Figure 1

Immunoperoxidase staining of ZIP8 in normal kidney and urothelium. A. Normal kidney. Staining of ZIP8 in the distal tubule (#) is stronger compared to the proximal tubules (+), whereas the staining is absent in the glomerulus (−). B and C. Serial section of the normal kidney stained for aquaporin-1 (B), a proximal tubule specific marker and calbindin (C), a distal tubule specific marker. (+) indicates proximal tubules and (#) indicates distal tubules. D-G. Staining of ZIP8 in the normal human urothelium. D. The urothelium from bladder shows weak staining of ZIP8 (+), mainly in the intermediate layers; the most superficial umbrella cells are negative for ZIP8 (arrows). Some spindled stromal cells in lamina propria are weakly positive for ZIP8 (*). E. The urothelium from renal pelvis shows moderate staining of ZIP8 in the intermediate layers (+); the staining of the most superficial umbrella cells (arrows) is much weaker than the intermediate layers. The asterisks indicate stromal tissue in lamina propria, which shows no staining of ZIP8. F. Strong staining of ZIP8 in the urothelium (+). Some scattered stromal cells in lamina propria are also positive for ZIP8 (*). G. Higher magnification of D, displaying paranuclear staining of ZIP8 in the cells of intermediate layers of urothelium (+). The umbrella cells are almost negative for ZIP8 (arrows). Asterisks mark the stromal cells in lamina propria with weak staining of ZIP8.