Compromised SARS-CoV-2-specific placental antibody transfer.

SARS-CoV-2 infection causes more severe disease in pregnant women compared to age-matched non-pregnant women. Whether maternal infection causes changes in the transfer of immunity to infants remains unclear. Maternal infections have previously been associated with compromised placental antibody transfer, but the mechanism underlying this compromised transfer is not established. Here, we used systems serology to characterize the Fc profile of influenza-, pertussis-, and SARS-CoV-2-specific antibodies transferred across the placenta. Influenza- and pertussis-specific antibodies were actively transferred. However, SARS-CoV-2-specific antibody transfer was significantly reduced compared to influenza- and pertussis-specific antibodies, and cord titers and functional activity were lower than in maternal plasma. This effect was only observed in third-trimester infection. SARS-CoV-2-specific transfer was linked to altered SARS-CoV-2-antibody glycosylation profiles and was partially rescued by infection-induced increases in IgG and increased FCGR3A placental expression. These results point to unexpected compensatory mechanisms to boost immunity in neonates, providing insights for maternal vaccine design.

Fc Glycan-Mediated Regulation of Placental Antibody Transfer.

Despite the worldwide success of vaccination, newborns remain vulnerable to infections. While neonatal vaccination has been hampered by maternal antibody-mediated dampening of immune responses, enhanced regulatory and tolerogenic mechanisms, and immune system immaturity, maternal pre-natal immunization aims to boost neonatal immunity via antibody transfer to the fetus. However, emerging data suggest that antibodies are not transferred equally across the placenta. To understand this, we used systems serology to define Fc features associated with antibody transfer. The Fc-profile of neonatal and maternal antibodies differed, skewed toward natural killer (NK) cell-activating antibodies. This selective transfer was linked to digalactosylated Fc-glycans that selectively bind FcRn and FCGR3A, resulting in transfer of antibodies able to efficiently leverage innate immune cells present at birth. Given emerging data that vaccination may direct antibody glycosylation, our study provides insights for the development of next-generation maternal vaccines designed to elicit antibodies that will most effectively aid neonates.

Fc Characteristics Mediate Selective Placental Transfer of IgG in HIV-Infected Women.

The placental transfer of maternal IgG is critical for infant protection against infectious pathogens. However, factors that modulate the placental transfer of IgG remain largely undefined. HIV-infected women have impaired placental IgG transfer, presenting a unique "disruption model" to define factors that modulate placental IgG transfer. We measured the placental transfer efficiency of maternal HIV and pathogen-specific IgG in US and Malawian HIV-infected mothers and their HIV-exposed uninfected and infected infants. We examined the role of maternal HIV disease progression, infant factors, placental Fc receptor expression, IgG subclass, and glycan signatures and their association with placental IgG transfer efficiency. Maternal IgG characteristics, such as binding to placentally expressed Fc receptors FcγRIIa and FcγRIIIa, and Fc region glycan profiles were associated with placental IgG transfer efficiency. Our findings suggest that Fc region characteristics modulate the selective placental transfer of IgG, with implications for maternal vaccine design and infant health.

Conditionally mutant animal model for investigating the invasive trophoblast cell lineage.

Placental development involves coordinated expansion and differentiation of trophoblast cell lineages possessing specialized functions. Among the differentiated trophoblast cell lineages are invasive trophoblast cells, which exit the placenta and invade the uterus, where they restructure the uterine parenchyma and facilitate remodeling of uterine spiral arteries. The rat exhibits deep intrauterine trophoblast cell invasion, a feature shared with human placentation, and is also amenable to gene manipulation using genome-editing techniques. In this investigation, we generated a conditional rat model targeting the invasive trophoblast cell lineage. Prolactin family 7, subfamily b, member 1 (Prl7b1) is uniquely and abundantly expressed in the rat invasive trophoblast cell lineage. Disruption of Prl7b1 did not adversely affect placental development. We demonstrated that the Prl7b1 locus could be effectively used to drive the expression of Cre recombinase in invasive trophoblast cells. Our rat model represents a new tool for investigating candidate genes contributing to the regulation of invasive trophoblast cells and their roles in trophoblast-guided uterine spiral artery remodeling.

