Connecting G protein-coupled estrogen receptor biomolecular mechanisms with the pathophysiology of preeclampsia: a review

BACKGROUND

Throughout the course of pregnancy, small maternal spiral arteries that are in contact with fetal tissue undergo structural remodeling, lose smooth muscle cells, and become less responsive to vasoconstrictors. Additionally, placental extravillous trophoblasts invade the maternal decidua to establish an interaction between the fetal placental villi with the maternal blood supply. When successful, this process enables the transport of oxygen, nutrients, and signaling molecules but an insufficiency leads to placental ischemia. In response, the placenta releases vasoactive factors that enter the maternal circulation and promote maternal cardiorenal dysfunction, a hallmark of preeclampsia (PE), the leading cause of maternal and fetal death. An underexplored mechanism in the development of PE is the impact of membrane-initiated estrogen signaling via the G protein-coupled estrogen receptor (GPER). Recent evidence indicates that GPER activation is associated with normal trophoblast invasion, placental angiogenesis/hypoxia, and regulation of uteroplacental vasodilation, and these mechanisms could explain part of the estrogen-induced control of uterine remodeling and placental development in pregnancy.

CONCLUSION

Although the relevance of GPER in PE remains speculative, this review provides a summary of our current understanding on how GPER stimulation regulates some of the features of normal pregnancy and a potential link between its signaling network and uteroplacental dysfunction in PE. Synthesis of this information will facilitate the development of innovative treatment options.

Reduced right ventricular function on cardiovascular magnetic resonance imaging is associated with uteroplacental impairment in tetralogy of Fallot

BACKGROUND

Maternal right ventricular (RV) dysfunction (measured by echocardiography) is associated with impaired uteroplacental circulation, however echocardiography has important limitations in the assessment of RV function. We therefore aimed to investigate the association of pre-pregnancy RV and left ventricular (LV) function measured by cardiovascular magnetic resonance with uteroplacental Doppler flow parameters in pregnant women with repaired Tetralogy of Fallot (ToF).

METHODS

Women with repaired ToF were examined, who had been enrolled in a prospective multicenter study of pregnant women with congenital heart disease. Clinical data and CMR evaluation before pregnancy were compared with uteroplacental Doppler parameters at 20 and 32 weeks gestation. In particular, pulsatility index (PI) of uterine and umbilical artery were studied.

RESULTS

We studied 31 women; mean age 30 years, operated at early age. Univariable analyses showed that reduced RV ejection fraction (RVEF; P = 0.037 and P = 0.001), higher RV end-systolic volume (P = 0.004) and higher LV end-diastolic and end-systolic volume (P = 0.001 and P = 0.003, respectively) were associated with higher uterine or umbilical artery PI. With multivariable analyses (corrected for maternal age and body mass index), reduced RVEF before pregnancy remained associated with higher umbilical artery PI at 32 weeks (P = 0.002). RVEF was lower in women with high PI compared to women with normal PI during pregnancy (44% vs. 53%, p = 0.022). LV ejection fraction was not associated with uterine or umbilical artery PI.

CONCLUSIONS

Reduced RV function before pregnancy is associated with abnormal uteroplacental Doppler flow parameters. It could be postulated that reduced RV function on pre-pregnancy CMR (≤2 years) is a predisposing factor for impaired placental function in women with repaired ToF.

Evaluation of the effect of metformin and aspirin on utero placental circulation of pregnant women with PCOS

BACKGROUND

Women with polycystic ovary syndrome (PCOS) often are infertile and even if they become pregnant, there are complications with some adverse outcomes. It has been reported that aspirin and metformin improve uteroplacental circulation and reduce pregnancy complications.

OBJECTIVE

To determine and compare uteroplacental circulation and obstetrics complications in pregnant women with PCOS treated with metformin, aspirin and control group.

MATERIALS AND METHODS

105 pregnant women with PCOS were enrolled in this study after assessing uterine artery pulsatility index (PI) with Doppler ultrasonography at 12 weeks of gestation. The patients were divided into three groups and received metformin 2000 mg or aspirin 80 mg daily, or no intervention until the end of pregnancy. PI was assessed for the patients at 20 week of gestation and groups were followed up till delivery. PI and obstetrics complications such as gestational diabetes, preterm labor, preeclampsia and IUGR were compared among groups.

RESULTS

All groups had significant reduction in the mean uterine artery PI at 20 weeks measurement (p<0.05), but this reduction was more in metformin and aspirin groups than control group (p=0.002). There was a significant difference in mean uterine artery PI 20 week of gestation in three groups (p=0.005). Adverse outcomes have seen 4 out of 35 in metformin group, 7 out of 35 in aspirin group and 11 out of 35 in control group. There weren't significant differences among groups (p=0.12).

CONCLUSION

Metformin and low dose aspirin reduced uterine artery impedance but there was not associated with reduced obstetrics complication in women with PCOS.