Repeated Nitrogen Dioxide Exposures and Eosinophilic Airway Inflammation in Asthmatics: A Randomized Crossover Study.

Autor:	Ezratty, VéRonique¹ veronique.ezratty@edf.fr, Guillossou, Gaëlle¹, Neukirch, Catherine², Dehoux, Monique³, Koscielny, Serge⁴, Bonay, Marcel⁵, Cabanes, Pierre-André¹, Samet, Jonathan M.⁶, Mure, Patrick⁷, Ropert, Luc⁷, Tokarek, Sandra⁷, Lambrozo, Jacques¹, Aubier, Michel²
Předmět:	Asthma Nitrogen oxides Eosinophilic esophagitis Confidence intervals Research funding Data analysis software Descriptive statistics Odds ratio Disease complications Disease risk factors
Zdroj:	Environmental Health Perspectives. Aug2014, Vol. 122 Issue 8, p850-855. 6p. 2 Diagrams, 3 Charts.
Abstrakt:	Background: Nitrogen dioxide (NO2), a ubiquitous atmospheric pollutant, may enhance the asthmatic response to allergens through eosinophilic activation in the airways. However, the effect of NO2 on inflammation without allergen exposure is poorly studied. Objectives: We investigated whether repeated peaks of NO2, at various realistic concentrations, induce changes in airway inflammation in asthmatics. Methods: Nineteen nonsmokers with asthma were exposed at rest in a double-blind, crossover study, in randomized order, to 200 ppb NO2, 600 ppb NO2, or clean air once for 30 min on day 1 and twice for 30 min on day 2. The three series of exposures were separated by 2 weeks. The inflammatory response in sputum was measured 6 hr (day 1), 32 hr (day 2), and 48 hr (day 3) after the first exposure, and compared with baseline values measured twice 10–30 days before the first exposure. Results: Compared with baseline measurements, the percentage of eosinophils in sputum increased by 57% after exposure to 600 ppb NO2 (p = 0.003) but did not change significantly after exposure to 200 ppb. The slope of the association between the percentage of eosinophils and NO2 exposure level was significant (p = 0.04). Eosinophil cationic protein in sputum was highly correlated with eosinophil count and increased significantly after exposure to 600 ppb NO2 (p = 0.001). Lung function, which was assessed daily, was not affected by NO2 exposure. Conclusions: We observed that repeated peak exposures of NO2 performed without allergen exposure were associated with airway eosinophilic inflammation in asthmatics in a dose-related manner. [ABSTRACT FROM AUTHOR]
Databáze:	GreenFILE
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