Effects of etamsylate on equine platelets: in vitro and in vivo studies.
Authors: Segura Dídac, Monreal Luis, Pérez-Pujol Sílvia, Alonso Antonio, Díaz-Ricart Maribel, Brugués Rosa, Ordinas Antonio, Escolar Ginés
Journal: Veterinary journal (London, England : 1997)
Summary
Etamsylate, a haemostatic agent used clinically in equine practice, was investigated for its effects on platelet function through complementary laboratory and live animal experiments. Seven horses were used for in vitro studies where blood samples were exposed to various etamsylate concentrations, with platelet activation assessed via P-selectin expression and annexin V binding using flow cytometry; a further eight horses received intravenous etamsylate and blood samples were analysed at baseline, 1 hour and 2 hours post-administration. The in vitro findings demonstrated clear platelet pre-activation, with significant increases in P-selectin expression, leukocyte-platelet aggregate formation and phosphatidylserine exposure (annexin V binding), suggesting direct cellular effects of the drug. In vivo results were more variable—whilst marked P-selectin elevation occurred in two horses and heterotypic aggregates in five horses, these changes were not statistically significant across the whole cohort, indicating substantial individual variation in response. These findings warrant careful clinical consideration: whilst etamsylate may reliably activate platelets in standardised laboratory conditions, its inconsistent in vivo effects highlight the complexity of translating in vitro haemostatic activity to predictable clinical outcomes in individual horses, necessitating further investigation into factors determining patient-to-patient variability.
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Practical Takeaways
- •Etamsylate may activate equine platelets in vitro, suggesting caution when considering this hemostatic agent in clinical practice given variable individual responses
- •In vivo platelet activation from etamsylate administration was inconsistent between horses, indicating individual variation in response that warrants clinical monitoring if used
- •Further investigation needed before routine clinical use; current evidence suggests potential for unwanted platelet pre-activation effects in some horses
Key Findings
- •In vitro etamsylate exposure significantly increased P-selectin expression, leukocyte-platelet aggregate formation, and annexin V binding in equine platelets
- •In vivo IV etamsylate administration produced marked P-selectin expression increases in 2/8 horses and heterotypic aggregate formation in 5/8 horses
- •Results suggest etamsylate induces a pre-activation state in equine platelets in vitro, though in vivo effects were inconsistent across animals