Influence of Reproductive Status on Equine Serum Proteome: Preliminary Results.
Authors: Pennington Parker M, Splan Rebecca K, Jacobs Robert D, Wang Yan, Wagner Ashely L, Freeman Elizabeth W, Pukazhenthi Budhan S
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Serum Proteome Changes Across the Equine Reproductive Cycle Understanding how mares' physiology shifts between estrus, diestrus, early pregnancy and failed conception requires investigation beyond the uterus itself, yet circulating protein patterns during these critical reproductive windows have remained largely uncharacterised. Parker and colleagues used advanced mass spectrometry (Nano LC-MS/MS) to profile 308 distinct proteins in serum collected from three mares at key timepoints: day −1 to 0 (ovulation), day 12.5 post-ovulation in various states (cycling, pregnant, or unsuccessfully mated), identifying between 71 and 81 proteins that changed significantly (>1.5-fold difference) between reproductive states. Notably, several pregnancy-associated proteins previously detected only in intrauterine histotroph—including Apolipoprotein A-I, Complement C3, and Histone H4—were successfully identified circulating in peripheral serum, suggesting these could serve as accessible biomarkers for early pregnancy detection and reproductive monitoring. For practitioners, the ability to detect pregnancy-associated proteins in blood samples rather than relying solely on uterine secretion analysis offers a practical avenue for non-invasive assessment of reproductive status and early pregnancy viability, though larger, prospectively designed studies will be needed to validate these preliminary findings for clinical or breeding-management applications.
Read the full abstract on PubMed
Practical Takeaways
- •Serum protein profiling may enable development of non-invasive blood tests for early pregnancy detection and monitoring in mares, offering a practical alternative to current diagnostic methods
- •The presence of pregnancy-specific proteins in peripheral blood opens possibilities for improving reproductive management and troubleshooting subfertility in equine breeding programs
- •Further research with larger sample sizes is needed before clinical application, but this proteomics approach could eventually enhance breeding efficiency and reproductive outcomes in domestic horses
Key Findings
- •308 serum proteins were identified across different reproductive states in mares
- •71 differentially-expressed proteins (DEP) were found between estrus and diestrus, 72 between pregnant and diestrus, and 81 between non-pregnant and pregnant states
- •Pregnancy-specific proteins previously identified in equine uterine secretions (Apolipoprotein A-I, Complement C3, and Histone H4) were detectable in peripheral serum
- •Serum proteome analysis provides a non-invasive alternative to uterine secretion sampling for investigating early equine pregnancy biomarkers