PhD Scientific Days 2022

Clinical Medicine VII. (Poster discussion will take place in the Aula during the Coffee Break)

Inflammatory and microbiological changes in the upper and lower airways in COPD

Text of the abstract

Introduction: Chronic obstructive pulmonary disease (COPD) is a common progressive respiratory disease associated with airway inflammation. Nitrative stress is an integral part of airway inflammation in COPD, and it can be monitored by measuring exhaled nitric oxide (NO) concentration. Besides the established role of lower airway inflammation in the pathomechanism, nasal inflammation can also be present, and upper airway symptoms may worsen lung symptoms and predispose to exacerbations. However, the role of nasal NO in the monitoring of COPD is unknown.
Aims: to assess the relationship between upper and lower airway NO levels in COPD and healthy control subjects, and to study the microbiological changes associated with acute exacerbations.
Methods: The measurement of NO concentrations was performed in 19 COPD (N=3 stable, N=13 acute exacerbation) and 37 healthy subjects using NOA280i. Fractional nitric oxide (FeNO) was measured at multiple exhalation rates (50-250 mL/s) and alveolar and bronchial NO production were calculated (Lazar Z et al., J Breath Res, 2018). Nasal NO was measured at 2 L/min aspiration rate. Microbiological assessments of sputum and nasopharyngeal swab specimens were carried out in all COPD patients either with culture or polymerase chain reaction (PCR) tests, or both.
Results: We found no difference in nasal NO outputs (median 470.9, interquartile range [IQR] 416.7-540.8 vs. 540 [410.3-609] nL/min, p=0.32) and bronchial NO flux (0.5 [0.17-0.94] vs. 0.93 [0.35-2.3] nL/s, p=0.10) between healthy subjects and COPD patients. FeNO50 (11.8 [6.7-17] vs. 16.1 [9.5-49] ppb, p=0.04) and alveolar NO concentrations (1.4 [0.5-3] vs. 7.1 [2.4-10.5] ppb, p<0.01) were elevated in the disease. There was no correlation between nasal and lower airway NO parameters (p>0.05). Increased nasal nitric oxide was associated with a higher probability of a positive nasopharyngeal PCR test (β=0.81, p<0.01) in COPD patients.
Conclusion: Our results suggest elevated small airway nitrative stress in COPD. The NO productions of lower and upper airways are not related. Upper airway infections may be associated with elevated nasal NO production.
Funding: our study was funded by the Hungarian Respiratory Foundation, the New National Excellence Program of the Ministry for Innovation and Technology (ÚNKP-21-3-II-SE-22), and by the SE250+ Excellence Fellowship program.