Stemming Incontinence: Injected muscle cells restore urinary control

Stem cells taken from a woman’s arm and used to rebuild a pivotal control muscle in her urinary tract can relieve incontinence, medical researchers report. For women, this replenishing of muscle cells offers “a revolutionary therapy,” claims radiologist Ferdinand Frauscher of the Medical University of Innsbruck in Austria.

Typical urinary incontinence in women, called stress incontinence, results from weakness in the sphincter muscle that seals the urethra at the base of the bladder. Age, childbirth, and other factors can make sphincter contraction less effective. Treatments such as surgery and implantable devices that control urine flow can be effective, but they both require hospitalization and the devices can be cumbersome.

The Austrian team’s new technique is less likely to work in men, Frauscher says, because male incontinence often turns up after prostate surgery, and the scar tissue would be likely to prevent stem cells from rebuilding the muscle.

To repair the sphincter muscle, Frauscher and his colleagues removed tissue from the left biceps muscles of each of 20 women. The women, all of whom had urinary incontinence, ranged from 36 to 84 years old.

In the lab, the researchers extracted two types of muscle stem cells from the tissue. One type, cells that generate myoblasts, enables muscles to contract. The other type, fibroblasts, forms connective tissue.

After cultivating the stem cells for 6 weeks, Frauscher’s team had about 50 million of each type for each patient. To place the cells, they threaded an ultrasound probe up each patient’s urethra. Using ultrasound imagery to provide anatomical guidance, the team’s physicians then inserted a needle through the abdomen and injected the myoblasts into the sphincter and the fibroblasts into the urethral wall.

Many patients noticed improved urine control within a day, and 18 of the 20 had normal control a year after the operation, Frauscher and his colleagues reported last week at a meeting of the Radiological Society of North America in Chicago.

No patients needed to be hospitalized, and none experienced complications following the procedure, Frauscher says. Ultrasound tests indicated that most sphincter muscles treated in the study had thickened and now contract more effectively, he adds.

Vikram Dogra of the University Hospitals of Cleveland expressed surprise at how rapidly the stem cells reduced incontinence. He calls the recent work “a good start,” noting that long-term success “remains to be seen.”

Although the new study didn’t directly compare the stem cell procedure to conventional surgery, the preliminary evidence suggests that the two treatments are about equally effective, at least in the short term, Dogra says, and the new method would avoid a hospital stay and reduce the risk of infection.