Schematic overview of the major pathways involved in RCT from peripheral tissue and macrophages/foam cells. apoA-I is secreted by liver and intestine and loaded with cholesterol (CH) and phospholipids (PL) by ABCA1. The thus formed pre-β-HDL picks up cholesterol and phospholipid from ABCA1 in macrophages and peripheral cells and is converted to HDL2. HDL2 can be further loaded with cholesterol by ABCG1, and possibly SR-BI, in macrophages and delivers in turn its cargo to SR-BI in the liver. Zhang et al. (