title: Structural changes of the airway wall impair respiratory function, even in mild asthma.
abstract: OBJECTIVE
  To clarify whether structural changes of the airway wall impair respiratory function in patients with mild asthma, and to determine whether mild asthma should be treated with inhaled steroids.
  
  
  METHODS
  Showa University Hospital in Tokyo.
  
  
  METHODS
  Thirteen healthy nonatopic volunteers (control subjects), 26 patients with mild asthma treated with a bronchodilator alone without oral or inhaled corticosteroids or antiallergic agents, and 10 patients with mild-to-moderate asthma treated with inhaled corticosteroids.
  
  
  METHODS
  We measured the thickness of the epithelial reticular basement membrane (Rbm) of the airway wall in bronchial biopsy specimens from patients with asthma and from healthy control subjects. We also performed spirometry and histamine challenge tests to evaluate airflow obstruction and airway hyperresponsiveness.
  
  
  RESULTS
  The thickness of the Rbm in patients with mild asthma was significantly greater than that in healthy control subjects and was negatively correlated with the FEV(1) as a percentage of FVC and the provocative concentration of histamine that caused a 20% decrease in FEV(1) from the post-saline solution baseline value. Moreover, the Rbm was thicker in patients with mild asthma not treated with inhaled steroids than in patients with mild-to-moderate asthma treated with inhaled steroids.
  
  
  CONCLUSIONS
  The thickness of the Rbm is increased even in mild asthma and is correlated with airway obstruction and hyperresponsiveness. Our results suggests that anti-inflammatory treatment with inhaled steroids should be started in the early stage of bronchial asthma to prevent structural changes from occurring in the airway wall.
authors.affiliation: First Department of Internal Medicine, Showa University School of Medicine, Tokyo, Japan.
authors.forename: Kumiko
authors.initials: K
authors.lastname: Shiba
authors.forename: Keita
authors.initials: K
authors.lastname: Kasahara
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Nakajima
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Adachi
mesh_terms: D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D000328:Adult; D001249:Asthma / Q000188:drug therapy / Q000473:pathology* / Q000503:physiopathology*; D001485:Basement Membrane / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D012129:Respiratory Function Tests; D012720:Severity of Illness Index
chemical_list: D000305:Adrenal Cortex Hormones