Leonardo V. Riella, MD, PhD, is the Harold and Ellen Danser Endowed Chair in Transplant Surgery at Harvard Medical School and the Medical Director of Kidney Transplantation at the Massachusetts General Hospital. Dr. Riella’s research is focused on understanding the mechanisms of immune regulation and on developing novel therapies to promote immune tolerance. In March 2024, Dr. Riella led the world’s first successful kidney xenotransplant from a gene-edited pig into a living human patient with end-stage kidney disease. Building on this milestone, he now leads an FDA-approved pilot clinical study in xenotransplantation. Concurrently, his lab is advancing kidney bioengineering from human stem cells to create vascularized nephron units, offering a complementary path toward expanding the donor pool and transforming transplant care.