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The role of alveolar macrophages in the pathogenesis of recurrent airway obstruction in horses.
Abstract: When challenged with allergens and pro-inflammatory agents, such as Aspergillus fumigatus (AF), hay dust solution (HDS) and lipopolysaccharide (LPS), the innate immune response will not only activate the immune system but also increase the amount of pro-inflammatory cytokines in the bronchoalveolar space. The aim of this study was to assess the response of equine alveolar macrophages to different aerosolized challenges and to investigate the differences in this response between horses susceptible or nonsusceptible to recurrent airway obstruction (RAO). Seven susceptible and 5 nonsusceptible horses were challenged with saline, LPS, HDS, or AF, and bronchoalveolar lavage (BAL) cytology, total cell counts, and lung function were assessed. In addition, alveolar macrophages were isolated 6 and 24 hours after challenge, and macrophage mRNA expression of tumor necrosis factor (TNF)-alpha and interleukins (IL) IL-1beta, IL-6, IL-8, and IL-10 were measured by means of real-time (RT) polymerase chain reaction (PCR). There was a significant difference in lung function, neutrophil ratios, and total cell counts in the bronchoalveolar lavage fluid between RAO-susceptible and nonsusceptible horses. In addition, the expression of TNF-alpha, IL-1beta, and IL-8 by alveolar macrophages after challenges were higher in susceptible horses, than in nonsusceptible horses. In contrast, I1-6, considered an anti-inflammatory cytokine, showed a higher expression in nonsusceptible horses 6 hours after inhalation challenge with allergens and pro-inflammatory antigens. These data suggest that the differences between susceptible and nonsusceptible horses to RAO are not only dependent on adaptive immunity but also start with an innate immune response.
Publication Date: 2006-02-25 PubMed ID: 16496937DOI: 10.1892/0891-6640(2006)20[167:troami]2.0.co;2Google Scholar: Lookup The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
- Alveolar Macrophages
- Aspergillus
- Bronchoalveolar Lavage
- Cytokines
- Equine Health
- Horses
- Immune Response
- Immune System
- Immunity
- Inflammation
- Inflammatory Response
- Interleukins
- Lipopolysaccharide
- Lung Health
- Pathogenesis
- Real-Time PCR
- Recurrent Airway Obstruction
- Respiratory Disease
- Tumor Necrosis Factor
- Veterinary Medicine
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
This research study seeks to understand the role that alveolar macrophages in horses play in recurrent airway obstruction (RAO). By examining horses that are susceptible or nonsusceptible to RAO, the authors found that the susceptibility might be linked to the way the horses’ immune systems respond to allergens and certain pro-inflammatory agents.
Objective
The study aimed to examine how equine alveolar macrophages responded to various aerosolized challenges. Specifically, the researchers wanted to identify any differences in response between horses that were susceptible to RAO and those that were not.
Methodology
- Twelve horses were involved in the study – seven being susceptible to RAO and five not.
- The horses were exposed to different aerosolized substances such as hay dust solution (HDS), Aspergillus fumigatus (AF), saline, and lipopolysaccharide (LPS).
- After exposure to these agents, bronchoalveolar lavage (BAL) cytology, total cell counts, and lung function examinations were conducted.
- Alveolar macrophages were isolated 6 and 24 hours post-exposure, and the mRNA expression of several inflammatory agents were measured through real-time polymerase chain reaction (PCR).
Findings
- There was a notable difference in lung function, neutrophil ratios, and total cell counts in the BAL fluid between RAO-susceptible and nonsusceptible horses.
- The susceptible horses exhibited a higher expression of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, and IL-8 in their alveolar macrophages.
- Nonsusceptible horses showed a higher expression of anti-inflammatory cytokine IL-6, about 6 hours after exposure to the allergens and pro-inflammatory agents.
Conclusion
The study results suggest that the differences seen in horses between RAO susceptibility could be because of their innate immune response to allergens and pro-inflammatory agents, rather than just relying on an adaptive immunity theory. This indicates that the role of alveolar macrophages in RAO pathogenesis is essential and needs further exploration in the future.
Cite This Article
APA
Laan TT, Bull S, Pirie R, Fink-Gremmels J.
(2006).
The role of alveolar macrophages in the pathogenesis of recurrent airway obstruction in horses.
J Vet Intern Med, 20(1), 167-174.
https://doi.org/10.1892/0891-6640(2006)20[167:troami]2.0.co;2 Publication
Researcher Affiliations
- Department of Equine Science, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands. t.laan@delinge.hoeve.nl
MeSH Terms
- Animals
- Antigens, Fungal / pharmacology
- Aspergillus fumigatus
- Bronchoalveolar Lavage Fluid / cytology
- Cytokines / metabolism
- Dust
- Female
- Gene Expression Regulation
- Horse Diseases / pathology
- Horse Diseases / physiopathology
- Horses
- Lipopolysaccharides / pharmacology
- Lung Diseases, Obstructive / chemically induced
- Lung Diseases, Obstructive / physiopathology
- Lung Diseases, Obstructive / veterinary
- Macrophages, Alveolar / metabolism
- Male
Citations
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- Morini M, Peli A, Rinnovati R, Magazzù G, Romagnoli N, Spadari A, Pietra M. Immunohistochemical Expression of Neurokinin-A and Interleukin-8 in the Bronchial Epithelium of Horses with Severe Equine Asthma Syndrome during Asymptomatic, Exacerbation, and Remission Phase. Animals (Basel) 2021 May 12;11(5).
- Hue E, Orard M, Toquet MP, Depecker M, Couroucé A, Pronost S, Paillot R, Richard EA. Asymmetrical Pulmonary Cytokine Profiles Are Linked to Bronchoalveolar Lavage Fluid Cytology of Horses With Mild Airway Neutrophilia. Front Vet Sci 2020;7:226.
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