الفهرس 
Bronchial asthmaOnly 14 pages are availabe for public view
 |  | from | 222 |  |  |
| | | from | 222 | | |
Abstract
Asthma is a disease that has been defined by its characteristics of airway hyperresponsiveness, airflow obstruction, and inflammation
Chronic (typically eosinophilic) airway inflammation and remodeling are pathological hallmarks of asthma, but heterogeneity of clinical presentation, accompanying atopy, clinical severity, airway inflammation, and genetic predispositions indicate that asthma is a syndrome rather than a single disease.
Airway smooth muscle cell often regarded as a passive cell (responsible for bronchomotor tone, responding to neurogenic signals and inflammatory mediators). Now acknowledged as an active participant in the inflammatory and allergic events that accompany persistent asthma. Together, airway smooth muscle contraction and obstruction can result in a 75-fold increase in airflow obstruction. Recent data suggested that in asthma, the contractility of airway smooth muscle is unchanged and that bronchospasm results from increased shortening of a normal muscle by a variety of agonists released from infiltrating cells.
The airway smooth muscle cell has many roles in the airway that releases a number of cytokines, expresses adhesion molecules that engage inflammatory cells, produces extracellular matrix proteins that influence its function, proliferates in response to growth factors and cytokines and migrates underneath the epithelium.
Since airway smooth muscle cells are intrinsically different in asthmatic patients they are likely to be intimately involved in the remodeling process and the progression of the asthmatic phenotype. Their role in airway disease is only beginning to be understood, and in the future the interaction of allergens and lower respiratory tract infections with the smooth muscle cell may yield valuable insights into the pathogenesis of asthma and other respiratory diseases.
The airway smooth muscle cells are the therapeutic targets for drugs used to treat asthma and other airway disorders. Traditionally, drugs used to treat asthma were categorized according to their predominant effect-relaxation of airway smooth muscle (bronchodilators) or suppression of airway inflammation (anti-inflammatory drugs). Newer medications (e.g the leukotriene modifiers) and drug combinations (e.g inhaled corticosteroids combined with long β adrenergic agonists) have dual effects, resisting such traditional dichotomization.
In addition to targeting a specific component of the ASM cells, another strategy is being explored. Bronchial thermoplasty (BT) is used to obliterate ASM cells from the airway wall. This technique delivers radiofrequency energy to the airway wall, which heats up the airway tissue and reduces ASM mass.