Exhaled NO and iNOS expression in sputum cells of healthy, obese and OSA subjects

Abstract

Background. Obstructive sleep apnoea (OSA) is associated with airways inflammation; a key role in this regard seems to be played by nitric oxide (NO). The aim of this study was to measure exhaled NO and expression of its enzyme, the inducible nitric oxide synthase (iNOS) in cells of induced sputum in OSA patients and in obese subjects without sleep apnoea and to correlate these inflammatory markers with severity of OSA.

Exhaled Breath Analysis and Sleep

“…6 On the contrary, in adult patients, it was demonstrated that eNO was not always increased in patients with OSAS, although even in obese subjects without sleep disorders a positive correlation was observed between eNO and body mass index (BMI) as well as with apnea hypopnea index (AHI). 7,8 This finding suggests that obesity could increase not only systemic inflammation but also pulmonary inflammation. Although the relation between obesity and systemic inflammation is well known, the link between obesity and pulmonary inflammation still remains unclear.…”

Long-Term Continuous Positive Airway Pressure Therapy Normalizes High Exhaled Nitric Oxide Levels in Obstructive Sleep Apnea

“…4,[23][24] The results we observed in our study are consistent with the current evidence showing elevated cytokines and inflammatory markers in exhaled breath as well as upper airway tissues of OSA patients. 4,[9][10][11][12][13][14][15][16][17]23,[25][26][27][28] Salerno et al and Devouassoux et al detected increased neutrophils and reduced macrophages in the induced sputum of OSA patients. 27,28 The latter study also observed a concurrent higher interleukin-8 concentration in the induced sputum specimen of these patients.…”

“…Post-vs. pre-sleep FENO was signifi cantly increased in one study 7 but unchanged in another. 9 The FENO correlated with the apnea-hypopnea in- dex (AHI) in one study 11 but not in another. 8 Finally, few studies have assessed the impact of CPAP on FENO, generally showing a decrease in FENO with CPAP.…”

“…5,6 Prior studies that have evaluated the FENO levels in OSA have shown inconsistent results. [7][8][9][10][11][12][13][14][15][16][17] Specifi cally, studies have shown no difference, 8,10 mild increase, 13 or signifi cant increases in FENO 7,9,11,12,14,16,17 compared to controls. Post-vs. pre-sleep FENO was signifi cantly increased in one study 7 but unchanged in another.…”

“…[7][8][9][10][11][12][13][14][15][16][17] Part of the problem could have been patient selection or the use of old technology and methodology. With the latest generation portable FENO analyzer, we demonstrated a rise in FENO levels following sleep in adult OSA patients reflecting increased UAWI that were not present in healthy controls with normal airways.…”