Reproducibility and Sex Differences in a STZ-High-Fat Diet Model of MASLD and Early Hepatocarcinogenesis.

Primary liver cancer, particularly hepatocellular carcinoma (HCC), remains a major global health burden, ranking as the fifth most common cancer and the third leading cause of cancer-related mortality worldwide. The rising incidence of HCC is closely linked to metabolic comorbidities, including non-alcoholic fatty liver disease (NAFLD), underscoring the need for improved diagnostic and therapeutic strategies. NAFLD can progress to metabolic dysfunction-associated steatohepatitis (MASH), characterized by inflammation and fibrosis, which markedly increases HCC risk, especially in individuals with obesity and type 2 diabetes (T2D). NAFLD has recently been redefined as metabolic dysfunction-associated steatotic liver disease (MASLD) to better reflect its metabolic basis. However, robust experimental models to study the progression from MASLD to MASH and ultimately HCC remain limited. This proof-of-concept study investigates sex-specific effects of metabolic dysregulation using the STAM (STelic Animal Model; streptozotocin and high-fat diet) mouse model, which recapitulates key features of human MASH and HCC. Neonatal C57BL/6J mice received streptozotocin to induce T2D-like symptoms followed by a high-fat diet. Streptozotocin (STZ) treated mice showed reduced body fat, lower insulin levels, impaired glucose tolerance, and increased expression of genes linked to inflammation, lipid metabolism, and apoptosis. These findings support the STAM model's utility for MASLD research and highlight the importance of sex-specific strategies to limit HCC progression.