A Transplant to Repair Urinary Incontinence?
June 4, 2001 (Anaheim, Calif.) -- Loss of urinary control is an embarrassing -- and very common -- problem that afflicts up to 17 million American adults.
Those millions will no doubt be cheering the study findings of group of Pittsburgh scientists, who have come up with a remarkable and perhaps permanent treatment that uses stem cells taken from the arm to rebuild weakened sphincters -- the muscle that controls the flow of urine from the bladder.
Stem cells are the body's primitive "starter" cells and have the capacity to grow into new tissue anywhere in the body. Almost daily, it seems, scientists are announcing new uses for these chameleon-like cells.
"What we have done is to isolate a [primitive] stem cell from a muscle in rats and mice," said Michael Chancellor, MD, who presented the research here today at the annual meeting of the American Urological Association. "Then we implant the stem cell into [the] damaged bladder and sphincter muscle in the animals. We can restore 80% of the function of the bladder and sphincter, basically rebuilding the urinary tract."
In the future, says Chancellor, who is a professor of urology and gynecology at the University of Pittsburgh School of Medicine, a woman will come into the doctor's office and a small sample of muscle tissue will be taken from her arm. "Then we will isolate stem cells from the muscle and expand them in the laboratory into a million cells," he says. "When the woman returns to the office, we will inject the stem cells and rebuild her urinary sphincter when she is leaking."
The procedure could hold the promise for a permanent solution to the problem of urinary incontinence, Chancellor says, which is due to a weakened sphincter muscle in about half of all cases. The condition causes people to urinate frequently, whenever there is even relatively minor stress on the bladder, he says.
Current therapies for urinary incontinence in women include the use of slings and screws to support the bladder and minimize leak of urine. Another treatment is the injection of collagen -- a naturally occurring fiber -- to rebuild the sphincter.
But Chancellor notes that collagen injections require multiple treatments. By injecting stem cells into the weakened sphincter once, and allowing them to grow into a new, stronger muscle, it would eliminate the need for further treatment, he says.
Using stem cells from muscle cells, rather than fetal cells, also means they cannot grow into any kind of tissue at all but can only form muscle tissue.
"If you get stem cells from an embryonic source, they can turn into something you don't want," Chancellor says. "We are taking a stem cell that doesn't have the property to generate an eyeball or a brain. It can only turn into muscle."
Chancellor and colleagues used rats and mice in their experiments, but he believes they are ready to do the experiment on humans. However, because of the many unknowns about stem cell research, academic centers have been reluctant to finance expensive human trials, he says.
Consequently, Chancellor and colleagues are hoping to find a biotechnology firm that will invest in the procedure. "We want to proceed and we are ready," he says. "We don't perceive the need to do any more animal studies."
And Chancellor believes the market for stem cell transplants to rebuild the urinary tract system may be huge.
"This is the biggest growth area in all of urology," he says. "Urinary incontinence is the last condition to come out of the closet. Only 20% of men and women ever tell their doctor about a bladder control problem."