Clinical and in Vitro Evidence against Placenta Infection at Term by Severe Acute Respiratory Syndrome Coronavirus 2.

Despite occasional reports of vertical transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during pregnancy, the question of placental infection and its consequences for the newborn remain unanswered. Herein, we analyzed the placentas of 31 coronavirus disease 2019-positive mothers by reverse transcriptase PCR, immunohistochemistry, and in situ hybridization. Only one case of placental infection was detected, which was associated with intrauterine demise of the fetus. Differentiated primary trophoblasts were then isolated from nonpathologic human placentas at term, differentiated, and exposed to SARS-CoV-2 virions. Unlike for positive control cells Vero E6, the virus inside cytotrophoblasts and syncytiotrophoblasts or in the supernatant 4 days after infection was undetectable. As a mechanism of defense, we hypothesized that trophoblasts at term do not express angiotensin-converting enzyme 2 and transmembrane protease serine 2 (TMPRSS2), the two main host membrane receptors for SARS-CoV-2 entry. The quantification of these proteins in the placenta during pregnancy confirmed the absence of TMPRSS2 at the surface of the syncytium. Surprisingly, a transiently induced experimental expression of TMPRSS2 did not allow the entry or replication of the virus in differentiated trophoblasts. Altogether, these results underline that trophoblasts are not likely to be infected by SARS-CoV-2 at term, but raise concern about preterm infection.

Hypoxia-inducible factor 2 alpha impairs human cytotrophoblast syncytialization: New insights into placental dysfunction and fetal growth restriction.

Insufficient remodeling of uterine arteries causes pregnancy-related diseases, including fetal growth restriction and preeclampsia. In these situations, reduced maternal blood flow in the placenta is thought to be responsible for the persistence of a low oxygen environment throughout pregnancy. We hypothesized that chronic activation of transcription factors hypoxia-inducible factors (HIFs) actively participates in placental underdevelopment, which impairs fetal growth. The computer-assisted analysis in pathological placentas revealed an increased number of HIF-2α-positive nuclei in the syncytium compared to normal human placentas, while HIF-1α stabilization was unchanged. Specific involvement of HIF-2α was confirmed in primary human cytotrophoblasts rendered deficient for HIF1A or HIF2A. Silencing HIF2A increased the expression of main syncytialization markers as well as differentiation and syncytium formation. It also improved placental growth factor bioavailability. None of these changes was seen when silencing HIF1A. Conversely, the experimental induction of HIF-2α expression repressed forskolin-induced differentiation in BeWo choriocarcinoma cells. Our mechanistic insights evidence that transcription factor HIF-2α impairs placental function, thus suggesting its participation in fetal growth restriction and preeclampsia when placentas become chronically hypoxic. Furthermore, it suggests the possibility to develop novel molecular targeting therapies for placental dysfunction.

Impaired vascular endothelial growth factor expression and secretion during in vitro differentiation of human primary term cytotrophoblasts.

Vascular endothelial growth factor A (VEGF-A) is one of the main growth factors involved in placental vasculogenesis and angiogenesis, but its placental expression is still ambiguous. During in vitro cultures of primary term cytotrophoblasts, VEGF could not be detected in the supernatants by enzyme-linked immunosorbent assays (ELISA). One hypothesis is that VEGF is immediately and completely bound to its soluble receptor after secretion, and cannot be recognized by the antibodies used in the commercial ELISA kits. We decided to verify this hypothesis by measuring VEGF-A expression during in vitro cultures of primary term cytotrophoblasts. Term cytotrophoblasts were cultured under 21% and 2.5% O2 for 4 days. VEGF-A transcripts were quantified by real-time polymerase chain reaction. The proteins from cell lysates and concentrated media were separated by polyacrylamide gel electrophoresis (PAGE) under denaturing and reducing conditions, and VEGF-A immunodetected by western blotting. VEGF mRNA expression did not increase during in vitro cell differentiation under 21% O2, but slightly increased under 2.5% O2 only at 24 h. VEGF-A monomer was not detected in the cell lysates and in the concentrated supernatants, while a ~ 42 KDa band corresponding to the precursor L-VEGF was detected in all the cellular extracts. Isolated term villous cytotrophoblasts produce the L-VEGF precursor but they do not secrete VEGF-A even under low-oxygen tension. The question remains about the origin of VEGF in pregnancy but also about the biological role of L-VEGF, which can represent a form of storage for rapid VEGF secretion when needed.

