A novel diet‐induced murine model of steatohepatitis with fibrosis for screening and evaluation of drug candidates for nonalcoholic steatohepatitis

Abstract

Many animal models of nonalcoholic steatohepatitis have been reported. While these models exhibit mild onset of hepatitis and fibrosis, induction is often slow. For faster screening of drug candidates, there is a compelling need for convenient animal models of steatohepatitis and nonalcoholic steatohepatitis in which fatty liver and hepatitis are stably induced within a short period. Here, we analyzed the hepatic lipid composition in nonalcoholic steatohepatitis, and used this information to successfully establish a murine model where steatohepatitis is induced within only 1 week using a novel diet (steatohepatitis‐inducing high‐fat diet, STHD‐01) high in saturated fatty acids and cholesterol. After receiving STHD‐01 for 1 week, normal mice (C57BL/6J) showed elevated markers of fatty liver and hepatitis, including hepatic triglycerides and plasma alanine aminotransferase; the administration of angiotensin receptor blockers reduced these symptoms. Furthermore, we confirmed that STHD‐01 administration for 36 weeks induced not only sustained elevation of hepatic triglyceride and plasma alanine aminotransferase levels, but also fibrosis and tumor formation. Pretreatment with the carcinogen diethylnitrosamine accelerated tumor formation, and hepatic lesions were observed within 30 weeks of STHD‐01 feeding following diethylnitrosamine pretreatment. Finally, branched‐chain amino acids, known to reduce the risk for hepatocellular carcinoma in preclinical models, were effective in reducing the progression of liver fibrosis induced by STHD‐01 feeding after diethylnitrosamine pretreatment. We concluded that STHD‐01 administration successfully induces steatohepatitis within a short period of time. The proposed murine model is suitable for studying the long‐term effects of pharmaceutical agents targeting steatohepatitis, fibrosis, and tumor formation.

Rodent Models of Nonalcoholic Fatty Liver Disease

“…At 36 weeks, perivenular-pericellular fibrosis and a slender, chicken-wire pattern were observed in the liver tissue of StHD-01-fed mice, as well as extensive fibro-DOI: 10.1159/000501851 sis of the entire liver and even benign tumors in some mice. Ejima et al [23] also found that STHD-01 augmented the tumorigenic potential of diethylnitrosamine. STHD-01 model is suitable for screening and evaluation of drug candidates for steatohepatitis, fibrosis, and tumor formation.…”

“…Recently, Ejima et al [23] developed novel dietary model of NASH named steatohepatitis-inducing HFD (STHD-01) with a 5% cholesterol and 40% fat content, which is rich in high saturated fatty acids and cholesterol. Hepatic steatosis and steatohepatitis induced by STHD-01 take a short period.…”

Nrf2-mediated anti-oxidant effects contribute to suppression of non-alcoholic steatohepatitis-associated hepatocellular carcinoma in murine model

“…Mice were fed the STHD-01 (11% kcal/protein, 72% kcal/fat, and 17% kcal/nitrogen-free extracts; EA Pharmaceuticals Co., Ltd., Tokyo, Japan) for 41 weeks. ( 21 ) The control group was fed a standard diet (SD) (AIN-93G; 19% kcal/protein, 12% kcal/fat, and 69% kcal/nitrogen-free extract). Mice were treated with a cocktail of antibiotics (Abx) (1 g/L ceftazidime and 1 g/L metronidazole; both from Sigma-Aldrich, St. Louis, MO) to deplete the gut microbiota.…”

“…This diet reportedly causes mice to develop NASH and NASH-associated HCC in 9 and 36 weeks, respectively. ( 21 ) We used a murine model of NASH-associated HCC without the use of carcinogens. The aim of this study was to determine whether Nrf2 and its related anti-oxidant effects prevented or aided the development of NASH-associated HCC in this murine model.…”

Gut microbiota-mediated generation of saturated fatty acids elicits inflammation in the liver in murine high-fat diet-induced steatohepatitis

“…A recent study has reported a new class of HFD, known as steatohepatitis-inducing HFD (STHD)-01. The consumption of STHD-01 promotes the development of NASH-like pathology within a short period of time [ 12 ]. However, since STHD-01 is a recently developed diet, it remains unclear whether this diet impacts the gut microbiota and its metabolic activities, promoting NASH development, similar to that of the commonly used HFD.…”