Mediators in exhaled breath condensate after hypertonic saline challenge.
BACKGROUND
Airway narrowing after hypertonic saline challenge (HSC) is postulated to be mediated by bronchoconstrictors and inflammatory mediators.


OBJECTIVE
To study the mechanism of this challenge by using exhaled breath condensate (EBC).


METHODS
Fifty-six subjects (9 to 72 years of age) performed an HSC, with EBC collection and exhaled nitric oxide (FENO) measurements before and after the challenge. Bronchial hyper-reactivity (BHR) was defined if forced expiratory volume in 1 second (FEV1) decreased by 10% compared with baseline (PD10). EBC volume was recorded and was analyzed for mucin, histamine, nitrite/nitrate, and pH.


RESULTS
Those with BHR had a significant rise in EBC volume/5-minute collection period after challenge (286.3 +/- 25.6 microl vs 402.2 +/- 31.3 microl, p = 0.0002), while BHR(-) subjects did not show this change (387.6 +/- 29.7 microl vs 364.1 +/- 30.1 microl, p = 0.55). FENO showed a significant decrease in both BHR(+) and BHR(-) groups after challenge (p = < 0.0001). In BHR(+) subjects histamine increased significantly (1.3 +/- 0.1 microM vs 1.5 +/- 0.1 microM, p = 0.006) compared with baseline, while EBC pH and mucin increased significantly after HSC in both groups. EBC nitrite did not change in either group.


CONCLUSIONS
EBC analysis suggests that HSC causes an increase in pH and mucin in both groups, but EBC volume and histamine only increased in the BHR(+) group. This suggests that mast cells are activated and fluid flux is associated with the positive response, while mucin release is independent of BHR in HSC.
Ratnawati
Centre for Infection and Inflammation Research, School of Medical Sciences, University of New South Wales, New South Wales, Australia.
Morton
John
J
Henry
Richard L
RL
Thomas
Paul S
PS
D000293:Adolescent; D000328:Adult; D000368:Aged; D001249:Asthma / Q000378:metabolism* / Q000503:physiopathology; D001944:Breath Tests; D001980:Bronchi / Q000187:drug effects / Q000378:metabolism*; D016535:Bronchial Hyperreactivity / Q000139:chemically induced / Q000175:diagnosis / Q000378:metabolism* / Q000503:physiopathology; D001985:Bronchial Provocation Tests; D002648:Child; D047150:Eosinophil Cationic Protein / Q000378:metabolism; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006632:Histamine / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D018836:Inflammation Mediators / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009077:Mucins / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D012462:Saline Solution, Hypertonic / Q000494:pharmacology*; D053802:Tryptases / Q000378:metabolism; D014867:Water / Q000378:metabolism; D055815:Young Adult
D018836:Inflammation Mediators; D009077:Mucins; D009573:Nitrites; D012462:Saline Solution, Hypertonic; D014867:Water; D009569:Nitric Oxide; D006632:Histamine; D047150:Eosinophil Cationic Protein; D053802:Tryptases