Decreased exhaled nitric oxide levels in patients with mitochondrial disorders.
BACKGROUND
Nitric oxide (NO) deficiency may occur in mitochondrial disorders (MD) and can contribute to the pathogenesis of the disease. It is difficult and invasive to measure systemic nitric oxide. NO is formed in the lungs and can be detected in expired air. Currently, hand-held fractional exhaled nitric oxide (FeNO) measurement devices are available enabling a fast in-office analysis of this non-invasive test. It was postulated that FeNO levels might be reduced in MD.


METHODS
Sixteen subjects with definite MD by modified Walker criteria (4 to 30 years of age) and sixteen healthy control subjects of similar age, race and body mass index (BMI) underwent measurement of FeNO in accordance with the American Thoracic Society guidelines.


RESULTS
Sixteen patient-control pairs were recruited. The median FeNO level was 6.5 ppm (IQR: 4-9.5) and 10.5 ppm (IQR: 8-20.5) in the MD and control groups, respectively. In 13 pairs (81%), the FeNO levels were lower in the MD cases than in the matched controls (p=0.021). Eleven (69%) cases had very low FeNO levels (≤7ppm) compared to only 1 control (p=0.001). All cases with enzymatic deficiencies in complex I had FeNO ≤7ppm.


CONCLUSIONS
Single-breath exhaled nitric oxide recordings were decreased in patients with MD. This pilot study suggests that hand-held FeNO measurements could be an attractive non-invasive indicator of MD. In addition, measurement of FeNO could be used as a parameter to monitor therapeutic response in this population.
University of Texas Health Science Center at Houston (UTHealth), School of Medicine, Department of Pediatric Pulmonary, Houston, Texas, USA.
Ricardo A
RA
Mosquera
Cheryl L
CL
Samuels
Tomika S
TS
Harris
Aravind
A
Yadav
S Shahrukh
SS
Hashmi
Melissa S
MS
Knight
Mary Kay
MK
Koenig
FeNO; Mitochondrial disorder; NIOX MINO.; exhaled nitric oxide; modified walker criteria; walker criteria