Myeloperoxidase concentration in bronchoalveolar lavage fluid from healthy horses and those with recurrent airway obstruction

in Canadian Journal of Veterinary Research = Revue Canadienne de Recherche Vétérinaire (2006), 70(4), 291-296

The aim of this work was to measure the myeloperoxidase (MPO) concentration in bronchoalveolar lavage (BAL) fluid collected from horses with recurrent airway obstruction (RAO), both in crisis and in ... [more ▼]

The aim of this work was to measure the myeloperoxidase (MPO) concentration in bronchoalveolar lavage (BAL) fluid collected from horses with recurrent airway obstruction (RAO), both in crisis and in remission, as well as from healthy horses. Seven horses with RAO were exposed to moldy hay until the maximum change in pleural pressure was greater than 1.5 kPa. At that point, BAL was performed, and the total cell counts and percentages in the fluid were immediately determined. To measure the MPO concentration in BAL-fluid supernatant, we used a specific enzyme-linked immunosorbent assay with polyclonal antibodies against equine MPO. The tests were repeated on the horses with RAO after they had spent 2 mo on pasture. Six healthy horses serving as controls underwent the same tests. The absolute and relative neutrophil counts and the MPO concentration in the BAL fluid were significantly greater in the horses with an RAO crisis than in the control horses. After 2 mo on pasture, the horses that had been in RAO crisis were clinically normal, and their neutrophil counts and MPO levels in BAL fluid had significantly decreased; during remission their neutrophil counts were not significantly different from those in the healthy horses, but their MPO concentration remained significantly higher. This study showed that determining the MPO concentration in a horse's BAL fluid is technically possible and that during remission from RAO the concentration remains higher than normal. Thus, MPO may be a marker of neutrophil presence and activation in the lower airways. [less ▲]

Qualitative and quantitative evaluation of equine respiratory mechanics by impulse oscillometry.

in Equine Veterinary Journal (2006), 38(1), 52-58

REASONS FOR PERFORMING STUDY: The long-established conventional reference technique (CRT) for measuring respiratory mechanics in horses lacks sensitivity and there is a need for further refinement in new ... [more ▼]

REASONS FOR PERFORMING STUDY: The long-established conventional reference technique (CRT) for measuring respiratory mechanics in horses lacks sensitivity and there is a need for further refinement in new technology, such as the impulse oscillometry system (IOS). OBJECTIVES: To evaluate the potential use of the IOS as a clinical respiratory function test and compare it to the current CRT in horses suffering from common upper and lower airway dysfunctions. METHODS: Six healthy horses were tested before and after induction of a unilateral nasal obstruction (UNO) or transient left laryngeal hemiplegia (LLH). Six heaves-affected horses were tested in clinical remission and during a heaves crisis, before and after nebulisation of cumulative doses of a bronchodilator therapy (ipratropium bromide; IPB). RESULTS: As opposed to the CRT, the IOS was able to detect partial upper airway obstruction (UAO) caused by UNO or LLH in resting horses, without differentiating both conditions. Upper airway obstruction caused an upward shift of resistance (R(rs)) from 5 to 35 Hz without altering reactance (X(rs)). As for the CRT, IOS respiratory parameters measured in heaves-affected horses in crisis differed significantly from values measured during remission. The difference in frequency-dependent behaviour of R(rs) and X(rs) allowed discrimination between upper and lower airway obstructions. Bronchodilator treatment induced significant dose-dependent changes in X(rs) at 5 and 10 Hz, from the first dose. Total pulmonary resistance (RL) and R(rs) at 5 Hz were affected from the second dose and displayed similar sensitivity. Although post treatment RL values were comparable to remission, R(rs) and X(rs) remained significantly different, characterising persistent peripheral obstruction. CONCLUSIONS: The IOS was more sensitive than the CRT in detecting partial UAO in resting horses and persistent post treatment peripheral dysfunction in heaves-affected horses. The IOS is a sensitive test that provides graded quantitative and qualitative information on disease-induced respiratory dysfunctions as well as on treatment efficiency in horses. POTENTIAL RELEVANCE: The IOS could represent a practical and sensitive alternative respiratory function test for routine clinical investigations of common airway obstructive diseases and therapy in horses. [less ▲]

