Factors modulating the interaction of LDL with an arterial lipoprotein complexing proteoglycan: the effect of HDL.

The presence of a lipoprotein complexing proteoglycan (LCP) in extracts of human arterial intima/media that forms specific complexes with low density lipoproteins (LDL) has suggested that it may play a role in the interaction of LDL with the arterial wall and the atherogenic process. The formation of insoluble LDL-LCP complexes by incubation of serum with arterial extracts appears directly related to the concentration of LDL and inversely to the content of high density lipoproteins (HDL), indicating that HDL may inhibit the interaction between LDL and LCP. This inhibition is clearly visible by addition of HDL to LCP containing extracts before their incubation with LDL. This effect is also shown by apoHDL but not by lipoprotein-free plasma. It is suggested that the HDL/LDL ratio of the plasma crossing the endothelial barrier may be an important modulator of the net accumulation of LDL in the intima/media and of its contribution to atherogenesis.