Enzymatic and genetic evaluation of butyrylcholinesterase in male infertility.

We investigated if substitutions in the ERCC1, ERCC2, and XRCC1 genes of the DNA repair pathway correlate with non-obstructive azoospermia and male infertility. A total of 548 azoospermic infertile males and 410 fertile controls were genotyped for XRCC1 399A > G, 280G > A, and ERCC1 C > A 3' UTR and 541 azoospermic infertile males and 416 fertile controls were genotyped for ERCC2 751A > C using iPLEX Gold Assay. Meta-analyses were performed on XRCC1 399A > G (1022 cases and 1004 controls), ERCC1 C > A 3' UTR (879 cases and 1059 controls), and ERCC2 751A > C (914 cases and 850 controls) polymorphisms to quantitatively estimate the significance of the association between these polymorphisms and the risk of infertility. Statistically significant association between ERCC2 751A > C SNP and male infertility was found using the codominant model (p= 0.03). Results of meta-analysis suggested a lack of correlation with male infertility risk, which could be due to pooling of studies from different ethnic populations. Due to limited the number of studies, a stratified analysis for different ethnic groups could not be performed. In conclusion, AA genotype of 751A > C SNP in ERCC2 correlated with a higher risk of male infertility and may contribute to an increased risk of azoospermia and male infertility in Indian men.

It has been identified that human epididymal protease inhibitor (EPPIN) plays a critical role in sperm function and male fertility. The aim of this study was to determine whether variants of the EPPIN gene are risk factors for idiopathic male infertility. All subjects, including 473 idiopathic infertile men and 198 fertile controls, underwent complete historical and physical examinations. Each subject donated 5 ml of peripheral blood for genomic DNA extraction and serum testosterone evaluation and an ejaculate for semen analysis. The semen analysis was performed by computer-assisted semen analysis system. The serum testosterone level was evaluated by radioimmunoassay. Four tagging single-nucleotide polymorphisms were analyzed by polymerase chain reaction-restriction fragment length polymorphism. We have demonstrated a significant decreased risk of idiopathic infertility with abnormal semen parameters in association with the variant rs2231829, and an increased risk of idiopathic infertility with abnormal semen parameters in association with the variant rs11594. However, among men with normal semen parameters, there were no differences in risk for these genotypes. Furthermore, no significant differences were found for the other variants, rs6124715 and rs2227290, on the risk of male infertility with normal or abnormal semen parameters. Similar serum testosterone levels among different EPPIN genotypes were observed for each group. These results suggest that different variants in the EPPIN gene may have different relationships with idiopathic male infertility and men carrying these variants have a decreased or increased risk of abnormal semen parameters associated with male infertility.

Correlation between LHCGR and NR5A1 genes polymorphism and male infertility risk

To explore the correlation between four tagSNPs of Eppin gene (rs6124715, rs2231829, rs2227290 and rs11594) and the risk of idiopathic male infertility in the Chinese Han population. A total of 473 confirmed infertile patients (from March 2005 to March 2007) and 198 fertile male controls (March 2005 to February 2009) were selected from two hospitals in Nanjing. All the subjects were Han Chinese and came from Nanjing or its surrounding areas. 5 ml peripheral blood was drawn from each subject with informed consent. Four tagSNPs (rs6124715, rs2231829, rs2227290 and rs11594) in Eppin gene were analyzed by the PCR-restriction fragment length polymorphisms (PCR-RFLP) method. The serum testosterone level was evaluated by radioimmunoassay (RIA). The genotype frequencies of AA,AC and CC at rs11594 were 76.3% (361/473), 20.1% (95/473) and 3.6% (17/473) respectively in the case group, while the frequencies in the control group were 75.3% (149/198), 24.2% (48/198), 0.5% (1/198) respectively, the differences were statistically significant (χ² = 7.73, P = 0.021), the CC genotype carriers had an increased risk of male infertility (OR = 7.02, 95% CI:0.93-53.19). In the combined genotype analysis, the haplotype CTGA carriers has significantly lower onset risk (OR = 0.18, 95% CI:0.06-0.53). In the two groups, the frequencies and the risk of male infertility were no statistically significant in rs6124715, rs2231829 and rs2227290 genotype. The Eppin gene polymorphisms were correlated to the susceptibility to idiopathic male infertility. Among them, CC genotype at rs11594 could increase the risk of idiopathic male infertility.

