Digital lamellar inflammatory signaling in an experimental model of equine preferential weight bearing.
Authors: Burns Teresa A, Watts Mauria R, Belknap James K, van Eps Andrew W
Journal: Journal of veterinary internal medicine
Summary
# Editorial Summary: Digital Lamellar Inflammatory Signaling in Supporting Limb Laminitis Supporting limb laminitis (SLL)—a devastating complication arising when horses bear weight abnormally due to injury or lameness in the contralateral limb—remains poorly understood at the cellular level, limiting preventative strategies for this often career-ending condition. Burns and colleagues used an experimental model of prolonged unilateral weight bearing in 13 Standardbred horses, applying a weighted shoe to one forefoot for 92 hours in treated animals whilst maintaining unshod controls, then measuring inflammatory markers in digital lamellar tissue using molecular techniques. The supported limb demonstrated significantly elevated messenger RNA for interleukin-6 (IL-6) and cyclooxygenase-2 (COX-2)—roughly 4–3 times higher than control tissue respectively—alongside substantially increased phosphorylated STAT1 and STAT3 proteins, which are key signalling molecules in inflammatory pathways. Notably, other inflammatory markers including IL-1β, IL-10, and COX-1 showed no significant difference, suggesting a selective activation of specific inflammatory cascades rather than generalised tissue inflammation. These findings provide molecular evidence that mechanical overloading triggers discrete inflammatory signalling pathways within the lamellae, offering potential targets for therapeutic intervention and supporting the rationale for aggressive pain management and weight redistribution strategies in at-risk horses.
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Practical Takeaways
- •Prolonged unilateral weight-bearing induces measurable inflammatory signaling in lamellar tissue within 92 hours, suggesting that load redistribution in orthopedic injuries may trigger laminitis through inflammatory pathways rather than mechanical damage alone
- •Farriers and veterinarians managing horses with acute lameness should prioritize pain relief and weight distribution strategies early to minimize inflammatory cascade activation in supporting limbs
- •Supporting limb laminitis may be preventable through aggressive pain management and therapeutic shoeing that encourages more equal weight distribution during recovery from orthopedic injury
Key Findings
- •IL-6 mRNA concentrations were 4-fold higher in support limb lamellar tissue (median 191) compared to contralateral hind limb (median 48; P=0.003)
- •COX-2 mRNA was 3.2-fold higher in support limb tissue (median 400) versus control tissue (median 125; P=0.007)
- •Phosphorylated STAT1 protein was 2.1-fold higher in support limb tissue (0.5) versus controls (0.24; P=0.01)
- •Phosphorylated STAT3 protein was 4.4-fold higher in support limb tissue (1.35) versus controls (0.31; P<0.001)