TUESDAY, Aug. 26, 2025 (HealthDay News) — Doctors in China transplanted a genetically modified pig lung into a man, where it functioned for nine days, according to a new study published in the journal Nature Medicine.

Researchers at Guangzhou Medical University’s First Affiliated Hospital performed the surgery on a 39-year-old man who had been declared brain-dead after a brain hemorrhage. His family gave consent for the procedure, CNN reported.

This is believed to be the first attempt to transplant a pig lung into a human. While scientists see hope in this type of surgery, experts say it could take years before it’s an option for people who need lung transplants.

The pig lung used in the transplant had six gene edits that were designed to reduce the risk of rejection. The donor pig was raised in a highly controlled, sterile environment.

Doctors also gave the patient several medications to lower the chances of infection and rejection.

At first, the lung showed no immediate signs of rejection. But within a day, the patient developed widespread swelling as fluid built up in his tissues, possibly caused by blood flow problems.

Although there were signs of partial recovery after a few days, doctors later saw that the man’s body had started rejecting the organ. At the family’s request, the experiment was stopped.

“Although this study demonstrates the feasibility of pig-to-human lung xenotransplantation, substantial challenges relating to organ rejection and infection remain,” the researchers wrote.

Organ shortages remain a critical issue.

In the United States, more than 103,000 people were waiting for transplant organs, according to federal data collected last fall. But fewer than 48,000 transplants were performed in 2024. About 13 people die each day waiting for an organ.

Doctors have successfully transplanted pig heart valves into humans for decades, and there’s been recent progress with genetically modified pig kidneys and hearts, CNN said.

But lungs present unique challenges because they are constantly exposed to bacteria and viruses.

Experts note that the lungs are central to the body’s immune defenses, but protecting them remains a challenge, even with great advances such as transplants.

Other scientists say using pig organs could eventually help close the gap between available organs and patient needs.

Researchers wrote that there is “transformative potential” in xenotransplantation, the process of transplanting organs or tissues from one species to another.

A Chicago transplant surgeon who reviewed the findings reacted cautiously in an interview with CNN.

“We’ll learn something from this, but I’m not fully convinced that this really opens up the doors to doing bigger trials, just based on what we observed here,” said Dr. Ankit Bharat, chief of thoracic surgery at Northwestern Medicine in Chicago.

Dr. Adam Griesemer, a transplant surgeon at NYU Langone in New York City who also reviewed the study findings, agreed that more research is needed.

“Nobody would sign up for a nine-day lung transplant,” he said.

Researchers are also exploring new options, such as using pig lungs as “scaffolds,” swapping them out with human cells using stem cell therapy. This approach could one day make organs less prone to rejection.

For now, most experts say pig lung transplants remain experimental.

More information

The National Kidney Foundation has more on xenotransplantation.

SOURCE: CNN, Aug. 25, 2025