Inhaled Mannitol Improves the Hydration and Surface properties of Sputum in patients with Cystic Fibrosis

Chest. 2009 Oct 31. [Epub ahead of print]
Inhaled Mannitol Improves the Hydration and Surface properties of Sputum in patients with Cystic Fibrosis.

Daviskas E, Anderson SD, Jaques A, Charlton B.

Royal Prince Alfred Hospital, Respiratory and Sleep Medicine, 11 West, Missended Rd, Camperdown, Sydney, New South Wales, Australia, 2050, 61 2 9515 7410, 61 2 95158196, daviskas@med.usyd.edu.au.

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 A et al. CHEST 2008;133:1388-1396). The changes in the physical properties of sputum after a 2-week treatment with mannitol were investigated in the same CF subjects. M

ETHODS: Sputum was collected before and at the end of the 2-week treatment period from 28 CF subjects who participated in the double blind crossover study. Mannitol or placebo 420 mg was inhaled twice daily over 2-weeks. The solids content, surface tension, contact angle and viscoelasticity was measured.

RESULTS: Two-week treatment with mannitol reduced the solids from 7.3+/-3.0 to 5.7+/-3.0% (p=0.012), surface tension from 83.1+/-7.2 to 78.6+/-8.0 mN/m (p<0.039) 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>0.1). Placebo treatment had no significant effect on the sputum properties. The change in solids content correlated with the change in both FEV(1) (r(s)=-0.78, p=0.004) and FEF(25-75) (r(s)=-0.80, p=0.003) and the % change in surface tension and contact angle correlated with the % change in the FEV(1) (r(s)=-0.73, p=0.012 and r(s)=-0.63, p=0.03 respectively) in these subjects.

CONCLUSION: 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.