Figure 6.

Correlation analysis between neutrophil distribution and papillary pathology. (a) Linear regression analysis was performed between neutrophil abundance in brushite (Bru) and calcium oxalate (CaOx) papilla biopsies compared with papillary endoscopic scoring of plugging (left) or Randall’s plaque (RP) (right). No correlation was observed between these events (P = 0.60 and 0.94, respectively). (b) Maximum projection of a papillary biopsy labeled with myeloperoxidase (MPO) (neutrophils) or aquaporin 1 (AQP1) (thin descending limb) shows diffuse pattern of neutrophil distribution (left). Region of interests (ROI) marking collecting ducts were manually drawn (yellow) and distance maps were built for every ROI (example of a distance map shown in the enlarged image in inset). The positions of all the neutrophils surveyed using volumetric tissue exploration and analysis were correlated to locations on the distance maps. Neutrophil distance distribution was nearly identical to a randomly generated distribution (Gaussian), shown in the histograms depicted in (c) (P = 1.0), suggesting no spatial correlation between neutrophil distribution and collecting ducts.