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Airway smooth muscle in asthma
1Department of Pharmacology, University of Sydney, NSW, Australia. judblack@pharmacol.su.oz.au
Respirology (Carlton, Vic.)
|September 1, 1996
Summary
Airway smooth muscle abnormalities, including increased bulk from hyperplasia and hypertrophy, contribute to asthma-related airway narrowing. Impaired relaxation, possibly due to beta-adrenoceptor dysfunction, also plays a role.
Area of Science:
- Pulmonary Medicine
- Cell Biology
- Pharmacology
Background:
- Asthma is characterized by exaggerated airway narrowing.
- Airway smooth muscle abnormalities are a key contributing factor.
- These abnormalities include increased muscle mass and altered reactivity.
Purpose of the Study:
- To investigate the role of airway smooth muscle abnormalities in asthma.
- To explore the mechanisms behind increased smooth muscle bulk (hyperplasia and hypertrophy).
- To examine potential alterations in smooth muscle pharmacological reactivity, including contraction and relaxation.
Main Methods:
- Review of available evidence on airway smooth muscle changes in asthma.
- Discussion of implicated growth factors, inflammatory mediators, and cytokines.
- Consideration of in vitro pharmacological studies and passive sensitization models.
Main Results:
- Evidence suggests increased smooth muscle bulk results from both hyperplasia and hypertrophy.
- Several growth factors, inflammatory mediators, and cytokines are implicated in smooth muscle growth.
- Limited evidence exists for enhanced contraction; impaired relaxation may involve beta-adrenoceptor dysfunction.
Conclusions:
- Airway smooth muscle abnormalities, encompassing increased bulk and altered reactivity, are significant in asthma.
- Further research is needed to fully understand impaired relaxation mechanisms, particularly beta-adrenoceptor function.
- In vitro passive sensitization models offer a valuable approach for studying airway hyperresponsiveness.