Placental Angiogenesis Research Articles

The characterization of fibrocyte-like cells: A novel fibroblastic cell of the placenta

The placenta is a highly vascularized organ thus angiogenesis is a key process in placental development. The contribution that different cells in the villous stroma play in placental angiogenesis is largely unknown. In this study we identified a novel stromal cell type in sections of term placenta which is morphologically fibroblastic and expressing the fibroblast marker TE-7 but also positive for the monocytic markers CD115 and CD14 and designated these cells as fibrocyte-like cells. Populations of fibrocyte-like cells from the placenta were isolated by two methods: culture of adherence-selected placental cells and, for higher purity, by CD45 fluorescence activated cell sorting (FACS).Fibrocyte-like cell conditioned medium increased endothelial tubule-like structure formation 2-fold versus control medium. Both pro-angiogenic growth factors vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (b-FGF) and the anti-angiogenic factor soluble-Flt were found in the conditioned medium. Neutralizing antibodies against VEGF and b-FGF reduced endothelial cell tubule-like structures to control levels. These data suggests that fibrocyte-like cells, a previously unidentified cell of the villous stroma, may play an important role in the regulation of placental angiogenesis.

Notch Signaling Pathway and Human Placenta

Notch signaling was evolutionarily conserved and critical for cell-fate determination, differentiation and many other biological processes. Growing evidences suggested that Notch signaling pathway played an important role in the mammalian placental development. All of the mammalian Notch family proteins had been identified in human placenta except Delta-like 3, which appeared to affect the axial skeletal system. However the molecular mechanisms that regulated the Notch signaling pathway remained largely unknown in human placenta. Therefore, additional research was needed to investigate expression pattern of Notch family members and the mechanisms for activation of Notch signaling pathway in human placenta, which might help elucidate the roles of Notch signaling pathway in human placentation. This review would focus on the roles of Notch receptors and ligands in the human placental trophoblasts function and placental angiogenesis. It might hopefully provide perspectives for future research about human placentation of pregnancy complicated by preeclampsia and other placenta associated diseases.

Vascular endothelial growth factor gene 1154 G/A, 2578 C/A, 460 C/T, 936 C/T polymorphisms and association with recurrent pregnancy losses

Vascular endothelial growth factor (VEGF) regulates endothelial cell proliferation, migration and differentiation. VEGF plays a critical role in angiogenesis during placenta formation. We investigated whether VEGF gene polymorphisms are associated with recurrent pregnancy loss. Thirty-eight women with recurrent pregnancy loss and 30 control women with live-born children were recruited from 2010 to 2011 in the region of Bursa, Turkey. VEGF gene polymorphisms were assessed with PCR-RFLP analysis of DNA samples obtained from leukocytes. DNA fragments were investigated by using appropriate primers. SNP scanning was performed using MnII, BgIII, BshI2361, Hsp92II restriction enzymes for 1154 G/A, 2578 C/A, 460 C/T, and 936 C/T polymorphisms, respectively. The frequencies of 2578 C/A, 460 C/T, 936 C/T polymorphisms were not significantly different between the controls and women with recurrent pregnancy loss. However, the prevalence of the 1154 G/A polymorphism A/A genotype was significantly higher in the recurrent pregnancy loss group (23.7 vs 3.4%). One of the four common polymorphisms of the VEGF gene was found to be more frequent in women with recurrent pregnancy loss. It is possible that disruption of VEGF function and placental angiogenesis can contribute to pregnancy loss in women with recurrent pregnancy loss.

Cytokines in Placental Physiology and Disease

Cytokines in Placental Physiology and Disease

Exploring the potential of low doses carbon monoxide as therapy in pregnancy complications

Heme Oxygenase-1 (HO-1) has been shown to play a pivotal role in pregnancy outcome and its ablation leads to abnormal placentation, intrauterine fetal growth restriction (IUGR) and subsequent intrauterine fetal death. Carbon monoxide (CO) has been found to mimic the protective effects of HO-1 activity, rescuing HO-1-deficient fetuses. This gasotransmitter arises in biological systems during the oxidative catabolism of heme by HO. Here, we explored the potential of CO in preventing IUGR and established the optimal doses and therapeutic time window in a clinically relevant mouse model. We additionally investigated the pathways activated upon CO application in vivo. We established 50 ppm as the best lowest dose of CO necessary to prevent growth restriction being the optimal time frame during days 3 to 8 of mouse pregnancy. CO lead to higher fetal and placental weights and avoided fetal death without showing any pathologic effects. CO breathing further suppressed inflammatory responses, diminished placenta apoptosis and complement deposition and regulated placental angiogenesis. Our results confirm the protective role of the HO-1/CO axis and point this gas as an emerging therapeutic possibility which is worth to further explore.

