Notably, it has been shown that mice overexpressing Olr1 on an ApoE KO background develop markedly more atherosclerosis than their nontransgenic littermates (26) and that Olr1 deficiency on an Ldlr KO background reduces the atherogenic burden conferred by 18 weeks of a 4% cholesterol/10% cocoa butter diet (27). This evidence concerns the gene APOE and atherosclerosis.