Mediators in exhaled breath condensate after hypertonic saline challenge

J Asthma. 2009 Dec;46(10):1045-51. doi: 10.3109/02770900903301252.

Abstract

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.

Conclusion: 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.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Asthma / metabolism*
  • Asthma / physiopathology
  • Breath Tests
  • Bronchi / drug effects
  • Bronchi / metabolism*
  • Bronchial Hyperreactivity / chemically induced
  • Bronchial Hyperreactivity / diagnosis
  • Bronchial Hyperreactivity / metabolism*
  • Bronchial Hyperreactivity / physiopathology
  • Bronchial Provocation Tests*
  • Child
  • Eosinophil Cationic Protein / metabolism
  • Female
  • Forced Expiratory Volume / physiology
  • Histamine / metabolism
  • Humans
  • Hydrogen-Ion Concentration
  • Inflammation Mediators / metabolism*
  • Male
  • Middle Aged
  • Mucins / metabolism
  • Nitric Oxide / metabolism
  • Nitrites / metabolism
  • Saline Solution, Hypertonic / pharmacology*
  • Tryptases / metabolism
  • Water / metabolism
  • Young Adult

Substances

  • Inflammation Mediators
  • Mucins
  • Nitrites
  • Saline Solution, Hypertonic
  • Water
  • Nitric Oxide
  • Histamine
  • Eosinophil Cationic Protein
  • Tryptases