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Airway nitric oxide in asthmatic children and patients with cystic fibrosis
J Dötsch1, S Demirakça, H G Terbrack
1Dept of Pediatrics and Neonatology, Lustug-Liebig University of Giessen, Germany.
Insights
Asthmatic children exhale higher nitric oxide (NO) levels than controls, while cystic fibrosis patients show reduced nasal NO. Ambient NO influences exhaled NO, but neither correlates with lung function tests.
Area of Science:
- Respiratory Medicine
- Biochemistry
- Pediatrics
Background:
- Nitric oxide (NO) plays a role in respiratory health.
- Asthma and cystic fibrosis (CF) are chronic respiratory conditions affecting children and adults.
- Understanding NO levels in these conditions can provide insights into disease mechanisms.
Purpose of the Study:
- To evaluate the effects of asthma and cystic fibrosis on nitric oxide (NO) concentrations in the respiratory tract.
- To compare NO levels in orally exhaled air and nasal gas samples between asthmatic patients, CF patients, and healthy controls.
- To investigate the correlation between NO concentrations and pulmonary function tests.
Main Methods:
- NO concentrations were measured in orally exhaled air and nasal gas samples from 90 asthmatic patients, 67 CF patients, and 68 controls.
- Chemiluminescence was used to measure NO levels.
- NO concentrations were correlated with vital capacity, forced expiratory volume in one second (FEV1), and specific airway resistance.
Main Results:
- Asthmatic patients exhaled higher NO concentrations than CF patients and controls when ambient NO was 0 ppb.
- Nasal NO concentrations were significantly lower in CF patients compared to controls and asthmatics.
- No significant relationship was found between nasal or oral NO levels and pulmonary function tests.
Conclusions:
- Ambient NO levels can influence NO concentrations in orally exhaled air.
- Asthmatic children, similar to adults, exhibit elevated exhaled NO.
- Reduced nasal NO in CF patients may indicate epithelial damage or impaired NO diffusion.
Abstract:
We evaluated the effects of asthma and cystic fibrosis on nitric oxide (NO) concentrations in the respiratory tract. NO levels in orally exhaled air and nasal gas samples were studied in 90 asthmatic patients (4-14 yrs), 67 patients with cystic fibrosis (CF) (5-32 yrs), and 68 controls (4-34 yrs). NO concentrations measured by chemiluminescene were correlated with the patient's vital capacity, forced expiratory volume in one second (FEV1) and specific airway resistance. In all groups, NO concentrations in orally-exhaled air correlated with the inhaled ambient NO (r = 0.85-0.91). At an ambient NO concentration of 0 parts per billion (ppb), asthmatic patients exhaled air with higher NO concentrations than cystic fibrosis patients and controls (8.0 +/- 6.1 ppb (n = 33); 4.9 +/- 2.6 ppb (n = 23); and 3.0 +/- 2.5 ppb (n = 37); respectively; p < 0.001). Similar results were obtained for ventilation-adjusted orally-exhaled NO. Nasal NO concentrations were lower in patients with CF (23 +/- 17 ppb) than in controls and asthmatics (96 +/- 47 and 103 +/- 64 ppb; p < 0.001). There was no relationship between nasal or oral NO and pulmonary function tests. Our results suggest that ambient NO levels influence NO concentrations in orally-exhaled air. Like adults, asthmatic children exhale more NO than their controls. Reduced nasal NO concentrations in patients with cystic fibrosis may reflect chronic epithelial cell damage or an increased mucosal barrier impeding NO diffusion into the airway.