Particulate Oxidative Burden as a Predictor of Exhaled Nitric Oxide in Children with Asthma
BACKGROUND: Epidemiological studies have provided strong evidence that fine particulate matter (PM2.5, aerodynamic diameter 2.5µm and lower) can exacerbate asthmatic symptoms in children. Pro-oxidant components of PM2.5 are capable of directly generating reactive oxygen species. Oxidative burden is used to describe the capacity of PM2.5 to generate reactive oxygen species in the lung.
OBJECTIVE: This study investigated the association between airway inflammation in asthmatic children and oxidative burden of PM2.5 personal exposure.
METHODS: Daily PM2.5 personal exposure samples (n=249) of 62 asthmatic school-aged children in Montreal were collected over ten consecutive days. The oxidative burden of PM2.5 samples was determined in vitro as the depletion of low molecular weight antioxidants (ascorbate and glutathione) from a synthetic model of the fluid lining the respiratory tract. Airway inflammation was measured daily as fractional exhaled nitric oxide (FeNO).
RESULTS: A positive association was identified between FeNO and glutathione-related oxidative burden exposure in the previous 24 hours (6.0% increase per IQR change in glutathione). Glutathione-related oxidative burden was further found to be positively associated with FeNO over 1-day lag and 2-day lag periods. Results further demonstrate that corticosteroids use may reduce the FeNO response to elevated glutathione-related oxidative burden exposure (no use: 15.8%; irregular use: 3.8%), while mould (22.1%), dust (10.6%) or fur (13.1%) allergies may increase FeNO compared to children without these allergies (11.5%). No association was found between PM2.5 mass or ascorbate-related oxidative burden and FeNO levels.
CONCLUSIONS: Exposure to PM2.5 with elevated glutathione-related oxidative burden was associated with increased FeNO.
Publication titleEnvironmental Health Perspectives
Department/SchoolMenzies Institute for Medical Research
PublisherUS Department of Health and Human Services
Place of publicationUnited States
Rights statementPublic domain 'Reproduced with permission from Environmental Health Perspectives'