Evaluation of Oxidant Stress in Cases of Myocardial Infarction with and without Diabetes Mellitus.

Abstract

To evaluate oxidant stress and antioxidant activity in cases of myocardial infarction (MI) with and without diabetes mellitus (DM), erythrocyte superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities together with reduced glutathione (GSH) and plasma lipid peroxides (LPO) were estimated in 15 cases of MI without DM, 15 cases of MI with insulin-dependent DM (MI-IDDM), and 14 cases of MI with non-insulin-dependent DM (MI-NIDDM), as well as in 10 normal subjects as controls. SOD activity was significantly lower in both MI-IDDM and MI-NIDDM groups than in the controls. GPx activity was lower in the three MI groups than in the controls. GSH level was significantly lower in the two DM groups than in the controls. GSH level was significantly lower in MI-NIDDM than in MI-IDDM. LPO were significantly higher in the three MI groups than in the controls. LPO were significantly higher in the MI-NIDDM group than in the MI group (p<0.05), Moreover, a significant negative correlation was detected between the plasma LPO level and erythroctye GPx level (r=0.53) and also between the plasma LPO level and the GSH level (r=0.50). These results suggest that oxidative injury in cases of MI results not only from increased free radical production but also from impaired antioxidant defense mechanisms and that the oxidant injury is intensified in cases with DM. Exogenous antioxidants such as vitamins A and E, as well as selenium, may be useful for therapeutic management of these patients.