title: Respiratory epithelial permeability is unrelated to bronchial reactivity and small airway function in young smokers and nonsmokers.
abstract: We studied eight young smokers and ten nonsmokers, to determine whether respiratory epithelial permeability to radiolabelled diethylenetriamine penta-acetate (99mTcDTPA) was related to small airway function or bronchial reactivity. Permeability was measured in inner (containing central airways) and outer lung zones by gamma camera. Lung-to-blood half-time (LB-T1/2) was corrected for blood background. Histamine was inhaled tidally (2 min inhalations) using doubling concentrations from 2 to 64 mg.ml-1. Results of small airway function tests, and of bronchial reactivity (expressed as the threshold concentration (reducing forced expiratory volume in one second (FEV1) by 2 SD), and as the percentage reduction in FEV1 after histamine 16 mg.ml-1) were similar in smokers and nonsmokers. LB-T1/2 was shorter in smokers than in nonsmokers in both inner (median (range) 21 (5.5-33) vs 63.5 (41-115) min; p less than 0.004) and outer (20.5 (5.5-30) vs 58.5 (39-105) min; p less than 0.004) zones. Neither inner nor outer zone LB-T1/2 was related to small airway function or bronchial reactivity. Bronchial reactivity and small airway tests may be abnormal in middle-aged smokers, but neither is related to the increased respiratory epithelial permeability of young smokers, in whom it appears too sensitive an index of airway integrity.
authors.affiliation: Department of Thoracic Medicine, Royal Free Hospital, London.
authors.forename: R G
authors.initials: RG
authors.lastname: Taylor
authors.forename: J E
authors.initials: JE
authors.lastname: Agnew
authors.forename: R A
authors.initials: RA
authors.lastname: Francis
authors.forename: D
authors.initials: D
authors.lastname: Pavia
authors.forename: S W
authors.initials: SW
authors.lastname: Clarke
mesh_terms: D000328:Adult; D000403:Airway Resistance; D001980:Bronchi / Q000502:physiology*; D001985:Bronchial Provocation Tests; D006801:Humans; D008168:Lung / Q000502:physiology*; D008297:Male; D009942:Organometallic Compounds; D004369:Pentetic Acid; D011659:Pulmonary Gas Exchange; D012123:Pulmonary Ventilation; D012907:Smoking / Q000503:physiopathology*; D013667:Technetium; D016284:Technetium Tc 99m Pentetate
chemical_list: D009942:Organometallic Compounds; D013667:Technetium; D004369:Pentetic Acid; D016284:Technetium Tc 99m Pentetate