PATHOGENESIS OF BRONCHIAL ASTHMA

Asthma is characterised by airway hyperresponsiveness, airway inflammation and airway remodelling. Airway smooth muscle cells are known to be the main effector cells of airway narrowing. In the present paper, studies will be discussed that have led to a novel view of the role of airway smooth muscle in the pathogenesis of asthma in which airway hyperresponsiveness, remodelling and inflammation are, at least in part, attributable to airway smooth muscle (Zuyderduyn et al., 2008).The current concept of asthma pathogenesis is that a characteristic chronic inflammatory process involving the airway wall causes the development of airflow limitation and increased airway responsiveness, the latter of which predisposes the airways to narrow in response to a variety of stimuli. Characteristic features of the airway inflammation are increased numbers of activated eosinophils, mast cells, macrophages, and T lymphocytes in the airways mucosa and lumen.Airway-tissue remodeling and chronic inflammation of the airways are the most common histopathologic feature of bronchial asthma. Airway remodeling is thought to lead to irreversible airway obstruction, which is one of the factors that make treatment of asthmatic patients difficult.