APOA1 and atherosclerosis: ATP-binding cassette transporter A1 (ABCA1) and G1 (ABCG1) mediate cholesterol efflux from foam cells to the extracellular cholesterol acceptors apolipoprotein A-I (ApoA-I) and high-density lipoprotein (HDL), respectively, thereby limiting foam cell formation and decreasing the progression of atherosclerosis [14,15].