Antioxidant systems in polymorphonuclear leucocytes of Type 2 diabetes mellitus

Aims. To examine the effect of Type 2 diabetes mellitus (DM) on enzymes of importance for oxygen-dependent killing of microorganisms by leucocytes. Methods. Twenty patients with Type 20 DM and 20 nondiabetic controls provid ed blood samples for analysis. Results. The superoxide dismutase (SOD) activity was lower by 41% in polymo rphonuclear leucocytes (PMNL) from patients with Type 2 DM than in controls (3.42 +/- 0.32 U/mg of protein vs. 5.79 +/- 0.71 U/mg of protein, P < 0.00 5). Glutathione peroxidase (GSHPx) and glutathione reductase (GR) activitie s of Type 2 DM patients were 73.04% and 81.12% of control values (0.84 +/- 0.07 nkat/mg of protein vs. 1.15 +/- 0.10 nkat/mg of protein, P < 0.023, an d 2.02 +/- 0.12 nkat/mg of protein vs. 2 49 +/- 0.16 nkat/mg of protein, P < 0.023, respectively). The catalase activity showed no significant differe nce. A significant increase (141.37% of control) in the concentration of th iobarbituric acid reactive products was observed (9.91 +/- 0.78 mu mol/l vs . 7.01 +/- 0.47 mu mol/l, P < 0.003). A positive correlation between thioba rbituric acid reactive products and glucose, glycated haemoglobin and fruct osamine in the serum of diabetic patients was observed. Conclusion. These findings may explain some of the mechanisms underlying th e increased susceptibility to certain infection in patients with Type 2 DM.