Assessment of the association between GSTM1 null genotype and risk of type 2 diabetes

The GSTO2 (rs156697) Polymorphism Modifies Diabetic Nephropathy Risk

Background and Objectives: In the development of type 2 diabetes mellitus (T2DM) and its complications, genetic and environmental factors play important roles. Diabetic nephropathy (DN), one of the major microangiopathic chronic diabetic complications, is associated with an increased risk of major cardiovascular events and all-cause mortality. The present study was designed to investigate the possible modifying effect of glutathione transferase polymorphisms (GSTM1, GSTT1, GSTP1 rs1138272/rs1695, GSTO1 rs4925 and GSTO2 rs156697) in the susceptibility to T2DM and diabetic nephropathy. Materials and Methods: GSTM1 and GSTT1 deletion polymorphisms were determined by multiplex PCR, whereas GSTO1, GSTO2, and GSTP1 polymorphisms were determined by the real-time PCR in 160 T2DM patients and 248 age- and gender-matched controls. Advanced glycation end products (AGEs) were measured by ELISA. Results: Among six investigated GST polymorphisms, a significant association between the GST genotypes and susceptibility for development of diabetes mellitus was found for the GSTM1, GSTT1, GSTP1 (rs1138272) and GSTO1 polymorphisms. When the GST genotypes’ distribution in diabetes patients was assessed in the subgroups with and without diabetic nephropathy, a significant association was found only for the GSTO2 rs156697 polymorphism. Diabetic patients, carriers of the GSTM1 null, GSTT1 null and variant GSTO1*AA genotypes, had significantly increased levels of AGEs in comparison with carriers of the GSTM1 active, GSTT1 active and referent GSTO1*CC genotypes (p < 0.001, p < 0.001, p = 0.004, respectively). Conclusions: The present study supports the hypothesis that GST polymorphisms modulate the risk of diabetes and diabetic nephropathy and influence the AGEs concentration, suggesting the potential regulatory role of these enzymes in redox homeostasis disturbances.

Individual and combined effects of the GSTM1, GSTT1, and GSTP1 polymorphisms on type 2 diabetes mellitus risk: A systematic review and meta-analysis

Backgrounds: Compared with previously published meta-analyses, this is the first study to investigate the combined effects of glutathione-S-transferase polymorphisms (GSTM1, GSTT1 and GSTP1 IIe105Val) and type 2 diabetes mellitus (T2DM) risk; moreover, the credibility of statistically significant associations was assessed; furthermore, many new original studies were published. Objectives: To determine the relationship between GSTM1, GSTT1, and GSTP1 polymorphisms with T2DM risk. Methods: PubMed, Embase, Wanfang, and China National Knowledge Infrastructure Databases were searched. We quantify the relationship using crude odds ratios and their 95% confidence intervals Moreover, the Venice criteria, false-positive report probability (FPRP), and Bayesian false discovery probability (BFDP) were used to validate the significance of the results. Results: Overall, significantly increased T2DM risk was found between individual and combined effects of GSTM1, GSTT1, and GSTP1 polymorphisms on T2DM risk, but, combined effects of the GSTT1 and GSTP1 polymorphisms was not statistically significant. GSTT1 gene polymorphism significantly increases the risk of T2DM complications, while GSTM1 and GSTP1 polymorphisms had no statistical significance. The GSTM1 null genotype was linked to a particularly increased risk of T2DM in Caucasians; the GSTT1 null genotype was connected to a significantly higher risk of T2DM in Asians and Indians; and the GSTP1 IIe105Val polymorphism was related to a substantially increased T2DM risk in Indians. Moreover, the GSTM1 and GSTT1 double null genotype was associated with substantially increased T2DM risk in Caucasians and Indians; the combined effects of GSTM1 and GSTP1 polymorphisms was associated with higher T2DM risk in Caucasians. However, all significant results were false when the Venice criteria, FPRP, and BFDP test were used (any FPRP >0.2 and BFDP value >0.8). Conclusion: The current analysis strongly suggests that the individual and combined effects of GSTM1, GSTT1 and GSTP1 polymorphisms might not be connected with elevated T2DM risk.

