Barber Jared O, Restrepo Juan M, Secomb Timothy W
Department of Mathematics, University of Pittsburgh, Pittsburgh, PA 15260, USA.
Cardiovasc Eng Technol. 2011 Dec 1;2(4):349-360. doi: 10.1007/s13239-011-0064-4. Epub 2011 Oct 13.
Partitioning of red blood cell (RBC) fluxes between the branches of a diverging microvessel bifurcation is generally not proportional to the flow rates, as RBCs preferentially enter the higher-flow branch. A two-dimensional model for RBC motion and deformation is used to investigate the effects of cell-cell mechanical interactions on RBC partitioning in bifurcations. The RBC membrane and cytoplasm are represented by sets of viscoelastic elements immersed in a low Reynolds number flow. Several types of two-cell interactions that can affect partitioning are found. In the most frequent interactions, a trade-off' occurs, in which a cell entering one branch causes a following cell to enter the other branch. Other types of interactions include herding,' where the leading cell is caused to enter the same branch as the following cell, and `following,' where the trailing cell is caused to enter the same branch as the leading cell. The combined effect of these cell-cell interactions is a tendency towards more uniform partitioning, which results from the trade-off effect but is reduced by the herding and following effects. With increasing hematocrit, the frequency of interactions increases, and more uniform partitioning results. This prediction is consistent with experimental observations on how hematocrit affects RBC partitioning.
在微动脉分支处，红细胞（RBC）通量在各分支之间的分配通常与流速不成比例，因为红细胞优先进入高流量分支。利用二维红细胞运动和变形模型研究细胞间机械相互作用对分支处红细胞分配的影响。红细胞膜和细胞质由浸没在低雷诺数流中的粘弹性元件集表示。发现了几种可能影响分配的双细胞相互作用类型。在最常见的相互作用中，会出现一种“权衡”现象，即进入一个分支的细胞会导致跟随其后的细胞进入另一个分支。其他类型的相互作用包括“聚集”，即引导细胞被导致与跟随细胞进入同一分支，以及“跟随”，即尾随细胞被导致与引导细胞进入同一分支。这些细胞间相互作用的综合效应是趋向于更均匀的分配，这是由权衡效应导致的，但会因聚集和跟随效应而减弱。随着血细胞比容的增加，相互作用的频率增加，分配也更趋均匀。这一预测与关于血细胞比容如何影响红细胞分配的实验观察结果一致。
