EXPERIMENTAL ASSESSMENT OF SMALL-INTESTINAL SUBMUCOSA AS A BLADDER WALL SUBSTITUTE

Objectives. This study determined the feasibility of promoting urinary bladder regeneration with porcine-derived small intestinal submucosa (SIS). Methods. Twenty-two Sprague-Dawley rats underwent partial cyste ctomy with immediate bladder augmentation with SIS. Bladders were harv ested for histologic evaluation at 2, 4, 8, 12, 24, and 48 weeks. Resu lts. Histologically at 2 weeks, there was infiltration of the graft ma terial with viable host cells consisting of fibroblasts, macrophages, and blood vessels covered by complete mucosal urothelium comprised of transitional cells. During the next 10 weeks, collagen formation and m aturation were noted, and by the end of 12 weeks, the SIS graft was co mprised of a mature collagen matrix admired with thinly scattered diso rganized smooth muscle bundles and covered by normal urothelium. At 48 weeks, all three layers of the normal bladder (urothelium, smooth mus cle, and serosa) were present and were grossly and microscopically ind istinguishable from the normal rat urinary bladder. Conclusions. This study further supports the concept of bladder regeneration and suggest s that SIS may be a viable material for bladder augmentations. UROLOGY (R).