Biorheological views of endothelial cell responses to mechanical stimuli.
Biorheological views of endothelial cell responses to mechanical stimuli.
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作者：
Masaaki Sato;T. Ohashi
血管内皮细胞位于血管壁的最内层，并且总是暴露于三种不同的机械力：由于血流的剪切应力、由于血压的静水压力和由于血管变形的周期性拉伸。众所周知，内皮细胞对这些机械力作出反应并改变其形状、细胞骨架结构和功能。本文主要就剪切力和静水压力对内皮细胞形态的影响作一综述。在施加流体剪切应力后，培养的内皮细胞显示出明显的伸长和在流动方向上的取向。此外，肌动蛋白丝的粗应力纤维出现并沿细胞长轴沿着。因此，内皮细胞形态与细胞骨架结构密切相关。此外，形态变化的动态过程中显示和相关的事件，如机械刚度和功能的变化也进行了总结。当内皮细胞暴露于静水压力，他们表现出显着的伸长率和方向在一个随机的方向，连同发展的中心位置，厚应力纤维。压力内皮细胞也表现出一个多层的结构与较少的表达VE-钙粘蛋白不像在控制条件。同时加载的静水压力和剪切应力抑制内皮细胞多层和诱导伸长和定向的内皮细胞与发达的VE-钙粘蛋白在一个单层，这表明，为了更好地了解血管内皮细胞的反应，必须考虑到不同的机械力的组合，如存在于体内的机械条件下。
Vascular endothelial cells are located at the innermost layer of the blood vessel wall and are always exposed to three different mechanical forces: shear stress due to blood flow, hydrostatic pressure due to blood pressure and cyclic stretch due to vessel deformation. It is well known that endothelial cells respond to these mechanical forces and change their shapes, cytoskeletal structures and functions. In this review, we would like to mainly focus on the effects of shear stress and hydrostatic pressure on endothelial cell morphology. After applying fluid shear stress, cultured endothelial cells show marked elongation and orientation in the flow direction. In addition, thick stress fibers of actin filaments appear and align along the cell long axis. Thus, endothelial cell morphology is closely related to the cytoskeletal structure. Further, the dynamic course of the morphological changes is shown and the related events such as changes in mechanical stiffness and functions are also summarized. When endothelial cells were exposed to hydrostatic pressure, they exhibited a marked elongation and orientation in a random direction, together with development of centrally located, thick stress fibers. Pressured endothelial cells also exhibited a multilayered structure with less expression of VE-cadherin unlike under control conditions. Simultaneous loading of hydrostatic pressure and shear stress inhibited endothelial cell multilayering and induced elongation and orientation of endothelial cells with well-developed VE-cadherin in a monolayer, which suggests that for a better understanding of vascular endothelial cell responses one has to take into consideration the combination of the different mechanical forces such as exist under in vivo mechanical conditions.