The anti-tumor necrosis factor (TNF)-α treatment infliximab significantly improves bone metabolism in patients with rheumatoid arthritis (RA), report researchers.
Osteoporosis associated with RA is controlled by pro-inflammatory cytokines such as TNF-α, suggesting that anti-TNF-α treatments such as infliximab benefit bone health, note Thierry Thomas (University Hospital of St-Etienne, Paris, France) and co-workers.
They looked specifically at the effect of infliximab on collagen degradation as indicated by levels of the type 1 collagen telopeptide fragments CTX-I and ICTP; bone formation indicated by concentrations of pro-collagen serum type I collagen (PINP); and cartilage breakdown as shown by levels of urinary CTX-I.
Among the 48 women with severe RA who were studied, serum CTX-I levels were found to decrease by 19% and 28% after 6 and 22 weeks of infliximab therapy, respectively.
Conversely, 54 weeks of treatment was associated with a significant 25% decline in ICTP concentrations. PINP levels were generally stable, suggesting a 30-40% improvement in the bone re-modeling balance when the decreases in CTX and ICTP were taken into account. Urinary levels of CTX-II, reflecting cartilage breakdown did not change significantly changed at any point.
"In summary, our study suggests beneficial effects of infliximab therapy on bone metabolism in patients with severe RA," the researchers write in the Annals of the Rheumatic Diseases.
"Further studies are needed to evaluate whether these changes in bone turnover markers ratios and cartilage marker levels are predictive of structural effects of infliximab therapy," the investigators add.