Lamellar perfusion and energy metabolism in a preferential weight bearing model.
Authors: van Eps Andrew W, Belknap James K, Schneider Xavier, Stefanovski Darko, Engiles Julie B, Richardson Dean W, Zedler Steven T, Medina-Torres Carlos E, Watts Mauria R
Journal: Equine veterinary journal
Summary
# Editorial Summary: Lamellar Perfusion and Energy Metabolism in Preferential Weight Bearing Supporting limb laminitis remains a significant clinical challenge, with compromised blood flow to the lamellae suspected as a key mechanism, yet direct evidence linking mechanical overload to lamellar ischaemia has been limited. Van Eps and colleagues used microdialysis probes implanted in the lamellar tissue of 13 horses to measure real-time changes in glucose, lactate, and pyruvate levels over 92 hours, comparing six horses subjected to increased loading on one forelimb via platform shoe against seven unloaded controls, whilst continuously logging weight distribution. The overloaded group demonstrated marked lamellar ischaemia: glucose availability declined steeply, lactate-to-pyruvate ratios surged to 196 (compared to just 42 in controls), and tissue perfusion (measured by urea clearance) deteriorated significantly, whilst control horses actively shifted weight away from instrumented limbs and showed no such metabolic derangement. Notably, these ischaemic changes were confined to the lamellar dermis itself; deeper sublamellar tissue remained unaffected, suggesting a site-specific vascular compromise rather than global limb perfusion failure. For practitioners managing laminitis cases, these findings provide mechanistic support for weight redistribution strategies and highlight that sustained abnormal loading directly triggers energy crisis within the sensitive lamellae—underscoring the critical importance of early intervention and pain management to restore normal weight-bearing patterns before irreversible tissue damage occurs.
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Practical Takeaways
- •Sustained preferential loading of one forelimb (>38% bodyweight) induces measurable lamellar ischaemia within 92 hours, supporting the mechanical load theory of supporting limb laminitis
- •Farriers and veterinarians should recognize that platform shoes or weight redistribution devices may need close monitoring for signs of laminitis in the overloaded limb
- •This model demonstrates that lamellar ischaemia develops as a direct consequence of increased mechanical load, providing a mechanistic basis for prophylactic management of horses at risk of contralateral limb laminitis
Key Findings
- •Lamellar glucose decreased faster in PWB horses (38.7% bwt load) compared to controls at 27.3% bwt load (P=0.007)
- •Lamellar lactate:pyruvate ratio increased significantly in PWB group, peaking at 196 [79-656] versus 42 [41-49] in controls (P<0.001)
- •Lamellar urea clearance (perfusion marker) decreased only in PWB group (P<0.001), indicating ischaemia
- •Evidence of lamellar ischaemia was confined to the lamellar dermis and absent in sublamellar tissues in PWB-loaded limbs