The bronchi are part of the lower respiratory tract in horses, serving as air passages that conduct inhaled air from the trachea into the lungs. These tubular structures branch into smaller bronchioles, leading to the alveoli where gas exchange occurs. The health and function of the bronchi are critical for maintaining respiratory efficiency and overall equine health. Conditions affecting the bronchi, such as bronchitis or bronchoconstriction, can impact a horse's respiratory performance and are often a focus in equine veterinary medicine. This page compiles peer-reviewed research studies and scholarly articles that explore the anatomy, physiology, and pathophysiology of the bronchi in horses, as well as diagnostic and therapeutic approaches for bronchial conditions.
Menozzi A, Pozzoli C, Poli E, Delvescovo B, Serventi P, Bertini S.We investigated the effects of nonselective muscarinic antagonist (atropine) and of selective muscarinic subtype 1 (M1), 2 (M2), 3 (M3) antagonists (VU0255035, methoctramine, pFHHSiD, respectively) on the contractions evoked by electrical field stimulation (EFS) or by exogenous ACh in isolated horse bronchial muscle. Atropine completely inhibited neurogenic contractions in a concentration-dependent fashion, whereas selective muscarinic antagonists induced relevant modifications only at the highest concentration tested. Experiments with selective muscarinic antagonists in combination showed tha...
Pacheco AP, Paradis MR, Hoffman AM, Hermida P, Sanchez A, Nadeau JA, Tufts M, Mazan MR.Despite the increasing number of geriatric horses attended by veterinarians, there is a lack of understanding of aging-related changes on the respiratory system of horses. Objective: To identify aging-related changes on the respiratory function and bronchoalveolar lavage fluid (BALF) cytology of horses. Methods: Fifteen healthy young adult (2-11 years) and 16 healthy aged (≥20 years) horses. Methods: The respiratory system was examined by measurement of arterial blood gases (ABG), use of respiratory inductive plethysmography (RIP) for assessment of breathing pattern and ventilatory paramet...
Padoan E, Ferraresso S, Pegolo S, Castagnaro M, Barnini C, Bargelloni L.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 ex...
Goraya K, Iqbal Z, Sajid M, Muhammad G, Ain QU, Saleem M.Plants have widely been used and documented for their therapeutic potential in many parts of the world. There are, however, few reports on the use of plants for the treatment of diseases of equines. To this end, participatory epidemiology and rapid rural appraisal techniques were used to document the plants having pharmacotherapeutic significance against different ailments of equines in selected population of Punjab, Pakistan. Methods: A survey was conducted to interview a total of 450 respondents (150 from each of the districts of Faisalabad, Lahore and Sargodha of Pakistan) to collect inform...
Schwab U, Caldwell S, Matychak MB, Felippe J.We developed a 3-D equine bronchial epithelial cell (BEC) culture that fully differentiates into ciliary beating and mucus producing cells. Using this system, we evaluated how mucus affects the phagocytic activity of macrophages. Adult horse monocyte-derived macrophages were incubated with Rhodococcus equi for 4h either in the mucus layer of in vitro generated airway epithelium or on collagen coated membranes. Using light and electron microscopy, we noted that the number of macrophages with intracellular bacteria, and the number of intracellular bacteria per macrophage were lower in the presen...
Wilson ME, Berney C, Behan AL, Robinson NE.Lidocaine decreases neutrophilic inflammation in models of acute lung injury and decreases inflammation in asthmatic patients. Neutrophilic bronchiolitis develops in recurrent airway obstruction (RAO), but it remains unknown if lidocaine infusion decreases neutrophil migration into the airways. Objective: Lidocaine decreases neutrophilic inflammation as measured in BALF in RAO-affected horses. Methods: Six RAO-susceptible horses in remission. Methods: In a randomized cross-over design, horses received lactated Ringer's solution (LRS) IV or lidocaine hydrochloride IV with a minimum of 4 weeks a...
Fugazzola M, Barton AK, Niedorf F, Kietzmann M, Ohnesorge B.Glucocorticoids have been proven to be effective in the therapy of recurrent airway obstruction (RAO) in horses via systemic as well as local (inhalative) administration. Elective analysis of the effects of this drug on bronchoconstriction in viable lung tissue offers an insight into the mechanism of action of the inflammatory cascade occurring during RAO which is still unclear. The mechanism of action of steroids in treatment of RAO is thought to be induced through classical genomic pathways. We aimed at electively studying the effects of the glucocorticoid beclomethasone dipropionate on equi...
