Background/Purpose: Synovitis is one of the major signs of structure damage in osteoarthritis (OA) progression. Chondroitin sulfate (CS) is an effective drug in the treatment of OA since it can reduce joint swelling and effusion in OA patients as described in the NIH-funded GAIT study. Therefore, the aim of this study was to compare the effect of CS vs. acetaminophen on synovitis in OA patients and to evaluate their impact on chemokine concentrations.

Methods: Synovitis (synovial hypertrophy+effusion≥4mm) assessed by sonography and synovial effusion quantified by artrhocentesis were evaluated in 45 patients treated with CS (800mg/day) or acetaminophen (4g/day) for 6 months. Patients were followed-up until month 9 to evaluate the carry-over effect. Symptomatic effect of both treatments was also evaluated by Lequesne Algofunctional Index (baseline,1.5, 3, 6 and 9 months). The levels of CXCL16, fractalkine/CX₃CL1, MCP-1/CCL-2, RANTES/CCL5 and GRO-α/CXCL1 were determined by ELISA in the plasma and synovial samples collected in each visit. Analysis of continuous variables was based on analyses of covariance (ANCOVA) model. Study of the chemokine variations between each time and the baselines was performed by a Wilcoxon two-related samples test Comparison between the two groups was obtained using an independent sample t-test for quantitative variables or a chi-squared test for qualitative variables. P values ≤0.05 were considered statistically significant for each variable.

Results: Eligible patients had clinical and radiographic evidence of OA (K&L grade 2 and 3) with synovitis. Mean age of patients was 70.4 years being women 72.1% of them. Mean BMI was 28.97. At the end of the study, CS significantly reduced synovitis compared to acetaminophen (p<0.01).This significant reduction was also detected in MCP-1 and fracktalkine synovial levels. Compared to baseline, CS treated patients showed significant reductions in synovitis (25.5%) and significant impairment of synovial hypertrophy (61.9% reduction). These effects were accompanied by significant decreases in synovial and serum MCP-1 content. In contrast, in the acetaminophen-treated group no effect on synovitis was observed and increased synovial RANTES levels were even detected. Additionally, CS but not acetaminophen effectively reduced functional incapacity after 6 months of treatment (CS-treated group: 11.5±2.5 vs. 7.9±3.0; p<0.01; acetaminophen-treated group: 9.9±4.1 vs. 8.3±4.9; n.s.). CS functional improvement remained after 3 months treatment cessation (month 9) thus confirming CS carry-over effect.

Conclusion:

These results indicates that CS but not acetaminophen effectively reduces synovitis and clinical symptoms in OA patients. Evidence of an anti-inflammatory effect for CS has been also provided since it can decrease synovial and plasma levels of relevant chemokines. This study also adds further support and extends the finings described in the NIH-funded GAIT study and suggests that CS seems to be a more effective therapeutic tool for OA and synovial inflammation than analgesics.

This work was supported by grants SAF2011-23777, PI/08/1875, RIER RD08/0075/0016, RIER RD08/0075/0021 and other grants from Generalitat Valenciana.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/condroitin-sulfate-decreases-chemokine-levels-and-synovitis-in-knee-osteoarthritis-patients/