Ds. Goldman-wohl et al., Tie-2 and angiopoietin-2 expression at the fetal-maternal interface: a receptor ligand model for vascular remodelling, MOL HUM REP, 6(1), 2000, pp. 81-87
The blood vessels at the fetal-maternal interface widen dramatically during
pregnancy in order to increase blood flow to nourish the developing fetus.
This vessel remodelling destroys normal vessel integrity and encompasses t
he dissolution of vessel muscle and elastic tissue. It also includes the di
splacement of endothelial cells by fetal trophoblasts that invade the mater
nal arteries of the uterus. Interaction between the endothelial cell recept
or, Tie-a, and its recently discovered antagonist ligand, angiopoietin-2 (A
ng-2), has been implicated in the loosening of vessel structure. Using Nort
hern blot hybridization and RNA in-situ hybridization analysis the expressi
on pattern of Tie-2, and Ang-2 in the placenta throughout pregnancy, was in
vestigated. We found Ang-2 expressed in the syncytiotrophoblast during the
first trimester. In addition to the expected expression of the Tie-2 recept
or in both fetal and maternal endothelial cells, we observed Tie-2 expressi
on in endovascular invasive trophoblasts. These cells of epithelial origin
invade the uterine spiral arteries and acquire endothelial cell properties.
The temporal- and lineage-specific pattern of expression of Tie-2 and Ang-
2 suggests that this receptor-ligand pair functions during the critical pha
se of development of the fetal vasculature and reworking of the maternal ve
ssels during normal placentation.