Modulation of Trophoblast Angiogenic Factor Secretion by Antiphospholipid Antibodies is Not Reversed by Heparin

Modern Management of Pregnancy in Systemic Lupus Erythematosus: From Prenatal Counseling to Postpartum Support

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease that predominantly affects women of childbearing age. Pregnancy in SLE patients poses unique challenges due to the potential impact on maternal and fetal outcomes. We provide an overview of the management of SLE during pregnancy, including preconception risk stratification and counseling, treatment, and disease activity monitoring. These assessments are critical to minimize maternal and fetal adverse events in pregnant patients with SLE. Disease flares, preeclampsia, antiphospholipid syndrome complications, and maternal mortality are the major risks for a woman with SLE during gestation. Timely treatment of SLE relapse, differentiation of preeclampsia from lupus nephritis, and tailored management for antiphospholipid syndrome are essential for a successful pregnancy. Fetal outcomes include neonatal lupus (NL), preterm birth, cesarean delivery, fetal growth restriction (FGR), and small-for-gestational-age (SGA) infants. We focused on NL, linked to maternal anti-Ro/SS-A and anti-La/SS-B antibodies, which can lead to various manifestations, particularly cardiac abnormalities, in newborns. While there is a common consensus regarding the preventive effect of hydroxychloroquine, the role of echocardiographic monitoring and fluorinated steroid treatment is still debated. Finally, close postpartum monitoring and counseling for subsequent pregnancies are crucial aspects of care.

Antiphospholipid-exposed trophoblast-derived extracellular vesicles express elevated levels of TLR7/8-activating microRNAs and induce endometrial endothelial activation, in part, through TLR7

Women with antiphospholipid syndrome (APS) are at high risk for miscarriage and preeclampsia. Unlike pro-thrombotic systemic APS, obstetric APS is associated with insufficient placentation, as well as inflammation and vascular dysfunction at the maternal-fetal interface. Antiphospholipid antibodies (aPL) can target the placental trophoblast and induce inflammation. We reported that aPL trigger trophoblast cells to produce elevated levels of IL-8 through activation of Toll-like receptor 4 (TLR4). Downstream of TLR4, we found this IL-8 response is mediated by a TLR8-activating microRNA (miR), miR-146a-3p, which is also released by the trophoblast via extracellular vesicles (EVs). Since endothelial dysfunction is a feature of obstetric APS, we sought to determine if other miRs that can activate the RNA sensors, TLR7 and/or TLR8, are released by the trophoblast via EVs after exposure to aPL, and if these EVs can activate human endometrial endothelial cells (HEECs). Using a human first trimester extravillous trophoblast cell line we found that aPL elevated their release of small EVs (<150 nm). These extracellular vesicles released from trophoblast cells exposed to aPL expressed elevated levels of TLR7/8-activating miR-21a and miR-29a, in addition to the previously reported miR-146a-3p. Extracellular vesicles from aPL-exposed human trophoblast cells triggered human endometrial endothelial cells to generate an inflammatory IL-8 response, in part through TLR7. This study highlights EVs as a mode of communication between the placenta and the maternal vasculature, as well as a potential role for TLR7/8-activating miRs in contributing to inflammation at the maternal-fetal interface in obstetric APS.

The pathogenesis of obstetric APS: a 2023 update

The antiphospholipid syndrome (APS) is an autoimmune disease characterized by the persistent presence of antibodies directed against phospholipids and phospholipid-binding proteins that are associated with thrombosis and pregnancy-related morbidity. The latter includes fetal deaths, premature birth and maternal complications. In the early 1990s, a distinct set of autoantibodies, termed collectively antiphospholipid antibodies (aPL), were identified as the causative agents of this disorder. Subsequently histological analyses of the placenta from APS pregnancies revealed various abnormalities, including inflammation at maternal-fetal interface and poor placentation manifested by reduced trophoblast invasion and limited uterine spiral artery remodeling. Further preclinical investigations identified the molecular targets of aPL and the downstream intracellular pathways of key placental cell types. While these discoveries suggest potential therapeutics for this disorder, definitive clinical trials have not been completed. This concise review focuses on the recent developments in the field of basic and translational research pursuing novel mechanisms underlying obstetric APS.

First-trimester serum antiphosphatidylserine antibodies serve as candidate biomarkers for predicting pregnancy-induced hypertension

OBJECTIVE

The aim of this study was to explore whether antiphosphatidylserine (aPS) antibodies play roles in the early prediction of pregnancy-induced hypertension (PIH).

METHODS

The serum levels of different isotypes of aPS antibodies were compared in women diagnosed with PIH (PIH group, n  = 30) and 1 : 1 matched normotensive controls (control group, n  = 30). All patients underwent frozen embryo transfer (FET) cycles, and all serum samples were collected during 11-13 weeks of gestation. Receiver operating characteristic (ROC) curves were drawn to analyze the predictive values of aPS antibodies for PIH.

RESULTS

The women who developed PIH after FET had higher serum optical density values (450 nm) of aPS immunoglobulin (Ig) A (1.31 ± 0.43 vs. 1.02 ± 0.51, P  = 0.022), aPS IgM (1.00 ± 0.34 vs. 0.87 ± 0.18, P  = 0.046), and aPS IgG (0.50 ± 0.12 vs. 0.34 ± 0.07, P  < 0.001) compared with the normotensive controls. The serum concentration of total IgG [48.29 ± 10.71 (g/dl) vs. 34.39 ± 11.62 (g/dl), P  < 0.001] was also higher in the PIH group compared with that in the control group. The aPS IgG alone [area under the curve (AUC): 0.913, 95% confidence interval (CI): 0.842-0.985, P  < 0.001] and the combined analysis of aPS IgA, aPS IgM, aPS IgG, and total IgG (AUC: 0.944, 95% CI: 0.888-1.000, P  < 0.001) had high predictive values for PIH.

CONCLUSION

Serum aPS autoantibody levels during the first trimester of pregnancy are positively associated with the development of PIH. Further validation is needed to clearly identify the distinct contributions and underlying mechanisms for diagnostic applications of aPS autoantibodies in PIH prediction.

Advances in the Pathophysiology of Thrombosis in Antiphospholipid Syndrome: Molecular Mechanisms and Signaling through Lipid Rafts

The pathological features of antiphospholipid syndrome (APS) are related to the activity of circulating antiphospholipid antibodies (aPLs) associated with vascular thrombosis and obstetric complications. Indeed, aPLs are not only disease markers, but also play a determining pathogenetic role in APS and exert their effects through the activation of cells and coagulation factors and inflammatory mediators for the materialization of the thromboinflammatory pathogenetic mechanism. Cellular activation in APS necessarily involves the interaction of aPLs with target receptors on the cell membrane, capable of triggering the signal transduction pathway(s). This interaction occurs at specific microdomains of the cell plasma membrane called lipid rafts. In this review, we focus on the key role of lipid rafts as signaling platforms in the pathogenesis of APS, and propose this pathogenetic step as a strategic target of new therapies in order to improve classical anti-thrombotic approaches with "new" immunomodulatory drugs.

