"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 demonstrated that injecting stem cells into the urethral muscles increases leak point pressure, leading to a restoration of the deficient muscles. The results of these studies formed the basis for the clinical trial.
"Our preliminary findings in this clinical trial are extremely encouraging, given that 13 million people, most of them women, cope with stress urinary incontinence in the United States," 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."
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. 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 seven women who participated in the study reported 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. The 8-mm needle was not able to deliver the muscle stem cells deep enough into the tissue to reach the sphincter.
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 Sciences 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. of Pittsburgh.