Variability in the precursor proteins of collagen I and III in different stages of COPD.
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.
Institute of Clinical Medicine, Department of Internal Medicine, Respiratory Unit, Centre of Excellence in Research, P, O, Box 5000, 90014 University of Oulu, Oulu, Finland. terttu.harju@oulu.fi
Terttu
T
Harju
Vuokko L
VL
Kinnula
Paavo
P
Pääkkö
Kaisa
K
Salmenkivi
Juha
J
Risteli
Riitta
R
Kaarteenaho
D000368:Aged; D024042:Collagen Type I / Q000378:metabolism*; D024061:Collagen Type III / Q000378:metabolism*; D018450:Disease Progression; D005260:Female; D006801:Humans; D008168:Lung / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000378:metabolism*; D012680:Sensitivity and Specificity; D012907:Smoking / Q000378:metabolism*; D014018:Tissue Distribution
D024042:Collagen Type I; D024061:Collagen Type III