Extracellular vesicles, hyaluronic acid, and fatty acids in equine asthma

Equine asthma (EA) is an inflammatory condition of the lower airways that causes chronic respiratory dysfunction with varying degrees of severity. Recurrent episodes of bronchoconstriction and mucus accumulation in the airways lead to thickening of the airway walls. Horses with EA exhibit reduced respiratory capacity during exercise, and in severe cases, even at rest. A deeper understanding of EA’s molecular pathways is essential for developing biomarkers and treatments. Extracellular vesicles (EVs) are membrane-bound particles that participate in cell-to-cell communication. EVs transport biomolecules such as proteins, fatty acids, and hyaluronic acid (HA), influencing inflammation. EVs can mediate both favorable anti-inflammatory and unfavorable pro-inflammatory actions. Fatty acids serve as structural components for cells and EVs, and they are also precursors for inflammatory mediators. Lipid mediators play a vital role in inflammation and regulate the transition between the acute and resolution phases of inflammation. Similarly, HA, which can be carried by EVs, is involved in both inflammation and the maintenance of tissue health. Studying EVs, fatty acids, and HA together in the context of EA provides new insight into the complex molecular and cellular interactions in EA. This thesis examined EVs, fatty acids, HA, and airway remodeling in EA. The study confirmed the presence of EVs in bronchoalveolar lavage fluid (BALF) but found no significant differences in size or concentration between EA and control horses. Fatty acid profiles differed between horses with EA and control horses, but these profiles could not be used as diagnostic markers. In EVs, the proportion of palmitic acid (16:0) decreased, while that of eicosapentaenoic acid (20:5n-3) increased in horses with severe EA. In all sample types, the proportion of dihomo-γ-linolenic acid (20:3n-6) was elevated in horses with EA compared to controls. The study also revealed increased HA levels in BALF from EA horses. Additionally, severe EA was associated with airway remodeling. This research provides novel insights into the molecular interactions in EA, demonstrating that EVs, fatty acids, and HA contribute to airway inflammation and remodeling. Understanding these mechanisms advances clinical research in both veterinary and human asthma contexts.

Grantor dc:publisher

Helsingin yliopisto

Year dc:date.issued

2025

Author dc:creator

• Höglund-Granfelt, Nina

• veterinary medicine

Statement dc:rights

• This publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited.
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Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/10138/592260

OAI record oai:identifier

https://helda.helsinki.fi/server/oai/request?verb=GetRecord&metadataPrefix=dim&identifier=oai%3Ahelda.helsinki.fi%3A10138%2F592260