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.
Pharmacokinetics of oral doxycycline and concentrations in body fluids and bronchoalveolar cells of foals. The objective of this study was to determine the disposition of orally administered doxycycline in foals. Six healthy 4- to 8-week-old foals were used. Doxycycline was administered to each foal via the intragastric (IG) route at dosages of 10 and 20 mg/kg, in a cross-over design. After the first 10 mg/kg dose, five additional doses were administered at 12-h intervals. A microbiological assay was used to measure doxycycline activity in serum, urine, peritoneal fluid, synovial fluid, cerebrospinal (CSF), pulmonary epithelial lining fluid (PELF), and bronchoalveolar (BAL) cells. Following adminis...
Effects of a specific endothelin-1A antagonist on exercise-induced pulmonary haemorrhage (EIPH) in thoroughbred horses. During high intensity exercise, the very high pulmonary artery pressure (Ppa) experienced by Thoroughbred horses is considered a major factor in the aetiology of exercise-induced pulmonary haemorrhage (EIPH). Recently, endothelin-1 (ET-1), a potent vasoconstrictive hormone, has been found to increase Ppa in horses at rest via binding to its ET-1A receptor subtype. In addition, plasma concentrations of ET-1 are increased in horses during and after high intensity exercise. Objective: If ET-1 increases Ppa during exercise in the horse, administration of a specific ET-1A antagonist would decrease ...
Is improved high speed performance following frusemide administration due to diuresis-induced weight loss or reduced severity of exercise-induced pulmonary haemorrhage? Prerace administration of frusemide to horses has been linked with a significant improvement in racing performance, but the basis for this improvement is unclear. Objective: To test whether improved performance with prerace administration of frusemide is due to the drug's diuresis-induced weight loss rather than its apparent alleviation of exercise-induced pulmonary haemorrhage (EIPH). Methods: Eight thoroughbred horses underwent 3 trials in a random order, 2 or 3 weeks apart: control (C), frusemide/unburdened (FU), and frusemide/burdened (FB). None of the horses were known to have exhibited p...
The effect of inspired gas density on pulmonary artery transmural pressure and exercise induced pulmonary haemorrhage. Pulmonary capillary stress failure, largely as a result of high pulmonary vascular pressures, has been implicated in the aetiology of EIPH. However, the role of the respiratory system in determining the magnitude of EIPH has received little attention. Objective: Horses breathing a gas of greater density than air will exhibit greater transmural pulmonary arterial pressures (TPAP) and more severe EIPH, and horses breathing a gas of lower density than air will exhibit lower TPAP and less severe EIPH, both compared with horses breathing air. Methods: Following a warm-up, 8 Thoroughbred horses were...
Prevalence of inflammatory airway disease in national hunt horses referred for investigation of poor athletic performance. Inflammatory airway disease (IAD) is thought to be an important cause of poor performance in young Thoroughbred racehorses. However, little study has been made of IAD in older National Hunt (NH) horses. Objective: To determine the prevalence of IAD in NH racehorses referred for investigation of poor athletic performance and identify some of the risk factors that may be associated with IAD in this group of horses. Methods: Tracheal mucus was graded, and tracheal wash (TW) and bronchoalveolar lavage (BAL) performed after treadmill exercise in 91 NH horses referred to the University of Bristol. C...
Effect of corticosteroid and bronchodilator therapy on bronchoalveolar lavage cytology following intrapulmonary blood inoculation. Intrapulmonary blood causes an inflammatory response. Modifying this inflammatory response may be useful in the treatment of exercise induced pulmonary haemorrhage (EIPH). Objective: To evaluate the efficacy of 3 treatments, an oral bronchodilator, inhaled steroid and oral steroid in modifying the cellular response to intrapulmonary blood inoculation. Methods: Experimental design was a randomised block divided into 4 experimental segments of 2 weeks. Eight normal horses were randomly assigned to pairs and treatments. Autologous blood was inoculated into the lungs on 4 occasions over an 8 week ...
Comparison of prednisolone and dexamethasone effects in the presence of environmental control in heaves-affected horses. This study was designed to compare the efficacy of oral prednisolone and intramuscular (IM) dexamethasone in heaves-affected horses with environmental control. A total of 16 horses, aged 8-20years, with heaves were included in the study. Complete examinations were performed on Day 0 (before treatment), Day 13 (after treatment) and Day 30. Clinical variables, arterial blood gases, mucus scoring and carina evaluation (during endoscopy), and bronchoalveolar lavage (BAL) cytological analysis were all assessed. The horses were randomly assigned to receive either oral prednisolone (1mg/kg) or IM dex...
