Efficacy of antioxidant therapy on sperm quality measurements after varicocelectomy: A systematic review and meta-analysis

The epigenetic approach of varicocele: a focus on sperm DNA and m6A-RNA methylation

BACKGROUND

Varicocele is an abnormal dilation and torsion of the pampiniform venous plexus in the scrotum due to venous reflux, primarily affecting the left side. It affects 15% of men and is a prevalent contributor to male infertility. Varicocele is a complex disorder influenced by genetic, epigenetic, and environmental factors. Epigenetic modifications, which regulate genome activity independently of DNA or RNA sequences, may contribute to the development and severity of varicocele. These include DNA methylation, histone modifications, and RNA modifications like N6-methyladenosine (m6A). Irregularities in DNA and m6A-RNA methylation during spermatogenesis can cause gene expression abnormalities, DNA damage, and decreased fertility in varicocele patients.

OBJECTIVE AND RATIONALE

The review aims to comprehensively understand the underlying mechanisms of varicocele, a condition that can significantly impact male fertility. By exploring the role of methylation modifications, specifically DNA and m6A-RNA methylation, the review aims to synthesize evidence from basic, preclinical, and clinical research to expand the existing knowledge on this subject. The ultimate goal is to identify potential avenues for developing targeted treatments that can effectively improve varicocele and ultimately increase sperm quality in affected individuals.

SEARCH METHODS

A thorough investigation of the scientific literature was conducted through searches in PubMed, Google Scholar, and Science Direct databases until May 2024. All studies investigating the relationship between DNA and m6A-RNA methylation and male infertility, particularly varicocele were reviewed, and the most pertinent reports were included. Keywords such as varicocele, epigenetics, DNA methylation, m6A-RNA methylation, hypermethylation, hypomethylation, spermatozoa, semen parameters, spermatogenesis, and male infertility were used during the literature search, either individually or in combination.

OUTCOMES

The sperm has a specialized morphology essential for successful fertilization, and its epigenome is unique, potentially playing a key role in embryogenesis. Sperm DNA and RNA methylation, major epigenetic marks, regulate the expression of testicular genes crucial for normal spermatogenesis. This review explores the role of DNA and m6A-RNA methylation, in responding to oxidative stress and how various nutrients influence their function in varicocele condition. Evidence suggests a potential link between varicocele and aberrant DNA/m6A-RNA methylation patterns, especially hypomethylation, but the body of evidence is still limited. Further studies are needed to understand how abnormal expression of DNA/m6A-RNA methylation regulators affects testicular gene expression. Thus, analyzing sperm DNA 5mC/5hmC levels and m6A-RNA methylation regulators may reveal spermatogenesis defects and predict reproductive outcomes.

WIDER IMPLICATIONS

Nutri-epigenomics is an emerging field that could enhance the knowledge and management of diseases with unpredictable risks and consequences, even among individuals with similar lifestyles, by elucidating the influence of nutrition on DNA/m6A-RNA methylation through one-carbon metabolism. However, the importance of one-carbon metabolism to varicocele is not well-recognized. Health status and diet influence one-carbon metabolism and its associated DNA/m6A-RNA methylation modification. Future research should identify optimal methylation patterns that promote health and investigate modulating one-carbon metabolism to achieve this. Furthermore, additional studies are necessary to develop personalized dietary strategies through clinical and longitudinal research. However, a research gap exists on dietary interventions utilizing epigenetics as a therapeutic method for treating varicocele.

REGISTRATION NUMBER

Not applicable.

Effect of biotin supplementation and swimming training on oxidative stress and testicular function in male rats

Oxidative stress (OS) affects testicular function and is a significant cause of sperm cell dysfunction in males. The development of male infertility is closely linked to a sedentary lifestyle and diet. This study aimed to characterize the protective effects of biotin supplementation (BS) and swimming training (ST) on OS markers in the reproductive system of male rats. Forty male rats (200-250 g) were randomly assigned to four groups (n = 10 per group) and treated for 28 days as follows: control, BS (this group received BS through oral gavage), ST, and BS + ST groups. Our results showed that glutathione (GSH) levels significantly increased in the BS, ST (p < 0.05), and BS + ST (p < 0.01) groups, whereas malondialdehyde (MDA) levels significantly decreased in these experimental groups (p < 0.05 for all). Additionally, compared to the controls, there was a significant increase (p < 0.05) in blood levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone (T), and high-density lipoprotein (HDL) in the BS and ST groups evidenced by a decrease in the levels of other biochemical parameters (cholesterol (CHO), triglyceride (TG), low-density lipoprotein (LDL), alanine transaminase (ALT), aspartate transaminase (AST), and alkaline phosphatase (ALP)). According to histological examination, the BS, ST, and BS + ST groups showed an improvement compared to the control group. In conclusion, BS had positive effects on biochemical parameters and antioxidant activity, and BS along with ST improved testicular function in male rats.