Tsuchiya T, Hobo S, Endo Y, Narita S, Sakamoto K.To evaluate effects of a single dose of enrofloxacin (5 mg/kg, IV) on body temperature and tracheobronchial neutrophil count in healthy Thoroughbreds premedicated with interferon-α and undergoing long-distance transportation. Methods: 32 healthy Thoroughbreds. Methods: All horses received interferon-α (0.5 U/kg, sublingually, q 24 h) as an immunologic stimulant for 2 days before transportation and on the day of transportation. Horses were randomly assigned to receive enrofloxacin (5 mg/kg, IV, once; enrofloxacin group) or saline (0.9% NaCl) solution (50 mL, IV, once; control group) ≤ 1 hou...
Leclere M, Lavoie-Lamoureux A, Joubert P, Relave F, Setlakwe EL, Beauchamp G, Couture C, Martin JG, Lavoie JP.Recent studies suggest that airway smooth muscle remodeling is an early event in the course of asthma. Little is known of the effects of long-term antigen avoidance and inhaled corticosteroids on chronically established airway remodeling. We sought to measure the effects of inhaled corticosteroids and antigen avoidance on airway remodeling in the peripheral airways of horses with heaves, a naturally occurring asthma-like disease. Heaves-affected adult horses with ongoing airway inflammation and bronchoconstriction were treated with fluticasone propionate (with and without concurrent antigen av...
Venugopal C, Mariappan N, Holmes E, Kearney M, Beadle R.To determine and compare the reactive oxygen and nitrogen species (ROS and RNS) in pulmonary tissues of horses affected with recurrent airway obstruction (RAO) and clinically healthy horses, and to evaluate the effectiveness of potential therapeutic agents in reducing ROS and RNS in the tissues of these horses. Objective: We hypothesised that RAO-affected horses would have high levels of reactive species and that the test agents would reduce them. The objectives were as follows: 1) to determine the level of ROS and RNS in pulmonary tissues (bronchial and arterial rings) of RAO-affected and cli...
Klukowska-Rötzler J, Marti E, Lavoie JP, Ainsworth DM, Gerber V, Zurbriggen A, Janda J.Thymic stromal lymphopoietin (TSLP) is a cytokine involved in lymphocyte development. In humans and mice, TSLP drives the differentiation of T helper 2 (Th2) cells and the development of allergic inflammation. The equine TSLP gene has been previously identified and characterized, but its role in the pathogenesis of equine allergic diseases is not known. Our objective was to assess the expression of TSLP in bronchoalveolar lavage (BAL) cells and in primary bronchial epithelial cells (BEC) isolated from horses with recurrent airway obstruction (RAO). RNA was isolated from BAL cells sampled from ...
Ainsworth DM, Reyner CL.To examine the effects of in vitro exposure to solutions of autologous horse blood (AHB) and autologous horse serum (AHS) on expressions of selected cytokine genes in equine primary bronchial epithelial cell (BEC) cultures and to contrast these responses to those induced in BEC cultures by endotoxin and hay dust. Methods: BEC cultures established from bronchi of 6 healthy horses. Methods: 5-day-old BEC cultures were treated with PBS solution, AHB (2 concentrations), AHS, hay dust solution, and lipopolysaccharide solution for 24 hours. Gene expressions of interleukin (IL)-8, IL-1β, chemokine (...
Koblinger K, Nicol J, McDonald K, Wasko A, Logie N, Weiss M, Léguillette R.Comprehensive endoscopic scoring of the upper and lower airways for inflammation has not been critically assessed among a large population of horses. The relationship between upper and lower airways described in humans by the "one airway, one disease" concept might also apply to horses. Objective: To evaluate if an association exists between endoscopic inflammatory scores and mucus scores of upper and lower airways and to investigate if endoscopic findings correlate with the lower airway inflammation measured by bronchoalveolar lavage (BAL) cytology. Methods: Prospective field study. Pharyngit...
Leclere M, Lavoie-Lamoureux A, Lavoie JP.Animal models have been developed to investigate specific components of asthmatic airway inflammation, hyper-responsiveness or remodelling. However, all of these aspects are rarely observed in the same animal. Heaves is a naturally occurring disease of horses that combines these features. It is characterized by stable dust-induced inflammation, bronchospasm and remodelling. The evaluation of horses during well-controlled natural antigen exposure and avoidance in experimental settings allows the study of disease mechanisms in the asymptomatic and symptomatic stages, an approach rarely feasible ...
