Injection of Stem Cells From a Woman’s Own Muscle May Be Effective Long-term Treatment for Urinary Incontinence

Women with stress urinary incontinence (SUI) who receive injections of muscle-derived stem cells to strengthen their sphincter muscles experience long-term improvements in their condition, according to a study led by researchers in Pitt’s School of Medicine and the 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.

“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, the study’s senior author and a professor of urology and gynecology in the Pitt medical school. “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.”

Previous studies in animal models of SUI at Pitt 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, scientists at the Sunnybrook Health Sciences Centre 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-millimeter or 10-millimeter needle or a periurethral injection.

Five of the eight participating women 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 multicenter study in Canada and another study in the United States are under way 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, and laughing. Stress incontinence is caused by childbirth, menopause, or pelvic surgery and is most often diagnosed in women during middle age.

Results of the Pitt-Sunnybrook Health Sciences Centre study were presented at the annual meeting of the American Urological Association last week in San Diego.