In one of the most significant moments in the history of xenotransplantation, Towana Looney, a 54-year-old woman from Alabama became the first human to live for 130 days with a gene-edited pig kidney. Her journey has now ended with the organ's removal, but it yet remains an essential landmark in the field of medicine, especially in the search for viable animal-to-human transplants.What Actually Happened That Led To The Xenotransplantation?Towana Looney underwent the groundbreaking surgery on November 25, 2023, at NYU Langone Health. She had been on dialysis since 2016 and was ineligible for a human kidney transplant due to her immune system being highly sensitized, meaning it would likely reject a human organ. As a result, she volunteered to participate in an experimental xenotransplant procedure using a genetically modified pig kidney.The transplant initially worked well. Looney even referred to herself as “superwoman,” noting that she felt better than she had in years. However, on April 4, 2024, after more than four months, her body began rejecting the organ, and doctors decided to remove it. She is now back on dialysis and recovering at home in Gadsden, Alabama.Why Was The Pig Kidney Removed?The decision made to remove the kidney came from the safety concerns as she developed an infection, which had been tied to her earlier dialysis treatment. It required doctors to reduce her immune-suppressing medicines. Around the same time, her immune system began reactivating, possibly triggering the rejection. Rather than risking a stronger dose of anti-rejection drugs—which could have caused further complications—her doctors chose to remove the kidney.“We did the safe thing,” said Dr. Robert Montgomery, Looney’s surgeon and a leading figure in xenotransplantation. He emphasized that Looney wasn’t worse off than she had been before the transplant and, in fact, had benefited from 130 days free of dialysis.ALSO READ: After Pig Kidney Transplants, Scientists May Have Found A Way To Transplant Pig LiversWhat Is Xenotransplantation?Xenotransplantation is the process of transplanting organs or tissues between different species—in this case, from pigs to humans. Scientists are modifying pigs so their organs resemble human ones more closely, in hopes of addressing the severe shortage of donor organs.Currently, more than 100,000 people in the U.S. are waiting for organ transplants, the majority needing kidneys. Thousands die every year waiting. If successful, pig organs could help close this gap.Looney’s case is part of a broader effort to test pig organ viability in people who are not terminally ill. Previously, four other U.S. patients had received pig organs—two hearts and two kidneys—but none of those organs lasted longer than two months, and all recipients eventually died due to pre-existing health issues.What Is Going To Happen Next?Despite the setback, researchers are hopeful. In fact, the news is that a man in New Hampshire who received a pig kidney in January is doing well. More clinical trials are also expected to begin this summer to give a better answer on where we stand with xenotransplantation. Chinese researchers have also reported success with a recent pig kidney transplant.One of the major ongoing challenges is determining the right combination of immune-suppressing drugs to prevent different types of organ rejection without increasing infection risk. As Dr. Tatsuo Kawai from Massachusetts General Hospital noted, “When we have more experience, we’ll know what kind of immunosuppression is really necessary for xenotransplant.”