Topic:Asthma
Equine asthma, also known as equine recurrent airway obstruction (RAO) or heaves, is a chronic respiratory condition affecting horses. It is characterized by airway inflammation, mucus production, and bronchoconstriction, leading to clinical signs such as coughing, nasal discharge, and labored breathing. The condition is often exacerbated by environmental factors such as dust, mold, and pollen, which can trigger an immune response in susceptible horses. Equine asthma is managed through environmental modifications, medical treatments, and sometimes dietary adjustments to alleviate symptoms and improve respiratory function. This page compiles peer-reviewed research studies and scholarly articles that explore the pathophysiology, diagnosis, and management strategies of equine asthma.
Tracheal wash culture is not associated with bronchial infection, remodelling or inflammation in horses with asthma. Antimicrobials are commonly prescribed for the treatment of equine asthma, despite limited evidence supporting their use. Tracheal wash (TW) bacterial culture results are known to influence antimicrobial prescription decisions. Objective: To determine whether a positive TW bacterial culture in horses with asthma is associated with bronchial infection or colonisation, increased bronchial remodelling and airway inflammation by evaluating the presence of bacteria and airway remodelling in endobronchial biopsies, as well as bronchoalveolar lavage fluid (BALF) cytology and tracheal mucus scores. Me...
A randomized, masked, crossover, clinical trial of the efficacy and safety of nebulized albuterol sulfate and dexamethasone sodium phosphate in asthmatic horses. Nebulization of injectable dexamethasone sodium phosphate (DSP; 0.01 mg/kg) to horses with severe equine asthma (SEA) was previously found to be ineffective. Horses with SEA have marked bronchoconstriction that decreases peripheral lung deposition of nebulized drugs. Administration of a bronchodilator immediately before nebulizing dexamethasone may improve efficacy. Objective: Evaluate the therapeutic effects and optimal dose of nebulized DSP after nebulized albuterol in horses with SEA. Methods: Seven horses with SEA from a research herd. Methods: In this masked randomized crossover trial, h...
Analysis of lipid mediator profiles in the blood of horses with equine asthma using UPLC-MS/MS. Equine asthma (EA) is a chronic inflammatory disease of the lower respiratory tract in horses, which is mainly triggered by dusty hay. EA is becoming increasingly acknowledged as a valuable animal model for studying human asthma. Research on the pathogenesis of EA has primarily focused on the associated cells and cytokines involved. However, the role of inflammation-related lipid mediators (LM) in the development and progression of equine asthma remains elusive. LMs are categorized into pro-inflammatory arachidonic acid (AA)-derived leukotrienes (LTs) and prostaglandins (PGs), as well as infla...
An in-hospital clinical trial assessing nebulized lidocaine compared to saline for treatment of asthma in horses. Corticosteroids are the main pharmacologic treatment for equine asthma (EA) but may have adverse effects in metabolically unstable horses. Recent pilot studies support the use of nebulized lidocaine as an alternative treatment option. Objective: Nebulized lidocaine will improve EA-associated clinical variables and airway inflammation. Methods: Twenty client-owned horses diagnosed with EA. Methods: Randomized, blinded, in-hospital study comparing 1 mg/kg preservative-free 4% lidocaine (n = 10) nebulized via Flexineb (twice daily for 7 doses) to 0.9% saline control (n = 10). Clinical examin...
Multi-Kingdom Fecal Microbiota Alterations in Horses with Severe Equine Asthma. Severe equine asthma (SEA) is a chronic inflammation of airways affecting ~14-20% of adult horses in the Northern Hemisphere. SEA is characterized by a mixed phenotype of T helper cell responses with marked neutrophilia in the bronchoalveolar lavage fluid (BALF) of affected horses. Human studies have demonstrated the impact of gut microbiota in many diseases, including asthma susceptibility and severity. However, the potential role of the gut-lung axis in the development and persistence of SEA remains to be determined. This study aimed to identify key bacterial, archaeal, and fungal microbiota...
