The clinical value of exhaled nitric oxide in asthma

Bronchial asthma is an inflammatory disease and measurement of biomarkers in exhaled breath has recently become an attractive approach to non-invasively monitor airway inflammation. In bronchial asthma, increased fractional exhaled nitric oxide (FeNO) concentration in exhaled breath has been shown to reflect the extent of eosinophilic inflammation. Moreover, the increase of FeNO levels are suppressed by inhaled corticosteroids (ICS). Therefore, monitoring of FeNO is a useful marker of inflammation in asthma and it has proven to be very effective in the differential diagnosis of allergic asthma, predicting the response to ICS therapy. Several FeNO analyzers are commercially available. Because of great advances in technology a wide range of hand-held FeNO analyzers and smaller less costly devices are now becoming available, making FeNO measurement a routine test in the primary care of asthmatic patients. In the first study we tested a new portable device to investigate correlation and agreement with the standard stationary device. Nowadays, overweight and obesity are common conditions worldwide. In particular, the incidence of overweight and obesity in Italian people is estimated almost of 32% and 10%, respectively. Obesity has been considered as a proinflammatory state and therefore several studies have been investigated the relationship between elevated body mass index (BMI) and asthma. In the second study we aimed to investigate in a large cohort of Italian asthmatic patients whether or not overweight patients were different from normal weight subjects both in terms of clinical and functional features and in terms of airway inflammation, as assessed by FeNO measurement. Although the clinical application of FeNO is still needed to be fully clarified, the use of this marker in clinical practice is providing a useful adjunct to conventional tools for the assessment and management of the respiratory disease. There is a general agreement that the development of new techniques detecting the distinct patterns of biomarkers in exhaled breath heralds the beginning of the era of †œBreathomics†�. In this regard, future developments may include FeNO †œbreathograms†� to aid early detection, diagnosis and follow-up of airways diseases.