Acetaldehyde-induced increase in paracellular permeability in Caco-2 cell monolayer

Area of Science:

• Gastroenterology
• Hepatology
• Toxicology

Background:

• Alcoholic liver disease pathogenesis involves endotoxin-mediated liver injury.
• Elevated endotoxin levels in alcoholics may stem from gut dysbiosis or increased intestinal permeability.
• Understanding the direct effects of alcohol metabolites on intestinal barrier function is critical.

Purpose of the Study:

• To investigate the impact of ethanol and acetaldehyde on intestinal paracellular permeability.
• To differentiate the effects of ethanol versus its metabolite, acetaldehyde, on the gut barrier.

Main Methods:

• Utilized Caco-2 cell monolayers as a model for intestinal epithelium.
• Assessed paracellular permeability via transepithelial electrical resistance (TER), dilution potential, and mannitol flux.
• Administered ethanol directly and acetaldehyde via vapor phase or an acetaldehyde generating system (AGS).

Main Results:

• Ethanol exposure did not significantly alter paracellular permeability.
• Acetaldehyde exposure led to a time- and dose-dependent increase in paracellular permeability, indicated by reduced TER, altered dilution potential, and increased mannitol flux.
• The effects of acetaldehyde were reversible upon its removal, and AGS-induced changes were blocked by an alcohol dehydrogenase inhibitor.

Conclusions:

• Acetaldehyde, not ethanol, is responsible for reversibly increasing paracellular permeability in intestinal epithelial cells.
• These findings highlight acetaldehyde's role in compromising gut barrier integrity in the context of alcohol consumption.
• The reversible nature of acetaldehyde's effect suggests potential therapeutic targets for mitigating alcohol-induced gut barrier dysfunction.