The impact of antioxidants on antioxidant capacity, DNA fragmentation, and chromatin quality in subfertile men: a randomized clinical trial study

OBJECTIVE

This randomized clinical trial study aims to investigate the effects of antioxidant food supplementation on the total antioxidant capacity of seminal plasma, sperm DNA fragmentation, sperm chromatin quality, and semen parameters.

METHODS

In this study, a total of 48 subfertile men with moderate physical activity were included. Group 1 was recommended to use the antioxidant supplements, while antioxidant food supplements were not given to Group 2. Total antioxidant capacity, sperm DNA fragmentation, sperm chromatin structure, hormone levels, physical activities, and semen parameters were evaluated before and after treatment. Total antioxidant capacity, sperm DNA fragmentation, and sperm chromatin structure were assessed using ELISA, transferase dUTP nick end labeling, and aniline blue staining, respectively.

RESULTS

Sperm DNA fragmentation (p=0.003) and histone/protamine ratio (p<0.001) were significantly decreased in the patients receiving antioxidant treatment. There was no statistical difference in the total antioxidant capacity values of the post-treatment groups.

CONCLUSION

Antioxidant therapy seems to improve sperm DNA fragmentation and histone/protamine ratios in subfertile patients.

CLINICAL TRIAL REGISTRATION NUMBER

NCT06042738.

Current treatment for male infertility: an umbrella review of systematic reviews and meta-analyses

ABSTRACT

This umbrella review aimed to summarize and provide a general evaluation of the effectiveness of current treatments for male infertility and assess the quality of evidence and possible biases. An umbrella review of systematic reviews and meta-analyses available in PubMed, Web of Science, and Scopus, covering studies published up to October 2023, was conducted. Sperm concentration, morphology, and motility were used as endpoints to evaluate the effectiveness of the treatments. Of 2998 studies, 18 published meta-analyses were extracted, yielding 90 summary effects on sperm concentration ( n = 36), sperm morphology ( n = 26), and sperm motility ( n = 28) on 28 interventions. None of the meta-analyses were classified as having low methodological quality, whereas 12 (66.7%) and 6 (33.3%) had high and moderate quality, respectively. Of the 90 summary effects, none were rated high-evidence quality, whereas 53.3% ( n = 48), 25.6% ( n = 23), and 21.1% ( n = 19) were rated moderate, low, and very low, respectively. Significant improvements in sperm concentration, morphology, and motility were observed with pharmacological interventions (N-acetyl-cysteine, antioxidant therapy, aromatase inhibitors, selective estrogen receptor modulators, hormones, supplements, and alpha-lipoic acid) and nonpharmacological interventions (varicocele repair and redo varicocelectomy). In addition, vitamin supplementation had no significant positive effects on sperm concentration, motility, or morphology. Treatments for male infertility are increasingly diverse; however, the current evidence is poor because of the limited number of patients. Further well-designed studies on single treatment and high-quality meta-analysis of intertreatment comparisons are recommended.

The effect of astaxanthin after varicocele surgery on antioxidant status and semen quality in infertile men: A triple-blind randomized clinical trial

Varicocele (VC) is widely recognized as a prevalent etiological factor contributing to male infertility. It has been established that the generation of reactive oxygen species (ROS) plays a significant role in the progression and development of VC. Antioxidants may regulate ROS levels in these patients. Astaxanthin (ASX) is a carotenoid compound with notable antioxidant and anti-inflammatory characteristics. The current study postulated that the administration of ASX following varicocelectomy (VCT) could potentially enhance antioxidant status and semen quality in these patients. A total of 40 infertile males with clinical VC and abnormal semen analyses were randomly assigned to take part in the current trial. For 3 months following surgery, the intervention group took ASX (6 mg/day) while the control group received a placebo. After intervention, semen parameters, antioxidant status, and pro-inflammatory cytokines were compared between the two groups. Regarding semen parameters, antioxidant treatment led to a significant improvement in total and progressive motility in the treatment group (p < 0.05). Additionally, ASX led to a considerable increase in the expression levels of NRF2, Keap1, SOD2, SOD3, and BCL2, though the enhancement in the expression level of SOD3 was not statistically significant (p > .05). However, ASX significantly decreased the BAX expression level (p < .05). Even though the level of total antioxidant capacity (TAC) of seminal fluid (SF) increased significantly in the treatment group (p < .05), the level of total oxidative stress (TOS) in SF did not differ substantially between treatment and control groups (p > .05). Based on inflammatory factors in SF, ASX led to a considerable reduction in levels of TNF-α, IL-1β, and IL-6 (p < .05). Our findings demonstrated that ASX treatment provides an important contribution to VCT outcomes by modulating antioxidant status and pro-inflammatory cytokines. Our results indicated that ASX may be beneficial as an adjuvant therapy for infertile men following VCT.

