Erythrocyte flow and elasticity of microvessels evaluated by marginal cell-free layer and flow resistance
Erythrocyte flow and elasticity of microvessels evaluated by marginal cell-free layer and flow resistance
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DOI：
10.1152/ajpheart.1996.271.6.h2454
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发表时间：
1996-12-01
影响因子：
4.8
通讯作者：
Tateishi, N
中科院分区：
文献类型：
--
作者：
Maeda, N;Suzuki, Y;Tateishi, N
比较了内径为10-40 μ m的弹性(E)和硬化(H)微血管中红细胞的流动动力学，采用兔肠系膜分离血管床（E血管床）和4%多聚甲醛固定血管床（H血管床）测量了边缘无细胞层厚度和总体流动阻力。1)在E和H微血管中，无细胞层厚度随微血管内径的增大而增大，随红细胞压积的减小而减小，血流阻力整体减小。E微血管中无细胞层厚度的红细胞压积依赖性变化大于H微血管。H维管层的流动阻力始终大于E维管层。2) 2 mM二氮二羧酸二（N，N-二甲酰胺）处理后，红细胞变形能力降低，E微血管红细胞压积低时无细胞层厚度减小，H微血管红细胞压积高时无细胞层厚度减小，但两个血管床的流动阻力均增加。3)平均分子量为70,400的葡聚糖通过诱导红细胞聚集加速无细胞层的形成。当E微血管中葡聚糖含量为2-4 g/dl和H微血管中葡聚糖含量为1-2 g/dl时，无细胞层厚度急剧增加，同时流动阻力的增加明显降低。该研究得出结论，微血管的弹性可能在降低血管床的整体流动阻力方面发挥重要作用，血管床的流动阻力由边缘无细胞层调节，其本身是红细胞流变特性的功能。
Flow dynamics of human erythrocytes was compared in elastic (E) and hardened (H) microvessels with inner diameters of 10-40 mu m. The thickness of the marginal cell-free layer and the overall flow resistance were measured with a vascular bed isolated from rabbit mesentery (E vascular bed) as well as with a 4% paraformaldehyde-fixed bed (H vascular bed). 1) In both E and H microvessels, the thickness of the cell-free layer increased with increasing inner diameter of the microvessels and with decreasing hematocrit accompanied by an overall decrease in the flow resistance. The hematocrit-dependent change of the cell-free layer thickness was greater in the E microvessels than in the H microvessels. The flow resistance was always greater in the H vascular beds than in the E vascular beds. 2) With decreasing erythrocyte deformability induced by treatment with 2 mM diazenedicarboxylic acid bis(N,N-dimethylamide), the thickness of the cell-free layer decreased at a low hematocrit in the E microvessels at a high hematocrit in the H microvessels, although the flow resistance increased in both vascular beds. 3) Dextran of 70,400 average molecular weight accelerated the formation of the cell-free layer by inducing erythrocyte aggregation. A drastic increase in the cell-free layer thickness at 2-4 g/dl of dextran in the E microvessels and at 1-2 g/dl of dextran in the H microvessels was accompanied by a significantly lower increase in the flow resistance. This study concludes that the elasticity of microvessels may play an important role for reducing the overall flow resistance of a vascular bed, which is modulated by the marginal cell-free layer, itself a function of the rheological properties of the erythrocytes.