Iraqi J Pharm Sci, Vol.24(1) 2015 Captopril and bone metabolism 11 Study the Influence of Captopril on Bone Metabolism in Elderly Hypertensive Women Zahraa A. Mousa * , Nada N. Al-Shawi **, 1 and Ahmed A. Omar * * Ministry of Health, Al-Yarmouk Teaching Hospital, Baghdad,Iraq. ** Department Pharmacology and Toxicology, College of Pharmacy, University of Baghdad,Baghdad,Iraq. Abstract Widespread use of antihypertensive agents in clinical practice necessitates the knowledge of their pleiotropic effects. At the present time there are no sufficient evidences of positive effect of these medications on bone coming from randomized controlled trials; knowledge of additional effects of those drugs on the bone metabolism will allow doctors to choose optimal treatment of hypertension, taking into account the state of bone tissue. At the same time it will also allow to prevent osteoporosis in patients having osteoporosis risk factors or initial signs of bone loss. Ten elderly hypertensive women age > 60 years old (64.2±3.6) treated with captopril for a 5-6 years ago while they attending Al Yarmouk Teaching Hospital in Baghdad; in addition, newly- diagnosed hypertensives, and normotensive of the aged-matched women were participated in this study that were conducted during the period (January- May 2014). Measurement of serum calcium, magnesium, inorganic phosphorus, total alkaline phosphatase activity, and parathyroid hormone were done, in addition to spine mineral density and t-score of such bone density by dual energy x-ray absorptiometry. The results of this study showed that there were no significant differences in the serum levels of calcium, magnesium, inorganic phosphorus, total alkaline phosphatase activity, and parathyroid hormone in postmenopausal hypertensive women treated for 5-6 years with captopril compared to newly-diagnosed and to aged-matched normotensive women. In addition, non-significant differences were observed in the level of bone mineral density and t score of bone mineral density in all groups of the study. In conclusion, the present study provides additional knowledge concerning the influence of captopril treatment on some selected parameters of bone metabolism in elderly hypertensive women. Keywords: Captopril, Bone metabolism, Elderly women, Hypertension, Dual energy x-ray absorptiometry. الكبيرات في السن والالتي يعانين العظن في النساء استقالبعلى عقار الكابتىبريلدراسة تأثير هن ارتفاع ضغط الدم زهراء عامر موسي * ، ندى ناجٌ الشاوً **،1 و أحمد عبد البارً عمر * * العراق.،بغداد ،وزارة الصحت ،مستشفي الَرموك التعلَمٌ ** .، العراقجامعت بغداد،كلَت الصَدلت، فرع األدوٍت والسموم الخالصة االستخدام السرٌري الواسع لالدوٌة الخافضة لضغط الدم ٌتطلب معرفة التأثٌرات االخرى الغٌر متعارف علٌها. فً الوقت الحاضر لٌس هناك دالئل واضحة حول التأثٌرات األٌجابٌة لتلك األدوٌة على العظم كما ان المعرفة االضافٌة لتأثٌراتها على استقالب ٌار افضل دواء لعالج ارتفاع ضغط الدم مع االخذ بنظر االعتبار حالة النسٌج العظمً. وفً نفس الوقت العظم تسمح لالطباء باخت ٌمنع ذلك تخلخل العظام فً المرضى الذٌن لدٌهم عوامل خطورة تسبب تخلخل العظم أو لدٌهم أعراض أولٌة من خسارة العظم لذلك تقالب العظم فً النساء اللواتً ٌعانٌن من ارتفاع ضغط الدم، وألضافة اراء على اس صممت هذه الدراسة الستقصاء تأثٌرالكابتوبرٌل سنة وٌعانٌن من ارتفاع ضغط الدم 06الى تلك التً تمت من قبل باحثٌن بهذا الخصوص. تم مشاركة عشر نساء اعمارهن أكثر من مستشفى الٌرموك التعلٌمً فً بغداد، باالضافة سنوات خالل زٌارتهن ل 0-5عولجن من قبل أطباء أختصاص بعقار الكابتوبرٌل لمدة الى عشر نساء لدٌهن ارتفاع فً ضغط الدم شخصن حدٌثا، وعشر نساء لدٌهن ضغط دم طبٌعً وبنفس العمر. تم قٌاس معدالت ل الدم وهرمون الباراثاٌروٌد فً مص Alkaline phosphataseانزٌم ال الكالسٌوم، المغنٌسٌوم، الفوسفور الالعضوي، فعالٌة باستخدام الجهاز الممتص لالشعة السٌنٌة. t-scoreو لكل النساء المشاركات فً الدراسة، كما تم قٌاس كثافة