To further investigate the role of ROS in atherogenesis, we used atherosclerosis-prone hypercholesterolemic ApoE−/− mice, and performed treatment with the antioxidant vitamin E. The treatment effect of vitamin E was compared with that of the ACE inhibitor captopril because angiotensin II is an important contributor to ROS in the vasculature and cardiovascular system (Garrido and Griendling, 2009). Here, ACE is linked to atherosclerosis.