Expression and functional role of adenosine receptors in regulating inflammatory responses in human synoviocytes

Chronic inflammation is a significant factor in the pathophysiology of many forms of joint diseases. The discovery of the detailed processes of inflammation has revealed a close relationship between inflammatory diseases and the presence of purine receptors. Adenosine has been reported to reduce inflammation in several in vivo models suggesting a potential value of this purine nucleoside as a therapeutic mediator of joint inflammation able to limit articular cartilage degeneration and joint destruction. Growing evidence also suggests that extracellular nucleotides, acting through purinergic receptors, play a central role in the regulation of bone and cartilage metabolism. Fibroblast-like synoviocytes are closely involved in the pathogenesis of joint destruction by an increased proliferation and by the secretion of a wide range of pro-inflammatory mediators including cytokines, growth factors and lipid mediators.