A simple injection of stem cells from a woman's own muscle may effectively treat urinary incontinence

TORONTO - In the first clinical study of its kind in North America, women with stress urinary incontinence (SUI) were treated using muscle-derived stem cell injections to strengthen deficient sphincter muscles responsible for the condition. Results of the study, led by researchers at Sunnybrook Health Science Centre in Toronto and the University of Pittsburgh School of Medicine, suggest that the approach is safe, improve patients' quality of life and may be an effective treatment for SUI. The findings will be presented at an experts' session at the annual meeting of the American Urological Association (AUA) in Atlanta, and will be published in abstract 1185 in the AUA proceedings.

"The technique to achieve optimal efficacy is evolving, but we are pleased with what this study has shown," said 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 at the University of Pittsburgh School of Medicine in animal models with SUI have demonstrated that injecting stem cells into the urethral muscles increases leak point pressure, leading to a restoration of the deficient muscles.

"These findings are extremely encouraging to the 13 million people, most of them women, coping with stress urinary incontinence in the United States alone," 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. "These findings suggest, for the first time, that we may be able to offer people with SUI a long-term and minimally invasive treatment."

In the study, researchers took biopsies of skeletal muscle tissue from seven female patients and isolated and expanded the stem cells from the tissue in culture. The patients then received injections of the muscle-derived stem cells into the area surrounding the urethra in an outpatient setting. 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 seven women who participated in the study reported an improvement in bladder control and quality of life with no serious short or long-term adverse effects. 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.

A follow-up multi-site study set to launch this summer will allow researchers to determine the optimal dose of muscle stem cells needed to effectively treat SUI.

Women with SUI involuntarily lose 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.

In addition to Drs. Carr and Chancellor, contributors to the study included Deborah Steele and Shannon Steele, with Sunnybrook Health Science Centre and David Wagner, Ryan Pruchnic, Ron Jankowski, Janet Erickson, Fernando de Miguel, Naoki Yoshimura and Johnny Huard, with the University of Pittsburgh School of Medicine. The study was funded by Cook MyoSite Inc. in Pittsburgh, Pa.