Chiu J J, Wang D L, Chien S, Skalak R, Usami S
Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
J Biomech Eng. 1998 Feb;120(1):2-8. doi: 10.1115/1.2834303.
Atherosclerotic lesions tend to localize at curvatures and branches of the arterial system, where the local flow is often disturbed and irregular (e.g., flow separation, recirculation, complex flow patterns, and nonuniform shear stress distributions). The effects of such flow conditions on cultured human umbilical vein endothelial cells (HUVECs) were studied in vitro by using a vertical-step flow channel (VSF). Detailed shear stress distributions and flow structures have been computed by using the finite volume method in a general curvilinear coordinate system. HUVECs in the reattachment areas with low shear stresses were generally rounded in shape. In contrast, the cells under higher shear stresses were significantly elongated and aligned with the flow direction, even for those in the area with reversed flow. When HUVECs were subjected to shearing in VSF, their actin stress fibers reorganized in association with the morphological changes. The rate of DNA synthesis in the vicinity of the flow reattachment area was higher than that in the laminar flow area. These in vitro experiments have provided data for the understanding of the in vivo responses of endothelial cells under complex flow environments found in regions of prevalence of atherosclerotic lesions.
动脉粥样硬化病变往往定位于动脉系统的弯曲处和分支处，这些部位的局部血流常常受到干扰且不规则（例如，血流分离、再循环、复杂的血流模式以及不均匀的剪切应力分布）。通过使用垂直台阶流通道（VSF）在体外研究了这种流动条件对培养的人脐静脉内皮细胞（HUVECs）的影响。在一般曲线坐标系中，使用有限体积法计算了详细的剪切应力分布和流动结构。低剪切应力再附着区域的HUVECs通常呈圆形。相比之下，即使是逆流区域的细胞，在较高剪切应力下也会显著伸长并与流动方向对齐。当HUVECs在VSF中受到剪切时，它们的肌动蛋白应力纤维会随着形态变化而重新组织。血流再附着区域附近的DNA合成速率高于层流区域。这些体外实验为理解在动脉粥样硬化病变高发区域发现的复杂流动环境下内皮细胞的体内反应提供了数据。
