MC4R and metabolic dysfunction-associated steatohepatitis: LPS-treated melanocortin-4 receptor-deficient (Mc4r-KO) mice (MC4R regulates food intake and body weight) maintained on a Western diet results in a NASH disease model that progresses rapidly and results in fibrosis within 16 weeks [147], representing a major advantage over most other rodent NASH models used in these types of studies, in which steatosis and inflammation are robust but there is often little or no fibrosis.