Pathogenesis, Diagnosis and Management of Obstetric Antiphospholipid Syndrome: A Comprehensive Review

Antiphospholipid syndrome is an autoimmune disorder characterized by vascular thrombosis and/or pregnancy morbidity associated with persistent antiphospholipid antibody positivity. Cases fulfilling the Sydney criteria for obstetric morbidity with no previous thrombosis are known as obstetric antiphospholipid syndrome (OAPS). OAPS is the most identified cause of recurrent pregnancy loss and late-pregnancy morbidity related to placental injury. Cases with incomplete clinical or laboratory data are classified as obstetric morbidity APS (OMAPS) and non-criteria OAPS (NC-OAPS), respectively. Inflammatory and thrombotic mechanisms are involved in the pathophysiology of OAPS. Trophoblasts, endothelium, platelets and innate immune cells are key cellular players. Complement activation plays a crucial pathogenic role. Secondary placental thrombosis appears by clot formation in response to tissue factor activation. New risk assessment tools could improve the prediction of obstetric complication recurrences or thromboses. The standard-of-care treatment consists of low-dose aspirin and prophylactic low molecular weight heparin. In refractory cases, the addition of hydroxychloroquine, low-dose prednisone or IVIG improve pregnancy outcomes. Statins and eculizumab are currently being tested for treating selected OAPS women. Finally, we revisited recent insights and concerns about the pathophysiology, diagnosis and management of OAPS.

Antiphospholipid antibody-induced trophoblast responses are differentially modulated by viral dsRNA and viral ssRNA

PROBLEM

Women with antiphospholipid antibodies (aPL) are at increased risk for pregnancy loss and preeclampsia. aPL target the trophoblast and induce a pro-inflammatory, anti-angiogenic and anti-migratory profile. Since infection during pregnancy can increase the risk for preeclampsia, a viral infection could further increase this in women with aPL. The goal of this study was to characterize the effect of viral components on trophoblast responses to aPL.

METHOD OF STUDY

A human first trimester trophoblast cell line was treated with or without aPL or control IgG in the presence of media, viral dsRNA or viral ssRNA. Supernatants were measured for inflammatory IL-1β and IL-8; inflammasome-associated uric acid and caspase-1 activity; and anti-angiogenic sFlt-1. Trophoblast migration was measured using a two-chamber assay.

RESULTS

Viral dsRNA augmented aPL-induced trophoblast caspase-1 activity, and IL-1β and IL-8 secretion in an additive manner. Viral ssRNA inhibited aPL-induced uric acid, IL-1β and sFlt-1 secretion, and further exacerbated aPL-inhibition of trophoblast migration.

CONCLUSION

While viral ssRNA may have some protective effects on aPL-induced inflammation and anti-angiogenic responses, viral dsRNA exacerbated aPL-mediated inflammation and viral ssRNA further limited cell migration, which could prove detrimental to placentation. Thus, viral infections may contribute to adverse pregnancy outcomes in women with aPL.

Platelet-activating factor and antiphospholipid antibodies in recurrent implantation failure

Recurrent implantation failure (RIF) refers to cases in which women have had the failure of the embryo implantation after several in vitro fertilization (IVF). The success rate for IVF depends on many different factors. Implantation is a complex step in a successful pregnancy. Antiphospholipid antibodies (aPLs) and platelet-activating factor (PAF) can be considered as effective factors in the embryo implantation. The first purpose of this study is to compare the levels of aPLs and PAF among RIF and fertile control women. The second purpose is evaluating correlations between the blood levels of these factors in this two groups. The levels of twelve types of aPL and PAF in peripheral blood samples of RIF and fertile control women were checked with ELISA method. The results showed that levels of Anti Cardiolipin antibody IgG was above the normal level in 3% of RIF patients. This study examined for the first time the correlation between twelve types of aPLs and PAF in RIF and fertile women. The results of these correlations show that the serum levels of aPLs affects themselves and the serum levels of PAF. The correlation of aPLs levels and PAF levels was different in the two groups. Differences in the correlations of aPLs levels and PAF levels in two groups show that the equal changes in the level of variables examined can have different effects in RIF and the fertile control groups. It is suggested that the correlation between these variables be evaluated in other studies.

Molecular Mechanisms of "Antiphospholipid Antibodies" and Their Paradoxical Role in the Pathogenesis of "Seronegative APS"

Antiphospholipid Syndrome (APS) is an autoimmune disease characterized by arterial and/or venous thrombosis and/or pregnancy morbidity, associated with circulating antiphospholipid antibodies (aPL). In some cases, patients with a clinical profile indicative of APS (thrombosis, recurrent miscarriages or fetal loss), who are persistently negative for conventional laboratory diagnostic criteria, are classified as "seronegative" APS patients (SN-APS). Several findings suggest that aPL, which target phospholipids and/or phospholipid binding proteins, mainly β-glycoprotein I (β-GPI), may contribute to thrombotic diathesis by interfering with hemostasis. Despite the strong association between aPL and thrombosis, the exact pathogenic mechanisms underlying thrombotic events and pregnancy morbidity in APS have not yet been fully elucidated and multiple mechanisms may be involved. Furthermore, in many SN-APS patients, it is possible to demonstrate the presence of unconventional aPL ("non-criteria" aPL) or to detect aPL with alternative laboratory methods. These findings allowed the scientists to study the pathogenic mechanism of SN-APS. This review is focused on the evidence showing that these antibodies may play a functional role in the signal transduction pathway(s) leading to thrombosis and pregnancy morbidity in SN-APS. A better comprehension of the molecular mechanisms triggered by aPL may drive development of potential therapeutic strategies in APS patients.

Changes of lipoxin levels during pregnancy and the monthly-cycle, condition the normal course of pregnancy or pathology

OBJECTIVE AND DESIGN

The purpose of the review was to gather information on the role and possibilities of using lipoxin in the treatment of infertility and maintaining a normal pregnancy. Ovulation, menstruation, embryo implantation, and childbirth are reactions representing short-term inflammatory events involving lipoxin activities. Lipoxin A4 (LXA4) is an arachidonic acid metabolite, and in cooperation with its positional isomer lipoxin B4 (LXB4), it is a major lipoxin in mammals. Biosynthesis process occurs in two stages: in the first step, the donor cell releases the eicosanoid intermediate; secondarily, the acceptor cell gets and converts the intermediate product into LXA4 (leukocyte/platelet interaction).