Begg AP, Reece RL, Hum S, Townsend W, Gordon A, Carrick J.Analysis of pathology results from the 2007 equine influenza (EI) outbreak in Australia indicate that young foals in naïve horse populations are prone to developing broncho-interstitial pneumonia, and that this can be a rare manifestation of EI virus infection in mature horses. All horses may develop secondary bacterial bronchopneumonia, with mature horses more likely to die. EI outbreaks among heavily pregnant mares can result in increased neonatal losses because of premature placental separation and dystocia causing fetal hypoxia.
Abraham G, Zizzadoro C, Kacza J, Ellenberger C, Abs V, Franke J, Schoon HA, Seeger J, Tesfaigzi Y, Ungemach FR.Horses develop recurrent airway obstruction (RAO) that resembles human bronchial asthma. Differentiated primary equine bronchial epithelial cells (EBEC) in culture that closely mimic the airway cells in vivo would be useful to investigate the contribution of bronchial epithelium in inflammation of airway diseases. However, because isolation and characterization of EBEC cultures has been limited, we modified and optimized techniques of generating and culturing EBECs from healthy horses to mimic in vivo conditions. Results: Large numbers of EBEC were obtained by trypsin digestion and successfull...
Boly R, Dessy S, Kohnen S, Kini F, Lompo M, Mouithys-Mickalad A, Guissou IP, Dubois J, Deby-Dupont G, Serteyn D, Franck T.Agelanthus dodoneifolius DC Danser (Loranthaceae) is used for the treatment of various diseases including asthma. The aqueous and hydroalcoholic extracts have been reported to have anti-inflammatory, spasmolytic and bronchorelaxant activities. The present study investigates the effects of the aqueous decoction and the diethyl ether, ethyl acetate and butanolic fractions of Agelanthus dodoneifolius DC Danser (Loranthaceae) on reactive oxygen species (ROS) production and myeloperoxidase (MPO) release by phorbol 12-myristate 13-acetate (PMA)-stimulated equine neutrophils and on purified equine MP...
Millerick-May ML, Karmaus W, Derksen FJ, Berthold B, Holcombe SJ, Robinson NE.Airway inflammation and mucus in the trachea are common in racehorses. Fine airborne particles can initiate and coarse particles can worsen airway inflammation in man and in animal models of airway disease. The regional and seasonal distribution of particles of different sizes has never been investigated in American racing stables. Objective: To determine the regional and seasonal concentration and number of airborne particles of different sizes in racing stables. Methods: Direct reading instruments were used to determine the mass concentration and numbers of particles 3 times daily (early mor...
Matera MG, Calzetta L, Rogliani P, Bardaro F, Page CP, Cazzola M.Equine obstructive pulmonary disease, also known as heaves or recurrent airway obstruction (RAO) is a common equine pulmonary disease with some similarities to human asthma and COPD, which represents a major cause of morbidity and loss of lung performance. Salbutamol has been widely used for the treatment of human airway diseases and has usually been prepared as the racemic form of the drug. However, recently the R-enantiomer of salbutamol has been introduced into clinical practice in the treatment of asthma in humans and this has been suggested to be an improvement on the racemic form of the ...
Goncarovs KO, Miskovic Feutz M, Perez-Moreno C, Couetil LL.One proposed nonmedical therapy for recurrent airway obstruction (RAO) in horses is a handheld acoustic device that propels sound waves from the nose down the tracheobronchial tree where it is intended to dislodge mucous and relax bronchospasm, permitting clearance of mucoid secretions. Objective: To evaluate the effectiveness and safety of this device when used as per the manufacturer's recommendations as a treatment for RAO. Methods: Nine adult horses previously diagnosed with RAO. Methods: Prospective, cross-over clinical trial. Horses were exposed to a dusty environment until airway obstru...
Leclere M, Lavoie-Lamoureux A, Gélinas-Lymburner E, David F, Martin JG, Lavoie JP.Recent studies suggest that airway smooth muscle remodeling is an early event in asthma, but whether it remains a dynamic process late in the course of the disease is unknown. Moreover, little is known about the effects of an antigenic exposure on chronically established smooth muscle remodeling. We measured the effects of antigenic exposure on airway smooth muscle in the central and peripheral airways of horses with heaves, a naturally occurring airway disease that shares similarities with chronic asthma. Heaves-affected horses (n = 6) and age-matched control horses (n = 5) were kept on pastu...
