STRUCTURE AND HEMODYNAMICS OF MICROVASCULAR NETWORKS - HETEROGENEITY AND CORRELATIONS
STRUCTURE AND HEMODYNAMICS OF MICROVASCULAR NETWORKS - HETEROGENEITY AND CORRELATIONS
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DOI：
10.1152/ajpheart.1995.269.5.h1713
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发表时间：
1995-11-01
影响因子：
4.8
通讯作者：
GAEHTGENS, P
中科院分区：
文献类型：
--
作者：
PRIES, AR;SECOMB, TW;GAEHTGENS, P
本研究的目的是量化微血管网络的拓扑，形态和血流动力学参数的异质性，并确定这些参数之间的功能相关性。检查了大鼠肠系膜中的7个网络（每个网络383-983个血管段），并测量了所有节段（n = 3，129）中的节段生成、直径、长度和血细胞比容以及流速（仅在3个网络中，1，321个节段）。此外，从数学模拟中推导出所有节段的红细胞压积、流速和压力。所有参数均表现出非均匀分布，变异系数范围从0.28（毛细管直径）到> 1.5（体积流量和压力梯度）。参数之间存在几种强相关性，例如，排出血细胞比容随血管直径增加而增加，剪切速率随血管内压力增加而增加。由于这种相关性，从“典型血管”的平均值到网络属性的外推可能导致大量错误。例如，基于平均数量估计的平均网络传输时间为6.5 s，比真实值（4.08 s）高出约60%。因此，血管床的简化模型可能不足以描述微循环的功能特性。
The objective of this study was to quantify the heterogeneity of topological, morphological, and hemodynamic parameters in microvascular networks and to identify functionally relevant correlations among these parameters. Seven networks in the rat mesentery (383-983 vessel segments per network) were examined, and measurements were made of segment generation, diameter, length, and hematocrit in all segments (n = 3,129) and of flow velocity (only in 3 networks, 1,321 segments). In addition, hematocrit, flow rate, and pressure were derived for all segments from a mathematical simulation. All parameters obtained exhibit heterogeneous distributions with coefficients of variation ranging from 0.28 (capillary diameter) to > 1.5 (volume flow and pressure gradient). Several strong correlations exist between parameters, e.g., discharge hematocrit increases with vessel diameter, and shear rate increases with intravascular pressure. Because of such correlations, the extrapolation from average values for ''typical vessels'' to network properties can lead to substantial errors. For example, the mean network transit time estimated based on averaged quantities is 6.5 s, which is about 60% higher than the true value (4.08 s). Simplified models of the vascular bed may therefore be inadequate to describe functional properties of the microcirculation.