The story of transplants has always been one of altruism. After all, organs can be neither sold nor purchased. They can only be donated as a gift of life.
It is a story that started in 1954, when Dr. Joseph Murray performed the world’s first successful organ transplant at Boston’s Peter Bent Brigham Hospital between identical twin brothers Ronald and Richard Herrick. Richard had been discharged from the US Coast Guard after being diagnosed with end-stage kidney disease, and his identical twin brother, Ronald, was a willing donor. Although they had no certainty it would work, the transplant resulted in eight more years of life for Richard, successful in part because they had the same DNA.
When Ronald died in 2010, Dr. Murray remembered him in a statement published in the American Journal of Transplantation, saying: “we should never forget that he not only saved his brother Richard’s life, but also paved the way for thousands of other transplant recipients throughout the world.”
It is this same ethos that is now pushing forward the burgeoning field of xenotransplantation – the practice of using animal organs for human transplant.
For the past two years, I’ve spoken with surgeons, genetic engineers and patients who have all told me of the hope of using genetically engineered pig donors to help end the organ shortage crisis. In the United States alone, there are more than 100,000 people waiting for an organ at any given moment – most of them in need of a kidney. Every day, 17 people on that list will die, just waiting.
“This paradigm that someone has to die in order for somebody to live is, a broken paradigm. It just doesn’t work,” said Dr. Robert Montgomery, director of the NYU Langone Transplant Institute. As both a transplant surgeon and a heart transplant recipient himself, he knows how agonizing the wait can be. It’s why he’s relentlessly pushing for a new source of organs.
“Because less than 1% of the people who die every year die in a way that they could ever even be considered as organ donors, we need a sustainable, renewable source of organs from something else other than humans dying,” Dr. Montgomery told me.
In many ways, the idea of using pigs is not all that far-fetched. After all, we have been using pig heart valves to replace human valves since the 1970s. The drugs heparin and insulin were initially derived from pigs. Because of their similarity in size to humans, a pig’s organs are a pretty good match for us. And our long history of breeding them and their ability to produce large litters in just under four months makes them a reliable, steady and speedy source of potential organs.
It was the more recent development of CRISPR and genetic engineering that has truly accelerated the field of xenotransplantation. Scientists can now modify a pig’s DNA so that its organs are more compatible for human transplant, controlling for rejection, growth and possible viruses.
But just as with the Herrick brothers, all of this heady science requires pioneering patients willing to take the chance and raise their hands despite the unknowns.
Sixty-six-year-old Tim Andrews had been on dialysis for two years. He had end-stage kidney disease, and the likelihood that he would get a transplant was extremely low in part because of his rare blood type. Doctors put the chances of him finding a match within the next five years at just 9%. The likelihood of him dropping off the list altogether in that same time period because of illness or death was nearly 50%.
Dialysis had worn on Tim so much that he had resigned himself to the idea that he might literally die in the dialysis chair.
For those not on dialysis, it can be hard to understand just how grueling it can be, both mentally and physically. But think of it like this: Our kidneys are always working, filtering blood 24/7. A dialysis machine tries to do all that work, but compresses it into three or four days a week, a few hours each time. It was so stressful on Tim’s body that he had a heart attack six months after starting dialysis.
When he learned that his hospital, Massachusetts General Hospital, had performed the first experimental pig kidney xenotransplant, he told his doctor, Dr. Leonard Riella, that he had to be given a chance.
Even though he knew there was tremendous uncertainty about the outcome of the transplant, Tim pushed forward. When I visited Tim and his wife, Karen, at their home in Concord, New Hampshire, he told me, “It may shorten your life, but you’re going to do something for humanity. And I’m like, oh, God, that’s what it’s all about.”
At the time, 53-year-old Towana Looney was the only person in the world who could understand what Tim was contemplating. Twenty-five years earlier, Towana had donated one of her kidneys to her mom, but two years later, she developed pre-eclampsia during pregnancy, and her remaining kidney was damaged. Like Tim, she was unlikely to find a match anytime soon, in her case because of high antibodies. She had been on grueling dialysis for eight years before undergoing the transplant in November 2024 at NYU Langone. Dr. Montgomery was her transplant surgeon. Her life was transformed, and when I saw this vibrant womaen on stage talking about her experience, I was amazed at how healthy she looked. Afterward, Dr. Montgomery told me, “She wants to start a revolution.”
In April of this year, Towana had to have her kidney removed after she developed an infection unrelated to the organ that required her immunosuppression regimen to be lowered. At the time, she had lived with the genetically modified pig organ for 130 days, the longest period of time ever recorded.
In a statement, Towana said, “I’m so grateful to have been given the opportunity to be part of this incredible research. For the first time since 2016, I enjoyed time with friends and family without planning around dialysis treatments. Though the outcome is not what anyone wanted, I know a lot was learned from my 130 days with a pig kidney—and that this can help and inspire many others in their journey to overcome kidney disease.”
These are still early days, and so there will be ups and downs, but in science, like life, you learn just as much from the failures as the successes. Each step forward has been building on the lessons learned from previous patient pioneers, like David Bennett and Lawrence Faucette. They both received pig hearts and lived an additional six to eight weeks. Rick Slayman and Lisa Pisano received pig kidneys in 2024, and both lived about two additional months after their procedures. In each case, their stories taught scientists valuable and transformative lessons about the field of xenotransplantation.
This spring, I had a chance to visit with Brittany Rydel, Lisa Pisano’s daughter. She told me, “My mom always cared about other people. And one of the first things she said to me was, ‘Even if this doesn’t work for me, it can work for someone else.’ And I think about that a lot. You know, I might need a kidney one day. My kids might need a kidney one day. “
The baton of altruism and hope passed on again.
So often, it is the scientists and the researchers who are recognized – and for good reason. After all, the story of xenotransplantation is possible because of several Nobel Prize-winning discoveries, including transplanation, gene editing, cloning, IVF and immunology. As Dr. Montgomery told me, “We stand on the shoulders of giants for sure.”
The real giants propelling this field forward, however, are the patients bravely stepping into the unknown for the benefit of all of us.