Surgeons have successfully transplanted a genetically engineered pig kidney into a human patient for the first time, marking a milestone in xenotransplantation. The procedure, performed at NYU Langone Health, removed a major barrier by modifying pig cells to prevent immediate human immune rejection.
The global shortage of human organs for transplant patients has long driven research into animal organs, but human immune systems instantly attack foreign tissue. A major obstacle has been a sugar called alpha-gal found in pig cells, which triggers severe rejection. In a procedure led by surgeon Robert Montgomery at NYU Langone Health in New York City, the transplanted organ came from an animal genetically engineered specifically to stop producing alpha-gal.
Operating Room Observations at NYU Langone Health
The initial test took place on a patient who was already brain dead and maintained on artificial life support, allowing the surgical team to observe the organ functioning in real time. While kept outside of the main body cavity during the operation, the modified kidney immediately performed its core biological tasks.
It's even better than I'd hoped,
surgeon Robert Montgomery, who led the transplant at NYU Langone Health in New York City, told USA Today.
Robert Montgomery, surgeon who led the transplant at NYU Langone Health in New York City
During the 54-hour observation window, the surgical team documented that the organ successfully filtered out waste products from the blood and produced urine. Dorry Segev, a professor of transplant surgery at Johns Hopkins School of Medicine who did not participate in the research, told the New York Times that the achievement is a huge breakthrough and a big, big deal.
Addressing the National Organ Shortage
The clinical motivation behind interspecies transplants, or xenotransplantation, is the severe deficit of human donors. Over a hundred thousand people are currently waiting for an organ transplant in the United States alone, where an average of 17 patients die daily while waiting on lists.
Beyond saving patients from fatal outcomes on waiting lists, successfully developing animal organs could assist hundreds of thousands of people who require demanding kidney dialysis routines but do not qualify for high-priority human transplant lists. Martine Rothblatt, chief executive of United Therapeutics—the company that engineered the pig—emphasized the broader societal impact.
This is an important step forward in realizing the promise of xenotransplantation, which will save thousands of lives each year in the not-too-distant future,
Martine Rothblatt, the chief executive of United Therapeutics – the company that genetically engineered the pig – told The Guardian.
Martine Rothblatt, chief executive of United Therapeutics
Clinical Milestones and Next Steps in Xenotransplantation
The broader development of interspecies organ sharing is also moving forward through commercial and clinical channels. Scientists at eGenesis previously looked at primate studies to evaluate what might happen after taking an animal organ out, specifically questioning whether patients would produce antibodies that would complicate a human-to-human transplant later on. According to an announcement by the biotech company, they now have confirmation.
While early human recipients of gene-edited pig kidneys eventually required the removal of their xenografts and went back on dialysis for months before a human organ was available, the fact that two of them could spend the better part of a year not needing to be hooked up to tubes represented a milestone. Regulatory hurdles and ethical debates surrounding animal breeding remain, but pigs offer distinct practical advantages over other animals like monkeys because they are already bred for food, have large litters, short gestation periods, and organs that are similar to human anatomy.
Medical precedent for animal tissue in humans already exists through the use of pig skin grafts for burns and pig heart valves in humans, alongside experiments that have already been carried out with pig hearts in baboons. As yet, there’s no peer-reviewed scientific report of the operation, but experts say trials with pig kidneys on critically ill humans—patients with no real other options left—could happen within two years.
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