Effect of short-term treatment with inhaled corticosteroid on airway wall thickening in asthma.
OBJECTIVE
Computed tomography studies demonstrate thickening of the asthmatic airway wall and its relation to disease severity. We evaluated the effect of inhaled corticosteroid on this phenomenon.


METHODS
Cross-sectional images of the right upper lobe apical segmental bronchus were obtained by helical computed tomography in 45 corticosteroid-naïve patients with persistent asthma and 28 healthy controls. Airway wall thickness was measured as airway wall area normalized to body surface area. Computed tomography, pulmonary function, and serum levels of eosinophil cationic protein were examined before and after treatment with beclomethasone (800 microg/d for 12 weeks).


RESULTS
Before treatment, airway wall thickness was greater in asthma patients than in controls (P <0.0001). After treatment, it decreased by 11% (P <0.001) but remained high (P <0.0001 vs. control); the serum level of eosinophil cationic protein decreased, and airflow obstruction was reduced, but not to the level in controls. The decrease in wall thickness was associated with a decrease in the serum level of eosinophil cationic protein (r = 0.39, P = 0.009) and an increase in the forced expiratory volume in 1 second (r = 0.45, P = 0.003) and was inversely related to disease duration at entry (r = -0.38, P = 0.009). Post-treatment wall thickness was related to disease duration (r = 0.45, P = 0.003) and remaining airflow obstruction.


CONCLUSIONS
Wall thickening of asthmatic central airways responds partially to inhaled corticosteroid therapy and may reflect an overall reduction in airway inflammation. "Unresponsive components," possibly involving structural changes, may increase in the absence of inhaled corticosteroid treatment, potentially leading to chronic airflow obstruction.
Niimi
Akio
A
Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan. niimi@kuhp.kyoto-u.ac.jp
Matsumoto
Hisako
H
Amitani
Ryoichi
R
Nakano
Yasutaka
Y
Sakai
Hiroaki
H
Takemura
Masaya
M
Ueda
Tetsuya
T
Chin
Kazuo
K
Itoh
Harumi
H
Ingenito
Edward P
EP
Mishima
Michiaki
M
D000280:Administration, Inhalation; D000328:Adult; D000368:Aged; D001249:Asthma / Q000097:blood / Q000000981:diagnostic imaging / Q000188:drug therapy*; D001507:Beclomethasone / Q000008:administration & dosage*; D001798:Blood Proteins; D004334:Drug Administration Schedule; D047091:Eosinophil Granule Proteins; D005260:Female; D005500:Follow-Up Studies; D005938:Glucocorticoids / Q000008:administration & dosage*; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000187:drug effects*; D008297:Male; D008875:Middle Aged; D012129:Respiratory Function Tests; D020545:Respiratory Mucosa / Q000000981:diagnostic imaging / Q000187:drug effects; D012260:Ribonucleases / Q000097:blood; D013997:Time Factors; D014057:Tomography, X-Ray Computed
D001798:Blood Proteins; D047091:Eosinophil Granule Proteins; D005938:Glucocorticoids; D012260:Ribonucleases; D001507:Beclomethasone