Parameters influencing intestinal epithelial permeability and microparticle uptake in vitro

Area of Science:

• Gastroenterology
• Cell Biology
• Biophysics

Background:

• Enterocyte tight junctions (TJs) regulate paracellular transport in the intestinal epithelium.
• Understanding microparticle uptake mechanisms is vital for drug delivery and understanding intestinal barrier function.

Purpose of the Study:

• To investigate the role of enterocyte TJs in the in vivo uptake of 2 microm latex microparticles.
• To utilize a Caco-2 cell model to simulate and analyze microparticle-epithelium interactions.

Main Methods:

• Caco-2 cells cultured on porous membranes were used to measure epithelial permeability via transepithelial resistance (TER).
• Microscopy quantified latex microparticle numbers in various epithelial compartments.
• Simulated peristaltic movement (bolus removal) was employed to study dynamic TJ responses.

Main Results:

• Apical particle exposure initially tightened TJs, followed by loosening in treated groups.
• Simulated bolus removal induced significant TJ loosening.
• Increased particle exposure time correlated with higher adsorbed and intraepithelial particle numbers.
• TER changes correlated with particle numbers, suggesting TJ loosening is key to microparticle uptake.

Conclusions:

• Enterocyte TJ dynamics are critical for microparticle uptake.
• The Caco-2 cell model effectively approximates in vivo microparticle uptake and allows for microenvironmental manipulation.
• Findings provide a basis for understanding and potentially modulating intestinal barrier function for therapeutic purposes.