Hemodynamic Forces Induce the Release of Nitric Oxide from Aortic Endothelium: Combined Effect of Shear Stress and Pressure

Abstract

Introduction : Fluid shear stress (pulsatile and laminar) and pressure comprise of the two in vivo physical forces to which vascular endothelium is constantly exposed. Besides, vasodilator and autacoids, nitric oxide is the main endothelium derived relaxing factor (EDRF) released in response to alterations in blood pressure and shear stress, which constitute hemodynamic stress.The aim of the present study was to study the effect of pulsatile/laminar shear stress on endothelial nitric oxide production . Methodology: A perfusion system was used to study the effect of shear stress on endothelialnitic oxide production. It was designed as a close continuous flow loop in which the pressure was superimposed with flow through a pressure head with adjustable height. Results: At hydrostatic pressure of 70 cm water (normotensive condition) and at 150 cm water (hypertensive condition), an increase in nitric oxide concentration was observed. The increase was 10 fold higher at 150 cm with respect to static values than the increase observed at 70 cm ofwater. Conclusion: Laminar shear stress and pressure induce the release of endothelial nitric oxide, which may aid to understand the role of wall shear stress during arterial resistance in hypertension.

Keywords

• Not available