Influence of antioxidants' gene variants on risk of diabetes mellitus and its complications: a systematic review

A case-control study and systematic review of the association between glutathione S-transferase genes and chronic kidney disease

Background

GSTM1 deletion was reported to be associated with CKD progression in cohort studies. However, the results of case‒control studies were conflicting. The association between GST genes and CKD progression needs to be studied in China. Therefore, we conducted this case‒control study and systematic review for Southwest China to outline the association between GST genes and CKD.

Methods

CKD patients and healthy controls were enrolled from June 1, 2022 to 1 August 2022. Reported case‒control studies were identified by searching databases until 1 September 2022 for meta-analysis.

Results

Significant associations were found between deletions of GSTM1 and GSTT1 and CKD risk (all P < 0.01) but not in GSTP1 rs1695 (all P > 0.05) in Southwest China. Then, we conducted a meta-analysis on 30 studies and found positive associations between deletions of GSTM1 and GSTT1 and CKD risk (all P < 0.01) but failed to find associations in GSTP1 rs1695 (all P > 0.05). Stratification analysis for ethnicity only showed a significant association in Southern Asia (P < 0.05) but not in Eastern Asia or other populations. This was different from our case‒control results. The current evidence was influenced by study quality and PCR method but not by control selection. Given the different stages of CKD patients, a subanalysis of disease stages was performed, and the results remained positive. Interestingly, we found no significant associations between DM-CKD and GST genes, which should be interpreted with caution.

Conclusion

We found that GSTM1 and GSTT1 null genotypes were risk factors for CKD in China. The results of the meta-analysis were somewhat different from our results. We considered that antioxidant therapy might be useful for the treatment of these patients.

Inflammation is associated with impairment of oxidative status, carbohydrate and lipid metabolism in type 2 diabetes complicated by non-alcoholic fatty liver disease

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is accompanied by inflammation and impairment of the lipid metabolism. In addition, NAFLD is one of the major complications of type 2 diabetes associated with oxidative stress. Based on this, we evaluated the tumour necrosis factor alpha (TNF-α), nuclear factor κB (NF-κB), oxidative status rates, and analysed its correlation with carbohydrate and lipid metabolism in patients with NAFLD and type 2 diabetes.

METHODS

A case-control study included 63 participants with NAFLD developing in patients with type 2 diabetes, and 65 healthy volunteers with a normal complete blood count and blood biochemical profile. The following parameters and states were assessed during the study: glycaemia, insulin resistance, lipid levels, liver tests, intensity of free radical induced oxidation, antioxidant enzymes, TNF-α and NF-κB level.

RESULTS

Free radical induced oxidation was significantly elevated (p<0.001), total antioxidant activity was significantly decreased (p<0.001) and associated with insulin resistance (p=0.019) and lipid metabolism shifts (p<0.05) in patients with NAFLD and type 2 diabetes. Such patients had showed impaired functioning of antioxidant system (p<0.001), inhibition of NADPH-generating enzymes activity (p<0.001), increased levels of TNF-α (p<0.001) and NF-κB (p=0.019) correlated with the severity of hyperglycaemia (p<0.05), concentration of reduced glutathione (p=0.005) and total cholesterol (p=0.016).

CONCLUSIONS

The increase of free radical induced oxidation, TNF-α and NF-κB levels, and depletion of the antioxidant system seems to be the key factors of the development of NAFLD in patients with type 2 diabetes.

Evaluation of glutathione S-transferase polymorphism in Iranian patients with type 2 diabetic microangiopathy

Background

Overproduction of reactive oxygen species as a result of hyperglycemia in diabetes mellitus leads to microvascular complications. Glutathione S-transferases play important detoxifying roles with antioxidant potentials. This study aimed to assess whether the glutathione S-transferase M1 and T1 genotypes were associated with type 2 diabetes mellitus microangiopathic complications in the Iranian population.

Results

In this case-control study, the frequencies of null GSTM1 and GSTT1 genotypes were 4/72 (5.56%) and 12/72 (16.67%) respectively, in uncomplicated DM group. The frequencies of null GSTM1 and GSTT1 genotype in complicated DM group were 16/134 (11.94%) and 37/134 (27.61%), respectively. The proportion of GSTM1 null genotypes was higher in diabetic nephropathy compared to non-nephropathy (19.3% vs. 6.04 %, P = 0.006). At GSTT1 locus, patients with diabetic peripheral neuropathy had a higher frequency of deletion compared to those of without neuropathy (30.39% vs. 23.49%) (P = 0.02).

Conclusion

Selective polymorphisms encoding GSTM1 and GSTT1genes may prove useful as genetic markers to recognize individuals with an increased trend in developing diabetic nephropathy and neuropathy, respectively. This will help better identify individuals at higher risk toward microvascular complications of type 2 diabetes due to genetic susceptibility.

Glutathione S-transferases gene polymorphism influence on the age of diabetes type 2 onset

INTRODUCTION

Type 2 diabetes (T2D) is a multifactorial disease affecting mostly adults older than 40 years. The aim of the study was to examine GST gene polymorphism influence on the risk of T2D, especially in young adults.

RESEARCH DESIGN AND METHODS

200 diabetic patients and 221 healthy controls participated in this study. Three GST gene polymorphism have been analyzed: GSTP1 (single-nucleotide polymorphism Ile₁₀₅Val), homozygous deletion of GSTT1 (null/null) and GSTM1 (null/null), using TaqMan real-time quantitative PCR.

