NAFLD exacerbates cholangitis and promotes cholangiocellular carcinoma in mice

Nonalcoholic fatty liver disease (NAFLD) is an increasingly common condition, affecting up to 25% of the population worldwide. NAFLD has been linked to several conditions, including hepatic inflammation, fibrosis, and hepatocellular carcinoma (HCC), however the role of NAFLD in cholangitis and the development of cholangiocellular carcinoma (CCC) remains poorly understood. This study investigated whether a high‐fat diet (HFD) promotes cholangitis and the development of CCC in mice. We used liver‐specific E‐cadherin gene (CDH1) knockout mice, CDH1(∆Liv), which develop spontaneous inflammation in the portal areas along with periductal onion skin‐like fibrosis, similar to that of primary sclerosing cholangitis (PSC). An HFD or normal diet (ND) was fed to CDH1(∆Liv) mice for 7 mo. In addition, CDH1(∆Liv) mice were crossed with LSL‐Kras(G12D) mice, fed an HFD, and assessed in terms of liver tumor development. The extent of cholangitis and number of bile ductules significantly increased in mice fed an HFD compared with ND‐administered CDH1(∆Liv) mice. The numbers of Sox9 and CD44‐positive stem cell‐like cells were significantly increased in HFD mice. LSL‐Kras(G12D) /CDH1(∆Liv) HFD mice exhibited increased aggressiveness along with the development of numerous HCC and CCC, whereas LSL‐Kras(G12D)/CDH1(∆Liv) ND mice showed several macroscopic tumors with both HCC and CCC components. In conclusion, NAFLD exacerbates cholangitis and promotes the development of both HCC and CCC in mice.