Specific expression of inducible nitric oxide synthase in the synovium of the diseased temporomandibular joint

OBJECTIVE: The expression of inducible nitric oxide synthase (iNOS) in temporomandibular joint (TMJ) specimens obtained arthroscopically from diseased TMJs was investigated by using immunohistochemistry and compared with clinical, arthroscopic, and histologic findings. STUDY DESIGN: Synovial biopsies were obtained arthroscopically from 18 TMJs in 15 patients with symptomatic internal derangement (ID) or osteoarthritis (OA). We also obtained arthroscopic biopsies from 8 control TMJs (3 with habitual luxation of the mandible, one with ID with clicking, and 4 with mandibular condyle fractures). The expression of iNOS was examined by immunohistochemistry and was compared with clinical, arthroscopic, and histologic findings. RESULTS: Definite or intense iNOS immunoreactivity was observed in both the synovial lining cells and the endothelial cells of TMJs with symptomatic ID or OA. Weaker immunoreactivity was present in synovial fibroblasts. In contrast, in TMJs without synovitis (eg, those with habitual luxation of the mandible) the expression of iNOS was weak or marginal. The expression of iNOS correlated significantly with arthroscopic evidence of synovitis (r = 0.406, P <.05) but not with cartilaginous degeneration (P >.05). The expression of iNOS also correlated with the histologic grade of the synovial lining cell layers (r = 0.530, P <.05). However, in patients with ID or OA of the TMJ, there was no statistically significant correlation between the intensity of iNOS immunoreactivity and clinical, arthroscopic, or histologic findings (P >.05). CONCLUSION: These data clearly suggest that nitric oxide is locally produced in the synovial lining of the TMJ in ID and OA.     

Bone morphogenetic protein-2 in temporomandibular joints with internal derangement

OBJECTIVE: The purpose of this study was to analyze the expression of bone morphogenetic protein-2 (BMP-2) in patients with internal derangement of the temporomandibular joint. STUDY DESIGN: Twenty-one human temporomandibular joint samples (5 extirpated disks and 16 biopsy specimens of synovitis area from patients with internal derangement of the TMJ) and 2 control temporomandibular joint specimens (2 normal disks obtained by autopsy) were analyzed with specific antibodies through use of an immunohistochemical technique. RESULTS: BMP-2 was predominantly localized in chondrocytes around the damaged areas of the articular disks. BMP-2 expression was also found in synovial cells and endothelial cells of blood vessels. Control specimens demonstrated BMP-2 staining in synovial lining cells and endothelial cells of blood vessels. However, the chondrocytes in the normal cartilage layers of the control specimens showed no staining. CONCLUSIONS: These findings suggest that BMP-2 may be involved in the pathogenesis of osteoarthritic changes or the repair process of temporomandibular joint internal derangement.     

The expression of tenascin mRNA in human temporomandibular joint specimens

The expression of mRNA of tenascin in the temporomandibular joint (TMJ) disc and synovial membrane was examined in 20 human TMJ samples from patients with internal derangement of the TMJ and 10 control specimens by in situ hybridization technique using paraffine-embedded tissue, and antisense and sense cRNA probes. In control specimens, tenascin mRNA was not expressed. However, we were able to find tenascin mRNA expression in the surgical specimens. In 15 of 20 samples, ranging numbers of synovial cells expressed tenascin mRNA in the hypertrophic synovial membranes. Also, in 6 of 20 samples, tenascin mRNA was identified in fibroblasts. In four specimens, vascular endothelial cells were positive for the mRNA. In internal derangement cases, histopathological findings are often found such as synovitis, new capillary growth and fibrosis. The present study demonstrates that tenascin is produced specifically in synovial cells, vascular endothelial cells and fibroblasts affected in the portion of TMJ with internal derangement.     

Expression of interleukin 6 in synovial tissues in patients with internal derangement of the temporomandibular joint

Using an immunohistochemical technique, we examined synovial tissue from 46 temporomandibular joints (TMJ) with internal derangement in 44 patients. As controls, we examined synovial tissue specimens from 7 joints with habitual dislocation without pain. In synovial tissues from 21 of the 46 joints with internal derangement, interleukin 6 (IL-6) was expressed in the synovial lining cells and in the mononuclear cells infiltrating the periphery of the blood vessels. The density of IL-6-stained cells in specimens with internal derangement correlated significantly with the grade of joint effusion shown by magnetic resonance imaging (P=0.01, r=0.32).     

