GUIDING SPONTANEOUS TISSUE REGENERATION FOR URETHRAL RECONSTRUCTION -LONG-TERM STUDIES IN THE RABBIT

We designed long-term in vivo experiments to study rabbit urethral reg eneration and remodelling over a hyaluronan biodegradable prosthesis. Seven months after the resection of a 1.5-cm-long tract of the urethra and its substitution with the prosthesis, radiological analysis showe d the disappearance of the implant and the re-establishment of urethra l continuity along the transmural defect. The regenerated tissue remod elled around the implant and exhibited good distensibility under press ure. Histological evaluation showed that the neo-urethra was lined wit h transitional epithelium and the stroma contained abundant elastic fi bres. An examination of the pattern of the major cytoskeletal and cyto contractile proteins of smooth muscle cells and fibroblasts was able t o distinguish fibroblasts from smooth muscle cells and myofibroblasts in the neo-urethra. These experiments provide evidence for the potenti al, successful use of biocompatible/bioresorbable devices for reconstr uctive surgery of the urethra.