Normal pregnancy is associated with dramatic increases in utero- and feto- placental blood flows which are directly correlated with fetal growth as well as neonatal birth weights and survivability. These increases in placental blood flows during late gestation result from both vasodilation and neovascularization. During the third trimester of ovine pregnancy, we and others reported expression of the potent angiogenic factors basic Fibroblast Growth Factor (bFGF) and Vascular Endothelial Growth Factor(VEGF) in ovine placental tissues. We also noted that the maternal and fetal compartments are associated with very pronounced productions of angiotensin II (ANG II); e.g. in sheep, fetal ANG II production is approximately 10-fold greater than maternal production. Overall hypothesis; Expression of the placental angiogenic factors, bFGF and VEGF, is modulated by ANG II via its AT-1 and/or AT-2 receptor subtypes and that these two growth factors modulate placental vascular growth to control blood flow. We will address this by using explant cultures of ovine placentomes and ovine fetoplacental arterial endothelial cell lines from the third trimester of ovine pregnancy. We propose to determine in the fetal vs maternal component of the placentome four specific aims; 1) if bFGF and VEGF expression and angiogenesis are increased during the third trimester; 2) if ANG II receptors AT-1 and/or AT-2 subtype binding/expression increase at this time; 3) if exogenous ANG II increases the expression of bFGF and VEGF, whether this is mediated through the AT-1 and/or the AT-2 receptor, and whether this is reflected in increases in angiogenic activity; and 4) if ANG II, via AT-1 and/or AT-2 receptors, directly affect the angiogenic and growth factor changes in placental artery endothelial cell lines. Expression of bFGF and VEGF will be evaluated functionally using techniques of immunoneutralization of explant- conditioned media and determining its effects on endothelial cell line proliferation and migration (two functional bioassays), as well as Western blots, Northern blots, immunocytochemistry, and in situ hybridization. Data from these studies will provide the first framework for understanding the role of the renin angiotensin system's local control of and interactions between angiogenesis and blood flow to the uterine and placental vasculature, which are critical for normal fetal growth and development.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL057653-03
Application #
2771562
Study Section
Special Emphasis Panel (ZHL1-CSR-N (S1))
Project Start
1996-09-30
Project End
2000-08-31
Budget Start
1998-09-01
Budget End
1999-08-31
Support Year
3
Fiscal Year
1998
Total Cost
Indirect Cost
Name
University of Wisconsin Madison
Department
Obstetrics & Gynecology
Type
Schools of Medicine
DUNS #
161202122
City
Madison
State
WI
Country
United States
Zip Code
53715
Magness, Ronald R; Phernetton, Terrance M; Gibson, Tiffini C et al. (2005) Uterine blood flow responses to ICI 182 780 in ovariectomized oestradiol-17beta-treated, intact follicular and pregnant sheep. J Physiol 565:71-83
Li, Yun; Zheng, Jing; Bird, Ian M et al. (2005) Effects of pulsatile shear stress on signaling mechanisms controlling nitric oxide production, endothelial nitric oxide synthase phosphorylation, and expression in ovine fetoplacental artery endothelial cells. Endothelium 12:21-39
Zheng, Jing; Bird, Ian M; Chen, Dong-Bao et al. (2005) Angiotensin II regulation of ovine fetoplacental artery endothelial functions: interactions with nitric oxide. J Physiol 565:59-69
Zheng, Jing; Wen, YunXia; Chen, Dong-Bao et al. (2005) Angiotensin II elevates nitric oxide synthase 3 expression and nitric oxide production via a mitogen-activated protein kinase cascade in ovine fetoplacental artery endothelial cells. Biol Reprod 72:1421-8
Byers, Michael J; Zangl, Amy; Phernetton, Terrance M et al. (2005) Endothelial vasodilator production by ovine uterine and systemic arteries: ovarian steroid and pregnancy control of ERalpha and ERbeta levels. J Physiol 565:85-99
Vonnahme, Kimberly A; Wilson, Matthew E; Li, Yun et al. (2005) Circulating levels of nitric oxide and vascular endothelial growth factor throughout ovine pregnancy. J Physiol 565:101-9
Li, Yun; Zheng, Jing; Bird, Ian M et al. (2004) Mechanisms of shear stress-induced endothelial nitric-oxide synthase phosphorylation and expression in ovine fetoplacental artery endothelial cells. Biol Reprod 70:785-96
Gibson, Tiffini C; Phernetton, Terrance M; Wiltbank, Milo C et al. (2004) Development and use of an ovarian synchronization model to study the effects of endogenous estrogen and nitric oxide on uterine blood flow during ovarian cycles in sheep. Biol Reprod 70:1886-94
Chen, Dong-Bao; Bird, Ian M; Zheng, Jing et al. (2004) Membrane estrogen receptor-dependent extracellular signal-regulated kinase pathway mediates acute activation of endothelial nitric oxide synthase by estrogen in uterine artery endothelial cells. Endocrinology 145:113-25
Chung, Jin-Young; Song, Yang; Wang, Yuping et al. (2004) Differential expression of vascular endothelial growth factor (VEGF), endocrine gland derived-VEGF, and VEGF receptors in human placentas from normal and preeclamptic pregnancies. J Clin Endocrinol Metab 89:2484-90

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