Greene A S, Tonellato P J, Lui J, Lombard J H, Cowley A W
Department of Physiology, Medical College of Wisconsin, Milwaukee 53226.
Am J Physiol. 1989 Jan;256(1 Pt 2):H126-31. doi: 10.1152/ajpheart.1989.256.1.H126.
The purpose of this study was to quantitatively estimate the relative contribution of arteriolar rarefaction (disappearance of microvessels) and arteriolar constriction to the increases in total peripheral resistance and changes in the patterns of flow distribution observed in hypertension. A mathematical model of the hamster cheek pouch intraluminal microcirculation was constructed based on data from the literature and observations from our own laboratory. Separate rarefaction and constriction of third-order (3A) and fourth-order (4A) arterioles were performed on the model, and the results were quantified based on the changes of the computed vascular resistance. The degree of increase in resistance depended both on the number and the order of vessels rarefied or constricted and also on the position of those vessels in the network. The maximum increases in resistance obtained in the model runs were 21% for rarefaction and 75% for constriction. Rarefaction, but not constriction, produced large increases in the degree of heterogeneity of blood flow in the various vessel orders. These results demonstrate that vessel rarefaction significantly influences tissue blood flow resistance to a degree comparable with vessel constriction; however, unlike constriction, microvascular rarefaction markedly altered blood flow distribution in our model of the hamster cheek pouch vascular bed. These findings conform with the hypothesis that a significant component of the increase in total peripheral resistance in hypertension may be due to vessel rarefaction.
本研究的目的是定量评估小动脉稀疏（微血管消失）和小动脉收缩对高血压患者总外周阻力增加以及血流分布模式变化的相对贡献。基于文献数据和我们自己实验室的观察结果，构建了仓鼠颊囊腔内微循环的数学模型。在模型上分别对三级（3A）和四级（4A）小动脉进行稀疏和收缩操作，并根据计算出的血管阻力变化对结果进行量化。阻力增加的程度既取决于稀疏或收缩的血管数量和级别，也取决于这些血管在网络中的位置。模型运行中获得的最大阻力增加分别为稀疏时的21%和收缩时的75%。稀疏而非收缩导致各级血管中血流异质性程度大幅增加。这些结果表明，血管稀疏对组织血流阻力的影响程度与血管收缩相当；然而，与收缩不同，在我们的仓鼠颊囊血管床模型中，微血管稀疏显著改变了血流分布。这些发现符合以下假设：高血压患者总外周阻力增加的一个重要组成部分可能是由于血管稀疏。