معادن العمود الفقري انزٌم أظهرت نتائج الدراسة بان لٌس هناك اختالفات معنوٌة فً معدالت الكالسٌوم، المغنٌسٌوم، الفوسفور الالعضوي، فعالٌة سنوات 0-5وهرمون الباراثاٌروٌد لدى النساء فً سن الٌأس الالتً ٌستخدمن الكابتوبرٌل لمدة Alkaline phosphatase لـا عند زٌارتهن الى المستشفى والنساء حدٌثا تشخٌصه تم لعالج ارتفاع ضغط الدم بالمقارنة مع اللواتً لدٌهن ارتفاع فً ضغط الدم 1 Corresponding author E-mail: nadaalshawi@yahoo.com Received: 29 /9/2014 Accepted: 16 /12/2014 mailto:nadaalshawi@yahoo.com Iraqi J Pharm Sci, Vol.24(1) 2015 Captopril and bone metabolism 12 -tضغط دم طبٌعً وبنفس العمر. باالضافة الى ذلك، لٌس هناك اختالفات معنوٌة فً معدل كثافة معادن العظم و فً الالتً لدٌهن score ًلكثافة معادن العظم فً النساء الالتً ٌعانٌن من ارتفاع ضغط الدم وٌستخدمن الدواء بالمقارنة مع معدالته فً النساء الالت لدٌهن ارتفاع فً ضغط الدم عند زٌارتهن الى المستشفى، والنساء الالتً لدٌهن ضغط دم طبٌعً. ن هذه الدراسة اضافت معرفة حول تأثٌر عقار الكابتوبرٌل على معدالت وفقا للنتائج التً تم الحصول علٌها ٌمكن االستنتاج بأ المعاٌٌر التً اختٌرت فً الدراسة والخاصة باستقالب العظم فً النساء المسنات الالتً لدٌهن ارتفاع فً ضغط الدم. السينية . الووتص لألشعةعقار الكابتىبريل ،استقالب العظن ،النساء الكبيرات في السن ، ارتفاع ضغط الدم ، الجهاز :الكلوات الوفتاحية Introduction Hypertension and osteoporosis are two major age-related disorders that together account for significant morbidity and mortality in the elderly. As 50% of the hypertensive population comprises postmenopausal women at high risk of osteoporosis, hypertension represents a considerable health problem in this population. Several studies suggested that high blood pressure is associated with abnormalities of calcium metabolism, leading to an increase in calcium movement from bone, thereby increasing the risk of osteoporosis (1-3) while, others did not show such association (4-6) . It has been also demonstrated that bone metabolism is closely regulated by hormones and cytokines, which have effects on both bone resorption and deposition. Because the vasculature plays an important role in bone remodeling, the effect of the renin angiotensin system on bone metabolism may be partially related to the regulation of blood flow. Although, the receptors for angiotensin II is expressed in osteoblasts and osteoclasts but, the effects of such peptide hormone are controversial; however, several investigators indicated that angiotensin II is a potent stimulator of osteoclastic bone resorption; on the contrary, others showed that angiotensin II stimulated the proliferation of osteoblast - rich populations of cells (7-8) . In vivo study demonstrated that captopril may improve osteopenia in ovariectomised rats and may promote bone formation in osteoblasts (9) . Conflicting data were demonstrated by several clinical studies concerning the influence of angiotensin converting enzyme inhibitors and abnormalities of bone metabolism (10-11) . Thus, this study was designed to investigate the influence of captopril on bone metabolism in elderly hypertensive women; and to add suggestions to that performed by other researchers concerning this respect. Women, Materials and Methods Ten hypertensive women on captopril therapy (daily dose range 12.5-100mg; Midochemie LTD, Limassol-Cyprus), treated by specialist physicians while attending Al Yarmouk Teaching Hospital in Baghdad (Group C); ten newly-diagnosed hypertensives (Group B); and ten apparently healthy (Group A) were participated in this study. The study was approved by the Scientific Committee of the College of Pharmacy-Baghdad University; in addition, an ethical sheet was obtained and approved by the Ministry of Health, Baghdad- Iraq. Verbal consent was obtained from each woman participated in this study. The inclusion and exclusion criteria of all women in