A conserved role of the Hippo signalling pathway in initiation of the first lineage specification event across mammals.

Our understanding of the molecular events driving cell specification in early mammalian development relies mainly on mouse studies, and it remains unclear whether these mechanisms are conserved across mammals, including humans. We have shown that the establishment of cell polarity via aPKC is a conserved event in the initiation of the trophectoderm (TE) placental programme in mouse, cow and human embryos. However, the mechanisms transducing cell polarity into cell fate in cow and human embryos are unknown. Here, we have examined the evolutionary conservation of Hippo signalling, which is thought to function downstream of aPKC activity, in four different mammalian species: mouse, rat, cow and human. In all four species, inhibition of the Hippo pathway by targeting LATS kinases is sufficient to drive ectopic TE initiation and downregulation of SOX2. However, the timing and localisation of molecular markers differ across species, with rat embryos more closely recapitulating human and cow developmental dynamics, compared with the mouse. Our comparative embryology approach uncovered intriguing differences as well as similarities in a fundamental developmental process among mammals, reinforcing the importance of cross-species investigations.

CRISPR screening in human trophoblast stem cells reveals both shared and distinct aspects of human and mouse placental development.

The placenta serves as the interface between the mother and fetus, facilitating the exchange of gases and nutrients between their separate blood circulation systems. Trophoblasts in the placenta play a central role in this process. Our current understanding of mammalian trophoblast development relies largely on mouse models. However, given the diversification of mammalian placentas, findings from the mouse placenta cannot be readily extrapolated to other mammalian species, including humans. To fill this knowledge gap, we performed CRISPR knockout screening in human trophoblast stem cells (hTSCs). We targeted genes essential for mouse placental development and identified more than 100 genes as critical regulators in both human hTSCs and mouse placentas. Among them, we further characterized in detail two transcription factors, DLX3 and GCM1, and revealed their essential roles in hTSC differentiation. Moreover, a gene function-based comparison between human and mouse trophoblast subtypes suggests that their relationship may differ significantly from previous assumptions based on tissue localization or cellular function. Notably, our data reveal that hTSCs may not be analogous to mouse TSCs or the extraembryonic ectoderm (ExE) in which in vivo TSCs reside. Instead, hTSCs may be analogous to progenitor cells in the mouse ectoplacental cone and chorion. This finding is consistent with the absence of ExE-like structures during human placental development. Our data not only deepen our understanding of human trophoblast development but also facilitate cross-species comparison of mammalian placentas.

Genomics, the diversification of mammals, and the evolution of placentation.

When and why did variations in placental structure and function evolve? Such questions cannot be addressed without a reliable version of mammalian phylogeny. Twenty-five years ago, the mammalian tree was reshaped by molecular phylogenetics. Soon it was shown, in contrast to prevailing theories, that the common ancestor of placental mammals had invasive placentation. Subsequently, evolution of many other features of extraembryonic membranes was addressed. This endeavour stimulated research to fill gaps in our knowledge of placental morphology. Last year the mammalian tree was again revised based on a large set of genomic data. With that in mind, this review provides an update on placentation in the nineteen orders of placental mammals, incorporating much recent data. The principal features such as shape, interdigitation, the interhaemal barrier and the yolk sac are summarized in synoptic tables. The evolution of placental traits and its timing is then explored by reference to the revised mammalian tree. Examples are the early appearance of epitheliochorial placentation in the common ancestor of artiodactyls, perissodactyls, pangolins and carnivores (with reversion to invasive forms in the latter) and later refinements such as the binucleate trophoblast cells and placentomes of ruminants. In primates, the intervillous space gradually evolved from the more basic labyrinth whereas trophoblast invasion of the decidua was a late development in humans and great apes. Only seldom can we glimpse the "why" of placental evolution. The best examples concern placental hormones, including some striking examples of convergent evolution such as the chorionic gonadotropins of primates and equids. In concluding, I review current ideas about what drives placental evolution and identify significant gaps in our knowledge of placentation, including several relevant to the evolution of placentation in primates.