Giordano A, Meazza C, Salvadori M, Paltrinieri S.Exercise-induced pulmonary hemorrhage (EIPH) commonly occurs in race horses. Thromboelastometry (TEM) investigates the whole hemostatic process by evaluating the viscoelastic properties of the blood clot from its formation to fibrinolysis. The aim of this study was to assess whether horses with EIPH have abnormal thromboelastometric profiles. Intrinsic and extrinsic pathways, fibrinogen activity and fibrinolysis were investigated by TEM before and after the race in negative controls and in horses on which EIPH was confirmed by bronchoscopy. Compared with controls, horses with EIPH had an incre...
Muranaka M, Yamanaka T, Katayama Y, Hidari K, Kanazawa H, Suzuki T, Oku K, Oyamada T.It is strongly suspected that equine influenza virus (EIV) is the origin of canine influenza virus (CIV, H3N8), which was first isolated in U.S.A. in 2004, on the basis of phylogenetic analyses. Although the distribution of influenza virus sialoreceptors seems to be associated with this interspecies transmission, there have been scant data of comparison about distributions of sialoreceptors on the whole respiratory tract between horses and dogs. We examined the histological distribution of influenza virus sialoreceptors on the upper and lower respiratory tract in detail in both animals using d...
Furness MC, Bienzle D, Caswell JL, Delay J, Viel L.Recurrent airway obstruction (RAO) in the horse is a disease characterized by reversible bronchoconstriction and by mucus and neutrophil accumulation in the airways. It has been hypothesized that in horses with RAO, remodeling changes occur that are similar to those described in humans with asthma. Although collagen fibrils are present surrounding normal airways, they are a prominent feature of airway remodeling in human asthma with evidence of enhanced collagen III and I fibril deposition. An immunolabeling method was developed to identify collagen I and III in equine lung and to describe the...
Barton AK, Niedorf F, Gruber AD, Kietzmann M, Ohnesorge B.Equine precision cut lung slices (PCLS) were used to evaluate the ability of several pharmacologic compounds, parasympatholytics atropine, ipratropium, tiotropium and phosphodiesterase (PDE) 4-inhibitor cilomilast, to inhibit methacholine (MCh) induced bronchial constriction. The study war performed using vital lung samples from 20 horses, harvested immediately after euthanasia and lung examination.Tissue samples from the cranial, caudal and accessory lobe were taken for histological examination. Viability in PCLS of 250 +/- 20 microm was confirmed by observation of cilia movement and bronchia...
Matsuda K, Qiu Y, Furuse T, Kawamura Y, Yokoyama D, Kato A, Taniyama H.This report documents an unusual case of congenital foregut cyst with dysphagia and stridor in a Thoroughbred foal. Histologically, the bilocular cyst, near the junction of larynx and trachea, had an epithelial lining of bronchogenic and esophageal origin. Concomitant malformation of the laryngeal muscles and cartilage resulted in a combination of anomalies that have not been reported in the human or veterinary literature.
Schwab UE, Fulcher ML, Randell SH, Flaminio MJ, Russell DG.We describe a method for creating differentiated equine bronchial epithelial cell cultures that can be used for in vitro studies including airway disease mechanisms and pathogen-host interactions. Our method is based on the culturing of human tracheobronchial epithelial cells at an air-liquid interface (ALI) in specific serum-free, hormone-supplemented medium. Bronchial epithelial cells are isolated and grown on T-Clear® insert membranes. Within 2 to 3 wk, cells differentiate into ciliated and mucus producing cells as demonstrated by confocal and electron microscopy. Furthermore, the demonstr...
Ramery E, Fievez L, Fraipont A, Bureau F, Lekeux P.The long pentraxin 3 (PTX3) plays an important role in host defence and its over-expression may contribute to airway injury. The aim of the present study was therefore to characterize in more detail PTX3 and its expression in the horses' airway. Six healthy horses and six horses affected by recurrent airway obstruction (R.A.O.) were submitted to a dusty environment challenge. PTX3 DNA and cDNA were cloned and sequenced. PTX3 expression was evaluated by RT-qPCR, Western blotting and immunohistochemistry in bronchoalveolar lavage fluid (BALF) cells, BALF supernatant and bronchial epithelial cell...
