title: Serum levels of Dkk-1, sclerostin and VEGF in patients with ankylosing spondylitis and their association with smoking, and clinical, inflammatory and radiographic parameters.
abstract: OBJECTIVE
  To evaluate serum Dickkopf-1 (Dkk-1), sclerostin and vascular endothelial growth factor (VEGF) levels in patients with ankylosing spondylitis (AS) compared to healthy controls as well as their association with smoking, and clinical, inflammatory and radiographic parameters.
  
  
  METHODS
  Serum samples for total Dkk-1, sclerostin and VEGF were obtained from 57 tumour necrosis factor (TNF) inhibitor naïve patients with AS and 34 sex-, age- and body mass index (BMI)-matched controls. The erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), Bath AS Disease Activity Index (BASDAI), Bath AS Functional Index (BASFI), modified Stroke AS Spine Score (mSASSS) and smoking status were assessed for each patient.
  
  
  RESULTS
  There was no significant difference in serum bone metabolism markers between AS patients and controls. Dkk-1 levels were significantly (P<0.05) higher in AS patients with elevated ESR and CRP and no syndesmophytes, and were significantly (P<0.001) correlated with sclerostin levels (r=0.592). VEGF levels were significantly (P<0.05) higher in AS patients with current and ever smoking, elevated ESR and CRP, and high BASDAI and BASFI, and were significantly (P<0.05) correlated with ESR (r=0.284), CRP (r=0.285), BASDAI (r=0.349) and BASFI (r=0.275). In multivariate regression analyses, high Dkk-1 levels were significantly (P≤0.001) associated with elevated ESR and CRP, no syndesmophytes and high sclerostin levels, and high VEGF levels significantly (P<0.05) with ever smoking, and elevated ESR and CRP.
  
  
  CONCLUSIONS
  In AS, serum Dkk-1 concentrations appear to be related not only to syndesmophyte formation but also to systemic inflammation. Furthermore, high VEGF levels may be associated with smoking exposure.
authors.affiliation: Department of Rheumatology, 424 General Military Hospital, Ring Road N. Efkarpias, 564 03 Thessaloniki, Greece. Electronic address: sakelgr@gmail.com.
authors.forename: Grigorios T
authors.initials: GT
authors.lastname: Sakellariou
authors.affiliation: Department of Rheumatology, Veterans Administration Hospital (NIMTS), Athens, Greece.
authors.forename: Alexios
authors.initials: A
authors.lastname: Iliopoulos
authors.affiliation: Department of Rheumatology, Veterans Administration Hospital (NIMTS), Athens, Greece.
authors.forename: Maria
authors.initials: M
authors.lastname: Konsta
authors.affiliation: Academic Orthopaedic Unit, Aristotle University Medical School, Thessaloniki, Greece.
authors.forename: Eustathios
authors.initials: E
authors.lastname: Kenanidis
authors.affiliation: Academic Orthopaedic Unit, Aristotle University Medical School, Thessaloniki, Greece.
authors.forename: Michael
authors.initials: M
authors.lastname: Potoupnis
authors.affiliation: Academic Orthopaedic Unit, Aristotle University Medical School, Thessaloniki, Greece.
authors.forename: Eleftherios
authors.initials: E
authors.lastname: Tsiridis
authors.affiliation: Laboratories "Analysis", Thessaloniki, Greece.
authors.forename: Elpida
authors.initials: E
authors.lastname: Gavana
authors.affiliation: Academic Orthopaedic Unit, Aristotle University Medical School, Thessaloniki, Greece.
authors.forename: Fares E
authors.initials: FE
authors.lastname: Sayegh
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000328:Adult; D019485:Bone Morphogenetic Proteins / Q000097:blood*; D003430:Cross-Sectional Studies; D005260:Female; D005819:Genetic Markers; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000097:blood*; D008297:Male; D012907:Smoking / Q000009:adverse effects*; D013167:Spondylitis, Ankylosing / Q000097:blood* / Q000175:diagnosis* / Q000000981:diagnostic imaging; D042461:Vascular Endothelial Growth Factor A / Q000097:blood*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D019485:Bone Morphogenetic Proteins; C501126:DKK1 protein, human; D005819:Genetic Markers; D036341:Intercellular Signaling Peptides and Proteins; C422903:SOST protein, human; D042461:Vascular Endothelial Growth Factor A
keywords: Ankylosing spondylitis; Dickkopf-1; Sclerostin; Smoking; VEGF; mSASSS