Polymorphisms of superoxide dismutases and catalase and diabetes mellitus

Background: Reactive oxygen species generated by hyperglycemia modify structure and function of lipids, proteins and other molecules taking part in chronic vascular changes in diabetes. Low activity of scavenger enzymes has been observed in diabetic patients and their protective role in oxidative stress may be deteriorated. This study was undertaken to investigate the association between polymorphisms of selected genes of antioxidant enzymes and diabetic macroand microangiopathy. Results: Significant differences in allele and genotype distribution among T1DM,T2DM and control persons were found in SOD1 and SOD2 genes but not in CAT gene, with p <0,01. Serum SOD activity was significantly decreased in T1DM and T2DM subjects compared to the control subjects with p<0,05. SOD1 and SOD2 polymorphisms affected SOD activity. Serum SOD activity was higher in CC than in TT genotype of SOD2 gene and higher in AA than in CC genotype of SOD1, both with p<0,05. Better diabetes control was found in patients with CC than with TT genotype of SOD2 gene. Significantly different allele and genotype frequencies of SOD2 gene polymorphism were found among diabetic patients with macroangiopathy and those without it. No difference was associated with microangiopathy in all genes. Conclusions:The results of our study demonstrate that oxidative stress in diabetes mellitus can be accelerated not only due to increased production ROS by hyperglycemia but also by reduced ability of antioxidant defense caused at least partly by genetic polymorphisms of some scavenger enzymes.