Research from the Royal Veterinary College (RVC) has shown that the blood supply to a horse’s tendon changes with age meaning older horses are at an increased risk of tendon injuries.
The study identified that as horses age they lose blood vessels in their tendons. This reduction in blood flow is the reason why tendon injuries heal more slowly and less effectively in older horses.
The RVC research team, which was led by Dr Nodoka Iwasaki, postdoctoral researcher, and Dr Chavaunne Thorpe, lecturer in basic sciences at the RVC’s Department of Comparative Biomedical Sciences, used advanced 3D technologies to capture detailed images of tendon tissue in the superficial digital flexor tendon from horse aged 2-5 years and 18-22 years.
The results revealed that older horses showed a 70% reduction in overall vascular volume, meaning far less blood was present within the tendon’s blood vessels.
It also found a 30% decrease in vessel diameter and a 74% reduction in the number of blood vessels overall, compared to younger horses.
This means that older tendons receive far less blood flow, making them more vulnerable to damage and slower to heal.
‘Crucial’ loss
“This study used advanced 3D imaging to reveal, for the first time, how the blood supply to the horse’s tendon changes with age,” said Dr Iwasaki.
“We found that older tendons lose many of their larger blood vessels, which are crucial for repair and recovery.
“This helps explain why older horses are more prone to tendon injuries and why these injuries heal more slowly.
“We are now exploring ways to prevent this age-related decline, with the aim of improving outcomes for older horses diagnosed with tendon injury.”
Vascular changes
The research team also observed an increase in the formation of smaller blood vessels within aged tendons, suggesting that the tissue attempts to compensate for the loss of larger vessels.
However, this new vascular network appeared disorganised, indicating a loss of vascular balance, meaning the normal structure and coordination of blood vessels is disrupted.
These changes suggest that the new disorganised vessels may not function effectively, reinforcing the need to monitor tendon health closely as horses age.
The research was funded by the Horserace Betting Levy Board in collaboration with the Aristotle University of Thessaloniki in Greece.
