Genes and Pathways Regulating Decline in Lung Function and Airway Remodeling in Asthma

Hur, Gyu Young; Broide, David H.

MMPs are involved in extracellular matrix turnover and tissue repair. Studies in asthma have particularly focused on the role of MMP-9 (gelatinase B) in airway remodeling, 56 as it plays a key role in extracellular matrix turnover. Additional support for MMP-9 playing a role in asthma are derived from studies demonstrating that in asthma, the levels of MMP-9 are elevated 57 in blood, sputum, BAL and exhaled breath condensates from patients with asthma exacerbations. MMP-9-deficient mice have slightly less peribronchial fibrosis and total lung collagen compared to wild type mice. 58 However, MMP-9 deficient mice still have mucus hypersecretion, smooth muscle thickness and AHR, suggesting that in mice many of the features of airway remodeling are not controlled by MMP-9. 58 At present, there are no studies of SNPs in MMP-9 and their effect on decline in lung function or airway remodeling in asthma.