Davies P F, Mundel T, Barbee K A
Department of Pathology, University of Chicago, IL 60637, USA.
J Biomech. 1995 Dec;28(12):1553-60. doi: 10.1016/0021-9290(95)00102-6.
Exposure of endothelium to a nominally uniform flow field in vivo and in vitro frequently results in a heterogeneous distribution of individual cell responses. Extremes in response levels are often noted in neighboring cells. Such variations are important for the spatial interpretation of vascular responses to flow and for an understanding of mechanotransduction mechanisms at the level of single cells. We propose that variations of local forces defined by the cell surface geometry contribute to these differences. Atomic force microscopy measurements of cell surface topography in living endothelium both in vitro and in situ combined with computational fluid dynamics demonstrated large cell-to-cell variations in the distribution of flow-generated shear stresses at the endothelial luminal surface. The distribution of forces throughout the surface of individual cells of the monolayer was also found to vary considerably and to be defined by the surface geometry. We conclude that the endothelial three-dimensional surface geometry defines the detailed distribution of shear stresses and gradients at the single cell level, and that there are large variations in force magnitude and distribution between neighboring cells. The measurements support a topographic basis for differential endothelial responses to flow observed in vivo and in vitro. Included in these studies are the first preliminary measurements of the living endothelial cell surface in an intact artery.
在体内和体外，内皮细胞暴露于名义上均匀的流场中时，常常会导致单个细胞反应的异质分布。在相邻细胞中经常会观察到反应水平的极端差异。这种变化对于血管对血流反应的空间解释以及理解单细胞水平的机械转导机制很重要。我们提出，由细胞表面几何形状定义的局部力的变化是造成这些差异的原因。结合计算流体动力学，对体外和原位活体内皮细胞表面形貌进行的原子力显微镜测量表明，在内皮腔表面，流动产生的剪切应力分布存在很大的细胞间差异。还发现单层单个细胞整个表面的力分布差异很大，且由表面几何形状决定。我们得出结论，内皮细胞的三维表面几何形状决定了单细胞水平上剪切应力和梯度的详细分布，并且相邻细胞之间的力大小和分布存在很大差异。这些测量结果支持了在体内和体外观察到的内皮细胞对血流差异反应的地形学基础。这些研究还包括对完整动脉中活体内皮细胞表面的首次初步测量。
