Preliminary study of tissue engineered bladder regeneration with poly (ε-caprolactone) (PCL) sheet seeded with autologous muscle-derived stem cell

Purpose: To investigate the feasibility of using a poly(ε-caprolactone) (PCL) sheet seeded with autologous muscle-derived stem cells as a bladder substitute. Materials and methods: Muscle-derived stem cells were isolated from the gastrocnemius muscle of 9 female Sprague-Dawley rats using a preplate technique, and cultured on a 5×5mm PCL sheet. The sheets were implanted into the mesentery of the rats in an autologous manner. Three rats were sacrificed 2, 4 and 8 weeks after implantation, and the morphological changes were assessed by H&E and immunofluorescence staining including DAPI, myosin heavy chain (MHC) and choline acetyl transferase (CAT). Results: All the rats survived for the scheduled time. A mild inflammatory reaction was observed around the PCL sheet in the postoperative 2-week specimen but this receded with time. Muscle cells on the sheet were observed over the experimental period. The 8-week specimen showed a moderate amount of muscle cells on the sheet, and MHC and CAT immunofluorescence staining showed a positive reaction. The muscle layer was not well organized. Angiogenesis was quite noticable between the sheet and the muscle cells on the 8-week specimen. Conclusions: A PCL sheet seeded with autologous muscle-derived stem cells showed skeletal muscle differentiation on the sheets 8 weeks after mesenteric implantation in an autologous manner. This suggests the feasibility of using a PCL sheet seeded with autologous muscle-derived stem cell as a bladder substitute.