Lever M J, Jay M T
Physiological Flow Studies Unit, Imperial College of Science, Technology and Medicine, London, UK.
Front Med Biol Eng. 1993;5(1):45-50.
The early stages of atherosclerosis involve the accumulation of plasma constituents, including fibrinogen, lipoproteins and lipids and their modified forms. To assess the role of haemodynamics in these processes, we have measured the pressure dependence of the fluxes of albumin, fibrinogen and fluid through the whole thickness of the walls of the carotid artery and the inferior vena cava. Fluxes were much higher across the vein, the vessel which is less susceptible to atherosclerosis. Protein fluxes showed a marked non-linear dependence on transmural pressure which was greater than the pressure dependence of the fluid fluxes. Protein movement across the artery wall could be modelled assuming a significant convective component with the protein reflection coefficient decreasing as the wall tissue was stretched by the increasing pressure. Protein movement across the vein wall appeared to be dependent on ultrafiltration with the formation of a concentration polarization layer at the luminal interface; such a layer would be extremely sensitive to flow within the vessel lumen.
动脉粥样硬化的早期阶段涉及血浆成分的积累，包括纤维蛋白原、脂蛋白、脂质及其修饰形式。为了评估血流动力学在这些过程中的作用，我们测量了白蛋白、纤维蛋白原和液体通过颈动脉和下腔静脉整个管壁厚度时通量的压力依赖性。静脉（即较不易患动脉粥样硬化的血管）的通量要高得多。蛋白质通量对跨壁压力呈现出显著的非线性依赖性，这种依赖性大于液体通量对压力的依赖性。假设存在显著的对流成分，随着压力增加导致管壁组织拉伸，蛋白质反射系数降低，可对蛋白质穿过动脉壁的运动进行建模。蛋白质穿过静脉壁的运动似乎依赖于超滤作用，在管腔界面形成浓度极化层；这样的层对血管腔内的血流极其敏感。
