LEP and obesity due to melanocortin 4 receptor deficiency: Most studies on the role of hepatic innate immunity in NAFLD has been generated by studying leptin-deficient (ob/ob) mice and leptin-resistant (fa/fa) rats, animals, which spontaneously develop fatty livers and naturally exhibit features, such as insulin resistance, obesity, and dyslipidemia, which in its turn in humans are strongly correlated with NAFLD [57-60].