Role of Interleukin-6 on Osteoclasts, Osteoblasts and Osteocytes in Rheumatoid Arthritis

Abstract

Rheumatoid arthritis（RA）is a common form of inflammatory arthritis leading to progressive bone and joint destruction. Because RA patients with progressive bone destruction experience an accelerated decrease in their quality of life, inhibition of disease progression and bone destruction has become an important clinical goal. Bone-related cells and inflammatory cytokines such as TNF-α and Interleukin-6（IL-6）are closely involved in bone destruction, and bone destruction is suppressed by drug intervention targeting these proinflammatory cytokines. In particular, recent studies have reported that the intervention of tocilizumab, an anti-IL-6 receptor antibody, results in bone repair in addition to suppression of bone and joint destruction, and these results suggest the potential for new therapeutic goals. Regarding the relationship between IL-6 and bone, many studies on osteoclasts have been published over many years; however, more recent studies have explored the relationship of IL-6 with osteoblasts and osteocytes. This review summarizes the relationship between IL-6 and bone-related cells from the perspective of clinical research and basic research such as in vitro and in vivo studies, and the possibility of IL-6 signal blockade in RA treatment.