A longitudinal study of three-dimensional ultrasonographic assessment of the placenta in uncomplicated pregnancies

Copyright © 2012. Korean Society of Obstetrics and Gynecology Placental vascularization is important for normal pregnancy. The circulatory function of the placenta appears at an early stage of embryo-placental development and is strongly related to fetal growth, placental volume, and uterine blood flow. Therefore, adequate placental angiogenesis is critical for the establishment of normal placental vascularization with subsequent normal development of the fetus [1,2]. Recent advances in technology allow the combination of 3-dimensional (3-D) ultrasound with power Doppler, making it possible to quantify Doppler signals in a volume obtained by 3D scanning and allowing investigation of the placental circulation. Each calculation of the vascularization index (VI), flow index (FI), and vascularization-flow index (VFI) is defined through technological quantification, and these indices are thought to reflect the number of vessels within the volume of interest, the intensity of flow at the time of the 3-D sweep, and both blood flow and vascularization [3]. ORIGINAL ARTICLE Korean J Obstet Gynecol 2012;55(7):454-460 http://dx.doi.org/10.5468/KJOG.2012.55.7.454 pISSN 2233-5188 · eISSN 2233-5196

195: Differential expression of tunica internal endothelial cell kinase in the center and periphery of normal and growth restricted placentas

Aberrant placental angiogenesis has a role in fetal growth restriction (FGR). Angiogenic factors have been found to differ between the center and periphery of normal placentas. Tunica Internal Endothelial Cell Kinase (Tie2) is an endothelial cell-specific receptor tyrosine kinase, whose activation is positively and negatively modulated by angiopoietin family. Angiopoietin-mediated modulation of Tie2 activation contributes to normal blood vessel development, maturation, maintenance, remodeling and stability.

The expression and localization of the human placental prorenin/renin-angiotensin system throughout pregnancy: Roles in trophoblast invasion and angiogenesis?

The renin-angiotensin system (RAS) is thought to regulate placentation, however, the expression and localization of RAS pathways in early gestation human placenta is not known. Here we describe the expression of prorenin (REN), (pro)renin receptor (ATP6AP2), angiotensinogen (AGT), angiotensin-converting enzyme 1 and 2 (ACE; ACE2), angiotensin II type 1 and 2 receptors (AGTR1; AGTR2) and angiotensin 1–7 receptor (MAS1), as well as the angiogenic factor, vascular endothelial growth factor (VEGF), and transforming growth factor-β1 (TGF-β1), in early gestation (6–16 weeks) and term (>37 weeks) human placentae. We also describe the location of all of the key RAS proteins in the early gestation placentae. The highest levels of REN, ATP6AP2, AGT, AGTR1 and ACE2 mRNAs were found in early gestation, whereas ACE1 mRNA was highest at term. AGTR2 and MAS1 mRNA expression were low to undetectable in all samples. REN, ATP6AP2 and AGTR1 mRNA levels were correlated with VEGF expression, but not with TGF-β1 mRNA. In early gestation placentae, prorenin, (pro)renin receptor and the angiotensin II type 1 receptor (AT1R) were localized to extravillous trophoblast cells, suggesting they play a key role in trophoblast migration. ACE2 in syncytiotrophoblasts could regulate release of Ang 1-7 into the maternal circulation contributing to the vasodilation of the maternal vasculature. ACE was only found in fetal vascular endothelium and may specifically target the growing fetal placental vessels. Because REN, ATP6AP2 and AGTR1 show strong correlations with expression of VEGF this pathway is likely to be important in placental angiogenesis.

