Lung health in horses encompasses the study of respiratory system function, disease, and maintenance in equine species. The equine respiratory system is vital for oxygen exchange and plays a significant role in overall health and athletic performance. Conditions affecting lung health include inflammatory airway disease (IAD), recurrent airway obstruction (RAO), and exercise-induced pulmonary hemorrhage (EIPH). These conditions can impact a horse's respiratory efficiency and performance capabilities. Research in this area often focuses on understanding the pathophysiology, diagnosis, and management of respiratory diseases, as well as the impact of environmental factors on lung function. This page compiles peer-reviewed research studies and scholarly articles that explore the mechanisms, diagnostic approaches, and therapeutic strategies related to lung health in horses.
Boivin R, Vargas A, Cano P, Lavoie JP.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...
Ida KK, Sauvage A, Gougnard A, Grauwels M, Serteyn D, Sandersen C.Ponies with tracheal collapse may have an increased anesthetic risk due to airway obstruction during induction and recovery. To our knowledge, there are no anesthetic descriptions of these patients, despite a reported 5.6% incidence and 77% mortality rate. Two Shetland ponies with tracheal collapse, a 12-year-old male (pony 1) and a 27-year-old female (pony 2), were referred for right eye enucleation due to a perforating corneal ulcer and severe recurrent uveitis, respectively. Pony 1 was stressed, had lung stridor and hyperthermia, and developed inspiratory dyspnea with handling. Radiography ...
Barton AK, Schulze T, Doherr MG, Gehlen H.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...
Bowser JE, Costa LRR, Rodil AU, Lopp CT, Johnson ME, Wills RW, Swiderski CE.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...
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...
Rosenberg HF, Druey KM.Asthma is a chronic, heterogeneous, and recurring inflammatory disease of the lower airways, with exacerbations that feature airway inflammation and bronchial hyperresponsiveness. Asthma has been modeled extensively via disease induction in both wild-type and genetically manipulated laboratory mice (Mus musculus). Antigen sensitization and challenge strategies have reproduced numerous important features of airway inflammation characteristic of human asthma, notably the critical roles of type 2 T helper cell cytokines. Recent models of disease induction have advanced to include physiologic aero...
Huber L, Giguère S, Berghaus LJ, Hanafi A, Vitosh-Sillman S, Czerwinski SL.Rhodococcus equi is one of the most important causes of disease in foals. Infection is typically characterized by pyogranulomatous pneumonia although extrapulmonary infections occur occasionally. Uveitis and polysynovitis have been reported in foals naturally infected with R. equi and are thought to be the result of an immune-mediated process. However, the pathogenesis of these conditions is poorly understood. The objectives of this study were to document the occurrence of uveitis and polysynovitis after experimental infection with R. equi and to determine if these disorders are the direct res...
Bullone M, Joubert P, Gagné A, Lavoie JP, Hélie P.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...
Anderson SL, Singh B.Horses are susceptible to a multitude of inflammatory conditions that are characterized by a strong neutrophilic response. Here, we review basic equine neutrophil biology and explore the role of neutrophils in inflammatory conditions with emphasis on intestinal ischemia and reperfusion injury and lung inflammation. In addition, unique aspects of equine neutrophil biology have been highlighted. Neutrophils comprise the highest proportion of circulating white blood cells in equine blood. The concentration of circulating equine neutrophils is a primary indicator of systemic inflammation. Addition...
Mosing M, Senior JM.In the first edition of this journal, Barbara Weaver wrote a review titled 'Equine Anaesthesia', stating that, at that time, it was quickly becoming accepted practice that many horses were being anaesthetised 'by essentially similar procedures, i.e. premedication, induction and then maintenance by controlled inhalation'. To celebrate the 50th anniversary of the first edition of this journal, this review covers the development of understanding and practice of inhalational anaesthesia and controlled ventilation in horses over the last 50 years. We review how the perceived benefits of halothane ...
Berlin S, Wallstabe S, Scheuch E, Oswald S, Hasan M, Wegner D, Grube M, Venner M, Ullrich A, Siegmund W.Standard treatment of foals with severe abscessing lung infection caused by Rhodococcus equi using rifampicin and a macrolide antibiotic can be compromised by extensive inhibition and/or induction of drug metabolising enzymes (e.g. CYP3A4) and transport proteins (e.g. P-glycoprotein), as has been shown for rifampicin and clarithromycin. The combination of rifampicin with the new, poorly metabolised gamithromycin, a long-acting analogue of azithromycin and tulathromycin with lower pharmacokinetic interaction potential, might be a suitable alternative. Objective: To evaluate the pharmacokinetic ...