Cardiac pumping reserve measured in healthy horses using a dobutamine stress test

in Proceedings of the 45th Congress of the British Equine Veterinary Association (2006)

Evaluation des troubles fonctionnels du système respiratoire du cheval

in Pratique Vétérinaire Equine (2006), 38(150), 29-39

Les troubles respiratoires sont fréquents chez le cheval. Il existe des tests fonctionnels complémentaires, réalisables soit sur le terrain soit en centres spécialisés.

Effect of exercise on blood oxidant/antioxidant markers in standardbred horses: comparison between treadmill and race track tests.

in Equine Veterinary Journal. Supplement (2006), (36), 254-257

REASONS FOR PERFORMING STUDY: Interest in establishing oxidant/ antioxidant profiles in competition horses is increasing. Earlier studies performed in horses have mainly been performed under laboratory ... [more ▼]

REASONS FOR PERFORMING STUDY: Interest in establishing oxidant/ antioxidant profiles in competition horses is increasing. Earlier studies performed in horses have mainly been performed under laboratory conditions using a treadmill and it is not known to what extent laboratory results of oxidant/antioxidant studies might be transposed to field conditions. OBJECTIVE: To compare the impact on the blood oxidant/ antioxidant status of a standardised exercise test including a run up to fatigue performed on a treadmill (TM) and on a racetrack (RT) in healthy and trained Standardbred horses. MATERIAL AND METHODS: During TM and RT tests the following blood antioxidant markers were analysed in jugular venous blood at rest and 15 mins (E15) after an intense bout of exercise: uric acid (UA), ascorbic acid (AA), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione (reduced: GSH and oxidised: GSSG), glutathione redox ratio (GRR) and protein thiol (PSH). Running time to fatigue (RTF), velocity during the last exercise stage (Vmax), final heart rate (HRfinal) and venous lactic acid (LA) were also recorded. RESULTS: Vmax was significantly (P<0.05) higher during the RT, whereas LA was significantly lower. HRfinal and RTF did not differ significantly between TM and RT. Exercise induced a significant increase (R vs. E15) of UA and AA in both tests, whereas GSH and PSH decreased significantly. GPx, SOD, GSSG and GRR remained unchanged. Differences between TM and RT were significant at E15 for UA, AA and PSH. CONCLUSIONS: Comparison of oxidant/antioxidant profiles from laboratory and field studies are difficult to standardise and should be interpreted with caution. POTENTIAL RELEVANCE: For the same RTF and final HR, the TM induced stronger changes in blood lactate and in blood oxidant/antioxidant balance than did RT. [less ▲]

DNA binding activity of transcription factors in bronchial cells of horses with recurrent airway obstruction.

in Veterinary Immunology and Immunopathology (2006), 113(1-2), 11-20

Horses with recurrent airway obstruction (RAO) present many similarities with human asthmatics including airway inflammation, hyperresponsiveness, reversible obstruction, and increased NF-kappaB ... [more ▼]

