Asthma: Application of Cell and Molecular Biology Techniques to Unravel Causes and Pathophysiological Mechanisms

Abstract

The condition termed "asthma" has been difficult to define satisfactorily. Much of this problem arises from poor understanding of its causes, natural history, and pathophysiology, and also from a lack of a specific marker(s) of the disease. To the clinician, the diagnosis of asthma is not difficult in most cases, particularly if patients present early with symptoms of intermittent wheeze and chest tightness, and if their symptoms respond to particular treatments, such as β-adrenergic agonists. Early definitions of asthma included the presence of airway obstruction that could spontaneously reverse with treatment, and also the increased narrowing of the airways to non-specific bronchoconstrictor stimuli, i.e., bronchial hyperresponsiveness (BHR). The essential elements of this definition were useful in separating asthma from other conditions, such as chronic bronchitis, chronic obstructive pulmonary disease, and emphysema, which could sometimes be diagnostically confused with asthma. More recently, the definition of asthma has been enhanced by the recognition that the airway submucosa of patients with asthma are chronically inflamed with a typical inflammatory infiltrate, and that inflammatory processes are important causes of the chief characteristics of asthma: airway obstruction and BHR. In addition, the loss of reversibility of airway obstruction as a long-term effect of the chronic inflammatory process is recognized:

n-3 Fatty acids and asthma

“…Episodic symptoms after allergen exposures, seasonal variability and a positive family history and atopy are useful diagnostic guidelines (39) . The presentation of asthma can vary from person to person and asthma may be intermittent with mild to severe episodes requiring treatment (40,41) . Asthmatics may experience intermittent symptoms for a period (42,43) .…”

Loss of regulator of G protein signaling 5 promotes airway hyperresponsiveness in the absence of allergic inflammation

“…Asthma is characterized by hyperresponsiveness of the airways (AHR) and infiltration of inflammatory leukocytes in the lung, typically associated with allergen exposure 1 . Airway smooth muscle (ASM) contraction is triggered primarily by spasmogens activating Gα q -linked G protein-coupled receptors (GPCRs), including the M3 muscarinic, cysteinyl leukotriene, thrombin, histamine H1, and bradykinin receptors 2 , and ligands for many of these GPCRs are increased in lungs of allergic asthmatics.…”

Role of interleukin‐13 in eosinophil accumulation and airway remodelling in a mouse model of chronic asthma

“…Asthma is a disorder characterized by episodic airflow obstruction and hyper‐reactivity of the airways to a variety of stimuli [1]. Although most asthma is associated with atopy, the pathological basis of the clinical features of asthma remains poorly defined.…”