Abnormalities in lung surfactant in horses clinically affected with recurrent airway obstruction (RAO).
Authors: Christmann U, Welles E G, Waldridge B M, Schumacher J, Grier B L, Hite R D
Journal: Journal of veterinary internal medicine
Summary
# Abnormalities in Lung Surfactant in Horses Clinically Affected with Recurrent Airway Obstruction Whilst surfactant dysfunction is well established in human asthma and other respiratory diseases, its role in equine recurrent airway obstruction (RAO) has remained largely unexplored. Christmann and colleagues collected bronchoalveolar lavage fluid from six healthy horses and five RAO-affected horses, then used ultracentrifugation and high-performance liquid chromatography to analyse phospholipid composition and surface tension properties of the surfactant fractions. RAO-affected horses demonstrated markedly reduced total phospholipid content (median 23.2 versus 172 µg/mL in healthy controls), significantly lower phosphatidylglycerol percentages (4.5% versus 6.6%), and an abnormally elevated phosphatidylcholine-to-phosphatidylglycerol ratio (20.9 versus 13.9). These findings suggest that RAO may involve surfactant dysfunction similar to human asthma, potentially contributing to increased bronchoconstriction and impaired airway clearance—mechanisms that warrant investigation in larger studies to determine whether surfactant supplementation or modification could offer therapeutic benefit for affected horses.
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Practical Takeaways
- •RAO involves measurable abnormalities in lung surfactant composition, suggesting a biochemical basis for airway dysfunction beyond simple inflammation
- •Surfactant deficiency in RAO-affected horses may explain their increased susceptibility to bronchoconstriction and difficulty clearing secretions during episodes
- •This finding opens potential therapeutic avenues (surfactant supplementation) that warrant further investigation for clinical application in RAO management
Key Findings
- •RAO-affected horses had significantly decreased phospholipid content in total surfactant (23.2 vs 172 µg/mL, P=0.0062) compared to healthy horses
- •Phosphatidylglycerol percentage was significantly lower in RAO horses (4.5% vs 6.6%, P=0.028)
- •Phosphatidylcholine to phosphatidylglycerol ratio was significantly higher in RAO-affected horses (20.9 vs 13.9, P=0.045)
- •Lung surfactant abnormalities in RAO horses may contribute to bronchoconstriction and impaired mucus clearance