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Lookup NU author(s): Professor Christopher WardORCiD
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
Background: Small airway fibrosis is the main contributor in airflow obstruction in chronic obstructive pulmonary disease. Epithelial mesenchymal transition (EMT) has been implicated in this process, and in large airways, is associated with angiogenesis, ie, Type-3, which is classically promalignant.Objective: In this study we have investigated whether EMT biomarkers are expressed in small airways compared to large airways in subjects with chronic airflow limitation (CAL) and what type of EMT is present on the basis of vascularity.Methods: We evaluated epithelial activation, reticular basement membrane fragmentation (core structural EMT marker) and EMT-related mesenchymal biomarkers in small and large airways from resected lung tissue from 18 lung cancer patients with CAL and 9 normal controls. Tissues were immunostained for epidermal growth factor receptor (EGFR; epithelial activation marker), vimentin (mesenchymal marker), and S100A4 (fibroblast epitope). Type-IV collagen was stained to demonstrate vessels.Results: There was increased expression of EMT-related markers in CAL small airways compared to controls: EGFR (P < 0.001), vimentin (P < 0.001), S100A4 (P < 0.001), and fragmentation (P < 0.001), but this was less than that in large airways. Notably, there was no hypervascularity in small airway reticular basement membrane as in large airways. Epithelial activation and S100A4 expression were related to airflow obstruction.Conclusion: EMT is active in small airways, but less so than in large airways in CAL, and may be relevant to the key pathologies of chronic obstructive pulmonary disease, small airway fibrosis, and airway cancers.
Author(s): Mahmood MQ, Sohal SS, Shukla SD, Ward C, Hardikar A, Noor WD, Muller HK, Knight DA, Walters EH
Publication type: Article
Publication status: Published
Journal: International Journal of Chronic Obstructive Pulmonary Disease
Online publication date: 04/08/2015
Acceptance date: 20/04/2015
Date deposited: 31/03/2016
ISSN (print): 1176-9106
ISSN (electronic): 1178-2005
Publisher: Dove Medical Press Ltd
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