Anna Appelgren

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.

Measurement of joint aspirate dilution by a spectrophotometer capillary tube system.

The amount of synovial fluid in small joints which is available for analysis of endogenous compounds is usually very limited and saline washings are therefore commonly required. However, since the washing fluid is not fully recovered and, furthermore, dilutes the synovial fluid in the joint aspirate, the true synovial fluid concentration of a particular substance is unknown. In the present study we validate the use of vitamin B12 (hydroxocobalamin, 1 mg ml-1) as an internal standard to determine this dilution, since its strong red colour lends itself to spectroscopic measurement by a capillary tube system requiring only 3 microliter per sample. The absorbance of different dilutions of the stock solutions (25, 33 and 50% vitamin B12 in saline) by saline, plasma and hyaluronan was measured in order to establish the optimal wavelength, the lower limit of detection and the interference by plasma or hyaluronan in the absorbance. Furthermore, the interaction of vitamin B12 in the analyses of interleukin-1 beta, serotonin and glucose was investigated. The optimal wavelength was found to be 350 nm and the limit of detection 0.5-0.9% dilution of the vitamin B12 solution. Hyaluronan or plasma did not influence the absorbance measurements and the minute interaction of vitamin B12 in the photometric measurements could be compensated for.

The effect on joint fluid concentration of neuropeptide Y by intra-articular injection of glucocorticoid in temporomandibular joint arthritis.

Twenty-two patients (29 joints) with temporomandibular joint (TMJ) arthritis of specific or unspecific nature were given one intra-articular glucocorticoid (GC) injection. The effect on subjective symptoms and clinical signs in the craniomandibular system and on joint aspirate concentration of neuropeptide Y-like immunoreactivity (NPY-LI) was evaluated at follow-up visits 2-3 or 4-6 weeks after treatment. In the patients with specific inflammatory joint disease the treatment resulted in an improvement of symptoms and clinical signs and in a reduction in the TMJ level of NPY-LI 2-3 weeks after treatment. In the patients with unspecific inflammatory joint disease there was also an improvement in the clinical variables and a reduction in the NPY-LI level after 2-3 weeks, but not on a statistically significant level. The results of this study show that intra-articular GC treatment causes a short-term decrease of the TMJ fluid level of NPY-LI in patients with specific inflammatory joint disease, while symptoms and signs improve.

A clinical study: Relation between the intra-articular temperature of the temporomandibular joint and the presence of neuropeptide Y-like immunoreactivity in the joint fluid

Arthritic temporomandibular joints were examined for the joint fluid content of neuropeptide Y-like immunoreactivity (NPY-LI) and the intra-articular temperature at two separate sessions. Sixteen patients (23 joints) with rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, and unspecific polyarthritis or monarthritis were investigated in this study. The intraarticular temperature ranged between 35.6 and 37.5 °C, The concentration of NPY-LI ranged between 72.1 and 4466.0 pmol/1 and was above the normal plasma level in all patients. The intra-articular temperature was negatively correlated with the joint fluid concentration of NPY-LI. Moreover, patients with low intra-articular temperature and high concentration of NPY-LI had a shorter duration of TMJ symptoms than those with high intra-articular temperature and low concentration of NPY-LI.

Pain, tenderness, mandibular mobility, and anterior open bite in relation to radiographic erosions in temporomandibular joint disease

The relationship between radiographic changes and clinical signs and symptoms of the temporomandibular joint (TMJ) was investigated in 39 patients with joint diseases. Radiographic erosions were found in 33% of the TMJ joints, and overall frequency of radiographic changes including remodeling was 47%. Fifty-four percent of the patients had an anterior open bite (AOB). The AOB showed statistically significant correlation to the extension of erosion of the TMJ. Pain expressed by means of a visual analog scale, tenderness to palpation of the TMJ, and pressure pain threshold showed no significant correlation to erosion, but mandibular mobility showed significant negative correlation to erosive changes. In conclusion, AOB is correlated with erosive radiographic changes in this patient group. However, the degree of local pain and tenderness showed no correlation to radiographic changes.

Relation between intra-articular temperature of the arthritic temporomandibular joint and presence of calcitonin gene-related peptide in the joint fluid: A clinical study

Arthritic temporomandibular joints were investigated for intra-articular temperature and joint fluid content of calcitonin gene-related peptide. Eleven patients (16 joints) with rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, or chronic unspecific polyarthritis or monarthritis participated in the study. The intra-articular temperature varied between 35.5 and 37.5 degrees C, with a mean of 36.5 degrees C. The concentration of calcitonin gene-related peptide varied between 7.5 and 749.0 pmol/l, with a mean of 108.6 pmol/l. There was a positive correlation between the intra-articular temperature and the joint fluid concentration of calcitonin gene-related peptide. The plasma level of the peptide was on an average 5% of the joint fluid level.