The thrombomodulin-protein C system is essential for the maintenance of pregnancy

Combined Anticoagulant Therapy for Prevention of Preeclampsia and Small for Gestational Age Neonates: A Systematic Review and Meta-analysis

OBJECTIVE

This systematic review and meta-analysis (SRMA) aims to compare the efficacy of combining low molecular weight heparin (LMWH) and aspirin against aspirin alone in preventing preeclampsia (PE) and small for gestational age (SGA) neonates in women at moderate and high risks.

STUDY DESIGN

The included studies were nonrandomized and randomized clinical trials (RCTs) enrolling women at moderate and high risks for developing preeclampsia. PubMed/Medline, Cochrane Library, Embase, and Grey literature (including ClinicalTrials.gov) were searched.

RESULTS

Out of 4,762 records, 7 nonrandomized studies and 12 RCTs (enrolling 545 and 1,677 women, respectively) were selected. Although the studies were clinically heterogeneous, the conduction of quantitative analysis was feasible. Regarding RCTs, the odds of early-onset preeclampsia was reduced by 89% (pooled odds ratio [OR] = 0.11, 95% confidence interval [CI]: 0.01-0.93, p = 0.04) in women with thrombophilia, the incidence of SGA neonates below the 5th percentile by 48% (pooled OR = 0.52, 95% CI: 0.28-0.96, p = 0.04) in women with a history of preeclampsia and/or SGA neonates, and the incidence of SGA neonates below the 10th percentile by 31% (pooled OR = 0.69, 95% CI: 0.50-0.96, p = 0.03) in the whole population.

CONCLUSION

Concerning the whole studied population, combined anticoagulant therapy is not superior to aspirin alone. However, it may be more effective in preventing early-onset preeclampsia regarding women with thrombophilia, SGA neonates below the 5th percentile regarding women with a history of preeclampsia and/or SGA, and SGA neonates below the 10th percentile in moderate- or high-risk women. The above mixed but promising results need to be envisaged with caution due to the clinical heterogeneity of the included studies which is the main limitation of our research. Nevertheless, the strict and narrow inclusion search criteria, and the appropriate subgroup analysis are its main strengths. More RCTs with homogeneous populations and stricter inclusion criteria are needed to confirm these results.

KEY POINTS

· Combined therapy is not superior to aspirin alone.. · Combined therapy in women with thrombophilia may protect against early-onset preeclampsia.. · Combined therapy in moderate/high-risk women may protect against SGA <10th percentile neonates..

The severity of chronic histiocytic intervillositis is associated with gestational age and fetal weight

INTRODUCTION

Chronic histiocytic intervillositis (CHI) is a rare histopathological lesion in the placenta that is associated with poor reproductive outcomes. The intervillous infiltrate consists mostly of maternal mononuclear cells and fibrin depositions, which are both indicators for the severity of the intervillous infiltrate. The severity of the intervillous infiltrate as well as the clinical outcomes of pregnancy differ between cases. Our objective is to determine the relation between the severity of the intervillous infiltrate and the clinical outcomes of CHI.

METHODS

Cases of CHI were semi-quantitatively graded based on histopathological severity scores. Hereto, CD68 positive mononuclear cells were quantified, fibrin depositions visualized by both a PTAH stain and an immuohistochemical staining, and placental dysfunction was assessed via thrombomodulin staining.

RESULTS

This study included 36 women with CHI. A higher CD68 score was significantly associated with a lower birthweight. Loss of placental thrombomodulin was associated with lower gestational age, lower birthweight, and a lower placenta weight. The combined severity score based on CD68 and PTAH was significantly associated with fetal growth restriction, and the joint score of CD68 and fibrin was associated with birthweight and placental weight.

DISCUSSION

More severe intervillous infiltrates in CHI placentas is associated with a lower birth weight and placental weight. Furthermore, this study proposes thrombomodulin as a possible new severity marker of placental damage. More research is needed to better understand the pathophysiology of CHI.

Animal Models of Cardiovascular Complications of Pregnancy

Cardiovascular complications of pregnancy have risen substantially over the past decades, and now account for the majority of pregnancy-induced maternal deaths, as well as having substantial long-term consequences on maternal cardiovascular health. The causes and pathophysiology of these complications remain poorly understood, and therapeutic options are limited. Preclinical models represent a crucial tool for understanding human disease. We review here advances made in preclinical models of cardiovascular complications of pregnancy, including preeclampsia and peripartum cardiomyopathy, with a focus on pathological mechanisms elicited by the models and on relevance to human disease.

Thrombomodulin and pregnancy in the limelight: Insights into the therapeutic aspect of thrombomodulin in pregnancy complications

BACKGROUND

Thrombomodulin (TM) is a transmembrane glycoprotein expressed on the endothelial cell functioning as a cofactor in the anticoagulation system. However, aside from anticoagulation, recent studies have revealed its multiple organ protective roles such as anti-inflammation, angiogenesis, and cell proliferation, which may redefine the function of TM. Although TM is predominantly expressed on placental trophoblasts, the physiological role of TM during pregnancy remains unclear. Because the understanding of TM function has drastically progressed, these new discoveries shed light on the unknown activities of placental TM. Moreover, the clinical application of recombinant TM (rTM) has opened the possibility of TM as a therapeutic target for pregnancy complications.

OBJECTIVES

Here, we comprehensively review the studies elucidating the role of TM during pregnancy from both classic and newly discovered perspectives, and seek for its potential as a therapeutic target for pregnancy complications.

METHODS

Basic research using trophoblast cells and transgenic mice, as well as cohort studies of inherited TM deficiency and clinical trials of rTM were summarized, which led us to further discuss the clinical application of rTM as a novel therapeutic for pregnancy complications.

RESULTS AND CONCLUSION

Accumulating evidence suggest the relevance of placental TM deficiency in pregnancy complications such as miscarriage, fetal growth restriction, and preeclampsia. Most importantly, promising results in animal studies and clinical trials further assure the possibility of rTM as an optimal therapeutic for such conditions. The therapeutic potential of TM raised throughout this review could drastically change the clinical approach to pregnancy complication and improve maternal outcomes.

Expression of tissue factor and TF-mediated integrin regulation in HTR-8/SVneo trophoblast cells

Placenta is a crucial source of Tissue Factor (TF) to initiate coagulation. As far as the TF is concern, aberrant expression of TF has been reported to have a significant role in thrombosis, inflammation, cancer metastasis and atherosclerosis. It is evident that TF and TF-FVIIa complex has major roles in the disease process beyond hemostasis and thrombosis. On the other hand, TF-FVII-dependent signaling primarily activates PAR2 and inducing pro-angiogenic and immune-modulating cytokines in tumor environment. However, the role of TF has not been delineated in placental functions. Integrin typically binds to the extracellular matrix which in turn mediate cell-cell adhesion and cell behavior for migration. Dysregulation of integrin expression affects cell interaction, proliferation, and migration. Therefore, this study aims to ascertain the expression of TF in HTR-8/SVneo trophoblast cell line and its role in signal transduction of integrin (ITGα1, ITGα2, ITGβ1) regulation concerning the invasion of trophoblasts. We have used RT-PCR and Western blot for the gene and protein expression analysis respectively. In addition, cell migration assays, MTT, and DAPI were performed to examine migration, cytotoxicity and apoptosis effect of FVIIa. The results suggest that the gene and protein level expressions of TF were predominant in HTR-8/SVneo cell line. Further, the cytotoxicity and apoptosis in HTR-8/SVneo cells were not observed when treated with FVIIa. The cells treated with FVIIa shown a dose-dependent up-regulation of integrin(s) (**p < 0.01, *p < 0.05) when compared to control. Migration of the HTR-8/SVneo cells was observed without any apoptosis in FVIIa-treated cells when compared to that of control. On the whole, these observations delineated the TF-FVIIa interaction in modulating the TF-dependent integrin signal transduction in HTR-8/SVneo trophoblast cell line.

