title: Modeling of hyperoxaluric calcium oxalate nephrolithiasis: experimental induction of hyperoxaluria by hydroxy-L-proline.
abstract: A number of animal models have been developed to investigate calcium oxalate (CaOx) nephrolithiasis. Ethylene glycol (EG)-induced hyperoxaluria in rats is most common, but is criticized because EG and some of its metabolites are nephrotoxic and EG causes metabolic acidosis. Both oxalate (Ox) and CaOx crystals are also injurious to renal epithelial cells. Thus, it is difficult to distinguish the effects of EG and its metabolites from those induced by Ox and CaOx crystals. This study was performed to investigate hydroxy-L-proline (HLP), a common ingredient of many diets, as a hyperoxaluria-inducing agent. In rats, HLP has been shown to induce CaOx nephrolithiasis in only hypercalciuric conditions. Five percent HLP mixed with chow was given to male Sprague-Dawley rats for 63 days, resulting in hyperoxaluria, CaOx crystalluria, and nephrolithiasis. Crystal deposits were surrounded by ED-1-positive inflammatory cells. Cell injury and death was followed by regeneration, as suggested by an increase in proliferating cell nuclear antigen-positive cells. Both osteopontin (OPN) and CD44 were upregulated. Staining for CD44 and OPN was intense in cells lining the tubules that contained crystals. Along with a rise in urinary Ox and lactate dehydrogenase, there were significant increases in 8-isoprostane and hydrogen peroxide excretion, indicating that the oxidative stress induced cell injury. Thus, HLP-induced hyperoxaluria alone can induce CaOx nephrolithiasis in rats.
authors.affiliation: Department of Pathology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, Florida 32610-0275, USA. khan@pathology.ufl.edu
authors.forename: S R
authors.initials: SR
authors.lastname: Khan
authors.forename: P A
authors.initials: PA
authors.lastname: Glenton
authors.forename: K J
authors.initials: KJ
authors.lastname: Byer
mesh_terms: D000818:Animals; D002118:Calcium / Q000652:urine; D002129:Calcium Oxalate / Q000378:metabolism*; D003404:Creatinine / Q000652:urine; D015237:Dinoprost / Q000031:analogs & derivatives / Q000652:urine; D004195:Disease Models, Animal; D005786:Gene Expression Regulation; D018960:Hyaluronan Receptors / Q000235:genetics / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000652:urine; D006909:Hydroxyproline / Q000009:adverse effects*; D006959:Hyperoxaluria / Q000139:chemically induced* / Q000378:metabolism / Q000473:pathology; D007150:Immunohistochemistry; D007669:Kidney Calculi / Q000139:chemically induced* / Q000378:metabolism / Q000473:pathology; D007684:Kidney Tubules / Q000378:metabolism / Q000473:pathology; D007770:L-Lactate Dehydrogenase / Q000652:urine; D008297:Male; D053495:Osteopontin; D010070:Oxalates / Q000652:urine; D051381:Rats; D017207:Rats, Sprague-Dawley; D012795:Sialoglycoproteins / Q000235:genetics / Q000378:metabolism
chemical_list: D018960:Hyaluronan Receptors; D010070:Oxalates; D012795:Sialoglycoproteins; C506897:Spp1 protein, rat; D053495:Osteopontin; D002129:Calcium Oxalate; C075750:8-epi-prostaglandin F2alpha; D003404:Creatinine; D015237:Dinoprost; D006861:Hydrogen Peroxide; D007770:L-Lactate Dehydrogenase; D006909:Hydroxyproline; D002118:Calcium