**7. Conclusion**

**Figure 3. Muscle progenitor cells identification** *in vitro* **and muscle formation after transplantation** *in vivo***.** Myogenic cells isolated from the *Rectus abdominis* of patients undergoing abdominal surgery, grown in culture and characterized by FACS, immunohistochemistry *in vitro*. Tissue formation was evaluated *in vivo* by Hematoxilin and Eo‐ sin staining and immunohistochemistry. Function was assessed by electromyography. A: FACS analyses of cells in P2 expressing Pax 7, MyOD, desmin and upon differentiation induction Myosin Heavy Chain (MyHC). An IgG Isotype con‐ trol (red curve) was used to determine the background, whereas positive cells are plotted as a green curve. Immunocy‐ tochemistry of cells in culture expressing, MyOD (B), MyHC (C), desmin (D), sarcomeric α-actinin (E) (green -Phalloidin 488, blue – DAPI, red - mM anti-IgG Cy3). Muscle cells injected subcutaneously in nude-mice revealed muscle forma‐ tion *in vivo* (F, G, H) and contraction upon eletrical stimulation (I). HE stained (G) and labelled with sarcomeric α-acti‐ nin-Cy3 and PKH67 (H). Muscle function significantly improved over time (I), with contraction strength still increasing

after 4 weeks.\*p=0.015

696 Regenerative Medicine and Tissue Engineering

Regeneration of skeletal muscle for SUI is becoming a reality and the cell therapy may soon be available to patients. Tremendous progresses have been made to understand the science behind the natural process of skeletal muscle regeneration that involves primarily satellite cells and their progenitors, MPCs. In addition, these cells are now well-characterized with several markers at different stages of proliferation and differentiation. They are also interacting actively with their environment, which is composed of different types of cells. These neigh‐ boring cells have a significant influence on the environment and on stimulating the factors that trigger satellite cells renewal, proliferation and differentiation into myofibers. The process is complicated and involves cocktails of factors and cells. However, the interaction between these parameters is better-understood and applied in research and preclinical studies to ameliorate lack of early vascularization and innervation. In clinical trials, the first results are promising and many patients with SUI were treated successfully. The cell sources are important for a successful skeletal muscle cell therapy but they must be accompanied by a set of tools to ensure the safety and the quality of the process: culture medium, biomaterials, imaging for injection and follow-up. The advances have been made and the solutions are ready, even at the regulatory level. Although, there is not yet a standardized cell therapy for SUI, the solutions and the first results are encouraging. The cell therapy for SUI treatment will be certainly part of the choices that urologists will adopt very soon in hospitals.

### **Acknowledgements**

The authors would like to thank Mrs. Damina Balmer for her editorial assistance.