Association between arthroscopic diagnosis of temporomandibular joint osteoarthritis and synovial fluid nitric oxide levels.

OBJECTIVE: The purpose of this study was to determine whether there is a relationship between synovial fluid levels of nitric oxide and clinical and arthroscopic findings of synovitis or cartilaginous degeneration. STUDY DESIGN: Arthroscopic surgery was performed on 20 joints in 15 female patients with internal derangement and osteoarthritis of the temporomandibular joint. Synovial fluid aspirates were obtained immediately before arthroscopy. Synovial fluid was also obtained from 14 joints of 11 female asymptomatic volunteers. The concentration of nitrite in the fluid recovered from each temporomandibular joint was measured through use of a highly sensitive and specific chemiluminescence detection method, calibrated per 1 mg of synovial fluid protein and expressed as nitric oxide; the result was then compared with clinical and arthroscopic findings of synovitis and cartilaginous degeneration. RESULTS: Significantly higher levels of nitric oxide (median, 0.331 micromol/mg) were seen in the patients with internal derangement and osteoarthritis than in the control group (median, 0.001 micromol/mg; P<.0001). Synovial fluid from joints with pain in the joint area had significantly higher levels of nitric oxide than did fluid from joints without such pain. Synovial fluid from joints with degenerative changes (median, 0.467 micromol/mg) had significantly higher levels of nitric oxide than did fluid from joints without osteoarthritis (median, 0.057 micromol/mg; P<.05). Although the levels of nitric oxide in synovial fluid aspirates were markedly elevated in some joints with synovitis, there was no correlation between the levels of nitric oxide and the presence of synovitis. CONCLUSIONS: The findings indicate that increased levels of nitric oxide are involved in the pathogenesis of cartilaginous degeneration of the temporomandibular joint.     

Inducible nitric oxide synthase and apoptosis-related factors in the synovial tissues of temporomandibular joints with internal derangement and osteoarthritis.

PURPOSE: In this study, we investigated the relationship between oxidative stress and apoptosis in synovial tissues in temporomandibular joint diseases (TMDs), including internal derangement (ID) and osteoarthritis (OA), comparing immunohistochemical, arthroscopic, and histologic findings. MATERIALS AND METHODS: Synovial specimens obtained from patients with ID (31 patients), osteoarthritis (11 patients), and condylar fractures of the mandible (5 patients) during arthroscopy were examined immunohistochemically using antibodies against CD68, inducible nitric oxide synthase (iNOS), Fas, and single-stranded DNA (ssDNA). RESULTS: CD68 and iNOS immunoreactivity were detected mainly in synovial lining cells and subintimal macrophages, and tended to increase with synovial hyperplasia. Fas and ssDNA immunoreactivity was detected mainly in synovial lining cells, and Fas-positive regions exhibited a number of ssDNA-positive cells. Fas expression was significantly greater in fractures than in OA, and ssDNA expression was significantly greater in OA than in ID. Fas expression was significantly greater in iNOS-positive versus iNOS-negative TMJs, and ssDNA expression tended to increase with iNOS expression. CONCLUSION: These immunohistochemical findings suggest that oxidative stress and apoptosis in synovial tissues are involved in the onset and progression of TMDs.     

Relationship of calcitonin gene-related peptide in synovial tissues and temporomandibular joint pain in humans

OBJECTIVE: To elucidate the expression of calcitonin gene-related peptide (CGRP) in synovial tissue taken from the human temporomandibular joint (TMJ) with internal derangement, and discuss the relationship between CGRP and joint pain. STUDY DESIGN: Using an immunohistochemical technique, 48 joints in 48 patients were examined. As controls, synovial tissue specimens from 7 joints with habitual dislocation without pain were also examined. RESULTS: In all of the internal derangement and control subjects, CGRP-positive cells were observed in the connective tissues around the blood vessels beneath the lining cells. The extent score of CGRP was significantly higher in the internal derangement group than in the control group (P=.033). There was a significant positive correlation between the extent score of CGRP and joint pain (P=.036, r=0.30). CONCLUSIONS: These results suggest that the expression of CGRP is increased in the synovial tissues from patients with internal derangement, and that CGRP seems to play an important role in the mechanism of pain production in patients with symptomatic internal derangement.     

Specific expression of interleukin-1 beta in temporomandibular joints with internal derangement: correlation with clinical findings.

