Incretin-based investigational therapies for the treatment of MASLD/MASH.

Metabolic dysfunction-associated steatotic liver disease (MASLD), formerly known as non-alcoholic fatty liver disease (NAFLD), is the most common form of chronic liver disease. It exists as either simple steatosis or its more progressive form, metabolic dysfunction-associated steatohepatitis (MASH), formerly, non-alcoholic steatohepatitis (NASH). The global prevalence of MASLD is estimated to be 32% among adults and is projected to continue to rise with increasing rates of obesity, type 2 diabetes, and metabolic syndrome. While simple steatosis is often considered benign and reversible, MASH is progressive, potentially leading to the development of cirrhosis, liver failure, and hepatocellular carcinoma. Treatment of MASH is therefore directed at slowing, stopping, or reversing the progression of disease. Evidence points to improved liver histology with therapies that result in sustained body weight reduction. Incretin-based molecules, such as glucagon-like peptide-1 receptor agonists (GLP-1 RAs), alone or in combination with glucose-dependent insulinotropic polypeptide (GIP) and/or glucagon receptor agonists, have shown benefit here, and several are under investigation for MASLD/MASH treatment. In this review, we discuss current published data on GLP-1, GIP/GLP-1, GLP-1/glucagon, and GLP-1/GIP/glucagon RAs in MASLD/MASH, focusing on their efficacy on liver histology, liver fat, and MASH biomarkers.

Brouwers B ，Rao G ，Tang Y ，Rodríguez Á ，Glass LC ，Hartman ML ... -  《-》

Glucagon-like Peptide 1, Glucose-Dependent Insulinotropic Polypeptide, and Glucagon Receptor Agonists in Metabolic Dysfunction-Associated Steatotic Liver Disease: Novel Medication in New Liver Disease Nomenclature.

Chrysavgis LG ，Kazanas S ，Bafa K ，Rozani S ，Koloutsou ME ，Cholongitas E ... -  《INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES》

Glucagon-like peptide 1 agonists are potentially useful drugs for treating metabolic dysfunction-associated steatotic liver disease.

In this editorial, we comment on Yin et al's recently published Letter to the editor. In particular, we focus on the potential use of glucagon-like peptide 1 receptor agonists (GLP-1RAs) alone, but even more so in combination therapy, as one of the most promising therapies in metabolic dysfunction-associated steatotic liver disease (MASLD), the new definition of an old condition, non-alcoholic fatty liver disease, which aims to better define the spectrum of steatotic pathology. It is well known that GLP-1RAs, having shown outstanding performance in fat loss, weight loss, and improvement of insulin resistance, could play a role in protecting the liver from progressive damage. Several clinical trials have shown that, among GLP-1RAs, semaglutide is a safe, well-studied therapeutic choice for MASLD patients; however, most studies demonstrate that, while semaglutide can reduce steatosis, including steatohepatitis histological signs (in terms of inflammatory cell infiltration and hepatocyte ballooning), it does not improve fibrosis. Combinations of therapies with different but complementary mechanisms of action are considered the best way to improve efficiency and slow disease progression due to the complex pathophysiology of the disease. In particular, GLP-1RAs associated with antifibrotic drug therapy, dual glucose-dependent insulinotropic polypeptide (GIP)/GLP-1RA or GLP-1 and glucagon RAs have promoted greater improvement in hepatic steatosis, liver biochemistry, and non-invasive fibrosis tests than monotherapy. Therefore, although to date there are no definitive indications from international drug agencies, there is the hope that soon the therapeutic lines in the most advanced phase of study will be able to provide a therapy for MASLD, one that will certainly include the use of GLP-1RAs as combination therapy.

Soresi M ，Giannitrapani L 《-》

The role of incretin hormones and glucagon in patients with liver disease.

Non-alcoholic fatty liver disease (NAFLD) is defined as hepatic steatosis exceeding 5% of hepatocytes with no other reason for hepatic fat accumulation. The association between NAFLD and type 2 diabetes is strong. Accordingly, up to 70% of obese patients with type 2 diabetes have NAFLD. The spectrum of NAFLD ranges from simple steatosis to non-alcoholic steatohepatitis with variable degrees of fibrosis and cirrhosis. Cirrhosis is the end-stage of chronic liver disease and is characterised by diffuse fibrosis and nodular regeneration of hepatocytes. Alcoholic liver disease and NAFLD are the most common aetiologies of cirrhosis. The WHO estimates that 70% of patients with cirrhosis have impaired glucose tolerance and 30% have manifest diabetes. The latter is termed hepatic diabetes and is associated with increased complications to cirrhosis and hepatocellular carcinoma. The objective of this thesis was to study the impact of liver dysfunction on incretin and glucagon (patho)physiology in relation to glucose metabolism. We hypothesised that NAFLD patients with normal glucose tolerance would develop reduced incretin effect and that NAFLD would worsen the incretin effect in patients with existing type 2 diabetes. Thus, in study I, we investigated the incretin effect and glucagon secretion in patients with NAFLD with and without type 2 diabetes compared to controls. We also hypothesised that the incretin effect would be disturbed in non-diabetic patients with more severe liver disease. Hence, the objective of study II was to investigate the incretin effect in patients with cirrhosis. Finally, the hypothesis in study III was that an impaired glucagonostatic effect of GLP-1 contributes to the hyperglucagonaemia of patients with liver disease. We therefore explored the glucagonostatic properties of GLP-1 in non-diabetic patients with NAFLD. The results of study I show that patients with NAFLD have normal secretion of GLP-1 and GIP and a reduced incretin effect. The groups with type 2 diabetes have the lowest incretion effect. We also find that NAFLD patients have high fasting glucagon concentrations regardless of their glucose (in)tolerance. We further demonstrated that patients with normal glucose tolerance and NAFLD have preserved glucagon suppression to both oral and intravenous glucose.  In study II, we find that non-diabetic patients with cirrhosis have elevated concentrations of GLP-1 and GIP and a reduced incretin effect. Patients with cirrhosis also have fasting hyperglucagonaemia, but show intact glucagon suppression during both oral and intravenous glucose administration. Finally, study III demonstrates that normal glucose tolerant NAFLD patients had preserved glucagonostatic effect of GLP-1. In conclusion, our studies offer important information regarding the pathophysiology of glucose intolerance in patients with liver disease. We demonstrate that patients with NAFLD, in spite of normal glucose tolerance, have reduced incretin effect that is further aggravated by type 2 diabetes. We also find fasting hyperglucagonaemia in NAFLD patients, independently of type 2 diabetes. We show that cirrhosis is associated with impaired handling of oral glucose and reduced incretin effect. Finally, we find a preserved glucagonostatic effect of GLP-1 in patients with NAFLD, in spite of their hyperglucagonaemia. In light of our findings, the insulinotropic and glucagonostatic effects of GLP-1 receptor agonists might prove beneficial in patients with liver disease.

Junker AE 《Danish Medical Journal》

Glucagon-Like Peptide-1 Receptor Agonists and Dual Glucose-Dependent Insulinotropic Polypeptide/Glucagon-Like Peptide-1 Receptor Agonists in the Treatment of Obesity/Metabolic Syndrome, Prediabetes/Diabetes and Non-Alcoholic Fatty Liver Disease-Current Ev

Muzurović EM ，Volčanšek Š ，Tomšić KZ ，Janež A ，Mikhailidis DP ，Rizzo M ，Mantzoros CS ... -  《-》