Nolen-Walston RD, Kuehn H, Boston RC, Mazan MR, Wilkins PA, Bruns S, Hoffman AM.Inflammatory airway disease has a high prevalence in horses, but is often a diagnostic challenge. Flowmetric plethysmography and histamine bronchoprovocation (FP/HBP) is a simple and effective tool for diagnosis, but reproducibility of these measurements made over time has not been established. Objective: We hypothesize that the measurement of airway responsiveness in horses using FP/HBP is consistent over both short and long periods of time. Methods: Twenty-nine healthy adult horses from 2 university herds. Methods: In this prospective experimental study, airway responsiveness was determined ...
Elfman L, Riihimäki M, Pringle J, Wålinder R.Many people spend considerable amount of time each day in equine stable environments either as employees in the care and training of horses or in leisure activity. However, there are few studies available on how the stable environment affects human airways. This study examined in one horse stable qualitative differences in indoor air during winter and late summer conditions and assessed whether air quality was associated with clinically detectable respiratory signs or alterations to selected biomarkers of inflammation and lung function in stable personnel. Methods: The horse stable environment...
Lakritz J, Wilson WD, Berry CR, Schrenzel MD, Carlson GP, Madigan JE.Twenty-three foals, between 1 and 7 months old, with signs of acute respiratory distress, were examined at the Veterinary Medical Teaching Hospital (VMTH), University of California, Davis, between 1984 and 1989. Characteristic features included sudden onset of severe respiratory distress and tachypnea, cyanosis unresponsive to nasal oxygen, pyrexia, hypoxemia, hypercapneic respiratory acidosis, poor response to treatment, and histopathologic lesions of bronchiolitis and bronchointerstitial pneumonia. Seven of the 23 foals were normal before the onset of respiratory distress, 3 foals were found...
Franchini M, Gilli U, Akens MK, Fellenberg RV, Bracher V.Chronic obstructive pulmonary disease (COPD) is defined as a chronic obstructive inflammatory disease affecting the small airways associated with hay dust exposure (Lowell, F.C., 1964. Observation on heaves. An asthma like syndrome in the horse, J. Allergy 35, 322-330). The disease corresponds histopathologically to a chronic bronchiolitis (Gerber, H., 1973. Chronic pulmonary disease in the horse, Equine Vet. J. 5, 26-33; Winder, N.C., Grünig, G., Hermann, M., Howald, B., von Fellenberg, R., 1989. Comparison of respiratory secretion cytology and pulmonary histology in horses, J. Vet. Med., A3...
Muranaka M, Yamanaka T, Katayama Y, Hidari K, Kanazawa H, Suzuki T, Oku K, Oyamada T.It is strongly suspected that equine influenza virus (EIV) is the origin of canine influenza virus (CIV, H3N8), which was first isolated in U.S.A. in 2004, on the basis of phylogenetic analyses. Although the distribution of influenza virus sialoreceptors seems to be associated with this interspecies transmission, there have been scant data of comparison about distributions of sialoreceptors on the whole respiratory tract between horses and dogs. We examined the histological distribution of influenza virus sialoreceptors on the upper and lower respiratory tract in detail in both animals using d...
Couëtil LL, Art T, de Moffarts B, Becker M, Mélotte D, Jaspar F, Bureau F, Lekeux P.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 ...
Magno M.This review considers the similarities and difference between several animal species to determine which are most appropriate for studies of the human bronchial circulation in health and disease. The subgross anatomy of the sheep, cow, pig and horse appear to be similar to that of humans. These species have a major bronchial artery with a consistent location. In humans and other species, there is evidence of anastomoses between the bronchial and coronary circulations. The bronchial circulation provides nutrient supply to the neural structures of all species. The bronchial arteries themselves ar...
Riihimäki M, Raine A, Pourazar J, Sandström T, Art T, Lekeux P, Couëtil L, Pringle J.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-alpha, 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 compari...
Bessonnat A, Hélie P, Grimes C, Lavoie JP.There is a remodeling of the central airways in horses with severe asthma but whether a similar process occurs in horses with the mild or moderate asthma (MMA) is unknown. Objective: To evaluate lesions affecting the central airways of horses with MMA. Methods: Twelve horses with MMA and 8 control horses. Methods: Case-control retrospective study of horses classified as MMA affected or controls based on history and bronchoalveolar lavage fluid cytology. Endobronchial biopsies were analyzed using histomorphometry and a semiquantitative histologic scoring system. Results: Histomorphometry identi...
