The study’s authors also acknowledged several outside factors may have influenced the results: The pig had been genetically modified to reduce the risk of rejection, and the recipient was given a host of antibodies to suppress immune response. The recipient also already had another lung, which could have influenced immune response and the donor lung’s function.
The observation period in the Guangzhou study also wasn’t long enough to determine whether the body might reject the organ later, Bharat says. “A short-term success, even if you have a lung that survives a day or two, does not necessarily translate into shorter or long-term success,” he said. Nevertheless, the transfer will likely further scientific understanding of pig lung xenotransplantation, Bharat added, which has mostly been tested on non-human primates.
Despite the potential benefits to human recipients, raising animals in labs purely for their organs, and experimenting on brain-dead patients who can’t vocalize consent, present complicated bioethical concerns, says Insoo Hyun, an affiliate at the Harvard Medical School Center for Bioethics. “It’s a call that the institution makes, and the ethical reviewers have to make,” he said.
And even if it’s proven to be safe and viable for humans, xenotransplantation could eventually lead to a “two-tiered system” in which some patients get animal organs while others get human ones. And if it turns out there are differences in quality between the types of organs, he noted, “if [there is a] second-best option, who gets the second-best one?”
