Studies from our group and others have revealed that angiopoietin-1, pregnancy-associated plasma protein-A, and homocysteine inhibit ABCA1- and ABCG1-dependent cholesterol efflux from lipid-loaded macrophages and aggravate atherosclerosis in apoE−/− mice by downregulating LXRα expression50–52. Here, PAPPA is linked to atherosclerosis.