Table of Contents
ISRN Inflammation
Volume 2012, Article ID 731472, 13 pages
http://dx.doi.org/10.5402/2012/731472
Research Article

Cytokines and Growth Factors Promote Airway Smooth Muscle Cell Proliferation

1Department of Physiology, Faculty of Medicine, University of Thessaly, Biopolis, 41110 Larissa, Greece
2Department of Respiratory Medicine, Faculty of Medicine, University of Thessaly, 41110 Larissa, Greece

Received 17 April 2012; Accepted 29 May 2012

Academic Editors: A. Bossios, M. Hukkanen, and D. Szukiewicz

Copyright © 2012 R. Stamatiou et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Chronic airway diseases, such as asthma or chronic obstructive pulmonary disease, are characterized by the presence in the airways of inflammation factors, growth factors and cytokines, which promote airway wall remodelling. The aim of this study was to investigate the effect of cytokines and growth factors on airway smooth muscle cell (ASMC) proliferation, phenotype and responsiveness. Incubation of serum starved human bronchial ASMCs with TNF-α, TGF, bFGF, and PDGF, but not IL-1β, increased methyl-[3H]thymidine incorporation and cell number, mediated by the PI3K and MAPK signalling pathways. Regarding rabbit tracheal ASMC proliferation, TNF-α, IL-1β, TGF, and PDGF increased methyl-[3H]thymidine incorporation in a PI3K- and MAPK-dependent manner. bFGF increased both methyl-[3H]thymidine incorporation and cell number. Moreover, incubation with TGF, bFGF and PDGF appears to drive human ASMCs towards a synthetic phenotype, as shown by the reduction of the percentage of cells expressing SM-α actin. In addition, the responsiveness of epithelium-denuded rabbit tracheal strips to carbachol was not significantly altered after 3-day treatment with bFGF. In conclusion, all the tested cytokines and growth factors increased ASMC proliferation to a different degree, depending on the specific cell type, with bronchial ASMCs being more prone to proliferation than tracheal ASMCs.