Gestational hemostasis: a natural model for hemostasis resuscitation of major periprocedural blood loss : "Look deep into nature, and then you will understand everything better." Albert Einstein

Early goal-directed treatment is an evidence-based approach to guide hemostatic therapy during major periprocedural bleeding. If viscoelastic coagulation tests are not available, an algorithm, termed the pyramid of hemostatic interventions, can help manage severe bleeding. Pregnant women accumulate huge reserves of prothrombotic and antifibrinolytic hemostatic elements to avoid peripartum blood loss. We provide comparison of therapeutic hemostatic approaches and natural gestational process and identified remarkable analogy between early goal-directed management of bleeding and hemostatic adaptation of pregnant woman. Therefore, gestational hemostasis serves as a natural model for goal-directed hemostasis resuscitation and can foster understanding of hemostatic management of periprocedural bleeding.

Maternal platelets at the first trimester maternal-placental interface - Small players with great impact on placenta development

In human pregnancy, maternal platelet counts decrease with each trimester, reaching a reduction by approximately ten percent at term in uncomplicated cases and recover to the levels of the non-pregnant state a few weeks postpartum. The time when maternal platelets start to occur in the early human placenta most likely coincides with the appearance of loosely cohesive endovascular trophoblast plugs showing capillary-sized channels by mid first trimester. At that time, platelets accumulate in intercellular gaps of anchoring parts of trophoblast columns and start to adhere to the surface of placental villi and the chorionic plate. This is considered as normal process that contributes to placenta development by acting on both the extravillous- and the villous trophoblast compartment. Release of platelet cargo into intercellular gaps of anchoring cell columns may affect partial epithelial-to-mesenchymal transition and invasiveness of extravillous trophoblasts as well as deposition of fibrinoid in the basal plate. Activation of maternal platelets on the villous surface leads to perivillous fibrin-type fibrinoid deposition, contributing to the shaping of the developing placental villi and the intervillous space. In contrast, excess platelet activation at the villous surface leads to deregulation of the endocrine activity, sterile inflammation and local apoptosis of the syncytiotrophoblast. Platelets and their released cargo are adapted to pregnancy, and may be altered in high-risk pregnancies. Identification of different maternal platelet subpopulations, which show differential procoagulant ability and different response to anti-platelet therapy, are promising new future directions in deciphering the role of maternal platelets in human placenta physiology.

Relationship between second-trimester amniotic fluid and plasma levels of angiopoietin-2 and thrombomodulin with adverse pregnancy outcome

Our objective is to investigate maternal midtrimester plasma and amniotic fluid (AF) levels of angiopoietin-2 (Ang-2) and thrombomodulin (TM), which are involved in vascular remodelling and endothelium activation, in placental disorders including foetal growth restriction (FGR) and preeclampsia (PE). This prospective multiparametric pilot study was conducted at the Perinatology Division of Trakya University in a population undergoing genetic amniocentesis. Both AF and plasma aliquots were kept in -80 °C until ELISA assay. The pregnancies were followed up until the end of gestation in terms of obstetric results. Amniotic fluid and plasma aliquots from 127 pregnancies who underwent genetic amniocentesis between 16 and 24 weeks of gestation were analysed. During the final data evaluation, 39 were excluded with various reasons. Twelve subsequently developed FGR and 11 complicated with PE. The control group (n = 65) was consisted of women delivered >37th week with an uncomplicated outcome. The midtrimester maternal Ang-2 levels in both AF and plasma and also TM levels in plasma were found to be significantly increased in pregnancies who subsequently developed FGR or PE (p< .05). The midtrimester Ang-2, which rises in both plasma and AF and the midtrimester TM, which only significantly increase in plasma compartment in PE group, as compensatory mechanism may be the precursors of placental disorders including FGR and PE.Impact StatementWhat is already known on this subject? It is known that angiopoietin-2 (Ang-2) has important role in placental angiogenesis and vascular remodelling. TM which is a receptor for Ang-2 plays a protective role in pregnancy by preventing the uteroplacental circulation from thrombosis.What do the results of this study add? The present study demonstrates that both midtrimester maternal plasma Ang-2/TM and amniotic fluid (AF) Ang-2 levels were significantly higher in PE and FGR group than uncomplicated group. Midtrimester AF TM levels were not significantly higher in PE group than the control group.What the implications are of these findings for clinical practice and/or further research? In the clinical practice, high levels of midtrimester Ang-2 and TM in plasma may be used for the prediction of FGR and PE. Although amniocentesis is not practical in the clinical use, the levels of these two markers in both AF and plasma compartments may contribute to explain the pathophysiology of FGR and PE.

A novel homozygous variant of the thrombomodulin gene causes a hereditary bleeding disorder

We report a 19-year-old Vietnamese woman who experienced several life-threatening bleeding events, including ovarian hemorrhage. Blood analysis revealed a decreased fibrinogen level with markedly elevated fibrinogen/fibrin degradation products and D-dimer levels. Despite hemostatic surgery and administration of several medications, such as nafamostat mesylate, tranexamic acid, and unfractionated heparin, the coagulation abnormalities were not corrected, and the patient experienced repeated hemorrhagic events. We found that administration of recombinant human thrombomodulin (rhTM) remarkably improved the patient's pathophysiology. Screening and sequencing of the TM gene (THBD) revealed a previously unreported homozygous variation: c.793T>A (p.Cys265Ser). Notably, the Cys265 residue forms 1 of 3 disulfide bonds in the epidermal growth factor (EGF)-like domain 1 of TM. Transient expression experiments using COS-1 cells demonstrated markedly reduced expression of TM-Cys265Ser on the plasma membrane relative to wild-type TM. The TM-Cys265Ser mutant was intracellularly degraded, probably because of EGF-like domain 1 misfolding. The reduced expression of TM on the endothelial cell membrane may be responsible for the disseminated intravascular-coagulation-like symptoms observed in the patient. In summary, we identified a novel TM variant, c.793T>A (p.Cys265Ser). Patients homozygous for this variant may present with severe bleeding events; rhTM should be considered a possible treatment option for these patients.

Thrombomodulin promotes placental function by up-regulating placental growth factor via inhibition of high-mobility-group box 1 and hypoxia-inducible factor 1α

INTRODUCTION

Pregnancy is a state of maternal systemic stress due to inflammation and hypoxic reactions originating from the utero-placental unit. Maternal tolerance to these stresses is a key for successful outcomes. Thrombomodulin (TM), a glycoprotein expressed on cell surface, regulates local inflammatory pathways by inhibiting proinflammatory factor, High-mobility-group box1(HMGB1). Although TM is highly expressed on placental trophoblast cells, biological activities of TM during pregnancy remains unclear. Here, we hypothesized that TM may contribute to the maternal stress coping mechanisms.

METHODS

By administering recombinant-TM (rTM) to the pregnant mice, we investigated the influence of TM functions on the placenta and fetal growth. We further examined its effect on trophoblast cells, focusing on HMGB1-regulated inflammatory signalings and hypoxia-inducible factor 1α (HIF1α)-dependent regulation of placental angiogenic factors.