Why study human embryo development?

Understanding the processes and mechanisms underlying early human embryo development has become an increasingly active and important area of research. It has potential for insights into important clinical issues such as early pregnancy loss, origins of congenital anomalies and developmental origins of adult disease, as well as fundamental insights into human biology. Improved culture systems for preimplantation embryos, combined with the new tools of single cell genomics and live imaging, are providing new insights into the similarities and differences between human and mouse development. However, access to human embryo material is still restricted and extended culture of early embryos has regulatory and ethical concerns. Stem cell-derived models of different phases of human development can potentially overcome these limitations and provide a scalable source of material to explore the early postimplantation stages of human development. To date, such models are clearly incomplete replicas of normal development but future technological improvements can be envisaged. The ethical and regulatory environment for such studies remains to be fully resolved.

Clinical impact of additional findings detected by genome-wide non-invasive prenatal testing: Follow-up results of the TRIDENT-2 study.

In the TRIDENT-2 study, all pregnant women in the Netherlands are offered genome-wide non-invasive prenatal testing (GW-NIPT) with a choice of receiving either full screening or screening solely for common trisomies. Previous data showed that GW-NIPT can reliably detect common trisomies in the general obstetric population and that this test can also detect other chromosomal abnormalities (additional findings). However, evidence regarding the clinical impact of screening for additional findings is lacking. Therefore, we present follow-up results of the TRIDENT-2 study to determine this clinical impact based on the laboratory and perinatal outcomes of cases with additional findings. Between April 2017 and April 2019, additional findings were detected in 402/110,739 pregnancies (0.36%). For 358 cases, the origin was proven to be either fetal (n = 79; 22.1%), (assumed) confined placental mosaicism (CPM) (n = 189; 52.8%), or maternal (n = 90; 25.1%). For the remaining 44 (10.9%), the origin of the aberration could not be determined. Most fetal chromosomal aberrations were pathogenic and associated with severe clinical phenotypes (61/79; 77.2%). For CPM cases, occurrence of pre-eclampsia (8.5% [16/189] vs 0.5% [754/159,924]; RR 18.5), and birth weight <2.3rd percentile (13.6% [24/177] vs 2.5% [3,892/155,491]; RR 5.5) were significantly increased compared to the general obstetric population. Of the 90 maternal findings, 12 (13.3%) were malignancies and 32 (35.6%) (mosaic) pathogenic copy number variants, mostly associated with mild or no clinical phenotypes. Data from this large cohort study provide crucial information for deciding if and how to implement GW-NIPT in screening programs. Additionally, these data can inform the challenging interpretation, counseling, and follow-up of additional findings.

Dysregulation of integrin αvß3 and α5ß1 impedes migration of placental endothelial cells in fetal growth restriction.

Placentas from pregnancies complicated by severe early-onset fetal growth restriction (FGR) exhibit diminished vascular development mediated by impaired angiogenesis, but underlying mechanisms remain unknown. In this study, we show that FGR endothelial cells demonstrate inherently reduced migratory capacity despite the presence of fibronectin, a matrix protein abundant in placental stroma that displays abnormal organization in FGR placentas. Thus, we hypothesized that aberrant endothelial-fibronectin interactions in FGR are a key mechanism underlying impaired FGR endothelial migration. Using human fetoplacental endothelial cells isolated from uncomplicated term control and FGR pregnancies, we assessed integrin α5ß1 and αvß3 regulation during cell migration. We show that endothelial integrin α5ß1 and αvß3 interactions with fibronectin are required for migration and that FGR endothelial cells responded differentially to integrin inhibition, indicating integrin dysregulation in FGR. Whole-cell expression was not different between groups. However, there were significantly more integrins in focal adhesions and reduced intracellular trafficking in FGR. These newly identified changes in FGR endothelial cellular processes represent previously unidentified mechanisms contributing to persistent angiogenic deficiencies in FGR.

DNA methylation-mediated 11ßHSD2 downregulation drives the increases in angiotensin-converting enzyme and angiotensin II within preeclamptic placentas.

