Intimal and medial contributions to the hydraulic resistance of the arterial wall at different pressures: a combined computational and experimental study.
Intimal and medial contributions to the hydraulic resistance of the arterial wall at different pressures: a combined computational and experimental study.
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DOI：
10.1098/rsif.2016.0234
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发表时间：
2016-06
期刊：
影响因子：
--
通讯作者：
Weinberg PD
中科院分区：
文献类型：
--
作者：
Chooi KY;Comerford A;Sherwin SJ;Weinberg PD
动脉内膜和中层的水力阻力决定了水的流量和大分子进入和穿过动脉壁的平流。尽管有一些实验和计算研究，但这些传输过程及其对跨壁压力的依赖仍然不完全清楚。在这里，我们使用实验和计算相结合的方法来确定大鼠腹主动脉的水力通透性如何依赖于这两层，以及在压力下介质的结构重排如何影响它。体外实验测定了全壁的电导、中膜的厚度、中膜平滑肌细胞(SMCs)和细胞外基质(ECM)的几何形状。用数值方法计算了流经介质的水通量。内膜值通过减法得到。发现了一种调节压力引起的中层运输特性变化的机制：ECM的致密化导致SMC的空间重组。这在渗透率和体积应变的经验本构关系中进行了总结。这导致了有趣的生理观察，作为中层微观结构变化的结果，内膜和中层对管壁水力阻力的相对贡献取决于施加的压力；在该血管中，中层阻力在压力约93毫米汞以上时占主导地位。
The hydraulic resistances of the intima and media determine water flux and the advection of macromolecules into and across the arterial wall. Despite several experimental and computational studies, these transport processes and their dependence on transmural pressure remain incompletely understood. Here, we use a combination of experimental and computational methods to ascertain how the hydraulic permeability of the rat abdominal aorta depends on these two layers and how it is affected by structural rearrangement of the media under pressure. Ex vivo experiments determined the conductance of the whole wall, the thickness of the media and the geometry of medial smooth muscle cells (SMCs) and extracellular matrix (ECM). Numerical methods were used to compute water flux through the media. Intimal values were obtained by subtraction. A mechanism was identified that modulates pressure-induced changes in medial transport properties: compaction of the ECM leading to spatial reorganization of SMCs. This is summarized in an empirical constitutive law for permeability and volumetric strain. It led to the physiologically interesting observation that, as a consequence of the changes in medial microstructure, the relative contributions of the intima and media to the hydraulic resistance of the wall depend on the applied pressure; medial resistance dominated at pressures above approximately 93 mmHg in this vessel.