RESULTS

Administration of rTM increased fetal weight and fetal/placental-weight ratios, which implies the improvement of placental function. These features were accompanied by maternal serum HMGB1 reduction and suppressed placental proinflammatory cytokine, IL-6 and TNF-α, expressions. In addition, rTM reduced HIF1α protein accumulation and enhanced placental growth factor (PlGF) expression in the placenta, that explains the improvement of maternal features.

DISCUSSION

Our study revealed the supportive effect of TM on the placental function in mice. By inhibiting HMGB1, rTM suppresses proinflammatory cytokines, downregulates HIF1α and induces PlFG expression in the placental tissue. Our results have elucidated the novel aspects of TM; the regulation of placental inflammatory cytokines and angiogenic factors, during pregnancy. These findings may reveal potential therapeutic opportunities for the management of maternal complications.

Immunohistochemical analysis of thrombomodulin expression in myocardial tissue from autopsy cases of ischemic heart disease

Thrombomodulin is a transmembrane glycoprotein that is ubiquitously expressed on the surface of vascular endothelial cells. Thrombomodulin exerts its anticoagulant effects by combining with thrombin, activating protein C, and inactivating the coagulation factors FVa and FVIIIa. Clinically, thrombomodulin is also known as a marker of vascular injury because it circulates freely in response to endothelial injury. In this study, myocardial tissue from cases of ischemic heart disease was subjected to immunohistochemistry by thrombomodulin. We examined 40 neutral-formalin-fixed, paraffin-embedded myocardial tissue samples from autopsy cases that were diagnosed with ischemic heart disease (within 48 h postmortem). Thrombomodulin expression was observed in vascular endothelial cells between myocardial cells and in mesothelial cells of the epicardium. In necrotic myocardium, diffusion of thrombomodulin, which reflected endothelial injury, was observed. Upregulated thrombomodulin expression was observed around myocardial cells under ongoing remodeling, which suggested endothelial proliferation in these locations. Completed fibrotic foci of the myocardium did not show upregulated thrombomodulin expression. In a mouse model of acute myocardial infarction, the same phenomena as that found in human samples were observed by immunohistochemistry of thrombomodulin. Immunostaining of thrombomodulin, as a marker for endothelial injury or myocardial remodeling, may be useful for supplementing conventional staining techniques in the diagnosis of ischemic heart disease in forensic pathology.

Lipid presentation by the protein C receptor links coagulation with autoimmunity

Antiphospholipid antibodies (aPLs) cause severe autoimmune disease characterized by vascular pathologies and pregnancy complications. Here, we identify endosomal lysobisphosphatidic acid (LBPA) presented by the CD1d-like endothelial protein C receptor (EPCR) as a pathogenic cell surface antigen recognized by aPLs for induction of thrombosis and endosomal inflammatory signaling. The engagement of aPLs with EPCR-LBPA expressed on innate immune cells sustains interferon- and toll-like receptor 7-dependent B1a cell expansion and autoantibody production. Specific pharmacological interruption of EPCR-LBPA signaling attenuates major aPL-elicited pathologies and the development of autoimmunity in a mouse model of systemic lupus erythematosus. Thus, aPLs recognize a single cell surface lipid-protein receptor complex to perpetuate a self-amplifying autoimmune signaling loop dependent on the cooperation with the innate immune complement and coagulation pathways.

X chromosome-dependent disruption of placental regulatory networks in hybrid dwarf hamsters

Embryonic development in mammals is highly sensitive to changes in gene expression within the placenta. The placenta is also highly enriched for genes showing parent-of-origin or imprinted expression, which is predicted to evolve rapidly in response to parental conflict. However, little is known about the evolution of placental gene expression, or if divergence of placental gene expression plays an important role in mammalian speciation. We used crosses between two species of dwarf hamsters (Phodopus sungorus and Phodopus campbelli) to examine the genetic and regulatory underpinnings of severe placental overgrowth in their hybrids. Using quantitative genetic mapping and mitochondrial substitution lines, we show that overgrowth of hybrid placentas was primarily caused by genetic differences on the maternally inherited P. sungorus X chromosome. Mitochondrial interactions did not contribute to abnormal hybrid placental development, and there was only weak correspondence between placental disruption and embryonic growth. Genome-wide analyses of placental transcriptomes from the parental species and first- and second-generation hybrids revealed a central group of co-expressed X-linked and autosomal genes that were highly enriched for maternally biased expression. Expression of this gene network was strongly correlated with placental size and showed widespread misexpression dependent on epistatic interactions with X-linked hybrid incompatibilities. Collectively, our results indicate that the X chromosome is likely to play a prominent role in the evolution of placental gene expression and the accumulation of hybrid developmental barriers between mammalian species.

Placental thromboinflammation impairs embryonic survival by reducing placental thrombomodulin expression

Excess platelet activation by extracellular vesicles (EVs) results in trophoblast inflammasome activation, interleukin 1β (IL-1β) activation, preeclampsia (PE), and partial embryonic lethality. Embryonic thrombomodulin (TM) deficiency, which causes embryonic lethality hallmarked by impaired trophoblast proliferation, has been linked with maternal platelet activation. We hypothesized that placental TM loss, platelet activation, and embryonic lethality are mechanistically linked to trophoblast inflammasome activation. Here, we uncover unidirectional interaction of placental inflammasome activation and reduced placental TM expression: although inflammasome inhibition did not rescue TM-null embryos from lethality, the inflammasome-dependent cytokine IL-1β reduced trophoblast TM expression and impaired pregnancy outcome. EVs, known to induce placental inflammasome activation, reduced trophoblast TM expression and proliferation. Trophoblast TM expression correlated negatively with IL-1β expression and positively with platelet numbers and trophoblast proliferation in human PE placentae, implying translational relevance. Soluble TM treatment or placental TM restoration ameliorated the EV-induced PE-like phenotype in mice, preventing placental thromboinflammation and embryonic death. The lethality of TM-null embryos is not a consequence of placental NLRP3 inflammasome activation. Conversely, EV-induced placental inflammasome activation reduces placental TM expression, promoting placental and embryonic demise. These data identify a new function of placental TM in PE and suggest that soluble TM limits thromboinflammatory pregnancy complications.

Expression of Pinopodes in the Endometrium from Recurrent Pregnancy Loss Women. Role of Thrombomodulin and Ezrin

BACKGROUND

Pinopode expression has been suggested as a marker of endometrial receptivity.

METHODS

We set up an experimental study comparing endometrial tissue from recurrent pregnancy loss (RPL, n = 30) and fertile control (CTR, n = 20) women in terms of pinopode expression/morphology; expression of thrombomodulin (TM) and ezrin; cytoskeletal organization. Endometrial samples were collected during implantation window and evaluated by scanning electron microscopy, western blot, and immunofluorescence.

RESULTS

We found that RPL endometrial tissue showed: (i) increased pinopodes density (* p < 0.05); (ii) a reduced diameter of pinopodes (* p < 0.05); (iii) a decreased TM and ezrin expression (p < 0.05). Additionally, confocal images showed a significantly reduced expression of phosphorylated (p)-ezrin, confirming the results obtained through immunoblot analysis. Immunofluorescence staining showed that in CTR samples, junctions between cells are intact and clearly visible, whereas actin filaments appear completely lost in RPL endometrial samples; this suggests that, due to the impaired expression and activity of TM and ezrin, actin does not bind to plasma membrane in order to orchestrate the cytoskeletal actin filaments.

CONCLUSIONS

Our findings suggest that an impaired expression of TM and expression/activation of ezrin may affect the connection between the TM and actin cytoskeleton, impairing the organization of cytoskeleton and, eventually, the adequate pinopode development.

