Correlation between methylenetetrahydrofolate reductase gene polymorphism and oligoasthenospermia and the effects of folic acid supplementation on semen quality

MTHFR C677T、MTHFR A1298C、MTRR A66G and MTR A2756G polymorphisms and male infertility risk: a systematic review and meta-analysis

BACKGROUND

Epidemiological studies have reported that polymorphisms of folate-metabolizing genes have a significant impact on male infertility. However, the results of published studies have come to different conclusions.

OBJECTIVE

To determine an association between folate-metabolizing gene polymorphisms and the risk of male infertility.

METHODS

The meta-analysis was conducted according to the PRISMA 2020 statement. The protocol was registered with PROSPERO (CRD42023412251). Studies were searched from PubMed, Google Scholar, Embase, Scopus, and the Cochrane Library up to 24st October2023. Articles that satisfied the inclusion criteria were evaluated for their quality using the Newcastle-Ottawa Scale. Data were extracted from the eligible studies and were analyzed for pooled up odds ratio (OR) with 95% confidence interval (CI). Meta-analysis was conducted using STATA 12.

RESULTS

Forty-six case-control studies were included in the meta-analysis which comprised 20,639 participants. The pooled analysis revealed that the MTHFR C677T polymorphism was significantly associated with male infertility and abnormospermia.Three-fifths of the model showed there was a significant association between the MTR A2756G polymorphism and male infertility. Both MTHFR A1298C and MTRR A66G polymorphisms were not significantly associated with male fertility. Furthermore, subgroup analysis revealed a significant association between the MTHFR C677T polymorphism and male fertility in Asian countries.

CONCLUSION

This meta-analysis suggests that the MTHFR C677T and MTR A2756G polymorphisms may be a potential risk factor for male infertility.

Association between methylenetetrahydrofolate reductase C677T polymorphisms and male oligozoospermia, asthenozoospermia or oligoasthenozoospermia: a case-control study

Mutation of methylenetetrahydrofolate reductase (MTHFR) C677T leads to the decrease of folate utilization and the impairment of spermatogenesis. This study attempts to investigate the association between MTHFR C677T polymorphisms and nonobstructive oligozoospermia, asthenozoospermia or oligoasthenozoospermia in the Chinese population. The study cohort comprised 189 patients diagnosed with oligozoospermia, asthenozoospermia or oligoasthenozoospermia, and 626 controls based on clinical examinations. The MTHFR c.677 genotype of all subjects was determined by fluorescence staining in situ hybridization and the significance of different genotype frequencies was further analyzed by Chi-square test. The results showed that the frequency of MTHFR 677 CT genotype in the oligozoospermia, asthenozoospermia and oligoasthenozoospermia group was 33.3%, 38.3% and 44.0% respectively, whereas it was 47.3% in the control group. The P value of Chi-square test was 0.070, 0.103 and 0.654, respectively. The frequency of MTHFR 677 TT genotype in the oligozoospermia, asthenozoospermia and oligoasthenozoospermia group was 31.1%, 11.7% and 18.0% respectively, while that in the control group was 19.5%. The P value of Chi-square test was 0.061, 0.070 and 0.066, respectively. Collectively, there is a weak association between MTHFR C677T polymorphisms and oligozoospermia, asthenozoospermia or oligoasthenozoospermia within the current Chinese population cohort.

Methylenetetrahydrofolate reductase (MTHFR) polymorphisms in andrology-a narrative review

Background and Objective

Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme involved in folate metabolism and one-carbon metabolism. MTHFR gene polymorphism affects enzyme activity. MTHFR gene polymorphism is closely related to many human diseases, such as cardiocerebrovascular diseases, diabetes, neural tube defects (NTDs), tumors, and so on. In the field of Andrology, MTHFR gene polymorphism may be associated with male infertility and erectile dysfunction (ED), and there is a possibility of treating male infertility and ED by supplementing with folic acid. However, its exact pathophysiologic mechanism is not fully understood. We sought to obtain a robust understanding of the interactions between MTHFR gene polymorphism, oxidative stress, DNA methylation, hyperhomocysteinemia (HHcy), male infertility, and ED.

Methods

We performed a non-systematic literature review using the PubMed database to identify articles specifically related to MTHFR, male infertility and ED.

Key Content and Findings

Our literature review on MTHFR gene polymorphism in male infertility patients indicates a significant association between C677T gene polymorphism and male infertility. There is limited literature on the correlation between ED and MTHFR gene polymorphism, and there are two different conclusions, related and unrelated. More clinical data are needed to clarify the conclusion. There is a possibility of using folic acid supplementation to treat male infertility and ED, especially for patients with thymine-thymine (TT) genotype. Future research is necessary to further understand the relationship between MTHFR gene polymorphism and male infertility and ED.

