Safety assessment of inhaled xylitol in subjects with cystic fibrosis

BackgroundXylitol is a 5-carbon sugar that can lower the airway surface salt concentration, thus enhancing innate immunity. We tested the safety and tolerability of aerosolized iso-osmotic xylitol in subjects with cystic fibrosis.MethodsIn this pilot study, 6 subjects with cystic fibrosis and an FEV1 > 60% predicted underwent a baseline spirometry followed by exposures to aerosolized saline (10 ml) and 5% xylitol (10 ml). Serum osmolarity and electrolytes were measured at baseline and after xylitol exposure. Spirometry, oxygen saturation and respiratory symptom questionnaire using visual analog scale were tested at baseline and after each exposure. Sputum for cytokine analysis was collected after saline and xylitol nebulizations.ResultsThere was no change in FEV1 after xylitol exposure compared with baseline or normal saline exposure (p = 0.19). Laboratory values and respiratory symptoms were not affected by xylitol inhalation. The mean IL-8 level in the sputum was similar with saline and xylitol exposures (3.5 ± 0.5 vs. 3.5 ± 0.6 ng/ml).ConclusionsA single dose inhalation of aerosolized iso-osmotic xylitol was well tolerated by subjects with cystic fibrosis. Future studies of long term safety are required.