Podocyte Integrin-β 3 and Activated Protein C Coordinately Restrict RhoA Signaling and Ameliorate Diabetic Nephropathy

BACKGROUND

Diabetic nephropathy (dNP), now the leading cause of ESKD, lacks efficient therapies. Coagulation protease-dependent signaling modulates dNP, in part via the G protein-coupled, protease-activated receptors (PARs). Specifically, the cytoprotective protease-activated protein C (aPC) protects from dNP, but the mechanisms are not clear.

METHODS

A combination of in vitro approaches and mouse models evaluated the role of aPC-integrin interaction and related signaling in dNP.

RESULTS

The zymogen protein C and aPC bind to podocyte integrin-β ₃, a subunit of integrin-α _v β ₃. Deficiency of this integrin impairs thrombin-mediated generation of aPC on podocytes. The interaction of aPC with integrin-α _v β ₃ induces transient binding of integrin-β ₃ with G _α13 and controls PAR-dependent RhoA signaling in podocytes. Binding of aPC to integrin-β ₃ via its RGD sequence is required for the temporal restriction of RhoA signaling in podocytes. In podocytes lacking integrin-β ₃, aPC induces sustained RhoA activation, mimicking the effect of thrombin. In vivo, overexpression of wild-type aPC suppresses pathologic renal RhoA activation and protects against dNP. Disrupting the aPC-integrin-β ₃ interaction by specifically deleting podocyte integrin-β ₃ or by abolishing aPC's integrin-binding RGD sequence enhances RhoA signaling in mice with high aPC levels and abolishes aPC's nephroprotective effect. Pharmacologic inhibition of PAR1, the pivotal thrombin receptor, restricts RhoA activation and nephroprotects RGE-aPC^high and wild-type mice.Conclusions aPC-integrin-α _v β ₃ acts as a rheostat, controlling PAR1-dependent RhoA activation in podocytes in diabetic nephropathy. These results identify integrin-α _v β ₃ as an essential coreceptor for aPC that is required for nephroprotective aPC-PAR signaling in dNP.

From Anti-SARS-CoV-2 Immune Responses to COVID-19 via Molecular Mimicry

Aim: To define the autoimmune potential of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection. Methods: Experimentally validated epitopes cataloged at the Immune Epitope DataBase (IEDB) and present in SARS-CoV-2 were analyzed for peptide sharing with the human proteome. Results: Immunoreactive epitopes present in SARS-CoV-2 were mostly composed of peptide sequences present in human proteins that—when altered, mutated, deficient or, however, improperly functioning—may associate with a wide range of disorders, from respiratory distress to multiple organ failure. Conclusions: This study represents a starting point or hint for future scientific–clinical investigations and suggests a range of possible protein targets of autoimmunity in SARS-CoV-2 infection. From an experimental perspective, the results warrant the testing of patients’ sera for autoantibodies against these protein targets. Clinically, the results warrant a stringent surveillance on the future pathologic sequelae of the current SARS-CoV-2 pandemic.

The role of haemostasis in placenta-mediated complications

Normal pregnancy is associated with an increasing state of activation of the haemostatic system. This activation state is excessive in women with placenta-mediated pregnancy complications (PMPCs), including preeclampsia (PE). Platelet activation plays a crucial pathophysiological role in PE. The very early activation of coagulation in the intervillous space is mandatory for placental growth and morphogenesis but its excesses and/or inadequate control may participate to the emergence of the trophoblastic phenotype of PE. Extracellular vesicles, of endothelial but also of trophoblastic origin, can favour key cellular reactions of preeclampsia, acting as proactive cofactors. The understanding of this intricate relationship between haemostasis activation and PMPCs may provide interesting keys for new pathophysiological therapeutic developments.

Spontaneous embryo resorption in the mouse is triggered by embryonic apoptosis followed by rapid removal via maternal sterile purulent inflammation

Background

In normal mammalian development a high percentage of implantations is lost by spontaneous resorption. This is a major problem in assisted reproduction and blastocyst transfer. Which embryo will be resorbed is unpredictable. Resorption is very fast, so that with conventional methods only final haemorrhagic stages are encountered.

Here we describe the histology and immunohistochemistry of 23 spontaneous embryo resorptions between days 7 and 13 of murine development, which were identified by high-resolution ultrasound (US) in a previous study.

Results

In the early resorptions detected at day 7, the embryo proper was replaced by maternal haemorrhage and a suppurate focus of maternal neutrophils. In the decidua maternal macrophages transformed to foam cells and formed a second focus of tissue dissolution.

In the late resorptions detected at day 9, the embryo underwent apoptosis without involvement of maternal cells. The apoptotic embryonic cells expressed caspase 3 and embryonic blood cells developed a macrophage like phenotype. Subsequently, the wall of the embryonic vesicle ruptured and the apoptotic embryo was aborted into the uterine lumen. Abortion was initiated by degeneration of the embryonic lacunar trophoblast and dissolution of the maternal decidua capsularis via sterile inflammation and accompanied by maternal haemorrhage, invasion of the apoptotic embryo by maternal neutrophils, and contraction rings of the uterine muscle layers.

Conclusions

We conclude that spontaneous resorption starts with endogenous apoptosis of the embryo without maternal contribution. After break down of the foetal-maternal border, the apoptotic embryo is invaded by maternal neutrophils, aborted into the uterine lumen, and rapidly resorbed. We assume that the innate maternal unspecific inflammation is elicited by disintegrating apoptotic embryonic cells.

Graphical abstract

Hydroxychloroquine may be beneficial in preeclampsia and recurrent miscarriage

Recurrent miscarriage (RM) and vasculoplacental disorders, such as preeclampsia (PE), affect women of childbearing age worldwide. Vascular endothelial dysfunction and immunological impairment are associated with both RM and PE. To date, there is no effective or optimal therapeutic approach for these conditions. Notably, aspirin use is only partially effective in the prevention of PE. Hydroxychloroquine (HCQ) has demonstrated beneficial effects on disease flares, pregnancy outcomes and cardiovascular impairment in systemic erythaematosus lupus (SLE) through its immunomodulatory, vasculoprotective and antithrombotic properties. Here, in the context of the underlying physiological dysregulation associated with PE and RM, the beneficial properties and potential therapeutic efficacy of HCQ are reviewed in anticipation of the results of current and future trials. Two related trials addressing RM in the absence of maternal autoimmune disease are ongoing. Other trials addressing pregnancy outcomes in the presence of maternal autoimmune disease are forthcoming. In this review, we hypothesise that the immunological and endothelial effects of HCQ may be beneficial in the context of PE and RM, regardless of the maternal autoimmune status.

TAFI deficiency causes maladaptive vascular remodeling after hemophilic joint bleeding

Excessive vascular remodeling is characteristic of hemophilic arthropathy (HA) and may contribute to joint bleeding and the progression of HA. Mechanisms for pathological vascular remodeling after hemophilic joint bleeding are unknown. In hemophilia, activation of thrombin-activatable fibrinolysis inhibitor (TAFI) is impaired, which contributes to joint bleeding and may also underlie the aberrant vascular remodeling. Here, hemophilia A (factor VIII-deficient; FVIII-deficient) mice or TAFI-deficient mice with transient (antibody-induced) hemophilia A were used to determine the role of FVIII and TAFI in vascular remodeling after joint bleeding. Excessive vascular remodeling and vessel enlargement persisted in FVIII-deficient and TAFI-deficient mice, but not in transient hemophilia WT mice, after similar joint bleeding. TAFI-overexpression in FVIII-deficient mice prevented abnormal vessel enlargement and vascular leakage. Age-related vascular changes were observed with FVIII or TAFI deficiency and correlated positively with bleeding severity after injury, supporting increased vascularity as a major contributor to joint bleeding. Antibody-mediated inhibition of uPA also prevented abnormal vascular remodeling, suggesting that TAFI's protective effects include inhibition of uPA-mediated plasminogen activation. In conclusion, the functional TAFI deficiency in hemophilia drives maladaptive vascular remodeling in the joints after bleeding. These mechanistic insights allow targeted development of potentially new strategies to normalize vascularity and control rebleeding in HA.

