Adult mouse model of early hepatocellular carcinoma promoted by alcoholic liver disease.

AIM: To establish a mouse model of alcohol-driven hepatocellular carcinoma (HCC) that develops in livers with alcoholic liver disease (ALD).

METHODS: Adult C57BL/6 male mice received multiple doses of chemical carcinogen diethyl nitrosamine (DEN) followed by 7 wk of 4% Lieber-DeCarli diet. Serum alanine aminotransferase (ALT), alpha fetoprotein (AFP) and liver Cyp2e1 were assessed. Expression of F4/80, CD68 for macrophages and Ly6G, MPO, E-selectin for neutrophils was measured. Macrophage polarization was determined by IL-1β/iNOS (M1) and Arg-1/IL-10/CD163/CD206 (M2) expression. Liver steatosis and fibrosis were measured by oil-red-O and Sirius red staining respectively. HCC development was monitored by magnetic resonance imaging, confirmed by histology. Cellular proliferation was assessed by proliferating cell nuclear antigen (PCNA).

RESULTS: Alcohol-DEN mice showed higher ALTs than pair fed-DEN mice throughout the alcohol feeding without weight gain. Alcohol feeding resulted in increased ALT, liver steatosis and inflammation compared to pair-fed controls. Alcohol-DEN mice had reduced steatosis and increased fibrosis indicating advanced liver disease. Molecular characterization showed highest levels of both neutrophil and macrophage markers in alcohol-DEN livers. Importantly, M2 macrophages were predominantly higher in alcohol-DEN livers. Magnetic resonance imaging revealed increased numbers of intrahepatic cysts and liver histology confirmed the presence of early HCC in alcohol-DEN mice compared to all other groups. This correlated with increased serum alpha-fetoprotein, a marker of HCC, in alcohol-DEN mice. PCNA immunostaining revealed significantly increased hepatocyte proliferation in livers from alcohol-DEN compared to pair fed-DEN or alcohol-fed mice.

CONCLUSION: We describe a new 12-wk HCC model in adult mice that develops in livers with alcoholic hepatitis and defines ALD as co-factor in HCC.