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 2 DM and 20 nondiabetic controls provided blood samples for analysis.

Results: The superoxide dismutase (SOD) activity was lower by 41% in polymorphonuclear 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<0.005). Glutathione peroxidase (GSHPx) and glutathione reductase (GR) activities 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<0.003, and 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 difference. A significant increase (141.37% of control) in the concentration of thiobarbituric acid reactive products was observed (9.91+/-0.78 miromol/l vs. 7.01+/-0.47 micromol/l, P<0.003). A positive correlation between thiobarbituric acid reactive products and glucose, glycated haemoglobin and fructosamine in the serum of diabetic patients was observed.

Conclusion: These findings may explain some of the mechanisms underlying the increased susceptibility to certain infection in patients with Type 2 DM.