A thrombomodulin-like gene is crucial to the collective migration of epibolic blastomeres during germ layer formation and organogenesis in zebrafish

Background

Thrombomodulin (TM), an integral membrane protein, has long been known for its anticoagulant activity. Recent studies showed that TM displays multifaceted activities, including the involvement in cell adhesion and collective cell migration in vitro. However, whether TM contributes similarly to these biological processes in vivo remains elusive.

Methods

We adapted zebrafish, a prominent animal model for studying molecular/cellular activity, embryonic development, diseases mechanism and drug discovery, to examine how TM functions in modulating cell migration during germ layer formation, a normal and crucial physiological process involving massive cell movement in the very early stages of life. In addition, an in vivo assay was developed to examine the anti-hemostatic activity of TM in zebrafish larva.

Results

We found that zebrafish TM-b, a zebrafish TM-like protein, was expressed mainly in vasculatures and displayed anti-hemostatic activity. Knocking-down TM-b led to malformation of multiple organs, including vessels, heart, blood cells and neural tissues. Delayed epiboly and incoherent movement of yolk syncytial layer were also observed in early TM-b morphants. Whole mount immunostaining revealed the co-localization of TM-b with both actin and microtubules in epibolic blastomeres. Single-cell tracking revealed impeded migration of blastomeres during epiboly in TM-b-deficient embryos.

Conclusion

Our results showed that TM-b is crucial to the collective migration of blastomeres during germ layer formation. The structural and functional compatibility and conservation between zebrafish TM-b and mammalian TM support the properness of using zebrafish as an in vivo platform for studying the biological significance and medical use of TM.

Electronic supplementary material

The online version of this article (10.1186/s12929-019-0549-2) contains supplementary material, which is available to authorized users.

Obstetric and neonatal outcomes in pregnant women treated with high-dose thromboprophylaxis: a retrospective, single-center study

INTRODUCTION

It is well established that women with very high risk of developing antenatal thrombosis benefit from high-dose thromboprophylaxis, however data on outcomes and the safety and efficacy of thromboprophylaxis are scarce. The aim of the study was to evaluate the safety and effectiveness of the Swedish guidelines for high-dose thromboprophylaxis and the obstetric outcomes in a single-center patient cohort.

PATIENTS AND METHODS

Forty-seven women treated at the Department of Obstetrics and Gynecology, Karolinska University Hospital, Solna, Sweden, between 2004 and 2017 were included in this retrospective study. Data on treatment, obstetric, and neonatal outcomes and medical history were collected. Data derived from the Swedish Medical Birth Registry on women giving birth in Stockholm County 2004-2016 were used as controls. The protocol of the study was approved by the Regional Ethics Committee in Stockholm, Sweden.

RESULTS

The initial thromboprophylaxis dose was 5000 IU dalteparin twice daily. No patient developed ablatio placentae or preeclampsia. One patient suffered antenatal muscle vein thrombosis. Six patients (12.7%) suffered postpartum hemorrhage (PPH); however only one patient had severe PPH. Forty-eight children were born. Three children (6%) were diagnosed with intrauterine growth retardation, five (10%) were born small for gestational age and seven (15%) were born premature, the majority of which (except for two premature) to women with thrombophilia.

DISCUSSION

High-dose thromboprophylaxis was effective and safe. The incidence of preeclampsia and ablatio was lower than in controls; however, neonatal outcomes were worse, especially among mothers with thrombophilia. Due to the diversity of the thrombophilic traits, no thrombophilia-specific conclusion could be drawn. Stricter adherence to the guidelines could further decrease the risk for bleeding, whereas more frequent antenatal controls could possible improve neonatal outcomes.

Hydroxychloroquine for prevention of recurrent miscarriage: study protocol for a multicentre randomised placebo-controlled trial BBQ study

INTRODUCTION

Recurrent miscarriage (RM), defined by three or more consecutive losses during the first trimester of pregnancy, affects 1%-2% of fertile couples. Standard investigations fail to reveal any apparent cause in ~50% of couples. However, on the basis of animal models and clinical studies, several hypotheses have been put forward concerning underlying mechanisms of RM: altered ovarian reserve, progesterone defect, thrombotic and/or endothelial dysfunction and immunological disturbances. Nonetheless, no study has yet reached conclusive beneficial clinical evidence for a potential treatment in unexplained RM. Hydroxychloroquine (HCQ) is a molecule with extensive safety data during pregnancy. The pharmacological properties of HCQ (eg, antithrombotic, vascular protective, immunomodulatory, improved glucose tolerance, lipidlowering and anti-infectious) could be effective against some mechanisms of unexplained RM. Furthermore, eventhough clinical benefit of HCQ is suggested in prevention of thrombotic and late obstetric events in antiphospholipid (APL) syndrome, there are no data suggesting the benefit of HCQ in RM in the presence of APL antibodies.

METHODS AND ANALYSIS

Taken all together and given the low cost of HCQ, the aim of this multicentre, randomised, placebo-controlled, double-blind study is to investigate whether HCQ would improve the live birth rate in women with RM, irrespective of maternal thrombophilic status: (1) no known thrombophilia, (2) inherited thrombophilia or (3) APL antibodies. The primary end point is a live and viable birth. After confirming eligibility and obtaining consent, 300 non-pregnant women will be randomised into two parallel groups for a daily oral treatment (HCQ 400 mg or placebo), initiated before conception and stopped at 10 weeks' gestation. If pregnancy does not occur after 1 year, the treatment will be stopped.

ETHICS AND DISSEMINATION

Agreement from the French National Public Health and Drug Security Agency (160765A-22) and ethical approval from the Committee for the Protection of Persons of NORD-OUEST I (2016-001330-97) have been obtained.

TRIAL REGISTRATION NUMBERS

NCT0316513; Pre-results.

Defective TAFI activation in hemophilia A mice is a major contributor to joint bleeding

Joint bleeds are common in congenital hemophilia but rare in acquired hemophilia A (aHA) for reasons unknown. To identify key mechanisms responsible for joint-specific bleeding in congenital hemophilia, bleeding phenotypes after joint injury and tail transection were compared in aHA wild-type (WT) mice (receiving an anti-factor VIII [FVIII] antibody) and congenital HA (FVIII-/-) mice. Both aHA and FVIII-/- mice bled severely after tail transection, but consistent with clinical findings, joint bleeding was notably milder in aHA compared with FVIII-/- mice. Focus was directed to thrombin-activatable fibrinolysis inhibitor (TAFI) to determine its potentially protective effect on joint bleeding in aHA. Joint bleeding in TAFI-/- mice with anti-FVIII antibody was increased, compared with WT aHA mice, and became indistinguishable from joint bleeding in FVIII-/- mice. Measurements of circulating TAFI zymogen consumption after joint injury indicated severely defective TAFI activation in FVIII-/- mice in vivo, consistent with previous in vitro analyses in FVIII-deficient plasma. In contrast, notable TAFI activation was observed in aHA mice, suggesting that TAFI protected aHA joints against bleeding. Pharmacological inhibitors of fibrinolysis revealed that urokinase-type plasminogen activator (uPA)-induced fibrinolysis drove joint bleeding, whereas tissue-type plasminogen activator-mediated fibrinolysis contributed to tail bleeding. These data identify TAFI as an important modifier of hemophilic joint bleeding in aHA by inhibiting uPA-mediated fibrinolysis. Moreover, our data suggest that bleed protection by TAFI was absent in congenital FVIII-/- mice because of severely defective TAFI activation, underscoring the importance of clot protection in addition to clot formation when considering prohemostatic strategies for hemophilic joint bleeding.

