ABSTRACT
To test the hypothesis that concentration polarization of atherogenic lipids may occur in the arterial system and play an important role in localization of atherosclerosis, we simulated and measured in vitro the luminal surface concentration of low density lipoprotein (LDL) in local stenosis at the distal end of carotid artery by number simulation and laser scanning confocal microscopy, then we designed carotid stenosis model to test the role of LDL concentration polarization in atherogenesis. The in vitro experiment showed that the luminal surface LDL concentration was higher than the bulk concentration as predicted by the concentration polarization theory. The relative luminal surface LDL concentration changed with the flow velocity and ratio of stenosis. The wall concentration of LDL was highest in the round tube with 40% stenosis at the same velocity, while the wall concentration of LDL was higher when Re was 250 than Re was 500 at the same extent of narrowness. The animal experiment also revealed that general atherogenic plaques obviously occurred at the distal end of local stenosis where concentration polarized. The results strongly support our hypothesis that concentration polarization of lipoproteins occurs in local stenosis at the distal end of carotid artery, and this in turn promotes the localization of atherosclerosis which develops in the arterial system.