this study are summarized in table 1, and their demographic data are showed in table 2. Table (1) : Inclusion and exclusion criteria of women enrolled in this study Inclusion criteria Exclusion criteria - Over sixty years old normotensive women. - Over sixty years old patients’ women with hypertension. Disease Rheumatoid disease Diabetic mellitus Cardiovascular diseases Hepatic and renal dysfunctions Smoking Drugs, and supplements Thyroxin Corticosteroids Estrogen and its derivative Bisphosphonates Nutritional supplements Diuretics Iraqi J Pharm Sci, Vol.24(1) 2015 Captopril and bone metabolism 13 Table (2): Groups of women who participated in the present study Group Number of women Age Systolic/Diastolic blood pressures mm Hg Body mass index (BMI) Group A 10 66.4±4.6 130/86±3.1 a 28.3±4.4 a Group B 10 66.1±5.8 NS 140/95±2.9 b 32.0±5.1 b Group C 10 64.2±3.6 NS 130/85±3.8 a 33.2±5.2 b - Group A: normotensive elderly control women; Group B: elderly women newly diagnosed with hypertension; Group C: elderly hypertensive women treated with therapeutic dose of captopril [Midochemie LTD, Limassol-Cyprus; (dosage range 12.5-100mg)]. - Values of age, systolic/diastolic blood pressures, and body mass index (BMI) are presented as mean ±standard error of mean. - Values with non-identical superscripts (a, and b) are considered significant. - NS: non-significant difference compared to normotensive controls (Group A). The body mass index (BMI) was calculated using the following formula: weight in ilogram height 2 (in meter) (12) ; while systolic/diastolic blood pressures were measured utilizing sphygmomanometer and stethoscope (13). Blood sampled were collected from each women participated in the study for laboratory analysis to measure serum calcium (Ca ++ ) (Roche/Hitachi, Germany) (14) magnesium (Mg ++ ) (Roche/Hitachi, Germany) (15) , inorganic phosphorus (Pi) (Roche/Hitachi, Germany) (16) , alkaline phosphatase (ALP) (Roche/Hitachi, Germany) [17], and parathyroid hormone (PTH) (Roche/Hitachi, Germany) [18] by utilizing kits for this purpose. Besides, all women were examined by x-ray to measure spine mineral density utilizing dual X-ray absorptiometry (DEXA) (19) , and (t) score of such bone mineral density (20) . Statistical Analysis Analysis of data was carried out using the Statistical Packages for Social Sciences- version 22 (SPSS-22). The significance of difference among groups of women concerning their age, weight, height and mean arterial blood pressure was tested using Pearson Chi-square test ( 2 test) with application of Yate's correction or Fisher Exact test whenever applicable. Besides, the significance of difference of different means was tested using Student-t-test for difference between two independent means. Statistical significance was considered whenever the P value was equal or less than 0.05 in all data presented in this study. Results Hypertensive elderly women treated with therapeutic doses of captopril, for 5-6 years showed non-significant differences (P>0.05) in the levels of serum calcium, magnesium, and inorganic phosphorus compared to normotensive elderly controls and to newly- diagnosed hypertensive women of the aged- matched as shown in table 3. Table (3): Influence of captopril on serum calcium, magnesium, and inorganic phosphorus compared to normotensive elderly controls, and to newly-diagnosed elderly women. Group Serum Calcium mg/dl Serum Magnesium mg/dl Serum Inorganic Phosphorus mg/dl Group A 9.00±1.05 2.13±0.11 3.01±0.63 Group B 8.96±0.95 2.11±0.24 3.59±0.78 Group C 8.62±0.84 2.24±0.19 3.46±0.54 Group A: normotensive elderly control women; Group B: elderly women newly diagnosed with hypertension; Group C: elderly hypertensive women treated for 5-6 years with therapeutic