Concomitant treatment of cholesterol-fed ApoE−/− mice with LT, the specific synthetic Rac1 inhibitor NSC 23766 or simvastatin comparably reduced aortic Rac1 activity, NADPH oxidase activity, oxidative stress, endothelial dysfunction, atherosclerosis development, and macrophage infiltration. This evidence concerns the gene FMO5 and endothelial dysfunction.