May 2006
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An organ transplant without rejection?
Kaitlyne McNamara This spring, like many 16-year-olds, Kaitlyne McNamara is planning for her junior prom with excitement. And while it's a special occasion, this prom has particular significance for Kaitlyne and her family because of a pioneering procedure she had five years ago.
In 2001, when she was just 11, Kaitlyne received a laboratory-grown bladder, making her and six other Children's Hospital Boston patients the first people in the world to receive laboratory-grown organs. Their cases are reported in the April 4 online edition of The Lancet.
Kaitlyne was born with spina bifida, a congenital birth defect that causes incomplete closure of the spine and sometimes results in poor bladder function. Because her bladder was stiff and did not stretch as it filled, urine would seep out or sometimes back up, putting her kidneys at risk of permanent damage. She wore diapers but still worried about accidents.
Currently, surgeons use tissue from the intestine or stomach to repair the bladder, but because the intestine is designed to absorb nutrients, and the bladder is designed to excrete, patients are prone to complications, such as osteoporosis, stone formation and occasionally cancer. Kaitlyne and her parents were debating whether to try one of these surgical treatments when her Children's Hospital Boston urologist, Stuart Bauer, MD, proposed trying a novel procedure: augmenting Kaitlyne's bladder with a bladder grown from her own cells.
Cells are placed on a biodegradable bladder scaffold in the lab. Kaitlyne's mother, Tracy, was intrigued by the opportunity, and Kaitlyne thought it was, "really cool that they can actually grow a bladder in a lab."
They met with Anthony Atala, MD, then-director of Tissue Engineering for the Urology Program at Children's, and Alan Retik, MD, urologist-in-chief and senior author of the Lancet study. Retik performed a bladder biopsy, taking samples of the outer muscle cells and the urothelial cells that line the bladder walls. The cells were grown in culture in the laboratory until there were enough to place onto a specially constructed biodegradable mold, or scaffold, shaped like a bladder.
The cells continued to grow, and about seven weeks after the biopsy, the engineered bladder was sutured to Kaitlyne's original bladder during surgery. While the tissue healed, she used a catheter to empty her bladder. At her first urodynamics test, less than six months after surgery, Kaitlyne's bladder showed reduced pressures and was able to hold more than it ever had.
Today, Kaitlyne's bladder functions as well as those fashioned from intestine, but without the negative side effects. And because the organ was grown from her own cells, the risk of rejection was eliminated.
"This is the first time a complex organ has been constructed using autologous tissues," says Retik. "It's likely that similar organs can be constructed as well."
As for Kaitlyne, who is waiting until just a few days before prom to show her father her formal champagne-colored prom dress, she now feels more fully engaged in her life. "I am free to do basically whatever I want, and I don't have to wear diapers," she says.
Since the transplant surgery, "Kaitlyne is much more self confident," adds Tracy. "Five years ago, she never would have thought about wearing a dress that's so tapered to her body."
Kaitlyne's success has made news around the world and has given hope to many. "It's given a freedom that we never thought we'd see for her," says Tracy. "And more recently, shown us how mature a daughter we have. We are so proud."
This fall Children's will be one of four sites to launch a larger clinical trial of how well organs grown from a person's own tissue work. Patients who have a medical necessity for bladder augmentation, such as those with severe spina bifida, will be the most likely candidates for enrollment.
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