Tissue Engineering - The Elastic Tendon

Development of a novel tissue bioreactor for culturing tendons

Acute and chronic tendinopathies remain clinically challenging and novel and more efficacious treatment modalities are urgently needed. Tendons resemble connective tissue rich in highly organised collagen fibers, displaying a remarkably high tensile strength. However, partly due to the low number of cells present in the dense collagenous tissue and their avascular nature (i.e. low blood supply) tendons heal very slowly. Usually, a connective scar tissue forms at the injury site and the replaced tissue does not function adequately at high strain levels, increasing the chance that the tendon could get torn again later (re-rupture).

For a rational design of novel treatment modalities we need to pin down the molecular and cellular mechanisms underlying the slow regenerative capacity of tendons. In order to study tendon tissue under near-physiological conditions, a novel bioreactor was developed together with the “Höhere Technische Bundeslehr- und Versuchanstalt” (HTBLuVA) Salzburg, allowing the online monitoring of the biomechanical properties of organotypically cultured rat flexor tendons in vitro. The bioreactor will allow the culturing of tendon tissue under permanent or cyclic strain and the concomitant biomechanical characterisation of the tendons under various controlled treatment regimens. The design and execution of the bioreactor were carried out by the students of the graduating class at the HTBLuVA Salzburg. The bioreactor was designed in a modular fashion, each module being the focus of different student teams. In the second phase of the project the students used the newly designed bioreactor to study tendon biology, giving them the opportunity to plan and execute a scientific experiment. Further, this phase will also allow any necessary modifications of the bioreactor.

Taken together, the in vitro organotypic culture of tendons using the newly designed bioreactor provides a controllable environment enabling the systematic study of specific biological, biochemical, and biomechanical properties of tendons. One investigation has focused on the changes in tendon function after treatment with platelet-rich plasma (PRP). PRP is often used in the clinic to augment tendon healing, however the underlying mechanisms are poorly understood and the value of treatment with PRP is heavily debated.

This project has been completed.