Chapter 14 - Osteoarthritis and the Immune System

Abstract

Osteoarthritis (OA) is the most common joint disorder and is a leading cause of disability in the adult population. It is now appreciated that all components of the joint, including the cartilage, calcified cartilage, synovial joint lining, and periarticular bone undergo pathological changes during the initiation and progression of OA. Some of these alterations can be attributed to direct injury and mechanical disruption of the tissues, but in general, the mechanisms are dependent on active cell-mediated processes. The field of osteoimmunology has helped to demonstrate that many of the mediators that are involved in the regulation of immune cell function also play important roles, in both physiological, as well as pathological bone remodeling. This review will focus on the mechanisms involved in periarticular bone changes in OA, with special attention on the role of mediators and immunomodulators that regulate physiological and pathological bone remodeling. A deeper understanding of the specific and unique roles of these mediators, and their downstream targets will provide mechanistic insights into the pathologic processes that affect the bone and other joint tissues in OA, but also may identify potential therapeutic targets for treatment of this debilitating disease.