APOA1 and atherosclerosis: RCT is the major route for removing excess cholesterol and oxysterols from macrophages to prevent foam-cell formation in the aortic wall and protect against atherosclerosis.[8,26,27] ATP-binding cassette transporter A1 (ABCA1; synthesized in liver and intestine) and ATP-binding cassette transporter G1 (ABCG1) efflux cholesterol and phospholipids to ApoAI to form nascent HDL [Figure 1].