MASH is estimated to affect millions of people globally and is often associated with metabolic disorders such as obesity and diabetes. Once MASH progresses to cirrhosis, patients face increased risk for life-threatening complications, including liver failure and hepatocellular carcinoma.

Researchers at University Hospital Münster (Germany), University Hospital Frankfurt am Main – Goethe University (Germany), Centre de Recherche sur L’inflammation, Université Paris-Cité, Inserm (France), Hôpital Beaujon AP-HP (France), Hospital Clínic de Barcelona-Institut de Recerca Biomèdica August Pi i Sunyer (IDIBAPS) (Spain), and EF CLIF (Spain) have developed a novel and accelerated animal model of advanced MASH-cirrhosis, offering new possibilities for testing and developing therapies targeting MASH which progression to cirrhosis represents a significant unmet medical need. This model aims to provide researchers with a more precise and efficient way to study advanced MASH-cirrhosis, characterized by both liver fibrosis and portal hypertension.

“MASLD and MASH are anticipated to become global pandemics, leading to significant morbidity and high mortality rates, particularly in cases of decompensated cirrhosis and acute-on-chronic liver failure (ACLF). Developing a faster and more advanced animal model for MASH-cirrhosis is essential to drive drug development and accelerate research in this field”, said Jonel Trebicka, senior author in the paper, Principal Investigator at University Hospital Münster and Senior Research Affiliate at EF CLIF.

The authors demonstrated that combining carbon tetrachloride (CCl4), a high-fat diet, and phenobarbital effectively accelerates the progression of MASH-cirrhosis in rats. “The acceleration of MASH-cirrhosis by phenobarbital leads to severe clinically significant portal hypertension, that is reflected by earlier decompensation and higher amounts of ascites at the time of decompensation compared to CCl4 and CCl4 plus Western diet alone. This underlines the strong hepatotoxic effects of phenobarbital, which is known to induce isozyme activities of cytochrome P450”, explained said Nico Kraus, predoctoral researcher at University Hospital Frankfurt am Main – Goethe University (Germany), and co-first author in the paper.

This accelerated timeline means that researchers can assess disease mechanisms and potential drug targets more efficiently. The use of phenobarbital, a cytochrome P450 inducer, proved instrumental in replicating the high metabolic stress characteristic of MASH in humans. Both short- and long-term phenobarbital regimens showed promise for experimental use, but the long-term model may be best suited for drug testing due to lower mortality rates and reduced acute toxicity in rats. Indeeed, the low-dose, long-term phenobarbital treatment proved especially effective in replicating human-like disease progression, presenting critical markers like steatosis and bridging fibrosis. “Notably, we observed advanced liver damage, including portal hypertension and characteristic histological features such as hepatic ballooning and inflammation”, said Frank E. Uschner, phisician at University Hospital Münster and co-first auhor in the paper.

“In our study, the high-dose, short-term model demonstrated greater severity, with the rapid dose escalation leading to a pronounced hepatotoxic phenotype. This short-term model may be particularly suited for investigating mechanisms of drug-induced liver injury in pre-existing chronic liver disease, while also being adaptable for inducing MASH-cirrhosis within 8 weeks. In contrast, the low-dose, long-term phenobarbital model displayed all key features of MASH-cirrhosis, with a rapid onset of severe portal hypertension within just 6 weeks, albeit with fewer acute toxic effects”, added Kraus.

“The low-dose long-term phenobarbital model is particularly suited for testing new therapeutics within a shorter timeframe, while avoiding the strong hepatotoxic effects observed in the high-dose short-term model”, said Sabine Klein, author in the paper and postdoctoral researcher at University Hospital Münster. One limitation of the study is the high mortality rate observed in the high-dose short-term model. “Although the addition of phenobarbital significantly reduced the time to develop cirrhosis and ascites, the high-dose short-term group showed a rather high mortality rate. Additionally, our MASH-cirrhosis models combine two etiological factors—drug-induced and metabolic liver damage—resulting in steatotic liver cirrhosis, but not MASH by strict definition”, added Klein.

This model provides a valuable platform for future research, as it could be used to evaluate potential therapies. “Our animal model of MASH-cirrhosis could be used to test new therapeutic targets and drugs for liver cirrhosis and ACLF”, concluded Trebicka.

Other authors in the study are Magnus Moeslein, Robert Schierwagen, Wenyi Gu, Maximilian Joseph Brol, Eike Fürst, Inga Grünewald, Sophie Lotersztajn, Pierre-Emmanuel Rautou, Marta Duran-Güell, Roger Flores Costa, and Joan Clària.