorderlappenhormone im hypophysenvorderlappen (hvl) werden hormone gebildet, die endokrine körperdrüsen stimulieren oder regulieren. die freisetzung der hvl-hormone wird durch hypothalamische releasinghormone gesteuert. hypophysäre hormone sind aufgrund ihrer hohen molekularmasse nicht plazentagängig, eine direkte beeinflussung des fetus ist daher nicht zu erwarten. die folgenden hormone gehören zu den hvl-hormonen. adrenocorticotropes hormon (acth), als medikament tetracosactid (synacthen ® ), stimuliert die synthese der gluco-und mineralocorticoide in der nebennierenrinde. thyreotropin oder thyreoidea stimulierendes hormon (tsh) stimuliert die synthese der schilddrüsenhormone. somatotropin (sth) oder wachstumshormon (gh) (z. b. genotropin ® , norditropin ® ), ein dem somatotropin strukturell und funktionell ähnliches hormon, wird von der plazenta mit fortschreiten der schwangerschaft in zunehmender menge gebildet. es wird auch als humanes plazentares laktogen (hpl) oder seltener als humanes choriales somatomammotropin (hcs) bezeichnet. funktionell hat es ähnlichkeit mit prolaktin (siehe unten). zu den gonadotropinen zählen das follikelstimulierende hormon (fsh) (urofollitropin, follitropin alpha, follitropin beta; z. b. gonalf ® 75, puregon ® ) und das luteinisierungshormon (lh). während der schwangerschaft wird das dem lh analog wirkende hcg (humanes choriongonadotropin) in der plazenta synthetisiert. prolaktin fördert zusammen mit einigen anderen hormonen das wachstum der milchgänge und die synthese der milchproteine, außerdem beeinflusst es den flüssigkeitshaushalt der mutter. es hat keine therapeutische bedeutung. von den hypophysenvorderlappenhormonen werden fsh und gemische aus fsh und lh therapeutisch eingesetzt, dazu gehören plazentares hcg (humanes choriongonadotropin; z. b. choragon ® ) und hmg (humanes menopausengonadotropin). analoga sind menotropin (menogon ® ) bzw. urogonadotropin. indikationen für diese hormonbehandlung sind ovulationsinduktion und erhaltung des corpus luteum. eine stimulierung der ovulation mit gonadotropinen kann zu mehrlingsschwangerschaften führen, darunter in 5-6 % zu drillingen (scialli 1986 ). zwei publikationen beschreiben eine komplexe fehlbildung und vier neuroblastomfälle im ersten lebensjahr nach gonadotropinstimulation (mandel 1994 , litwin 1991 . diese befunde wurden durch andere untersuchungen ebenso wenig bestätigt wie andere risiken für den verlauf der schwangerschaft oder die spätere kindesentwicklung. es gibt auch keine nennenswerten hinweise auf eine schädigung, wenn hormone des hypophysenvorderlappens versehentlich während einer schwangerschaft appliziert wurden. melatonin steuert periphere, dem biorhythmus unterworfene vorgänge im organismus. es stimuliert die progesteronsekretion, hemmt die prostaglandinsynthese und hat (experimentell) einen tokolytischen effekt. es liegen keine ausreichenden erfahrungen zur therapeutischen anwendung von melatonin in der schwangerschaft vor, z. b. zur vermeidung des jetlags bei interkontinentalflügen. empfehlung für die praxis: für die gabe von hypophysenvorderlappenhormonen gibt es in der schwangerschaft keine indikation. eine versehentliche applikation rechtfertigt weder einen risikobegründeten schwangerschaftsabbruch noch invasive diagnostik (siehe kapitel 1.15). eine untersuchung von 2.587 schwangerschaften, in denen bromocriptin während der ersten wochen gegeben wurde, zeigte zwar einen geringen anstieg der frühabortrate, jedoch keine hinweise auf teratogene effekte (krupp 1987) . da die meisten frauen die therapie nach feststellung der schwangerschaft abgesetzt hatten, bestätigt das ergebnis der untersuchung gleichzeitig die unschädlichkeit der weiter bestehenden hyperprolaktinämie für den sich entwickelnden fetus. eine studie mit 27 schwangerschaften bewies ebenfalls verträglichkeit und wirksamkeit einer therapie von mikro-und makroprolaktinomen mit bromocriptin oder lisurid, selbst wenn sie bis in die frühschwangerschaft hinein erfolgte. treten bei makroprolaktinomen im verlauf der schwangerschaft ophthalmologische probleme auf, wird die wiederaufnahme der therapie empfohlen (ventz 1996) . in einzelfällen empfiehlt sich eine dauertherapie während der gesamten schwangerschaft. cabergolin, das aufgrund seiner längeren wirkdauer nur ein-bis zweimal pro woche eingenommen werden muss, hat in über 300 unter dieser therapie entstandenen schwangerschaften keinen anhalt für teratogene effekte gezeigt (ricci 2002 , robert 1996 , selbst wenn in einzelnen fällen durchgehend behandelt wurde (de turris 2003 , jones 1997 . bei 9 schwangerschaften, in denen die frauen wegen einer bromocriptinresistenz mit quinagolid therapiert wurden, zeigten die neugeborenen keine auffälligkeiten. in 4 fällen war eine therapie bis zur geburt erforderlich (morange 1996) . weitere 159 vom hersteller gesammelte schwangerschaftsverläufe, bei denen durchschnittlich 37 tage in die schwangerschaft hinein behandelt wurde, geben ebenfalls keine hinweise auf entwicklungstoxische effekte (zitiert in webster 1996) . metergolin ist wahrscheinlich ähnlich wie die übrigen dopaminagonisten zu bewerten. die wenigen erfahrungen reichen für eine differenzierte risikobewertung nicht aus. empfehlung für die praxis: bromocriptin und cabergolin sind bei hyperprolaktinämischer amenorrhö aufgrund der umfangreichen erprobung dopaminagonisten der wahl. nach der konzeption sollte das mittel in der regel abgesetzt werden. eine weiterbehandlung rechtfertigt jedoch weder einen risikobegründeten schwangerschaftsabbruch noch invasive diagnostik (siehe kapitel 1.15). dies gilt auch für die anwendung von lisurid, metergolin und quinagolid. g 2.15.4 hypophysenhinterlappenhormone pharmakologie und toxikologie. von der neurohypophyse, dem hypophysenhinterlappen (hhl), werden oxytocin und vasopressin (adiuretin) sezerniert. strukturell ähneln diese oktapeptidhormone den hypothalamischen hormonen. oxytocin (z. b. syntocinon ® ) ist das klassische wehenhormon. während der schwangerschaft wird es in zunehmender menge gebildet und gleichzeitig durch die ebenfalls gesteigerte synthese des enzyms schwangerschaftsoxytocinase inaktiviert. erst bei fetaler reife wird dieses gleichgewicht zugunsten des oxytocins verändert oder vorzeitig bei einer plazentafunktionsstörung, so dass kontraktionen des uterus über § -rezeptoren induziert werden. eine hypoxie des fetus kann als folge einer oxytocinüberdosierung und überstimulation des uterus im rahmen der geburtseinleitung auftreten (siehe auch kapitel 2.14). vasopressin oder antidiuretisches hormon (adh) spielt therapeutisch auch in der schwangerschaft eine rolle bei der behandlung des diabetes insipidus. über teratogene wirkungen wurde bisher nicht berichtet (ray 1998) . das enzym schwangerschaftsoxytocinase inaktiviert neben oxytocin auch vasopressin. von den synthetischen analoga argipressin, desmopressin (z. b. minirin ® ), lypressin, ornipressin und terlipressin (z. b. glycylpressin ® ) wurde zur behandlung des schwangerschaftsbedingten diabetes insipidus am häufigsten desmopressin verschrieben. die tierexperimentell induzierbaren, offenbar durch vasokonstriktion hervorgerufenen peripheren extremitätenanomalien wurden beim menschen bisher ebenso wenig beobachtet wie andere spezifische schwangerschaftsstörungen. allerdings ist die zahl dokumentierter verläufe mit rund 50 für eine differenzierte risikobeurteilung zu klein (siristatidis 2004 , ray 1998 . in fällen mit thrombozytenfunktionsstörung, wie z. b. nach einer therapie mit acetylsalicylsäure (ass), vermag desmopressin die aktivität der thrombozyten zu stimulieren. der einsatz erfolgt meist kurzfristig peripartal. empfehlung für die praxis: oxytocin darf in der geburtshilfe zur einleitung und verstärkung von wehen eingesetzt werden. schwere fälle von adh-mangel (diabetes insipidus) rechtfertigen die gabe von vasopressin bzw. desmopressin in der schwangerschaft. dabei sind jedoch genaue kontrollen der kreislauf-und nierenfunktion unerlässlich. auch bei einer thrombozytenfunktionsstörung kann desmopressin gegeben werden. eine behandlung mit den anderen vasopressinanaloga rechtfertigt weder einen risikobegründeten schwangerschaftsabbruch noch invasive diagnostik (siehe kapitel 1.15). die hormonalen veränderungen und der geänderte stoffwechselbedarf während der schwangerschaft gehen bei jeder gesunden frau mit einer physiologischen anpassung der schilddrüsenfunktion einher. dies ist eine wichtige voraussetzung für die normale embryonale und fetale entwicklung sowie für eine ungestörte schwangerschaft. die fetale schilddrüse nimmt ihre aktivität am ende des dritten schwangerschaftsmonats auf (burrow 1994) , vorher ist der embryo ganz auf die thyroxinversorgung durch die mutter angewiesen. in der schwangerschaft steigt der mütterliche bedarf an iodid. sowohl die mütterliche als auch die fetale schilddrüsenfunktion sind von einer ausreichenden iodzufuhr abhängig. in iodmangelregionen muss daher möglichst schon vor der schwangerschaft eine ausreichende iodversorgung sichergestellt werden. eine substitution erst nach dem 2. trimenon kann bei gravierendem iodmangel-reifungsstö-rungen des zentralnervensystems nicht mehr verbessern (xue-yi 1994 , pharoah 1984 . der tägliche iodbedarf während der schwangerschaft beträgt 260 ? g. auch in der bundesrepublik deutschland ist die iodaufnahme häufig unzureichend. da eine zufuhr durch iodsalz, iodierte nahrungsmittel und seefische unzuverlässig erscheint, sollten während der schwangerschaft täglich 200 ? g mit tabletten substituiert werden. g 2.15.6 hypothyreose, triiodthyronin (t 3 ) und thyroxin (t 4 ) hypothyreote schwangere haben ein höheres risiko für komplikationen (glinoer 1997) und außerdem kann eine hypothyreose die geistige entwicklung des kindes beeinträchtigen. dies ist seit langem insbesondere im zusammenhang mit iodmangel bekannt. eine neuere studie an über 60 hypothyreoten frauen (nach 12 schwangerschaftswochen diagnostiziert) ergab, dass ihre bis zum alter von 2 jahren nachverfolgten kinder mental und motorisch schlechtere testergebnisse zeigten als kinder von euthyreoten oder leicht hyperthyreoten schwangeren (pop 2003) . auch haddow (1999) kam bei einer untersuchung an ca. 60 sieben-bis neunjährigen kindern zu ähnlichen ergebnissen; die mütter litten in der schwangerschaft an einer diskreten hypothyreose. daher sollten unterfunktionen der mütterlichen schilddrüse gerade auch im interesse des werdenden kindes diagnostiziert und behandelt werden. zum risiko einer hypothyreose des neugeborenen nach thyreostatischer therapie der mutter siehe auch abschnitt 2.15.7. pharmakologie und toxikologie. die hormonal wirksamen schilddrüsenhormone sind die l-formen von triiodthyronin (t 3 ) und thyroxin (t 4 ), die nur in freier, nicht-proteingebundener form stoffwechselaktiv sind. t 3 ist dabei das biologisch wirksame hormon, das relativ schnell anflutet und eine kürzere wirkdauer hat, während t 4 als ein weniger wirksames prohormon oder hormondepot anzusehen ist, das bedarfsgesteuert zu t 3 deiodiert wird. die plazenta benötigt für ihre entwicklung schilddrüsenhormone, sie deiodiert t 4 zu rt 3 (reverses t 3 ) und t 3 zu t 2 . die plazenta lässt schilddrüsenhormone nur eingeschränkt passieren (burrow 1994) . jedoch kommt bei fetaler schilddrüsenagenesie ein quantitativer transfer aufgrund des dann bestehenden hohen konzentrationsgradienten zustande. an arzneimitteln stehen levothyroxin (z. b. eferox ® ) und liothyronin (z. b. thybon ® ) oder kombinationspräparate (z. b. novothyral ® ) zur verfügung. teratogene oder fetotoxische wirkungen sind bei den üblichen dosierungen, die physiologische verhältnisse herstellen, nicht zu erwarten. in der schwangerschaft steigt der bedarf an schilddrüsenhormon, so dass hypothyreote frauen ihre dosis entsprechend anpas-sen müssen. als kontrollparameter für die richtige therapeutische einstellung dient der tsh-wert (alexander 2004) . empfehlung für die praxis: im bedarfsfall sollten präparate mit levothyroxin verordnet werden, da der mütterliche organismus durch die konversion zu triiodthyronin die kontrolle über die tatsächliche hormonaktivität behält. falls erforderlich, ist auch iod zu substituieren. zu beginn einer schwangerschaft (ab 5 schwangerschaftswochen) sollte die t 4 -dosis um ca. 30 % gesteigert werden. als faustregel gilt die empfehlung, dass schwangere nach feststellung der schwangerschaft die thyroxindosis um 25-50 ? g erhöhen sollen. im 2. trimenon ist eine weitere dosiserhöhung erforderlich und zwar auf 40-50 % über der ausgangsdosis vor der schwangerschaft. mit dem tsh-wert lässt sich die therapeutische einstellung kontrollieren. schilddrüsenhormone sollen nicht parallel zu einer thyreostatischen therapie gegeben werden, da dies den bedarf an plazentagängigen thyreostatika erhöht. g 2.15.7 hyperthyreose und thyreostatika eine unbehandelte, manifeste hyperthyreose der mutter stellt ein risiko für die schwangerschaft und den fetus dar. beschrieben sind fetale wachstumsretardierung, präeklampsie, frühgeburt und intrauteriner fruchttod bzw. totgeburt (glinoer 1997) . bei der basedow-krankheit wie auch bei der hashimoto-thyreoiditis, die in der regel zur hypothyreose führt, sollten zu beginn der schwangerschaft und am anfang des 3. trimenons die schilddrüsen-autoantikörper bei der schwangeren bestimmt werden. hohe werte, besonders von tsh-r-immunglobulinen (= tsi) sind ein hinweis darauf, dass diese antikörper diaplazentar übergehen könnten. man schätzt, dass es auf diese weise bei 1-2 % der schwangeren mit basedow-krankheit zu einer vorübergehenden hyperthyreose beim fetus bzw. neugeborenen kommt (carrol 2005) . eine kürzlich veröffentlichte prospektive studie an 115 frauen berichtet über eine wesentlich höhere rate von 12,6 %. vier neugeborene mit gesteigerter schilddrüsenfunktion hatten eine struma (rosenfeld 2005 . bei der schilddrüsenfunktion der neugeborenen wurden keine signifikanten unterschiede zwischen den verschiedenen thyreostatika gefunden. unter einer mütterlichen erhaltungsdosis von bis zu 100 mg ptu oder bis zu 10 mg methimazol pro tag zeigten 21 bzw. 14 % der kinder neonatal erhöhte tsh-werte (momotani 1997) . in der oben erwähnten studie von rosenfeld (2005) hatten 9,5 % der neugeborenen nach intrauteriner ptu-exposition eine hypothyreose und 5,4 % gleichzeitig eine struma. nicht bei allen dieser kinder war die schilddrüsenfunktion unmittelbar nach der geburt supprimiert, sondern zum teil erst bei der kontrolluntersuchung nach zwei wochen. fallbeschreibungen führten zu der hypothese, methimazol könne beim fetus hautdefekte (aplasia cutis), choanalatresie, ösophagusatresie, tracheo-ösophageale fisteln, hypoplastische brustwarzen, faziale dysmorphien und eine mentale sowie motorische entwicklungsverzögerung verursachen (barbero 2004 , karg 2004 , ferraris 2003 , karlsson 2002 , clementi 1999 , wilson 1998 , hall 1997 , johnsson 1997 , vogt 1995 . foulds (2005) kommt bei der sichtung aller kasuistiken zu dem schluss, dass es inzwischen 16 fallberichte von kindern oder feten gibt, die im 1. trimenon methimazol/carbimazol exponiert waren und die ein fehlbildungsmuster aufweisen, das als embryopathie zu werten ist. auf der anderen seite haben mehrere fallsammlungen weder nach behandlung mit ptu noch bei carbimazol/methimazol morphologische entwicklungsstörungen (wing 1994) oder auswirkungen auf größe und funktion der schilddrüse und auf die physische und intellektuelle entwicklung der kinder erkennen lassen (eisenstein 1992 , messer 1990 ). in einer multizentrischen prospektiven fall-kontroll-studie an 204 methimazol exponierten schwangerschaften fand sich kein erhöhtes gesamtfehlbildungsrisiko. allerdings wies unter den 8 kindern mit fehlbildungen eines eine choanalatresie und ein anderes eine ösophagusatresie auf (di gianantonio 2001) . aufgrund der jetzigen datenlage kann man feststellen, dass thyreostatika nicht zu einer nennenswerten zunahme der gesamtfehlbildungsrate führen. allerdings kann methimazol mit einer häufigkeit von 1/1.000 bis 1/10.000 exponierte feten zu o.g. organentwicklungsstörungen führen . eine sorgfältig eingestellte thyreostatische therapie führt heute kaum noch zu einer schweren angeborenen struma. früher wurden strumabedingte atemwegsobstruktion und behinderung des geburtsvorgangs als folgen der therapie mit thyreostatika, zum teil in kombination mit hoch dosiertem iod oder mit schilddrüsenhormonen, beschrieben (übersicht bei . insgesamt sollte sich die therapie mit thyreostatika eher an klinischen befunden, wie der herzfrequenz der mutter, als an laborwerten orientieren. natriumperchlorat (irenat ® ) ist nur selten bei übermäßiger iodaufnahme indiziert. in der schwangerschaft kann es den iodtransfer zum fetus beeinträchtigen. bei schwerer thyreotoxikose der mutter kann eine operative strumaresektion auch während der schwangerschaft indiziert sein. empfehlung für die praxis: eine manifeste hyperthyreose muss auch in der schwangerschaft behandelt werden. propylthiouracil ist, insbesondere im 1. trimenon, thyreostatikum der wahl, thiamazol (methimazol) und carbimazol sind als reservemittel zu betrachten. thyreostatika sind so niedrig wie möglich zu dosieren. die thyreostatische therapie soll nicht mit einer thyroxinsupplementierung kombiniert werden, da diese den thyreostatikabedarf der mutter erhöht. sowohl fetale hypothyreosen als auch eine hyperthyreose wurden gelegentlich nach mütterlicher thyreostatikatherapie infolge des plazentaren übergangs mütterlicher autoantikörper beschrieben. daher sollte die schilddrüse des fetus sonographisch kontrolliert werden. unverzichtbar ist das screening der schilddrüsenlaborparameter beim neugeborenen, das in vielen ländern routinemäßig durchgeführt wird. zu erwägen ist eine zweite kontrolle nach 14 tagen. leichte symptome einer hyperthyreose mit grenzwertigen laborparametern können in der schwangerschaft symptomatisch ohne thyreostatika behandelt werden, z. b. mit g -rezeptorenblockern wie propranolol oder metoprolol. nach therapie mit thiamazol (methimazol) und carbimazol im 1. trimenon sollte eine ultraschallfeindiagnostik zur bestätigung der normalen entwicklung des fetus angeboten werden. g 2.15.9 glucocorticoide pharmakologie. die nebennierenrinde (nnr) bildet 2 verschiedene hormongruppen, die gluco-und die mineralocorticoide, die u. a. den kohlenhydrat-und mineralstoffwechsel regeln. während der schwangerschaft treten veränderungen im hormonhaushalt der nnr auf. etwa vom 3. monat an erhöht sich die konzentration des cortisols im serum und die ausscheidung steigt zum ende der schwangerschaft an. therapeutisch sind vor allem glucocorticoide von bedeutung. man unterscheidet die nicht halogenierten von den halogenierten corticoiden. die ausschließlich lokal, dermal oder inhalativ verwendeten derivate werden an anderer stelle besprochen (siehe unter asthma, dermatika, augen-, nasen-und ohrentropfen). in der plazenta werden cortisol und prednisolon, nicht aber betamethason und dexamethason enzymatisch inaktiviert. perinatal finden sich im fetalen blut nur 10 % der mütterlichen konzentration von prednison und prednisolon; bei betamethason sind es 30 % und bei dexamethason nahezu 100 %. hauptindikationen für glucocorticoide. glucocorticoide sind in der therapie allergischer, entzündlicher und proliferativer erkrankungen wirk-sam. dabei werden unphysiologisch hohe dosierungen eingesetzt. außerdem werden sie in der substitutionstherapie bei nebennierenrindenversagen verabreicht und zur induktion der lungenreife des fetus. in tabelle 2.1 sind für die verschiedenen glucocorticoide die dosierungen zusammengefasst, deren wirksamkeit 10 mg prednisolon entsprechen. (pradat 2003 . eine meta-analyse aller bisher publizierten kohorten-und fall-kontroll-studien (carmichael 1999 , fraser 1995 ) ergibt ein signifikant erhöhtes risiko für spaltbildungen (odds ratio 3,4) bei nicht erhöhter gesamtfehlbildungsrate (parkwyllie 2000) . eine neue prospektive kontrollierte studie mit 311 im 1. trimenon exponierten müttern fand weder ein erhöhtes gesamtfehlbildungsrisiko, noch einen einzigen fall von lippen-gaumen-spalten (gur 2004) . auch hardy (2005) fand keine assoziation zwischen oraler steroidmedikation und spaltbildungen. zusammenfassend ist ein geringes risiko für gaumenspalten mit oder ohne lippenbeteiligung nicht auszuschließen, wenn während der sensiblen phase zwischen woche 8 bis 11 mit glucocorticoiden behandelt wird. eine sichere dosis lässt sich zwar nicht angeben, aber bei 10 bis 15 mg prednisolon/tag ist das individuelle risiko extrem gering. in abhängigkeit von der therapiedauer, dosis und indikation kann es bei behandlung mit glucocorticoiden zur intrauterinen wachstumsretardierung (iugr), zur frühgeburt sowie zu vorübergehender hypoglykämie, hypotonie und elektrolytstörungen beim neugeborenen kommen. in einer neueren arbeit konnten weder beim geburtsgewicht noch bei der basiskonzentration von cortisol und bei cortisolwerten nach stressinduktion durch impfungen unterschiede zwischen kindern mit längerer prednisolon-exposition in der schwangerschaft und solchen gesunder mütter gefunden werden. die kinder wurden mindestens bis zum alter von 4 monaten untersucht (miller 2004) . recht gut untersucht sind die effekte von pränatal verabreichten, plazentagängigen, halogenierten glucocorticoiden, um die lungenreifung zu fördern und ein respiratory-distress-syndrom (rds) beim neugeborenen zu verhindern. die überlebensrate der frühgeborenen steigt durch diese therapie, und hirnblutungen treten seltener auf. eine betamethason-oder dexamethason-therapie zur fetalen lungenreifung zwischen schwangerschaftswoche 24 und 33 führte in zwei untersuchungen an über 140 schwangeren in den tagen nach applikation bei den betamethason exponierten feten zu ausgeprägten, als stresssymptome interpretierten reaktionen, wie z. b. herabgesetzte atem-und körperbewegungen sowie eine eingeschränkte variabilität der herzfrequenz. das befinden der neugeborenen war letztlich unbeeinträchtigt (senat 1998 , mulder 1997 . in einer retrospektiven studie wurde ein vermehrtes auftreten von gastrointestinalem reflux bei neugeborenen gefunden, die vorgeburtlich mit steroiden behandelt wurden (chin 2003) . der wehenfördernde effekt sowie ein vorzeitiger verschluss des fetalen ductus arteriosus nach gabe von glucocorticoiden in der spätschwangerschaft scheinen klinisch nicht relevant zu sein. entgegen einzelner mitteilungen tritt eine neugeborenensepsis nach induktion der lungenreife mit glucocorticoiden nicht gehäuft auf. langzeitbeobachtungen bis zum alter von 12 bis 30 jahren zeigten überdies keine körperlichen, intellektuellen und psychosozialen auffälligkeiten nach glucocorticoidanwendung zur lungenreifung (dalziel 2005 , dessens 2000 , french 1999 , rotmensch 1999 . bei drohender frühgeburt nach schwangerschaftswoche 28 wird heute eine einmalige applikation von glucocorticoiden für ausreichend gehalten. wenn schwangere dexamethason bzw. betamethason zur lungenreifung des fetus vor woche 28 erhalten haben und später erneut eine frühgeburt droht, kann eine zweite gabe sinnvoll sein (rcog 2004 , nih 2001 . nach schwangerschaftswoche 34 ist eine medikamentöse unterstützung der lungenreifung in der regel nicht notwendig. empfehlung für die praxis: eine substitution mit corticoiden ist auch in der schwangerschaft selbstverständlich weiterzuführen. die induktion der lungenreifung bei drohender frühgeburt wird einmalig zwischen schwangerschaftswoche 28 und 34 durchgeführt. eine systemische behandlung der mutter mit glucocorticoiden darf bei entsprechender indikationsstellung auch in der schwangerschaft durchgeführt werden. prednison und prednisolon sind hierfür mittel der wahl. die erhaltungsdosis sollte zwischen woche 8 und 11 möglichst 10 mg/tag nicht überschreiten. notfallbehandlungen unterliegen selbstverständlich keinen dosisbeschränkungen. bei einer selten erforderlichen, höher dosierten behandlung über viele wochen sollte das fetale wachstum sonographisch beobachtet werden. dauert diese therapie bis zur geburt, muss eine nebenniereninsuffizienz des neugeborenen bedacht und ggf. behandelt werden. g 2.15.11 diabetes mellitus und schwangerschaft diabetes mellitus ist der sammelbegriff für heterogene störungen des stoffwechsels, deren leitsymptom die chronische hyperglykämie ist. man unterscheidet im wesentlichen drei typen. während typ i auf einer gestörten insulinsekretion beruht, sind typ ii und der gestationsdiabetes (gdm) durch eine gestörte insulinwirkung gekennzeichnet. beide ursachen können auch gleichzeitig vorkommen. ein vor oder zu beginn einer schwangerschaft bestehender mütterlicher diabetes mit ungenügender blutzuckerkontrolle (hba 1 c g 6,5 %) korreliert mit einer erhöhten rate an fehlbildungen. hba 1 markiert als "blutzuckergedächtnis" die blutzuckerstoffwechsellage der patientin für die dauer der erythrozytenüberlebenszeit (120 tage). je höher der hba 1 c ist, desto höher ist das risiko. bei einem hba 1 c von 8,5% wird ein fehlbildungsrisiko von 4 % angegeben; liegt das hba 1 c bei 10,5 %, steigt es auf 6 % an. zu den häufigsten fehlbildungen bei kindern diabetischer mütter zählen anomalien an wirbelsäule und extremitäten, am herz-kreislauf-system sowie neuralrohrdefekte, seltener sind urogenitale entwicklungsstörungen, gastrointestinale fisteln und atresien (übersicht bei ). bei diabetischen schwangeren ist die abortrate erhöht, die perinatale mortalität liegt deutlich über dem durchschnitt und die frühgeburtenrate beträgt fast 20 % (arbeitsgemeinschaft 2004, gamson 2004) . die neonatale morbidität ist gekennzeichnet durch makrosome neugeborene mit ungenügender organreife, mangelentwicklung und postpartalen stoffwechselstörungen, insbesondere von hypoglykämien. bei allen neugeborenen diabetischer mütter muss eine hypoglykämie ausgeschlossen werden. ein manifester diabetes mellitus kann in der schwangerschaft zu uteroplazentaren versorgungsproblemen und daraus resultierenden erkrankungen der mutter führen, wie z. b. präeklampsie. die überwiegende mehrheit der diabeteserkrankungen des typs ii und auch von erstmals in der schwangerschaft auftretendem gestationsdiabetes (gdm) entwickelt sich auf dem boden eines metabolischen syndroms ("wohlstands"-adipositas mit hyperlipidämie, hypertonie und glucosetoleranzstörung). am anfang besteht eine insulinresistenz der insulinabhängigen gewebe, so dass erhöhte insulinspiegel zur verwertung von glucose in den geweben notwendig sind. durch die hyperinsulinämie wird das hungergefühl erhöht, das wiederum zur erhöhten nahrungsaufnahme, weiterer adipositas etc. führt -ein circulus vitiosus. abnehmen führt zu sinkenden insulinspiegeln und zu einer erhöhten sensibilität und dichte der insulinrezeptoren. eine gewichtsreduktion auf einen body-mass-index (bmi) möglichst von p 27 kg/m 2 sollte vor einer schwangerschaft erreicht werden! zum risiko von vorbestehender adipositas für die schwangerschaft siehe auch abschnitt 2.5.26. eine gute stoffwechseleinstellung mit normoglykämie ist das ziel jeder diabetestherapie in der schwangerschaft, denn die diabetische fetopathie geht auf hyperglykämien der mutter zurück, die auch beim fetus zur hyperglykämie führt. dieser reagiert mit einer gesteigerten insulinproduktion, die zu einer beta-zell-hypertrophie/-hyperplasie führt. eine fetale hyperinsulinämie begünstigt auch die entwicklung eines respiratory-distress-syndroms (rds) durch ausbildung hyaliner membranen und beeinträchtigung der surfactantbildung in den fetalen pneumozyten durch eingriff in enzymatische vorgänge. bei kindern von müttern mit unzureichender blutzuckereinstellung in der schwangerschaft (meist beim unerkannten oder unzureichend behandelten gdm) ist das risiko erhöht, bereits in der pubertät oder im jungen erwachsenenalter adipös zu werden oder einen diabetes mellitus bzw. eine glukosetoleranzstörung zu entwickeln. übergewicht und gestationsdiabetes nehmen weltweit in den industrienationen zu, so dass inzwischen von einer häufigkeit des gdm von bis zu 20 % ausgegangen wird. die awmf-leitlinien empfehlen, bei jeder schwangeren (mindestens) einen glucosetoleranztest durchzuführen (arbeitsgemeinschaft 2001). während der schwangerschaft ändert sich die insulinempfindlichkeit: in woche 8-12 besteht eine erhöhte insulinempfindlichkeit mit höherer hypoglykämiegefahr, während in der zweiten schwangerschaftshälfte die insulinempfindlichkeit abnimmt, so dass oft eine dosissteigerung notwendig wird. sofort nach der entbindung kehrt die ursprüngliche insulinempfindlicheit zurück. empfehlung für die praxis: bei diabetes mellitus ist die exakte einhaltung der normoglykämie die beste voraussetzung für eine ungestörte prä-und postnatale entwicklung des kindes und eine geringe mütterliche morbidität. dieses ziel sollte möglichst schon vor einer geplanten schwangerschaft erreicht werden. jede schwangere diabetikerin sollte unabhängig vom typ des diabetes fachgerecht interdisziplinär betreut werden und möglichst in einem perinatalzentrum entbinden. g 2.15.12 insulin pharmakologie und toxikologie. das inselorgan, der endokrine anteil des pankreas, bildet und sezerniert insulin, glucagon und somatostatin. klinische bedeutung besitzt vor allem die störung der insulinproduktion, glucagon ist für die gegenregulation bei hypoglykämien wichtig. humaninsulin ist im gegensatz zu oralen antidiabetika nicht plazentagängig. eine bessere blutzuckerkontrolle und vorteile für das befinden des neugeborenen können erreicht werden, wenn in form einer intensivierten insulintherapie täglich mindestens dreimal präprandial insulin 381 ein kurzwirksames insulin appliziert wird, eventuell ergänzt durch ein langzeitinsulin zur nacht, anstelle der zweimaligen applikation eines langzeitinsulins. die substitutionstherapie mit humanem insulin bei schwangeren diabetikerinnen hat nach den sehr umfangreichen erfahrungen keine embryotoxischen wirkungen. das ideale insulin für die behandlung schwangerer sollte ähnlich wie die natürliche insulinsekretion des pankreas zu einer guten glykämischen kontrolle bei der mutter führen und nicht die plazenta passieren. außerdem sollte es keine oder kaum antikörperbildung auslösen ("not immunogenic"), denn es gibt hinweise darauf, dass anti-insulin-antikörper im gegensatz zu insulin die plazenta passieren können. die mütterliche morbiditätsrate soll durch ein neues insulin nicht erhöht werden und eine bestehende diabetische retinopathie sollte sich nicht verschlimmern (minimale igf-i-aktivität). in aller regel erfolgt die einstellung schwangerer mit humanem normalinsulin und verzögerungsinsulin. seit einigen jahren gibt es insulinanaloga: kurzwirksames insulinlispro (humalog ® ), insulinaspart (novorapid ® , novomix ® ), insulinglusilin (z. b. apidra ® ) und die langwirksamen präparate insulinglargin (lantus ® ) und insulindetemir (levemir ® ). insulinlispro ist in vielen, meist kleineren retrospektiven und prospektiven studien an insgesamt mehr als 500 schwangeren nach den oben genannten kriterien am besten untersucht (wyatt 2005 , cypryk 2004 , garg 2003 , masson 2003 , scherbaum 2002 , persson 2002 , bhattacharyya 2001 . bisher wurde unter insulinlispro keine erhöhte fehlbildungsrate beobachtet, das blutzuckertagesprofil gleicht dem von humaninsulin, der blutglucosewert 1 stunde postprandial ist bei insulinlispro niedriger (mecacci 2003) . daraus ist jedoch nicht generell abzuleiten, dass die neugeborenenparameter besser ausfallen. in einer niederländischen studie an 289 schwangeren mit typ-i-diabetes wurde festgestellt, dass im vergleich zu normalgewichtigen kindern insulinlispro in der gruppe makrosomer neugeborener mit 15% vs. 8 % überrepräsentiert war (evers 2002) . ein fortschreiten der diabetischen retinopathie unter insulinlispro wurde bisher nicht beobachtet, ist aber auch noch nicht ausreichend untersucht (loukovaara 2003 , buchbinder 2000 . nach dem stand der heutigen erfahrungen ist die bildung von insulinantikörpern bei behandlung mit insulinlispro und humaninsulin ähnlich niedrig (gamson 2004) . insulinaspart ist bisher weniger untersucht. eine multinationale europäische studie vergleicht zz. die mütterlichen und fetalen komplikationen bei typ-i-diabetikerinnen bei einer therapie mit insulinaspart und mit humaninsulin (actrapid ® ). insulinglusilin und die langwirksamen insulinanaloga wie insulindetemir sind fast gar nicht untersucht. aufgrund der hinweise, dass sich eine retinopathie unter insulinglargin verschlechtern könnte, sollten die langwirksamen insu-linanaloga spätestens bei feststellung der schwangerschaft abgesetzt bzw. umgestellt werden (übersicht gamson 2004) . einzelne fälle (devlin 2002) berichten über schwere nächtliche hypoglykämien unter normalinsulin, die nach umstellung auf insulinglargin nicht mehr auftraten. in der erprobung befindet sich das kurzwirksame inhalierbare insulin pramlintid. empfehlung für die praxis: ein typ-i-diabetes-mellitus muss schon vor einer schwangerschaft mit insulin gut eingestellt sein. humaninsuline sind mittel der ersten wahl. eine gut auf insulinlispro eingestellte frau muss in der gravidität nicht zwangsläufig umgestellt werden. langzeitanaloga sollten jedoch abgesetzt werden. schwangere mit einem typ-ii-diabetes oder einem gestationsdiabetes, der diätetisch allein nicht ausreichend therapiert ist, sollten humaninsulin erhalten. auch bei grenzwertig erhöhten blutglukosewerten und dem vorliegen einer fetalen makrosomie sollte mit einer insulintherapie begonnen werden. insulin tierischer herkunft sollte während der schwangerschaft wegen möglicher antikörperbildung nicht verwendet werden. bei schwangeren diabetikerinnen, die bereits insulinpflichtig waren, kann der insulinbedarf stark ansteigen. zur therapiekontrolle ist die ultraschallbiometrie des wachsenden fetus heranzuziehen. da glucocorticoide und tokolytika die kohlenhydrattoleranz der mutter verringern, sind bei gabe dieser medikamente besonders sorgfältige stoffwechselkontrollen anzuraten. g 2.15.13 orale antidiabetika pharmakologie und toxikologie. orale antidiabetika sind keine hormone und wirken nicht substitutiv wie insulin. die überwiegend verwendeten sulfonylharnstoffderivate stimulieren die noch funktionsfähigen g -zellen des pankreas. zu ihnen gehören als mittel der zweiten generation glibenclamid (= glyburid; z. b. euglucon ® n), glibornurid (glutril ® ), gliclazid (diamicron uno ® ), glimepirid (z. b. amaryl ® ), glipizid und gliquidon (glurenorm ® ). zu den sulfonylharnstoffen der ersten generation zählen acetohexamid, chlorpropamid, tolazamid und tolbutamid (orabet ® ). die biguanidderivate metformin (z. b. glucophage ® ) und phenformin vermindern die glucosesynthese in der leber, führen zu einer verzögerten glucoseresorption aus dem darm und zur verstärkten glucoseaufnahme in die muskulatur. acarbose (glucobay ® ) und miglitol (diastabol ® ) verringern als § -glucosidase-hemmstoffe die kohlenhydratresorption im darm. dies ist ein umstrittener weg der diabetestherapie. die glinide nateglinid (starlix ® ) und repaglinid (novonorm ® ) sind postprandiale glucoseregulatoren, die zu einer kurzfristigen insulinsekretion aus den g -zellen führen. sowohl bei diesen medikamenten wie auch bei den glitazonen pioglitazon (actos ® ) und rosiglitazon (z. b. avandia ® ), die als so genannte "insulin-sensitizer" die empfindlichkeit der peripheren zellen für insulin verbessern, fehlen wirksamkeitsbelege bezüglich der diabetesspezifischen spätfolgen. evidenzbasierte, endpunktbezogene, positive ergebnisse liegen nur für insulin, metformin und für sulfonylharnstoffpräparate vor. muraglitazar (pargluva ® ) ist wie die anderen glitazone auch ein aktivator von peroxisomen-proliferator-aktivierten-rezeptoren (ppar). die studienergebnisse zeigten ein erhöhtes risiko kardiovaskulärer ereignisse und todesfälle, so dass es von der us-amerikanischen federal drug administration (fda) bislang nicht zugelassen wurde. sitagliptin ist ein inkretin-mimetikum: im darm vorkommende hormone (inkretine) steigern bei nahrungsaufnahme bedarfsgerecht die insulinsekretion. bei diabetes werden weniger inkretine als bei gesunden produziert. sitagliptin blockiert den normalerweise raschen enzymabbau der inkretine. es ist noch nicht zugelassen. da orale antidiabetika den blutzucker nicht so zuverlässig regulieren wie insulin, sind sie wenig geeignet für die behandlung des diabetes in der schwangerschaft. studien zur anwendung in der gravidität gibt es zu glibenclamid und zu metformin. beim neugeborenen begünstigt es hypoglykämien, wenn bis zum ende der schwangerschaft behandelt wird. einige ältere untersuchungen beobachteten erhöhte fehlbildungsraten (piacquadio 1991) , die zunächst als hinweise für ein teratogenes risiko der oralen antidiabetika interpretiert wurden (towner 1995) . heute wird vermutet, dass die unter oralen antidiabetika auftretenden hyperglykämien selbst ein teratogenes potenzial besitzen. insofern sind auch substanzspezifische unterschiede in der plazentagängigkeit von untergeordneter relevanz, z. b. ist tolbutamid besser plazentagängig als glipizid (elliott 1994) und glibenclamid geht nur minimal über (koren 2001) . neuere fallberichte beobachteten kein erhöhtes fehlbildungsrisiko, eine differenzierte risikobeurteilung des teratogenen potenzials erlauben sie jedoch nicht. randomisierte untersuchungen fanden keine unterschiede im schwangerschaftsverlauf und beim status der neugeborenen bei mehreren 100 mit glibenclamid behandelten frauen mit gestationsdiabetes im vergleich zu insulin. die therapie wurde jeweils nach der embryogenese begonnen. im nabelschnurblut konnte glibenclamid nicht nachgewiesen werden, die insulinkonzentration war dort in beiden gruppen gleich. auch die anzahl hypoglykämischer kinder und das durchschnittliche geburtsgewicht unterschieden sich nicht signifi-kant (jacobson 2005 , langer 2005 , kremer 2004 ). jacobson (2005) beobachtete bei glibenclamid signifikant häufiger eine präeklampsie. ob diese befunde ausreichen, die bisherigen