Doctors have successfully implanted new bladders grown from a patient's own cells into seven children and teenagers with congenital bladder disease. The lab-grown bladders are the first tissue-engineered internal organ to work effectively in humans, and they represent an important step toward better treatments for several disabling bladder disorders.
When our bladder works right, it expands like a balloon and, when full, signals the brain that we need to urinate. But in some patients with severe bladder disease, the bladder doesn't stretch enough or the brain doesn't get the signal. This causes incontinence, bladder stones, and high-pressure urine backups that can damage kidneys.
For more than a century, urologists have surgically fashioned substitute bladders for these patients from pieces of their intestines, which are stretchy and can form a sack. But they're a poor substitute because they secrete mucus that can block urination; they also reabsorb waste that can cause urinary stones, bone problems, and cancer. So over the years doctors have tried many other replacement tissues and synthetic materials, but none worked well.
Anthony Atala, a urologist at Wake Forest University School of Medicine in Winston-Salem, North Carolina, and his colleagues have developed a new approach. They took a dime-sized biopsy of bladder tissue, which has smooth-muscle cells on the outside and specialized bladder-lining cells on the inside. Then they grew both types of cells in culture and layered them onto a bladder-shaped, biodegradable scaffold. After further nurturing, the bladders were surgically implanted into children whose spina bifida had damaged the neural connections that help signal a full bladder.
The lab-grown bladders worked adequately in the first three patients, reducing incontinence and lowering pressure slightly. But adequate wasn't good enough, so surgeons covered the implanted bladder with a nourishing tissue called omenta that improved the bladder's blood supply. In the three patients with those bladders, bladder pressure was halved, bladders held more urine, and incontinence was dramatically reduced, the researchers report today in The Lancet. Next year, Atala's team plans to try the lab-grown bladders in adults with bladder problems from spinal-cord injuries. Later, they'll use them to treat bladder cancer, Atala says.
"It's fantastic work," says Steve Chung, a urologist at the Advanced Urology Institute of Illinois in Spring Valley. For now, he cautions, the lab-grown bladders are proven only for patients with spina bifida-induced bladder damage, a relatively small group, "but I think in the very near future, we can use it for other bladder diseases."