THBD sequence variants potentially related to recurrent pregnancy loss

Recurrent pregnancy loss (RPL) is a frequently occurring disease, which is classified as idiopathic in more than 50% of cases. THBD, the endothelial cell receptor for thrombin, has been associated with distinct biological processes and considered a coherent RPL-related candidate gene. In the present study, we have sequenced the complete coding region of THBD in 262 patients affected by RPL. Bioinformatics analysis and screening of controls strongly suggested that the THBD-p.Trp153Gly mutation might be related to RPL aetiology. It could be used, after its validation by functional assays, as a molecular marker for diagnostic/prognostic purposes.

Endosomal NADPH-oxidase is critical for induction of the tissue factor gene in monocytes and endothelial cells

Antiphospholipid antibodies (aPL) have been shown to induce tissue factor (TF) expression in monocytes and endothelial cells. However, the underlying signal transduction has been more or less elusive in the past. We have recently shown that aPL enter the lysosomal route in monocytes and dendritic cells, and subsequently activate endosomal NADPH-oxidase (NOX). The generation of superoxide which is dismutated to hydrogen peroxide upregulates the intracellular toll like receptors (TLR) 7 and 8, and leads to robust production of inflammatory cytokines. Here we show that induction of TF by aPL follows the same signaling pathway. Inhibition of endosomal NOX by the anion channel blocker niflumic acid or capture of superoxide by the radical scavenger N-acetylcysteine blocks TF induction by aPL. Furthermore, monocytes from mice deficient in NOX2 do not increase TF surface expression in response to aPL, while cells from mice deficient in glutathione peroxidase- 1 (GPx-1) show an increased response. Unexpectedly, also induction of TF by tumour necrosis factor (TNF)⍺ and lipopolysaccharide (LPS) was strongly dependent on the activation of endosomal NOX. While TNF⍺ apparently depends almost fully on endosomal NOX, signalling of LPS is only partially dependent on this pathway. These data provide further insight into the well-known role of reactive oxygen species in the induction of TF expression and suggest that endosomal signalling may represent a central coordinating point in this process.

Novel genes and mutations in patients affected by recurrent pregnancy loss

Recurrent pregnancy loss is a frequently occurring human infertility-related disease affecting ~1% of women. It has been estimated that the cause remains unexplained in >50% cases which strongly suggests that genetic factors may contribute towards the phenotype. Concerning its molecular aetiology numerous studies have had limited success in identifying the disease's genetic causes. This might have been due to the fact that hundreds of genes are involved in each physiological step necessary for guaranteeing reproductive success in mammals. In such scenario, next generation sequencing provides a potentially interesting tool for research into recurrent pregnancy loss causative mutations. The present study involved whole-exome sequencing and an innovative bioinformatics analysis, for the first time, in 49 unrelated women affected by recurrent pregnancy loss. We identified 27 coding variants (22 genes) potentially related to the phenotype (41% of patients). The affected genes, which were enriched by potentially deleterious sequence variants, belonged to distinct molecular cascades playing key roles in implantation/pregnancy biology. Using a quantum chemical approach method we established that mutations in MMP-10 and FGA proteins led to substantial energetic modifications suggesting an impact on their functions and/or stability. The next generation sequencing and bioinformatics approaches presented here represent an efficient way to find mutations, having potentially moderate/strong functional effects, associated with recurrent pregnancy loss aetiology. We consider that some of these variants (and genes) represent probable future biomarkers for recurrent pregnancy loss.

Variable phenotypic penetrance of thrombosis in adult mice after tissue-selective and temporally controlled Thbd gene inactivation

Thrombomodulin (Thbd) exerts pleiotropic effects on blood coagulation, fibrinolysis, and complement system activity by facilitating the thrombin-mediated activation of protein C and thrombin-activatable fibrinolysis inhibitor and may have additional thrombin- and protein C (pC)-independent functions. In mice, complete Thbd deficiency causes embryonic death due to defective placental development. In this study, we used tissue-selective and temporally controlled Thbd gene ablation to examine the function of Thbd in adult mice. Selective preservation of Thbd function in the extraembryonic ectoderm and primitive endoderm via the Meox2Cre-transgene enabled normal intrauterine development of Thbd-deficient (Thbd^-/-) mice to term. Half of the Thbd^-/- offspring expired perinatally due to thrombohemorrhagic lesions. Surviving Thbd^-/- animals only rarely developed overt thrombotic lesions, exhibited low-grade compensated consumptive coagulopathy, and yet exhibited marked, sudden-onset mortality. A corresponding pathology was seen in mice in which the Thbd gene was ablated after reaching adulthood. Supplementation of activated PC by transgenic expression of a partially Thbd-independent murine pC zymogen prevented the pathologies of Thbd^-/- mice. However, Thbd^-/- females expressing the PC transgene exhibited pregnancy-induced morbidity and mortality with near-complete penetrance. These findings suggest that Thbd function in nonendothelial embryonic tissues of the placenta and yolk sac affects through as-yet-unknown mechanisms the penetrance and severity of thrombosis after birth and provide novel opportunities to study the role of the natural Thbd-pC pathway in adult mice and during pregnancy.

Placental hemostasis and sterile inflammation: New insights into gestational vascular disease

Activation of the coagulation and inflammatory systems are physiologically occurring during pregnancy. However, excess activation of either system is well documented in gestational vascular diseases (GVD). GVD are placenta-mediated pregnancy complications and a major cause of feto-maternal morbidity and mortality. The causal relevance of excess coagulation and inflammatory responses for GVD remains largely unknown. Deciphering the causal relationship of excess coagulation and inflammation in GVD may allow conceptualizing new therapeutic approaches to combat GVD. Platelet activation and procoagulant extracellular vesicles (EVs) provide a link between coagulation and inflammation and their activation or generation in GVD is well established. As recently shown EVs cause sterile placental inflammation by activating maternal platelets that release ATP and activate purinergic receptor signaling and NLRP3 inflammasome in the embryonic trophoblast. This thrombo-inflammatory mechanism suggests a novel link between coagulation activation and sterile inflammation in GVD. These findings highlight a role of anti-platelet therapies in GVD. In addition, targeting the inflammasome alone or in combination with platelet inhibition may provide a new therapeutic strategy in GVD.

