Researchers in China’s Greater Bay Area have achieved a world first by transplanting a genetically modified pig lung into a human recipient. In an article published in Nature Medicine earlier this month, the Guangzhou Medical University scientists reported that the transplanted lung remained viable for nine days inside their patient, a 39-year-old brain-dead man.
Their procedure – which took place in May 2024 – marked a significant milestone in the emerging field of xenotransplantation, which means transferring tissues or organs between different species.
Clonorgan Biotechnology, a Chengdu-based company behind the donor pig, inserted three human genes into a breed of pig called a Bama Xiang, while silencing three pig genes in a bid to prevent organ rejection. It has described its mission as creating “the organ factory of the future.”
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The lung sustained function for nine days before the patient’s family requested to end the experiment and remove the lung. Researchers reported no hyperacute rejection. Although antibody-mediated immune responses caused some organ damage on days three and six, these had partially recovered by day nine.
Lung xenotransplantation has long been considered a major challenge. Unlike kidneys or hearts, lungs are constantly exposed to air and environmental pathogens, making them rich in immune cells and prone to rapid rejection – even for human-to-human transplants.
While the global medical community has hailed the Chinese team’s achievement as exciting, there are some caveats.
Dr Richard N. Pierson, a professor of surgery at Harvard Medical School and the Massachusetts General Research Institute, who has done extensive research on pig heart transplants, noted that the experiment didn’t prove the pig’s lung could sustain human life on its own – as the patient’s other lung was functioning simultaneously. “They’ve shown a pig lung can be sewn into a human being and shown what happens,” he said.
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The team itself acknowledged limitations in its Nature Medicine article: “Although this study demonstrates the feasibility of pig-to-human lung xenotransplantation, substantial challenges relating to organ rejection and infection remain, and further preclinical studies are necessary before clinical translation of this procedure,” the authors wrote.
Early attempts at xenotransplantation date back to the early 20th century, including a 1906 pig kidney transplant and a 1909 monkey kidney transplant – both of which failed. Research was largely abandoned until the advent of modern gene editing, thanks to the 2012 development of CRISPR technology.
In 2022, US patient David Bennett became the first human to receive a genetically modified pig heart, and survived two months before succumbing to a viral complication. Pig kidneys and livers have since been transplanted into people, with limited success.
Scientists hope that suitable animal organs will eventually be able to help solve the global organ shortage. According to the World Health Organisation (WHO), only up to 10 percent of transplant needs were being met as of 2022.
