Augmentation cystoplasty using hydroxapatite/chitosan composite sheet seeded with autologous muscle-derived stem cells

Purpose: This study was designed to investigate the feasibility of a hydroxyapatite/chitosan (HAp/chitosan) composite, seeded with autologous muscle-derived stem cells, as a partial bladder substitute in rats. Materials and Methods: Muscle-derived stem cells were isolated from the gastrocnemius muscle of 6 female Sprague-Dawley rats, using the preplate technique, and cultured on HAp/chitosan composite sheets. Sheets with 10mm diameters were implanted into the urinary bladder of rats following a hemicystectomy in an autologous fashion. Three rats were sacrificed 4 and 8 weeks postoperatively, and the morphological changes subsequently assessed by H&E and immunofluorescence staining using DAPI, myogenin and α-smooth muscle actin (SMA). Results: All rats survived the scheduled duration. Adequate epithelialization was observed to be completed after postoperative week 4. Abundant muscle bundles, showing positive α-SMA staining, were observed after the 4th week. The bladder shape was well preserved after the 8th week. Ingrowing smooth muscles were observed on the periphery of the composite and muscular bundles, with positive myogenin immunostaining in the middle of the composite. Conclusions: A HAp/chitosan composite sheet, seeded with autologous muscle-derived stem cells, showed a degree of skeletal muscle differentiation 8 weeks after augmentation cystoplasty, in an autologous fashion. This new material seeded with muscle-derived stem cells may, in the future, prove to be a viable option as a partial bladder substitute.