A New Era in Transplant Medicine: UCLA Health Performs the World’s First Bladder Transplant

It’s 2 am. Nima Nassiri, MD, has just removed a bladder from a research donor and is attempting to flush it with solution – a critical step that will determine if he is able to keep the blood supply to the organ intact. He’s been here before – but prior attempts weren’t always successful.

This time it works. Dr. Nassiri began exploring bladder transplantation during the COVID-19 pandemic. He started with pigs, progressed to cadavers and finally to human organ and tissue donors.

In May of 2025, Dr. Nassiri and Inderbir Gill, MD, performed the world’s first human bladder-kidney transplant at UCLA Health. On June 23, The Lancet published their paper detailing the “first in human feasibility trial” of bladder transplantation.

The 38-year-old surgeon and director of the UCLA Bladder Transplant Program has already done two more bladder-kidney transplants as part of an ongoing clinical trial.

“I have my trajectory forward. I see the path,” he says.

The first bladder transplant

Bladder transplants are particularly challenging because of the vascular structure of the pelvic area and the technical precision required to remove and successfully establish blood supply to the organ. In April 2024, the bladder transplant team met its first patient in a surgical evaluation clinic: Oscar Larrainzar. Dr. Nassiri was part of the surgical team that removed Larrainzar’s failed kidneys in 2020. Larrainzar also survived a rare form of bladder cancer, leaving him with a non-functional organ, and had been on dialysis for years.

Just over a year after his April 2024 visit, Larrainzar became the world’s first bladder transplant recipient.  Performing a world-first transplant required extensive planning, regulatory oversight and approvals from several review boards and committees.

“Bladder transplantation could only have happened at UCLA, because of the culture of support for innovative therapies, and because the Department of Urology has a rich history of clinical and scientific contribution to the field of kidney transplantation,” Dr. Nassiri says. He also credited OneLegacy, UCLA’s organ procurement partner.

The achievement drew national media attention, and TIME100 Health named Dr. Nassiri one of the top 100 individuals shaping the future of medicine.

For Larrainzar, 43, the operation was life-changing. His new kidney and bladder worked right away; he was able to urinate on his own for the first time in seven years.

“It has been beyond expectations,” said Larrainzar. “It’s like living … a normal life again.”

Becoming a medical innovator

Dr. Nassiri didn’t go into medicine to make history. He simply wanted to be a surgeon like his older brother.

Getting into the David Geffen School of Medicine at UCLA was a “transformational moment,” Dr. Nassiri says, exposing him to the “powerhouse that is UCLA Urology.”

During his urology rotation, Dr. Nassiri worked with Jeffrey Veale, MD, a pioneer of “tolerance” kidney transplantation, which eliminates the need for lifelong immunosuppressive medication to prevent the body from rejecting the new organ.

After graduating, he completed his residency at USC, returned to UCLA Health for a fellowship in kidney transplantation and then joined the faculty at the David Geffen School of Medicine in 2025 with early support from then-department chair Mark Litwin, MD.

“Bladder transplantation has been Dr. Nassiri’s principal focus since we recruited him to the UCLA faculty,” Dr. Litwin says.

Dr. Nassiri credits his success to the integrated team at UCLA Health.

The future of bladder transplant

With two bladder-kidney transplants scheduled to complete the clinical trial, Dr. Nassiri is looking to make the procedure more widely available.  It’s ideal for people with end-stage bladder disease who are already on, or will need, immunosuppression. Residents and fellows are learning the technique as well; one plans to bring it to his home program in Canada.

Next up is making bladder transplant available for pediatric patients.

“In children and adolescents, one of the major causes of kidney failure is bladder failure,” Dr. Nassiri says. “Absent a bladder transplant, these children undergo urinary reconstruction using bowel or intestine, which comes with its own lifelong complications.”

His dream is to combine bladder-kidney transplant with the tolerance program led by Dr. Veale, so organ recipients can live without toxic anti-rejection drugs.

“My ideal situation would be this: There’s a patient who doesn’t have functional kidneys or a functional bladder, and we give him a kidney and we give him a bladder, and we take him off immunosuppression and he lives a normal life,” Dr. Nassiri says.

Dr. Nassiri is excited about what the future holds and looks forward to taking his work to the next level with the support of UCLA Health.