[Shear stress and vascular formation].

Blood flow plays important roles in the morphogenesis of blood vessels. For instance, increases in blood flow induce dilatation of the blood vessels, while decreases in blood flow cause reduction of vessel diameter. Blood flow also stimulates angiogenesis. In these blood flow-dependent phenomena, wall shear stress generated by flowing blood that acts on vascular endothelial cells works as a key factor. Numerous in vivo and in vitro studies have demonstrated that mechanical forces, shear stress, actually modulate the morphology and many functions of endothelial cells, and these forces also alter their gene expression. More recently, a cis-acting shear stress responsive element was identified in the promoters of endothelial genes that respond to shear stress, suggesting a common mechanism linking biomechanical forces to gene expression. Details of the process in which shear stress-mediated changes in endothelial cell functions lead to vascular remodeling and angiogenesis, however, are not entirely clear. Elucidation of this problem will give us not only a better understanding of the morphogenesis of blood vessels but also new therapies that can help manage or prevent cardiovascular diseases including atherosclerosis.