Conclusions

Our literature review on MTHFR gene polymorphism in male infertility patients indicates a significant association between C677T gene polymorphism and male infertility. Folic acid supplementation can improve sperm quality. The correlation between MTHFR gene polymorphisms and ED is questionable and needs to be confirmed by more clinical data. MTHFR gene polymorphisms are associated with homocysteine (Hcy) levels, which affects vascular endothelial function and may be related to the development of vascular ED (VED). Folic acid supplementation improves International Index for Erectile Function (IIEF) questionnaire scores in ED patients in whom phosphodiesterase 5 inhibitor (PDE5i) alone is ineffective.

Positive Effects of a Resveratrol-Based Nutraceutical in Association with Surgical Scleroembolization: A Pilot Retrospective Clinical Trial

Background: Varicocele still today represents a common cause of infertility in young men. The treatment strategy remains a surgical approach such as scleroembolization; however, the complete restoration of spermatic parameters afterward requires an average of six or more months to fully regain optimal seminal parameters. Recently, many studies have demonstrated the beneficial effects of Resveratrol in male fertility, given its potential anti-inflammatory, antiapoptotic, and mitochondrial effects. Therefore, Resveratrol-based nutraceuticals could be promising as an adjuvant to mitigate subfertility in patients with varicocele. Methods: In the present study, we retrospectively analyzed the effects of the administration of a Resveratrol-based nutraceutical after the scleroembolization procedure. The improvement of sperm quality in terms of number, motility, and morphology were considered to be the study's main endpoints. A spreadsheet program was used for data analysis, and a p-value of <0.05 was considered significant. Results: We found a statistically significant improvement in the spermatic parameters (sperm count and total motility) and an increase in normal sperm after only 4 months of treatment. The supplementation with a Resveratrol-based nutraceutical associated with the surgical procedure showed encouraging results if compared to data from a control group and the results reported in the literature linked to scleroembolization practice alone. In fact, there was a clear improvement in the seminal parameters at 4 months. Conclusions: This suggests the positive impact of the Resveratrol-based nutraceutical in synergizing with scleroembolization in reducing the time needed to fully recover sperm function.

Association of methyltetrahydrofolate reductase gene mutation, homocysteine level with semen quality of Iraqi infertile males

Background

Infertility is very common condition and almost 50% of cases are due to male factors. Several genetic and environmental factors are responsible for the poor quality and reduced number of sperms in several cases of infertility. The present study was designed to investigate the association between semen parameters, homocysteine, and the risk of C677T polymorphism of MTHFR gene in infertile males of Iraqi population.

Methods

This Case–control study has been conducted from February 2019 to July 2021 at a molecular laboratory in the Anatomy and Histology Department/college of Medicine/University of Kufa/Najaf/Iraq. It was composed of 353 infertile male patients. They were divided into five groups: 90 azoospermic, 84 oligospermia, 64 asthenospermic, 50 oligoasthenospermic, and 65 teratospermic with an age range 20–46 years compared with 100 fertile males as control with age range 21–49 years. In order to detect homocysteine levels, we used Hcy ELISA Kit. C677T mutation of MTHFR gene was employed by PCR–RFLP technique.

Results

Our data revealed three genotypes of MTHFR C677T, 167 (47.3%) subjects had CC genotype, 116 (32.9%) subjects had CT genotype and 70 (21.1%) subjects had TT genotype. Furthermore, T allele was associated with higher risk of infertility in all patients groups for any genetic model. In total infertile subjects (codominant model: CT vs. CC, OR = 2.0, 95% C.I = 1.2–3.3, P = 0.011; TT vs. CC, OR = 4.8, 95% C.I = 3.3–8.2, P = 0.0003; dominant model: CT + TT vs. CC, OR = 2.8, 95% C.I = 1.7–4.5, P = 0.0001). Oligoasthenospermic patients associated with higher risk in CT heterozygous genotype (OR = 2.8, 95% C.I = 1.0–4.9, P = 0.03) and TT homozygous of mutant allele (OR = 6.3, 95% C.I = 1.9–9.2, P = 0.002). Homocystein level was elevated in all infertile groups when compared with control group (P < 0.01), but the elevation was marked in oligoasthenospermia group. As well as, the level of Serum Hcy exhibited the highest value in TT mutant genotype (39.7 µmol/ml) followed by CT genotype (28.5 µmol/ml) while the lowest level of Hcy recorded in CC genotype (14.6 µmol/ml) for oligoasthenospermia group.

Conclusions

By relating the MTHFR C677T gene mutation with a higher homocystein level, the results showed that Iraqi males with this mutation are more likely to suffer from infertility.

Methylenetetrahydrofolate reductase C677T and A1298C polymorphisms and male infertility risk: An updated meta-analysis

BACKGROUND

18 previous meta-analyses have been published on the methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C polymorphisms with male infertility risk. However, results of the previous meta-analyses were still inconsistent. Moreover, their meta-analyses did not assess false-positive report probabilities except one study. Furthermore, many new studies have been published, and therefore an updated meta-analysis and re-analysis of systematic previous meta-analyses were performed to further explore these issues.

