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/cm
2 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/cm
2. Also, neutrophil rolling lengths at 1 dyne/cm
2 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.
Keywords Shear stress - Inflammation - Glucocorticoid - Neutrophils