Manganese Superoxide Dismutase Gene Polymorphism (V16A) is Associated with Diabetic Retinopathy in Slovene (Caucasians) Type 2 Diabetes Patients

Mojca Globočnik Petrovič,Daniel Petrovič,Ines Cilenšek

doi:10.1155/2008/940703

Mojca Globočnik Petrovič, Daniel Petrovič + Show 1 more

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https://doi.org/10.1155/2008/940703

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Abstract

Substantial data indicate that oxidative stress is involved in the development of diabetic retinopathy. Two candidate genes that affect the oxidative stress are manganese mitochondrial superoxide dismutase (Mn-SOD) and endothelial nitric oxide synthase (eNOS). The aim of the present study was to examine the role of the V16A polymorphism of the Mn-SOD gene and the 4a/b polymorphism of the eNOS gene in the development of diabetic retinopathy in Caucasians with type 2 diabetes. In this cross sectional case-control study 426 unrelated Slovene subjects (Caucasians) with type 2 diabetes mellitus were enrolled: 283 patients with diabetic retinopathy and the control group of 143 subjects with type 2 diabetes of duration of more than 10 years who had no clinical signs of diabetic retinopathy. A significantly higher frequency of the VV genotype of the V16A polymorphism of the Mn-SOD was found in patients with diabetic retinopathy compared to those without diabetic retinopathy (OR=2.1, 95% CI = 1.2–3.4; p = 0.006), whereas the 4a/b polymorphism of the eNOS gene failed to yield an association with diabetic retinopathy.We may conclude that the VV genotype of the V16A polymorphism of the Mn-SOD gene was associated with diabetic retinopathy in Caucasians with type 2 diabetes, therefore it might be used as a genetic marker of diabetic retinopathy in Caucasians.

Highlights

Substantial data indicate that oxidative stress is involved in the development of diabetic retinopathy [1, 13,15,17]
The present study provides evidence that the VV genotype of the V16A polymorphism of the mitochondrial superoxide dismutase (Mn-SOD) gene might be a risk factor for diabetic retinopathy in the Slovene population (Caucasians) with type 2 diabetes, whereas the 4a/b polymorphism of the endothelial nitric oxide synthase (eNOS) gene is not
Our findings are in accordance with some reports demonstrating an association of the V16A polymorphism of the Mn-SOD gene with microvascular complications of diabetes [6,24]

Summary

Introduction

Substantial data indicate that oxidative stress is involved in the development of diabetic retinopathy [1, 13,15,17]. Oxidative stress is the result of an imbalance between the amount of reactive oxygen species (ROS) and the capacity of antioxidant defense systems. Increased ROS levels can affect the redox status, and an overall oxidative milieu tends to increase protein phosphorylation and favour cell proliferation [1]. The most common ROS in the cell is the superoxide radical, which is produced during oxidative phosphorylation within mitochondria. A key enzyme in antioxidant defence systems is manganese mitochondrial superoxide dismutase (Mn-SOD), which catalyses the removal of superoxide radicals at the site of production, the matrix side of the inner mitochondrial membrane. The protein encoded by the Val (V) allele, which disrupts the alpha -helix structure, is retained at the level of the

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