APOE and hyperlipidemia: Mice lacking the Low Density Lipoprotein Receptor and fed a high-fat, high-cholesterol "Western" diet (LDLr-/-), as well as mice lacking apolipoprotein E fed a regular chow diet (ApoE-/-), develop hyperlipidemia and extensive aortic atherosclerosis, and are commonly used to model atherosclerosis in mice [22,23].