title: Decreased local and systematic matrix Gla protein (MGP) expression and its link to radiographic progression in ankylosing spondylitis patients.
abstract: BACKGROUND
  Decreased serum levels of uncarboxylated matrix Gla-protein (ucMGP) have been detected in Ankylosing Spondylitis (AS) patients. The current study was to investigate the expression of MGP in AS tissues as well as the relationship between serum ucMGP (an inactive form of MGP) levels and radiographic severity in AS patients.
  
  
  METHODS
  Local MGP expression were assessed by Western blot and RT-PCR in hip synovial tissues from patients with AS and control subjects. In addition, the serum level of ucMGP was assessed by enzyme-linked immunosorbent assay in 68 healthy subjects and 62 patients with AS. The radiographic progression of AS was classified according to the radiographic events of modified New York Criteria for sacroiliac joint evaluation and modified Stoke Ankylosing Spondylitis Spine Score (mSASSS) system for spine assessment.
  
  
  RESULTS
  MGP expression was downregulated in AS patients compared to controls in hip tissues. Decreased levels of ucMGP in serum were found in AS patients compared with healthy controls. ucMGP levels in serum of AS patients were significantly negatively correlated with the disease radiographic severity evaluated by modified New York grading criteria (r = -0.293, p = 0.045) and mSASSS system (r = -0.361, p = 0.03).
  
  
  CONCLUSIONS
  MGP expression is impaired in patients with AS. A low serum level of ucMGP in the setting of AS is linked to increased structural damage, emphasizing the role of MGP in the suppression of new bone formation.
authors.forename: Dai-He
authors.initials: DH
authors.lastname: Li
authors.forename: Hong-Dan
authors.initials: HD
authors.lastname: Fu
authors.forename: Wan-Lin
authors.initials: WL
authors.lastname: Liu
authors.forename: Yi-Shan
authors.initials: YS
authors.lastname: Wei
authors.forename: Dian-Ming
authors.initials: DM
authors.lastname: Jiang
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D001842:Bone and Bones / Q000000981:diagnostic imaging; D002135:Calcium-Binding Proteins / Q000097:blood*; D050659:Core Binding Factor Alpha 1 Subunit / Q000097:blood; D018450:Disease Progression; D015536:Down-Regulation; D004797:Enzyme-Linked Immunosorbent Assay; D016326:Extracellular Matrix Proteins / Q000097:blood*; D005260:Female; D006615:Hip / Q000000981:diagnostic imaging / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012313:RNA / Q000032:analysis; D011859:Radiography; D060888:Real-Time Polymerase Chain Reaction; D055758:SOX9 Transcription Factor / Q000097:blood; D012720:Severity of Illness Index; D013131:Spine / Q000000981:diagnostic imaging; D013167:Spondylitis, Ankylosing / Q000097:blood* / Q000000981:diagnostic imaging*; D013583:Synovial Membrane / Q000473:pathology; D000097568:Matrix Gla Protein
chemical_list: D015415:Biomarkers; D002135:Calcium-Binding Proteins; D050659:Core Binding Factor Alpha 1 Subunit; D016326:Extracellular Matrix Proteins; D012313:RNA; D055758:SOX9 Transcription Factor; D000097568:Matrix Gla Protein; C493709:RUNX2 protein, human; C527932:SOX9 protein, human