title: Plasma and synovial fluid sclerostin are inversely associated with radiographic severity of knee osteoarthritis.
abstract: OBJECTIVE
  The purpose of this study was to analyze sclerostin in plasma and synovial fluid of knee osteoarthritis (OA) patients and to investigate the association between sclerostin levels and radiographic severity.
  
  
  METHODS
  A total of 190 subjects (95 knee OA patients and 95 healthy controls) were recruited in the present study. Sclerostin levels in plasma and synovial fluid were assessed using an enzyme-linked immunosorbent assay. OA grading was performed using the Kellgren-Lawrence classification.
  
  
  RESULTS
  Plasma sclerostin levels were significantly lower in OA patients than in healthy controls (P=0.004). Additionally, sclerostin levels in plasma were significantly higher with respect to paired synovial fluid (P<0.001). Moreover, sclerostin levels in plasma and synovial fluid demonstrated a significant inverse correlation with the radiographic severity of knee OA (r=-0.464, P<0.001 and r=-0.592, P<0.001, respectively). Subsequent analysis revealed that there was a positive correlation between plasma and synovial sclerostin levels (r=0.657, P<0.001).
  
  
  CONCLUSIONS
  Sclerostin was significantly lower in OA plasma samples when compared with healthy controls. Plasma and synovial fluid sclerostin levels were inversely associated with the radiographic severity of knee OA. Therefore, sclerostin may be utilized as a biochemical marker for reflecting disease severity in primary knee OA.
authors.affiliation: Department of Biochemistry, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok 10330, Thailand.
authors.forename: Thomas
authors.initials: T
authors.lastname: Mabey
authors.affiliation: Department of Biochemistry, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok 10330, Thailand; Department of Orthopaedics, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok 10330, Thailand. Electronic address: Sittisak.H@chula.ac.th.
authors.forename: Sittisak
authors.initials: S
authors.lastname: Honsawek
authors.affiliation: Department of Orthopaedics, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok 10330, Thailand.
authors.forename: Aree
authors.initials: A
authors.lastname: Tanavalee
authors.affiliation: Department of Orthopaedics, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok 10330, Thailand.
authors.forename: Vajara
authors.initials: V
authors.lastname: Wilairatana
authors.affiliation: Department of Orthopaedics, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok 10330, Thailand.
authors.forename: Pongsak
authors.initials: P
authors.lastname: Yuktanandana
authors.affiliation: Department of Biochemistry, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok 10330, Thailand.
authors.forename: Natthaphon
authors.initials: N
authors.lastname: Saetan
authors.affiliation: Department of Biochemistry, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok 10330, Thailand.
authors.forename: Dong
authors.initials: D
authors.lastname: Zhan
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000368:Aged; D019485:Bone Morphogenetic Proteins / Q000097:blood* / Q000378:metabolism*; D016022:Case-Control Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005819:Genetic Markers; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology; D008297:Male; D020370:Osteoarthritis, Knee / Q000097:blood* / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology*; D011859:Radiography; D013582:Synovial Fluid / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D019485:Bone Morphogenetic Proteins; D005819:Genetic Markers; C422903:SOST protein, human
keywords: Osteoarthritis; Plasma; Radiographic severity; Sclerostin; Synovial fluid