[Simulation of the deformation of the endothelial cell under a shear flow].

The coupling between the endothelium and blood flow is an important biomedical problem and has drawn extensive research. Endothelial cells are known to adapt their shapes and functions in response to applied shear flow. Shear Stress being regarded as a primary triggering signal for cellular remodeling, it is important to understand the interaction mechanism between applied shear flow and endothelial cells. In present study we have established a theoretical model to simulate the coupling between the deformation of an endothelial cell and applied shear flow. A two dimensional computational fluid dynamic (CFD) is conducted to determine the local distributions of mechanical stress and pressure on cell surface. Our results show that: (1) the deformation of endothelial cell changes with alpha (corresponding to the shear stress imposed on cell surface by flow fluid). When alpha is greater than 0.021, the cell deformability increases greatly; (2) the distributions of stress and pressure on cell surface are not uniform, but the maximal shear stress and displacement are always at the top point of the cell. Meanwhile, we have measured the deformation of cultured human aortic endothelial cells (HAECs) exposed to shear flow by using a flow chamber. We found that the numerical results are well consistent with those of experiment. These results suggest that the non-uniformity distributions of mechanical stress and pressure on cell surface may play a particular role in the mechanism of cell activation and in the regulation of endothelial cells functions (modification of cytoskeleton, distributions of adhesion molecules, etc.). The present study offers a framework to facilitate the development of a comprehensive dynamic model for endothelial cells.