RESULTS

Generating lipoxin synthesis may also be triggered by salicylic acid, which acetylates cyclooxygenase-2. Lipoxin A4 and its analogues are considered as specialized pro-resolving mediators. LXA4 is an important component for a proper menstrual cycle, embryo implantation, pregnancy, and delivery. Its level in the luteal phase is high, while in the follicular phase, it decreases, which coincides with an increase in estradiol concentration with which it competes for the receptor. LXA4 inhibits the progression of endometriosis. However, during the peri-implantation period, before pregnancy is confirmed clinically, high levels of LXA4 can contribute to early pregnancy loss and may cause miscarriage. After implantation, insufficient LXA4 levels contribute to incorrect maternal vessel remodeling; decreased, shallow trophoblastic invasion; and the immuno-energetic abnormality of the placenta, which negatively affects fetal growth and the maintenance of pregnancy. Moreover, the level of LXA4 increases in the final stages of pregnancy, allowing vessel remodeling and placental separation.

METHODS

The review evaluates the literature published in the PubMed and Embase database up to 31 December 2019. The passwords were checked on terms: lipoxin and pregnancy with combined endometriosis, menstrual cycle, implantation, pre-eclampsia, fetal growth restriction, and preterm labor.

CONCLUSIONS

Although no human studies have been performed so far, the cell and animal model study results suggest that LXA4 will be used in obstetrics and gynecology soon.

Role of NOD2 in antiphospholipid antibody-induced and bacterial MDP amplification of trophoblast inflammation

Women with antiphospholipid antibodies (aPL) are at high risk for pregnancy complications, such as preeclampsia. We previously demonstrated that aPL recognizing β₂GPI promote an extravillous trophoblast pro-inflammatory, anti-migratory and anti-angiogenic profile similar to that seen in preeclampsia. Since preeclampsia in the absence of aPL may have an underlying infectious element, women with aPL may be at increased risk for preeclampsia or other adverse outcomes if an infection is present. Our objective was to determine the impact the common bacterial component, muramyl dipeptide (MDP), has on trophoblast responses to aPL. Herein, we report that bacterial MDP amplifies trophoblast IL-1β expression, processing, and secretion in the presence of aPL through activation of NOD2. In the absence of MDP, NOD2 also mediates anti- β₂GPI antibody-induced trophoblast IL-1β and VEGF secretion. Additionally, we report a role for extravillous trophoblast vimentin as a novel danger signal that contributes to the aPL-induced trophoblast IL-1β production. Together our data indicate that NOD2 mediates trophoblast inflammatory and angiogenic responses to aPL alone, and mediates trophoblast inflammation in the presence of bacterial MDP. These findings suggest that a bacterial infection at the maternal-fetal interface may exacerbate the impact aPL have on trophoblast inflammation and, thus, on pregnancy outcome.

Modulation of trophoblast function by concurrent hyperglycemia and antiphospholipid antibodies is in part TLR4-dependent

PROBLEM

While diabetes and APS are individually associated with increased risk of poor perinatal outcomes, in particular preeclampsia, recent studies have demonstrated an association between concurrent aPL and diabetes leading to an increased risk of pregnancy morbidity. Hyperglycemia and aPL have independently been shown to alter human trophoblast function by inducing a pro-inflammatory, anti-angiogenic, and antimigratory response. However, little is known about the effects of concurrent hyperglycemia and aPL on trophoblast function.

METHOD OF STUDY

A human first-trimester extravillous trophoblast cell line was exposed to glucose at 5 mmol/L (normoglycemia) or 25 mmol/L (hyperglycemia), all in the presence or absence of low-dose aPL or control IgG. For some experiments, the TLR4 antagonist, LPS-RS, was included. Cell culture supernatants were measured for inflammatory IL-1β and IL-8, and angiogenic PlGF, sFlt-1, and sEndoglin by ELISA. Inflammasome-associated uric acid was measured using a bioassay; caspase-1 was measured using an activity assay. Trophoblast migration was quantified using a two-chamber colorimetric assay.

RESULTS

Compared to excess glucose alone, combination excess glucose and low-dose aPL (a) further augmented trophoblast inflammatory IL-1β, inflammasome-associated uric acid and caspase-1, and pro-angiogenic PlGF; (b) dampened trophoblast inflammatory IL-8, anti-angiogenic sEndoglin, and sFlt-1; and (c) further reduced trophoblast migration.

CONCLUSION

Our findings indicate that while concurrent aPL and hyperglycemia are overall detrimental to trophoblast function, the presence of two simultaneous insults triggers some protective effects.

Obstetric Anti-phospholipid Syndrome: State of the Art

PURPOSE OF REVIEW

This review focuses on new pathogenesis and clinical-therapeutic aspects of obstetric anti-phospholipid syndrome (ob-APS) in the last 5 years.

RECENT FINDINGS

The pathogenesis of ob-APS is multifactorial, including placental infarctions, infiltration of inflammatory cells that cause acute and chronic inflammation, leading to uncontrolled inflammation and poor pregnancy outcomes. A preconception counseling and a patient-tailored treatment are fundamental to improve maternal and fetal outcomes. Thanks to conventional treatment, based on low-dose aspirin and heparin, 70% of women with ob-APS can have successful pregnancies. Women with positive anti-phospholipid antibodies (aPL) without clinical manifestations ("aPL carriers") or with obstetric manifestation not fulfilling ob-APS criteria need to be further investigated in order to assess their best management. Great interest has been given to drugs that could interact in the pathophysiological mechanisms, such as hydroxychloroquine, statins, and eculizumab. These drugs could be considered for patients refractory to conventional therapy.

Antiphospholipid Antibodies Inhibit Trophoblast Toll-Like Receptor and Inflammasome Negative Regulators

OBJECTIVE

Women with antiphospholipid antibodies (aPL) are at risk for pregnancy complications associated with poor placentation and placental inflammation. Although these antibodies are heterogeneous, some anti-β₂ -glycoprotein I (anti-β₂ GPI) antibodies can activate Toll-like receptor 4 (TLR-4) and NLRP3 in human first-trimester trophoblasts. The objective of this study was to determine the role of negative regulators of TLR and inflammasome function in aPL-induced trophoblast inflammation.

METHODS

Human trophoblasts were not treated or were treated with anti-β₂ GPI aPL or control IgG in the presence or absence of the common TAM (TYRO3, AXL, and Mer tyrosine kinase [MERTK]) receptor ligand growth arrest-specific protein 6 (GAS6) or the autophagy-inducer rapamycin. The expression and function of the TAM receptor pathway and autophagy were measured by quantitative reverse transcription-polymerase chain reaction (qRT-PCR), Western blotting, and enzyme-linked immunosorbent assay (ELISA). Antiphospholipid antibody-induced trophoblast inflammation was measured by qRT-PCR, activity assays, and ELISA.

