Genetically Engineered Pig Liver Sustains Human Life for 171 Days in Groundbreaking Xenotransplantation

In a significant medical breakthrough, researchers in China successfully implanted a genetically modified pig liver into a human patient, demonstrating the organ's ability to function for an extended period. This pioneering auxiliary xenotransplant, reported by sciencedaily on December 7, 2025, marks a crucial step in addressing the critical global shortage of donor organs.

The recipient, a 71-year-old man suffering from hepatitis B-related cirrhosis and hepatocellular carcinoma, was deemed ineligible for a conventional human liver transplant, according to a report in the Journal of Hepatology. The experiment provided vital proof-of-concept that modified porcine livers can perform essential metabolic and synthetic functions within a human body.

The pig liver used in the procedure featured 10 specific gene edits, designed to enhance compatibility and reduce the risk of rejection, ScienceDaily noted. These modifications aimed to overcome the significant immunological barriers typically encountered in cross-species organ transplantation.

While the patient ultimately passed away after 171 days, the extended functional period of the xenograft is a remarkable achievement. Researchers, as detailed in the Journal of Hepatology, attributed the patient's passing to complications including coagulation dysregulation and immune issues, highlighting persistent challenges in long-term xenotransplantation.

This experimental effort, conducted by a team led by Beicheng Sun, MD, PhD, at the First Affiliated Hospital, Anhui Medical University in Hefei, China, offers a potential new avenue to bridge the gap between organ demand and availability. Experts believe it could reshape the future of organ replacement for patients with acute liver failure and other severe conditions.

Heiner Wedemeyer, Co-Editor of the Journal of Hepatology, commented that this case signifies that "a new era of transplant hepatology has started". He emphasized that the findings showcase both the immense promise and the remaining biological and ethical hurdles that must be overcome for wider clinical application.

• Historical Context and Previous Milestones: Xenotransplantation, the transfer of organs between species, has a long history of research, with earlier attempts involving baboon hearts and pig kidneys into humans. The National Kidney Foundation reported that pigs became the preferred donor animal in the 1990s due to their organ size similarity to humans and availability. Prior to this liver success, a genetically modified pig liver was transplanted into a brain-dead patient in China in March 2025, functioning for 10 days, as reported by The Guardian.

• Addressing the Global Organ Shortage: The World Health Organization estimates that less than 10% of the global organ transplantation need is met, with thousands dying annually while awaiting donor organs. In the United States alone, over 100,000 people are on transplant waiting lists, according to Donate Life America. This successful pig liver transplant offers a glimmer of hope for alleviating this severe imbalance between organ supply and demand.

• Technical Advancements and Remaining Challenges: The pig liver used in the recent transplant featured 10 genetic modifications, including xenoantigen knockouts and human transgenes, to improve immune and coagulation compatibility, the Journal of Hepatology detailed. Despite these advancements, the patient experienced complications like coagulation dysregulation and immune responses, which Frontiers Publishing Partnerships notes are persistent lethal barriers in liver xenotransplantation, unlike heart and kidney transplants.

• Ethical and Societal Considerations: The use of genetically modified pigs for organ donation raises significant ethical questions, including animal welfare, the potential for zoonotic disease transmission, and the need for long-term monitoring of recipients, according to a review in GMO Biosafety Research. Organizations like the ERLC also highlight concerns about the moral implications of using animals as organ sources and the societal acceptance of such procedures.

• Potential Future Applications and Research Directions: Experts suggest that liver xenografts could initially serve as a "bridge" to allotransplantation, providing temporary support for patients with acute liver failure while awaiting a human donor, as discussed by Frontiers Publishing Partnerships. Dr. Elan Kumaran, a Liver Transplant Surgeon, noted in a December 2025 interview that while still experimental, such modalities are showing success in experimental settings. Continued research is focused on further genetic modifications and immunosuppressive therapies to overcome current limitations.

• Regulatory Landscape and Clinical Trials: The U.S. Food and Drug Administration (FDA) has already approved the first human clinical trials for kidney xenotransplantation to begin in 2025, after decades of research, as reported by the National Kidney Foundation. These trials will proceed cautiously, focusing on safety and efficacy, with institutions like Johns Hopkins Medicine receiving significant funding to advance preclinical studies toward human clinical trials for various organs.