Temporal regulation of cytokine mRNA expression in equine recurrent airway obstruction

Department of Veterinary Science, Maxwell Gluck Equine Research Center, University of Kentucky, Lexington, KY 40546-0099, USA.
Veterinary Immunology and Immunopathology (Impact Factor: 1.54). 11/2005; 108(1-2):237-45. DOI: 10.1016/j.vetimm.2005.07.013
Source: PubMed


Acute and chronic inflammation of the airway remains an important health problem for equids. "Heaves" or recurrent airway obstruction (RAO) remains one of the most commonly diagnosed conditions affecting the lung of older horses in Europe and the United States. The typical clinical signs of RAO include non-productive coughing, serous nasal discharge, labored expiratory effort, and flaring of the nostrils. Auscultation of the lungs of the affected horse often reveals abnormal respiratory sounds, described as crackles and wheezes, throughout the area of the lung field. These clinical signs occur secondary to an inflammatory response that results in bronchospasm, excessive mucus production and airway obstruction. This inflammatory response is characterized by the presence of excessive mucus and inflammatory cells, primarily neutrophils, in the small airways. Most evidence suggests that RAO is the result of a pulmonary hypersensitivity to inhaled antigens. Exposure of affected horses to hay dust, pollens, and mold spores leads to neutrophil accumulation in the lung and bronchospasm. The identification of allergen-specific IgE in bronchoalveolar lavage (BAL) fluid and sera of affected horses supports the involvement of a late phase, IgE-mediated, hypersensitivity reaction in the pathogenesis of equine RAO. The production of IgE antibodies is regulated by the cytokines IL-4 and IL-13. Using a quantitative PCR method we have reported that horses with RAO exhibit a modified Type 2 cytokine response characterized by the production of IL-4 and IL-13 mRNA, but not IL-5 mRNA in BAL cells. Interferon-gamma mRNA was also elevated, suggesting a mixed response. While these results are consistent with equine RAO being the result of an aberrant Type 2 cytokine response to inhaled allergens, others have failed to find any evidence of elevated Type 2 cytokine mRNA in BAL from horses with "heaves". It is likely that these disparate results could be the result of differences in the clinical stage of the affected animals or the timing of sample collection. Here, we report a diverse pattern of cytokine gene expression when sampling a group of affected horses over a period of time.

