Nitric Oxide Production by Monocytes in Children with OSA and Endothelial Dysfunction.

Obstructive sleep apnea (OSA) is associated with a higher risk for alterations in endothelial post-occlusive hyperemia, an eNOS-dependent response. However, since not all children manifest endothelial dysfunction (ED), we hypothesized that differences in circulating monocyte subsets and nitric oxide production may underlie the vascular phenotype in pediatric OSA. Matched pre-pubertal children with OSA with (OSAab) and without ED (OSAn), and controls (CO) were recruited. Peripheral blood mononuclear cells were subtyped into CD14+ and CD16+ cells, and nitric oxide (NO) production was assessed using flow cytometry. ED was defined as time to reach maximal reperfusion (Tmax) >45 sec by laser Doppler flowmetry. 11 OSAab, 12 OSAn, and 12 CO matched children completed the study. OSAab had increased CD16+ and decreased CD14+ cell numbers. They also had increased CX3CR1 expression in CD16+ monocytes (p<0.01). Furthermore, monocytes from OSAab exhibited overall reduced NO production (787±71 vs. 1226±229 and 1089±116 median fluorescence intensity units in OSAn and CO, respectively; p<0.01). Significant bivariate associations emerged between NO production, monocyte subsets, CX3CR1 in CD16+ monocytes, CD14+/CD16+ and Tmax. Thus, OSA in children is associated with increased numbers of pro-inflammatory monocytes and reduced NO production in circulating monocytes that are closely associated with endothelial ...
Source: Clinical Science - Category: Biomedical Science Authors: Source Type: research