Glutathione S-transferase gene polymorphisms are not major risks for susceptibility to posttransplantation diabetes mellitus in Taiwan renal transplant recipients

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.

Association between Genetic Polymorphisms and Risk of Kidney Posttransplant Diabetes Mellitus: A Systematic Review and Meta-Analysis

OBJECTIVES

The purpose of this study was to clarify the role of genetic factors on posttransplant diabetes mellitus (PTDM) risk.

METHODS

Relevant publications were systematically retrieved from PubMed, EMBASE, and the Cochrane Library up to December 2020. Data from eligible case-control and cohort studies were extracted for qualitative and quantitative analyses. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to estimate the association between gene polymorphisms and PTDM in the quantitative meta-analysis.

RESULTS

A total of 43 eligible articles were identified, and 16 studies on 9 DNA variants from 8 genes were included in the meta-analysis. TCF7L2 rs7903146 was significantly associated with PTDM risk in 5 genetic models (OR (95% CI): allelic: 1.59 (1.17-2.16), P=0.003; dominant recessive: 1.62 (1.14, 2.31), P=0.007; recessive: 1.87 (1.18, 2.94), P=0.007; homozygote: 2.21 (1.23, 3.94), P=0.008; and heterozygote 1.50 (1.08, 2.10), P=0.017). KCNQ1 rs2237892 was significantly correlated with PTDM risk in 3 genetic models (allelic: 0.68 (0.58, 0.81), P < 0.001; dominant: 0.6 (049, 0.74), P < 0.001; and heterozygote: 0.61 (0.48, 0.76), P < 0.001). KCNJ11 rs5219 was significantly linked with PTDM in the recessive genetic model (1.59 (1.01, 2.50), P=0.047). No significant correlations of PTDM with TCF7L2 rs12255372, SLC30A8 rs13266634, PPARγ rs1801282, CDKN2A/B rs10811661, HHEX rs1111875, and IGF2BP2 rs4402960 polymorphisms were found.

CONCLUSIONS

The gene polymorphisms of TCF7L2 rs7903146, KCNQ1 rs2237892, and KCNJ11 rs5219 may predispose kidney transplant recipients to PTDM. Large sample size studies on diverse ethnic populations were warranted to confirm our findings.

Influence of GSTM1, GSTT1, and GSTP1 genetic polymorphisms on disorders in transplant patients: a systematic review

The glutathione-S-transferase (GST) enzymes are phase II isoenzymes responsible for protection against free radicals and xenobiotics. Since these proteins are described as polymorphic, polymorphisms in genes that encode them may alter enzymatic function and contribute to oxidative stress. In this context, such polymorphisms were already associated with several diseases and multiple therapeutic outcomes. A systematic review was performed to evaluate studies regarding the association between polymorphisms in three genes encoding enzymes of the GST family - GSTM1, GSTT1, and GSTP1 - and disorders in transplant patients. A total of 125 articles on which inclusion and exclusion criteria were applied were identified at PubMed database. Thirty-two studies met the target criteria and were included in the review. The mechanisms by which GST genotypes influence the development of disorders in transplant patients differ by disorder: they may participate in it by decreasing metabolism of drugs administered to patients undergoing transplantation, then exposing them to greater toxicity; by decreasing the repair ability against oxidative stress; or by encoding proteins that may be recognized as foreign, setting of an alloimmune reaction. Although some results are better established - such as GSTM1 null genotype's role in the development of toxicity events in transplant patients - others require further evidences, as GST influence on the development of pulmonary decline and posttransplant diabetes mellitus (PTDM). The importance of investigating these associations lies in a personalized medicine, in which the high-risk genotype patient has its treatment individualized and its care for prophylaxis and surveillance increased, potentially reducing this population's morbimortality.

The GSTM1 and GSTT1 Null Genotypes Increase the Risk for Type 2 Diabetes Mellitus and the Subsequent Development of Diabetic Complications: A Meta-analysis

BACKGROUND

Studies pertaining to association of GSTM1 and GSTT1 null genotypes with risk of T2DM and its complications were often inconclusive, thus spurring the present study.

METHODS

Meta-analysis of 25 studies for evaluating the role of GSTM1/GSTT1 null polymorphisms in determining the risk for T2DM and 17 studies for evaluating the role of GSTM1/GSTT1 null polymorphisms in development of T2DM related complications were conducted.

RESULTS

Our study revealed an association between GSTM1 and GSTT1 null polymorphism with T2DM (GSTM1; OR=1.37;95% CI =1.10-1.70 and GSTT1; OR=1.29;95% CI =1.04-1.61) with an amplified risk of 2.02 fold for combined GSTM1-GSTT1 null genotypes. Furthermore, the GSTT1 null (OR=1.56;95%CI=1.38-1.77) and combined GSTM1-GSTT1 null genotypes (OR=1.91;95%CI=1.25- 2.94) increased the risk for development of T2DM related complications, but not the GSTM1 null genotype. Stratified analyses based on ethnicity revealed GSTM1 and GSTT1 null genotypes increase the risk for T2DM in both Caucasians and Asians, with Asians showing much higher risk of T2DM complications than Caucasians for the same.

DISCUSSION

GSTM1, GSTT1 and combined GSTM1-GSTT1 null polymorphism may be associated with increased risk for T2DM; while GSTT1 and combined GSTM1-GSTT1 null polymorphism may increase the risk of subsequent development of T2DM complications with Asian population carrying an amplified risk for the polymorphism.

CONCLUSION

Thus GSTM1 and GSTT1 null genotypes increases the risk for Type 2 diabetes mellitus alone, in combination or with regards to ethnicity.

