title: Osteoprotegerin correlates with disease activity and endothelial activation in non-diabetic ankylosing spondylitis patients undergoing TNF-α antagonist therapy.
abstract: OBJECTIVE
  Osteoprotegerin (OPG) has been associated with increased risk and severity of atherosclerotic disease in the general population. Since ankylosing spondylitis (AS) is a chronic inflammatory disease associated with accelerated atherosclerosis, we aimed to assess whether OPG levels correlate with disease activity, systemic inflammation, metabolic syndrome, adipokines and biomarkers of endothelial cell activation in patients with AS undergoing TNF-α antagonist therapy.
  
  
  METHODS
  We assessed OPG plasma concentration in 30 non-diabetic AS patients without cardiovascular disease undergoing TNF-α antagonist-infliximab therapy. OPG levels were measured immediately before and after an infliximab infusion. Correlations of OPG levels with disease activity, clinical characteristics, systemic inflammation, metabolic syndrome features, adipokines and biomarkers of endothelial activation were assessed. Changes in OPG concentration following an infusion of anti-TNF-α monoclonal antibody-infliximab were also analysed.
  
  
  RESULTS
  We found a positive correlation between OPG levels and markers of disease activity such as BASDAI and VAS spinal pain (r=0.497, p=0.01; r=0.390; p=0.04, respectively). No differences in OPG levels according to specific clinical features of the disease were seen. An inverse correlation between OPG levels and total cholesterol and LDL-cholesterol was also found (r=-0.451; p=0.02 and r=-0.411; p=0.03, respectively). A correlation between OPG and asymmetric dimethylarginine, a biomarker of endothelial cell activation, was also disclosed (r=0.533; p=0.01). No correlation between OPG level and insulin resistance was observed. An infliximab infusion did not lead to a significant reduction in OPG levels.
  
  
  CONCLUSIONS
  OPG shows a correlation with markers of disease activity and endothelial activation in non-diabetic ankylosing spondylitis patients undergoing TNF-α antagonist therapy.
authors.affiliation: Epidemiology, Genetics and Atherosclerosis Research Group on Systemic Inflammatory Diseases, Rheumatology Division, IFIMAV, Santander, Spain. fernandagenre@gmail.com.
authors.forename: Fernanda
authors.initials: F
authors.lastname: Genre
authors.forename: Raquel
authors.initials: R
authors.lastname: López-Mejías
authors.forename: José A
authors.initials: JA
authors.lastname: Miranda-Filloy
authors.forename: Begoña
authors.initials: B
authors.lastname: Ubilla
authors.forename: Beatriz
authors.initials: B
authors.lastname: Carnero-López
authors.forename: Natalia
authors.initials: N
authors.lastname: Palmou-Fontana
authors.forename: Inés
authors.initials: I
authors.lastname: Gómez-Acebo
authors.forename: Ricardo
authors.initials: R
authors.lastname: Blanco
authors.forename: Javier
authors.initials: J
authors.lastname: Rueda-Gotor
authors.forename: Trinitario
authors.initials: T
authors.lastname: Pina
authors.forename: Carlos
authors.initials: C
authors.lastname: González-Juanatey
authors.forename: Javier
authors.initials: J
authors.lastname: Llorca
authors.forename: Miguel Á
authors.initials: MÁ
authors.lastname: González-Gay
mesh_terms: D054392:Adipokines / Q000097:blood; D000328:Adult; D000368:Aged; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use*; D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D015415:Biomarkers / Q000097:blood; D042783:Endothelial Cells / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D005260:Female; D006801:Humans; D018836:Inflammation Mediators / Q000097:blood; D000069285:Infliximab; D008297:Male; D008875:Middle Aged; D053244:Osteoprotegerin / Q000097:blood*; D012720:Severity of Illness Index; D013167:Spondylitis, Ankylosing / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy* / Q000276:immunology; D016896:Treatment Outcome; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors*
chemical_list: D054392:Adipokines; D000893:Anti-Inflammatory Agents; D000911:Antibodies, Monoclonal; D015415:Biomarkers; D018836:Inflammation Mediators; D053244:Osteoprotegerin; C506030:TNFRSF11B protein, human; D014409:Tumor Necrosis Factor-alpha; D000069285:Infliximab