Researchers have successfully attached a pig kidney to a human recipient where it functioned for three days – in a massive leap toward an alternative supply of organs for those desperately awaiting transplants.
The kidney was obtained from a specially engineered pig and attached to a deceased donor by New York University Langone Health surgeons. The patient was maintained on a ventilator, with the family’s consent, and observed for 54 hours to study the kidney’s function and watch for signs of rejection. During this time, the organ successfully filtered waste from the person’s body.
Dr. Robert Montgomery, Professor of Surgery and chair of the Department of Surgery at NYU Langone, says: “This is a transformative moment in organ transplantation.” Although he is reflective when it comes to the sacrifice the family of the donee made, adding: “The family graciously approved donation of their loved one’s body for this procedure. That extraordinary generosity paved the way for this major step forward in creating a sustainable supply of lifesaving organs and hopefully ending the current paradigm that someone has to die for someone to live.”
In the United States, 17 people die every day while on the national transplant waiting list, according to the Health Resources & Services Administration. Governments worldwide have directed much investment to solve this shortage by using animal organs in a procedure called xenotransplantation.
Pigs are a popular choice here because they’re already raised for food, produce large litters within a short period and grow anatomically similar organs to humans. But there’s one major hurdle: pigs carry a gene that codes for a sugar molecule called alpha-gal, which causes severe immune reactions in humans, including organ rejection.
Previous studies devised ways of disabling this gene to transplant pig’s kidneys into nonhuman primates, where they functioned for over a year. These tests have also suggested that when a donor animal’s thymus gland is ‘implanted’ along with its organ, it can help to rewire the donee’s immune system – providing a hospitable transplant environment. Building on this, the present study saw the team knock out the alpha-gal gene in the donor pig and implant the animal’s thymus gland to increase the chances of organ acceptance in the human recipient.
The kidney was then attached to the blood vessels outside the patient’s abdomen, just above their leg, and covered with a protective shield for observation and tissue sampling. Urine production and creatinine level – standard indicators of a properly functioning kidney – were equivalent to those seen in a human kidney transplant. The transplant team detected no signs of rejection and now plans to submit the study results for peer review and publication.
“The potential here is incredible,” Dr. Montgomery says. “If the science and experimentation continue to move ahead positively, we could be close to kidney xenotransplantation into a living human being. And the future of this work is not limited to kidneys. Transplanting hearts from a genetically engineered pig may be the next big milestone. This is an extraordinary moment that should be celebrated—not as the end of the road, but the beginning. There is more work to do to make xenotransplantation an everyday reality.”
Image courtesy of Joe Carrotta for NYU Langone Health
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