Effects of chemotherapy on placental development and function using in vitro culture of human primary cytotrophoblasts.

Introduction Cancers during pregnancy can be treated with chemotherapy after the first trimester but the treatment is associated with smaller placentas and an increased risk of stillbirth, fetal growth retardation and preterm delivery. We decided to assess the effect of several chemotherapeutic agents on placental development by using in vitro culture of human term cytotrophoblasts. Methods Cytotrophoblasts isolated from term placentas were cultured for 48 h and treated for 24 h with epirubicin, docetaxel, vinblastine, methotrexate, tamoxifen, 4-hydroxytamoxifen, and endoxifen. First, cell viability was assessed. Then, the effect of the treatment on trophoblast differentiation and placental angiogenesis was assessed by quantifying hCG and PlGF mRNA and protein expression. Finally, the expression of two efflux transporters, BCRP and MDR1 was investigated. Results Epirubicin only strongly decreased cell viability. Epirubicin, docetaxel, and vinblastine inhibited HCGB and PlGF expression while methotrexate, tamoxifen and its two metabolites increased it. BCRP was essentially expressed in syncytiotrophoblasts and MDR1 in undifferentiated cytotrophoblasts. Their expression was not affected by the drugs but vinblastine increased BCRP mRNA expression by 2.8-fold. Discussion The most commonly used chemotherapeutic drugs are well supported in vitro by syncytiotrophoblasts, except for epirubicin, which was very cytotoxic. Chemotherapy perturbed the expression of genes normally upregulated during placental differentiation and angiogenesis but not the expression of the drug transporters. Further studies looking at the effect of combination therapy and the transporter capacities to reject the drugs will be needed to better define the effects of chemotherapy on placental development and function.

Anomalies of the placenta and umbilical cord in twin gestations.

The frequency of twin gestations has increased over the last few decades, mainly due to maternal age at childbearing, and the use of assisted reproductive technologies. Twins are at higher risk of aneuploidy, structural anomalies, and placental abnormalities. Some of the placental and umbilical cord abnormalities found in twin gestations are nonspecific and can be found in singleton gestations (ie, placenta previa, placental abruption, single umbilical artery, velamentous cord insertion, vasa previa, etc). However, other anomalies are unique to twin gestations, and are mainly associated with monochorionic twins-these include intraplacental anastomosis and cord entanglement. Most of these conditions can be diagnosed with ultrasound. An accurate and early diagnosis is important in the management of twin gestations. Determination of chorionicity, amnionicity, and the identification of placental anomalies are key issues for the adequate management of twin pregnancies. Pathologic placental examination after delivery can help in assessing the presence of placental and umbilical cord abnormalities, as well as providing information about chorionicity and gaining insight into the potential mechanisms of disease affecting twin gestations.

Inhibin alpha gene expression in human trophoblasts is regulated by interactions between TFAP2 and cAMP signaling pathways.