dose of captopril. - Values are presented as mean± standard error of mean. - Number of women in each group is 10. Iraqi J Pharm Sci, Vol.24(1) 2015 Captopril and bone metabolism 14 The data presented in table 4 showed non- significant differences (P>0.05) in the serum activity of ALP , and the level of serum PTH levels in elderly hypertensive women treated for 5-6 years with captopril compared to the corresponding levels in newly-diagnosed and to normotensive control women. Table (4): Influences of captopril on serum alkaline phosphatase (ALP) activity and serum parathyroid hormone compared to normotensive elderly controls, and to newly-diagnosed elderly women. Group Alkaline phosphatase(U/L) Parathyroid Hormone pg/ml Group A 90.00±34.55 44.24±16.89 Group B 90.50±23.11 54.77±43.74 Group C 71.82±20.49 47.34±15.56 Group A: normotensive elderly control women; Group B: elderly women newly diagnosed with hypertension; Group C: elderly hypertensive women treated for 5-6 years with therapeutic dose of captopril. - Values are presented as mean± standard error of mean. - Number of women in each group is 10. The data presented in table 5 showed non- significant (P>0.05) differences in the levels of spine mineral density, and (t) score in elderly hypertensive women treated for 5-6 years with therapeutic dose of captopril compared to those levels in normotensive elderly controls and to newly-diagnosed hypertensive of the aged-matched women. Table( 5): Influence of captopril on spine, and (t) score of such bone mineral density (BMD). Group Spine Mineral Density (mg. cm -2 ) Spine Mineral Density (t) Score Group A 777.60±113.52 2.74±0.92 Group B 803.40±153.37 2.41±0.95 Group C 841.90±169.65 2.44±1.34 Group A: normotensive elderly control women; Group B: elderly women newly diagnosed with hypertension; Group C: elderly hypertensive women treated for 5-6 years with therapeutic dose of captopril. - Values are presented as mean± standard error of mean. - Number of women in each group is 10. Discussion It has been reported that Ang II may influence calcium metabolism by decreasing ionized calcium and increasing the PTH level (21) . Conflicting results were obtained concerning the effects of angiotensin converting enzyme inhibitors on bone metabolism; where, patients with risk of fractures who have used angiotensin converting enzyme inhibitor (ACEI), no significant difference in BMD were recorded (22) ; while other study reported that patients treated with an ACEI showed an increased BMD and more importantly reduced fracture risks (10,11) . However, ACEIs also regulate the bradykinin-nitric oxide (NO) pathway as well as block Ang II production, different from angiotensin receptor blockers (ARBs). It was well known that the NO pathway regulates local blood flow in bone marrow capillaries, which might enhance bone marrow formation. Thus , the contribution of the NO pathway might have a role in the prevention of osteoporosis by ACE inhibition (23) . An in vitro study performed by Liu et al in 2011demonstrated that captopril had potential effects of improving lumbar vertebral bone strength in aged ovariectomised (OVX) rats and promoted osteoblast bone formation (9) . Moreover, the same study showed that the administration of an ACE inhibitor, enalapril, did not cause significant changes in bone density, mineral content or morphometric parameters of the femur in 14-week-old ovariectomised female Wistar rats. Captopril acts by inhibiting the conversion of angiotensin I to Ang II; thus inhibits the synthesis and secretion of aldosterone and Iraqi J Pharm Sci, Vol.24(1) 2015 Captopril and bone metabolism 15 reduces blood pressure. The drug also reduces the bradykinin degradation thus, inhibiting the generation of