To determine the role of glutathione S-transferases (GSTs; GSTM1, GSTT1, and GSTP1) gene polymorphisms in susceptibility to male factor infertility. We report a pooled analysis of 11 studies on the association of GSTM1, GSTT1, and GSTP1 polymorphisms and male factor infertility, including 1323 cases and 1054 controls. An overall significant association was determined between the GSTM1 null genotype [odds ratio (OR), 2.74; 95% confidence interval (CI), 1.72 to 3.84; P = .003], GSTT1 null genotype (OR, 1.54; 95% CI, 1.43 to 3.47; P = .02), and male factor infertility. The GSTP1 Ile/Val genotype had overall protective effect against development of infertility (OR, 0.48; 95% CI, 0.27 to 0.77), while there was significant heterogeneity between studies. In sensitivity analysis, two studies were excluded; the association and direction between GSTM1 and GSTT1 null genotypes and GSTP1 Ile/Val genotype and male infertility remained unchanged. There was no significant interaction between smoking status and studied genotypes on male infertility risk (P = .26). These results demonstrated that amongst populations studied to date, GSTM1 and GSTT1 null genotypes are associated with strong and modest increase in the risk of male infertility, respectively. On the contrary, GSTP1 Ile/Val genotype has protective effect.

Study of the association between SOD3G362A polymorphism, seminal SOD activity and risk for idiopathic male infertility in Algeria

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.

Obstructive sleep apnea is associated with an increased risk of male infertility, and one of its causes is deviated nasal septum with inferior turbinate hypertrophy (DNS/ITH). However, the risk of male infertility associated with DNS/ITH remains unclear. Using the Taiwan Longitudinal Health Insurance Database, we conducted a retrospective matched cohort study to investigate the risk of infertility in male patients diagnosed with DNS/ITH (N = 61,761) from 2000 to 2015 in comparison with matched controls without DNS/ITH (N = 247,044). We further analyzed the effect of septoturbinoplasty (STP), including septoplasty and turbinoplasty, on the risk of male infertility in DNS/ITH patients. At the end of the follow-up period, 46 (0.07%, 46/61,761, incidence rate: 6.25 per 100,000 person-years) patients developed infertility in the DNS/ITH group versus 72 (0.03%, 72/247,044, incidence rate: 2.28 per 100,000 person-years) in the control group; the incidence rate was 2.740-fold higher in the DNS/ITH group (log-rank P < 0.001). Cox proportional hazards regression revealed that the risk of infertility increased in the DNS/ITH group [adjusted hazard ratio (HR): 1.080, 95% confidence interval (CI), 1.049-1.514, P = 0.001]. Compared with the control group, the risk of infertility was highest in the DNS/ITH group without STP (adjusted HR: 2.842, 95% CI, 1.715-4.082, P < 0.001), followed by the DNS/ITH group with STP (adjusted HR: 1.074, 95% CI, 1.035-1.488, P = 0.012). The intervention of STP reduced the risk of infertility in the DNS/ITH group by 45.1% compared with those without STP (P = 0.033). Clinicians should be aware of the risk of infertility in male patients presenting with DNS/ITH. Improving the nasal airway by STP may decrease the risk of male infertility.

Genetic variants in telomerase reverse transcriptase (TERT) and telomerase-associated protein 1 (TEP1) and the risk of male infertility

Background: Infertility is a major public health and social problem in human reproduction that is known as a multifactorial complex disorder. Genetic background and mutations and single nucleotide polymorphisms (SNPs) on the genes involved in sperm development are the important causes of male infertility. Objectives: In this study, we evaluated the association of AURKC gene polymorphism (rs58264281) and idiopathic male infertility in the Iranian Azeri population. Methods: This study was performed among 100 men with idiopathic infertility (case group) and 100 healthy men with successful fertility (control group) from East Azerbaijan, Iran. Genomic DNA extraction was carried out from peripheral blood samples by the proteinase K method. Genotype analysis was conducted by the tetra-primer amplification refractory mutation system-polymerase chain reaction (Tetra-ARMS PCR). SPSS version 21 was used for the analysis of the obtained data. Results: We observed that the CA and AA genotypes were significantly increased in patients with infertility as compared to healthy controls. Our results demonstrated that the mutant allele of AURKC gene polymorphism (rs58264281) was a significant risk factor in male infertility. Conclusions: We suggested a significant correlation between the AURKC gene rs58264281 polymorphism and male infertility in the Iranian Azeri population. However, further studies are required among other ethnicities, races, and geographic areas with larger sample sizes.