Inhibin α (Inha) gene expression is regulated, in rat granulosa cells, via a cyclic 3',5'-adenosine monophosphate (AMP)-response element (CRE) found in a region of the promoter that is homologous to the human INHA promoter. We previously found that during in vitro cytotrophoblast differentiation, human INHA gene expression was regulated by TFAP2A via association with an AP-2 site located upstream of this CRE. The aim of this study was to evaluate if the human INHA gene was also regulated by cAMP in trophoblasts, and to investigate the possible crosstalk between TFAP2 and cAMP signaling pathways in the regulation of INHA gene expression. Treatment with cAMP or forskolin increased INHA mRNA expression by 7- and 2-fold in primary cytotrophoblasts and choriocarcinoma-derived BeWo cells, respectively. Treatment with the protein kinase A inhibitor H-89 reduced forskolin-induced luciferase activity by ∼40% in BeWo cells transfected with an INHA promoter-driven luciferase reporter vector. TFAP2 overexpression increased basal luciferase activity, whereas the dominant repressor KCREB abolished it. Surprisingly, mutation of the CRE also eliminated the TFAP2-induced transcription, although TFAP2 overexpression was still able to increase forskolin-induced luciferase activity when the AP-2 binding site, but not the CRE site, was mutated. Thus, INHA gene expression is upregulated by cAMP via CRE in human trophoblasts, and TFAP2 regulates this expression by interacting with CRE.

Gene therapy in preeclampsia: the dawn of a new era.

Preeclampsia is a severe complication of pregnancy, affecting an estimated 4 million women annually. It is one of the leading causes of maternal and fetal mortality worldwide, and it has life-long consequences. The maternal multisystemic symptoms are driven by poor placentation, which causes syncytiotrophoblastic stress and the release of factors into the maternal bloodstream. Amongst them, the soluble fms-like tyrosine kinase-1 (sFLT-1) triggers extensive endothelial dysfunction by acting as a decoy receptor for the vascular endothelial growth factor (VEGF) and the placental growth factor (PGF). Current interventions aim to mitigate hypertension and seizures, but the only definite treatment remains induced delivery. Thus, there is a pressing need for novel therapies to remedy this situation. Notably, CBP-4888, a siRNA drug delivered subcutaneously to knock down sFLT1 expression in the placenta, has recently obtained Fast Track approval from the Food and Drug Administration (FDA) and is undergoing a phase 1 clinical trial. Such advance highlights a growing interest and significant potential in gene therapy to manage preeclampsia. This review summarizes the advances and prospects of gene therapy in treating placental dysfunction and illustrates crucial challenges and considerations for these emerging treatments.

Twin-to-twin transfusion syndrome: perinatal outcome and recipient heart disease according to treatment strategy.

AIM: The aims of the study were to compare perinatal outcome and assess recipient cardiac disease according to treatment strategy (amnioreduction (AR), laser or selective feticide). METHODS: We retrospectively reviewed 81 consecutive cases of twin-to-twin transfusion syndrome diagnosed before 28 weeks between 1993 and 2007. RESULTS: Although fetuses treated by laser were younger at diagnosis (median 20.4 vs. 22.4 weeks, P = 0.01), they were significantly older at birth (median 33.6 vs. 28.5 weeks, P = 0.004) than those treated by AR. Neonatal morbidity was globally lower after laser than AR, and cardiac insufficiency tended to be less frequent (31% vs. 57%, P = 0.09). There was a trend towards increased perinatal survival after laser treatment (68% vs. 49%, P = 0.1). Heart failure was the cause of death in half (23/46) of the recipients. Fetal heart failure leading to death was 2.7 times more frequent after AR than after laser (n = 11 vs. n = 4), and all four neonatal cardiac deaths occurred after AR. Compared with laser, selective feticide did not further improve the outcome. CONCLUSIONS: Heart failure was an important cause of perinatal morbidity and death. However, laser therapy resulted in a longer diagnosis-delivery interval and lower global neonatal morbidity than AR, with a trend towards increased perinatal survival. Improved outcome after laser treatment compared with AR might be related to its impact on recipient heart disease.

Specific HIF-2α (Hypoxia-Inducible Factor-2) Inhibitor PT2385 Mitigates Placental Dysfunction In Vitro and in a Rat Model of Preeclampsia (RUPP).

