Cellular Recognition and Transduction of Fluid Mechanical Shear Stress Signals

Abstract

Hemodynamic forces associated with blood flow provide an important potential influence on both the physiology and pathophysiology of the cardiovascular system. As the lining of the entire cardiovascular system, the endothelium is uniquely positioned to be the sensor, responder, and transducer of these hemodynamic signals. A major component of the hemodynamic forces which impact upon the vascular endothelium is fluid-imposed wall shear stress. Since the magnitude of this shear stress is dependent upon both the velocity of blood flow across the endothelial surface as well as the geometry of the vascular bed, the shear stress magnitude experience by endothelium varies greatly even within a specific vascular segment. For example, the endothelium residing within the branch points of the abdominal aorta experience much different wall shear stress levels than endothelium residing in straight channels of the same vessel. It is this diversity of shear stress and its correlation with focal differences in arterial physiology and pathology, that has led to the hypothesis that hemodynamic shear stress may modulate the physiology of the vascular wall as well as play a key role in the pathogenesis of diseases such as atherosclerosis.