Endocrinopathic laminitis in the horse
Authors: Johnson Philip J., Messer Nat T., Slight Simon H., Wiedmeyer Charles, Buff Preston, Ganjam Venkataseshu K.
Journal: Clinical Techniques in Equine Practice
Summary
# Editorial Summary: Endocrinopathic Laminitis in the Horse Chronic hyperinsulinaemia is implicated in endocrinopathic laminitis, yet current management relies solely on analgesia rather than addressing the underlying metabolic driver. The prevailing hypothesis suggests that prolonged insulin exposure triggers laminar pathology via insulin-like growth factor-1 receptors (IGF-1R) rather than classical insulin receptors, which are sparse in lamellar tissue; Johnson and colleagues investigated this mechanism by screening four human-derived anti-IGF-1R monoclonal antibodies for cross-reactivity with equine receptors using soluble receptor preparations, ELISA, flow cytometry, and radioligand binding assays on lamellar and hepatic tissue. Only one antibody (mAb1) successfully competed with IGF-1 for binding at equine lamellar IGF-1R with an inhibitory concentration of 5–159 ng/mL, whilst none blocked equine hepatic insulin receptors, confirming tissue-selective receptor expression patterns. These findings provide the structural and functional basis for developing an equine-specific therapeutic monoclonal antibody that could potentially interrupt the hyperinsulinaemia–laminitis cascade, representing a significant departure from symptomatic management towards causal intervention in metabolically predisposed horses.
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Practical Takeaways
- •Endocrinopathic laminitis remains a significant clinical problem with limited treatment options; understanding the IGF-1R mechanism may lead to new therapeutic strategies beyond pain relief
- •Managing hyperinsulinemia through diet and weight control is crucial, as pharmacologic alternatives targeting the IGF-1R pathway are still in early development
- •This research represents foundational work toward novel monoclonal antibody therapy; practitioners should monitor for future clinical trials of anti-IGF-1R treatments
Key Findings
- •Prolonged hyperinsulinemia is implicated as the cause of equine endocrinopathic laminitis, with no current pharmacologic treatments available beyond pain management
- •Insulin likely exerts effects on lamellae via IGF-1 receptors (abundant in lamellar tissue) rather than insulin receptors (scarce in this tissue)
- •One human anti-IGF-1R monoclonal antibody (mAb1) demonstrated effective competition with IGF-1 for binding to equine lamellar tissue receptors (IC50 5-159 ng/mL)
- •The identified mAb1 prototype is suitable for further development as a potential therapeutic agent for endocrinopathic laminitis