empfehlungen für die insulintherapie bei gestationsdiabetes infrage zu stellen, erscheint fraglich (greene 2000) . metformin stimuliert im gegensatz zu glibenclamid nicht die insulinsekretion und führt auch nicht zur hypoglykämie bei der schwangeren. bei übergewichtigen diabetikern ist die gabe eines wirkstoffs, der zu einer erhöhten insulinempfindlichkeit und zu einem verminderten insulinbedarf führt, sinnvoller als die gabe von glibenclamid. metformin wird nicht nur bei typ-ii-diabetikerinnen eingesetzt, sondern auch bei frauen mit einem pcos (polyzystisches ovar-syndrom) im rahmen der sterilitätsbehandlung, zur senkung der erhöhten abortrate und zur vermeidung bzw. therapie eines gestationsdiabetes. studien zur verträglichkeit im 1. trimenon sind rar. glueck (2004) fand bei 126 schwangerschaften keine hinweise auf ein teratogenes risiko. in mehreren studien konnte eine senkung der abortrate bei frauen mit einem pcos nachgewiesen werden (palomba 2005 , jakubowicz 2002 ). kontrovers diskutiert wird, wie lange metformin zur "stabilisierung der schwangerschaft" bei pcos gegeben werden sollte. bisher gibt es keine eindeutigen belege dafür, dass eine gabe über schwangerschaftswoche 6 bis 8 hinaus zu besseren ergebnissen führt. die von glueck ( & 2004 postulierte präventive wirkung hinsichtlich gestationsdiabetes durch eine über das 1. trimenon hinaus fortgesetzte therapie konnte in einer randomisierten prospektiven untersuchung nicht bestätigt werden (vanky 2004) . hier sind weitere studien notwendig. zu rosiglitazon und acarbose gibt es nur wenige einzelfallbeschreibungen (kalyoncu 2005 ), zu den übrigen antidiabetika liegen keine erfahrungen in der schwangerschaft vor. empfehlung für die praxis: auch eine typ-ii-diabetikerin sollte schon bei planung einer schwangerschaft mit insulin eingestellt werden. eine dennoch weitergeführte therapie mit oralen antidiabetika rechtfertigt keinen risikobegründeten schwangerschaftsabbruch (siehe kapitel 1.15). mit ultraschallfeindiagnostik sollte die morphologische entwicklung des fetus kontrolliert werden. es ist bisher nicht erwiesen, ob beim gestationsdiabetes nach dem 1. trimenon glibenclamid oder metformin eine alternative zum insulin darstellen. insulin ist nach wie vor die therapie der wahl. wurde metformin bei pcos zur unterstützung der schwangerschaft gegeben, sollte es um woche 6 bis 8 abgesetzt werden. g 2.15.14 estrogene pharmakologie und toxikologie. nur während der schwangerschaft wird außer estron und estradiol auch estriol synthetisiert, das sonst nur als metabolit auftritt. physiologisch und auch pharmakologisch wirken estrogene stimulierend auf das wachstum von uterus, eileitern sowie besonders auf das wachstum des endometriums. weiterhin bewirken sie eine proliferation des vaginalepithels, eine zunahme der zervixsekretion und eine weitstellung des zervikalkanals. die früher manchmal übliche gabe zur verbesserung der wehenbereitschaft am termin wurde durch wirksamere pharmaka abgelöst. therapeutisch werden estrogene heute zur hormonellen kontrazeption, zur substitution im klimakterium und zur malignombehandlung verwendet. zu den verfügbaren substanzen gehören estradiol (z. b. estrifam ® ) und seine derivate ethinylestradiol (bestandteil der meisten estrogenhaltigen "pillen"), estriol (z. b. estriol jena-pharm ® ) und mestranol (in esticia ® ). polyestradiol sowie die estrogene fosfestrol, chlorotrianisen und epimestrol sind derzeit nicht zugelassen. die relativ niedrig dosierten zubereitungen zur hormonalen kontrazeption (kombinationspräparate aus estrogen und gestagen) einschließlich der notfallkontrazeption ("pille danach") und zubereitungen zur behandlung einer amenorrhö sind aufgrund ihrer häufigen (versehentlichen) anwendung in der frühschwangerschaft recht gut untersucht. sie bergen offenbar kein nennenswertes risiko (ahn 2005, raman-wilms 1995, källén 1991), auch nicht für geschlechtsdifferenzierungsstörungen, wenn während des sensiblen zeitraumes nach schwangerschaftswoche 8 behandelt wurde. allerdings gibt es nach fallberichten aus den 70er jahren über herzfehlbildungen, vacterl-syndrom u. a. im zusammenhang mit der einnahme oraler kontrazeptiva in der schwangerschaft vereinzelt auch neuere publikationen, die eine erhöhte rate von (harnwegs-)anomalien diskutieren (li 1995) . auswirkungen einer intrauterinen exposition mit estrogenen auf die spätere fertilität konnten bisher nicht bestätigt werden. in einer übersichtsarbeit wurden alle bisherigen studien zu störungen der männlichen reproduktion infolge einer intrauterinen estrogeneinwirkung analysiert. hier wurden sowohl medikamente der mutter, physiologisch erhöhter estrogenspiegel (z. b. bei zwillingsschwangerschaften), vegetarische (soja-)diät (soja enthält nichtsteroidale phytoestrogene; siehe auch west 2005) und umweltschadstoffe mit estrogenartiger wirkung (organochlorverbindungen wie pcb oder dioxine; siehe auch kapitel 2.23) berücksichtigt. allenfalls beim hodenkrebs, nicht jedoch bei hypospadien, hodenhochstand oder spermienzahlen ließ sich eine gewisse assoziation erkennen . eine ältere publikation berichtet von abweichender psychosexueller entwicklung pränatal exponierter jungen, deren diabetische mütter mit estradiol und progesteron behandelt worden waren (yalom 1973 seit etwa 40 jahren werden progesteron (z. b. utrogest ® ) sowie halboder vollsynthetische derivate (z. b. 17-hydroxyprogesteron) zur behandlung des drohenden abortes eingesetzt. bis heute gibt es jedoch keinen wirkungsnachweis, deshalb ist das behandlungskonzept überholt (acog 2003) . bessere erfolgsquoten nach progesteronbehandlung können vorgetäuscht sein, da die patientinnen oft auch intensivärztlich und pflegerisch betreut werden. ein symposium der who über arzneimittelbehandlung während der schwangerschaft hat die nutzlosigkeit dieser therapie festgestellt, die in der bundesrepublik deutschland, in frankreich und italien verbreitet war, in skandinavien hingegen nicht praktiziert wurde (who-report 1984) . dennoch wird immer wieder beim drohenden abort die therapie mit gestagenen vorgeschlagen, heute meistens mit dem natürlichen progesteron. eine aktuell noch diskutierte indikation zur hormonellen verhinderung eines aborts ist die hcg-therapie bei der seltenen corpus-luteum-insuffizienz. der zusammenhang zwischen hormontherapie und vermehrtem auftreten von hypospadien wird kontrovers diskutiert (carmichael 2004 , källén 1992 . wenn überhaupt führen gestagene nur äußerst selten zu dieser häufig auch spontan vorkommenden und meist geringfügigen anomalie. die relativ niedrig dosierten zubereitungen zur hormonalen kontrazeption einschließlich der notfallkontrazeption ("pille danach") und produkte zur behandlung einer amenorrhö sind aufgrund ihrer häufigen (versehentlichen) anwendung in der schwangerschaft recht gut untersucht. sie bergen insbesondere hinsichtlich extragenitaler fehlbildungen nach heutigem wissen kein erkennbares risiko (ahn 2005, brent 2000 , raman-wilms 1995 , källén 1991 . allerdings gibt es nach fallberichten aus den 70er jahren über herzfehlbildungen, vacterl-syndrom u. a. im zusammenhang mit der einnahme von oralen kontrazeptiva in der schwangerschaft vereinzelt auch neuere publikationen, die eine erhöhte rate von (harnwegs-)-anomalien diskutieren (li 1995) . die notfallkontrazeption wird heute als reine gestagentherapie mit 2 × 0,75 mg bzw. 1 × 1,5 mg levonorgestrel (duofem ® , levogynon ® ) durchgeführt. sicherheit, verträglichkeit und nebenwirkungen haben ein so günstiges profil, dass in einigen ländern, wie z. b. der schweiz, eine verschreibungsfreie abgabe erfolgt. bei dieser therapie wird der eisprung verhindert und kein abort induziert. embryotoxische wirkungen wurden, falls die schwangerschaft doch weiter besteht, bisher nicht beschrieben (american academy of pediatrics 2005, food and drug administration 2003). geschlechtsdifferenzierungsstörungen durch gestagene in kontrazeptiver dosis während des sensiblen zeitraumes ab schwangerschaftswoche 8 wurden nicht beobachtet. wenn jedoch wiederholt deutlich höhere dosen der 19-nor-gestagene mit ihrem androgenisierenden potenzial eingenommen wurden, kann eine vorübergehende klitorisvergrößerung auftreten (übersicht bei . negative auswirkungen dieser intrauterinen exposition auf die fertilität im erwachsenenalter wurden bisher nicht vermehrt beobachtet. die entwicklung bis ins jugendalter scheint nach großen langzeituntersuchungen, z. b. zu depotpräparaten mit medroxyprogesteron ("dreimonatsspritze"), altersgemäß zu verlaufen (pardthaisong 1992) . früher wurde nach gabe androgener gestagene (norethisteronabkömmlinge), in höherer dosis als zur kontrazeption heute üblich, eine auswirkung auf das spätere geschlechtsspezifische verhalten der kinder angenommen. zur hoch dosierten anwendung von gestagenen, wie z. b. in der malignomtherapie, liegen keine ausreichenden erfahrungen vor. empfehlung für die praxis: während einer schwangerschaft gibt es keine stichhaltige indikation für die therapie mit gestagenen. dies gilt auch für das überholte behandlungskonzept mit progesteron bei drohendem abort. doch weder eine solche therapie noch in der frühschwangerschaft versehentlich eingenommene kontrazeptiva erfordern einen risikobegründeten schwangerschaftsabbruch oder zusätzliche diagnostik (siehe kapitel 1.15). das gilt für die heute üblichen niedrig dosierten ein-oder mehrphasenpräparate, die notfallkontrazeption mit levonorgestrel und die behandlung einer amenorrhö mit norethisteronacetat und ethinylestradiol. die (versehentliche) applikation hoch dosierter präparate für andere indikationen rechtfertigt ebenfalls keinen risikobegründeten abbruch der schwangerschaft. in einem solchen fall kann mit ultraschallfeindiagnostik die normale organentwicklung dokumentiert werden. g 2.15.16 diethylstilbestrol pharmakologie und toxikologie. diethylstilbestrol (des) ist ein synthetisches nichtsteroidales estrogenaktives arzneimittel, das in den 70er jahren in den usa zur therapie des drohenden abortes und außerdem zur begrenzung des längenwachstums bei heranwachsenden mädchen (venn 2004 ) verordnet wurde. großes internationales aufsehen erregte die entdeckung, dass bei töchtern, deren mütter während der schwangerschaft des erhalten hatten, im adoleszentenalter vermehrt adenokarzinome der vagina auftraten (herbst 1975) . dies ist der einzige beim menschen nachgewiesene fall für vorgeburtlich ausgelöste karzinome ("transplazentare karzinogenese"). das risiko für diese bei jungen frauen sonst seltene erkrankung wird mit bis zu 0,14 % angegeben. andere krebsrisiken, wie z. b. für brustkrebs, ließen sich nicht eindeutig nachweisen (hatch 1998) . mindestens 25 % der im 1. trimenon pränatal exponierten jungen frauen wiesen außerdem anomalien an scheide, uterus oder eileitern auf (mittendorf 1995) . andere untersucher konnten kein erhöhtes risiko für leiomyome und ovarialzysten erkennen, sahen aber häufiger parovarialzysten . bei männlichen nachkommen besteht offenbar ein erhöhtes risiko für kryptorchismus, testikuläre hypoplasie und abnorme samenzellmorphologie (mittendorf 1995) . ein erhöhtes hypospadierisiko bei söhnen, deren mütter als embryo selbst pränatal exponiert waren, wird kontrovers diskutiert , klip 2002 ). des weiteren gibt es hinweise darauf, dass solche frauen ein erhöhtes risiko für frühgeburten und andere schwangerschaftskomplikationen haben (papiernik 2005 zu den anabolika gehören z. b. clostebol, metenolon (z. b. in anti-focal ® ), nandrolon (z. b. deca-durabolin ® ) und tibolon (liviella ® ). für diese medikamente gibt es in der schwangerschaft ebenfalls keine behandlungsindikation. im zusammenhang mit kraftsport und bodybuilding werden jedoch "schwarz" importierte präparate verwendet, die auch ohne entsprechende deklaration androgene bzw. anabolika enthalten können. sie wurden schon "versehentlich" während einer schwangerschaft weiter genommen. die praktischen erfahrungen zur pränatalen verträglichkeit von androgen-und anabolika-präparaten reichen für eine differenzierte risikobewertung, auch bezüglich einer androgenisierenden wirkung, nicht aus. empfehlung für die praxis: androgene und anabolika sind während der schwangerschaft absolut kontraindiziert. eine versehentliche anwendung erzwingt jedoch keinen risikobegründeten schwangerschaftsabbruch (siehe kapitel 1.15). insbesondere bei wiederholter anwendung sollte mit ultraschallfeindiagnostik die organentwicklung kontrolliert werden. cyproteronacetat ist das im reproduktionsfähigen alter am häufigsten verschriebene antiandrogen. in kombination mit ethinylestradiol wird es als kontrazeptive pille (diane ® 35) angeboten. dieses präparat wird besonders bei gleichzeitig bestehender akne verschrieben. das bundesinstitut für arzneimittel und medizinprodukte (bfarm) hatte 1995 wegen des verdachts auf lebertumoren die anwendung von diane ® 35 drastisch eingeschränkt. das präparat sollte nur noch bei androgenisierungserscheinungen und akne mit narbenbildung verschrieben werden. die antiandrogene wirkung von cyproteronacetat kann theoretisch zur feminisierung männlicher feten führen. doch selbst bei versehentlicher fortführung der behandlung mit täglich 2 mg (in diane ® 35) bis in die sensible phase über schwangerschaftswoche 8 hinaus, ist eine feminisierung nicht beobachtet worden. vom hersteller wurden 23 schwangere mit männlichen feten registriert, die während der (nahezu) gesamten genitalentwicklungsphase 2 mg täglich eingenommen hatten und weitere 6 schwangere, die sogar 25-100 mg cyproteron täglich eingenommen hatten. die 28 lebend geborenen knaben waren normal entwickelt. bei einem spätabort wurden ebenfalls keine entwicklungsstörungen festgestellt. weitere fallserien deuten ebenfalls nicht auf teratogene effekte beim menschen hin (eigene daten und die des european network of teratology information services, entis). allerdings reicht der umfang an erfahrungen für eine differenzierte risikobewertung nicht aus. danazol, ein synthetisches modifiziertes androgen, leitet sich von ethisteron ab und ist ein antiestrogener hemmstoff. danazol wurde zur behandlung der endometriose, bei benigner knotenbildung in der brust, hereditärem angioneurotischem ödem und auch als kontrazeptivum eingesetzt. zahlreiche publikationen mit über 100 exponierten schwangeren offenbaren ein erhebliches virilisierendes risiko für weibliche feten, wenn täglich mit 200 mg noch nach schwangerschaftswoche 8 (funktionsaufnahme der androgenrezeptoren) behandelt wurde. bei normalem innerem genitale zeigten bis über 50 % der pränatal exponierten mädchen eine klitorisvergrößerung oder das vollbild eines weiblichen pseudohermaphroditismus. bei der späteren entwicklung fanden sich keine weiteren auffälligkeiten, wie z. b. virilisierung oder störungen des sexualverhaltens (übersicht bei . eine erhöhte abortneigung nach gabe von danazol könnte auch durch die endometriose als grunderkrankung verursacht sein. die wirkung der übrigen in diesem abschnitt angesprochenen antiestrogene und antiandrogene ist in der schwangerschaft nicht untersucht, so dass eine differenzierte risikobewertung nicht möglich ist. empfehlung für die praxis: antiestrogene, antiandrogene und danazol sind in der schwangerschaft absolut kontraindiziert. eine versehentliche applikation rechtfertigt jedoch keinen risikobegründeten schwangerschaftsabbruch (siehe kapitel 1.15). durch ultraschallfeindiagnostik sollte die ungestörte organentwicklung zumindest bei höher dosierten produkten bestätigt werden. g 2.15.19 mifepriston (ru486) pharmakologie und toxikologie. mifepriston ist ein progesteron-und glucocorticoid-antagonist. es wurde 1999 als abortivum in deutschland zugelassen. eine dosis von 600 mg ist für den abbruch einer frühschwangerschaft erforderlich, in kombination mit einem prostaglandinpräparat sind 200 mg jedoch ebenso effektiv (peyron 1993) . zu den pharmakologischen effekten des mifepristons zählen unter anderem die senkung der lh-(luteinisierungshormon-)sekretion, eine beschleunigte gelbkörperregression und die zunahme der kontraktilität der uterusmuskulatur. auswirkungen auf die plazentare produktion von progesteron, choriongonadotropin und humanem plazentaren laktogen wurden ebenfalls beobachtet. mifepriston wurde wegen seines progesteronantagonismus auch als monatlich einzunehmendes "interzeptivum" (wirksamkeit im gegensatz zum kontrazeptivum erst nach einer konzeption) versucht. es hat sich dabei allerdings als ebenso wenig zuverlässig erwiesen wie zur medikamentösen beendigung extrauteriner schwangerschaften. außerdem wird der einsatz zur zervixreifung, geburtseinleitung sowie bei endometriose und uterus myomatosus diskutiert. mifepriston überschreitet die plazenta und beeinflusst tierexperimentell nicht die konzentration an fetalem progesteron, estradiol oder cortisol. nur die aldosteronkonzentration scheint anzusteigen. bezüglich teratogenese sind die tierexperimentellen ergebnisse widersprüchlich. in einer fallserie mit etwa 70 schwangerschaften, die nach abbruchversuchen mit mifepriston ausgetragen wurden, beobachtete man verschiedene fehlbildungen, darunter 4 kinder mit klumpfuß (sitruk-ware 1998). eine spezifische teratogene wirkung lässt sich aus dieser publikation und aus anderen fallbeschreibungen, die mehrheitlich gesunde neugeborene umfassen (pons 1991 , lim 1990 ), nicht eindeutig ableiten. generell kann jedoch der missglückte versuch eines schwangerschaftsabbruchs die fetale entwicklung gefährden. empfehlung für die praxis: falls eine schwangerschaft nach vergeblicher anwendung von mifepriston ausgetragen wird, sollte eine ultraschallfeindiagnostik die normale organentwicklung bestätigen. ein risikobegründeter schwangerschaftsabbruch ist durch einen missglückten abortversuch nicht zwingend indiziert (siehe kapitel 1.15). g 2.15.20 clomifen pharmakologie und toxikologie. bei fehlender ovulation ohne hyperprolaktinämie wird seit über zwei jahrzehnten der estrogenantagonist clomifen (z. b. clomhexal ® , dyneric ® ) zur ovulationsauslösung eingesetzt. eine überdosierung, insbesondere in kombination mit hcg (humanes choriongonadotropin), kann zur überstimulierung der ovarien führen. zu den unerwünschten wirkungen zählen eine erhöhte rate an mehrlingsschwangerschaften und die vergrößerung der ovarien. die wirkung beruht offenbar auf einer kompetitiven besetzung der estrogenrezeptoren im hypothalamusbereich, die zu vermehrter lh-(luteinisierungshormon-)freisetzung führt. es gibt eine anhaltende diskussion darüber, ob clomifen fehlbildungen, wie z. b. neuralrohrdefekte, verursacht (van loon 1992). ein fallbericht beschreibt eine glaskörperanomalie bei einem kind, dessen mutter 100 mg clomifen bis woche 6 eingenommen hatte (bishai 1999) . in japan wurden 1.034 durch clomifen induzierte schwangerschaften über einen zeitraums von 5 jahren beobachtet. von den 935 lebend geborenen kindern wiesen 2,3 % fehlbildungen auf, eine gegenüber der kontrollgruppe nicht erhöhte rate (kurachi 1983) . allerdings wurde nicht differenziert, ob nur vor oder auch nach eintritt der schwangerschaft mit clomifen behandelt wurde. die fallsammlung eines herstellers ergab bei 2.379 clomifen-patientinnen 58 fehlbildungen (2,4 %). bei 158 frauen fand die clomifeneinnahme (auch) nach der konzeption statt, in dieser gruppe hatten 8 kinder (5,1 %) fehlbildungen. eine studie mit daten eines fehlbildungsregisters fand eine erhöhte inzidenz für kraniosynostosen bei 20 schwangeren, die clomifen vor oder während der schwangerschaft eingenommen hatten (reefhuis 2002) . eine weitere ähnliche konzipierte arbeit mit unbekannter fallzahl stellte signifikant häufiger penoskrotale hypospadien nach clomifen fest (meijer 2005) . ein erhöhtes individuelles risiko lässt sich jedoch mit den derzeit vorliegenden studienergebnissen nicht belegen. eythropoietine werden bei schwerer anämie, z. b. bei chronischen nierenerkrankungen und nach nierentransplantation, eingesetzt, aber auch bei krebs-und hiv-therapie, sowie bei thalassämie und bei therapieresistenter anämie in der schwangerschaft. rekombinantes humanes erythropoietin ist nicht plazentagängig und hat sich in einer reihe von berichten und fallserien als gut verträglich in der schwangerschaft erwiesen. ein nennenswertes risiko für den embryo/fetus besteht nicht. ob die in 4 schwangerschaften beschriebene schwere mütterliche hypertonie und verschlechterung der nierenfunktion der schwangeren auf die gabe von erythropoietin zurückzuführen ist, konnte nicht abschließend geklärt werden . zu darbepoetin alfa liegen weniger erfahrungen in der schwangerschaft vor als zu epoetin, jedoch wurden negative effekte bisher nicht beschrieben (goshorn 2005 (ebi 1994 , duncan 1986 , brodsky 1980 . einige untersucher beobachteten eine erhöhte abortrate nach narkosen, es ist aber schwierig, dies den narkosemitteln zuzuordnen. tierexperimentelle ergebnisse zu einzelnen substanzen sind aufgrund der hohen dosen und wiederholten anwendungen nicht auf klinische situationen einer anästhesie übertragbar. lokalanästhetika, die entweder gespritzt oder aufgesprüht werden, galten lange als mittel der wahl in der schwangerschaft, weil man annahm, dass sie am ort der applikation verbleiben und nicht zum fetus übergehen. doch auch diese form der anästhesie schließt komplikationen nicht aus, da auch lokalanästhetika je nach ort und durchblutung der injektionsstelle den fetus über den mütterlichen kreislauf erreichen können. im zusammenhang mit operativen eingriffen verwendete muskelrelaxanzien sind quartäre ammoniumpräparate, die unter physiologischen bedingungen stark ionisiert vorliegen und daher nur langsam die plazenta überschreiten. trotzdem kommt es zu einem nachweisbaren übergang auf den fetus. g 2.16.1 halogenierte inhalationsnarkotika pharmakologie und toxikologie. desfluran (suprane ® ), enfluran, halothan, isofluran (z. b. forene ® ) und sevofluran (sevorane ® ) gehören zu den halogenierten inhalationsnarkotika. in der perinatalphase ist zum einen ihre relaxierende wirkung am uterus zu beachten, die zur minderung der wehentätigkeit führen kann, und zum anderen ihr atemdepressiver effekt, vor allem bei risikogeburten. halothan ist eines der ältesten und am weitesten verbreiteten halogenierten inhalationsnarkotika. teratogene wirkungen beim menschen sind nicht bekannt. im tierversuch haben sich dagegen skelett-und andere anomalien, minderwuchs, verhaltensabweichungen und absterben der frucht gezeigt. diese auffälligkeiten wurden bei der üblichen anwendung beim menschen nicht beobachtet. bei gabe von halothan um den geburtstermin (z. b. sectionarkosen) muss mit einer verstärkten uterusrelaxation, einer erhöhten blutungsgefahr sowie mit einer atemdepression des neugeborenen gerechnet werden. unter den volatilen anästhetika hat halothan die stärkste kreislaufdepressorische wirkung. hohe dosen können herzrhythmusstörungen und herzstillstand verursachen, besonders wenn zusätzlich § -sympathomimetische tokolytika oder katecholamine eingesetzt werden. über lebertoxizität wurde bei wiederholungsnarkosen berichtet. enfluran ist ein fluorierter ether, der mit einer metabolisierungsrate von 2-5 % nur zu geringen teilen verstoffwechselt wird. die anwendung bei sectionarkosen wird vom neugeborenen gut vertragen (tunstall 1989 , abboud 1985 . tierexperimentell gibt es unter versuchsbedingungen, die sich grundlegend von der klinischen situation unterscheiden, teilweise embryotoxische effekte. teratogene wirkungen beim menschen sind nicht bekannt. enfluran wird wegen der gegenüber isofluran in fast allen bereichen ungünstigeren eigenschaften (anflutung, abflutung, kreislaufdepression, metabolisierungsrate) nur noch in wenigen zentren für narkosen benutzt. isofluran ist das strukturisomer von enfluran. es gehört mit einer metabolisierungsrate von nur 0,2 %, genau wie desfluran, zu den am wenigsten verstoffwechselten halogenierten inhalationsnarkotika. beilin und mitarbeiter (1999) desfluran weist von allen anästhesiemitteln den niedrigsten blut/gasund gewebe/blut-verteilungskoeffizienten auf sowie die geringste löslichkeit. es ist das am schwächsten wirksame narkosegas. desfluran wird von allen halogenierten inhalationsnarkotika am wenigsten verstoffwechselt, daher ist das toxische potenzial gering. wegen des schnellen einschlafens und angenehmen aufwachens der patienten wird desfluran häufig für sectionarkosen benutzt, ohne dass nachteile für die neugeborenen oder die mutter bekannt wurden. es gibt zwei fallberichte über maligne hyperthermie. teratogene wirkungen beim menschen sind nicht bekannt. die uterusrelaxierende wirkung ist abhängig von der anästhesietiefe, ähnlich wie bei den übrigen halogenierten inhalationsnarkotika. trotz des schnellen anflutens kann desfluran aufgrund seiner schwachen wirksamkeit nicht als einleitungsnarkotikum gewählt werden. die für eine narkose erforderlichen konzentrationen von mehr als 6 % würden die atemwege reizen und könnten dadurch zu atemanhalten führen. sevofluran ist ein weiteres halogeniertes anästhetikum, das als halogen nur fluorid enthält. aufgrund der physikalischen eigenschaften ist der anstieg im blut etwas langsamer als bei desfluran, aber schneller als bei allen anderen halogenierten inhalationsnarkotika. im gegensatz zu desfluran ist sevofluran als einleitungsnarkotikum gut geeignet. die metabolisierungsrate liegt bei 3-5 %. dadurch kommt es im blut zum anstieg von anorganischem fluorid und im atemkalk zur bildung von so genanntem compound a. beide substanzen haben zwar ein nephrotoxisches potenzial, erreichen aber keine schädigenden konzentrationen. sevofluran wird heute in vielen geburtshilflichen zentren als standardnarkotikum bei der sectio angewandt, ohne dass negative einflüsse auf das neugeborene beschrieben werden und auch teratogene wirkungen sind beim menschen nicht bekannt. empfehlung für die praxis: die halogenierten inhalationsnarkotika gehören in der geburtshilfe zu den standardnarkotika. sie können bei beachtung der möglichen charakteristischen nebenwirkungen während der gesamten schwangerschaft eingesetzt werden. bei anwendung unter der geburt sind uterusrelaxation und depressorische auswirkungen auf das neugeborene zu beachten. lachgas ist gegenüber den halogenierten inhalationsnarkotika ein gut verträgliches narkotikum, das weder deren negative wirkung auf das herz-kreislauf-system noch auf den uterus besitzt. unter der geburt kann durch die inhalation eines lachgas-sauerstoff-gemisches eine schnelle und einfache analgetische wirkung erzielt werden, die sich außerdem sehr gut steuern lässt. in seltenen fällen kann auch lachgas beim neugeborenen eine atemdepression hervorrufen, die eine beatmung erforderlich macht (langanke 1987) . umfangreiche studien über die anwendung von lachgas lassen bei über 1.000 schwangeren keine teratogenen effekte erkennen (crawford 1986 . andere studien thematisieren risiken bei der anwendung während der geburt. taylor und mitarbeiter (1993) stellten fest, dass höhere dosen von lachgas zu einem verzögerten geburtsverlauf führen. polvi und mitarbeiter (1996) fanden veränderungen im zerebralen gefäßwiderstand des kindes. diese beiden studien wurden jedoch kritisiert, weil sie nicht auf mögliche andere auslösende umstände eingehen. (herman 2000 , cordier 1992 ). aus diesem grunde gibt es obergrenzen für die belastung am arbeitsplatz. in den usa ist für lachgas eine maximal zulässige raumluftkonzentation von 25 ppm festgesetzt, in deutschland gelten noch 100 ppm als unbedenklich. eine korrekte einhaltung der maximal zulässigen belastung durch narkosegase ist in der praxis nur schwer möglich. kontrollmessungen müssen deshalb wiederholt durchgeführt werden. bei beruflich exponiertem anästhesie-und op-personal wurde über erhöhte abortraten berichtet, die auf die chronische exposition mit inhalationsnarkotika zurückgeführt wurden (hemminki 1985 , vessay 1980 . später ließ sich der verdacht in ausführlichen epidemiologischen studien nicht eindeutig bestätigen und begleitende faktoren wie stress, kaffeekonsum, rauchen und angespannte körperhaltung sowie vorbestehende abortneigung wurden als auslösende ursachen angenommen (rowland 1992 (rowland & 1995 . in verschiedenen studien wurden ein geringeres geburtsgewicht und ein kürzeres gestationsalter festgestellt (ericson 1979 , rosenberg 1978 , pharoah 1977 , cohen 1971 . die langzeitentwicklung im alter von 5 bis 13 jahren wurde von ratzon (2004) (z. b. trapanal ® ) . nach intravenöser injektion erreicht die konzentration eines injektionsnarkotikums sofort ihren maximalspiegel im blut, der dann wegen der rasch einsetzenden umverteilung und ausscheidung schnell wieder abfällt. die wirkung im gehirn setzt wegen des starken blutflusses kurzfristig ein und klingt mit der umverteilung schnell wieder ab. alle injektionsnarkotika passieren wegen ihrer hohen lipidlöslichkeit rasch die plazenta, werden aber vor erreichen des fetalen gehirns zunehmend im fetalen blut verdünnt und zum teil auch in der fetalen leber aufgenommen. daher bewirkt eine einmalige bolusinjektion eines nicht zu hoch dosierten injektionsnarkotikums keine anästhesie des fetus bzw. des neugeborenen, während nach wiederholten dosen mit einer depressorischen wirkung beim fetus gerechnet werden muss. die konzentration im neugeborenen ist bei anwendung unter der geburt umso geringer, je mehr zeit zwischen injektion des narkotikums und der geburt des kindes verstreicht. alle genannten injektionsnarkotika können während der schwangerschaft benutzt werden, sie werden nachfolgend einzeln vorgestellt. etomidat ist ein imidazolderivat, das durch unspezifische esterasen abgebaut wird. es führt zu einem extrem schnellen wirkungseintritt mit sehr raschem abklingen (halbwertszeit im serum 3 minuten). die kurze wirkdauer beruht ähnlich wie bei den barbituraten auf umverteilung vom gut durchbluteten gehirn in schlechter durchblutete große gefäßgebiete, nämlich muskel-und fettgewebe (lipophilie). etomidat besitzt keine kardiodepressorischen eigenschaften, kann aber zu myo-kloni und dyskinesien führen und wirkt hemmend auf die nebennierenrindenfunktion. ketamin ist ein rasch wirkendes injektionsnarkotikum, das eine gute analgetische wirkung besitzt und die atmung kaum beeinflusst. es gibt keine studien zur beeinflussung der fetalen entwicklung beim menschen. aufgrund einer verstärkung der empfindlichkeit gegenüber sympathikomimetika führt es zu deutlichen kardiovaskulären effekten, wie z. b. anstieg von herzfrequenz und blutdruck. ketamin stimuliert dosisabhängig den tonus und die wehenfrequenz des uterus und darf bei uteriner hyperaktivität und drohender fetaler hypoxie nicht eingesetzt werden. hohe dosen können fetale funktionen beeinträchtigen und ein erweitertes monitoring unter der geburt erforderlich machen (barak 1990 , reich 1989 . ketamin führt bei kaiserschnittentbindungen zu teilweise therapiebedürftigen angstzuständen in folge von horrorvisionen, was den einsatz trotz seiner guten analgetischen eigenschaften stark limitiert. ketamin s wird eine in dieser hinsicht bessere verträglichkeit zugeschrieben. propofol ist in nordamerika heute das neben thiopental am meisten angewandte injektionsnarkotikum in der schwangerschaft. als einleitungssubstanz stellt es eine geeignete alternative zu thiopental dar (richardson 1991 . für die intubation zeichnet sich propofol durch einen raschen bewusstseinsverlust aus. die kurze aufwachzeit und die geringen nebenwirkungen sind von großem vorteil für die schwangere patientin. nach injektion überwindet propofol die plazenta rasch, die fetalen blutkonzentrationen entsprechen etwa 70 % der mütterlichen werte (jauniaux 1998 , dailland 1989 . propofol wird rasch aus dem kreislauf des neugeborenen entfernt (dailland 1990 , moore 1989 , valtonen 1989 . in klinischen untersuchungen fand sich bei einleitung zur sectio mit propofol mit 2-2,8 mg/kg kg im vergleich mit 4-5 mg/kg kg thiopental kein unterschied in den apgar-werten, den säure-basen-parametern und dem neurologischen zustand des neugeborenen (d' alessio 1998). in einer studie, die den enns (early neonatal neurobehavioral scale) benutzte (d'alessio 1998 , celleno 1989 , wurde bei neugeborenen nach sectionarkose mit propofol im vergleich zu thiopental ein ungünstigeres ergebnis bei einigen neurologischen funktionen nachgewiesen. diese effekte zeigen sich aber nur zeitlich begrenzt. gin und mitarbeiter (1990 b) fanden dagegen, dass propofol dem thiopental als einleitungsnarkotikum zur sectio überlegen war. blutdruckabfälle waren nicht häufiger zu beobachten als nach thiopental. wird die gewinnung von eizellen bei der in-vitro-fertilisation (ivf) in propofol-narkose vorgenommen, so hat dies keinen negativen effekt auf den schwangerschaftserfolg (beilin 1999 , christiaens 1998 ). thiopental-natrium ist ein thiobarbiturat, das sich durch schnellen wirkungseintritt auszeichnet. die kurze wirkdauer ist durch umverteilung bedingt. anfangs reichert sich das medikament wegen der guten durchblutung im gehirn an. die anschließende umverteilung in das muskel-und fettgewebe lässt die konzentration im gehirn rasch unter die narkotisch wirksame schwelle abfallen. da thiobarbiturate den uterustonus und die wehentätigkeit nicht beeinflussen, bleibt nach der geburt die kontraktionsfähigkeit des uterus erhalten. außerdem wurden keine interaktionen mit g -sympathikomimetika beschrieben. thiobarbiturate lassen sich bereits eine minute nach injektion im fetalen blut nachweisen. die konzentration liegt dabei nur gering unter der im mütterlichen blut. während der geburt ist bei niedriger dosierung (i.v. bis 5 mg/kg kg) keine beeinträchtigung des fetus zu erwarten. bei höherer dosierung muss mit einer atemdepression beim neugeborenen gerechnet werden (langanke 1987 generell werden lokalanästhetika in allen phasen der schwangerschaft jedoch gut vertragen. sie scheinen keine anhaltenden auswirkungen auf die neurophysiologie des neugeborenen zu haben. es wurden keine teratogenen schäden nach einsatz im 1. trimenon beobachtet. lidocain, das am häufigsten eingesetzte lokalanästhetikum, hat wegen des niedrigen pka-wertes (7,7 bis 7,8) einen schnellen wirkungseintritt und überschreitet leicht die plazenta. ein negativer einfluss auf die schwangerschaft ist nicht bekannt. in einer studie mit mehr als 1.200 schwangeren fand sich keine zunahme der fehlbildungsrate . lidocain wird auch in der geburtshilflichen periduralanästhesie eingesetzt. es lindert den geburtsschmerz, ohne die wehenstärke oder die mitarbeit der gebärenden wesentlich zu beeinträchtigen. auch bei dieser anwendung gibt es einige wenige berichte über negative auswirkungen. sie betreffen zeitlich begrenzte veränderungen der fetalen kardiopulmonalen anpassung (bozynski 1987) , veränderungen von evozierten potenzialen im stammhirn (bozynski 1989) und temperaturregulationsstörungen mit hyperthermie nach mehrstündiger epiduralanalgesie (macaulay 1992) . in einigen studien wurde die periduralanästhesie mit veränderungen des verhaltens beim neugeborenen in zusammenhang gebracht. neuere studien haben jedoch gezeigt, dass solche veränderungen selten und nur vorübergehend sind (decocq 1997 , fernando 1997 . bupivacain ist das zurzeit am häufigsten verwendete lokalanästhetikum in der geburtshilfe. es hat eine starke wirkung und ausgeprägte zentralnervöse und kardiotoxische nebenwirkungen, die in der schwangerschaft zusätzlich durch progesteron verstärkt werden. bupivacain kann zu einem reentry-phänomen mit auslösung ventrikulärer tachykardien und kammerflimmern führen. die rate an toxischen wirkungen konnte deutlich gesenkt werden, nachdem das 0,75 %ige bupivacain in der geburtshilfe nicht mehr angewandt wurde. der hauptvorteil dieser substanz liegt in der langen wirkdauer (3-10 stunden). besonders in geringen konzentrationen kommt es eher zur sensorischen als zur motorischen blockade. wegen der hohen eiweißbindung ist die plazentapassage gering. ropivacain ist ein lokalanästhetikum vom amidtyp mit einer dem bupivacain vergleichbaren pharmakokinetik und pharmakodynamik. die vorzugsweise sensorische blockade ist noch ausgeprägter als bei bupivacain. dennoch hat sich bei ropivacain im vergleich zu bupivacain bisher kein vorteil hinsichtlich geringerer inzidenz motorischer blockaden (die eine instrumentelle entbindung notwendig machen) bei gleicher anästhesiequalität nachweisen lassen (eddleson 1996) . toxische und zentralnervöse nebenwirkungen treten bei ropivacain im vergleich mit bupivacain erst bei einer höheren gesamtmenge an verabreichtem lokalanästhetikum auf (santos 1995) . die austestung einer minimal lokalanästhetischen konzentration (mlac) konnte nachweisen, dass die anästhetische potenz von ropivacain um 30 % geringer ist als die von bupivacain. ein zusatz von opioiden zu epidural verabreichten lokalanästhetika bietet den vorteil eines schnelleren wirkungseintritts, einer verbesserten analgesie und einer reduktion des bedarfs an lokalanästhetika. dadurch kann die rate an motorischen blockaden und instrumentellen entbindungen gesenkt werden. bei rückenmarksnahen regionalanästhesieverfahren werden lipophile opioide wie sufentanil und fentanyl bevorzugt, da sie schnell am applikationsort aufgenommen werden, und dadurch die analgesie regional begrenzt bleibt. das risiko einer späteren atemdepression kann aufgrund einer kürzeren liquorverweildauer gesenkt werden. andere opioidbedingte nebenwirkungen, wie übelkeit und erbrechen, atemdepression und pruritus, treten seltener auf (gogarten 1997) . lipophile opioide wie sufentanil werden jedoch leichter in das gefäßsystem aufgenommen und können in signifikanten konzentrationen im plasma nachgewiesen werden. beim vergleich von fentanyl mit sufentanil führt letzteres zur besseren schmerzausschaltung und reichert sich trotz einer nachweisbaren plazentapassage weniger ausgeprägt im neugeborenen an (loftus 1995) . eine gesamtdosis von 30 ? g sufentanil epidural führt nicht zu einer klinisch relevanten neonatalen beeinträchtigung (siehe auch kapitel 2.1). empfehlungen für die praxis: lokalanästhetika