Description: Fluid shear stress and circumferential stretch play important roles in maintaining the homeostasis of the blood vessel, and they can also be pathophysiological factors in cardiovascular diseases such as atherosclerosis and hypertension. Some of the effects of mechanical strain on endothelial cells are similar to those by shear stress, eg, the signaling pathways and the genes activated, but there are differences, eg, the time course of the responses. Studies on the effects of mechanical forces on signal transduction and gene expression provide insights into the molecular mechanisms by which hemodynamic factors regulate vascular physiology and pathophysiology.