Free radical activity in type 2 diabetes.

Free radical activity has been implicated in the development of diabetic vascular complications in Type 1 diabetes. The aim of the present study was to investigate the levels of free radical scavengers, particularly erythrocyte superoxide dismutase, plasma and erythrocyte lysate thiol, and caeruloplasmin in 22 Type 2 diabetic patients clinically free of complications, and 15 comparable non-diabetic control subjects. The concentration (median (range] of both superoxide dismutase (23 (10-39) vs 45 (25-75) mumol l-1; p less than 0.001) and plasma thiol (374 (172-523) vs 460 (386-595) mumol l-1; p less than 0.01) were reduced in the diabetic group. There were no significant differences in the concentration of erythrocyte lysate thiol (199 (114-520) vs 188 (114-328) mumol l-1) or plasma caeruloplasmin (18 (9-31) vs 24 (6-50) mumol l-1) between the groups. This reduction in superoxide dismutase and the imbalance in the redox status of the plasma and lysate thiol demonstrated is consistent with an increase in free radical activity in Type 2 diabetes.