dürfen auch in der schwangerschaft zur infiltrations-und leitungsanästhesie eingesetzt werden. das gilt auch für präparate mit adrenalinzusatz. bewährte vertreter dieser gruppe, wie z. b. in der geburtshilfe bupivacain, sind zu bevorzugen. prilocain ist wegen des vergleichsweise hohen risikos der methämoglobinbildung zu meiden. g 2.16.7 muskelrelaxanzien pharmakologie und toxikologie. muskelrelaxanzien werden immer dann in der narkose eingesetzt, wenn sich durch narkotika allein keine ausreichende erschlaffung der skelettmuskulatur erreichen lässt. alcuronium (alloferin ® ), atracurium (tracrium ® ), cisatracurium (nimbex ® ), mivacurium (mivacron ® ), pancuronium (pancuronium duplex ® ), rocuronium (esmeron ® ) und vecuronium (norcuron ® ) gehören wie tubocurarin zu den kompetitiv hemmenden muskelrelaxanzien. im gegensatz zu den narkotika und lokalanästhetika passieren muskelrelaxanzien wegen ihres hohen dissoziationsgrades und ihrer geringen lipidlöslichkeit die blut-hirn-schranke und auch die plazenta nur in geringem ausmaß. im nabelschnurblut bzw. im fetalen gewebe erreichen sie deshalb nur etwa 10 % der bei der mutter gemessenen konzentration. die übertragenen konzentrationen reichen nicht aus, um beim fetus eine relaxierende wirkung hervorzurufen. es gibt jedoch einen fallbericht über eine zehn stunden anhaltende neugeborenenparalyse nach gabe von 245 mg d-tubocurarin zur behandlung eines status epilepticus bei der mutter (lusso 1993) und über eine an tierexperimentelle beobachtungen erinnernde arthrogrypose beim kind nach behandlung eines mütterlichen tetanus mit tubucurarin über 2,5 wochen am ende des 1. trimenons (jago 1970) . teratogene eigenschaften wurden bisher nicht beobachtet. insbesondere pancuronium hat sich in der geburtshilfe bewährt. bei einer dosierung von 0,03 mg/kg wurden bei 800 schnittentbindungen keine nebenwirkungen an den neugeborenen beobachtet (langanke 1987) . es kann auch zur relaxierung des fetus bei intrauteriner transfusion benutzt werden (moise 1987) . atracurium soll pancuronium bei der direkten relaxation des fetus überlegen sein, wenn dieser wegen einer anämie für eine intrauterine transfusion vorbereitet werden soll (mouw 1999) . in einer anderen untersuchung werden vorteile des vecuroniums bei dieser anwendung beschrieben. einschränkungen der fetalen herzfrequenz sollen geringer als bei pancuronium sein (watson 1996) . suxamethonium (succinylbischolin; lysthenon ® , pantolax ® ) ist ein depolarisierendes muskelrelaxans, das durch die plasmacholinesterase schnell abgebaut wird. fand bei 26 kindern, deren mütter während der schwangerschaft mit succinylcholin behandelt worden waren, keine anomalien. vorübergehende atemdepression bei neugeborenen wurde vereinzelt nach succinylcholinbehandlung unter der geburt beschrieben. bei ca. 3-4 % der bevölkerung ist die plasmacholinesterase erniedrigt. zusätzlich verringert sich die aktivität dieses enzyms am ende der schwangerschaft um bis zu 30%. bei diesen patientinnen kann es nach succinylcholingabe zur verlängerung der wirkung und auch zur apnoe beim neugeborenen kommen (cherala 1989) . solche komplikationen sollten durch anwendung der niedrigsten effektiven dosis vermieden werden. succinylcholin kann bereits bei dosen von 1 mg/kg den tonus des uterus erhöhen oder die wehentätigkeit stimulieren. dieser unerwünschte effekt ist bei drohender fetaler hypoxie zu beachten. mivacurium (mivacron ® ) ist ein kurz wirkendes, nicht depolarisierendes muskelrelaxans, das ebenso wie succinylcholin durch plasmacholinesterase abgebaut wird. wegen der häufig kurzen op-zeiten bei kaiserschnitt bietet es sich als muskelrelaxans an, führt aber bei einem mangel an plasmacholinesterase ebenso wie succinylcholin zur verlängerung der wirkdauer. völlig andere indikationen haben präparate mit clostridium botulinum toxin (botox ® , dysport ® ), die beim blepharospasmus und anderen fokalen spastizitäten sowie bei primärer hyperhidrosis appliziert werden. systematische untersuchungen zur schwangerschaft liegen nicht vor. anaphylaktoide reaktionen sind nicht auszuschließen (siehe auch botulismus in abschnitt 2.22). empfehlung für die praxis: im rahmen der narkose dürfen die üblichen muskelrelaxanzien (pancuronium, suxamethonium) in der schwangerschaft eingesetzt werden, dabei sollten möglichst niedrige dosierungen gewählt werden. clostridium botulinum toxin sollte in der schwangerschaft nicht verabreicht werden, da es sich nicht um eine vitale indikation handelt. eine dennoch erfolgte exposition erfordert keine konsequenzen, wenn die mutter keine nennenswerten nebenwirkungen hatte. in diesem abschnitt werden die wichtigsten arzneimittel in der dermatologie sowie andere häufig verwendete lokaltherapeutika behandelt. weitergehende informationen zu einzelnen arzneimitteln finden sich unter den substanzbegriffen in anderen abschnitten. vaginaltherapeutika siehe kapitel 2.14.11. g 2.17.1 schwangerschaftstypische veränderungen an der haut die umstellung des organismus in der schwangerschaft führt an der haut zu typischen morphologischen und funktionellen veränderungen. sie sind völlig normal und müssen nicht behandelt werden. dazu gehören: zur lokalen therapie mit neomycin gibt es 12 prospektiv erfasste fälle, davon 7 mit exposition im 1. trimenon. über fehlbildungen wurde nicht berichtet. zu den ausschließlich lokal angewandten antibiotika framycetin (leukase ® ), meclocyclin (meclosorb ® creme), mupirocin (z. b. turixin ® salbe), nadifloxacin (nadixa ® creme), neomycin (z. b. nebacetin ® ) und tyrothricin (z. b. tyrosur ® gel) liegen keine ausreichenden erfahrungen vor. für kein antibiotikum in äußerlicher anwendung hat sich bisher ein verdacht auf teratogene effekte ergeben. mittel, die systemisch unbedenklich sind, können, falls sinnvoll, auch für die lokale therapie eingesetzt werden (siehe auch kapitel 2.6). siehe abschnitt 2.6.34 und folgende. bei topischer anwendung hat sich bisher für kein virustatikum ein verdacht auf teratogene effekte ergeben. dies gilt auch für das virustatikum aciclovir (z. b. zovirax ® ). generell ist die lokale antivirale therapie von herpes-simplex-infektionen wegen möglicher resistenzentwicklungen nicht zu empfehlen. besser geeignet scheinen austrocknende maßnahmen oder falls indiziert, eine systemische therapie. im eigenen datenbestand finden sich bei 35 prospektiv erfassten schwangerschaften mit lokaler aciclovir-therapie, 21 davon mit exposition im 1. trimenon, keine hinweise auf entwicklungstoxische schäden. auch die wesentlich umfangreicheren erfahrungen mit der systemischen anwendung von aciclovir haben kein risiko für das ungeborene erkennen lassen (siehe abschnitt 2.6.52). auch die lokale behandlung von condylomata acuminata (feigwarzen) mit podophyllotoxin (z. b. condulox ® , wartec ® ), einem pflanzlichen mitosehemmstoff , bargman 1988 , hat keine hinweise auf teratogenität ergeben (eigene daten). systematische untersuchungen liegen allerdings nicht vor. über insgesamt 8 schwangere mit einer äußerlichen therapie mit dem immunmodulator bzw. virustatikum imiquimod (aldara ® ) wegen condylomata acuminata oder anderer warzen, davon 2 im 1. trimenon, wird berichtet. alle wurden von gesunden kindern entbunden (einarson 2006 , maw 2004 . von 5 eigenen prospektiv ausgewerteten schwangerschaften mit lokaler imiquimodtherapie endeten 2 mit einem spontanabort. bei den 3 lebendgeborenen wurden keine fehlbildungen beobachtet. zu den vorwiegend lokal eingesetzten virustatika foscarnet-natrium (z. b. triapten ® ), idoxuridin (z. b. virunguent ® ), penciclovir (vectavir ® ), tromantadin (viru-merz ® ) und vidarabin liegen keine ausreichenden erfahrungen vor. virustatika, die in der schwangerschaft systemisch angewendet werden dürfen, sind in der regel auch als lokaltherapeutika unproblematisch (siehe kapitel 2.6.52 bis 2.6.55). (weber 1998) . hinweise auf teratogene effekte bei vaginaler anwendung in der schwangerschaft haben sich in einer retrospektiven vergleichenden untersuchung von fehlgebildeten und gesunden kindern nach mütterlicher povidon-iod-exposition nicht ergeben sagrotan ® ; triclosan, z. b. in sicorten plus ® ) sind in der schwangerschaft als relativ sicher anzusehen. sie sollten in einer konzentration von nicht mehr als 2 % und nur an der unverletzten haut angewendet werden. bei höheren konzentrationen muss mit relevanter resorption gerechnet werden. chlorhexidin (z. b. lemocin cx ® ) ist bei schwangeren zur desinfektion von haut und schleimhäuten geeignet. es hat sich zur desinfektion der scheide bei geburten und des abdomens beim kaiserschnitt bewährt (übersicht in . mit dem neurotoxischen phenolderivat hexachlorophen ist dagegen zurückhaltung in der schwangerschaft angezeigt, da bei behandlung größerer flächen und mit konzentrationen von mehr als 3 % resorptive vergiftungsbilder mit zns-symptomatik bei den behandelten patienten beobachtet wurden. in einigen tierexperimentellen studien hat sich hexachlorophen als teratogen gezeigt. in den letzten jahrzehnten wurde in mehreren publikationen der berufliche kontakt mit hexachlorophen kontrovers bezüglich möglicher fetotoxischer wirkungen diskutiert. eine ältere untersuchung an 3.000 gewerblich exponierten schwangeren fand keine auffälligkeiten (baltzar 1979), eine weitere retrospektive untersuchung postulierte einen zusammenhang zwischen mentaler entwicklungsretardierung und beruflicher exposition im letzten schwangerschaftsdrittel (roeleveld 1993 pharmakologie und toxikologie. quecksilber kann aus zubereitungen zur äußeren anwendung (früher in mercuchrom ® ) quantitativ resorbiert werden und ist potenziell entwicklungstoxisch (lauwerys 1987 pharmakologie und toxikologie. calcipotriol (z. b. psorcutan ® ) ist ein vitamin-d 3 -derivat, das zur therapie der psoriasis sowohl extern als auch intern angewendet wird. es führt zur reduktion der keratinozytenproliferation und hat auch immunmodulatorische funktionen. grundsätzlich ist in der schwangerschaft eine d-hypervitaminose zu vermeiden. anwendungen im empfohlenen dosisbereich ( p 100 g/woche einer 0,005 %igen zubereitung) führen aber nach heutigem wissen nicht zu einer störung des calcium-stoffwechsels. systematische untersuchungen zur pränataltoxizität beim menschen fehlen zu calcipotriol ebenso wie zu dithranol (z. b. micanol ® ), das als antimitotische substanz in der schwangerschaft theoretisch suspekt ist, obwohl eine quantitative resorption der üblicherweise 1-3 %igen zubereitungen nicht wahrscheinlich ist. zu dem ausschließlich lokal angewendeten vitamin-d-derivat tacalcitol (z. b. curatoderm salbe ® ) liegen keine ausreichenden erfahrungen zur anwendung in der schwangerschaft vor. es ist ähnlich zu bewerten wie calcipotriol. g 2.17.10 retinoide zur akne-und psoriasistherapie pharmakologie. isotretinoin (13-cis-retinsäure; roaccutan ® , isotrex-gel ® ) und tretinoin (all-trans-retinsäure; z. b. cordes ® vas, vesanoid ® ) sind natürliche derivate des vitamin a (retinol). sie werden bei äußerlicher und systemischer anwendung seit über 20 jahren mit großem erfolg bei akne eingesetzt. tretinoin ist außerdem in systemischer zubereitung zur behandlung der promyelozytären leukämie zugelassen. retinsäure ist ein körpereigener wachstumsfaktor, der in allen zellen vorkommt und an spezifische retinoidrezeptoren gebunden wird. eine besonders wichtige funktion hat die retinsäure während der embryonalphase, da sie u. a. die entwicklung von gehirn und wirbelsäule steuert. retinoide stimulieren die proliferation epidermaler zellen, an der haut lockern sie die hornschicht auf und begünstigen auf diese weise die hautabschilferung. isotretinoin führt zusätzlich zur atrophie der talgdrüsen. diese eigenschaften erklären die wirksamkeit in der aknetherapie. die halbwertszeit von isotretinoin und seinem metaboliten 4-oxo-isotretinoin beträgt durchschnittlich 29 bzw. 22 stunden, im extremfall bis zu einer woche (nulman 1998) . bei der behandlung der psoriasis haben sich acitretin (neotigason ® ) und das inzwischen aus dem handel genommene etretinat (tigason ® ) bewährt. beide führen zu lang anhaltend hohen retinoidkonzentrationen im körper. dabei wird acitretin zu etretinat metabolisiert, dessen halbwertszeit 80-175 tage beträgt. alkoholgenuss steigert die umwandlung zu etretinat (larsen 2000) . zu den synthetischen, polyaromatischen, rezeptorselektiven retinoiden gehören adapalen (differin ® ), das zur therapie einer schweren acne vulgaris eingesetzt wird und tazaroten (zorac ® ) zur behandlung der psoriasis. für die topische behandlung eines aids-assoziierten kaposi-sarkoms steht als neue substanz 0,1 %iges alitretinoin-gel (panretin ® ) zur verfügung, das durch aktivierung von retinoidrezeptoren das wachstum von tumorzellen hemmen soll. toxikologie. die ausgeprägten teratogenen eigenschaften der retinoide waren vor der markteinführung tierexperimentell bekannt. retinoide sind heute die beim menschen am stärksten teratogen wirksamen arzneimittel seit thalidomid (contergan ® ). ihre anwendung in der schwangerschaft erhöht das spontanabortrisiko und führt zum charakteristischen retinoid-syndrom: fehlanlage der ohren einschließlich agenesie oder stenose des gehörgangs, störungen der gesichts-und gaumenbildung, mikrognathie, kardiovaskuläre defekte und entwicklungsstörungen im bereich des thymus und des zns, die von neurologischen schäden mit beteiligung von augen und innenohr bis zum hydrozephalus reichen (lammer 1988 (lammer und 1985 . intelligenzdefizite wurden auch bei kindern ohne erkennbare fehlbildungen beobachtet (adams 1991). prospektive studien zur mütterlichen einnahme von isotretinoin in der schwangerschaft ergaben bis zu 40 % spontanaborte, vermehrt frühgeburten und bis zu 35 % große fehlbildungen. nachuntersuchungen der intrauterin mit retinoid exponierten kinder im alter von 5-10 jahren fanden eine hohe rate an mentalen retardierungen und speziellen schwächen bei der visuell-räumlichen verarbeitung. bei 25 % der kinder mit intelligenzdefekten wurden keine großen fehlbildungen diagnostiziert (adams 2004). vor allem in nordamerika wurden durch isotretinoin geschädigte kinder geboren, obwohl wissenschaftliche fachgesellschaften eindringlich auf das teratogene risiko hingewiesen hatten, wie z. b. die teratology society der usa (1991). offenbar funktionierte die vorgeschriebene aufklärung in vielen fällen nicht ausreichend . an hersteller und fda wurden bis zum jahre 2000 über 150 fälle gemeldet. zahlreiche publikationen berichten über einzelfälle oder kleine fallserien, wie z. b. 14 in kalifornien erfasste schwangerschaften, von denen 5 mit einem schwangerschaftsabbruch endeten, 4 mit einem spontanabort und 5 mit lebendgeburten. eines der kinder wies die bekannten fehlbildungen auf, bei den anderen 4 kindern waren keine nachweisbar . moericke (2002) beschreibt 2 feten nach schwangerschaftsabbruch, die zwar keine äußeren fehlbildungen aufwiesen, jedoch mittel-und innenohranomalien. neben früheren fallberichten zu multiplen fehlbildungen bei acitretin (z. b. de die-smulders 1995) wurde kürzlich ein weiterer fallbe-richt mit täglich 10 mg bis woche 10 und typischer embryopathie (mikrozephalie, fasziale dysmorphien, vorhofseptumdefekt, bilaterale sensorineurale taubheit) publiziert. im alter von 18 monaten hatte das kind eine persistierende mikrozephalie sowie eine neurologische entwicklungsretardierung (barbero 2004) . geiger und mitarbeiter (1994) berichteten über insgesamt 8 schwangerschaften mit acitretin, von denen 2 mit schwangerschaftsabbruch, 4 mit spontanabort und weitere 2 mit einer lebendgeburt endeten. einer der abortierten feten wies typische fehlbildungen auf. die beiden lebendgeborenen waren gesund, lediglich bei einem der kinder waren hörstörungen bei hohen frequenzen auffällig. von 67 schwangerschaften mit präkonzeptioneller acitretin-behandlung (im mittel 5 monate vor der konzeption) endeten 9 mit spontanabort, 18 mit schwangerschaftsabbruch und 40 mit einer lebendgeburt. vier kinder wiesen unspezifische fehlbildungen auf. bei 75 frauen mit etretinat-therapie in der schwangerschaft wurde über 29 lebendgeborene berichtet, von denen 6 retinoidtypische und 3 unspezifische fehlbildungen aufwiesen. unter den 41 schwangerschaftsabbrüchen fanden sich 5 feten mit retinoidspezifischen und 2 mit anderweitigen fehlbildungen, weitere 5 schwangerschaften endeten mit einem spontanabort. unter 88 lebendgeborenen von insgesamt 173 fällen mit einer etretinat-therapie vor der schwangerschaft (im mittel 15 monate vor konzeption) waren bei 5 kindern typische, bei 13 weiteren unspezifische fehlbildungen nachweisbar. auch bei 3 schwangerschaftsabbrüchen wurden retinoidspezifische fehlbildungen diagnostiziert (geiger 1994) . in postmarketing-studien wurden 11 fälle einer acitretin-behandlung zum zeitpunkt der konzeption beim vater erfasst. fünf schwangerschaften endeten mit der geburt gesunder kinder, 5 mit einem spontanabort und 1 mit einem schwangerschaftsabbruch (geiger 2002) . äußerliche anwendung. fünf fallbeschreibungen haben in den letzten jahren den verdacht aufkommen lassen, dass auch nach topischer applikation von tretinoin vitamin-a-säure-typische fehlbildungen nicht sicher auszuschließen sind (selcen 2000 , colley 1998 , navarre-belhassen 1998 , lipson 1993 , camera 1992 . zwei kontrollierte studien mit insgesamt etwa 300 schwangeren erbrachten hingegen keine hinweise auf teratogene effekte (shapiro 1997 , jick 1993 . die größere dieser studien beruht jedoch auf verordnungsprotokollen, von denen nicht zwingend auf eine tatsächlich erfolgte anwendung der mutter geschlossen werden kann. außerdem erlauben design und fallzahlen dieser studien noch nicht die annahme einer unbedenklichkeit (martinez-frias 1999) . eine neuere prospektive studie mit 106 im 1. trimenon äußerlich mit tretinoin behandelten frauen ergab weder ein erhöhtes abort-noch ein erhöhtes fehlbildungsrisiko. es fanden sich auch keine hinweise auf eine erhöhte inzidenz von retinoidverdächtigen kleinen anomalien im vergleich zu einer kontrollgruppe. die studie gibt allerdings keine angaben zur dosis und häufigkeit der lokalen tretinoinbehandlung (loureiro 2005) . im eigenen datenbestand haben wir 30 schwangerschaften mit lokaler tretinointherapie im 1. trimenon prospektiv erfasst. bis auf einen abort endeten alle schwangerschaften mit einer lebendgeburt. grobstrukturelle fehlbildungen wurden nicht beobachtet. auch aufgrund pharmakokinetischer daten ist ein nennenswertes teratogenes risiko bei äußerlicher anwendung nicht wahrscheinlich, wenn die behandelte fläche nicht allzu groß ist: die resorptionsquote beträgt durchschnittlich 2 % und maximal etwa 6 % (van hoogdalem 1998), die konzentration der topischen retinoidpräparate liegt bei 0,05 %, ein nennenswerter anstieg der endogenen retinoidkonzentrationen im plasma (2-5 ? g/l) nach äußerer anwendung wurde nicht beobachtet. übliche tägliche dosen sind maximal 2 g salbe, die 1 mg wirkstoff enthalten (0,05 %ig). allerdings muss bedacht werden, dass stark entzündete haut oder zusätzliche (desinfizierende) anwendungen (z. b. mit benzoylperoxid; siehe dort) die resorptionsquote erhöhen können. das bfarm (bundesinstitut für arzneimittel und medizinprodukte) warnt vor der äußerlichen applikation von tretinoin in der schwangerschaft (bfarm 1994). eine topische anwendung von isotretinoin (isotrex-gel ® ) ist genauso wie tretinoin zu bewerten. eigene daten zur lokalen isotretinoin-anwendung umfassen 23 prospektiv erfasste schwangerschaften. nur eines von 18 lebendgeborenen wies eine fehlbildung (gaumenspalte) auf. zur topischen anwendung von adapalen (differin ® ) gibt es einen fallbericht mit therapie bis woche 13, bei dem die schwangerschaft nach sonographischer diagnose zerebraler und okulärer fehlbildungen, die als nicht retinoidtypisch bewertet wurden, abgebrochen wurde (autret 1997). im eigenen datenbestand haben wir 6 prospektiv dokumentierte schwangerschaften mit adapalentherapie im 1. trimenon, die alle mit der geburt eines gesunden kindes endeten. in einer französischen prospektiven studie wurden 94 schwangerschaften mit topischer retinoidtherapie (tretinoin, isotretinoin oder adapalen) ausgewertet, dabei zeigte sich weder ein hinweis auf ein erhöhtes abortrisiko, noch war ein teratogenes risiko nachweisbar (carlier 1998) . allerdings wird weder nach substanzen differenziert, noch gibt es angaben zu zeitpunkt und dauer der therapie. bei lokaler anwendung von tazaroten (zorac ® ) werden 6 % der applizierten dosis perkutan resorbiert. es hat eine halbwertszeit von 17-18 stunden. seine metaboliten sind hydrophil, so dass keine anreicherung im fettgewebe stattfindet. nach behandlung in der schwangerschaft wurde über gesunde kinder berichtet, allerdings ohne angaben zu therapiedauer und dosis (menter 2000) . wir überblicken 5 prospektiv erfasste schwangerschaften mit therapie im 1. trimenon, von denen 2 mit einem spontanabort und 3 mit der geburt eines lebenden kindes endeten, ein neugeborenes wies ein kleines hämangiom auf. bei den anderen beiden fanden sich keine auffälligkeiten (eigene daten). zu alitretinoin-gel (panretin ® ) liegen keine erfahrungen in der schwangerschaft vor. empfehlung für die praxis: die systemische therapie mit den retinoiden acitretin, etretinat, isotretinoin und tretinoin ist in der schwangerschaft absolut kontraindiziert. bei frauen im gebärfähigen alter ist eine behandlung nur bei ausreichendem kontrazeptivem schutz und nach ausschluss einer schwangerschaft erlaubt, wenn andere therapieansätze wirkungslos waren. eine sichere kontrazeption muss nach absetzen von acitretin und etretinat noch zwei jahre weitergeführt werden und nach absetzen von isotretinoin noch einen monat. bei deutlichem unterschreiten dieser zeitvorgaben, insbesondere bei behandlung in die frühschwangerschaft hinein, ist eine erhebliche schädigung der embryonalen entwicklung möglich. nach eingehender analyse im einzelfall muss eventuell ein schwangerschaftsabbruch erörtert werden. die äußerliche anwendung von retinoiden ist während der schwangerschaft ebenfalls kontraindiziert. im fall einer solchen therapie in der frühschwangerschaft ist ein risikobegründeter schwangerschaftsabbruch (siehe kapitel 1.15) aufgrund des offenbar nur geringen, wenn überhaupt vorhandenen teratogenen risikos nicht inidiziert. eine ultraschallfeindiagnostik sollte jedoch angeboten werden. g 2.17.11 photochemotherapie und fumarsäure-präparate pharmakologie und toxikologie. die photochemotherapie (puva-therapie) der schwer verlaufenden psoriasis erfolgt mit oraler gabe oderheute bevorzugt -äußerer anwendung von 8-methoxy-psoralen (methoxsalen; meladinine ® ) und anschließender langwelliger uva-bestrahlung. durch das uv-licht wird das psoralen chemisch aktiviert, bindet stärker an dns und schädigt die zellen. der zytotoxische effekt der puva-behandlung ist aufgrund der geringen eindringtiefe des uv-lichtes auf die haut beschränkt. das european network of teratology information services entis hat 41 schwangerschaften analysiert, bei denen die systemische puva-therapie mit 8-methoxypsoralen durchgeführt wurde (garbis 1995) . in dieser studie, in der sich die puva-therapie auf das 1. trimenon beschränkte, fanden sich ebenso wie in einer skandinavischen studie (gunnarskog 1993) keinerlei hinweise auf embryotoxische effekte. fumarsäure wird in geringen mengen auch bei der nahrungsherstellung z. b. als antioxidanz verwendet, in der psoriasis-therapie sind hingegen nach einschleichen dosierungen von täglich einigen 100 mg üblich, die als nebenwirkungen u. a. leuko-und lymphopenien verursachen können. die verträglichkeit für den fetus wurde nicht untersucht. wir überblicken 15 schwangerschaften, bei denen in das 1. trimenon hinein eine psoriasis mit fumarsäure (dimethylfumarat + ethylhydrogenfumarat; fumaderm ® ) behandelt wurde. hinweise auf embryotoxische oder teratogene effekte haben sich dabei nicht ergeben (1 spontanabort, 1 totgeburt, bei den 13 lebend geborenen kindern fanden sich keine großen fehlbildungen). empfehlung für die praxis: die photochemotherapie mit 8-methoxypsoralen und uva-bestrahlung ist in der schwangerschaft wegen möglicher mutagener wirkungen kontraindiziert, auch eine fumarsäure-behandlung sollte unterbleiben. eine dennoch erfolgte anwendung rechtfertigt weder einen risikobegründeten schwangerschaftsabbruch noch invasive diagnostik (siehe kapitel 1.15 , gleiches gilt für die behandlung von warzen (eigene daten). diese erfahrungen beruhen allerdings auf geringen fallzahlen. empfehlung für die praxis: die lokale behandlung mit 5-fluorouracil ist, mit ausnahme einzelner warzen (verrucae vulgares), in der schwangerschaft kontraindiziert, salicylsäure sollte als alternativ-therapie geprüft werden. die behandlung von condylomata sollte bis nach der geburt verschoben werden oder andere vorgehensweisen wie kryotherapie und trichloressigsäure gewählt werden. die lokale anwendung dieses zytostatikums stellt jedoch keine indikation für einen risikobegründeten abbruch der schwangerschaft oder invasive diagnostik dar (siehe kapitel 1.15). g 2.17.14 lithium pharmakologie und toxikologie. lithium wird neben der oralen therapie von bipolaren störungen (siehe abschnitt 2.11.11) auch zur lokalen therapie einer seborrhoischen dermatitis eingesetzt (z. b. efadermin salbe ® ). es besitzt eine antientzündliche wirkung. die perkutane penetration ist sehr gering und plasmakonzentrationen sind wesentlich geringer als nach oraler aufnahme (sparsa 2004 aufgrund letal verlaufender intoxikationen in den usa ("gasping-syndrom" mit progressiver enzephalopathie und schwerer metabolischer azidose, knochenmarkdepression und multiplem organversagen) ist benzylbenzoat in der neonatologie in verruf geraten. allerdings wurde in den o.g. fällen benzylbenzoat als spüllösung bei zentralen kathetern verwendet. nach äußerlicher applikation ergaben sich bisher, abgesehen von reizwirkungen auf haut und schleimhaut, weder im tierversuch noch bei der anwendung beim menschen hinweise auf nennenswerte toxizität (fölster-holst 2000) . crotamiton wird zu weniger als 1 % der applizierten dosis perkutan resorbiert. eine kumulation der substanz war bisher nicht nachweisbar. im vergleich zu anderen antiskabiosa soll es etwas weniger wirksam sein (fölster-holst 2000) . bei kokosöl ist ein toxisches potenzial nicht anzunehmen (richter 2005) . lindan hat ein neurotoxisches potenzial. lindan 0,3 %ig wird zu 10 % perkutan resorbiert (fölster-holst 2000; siehe auch abschnitt 4.12.7). im tierversuch konnte gezeigt werden, dass sich lindan nicht nur im fettgewebe, sondern auch im hoden anreichern und zur zerstörung von leydig-zellen führen kann (suwalsky 2000) . nach europäischen umweltrichtlinien darf es nur noch bis ende 2007 verwendet werden. die synthetischen pyrethroide allethrin i, permethrin und pyrethrin haben längere halbwertszeiten als das "natürliche" pyrethrum, weshalb dieses bei der therapie einer pedikulose bevorzugt werden sollte. permethrin wird zu etwa 2 % perkutan resorbiert (fölster-holst 2000) . aufgrund seiner langzeitwirkung wird es als effektiver angesehen als pyrethrum, obwohl keine systematischen studien zum vergleich beider substanzen vorliegen. weltweit ist eine erhebliche zunahme von resistenzen gegen pyrethroidderivate, einschließlich permethrin festzustellen (richter 2005) . die prospektive untersuchung von 113 schwangeren mit anwendung von permethrin-shampoo, 31 im 1. trimenon, ergab keinen hinweis auf ein embryotoxisches risiko (kennedy 2005 , kennedy 2003 (sudakin 2003) . eine mutter, die in afrika während der gesamten schwangerschaft neben einer malariaprophylaxe mit chloroquin ihre arme und beine täglich mit einer 25 %igen deet-lotion eingerieben hatte, brachte ein in seiner geistigen entwicklung retardiertes kind zur welt (schaefer 1992) . da deet neurotoxische eigenschaften besitzt und über die haut resorbiert wird, schließen die autoren einen kausalen zusammenhang nicht völlig aus. es gibt allerdings keine weiteren berichte zu entwicklungstoxischen schäden beim menschen. in einer prospektiven randomisierten doppelblindstudie fanden sich bei 449 schwangeren, die im 2. und 3. trimenon durchschnittlich 1,7 g/tag deet anwendeten, im vergleich zur kontrollgruppe keine unterschiede in der entwicklung der neugeborenen. bei 8 % der behandelten frauen war deet im nabelschnurblut nachweisbar. unterschiede in der entwicklung der kinder bis zum 1. lebensjahr zeigten sich nicht (mcgready 2001) . zur anwendung von deet im 1. trimenon liegen keine systematischen untersuchungen vor, nur 3 einzelfallbeobachtungen mit gesund geborenen kindern (eigene daten). icaridin hat ein geringeres toxisches potenzial als deet, systematische untersuchungen zur schwangerschaft liegen allerdings nicht vor. empfehlung für die praxis: von der bedenkenlosen, großflächigen anwendung von insektenrepellents vom typ des deet über längere zeit ist in der schwangerschaft abzuraten. in gebieten mit hohem malariarisiko, die während einer schwangerschaft nur aus zwingenden gründen besucht werden sollten, ist das mit der anwendung von deet verbundene risiko für mutter und kind als eindeutig geringer einzuschätzen als das risiko durch eine malariainfektion. pyrethroidhaltige repellents sind zu meiden. wo immer möglich, sollten in der schwangerschaft andere repellents einschließlich icaridin bevorzugt werden. weder die anwendung von deet im 1. trimenon noch von pyrethroidhaltigen repellents erfordert einen risikobegründeten abbruch der schwangerschaft oder invasive diagnostik (siehe kapitel 1.15). g 2.17.17 augen-, nasen-und ohrentropfen augen-, nasen-und ohrentropfen dürfen bei entsprechender indikation generell auch in der schwangerschaft angewendet werden. allerdings gilt auch hier, dass eine wohl begründete medikamentenwahl erfolgen sollte und sowohl fragwürdige kombinationspräparate als auch (pseudo-)innovationen während der schwangerschaft zu meiden sind. im zweifelsfall kann man sich an empfehlungen zur systemischen therapie in den entsprechenden abschnitten orientieren. insbesondere bei augentropfen ist mit einer quantitativen arzneimittelresorption über die konjunktiven zu rechnen. daher ist nicht auszuschließen und teilweise beobachtet worden, dass beispielsweise atropinartige substanzen und betarezeptorenblocker (siehe abschnitt 2.8.2) als augentropfen die fetale herzfrequenz erhöhen bzw. senken können. bedrohliche situationen sind bei üblichen dosen zum diagnostischen weittropfen oder zur glaukombehandlung nicht zu erwarten. die ebenfalls zur glaukomtherapie verwendeten carboanhydrasehemmer brinzolamid (azopt ® ), dorzolamid (z. b. trusopt ® ) und zur systemischen anwendung acetazolamid (z. b. diamox ® ) sind zwar nicht systematisch untersucht, bisher haben sich jedoch bei den länger eingeführten präparaten keine negativen auswirkungen auf den fetus gezeigt. eigene daten zu insgesamt ca. 10 prospektiv dokumentierten schwangerschaften mit mütterlicher brinzolamid-oder dorzolamidtherapie deuten nicht auf ein embryotoxisches risiko hin. die mütterliche therapie mit 750 mg/tag acetazolamid (diamox ® ) in den letzten 3 tagen vor entbindung führte bei einem mit 34 wochen geborenen kind zu tachypnoe, respiratorisch-metabolischer azidose, hypoglykämie und hypokaliämie. die serumkonzentration 5 stunden nach der geburt betrug 2,9 ? g/ml, das entspricht beinahe der therapeutischen konzentration bei erwachsenen (3-10 ? g/ml). nach normalisierung des ph-wertes besserten sich die klinischen symptome spontan. am 11. tag war kein acetazolamid mehr nachweisbar, die weitere entwicklung des kindes verlief normal (ozawa 2001) . bei den neugeborenen von 12 frauen, die wegen eines idiopathischen, erhöhten intrakraniellen drucks mit durchschnittlich 500 mg/tag acetazolamid behandelt wurden, 9 davon im 1. trimenon, waren keine fehlbildungen oder andere auffälligkeiten nachweisbar (lee 2005) . zu latanoprost (z. b. xalatan ® ) wurde über 10 prospektiv dokumentierte behandlungen berichtet, 9 davon im 1. trimenon. eine schwangerschaft endete mit einem spontanabort. die 9 reifgeborenen kinder wiesen keine fehlbildungen auf minoxidil findet oral als antihypertensivum anwendung. es hat eine vasodilatatorische wirkung und wird lokal bei androgener alopezie und anderen arten von haarausfall angewendet (z. b. regaine ® frauen lösung). die substanz ist lipophil, ihre perkutane resorption soll 2-3 % betragen. dabei werden serumkonzentrationen erreicht, die weit unterhalb einer therapeutischen, antihypertensiv wirksamen konzentration für erwachsene liegen. in einer prospektiven studie wurden 17 schwangere mit minoxidil-lösung behandelt, eines von 15 lebend geborenen kindern wies eine herzfehlbildung auf (shapiro 2003) . zwei eigene prospektiv erfasste schwangerschaften mit exposition im 1. trimenon endeten mit der geburt gesunder kinder. bei einer frau, die seit einigen jahren mindestens zweimal täglich minoxidil lokal auf ihre kopfhaut applizierte, diagnostizierte man beim fetus hirn-, herz-und vaskuläre fehlbildungen. der pathologische befund zeigte eine deutliche herzvergrößerung mit einer distalen stenose der aorta, ein erheblich verlängertes colon sigmoideum, eine hirnventrikelerweiterung, zerebrale hämorrhagien sowie ischämische areale in der plazenta (smorlesi 2003) . in einer weiteren publikation wird nach einer mehrjährigen lokalen 2 %igen minoxidil-behandlung über eine ausgeprägte kaudale hypotrophie des fetus berichtet mit aplasie der unteren wirbelsäule, fehlanlage der unteren extremitäten und des harnableitenden systems, kompletter nierenagenesie und ösophagusatresie (rojansky 2002 (biesalski 2001) . der tagesbedarf beträgt etwa 1 mg retinol oder 2 mg g -carotin. vitamin a wird ähnlich wie vitamin c im embryo angereichert. die konzentration von vitamin-a-metaboliten im serum ist bei schwangeren im 1. trimenon vermindert und beträgt zwischen 0,26 und 7,7 ? g/l, in der zweiten schwangerschaftshälfte steigt sie auf etwa 150 % des wertes nichtschwangerer frauen an (malone 1975) . selbst nach 3-wöchiger gabe von täglich 30.000 ie vitamin a liegen die spitzenwerte der metaboliten retinsäure und isotretinoin höchstens geringfügig über den vorher gemessenen konzentrationen (wiegand 1998). eckloff und mitarbeiter (1991) wiesen bei einer tagesdosis von 50.000 ie vitamin a einen anstieg der plasmakonzentrationen von all-trans-retinoinsäure nach, die zu isotretinoin metabolisiert wird. toxikologie. in kapitel 2.17 "dermatika und lokaltherapeutika" wird ausführlich beschrieben, dass vitamin-a-derivate, wie die retinoide isotretinoin und acitretin, die zur therapie schwerer formen von akne und psoriasis eingesetzt werden, beim menschen teratogen wirken und daher in der schwangerschaft absolut kontraindiziert sind. vor etwa 20 jahren wurde erstmals diskutiert, dass vitamin-a-präparate in dosen über 25.000 ie pro tag ähnlich wie die retinoide beim menschen teratogen wirken und das charakteristische "retinoidsyndrom" auslösen können (rosa 1986 ). in deutschland haben 1988 aufgrund einer empfehlung des bundesgesundheitsamtes die hersteller von multivitaminpräparaten die zusammensetzung ihrer produkte so geändert, dass sie nicht mehr als 6.000 ie pro tagesdosis enthalten. in anderen ländern wurde ähnlich verfahren (bundesgesundheitsamt 1988 , laschinski 1988 , teratology society 1987 . die unbedenklichkeit solch niedriger dosen wurde verschiedentlich, u. a. durch die studie von an schwangeren in ungarn, bestätigt. eine untersuchung des european network of teratology information services (entis) ergibt erstaunlicherweise keine hinweise auf eine teratogene wirksamkeit selbst hoher, im 1. trimenon genommener vitamin-a-dosen (10.000-300.000, mittelwert 50.000 ie/tag). insbesondere können die in einer anderen studie gemachten beobachtungen nicht bestätigt werden, dass hohe dosen, insbesondere solche über 40.000 ie/tag, einen bestimmten typ von zns-anomalien verursachen (rothman 1995) . die entis-studie ist mit 423 schwangeren die bisher größte vitamin a (retinol) 445 vitamin-a-studie (mastroiacovo 1999 (botto 2001) . man muss dazu kritisch anmerken, dass die zahl der mütter mit einer hohen dosis in beiden gruppen sehr gering war. daher kann dieses ergebnis allenfalls als hypothese gewertet werden, die durch andere studien bisher nicht bestätigt wurde. eine weitere fall-kontroll-studie fand keinen zusammenhang zwischen einer im normbereich liegenden vitamin-a-aufnahme aus leber oder multivitaminprodukten und dem auftreten von spaltbildungen (mitchell 2003) . generell wird in der schwangerschaft vor dem verzehr von leber gewarnt, da eine portion (100 g), auch gebraten, bis zu 400.000 ie retinol enthalten kann. es gibt jedoch kaum klinische hinweise darauf, dass der verzehr von leber zu fehlbildungen beim menschen führt. das könnte daran liegen, dass vitamin a bzw. der teratogene metabolit all-trans-retinolsäure nach leberverzehr nur 1/20 jener konzentrationsspitzen im serum erreicht, die nach einnahme standardisierter vitamin-a-dosen in tablettenform gemessen wurden (buss 1994 obwohl der zusammenhang zwischen folsäuremangel und neuralrohrdefekt nicht genau geklärt ist, bestätigen die meisten epidemiologischen untersuchungen bis heute einen protektiven effekt der folsäuresubstitution (wald 2001 . auswirkungen auf den methioninstoffwechsel spielen neben dem eventuell ebenfalls relevanten methioningehalt der mütterlichen ernährung offenbar eine rolle . ein protektiver effekt wird auch bei anderen fehlbildungen diskutiert (bailey 2005 , koletzko 2004 , wie z. b. kardialen defekten , botto 2003 oder analatresie (myers 2001 ) sowie bei aborten (gindler 2001 . man ist sich heute weitgehend einig, dass alle frauen in der frühschwangerschaft, möglichst schon ab planung einer schwangerschaft, bis zur woche 8 täglich 400 ? g folsäure zusätzlich einnehmen sollen. frauen mit risikoanamnese (bereits neuralrohrdefekte in der familie aufgetreten) oder bei folatantagonistischer therapie, z. b. mit bestimmten antiepileptika, werden 4-5 mg/tag empfohlen. eine überdosierung der