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Role of ion transporters in the bile acid-induced esophageal injury.
- Source :
-
American journal of physiology. Gastrointestinal and liver physiology [Am J Physiol Gastrointest Liver Physiol] 2016 Jul 01; Vol. 311 (1), pp. G16-31. Date of Electronic Publication: 2016 May 19. - Publication Year :
- 2016
-
Abstract
- Barrett's esophagus (BE) is considered to be the most severe complication of gastro-esophageal reflux disease (GERD), in which the prolonged, repetitive episodes of combined acidic and biliary reflux result in the replacement of the squamous esophageal lining by columnar epithelium. Therefore, the acid-extruding mechanisms of esophageal epithelial cells (EECs) may play an important role in the defense. Our aim was to identify the presence of acid/base transporters on EECs and to investigate the effect of bile acids on their expressions and functions. Human EEC lines (CP-A and CP-D) were acutely exposed to bile acid cocktail (BAC) and the changes in intracellular pH (pHi) and Ca(2+) concentration ([Ca(2+)]i) were measured by microfluorometry. mRNA and protein expression of ion transporters was investigated by RT-PCR, Western blot, and immunohistochemistry. We have identified the presence of a Na(+)/H(+) exchanger (NHE), Na(+)/HCO3 (-) cotransporter (NBC), and a Cl(-)-dependent HCO3 (-) secretory mechanism in CP-A and CP-D cells. Acute administration of BAC stimulated HCO3 (-) secretion in both cell lines and the NHE activity in CP-D cells by an inositol triphosphate-dependent calcium release. Chronic administration of BAC to EECs increased the expression of ion transporters compared with nontreated cells. A similar expression pattern was observed in biopsy samples from BE compared with normal epithelium. We have shown that acute administration of bile acids differently alters ion transport mechanisms of EECs, whereas chronic exposure to bile acids increases the expression of acid/base transporters. We speculate that these adaptive processes of EECs represent an important mucosal defense against the bile acid-induced epithelial injury.<br /> (Copyright © 2016 the American Physiological Society.)
- Subjects :
- Aged
Aged, 80 and over
Barrett Esophagus pathology
Bile Acids and Salts metabolism
Calcium metabolism
Cell Line
Chloride-Bicarbonate Antiporters metabolism
Epithelial Cells metabolism
Epithelial Cells pathology
Esophageal Mucosa metabolism
Esophageal Mucosa pathology
Female
Gene Expression Regulation
Humans
Hydrogen-Ion Concentration
Inositol Phosphates metabolism
Ion Transport
Male
Membrane Transport Proteins genetics
Metaplasia
Middle Aged
Sodium-Bicarbonate Symporters metabolism
Sodium-Hydrogen Exchangers metabolism
Time Factors
Barrett Esophagus metabolism
Bile Acids and Salts toxicity
Epithelial Cells drug effects
Esophageal Mucosa drug effects
Membrane Transport Proteins metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1522-1547
- Volume :
- 311
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- American journal of physiology. Gastrointestinal and liver physiology
- Publication Type :
- Academic Journal
- Accession number :
- 27198194
- Full Text :
- https://doi.org/10.1152/ajpgi.00159.2015