We've just published an article in the Scandinavian Journal of Medicine and Science in Sports investigating the inflammatory response of tendons to overload injury. We have shown that the interfascicular matrix is constantly turning over faster than the rest of the tendon matrix. However, in response to overload, the whole tendon shows inflammation and a degenerative response.

C. T. Thorpe, S. Chaudhry, I. I. Lei, A. Varone, G. P. Riley, H. L. Birch, P. D. Clegg and H. R. C. Screen (2015) Tendon overload results in alterations in cell shape and increased markers of inflammation and matrix degradation. Article first published online: 30 DEC 2014 | DOI: 10.1111/sms.12333

Tendon inflammation in response to overuse

Tendon injuries are common both in athletes and the general population. Unfortunately, the ability of tendon to repair is very poor, so injuries will often persist for many years. We have a limited understanding of how tendon injuries develop, which has restricted our ability to produce effective treatments.

Scientists have always thought that tendons are damaged as a result of overuse, and that the cells in tendons are unable to repair the damage. Many previous studies have not shown any evidence of inflammation in damaged tendon tissue. However, these studies were often carried out on tendons several months after the injury occurred, and so do not help us to understand the early stages of injury development.

In this study, we specifically looked at the immediate response to tendon injury, in order to try and understand the process more fully. We took pieces of tendon and subjected to them to high loads, simulating the conditions leading to injury. We then looked at the tendon response to damage straight away.

We found that damaged tendon had higher levels of various markers of inflammation, as well as increased levels of tissue breakdown, all indicating an early inflammatory response from the tendon cells. This inflammation soon after an injury may actually be beneficial to the healing of tendons. The potential to change this response provides exciting avenues for future research, and may help us prevent long term tendon damage altogether.