It was literally a back-of-the-envelope idea. Dr. Nima Nassiri had pulled out an envelope to scribble notes on how a bladder transplant could be accomplished in a living person—a surgery that had yet to be performed successfully.
It was 2021, the COVID pandemic was raging, and Nassiri, then a medical resident, was brainstorming ideas with urologist Dr. Inderbir Gill in a school cafeteria.
About four years later, on May 4, 2025, Nassiri—now 37 and an assistant clinical professor of urology at the University of California, Los Angeles—and Gill performed a bladder transplant on a 41-year-old father of four. The procedure, a world first, was a tremendous success. The patient recovered well and has excellent bladder function, Nassiri says.
Nassiri now plans to perform several more bladder transplants in 2026 as part of an ongoing clinical trial. Patients who need these transplants are often people who are “out of options,” Nassiri says. “If we're able to develop something that can help them, that's huge. That's the kind of impact I always wanted to have.”