Study objectives: To investigate whether nitric oxide (NO) metabolites would be reduced in children affected by primary ciliary dyskinesia (PCD).
Design: Single-center observational study.
Patients: Fifteen children with PCD (seven boys; mean [± SEM] age, 10.3 ± 0.7 years; mean FEV1, 73 ± 2.1% predicted) were recruited along with 14 healthy age-matched subjects (seven boys; mean age, 11.5 ± 0.4 years; mean FEV1, 103 ± 5% predicted).
Interventions: We assessed the levels of nitrite (NO2−), NO2−/NO3− (NO2−/NO3−), and S-nitrosothiol in exhaled breath condensate, exhaled NO, and nasal NO from children with PCD compared to those in healthy children.
Measurements and results: The mean exhaled and nasal NO levels were markedly decreased in children with PCD compared to those without PCD (3.2 ± 0.2 vs 8.5 ± 0.9 parts per billion [ppb], respectively [p < 0.0001]; 59.6 ± 12.2 vs 505.5 ± 66.8 ppb, respectively [p < 0.001]). Despite the lower levels of exhaled NO in children with PCD, no differences were found in the mean levels of NO2− (2.9 ± 0.4 vs 3.5 ± 0.3 μM, respectively), NO2−/NO3− (35.2 ± 5.0 vs 34.3 ± 4.5 μM, respectively), or S-nitrosothiol (1.0 ± 0.2 vs 0.6 ± 0.1 μM, respectively) between children with PCD and healthy subjects.
Conclusion. These findings suggest that NO synthase activity may not be decreased as much as might be expected on the basis of low exhaled and nasal NO levels.