It's uncomfortable, embarrassing, and nobody wants to talk about it. It affects some 10 million Americans and may cost our health care system up to $1 billion a year.
It's loss of bladder control - urinary incontinence - and for at least some of the folks who have it, there's a new ray of hope.
For less than the cost of a year's supply of adult diapers, Dr. Anthony Atala may be able to make incontinence a thing of the past. The Harvard Medical School surgeon and urologist has pioneered a technique that can end leaks by using a patient's ear tissue. Clinical trials are set to start in June, and the treatment could be common in as little as a year, Atala says.
First, the doctor examines the patient to determine whether the treatment is appropriate. Roughly half of all incontinence cases result from loosening of the urinary sphincter, the bladder muscle controlling passage of urine. "It's especially common in women," Atala says. If a loose sphincter is causing patient's incontinence, he or she is a candidate for Atala's treatment.
Then he takes a small sample of the patient's ear cartilage. "It's like getting an ear pierced," says Atala.
In the laboratory, technicians break the sample up into individual cells, put them in chambers where temperature and other conditions are as close to the human body as possible, and let them grow. In only 30 days, a thumbnail-sized sample can multiply into enough cells to cover two football fields.
The patient's living cartilage cells are mixed with a fluid containing a mixture of sugars found in all human tissue. Less than a tenth of an ounce of fluid and cells gets injected into the tissue outside the bladder, right next to the sphincter. After it's injected, the fluid sets like very tough gelatin. When it gels up, it pushes the wall of the bladder next to it closer to the opposite wall, resulting in a smaller opening.
But that's just the beginning.
The cartilage cells in the mixture can still grow, using the sugars for food. They form firm but flexible tissue that holds the sphincter in its new position.
The idea of narrowing the sphincter by injecting or implanting material to push its walls closer together isn't new. Collagen has been used in that capacity for years, says Dr. Arthur Burnett, a faculty urologist at Johns Hopkins University in Baltimore.
Using a patient's own tissue for this has also been done, according to incontinence specialist Dr. Shlomo Raz, professor of urology at UCLA. "They've taken fat from a patient's abdomen and implanted it in his own urethra. It didn't work very well," he says. "But (Atala's) technique is promising and should last much longer. It's exciting work."
What's new is using tissue engineering - the idea of isolating human tissue, growing it up outside the body, and reimplanting it. It's not limited to incontinence or urology, either. Tissue engineers use or plan to use such techniques to treat conditions ranging from diabetic skin ulcers to recurrent brain cancers.
One of the concerns about using living cells in places far removed from their normal locations in the body is the lack of usual signals telling them when to stop multiplying; it doesn't do a patient much good to cure her incontinence with a cancer caused by such runaway multiplication.
Atala has solved this problem. When the cartilage cells use up all the sugars in the gel, they stop growing and start using food brought to them by local blood vessels. Within six months after injection, the sphincter is narrowed permanently and the gel has disappeared.
"The actual procedure takes 15, maybe 20 minutes," says Atala. "It can be performed in the doctor's office and the patient can go right home."
His research team is recruiting patients for the first phase of clinical trials right now, Atala says. Since this treatment doesn't use any foreign material that could cause immune rejection, Atala says he doesn't anticipate any side effects.
Aside from the embarrassment it can cause for the patient and for friends and family, incontinence can also lead to other health problems.
"When patients are wet, they're more likely to get urinary tract infections, because the way to the bladder is open more of the time," says Atala.
Serious urinary tract infections can lead to kidney failure, of particular risk to people with paraplegia, quadriplegia, or any other disease that destroys the nerves connecting the spinal cord and the bladder. Incontinent patients may also suffer skin irritation that can lead to infection.