An organ transplant without rejection?
In springtime, like many 16-year-olds, Kaitlyne McNamara was planning for her junior prom with excitement. And while it’s always a special occasion, this prom had particular significance for Kaitlyne and her family because of a pioneering procedure she’d had five years before.
When she was just 11, Kaitlyne received a laboratory-grown bladder, making her and six other Boston Children's Hospital patients the first people in the world to receive laboratory-grown organs.
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.
Typically, surgeons use tissue from the intestine or stomach to repair a 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.
Children’s urologist, Stuart Bauer, MD, conceived of trying a novel procedure: augmenting a spina bifida patient’s bladder with a bladder grown from her own cells. Bauer and the patient’s family met with Anthony Atala, MD, then-director of Tissue Engineering for the Urology Program at Children's, and Alan Retik, MD, urologist-in-chief. 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 surgically sutured to the patient’s original bladder. 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.
Cells are placed on a biodegradable bladder scaffold in the lab.
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 was the first time a complex organ has been constructed using autologous tissues," said Retik. "It's likely that similar organs can be constructed as well."
As for Kaitlyne, who waited until just a few days before the prom to show her father her formal champagne-colored prom dress, she now feels more fully engaged in her life. "I’m free to do basically whatever I want, and I don't have to wear diapers," she says.
Kaitlyne's success has made news around the world and has given hope to many. Children's became one of four sites to launch a larger clinical trial of how well organs work when they’ve been grown from a person's own tissue. Patients who have a medical necessity for bladder augmentation, such as those with severe spina bifida, will be the beneficiaries of this research.
From Children’s News, May 2006.
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