IgE-bearing cells in bronchoalveolar lavage fluid and allergen-specific IgE levels in sera from RAO-affected horses. Recurrent airway obstruction (RAO) is a common condition in stabled horses characterized by small airway inflammation, airway neutrophilia and obstruction following exposure of susceptible horses to mouldy hay and straw and is thus regarded as a hypersensitivity reaction to mould spores. However, the role of immunoglobulin E antibodies (IgE) in the pathogenesis of RAO is unclear. We hypothesized that the number of cells with receptor-bound IgE in bronchoalveolar lavage fluid (BALF) and IgE levels in serum would be higher in RAO-affected than in healthy horses living in the same environment. Th...
Pulmonary disposition of erythromycin, azithromycin, and clarithromycin in foals. The objectives of the present study were to determine and compare the pulmonary disposition of azithromycin, clarithromycin, and erythromycin in foals. A single dose (10 mg/kg) of azithromycin, clarithromycin, or erythromycin was administered intragastrically to six healthy 1- to 3-month-old foals using an orthogonal design. Activity of the drugs was measured in serum, pulmonary epithelial lining fluid (PELF), and bronchoalveolar lavage (BAL) cells by use of a microbiologic assay. Peak drug activity in PELF was significantly higher in foals treated with clarithromycin (48.96+/-13.26 microg/mL)...
Influx of neutrophils and persistence of cytokine expression in airways of horses after performing exercise while breathing cold air. To determine effects of exercise performed while breathing cold air on expression of cytokines and influx of neutrophils in airways of horses. Methods: 9 adult horses. Methods: In a crossover study, bronchoalveolar lavage fluid (BALF) was obtained 24 and 48 hours after each of 2 submaximal exercise sessions performed by horses while breathing warm (25 degrees C) or cold (-5 degrees C) air. Total and differential nucleated cell counts were determined for each BALF sample. Relative mRNA expression of cytokines in BALF cells was quantified by use of a reverse transcription-PCR assay. Results: Hor...
Quantitative determination of the macrolide antibiotic tulathromycin in plasma and broncho-alveolar cells of foals using tandem mass spectrometry. The long-acting antibiotic tulathromycin is on the marked for treatment of pulmonary infection of cattle, swine and horses. To measure disposition and distribution of tulathromycin in foals, a high throughput method was developed for horse plasma (calibration range: 0.006-0.8 microg/mL) and broncho-alveolar cells (calibration range: 0.1-4.0 microg/10(9)cells) using tandem mass spectrometry. Tulathromycin was extracted from plasma and broncho-alveolar fluid using cation exchange cartridges with acetonitrile/ammonia (95:5, v/v). The chromatography was performed isocratically with a mobile phase ...
Lung surfactant function and composition in neonatal foals and adult horses. Lung surfactant function and composition are varied and adapted to the specific respiratory physiology of all mammalian species. Objective: Lung surfactant function and composition are different in neonatal foals as compared to adult horses. Methods: Six adult horses, 7 term foals (<24 hours old), and 4 premature foals were used. Animals were part of the Auburn University teaching herd except for 3 client-owned premature foals. Methods: Bronchoalveolar lavage fluid (BALF) was obtained from all animals. Ultracentrifugation of cell-free BALF separated surfactant into crude surfactant pellets ...
Elevated amount of Toll-like receptor 4 mRNA in bronchial epithelial cells is associated with airway inflammation in horses with recurrent airway obstruction. Recurrent airway obstruction (RAO) is characterized by neutrophilic airway inflammation and 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 with controls and with R...
Early onset airway obstruction in response to organic dust in the horse. Equine recurrent airway obstruction (RAO) has been used as a naturally occurring model of human asthma. However, it is unknown whether there is an early-phase response in RAO. The aim of this study was to determine whether exposure to organic dust induces immediate changes in lung function in RAO-affected horses, which could be mediated by airway mast cells. Six RAO-affected horses in remission and six control horses were challenged with hay-straw dust suspension by nebulization. Total respiratory resistance at 1 Hz, measured by forced oscillation, was increased from 0.62 +/- 0.09 cmH(2)O.l(-1...
Effects of the bronchoalveolar lavage procedure on lung function in horses with clinical exacerbation of recurrent airway obstruction. To evaluate whether bronchoalveolar lavage (BAL) alters respiratory mechanics of horses with recurrent airway obstruction (ie, heaves) over a 48-hour period. Methods: 6 horses affected with heaves. Methods: Horses were subjected to a complete BAL procedure, which included sedation with xylazine and butorphanol, intratracheal administration of lidocaine, and instillation and aspiration of two 250-mL boluses of saline (0.9% NaCl) solution through an endoscope (study 1). To evaluate the effects of saline solution, horses were subjected to the same procedure without saline solution instillation an...
