Under fluid shear stress, applied both in vivo and in vitro, vascular endothelial cells show morphological changes. After applying shear stress, cultured endothelial cells showed elongation and orientation to the flow direction (Kataoka et al., 1998). Moreover, statistical image analysis showed that intercellular F-actin distributions were confirmed to change depending on the shear stress and the flow direction. Thus, the endothelial cell morphology relates closely with the cytoskeletal structures. Intercellular stress distributions in the cells may be also accompanied by the reorganization of cytoskeletal structures. The use of both atomic force microscopy measurements (AFM) of endothelial cell surface topography and computational fluid dynamics of shear stress distributions acting on the cell surface, it has revealed that the surface geometry defined the detailed distribution of shear stress (Davies et al., 1995).