Transendothelial transfer of macromolecules in vitro

Area of Science:

• Cell biology
• Physiology
• Biophysics

Background:

• Studying transendothelial transfer of macromolecules is challenging due to complex in vivo models.
• Endothelial cells form a critical barrier regulating substance passage.
• Understanding albumin transport is vital for physiological processes.

Purpose of the Study:

• To develop and characterize an in vitro model for studying transendothelial macromolecule transfer.
• To investigate the mechanism and directionality of albumin transport across an endothelial monolayer.
• To identify factors influencing transendothelial albumin flux.

Main Methods:

• Cultured porcine pulmonary artery endothelial cells on permeable supports.
• Utilized electrical cell-substrate impedance sensing (ECIS) to assess monolayer integrity.
• Quantified albumin transfer across the endothelial monolayer under varying conditions.

Main Results:

• Established a functional endothelial monolayer with tight junction-like structures.
• Demonstrated asymmetric albumin transfer, with higher flux from interstitium to lumen.
• Observed active, concentration-dependent, and saturable albumin transport sensitive to NaCN.
• Identified saturation of interstitial to luminal transfer at 725 microM albumin.

Conclusions:

• The in vitro model effectively mimics in vivo endothelial barrier function for transport studies.
• Transendothelial albumin transport exhibits active, asymmetric, and saturable characteristics.
• This model provides a valuable tool for dissecting complex transendothelial transport mechanisms.