BACKGROUND: Preeclampsia is one of the leading causes of maternal mortality worldwide and is strongly associated with long-term morbidity in mothers and newborns. Referred to as one of the deep placentation disorders, insufficient remodeling of the spiral arteries during the first trimester remains a major cause of placental dysfunction. Persisting pulsatile uterine blood flow causes abnormal ischemia/reoxygenation phenomenon in the placenta and stabilizes the HIF-2α (hypoxia-inducible factor-2α) in the cytotrophoblasts. HIF-2α signaling impairs trophoblast differentiation and increases sFLT-1 (soluble fms-like tyrosine kinase-1) secretion, which reduces fetal growth and causes maternal symptoms. This study aims to evaluate the benefits of using PT2385-an oral specific HIF-2α inhibitor-to treat severe placental dysfunction. METHODS: To evaluate its therapeutic potential, PT2385 was first studied in primary human cytotrophoblasts isolated from term placenta and exposed to 2.5% O2 to stabilize HIF-2α. Viability and luciferase assays, RNA sequencing, and immunostaining were used to analyze differentiation and angiogenic factor balance. The ability of PT2385 to mitigate maternal manifestations of preeclampsia was studied in the selective reduced uterine perfusion pressure model performed in Sprague-Dawley rats. RESULTS: In vitro, RNA sequencing analysis and conventional techniques showed that treated cytotrophoblast displayed an enhanced differentiation into syncytiotrophoblasts and normalized angiogenic factor secretion compared with vehicle-treated cells. In the selective reduced uterine perfusion pressure model, PT2385 efficiently decreased sFLT-1 production, thus preventing the onset of hypertension and proteinuria in pregnant dams. CONCLUSIONS: These results highlight HIF-2α as a new player in our understanding of placental dysfunction and support the use of PT2385 to treat severe preeclampsia in humans.

Pregnancy Outcomes After Kidney Transplantation and Long-Term Evolution of Children: A Single Center Experience.

BACKGROUND: Pregnancies in women who underwent kidney transplants are at high risk compared with the general population. METHODS: In this study, we aimed to retrospectively assess the obstetrical complications, delivery outcomes, and impact of pregnancy on kidney allograft function in a single-center cohort of kidney transplant recipients (KTRs). We provide data regarding the long-term evolution of children. RESULTS: Thirty-two KTRs underwent a total of 57 pregnancies between 1994 and 2010. Fourteen pregnancies (24 %) did not survive caused by miscarriages (n = 9), stillborn (n = 1), ectopic pregnancies (n = 2), and medical abortion (n = 2). Live birth occurred in 76% of pregnancies. Delivery was by cesarean in 66%. The mean gestational age was 30.45 ± 11.3 weeks and 65% of newborns were premature. A low birth weight <2500g was noted in 46%. Obstetric complications were de novo hypertension in 4%, pre-eclampsia in 9%, and gestational diabetes in 2%. The 5- and 10-year post-delivery death-censored graft loss rates were 3.1% and 12.5%, respectively. Data on 21 children were collected via a self-questionnaire. After a median follow-up time of 17 years, they appeared in good medical and psychological health. None of them suffered from chronic disease (especially uronephrological condition) or was taking chronic medication. CONCLUSIONS: Long-term evolution of children born to women who underwent kidney transplants seems favorable. Pregnancies in KTRs are successful in two-thirds of cases but are at increased risk of prematurity, delivery by cesarean, and low birth weight.

Evaluation of a universal real-time polymerase chain reaction for detection of amniotic fluid infection in premature rupture of membranes.

Managing preterm rupture of membranes (PPROM) is a balance between benefits of prolonging gestation and the risks of perinatal infection. This study evaluates a real-time polymerase chain reaction (PCR) for the detection of amniotic fluid infection and neonatal complications by amniocentesis following PPROM. A total of 61 singleton pregnancies with PPROM were analyzed retrospectively, including histopathologic examination of the placenta and neonatal complications. The real-time PCR detects a highly conserved sequence of the bacterial 16S ribosomal DNA, and its efficacy was compared with standard tests including amniotic fluid glucose concentration, lactate dehydrogenase level, and maternal white cells count and C-reactive protein levels. Sensitivity and specificity were similar for PCR (64% and 85%) and standard tests (58% and 80%). However, the PCR technique has the additional advantage of possible identification of the bacteria through sequencing and has a much better positive predictive value in the occurrence of neonatal complications (60% for PCR versus 35% for standard tests). The latency period between premature rupture of the membranes and delivery was not related to the incidence of histopathologic signs of infection in the placenta or the umbilical cord and was inversely related to the incidence of neonatal complications.

