Lab made urinary tube going strong after six years of transplant

By Dr. Ananya Mandal, MDMar 8 2011

In a scientific breakthrough, five boys who were unable to urinate due to pelvic injury were cured for up to six years after getting new lab-grown urethras or urinary tubes that connect with the bladder. This breakthrough comes from Wake Forest University researcher Anthony Atala. It was in 2006 that the team reported the first successful implantation of lab-grown urinary bladders into humans. Today six years after the operation all of the boys continue to do well, with normal or near-normal urinary flow. The boy first treated is now 16 years old and received his lab-grown urethra over six years ago.

Atala and colleagues report, “Tissue-engineered urethras, repaired with patients’ own cells, can be used to successfully treat complex urethral defects,” They used urethras that were grown on biodegradable mesh scaffolds made of a polyester compound. /these scaffolds were seeded with cells taken from the boys’ own bladders and incubated in the lab for four to seven weeks. They were then used to surgically repair damaged segments of the boys’ urethras 1 1/2 inches to 2 1/2 inches in length. The boys who underwent the procedures at a hospital in Mexico City were 10 to 14 years old. They had sustained injuries that had severed their urethras, making it impossible for them to urinate properly and requiring them to use catheters.

The team waited for six years to announce the successful use of lab-grown urethras. Meanwhile they have also grown the world’s first liver grown in the lab from human cells. Work is also under way to create other lab-grown organs, including the pancreas, kidney, and even the heart. Atala said it costs about $5,000 to create a replacement urethra. He did not know the cost of the surgery but said the procedure would save money over time because these types of procedures would not need to be redone, unlike the method currently used.

Atala and colleagues report their findings in the March 8 online edition of The Lancet. It was funded by the U.S. National Institutes of Health.

There are caveats about the findings, however. The injuries sustained by the boys are rare, and the study included just five boys. The procedure needs more testing, and it is not known if it would work in adults. And, creating body parts from cells - the crux of tissue engineering’s potential - remains an immense challenge fraught with failure. But according to Dr. Karl-Dietrich Sievert, professor of urology at the University of Tuebingen in Germany who wrote a commentary accompanying the study feels, “we are definitely a step further in demonstrating that the results that have been reported in animals can be translated to clinic”.

For now, however, products of tissue engineering are rarely used in medicine outside of skin grafts, said Nenad Bursac, associate professor of biomedical engineering at Duke University. One hurdle is cost, he said. However, Bursac said, research is continuing and scientists are in the early stages of testing products for the repair of cartilage, the cornea and the heart. Atala said larger studies would be needed before the treatment could be widely used.