The relevance of MTHFR C677T, A1298C, and MTRR A66G polymorphisms with response to male infertility in Asians: A meta-analysis

Development of an optimized RPA-PfAgo detection system for MTHFR C677T polymorphism genotyping

This study introduces an efficient RPA-PfAgo detection system for the MTHFR C677T polymorphism, proposing a potential strategy to simplify the genotyping process. By optimizing recombinase polymerase amplification (RPA) with Pyrococcus furiosus Argonaute (PfAgo) nucleases, we achieved DNA amplification at a constant temperature. The assay was fine-tuned through meticulous primer and guide DNA selection, with optimal conditions established at 2.0 µL of MgAc, a reaction temperature of 42 °C, and a 10-minute reaction time for RPA. Further optimization of the PfAgo cleavage assay revealed the ideal concentrations of MnCl2, guide DNA, molecular beacon probes, the PfAgo enzyme, and the RPA product to maximize sensitivity and specificity. Clinical validation of 20 samples showed 100% concordance with Sanger sequencing, confirming the method's precision. The RPA-PfAgo system is a promising tool for on-site genotyping, with broad applications in personalized medicine and disease prevention.

Effects of Ocufolin on retinal microvasculature in patients with mild non-proliferative diabetic retinopathy carrying polymorphisms of the MTHFR gene

INTRODUCTION

To evaluate effects of Ocufolin on retinal microvasculature in mild non-proliferative diabetic retinopathy patients who carried methylenetetrahydrofolate reductase (MTHFR) polymorphisms (DR+MTHFRP).

RESEARCH DESIGN AND METHODS

This is a prospective cohort study. Eight DR+MTHFRP (administrated Ocufolin for 6 months) and 15 normal controls (NCs) were recruited. MTHFR polymorphisms were subtyped as normal, C677T, or A1298C. Best-corrected visual acuity (BCVA) was evaluated. Retinal vessel density (VD) and microstructure were evaluated by optical coherence tomography angiography.

RESULTS

BCVA and vascular indices of DR+MTHFRP at baseline were worse than those of NC and improved. Compared with baseline, DR+MTHFRP had significantly improved BCVA during follow-up period (p<0.05). VD of superficial vascular plexus was increased at 4 months (p=0.012), while VD of retinal vascular network did not change (p>0.05). Carriers of A1298C and C677T showed statistically significant increase in VD at all layers by 6 months, while carriers of C677T alone showed no significant change and carriers of A1298C alone showed decreased density from 4 months to 6 months. Microstructure did not change during the follow-up period.

CONCLUSION

A 6-month intake of Ocufolin is capable of reversing structural changes of microangiopathy in mild non-proliferative DR+MTHFRP. This suggests a novel way to address these impairments prior to catastrophic vision loss.

A Association of MTHFR C677T and MTRR A66G Gene Polymorphisms with Iranian Male Infertility and Its Effect on Seminal Folate and Vitamin B12

Background

The relation between key enzymes in regulation of folate metabolism and male infertility is the subject of numerous studies. We aimed to determine whether 5, 10-methylenetetrahydrofolate reductase (MTHFR) C677T and methionine synthase reductase (MTRR) A66G genotypes are associated with male infertility in Iranian men and to evaluate its effect on seminal levels of folate and vitamin B12.

Materials and Methods

In this retrospective study, semen and peripheral blood samples were collected from 254 men with oligoasthenoteratozoospermia (OAT) and 77 normozoospermic men who attended Avicenna infertility clin- ic. Single nucleotide polymorphism (SNP) analysis was carried out in genomic DNA by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) method for MTHFR C677T and MTRR A66G gene poly- morphisms.

Results

In MTHFR C677T, our founding showed that T carrier was conversely lower in OAT than normozoospermic men (χ²-test=7.245, P=0.02) whereas in MTRR A66G, A and G carrier showed no significant difference between the two groups (χ²-test=1.079, P=0.53). The concentration of seminal folate was not different between normozoospermic (18.83 ± 17.1 ng/ ml) and OAT (16.96 ± 14.2 ng/ml) men (P=0.47). The concentration of vitamin B₁₂ was slightly higher in normozospermic men (522.6 ± 388.1 pg/ml) compared to OAT men (412.9 ± 303.6 pg/ml, P=0.058).

