Stem cells continue to show promise in treating SUI

Advances in stem cell therapy trials and minimally invasive surgical procedures are key trends in urinary incontinence that are likely to emerge at this month's AUA annual meeting. In both human and animal trials, skeletal muscle cells show significant promise as an eventual replacement for surgery in treating stress incontinence, said Shlomo Raz, MD, director of female urology, urodynamics, and reconstructive surgery at the UCLA Medical Center.

Although he anticipated few surprises in the area of overactive bladder at the meeting, Dr. Raz said that the management of stress incontinence using stem cells is progressing on multiple fronts. He predicted a rash of posters and oral presentations showing substantive results in both animal and human trials.

In what may be the most advanced human trial to date, a European team used a two-injection protocol with stem cells derived from skeletal muscle taken from the forearm by biopsy and grown out in vitro. The researchers used a transurethral ultrasound probe to guide a myograft injection into the external sphincter of the urethra. Each patient also received a second injection of fibroblasts plus collagen into the inner portion of the urethra. Of 130 patients with stress incontinence who were treated, more than 80% were cured, Dr. Raz said.

"They [the stem cells] have possibly regenerated the urethral wall, in particular, the rabdosphincter (the skeletal musculature) in the urethral wall, creating better urethral coaptation and continence as a result. We don't know how much of the effect is the collagen against the effect of the stem cells. But it is a major step forward to future treatment."

"They create a composite of a delayed absorbable material as a foundation and add stem cells derived from fatty tissue in the surface," Dr. Raz said. "After partial cystectomy, the bladder is regenerated with increase in bladder capacity and improved compliance."

Dr. Raz cautioned that the stem cell reports are not uniformly positive. At least one group of researchers tried injecting stem cells derived from skeletal muscle into the interior of the urethra. Initial results in a small group of patients are not strongly supportive of the approach.

"If we are able to regenerate tissue and function, this is going to be a fantastic development," Dr. Raz said. "In not very many years, we will inject stem cells to treat incontinence instead of using surgery."

That is good news to the small subset of patients who suffer complications involving slings and other implanted devices. A number of papers and posters are likely to show that while the rate of complications from sling procedures is relatively low, it is also significantly under-reported. Comparisons between reports of complications associated with slings and the manufacturer and user facility device evaluation (MAUDE) database maintained by the FDA are beginning to emerge. At least one study shows many more voluntary reports of surgical complications to MAUDE than are reflected in published medical literature.

Neural stimulation advances

Neural stimulation for the treatment of refractory urgency incontinence is another area of intense interest. Although a long-standing treatment approach has been electrical stimulation of the sacral nerve, AUA attendees will see at least two papers showing positive early results of studies using electrical stimulation of the pudendal nerve. It is too early to predict when, or if, pudendal neural stimulation might move into clinical practice, Dr. Raz said.