Ultrafiltration of equine digital lamellar tissue.
Authors: Underwood Claire, Collins Simon N, van Eps Andrew W, Allavena Rachel E, Medina-Torres Carlos E, Pollitt Christopher C
Journal: Veterinary journal (London, England : 1997)
Summary
Understanding drug concentrations within equine lamellar tissue is crucial for developing effective laminitis prevention strategies, yet researchers have lacked practical methods to measure pharmaceutical levels in this critical tissue. Underwood and colleagues developed and validated an ultrafiltration probe technique by first perfecting the placement method in 15 cadaver limbs, then implanting probes into the forelimbs of six living horses to collect lamellar interstitial fluid continuously over 4–14 days. The probes successfully collected ultrafiltrate at a median rate of 55 μL/h (interquartile range 30–63), with fluid production declining significantly from day 3 onwards, whilst the biochemical composition remained stable between days 1 and 4, indicating consistent sampling of the lamellar microenvironment. Horses tolerated the procedure well with no major adverse tissue reactions, establishing this technique as a viable research tool for evaluating whether systemically or locally administered therapeutic agents achieve adequate concentrations within the digital lamellae. For practitioners, this development opens the door to evidence-based advancement of laminitis prevention protocols by enabling researchers to definitively prove whether candidate drugs actually reach therapeutic levels in the tissue where laminitis initiates.
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Practical Takeaways
- •This technique enables veterinarians to measure drug concentrations directly in lamellar tissue, improving ability to evaluate effectiveness of laminitis prevention treatments
- •The method is tolerable in living horses and can sample continuously for extended periods, making it practical for evaluating therapeutic agents during clinical trials
- •Stable ultrafiltrate composition over time suggests the technique provides reliable sampling for pharmacological studies, supporting development of locally-acting laminitis prevention strategies
Key Findings
- •Ultrafiltration probes successfully placed in lamellar tissue of all six living horses with continuous ultrafiltrate collection at 55 μL/h (30-63 μL/h median)
- •Ultrafiltrate production decreased significantly from night 3 onwards (P<0.05) but remained collectable for up to 14 days
- •No significant change in ultrafiltrate constituents between night 1 and night 4 post-implantation (P>0.05), indicating stable sampling conditions
- •Technique was well-tolerated with manageable tissue response, establishing feasibility for measuring lamellar drug concentrations