Search

Simple Summary: Equine asthma is a common pulmonary disorder among equine patients. Up to seventy percent of young sports horses are affected, although they do not show clinical signs like coughing. The diagnosis of equine asthma in these horses is challenging but important, as mild-to-moderate equine asthma may deteriorate with time. This review summarizes options to diagnose equine asthma early in the disease process and discusses possible difficulties. Interestingly, stressing the airways using exercise or cold air may help to identify horses suffering from mild disease or severe equine asthma in remission. This literature review focuses on diagnostics of equine asthma (EA), possible influencing factors on diagnostic techniques and latest developments in diagnosing horses during EA remission or with subclinical disease. Routine EA diagnostics include a clinical examination of the respiratory system with percussion and auscultation including a rebreathing examination, and clinical pathology including white blood cells and arterial blood gas analysis. Subsequent diagnostics include bronchoscopy to evaluate the amount and viscosity of respiratory secretion, bronchoalveolar lavage, and the cytology of tracheal aspirates (TAs) and bronchoalveolar lavage fluid (BALF). The grading of EA severity is built on respiratory effort at rest, which is increased in severe equine asthma. The inflammatory subtype is based on BALF cytology, while TA cytology helps to rule out previous bacterial infections. Different factors have an impact on the airways regarding the structure of the epithelium, cytology, and inflammatory markers possibly influencing the diagnosis of EA. Short-term exercise increases the total cell count and inflammatory mediators identified in the BALF of human patients, asymptomatic horses, and other species. Other factors involve cold or chlorinated air, long-term training effects, and concurrent additional respiratory disease, in particular exercise-induced pulmonary hemorrhage. As BALF cytology may be unremarkable during EA remission and low-grade disease, exercise tests and other factors stressing the bronchial epithelium may help to diagnose these patients. [ABSTRACT FROM AUTHOR]

Simple Summary: Equine asthma is a common inflammatory disease that decreases athletic ability, and in its severe form, negatively impacts the welfare of horses. Although genetics and environmental antigenic exposure are the main triggers of the disease, other physiological factors could influence its occurrence and severity. In humans, vitamin D deficiency is a risk factor for the development of asthma, possibly via modulation of the immune system by this micronutrient. Therefore, we aimed to determine whether vitamin D levels differ in horses affected by mild–moderate asthma, severe asthma, and healthy control horses. We observed that serum vitamin D levels were similar in all three groups, but that several physiological parameters were associated with its concentration. Vitamin D deficiency is associated with asthma development and severity of symptoms in humans, but whether the same occurs in horses is unknown. We aimed to determine whether the serum vitamin D levels differ in horses with asthma compared to control animals and, secondarily, to explore clinical, respiratory, and environmental parameters associated with its concentration in equids in a retrospective cross-sectional study. The total serum vitamin D (25(OH)D) was measured by radioimmunoassay in 45 serum samples from the Equine Respiratory Tissue Biobank (15 control animals, 14 horses with mild or moderate asthma (MEA), and 16 horses with severe asthma (SEA)). Descriptive clinical and environmental parameters, bronchoalveolar lavage fluid cytology, and lung function data were extracted. There was no difference in serum 25(OH)D levels between healthy controls, horses with MEA, and horses with SEA (respectively, means of 57.9 ± 11.6, 55.6 ± 20.0, and 64.6 ± 14.5 nmol/L; p = 0.3), suggesting that this micronutrient does not play a major role in equine asthma pathophysiology. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To determine if multistrain probiotics administered to asthmatic cats treated with anti-inflammatory glucocorticoids would attenuate the asthmatic phenotype and beneficially alter respiratory, blood, and oropharyngeal (OP) microbial communities and immune parameters versus placebo. ANIMALS: 13 client-owned asthmatic cats. METHODS:A randomized, blinded, placebo-controlled clinical trial of asthmatic cats receiving anti-inflammatory glucocorticoids with oral multistrain probiotics or placebo assessed owner-perceived improvement and airway eosinophilia at baseline and after 2 weeks of treatment. Bronchoalveolar lavage fluid (BALF), blood, OP, and rectal microbial communities were compared using 16S rRNA amplicon sequencing. Real-time PCR for transcription factors, activation markers and cytokines, and IgA ELISAs were evaluated. Statistical analyses used 2-way repeated-measures ANOVA or permutational ANOVA (significance, P < .05). RESULTS: After treatment, there were no significant differences in owner-perceived clinical signs or mean ± SEM BALF eosinophils between groups. There was a significant decrease in rectal a-diversity but not in α- or β-diversity in BALF, blood, or OP between groups or over time. There were no significant differences in CD25, FoxP3, GATA, Helios, IL-4, IL-5, IL-10, IL-13, IL-17, IFN-γ mRNA, or serum or BALF IgA between groups or over time. [ABSTRACT FROM AUTHOR]

Abstract Background Reducing inhaled dust particles improves lung function in horses with severe asthma. Soaked hay is commonly used by owners, but its efficacy in improving lung function and inflammation has not been documented. Objectives To measure the effects of soaked hay and alfalfa pellets in horses with severe asthma. Animals Ten adult horses with severe asthma from a research colony. Methods Prospective controlled trial. Horses in clinical exacerbation were housed indoors and allocated to be fed either soaked hay (n = 5) or alfalfa pellets (n = 5) for 6 weeks. Soaked hay was immersed for 45 minutes and dried out hay was discarded between meals. Pulmonary function and clinical scores were measured before and after 2, 4, and 6 weeks. Tracheal mucus scores and bronchoalveolar lavages were performed before and after 6 weeks. Lung function was analyzed with a linear mixed model using log‐transformed data. Results Lung resistance decreased from (median (range)) 2.47 (1.54‐3.95) to 1.59 (0.52‐2.10) cmH2O/L/s in the pellets group and from 1.89 (1.2‐3.54) to 0.61 (0.42‐2.08) cmH2O/L/s in the soaked hay group over the 6‐week period for an average difference of 1.06 cmH2O/L/s for pellets (95% confidence interval [95% CI]: 0.09‐2.04, P = .03, not significant after correction) and 1.31 cmH2O/L/s for soaked hay (95% CI: −0.23 to 2.85, P

