Erythrocyte Superoxide Dismutase as a Marker for Nephropathy in Type 2 Diabetes Mellitus: A Pilot Study

Objectives Hyperglycemia, characterized by elevated blood glucose levels, is a consequent upregulation in the generation of reactive oxygen species (ROS). These ROS possess the capacity to induce deleterious modifications in endothelial function. Superoxide dismutase (SOD), an enzymatic antioxidant, stands as the primary scavenger of superoxide, a specific type of ROS, within the extracellular space. This study aims to elucidate the association between the levels of erythrocyte SOD and routinely measured renal function parameters (serum urea and serum creatinine) in type 2 diabetes mellitus (T2DM) patients with nephropathy. Material and Methods Diagnosed patients of T2DM were enrolled in the study conducted at a tertiary care hospital in Delhi, India (n = 120). Erythrocyte SOD concentrations (expressed as units/g of hemoglobin) were determined in 60 T2DM patients with nephropathy (cases) and 60 type 2 diabetes patients without any complications (controls) using a commercially available colorimetric assay kit on an automated analyzer. Serum urea and creatinine levels were measured spectrophotometrically on a clinical chemistry automated analyzer. Data were analyzed using SPSS Statistics (v.20) for statistical inference. Results We observed significantly lower activity of erythrocyte SOD with mean levels of 183 ± 0.78 units/g hemoglobin in subjects with DM nephropathy compared with mean levels of 186 ± 0.95 units/g hemoglobin in the control subjects ( P = 0.03). Our analysis revealed a statistically significant negative association (p-value = 0.02) between erythrocyte SOD activity and serum creatinine levels in DM patients diagnosed with nephropathy. Conclusion Our findings suggest that lower levels of erythrocyte SOD are associated with nephropathy in T2DM.