Wed, Mar 09, 2011 - Page 7 News List

US doctors claim success in creating new urethras

AP, LONDON

Doctors have created urethras using patients’ own cells for the first time — another example that scientists may be able to grow replacement body parts one day

“It’s not so much science fiction anymore to think we can grow replacement organs,” said Patrick Warnke, a tissue-engineering expert at Bond University in Australia.

US doctors made the urethras for five boys in Mexico, aged 10 to 14, after they were injured in accidents.

The urethra is a thin tube that carries urine out of the body from the bladder; cells from both organs are very similar. Tissue grafts are normally used in such cases, but there’s a less than 50 percent success rate.

After removing a postage-size piece from the boys’ bladders, scientists put the cells into a special mixture in a laboratory to speed their growth. They then fashioned a tiny mesh tube out of the same material used for dissolvable stitches in surgeries to act as a scaffold. After that, the scientists alternately coated the tube with muscle cells on the outside and lining cells on the inside.

Anthony Atala, a professor of surgical sciences at the Wake Forest University School of Medicine, described the process as “very much like baking a layer cake.”

He said the new structure is put into an incubator for several weeks before being implanted into the patient, in the knowledge that the scaffold will eventually disintegrate, leaving the boys’ own cells as a new urethra.

Up to six years after having their new urethras implanted, Atala said the boys’ organs are fully functional and no major side effects were reported.

“It’s like they now just have their own urethras,” Atala said.

He said the techniques used might be applied to create more complicated tubular structures in the body, like blood vessels.

Atala and her colleagues have previously made bladders using patients’ own cells.

The urethra research was paid for by the US National Institute of Diabetes and Digestive and Kidney Diseases and the National Institutes of Health. It was published online yesterday in the medical journal, Lancet.

In recent years, doctors have made new windpipes for patients partly from their own stem cells. Warnke’s team has grown a replacement jaw and is now working on an eye.

Warnke also thought it was possible that children — who heal faster than adults — might be better candidates for such procedures in the future, though that could raise ethical dilemmas.

“Tissue regeneration is much faster in children, but my gut feeling tells me not to do it,” he said. “If you mess it up in a child, it will be horrific.”

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