Oxidative stress and some antioxidants in plasma of patients with diabetes mellitus

ABSTRACT

Oxidative stress due to increased free oxygen radicals [FOR] generation plays an important role in NIDDM. In this study, levels of the lipid peroxide malondialdehyde [MDA], a marker of FOR[s] activity, together with levels of vitamin C, vitamin E and selenium, three potent antioxidants, were estimated in plasma of 50 patients with NIDDM well matched for body built and duration of disease [< 5 years], as well as in plasma of 25 healthy subjects matched for age, sex, body built and nutritional status, as control. Levels of glycated haemoglobin [GHb], as an index of glycemic control, differentiated patients into two groups[25 patients each], a well controlled group [GHb<9%] and poorly controlled group [GHb>9%]. Results showed significantly decreased levels of the three antioxidants in the poorly controlled group compared to both well controlled group and the controls, with significant decrease in vitamin E and selenium levels in well controlled group compared to controls. Meanwhile, levels of MDA were significantly elevated in both diabetic groups compared to control, with no significant change in between diabetic groups. Negative correlations were noticed between the increase of each of MDA and GHb and the decrease of each of the three antioxidants, while MDA correlated insignificantly with GHb. In conclusion, patients with NIDDM have increased oxidative stress due to increased FOR generation evidenced by increased MDA levels and this stress is not correlated with glycemic control. Also they have deranged some antioxidative mechanisms, more pronounced in poorly controlled patients. Further studies are recommended to uniavel the effects of these changes on the course of the disease