Study objectives: To determine the effect of glucocorticoids on grain dust-induced airflow obstruction and airway inflammation.
Design: Randomized controlled trial.
Setting: University hospital.
Participants: Health volunteers.
Interventions: Two randomized, placebo-controlled trials, each studying 10 healthy volunteers who were pretreated with either triamcinolone acetonide (Azmacort) oral inhaler 4 puffs twice daily (800 µg daily) for 7 consecutive days or IV hydrocortisone (3 µg/kg/min) as a 14-h continuous infusion, then subjected to a controlled inhalation exposure to corn dust extract (CDE) (endotoxin exposure dose of 3 µg/kg). A single-blind, crossover study design was performed for each trial enrolling 10 healthy, lifetime nonsmokers, with no history of lung disease or environmental exposure to grain dust.
Measurements and results: Following each inhalation exposure to CDE, spirometry was performed at regular intervals and BAL was performed at 4 h. Both treatment and placebo groups demonstrated significant decrements in spirometry and increments in BAL cellularity following CDE inhalation compared with placebo. Inhaled steroid treatment resulted in a significantly higher FEV1 only at the 2-h time point following CDE inhalation with no significant differences observed in the BAL total cell concentration or cellular differential compared with placebo. IV hydrocortisone treatment resulted in a significantly higher FEV1 and FVC between 2 and 4 h after CDE inhalation, as well as significant reductions in the BAL total cell, macrophage, and eosinophil concentrations. Interestingly, the concentration of tumor necrosis factor-α and interleukin-8 in the BAL fluid was also decreased following treatment with IV glucocorticoids.
Conclusions: These results demonstrate that glucocorticoids, administered IV and perhaps by inhalation, have a mildly protective effect on airflow obstruction and airway inflammation induced by inhalation of grain dust.