Increase in glycaemia stimulates reactive oxygen species (ROS) production by polymorphonuclear neutrophils in type 2 diabetic patients

Polymorphonuclear neutrophils (PMNs), oxidative stress and hyperglycaemia play important roles in the development of microand macroangiopathy in diabetes. The aim of this study was to evaluate the infl uence of a meal and the increment of postprandial glycaemia on reactive oxygen species production by PMNs in type 2 diabetic patients. The study was performed on 25 patients – 18 women and 7 men, aged 61.7+10.5 years, diagnosed with type 2 diabetes for 16.0+7.5 years, and in 20 healthy control subjects. PMNs were isolated from the blood by single-step gradient centrifugation. The superoxide anion (O2 -) production by PMNs was measured spectrophotometrically by cytochrome C reduction, and the hydrogen peroxide (H2O2) level was measured spectrophotometrically by phenyl red oxidation. A signifi cant correlation was observed between an increase in glycaemia and O2 production (r=0.52, p<0.05) and in H2O2 production by PMNs (r=0.43, p<0.05). The results obtained suggest that in obese type 2 diabetic patients it is the increment of postprandial glycaemia, and not directly the meal itself, that stimulates reactive oxygen species production by PMNs. This might play an important role in the development of late vascular complications and thus have clinical implications.