Stesura Seveso 263Archivio Italiano di Urologia e Andrologia 2020; 92, 3 ORIGINAL PAPER No conflict of interest declared. DOI: 10.4081/aiua.2020.3.263 L-carnitine as primary or adjuvant treatment in infertile patients with varicocele. A systematic review Georgios Tsampoukas 1, 4, Muhammad Faisal Khan 2, Antigoni Katsouri 3, Waseem Akhter 4, Mohamad Moussa 5, Konstantinos Deliveliotis 6, Athanasios Papatsoris 1, 6, Noor Buchholz 1 1 U-merge Ltd. (Urology for emerging countries), London, UK*; 2 Department of Urology, North Devon hospital, Barnstaple, UK; 3 Department of Pharmacy, University of Patras, Patras, Greece; 4 Department of Urology, Princess Alexandra Hospital, Harlow, UK; 5 Al Zahraa Hospital, University Medical Center, Lebanese University, Beirut, Lebanon; 6 2nd Department of Urology, University Hospital of Athens, Athens, Greece. * U-merge Ltd. (Urology for Emerging Countries) ) is an academic urological platform dedicated to facilitate knowledge transfer in urology on all levels from developed to emerging countries. U-merge Ltd. is registered with the Companies House in London/ UK. www.U-merge.com Background: Varicocele has been found to impair the function of the epididymis resulting in subfertility whereas the varicocelectomy can resolve the phenomenon. L-carnitine is regarded as a bio- marker for the function of the epididymis and has been found in reduced concentrations in infertile patients of various caus- es, including infertile men with varicocele. It seems that L- carnitine and varicocele share clinical significance and the area of research looks promising. Objective: To identify the role of L-carnitine in the treatment of varicocele. Materials and methods: A systematic search was performed in Pubmed/Medline with the terms (L-carnitine) and (varico- cele) and (L-carnitine) and (varicocelectomy). Inclusion crite- ria were studies reported outcomes of L-carnitine administra- tion alone or in duet, as primary or adjuvant treatment to varicocele. Exclusion criteria were non-English language and animal studies. Studies using L-carnitine as part of a panel of therapeutic agents were avoided. Results: Only four suitable studies were identified for discus- sion. In one randomized study, the combination of L-carnitine and cinnoxicam improved semen parameters in patients with non-high-grade varicocele compared to L-carnitine alone and had a favourable effect on pregnancy rates but the effect of grade is unknown. In another study, as an adjuvant treat- ment to varicocelectomy, L-carnitine showed no clear benefit. Finally, in comparison to surgery, the results are inconclu- sive; two studies showed some benefit might be expected in low-grade or subclinical varicocele, but surgery appears superior. Conclusions: The evidence regarding the role of L-carnitine as a primary or adjuvant treatment of varicocele is sparse. The pathophysiological significance of L-carnitine implicates a potential role of the molecule in the management of varico- cele, but the evidence so far is controversial for any recom- mendations. L-carnitine might be taken into consideration in selected cases; however, further search is needed in order the optimal role of L-carnitine in infertile patients with varicocele to be clarified. KEY WORDS: Varicocele; Male infertility; L-carnitine; Antioxidants; Varicocelectomy. Submitted 2 March 2020; Accepted 15 March 2020 Summary INTRODUCTION - BACKGROUND Varicocele is considered one of the most common treat- able causes of male infertility (1). The interventional or surgical approach is considered the standard of care for the condition in case of infertility due to favourable outcomes regarding improvement in semen parameters and pregnancy rates (2). In modern era, research has also focused on the varicocele-induced oxidative stress and reduction in antioxidant capacity which results in impaired spermatogenesis, broadening new horizons in the treatment of the condition (3, 4). Antioxidative treatment is well-established in idiopathic infertility and oligoasthenoteratospermia (OAT), albeit the results still conflicting and the optimal agents or combination still lacking (5). Among the investigated agents, L-carni- tine (LC) has shown effectiveness on ameliorating oxida- tive stress, improving semen parameters in infertile patients (6-9). Additionally, the molecule has a signifi- cant physiological role and the measurement of seminal L-carnitine is used as biomarker for the assessment of epididymal function in patients with various fertility issues including varicocele (10, 11). The measurement of L-carnitine in the semen is mean- ingful and clinical relevant as a positive correlation between seminal carnitine levels and several semen parameters including motility, concentration and DNA quality has been shown in infertile patients with varico- cele (12). All the above render LC as a potent biomark- er during the evaluation of infertile patients with varico- cele and as a potential target in the treatment of such patients as well. In this review, we explore the role of LC in the