Gunson DE, Sweeney CR, Soma LR.Pathologic changes are described in 11 horses that died during racing or training; 9 died of acute pulmonary hemorrhage (exercise-induced pulmonary hemorrhage), 1 died of exsanguination, and 1 died of CNS trauma. Cardiac lesions were not found in any horse. Severe engorgement of pulmonary vessels, with hemorrhage into alveoli, airways, interstitium, and subpleural tissues, was observed in all 9 horses that died of exercise-induced pulmonary hemorrhage. Infiltration of eosinophils and/or lymphocytes around vessels and airways was seen in 6 horses. Focally extensive fibrosis was observed in the ...
Broadstone RV, LeBlanc PH, Derksen FJ, Robinson NE.The in vitro contractile and relaxant responses of tracheal smooth muscle strips (TSM) and third-generation bronchi (3B) of control horses and horses with recurrent obstructive disease (heaves) were compared. Acetylcholine (ACH) sensitivity of the diseased tissues was less than that of tissues from control horses, especially at the level of the third generation (EC50 controls 15 +/- 11 microM vs 81 +/- 17 microM for heaveys). Despite tracheal and bronchial hyporesponsiveness to ACH, these tissues from heavey horses were hyperresponsive to EFS. The inhibitory effect of isoproterenol and electri...
Mainguy-Seers S, Lavoie JP.Despite substantial research efforts to improve the treatment and outcome of horses with asthma, glucocorticoids (GC) remain the cornerstone of drug treatment of this prevalent disease. The high efficacy of GC to relieve airway obstruction explains their extensive use despite potential deleterious effects. However, much is yet to be uncovered concerning GC use in horses with asthma, including the comparative efficacy of the different drugs, the determination of minimal effective doses and the mechanisms underlying their variable modulation of airway inflammation. The objectives of this structu...
Abs V, Bonicelli J, Kacza J, Zizzadoro C, Abraham G.Interaction between epithelial cells and fibroblasts play a key role in wound repair and remodelling in the asthmatic airway epithelium. We present the establishment of a co-culture model using primary equine bronchial epithelial cells (EBECs) and equine bronchial fibroblasts (EBFs). EBFs at passage between 4 and 8 were seeded on the bottom of 24-well plates and treated with mitomycin C at 80% confluency. Then, freshly isolated (P0) or passaged (P1) EBECs were seeded on the upper surface of membrane inserts that had been placed inside the EBF-containing well plates and grown first under liquid...
Crispe EJ, Secombe CJ, Perera DI, Manderson AA, Turlach BA, Lester GD.Exercise-induced pulmonary haemorrhage (EIPH) is considered a progressive disease based on histopathology, but it is unknown if tracheobronchoscopic EIPH severity worsens over time. Objective: The aim of this study was to examine tracheobronchoscopic EIPH changes over time in a population of Thoroughbred racehorses. A secondary aim was to identify factors that affect changes in tracheobronchoscopic EIPH severity between observations. Methods: Prospective, longitudinal, observational cross-sectional study. Methods: Thoroughbred racehorses were examined with tracheobronchoscopy no earlier than 3...
Vandenput S, Votion D, Duvivier DH, Van Erck E, Anciaux N, Art T, Lekeux P.The aim of this study was to evaluate the respiratory function of horses affected with chronic obstructive pulmonary disease (COPD) when maintained in a barn on wood shavings and fed grass silage for a period of 6 weeks. The mechanics of breathing, blood gas analysis and bronchial reactivity were examined on five horses with COPD at the end of the environment-controlled period (Period B) and the results compared with values obtained after 2 months at pasture (Period A) and after the onset of clinical signs of acute crisis (Period C). The results showed that clinical and functional parameters w...
Riihimäki M, Lilliehöök I, Raine A, Berg M, Pringle J.The aim of this study was to assess clinical signs and altered pulmonary cell expression of cytokines related to eosinophil kinetics in horses with pulmonary eosinophilia. Pulmonary eosinophilia was detected by bronchoalveolar lavage (BAL) in a group of standardbreds in training. Horses had detailed clinical examination, bronchoscopy, endobronchial biopsy and BAL on three occasions at approximately 6 month intervals. During the second sampling period BAL eosinophils were significantly elevated (p>0.010), with five horses having from 5% to 37% eosinophils in BAL. Neither detailed clinical ex...
