Volume 84, Issue 4, Pages 818-825 (October 2013) Phenotypic characterization of kidney stone formers by endoscopic and histological quantification of intrarenal calcification  Michael P. Linnes, Amy E. Krambeck, Lynn Cornell, James C. Williams, Mark Korinek, Eric J. Bergstralh, Xujian Li, Andrew D. Rule, Cynthia M. McCollough, Terri J. Vrtiska, John C. Lieske  Kidney International  Volume 84, Issue 4, Pages 818-825 (October 2013) DOI: 10.1038/ki.2013.189 Copyright © 2013 International Society of Nephrology Terms and Conditions

Figure 1 Endoscopic mapping. A papillary still image from a CaOx stone former taken by video is shown (a) before processing and (b) after processing, with plaque (green) and plug (yellow) regions outlined and labeled. Kidney International 2013 84, 818-825DOI: (10.1038/ki.2013.189) Copyright © 2013 International Society of Nephrology Terms and Conditions

Figure 2 Histology of papillary biopsy. A biopsy from the same patient as in Figure 1 as shown by (a, c) hematoxylin and eosin (H&E) overview and (b, d) Yasue stain. (a, b) Subepithelial interstitial plaque (arrows) and (c, d) intratubular plugs were both observed. Kidney International 2013 84, 818-825DOI: (10.1038/ki.2013.189) Copyright © 2013 International Society of Nephrology Terms and Conditions

Figure 3 Urinary predictors of significant tubular plugging (>1%). Urinary (a) pH, (b) citrate, and (c) brushite supersaturation (SS) were all significantly correlated with the incidence of papillary plugging among all stone formers (P<0.05). Kidney International 2013 84, 818-825DOI: (10.1038/ki.2013.189) Copyright © 2013 International Society of Nephrology Terms and Conditions

Figure 4 Calcium phosphate (CaP) stone formers have the highest incidence of severe tubular plugging (>1% surface area) compared with calcium oxalate (CaOx) formers and CaOx stone formers with maladsorption. Within the CaP group, the brushite stone formers had a greater percentage with plugs than those with apatite stones. Black, plugs >1%; gray, 0<plugs <1%; white, no plugs. Kidney International 2013 84, 818-825DOI: (10.1038/ki.2013.189) Copyright © 2013 International Society of Nephrology Terms and Conditions

Figure 5. Inhibition activity (Ia) of urine relative to the presence of tubular plugs. Patients with significant plugs (>1% of the surface area) had reduced crystal growth inhibition activity both among the (a) cohort as a whole (P<0.01) or (b) the CaOx group (P<0.01). Kidney International 2013 84, 818-825DOI: (10.1038/ki.2013.189) Copyright © 2013 International Society of Nephrology Terms and Conditions

Figure 6 Correlation of endoscopic mapping and histologic staining. (a) Plaque and (b) plug amounts quantified by endoscopic video mapping using a digital nephroscope correlated significantly with histologic measurements made on a representative papillary tip biopsy (P<0.05). Kidney International 2013 84, 818-825DOI: (10.1038/ki.2013.189) Copyright © 2013 International Society of Nephrology Terms and Conditions