title: Calcium oxalate crystal deposition in metabolic syndrome model rat kidneys.
abstract: OBJECTIVE
  Although an epidemiological link between the metabolic syndrome and kidney stone formation has been reported, the mechanism by which metabolic syndrome promotes kidney stone formation has yet to be elucidated. We investigated calcium oxalate (CaOx) kidney stone formation in a rat metabolic syndrome model.
  
  
  METHODS
  We induced hyperoxaluria in 8-week-old male Otsuka Long-Evans Tokushima fatty (OLETF) rats, and a control strain, Long-Evans Tokushima Otsuka (LETO) rats, by administering 1.0% ethylene glycol (EG) as their drinking water for 2 weeks. Rats were divided into four groups: LETO-C (control, n = 7); LETO-SF (stone forming, n = 8); OLETF-C (n = 7); and OLETF-SF (n = 8). Urine and blood samples were collected for biochemistry testing, and the kidneys were harvested for estimation of crystal deposition and determinations of the expression of osteopontin (OPN) and monocyte chemoattractant protein-1 (MCP-1).
  
  
  RESULTS
  Administration of EG induced hyperoxaluria to the same degree in both strains. The OLETF-SF group showed a higher grade of renal crystal deposition and significantly higher renal calcium content than the LETO-SF group. Although the OLETF-C group excreted significantly higher amounts of uric acid and more acidic urine than the LETO-C group, similar differences were not observed in rats given EG. Significant upregulation of both OPN and MCP-1 was seen in the kidneys of hyperoxaluric rats, with higher levels of expression in the OLETF-SF group than the LETO-SF group.
  
  
  CONCLUSIONS
  The present results show for the first time that OLETF rats form more renal CaOx crystal deposits compared with control rats under EG-induced hyperoxaluric conditions. The model described here should be useful for investigating the mechanisms by which the metabolic syndrome promotes CaOx kidney stone formation.
authors.affiliation: Division of Nephrology and Blood Purification Medicine Department of Urology, Wakayama Medical University, Wakayama, Japan. mokamoto@wakayama-med.ac.jp
authors.forename: Masanori
authors.initials: M
authors.lastname: Okamoto
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Kohjimoto
authors.forename: Akinori
authors.initials: A
authors.lastname: Iba
authors.forename: Fumie
authors.initials: F
authors.lastname: Saji
authors.forename: Isao
authors.initials: I
authors.lastname: Hara
authors.forename: Takashi
authors.initials: T
authors.lastname: Shigematsu
mesh_terms: D000818:Animals; D001835:Body Weight / Q000502:physiology; D002129:Calcium Oxalate / Q000737:chemistry* / Q000378:metabolism*; D018932:Chemokine CCL2 / Q000378:metabolism; D003460:Crystallization; D004195:Disease Models, Animal; D006959:Hyperoxaluria / Q000378:metabolism / Q000473:pathology; D007668:Kidney / Q000378:metabolism* / Q000473:pathology; D008297:Male; D024821:Metabolic Syndrome / Q000378:metabolism*; D053040:Nephrolithiasis / Q000378:metabolism* / Q000473:pathology; D053495:Osteopontin / Q000378:metabolism; D051381:Rats; D020334:Rats, Inbred OLETF; D020318:Rats, Long-Evans; D014556:Urine / Q000737:chemistry
chemical_list: C491766:Ccl2 protein, rat; D018932:Chemokine CCL2; C506897:Spp1 protein, rat; D053495:Osteopontin; D002129:Calcium Oxalate