Reactive oxygen species generation by leukocytes in populations at risk for atherosclerotic disease

The aim of this study was to investigate intracellular levels of reactive oxygen species (ROS) in circulating leukocytes in populations at risk for atherosclerosis compared with in healthy individuals. The study populations consisted of 27 non-diabetic men (aged 40 - 69 years) with untreated hypercholesterolemia (HC), 13 individuals (aged 39 - 56 years) with well-controlled insulin-dependent diabetes mellitus (DM), and 20 healthy individuals (aged 26 - 61 years) (REF). Citrated whole blood was collected in fasting condition. Using flow cytometric techniques, the resting levels and the response upon phorbol 12-myristate 13-acetate (PMA, 100 ng/mL) stimulation of ROS were measured in circulating monocytes (MO) and granulocytes (GR). The relative mean fluorescence intensity (rMFI) in 10 4 leukocytes of fluorochromes mainly reflecting the levels of peroxynitrite (ONOO - ) hydrogen peroxide (H 2 O 2 ) and superoxide anion (O 2 - ) was recorded. Significantly, higher basal levels of ONOO - in GR from the combined risk population compared with REF were found (1.4 vs. 1.5 rMFI, p