folsäure schädigt nach bisherigen erfahrungen die embryonale entwicklung nicht. die maskierung einer seltenen vitamin-b 12 -mangelanämie durch eine folsäureeinnahme ist zwar möglich, hat aber angesichts der zeitlich begrenzten einnahme keine bedeutung. in manchen ländern, wie z. b. kanada und den usa, wird eine allgemeine anreicherung von nahrungsmitteln (getreideprodukten) mit folsäure vorgeschrieben und zwar mit etwa 1,5 mg/kg. in den usa wurde seit der folsäureanreicherung über eine abnahme der neuralrohrdefekte um 19 % ) und 26 % (mills 2004) , in kanada um 47 % (persad 2001) berichtet. auch in der bundesrepublik deutschland und anderen europäischen ländern wird die folsäureanreicherung von nahrungsmitteln erörtert, da die substitution mit tabletten nur von wenigen schwangeren praktiziert wird und die durchschnittliche ernährung in deutschland nur 200 ? g/tag statt der erforderlichen 400 ? g enthält (bgvv 2000) . in deutschland befolgen nur 20 % der frauen, die eine schwangerschaft planen, und bei nicht geplanten schwangerschaften nur 9 % den rat einer perikonzeptionellen folsäureeinnahme. in den niederlanden sind es hingegen über 50 % (gärtner 1999) . häufig beobachtet man infolge unzureichender ärztlicher beratung, dass folsäure erst im späten 1. trimenon und danach eingenommen wird. die hochempfindliche phase der neuralrohrentwicklung ist aber schon mit 6 wochen abgeschlossen. gelegentlich wird diskutiert, ob eine ausgewogene ernährung für die folsäureversorgung ausreicht. epidemiologische daten und untersuchungen zum intraerythrozytären folsäurestatus unter berücksichtigung verschiedener zufuhrbedingungen sprechen dagegen. einerseits gibt es hinweise darauf, dass mütter von kindern mit neuralrohrdefekten einen pathologisch erhöhten bedarf an folsäure aufweisen, der deutlich über der mit "gesunder" ernährung zugeführten menge liegt. andererseits ergab sich aus einer vergleichenden untersuchung, dass nur tabletten und angereicherte nahrungsmittel, nicht aber diätetisch aufgenommene folsäure zu einer signifikanten verbesserung des folsäurestatus führen (cuskelly 1996) . schließlich soll nicht unerwähnt bleiben, dass nach kritischer auswertung aller vorliegenden daten auch heute noch zweifel an der protektiven wirkung einer zusätzlichen verabreichung von folsäure in der schwangerschaft geäußert werden (källén 2002 , kalter 2000 . empfehlung für die praxis: um die protektive wirkung der folsäure bei neuralrohrdefekten zu nutzen, sollten möglichst schon bei der planung einer schwangerschaft sowie während der ersten 8 wochen 0,4 mg/tag eingenommen werden. die substitutionsdosis ist auf 4-5 mg/ tag g 2.18.10 vitamin c (ascorbinsäure) pharmakologie und toxikologie. vitamin c (z. b. cebion ® , ctebe ® ) ist im zellulären stoffwechsel zur aufrechterhaltung des oxidations-reduktions-gleichgewichts wichtig. der tagesbedarf an vitamin c beträgt etwa 100 mg. vitamin-c-mangel führt zu skorbut mit störungen des kollagenstoffwechsels und zur blutungsneigung. die vitamin-c-konzentration im fetalen blut ist 3-mal so hoch wie im mütterlichen blut, da sich nach dem plazentaren übergang von dehydro-ascorbinsäure vitamin c im fetus anreichert (malone 1975) . es ist nicht bekannt, ob gaben von vitamin c das reduktions-oxidations-gleichgewicht des fetus beeinflussen. diskutiert werden der zusammenhang zwischen mütterlichem vitamin-c-mangel und einem erhöhten risiko für gestationsdiabetes (zhang a und 2004 sowie eine assoziation zwischen mütterlichem vitamin-c-spiegel bzw. einer protektiven vitamin-c-substitution im 2. und 3. trimenon und vorzeitigem blasensprung (casanueva 2005 , tejero 2003 pharmakologie. eisen(ii)-salze (z. b. eisendragees-ratiopharm ® ) werden nach oraler gabe gut resorbiert und sind für die eisensubstitution in der schwangerschaft geeignet. der zusatz von vitaminen und spurenelementen zu oralen eisen(ii)-präparaten hat keinen erwiesenen therapeutischen nutzen. kombinationspräparate mit folsäure sind nicht zu empfehlen, da die eisenresorption aus diesen zubereitungen um bis zu 60 % reduziert ist (pietrzik 1988) . etwa 15-20 % der patientinnen, die eisen-(ii-)präparate einnehmen, klagen über gastrointestinale beschwerden, die bei vorbestehender morgendlicher übelkeit zum wechsel auf ein anderes präparat oder zur beendigung der eisensubstitution zwingen können (letzky 1983) . die parenterale applikation von eisenpräparaten (singh 2000) wie eisen(iii)-gluconat-komplex (ferrlecit ® ) ist nur bei ausgeprägter anämie indiziert und macht in kombination mit anderen antianämika eine transfusionstherapie in der schwangerschaft weitgehend überflüssig. toxikologie. der verdacht, dass nach eisensubstitution in der schwangerschaft die fehlbildungsrate gering ansteigen könnte (nelson 1971) , hat sich in umfangreichen prospektiven untersuchungen nicht bestätigt (dfg 1977 , royal college 1975 ein fallbericht beschreibt die mütterliche calciumtherapie wegen osteoporose mit einer tagesdosis von 1.000 mg bis woche 6 und die weitere therapie mit täglich 3.000 mg, kombiniert mit einer colecalciferolbehandlung bis zum ende der (drillings-)schwangerschaft. in woche 21 kam es zum spontanabort eines fetus, die beiden anderen kinder wurden gesund geboren (harsch 2001 in einer neueren prospektiven studie wurden die schwangerschaften von 15 frauen mit biphosphonat-therapie, davon 9 mit exposition im 1. trimenon ausgewertet (alendronsäure: 7, etidronsäure: 5, pamidronsäure: 1, risedronsäure: 2). die schwangerschaften endeten mit 14 lebendgeborenen und einem spontanabort. hinweise auf embryotoxische effekte fanden sich nicht (levy 2004 . in einer kleinen retrospektiven untersuchung wurde ein protektiver effekt für eine neurodermitis des kindes bei frauen mit atopieneigung festgestellt (dunstan 2003) . empfehlung für die praxis: eine überzeugende notwendigkeit zur substitution mit omega-3-fettsäuren besteht bei ausgewogener ernährung nicht. alternative heilmittel und phytotherapeutika die verträglichkeit alternativer heilmittel in der schwangerschaft ist bisher nicht systematisch untersucht. es liegen auch keine fallberichte über teratogene schädigungen bei einhalten der empfohlenen dosierungen vor, sie sind zumindest bei homöopathika auch nicht zu erwarten. gegen akupunktur ist ebenfalls nichts einzuwenden, wenn sie fachkundig in der schwangerschaft praktiziert wird. nicht alle pflanzlichen präparate sind harmlos: bei phytotherapeutika sollten therapeutische dosen eingehalten und tees nicht exzessiv genossen werden. die herkunft sollte deklariert sein, da kontaminationen mit unerwünschten pflanzlichen bestandteilen, schwermetallen, wie z. b. blei (tait 2002) (gut 2004) . allerdings sind auch hier systematische untersuchungen zur teratogenität und embryotoxizität rar. trotz der breiten anwendung von pflanzlichen therapeutika auch in der schwangerschaft sind hinweise oder fallberichte zu teratogenen effekten selten und zumindest bei einhaltung der empfohlenen dosierungen auch kaum zu erwarten. eine retrospektive studie zur anwendung von phytotherapeutika konnte beim vergleich mit "schulmedizinischen therapeutika" kein erhöhtes fehlbildungsrisiko durch pflanzliche substanzen nachweisen (leung 2002) . eigene daten umfassen 244 prospektiv dokumentierte schwangerschaften, davon 142 mit anwendung im 1. trimenon. ein teratogenes risiko oder hinweise auf vermehrte spontanaborte lassen sich nicht beobachten. bei der anwendung pflanzlicher zubereitungen und teedrogen sollte stets darauf geachtet werden, dass ihre herkunft bekannt und die inhaltsstoffe eindeutig deklariert sind. vor einer kontamination mit pflanzenschutzmitteln oder toxischen schwermetallen sowie mikrobieller verunreinigung nicht zertifizierter ware wird gewarnt (ihrig 2005) . auf alkoholische zubereitungen sollte zumindest bei längerfristiger therapie verzichtet werden. ein fallbericht beschreibt exzessiven gebrauch von phytopharmaka mit 19 % alkoholgehalt in der frühschwangerschaft, angeblich ohne weitere alkoholeinnahme. das kind wies typische zeichen eines fetalen alkoholsyndroms auf (ernst 2002) . diese kasuistik sollte eher als anekdotisch betrachtet werden, vergleichbare berichte gibt es bisher nicht. g 2.19.3 aloe vera pharmakologie und toxikologie. aloe vera wird extern eingesetzt zur förderung der wundheilung oder bei hautproblemen und intern als immunstimulans. systematische untersuchungen zur oralen anwendung in der schwangerschaft fehlen bisher. aloe soll eine stimulierende wirkung auf die uterusmuskulatur haben, so dass theoretisch das risiko für einen spontanabort erhöht sein könnte (ernst 2002) . die lokale anwendung in der schwangerschaft ist wahrscheinlich unproblematisch (nordeng 2004 in einer großen retrospektiven studie wurden 1.049 frauen zu ihrem lakritzkonsum (starke "skandinavische lakritze") in der schwangerschaft, dem geburtsgewicht der kinder sowie dem schwangerschaftsalter bei entbindung befragt. bei starkem wöchentlichen lakritzkonsum ab 500 mg glyzyrrhizin war zwar keine signifikante reduzierung des geburtsgewichtes nachweisbar, es fand sich jedoch ein leicht erhöhtes risiko für eine geburt bereits vor 38 wochen (strandberg 2001) . in einer retrospektiven finnischen studie wurden 95 frauen mit frühgeborenen kindern mit 107 frauen mit reifgeborenen hinsichtlich ihres lakritzkonsums ("skandinavische lakritze") verglichen. es wurde festgestellt, dass bei starkem lakritzkonsum ab wöchentlich 500 mg glyzyrrhizin ein 2-3fach erhöhtes frühgeburtsrisiko besteht. es wird vermutet, dass glyzyrrhizin einen lokalen anstieg des prostaglandinspiegels im uterus bewirken und dadurch vorzeitige wehen auslösen könne (strandberg 2002) . die methodik der studie wurde jedoch wegen fehlender adjustierung auf weitere faktoren des lebensstils kritisiert (hughes 2003 (ernst 2002) . bei gabe von himbeerblättertee zur erleichterung und verkürzung der geburt bei 192 frauen waren keine nebenwirkungen nachweisbar. eine verkürzung der geburt konnte in der ersten phase nicht, in der zweiten phase um 10 min registriert werden. weiterhin fanden sich signifikant weniger forceps-entbindungen als in der kontrollgruppe (ernst 2002 (portnoi 2003) . in 4 anderen randomisierten plazebokontrollierten doppelblindstudien zeigte sich jedoch, dass sowohl die übelkeit als auch die häufigkeit des erbrechens mit ingwer signifikant reduziert wurden (willetts 2003 , keating 2002 , vutyavanich 2001 , fischer-rassmusen 1990 . bis auf eine arbeit ohne hinweise zur entwicklung des neugeborenen (keating 2002) , fanden sich in den anderen 3 studien keine hinweise auf ein erhöhtes abort-oder fehlbildungsrisiko. eine neuere randomisiert-kontrollierte studie ermittelte keine unterschiede in der wirksamkeit und bei der entwicklung der neugeborenen gegenüber vitamin b 6 (pyridoxin). ein erhöhtes fehlbildungsrisiko war nicht erkennbar (smith 2004) . auch andere substanzspezifische nebenwirkungen wurden bisher nicht beobachtet (betz 2005) . da ingwer in vitro eine hemmung der thromboxansynthese bewirkt, nahmen einige autoren an, dass er die testosteron-rezeptor-bindungen beim fetus beeinflussen und somit auf die geschlechtsdifferenzierung im kindlichen hirn einwirken könnte (backon 1991) . dieser effekt erscheint jedoch im üblichen dosisbereich unwahrscheinlich. im tierversuch wurden in 2 studien keine entsprechenden effekte beobachtet (weidner 2001 , wilkinson 2000 . empfehlung für die praxis: die anwendung von ingwer bei schwangerschaftsübelkeit und -erbrechen in üblicher dosierung stellt kein problem dar. g 2.19.14 johanniskraut (hypericum perforatum) pharmakologie und toxikologie. johanniskraut (z. b. esbericum ® ) wird bei leichten depressiven verstimmungen, psychovegetativen störungen und nervöser unruhe mit erfolg eingesetzt (nordeng 2004) . durch eine induktion von isoenzymen von cytochrom p 450 (cyp 450) können interaktionen mit anderen arzneimitteln auftreten, z. b. eine beeinträchtigung der wirkung oraler kontrazeptiva (siehe abschnitt 2.11). weiterhin wurden unter der johanniskraut-therapie zyklusstörungen (zwischenblutungen, menstruationsunregelmäßigkeiten) beobachtet (yue 2000) . im tierversuch fanden sich keine hinweise für teratogene effekte (jurgens 2003 (leuschner 1997) . beim menschen gibt es bisher keine hinweise darauf, dass therapeutische dosen teratogen sind, allerdings wurde dies nicht systematisch untersucht. theroretisch kann kampfer spontanaborte auslösen. es ist plazentagängig und der fetus bildet noch keine enzyme zur hydroxylierung und glucuronidierung von kampfer (rabl 1997 publiziert wurden 2 fälle, in denen eine längere einnahme von pyrrolizidinalkaloidhaltigen zubereitungen in der schwangerschaft zu einer leberschädigung mit venöser verschlusskrankheit (veno occlusive disease) und zum tod des kindes führte. im ersten fall trank die mutter während der gesamten schwangerschaft einen pflanzentee, bei dem später festgestellt wurde, dass er pyrrolizidinalkaloide enthielt (ernst 2003) . zunächst war der huflattich im tee angeschuldigt worden, schließlich stellte sich heraus, dass die ursache bei einer verunreinigung mit pestwurz lag. im zweiten fall hatte die schwangere zum täglichen kochen eine türkische gewürzmischung verwendet, die diverse pyrrolizidinalkaloide enthielt (rasenack 2003) . eine südafrikanische veröffentlichung soll über 20 kinder mit veno occlusive disease nach mütterlicher einnahme pyrrolizidinalkaloidhaltiger phytotherapeutika und hoher mortalitätsrate beobachtet haben. bei überlebenden kindern entwickelte sich eine leberzirrhose mit portaler hypertension (ernst 2003) . 20 msv, jedoch meist unter 50 msv, wenn sich der uterus im strahlengang befand. dies schließt zwei untersuchungsgänge unter einbeziehung des unterbauchs einschließlich übersichtsaufnahme (scout) ein. zur dosisberechnung gehören u. a. die röhrenspannung in kv, die anzahl der rotationen, die oberste und unterste schicht mit angabe des korrespondierenden wirbelkörpers oder in cm oberhalb des rumpfendes, die mas (milliamperesekunden) pro rotation oder als summenangabe für die gesamte untersuchung, die schichtdicke, der vorschub und der gerätetypische so genannte kerma-wert, der die dosis auf der rotationsachse in freier luft angibt und mit ctdi luft bezeichnet wird. die streustrahlung bei untersuchung anderer körperregionen wie oberbauch, thorax, extremitäten oder zahnröntgen ist zu vernachlässigen, weil sie weit unter 1 msv liegt. auswirkungen von röntgenstrahlung. röntgenstrahlen können in abhängigkeit von der dosis und vom entwicklungsstadium des embryos fruchttod, fehlbildungen verschiedener organsysteme, vor allem der augen, allgemeine wachstumsretardierung, mikrozephalie und mentale retardierung hervorrufen. dies ist sowohl tierexperimentell als auch empirisch beim menschen belegt . in den ersten 5 tagen nach konzeption (also noch während der "alles-oder-nichts-phase") wird die niedrigste letaldosis mit 10 rad (100 mgy) angegeben. während der eigentlichen embryogenese wird dieser wert mit 25-50 rad, später mit über 100 rad (1 gy) beziffert . schwere zns-fehlbildungen während der frühen embryogenese (18-36 tage nach konzeption) sollen erst ab 20 rad (200 mgy) zu erwarten sein. mit bleibender wachstumsretardierung rechnet man bei 25-50 rad. mikrozephalie und mentale retardierung wurden besonders nach dosen oberhalb 20 rad zwischen woche 10 und 17 beobachtet. die meisten untersuchungen kommen zu dem schluss, dass unterhalb einer strahlendosis von 50 mgy, entsprechend 5 rad, mit keinem nennenswerten anstieg des fehlbildungsrisikos beim menschen zu rechnen ist a, sternberg 1973 . eine kürzlich veröffentlichte studie beobachtet ein geringeres geburtsgewicht im zusammenhang mit zahnröntgen in der schwangerschaft und interpretiert dies als folge einer funktionsstörung der schilddrüse, die beim zahnröntgen ebenfalls getroffen werde (hujoel 2004) . andere autoren widersprechen dieser hypothese und halten eher die zugrunde liegende zahnerkrankung für ursächlich (lockhart 2004). weitaus schwieriger als die beurteilung des teratogenen strahlenrisikos ist die frage nach mutagenen und krebsauslösenden effekten zu beantworten. für mutagene effekte gibt es keine schwellendosis, unterhalb derer wie bei der teratogenese kein effekt zu erwarten ist. punktmutationen ereignen sich bekanntermaßen auch spontan. die zur verdopplung der punktmutationsrate führende strahlendosis wird mit 100-200 rad (1-2 gy) angegeben a, neel 1999 ). einerseits bedeutet eine verdopplung der mutationsrate eines bestimmten gens noch keine häufigkeitsverdopplung einer daran gekoppelten erkrankung. andererseits sollten die völlig unzureichenden kenntnisse zu den auswirkungen auf spätere generationen zu großer zurückhaltung bei der definition unbedenklicher expositionsgrenzwerte für die gesamtbevölkerung führen . bei den eltern von etwa 500 an neuroblastom erkrankten kindern wurden röntgenanwendungen vor der schwangerschaft nicht häufiger durchgeführt als bei einer gesunden kontrollgruppe (patton 2004) . in einer studie an zwillingsschwangerschaften ermittelten harvey und mitarbeiter (1985) bei einer fetaldosis von 0,01 sv einen anstieg des leukämierisikos um den faktor 2,4. lengfelder (1990) zieht bereits ein erhöhtes leukämierisiko in erwägung, wenn die zusätzliche pränatale strahlenexposition des embryos im bereich der natürlichen hintergrundbelastung von etwa 0,001 sv liegt. dagegen nehmen andere autoren bei exposition mit 0,02-0,05 sv noch kein risiko für den embryo an (boice 1999) . wakeford und mitarbeiter (2003) haben für kinder unter 15 jahren das relative und absolute risiko errechnet, nach intrauteriner strahlenexposition an einem karzinom zu erkranken. das absolute risiko geben sie mit 8 % pro gray an. ihre detaillierte berechnung basiert auf der weltweit größten datensammlung zum karzinomrisiko durch intrauterine röntgenexposition, vorwiegend pelvimetrie, dem oxford survey of childhood cancers (oscc). die autoren leiten vergleichbare risiko-koeffizienten aus den japanischen daten von atombombenopfern ab und fassen zusammen, dass selbst für eine vergleichsweise niedrige fetaldosis von 10 msv, die in den 50er jahren bei einer röntgenaufnahme des beckens erreicht wurde, bereits ein erhöhtes risiko vorliegt. andere autoren halten solche risikoannahmen für zu hoch. sie berufen sich ebenfalls auf die nicht einmal 1.000 überlebende umfassende gruppe intrauterin exponierter hiroshimaopfer und auf verlaufsdaten von exponierten kindern in hiroshima. diese nicht selten als beleg für ein vergleichsweise niedriges krebsrisiko nach radioaktiver exposition zitierten untersuchungen sind jedoch angesichts methodischer mängel und der damaligen politischen interessenlage der amerikanischen untersucher kritisch zu bewerten. empfehlung für die praxis: bei anwendung bildgebender diagnostischer verfahren im bereich des unterbauches sollte bei frauen im gebärfähigen alter primär auf röntgenverfahren verzichtet werden, insbesondere wenn eine schwangerschaft nicht sicher auszuschließen ist. die mit "nein" beantwortete frage nach einer vorliegenden schwangerschaft schließt eine solche bekanntermaßen nicht aus! jede röntgenuntersuchung des unterbauchs, von deren ergebnis nicht unmittelbar vital indizierte therapiemaßnahmen abhängen, sollte sicher-heitshalber nur in der ersten zyklushälfte durchgeführt werden. falls röntgenuntersuchungen unverzichtbar sind, darf nur mit den modernsten geräten und unter optimalem schutz der fruchthöhle gearbeitet werden. röntgenaufnahmen außerhalb der genitalregion und der fruchthöhle stellen weder eine indikation für einen risikobegründeten abbruch der schwangerschaft noch für weitere vorsorgemaßnahmen dar (siehe kapitel 1.15 (bal 2005 , chow 2004 , read 2004 , schlumberger 1996 . von zahlreichen kindern dieser studien liegen berichte zu ihrer entwicklung bis ins erwachsenenalter vor, ohne dass hinweise auf spätfolgen wie karzinomentstehung oder genetische defekte daraus erkennbar werden. schlumberger und mitarbeiter (1996) beobachten jedoch eine erhöhte abortrate, wenn die behandlung innerhalb eines jahres vor der schwangerschaft stattfand. die autoren diskutieren sowohl die exposition der gonaden als auch eine ungenügende schilddrüsenhormoneinstellung nach der nuklear-medizinischen therapie als ursachen. read und mitarbeiter (2004) (newnham 1993 , visser 1993 , ließen sich diese auswirkungen nicht bestätigen. nachfolgeuntersuchungen an etwa 1.500 kindern im alter von 1-8 jahren, deren mütter 5-mal per ultraschall zwischen woche 18 und 38 untersucht worden waren, ergaben hinsichtlich gewichtszunahme und anderer entwicklungsparameter keine auffälligkeiten im vergleich zu einer kontrollgruppe mit nur einer ultraschalluntersuchung (newnham 2004) . gepulste doppleruntersuchungen, flowmessungen und untersuchungen im 1. trimenon erfordern eine höhere energiedosis und können bei längerer fokussierung eines bereichs theoretisch eher zur überwärmung embryonalen gewebes und zu entwicklungsschäden führen. daher wird weiterhin empfohlen, ultraschall nur medizinisch indiziert anzuwenden (bly 2005) . empfehlung für die praxis: ultraschalluntersuchungen im medizinisch notwendigen umfang sind in der schwangerschaft akzeptabel. video-und einzelbilddarstellungen fürs familienalbum gehören nicht dazu. bei der mrt werden magnetfelder erzeugt, die sich nicht von anderen elektrischen anwendungen einschließlich radiowellen unterscheiden. die magnetfeldstärke wird für die patienten mit 1,5 bis 2 tesla (t) und für das untersuchungspersonal mit 5-100 mt angegeben. die mrt wird seit rund 20 jahren auch in der schwangerschaft angewendet. mittels mrt wurde z. b. die plazenta lokalisiert, fetale diagnostik betrieben und geprüft, ob die beckenmaße eine vaginale entbindung zulassen (de wilde 2005). die überwiegend im 2. und 3. trimenon gemachten erfahrungen haben bislang keine negativen auswirkungen der dabei erzeugten elektromagnetischen felder und des gerätelärms auf den fetus erbracht (kok 2004 b, übersicht in robert 1999 , brent 1993 . dies betrifft auch nachuntersuchungen von kindern im alter von 3 bzw. 8-9 jahren einschließlich hör-und sehtests (kok 2004 , baker 1994 . untersuchungen an mrt-personal ergaben keinen anhalt für ein reproduktionstoxisches risiko (gauthier 2000 , übersicht in cragan 1999 . vor allem indigokarmin, aber auch evans-blau sind in zahlreichen fällen mit guter verträglichkeit zur markierung bei amniozentese verwendet worden. indigokarmin ist dem serotonin ähnlich, daher ist eine indirekt vasoaktive wirkung nicht auszuschließen. dennoch sind keine dem methylenblau vergleichbaren effekte bei über 150 dokumentierten schwangerschaften beobachtet worden (cragan 1993 (halperin 1990 ). tierexperimente zeigten ebenfalls keine teratogenen effekte. die substanz wurde nach applikation am auge in der amnionflüssigkeit einer schwangeren nachgewiesen. auch zur retina-angiographie und zur messung des hepatischen blutflusses mit indocyaningrün (mit natriumiodid in icg-pulsion ® ) liegen keine hinweise auf unverträglichkeit für das ungeborene vor. indocyaningrün konnte nicht im nabelvenenblut nachgewiesen werden (fineman 2001 ethanol hemmt die ausschüttung der hormone oxytozin und vasopressin aus dem hypophysenhinterlappen. bei gesteigerter wehentätigkeit führt ethanol in hoher dosis ( g 2‰) sowohl nach intravenöser als auch nach oraler gabe bei zwei drittel der schwangeren zur wehenhemmung. die pränatale schädigung durch chronischen alkoholkonsum beruht auf der direkten teratogenen wirkung von ethanol und seines abbauproduktes acetaldehyd auf den fetus. das fas und seine varianten treten nur bei chronischer mütterlicher alkoholkrankheit auf, wobei eine korrelation zwischen fas-risiko und fortschreiten der mütterlichen alkohol-krankheit besteht (majewski 1978) . der eigentliche schädigungsmechanismus ist auch heute trotz intensiver klinischer und tierexperimenteller forschung noch nicht bekannt. die in einigen tierversuchen beobachteten entwicklungstoxischen auswirkungen paternaler alkoholexposition ließen sich beim menschen bisher nicht belegen (passar 1998 (day 2002 , olson 1997 . das so genannte "binge-drinking" oder das "saturday-night drinking", also das gelegentliche heftige trinken ist in der schwangerschaft sicher gefährlicher für das kind als das regelmäßige soziale trinken geringer mengen. so wiesen bailey und mitarbeiter (2004) nach, dass bei alkohol trinkenden schwangeren nicht nur die absolute menge, sondern auch das trinkmuster für die schädigung des ungeborenen kindes ausschlaggebend ist. in einer kontrollierten prospektiven studie fand dosiskorrelierte verhaltensstörungen noch im vorschulalter bei sonst kognitiv nicht beeinträchtigten kindern, deren mütter während der schwangerschaft "binge-drinking" praktizierten. spectrum disorder (fasd) werden heute vor allem in den usa alle formen der kindlichen schädigung durch den chronischen alkoholabusus während der schwangerschaft zusammengefasst: das klassische fetale alkoholsyndrom (fas) als schwerste ausprägung, die fetalen alkohol-effekte (fae) ohne die typische kraniofaziale dysmorphie, die durch alkohol bedingten funktionellen entwicklungsneurologischen störungen (alcohol related neurodevelopmental disorders, zeitpunkt noch an diese diagnose zu denken ist (streissguth 1996 , spohr 1993 . bis ins erwachsenenalter reichen die folgen der intrauterinen alkoholschädigung mit körperlichem minderwuchs, mentalen entwicklungproblemen und anpassungsstörungen besonders in der arbeitswelt (autti-ramo 2005 diese xanthinderivate werden als lipophile substanzen gut aus dem magen-darm-trakt resorbiert, sie passieren die plazenta und können bei stärkerem coffeinkonsum eine vermehrte aktivität des fetus mit zunahme der atembewegungen und veränderungen seiner herzfrequenz einschließlich arrhythmien hervorrufen. nach bisheriger erfahrung sind jedoch keine negativen folgen für das neugeborene und die weitere entwicklung im kindesalter zu erwarten (castellanos 2002) . im tierversuch führt coffein in extrem hohen dosen (200 mg/kg/tag) zu geringfügigen entwicklungsstörungen an den phalangen. in den usa wurde daher 1980 mit unterstützung der gesundheitsbehörden, der verbraucherverbände und der kaffee-und cola-produzenten untersucht, ob coffeinhaltige getränke auch bei menschen fehlbildungen hervorrufen können. im gegensatz zu den genannten tierversuchen nehmen erwachsene durchschnittlich nicht mehr als 2-5 mg/kg/tag an coffein zu sich. ausführliche epidemiologische studien in verschiedenen ländern erbrachten keine hinweise auf embryotoxische effekte unter diesen bedingungen (christian 2001) . eine neue prospektive dänische untersuchung fand eine leicht erhöhte totgeburtenrate, wenn die schwangere mehr als 8 tassen kaffee getrunken hatte (wisborg 2003) . zahlreiche publikationen befassen sich mit einer möglicherweise erhöhten abortrate und intrauteriner wachstumsretardierung bei coffeingenuss (signorello 2004 , leviton 2002 . eine metaanalyse unter einbeziehung von rund 50.000 schwangeren ergab hinweise auf eine leicht erhöhte rate an spontanaborten und wachstumsretardierten kindern (iugr), wenn die mutter mehr als 150 mg coffein pro tag zu sich nahm (fernandes 1998) . bis heute sind derartige auswirkungen bei durchschnittlichem konsum nicht eindeutig allein dem kaffee zuzuschreiben und von anderen einflüssen wie z. b. rauchen und alkohol zu trennen. in einer untersuchung wurde nur bei männlichen neugeborenen eine reduktion des geburtsgewichts beobachtet (vik 2003) . der insgesamt schwache zusammenhang zwischen kaffeekonsum und fehlgeburten wurde auch damit begründet, dass schwangerschaftsübelkeit ohnehin mit einem geringeren fehlgeburtsrisko assoziiert ist und gleichzeitig das kaffeetrinken verleidet. barr und mitarbeiter (1991) konnten bei den kindern von 500 schwangeren keinen effekt auf somatische entwicklungsparameter und iq bis zum alter von 7,5 jahren finden. eine beeinträchtigung der weiblichen fertilität durch regelmäßigen genuss größerer mengen von coffein wurde ebenfalls diskutiert. . statistisch signifikant waren die jeweiligen konzentrationsunterschiede zwischen kindern von aktiven und passiven raucherinnen sowie von frauen aus nichtraucherhaushalten. fehlbildungen. rauchen ist embryo-und fetotoxisch, birgt aber offenbar kein erhebliches fehlbildungsrisiko. allerdings wird von zahlreichen autoren ein zusammenhang zwischen rauchen während der frühschwangerschaft und lippen-und gaumenspalten diskutiert a & b, zeiger 2004 , chung 2000 , romitti 1999 ), insbesondere bei gleichzeitigem vorliegen eines transforming-growth-factor§ (tgf§ )-polymorphismus als beispiel für das zusammenspiel von genetischen und umweltfaktoren bei der teratogenese. in einer metaanalyse von 24 internationalen publikationen ließ sich nachweisen, dass mütterliches rauchen in der schwangerschaft mit einem erhöhten risiko für nichtsyndromale orofaziale spalten verbunden ist, wobei der effekt konstanter und deutlicher bei lippenspalten mit und ohne gaumenbeteiligung war als bei isolierten gaumenspalten (deacon 2005) . das risiko für kinder von raucherinnen mit genetischer disposition (siehe oben) wird mit maximal 1:183 angegeben gegenüber einer prävalenz in der gesamtbevölkerung von etwa 1:500 (chung 2000) . in anderen untersuchungen werden leicht erhöhte risiken für kraniosynostose , källén 1999 ), gastroschisis (martinez-frias 1997), harnwegsanomalien (li 1996) , herzfehlbildungen (wasserman 1996) , extremitätendefekten (källén 1997 , wasserman 1996 und klumpfuß (skelly 2002) erörtert, die bislang aber nicht als eindeutig erwiesen gelten. (chanoine 1991) . 7 morbidität und mortalität in der kindheit sind im zusammenhang mit rauchen schwierig zu beurteilen, weil fast immer sowohl eine pränatale als auch eine postnatale exposition besteht. soweit bekannt, scheint rauchen in der schwangerschaft keine langfristigen auswirkungen auf das postnatale wachstum zu haben. eine untersuchung an neugeborenen, die noch nicht direkt rauch exponiert waren, hat gezeigt, dass kinder von raucherinnen häufiger einschränkungen respiratorischer funktionen aufwiesen. ein kombinierter effekt von prä-und postnataler exposition auf die entstehung von nahrungsmittelallergien in den ersten 3 lebensjahren wurde von einer untersuchergruppe beobachtet (kulig 1999) . eine weitere publikation betont den prädiktiven wert der konzentration des metaboliten cotinin im mekonium für das risiko frühkindlicher atemwegsinfektionen (nuesslein 1999) . 7 in einer prospektiven "follow-up"-studie konnte noch im alter von 8 jahren ein erhöhtes risiko für übergewicht nachgewiesen werden (chen 2005) . eine vermehrte infektneigung, besonders von otitiden unter den kleinkindern rauchender mütter ist inzwischen allgemein akzeptiert. auch koliken kommen häufiger vor (shenassa 2004) . im vergleich zu nicht rauchenden müttern führt tabakkonsum während der schwangerschaft zu einem 2fach höherem risiko, dass die kinder an sids (sudden infants death syndrome) sterben , alm 1998 . in einer englischen fallserie mit 136 prospektiv erfassten ecstasy exponierten schwangeren wurden 12 kinder mit entwicklungsanomalien bei insgesamt 78 lebendgeborenen beschrieben. es handelt sich dabei jedoch z. t. um kleine anomalien (z. b. fußdeformitäten), ein typisches muster war nicht zu erkennen. knapp die hälfte der mütter hatte zusätzlich alkohol oder andere drogen in nicht näher bezeichneter menge zu sich genommen (mcelhatton 1999) . in einer weiteren untersuchung an 228 schwangeren wurde eine doppelt so hohe rate kleiner entwicklungsanomalien im vergleich zu einer nicht exponierten kontrollgruppe beobachtet. hier zeigten sich in der neugeborenenzeit gehäuft neurologische auffälligkeiten einschließlich störungen des muskeltonus und übererregbarkeit. die spontanabortrate war nicht erhöht, aber es ereigneten sich drei totgeburten in der exponierten gruppe (felix 2000) . auch in dieser untersuchung wurden neben rauchen und alkohol z. t. noch andere drogen genommen. niedrigeres geburtsgewicht und entzugserscheinungen wurden auch von weiteren untersuchern beschrieben (smith 2003) . unter 65 bis zum 14. lebensjahr nachuntersuchten kindern wurden signifikant häufiger lernschwierigkeiten in der schule beobachtet. allerdings betrieb ein großteil der mütter während der schwangerschaft nicht nur amphetaminabusus, sondern konsumierte zusätzlich opiate und alkohol, rauchte mehr als 10 zigaretten täglich und befand sich in einer problematischen psychosozialen lage. nur 22 % der kinder lebten mit 14 jahren noch bei ihren müttern (cernerud 1996) . empfehlung für die praxis: schwangere sollen amphetamine unter allen umständen meiden. eine dennoch erfolgte exposition rechtfertigt keinen risikobegründeten schwangerschaftsabbruch (siehe kapitel 1.15). nach ausgeprägtem konsum im 1. trimenon sollte die normale entwicklung des fetus per ultraschallfeindiagnostik bestätigt werden. g 2.21.6 cannabis pharmakologie und toxikologie. marihuana, die blätter der cannabispflanze (indischer hanf) mit dem harzartigen extrakt haschisch gehört außer alkohol, nikotin und ecstasy zu den häufig in der schwangerschaft konsumierten drogen. beim rauchen sollen im vergleich zu tabak eine 5fach höhere kohlenmonoxidkonzentration und ein 3fach höherer teergehalt im blut erreicht werden. delta-9-tetrahydrocannabinol (thc), der wichtigste von mehreren 100 wirkstoffen des marihuanas, passiert die plazenta und kann zur abnahme der kindlichen herzfrequenz führen. die fehlbildungsrate ist nach genuss von marihuana in der schwangerschaft nicht höher; aber ein regelmäßiger konsum erhöht möglicherweise die perinatale sterblichkeit. eine metaanalyse ergab keine schlüssigen hinweise auf eine erniedrigung des geburtsgewichts, zumindest bei moderatem, nur gelegentlichem cannabisgenuss (english 1997) . wie bei anderen drogen sind embryotoxische effekte hier häufig nicht von zusätzlichen einwirkungen wie z. b. zigarettenrauchen zu unterscheiden. es gibt bisher auch keine hinweise, dass die in früheren tierexperimentellen untersuchungen marihuana zugeordneten chromosomenbrüche klinische relevanz besitzen. neugeborene können entzugserscheinungen mit zittrigkeit und unruhe zeigen. die daten zur weiteren entwicklung im kindesalter sind uneinheitlich. eine langzeitstudie fand bei kindern, deren mütter während der schwangerschaft regelmäßig, d. h. mehrfach pro woche bis täglich marihuana konsumiert hatten, im alter von 4 jahren eine signifikant beeinträchtigte sprach-und gedächtnisleistung (fried 1990 ) sowie einen signifikant kleineren kopfumfang auch bei älteren kindern, obwohl die geburtsmaße nicht auffällig waren (fried 1999) . insgesamt werden die abweichungen der kognitiven entwicklung dieser kohorte als subtil beschrieben a) und keine auswirkungen auf das spätere wachstum und die pubertätsentwicklung gesehen (fried 2001 b) . eine andere langzeitstudie hat die entwicklung von 606 kindern, deren mütter während der schwangerschaft alkohol oder cannabis konsumiert hatten, im alter von 10 jahren anhand verschiedener tests und der beurteilung durch die lehrer bewertet. hatte die mutter im 1. oder 2. trimenon täglich marihuana geraucht, fanden sich häufiger einschränkungen bei den kognitiven leistungen (goldschmidt 2004) . auch diese autoren bezeichnen die ergebnisse insgesamt als subtil und bewerten die übertragbarkeit auf andere cannabis exponierte schwangere zurückhaltend. empfehlung für die praxis: schwangere sollen marihuana unter allen umständen meiden. dennoch erfolgter konsum rechtfertigt keinen risikobegründeten schwangerschaftsabbruch (siehe kapitel 1.15). sporadischer genuss begründet auch keine zusätzliche diagnostik. g 2.21.7 kokain pharmakologie. kokain (koks, schnee) ist das alkaloid benzoylekgoninmethylester des coca-strauches (erythroxylon coca), der hauptsächlich in den anden wächst. die blätter enthalten etwa 1 % kokain. in europa ist die stimulierende droge seit mitte des 19. jahrhunderts bekannt. 