Schneberger D, Sethi RS, Singh B.Endothelium plays an important role in maintaining the vascular barrier and physiological homeostasis. Endothelium also is fundamental to the initiation and regulation of inflammation. Endothelium demonstrates phenotypic and functional heterogeneity not only among various organs but also within an organ. One of the striking examples would be the pulmonary endothelium that participates in creating blood-air barrier. Endothelium in large pulmonary blood vessels is distinct in structure and function from that lining of the pulmonary capillaries. This chapter focuses on the comparative aspects of ...
Ferrari CR, Cooley J, Mujahid N, Costa LR, Wills RW, Johnson ME, Swiderski CE.Severe equine asthma, formerly recurrent airway obstruction (RAO), is the horse counterpart of human asthma, affecting horses maintained indoors in continental climates. Equine pasture asthma, formerly summer pasture RAO, is clinically similar but affects grazing horses during hot, humid conditions in the southeastern United States and United Kingdom. To advance translational relevance of equine pasture asthma to human asthma, histologic features of airway remodeling in human asthma were scored in lung lobes from 15 pasture asthma-affected and 9 control horses of mixed breeds. All noncartilagi...
Vargas A, Boivin R, Cano P, Murcia Y, Bazin I, Lavoie JP.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...
Lee Y, Kiupel M, Soboll Hussey G.Dendritic cells (DCs) are professional antigen-presenting cells that have multiple subpopulations with different phenotypes and immune functions. Previous research demonstrated that DCs have strong potential for anti-viral defense in the host. However, viruses including alphaherpesvirinae have developed strategies to interfere with the function or maturation of DCs, causing immune dysfunction and avoidance of pathogen elimination. The goal of the present study was to isolate and characterize equine lung-derived DCs (L-DCs) for use in studies of respiratory viruses and compare their features wi...
Echeverria KO, Lascola KM, Giguère S, Foreman JH, Austin SA.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 ...
Rossi HS, Koho NM, Ilves M, Rajamäki MM, Mykkänen AK.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...
Bond SL, Timsit E, Workentine M, Alexander T, Léguillette R.The microbial composition of the equine respiratory tract, and differences due to mild equine asthma (also called Inflammatory Airway Disease (IAD)) have not been reported. The primary treatment for control of IAD in horses are corticosteroids. The objectives were to characterize the upper and lower respiratory tract microbiota associated with respiratory health and IAD, and to investigate the effects of dexamethasone on these bacterial communities using high throughput sequencing. Results: The respiratory microbiota of horses was dominated by four major phyla, Proteobacteria (43.85%), Actinob...
Bullone M, Vargas A, Elce Y, Martin JG, Lavoie JP.Asthmatic airways are inflamed and undergo remodelling. Inhaled corticosteroids and long-acting β2-agonist combinations are more effective than inhaled corticosteroid monotherapy in controlling disease exacerbations, but their effect on airway remodelling and inflammation remains ill-defined. This study evaluates the contribution of inhaled fluticasone and salmeterol, alone or combined, to the reversal of bronchial remodelling and inflammation. Severely asthmatic horses (6 horses/group) were treated with fluticasone, salmeterol, fluticasone/salmeterol, or with antigen avoidance for 12 weeks. ...
Bullone M, Pouyet M, Lavoie JP.Peripheral airway smooth muscle (ASM) mass is increased in severe equine asthma, but no information is available on age related changes in ASM. In this study, peripheral ASM dimensions were determined in healthy horses of different ages. The thickness of the peripheral ASM layer was constant in horses of different ages, but ASM occupied a greater proportion of the inner wall area in young horses compared to older horses. This finding suggests that equine airways experience a decrease in the relative abundance of ASM with age.
Large multicenter clinical trials have led to two recently approved drugs for patients with idiopathic pulmonary fibrosis (IPF); yet, both of these therapies only slow disease progression and do not provide a definitive cure. Traditionally, preclinical trials have utilized mouse models of bleomycin (BLM)-induced pulmonary fibrosis-though several limitations prevent direct translation to human IPF. Spontaneous pulmonary fibrosis occurs in other animal species, including dogs, horses, donkeys, and cats. While the fibrotic lungs of these animals share many characteristics with lungs of patients w...
