Potential biomarkers of temporomandibular joint disorders

The purpose of this study was to identify protein markers present in subjects with temporomandibular joint disorders (TMDs) and clicking compared with the levels in controls.

This was a pilot case-control study, and we report the preliminary results. Samples of joint aspirate collected from patients with TMDs and controls who had undergone surgery for a problem other than TMDs were analyzed using isobaric tags for relative and absolute quantitation (iTRAQ) and biotin-labeled-based protein arrays. The data obtained from these techniques were used to identify the proteins of interest, which were then quantitated using enzyme-linked immunosorbent assay (ELISA). The patient samples studied included joint aspirate collected clinically from the controls and patients and included samples from both the right and the left sides of each patient with a TMD.

The 8 TMJ aspirate samples from 6 subjects included 5 aspirate samples from 4 patients and 3 from 2 controls. The greatest standardized protein concentration of endocrine gland-derived vascular endothelial growth factor/prokineticin-1 (EG-VEGF/PK1) and D6 was found in both joints of the controls compared with the levels from the joints of the patients. With 1 exception, the standardized protein concentration was significantly lower in the patients than in the controls. The lower levels of EG-VEGF/PK1 and D6 in the patients compared with the controls suggest that these cytokines might be possible biomarkers for TMDs.

In the present pilot study, greater levels of EG-VEGF/PK1 and D6 were found in the controls than in the patients with TMDs. Proteomic analysis of the proteins present in the diseased joints compared with those in the controls might help to identify proteins present when pain or degeneration of the joint occurs. The proteomic information might be useful in the development of future therapies.