Functional outcome of the anterior vaginal wall in a pelvic surgery injury rat model after treatment with stem cell-derived progenitors of smooth muscle cells.

Background: Stem-cell-derived therapy is a promising option for tissue regeneration. Human iPSC-derived progenitors of smooth muscle cells (pSMCs) have limited proliferation and differentiation, which may minimize the risk of in vivo tumor formation while restoring smooth muscle cell deficiencies. Up to 30 % of women who suffer from recurrence of vaginal prolapse after prolapse surgery are faced with reoperation. Therefore, there is an unmet need for therapies that can restore vaginal tissue function. We hypothesize that human pSMCs can restore vaginal function in a vaginal-injury rat model.

Methods: Female immune-compromised RNU rats were divided into 5 groups: intact controls (n=12), VSHAM (surgery + saline injection, n=33), and cell-injection group (surgery + cell injection using three patient pSMCs lines, n=14/cell line). The surgery, similar to what is done in vaginal prolapse surgery, involved ovariectomy, urethrolysis, and vagina injury. The vagina, urethra, bladder dome and trigone were harvested 10 weeks after surgery (5 weeks after injection). Organ bath myography was performed to evaluate the contractile function of vagina, and smooth muscle thickness was examined by tissue immunohistochemistry. Collagen I, collagen III, and elastin mRNA and protein expressions in tissues were assessed.

Results: When compared to the VSHAM group, cell-injection groups showed significantly increased vaginal smooth muscle contractions induced by carbachol (groups A and C) and by KCl (group C), and significantly higher collagen I protein expression in the vagina (groups A and B). Elastin mRNA and protein expressions in the vagina did not correlate with injection group. In the urethra, mRNA expressions of collagen I, collagen III, and elastin were all significantly higher in the cell-injection groups compared to the VSHAM group. Collagen I protein expression of the urethra was also higher in the cell-injection group compared to the VSHAM group. Elastin protein expression in the urethra did not correlate with injection group.

Conclusions: Human iPSC-derived pSMCs improved contractile function of the post-surgery vagina. Additionally, pSMC injection modulated collagen I, collagen III and elastin mRNA and protein expressions in the vagina and urethra. These findings suggest that pSMCs may be a possible therapy for vaginal prolapse recurrence after surgical intervention.