Simple Summary: It is important to minimize and optimize the use of antimicrobials to prevent resistance to these medications. Resistant bacteria can cause dangerous infections in people or animals. As in people, asthma in horses is considered non-infectious, so it is not necessary to use antimicrobials. However, in this this large survey completed by 249 equine veterinarians in 25 countries, we found that, just like general practitioners sometimes prescribe antimicrobials in human cases, 53% of the responding veterinarians stated to sometimes prescribe antimicrobials in asthma cases. We also tried to find out why and it became clear that knowledge of the pathophysiology of asthma, the country/culture the veterinarian works in, and the type of practice that they work in are important factors influencing prescription behavior. On the patient level, medical factors clearly predominate, possibly because several of these could also be compatible with infectious disease. This study underlines the need for further research on antimicrobials in equine asthma, the dissemination of knowledge of the pathophysiology of equine asthma, and clear (worldwide) guidelines on antimicrobial stewardship to diminish the inappropriate use of (critically important) antimicrobials in cases of equine asthma. Equine asthma is considered a non-infectious respiratory disease characterized by inflammation and hypersensitivity. Given the importance of antimicrobial stewardship, an international survey was designed to investigate the use of antimicrobials in asthmatic horses and the factors influencing prescription behavior. An online survey was distributed in six languages by international mailing lists and social media from December 2020 to January 2022. Of the 434 responses recorded, 249 veterinarians working in 25 countries finished the survey. These included 79 ECEIM/ACVIM diplomats. A total of 204 respondents confirmed national regulations concerning antimicrobial use in their country. Knowledge of the asthma definitions as presented in the revised ACVIM consensus statement was greater in veterinarians treating over 95% of equine patients compared to veterinarians treating more species, based on 10 questions (answers consistent with the consensus statement in 7 (IQR 5–9) and 4 (IQR 3–6) questions, respectively, (p < 0.001)). A total of 131 respondents stated to use antimicrobials (at least 'sometimes') in at least one of the three presented cases consistent with equine asthma. Trimethoprim-Sulfa combinations, penicillin(s), and tetracyclines were prescribed most (by 105, 53 and 38 veterinarians, respectively). Aminoglycosides, cephalosporins and fluoroquinolones were also selected (22, 15, 9 veterinarians respectively). Tetracyclines and cephalosporins are prescribed more often by veterinarians working without national regulations (p 0.019 and p 0.035, respectively). The most selected factors influencing prescription behavior were: 'tracheal wash culture' (62% of 131 veterinarians using antimicrobials in these cases), 'whether other horses in the barn have similar complaints' (60%), and 'response to other forms of therapy' (53%). In conclusion, insight into prescription behavior is the first step towards minimizing and optimizing antimicrobial use. [ABSTRACT FROM AUTHOR]

Simple Summary: Ex vivo, mouse, and human studies have pointed to the gut microbiota as playing roles in many diseases, including asthma susceptibility and severity. Equine asthma shares many similarities with human asthma, and gut microbiota could also be critical components in the pathophysiology of the disease. The purpose of this review was to describe the current knowledge on the potential role of the understudied gut–lung axis in the pathophysiology of equine asthma. Both microbe–microbe and host–microbe interactions can have effects beyond the local environment and influence immunological responses in remote organs such as the lungs. The crosstalk between the gut and the lungs, which is supported by complex connections and intricate pathways, is defined as the gut–lung axis. This review aimed to report on the potential role of the gut–lung gut–lung axis in the development and persistence of equine asthma. We summarized significant determinants in the development of asthma in horses and humans. The article discusses the gut–lung axis and proposes an integrative view of the relationship between gut microbiota and asthma. It also explores therapies for modulating the gut microbiota in horses with asthma. Improving our understanding of the horse gut–lung axis could lead to the development of techniques such as fecal microbiota transplants, probiotics, or prebiotics to manipulate the gut microbiota specifically for improving the management of asthma in horses. [ABSTRACT FROM AUTHOR]

Background: Reducing inhaled dust particles improves lung function in horses with severe asthma. Soaked hay is commonly used by owners, but its efficacy in improving lung function and inflammation has not been documented. Objectives: To measure the effects of soaked hay and alfalfa pellets in horses with severe asthma. Animals: Ten adult horses with severe asthma from a research colony. Methods: Prospective controlled trial. Horses in clinical exacerbation were housed indoors and allocated to be fed either soaked hay (n = 5) or alfalfa pellets (n = 5) for 6 weeks. Soaked hay was immersed for 45 minutes and dried out hay was discarded between meals. Pulmonary function and clinical scores were measured before and after 2, 4, and 6 weeks. Tracheal mucus scores and bronchoalveolar lavages were performed before and after 6 weeks. Lung function was analyzed with a linear mixed model using log‐transformed data. Results: Lung resistance decreased from (median (range)) 2.47 (1.54‐3.95) to 1.59 (0.52‐2.10) cmH2O/L/s in the pellets group and from 1.89 (1.2‐3.54) to 0.61 (0.42‐2.08) cmH2O/L/s in the soaked hay group over the 6‐week period for an average difference of 1.06 cmH2O/L/s for pellets (95% confidence interval [95% CI]: 0.09‐2.04, P =.03, not significant after correction) and 1.31 cmH2O/L/s for soaked hay (95% CI: −0.23 to 2.85, P <.001, significant). Conclusion and Clinical Importance: Soaked hay can control airway obstruction in horses with severe asthma. The strict protocol for soaking and discarding dried‐out hay in this study could however be considered too great of an inconvenience by owners. [ABSTRACT FROM AUTHOR]

ABSTRACTSLC26A9 is one out of 11 proteins that belong to the SLC26A family of anion transporters. Apart from expression in the gastrointestinal tract, SLC26A9 is also found in the respiratory system, in male tissues and in the skin. SLC26A9 has gained attention because of its modifier role in the gastrointestinal manifestation of cystic fibrosis (CF). SLC26A9 appears to have an impact on the extent of intestinal obstruction caused by meconium ileus. SLC26A9 supports duodenal bicarbonate secretion, but was assumed to provide a basal Cl- secretory pathway in airways. However, recent results show that basal airway Cl- secretion is due to cystic fibrosis conductance regulator (CFTR), while SLC26A9 may rather secrete HCO3-, thereby maintaining proper airway surface liquid (ASL) pH. Moreover, SLC26A9 does not secrete but probably supports reabsorption of fluid particularly in the alveolar space, which explains early death by neonatal distress in Slc26a9-knockout animals. While the novel SLC26A9 inhibitor S9-A13 helped to unmask the role of SLC26A9 in the airways, it also provided evidence for an additional role in acid secretion by gastric parietal cells. Here we discuss recent data on the function of SLC26A9 in airways and gut, and how S9-A13 may be useful in unraveling the physiological role of SLC26A9.

Simple Summary: Bronchoalveolar lavage (BAL) fluid cytology is considered the gold standard for the diagnosis of equine asthma both in terms of severity and type of lower airway inflammation. To process BAL fluid, cytocentrifugation is the most frequently employed procedure. The aim of this study was to investigate whether serial BAL cytological samples in horses with severe equine asthma (SEA) under different environmental conditions and medical treatment can undergo significant interpretative differences between two methods of preparation (cytocentrifugation and sediment smear). Considering cytocentrifugation as the reference method for evaluating BAL fluid in cytology, the sediment smear shows poor agreement in the differential cell count for neutrophils as well as lymphocytes and macrophages, with an overestimation of neutrophils and an underestimation of lymphocytes and macrophages. However, our results show that sediment smear, although it seems to be able to recognize the conditions of severe neutrophil respiratory disorders, does not appear overall to be overlapping in terms of differential cell count accuracy. Equine asthma is a common respiratory disease that may affect horses of any age. The diagnosis of severe equine asthma (SEA) (historically referred as recurrent airway obstruction or RAO) is based mainly on the history of the animal and clinical signs, which are further supported by the cytological examination of the bronchoalveolar lavage (BAL). This can also be helpful in monitoring the inflammation of the lower airways in response to environmental management and medication. The cytocentrifugated preparation is usually considered the method of choice for BAL cytological interpretation. The aim of this study was to compare the results in terms of differential cell counts (DCC) in BAL cytology performed on sedimented smears and cytocentrifugated preparations. To carry this out, 48 BAL samples were collected from six horses with SEA that were subjected to a process of exacerbation of the disease by environmental stimuli, which was later followed by the appropriate treatment. Each collected BAL fluid was equally divided into duplicate portions: one processed by cytocentrifugation and one by sediment smear from simple centrifugation. Cytologic examination of all BAL by both methods showed poor concordance in DCC, although it was still able to allow diagnostic recognition of severe lung neutrophilic disorders. These results suggest that sediment smear preparation, although remaining a useful method in general equine practice associated with clinical assessments in the diagnosis of SEA under conditions where there is no possibility of using a cytocentrifuge, cannot be considered a comparable alternative. [ABSTRACT FROM AUTHOR]

