Idealization of pericellular fluid space geometry and dimension results in a profound underprediction of nano-microscale stresses imparted by fluid drag on osteocytes
Idealization of pericellular fluid space geometry and dimension results in a profound underprediction of nano-microscale stresses imparted by fluid drag on osteocytes
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DOI：
10.1016/j.jbiomech.2008.02.035
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发表时间：
2008-01-01
影响因子：
2.4
通讯作者：
Tate, Melissa L. Knothe
中科院分区：
文献类型：
--
作者：
Anderson, Eric J.;Tate, Melissa L. Knothe
到目前为止，没有发表的研究已经定量研究的几何和尺寸理想化的流体阻力细胞表面所赋予的机械信号的预测效果。我们假设，这种理想化的影响的大小和范围的预计发生在亚细胞水平的力量。因此，我们使用计算流体动力学来预测实际和理想化的细胞周小管几何形状的二维和三维模型中的细胞表面上的流体速度和压力以及剪切应力的大小和空间变化。此外，基于高分辨率透射电子显微镜（TEM），对实际细胞周围空间尺寸的变化进行统计分析。占自然发生的突起的细胞周围空间划定界膜导致预测的局部应力峰值的细胞表面上，使用理想化的几何形状预测的5倍。预测占实际的细胞周围的几何形状接近那些需要在体外模型中触发细胞活性。此外，TEM为基础的尺寸的统计分析表明，小管空间的宽度以及细胞突起的直径，这两者都随着距离细胞体的增加而减少的显着变化。据我们所知，这项研究首次显示了生理几何形状本身对骨中纳米级流动状态的影响，以及生理几何形状对通过负载诱导的流体流动局部传递给细胞的力的大小和变化的深远影响。(C)2008爱思唯尔有限公司保留所有权利。
To date, no published study has examined quantitatively the effect of geometric and dimensional idealization on prediction of the mechanical signals imparted by fluid drag to cell surfaces. We hypothesize that this idealization affects the magnitude and range of imparted forces predicted to occur at a subcellular level. Hence, we used computational fluid dynamics to predict magnitudes and spatial variation of fluid velocity and pressure, as well as shear stress, on the cell surface in two- and three-dimensional models of actual and idealized pericellular canalicular geometries. Furthermore, variation in actual pericellular space dimensions was analyzed statistically based on high-resolution transmitted electron micrographs (TEM). Accounting for the naturally occurring protrusions of the pericellular space delineating lamina limitans resulted in predictions of localized stress spikes on the cell surface, up to five times those predicted using idealized geometries. Predictions accounting for actual pericellular geometries approached those required to trigger cell activity in in vitro models. Furthermore, statistical analysis of TEM-based dimensions showed significant variation in the width of the canalicular space as well as the diameter of the cell process, both of which decrease with increasing distance from the cell body. For the first time to our knowledge, this study shows the influence of physiologic geometry per se on the nano-scale flow regimes in bone, and the profound influence of physiologic geometry on force magnitudes and variations imparted locally to cells through load-induced fluid flow. (C) 2008 Elsevier Ltd. All rights reserved.