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 (original) (raw)
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American Journal of Veterinary Research, 2006
Objective—To evaluate time-dependent alterations in gene expression of chemokines in bronchial epithelium of recurrent airway obstruction (RAO)-affected horses and whether alterations resulted from increases in gene expression of interleukin (IL)-17 in cells isolated from bronchoalveolar lavage fluid (BALF). Animals—8 RAO-susceptible horses and 9 control horses. Procedure—In 2 experiments, both groups of horses were evaluated after being maintained on pasture and after being stabled and fed dusty hay for 1, 14, 35, and 49 days (experiment 1) or 14 and 28 days (experiment 2). In experiment 1, gene expression of IL-8, chemokine (C-X-C motif) ligand 1 (CXCL1), granulocyte-macrophage colony-stimulating factor (GM-CSF), granulocyte colony-stimulating factor (G-CSF), and Toll-like receptor 4 (TLR4) in epithelium and IL-8, IL-17, and TLR4 in BALF cells was measured. In experiment 2, bronchial biopsy specimens were evaluated for IL-8 immunoreactivity. Results—In RAO-susceptible horses after...
Pulmonary Remodeling in Equine Asthma: What Do We Know about Mediators of Inflammation in the Horse?
Mediators of Inflammation
Equine inflammatory airway disease (IAD) and recurrent airway obstruction (RAO) represent a spectrum of chronic inflammatory disease of the airways in horses resembling human asthma in many aspects. Therefore, both are now described as severity grades of equine asthma. Increasing evidence in horses and humans suggests that local pulmonary inflammation is influenced by systemic inflammatory processes and the other way around. Inflammation, coagulation, and fibrinolysis as well as extracellular remodeling show close interactions. Cytology of bronchoalveolar lavage fluid and tracheal wash is commonly used to evaluate the severity of local inflammation in the lung. Other mediators of inflammation, like interleukins involved in the chemotaxis of neutrophils, have been studied. Chronic obstructive pneumopathies lead to remodeling of bronchial walls and lung parenchyma, ultimately causing fibrosis. Matrix metalloproteinases (MMPs) are discussed as the most important proteolytic enzymes dur...
The Immune Mechanisms of Severe Equine Asthma—Current Understanding and What Is Missing
Animals, 2022
Severe equine asthma is a chronic respiratory disease of adult horses, occurring when genetically susceptible individuals are exposed to environmental aeroallergens. This results in airway inflammation, mucus accumulation and bronchial constriction. Although several studies aimed at evaluating the genetic and immune pathways associated with the disease, the results reported are inconsistent. Furthermore, the complexity and heterogeneity of this disease bears great similarity to what is described for human asthma. Currently available studies identified two chromosome regions (ECA13 and ECA15) and several genes associated with the disease. The inflammatory response appears to be mediated by T helper cells (Th1, Th2, Th17) and neutrophilic inflammation significantly contributes to the persistence of airway inflammatory status. This review evaluates the reported findings pertaining to the genetical and immunological background of severe equine asthma and reflects on their implications i...
Diagnostic value of inflammatory markers in chronic respiratory disease of the horse – a review
Pferdeheilkunde Equine Medicine, 2014
Over the last years local and systemic inflammatory markers of chronic pneumopathies have gained increasing interest in research, as the pathogenesis of Recurrent airway obstruction (RAO) and Inflammatory airway disease (IAD) remains not fully elucidated in several details. In human medicine, Asthma bronchiale and Chronic obstructive pulmonary disease (COPD) have been found to be influenced by systemic inflammatory processes and the other way around. Inflammation, coagulation and fibrinolysis as well as extracellular remodeling show close interactions. Cytology of bronchoalveolar lavage fluid and tracheal wash is commonly used to evaluate the severity of local inflammation in the lung. Interleukins involved in the chemotaxis of neutrophils like Interleukin 8, 17 and 23 have been studied. Chronic obstructive pneumopathies lead to remodeling of bronchial walls and lung parenchyma, ultimately causing fibrosis. Matrix-metalloproteinases (MMPs) are discussed as the most important proteolytic enzymes during remodeling in human medicine. In the horse, MMP 9 seems to be a central player in chronic respiratory disease as well. A systemic involvement has been shown for RAO by increased acute-phaseproteins like serumamyloid A and haptoglobin in peripheral blood during exacerbation. Studies focusing on these and further possible inflammatory markers for chronic respiratory disease in the horse are discussed in this review of literature.