1884 wurde kokain als anästhetikum eingeführt. es ist den lokalanästhetika chemisch verwandt und hat sich nur zur äußerlichen anwendung in der augen-und hno-heilkunde durchgesetzt. crack ist die freie base (free base) des kokains und kann geraucht werden. kokain blockiert die wiederaufnahme von noradrenalin und dopamin an der synapse und erhöht auf diese weise die katecholaminkonzentration. dies führt zu einem sympathikomimetischen und zentral stimulierenden effekt. bei oraler aufnahme wird kokain wegen seiner vasokonstriktorischen wirkung und der hydrolytischen spaltung im magen nur langsam resorbiert. in der leber wird es innerhalb von 2 stunden zum unwirksamen hauptmetaboliten benzoylekgonin metabolisiert. etwa 20 % werden unverändert über die niere ausgeschieden. die resorption erfolgt intranasal innerhalb von 20 minuten (verzögerung durch vasokonstriktion). intravenöse applikation oder rauchen von crack führen innerhalb weniger minuten zum wirkungseintritt. kokain findet sich in relativ hoher konzentration in der amnionflüssigkeit und die konzentration fällt aufgrund der geringen clearance nur langsam ab. daher kann der fetus auch über seine bis zur schwangerschaftswoche 24 gut durchlässige haut aus der amnionflüssigkeit kokain aufnehmen (woods 1998) . toxikologie. in den usa wurde bei 4 bis 20 % aller schwangeren ein kokainkonsum ermittelt (fantel 1990) . bis anfang der 80er jahre hielt man kokain für eine pränatal nicht toxische droge. dann wurden zahlreiche entwicklungsstörungen dem wiederholten kokain-oder "crackgenuss" in der schwangerschaft angelastet. sporadischer gebrauch in der frühschwangerschaft bei intakten lebensverhältnissen und ohne weitere schädigende faktoren wie alkohol, andere drogen, infektionen, mangelernährung und traumata scheint nach den bisher vorliegenden erfahrungen das fehlbildungsrisiko nicht nennenswert zu erhöhen. erwiesene folgen des ausgeprägten abusus sind eine erhöhte abortrate, frühgeburten, totgeburten, intrauterine wachstumsverzögerung und mikrozephalie. außerdem wurde über zerebrale infarkte, nekrotisierende enterokolitis beim neugeborenen, fehlbildungen von urogenital-und skelettsystem sowie über intestinale atresien und infarkte berichtet a, hoyme 1990 , schaefer 1990 , mercado 1989 , chasnoff 1988 ). das weite spektrum der morphologischen veränderungen kann durch eine vasokonstriktion mit minderdurchblutung der plazenta und in fetalen organen erklärt werden. während der gesamten schwangerschaft kann es infolgedessen zu (fokalen) differenzierungsund wachstumsstörungen kommen. trotz der vielzahl publizierter einzelschädigungen exponierter kinder von kokain abhängigen müttern ließ sich bis heute kein typisches kokain-syndrom definieren, wie z. b. das "coke-baby" mit charakteristischen persistierenden morphologischen und psychomentalen folgen (little 1996) . kokain und "crack" rufen bei schwangeren stärkere herz-kreislaufund neurologische wirkungen hervor als bei nichtschwangeren. es wird diskutiert, ob die schädigung des embryos nach minderperfusion eine direkte folge des sauerstoffmangels ist oder eher durch hochreaktive, toxische sauerstoffradikale nach reperfusion des ischämischen gewebes verursacht wird, denn im 1. trimenon verfügt die fetoplazentare einheit noch nicht über genügend schützende antioxidantien. postnale entwicklung. die akuten symptome beim neugeborenen sind weniger ausgeprägt als nach einem heroinentzug: schlafstörungen, tremor, trinkschwäche, erbrechen, schrilles schreien, niesen, tachypnoe, weiche stühle und fieber. darüber hinaus wurden in verschiedenen studien auffälligkeiten in neurologischen tests bei neugeborenen sowie spätere verhaltensabweichungen, entwicklungsstörungen, eeg-veränderungen und vereinzelt plötzlicher säuglingstod beobachtet (eyler 1998 b) . die auffälligkeiten in der neonatalzeit sind in der regel nach einem jahr nicht mehr nachweisbar. zwar finden sich in sorgfältigen prospektiven studien diskrete physiologische und entwicklungsneurologische effekte, ihr ausmaß auf die kindliche entwicklung ist jedoch nicht ausreichend zu bewerten (schiller 2005) . bandstra und mitarbeiter (2002 fanden in einer prospektiven longitudinalstudie an 200 kindern bis zum 7. lebensjahr, dass auch schwere kokain-exposition während der schwangerschaft nicht eindeutig als unabhängiger risikofaktor für die mentale und psychomotorische entwicklung sowie für die entwicklung des verhaltens der kinder nachzuweisen war. zu einem ähnlichen ergebnis kommen beeghly und mitarbeiter (2006) in einer untersuchung zur sprachentwicklung im alter von 6 und 9,5 jahren. eine literaturanalyse der von 1994-2000 publizierten arbeiten ermittelt in 37 prospektiven studien zu kindern bis zum 6. lebensjahr keinen überzeugenden beweis dafür, dass pränatale kokainexposition mit einer entwicklungsschädigenden störung assoziiert ist. viele der symptome, die für kokainspezifisch gehalten wurden, waren eher mit anderen pränatalen faktoren korreliert, wie tabak, marihuana, alkohol und der qualität der kindlichen lebensbedingungen (frank 2001) . richardson (1996 ) und messinger (2004 stellten fest, dass frauen, die während der schwangerschaft kokain einnahmen, eher an stress und ernährungsstörungen litten, öfter alleinstehend waren und dazu neigten, zusätzlich marihuana, tabak, alkohol und tabletten zu konsumieren. zusammengefasst muss man davon ausgehen, dass kokainkonsum eine hochrisikoschwangerschaft bedingt. die beim kind beobachteten mentalen und motorischen defizite sind nicht nur direkte folge dieser "chemischen" exposition sondern assoziiert mit den anderen o.g. risikofaktoren und dem häufig resultierenden niedrigen geburtsgewicht. empfehlung für die praxis: da kokain potenziell entwicklungstoxisch ist, darf es während der gesamten schwangerschaft nicht konsumiert werden. kokainkonsum rechtfertigt keinen risikobegründeten schwangerschaftsabbruch (siehe kapitel 1.15). bei wiederholter anwendung, vor allem unter problematischen lebensbedingungen, sollte durch eine ultraschallfeindiagnostik die normale entwicklung des fetus überprüft werden. g 2.21.8 lsd pharmakologie und toxikologie. in älteren arbeiten wurde der verdacht geäußert, das halluzinogen lsd (lysergsäurediethylamid) könne fehlbildungen an augen, gehirn und skelett verursachen (übersicht in . auch über chromosomenbrüche wurde berichtet. die im wesentlichen in einzelfallberichten beschriebenen klinischen auffälligkeiten können nicht als erwiesen angesehen werden. allerdings sind die vorliegenden daten für eine differenzierte risikobewertung unzureichend. empfehlung für die praxis: schwangere sollen lsd unter allen umständen meiden. ein dennoch erfolgter konsum rechtfertigt keinen risikobegründeten schwangerschaftsabbruch (siehe kapitel 1.15 bei den neugeborenen können die schweren, meist 24-72 stunden nach geburt auftretenden entzugssymptome mit atemnotsyndrom, hyperirritabilität, tremor, diarrhö, erbrechen, störungen des schlaf-wach-rhythmus und z. t. therapierefraktäre zerebrale krampfanfälle ohne behandlung zum tod führen. bei 10 % der kinder treten symptome bis hin zu zerebralen krampfanfällen erst verzögert nach 1 bis 5 wochen auf. das risiko für lebensbedrohliche entzugssymptome ist besonders hoch, wenn die abhängigkeit der mutter nicht bekannt ist und ein zuverlässiges monitoring sowie die rechtzeitige medikamentöse prophylaxe mit opiaten (morphin) nicht eingeleitet werden. nach erfolgreicher therapie der entzugssymptome sind bleibende defekte offenbar nicht zu erwarten. jedoch scheint der plötzliche kindstod (sids) bei pränatal opiat exponierten kindern häufiger aufzutreten als in kontrollgruppen nicht exponierter kinder. ein akuter opiatentzug während der schwangerschaft kann fruchttod und vorzeitige wehen auslösen. gute erfolge wurden mit der umstellung der schwangeren auf die ersatzdrogen methadon bzw. levomethadon (l-polamidon ® ) (halbwertszeit 15-60 stunden) erzielt. neonatale atemdepression und entzugssymptome treten auch unter methadon und anderen ersatzdrogen auf. es gibt hinweise dafür, dass die entzugssymptomatik nach methadon sogar schwerer und länger verläuft als nach intrauteriner heroin-exposition. am wirksamsten und verträglichsten wird der säugling mit einer oralen opiatzufuhr therapiert (arlettaz 2005 , siddappa 2003 . obwohl es plausibel erscheint, dass die entzugserscheinungen mit der mütterlichen dosis am ende der schwangerschaft korrelieren, konnten berghella und mitarbeiter (2003) keine signifikanten unterschiede zwischen methadon substituierten schwangeren mit täglich 40, 60 oder 80 mg erkennen. zu den in den letzten jahren vermehrt diskutierten alternativen ersatzdrogen gehört buprenorphin (halbwertszeit 2-4 stunden). nach den erfahrungen an über 300 schwangeren scheint die entzugssymptomatik im vergleich zum methadon milder zu verlaufen (übersicht bei , kayemba-kay's 2003 , schindler 2003 . als ursache dafür wird ein geringerer plazentarer transfer diskutiert (nanovskaya 2002 , rohrmeister 2001 . andere therapiekonzepte bei heroin-abhängigen schwangeren betreffen naltrexon-implantate (hulse 2004) . anders als bei alkoholgeschädigten kindern ist die neurologische und kognitive entwicklung offenbar stärker durch das soziale umfeld in den ersten lebensjahren beeinflusst als durch den umfang der pränatalen opiat-exposition. intakte familienverhältnisse z. b. durch adoption nach der geburt erlauben offenbar eine weitgehend normale intellektuelle entwicklung der kinder (ornoy 2001 , coles 1993 . nur aufmerksamkeitsdefizit und hyperaktivität (adhd) traten auch bei adoptierten kindern noch häufiger auf als bei unbelasteten kontrollkindern, allerdings mit 37 % deutlich seltener als bei den im drogenumfeld verbliebenen kindern (67 %). dies ergab eine nachuntersuchung von 5-bis 10-jährigen kindern (ornoy 2001) . empfehlung für die praxis: akuter opiatentzug ist während der schwangerschaft zu vermeiden. bei heroinabhängigkeit ist eine einstellung auf methadon oder buprenorphin zu empfehlen. die substitution erfordert eine genaue dosistitrierung und sollte nur von erfahrenen ärzten vorgenommen werden. die tägliche methadon-oder buprenorphindosis muss sich am vorangegangenen drogenkonsum und an der stärke der entzugssymptome orientieren. zusätzlicher drogenkonsum kann durch screening im urin nachgewiesen werden. durch umfangreiche soziale hilfestellung muss versucht werden, die beschaffungskriminalität zu beenden. in aussichtslosen fällen ist rechtzeitig auf eine adoption bzw. auf eine pflegefamilie hinzuarbeiten (siehe oben). neugeborene müssen ggf. über mehrere wochen beobachtet werden, damit auch verzögert auftretende schwere entzugserscheinungen mit opiaten behandelt werden können. in einzelnen fällen wurden im zusammenhang mit phencyclidinabusus mikrozephalie, gesichtsasymmetrie und ein komplexes intraund extrakraniales fehlbildungssyndrom beschrieben, ohne dass sich bisher eine kausale beziehung belegen ließ. intrauterine wachstumsretardierung und postnatale interaktionsdefizite sowie andere neurologische abweichungen wurden ebenso beobachtet wie opiattypische entzugserscheinungen. nachuntersuchungen an 62 kindern im alter von einem jahr erbrachten keine auffälligkeiten gegenüber einer kontrollgruppe (wachsmann 1989). tierexperimentell wurde eine degeneration fetaler kortexneurone beschrieben (übersicht in . empfehlung für die praxis: schwangere sollen phencyclidin unter allen umständen meiden. ein dennoch erfolgter gebrauch rechtfertigt keinen risikobegründeten schwangerschaftsabbruch (siehe kapitel 1.15). eine ultraschallfeindiagnostik sollte die normale entwicklung des fetus bestätigen. g 2.21.12 psilocybin pharmakologie und toxikologie. psilocybin ist ein halluzinogen aus pilzen ("magic mushrooms"). es gibt keine ausreichenden erfahrungen in der schwangerschaft, die eine differenzierte risikobewertung erlauben. auf der anderen seite wurden bisher keine reproduzierbaren anomalien im zusammenhang mit psilocybin-einnahme beschrieben. lungsparameter war der mit 6,5 % erhöhte anteil geistig retardierter kinder der einzig signifikante befund, der aber aufgrund der kleinen fallzahl nicht verallgemeinert werden sollte. in einer späteren, deutlich erweiterten untersuchung desselben autors findet sich ebenfalls keine signifikant erhöhte fehlbildungsrate. das gilt auch für die 27 schwangeren, die zwischen woche 5 und 10 hohe medikamentendosen in suizidaler absicht eingenommen hatten . in einer dänischen publikation zu 122 schwangeren fand man zwar eine verdoppelte rate an spontanaborten aber kein erhöhtes fehlbildungsrisiko und keine zunahme der frühgeburten (flint 2002). häufig wird die frage gestellt, wie eine schwangere nach suizidversuch behandelt werden sollte. dabei spielen sowohl die sorge um eine spezifische embryotoxizität der eingenommenen noxe eine rolle als auch die unbedenklichkeit der indizierten antidotbehandlung. bisherige erfahrungen belegen, dass eine gefährdung des fetus primär von der noxe und nicht von der antidot-behandlung ausgeht. dies wurde z. b. bei methanol-intoxikation ebenso beobachtet wie bei überdosen von paracetamol und eisenpräparaten. andererseits gibt es praktisch zu keinem antidot epidemiologische studien im 1. trimenon, die die verträglichkeit der therapie für den embryo belegen. die vorliegenden fallberichte und fallserien geben bislang jedoch keinerlei hinweise auf teratogenität oder fetotoxizität, abgesehen vom chelatbildner penicillamin, der ethanoltherapie und methylenblau (nach injektion in die amnionhöhle). zum chelatbildner dimercaprol (2,3-dimercaptopropanol, synonym: british anti-lewisite = bal) liegen mehrere fallberichte zur anwendung bei arsen-und bleivergiftung vor, die keine hinweise für ein embryotoxisches risiko geben (bailey 2003) . der chemisch verwandte, in der bundesrepublik deutschland zugelassene chelatbildner 2,3-dimercapto-1-propansulfonsäure (dmps; dimaval ® ) ist analog zu bewerten. allerdings ist bei jeder länger dauernden chelattherapie zu bedenken, dass auch essentielle nahrungsbestandteile, wie z. b. zink eliminiert werden und sich daraus potenziell riskante mangelzustände für den fetus ergeben können. umfangreichere erfahrungen gibt es zu antidotsubstanzen, die vor allem bei anderen indikationen eingesetzt werden (z. b. atropin, pyridoxin) . bei der auch in der schwangerschaft häufiger beschriebenen paracetamolvergiftung in suizidaler absicht besteht das risiko der mütterlichen und fetalen leberschädigung. die therapie mit dem antidot acetylcystein (fluimucil antidot ® ) richtet sich wie bei nichtschwangeren nach der eingenommenen menge paracetamol oder der paracetamol-konzentration im serum der mutter (mcelhatton 1996) . acetylcystein überwindet die plazenta und ist auch beim fetus als antidot wirksam (horowitz 1997) . auch bei eisenvergiftungen in suizidaler absicht würde das unterlassen einer antidottherapie mit deferoxamin (desferal ® ) mutter und fetus gefährden (mcelhatton1991, olenmark 1987 . empfehlung für die praxis: grundsätzlich muss jede schwangere mit einer intoxikation so behandelt werden wie eine nichtschwangere, d. h. alle therapeutischen maßnahmen, die aus klinisch toxikologischer sicht indiziert sind, sollten anwendung finden. allerdings sollte die entgiftungsbehandlung aktuellen richtlinien folgen. die in den folgenden kasuistiken beschriebenen therapiemaßnahmen sind nicht immer aktuell, da es sich z. t. um "historische" berichte handelt. aufgrund neuer erkenntnisse haben sich die therapieempfehlungen bei vergiftungen in den vergangenen jahren teilweise grundlegend geändert. da es den rahmen dieses buches sprengen würde, darauf einzugehen, sollten im bedarfsfall kompetente giftinformationszentren gefragt oder fachbücher (z. b. mühlendahl 2003) konsultiert werden. mehrere fallberichte beschreiben arsenvergiftungen bei schwangeren nach dem 1. trimenon. in den meisten fällen waren die neugeborenen gesund, sogar bei intoxikationsbedingten enzephalopathien der mutter. es wurden jedoch auch letale verläufe berichtet und frühgeburten mit kurz darauf verstorbenem neugeborenen (bollinger 1992 , daya 1989 , lugo 1969 , kantor 1948 . co überwindet die plazenta und kann im fetalen blut zu vergleichbaren konzentrationen wie im mütterlichen führen. empirische beobachtungen, tierexperimentelle ergebnisse und theoretische berechnungsmodelle zeigen, dass im fetus mit einer mehrstündigen verzögerung sowohl beim anfluten als auch beim abbau des co zu rechnen ist. erst nach etwa 14-24 stunden wird ein gleichgewicht erreicht, die eliminationshalbwertszeit ist beim fetus 4-bis 5-mal länger als bei der mutter (übersicht in barlow und sullivan 1982) . zns-schäden beim fetus werden insbesondere dann beschrieben, wenn die mutter bewusstseinseingeschränkt war bzw. eine grad-4oder -5-symptomatik aufwies, auch dann, wenn sie sich rasch wieder erholte. zu den möglichen späteren klinischen auffälligkeiten beim kind zählen mentale und motorische entwicklungsretardierungen, aber auch schwere zerebralparetische schädigungen. der reife fetus reagiert empfindlicher auf die co-intoxikation als der embryo während der organogenese. eine geringgradige akute exposition der mutter mit vorübergehenden, leichten symptomen wie kopfschmerzen und übelkeit (entsprechend grad 1-2) oder die chronische co-exposition, z. b. im rahmen der beim rauchen üblichen belastungen (1 packung zigaretten/tag oder bis etwa 30 ppm raum-bzw. stadtluft aufgrund gewerblicheroder umwelt-exposition), resultiert in mütterlichen cohb-konzentrationen von 2-10 % und ist offenbar nicht mit fetalen schäden assoziiert , übersicht in barlow 1982 . der fetus einer raucherin toleriert eine zusätzliche co-exposition keineswegs besser, weil er bereits daran gewöhnt ist, denn seine kompensationsfähigkeit ist möglicherweise schon ausgeschöpft. seit über 70 jahren (maresch 1929 ) gibt es berichte über co-vergiftungen in der schwangerschaft, die sowohl unauffällige verläufe, als auch fruchttod und zns-defekte beschreiben (aubard 2000 , kopelman 1998 . abgesehen von den zns-schäden sind teratogene, also fehlbildungsauslösende wirkungen des co unwahrscheinlich. bedenken zur fetalen verträglichkeit der therapie der co-vergiftung mit der hyperbaren oxygenierung wegen möglicher retinaschädigung oder vorzeitigem verschluss des ductus arteriosus wurden geäußert, aber nicht bestätigt (silverman 1997) . auf jeden fall ist eine unterbehandelte schwere co-intoxikation das größere fetotoxische risiko. empfehlung für die praxis: aufgrund der stark verzögerten kinetik des co im fetalen organismus und dem daraus resultierenden erhöhten risiko hypoxischer zns-schädigung beim kind muss die indikation zur hyperbaren oxygenierung bei schwangeren mit co-bedingten bewusstseinseinschränkungen großzügig gestellt werden. die therapie sollte länger durchgeführt werden, als es symptome und co-konzentrationsverlauf bei der mutter nahe legen. jede schwangere mit bewusstseinseinschränkung durch co, mit einer über 20 % liegenden cohb-konzentration oder mit abweichungen der fetalen herzfrequenz (dezelerationen, tachykardie, silente herzfrequenz) muss so rasch wie möglich hyperbar behandelt werden und bis zum beginn der therapie 100 % sauerstoff erhalten. da co den fetus stark verzögert erreicht und nur sehr langsam wieder abgebaut wird, ist auch ein um viele stunden verzögerter behandlungsbeginn bei bereits einsetzender spontanbesserung mütterlicher symptome noch sinnvoll und indiziert! eine methanol-vergiftung in der schwangerschaft kann den fetus bei länger bestehender azidose sekundär schädigen. obwohl methanol plazentagängig ist, scheint der fetus zunächst durch seine langsamere verstoffwechselung des methanols zu dessen toxischen metaboliten wie formaldehyd relativ geschützt zu sein. die klassische therapie mit ethanol i.v. exponiert natürlich auch den fetus mit alkohol und ist aufgrund der nicht auszuschließenden neurologischen folgen, die vom "binge-drinking" und von der tokolyse mit alkohol bekannt sind, nicht als völlig unbedenklich zu bewerten. daher wird neuerdings auch fomepizol als alternatives antidot vorgeschlagen (velez 2003) . auf jeden fall darf weder bei methanol noch bei ethylenglykol eine (alkohol-)therapie aus falscher rücksicht auf den embryo unterbleiben (tenenbein 1997) . ein fallbericht mit methanol-intoxikation in der spätschwangerschaft beschreibt ein gesundes neugeborenes nach behandlung der mutter mit ethanol, hämodialyse und alkalisierung (hantson 1997) . in einem weiteren fall verstarben die mutter und das per sectio in woche 30 entbundene kind einige tage nach der geburt. bei der azidotischen mutter (ph 7,17) wurde nach 36 stunden eine alkohol-therapie begonnen und erst am 3. tag mit fomepizol behandelt. im blut des azidotischen neugeborenen (ph 6,9) fanden sich mit 61,6 mg/dl methanol ähnliche konzentrationen wie bei der mutter (belson 2004 ). einige fallberichte schildern akzidentelle und suizidale überdosierungen mit unterschiedlichem ausgang. eine mutter in schwangerschaftswoche 19 berichtete, zwei stunden nach aufnahme von chlorpyrifos in suizidaler absicht keine kindsbewegungen mehr gespürt zu haben. nach anfänglicher magenspülung wurde erst 10 stunden später eine intensivtherapie begonnen. inzwischen war der fetus verstorben. außer niedrigen mütterlichen pseudocholinesterase-spiegeln fanden sich hohe konzentrationen an chlorpyrifos im fetalen blut. einige weitere fälle einer organophosphat-intoxikation bei schwangeren endeten mit der geburt gesunder kinder. in diesen fällen erfolgte eine rasche therapie, u. a. mit atropin und pralidoxim (kamha 2005 ). eines dieser kinder entwickelte sich bis zum alter von 4 jahren unauffällig. in berichten über 9 schwangere, die in suizidaler absicht größere mengen des herbizids paraquat eingenommen hatten, wurde geschildert, dass kein fetus und nur zwei mütter die intoxikation überlebten. die paraquat-konzentrationen waren im fetus höher als im mütterlichen serum (talbot 1987) . ein weiterer fallbericht beschreibt die einnahme von 80-100 ml paraquat in suizidaler absicht in schwangerschaftswoche 6. die mutter wurde erfolgreich u. a. mit hämodialyse behandelt. die schwangerschaft schien sich unbeeinträchtigt weiter zu entwickeln, wurde aber in woche 9 abgebrochen. im embryonalen gewebe fanden sich 0,25 ? g/g und in der amnionflüssigkeit 0,05 ? g/ml paraquat. die mütterlichen serumwerte sollen zu diesem zeitpunkt deutlich darunter gelegen haben (initial waren es 4,8 ? g/ml). die autoren diskutieren einen größeren schutz des embryos gegenüber paraquat im vergleich zum reifen fetus. sie weisen darauf hin, dass insbesondere bei intoxikationen in der späteren schwangerschaft der dann ohnehin stärker gefährdete fetus ein für die mutter riskantes reservoir für rückflutendes paraquat darstelle und unter diesem aspekt ein schwangerschaftsabbruch erörtert werden müsse (tsatsakis 1996) . eine ausnahme ist der bericht über die geburt eines reifen, gesunden und sich bis zum alter von 5 jahren normal entwickelten mädchens, dessen mutter in schwangerschaftswoche 27 eine überdosis paraquat zu sich nahm und anschließend mit kohle-hämoperfusion, hochdosis-cyclophosphamid und methylprednisolon behandelt wurde (jenq 2005) . über rund 20 fälle von thalliumingestion in suizidaler absicht oder zur provokation eines aborts wird berichtet, sowie kürzlich über einen fall mit chronischer intoxikation durch ein thalliumhaltiges rodentizid am arbeitsplatz. die meisten kinder überlebten die mütterliche vergiftung bei adäquater therapie der mutter. außer alopezie scheinen frühgeburt und intrauterine wachstumsretardierung, nicht aber fehlbildungen mögliche folgen einer pränatalen exposition -auch im 1. trimenon -zu sein (hoffmann 2000) . vereinzelt gibt es berichte zur wasserintoxikation unter der geburt, z. b. den fall eines 6 stunden alten neugeborenen, das durch krämpfe und eine hyponatriämie mit 121 mmol/l auffiel (mutter: 126 mmol/l). in diesem fall hatte die mutter wenige stunden vor der geburt 3 liter wasser getrunken. die weitere entwicklung des kindes war unauffällig (mcelhatton 2001) . die in manchen fällen bei der mutter gemessenen ass-spiegel lagen über denen, die im tierversuch bereits teratogene schäden induzieren. entwickelte die mutter keine schweren toxischen symptome, so traten weder fetale blutungen noch spontanaborte oder intrauteriner fruchttod auf. diese befunde stehen im gegensatz zu der in anderen studien beobachteten zunahme der spontanabortrate nach therapeutischer anwendung von nichtsteroidalen antiphlogistika (nsaid) wie ass, ibuprofen etc. , nielsen 2001 . palatnick (1998) eine neonatale bromid-intoxikation mit hypotonie und späterer normaler entwicklung nach einnahme einer hohen dosis durch die mutter am ende der schwangerschaft belegt die anreicherung dieser substanz im fetus (pleasure 1975 ). eine carbamazepin-intoxikation in schwangerschaftswoche 33 in suizidaler absicht führte zum koma der patientin und wurde mit kohle und plasmapherese behandelt. hinweise auf eine beeinträchtigung des fetus zeigten sich nach der geburt nicht, apgar und nabelarterien-ph waren normal (saygan-karamursel 2005) . in schwangerschaftswoche 34 nahm eine frau 8 mg/kg colchicin ein. das kind wurde 10 stunden später per sectio geboren, war gesund und wies nur einen sehr niedrigen colchicinspiegel im serum auf ( x 5 ng/ ml). trotz intensivmedizinischer maßnahmen verstarb die mutter (blache 1982). fallsammlungen zu diazepam-intoxikationen haben bisher kein spezifisches entwicklungstoxisches risiko erkennen lassen (cerqueira 1988) . ein fallbericht beschreibt eine schwangere in woche 33, die ca. 100 mg eines benzodiazepins, wahrscheinlich diazepam eingenommen hatte. in ihrem serum fanden sich 175 ? g/l des benzodiazepins, im urin 303 ? g/l. in der kinetokardiotokographie etwa 8 stunden nach ingestion sah man erwartungsgemäß phasen silenter bis eingeschränkt undulatorischer oszillation der fetalen herzfrequenz. darüber hinaus fanden sich unmittelbar nach klinikaufnahme dezelerationen, die nicht mit uteruskontraktionen einhergingen, sondern mit phasen gesteigerter kindsbewegungen. die basalfrequenz war dabei nicht besonders auffällig. nach etwa 6 stunden hatte sich dies, als normalisierung gedeutet, wieder umgekehrt, d. h. es folgten akzelerationen auf die kindsbewegungen. dieses von der lage der schwangeren unabhängige phänomen wurde als passagere hypoxämie infolge der intoxikation gedeutet (heinrich 1996) . ein fallbericht beschreibt eine digitalis-intoxikation mit 8,9 mg digitoxin im 7. schwangerschaftsmonat. nach spontangeburt in woche 30 verstarb das kind am 3. lebenstag. beidseits fanden sich hämorrhagische infarkte der nieren und degenerative neuronale veränderungen im zns, die als hypoxische folge der anhaltenden bradykardie gewertet wurden (sherman 1960 ). es gibt mehrere publikationen zur eisen-überdosierung in der schwangerschaft (tran 2000 , mcelhatton 1998 , la-coste 1992 , dugdale 1967 . in einer fallserie wurden 85 schwangere mit überdosis nachverfolgt. sechs waren im 1. trimenon exponiert, 37 im 2. und 41 im 3. insgesamt gab es 73 neugeborene ohne fehlbildungen, 5 davon waren frühgeborene, eines hatte einen angeborenen genitalherpes und ein anderes -nach mütterlicher eisen-intoxikation in schwangerschaftswoche 36/37 -einen ausgeprägten neugeborenenikterus. fünf kinder wiesen unterschiedliche fehlbildungen auf, alle waren im 2. oder 3. trimenon exponiert. zwei spontanaborte in woche 22 und 29 wurden beobachtet, einer nach unmittelbar vorangehender vergiftung, ein anderer nach einem abdominaltrauma. fünf schwangerschaften wurden abgebrochen. serumeisenspiegel wurden in 51 fällen ermittelt, davon lagen 21 im mittleren toxischen bereich (60-89 ? mol/l) und 8 im hochtoxischen ( g 90 ? mol/l) (mcelhatton 1998) . eine chelattherapie mit intravenös verabreichtem deferoxamin ist indiziert, wenn der serumeisenspiegel über 55 ? mol/l liegt, oder wenn eine überdosis anzunehmen ist und die schwangere krampft, bewusstlos oder im schock ist. in diesen fällen ist keine serumeisenbestimmung abzuwarten. in der o.g. fallserie erhielten 41 frauen deferoxamin und 20 eine andere entgiftungsbehandlung (ipecac 10, magenspülung 6, aktivkohle 3, bikarbonat 1). alle mütter überlebten. es wurden keine toxischen effekte durch deferoxamin beobachtet. ähnliche ergebnisse wurden von anderen autoren beschrieben (khoury 1995 , turk 1993 . empfehlung für die praxis: ein erhebliches risiko ist für den fetus nicht gegeben, wenn die mutter wie eine nichtschwangere nach einer eisenintoxikation adäquat behandelt wird. allerdings sind aufgrund der geringen fallzahlen zum 1. trimenon keine abschließenden aussagen zur teratogenität zu machen. ein schwangerschaftsabbruch aus furcht vor einer schädigung der frucht ist nicht gerechtfertigt. nach einer überdosis von 300 mg haloperidol in schwangerschaftswoche 34 wurden für einige tage verminderte kindsbewegungen im ultraschall beobachtet. das in woche 39 geborene kind entwickelte sich bis zum 18. lebensmonat normal (hansen 1997 beim erwachsenen wird paracetamol zu einem aktiven metaboliten verstoffwechselt, der in hohen konzentrationen hepatotoxisch wirkt und nur begrenzt durch konjugation mit glutathion entgiftet werden kann. diese konjugationsleistung scheint der fetus mit fortschreitender schwangerschaft besser zu bewältigen. die metabolisierung des paracetamols erfolgt in der fetalen leber 10-mal langsamer als in der des erwachsenen. hierdurch bildet der fetus weniger toxische metabolite und ist dadurch relativ geschützt. vom teratologischen beratungszentrum newcastle in großbritannien wurden 450 schwangere mit paracetamol-überdosis erfasst und nachverfolgt (mcelhatton 2001) , davon 40 mit kombinationspräparaten, die zusätzlich dextropropoxyphen enthielten. in 140 fällen erfolgte die einnahme im 1. trimenon. insgesamt 11 kinder wiesen verschiedenartige fehlbildungen auf, die nicht für eine kausalbeziehung zwischen einnahme und auffälligkeit sprachen, zumal die exposition jenseits des 1. trimenons lag. die spontanabortrate war mit 8-10 % nicht erhöht. keines der neugeborenen oder der untersuchten abortierten feten wies zeichen einer leber-oder nierenschädigung auf. dies trifft auch auf ein kind zu, dessen mutter in schwangerschaftswoche 32/33 zweimal so hohe paracetamoldosen eingenommen hatte, dass eine lebertransplantation erwogen wurde (rosevaer 1989) . soweit daten zu acetylcystein als antidot vorliegen, deuten diese nicht auf eine spezifische entwicklungstoxische eigenschaft hin. empfehlung für die praxis: wie auch außerhalb einer schwangerschaft muss in abhängigkeit von der serumkonzentration des paracetamols unverzüglich mit einer antidottherapie begonnen werden, und zwar im interesse von mutter und fetus. ein aufschieben dieser therapie hat in einzelnen fällen zum absterben des fetus bzw. zum tod der mutter geführt. andererseits gibt es keine hinweise auf fetotoxizität, wenn toxische symptome bei der mutter ausbleiben oder toxische serumspiegel nicht erreicht werden. daher ist in den weitaus meisten fällen einer paracetamol-überdosis ein schwangerschaftsabbruch aus furcht vor einer schädigung der frucht nicht gerechtfertigt. podophyllotoxin, in hoher dosis äußerlich aufgetragen, hat bei einzelnen schwangeren zu psychiatrischer symptomatik geführt, zu einem mütterlichen todesfall, einem intrauterinen fruchttod (stoudemire 1981 , slater 1978 , montaldi 1974 , chamberlaine 1972 , ward 1954 ) und einer fehlbildung mit beteiligung von extremitäten, herz und ohr nach exposition zwischen schwangerschaftswoche 5 und 9 ). g 2. über etwa 90 fälle von schlangenbissen bei schwangeren wird in der literatur berichtet, nur in einem teil davon wird der verlauf detailliert beschrieben (sebe 2005b, langley 2004 , nasu 2004 , dao 1997 , pantanowitz 1996 . außerdem gibt es einige wenige kasuistiken zu spinnenbissen (pantanowitz 1996) . genaueres zur wirksamkeit der verschiedenen speziesabhängigen neurotoxine, zytotoxine und hämatotoxine auf den fetus ist nicht bekannt. berichtet wird z. b. über vier frauen in sri lanka, von denen in schwangerschaftswoche 32 bis 34 je zwei von kobras und vipern gebissen wurden (james 1985) . drei der frauen zeigten keine vergiftungssymptome, sie bemerkten jedoch übereinstimmend eine starke abnahme der kindsbewegungen. auch die fetale herzfrequenz sank. nach gabe spezifischer antiseren normalisierten sich kindsbewegungen und herzfrequenz innerhalb von 24 stunden. diese drei mütter brachten termingerecht gesunde kinder zur welt. die vierte schwangere bemerkte ebenfalls innerhalb der ersten 24 stunden eine verlangsamung der kindsbewegungen, sie wurde jedoch erst mit antiserum behandelt, nachdem sich ein schweres vergiftungsbild mit hämolyse und nierenversagen entwickelt hatte. kurz darauf kam es zu einer totgeburt. die von den schwangeren übereinstimmend beobachtete verminderung der kindsbewegungen zeigt, dass schlangengift den fetus anscheinend schon bei niedrigen dosen erreicht, selbst wenn 2.23 zur umwelt gehören die belebte und unbelebte umgebung des menschen. umwelteinflüsse auf die schwangere umfassen fremdstoffe in der atemluft, in der nahrung und auf der haut, im häuslichen umfeld oder am arbeitsplatz. zu den umwelteinflüssen gehören ferner physikalische einwirkungen, wie ionisierende strahlung, elektromagnetische felder, lärm, ernährungs-, freizeit-und arbeitsgewohnheiten. da die wohnung formal betrachtet in deutschland zur umwelt gehört, werden belastungen durch schadstoffe in raumluft durch die umweltgesetzgebung geregelt. g 2.23.1 schadstoffe im umfeld der schwangeren für schadstoffe in der umwelt und chemische substanzen am arbeitsplatz sind auswirkungen auf die vorgeburtliche entwicklung viel schlechter untersucht als für arzneimittel. eine unterscheidung zwischen umwelt-und arbeitsplatzschadstoffen ist nicht sinnvoll, da viele umweltschadstoffe aus industriellen prozessen freigesetzt werden. bei der risikobewertung von umweltchemikalien kann deshalb zunächst auf die informationen über gesundheitliche risiken von industriechemikalien zurückgegriffen werden. diese sind nach dem arbeitsschutzgesetz vorgeschrieben und werden im so genannten "sicherheitsdatenblatt" zusammengefasst. toxikologische informationen beruhen überwiegend auf ergebnissen von tierexperimenten, nur in einigen fällen liegen zusätzlich ergebnisse von retrospektiven, epidemiologischen studien vor, bei denen meistens aussagefähige daten zum ausmaß der exposition fehlen (übersicht in , spielmann 1986 . da nach der gesetzlichen regelung für industriechemikalien nur bei einem begründeten verdacht reproduktionstoxikologische tierexperimente durchgeführt werden müssen, fehlen nach schätzungen des bundesinstitutes für risikobewertung (bfr) diese daten bei 80 % der ca. 30.000 industriechemikalien, die in der eu in einer menge von jährlich mehr als 1 tonne produziert werden (höfer 2004) . grundsätzlich ist es beruhigend, dass mit den verfügbaren epidemiologischen methoden kein erhöhtes fehlbildungsrisikos bei der in mitteleuropa durchschnittlich vorkommenden exposition mit chemikalien am arbeitsplatz und in der umwelt feststellbar ist. kritischer zu sehen sind allerdings industriegebiete, in denen beispielsweise schwermetalle, persistierende organochlorverbindungen oder organische lösungsmittel verarbeitet werden mit potenziellen auswirkungen auf die fertilität, die abortrate sowie die entwicklung der hirnleistung und des immunsystems, symptome, die teilweise erst im kindes-oder erwachsenenalter nachweisbar sind. in einzelfällen wurde bei vergiftungen der mutter mit solchen stoffen auch das ungeborene kind schwer geschädigt. deshalb sind der sorglose umgang mit schadstoffen und die unkritische weiterbeschäftigung einer schwangeren an potentiell belasteten arbeitsplätzen weder aus medizinischer noch aus arbeitsrechtlicher sicht akzeptabel. in deutschland werden die maximalen arbeitsplatzkonzentrationen (mak-werte) für industriechemikalien von der mak-werte-kommission der deutschen forschungsgemeinschaft (dfg) geregelt (dfg 2005) . seit 1986 gibt die mak-werte-kommission auch empfehlungen für den umgang mit industriechemikalien in der schwangerschaft am arbeitsplatz, die kontinuierlich überarbeitet werden, und die wir auch als grundlage der bewertung ansehen. in diesem kapitel werden einleitend die wichtigsten schadstoffe mit ihren wirkungen in der gravidität vorgestellt und anschließend werden die mak-werte in der schwangerschaft, soweit sie vergeben wurden, diskutiert. g 2.23.2 quecksilber (siehe auch abschnitt 4.18.2) im gegensatz zu den in der bundesrepublik deutschland durchschnittlich gemessenen konzentrationen von x 1 ? g/l quecksilber (hg) im blut, finden sich in schweden und japan aufgrund häufigeren verzehrs belasteter meerestiere höhere durchschnittswerte, bei den inuit (eskimos) wurden sogar über 16 ? g/l hg im mütterlichen blut und über 35 ? g/l im nabelschnurblut gemessen (bjerregard und hansen 2000) . anorganisches hg kann die plazenta kaum überwinden, reichert sich aber in ihr an. hingegen gelangt organisches hg fast ungehindert durch die plazenta. hg findet sich vorwiegend in gehirn, leber und niere. die höhe der hg-konzentration in den organen des fetus und neugeborenen korreliert mit der zahl der amalgam-füllungen der mutter (schiele 1999) . eine neuere untersuchung zum hg-gehalt im haar von neugeborenen und ihren müttern findet zwar erhöhte konzentrationen bei amalgam-füllungen, jedoch keine unterschiede zwischen frauen mit alten füllungen und frauen, die während der schwangerschaft neue amalgam-füllungen erhielten . schwere vorgeburtliche schädigungen durch organisches hg wurden in den 50er jahren in minamata, japan beobachtet. stark hg-haltige industrieabwässer führten nach methylierung des hg durch bakterien zur anreicherung in fischen. mütter, die vor und besonders während der schwangerschaft hochgradig belastete fische verzehrt hatten, bemerkten meist nur leichte parästhesien. nach überwiegend normalem schwangerschaftsverlauf waren die kinder bei der geburt unauffällig, aber im alter von etwa sechs monaten entwickelten sie zeichen einer beginnenden, z. t. letal verlaufenden zerebralparese. neben diesen symptomen der fetotoxischen 7 eine so genannte "amalgam-entgiftung" mit chelatbildnern (siehe kapitel 2.22) ist in der schwangerschaft zu unterlassen, weil amalgam-plomben keine quecksilber-vergiftung verursachen. außerdem ist der häufig empfohlene chelatbildner dmps beim fetus nicht wirksam, weil die besonders problematischen zns-depots nicht erreicht werden. (sterling 1986) . mit wesentlich größerem forschungsaufwand wurde dem verdacht nachgegangen, dass amerikanische vietnamkriegsveteranen unter fruchtbarkeitsstörungen durch das hantieren mit agent orange litten. ein beweis hierfür konnte nicht erbracht werden. in seveso (italien) wurden 1976 bei einem unfall in einer chemiefabrik dioxine, u. a. das später als "sevesogift" bezeichnete tcdd (2,3,7,8-tetrachlor-p-dibenzodioxin) freigesetzt. mehrere untersuchungen an den damals geborenen kindern kamen zu widersprüchlichen ergebnissen. dabei ist zu berücksichtigen, dass viele schwangerschaften aus angst vor fehlbildungen abgebrochen wurden. eine tera-retardierung, mikrozephalie, dem fetalen alkoholsyndrom ähnelnde kraniofaziale dysmorphien, zns-funktionsstörungen und auch fälle von partieller schädel/hirnagenesie wurden in diesem zusammenhang beobachtet. in den meisten fällen handelte es sich um einen abusus mit toluol (übersicht in . eine häufung von zns-fehlbildungen wurde auch bei kindern von müttern beschrieben, die beruflich mit lösungsmitteln exponiert waren. außerdem wurde über ein leicht erhöhtes risiko für kardiovaskuläre anomalien und inguinalhernien nach beruflicher exposition der mutter mit kohlendisulfid berichtet und über ein erhöhtes risiko für gaumenspalten, kardiovaskuläre, intestinale und multiple fehlbildungen bei nicht spezifiziertem gewerblichem lösungsmittelkontakt (laumont 1996) . andere entwicklungsstörungen sowie früh-und fehlgeburten wurden ebenfalls im zusammenhang mit gewerblicher exposition publiziert. mehrere untersuchungen beschäftigen sich mit der tätigkeit in chemischen