Differences in serum biomarkers between combined glucosamine and chondroitin versus celecoxib in a randomized, double-blind trial in osteoarthritis patients

BACKGROUND: Non-steroidal anti-inflammatory drugs, e.g., celecoxib, are commonly used for inflammatory conditions, but can be associated with adverse effects. Combined glucosamine hydrochloride plus chondroitin sulfate (GH+CS) are commonly used for joint pain and have no known adverse effects. Evidence from in vitro, animal and human studies suggests that GH+CS have anti-inflammatory activity, among other mechanisms of action. OBJECTIVE: We evaluated the effects of GH+CS versus celecoxib on a panel of 20 serum proteins involved in inflammation and other metabolic pathways. METHODS: Samples were from a randomized, parallel, double-blind trial of pharmaceutical grade 1500 mg GH + 1200 mg CS (n=96) versus 200 mg celecoxib daily (n=93) for 6-months in knee osteoarthritis (OA) patients. Linear mixed models adjusted for age, sex, body mass index, baseline serum protein values, and rescue medicine use assessed the intervention effects of each treatment arm adjusting for multiple testing. RESULTS: All serum proteins except WNT16 were lower after treatment with GH+CS, while about half increased after celecoxib. Serum IL-6 was significantly reduced (by 9%, P=0.001) after GH+CS, and satisfied the FDR<0.05 threshold. CCL20, CSF3, and WNT16 increased after celecoxib (by 7%, 9% and 9%, respectively, P<0.05), but these serum proteins were no longer statistically significant after controlling for multiple testing. CONCLUSION: The results of this study using samples from a previously conducted trial in OA patients, demonstrate that GH+CS reduces circulating IL-6, an inflammatory cytokine, but is otherwise comparable to celecoxib with regard to effects on other circulating protein biomarkers.