OBJECTIVE: Interleukin-1 beta appears to play an important role in the pathophysiology of joint diseases. The aim of this study was to analyze the expression of interleukin-1 beta in temporomandibular joint internal derangement. STUDY DESIGN: Using an immunohistochemical technique with specific antibodies, we examined 20 human temporomandibular joint samples from patients with internal derangement of the temporomandibular joint: 5 extirpated disks and 15 biopsy specimens from the synovitic area of the temporomandibular joint upper compartment. We also examined 2 control specimens. The evaluation of interleukin-1 beta expression compared with clinical findings. RESULTS: Interleukin-1 beta was predominantly localized in the synovial lining cells and endothelial cells of blood vessels. Statistically significant correlation was found between interleukin-1 beta expression and some clinical findings. CONCLUSIONS: The results suggest that interleukin-1 beta may be involved in the pathogenesis of temporomandibular joint internal derangement and that the intensity of interleukin-1 beta expression may correlate with clinical findings, especially pain.     

Specific expression of substance P in synovial tissues of patients with symptomatic, non-reducing internal derangement of the temporomandibular joint: comparison with clinical findings

Our aim was to find out the extent of expression of substance P in synovial tissue from the human temporomandibular joints (TMJ) with symptomatic, non-reducing internal derangement, and to investigate the relationship between substance P and clinical findings. Fifty-four joints in 54 patients were examined immunohistochemically. Specimens of synovial tissue from 10 joints in 8 subjects with habitual dislocation of the TMJ with no pain were examined as controls. Cells that stained for substance P were found mainly among the endothelial cells in the blood vessels beneath the lining cells in synovial tissues from 47 of the 54 joints (87%) with internal derangement and from 5 of the 10 control joints. The extent score of cells that stained for substance P in joints with internal derangement was significantly higher than that in controls (p=0.02). The extent score of these cells did not correlate with pain in the joint or the degree of synovitis. These results suggest that substance P may have some roles in both the physiological and pathological conditions in patients with symptomatic internal derangement of the TMJ.     

The expression of vascular endothelial growth factor in synovial tissues in patients with internal derangement of the temporomandibular joint

OBJECTIVE: The aim of this study was to elucidate the expression and localization of vascular endothelial growth factor (VEGF) in synovial tissue taken from the temporomandibular joint (TMJ) with internal derangement (ID) and discuss the role of VEGF in the pathogenesis of ID. STUDY DESIGN: Through the use of an immunohistochemical technique, 39 TMJs in 37 patients were examined. As controls, synovial tissue specimens from 6 joints in 6 patients with habitual dislocation were also examined. RESULTS: In the synovial tissue from 35 of the patients with ID, expression of VEGF was observed in the synovial lining cells, in the endothelial cells of the blood vessels, and in the fibroblasts. In contrast, expression of VEGF was found in the TMJ tissue from only 2 of the controls. The percentage of VEGF-positive cells in the ID specimens was significantly higher than that in the habitual dislocation specimens (P < .02), and the expression of VEGF significantly correlated with the arthroscopic synovitis score (P = .004). CONCLUSION: These results suggest that the expression of VEGF is upregulated and involved in the development of inflammatory changes in synovial tissues in TMJs with ID.     

The distribution of cyclooxygenase-1 in human temporomandibular joint samples: an immunohistochemical study

Cyclooxygenase-1,2 (COX-1,2) or prostaglandin (PG) H synthase, is the first enzyme of the pathway in which arachidonic acid is oxidized to PGs. Thus, we examined the expression of COX-1 in 16 human temporomandibular joint (TMJ) samples with internal derangement and in 10 control specimens by an immunohistological technique using paraffin-embedded tissue and specific antihuman COX-1 polyclonal antibody. There was obvious distinction of COX-1 immunoreactivity between the control specimens and internal derangement cases, at the endothelial cells and fibroblasts, in the region of posterior and/or anterior loose connective tissues and synovial membrane. The findings of the present study suggest that COX-1 might be an important mechanism for maintaining normal homeostasis at the endothelial cells and fibroblasts with internal derangement of TMJ.     

