Tissue-Engineered External Anal Sphincter Using Autologous Myogenic Satellite Cells and Extracellular Matrix: Functional and Histological Studies
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The aim of the present study was to demonstrate the regaining histological characteristics of bioengineered external anal sphincters (EAS) in rabbit fecal incontinence model. The EAS of 16 rabbits were resected and decellularized. The decellularized scaffolds were transplanted to the terminal rectum following a period of 6 months of fecal incontinency (5 days after sterilization). The rabbits were divided into two groups: in group 1 (n = 8), myogenic satellite cells were injected into the transplanted sphincters. In group 2 (n = 8), the transplanted scaffolds remained in situ without cellular injection. The histological evaluation was performed with desmin, myosin, smooth muscle actin, CD31, and CD34 at 3-month intervals. The rabbits were followed for 2 years. Electromyography (EMG) with needle and electrical stimulation, pudendal and muscle electrical stimulation were also performed after 2 years of transplantation. At the time of biopsy, no evidence of inflammation or rejection was observed and the transplanted EAS appeared histologically and anatomically normal. The immunohistochemistry staining validated that the histological features of EAS was more satisfactory in group 1 in short-term follow-up. However, no statistically significant difference was detected between two groups in long-term follow-ups (p value > 0.05). In both groups, grafted EAS contracted in response to electrical signals delivered to the muscle and the pudendal nerve. However, more signals were detected in group 1 in EMG evaluation. In conclusion, bioengineered EAS with myogenic satellite cells can gain more satisfactory histological outcomes in short-term follow-ups with better muscle electrical stimulation outcomes.
KeywordsExternal anal sphincter Fecal incontinence Decellularization Myogenic satellite cells Immunohistochemistry Bioengineering
Decellularized external anal sphincter matrix
External anal sphincters
Extra cellular matrix
This study was co-founded by Tehran University of Medical Sciences. We are also highly grateful from Mrs. Safieh Lotfi for her precise editing of the manuscript.
Conflict of interest
None of the authors has direct or indirect commercial financial incentive associating with publishing the article and does not have any conflict of interest, and all have signed the Disclosure Form.
Video 7: Pudendal nerve stimulation with electrical nerve stimulator in group 1 after 2 years of implantation (MPG 3309 kb)
Video 8: Pudendal nerve stimulation with electrical nerve stimulator in group 2, two years post operatively (MPG 3951 kb)
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