Mosing M, Auer U, MacFarlane P, Bardell D, Schramel JP, Böhm SH, Bettschart-Wolfensberger R, Waldmann AD.The aim of this study was to evaluate the effect of continuous positive airway pressure (CPAP) on regional distribution of ventilation and dead space in anaesthetized horses. Methods: Randomized, experimental, crossover study. Methods: A total of eight healthy adult horses. Methods: Horses were anaesthetized twice with isoflurane in 50% oxygen and medetomidine as continuous infusion in dorsal recumbency, and administered in random order either CPAP (8 cmHO) or NO CPAP for 3 hours. Electrical impedance tomography (and volumetric capnography (VCap) measurements were performed every 30 minutes. L...
Léguillette R, Tohver T, Bond SL, Nicol JA, McDonald KJ.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...
Calzetta L, Roncada P, di Cave D, Bonizzi L, Urbani A, Pistocchini E, Rogliani P, Matera MG.Equine asthma is a disease characterised by reversible airflow obstruction, bronchial hyper-responsiveness and airway inflammation following exposure of susceptible horses to specific airborne agents. Although clinical remission can be achieved in a low-airborne dust environment, repeated exacerbations may lead to irreversible airway remodelling. The available data on the pharmacotherapy of equine asthma result from several small studies, and no head-to-head clinical trials have been conducted among the available medications. Objective: To assess the impact of the pharmacological interventions...
Partlow J, David F, Hunt LM, Relave F, Blond L, Pinilla M, Lavoie JP.Small volume pneumothorax can be challenging to diagnose in horses. The current standard method for diagnosis is standing thoracic radiography. We hypothesized that thoracic ultrasonography would be more sensitive. Objectives of this prospective, experimental study were to describe a thoracic ultrasound method for detection of small volume pneumothorax in horses and to compare results of radiography and ultrasound in a sample of horses with induced small volume pneumothorax. Six mature healthy horses were recruited for this study. For each horse, five 50 ml air boluses were sequentially introd...
Vargas A, Peltier A, Dubé J, Lefebvre-Lavoie J, Moulin V, Goulet F, Lavoie JP.OBJECTIVE To develop a method to maintain the initial phenotype of airway smooth muscle (ASM) cells isolated from equine endobronchial biopsy specimens in long-term cell culture. SAMPLE Endobronchial tissue specimens (8 to 10/horse) collected from the lungs of previously healthy horses at necropsy (n = 12) and endobronchial biopsy specimens collected from standing, sedated, heaves-affected horses in clinical remission of the disease (5) and control horses (4). PROCEDURES A sampling protocol was developed to recover and maintain a contractile phenotype in ASM cells from endobronchial specimens ...
Berlin S, Kirschbaum A, Spieckermann L, Oswald S, Keiser M, Grube M, Venner M, Siegmund W.The treatment of equine lung infections by Rhodococcus equi with rifampicin is empirically based because pharmacokinetic/pharmacodynamic (PK/PD) indices and pivotal clinical outcome data are not available. Objective: To evaluate the pharmacokinetics and pulmonary distribution of rifampicin into epithelial lining fluid (ELF) and bronchoalveolar lavage cells (BALC) to predict antimicrobial activity in the lung using PK/PD indices. Methods: Controlled, randomised, two-period, crossover, repeated-dose study with an initial arm to measure disposition after i.v. administration of rifampicin. Methods...
Mosing M, Marly-Voquer C, MacFarlane P, Bardell D, Böhm SH, Bettschart-Wolfensberger R, Waldmann AD.To evaluate the regional distribution of ventilation in horses during spontaneous breathing and controlled mechanical ventilation (CMV) using electrical impedance tomography (EIT). Methods: Prospective, experimental case series. Methods: Four anaesthetized experimental horses. Methods: Horses were anaesthetized with isoflurane in an oxygen-air mixture and medetomidine continuous rate infusion, placed in dorsal recumbency with an EIT belt around the thorax, and allowed to breathe spontaneously until PaCO reached 13.3 kPa (100 mmHg), when volume CMV was started. For each horse, the EIT signal wa...
