Ex vivo effects of insulin on the structural integrity of equine digital lamellae.
Authors: Sandow C, Fugler L A, Leise B, Riggs L, Monroe W T, Totaro N, Belknap J, Eades S
Journal: Equine veterinary journal
Summary
# Editorial Summary Endocrinopathic laminitis remains the leading form of the disease in horses, typically driven by hyperinsulinaemia secondary to metabolic dysfunction. Sandow and colleagues used an ex vivo biomechanical model to test whether elevated insulin directly compromises lamellar structural integrity, isolating this variable from the systemic inflammatory cascade that complicates in vivo studies. Fresh lamellar explants from clinically normal horses were subjected to either control medium or insulin-supplemented medium (2.5 µg/ml) for 8 hours before tensile testing to measure load at failure, stress, elongation, and Young's modulus. Insulin-treated explants demonstrated significantly impaired mechanical properties: they failed at lower loads (P = 0.0001), lower stress (P = 0.001), and exhibited greater elongation before failure (P = 0.02), indicating reduced stiffness and premature structural compromise. This work establishes a reproducible ex vivo platform for investigating the direct effects of hyperinsulinaemia on lamellar mechanics and has immediate implications for understanding why metabolic horses progress to laminitis; the findings suggest that insulin itself contributes to lamellar weakness independent of vascular or inflammatory mechanisms, potentially informing prevention strategies centred on aggressive insulin management in at-risk individuals.
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Practical Takeaways
- •Hyperinsulinaemia directly compromises lamellar strength in susceptible horses; aggressive metabolic management and insulin control are critical for laminitis prevention in endocrinopathic cases
- •Horses with underlying metabolic disorders require early identification and treatment to prevent irreversible lamellar damage, as insulin itself appears to be a causative factor rather than just a marker of disease
- •This research provides a foundation for testing therapeutic interventions targeting insulin signaling pathways as potential preventive strategies for endocrinopathic laminitis
Key Findings
- •Insulin-treated lamellar explants failed at significantly lower load (P = 0.0001) compared to controls
- •Insulin-treated explants demonstrated lower stress at failure (P = 0.001) and greater elongation to failure (P = 0.02)
- •An ex vivo model was successfully established for evaluating hyperinsulinaemia-induced lamellar failure
- •Insulin weakens structural integrity of equine digital lamellae at 2.5 μg/ml concentration after 8 hours exposure