title: Cinacalcet lowers FGF-23 level together with bone metabolism in hemodialyzed patients with secondary hyperparathyroidism.
abstract: OBJECTIVE
  Secondary hyperparathyroidism (sHPT) is associated with elevated levels of FGF-23, which in turn are connected to adverse outcomes in ESRD patients. The relationship between FGF-23 and bone metabolism in patients with sHPT treated with cinacalcet has not been studied.
  
  
  METHODS
  Thirty-four stable chronically hemodialyzed patients with sHPT were prospectively followed during the treatment with cinacalcet without any changes in concurrent vitamin D or phosphate binder dose. Blood samples were collected at the start and after 6 months of study. Levels of osteocalcin (OC), cross-linked C-telopeptide of type I collagen (CTX), and FGF-23 were measured.
  
  
  RESULTS
  Eighteen patients finished the study. Levels of calcium, phosphate, and iPTH decreased during 6 months of treatment with cinacalcet. Serum level of FGF-23 decreased significantly (log FGF-23 from 7.58 ± 1.7 to 6.61 ± 1.7 pg/ml) (P < 0.001). Cinacalcet lowered the concentration of CTX from 3.1 ± 0.6 ng/ml to 2.6 ± 0.9 ng/ml (P < 0.05) and OC from 91.8 (41.5-558.6) to 70.3 (11.3-419.7) ng/ml (P < 0.05). The magnitude of change in FGF-23 concentration before and after treatment correlated significantly with suppression of osteoblasts' function assessed by ΔOC (r = 0.5, P < 0.05) but not with changes in bone resorption marker ΔCTX.
  
  
  CONCLUSIONS
  Cinacalcet treatment of sHPT results in reduction of FGF-23 levels, probably due to the suppression of osteoblasts function.
authors.affiliation: Department of Nephrology and Transplantation, Medical University of Bialystok, Ul. Zurawia 14, 15-540 Bialystok, Poland. tomhry@mp.pl
authors.forename: Tomasz
authors.initials: T
authors.lastname: Hryszko
authors.forename: Szymon
authors.initials: S
authors.lastname: Brzosko
authors.forename: Alicja
authors.initials: A
authors.lastname: Rydzewska-Rosolowska
authors.forename: Ewa
authors.initials: E
authors.lastname: Koc-Zorawska
authors.forename: Michal
authors.initials: M
authors.lastname: Mysliwiec
mesh_terms: D000368:Aged; D001842:Bone and Bones / Q000187:drug effects* / Q000378:metabolism*; D057966:Calcimimetic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D000069449:Cinacalcet; D024042:Collagen Type I / Q000097:blood; D005260:Female; D000089703:Fibroblast Growth Factor-23; D005346:Fibroblast Growth Factors / Q000097:blood*; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000097:blood* / Q000188:drug therapy; D008297:Male; D008875:Middle Aged; D009281:Naphthalenes / Q000494:pharmacology* / Q000627:therapeutic use; D010006:Osteoblasts / Q000187:drug effects; D015675:Osteocalcin / Q000097:blood; D010281:Parathyroid Hormone / Q000097:blood; D010455:Peptides / Q000097:blood; D006435:Renal Dialysis / Q000009:adverse effects; D051436:Renal Insufficiency, Chronic / Q000628:therapy
chemical_list: D057966:Calcimimetic Agents; D024042:Collagen Type I; C000717427:FGF23 protein, human; D009281:Naphthalenes; D010281:Parathyroid Hormone; D010455:Peptides; C052929:collagen type I trimeric cross-linked peptide; D015675:Osteocalcin; D005346:Fibroblast Growth Factors; D000089703:Fibroblast Growth Factor-23; D000069449:Cinacalcet