title: Inhaled mannitol improves the hydration and surface properties of sputum in patients with cystic fibrosis.
abstract: BACKGROUND
  The airway mucus in patients with cystic fibrosis (CF) is dehydrated and adhesive and accumulates in the airways, resulting in chronic inflammation, infection, and progressive loss of lung function. Inhaled mannitol improves mucus clearance and, when administered over 2 weeks, it improves lung function in CF (Jaques et al. Chest. 2008;133(6):1388-1396). The changes in the physical properties of sputum after a 2-week treatment with mannitol were investigated in the same subjects with CF.
  
  
  METHODS
  Sputum was collected before and at the end of the 2-week treatment period from 28 subjects with CF who participated in the double-blind crossover study. Mannitol or placebo 420 mg bid was inhaled over 2 weeks. The solids content, surface tension, contact angle, and viscoelasticity were measured.
  
  
  RESULTS
  Two-week treatment with mannitol reduced the solids from 7.3% +/- 3.0% to 5.7% +/- 3.0% (P = .012), surface tension from 83.1 +/- 7.2 to 78.6 +/- 8.0 mN/m (P < .039), and contact angle from 52.4 +/- 7.7 to 47.9 +/- 7.3 degrees. There was no significant change in the viscoelastic properties of sputum (P > .1). Placebo treatment had no significant effect on the sputum properties. The change in solids content correlated with the change in both FEV(1) (r = -0.78, P = .004) and forced expiratory flow in the middle half of the FVC (r = -0.80, P = .003), and the percentage change in surface tension and contact angle correlated with the percentage change in the FEV(1) (r = -0.73, P = .012 and r = -0.63, P = .03, respectively) in these subjects.
  
  
  CONCLUSIONS
  Treatment with inhaled mannitol over 2 weeks improved the hydration and surface properties of sputum in patients with CF. This effect was sustained and correlated with airway function changes.
  
  
  BACKGROUND
  clinicaltrials.gov; Identifier: NCT00455130.
authors.affiliation: Department of Respiratory and Sleep Medicine, Royal Prince Alfred Hospital, 11 West, Missenden Rd, Camperdown, Sydney, NSW 2050, Australia. daviskas@med.usyd.edu.au
authors.forename: Evangelia
authors.initials: E
authors.lastname: Daviskas
authors.forename: Sandra D
authors.initials: SD
authors.lastname: Anderson
authors.forename: Anna
authors.initials: A
authors.lastname: Jaques
authors.forename: Brett
authors.initials: B
authors.lastname: Charlton
mesh_terms: D000280:Administration, Inhalation; D000328:Adult; D002648:Child; D018592:Cross-Over Studies; D003550:Cystic Fibrosis / Q000188:drug therapy* / Q000378:metabolism*; D004311:Double-Blind Method; D004548:Elasticity / Q000502:physiology; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008168:Lung / Q000503:physiopathology; D008353:Mannitol / Q000008:administration & dosage / Q000627:therapeutic use*; D009093:Mucus / Q000502:physiology; D013183:Sputum / Q000378:metabolism*; D014797:Vital Capacity / Q000502:physiology
chemical_list: D008353:Mannitol