Lack of association between glutathione peroxidase1 (GPx1) activity, Pro198Leu polymorphism and stenosis of coronary arteries: A population-based prediction

No evidence for a major effect of three common polymorphisms of the GPx1, MnSOD, and CAT genes on PCOS susceptibility

AIM

Polycystic ovary syndrome (PCOS) is one of the prevalent endocrine-metabolic disorders. It is proposed that oxidative stress contributes to PCOS susceptibility and its metabolic associations. The current study aimed to investigate the influence of GPx1 (rs1050450), MnSOD (rs4880), and Catalase (rs1001179) variants with PCOS susceptibility, for the first time.

METHODS

In a case-control study, 350 Kurdish female volunteers (175 PCOS patients and 175 healthy controls) from Western Iran were studied. Genotyping for GPx1 and MnSOD were done using PCR-RFLP and for CAT the allele-specific PCR method was used.

RESULTS

The percentage of patients suffering from hirsutism, acne, and acanthosis among patients with PCOS were 44.6%, 30.3%, and 14.9%, respectively. Distribution of alleles among patients suffering from PCOS versus healthy women was 'Pro' (69.1% vs 68.8%) and 'Leu' (31.4% vs 31.2%) for Gpx1, 'Ala' (61.43% vs 56.57%) and 'Val' (38.57% vs 43.43%) for MnSOD, and 'C' (83.43% vs 84.57%) and 'T' (16.57% vs 15.43%) for CAT.

CONCLUSION

GPx1 (rs1050450), MnSOD (rs4880), and CAT (rs1001179) variants might not be a risk factor for PCOS.

Association of polymorphisms in genes coding for antioxidant enzymes and human male infertility

PURPOSE

Although oxidative stress is thought to be an important cause of male infertility, primarily due to DNA and cell membrane damage, little is known about the genetic causes underlying suboptimal function of the seminal enzymatic antioxidant system. The aim of this study was to investigate the relationship of four potentially functional polymorphisms associated with oxidative stress pathway genes (superoxide dismutase-SOD2 lle58Thr and SOD2 rs4880, catalase-CAT C-262T, glutathione peroxidase 1-GPX1 Pro200Leu) and two null variants of the glutathione S transferase (GSTT and GSTM) genes and infertility risk.

METHODS

A case control study was conducted on 313 infertile patients and 80 fertile donors. Each ejaculate was subjected to a seminal analysis that included the classical parameters seminal volume, sperm concentration, sperm motility, and sperm morphology, as well as sperm DNA fragmentation (patients only). Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and PCR multiplex methods were carried out for genotyping.

RESULTS

Statistically significant differences were found between fertile donors and infertile patients for SNP CAT C-262T; the CC genotype was related with a twofold increased risk of infertility (odds ratio [OR] = 2.262; 95% confidence interval [CI] = 1.369-3.733; P = 0.001), whereas the CT genotype was associated with a protective effect (OR = 0.401; 95% CI = 0.241-0.667; P = 0.001). Surprisingly, the SOD2 Ile58ssThr SNP was not represented in the sample population, so its frequency in the current population frequenting fertility clinics in Madrid may be very low.

CONCLUSIONS

Our results suggest that the CAT SNP C-262T is potentially associated with an increased risk of male infertility.

Roles of Vascular Oxidative Stress and Nitric Oxide in the Pathogenesis of Atherosclerosis

Major reactive oxygen species (ROS)–producing systems in vascular wall include NADPH (reduced form of nicotinamide adenine dinucleotide phosphate) oxidase, xanthine oxidase, the mitochondrial electron transport chain, and uncoupled endothelial nitric oxide (NO) synthase. ROS at moderate concentrations have important signaling roles under physiological conditions. Excessive or sustained ROS production, however, when exceeding the available antioxidant defense systems, leads to oxidative stress. Animal studies have provided compelling evidence demonstrating the roles of vascular oxidative stress and NO in atherosclerosis. All established cardiovascular risk factors such as hypercholesterolemia, hypertension, diabetes mellitus, and smoking enhance ROS generation and decrease endothelial NO production. Key molecular events in atherogenesis such as oxidative modification of lipoproteins and phospholipids, endothelial cell activation, and macrophage infiltration/activation are facilitated by vascular oxidative stress and inhibited by endothelial NO. Atherosclerosis develops preferentially in vascular regions with disturbed blood flow (arches, branches, and bifurcations). The fact that these sites are associated with enhanced oxidative stress and reduced endothelial NO production is a further indication for the roles of ROS and NO in atherosclerosis. Therefore, prevention of vascular oxidative stress and improvement of endothelial NO production represent reasonable therapeutic strategies in addition to the treatment of established risk factors (hypercholesterolemia, hypertension, and diabetes mellitus).

MnSOD and GPx1 polymorphism relationship with coronary heart disease risk and severity

BACKGROUND

Disturbance of the equilibrium between reactive oxygen species (ROS) and anti-oxidants (AOX) has been implicated in various diseases, including atherosclerosis, the most common pathologic process underlying coronary heart disease (CHD). Thus, the defense systems against ROS are critical protecting blood vessel walls against oxidative damage. In this study, we investigate whether Ala16Val MnSOD and Pro198Leu GPx polymorphisms are associated with CHD susceptibility and/or severity.

METHODS

Both polymorphisms were genotyped in a sample of 203 controls and 164 patients. CHD risk and severity, antioxidant status (enzymatic and/or non enzymatic) and biochemical parameters were assessed and analysed by genotype.

RESULTS

A significant association of MnSOD variant to CHD risk was revealed in males. Males harboring the Val/Val genotype were approximately at twofold increased risk of CHD compared to controls (Ala carriers vs Val/Val, adjusted OR 1.89; 95 % CI 1.18‒3.42, p = 0.03). Significant decreases in SOD activity and total antioxidant status (TAS) were observed in Val carriers and by CHD status. Whereas, no association of GPx variant genotype (Leu/Leu) and activity to cardiopathy events was discerned. CHD severity, as demonstrated by the number of vessel stenosis, was associated with significantly higher frequency of Val allele and LDL levels in CHD subjects.

CONCLUSIONS

Our results showed a lack of association of Pro198Leu GPx polymorphism to CHD risk and severity. However, they suggest that Ala16Val MnSOD polymorphism and decreased antioxidant defences are likely contributed to CHD risk in Tunisian men. Furthermore, the Val encoding MnSOD allele and decreased SOD activity were significantly correlated with CHD stenosis progression.