Tendon regeneration versus Tendon repair

Tendon Injuries – Scaring Repair and Scarless Regeneration

Together with student of the HBLVA Rosensteingasse we want to look into a fundamental problem of current sports medicine: The treatment and healing of tendon injuries. Tendon injuries are amongst the most frequently occurring musculoskeletal injuries in equine as well as human patients and especially in athletes of both species. Current therapies, however, do not lead to tendon regeneration but only to inferior scarring repair causing significantly reduced tendon elasticity and high re-injury rates. This fact poses a fundamental problem in human as well as veterinary sports medicine. In both, horses and humans, a considerable number of athletes are forced to end their career early due to tendon injuries. Especially racing thoroughbreds but also a considerable number of event, dressage and show jumping horses suffer from tendinopathies. The equine superficial digital flexor tendon (SDFT) is the structure most at risk for suffering an injury. The incidence of SDFT tendinitis in horses is reported to be as high as 8-43% . Injured tendons do not regenerate but form scar tissue with significantly inferior biomechanical properties. Therefore, in horses even after apparent initial recovery, reinjury rates of up to 80% are reported.

In human professional as well as recreational athletes 30-50% of all sports related injuries affect tendons. The Achilles tendon especially in elite runners is prone to injury with a lifetime risk of up to 52% and an annual incidence rate of 7-10,9%. The incidence of Achilles tendon injuries has increased during recent decades probably owing to more strenuous hobbies and increased strain in competitive sports. This is even more concerning as an association seems to exist between Achilles tendinopathies and diseases of our times such as obesity, diabetes mellitus and hypertension, or the supplemental use of estrogen and local or systemic steroids.

In recent years the attention of regenerative medical research was drawn towards tendon treatments. It was shown that fetal tissues have the inherent capacity to regenerate without scar formation. The regenerative potential of fetal tissue which is considered to be an inherent property of immature tissue offers a model to understand scarless healing of tendon tissue. Hence, a potential solution for improving adult tendon healing would be defining and utilising the mechanisms involved in fetal healing. It will advance our understanding of the ideal environment for tendon regeneration and open new avenues for future approaches to tendon therapies.

Together with the students we will contribute to map these distinct differences. Supervised by scientific experts the students will compare processes of adult and fetal tendon healing. Aim is to identify key factors in fetal tendon healing processes that are distinct from the adult counterparts. We also hope to increase our understanding if and how the identified factors may be applicable for future therapeutic use. The sheep will serve as model for the horse and the human.

The study will be carried out in the laboratories of the project partners, embedding the students into an interdisciplinary team of scientists. Accompanied by specialists in each respective field of the project the students will have the opportunity to approach the scientific questions of interest using the most advanced techniques of secretome-, gene expression-, cell biological and histological analysis. It is our aim that the students not only gain knowledge but also obtain scientific results through their own work. They will get the chance to use hands on techniques they learned at school and above that will get to know a variety of new techniques. The envisaged project not only aims at testing new regenerative hypotheses but will also pave the way to raise new exciting research questions.