Topic:Bronchoalveolar Lavage
Bronchoalveolar lavage (BAL) is a diagnostic procedure used to collect samples from the lower respiratory tract of horses. The technique involves the introduction of a sterile fluid into the bronchi and alveoli, which is then retrieved for analysis. BAL is utilized to assess the cellular and microbiological composition of the lower airways, aiding in the diagnosis of respiratory conditions such as inflammatory airway disease, recurrent airway obstruction, and infections. The procedure provides valuable insights into the type and extent of inflammation or infection present in the respiratory system. This page compiles peer-reviewed research studies and scholarly articles that explore the methodology, applications, and clinical relevance of bronchoalveolar lavage in equine respiratory health.
Investigation of blood biomarkers for the diagnosis of mild to moderate asthma in horses. Asthma in horses is associated with nonspecific respiratory clinical signs and may be manifested only as exercise intolerance. Its diagnosis relies on bronchoalveolar lavage fluid (BALF) cytology in the presence of compatible clinical signs. The identification of blood biomarkers for this condition would facilitate diagnosis in the field, because there are regional areas where BAL is not routinely performed in clinical practice. Objective: Identification of blood biomarkers for the diagnosis of asthma in horses. Methods: Fourteen horses with asthma with increased neutrophil numbers in BALF (ne...
Modeling the pasture-associated severe equine asthma bronchoalveolar lavage fluid proteome identifies molecular events mediating neutrophilic airway inflammation. Pasture-associated severe equine asthma is a warm season, environmentally-induced respiratory disease characterized by reversible airway obstruction, persistent and non-specific airway hyper-responsiveness, and chronic neutrophilic airway inflammation. During seasonal exacerbation, signs vary from mild to life-threatening episodes of wheezing, coughing, and chronic debilitating labored breathing. In human asthma, neutrophilic airway inflammation is associated with more severe and steroid-refractory asthma phenotypes, highlighting a need to decipher the mechanistic basis of this disease chara...
Bronchoalveolar Lavage Cytology Characteristics and Seasonal Changes in a Herd of Pastured Teaching Horses. Equine asthma syndrome (EAS) is a common problem that affects horses of any age. Severe EAS is reported to affect 10-20% of adult horses in the northern hemisphere, while mild/moderate EAS is reported to affect 60-100% of adult horses, depending on the population and geographic region. For both severe and mild/moderate EAS, the presence of lower airway inflammation is attributed to airborne "triggers" such as dust, mold, and bacterial components that horses encounter in hay and stable-environments; and treatment recommendations for horses with EAS often include full-time pasture turnout. The c...
Equine airway inflammation in loose-housing management compared with pasture and conventional stabling. Icelandic horses are often stabled in loose-housing systems, and to date this type of stabling has not been evaluated with regard to its potential impact on respiratory health. The objective was to assess if differences in management systems (eg, conventional stable, loose housing and pasture only) affect the degree of airway inflammation, evaluated by cytology of tracheal aspirate (TA) and bronchoalveolar lavage (BAL) fluid. In total, 84 Icelandic horses (aged 8.1±4.6 years) housed under three different management systems (conventional stables [n=29], loose-house systems [n=29] and pasture [...
The effect of single pretreatment with salbutamol on recovery of bronchoalveolar lavage fluid in horses with suspected or confirmed severe equine asthma. Bronchoalveolar lavage (BAL) is a method for the recovery of respiratory secretion from the lower airways. Objective: To investigate if the administration of a single dose of a bronchodilatator in horses with a suspected or confirmed severe equine asthma could improve recovery of bronchoalveolar lavage fluid (BALF). Methods: Twenty-eight horses with severe equine asthma. Methods: Horses were divided into 2 groups: group "treated" was given salbutamol before endoscopic examination and BALF collection, whereas group "not treated" was not given. BAL was performed with BAL-catheter by instilling 3...