prostaglandins that were considered as local factors that may stimulate bone resorption (24) . It has been demonstrated that in vasculature, estrogen antagonized Ang II signaling and Ang II induced atherosclerosis, which suggest that OVX might accelerate Ang II-induced signaling. Of importance, several reports suggest that estrogen may enhance the ACE inhibition-mediated improvement of vascular remodeling in hypertension in female {(spontaneously hypertensive rats (SHR)} with OVX through the inhibition of extracellular signal-regulated kinase 1/2. It supports the impact of a cross talk between estrogen and Ang II signaling in SHRs females (25,26) . Concerning magnesium (Mg), the result of the present study revealed that no significant differences in the level of serum Mg were observed in all elderly women groups participated in this study. Such electrolyte works in concert with calcium to regulate electrical impulses in the cells; also it is largely responsible for the bone health and strong teeth. Without adequate amounts of the Mg, calcium will not be deposited in these hard tissues, where, Mg has the ability to activate thyrocalcitonin, a hormone that under normal circumstances would send calcium to bones. Furthermore, many authors demonstrated that there was a functional link between Mg and calciotropic hormones such as parathyroid hormone (PTH) and 1, 25(OH) 2 vitamin D3 that all responsible for the regulation of calcium homeostasis (27,28) . Regarding inorganic phosphorus, the intended element is present in every cell of the body, and 85% of the body's phosphorus is found in bones and teeth. Thus, it is vital to the formation of bones and teeth, and healthy bones and soft tissues require calcium and phosphorus to grow and develop throughout life (29) . The tight controlled balance of calcium and phosphorus is maintained by hormonal control of transport in the intestine, bone, and kidney; where, the latter organ acts by modulating calcium and phosphate reabsorption from the glomerular filtrate according to the body needs that is mediated by ion transporters. In addition to the classical endocrine factors (such as PTH and vitamin D) that are involved in maintaining calcium and phosphate balance, other factors have been identified viz, fibroblast growth factor-23 (FGF23), which regulates urinary phosphate excretion by interacting with FGF receptors; and Klotho, a transmembrane protein, facilitates this interaction, with the result of reducing phosphate reabsorption by the kidney. Furthermore, dental matrix protein-1, an osteocyte product, has been shown to participate in FGF23-mediated regulation of phosphorus homeostasis (30) . Furthermore, the impacts of ACEIs have been studied in stable ischemic heart disease; in such study, the intended group of drugs showed a beneficial effect on FGF-23 regardless of renal function (31) . The effects of captopril utilized in the present study on serum inorganic phosphorus (Pi) were non-significantly different among all elderly women participated in this work which could be attributed to the above regulatory processes. Thus, further works are needed to emphasize the findings of the investigators. The present study provides additional knowledge concerning the influence of captopril treatment on some selected parameters of bone metabolism in postmenopausal hypertensive women. Conclusion According to the results obtained from this study, one can conclude that, there were no significant differences in the serum levels of electrolytes (calcium, magnesium, and inorganic phosphorus); parathyroid hormone,; alkaline phosphatase activity, in addition to bone mineral density in hypertensive elderly women treated with therapeutic doses of captopril, for 5-6 years compared to normotensive elderly controls and to newly- diagnosed hypertensive women of the aged- matched. Acknowledgments The authors thank the laboratory technicians of Al-Yarmouk Teaching Hospital for analyzing biochemical parameters, and for DXA scanning. References 1. Tsuda, K; Nishio, I. and Masuyama, Y. Bone mineral density in women with essential hypertension. Am J Hypertens. 