title: Fibroblast growth factor 23 in feline chronic kidney disease.
abstract: BACKGROUND
  Fibroblast growth factor 23 (FGF-23) is a phosphaturic hormone involved in the pathogenesis of secondary renal hyperparathyroidism (SRHP) in humans. There are no published studies examining feline FGF-23.
  
  
  OBJECTIVE
  Validation of a method for FGF-23 quantification in feline plasma and assessment of the associations among plasma FGF-23, PTH, creatinine, and phosphate concentrations in cats with chronic kidney disease (CKD).
  
  
  METHODS
  One hundred nonazotemic and azotemic geriatric (>9 years) client-owned cats.
  
  
  METHODS
  Retrospective cross-sectional study: Cats were categorized into 4 groups: control group (plasma creatinine (Cr) ≤2.0 mg/dL), stage 2 (Cr 2.1-2.8 mg/dL), stage 3 (Cr 2.9-5.0 mg/dL), stage 4 (Cr >5.0 mg/dL). Stages 2 and 3 were further subdivided based on International Renal Interest Society targets for plasma phosphate concentration (PO4 ): stage 2a (PO4 ≤4.5 mg/dL), stage 2b (PO4 >4.5 mg/dL), stage 3a (PO4 ≤5 mg/dL), stage 3b (PO4 >5 mg/dL). Plasma FGF-23 concentrations were measured by a human intact FGF-23 ELISA. Descriptive statistics and linear regression were performed.
  
  
  RESULTS
  The ELISA demonstrated acceptable precision, reproducibility, and specificity. Plasma FGF-23 concentrations increased with increasing plasma creatinine concentrations and were significantly different between all groups (P < .008). Plasma FGF-23 concentrations were significantly higher in cats in stage 2b than stage 2a (P = .008) and in stage 3b than in stage 3a (P = .012). Phosphate, log creatinine, total calcium, log parathyroid hormone, and packed cell volume were all independent predictors of FGF-23.
  
  
  CONCLUSIONS
  FGF-23 concentrations increase with increasing stage of feline CKD and might be a marker or mediator of feline SRHP.
authors: Department of Veterinary Clinical Sciences, Royal Veterinary College, Hatfield, UK. rgeddes@rvc.ac.uk
authors: R F
authors: RF
authors: Geddes
authors: N C
authors: NC
authors: Finch
authors: J
authors: J
authors: Elliott
authors: H M
authors: HM
authors: Syme
mesh_terms: D000818:Animals; D002371:Cat Diseases / Q000097:blood*; D002415:Cats; D003404:Creatinine / Q000097:blood; D003430:Cross-Sectional Studies; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods / Q000662:veterinary; D005260:Female; D000089703:Fibroblast Growth Factor-23; D005346:Fibroblast Growth Factors / Q000097:blood*; D006962:Hyperparathyroidism, Secondary / Q000097:blood / Q000662:veterinary; D057230:Limit of Detection; D008297:Male; D010281:Parathyroid Hormone / Q000097:blood; D010710:Phosphates / Q000097:blood; D012016:Reference Values; D051436:Renal Insufficiency, Chronic / Q000097:blood / Q000662:veterinary*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018709:Statistics, Nonparametric
chemical_list: C000717427:FGF23 protein, human; D010281:Parathyroid Hormone; D010710:Phosphates; D005346:Fibroblast Growth Factors; D000089703:Fibroblast Growth Factor-23; D003404:Creatinine