Fungi in respiratory samples of horses with inflammatory airway disease. Fungi contribute to the inflammatory response of lungs in horses with recurrent airway obstruction and in some forms of asthma in humans. The role of fungi in inflammatory airway disease (IAD) has not been assessed. Objective: Evaluate the prevalence of fungi in the respiratory samples of horses diagnosed with IAD, describe clinical signs associated with the presence of fungi in respiratory samples, and assess the risk factors associated with IAD and with the presence of fungi in the airways. Methods: Seven-hundred thirty-one active horses referred to a specialized ambulatory practice for sign...
Contribution of lung function tests to the staging of severe equine asthma syndrome in the field. Staging methods are useful tools for monitoring disease and response to treatment, and because Severe Equine Asthma Syndrome (SEAS) has a high prevalence in the equine population, a clinical staging method can provide important information to optimize equine care. Our team has previously developed and published a clinical staging method for SEAS and in the present study we further evaluated information provided by lung function tests, in order to determine their contribution to disease staging. Using discriminant analysis we set out to produce a new staging method with applicability in the fie...
Bronchoalveolar lavage fluid from both lungs in horses: Diagnostic reliability of cytology from pooled samples. Cytology of bronchoalveolar lavage fluid (BALF) from one lung may not predict findings in the contralateral lung of the same horse. The aim of this study was to determine whether a pooled BALF from both lungs was representative of corresponding individual samples. Fifty-one horses referred for poor performance and/or respiratory signs and for which a BALF was collected from both lungs, were included in the study. Cytology of pooled and individual BALF samples were performed using a masked protocol. Based on clinical signs and individual BALF cytologies, horses were classified as control (CTL),...
The influence of hay steaming on clinical signs and airway immune response in severe asthmatic horses. Avoidance of antigenic stimuli was found to significantly reverse airway obstruction of horses with severe equine asthma (sEA). To date, no published study investigated the influence of steaming hay on lower airway condition of sEA-affected horses. The objectives were to determine the clinical, cytological and cytokine respiratory responses of both sEA and control (CTL) horses experimentally exposed to steamed or dry hay. Results: A cohort of 6 sEA horses and 6 CTL horses was involved in this field study. On day 0, both groups were fed with steamed hay for 5 consecutive days, followed by a was...
Metabolomics of tracheal wash samples and exhaled breath condensates in healthy horses and horses affected by equine asthma. The present work characterized the metabolomic profile of tracheal wash (TW) and exhaled breath condensate (EBC) in healthy horses and horses with respiratory disease. Six asthma-affected horses (group A) and six healthy controls (group H) underwent clinical, endoscopic and cytologic examinations of upper airways to confirm the active phase of asthma. TW and EBC samples were collected from each animal and investigated by proton nuclear magnetic resonance (H-NMR) metabolomic analysis. A total of ten out of 38 metabolites found in the TW were significantly different between the groups (p < ...
An observational study of environmental exposures, airway cytology, and performance in racing thoroughbreds. Mild equine asthma is presumed to arise in response to environmental exposures but the relative impact of differing inflammatory phenotypes upon performance are largely unexplored. Objective: Airway inflammation negatively affects performance and cytological phenotype varies with environmental exposure. Methods: Thoroughbred racehorses in active training and racing. Methods: Thoroughbreds were recruited 24-48 hours before racing. Each horse was eligible for re-enrollment with each race entry. Within one hour of race completion, physical examination, respiratory endoscopy, and BAL were performe...
Bronchoalveolar lavage fluid cytology and airway hyper-reactivity in clinically normal horses. To characterise the relationship between bronchoalveolar lavage fluid (BALF) cytology and pulmonary function testing with histamine bronchoprovocation (HBP) methods in a population of clinically normal horses. Methods: Cross-sectional study METHODS: Clinically normal adult horses (n = 33) underwent pulmonary function testing and HBP with a commercial flowmetric plethysmography system. BAL was performed 1-5 days later. Statistical analysis was used to assess associations between BALF cell concentration, relative inflammatory cell percentages and categorisation, and airway hyper-reactivity...
