Transepithelial leak in Barrett's esophagus

Area of Science:

• Gastroenterology
• Cell Biology
• Molecular Biology

Background:

• Barrett's metaplasia is a complication of chronic gastroesophageal reflux disease.
• The integrity of the esophageal epithelial barrier is crucial for preventing reflux-induced damage.
• Understanding paracellular permeability is key to evaluating esophageal barrier function.

Purpose of the Study:

• To investigate paracellular transepithelial permeability to small nonelectrolytes in Barrett's metaplasia.
• To determine if Barrett's esophagus exhibits a leak to sucrose.
• To analyze the expression of tight junction proteins in Barrett's metaplasia.

Main Methods:

• Oral administration of sucrose as a probe of gastrointestinal permeability.
• Collection and analysis of overnight urine samples for sucrose concentration.
• High-performance liquid chromatography (HPLC) for sucrose quantification.
• Analysis of claudin tight junction protein expression in endoscopic biopsy samples.

Main Results:

• Patients with Barrett's esophagus demonstrated a threefold greater transepithelial leak of sucrose compared to controls.
• This leak was also significantly higher than in patients with gastroesophageal reflux disease without mucosal complications.
• Barrett's metaplasia showed increased claudin-2 and claudin-3 expression but decreased claudin-1 and claudin-5 expression compared to normal esophageal mucosa.

Conclusions:

• Barrett's metaplasia is characterized by increased paracellular permeability to small nonelectrolytes.
• Altered expression of specific claudin tight junction proteins contributes to the compromised esophageal barrier in Barrett's esophagus.
• These findings highlight a significant defect in the tight junction barrier in Barrett's metaplasia.