The 2019 Havemeyer Workshop brought together researchers and clinicians to discuss the latest information on Equine Asthma and provide future research directions. Current clinical and molecular asthma phenotypes and endotypes in humans were discussed and compared to asthma phenotypes in horses. The role of infectious and non-infectious causes of equine asthma, genetic factors and proposed disease pathophysiology were reviewed. Diagnostic limitations were evident by the limited number of tests and biomarkers available to field practitioners. The participants emphasized the need for more accessible, standardized diagnostics that would help identify specific phenotypes and endotypes in order to create more targeted treatments or management strategies. One important outcome of the workshop was the creation of the Equine Asthma Group that will facilitate communication between veterinary practice and research communities through published and easily accessible guidelines and foster research collaboration.

Objective: In severe equine asthma, structural remodeling of the airways ultimately leads to bronchial wall thickening and airflow obstruction. Increased bronchial vascularization has been described in horses affected by the severe form of the disease, but whether it contributes to bronchial remodeling in milder forms of asthma remains to be determined. In a blinded, retrospective case-control study, we evaluated the presence of bronchial angiogenesis in horses with mild and moderate equine asthma (MEA) and its correlation to airway smooth muscle remodeling., Methods: Endobronchial biopsies from the Equine Respiratory Tissue Biobank collected between August 14, 2014, and May 31, 2019, from 9 horses with MEA and 7 healthy controls were studied. The vascular basement membrane was identified by immunohistochemistry, allowing the measurement of the number of bronchial vessels, vascular area, and mean vessel size by histomorphometry. The correlations between angiogenic parameters, airway smooth muscle (ASM) remodeling features, and airway neutrophilia were studied., Results: No differences between groups were observed for the angiogenic parameters evaluated. The number of vessels was correlated to ASM cell proliferation in MEA horses (Spearman r = 0.73) but not in controls. Airway neutrophilia correlated negatively with mean vessel size in horses with MEA (Pearson r = -0.83) but not in control horses., Conclusions: Major changes in bronchial vascularization do not occur in central airways in MEA., Clinical Relevance: Contrary to previous findings in horses with severe equine asthma, angiogenesis is not a prominent feature of MEA, but it might be associated with ASM remodeling.

Abstract Background Equine asthma (EA) causes airflow impairment, which increases in severity with exercise. Electrical impedance tomography (EIT) is an imaging technique that can detect airflow changes in standing healthy horses during a histamine provocation test. Objectives To explore EIT‐calculated flow variables before and after exercise in healthy horses and horses with mild‐to‐moderate (MEA) and severe equine asthma (SEA). Animals Nine healthy horses 9 horses diagnosed with MEA and 5 with SEA were prospectively included. Methods Recordings were performed before and after 15 minutes of lunging. Absolute values from global and regional peak inspiratory (PIF, positive value) and expiratory (PEF, negative value) flows were calculated. Data were analyzed using a mixed model analysis followed by Bonferroni's multiple comparisons test to evaluate the impact of exercise and diagnosis on flow indices. Results Control horses after exercise had significantly lower global PEF and PIF compared to horses with SEA (mean difference [95% confidence interval, CI]: 0.0859 arbitrary units [AU; 0.0339‐0.1379], P

Equine asthma is a common respiratory disease that may affect horses of any age. The diagnosis of severe equine asthma (SEA) (historically referred as recurrent airway obstruction or RAO) is based mainly on the history of the animal and clinical signs, which are further supported by the cytological examination of the bronchoalveolar lavage (BAL). This can also be helpful in monitoring the inflammation of the lower airways in response to environmental management and medication. The cytocentrifugated preparation is usually considered the method of choice for BAL cytological interpretation. The aim of this study was to compare the results in terms of differential cell counts (DCC) in BAL cytology performed on sedimented smears and cytocentrifugated preparations. To carry this out, 48 BAL samples were collected from six horses with SEA that were subjected to a process of exacerbation of the disease by environmental stimuli, which was later followed by the appropriate treatment. Each collected BAL fluid was equally divided into duplicate portions: one processed by cytocentrifugation and one by sediment smear from simple centrifugation. Cytologic examination of all BAL by both methods showed poor concordance in DCC, although it was still able to allow diagnostic recognition of severe lung neutrophilic disorders. These results suggest that sediment smear preparation, although remaining a useful method in general equine practice associated with clinical assessments in the diagnosis of SEA under conditions where there is no possibility of using a cytocentrifuge, cannot be considered a comparable alternative.

Equine asthma is an important disease, known for centuries under various terminologies (heaves, chronic obstructive pulmonary disease, COPD; Recurrent Airway Obstruction, RAO; Inflammatory Airway Disease, IAD). Multiple endotypes exist in human asthma and it becomes more and more obvious that there may exist several subtypes in the horse as well, which may present with various clinical signs and may be associated with different prognoses and require different therapeutic approaches. In mild-moderate equine asthma, three subtypes have been described, characterized by increased percentages of neutrophil granulocytes>10%, mast cells>5% or eosinophil granulocytes>5% in bronchoalveolar lavage fluid (BALF) cytology. A further differentiation in mild (without clinical signs), moderate (with clinical signs, but without dyspnea at rest) and severe equine asthma (dyspnea at rest and severe neutrophilia>25% in BALF cytology) was suggested at the last Havemeyer Workshop, which focusses on this disease over the last 20 years on a regular basis, to support the early diagnosis of subclinical cases and initiate early therapy. New therapeutic approaches include inhalative application of glucocorticoids, which reach high concentrations in the lung due to their application as prodrugs and following metabolism in the lung, high lipophilia or low oral bioavailability. Lately, ciclesonide was approved for the German market. Further new approaches include immunostimulatory bacterial plasmids (CpG-ODNs) or the use of combination products. [ABSTRACT FROM AUTHOR]

Summary: The objectives were: 1. to investigate the occurrence of equine asthma syndrome (EAS) in a group of Campolina and Mangalarga Marchador horses through post‐exercise respiratory endoscopy and cytology; 2. compare the efficiency of different diagnostic criteria; and 3. compare the incidence of EAS by breed, age group and sex. A standardised exercise test was conducted in the field, followed by respiratory endoscopy and bronchoalveolar lavage and fluid collection 30 min post‐exercise. Clinical evaluation pre‐ and post‐exercise, respiratory endoscopy post‐exercise and bronchoalveolar lavage, also post‐exercise, were conducted in 30 horses (15 Campolina and 15 Mangalarga Marchador) aged 3–18 years, without a history of respiratory illness and without clinical evidence of active respiratory disease. All horses were in active training and were considered fit to participate in equestrian competition characteristic of these breeds. Post‐collection, the horses were subdivided into healthy or EAS‐positive, depending on several diagnostic criteria. Statistical comparisons between breeds, age brackets (up to 7 years of age and above 7 years of age) and sex were conducted using appropriate statistical tests. According to bronchoalveolar lavage fluid (BALF) cytology, 56.7% of the horses showed at least one inclusion criteria that contributed to classification as EAS‐positive. Of those, only one was classified as moderate EAS, while the others were classified as mild. Total cell count in the BALF above 530 cells/µL was the single most common diagnostic criteria (100%), followed by increased tracheal mucus (53%) at endoscopy, eosinophilia (47%) and neutrophilia (35%) in BALF. Significant differences were found between macrophage and lymphocyte numbers according to breed, but no other differences between breeds, age brackets, sex or status (healthy vs. EAS‐positive). A high occurrence of EAS was found in competition‐ready Mangalarga and Campolina pacer horses in this study. [ABSTRACT FROM AUTHOR]

