SELECTED ARTICLES FROM THE RECENT LITERATURE 2004

11/8/04

Effects of inhaled corticosteroids on exhaled leukotrienes and prostanoids in asthmatic children

Summary
Background - Lipid mediators such as leukotrienes and prostanoids are considered to play pathogenic roles in childhood atopic asthma. However, it is not known whether such mediators play roles in atopics with rhinitis but no asthma. The effects of inhaled corticosteroids (ICS) on such mediators is also unclear.

Findings - Mondino et al of the Catholic Univ of Sacred Heart in Rome, Italy compared the levels of several inflammatory mediators in the exhaled breath condensate from: 1) atopic asthmatics; 2) atopic non-asthmatics; 3) normal age-matched pediatric normal controls. They found increased levels of leukotriene E4 (LTE4) and B4 (LTB4) as well as 8-isoprostane in the exhaled breath condensate of atopic asthmatics but not of atopic non-asthmatics. Of note, the levels of these mediators in atopic asthmatics was not affected by current ICS therapy. Levels of exhaled nitric oxide (NO), another marker of bronchial inflammation, were increased in atopic asthmatics and to a lesser extent in atopic non-asthmatics. These NO levels decreased significantly following ICS therapy. Levels of exhaled LTB4, prostaglandin E2 and 8 isoprostane were not affected by this ICS therapy.

Conclusions - Exhaled levels of LTE4, LTB4 and 8-isoprostane are increased in allergic asthmatics but not in non-asthmatics. These increased mediator levels are not decreased by ICS therapy.

Reference
J Allergy Clin Immunol 2004; 114:761-7

Editor's Comments
It is now generally recognized that persistent asthma is likely heterogeneous in both pathogenesis and clinical presentation. Leukotrienes and prostanoids may play pathogenic roles to varying degrees in some, but not other, asthmatics. This could be one explanation for the variable clinical response to a selective leukotriene antagonist drugs in different asthmatics. Exhaled NO may be more a marker of atopic inflammation with or without asthma

 

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