Immunohistochemical localization of inducible nitric oxide synthase in synovial tissue of human temporomandibular joints with internal derangement

The expression and distribution of inducible nitric oxide synthase (iNOS) was examined in 12 samples of human temporomandibular joint (TMJ) with internal derangement (ID) and four control specimens. In the diseased joints, strong or definite iNOS reactivity was expressed in synovial lining and endothelial cells; weaker activity was present in synovial fibroblasts. In contrast, although there was weak expression of iNOS in synovial fibroblasts and endothelial cells in the two control specimens, there was no iNOS staining in the synovial lining cell layers. This original report that iNOS is expressed in the synovial tissue of the temporomandibular joint indicates that nitric oxide is produced locally at least in the synovial lining in these joints when affected by internal derangement.     

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.     

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 expression of transforming growth factor beta (TGF-beta) in the synovial membrane of human temporomandibular joint with internal derangement: a comparison with tenascin expression

We examined the expression of the transforming growth factor beta (TGF-beta) in 28 human temporomandibular joint (TMJ) samples (internal derangement of TMJ and control specimens) by an immunohistological method using paraffin-embedded tissues and a polyclonal antibody specific to human TGF-beta. The resulting reaction of TGF-beta expression divided into three types as follows. The first type, around the fibrocyte and in the lacunae of chondrocytes in the disc. The second type, at the stroma of the mildly hypertrophic synovial membrane and severely hypertrophic synovial membrane. The first type was observed in all the cases including the control cases. The second type showed only in the internal derangement of TMJ, and its expression pattern resembled that of tenascin (TN) within the stroma of hypertrophic synovial membranes. In conclusion, TGF-beta and TN were distributed in the affected synovial membrane of TMJ with internal derangement. These findings suggested that TGF-beta and TN might have a close relationship with synovitis, followed by tissue repair.     

Up-regulation of vascular endothelial growth factor in synovial fibroblasts from human temporomandibular joint by hypoxia

INTRODUCTION: Enhanced expression of vascular endothelial growth factor (VEGF) has been described in patients with internal derangement (ID). Herein, we examined the expression of VEGF in synovial fibroblasts from temporomandibular joint (TMJ) under hypoxia and investigated the regulation of hypoxia-inducible factor-1alpha (HIF-1alpha) involved in the expression of VEGF. METHODS: Synovial fibroblasts were prepared from human TMJ. These cells were incubated under hypoxia or normoxia for the indicated time periods. VEGF levels in cultured supernatant were measured by an ELISA. VEGF mRNA isoforms and stability were assessed using RT-PCR and Northern blot analysis respectively. HIF-1alpha accumulation was evaluated by Western blotting and immunofluorescence. RESULTS: VEGF were significantly induced by hypoxia in synovial fibroblasts. In response to hypoxia, VEGF121 and VEGF165 mRNA were both remarkably increased, while there was no change in VEGF mRNA stability. The accumulation and nuclear translocation of HIF-1alpha occurred under hypoxia. CONCLUSIONS: Hypoxia may mainly induce the expression of VEGF121 and VEGF165 in synovial fibroblasts to promote inflamed angiogenesis of TMJ. HIF-1alpha, which is clearly activated in response to hypoxia, may control the expression of VEGF in synovial fibroblasts from TMJ.     

Angiogenesis in the human temporomandibular joint studied by immunohistochemistry for CD34 antigen

The CD34 antigen is a sensitive marker of vascular endothelium and angiogenesis. Thus, we examined the expression of CD34 in 20 human temporomandibular joint (TMJ) samples with internal derangement and in 10 control specimens by an immunohistological technique using paraffin-embedded tissue and specific anti-human CD34 monoclonal antibody. In the control specimens, CD34 was observed sporadically within the TMJ discs. On the other hand, in the internal derangement specimens, CD34 was found frequently in the walls of blood capillaries within the TMJ discs. In the synovial membrane, CD34 was detected frequently in the walls of many blood capillaries in both the controls and the internal derangement specimens. Indeed, CD34 expression in internal derangement specimens was more intense than in control specimens. In the posterior loose connective tissue of the bilaminar zone, and in the anterior loose connective tissue between the upper and lower lamellae of the anterior capsular wall, CD34 was detected in abundance in the walls of blood capillaries both of the controls and the internal derangement specimens. Generally, CD34 was found rarely in the walls of large blood vessels. The presence of CD34 is suggested to be correlated with the process of angiogenesis induced by 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.     

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 cyclooxygenase-2 in human temporomandibular joint samples: an immunohistochemical study

The aim of this investigation was to evaluate the immunohistochemical expression of cyclooxygenase-2 (COX-2) in the temporomandibular joint (TMJ) and to compare it with that control specimens. Expression of COX-2 in the TMJ disc and the synovial membrane in 26 human TMJ samples (internal derangement of TMJ; n=16, and control; n=10) was measured by an immunohistological technique using paraffin-embedded tissue and specific antihuman COX-2 polyclonal antibody. There were obvious distinction of COX-2 immunoreactivity between the control specimens and internal derangement cases, in the region of posterior and/or anterior loose connective tissues. In particular, intensive COX-2 expression was detected in the synovial membrane of internal derangement cases. The findings of the present study suggest that COX-2 might be an important mechanism regulating inflammation in the synovial membrane with internal derangement of 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.     

