Metabolic Control May Influence the Increased Superoxide Generation in Diabetic Serum

Superoxide anion (O2-) generation in serum from 10 Type 1 diabetic patients and 10 normal subjects was measured ex vivo. The amount of O2- production was significantly increased in diabetic serum 0.41 ± 0.04 (±SD) vs 0.14 ± 0.04 μmol l−1 min−1, p < 0.001) and correlated with fasting plasma glucose and glycosylated protein levels in both diabetic (r = 0.72, p < 0.01, and r = 0.62, p < 0.05) and normal (r = 0.75, p < 0.01 and r = 0.64, p < 0.05) subjects. Improved metabolic control in the diabetic patients was associated with a reduction of serum O2- production (0.28 ± 0.06 μmol l−1 min−1, p < 0.01), but the correlation between O2- levels and fasting plasma glucose and glycosylated protein concentrations was retained (r = 0.86 and r = 0.72, respectively, both p < 0.01).