The effects of fluticasone propionate on nasal epithelial potential difference.
BACKGROUND
Human airway epithelium maintains homeostasis of the fluid and salt composition at the airway surface by a regulated transport of sodium and chloride ions. The volume and composition of airway surface liquid have been shown to be important in the pathogenesis of cystic fibrosis, nasal inflammatory disease, and nasal polyposis. The presence of functional epithelial sodium and chloride channels in the airway epithelium can be evaluated electrically by measuring the voltage across the nasal epithelium (Vt). Because fluticasone propionate is commonly used to treat nasal inflammatory diseases, we tested its effect on the nasal ion transport.


METHODS
A single-blind prospective trial was performed on 12 healthy volunteers. Subjects were randomized to receive either fluticasone propionate or normal saline nasal spray twice daily for 2 weeks. We measured the nasal voltage at baseline, days 3 and 14, and 2 weeks after cessation of treatment. The basal voltage, the change in voltage after perfusion with amiloride (sodium channel blocker), and the change in voltage after perfusion with isoproterenol in a low-chloride buffer (chloride channel activator) were recorded. Saccharin clearance times were measured also.


RESULTS
Two-week treatment with fluticasone propionate resulted in a significant increase in the change in Vt after perfusion with amiloride. There was no significant change in the group treated with normal saline. These findings also were observed on day 3 and were reversed completely after the 2-week washout period The increase in amiloride-sensitive Vt did not result in a decrease in mucociliary clearance.


CONCLUSIONS
This study suggests that one effect of fluticasone propionate use on nasal mucosa in normal volunteers is increased epithelial sodium absorption.
Department of Otolaryngology-Head and Neck Surgery, University of Iowa, Iowa City, USA.
Scott M
SM
Graham
Shaun N
SN
Scott
Janice
J
Launspach
Joseph
J
Zabner
D000281:Administration, Intranasal; D000328:Adult; D000584:Amiloride / Q000008:administration & dosage; D000730:Androstadienes / Q000494:pharmacology*; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D001692:Biological Transport / Q000187:drug effects; D004334:Drug Administration Schedule; D004594:Electrophysiology; D000068298:Fluticasone; D005938:Glucocorticoids; D006801:Humans; D008875:Middle Aged; D009079:Mucociliary Clearance / Q000187:drug effects*; D009297:Nasal Mucosa / Q000187:drug effects*; D011336:Probability; D011446:Prospective Studies; D012016:Reference Values; D016037:Single-Blind Method
D000730:Androstadienes; D000893:Anti-Inflammatory Agents; D005938:Glucocorticoids; D000584:Amiloride; D000068298:Fluticasone