Abstract
Background
Osteoarthritis (OA) has been described as a non-inflammatory arthritis and yet the choice of drug treatment is NSAIDs.
Aim
To test the hypothesis that cytokines and chemokines are associated with inflammation in OA.
Methods
Synovium biopsy and synovial fluid of 17 patients undergoing total knee arthroplasty (TKR) were sampled at the onset of their surgery. Histology of synovium and immunoassay of synovial fluid were conducted. A 3 point scale, 3 being the most cellular, was used to assess the cellularity of synovium histology slides, a parameter known to correlate with several markers of OA. Synovial fluid was analysed using a multi-anylate fluorescent immunoassay. In brief, cytokines and chemokines associated with inflammation were quantified, namely IL-12, TNF, IL-10, IL-6, IL-1, IL-8.
Results
The 3 point scale used to describe the cellularity of the synovium placed the majority in groups 2 and 3. Low levels (<120 pg/ml) of IL-12, IL-10, IL-1 and TNF were measured in all 3 cellularity groups. Markedly elevated values of IL-6 and IL-8 were measured in the synovial fluid of knees with the most cellular synovium (maximum values were 8325 pg/ml and 1540 pg/ml respectively).
Conclusion
Elevated levels of IL-6 are associated with bone resorption, being clinically linked with aseptic loosening. IL-8 is capable of promoting angiogenesis and can act as a chemokine which attracts T cells. T cells were identified in the synovium of OA patients indicating an inflammatory component to the heterogeneous disease of OA.