Deviations from a core airway microbiota have been associated with the development and progression of asthma as well as disease severity. Pet cats represent a large animal model for allergic asthma, as they spontaneously develop a disease similar to atopic childhood asthma. This study aimed to describe the lower airway microbiota of asthmatic pet cats and compare it to healthy cats to document respiratory dysbiosis occurring with airway inflammation. We hypothesized that asthmatic cats would have lower airway dysbiosis characterized by a decrease in richness, diversity, and alterations in microbial community composition including identification of possible pathobionts. In the current study, a significant difference in airway microbiota composition was documented between spontaneously asthmatic pet cats and healthy research cats mirroring the finding of dysbiosis in asthmatic humans. Filobacterium and Acinetobacter spp. were identified as predominant taxa in asthmatic cats without documented infection based on standard culture and could represent pathobionts in the lower airways of cats. Mycoplasma felis, a known lower airway pathogen of cats, was identified in 35% of asthmatic but not healthy cats. This article has been published alongside “Temporal changes of the respiratory microbiota as cats transition from health to experimental acute and chronic allergic asthma” (1).

In humans, deviation from a core airway microbiota may predispose to development, exacerbation, or progression of asthma. We proposed to describe microbiota changes using 16 rRNA sequencing in samples from the upper and lower airways, and rectal swabs of 8 cats after experimental induction of asthma using Bermuda grass allergen, in acute (6 weeks) and chronic (36 weeks) stages. We hypothesized that asthma induction would decrease richness and diversity and alter microbiota composition and structure in the lower airways, without significantly impacting other sites. After asthma induction, richness decreased in rectal (p = 0.014) and lower airway (p = 0.016) samples. B diversity was significantly different between health and chronic asthma in all sites, and between all time points for lower airways. In healthy lower airways Pseudomonadaceae comprised 80.4 ± 1.3% whereas Sphingobacteriaceae and Xanthobacteraceae predominated (52.4 ± 2.2% and 33.5 ± 2.1%, respectively), and Pseudomonadaceae was absent, in 6/8 cats with chronic asthma. This study provides evidence that experimental induction of asthma leads to dysbiosis in the airways and distant sites in both the acute and chronic stages of disease. This article has been published alongside “Respiratory dysbiosis in cats with spontaneous allergic asthma” (1).

ABSTRACT: Bronchoalveolar lavage fluid (BALF) was analyzed to obtain information on leakage of acute-phase proteins from the blood into the respiratory lumen and about local synthesis. Ceruloplasmin, transferrin, albumin, α1-antitripsin, immunoglobulin G heavy, immunoglobulin G light, immunoglobulin A, haptoglobin, acidic glycoprotein, and P23 were measured in BALF from 30 horses without inflammatory disease by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). In serum, the same proteins were identified except for α1-antitrypsin. In conclusion, this study demonstrated that polyacrylamide gel electrophoresis (SDS-PAGE) can be used for the determination of acute-phase proteins in BALF samples from horses. In healthy horses, the values are very low, but they can be compared with reference values to assist in the diagnosis of animals with respiratory diseases.

Abstract Background There are limited data on potential dysbiosis of the airway microbiota in horses with asthma. Hypothesis/Objectives We hypothesized that the respiratory microbiota of horses with moderate asthma is altered. Our objectives were (a) to quantify tracheal bacterial populations using culture and qPCR, (2) to compare aerobic culture and qPCR, and (c) to correlate bacterial populations with bronchoalveolar lavage fluid (BALF) cytology. Animals Eighteen horses with moderate asthma from a hospital population and 10 controls. Methods Prospective case‐control study. Aerobic culture was performed on tracheal aspirates, and streptococci, Pasteurella multocida, Chlamydophila spp., Mycoplasma spp., as well as 16S (bacterial) and 18S (fungal) rRNA subunits were quantified by qPCR. Results Potential pathogens such as Streptococcus spp., Actinobacillus spp., and Pasteurellaceae were isolated from 8, 5, and 6 horses with asthma and 3, 0, and 2 controls, respectively. There was a positive correlation between Streptococcus spp. DNA and 16S rRNA gene (r ≥ 0.7, P ≤ 0.02 in both groups), but the overall bacterial load (16S) was lower in asthma (1.5 ± 1.3 versus 2.5 ± 0.8 × 104 copy/μL, P

Background: Equine asthma (EA) causes airflow impairment, which increases in severity with exercise. Electrical impedance tomography (EIT) is an imaging technique that can detect airflow changes in standing healthy horses during a histamine provocation test. Objectives: To explore EIT‐calculated flow variables before and after exercise in healthy horses and horses with mild‐to‐moderate (MEA) and severe equine asthma (SEA). Animals: Nine healthy horses 9 horses diagnosed with MEA and 5 with SEA were prospectively included. Methods: Recordings were performed before and after 15 minutes of lunging. Absolute values from global and regional peak inspiratory (PIF, positive value) and expiratory (PEF, negative value) flows were calculated. Data were analyzed using a mixed model analysis followed by Bonferroni's multiple comparisons test to evaluate the impact of exercise and diagnosis on flow indices. Results: Control horses after exercise had significantly lower global PEF and PIF compared to horses with SEA (mean difference [95% confidence interval, CI]: 0.0859 arbitrary units [AU; 0.0339‐0.1379], P <.001 and 0.0726 AU [0.0264‐0.1188], P =.001, respectively) and horses with MEA (0.0561 AU [0.0129‐0.0994], P =.007 and 0.0587 AU [0.0202‐0.0973], P =.002, respectively). No other significant differences were detected. Conclusions and Clinical Importance: Electrical impedance tomography derived PIF and PEF differed significantly between healthy horses and horses with SEA or MEA after exercise, but not before exercise. Differences between MEA and SEA were not observed, but the study population was small. [ABSTRACT FROM AUTHOR]

Bedding materials affect stable air hygiene, and thus the development and exacerbation of equine asthma. There is limited knowledge concerning the effects of different types of bedding material on equine lower airway inflammation. The objective of our study was to investigate the effects of bedding materials on respiratory signs, tracheal mucus score, and lower airway cytology in healthy adult horses. The study design was a prospective controlled study, and the subjects were healthy adult riding school horses (n = 32) from a single stable. Wood shavings were compared to peat, which was used as a reference bedding material. Lower airway endoscopy and sampling (tracheal wash and bronchoalveolar lavage fluid) for cytological examination were performed after each 35-day bedding period. No difference between bedding periods was observed in the respiratory rate or tracheal mucus score. Tracheal wash neutrophil percentage with the wood shavings was higher compared to the previous (P = 0.040) or following (P = 0.0045) peat period. Bronchoalveolar lavage fluid neutrophil percentage with the wood shavings was higher compared to the following peat period (P < 0.001). We conclude that, between the two bedding materials used in this study, peat caused less neutrophilic lower airway inflammation in horses. The information gained from this study may assist veterinarians and horse owners in selecting bedding materials, especially for horses suffering from equine asthma.