BMC Veterinary Research, 2008
Background: The aim of this study was to evaluate the contribution of bronchial epithelium to airway inflammation, with focus on mRNA and protein expression of cytokines of innate immunity IL-6, IL-10 and TNF-α, in horses with Recurrent Airway Obstruction (RAO) during exacerbation and in remission. Results: Despite marked clinical and physiologic alterations between exacerbation and after remission in the RAO horses no differences were detected in either cytokine mRNA or protein levels. Moreover, the expression of investigated cytokines in RAO horses on pasture did not differ from controls. In comparing real-time PCR analysis to results of immunohistochemistry only IL-10 mRNA and protein levels in RAO horses on pasture were significantly correlated (r s = 0.893, p = 0.007). Curiously, in controls examined on pasture the TNF-α protein level was positively correlated to IL-10 mRNA expression (r s = 0.967, p = 0.007) and negatively correlated to IL-6 mRNA expression (r s =-0.971, p = 0.001). Conclusion: Given the complementary relationship of assessing cytokines directly by immunohistochemistry, or indirectly by PCR to mRNA, the lack of significant changes in either mRNA or protein levels of IL-6, IL-10 or TNF-α mRNA in RAO horses in exacerbation suggests that these particular cytokines in bronchial tissue may not play a substantive role in the active inflammation of this disease. To support this contention further studies examining time dependency of expression of IL-6, IL-10 or TNF-α are needed, as is expansion of the range of cytokines to include other key regulators of airway inflammation.
American Journal of …, 2007
obstruction, and stabling of susceptible horses triggers acute disease exacerbations. Stable dust is rich in endotoxin, which is recognized by Toll-like receptor (TLR) 4. In human bronchial epithelium, TLR4 stimulation leads to elevation of interleukin (IL)-8 mRNA expression. The zinc finger protein A20 negatively regulates this pathway. We hypothesized that TLR4 and IL-8 mRNA, and neutrophil numbers are elevated, and that A20 mRNA is not increased in RAOs during stabling compared to controls, and to RAOs on pasture. We measured the maximal change in pleural pressure (4Ppl max ), determined inflammatory cell counts in bronchoalveolar lavage fluid (BAL), and quantified TLR4, IL-8 and A20 mRNA in bronchial epithelium by qRT-PCR. We studied six horse pairs, each pair consisting of one RAO and one control horse. Each pair was studied when the RAO-affected horse had airway obstruction induced by stabling, and after 7, 14 and 28 days on pasture. Stabling increased BAL neutophils, 4Ppl max and TLR4 (4.14-fold change) significantly in RAOs compared to controls and to RAOs on pasture. TLR4 correlated with IL-8 (R 2 = 0.75). Whereas stabling increased IL-8 in all horses, 2 A20 was unaffected. IL-8 was positively correlated with BAL neutrophils (R 2 = 0.43) and negatively with A20 (R 2 = 0.44) only in RAO-affected horses. Elevated TLR4 expression and lack of A20 upregulation in bronchial epithelial cells from RAO-affected horses may contribute to elevated IL-8 production, leading to exaggerated neutrophilic airway inflammation in response to inhalation of stable dust.
