|Authors||Sivalingam S, Nakada SY, Sehgal PD, Crenshaw TD, Penniston KL|
|Publish Date||2013 Sep 20|
Introduction: We previously reported hyperoxaluria and calcium oxalate calculi in adult pigs (sows) fed hydroxyproline (HP). The purpose of this study was to grossly and histopathologically characterize intra-renal effects in this model. Methods: In the swine facility at our campus, we maintained 21 gestating sows, of which 15 received daily treatment (10% HP mixed with dry feed) and 6 received no treatment (controls). Nine were sacrificed at 21 d (3 control, 6 HP). All kidneys were extracted and examined grossly and for radiographic evidence of stones (GE CT scanner, 80kV, 400MA, 1 sec rotation, 0.625mm slices). Papillary and cortical samples were processed for histologic analysis. Results: Kidneys from treated sows showed significant calculi distributed within renal papilla on CT, appeared mottled in the renal cortex and papillary areas, and had less distinct cortico-medullary borders. Tiny crystals and mucinous debris lined the papillary tips, calyces, and pelvis in kidneys from 4 of 6 treated sows, and multiple stones were noted at the papillary tips. H&E revealed crystals in collecting tubules and papillary tips in treated kidneys and none in controls. Yasue staining confirmed crystals in proximal peri-glomerular tubules of treated but not control animals. Tubular dilation, and inflammatory/fibrotic changes were identified in kidneys from treated animals; none of these changes were evident in control kidneys. Conclusions: We report renal damage as a result of dietary-induced hyperoxaluria in adult sows. Specifically, we found crystalluria in proximal peri-glomerular tubules and collecting ducts, with tubular damage at all segments.