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 randomized cross-over design. AHR was defined by the histamine dose needed to double FOM baseline resistance, or to achieve a 35% increase in FP delta flow. Bronchoalveolar lavage fluid (BALF) was subsequently collected and stained with modified Wright's and toluidine blue stains. Binary statistical tests (related samples T-test, Mann-Whitney U, Chi-square analyses) were performed to compare study groups, with P < 0.05 considered significant. Abnormal BALF cytology confirmed EA in 14/19 (73.7%) horses. Both FOM and FP revealed AHR in 7/14 (50%) of these EA horses. An additional 4/19 (21.1%) horses showed AHR based on FP but not FOM, including two horses with normal BALF cytology. A diagnosis of AHR was more often associated with FP than FOM (P = 0.013), although the prevalence of AHR was significantly higher in EA vs. non-EA horses, regardless of testing methodology. The phase angle between thoracic and abdominal components of breathing did not differ between test groups. In conclusion, FP diagnosed AHR more frequently than did FOM, including horses with no other diagnostic evidence of EA. Without further evaluation, these two testing modalities of AHR cannot be used interchangeably.

Air pollution causes significant morbidity and mortality in patients with inflammatory airway diseases (IAD) such as allergic rhinitis (AR), chronic rhinosinusitis (CRS), asthma, and chronic obstructive pulmonary disease (COPD). Oxidative stress in patients with IAD can induce eosinophilic inflammation in the airways, augment atopic allergic sensitization, and increase susceptibility to infection. We reviewed emerging data depicting the involvement of oxidative stress in IAD patients. We evaluated biomarkers, outcome measures and immunopathological alterations across the airway mucosal barrier following exposure, particularly when accentuated by an infectious insult.

The 2019 Havemeyer Workshop brought together researchers and clinicians to discuss the latest information on Equine Asthma and provide future research directions. Current clinical and molecular asthma phenotypes and endotypes in humans were discussed and compared to asthma phenotypes in horses. The role of infectious and non-infectious causes of equine asthma, genetic factors and proposed disease pathophysiology were reviewed. Diagnostic limitations were evident by the limited number of tests and biomarkers available to field practitioners. The participants emphasized the need for more accessible, standardized diagnostics that would help identify specific phenotypes and endotypes in order to create more targeted treatments or management strategies. One important outcome of the workshop was the creation of the Equine Asthma Group that will facilitate communication between veterinary practice and research communities through published and easily accessible guidelines and foster research collaboration.

Inflammatory airway disease (IAD) is a commonly diagnosed but variably defined syndrome of equine lower airway inflammation. The most recent American College of Veterinary Internal Medicine (ACVIM) consensus statement, informed by research evidence, recommends a case definition based on clinical signs (poor performance or occasional coughing of at least 3 weeks duration), increased endoscopically-visible tracheal mucus, and bronchoalveolar lavage cytology, and proposes that the condition should be termed ‘mild-moderate equine asthma' (mEA). In British Thoroughbred racehorses, research to date has focused on airway inflammation defined by increased tracheal mucus and inflammatory tracheal wash sample cytology. It has been unclear whether or to what extent the ACVIM consensus statement has influenced the practice of British racing veterinarians. The aim of this qualitative study was to characterize and understand rationales for current practices relating to diagnosing and managing airway inflammation in British racehorses. Audio-recorded focus group discussions were conducted with 25 participants from four veterinary practices in England. Practices were purposively selected to represent those responsible for different types of racehorse, in different geographical regions. Thematic analysis of transcripts identified (i) an over-arching theme of serving the racing industry within which two further themes (ii) disregarding of the consensus and (iii) the pragmatic clinician were nested. The requirement to serve the racing industry was a key driver of clinical approaches, strongly influenced in particular by the trainer. Participants widely disregarded the consensus case definition of IAD/mEA for British racehorses because of perceived differences in etiology, perceived lack of practicability, particularly of BAL sampling, and perceived lack of understanding of the British racing context by consensus authors. Participants shared a strong professional identity as pragmatic clinicians providing an individualized clinical approach based on direct experience, which was often prioritized as the most valuable evidence with which to inform clinical decision-making. Lack of alignment with international consensus presents a barrier to practicing and furthering evidence-based medicine. Improved dialogue and partnership in research would be valuable and further research tailored for this population, including continuing development of contextually acceptable diagnostic methods, may be required.

Objectives: The aim of this study was to evaluate the results of serum allergen-specific IgE testing in cats with a clinical diagnosis of asthma and to determine if the number of allergens with positive IgE reactivity and magnitude of positive IgE responses would be associated with the severity of clinical signs or airway eosinophilia. Methods: Medical records from 2008 to 2018 were retrospectively reviewed. Inclusion required a diagnosis of feline asthma based on consistent clinicopathologic features and bronchoalveolar lavage (BAL) cytology with >10% eosinophils; additionally, cats needed to have the results of serum allergen-specific IgE tests. Results: Eighteen cases satisfied the inclusion criteria. Median age was 5 years and the most common presenting clinical sign was cough (n = 10/18). Most cats lived exclusively indoors (n = 13/18). The median percentage of BAL eosinophils was 47%. Serum allergen-specific IgE testing supported an underlying allergic etiology in 14/18 (78%) cats, with all but one having polysensitization. The severity of clinical signs and magnitude of airway eosinophilia did not correlate with the degree of positive IgE reactivity. Conclusions and relevance: This study identified a strong association between the identification of allergen-specific IgE and cats with asthma, and the majority of these cats were polysensitized. However, larger numbers of allergens with positive IgE reactivity or magnitude of IgE reactivity were not significantly associated with clinical severity or airway eosinophilia. Knowledge of positive allergen-specific IgE results could guide allergen avoidance, regardless of the magnitude of IgE reactivity. [ABSTRACT FROM AUTHOR]

Summary: Endoscopy, including bronchoalveolar lavage (BAL) fluid cytology, are invaluable tools for equine lower airway diagnostics. Objectives of the study were to evaluate the reliability of two staining methods, May–Grünwald–Giemsa (MGG) and toluidine blue (TB), for the evaluation of mast cells in cytospin smears from BAL fluid samples and the reliability of a 500‐cell differential cell count using both staining methods. Endoscopies and BAL fluid sampling were performed and BAL cytology was evaluated from cytospin smears. BAL cytology slides from 78 horses were evaluated. Three experienced observers evaluated the BAL cytology cytospin smears for the mast cell comparison study. The intra‐ and interobserver agreements were calculated using intraclass correlation coefficients (ICC). BAL cytology mast cell counts were significantly higher with the TB staining method compared with the MGG staining method. Observer agreements showed below acceptable agreement between observers for mast cell counts for both staining methods, even with fixed coordinates. Based on results from this study recommendation for BAL cytology staining would be to use both the MGG and the TB staining method, relying on the TB for the enumeration of mast cells. [ABSTRACT FROM AUTHOR]

