Muscle stem cells treat urinary incontinence

Women with stress urinary incontinence (SUI) treated using muscle-derived stem cell injections to strengthen their sphincter muscles experience long-term improvements in their condition, according to a study led by researchers at the University of Pittsburgh School of Medicine and Sunnybrook Health Sciences Centre in Toronto.

The study, which followed patients for more than one year, suggests that the approach is safe, improves patients, quality of life and may be an effective treatment for SUI. The findings will be presented at the Tissue Engineering and Regenerative Medicine in Urology press briefing at the annual meeting of the American Urological Association (AUA) in San Diego, and will be published in Abstract 1331 in the AUA proceedings.

"This clinical trial is extremely encouraging, given that 13 million people in the United States, most of them women, cope with stress urinary incontinence," said Michael B. Chancellor, M.D., the study's senior author and professor of urology and gynecology at the University of Pittsburgh School of Medicine. "We're demonstrating for the first time that we may be able to offer people with SUI a long-term and minimally invasive treatment option."

"The technique to achieve optimal efficacy is evolving, but we are pleased with what this study has shown," added principal investigator Lesley Carr, M.D., urologist at Sunnybrook Health Sciences Centre and assistant professor at the University of Toronto. "We now have preliminary evidence that stem cells are safe to use and appear to improve female stress urinary incontinence."

Previous studies in animal models of SUI completed at the University of Pittsburgh School of Medicine demonstrated that injecting stem cells into the urethral muscles increases leak point pressure, leading to the restoration of the deficient muscles. The results of these studies formed the basis for the clinical trial.

In the study, Dr. Carr and colleagues took biopsies of skeletal muscle tissue from eight female patients and isolated and expanded the stem cells from the tissue in culture. In an outpatient setting, the patients then received injections of the muscle-derived stem cells into the area surrounding the urethra. Each patient received an equal dose of stem cell injections using three different injection techniques , a transurethral injection with either an 8-mm or 10-mm needle or a periurethral injection.

Five of the eight women who participated in the study reported improvement in bladder control and quality of life with no serious short- or long-term adverse effects one year after the initial treatment. These improvements were associated with both the 10-mm needle injections and the periurethral injections, which allowed the investigators to deliver the stem cells close to the damaged sphincter muscle. The 8-mm needle was not able to deliver the muscle stem cells deep enough into the tissue to reach the sphincter.

A multi-center study in Canada and a study in the United States are currently underway and will allow researchers to determine the optimal dose of muscle stem cells needed to effectively treat SUI.

Women with SUI involuntarily leak urine during activities that put pressure on the bladder, such as running, coughing, sneezing or laughing. Stress incontinence is caused by childbirth, menopause or pelvic surgery and is most often diagnosed in women during middle-age.