Ion and fluid transport properties of small airways in cystic fibrosis.
BACKGROUND
Small airways constitute a major site of pathology in cystic fibrosis (CF) and provide most of the surface area of the conducting airways of the lung. Little is known, however, about the impact of CF on ion and fluid transport in small (bronchiolar) airways.


OBJECTIVE
To describe the ion and fluid transport properties of CF bronchiolar epithelium.


METHODS
Primary cultures of human bronchial and bronchiolar (non-CF and CF) epithelial cells were obtained. The bioelectric properties were studied in Ussing chambers and the airway surface liquid (ASL) height was measured with confocal microscopy.


RESULTS
Primary cultures of DeltaF508 CF bronchiolar epithelial cells displayed higher transepithelial resistance than non-CF cultures, whereas baseline short circuit current and amiloride-inhibitable short circuit current were similar in both preparations. The ASL height was significantly smaller in CF compared with non-CF preparations. In the presence of amiloride, addition of forskolin increased short circuit current in non-CF but not in CF bronchiolar cultures, and the ATP-induced increase in short circuit current was lower in CF than in non-CF cultures. Non-CF bronchiolar preparations displayed larger short circuit current and fluid secretion in responses to forskolin than non-CF bronchial preparations, suggesting that CFTR-dependent Cl(-) transport may play a more important role in the regulation of fluid transport in small airways than in large airways.


CONCLUSIONS
In CF small airways, defective Cl(-) secretion combined with unregulated (persistent) Na(+) absorption results in ASLdepletion.
Blouquit
Sabine
S
UPRES EA220, Pathology Department, and Clinical Research Unit, UFR Paris Ile de France Ouest, Université de Versailles Saint Quentin en Yvelines, Boulogne, France.
Regnier
Agathe
A
Dannhoffer
Luc
L
Fermanian
Christophe
C
Naline
Emmanuel
E
Boucher
Richard
R
Chinet
Thierry
T
D001834:Body Water / Q000187:drug effects / Q000378:metabolism*; D001980:Bronchi / Q000166:cytology; D002478:Cells, Cultured; D002712:Chlorides / Q000378:metabolism*; D005576:Colforsin / Q000494:pharmacology; D003550:Cystic Fibrosis / Q000378:metabolism* / Q000473:pathology; D017097:Electric Impedance; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D017136:Ion Transport; D018613:Microscopy, Confocal; D008875:Middle Aged; D012016:Reference Values
D002712:Chlorides; D005576:Colforsin