Conclusion

The MTHFR C677T and MTRR A66G have no effect on the concentrations of seminal folate and vitamin B₁₂. The present study showed that two SNPs of MTRR A66G and MTHFR C677T cannot be seen as a risk factor for male factor subfertility.

Exploring the potential impact of nutritionally actionable genetic polymorphisms on idiopathic male infertility: a review of current evidence

Infertility affects about 15% of the world's population. In 40%–50% of infertile couples, a male factor underlies the problem, but in about 50% of these cases, the etiology of male infertility remains unexplained. Some clinical data show that lifestyle interventions may contribute to male reproductive health. Cessation of unhealthy habits is suggested for preserving male fertility; there is growing evidence that most preexisting comorbidities, such as obesity and metabolic syndrome, are highly likely to have an impact on male fertility. The analysis of genetic polymorphisms implicated in metabolic activity represents one of the most exciting areas in the study of genetic causes of male infertility. Although these polymorphisms are not directly connected with male infertility, they may have a role in specific conditions associated with it, that is, metabolic disorders and oxidative stress pathway genes that are potentially associated with an increased risk of male infertility due to DNA and cell membrane damage. Some studies have examined the impact of individual genetic differences and gene-diet interactions on male infertility, but their results have not been synthesized. We review the current research to identify genetic variants that could be tested to improve the chances of conceiving spontaneously through personalized diet and/or oral vitamin and mineral supplementation, by examining the science of genetic modifiers of dietary factors that affect nutritional status and male fertility.

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.

Systemic risk factors correlated with hyperhomocysteinemia for specific MTHFR C677T genotypes and sex in the Chinese population

Background

Methyltetrahydrofolate reductase (MTHFR) is a main regulatory enzyme in homocysteine (Hcy) metabolism. A common C677T mutation in the MTHFR gene results in decreased enzyme activity, which contributes to hyperhomocysteinemia (HHcy). Previous studies have shown that HHcy was correlated with various systemic diseases, such as cardiovascular disease, stroke, cancer, renal failure and so on. However, we hypothesized that HHcy in different genotype and sex groups may have different risk factors, which would lead to various pathologic states. Therefore, the aim of this study was to explore systemic information that are correlated with HHcy for specific MTHFR C677T genotypes and sex, which might be useful for predicting and preventing systemic diseases.

Methods

This cross-sectional study was performed through November 2017 to July 2019. A total of 4,534 adults aged 20–75 y were selected for this study. All the participants underwent a physical examination, blood tests and MTHFRC677T genotyping. Multivariable linear regression was performed to explore the risk factors for HHcy for each sex and genotype.

Results

The average of Hcy level is higher in the TT genotype than CC and CT genotypes (P=0.000). Multiple linear regression analysis identified the common protective factors (folate and Vit B12) and risk factor (Cr) for HHcy. Besides that, each group has its specific risk factors—female-CT (age, SBP, and Hb), female-TT (SBP and AST); male-CC (age, AST and Hb), male-CT (age and AST) and male-TT (SBP, AST, and Hb).

Conclusions

HHcy was associated with different risk factors for each specific sex and genotype. These risk factors might be useful for predicting and preventing systemic diseases.

Association of the MTHFR 677C>T and 1298A>C polymorphisms and male infertility risk: a meta-analysis

BACKGROUND AND OBJECTIVES

One of the possible male sterility risk factors are polymorphisms of Methylenetetrahydrofolate reductase (MTHFR). However, the epidemiologic investigations described inconsistent results regarding MTHFR polymorphism and the risk of male infertility. For that reason, we carried out a meta-analysis of published case-control studies to re-examine the controversy.

METHODS

Electronic searches of Cochrane, EMBASE, Google Scholar, and PubMed were conducted to select eligible studies for this meta-analysis (updated to May 2019). According to our exclusion and inclusion criteria, only high-quality studies that remarked the association between MTHFR polymorphisms and male infertility risk were included. The Crude odds ratio (OR) with a confidence interval of 95% (CI) was used to assess the relationship between MTHFR polymorphism and male infertility risk.

RESULTS

Thirty-four case-control studies with 9662 cases and 9154 controls concerning 677C/T polymorphism and 22 case-control studies with 5893 cases and 6303 controls concerning 1298A/C polymorphism were recruited. Both MTHFR polymorphisms had significant associations with male infertility risk (CT + TT vs. CC: OR = 1.37, 95% CI: 1.21-1.55, P = 0.00, I² = 41.9%); (CC vs. CA + AA: OR = 0.82, 95% CI: 0.52-1.30, P = 0.04, I² = 50.1%). Further, when stratified by ethnicity, the significant association results were observed in Asians and Caucasians for 677C/T and just Asians for 1298A/C.

