Prothrombotic events in the prodromal stages of acute laminitis in horses.
Authors: Weiss, Trent, Johnston
Journal: American journal of veterinary research
Summary
# Editorial Summary: Prothrombotic Events in Acute Laminitis Weiss, Trent and Johnston (1996) investigated the haemostatic mechanisms underlying the early stages of carbohydrate-induced laminitis, hypothesising that thrombotic events within the hoof vasculature might drive the pathological cascade leading to lameness. Using five horses, the researchers administered carbohydrate overload and measured platelet kinetics, coagulation parameters, and vessel thrombosis via contrast arteriography and histological examination; four horses developed clinical lameness within 28–52 hours of dosing. The critical finding was a marked reduction in platelet survival by six hours post-induction—notably earlier than clinical signs—whilst systemic coagulation markers (prothrombin time, activated partial thromboplastin time, monocyte procoagulant activity) showed minimal or no statistically significant change. Contrast imaging revealed substantially compromised blood supply to affected hooves, and microthrombi were identified within the laminar dermal venules of two affected horses, suggesting local rather than systemic thrombotic activation. These findings underscore that early platelet consumption and regional vascular dysfunction, rather than widespread coagulation activation, characterise the prodromal phase of laminitis—a distinction with implications for understanding both disease mechanisms and potential therapeutic windows before irreversible laminar damage occurs.
Read the full abstract on PubMed
Practical Takeaways
- •Thrombotic events occur very early in carbohydrate-induced laminitis (within 6 hours), suggesting early intervention may be critical to prevent vascular compromise
- •Vascular insufficiency and microthrombi in the hoof are key mechanisms in laminitis development, supporting the importance of therapies targeting blood flow and coagulation
- •Standard coagulation tests may not detect the localized prothrombotic changes occurring in the hoof during early laminitis stages
Key Findings
- •Platelet survival was significantly decreased by 6 hours after carbohydrate administration in laminitis-affected horses compared to controls
- •Marked reduction in blood supply to hooves was evident on arteriography in laminitis-affected horses
- •Microthrombi were identified in venules of the laminar dermis in 2 of 4 affected horses
- •Systemic coagulation activation was not detected, indicating localized rather than systemic prothrombotic changes