Ureteral replacement using collagen sponge tube grafts.

The use of a collagen sponge tube graft as a material for segmental ureteral replacement was investigated. The structural design of the collagen sponge graft was achieved by cell culture on the matrix. MGH-U1 cells, derived from bladder cell carcinoma, were grown in vitro on the collagen sponge matrix with excellent biocompatibility and without evidence of cytotoxicity. The collagen sponge demonstrated biodegradability when implanted subcutaneously in dogs. However, a urine exposure test of collagen sponge in rat bladders revealed extensive salt deposits on its surface in some rats, as observed by crystallographic examination. Segmental ureteral replacements by collagen sponge tube grafts, accompanied by ureteral splint catheters, were performed in dogs. There was extensive uro-epithelial cell regeneration on the inner surface of the collagen grafts, without evidence of severe hydronephrosis, 5 to 12 weeks following the procedure. The results indicate the potential for ureteral replacement by collagen sponge tube grafts, which would act as non-toxic, biodegradable scaffolds inducing the regenerative activity of the ureter.