Stimulating Vaginal Repair in Rats Through Skeletal Muscle-Derived Stem Cells Seeded on Small Intestinal Submucosal Scaffolds

OBJECTIVES: Grafts are used for vaginal repair after prolapse, but their use to carry stem cells to regenerate vaginal tissue has not been reported. In this study, we investigated whether 1) muscle-derived stem cells (MDSC) grown on small intestinal submucosa (SIS) generate smooth-muscle cells (SMC) in vitro and upon implantation in a rat model of vaginal defects; 2) express markers applicable to the in-vivo detection of vaginal endogenous stem cells; and 3) stimulate the repair of the vagina. METHODS: Mouse MDSC grown on monolayer, SIS, or polymeric mesh, were tested for cell differentiation by immunocytochemistry, Western blot and real-time polymerase chain reaction (PCR). Stem cell markers were screened by DNA microarrays followed by real-time PCR, immunocytochemistry, and Western blot. Rats that underwent hysterectomy and partial vaginectomy were left as such or implanted in the vagina with 4',6-Diamidino-2-Phenylindole (DAPI)-labeled MDSC on SIS, or SIS without MDSC, immunosuppressed, and killed at 2-8 weeks. Immunofluorescence, hematoxylin-eosin, and Masson trichrome were applied to tissue sections. RESULTS: Muscle-derived stem cell cultures on monolayer and on scaffolds differentiate into SMC, as shown by a-smooth muscle actin (ASMA), calponin, and smoothelin markers. Muscle-derived stem cells express embryonic stein cell markers Oct-4 and nanog. Dual DAPI/ASMA fluorescence indicated MDSC conversion to SMC. Muscle-derived stem cells/SIS stimulated vaginal tissue repair, including keratin-5 positive epithelium formation and prevented fibrosis at 4 and 8 weeks. Oct-4+ putative endogenous stem cells were identified. CONCLUSION: Muscle-derived stem cells/SIS implants stimulate vaginal tissue repair in the rat, thus autologous MDSC on scaffolds may be a promising approach for the treatment of vaginal repair. (Obstet Gynecol 2009;114:300-9)