Elevation of sputum matrix metalloproteinase-9 persists up to 6 months after smoking cessation: a research study.
BACKGROUND
Smoking cessation is the best possible way to prevent the progression of smoking related airway diseases. However, the effect and time scale of smoking cessation on airway inflammation/remodelling are largely unknown. This prospective study evaluated the effects of smoking cessation on induced sputum (IS) neutrophils, matrix metalloproteinases (MMP-7, -8, -9) and tissue inhibitor of metalloproteinase-1 (TIMP-1).


METHODS
A total of 61 subjects participated in the study; 17 stopped smoking for 3 months and 9 for 6 months. The proportion of IS neutrophils and the levels of MMPs and TIMP-1 by ELISA were determined at baseline and at 3 and 6 months after cessation.


RESULTS
In the smokers, baseline IS neutrophils, MMPs and TIMP-1 were significantly higher compared to non-smokers. Levels of MMP-7, -8 and TIMP-1 decreased nearly to those of non-smokers but the levels of MMP-9 increased significantly from the baseline of the same subjects at 3 months after cessation (p = 0.009) with no significant decline at 6 months after cessation.


CONCLUSIONS
Sputum MMP-9 remained elevated after 6 months of smoking cessation, which may contribute to ongoing lung damage typical of COPD.
Louhelainen
Noora
N
Department of Medicine, Division of Pulmonary Medicine, University of Helsinki, Helsinki, Finland.
Stark
Harri
H
Mazur
Witold
W
Rytilä
Paula
P
Djukanovic
Ratko
R
Kinnula
Vuokko L
VL
D000328:Adult; D000368:Aged; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008297:Male; D020783:Matrix Metalloproteinase 7 / Q000378:metabolism; D020784:Matrix Metalloproteinase 8 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D008875:Middle Aged; D009504:Neutrophils / Q000378:metabolism; D011446:Prospective Studies; D012907:Smoking / Q000378:metabolism*; D016540:Smoking Cessation; D013183:Sputum / Q000201:enzymology*; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism
D019715:Tissue Inhibitor of Metalloproteinase-1; C060932:MMP7 protein, human; D020783:Matrix Metalloproteinase 7; D020784:Matrix Metalloproteinase 8; D020780:Matrix Metalloproteinase 9