Björn 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.

Effects of adjuvant on neuropeptide-like immunoreactivity in experimentally induced temporomandibular arthritis in rats

Substance P (SP)-, neurokinin A (NKA)-, calcitonin gene-related peptide (CGRP)- and neuropeptide Y (NPY)-like immunoreactivities (-LI) were examined in cerebrospinal fluid (CSF), plasma and temporomandibular joint (TMJ) perfusates in rats 1 and 12 h after inoculation at the base of the tail (0.05 ml) or injection into the right TMJ (0.01 ml) of heat-killed Mycobacterium butyricum in paraffin oil. In the rats inoculated at the base of the tail (polyarthritic rats), there was a significant increase of CGRP-LI and NKA-LI. The changes in neuropeptide-LI were not as marked in the CSF of rats injected with adjuvant in one TMJ (monoarthritic rats) as in the polyarthritic group. Instead, the most significant changes in the monoarthritic rats were seen in the perfusates of both TMJs. The increases in SP-, NKA-, CGRP- and NPY-LI were significant for both TMJs and more pronounced than in the polyarthritic rats. The results show that inoculation of adjuvant at the base of the tail induces significant changes of neuropeptide-LI predominantly in CSF, whilst an intra-articular injection induces bilateral changes in neuropeptide-LI in joint perfusate. Therefore, two different neural mechanisms may be involved early in adjuvant-induced poly- and monoarthritis.

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 model for experimental induction of acute temporomandibular joint inflammation in rats: Effects of substance P(SP) on neuropeptide-like immunoreactivity

This is a study of neurokinin A (NKA)-, calcitonin gene-related peptide (CGRP)- and neuropeptide Y (NPY)- like immunoreactivity(-LI) in the cerebrospinal fluid (CSF), plasma and perfusates (PF) from the temporomandibular joints (TMJs) of the rat during acute inflammation. Substance P (10(-5) M, 0.01 ml) was injected into the right TMJ of the rat. The TMJs of the control rats, were injected with 0.01 ml saline. CSF, plasma and PF from TMJs were taken at 2, 6 and 24 hrs following injection. The neuropeptide-LI level was analysed by specific radioimmunoassays and compared with control values. Unilateral injection of SP into the rat TMJ resulted in a general increase in the concentration of NKA-, CGRP- and NPY-LI in the TMJ PF at 2, 6 and 24 hrs following injection. In the CSF NKA- and CGRP-LI was increased leaving the NPY-LI unaffected. In general no changes in peptide concentrations were seen in plasma. The results indicate that SP directly or indirectly induces a local release of peptides through an action at sensory and sympathetic neurons.

Effects of capsaicin in temporomandibular joint arthritis in rats

Temporomandibular joint (TMJ) arthritis was induced in female Lewis rats by unilateral injection of a suspension of heat-killed Mycobacterium butyricum in paraffin oil into the TMJ. Control rats received paraffin oil by the same route. Arthritic and control rats were pretreated either with capsaicin or denervation of the mandibular branch of the trigeminal nerve. Tissues were collected for neuropeptide extraction and analysed by radioimmunoassay and reverse-phase high-performance liquid chromatography. In all groups, the levels of substance P-(SP), calcitonin gene-related peptide- (CGRP) and neuropeptide Y- (NPY) like immunoreactivity (LI) were higher in the trigeminal ganglia than in the TMJs. In control rats, capsaicin significantly lowered the levels of SP-LI in the trigeminal ganglia and TMJ, but not CGRP-LI and NPY-LI. In the arthritic rats, capsaicin pretreatment significantly lowered the SP-LI and CGRP-LI in the trigeminal ganglia and TMJ, but not the NPY-LI. In the trigeminal ganglia the unilateral denervation significantly lowered SP-LI in control rats, and in arthritic rats SP-LI and CGRP-LI. On the denervated side of the arthritic TMJ, NPY-LI, SP-LI and CGRP- LI were significantly lowered as compared to the arthritic control rats and to the contralateral side. In this rat model, pretreatment with capsaicin and surgical denervation decreased the neuropeptide content in the trigeminal ganglia and the TMJ. The results clearly demonstrate a close interaction between increased neuropeptide release from sensory and sympathetic neurones after induction of arthritis in the rat.

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.

Low concentrations of inorganic mercury inhibit in vitro autonomic transmission in the presence of albumin

The influence of albumin, 4.5 and 45 g/l, on the effects of Hg2+, 10(-9)-10(-3) M, on the neuromuscular transmission of the isolated guinea-pig ileum and vas deferens was investigated. Hg2+, 10(-9)-10(-6) M, transiently increased the basal tone of the ileum in Tyrode solution without albumin. Albumin, 4.5 g/l, reversed this stimulant effect but enhanced the contractile response to direct muscle stimulation. This contractile response also increased in the vas deferens. Albumin, 45 g/l, obliterated the stimulant effects of Hg2+ on the smooth muscle of the ileum but not of the vas deferens. The effects caused by higher concentrations of Hg2+, 10(-5)-10(-4) M, were only partly inhibited when albumin was present. When neurogenic contractions were elicited in the presence of albumin (45 g/l), Hg2+, 10(-9)-10(-4) M, reduced the contractions in both organs. Consequently, Hg2+ in concentrations presently considered acceptable in blood plasma (10(-9)-10(-8) M) suppressed both cholinergic and adrenergic neuromuscular transmission even in the presence of albumin.