Oxidative damage, plasma antioxidant capacity, and glucemic control in elderly NIDDM patients.

A study of oxidative damage was made in elderly noninsulin-dependent diabetes mellitus (NIDDM) patients. A statistically significant increase in glucose and fructosamine was found in fasting NIDDM patients, as well as an increase in the oxidation induced by tert-butyl hydroperoxide. The Total Reactive Antioxidant Potential (TRAP) of the plasma was much reduced (p < .02) and the uricemia was unchanged. The erythrocytes of diabetic patients show greater basal oxidation products (p < .05), and the susceptibility of the diabetic erythrocytes to oxidation injury was also shown to increase in the oxidation induced by t-BOOH (p < .05). Linear regression studies showed that TRAP was associated directly with uric acid (p < .05) and inversely with fructosamine and with glucose (p < .03 and p < .05 respectively) in patients with NIDDM, but not in the controls. The levels of fructosamine were found to be related to the basal damage of the red blood cells (direct correlation, p < .001). This study suggest an useful approach to diabetic oxidative stress for clinical settings.