Surgeons at the University of Alabama have successfully transplanted two pig kidneys into a brain-dead man.
Last year, researchers in New York made headlines for temporarily attaching a pig’s kidney to blood vessels outside a brain-dead patient’s abdomen. Then earlier this month, doctors at the University of Maryland conducted the first pig-to-human heart transplant. Now a team at the University of Alabama have attempted transplanting two genetically modified pig kidneys into a brain-dead human patient. They aimed to develop a model for future transplants in alive patients and assess the trial’s safety and feasibility. The researchers outlined their experiment in The American Journal of Transplantation.
Surgeons used the donated body of 57-year-old Jim Parsons who was declared brain-dead after a racing accident.
The Challenges of Xenotransplantation
To overcome the obstacle of organ rejection, researchers used genetically modified pig kidneys. Similar to the recent transplant involving a pig’s heart, the team made 10 genetic modifications to the organs. This involved removal of four pig genes and the addition of six human genes into the pigs. While the human genes helped prevent rejection, the removal of genes helped prevent the growth of pig tissue. Thus, the organs remained viable until 77 hours until the experiment’s termination. Furthermore, the researchers did not note
Another hurdle in xenotransplantation – transfer of organs from animals to humans – is the difference in blood pressures between the two species. Pigs and other animals usually have lower mean arterial blood pressures than adult humans. Therefore, there is a risk of hemodynamic instability. However, the blood vessels within the pig kidneys successfully held up against the higher pressures. Furthermore, the researchers did not report any pig viruses or pig cells within the patient’s bloodstream.
Porrett, Paige M., et al. “First Clinical‐Grade Porcine Kidney Xenotransplant Using a Human Decedent Model.” American Journal of Transplantation, 2022, doi:10.1111/ajt.16930.