[The role of airway neurogenic inflammation in gastro-esophageal reflux induced cough].
OBJECTIVE
To investigate the role of airway neurogenic inflammation in the pathogenesis of gastro-esophageal reflux induced cough (GERC).


METHODS
Sputum was induced by hypertonic saline aerosol inhalation in 20 patients with GERC (GERC group), 10 healthy subjects (normal control group) and 8 patients with chronic cough due to other causes but complicated with gastro-esophageal reflux diseases (GERD, GERD group). Airway mucosal biopsy was performed in 6 patients with GERC and 4 patients with GERD using flexible fiberoptic bronchoscopy. The expression of substance P (SP), neurokinin 1 receptor and neurokinin A (NKA) in sputum cells and airway mucosa were detected by immunohistochemistry, and was assessed semi-quantitatively. SP, NKA, and NKB in the supernatant of induced sputum were measured with enzyme linked immunosorbent assay. Calcitonin gene-related peptide (CGRP) was measured with radioimmunoassay.


RESULTS
The concentration of SP in the supernatant of induced sputum was significantly higher in GERC group [(266 +/- 207) ng/L] than those in normal control group [(143 +/- 36) ng/L, P < 0.05] and GERD group [(130 +/- 11) ng/L, P < 0.05], and the sputum supernatant concentration of CGRP in GERC group [(180 +/- 83) ng/L] was significantly higher than those in normal control group [(105 +/- 64) ng/L, P < 0.01] and GERD group [(89 +/- 16) ng/L, P < 0.01]. The expression of SP, NK-1 receptor and NKA in induced sputum cells in GERC group were significantly higher than those in normal control group (P < 0.01, < 0.05, < 0.05) and GERD group (all P < 0.05); Expressions of SP in airway mucosa was significantly higher in GERC group than in GERD group (P < 0.01). After treatment, the concentration of CGRP in the supernatant of sputum in GERC patients was significantly lower than that before treatment (P < 0.05); the expression of SP, NK-1 and NKA in the induced sputum cells were significantly lower than that before treatment (P < 0.01, P < 0.01 or P < 0.05).


CONCLUSIONS
There is airway neurogenic inflammation in GERC patients, which maybe closely related to the development of GERC.
Liu
Chun-li
CL
Guangzhou Institute of Respiratory Disease, First Affiliated Hospital of Guangzhou Medical College, Guangzhou 510120, China.
Lai
Ke-fang
KF
Chen
Ru-chong
RC
Luo
Wei
W
Zeng
Yun-xiang
YX
Yao
Wei-min
WM
Zhong
Nan-shan
NS
D000328:Adult; D016022:Case-Control Studies; D003371:Cough / Q000209:etiology / Q000378:metabolism*; D005260:Female; D005764:Gastroesophageal Reflux / Q000150:complications; D006801:Humans; D008297:Male; D008875:Middle Aged; D009479:Neuropeptides / Q000378:metabolism*; D020545:Respiratory Mucosa / Q000378:metabolism*; D013183:Sputum / Q000378:metabolism; D055815:Young Adult
D009479:Neuropeptides