Preeclampsia (PE) is a complex human-specific complication frequently associated with placental pathology. The local renin-angiotensin system (RAS) in the human placenta, which plays a crucial role in regulating placental function, has been extensively documented. Glucocorticoids (GCs) are a class of steroid hormones. PE cases often have abnormalities in GCs levels and placental GCs barrier. Despite extensive speculation, there is currently no robust evidence indicating that GCs regulate placental RAS. This study aims to investigate these potential relationships. Plasma and placental samples were collected from both normal and PE pregnancies. The levels of angiotensin-converting enzyme (ACE), angiotensin II (Ang II), cortisol, and 11ß-hydroxysteroid dehydrogenases (11ßHSD) were analyzed. In PE placentas, cortisol, ACE, and Ang II levels were elevated, while 11ßHSD2 expression was reduced. Interestingly, a positive correlation was observed between ACE and cortisol levels in the placenta. A significant inverse correlation was found between the methylation statuses within the 11ßHSD2 gene promoter and its expression, meanwhile, 11ßHSD2 expression was negatively correlated with cortisol and ACE levels. In vitro experiments using placental trophoblast cells confirmed that active GCs can stimulate ACE transcription and expression through the GR pathway. Furthermore, 11ßHSD2 knockdown could enhance this activating effect. An in vivo study using a rat model of intrauterine GCs overexposure during mid-to-late gestation suggested that excess GCs in utero lead to increased ACE and Ang II levels in the placenta. Collectively, this study provides the first evidence of the relationships between 11ßHSD2 expression, GCs barrier, ACE, and Ang II levels in the placenta. It not only contributes to understanding the pathological features of the placental GCs barrier and RAS under PE conditions, also provides important information for revealing the pathological mechanism of PE.

Association between placental oxygen transport and fetal brain cortical development: a study in monochorionic diamniotic twins.

Normal cortical growth and the resulting folding patterns are crucial for normal brain function. Although cortical development is largely influenced by genetic factors, environmental factors in fetal life can modify the gene expression associated with brain development. As the placenta plays a vital role in shaping the fetal environment, affecting fetal growth through the exchange of oxygen and nutrients, placental oxygen transport might be one of the environmental factors that also affect early human cortical growth. In this study, we aimed to assess the placental oxygen transport during maternal hyperoxia and its impact on fetal brain development using MRI in identical twins to control for genetic and maternal factors. We enrolled 9 pregnant subjects with monochorionic diamniotic twins (30.03 ± 2.39 gestational weeks [mean ± SD]). We observed that the fetuses with slower placental oxygen delivery had reduced volumetric and surface growth of the cerebral cortex. Moreover, when the difference between placenta oxygen delivery increased between the twin pairs, sulcal folding patterns were more divergent. Thus, there is a significant relationship between placental oxygen transport and fetal brain cortical growth and folding in monochorionic twins.

The GPI-anchor biosynthesis pathway is critical for syncytiotrophoblast differentiation and placental development.

The glycosylphosphatidylinositol (GPI) biosynthetic pathway in the endoplasmic reticulum (ER) is crucial for generating GPI-anchored proteins (GPI-APs), which are translocated to the cell surface and play a vital role in cell signaling and adhesion. This study focuses on two integral components of the GPI pathway, the PIGL and PIGF proteins, and their significance in trophoblast biology. We show that GPI pathway mutations impact on placental development impairing the differentiation of the syncytiotrophoblast (SynT), and especially the SynT-II layer, which is essential for the establishment of the definitive nutrient exchange area within the placental labyrinth. CRISPR/Cas9 knockout of Pigl and Pigf in mouse trophoblast stem cells (mTSCs) confirms the role of these GPI enzymes in syncytiotrophoblast differentiation. Mechanistically, impaired GPI-AP generation induces an excessive unfolded protein response (UPR) in the ER in mTSCs growing in stem cell conditions, akin to what is observed in human preeclampsia. Upon differentiation, the impairment of the GPI pathway hinders the induction of WNT signaling for early SynT-II development. Remarkably, the transcriptomic profile of Pigl- and Pigf-deficient cells separates human patient placental samples into preeclampsia and control groups, suggesting an involvement of Pigl and Pigf in establishing a preeclamptic gene signature. Our study unveils the pivotal role of GPI biosynthesis in early placentation and uncovers a new preeclampsia gene expression profile associated with mutations in the GPI biosynthesis pathway, providing novel molecular insights into placental development with implications for enhanced patient stratification and timely interventions.

