title: Low alveolar and bronchial nitric oxide in severe uncomplicated obesity.
abstract: BACKGROUND
  Fractional concentration of exhaled nitric oxide (FeNO) is a recognized biomarker of the lower respiratory tract, where it is produced by the proximal conducting airways and the expansible peripheral bronchoalveolar compartment. We have previously shown that large increase in body mass decreases FeNO. Here we evaluated bronchial and alveolar components of the NO output of the lower respiratory tract in subjects with severe uncomplicated obesity (OB).
  
  
  METHODS
  Fifteen OB subjects (BMI 45.3 ± 5.6 kg/m(2)), 15 healthy controls (HC) (BMI 22.4 ± 2.4 kg/m(2)) and 10 obese subjects who experienced weight loss after bariatric surgery (OBS) (BMI 31.2 ± 3.4 kg/m(2)), were examined. Anthropometry and respiratory lung tests were performed. Exhaled NO was assessed using multiple single-breath NO analysis at different constant expiratory flow rates. From the fractional NO concentration measured at each flow-rate, the total NO flux between tissue and gas phase in the bronchial lumen (J'awNO), and the alveolar NO concentration (CANO) were extrapolated.
  
  
  RESULTS
  Measured FeNO levels at 50 mL/s were lower in OB compared with HC and OBS (11.6 ± 2.8 ppb, 18.0 ± 4.1 ppb and 17.6 ± 2.9 ppb, respectively, p < 0.05). In OB, both J'awNO and CANO resulted significantly lower than OBS and HC values.
  
  
  CONCLUSIONS
  Respiratory NO output is decreased in severe uncomplicated obesity for the reduction of both large/central airway maximal NO flux and alveolar NO concentration. The pathophysiological relevance of airway NO abnormalities in severe obese phenotype remains to be investigated.
authors: Section of Respiratory Medicine, S. Maria della Pietà Hospital, Casoria, Naples, Italy. Electronic address: mauromaniscalco@hotmail.com.
authors: Mauro
authors: M
authors: Maniscalco
authors: Section of Respiratory Medicine, S. Maria della Pietà Hospital, Casoria, Naples, Italy.
authors: Anna
authors: A
authors: Zedda
authors: Section of Respiratory Medicine, S. Maria della Pietà Hospital, Casoria, Naples, Italy.
authors: Stanislao
authors: S
authors: Faraone
authors: Department of Surgery, S. Maria della Pietà Hospital, Casoria, Naples, Italy.
authors: Stefano
authors: S
authors: Cristiano
authors: Department of Respiratory Medicine, Monaldi Hospital, University Federico II of Naples, Italy.
authors: Matteo
authors: M
authors: Sofia
authors: Institute of Biomolecular Chemistry, National Research Council, Pozzuoli, Naples, Italy.
authors: Andrea
authors: A
authors: Motta
mesh_terms: D000328:Adult; D050110:Bariatric Surgery; D001944:Breath Tests; D045853:Exhalation; D005260:Female; D006801:Humans; D007558:Italy; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism*; D009767:Obesity, Morbid / Q000378:metabolism* / Q000503:physiopathology; D011237:Predictive Value of Tests; D011650:Pulmonary Alveoli / Q000378:metabolism*; D012016:Reference Values; D012720:Severity of Illness Index; D014797:Vital Capacity; D015431:Weight Loss / Q000502:physiology
chemical_list: D009569:Nitric Oxide
keywords: Airway; BMI; Exhaled nitric oxide; Lung; Obesity