Relationship between pulmonary matrix metalloproteinases and quantitative CT markers of small airways disease and emphysema in COPD

Thorax. 2016 Feb;71(2):126-32. doi: 10.1136/thoraxjnl-2015-207428. Epub 2015 Dec 8.


Background: Matrix metalloproteinases (MMPs) are proteolytic enzymes that can degrade the extracellular matrix and drive tissue remodelling, key processes in the pathogenesis of COPD. The development of small airway disease has been identified as a critical mechanism in the early development of airflow obstruction but the contribution of MMPs in human disease is poorly characterised.

Objectives: We investigated the role of MMPs and inflammatory cytokines in the lung by quantifying levels and determining relationships with the key pathological components of COPD in patients and healthy controls.

Methods: We analysed levels of MMPs and inflammatory cytokines in bronchoalveolar lavage from 24 COPD and 8 control subjects. Each subject underwent spirometry and high-resolution CT. Image analysis quantitatively assessed emphysema, bronchial wall thickening and small airways disease.

Results: Multiple MMPs (MMP-1, -2, -3, -8, -9 and -10) and cytokines (interleukin (IL) 6 and IL-8) were elevated in lungs of subjects with COPD. MMP-3, -7, -8, -9, -10 and -12 concentrations closely associated with CT markers of small airways disease. Emphysema severity was also associated with MMP-3, -7 and -10. However, there were no strong relationships between MMPs and bronchial wall thickness of the larger airways.

Conclusions: Pulmonary MMP concentrations are directly associated with the extent of gas trapping and small airways disease identified on CT scan. This study suggests that MMPs play a significant role in small airways remodelling, a key feature in the pathogenesis of COPD.

Trial registration number: NCT01701869.

Keywords: COPD ÀÜ Mechanisms; Emphysema; Imaging/CT MRI etc; Lung Proteases.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Biomarkers / metabolism*
  • Bronchi / metabolism*
  • Bronchi / pathology
  • Bronchoalveolar Lavage Fluid / chemistry*
  • Bronchoscopy
  • Cytokines / metabolism
  • Female
  • Humans
  • Male
  • Matrix Metalloproteinases / metabolism*
  • Middle Aged
  • Pulmonary Disease, Chronic Obstructive / complications
  • Pulmonary Disease, Chronic Obstructive / diagnostic imaging
  • Pulmonary Disease, Chronic Obstructive / metabolism*
  • Pulmonary Emphysema / diagnostic imaging
  • Pulmonary Emphysema / etiology
  • Pulmonary Emphysema / metabolism*
  • Spirometry
  • Tomography, X-Ray Computed*


  • Biomarkers
  • Cytokines
  • Matrix Metalloproteinases

Associated data