EFFLUX OF CHOLESTEROL FROM CHOLESTEROL-LOADED MACROPHAGES BY INCUBATION WITH SYNTHETIC HDL-PARTICLES

Cells from the mouse monocyte/macrophage cell line J774A.1 were incuba ted with acetylated human low density lipoprotein for 2 days, resultin g in an intracellular accumulation of mainly cholesteryl esters. These in vitro foam cell models were used to study the capability of synthe tic HDL-particles to promote efflux of cholesterol. The synthetic HDL- particles were prepared from recombinant human proapolipoprotein A-I o r human apolipoprotein A-I and phosphatidylcholine. Both types of reco nstituted complexes were found to have a discoidal structure. A 24 h i ncubation of lipid loaded J774A.1 cells with these two types of discoi dal complexes resulted in an equivalent and marked egress of cholester ol. The effect was the same whether the origin of phosphatidylcholine was egg yolk or soybean.