Correa, Julio Cisneros

The persistent shortage of allogenic donor organs has driven the exploration of xenotransplantation as a viable alternative for patients with end-stage liver disease. This review investigates the progress and challenges in liver xenotransplantation, focusing on the use of genetically engineered animals, particularly pigs, as potential organ donors. This narrative review discusses various sources of xenografts, highlighting their advantages and limitations, and provides a historical overview of liver xenotransplantation, encompassing both clinical and experimental experiences. Key obstacles, such as immunological rejection, coagulation dysfunction, and the risk of zoonotic infections, are analyzed, with emphasis on how these challenges have been addressed through genetic modifications and adjunctive therapies. Recent clinical trials are also reviewed, offering insights into the outcomes and lessons learned from these pioneering efforts. We also explored the regulatory, legal, and ethical considerations critical to advancing liver xenotransplantation into clinical practice, along with future perspectives on the field’s evolution. This comprehensive overview aims to provide a clear understanding of the current state of liver xenotransplantation and the strategies being developed to overcome existing barriers, paving the way for future clinical applications.

Metabolic dysfunction-associated steatohepatitis (MASH) is a global health care burden. Appropriate large animal models mimicking the main MASH characteristics of steatosis, inflammation, and hepatocyte damage alongside progression of fibrosis are imperative for robust preclinical studies, especially in the field of hepatobiliary surgery. The present study aimed to characterize a novel model of steatohepatitis in fumarylacetoacetate hydroxylase-deficient ( FAH -/- ) pigs. FAH -/- pigs were generated using a CRISPR/Cas9 system. The animals received a choline-deficient, L-amino acid-defined high-fat diet and subtherapeutic doses of nitisinone and were followed for 3 months. Liver biopsies were obtained at baseline and every month during treatment. Steatosis, inflammation, and fibrosis were assessed by conventional histological scoring systems and by an artificial intelligence (AI) model. Serum liver parameters were analyzed every 2 weeks. Steatosis increased significantly throughout the study, with severe steatosis observed as early as 2 months into treatment. The inflammation score was increased in all animals after 3 months of treatment, whereas the AI-based CD45+ cell count showed region-specific trends in the portal and lobular areas. Collagen content and the corresponding fibrosis stage showed an increase over the 3-month period; however, the difference was not significant. Serum liver parameters did not show any relevant elevations during the study. In summary, we successfully developed and characterized a novel model of steatohepatitis in the FAH -/- pig within 3 months. Further studies with prolonged observation time and/or cycling of nitisinone administration are needed to evaluate whether progressive fibrosis and cirrhosis could be achieved with this model.