Production of superoxide and nitric oxide by granulocytes in non-insulin-dependent diabetic patients with and without diabetic nephropathy.

Production of the superoxide radical anion O2-. and the nitric oxide radical NO-. by granulocytes was studied in 14 patients with type 2 diabetes without nephropathy, 21 patients with type 2 diabetes and diabetic nephropathy, and 19 healthy subjects, both without and after stimulation with opsonized zymosan. O2-. production by both resting and stimulated granulocytes was increased in type 2 diabetes patients without nephropathy but decreased in type 2 diabetes patients with nephropathy, compared with healthy subjects. NO. generation was highly augmented in type 2 diabetes patients without nephropathy by both resting and stimulated cells; values for type 2 diabetes patients with nephropathy were intermediate between the type 2 diabetes patients without nephropathy and the healthy subjects. These data point to granulocytes as one of possible sources of oxidative stress in type 2 diabetes.