Inhaled histamine increases human lung mucociliary transport

Histamine, a mediator of airways constriction, alters ciliary beat frequency, bronchial mucus production, and epithelial ion transport; and in dogs, increases mucociliary transport. To evaluate the effect of inhaled histamine on human tracheobronchial mucociliary clearance, the authors measured lung mucociliary clearance (LMC) and tracheal mucociliary transport rate (TMTR) in 5 healthy, nonsmoking subjects in a randomized, double-blind, cross-over study. The concentration of inhaled histamine which produced a 20% fall in FEV1 was established for each subject. On a separate day the subjects inhaled a 9 μm MMAD /sup 99m/Tc-Fe2O3 aerosol. LMC and TMTR were then measured for 2.5h using a gamma camera and a tracheal multidetector probe. Simultaneously, the subjects were challenged every 26 +/- 4 min with either PBS or histamine in PBS. The Fe2O3 retained after 24h for histamine (14.4 +/- 7.6%) and PBS studies (13.1 +/- 8.6%) indicated no difference in deposition of Fe2O3 (ANOVA). Fe2O3 clearance at 30 min was increased in the histamine studies (61 +/- 21% compared to the PBS studies (44 +/- 29%; p < 0.02, ANOVA)). TMTR was also increased with histamine (7.6 +/- 3.4 mm/min) compared to PBS (4.6 +/- 1.7 mm/min; p < 0.001, ANOVA). Results indicate an acute stimulatory effect of inhaled histamine on mucous transport in humans