Effects of wall shear stress and fluid recirculation on the localization of circulating monocytes in a three-dimensional flow model.
Effects of wall shear stress and fluid recirculation on the localization of circulating monocytes in a three-dimensional flow model.
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DOI：
10.1016/0021-9290(95)00094-1
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发表时间：
1995-12
影响因子：
2.4
通讯作者：
William F. Pritchard;Peter F. Davies;Z. Derafshi;D. Polacek;R. Tsao;Randall O. Dull;Steven A. Jones;Don P. Giddens
中科院分区：
文献类型：
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作者：
William F. Pritchard;Peter F. Davies;Z. Derafshi;D. Polacek;R. Tsao;Randall O. Dull;Steven A. Jones;Don P. Giddens
早期动脉粥样硬化病变的位置与这些部位的血流动力学特征之间存在相关性。循环单核细胞是动脉粥样硬化斑块发病的关键细胞，定位于动脉粥样硬化发生的部位。单核细胞粘附到血管壁的分布部分由血流动力学因素决定的假设，通过在模型壁上没有任何生物活性的体外流动模型中研究单核细胞粘附来解决。将U937细胞悬浮液（Re = 200）灌注到有狭窄的轴对称硅胶流动模型中，然后进行反向步骤。该模型提供了空间变化的壁面剪应力、流动分离和再附着以及三维流动模式。通过视频显微照片分析细胞滚动速度和粘附率。通过对流体运动方程的数值求解，得到了壁面剪应力。在趋化肽梯度存在的情况下，也研究了细胞粘附模式。胞体轧制速度随胞壁剪切应力呈线性变化。黏附率随局部壁面剪应力的增大而减小，但也受径向速度分量、再循环区动力学和流动再附着的影响。在扩张位点下游的趋化肽源附近，粘附性增加。人单核细胞的实验结果与U937实验在质量上相似。U937细胞粘附率的差异仅作为流场流体动力学特性的函数，在模型壁上没有任何生物活性的情况下清楚地证明了这一点。
There is a correlation between the location of early atherosclerotic lesions and the hemodynamic characteristics at those sites. Circulating monocytes are key cells in the pathogenesis of atherosclerotic plaques and localize at sites of atherogenesis. The hypothesis that the distribution of monocyte adhesion to the vascular wall is determined in part by hemodynamic factors was addressed by studying monocyte adhesion in an in vitro flow model in the absence of any biological activity in the model wall. Suspensions of U937 cells were perfused (Re = 200) through an axisymmetric silicone flow model with a stenosis followed by a reverse step. The model provided spatially varying wall shear stress, flow separation and reattachment, and a three-dimensional flow pattern. The cell rolling velocity and adhesion rates were determined by analysis of videomicrographs. Wall shear stress was obtained by numerical solution of the equations of fluid motion. Cell adhesion patterns were also studied in the presence of chemotactic peptide gradients. The cell rolling velocity varied linearly with wall shear stress. The adhesion rate tended to decrease with increasing local wall shear stress, but was also affected by the radial component of velocity and the dynamics of the recirculation region and flow reattachment. Adhesion was increased in the vicinity of chemotactic peptide sources downstream of the expansion site. Results with human monocytes were qualitatively similar to the U937 experiments. Differences in the adhesion rates of U937 cells occurring solely as a function of the fluid dynamic properties of the flow field were clearly demonstrated in the absence of any biological activity in the model wall.