Site-dependent effect of TNF on EC monlayer permeability.

Significant increases in EC permeability were observed only with a 90-minute luminal (lum) versus abluminal (abl) exposure to 0.1 and 10 μg/mL TNF as described. Under identical conditions, vascular endothelial growth factor caused a significant increase in permeability with abluminal exposure, demonstrating a true specificity for the luminal TNF response.