Reflux aspiration in lungs of dogs with respiratory disease and in healthy West Highland White Terriers.

BACKGROUND: Gastroesophageal reflux and microaspiration (MA) of gastric juice are associated with various human respiratory diseases but not in dogs. OBJECTIVE: To detect the presence of bile acids in bronchoalveolar lavage fluid (BALF) of dogs with various respiratory diseases. ANIMALS: Twenty-seven West Highland White Terriers (WHWTs) with canine idiopathic pulmonary fibrosis (CIPF), 11 dogs with bacterial pneumonia (BP), 13 with chronic bronchitis (CB), 9 with eosinophilic bronchopneumopathy (EBP), 19 with laryngeal dysfunction (LD), 8 Irish Wolfhounds (IWHs) with previous BPs, 13 healthy WHWTs, all privately owned dogs, and 6 healthy research colony Beagles METHODS: Prospective cross-sectional observational study with convenience sampling of dogs. Bile acids were measured by mass spectrometry in BALF samples. Total bile acid (TBA) concentration was calculated as a sum of 17 different bile acids. RESULTS: Concentrations of TBA were above the limit of quantification in 78% of CIPF, 45% of BP, 62% of CB, 44% of EBP, 68% of LD, and 13% of IWH dogs. In healthy dogs, bile acids were detected less commonly in Beagles (0/6) than in healthy WHWTs (10/13). Concentrations of TBA were significantly higher in CIPF (median 0.013 µM, range not quantifiable [n.q.]-0.14 µM, P < .001), healthy WHWTs (0.0052 µM, n.q.-1.2 µM, P = .003), LD (0.010 µM, n.q.-2.3 µM, P = .015), and CB (0.0078 µM, n.q.-0.073 µM, P = .018) groups compared to Beagles (0 µM, n.q.). CONCLUSION AND CLINICAL IMPORTANCE: These results suggest that MA occurs in various respiratory diseases of dogs and also in healthy WHWTs.

Endocrine effects of inhaled budesonide compared with inhaled fluticasone propionate and oral prednisolone in healthy Beagle dogs.

Orally administered corticosteroids are commonly used to treat chronic respiratory disease, but adverse effects suggest that the inhalation route may be safer. To compare the systemic effects of inhaled and oral corticosteroids, a prospective, randomised, placebo-controlled cross-over study was conducted. Six healthy neutered female Beagle dogs were randomly allocated to four treatment groups: (1) budesonide inhalation (200 µg twice daily); (2) fluticasone inhalation (250 µg twice daily); (3) oral prednisolone (1mg/kg once daily); and (4) placebo inhalation (room air twice daily). Each treatment and wash-out period lasted 4 weeks. The endocrine status of each dog was assessed on days 0, 28 and 35 using the adrenocorticotropic hormone (ACTH) stimulation test. The effects of treatments were assessed using a linear mixed effects model. After the 4 week treatment period, a significant decrease was observed in the basal serum cortisol level of the prednisolone group (P<0.03), and a decrease was also seen in the ACTH-stimulated peak cortisol levels of both the prednisolone and fluticasone groups (P<0.001), compared with the budesonide group in which no suppression was detected. The results showed that cortisol production in dogs was strongly suppressed by oral prednisolone and by inhaled fluticasone.

Liquid chromatography tandem mass spectrometry determination of total budesonide levels in dog plasma after inhalation exposure.

A sensitive and selective method to quantify budesonide in dog plasma samples was developed and fully validated. Liquid-liquid extraction was followed by solid-phase extraction and liquid chromatography-tandem mass spectrometry with electrospray ionization. After reconstitution of the analytes in the mobile phase, samples were analysed by reversed-phase liquid chromatography with isocratic elution. d8-Budesonide was used as an internal standard, and characteristic transitions of d8-budesonide and budesonide were used for quantification. The method was validated with respect to selectivity, specificity, linearity, recovery, repeatability, reproducibility and limits of detection and quantification. The validated method was successfully applied to monitor the plasma levels of budesonide in dogs exposed to clinical doses of inhaled and intravenous drug.

Comparison of results for weight-adjusted and fixed-amount bronchoalveolar lavage techniques in healthy Beagles.

OBJECTIVE: To compare recovery of epithelial lining fluid (ELF) in bronchoalveolar lavage fluid (BALF) by use of weight-adjusted or fixed-amount volumes of lavage fluid in dogs. ANIMALS: 13 healthy Beagles. PROCEDURES: Dogs were allocated to 2 groups. In 1 group, the right caudal lung lobe was lavaged on the basis of each dog's weight (2 mL/kg, divided into 2 aliquots) and the left caudal lung lobe was lavaged with a fixed amount of fluid (50 mL/dog, divided into 2 aliquots). In the second group, the right and left caudal lung lobes were lavaged by use of the fixed-amount and weight-adjusted techniques, respectively. The BALF was collected by use of bronchoscopy. A recovery percentage ≥ 40% was required. The proportion of ELF was calculated by use of the following equation: (concentration of urea in BALF/concentration of urea in serum) × 100. RESULTS: Mean ± SD proportion of ELF in BALF was 2.28 ± 0.39% for the weight-adjusted technique and 2.89 ± 0.89% for the fixed-amount technique. The SDs between these 2 techniques differed significantly (calculated by comparing 2 covariance structures [unstructured and compound symmetry] in a repeated-measures mixed ANOVA). CONCLUSIONS AND CLINICAL RELEVANCE: The findings strongly suggested that use of a weight-adjusted bronchoalveolar lavage technique provided a more uniform ELF recovery, compared with that for a fixed-amount bronchoalveolar lavage technique, when urea was used as a marker of dilution. A constant ELF fraction can facilitate more accurate comparisons of cellular and noncellular constituents in BALF among patients of various sizes.