Antioxidants for male infertility: therapeutic scheme and indications. A retrospective single-center real-life study

BACKGROUND

This single-center real-life study was conducted to evaluate the most effective combination of nutraceuticals and the most appropriate indications for the treatment of male infertile patients.

METHODS

Infertile patients aged 20-55 years were treated with a combination of antioxidants (Androlen®; Enfarma, Misterbianco, Catania, Italy) (group A), with Androlen® (Enfarma) and a mixture of fibrinolytic molecules (Lenidase®, Enfarma) (group B), or Androlen® (Enfarma) and other molecules different from those used for the patients of the group B (group C). Patients were also subdivided according to the presence of varicocele, mild testicular hypotrophy, idiopathic infertility, and chronic male accessory gland infection.

RESULTS

Forty-three patients were enrolled. In the overall analysis, only progressive motility significantly improved after therapy. Subgroup analysis showed a significant increase in progressive motility, total motile sperm count (TMSC), and in the percentage of alive spermatozoa after treatment in the group A. Progressive motility improved significantly in patients with varicocele, while the TMSC in patients with varicocele and those with idiopathic infertility. The percentage of alive spermatozoa increased in patients with testicular hypotrophy.

CONCLUSIONS

Treatment with antioxidants increased progressive sperm motility, especially in patients with varicocele or idiopathic infertility.

Add-on effects of oral tocopherol supplementation to surgical varicocelectomy on the outcome of assisted reproductive technology: a single-center pilot study report

Introduction

Varicocelectomy is well known to improve the pregnancy outcome of patients with clinical varicoceles in assisted reproductive technologies as well as spontaneous conception. Therefore, this study aimed to evaluate the additional effects of oral antioxidant therapy after varicocelectomy on the pregnancy outcome in the assisted reproductive technology setting.

Methods

This study was a retrospective cohort study. The subjects were couples among whom the male partner had undergone varicocelectomy and was scheduled for subsequent assisted reproductive technology. Pregnancy outcomes were followed retrospectively in 62 couples with male partners who received tocopherol (antioxidant group) and 37 couples who did not (control group). The tocopherol and control groups were assigned dependent on the decision of the physician in charge and the patient's request. The clinical pregnancy rates per couple and embryo transfer, time to pregnancy, and the number of cycles during transfer to pregnancy were evaluated.

Results

No significant differences were observed in the pregnancy rate per couple (antioxidant group 70.9% vs. control group 64.9%, P = 0.55) and per embryo transfer (50.4% vs. 39.6%, P = 0.22). Regarding the time to event analyzed by adjusted restricted mean survival time, the mean time to pregnancy was significantly shorter in the antioxidant (tocopherol) group (14.2 vs. 17.4 months, P = 0.025). No significant difference was observed in the embryo transfer cycle to pregnancy (mean embryo transfer cycles: 2.6 vs. 3.0, P = 0.238).

Conclusions

Additional oral tocopherol nicotinate as antioxidant therapy after varicocelectomy was shown to shorten the time to pregnancy. It is recommended that add-on effects be tested in more well-designed randomized controlled trials to examine whether it improves assisted reproductive outcomes.

ESHRE Add-ons working group, Lundin K, Bentzen JG, Bozdag G, Ebner T, Harper J, Le Clef N, Moffett A, Norcross S, Polyzos NP, Rautakallio-Hokkanen S, Sfontouris I, Sermon K, Vermeulen N, Pinborg A. Good practice recommendations on add-ons in reproductive medicine†

STUDY QUESTION

Which add-ons are safe and effective to be used in ART treatment?

SUMMARY ANSWER

Forty-two recommendations were formulated on the use of add-ons in the diagnosis of fertility problems, the IVF laboratory and clinical management of IVF treatment.

WHAT IS KNOWN ALREADY

The innovative nature of ART combined with the extremely high motivation of the patients has opened the door to the wide application of what has become known as 'add-ons' in reproductive medicine. These supplementary options are available to patients in addition to standard fertility procedures, typically incurring an additional cost. A diverse array of supplementary options is made available, encompassing tests, drugs, equipment, complementary or alternative therapies, laboratory procedures, and surgical interventions. These options share the common aim of stating to enhance pregnancy or live birth rates, mitigate the risk of miscarriage, or expedite the time to achieving pregnancy.

STUDY DESIGN, SIZE, DURATION

ESHRE aimed to develop clinically relevant and evidence-based recommendations focusing on the safety and efficacy of add-ons currently used in fertility procedures in order to improve the quality of care for patients with infertility.