The localization of matrix metalloproteinase-3 and tenascin in synovial membrane of the temporomandibular joint with internal derangement

OBJECTIVES: The aim of this investigation was to study the immunohistochemical localization of MMP-3 and tenascin in the temporomandibular joint and to compare it with control specimens. MATERIALS AND METHODS: Localizations of matrix metalloproteinase-3 (MMP-3) and tenascin in the temporomandibular joint disc and the synovial membrane in 26 human temporomandibular joint samples (internal derangement of TMJ; n = 16, and control; n = 10) by an immunohistological method with monoclonal antibodies specific to human MMP-3 and tenascin. RESULTS: MMP-3 was not distributed in control specimens while it was observed in the internal derangement cases. MMP-3 showed two staining profiles: (1) diffuse staining was observed within the stroma of severely deformed disc with osteophyte and/or disc displacement (three of 16 specimens); and (2) the localization was specifically detected on the surface of severely hypertrophic synovial membrane (six of 16 specimens). The latter localization pattern resembled that of the tenascin on the surface of the severely hypertrophic synovial membrane. CONCLUSION: Comparative localization of MMP-3 and tenascin revealed intense staining for both in the synovial membrane presenting inflammation, proliferation and hypertrophy. These findings suggest that tissue repair and remodeling in the temporomandibular joint disc and the inflammatory hypertrophic reaction in the synovial membrane might proceed at the same time.     

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.     

The expression of substance P in human temporomandibular joint samples: an immunohistochemical study

The expression of neuropeptide substance P was examined in 18 human temporomandibular joint (TMJ) samples with internal derangement of the TMJ, and in 10 control specimens. The examination was carried out using an immunohistological technique, using paraffin-embedded tissue and specific anti-human substance P polyclonal antibody. We noted five characteristic distribution patterns of substance P expression: at the nerves' fibre bundles in the connective tissues of the anterior and/or posterior attachment; around the blood vessels in the attachments; at the margin of the TMJ disc and synovial membrane layer; on the surface of hypertrophic synovial membranes with inflammation and proliferation; and around the newly formed capillaries in the TMJ discs. In TMJs with internal derangement associated with severe pain, we found distinct substance P expression in most of the specimens. The expression was particularly intense at the margin of the TMJ disc and synovial membrane layer, on the surface of hypertrophic synovial membranes and around the newly formed capillaries in the TMJ discs. The clinical symptoms of internal derangement of the TMJ are thought to be associated with the degree of synovitis. We conclude that the expression of substance P seems to be closely related to histopathological changes of the human TMJ with internal derangement.     

Analysis of 70Kd heat shock protein expression in patients with internal derangement of the temporomandibular joint

Recent studies have demonstrated that the expression of heat shock protein (HSP) was enhanced under stress in joint diseases, such as rheumatoid arthritis and osteoarthritis. The purpose of this study was to analyze the expression of 70Kd HSP in patients with internal derangement of the temporomandibular joint (TMJ) by immunohistochemical and enzyme-linked immunosorbent assay (ELISA) methods. For immunohistochemistry, 5 extirpated discs and 16 synovial biopsy specimens from patients with TMJ internal derangement and 2 extirpated discs from normal subjects were examined. For ELISA, synovial fluid from 11 patients with TMJ internal derangement and from 6 normal volunteers were investigated. The results showed that the 70Kd HSP staining intensity in chondrocytes around the damaged area of the articular discs from patients with TMJ internal derangement was higher than that in chondrocytes in control specimens. In addition, 70Kd HSP expression in synovial fluid from patients with TMJ internal derangement was slightly higher than that in normal subjects. These findings suggest that elevated 70Kd HSP expression is related to the progression of TMJ internal derangement.     

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.     

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.     

Expression of VEGF-receptors in TMJ synovium of rabbits with experimentally induced internal derangement

Our aim was to evaluate the expression of vascular endothelial growth factor receptors (VEGFRs) in the synovium of the temporomandibular joints (TMJ) of rabbits with experimentally induced internal derangement. Internal derangement was experimentally induced in 52 rabbit TMJ, and established on the right side of TMJ while the left side was used as the control. Each joint and its control was evaluated by magnetic resonance imaging (MRI) and endoscopy. The synovial tissues on both sides were harvested after one, two, three, and four weeks. The expression of VEGFRs mRNA was investigated in the experimental joint and its control using real-time polymerase chain reaction (PCR). Internal derangement was successfully confirmed in 45 of the 52 of the experimental joints (87%) on the right side by MRI and endoscopy. In the first and fourth week, the VEGFR-2 mRNA expression was higher in the experimental joints than in the controls (P = 0.008 and P = 0.02). Meanwhile, the VEGFR-1 mRNA expression was up-regulated in the experimental group compared with the controls during the fourth week (P = 0.02). However, we found no significant differences in VEGFR-3 mRNA expression in the two groups during the first and fourth weeks. During the second and third weeks, the mRNA expression of the three receptors did not differ significantly among the groups. Our data have shown increased expression of VEGFR-1 and VEGFR-2 mRNA in the synovium of rabbit TMJ with internal derangement, which indicates that VEGFR-1 and VEGFR-2 may have important roles in the processes of internal derangement and formation of adhesions.