Wake Forest researchers grow replacement tissue using patients' own cells
Posted March 8, 2011 9:27 a.m. EST
Winston-Salem, N.C. — In what is being labeled as a first, researchers at the Institute for Regenerative Medicine at Wake Forest University have grown replacement tissue from a patients’ own cells.
The team grew tissue to replace damaged segments in urinary tracts of five boys, and the tissue has “remained functional” over a six-year period.
The Institute at WFU’s Baptist Medical Center said the researchers are “the first in the world to use patients’ own cells” in development of what it calls “tailor-made urinary tubes.”
“These findings suggest that engineered urethras can be used successfully in patients and may be an alternative to the current treatment, which has a high failure rate,” said Dr. Anthony Atala, the director of the Wake Forest Institute for Regenerative Medicine who is a pediatric urologic surgeon. “This is an example of how the strategies of tissue engineering can be applied to multiple tissues and organs.”
The boys had been injured in accidents. They were treated in Mexico City.
"It's not so much science fiction anymore to think we can grow replacement organs," Patrick Warnke, a tissue engineering expert at Bond University in Australia, told The Associated Press.
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.
Atala 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.
Researchers at the institute are developing more than 30 replacement tissues and organs.
Nine children received replacement bladders starting in 1998.
Skin grafts are typically used to replaced defective urethras, the researchers noted.