Cartilaginous airway wall dimensions and airway resistance in cystic fibrosis lungs

Abstract

It is not clear how airway pathology relates to the severity of airflow obstruction and increased bronchial responsiveness in cystic fibrosis (CF) patients. The aim of this study was to measure the airway dimensions of CF patients and to estimate the importance of these dimensions to airway resistance using a computational model.Airway dimensions were measured in lungs obtained from CF patients who had undergone lung transplantation (n=12), lobectomy (n=1), or autopsy (n=4). These dimensions were compared to those of airways from lobectomy specimens from 72 patients with various degrees of chronic obstructive pulmonary disease (COPD). The airway dimensions of the CF and COPD patients were introduced into a computational model to study their effect on airway resistance.The inner wall and smooth muscle areas of peripheral CF airways were increased 3.3-and 4.3-fold respectively compared to those of COPD airways. The epithelium was 53% greater in height in peripheral CF airways. The sensitivity and maximal plateau resistance of the computed dose/response curves were substantially increased in the CF patients compared to COPD patients.The changes in airway dimensions of cystic fibrosis patients probably contribute to the severe airflow obstruction, and to increased bronchial responsiveness, in these patients. Eur Respir J 2000; 15: 735±742.

Computed tomographic imaging of the airways: relationship to structure and function

“…The characteristic airway abnormalities are bronchiectasis, thickening of the airway wall and mucus plugging [97,103,107,[120][121][122][123][124][125][126], as shown in figure 5.…”

“…Airway disease in CF is characterised by mucus plugging, chronic infection and an excessive inflammatory response, leading to peripheral airway changes in the first few months of life [101][102][103][104][105][106][107][108][109][110][111][112][113][114][115][116][117][118][119]. The characteristic airway abnormalities are bronchiectasis, thickening of the airway wall and mucus plugging [97,103,107,[120][121][122][123][124][125][126], as shown in figure 5.…”

Tools used to measure airway remodelling in research

“…The structural alterations characterising the CF airways include goblet cell and submucosal gland extension to bronchioles and greater height of the epithelium. Loss of cartilage [55], excessive angiogenesis [56] and increased thickness of inner wall and smooth muscle areas in peripheral airways is also observed [57]. A dense fibrous deposition of collagens I and III, tenascin and elastin is reported in the bronchial wall [58].…”

Airways Clearance Techniques in Cystic Fibrosis: Physiology, Devices and the Future

“…(Tiddens HA, et al, 2000) Changes in the airway dimensions of CF patients compared to chronic obstructive lung disease (COPD) patients showed that, for airways of 1.9 mm diameter (12 th generation), there was an approximately fivefold increase in the smooth muscle area and a threefold increase in the inner wall area without epithelium. In the larger airways (35 mm diameter) there was a 1.5 increase in smooth muscle area with an almost identical inner wall area without epithelium.…”

“…(Goldman et al, 1997;Rosenstein & Zeitlin, 1998). Thus in CF, bacterial colonization and mucus hypersecretion occur as a consequence, leading to progressive lung damage (Tiddens et al, 2000) Fig. 8.…”