PARTICIPANTS/MATERIALS, SETTING, METHODS

ESHRE appointed a European multidisciplinary working group consisting of practising clinicians, embryologists, and researchers who have demonstrated leadership and expertise in the care and research of infertility. Patient representatives were included in the working group. To ensure that the guidelines are evidence-based, the literature identified from a systematic search was reviewed and critically appraised. In the absence of any clear scientific evidence, recommendations were based on the professional experience and consensus of the working group. The guidelines are thus based on the best available evidence and expert agreement. Prior to publication, the guidelines were reviewed by 46 independent international reviewers. A total of 272 comments were received and incorporated where relevant.

MAIN RESULTS AND THE ROLE OF CHANCE

The multidisciplinary working group formulated 42 recommendations in three sections; diagnosis and diagnostic tests, laboratory tests and interventions, and clinical management.

LIMITATIONS, REASONS FOR CAUTION

Of the 42 recommendations, none could be based on high-quality evidence and only four could be based on moderate-quality evidence, implicating that 95% of the recommendations are supported only by low-quality randomized controlled trials, observational data, professional experience, or consensus of the development group.

WIDER IMPLICATIONS OF THE FINDINGS

These guidelines offer valuable direction for healthcare professionals who are responsible for the care of patients undergoing ART treatment for infertility. Their purpose is to promote safe and effective ART treatment, enabling patients to make informed decisions based on realistic expectations. The guidelines aim to ensure that patients are fully informed about the various treatment options available to them and the likelihood of any additional treatment or test to improve the chance of achieving a live birth.

STUDY FUNDING/COMPETING INTEREST(S)

All costs relating to the development process were covered from ESHRE funds. There was no external funding of the development process or manuscript production. K.L. reports speakers fees from Merck and was part of a research study by Vitrolife (unpaid). T.E. reports consulting fees from Gynemed, speakers fees from Gynemed and is part of the scientific advisory board of Hamilton Thorne. N.P.P. reports grants from Merck Serono, Ferring Pharmaceutical, Theramex, Gedeon Richter, Organon, Roche, IBSA and Besins Healthcare, speakers fees from Merck Serono, Ferring Pharmaceutical, Theramex, Gedeon Richter, Organon, Roche, IBSA and Besins Healthcare. S.R.H. declares being managing director of Fertility Europe, a not-for-profit organization receiving financial support from ESHRE. I.S. is a scientific advisor for and has stock options from Alife Health, is co-founder of IVFvision LTD (unpaid) and received speakers' fee from the 2023 ART Young Leader Prestige workshop in China. A.P. reports grants from Gedeon Richter, Ferring Pharmaceuticals and Merck A/S, consulting fees from Preglem, Novo Nordisk, Ferring Pharmaceuticals, Gedeon Richter, Cryos and Merck A/S, speakers fees from Gedeon Richter, Ferring Pharmaceuticals, Merck A/S, Theramex and Organon, travel fees from Gedeon Richter. The other authors disclosed no conflicts of interest.

DISCLAIMER

This Good Practice Recommendations (GPRs) document represents the views of ESHRE, which are the result of consensus between the relevant ESHRE stakeholders and are based on the scientific evidence available at the time of preparation.ESHRE GPRs should be used for information and educational purposes. They should not be interpreted as setting a standard of care or bedeemedinclusive of all proper methods of care, or be exclusive of other methods of care reasonably directed to obtaining the same results.Theydo not replace the need for application of clinical judgement to each individual presentation, or variations based on locality and facility type.Furthermore, ESHRE GPRs do not constitute or imply the endorsement, or favouring, of any of the included technologies by ESHRE.

[Varicocele and male infertility]

BACKGROUND

Varicocele is the most common correctable cause of male infertility. It was the subject of recent Association française d'urologie (AFU) Comité d'andrologie et de médecine sexuelle (CAMS) recommendations. Since then, the literature has provided additional information. This review will comprehensively reassess current indications for the treatment of varicocele, and revisit contemporary issues in the light of current advances.

METHODS

Update of the literature search carried out as part of the CAMS recommendations for the period between 2020 and 2023.

RESULTS

Microsurgical sub-inguinal varicocelectomy remains the surgical treatment of choice for infertile men with clinical varicocele and abnormal sperm parameters. It offers recurrence rates of less than 4%. It significantly improves both natural and in vitro fertilization live birth and pregnancy rates, as well as sperm count, total and progressive motility, morphology and DNA fragmentation rates. All in all, it modifies the MPA strategy in around one in two cases. Varicocele grade and bilaterality are predictive of improved sperm parameters and pregnancy rate. Treatment of subclinical varicocele is not recommended. Complications are rare, notably hydroceles (0.5%), unilateral testicular atrophy due to arterial damage (1/1000), hematomas, delayed healing and postoperative pain. Retrograde embolization is an alternative to surgery.

CONCLUSION

Whenever possible, the urologist should present and discuss treatment options for varicocele with the MPA team and the patient, taking a personalized approach.