Isolation of Primary Cytotrophoblasts From Human Placenta at Term.

The placenta is a multifaceted organ, fulfilling critical functions for the fetus and the mother. Therefore, it is a critical regulator of the pregnancy, and its dysfunction leads to diseases, including fetal growth restriction and preeclampsia. Studying the placenta is a difficult task since its existence is transient, and its structure is specific to our species. In vitro differentiation of primary cytotrophoblast isolated from term human placenta has been widely used in the placental research field as it represents a reliable model to study cellular differentiation and function. Direct alternatives include trophoblastic cell lines, explants, and organoids, but this protocol, based on the separation of the cells on a Percoll gradient, presents the advantage of being relatively cheap and easy to perform in every research laboratory. Furthermore, the 2D culture is a flexible method that can be adapted to various experimental conditions (transfection, drug exposure, metabolic study, observations, etc.), allowing mechanistic explorations of cellular processes.

Pregnancy, a unique case of heterochronic parabiosis and peripartum cardiomyopathy.

Introduction: A loss of endogenous stem cells capable of tissue repair and regeneration drives the biological process that we recognize as "aging". Recovery of stem cell-mediated repair and regenerative functions in aged animals has been reported in murine heterochronic parabiosis experiments. Objectives: Herein we will review how pregnancy is an unusual form of heterochronic parabiosis, as the placenta prevents the exchange of most blood cells between parabionts. Instead, plasma and its content, including small extracellular vesicles, can readily cross the placental barrier. These nanosized extracellular vesicles are readily produced by the placenta, amnion, fetus and mother, and are essential for fetal organogenesis, growth and the progression of a healthy pregnancy. If defective, these extracellular vesicles can cause havoc such as in the case of peripartum cardiomyopathy. We will also review how these extracellular vesicles impact the mother substantially (including cardiac function) in the parabiosis of pregnancy. Conclusion: Extracellular vesicles generated during the course of a healthy pregnancy are essential for organogenesis and fetal growth, and also for maternal tissue repair and regeneration, and might be defective or deficient in pregnancies that result in peripartum cardiomyopathy.

Outcome of 100 pregnancies initiated under treatment with cabergoline in hyperprolactinaemic women.

CONTEXT: Data concerning the safety for pregnancy of cabergoline treatment in hyperprolactinaemic women are still scarce. OBJECTIVE: To exclude a higher than normal risk for miscarriage and congenital malformation in pregnancies initiated under cabergoline treatment. DESIGN: A retrospective study of 100 pregnancies in 72 hyperprolactinaemic women treated with cabergoline at the time of conception and follow-up of the 88 newborn children. METHODS: Cabergoline was interrupted in 99 pregnancies and continued in one case. Foetal exposure dose to cabergoline was calculated for each pregnancy. Complications of pregnancy and neonatal status were compared to those observed in an age-and delivery time-matched control group of 163 women. RESULTS: The mean foetal exposure dose to cabergoline was 3.6 +/- 4.7 mg. The rate of spontaneous miscarriages was 10%. Three medical terminations of pregnancy were performed for a foetal malformation (3%). Minor to moderate complications were observed in 31% of the pregnancies, a figure similar to that found in the control group. An increase in tumour size (2-8 mm) was observed in 17/37 evaluated cases, needing reintroduction of cabergoline during pregnancy in five patients. The 84 deliveries resulted in 88 infants, three of them presenting with a malformation (3.4%). Neonatal status was comparable to the control group, where a malformation rate of 6.3% was observed. Postnatal development of the children was normal. CONCLUSION: Cabergoline treatment at the time of conception appears to be safe for both the pregnancy and the neonate, although more data are still needed on a larger number of pregnancies.