Lack of association between glutathione S-transferase M1 and T1 gene polymorphisms and susceptibility to preeclampsia: An updated systematic review and meta-analysis

Insufficient response to oxidative stress in placenta is proposed as a contributing factor for preeclampsia (PE) development. Glutathione S-transferases (GST) have significant role in detoxification processes. Conflicting results were published by several research groups regarding GST T1 and GST M1 deletion polymorphism as risk factors for PE. The aim of the present meta-analysis was to get a better understanding of the impact of these polymorphisms in preeclampsia development. To identify relevant case-control studies, the author team searched Clarivate Analytics Web of Science, Scopus, PubMed, Cochrane Central Register of Controlled Trials, China National Knowledge Infrastructure, major subject journals, and gray literature. Pooled odds ratios and 95% confidence intervals for GST M1 and GST T1 deletion polymorphism and preeclampsia were derived from random effects models. This meta-analysis included 10 eligible studies. The pooled analyses showed no association between GST M1/GST T1 deletion polymorphisms and susceptibility to PE. Even though high heterogeneity was founded among results for GST M1 and double null genotypes, Egger's and Begg's tests (0.17 and 0.18, respectively) revealed no statistical evidence of publication bias among included studies. The present updated systematic review and meta-analysis found no association between GST M1 and GST T1 deletion polymorphism and PE risk.

Glutathione-S-transferase M1 polymorphism and pro-inflammatory cytokines tumour necrosis factor-α and interleukin-1β are associated with preeclampsia in Serbian women

PROBLEM

Preeclampsia has a multifactorial origin with genetic, immunological, and environmental factors described as main contributors to its onset. This study aimed to investigate glutathione-S-transferase M1 (GSTM1) and glutathione-S-transferase T1 (GSTT1) gene polymorphisms, the expression of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6), and the potential relationship between GST polymorphisms and cytokine expression levels in preeclampsia and uncomplicated pregnancy.

METHOD OF STUDY

This prospective case-control study included 50 women with preeclampsia and 50 healthy pregnant women. DNA and RNA were extracted from women leukocytes. Deletion polymorphisms were analyzed by PCR, while cytokine mRNA expression was analyzed by real-time PCR.

RESULTS

GSTM1 null genotype with present GSTT1 increased the risk for preeclampsia development. Deletion of GSTT1 without deletion of GSTM1 increased the risk for early preeclampsia. Relative mRNA expression of TNF-α was significantly higher in preeclampsia compared to healthy pregnant women (P = 0.006). Expression of IL-1β was significantly higher in severe and late preeclampsia compared to the control group (P = 0.005, P = 0.007, respectively). A significant positive correlation between TNF-α and IL-1β was observed (Spearman's ρ = 0.312, P = 0.028) and between IL-1β and IL-6, in preeclampsia group (Spearman's ρ = 0.296, P = 0.037). IL-1β was significantly increased in patients with GSTT1 null genotype (P = 0.015) while IL-6 was increased in patients with GSTM1 null genotype (P = 0.015).

CONCLUSIONS

GSTM1 null genotype represents a risk factor for preeclampsia development, while GSTT1 null genotype favors early preeclampsia. Preeclampsia is also associated with increased expression of pro-inflammatory cytokines, predominantly TNF-α and IL-1β.

Polymorphisms of Antioxidant Genes as a Target for Diabetes Management

Diabetes mellitus (DM) is one of the most important health problems with increasing prevalence worldwide. Oxidative stress, a result of imbalance between reactive oxygen species (ROS) generation and antioxidant defense mechanisms has been demonstrated as the main pathology in DM. Hyperglycemia-induced ROS productions can induce oxidative stress through four major molecular mechanisms including the polyol pathway, advanced glycation end- products formation, activation of protein kinase C isoforms, and the hexosamine pathways. In the development of type 2 DM (T2DM) and its complications, genetic and environmental factors play important roles. Therefore, the aim of this review was to focus on the assessment of single-nucleotide polymorphisms within antioxidant enzymes including superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase, nitric oxide synthase, and NAD(P)H oxidase and their association with T2DM. The results would be helpful in understanding the mechanisms involved in pathogenesis of disease besides discovering new treatment approaches in management of DM.