Surgeons in China have transplanted a genetically modified pig lung into a brain-dead human recipient for the first time, and it remained functional for nine days. The procedure, reported in Nature Medicine, represents a significant step in xenotransplantation, a field focused on addressing the global organ shortage, which currently meets only around 10% of demand, according to the World Health Organization.
The lung came from a Chinese Bama Xiang pig with six genetic modifications designed to reduce the risk of rejection. In the 39-year-old brain-dead recipient, the organ avoided hyperacute rejection and showed no infection over 216 hours. However, fluid accumulation and progressive antibody-mediated damage occurred despite strong immunosuppressive therapy, highlighting the remaining challenges.
Challenges of Lung Xenotransplantation
Experts note that lungs are especially difficult to transplant because they are constantly exposed to the external environment, making them highly sensitive to infection and inflammation. Andrew Fisher of Newcastle University emphasized that having the recipient’s own lung still functional likely masked the true extent of damage to the pig lung.
Peter Friend from Oxford University added that inflammation caused by brain death complicates results, making it harder to isolate the lung’s response from the recipient’s condition.
Future Directions
Researchers stressed that further refinements are needed, including optimizing immunosuppressive regimens, improving genetic modifications, enhancing lung preservation techniques, and monitoring long-term graft function.
While xenotransplantation research has also involved kidneys, hearts, and livers, lungs remain particularly challenging. Alternative strategies being explored include:
- Stem-cell remodeling of marginal human donor organs to make them suitable for transplant.
- Growing humanized organs in pigs or sheep.
- Reconditioning human lungs initially deemed unsuitable for transplantation, which could provide a faster solution to the organ shortage.
Experts agree that while the lung transplant is promising, practical use in living patients is still some years away, and further research is essential before pig lungs can be routinely used in clinical settings.
