Injury to human cells in culture induced by low density lipoprotein: An effect independent of receptor binding and endocytotic uptake of low density lipoprotein

Abstract

Cultured human endothelial cells isolated from umbilical cord veins and erythrocytes obtained from healthy donors were injured when exposed to low density lipoprotein (LDL). A close relationship between the amount of ¹²⁵I-LDL associated with the cell surface and the degree of cell injury was demonstrated. This association occurred before any morphological signs of cell injury were observed and before any substantial release of ⁵¹Cr into the medium could be measured. Subsequent endocytotic uptake and lysosomal degradation of LDL did not seem to be a prerequisite for the LDL-induced cell injury to occur. Human serum albumin had an inhibitory effect on the association of ¹²⁵I-LDL with the cell surface and in parallel a lowering effect on the ⁶¹Cr release.

Key-words:

• atherosclerosis
• endothelial cells
• erythrocytes
• lipoproteins
• LDL