Norrin immunolocalization and its possible functions in rat endometrium during the estrus cycle and early pregnancy

Mutations in Norrie Disease Pseudoglioma (NDP) gene cause serious sight loss, deafness and mental retardation in Norrie disease patients via the impairment of angiogenesis. Since norrin is a Wnt pathway ligand, it could function in several tissues other than eye and nervous systems. Therefore, the aim of the present study was to determine the possible function of norrin in angiogenesis, cellular differentiation in stroma and in decidua and the survival of those cells using immunofluorescent labeling. While norrin had a uniform distribution in stroma and in blood vessels, it had a strong expression in luminal and glandular epithelia during the estrus cycle. Norrin had strong immunolocalization in the antimesometrial decidual reaction zone on day 7 of gestation, whereas it had a decreased expression in the mesometrial uterine luminal epithelium along with an increased localization in blood vessels and decidual cells of the same region on day 8 of gestation. As from day 9 of gestation, norrin demonstrated rather strong expression in the decidual cells and blood vessels of the mesometrial region in which the chorioallantoic placenta was going to develop. In all periods studied, norrin had rather weak expression in the primary decidual zone surrounding the embryo. Findings of the present study suggested that norrin might regulate the decidual reaction and the placental angiogenesis along with the survival and the differentiation of luminal and glandular epithelial and decidual cells in rats. In addition, it could play indirect important roles in the control of trophoblastic invasion and the programmed cell death.

Role of nitric oxide in placental vascular development and function

Nitric oxide (NO) is one of the most pleiotropic signaling molecules at systemic and cellular levels, participating in vascular tone regulation, cellular respiration, proliferation, apoptosis and gene expression. Indeed NO actively participates in trophoblast invasion, placental development and represents the main vasodilator in this tissue. Despite the large number of studies addressing the role of NO in the placenta, its participation in placental vascular development and the effect of altered levels of NO on placental function remains to be clarified. This review draws a time-line of the participation of NO throughout placental vascular development, from the differentiation of vascular precursors to the consolidation of vascular function are considered. The influence of NO on cell types involved in the origin of the placental vasculature and the expression and function of the nitric oxide synthases (NOS) throughout pregnancy are described. The developmental processes involved in the placental vascular bed are considered, such as the participation of NO in placental vasculogenesis and angiogenesis through VEGF and Angiopoietin signaling molecules. The role of NO in vascular function once the placental vascular tree has developed, in normal pregnancy as well as in pregnancy-related diseases, is then discussed.

Compartmentalizing Proximal FGFR1 Signaling in Placental Artery Endothelial Cell Caveolae.

Fibroblast growth factor-2 (FGF2) signaling via FGF receptor 1 (FGFR1) is critical for fetal placental angiogenesis. We have recently shown that the flask-shaped plasma membrane microdomain caveolae function as a platform for compartmentalizing ERK1/2 and AKT pathways activated by FGF2 and VEGF in placental artery endothelial cells. However, whether the proximal FGFR1 signaling events are also compartmentalized in the caveolae has not been explored. Proximal FGFR1 signaling is unique in that it is mediated by direct binding to and phosphorylating an adaptor protein FGFR substrate 2 (FRS2); this results in Grb2-mediated ERK2/1 activation and Gab1-mediated PI3K/Akt signaling. The objective of this study was to determine if the proximal FGFR1 signaling events are compartmentalized in placental endothelial cell caveolae. In ovine fetoplacental artery endothelial cells (oFPAEC), FGF2 treatment induced FRS2 phosphorylation on Tyr196 in a time- and dose-dependent fashion. Co-immunoprecipitation (Co-IP) experiments demonstrated that FGF2 rapidly and transiently increased the levels of FGFR1 bound FRS2 and the formation of a ternary complex FRS2-Gab1-Grb2 in oFPAEC. Co-IP and double fluorescence labeling experiments showed that FGFR1 and FRS2 was associated with the major caveolar structural protein caveolin-1 and co-purified with caveolin-1 in caveolae membranes. In oFPAEC treated with the cholesterol depletant methyl-β-cyclodextrin (MβCD) to disrupt caveolae, FGF2-induced FRS2 phosphorylation was inhibited and FGF2-induced formation of FRS2-Gab1-Grb2 complex was greatly attenuated. Subsequently, FGF2 was no longer able to activate the ERK/2 and Akt signaling pathways. Thus, integral caveolae compartmentalizes the proximal FGFR1 signaling via FRS2 and the formation of a ternary complex FRS2-Gab1-Grb2 (Supported by RO1 HL74947). (poster)

Preeclampsia, a disease of the maternal endothelium: the role of antiangiogenic factors and implications for later cardiovascular disease.

