Fraction of exhaled nitric oxide measurement as a biomarker in asthma and COPD compared with local and systemic inflammatory markers

Abstract

Background: Asthma and COPD are characterized by chronic airway inflammation that results in chronic airway obstruction which is reversible in asthma and non-reversible or partially reversible in COPD. The differential diagnosis between reversible or irreversible airflow obstruction due to asthma or COPD is important in clinical practice because the prognosis and the response to treatment of the two diseases are different. Nitric oxide (NO) is produced by many cells within the respiratory tract. Endogenous NO may play an important signaling role in the physiological control of airway function and in the pathophysiology of airway diseases. Measurement of airway inflammation by means of FENO may be useful and convenient for asthma diagnosis, particularly when bronchial challenges and/or spirometric maneuvers cannot be correctly performed. The increase in the percentage of peripheral blood and sputum eosinophils was found in patients with asthma that correlated with the clinical severity of asthma and pulmonary function. Elevated levels of C-reactive protein (CRP) are established in COPD but, in asthma, the results have been inconsistent. The aim of the present study was to evaluate differences in local (airway) and systemic inflammatory markers among primary care patients with asthma and COPD using simple, rapid and easy to do tests.Subjects and methods: One hundred and fifty patients and thirty control subjects were included in this study. They were divided into three groups, ninety asthmatic patients diagnosed clinically and physiologically as reversible airway obstruction (group I). Sixty COPD patients diagnosed by clinical, physiological and laboratory tests to have irreversible or partially reversible airway obstruction (group II). The third group is the control group with no airway obstruction (NAO) including thirty subjects. Pulmonary function tests, FENO, hs-CRP, blood and sputum eosinophil percentages were done to all subjects.Results: FENO was positively correlated with all inflammatory markers in the asthmatic group with highly significant differences (p 6 .001) and negatively correlated with age, BMI and PFTs. In

Exhaled nitric oxide in patients with chronic obstructive pulmonary disease: a systematic review and meta-analysis

“…The sample size across studies varied from 21 to 212, with a total number of 1,669. The majority of studies were from Europe, 10 – 12 , 15 , 18 – 20 , 22 , 23 , 26 – 30 , 33 with 1 study from Australia, 17 1 study from America, 13 2 studies from Africa, 21 , 32 and 5 studies from Asia. 14 , 16 , 24 , 25 , 31 In terms of diagnosis of COPD, 9 studies used doctor-diagnosis, 13 , 15 , 17 , 21 , 23 , 29 , 31 , 32 8 studies used GOLD guideline, 10 , 12 , 14 , 18 , 22 , 24 , 26 , 30 , 33 2 applied American Thoracic Society criteria, 11 , 16 2 applied European Respiratory Society criteria, 20 , 27 2 applied British Thoracic Society guidelines, 19 , 28 and 1 applied Chinese Medical Association guidelines.…”

The Fraction Exhaled Nitric Oxide as a Biomarker of Asthma Control

“…25 The measurement of exhaled nitric oxide is applicable in real-life situations because of the following features: the measurement is very easily performed, compared with bronchial biopsy or eosinophil counts in sputum; it is non-invasive; and it is positively correlated with other inflammatory markers. 28 For this reason, the American Thoracic Society recommends measuring the FeNO level to monitor airway inflammation in clinical practice, 10 and the American College of Allergy, Asthma and Immunology (Arlington Heights, IL, USA) and the American Academy of Allergy, Asthma and Immunology (Milwaukee, WI, USA) support these recommendations. 29 The self-reported regular use of inhaled corticosteroid of 43.2% in this study was in agreement with the literature, as adherence with asthma treatment measures approximately 30%-50%.…”

Investigating Fractional Exhaled Nitric Oxide in Chronic Obstructive Pulmonary Disease (COPD) and Asthma-COPD Overlap (ACO): A Scoping Review

“…Major criteria included history of asthma and bronchodilator response of ≥15% and 400 mL; minor criteria consisted of history of hay fever, bronchodilator responses to of ≥12% and 200 mL, and blood eosinophils ≥5%, e) One study considered high levels of fractional exhaled nitric oxide (FENO > 35 ppb) or immunoglobulin E (IgE ≥ 173 IU/mL) in diagnosed COPD as markers of ACO candidate (20), f) One study (33) defined ACO according to the GINA-GOLD joint document (updated 2015) (39), g) One study (36) defined ACO according to the GINA-GOLD joint document 2014 (40). Sputum eosinophilia/elevated sputum eosinophils was defined as sputum eosinophil count ≥ 2.5% (37) or ≥ 3% (16) or > 3% (23) or no definition (2,7,8,11,19,30,34,35,38). Elevated blood eosinophils was defined as blood eosinophil count ≥ 1% (37) or ≥200 eosinophils•μL −1 (35) or no definition (11,19).…”

“…Sputum eosinophilia/elevated sputum eosinophils was defined as sputum eosinophil count ≥ 2.5% (37) or ≥ 3% (16) or > 3% (23) or no definition (2,7,8,11,19,30,34,35,38). Elevated blood eosinophils was defined as blood eosinophil count ≥ 1% (37) or ≥200 eosinophils•μL −1 (35) or no definition (11,19). Treatment response was defined as an increase in FEV1≥ 200mL (5) or > 200mL (14) or >12% and >200 mL (9,16).…”