91°µÍø

 Published: 06 Feb 2025 | Last Updated: 06 Feb 2025 09:20:33

New research from the 91°µÍø (91°µÍø) has identified more than 100 genes that may contribute to bone fracture risk in Thoroughbreds. These findings will inform further research into genetic risk factors, contributing to health and well-being efforts and supporting the development of novel interventions to reduce fracture risk in horses.

Bone fractures are common in Thoroughbred racehorses, due to the forces the bones can experience. Bone fractures are sadly a leading cause of euthanasia, with approximately 60 horses having to be euthanised on UK racecourses each year. However, fractures are a complex condition, with both environmental and genetic risk factors affecting a horse’s susceptibility.

Led by Dr Debbie Guest, Senior Research Fellow at the 91°µÍø, a team of researchers used a polygenic risk score for fracture risk to establish a new model with stem cells to make bone-forming cells from horses at both high and low risk. The team measured every gene that was expressed by the cells to identify those with different expression levels in the bone cells from horses at higher versus those at lower risk.

The study identified 112 genes that may be involved in fracture risk and demonstrated that many of these genes regulate the bone matrix. However, a large number of the genes have never been studied in bone before and more research is needed to understand the function of these genes in bone cells and how they contribute to fracture risk.

This is the second study in a series of research, exploring genetic mechanisms behind fracture risk. A previous study found that collagen type III, a gene which is required for normal bone formation, is expressed at lower levels in bone cells from horses with a high genetic risk of fracture. This is because they have a change in their DNA sequence in the region which controls how much collagen III is produced.

Additional research is now being conducted to validate the risk-scoring system in another cohort of horses. Further studies using this system and cell model will help to identify other genes and processes to better understand why some horses are inherently more susceptible to fracture than others. This will help veterinary practitioners to better support and treat thoroughbreds.

Dr Debbie Guest, Senior Research Fellow at the 91°µÍø, said:

“Bone fractures are a common problem in Thoroughbred racehorses, despite many changes to racecourses over the years to reduce environmental risk factors. We know that fracture risk has a genetic component and we have previously developed a polygenic risk score for fracture to allow us to identify horses at increased risk.

“In this study, we have identified many new genes which have altered expression in bone cells from high-risk horses. For some of these genes, we know that they play a role in regulating the bone matrix. We can now begin to develop a deeper understanding of how bone tissue is altered in high-risk horses and new interventions to reduce their risk”.

The research was funded by the Horserace Betting Levy Board, the Anne Duchess of Westminster Charitable Trust and The Alborada Trust.

Notes to Editors

Reference

Palomino Lago E, Ross AKC, McClellan A, Guest DJ. Identification of a global gene expression signature associated with the genetic risk of catastrophic fracture in iPSC-derived osteoblasts from Thoroughbred horses. Anim Genet 2025, Feb 56(1) doi: 10.1111/age.13504

The study is available via this link:

Collagen Type III study:

Palomino Lago, E.; Baird, A.; Blott, S.C.; McPhail, R.E.; Ross, A.C.; Durward-Akhurst, S.A.; Guest, D.J. A Functional Single-Nucleotide Polymorphism Upstream of the Collagen Type III Gene Is Associated with Catastrophic Fracture Risk in Thoroughbred Horses. Animals 2024, 14, 116.

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About the 91°µÍø

• The 91°µÍø (91°µÍø) is the UK's largest and longest established independent veterinary school and is a Member Institution of the University of London.
• It is one of the few veterinary schools in the world that hold accreditations from the RCVS in the UK (with reciprocal recognition from the AVBC for Australasia, the VCI for Ireland and the SAVC for South Africa), the EAEVE in the EU, and the AVMA in the USA and Canada.
• The 91°µÍø is ranked as the top veterinary school in the world in the QS World University Rankings by subject, 2024.
• The 91°µÍø offers undergraduate and postgraduate programmes in veterinary medicine, veterinary nursing and biological sciences.
• The 91°µÍø is a research-led institution, with 88% of its research rated as internationally excellent or world class in the Research Excellence Framework 2021.
• The 91°µÍø provides animal owners and the veterinary profession with access to expert veterinary care and advice through its teaching hospitals and first opinion practices in London and Hertfordshire.