The Effect of Glucocorticoids on Grain Dust-Induced Airway Disease

¹ From the Pulmonary Diseases, Critical Care, and Occupational Medicine Division, Department of Internal Medicine, The University of Iowa College of Medicine, Iowa City

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- 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.

Key Words: airway injury • asthma • glucocorticoids • grain dust

Submitted on June 25, 1997
Accepted on August 25, 1000

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