Investigation of the association of endothelial nitric oxide synthase (eNOS)-T786C gene polymorphism with the risk of male infertility in an Iranian population

Variation of the genes encoding antioxidant enzymes SOD2 (rs4880), GPX1 (rs1050450), and CAT (rs1001179) and susceptibility to male infertility: a genetic association study and in silico analysis

Enzymatic factors including superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase (CAT) are among the most important protective antioxidant systems in human semen. This study was conducted to investigate the association between the activities of the mentioned enzymes in semen and also the association between SOD2 rs4880, GPX1 rs1050450, and CAT rs1001179 polymorphisms with male infertility, which was followed by a bioinformatics approach. In a case-control study, 223 infertile men and 154 healthy fertile men were included in the study. After extracting genomic DNA from semen samples, the genotype of rs1001179, rs1050450, and rs4880 polymorphisms was determined using the PCR-RFLP. Next, the activities of SOD, CAT, and GPX enzymes were also measured in semen. Bioinformatics software was used to investigate the effect of polymorphisms on the function of genes. Data analysis indicated that rs1001179 polymorphisms were not associated with male infertility. But our data revealed that the rs1050450 polymorphism is associated with a reduced risk of male infertility as well as asthenozoospermia and teratozoospermia. In addition, rs4880 polymorphism was associated with an increased risk of male infertility as well as teratozoospermia. Further analysis showed that the activity of the CAT enzyme in the infertile group is significantly higher than in the fertile group, but the activity of GPX and SOD enzymes in the infertile group is significantly lower than in the fertile group. Bioinformatic analysis showed that rs1001179 polymorphism affects the transcription factors binding site upstream of the gene, while rs1050450 and rs4880 polymorphisms had an essential role in protein structure and function. On the other hand, rs1050450 (T allele) was exposed to a reduced risk of male infertility and may be a protective factor. And SOD2 rs4880 (C allele) is associated with an increased risk of male infertility, and it is considered a risk factor for male infertility. To reach accurate results, we recommend that the study of SOD2 rs4880 and GPX1 rs1050450 polymorphism effects in the different populations with a larger sample size and meta-analysis are needed.

Genetic variations of antioxidant genes and their association with male infertility in Vietnamese men

BACKGROUND

Antioxidant genes, such as superoxide dismutase (SOD), catalase (CAT), and nitric oxide synthase (NOS), play critical roles in spermatogenesis and sperm functions. Polymorphisms of antioxidant genes have been shown to be strongly associated with sperm quality which affects male fertility.

METHODS

To investigate the association of antioxidant gene polymorphisms to male infertility in Vietnamese men, in this case-control study, using Sanger sequencing, we genotyped four variants SOD1:7958G>A, SOD2:c.47T>C, CAT:-262C>T, and NOS3:-786C>T.

RESULTS AND CONCLUSIONS

We identified SOD1:7958GA genotype and NOS3:-786CT genotype in the infertility group were significantly higher than in the control with OR = 2.191 (95% CI: 1.226-3.915, p = 0.004) and OR = 3.135 (95% CI: 1.591-6.180, p < 0.001), respectively. We also detected that the frequency of the SOD2:c.47TC genotype was significantly higher in the male infertility group than in fertile men (OR = 1.941, 95% CI: 1.063-3.595, p = 0.029). Gene-gene interactions between the SNPs of SOD1, SOD2, and CAT might increase the risk of male infertility patients. In particular, patients carrying the SOD1:GA+AA, SOD2:TC+CC, and CAT:CT/TT genotype pattern have an increased risk of male infertility (OR = 7.614, p = 0.007). To our knowledge, this is the first study to evaluate the association between the SOD1:7958G>A polymorphism and male infertility. Further studies with larger sample sizes and more genes are needed to better assess the association between variants of antioxidant genes and male infertility.

The "Hitchhiker's Guide to the Galaxy" of Endothelial Dysfunction Markers in Human Fertility

Endothelial dysfunction is an early event in the pathogenesis of atherosclerosis and represents the first step in the pathogenesis of cardiovascular diseases. The evaluation of endothelial health is fundamental in clinical practice and several direct and indirect markers have been suggested so far to identify any alterations in endothelial homeostasis. Alongside the known endothelial role on vascular health, several pieces of evidence have demonstrated that proper endothelial functioning plays a key role in human fertility and reproduction. Therefore, this state-of-the-art review updates the endothelial health markers discriminating between those available for clinical practice or for research purposes and their application in human fertility. Moreover, new molecules potentially helpful to clarify the link between endothelial and reproductive health are evaluated herein.