title: Osteoclast function, bone turnover and inflammatory cytokines during infective exacerbations of cystic fibrosis.
abstract: BACKGROUND
  Raised levels of pro-inflammatory, pro-resorptive cytokines during pulmonary infection may contribute to osteoporosis in cystic fibrosis (CF). We assessed osteoclast number and activity during infective exacerbations and examined their relationship to serum inflammatory cytokines and bone turnover markers.
  
  
  METHODS
  Serum samples from 24 adults with CF were obtained before, during and after treatment of infection. Osteoclastic cells were generated from peripheral blood mononuclear cells and their number and activity assessed. Serum osteocalcin, type 1 collagen cross-linked N-telopeptide (NTx), interleukin-6 (IL-6), tumour necrosis factor alpha (TNFalpha), receptor activator of NFkB ligand (RANKL) and osteoprotegerin (OPG) were measured.
  
  
  RESULTS
  Osteoclast number and activity were increased at the start of exacerbation and decreased with antibiotic therapy. Significant correlations were demonstrated between osteoclast formation and serum TNFalpha, OPG, osteocalcin and NTx and between osteoclast activity and serum IL-6 and NTx.
  
  
  CONCLUSIONS
  The systemic response to infection is associated with increased bone resorptive activity in patients with CF.
authors.affiliation: Department of Haematology, Addenbrooke's Hospital, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK.
authors.forename: Elizabeth F
authors.initials: EF
authors.lastname: Shead
authors.forename: Charles S
authors.initials: CS
authors.lastname: Haworth
authors.forename: Helen
authors.initials: H
authors.lastname: Barker
authors.forename: Diana
authors.initials: D
authors.lastname: Bilton
authors.forename: Juliet E
authors.initials: JE
authors.lastname: Compston
mesh_terms: D000328:Adult; D001424:Bacterial Infections / Q000150:complications*; D016723:Bone Remodeling; D002452:Cell Count; D024042:Collagen Type I / Q000097:blood; D003550:Cystic Fibrosis / Q000382:microbiology* / Q000473:pathology / Q000503:physiopathology*; D016207:Cytokines / Q000097:blood*; D005260:Female; D006801:Humans; D018836:Inflammation Mediators / Q000097:blood*; D015850:Interleukin-6 / Q000097:blood; D008297:Male; D015675:Osteocalcin / Q000097:blood; D010010:Osteoclasts / Q000473:pathology*; D053244:Osteoprotegerin / Q000097:blood; D010455:Peptides / Q000097:blood; D011552:Pseudomonas Infections / Q000150:complications; D011550:Pseudomonas aeruginosa; D012720:Severity of Illness Index; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D055815:Young Adult
chemical_list: D024042:Collagen Type I; D016207:Cytokines; D018836:Inflammation Mediators; D015850:Interleukin-6; D053244:Osteoprotegerin; D010455:Peptides; D014409:Tumor Necrosis Factor-alpha; C052929:collagen type I trimeric cross-linked peptide; D015675:Osteocalcin