New hope for renewal: Pig kidney transplants could save human lives

Pigs are called many different names in American folk culture. Porky, Arnold, Babe, Miss Piggy and the Three Little Pigs are among the more prominent.

Usually, “lifesaver” isn’t one of them.

Yet the first transplant of a pig kidney into a living human being brings great hope that this approach — known as xenotransplantation, the use of animal organs in human recipients — will save many more lives in the years ahead.

In Boston, 62-year-old Richard Slayman, suffering from end-stage renal failure, received a pig’s kidney during a four-hour operation on March 16 and appears to be recovering well. The pig’s organ carried gene changes, called “edits” by scientists, that prevented rejection in Slayman’s body and lowered his risk of possible deadly infection.

This news is truly historic. In recent years, impressive developments in modern medicine have emerged from the study of DNA and genetic codes in living organisms, including humans, and how that can help fight illness and other health problems. Xenotransplantation, this latest step, involves genetically modifying the donor pig to achieve compatibility with the human body during surgery. Pigs are favored animals for organ transplants because of their abundance, and their similar size and blood flow to humans. The procedure is still far from perfect. Patients receiving xenotransplants in the foreseeable future will still need anti-rejection medications, like most who receive human transplants.

PIG HEARTS ALSO TRIED

In this new world, kidneys are not the only porcine organs being used on an experimental basis. Two very ill patients at the University of Maryland received pig hearts in separate surgeries in January 2022 and September 2023 under “compassionate” use provisions approved by the U.S. Food and Drug Administration. The first patient survived for 60 days and the second died after nearly six weeks.

To further understand this process, surgeons at NYU Langone Health in Manhattan reported last July on transplanting gene-edited pig hearts into two brain-dead human recipients — a man and woman who had consented previously to full-body donation. These NYU doctors found “excellent cardiac function” in these pig organs during the period studied. Despite this hopeful evidence for the future, the NYU doctors advised more research is needed before experimental trials of pig heart transplants to live humans can begin.

By relying on scientific evidence and the advice of doctors, the FDA is to be credited for opening the door in 2022 to this extraordinary process of interspecies transplantation. There are some ethical concerns to consider — including who will receive these expensive operations should they be approved for general use by the FDA. But the most imperative concern should be the saving of human life. That’s why this month’s pig-human transplant in Boston is so noteworthy.

Overall, thousands of patients like Slayman are waiting to be saved with a new functioning kidney. According to the National Kidney Foundation, there are 37 million Americans with chronic kidney disease, about 600,000 living with kidney failure, and 100,000 on the transplant waiting list. Though many good-hearted living donors offer one of their two kidneys to a recipient (in addition to kidneys from deceased donors), there are still far too few available kidneys — and far too few donors — for the overall need. Seriously ill patients waiting for a new kidney usually rely on regular dialysis treatment for several years. In the worst cases, patients die before they can get a new kidney, the fate of more than 3,000 Americans annually.

DONOR SHORTAGE

Because of these life-and-death questions surrounding transplants today, the United Network of Organ Sharing manages the waiting list for kidney and other organ transplants to make sure they are given out fairly. In the U.S. during 2023, there were only 23,286 human organ donors. Of these, more than 16,000 were deceased donors who had agreed in advance to allow their organs to be used, the network said. Unfortunately, 103,858 people still remained on the organ waiting list, hoping for lifesaving transplants.

In New York State, about 8,000 New Yorkers are on the national waiting list for organ transplants — the vast majority of them (about 7,000) waiting for a kidney, according to state health officials. Each year, nearly 500 New Yorkers die because there weren’t enough available donated human organs.

The recent COVID-19 crisis — when many hospitals temporarily shut down their transplant operating rooms because of infection worries — dramatically illustrates how desperate the overall need can be. One 2022 study found that mortality for New York City kidney transplant candidates was 2.5 times higher after the national COVID emergency began compared to before. If more transplants were available because of a new reliance on genetically-modified pig organs, could this crisis have been somehow abated?

This longtime shortage in available human donated organs makes the news of Slayman’s pig kidney transplant so heartening to many doctors, patients and their loved ones. If Slayman has a good long-term outcome, it will be another step toward FDA approval of full-scale clinical trials. Ever since South African surgeon Christiaan Barnard conducted the first human heart transplant in 1967, medicine has been on a long journey discovering the capability of transplant surgery to extend and improve human life. This recent move toward interspecies transplants with pigs is one more welcome step in that direction.