These findings from the Royal Veterinary College (RVC) will help develop a better understanding of why older horses (and humans) are more prone to tendon injuries and inform future treatments.
The cells in tendons are responsible for maintaining tendon structure by repairing any damage.
The main type of cells in tendons are called tenocytes, which are well-researched yet, little is known about other types of cells present and how they are affected by ageing.
Lead researcher, Dr Chavaunne Thorpe, lecturer in basic sciences at the RVC; her post-doctoral research associate Dr Danae Zamboulis; Professor Peter Clegg of the University of Liverpool; Professor Hazel Screen of the Queen Mary University of London and Professor Helen Birch (UCL), took part in the project.
They set out to identify the different cell populations in horses’ superficial digital flexor tendon, similar in function to the human Achilles tendon, and discover which are most affected by ageing.
They used a technique called single cell RNA sequencing to identify the different cell types in superficial digital flexor tendons from both young and old horses.
In total, the research team identified 11 different types of cells. This included several different populations of tenocytes as well as cells associated with blood vessels and the immune system.
Findings concluded that one tenocyte population and one blood vessel-associated population were particularly affected by ageing, with an altered ability to maintain tendon structure and respond to injury in these cell types.
Identifying and characterising the different cell populations and establishing their function in healthy tendons is the first step to understanding how altered cell function contributes to age-related tendon injury.
This work will allow the development of treatments for tendon injury targeted at those cells affected most by ageing.
Chavaunne said: “Our results uncover just how complex and variable cell populations in tendons are, and show that some cells are particularly prone to age-related alterations, helping to explain why the risk of tendon injury is higher in older individuals.
“The findings of these experiments will allow future studies to develop therapeutics for tendon injuries targeted at specific cell populations.”