Oxidative Stress and Male Infertility: The Protective Role of Antioxidants

Oxidative stress is a significant factor in male infertility, compromising sperm function and overall reproductive health. As male infertility garners increasing attention, effective therapeutic interventions become paramount. This review investigates the therapeutic role of antioxidants in addressing male infertility. A detailed examination was conducted on antioxidants such as vitamin C, E, B12, D, coenzyme Q10, zinc, folic acid, selenium, l-carnitine, l-arginine, inositols, and alpha-lipoic acid. This analysis examines the methodologies, outcomes, and constraints of current clinical studies. Antioxidants show notable potential in counteracting the negative effects of oxidative stress on sperm. Based on the evidence, these antioxidants, individually or synergistically, can enhance sperm health and reproductive outcomes. However, certain limitations in the studies call for careful interpretation. Antioxidants are integral in tackling male infertility attributed to oxidative stress. The current findings underscore their therapeutic value, yet there's a pressing need for deeper, comprehensive research. Future studies should focus on refining dosage guidelines, identifying potential side effects, and discerning the most efficacious antioxidant combinations for male infertility solutions.

Effect of Varicocelectomy on Serum Follicle-Stimulating Hormone and Testosterone; The Interrelationship Between Hormonal Variables

Purpose

The present study was conducted to analyze the effect of varicocelectomy on serum follicle-stimulating hormone (FSH) and testosterone. The interrelationship between seminal and hormonal variables is also investigated.

Patients and Methods

A prospective cohort study was conducted on patients of the urology clinic from 2012 to 2017. The study was conducted in the Security Forces Hospital, in Riyadh, Saudi Arabia. Infertile patients who had already undergone the FSH examination and testosterone twice were included in the study. Statistical Package for Social Sciences (SPSS) version 21.0 was used to analyze the data.

Results

A total of 186 patients were studied which reveals that the age group of 21-30 years was higher than other age groups 80 (43%), micro varicocelectomy was performed in 138 (74%) of patients and 79 (47%) patients had one-year infertility. The study assessed the effect of varicocelectomy on sperm count and motility serum FSH, testosterone, luteinizing hormone (LH), and prolactin, and it was found that none of the variables showed significant association after varicocelectomy, except for luteinizing hormone (P-value = 0.014). Testosterone levels in patients who had FSH ≤10 were also evaluated and it was found that the level of testosterone was increased with a decreased level of FSH (P-value = 0.005).

Conclusion

It was concluded from our results that after varicocelectomy, those patients who had FSH levels ≤10 were found to have increased testosterone levels. LH was also found to be significant; however, other hormones were not found to be significant. This may occur due to the reason that we have the majority of the participants in the age group 21-30. Further prospective studies are needed to evaluate the association with ample sample size.

Protective effects of melatonin against the toxic effects of environmental pollutants and heavy metals on testicular tissue: A systematic review and meta-analysis of animal studies

BACKGROUND

Environmental pollution and infertility are two modern global challenges that agonize personal and public health. The causal relationship between these two deserves scientific efforts to intervene. It is believed that melatonin maintains antioxidant properties and may be utilized to protect the testicular tissue from oxidant effects caused by toxic materials.

METHODS

A systematic literature search was conducted in PubMed, Scopus, and Web of Science to identify the animal trial studies that evaluated melatonin therapy's effects on rodents' testicular tissue against oxidative stress caused by heavy metal and non-heavy metal environmental pollutants. Data were pooled, and standardized mean difference and 95% confidence intervals were estimated using the random-effect model. Also, the risk of bias was assessed using the Systematic Review Centre for Laboratory animal Experimentation (SYRCLE) tool. (PROSPERO: CRD42022369872).

RESULTS

Out of 10039 records, 38 studies were eligible for the review, of which 31 were included in the meta-analysis. Most of them showed beneficial effects of melatonin therapy on testicular tissue histopathology. [20 toxic materials were evaluated in this review, including arsenic, lead, hexavalent chromium, cadmium, potassium dichromate, sodium fluoride, cigarette smoke, formaldehyde, carbon tetrachloride (CCl4), 2-Bromopropane, bisphenol A, thioacetamide, bisphenol S, ochratoxin A, nicotine, diazinon, Bis(2-ethylhexyl) phthalate (DEHP), Chlorpyrifos (CPF), nonylphenol, and acetamiprid.] The pooled results showed that melatonin therapy increased sperm count, motility, viability and body and testicular weights, germinal epithelial height, Johnsen's biopsy score, epididymis weight, seminiferous tubular diameter, serum testosterone, and luteinizing hormone levels, testicular tissue Malondialdehyde, glutathione peroxidase, superoxide dismutase, and glutathione levels. On the other hand, abnormal sperm morphology, apoptotic index, and testicular tissue nitric oxide were lower in the melatonin therapy arms. The included studies presented a high risk of bias in most SYRCLE domains.