ABSTRACTCatalase (CAT) plays a central role in the protection of different cell types against the deleterious effects of hydrogen peroxide. In human, CAT is implicated in many physiological and pathological conditions including idiopathic male infertility. In this study we examined the association between CAT levels in seminal plasma with different sperm parameters and with CAT–262 C/T polymorphism and their risk for idiopathic male infertility in Algeria. Semen and blood samples were obtained from 111 infertile males and 104 fertile controls from the region of Eastern Algeria following informed consent. Standard semen parameters, DNA integrity, and CAT concentration in seminal plasma were evaluated. CAT-262C/T genotypes were screened using allele specific PCR. Seminal CAT activity was significantly different (p<0.0001) between infertile males and controls, it was also markedly decreased in oligo-astheno-teratozoospermia (p<0.0001), azoospermia (p<0.0001), and normozoospermia (p=0.045) subgroups compared to controls. Positive correlations between CAT activity and semen parameters (volume, motility, concentration, and morphology) were detected, but not with sperm DNA integrity. There was no direct association between CAT-262C/T polymorphism and general male infertility. However, the results presented in this study showed that CAT activity is remarkably associated with the CAT-262T allele (p=0.001) and the different CAT-262C/T genotypes. This study highlighted the major differences in the seminal plasma CAT content between infertile and fertile males and the differences of CAT concentration between different CAT-262C/T genotypes carriers.

Are the four candidate loci (rs7867029, rs7174015, rs12870438 and rs724078) for human male fertility traits, identified in a genome-wide association study (GWAS) of a Hutterite population in the USA, associated with male infertility in a Japanese population? rs7867029, rs7174015 and rs12870438 are significantly associated with the risk of male infertility in a Japanese population. Recently, a GWAS of a Hutterite population in the USA revealed that 41 single-nucleotide polymorphisms (SNPs) were significantly correlated with family size or birth rate. Of these, four SNPs (rs7867029, rs7174015, rs12870438 and rs724078) were found to be associated with semen parameters in ethnically diverse men from Chicago. This is a case-control association study in a total of 917 Japanese subjects, including 791 fertile men, 76 patients with azoospermia and 50 patients with oligozoospermia. Azoospermia was diagnosed on the basis of semen analysis (the absence of sperm in ejaculate), serum hormone levels and physical examinations. Oligozoospermia was defined as a sperm concentration of <20 × 10(6)/ml. We excluded patients with any known cause of infertility (i.e. obstructive azoospermia, varicocele, cryptorchidism, hypogonadotropic hypogonadism, karyotype abnormalities or complete deletion of AZF a, b or c). The SNPs rs7867029, rs7174015, rs12870438 and rs724078 were genotyped using DNA from peripheral blood samples and either restriction fragment length polymorphism PCR or TaqMan probes. Genetic associations between the four SNPs and male infertility were assessed using a logistic regression analysis under three different comparative models (additive, recessive or dominant). The genotypes of all four SNPs were in Hardy-Weinberg equilibrium in the fertile controls. The SNPs rs7867029 and rs7174015 are associated with oligozoospermia [rs7867029: odds ratio (OR) = 1.70, 95% confidence interval (CI) = 1.07-2.68, P = 0.024 (log-additive); rs7174015: OR = 6.52, 95% CI = 1.57-27.10, P = 0.0099 (dominant)] and rs12870438 is associated with azoospermia (OR = 10.90, 95% CI = 2.67-44.60, P = 0.00087 (recessive)] and oligozoospermia [OR = 8.54, 95% CI = 1.52-47.90, P = 0.015 (recessive)]. The association between rs7174015 and oligozoospermia under a dominant model and between rs12870438 and azoospermia under additive and recessive models remained after correction for multiple testing. There were no associations between rs724078 and azoospermia or oligozoospermia. Even though the sample size of case subjects was not very large, we found that three SNPs were associated with the risk of male infertility in a Japanese population. The three infertility-associated SNPs may be contributing to a quantitative reduction in spermatogenesis. This study was supported in part by the Ministry of Health and Welfare of Japan (1013201) (to T.I.), Grant-in-Aids for Scientific Research (C) (23510242) (to A.Ta.) from the Japan Society for the Promotion of Science, the European Union (BMH4-CT96-0314) (to T. I.) and the Takeda Science Foundation (to A.Ta.). None of the authors has any competing interests to declare.

