Barbee K A, Mundel T, Lal R, Davies P F
Department of Pathology, Mathematics, University of Chicago, Illinois 60637, USA.
Am J Physiol. 1995 Apr;268(4 Pt 2):H1765-72. doi: 10.1152/ajpheart.1995.268.4.H1765.
The stresses acting on the luminal surface of endothelial cells due to shear flow were determined on a subcellular scale. Atomic force microscopy was used to measure the surface topography of confluent endothelial monolayers cultured under no-flow conditions or exposed to steady shear stress (12 dyn/cm2 for 24 h). Flow over these surface geometries was simulated by computational fluid dynamics, and the distribution of shear stress on the cell surface was calculated. Flow perturbations due to the undulating surface produced cell-scale variations of shear stress magnitude and hence large shear stress gradients. Reorganization of the endothelial surface in response to prolonged exposure to steady flow resulted in significant reductions in the peak shear stresses and shear stress gradients. From the relationship between surface geometry and the resulting shear stress distribution, we have defined a hydrodynamic shape factor that characterizes the three-dimensional morphological response of endothelial cells to flow. The analysis provides a complete description of the spatial distribution of stresses on individual endothelial cells within a confluent monolayer on a scale relevant to the study of physical mechanisms of mechanotransduction.
在亚细胞尺度上测定了剪切流作用于内皮细胞管腔表面的应力。利用原子力显微镜测量在无流动条件下培养或暴露于稳定剪切应力（12达因/平方厘米，持续24小时）的汇合内皮单层的表面形貌。通过计算流体动力学模拟这些表面几何形状上的流动，并计算细胞表面的剪切应力分布。由于起伏表面引起的流动扰动产生了细胞尺度的剪切应力大小变化，从而产生了大的剪切应力梯度。内皮表面对长时间稳定流动的响应重组导致峰值剪切应力和剪切应力梯度显著降低。根据表面几何形状与由此产生的剪切应力分布之间的关系，我们定义了一个流体动力学形状因子，该因子表征了内皮细胞对流动的三维形态响应。该分析完整描述了汇合单层中单个内皮细胞上应力的空间分布，其尺度与机械转导物理机制的研究相关。
