Repeated nitrogen dioxide exposures and eosinophilic airway inflammation in asthmatics: a randomized crossover study.
Environ Health Perspect
; 122(8): 850-5, 2014 Aug.
Article
em En
| MEDLINE
| ID: mdl-24747297
ABSTRACT
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.
Texto completo:
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Base de dados:
MEDLINE
Assunto principal:
Asma
/
Alérgenos
/
Eosinófilos
/
Inflamação
/
Dióxido de Nitrogênio
Tipo de estudo:
Clinical_trials
Limite:
Adult
/
Female
/
Humans
/
Male
Idioma:
En
Revista:
Environ Health Perspect
Ano de publicação:
2014
Tipo de documento:
Article
País de afiliação:
França