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Airway remodeling in asthma
N. Anastasiou, S. Loukides
SUMMARY: Asthma represents a chronic inflammatory process of the airways
followed by healing whose end result may be an altered structure referred to
as remodeling of the airways. Remodeling in asthma is characterized by the following
structural changes: Hypertrophy/hyperplasia of airway smooth muscle, increase
in mucus glands, thickening of the reticular basement membrane, vascular dilation/angiogenesis
and ECM deposition. Mechanisms of airway remodeling involve growth factor expression,
protease/antiprotease balance, chronic antigen challenge, Th2 cytokines, myofibroblast
hyperplasia, leukotrienes, IL-6 group cytokines, tryptases and possible genetic
susceptibility. Despite the evidence that supports a close relationship between
remodeling and clinical severity, the presence of airway remodeling is considered
as an independent factor in the whole pathophysiological process of the disease.
Low postbronchodilator FEV1/VC ratio in early
life confirms the start of airway remodeling in childhood. The efficacy of anti-inflammatory
treatment on the natural course of remodeling is still debated. Inhaled corticosteroids
seemed to be the ideal treatment although they suppress part of the whole remodeling
process without reversing it. Recent in vivo evidence supports the beneficial
effect of long acting â2 agonists. We still need further research in order to
better understand the relationship between remodeling, the natural history of
the disease and the early relevant markers that might predict its appearance
and its progress. Pneumon 2003, 16(2):142-152.
Key words: Asthma, airways, remodeling.
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