Protective effects of inhaled PGE2 on allergen-induced airway responses and airway inflammation.
Inhalation of prostaglandin E2 (PGE2) had been reported to prevent allergen-induced bronchoconstrictor responses; however, the effects of inhaled PGE2 on allergen-induced airway inflammation or hyperresponsiveness after allergen are unknown. This study examined the effects of inhaled PGE2 on allergen-induced airway responses and inflammation. Eight mild asthmatics with a dual airway response to inhaled allergen were recruited into a double-blind randomized crossover study comparing the effects of inhaled PGE2 (100 microgram) or placebo, on allergen-induced changes in FEV1 measured for 7 h, induced sputum inflammatory cells, obtained at baseline, 7 and 24 h, and methacholine airway responsiveness measured at 24 h after challenge. Inhaled PGE2 attenuated the allergen-induced early fall in FEV1 from 24.4 +/- 3.6% after placebo to 10.3 +/- 2.5% after PGE2 (p = 0.002), the late fall in FEV1 from 21.2 +/- 2.7% after placebo to 12.6 +/- 3.6% after PGE2 (p = 0.03), allergen-induced methacholine airway hyperresponsiveness (p = 0.03) and allergen-induced increases in percent sputum eosinophils from 36.3 +/- 8.8% after placebo to 21.0 +/- 7.3% after PGE2 (p = 0.01), percentage of EG2+ cells (p = 0.02), and percentage of metachromatic cells (p = 0.02). These results indicate that inhaled PGE2 attenuates allergen-induced airway responses, hyperresponsiveness, and inflammation, when given immediately before inhaled allergen.
Gauvreau
G M
GM
Asthma Research Group, Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
Watson
R M
RM
O'Byrne
P M
PM
D000280:Administration, Inhalation; D000328:Adult; D000485:Allergens / Q000276:immunology*; D001249:Asthma / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology*; D016085:Bronchoconstrictor Agents; D002452:Cell Count / Q000187:drug effects; D018592:Cross-Over Studies; D015232:Dinoprostone / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects; D006801:Humans; D008297:Male; D016210:Methacholine Chloride; D013183:Sputum / Q000166:cytology / Q000187:drug effects
D000485:Allergens; D016085:Bronchoconstrictor Agents; D016210:Methacholine Chloride; D015232:Dinoprostone