reinigungen (z. b. doyle 1997 , zielhuis 1989 . die ergebnisse sind widersprüchlich, z. b. scheint die abortrate bei frauen, die mit chlorierten lösungsmitteln arbeiten, erhöht zu sein (mcmartin 1998 , kyyrönen 1989 . eine erhöhte fehlbildungsrate oder ein typisches fehlbildungsmuster ließen sich bisher jedoch nicht belegen (mcmartin 1998) . in kalifornien wurden wiederholt auswirkungen einer trinkwasserkontamination mit trichlorethen auf die vorgeburtliche entwicklung untersucht. entgegen anfänglichen verdachtsmeldungen gab es keinen signifikanten anstieg pränataler entwicklungsstörungen. einschränkungen in der sprachentwicklung im zusammenhang mit beruflicher lösungsmittelexposition der mutter beschreibt eine studie mit 33 kindern im alter von 3 bis 7 jahren (siambani 2000) . eine metaanalyse von studien aus den jahren 1996-2003, bei der 380.000 schwangerschaften erfasst wurden, ergab hinweise darauf, dass kinder von vätern mit beruflichem kontakt zu organischen lösungsmitteln ein gering erhöhtes risiko für neuralrohrdefekte haben, auch wurden tendenziell mehr fehlgeburten beobachtet (logman 2005) . empfehlung für die praxis: die daten zur pränatalen toxizität von organischen lösungsmitteln lassen keine abschließende beurteilung zu. bei konsequenter einhaltung arbeitshygienischer vorgaben sowie bei gelegentlichen arbeiten mit lösungsmitteln im haushalt (reinigung, renovierung) ist mit einem messbaren anstieg des fehlbildungsrisikos nicht zu rechnen. weil schwangerschaftskomplikationen und geringe funktionsdefizite unzureichend oder gar nicht untersucht sind oder zu widersprüchlichen ergebnissen führten, sollen schwangere nicht mit organischen lösemitteln arbeiten, wenn wiederholt mit "quantitativem" kontakt gerechnet werden muss. im gewerblichen bereich sollte eine individuelle expositionsabschätzung veranlasst werden. (dabrowski 2003) . mehrere untersuchungen haben sich mit der auswirkung von trinkwasserchlorierung beschäftigt, die zur kontamination des wassers mit trihalomethanen (chloroform, bromoform u. a.) führen kann. als mögliche folge wurden sowohl eine erhöhte fehlbildungsrate, speziell neuralrohrdefekte, ein verringertes geburtsgewicht, verringerte körperlänge und kopfumfang sowie frühgeburtlichkeit und höhere abortraten diskutiert. in diesen retrospektiven studien fehlen meistens informationen über die tatsächliche exposition der schwangeren und im vergleich zu nicht exponierten kontrollgruppen waren die relativen risiken nur gering erhöht (källén 2000 , nieuwenhuijsen 2000 . umweltbelastungen mit arsen-und bor-verbindungen sowie mit phthalaten, bei denen estrogenartige nebenwirkungen vermutet werden, haben zur reproduktionstoxizität beim menschen keine klinisch relevanten ergebnisse erbracht , moore 2000 , desesso 1998 , fail 1998 . ein tendenziell verringertes geburtsgewicht wurde mit zunehmender kohlenmonoxid-konzentration als indikator für luftverschmutzung festgestellt. eine retrospektive studie hat die geburtsdaten von über 125.000 kindern im raum los angeles und messdaten von monitorstationen in wohnortnähe ausgewertet (ritz 1999) . obwohl der beobachtete trend biologisch plausibel erscheint, wurden in dieser studie weitere relevante faktoren wie (passiv-)rauchen unzureichend dokumentiert. acrylamid ist weit verbreitet in industriellen prozessen. generell kann es in hohen dosen neurotoxisch wirken. acrylamid findet sich im zigarettenrauch und lässt sich im blut von rauchern in erhöhtem maße nachweisen. außerdem wird es in verschiedenen nahrungsprodukten wie z. b. kartoffelchips und pommes frites gefunden. studien zu auswirkungen acrylamidhaltiger nahrung in der schwangerschaft beim menschen gibt es bislang nicht. es gibt auch keine fallberichte, die schädigungen neugeborener beschreiben. in tierversuchen bzw. zellkulturexperimenten hat sich acrylamid als mutagen, karzinogen und neurotoxisch erwiesen. widersprüchlich sind die ergebnisse von studien, die den einfluss von chemischem giftmüll auf den schwangerschaftsverlauf untersuchen. eine studie aus kalifornien berichtet darüber, dass neuralrohrdefekte und herzanomalien häufiger bei kindern von frauen auftraten, die in der nähe von giftmülldeponien wohnten, und dass mit der ent-schwellendosen nicht definieren, daher werden keine mak-werte festgesetzt. für schwangere gibt es keine eigenen mak-werte, stattdessen wird für einzelne chemische stoffe angegeben, ob bei einhaltung des mak-wertes ein fruchtschädigendes risiko besteht oder nicht. der begriff "fruchtschädigend" wird dabei sehr weit definiert und umfasst jeden effekt eines stoffes, der ein abweichen von der normalentwicklung hervorruft und "prä-oder postnatal zum tod oder zu permanenten morphologischen oder funktionellen schädigungen der leibesfrucht führt." die bewerteten substanzen werden in vier kategorien (a-d) eingestuft. mit krebserzeugenden stoffen muss in der schwangerschaft jeglicher kontakt gemieden werden. wie weiter oben angesprochen, gibt es nur für wenige arbeits-bzw. schadstoffe ausreichende erfahrungen beim menschen, die eine differenzierte risikobewertung ermöglichen. die anzahl der in tabelle 2.5 wiedergegebenen stoffe ist, gemessen an der gesamtzahl der weltweit produzierten arbeits-und schadstoffe sehr klein und die humantoxikologischen daten sind in den meisten fällen unzureichend. das muss besonderes bei den substanzen der gruppe c berücksichtigt werden, bei denen bei einhaltung des mak-wertes ein fruchtschädigendes risiko ausgeschlossen wird. die orientierung am so genannten no observed adverse effect level (noael), der in tierversuchen ermittelt wird, ist in den meisten fällen für die beim menschen übliche komplexe expositionssituation nicht ausreichend, insbesondere weil noael-werte nur in ausnahmefällen reproduktionstoxikologisch fundiert sind. die einstufung von 114 in der schwangerschaft unbedenklichen stoffen in die gruppe c (tabelle 2.5) ist bemerkenswert, denn experten in anderen ländern haben sich bisher gescheut, aufgrund von tierexperimenten und den meist unvollständigen epidemiologischen daten ein risiko für die schwangerschaft auszuschließen. bei genauer analyse dieser gruppe überrascht, dass im jahr 2005 auch stoffe mit krebserzeugenden eigenschaften in gruppe c eingestuft wurden, für die ein nicht genotoxischer wirkungsmechanismus angenommen wird. dazu gehören u. a. formaldehyd und das "sevesogift" dioxin bzw. tcdd. weitere probleme bei der einstufung in gruppe c werden dadurch belegt, dass von den 25 stoffen, die vor 20 jahren in die gruppe c eingestuft waren, mehr als 10 inzwischen anderen gruppen zugeordnet wurden, und zwar in die gruppe der krebserzeugenden bzw. krebsverdächtigen arbeitsstoffe, wie z. b. 1,2-dichlorethan, malathion und parathion. auch toluol wird der gruppe c zugeordnet, obwohl es embryotoxisch wirkt, wenn es von abhängigen frauen missbräuchlich in konzentrationen inhaliert wird ("sniffing"), die den mak-wert in manchen fällen nur um das 5fache überschritten haben . es ist daher problematisch, diesem stoff aufgrund der beim menschen sporadisch erhobenen daten eine unbedenklichkeit bei einhalten des mak-wertes zu attestieren. organische quecksilber-verbindungen (methylquecksilber) waren die einzige stoffgruppe, die ursprünglich in schwangerschaftsgruppe a der mak-werte-liste eingestuft wurde. inzwischen werden sie den krebserzeugenden stoffen zugeordnet (siehe oben). es mag überraschen oder beruhigend wirken, dass bis heute nur 14 industriechemikalien in schwangerschaftsgruppe b eingestuft wurden (tabelle 2.5). diese stoffe werden auch bei einhaltung der üblichen arbeitsschutzbedingungen als potenziell fruchtschädigend angesehen. ein risiko ist auch bei exposition außerhalb des arbeitsplatzes gegeben, wenn überdurchschnittliche mengen über die nahrung aufgenommen werden. zu dieser gruppe gehören u. a. polychlorierte biphenyle (pcb), deren toxische wirkung in der schwangerschaft weiter oben beschrieben wird. schwangere dürfen nach ansicht der mak-werte-kommission nicht mit krebserzeugenden stoffen in berührung kommen. eine ausnahme bilden seit 2005 die nicht genotoxisch wirkenden karzinogene, für die eine schwellendosis angenommen wird. sie werden schwangerschaftsgruppe c zugeordnet, für die "ein risiko der fruchtschädigung bei einhaltung des mak-wertes und des bat-wertes nicht befürchtet werden muss." (dfg 2005) . zu diesen stoffen mit nicht genotoxischen, krebserzeugenden eigenschaften gehören u. a. das dioxin tccd und formaldehyd. insbesondere die erfahrungen mit dem hormonpräparat diethylstilbestrol, das nach vorgeburtlicher exposition bei den töchtern nach der pubertät u. a. zu scheidenkarzinomen führte, hat die aufmerksam-keit auf das risiko einer "transplazentaren karzinogenese" gelenkt. mit mehr als 200 stoffen ist die gruppe der krebserzeugenden und krebsverdächtigen arbeitsstoffe die umfangreichste risikogruppe im abschnitt mak-werte. zu den chemikalien, die beim menschen nicht nur fruchtschädigende, sondern möglicherweise auch krebserzeugende oder tumorfördernde wirkungen haben, gehören u. a. organisches quecksilber und die organischen lösungsmittel trichlorethen (tri) und tetrachlorethen (per). allerdings sind beim menschen in der schwangerschaft vermittelte karzinogene effekte wie beim diethylstilbestrol bisher bei keiner anderen substanz nachgewiesen worden. die auswirkungen von keimzellmutationen umfassen sowohl genetisch bedingte variationen ohne krankheitswert als auch fruchtbarkeitsstörungen, fruchttod, fehlbildungen und erbkrankheiten. aufgrund der zufälligkeit der verteilung von mutationsereignissen im erbgut (genom) ist nicht zu erwarten, dass ein mutagener stoff eine substanzspezifische fehlbildung hervorruft. deshalb ist der nachweis zwischen einer exposition und dem auftreten von erbkrankheiten beim menschen kaum zu erbringen. in dieser situation kann man keimzellmutagene bisher nur aufgrund erhöhter mutationsraten bei den nachkommen exponierter versuchstiere erkennen. die von der mak-werte-kommission benannten substanzen sind in anlehnung an krebserzeugende stoffe in fünf kategorien eingeteilt (tabelle 2.6). obwohl bisher der nachweis fehlt, dass durch keimzellmutagene beim menschen genauso wie bei versuchstieren die nachfolgenden generationen geschädigt werden können, sollten schwangere und frauen im gebärfähigen alter jeden kontakt mit solchen stoffen vermeiden. die keimzellmutagene werden in weitgehender analogie zu den kategorien für krebserzeugende arbeitsstoffe in folgende kategorien eingeteilt: keimzellmutagene, deren wirkung anhand einer erhöhten mutationsrate unter den nachkommen exponierter personen nachgewiesen wurde. bisher wurde noch kein chemischer stoff dieser kategorie zugeordnet. keimzellmutagene, deren wirkung anhand einer erhöhten mutationsrate unter den nachkommen exponierter säugetiere nachgewiesen wurde. empfehlung für die praxis: die übliche exposition mit ionisierender strahlung in der umwelt erfordert keine konsequenzen während der schwangerschaft. dies betrifft auch die höhenstrahlung bei flugreisen und die regional unterschiedliche radon-und andere hintergrundstrahlung. nahrungsmittel, von denen eine anreicherung radioaktiver nuklide bekannt ist, sollten selbstverständlich gemieden werden. g 2.23.9 elektromagnetische felder mögliche auswirkungen elektromagnetischer felder auf die schwangerschaft wurden wiederholt diskutiert. methodische schwierigkeiten mit der definition von exposition und potenziellen effekten erschweren jedoch schlussfolgerungen aus den bisher vorliegenden, meist unbedenklichen ergebnissen. elektromagnetische felder wurden beispielsweise im zusammenhang mit elektrisch beheizten wasserbetten, elektrischen heizdecken und anderen geräten untersucht. sowohl eine leicht erhöhte abortrate als auch harnwegsanomalien wurden in einzelnen untersuchungen beobachtet, allerdings ist die einwirkung anderer begleitfaktoren nicht auszuschließen (übersicht in . speziell mit dem gebrauch von heizdecken beschäftigt sich eine studie an 530 schwangeren . entwicklungstoxische effekte wurden nicht nachgewiesen. auch bei einer wohnung in der nähe von hochspannungsleitungen konnten bisher keine störungen des schwangerschaftsverlaufs nachgewiesen werden (blaasaas 2004 . zu den auswirkungen von mobiltelefonnutzung und den digitalen mobiltelefonsendern in wohnraumnähe 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reuptake inhibitors during pregnancy and breastfeeding: a review and clinical aspects serious life events and congenital malformations: a national study with complete follow-up citalopram in pregnancy and lactation birth defects and drugs in pregnancy placental passage of antidepressant medications aktuelle arzneitherapie der schizophrenie: empfehlungen für den allgemeinarzt. arzneiverordnung in der paroxetin-entzugs-syndrom als differenzialdiagnose der akuten neonatalen enzephalitis? ntp-cerhr expert panel report on reproductive and developmental toxicity of fluoxetine prospective multicentre study of pregnancy outcome after lithium exposure during first trimester paroxetine withdrawal in a neonate with historical and laboratory confirmation a] neonate characteristics after maternal use of antidepressants in late pregnancy fluoxetine use in early pregnancy lithium therapy and congenital malformations fetal abnormalities associated with highdose tranylcypromine in two consecutive pregnancies (abstract) suspected congenital sertraline dependence mirtazapine use in two pregnant women: is it safe? healthy outcome under olanzapine-treatment in a pregnant woman neonatal toxicity and transient neurodevelopmental deficits following prenatal exposure to lithium: another clinical report and a review of the literature einfluss von psychopharmaka auf reproduktion und kontrazeption pregnancy outcome following maternal use of the new selective serotonin reuptake inhibitors neurodevelopment in late infancy after prenatal exposure to benzodiazepines -a prospective study teratogenic effects of benzodiazepine use during pregnancy effects of exposure to selective serotonin reuptake inhibitors during pregnancy on serotonergic symptoms in newborns and cord blood monoamine and prolactin concentrations antipsychotics and the treatment of women with psychosis clinical antipsychotic trials of intervention effectiveness (catie) investigators. effectiveness of antipsychotic drugs in patients with chronic schizophrenia clonazepam use in pregnancy and the risk of malformations the use of lithium and management of women with bipolar disorder during pregnancy and lactation the safety of risperidone: a post-marketing study on 7684 patients olanzapine in pregnancy risks associated with selective serotonin reuptake inhibitors in pregnancy lethargy in a newborn: lithium toxicity or lab error? neurodevelopmental outcome of infants and toddlers exposed prenatally to selective serotonin reuptake inhibitors the effects of benzodiazepine use during pregnancy and lactation the use of phenothiazines during pregnancy and lactation the outcome of pregnancy in 689 women exposed to therapeutic doses of antidepressants. a collaborative study of the european network of significant changes in antipsychotic drug use during pregnancy pregnancy outcome of women using atypical antipsychotic drugs: a prospective comparative study necrotizing enterocolitis in a newborn: maternal psychotropic drugs suspected potenzial fluoxetine chloride (prozac) toxicity in a newborn effects of prenatal meprobamate and chlordiazepoxide hydrochloride on human embryonic and fetal development paroxetine use throughout pregnancy: does it pose any risk to the neonate? neonatal signs after late in utero exposure to serotonin reuptake inhibitors olanzapine and pregnancy child development following exposure to tricyclic antidepressants or fluoxetine throughout fetal life: a prospective, controlled study neurodevelopment of children exposed in utero to antidepressant drugs pain reactivity in 2-month-old infants after prenatal and postnatal selective serotonin reuptake inhibitor medication exposure pharmacologic factors associated with transient neonatal symptoms following prenatal psychotropic medication exposure association of maternal sertraline (zoloft) therapy and transient neonatal nystagmus pregnancy outcome following gestational exposure to venlafaxine: a multicenter prospective controlled study is benzodiazepine use during pregnancy really teratogenic? prospective assessment of pregnancy outcome following first trimester exposure to benzodiazepines pregnancy outcome following first-trimester exposure to fluoxetine (prozac) severe and prolonged sedation in five neonates due to persistence of active diazepam metabolites case report and review of the perinatal implications of maternal lithium use no complications with risperidone treatment before and throughout pregnancy and during the nursing period treating depression in pregnancy prenatal exposure to benzodiazepines: a case-control study. vortrag 10. jahreskonferenz des european network of teratology information services mirtazapine (remergil) for treatment resistant hyperemesis gravidarum: rescue of a twin pregnancy effectiveness and cost of olanzapine and haloperidol treatment of schizophrenia mirtazapine: treatment of depression, anxiety, and hyperemesis gravidarum in the pregnant patient. a report of 7 cases neonatal convulsions and subarachnoidal hemorrhage after in utero exposure to paroxetine selective serotonin reuptake inhibitors in pregnant women and neonatal withdrawal syndrome: a database analysis alprazolam exposure during early human pregnancy toxic neonatal effects following maternal clomipramine therapy update on new developments in the study of human teratogens outcomes of prenatal antidepressant exposure chloral hydrate, methylmercury hydroxide and ethidium bromide affect chromosome segregation during meiosis of saccharomyces cerevisiae fluoxetine hydrochloride (prozac) toxicity in a neonate first-trimester exposure to alprazolam pregnancy outcome of women exposed to azathioprine during pregnancy: a prospective multicenter study. (abstract) the reproductive effects of beta interferon therapy for multiple sclerosis teratogen update: reproductive risks of leflunomide (arava tm ); a pyrimidine synthesis inhibitor: counseling women taking leflunomide before or during pregnancy and men taking leflunomide who are contemplating fathering a child drugs in pregnancy and lactation hydroxychloroquine and lupus pregnancy: review of a series of 36 cases transplacental passage of recombinant human granulocyte colony-stimulating factor in women with an imminent preterm delivery the use of disease modifying antirheumatic drugs in women with rheumatoid arthritis of childbearing age: a survey of practice patterns and pregnancy outcomes huong du lt. safety of hydroxychloroquine in pregnant patients with connective tissue diseases safety of hydroxychloroquine in pregnant patients with connective tissue diseases maternal azathioprine therapy and depressed haematopoiesis in the babies of renal allograft patients paternal and maternal exposure to leflunomide: pregnancy and neonatal outcome wilson's disease treated with trientine during pregnancy immunologic evaluation during the first year of life of infants born to cyclosporine-treated female kidney transplant recipients: analysis of lymphocyte subpopulations and immunoglobulin serum levels pregnancy and wilson's disease the safety of 6-mercatopurine for childbearing patients with inflammatory bowel disease: a retrospective cohort study neonatal lupus and iugr following alpha-interferon therapy during pregnancy the ototoxicity of chloroquine phosphate pregnancy after liver transplantation under tacrolimus pregnancy after liver transplantation with tacrolimus immunosuppression: a singel center's experiencee update at 13 years pregnancy after kidney and kidneypancreas transplantation under tacrolimus: a single center's experience copolymer 1 reduces relapse rate and improves disability in relapsing-remitting multiple sclerosis: results of a phase iii multicenter, double-blind, placebo-controlled trial otterblad olausson p. pregnancy outcome after maternal organ transplantation in sweden outcome of pregnancy in women receiving infliximab for the treatment of crohn's disease and rheumatoid arthritis review of the course and outcome of 100 pregnancies in 84 women treated with tacrolimus levamisole (decartis ® ) treatment during pregnancy systemic lupus erythematosus flares during pregnancy ocular toxicity and antenatal exposure to chloroquine or hydroxychloroquine for rheumatic diseases analysis of 629 pregnancy outcomes in transplant recipients treated with sandimmun mycophenolate mofetil in pregnancy after renal transplantation: a case of major fetal malformations pregnancy outcome following first trimester exposure to chloroquine intentional infliximab use during pregnancy for induction of maintenance of remission in crohn's disease. aliment prenatal exposure to penicillamine and oral clefts: case report morbus wilson und schwangerschaft. literaturübersicht und kasuistische mitteilung teratogen update: thalidomide: a review, with a focus on ocular findings and new potential uses the effect on the fetus of medications used to treat pregnant inflammatory bowel-disease patients follow-up of infants exposed to hydroxychloroquine given to mothers during pregnancy and lactation pregnancy outcome in liver transplant recipients the re-emergence of thalidomide: results of a scientific conference azathioprine, mercaptopurine and birth outcome: a population-based cohort study neurodevelopment in children exposed in utero to cyclosporine and azathioprine following maternal renal transplant: preliminary results hydroxychloroquine in pregnant patients with systemic lupus erythematosus immunmodulatoren zur therapie der multiplen sklerose bei frauen im fertilen alter kidney transplantation during the first trimester of pregnancy: immunosuppression with mycophenolate mofetil, tacrolimus, and prednisone infant with severe penicillamine embryopathy born to a women with wilson disease teratogen uptake: azathioprine and 6-mercaptopurine pregnancies following liver transplantation -how safe are they? a report of 19 cases under cyclosporine a and tacrolimus long-term follow-up of children with in utero exposure to immunosuppressives hepatoblastoma in a 2-year-old child of a liver-transplanted mother teratogen update: penicillamine prophylactic granulocyte colony-stimulating factor treatment for acquired chronic severe neutropenia in pregnancy kupfer und penicillamin in der schwangerschaft successful ovulation induction, conception, and normal delivery after chronic therapy with etanercept: a recombinant fusion anti-cytokine treatment for rheumatoid arthritis successful pregnancies and abortions in symptomatic and asymptomatic wilson's disease hypothesis: thalidomide embryopathy-proposed mechanism of action offspring of male and female parents with thalidomide embryopathy: birth defects and functional anomalies cardiotoxic tranplacental effect of idarubicin administered during the second trimester of pregnancy methotrexate/misoprostol embryopathy: report of four cases resulting from failed medical abortion successful pregnancy in acute promyelocytic leukemia pregnancy under treatment of imatinib and successful labor in a patient with chronic myelogenous leukemia (cml) successful outcome with anagrelide in pregnancy managing hairy cell leukemia in pregnancy combined chemotherapy and radiotherapy during conception and two trimesters of gestation in a woman with metastatic breast cancer management of chemotherapy in a pregnancy complicated by a large neuroblastoma teratogenic effects in a case of maternal treatment for acute myelocytic leukaemia -neonatal und infantile course growth and development of children of mothers treated with chemotherapy during pregnancy: current status of 43 children non-hodgkin's lymphomas and pregnancy: presentation of 16 cases mitoxantrone and etoposide in breast milk non-hodgkin's lymphoma in pregnancy adult and two children with fetal methotrexate syndrome management of breast cancer during pregnancy using a standardized protocol pregnancy outcome following cancer chemotherapy genetic effects of radiotherapy for childhood cancer drugs in pregnancy and lactation full-term pregnancy in a patient diagnosed with acute leukemia treated with a protocol including vp-16 multiple congenital anomalies associated with weekly low-dose methotrexate treatment of mother absence of birth defects in offspring of women treated with dactinomycin use of chemotherapy during human pregnancy successful treatment of acute promyelocytic leukaemia during pregnancy the use of disease modifying antirheumatic drugs in women with rheumatoid arthritis of childbearing age: a survey of practice patterns and pregnancy outcomes prenatal diagnosis of methotrexate embryopathy successful fetal outcome after exposure to idarubicin and cytosine-arabinoside during the second trimester of pregnancy -a case report cyclophosphamide for lupus during pregnancy acute promyelocytic leukemia during pregnancy: report of 3 cases goldenhar's syndrome associated with tamoxifen given to the mother during gestation (letter) vinorelbin in pregnancy fertility and ovarian function are preserved in women treated with an intensified regimen of cyclophosphamide, adriamycin, vincristine and prednisone (mega-chop) for non-hodgkin lymphoma successful pregnancy during chemotherapy for acute leukemia procarbazine in pregnancy metastatic breast cancer in pregnancy: first case of chemotherapy with docetaxel developmental delay in fetal aminopterin/methotrexate syndrome hydroxyurea use during pregnancy: a case report in sickle cell disease and review of the literature chemotherapy for metastatic melanoma during pregnancy methotrexate exposure prior to and during pregnancy anagrelide therapy in pregnancy: report of a case of essential thrombocythemia high total dose 5-fluorouracil treatment during pregnancy an endodermal sinus tumor diagnosed in pregnancy: case report and review of the literature apparent cyclophosphamide (cytoxan) embryopathy: a distinct phenotype? non-hodgkin-lymphom und schwangerschaft successful treatment of acute promyelocytic leukemia in pregnancy with all-trans retinoic acid pregnancy outcomes following treatment of cancer clinical teratology counseling and consultation case report: low dose methotrexate exposure in the early weeks of pregnancy acute leukemia and pregnancy management of an advanced ovarian cancer at 15 weeks of gestation: case report and literature review the safety of 6-mercatopurine for childbearing patients with inflammatory bowel disease: a retrospective cohort study chemotherapy with epirubicin and paclitaxel for breast cancer during pregnancy: case report and review of the literature passage transplacentaire de l'épirubincine doxorubicin in the first trimester of pregnancy teratogenic effects of combination chemotherapy anthracyclines during pregnancy: embryo-fetal outcome in 160 patients cis-platinum neoadjuvant chemotherapy in a pregnant woman with invasive carcinoma of the uterine cervix chemotherapy for breast carcinoma during pregnancy multimodal cancer chemotherapy during the first and second trimester of pregnancy: a case report pregnancy associated breast cancer: a case report successful chemotherapy including epirubicin in a pregnant non-hodgkin's lymphoma patient paclitaxel chemotherapy in a pregnant patient with bilateral breast cancer congenital anomalies in children of patients who received chemotherapy for cancer in childhood and adolescence pregnancy outcome of female survivors of childhood cancer: a report from the childhood cancer survivor study pregnancy outcome of partners of male survivors of childhood cancer survivor study congenital anomalies probably induced by cyclophosphamide acute leukemia during pregnancy: a single institutional experiencee with 17 cases pregnancy outcome after prenatal exposure to bleomycin, etoposide and cisplatin for malignant ovarian germ cell tumors: report of 2 cases teratogenicity of adriamycin successful outcome of pregnancy in chronic myeloid leukaemia treated with imatinib pharmakokinetics of methotrexate in erythrocytes in psoriasis imatinib treatment: specific issues related to safety, fertility, and pregnancy efficacy and safety of a combined rituximab chemotherapy during pregnancy primary ovarian carcinoma during pregnancy mixed germ cell malignancy of the ovary concurrent with pregnancy sinusoidal fetal heart rate pattern during chemotherapy in a pregnant woman with acute myelogenous leukemia tamoxifen as systemic treatment of advanced breast cancer during pregnancy -case report and literature review oat cell carcinoma of the uterine cervix in a pregnant woman treated with cis-diamminedichloroplatinum management of the pregnant patient with hodgkin's disease neonatal effects of breast cancer chemotherapy administered during pregnancy a woman with a balanced autosomal translocation who received chemotherapy while pregnant safety of rituximab therapy during the first trimester of pregnancy: a case history teratogenic effects of first-trimester cyclophosphamide therapy cyclophosphamide therapy in a serious case of lupus nephritis during pregnancy inadvertent 5-fluorouracil treatment in early pregnancy: a report of three cases stage of pregnancy-dependent transplacental passage of 195mpt after cis-platinum treatment outcome of first-trimester exposure to low-dose methotrexate in eight patients with rheumatic disease in utero first trimester exposure to low-dose methotrexate with increased fetal nuchal translucency and associated malformations successful pregnancy after tamoxifen and megestrol acetate therapy for endometrial carcinoma low dose methotrexate in the first trimester of pregnancy: result of a french collaborative study consequences of acute myelogenous leukemia in early pregnancy normal infant after combination chemotherapy including teniposide for burkitt's lymphoma in pregnancy wegener's granulomatosis in pregnancy mcelhatton a review of the reproductive toxicity of methotrexate in human pregnancy congenital anomalies due to attempted abortion with 4-amino pteroylglutamic acid paclitaxel and carboplatin chemotherapy administered during pregnancy for advanced epithelial ovarian cancer fetal renal malformation following treatment of hodgkin's disease during pregnancy management of cancer in pregnancy: a case of ewing's sarcoma of the pelvis in the third trimester infant or mother with malignant disease hydroxyurea in pregnant women with polycythemia vera methotrexate-induced congenital malformations chemotherapy-induced amenorrhea and fertility in women undergoing adjuvant treatment for breast cancer pregnancy outcome after the use of an aromatase inhibitor for ovarian stimulation the effect on the fetus of medications used to treat pregnant inflammatory bowel-disease patients eclampsia after polychemotherapy for nodalpositive breast cancer during pregnancy pregnancy outcome in cancer patients: experience in a large cooperative group fetal marrow suppression after maternal chemotherapy for leukaemia multimodal cancer therapy for breast cancer in first trimester of pregnancy the human teratogenic effect of cyclophosphamide good outcome for infant of mother treated with chemotherapy for ewing sarcoma at 25 to 30 weeks' gestation multiple anomalies in a fetus exposed to low-dose methotrexate in the first trimester treatment of acute myeloid leukemia during the second and third trimesters of pregnancy azathioprine, mercaptopurine and birth outcome: a population-based cohort study neurodevelopment of children exposed in utero to treatment of maternal malignancy non-hodgkin's lymphoma in pregnancy 5-fluorouracil exposure during the period of conception: report on two cases successful treatment of an advanced cystadenocarcinoma in pregnancy with cisplatin, adriamycin and cyclophosphamid (cap) regimen. case report administration of rituximab during the first trimester of pregnancy without consequences for the newborn low dose weekly methotrexate in early pregnancy. a case series and review of literature prenatal detection of multiple fetal anomalies following inadvertent exposure to cyclophosphamide in the first trimester of pregnancy doxorubicin-induced cardiomyopathy during pregnancy: three case reports of anesthetic management for cesarean and vaginal delivery in two kyphoscoliotic patients combined chemotherapy and teratogenicity polycythemia vera and pregnancy: a case report with the use of hydroxyurea in the first trimester assessment of fetal risk associated with exposure to cancer chemotherapy during pregnancy: a multicenter study treatment of acute leukemia during pregnancy: presentation of nine cases teratogen uptake: azathioprine and 6-mercaptopurine methotrexate-induced congenital malformations transplacental effects of maternal cancer chemotherapy. case report acute leukemia during pregnancy: obstetrics management and perinatal outcome of two cases acute leukemia during pregnancy: the toronto leukemia study group experience with long-term followup of children exposed in utero to chemotherapeutic agents acute leukemia and pregnancy -fatal fetal outcome after exposure to idarubicin during the second trimester chemotherapy for breast cancer during pregnancy: an 18-year experience from five london teaching hospitals vacop-b chemotherapy for high grade non-hodgkin's lymphoma in pregnancy radiation and radiomimetic chlorambucil and the fetal retina chemical inducers of ovulation: comparative results teratogenic effects of antileukemic chemotherapy successful pregnancy following continuous treatment with combination chemotherapy before conception and throughout pregnancy chemically induced birth defects chromosomal aberrations in a newborn whose mother received cytotoxic treatment during pregnancy a case of methotrexate embryopathy with holoprosencephaly, expanding the phenotype possible teratogenic effect of chlorambucil on a human fetus transient dilated cardiomyopathy in a newborn exposed to idarubicin and all-trans-retinoic acid (atra) early in the second trimester of pregnancy paclitaxel and platinum chemotherapy for ovarian carcinoma during pregnancy acute leukemia and pregnancy renal agenesis after first trimester exposure to chlorambucil multiple con-genital anomalies in a fetus exposed to 5-fluorouracil during the first trimester genetic effects of radiotherapy for childhood cancer: gonadal dose reconstruction risk of spontaneous abortion among nurses handling antineoplastic drugs 6-mercaptopurine teratogenicity ambiguous genitalia in infant exposed to tamoxifen in utero exposure to hydroxyurea during pregnancy: a case series therapeutic abortion with a folic acid antagonist, 4-amino pteroylglutamic acid, administerd by the oral route the investigation and management of hodgkin's disease in the pregnant patient fetal effects during cyclophosphamide and irradiation therapy platinum based chemotherapy to treat recurrent sertoli-leydig cell ovarian carcinoma during pregnancy anthracyclines in the treatment of malignancy in pregnancy cyclophosphamide, methotrexate and cytarabine embryopathy: is apotosis the common pathway? acute leucemia and pregnancy congenital abnormalities in baby born to cytarabine treated mother attempted abortion with aminopterin herceptin (trastuzumab) therapy during pregnancy: association with reversible anhydramnios fetal methotrexate and misoprostol exposure: the past revisied a single institutional experience with 43 pregnancies in essential thrombocythemia anomalies associated with failed methotrexate and misoprostol termination fetal outcome after in utero exposure to cancer chemotherapy teratogenicity and carcinogenicity in a twin exposed in utero to cyclophosphamide pregnancy outcome in hematologic malignancies neonatal outcome after exposure to indomethacin in utero: a retrospective case cohort study der unwert der oralen tokolyse. vortrag 12. dtsch. kongr. f. perinatale medizin misoprostol exposure during pregnancy: a french collaborative study maternal and fetal cardiovascular effects of transdermal glyceryl trinitrate and intravenous ritodrine overdosage of misoprostol in pregnancy teratogenicity of misoprostol: data from the latin-american collaborative study of congenital malformations (eclamc) effectiveness of nifedipine versus atosiban for tocolysis in preterm labour: a meta-analysis with an indirect comparison of randomised trials nsaid-induced nephrotoxicity from the fetus to the child tokolyse mit einem nitroglycerinpflaster treatment of sexually transmitted bacterial diseases in pregnant women bacterial vaginosis during pregnancy: screen and treat? maternal spermicide use and adverse reproductive outcome: a meta analysis diltiazem for maintenance tocolysis of preterm labor: comparison to nifedipine in a randomized trial congenital abnormalities in brazilian children associated with misoprostol misuse in first trimester of pregnancy pathophysiologie der lungenödementstehung bei der tokolytischen a risk-benefit assessment of therapies for premature labour do tocolytic agents stop preterm labor? a critical and comprehensive review of efficacy and safety limb reduction anomaly after failed misoprostol abortion aktuelle aspekte der thüringer frühgeburtenvermeidungsaktion nicardipine versus salbutamol in the treatment of premature labor. a prospective randomized study vaginal spermicides and congenital disorders bacterial vaginosis: review of treatment -options and potential clinical indications for therapy controversies in tocolytic therapy calcium channel blockers for inhibiting preterm labour (cochrane review) a randomized double-blind study comparing the fetal effects of sulindac to terbutaline during the management of preterm labor efficacy and safety of indomethacin compared