Proteomic profiling of equine airway mucus reveals compositional changes in asthmatic phenotypes. Mucus hypersecretion and accumulation are hallmark features of equine asthma (EA), a meaningful respiratory disorder in horses occurring in mild to moderate (MEA) and severe (SEA) forms. Changes of the proteomic composition of airway mucus in EA are poorly understood. Using label-free quantitative liquid chromatography-mass spectrometry, we analyzed airway mucus from SEA (n = 10), MEA (n = 6), and healthy (n = 8) horses. We identified and quantified 2,275 proteins including gel-forming mucins MUC5AC and MUC5B and membrane-bound mucins MUC1 and MUC4. Compared with healthy controls, ...
Genomic Epidemiology of Fungi Identified in Bronchoalveolar Lavage Fluid from Asthmatic Horses in the US. Fungal exposure is strongly implicated in the pathogenesis of asthma in horses, but the importance of specific fungi is unknown. Geographic variation in equine asthmatic endotypes is suspected and might be related to different fungal exposures due to different climatological and geographical conditions. This study had two objectives: evaluate the effect of the ecoregion upon BALF inflammatory cells and fungal community composition in horses with asthma and evaluate the effect of BALF fungal community composition upon the likelihood of neutrophilic, mastocytic and eosinophilic inflammation in t...
RNA-seq evaluation of equine alveolar macrophages and monocyte-derived macrophages exposed to an inflammatory stimulus (short communication). Macrophage populations in the lung, including resident alveolar macrophages (AMs) and recruited monocyte-derived macrophages (MDMs), recognize the inhaled particulates in barn dust that cause severe equine asthma and orchestrate an immune response though the cytokines they produce. Despite their importance, the specific contributions of these macrophage subsets to lower airway inflammation remain poorly understood. This exploratory in vitro study investigated the likely contributions of AMs and MDMs from healthy horses to the early inflammatory response using RNA-seq. If biologically importan...
A Portable Fluorometer Detects Significantly Elevated Cell-Free DNA in Tracheal Wash and Bronchoalveolar Lavage Fluid in Horses with Severe Asthma. Severe equine asthma (sEA) is characterized by increased lower airway neutrophils that contribute to dysregulated inflammation through the release of cytokines, reactive oxygen species and neutrophil extracellular traps (NETs). NETs are composed of cell-free DNA (cfDNA) intercalated with enzymatic proteins and are known to be increased in the lower airway of asthmatic horses. The objectives of this study were two-fold: 1. Determine if cfDNA can be accurately measured in equine bronchoalveolar lavage fluid (BALF) and tracheal wash (TW) with a Qubit 4 fluorometer. 2. Determine whether Qubit-meas...
Field-applicable low-intensity exercise induces bronchodilation in horses with severe asthma. Airway dysfunction in severe equine asthma (SEA) often results in early retirement or euthanasia of affected horses. Exercise-induced bronchodilation occurs in horses with SEA after intense treadmill exercise, but the effects of a lighter, field-applicable, training regimen remain largely unexplored. Objective: To evaluate the impact of submaximal aerobic exercise on airway obstruction during exacerbation of SEA. Methods: The preliminary phase explored the effects of a 25-min standardised exercise on the lung function of eight SEA horses. As notable bronchodilation occurred, the results were c...
Equine Asthma Is Characterised by Severity-Dependent Correlations Between Blood Neutrophil Cholesterol Content and NET Formation. Equine asthma (EA) is the most prevalent chronic lung disease in horses. Neutrophils are the main effector cells in severe EA. Neutrophil extracellular traps (NETs) have been described as contributors to severity in human asthma and chronic obstructive pulmonary disease. Thus, we aimed to investigate if NET-related factors in equine neutrophils, blood and bronchoalveolar lavage fluid (BALF) allow us to differentiate EA severities and to identify NET-related mechanistic insights in EA. We quantified NETs and NET-related factors in the blood and BALF of eight healthy horses and 18 horses with di...
