Background
Symptomatic disc displacement (DD) of the temporomandibular joint (TMJ) may cause pain and limited mouth opening. The aetiopathogenesis is obscure and probably complex, which makes the diagnostic classification crude and mainly based on clinical criteria rather than disease mechanisms, and tissue characteristics.
Objectives
The study aim was to characterise and quantify synovial tissue in DD, where specific cytokine patterns might serve as potential biomarkers.
Methods
An observational cohort study was performed harvesting synovial tissue from 63 patients: 44 with DD without reduction (DDwoR) and 19 with DD with reduction (DDwR). DDwoR was subdivided depending on type of onset (sudden, n = 17; delayed, n = 27), and DDwR served as the control group. Proteins were extracted from tissue samples and investigated in a multi‐analytic profiling system.
Results
DDwoR patients had significantly higher concentrations in 12 out of 28 analysed cytokines compared to DDwR. In the same statistical model, significantly lower concentrations of interferon gamma‐induced protein (IP) 10, osteoprotegerin (OPG) and RANTES were detected in DDwoR patients. Women showed significantly higher concentrations of epidermal growth factor and interleukin (IL) 1ra compared to men. DDwoR with sudden onset had significant higher concentrations of bone morphogenetic protein 4, eotaxin and IL‐8 compared to DDwoR with delayed onset.
Conclusions
Characterising the biomarker panel for TMJ conditions may serve as suggestible targets for disease classification and novel treatment options. The significantly lower concentrations of IP‐10, OPG and RANTES could be proposed as putative markers for the separation of the studied conditions to other TMJ diseases.
Our knowledge of synovial tissues in patients that are scheduled for surgery as a result of temporomandibular joint (TMJ) disorders is limited. Characterising the protein profile, as well as mapping clinical preoperative variables, might increase our understanding of pathogenesis and forecast surgical outcome. A cohort of 100 patients with either disc displacement, osteoarthritis, or chronic inflammatory arthritis (CIA) was prospectively investigated for a set of preoperative clinical variables. During surgery, a synovial tissue biopsy was sampled and analysed via multi-analytic profiling. The surgical outcome was classified according to a predefined set of outcome criteria six months postoperatively. Higher concentrations of interleukin 8 (p = 0.049), matrix metalloproteinase 7 (p = 0.038), lumican (p = 0.037), and tissue inhibitor of metalloproteinase 2 (p = 0.015) were significantly related to an inferior surgical outcome. Several other proteins, which were not described earlier in the TMJ synovia, were detected but not related to surgical outcome. Bilateral masticatory muscle palpation pain had strong association to a poor outcome that was related to the diagnoses disc displacement and osteoarthritis. CIA and the patient-reported variable TMJ disability might be related to an unfavourable outcome according to the multivariate model. These findings of surgical predictors show potential in aiding clinical decision-making and they might enhance the understanding of aetiopathogenesis in TMJ disorders.
Temporomandibular joint (TMJ) disease classification and subsequent treatment selection are highly debated subjects within dentistry and medicine. Several suggestions for diagnostic classification and treatment algorithms have been proposed thus far without achieving a clear gold standard. A universally accepted diagnostic classification is essential for therapeutic decision-making as well as a prerequisite for prognostic evaluation and is necessary for achieving research results that are reproducible, comparable, relevant, and applicable in the clinical setting. Often, problems of the TMJ are viewed as mere symptoms or as a syndrome-like group of conditions, without clear demarcation, impeding individualized treatment planning. A Scandinavian group of experienced TMJ surgeons participated in an iterative, structured group discussion process in accordance with the Delphi method, aiming to produce recommendations for a standardized patient clinical evaluation in relation to TMJ dysfunction. Guided by this standardized evaluation, a disease-focused and simplified diagnostic classification scheme is herein suggested.
Background
Synovial tissue is known to be the origin of inflammation in joint disease. Despite this, synovial fluid is the main biological specimen of choice in temporomandibular joint (TMJ) inflammation and pathology biomarker research. No comparison of TMJ protein content between synovial fluid and synovial tissue has been made.
Objectives
The aim of this study was to investigate whether cytokine concentrations in synovial fluid can be related to cytokine concentrations in synovial tissue and to analyse correlation of clinical parameters reflecting local inflammation to cytokine concentrations.
Methods
Synovial tissue and fluid samples were obtained during the same surgical procedure from a cohort of 101 patients with TMJ disorders. Interleukin (IL) 1β, IL‐6, IL‐8, IL‐10 and tumour necrosis factor α (TNF‐α) were analysed in the samples and an intraindividual correlation made. Various patient‐specific factors related to TMJ inflammation were associated with the cytokine concentrations in synovial fluid and tissue.
Results
No correlation between cytokine concentration in synovial fluid and synovial tissue was found, except for IL‐8 (ρ = .284, p = .024). Synovial tissue cytokines correlated strongly to inflammation‐related factors: diagnosis (IL‐1β, p = .001; TNF‐α, p = .000; IL‐10, p = .000), TMJ palpation pain (IL‐1β, p = .024; TNF‐α, p = .025), synovitis score (IL‐1β, p = .015) and subjective TMJ pain (TNF‐α, p = .016). Synovial fluid cytokines showed no significant relations to inflammation.
Conclusions
The investigated cytokine concentrations showed weak correlations between synovial fluid and synovial tissue, besides IL‐8. Synovial tissue appeared to reflect inflammation to a higher extent than synovial fluid. Thus, suggesting that synovial tissue research should complement synovial fluid in future explorations of TMJ pathology and inflammation.
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