Jacobson GA, Raidal S, Robson K, Narkowicz CK, Nichols DS, Haydn Walters E.Salbutamol is usually administered as a racemic mixture but little is known about the enantioselectivity of salbutamol pharmacokinetics in the lung. This study was designed to investigate enantiomer concentrations in lung tissue after inhaled dosing. Horses (n = 12) received racemic salbutamol 1000 μg via inhalation. Enantioselective ultra performance liquid chromatography-tandem mass spectrometry was used to determine salbutamol concentrations in pulmonary epithelial lining fluid (PELF) sampled 2, 5, 10 and 15 min after administration, in central lung (endoscopic bronchial biopsy) and per...
Calzetta L, Roncada P, di Cave D, Bonizzi L, Urbani A, Pistocchini E, Rogliani P, Matera MG.Equine asthma is a disease characterised by reversible airflow obstruction, bronchial hyper-responsiveness and airway inflammation following exposure of susceptible horses to specific airborne agents. Although clinical remission can be achieved in a low-airborne dust environment, repeated exacerbations may lead to irreversible airway remodelling. The available data on the pharmacotherapy of equine asthma result from several small studies, and no head-to-head clinical trials have been conducted among the available medications. Objective: To assess the impact of the pharmacological interventions...
Ambrisko TD, Schramel J, Hopster K, Kästner S, Moens Y.To examine changes in the distribution of ventilation and regional lung compliances in anaesthetized horses during the alveolar recruitment manoeuvre (ARM). Methods: Experimental study in which a series of treatments were administered in a fixed order on one occasion. Methods: Five adult Warmblood horses. Methods: Animals were anaesthetized (xylazine, midazolam-ketamine, isoflurane), placed in dorsal recumbency and ventilated with 100% oxygen using peak inspiratory pressure (PIP) and positive end-expiratory pressure (PEEP) of 20 cmHO and 0 cmHO, respectively. Thoracic electrical impedance tomo...
Pirie RS, Dixon PM, McGorum BC.Mould extract inhalation challenges have been used extensively in the investigation of heaves. Such challenges have induced pulmonary neutrophilic inflammation and dysfunction, consistent with, but less severe than the natural disease. However, the method of mould extract production is likely to result in endotoxin contamination. Objective: To investigate whether insufficient dose delivery was responsible for the shortfall in response to inhaled extract compared with natural disease, and whether endotoxin contamination of mould extract contributed to the pulmonary inflammation and dysfunction....
Bullone M, de Lagarde M, Vargas A, Lavoie JP.The identification of serum biomarkers of lung inflammation would facilitate the diagnosis of inflammatory airway disease (IAD) in horses. Objective: Horses with IAD have higher serum concentrations of markers of inflammation compared to controls. Methods: Twelve horses with IAD and 10 control horses. Methods: This was a prospective case-control study. Blood and BALF were collected from horses with IAD and controls. Serum concentration of surfactant protein D (SP-D), haptoglobin, serum amyloid A (SAA) and of the soluble form of triggering receptor expressed on myeloid cells 1 (sTREM-1) was mea...
Morley PS, Bromberek JL, Saulez MN, Hinchcliff KW, Guthrie AJ.Exercise-induced pulmonary haemorrhage (EIPH) occurs commonly in Thoroughbred racehorses worldwide. While EIPH is believed to be an important cause of impaired performance in these horses, there is limited evidence from sufficiently powered studies to evaluate this association. Objective: To evaluate whether EIPH is associated with finishing position, distance finished behind race winners and differences in race earning among Thoroughbred horses racing in South Africa. Methods: Prospective cross-sectional study. Methods: One thousand Thoroughbred horses racing in South Africa were enrolled pri...
Ambrisko TD, Schramel JP, Adler A, Kutasi O, Makra Z, Moens YP.The aim was to evaluate the feasibility of using electrical impedance tomography (EIT) in horses. Thoracic EIT was used in nine horses. Thoracic and abdominal circumference changes were also measured with respiratory ultrasound plethysmography (RUP). Data were recorded during baseline, rebreathing of CO2 and sedation. Three breaths were selected for analysis from each recording. During baseline breathing, horses regularly took single large breaths (sighs), which were also analysed. Functional EIT images were created using standard deviations (SD) of pixel signals and correlation coefficients (...
