The potential role of stem cells in the treatment of urinary incontinence.

Voiding dysfunction encompasses a wide range of urologic disorders including stress urinary incontinence and overactive bladder that have a detrimental impact on the quality of life of millions of men and women worldwide. In recent years, we have greatly expanded our understanding of the pathophysiology of these clinical conditions. However, current gold standard therapies often provide symptomatic relief without targeting the underlying etiology of disease development. Recently, the use of stem cells to halt disease progression and reverse underlying pathology has emerged as a promising method to restore normal voiding function. Stem cells are classically thought to aid in tissue repair via their ability for multilineage differentiation and self-renewal. They may also exert a therapeutic effect via the secretion of bioactive factors that direct other stem and progenitor cells to the area of injury, and that also possess antiapoptotic, antiscarring, neovascularization, and immunomodulatory properties. Local injections of mesenchymal, muscle-derived, and adipose-derived stem cells have all yielded successful outcomes in animal models of mechanical, nerve, or external urethral sphincter injury in stress urinary incontinence. Similarly, direct injection of mesenchymal and adipose-derived stem cells into the bladder in animal models of bladder overactivity have demonstrated efficacy. Early clinical trials using stem cells for the treatment of stress urinary incontinence in both male and female patients have also achieved promising functional results with minimal adverse effects. Although many challenges remain to be addressed prior to the clinical implementation of this technology, novel stem-cell-based therapies are an exciting potential therapy for voiding dysfunction.