with magnesium sulfate in the management of preterm labor: a randomized study indomethacin treatment for polyhydramnios. effective but potentially dangerous? neonatal complications after the administration of indomethacin for preterm labor myocardial infarction during nifedipine therapy for preterm labor epidemiological assessment of misoprostol teratogenicity nifedipine and ritrodine in the management of preterm labor: a randomized multicenter trial effect on normal vaginal flora of three intravaginal microbicidal agents potentially active against human immunodeficiency virus type 1 a double-blind randomized study of fetal side effects during and after short-term maternal administration of indomethacin, sulindac, and nimesulide for the treatment of preterm labour chemically induced birth defects teratogenicity of misoprostol pregnancy outcome after exposure to misoprostol in brazil: a prospective, controlled study neonatal effects after antenatal treatment with indomethacin vs. sulindac (abstract) bolustokolyse in theorie und praxis safety study of nonoxynol-9 as a vaginal micro-bicide: evidence of adverse effects the effect of relcovaptan (sr 49059), an orally active vasopressin v1a receptor antagonist, on uterine contractions in preterm labor indomethacin tocolysis and itraventricular hemorrhage the effect of in utero exposure to indomethacin on the need for surgical closure of a patent ductus arteriosus in the neonate in utero exposure to terbutaline. effects on infant behavior and maternal selfesteem severe hypotension and fetal death due to tocolysis with nifedipine pharmacokinetics of fenoterol in pregnant women die behandlung des spätabortes und der drohenden frühgeburt mit th1165a in kombination mit isoptin who model list of essential medicines the localization and concentration of copper in the fallopian tube in women with or without an intrauterine contraceptive device misoprostol's effect on uterine arterial blood flow and fetal heart rate in early pregnancy timing and magnitude of increases in levothyroxine requirements during pregnancy in women with hypothyroidism american college of obstetricians and gynecologists. acog committee opinion. use of progesterone to reduce preterm birth arbeitsgemeinschaft der wissenschaftlichen medizinischen fachgesellschaften die ärztliche betreuung der schwangeren diabetikerin arbeitsgemeinschaft der wissenschaftlichen medizinischen fachgesellschaften empfehlungen zu diagnostik und therapie des gestationsdiabetes (gdm) antenatal thyrotropin-releasing -hormone to prevent lung disease in preterm infants. north american -thyrotropin-releasing hormone study group choanal atresia associated with prenatal methimazole exposure: three new patients insulin lispro and regular insulin in pregnancy intrauterine exposure to clomiphene and neonatal persistent hyperplastic primary vitreous the treatment of a thyrotropin-secreting pituitary macroadenoma with octreotide in twin pregnancy normal pregnancy in a woman with nesidioblastosis treated with somatostatin analog octreotide nongenital malformations and exposure to progestational drugs during pregnancy: the final chapter of an erroneous allegation (abstract) drugs in pregnancy and lactation is insulin lispro associated with the development or progression of diabetic retinopathy during pregnancy? maternal and fetal thyroid function risk of gnrh agonist administration in early pregnancy in ovulation induction, update 98 maternal corticosteroid use and risk of selected congenital anomalies hypospadias and maternal intake of progestins and oral contraceptives congenital viral infection? diethylstilbestrol (des) (www.cdc.gov/des/) antenatal steroid use is associated with increased gastroesophageal reflux in neonates methimazole embryopathy: delineation of the phenotype collaborative trial of prenatal thyrotropin-releasing hormone and corticosteroids for prevention of respiratory distress syndrome author's response: severe embryopathy and exposure to methimazole in early pregnancy australian collaborative trial of antenatal thyrotropin-releasing hormone: adverse effects at 12-month follow-up pregnancy complications and perinatal outcome in diabetic woman treated with humalog (insulin lispro) or regular human insulin during pregnancy population-based case-control study of teratogenic potential of corticosteroids cardiovascular risk factors after antenatal exposure to betamethasone: 30-year follow-up of a randomised controlled trial twenty-year follow-up of antenatal corticosteroid treatment long-term treatment with cabergoline in pregnancy and neonatal outcome: report of a clinical case use of insulin glargine during pregnancy in a type 1 diabetic woman (letter) teratogen update: antithyroid drugs -methimazole, carbimazole and propylthiouracil adverse effects of prenatal methimazole exposure intellectual capacity of subjects exposed to methimazole or propylthiouracil in utero administration of a gonadotropinreleasing hormone agonist during pregnancy, follow-up of 28 pregnancies exposed to triptorelin comparative placental transport of oral hypoglycemic agents in humans: a model of human placental transfer macrosomia despite good glycaemic control in type i diabetic pregnancy; results of a nationwide study in the netherlands malformations following methimazole exposure in utero: an open issue nonprescription drugs advisory committee and the advisory committee for reproductive health drugs. december 16 carbimazole embryopathy: an emerging phenotype teratogenic potential of corticosteroids in humans repeated antenatal corticosteroids: size at birth and subsequent development the safety and efficacy of insulin analogs in pregnancy insulin lispro therapy in pregnancies complicated by type 1 diabetes: glycemic control and maternal and fetal outcomes the regulation of thyroid function in pregnancy: pathways of endocrine adaptation from physiology to pathology height, weight, and motor-social development during first 18 months of life in 126 infants born to 109 mothers with polycystic ovary syndrome who conceived on and continued metformin through pregnancy pregnancy outcomes among women with polycystic ovary syndrome treated with metformin metformin therapy throughout pregnancy reduces the development of gestational diabetes in women with polycystic ovary syndrome darbepoetin alfa treatment for post-renal transplantation anemia during pregnancy oral hypoglycemic drugs for gestational diabetes (editorial) pregnancy outcome after first trimester exposure to corticosteroids: a prospective controlled study maternal thyroid deficiency during pregnancy and subsequent neuropsychological development of the child methimazole as a teratogenic etiology of choanal atresia/multiple congenital anomaly syndrome cancer risk in women exposed to diethylstilbestrol in utero prenatal exposure to stilbestrol comparison of glyburide and insulin for the management of gestational diabetes in a large managed care organization effects of metformin on early pregnancy loss in the polycystic ovary syndrome severe malformations in infant born to hyperthyroid woman on methimazole cabergoline treatment for a large macroprolactinoma throughout pregnancy hormone therapy during pregnancy and isolated hypospadias: an international case-control study oral contraceptives in the etiology of isolated hypospadias a case of rosiglitazone exposure in the second trimester of pregnancy severe embryopathy and exposure to methimazole in early pregnancy hypospadias in sons of women exposed to diethylstilbestrol in utero: a cohort study glyburide and fetal safety; transplacental pharmacokinetic considerations aplasia cutis congenita after methimazole exposure in utero glyburide for the treatment of gestational diabetes bromocriptine in pregnancy: safety aspects congenital malformations of newborn infants after clomiphen-induced ovulation long-term follow-up of children born after inadvertent administration of a gonadotrophin-releasing hormone agonist in early pregnancy insulin and glyburide therapy: dosage, severity level of gestational diabetes, and pregnancy outcome oral contraceptive use after conception in relation to the risk of congenital urinary tract anomalies normal development after exposure to mifepristone in early pregnancy limb-body wall complex with complete absence of external genitalia after in vitro fertilization maternal diabetes: an independent risk factor for major malformations with increased mortality of affected infants progression of retinopathy during pregnancy in type 1 diabetic women treated with insulin lispro hormonal treatment in pregnancy: a possible risk factor for neuroblastoma prenatal exposure to sex hormones: a case-control study pregnancy outcome in type 1 diabetes mellitus treated with insulin lispro (humalog) the credibility of the actobat follow-up study maternal metabolic control and perinatal outcome in women with gestational diabetes treated with regular or lispro insulin: comparison with non-diabetic pregnant women clomiphene and hypospadias: the necessity to investigate on a detailed level (abstract) antithyroid drug treatment of graves' disease in pregnancy: long term effects on somatic growth, intellectual development and thyroid function of the offspring infant cortisol response after prolonged antenatal prednisolone treatment teratogen update: carcinogenesis and teratogenesis associated with exposure to diethylstilbestrol (des) in utero effects of propylthiouracil and methimazole on fetal thyroid status in mothers with graves' hyperthyroidism prolactinomas resistant to bromocriptine: long-term efficacy of quinagolide and outcome of pregnancy national institutes of health consensus development panel. antenatal corticosteroids revisited: repeat courses -national institutes of health consensus development conference statement should we continue or stop insulin sensitizing drugs during pregnancy? hypospadias in sons of women exposed to diethylstilbestrol in utero prospective parallel randomized, doubleblind, double-dummy controlled clinical trial comparing clomiphene citrate and metformin as the first-line treatment for ovulation induction in nonobese anovulatory women with polycystic ovary syndrome obstetrical outcome in 454 women exposed to diethylstilbestrol during their fetal life: a case-control analysis the long-term growth and development of children exposed to depo-provera during pregnancy and lactation birth defects after maternal exposure to corticosteroids: prospective cohort study and meta-analysis of epidemiological studies insulin lispro therapy in pregnancies complicated by type 1 diabetes mellitus early termination of pregnancy with mifepristone (ru 486) and the orally active prostaglandin misoprostol maternal thyroid hormone levels in pregnancy and the subsequent cognitive and motor performance of the children effects of in-utero exposure to oral hypoglycemic drugs development after exposure to mifepristone in early pregnancy maternal hypothyroxinaemia during early pregnancy and subsequent child development: a 3-year follow-up study first trimester exposure to corticosteroids and oral clefts fetal genital effects of firsttrimester sex hormone exposure: a meta-analysis ddavp use during pregnancy: an analysis of its safety for mother and child ovulation stimulation, assisted reproduktive techniques, and craniosynostosis pregnancy outcome after cabergoline treatment in early weeks of gestation pregnancy outcome after treatment with the ergot derivative, cabergoline malformation surveillance and maternal drug exposure: the madre project corticosteroids during pregnancy and oral defects: a case-control study impaired thyroid function in offspring of propylthiouracil treated women: a prospective controlled study on 115 pregnancies longterm outcomes of infants exposed to multiple courses of betamethasone in utero antenatal corticosteroids to prevent respiratory distress syndrome insulin lispro in pregnancy -retrospective analysis of 33 cases and matched controls the reproductive toxicity of ovulation induction effect of dexamethasone and betamethasone on fetal heart rate variability in preterm labour: a randomised study three cases of diabetes insipidus complicating pregnancy fetal malformations and failed medical termination of pregnancy pegvisomant: an advance in clinical efficacy in acromegaly. review male reproductive disorders in humans and prenatal indicators of estrogen exposure: a review of published epidemiological studies successful pregnancy in an acromegalic woman treated with octreotide congenital malformations in pregnancies complicated by niddm neural tube defects after infertility treatment: a review placental abnormalities associated with misoprostol administration (abstract) metformin reduces pregnancy complications without affecting androgen levels in pregnant polycystic ovary syndrome women: results of a randomized study oestrogen treatment to reduce the adult height of tall girls: long-term effects on fertility schwangerschaften bei hyperprolaktinämischen patientinnen aplasia cutis congenita after exposure to methimazole: a causal relationship? a comparative review of the tolerability profiles of dopamine agonists in the treatment of hyperprolactinaemia and inhibition of pregnancy dietary oestrogens and male fertility potential choanal atresia and hypothelia following methimazole exposure in utero: a second report drugs in pregnancy and delivery. report on the 13th european symposium on clinical pharmacological evaluation in drug control. copenhagen: provis edit comparison of propylthiouracil versus methimazole in the treatment of hyperthyroidism in pregnancy risk of benign gynecologic tumors in relation to prenatal diethylstilbestrol exposure congenital anomaly rate in offspring of mothers with diabetes treated with insulin lispro during pregnancy timing of vulnerability of the brain to iodine deficiency in endemic cretinism prenatal exposure to female hormones. effect of psychosexual development in boys normal pregnancy outcome following inadvertent exposure to rosiglitazone, gliclazide, and atorvastatin in a diabetic and hypertensive woman comparative maternal and neonatal effects of halothane and enflurane for cesarean section maternal awareness and neonatal outcome after ketamine induction for anesthesia for cesarean section the use of propofol, nitrous oxide or isoflurane does not affect the reproductive success rate following gamete intrafalopian transfer (gift) lidocaine toxicity after maternal pudendal anesthesia in a term infant with fetal distress effect of prenatal lignocaine on auditory brain stem evoked response surgery during pregnancy and fetal outcome neurobehavioural effects of propofol on the neonate following elective caesarean section placental transfer of succinylcholine causing transient respiratory depression in the newborn comparison of assisted reproductive technology performance after oocyte retrieval under general anaesthesia (propofol) versus paracervical local anaesthetic block. a case controlled study anaesthesia, pregnancy, and miscarriage: a study of operating room nurses and anaesthetists maternal occupational exposure and congenital malformations nitrous oxide in early human pregnancy intravenous propofol during cesarean section: placental transfer, concentrations in breast milk, and neonatal effects. a preliminary study effects of maternal anesthesia in the neonate can anesthesiologic strategies for cesarean section influence newborn jaundice? a retrospective and prospective study serum bupivacaine concentrations and transplacental transfer following repeated epidural administrations in term parturients during labour the safety of anesthesia and surgery during pregnancy reproductive and developmental toxicity of anesthetics in humans a double-blind comparison of 0,25 % ropivacaine and 0,25 % bupivacaine for extradural analgesia in labour survey of infants born in 1973 or 1975 to swedish women working in operating rooms during their pregnancy neonatal welfare and placental transfer of fentanyl and bupivacaine during ambulatory combined spinal epidural analgesia for labour maternal and fetal levels of propofol at caesarean section the hemodynamic effects of propofol and thiopentone for induction of caesarean section birth defects and drugs in pregnancy transfer of methohexital across the perfused human placenta extrapolation of the evidence on teratogenicity of chemicals between humans and experimental animals: chemicals other than drugs arthrogryposis following treatment of maternal tetanus with muscle relaxants placental propofol transfer and fetal sedaton during maternal general anaesthesia in early pregnancy arzneimittelanwendung in schwangerschaft und stillperiode long term effects of developmental halothane exposure on radial arm maze performance in rats placental transfer and neonatal effects of epidural sufentanil and fentanyl administration with bupivacaine during labor anaesthesia for caesarean delivery. part iii: general anaesthesia epidural analgesia in labor and fetal hyperthermia the use of fetal neuromuscular blockade during intrauterine procedures a comparison between propofol and thiopentone as induction agents in obstetric anesthesia effect of atracurium or pancuronium on the anemic fetus during and directly after intravascular intrauterine transfusion. a double blind randomized study outcome of pregnancy among women in anesthetic practice nitrous oxide inhalation: effects on maternal and fetal circulation at term ketamine: an update on the first twenty-five years of clinical experience developmental evaluation of children born to mothers occupationally exposed to waste anesthetic gases propofol as an induction and maintenance agent for caesarean section: maternal und neonatal effects (abstract) occupational hazards to reproduction and health in anaesthetists and peadiatricians reduced fertility among women employed as dental assistants exposed to high levels of nitrous oxide nitrous oxide and spontaneous abortion in female dental assistants comparative systemic toxicity of ropivacaine and bupivacaine in nonpregnant und pregnant ewes neurodevelopmental disability: a sibling-control study comparison of 1.5 % enflurane with 1.25 % isoflurane in oxygen for caesarean section: avoidance of awareness without nitrous oxide comparison of propofol and thiopentone for induction of anaesthesia for elective caesarean section occupational hazards of anesthesia comparison of pancuronium and vecuronium for fetal neuromuscular blockade during invasive procedures bei einer patientin wurde die therapie mit brimonidin und in beiden fällen mit timolol kombiniert da prostaglandine den uterustonus erhöhen und eine minderperfusion des fetus verursachen können, ist generell zurückhaltung geboten. falls ein schweres glaukomleiden die lokale behandlung mit prostaglandinderivaten unbedingt erfordert, sollte die dosis so niedrig wie möglich gewählt werden. einem fallbericht zufolge wurde nach mütterlicher pilocarpin-behandlung (z. b. borocarpin ® ) über die gesamte schwangerschaft ein gesundes kind geboren glaucothil ® ) sind zwar nicht systematisch untersucht, haben aber bisher keine negativen auswirkungen auf den fetus gezeigt es haben sich auch in der schwangerschaft sehr häufig verwendete präparate mit xylometazolin (z. b. olynth ® ) und oxymetazolin (z. b. nasivin ® ) bisher nicht als riskant für den fetus erwiesen, obwohl theoretisch (in hohen dosen) eine vasokonstriktion zur versorgungsstörung beim fetus führen könnte um schäden an der nasenschleimhaut zu vermeiden, sollten "entzugsstrategien" angeboten werden rhinospray ® ) liegen keine ausreichenden erfahrungen in der schwangerschaft vor latanoprost exposure in pregnancy the use of topical 5 % imiquimod during pregnancy: a case series fluticasone propionate aqueous nasal spray in pregnancy rhinitis die skabiestherapie unter besonderer berücksichtigung des frühen kindesalters, der schwangerschaft und stillzeit a retrospective study of the teratogenicity of dermatological coal tar products pregnancy outcome after periconceptional and first-trimester exposure to methoxsalen photochemotherapy teratogenic risk with etretinate and acitretine treatment is there a reproductive safety risk in male patients treated with acitretine (neotigason ® /soriatane ® )? psoralen photochemotherapy (puva) and pregnancy accutane ® -exposed pregnancies continued occurence of accutane ® exposed pregnancies teratogenicity of isotretinoin and etretinate first trimester topical tretinoin management of glaucoma in pregnancy and lactation maternal drug use in early pregnancy and infant cardiovascular defect podophyllum: suspected teratogenicity from topical application outcome of pregnancy following exposure to permethrin head lice shampoo pregnancy outcome following exposure to permethrin and use of teratogen information inadvertent 5-fluorouracil treatment in early pregnancy: a report of three cases retinoic acid embryopathy unusually high risk for adverse outcomes of pregnancy following fetal isotretinoin exposure acitretin is converted to etretinate only during concomitant alcohol intake prenatal and early postnatal intoxication by inorganic mercury resulting from maternal use of mercury containing soap the use of acetazolamide in idiopathic intracranial hypertension during pregnancy multiple congenital defects associated with maternal use of topical tretinoin minor malformations characteristic of the retinoic acid embryopathy and other birth outcomes in children of women exposed to topical tretinoin during early pregnancy first-trimester exposure to topical tretinoin: its safety is not warranted [letter treatment of external genital warts with 5 % imiquiod cream during pregnancy: a case report safety of the insect repelent n,n,-diethyl-m-toluamide (deet) in pregnancy pharmacokinetics and safety of tazaroten temporal bone pathology in fetuses exposed to isotretinoin risk of intrauterine growth retardation, malformations and other birth outcomes in children after topical use of corticosteroid in pregnancy multiple congenital malformations associated with topical tretinoin steady-state pharmacokinetics of isotretinoin and its 4-oxo metabolite: implications for fetal safety 5-fluorouracil exposure during the period of conception: a report of two cases transient renal tubular acidosis in a neonate following transplacental acetazolamide kopfläuse -umgang mit einer wieder auflebenden parasitose topical medications during pregnancy mental retardation and parental occupation: a study on the applicability of job exposure matrices extreme caudal agenesis intrauterine diethyltoluamide exposure and fetal outcome otocerebral anomalies associated with topical tretinoin use safety of topical minoxidil solution: a one-year, prospective, observational study safety of first-trimester exposure to topical tretinoin: prospective cohort study topically applied minoxidil may cause fetal malformation: a case report deet: a review and update of safety and risk in the general population plasma absorption and ultrastructural changes of rat testicular cells induced by lindane recommendations for isotretinoin use in women of childbearing potential transdermal absorption of topical anti-acne agents in man; review of clinical pharmacokinetic data neonatal transient hypothyroidism: aetiological study. italian collaborative study on transient hypothyroisism wissenschaftlicher beirat der bundesärztekammer. zur anwendung von polyvinylpyrrolidon-jod-komplexen (povidonjod: pvp-jod) bei ausgewogener und vielseitiger ernährung ist eine zusätzliche substitution von vitaminen oder mineralien nicht routinemäßig erforderlich, mit ausnahme von folsäure in der frühschwangerschaft und iodid. es wird kontrovers diskutiert, ob eine substitution weitere vitamine das risiko von fehlbildungen senkt combined chemotherapy and radiotherapy during conception and first two trimesters of gestation in a woman with metastatic breast cancer the safety of higher than standard dose of doxylamine-pyridoxine for nausea and vomiting of pregnancy folic acid supplementation and the occurrence of congenital heart defects, orofacial clefts, multiple births, and miscarriage bundesinstitut für gesundheitlichen verbraucherschutz und veterinärmedizin). versorgung der deutschen bevölkerung mit folsäure noch immer ungenügend bedeutung von vitamin a für die lungenentwicklung high doses of vitamin e and pregnancy outcome pregnancy outcome following high doses of vitamin e supplementation; a prospective controlled study vitamin a and cardiac outflow tract defects do multivitamin or folic acid supplements reduce the risk for congenital heart defects? evidence and gaps dietary folate as a risk factor for neural-tube defects: evidence from a case-control study in western australia treatment of wilson's disease with zinc. xvii: treatment during pregnancy comparison of three outpatient regimens in the management of nausea and vomiting in pregnancy teratogenität von retinoiden (isotretinoin, etretinat) und vitamin a the teratogenic metabolites of vitamin a in women following supplements and liver vitmin c supplementation to prevent premature rupture of the chorioamniotic maternal and fetal plasma levels of pyridoxal phosphate at term: adequacy of vitamin b 6 supplementation during pregnancy elevated plasma homocysteine in early pregnancy: a risk factor for the development of severe preeclampsia effect of increasing dietary folate on red-cell folate: implications for prevention of neural tube defects prevention of the first occurrence of neural-tube defects by periconceptional vitamin supplementation hungarian cohort-controled trial of periconceptional multivitamin supplementation shows a reduction in certain congenital abnormalities use of 6,000 iu vitamin a during early pregnancy without teratogenic effect fish oil supplementation in pregnancy modifies neonatal allergen-specific immune responses and clinical outcomes in infants at high risk of atopy: a randomized controlled trial human plasma all-trans-, 13-cis and 13-cis oxoretinoic acid profiles during subchronic vitamin a supplementation prävention von neuralrohrdefekten. weiterhin nur geringe akzeptanz der empfehlungen zur folsäureprophylaxe folic acid supplements during pregnancy and the risk of miscarriage low maternal dietary intake of iron, magnesium, and niacin are associated with spina bifida in the offspring osteoporose und mehrlingsgraviditätein erfahrungsbericht mit positivem ausgang riboflavin status in pregnancy impact of folic acid fortification of the us food supply on the occurrence of neural tube defects folic acid metabolism and human embryopathy maternal vitamin d status during pregnancy and childhood bone mass at age 9 years: a longitudinal study use of folic acid and delivery outcome: a prospective registry study folic acid and human malformation: a summary and evaluation maternal nutritional status and the risk for orofascial cleft in humans empfehlungen zur gabe von vitamin a in der schwangerschaft double-blind randomised controlled trial of folate treatment before conception to prevent recurrence of neuraltube defects anaemia and haematinics in pregnancy fetal outcome after intrauterine exposure to biphosphonates preventing neural tube defects with periconceptional folic acid supplementation: a population-based intervention program in the people's republic of china vitamin passage across the placenta biotin plasma levels of the human fetus high vitamin a intake in early pregnancy and major malformations: a multicenter prospective controlled study accelerated folate-breakdown in pregnancy medical research council (mrc) vitamin study research group. prevention of neural tube defects: results of the mrc vitamin study neural tube defect rates before and after food fortification with folic acid retinoic acid receptor alpha gene variants, multivitamin use, and liver intake as risk factors for oral clefts: a population-based case-control stud in denmark periconceptional use of multi-vitamins and the occurrence of neural tube defects folic acid supplementation and risk for imperforate anus in china hyperhomocysteinaemia and recurrent early pregnancy loss: a meta-analysis homocysteine and folate levels as risk factors for recurrent early pregnancy loss empfehlungen der-: perikonzeptionelle folsäuresubstitution. richtlinien zur prävention von neuralrohrdefekten randomised clinical trials of fish oil supplementation in high risk pregnancies the transplacental effects of alendronate on the fetal skeleton in rats folic acid fortification: a populationbased study of its effect on the incidence of open neural tube defects (ontds) zur biokinetik von mikronährstoffen und deren interaktionen. dialog ernährung und vitamins and minerals in pregnancy clinical teratology counseling and consultation report: high-dose g -carotene use during early pregnancy low vitamin b12 level as a risk factor for early recurrent abortion vitamin a congeners folic acid and neural-tube defects -time for action? teratogenicity of high vitamin a intake royal college of general practitioners. morbidity and drugs in pregnancy no effects of biphosphonates on the human fetus women and omega-3 fatty acids plasma folate, vitamine b12, and homocyst(e)ine concentrations in preeclamptic and normotensive peruvian women is dietary intake of methionine associated with a reduction in risk for neural tube defect-affected pregnancies? periconceptional intake of vitamin supplements and risk of multiple congenital anomalies letter to the editor: intravenous iron polymaltose comlex for treatment of iron deficiency anaemia in pregnancy resistant to oral iron therapy possible prevention of neutraltube defects by periconceptional vitamin supplementation collagen synthesis during pregnancy, vitamin c availability, and risk of premature rupture of fetal membranes summary of the 1993 teratology society public affairs committee symposium: folic acid prevention of neural tube defects-public policy issues position paper: recommendations for vitamin a use during pregnancy primary prevention of neural tube defects with folic acid supplementation: cuban experience riboflavin deficiency and preeclampsia quantifying the effect of folic acid safety of vitamin a: recent results marginal biotin deficiency is teratogenic maternal plasma ascorbic acid (vitamin c) and risk of gestational diabetes mellitus vitamin c and the risk of gestational diabetes mellitus: a case-control study empfehlung für die praxis: pflanzentees und anderen zubereitungen mit ungeklärter herkunft, bei denen pyrrolizidinalkaloide enthalten sein könnten, sollten in der schwangerschaft strikt gemieden werden letter to the editor: ginger in preventing nausea and vomiting of pregnancy; a caveat due to its thromboxane synthetase activity and effect on testosterone binding ist ingwer ein klinisch relevantes antiemetikum? eine systematische übersicht randomisierter kontrollierter studien drugs in pregnancy and lactation effect of viscum album l. on rapidly proliferating amniotic fluid cells. sister chromatid exchange frequency and proliferation index multiple follicular development associated with herbal medicine schmerzbehandlung mit pflanzlichen antirheumatika oral evening primrose oil: its effect of length of pregnancy and selected intrapartum outcomes in low-risk nulliparous women herbal medicinal products during pregnancy: are they safe seroius adverse effects of unconventional therapies for children and adolescents: a systematic review of recent evidence ginger treatment of hyperemesis gravidarum can herbal products be used safely during pregnancy? focus on echinacea homöopathie und schulmedizin in der schwangerschafts-und geburtsbetreuung re: preterm birth and licorice consumption during pregnancy weisen teedrogen der traditionellen chinesischen medizin qualitätsmängel auf? surveillance study of sinupret in comparison with data of the mainz birth registry potenzial toxicities of herbal therapies in the developing fetus ginger syrup as an antiemetic in early pregnancy cinnamon improves glucose and lipids of people with type 2 diabetes are herbal medicinal products less teratogenic than western pharmaceutical products? reproductive toxicicity studies of d-camphor in rats and rabbits use of herbal drugs in pregnancy: a survey among 400 norwegian women prospective comparitive study of the safety and effectiveness of ginger for the treatment of nausea and vomiting in pregnancy camphor ingestion for abortion (case report) veno-occlusive disease in a fetus caused by pyrrolizidine alkaloids of food origin uterotonic action of extracts from a group of medicinal plants a randomized controlled trial of ginger to treat nausea and vomiting in pregnancy homeopathy for induction of labour preterm birth and licorice consumption during pregnancy birth outcome in relation to licorice consumption during pregnancy severe congenital lead poisoning in a preterm infant due to a herbal remedy an evaluation of echinacea angustifolia in experimental rhinovirus infections ginger for nausea and vomiting in pregnancy: randomized double-masked, placebo-controlled trial investigation of the teratogenic potential of a zingiber officinale extract in the rat wissenschaftliche verlagsgesellschaft mbh stuttgart effect of ginger tea on the fetal development of sprague-dawley rats effect of ginger extract on pregnancy-induced nausea: a randomized controlled trial john's wort (hypericum perforatum) administered radionuclides in pregnancy a three-year follow-up of children imaged in utero with echo-planar magnetic resonance high-dose radioiodine treatment for differentiated thyroid carcinoma is not associated with change in female fertility or any genetic risk to the offspring diagnostic imaging committee, society of obstetricians and gynaecologists of canada. obstetric ultrasound biological effects and safety childhood and adult cancer after intrauterine exposure to ionizing radiation utilization of developmental basic science principles in the evaluation of reproductive risks from pre-and postconception environmental radiation exposures reproductive and teratologic effects of low-frequency electromagnetic fields: a review of in vivo and in vitro studies using animal models reproductive and teratogenic effects of electromagnetic fields pregnancy outcome after diagnosis of differentiated thyroid carcinoma: no deleterious effect after radioactive iodine treatment teratogen update: methylene blue dye use during amniocentesis and birth defects a review of the current use of magnetic resonance imaging in pregnancy and safety implications for the fetus deutsche gesellschaft für medizinische physik und deutsche röntgengesellschaft. pränatale strahlenexposition aus medizinischer indikation. dosisermittlung, folgerungen für arzt und schwangere infertility and pregnancy outcome among magnetic resonance imaging workers safety of indocyanine green angiography during pregnancy: a survey of the retina, macula, and vitreous societies methylene blue-induced hyperbilirubinemia in neonatal glucose-6-phosphate dehydrogenase (g6pd) deficiency safety of fluorescein angiography during pregnancy prenatal x-ray exposure and childhood cancer in twins antepartum dental radiography and infant low birth weight intrauterine effects of ultrasound: animal studies absence of harmful effects of magnetic resonance exposure at 1.5 t in utero during the third trimester of pregnancy: a follow-up study antepartum dental radiography and low birth weight normal placenta: gadoliniumenhanced, dynamic mr imaging changing perspectives on the genetic doubling dose of ionizing radiation for humans, mice, and drosophila effects of repeated prenatal ultrasound examinations on childhood outcome up to 8 years of age: follow-up of a randomised controlled trial effects of frequent ultrasound during pregnancy: a randomized controlled trial parental exposure to medical radiation and neuroblastoma in offspring a 36-year retrospective analysis of the efficacy and safety of radioactive iodine in treating young graves' patients intrauterine effects of electromagnetic fields-(low frequency, mid frequency rf, and microwave): review of epidemiologic studies exposure to radioactive iodine-131 for scintigraphy or therapy does not preclude pregnancy in thyroid cancer patients embryotoxicity of stable isotopes and use of stable isotopes in studies of teratogenic mechanisms radiation risk in pregnancy effects of frequent ultrasound during pregnancy risk coefficients for childhood cancer after intrauterine irradiation: a review members of contrast media safety committee of european society of urogenital radiology (esur). the use of iodinated and gadolinium contrast media during pregnancy and lactation fetal thyrotrophin: the best indicator of long term thyroid function after in utero exposure to iodine-131 intrauterine effects of ultrasound: human epidemiology sudden infant death syndrome and prenatal maternal smoking: rising attributed risk in the back to sleep era methadone maintenance in a swiss perinatal center: ii. neonatal outcome and social resources fetal alcohol spectrum disorders in finland: clinical delineation of 77 older children and adolescents prenatal exposure to binge drinking and cognitive and behavioral outcomes at age 7 years longitudinal influence of prenatal cocaine exposure on child language functioning severity of prenatal cocaine exposure and child language functioning through age seven years: a longitudinal latent growth curve analysis caffeine use during pregnancy and child outcome: a 7-year prospective study prenatal cocaine exposure and children's language functioning at 6 and 9.5 years: moderating effects of child age, birthweight, and gender effects of caffeine consumption on pregnancy outcome: a review maternal methadone dose and neonatal withdrawal maternal