Isolated Placental Vessel Response to Vascular Endothelial Growth Factor and Placenta Growth Factor in Normal and Growth-Restricted Pregnancy

Abstract

Vascular endothelial growth factor (VEGF) and placenta growth factor (PlGF) cause vasodilation. We examined the vasomotor response of isolated placental vessels to VEGF and PlGF in normal (group I) and intrauterine growth retardation (IUGR)-complicated pregnancy (group II). Rings of vessels were prepared in vitro and mounted on the vessel myograph plunged in tissue bath. The magnitude of dilation to increased doses of VEGF and PlGF has been studied. VEGF is a more potent vasodilator than PlGF. Both, VEGF- and PlGF-induced vasorelaxation was diminished in the IUGR (group II) nearly by half, compared to control (group I). Relative placental nitric oxide deficiency, or decreased sensitivity to VEGF and PlGF may contribute to the development of high impedance fetoplacental circulation.

Endothelial-Derived Hyperpolarization Factor (EDHF) Contributes to PlGF-Induced Dilation of Mesenteric Resistance Arteries from Pregnant Rats

“…The potent vasodilatory effect observed in intact MRA was lost in denuded arterial segments, demonstrating that the endothelium was both necessary and sufficient for its action. Although other studies have documented PlGF vasodilation in other types of vessels [7,8,9], this is the first proof of its endothelial dependence in resistance vessels, and during pregnancy.…”

“…The vasodilatory actions of PlGF have been reported in a number of vessel types, including human placental and internal mammary arteries [7,8], piglet pulmonary vessels [9], rat aorta and renal arterioles [6,10]. Earlier, we found PlGF to be a potent vasodilator of human and rat resistance arteries from several circulations (splanchic, uterine, subcutaneous [11]).…”

Angiogenesis in implantation

“…IFN-γ inhibits growth of endothelial cells and capillary formation in a dose dependent manner [41], and lymphocytes are reported to be the major source of IFN-γ within the endometrium of pigs [42]. The anti-angiogenic effects of IL-12 are currently being investigated in various tumor cell lines due to the in vitro evidence that IL-12 inhibits VEGF production by mammary adenocarcinoma cells [37].…”

The feto-placental endothelium in pregnancy pathologies

“…This finding seems to be associated with reduced nitric oxide synthase (NOS) [30], eNOS phosphorylation and, ultimately, NO [31] in umbilical artery endothelium and human umbilical vein endothelial cells from FGR pregnancies. Moreover, VEGFA and placental growth factor induced vasorelaxation is diminished in umbilical vessels in FGR [32] further demonstrating impaired responsiveness of the vessels.…”