CARTILAGINOUS AIRWAY DIMENSIONS AND AIR-FLOW OBSTRUCTION IN HUMAN LUNGS

Airway wall remodeling in asthma and chronic obstructive pulmonary dis ease (COPD) can have a profound effect on the function of the airways. We tested the hypothesis that airflow obstruction and estimates of pe ripheral airway inflammation correlate with airway wall thickness and the amount of bronchial smooth muscle in cartilaginous airways. In add ition, we estimated the theoretical relation between airway dimensions and airway resistance with a computational model. Lung tissue was obt ained from 72 patients with different degrees of COPD who were operate d on for a solitary peripheral lung lesion. In 341 transversely cut ca rtilaginous airway sections we measured airway size and airway wall di mensions. Inflammatory changes from the same lungs were scored in nonc artilaginous airways. Pre-operatively measured maximum expiratory flow s and the response to a bronchodilator were correlated with airway wal l dimensions. Maximum expiratory flow, the reversibility of airflow ob struction, and peripheral airway inflammation were significantly relat ed to the airway wall area but not to the smooth muscle area. We concl ude that airflow obstruction and its reversibility in COPD is in part caused by thickening of the cartilaginous airway wall and is related t o inflammatory changes.