CONCLUSION

In conclusion, our study demonstrated amelioration of testicular histopathological characteristics, reproductive hormonal panel, and tissue markers of oxidative stress. Melatonin deserves scientific attention as a potential therapeutic agent for male infertility.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/PROSPERO, identifier CRD42022369872.

Improvement in sperm quality by oral antioxidant supplementation in infertile men with varicocele who have not undergone surgical repair: Systematic review and meta-analysis

The aim of this systematic review and meta-analysis was to assess whether oral antioxidant supplementation improves sperm quality in men with infertility and varicocele (VCL) who have not undergone surgical repair. In men with infertility and VCL who had not undergone surgical repair oral antioxidant supplementation significantly increased sperm concentration (WMD +5.86 × 10⁶ /ml 95% CI: +1.47 to +10.24, p < 0.01; random effects model, six studies, 213 patients), total motility (WMD + 3.76%, 95% CI: +0.18 to +7.34, p = 0.04; random effects model, three studies, 93 patients), progressive motility (WMD + 6.38%, 95% CI: +3.04 to +9.71, p < 0.01; random effects model, three studies, 84 patients) and seminal volume (WMD +0.55 ml, 95%CI: +0.06 to +1.04, p = 0.03; random effects model, four studies, 120 patients). On the other hand, no significance difference was observed in sperm morphology (WMD +3.89%, 95% CI: -0.14 to +7.92, p = 0.06; random effects model, five studies, 187 patients). In conclusion, limited evidence suggests that the use of oral antioxidants in men with infertility and VCL, who have not undergone surgical repair improves their seminal volume, sperm concentration, total and progressive motility.

Antioxidants for male subfertility

BACKGROUND

The inability to have children affects 10% to 15% of couples worldwide. A male factor is estimated to account for up to half of the infertility cases with between 25% to 87% of male subfertility considered to be due to the effect of oxidative stress. Oral supplementation with antioxidants is thought to improve sperm quality by reducing oxidative damage. Antioxidants are widely available and inexpensive when compared to other fertility treatments, however most antioxidants are uncontrolled by regulation and the evidence for their effectiveness is uncertain. We compared the benefits and risks of different antioxidants used for male subfertility.

OBJECTIVES

To evaluate the effectiveness and safety of supplementary oral antioxidants in subfertile men.

SEARCH METHODS

The Cochrane Gynaecology and Fertility (CGF) Group trials register, CENTRAL, MEDLINE, Embase, PsycINFO, AMED, and two trial registers were searched on 15 February 2021, together with reference checking and contact with experts in the field to identify additional trials.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared any type, dose or combination of oral antioxidant supplement with placebo, no treatment, or treatment with another antioxidant, among subfertile men of a couple attending a reproductive clinic. We excluded studies comparing antioxidants with fertility drugs alone and studies that included men with idiopathic infertility and normal semen parameters or fertile men attending a fertility clinic because of female partner infertility.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures recommended by Cochrane. The primary review outcome was live birth. Clinical pregnancy, adverse events and sperm parameters were secondary outcomes.

MAIN RESULTS

We included 90 studies with a total population of 10,303 subfertile men, aged between 18 and 65 years, part of a couple who had been referred to a fertility clinic and some of whom were undergoing medically assisted reproduction (MAR). Investigators compared and combined 20 different oral antioxidants. The evidence was of 'low' to 'very low' certainty: the main limitation was that out of the 67 included studies in the meta-analysis only 20 studies reported clinical pregnancy, and of those 12 reported on live birth. The evidence is current up to February 2021. Live birth: antioxidants may lead to increased live birth rates (odds ratio (OR) 1.43, 95% confidence interval (CI) 1.07 to 1.91, P = 0.02, 12 RCTs, 1283 men, I2 = 44%, very low-certainty evidence). Results in the studies contributing to the analysis of live birth rate suggest that if the baseline chance of live birth following placebo or no treatment is assumed to be 16%, the chance following the use of antioxidants is estimated to be between 17% and 27%. However, this result was based on only 246 live births from 1283 couples in 12 small or medium-sized studies. When studies at high risk of bias were removed from the analysis, there was no evidence of increased live birth (Peto OR 1.22, 95% CI 0.85 to 1.75, 827 men, 8 RCTs, P = 0.27, I2 = 32%). Clinical pregnancy rate: antioxidants may lead to increased clinical pregnancy rates (OR 1.89, 95% CI 1.45 to 2.47, P < 0.00001, 20 RCTs, 1706 men, I2 = 3%, low-certainty evidence) compared with placebo or no treatment. This suggests that, in the studies contributing to the analysis of clinical pregnancy, if the baseline chance of clinical pregnancy following placebo or no treatment is assumed to be 15%, the chance following the use of antioxidants is estimated to be between 20% and 30%. This result was based on 327 clinical pregnancies from 1706 couples in 20 small studies. Adverse events Miscarriage: only six studies reported on this outcome and the event rate was very low. No evidence of a difference in miscarriage rate was found between the antioxidant and placebo or no treatment group (OR 1.46, 95% CI 0.75 to 2.83, P = 0.27, 6 RCTs, 664 men, I2 = 35%, very low-certainty evidence). The findings suggest that in a population of subfertile couples, with male factor infertility, with an expected miscarriage rate of 5%, the risk of miscarriage following the use of an antioxidant would be between 4% and 13%. Gastrointestinal: antioxidants may lead to an increase in mild gastrointestinal discomfort when compared with placebo or no treatment (OR 2.70, 95% CI 1.46 to 4.99, P = 0.002, 16 RCTs, 1355 men, I2 = 40%, low-certainty evidence). This suggests that if the chance of gastrointestinal discomfort following placebo or no treatment is assumed to be 2%, the chance following the use of antioxidants is estimated to be between 2% and 7%. However, this result was based on a low event rate of 46 out of 1355 men in 16 small or medium-sized studies, and the certainty of the evidence was rated low and heterogeneity was high. We were unable to draw conclusions from the antioxidant versus antioxidant comparison as insufficient studies compared the same interventions.

