Kidney transplant from pig to brain-dead man in Manhattan hospital may help address organ donation shortage, doctors say

A kidney from a genetically engineered pig was transplanted into the body of a brain-dead man and has functioned for the last month, a scientific feat doctors say could help solve the critical shortage of organs for people facing life-threatening disease. 

The 30-minute transplant procedure took place July 14 at NYU Langone’s Manhattan campus and was conducted by a medical team led by Dr. Robert Montgomery, chair of the Department of Surgery at NYU Langone and director of its Transplant Institute. Kidneys filter waste from the blood and regulate blood pressure, among other functions; no animal kidney has been sustained this long in a human, team members said. They plan to continue the experiment for another month. 

“This is the latest milestone in our journey to create an unlimited, sustainable source of organs for transplantation,” Montgomery said at a Tuesday morning news conference.

Nearly 20 Americans die each day waiting for an organ. According to the United Network for Organ Sharing, or UNOS, the non-profit that serves as the nation’s transplant system under contract with the federal government, 23,125 transplants took place from January to June this year, with 103,520 people awaiting transplant. 

The predicament for kidney patients is unique, because they comprise about 80% of the Americans waiting for transplants. Hundreds of thousands more survive on kidney dialysis. 

Experts say that xenografting, or transplanting tissue from one species to another, could be a solution, but the human body’s natural rejection of foreign tissue and the risk of infection pose challenges. 

Montgomery said his team’s work had suggested a path forward, though human trials will still be needed. “With appropriate immunosuppression and gene editing, we can get a kidney past that adaptive response, and then take over all the functions a human kidney does,” he said. 

In an interview, Dr. Adam Griesemer, a member of the NYU Langone transplant team, said that on the morning of the procedure, he and a colleague visited a Virginia farm where Revivicor, a regenerative medicine company based in Blacksburg, keeps a herd of modified pigs. Their genes had been edited to prevent expression of alpha gal, a carbohydrate that can cause organ rejection because it provokes a powerful response from the human immune system.  

Griesemer and his colleague removed the pig kidney in 90 minutes, then wrapped it in sterile bags and ice. They carried it to Manhattan in a cooler. 

At the hospital, members of NYU Langone’s 10-person medical team were waiting with the body of Maurice Miller, a man in his 50s who’d recently died of a brain tumor. Miller’s sister, Mary Miller-Duffy, had agreed to donate her brother’s body for the project. His body was maintained on a ventilator, his heart still beat, and his kidney had been removed.  

When the pig kidney was grafted to Miller’s blood vessels, Griesemer said, it turned from pale to pink. Black or purple would have signaled Miller’s immune system was rejecting the organ. “The immune response, at least initially, was under control.” 

A month later, Miller’s new kidney is still working, the doctors said. “He would be proud of the fact that in the tragedy of his death, his legacy will be helping many people live,” said Miller-Duffy, at the news conference. 

In an interview, Leonard Achan, CEO of LiveOnNY, a nonprofit that advocates for donation and helped connect Miller-Duffy to the NYU Langone project, said animal organs were unlikely to eliminate the need for donated ones, but would alleviate a pressing need: “We need a lot more kidneys in this country than we’re getting.”   

The NYU Langone project was not the first to use xenotransplanting. In 2021, Montgomery led a team in what they said was the first investigational transplant of a genetically engineered pig kidney into a deceased human body. That donor was maintained for 54 hours with no sign of organ rejection.

In 2022, a 57-year old-man who was the first person to receive a genetically modified pig's heart ; he died two months after the transplant surgery at University of Maryland School of Medicine. 

Dr. David Klassen, UNOS chief medical officer, said the medical field would need more data from this project and others like it to determine how well a grafted kidney “can mimic human function and can that be sustained over periods of time."

Dr. Nabil Dagher, director of Northwell Health’s Transplant Institute, called the recent NYU Langone work “a great next step” in transplant research. “The longer that we can prove these kidneys can be sustained in the human body, working normally and taking over the function of the kidney in the human, the more survival benefit you give the patient,” he said.