RESULTS

Anti-β₂ GPI aPL inhibited trophoblast TAM receptor function by reducing cellular expression of the receptor tyrosine kinases AXL and MERTK and the ligand GAS6. The addition of GAS6 blocked the effects of aPL on the TLR-4-mediated interleukin-8 (IL-8) response. However, the NLRP3 inflammasome-mediated IL-1β response was not affected by GAS6, suggesting that another regulatory pathway was involved. Indeed, anti-β₂ GPI aPL inhibited basal trophoblast autophagy, and reversing this with rapamycin inhibited aPL-induced inflammasome function and IL-1β secretion.

CONCLUSION

Basal TAM receptor function and autophagy may serve to inhibit trophoblast TLR and inflammasome function, respectively. Impairment of TAM receptor signaling and autophagy by anti-β₂ GPI aPL may allow subsequent TLR and inflammasome activity, leading to a robust inflammatory response.

Antiphospholipid syndrome

Antiphospholipid syndrome (APS) is an autoimmune disease characterized by the presence of antiphospholipid antibodies, such as lupus anticoagulant, anticardiolipin antibodies and anti-β2-glycoprotein 1 antibodies. APS can present with a variety of clinical phenotypes, including thrombosis in the veins, arteries and microvasculature as well as obstetrical complications. The pathophysiological hallmark is thrombosis, but other factors such as complement activation might be important. Prevention of thrombotic manifestations associated with APS includes lifestyle changes and, in individuals at high risk, low-dose aspirin. Prevention and treatment of thrombotic events are dependent mainly on the use of vitamin K antagonists. Immunosuppression and anticomplement therapy have been used anecdotally but have not been adequately tested. Pregnancy morbidity includes unexplained recurrent early miscarriage, fetal death and late obstetrical manifestation such as pre-eclampsia, premature birth or fetal growth restriction associated with placental insufficiency. Current treatment to prevent obstetrical morbidity is based on low-dose aspirin and/or low-molecular-weight heparin and has improved pregnancy outcomes to achieve successful live birth in >70% of pregnancies. Although hydroxychloroquine and pravastatin might further improve pregnancy outcomes, prospective clinical trials are required to confirm these findings.

Low molecular weight heparin and aspirin exacerbate human endometrial endothelial cell responses to antiphospholipid antibodies

PROBLEM

Women with antiphospholipid antibodies (aPL) are at risk for pregnancy complications despite treatment with low molecular weight heparin (LMWH) or aspirin (ASA). aPL recognizing beta2 glycoprotein I can target the uterine endothelium, however, little is known about its response to aPL. This study characterized the effect of aPL on human endometrial endothelial cells (HEECs), and the influence of LMWH and ASA.

METHOD OF STUDY

HEECs were exposed to aPL or control IgG, with or without low-dose LMWH and ASA, alone or in combination. Chemokine and angiogenic factor secretion were measured by ELISA. A tube formation assay was used to measure angiogenesis.

RESULTS

aPL increased HEEC secretion of pro-angiogenic VEGF and PlGF; increased anti-angiogenic sFlt-1; inhibited basal secretion of the chemokines MCP-1, G-CSF, and GRO-α; and impaired angiogenesis. LMWH and ASA, alone and in combination, exacerbated the aPL-induced changes in the HEEC angiogenic factor and chemokine profile. There was no reversal of the aPL inhibition of HEEC angiogenesis by either single or combination therapy.

CONCLUSION

By aPL inhibiting HEEC chemokine secretion and promoting sFlt-1 release, the uterine endothelium may contribute to impaired placentation and vascular transformation. LMWH and ASA may further contribute to endothelium dysfunction in women with obstetric APS.

Do adverse pregnancy outcomes contribute to accelerated cardiovascular events seen in young women with systemic lupus erythematosus?

Cardiovascular events (CVEs) are prevalent in patients with systemic lupus erythematosus (SLE), and it is the young women who are disproportionately at risk. The risk factors for accelerated cardiovascular disease remain unclear, with multiple studies producing conflicting results. In this paper, we aim to address both traditional and SLE-specific risk factors postulated to drive the accelerated vascular disease in this cohort. We also discuss the more recent hypothesis that adverse pregnancy outcomes in the form of maternal-placental syndrome and resultant preterm delivery could potentially contribute to the CVEs seen in young women with SLE who have fewer traditional cardiovascular risk factors. The pathophysiology of how placental-mediated vascular insufficiency and hypoxia (with the secretion of placenta-like growth factor (PlGF) and soluble fms-tyrosine-like kinase-1 (sFlt-1), soluble endoglin (sEng) and other placental factors) work synergistically to damage the vascular endothelium is discussed. Adverse pregnancy outcomes ultimately are a small contributing factor to the complex pathophysiological process of cardiovascular disease in patients with SLE. Future collaborative studies between cardiologists, obstetricians, obstetric physicians and rheumatologists may pave the way for a better understanding of a likely multifactorial aetiological process.

Obstetric antiphospholipid syndrome: early variations of angiogenic factors are associated with adverse outcomes

The prognostic value of angiogenic factors in newly pregnant women with obstetric antiphospholipid syndrome (oAPS) has not been documented. We observed 513 oAPS who experienced three consecutive spontaneous abortions before the 10^th week of gestation or one fetal loss at or beyond the 10^th week. We assessed the plasma concentrations of the proangiogenic factor placenta growth factor (PIGF) and of the antiangiogenic factor soluble fms-like tyrosine kinase-1 on the eve and on the 4^th day of the low-molecular weight heparin-low-dose aspirin treatment. Placenta growth factor and fms-like tyrosine kinase-1 plasma concentrations showed marked increases. Treatment-associated variations of PIGF and of soluble fms-like tyrosine kinase-1 were antagonist risk factors for placenta-mediated complications (PMC) and for severe PMC, for fetal death, stillbirth and neonatal death. The ratio between PIGF increase and soluble fms-like tyrosine kinase-1 was a summary variable whose best cut-off values (1.944.10⁻²) had high negative predictive values for PMC (0.918) and may be used to help rule out the development of PMC in evolutive pregnancies after 19 completed weeks. The early variations of PIGF and soluble fms-like tyrosine kinase-1 concentrations in newly pregnant oAPS may help to detect patients at low risk of PMC. (clinicaltrials.gov identifier: 02855047)

Complement inhibition by hydroxychloroquine prevents placental and fetal brain abnormalities in antiphospholipid syndrome

Placental ischemic disease and adverse pregnancy outcomes are frequently observed in patients with antiphospholipid syndrome (APS). Despite the administration of conventional antithrombotic treatment a significant number of women continue to experience adverse pregnancy outcomes, with uncertain prevention and management. Efforts to develop effective pharmacological strategies for refractory obstetric APS cases will be of significant clinical benefit for both mothers and fetuses. Although the antimalarial drug, hydroxychloroquine (HCQ) is increasingly used to treat pregnant women with APS, little is known about its efficacy and mechanism of action of HCQ. Because complement activation plays a crucial and causative role in placental ischemia and abnormal fetal brain development in APS we hypothesised that HCQ prevents these pregnancy complications through inhibition of complement activation. Using a mouse model of obstetric APS that closely resembles the clinical condition, we found that HCQ prevented fetal death and the placental metabolic changes -measured by proton magnetic resonance spectroscopy in APS-mice. Using 111In labelled antiphospholipid antibodies (aPL) we identified the placenta and the fetal brain as the main organ targets in APS-mice. Using this same method, we found that HCQ does not inhibit aPL binding to tissues as was previously suggested from in vitro studies. While HCQ did not affect aPL binding to fetal brain it prevented fetal brain abnormal cortical development. HCQ prevented complement activation in vivo and in vitro. Complement C5a levels in serum samples from APS patients and APS-mice were lower after treatment with HCQ while the antibodies titres remained unchanged. HCQ prevented not only placental insufficiency but also abnormal fetal brain development in APS. By inhibiting complement activation, HCQ might also be an effective antithrombotic therapy.

