Role of COX-2 in cough reflex sensitivity to inhaled capsaicin in patients with sinobronchial syndrome.
BACKGROUND
Sinobronchial syndrome is a cause of chronic productive cough. Inflammatory mediators are involved in the pathophysiology of chronic productive cough. Accumulating evidences indicate that cyclooxygenase (COX)-2, one of the inducible isoforms of COX, is a key element in the pathophysiological process of a number of inflammatory disorders. However, little is known about the role of COX-2 in chronic productive cough in patients with sinobronchial syndrome known as neutrophilic bronchial inflammation.


METHODS
The effect of etodolac, a potent COX-2 inhibitor, on cough response to inhaled capsaicin was examined in 15 patients with sinobronchial syndrome in a randomized, placebo-controlled cross-over study. Capsaicin cough threshold, defined as the lowest concentration of capsaicin eliciting five or more coughs, was measured as an index of airway cough reflex sensitivity.


RESULTS
The cough threshold was significantly (p < 0.03) increased after two-week treatment with etodolac (200 mg twice a day orally) compared with placebo [37.5 (GSEM 1.3) vs. 27.2 (GSEM 1.3) muM].


CONCLUSIONS
These findings indicate that COX-2 may be a possible modulator augmenting airway cough reflex sensitivity in patients with sinobronchial syndrome.
Ishiura
Yoshihisa
Y
The Department of Internal Medicine, Toyama City Hospital, Toyama, Japan. ishiura-@p2322.nsk.ne.jp.
Fujimura
Masaki
M
Yamamoto
Hiroki
H
Ohkura
Noriyuki
N
Myou
Shigeharu
S