Endogenous glutamate in association with inflammatory and hormonal factors modulates bone tissue resorption of the temporomandibular joint in patients with early rheumatoid arthritis.
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.
Hajati
Anna-Kari
AK
Department of Clinical Oral Physiology, Institute of Odontology, Karolinska Institutet, Huddinge, Sweden. anna-kari.hajati@ki.se
Alstergren
Per
P
Näsström
Karin
K
Bratt
Johan
J
Kopp
Sigvard
S
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*
D018836:Inflammation Mediators; D018698:Glutamic Acid; D013739:Testosterone; D004958:Estradiol; D002097:C-Reactive Protein; D012217:Rheumatoid Factor
Arthritis Rheum. 2007 Aug;56(8):2523-34
17665433
Int J Biochem Cell Biol. 2007;39(6):1089-104
17188550
Anat Rec A Discov Mol Cell Evol Biol. 2003 Oct;274(2):934-41
12973717
Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2005 Apr;99(4):455-63
15772594
FASEB J. 2001 Jul;15(9):1586-8
11427494
Ann Rheum Dis. 2002 Nov;61 Suppl 2:ii84-6
12379632
Blood. 1998 Jan 1;91(1):134-41
9414277
Acta Odontol Scand. 2003 Feb;61(1):57-64
12635783
Arthritis Rheum. 2000 Jul;43(7):1473-7
10902748
J Musculoskelet Neuronal Interact. 2002 Sep;2(5):423-31
15758410
J Rheumatol. 2004 Feb;31(2):214-22
14760787
Ann Rheum Dis. 1996 Nov;55(11):811-5
8976637
J Musculoskelet Neuronal Interact. 2002 Mar;2(3):282-4
15758455
Scand J Rheumatol. 1985;14(4):393-402
4081662
Bone. 1998 Apr;22(4):295-9
9556127
Scand J Rheumatol. 1995;24(1):22-5
7863273
Rheumatology (Oxford). 2001 Jun;40(6):691-4
11426029
Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 1996 May;81(5):613-8
8734713
J Rheumatol. 2000 Jul;27(7):1622-31
10914842
Arthritis Rheum. 2004 Jun;50(6):1967-75
15188374
Arthritis Rheum. 1988 Mar;31(3):315-24
3358796
Endocrinology. 2001 Jun;142(6):2205-12
11356664
J Rheumatol. 2003 Nov;30(11):2338-43
14677174
Clin Exp Immunol. 2004 Sep;137(3):621-7
15320917
Acta Odontol Scand. 2004 Feb;62(1):7-13
15124777
Endocr Rev. 2007 Aug;28(5):521-74
17640948
Swed Dent J. 1987;11(1-2):11-22
3473706
Pain. 2000 May;86(1-2):69-74
10779662
J Cell Sci. 2006 Apr 1;119(Pt 7):1283-96
16522681
Arthritis Rheum. 2001 May;44(5):1003-12
11352231
Ann N Y Acad Sci. 2006 Jun;1069:391-400
16855166
J Cereb Blood Flow Metab. 2005 Apr;25(4):513-9
15660099
Acta Odontol Scand. 1987 Apr;45(2):65-75
3474856
Endocrinology. 2004 May;145(5):2384-91
14726437
Endocr Rev. 2002 Jun;23(3):279-302
12050121