OBJECTIVES

To determine the association between MTHFR C677T and A1298C polymorphisms and male infertility risk.

METHODS

Crude odds ratios and their 95% confidence intervals were used to assess the association between MTHFR C677T and A1298C polymorphisms and male infertility risk. We used the Bayesian false discovery probability (BFDP) to assess the credibility of statistically significant associations.

RESULTS

Fifty-nine studies were included concerning the MTHFR C677T and 28 studies were found on the MTHFR A1298C with male infertility risk. Overall, the MTHFR C677T was associated with increased male infertility risk in overall populations, Africans, East Asians, West Asians, South Asians, azoospermia, and Oligoasthenoteratozoospermia (OAT). In further sensitivity analysis and BFDP test, the positive results were only considered as "noteworthy" in the overall population (TT vs CC: BFDP = 0.294, CT + TT vs CC: BFDP = 0.300, T vs C: BFDP = 0.336), East Asians (TT vs CC: BFDP = 0.089, TT vs CT + CC: BFDP = 0.020, T vs C: BFDP < 0.001), West Asians (TT vs CC: BFDP = 0.584), hospital-based studies (TT vs CC: BFDP = 0.726, TT vs CT + CC: BFDP = 0.126), and OAT (TT vs CT + CC: BFDP = 0.494) for MTHFR C677T. In addition, a significantly increased male infertility risk was found in East Asians and population-based studies for MTHFR A1298C. However, we did not find that the positive results were considered as "noteworthy" in the overall and all subgroup analyses for MTHFR A1298C.

CONCLUSIONS

In summary, this study indicates that the MTHFR C677T is associated with increased male infertility risk in East Asians, West Asians, and OAT. No significant association was observed on the MTHFR A1298C with male infertility risk.

Resveratrol-Based Multivitamin Supplement Increases Sperm Concentration and Motility in Idiopathic Male Infertility: A Pilot Clinical Study

Background. It is known that a multitude of factors may lead to male factor infertility, but still, in the majority of cases, the cause remains largely idiopathic, reflecting poor understanding of the basic process of spermatogenesis and the mechanisms involved. Resveratrol is a polyphenol compound that displays several cellular aspects mainly associated with SIRT1-pathway activation and promotion of mitochondrial enhancer activities. In several animal models, resveratrol has shown positive effects on mitochondria and membrane potential. This could explain effects on sperm concentration and motility. The aim of this study is to evaluate the effects on the semen parameters of GENANTE^®, a multivitamin supplement containing 150 mg of resveratrol/day, in patients with idiopathic infertility. Methods. This was a prospective single center clinical study. Twenty patients took a multivitamin supplement based on 150 mg of resveratrol (GENANTE^®), in the form of an oral tablet every 12 h, and were followed up at 1, 3, and 6 months after treatment. Pre- and post-treatment evaluation included history, clinical examination, semen analysis, hormonal determinations, and scrotal and prostatic ultrasound. Results. Our preliminary pilot study demonstrated that the multivitamin supplement based on resveratrol improves sperm motility (48.3% ± 13.8 vs. 59.0% ± 12.8, p = 0.0001) and concentration (22.6 × 10⁶/m^L ± 9.5 vs. 25.7 × 10⁶/mL ± 8.1, p = 0.0001) after 3 and 6 months of treatment in men with idiopathic infertility. Conclusion. Our data suggest that targeting the metabolic and energetic pathways involved in spermatogenesis and mitochondrial activity could lead to potential effects and counteract subfertility/infertility in men through a mitochondria dynamics mechanism. Trial registration number: ClinicalTrials.gov registration identifier: NCT03864198, registered on 1 January 2019.

The Male Is Significantly Implicated as the Cause of Unexplained Infertility

Male infertility is recognized as a relatively common, complex condition, generated by a broad array of environmental and genetic factors. Historical reliance on the conventional semen profile has tended to underestimate the true contribution of "the male factor" to human infertility. This review highlights the importance of genetic and epigenetic factors in the etiology of male infertility, identifying a range of mutations responsible for primary testicular failure and impaired fertilizing potential. More than three quarters of all de novo mutations arise in the male germline via mechanisms that involve the inefficient or defective repair of DNA damage. Understanding the range of factors capable of creating genetic turmoil in the paternal germline is essential, if we are to gain a deep understanding of the causes of male infertility, rather than just the symptoms that characterize its presence. High levels of DNA fragmentation induced by oxidative stress are part of this equation. Oxidative stress is, in turn, driven by biological (age, ejaculation frequency, varicocele, infection), lifestyle (smoking, obesity), and environmental factors (heat, other forms of electromagnetic radiation, and toxins) that can impair the fertilizing potential of the spermatozoa and influence the incidence of spontaneous mutations that may cause infertility in the offspring.