Efficacy of tamoxifen for the treatment of severe equine asthma. Tamoxifen, a selective estrogen receptor modulator, decreased airway neutrophilia and improved clinical signs in an experimental model of equine asthma, and induced neutrophilic apoptosis in vitro. Objective: Tamoxifen reduces airway neutrophilia and improves lung function in severe asthmatic horses. Methods: Twelve severe asthmatic horses from a research herd. Methods: Randomized controlled blinded study design. The effects of a 12-day oral treatment with tamoxifen (0.22 mg/kg, q24h) or dexamethasone (0.06 mg/kg, q24h) on lung function, endoscopic tracheal mucus score and bronchoalveolar ...
Does antimicrobial therapy improve outcomes in horses with severe equine asthma and a positive tracheal wash bacterial culture? The objective of this study was to observe the outcomes of adding an antimicrobial treatment to a conventional treatment regime in horses with severe equine asthma in a clinical setting. Eleven client-owned horses with a history consistent with severe equine asthma, increased respiratory effort and nostril flaring, ≥ 20% neutrophils on bronchoalveolar lavage (BAL), and a positive tracheal wash (TW) bacterial culture were treated with environmental management, corticosteroids, and bronchodilators. Six horses were also treated with an antimicrobial (principal group), while the other 5 were adm...
Exhaled breath condensate hydrogen peroxide, pH and leukotriene B4 are associated with lower airway inflammation and airway cytology in the horse. Exhaled breath condensate (EBC) analysis is a noninvasive method to assess the lower respiratory tract. In human subjects, EBC hydrogen peroxide (H O ), pH and leukotriene B (LTB ) are useful for detection and monitoring of inflammatory lung diseases, including asthma. Objective: To determine associations between EBC biomarkers and cytological and endoscopic definitions of lower airway inflammation (LAI) while controlling for sampling and environmental variables. Methods: Prospective, cross-sectional study. Methods: Clinical, endoscopic and airway cytological findings from 47 horses were compa...
Evaluation of Histogel- and Gelfoam-embedded bronchoalveolar lavage and transtracheal wash fluids compared with cytocentrifuged and sediment smear preparations. Storage and temperature significantly impact bronchoalveolar lavage fluid (BALF) analysis, and shipment of samples to diagnostic laboratories is often necessary. Alternative sample preparation methods could limit storage and temperature effects. Objective: This study aimed to determine if airway wash samples that were fixed in formalin after being embedded in Histogel or Gelfoam gave comparable results to fresh cytocentrifuged or sediment smear preparations for the evaluation of cell morphology. Methods: Eleven bronchoalveolar lavage and 3 transtracheal wash fluids were available, including 8 ...
Tumor necrosis factor-alpha protein concentrations in bronchoalveolar lavage fluid from healthy horses and horses with severe equine asthma. The objective of this study was to determine if TNF-α protein concentration differs in bronchoalveolar lavage fluid (BALF) obtained from healthy horses, horses with naturally occurring exacerbations of severe equine asthma and horses in remission from severe equine asthma. Tumor necrosis factor-alpha (TNF- α) protein concentrations were determined in BALF by commercial equine ELISA. Horses with naturally occurring exacerbation of severe equine asthma were found to have significantly lower BALF TNF-α protein concentrations than healthy horses (p = 0.0026). There was no significant differ...
Effects of on-slide fixation on the cell quality of cytocentrifuged equine bronchioalveolar lavage fluid. During bronchoalveolar lavage fluid (BALF) sample preparation in horses, several technical aspects can affect sample variability. To date, the effects of different fixatives on prepared equine BALF films have been insufficiently investigated. Objective: This study aimed to determine the effect of various on-slide fixation methods on cell quality, including spray fixation of wet films, and acetone and methanol fixation of air-dried samples in comparison with unfixed, air-dried films. Methods: Cytocentrifuged BALF samples from 5 horses were fixed in a wet state using a commercially available fix...