Mönki J, Saastamoinen M, Karikoski N, Norring M, Rajamäki M, Mykkänen A.The effects of bedding material on air quality are important amongst horses worldwide. Respiratory diseases, especially equine asthma, are highly prevalent with air hygiene playing a major role on the pathophysiology of these diseases. The objective of our study was to investigate the effects of four bedding materials on the respiratory signs, tracheal mucus score, and tracheal wash (TW) and bronchoalveolar lavage fluid (BALF) cytology in healthy adult horses. The study design was a prospective controlled cross-over study, and the subjects were healthy adult riding school horses ( = 32) from a...
Begg AP, Reece RL, Hum S, Townsend W, Gordon A, Carrick J.Analysis of pathology results from the 2007 equine influenza (EI) outbreak in Australia indicate that young foals in naïve horse populations are prone to developing broncho-interstitial pneumonia, and that this can be a rare manifestation of EI virus infection in mature horses. All horses may develop secondary bacterial bronchopneumonia, with mature horses more likely to die. EI outbreaks among heavily pregnant mares can result in increased neonatal losses because of premature placental separation and dystocia causing fetal hypoxia.
McKenzie HC, Murray MJ.To compare concentrations of gentamicin in serum and bronchial lavage fluid after IV and aerosol administration of gentamicin to horses. Methods: 9 healthy adult horses. Methods: Gentamicin was administered by aerosolization (20 ml of gentamicin solution [50 mg/ml]) and IV injection (6.6 mg of gentamicin/kg of body weight) to each horse, with a minimum of 2 weeks between treatments. Samples of pulmonary epithelial lining fluid were collected by small volume (30 ml) bronchial lavage 0.5, 4, 8, and 24 hours after gentamicin administration. Serum samples were obtained at the same times. All sampl...
Clarke DL.Chondromalacia of the tracheal and bronchial cartilages and redundancy of the dorsal tracheal membrane result in collapse of the large airways, leading to coughing and airway obstruction. It most commonly affects small-breed dogs, although larger-breed dogs, cats, and miniature horses are also sporadically reported. Dynamic airway imaging is used to confirm the diagnosis. The primary goal of medical management is to control clinical signs attributable to coughing and airway inflammation. When this is no longer effective, tracheal stents provide a minimally invasive, rapid way to restore airway...
McGorum BC, Dixon PM.Local transendoscopic endobronchial antigen challenge, which has proved to be a valuable clinical and research technique in the study of human pulmonary hypersensitivity, was evaluated in control and asymptomatic COPD--affected horses. Transendoscopic endobronchial challenges with phosphate-buffered saline (PBS), Micropolyspora faeni extract at 60 and 600 micrograms/ml and mouldy hay extract elicited neutrophilic airway inflammatory responses in control (N = 5-7) and asymptomatic COPD-affected (N = 5-7) horses, as determined by cytological examinations of bronchoalveolar lavage fluid (BALF) ha...
O'Callaghan MW, Pascoe JR, Tyler WS, Mason DK.Lungs from 19 Thoroughbred racehorses with a history of exercise-induced pulmonary haemorrhage (EIPH) were studied using several forms of microscopy. Light microscopy of paraffin sections revealed three lesions in the caudodorsal region of the lungs from each horse. These correspond with the location of blue to brown stains seen at necropsy. These lesions include sequelae of bronchiolitis, hemosiderophages and increased connective tissue. Much of each of the lungs appeared normal, especially the more cranial or ventral portions. Foci of eosinophil infiltration were found in seven of the 19 lun...
Issouf M, Vargas A, Boivin R, Lavoie JP.Smooth muscle has a central role in bronchospasm-induced airway obstruction in asthma. Alternative mRNA splicing of the smooth muscle myosin heavy chain (myh11) gene produces four different isoforms, one of which (SMB) is characterized by the inclusion of the exon5b, which doubles the smooth muscle cells contraction velocity. Deciphering the regulation of the expression levels of the SMB isoform would represent a major step for the understanding of the triggers and pathways leading to airway smooth muscle contraction in asthma. Our objective was therefore, to study the splicing regulation mech...
