Efflux of cholesterol from cholesterol loaded macrophages by incubation with synthetic HDL-particles

Westman J, Roobol C, Heymans C, Carlson LA, Wulfert E. Efflux of cholesterol from cholesterol loaded macrophages by incubation with synthetic HDL-particles. Scand J Clin Lab Invest 1993; 53: 773-782.Cells from the mouse monocyte/macrophage cell line J774A.1 were incubated with acetylated human low density lipoprotein for 2 days, resulting in an intracellular accumulation of mainly cholesteryl esters. These in vitro foam cell models were used to study the capability of synthetic HDL-particles to promote efflux of cholesterol. The synthetic HDL-particles were prepared from recombinant human proapolipoprotein A-I or human apolipoprotein A-I and phosphatidylcholine. Both types of reconstituted complexes were found to have a discoidal structure. A 24 h incubation of lipid loaded J774A.1 cells with these two types of discoidal complexes resulted in an equivalent and marked egress of cholesterol. The effect was the same whether the origin of phosphatidylcholine was egg yolk or soybean.