In studies randomizing pregnant women to glucose-lowering therapy, metformin was associated with lower gestational weight gain and a lower risk of pre-eclampsia compared with insulin.

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Abstract Context Preeclampsia is a leading cardiovascular complication in pregnancy lacking effective diagnostic and treatment strategies. Objective To investigate the diagnostic and therapeutic potential of the angiogenesis markers, FKBPL-CD44, in preeclampsia pathogenesis Design and Intervention FKBPL and CD44 plasma or placental concentration was determined in women pre- or post-diagnosis of preeclampsia. Trophoblast and endothelial cell function was assessed following mesenchymal stem cell (MSC) treatment and in the context of FKBPL signalling. Settings and Participants Human samples pre-diagnosis (15 and 20 weeks’ gestation; n≥57), or post-diagnosis (n=18 for plasma; n=4 for placenta) of preeclampsia were used to determine FKBPL and CD44 concentration, compared to healthy controls. Trophoblast or endothelial cells were exposed to low/high oxygen, and treated with MSC-conditioned media (MSC-CM) or a FKBPL overexpression plasmid. Main outcome Measures Preeclampsia risk stratification and diagnostic potential of FKBPL and CD44 were investigated. MSC treatment effects and FKBPL-CD44 signalling in trophoblast and endothelial cells were assessed. Results The CD44/FKBPL ratio was reduced in placenta and plasma following clinical diagnosis of preeclampsia. At 20 weeks’ gestation, a high plasma CD44/FKBPL ratio was independently associated with the 2.5-fold increased risk of preeclampsia (OR=2.5, 95% CI 1.12-5.41, p=0.02). In combination with high mean arterial blood pressure (MABP > 82.5 mmHg), the risk further increased to 3.9-fold (95% CI 1.30-11.84, p=0.016). Both hypoxia and MSC-based therapy inhibited FKBPL-CD44 signalling enhancing cell angiogenesis. Conclusions The FKBPL-CD44 pathway appears to have a central role in the pathogenesis of preeclampsia, showing promising utilities for early diagnostic and therapeutic purposes.

Purpose of ReviewThe aim of the study is to perform a critical assessment of in vitro models of pre-eclampsia using complementary human and cell line-based studies. Molecular mechanisms involved in spiral uterine artery (SUA) remodelling and trophoblast functionality will also be discussed.Recent FindingsA number of proteins and microRNAs have been implicated as key in SUA remodelling, which could be explored as early biomarkers or therapeutic targets for prevention of pre-eclampsia.SummaryVarious 2D and 3D in vitro models involving trophoblast cells, endothelial cells, immune cells and placental tissue were discussed to elucidate the pathogenesis of pre-eclampsia. Nevertheless, pre-eclampsia is a multifactorial disease, and the mechanisms involved in its pathogenesis are complex and still largely unknown. Further studies are required to provide better understanding of the key processes leading to inappropriate placental development which is the root cause of pre-eclampsia. This new knowledge could identify novel biomarkers and treatment strategies.

Hemochorial placentation is characterized by the development of trophoblast cells specialized to interact with the uterine vascular bed. We utilized trophoblast stem (TS) cell and mutant rat models to investigate regulatory mechanisms controlling trophoblast cell development. TS cell differentiation was characterized by acquisition of transcript signatures indicative of an endothelial cell-like phenotype, which was highlighted by the expression of anticoagulation factors including tissue factor pathway inhibitor (TFPI). TFPI localized to invasive endovascular trophoblast cells of the rat placentation site. Disruption of TFPI in rat TS cells interfered with development of the endothelial cell-like endovascular trophoblast cell phenotype. Similarly, TFPI was expressed in human invasive/extravillous trophoblast (EVT) cells situated within first-trimester human placental tissues and following differentiation of human TS cells. TFPI was required for human TS cell differentiation to EVT cells. We next investigated the physiological relevance of TFPI at the placentation site. Genome-edited global TFPI loss-of-function rat models revealed critical roles for TFPI in embryonic development, resulting in homogeneous midgestation lethality prohibiting analysis of the role of TFPI as a regulator of the late-gestation wave of intrauterine trophoblast cell invasion. In vivo trophoblast-specific TFPI knockdown was compatible with pregnancy but had profound effects at the uterine–placental interface, including restriction of the depth of intrauterine trophoblast cell invasion while leading to the accumulation of natural killer cells and increased fibrin deposition. Collectively, the experimentation implicates TFPI as a conserved regulator of invasive/EVT cell development, uterine spiral artery remodeling, and hemostasis at the maternal–fetal interface.

