Vascular endothelial growth factor activation of intramembranous absorption: a critical pathway for amniotic fluid volume regulation.
OBJECTIVE
The purpose of this review is to propose a critical role for vascular endothelial growth factor (VEGF) in mediating the transfer of amniotic fluid from the amniotic compartment through the fetal membranes and fetal surface of the placenta into fetal blood.


METHODS
Experimental findings in humans and animal models on the action of VEGF in mediating fluid transfer are reviewed and interpreted in order to postulate a proposed mechanism for VEGF regulation of amniotic fluid absorption through the fetal membranes and placenta.


RESULTS
Recent scientific advances suggest that up-regulation of VEGF gene expression in the amnion and chorion is associated with increased transfer of amniotic fluid into fetal blood. The possible mechanisms of action for VEGF appear to involve regulation of intramembranous blood vessel proliferation and membrane transport via passive permeation as well as nonpassive transcytotic vesicular movement of fluid.


CONCLUSIONS
Currently evolving concepts suggest that amniotic fluid volume is regulated through modulation of the rate of intramembranous absorption of amniotic fluid by both passive and nonpassive mechanisms. The permeability factor VEGF appears to be a critical regulator of amniotic fluid transport in the fetal membranes.
Cheung
Cecilia Y
CY
Division of Perinatal Medicine, Department of Reproductive Medicine, University of California at San Diego, La Jolla, California 92093-0802, USA. cucheung@ucsd.edu
D000042:Absorption / Q000187:drug effects; D000650:Amnion / Q000378:metabolism; D000653:Amniotic Fluid / Q000378:metabolism*; D000818:Animals; D002823:Chorion / Q000378:metabolism; D005321:Extraembryonic Membranes / Q000098:blood supply / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D018919:Neovascularization, Physiologic; D010920:Placenta / Q000098:blood supply / Q000378:metabolism*; D011247:Pregnancy; D040262:Receptors, Vascular Endothelial Growth Factor; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000494:pharmacology*; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000235:genetics
D042461:Vascular Endothelial Growth Factor A; D040262:Receptors, Vascular Endothelial Growth Factor; D040301:Vascular Endothelial Growth Factor Receptor-2