Evaluation of Circulating Plasma VEGF-A, ET-1 and Magnesium Levels as the Predictive Markers for Proliferative Diabetic Retinopathy.

Diabetic retinopathy (DR) is the most common cause for preventable blindness in India. The onset of micro and macrovascular complications in T2DM is multifactorial and difficult to predict. The status of micronutrients, several inflammatory cytokines, elevated triacylglycerols, oxidative stress etc., are being studied extensively. Hypomagnesemia plays a pivotal role in worsening of insulin resistance. Although, Vascular Endothelial Growth Factor-A (VEGF-A) and Endothelin-1 (ET-1) are known to be elevated in DR, yet few reports cite their role, especially in Indian population. In this study, we included thirty subjects with T2DM in each of the three groups namely, T2DM cases without retinopathy, Non Proliferative DR (NPDR) and Proliferative DR (PDR) retinopathy. The glycemic status, circulating plasma VEGF-A, ET-1 levels, serum magnesium and lipids were estimated and compared among the groups. An ROC was drawn to evaluate VEGF-A, ET-1 and serum magnesium levels as the predictive markers for PDR. On comparison VEGF-A, ET-1 and serum magnesium levels showed a significant difference among the three groups. PDR cases had higher circulating levels of VEGF-A, ET-1 and low serum magnesium levels when compared to others. ROC for VEGF-A and ET-1 showed an optimum cut-off of 1521 ng/ml (AUC 0.975) and 16 pg/ml (AUC 0.96) respectively. A negative ROC was drawn to check the lower cut-off limit for serum magnesium; we documented an optimum cut off of 1.7 mg/dl (AUC 0.837). ET-1, VEGF-A and serum Magnesium levels are significantly altered in PDR and can be used as the predictive markers of PDR.