Small airway morphology and lung function in the transition from normality to chronic airway obstruction

• Published in: Journal of applied physiology (1985) Vol. 95; no. 1; pp. 441 - 447
• Main Authors: Corsico, Angelo, Milanese, Manlio, Baraldo, Simonetta, Casoni, Gian Luca, Papi, Alberto, Riccio, Anna Maria, Cerveri, Isa, Saetta, Marina, Brusasco, Vito
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Am Physiological Soc 01.07.2003; American Physiological Society
• Subjects: Aged; Air breathing; Biological and medical sciences; Bronchi - pathology; Bronchi - physiopathology; Bronchial Hyperreactivity - metabolism; Bronchial Hyperreactivity - physiopathology; Female; Forced Expiratory Volume - physiology; Fundamental and applied biological sciences. Psychology; Humans; Lung - pathology; Lung - physiopathology; Male; Methacholine Chloride - pharmacology; Muscarinic Agonists - pharmacology; Pulmonary Disease, Chronic Obstructive - pathology; Pulmonary Disease, Chronic Obstructive - physiopathology; Respiratory Mechanics - physiology; Respiratory system: anatomy, metabolism, gas exchange, ventilatory mechanics, respiratory hemodynamics; Vertebrates: respiratory system; Vital Capacity - physiology; airway hyperresponsiveness; Correlation; Wall; Closure; Hyperreactivity; Pathophysiology; airway closure; Respiratory system; Respiratory tract; Vertebrata; Lung function; Mammalia; interdependence; Morphology; deep inhalation; smoking; Thickening
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.01018.2002

2 Dipartimento di Medicina Interna, Università di Genova, 16132 Genova; 1 Clinica di Malattie dell'Apparato Respiratorio, IRCCS Policlinico S. Matteo, Università di Pavia, 27100 Pavia; 3 Dipartimento di Medicina Clinica e Sperimentale, Sezione di Malattie dell'Apparato Respiratorio, Università di Padova, 35128 Padova; and 4 Centro di Ricerca per l'Asma e la BPCO, Università di Ferrara, 44100 Ferrara, Italy Submitted 5 November 2002 ; accepted in final form 10 February 2003 This study investigated the relationships between pathological changes in small airways (<6 mm perimeter) and lung function in 22 nonasthmatic subjects (20 smokers) undergoing lung resection for peripheral lesions. Preoperative pulmonary function tests revealed airway obstruction [ratio of forced expiratory volume in 1 s to forced vital capacity (FEV 1 /FVC) < 70%] in 12 subjects and normal lung function in 10. When all subjects were considered together, total airway wall thickness was significantly correlated with FEV 1 /FVC ( r 2 = 0.25), reactivity to methacholine ( r 2 = 0.26), and slope of linear regression of FVC against FEV 1 values recorded during the methacholine challenge ( r 2 = 0.56). Loss of peribronchiolar alveolar attachments was significantly associated ( r 2 = 0.25) with a bronchoconstrictor effect of deep inhalation, as assessed from a maximal-to-partial expiratory flow ratio <1, but not with airway responses to methacholine. No significant correlation was found between airway smooth muscle thickness and lung function measurements. In conclusion, this study suggests that thickening of the airway wall is a major mechanism for airway closure, whereas loss of airway-to-lung interdependence may contribute to the bronchoconstrictor effect of deep inhalation in the transition from normal lung function to airway obstruction in nonasthmatic smokers. smoking; airway hyperresponsiveness; airway closure; deep inhalation; interdependence Address for reprint requests and other correspondence: V. Brusasco, Dipartimento di Medicina Interna, Viale Benedetto XV, 6, 16132 Genova, Italy (E-mail: vito.brusasco{at}unige.it ).