The immunohistochemical distribution of vimentin in human temporomandibular joint samples

The aim of this investigation was to evaluate the immunohistochemical distribution of vimentin in the temporomandibular joint (TMJ) and to compare it with the control specimens. Immunohistochemical distribution in the disc and synovial membrane in 30 human TMJ (internal derangement of TMJ, n = 20; and control, n = 10) was studied immunohistologically using paraffin-embedded tissue and specific anti-human vimentin monoclonal antibody. Vimentin expression was distributed in chondrocyte-like cells, synovial cells and endothelial cells. There was an obvious distinction of vimentin immunoreactivity between the control specimens and internal derangement cases, in the posterior and/or anterior loose connective tissues. In particular, intensive vimentin expression was detected in the hypertrophic synovial membrane of internal derangement cases. The findings of the present study suggest that vimentin might be an important marker of pathological hypertrophy of the synovial membrane and/or connective tissue with internal derangement of TMJ.     

Expression of osteoprotegerin in synovial tissue and degradation of articular cartilage: comparison with arthroscopic findings of temporomandibular joint disorders

OBJECTIVE: The aim of this study was to investigate the correlations among the expression of osteoprotegerin (OPG) in synovial tissue and the degree of synovitis, the degeneration of articular cartilage, and the adhesions in patients with internal derangement and osteoarthritis of the temporomandibular joint (TMJ).Study design The expression of OPG, which was detected immunohistochemically, and the degree of arthroscopy of 31 patients with internal derangement and osteoarthritis of the TMJ were assessed and the correlations between them were analyzed statistically. RESULTS: OPG was expressed in the cytoplasm of the endothelial cells, synovial lining cells, and fibroblast cells. TMJs with osteoarthritis had a higher degree of articular cartilage degeneration than did TMJs with internal derangement. There was a correlation between the expression of OPG in the endothelial cells and the degree of the articular cartilage degeneration (P <.01). CONCLUSION: The expression of OPG might be associated with the development of degenerative changes of articular cartilage.     

Relation between the expression of vascular endothelial growth factor in synovial tissues and the extent of joint effusion seen on magnetic resonance imaging in patients with internal derangement of the temporomandibular joint

The aim of this study is to elucidate the relation between the expression of vascular endothelial growth factor (VEGF) in synovial tissues and the extent of joint effusion seen on magnetic resonance imaging (MRI) in patients with internal derangement of the temporomandibular joint (TMJ). Using an immunohistochemical technique, we examined specimens of synovial tissues from 41 joints in 40 patients with internal derangement. Specimens from 36 of the 41 joints stained for VEGF. There was a significant correlation between the percentage of the VEGF-stained cells and the grade of joint effusion seen on MRI (P=0.0002, r=0.62). The correlation between the two was also significant on multiple logistic regression analysis (P=0.003, odds ratio=1.75). These results suggest that VEGF may have an important role in the genesis of joint effusion.     

Immunohistochemical localization of cyclooxygenase-1 and -2 in synovial tissues from patients with internal derangement or osteoarthritis of the temporomandibular joint

This study examined the immunohistochemical expression and localization of cyclooxygenase-1 and -2 (COX-1 and COX-2) in synovial tissues from patients with internal derangement (ID) or osteoarthritis (OA) of the temporomandibular joint (TMJ). Synovial tissues from patients with condylar fractures of the mandible were studied as control. Synovial tissues from 13 TMJs of 10 patients with ID or OA and from 5 TMJs of 4 patients with fractures were examined for COX-1 and COX-2 expression by immunohistochemical staining using two monoclonal antibodies. In addition, whether the COX-2 expression grade correlated with the synovitis score and clinical findings was assessed. COX-2 was expressed in the synovial lining, infiltrating mononuclear cells, fibroblast-like cells, and blood vessels, including CD31-positive endothelial cells, in the synovium of patients with ID or OA. Expression levels of COX-1 in synovial lining cells and endothelial cells were similar in the specimens obtained from the patients with ID or OA and those obtained from the controls. The expression of COX-2 positively correlated with arthroscopic findings of synovitis (p = 0.55, P = 0.023) and with joint pain (p = 0.56, P = 0.021). These results suggest that up-regulation of COX-2 in synovium may play a part in the pathogenesis of synovitis in patients with ID or OA of the TMJ.     

