Association of GSTM1 and GSTT1 Null Genotypes with Toluene Diisocyanate-Induced Asthma

Progonostic effect of GSTM1/GSTT1 polymorphism in determining cardiovascular diseases risk among type 2 diabetes patients in South Indian population

BACKGROUND

Cardiovascular disease (CVD) is a significant complication of type 2 diabetes mellitus (T2DM), with oxidative stress playing a significant role. Glutathione S-transferase (GST) polymorphisms - GSTM1, GSTT1 - have been linked to CVD and T2DM. The role of GSTM1 and GSTT1 in CVD development among T2DM patients in the South Indian population is investigated in this study.

MATERIALS AND METHODS

The volunteers were grouped as Group 1: control, Group 2: T2DM, Group 3: CVD, and Group 4: T2DM with CVD (n = 100 each). Blood glucose, lipid profile, plasma GST, MDA, and total antioxidants were measured. GSTM1 and GSTT1 were genotyped using PCR.

RESULTS

GSTT1 plays a significant role in the development of T2DM and CVD [OR 2.96(1.64-5.33), < 0.001 and 3.05(1.67-5.58), < 0.001] while GSTM1 null genotype was not associated with disease development. Individuals with dual null GSTM1/GSTT1 genotype had the highest risk of developing CVD [3.70(1.50-9.11), 0.004]. Group 2 and 3 individuals showed higher lipid peroxidation and lower total antioxidant levels. Pathway analysis further indicated that GSTT1 significantly affects GST plasma levels.

CONCLUSION

GSTT1 null genotype may be considered a contributing factor that increases the susceptibility and risk of CVD and T2DM in the South Indian population.

The Leucocyte Telomere Length, GSTM1 and GSTT1 Null Genotypes and the Risk of Chronic Obstructive Pulmonary Disease

Simple Summary

Chronic obstructive pulmonary disease (COPD) is characterized by chronic inflammation and oxidative stress, both in the airways and blood, and in other organs. Elevated oxidative stress and inflammation have been reported to affect leucocyte telomere length (LTL). We explored the link between GSTM1 and GSTT1 gene polymorphisms, LTL and COPD risk. For GSTM1 and GSTT1, we genotyped 152 COPD patients and 131 non-affected controls, while for TL, we assessed 91 patients and 88 controls. There was a significant difference in GSTM1 null genotype frequency between the patients and controls (0.59 vs. 0.38, p ≤ 0.000), but such was not found for GSTT1 (p = 0.192). COPD patients carrying the GSTM1 null genotype had shorter telomeres compared to those carrying the non-null genotype (15,720 bp vs. 22,442 bp, p = 0.008); and in controls, the opposite occurred (31,354 bp vs. 17,800 bp, p = 0.020). According to our results GSTM1, but not GSTT1, null genotypes might play role in leucocyte telomere shortening, and thus be involved in the pathogenesis of COPD.

Abstract

Chronic obstructive pulmonary disease (COPD) is characterized by chronic inflammation and oxidative stress both in the airways and blood and other organs. Elevated oxidative stress and inflammation have been reported to affect leucocyte telomere length (LTL). Glutathione S-transferase (GST) enzymes are a large family of xenobiotic-metabolizing enzymes that utilize different ROS products. We aimed to explore the link between GSTM1 and GSTT1 gene polymorphisms, LTL and COPD risk. For GSTM1, we genotyped 152 COPD patients and 131 non-affected controls; for GSTT1, we genotyped 149 COPD patients and 130 controls. We were able to assess TL for 91 patients and 88 controls. There was a significant difference in the GSTM1 null genotype frequency between the patients and controls (0.59 vs. 0.38, p ≤ 0.000), but such was not found for GSTT1 (p = 0.192). When combining both polymorphisms, we obtained a significantly greater presence of at least one null genotype among patients (0.12 vs. 0.05, p = 0.027). An association between GSTT1 and LTL was not found. COPD patients carrying the GSTM1 null genotype had shorter telomeres compared to those carrying the non-null genotype (15,720 bp vs. 22,442 bp, p = 0.008); as for the controls, it was the opposite (31,354 bp vs. 17,800 bp, p = 0.020). The significance in both groups remained when combining GSTM1 and GSTT1 (COPD (at least one null) 16,409 bp vs. COPD (non-null) 22,092 bp, p = 0.029; control (at least one null) 29,666 bp vs. control (non-null) 16,370 bp, p = 0.027). The total glutathione level in GSTM1 non-null controls was higher compared to the null genotype (15.39 ng/mL vs. 5.53 ng/mL, p = 0.002). In COPD patients, we found no association (p = 0.301). In conclusion, according to our results, GSTM1, but not GSTT1, null genotypes might play a role in leucocyte telomere shortening, and thus be involved in the pathogenesis of COPD.