Hansen S, Otten ND, Birch K, Skovgaard K, Hopster-Iversen C, Fjeldborg J.The pathophysiology of equine asthma (EA) is still not fully described, but the involvement of an allergic reaction is strongly suspected. This theory has led to the use of allergen-specific immunoglobulin (Ig)E tests to support a diagnosis of asthma. The objective of this descriptive study was to evaluate the correlation between four subgroups of EA (mastocytic mild equine asthma [MEA], neutrophilic MEA, mixed MEA, and severe equine asthma [SEA]), allergen specific IgE (measured in both serum and BALF) and mRNA expression of selected genes in bronchoalveolar lavage fluid (BALF). Serum and BAL...
Katavolos P, Ackerley CA, Clark ME, Bienzle D.Horses suffer from recurrent airway obstruction, an asthma-like condition induced by repeat inhalation of environmental substances present in barn air. Clara cell secretory protein (CCSP) is much reduced during active inflammation when neutrophils predominate in the airways, and in chronic asthmatics. We sought to investigate morphologic and functional interactions of CCSP with neutrophils. Bronchoalveolar and blood neutrophils from healthy control animals, and from animals with recurrent airway obstruction in remission and exacerbation, were evaluated by immuno-cytochemistry and immuno-electr...
Abraham G, Kottke C, Dhein S, Ungemach FR.Although in the respiratory system there is great therapeutic interest in manipulating and understanding the beta-adrenoceptor-G-protein-adenylate cyclase (AC) signal transduction pathway, little is known on segmental differences among lung, bronchus, and trachea with regard to the receptor concentration and interaction to G-proteins and coupling to AC. In this study, patterns of distribution and absolute quantities of beta-adrenoceptor subtypes beta(1) and beta(2) were determined in membranes of equine lung parenchyma, bronchial and tracheal epithelium with the underlying smooth muscle by sat...
Côté O, Lillie BN, Hayes MA, Clark ME, van den Bosch L, Katavolos P, Viel L, Bienzle D.Secretoglobin 1A1 (SCGB 1A1), also called Clara cell secretory protein, is the most abundantly secreted protein of the airway. The SCGB1A1 gene has been characterized in mammals as a single copy in the genome. However, analysis of the equine genome suggested that horses might have multiple SCGB1A1 gene copies. Non-ciliated lung epithelial cells produce SCGB 1A1 during inhalation of noxious substances to counter airway inflammation. Airway fluid and lung tissue of horses with recurrent airway obstruction (RAO), a chronic inflammatory lung disease affecting mature horses similar to environmental...
Marenzoni ML, Passamonti F, Lepri E, Cercone M, Capomaccio S, Cappelli K, Felicetti M, Coppola G, Coletti M, Thiry E.A 15-year-old Belgian gelding was referred for fever, depression, and respiratory distress. Lung biopsy revealed interstitial fibrosis consistent with chronic interstitial pneumonia. Equid herpesvirus 5 (EHV-5) DNA was detected by polymerase chain reaction (PCR) in bronchoalveolar lavage and biopsy specimens. A presumptive diagnosis of equine multinodular pulmonary fibrosis (EMPF) was made, and the horse was administered a systemic treatment with corticosteroids and antiviral drugs. Despite initial clinical improvement, 4 weeks later, the condition of the horse rapidly deteriorated, and the an...
Eyre P, Lewis AJ.1. Histamine in small doses caused systemic depressor responses in horses, whereas greater doses caused biphasic effects. All doses of 5-hydroxytrypt-amine (5-HT) were pressor and all doses of bradykinin depressor. All three active substances raised pulmonary artery pressure and lowered central venous pressure. 5-HT reduced ventilation volume. Histamine caused brief apnoea followed by hyperpnoea only.2. Acute anaphylaxis in the horse was accompanied by a severe systemic arterial depressor response, a pressor response in the pulmonary artery and vena cava, and alternating phases of apnoea and d...
Simões J, Sales Luís J, Tilley P.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...
Lavoie JP, Leclere M, Rodrigues N, Lemos KR, Bourzac C, Lefebvre-Lavoie J, Beauchamp G, Albrecht B.Corticosteroids are the most potent drugs for the control of severe equine asthma, but adverse effects limit their chronic systemic administration. Inhaled medications allow for drug delivery directly into the airways, reducing the harmful effects of these drugs. Objective: To evaluate the efficacy of inhaled budesonide specifically formulated for the equine use and administered by a novel inhalation device in horses with severe asthma. Methods: Experimental studies in horses with naturally occurring asthma with cross-over, randomised, blinded experimental designs. Methods: In Study 1, budeson...
