SELECTED ARTICLES FROM THE RECENT LITERATURE 2005

11/9/05

Formoterol effects on neutrophilic inflammation

Summary
Background - The addition of inhaled long acting beta agonists (LABA) such as formoterol (Form) to low dose inhaled corticosteroids (ICS) enhances the clinical efficacy of the ICS treatment in persistent asthma. The mechanism underlying this beneficial effect of LABA has not been well-defined. Questions have been raised whether LABA such as Form have independent anti-inflammatory effects.

Findings - Maneechotesuwan et al of the National Heart and Lung Institute in London, UK carried out a double blind, randomized, crossover study of the effects of inhaled Form, 24 microg vs placebo used b.i.d. for 4 weeks in 15 mild asthmatic patients who had not been receiving ICS therapy. They found significantly reduced neutrophil frequency and IL-8 levels in the sputum after Form treatment than after placebo treatment. There was a significant correlation between the reduction in IL-8 levels and neutrophil frequency.

Reference
 Chest 2005;128:1936-42

Editor's Comments
These findings are of interest but several questions can be raised about them: 1) as the authors state, increased neutrophil frequency is generally present in the sputum of severe asthmatics, not the mild (ICS-naive) asthmatics studied here; 2) the authors postulate that decreased local IL-8 secretion is responsible for the decreased neutrophilia, but show no direct evidence for such decreased synthesis; 3) a recent study found no additive effect of Form treatment (when added to ICS therapy for 12 weeks) in reducing sputum eosinophilia in asthmatics (Chest 2005;128:121-27). The ICS plus Form treatment for 12 weeks in the latter study is more relevant to the usual chronic use of Form in management of persistent asthma.

 

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