ABSTRACT
Our laboratory and others have been rigorously studying the influence of mechanical forces on endothelial cell biology. It has been our contention that static conditions commonly utilized to study endothelial cells in culture may not reflect their in vivo milieu. Endothelial cells in vivo are subjected to a variety of flow-related forces including shear stress, hydrostatic pressure, and cyclic strain (1-2). Shear stress is the tangential stress applied across the endothelial cell surface due to the bulk flow of blood. Hydrostatic pressure is the normal stress acting radially on the vessel wall due to the propagation of the pressure wave. Cyclic strain represents the stress acting along the vessel wall due to circumferential deformation. Endothelial cells are exposed to all three forces whereas the underlying smooth muscle cells are exposed to hydrostatic pressure and cyclic strain. There are a several reviews of the effects of shear stress on endothelial cells in this text (see Chapters XX). Therefore, we will mention shear studies briefly and solely for comparison purposes to that of cyclic strain.
