When SR-BI−/− and LDLr−/− apoA−/− mice fed on HFD received ROS inhibitor N-acetyl-l-cysteine (NAC), NAC reversed hypercholesterolemia-induced HSPC expansion, leukocytosis, and atherosclerosis progression in SR-BI−/− and LDLr−/− apoA-I−/− mice. Here, APOA1 is linked to familial hypercholesterolemia.