Stories of pig-human chimeras – where cells of humans and pigs grow together into one body or organ – and pig-human hybrids made from parts of both species have been becoming more frequent in the U.S. … which leads many to believe that countries without strict regulations are much further along. In April, scientists announced they had successfully grown human muscle tissue in pig embryos that were grown to term – but with cells removed via CRISPR gene editing so no brain cells were merged. This week, doctors in New York City performed another controversial experiment – they attached a kidney grown in a genetically-altered pig to a human and the organ did its job for nearly three days. Is this a sign the day of pig organ farms has arrived?
“It had absolutely normal function. It didn’t have this immediate rejection that we have worried about.”
Dr. Robert Montgomery, spokesperson and leader of the NYU Langone Health surgical team which performed the test, explained that the pig’s cells had been genetically edited to remove a sugar that causes rejection in humans. Outside of that, this was a normal pig’s kidney – not a chimera organ grown from implanting human stem cells in a pig embryo. A controversial experiment of pig-human chimera creation took place earlier this year and resulted in human muscle tissue developing in the pig.
This week’s experiment is controversial for two reasons – the kidney is from a genetically-altered pig bred solely for organ donation and the recipient was a brain-dead woman whose family agreed to allow her body to be used after it was deemed that her organs were not suitable for donations per her wish. The woman’s body was kept alive on a ventilator while the kidney was attached outside of her body. According to the team, it began functioning immediately, making urine and the waste product creatinine, and continued for 54 hours until the experiment was ended.
“This allowed us to answer a really important question: Is there something that’s going to happen when we move this from a primate to a human that is going to be disastrous?”
Make that three controversial reasons – Dr. Montgomery tells The New York Times that the goal is still to use primates as organ donors rather than pigs since their bodies are closer to humans. Besides the standard objections by animal rights proponents to using animals for human experiments, primates kick it to the next level by looking so much like us – we humans are conditioned to accept pigs as dispensable … but killing chimps is still too emotional for most people. That may change as the population continues to age and the demand for kidneys, hearts and other organs increases. NPR interviewed Karen Maschke, a research scholar at the Hastings Center, who will help develop ethics and policy recommendations for the first clinical trials of pig organ implants under a grant from the National Institutes of Health, asks the critical question:
"The other issue is going to be: Should we be doing this just because we can?"