Assessment of airway smooth muscle hypertrophy in asthma and chronic obstructive pulmonary disease (COPD) [ 2007 - 2009 ]

Research Grant

Researchers: Prof Alan James (Principal investigator) ,  Neil Carroll

Brief description Asthma and chronic obstructive pulmonary disease (COPD) are common in the Australian community. The cause of asthma is unknown and although COPD is most often due to smoking cigarettes it remains unknown why it develops only in some smokers and in some non-smokers. The pathology of asthma and COPD includes increased thickness of the airway smooth muscle layer. In asthma this is associated with relatively normal airway lumen size and intermittent, excessive airway narrowing whereas in COPD it is associated with fixed narrowing of the airway lumens. The increased smooth muscle layer might result from more or bigger smooth muscle cells or from more connective tissue (matrix) between the muscle cells. This project aims to determine which of these 3 factors causes the increased thickness of the smooth muscle layer in asthma and COPD. We hypothesise that in asthma there are more muscle cells and more matrix, and that in COPD there is only more matrix. These differences would account for the different behaviour of the airways in asthma and COPD. Currently there is no useful or practical method to measure the amount of matrix in the airway wall, especially in the smooth muscle. This project will study the amount of matrix and muscle in very thin airway sections (< 1 m) from a large number of cases of asthma and COPD to allow, for the first time, accurate assessment of the fractions of matrix and muscle in the smooth muscle layer, since they barely overlap on these thin sections. The results of this study are important because they will: differentiate between mechanisms of increased thickness of the airway smooth muscle layer in asthma and COPD and therefore identify different prevention and treatment strategies; help to develop a method of monitoring airway remodeling in airway diseases that can be applied to bronchial biopsies.

Funding Amount $AUD 298,055.03

Funding Scheme NHMRC Project Grants

Notes Standard Project Grant