title: Endogenous glutamate in association with inflammatory and hormonal factors modulates bone tissue resorption of the temporomandibular joint in patients with early rheumatoid arthritis.
abstract: OBJECTIVE
  The aim of this study was to investigate the relation between plasma level of glutamate and extent of radiographic bone erosion of the temporomandibular joint (TMJ) in patients with early rheumatoid arthritis (RA) in relation to inflammatory disease activity as well as estradiol and testosterone.
  
  
  METHODS
  A total of 47 patients (29 women and 18 men) of whom 24 were seropositive were included shortly after being diagnosed with RA. Radiographic signs of bone tissue resorption (erosions) in the TMJ were recorded by cone-beam CT images, and an erosion score (0 to 24) was calculated for each patient. Venous blood was analyzed for rheumatoid factor, C-reactive protein, erythrocyte sedimentation rate, leukocyte particle count, glutamate, estradiol, and testosterone. Nonparametric statistical methods were used in the analysis.
  
  
  RESULTS
  Resorptive changes of the TMJ were found in a major part of the patients. There was a significant positive correlation between plasma level of glutamate and extension of radiographic erosions that was strongest in the patients with low levels of C-reactive protein, estradiol, or testosterone. By contrast, erosions were correlated with C-reactive protein in patients with high levels of estradiol. The highest levels of glutamate were found in patients with low levels of C-reactive protein and estradiol.
  
  
  CONCLUSIONS
  This study shows that a majority of patients with early RA presents radiographic signs of bone tissue resorption of the TMJ and that circulating glutamate is associated with the extent of these changes. The relationship between glutamate and bone resorption seems to be influenced by systemic inflammatory activity as well as estradiol and testosterone levels.
authors.affiliation: Department of Clinical Oral Physiology, Institute of Odontology, Karolinska Institutet, Huddinge, Sweden. anna-kari.hajati@ki.se
authors.forename: Anna-Kari
authors.initials: AK
authors.lastname: Hajati
authors.forename: Per
authors.initials: P
authors.lastname: Alstergren
authors.forename: Karin
authors.initials: K
authors.lastname: Näsström
authors.forename: Johan
authors.initials: J
authors.lastname: Bratt
authors.forename: Sigvard
authors.initials: S
authors.lastname: Kopp
mesh_terms: D000368:Aged; D001172:Arthritis, Rheumatoid / Q000097:blood* / Q000000981:diagnostic imaging / Q000473:pathology; D001799:Blood Sedimentation; D001862:Bone Resorption / Q000097:blood / Q000000981:diagnostic imaging / Q000473:pathology*; D002097:C-Reactive Protein / Q000032:analysis; D054893:Cone-Beam Computed Tomography; D004958:Estradiol / Q000097:blood*; D005260:Female; D018698:Glutamic Acid / Q000097:blood*; D006801:Humans; D018836:Inflammation Mediators / Q000097:blood; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D012217:Rheumatoid Factor / Q000097:blood; D012737:Sex Factors; D013704:Temporomandibular Joint / Q000000981:diagnostic imaging / Q000473:pathology*; D013705:Temporomandibular Joint Disorders / Q000097:blood* / Q000000981:diagnostic imaging / Q000473:pathology; D013739:Testosterone / Q000097:blood*
chemical_list: D018836:Inflammation Mediators; D018698:Glutamic Acid; D013739:Testosterone; D004958:Estradiol; D002097:C-Reactive Protein; D012217:Rheumatoid Factor
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