Pig to Human Cardiac Xenotransplantation

Transplantation of organs can be the sole treatment available to patients suffering from declining organ function, but the wait for organ donation can be unfeasibly long, given the demand for organs that far exceeds the availability. Xenotransplant (transplantation of organs from other species) has been suggested as a potential solution to this problem. A recent paper published in the New England Journal of Medicine reports the transplantation of a porcine (pig) heart into a human donor. A patient with severe heart failure in the United States who had been declined heart transplant due to poor adherence to treatment was offered experimental cardiac xenotransplant. The experimental treatment was approved on the grounds that its outcome was unlikely to be inferior to continuing treatment by ECMO (extracorporeal membrane oxygenation) and was approved after multiple institutional evaluations. The porcine heart was derived from a pig that had been genetically treated to minimise immune rejection, and the patient was further treated by immunosuppressants and prophylactic antibiotics. The patient demonstrated no signs of xenograft rejection both functionally and histologically, and initially showed improved cardiac function. However, the patient experienced sudden graft failure for unknown reasons, and life support was withdrawn after 60 days. Post-mortem biopsy demonstrated histological features that were inconsistent with immune-mediated rejection of the transplant organ or virally mediated changes, prompting the authors to continue the search for other reasons that could have caused organ failure (which is as of yet unclear).

Griffith, B. P., et al. (2022). "Genetically Modified Porcine-to-Human Cardiac Xenotransplantation." New England Journal of Medicine 387(1): 35-44.