β2GP1, Anti-β2GP1 Antibodies and Platelets: Key Players in the Antiphospholipid Syndrome

Anti-beta 2 glycoprotein 1 (anti-β2GP1) antibodies are commonly found in patients with autoimmune diseases such as the antiphospholipid syndrome (APS) and systemic lupus erythematosus (SLE). Their presence is highly associated with increased risk of vascular thrombosis and/or recurrent pregnancy-related complications. Although they are a subtype of anti-phospholipid (APL) antibody, anti-β2GP1 antibodies form complexes with β2GP1 before binding to different receptors associated with anionic phospholipids on structures such as platelets and endothelial cells. β2GP1 consists of five short consensus repeat termed "sushi" domains. It has three interchangeable conformations with a cryptic epitope at domain 1 within the molecule. Anti-β2GP1 antibodies against this cryptic epitope are referred to as 'type A' antibodies, and have been suggested to be more strongly associated with both vascular and obstetric complications. In contrast, 'type B' antibodies, directed against other domains of β2GP1, are more likely to be benign antibodies found in asymptomatic patients and healthy individuals. Although the interactions between anti-β2GP1 antibodies, β2GP1, and platelets have been investigated, the actual targeted metabolic pathway(s) and/or receptor(s) involved remain to be clearly elucidated. This review will discuss the current understanding of the interaction between anti-β2GP1 antibodies and β2GP1, with platelet receptors and associated signalling pathways.

The role of anti-phospholipid antibodies in autoimmune reproductive failure

Anti-phospholipid antibodies (aPL) are autoantibodies that are associated with thrombosis and a range of pregnancy complications including recurrent pregnancy loss and pre-eclampsia. The three clinically relevant, well-characterized aPL are anti-cardiolipin antibodies, lupus anticoagulant and anti-beta-2-glycoprotein I (β2GPI) antibodies. aPL do not bind directly to phospholipids but instead bind to a plasma-binding ‘cofactor’. The most extensively studied cofactor is β2GPI, whose role in pregnancy is not fully elucidated. Although the pathogenicity of aPL in recurrent pregnancy loss is well established in humans and animal models, the association of aPL with infertility does not appear to be causative. aPL may exert their detrimental effects during pregnancy by directly binding trophoblast cells of the placenta, altering trophoblast signalling, proliferation, invasion and secretion of hormones and cytokines, and by increasing apoptosis. Heparin is commonly used to treat pregnant women with aPL; however, as thrombotic events do not occur in the placentae of all women with aPL, it may exert a protective effect by preventing the binding of aPL to β2GPI or by acting through non-thrombotic pathways. The aim of this review is to present evidence summarizing the current understanding of this field.

Antiphospholipid antibodies and the risk of severe and non-severe pre-eclampsia: the NOHA case-control study

BACKGROUND

pre-eclampsia (PEecl) can be defined as non-severe (NS-PEecl) or severe (S-PEecl). Our study aimed to determine the incidence of antiphospholipid antibodies (aPLs) in women with a past history of NS-PEecl or S-PEecl.

PATIENTS AND METHODS

This case-control study includes 195 control women, 199 NS-PEecl patients and 143 S-PEecl patients whose plasma samples were collected 6 months after their first delivery. Each plasma was tested for lupus anticoagulant (LA), anticardiolipin (aCL) and antiβ2GP1 antibodies, as well as antibodies against phosphatidylserine/prothrombin complex (aPS/PT) and domain I of the β2GP1.

RESULTS

When compared with the control group no significant associations were found for the NS-PEecl group after adjustment of confounding variables. For the S-PEecl group, there was an association with antiβ2GP1 immunoglobulin G (IgG) (OR 16.91, 95% CI 3.71-77.06), as well as age, obesity, smoking and multiparity. Antiβ2GP1-domain I IgG was associated with aCL, antiβ2GP1 and aPS/PT IgG in the three groups. aPS/PT IgG was associated with aCL IgG, and aPS/PT IgM was associated with aCL and antiβ2GP1 IgM in the three groups.

CONCLUSION

S-PEecl is a distinct entity from NS-PEecl and is mainly associated with the presence of antiβ2GP1 IgG. Antiβ2GP1 domain I correlates with other aPL IgG tests, and aPS/PT may be promising in patients for whom LA tests cannot be interpreted.

Antiphospholipid antibody-induced miR-146a-3p drives trophoblast interleukin-8 secretion through activation of Toll-like receptor 8

STUDY QUESTION

What is the role of microRNAs (miRs) in antiphospholipid antibody (aPL)-induced trophoblast inflammation?

SUMMARY ANSWER

aPL-induced up-regulation of trophoblast miR-146a-3p is mediated by Toll-like receptor 4 (TLR4), and miR-146a-3p in turn drives the cells to secrete interleukin (IL)-8 by activating the RNA sensor, TLR8.

WHAT IS KNOWN ALREADY

Obstetric antiphospholipid syndrome (APS) is an autoimmune disorder characterized by circulating aPL and an increased risk of pregnancy complications. We previously showed that aPL recognizing beta2 glycoprotein I (β2GPI) elicit human first trimester trophoblast secretion of IL-8 by activating TLR4. Since some miRs control TLR responses, their regulation in trophoblast cells by aPL and functional role in the aPL-mediated inflammatory response was investigated. miRs can be released from cells via exosomes, and therefore, miR exosome expression was also examined. A panel of miRs was selected based on their involvement with TLR signaling: miR-9; miR-146a-5p and its isomiR, miR-146a-3p; miR-155, miR-210; and Let-7c. Since certain miRs can activate the RNA sensor, TLR8, this was also investigated.