Background: There are limited data on potential dysbiosis of the airway microbiota in horses with asthma. Hypothesis/Objectives: We hypothesized that the respiratory microbiota of horses with moderate asthma is altered. Our objectives were (a) to quantify tracheal bacterial populations using culture and qPCR, (2) to compare aerobic culture and qPCR, and (c) to correlate bacterial populations with bronchoalveolar lavage fluid (BALF) cytology. Animals Eighteen horses with moderate asthma from a hospital population and 10 controls. Methods: Prospective case‐control study. Aerobic culture was performed on tracheal aspirates, and streptococci, Pasteurella multocida, Chlamydophila spp., Mycoplasma spp., as well as 16S (bacterial) and 18S (fungal) rRNA subunits were quantified by qPCR. Results: Potential pathogens such as Streptococcus spp., Actinobacillus spp., and Pasteurellaceae were isolated from 8, 5, and 6 horses with asthma and 3, 0, and 2 controls, respectively. There was a positive correlation between Streptococcus spp. DNA and 16S rRNA gene (r ≥ 0.7, P ≤ 0.02 in both groups), but the overall bacterial load (16S) was lower in asthma (1.5 ± 1.3 versus 2.5 ± 0.8 × 104 copy/μL, P < 0.05). There was no association between microbial populations and clinical signs, tracheal mucus or BALF inflammation. Conclusions and Clinical Importance: This study does not support that bacterial overgrowth is a common feature of chronic moderate asthma in horses. Lower bacterial load could suggest dysbiosis of the lower airways, either as a consequence of chronic inflammation or previous treatments, or as a perpetuating factor of inflammation. [ABSTRACT FROM AUTHOR]

Equine asthma syndrome (EAS) is a common problem that affects horses of any age. Severe EAS is reported to affect 10–20% of adult horses in the northern hemisphere, while mild/moderate EAS is reported to affect 60–100% of adult horses, depending on the population and geographic region. For both severe and mild/moderate EAS, the presence of lower airway inflammation is attributed to airborne “triggers” such as dust, mold, and bacterial components that horses encounter in hay and stable-environments; and treatment recommendations for horses with EAS often include full-time pasture turnout. The caveat to this recommendation is horses with summer-pasture associated EAS (SP-EAS), who experience allergic lower airway inflammation when exposed to summer pasture. The prevalence of EAS in horses on pasture that do not have SP-EAS has not been reported. The purpose of this study was to use bronchoalveolar lavage (BAL) cytology to determine the prevalence of EAS in a herd of pastured, adult research horses with no history of respiratory disease. The horses were members of a teaching animal herd housed on pasture in the southeastern United States and fed round-bale Bermuda-grass hay. BAL fluid (BALF) cytology was analyzed in both summer (May–August 2017) and winter (November 2017–February 2018). Similar to previous reports, the prevalence of severe EAS in our study population was 10% in summer and 4.3% in winter. The prevalence of mild/moderate EAS was 60% in summer and 87% in winter. The high prevalence of mild/moderate EAS in this population was unexpected, given the 24-h, year-round pasture environment and the lack of history of respiratory disease. Additionally, 61.1% of horses with both summer and winter data had a different BALF cytology profile between the two seasons. To the authors' knowledge, this is the first study to use BAL cytology to diagnose, and monitor changes in, EAS phenotype in pastured adult horses. These results help to inform discussions regarding prevalence of EAS in pastured, adult horses in the southeastern region of North America.

Background: Fungi contribute to the inflammatory response of lungs in horses with recurrent airway obstruction and in some forms of asthma in humans. The role of fungi in inflammatory airway disease (IAD) has not been assessed. Objectives: Evaluate the prevalence of fungi in the respiratory samples of horses diagnosed with IAD, describe clinical signs associated with the presence of fungi in respiratory samples, and assess the risk factors associated with IAD and with the presence of fungi in the airways. Animals: Seven‐hundred thirty‐one active horses referred to a specialized ambulatory practice for signs of respiratory disease or poor performance. Methods: A prospective observational study was performed, collecting clinical data, environmental conditions, and results of a tracheal wash (TW; cytology, fungal culture, and bacterial culture), and bronchoalveolar lavage (cytology). Results: A positive fungal culture was obtained in 55% (402/731) of horses. Horses with fungal elements observed on the TW cytology had 2 times greater chance of having IAD than horses without fungi (odds ratio [OR] = 2.1; 95% CI 1.08‐3.33; P = .0003). Risks of being diagnosed with IAD and likelihood of fungi in TW were higher when horses were bedded on straw (OR = 2.0; 95% CI 1.2‐3.2 and OR = 1.9; 95% CI 1.3‐2.6, respectively) or fed dry hay (OR = 2.7; 95% CI 1.7‐4.4 and OR = 2.6; 95% CI 1.6‐3.4, respectively). Conclusions and Clinical Importance: Horses inhaling aerosolized fungal particles are at a significantly higher risk of developing IAD. The type of bedding and forage represent significant risk factors for IAD and fungal contamination of equine airways. [ABSTRACT FROM AUTHOR]

Summary: Background: Exhaled breath condensate (EBC) analysis is a noninvasive method to assess the lower respiratory tract. In human subjects, EBC hydrogen peroxide (H2O2), pH and leukotriene B4 (LTB4) are useful for detection and monitoring of inflammatory lung diseases, including asthma. Objectives: To determine associations between EBC biomarkers and cytological and endoscopic definitions of lower airway inflammation (LAI) while controlling for sampling and environmental variables. Study design: Prospective, cross‐sectional study. Methods: Clinical, endoscopic and airway cytological findings from 47 horses were compared with EBC pH and concentrations of H2O2 and LTB4 by univariate and multivariable analyses. Dichotomous (presence/absence of airway inflammation) and continuous outcome variables (differential cell counts in tracheal aspirate and bronchoalveolar lavage fluid, BALF) were evaluated and potential effects of collection and methodological factors were included. Results: EBC pH and H2O2 concentrations were higher in horses with LAI and both were positively associated with the percentage of neutrophils in BALF (P<0.05). Mast cell percentage in BALF was negatively associated with EBC pH, and BALF eosinophil percentage was positively associated with EBC LTB4 (P<0.05). Ambient temperature, relative humidity and assay methodology significantly impacted some analytes. Main limitations: LAI is challenging to categorise due to a variety of clinical and cytological phenotypes. Although the study was designed to overcome this limitation, numbers of horses were small in some categories. Conclusions: EBC pH and H2O2 concentrations are altered by airway inflammation, suggesting a role for these biomarkers in the diagnosis and monitoring of airway disease. Environmental and methodological factors can influence these biomarkers and should be considered in the interpretation of results. [ABSTRACT FROM AUTHOR]

