Peer-review started: December 8, 2013
First decision: March 12, 2014
Revised: March 24, 2014
Accepted: July 17, 2014
Article in press: July 17, 2014
Published online: January 18, 2015
Osteoarthritis (OA) is a debilitating degenerative joint disease particularly affecting weightbearing joints within the body, principally the hips and knees. Current radiographic techniques are insufficient to show biochemical changes within joint tissue which can occur many years before symptoms become apparent. The need for better diagnostic and prognostic tools is heightened with the prevalence of OA set to increase in aging and obese populations. As inflammation is increasingly being considered an important part of OAs pathophysiology, cytokines are being assessed as possible candidates for biochemical markers. Cytokines, both pro- and anti-inflammatory, as well as angiogenic and chemotactic, have in recent years been studied for relevant characteristics. Biochemical markers show promise in determination of the severity of disease in addition to monitoring of the efficacy and safety of disease-modifying OA drugs, with the potential to act as diagnostic and prognostic tools. Currently, the diagnostic power of interleukin (IL)-6 and the relationship to disease burden of IL-1β, IL-15, tumor necrosis factor-α, and vascular endothelial growth factor make these the best candidates for assessment. Grouping appropriate cytokine markers together and assessing them collectively alongside other bone and cartilage degradation products will yield a more statistically powerful tool in research and clinical applications, and additionally aid in distinguishing between OA and a number of other diseases in which cytokines are known to have an involvement. Further large scale studies are needed to assess the validity and efficacy of current biomarkers, and to discover other potential biomarker candidates.
Core tip: This review discusses the role and significance of cytokines implicated in the pathophysiology and development of knee osteoarthritis. We aim to describe and summarize the current knowledge and advancement of the use of cytokines as biochemical markers in diagnosis and management of knee osteoarthritis (OA). Cytokines play an important role in the pathogenesis of OA. A better understanding of the biological mechanisms involved in this process may result in better treatment for OA patients. Biomarker investigation for OA diagnosis is still in the forefront of the research repertoire in OA. This review highlights some biomarker studies published in the PubMed database.