STUDY DESIGN, SIZE, DURATION

For in vitro studies, the human first trimester extravillous trophoblast cell line, HTR8 was studied. HTR8 cells transfected to express a TLR8 dominant negative (DN) were also used. Plasma was evaluated from pregnant women who have aPL, either with or without systemic lupus erythematous (SLE) (n = 39); SLE patients without aPL (n = 30); and healthy pregnant controls (n = 20).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Trophoblast HTR8 wildtype and TLR8-DN cells were incubated with or without aPL (mouse anti-human β2GPI mAb) for 48-72 h. HTR8 cells were also treated with or without aPL in the presence and the absence of a TLR4 antagonist (lipopolysaccharide from Rhodobacter sphaeroides; LPS-RS), specific miR inhibitors or specific miR mimics. miR expression levels in trophoblast cells, trophoblast-derived exosomes and exosomes isolated from patient plasma were measured by qPCR. Trophoblast IL-8 secretion was measured by ELISA.

MAIN RESULTS AND THE ROLE OF CHANCE

aPL significantly increased trophoblast cellular and exosome expression of miR-146a-5p, miR-146a-3p, miR-155 and miR-210. aPL-induced up-regulation of trophoblast miR-146a-5p, miR-146a-3p and miR-210, but not miR-155, was inhibited by the TLR4 antagonist, LPS-RS. While inhibition or overexpression of miR-146a-5p had no effect on aPL-induced trophoblast IL-8 secretion, miR-146a-3p inhibition significantly reduced this response. aPL-induced trophoblast IL-8 secretion was inhibited by the presence of the TLR8-DN. In the absence of aPL, transfection of trophoblast cells with a miR-146a-3p mimic significantly increased IL-8 secretion and this was inhibited by the presence of the TLR8-DN. Patients with aPL and adverse pregnancy outcomes (APOs) expressed significantly higher levels of circulating miR-146a-3p compared with healthy pregnant controls with no pregnancy complications (P < 0.05).

LIMITATIONS, REASONS FOR CAUTION

While the enrichment of miR-146a-3p in trophoblast-derived exosomes support the role of this miR acting in a paracrine or endocrine manner through exosome delivery, this has not been demonstrated. However, miR-146a-3p may also exert its pro-inflammatory effect intracellularly within the same trophoblast cell targeted by aPL.

WIDER IMPLICATIONS OF THE FINDINGS

These findings provide a novel mechanism of trophoblast inflammation through miRs activating RNA-sensing receptors. Furthermore, circulating exosomal-associated miR-146a-3p in APS patients may serve clinically as a biomarker for related APOs.

STUDY FUNDING/COMPETING INTERESTS

This study was supported in part by grants from the American Heart Association (#10GRNT3640032 to V.M.A.), the March of Dimes Foundation (Gene Discovery and Translational Research Grant #6-FY12-255 to V.M.A.), NICHD, NIH (R01HD049446 to V.M.A.), the Gina M. Finzi Memorial Student Summer Fellowship from the Lupus Foundation of America (to S.M.G.), and the Yale University School of Medicine Medical Student Fellowship (to S.M.G.). The authors declare no competing financial interests.

TRIAL REGISTRATION NUMBER

N/A.

Human extravillous trophoblasts bind but do not internalize antiphospholipid antibodies

INTRODUCTION

Obstetric morbidity in women with antiphospholipid antibodies (aPLs) may reflect the adverse effects of aPLs on placental cells such as extravillous trophoblasts and the syncytiotrophoblast. Antiphospholipid antibodies may affect the syncytiotrophoblast after being internalised by members of the Low-density lipoprotein receptor (LDLR) family and the antigen of aPLs, β2 glycoprotein I.

AIM

This study aimed to determine whether aPL internalization was a mechanism by which aPLs adversely affect extravillous trophoblasts.

METHOD

of

STUDY

Fluorescently-labelled monoclonal aPLs IIC5 or ID2 were incubated with first trimester extravillous trophoblast outgrowths and visualized by microscopy. The subcellular expression of β2 glycoprotein I and LDLR family members was investigated by live/permeabilised immunocytochemistry.

RESULTS

Unlike the syncytiotrophoblast of anchoring villi, monoclonal aPLs were not internalised by extravillous trophoblasts, which expressed LDLR family members intracellularly. The aPL IIC5 bound to the surface of extravillous trophoblasts in a pattern similar to the extracellular expression of β2 glycoprotein I.

CONCLUSIONS

The mechanisms of action of aPLs are different in extravillous trophoblasts and the syncytiotrophoblast. The interaction of aPLs with the extravillous trophoblast surface, which may involve β2 glycoprotein I, is consistent with reports that aPLs trigger intracellular signaling cascades through cell-surface receptors.

Response to Plasmapheresis Measured by Angiogenic Factors in a Woman with Antiphospholipid Syndrome in Pregnancy

An imbalance of angiogenic and antiangiogenic placental factors such as endoglin and soluble fms-like tyrosine kinase 1 has been implicated in the pathophysiology of preeclampsia. Extraction of these substances by plasmapheresis might be a therapeutical approach in cases of severe early-onset preeclampsia. Case Report. A 21-year-old primigravida with antiphospholipid syndrome developed early-onset preeclampsia at 18 weeks' gestation. She was treated successfully with plasmapheresis in order to prolong pregnancy. Endoglin and sflt-1-levels were measured by ELISA before and after treatment. Endoglin levels decreased significantly after treatment (p < 0.05) and showed a significant decrease throughout pregnancy. A rerise of endoglin and sflt-1 preceded placental abruption 4 weeks before onset of incident. Conclusion. Due to the limited long-term therapeutical possibilities for pregnancies complicated by PE, plasmapheresis seems to be a therapeutical option. This consideration refers especially to pregnancies with early-onset preeclampsia, in which, after first conventional treatment of PE, prolongation of pregnancy should be above all.

Aspirin-triggered lipoxin prevents antiphospholipid antibody effects on human trophoblast migration and endothelial cell interactions

OBJECTIVE

Antiphospholipid antibodies (aPL) interfere with several physiologic functions of human trophoblasts, including reducing their ability to migrate, decreasing their production of angiogenic factors, and inducing an inflammatory response. This may provide the underlying mechanism by which aPL responses lead to recurrent pregnancy loss or preeclampsia in women with obstetric antiphospholipid syndrome (APS). Although treatment with heparin may reduce the rate of recurrent pregnancy loss, the risk of preeclampsia remains high. Therefore, alternative treatments are needed for the management of pregnant patients with APS. Since aspirin-triggered lipoxins (ATLs) have immune and angiogenic modulatory properties, the objective of this study was to determine the effects of the ATL 15-epi-lipoxin A4 on the function of aPL-altered human trophoblasts in the first trimester of pregnancy.

METHODS

A first-trimester human trophoblast cell line (HTR8) was treated with mouse anti-human β2 -glycoprotein I monoclonal antibodies (aPL) in the presence or absence of the ATL 15-epi-lipoxin A4 . Trophoblast migration and interactions with endometrial endothelial cells were measured using Transwell and coculture assays. Trophoblast secretion of cytokines and angiogenic factors was measured by enzyme-linked immunosorbent assay.