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Available from: Ralph E Beadle, Sep 21, 2014
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    • "S. Hansen et al. / Veterinary Immunology and Immunopathology 158 (2014) 238–243 239 cytokines including interferon (IL)-4, IL-5 and IL-13, and a concomitant decrease in Th1 associated cytokines namely interferon gamma (IFN-␥) (Cordeau et al., 2004; Kleiber et al., 2005; Lavoie et al., 2001). Conflicting results have been reported with an increase in Th1 associated cytokines alone, or in combination with Th2 associated cytokines (Ainsworth et al., 2003; Beadle et al., 2002; Giguere et al., 2002; Horohov et al., 2005). Also, other studies have suggested a Th17 pathway (Ainsworth et al., 2006; Debrue et al., 2005). "
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    ABSTRACT: An imbalance in various cytokine mRNA expression in bronchoalveolar lavage (BAL) and peripheral blood mononuclear cells (PBMC) in horses suffering from recurrent airway obstruction (RAO) has been demonstrated; however, the natural variation of cytokine expression in healthy horses has yet to be described. The objectives of this study were to: 1) identify age-related differences in the expression of pro-inflammatory cytokines in BAL and PBMC, 2) compare the expression of pro-inflammatory cytokines between BAL and PBMC, 3) evaluate the relationship between BAL pro-inflammatory cytokine expression and BAL cytology. Cells from BAL and PBMC were collected from 66 horses and stimulated with LPS and PGN. The expression of IL-1β, IL-6, IL-8, TNF-α and TLR-4 were measured using qPCR. A significant age-related decrease for IL-1β and IL-8 in BAL, significant difference in cytokine mRNA expressions between BAL and PBMC and a significant relationship between TLR-4, IL-8 in LPS stimulated BAL samples and the percentage of neutrophils in BAL cytology were found. In conclusion, the natural age-related decrease in pro-inflammatory cytokine expression in BAL is new knowledge; this in contrast to other age-related findings associated with PBMC, where pro-inflammatory cytokines are known to increase with age in both horses and humans, the phenomenon known as ‘inflamm-aging’
    Veterinary Immunology and Immunopathology 04/2014; 158(3-4). DOI:10.1016/j.vetimm.2014.02.001 · 1.54 Impact Factor
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    • "The pathogenesis of RAO is complex; environmental antigens induce airway inflammation, migration of PMN cells to the bronchioalveolar space and a Th2 adaptive immune response with production of IgE and IgG antibodies . Whereas IgE is known to be responsible for triggering type I hypersensitivity in affected airways (Eder et al., 2000; Halliwell et al., 1993; Horohov et al., 2005; Moran et al., 2012), IgG triggers a type III hypersensitivity response that activates the production of proinflammatory factors such as C–X–C chemokines that stimulate PMN migration into the affected area (Lavoie-Lamoureux et al., 2010; Lavoie et al., 2001). One of the most common allergens responsible for RAO in horses is A. fumigatus, which is known to damage epithelial structures via the production of elastase, protease, catalase, dismutase, and cytotoxic ribonuclease (Purkayastha et al., 2000). "
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    ABSTRACT: Recurrent airway obstruction (RAO) is an equine immune-mediated disease with a high incidence worldwide. The aim of this work was to contribute to the understanding of RAO pathogenesis by studying T cells bearing regulatory markers in peripheral blood (PB) and in bronchoalveolar lavage fluid (BALF) recovered from the same group of susceptible horses before and after exposure tomouldy hay, which has been shown to induce RAO signology in our horse herd. With this purpose, mononuclear cells were obtained from the BALF and PB from horses before and after antigenic challenge and were stained with fluorochrome-conjugated antibodies against CD4, CD25 and Foxp3 and subsequently analyzed by flow cytometry. The results indicated that the percentage of CD4+, Foxp3+ cells clearly increased in PB and BALF obtained from horses with RAO. In addition, the percentage of CD4+, CD25high cells was greatly augmented in BALF of RAO positive horses compared with a baseline. No changes were observed in the PB compartment. The percentage of CD4+, CD25high, Foxp3+ cells in BALF increased in horses with active disease compared to horses in remission; this cell population also does not show changes in the PB compartment when RAO positive and RAO negative horses were compared. On the other hand, when the percentage of CD4, Foxp3 positive cells were compared with the percentage of CD4+, CD25high cells, the numbers were very similar. This observation was true for PB and BALF cells from non exposed horses as well as horses exposed to antigen. In all the experimental situations studied, the population expressing all of the markers CD4+, CD25high, Foxp3+ represent only a minor percentage of CD4+, CD25high or CD4+, Foxp3 subpopulations; therefore, an significant number of CD4+, CD25high, Foxp3- and CD4+, CD25null, Foxp3+ cells must exist. Finally, we conclude that horses with RAO show an airway accumulation of T cells bearing regulatory markers that probably are modulating the course of this disease, and that these T cells may be involved in the resolution of immune-mediated bronchial inflammation.
    Veterinary Immunology and Immunopathology 01/2014; DOI:10.1016/j.vetimm.2013.12.005 · 1.54 Impact Factor
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    • "It might be possible that horses in the earliest stage of RAO exhibit an increased production of the cytokines IL-4 and IL-13. After prolonged exposure to allergens, this response enters in a chronic phase characterized by an increased production of IL-8 and IFN␥ (Horohov et al., 2005). Furthermore, it was reported that TGF␤1 is also involved in the advanced stage of the RAO. "
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    ABSTRACT: The goal of the present study was to investigate mRNA expression levels of several cytokines and inflammatory mediators in broncho-alveolar lavage (BAL) fluid and respiratory epithelium in recurrent airway obstruction (RAO)-affected horses. RAO, also called heaves, is a common, performance-limiting, equine respiratory disease with clinical signs and pathophysiological similarities to human asthma, and characterized by bronchospasm, neutrophilic infiltration and increased mucus in the airways. Six RAO-affected horses were examined twice within 15 days and seven clinically healthy horses were examined for comparison. Quantitative real-time RT-PCR was used to assess mRNA expression of the inflammatory mediators IL-1β, IL-6, IL-8, IL-13, IL-17, TNFα, INFγ, TGFβ1, NFκ-β and TRL4 in bronchial biopsies and in BAL fluid. Gene expression levels were then compared with clinical signs, endoscopic examination, complete blood cell count, cytology of BAL fluid, histological examination of bronchial tissue and bacteriological and mycological examinations. Expression of IL1β, IL8, TLR4, TNFα, TGFβ1 and NFkβ transcripts was significantly up-regulated in RAO-affected compared to healthy horses. A similar trend, albeit not significant, was showed for IL17 and INFγ. A highly significant correlation was observed among IL-1β, IL8, TGFβ1, NFkβ, TRL4, and INFγ expression patterns as well as between expression levels of these genes and clinical parameters. In the present study, the comparison between clinically healthy and RAO-affected horses gave new insights on the cytokine expression in equine health and disease status. The identification of cytokines implicated in the pathogenesis of RAO may contribute to the diagnosis and treatment of this disease.
    Veterinary Immunology and Immunopathology 10/2013; 156(3-4). DOI:10.1016/j.vetimm.2013.09.020 · 1.54 Impact Factor
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