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Aging promotes the development of diet‐induced murine steatohepatitis but not steatosis
Author(s) -
Fontana Luis,
Zhao Enpeng,
Amir Muhammad,
Dong Hanqing,
Tanaka Kathryn,
Czaja Mark J.
Publication year - 2013
Publication title -
hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.488
H-Index - 361
eISSN - 1527-3350
pISSN - 0270-9139
DOI - 10.1002/hep.26099
Subject(s) - steatosis , medicine , endocrinology , nonalcoholic fatty liver disease , steatohepatitis , fatty liver , liver injury , adipose tissue , inflammation , macrophage polarization , biology , macrophage , disease , biochemistry , in vitro
The prevalence of the metabolic syndrome and nonalcoholic fatty liver disease (NAFLD) in humans increases with age. It is unknown whether this association is secondary to the increased incidence of risk factors for NAFLD that occurs with aging, reflects the culmination of years of exposure to lifestyle factors such as a high‐fat diet (HFD), or results from physiological changes that characterize aging. To examine this question, the development of NAFLD in response to a fixed period of HFD feeding was examined in mice of different ages. Mice aged 2, 8, and 18 months were fed 16 weeks of a low‐fat diet or HFD. Increased body mass and insulin insensitivity occurred in response to HFD feeding irrespective of the age of the mice. The amount of HFD‐induced hepatic steatosis as determined biochemically and histologically was also equivalent among the three ages. Liver injury occurred exclusively in the two older ages as reflected by increased serum alanine aminotransferase levels, positive terminal deoxynucleotide transferase–mediated deoxyuridine triphosphate nick end‐labeling, and caspase activation. Older mice also had an elevated innate immune response with a more pronounced polarization of liver and adipose tissue macrophages into an M1 phenotype. Studies of cultured hepatocytes from young and old mice revealed that aged cells were selectively sensitized to the Fas death pathway. Conclusion : Aging does not promote the development of hepatic steatosis but leads to increased hepatocellular injury and inflammation that may be due in part to sensitization to the Fas death pathway and increased M1 macrophage polarization. (H EPATOLOGY 2013)