RESULTS

Treatment of HTR8 cells with ATL reversed the aPL-induced decrease in trophoblast migration, an effect that appeared to be regulated through restoration of interleukin-6 production. Using a model of spiral artery transformation, aPL and sera from APS patients with pregnancy morbidity disrupted trophoblast-endothelial cell interactions, and treatment with ATL restored the stability of the cocultures. In contrast, ATL treatment did not resolve the proinflammatory and antiangiogenic responses of trophoblasts induced by aPL.

CONCLUSION

These findings indicate that ATLs may have some benefits in terms of preventing the effects of aPL on trophoblast function, which raises the possibility of the use of ATLs as an adjuvant therapy in women with aPL.

Purified IgG from patients with obstetric but not IgG from non-obstetric antiphospholipid syndrome inhibit trophoblast invasion

PROBLEM

Some patients with antiphospholipid syndrome (APS) suffer pregnancy morbidity (PM) but not vascular thrombosis (VT), whilst others suffer VT only. Therefore, we compared the effects of IgG from VT+/PM- and VT-/PM+ subjects on human first-trimester trophoblast (HTR8) cells.

METHOD OF STUDY

HTR-8 cells were incubated with APS VT+/PM-, APS VT-/PM+ or healthy control (HC) IgG. We measured trophoblast invasion by cell invasion assay; mRNA expression of TLR4 and adaptor proteins; phosphorylation of p38 MAPK, NFκB and ERK; and expression of interleukin (IL)-8 and IL-6.

RESULTS

VT-/PM+ IgG, but not VT+/PM- IgG significantly reduced HTR-8 invasion. The effects on invasion were blocked by TLR-4 inhibition. Neither VT+/PM- nor VT-/PM+ IgG altered MyD88 mRNA expression, phosphorylation of signalling molecules or cytokine expression.

CONCLUSIONS

VT-/PM+ IgG exert functionally relevant effects on human trophoblast cells but VT+/PM- IgG do not.

Viral single stranded RNA induces a trophoblast pro-inflammatory and antiviral response in a TLR8-dependent and -independent manner

Interest is growing in the role of viral infections and their association with adverse pregnancy outcomes. The trophoblast is permissive to viruses, but little is known about their impact on the placenta. We previously established that viral single stranded RNA (ssRNA), a Toll-like receptor 8 (TLR8) agonist, induces a restricted trophoblast pro-inflammatory cytokine/chemokine response by upregulating the secretion of interleukin (IL)-6 and IL-8. In parallel, the type I interferon, IFNbeta, is produced and acts back on the cell in an autocrine/paracrine manner to trigger caspase-3-dependent apoptosis. In this study, we sought to extend these findings by determining the mechanisms involved, examining whether viral ssRNA could induce a trophoblast antiviral response, and evaluating the influence of viral ssRNA on pregnancy outcome using a mouse model. Viral ssRNA induced human first-trimester trophoblast inflammation, type I interferon production, an antiviral response, and apoptosis in both a TLR8/MyD88-dependent and -independent manner. Furthermore, administration of viral ssRNA to pregnant mice induced placental caspase-3 activation, a pro-inflammatory cytokine/chemokine, type I interferon, and antiviral response as well as immune cell infiltration. Thus, ssRNA viral infections may compromise pregnancy by altering placental trophoblast survival and function through both TLR8 and non-TLR8 signaling pathways, leading to immune changes at the maternal-fetal interface.

Antiphospholipid antibodies and the placenta: a systematic review of their in vitro effects and modulation by treatment

BACKGROUND

Antiphospholipid antibodies (aPL) are a family of auto-antibodies that are associated with an increased risk of recurrent miscarriage, intrauterine growth restriction and preterm birth. The placenta is a major target of aPL and it is likely that these antibodies promote pregnancy morbidity by affecting trophoblast function. Numerous studies have investigated the effect of aPL on trophoblast function in vitro. However, different trophoblast models and a variety of culture conditions have been employed, resulting in a myriad of different reported findings. This review systematically summarized those published studies that have investigated the effect of aPL on trophoblast function in vitro. In addition, the reported effects of pharmacological treatment on trophoblast function in the presence of aPL were also systematically reviewed.

METHODS

PubMed, Scopus, Embase and Web of Science databases were searched using the keywords 'placenta OR trophoblast' AND 'antiphospholipid antibody OR antiphospholipid syndrome' up to 25 April 2014. Studies were excluded based on the absence of appropriate controls. The effects of aPL on trophoblast proliferation, death, syncytialization, invasion, hormone production, cytokine production, coagulation and complement activation were recorded. The effects of different treatments on the function of trophoblasts in the presence of aPL were also recorded.

RESULTS

A total of 1071 records were retrieved from the four databases. After removing duplicates, the titles and abstracts of 529 articles were reviewed. Of those, 48 articles were read and relevant experimental results were extracted from 47 articles.

CONCLUSIONS

This systematic review provides an overview of all the studies performed to date on the effects of aPL on trophoblast function in vitro. There is considerable support for aPL decreasing trophoblast viability, syncytialization and invasion in vitro. Some work has also suggested that aPL may affect the production of hormones and signalling molecules by trophoblasts, and may stimulate coagulation and complement activation in vitro. Current reports of the in vitro effects of therapeutic treatments on trophoblast function in the presence of aPL are inconclusive. This systematic review has highlighted many gaps in our knowledge of how aPL work and may direct future research in this area.

Antithrombotic treatment for pregnancy complications: which path for the journey to precision medicine?

Haemostatic and vascular biology mechanisms appear to play an important role in the pathogenesis of placenta-mediated pregnancy complications. Although low-dose aspirin (LDA) has a modest effect in preventing preeclampsia, antithrombotic interventions, LDA and low molecular weight heparin (LMWH) have not definitively proven their effectiveness in women with placenta-mediated pregnancy complications selected by previous pregnancy outcome alone. Given the heterogeneous aetiology of placenta-mediated pregnancy complications, it is critical to stratify patients according to maternal and fetal characteristics and disease mechanisms rather than simply by pregnancy outcome, such as miscarriage. Such stratification could identify those who could benefit from antithrombotic interventions in pregnancy. We lack data on genome-wide association studies, biomarkers and trials of interventions applied to specific homogeneous populations. Future studies should focus on elaborating different disease mechanisms and examining antithrombotic interventions in specific and more homogeneous groups, such as thrombophilic women with well-characterized placenta-mediated pregnancy complications, stratified by disease severity and pathological findings. Because of fetal safety concerns with new anticoagulants, the intervention should focus on heparins alone or in combination with LDA. Thus, placenta-mediated pregnancy complications deserve precision medicine, defining disease by mechanism rather than outcome with interventions focused on a more personalized approach.

