Finite Element Analysis for Sheared Vascular Endothelial Cells Using Structural Optimization Method

A finite element analysis using structural optimization method was performed to simulate the remodeling of bovine aortic endothelial cells (BAECs) under flow condition. BAECs showed marked elongation and aligned in the flow direction by exposing to a steady shear stress of 2 Pa for 24 h. An atomic force microscope (AFM) system was used to obtain cell surface topography, showing that the cell height decreased significantly from 2 .8 +/-1.0 pm to 1. 4 +/- 0 .5 pm with exposure to fluid flow. The fluorescent images of cells stained by rhodamine-phalloidin showed that control cells exhibited dense peripheral bands of actin filaments, while sheared cells exhibited centrally located actin stress fibers parallel to the flow direction. In the analysis, the two-dimensional mesh was generated based on the cell surface data measured by AFM and then elastic modulus of each element was changed in accordance with an object stress, together with update of cell shape. Numerical results showed that the cell height decreased with fluid flow and the higher elastic modulus appeared in the upstream region of the nucleus at the final step, which may correspond with cytoskeletal structure. The present analysis should be effective for elucidating the remodeling of endothelial cells.