Preeclampsia is a clinical syndrome defined as the new onset of hypertension and proteinuria during the second half of pregnancy.1 It afflicts 3% to 5% of pregnancies and is a leading cause of maternal mortality, especially in developing countries.2,3 Because the only known remedy is delivery of the placenta, in developed countries preeclampsia is an important cause of premature delivery, usually medically indicated for the benefit of the mother. This results in infant morbidity and substantial healthcare expenditure.4 Despite the considerable morbidity and mortality, the cause of preeclampsia has remained enigmatic. Both hypertension and proteinuria implicate the endothelium as the target of the disease. The hypertension of preeclampsia is characterized by peripheral vasoconstriction and decreased arterial compliance.5,6 The proteinuria of preeclampsia is associated with a pathognomonic renal lesion known as glomerular endotheliosis, in which the endothelial cells of the glomerulus swell and endothelial fenestrations are lost.7,8 Podocyturia has been recently associated with preeclampsia during clinical disease9; however, whether this is the cause or effect of proteinuria is unknown. The glomerular filtration rate is decreased compared with normotensive pregnant women; in rare cases, acute renal failure may develop. Preeclampsia is a systemic vascular disorder that may also affect the liver and the brain in the mothers. When the liver is involved, women may present with abdominal pain, nausea, vomiting, and elevated liver enzymes. Pathological examination of the liver reveals periportal and sinusoidal fibrin deposition and, in more extreme cases, hemorrhage and necrosis.10 The severe preeclampsia variant HELLP syndrome (hemolysis, elevated liver enzymes, low platelets) occurs in ≈20% of women with severe preeclampsia,11 and is named not only for the liver involvement, but also for the disorder of the coagulation system that develops.12 Approximately 20% of …

A review of the evolution of viviparity in squamate reptiles: the past, present and future role of molecular biology and genomics

Squamate reptiles (lizards and snakes) offer a unique model system for testing hypotheses about the evolutionary transition from oviparity (egg-laying) to viviparity (live-bearing) in amniote vertebrates. The evolution of squamate viviparity has occurred remarkably frequently (>108 times) and has resulted in major changes in reproductive physiology. Such frequent changes in reproductive strategy pose two questions: (1) what are the molecular mechanisms responsible for the evolution of squamate viviparity? (2) Are these molecular mechanisms the same for separate origins of viviparity? Molecular approaches, such as RT-PCR, in situ hybridisation, Western blotting and immunofluorescence, have been invaluable for identifying genes and proteins that are involved in squamate placental development, materno-foetal immunotolerance, placental transport, placental angiogenesis, hormone synthesis and hormone receptor expression. However, the candidate-gene or -protein approach that has been used until now does not allow for de novo gene/protein discovery; results to date suggest that the reproductive physiologies of mammals and squamate reptiles are very similar, but this conclusion may simply be due to a limited capacity to study the subset of genes and proteins that are unique to reptiles. Progress has also been slowed by the lack of appropriate molecular and genomic resources for squamate reptiles. The advent of next-generation sequencing provides a relatively inexpensive way to conduct rapid high-throughput sequencing of genomes and transcriptomes. We discuss the potential use of next-generation sequencing technologies to analyse differences in gene expression between oviparous and viviparous squamates, provide important sequence information for reptiles, and generate testable hypotheses for the evolution of viviparity.

Effects of netrin-1 and netrin-1 knockdown on human umbilical vein endothelial cells and angiogenesis of rat placenta

Angiogenesis is an important process essential for the development of placenta. Netrin-1 was first discovered in nervous system and was later found to play roles in angiogenesis. In order to better understand the functional relevance of netrin-1 in placental angiogenesis, we investigated the effect of netrin-1 on human umbilical vein endothelial cells (HUVECs) and rat placenta by employing up-regulation and down-regulation strategies. HUVECs and rat placenta were treated with recombinant netrin-1, and netrin-1 expression in the cells and placenta was reduced by short hairpin RNA (shRNA) in vitro and in vivo. The inhibition efficiency was determined by real-time quantitative polymerase chain reaction (RT-PCR) and Western blotting. The expression of netrin-1 was immunohistochemically located. The results demonstrated that netrin-1 promoted viability, proliferation, migration and tube formation of HUVECs. A strong reduction in cell capability was observed in vitro after netrin-1 expression was inhibited with shRNA. Netrin-1 accelerated neovascularization of placenta in pregnant rats. Suppression of netrin-1 expression in placenta resulted in reduced vascular sprouting in vivo. These findings suggest that netrin-1 is essential for the proper functioning of HUVECs and angiogenesis of rat placenta, and it is involved in the development of placenta and fetus. The proangiogenic effect of netrin-1 might offer an alternative therapeutic approach for the treatment of vascular disease of placenta.

Complement activation: a critical mediator of adverse fetal outcomes in placental malaria?