2001; 14: 704-707. 2. Yazici, S; Yazici, M; Korkmaz, U et al. Relationship between blood pressure levels and bone mineral density in postmenopausal Turkish women. Arch Med Sci. 2011; 7: 264-270. 3. Yang, S; Nguyen, ND; Center, JR. et al. Association between hypertension and fragility fracture: a longitudinal study. Osteoporosis International 2013: 1-7. 4. Pérez-Castrillón, JL; Justo, I; Silva, J et al. Bone mass and bone modelling markers in Iraqi J Pharm Sci, Vol.24(1) 2015 Captopril and bone metabolism 16 hypertensive postmenopausal women. J Hum Hypertens. 2003; 17: 107-110. 5. Lidfeldt, J; Holmdahl, L; Samsioe, G et al. The influence of hormonal status and features of the metabolic syndrome on bone density: a population-based study of Swedish women aged 50 to 59 years. The women’s health in the Lund area study. Metabolism: clinical and experimental 2002; 51: 267-270. 6. Olmos, JM; Hernández, JL; Martínez, J et al. Bone turnover markers and bone mineral density in hypertensive postmenopausal women on treatment. Maturitas. 2010; 65: 396-402. 7. Jilka RL. Weinstein RS, Bellido T et al. Osteoblast programmed cell death (apoptosis): modulation by growth factors and cytokines. J Bone Miner Res 1998; 13: 793-802. 8. Teitelbaum, SL and Ross, FP. Genetic regulation of osteoclast development and function. Nat Rev Genet 2003; 4: 638– 649. 9. Liu, YY; Yao, WM; Wu, T et al. Captopril improves osteopenia in ovariectomized rats and promotes bone formation in osteoblasts. J Bone Miner. Metab. 2011; 29(2):149-58. 10. Lynn, H; Kwok, T; Wong, SY et al. Angiotensin converting enzyme inhibitor use is associated with higher bone mineral density in elderly Chinese. Bone 2006; 38: 584–8. 11. Azizi, M; Chatellier, G; Guyene, TT et al. Additive effects of combined angiotensin- converting enzyme inhibition and angiotensin II antagonism on blood pressure and renin release in sodium- depleted normotensives. Circulation 1995; 92(4):825–834. 12. MacKay, N.J. "Scaling of human body mass with height: The body mass index revisited". Journal of Biomechanics 2010; 43 (4): 764–6. 13. Ganong's Review of Medical Physiology, 24 th Edition , Tata McGraw - Hill Edition . Barrett , KE; Barman, SM; Boitano, S. and Brook, HL. 2012. 14. Burtis C.A., Ashwood E.R. Tietz Textbook of Clinical Chemistry 3 rd ed. Philadelphia, PA: WB Saunders, 1999b; 345. 15. Ratge, D., Kohse, K.P., and Wisser, H.; Measurement of Magnesium in Serum and Urine with a Random Access Analyzer by use of a Modified Xylidyl Blue-1 Procedure, Clinical Chimica Acta 1986; 159: 197-203. 16. Burtis C.A and Ashwood E.R. Tietz Textbook of Clinical Chemistry 2 nd ed. Philadelphia, PA: WB Saunders, 1994a:1909. 17. Burtis C.A., Ashwood E.R. Tietz Textbook of Clinical Chemistry 3 rd ed. Philadelphia, PA: WB Saunders, 1999b; 1642. 18. Forster RJ, Bertoncello P, Keyes TE. "Electrogenerated Chemiluminescence". Annual Review of Analytical Chemistry 2009; 2: 359–85. 19. Bradford, R. "Osteoporosis and bone mineral density." American College of Radiology. Retrieved 2008-05-11. 20. Cranney A, Jamal SA, Tsang JF, Josse RG, Leslie WD. "Low bone mineral density and fracture burden in postmenopausal women". Canadian Medical Association Journal 2007; 177 (6): 575–80. 21. Grant, FD; Mandel, SJ; Brown, EM et al. Interrelationships between the renin- angiotensin-aldosterone and calcium homeostatic systems. J Clin Endocrinol Metab 1992; 75: 988–992. 