Bronchial Reactivity to Histamine Is Correlated With Airway Remodeling in Adults With Moderate to Severe Asthma

Abstract

Background. Chronic eosinophilic inflammation may promote airway remodeling, including thickening of the reticular basement membrane (RBM), hypertrophy and hyperplasia of the airway smooth muscles (ASM), and an increase in the production of tenascin. The authors examined the correlation between airway remodeling and bronchial reactivity to histamine (Hist) and acetylcholine (ACh) in patients with moderate to severe asthma. Methods. In 30 adult patients with asthma, the authors assessed bronchial hyperresponsiveness (BHR) to various concentrations of ACh and Hist by measuring decreases in forced expiratory volume in one second (FEV₁) of >20% from the preprovocation state, and % recoveries of FEV₁ after inhalation of β-stimulant. After corticosteroid therapy, the authors evaluated the thickening of RBM and ASM and the production of tenascin in bronchial specimens. Results. The % decrease in FEV₁ was correlated with the % recovery in FEV₁ after provocation by ACh or Hist. Hypertrophy of ASM was correlated with the % decrease in FEV1 after provocation by Hist, but not by ACh. Thickening of ASM, up-regulation of tenascin in RBM, and duration of asthma were inversely correlated with the % recovery of FEV₁ after provocation by Hist, but not by ACh. Conclusions. In adult patients with moderate to severe asthma, a strong bronchial contraction provoked by Hist and a subsequent small recovery indicate airway remodeling.

• acetylcholine
• airway remodeling
• bronchial asthma
• bronchial hyperresponsiveness
• eosinophilic inflammation
• histamine