A systematic approach to first-trimester ultrasound assessment of twins.

The incidence of twin pregnancies has increased for the last 20 years mainly as a result of assisted reproduction technologies and pregnancies occurring in older women. Both maternal and perinatal mortality and morbidity are increased in twin pregnancies when compared with singletons. A systematic and detailed first-trimester ultrasound can be a useful tool for detecting chorionicity, growth discordance, and congenital malformations. Prediction of complications at an early stage can help with directing future management and counseling of patients.

Transabdominal cerclage for cervical insufficiency in twins: series of seven cases and literature review.

Background: The diagnosis of cervical insufficiency is based on the previous history of recurrent second or early third trimester losses. Its incidence among pregnant women is 0.5-1% but can be as high as 75% among women with preterm birth. Transvaginal cerclage (TVC) is the common therapy of cervical insufficiency. However, this technique has several limits, especially in twin pregnancies. As some selected conditions, a transabdominal cerclage (TAC) is indicated, it has been offered to patients with multiple pregnancies.Aim: To evaluate the outcomes of twin pregnancies with transabdominal cerclage in terms of preterm birth rate and neonatal morbidity and mortality.Materials and methods: We conducted a retrospective study of seven patients with twin pregnancies managed with transabdominal cerclage at the end of the first trimester (12-15 weeks). We selected patients with a history of fetal loss who met the indications criteria of TAC (history of TVC failure or short cervix unable to have TVC). The antenatal and delivery data were collected and compared to those of their previous pregnancy.Outcomes: All patients carried their pregnancy throughout the second trimester and delivered during the third trimester. Mean gestational age was 34 4/7 week. All newborns were alive and neonatal morbidity rate was 50%, mostly related to preterm birth. Mean duration of neonatal intensive care stay was 32 days. There were no operative complications following TAC.Conclusions: Perinatal outcomes are considerably improved in twin pregnancies with transabdominal cerclage. Our findings corroborate those of previous case reports and support the efficacy of TAC for managing cervical insufficiency in twin pregnancies.

Prenatal diagnosis of fetal cataract: case report and review of the literature.

OBJECTIVES: To report a case of prenatally diagnosed fetal cataract and conduct a systematic review of previously reported cases. METHODS: Review of the literature based mainly on Pubmed search using specific keywords in order to list cataract causes diagnosed prenatally and in early childhood, isolated or associated with microphthalmia. RESULTS AND DISCUSSION: A differential diagnosis list and specific prenatal diagnosis testing are suggested in order to offer the best management of this rare fetal condition.

Changes in fetal membrane histology with cervical insufficiency and transabdominal cerclage.

OBJECTIVE: To determine whether term fetal membranes from transabdominal cerclage (TAC) patients have favorable characteristics compared with membranes from patients without TAC. METHODS: A prospective study of consecutive pregnant women who had undergone TAC and were delivered by elective cesarean after 37 weeks before the onset of labor at Cliniques universitaires Saint-Luc, Brussels, between January 2015 and June 2016. Membranes were collected from two areas: overlying the cervix and located far from the cervix. Membrane thickness, 15-hydroxyprostaglandin dehydrogenase (PGDH), toll-like receptor-2 (TLR2) expression, and senescence were measured and compared between the TAC group and a control group without TAC enrolled using the same study criteria. RESULTS: In the cervical area of the TAC group, the chorion was significantly thicker (P=0.003). PGDH and TLR2 expression were also significantly increased in the cervical area of the TAC group (P=0.021 and P=0.043, respectively). Senescence was significantly decreased in the TAC group (P=0.001). CONCLUSION: A significant relationship between chorion thickening and increase in PGDH and TLR2 expression and decrease in senescence was reported in the cervical area of membranes in the TAC group. These membrane changes could prevent triggering of parturition and may account for favorable outcomes and clinical success in pregnancies with TAC.