Bronchial angiogenesis in horses with severe asthma and its response to corticosteroids.

BACKGROUND: Severe asthma in horses is characterized by structural changes that thicken the lower airway wall, a change that is only partially reversible by current treatments. Increased vascularization contributes to the thickening of the bronchial wall in humans with asthma and is considered a potential new therapeutic target. OBJECTIVE: To determine the presence of angiogenesis in the bronchi of severely asthmatic horses, and if present, to evaluate its reversibility by treatment with corticosteroids. ANIMALS: Study 1: Bronchial samples from asthmatic horses in exacerbation (7), in remission (7), and aged-matched healthy horses. Study 2: Endobronchial biopsy samples from asthmatic horses in exacerbation (6) and healthy horses (6) before and after treatment with dexamethasone. METHODS: Blinded, randomized controlled study. Immunohistochemistry was performed using collagen IV as a marker for vascular basement membranes. Number of vessels, vascular area, and mean vessel size in the bronchial lamina propria were measured by histomorphometry. Reversibility of vascular changes in Study 2 was assessed after 2 weeks of treatment with dexamethasone. RESULTS: The number of vessels and vascular area were increased in the airway walls of asthmatic horses in exacerbation (P = .01 and P = .02, respectively) and in remission (P = .02 and P = .04, respectively) when compared to controls. In Study 2, the differences observed between groups disappeared after 2 weeks of treatment with corticosteroids because of the increased number of vessels in healthy horses. CONCLUSIONS AND CLINICAL IMPORTANCE: Angiogenesis contributes to thickening of the airway wall in asthmatic horses and was not reversed by a 2-week treatment with corticosteroids.

Pulmonary response of severely asthmatic horses after intra-articular administration of methylprednisolone.

BACKGROUND: Intra-articular (IA) administration of corticosteroids is performed routinely in equine practice. The lung function of severe asthmatic horses has recently been shown to be improved by IA triamcinolone acetonide (TA). We therefore hypothesised that IA methylprednisolone acetate (MPA), another commonly used corticosteroids, would also decrease the airway obstruction in severe asthmatic horses. OBJECTIVES: To compare the effects of intra-articular (IA) and intramuscular (IM) methylprednisolone acetate (MPA) administration on lung function and serum cortisol levels in horses with severe asthma. STUDY DESIGN: Randomised and controlled experiments on severe asthmatic research animals. METHODS: Severe asthmatic horses in exacerbation were administered 200 mg of MPA either intramuscularly (n = 6) or via intra-articular injections in the tarsocrural joints (n = 6; 100 mg/joint). Serum cortisol concentration and pulmonary function was measured for 8 days. RESULTS: A significant decrease in pulmonary resistance in the IA group (P = .003, mean diff 1.14) on day 1 in comparison with baseline was observed. A significant decrease from baseline was also observed on serum cortisol values in the IA group 6 hours after injection (P = .001, mean diff 44.5), and at day 1 (P = .003, mean diff 45.1). MAIN LIMITATIONS: Joint health was not evaluated in the current study and the physiological response of the severe asthmatic horses might deviate from that of the milder forms of asthma. CONCLUSIONS: MPA IA administration improves the lung function of severe asthmatic horses. However, this effect was mild and of a short duration.

Randomized Comparative Trial of Acupuncture and Exercise Versus Uterine Ecbolics in the Treatment of Persistent Postbreeding Endometritis in Mares.

Although exercise and acupuncture are frequently used therapies to treat persistent postbreeding endometritis, their efficacy to date is unproven. The objective of this study was to determine if exercise and acupuncture are effective methods to reduce intrauterine fluid and compare the effectiveness of these treatments to the use of uterine ecbolics. Twelve mares susceptible to postbreeding endometritis were enrolled in the study with a randomized cross-over design using both positive and negative controls. During each estrous cycle, mares were randomized into one of six treatment groups, including stall rest (SR), oxytocin, cloprostenol, exercise, electroacupuncture, and oxytocin and exercise. Each mare was challenged with an insemination dose of 500 × 106 dead sperm at time 0 hours. Intrauterine fluid measurements were taken at 0, 4, 24, 48, 72, and 96 hours postbreeding. Associations between treatment efficacy and fluid clearance were investigated using a random-effects logistic regression model that controlled for positive uterine culture. Compared with the SR negative control, exercise was the most effective treatment and had 29.7 times increased odds of fluid clearance. The second most effective treatment was oxytocin alone, with 16.9 times increased odds of fluid clearance. This was followed by cloprostenol that had 10.6 greater odds of fluid clearance, and finally, the treatment that combined exercise with oxytocin had 8.4 times greater odds of fluid clearance. Results from this study confirm that exercise and exercise combined with oxytocin are effective methods to clear intrauterine fluid.

Girthiness: Retrospective Study of 37 Horses (2004-2016).

Girth aversion or girthiness is a nonspecific clinical sign anecdotally associated with multiple conditions in the horse (behavioral problems, gastric ulcers, back pain); however, studies have not been conducted to definitively correlate this clinical sign to specific pathologies. This retrospective study aims to describe the clinical signs and final diagnoses of 37 horses evaluated at the University of California, Davis with a presenting complaint of girthiness. Medical records of all horses presented to the veterinary hospital between 2004 and 2016 for girthiness were reviewed. Twelve horses were diagnosed with gastric ulceration, 10 with various orthopedic problems, 3 with ill-fitting saddles, 1 with reproductive tract neoplasia, and 10 with various diseases including liver abscessation, vena cava aneurism, sternum pain, and urinary tract infection. Identifying the exact cause of girthiness remains a challenge; however, gastric ulcers was a common finding; therefore, a clinical examination should be oriented to further investigate this condition because 92% of gastroscoped horses in this study were diagnosed with gastric ulcers.