In this study, we evaluate the relationship between genetic polymorphisms of the DJ-1 gene, g.-6_+10del, and g.168_185del with male infertility susceptibility. Four hundred and twenty-two male infertile patients and 285 fertile male controls were recruited. Genotyping was performed by polymerase chain reaction. In silico analysis was performed by EPD, ElemeNT, SNPnexus, and PROMO to predict the potential functions of rs901561484 and rs373653682 polymorphisms. The Del (D) allele carriers of DJ-1 g.-6_+10del polymorphism were significantly associated with the risk of male infertility in total infertile, asthenozoospermia, and oligoasthenozoospermia patients. Moreover, the Del (D) allele of DJ-1 g.-6_+10del polymorphism significantly increased in total male infertile, asthenozoospermia, and oligoasthenozoospermia groups. In addition, the frequencies of different genotypes and the Del allele and Dup allele carriers of DJ-1 g.168_185del gene polymorphisms were associated with male infertility in total infertile and four different sub-group patients. Furthermore, haplotype analysis of DJ-1 g.-6_+10del and g.168_185del polymorphisms revealed that the D-Dup and I-Del haplotype frequencies significantly increased the risk of male infertility, while I-Ins haplotypes were associated with a decreased risk of male infertility in total and sub-group patients. The in silico analysis showed that the presence of Ins and/or Dup alleles of the DJ-1 g.-6_+10del and g.168_185del polymorphisms could provide additional binding sites of more nuclear factors and probably affect transcriptional activity. Our study presents evidence of a strong association between functional polymorphisms of the DJ-1 promoter, g.-6_+10del, and g.168_185del with the risk of male infertility.

Null genotypes of GSTM1 and GSTT1 contribute to male factor infertility risk: a meta-analysis

The Glutathione S-transferases (GSTs) polymorphisms have been implicated in susceptibility to male idiopathic infertility, but study results are still controversial. To investigate the genetic associations between GSTs polymorphisms and risk of male idiopathic infertility, a systematic review and meta-analysis were performed. Meta-analysis was performed by pooling odds ratio (OR) with its corresponding 95 % confidence interval (95 % CI) form studies in electronic databases up to March 16, 2012. Glutathione S-transferase M 1 (GSTM1) null genotype, Glutathione S-transferase T 1 (GSTT1) null genotype, and dual null genotype of GSTM1/GSTT1 were analyzed independently. 14 eligible studies with a total of 1,845 idiopathic infertility males and 1,729 controls were included. There were 13 studies on GSTM1 polymorphism, 10 ones on GSTT1 polymorphism and 5 ones on GSTM1-GSTT1 interaction analysis. Meta-analyses of total relevant studies showed GSTM1 null genotype was significantly associated with an increased risk of male idiopathic infertility (OR = 1.40, 95 % CI 1.07-1.84, P OR = 0.015). The GSTM1-GSTT1 interaction analysis showed dual null genotype of GSTM1/GSTT1 was also significantly associated with increased risk of male idiopathic infertility (OR = 1.85, 95 % CI 1.07-3.21, P OR = 0.028). Subgroup analyses by ethnicity showed the associations above were still statistically significant in Caucasians (For GSTM1, OR = 1.51, 95 % CI 1.11-2.05, P OR = 0.009; For GSTM1/GSTT1, OR = 2.10, 95 % CI 1.51-2.91, P OR < 0.001). This meta-analysis suggests GSTM1 null genotype contributes to increased risk of male idiopathic infertility in Caucasians, and males with dual null genotype of GSTM1/GSTT1 are particularly susceptible to developing idiopathic infertility.