Prostaglandin E2 in temporomandibular joint synovial fluid and its relation to pain and inflammatory disorders.

PURPOSE: The aim of this study was to investigate temporomandibular joint (TMJ) synovial fluid (SF) levels of prostaglandin E2 and its relation to general inflammatory activity and its influence on specific TMJ pain in patients with inflammatory TMJ disorders. PATIENTS AND METHODS: The study comprised 24 patients (30 joints) with inflammatory TMJ disorders and 4 healthy persons (6 joints). TMJ pain at rest, tenderness to palpation of the TMJ, and TMJ pressure pain threshold, as well as pain during joint movements (PM), were assessed. PGE2 levels were analyzed in synovial fluid samples (SF-PGE2) and blood plasma (P-PGE2). The erythrocyte sedimentation rate (B-ESR) as well as the serum levels of C-reactive protein (S-CRP) and antinuclear antibodies were determined. RESULTS: PGE2 was undetectable in the plasma and in the TMJ SF of the healthy persons. In the patients, PGE2 was detectable in 20 of the 30 (67%) SF samples. SF-PGE2 was significantly and positively correlated to PM in the patients. There were significant correlations between P-PGE2 and B-ESR as well as the S-CRP. CONCLUSIONS: This study shows that the synovial fluid in patients with TMJ inflammatory disorders frequently has a detectable level of PGE2 that is related to TMJ allodynia. The plasma levels of PGE2 seem to be related to the general inflammatory activity in these patients.

Cytokines in temporomandibular joint arthritis.

As the article in the current issue by Shinoda and colleagues shows, during the last two decades, there has been a dramatic increase in the understanding of basic biology behind chronic temporomandibular joint (TMJ) pain, inflammation and destruction. The involvement and contribution of cytokines to TMJ pain and inflammation must now be considered as established, evident and fundamental. Based on the present knowledge, it is now possible to design and investigate novel therapeutic strategies. These new and very encouraging approaches include manipulation of cytokine function, immune reactivity and the behaviour of inflammatory cells while maintaining the integrity of the affected tissue.

Synovial fluid sampling from the temporomandibular joint: sample quality criteria and levels of interleukin-1 beta and serotonin.

The aims of this study were to compare two sets of quality criteria (SQC A and B) with respect to synovial fluid (SF) sampling and to present temporomandibular joint (TMJ) SF levels of IL-1 beta and 5-HT. The study comprised 310 TMJ SF samples from 12 healthy individuals (HI) and 59 patients with TMJ inflammatory disorders. Ten HI and 37 patients were selected for investigation of TMJ SF levels and samples were obtained by a push-and-pull method with quantification by vitamin B12. The SQC comprised aspirate weight (AW), dilution factor (DF), blood contamination and hemolysis. IL-1 beta and 5-HT levels did not differ between the samples that satisfied SQC A or B. The proportion of samples that satisfied SQC A was higher than for SQC B. Patients with polyarthritides had significantly higher TMJ SF concentrations of 5-HT and IL-1 beta than HL. In conclusion, there is a recovery of TMJ SF of 0.1-0.2 g with the method used and the criteria set with the highest success rate do not differ from the other one with respect to SF levels of IL-1 beta and 5-HT. This set of sample quality criteria comprised no hemolysis, no or only minor blood contamination, AW > 0.5 g and DF < 0.98. The higher SF levels in the diseased TMJ (polyarthritides) compared to the healthy joint with respect to 5-HT and IL-1 beta is of clinical diagnostic relevance and the presence of 5-HT or IL-1 beta in TMJ SF seems to indicate a pathological joint condition probably of an inflammatory nature.

Interleukin-1beta in synovial fluid from the arthritic temporomandibular joint and its relation to pain, mobility, and anterior open bite.

PURPOSE: The purpose of this study was to investigate whether interleukin-1beta in synovial fluid or blood plasma is involved in the development of pain or hyperalgesia of the temporomandibular joint (TMJ), as well as reduced mandibular mobility and anterior open bite. PATIENTS AND METHODS: Twenty-nine patients with TMJ arthritis and seven healthy subjects were studied. VAS measurement of TMJ tenderness on palpation of the TMJ (TDP), TMJ pressure pain threshold and tolerance level (PPTL), mandibular mobility, pain during joint movements, and degree of anterior open bite (AOB) were assessed. IL-1beta levels were analyzed in TMJ synovial fluid (SF-IL-1beta) and blood samples and correlated with the preceding factors. RESULTS: SF-IL-1beta showed significant positive correlations with VAS measurement of pain, TDP, and AOB and a negative correlation with PPTL. CONCLUSIONS: This study indicates that IL-1beta in the synovial fluid is associated with pain and hyperalgesia in the TMJ region as well as an anterior open bite. Concerning the latter condition, IL-1beta seems to be a warning signal of tissue destruction.

Interleukin-1beta in plasma and synovial fluid in relation to radiographic changes in arthritic temporomandibular joints.

