Suppression of extravillous trophoblast vascular endothelial growth factor expression and uterine spiral artery invasion by estrogen during early baboon pregnancy

Prematurely elevating estradiol in early baboon pregnancy suppresses uterine artery remodeling and expression of extravillous placental vascular endothelial growth factor and α1β1 and α5β1 integrins

We previously showed that advancing the increase in estradiol levels from the second to the first third of baboon pregnancy suppressed placental extravillous trophoblast (EVT) invasion and remodeling of the uterine spiral arteries. Cell culture studies show that vascular endothelial cell growth factor (VEGF) plays a central role in regulating EVT migration and remodeling of the uterine spiral arteries by increasing the expression/action of certain integrins that control extracellular matrix remodeling. To test the hypothesis that the estradiol-induced reduction in vessel remodeling in baboons is associated with an alteration in VEGF and integrin expression, extravillous placental VEGF and integrin expression was determined on d 60 of gestation (term is 184 d) in baboons in which uterine artery transformation was suppressed by maternal estradiol administration on d 25-59. EVT uterine spiral artery invasion was 5-fold lower (P < 0.01), and VEGF protein expression, quantified by in situ proximity ligation assay, was 50% lower (P < 0.05) in the placenta anchoring villi of estradiol-treated than in untreated baboons. α1β1 and α5β1 mRNA levels in cells isolated by laser capture microdissection from the anchoring villi and cytotrophoblastic shell of estradiol-treated baboons were over 2-fold (P < 0.01) and 40% (P < 0.05) lower, respectively, than in untreated animals. In contrast, placental extravillous αvβ3 mRNA expression was unaltered by estradiol treatment. In summary, extravillous placental expression of VEGF and α1β1 and α5β1 integrins was decreased in a cell- and integrin-specific manner in baboons in which EVT invasion and remodeling of the uterine spiral arteries were suppressed by prematurely elevating estradiol levels in early pregnancy. We propose that estrogen normally controls the extent to which the uterine arteries are transformed by placental EVT in primate pregnancy by regulating expression of VEGF and particular integrin extracellular remodeling molecules that mediate this process.

Peak serum estradiol level during controlled ovarian hyperstimulation is associated with increased risk of small for gestational age and preeclampsia in singleton pregnancies after in vitro fertilization

OBJECTIVE

To assess the impact of elevated peak serum E(2) levels (EPE(2); defined as levels >90th percentile) on the day of hCG administration during controlled ovarian hyperstimulation (COH) for IVF on the likelihood for small for gestational age (SGA), preeclampsia (PreE), and preterm delivery (PTD) in singleton pregnancies.

DESIGN

Retrospective cohort study.

SETTING

Tertiary-care academic medical center.

PATIENT(S)

Singleton live-birth pregnancies conceived after fresh IVF-ET.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The delivery rate of SGA infants and the development of PreE and PTD in patients with and without EPE(2).

RESULT(S)

Patients with EPE(2) during COH were more likely to deliver SGA infants (7 [26.9%] vs. 10 [3.8%]; odds ratio [OR], 95% confidence interval [CI] {9.40, 3.22-27.46}) and develop PreE (5 [18.5%] vs. 12 [4.5%]; adjusted OR, 95% CI {4.79, 1.55-14.84}). No association was found between EPE(2) and the likelihood for delivery before 37 weeks, 35 weeks, or 32 weeks of gestation. Receiver operating characteristic analysis revealed that EPE(2) level predicted adverse obstetrical outcome (SGA + PreE) with 38.5% and 91.7% sensitivity and specificity, respectively. Using a serum peak E(2) cutoff value of 3,450 pg/mL (>90th percentile level), the positive predictive value was 37%, while the negative predictive value was 92%.

CONCLUSION(S)

EPE(2) level (>3,450 pg/mL) on the day of hCG administration during COH is associated with greater odds of developing PreE and delivery of an SGA infant in singleton pregnancies resulting from IVF cycles.

Effects of phytoestrogen extracts isolated from flax on hormone production of trophoblast tumour cells Jeg 3 and BeWo

AIM AND SETTING: To test the effects of crude extracts from flax (Linum usitatissimum) on progesterone and estradiol and ERα and β/PR production in choriocarcinoma cell lines Jeg 3 and BeWo. Tumor trophoblast cells (Jeg 3 and BeWo) were incubated in the presence of different concentrations of the flax crude extracts. Estradiol and progesterone production was measured. Estrogen receptor α and β as well as progesterone receptor expressions were also assessed.

RESULTS

In Jeg 3 cells, progesterone production was downregulated by flax root and leaves extract, while in BeWo cells only flax root extract did manage to downregulate progesterone production. ERβ expression was significantly downregulated by flax root and flax leaves extract in both cell lines; on the contrary, ERα expression was increased by flax leaves extract in BeWo cells. PR expression was downregulated by flax leaves extract in Jeg 3 and by flax root extract in BeWo cells.

CONCLUSION

Flax extracts derived from leaves and especially from roots can modify progesterone and possibly estradiol production, while at the same time they seem to alter ERβ expression. Further studies on animal models and adequately designed retrospective epidemiological studies are imperative to clarify this role upon progesterone.

