Paraoxonase-1 activity evaluation as a diagnostic and prognostic marker in horses and foals.
Authors: Ruggerone Beatrice, Paltrinieri Saverio, Giordano Alessia, Scavone Donatella, Nocera Irene, Rinnovati Riccardo, Spadari Alessandro, Scacco Licia, Pratelli Paola, Sgorbini Micaela
Journal: Journal of veterinary internal medicine
Summary
# Editorial Summary: Paraoxonase-1 as a Clinical Marker in Equine Practice Paraoxonase-1 (PON-1), an antioxidant enzyme that declines during inflammatory states and oxidative stress, has recently been validated for measurement in equine blood but remains unproven as a clinical diagnostic tool. Ruggerone and colleagues evaluated 172 blood samples from 58 hospitalised horses across three veterinary centres, measuring PON-1 activity on admission and at 24-hourly intervals, then stratifying results by systemic inflammatory response syndrome (SIRS) status and clinical outcome. Whilst no significant PON-1 differences emerged between SIRS-positive and SIRS-negative horses overall, mares with SIRS demonstrated significantly reduced activity; more importantly, low PON-1 activity at admission carried a likelihood ratio of 2.40–3.89 times higher for mortality than survival, despite low sensitivity (0–46.2%) and high specificity (87–100%) for predicting adverse outcomes. Serial PON-1 measurements during treatment did not predict prognosis, suggesting that initial assessment—rather than trending—holds clinical value. For practitioners, PON-1 activity warrants further investigation as a prognostic aid in acutely ill horses, particularly when results fall below threshold at presentation, though it should complement rather than replace existing inflammatory markers and clinical judgment in predicting patient outcomes.
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Practical Takeaways
- •Low PON-1 activity on admission may help identify high-risk horses with poor prognosis, but cannot rule out SIRS or complications due to low sensitivity
- •PON-1 measurement is not useful for monitoring treatment response or predicting outcome during hospitalization
- •Consider PON-1 as a supportive prognostic tool only in conjunction with other clinical and laboratory indicators
Key Findings
- •PON-1 activity showed low sensitivity (0.0%-46.2%) but high specificity (87.0%-100.0%) for identifying SIRS-positive horses or poor prognosis
- •Low PON-1 activity at admission increased likelihood of death by 2.40-3.89 times compared to survival
- •Significant difference in PON-1 between SIRS and non-SIRS cases was only found in mares (P = .05)
- •Repeated PON-1 measurements after treatment did not predict outcome