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Enantiomer-Specific Effects of Albuterol on Airway Inflammation in Healthy and Asthmatic Cats

2009; Karger Publishers; Volume: 150; Issue: 1 Linguagem: Inglês

10.1159/000210379

1423-0097

Carol R. Reinero, Cherlene Delgado, Christine Spinka, Amy E. DeClue, Rajiv Dhand,

Neuropeptides and Animal Physiology

<i>Background:</i> Racemic (<i>R</i>,<i>S</i>)-albuterol is a 1:1 mixture of an <i>R</i>-enantiomer which has bronchodilatory and anti-inflammatory effects, and an <i>S</i>-enantiomer which is associated with increased airway hyperreactivity and proinflammatory effects. Proinflammatory effects of regularly inhalated and <i>S</i>-albuterol have not been studied in a whole-animal model. We hypothesized that regular administration of <i>R</i>,<i>S</i>-albuterol or <i>S</i>-albuterol, but not <i>R</i>-albuterol, would induce airway inflammation in healthy and asthmatic cats. <i>Methods:</i> Six healthy and 5 experimentally asthmatic cats were randomized to receive inhaled <i>R</i>,<i>S</i>-albuterol, <i>S</i>-albuterol, <i>R</i>-albuterol, or placebo (saline) twice daily for 2 weeks, followed by a 6-week washout before crossover to the next treatment. Bronchoalveolar lavage fluid was collected for cell counts and cytokine analysis prior to and at the end of each 2-week treatment. <i>Results:</i> Healthy and asthmatic cats receiving <i>R</i>,<i>S</i>- and <i>S</i>-albuterol had higher total lavage cell numbers (p = 0.04 and p = 0.02, respectively) than those receiving <i>R</i>-albuterol and placebo. The number of lavage eosinophils and the TNF-α bioactivity was higher in asthmatic cats receiving <i>R</i>,<i>S</i>- and <i>S</i>-albuterol compared with those receiving the other treatments (p = 0.03 and p = 0.004, respectively). In healthy cats, the number of lavage neutrophils was higher when they received <i>R</i>,<i>S</i>- and <i>S</i>-albuterol compared with other treatments (p = 0.04). <i>Conclusion:</i> Airway inflammation is induced in both healthy and asthmatic cats with regular inhalation of racemic and <i>S</i>-albuterol, but not with <i>R</i>-albuterol.