Someday, a Pig-to-Human Organ Transplant Could Save Your Life

Kidneys aren't the first pig part to enter a human body. Doctors routinely transplant pig heart valves into human patients.

-  KIMBERLY HICKOK

IN A GROUNDBREAKING 2021 EXPERIMENT, surgeons from NYU's Langone Health connected a genetically modified pig kidney to the blood vessels of a brain-dead organ donor on life support. The pig's organ filtered waste from the woman's blood and produced urine, just like a human kidney, for the entire 54-hour experiment. This first-of-its-kind procedure could signify pig kidneys as a transplant option for more than 90,000 Americans waiting for such an operation.

Transplanting organs is difficult, because our immune system is programmed to destroy anything it doesn't recognize as native to the body. Animal-to-human transplants are extra challenging because most mammals, including pigs, carry a gene that allows their body to make a sugar found in cell membranes called alpha-gal. But that gene is inactivated in some species of primates, including humans. Our immune system therefore sees alpha-gal as an intruder and produces natural antibodies designed to destroy it. In some people, alpha-gal antibodies cause an allergic reaction after they consume meat and/or dairy products (see sidebar). For transplant patients, the presence of alpha-gal in a transplanted organ can trigger an immune system response that leads to organ failure.