Malaria infection is a significant risk factor for low birth weight outcomes in pregnancy. Despite efforts to define the molecular mechanisms that cause low birth weight as a result of intrauterine growth restriction, the roles of inflammation and mononuclear cells in the process are incompletely understood. Data from adverse pregnancy outcomes in humans and from murine models of pathological pregnancies suggest that C5a could be an important upstream regulator of placental angiogenesis, and excessive C5a could lead to functional placental insufficiency by impairing adequate vascularization of the placenta. Based on recent evidence, we hypothesize that complement factor C5a is a central initiator of poor birth outcomes associated with placental malaria by promoting mononuclear cell migration, activation and dysregulated angiogenesis.

Airway angiopoietin‐2 in ventilated very preterm infants: Association with prenatal factors and neonatal outcome

Pulmonary angiogenesis is a prerequisite for lung development. Angiopoietin-2 (Ang2) destabilizes endothelial cells through its endothelial receptor TIE-2, enabling vascular sprouting. Ang1 stabilizes new blood vessels. Soluble TIE-2 (sTIE-2) modulates these effects. We hypothesized that histological funisitis is associated with alterations of Ang2 in airways and of the systemic angiopoietin-TIE-2 homeostasis in very low birth weight (VLBW) infants, contributing to pulmonary morbidity and mortality. We measured Ang2 in tracheobronchial aspirate fluid (TAF) of 42 VLBW <30 weeks of gestation from day 1 through 15 and Ang1, Ang2, and sTIE-2 in umbilical cord serum of 28 infants by enzyme-linked immunosorbent assay. Histological examination distinguished three groups: funisitis, chorioamnionitis, and controls. Funisitis was associated with lower Ang2 values in TAF but not with changes of Ang1, Ang2, and sTIE-2 in umbilical cord serum. Infants who developed bronchopulmonary dysplasia (BPD) or died had a persistently decreased ratio of previously measured Ang1 to Ang2 in TAF on days 1-5 and increased cord serum concentrations of sTIE-2. Moderate BPD/death was associated with an increase of Ang2 in TAF on day 10 and decreased Ang1/Ang2 ratio from day 3-15. Small for gestational age (SGA) infants had increased Ang2 in TAF on day 1-7 and a lower Ang1/Ang2 ratio on days 5-7. The predominance of Ang2 in airway fluid of infants with BPD/death and SGA infants suggests a link between disrupted placental and fetal pulmonary angiogenesis. Histological funisitis with reduced Ang2 in TAF was of minor relevance for outcome in our cohort.

A Critical Role of Interleukin-10 in Modulating Hypoxia-Induced Preeclampsia-Like Disease in Mice

Hypoxia has been implicated in the pathogenesis of preeclampsia, a hypertensive disorder of pregnancy. However, in vivo evidence and mechanistic understanding remain elusive. Preeclampsia is associated with impaired placental angiogenesis. We have recently shown that interleukin (IL)-10 can support trophoblast-driven endovascular crosstalk. Accordingly, we hypothesize that pathological levels of oxygen coupled with IL-10 deficiency induce severe preeclampsia-like features coupled with elevated production of antiangiogenic factors, apoptotic pathways, and placental injury. Exposure of pregnant wild-type and IL-10(-/-) mice to 9.5% oxygen resulted in graded placental injury and systemic symptoms of renal pathology, proteinuria (wild-type 645.15 ± 115.73 versus 198.09 ± 93.45; IL-10(-/-) 819.31 ± 127.85 versus 221.45 ± 82.73 μg/mg/24 hours) and hypertension (wild-type 118.37 ± 14.45 versus 78.67 ± 14.07; IL-10(-/-) 136.03 ± 22.59 versus 83.97 ± 18.25 mm Hg). Recombinant IL-10 reversed hypoxia-induced features in pregnant IL-10(-/-) mice confirming the protective role of IL-10 in preeclampsia. Hypoxic exposure caused marked elevation of soluble fms-like tyrosine kinase 1 (110.8 ± 20.1 versus 44.7 ± 11.9 ng/mL) in IL-10(-/-) mice compared with their wild-type counterparts (81.6 ± 13.1 versus 41.2 ± 8.9 ng/mL), whereas soluble endoglin was induced to similar levels in both strains (approximately 380 ± 50 versus 180 ± 31 ng/mL). Hypoxia-induced elevation of p53 was associated with marked induction of proapoptotic protein Bax, downregulation of Bcl-2, and trophoblast-specific apoptosis in utero-placental tissue. Collectively, we conclude that severe preeclampsia pathology could be triggered under certain threshold oxygen levels coupled with intrinsic IL-10 deficiency, which lead to excessive activation of antiangiogenic and apoptotic pathways.

