The scramble to find kidneys for transplants or the long waits on a list amid a usable organ shortage could come to an end in the future. The use of gene-edited pig kidneys could vastly increase supply and help meet life-saving demand for patients, Robert Montgomery, MD, PhD, the director of the NYU Langone Transplant Institute explained during an Aug. 16 press conference.
In 2021, Dr. Montgomery performed the first genetically modified pig kidney transplant in a human decedent and has continued his research which has led to a fifth transplant procedure, performed just this July.
So far, one month into the observation of the decedent organ recipient, Dr. Montgomery confirmed that "the one-month kidney biopsies and kidney tests show no evidence of rejection and normal renal function and clearance of toxins," he said during the press conference. "The pig kidney appears to replace all of the important tasks that the human kidney manages."
The research team still plans to monitor the decedent for another month, but these preliminary findings have moved this field of research closer to a possible living human clinical trial in the future, they explained.
"We think that the pig kidney likely requires less genetic manipulation to be accepted by the human immune system than, for instance, a pig heart," Dr. Montgomery said. "The pigs that were used to produce the kidney used in this study are bred; they're not cloned — which means that the gene edits are stable and consistent between pigs, and there's no variation in the dose of the edits. And because they're bred and not cloned they can be scaled much more easily to provide an unlimited source of kidneys for patients who need them."
He noted that the herd of pigs with the single gene edit was approved by the FDA as a source of meat for people who suffer from a rare disorder known as Alpha Gale hypersensitivity, and the pigs are closely surveilled and monitored for pathogens in zoonosis.
Alpha Gale is a trait that was lost through evolution in humans over time, but it still exists in animals and if introduced into the human body, the immune system responds to attack it, which is why there has previously been a barrier to transplants of this kind, he explained. But this specific herd of pigs has been edited to remove that trait, which removes one barrier for transplants like this to be rejected by the human body.
The pig's thymus, a gland in the throat, was also placed under the covering of the kidney for several months prior to the transplant which "has been shown to help protect the kidney from being attacked by the human immune system," Dr. Montgomery confirmed.
Immunosuppressive drugs were also used, but he noted that nothing that was not already FDA approved was used in the study.
Next, Dr. Montgomery said more research will need to be done to understand how to manage a living patient recipient of a pig kidney. He hopes these safe, effective results help move research forward to future clinical trials.
"We have some work to do in terms of ensuring that we're doing this as safely as we can for living recipients and that we're going to provide good quality of life and life years to anybody who receives a pig kidney and that we have the best information we can as to how to appropriately manage patients after they receive a pig organ transplant, as opposed to a human transplant," he said.