Doctors at the University of Alabama, Birmingham implanted two pig kidneys into a brain-dead person in September, a step toward trying the procedure in a person.
The surgery was not made public until Thursday when the results were published in a scientific paper.
The surgery marked the second time a pig kidney was implanted in a brain-dead person. The first took place five days earlier at NYU Langone Health in New York City.
This month, a Maryland man received a pig heart as a last-ditch effort to save his life.
In all three cases, the pig donor had its genes edited to make the human body less likely to reject it.
The experiments with deceased recipients were intended to show that the body would not immediately reject the organ, as would happen with an animal that didn't have such genetic changes.
At UAB Hospital, the recipient, Jim Parsons, 57, had been declared brain dead but was maintained on a ventilator. Parsons, of Huntsville, Alabama, was involved in a dirt bike accident in late September that left him unable to recover.
His organs were not viable for donation, but his family allowed his body to be used in the study.
Parsons' children and ex-wife, with whom he remained close, gave permission for the procedure. "She said it would have meant a lot to Mr. Parsons to know that he was able to do something that was completely different and could potentially benefit so many,” said Alan Spriggs, program manager with Legacy of Hope, Alabama’s organ procurement organization.
Parsons had celebrated his 57th birthday days before the accident and had returned from a trip riding motorcycles to and from the mountains of Colorado with one of his three children.
“I didn’t realize how thankful I was for that trip until after he passed away," his son David said in a statement released by the hospital. “That was a trip he wanted to take us on his whole life, and I’m thankful for it.”
In the operation Sept. 30, Jim Parsons' kidneys were replaced with two from a gene-edited pig raised in a pathogen-free facility established by UAB.
They remained in place for about 77 hours before "brain death won the game" and Parsons' body became too unstable, Dr. Jayme Locke, director of the Comprehensive Transplant Institute in UAB’s Department of Surgery and lead investigator for the study, said at a news conference.
The pig had 10 gene edits to prevent rejection once the kidneys were implanted, to keep them from growing too large inside the human body and to prevent blood clots.
UAB envisions using pigs with the same edits in a clinical trial, which it hopes to begin this year.
So-called xenotransplantations are intended to help solve the human organ shortage. People in need of a heart, kidney or other organ often have to wait years, if they get one at all. Their second chance comes at the expense of someone else, who had to die and donate organs.
More than 100,000 Americans are on organ transplant waiting lists, and some never qualify at all. About 6,000 die every year while waiting. Experts expect that demand will skyrocket if pig organs can be safely made available.
"The problem is bigger than the numbers suggest," Locke said. "We think it needs a radical solution."
UAB has a particular interest in solving the organ crisis because the hospital is located in the "stroke belt," and many of its patients are minorities, Dr. Selwyn Vickers, dean of the UAB Heersink School of Medicine, said Tuesday. UAB, he said, has performed more organ transplants in Black Americans than any other institution and the second highest number of transplants overall in the past 30 years.
Before the procedure was performed, it was approved by a hospital review board and subjected to an external ethics review.
Over the next year, UAB will raise enough gene-edited pigs for clinical trials. An early stage trial, which the hospital hopes will be approved by the Food and Drug Administration this year, would include 10-20 transplants into people. Later stage trials would include hundreds of patients.
UAB is working with kidney and heart transplants and hopes to expand to lung and liver transplants, Locke said.
Others work to make pig organs available for transplant.
"This case demonstrates another opportunity to learn more about xenotransplantation," Robert Montgomery, the surgeon who performed a similar procedure at NYU in September and again in November, said in a statement. "I'm particularly interested in what new information we can learn about the function of the kidneys given the significant differences in the genetic modifications and transplantation process from the studies we performed."
If early trials can be started this year and all goes well, Locke said, she expects xenotransplantation will become more widespread.
"If we hit every milestone with no setbacks, (in) five years, we could be ready to offer this to the masses," she said.
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Contact Karen Weintraub at firstname.lastname@example.org.
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This article originally appeared on USA TODAY: Pig organ transplant: Alabama doctors implant gene-edited kidneys