Basic aspects of exhaled nitric oxide

• Nitric oxide (NO) in orally exhaled air mainly originates fromthe respiratory epithelium. NO is produced by inducible NOsynthase (iNOS), which is regulated by signal transducer andactivator of transcription (STAT)-1 under the influence ofhomeostatic interferon-c. In patients with asthma, iNOSexpression is upregulated by interleukin (IL)-4 and IL-13 viathe activation of STAT-6 in the bronchial epithelium. Thus,exhaled NO primarily signals local T-helper cell type 2-driveninflammation in the bronchial mucosa. With these character-istics, exhaled NO will be a suitable marker for predicting theresponse to inhaled corticosteroids, and to monitor the anti-inflammatory effect.The methodology for measuring exhaled NO has beenstandardised based on international consensus. The determi-nants of exhaled NO levels are fairly well characterised, withthe most important being cigarette smoking, nitrate intake, airpollution, allergen sensitisation and exposure, along withheight, sex and age. A future development may be the estima-tion of peripheral airway inflammation by measuring exhaledNO at multiple exhalation flow rates.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine (hsv//eng)

Nyckelord

Asthma

breath test

eosinophil

epithelium

nitric oxide

signal transducer and activator of transcription-6

MEDICINE

MEDICIN

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