AUTHORS' CONCLUSIONS

In this review, there is very low-certainty evidence from 12 small or medium-sized randomised controlled trials suggesting that antioxidant supplementation in subfertile males may improve live birth rates for couples attending fertility clinics. Low-certainty evidence suggests that clinical pregnancy rates may increase. There is no evidence of increased risk of miscarriage, however antioxidants may give more mild gastrointestinal discomfort, based on very low-certainty evidence. Subfertile couples should be advised that overall, the current evidence is inconclusive based on serious risk of bias due to poor reporting of methods of randomisation, failure to report on the clinical outcomes live birth rate and clinical pregnancy, often unclear or even high attrition, and also imprecision due to often low event rates and small overall sample sizes. Further large well-designed randomised placebo-controlled trials studying infertile men and reporting on pregnancy and live births are still required to clarify the exact role of antioxidants.

Antioxidants in male infertility

OBJECTIVE

To study the effect of three antioxidants viz. selenium, carnitine and coenzyme Q10, alone or in combination, on both semen parameters and pregnancy rates in couples with male factor infertility.

METHODS

Using PRISMA guidelines, a systematic search was performed of the PubMed®, Scopus®, EMBASE®, and Web of Science® databases for randomized studies comparing selenium, carnitine or coenzyme Q10 with placebo in the treatment of male infertility and reporting semen and pregnancy outcomes.

RESULTS

3304 studies were screened of which 20 were included. The study protocol was registered with PROSPERO (CRD42020210284). Pregnancy rate in the treatment group (69/426, 16.2%) was not different from the placebo (45/401, 11.2%) (p=0.05). Treatment group showed higher motility [mean difference 5.05, 95% CI (2.77, 7.34), p=<0.0001], progressive motility [mean difference 5.72, 95% CI (2.77, 8.66), p=0.0001], sperm concentration [mean difference 6.58, 95% CI (3.22, 9.93), p=0.0001] than placebo.

CONCLUSIONS

Although antioxidants and their combinations are associated with improvement in sperm concentration, motility, and semen volume, the differences are small. There is no difference in pregnancy rates between patients receiving selenium, carnitine, and coenzyme Q10, or placebo. The quality of studies is poor, limiting the level of evidence.

Effect of keishibukuryogan combined with tocopherol nicotinate on sperm parameters in patients with a varicocele

OBJECTIVE

To evaluate the efficacy of keishibukuryogan, a traditional Kampo formula known to be an anti-Oketsu (impaired microcirculation and non-physiological blood congestion) drug, in combination with an anti-oxidant for the treatment of varicoceles.

METHODS

We retrospectively analyzed 119 patients with palpable and subclinical varicoceles who were treated with 7.5 g/day of keishibukuryogan and 600 mg/day of tocopherol nicotinate. Their motile sperm concentrations at the start of medication and after 3 months were compared. As a subgroup analysis, a comparison test was carried out between patients with a high-grade varicocele and those with a low-grade varicocele.

RESULTS

The mean age of the study patients was 35.6 years. Among them, 17, 41, 44 and 17 had subclinical, grade 1, grade 2 and grade 3 varicoceles, respectively. Overall, the differences in motile sperm concentration (millions/mL) before and after treatment were not significant (median 0.58, 95% confidence interval -0.12 to 1.56; P = 0.115). The results of the subgroup analysis showed that the motile sperm concentration in patients with a low-grade varicocele significantly increased (median 1.21, 95% confidence interval 0.45-2.47; P = 0.024); however, no significant improvements were seen in patients with a high-grade varicocele.

