Short term effects of gamma radiation on endothelial barrier function: Uncoupling of PECAM-1

► Acute disruption of endothelial barrier function at 3 h post gamma irradiation. ► Transient dip in trans-endothelial resistance loss of PECAM-1 and cell detachment. ► Occurs in human vein and brain micro-capillary models at radiotherapy dose of 2 Gy. ► Although barriers are repaired there is longer-term reduction in permeability. ► Has the potential to be clinically relevant to the vasculopathies of radiotherapy.