Stress urinary incontinence (SUI) is a common urogenital disease, defined as the involuntary leakage of urine in the absence of a detrusor contraction, generally due to the weakness of the urethral sphincter and pelvic floor. More than 200 million people worldwide suffered from SUI, which seriously affects the quality of life of patients. As a disease whose prevalence is related to advancing age, it affects more women than men with an approximate ratio of 3 : 1. For women, both pregnancy and vaginal birth are associated with an increased risk of the levator ani muscle defects. Pregnancy and delivery decrease the expression of hypoxia inducible factor-1 and vascular endothelial growth factor, which may inhibit the angiogenic response and tissue repair of pelvic floor after childbirth. Likewise, SUI can also affect men and is primarily caused by urethral sphincteric deficiency after radical prostatectomy. At present, several treatments for SUI are available, of which bulking agent injection and Tension-Free Vaginal Tape are the most common and effective therapeutic methods. The various injectable bulking agents applied for the treatment of SUI patients include bovine collagen, carbon beads, silicone, and polyacrylamide hydrogel. However, an ideal periurethral injectable agent for treating SUI has not been found so far. In addition, due to degradation of bulking agents, their efficacy gradually declines over a period of months or years. Surgery, including sling procedures and bladder neck suspensions, is more efficacious to control the voiding. It is previously reported that the procedures have a 5-year cure rate of more than 80%; however, this procedure has a series of side effects including urinary retention, bladder perforation and hematoma formation
One approach would be the use of stem cells. Stem cells can be easily isolated in high quality and large quantities in vitro and have the potential to develop into any cell type especially during phases of early life and growth. In some organs, stem cells constitute a repair mechanism that is able to replenish cells whenever damage or injury occurs. They are unspecialized cells characterized by a self-renewal property where each daughter cell can either remain undifferentiated or become specialized with a defined function. In addition, provided the appropriate environment and conditions, stem cells can be induced to differentiate into a specific cell-like or tissue-like phenotype with a specifically determined function. Additionally, stem cells are known to have antiapoptotic, antiscarring, and neovascularization effects. Moreover, autologous stem cell transplantation eliminates the risk of immunological rejection.
Thus, with their multidifferentiation potential, the stem cells can be induced to differentiate into myoblast to solve the problem of urethral sphincter dysfunction. Here, we summarize relevant progress of stem cell therapy research for SUI and discuss the potential challenges in this paper.