Veterinary immunology …, 2008
The aim of this study was to investigate mRNA levels of cytokines in bronchial epithelium in horses with recurrent airway obstruction (RAO) during acute crisis and remission. Additionally, cytokine mRNA levels in endobronchial biopsies and bronchoalveolar lavage (BAL) cells were compared. Seven RAO horses were examined while in respiratory crisis following provocation and again while in remission after 2 months on pasture, during which time six healthy horses on pasture were also examined. Quantitative real-time PCR (RT-PCR) was used to assess mRNA expression for cytokines IL-5, IL-6, IL-8, IL-10, IL-17 and transforming growth factor b1 (TGF-b1) in endobronchial biopsies and bronchoalveolar lavage. Expression of IL-8 mRNA was significantly upregulated during crisis in both endobronchial biopsies and BAL cells (p = 0.036), while there was a similar trend for upregulation of IL-10 mRNA only in BAL cells that approached significance (p = 0.059). Moreover, during crisis the expression of IL-8 mRNA in BAL cells was positively correlated to relative IL-6 mRNA expression (r s = 0.971, p = 0.001) and bronchial epithelial expression of IL-10 and TGF-b1 mRNA were positively correlated (r s = 0.943, p = 0.005). In comparing the relationship of mRNA expression in BAL to biopsy in individual RAO horses, there was a positive correlation with IL-6 to IL-8 mRNA expression in BAL during respiratory crisis (r s = 0.971, p = 0.001) that also correlated positively with IL-8 expression in biopsies on pasture (r s = 0.986, p < 0.0001 for both). Regarding RAO horses at pasture versus controls neither the cytokine mRNA levels in endobronchial biopsy nor in BAL cells differed significantly. These results further support previous findings that IL-8 mRNA in both BAL cells and bronchial epithelium is upregulated in RAO horses during crisis. However, apart from IL-8, it appears that expression of other cytokines, including IL-5, IL-6, IL-10, IL-17 and TGF-b1 in bronchial epithelium does not necessarily mirror cytokine expression in BAL cells in individual horses with RAO. Accordingly, examination of markers of inflammation in endobronchial tissue provides complementary but not necessarily identical information to that obtained in BAL cells. Given the potential for repeated sampling over time bronchial biopsy www.elsevier.com/locate/vetimm
Veterinary Immunology and Immunopathology, 2003
In horses prone to developing recurrent airway obstruction (RAO), we tested the hypotheses that the cytokine profile in the bronchoalveolar lavage (BAL) cells of affected horses would reflect a polarized Th-2 response; that cytokine and chemokine alterations would occur within 24 h of allergen exposure; and that allergen exposure would induce alterations in the expression of the transcription factor t-bet (t-box-expressed in T-cells). The expression levels of interleukin-4 (IL-4), IL-13, Interferongamma (IFN-g), t-bet, IL-8 and granulocyte-macrophage colony stimulating factor (GM-CSF) were measured in BAL cells obtained from control and RAO-susceptible horses during an asymptomatic phase and at 24 h and 5 weeks post-stabling and hay exposure. At each sampling time, BAL neutrophil percentages in the RAO-group exceeded controls. In the RAO-group, only IL-13 expression was decreased 2-fold during the asymptomatic phase. No differences in cytokine or chemokine expression were detected during the acute exposure phase. During the chronic phase, IFN-g and IL-8 expression levels were 2.5-and 3-fold greater, respectively, in the RAO-group. No other differences in gene expression were detected. We conclude that the cytokine profile of the airway cells does not reflect a polarized Th-2 response; that increases in IFN-g result from a t-bet independent pathway and that chemokines from epithelial or interstitial cells may contribute to early neutrophil influx.
American Journal of Respiratory and Critical Care Medicine, 2001
Heaves in horses shares many similarities with human asthma, including lower airway inflammation, reversible airway obstruction, and bronchial hyperresponsiveness. Extrinsic asthma is an allergic response to environmental allergens and a similar immunologic mechanism may be implicated in heaves. It is now recognized that a Th2 subset of CD4 ϩ lymphocytes is associated with allergic diseases such as atopic asthma. The purpose of this study was to determine whether airway inflammation in heaves is associated with a pattern of expression of cytokine suggestive of a Th2 type response. The expression of mRNA, encoding interleukin (IL)-4, IL-5, and interferon gamma (IFN-␥) was measured in bronchoalveolar cells from seven horses with heaves and five control horses, using in situ hybridization and radiolabeled equine-specific cRNA probes coding for these cytokines. Bronchoalveolar cells of horses with heaves had an increased expression of IL-4 (p ϭ 0.01) and IL-5 (p ϭ 0.02) mRNA and a decreased expression of INF-␥ (p ϭ 0.01) compared with control horses. Here we show that inflammatory cells in lungs from horses with heaves display a Th2-type cytokine profile that is consistent with the hypothesis that heaves is an allergic condition with similarity to human asthma.