Alpha-2 adrenergic stimulation triggers Achilles tenocyte hypercellularity: comparison between two model systems
2013 (English)In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 23, no 6, 687-696 p.Article in journal (Refereed) Published
The histopathology of tendons with painful tendinopathy is often tendinosis, a fibrosis-like condition of unclear pathogenesis characterized by tissue changes including hypercellularity. The primary tendon cells (tenocytes) have been shown to express adrenoreceptors (mainly alpha-2A) as well as markers of catecholamine production, particularly in tendinosis. It is known that adrenergic stimulation can induce proliferation in other cells. The present study investigated the effects of an exogenously administered alpha-2 adrenergic agonist in an established in vivo Achilles tendinosis model (rabbit) and also in an in vitro human tendon cell culture model. The catecholamine producing enzyme tyrosine hydroxylase and the alpha-2A-adrenoreceptor (α(2A) AR) were expressed by tenocytes, and alpha-2 adrenergic stimulation had a proliferative effect on these cells, in both models. The proliferation was inhibited by administration of an α(2A) AR antagonist, and the in vitro model further showed that the proliferative alpha-2A effect was mediated via a mitogenic cell signaling pathway involving phosphorylation of extracellular-signal-regulated kinases 1 and 2. The results indicate that catecholamines produced by tenocytes in tendinosis might contribute to the proliferative nature of the pathology through stimulation of the α(2A) AR, pointing to a novel target for future therapies. The study furthermore shows that animal models are not necessarily required for all aspects of this research.
Place, publisher, year, edition, pages
John Wiley & Sons, 2013. Vol. 23, no 6, 687-696 p.
tendinopathy, exercise, cytokines, neurotrophins, alpha(2A) adrenoreceptor, Tendinosis, Achilles tendon
Sport and Fitness Sciences Microbiology in the medical area
IdentifiersURN: urn:nbn:se:umu:diva-53462DOI: 10.1111/j.1600-0838.2011.01442.xPubMedID: 22292987OAI: oai:DiVA.org:umu-53462DiVA: diva2:512364
FunderSwedish Research Council, 521-2009-2921Swedish National Centre for Research in Sports, 54/10, P2011-0170