Transforming growth factor-ß signaling governs the differentiation program of extravillous trophoblasts in the developing human placenta.

Abnormal placentation has been noticed in a variety of pregnancy complications such as miscarriage, early-onset preeclampsia, and fetal growth restriction. Defects in the developmental program of extravillous trophoblasts (EVTs), migrating from placental anchoring villi into the maternal decidua and its vessels, is thought to be an underlying cause. Yet, key regulatory mechanisms controlling commitment and differentiation of the invasive trophoblast lineage remain largely elusive. Herein, comparative gene expression analyses of HLA-G-purified EVTs, isolated from donor-matched placenta, decidua, and trophoblast organoids (TB-ORGs), revealed biological processes and signaling pathways governing EVT development. In particular, bioinformatics analyses and manipulations in different versatile trophoblast cell models unraveled transforming growth factor-ß (TGF-ß) signaling as a crucial pathway driving differentiation of placental EVTs into decidual EVTs, the latter showing enrichment of a secretory gene signature. Removal of Wingless signaling and subsequent activation of the TGF-ß pathway were required for the formation of human leukocyte antigen-G+ (HLA-G+) EVTs in TB-ORGs that resemble in situ EVTs at the level of global gene expression. Accordingly, TGF-ß-treated EVTs secreted enzymes, such as DAO and PAPPA2, which were predominantly expressed by decidual EVTs. Their genes were controlled by EVT-specific induction and genomic binding of the TGF-ß downstream effector SMAD3. In summary, TGF-ß signaling plays a key role in human placental development governing the differentiation program of EVTs.

Vertical Transmission of SARS-CoV-2-Specific Antibodies and Cytokine Profiles in Pregnancy.

Despite intensive characterization of immune responses after COVID-19 infection and vaccination, research examining protective correlates of vertical transmission in pregnancy are limited. Herein, we profiled humoral and cellular characteristics in pregnant women infected or vaccinated at different trimesters and in their corresponding newborns. We noted a significant correlation between spike S1-specific IgG antibody and its RBD-ACE2 blocking activity (receptor-binding domain-human angiotensin-converting enzyme 2) in maternal and cord plasma (P < .001, R > 0.90). Blocking activity of spike S1-specific IgG was significantly higher in pregnant women infected during the third trimester than the first and second trimesters. Elevated levels of 28 cytokines/chemokines, mainly proinflammatory, were noted in maternal plasma with infection at delivery, while cord plasma with maternal infection 2 weeks before delivery exhibited the emergence of anti-inflammatory cytokines. Our data support vertical transmission of protective SARS-CoV-2-specific antibodies. This vertical antibody transmission and the presence of anti-inflammatory cytokines in cord blood may offset adverse outcomes of inflammation in exposed newborns.

Proteomic Analysis Reveals Differential Protein Expression in Placental Tissues of Early-Onset Preeclampsia Patients.

Preeclampsia, a significant cause of maternal and perinatal morbidity and mortality, remains poorly understood, in terms of its pathogenesis. This study aims to uncover novel and effective biomarkers for preeclampsia by conducting a comparative analysis of differential proteins in placentas from early onset preeclampsia (EOPE) and normal pregnancies. Utilizing tandem mass tag (TMT)-based quantitative proteomics, we identified differentially expressed proteins in placental tissues from 15 EOPE patients and 15 normal pregnant women. These proteins were subsequently validated by using parallel reaction monitoring (PRM). Our analysis revealed a total of 59 differentially expressed proteins, with 25 up-regulated and 34 down-regulated proteins in EOPE placental tissues compared to those from normal pregnancies. Validation through PRM confirmed the differential expression of 6 proteins. Our findings suggest these 6 proteins could play crucial roles in the pathogenesis of EOPE, highlighting the potential involvement of the estrogen signaling pathway and dilated cardiomyopathy (DCM) pathway in the development of preeclampsia. The data were deposited with the ProteomeXchange Consortium via the iProX partner repository with the identifier PXD055025.

