LDLR and obesity due to melanocortin 4 receptor deficiency: On the other hand, both LDL receptor-deficient (LDLR-/-) and particularly apolipoprotein E-deficient (ApoE-/-) mice display marked atherosclerosis [28,29] but ApoE-/- mice develop lower diet-induced obesity, less profound insulin resistance and adipose tissue inflammation when fed a high-fat diet [30-32].