Steamed hay for the prevention of severe equine asthma exacerbations. Steaming hay reduces respirable particles and is commonly used to feed horses with asthma. However, it showed inconsistent benefits in clinical studies. Objective: (1) To assess the effects of steamed hay on lung function and airway inflammation in horses with severe equine asthma (SEA) in remission; (2) To compare these effects with a dry hay diet. Methods: Cross-over in vivo experiment. Methods: Horses were fed steamed and dry hay for 4 weeks in a prospective, cross-over study, with a 4-week washout period. Lung function, bronchoalveolar lavage (BALF) cytology, and a 23-point weighted clin...
Effects of mixed polyphenol supplementation on lower airway inflammation in horses with Equine Asthma Syndrome. Equine Asthma Syndrome (EAS) is a chronic inflammatory respiratory disease of adult horses. While dietary polyphenols have shown anti-inflammatory effects in human asthma, their use in equine asthma has not been studied. Objective: To evaluate the effects of a mixed polyphenol supplement on systemic and pulmonary inflammation, bronchoalveolar lavage (BAL) cytology, and clinical respiratory signs in healthy and asthmatic horses. We hypothesized that polyphenol supplementation would decrease systemic and pulmonary inflammation in both healthy and asthmatic horses and would improve BAL cytology a...
Influence of a Standardized Lunging Exercise Test on BALF Cytology in Horses Suffering from Mild-Moderate Equine Asthma. Mild-moderate equine asthma (MEA) is a very common but underdiagnosed pulmonary disease in horses, with mild cases not showing clinical respiratory signs. This study evaluates the influence of a standardized lunging exercise test (SLET) on bronchoalveolar lavage fluid (BALF) cytology in MEA horses. We hypothesized that SLET would increase the total nucleated cell count (TNCC) and/or percentages of inflammatory cells associated with EA. In a prospective, randomized, non-blinded, between-subjects study design of two independent groups, 39 horses (17 mild and 22 moderate) were included. They were...
Equine Asthma in a Comparative Perspective: Cardiovascular and Neurological Manifestations of Asthma Across Different Species. Asthma is a multifactorial respiratory disease that naturally occurs in horses, humans, and cats, presenting common clinical signs and species-specific mechanisms. This review addresses the impact of asthma on the cardiovascular and neurological systems, with a primary focus on horses. It highlights the need for new biomarkers beyond the respiratory system due to diagnostic difficulties in animals. A comprehensive literature search was conducted using PubMed and Google Scholar, focusing on cardiovascular and neurological manifestations of asthma in humans, horses, cats, and experimental animal...
Surgical Assessment and Post-Operative Complications Following Video-Assisted Thoracoscopic Surgery (VATS) of Horses with Severe Equine Pasture Asthma During Asthma Exacerbation and Remission. The aim of this retrospective clinical study was to assess surgical duration and surgical and post-operative complications associated with Video-Assisted Thoracoscopic Surgery (VATS) and lung biopsy in horses with severe Equine Pasture Asthma (EPA) and paired control horses. Twelve horses (6 EPA-affected, 6 control) were sex, age and breed matched. Twenty-four thoracic surgeries were performed. Surgery of each matched pair (EPA-affected and healthy) was performed during asthma exacerbation (summer) and remission (winter). Surgical times were shorter with uncomplicated thoracoscopy (85 min) and...
Endoscopically assessed mucus parameters in equine asthma: Relationship to clinical history and cytological findings data. Mucus parameters are hallmark diagnostic features of equine asthma (EA). Objective: To investigate the relationship between mucus quantity score and mucus viscosity score with signalment, history, clinical findings and cytological parameters. Methods: Retrospective cross-sectional study. Methods: Mucus quantity and viscosity scores, signalment, history and clinical findings recorded for diagnostic purposes from up to 1599 samples, and cytological values of the corresponding bronchoalveolar lavage fluid (BALF) and tracheobronchial secretions were analysed. The cut-off value of a mucus quantity ...