Maternal extracellular vesicles and platelets promote preeclampsia via inflammasome activation in trophoblasts

Preeclampsia (PE) is a placenta-induced inflammatory disease associated with maternal and fetal morbidity and mortality. The mechanisms underlying PE remain enigmatic and delivery of the placenta is the only known remedy. PE is associated with coagulation and platelet activation and increased extracellular vesicle (EV) formation. However, thrombotic occlusion of the placental vascular bed is rarely observed and the mechanistic relevance of EV and platelet activation remains unknown. Here we show that EVs induce a thromboinflammatory response specifically in the placenta. Following EV injection, activated platelets accumulate particularly within the placental vascular bed. EVs cause adenosine triphosphate (ATP) release from platelets and inflammasome activation within trophoblast cells through purinergic signaling. Inflammasome activation in trophoblast cells triggers a PE-like phenotype, characterized by pregnancy failure, elevated blood pressure, increased plasma soluble fms-like tyrosine kinase 1, and renal dysfunction. Intriguingly, genetic inhibition of inflammasome activation specifically in the placenta, pharmacological inhibition of inflammasome or purinergic signaling, or genetic inhibition of maternal platelet activation abolishes the PE-like phenotype. Inflammasome activation in trophoblast cells of women with preeclampsia corroborates the translational relevance of these findings. These results strongly suggest that EVs cause placental sterile inflammation and PE through activation of maternal platelets and purinergic inflammasome activation in trophoblast cells, uncovering a novel thromboinflammatory mechanism at the maternal-embryonic interface.

A combined deficiency of tissue factor and PAR-4 is associated with fatal pulmonary hemorrhage in mice

INTRODUCTION

Mice with a complete absence of tissue factor (TF) die during embryonic development whereas mice with low levels of TF (Low-TF mice) survive to adulthood. Low-TF mice exhibit spontaneous hemorrhage in various organs, including the lung. In contrast, mice can survive without protease-activated receptor (PAR)-4, which is the major thrombin receptor on mouse platelets. We determined the effect of combining a deficiency PAR-4 (primary hemostasis) with a deficiency in TF (secondary hemostasis) on embryonic development and survival of adult mice.

MATERIALS AND METHODS

Low-TF mice (mTF^-/-, hTF^+/+) were crossed with PAR-4^-/- mice to generate heterozygous mice (mTF^+/-, hTF^+/-, PAR-4^+/-). These mice were intercrossed to generate Low-TF mice lacking PAR-4. Mice surviving to wean were genotyped and survival was monitored for 6months.

RESULTS

We observed the expected number of Low-TF,PAR-4^-/- mice at wean indicating survival in utero and after birth. However, an absence of PAR-4 was associated with premature death of all Low-TF,PAR-4^-/- mice in the 6month observational period. This compares with 40% death of the Low-TF,PAR-4^+/+ mice (p=0.003). Low-TF,PAR-4^+/- mice had an intermediate phenotype with 55% of the mice dying within 6months. The primary cause of mortality of Low-TF,PAR-4^-/- mice was pulmonary hemorrhage.

CONCLUSIONS

Low-TF,PAR-4^-/- mice survive into adulthood, but combining a deficiency of primary hemostasis (PAR-4 deficiency) with secondary hemostasis (low levels of TF) leads to premature death primarily due to pulmonary hemorrhage.

Management of inherited thrombophilia in pregnancy

Adverse pregnancy outcomes, such as pregnancy loss and pre-eclampsia, are associated with thrombotic mechanisms and thrombophilia. Antithrombotic interventions, particularly low-molecular-weight heparin, have been investigated in women identified by previous pregnancy outcome; however, the results have been inconsistent. This may reflect heterogeneity of both the study groups and the disease processes resulting in inadequate stratification to guide antithrombotic interventions. Furthermore, the variation in gestation at initiation of low-molecular-weight heparin treatment might be important. Despite limited evidence of efficacy, low-molecular-weight heparin is often used in an attempt to prevent these complications, owing to the lack of other effective treatments and its perceived safety in pregnancy. Research is required to better understand the disease processes, identify possible biomarkers and thereby more homogeneous groups for targeted treatment.

Relationship between Plasma D-Dimer Concentration and Three-Dimensional Ultrasound Placental Volume in Women at Risk for Placental Vascular Diseases: A Monocentric Prospective Study

Introduction

The aim of this study was to correlate placental volumes deduced from three-dimensional ultrasound and virtual organ computer-aided analysis (VOCAL) software with systemic concentrations of D-dimer and soluble endothelial protein C receptor (sEPCR).

Methods

This was a monocentric experimental prospective study conducted from October 2008 to July 2009. Forty consecutive patients at risk of placental vascular pathology (PVP) recurrence or occurrence were included. Placental volumes were systematically measured three times (11–14, 16–18 and 20–22 weeks of gestation (WG)) by two independent sonographers. D-dimers and sEPCR plasma concentrations were measured using ELISA kits (Enzyme Linked ImmunoSorbent Assay).

Results

Eleven patients had a PVP. The plasma D-dimer level was positively correlated with placental volume (r = 0.45, p < 0.001). A smaller placental volume and placental quotient was evidenced in women who developed a PVP at the three gestational ages, and the difference was more pronounced during the third exam (20 WG). No obvious correlation could be demonstrated between the development of a PVP and the levels of D-dimer and sEPCR. There was no significant difference in the values of placental volumes measured by the two sonographers.

Conclusion

The placenta growth could be a major determinant of the elevation of D-dimer during pregnancy. Consideration of placental volume could allow for modulation of the D-dimer concentrations for restoring their clinical interest.

CITED2 modulation of trophoblast cell differentiation: insights from global transcriptome analysis

Trophoblast stem (TS) cells possess the capacity to differentiate along a multi-lineage pathway yielding several specialized cell types. The regulatory network controlling trophoblast cell differentiation is poorly understood. Cbp/p300-interacting transactivator with Glu/Asp-rich carboxy-terminal domain, 2 (CITED2) has been implicated in the regulation of placentation; however, we know little about how CITED2 acts to influence trophoblast cells. Rat Rcho-1 TS cells can be manipulated to proliferate or differentiate into specialized trophoblast lineages and are an excellent model for investigating trophoblast differentiation. CITED2 transcript and protein showed a robust induction during Rcho-1 TS cell differentiation. We used an shRNA knockdown approach to disrupt CITED2 expression in order to investigate its involvement in trophoblast cell differentiation. RNA-sequencing was used to examine the impact of CITED2 on trophoblast cell differentiation. CITED2 disruption affected the differentiating trophoblast cell transcriptome. CITED2 possessed a prominent role in the regulation of cell differentiation with links to several signal transduction pathways and to hypoxia-regulated and coagulation processes. In summary, our findings indicate that CITED2 contributes to the regulation of trophoblast cell differentiation.

FDP-E induces adipocyte inflammation and suppresses insulin-stimulated glucose disposal: effect of inflammation and obesity on fibrinogen Bβ mRNA

Obesity is associated with increased fibrinogen production and fibrin formation, which produces fibrin degradation products (FDP-E and FDP-D). Fibrin and FDPs both contribute to inflammation, which would be expected to suppress glucose uptake and insulin signaling in adipose tissue, yet the effect of FDP-E and FDP-D on adipocyte function and glucose disposal is completely unknown. We tested the effects of FDPs on inflammation in 3T3-L1 adipocytes and primary macrophages and adipocyte glucose uptake in vitro. High-fat-fed mice increased hepatic fibrinogen mRNA expression ninefold over chow-fed mice, with concomitant increases in plasma fibrinogen protein levels. Obese mice also displayed increased fibrinogen content of epididymal fat pads. We treated cultured 3T3-L1 adipocytes and primary macrophages with FDP-E, FDP-D, or fibrinogen degradation products (FgnDP-E). FDP-D and FgnDP-E had no effect on inflammation or glucose uptake. Cytokine mRNA expression in RAW264.7 macrophage-like cells and 3T3-L1 adipocytes treated with FDP-E induced inflammation with maximal effects at 100 nM and 6 h. Insulin-stimulated 2-deoxy-d-[3H]glucose uptake was reduced by 71% in adipocytes treated with FDP-E. FDP-E, but not FDP-D or FgnDP-E, induces inflammation in macrophages and adipocytes and decreases glucose uptake in vitro. FDP-E may contribute toward obesity-associated acute inflammation and glucose intolerance, although its chronic role in obesity remains to be elucidated.

