Advances in the development and influence factors of osteophytes in osteoarthritis

Abstract

Osteoarthritis (OA) is a common chronic arthritis, mainly suffering the middle and elderly patients, and it is the main cause of arthralgia and articular functional disturbance. Studies have suggested that osteophyte formation was closely connected with the development of OA due to the stabilization of suffered joints and arthralgia induced by osteophytes. In tissue constitution and pathology, osteophyte is made up of bone, cartilage and connective tissue, stemming from MSCs. With the development of osteophytes, the proportion of bone increases while the proportion of cartilage and connective tissue decreases. What's more, in promotion factors of osteophytes, osteophyte formation was induced by the biomechanical and biochemical factors and their both effect. The biomechanical factors result from imbalance of articular biomechanics induced by cartilaginous degeneration and ligament trauma. And the biochemical factors result from alteration of articular microenvironment induced by metabolic disorder of chondrocytes and synovitis. Furthermore, the both effects that the biomechanical factors induces biochemical alterations also co-promote osteophyte formation. And studies on the mechanism indicated that osteophyte formation was regulated by several signaling pathways and cytokines. TGF-β superfamily and Hedgehog signaling pathway were involved in modulating osteophyte formation. TGF-β and BMPs modulated the initiation and late stage of osteophyte formation respectively. And Hedgehog signaling pathway regulated the osteophyte formation with modulating the hypertrophy of chondral osteophytes. This paper emphatically reviews the development and mechanism of osteophytes in OA for deeply understanding the OA and bringing new ideas and methods for the precaution and treatment of OA.