Glucocorticosteroids administration is associated with increased regulatory T cells in equine asthmatic lungs. Recurrent inflammation in severe equine asthma causes a remodeling of the airways leading to incompletely reversible airway obstruction. Despite the improvement of clinical signs and lung function with glucocorticoids (GC), inflammation, translated by an increased percentage of neutrophils, persists in the airways. Regulatory T cells (Treg) have been shown to have anti-inflammatory properties and play an important role in balancing the immune response by suppressing effector lymphocyte activity. However, interactions between Treg, neutrophils and glucocorticosteroids in vivo are unclear, parti...
Comparison of Tracheal Wash and Bronchoalveolar Lavage Cytology in 154 Horses With and Without Respiratory Signs in a Referral Hospital Over 2009-2015. Most equine lower respiratory diseases present as increased airway neutrophilia, which can be detected in tracheal wash (TW) or bronchoalveolar lavage fluid (BALF) cytology samples. The aim was to compare the TW and BALF results in a population of client-owned horses with and without clinical respiratory disease signs. A secondary aim was to determine the sensitivity (Se) and specificity (Sp) of TW and BALF neutrophilia in detecting respiratory disease. The cutoff values for neutrophils were also evaluated. Retrospective data from 154 horses of various breeds that had been subject to both TW a...
Influence of bronchoalveolar lavage on thoracic radiography in the horse. Bronchoalveolar lavage (BAL) and thoracic radiography are routinely performed diagnostic procedures. We hypothesized that BAL increases the interstitial opacity of caudoventral and caudodorsal thoracic radiographs. Fifty-three horses, including 8 clinic owned and 45 from a referral hospital population, were classified as healthy controls (n = 12), severe equine asthma (recurrent airway obstruction, n = 12) or mild-to-moderate equine asthma (inflammatory airway disease, n = 21) based on the results of a clinical scoring system. Eight were excluded due to different diagnoses and poor image quali...
Effect of a syringe aspiration technique versus a mechanical suction technique and use of N-butylscopolammonium bromide on the quantity and quality of bronchoalveolar lavage fluid samples obtained from horses with the summer pasture endophenotype of equine asthma. OBJECTIVE To evaluate the effect of 2 bronchoalveolar lavage (BAL) sampling techniques and the use of N-butylscopolammonium bromide (NBB) on the quantity and quality of BAL fluid (BALF) samples obtained from horses with the summer pasture endophenotype of equine asthma. ANIMALS 8 horses with the summer pasture endophenotype of equine asthma. PROCEDURES BAL was performed bilaterally (right and left lung sites) with a flexible videoendoscope passed through the left or right nasal passage. During lavage of the first lung site, a BALF sample was collected by means of either gentle syringe aspirati...
Exercise-induced pulmonary hemorrhage in barrel racing horses in the Pacific Northwest region of the United States. Exercise-induced pulmonary hemorrhage (EIPH) refers to bleeding from the lungs in association with strenuous exercise. It has been documented in race horses but little information exists on EIPH in barrel racing horses. Objective: Our goals were to evaluate the presence of EIPH in barrel racing horses and estimate its prevalence in the Pacific Northwest. Methods: 149 barrel racing horses enrolled at events in WA (11), ID (3), and MT (33). Methods: Observational cross-sectional study. Data collected included signalment, history of illness, respiratory disease, race division, and pre-race medica...
Bronchoalveolar lavage fluid neutrophilia is associated with the severity of pulmonary lesions during equine asthma exacerbations. The severe form of equine asthma is associated with pathological changes of the peripheral airways and pulmonary parenchyma that are only partly described. Also, the relationship between these structural alterations and the percentage of neutrophils found within the airway lumen, assessed by bronchoalveolar lavage fluid (BALF) cytology, remains ill-defined. Objective: To examine the histological lesions associated with equine asthma during disease exacerbation and remission, and their relationship with lung function and BALF neutrophilia. Methods: Observational retrospective study. Methods: Pe...
