Airway Wall Remodeling: The Influence of Corticosteroids
Purpose of the Review: We have attempted to bring together recent findings, mainly from airway endobronchial biopsies, on the structural changes that constitute 'remodelling' in airway disease, with a particular focus on asthma. We have tried to put this into the context of classic studies on the asthma pathological phenotype. Having described these basic changes, we have then given an update on recent studies investigating the effects of corticosteroid medication on the different manifestations of remodelled airways.
Recent Findings: The effects of corticosteroid on airway remodelling seem to vary a great deal; some aspects are steroid responsive while others are not, or less so. It is likely that different manifestations of remodelling require different doses and timescales for treatment to be effective.
Summary: Further longitudinal interventional studies are required, with multiple airway sampling times, to fully elucidate the full potential for corticosteroids to benefit remodelling of the airways in chronic inflammatory diseases. There needs to be more attention to pathophysiological and clinical correlations in such studies. It is likely that even when used optimally corticosteroids will have limited efficacy overall in this aspect of asthma pathogenesis. The search is on for newer and better treatments.

Structural wall changes, as part of the pathobiology of airways diseases, have been referred to as airway remodelling (Figs 1 and 2). This has been most studied in asthma, but also occurs in chronic obstructive pulmonary disease, cystic fibrosis and obliterative bronchiolitis following lung transplantation. Most of our attention will be addressed to asthma, though it is likely that many of the lessons learned there will be applicable elsewhere. Research efforts on airway remodelling have been especially driven by the hypothesis that airway structural changes may underlie the development of fixed airflow limitation, but studies including pathophysiological correlation have been limited. There is particular need for prospective longitudinal study of the effects of medication on such relationships.


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Consolidated concepts: the big picture


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Where do fibroblasts come from?