title: Bone turnover markers, osteoprotegerin and RANKL cytokines in children with cystic fibrosis.
abstract: OBJECTIVE
  Some scientific studies show decreased bone mineral density and increased fracture frequency in adult patients with cystic fibrosis (CF). The mechanism for early bone loss in CF patients are multifactorial: chronic pulmonary inflammation, malnutrition, reduced physical activity, delayed pubertal maturation. The aim of this study was to assess bone metabolism markers with special attention paid to osteoprotegerin (OPG) and receptor activator of nuclear factor κB ligand (RANKL) balance in CF children.
  
  
  METHODS
  The study included 35 children with diagnosed CF and 35 healthy controls aged 5-9 years (median 7.0 years). Serum levels of fat soluble vitamins were measured by chemiluminescence (vitamin D) and HPLC (vitamins A, E) methods. Concentrations of bone metabolism markers were determined by immunoenzymatic assay.
  
  
  RESULTS
  Mean levels of fat soluble vitamins (A, D, E) were lower in patients with CF compared to controls. In CF children we observed a significant (p<0.01) decrease in concentration of bone formation marker (osteocalcin) and similar bone resorption markers (CTX, TRACP5b) in comparison with healthy children. The serum level of OPG was significantly lower (p<0.05) and RANKL nearly 2-fold higher in patients with CF than in the healthy ones. The ratio of OPG to RANKL was about 2-fold lower in children with CF compared to healthy peers (p<0.01).
  
  
  CONCLUSIONS
  In CF children, an imbalance between bone formation and resorption processes occurs. An increase serum RANKL concentration coexisting with lower levels of OPG may be associated with intensification of bone resorption.
authors.forename: J
authors.initials: J
authors.lastname: Ambroszkiewicz
authors.forename: D
authors.initials: D
authors.lastname: Sands
authors.forename: J
authors.initials: J
authors.lastname: Gajewska
authors.forename: M
authors.initials: M
authors.lastname: Chelchowska
authors.forename: T
authors.initials: T
authors.lastname: Laskowska-Klita
mesh_terms: D000135:Acid Phosphatase / Q000097:blood; D015415:Biomarkers / Q000097:blood; D015519:Bone Density / Q000502:physiology; D001862:Bone Resorption / Q000378:metabolism*; D002118:Calcium / Q000097:blood; D002648:Child; D002675:Child, Preschool; D024042:Collagen Type I / Q000097:blood; D003550:Cystic Fibrosis / Q000378:metabolism*; D005260:Female; D006801:Humans; D007527:Isoenzymes / Q000097:blood; D008297:Male; D015675:Osteocalcin / Q000097:blood; D053244:Osteoprotegerin / Q000097:blood*; D010455:Peptides / Q000097:blood; D010710:Phosphates / Q000097:blood; D053245:RANK Ligand / Q000097:blood*; D000071681:Tartrate-Resistant Acid Phosphatase; D014801:Vitamin A / Q000097:blood; D014810:Vitamin E / Q000097:blood
chemical_list: D015415:Biomarkers; D024042:Collagen Type I; D007527:Isoenzymes; D053244:Osteoprotegerin; D010455:Peptides; D010710:Phosphates; D053245:RANK Ligand; C506030:TNFRSF11B protein, human; C505688:TNFSF11 protein, human; C052929:collagen type I trimeric cross-linked peptide; D015675:Osteocalcin; D014801:Vitamin A; D014810:Vitamin E; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase; D002118:Calcium