Expression of select mRNA in Thoroughbreds with catastrophic racing injuries.
Authors: Page Allen E, Adam Emma, Arthur Rick, Barker Virginia, Franklin Forrest, Friedman Ron, Grande Timothy, Hardy Michael, Howard Bruce, Partridge Emma, Rutledge Matthew, Scollay Mary, Stewart John C, Vale Alina, Horohov David W
Journal: Equine veterinary journal
Summary
# Expression of select mRNA in Thoroughbreds with catastrophic racing injuries Catastrophic racing injuries represent a critical welfare and economic concern for the racing industry, yet identifying at-risk horses before injury occurs remains challenging. This prospective cohort study analysed mRNA expression patterns from 686 blood samples collected across five US racing jurisdictions, comparing 107 catastrophically injured horses with non-injured controls sampled both before and after racing. Of 21 genes initially examined, only three demonstrated significant discriminatory power between injured and uninjured horses: IGF-1 (insulin-like growth factor 1), IL1RN (interleukin-1 receptor antagonist) and MMP2 (matrix metalloproteinase 2). When combined into predictive models, these three genes achieved sensitivities of 76–82% and specificities of 84–88%, suggesting reasonable utility as biomarkers for identifying pre-race vulnerability. The practical significance lies in the potential development of a non-invasive blood test capable of flagging horses at elevated risk before they race, allowing for informed decisions regarding entry and training modifications. However, practitioners should note that twelve other genes initially showed post-race expression changes and required exclusion, highlighting the importance of sampling timing and the need to distinguish between injury-associated molecular signatures and normal post-exercise inflammatory responses. Whilst these findings represent an encouraging proof-of-concept, further validation across different cohorts and racing populations will be essential before implementation into routine pre-race screening protocols.
Read the full abstract on PubMed
Practical Takeaways
- •A simple blood test measuring three specific genes (IGF-1, IL1RN, MMP2) may help identify high-risk horses before racing, potentially preventing catastrophic injuries
- •This noninvasive screening tool could become an accessible and economical addition to pre-race veterinary evaluation protocols
- •The high sensitivity and specificity (76-88%) suggests clinical utility, but further validation studies are needed before widespread implementation in racing operations
Key Findings
- •Three genes (IGF-1, IL1RN, MMP2) showed significant differential expression between catastrophically injured and noninjured horses
- •mRNA expression models demonstrated 76-82% sensitivity and 84-88% specificity for identifying horses at risk of catastrophic injury
- •Twelve genes showed significant changes within 45 minutes postrace and were excluded from injury risk analysis
- •Blood-based mRNA analysis from 107 catastrophically injured horses and 579 noninjured horses across five US racing jurisdictions