Inflammatory mechanisms in tendinopathy - towards translation

Tendinopathy is a multifactorial spectrum of tendon disorders that affects different anatomical sites and is characterized by activity-related tendon pain. These disorders are common, account for a high proportion (similar to 30%) of referrals to musculoskeletal practitioners and confer a large socioeconomic burden of disease. Our incomplete understanding of the mechanisms underpinning tendon pathophysiology continues to hamper the development of targeted therapies, which have been successful in other areas of musculoskeletal medicine. Debate remains among clinicians about the role of an inflammatory process in tendinopathy owing to a lack of clinical correlation. The advent of modern molecular techniques has highlighted the presence of immune cells and inflammatory mechanisms throughout the spectrum of tendinopathy in both animal and human models of disease. Key inflammatory mediators-such as cytokines, nitric oxide, prostaglandins and lipoxins-play crucial parts in modulating changes in the extracellular matrix within tendinopathy. Understanding the links between inflammatory mechanisms, tendon homeostasis and resolution of tendon damage will be crucial in developing novel therapeutics for human tendon disease.