For the first time, surgeons have transplanted a genetically modified pig lung into a brain-dead human, where it remained functional for nine days. The procedure, described in Nature Medicine, represents a step forward in xenotransplantation, a field aimed at addressing the global shortage of donor organs. According to the World Health Organization, only around 10% of the worldwide demand for transplants is currently met.
The left lung came from a Chinese Bama Xiang pig genetically modified with six alterations to reduce rejection by the human immune system. The recipient, a 39-year-old male, showed no signs of hyperacute rejection or infection over 216 hours. However, fluid accumulation and progressive antibody-driven damage occurred despite immunosuppressive medication. Experts note that the presence of the patient’s own lung may have masked the full extent of the organ’s deterioration.
Challenges of Lung Xenotransplantation
While xenotransplantation has shown success with hearts, kidneys, and livers, lungs pose unique difficulties. “Every breath you breathe brings the external environment into the body,” explained Andrew Fisher, a respiratory transplant expert at Newcastle University. Lungs must manage constant exposure to pathogens and pollution, making them particularly sensitive to immune rejection.
Brain death further complicates research, according to Peter Friend of Oxford University, because it triggers acute inflammation that can influence transplant outcomes. Experts emphasize that while promising, the results represent a “qualified success” and that the lung cannot yet independently sustain a patient.
Next Steps and Future Prospects
Researchers highlight the need to refine genetic modifications, optimize immunosuppressive treatments, and improve lung preservation to enhance long-term viability. Other avenues under investigation include growing humanized organs in animals, remodeling donor organs with stem cells, and reconditioning lungs initially deemed unsuitable for transplant.
Fisher added that treating marginal human lungs could provide more immediate impact, potentially increasing transplant availability within months to years, while xenotransplantation continues to progress more gradually.
This milestone signals progress in the quest to expand organ availability but underscores that routine use of pig lungs in living patients remains a goal for the future, not the present.