Thrombophilia and Pregnancy Complications

There is a paucity of strong evidence associated with adverse pregnancy outcomes and thrombophilia in pregnancy. These problems include both early (recurrent miscarriage) and late placental vascular-mediated problems (fetal loss, pre-eclampsia, placental abruption and intra-uterine growth restriction). Due to poor quality case-control and cohort study designs, there is often an increase in the relative risk of these complications associated with thrombophilia, particularly recurrent early pregnancy loss, late fetal loss and pre-eclampsia, but the absolute risk remains very small. It appears that low-molecular weight heparin has other benefits on the placental vascular system besides its anticoagulant properties. Its use is in the context of antiphospholipid syndrome and recurrent pregnancy loss and also in women with implantation failure to improve live birth rates. There is currently no role for low-molecular weight heparin to prevent late placental-mediated complications in patients with inherited thrombophilia and this may be due to small patient numbers in the studies involved in summarising the evidence. There is potential for low-molecular weight heparin to improve pregnancy outcomes in women with prior severe vascular complications of pregnancy such as early-onset intra-uterine growth restriction and pre-eclampsia but further high quality randomised controlled trials are required to answer this question.

Thrombomodulin as an intravascular safeguard against inflammatory and thrombotic diseases

INTRODUCTION

Thrombomodulin is a transmembrane protein expressed on the surface of endothelial cells. It plays an important role in regulating inflammation as well as coagulation within blood vessels. Recently, a recombinant form of an extracellular fragment of thrombomodulin (rTM) has been developed and is expected to be useful for patients suffering from inflammatory and thrombotic diseases.

AREAS COVERED

We initially focus on the physiological and biochemical features of thrombomodulin, including its distribution, structure and function. We then discuss potential therapeutic applications of rTM.

EXPERT OPINION

Thrombomodulin exerts anticoagulant and anti-inflammatory effects, in part through activated protein C (APC)-dependent mechanisms. Although recombinant human APC (rhAPC) failed to improve the survival of patients with septic shock and has now been withdrawn from the market, rTM may have some advantages over rhAPC. First, rTM may have less risk of bleeding complications than rhAPC, because rTM needs thrombin to act as an anticoagulant and thus its anticoagulant power can be automatically adjusted by the amount of existing thrombin. Second, the APC-independent actions of rTM might confer benefits, including the suppression of complements, endotoxin (representative pathogen-associated molecular pattern) and high-mobility group box 1 protein (prototypical damage-associated molecular pattern) through the lectin-like domain of rTM.

Characterization of mice harboring a variant of EPCR with impaired ability to bind protein C: novel role of EPCR in hematopoiesis

Mutation of the PC-binding domain of EPCR results in viable mice that exhibit procoagulant and proinflammatory phenotype when challenged. EPCRR84A/R84A mice develop splenomegaly as a result of BM failure, suggesting that EPCR plays an important role in hematopoiesis.

Survival advantage of heterozygous factor V Leiden carriers in murine sepsis

BACKGROUND

The high allelic frequency of the prothrombotic Leiden polymorphism in human blood coagulation factor V (FV) has been speculated to reflect positive selection during evolution. Heterozygous Leiden carriers enrolled in the placebo arm of the PROWESS sepsis trial and heterozygous Leiden mice challenged with endotoxin both showed reduced mortality, whereas homozygous Leiden mice were not protected from lethal endotoxemia. Follow-up analyses of clinical outcomes and of mouse models of infection with various pathogens remained inconclusive.

OBJECTIVE

To establish whether activated protein C resistance of FV Leiden modifies the outcome of bacterial infection in murine sepsis models.

METHODS

Homozygous and heterozygous FV Leiden mice were subjected to gram-positive (S. aureus) or gram-negative (Y. pestis; E. coli) septic peritonitis or polymicrobial, focal septic peritonitis induced by cecal ligation and puncture. The effect of FV Leiden on 7-day survival and bacterial dissemination was assessed. Outcomes were compared with the sepsis survival of mice with genetically impaired hemostasis (hemophilia A, thrombocytopenia, thrombin receptor PAR4 [protease activated receptor 4] deficiency, endothelial protein C receptor [ProcR/EPCR] deficiency).

RESULTS

Heterozygous, but not homozygous, Leiden mice were protected from lethal infection with highly virulent S. aureus and Y. pestis strains. FV Leiden did not affect the outcome of sepsis induced by cecal ligation and puncture, staphylokinase-deficient S. aureus, Pla-deficient Y. pestis, or E. coli. Thrombocytopenia, deficiency of PAR1 or PAR4 did not affect S. aureus sepsis survival, whereas hemophilia A increased mortality. ProcR deficiency selectively abolished the survival advantage of heterozygous Leiden mice.

CONCLUSIONS

In mice, heterozygous FV Leiden carriers are protected from sepsis mortality after infection with clinically relevant human bacterial pathogens.

Activation of Protein C in Human Trophoblasts in Culture and Downregulation of Trophoblast Endothelial Protein C Receptor by TNF-α

In mice, trophoblasts are equipped with a potent anticoagulant mechanism, the protein C pathway. In human placenta, no functional studies of the protein C pathway are available. Human first-trimester trophoblasts (CK(++) HLA-G(+/-) Vim(-)) were isolated and kept in culture for a maximum of 48 hours. Activation of protein C on trophoblasts was at least as efficient as in endothelial cells (4.43 × 10 (-) (7) nmol/L/min/cell). Endothelial protein C receptor (EPCR) was expressed in syncytiotrophoblasts and extravillous trophoblasts. Downregulation of the messenger RNA of trophoblast EPCR occurred when trophoblasts were challenged with tumor necrosis factor α, and it could be prevented by unfractionated heparin but not by low-molecular-weight heparin at therapeutic doses. In conclusion, there is a functional protein C pathway on human first-trimester trophoblasts which can be modulated by inflammation. This finding has implications for the pathogenesis and prevention of placenta-mediated obstetric complications.

Enoxaparin for prevention of unexplained recurrent miscarriage: a multicenter randomized double-blind placebo-controlled trial

It is common practice in many centers to offer antithrombotic medications to women with unexplained recurrent miscarriage, in the presence or absence of inherited thrombophilia. Although no benefit of aspirin vs placebo has been clearly demonstrated, a double-blind placebo-controlled trial on the effect of low-molecular-weight heparin is lacking. We enrolled 258 pregnant women with a history of unexplained recurrent miscarriage (≥2 consecutive miscarriages before 15 weeks' gestation) and a negative thrombophilia workup. They were randomly assigned to receive one daily subcutaneous injection of enoxaparin 40 mg or placebo until 35 weeks' gestation. We included 256 women (mean age 32 years, ≥3 miscarriages: 72%; mean gestational age 39 days of amenorrhea) in the intention-to-treat analysis; 66.6% of 138 who received enoxaparin had a live birth vs 72.9% of 118 who received placebo. The absolute difference was -6% (95% CI, -17.1 to 5.1), excluding a 10% increase in the rate of live-birth on enoxaparin (P = .34). In this first randomized, double-blind, placebo-controlled trial, enoxaparin (40 mg once daily) did not improve the chance of a live birth in nonthrombophilic women with unexplained recurrent miscarriage. This trial is registered at www.ClinicalTrials.gov as #NCT00740545 and the French National Health and Drug Safety Agency (EudraCT #2006-003350-18).