Horse owners seeking online health information: a mixed-methods study. Many people seek health-related information online, not only for themselves but also on behalf of others who cannot articulate their symptoms. This proxy information-seeking behavior is particularly relevant for animal owners, who must interpret their animals' symptoms without direct verbal feedback. While online health information-seeking in the context of one's own health is well-studied, the specific challenges of searching by proxy, especially for animal health information, remain largely unexplored. Unassigned: This study aimed to determine the specific information needs and search behavi...
Artificial intelligence in smartphone video analysis for equine asthma diagnostic support. Equine asthma is a prevalent respiratory disease that negatively impacts horses' health and athletic performance. Traditional diagnostic methods are invasive and require specialised equipment. There is a need for a non-invasive, cost-effective screening tool that can be used by veterinarians and horse handlers in ambulatory settings. Objective: To assess the willingness of veterinarians and horse handlers to adopt such a tool (Questionnaire 1) and the challenges associated with visually recognising equine asthma (Questionnaire 2) and to develop EquiBreathe, an artificial intelligence (AI)-powe...
Obesity-Associated Metabolomic and Functional Reprogramming in Neutrophils from Horses with Asthma. Equine asthma is a chronic respiratory disease characterised by neutrophilic inflammation, airway hyperresponsiveness, and impaired pulmonary function. Obesity, increasingly prevalent among domestic horses, has been identified as a potential risk factor for exacerbating inflammatory conditions. This study aimed to explore whether obesity modifies neutrophil metabolism and inflammatory responses in horses affected by asthma. Six asthmatic horses in clinical remission were categorised into two groups: obese and non-obese, based on body condition score. Serum levels of interleukin-1β (IL-1β) an...
The presence of acylated homoserine lactones and diffusible signal factor in bronchoalveolar lavage fluid from horses with clinical exacerbation of severe equine asthma. Several bacteria associated with chronic lung pathology use quorum sensing (QS) signaling molecules to regulate their virulence in pure cultures and poly-microbial communities. Their excessive growth and biofilm formation in the respiratory tract increase the morbidity and mortality of inflammatory airway diseases in humans, such as chronic obstructive pulmonary disease (COPD), asthma and cystic fibrosis (CF). In horses, severe equine asthma (SEA) has many parallels to these human diseases. We hypothesized that QS molecules associated with the most common biofilm-forming lung pathogens in huma...
MARCKS protein is a potential target in a naturally occurring equine model of neutrophilic asthma. Asthma is a chronic inflammatory airway disease that affects millions of people worldwide. Horses develop asthma spontaneously and serve as a relevant model for multiple phenotypes and endotypes of human asthma. In horses with equine asthma (EA), environmental organic dust triggers increased inflammatory cytokines, excess airway mucus, reversible bronchoconstriction, and airway inflammation. In horses with severe EA (sEA), lower airway inflammation is invariably neutrophilic, making sEA a potential model for severe neutrophilic asthma in humans. Alveolar macrophages (AM) and airway neutrophils...
Redox Biomarker Variations With Severity of Asthma in Horses Across Different Sample Types. The contribution of redox imbalance to equine asthma (EA) pathogenesis remains unclear. Objective: (1) validate and measure a panel of redox biomarkers in the tracheal wash (TW) and bronchoalveolar lavage (BAL) samples from horses with neutrophilic and mastocytic mild-moderate EA (MEA) and severe EA. (2) Evaluate the same panel in saliva and serum for comparative purposes. Methods: A total of 117 horses: 37 healthy, 26 mastocytic MEA, 29 neutrophilic MEA, and 25 severe EA. Methods: Cross-sectional study using TW, BAL, and serum and saliva sampling. After assay validation, redox biomarkers-ferr...
Minimising feeding behaviour interference: A hay-shaker device to assess dust exposure in horses. Organic dust from hay is a primary trigger of equine asthma. Objective: (1) To introduce a novel hay-shaker (HS) device for standardised hay dust generation, enabling simultaneous measurements of various particulate matter (PM) size fractions. (2) To compare these measurements with those in the horse's breathing zone (BZ) to assess the influence of environmental and individual factors. Methods: Comparative experimental study. Methods: A HS generating dust was developed. Total dust (PMT) and size fractions (PM1, PM2.5, PM4 and PM10, representing particle size in μm) were measured from 50 hay s...
