title: Nasal and exhaled nitric oxide is reduced in adult patients with cystic fibrosis and does not correlate with cystic fibrosis genotype.
abstract: OBJECTIVE
  Inducible nitric oxide synthase (iNOS) is upregulated in a number of inflammatory lung conditions, and exhaled nitric oxide (NO) concentration is increased. However, previous studies in children with cystic fibrosis (CF) have shown that exhaled NO is reduced. The purpose of this investigation was to study exhaled NO concentration in adults with CF, and to investigate the effect of CF genotype and respiratory tract infection on this measurement.
  
  
  METHODS
  Exhaled and nasal NO levels were measured in 54 adult CF subjects and 37 healthy nonsmoking age-matched subjects using a chemiluminesence analyzer. Spirometry (FEV(1) and FVC), CF genotype, and bacterial colonization were also recorded.
  
  
  METHODS
  This study was conducted at a national CF center.
  
  
  RESULTS
  The mean age of patients was 26.9 years, and the mean FEV(1) was 50.5% predicted (range, 17 to 104%). Nasal NO in the CF patients (mean, 520 parts per billion [ppb]; confidence interval [CI], 452 to 588) was significantly lower (p < 0.001) than in control subjects (987 ppb; CI, 959 to 1,015). Exhaled NO was significantly lower (p < 0. 001) in CF patients (5.0 ppb; CI, 4.1 to 6.1) than in control subjects (7.3 ppb; CI, 6.8 to 7.8). FEV(1) did not correlate with nasal or exhaled NO. No association was observed between genotype and NO values or colonization with Pseudomonas aeruginosa.
  
  
  CONCLUSIONS
  Despite the airway inflammation that is characteristic of CF, both nasal and exhaled NO were reduced. There was no association with genotype or infection status. As NO has bacteriostatic effects and may augment mucociliary clearance, this observation may be of clinical importance.
authors.affiliation: Department of Cystic Fibrosis, Royal Brompton and Hariefiled NHS Trust, London, UK.
authors.forename: S R
authors.initials: SR
authors.lastname: Thomas
authors.forename: S A
authors.initials: SA
authors.lastname: Kharitonov
authors.forename: S F
authors.initials: SF
authors.lastname: Scott
authors.forename: M E
authors.initials: ME
authors.lastname: Hodson
authors.forename: P J
authors.initials: PJ
authors.lastname: Barnes
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers; D001944:Breath Tests; D003550:Cystic Fibrosis / Q000235:genetics* / Q000378:metabolism*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics; D006801:Humans; D008875:Middle Aged; D009154:Mutation; D009297:Nasal Mucosa / Q000378:metabolism*; D009569:Nitric Oxide / Q000032:analysis / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000172:deficiency; D052247:Nitric Oxide Synthase Type II; D011379:Prognosis
chemical_list: D015415:Biomarkers; C505032:CFTR protein, human; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D009569:Nitric Oxide; C496319:NOS2 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II