Effects of endotoxaemia and carbohydrate overload on glucose and insulin dynamics and the development of laminitis in horses.
Authors: Tóth F, Frank N, Chameroy K A, Bostont R C
Journal: Equine veterinary journal
Summary
# Editorial Summary Insulin resistance and systemic inflammation are recognised triggers for laminitis in horses, yet the precise mechanisms linking carbohydrate overload to clinical disease remain incompletely understood. Tóth and colleagues investigated whether pre-existing endotoxaemia (induced via lipopolysaccharide infusion) would exacerbate the metabolic derangements caused by carbohydrate overload in 24 horses divided into three treatment groups: endotoxin alone, oligofructose overload alone, or sequential endotoxin followed by oligofructose 16 hours later. All treatments significantly reduced insulin sensitivity and induced systemic inflammatory signs, though the combined endotoxin/oligofructose protocol elicited a pronounced hyperinsulinaemic response to an intravenous glucose challenge and resulted in the highest laminitis incidence—five of eight horses developed clinical laminitis compared with zero to two cases in single-treatment groups. These findings suggest that endotoxaemia and carbohydrate overload operate through broadly similar mechanisms to impair glucose metabolism, but their sequential application creates a synergistic effect that substantially elevates laminitis risk. For practitioners managing horses prone to pasture-associated laminitis or those recovering from systemic infections, these results underscore the critical importance of preventing carbohydrate overload during periods when insulin sensitivity is already compromised, and support careful dietary management as a cornerstone of laminitis prevention strategies.
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Practical Takeaways
- •Horses with concurrent endotoxaemia and carbohydrate overload face dramatically elevated laminitis risk (5/8 affected); monitor closely during illness if pasture access or grain availability is unrestricted.
- •Insulin sensitivity decreases after carbohydrate overload regardless of endotoxin exposure, supporting strict carbohydrate restriction in laminitis-prone horses and during systemic illness.
- •Systemic inflammation from either endotoxin or carbohydrate overload alone increases laminitis susceptibility; the combination is synergistic and particularly dangerous.
Key Findings
- •Five horses in the LPS/OF group developed clinical laminitis compared with 0 in LPS-only and 2 in OF-only groups, demonstrating that endotoxin pretreatment combined with carbohydrate overload significantly increases laminitis risk.
- •Insulin sensitivity decreased significantly (P < 0.001) over time in all groups, with treatment x time effects detected for acute insulin response to glucose (P = 0.038).
- •Endotoxin pretreatment did not significantly alter the glucose metabolism responses induced by carbohydrate overload alone.
- •Both LPS and oligofructose induced clinical signs consistent with systemic inflammation and leucopenia occurred in LPS-treated horses.