Variability in the precursor proteins of collagen I and III in different stages of COPD

Respir Res. 2010 Nov 30;11(1):165. doi: 10.1186/1465-9921-11-165.


Background: Levels of precursor proteins of collagen I and III are increased in fibrotic pulmonary diseases. This study determined whether the expression of precursors of type I and III collagen proteins would be increased in small and large airways of COPD patients in various stages of the disease reflecting fibrogenesis.

Methods: The levels of precursor proteins of collagen I and III were studied by immunohistochemistry and quantified by image analysis in lung tissue of 16 non-smokers, 20 smokers with normal lung function, 20 smokers with stage I-II COPD and 8 ex-smokers with stage IV COPD.

Results: In large airways, the subepithelial layer which was positive for precursor proteins of collagen I and III was thicker in smokers and in stage I-II COPD compared to non-smokers. Large airways in stage IV COPD showed reduced expression of precursor protein of collagen I whereas precursor of collagen III was increased. The amount of precursor protein of collagen III was increased in small airways of smokers and stage I-II COPD but reduced in stage IV COPD.

Conclusions: Precursor proteins of collagen I and III revealed different expression profiles in large and small airways in various stages of COPD. Smoking enhanced expression of both precursors in large airways with a positive correlation with pack-years.

MeSH terms

  • Aged
  • Collagen Type I / metabolism*
  • Collagen Type III / metabolism*
  • Disease Progression
  • Female
  • Humans
  • Lung / metabolism*
  • Male
  • Middle Aged
  • Pulmonary Disease, Chronic Obstructive / complications
  • Pulmonary Disease, Chronic Obstructive / metabolism*
  • Sensitivity and Specificity
  • Smoking / metabolism*
  • Tissue Distribution


  • Collagen Type I
  • Collagen Type III