There is a shortage of donor organs. Pig organs could offer a solution. A team at the MHH is conducting research on this in a new project on xenotransplantation. When an organ stops functioning and other treatments are no longer effective, an organ transplant is necessary. It saves many lives every year. At the Hannover Medical School (MHH), Germany’s largest transplant center, 300 to 400 organs are transplanted each year—primarily kidneys, lungs, livers, and hearts. However, the demand for donor organs far exceeds the supply. In Germany, approximately 8,200 people are currently waiting for a donor organ, with about 1,000 of them in Hannover alone. „The shortage of suitable donor organs is one of our greatest clinical challenges,“ says Prof. Dr. Moritz Schmelzle, director of the MHH Transplant Center. „We see it as our most urgent task to advance innovations in transplant medicine that could address this shortage.“ The use of pig organs from genetically modified donor animals is considered a promising solution. Such an organ transplant from an animal to a human is called xenotransplantation. An interdisciplinary team at MHH is now working on the new project „Xenotransplantation in Lower Saxony“ (XeNid) with the goal of introducing xenotransplantation as a treatment option into routine clinical practice. The state of Lower Saxony and the Volkswagen Foundation are supporting the four-year project with approximately four million euros as part of the „zukunft.niedersachsen“ program. „We want to establish the resources, methods, and concepts needed to enable genetically modified pig organs to temporarily replace human organs until a human organ becomes available,“ says Prof. Dr. André Bleich, director of the MHH Institute for Laboratory Animal Science and the Central Animal Laboratory at MHH. He coordinates the project together with Privatdozent (PD) Dr. Philipp Felgendreff, MHH Department of General, Visceral, and Transplant Surgery. The team has set itself the goal of laying the groundwork to provide new treatment options for patients with organ failure who have no chance of receiving a life-saving transplant. For example, the team plans to offer liver dialysis using genetically modified pig livers for people with acute liver failure. In addition, the team aims to improve the transplantation of pig heart valves seeded with human cells to prevent chronic rejection reactions. The researchers also aim to make progress in the area of lung therapy. Patients and their representatives are being involved in discussions regarding the study design, ethical considerations, and the interpretation of the results. For xenotransplantation to become part of routine clinical practice, many questions must be answered—ranging from the breeding of suitable animals to the control of the recipient’s immune response and the actual transplantation. Pigs are particularly well-suited as organ donors because their organs are comparable to human organs in many biological characteristics. However, to prevent rejection by the human immune system, the animals must be genetically modified. „We hope that xenotransplantation will become a viable treatment option for people who urgently need a life-saving organ and for whom time is running out due to the shortage of human donor organs. The XeNid project is an important step toward providing these patients with a potential treatment option,“ says PD Dr. Felgendreff. In Germany, xenotransplantation of whole organs has not yet been performed on patients. In the U.S., the first clinical applications are taking place in exceptional cases, as so-called individual therapeutic trials for patients who would have no chance of receiving a human donor organ without xenotransplantation. Since February 2025, two U.S. biotech companies have been conducting clinical trials involving humans who are receiving kidney transplants from genetically modified pigs. SERVICE A movie On the topic („Xenotransplantation—The Medicine of the Future?“), you can find here. Text: Bettina Bandel
Pig Organs as Temporary Replacements
Goal: Xenotransplantation in Everyday Clinical Practice