Maternal-fetal interfaces transcriptome changes associated with placental insufficiency and a novel gene therapy intervention.

The etiology of fetal growth restriction (FGR) is multifactorial, although many cases involve placental insufficiency. Placental insufficiency is associated with inadequate trophoblast invasion resulting in high resistance to blood flow, decreased availability of nutrients, and increased hypoxia. We have developed a non-viral, polymer-based nanoparticle that facilitates delivery and transient gene expression of human insulin-like 1 growth factor (hIGF1) in trophoblast for the treatment of placenta insufficiency and FGR. Using the established guinea pig maternal nutrient restriction (MNR) model of placental insufficiency, the aim of the study was to identify novel pathways in the sub-placenta/decidua that provide insight into the underlying mechanism driving placental insufficiency, and may be corrected with hIGF1 nanoparticle treatment. Pregnant guinea pigs underwent ultrasound-guided sham or hIGF1 nanoparticle treatment at mid-pregnancy, and sub-placenta/decidua tissue was collected 5 days later. Transcriptome analysis was performed using RNA Sequencing on the Illumina platform. The MNR sub-placenta/decidua demonstrated fewer maternal spiral arteries lined by trophoblast, shallower trophoblast invasion and downregulation of genelists involved in the regulation of cell migration. hIGF1 nanoparticle treatment resulted in marked changes to transporter activity in the MNR + hIGF1 sub-placenta/decidua when compared to sham MNR. Under normal growth conditions however, hIGF1 nanoparticle treatment decreased genelists enriched for kinase signaling pathways and increased genelists enriched for proteolysis indicative of homeostasis. Overall, this study identified changes to the sub-placenta/decidua transcriptome that likely result in inadequate trophoblast invasion and increases our understanding of pathways that hIGF1 nanoparticle treatment acts on in order to restore or maintain appropriate placenta function.

The RhoA guanine exchange factor ABR: a glucose-sensitive mediator of actin reorganization in feto-placental arterial endothelial cells altered by gestational diabetes mellitus.

In utero exposure to gestational diabetes mellitus (GDM) programs the fetus, increasing offspring risk for endothelial dysfunction and cardiovascular disease later in life. Hyperglycaemia is widely recognized as the driving force of diabetes-induced programming. We have previously shown that GDM exposure alters DNA methylation and gene expression associated with actin remodelling in primary feto-placental arterial endothelial cells (fpEC). Thus, we hypothesized that hyperglycaemic insults underlie programmed changes in fpEC morphology and actin organization by GDM. Therefore, arterial fpECs isolated after normal and GDM pregnancy, as well as normal fpECs that were exposed to hyperglycaemia in vitro, were analysed for the effect of GDM and hyperglycaemia on actin organization and network formation. Integration of gene expression and DNA methylation data identified the RhoA activator active BCR-related (ABR) as programmed by GDM and altered by in vitro hyperglycaemia. ABR silencing in GDM-exposed cells reduced RhoA activity by 34 ± 26% (P = 0.033) and restored normal fpEC phenotype. In fact, in vitro hyperglycaemia induced a similar fpEC phenotype as intrauterine exposure to GDM, i.e. round morphology and increased network formation on Matrigel by 34 ± 33% (P = 0.022) vs. 22 ± 20% for GDM (P = 0.004). Thus, we identified ABR as a novel glucose sensitive regulator of actin organization and cell shape, programmed by GDM and upregulated by hyperglycaemia. Identification of mechanisms induced by hyperglycaemia and affecting endothelial function in the long term will contribute to understanding GDM-induced programming of offspring endothelial dysfunction and cardiovascular disease. Future studies could focus on investigating the prevention or reversal of such malprogramming. KEY POINTS: In utero exposure to gestational diabetes mellitus (GDM) affects future health of the offspring, with an increased risk for endothelial dysfunction and cardiovascular disease in later life. GDM alters DNA methylation and expression of ABR in feto-placental arterial endothelial cells (fpEC), a model for endothelial cells exposed to the intrauterine environment of the fetus. GDM phenotype of fpECs is also induced by hyperglycaemia in vitro, and is characterized by altered actin organization and cell shape, which can be restored by ABR silencing. Revealing the cellular mechanisms induced by GDM and hyperglycaemia is important for understanding the mechanisms of how these conditions disturb endothelial function in the offspring.

