Doctors grow bladder cells and produce rebuilt organ Milestone work helps 7 patients Researchers at Children's Hospital Boston have reconstructed the defective bladders of seven young patients using the patients' own cells, marking the first time that tissue engineering has rebuilt a complex internal organ in humans, a top medical journal reported yesterday. The work is ''a really nice clinical milestone," said Dr. Robert S. Langer, a tissue-engineering pioneer at the Massachusetts Institute of Technology. Someday, scientists believe, they will be able to routinely regrow failing organs using tissue engineering, which takes the patient's cells, cultivates them to grow along a scaffold that gives them the needed form, and then re-implants them where needed. So far, researchers have focused on simpler pieces of anatomy such as skin. They have also fixed fingers using engineered bone, chest walls using engineered cartilage, and even major arteries. The bladder represents a next step: It is a relatively simple organ, often compared to a balloon, but nonetheless more complicated than these other tissues. ''In terms of actually engineering a complex construct that we engineer outside the body, and then we implant inside the body, this is really the first time we've been able to do that," said Dr. Anthony Atala of Wake Forest University in Winston-Salem, N.C., lead author of the research, which is published in today's issue of the journal Lancet. The experiments did not replace the entire bladder, he acknowledged. But if you think of the bladder as a light bulb, his team replaced a large piece of the round part of the bulb, he said, and they ultimately hope to do the whole bulb. That will involve added challenges in hooking up the new bladder to the tubes that come down from the kidney, he said. Atala, who was at Children's for years but recently moved to Wake Forest, serves on the board of directors of a company that has licensed patents based on the bladder tissue engineering, according to a financial disclosure in the Lancet. In the experiment, surgeons took out a piece of each patient's bladder much smaller than a postage stamp. The cells were grown in a nourishing culture and placed along a scaffold that was molded much like a dome, said Dr. Alan B. Retik, surgeon-in-chief at Children's. Then, the dome-shaped structure was connected to the remaining bladder, which had been cut wide open to receive it, and together, the two parts made a ball-shaped organ. The tissue engineers began with about 1 million cells taken from each patient's bladder, Atala said, and by the time they were ready to re-implant the new piece of bladder about seven weeks later, the engineered cells totaled 1.5 billion. The seven patients in the study, whose ages ranged from 4 to 19, had been born with spina bifida, a spinal cord disease that harms the bladder as well. Without treatment, they faced possible damage to their kidneys brought on by faulty bladder function. After the operation, the patients reported significant improvement. Story continued...
