Motion of red blood cells in a capillary with an endothelial surface layer: effect of flow velocity
Motion of red blood cells in a capillary with an endothelial surface layer: effect of flow velocity
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DOI：
10.1152/ajpheart.2001.281.2.h629
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发表时间：
2001-08-01
影响因子：
4.8
通讯作者：
Pries, AR
中科院分区：
文献类型：
--
作者：
Secomb, TW;Hsu, R;Pries, AR
毛细血管的内表面衬有大分子，形成内皮表面层（ESL）。使用理论模型研究流速对具有 ESL 的毛细血管中红细胞运动和轴对称变形的影响。分析细胞变形，包括膜剪切和弯曲弹性的影响。使用润滑理论计算细胞周围和通过 ESL 的等离子体流。 ESL 表现为多孔层，对穿透它的红细胞施加压力。根据该模型，细胞周围的血浆流产生的流体动力压力将移动的红细胞挤压成狭窄的细长形状。如果ESL宽度为0.7μm，水力电阻率为2×10(8)dyn.s.cm(-4)，并施加20dyn/cm(2)的力，则预测的红细胞与毛细血管壁之间的间隙宽度随流速的变化与观察结果非常吻合。速度为 0.1 mm/s 时的预测间隙与 0.6 mm/s 相似，而在没有 ESL 的情况下与 0.2 mm 相似。预测的流阻在低速时显着增加。该模型表明，血浆流过 ESL 时产生的流体动力会将红细胞排除在流动的毛细血管中的 ESL 之外。
Interior surfaces of capillaries are lined with macromolecules forming an endothelial surface layer (ESL). A theoretical model is used to investigate effects of flow velocity on motion and axisymmetric deformation of red blood cells in a capillary with an ESL. Cell deformation is analyzed, including effects of membrane shear and bending elasticity. Plasma flow around the cell and through the ESL is computed using lubrication theory. The ESL is represented as a porous layer that exerts compressive forces on red blood cells that penetrate it. According to the model, hydrodynamic pressures generated by plasma flow around the cell squeeze moving red blood cells into narrow elongated shapes. If the ESL is 0.7 mum wide, with hydraulic resistivity of 2 x 10(8) dyn.s.cm(-4), and exerts a force of 20 dyn/cm(2), predicted variation with flow velocity of the gap width between red blood cell and capillary wall agrees well with observations. Predicted gap at a velocity of 0.1 mm/s is similar to0.6 mum vs. similar to0.2 mm with no ESL. Predicted flow resistance increases markedly at low velocities. The model shows that exclusion of red blood cells from the ESL in flowing capillaries can result from hydrodynamic forces generated by plasma flow through the ESL.