Objective: To characterise the relationship between bronchoalveolar lavage fluid (BALF) cytology and pulmonary function testing with histamine bronchoprovocation (HBP) methods in a population of clinically normal horses. Design: Cross‐sectional study Methods: Clinically normal adult horses (n = 33) underwent pulmonary function testing and HBP with a commercial flowmetric plethysmography system. BAL was performed 1–5 days later. Statistical analysis was used to assess associations between BALF cell concentration, relative inflammatory cell percentages and categorisation, and airway hyper‐reactivity (AHR). Results: AHR (PC35 ≤ 8 mg/mL) was demonstrated in 17 (52%) of the horses. Using current definitions, BALF cytology was consistent with inflammatory airway disease in 14 (42%) of the horses and 7 of those demonstrated either mastocytic and/or eosinophilic responses. There was no correlation between total inflammatory cell counts or relative percentage and AHR. No statistical association was found between BALF inflammatory cell categories and AHR. Conclusion: A direct association between cytological evidence of airway inflammation and AHR was not identified in this population of clinically normal horses. Determining the presence and measuring inflammatory cell mediators in BALF may more accurately reflect AHR. In addition, normal values for cell proportions in BALF may vary between different populations of horses and more appropriate regional reference ranges should be established. [ABSTRACT FROM AUTHOR]

Leukotriene B4 (LTB4) is a potent chemoattractant that can recruit and activate immune cells such as neutrophils, eosinophils, and monocytes to sites of inflammation. Excessive production of LTB4 has been linked to acute and chronic inflammatory diseases, including asthma, rheumatoid arthritis, and psoriasis. Inhibiting the binding of LTB4 to its receptors, BLT1 and BLT2, is a potential strategy for treating these conditions. While several BLT1 antagonists have been developed for clinical trials, most have failed due to efficacy and safety issues. Therefore, discovering selective BLT2 antagonists could improve our understanding of the distinct functions of BLT1 and BLT2 receptors and their pharmacological implications. In this study, we aimed to discover novel BLT2 antagonists by synthesizing a series of biphenyl analogues based on a BLT2 selective agonist, CAY10583. Among the synthesized compounds, 15b was found to selectively inhibit the chemotaxis of CHO-BLT2 cells with an IC 50 value of 224 nM without inhibiting the chemotaxis of CHO-BLT1 cells. 15b also inhibited the binding of LTB4 and BLT2 with a Ki value of 132 nM. Furthermore, 15b had good metabolic stability in liver microsomes and moderate bioavailability (F = 34%) in in vivo PK studies. 15b also showed in vivo efficacy in a mouse model of asthma, reducing airway hyperresponsiveness by 59% and decreasing Th2 cytokines by up to 46%. Our study provides a promising lead for the development of selective BLT2 antagonists as potential therapeutics for inflammatory airway diseases such as asthma and chronic obstructive pulmonary disease. [Display omitted] • LTB4 mediates the recruitment and activation of immune cells to sites of inflammation via BLT1 and BLT2 receptors. • SAR study of derivatives of CAY10583, a BLT2 selective agonist, were conducted. Several antagonists were discovered. • Compound 15b exhibited selective BLT2 antagonistic activity with an IC 50 of 224 nM in a BLT2-mediated cell migration assay. • The PK profile of 15b in rats suggested the potential for P.O., with a bioavailability of 34.8% at 20 mg/kg for the solution. • Compound 15b reduced AHR by 59% and Th2 cytokines production by 35–46% in an LPS-induced asthma animal model. [ABSTRACT FROM AUTHOR]

Clinical examination, bronchoalveolar lavage fluid (BALF) cytology, acute-phase protein, and pulmonary hemostasis and fibrinolysis marker (fibrinogen, serum amyloid A [SAA], and D-dimer) results were compared between control and respiratory disease-affected horses. Using a clinical scoring system, horses (n = 58) were classified as respiratory disease-free (Controls, n = 15) or with recurrent airway obstruction (RAO; n = 18), inflammatory airway disease (n = 14) or chronic interstitial pneumopathy (n = 11). There were no significant differences in fibrinogen concentrations among groups, but there was a trend toward a lower value in controls (median 0.0024 g/L) than in horses with chronic pneumopathies (median 0.0052 g/L), in particular, those with RAO (median 0.0062 g/L). Fibrinogen concentration was positively correlated with percentage of neutrophils in BALF (rs = 0.377, p = 0.004). SAA concentrations were low; 65.5% of samples were below the detection limit. D-dimer concentrations were also low and quantifiable concentrations were only obtained after ultrafiltration and only in RAO (median 0.1 mg/L). In conclusion, there was limited evidence of increased coagulatory activity in chronic pneumopathies, apart from RAO. It is uncertain whether fibrinogen and D-dimer concentrations increased due to their role as acute-phase proteins or as a misbalance of coagulation and fibrinolysis. [ABSTRACT FROM AUTHOR]

Mycoplasma equirhinis and Mycoplasma felis are thought to be infectious etiologic agents of inflammatory airway disease (IAD), which, after musculoskeletal injuries, is the second most common cause of poor performance in thoroughbred racehorses. The aims of this study were to investigate for the first time the presence of M. equirhinis, M. felis, and other Mycoplasma spp. in the lower respiratory tract of racehorses in İstanbul Province in Turkey and to statistically evaluate the association between clinical signs of IAD and the presence of mycoplasmas. Tracheal wash (TW) samples were collected from 111 English and Arabian thoroughbred horses that showed clinical signs of IAD. TW samples were examined by culture and PCR methods. The detection rates of Mycoplasma spp., M. felis, and M. equirhinis were found to be 16.2%, 0%, and 18% by culture and 59.5%, 1.8%, and 6.3% by PCR in TW samples, respectively. According to statistical evaluations, a significant association was found for the presence of M. felis in English thoroughbred racehorses. However, no significant association was found between clinical signs of IAD and the presence of M. equirhinis, M. felis, and other Mycoplasma spp. [ABSTRACT FROM AUTHOR]

Pulmonary inflammatory diseases have been observed in equine since their domestication. Non-infectious disease processes of the lower airways are amongst the most important diseases of the equine respiratory tract. This study aims to determine the cytology profile and effect of age on the evaluation of equine bronchoalveolar lavage (BAL) obtained from healthy animals and from horses with asymptomatic inflammatory airway disease (IAD). Thirty two horses, including 20 males and 12 females, without clinical signs of pulmonary disease and with age varying from 4 to 21 years, were assigned to two groups: 15 animals in the control group and 17 in the asymptomatic group. Groups were divided according to physical examination and mucous accumulation observed during tracheal endoscopy. The BAL results from healthy and asymptomatic horses were, respectively: 56.9% and 48.0% macrophages, 37.2% and 40.0% lymphocytes, 3.3% and 7.1% neutrophils, 1.7% and 1.4% mast cells, 0.3% and 0.7% eosinophils; 0,5% and 0.4% epithelial cells. When horses in the two groups were analyzed according to their age range, no differences were found. In conclusion, IAD in the asymptomatic group was significantly different from the control group. The asymptomatic horses presented a discrete infiltrate of neutrophils, which does not influence cytological evaluation of BAL.Doenças inflamatórias pulmonares são observadas na espécie equina desde sua domesticação. Dentre as enfermidades de maior importância do trato respiratório equino, estão os distúrbios não infecciosos de vias aéreas posteriores. Este trabalho teve por objetivo determinar o perfil citológico e o efeito da idade na avaliação do lavado broncoalveolar (LBA) de equinos sadios e com Doença Inflamatória das Vias Aéreas (DIVA) assintomática. Foram utilizados 32 equinos adultos, aparentemente sadios, de ambos os sexos (20 machos e 12 fêmeas), com faixa etária média semelhante, sendo 15 animais do grupo controle e 17 animais do grupo doente assintomático. Os grupos foram estabelecidos segundo os critérios de GERBER et al. (2004) para acúmulo de muco traqueal após a realização de exames físicos diretos e endoscopia traqueal. Foi realizado o LBA e o percentual dos valores médios obtidos na análise citológica dos cavalos sadios e com DIVA assintomática foram, respectivamente: 56,9% e 48,0% de macrófagos, 37,2% e 40,0% de linfócitos, 3,3% e 7,1% de neutrófilos, 1,7% e 1,4% de mastócitos, 0,3% e 0,7% de eosinófilos; e 0,5% e 0,4% de células epiteliais. Concluiu-se que a DIVA nos animais integrantes do grupo doente assintomático caracterizou- se por um discreto infiltrado de neutrófilos e que a idade não influencia na avaliação citológica do LBA.

