Continuous digital hypothermia prevents lamellar failure in the euglycaemic hyperinsulinaemic clamp model of equine laminitis.

This research investigates the impact of continuous digital hypothermia on the development of laminitis, a severe hoof disease in horses. Under the guided conditions of a euglycaemic hyperinsulinaemic clamp model, the research shows that continuous digital hypothermia helped reduce the severity of laminitis and prevented lamellar structural failure.

Study Overview and Methodology

• The study was performed on eight Standardbred horses which were deemed clinically normal. The induction of laminitis in the horses was brought about using the euglycaemic hyperinsulinaemic clamp model (EHC).
• Hypothermia was applied continuously to one of the forelimbs (ICE) following the initiation of the EHC model, with the contralateral limb maintained at ambient temperature (AMB).
• The lamellar sections (proximal, middle, distal) of the dorsal area were harvested and studied 48 hours after the EHC induction.
• The sections were analysed using histological scoring from 0 to 3 and through histomorphometry. They also measured cell proliferation through the counting of epidermal cell nuclei staining positive with an immunohistochemical proliferation marker (TPX2).

Research Findings

• Intense elongation and disruption in the Stratum Externum Lamellatum (SEL) with separation between the dermis and epidermis (a score of 3) was noted in all AMB limbs at one or more section locations. On the other hand, none of these severe symptoms were observed in any of the ICE sections.
• A whopping 92% of the AMB sections received the most severe grade (grade 3), with the remaining 8% at grade 2. In stark contrast, the ICE sections scored only grade 1 (50%) or grade 2 (50%).
• In comparison to the AMB limbs, the ICE sections were 98% less likely to exhibit a grade 2 or 3 score.
• Metrics such as total and nonkeratinised primary epidermal lamellar length significantly increased in AMB limbs compared to ICE. Similarly, TPX2 positive cell counts were significantly higher in AMB limbs than in ICE.

Conclusion

• The application of continuous digital hypothermia began before the detection of laminitis, opening further need for research into its clinical applicability.
• The study nonetheless concludes that continuous digital hypothermia could reduce laminitis severity and forestall compatible histological lesions with lamellar structural failure in the EHC model.