Serial alterations in digital hemodynamics and endothelin-1 immunoreactivity, platelet-neutrophil aggregation, and concentrations of nitric oxide, insulin, and glucose in blood obtained from horses following carbohydrate overload.
Authors: Eades, Stokes, Johnson, LeBlanc, Ganjam, Buff, Moore
Journal: American journal of veterinary research
Summary
# Editorial Summary Understanding the early vascular changes in carbohydrate overload–induced laminitis remains critical for farriers and veterinarians aiming to intervene before clinical signs develop. Eades and colleagues tracked 20 healthy horses over 8–16 hours following carbohydrate overload, collecting blood samples from both digital and jugular sites at hourly (or 4-hourly for haematology) intervals to measure endothelin-1 immunoreactivity, nitric oxide, glucose, insulin, and platelet-neutrophil aggregates alongside digital perfusion parameters. The key findings demonstrated that digital blood endothelin-1 levels rose significantly by 11 hours post-overload and were notably elevated compared with jugular venous levels at 8–12 hours, whilst glucose and insulin concentrations peaked at 3–5 hours, and platelet-neutrophil aggregates increased significantly at 12 hours. These concurrent alterations—particularly the site-specific elevation of endothelin-1 in the digit itself—suggest that endothelial dysfunction is a primary driver of early laminitic pathology rather than a secondary effect, pointing to a therapeutic window in the first 5–12 hours when vascular dysfunction is developing but clinical lameness may not yet be apparent. For practitioners, these findings reinforce the importance of rapid recognition and aggressive management of dietary incidents, as the sequential vascular changes occur well before overt digital inflammation, and suggest that therapies targeting endothelial function may be more effective than those addressing later inflammatory cascades.
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Practical Takeaways
- •Carbohydrate overload triggers measurable endothelial dysfunction and hemodynamic changes within hours; digital tissues show greater ET-1 response than systemic circulation, suggesting localized vascular dysfunction in the hoof
- •Monitoring glucose and insulin spikes in the first 3-5 hours after suspected CHO may help identify high-risk horses; combined with platelet-neutrophil aggregation at 12 hours, these markers could aid early laminitis detection
- •Endothelin antagonist therapy may be a future preventive strategy for CHO-induced laminitis, warranting further investigation into its clinical efficacy and timing of administration
Key Findings
- •Digital blood endothelin-1 immunoreactivity increased significantly at 11 hours post-CHO and was greater in digital versus jugular venous blood at 8, 9, 11, and 12 hours
- •Glucose and insulin concentrations increased significantly from baseline at 3-5 hours post-CHO
- •Platelet-neutrophil aggregates increased significantly at 12 hours post-CHO
- •Concurrent increases in ET-1, insulin, glucose, and platelet-neutrophil aggregates support endothelial dysfunction in CHO-induced laminitis pathogenesis