Hemodynamic Regulation of Inflammation at the Endothelial–Neutrophil Interface
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- Ji, J.Y., Jing, H. & Diamond, S.L. Ann Biomed Eng (2008) 36: 586. doi:10.1007/s10439-008-9465-4
Arterial shear stress can regulate endothelial phenotype. The potential for anti-inflammatory effects of shear stress on TNFα-activated endothelium was tested in assays of cytokine expression and neutrophil adhesion. In cultured human aortic endothelial cells (HAEC), arterial shear stress of 10 dyne/cm2 blocked by >80% the induction by 5 ng/mL TNFα of interleukin-8 (IL-8) and IL-6 secretion (50 and 90% reduction, respectively, in the presence of nitric oxide synthase antagonism with 200 μM nitro-l-arginine methylester, l-NAME). Exposure of TNFα-stimulated HAEC to arterial shear stress for 5 h also reduced by 60% (p < 0.001) the conversion of neutrophil rolling to firm arrest in a venous flow assay conducted at 1 dyne/cm2. Also, neutrophil rolling lengths at 1 dyne/cm2 were longer when TNFα-stimulated HAEC were presheared for 5 h at arterial stresses. In experiments with a synthetic promoter that provides luciferase induction to detect cis interactions of glucocorticoid receptor (GR) and NFκB, shear stress caused a marked 40-fold induction of luciferase in TNFα-treated cells, suggesting a role for GR pathways in the anti-inflammatory actions of fluid shear stress. Hemodynamic force exerts anti-inflammatory effects on cytokine-activated endothelium by attenuation of cytokine expression and neutrophil firm arrest.