Neutrophil extracellular traps are downregulated by glucocorticosteroids in lungs in an equine model of asthma. Severe neutrophilic asthma is poorly responsive to glucocorticosteroids (GC). Neutrophil extracellular traps (NETs) within the lungs have been associated with the severity of airway obstruction and inflammation in asthma, and were found to be unaffected by GC in vitro. As IL-17 is overexpressed in neutrophilic asthma and contributes to steroid insensitivity in different cell types, we hypothesized that NETs formation in asthmatic airways would be resistant to GC through an IL-17 mediated pathway. Six neutrophilic severe asthmatic horses and six healthy controls were studied while being treated...
Effectiveness of furosemide in attenuating exercise-induced pulmonary haemorrhage in horses when administered at 4- and 24-h prior to high-speed training. Due to the high prevalence of EIPH in racehorses and its potential impact on the horse's health, furosemide administration is permitted up to 4-h prior to post time in most North American racing jurisdictions. Anecdotal reports suggest that administration of furosemide 24-h prior to strenuous exercise may be equally effective in decreasing the severity of EIPH. Objective: To 1) compare the efficacy of furosemide in reducing the presence and severity of EIPH when administered 4- or 24-h prior to strenuous exercise 2) characterise electrolyte and blood parameters following administration of furo...
Pulmonary disposition and pharmacokinetics of minocycline in adult horses. OBJECTIVE To determine pharmacokinetics and pulmonary disposition of minocycline in horses after IV and intragastric administration. ANIMALS 7 healthy adult horses. PROCEDURES For experiment 1 of the study, minocycline was administered IV (2.2 mg/kg) or intragastrically (4 mg/kg) to 6 horses by use of a randomized crossover design. Plasma samples were obtained before and 16 times within 36 hours after minocycline administration. Bronchoalveolar lavage (BAL) was performed 4 times within 24 hours after minocycline administration for collection of pulmonary epithelial lining fluid (PELF) and BAL ...
Expression of extracellular matrix metalloproteinase inducer and matrix metalloproteinase-2 and -9 in horses with chronic airway inflammation. OBJECTIVE To examine whether expression of extracellular matrix metalloproteinase inducer (EMMPRIN) can be detected in equine lungs and whether it correlates with matrix metalloproteinase (MMP)-2 and -9 expression in bronchoalveolar lavage fluid (BALF) of horses with chronic inflammation of the lungs (ie, lower airway inflammation [LAI]). ANIMALS 29 horses with signs of chronic respiratory tract disease, which were classified as the LAI (n = 17) and LAI with respiratory distress (RDLAI [12]) groups, and 15 control horses. PROCEDURES BALF, tracheal aspirate, and blood samples were obtained, and...
Bioavailability and tolerability of nebulised dexamethasone sodium phosphate in adult horses. Nebulisation of the injectable dexamethasone sodium phosphate (DSP) would offer an inexpensive way of delivering a potent corticosteroid directly to the lungs of horses with asthma. However, this approach would be advantageous only if systemic absorption is minimal and if the preservatives present in the formulation do not induce airway inflammation. Objective: To investigate the bioavailability of nebulised DSP and determine whether it induces airway inflammation or hypothalamic-pituitary-adrenal (HPA) axis suppression in healthy adult horses. Methods: Randomised crossover experiment. Methods...
Effect of Dexamethasone and Fluticasone on Airway Hyperresponsiveness in Horses With Inflammatory Airway Disease. Airway hyperresponsiveness (AWHR), expressed as hypersensitivity (PC R ) or hyperreactivity (slope of the histamine dose-response curve), is a feature of inflammatory airway disease (IAD) or mild equine asthma in horses. Glucocorticoids are used empirically to treat IAD. Objective: To determine whether dexamethasone (DEX) (0.05 mg/kg IM q24h) and inhaled fluticasone (FLUT) (3,000 μg q12h) administered by inhalation are effective in decreasing AWHR, lung inflammation, and clinical signs in horses with IAD. Methods: A randomized crossover study design was used. Eight horses with IAD were assign...