Dixon CE, Bedenice D, Mazan MR.Airway hyperresponsiveness (AHR) is linked to airway inflammation and is considered a key manifestation of mild/moderate equine asthma (EA). The study purpose was to determine whether two modalities of non-invasive lung function testing (FOM-forced oscillatory mechanics vs. FP-flowmetric plethysmography) establish the same clinical diagnosis of AHR in horses, using histamine bronchoprovocation. Nineteen horses (3-25 years, 335-650 kg) with clinical signs suggestive of mild/moderate equine asthma were enrolled. FOM and FP testing was performed in each horse on two consecutive days, using a rand...
Robinson NE, Sorenson PR.Obstruction of the upper and lower airways is common in horses. In the upper airway, paresis of abductor muscles of the nares and larynx allows inspiratory collapse of soft tissues, which is accentuated by factors increasing upper airway resistance and by high inspiratory flow rates. Intrapulmonary airway obstruction occurs due to accumulation of secretions, release of chemical mediators in response to a variety of stimuli, and parasympathetic stimulation of airways. Obstruction of large airways increases the work of breathing, whereas obstruction of small airways may cause no measurable incre...
Bartner LR, Robinson NE, Kiupel M, Tesfaigzi Y.This study examined the contribution of delayed apoptosis of bronchial mucous cells to mucus accumulation in equine recurrent airway obstruction (RAO). In pilot studies, Bcl-2, an apoptosis inhibitor, was detected in airway mucous cells of RAO-affected horses in remission and during acute disease, when most mucus was secreted. To study whether delayed apoptosis results in an increase in the number of mucous cells during disease recovery, six RAO-affected and six control horses were fed hay for 5 days to induce inflammation and then pellets for 7 days to partially resolve RAO before euthanasia....
van Nieuwstadt RA, Henricks PA, Hajer R, van der Meer van Roomen WA, Breukink HJ, Nijkamp FP.This study was undertaken to assess the importance of muscarinic receptor subtypes in equine airway disease. Smooth muscle strips from the mid-cervical portion of the trachea of horses were placed in tissue baths and isometric contractile force was measured. Active force was measured in response to metacholine and the selective muscarinic receptor agonists McN-A-343 (M1-selective) and pilocarpine (M2-selective) in cumulative concentrations (10(-9)M through 10(-3)M), with and without preincubation with three or four concentrations of the selective muscarinic receptor antagonists pirenzepine (M1...
van den Hoven R, Zappe H, Zitterl-Eglseer K, Jugl M, Franz C.The effects of an oral preparation containing an extract of thyme and primula (Bronchipret; Bionorica) on the lung function of five horses suffering heaves were determined in a longitudinal study. The horses accepted the product well. The plasma concentrations of the marker substance, thymol, indicated that at least one of the substances in the extract had been absorbed from the gastrointestinal tract. The compliance, pulmonary pressure and airway resistance of the horses' lungs were all significantly improved after one month of treatment However, the severity of their clinical signs and their...
Ter Woort F, Caswell JL, Arroyo LG, Viel L.OBJECTIVE To describe histologic findings in the small airways during postmortem examination of actively racing horses and to quantify the degree of airway inflammation by use of a semiquantitative scoring system. SAMPLE Lung tissues obtained from 95 horses (Thoroughbreds, Standardbreds, and Quarter Horses) that had been actively racing or training. PROCEDURES 10 standardized lung sections were obtained during postmortem examination of 37 horses that had been actively racing or training, and 2 histologic sections of the caudodorsal lung lobes previously collected from each of 58 horses that di...
Cunningham FM, Dunkel B.Recurrent airway obstruction (RAO) and insect bite hypersensitivity (IBH) are allergic conditions that are commonly encountered in the horse. Whilst complete allergen avoidance is an effective management strategy for both diseases, this may not be achievable in all cases and treatment options are therefore required. The inflammatory response is the main therapeutic target for glucocorticoids given to horses with RAO and severe cases of IBH, whilst the bronchodilators used in RAO primarily target airway smooth muscle. Such drugs are effective in most but not all individuals and there may be unw...
Oikawa M.The dorsocaudal extremities of the caudal lobes of the lungs of racehorses are vulnerable to exercise-induced pulmonary haemorrhage (EIPH). The morphology of the lungs at these sites was studied in 13 Thoroughbred horses aged 18 to 22 months. These animals, which had been performing low-intensity exercise on a track at maximum running speeds of approximately 5-8.5 metres/second (m/s), were withdrawn from the racehorse training programme for reasons of unsuitability. Lung lesions observed in the dorsocaudal lung extremities in 10 of the 13 horses were not found in the craniodorsal or craniovent...
