A macromolecule transport model for the arterial wall and endothelium based on the ultrastructural specialization observed in electron microscopic studies
A macromolecule transport model for the arterial wall and endothelium based on the ultrastructural specialization observed in electron microscopic studies
复制标题
基于电子显微镜研究中观察到的超微结构专业化的动脉壁和内皮的大分子运输模型
DOI：
10.1017/s0022112076001973
复制
发表时间：
1976
影响因子：
3.7
通讯作者：
C. Caro
中科院分区：
文献类型：
--
作者：
S. Weinbaum;C. Caro
提出了动脉壁的复合流体动力学扩散模型，用于描述相对惰性大分子穿过人类和动物大动脉内皮层的囊泡运输以及它们随后在内膜和中膜的底层组织中的扩散。该模型的动机是在电子显微镜研究中观察到的动脉壁高度专业化的超微结构，以及最近在仔细控制的体外条件下对动物动脉中标记大分子的时间依赖性吸收的实验测量。所提出的跨内皮细胞层囊泡运输的动态模型考虑了 700 Å 囊泡的受限布朗扩散，受到与内皮细胞质膜的长程流体动力学和短程伦敦-范德华力相互作用。使用类似边界层的方法开发了质膜附近和细胞内部的运动和稳态囊泡密度分布的近似解。刚刚描述的囊泡运输模型在底层组织的基本扩散模型中表现为一种新颖的边界条件。后者被视为由间质液连续体和均匀分散的平滑肌相组成的两相介质，如 Hills (1968) 首次提出的。该底层组织模型假设平滑肌细胞对大分子穿过动脉壁的扩散贡献不大，但由于其体积分数大，因此在大扩散时间内充当大分子的主要储存库。理论模型中出现的无量纲参数是通过将时间依赖性总壁摄取的解与 Fry (1973) 的犬颈动脉实验数据进行比较来确定的。
A composite hydrodynamic-diffusion model of the arterial wall is presented to describe the vesicular transport of relatively inert macromolecules across the inner endothelial lining of the larger arteries of humans and animals and their subsequent diffusion in the underlying tissue of the intima and media. This model is motivated by the highly specialized ultrastructure of the arterial wall observed in electron microscopic studies and the recent experimental measurements of the time-dependent uptake of labelled macromolecules in animal arteries under carefully controlled in vitro conditions. The proposed dynamic model for the vesicular transport across the endothelial cell layer considers the constrained Brownian diffusion of 700 Å vesicles subject to long-range hydrodynamic and short-range London-van der Waals force interactions with the plasmalemma membranes of the endothelial cell. Approximate solutions are developed for the motion and the steady-state vesicle density distribution near the plasmalemma and in the interior of the cell using boundary-layer-like methods. The model for the vesicular transport just described appears as a novel boundary condition in the basic diffusion model for the underlying tissue. The latter is treated as a two-phase medium comprised of an interstitial fluid continuum with a uniformly dispersed smooth muscle phase as first proposed by Hills (1968). This model for the underlying tissue assumes that the smooth muscle cells contribute insignificantly to the macromolecule diffusion across the arterial wall but act as the principal storage reservoir for the macromolecules for large diffusion times because of their large volume fraction. The dimensionless parameters that arise in the theoretical model are determined by comparing the solutions for the time-dependent total wall uptake with Fry's (1973) experimental data for canine carotid artery.