Nebulized lidocaine blunts airway hyper-responsiveness in experimental feline asthma

Abstract

Nebulized lidocaine may be a corticosteroid-sparing drug in human asthmatics, reducing airway resistance and peripheral blood eosinophilia. We hypothesized that inhaled lidocaine would be safe in healthy and experimentally asthmatic cats, diminishing airflow limitation and eosinophilic airway inflammation in the latter population. Healthy (n = 5) and experimentally asthmatic (n = 9) research cats were administered 2 weeks of nebulized lidocaine (2 mg/kg q8h) or placebo (saline) followed by a 2-week washout and crossover to the alternate treatment. Cats were anesthetized to measure the response to inhaled methacholine (MCh) after each treatment. Placebo and doubling doses of methacholine (0.0625-32.0000 mg/ml) were delivered and results were expressed as the concentration of MCh increasing baseline airway resistance by 200% (EC200Raw). Bronchoalveolar lavage was performed after each treatment and eosinophil numbers quantified. Bronchoalveolar lavage fluid (BALF) % eosinophils and EC200Raw within groups after each treatment were compared using a paired t-test (P <0.05 significant). No adverse effects were noted. In healthy cats, lidocaine did not significantly alter BALF eosinophilia or the EC200Raw. There was no difference in %BALF eosinophils in asthmatic cats treated with lidocaine (36±10%) or placebo (33 ± 6%). However, lidocaine increased the EC200Raw compared with placebo 10 ± 2 versus 5 ± 1 mg/ml; P = 0.043). Chronic nebulized lidocaine was well-tolerated in all cats, and lidocaine did not induce airway inflammation or airway hyper-responsiveness in healthy cats. Lidocaine decreased airway response to MCh in asthmatic cats without reducing airway eosinophilia, making it unsuitable for monotherapy. However, lidocaine may serve as a novel adjunctive therapy in feline asthmatics with beneficial effects on airflow obstruction.

Intravenous adipose-derived mesenchymal stem cell therapy for the treatment of feline asthma: a pilot study

“…Ventilator-acquired pulmonary mechanics were performed on day 133 as previously described, 19 with minor modifications. Cats were premedicated with ketamine (30 mg IV).…”

Long‐term evaluation of mesenchymal stem cell therapy in a feline model of chronic allergic asthma

“…Cats were intubated with identical (internal diameter 4 mm, length 14 cm) cuffed endotracheal tubes to standardize the effect of the endotracheal tube on airway resistance. Mechanical ventilation was performed as previously described . The maximum allowable peak airway pressure was set at 50 cmH 2 0.…”

Dexamethasone and lidocaine suppress eosinophilopoiesis from umbilical cord blood cells

“…Lidocaine and its analogue also affect the activity and survival of mature eosinophils [15] and inhibit allergen-induced eosinophilic inflammation [16][17][18]. Conversely, some studies report that they do not affect airway eosinophilia [19,20]. Thus, there is no definitive answer to the nature of the effect of steroids on eosinophilopoiesis and no direct study on the effect of lidocaine on eosinophilopoiesis.…”