Stress urinary incontinence and regenerative medicine: is injecting functional cells into the urethra feasible based on current knowledge and future prospects?

Stress urinary incontinence (SUI) is one of the most prevalent disorders of the lower urinary tract. Actual standard conservative and surgical therapeutic modalities are offering a symptomatic relief without treating the underlying disorder. Therefore, advances in cell-based regenerative medicine have implemented the use of autologous cells with the aim to treat urinary incontinence. Different types of cells have been investigated to regain the function of the rhabdosphincter muscle in the urethral closure complex: myogenic progenitor cells, adipose tissue-derived stromal cells and mesenchymal stromal cells were mostly applied. Many of the preclinical studies published success of cell therapies. However, most clinical studies included only a few patients and rather short periods of follow-up. Furthermore, different cell types as well as injection techniques were used. The use of stem cells seems to be a feasible and safe technique with promising results in patients with SUI. However, as a result of heterogeneity of preclinical and clinical trials, the best approach to cell-based therapy in SUI is still under investigation. The definition of the optimal cell type applied for the regeneration of the sphincter, the development of surgical injection advices and adequate tools for the investigation of the muscle regeneration during the follow-up have to be investigated to improve the use of autologous cells in the therapy of SUI.