The aim of this study was to investigate the level of the cytokine IL-1beta in plasma and temporomandibular joint (TMJ) synovial fluid of patients with arthropathies, and to study the relation between IL-1beta levels of synovial fluid and plasma as well as radiographic changes of the TMJ. 31 patients with general disease, 14 with rheumatoid arthritis (RA) and 17 with various arthritides were included in the study. Synovial fluid and blood samples were collected, and an individualized tomography of the TMJ was performed. Detectable levels of IL-1beta were found in 5 out of 39 synovial fluids and in 10 out of 27 plasma samples. The presence of IL-1beta in both plasma and synovial fluid was more frequent in RA patients than in the non-RA group. The extension of radiographic erosion was significantly greater in joints with IL-1beta than in those without. Both the extension of erosion and grade of radiographic changes of the TMJ were greater in patients with detectable IL-1beta level of plasma than in patients without. Our study indicates that presence of IL-1beta in plasma and synovial fluid is related to radiographic changes of the TMJ.

Pain and synovial fluid concentration of serotonin in arthritic temporomandibular joints.

The aim of this study was to investigate the relation between serotonin in the synovial fluid (SF-5-HT) and pain of arthritic temporomandibular joints (TMJ). The study comprised 1 male and 10 female patients (22 TM joints) with bilateral TMJ pain or tenderness and a mean age of 42 years. The patients were studied regarding pain from the TMJ at rest and during mandibular movements as well as regarding pressure pain thresholds and tolerance levels over the TMJ. TMJ samples, obtained by saline washing of the joint, and blood serum samples were taken for measurement of the 5-HT content. There was a positive correlation between SF-5-HT and pain in the TMJ upon movement. Maximum voluntary mouth opening ability was negatively correlated to SF-5-HT. In conclusion, the results of this study indicate that 5-HT in the TMJ synovial fluid is related to pain perceived upon movement of the joint and to decreased mandibular mobility.

A model for the study of experimentally induced temporomandibular arthritis in rats: the effect of human recombinant interleukin-1 alpha on neuropeptide-like immunoreactivity.

To study the interaction between human recombinant interleukin-1 alpha and the nervous system, substance P-, neurokinin A-, calcitonin gene-related peptide-, and neuropeptide Y-like immunoreactivity in the cerebrospinal fluid, plasma, and temporomandibular joint (TMJ) perfusates of rats during acute experimental monarthritis were examined. The right TMJs of the experimental rats were injected with 0.01 mL of human recombinant interleukin-1 alpha. The right TMJs of control rats were injected with 0.01 mL of saline. Cerebrospinal fluid, plasma, and perfusates from the right TMJs were obtained at 2, 6, and 24 hours following injection, and neuropeptide-like immunoreactivity was analyzed by specific radioimmunoassays. Values of neuropeptide-like immunoreactivity for the experimental rats were compared with those of the control rats. In the experimental group, substance P-, neurokinin A-, and calcitonin gene-related peptide-like immunoreactivities were increased in cerebrospinal fluid compared to those of the control group. In plasma, no changes in neuropeptide-like immunoreactivities rose significantly in the TMJ perfusates. Most pronounced changes in neuropeptide Y-like immunoreactivity occurred intra-articularly in the TMJ perfusates. The results indicate that the contribution of the nervous system to human recombinant interleukin-1 alpha-induced monarthritis is most pronounced in the affected joint.

Determination of temporomandibular joint fluid concentrations using vitamin B12 as an internal standard.

The aim of the investigation was to test the reproducibility and accuracy of a new method to measure temporomandibular joint (TMJ) fluid concentrations of various substances by saline washing, using exogenous B12 as a marker. An in vitro test was first performed with glucose as a test substance. The difference between a B12-calculated and known standard concentration of glucose was very small. Saline washing of the TMJ was performed on 13 patients having signs of TMJ arthritis, and the aspirates obtained were analyzed for neuropeptide Y-like immunoreactivity (NPY-LI) and interleukin-1 beta (IL-1 beta). Vitamin B12 was mixed with the saline immediately before injection, and a sample of the aspirate was later compared photometrically with the injection solution. There were positive correlations between saline aspirate and joint fluid concentrations for NPY-LI and IL-1 beta, and the correlations were stronger for saline aspirates with high joint fluid content. This study shows that the method is reliable for measurement of joint fluid concentrations of various substances, such as NPY-LI and IL-1 beta.

Co-variation of neuropeptide Y, calcitonin gene-related peptide, substance P and neurokinin A in joint fluid from patients with temporomandibular joint arthritis.

Forty-one patients (37 female and four male) with signs and symptoms of temporomandibular joint arthritis, were separated into two diagnostic groups (group I: inflammatory; group II: degenerative/non-specific joint disease). They were examined clinically, fluid was aspirated from the joint with saline and venous blood samples were collected at the same time. The joint fluid and plasma samples were analysed for neuropeptide-like immunoreactivity, i.e. neuropeptide Y (NPY-LI), calcitonin gene-related peptide (CGRP-LI), substance P (SP-LI) and neurokinin A (NKA-LI), using competitive radioimmunoassays. The aim was to investigate any co-variation of the peptides in the joint fluid and plasma. In group I, the median values of peptide concentrations in joint fluid were SP-LI = 129, CGRP-LI = 75, NKA-LI = 36 and NPY-LI = 676 pmol/l and in group II, SP-LI = 52, CGRP-LI = 64, NKA-LI = 45 and NPY-LI = 318 pmol/l. There were no significant differences between the groups for peptide concentrations. In group I, all the neuropeptides were strongly correlated. In group II, SP-LI and NKA-LI were strongly correlated while CGRP-LI was weakly correlated with NPY-LI and NKA-LI. Multiple step-wise regression analysis showed that most of the variation in NPY-LI, CGRP-LI and SP-LI in group I was explained by NKA-LI, but the regression did not reach statistical significance in group II.