The role of cytokines and growth factors in rheumatoid joint destruction

: Cytokines and growth factors are important mediators of inflammation and play a major role in both the physiological regulation of bone and cartilage metabolism, and in the destruction of joint-related structures. These complex biological regulatory events have to be regarded as net effects which are dependent on the individual actions of the different cytokines and their corresponding inhibitors in the pericellular environment of the cells present in the inflamed tissues. These effects can be antagonized on various levels by natural or artificial inhibitory molecules. The determination and characterization of cytokines and their inhibitors in body fluids and tissues may contribute to a better understanding of the basic mechanisms of the pathogenesis of inflammatory joint diseases, and may help to develop better modalities of therapy. The objective of the present review is to outline important actions of selected cytokines and growth factors on cells and the surrounding matrix of bone and cartilage in rheumatoid arthritis. It will focus on interleukin-1 (IL-1), IL-1 inhibitors, Tumor-Necrosis-Factor-alpha (TNF-alpha), TNF inhibitors, Interleukin-6 (IL-6), colony-stimulating factors (CSF's), Interferon-gamma (IFN-gamma), growth factors, eicosanoids and prostaglandins, all of which are important in the effector phase of tissue destruction.