In vivo bicarbonate secretion by human esophagus

Area of Science:

• Gastroenterology
• Physiology

Background:

• Gastroesophageal reflux disease (GERD) is a common condition.
• The esophagus has defense mechanisms against acid reflux.

Purpose of the Study:

• To investigate the bicarbonate secretion capacity of the human esophagus in vivo.
• To determine if esophageal bicarbonate secretion contributes to acid neutralization.

Main Methods:

• A 10-cm segment of the lower esophagus was isolated in 10 healthy subjects.
• The segment was perfused with saline, and perfusate bicarbonate was measured.
• Salivary and aspirate amylase were measured to correct for saliva contamination.

Main Results:

• All 10 subjects demonstrated esophageal bicarbonate secretion.
• Secretion ranged from 10 to 274 microEq/30 min (average 78 microEq/30 min).
• Calculated neutralization capacity could raise pH from 2.5 to 6-7.

Conclusions:

• The human esophagus actively secretes bicarbonate.
• This secretion provides an additional defense mechanism against acid reflux damage.
• Esophageal bicarbonate enhances luminal acid clearance, protecting against GERD.