22. Nakagami, H; Osako, M.K. and Morishita, R. “Potential effect of angiotensin receptor blockade in adipose tissue and bone,” Current Pharmaceutical Design. 2013; 19 (17): 3049–3053. 23. Broulik, PD; Tesar, V; Zima, T and Jirsa, M. Impact of antihypertensive therapy on the skeleton: effects of enalapril and AT1 receptor antagonist losartan in female rats. Physiol Res 2001; 50: 353–358. 24. Cole, RE. "Improving clinical decisions for women at risk of osteoporosis: dual- femur bone mineral density testing". J Am Osteopath Assoc. 2008; 108(6): 289–95. 25. Takeda-Matsubara, Y; Nakagami, H; Iwai, M et al. Estrogen activates phosphatases and antagonizes growth-promoting effect of angiotensin II. Hypertension 2002; 39: 41–45. 26. Tsuda, M; Iwai, M; Li, JM et al. Inhibitory effects of AT1 receptor blocker, olmesartan, and estrogen on atherosclerosis via anti-oxidative stress. Hypertension 2005; 45: 545–551. 27. Wallach, S . Effects of magnesium on skeletal metabolism. Magnesium and Trace Elements 1990, 9(1):1-14. 28. Zofková, I and Kancheva, RL. The relationship between magnesium and calciotropic hormones. Magnesium Research: Official Organ of the International Society for the Development of Research on Magnesium1995; 8(1):77- 84. http://www.ncbi.nlm.nih.gov/pubmed?term=Liu%20YY%5BAuthor%5D&cauthor=true&cauthor_uid=20686802 http://www.ncbi.nlm.nih.gov/pubmed?term=Yao%20WM%5BAuthor%5D&cauthor=true&cauthor_uid=20686802 http://www.ncbi.nlm.nih.gov/pubmed?term=Wu%20T%5BAuthor%5D&cauthor=true&cauthor_uid=20686802 http://www.ncbi.nlm.nih.gov/pubmed/20686802 http://www.ncbi.nlm.nih.gov/pubmed/20686802 http://arjournals.annualreviews.org/doi/abs/10.1146/annurev-anchem-060908-155305 http://www.guideline.gov/summary/summary.aspx?ss=15&doc_id=11559&nbr=5990 http://www.guideline.gov/summary/summary.aspx?ss=15&doc_id=11559&nbr=5990 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1963365 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1963365 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1963365 http://www.jaoa.org/cgi/pmidlookup?view=long&pmid=18587077 http://www.jaoa.org/cgi/pmidlookup?view=long&pmid=18587077 http://www.jaoa.org/cgi/pmidlookup?view=long&pmid=18587077 http://europepmc.org/search?page=1&query=AUTH:%22Wallach+S%22 http://europepmc.org/search?page=1&query=ISSN:%221015-3845%22 http://europepmc.org/search?page=1&query=ISSN:%221015-3845%22 http://europepmc.org/search?page=1&query=AUTH:%22Zofkov%C3%A1+I%22 http://europepmc.org/search?page=1&query=AUTH:%22Kancheva+RL%22 http://europepmc.org/search?page=1&query=ISSN:%220953-1424%22 http://europepmc.org/search?page=1&query=ISSN:%220953-1424%22 http://europepmc.org/search?page=1&query=ISSN:%220953-1424%22 http://europepmc.org/search?page=1&query=ISSN:%220953-1424%22 Iraqi J Pharm Sci, Vol.24(1) 2015 Captopril and bone metabolism 17 29. Heaney, RP and Nordin, B.E. Calcium effects on phosphorus absorption: implications for the prevention and co- therapy of osteoporosis. J Am Coll Nutr 2002; 21(3):239-244. 30. Civitelli, R and Ziambaras, K. Calcium and phosphate homeostasis: concerted interplay of new regulators. J Endocrinol Invest. 2011 Jul; 34(7 Suppl):3-7. 31. Udell, J.A; Morrow, D. A; Jarolim, P et al. Fibroblast Growth Factor-23, Cardiovascular Prognosis, and Benefit of Angiotensin-Converting Enzyme Inhibition in Stable Ischemic Heart Disease. J Am Coll Cardiol. 2014; 63(22):2421-2428. doi: 10. 1016/j.jacc.2014.03.026. http://www.ncbi.nlm.nih.gov/pubmed/?term=Civitelli%20R%5BAuthor%5D&cauthor=true&cauthor_uid=21985972 http://www.ncbi.nlm.nih.gov/pubmed/?term=Ziambaras%20K%5BAuthor%5D&cauthor=true&cauthor_uid=21985972 http://www.ncbi.nlm.nih.gov/pubmed/21985972 http://www.ncbi.nlm.nih.gov/pubmed/21985972