Characterization of human placental fetal vessels in gestational diabetes mellitus.

Gestational diabetes mellitus is one of the most common complications during pregnancy. Its prevalence is rapidly increasing worldwide. Gestational diabetes mellitus is leading to an elevated risk for the development of endothelial dysfunction and cardiovascular diseases both in the mother and the child in later life. The underlying pathophysiological mechanisms are not well-understood. Therefore, we aimed to characterize the endothelial function in fetal placental vessels from mothers with gestational diabetes mellitus. In this study, we distinguished between insulin-treated and diet-controlled gestational diabetes mothers and compared them to a normoglycemic control group. The clinical data confirmed pre-conceptional overweight as a risk factor in women with insulin-treated gestational diabetes mellitus. The insulin-treated gestational diabetes group was also characterized by a recent family history of diabetes compared to mothers of the control or diet-controlled gestational diabetes group. Analyses of blood serum from umbilical cords suggested a reduced fetal insulin metabolism in the insulin-treated gestational diabetes group. Vascular function analysis in fetal placental vessels revealed an altered substance P-induced vasorelaxation in vessels from patients with insulin-dependent gestational diabetes. Inhibition of nitric oxide synthase affected only fetal vessel segments from the control group or diet-controlled gestational diabetes group, but not from insulin-dependent gestational diabetes. Finally, we found a significantly decreased substance P receptor (TACR1) mRNA expression in fetal vessel segments from patients with insulin-treated gestational diabetes. In conclusion, we provide evidence that different pathophysiological mechanisms might be responsible for the development of insulin-treated versus diet-controlled gestational diabetes. Only in fetal vessels from patients with insulin-treated gestational diabetes were we able to detect an endothelial dysfunction and a reduced fetal insulin conversion. This provides novel insights into the pathophysiology of the subtypes of gestational diabetes.

Placental ischemia-upregulated angiotensin II type 1 receptor in hypothalamic paraventricular nucleus contributes to hypertension in rat.

Preeclampsia (PE) is associated with increased angiotensin II sensitivity and poor neurological outcomes marked by temporal loss of neural control of blood pressure. Yet the role of centrally expressed angiotensin II type 1 receptor (AT1R) within the paraventricular nucleus of the hypothalamus (PVN) in the PE model is not understood. In a PE rat model with reduced placental perfusion pressure (RUPP) induced on gestational day 14 (GD14), the PVN expression and cellular localization of AT1R were assessed using immunofluorescence and western blotting. The sensitivity of RUPP to acute angiotensin II infusion was assessed. AT1R was antagonized by losartan (100 µg/kg/day) for 5 days intracerebroventricularly (ICV). Hemodynamic data and samples were collected on GD19 for further analysis. RUPP upregulated (p < 0.05) mRNA and protein of AT1R within the PVN and lowered (p < 0.05) circulating angiotensin II in rats. RUPP increased neural and microglial activation. Cellular localization assessment revealed that AT1R was primarily expressed in neurons and slightly in microglia and astrocytes. Infusion of 100 ng/kg as bolus increased the mean arterial pressure (MAP in mmHg) in both RUPP and Sham. ICV losartan infusion attenuated RUPP-increased MAP (113.6 ± 6.22 in RUPP vs. 92.16 ± 5.30 in RUPP + Los, p = 0.021) and the expression of nuclear transcription factor NF-κB, tyrosine hydroxylase (TH), NADPH oxidase 4 (NOX4) and reactive oxygen species (ROS) in the PVN. Our data suggest that centrally expressed AT1R, within the PVN, contributes to placental ischemia-induced hypertension in RUPP rats highlighting its therapeutic potential in PE.