Free radical activity in obese patients with type 2 diabetes mellitus

Oxidative stress plays critical roles in the pathogenesis of various diseases. The aim of the present study was to investigate the relationship between oxidative stress, measured by plasma dicarbonyls and plasma antioxidant defence, measured by reduced glutathione (G-SH) in the whole blood, protein thiols in the plasma and erythrocyte superoxide dismutase activity in obese and obese with type-2 diabetes mellitus subjects, clinically free of complications. Twenty obese patients with type-2 diabetes mellitus and twenty nondiabetic obese patients were examined and compared with twenty healthy controls (matched for age and sex against the obese patients with or without diabetes).

Obese patients and obese diabetic patients had lower blood glutathione than control subjects (p<0.02 and respectively p<0.04) and higher plasma MDA, an end product of lipid peroxidation (p<0.004 and respectively p<0.01). There was a significant difference between plasma MDA from obese and obese diabetic subjects (p<0.05). Plasma thiols (expressed as micromol/mg protein) did not differ between the three groups. Plasma dicarbonyls concentrations were significantly increased in obese (p<0.043) and obese diabetic patients (p<0.047) and SOD activity (U/g Hb) was significantly decreased in obese (p<0.0 ) and obese diabetic patients (p<0.05) compared to controls. Analysing the results of our study, which show that most of the markers of oxidative stress are modified in the same way in obesity and obesity with diabetes mellitus type 2, we suppose that obesity leads to oxidative stress which can contribute to obesity-associated diseases such as diabetes mellitus.