title: Osteitis and synovitis, but not bone erosion, is associated with proteoglycan loss and microstructure damage in the cartilage of patients with rheumatoid arthritis.
abstract: OBJECTIVE
  To investigate the relation between anatomic changes of the synovium, the bone, the bone marrow and the cartilage to biochemical properties of the cartilage in patients with rheumatoid arthritis (RA).
  
  
  METHODS
  33 patients with RA received 3-T MRI scans of the metacarpophalangeal joints. Two independent methods, (A) the delayed gadolinium enhanced MRI of the cartilage (dGEMRIC, T2-mapping), which was used to assess the biochemical properties of the cartilage; (B) synovitis, osteitis and bone erosions were quantified according to the RA MRI scoring (RAMRIS) method and cartilage thickness (CT), interbone joint space (IBJS, distance between proximal and distal bone surface) and intercartilage joint space (ICJS, distance between proximal and distal cartilage surface) were measured.
  
  
  RESULTS
  Biochemical changes of the cartilage, corresponding to low dGEMRIC and high T2 values, were more likely to be seen in joints with decreased IBJS and ICJS as well as decreased CT. For instance, dGEMRIC was directly correlated to the IBJS (p=0.001) and ICJS (p=0.001), whereas T2 mapping was inversely correlated to IBJS and ICJS (both p=0.017). Moreover, the degree of osteitis, and to some extent synovitis, was correlated to biochemical cartilage changes as measured by dGEMRIC (p=0.003) or the T2 mapping (p=0.013). By contrast, bone erosions did not correlate to the degree of biochemical cartilage changes.
  
  
  CONCLUSIONS
  These data support the concept that synovitis and osteitis may be two main triggers for cartilage damage. Thus, the actual inflammatory state of a joint, but not so much the degree of bone erosion, appears to influence cartilage properties in RA.
authors.affiliation: Department of Internal Medicine 3, Rheumatology and Immunology, University of Erlangen-Nuremberg, , Erlangen, Germany.
authors.forename: Barbara
authors.initials: B
authors.lastname: Herz
authors.forename: Andreas
authors.initials: A
authors.lastname: Albrecht
authors.forename: Matthias
authors.initials: M
authors.lastname: Englbrecht
authors.forename: Götz H
authors.initials: GH
authors.lastname: Welsch
authors.forename: Michael
authors.initials: M
authors.lastname: Uder
authors.forename: Nina
authors.initials: N
authors.lastname: Renner
authors.forename: Philipp
authors.initials: P
authors.lastname: Schlechtweg
authors.forename: Dominik
authors.initials: D
authors.lastname: Paul
authors.forename: Lars
authors.initials: L
authors.lastname: Lauer
authors.forename: Klaus
authors.initials: K
authors.lastname: Engelke
authors.forename: Rolf
authors.initials: R
authors.lastname: Janka
authors.forename: Jürgen
authors.initials: J
authors.lastname: Rech
authors.forename: Georg
authors.initials: G
authors.lastname: Schett
authors.forename: Stephanie
authors.initials: S
authors.lastname: Finzel
mesh_terms: D000328:Adult; D001172:Arthritis, Rheumatoid / Q000378:metabolism* / Q000473:pathology; D001862:Bone Resorption; D002358:Cartilage, Articular / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008662:Metacarpophalangeal Joint / Q000378:metabolism* / Q000473:pathology; D008875:Middle Aged; D010000:Osteitis / Q000378:metabolism* / Q000473:pathology; D011509:Proteoglycans / Q000378:metabolism*; D013583:Synovial Membrane / Q000378:metabolism / Q000473:pathology; D013585:Synovitis / Q000378:metabolism* / Q000473:pathology
chemical_list: D011509:Proteoglycans
keywords: Inflammation; Magnetic Resonance Imaging; Outcomes research; Rheumatoid Arthritis; Synovitis