Studies on superoxide anion production by human monocytes Part 2. Impaired superoxide production in diabetics

Monocytes obtained from 44 diabetics were stimulated with concanavalin A and cytochalasin E, and the resulting superoxide production was assessed to see if it was affected by the degree of control of the diabetes.In controls, the O(-)(2) generation was 12.4±3.0 (mean±SD) nmol/min/10(6) cells, and in diabetics, it was 9.9±2.9, which was significantly lower than in the controls (p<0.001).Diabetic subjects were classified into three groups according to their fasting glucose levels: one, good control (FBS≦140mg/100ml); two, fair control (FBS>140mg/100ml and <200mg/100ml), and three, poor control (FBS≧200mg/100ml). These groups generated 0(-)(2) levels of 11.5±2.0, 10.0±2.2 and 8.7±3.3 nmol/min/10(6) cells. O(-)(2) generation in the poorly controled group was significantly lower than in the well controlled group (p<0.02). A negative correlation was found between 0(-)(2) production and the hemoglobin A(1) value (r=-0.48).The untreated group showed significantly lower O(-)(2) generation than the insulin treated group (p<0.01).These findings suggest that impaired O(-)(2) production, which leads to decreased bactericidal activity of monocytes, might be one of the factors which account for the high susceptibility of diabetics to infection.