Macrophage cholesterol removal by triglyceride-phospholipid emulsions

Phospholipid liposomes were previously shown to mobilize cholesterol from cultured macrophage foam cells. Because Intralipid, a clinically available triglyceride-phospholipid emulsion, contains both phospholipid liposomes and triglyceride-emulsion particles, we sought to study its effect on macrophage cholesterol mobilization. Following an 18h incubation of J774 macrophages in serum-free medium supplemented with Intralipid, cholesteryl ester content decreased by up to 50% in previously cholesterol-loaded cells, and by 25% in non-loaded cells. Both components of Intralipid, liposomes and emulsion particles, independently caused reductions in cellular cholesteryl ester. We conclude that clinically available triglyceride-phospholipid emulsions can mobilize macrophage cholesterol in vitro.