Sleep apnea is associated with bronchial inflammation and continuous positive airway pressure-induced airway hyperresponsiveness.
BACKGROUND
Obstructive sleep apnea syndrome (OSA) is associated with systemic and upper airway inflammation. Pharyngeal inflammation has a potential role in upper airway collapse, whereas systemic inflammation relates to cardiovascular morbidity. However, the presence of an inflammatory involvement of lower airway has been poorly investigated.


OBJECTIVE
The aim of the study was to demonstrate an inflammatory process at the bronchial level in patients with OSA and to analyze effects of continuous positive airway pressure (CPAP) application and humidification on bronchial mucosa.


METHODS
The study was conducted by using sequential induced sputum for cell analysis and IL-8 production, nitric oxide exhalation measurement, and methacholine challenge before and after CPAP.


RESULTS
Bronchial neutrophilia and a high IL-8 concentration were observed in untreated OSA compared with controls (75% +/- 20% vs 43% +/- 12%, P < .05; and 25.02 +/- 9.43 ng/mL vs 8.6 +/- 3.7 ng/mL, P < .001, respectively). IL-8 in sputum supernatant was correlated to apnea hypopnea index (P < .01; r = 0.81). After 1 month of CPAP, this inflammatory pattern remained unchanged, and an increase in airway hyperresponsiveness (AHR) was observed (P < .001).


CONCLUSIONS
Obstructive sleep apnea syndrome is associated with bronchial inflammation. Our data demonstrate CPAP effect on the development of AHR, possibly facilitated by the pre-existing inflammation. Both issues should be evaluated during long-term CPAP use.


CONCLUSIONS
Results showing a spontaneous bronchial inflammation in OSA and the development of a CPAP-related AHR require a long-term follow-up to evaluate consequences on chronic bronchial obstruction.
Devouassoux
Gilles
G
Sleep Laboratory, Exploration Fonctionnelle Cardio-Respiratoire, University Hospital Grenoble, Grenoble Cedex, France.
Lévy
Patrick
P
Rossini
Eliane
E
Pin
Isabelle
I
Fior-Gozlan
Michèle
M
Henry
Mireille
M
Seigneurin
Daniel
D
Pépin
Jean-Louis
JL
D000328:Adult; D001980:Bronchi / Q000187:drug effects; D016535:Bronchial Hyperreactivity / Q000175:diagnosis / Q000209:etiology*; D001991:Bronchitis / Q000175:diagnosis / Q000209:etiology* / Q000276:immunology; D016085:Bronchoconstrictor Agents / Q000494:pharmacology; D045422:Continuous Positive Airway Pressure / Q000009:adverse effects*; D045853:Exhalation; D005260:Female; D006801:Humans; D016209:Interleukin-8 / Q000032:analysis; D008297:Male; D016210:Methacholine Chloride / Q000494:pharmacology; D008875:Middle Aged; D009504:Neutrophils / Q000276:immunology; D009569:Nitric Oxide / Q000378:metabolism; D020545:Respiratory Mucosa / Q000187:drug effects; D020181:Sleep Apnea, Obstructive / Q000150:complications* / Q000628:therapy; D013183:Sputum / Q000737:chemistry / Q000166:cytology / Q000276:immunology
D016085:Bronchoconstrictor Agents; D016209:Interleukin-8; D016210:Methacholine Chloride; D009569:Nitric Oxide