vascular permeability increases during ventilated ischemia, before
reperfusion, in isolated ferret lungs. The mechanism of this injury is
not well understood, but it is likely to differ from other organs, as
pulmonary ischemia is not necessarily synonymous with hypoxia if
ventilation is maintained when blood flow is impaired.
Preliminary evidence from our laboratory demonstrates that
vascular endothelial growth factor (VEGF), a potent mediator of
increased vascular permeability, is upregulated during pulmonary
ischemia. Interestingly, this VEGF induction is not oxygen dependent
and occurs to the same degree in lungs ventilated with oxygen or
nitrogen during 180 min of ischemia.