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Pigs have been the most recent research focus to address the organ shortage, but among the hurdles: A sugar in pig cells, foreign to the human body, causes immediate organ rejection. The kidney for this experiment came from a gene-edited animal, engineered to eliminate that sugar and avoid an immune system attack.
Surgeons attached the pig kidney to a pair of large blood vessels outside the body of a deceased recipient so they could observe it for two days. The kidney did what it was supposed to do — filter waste and produce urine — and didn't trigger rejection.
“It had absolutely normal function,” said Dr. Robert Montgomery, who led the surgical team last month at NYU Langone Health. “It didn’t have this immediate rejection that we have worried about.”
This research is “a significant step,” said Dr. Andrew Adams of the University of Minnesota Medical School, who was not part of the work. It will reassure patients, researchers and regulators “that we’re moving in the right direction.”
The dream of animal-to-human transplants — or xenotransplantation — goes back to the 17th century with stumbling attempts to use animal blood for transfusions. By the 20th century, surgeons were attempting transplants of organs from baboons into humans, notably Baby Fae, a dying infant, who lived 21 days with a baboon heart...
Background
Solid organ transplantation has been, by most measures, a phenomenal success. Nonetheless, the field is plagued by extreme shortages of available organs from a very limited number of donors. One potential solution to this organ availability crisis is the use of animals as organ donors for humans (xenotransplantation). Though the concept remains theoretical, significant advances are being made in the field of genetics and in our understanding of the immunological barriers to xenotransplantation. With these advances also comes increased knowledge about the potential risks of xenotransplants, especially disease transmission. The eventual clinical application of animal-to-human transplants will require a careful, balanced appraisal of these issues.
Organ transplantation has been one of the phenomenal success stories of the latter part of the 20th century. For decades the province of a few bold researchers and clinicians who often captured the public's attention, this field is now solidly entrenched in modern medical therapy. Since the early 1980s, hundreds of thousands of patients have received new kidneys, livers, and hearts. Other organs (lung, pancreas, and intestine) are also routinely transplanted, albeit in smaller numbers. The clinical results of these interventions have meant the restoration of meaningful, productive, and active lives to recipients of all organs.
Vexingly, the transplant community has not been able to meet the demand for donor organs that these clinical successes have generated. To be sure, increases in donor organ availability have been noted over the last decade. But these have been explained by an increase in “living” donors (primarily for kidneys but to some extent for livers and lungs) and by the increasing use of cadaver donors that, years ago, would have been deemed unsuitable (the so-called “marginal” or “expanded” donors). The gap between organ need and organ availability continues to widen despite very substantial public education efforts on organ donation (5) (Figure ?(Figure11). Deaths on the waiting list occur at a rate of 10 patients a day, and patients' waiting times for all major organs continue to grow.