Hao Yinjing, Lü Shouqin, Li Wang, Long Mian, Cui Yuhong
Department of Mechanics, Tianjin University, Tianjin 300072, China.
Biomicrofluidics. 2022 Oct 27;16(5):054110. doi: 10.1063/5.0100911. eCollection 2022 Sep.
In fatty liver diseases, such as liver fibrosis and liver cirrhosis, blood flow in hepatic sinusoids, an elementary building block of the liver lobule, tends to bypass through collateral vessels inside sinusoids and presents distinct sinusoidal flows compared to normal physiological flows. It remains unclear in those flow characteristics in branched sinusoids and the correlation of pathological flows with liver lesions, mainly due to the difficulty of direct hemodynamics measurements in the sinusoids. Here, we developed a dual-branched theoretical model of hepatic sinusoidal flow to elucidate the relevant flow dynamics and mass transport. Numerical simulations, based on the lattice Boltzmann method, indicated that the flow velocity distribution in hepatic sinusoids is mainly dominated by endothelium permeability and presents a non-monotonic variation with the permeability at the fusion segment of these branched sinusoids. Flow-induced shear stress on the endothelium at the side of the Disse space exhibited a biphasic pattern, yielding a low shear stress region at the junctional site. Meanwhile, a highly polarized distribution of lipoproteins concentration was also presented at the low shear stress region, indicating a localized accumulation of typical hepatic serum proteins. Thus, this work provides the basic understanding of blood flow features and mass transport regulations in branched hepatic sinusoids.
在诸如肝纤维化和肝硬化等脂肪肝疾病中，肝小叶的基本组成部分肝血窦中的血流往往会绕过血窦内的侧支血管，与正常生理血流相比呈现出独特的血窦血流。目前尚不清楚分支血窦中的这些血流特征以及病理血流与肝脏病变之间的相关性，主要原因是在血窦中进行直接血流动力学测量存在困难。在此，我们构建了一个肝血窦血流的双分支理论模型，以阐明相关的流动动力学和物质传输。基于格子玻尔兹曼方法的数值模拟表明，肝血窦中的流速分布主要受内皮通透性的影响，并且在这些分支血窦的融合段，流速随通透性呈现非单调变化。狄氏间隙一侧内皮上的流动诱导剪切应力呈现双相模式，在连接部位产生一个低剪切应力区域。同时，在低剪切应力区域还呈现出脂蛋白浓度的高度极化分布，表明典型肝血清蛋白存在局部积累。因此，这项工作为分支肝血窦中的血流特征和物质传输规律提供了基本认识。