CONCLUSIONS

The results of the present study showed that the combination of keishibukuryogan and an anti-oxidant had a limited effect on varicoceles, but they suggest that it is effective for the treatment of low-grade varicoceles.

Effect of curcumin, and nano-curcumin on sperm function in varicocele rat model

Varicocele is one of the most important causes of infertility in men which gradually leads to testicular dysfunction. Testicular heat stress-induced oxidative stress is considered the main cause of pathology in these individuals. In this study, the effects of curcumin and nano-curcumin, as natural antioxidants, were investigated on spermatogenesis and sperm function in varicocele-induced rats. Seventy Wistar rats were randomly divided into seven groups; sham, control, varicocele, varicocele + curcumin 50 mg, varicocele + curcumin 100 mg, varicocele + nano-curcumin 4 mg and varicocele + nano-curcumin 8 mg. After 2 months of antioxidant therapy, all the rats were sacrificed. The results demonstrated that the mean sperm concentration and motility were significantly lower while the mean of abnormal morphology, lipid peroxidation, intracytoplasmic ROS and DNA damage was significantly higher in varicocelised rats compared to control and sham groups (p < .05). Both doses of curcumin and also nano-curcumin were significantly effective in improving the aforementioned parameters except for abnormal sperm morphology, and motility where nano-curcumin (4 mg) was significantly more effective than other groups (p < .05). The results of the current study suggest the application of nano-curcumin is more preferable to curcumin in infertile individuals with varicocele.

The Effect of Antioxidant Supplementation on Operated or Non-Operated Varicocele-Associated Infertility: A Systematic Review and Meta-Analysis

In patients with varicocele-associated infertility, the effect of antioxidant supplementation on fertility is unknown. We performed a systematic review and meta-analysis to explore their role in patients with operated or non-operated varicocele. We searched major databases and sources of grey literature until May 2021 (PROSPERO: CRD42021248195). We included 14 studies (980 individuals) in the systematic review. Of the 14 studies, 2 explored the effect of antioxidant supplementation in patients with non-operated varicocele, 1 compared antioxidants versus surgical repair of varicocele, while 11 explored antioxidants after surgical repair of varicocele and were also included in the meta-analysis. Regarding pregnancy rates, no significant differences were demonstrated after treatment with antioxidants versus no treatment at three (OR: 2.28, 95% CI: 0.7-7.48) and six months (OR: 1.88, 95% CI: 0.62-5.72). Accordingly, contradictory findings were reported in sperm concentration, morphology, and motility, as well as DNA fragmentation. Our findings indicate that antioxidant supplementation does not improve pregnancy rates and semen parameters in patients with varicocele-associated infertility, in the absence of previous screening for oxidative stress. Based on the previous notion, most included studies also raised methodological concerns. Therefore, definitive conclusions about the efficacy of antioxidant supplementation in this setting cannot be drawn and further research on the field is mandatory.

Utility of Antioxidants in the Treatment of Male Infertility: Clinical Guidelines Based on a Systematic Review and Analysis of Evidence

It is widely accepted that oxidative stress plays an important role in the pathophysiology of male infertility and that antioxidants could have a significant role in the treatment of male infertility. The main objectives of this study are: 1) to systematically review the current evidence for the utility of antioxidants in the treatment of male infertility; and 2) propose evidence-based clinical guidelines for the use of antioxidants in the treatment of male infertility. A systematic review of the available clinical evidence was performed, with articles published on Scopus being manually screened. Data extracted included the type of antioxidant used, the clinical conditions under investigation, the evaluation of semen parameters and reproductive outcomes. The adherence to the Cambridge Quality Checklist, Cochrane Risk of Bias for randomized controlled trials (RCTs), CONSORT guidelines and JADAD score were analyzed for each included study. Further, we provided a Strength Weakness Opportunity Threat (SWOT) analysis to analyze the current and future value of antioxidants in male infertility. Of the 1,978 articles identified, 97 articles were included in the study. Of these, 52 (53.6%) were uncontrolled (open label), 12 (12.4%) unblinded RCTs, and 33 (34.0%) blinded RCTs, whereas 44 (45.4%) articles tested individual antioxidants, 31 (32.0%) a combination of several products in variable dosages, and 22 (22.6%) registered antioxidant products. Based on the published evidence, we 1) critically examined the necessity of additional double-blind, randomized, placebo-controlled trials, and 2) proposed updated evidence-based clinical guidelines for antioxidant therapy in male infertility. The current systematic review on antioxidants and male infertility clearly shows that antioxidant supplementation improves semen parameters. In addition, it provides the indications for antioxidant treatment in specific clinical conditions, including varicocele, unexplained and idiopathic male infertility, as well as in cases of altered semen quality.