Treating Asthma as an Inflammatory Disease: Airway Remodeling

A study of the natural history of respiratory allergy enrolled 142 patients with either allergic rhinitis or allergic asthma and observed them for 10 years. In the 99 subjects who completed the study, 50% of patients with asthma also acquired rhinitis and 31.8% of patients with rhinitis also acquired asthma. Positive family history for atopy was found to be associated with evolution of either rhinitis or asthma to rhinitis plus asthma (Table 1; p = 0.01). Treatment of rhinitis has also been shown to reduce emergency visits for asthma.
Regarding treatment options, oral and nasal antihistamines and nasal corticosteroids are commonly used to treat rhinitis, whereas the cornerstone of treatment and “gold standard” for the long-term control of asthma is ICS. Leukotriene receptor antagonists (LTRAs), which are generally used to treat asthma, may be used in patients with asthma who also have concomitant rhinitis. B-Receptor agonists are effective in asthma but are not used in rhinitis. ICS are considered the most potent and consistently effective long-term control medication for asthma. read more

Remodeling is a critical aspect of wound repair in all organs. It represents a dynamic process that occurs in reaction to an inflammatory insult. In asthma, remodeling results in changes in the composition, content, and organization of the cellular and molecular constituents of the airway wall.
Acute inflammation usually resolves with normal repair processes, but with chronic inflammation the repair process is disturbed, leading to remodeling. The process of remodeling involves thickening of the airway walls as a result of subepithelial fibrosis, myocyte hyperplasia and hypertrophy, myofibroblast hyperplasia, epithelial hypertrophy, and mucus gland and goblet cell hyperplasia. The airway wall is edematous, and the mucosa and submucosa are infiltrated with eosinophils and T-cells. The basement membrane is thickened, and there is desquamation of epithelium. In summary, the change that occurs in both the structure and geometry of airways in pathologic conditions has been termed remodeling. The sites of airway remodeling include the epithelium and basal membrane, airway smooth muscle, mucous glands, extracellular matrix, and small and large vessels.

Table 1—Natural History of Respiratory Allergy (Allergic Rhinitis or Allergic Asthma) in 99 of 142 Patients Completing 10 Years of Follow-up

Variables Skin Tests Family History
One or Two Positive Results More Than Two Positive Results p Value Negative for Atopy Positive for Atopy p Value
Rhinitis to rhinitis plus asthma 5/14 (36) 9/14 (64) NS 2/14 (14) 12/14 (85) 0.01
Asthma to asthma plus rhinitis 3/6 (50) 3/6 (50) NS 1/6 (17) 5/6 (83) 0.01
This entry was posted in Asthma and tagged allergic rhinitis, asthma, corticosteroids, inflammation, remodeling.