Looney was running out of options. Her health was failing, and after years of searching, the chances of finding a matching human kidney were slim. Her doctor, Jayme Locke, then an abdominal transplant surgeon at the University of Alabama at Birmingham, had previously performed short-term pig kidney transplants in brain-dead recipients and suggested the experimental procedure as a last resort. Looney’s transplant was approved under the U.S. Food and Drug Administration’s compassionate operate program, where unapproved treatment is the only option for a patient with a earnest or life-threatening condition.
Locke partnered with Robert Montgomery, director of the Langone Transplant Institute at Recent York University, to perform Looney’s seven-hour surgery. Locke is currently the director of the Division of Transplantation at the U.S. Health Resources and Services Administration, part of the Department of Health and Human Services.
Locke said Tuesday that Looney will spend the next three months in Recent York to monitor her closely before returning home to Alabama.
Looney received a kidney from a pig with 10 genetic changes developed by Revivicor, a subsidiary of United Therapeutics. Three pig genes known to trigger an immune response were deleted, as well as the porcine growth hormone receptor. To reduce the likelihood of rejection, six human genes were added.
Due to genetic differences between pigs and humans, researchers have turned to gene editing to make pig organs more compatible with the human body. However, there is an ongoing debate in the field of xenotransplantation about how much genetic change is needed to make a pig’s organ work long-term in a human. For Pisano’s procedure earlier this year, the Recent York University team used a donor pig with a single genetic modification — a gene knockout designed to eliminate the alpha-gal sugar from the surface of pig cells. This sugar causes rapid rejection of pig organs in humans. This donor pig also came from Revivicor.
The Massachusetts team took a different approach to Slayman’s surgery and opted for a pig with 69 genetic changes from the biotechnology company eGenesis. “These distinctions highlight the continuing evolution of xenotransplantation strategies and the potential benefits of increasing compliance through more extensive genetic modifications,” says Leonardo Riella, medical director of kidney transplantation at Mass General.
Pig organ recipients still need to take immunosuppressive drugs to prevent the novel organs from being rejected by their immune systems.