The objective of this study is to develop a new aerosol-based technique for quantifying
liquid absorption in the airways of subjects with cystic fibrosis(CF) that can be used to
help develop new therapies. In CF, mutations in the CF gene result in dysfunction of the
Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) ion channel on the cells that
line the airway epithelium, causing improper fluxes of ions such as sodium, chloride, and
bicarbonate. The so called "low volume" hypothesis of CF pathogenesis contends that abnormal
absorption of ions from the airways causes excessive absorption of liquid, resulting in an
airway surface liquid layer that is dehydrated and difficult to clear. Here we are trying to
develop a means of measuring liquid absorption from the airways so that therapies that would
propose to correct this basic defect of CF lung disease can be effectively tested.
- Cystic fibrosis subjects and healthy controls
- Age ≥ 18 years
- Diagnosis of cystic fibrosis as determined by sweat test or genotype and clinical
symptoms (CF subjects)
- Clinically stable as determined by the investigator (pulmonologist)
- Reactive airways disease
- Tobacco smokers (regular smoking within 6 months of enrollment)
- Positive urine pregnancy test on the day of testing
- FEV1p value of < 50%
- SaO2 < 92%, or if they require supplemental oxygen.
- Subjects performing other radioisotope studies within the last 2 weeks will be
- Healthy subjects with any history of lung disease will be excluded.
- Women currently breastfeeding
- Subjects not willing to stop treatments with inhaled hypertonic saline for 48 hours
in advance of the study.