Alterations of Circulating Biomarkers During Late Term Pregnancy Complications in the Horse Part I: Cytokines.
Authors: Fedorka C E, Ball B A, Walker O F, McCormick M E, Scoggin K E, Kennedy L A, Squires E L, Troedsson M H T
Journal: Journal of equine veterinary science
Summary
# Editorial Summary Late-term pregnancy loss in mares results from diverse aetiologies, yet most clinical understanding derives from experimental ascending placentitis models. Fedorka and colleagues tracked 702 Thoroughbred mares throughout pregnancy with weekly blood sampling, submitting fetal membranes from 38 cases (six ascending placentitis, six focal mucoid placentitis, six idiopathic abortion, and 20 controls) for pathological classification whilst simultaneously measuring six key inflammatory cytokines (IL-2, IL-5, IL-6, IL-10, IFN-γ, and TNF) via immunoassay. Both infectious placentitis variants—ascending and focal mucoid—demonstrated significantly elevated concentrations of all six cytokines in the weeks preceding parturition compared to healthy controls (P < 0.05), whereas mares experiencing idiopathic abortion showed no detectable cytokine elevation. These findings suggest that systemic inflammatory biomarkers may serve as predictive tools for identifying infectious placental compromise in real-world conditions, though their absence doesn't exclude all pregnancy complications, indicating that non-infectious fetal losses present distinct immunological profiles warranting separate diagnostic approaches.
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Practical Takeaways
- •Serial measurement of circulating cytokines (IL-2, IL-5, IL-6, IL-10, IFN-γ, TNF) during late pregnancy could help identify mares at risk for infectious placental disease before abortion occurs, enabling early intervention.
- •Idiopathic abortions do not show cytokine elevation, so normal cytokine profiles do not rule out all causes of fetal loss; additional diagnostic investigation remains necessary.
- •Focal mucoid placentitis now recognized as an infectious condition with characteristic cytokine elevation—practitioners should be aware this entity carries similar inflammatory burden to ascending placentitis.
Key Findings
- •Serum concentrations of IL-2, IL-5, IL-6, IL-10, IFN-γ, and TNF increased significantly (P < 0.05) preceding parturition in mares with ascending placentitis and focal mucoid placentitis compared to controls.
- •Cytokine profiles preceding idiopathic abortion did not differ from control mares, indicating inflammatory cytokines are specific to infectious placental causes.
- •This is the first study documenting increased cytokine profiles during focal mucoid placentitis (Nocardioform placentitis), expanding the known biomarker signature beyond ascending placentitis.
- •Serum cytokines may serve as potential predictive biomarkers for placental infection in late-gestation mares.