Exhaled Nitric Oxide as a Biomarker in COPD and Related Comorbidities

Abstract

Chronic Obstructive Pulmonary Disease (COPD) is defined as a disease characterized by persistent, progressive airflow limitation. Recent studies have underlined that COPD is correlated to many systemic manifestations, probably due to an underlying pattern of systemic inflammation. In COPD fractional exhaled Nitric Oxide (FeNO) levels are related to smoking habits and disease severity, showing a positive relationship with respiratory functional parameters. Moreover FeNO is increased in patients with COPD exacerbation, compared with stable ones. In alpha-1 antitrypsin deficiency, a possible cause of COPD, FeNO levels may be monitored to early detect a disease progression. FeNO measurements may be useful in clinical setting to identify the level of airway inflammation, per se and in relation to comorbidities, such as pulmonary arterial hypertension and cardiovascular diseases, either in basal conditions or during treatment. Finally, some systemic inflammatory diseases, such as psoriasis, have been associated with higher FeNO levels and potentially with an increased risk of developing COPD. In these systemic inflammatory diseases, FeNO monitoring may be a useful biomarker for early diagnosis of COPD development.

Increased airway inflammation in patients with psoriasis

“…Our study reveals that before treatment the FeNO levels of patients with psoriasis are higher than normal, so the presence of subclinical active airway inflammation could be a risk factor linked to the possibility of developing COPD …”

“…Inflammation can further increase the amount of NO by implementing iNOS expression. Thus, fractional exhaled NO (FeNO) has been accepted in the literature as an indirect marker of airway inflammation, and is currently used in the clinical monitoring and management of asthma inflammation levels …”

Impaired Pulmonary Function in Patients with Psoriasis

“…The fraction of exhaled nitric oxide (FeNO) levels in COPD patients is affected by smoking and disease severity. FeNO elevation in psoriasis patients may increase the risk of COPD [13] . A recent study found that FeNO levels were elevated in patients with psoriasis, possibly reflecting subclinical airway inflammation.…”

Combined atmospheric oxidant capacity and increased levels of exhaled nitric oxide

“…We therefore designed a longitudinal panel study to explore the effects of O x on respiratory inflammation in a group of patients with chronic obstructive pulmonary disease (COPD) in Shanghai, China. Respiratory inflammation was evaluated using fractional exhaled nitric oxide (FeNO), a non-invasive biomarker commonly used in previous studies (Liu et al 2009, Malerba et al 2014.…”

“…The X-axis refers to the categorization; the Y-axis refers to the percent changes in FeNO. Abbreviations: FeNO, fractional exhaled nitric oxide; BMI, body mass index Malerba et al 2014)…”