Phosphatidylserine-containing liposomes: Therapeutic potentials against hypercholesterolemia and atherosclerosis

Liposomes have been suggested as potential tools for cholesterol deposit mobilization from atherosclerotic lesions. Here, we explored the anti-atherosclerotic effects of phosphatidylserine (PS)-containing liposomes in vivo. High-fat diet-fed New Zealand white rabbits which were divided into groups receiving weekly intravenous injections of PS liposomes, atorvastatin-loaded PS (PSA) liposomes (100 μg phospholipid/kg), or control buffer for four weeks. The size and severity grade of atherosclerotic plaques as well as lipid profile were evaluated at the completion of study. In vitro, the expression and levels of anti/pro-inflammatory genes and proteins, respectively, and macrophage cholesterol efflux capacity (CEC) of nanoliposomes were evaluated. Both PS and PSA lowered serum LDL-C (P = 0.0034, P = 0.0041) and TC (P = 0.029, P = 0.0054) levels but did not alter TG and HDL-C levels. Plaque size and grade were reduced by PS (P = 0.0025, P = 0.0031) and PSA (P = 0.016, P = 0.027) versus control. Moreover, intima-media thickness was significantly reduced in the PS vs. control group (P = 0.01). In cultured cells, ICAM-1 expression in the PS (P = 0.022) and VCAM-1 expression in the PS and PSA groups (P = 0.037, P = 0.004) were suppressed while TGF-β expression was induced by both PS and PSA (P = 0.048, P = 0.046). Moreover, CEC from macrophages to nanoliposomes was enhanced by PSA (P = 0.003). Administration of anionic PS-containing liposomes could improve lipid profile and promote plaque regression through mechanisms that may involve cholesterol efflux and modulation of adhesion molecules.