A Setback in the Quest for Cross-Species Transplantation

In a setback for the pioneering field of xenotransplantation, a woman who received a groundbreaking pig kidney transplant underwent surgery to remove the gradually failing organ after just 47 days. Lisa Pisano, the second person to receive a kidney from a gene-edited pig, is now back on dialysis. Her condition remains stable following the operation earlier this week at NYU Langone Health.

The transplant was a daring attempt to address the critical shortage of human donor organs, which has left thousands of patients languishing on transplant waiting lists. Pisano's case followed that of Richard "Rick" Slayman, the first recipient of a pig kidney transplant at Massachusetts General Hospital. Tragically, Slayman passed away nearly two months after his procedure, though his death was unrelated to the experimental transplant itself.

Initially, Pisano's recovery seemed promising after the dramatic double surgeries in April, which involved implanting a mechanical pump to support her failing heart and the subsequent transplantation of the gene-edited pig kidney. However, as Dr. Robert Montgomery, who led the transplant team, explained, "unique challenges" arose in managing both the heart pump and the new kidney.

Pisano's blood pressure dropped too low multiple times, compromising optimal blood flow to the transplanted organ. Despite their best efforts, the kidney's function gradually deteriorated, prompting the difficult decision to remove it and discontinue Pisano's immune-suppressing medications.

A recent biopsy of the explanted kidney revealed no signs of rejection, a significant concern in such experimental cross-species transplants. However, there was "significant injury" due to insufficient blood flow, according to Montgomery. NYU researchers plan to further study the kidney to gain valuable insights into how it reacted within a living human host.

Montgomery acknowledged that Pisano's heart disease precluded her from being a candidate for a traditional kidney transplant, while her need for dialysis disqualified her from receiving the life-prolonging heart pump. "We are hoping to get Lisa back home to her family soon," he said, praising her "strength and bravery in the face of adversity" as a driving force for the team's continued pursuit of xenotransplantation's "hope and promise."

Pisano herself had expressed awareness of the risks involved, telling the Associated Press in April, "I just took a chance. And you know, worst case scenario, if it didn't work for me, it might have worked for someone else."

With over 100,000 individuals on the U.S. transplant waiting list, most in need of a kidney, and thousands losing their lives while waiting, the quest for alternative sources of donor organs remains a pressing priority. Several biotech companies are genetically modifying pigs to make their organs more compatible with the human body and less likely to trigger immune rejection.

While formal studies of such organs are expected to commence next year, research teams like those at NYU and the University of Maryland have already undertaken temporary transplants of pig kidneys and hearts into brain-dead bodies, yielding promising results. However, the recent setbacks underscore the significant challenges that lie ahead in this pioneering field, where every case represents a crucial step toward potential breakthroughs that could save countless lives.