potential management of varicocele. MATERIALS AND METHODS We performed an systematic literature search using the advanced search engine in PubMed/Medline with the terms (L-carnitine) and (varicocele) and (L-carnitine) and (varicocelectomy). The results were checked for duplicates in Mendeley. Our search targeted studies reporting conclusions relating to Archivio Italiano di Urologia e Andrologia 2020; 92, 3 G. Tsampoukas, M. Faisal Khan, A. Katsouri, W. Akhter, M. Moussa, K. Deliveliotis, A. Papatsoris, N. Buchholz 264 the role of carnitine management of varicocele. Only stud- ies using L-carnitine alone or in duet were included and studies reporting results with combination of multiple antioxidants were avoided. Animal studies, case reports and articles in non-English language were excluded; reviews were also excluded from the literature search but were screened independently for the identification of other sources. The flowchart of our strategy is presented on Figure 1. The risk of bias assessment of the selected studies is illus- trated on Figure 2. RESULTS (Table 1) Performance of L-carnitine in infertile patients with varicocele as sole treatment One study was identified reporting the benefit of LC administration in semen parameters of infertile patients with varicocele-induced OAT. Cavallini et al. randomized patients into 3 groups, group 1 given placebo only, group 2 given oral LC (2 g/d)/acetyl-L-carnitine (1 g/d) and placebo suppository and group 3 given oral LC and suppository cinnoxicam 30 mg every 4 days; the medication were given for a total dura- tion of 6 months whereas the varicocele was graded according to the severity of venous reflux into 5 grades, with grades 1-2 corresponding to subclinical varicocele and grades 3-5 correspon- ding to clinical grades I, II and III respectively (13). The authors observed that the combination group had signifi- cantly increased sperm parameters at 3 and 6 months compared to other groups in patients with grade 1 to 4 whereas the effect was durable as long as patients were on the medication; on the other hand, no treatment made any difference in grade 5 varicoceles. Thus, the authors concluded that the combination of LC and cin- noxicam suppositories proved a reliable treatment for low- grade varicoceles in terms of semen parameters but not efficient for high grades; notably, the pregnancy rates were also raised in group 3 but there was no special comment regarding the varicocele grade contribution (13). Performance of L-carnitine in comparison to varicocelectomy Two studies reported outcomes of varicocelectomy com- pared to administration of LC. In one study, Sofimajidpour et al allo- cated 62 patients with a mean age of 29 years and mean infertility duration of 3.3 years with clinical varicocele grade II or more into two groups; thirty-one patients were administrated an oral dose of 250 mg LC four times a day for six months and 31 patients underwent varicocelectomy (14). Both groups showed significant improvement in semen parameters including sperm count, motility, morphology and semen volume while no difference was observed between groups (14). Notably, the study was not random- ized and the groups differed signifi- cantly in terms of clinical grade (the 87.1% of the participants in the medic- inal group had grade II varicocele in comparison to 25.8% of patients in the Figure 1. PRISMA 2009 Flow Diagram. Figure 2. Risk of bias of the selected studies. surgery group); therefore, it seems that LC supplementa- tion might be an alternative to surgery in infertile patients with grade II varicocele in terms of semen parameters (14). In a retrospective study of 143 infertile patients with left subclinical varicocele, the authors had allocated the participants into 3 groups according to their preference: a surgery group was treated with micro- surgical varicocelectomy, a medical group with 3 g of LC orally for at least 6 months and an observation group including patients deciding no treatment (15). The oper- ation increased the sperm count significantly whereas the pregnancy rate raised to 60%; on the contrary, the LC administration did not offer any benefit in terms of semen parameters but the pregnancy rate was 34.5% dif- fering significantly to observation group (18.7%) (15). Performance of L-carnitine as adjuvant treatment to varicocelectomy Pourmand et al randomized 100 infertile patients with clinical and subclinical varicocele and dyspermia into two groups; the first group underwent varicocelectomy alone whereas patients in the second group were given adjuvant 750-mg oral LC a day for 6 months (16). The study failed to show any benefit of the adjuvant administration of the agent as neither the semen param- eter improvement nor DNA damage reduction differed significantly in the patients underwent combined treat- ment in comparison to the surgery alone group; howev- er, the slope of improvement for morphology and motil- ity was better in the combination treatment group (16). DISCUSSION We decided to investigate the role of LC in the manage- ment of