Macroscopic and HE evaluation. a. The SIS patch (1.0 × 2.0 cm) was already grafted onto the host bladder. b. Regenerated tissue in the arrows 24 weeks post-operation. c. Thin arrow marked the regenerated transitional epithelium in the region of the SIS graft. Coarse arrow marked the infiltrated inflammatory cells (×20). d. Thin arrow marked the regenerated transitional epithelium. Coarse arrow marked the new vessels (×10).