CONCLUSIONS

Some of MTHFR polymorphisms like MTHFR 677C > T are associated with an elevated male infertility risk. To confirm our conclusion and to provide more accurate and complete gene-environment communication with male infertility risk, more analytical studies are needed.

Adjunctive folate for major mental disorders: A systematic review

OBJECTIVES

This is a meta-analysis of randomized controlled trials (RCTs) to examine the efficacy and safety of adjunctive folate for three major mental disorders (schizophrenia, bipolar disorder, and major depressive disorder (MDD)).

METHODS

Review Manager Program Version 5.3 was used to analyze data.

RESULTS

Fourteen studies with 16 RCTs (n = 1,520) on folate for schizophrenia (4 RCTs, n = 210), mood disorders (i.e., unipolar and bipolar depression) (1 RCT, n = 60), bipolar disorder (2 RCTs, n = 189) and MDD (9 RCTs, n = 1,061) were analyzed separately by diagnosis. For schizophrenia, adjunctive folate was not superior to placebo in terms of total psychopathology (standardized mean difference (SMD) = -0.14, 95% confidential interval (CI): -0.67, 0.39; I² = 30%, P = 0.60), and positive (SMD = 0.09, 95% CI: -0.44, 0.62; I² = not applicable, P = 0.74), negative (SMD = -0.39, 95% CI:-0.84, 0.05; I² = 50%, P = 0.08), and general symptom scores (SMD = -0.33, 95%CI:-0.87, 0.20; I² = not applicable, P = 0.22). For bipolar and unipolar depression, adjunctive folate was significantly superior to placebo in improving depressive symptoms. For bipolar disorder, adjunctive folate was effective in treating the acute phase of mania in bipolar disorder, but not in the acute phase of depression. For MDD, adjunctive folate was significantly superior to placebo in improving depressive symptoms (SMD = -0.38, 95%CI: -0.66, -0.09; I² = 71%, P = 0.01), which was confirmed in 5 of the 10 subgroups. Discontinuation due to any reason and adverse drug reactions were similar between folate and placebo in each diagnostic category.

CONCLUSION

This systematic review found adjunctive folate appeared to be effective and safe for MDD and bipolar manic episode, but it was not effective in treating schizophrenia.

Contribution of MTR A2756G polymorphism and MTRR A66G polymorphism to the risk of idiopathic male infertility

BACKGROUND

Methionine synthase reductase gene (MTRR A66G) polymorphism and methionine synthase gene (MTR A2756G) polymorphism have shown an association with idiopathic male infertility risk in several ethnic populations. However, their small sample sizes and inconsistent outcomes have prevented strong conclusions. We performed a meta-analysis with published studies to evaluate the associations of the 2 single nucleotide polymorphisms (SNPs) and idiopathic male infertility risk.

METHODS

A thorough literature search was performed up to Jun 21, 2019 with Medline, Embase, Web of Science, China National Knowledge Infrastructure (CNKI), China Biology Medical literature (CBM), China Science and Technology Journal Database (VIP), and Chinese literature (Wan Fang) databases. Odds ratio (OR) and 95% confidence interval (95% CI) were used to assess the strength of associations.

RESULTS

Seventeen studies including 3269 cases and 3192 controls met the inclusion criteria. Our meta-analysis showed that the MTR A2756G mutation may contribute to genetic susceptibility to the risk of idiopathic male infertility in Non-Asians, but not to Asian population, whereas the MTRR A66G polymorphism may be unrelated to idiopathic male infertility in both Non-Asian and Asian populations. In the stratified analysis by infertility type, the MTR A2756G polymorphism was a risk factor for both non-obstructive azoospermia (NOA) and oligoasthenoteratozoospermia (OAT) patients. However, the MTRR A66G polymorphism is associated with risk for OAT in Asian, but not in Non-Asian population.

CONCLUSION

This meta-analysis suggested that the MTR A2756G and MTRR A66G polymorphisms were risk factors for idiopathic male infertility. Studies with larger sample sizes and representative population-based cases and well-matched controls are needed to validate our results.