Diabetes in pregnancy is associated with adverse pregnancy outcomes including preterm birth. Although the mechanisms leading to these pregnancy complications are still poorly understood, aberrant angiogenesis and endothelial dysfunction play a key role. FKBPL and SIRT-1 are critical regulators of angiogenesis, however, their roles in pregnancies affected by diabetes have not been examined before in detail. Hence, this study aimed to investigate the role of FKBPL and SIRT-1 in pre-gestational (type 1 diabetes mellitus, T1D) and gestational diabetes mellitus (GDM). Placental protein expression of important angiogenesis proteins, FKBPL, SIRT-1, PlGF and VEGF-R1, was determined from pregnant women with GDM or T1D, and in the first trimester trophoblast cells exposed to high glucose (25 mM) and varying oxygen concentrations [21%, 6.5%, 2.5% (ACH-3Ps)]. Endothelial cell function was assessed in high glucose conditions (30 mM) and following FKBPL overexpression. Placental FKBPL protein expression was downregulated in T1D (FKBPL; p<0.05) whereas PlGF/VEGF-R1 were upregulated (p<0.05); correlations adjusted for gestational age were also significant. In the presence of GDM, only SIRT-1 was significantly downregulated (p<0.05) even when adjusted for gestational age (r=-0.92, p=0.001). Both FKBPL and SIRT-1 protein expression was reduced in ACH-3P cells in high glucose conditions associated with 6.5%/2.5% oxygen concentrations compared to experimental normoxia (21%; p<0.05). FKBPL overexpression in endothelial cells (HUVECs) exacerbated reduction in tubule formation compared to empty vector control, in high glucose conditions (junctions; p<0.01, branches; p<0.05). In conclusion, FKBPL and/or SIRT-1 downregulation in response to diabetic pregnancies may have a key role in the development of vascular dysfunction and associated complications affected by impaired placental angiogenesis.

The extravillous trophoblast (EVT) cell lineage is a key feature of placentation and critical for spiral artery remodeling and successful pregnancy. Our knowledge of transcriptional regulation driving EVT cell development is limited. Here, we mapped the transcriptome and epigenome landscape as well as chromatin interactions of human trophoblast stem (TS) cells and their transition into the differentiated EVT cell lineage. Chromatin accessibility in intergenic regions was more extensive in EVT cells than in TS cells in the stem state, which is consistent with increased enhancer-driven gene regulation. Using reference epigenome annotation, we noted that 18% of the chromatin landscape in EVT cells was uncharted. We linked regulatory regions to their cognate target genes and characterized the three-dimensional organization of the TS cell functional genome by high throughput chromosome conformation capture. Integration of chromatin accessibility, long-range chromatin interactions, transcriptomic, and transcription factor binding motif enrichment enabled identification of transcription factors and regulatory mechanisms associated with EVT cell lineage development. Subsequent analyses elucidated functional roles for TFAP2C, SNAI1, and EPAS1 in the regulation of EVT cell lineage development. EPAS1 was identified as an upstream regulator of key EVT cell transcription factors, including ASCL2 and SNAI1 and together with its target genes, was linked to diseases of pregnancy, including idiopathic recurrent pregnancy loss and low birth weight. Collectively, we have revealed activation of a dynamic regulatory network that provides a framework for understanding EVT cell specification in trophoblast cell lineage development and human placentation.

Background: Overexpression of sFlt-1 or modulation of FKBPL, key antiangiogenic proteins, are important in the pathogenesis of preeclampsia. Methods: A newly developed nonviral gene-delivery system, RALA, capable of overexpressing sFlt-1 (e15a isoform) was delivered in vivo in transgenic haploinsufficient ( Fkbpl+/−) mice. RALA was also used in vitro to deliver human Flt1 (hFlt1) in trophoblast cells. Results: Serum stable and nontoxic RALA/DNA-based nanoparticles induced an increase in sFlt-1 protein levels in the blood and total protein in the urine; the effect was more pronounced in Fkbpl+/− mice. In vitro, RALA-hFlt nanoparticles significantly reduced secretion of sFlt-1 in trophoblast cells. Conclusion: The RALA-based genetic nanodelivery system can be safely and effectively applied to emulate preeclampsia-like features or reduce sFlt-1 levels in vitro.