A Human Being Breathed with a Pig’s Lung for Nine Days in a first Xenotransplantation
Experiment in China shows promise but underscores how far xenotransplantation still has to go. In a sterile operating theater at the First Affiliated Hospital of Guangzhou Medical University, surgeons performed a procedure never before attempted. They stitched a lung from a genetically engineered pig into the chest of a 39-year-old man who had been declared brain-dead.
For nine days, the patient’s family watched as machines kept him alive, and as his new pig lung inflated, exchanged gases, and struggled against the inevitable rejection from the human immune system. The experiment, conducted with the family’s consent, was never meant to save his life. It was designed to test a question that has haunted transplant medicine for decades: can animals bridge the desperate gap in the supply of human organs?
The need is stark. More than 100,000 Americans remain on organ waitlists, and across the world, thousands die every year before a suitable donor is found. Lungs are among the rarest organs available. Unlike kidneys, which can be partially replaced by dialysis, patients with lung failure have no fallback option.
In 2024, just over 8,200 lung transplants were performed globally, far fewer than the tens of thousands of patients who needed them. Families watch loved ones tethered to oxygen machines, doctors struggle against time, and patients live in constant fear that the next breath may be their last.
This human crisis has fueled a revival of xenotransplantation. The use of animal organs in humans, as scientists and biotech firms search for sustainable solutions.
The pig lung used in Guangzhou was not an ordinary organ. It came from a Bama miniature pig bred by Clonorgan Biotechnology in Chengdu, genetically engineered with six CRISPR edits. Three pig genes that produce immune-triggering sugars were deleted, while three human genes were added to help regulate inflammation and blood flow.
The surgical team left the patient’s right lung intact as a safety reserve and began a strict regimen of immunosuppressive drugs. At first, there were no signs of hyperacute rejection, which was often the immediate catastrophic immune response that doomed so many past attempts. But by the first full day, the patient’s immune system began fighting back. White blood cells infiltrated the pig lung, fluid filled the tissue and antibody-mediated rejection set in. But, by day nine, the experiment was ended at the request of the family.
“Lung xenotransplantation presents unique challenges compared to other organs. Our aim is not to claim clinical readiness today, but to build a scientific pathway toward a safe and durable lung xenograft.” said Jiang Shi, who led the study.
Unlike hearts or kidneys, lungs are exposed directly to the outside world, making them especially vulnerable. Every breath brings not just oxygen, but also bacteria, viruses and pollutants. To defend against these threats, lungs are wired with multiple immune defenses. These defenses are the very obstacles to foreign organ’s transplant.
Even among human donors, lung transplants were notoriously unreliable until the 1980s, decades after successful kidney and heart transplants. Introducing an organ from another species adds yet another layer of complexity.
The Guangzhou study is part of a broader global race. US-based biotech firms like eGenesis and Revivicor are developing pigs with dozens of genetic edits, including eliminating viruses that might jump into human cells. China has made xenotransplantation a priority, hoping to leapfrog into leadership in the field. If successful, the potential business is enormous.
Analysts predict a multibillion-dollar market opportunity for transplantable animal organs, having awaiting lines of business players like hospitals, insurers, governments, multi-billionaire individual global-change-drivers, etc., who are eager for a reliable supply. But it is also a race shadowed by ethical debates, with a loud question-call, asking if it is acceptable to breed animals as organ banks for humans. And. how much risk should patients and families bear in the name of innovation?
Dr. Shaf Keshavjee – director of the Toronto Lung Transplant Program said – “It’s not ready for prime time. They’ve shown us we’re not there yet. Don’t go trying this on a patient because it ain’t going to work.”
Others note that because the patient’s native lung remained in place, it’s impossible to know how much oxygenation came from the pig’s organ. Richard Pierson, a xenotransplant researcher at Harvard Medical School said –“Their conclusion that they have a functioning pig lung is a little optimistic.”
Still, even critics agree the experiment adds valuable knowledge. Brain-dead patients, researchers argue, offer a unique bridge between animal studies and human trials, allowing science to probe the limits of genetically modified organs without risking lives.
Behind the technical details, lies a human story that sites a family in Guangzhou, who was in the midst of grief yet chose to allow their loved one’s body to be part of this experiment, believing that one day, the results would help people across the globe. And this decision granted them a free-breathe of fulfilment. Because for them, the decision was about more than science. It was about giving meaning to a life cut short; and turning tragedy into a step forward for humanity.
However, the pig lung ultimately failed. But for nine days, it worked well enough to keep hope alive. To the scientists, it was a proof that rejection can be delayed, if not yet defeated. In the aspect of the patients waiting in hospital beds, it was a small sign that a future where animal organs buy them time, or even save their lives, might not be science fiction forever.
The Guangzhou team plans to continue testing pig lungs with more genetic edits and refining immune therapies, as around the world, multi-capacitated labs are also preparing the next wave of experiments to be unraveled.
Remarkably, the first pig lung did not save a life. Nonetheless, it did something almost as powerful as it got. It gave the world a glimpse of what might one day be possible.
