UCLA

Children are considered to be highly susceptible to the adverse effects of pollutants such as diesel exhaust particles (DEP). Phase II enzymes are a key defense against the oxidant effects of pollutants. Twenty adults and fifteen children (11-16 years of age) underwent a single-blind placebo controlled randomized exposure study to differing DEP nasal challenges. Gene expression levels of 3 sentinel Phase II genes (GSTP1, NQO1, HO-1) and markers of inflammation were measured before and 24 hours after DEP challenge. We found that nasal lavage cell count increased with increasing DEP challenge doses in adults and children. However, at the highest doses children had greater cellular inflammation and decreased Phase II enzyme expression as compared to adults. Children appear to have a diminished ability to generate protective enzymes in response to higher DEP exposures as compared to adults. Impaired antioxidant defenses in children may lead to increased vulnerability to pollution-induced airway diseases.