Respiratory Rate Recovery After Submaximal Lunging Exercise Is Delayed in Asthmatic Horses with Neutrophilic Airway Inflammation. Equine asthma is a common cause of poor performance, but little is known about its impact on submaximal exercise. The aim of the present study was to evaluate the effects of equine asthma and potential confounding factors on recovery of respiratory rate (RR) and heart rate (HR) after a lunging exercise test. Thirty-seven horses completed a standardized 15 min lunging exercise including HR and RR recording pre- and up to 30 min post-exercise and venous blood lactate measurement. Endoscopy was performed and bronchoalveolar lavage fluid cytology was used to categorize horses as controls or asthma...
Use of inhaled ciclesonide for treatment of moderate asthma in Thoroughbred racehorses. Mild-moderate asthma is common in horses. Inhaled ciclesonide has been approved only for treatment of severe asthma in horses. Objective: We hypothesized that a 10-day treatment course of inhaled ciclesonide (Aservo EquiHaler) would improve clinical signs, endoscopic tracheal mucus scores, and bronchoalveolar lavage fluid (BALF) cytology in racehorses with moderate asthma. Methods: Racehorses with moderate asthma housed at the Emerald Downs Racetrack in Auburn, WA. Methods: Prospective, randomized, double-blinded, placebo-controlled clinical study. Horses received inhaled ciclesonide (n = ...
Association between fungal detection, airways inflammation and diagnosis of moderate to severe asthma in horses. Fungi are ubiquitous in horses' environment. Their contribution to the pathophysiology of severe asthma (SA) is acknowledged, while controversies remain for mild-moderate asthma (MA). Objective: We hypothesised that fungi are a risk factor for asthma. Our objective was to compare different combinations of analytical methods (cytology, culture) and sampling sites (tracheal wash (TW), bronchoalveolar lavage fluid (BALF)) in relation to clinical status (control, MA, SA). Methods: Prospective cross-sectional study. Methods: The study population included asymptomatic racing horses in the field and ...
Nebulization of 2% lidocaine has no detectable impact on the healthy equine respiratory microbiota. Glucocorticosteroids remain the most common pharmaceutical approach for the treatment of equine asthma but can be associated with significant side effects, including respiratory microbiome alterations. The goal of the study was to assess the impact of 2% lidocaine nebulization, a projected alternative treatment of equine asthma, on the healthy equine respiratory microbiota. A prospective, randomized, controlled, blinded, 2-way crossover study was performed, to assess the effect of 1 mg/kg 2% lidocaine (7 treatments over 4 days) on the equine respiratory microbiota compared to control horses (s...
Exploring a pico-well based scRNA-seq method (HIVE) for simplified processing of equine bronchoalveolar lavage cells. Single-cell RNA sequencing (scRNA-seq) is a valuable tool for investigating cellular heterogeneity in diseases such as equine asthma (EA). This study evaluates the HIVE™ scRNA-seq method, a pico-well-based technology, for processing bronchoalveolar lavage (BAL) cells from horses with EA. The HIVE method offers practical advantages, including compatibility with both field and clinical settings, as well as a gentle workflow suited for handling sensitive cells. Our results show that the major cell types in equine BAL were successfully identified; however, the proportions of T cells and macropha...
Molecular Assessment of Plasma Concentrations of Selected Adipokines and IL-8 in Horses with Back Pain and Comorbid Asthma-Based on Clinical Cases. Similarly, in humans and horses, thoracic and lumbosacral back pain cause more disability and work interruptions worldwide than any other disease. Given that there are few effective treatments for back pain in humans and animals, primary prevention strategies and a reduction in pain factors may be crucial. In the analysed data obtained for the horses studied, the pattern of changes in adipocytokine concentrations, including resistin, visfatin and leptin, was noted for those with back pain compared to the control animals. Concentrations of selected adipocytokines in horses from the back pain gr...