High Blood Superoxide Dismutase (SOD) States in Patients with Diabetes Mellitus

Dependence on Extracellular (EC)-SOD

Abstract

Total SOD activity and EC-SOD concentrations in the serum of 367 patients with type-2 diabetes mellitus were measured. The correlation between the two SOD was r=0.338, a significant relationship (p<0.01). High blood SOD states (total SOD>4.0U/ml) tended to depend on the level of extracellular (EC)-SOD. There were 26 patients (7.1%) in the high EC-SOD (>500ng/ml) group and341 (92.9%) in the low ECSOD (<200ng/ml) group. In the low-EC-SOD group, the correlation between EC-SOD and albumin excretion index (AEI) was r=0.170 (p<0.01). Serum EC-SOD concentrations were81.1±21.9 ng/ml in the normoalbuminuric group (N=214), 83.2±19.8 ng/ml in the microalbuminuric group (N=100) and102.9±35.3ng/ml in the macroalbuminuric group (N=27), and were significantly higher in than the healthy group (N=53) at 73.1±16.7ng/ml (p<0.01), indicating that the serum EC-SOD concentration increased with the development of nephropathy. This study therefore shows that total SOD activation is highly dependent on the level of EC-SOD, and suggests that active oxygen is related to the onset and escalation of diabetic nephropathy. EC-SOD was thus effective as a marker for this disease.