In Vitro Accumulation of Complexes of Endotoxin and Low-Density Lipoproteins by Macrophages and Arterial Wall

Abstract

Binding and uptake of complexes of endotoxin and low-density lipoproteins (LPS-LDL) in the arterial wall and mononuclear phagocytes were studied under in vitro conditions. Incubation of aortic explants from Wistar rats with complexes of (125)I-LDL and S. minnesota R595 LPS or (125)I-LDL was accompanied by a 6-fold increase in binding (0 degrees C) and 2-fold increase in the uptake (37 degrees C) of LDL-LPS complexes as compared to free LDL. Binding and degradation of (125)I-LDL-LPS complexes in the culture of peritoneal macrophages were higher compared to the corresponding parameters for free (125)I-LDL. Our results suggest that the formation of LDL-LPS complexes is followed by the increased binding and accumulation of LDL in the arterial wall and macrophages. These changes probably induce the cascade of major atherogenic events in the vascular wall.