Analysis of lipid mediator profiles in the blood of horses with equine asthma using UPLC-MS/MS.

Overview

• This study analyzed lipid mediators in the blood of horses with equine asthma using advanced mass spectrometry techniques.
• The research aims to better understand the role of inflammation-related lipids in equine asthma and their relevance as a model for human asthma.

Background and Significance

• Equine asthma (EA) is a chronic inflammatory disease affecting the lower respiratory tract of horses.
• EA is primarily triggered by environmental factors such as dusty hay.
• The disease is increasingly used as an animal model for studying human asthma because of similar pathological features.
• Previous EA research focused mainly on cellular and cytokine involvement in inflammation.
• However, the role of lipid mediators (LMs), which regulate inflammation, is less understood in this context.

Lipid Mediators and Their Classification

• Lipid mediators are bioactive lipids that influence inflammatory processes in the body.
• They are broadly categorized into:
  • Pro-inflammatory LMs derived from arachidonic acid (AA), including leukotrienes (LTs) and prostaglandins (PGs).
  • Inflammation-resolving LMs derived from omega-3 fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

Methodology

• Targeted metabololipidomics was used, employing advanced ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).
• Samples consisted of serum and stimulated whole blood.
• The study involved 30 healthy horses and 30 horses diagnosed with equine asthma.
• This approach enabled precise quantification and profiling of various lipid mediators in the blood.

Key Findings

• There was considerable individual variability in free fatty acid levels and their metabolic profiles among horses.
• No significant differences in lipid mediator profiles were observed between healthy horses and those with equine asthma.
• This lack of significant difference highlights the complex nature and multifactorial pathogenesis of equine respiratory disease.
• The most abundant lipid mediator detected was 12-hydroxyeicosatetraenoic acid (12-HETE) in both serum and stimulated whole blood.
• Additionally, lipid mediator levels tended to decrease with increasing age of the horses.

Implications and Conclusions

• This study offers the first comprehensive profiling of lipid mediators in the blood of horses with and without equine asthma.
• The findings contribute to a better understanding of the inflammatory lipid environment in EA, although direct disease-specific biomarkers were not found.
• The results underscore the complexity of equine asthma pathogenesis and possible influences such as age and individual variation.
• The lipid mediator profiles generated could serve as a valuable reference for future comparative studies between equine and human asthma.
• This research supports the use of EA as a translational model to gain insights into lipid mediator-driven inflammation in human asthma.