Yoshikawa H, Yasu T, Ueki H, Oyamada T, Oishi H, Anzai T, Oikawa M, Yoshikawa T.To evaluate the possibility that Streptococcus equi subsp. zooepidemicus (S.z) the causative bacterial agent of equine shipping fever pneumonia (ESFP), as well as to investigate its pathogenesis, 10 horses (seven Thoroughbreds and three Anglo-Arab species, ranging from 2-4 years in age) were experimentally inoculated, via an endoscope, into bronchus of the lung lobe with a dose of 30 ml of 1-7 x 10(8) CFU/ml of S.z. After inoculation, autopsy and pathological examinations were sequentially conducted 30 min, 1, 2, 3, 4, 17, 20 hr and 2 weeks later. Pneumonia induced by the intrapulmonary inocul...
Lavoie JP, Pasloske K, Joubert P, Cordeau ME, Mancini J, Girard Y, Friesen RW, Frenette R, Blouin M, Young RN, Hickey G.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 ...
de Lagarde M, Rodrigues N, Chevigny M, Beauchamp G, Albrecht B, Lavoie JP.Bronchospasm results in airway obstruction in horses with heaves. Atropine is the most potent bronchodilator drug currently available for horses, but is associated with side effects that limit its use. Like atropine, N-butylscopolammonium bromide (NBB) is an anticholinergic agent with bronchodilatory properties. Objective: To compare the bronchodilating effects and side effects of atropine and NBB in horses with heaves. Methods: Cross-over experiment using horses with heaves. Methods: Eight horses with heaves were administered atropine and NBB, using a cross-over design. Heart rate, pupillary ...
Hooper-McGrevy KE, Giguere S, Wilkie BN, Prescott JF.To determine whether purified equine immunoglobulin specific for Rhodococcus equi virulence-associated proteins A and C (VapA and VapC) can confer passive protection against R. equi-induced pneumonia in foals. Methods: Twenty-eight 3-week-old mixed-breed pony foals. Methods: 7 foals received IV injections of equine hyperimmune plasma (HIP) against whole-cell R. equi, and 7 received purified equine immunoglobulin specific for VapA and VapC 1 day prior to intrabronchial infection with R. equi strain 103+. Eleven foals were not treated prior to infection, and 3 control foals were neither treated ...
Stadler P, Deegen E.Dynamic compliance, airway resistance, viscous work and respiratory frequency were measured at intervals in horses over 12 h periods. Variation, daily averages and circadian patterns were recorded. Examinations were performed on 24 horses. They were divided into three groups: Normal horses, horses with chronic latent bronchitis and horses with manifest chronic obstructive pulmonary disease (COPD). Significant differences were found between the daily averages and the fluctuations when the normal group and the COPD group were compared. In most cases differences between all three groups were sign...
Mazan MR, Vin R, Hoffman AM.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...
Arens AM, Barr B, Puchalski SM, Poppenga R, Kulin RM, Anderson J, Stover SM.California horses incur a bone fragility syndrome manifested by pathologic fractures. This study investigated gross, radiographic, and histologic features of the disorder as well as relationships with silicosis and levels of heavy metals and trace minerals through a postmortem study of 9 affected and 3 unaffected horses. Bones and soft tissues were evaluated grossly and histologically. Bones, lymph nodes, and lung tissue were evaluated radiographically. Tissues were evaluated for silicon levels, intracytoplasmic crystals, heavy metals, and trace minerals. All 9 affected horses had osteoporosis...
Mosing M, Marly-Voquer C, MacFarlane P, Bardell D, Böhm SH, Bettschart-Wolfensberger R, Waldmann AD.To evaluate the regional distribution of ventilation in horses during spontaneous breathing and controlled mechanical ventilation (CMV) using electrical impedance tomography (EIT). Methods: Prospective, experimental case series. Methods: Four anaesthetized experimental horses. Methods: Horses were anaesthetized with isoflurane in an oxygen-air mixture and medetomidine continuous rate infusion, placed in dorsal recumbency with an EIT belt around the thorax, and allowed to breathe spontaneously until PaCO reached 13.3 kPa (100 mmHg), when volume CMV was started. For each horse, the EIT signal wa...
Couëtil LL, Art T, de Moffarts B, Becker M, Mélotte D, Jaspar F, Bureau F, Lekeux P.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...
