APOE and atherosclerosis: A valuable contribution to this was made by the introduction of novel experimental methods such as gene targeting technology [13,14], which enabled the development of mouse models of atherosclerosis, namely the apolipoprotein E-knockout mouse model (Apoe-/-) [15,16,17] and the low-density lipoprotein (LDL) receptor-knockout mouse model (LDLR) [18].