Isolation of Extracellular Vesicles From the Bronchoalveolar Lavage Fluid of Healthy and Asthmatic Horses.
Authors: Höglund Nina, Koho Ninna, Rossi Heini, Karttunen Jenni, Mustonen Anne-Mari, Nieminen Petteri, Rilla Kirsi, Oikari Sanna, Mykkänen Anna
Journal: Frontiers in veterinary science
Summary
# Editorial Summary: Extracellular Vesicles in Equine Respiratory Disease Extracellular vesicles (EVs)—small membrane-bound particles that mediate inflammatory cell signalling—have emerged as important biomarkers in human and rodent respiratory disease, yet their characterisation in equine bronchoalveolar lavage fluid (BALF) remained unexplored until this 2022 study. Höglund and colleagues developed and validated a protocol for isolating EVs from BALF samples collected via bronchoscopy in 35 asthmatic horses and 19 healthy controls, using size-exclusion chromatography followed by nanoparticle tracking analysis and electron microscopy to quantify and characterise the particles. Both groups demonstrated abundant EV populations (approximately 1.35 × 10¹² particles/mL) with mean diameters around 250 nm and confirmed EV identity through detection of established protein markers (CD63, TSG101, HSP70, EMMPRIN) and hyaluronan association, though no statistically significant differences in EV concentration or size emerged between healthy and asthmatic horses. The successful methodology opens new avenues for investigating whether EV profiling—potentially analysing subpopulation composition, protein cargo or functional properties rather than quantity alone—might serve as a diagnostic or prognostic tool for equine asthma and other airway inflammatory conditions. For practitioners managing horses with suspected lower airway disease, this foundational work suggests future BALF analysis could eventually extend beyond cytology and bacterial culture to include EV characterisation as a non-invasive window into pulmonary inflammation.
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Practical Takeaways
- •This research establishes a reproducible method for studying extracellular vesicles in equine respiratory disease, which may eventually help identify biomarkers for asthma diagnosis or progression.
- •The similarity in EV concentrations between asthmatic and healthy horses suggests future studies need to characterize EV protein composition and function rather than just particle number to understand their role in airway inflammation.
- •For practitioners, this foundational work may lead to improved diagnostic tools for equine asthma in coming years, though clinical applications are not yet available.
Key Findings
- •Extracellular vesicles were successfully isolated from bronchoalveolar lavage fluid using size-exclusion chromatography with mean sizes of 247±35 nm in asthmatic horses and 261±47 nm in healthy controls.
- •Mean EV concentration was 1.38×10¹² particles/mL in asthmatic horses and 1.33×10¹² particles/mL in healthy controls with no statistically significant differences between groups.
- •Isolated EVs were confirmed to associate with multiple EV protein markers (CD63, TSG101, HSP70, EMMPRIN, actin) and hyaluronan using Western blotting and microscopy.
- •Equine bronchoalveolar lavage fluid is rich in EVs of various sizes, establishing a validated protocol for future studies of EV involvement in airway inflammation.