Assistant Professor of Large Animal Medicine University of Pennsylvania - New Bolton Center Kennett Square, PA, United States
Abstract:
Background: Total adiponectin is a marker of insulin dysregulation and laminitis risk. The reliability of the currently available immunoturbidometric total adiponectin (TA) assay, as well as natural TA variation, has not been established in equids. Hypothesis/
Objectives: 1) Determine markers of analytic validity for the TA assay; 2) Assess correlation between TA and high molecular weight adiponectin (HMWA); 3) Investigate variability of TA throughout the course of a day. Animals: Serum samples from 207 client- and university-owned mixed breed horses, ponies, and donkeys with and without insulin dysregulation.
Methods: Total adiponectin concentrations were determined using a turbidimetric immunoassay. Intra- and inter-assay variability and recovery upon dilution were assessed. HMW adiponectin was measured using a previously-validated ELISA. Spearman correlation was performed to assess the relationship between TA and HMWA. TA was measured every 2 hours in 5 horses over a 24-hour period.
Results: Mean (range) intra-assay coefficient of variation (CV%) was 2.4% (1.1-5.6%), and inter-assay CV% was 16.3% (11.3-21.8%). Recovery upon dilution was 121.9% (75-140.6%). A strong correlation between TA and HMWA was observed (Spearman's ρ = 0.90 [95%CI: 0.86-0.92], p < 0.001). Mean (range) within-horse CV% for TA over 24 hours was 10.4% (5.6 – 22.6%). Conclusion and Clinical Importance: The turbidimetric immunoassay was sufficiently precise and reliable for measurement of TA in equids. TA correlated well with HMWA in this population. The variation in TA over 24 hours in individual horses was likely insufficient to affect clinical interpretation, although more research in this area is warranted.
