Regenerative medicine provides alternative strategies for the treatment of anal incontinence

Anal incontinence is a common disorder but current treatment modalities are not ideal and the development of new treatments is needed. The aim of this review was to identify the existing knowledge of regenerative medicine strategies in the form of cellular therapies or bioengineering as a treatment for anal incontinence caused by anal sphincter defects. PubMed was searched for preclinical and clinical studies in English published from January 2005 to January 2016. Animal studies have demonstrated that cellular therapy in the form of local injections of culture-expanded skeletal myogenic cells stimulates repair of both acute and 2 - 4-week-old anal sphincter injuries. The results from a small clinical trial with ten patients and a case report support the preclinical findings. Animal studies have also demonstrated that local injections of mesenchymal stem cells stimulate repair of sphincter injuries, and a complex bioengineering strategy for creation and implantation of an intrinsically innervated internal anal sphincter construct has been successfully developed in a series of animal studies. Cellular therapies with myogenic cells and mesenchymal stem cells and the use of bioengineering technology to create an anal sphincter are new potential strategies to treat anal incontinence caused by anal sphincter defects, but the clinical evidence is extremely limited. The use of culture-expanded autologous skeletal myogenic cells has been most intensively investigated and several clinical trials were ongoing at the time of this report. The cost-effectiveness of such a therapy is an issue and muscle fragmentation is suggested as a simple alternative.