State Key Laboratory of Fluid Power and Mechatronic Systems, Department of Engineering Mechanics, and Center for X-Mechanics, <a href="https://ror.org/00a2xv884">Zhejiang University</a>, Hangzhou 310027, China.
Phys Rev E. 2024 Sep;110(3-1):034409. doi: 10.1103/PhysRevE.110.034409.
The endothelial glycocalyx layer (EGL) plays a crucial role in regulating blood flow in microvessels. Experimental evidence suggests that there is greater blood flow resistance in vivo compared to in vitro, partially due to the presence of the EGL. However, the complex relationship between EGL deformation and blood cell behavior in shear flow and its quantification remains incompletely understood. To address this gap, we employ a particle-based numerical simulation technique to examine the interaction of the EGL with flowing red blood cells (RBCs) in microtubes. We examine changes in EGL deformation in response to variations in shear rate, EGL graft density, and contour height. Our results indicate that the alterations in EGL height are influenced by the mechanical properties of the EGL, flow conditions, and the RBC-EGL interaction. The flowing RBC compresses the EGL, causing a notable reduction in EGL height near the RBC flow. Additionally, we find that the presence of the EGL in the microtube results in increased RBC deformation and a wider gap between the RBC and tube wall due to spatial occupancy. The significant impact of the EGL on RBC flow is particularly evident in microtubes with diameters ranging from 7 to 10µm, a range consistent with notable differences in vascular flow resistance observed between in vivo and in vitro experiments. The simulation results shed insight on the dynamic interplay between RBC and the EGL in microvascular blood flow.
内皮糖萼层（EGL）在调节微血管中的血流起着至关重要的作用。实验证据表明，与体外相比，体内的血流阻力更大，部分原因是存在 EGL。然而，EGL 变形与剪切流中血细胞行为之间的复杂关系及其定量仍然不完全清楚。为了解决这一差距，我们采用基于粒子的数值模拟技术来研究 EGL 与微管中流动的红细胞（RBC）之间的相互作用。我们研究了 EGL 变形对剪切率、EGL 接枝密度和轮廓高度变化的响应。我们的结果表明，EGL 高度的变化受 EGL 的力学特性、流动条件和 RBC-EGL 相互作用的影响。流动的 RBC 压缩 EGL，导致在 RBC 流动附近 EGL 高度明显降低。此外，我们发现，由于空间占据，微管中的 EGL 会导致 RBC 变形增加和 RBC 与管壁之间的间隙变宽。EGL 对 RBC 流动的显著影响在直径为 7 至 10μm 的微管中尤为明显，这与体内和体外实验中观察到的血管流动阻力显著差异的范围一致。模拟结果深入了解了 RBC 和 EGL 在微血管血流中的动态相互作用。