Moore EH, Shelton DK, Wisner ER, Richardson ML, Bishop DM, Brock JM.To reexamine the blood patch technique in a laboratory model of lung biopsy free of confounding clinical variables. Methods: An equine model of lung biopsy was developed with an excised lobe connected to an insufflation bulb and pressure monitor. Patched and control unpatched punctures were made in the lung surface, and the pressure within the lung was raised to the maximum achievable. Whether air leakage from the puncture sites could be induced was determined and, if so, at what pressure it occurred. Results: At statistical analysis with the Kaplan-Meier test and the Cox proportional hazards ...
McGorum BC, Dixon PM, Halliwell RE, Irving P.A comparison was made of the cellular and molecular components of bronchoalveolar lavage fluid (BALF) harvested from the left and right diaphragmatic lobes, the accessory lobe of the right lung and the apical lobe of the left lung, of seven control horses and six horses with symptomatic chronic obstructive pulmonary disease (COPD). Neither control nor symptomatic COPD affected horses showed significant regional differences in BALF recovery volumes, total and differential BALF cell counts, albumen adjusted total and absolute BALF cell counts, total and absolute pulmonary epithelial lining fluid...
Derksen FJ, Robinson NE.Pleural and esophageal pressures were compared in 6 standing sedated ponies. Pleural pressure was measured with blunt needles attached to transducers and inserted in the 10th intercostal space level with and 10 and 20 cm above the point of the shoulder. Two balloons (a condom and an esophageal balloon) attached to transducers measured esophageal pressure in the cranial, middle, and caudal portions of the thoracic part of the esophagus. Tidal volume was measured by integrating a flow signal derived from a pneumotachograph attached to an endotracheal tube inserted through a tracheostomy. Frequen...
Miskovic M, Couëtil LL, Thompson CA.The effects of long-term environmental management on airway obstruction and inflammation in horses with recurrent airway obstruction (RAO) are unknown. Objective: Horses with RAO maintained in low-dust environments have persistent airway obstruction and neutrophilic inflammation. Methods: Study horses were treated for RAO and then maintained in low-dust environments with no medical management. Horses were classified into 3 groups by years after diagnosis: 1 year (time 1, n = 9), 2-3 years (time 2, n = 7), and 5-6 years (time 3, n = 8). The comparison groups were age-matched healthy horses. Met...
Sacks M, Byrne DP, Herteman N, Secombe C, Adler A, Hosgood G, Raisis AL, Mosing M.Left-sided cardiac volume overload (LCVO) can cause fluid accumulation in lung tissue changing the distribution of ventilation, which can be evaluated by electrical impedance tomography (EIT). Objective: To describe and compare EIT variables in horses with naturally occurring compensated and decompensated LCVO and compare them to a healthy cohort. Methods: Fourteen adult horses, including university teaching horses and clinical cases (healthy: 8; LCVO: 4 compensated, 2 decompensated). Methods: In this prospective cohort study, EIT was used in standing, unsedated horses and analyzed for convent...
van Erck E, Votion DM, Kirschvink N, Art T, Lekeux P.To compare sensitivity of the impulse oscillometry system (IOS) with that of the conventional reference technique (CRT; ie, esophageal balloon method) for pulmonary function testing in horses. Methods: 10 horses (4 healthy; 6 with recurrent airway obstruction [heaves] in remission). Methods: Healthy horses (group-A horses) and heaves-affected horses (group-B horses) were housed in a controlled environment. At each step of a methacholine bronchoprovocation test, threshold concentration (TC(2SD); results in a 2-fold increase in SD of a value) and sensitivity index (SI) were determined for respir...
Ambrósio AM, Ida KK, Souto MT, Oshiro AH, Fantoni DT.To assess if positive end-expiratory pressure (PEEP) titration improves gas exchange and respiratory mechanics, without hemodynamic impairment in horses during anesthesia. Methods: Prospective, randomized study. Methods: Thirteen isoflurane-anesthetized healthy horses. Methods: After 60 minutes of anesthesia with spontaneous breathing, mechanical ventilation was initiated with an inspiratory-expiratory ratio of 1:2, PEEP of 5 cmH2O, tidal volume of 10-20 mL kg(-1) and respiratory rate adjusted to maintain normocapnia. Constant PEEP of 5 cmH2O was continued (control group; n = 6) or titrated (P...