Horses with recurrent airway obstruction (RAO) present many similarities with human asthmatics including airway inflammation, hyperresponsiveness, reversible obstruction, and increased NF-kappaB expression. Studies in experimental asthma models have shown that transcriptions factors such as activator protein-1 (AP-1), GATA-3, cyclic AMP response element binding protein (CREB) and CAAT/enhancer binding protein (C/EBP) may also play an important role in airway inflammation. The purpose of this study was to measure DNA binding activity of these transcription factors in the airways of horses with RAO and to compare it to pulmonary function and bronchoalveolar lavage fluid (BALF) cytology. Seven horses with RAO and six control animals were studied during a moldy hay challenge and after 2 months at pasture. Pulmonary function, BALF cytology and transcription factors' activities in bronchial brushings were measured during hay and pasture exposures. During moldy hay challenge, RAO-affected horses developed severe airway obstruction and inflammation and a significantly higher airway AP-1 binding activity than in controls. After 2 months on pasture, pulmonary function and airway AP-1 binding activity were not different between RAO and control horses. The DNA binding activity of CREB in airways of RAO-affected horses increased significantly after 2 months at pasture and became higher than in controls. A significant positive correlation was detected between AP-1 binding activity and indicators of airway obstruction and inflammation. Airway GATA-3, CEBP and CREB binding activities were negatively correlated with indices of airway obstruction. However, contrarily to CREB binding activity, GATA-3 and CEBP binding activities were not different between RAO and control horses and were unaffected by changes in environment. These data support the view that AP-1 and CREB play a role in modulating airway inflammation in horses with RAO [less ▲]

Le nez électronique, un nouvel outil diagnostique pour les maladies respiratoires du cheval ?

in Proceedings: AVEF, Versailles, France (2006)

Traitements médicaux du système respiratoire: 2-broncho-dilatateurs et autres substances

in Pratique Vétérinaire Equine (2006), 38

The medical therapeutic arsenal available to the practitioner for treatment of respiratory conditions in horses is growing because of new drugs being introduced on the market, the marketing authorisation ... [more ▼]

The medical therapeutic arsenal available to the practitioner for treatment of respiratory conditions in horses is growing because of new drugs being introduced on the market, the marketing authorisation obtained for certain existing active ngredients, the possibility of using medicines authorised for humans and the development of aerosoltherapy. Nevertheless treatment remains empirical in the absence of a precise diagnosis, and the use of particular medicines may be unjustified and even erroneous, and in addition treatment fa ures can be discouraging and costly for the owner. However, when the diagnosis is established, combination of several medicines can silmificaxrtly and rapidly improve clinical signs and/or performance, and avoid sequelae and recurrence. In this article brief information is given on management of the environment followed by a very complete list of medicines used in horses with respirrtory conditions. The différent active ingredients available are listed by category and these includé antimicrobials, anti-inflammatories, bronchodilatators, mucolytics immune stimulants and other substances. Dosages, indications, pharmacokinetic properties, possible secondary effects and contra-indications are complied from a avide literature review. The essential considerations when deciding which treatment to use are discussed, in particular the effectiveness of the treatment for the disease, the mode of administration and the potential cost [less ▲]

La "fausse grippe" ou le syndrome inflammatoire des voies aeriennes du cheval de sport

in Nouveau Praticien Vétérinaire Equine (2005), (24-juin/juillet/août), 24-28

Objectif: prévenir, reconnaître et traiter le syndrome inflammatoire des voies aériennes du cheval de sport.

Traitement des problèmes du système respiratoire profond

in Proceedings: 9th Congress on Equine Medicine and Surgery (2005)

Lower respiratory troubles in mature sports horses mainly include viral diseases (influenza, rhinopneumonia) ; bacterial diseases (that are generally due to commensal bacteria invading the lower ... [more ▼]

Lower respiratory troubles in mature sports horses mainly include viral diseases (influenza, rhinopneumonia) ; bacterial diseases (that are generally due to commensal bacteria invading the lower respiratory tract because of an impairment of the pulmonaty defences); inflammatory processes (mainly in horses suffering from heaves and inflammatory airway disease) and exercise-induced pulmonary haemorrhages. Dysfunction such as hypersecretion of mucus, bronchospasms, bronchial hypereactivity and oedema may complicate any of this diseases. Treatments focusing on the etiological agents (anti-viral therapy, modulation of immunity, and antibiotic therapy), on the associated symptoms (anti-inflammatory, bronchodilators, regulator of the muco-ciliary clearance) and on the nursing and general management (rest and environmental hygiene) are described in this review [less ▲]