IMPLANTATION OF CULTURED UROTHELIAL CELLS INTO THE PERITONEAL CAVITY: ADVANTAGE OF FEEDER LAYER METHOD FOR SEEDING CELLS ONTO SCAFFOLD

AIM: The purpose of this study was to establish the culture method of seeding urothelial cells onto scaffold for implantation. METHODS: In vitro study: Cultured porcine bladder urothelial cells were seeded on collagen gel containing cultured porcine bladder fibroblasts (A1), on gel with no fibroblasts (B1) and on gel with feeder layer (C1) on microporous membrane. The macroscopic and microscopic appearances of the gels with urothelial cells were examined. In vivo study: Urothelial cells were cultured on collagen gel/collagen sponge matrix (CCM) containing cultured fibroblasts (A2), with no fibroblasts in CCM (B2) and with feeder layer method on CCM (C2). The survival of urothelial cells on each matrix was evaluated 28 days after implantation onto the omentum and mesenterium of nude rats. RESULTS: In vitro study: The collagen gel was shrunk in A1 but not in B1 and C1. Urothelial cells were stratified only in A1 and basement membrane formation were observed in A1 and C1. In vivo study: The urothelial cells survived on all matrices (6/6) in C2 compared to 25% (2/8) in A2 and 42% (5/12) in B2 (p<0.05). All of implanted matrices in C2 formed a cystic lumen covered with a urothelial cell lining which was stratified in 2–3 layers. CONCLUSIONS: The urothelial cells cultured with feeder layer on CCM can better survive and form a hollow-organ like lumen when implanted into peritoneal cavity. These results suggest that the selection of less degradable matrix and formation of basement membrane are critical for urothelial cell implantation.