Bradykinin expression in synovial tissues and synovial fluids obtained from patients with internal derangement of the temporomandibular joint

Bradykinin has been implicated in the pathogenesis of inflammatory arthritis by virtue of the potent pro-inflammatory properties. The purpose of this study is to investigate the expression of bradykinin in patients with internal derangement of the temporomandibular joint (TMJ). We examined 33 TMJ synovial biopsy specimens from 31 patients with internal derangement of the TMJ by an immunohistochemical technique using specific antibodies. We also determined the concentration of bradykinin in 20 synovial fluids from 18 patients with TMJ internal derangement by enzyme-linked immunosorbent assay. These data were compared with those of the control subjects. Bradykinin was predominantly localized in the synovial lining cell layer of TMJ samples obtained from patients with TMJ internal derangement. Bradykinin was also detected in 19 patients' TMJ synovial fluids and the average of bradykinin concentration in the synovial fluids of patients was higher than that of the healthy controls. Although a statistically significant correlation was not observed, these findings support the hypothesis that bradykinin may also be involved in the pathogenesis of TMJ pain and synovitis.     

Vascular endothelial growth factor concentrations in synovial fluids of patients with symptomatic internal derangement of the temporomandibular joint

BACKGROUND: Vascular endothelial growth factor (VEGF) is an inducer of angiogenesis and permeability of small blood vessels. We determined the concentrations of VEGF in synovial fluid of patients with symptomatic internal derangement of the temporomandibular joint (TMJ). METHODS: Diluted synovial fluid was collected by a pumping procedure from 22 TMJs of patients with internal derangement and 10 control TMJs. VEGF concentration was determined by an enzyme-linked immunosorbent assay. RESULTS: The VEGF was detected in 14 of the 22 joints (64%) of patients with internal derangement, at a mean concentration of 67 pg/ml, but in only one control joint (12.5 pg/ml) (P = 0.004 for the difference in concentration). There was a significant correlation between VEGF concentration and total protein concentration in the synovial fluid (P = 0.002). CONCLUSIONS: The increased concentration of VEGF in patients with symptomatic internal derangement suggests that this growth factor may be involved in the pathogenesis of this condition.     

Co-expression of interleukin-1β and tumor necrosis factor α in synovial tissues and synovial fluids of temporomandibular joint with internal derangement: comparision with histological grading of synovial inflammation

BACKGROUND: It has been clarified that interleukin-1 (IL-1)beta and tumor necrosis factor (TNF)alpha play an important role in pathogenesis of various joint disease. The purpose of this study was to investigate the cellular source of IL-1beta and TNFalpha in temporomandibular joint (TMJ), and to analyze the relation between the expression of these cytokines and the intensity of TMJ synovial inflammation. METHODS: We examined 33 synovial biopsy specimens from patients with internal derangement of the TMJ by an immunohistochemical technique using specific antibodies to IL-1beta and TNFalpha. We also studied 20 synovial fluids from the patients by enzyme-linked immunosorbent assay method. These data are compared with histological grading of synovial inflammation by Gynther's system. RESULTS: Both IL-1beta and TNFalpha were predominantly localized in the synovial lining cell layer and the blood vessels of synovial biopsy specimens obtained from patients with TMJ internal derangement. A statistically significant correlation was found between the intensity of IL-1beta expression and that of TNFalpha. Additionally, the intensity of TNFalpha expression was statistically correlated with histological grading by Gynther's system. CONCLUSION: These results supported that IL-1beta and TNFalpha may be involved in the occurrence of TMJ internal derangement and that they coordinately play an role in pathogenesis of TMJ internal derangement.     

Bradykinin Expression in Synovial Tissues and Synovial Fluids Obtained from Patients with Internal Derangement of the Temporomandibular Joint

Bradykinin has been implicated in the pathogenesis of inflammatory arthritis by virtue of the potent pro-inflammatory properties. The purpose of this study is to investigate the expression of bradykinin in patients with internal derangement of the temporomandibular joint (TMJ). We examined 33 TMJ synovial biopsy specimens from 31 patients with internal derangement of the TMJ by an immunohistochemical technique using specific antibodies. We also determined the concentration of bradykinin in 20 synovial fluids from 18 patients with TMJ internal derangement by enzyme-linked immunosorbent assay. These data were compared with those of the control subjects. Bradykinin was predominantly localized in the synovial lining cell layer of TMJ samples obtained from patients with TMJ internal derangement. Bradykinin was also detected in 19 patients' TMJ synovial fluids and the average of bradykinin concentration in the synovial fluids of patients was higher than that of the healthy controls. Although a statistically significant correlation was not observed, these findings support the hypothesis that bradykinin may also be involved in the pathogenesis of TMJ pain and synovitis.