Validity and application of immunoturbidimetric and enzyme-linked immunosorbent assays for the measurement of adiponectin concentration in ponies.
Authors: Menzies-Gow N J, Knowles E J, Rogers I, Rendle D I
Journal: Equine veterinary journal
Summary
# Editorial Summary Adiponectin, an adipokine with anti-inflammatory and insulin-sensitising properties, has emerged as a potential biomarker for endocrinopathic laminitis risk, yet earlier research utilised assays that are no longer available or validated. Menzies-Gow and colleagues evaluated the analytical performance of immunoturbidimetric (IT) and ELISA methods for measuring total and high molecular weight adiponectin in ponies, comparing results against a previously validated radioimmunoassay in a cohort of 223 nonlaminitic animals and smaller groups of previously laminitic ponies. The IT assay demonstrated good precision and strong agreement with the reference method, revealing significantly lower total adiponectin concentrations in ponies with prior laminitis (8.9 µg/mL versus 24.2 µg/mL in controls, P<0.01) and notably, in clinically normal ponies that subsequently developed laminitis within 12 months (median 4.8 µg/mL versus 19.9 µg/mL in those remaining sound). Using ROC curve analysis, adiponectin concentration showed good discriminatory accuracy (0.76) for predicting laminitis development, though the ELISA methods failed validation and cannot be recommended. For practitioners, these findings strengthen the case for adiponectin as a clinically useful risk indicator in susceptible populations, though measurement via IT assay rather than ELISA, and recognition that laminitis risk stratification data derive from a geographically limited cohort, warrant consideration in application.
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Practical Takeaways
- •Low circulating adiponectin levels measured via IT assay are associated with both previous laminitis and future laminitis risk in ponies, potentially offering a useful biomarker for risk stratification
- •If considering adiponectin testing for laminitis risk assessment, use immunoturbidimetric assays only—ELISA methods are not reliable for equine measurement
- •Ponies with adiponectin <5 μg/mL are at significantly elevated risk of developing laminitis within the next year, warranting enhanced management and preventive strategies
Key Findings
- •Immunoturbidimetric (IT) assay is precise and valid for measuring equine total adiponectin concentration (TAC), with good agreement to radioimmunoassay
- •TAC was significantly lower in previously laminitic ponies (8.9 ± 2.9 μg/mL) compared to never laminitic ponies (24.2 ± 11.8 μg/mL, P<0.01)
- •Never laminitic ponies that developed laminitis within 12 months had significantly lower TAC (median 4.8 μg/mL) than those remaining nonlaminitic (19.9 μg/mL, P<0.01)
- •TAC demonstrated good accuracy (AUC 0.76) for distinguishing ponies that would or would not develop laminitis within 12 months
- •ELISA methods failed validation and are not suitable for measuring equine TAC or HMW adiponectin