Chromatographic demonstration of reversible changes in endothelial permeability

Area of Science:

• Biomedical Engineering
• Cell Biology
• Pharmacology

Background:

• Endothelial monolayer permeability is crucial for physiological processes and drug delivery.
• Existing in vitro methods often lack accuracy or fail to reflect in vivo conditions.
• Understanding permeability modulation is key to developing targeted therapies.

Purpose of the Study:

• To introduce a new in vitro method for measuring endothelial monolayer diffusional permeability.
• To investigate the effects of various agents on endothelial permeability.
• To validate the method's reproducibility and relevance to in vivo permeability.

Main Methods:

• Developed a cell-column chromatography technique using endothelial cells on microcarrier beads.
• Applied tracers of varying molecular weights to determine permeability using the Sangren-Sheppard model.
• Administered agents like isoproterenol, propranolol, dibutyryl cyclic adenosine monophosphate (cAMP), and cytochalasin D to assess permeability modulation.

Main Results:

• The method provided reproducible permeability measurements for tracers from water to polyethylene glycol.
• Isoproterenol and dibutyryl cAMP decreased permeability, effects reversed by propranolol or removal of dibutyryl cAMP, respectively.
• Cytochalasin D significantly increased permeability, an effect that was reversible.

Conclusions:

• Cell-column chromatography is a powerful and reproducible in vitro method for assessing endothelial permeability.
• The study demonstrates the method's utility in characterizing permeability changes induced by pharmacological agents.
• Findings provide a foundation for further research into endothelial barrier function and drug interactions.