Myeloperoxidase concentration in bronchoalveolar lavage fluid from healthy horses and those with recurrent airway obstruction. The aim of this work was to measure the myeloperoxidase (MPO) concentration in bronchoalveolar lavage (BAL) fluid collected from horses with recurrent airway obstruction (RAO), both in crisis and in remission, as well as from healthy horses. Seven horses with RAO were exposed to moldy hay until the maximum change in pleural pressure was greater than 1.5 kPa. At that point, BAL was performed, and the total cell counts and percentages in the fluid were immediately determined. To measure the MPO concentration in BAL-fluid supernatant, we used a specific enzyme-linked immunosorbent assay with poly...
Pharmacokinetics of clarithromycin and concentrations in body fluids and bronchoalveolar cells of foals. To determine pharmacokinetics of clarithromycin and concentrations in body fluids and bronchoalveolar (BAL) cells of foals. Methods: 6 healthy 2-to 3-week-old foals. Methods: In a crossover design, clarithromycin (7.5 mg/kg) was administered to each foal via IV and intragastric (IG) routes. After the initial IG administration, 5 additional doses were administered IG at 12-hour intervals. Concentrations of clarithromycin and its 14-hydroxy metabolite were measured in serum by use of high-performance liquid chromatography. A microbiologic assay was used to measure clarithromycin activity in seru...
Comparison of the antioxidant status in tracheal and bronchoalveolar epithelial lining fluids in recurrent airway obstruction. Following a period of airway inflammation the clearance of inflammatory cells along the mucociliary escalator may impose a considerable oxidant load on the trachea. Objective: To determine the degree of oxidative stress in tracheal epithelial lining fluid (ELF) in comparison to that present in peripheral airways after an acute exposure to organic dust. Methods: Tracheal wash fluid and bronchoalveolar lavage fluid (BALF) were collected for cytology and antioxidant analyses from 6 recurrent airway obstruction (RAO)-affected horses and 6 healthy control horses before and after stabling on straw b...
The effect of aerosolized and intravenously administered clenbuterol and aerosolized fluticasone propionate on horses challenged with Aspergillus fumigatus antigen. Beta-agonists have been shown to display anti-inflammatory properties in several experimental models. The aim of this study was to investigate the anti-inflammatory properties of clenbuterol (CB), administered either intravenously or by aerosol, in comparison with fluticasone propionate (FP) in recurrent airway obstruction (RAO)-susceptible horses. Eight horses, of which five were known to be susceptible to RAO, underwent an inhalation challenge with Aspergillus fumigatus (AF) antigen and were treated with CB intravenously, CB by aerosol, or FP by aerosol. Twenty-four hours after the challenge...
Rapid, multiwell colorimetric assay for measuring neutrophil chemoattractant activity in bronchoalveolar lavage fluid of horses with recurrent airway obstruction. The criteria used to diagnose recurrent airway obstruction (RAO) in affected horses include demonstration of reversible lower airway obstruction and greater than 25% neutrophils in bronchoalveolar lavage fluid (BALF). Additional objective laboratory tests are needed to improve diagnostic accuracy and to monitor response to treatment. The goal of this study was to determine if neutrophil chemoattractant activity of BALF could be measured by using a previously described, rapid, multiwell colorimetric assay for chemotaxis. In this assay, neutrophils that have migrated through a membrane filter ar...
DNA binding activity of transcription factors in bronchial cells of horses with recurrent airway obstruction. Horses with recurrent airway obstruction (RAO) present many similarities with human asthmatics including airway inflammation, hyperresponsiveness, reversible obstruction, and increased NF-kappaB expression. Studies in experimental asthma models have shown that transcriptions factors such as activator protein-1 (AP-1), GATA-3, cyclic AMP response element binding protein (CREB) and CAAT/enhancer binding protein (C/EBP) may also play an important role in airway inflammation. The purpose of this study was to measure DNA binding activity of these transcription factors in the airways of horses with ...
Comparison of four staining methods for detection of mast cells in equine bronchoalveolar lavage fluid. Mast cells normally are present in equine bronchoalveolar lavage fluid (BALF), but usually represent <2% of all cells in healthy horses. An increased percentage of mast cells has been associated with airway hyperactivity and inflammatory airway diseases, but marked differences are reported between studies in normal and diseased horses. Because an abnormal mast cell count may be of clinical relevance, we compared the ability of a fast Romanowsky method to stain mast cell granules with that of 3 metachromatic stains: automated Romanowsky, May-Grünwald Giemsa, and toluidine blue stains. The B...
