APOE and atherosclerosis: However, irradiation that is required to deplete the hematopoietic compartment of recipient mice has been reported to have an intrinsic effect on the progression of atherosclerosis [16], and effects on atherosclerosis can differ between chimeric Ldlr-/- or apolipoprotein E knock out (Apoe-/-) mice when compared with findings obtained by using full knock outs.