Cellular responses to mechanical stress

Virtually all cells accommodate or respond to the mechanical environment. The responses of endothelium to externally-generated forces such as those associated with blood flow is a useful paradigm for mechanical stress mechanisms in cells in general. In the case of the endothelium there are important physiological and pathological cardiovascular consequences related to endothelial biomechanical properties. I will review the concepts of flow-mediated mechanotransduction in endothelium, particularly studies conducted in vitro. The concept of intrinsic cell tension and its modification by an external load will be considered within the realm of direct displacement of a mechanical sensing system in endothelium. This will be contrasted with the generation of flow-mediated responses by changes in the local concentrations of potent chemicals at the cell membrane, an indirect mechanism of flow signalling that may or may not require coordinate effects of direct forces acting on the cell, such as shear stress. State-of-the-art techniques to measure the surface features of endothelial cells as they pertain to the distribution of flow forces will be presented.