Extracellular matrix protein composition corresponds to degenerative changes in disc displacement of the...

To investigate changes to the composition of a panel of extracellular matrix (ECM) proteins in the temporomandibular joint (TMJ) posterior disc attachment in relation to the diagnoses disc displacement with/without reduction (DDwR, DDwoR).

Patients scheduled for arthroscopy or open joint surgery due to DDwR or DDwoR were eligible for inclusion. During surgery biopsies of the posterior disc attachment were harvested. Proteins were extracted from the biopsies and screened using multiplex bead analysis for 23 different ECM proteins. Patients with DDwR served as controls to DDwoR. The variables gender, age, symptom duration, previous trauma, and Wilkes criteria were assessed in relation to the protein concentrations with a quantile regression model. Significance was set at p < 0.05.

DDwoR patients had smaller preoperative mouth opening capacity (p < 0.001) and shorter symptom duration (p = 0.007) compared to DDwR. Patients with a sudden onset of DDwoR more often had trauma to the jaws as an inciting event compared to delayed onset DDwoR (p = 0.014). In the adjusted analyses, ADAMTS13 (p = 0.000), aggrecan (p = 0.012), collagen IVα1 (p = 0.001), Lumican (p = 0.008), MMP-7 (p = 0.000), MMP-10 (p = 0.043), NCAM-1 (p = 0.006), Tenascin C (p = 0.030), TIMP-2 (p = 0.000), and TIMP-3 (p = 0.027) had significantly higher concentrations in DDwoR. MMP-9 (p = 0.019) and syndecan-4 (p = 0.002) demonstrated a positive strong correlation to female gender. A higher Wilkes criteria corresponded to a higher protein composition similarly to how protein composition increased in DDwoR compared to DDwR.

ECM protein composition changes with TMJ diagnoses and Wilkes criteria suggesting degenerative changes as a main factor. Gender seems to marginally affect the ECM.