PT  - JOURNAL ARTICLE
AU  - Robyn Jones
AU  - John Elliot
AU  - Peter Noble
AU  - Peter MvFawn
AU  - James Hogg
AU  - Alan James
TI  - The relation of cigarette smoking to increased extracellular matrix in the layer of airway smooth muscle
AID  - 10.1183/13993003.congress-2015.PA5050
DP  - 2015 Sep 01
TA  - European Respiratory Journal
PG  - PA5050
VI  - 46
IP  - suppl 59
4099  - http://erj.ersjournals.com/content/46/suppl_59/PA5050.short
4100  - http://erj.ersjournals.com/content/46/suppl_59/PA5050.full
SO  - Eur Respir J2015 Sep 01; 46
AB  - Reduced FEV1 in smokers may be due to the combined effects of pre-existing airway remodeling and/or progressive loss of lung function (due to emphysema or airway remodeling). We have previously observed an inverse relationship between FEV1 and the volume fraction of extracellular matrix (VVECM) in the layer of airway smooth muscle (ASM). Given the increased decline in FEV1 in smokers, we hypothesized that this relationship reflects progressive remodeling of the ASM in smokers.Aim: To examine the relationship between smoke exposure and VVECM within the ASM layer in smokers and non-smokers undergoing lung resection.Methods: Prior to surgery, FEV1 was measured and smoking history was recorded. Post-operative tissue was obtained from current smokers (n=10), ex-smokers (n=20) and never smokers (n=9). Transverse sections (0.5μm thick) of large and small airway were stained with the Masson's trichrome technique. VVECM within the ASM layer was estimated and related to age, duration of smoking and number cigarettes smoked per week.Results: Mean pack-years of smoking was 49±39 (range 4-160). VVECM was increased in current (p=0.001) and ex-smokers (p=0.016) compared with non-smokers in the large airways. VVECM was not related to pack years (r2=0.036, p=0.38), duration of smoking (r2=0.035, p=0.41), number of cigarettes smoked (r2=0.008, p=0.69) or age (r2=0.007, p=0.68) in large or small airways.Conclusion: Although increase VVECM in the ASM layer is related to FEV1 and current smoking, we could not detect a dose effect of smoking. This suggests a non-progressive effect of smoking and the presence of pre-existing remodeling of the ASM layer or a threshold effect of cigarette smoking.