varicocele for two main reasons. Firstly, the epi- didymis is considered the main supply of LC to the semen, providing around the 95% of the total amount and this is why seminal LC has been proposed as a mark- er for the assessment of the functional capacity of the organ (17, 18). The finding is significant as LC acts as a co-factor for the mitochondrial transport and the subse- quent oxidation of fatty acids and phospholipids which are used by the epididymal spermatozoa as a substantial source of energy (19). Subsequently, a positive correla- tion between seminal plasma total carnitine with total sperm count and morphology has been reported, find- ings suggesting that the determination of seminal carni- tine levels may be a useful test in evaluation of male fer- tility (20), (21). Varicocele has been shown to impair the function of the accessory glands including the epi- didymis resulting in impaired semen quality (22). Such observations come in accordance with experimental data showing that the induction of varicocele causes impair- ment in the epididymal microenvironment resulting in reduced epididymal carnitine levels and subsequent hypoxia, increased apoptosis and possible subsequent infertility (23). Moreover, the beneficial effect of varico- celectomy on the epididymal function is reflected as an increase of epididymis-specific proteins such as alpha- glucosidase along with the improvement in semen parameters (24). An intriguing point is that seminal L- carnitine has been reported to be reduced in infertile patients with (low-grade) varicocele and normal semen parameters; the observation is meaningful as it shows that varicoceles might impair epididymal function and cause infertility even if this is not profound in conven- tional spermiogram, whereas LC could be used to unmask the underlying pathology and facilitate manage- ment (25). Secondly, the recent years the increased use of antioxidants as empirical treatment for several condi- 265Archivio Italiano di Urologia e Andrologia 2020; 92, 3 L-carnitene and varicocele Table 1. Summarized data of the studies. Scope Type of clinical trial Number of participants Main outcome/conclusions Comments Cavallini et al. (2004) Sofimajidpour et al. (2016) JT Seo et al. (2008) Pourmand et al. (2014) LC: L-carnitine; OAT: oligoasthenoazoospermia; VC: varicocele; SV: subclinical varicocele; * varicocele group. Placebo vs LC alone vs LC and cinnoxicam on the improvement of semen param- eters in infertile patients with idiopathic OAT and infertile patients with OAT and various grades of VC (including SV) Varicocelectomy vs LC alone on the improvement of semen parameters of infertile patients with varicocele of various clinical grades Observation vs varicocelectomy vs LC alone on infertile patients with SV Varicocelectomy alone vs Varicocelectomy plus adjuvant LC on improvement of semen parameters and DNA in infertile patients with varicocele Prospective/ randomized Prospective/ non-randomized (patient preference) Retrospective Prospective/(block) Randomized 195 patients into 3 groups * 62 patients into 2 groups 143 patients into 3 groups 100 patients into 2 groups Significant improvement in grades I-IV for drug combination but no treatment was effective in grade V No significant difference between groups Varicocelectomy outnum- bered LC monotherapy and observation in both semen parameters and pregnancy rates No statistically significant improvement in terms of parameters and DNA damage The higher the grade, the lower the benefit of drug therapy; combination group had increased pregnancy rates, but the contribution of grade is unknown Imbalance of grade contri- bution between groups as most patients at medical group had grade II and most patients at surgical group had grade III varicocele LC administration was better vs observation in terms of pregnancy rates but inferior to varicocelectomy Lower dose than used in other studies; trend in improvement of DNA dam- age; longer follow-up might be required (> 6 months) Archivio Italiano di Urologia e Andrologia 2020; 92, 3 G. Tsampoukas, M. Faisal Khan, A. Katsouri, W. Akhter, M. Moussa, K. Deliveliotis, A. Papatsoris, N. Buchholz 266 tions including male infertility has given birth to a phe- nomenon called “antioxidant paradox”, which is defined as the unresponsiveness of the body despite the admin- istration of large doses of dietary antioxidants (26). This paradoxical phenomenon along with the possibility of increased toxicity due to excessive use of antioxidants and the harming results of reductive stress have raised concerns for more accurate therapies and specific guide- lines in patients suffering from infertility (27). Therefore, we focused our search on LC alone or in dual combina- tion as the molecule has physiological significance and we reviewed its clinical relevance as therapeutic agent. The performance of LC in infertile patients with varicocele was reported in one randomized study and the authors concluded that the combination of the agent along with cinnoxicam was proven effective for subclinical