Biochemical scenario behind initiation of diabetic retinopathy in type 2 diabetes mellitus

Despite the disease having similar glycemic status and duration microangiopathy in some patients develop within few years whereas it doesn't appear as a health complication in some diabetics for a considerable period. This study is undertaken to assess the hyperglycemia-induced biochemical background behind the development of diabetic retinopathy (DR) in type 2 diabetes mellitus (DM).

Following proper diagnosis, 100 patients of type 2 DM of 10-12 years duration having no DR, and 42 patients of type 2 DM of the same duration and glycemic status as the second group, with mild retinopathy were recruited in the study. Lactic acid, glutamate, malondialdehyde (MDA), nitrate, advanced glycation end-products (AGEs), peripheral blood mononuclear cell reactive oxygen species (ROS), vascular endothelial growth factor (VEGF), and its receptor 2 (VEGFR2) in these two groups were produced in an assay following standard methodology.

Biochemical markers of anaerobic glycolysis, lipid peroxidation, AGEs, glutamate concentration, oxidative stress, and expression of VEGF and its VEGFR2 with significantly elevated markings were found in them who developed earliest stage of DR rather than them who had not.

Hyperglycemia-induced anomalous glucose metabolism, lipid peroxidation, advanced glycation, glutamate toxicity, and oxidative stress create a background where apoptosis of retinal capillary endothelial cells invite increased expression of VEGF and VEGFR2, these being the crucial factors behind the development of diabetic microangiopathy.