Tumor necrosis factor mediates temporomandibular joint bone tissue resorption in rheumatoid arthritis

Abstract

Objective. To investigate if TNF, IL-1 or their endogenous controls, in relation to ACPA, are associated with radiological signs of ongoing temporomandibular joint (TMJ) bone tissue resorption and disc displacement in RA patients. Methods. Twenty-two consecutive outpatients with TMJ of RA were included. Systemic inflammatory activity was assessed by DAS28. The number of painful regions in the body and ESR, CRP, RF and ACPA were analyzed. TMJ synovial fluid and blood samples were obtained and analyzed for TNF, TNFsRII, IL-1ra, IL-1sRII and ACPA. The ratios between the mediators and their endogenous control receptors were used in the statistical analysis. Magnetic resonance imaging was performed in closed- and open-mouth positions and evaluated regarding disc position and presence of condylar and temporal erosions of the TMJ. Results. A high TNF level in relation to TNFsRII in TMJ synovial fluid correlated to the degree of TMJ condylar erosion. A high IL-1ra level in relation to TNF in TMJ synovial fluid was also correlated to the degree of TMJ condylar erosion. The total degree of TMJ condylar erosion was correlated with the number of painful regions. Conclusion. This study indicates that TNF in TMJ synovial fluid mediates TMJ cartilage and bone tissue resorption in RA. The study also suggests that the degree of endogenous cytokine control is of importance for development of bone tissue destruction.

Key Words:

• TMJ
• erosion
• MRI
• disc displacement
• cytokines
• rheumatoid arthritis

Acknowledgments

We thank Dr Laila Al-Harbi of the Department of Medicine for performing the medical examinations and Dr Sondos Abu Zenada of the Department of Oral Surgery, King Abdulaziz University for her skillful clinical work. This study was supported by unrestricted funding from Swedish Consultation to Per Alstergren at Karolinska Institutet. Dr Neveen Ahmed is the recipient of a PhD scholarship from the Ministry of Health, Jeddah, Saudi Arabia.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.