and low- grade varicoceles in comparison to LC alone in terms of semen parameters; however, no treatment was efficient for high grades (13). If the varicocele grade affects the out- come of conservative treatment should be a matter of future research as the evidence is sparse. In a double- blind, placebo-controlled study, the combination of L- carnitine, fumarate, 5 acetyl- l- carnitine, fructose, CoQ10, vitamin C, zinc, folic acid and vitamin B12 for 6 months significantly improved the total sperm count and total and progressive motility in varicocele patients irrespective of grade; however, the pregnancy rate was not the end point in the study and cannot be assessed (28). In another study, 20 infertile patients with grade I varicocele were given multivitamins LC, vitamin C, coenzyme Q10, vita- min E, vitamin B9, vitamin B12, zinc, selenium and a sig- nificant improvement in sperm DNA quality and total sperm count was seen but other semen parameters were not affected (29). Patients with low-grade varicoceles might gain some benefit from the administration of LC in combination with other agents but future studies should explore the effect of conservative treatment on pregnancy rates especially in correlation with clinical grades. In terms of comparison with standard of care of varicoc- electomy, we identified two studies whom the conclu- sions should be examined carefully; none of the studies were randomized and one study had significant differ- ences between the compared groups (14). Nevertheless, in the latter study, treating grade II varicocele conserva- tively with LC had similar results with treating grade III varicocele surgically and the authors concluded that con- servative management could be an alternative to surgery in grade II varicoceles (14). In the study by Seo et al, treating subclinical varicocele with LC results in inferior pregnancy rates comparing to surgery but the perform- ance was better than the observation (15). The observa- tion comes is accordance with results from meta-analysis that subclinical varicocelectomy has some benefit in male infertility (30). Also, it seems that LC could be an alternative option in infertile patients with non-high- grade varicoceles, but the level of evidence is low. Last but not least, if LC is an alternative to surgery in low- grade disease needs to be clarified in future, prospective, randomized studies. Regarding the role of adjuvant LC in patients undergoing varicocelectomy one randomized study was identified which showed no clear benefit; however, there was a trend in favour of adjuvant treatment for motility and morphology (16). Similarly, other agents like ascorbic acid have been tested in the same manner with LC show- ing similar results (31). Although not fully relevant to humans, experimental data have shown that adjuvant treatment with LC may show significant benefit. In one study, Akdemir et al randomized 42 male rats into 7 groups comparing the effects of different varicocelecto- my techniques with or without adjuvant LC on sper- matogenesis and histopathological changes in testicular tissue (32). The authors observed that varicocelized rats treated with testicular non-artery sparing varicocelecto- my and adjuvant LC administration had significantly increased mRNA expression levels of factors inducing the spermatogenesis comparing to other groups; addi- tionally, in this group of patients the germ cells displayed almost total normalization in their cellular organisation (32). The discrepancy between the experimental studies and human cohorts might be associated with the nature of the condition as in experiments the varicocele is an acute phenomenon while in humans the varicocele rep- resents a chronic disease with long-standing effects on the germ epithelium. Although this field is still unex- plored, an effort to expand the efficacy of the surgery might be beneficial for some patients. A combined approach could help downgrade the indication in less invasive assisted-reproduction techniques, as this is the case with varicocelectomy in both clinical and subclini- cal forms (33). 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Correspondence Georgios Tsampoukas, MD scientific-Office@u-merge.com – tsampoukasg@gmail.com Noor Buchholz, MD noor.buchholz@gmail.com – U-merge scientific office Department of Urology, Princess Alexandra Hospital, Harlow (UK) U-merge scientific office 1, Menandrou Street, Athens 14561(Greece) Muhammad Faisal Khan, MD drfaisalkhan@gmail.com Department of Urology, North Devon Hospital, Barnstaple (UK) Antigoni Katsouri, MD a.katsr@gmail.com Department of Pharmacy, University of Patras, Patras (Greece) Waseem Akhter, MD waseemakhter@nhs.net Department of Urology, Princess Alexandra Hospital, Harlow (UK) Mohamad Moussa, MD mohamad.moussa@zhumc.org.lb Al Zahraa Hospital, University Medical Center, Lebanese University, Beirut (Lebanon) Konstantinos Deliveliotis, MD chdeliveli@gmail.com Athanasios Papatsoris, MD agpapatsoris@yahoo.gr 2nd Department of Urology, University Hospital of Athens, Athens (Greece)