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

Abstract

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 (H2O2) and superoxide anion (O2-) 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<0.05). Upon PMA stimulation, significantly lower levels of O2 in GR in the risk populations compared to REF (119 vs. 90 Si, p<0.001) were observed. In conclusion, increased resting levels of ROS in circulating granulocytes, but reduced response to PMA stimulation could be demonstrated in populations at risk for atherosclerosis compared with in healthy individuals. This might indicate a higher degree of resting oxidative reactions, with partly exhausted cells and less capacity to host defence.

Structure–function alteration of hemoglobin in arsenicosis patients: a probable pathway to exert toxicity

“…Peroxidative activity of Hb was measured (Table ) and found to be increased in the chronic arsenicosis patients compared with normal healthy controls, indicating altered oxidative status of Hb in diseased condition. Altered peroxidative activity suggests probable structural alteration of Hb as a result of chemical modification due to reactive oxygen species generated in disease pathology (Saha et al , ; Milton, ; Eid et al , ). In the stressed condition oxyhemoglobin rapidly oxidizes to methemoglobin in the presence of low concentrations of hydrogen peroxide.…”

The Nitric Oxide-Donating Pravastatin Derivative, NCX 6550 [(1S-[1α(βS*, δS*), 2α, 6α, 8β-(R*), 8aα]]-1,2,6,7,8,8a-Hexahydro-β, δ, 6-trihydroxy-2-methyl-8-(2-methyl-1-oxobutoxy)-1-naphtalene-heptanoic Acid 4-(Nitrooxy)butyl Ester)], Reduces Splenocyte Adhesion and Reactive Oxygen Species Generation in Normal and Atherosclerotic Mice

“…Our observation that splenocytes from ApoEϪ/Ϫ mice similarly generate substantially greater amounts of ROS is, to our knowledge, the first demonstration of this phenomenon, although the relative contribution of each cell type in the splenocyte suspensions to the total CL signal is unknown. Elevated ROS generation from leukocytes has been described in obese (Dandona et al, 2001) and type II diabetic (Orie et al, 2000) patients, but data from patients with atherosclerosis are conflicting (Araujo et al, 1995;Eid et al, 2002). ROS generation by monocytes and neutrophils in disease models is well established, but evidence is now mounting that T lymphocytes also generate ROS (Williams and Kwon, 2004), for example, by the lipoxygenase pathway (Los et al, 1995), mitochondrial electron transport chain (Griendling et al, 2000), or NOX-based NAD(P)H oxidases (Lambeth, 2004), although there is no information regarding the effect of hypercholesterolemia on these systems.…”