Edited by: Michael Wechsler
Extracellular matrix in airway smooth muscle is associated with dynamics of airway function in asthma
Article first published online: 9 JAN 2012
© 2012 John Wiley & Sons A/S
Volume 67, Issue 4, pages 552–559, April 2012
How to Cite
- Issue published online: 13 MAR 2012
- Article first published online: 9 JAN 2012
- Manuscript Accepted: 26 NOV 2011
- extracellular matrix;
- respiratory function tests;
- smooth muscle.
Altered deposition of extracellular matrix (ECM) in the airway smooth muscle (ASM) layer as observed in asthma may influence ASM mechanical properties. We hypothesized that ECM in ASM is associated with airway function in asthma. First, we investigated the difference in ECM expression in ASM between asthma and controls. Second, we examined whether ECM expression is associated with bronchoconstriction and bronchodilation in vivo.
Our cross-sectional study comprised 19 atopic mild asthma patients, 15 atopic and 12 nonatopic healthy subjects. Spirometry, methacholine responsiveness, deep-breath-induced bronchodilation (ΔRrs) and bronchoscopy with endobronchial biopsies were performed. Positive staining of elastin, collagen I, III and IV, decorin, versican, fibronectin, laminin and tenascin in ASM was quantified as fractional area and mean density. Data were analysed using Pearson's or Spearman's correlation coefficient.
Extracellular matrix expression in ASM was not different between asthma and controls. In asthmatics, fractional area and mean density of collagen I and III were correlated with methacholine dose–response slope and ΔRrs, respectively (r = 0.71, P < 0.01; r = 0.60, P = 0.02). Furthermore, ASM collagen III and laminin in asthma were correlated with FEV1 reversibility (r = −0.65, P = 0.01; r = −0.54, P = 0.04).
In asthma, ECM in ASM is related to the dynamics of airway function in the absence of differences in ECM expression between asthma and controls. This indicates that the ASM layer in its full composition is a major structural component in determining variable airways obstruction in asthma.