Background: Procalcitonin (PCT), a precursor protein of the hormone calcitonin, is a sensitive inflammatory marker in human medicine, which is primarily used for diagnosis of bacterial sepsis, but is also useful in diagnosis of exacerbation of asthma and COPD. In this study, PCT was evaluated as a potential biomarker for different chronic pneumopathies in the horse using an equine specific ELISA in comparison to established clinical markers and different interleukins. Sixty-four horses were classified as free of respiratory disease, recurrent airway obstruction (RAO), inflammatory airway disease (IAD) or chronic interstitial pneumopathy (CIP) using a scoring system. PCT concentrations were measured in plasma (n = 17) and in the cell-free supernatant of bronchoalveolar lavage (n = 64). PCT concentrations were correlated to interleukins IL-1ß and IL-6 in BALF, clinical findings and BALF cytology. Results: The median PCT concentrations in plasma were increased in respiratory disease (174.46 ng/ml, n = 7) compared to controls (13.94 ng/ml, n = 10, P = 0.05) and correlated to PCT in BALF supernatant (rs = 0.48). Compared to controls (5.49 ng/ml, n = 15), median PCT concentrations in BALF supernatant correlated to the overall clinical score (rs = 0.32, P = 0.007) and were significantly increased in RAO (13.40 ng/ml, n = 21) and IAD (16.89 ng/ml, n = 16), while no differences were found for CIP (12.02 ng/ml, n = 12). No significant increases were found for IL-1 and IL-6 between controls and respiratory disease in general as well as different disease groups. Conclusions: Although some correlations were found between PCT in plasma, BALF supernatant and clinical scores, PCT in BALF does not seem to be a superior marker compared to established clinical markers. PCT in plasma seems to be more promising and a greater number of samples should be evaluated in further studies. [ABSTRACT FROM AUTHOR]

Background: The potential involvement of viruses in inflammatory airway disease (IAD) was previously investigated through either serology or PCR from nasopharyngeal swabs (NS). The aims of this study were to determine the prevalence and incidence of viral genome detection by qPCR in the equine airways, and their association with respiratory clinical signs. Methods: Both NS and tracheal washes (TW) were collected monthly on 52 Standardbred racehorses at training, over 27 consecutive months (581 samples). Equid herpesviruses (EHV)-1, -4, -2 and -5, equine rhinitis virus-A and -B (ERBV), equine adenovirus-1 and -2, equine coronavirus and equine influenza virus were systematically investigated in both NS and TW. Nasal discharge, coughing, tracheal mucus score and TW neutrophil proportions were simultaneously recorded. Results: Genome for 7/10 viruses were detected at least once throughout the study; up to 4 different viruses being also concomitantly detected. Monthly incidence in TW was respectively 27.9% (EHV-5), 24.8% (EHV-2), 7.1% (ERBV), 3.8% (EHV-4), 1.9% (EAdV1) and 0.2% (EHV-1; ERAV). Neither agreement nor correlation between NS and TW was found for respectively genome detection and viral loads. Detection of viral genome in NS was not associated with any clinical sign. Coughing was significantly associated with TW detection of EHV-2 DNA (OR 3.1; P = 0.01) and ERBV RNA (OR 5.3; P < 0.001). Detection of EHV-2 DNA in TW was also significantly associated with excess tracheal mucus (OR 2.1; P = 0.02). Conclusions: Detection and quantification of EHV-2 and ERBV by qPCR in TW, but not in NS, should be considered when investigating horses with IAD. [ABSTRACT FROM AUTHOR]

Reasons for performing study Agreement between airway reactivity measured by flowmetric plethysmography and histamine bronchoprovocation, and lower airway inflammation measured by bronchoalveolar lavage ( BAL) cytology, has not been studied in horses with suspected inflammatory airway disease ( IAD). Objectives We tested the hypothesis that airway reactivity is associated with BAL cytology in horses presenting for unexplained poor performance and/or chronic cough. Study design Prospective clinical study. Methods Forty-five horses, predominantly young Standardbred racehorses, presenting for unexplained poor performance or chronic cough, underwent endoscopic evaluation, tracheal wash, flowmetric plethysmography with histamine bronchoprovocation and BAL. Histamine response was measured by calculating PC35, the concentration of nebulised histamine eliciting an increase in Δflow of 35%. Results In this population, there was no significant correlation between histamine response and cell populations in BAL cytology. When airway hyperreactivity ( AHR) was defined as ≥35% increase in Δflow at a histamine concentration of <6 mg/ml, 24 of the 45 horses (53%) were determined to have AHR. Thirty-three (73%) had either abnormal BAL cytology or AHR, and were diagnosed with IAD on this basis. Of horses diagnosed with IAD, 9 (27%) had an abnormal BAL, 11 (33%) had AHR and 13 (39%) had both. Conclusions Airway reactivity and BAL cytology did not show concordance in this population of horses presenting for unexplained poor performance and/or chronic cough. Failure to include tests of airway reactivity may lead to underdiagnosis of IAD in young Standardbred racehorses that present with clinical signs suggestive of IAD. [ABSTRACT FROM AUTHOR]

Pendrin (SLC26A4) is a Cl-/anion exchanger expressed in the epithelium of inflamed airways where it is thought to facilitate Cl- absorption and HCO3-secretion. Studies using pendrin knockout mice and airway epithelial cells from hearing-impaired subjects with pendrin loss of function suggest involvement of pendrin in inflammatory lung diseases, including cystic fibrosis (CF), perhaps by regulation of airway surface liquid (ASL) volume. Here we identified small-molecule pendrin inhibitors and demonstrated their efficacy in increasing ASL volume. A cell-based, functional high-throughput screen of ~36,000 synthetic small molecules produced 3 chemical classes of inhibitors of human pendrin. After structure-activity studies, tetrahydropyrazolopyridine and pyrazolothiophenesulfonamide compounds reversibly inhibited pendrin-facilitated Cl- exchange with SCN-, I-, NO3-, and HCO3- with drug concentration causing 50% inhibition down to ~2.5 µM. In well-differentiated primary cultures of human airway epithelial cells from non-CF and CF subjects, treatment with IL-13, which causes inflammation with strong pendrin up-regulation, strongly increased Cl-/HCO3- exchange and the increase was blocked by pendrin inhibition. Pendrin inhibition significantly increased ASL depth (by ~8 µm) in IL-13-treated non-CF and CF cells but not in untreated cells. These studies implicate the involvement of pendrin-facilitated Cl-/HCO3- in the regulation of ASL volume and suggest the utility of pendrin inhibitors in inflammatory lung diseases, including CF. [ABSTRACT FROM AUTHOR]