Effect of beclomethasone dipropionate and dexamethasone isonicotinate on lung function, bronchoalveolar lavage fluid cytology, and transcription factor expression in airways of horses with recurrent airway obstruction. Glucocorticoid (GC) therapy is recognized to be effective for the treatment of recurrent airway obstruction (RAO) in horses. Anti-inflammatory properties of GC are thought to be mediated by suppression of inflammatory gene expression via inhibition of transcription factors such as nuclear factor-kappaB (NF-kappaB) and activator protein-1 (AP-1). The purpose of this study was to evaluate the effect of low-dose inhaled beclomethasone dipropionate and injectable dexamethasone 21-isonicotinate on clinical signs, pulmonary function, airway cytology, and activity of NF-kappaB and AP-1 in bronchial c...
Time-dependent alterations in gene expression of interleukin-8 in the bronchial epithelium of horses with recurrent airway obstruction. 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). Methods: 8 RAO-susceptible horses and 9 control horses. Methods: 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 expres...
Lack of clinical efficacy of a phosphodiesterase-4 inhibitor for treatment of heaves in horses. Phosphodiesterase-4 (PDE 4) enzyme inhibitors have been shown to have anti-inflammatory properties in various animal disease processes and therefore could be effective drugs for the treatment of equine airway diseases. The purpose of this study was to evaluate the efficacy and adverse effects of the PDE 4 inhibitor L-826,141 in horses with heaves. In a blinded parallel design, horses with heaves exposed daily to moldy hay were given a placebo for 14 days and then administered either L-826,141 (n = 6; loading dose of 1 mg/kg IV followed by 0.5 mg/kg IV q48h) or dexamethasone (n = 6; 0.04 mg/kg ...
The role of alveolar macrophages in the pathogenesis of recurrent airway obstruction in horses. 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 ho...
Improvement of the lung function of horses with heaves by treatment with a botanical preparation for 14 days. The effects of an oral preparation containing a mixture of extracts from yellow gentian, garden sorrel, cowslip, verbena and common elder on the lung function of nine horses suffering from heaves were determined in a longitudinal crossover study. The horses were divided at random into a group of five (group 1) and a group of four (group 2). The horses in group 1 were each given 15 tablets of the preparation twice daily, while the horses in group 2 were left untreated. Fourteen days later, the horses in group 2 were given the same course of treatment while the horses in group 1 were left untrea...
Membrane switch hypothesis. 2. Domain structure of phagocytes in horses with recurrent airway obstruction. The mechanism of recurrent airway obstruction (RAO) in horses was investigated by measuring the membrane domain structure and oxy-redoxy activity in phagocytes isolated from bronchoalveolar lavage fluid (BAL) and from the blood of healthy and RAO horses by electron paramagnetic resonance (EPR). Differences in the activity of intracellular antioxidant enzymes CAT, GPx, and SOD measured in phagocytes of RAO horses in comparison to healthy horses showed that the phagocytes were affected by oxidative stress. In comparison with polymorphonuclear leukocytes (phagocytes) from the blood of healthy hor...
Radiographic scoring lacks predictive value in inflammatory airway disease. Diagnosis of inflammatory airway disease (IAD) currently rests upon the results of bronchoalveolar lavage (BAL) cytology, lung function testing and histamine bronchoprovocation (HBP), none of which provides direct information about structural change in the lung. Objective: That thoracic radiography might better portray structural change in the lungs and therefore offer a good clinical assessment of IAD. Methods: A radiographic scoring system was developed to assess the extent of bronchial and interstitial pattern on thoracic radiographs in the dorsocaudal, dorsocranial and caudoventral regions...
Randomized, controlled study of inhaled fluticasone propionate, oral administration of prednisone, and environmental management of horses with recurrent airway obstruction. To determine whether administration of glucocorticoids provides additional benefits to environmental management of horses with recurrent airway obstruction (RAO). Methods: 28 horses with RAO. Methods: Horses were classified as having mild, moderate, or severe RAO. Within each category, horses were randomly assigned to receive inhaled fluticasone propionate, inhaled control substance, or oral administration of prednisone. During the 4-week study, horses were maintained outdoors and fed a pelleted feed. Clinical scores, pulmonary function, results of cytologic examination of bronchoalveolar lava...