Endotoxin-induced arterial endothelial barrier dysfunction assessed by an in vitro model

Area of Science:

• Endothelial cell biology
• Vascular physiology
• Inflammation and immunology

Background:

• Endothelial permeability is crucial for regulating vascular function.
• Septic shock is characterized by widespread vascular leakage.
• The role of lipopolysaccharide (LPS) in endothelial dysfunction requires further elucidation.

Purpose of the Study:

• To investigate the effect of LPS on endothelial permeability in an in vitro model.
• To determine the temporal profile of LPS-induced endothelial permeability changes.
• To explore the involvement of the L-arginine-nitric oxide system in LPS-induced endothelial dysfunction.

Main Methods:

• Utilized an in vitro model using bovine aortic endothelial cells (BAEC) monolayers.
• Measured albumin transfer across BAEC monolayers to assess endothelial permeability.
• Administered varying concentrations of LPS and assessed its effects over time (2 h and 24 h).
• Investigated the impact of polymixin B (PMB), L-arginine analogues, and dexamethasone on LPS-induced permeability.
• Quantified nitric oxide production by BAEC following LPS exposure.

Main Results:

• LPS induced a concentration-dependent, biphasic increase in endothelial permeability.
• The permeability peaks occurred at 2 hours and 24 hours post-LPS exposure.
• Polymixin B (PMB) abolished both permeability peaks.
• N omega-monomethyl-L-arginine, N omega-nitro-L-arginine methyl ester, and dexamethasone did not affect LPS-induced permeability.
• LPS exposure did not stimulate nitric oxide production in BAEC.

Conclusions:

• LPS significantly increases endothelial permeability in a biphasic manner.
• The observed increase in endothelial permeability may contribute to vascular leakage in septic shock.
• The L-arginine-nitric oxide system does not appear to be involved in LPS-induced endothelial permeability.
• Polymixin B effectively mitigates LPS-induced endothelial barrier dysfunction.