Histochemistry in vivo with (a) H&E and (b) Trichrom-Masson staining after 48 weeks (50x), Left side: tissue engineered ureter. Middle: ureter construction with unseeded scaffolds. Right side: native ureter. In the tissue engineered ureter an urothelial lining (U) is evident on top of the venous scaffold (V) (left row) while in the unseeded grafts no urothelial lining is noticeable. In the third row the typical ureteral histologic architecture with urothelium (U), submucosal layer (SM), and muscular layer (M) is recognisable. While the H&E staining reveals the general architecture, in the Trichrom-Masson staining the low content of collagen (blue color) in all tissues representing the low grade of scar tissue formation is noticeable.