Angiogenic factors, such as VEGF family members
(VEGF, PIGF), angiopoietins and their receptors, are
thought to be significant for the regulation of placental
growth and vascular development.62 Angiopoietin 1
binds to Tie receptors, whereas angiopoietin 2 acts
as an antagonistic ligand.63 Impaired expression of
demonstrated decreased VEGF levels in the umbilical
cord from pregnancies complicated by hypertension as
compared to normal pregnancies.66 The angiopoietin
1/angiopoietin 2 ratio was found significantly lower in
women who developed preeclampsia than in normal
pregnant women.