(E57) Decreased Adiponectin and Increased Leptin: Adiponectin are Associated with Insulin Dysregulation and Laminitis in Light-breed Horses

Abstract:

Background: Associations between hypoadiponectinemia, insulin dysregulation (ID) and laminitis risk have been established in ponies, but not horses. Leptin:adiponectin (L/A) is a potentially useful marker of ID and laminitis risk.
Hypothesis/

Objectives: We hypothesized that light-breed horses with ID and/or pre-existing laminitis would have lower serum adiponectin and increased L/A compared to healthy horses.
Animals: 410 client- and university-owned mixed light-breed horses.

Methods: Cross-sectional cohort study. Resting serum total adiponectin, leptin and insulin concentrations (unfasted) were measured in all horses. Oral sugar tests (OST, 0.15ml/kg Karo syrup; n=181) and forefoot radiographs (n=137) were performed in a subset. Adiponectin, leptin and L/A were compared between horses with ID (resting or OST insulin >30µIU/ml; n=320) and non-ID horses (OST insulin < 30µIU/ml; n=90); and laminitic (>2 degree radiographic distal phalangeal rotation; n=56) vs non-laminitic horses (n=81) using Mann-Whitney tests.

Results: Median [interquartile range] serum total adiponectin (µg/ml) was lower (p < 0.001) in horses with ID (6.3 [4.8-8.8]) vs non-ID (8.3 [6.6-11.2]) and in laminitic (5.8 [3.6-8.4]) vs non-laminitic (8.1 [6.4-10.3]) horses. Leptin (ng/ml) was higher (p < 0.001) in ID (13.8 [8.3-17.3]) vs non-ID horses (5 [2.3-8.7]), but was not different between laminitic (10.1 [5.9-17.2]) and non-laminitic horses (10.1 [4-15.4]); p=0.44. L/A ratio was higher (p < 0.001) in horses with ID (1.9 [1.2-2.7]) vs non-ID (0.5 [0.2-1.2]) and in laminitic (1.9 [1.2-3.3]) vs non-laminitic (0.96 [0.4-1.9]) horses.
Conclusion and Clinical Importance: Resting adiponectin and L/A ratio are potentially useful markers of metabolic health in light-breed horses. Associations between adiponectin and laminitis warrant further investigation.