Flow-dependent concentration polarization of plasma proteins at the luminal surface of a semipermeable membrane.
The effect of steady shear flow on concentration polarization of plasma proteins and lipoproteins at the luminal surface of a semipermeable vessel wall was studied experimentally using suspensions of these molecules in a cell culture medium and a semipermeable membrane dialysis tube which served as a model of an implanted vascular graft or an artery. The study was carried out by flowing a cell culture medium containing fetal calf serum or bovine plasma lipoproteins or bovine albumin through a 7.5 mm diameter, 60 mm-long dialysis tube in steady flow under a physiologic mean arterial perfusion pressure of 100 mmHg, and measuring the filtration velocity of water (cell culture medium) at the vessel wall which varied as a consequence of the change in concentration of plasma protein particles at the luminal surface of the semipermeable membrane dialysis tube. It was found that for perfusates containing plasma proteins and/or lipoproteins, filtration velocity of water was the lowest in the absence of flow, and it increased or decreased as the flow rate (hence wall shear rate) increased or decreased from a certain non-zero value, indicating that surface concentration of protein particles varied reversibly as a direct function of flow rate. It was also found that at particle concentrations equivalent to those found in a culture medium containing serum at 5% by volume, plasma lipoproteins which were much smaller in number and lower in concentration but larger in size than albumin, had a much larger effect on the filtration velocity of water than albumin. These findings were very much the same as those previously obtained with a cultured endothelial cell monolayer, strongly suggesting that the flow-dependent variation in filtration velocity of water at a vessel wall results from a physical phenomenon, that is, flow-dependent concentration polarization of low density lipoproteins at the luminal surface of the endothelial cell monolayer.
Naiki
T
T
Research Institute for Electronic Science, Hokkaido University, Sapporo, Japan. naiki@bfd.es.hokudai.ac.jp
Karino
T
T
D001158:Arteries; D001161:Arteriosclerosis / Q000209:etiology*; D001783:Blood Flow Velocity; D001798:Blood Proteins; D004730:Endothelium, Vascular; D005374:Filtration; D018056:Hemorheology; D006801:Humans; D008077:Lipoproteins, LDL; D008955:Models, Cardiovascular; D010316:Particle Size; D010477:Perfusion
D001798:Blood Proteins; D008077:Lipoproteins, LDL