smoking during pregnancy and offspring iq parental cigarette smoking and the risk of acute leukemia in children maternal smoking during pregnancy and risk of brain tumors in offspring review of the epidemiological evidence relating toluene to reproductive outcomes effects of caffeine on development and behavior in infancy and childhood: a review of the published literature amphetamine addiction during pregnancy: 14 year follow-up of growth and school performance smoking during pregnancy: a significant cause of neonatal thyroid enlargement maternal cocaine use and genitourinary tract malformations maternal smoking during pregnancy in relation to child overweight: follow-up to age 8 years teratogen update: evaluation of the reproductive and developmental risks of caffeine maternal cigarette smoking during pregnancy and the risk of having a child with cleft lip/palate behavioral development in children prenatally exposed to drugs and alcohol prenatal tabacco effects on neuropsychological outcomes among preadolescents prenatal alcohol exposure predicts continued deficits in offspring size at 14 years of age maternal smoking during pregnancy is associated with a higher risk of non-syndromic orofacial clefts in infants maternal cannabis use and birth weight: a meta-analysis european concerned action: maternal alcohol consumption and its relation to the outcome of pregnancy and child development at 18 months birth outcome from a prospective, matched study of prenatal crack/cocaine use: i. interactive and dose effects on health and growth birth outcome from a prospective, matched study of prenatal crack/cocaine use: ii. interactive and dose effects on neurobehavioral assessment prenatal cocaine exposure prospective pregnancy outcome in women exposed to amphetamines maternal smoking before and after pregnancy: effect on behavioral outcomes in middle childhood moderate to heavy caffeine consumption during pregnancy and relationship to spontaneous abortion and abnormal fetal growth: a meta-analysis growth, development, and behavior in early childhood following prenatal cocaine exposure: a systematic review growth and pubertal milestones during adolescence in offspring prenatally exposed to cigarettes and marihuana a literature review of the consequences of prenatal marihuana exposure. an emerging theme of a deficiency in aspects of executive function growth from birth to early adolescence in offspring prenatally exposed to cigarettes and marijuana 36-and 48-month neurobehavioral follow-up of children prenatally exposed to marijuana, cigarettes and alcohol. develop behavioral prenatal marijuana and alcohol exposure and academic achievement at age 10 ntp-cerhr expert panel report on the reproductive and developmental toxicity of amphetamine and methamphetamine passive smoking and pregnancy outcome in central poland further evidence for an association between -maternal smoking and craniosyostosis prenatal cocaine exposure and fetal vascular disruption methadone maintenance vs. implantable naltrexone treatment in the pregnant heroin user a randomised controlled trial of morphine versus phenobarbitone for neonatal abstinence syndrome drinking moderately and pregnancy. effects on child development use of buprenorphine in pregnancy: patient management and effects on the neonate inhalant abuse in pregnancy recognition of the fetal alcohol syndrome in early infancy maternal smoking and craniosynostosis maternal smoking during pregnancy and limb reduction malformations in sweden buprenorphine withdrawal syndrome in newborns: a report of 13 cases multicenter allergy study group, germany. the association between pre-and postnatal tobacco smoke exposure and allergic sensitization during early childhood parental smoking and neonatal serum levels of polychlorinated biphenyls and hexachlorobenzene tabakspezifische transplazentare kanzerogene, nikotin und cotinin im urin von neugeborenen rauchender mütter a review of the literature relating coffeine consumption by women to their risks of reproductive hazards maternal smoking during pregnancy and the risk of congenital urinary tract anomalies smoking during pregnancy and the risk for hyperkinetic disorder in offspring united kingdom-based case-control study. smoking and orofacial clefts: a united kingdom-based case-control study tobacco smoking and oral clefts: a meta-analysis failure to recognize fetal alcohol syndrome in newborn infants is there a cocaine syndrome? dysmorphic and anthropometric assessment of infants exposed to cocaine zur frage der interruption bei alkoholkranken frauen prenatal exposure to salicylates and gastroschisis: a case-control study congenital anomalies after prenatal ecstasy exposure cocaine, pregnancy and postpartum intracerebral hemorrhage the maternal lifestyle study: cognitive, motor and behavioral outcomes of cocaine-exposed and opiate-exposed infants through three years of age transplacental transfer and metabolism of buprenorphine maternal passive smoking during pregnancy and fetal developmental toxicology. part 1: gross morphological effects maternal passive smoking during pregnancy and fetal developmental toxicology. part 2: histological changes cotinine in meconium indicates risk for early respiratory tract infections binge alcohol consumption by non-alcohol dependent women during pregnancy affects child behavior, but not general intellectual functioning; a prospective controlled study smoking during pregnancy and babbling abilities of the 8-month-old infant association of prenatal alcohol exposure with behavioral and learning problems in early adolescence developmental outcome of schoolage children born to mothers with heroin dependency: importance of environmental factors effect of paternal alcohol consumption before conception on infant birth weight moderate alcohol consumption during pregnnancy and the incidence of fetal malformations: a meta-analysis prenatal cocaine exposure: effects on the development of school-age children opiate addiction in gravidity -consequences for the newborn. results of an interdisciplinary treatment concept candidate genes for nonsyndromic cleft lip and palate and maternal cigarette smoking and alcohol consumption: evaluation of genotype-environment interactions from a population-based case-control study of orofacial clefts from in utero and childhood exposure to parental smoking to childhood cancer: a possible link and the need for action. human & experimental kokain in der schwangerschaft: ein zweites contergan? chemically induced birth defects follow-up of infants prenatally exposed to cocaine neonatal outcome following buprenorphine maintenance during conception and throughout pregnancy alkoholkonsum und intrauterine dystrophie maternal smoking and infantile gastrointestinal dysregulation: the case of colic methadone dosage for prevention of opioid withdrawal in children maternal coffeine consumption and spontaneous abortion: a review of the epidemiologic evidence talipes equinovarus and maternal smoking: a population-based case-control study in washington state effects of prenatal methamphetamine exposure on fetal growth and drug withdrawal symptoms in infants born at term teratogene effekte von nikotin prenatal alcohol exposure and long-term developmental consequences the fetal alcohol syndrome in adolescence die berliner verlaufsstudie von kindern mit einem fetalem alkoholsyndrom (fas). 1. pädiatrische befunde longterm outcome of children with fetal alcohol syndrome: psychopathology, behavior and intelligence correlates of psychopathology and intelligence in children with fetal alcohol syndrome die berliner verlaufsstudie von kindern mit einem fetalem alkoholsyndrom (fas). 2. psychiatrische und psychologische befunde fetal alcohol syndrome in adolescents and adults maternal drinking during pregnancy: attention and short term memory in 14-year old offspring: a longitudinal prospective study a dose-response-study of the enduring effects of prenatal alcohol exposure: birth to 14 years laboratory work and pregnancy outcome high caffeine consumption in the third trimester of pregnancy: gender-specific effects on fetal growth what happens to babies exposed to phencyclidine (pcp) in utero? parental cigarette smoking and risk for congenital anomalies of the heart, neural tube, or limb teratogen update: smoking and reproductive outcomes teratogen update: toluene maternal consumption of coffee during pregnancy and stillbirth and infant death in first year of life: prospective study maternal and transplacental effects of cocaine oral clefts, maternal smoking, and tgfa: a meta-analysis of gene-environment interaction eine epidemiologische studie aus ungarn untersucht den schwangerschaftsverlauf von 109 frauen, die wegen akuter vergiftungen während verschiedener phasen der schwangerschaft im krankenhaus behandelt wurden aflatoxine und cytochalasin b und d, gibt es bisher keine sicheren anhaltspunkte dafür, dass diese giftstoffe auch beim menschen fehlbildungen hervorrufen (übersicht in schardein ) lässt erahnen, dass ggf. auch pflanzliche gesundheitsprodukte kritisch beobachtet werden müssen. dafür spricht auch eine publikation über leberschäden bei einem neugeborenen, dessen mutter große mengen pflanzentees zu sich genommen hatte, die pyrrolizidinalkaloide enthielten wie langwierig die klärung hypothetischer assoziationen zwischen fehlbildungen und giften in nahrung oder heilmitteln pflanzlicher herkunft sein kann, wird an dem von renwick (1972) vermuteten zusammenhang zwischen neuralrohrdefekten (exenzephalie, spina bifida) und dem verzehr von bräunlich verfärbten kartoffeln deutlich. es dauerte fast ein jahrzehnt, bis zweifelsfrei gezeigt werden konnte, dass die genannten fehlbildungen nicht folge des verzehrs von (verdorbenen) kartoffeln waren diphtherie) gibt es berichte über spezielle embryotoxische auswirkungen nach erkrankung der mutter in der schwangerschaft aspirin overdose in mother and fetus carbon monoxide poisoning in pregnancy are there teratogenic risks associated with antidotes used in the acute management of poisoned pregnant women reproductive hazards of industrial chemicals amatoxins do not cross the placental-barrier methanol toxicity in a newborn fatal colchicine poisoning. two particular cases. (abstract) multiple organ failure with the adult respiratory distress syndrome in homicidal arsenic poisoning intoxication by benzodiazepines during pregnancy toxic effect of podophylline application in pregnancy a study of adverse effects on the progeny after intoxication during pregnancy teratologic evaluation of 178 infants born to mothers who attempted suicide by drugs during pregnancy morsures de serpents au cours de la grossesse arsenic ingestion in pregnancy acute iron poisoning: its effects and treatment pregnancy outcome after suicide attempt by drug use: a danish population-based study haloperidol overdose during pregnancy methanol poisoning during late pregnancy kctg-verlaufsbeobachtung nach diazepam-intoxikation thallium poisoning during pregnancy: a case report and comprehensive literature review placental transfer of n-acetylcysteine following human maternal acetaminophen toxicity snake bite in pregnancy mother and fetus both survive from severe paraquat intoxication organophosphate poisoning in pregnancy: a case report arsenic encephalopathy in pregnancy with recovery podophyllum: suspected teratogenicity from topical application fetal damage due to mushroom poisoning with amanita phalloides during the first trimester of pregnancy deferoxamine treatment for acute iron intoxication in pregnancy fetal compromise caused by maternal carbon monoxide poisoning maternal ginseng use associated with neonatal androgenization a multicenter, prospective study of fetal outcome following accidental carbon monoxide poisoning in pregnancy acute iron intoxication in pregnancy: case report and review of the literature a review of venomous animal bites and stings in pregnant patients exposure to non-steroidal anti-inflammatory drugs during pregnancy and risk of miscarriage: population-based cohort study drug overdoses during pregnancy acute maternal arsenic intoxication with neonatal death über einen fall von kohlenoxydgasschädigung des kindes in der gebärmutter the outcome of pregnancy following iron overdose by the mother drugs during pregnancy and lactation the consequences of iron overdose and its treatment with desferrioxamine in pregnancy outcome of pregnancy following deliberate iron overdose by the mother paracetamol overdose in pregnancy: analysis of the outcomes of 300 cases referred to the teratology information service podophyllin poisoning associated with the treatment of condyloma accuminatum. a case report intrauterine fetal death caused by pit viper venom poisoning in early pregnancy risk of adverse birth outcome and miscarriage in pregnant users of non-steroidal anti-inflammatory drugs: population based observational study and case-control study fatal iron intoxication in late pregnancy aspirin poising during pregnancy: increased fetal sensitivity management of snake and spider bite in pregnancy neonatal bromide intoxication: prenatal ingestion of a large quantity of bromides with transplacental accumulation in the fetus botulism and pregnancy spina bifida, anencephaly, and potato blight botulism in a pregnant woman favourable neonatal outcome following maternal paracetamol overdose and severe fetal distress. case report hepatic veno-occlusive disease in newborn infant of a woman drinking herbal tea mega-dose carbamazepine complicating third trimester of pregnancy chemically induced birth defects amanita poisoning during pregnancy mort néonatale par malformations multiplesà la suite de l'action du poison d'abeilles snakebite during pregnancy organophosphate poisoning associated with fetal death: a case study transplacental neonatal digitalis intoxication hyperbaric oxygen teatment during pregnancy in acute carbon monoxide poisoning podophllin poisoning: systemic toxicity following cutaneous application observations of an infant born to a mother with botulism delirium induced by topical application of podophyllin: a case report paraquat intoxication during pregnancy: a report of 9 cases poisoning in pregnancy. maternal & fetal toxicology 2nd edition s. 223-252 methanol poisoning during pregnancy -prediction of risk and suggestions for management birth weight and congenital anomalies following poisonous mushroom intoxication during pregnancy intentional iron overdose in pregnancymanagement and outcome acute intentional iron overdose in pregnancy experience with acute paraquat poisoning in crete successful therapy of iron intoxication in pregnancy with intravenous deferoxamine and whole bowel irrigation inhalational methanol toxicity in pregnancy treated twice with fomepizole foetal and neonatal exposure to aflatoxins fatal systemic poisoning following podophylline treatment of condyloma accuminatum maternal water intoxication as a cause of neonatal seizures leichten fällen nur durch mäßig ausgeprägte mentale retardierung auffiel, kamen bei manchen kindern noch herz-, skelett-, augen-und ohrfehlbildungen hinzu in der europäischen eurohazcon-studie war das risiko bei frauen, ein fehlgebildetes kind zur welt zu bringen, erhöht, wenn sie im umkreis von 3 km zu einer giftmülldeponie wohnten. außerdem gab es hinweise auf vermehrtes auftreten chromosomaler störungen (vrijheid deutsche forschungsgemeinschaft, jährliche aktualisierung) für chemische arbeitsstoffe bzw. industriechemikalien aufgenommen. mit zustimmung des bundesarbeitsministers von der dfg herausgegeben hat die liste nicht nur arbeitsrechtliche konsequenzen für betroffene frauen und für die berufsgenossenschaften, sondern sie ist bis heute die einzige "amtliche" grundlage für die ärztliche beratung von schwangeren, die am arbeitsplatz oder auch außerhalb ihrer arbeit mit industrie-und umweltchemikalien in kontakt kommen. in tabelle 2.5 sind die stoffe aufgelistet, die die mak-werte-kommission hinsichtlich ihrer fruchtschädigenden eigenschaften verschiedenen risikogruppen zugeordnet hat zu den auswirkungen von mobiltelefonnutzung und den digitalen mobiltelefonsendern in wohnraumnähe gibt es bisher keine aussagefähigen studien zu potenziellen auswirkungen auf eine schwangerschaft. nach einem stromschlag während der schwangerschaft sollte das fetale befinden per ultraschall kontrolliert werden. andere regelmäßige applikationen von erheblichen elektromagnetischen feldern sollten vermieden werden chernobyl fallout and outcome of pregnancy in finland environmental exposure to lead and childrens intelligence at the age of seven years reproductive hazards of industrial chemicals a preliminary assessment of the consequences for inhabitants of the uk of the chernobyl accident während der schwangerschaft verzehr bestimmter fischarten einschränken organochlorines and heavy metals in pregnant women from the disko bay area in greenland risk of selected borth defects by maternal residence close to power lines during pregnancy chernobyl, childhood cancer, and chromosome 21 effect of magnetic field emitted by cellular phones on fetal heart rate maternal residental proximity to hazardous waste sites and risk for selected congenital malformations an assessment of the developmental toxicity of inorganic arsenic health status at birth of inuit newborns prenatally exposed to organochlorines risk of congenital anomalies near hazardous-waste landfill sites in europe: the eurohazcon study pesticide exposure and birth weight: an epidemiological study in central poland fetal death and congenital malformation in babies born to nuclear industry employees: report from the nuclear industry family study spontaneous abortion in dry cleaning workers potentially exposed to perchloroethylene maternal blood lead effects on infant intelligence at age 7 months accidental electrical shock in pregnancy: a prospective cohort study european food safety authority (efsa). risikobewertung für quecksilber in fisch für besonders gefährdete bevölkerungsgruppen hydroxylated pcb metabolites and pcbs in serum from pregnant faroese women general, reproductive, developmental, and endocrine toxicity of boronated compounds follow up study of children born to mothers resident in seascale, west cumbria persistent organochlorine compounds and birth weight cognitive deficit in 7-year-old children with prenatal exposure to methylmercury animal testing and alternative approaches for the human health risk assessment under the proposed new european chemicals regulation teratogen update: polychlorinated biphenyls intellectual impairment in children exposed to polychlorinated biphenyls in utero inhalant abuse in pregnancy relationships of maternal blood lead and disorders of pregnancy to neonatal birthweight drinking water chlorination and delivery outcome -a registry-based study in sweden effects of dioxins and polychlorinated biphenyls on thyroid hormone status of pregnant women and their infants spontaneous abortions and congenital malformations among women exposed to tetrachlorethylene in dry cleaning effect of polychlorinated biphenyls on psychodevelopment parental smoking and neonatal serum levels of polychlorinated biphenyls and hexachlorobenzene exposure to organic solvents during pregnancy and oral clefts: as case control study maternal and neonatal hair mercury concentrations: the effect of dental amalgam paternal organic solvent exposure and adverse pregnancy ourtcomes: a meta-analysis preganancy outcome following maternal organic solvent exposure: a meta-analysis of epidemiologic studies intellectual function of children exposed to polychlorinated biphenyls in utero the oestrogenic potential of the phthalate esters prenatal methyl mercury exposure from ocean fish consumption in the seychelles child development study chlorination disinfection by products in water and their association with adverse reproductive outcomes: a review stillbirths among offspring of male radiation workers at sellafield nuclear processing plant effects of environmental exposure to polychlorinated biphenyls and dioxins on cognitive abilities in dutch children at 42 months of age the effect of ambient carbon monoxide on low birth weight among children in southern california between 1989 and 1993. environ health perspect 1999 intrauterine effects of electromagnetic fields-(low frequency, mid frequency rf, and microwave): review of epidemiologic studies sex ratio after exposure to dioxinlike chemicals in taiwan chemically induced birth defects untersuchungen zur quecksilberbelastung fetaler und frühkindlicher organe infolge mütterlicher exposition durch zahnamalgam maternal periconceptional use of electric bed-heating devices and risk for neural tube defects and orofacial clefts maternal occupational exposure to organic solvents during pregnancy and subsequent cognitive and visual functioning in the child: a prospective controlled study women in dental surgeries: reproductive hazards in environmental exposure to metallic mercury significant increase in trisomy 21 in berlin nine months after the chernobyl reactor accident: temporal correlation or causal relation? bewertung des embryotoxischen risikos von industriechemikalien in der schwangerschaft review of recent vietnamese studies on the carcinogenic and teratogenic effects of phenoxy herbicide exposure prenatal pcb exposure and neonatal behavioral assessment scale (nbas) performance cognitive development of preschool children prenatally exposed to pcbs and mehg maternal seafood diet, methylmercury exposure and neonatal neurologic function male reproductive disorders in humans and prenatal indicators of estrogen exposure. a review of published epidemiological studies lifetime exposure to environmental lead and children's intelligence at 11-13 years -the port pirie cohort study blitzschlag -tödliche schädigung des fetus in der spätschwangerschaft chromosomal congenital anomalies and residence near hazardous waste landfill sites lead exposure and motor functioning in 4 1/2-year-old children: the yugoslavia prospective study teratogen update: toluene effects of low-level lead exposure in utero menstrual disorders among drycleaning workers eine substitution ist selten indiziert, z. b. bei addison-krankheit. die erforderlichen dosen an glucocorticoiden und mineralocorticoiden helfen, wieder physiologische verhältnisse zu erreichen, und haben weder für die mutter noch für den exponierten fetus nebenwirkungen. eine langzeitbehandlung mit hohen therapeutischen dosen bei allergischen, entzündlichen oder proliferativen erkrankungen führt zu gravie-andere augen-, nasen-und ohren-präparate glucocorticoide, cromoglicinsäure, antihistaminika, antibiotika und aciclovir sowie filmbildner ("künstliche tränenflüssigkeit"), wie z. b. povidon (z. b. arufil ® ), dürfen indikationsgerecht angewendet werden. aus grundsätzlichen erwägungen sollte auf chloramphenicol verzichtet werden.die nasale oder inhalative anwendung von budesonid und anderer corticosteroide hat keine nennenwerte teratogenität gezeigt (källén 2003) .bei 26 frauen, die im rahmen einer randomisierten doppelblindstudie fluticason-nasenspray benutzten, fand sich gegenüber der placebogruppe kein unterschied in der entwicklung der neugeborenen (ellegard 2001) .zu dem neueren ophthalmologikum loteprednol (lotemax ® ) gibt es bisher keine erfahrungen zur anwendung in der schwangerschaft. es ist ähnlich zu bewerten wie andere lokale glucocorticoide und für eine kurzzeitanwendung akzeptabel, wenn keine anderen therapiemöglichkeiten zur verfügung stehen. g 2.17.18 hämorrhoidenmittel pharmakologie und toxikologie. hämorrhoidenmittel (hämorrhoidensalben und suppositorien) sind lokaltherapeutika, die als einzelstoffe oder in kombination meistens lokalanästhetika, glucocorticoide, antibiotika und desinfizienzien enthalten. diese präparate werden auch zur nachbehandlung operativer eingriffe im rekto-analen bereich eingesetzt.empfehlung für die praxis: die üblichen hämorrhoidenmittel haben sich in der schwangerschaft als unbedenklich erwiesen. g 2.17.19 venentherapeutika aescin-präparate (rosskastanienextrakt) bei venenbeschwerden sind in der schwangerschaft bisher nicht als problematisch aufgefallen, aber nicht systematisch untersucht.eine venenverödung bei krampfadern, z. b. mit polidocanol (macrogollaurylether; z. b. aethoxysklerol ® ), darf -falls zwingend erforderlich -auch während der schwangerschaft durchgeführt werden.da ausreichende erfahrungen auch für die lokale anwendung von minoxidil in der schwangerschaft nicht vorliegen, sollte auf eine längerfristige anwendung verzichtet werden.gleiches gilt für eflornithin (vaniqa ® ), das zur äußerlichen behandlung des hirsutismus angeboten wird. g 2.17.22 kosmetika kosmetika, auch haarkosmetika einschließlich färben und dauerwelle, dürfen, wenn es die befindlichkeit der schwangeren fördert, im üblichen rahmen angewendet werden. adams j, lammer e. relationship between dysmorphology and neuropsychological functions in children exposed to isotretinoin (in utero). in: fujii t, boer gj (ed (hubbard 1965) . 1980 ließen erste studien vermuten, dass sich diese schwerwiegenden angeborenen fehlbildungen durch gabe von multivitaminpräparaten (smithells 1980) bzw. folsäure (laurence 1981) verhindern lassen. umfangreiche untersuchungen in den usa (mulinare 1988) , australien (bower 1989) , kuba (vergel 1990 ), england (medical research council 1991 und ungarn bestätigten eine protektive wirkung der folsäuresubstitution. in der ungarischen studie lag die häufigkeit von neuralrohrdefekten bei kindern von frauen, die vor und während der schwangerschaft ein multivitaminpräparat eingenommen hatten, das eine tägliche dosis von 0,8 mg folsäure enthielt, um 50 % bzw. 90 % ) niedriger als in der kontrollgruppe, die nur spurenelemente eingenommen hatte g 2.20.7 ultraschall-und magnetresonanz-kontrastmittel pharmakologie und toxikologie. als kontrastmittel wird bei der ultraschalldiagnostik d-galaktose (echovist-200 ® , echovist-300 ® ) eingesetzt, von dem kein pränatal toxisches risiko zu erwarten ist.gadopentetsäure (magnevist ® ), gadobensäure (multihance ® ), gadodiamid (omniscan ® ), gadoteridol (prohance ® ), gadotersäure (dotarem ® ) und gadoxetsäure (primovist ® ) sind ionische, paramagnetische kontrastmittel, die bei der magnetresonanzdarstellung (mrt) benutzt werden. soweit untersucht, ergaben tierversuche keine hin-arnd) und die als alcohol related birth defects (arbd) bezeichneten fehlbildungen.das fetale schädigungsmuster hängt von der zeitlichen intensität des mütterlichen alkoholkonsums in der schwangerschaft ab. so führt ein intensiver alkoholmissbrauch in der frühschwangerschaft eher zu den typischen kraniofazialen dysmorphien und organschädigungen, während heftiges trinken in der späteren fetalen phase der schwangerschaft zu einer ausgeprägten neuronalen schädigung des rasch wachsenden gehirns mit der folge psychomentaler und kognitiver störungen sowie ausgeprägter veränderungen des verhaltens (fae) führt. schwere alkoholikerinnen trinken in der regel während der gesamten schwangerschaft.die häufigkeit des auftretens eines klassischen fetalen alkohol-syndroms bei einer alkoholkranken schwangeren liegt bei 10-30 % (abel 1999 , majewski 1978 , die inzidenz eines fas bei 1:1000 geburten (abel 1995). diese zahlen sind schätzwerte und hängen stark vom sozialen umfeld des jeweils untersuchten kollektivs ab. die diagnose fas wird bei geburt selten und die diagnose fae in der neugeborenzeit praktisch nie gestellt (little 1990 ). die häufigkeit der weniger ausgeprägten fae-kinder ist sicher deutlich höher und liegt etwa bei 4-5:1000 geburten (schöneck 1992) , dazu gibt es bisher keine größeren studien. das bild eines voll ausgeprägten fas ist gekennzeichnet durch eine prä-und postnatale dystrophie, mikrozephalie, mentale retardierung und minderwuchs. dazu gehören: eine typische kraniofaziale dysmorphie mit schmalen lidspalten (blepharophimose), schmalem lippenrot, kurzem breiten nasenrücken, langem unmodelliertem philtrum und geringgradig dysmorphen ohren sowie verschiedene fakultative organschädigungen, insbesondere herzfehler, nierenfehlbildungen und gaumenspalte sowie kleinere hautveränderungen. die diagnose kann prima vista gestellt werden.kinder mit fae weisen nur geringe dysmorphe störungen auf, außerdem können ein mikrozephalus, minderwuchs, eine diskrete mentale retardierung, aufmerksamkeitsstörungen (adhs) und oft ausgeprägte psychische verhaltensauffälligkeiten beobachtet werden. die diagnose gelingt nur bei bekanntem mütterlichem alkoholabusus.langzeituntersuchungen von kindern mit fas zeigen eine unerwartete persistenz des klinischen bildes. so bildet sich zwar die kraniofaziale dysmorphie langsam zurück, aber mikrozephalie, minderwuchs, aufmerksamkeitsstörungen und kognitive defizite bleiben. die schulleistungen verschlechterten sich trotz erheblicher förderung der kinder durch ihre pflegeeltern in einer 10-jahres-"follow-up"-studie ebenso wie ihre soziale integration. während der pubertät verstärken sich in der regel die probleme der betroffenen kinder, so dass auch zu diesem sicht in sasco 1999) . andere untersuchungen finden keine hinweise auf transplazentare karzinogenese (brondum 1999) . in einer schwedischen prospektiven studie, die insgesamt 1,4 millionen geburten einschloss, wurde der zusammenhang von mütterlichem rauchen in der schwangerschaft und kindlichem risiko für hirntumoren untersucht. die autoren fanden bei den raucherinnen einen signifikanten anstieg der häufigkeit von hirntumoren, jedoch keinen unterschied zwischen benignen und malignen tumoren. besonders betroffen waren 2-4-jährige kinder. die autoren interpretieren eine mögliche kausalität sehr vorsichtig (brooks 2004 , hersh 1985 . außerdem wurden bei über der hälfte von 35 untersuchten schwangeren vorzeitige wehen und frühgeburten beobachtet . toluol und andere organische lösungsmittel wurden auch hinsichtlich ihrer auswirkungen am arbeitsplatz untersucht. dort fand man z. t. hinweise auf erhöhte spontanabortraten (bukowski 2001 , taskinen 1994 , die bei toluol schnüffelnden schwangeren so nicht beobachtet wurden (bukowski 2001 pantanowitz 1996) . antiseren stehen bislang nicht im verdacht, entwicklungstoxisch zu wirken. sie können jedoch im falle einer mütterlichen anaphylaxie mittelbar auch den fetus gefährden.ein fallbericht über ein kind mit multiplen fehlbildungen, dessen mutter im 3. schwangerschaftsmonat von einer biene gestochen wurde (schneegans 1961) , hat anekdotischen charakter und belegt selbstverständlich keinen kausalzusammenhang.empfehlung für die praxis: die behandlung mit antiseren nach schlangenoder giftspinnenbissen darf nicht wegen der schwangerschaft unterbleiben. sie kann auch bei fehlen von vergiftungssymptomen der mutter indiziert sein, wenn unregelmäßigkeiten der fetalen herzaktion oder eine abnahme der kindsbewegungen beobachtet werden. g 2.22.6 pilze nach pilzvergiftung mit dem hochgiftigen knollenblätterpilz (amanita phalloides) erlitt eine patientin im ersten schwangerschaftsdrittel einen abort (kaufmann 1978) . das zyklische oktapeptidtoxin alpha-amanitin hemmt die proteinsynthese und kann über die plazenta hinweg die fetale leber schädigen. in einem weiteren fall brachte eine patientin nach vergiftung im 8. monat und erfolgreicher behandlung mit plas-berufliche exposition. zahnärztliches personal hat beruflich kontakt mit hg, daher wurden störungen der fruchtbarkeit vermutet. eine kleine studie mit messung der individuellen hg-belastung fand eine signifikante zunahme der abortrate (sikorski 1987) , andere untersuchungen konnten diesen effekt nicht bestätigen. eine häufung von fehlbildungen, mentaler retardierung und anderen funktionsstörungen ließ sich in keiner dieser arbeiten nachweisen . schwangeren auf den färöer inseln zeigten, dass der verzehr von seefischen und stark belastetem fleisch und fett von meeressäugern bei säuglingen zu einer konzentrationsabhängigen verschlechterung neurologischer testergebnisse führte (steuerwald 2000) . auch über kognitive defizite bei 7-jährigen kindern wurde im zusammenhang mit mütterlichem verzehr belasteter fische berichtet (grandjean 1997) . eine untersuchung an 740 "normal exponierten" mutter-kind-paaren auf den seychellen erbrachte hingegen keine mit der methylquecksilber-exposition korrelierenden entwicklungsdefizite bis zum alter von 9 jahren (myers 2003 (emory 2003) . ein um 10 ? g/dl höherer wert soll zu einem um 2-8 punkte schlechteren ergebnis im bayley-test führen (überblick bei wong 1992) . in einer mit blei belasteten region jugoslawiens wurden feinmotorische entwicklungseinschränkungen bei 283 kindern im alter von 4 1 ⁄2 jahren festgestellt, die mit den postnatal ermittelten bleikonzentrationen im blut korrelierten (wasserman 2000) . die exposition mit blei nach der geburt soll den ergebnissen der so genannten port-pirie-studie zufolge für einschränkungen der intelligenzentwicklung entscheidender sein als eine exposition während der schwangerschaft (baghurst 1992 , tong 1996 (gladen 2003) . bei den inuit (eskimos) fand man eine verringerung der körperlänge bei neugeborenen in abhängigkeit von der kontamination mit persistierenden organochlorverbindungen bei den müttern (dewailly 1993 (rogan 1999 ; siehe auch abschnitt 2.15.14 zu estrogenen und kapitel 1.12 zur exposition des vaters). neurologische auffälligkeiten bei "normaler" belastung. bei 141 neugeborenen von müttern, die mit pcbs belastete fische aus dem ontariosee (usa) verzehrt hatten, korrelierten abweichungen in verhaltenstests und bei autonomen reflexen mit einer erhöhten pcb-konzentration ( g 133 ng/g fett) im nabelschnurblut (stewart 2000) . eine kontamination der verzehrten fische mit anderen organischen umweltschadstoffen führte hingegen nicht zur beeinträchtigung der reaktionen beim neugeborenen. auch andere publikationen beschreiben abweichungen beim muskeltonus, beim visuellen erkennen und bei verschiedenen psychomotorischen eigenschaften bei neugeborenen und älteren kindern, deren mütter in der schwangerschaft vermehrt mit pcbs exponiert waren (übersicht in jacobson 1997) . es wird diskutiert, dass pcbs und dioxine durch die beeinträchtigung der fetalen schilddrüsenfunktion die zns-reifung stören und zu entwicklungsauffälligkeiten führen (koopman-esseboom 1994) . insgesamt vermitteln diese studien den eindruck, dass die vorgeburtliche exposition mit pcbs die entwicklung des kindes stärker beeinflusst als jene über die muttermilch (patandin 1999) .jacobsen und jacobson (1996) beschrieben psychomentale auswirkungen nach perinataler pcb-exposition und das fortbestehen intel-lektueller defizite bis zum alter von 11 jahren nach leicht erhöhten pcb-konzentration während der schwangerschaft, die von anderen autoren nicht bestätigt wurden (stewart 2003 , lackmann 2002 , middaugh 1997 .bei kindern, deren mütter während der schwangerschaft mit polybromierten biphenylen (pbbs) kontaminiertes fleisch gegessen hatten, wurde in michigan (usa) eine neuro-psychologische entwicklungsverzögerung festgestellt, die im alter von 4-6 jahren nicht mehr nachzuweisen war. das flammschutzmittel pbb war mit tierfutter verwechselt worden.empfehlung für die praxis: die vorliegenden erfahrungen sind unzureichend für eine differenzierte risikobeurteilung. es wird vermutet, dass persistierende halogenierte kohlenwasserstoffe in höherer dosis aborte, früh-und totgeburten und in sehr hoher dosis auch fehlbildungen verursachen können. die heute bei uns übliche umweltbelastung mit diesen stoffen führt offenbar nicht zu störungen des schwangerschaftsverlaufes oder einem erhöhten fehlbildungsrisiko. mögliche psychomotorische auswirkungen bei mäßig erhöhter exposition in der schwangerschaft sowie der geringe sicherheitsabstand zum tierexperimentell ermittelten noael bei polychlorierten dioxinen und furanen erfordern weiterhin energische präventivmaßnahmen. g 2. unter organischen lösungsmitteln versteht man zahlreiche -auch chlorierte -kohlenwasserstoffe, die leicht flüchtig und lipophil sind. dazu gehören aceton, benzol, ethylether, n-hexan, methyl-ethyl-keton, tetrachlorethen (per) , toluol, trichlorethen (tri), xylol. lösungsmittel werden farben und klebstoffen zugesetzt, zur chemischen reinigung benutzt und in großen mengen bei verschiedenen industriellen prozessen (entfettung, lederverarbeitung, nahrungsmittelherstellung etc.) eingesetzt. organische lösungsmittel können durch inhalation und über die haut aufgenommen werden. ihre biologische halbwertszeit kann -wie bei tetrachlorethen -mehr als 120 stunden betragen.besonderheiten in der schwangerschaft. für die meisten lösungsmittel wurde ein plazentarer übergang experimentell nachgewiesen.zur pränatalen exposition beim menschen gibt es einige falldarstellungen geschädigter kinder und retrospektive arbeiten, bei denen die auswirkungen von gemischen verschiedener lösungsmittel am arbeitsplatz untersucht wurden (überblick bei .mehrere berichte beschreiben kinder, deren mütter während der schwangerschaft lösungsmittel schnüffelten. intrauterine wachstums(boice 1994 , baverstock 1986 ). einen hinweis darauf, dass radioaktive nuklide bereits präkonzeptionell durch paternal-mutagene wirkung, d. h. nach strahlenexposition der väter, das malignomrisiko von kindern erhöhen können, ergaben studien an vätern mit einem arbeitsplatz in der kernbrennstoffaufbereitungsanlage sellafield in england (gardner 1987) . eine umfangreiche analyse von ca. 250.000 geburten in der umgebung von sellafield in der zeit von 1950-1989 zeigte auch eine erhöhte rate von totgeburten bei solchen vätern (parker 1999) . eine andere untersuchung an über 11.000 in der britischen atomindustrie beschäftigten männern und knapp 2.000 beschäftigten frauen ergab nur für die präkonzeptionell exponierten frauen ein erhöhtes fehlgeburtsrisiko, totgeburten waren jedoch nicht häufiger, auch nicht die fehlbildungen (doyle 2000) . 