Grant: Operating Grant - PA: Musculoskeletal Health, Arthritis, Skin and Oral Health

Repetitive-use tendon injury (traditionally called 'tendinitis' is a major clinical burden in many Canadian industries. There is only limited understanding of how this condition develops; the term for development of a medical condition is called 'pathogenesis'. If we understand the factors that initiate tendon damage in repetive-use jobs like at checkout counters or in the lumber or fishing industries, we will be in a much better position to develop effective treatments. When studying painful, damaged tendon from patients undergoing surgery for long-term tendon pain, we (and others) have found that the blood vessels in the damaged area are very abnormal. There are an excessively large number of small vessels - 'microvessels'. We have shown that these vessels are increasing in number (proliferating) and producing a factor that stimulate futher vessel development. This is called vascular endothelial growth factor (VEGF). A commonly-used clinical diagnostic test - ultrasound scanning - has shown that increased tendon vascularity is associated with tendon pain. (But the relationship is not perfect.) Thus, there is a good reason to investigate whether tendon vessels proliferate during periods of repetitive-use as a result of local VEGF production. This vascular proliferation may have harmful effects on tendon structure and function. If this proves to be the case, it will provide an important new target for treatment. There are already drugs that are used to treat abnormal vessel proliferation in other conditions, so if our hypothesis is proven, progress from research to treatment may be relatively fast.