Increased vascular permeability and angiogenesis at the site of blastocyst apposition in the
uterus are two hallmarks of the implantation process. The present investigation shows that
although the proangiogenic vascular endothelial growth factor (VEGF) and its receptor, Flk-
1, are primarily important for uterine vascular permeability and angiogenesis prior to and
during the attachment phase of the implantation process, VEGF in complementation with the
angiopoietins and their receptor, Tie-2, directs angiogenesis during decidualization …