Suppression of trophoblast uterine spiral artery remodeling by estrogen during baboon pregnancy: impact on uterine and fetal blood flow dynamics

The present study was conducted to determine the impact of suppressing trophoblast remodeling of the uterine spiral arteries by prematurely elevating estrogen levels in the first trimester of baboon pregnancy on uterine and umbilical blood flow dynamics. Uteroplacental blood flow was assessed by Doppler ultrasonography after acute administration of saline (basal state) and serotonin on days 60, 100, and 160 of gestation (term: 184 days) to baboons in which uterine spiral artery remodeling had been suppressed by the administration of estradiol on days 25-59 of gestation. Maternal blood pressure in the basal state was increased (P < 0.01), and uterine artery diastolic notching and the umbilical artery pulsatility index and systolic-to-diastolic ratio, reflecting downstream flow impedance, were increased (P < 0.01) after serotonin administration on day 160, but not earlier, in baboons treated with estradiol in early gestation. These changes in uteroplacental flow dynamics in serotonin-infused, estradiol-treated animals were accompanied by a decrease (P < 0.05) in uterine and umbilical artery volume flow and fetal bradycardia. The results of this study show that suppression of uterine artery remodeling by advancing the rise in estrogen from the second trimester to the first trimester disrupted uteroplacental blood flow dynamics and fetal homeostasis after vasochallenge late in primate pregnancy.

Vessel remodelling, pregnancy hormones and extravillous trophoblast function

During early human pregnancy, extravillous trophoblast (EVT) cells from the placenta invade the uterine decidual spiral arterioles and mediate the remodelling of these vessels such that a low pressure, high blood flow can be supplied to the placenta. This is essential to facilitate normal growth and development of the foetus. Defects in remodelling can manifest as the serious pregnancy complication pre-eclampsia. During the period of vessel remodelling three key pregnancy-associated hormones, human chorionic gonadotrophin (hCG), progesterone (P(4)) and oestradiol (E(2)), are found in high concentrations at the maternal-foetal interface. Potentially these hormones may control EVT movement and thus act as regulators of vessel remodelling. This review will discuss what is known about how these hormones affect EVT proliferation, migration and invasion during vascular remodelling and the potential relationship between hCG, P(4), E(2) and the development of pre-eclampsia.

The effects of human chorionic gonadotrophin, progesterone and oestradiol on trophoblast function

Remodelling of the uterine vasculature during the first trimester of human pregnancy requires invasion of trophoblast from the placenta into decidual spiral arterioles. The pregnancy-associated hormones human chorionic gonadotropin (hCG), progesterone (P(4)) and oestradiol (E(2)) are present at high concentrations at the maternal-fetal interface during the remodelling period and thus may contribute to the regulation of trophoblast movement. This study examined the effects of these hormones on trophoblast functions. HTR8/SVneo cells were treated with hCG (5-100mIU/mL), P(4) (20nM-20μM) or E(2) (0.07-734nM). hCG significantly stimulated migration and MMP-9 activity but did not affect cell numbers. P(4) significantly inhibited migration, MMP-2 and -9 activity and reduced cell numbers. E(2) had no effect on migration, MMP activity or cell numbers. We conclude that hCG and P(4), but not E(2), play direct roles in controlling trophoblast invasion, acting as positive and negative stimuli respectively to regulate trophoblast movement during vascular remodelling in early pregnancy.

Stimulation of serotonergic 5-HT2A receptor signaling increases placental aromatase (CYP19) activity and expression in BeWo and JEG-3 human choriocarcinoma cells

It is known that serotonin can influence the production and function of sex hormones, such as estrogens. Estrogens are critical for maintenance of pregnancy and regulate placental and fetal development. The key enzyme controlling estrogens synthesis during pregnancy is placental aromatase (CYP19). To better understand the regulation of placental aromatase, this study determined whether serotonin is involved in the regulation of this enzyme. BeWo and JEG-3 choriocarcinoma cells were used as models of the human placental trophoblast to evaluate the effects of serotonin and selective 5-HT(2A) receptor agonists on CYP19 activity and expression. Serotonin and selective 5-HT(2A) receptor agonists as well as PKC activation increased aromatase activity and expression in BeWo and JEG-3 cells. Dexamethasone, which regulates aromatase expression via JAK/STAT activation in certain tissues, had no effect. Increased CYP19 gene transcription by 5-HT(2A) receptor and PKC stimulation was mediated by activation of the placental I.1 aromatase promoter. This study shows that the serotonergic system modulates placental aromatase expression, which would result in altered estrogens biosynthesis in trophoblast cells. Future detailed studies of serotonin-estrogen interactions in placenta are crucial for an improved understanding of the endo-, para- and autocrine role of serotonin during pregnancy and fetal development.

Estrogen regulation of placental angiogenesis and fetal ovarian development during primate pregnancy

During human and nonhuman primate pregnancy, an extensive blood vessel network is established within the villous placenta to support fetal growth and follicles develop within the fetal ovary to provide a pool of oocytes for reproductive function in adulthood. These two important developmental events occur in association with a progressive increase in placental estrogen production and levels. This review will describe the developmental processes required for placental vascularization and fetal follicular maturation and recent studies which show that estrogen has an important role in regulating these events.