DYNAMICS OF FLOW-DEPENDENT ARTERIAL PERMEABILITY

描述（由申请方提供）：本研究的总体目标是了解体内血流动力学应激如何影响动脉壁对大分子的摄取以及伴随的血管炎症反应。对大分子转运和炎症的兴趣是由于它们在动脉粥样硬化的发生和发展中的重要性。本研究的一个主要假设是血管内皮功能受到血流动力学应激变化的严重影响。这是在两种情况下进行检查：适应性内皮细胞响应昼夜变化的局部剪切应力，和细胞的敏感性的谐波内容的剪切应力波形。假设适应性反应和长期暴露于具有高谐波含量的剪切波形与内皮屏障功能和炎症介质表达的降低相关。 研究计划包括两个系列的动物实验，并在层流室培养的内皮细胞的研究。在基线实验中，将使用伊文思蓝染料-白蛋白复合物的照相密度测定法测量猪冠状动脉（CA）和髂外动脉（EIA）中大分子渗透性的空间变化。CA中的渗透性分布将在逐部位基础上与同一血管中的壁剪切应力测量值相关;后者将从动脉注射模型得出的计算区域中的流动模拟中获得。在分流实验中，一个EIA中的流动和剪切应力将通过动静脉分流升高，而另一个动脉作为对照;将评估白蛋白摄取对增加的持续时间和幅度的依赖性。在两个系列中，将回收固定的组织和未固定的内皮细胞，并测量内皮单层组织、蛋白质分布和水平以及基因表达。在基线试验中，这些数据将与局部剪切和剪切波形相关，并将CA和EIA的响应进行比较。在分流实验中，它们将被用来确定伴随适应的分子过程。流动室实验将培养的猪动脉内皮细胞暴露于复制体内流动环境的选定组分的流动，以分离它们对体内反应的贡献。将检查高胆固醇血症对正常血脂动物中发现的显著反应的影响。

DESCRIPTION (provided by applicant): The overall objective of this research is to understand how hemodynamic stress in vivo affects the uptake of macromolecules by the arterial wall and the accompanying vascular inflammatory response. The interest in macromolecular transport and inflammation is prompted by their importance in the genesis and development of atherosclerosis. A primary hypothesis of this research is that vascular endothelial function is critically influenced by changes in hemodynamic stress. This is examined in two contexts: the adaptive endothelial response to diurnal variations in local shear stress, and the sensitivity of the cells to the harmonic content of the shear stress waveform. It is hypothesized that both the adaptive response and chronic exposure to shear waveforms with high harmonic content are associated with decreases in the barrier function of the endothelium and the expression of inflammatory mediators. The research plan includes two series of animal experiments, and studies of cultured endothelial cells in laminar flow chambers. In baseline experiments, the spatial variation of macromolecular permeability in the coronary (CA) and external iliac arteries (EIA) of swine will be measured using photographic densitometry of Evans Blue dye-albumin complex. The permeability distribution in the CA will be correlated on a site-by-site basis against measures of wall shear stress in the same vessel; the latter will be obtained from flow simulations in computational regions derived from injection casts of the arteries. In shunt experiments, the flow and shear stress in one EIA will be raised by arteriovenous shunting, while the other artery serves as a control; the dependence of albumin uptake on the duration and magnitude of the increase will be assessed. In both series, fixed tissue and unfixed endothelial cells will be recovered, and endothelial monolayer organization, protein distribution and levels, and gene expression will be measured. In the baseline experiments, these data will be related to local shear and shear waveform, and the responses of the CA and EIA will be compared. In the shunt experiments, they will be used to identify the molecular process accompanying adaptation. Flow chamber experiments will expose cultured porcine arterial endothelial cells to flows that replicate selected components of the in vivo flow environment, to isolate their contributions to the in vivo response. The influence of hypercholesterolemia on significant responses found in the normolipemic animals will be examined.