In a historic leap for organ transplantation, a 41-year-old man named Oscar Larrainzar has become the first person in the world to successfully receive a human bladder transplant, marking a monumental milestone in regenerative medicine and urology.
The groundbreaking surgery took place on May 4, 2025, at the Ronald Reagan UCLA Medical Center, where a team of specialists led by Dr. Inderbir Singh Gill of the Keck School of Medicine at USC, and Dr. Nima Nassiri of UCLA, performed a combined kidney and bladder transplant.
Larrainzar, who lost both kidneys and most of his bladder to cancer, had been dependent on dialysis for seven years. The eight-hour operation began with a kidney transplant — a procedure known to many — but what followed was unprecedented: a complete bladder transplant, involving delicate reconnection of the complex web of blood vessels and urinary pathways.
“As soon as the new kidney was connected, it began producing urine that drained properly into the transplanted bladder,” said Dr. Gill. “No dialysis was needed post-operation — that’s a huge sign of success.”
This medical feat is the result of four years of intense research and surgical innovation by Gill and Nassiri. They meticulously rehearsed the procedures on deceased donors, using ventilator-supported bodies to replicate living organ conditions and refine surgical techniques, especially the challenging vascular reconnections critical to bladder survival.
Unlike previous methods for treating bladder loss — such as using a section of the intestine to create a urinary diversion — bladder transplantation offers a more anatomically and functionally accurate solution, with the potential for greater quality of life and fewer complications like infections and digestive issues.
Larrainzar is currently under close post-surgical observation to monitor for any signs of organ rejection or complications, and to assess how well his new bladder stores and voids urine naturally.
The success of this operation now sets the stage for a broader clinical trial, aiming to replicate results in more patients with terminal bladder conditions, many of whom are currently left with limited, high-risk options.
“We’re excited about the early success, but the real test will be long-term bladder function and integration,” said Gill.
Bladder cancer remains a major health burden, with an estimated 85,000 new cases and over 17,000 deaths expected in the U.S. in 2025, according to the American Cancer Society. Current treatments often involve removing the bladder, leaving patients with life-altering impacts.
A successful transplantation offers renewed hope for thousands living with bladder loss, whether due to cancer, congenital issues, or trauma. It could eventually lead to routine bladder replacement, much like kidney or liver transplants today.
Summary
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Patient: Oscar Larrainzar, 41, first to receive a human bladder transplant
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Date: May 4, 2025
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Location: Ronald Reagan UCLA Medical Center
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Surgical Team: Dr. Inderbir Gill (USC) and Dr. Nima Nassiri (UCLA)
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Outcome: Kidney began functioning immediately; bladder working; no dialysis needed
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Next Steps: Expand clinical trial, monitor long-term bladder function
This first successful bladder transplant could change the landscape of urological care and cancer recovery, marking the dawn of a new era in organ replacement therapy.
