One more adult stem cell therapy (and another hero)

Patients’ own stem cells are being used, every day, to treat more and more diseases. The July 11th New York Times reports on one of the heroes in the effort to treat patients using their own stem cells. Urologist Dr. Anthony Atala is pursuing research in ethical regenerative medicine at Wake Forest in North Carolina, including the use of urinary bladder stem cells to grow new bladders for children.

By 1999, he was ready to report that his bladders had functioned in dogs for a full year. That same year he inserted his bladder scaffolds into the first of seven children with spina bifida. The outcome was reported in Lancet.

All seven continue to do well, Dr. Atala said. The oldest of the new bladders has functioned for more than six years.

Working from the knowledge he had gained from bladder tissue, Dr. Atala continued to improve on a basic strategy: grow a tissue’s “committed” progenitor cells, attach the cells to a scaffold made of degradable polymers or natural substances, like collagen or keratin, and implant the structure. He first applied this strategy to the urinary and genital tracts, the territory he knows best.

“Then, once we finally got it, we thought, boy, let’s try some other tissue,” Dr. Atala recalled.

So far, his research team at Wake Forest can make only a few human parts, including bladders, urethras, patches of skeletal muscle, blood vessels and cartilage.

But in other animals, Dr. Atala has reported successes that include vaginal tissue, penile implants, kidney tissue that processes urine, pancreatic insulin-producing tissue and heart patches.

“The only changes each time are the type of cell and the biodegradable scaffolds,” he said.

To make a windpipe, for instance, the engineers seed a rigid scaffold with cartilage cells outside and respiratory cells inside. For an esophagus, a softer scaffold substance is used, its exterior coated with muscle cells, its interior with gastrointestinal cells.