Microviscometry reveals reduced blood viscosity and altered shear rate and shear stress profiles in microvessels after hemodilution
Microviscometry reveals reduced blood viscosity and altered shear rate and shear stress profiles in microvessels after hemodilution
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DOI：
10.1073/pnas.0402937101
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发表时间：
2004-07-06
影响因子：
11.1
通讯作者：
Damiano, ER
中科院分区：
文献类型：
--
作者：
Long, DS;Smith, ML;Damiano, ER
我们发现，许多显着的血液动力学流动特性，这是很难或不可能在体内的微血管评估，可以估计通过使用微粘度计和荧光微粒图像测速在直径>20微米的微血管。血液粘度，剪切应力和剪切速率的径向分布，并用于预测轴向压力梯度，表观粘度，和内皮细胞表面层厚度在体内。仅基于微粒图像测速数据，这是很容易获得的过程中，最活体显微镜协议从全身注射粒子示踪剂，我们表明，微粘度法一致预测减少局部和表观血液粘度等容血液稀释后。在其临床应用中，血液稀释是用于治疗需要降低外周血管流动阻力的各种病理的程序。我们的研究结果与此直接相关，因为它们表明全身红细胞压积的分数下降比伴随的体内微血管流动阻力的分数下降大约大25 -35%。就其基本用途而言，微粘度法提供了微血管血流动力学的全面定量分析，其在医学和生理学的广泛领域中具有应用，并且特别与血管生成、肿瘤生长、白细胞粘附、血管流动阻力、组织灌注和内皮细胞机械转导的定量研究相关。
We show that many salient hemodynamic flow properties, which have been difficult or impossible to assess in microvessels in vivo, can be estimated by using microviscometry and fluorescent microparticle image velocimetry in microvessels >20 mum in diameter. Radial distributions in blood viscosity, shear stress, and shear rate are obtained and used to predict axial pressure gradient, apparent viscosity, and endothelial-cell surface-layer thickness in vivo. Based solely on microparticle image velocimetry data, which are readily obtainable during the course of most intravital microscopy protocols from systemically injected particle tracers, we show that the microviscometric method consistently predicted a reduction in local and apparent blood viscosity after isovolemic hemodilution. Among its clinical applications, hemodilution is a procedure that is used to treat various pathologies that require reduction in peripheral vascular-flow resistance. Our results are directly relevant in this context because they suggest that the fractional decrease in systemic hematocrit is approximate to25-35% greater than the accompanying fractional decrease in microvascular-flow resistance in vivo. In terms of its fundamental usefulness, the microviscometric method provides a comprehensive quantitative analysis of microvascular hemodynamics that has applications in broad areas of medicine and physiology and is particularly relevant to quantitative studies of angiogenesis, tumor growth, leukocyte adhesion, vascular-flow resistance, tissue perfusion, and endothelial-cell mechanotransduction.