The first complex organ, the bladder, has been rebuilt in seven patients from living tissue cultivated in the lab.
Over the past decade, researchers began fashioning better scaffold-like platforms that hold growing cells and dissolve inside the body. The study of stem cells, which can mature into all the body's other tissues, has also supercharged progress in regenerative medicine.
The researchers at Children's Hospital in Boston used a more mature cell type known as a progenitor. They first operated on the patients to remove bad tissue that made up more than half their bladders. They fished out muscle and bladder wall cells, seeded them on cup-like bladder-shaped scaffolds of collagen, then let the cells reproduce in the lab for seven weeks. Starting with tens of thousands, they ended up with about 1.5 billion cells. The cell-bearing molds were then surgically sewn back to the remnants of the patients' original and partly working bladders, where the lab-nurtured cells kept maturing.
The team, which began its work in 1999, followed the last patient for almost two years. In undergoing the experimental procedure, the patients skirted the typical side effects of grafts that would otherwise have been made with their own intestinal tissue.
The patients in the study must still cope with the ravages of spina bifida, the birth defect that caused their bladder problems. Leaving the spine incompletely closed, spina bifida can turn off nerve signals that keep the bladder healthy. The stiff, leathery bladder leaks frequently, forcing the person to wear pads or diapers. What's worse, the weakened bladders can flush urine back into the kidneys and damage them too.
The rebuilt bladders, though, were up to three times more elastic and better at holding urine, the researchers report. In all seven patients, kidney function was preserved, the study said. The patients must still empty their bladders regularly with a tube but can avoid leaking in between.
For Kaitlyne McNamara, the urinary infections, leaking, and daily diapers are now just embarrassing memories.
A previous article from this site summarized the status of regenerative medicine