RESULTS

The distribution of examined polymorphisms was similar in patient group and control group. Statistically significant differences were demonstrated for the combination of GSTP1 Val/Val and GSTT1 null/null genotypes between patients diagnosed before 40 years of age and healthy people (12.5% vs 0.9%, p=0.016). Moreover, all three examined gene polymorphism together (GSTP1 Val/Val, GSTM1nul/null and GSTT1 null/null genotype) was observed in 12.5% of patients diagnosed before 40 years of age and in 0.5% of healthy individuals (p=0.013).

CONCLUSION

In conclusion, the results suggest that GST polymorphism may be one of the risk factors for developing T2D at a younger age than the T2D population average.

GST null polymorphisms may affect the risk of coronary artery disease: evidence from a meta-analysis

Background

Whether glutathione S-transferase (GST) null polymorphisms, namely GSTM1 null, GSTP1 null and GSTT1 null polymorphisms, influence the risk of coronary artery disease (CAD) or not remains unclear. Thus, the authors performed a meta-analysis to more robustly estimate associations between GST null polymorphisms and the risk of CAD by integrating the results of previous publications.

Methods

Medline, Embase, Wanfang, VIP and CNKI were searched comprehensively for eligible studies, and 45 genetic association studies were finally selected to be included in this meta-analysis.

Results

We found that GSTM1 null polymorphism was significantly associated with the risk of CAD in overall population (OR = 1.37, p = 0.003) and mixed population (OR = 1.61, p = 0.004), GSTP1 null polymorphism was significantly associated with the risk of CAD in overall population (OR = 1.23, p = 0.03), whereas GSTT1 null polymorphism was significantly associated with the risk of CAD in overall population (OR = 1.23, p = 0.02), Caucasians (OR = 1.23, p = 0.02) and East Asians (OR = 1.38, p < 0.0001).

Conclusions

This meta-analysis demonstrated that GSTM1 null, GSTP1 null and GSTT1 null polymorphisms were all significantly associated with an increased risk of CAD.

Association between diabetic retinopathy and interleukin-related gene polymorphisms: a machine learning aided meta-analysis

BACKGROUND

Diabetic retinopathy (DR) is a severe complication of diabetes and a common cause of visual loss in adults. We aimed to assess the correlation between IL gene-related SNPs and the incidence of DR and attempted to predict DR with combined mutation site detection.

METHODS

A systematic search of databases was performed up to August 2019. Five genetic models were used to analyze associations. Machine learning methods were implemented to improve SNP-related disease prediction.

RESULTS

Sixteen trials assessing a total of 7221 patients were included in our meta-analysis. IL6/rs1800795, rs1800796, and IL10/rs1800896 were analyzed. For the IL-6 gene, there was no significant association between rs1800795 and the incidence of DR (allelic model: OR, 1.091; 95% CI, 0.892-1.334; p = .396). There was no significant correlation between rs1800796 (allelic model: OR, 1.135; 95% CI, 0.678-1.901; p = .63), rs1800896 (allelic model: OR, 1.047; 95% CI, 0.788-1.392; p = .752) and the incidence of DR. Unfortunately, the machine learning results also showed that the combined detection of two SNPs could not accurately predict DR occurrence.

CONCLUSION

rs1800795 and rs1800796 in the IL-6 gene and rs1800896 in IL-10 gene are not related to the incidence of DR. Mutations in multiple SNPs for each DR patient still need to be specifically assessed to increase prediction accuracy.

Genetic polymorphisms of antioxidant enzymes CAT and SOD affect the outcome of clinical, biochemical, and anthropometric variables in people with obesity under a dietary intervention

BACKGROUND

Genetic polymorphisms of antioxidant enzymes CAT, GPX, and SOD are involved in the etiology of obesity and its principal comorbidities. The aim of the present study was to analyze the effect of aforementioned SNPs over the output of several variables in people with obesity after a nutritional intervention. The study included 92 Mexican women, which received a dietary intervention by 3 months. Participants were genotyped and stratified into two groups: (1) carriers; mutated homozygous plus heterozygous (CR) and (2) homozygous wild type (WT). A comparison between CR and WT was done in clinical (CV), biochemical (BV), and anthropometric variables (AV), at the beginning and at the end of the intervention.

RESULTS

Participants (n = 92) showed statistically significant differences (p < 0.05) at the end of the nutritional intervention in several CV, BV, and AV. However, two kinds of responses were observed after genotyping participants: (A) CR and WT showed statistically significant differences (p < 0.05) in several CV, BV, and AV for the SNPs 599C>T GPX1 (rs1050450), - 251A>G SOD1 (rs2070424), and - 262C>T CAT (rs1001179). (B) Only CR showed statistically changes (p < 0.05) in several CV, BV, and AV for the SNPs - 21A>T CAT (rs7943316) and 47C>T SOD2 (rs4880). The dietary intervention effect was statistically significantly between the polymorphisms of 47C>T SOD2 and BMI, SBP, TBARS, total cholesterol, and C-LCL (p < 0.05) and between the polymorphisms of - 21A>T CAT (rs7943316) and SBP, DBP, total cholesterol, and atherogenic index (p < 0.05).

CONCLUSION

People with obesity display different response in several CV, BV, and AV after a nutritional intervention, depending on the antioxidant genetic background of SOD and CAT enzymes.