Association of Body Mass Index and the Risk of New-Onset Diabetes After Kidney Transplantation: A Meta-analysis

OBJECTIVE

To comprehensively examine the correlation between body mass index (BMI) and the risk of new-onset diabetes after kidney transplantation (NODAT).

METHODS

The electronic databases Pubmed, Embase, and Cochrane Library, updated in December 2016, were searched, and a literature review was conducted as well to identify relevant research studies. With the use of R 3.12 software, the association between BMI and NODAT risk was analyzed by means of a meta-analysis, with the mean differences (MDs) and their 95% confidence intervals (CIs) as effect indexes. Publication bias was assessed with the use of the Egger test. A sensitivity analysis was performed by excluding 1 study at a time. And the overall morbidity of NODAT was calculated.

RESULTS

In the meta-analysis, 55 eligible studies involving 15,458 kidney transplantation cases were included. After the heterogeneity test, the random-effects model was used to calculate the pooled results of the effect indexes. The results of the meta-analysis showed that BMI was an independent risk factor of NODAT (MD, 1.88; 95% CI, 1.48-2.27). No publication bias was found among the included studies (t = 0.3417; P = 0.7339). The sensitivity analysis revealed that the pooled MD did not reverse after ignoring 1 study at a time. In addition, the overall morbidity of NODAT was 21% (95% CI, 21%-23%).

CONCLUSIONS

Our results suggest that BMI is an independent risk factor for NODAT.

Evaluation of glutathione S-transferase P1 (GSTP1) Ile105Val polymorphism and susceptibility to type 2 diabetes mellitus, a meta-analysis

It is well established that type 2 diabetes mellitus (T2DM) is associated with oxidative stress and glutathione S-transferases (GSTs) protect cells against oxidative stress. The missense substitution Ile105Val (rs1695) of the glutathione S-transferase P1 (GSTP1, OMIM: 134660) results from an A/G base substitution at nucleotide 313. Many studies have evaluated the correlation between the rs1695 polymorphism and T2DM, but the results remain inconclusive. The aim of the present meta-analysis was to investigate the association between GSTP1 Ile105Val polymorphism and the susceptibility risk of T2DM. Eligible studies (published before August 2017) were identified in several databases. The heterogeneity between studies was evaluated with the chi-square based Q test and the I2 test. The strengths of the association were assessed by pooled odds ratios (ORs) and the corresponding 95 % confidence interval (95 % CI) using either a fixed or random-effects models. Eighteen studies documenting a total of 2595 T2DM cases and 2888 controls were included in this meta-analysis. In the overall analysis there was no significant association between the rs1695 polymorphism and the risk of T2DM. The subgroup analyses stratified by ethnicity, publication year and sample size did not reveal significant association between the study polymorphism and the risk of T2DM and any sources contributing to the substantial heterogeneity between studies. The present meta-analysis suggested that there was significant heterogeneity between studies. Considering some limi tations of our meta-analysis, further large-scale studies should be done to reach a more comprehensive understanding.

A HuGE Review and Meta-Analyses of Genetic Associations in New Onset Diabetes after Kidney Transplantation

PURPOSE

New onset diabetes after transplantation (NODAT) is a serious complication following solid organ transplantation. There is a genetic contribution to NODAT and we have conducted comprehensive meta-analysis of available genetic data in kidney transplant populations.

METHODS

Relevant articles investigating the association between genetic markers and NODAT were identified by searching PubMed, Web of Science and Google Scholar. SNPs described in a minimum of three studies were included for analysis using a random effects model. The association between identified variants and NODAT was calculated at the per-study level to generate overall significance values and effect sizes.

RESULTS

Searching the literature returned 4,147 citations. Within the 36 eligible articles identified, 18 genetic variants from 12 genes were considered for analysis. Of these, three were significantly associated with NODAT by meta-analysis at the 5% level of significance; CDKAL1 rs10946398 p = 0.006 OR = 1.43, 95% CI = 1.11-1.85 (n = 696 individuals), KCNQ1 rs2237892 p = 0.007 OR = 1.43, 95% CI = 1.10-1.86 (n = 1,270 individuals), and TCF7L2 rs7903146 p = 0.01 OR = 1.41, 95% CI = 1.07-1.85 (n = 2,967 individuals).

CONCLUSION

Evaluating cumulative evidence for SNPs associated with NODAT in kidney transplant recipients has revealed three SNPs associated with NODAT. An adequately powered, dense genome-wide association study will provide more information using a carefully defined NODAT phenotype.

Post-renal transplant diabetes mellitus in korean subjects: superimposition of transplant-related immunosuppressant factors on genetic and type 2 diabetic risk factors

Postrenal transplantation diabetes mellitus (PTDM), or new-onset diabetes after organ transplantation, is an important chronic transplant-associated complication. Similar to type 2 diabetes, decreased insulin secretion and increased insulin resistance are important to the pathophysiologic mechanism behind the development of PTDM. However, β-cell dysfunction rather than insulin resistance seems to be a greater contributing factor in the development of PTDM. Increased age, family history of diabetes, ethnicity, genetic variation, obesity, and hepatitis C are partially accountable for an increased underlying risk of PTDM in renal allograft recipients. In addition, the use of and kinds of immunosuppressive agents are key transplant-associated risk factors. Recently, a number of genetic variants or polymorphisms susceptible to immunosuppressants have been reported to be associated with calcineurin inhibition-induced β-cell dysfunction. The identification of high risk factors of PTDM would help prevent PTDM and improve long-term patient outcomes by allowing for personalized immunosuppressant regimens and by managing cardiovascular risk factors.