Scaffold seeded with cells is essential in urothelium regeneration and tissue remodeling in vivo after bladder augmentation using in vitro engineered graft

Objective. Tissue-engineering methods using synthetic biodegradable scaffolds seeded with cells have potential to induce regeneration to a functional bladder wall. The aim of the study was to induce in vivo urothelial growth on implanted scaffolds previously seeded with stromal cells as compared with matrices implanted without cells for rat cystoplasty augmentation. Materials and methods. 3T3 mouse fibroblasts were multiplied up to total of 10(8) cells. Cells were grown on Dulbecco's modified essential medium supplemented with 10% of fetal bovine serum and antibiotics in CO2 chambers. Cells were seeded on biodegradable polyglycolic acid (PGA) scaffolds in eight rats: four bladders were augmented with cell-seeded grafts and the other four with acellular scaffolds. Rats were sacrificed after 4 months in preparation for hematoxylin and eosin staining. Results. One death in the acellular cystoplasty group was observed after 3 weeks. No epithelial layer was observed in the central part of the acellular graft. The cell-seeded grafts showed good visible multilayered epithelium with at least five layers of epithelial cells in the central part. The epithelium resembled rat native urothelium. The cell-seeded grafts showed a high degree of implanted 3T3 cells infiltration with good degradation of PGA fibers. Conclusions. Our data indicated that urothelial proliferation on PGA grafts was intensified using a feeder layer of fibroblasts.