SHEAR-DEPENDENCE OF ENDOTHELIAL FUNCTIONS

Endothelial cells are subjected to shear forces which influence import ant cell functions. Shear stress induces cell elongation and formation of stress fibers, increases permeability, pinocytosis and lipoprotein internalization, is involved in the formation of atherosclerotic lesi ons, increases the production of tissue plasminogen activator, and enh ances von Willebrand factor release and hence platelet aggregation. It decreases adherence of erythrocytes and leukocytes, and increases the release of prostacyclin, endothelium derived relaxing factor, histami ne and other compounds, but decreases erythropoietin secretion. The me chanism of signal transduction to the endothelial cell is not known ex actly; shear-sensitive ion channels seem to be involved. It is conclud ed that a better understanding of shear-dependent endothelial function s will influence pathophysiologic concepts and therapeutic interventio ns.