204: Regional variation in placental expression of angiopoietin-1 and angiopoietin-2 in normal pregnancies

Fetal growth and development are dependent on the adequacy of placental angiogenesis. Angiopoietin 1 (Ang-1) and angiopoietin 2 (Ang-2) are known to be involved in this process. However, there is a dearth of information on the regional variations in Ang-1 and Ang-2 activity in human placenta. Such information would elucidate molecular regulation of placental angiogenesis in health and disease. The aim of this study was to test the hypothesis that there are regional variations in Ang-1 and Ang-2 expression, and the Ang-1/Ang-2 ratio in human placenta.

Recombinant Vascular Endothelial Growth Factor 121 Attenuates Autoantibody-Induced Features of Pre-eclampsia in Pregnant Mice

Pre-eclampsia (PE) is a serious hypertensive disorder of pregnancy characterized by excessive production of a soluble form of the vascular endothelial growth factor (VEGF) receptor-1, termed soluble fms-like tyrosine kinase-1 (sFlt-1). This placental-derived factor is believed to be a key contributor to the clinical features of PE. Women with PE are also characterized by the presence of autoantibodies, termed angiotensin type 1 receptor activating autoantibody (AT(1)-AA), that activate the major angiotensin receptor, AT(1). These autoantibodies cause clinical features of PE and elevated sFlt-1 when injected into pregnant mice. The research reported here used this autoantibody-injection model of PE to assess the therapeutic potential of recombinant VEGF(121), a relatively stable form of the natural ligand. Immunoglobulin G (IgG) from women with PE was injected into pregnant mice with or without continuous infusion of recombinant VEGF(121). Injected mice were monitored for symptoms of PE. As a result of infusion of recombinant VEGF(121) autoantibody-induced hypertension (systolic blood pressure) was reduced from 159 ± 5 to 124 ± 5 mm Hg, proteinuria from 111 ± 16 to 40 ± 5 mg protein/mg creatinine and blood urea nitrogen levels from 31 ± 1 mg/dl to 18 ± 2 mg/dl, P < 0.05. Histological analysis revealed that autoantibody-induced glomerular damage including the narrowing of Bowman's space and occlusion of capillary loop spaces was largely prevented by VEGF(121) infusion. Finally, impaired placental angiogenesis resulting from AT(1)-AA injection was significantly improved by VEGF(121) infusion. The infusion of recombinant VEGF(121) significantly attenuated autoantibody-induced features of PE.

Angiotensin II and angiotensin-(1-7) decrease sFlt1 release in normal but not preeclamptic chorionic villi: an in vitro study

BackgroundDuring preeclampsia, placental angiogenesis is impaired. Factors released from the placenta including vascular endothelial growth factor (VEGF), placental growth factor (PLGF), soluble VEGF receptor 1 (sFlt1), and soluble endoglin (sEng) are regulatory molecules of placental development and function. While the renin angiotensin system has been shown to regulate angiogenic factors in other research fields, these mechanisms have not been extensively studied during pregnancy.MethodsWe evaluated the effects of angiotensin II (Ang II) and angiotensin-(1-7) [Ang-(1-7)] on the release of VEGF, PLGF, sFlt1, and sEng from placental chorionic villi (CV). CV were collected from nulliparous third-trimester normotensive and preeclamptic subjects. CV were incubated for 0, 2, 4, and 16 hours with or without Ang II (1 nM and 1 microM) or Ang-(1-7) (1 nM and 1 microM). The release of VEGF, PLGF, sFlt1, sEng, lactate dehydrogenase (LDH), and human placenta lactogen (HPL) was measured by ELISA.ResultsThe release of sFlt1, PLGF, sEng from normal and preeclamptic CV increased over time. Release of sFlt1 and sEng was significantly higher from preeclamptic CV. VEGF was below the detectable level of the assay in normal and preeclamptic CV. After 2 hours, sFlt1 release from normal CV was significantly inhibited with Ang II (1 nM and 1 microM) and Ang-(1-7) (1 nM and 1 microM). There was a time-dependent increase in HPL indicating that the CV were functioning normally.ConclusionsOur study demonstrates a critical inhibitory role of angiotensin peptides on sFlt1 in normal pregnancy. Loss of this regulation in preeclampsia may allow sFlt1 to increase resulting in anti-angiogenesis and end organ damage in the mother.