Airway smooth muscle cell culture: application to studies of airway wall remodelling and phenotype plasticity in asthma.
Chronic persistent asthma is characterized by poorly reversible airway obstruction. Histopathological studies of airways removed postmortem from patients with severe asthma reveal marked inflammatory and architectural changes associated with airway wall thickening. Increased airway smooth muscle content, occurring as a result of hyperplastic and/or hypertrophic growth, is believed to be one of the principal contributors to airway wall thickening. Intense interest is building to discover the mechanisms responsible for these long-term structural changes. In vitro cell culture offers a powerful and exacting approach to cellular and molecular studies of the long-term regulation of airway smooth muscle function. This review discusses the methodologies for establishing and maintaining cell cultures of airway smooth muscle. It also describes the characteristics of these cells in culture and addresses the potential importance of phenotype plasticity and its possible relationship to altered smooth muscle function in vivo. Drawing on parallels from vascular studies, this review focuses, in particular, on the synthetic nature of the airway smooth muscle cell, emphasizing its potential to alter the composition of the extracellular matrix environment and orchestrate key events in the process of chronic airway remodelling.