title: "Second hit" models of alcoholic liver disease.
abstract: Alcoholic liver disease (ALD) is a lifestyle disease with its pathogenesis and individual predisposition governed by gene-environment interactions. Based on the "second hit" or "multiple hits" hypothesis, patients are predisposed to progressive ALD when a magic combination of gene and environmental interactions exists. Reproduction of second or multiple hits in animal models serves to test a combination and to gain mechanistic insights into synergism achieved by such combination. Numerous environmental factors have been incorporated into animal models, largely classified into nutritional, xenobiotic/pharmacologic, hemodynamic, and viral groups. A loss or gain of function genetic model has become a popular experimental approach to test the role of a gene as a second hit. Future research will need to test more subtle or natural hits combined with excessive alcohol intake to test multiple hits in the genesis of ALD. Additionally, animal models of comorbidities are urgently needed particularly for synergistic liver disease and oncogenesis caused by alcohol, obesity, and hepatitis virus.
authors.affiliation: Southern California Research Center for ALPD and Cirrhosis, Keck School of Medicine of University of Southern California, Los Angeles, California 90033, USA. htsukamo@usc.edu
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Tsukamoto
authors.forename: Keigo
authors.initials: K
authors.lastname: Machida
authors.forename: Alla
authors.initials: A
authors.lastname: Dynnyk
authors.forename: Hasmik
authors.initials: H
authors.lastname: Mkrtchyan
mesh_terms: D000428:Alcohol Drinking / Q000009:adverse effects*; D000818:Animals; D015897:Comorbidity; D004195:Disease Models, Animal; D004777:Environment; D000431:Ethanol / Q000633:toxicity*; D020022:Genetic Predisposition to Disease; D006801:Humans; D008108:Liver Diseases, Alcoholic / Q000209:etiology* / Q000235:genetics; D012307:Risk Factors
chemical_list: D000431:Ethanol