Potential environmental toxicant exposure, metabolizing gene variants and risk of PCOS-A systematic review

Genetic Determinants of Selenium Availability, Selenium-Response, and Risk of Polycystic Ovary Syndrome

Selenium is a trace element and its deficiency has been associated with the risk of PCOS, a multifactorial syndrome that affects a large number of women worldwide. Several databases and literature were searched to find out genetic variants of the genes involved in selenium uptake, metabolism, and regulation which may be significantly associated with the risk of PCOS through Se-related pathways. Genes that require selenium for their biological actions to perform were also shortlisted. A total of eighteen significantly associated genes with forty-four variants were identified as candidate variants that could play a potential role in the modulation of PCOS risk among the study population. The genetic variant distribution data was available in-house and was obtained through a GWAS study of the North India population. In silico tools were applied to understand the functional impact of these variants. Three variants namely LDLR (rs2228671), TNF (rs1041981), and SAA2 (rs2468844) are strongly associated with PCOS risk and have a functional impact on encoded protein. Certain variants of Se uptake genes such as DIO1, GPX2, TXNRD1, DIO2 and GPX3 are also significantly associated with the risk of PCOS development. "C" allele of the Se transporter gene SELENOP (rs9686343) significantly increases PCOS risk. Other potential genes require selenium for their biological actions and are involved in the inflammatory, antioxidant response, and energy homeostasis signaling pathways. Thus, genetic variants of the population may affect the Se availability in the body. Also, deficiency of Se effects may get modulated due to underlying genetic polymorphism of Se-associated genes. This information may be helpful in dosage adjustment of Se supplementation for a population in order to get maximum benefits.

Dimethyl itaconate mitigates histological distortions, inflammation, and oxidative stress in the rat model of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common cause of anovulation and infertility in women. Inflammation and oxidative stress are considered to be the causes of ovarian dysfunction in PCOS. Dimethyl itaconate, as a macrophage-derived immunometabolite, has anti-inflammatory and antioxidative properties, but limited data are available about its effect on female reproductive dysfunctions. The present study aimed to determine the effects of dimethyl itaconate, a cell-permeable derivative of itaconate, on the histological changes, oxidative stress, and inflammation in the ovaries of PCOS rats. In this experimental study, 48 mature female Wistar rats (160-180 g) were randomly divided into the six groups including control, PCOS, PCOS+DMI, PCOS+ metformin, control DMI and control metformin. Following PCOS induction by using testosterone enanthate (1 mg/100 g/day for 35 days), the animals were treated with DMI (50 mg/kg) or metformin (300 mg/kg) for 30 days. At the end of the experimental period, the insulin resistance markers (serum insulin and glucose concentrations, and the homeostasis model assessment of basal insulin resistance (HOMA-IR), oxidative stress index (OSI), and inflammatory cytokines were measured. The process of Folliculogenesis was evaluated by histological examination of the ovary. The results showed that DMI improved insulin resistance and decreased TNF- and IL-1β levels and OSI in the ovarian tissue of rats following androgen-induced PCOS. It also improved steroidogenesis and Folliculogenesis by reducing cystic follicles and ovarian tissue structure. Results indicated that DMI may be a potential candidate to ameliorate PCOS adverse effects by reducing insulin resistance, inflammation, and oxidative stress and restoring ovarian Folliculogenesis.

Genome-wide association study (GWAS) identified PCOS susceptibility variants and replicates reported risk variants

BACKGROUND

Genetic predisposition and environmental factors are considered risk factors for polycystic ovary syndrome (PCOS). Genome-wide association studies (GWAS) have been reported from various subpopulations to evaluate SNPs associated with PCOS risk. No PCOS-associated GWAS study has been reported from India so far.

PURPOSE

The current study was conducted to identify the PCOS-susceptible loci among the North Indian population and to validate the significant loci reported by previous GWAS studies.

METHODS

A total of 272 participants with 134 PCOS patients and 138 age-matched healthy controls were recruited. Genomic DNA was isolated and genotyped by using Infinium Global Screening Array v3.0 microchip considering HWE 10e-5 statistically significant.

RESULTS

A total of fifteen markers have been identified as candidate PCOS risk factors. Only two SNPs, namely rs17186366 and rs11171739 have been identified through replication analysis while comparing the previously reported PCOS GWAS data. In-silico analysis was performed to study the functional impact of identified significant genes for gene ontology, pathways related to gene set, and cluster analysis to determine protein-protein interaction among genes or gene products.

CONCLUSION

The study suggests that multiple variants play an important role in PCOS pathogenesis and emphasizes the importance of further genetic studies among Indian subpopulations. The study also validates two previously reported SNPs in the Indian population. What this study adds to clinical work Study summarizes the importance of candidate gene markers validated by replication and in-silico functional study, significantly involved in PCOS pathogenesis in the studied population. These markers can be used in the future as diagnostic markers for clinical phenotype identification.

Assessment of Serum Elements Concentration and Polycystic Ovary Syndrome (PCOS): Systematic Review and Meta-analysis

Change in the levels of trace elements has been linked with PCOS pathogenesis by various studies, whereas some had reported no such association. Therefore, in order to evaluate association of eleven trace element (Cu, Zn, Cr, Cd, Se, Mn, Fe, Mg, Co, Ni and Pb) serum concentration with PCOS pathogenesis, current systematic review and meta-analysis has been carried out. Literature search was conducted using PubMed, Central Cochrane Library, Google Scholar and Science Direct databases with appropriate keywords. Studies published upto 3rd of September were evaluated for eligibility with suitable inclusion and exclusion criteria. Only case-control studies examining the association of serum trace element concentrations between PCOS cases and controls were selected. Present meta-analysis identified 32 articles with 2317 PCOS and 1898 controls. The serum Cu (MD = 15.40; 95% CI = 4.32 to 26.48; p = 0.006), Co (MD = 0.01; 95% CI = 0.01 to 0.02; p = 0.000), Cr (MD = 0.04; 95% CI = 0.00 to 0.07; p = 0.03) and Fe (MD = 12.98; 95% CI = 5.87-20.09; p = 0.0003) concentration is significantly higher, while lower concentration has been observed for Se (MD =  - 0.99; 95% CI =  - 1.31 to - 0.67; p = 0.000) and Mg (MD =  - 223.41; 95% CI =  - 391.60 to - 55.23; p = 0.009) among women with PCOS in comparison with the healthy group. Concentration of other elements which were analysed is not significantly related to PCOS. In short, PCOS women has higher serum concentrations of Cu, Co, Cr and Fe and lower concentrations of Se and Mg. Studies with sub-population of obese, non-obese and with and without insulin resistance are important to understand the pathomechanism of these elements in the syndrome.