Common polymorphisms in antioxidant genes are associated with diabetic nephropathy in Type 2 diabetes patients

Association of MnSOD, CAT, and GPx1 Gene Polymorphism with Risk of Diabetic Nephropathy in South Indian Patients: A Case-Control Study

Diabetic nephropathy (DN) is one of the common complications of type 2 diabetes mellitus (T2DM), and oxidative stress plays a key role in the pathogenesis of DN. Studies have demonstrated that antioxidants (MnSOD, CAT, and GPx1) may reduce the complications associated with T2DM. The purpose of the study is to correlate the role of antioxidant gene polymorphisms in the pathogenesis of DN among T2DM individuals in the South Indian population. It clarifies the importance of early manifestation and reliable genetic indicators modulating the oxidative stress mechanism in DN. The study participants were divided and grouped as Group 1: Control, Group 2: T2DM without DN, and Group 3: T2DM with DN (n = 100 in each group). The levels of plasma glucose, HbA1c, renal profile, SOD, CAT, GPx1, MDA, and TAS were assessed. MnSOD (rs4880), CAT (rs1049982), and GPx1 (rs1050450) polymorphisms were genotyped via Tetra-arms PCR. The genotypes of GPx1 depict a significant role in the progression of DN in T2DM patients (co-dominant [OR: 2.134; 95% CI (1.202-3.788), p < 0.01], dominant [OR: 2.015; 95% CI (1.117-3.634), p = 0.02], and recessive model [OR: 2.215; 95% CI (1.235-3.972), p = 0.008]); whereas rs4880 and rs1049982 polymorphisms are not associated with DN progression. As a result, GPx1 (rs1050450) polymorphism could be a diagnostic risk factor for developing DN in T2DM patients. Moreover, the genotypes of rs4880 and rs1049982 polymorphism show significant difference in the antioxidant parameters compared to the genotypes of rs1050450. In contradiction to earlier studies, the current study demonstrates that the genotypes of rs1050450 (GPx1) can be considered as an influential component for higher susceptibility and risk of developing DN in T2DM patients among the South Indian population.

Association of Polymorphisms in Antioxidant Enzyme-Encoding Genes with Diabetic Nephropathy in a Group of Saudi Arabian Patients with Type II Diabetes Mellitus

Introduction

Purpose

Patients and Methods

Results

Conclusion

Genetics of T2DM and Its Chronic Complications: Are We Any Closer to the Individual Prediction of Genetic Risk?

Type 2 diabetes mellitus (T2DM) is a complex disease that has risen in global prevalence over recent decades, resulting in concomitant and enormous socio-economic impacts. In addition to the well-documented risk factors of obesity, poor dietary habits and sedentary lifestyles, genetic background plays a key role in the aetiopathogenesis of diabetes and the development of associated micro- and macrovascular complications. Recent advances in genomic research, notably next-generation sequencing and genome- wide association studies, have greatly improved the efficiency with which genetic backgrounds to complex diseases are analysed. To date, several hundred single-nucleotide polymorphisms have been associated with T2DM or its complications. Given the polygenic background to T2DM (and numerous other complex diseases), the degree of genetic predisposition can be treated as a "continuous trait" quantified by a genetic risk score. Focusing mainly on the Central European population, this review summarizes recent state-of-the-art methods that have enabled us to better determine the genetic architecture of T2DM and the utility of genetic risk scores in disease prediction.

Genetic variability in sodium-glucose cotransporter 2 influences glycemic control and risk for diabetic retinopathy in type 2 diabetes patients

BACKGROUND

Gluconeogenesis and renal glucose excretion in kidneys both play an important role in glucose homeostasis. Sodium-glucose cotransporter (SGLT2), coded by the SLC5A2 gene is responsible for reabsorption up to 99% of the filtered glucose in proximal tubules. SLC5A2 genetic polymorphisms were suggested to influence glucose homeostasis. We investigated if common SLC5A2 rs9934336 polymorphism influences glycemic control and risk for macro or microvascular complications in Slovenian type 2 diabetes (T2D) patients.

METHODS

All 181 clinically well characterized T2D patients were genotyped for SLC5A2 rs9934336 G>A polymorphism. Associations with glycemic control and T2D complications were assessed with nonparametric tests and logistic regression.

RESULTS

SLC5A2 rs9934336 was significantly associated with increased fasting blood glucose levels (P<0.001) and HbA1c levels under the dominant genetic model (P=0.030). After adjustment for T2D duration, significantly higher risk for diabetic retinopathy was present in carriers of at least one polymorphic SLC5A2 rs9934336 A allele compared to non-carriers (OR=7.62; 95%CI=1.65-35.28; P=0.009).

CONCLUSIONS

Our pilot study suggests an important role of SLC5A2 polymorphisms in the physiologic process of glucose reabsorption in kidneys in T2D patients. This is also the first report on the association between SLC5A2 polymorphism and diabetic retinopathy.

Genes associated with Type 2 Diabetes and vascular complications

Type 2 Diabetes (T2D) is a chronic disease associated with a number of micro- and macrovascular complications that increase the morbidity and mortality of patients. The risk of diabetic complications has a strong genetic component. To this end, we sought to evaluate the association of 40 single nucleotide polymorphisms (SNPs) in 21 candidate genes with T2D and its vascular complications in 503 T2D patients and 580 healthy controls. The genes were chosen because previously reported to be associated with T2D complications and/or with the aging process. We replicated the association of T2D risk with IGF2BP rs4402960 and detected novel associations with TERT rs2735940 and rs2736098. The addition of these SNPs to a model including traditional risk factors slightly improved risk prediction. After stratification of patients according to the presence/absence of vascular complications, we found significant associations of variants in the CAT, FTO, and UCP1 genes with diabetic retinopathy and nephropathy. Additionally, a variant in the ADIPOQ gene was found associated with macrovascular complications. Notably, these genes are involved in some way in mitochondrial biology and reactive oxygen species regulation. Hence, our findings strongly suggest a potential link between mitochondrial oxidative homeostasis and individual predisposition to diabetic vascular complications.

The association between antioxidant enzyme polymorphisms and cerebral palsy after perinatal hypoxic-ischaemic encephalopathy

BACKGROUND

Hypoxic-ischaemic perinatal brain injury leads to the formation of reactive oxygen species (ROS) and the resultant cell and tissue damage may cause neurological sequelae such as cerebral palsy and/or epilepsy. A decrease in the capacity for defending against ROS may increase the susceptibility to cerebral palsy. The aim of this study was to investigate the impact of common functional polymorphisms in the antioxidant genes SOD2, GPX1 and CAT, associated with a decreased capacity for defending against ROS, in patients with perinatal hypoxic-ischaemic encephalopathy (HIE).

METHODS

80 patients previously diagnosed with perinatal HIE were included. Genomic DNA was isolated from buccal swabs and genotyped for SOD2 rs4880, GPX1 rs1050450 and CAT rs1001179 using real-time PCR-based methods.

RESULTS

Among patients with neonatal HIE, carriers of at least one polymorphic CAT rs1001179 T allele were significantly associated with development of cerebral palsy compared to non-carriers (univariate logistic regression, p = 0.026; OR = 3.36; 95% CI = 1.16-9.76). This difference remained statistically significant after accounting for prematurity. The investigated SOD2 and GPX1 polymorphisms were not associated with cerebral palsy after perinatal HIE.

CONCLUSION

CAT rs1001179 polymorphism could be used to identify children that have a higher susceptibility to cerebral palsy after perinatal HIE.