Effect of hydroxychloroquine on antiphospholipid antibody-induced changes in first trimester trophoblast function

PROBLEM

Women with antiphospholipid syndrome (APS) are at risk for pregnancy complications. Antiphospholipid antibodies (aPL) alter trophoblast function by triggering an inflammatory cytokine response; modulating angiogenic factor secretion; and inhibiting migration. While patients with APS are often treated with hydroxychloroquine (HCQ), its effect on trophoblast function is poorly understood.

METHOD OF STUDY

A human first trimester trophoblast cell line was treated with or without antihuman β2GPI mAbs in the presence or absence of HCQ. Supernatants were analyzed by ELISA. Cell migration was measured using a colormetric assay.

RESULTS

Antiphospholipid antibodies-induced trophoblast IL-8, IL-1 β, PlGF, and sEndoglin secretion were not altered by HCQ. aPL-induced inhibition of trophoblast migration was partially reversed by HCQ, even though HCQ significantly increased secretion of pro-migratory IL-6 to greater than baseline. aPL-induced upregulation of TIMP2 appears to inhibit trophoblast migration; the inability of HCQ to prevent aPL-induced TIMP2 may explain why migration was only partially restored.

CONCLUSION

Hydroxychloroquine reversed the aPL-inhibition of trophoblast IL-6 secretion and partially limited aPL-inhibition of cell migration. Thus, some form of combination therapy that includes HCQ may be beneficial to pregnant APS patients.

Circulating anti-beta2-glycoprotein I antibodies are associated with endothelial dysfunction, inflammation, and high nitrite plasma levels in patients with intermittent claudication

Our aim is to investigate a possible association of circulating anti-beta2-glycoprotein I antibodies (ABGPI) with the endothelial dysfunction, nitric oxide bioactivity dysregulation, and the inflammatory status that surrounds peripheral arterial disease. We carried out an observational translational study, including 50 male patients with intermittent claudication and a healthy control group of 10 male subjects, age and sex matched with the cases. Flow-mediated arterial dilatation (FMAD) was assessed as a surrogate of endothelial dysfunction, and C-reactive protein (hsCRP) was determined as a marker of inflammation. Nitrite plasma levels were measured by colorimetric analysis. Circulating ABGPI titer was detected with indirect immunofluorescence. Titers <1 : 10 represented the reference range and the lower detection limit of the test. Circulating ABGPI titer ≥1 : 10 was detected in 21 (42%) patients and in none of the control subjects (P < 0.01). Patients with ABGPI titer ≥1 : 10 had a lower FMAD (P = 0.01). The CRP levels were higher in patients with ABGPI titer ≥1 : 10 (P = 0.04). The nitrite plasma levels were higher in patients with ABGPI titer ≥1 : 10 (P < 0.01). These data suggest that these circulating ABGPI may collaborate in the development of atherosclerosis; however, further prospective studies are required to establish a causal relationship.

Suppressed soluble Fms-like tyrosine kinase-1 production aggravates atherosclerosis in chronic kidney disease

Patients with chronic kidney disease (CKD) die of cardiovascular diseases for unknown reasons. Blood vessel formation in plaques and its relationship with plaque stability could be involved with signaling through the Flt-1 receptor and its ligands, vascular endothelial growth factor, and the closely related placental growth factor (PlGF). Flt-1 also exists as a circulating regulatory splice variant short-inhibitory form (sFlt-1) that serves as a decoy receptor, thereby inactivating PlGF. Heparin releases sFlt-1 by displacing the sFlt-1 heparin-binding site from heparin sulfate proteoglycans. Heparin could provide diagnostic inference or could also induce an antiangiogenic state. In the present study, postheparin sFlt-1 levels were lower in CKD patients than in control subjects. More importantly, sFlt-1 levels were inversely related to atherosclerosis in CKD patients, and this correlation was more robust after heparin injection, as verified by subsequent cardiovascular events. Knockout of apolipoprotein E (ApoE) and/or sFlt-1 showed that the absence of sFlt-1 worsened atherogenesis in ApoE-deficient mice. Thus, the relationship between atherosclerosis and PlGF signaling, as regulated by sFlt-1, underscores the underappreciated role of heparin in sFlt-1 release. These clinical and experimental data suggest that novel avenues into CKD-dependent atherosclerosis and its detection are warranted.

Anti-β2-glycoprotein I antibodies

Anti-β(2)-glycoprotein I (anti-β(2)GPI) antibodies are the main antiphospholipid antibodies, along with anticardiolipin and lupus anticoagulant, that characterize the autoimmune disease antiphospholipid syndrome (APS). While the exact physiological functions of β(2)GPI are unknown, there is overwhelming evidence that anti-β(2)GPI antibodies are pathogenic, contributing to thrombosis, pregnancy morbidity, and accelerated atherosclerosis in APS and systemic lupus erythematosus patients. The revelation that these antibodies play a central role in the pathogenesis and pathophysiology of APS has driven research to characterize the physiology and structure of β(2)GPI as well as the pathogenic effects of anti-β(2)GPI antibodies. It has also resulted in the development of improved testing methodologies for detecting these antibodies. In this review we discuss the characteristics of β(2)GPI; the generation, pathogenic effects, and standardized testing of anti-β(2)GPI antibodies; and the potential use of therapies that target the β(2)GPI/anti-β(2)GPI interaction in the treatment of APS.

A role for uric acid and the Nalp3 inflammasome in antiphospholipid antibody-induced IL-1β production by human first trimester trophoblast

Women with antiphospholipid syndrome (APS) are at risk of recurrent pregnancy loss and obstetrical disorders, such as preeclampsia and intrauterine growth restriction (IUGR). Antiphospholipid antibodies (aPL) directly target the placenta by binding beta₂-glycoprotein I (β₂GPI) expressed on the trophoblast. We recently demonstrated in human first trimester trophoblast cells that anti-β₂GPI antibodies (Abs) induce the secretion of IL-1β in a Toll-like receptor 4 (TLR4)-dependent manner. IL-1β secretion requires processing of pro-IL-1β and this is mediated by the inflammasome, a complex of Nalp3, apoptosis-associated speck-like protein containing a CARD (ASC) and caspase-1. The objective of this study was to determine if aPL induce IL-1β production in trophoblast via the inflammasome. Using a human first trimester trophoblast cell line, we demonstrated that a mouse anti-β₂GPI mAb and human polyclonal aPL-IgG induce IL-1β processing and secretion, which was partially blocked upon caspase-1 inhibition. Nalp3 and ASC knockdown also attenuated anti-β₂GPI Ab-induced IL-1β secretion. Furthermore, aPL stimulated the production of uric acid in a TLR4-dependent manner; and inhibition of uric acid prevented aPL-induced IL-1β production by the trophoblast. These findings demonstrate that aPL, via TLR4 activation, induce a uric acid response in human trophoblast, which in turn activates the Nalp3/ASC inflammasome leading to IL-1β processing and secretion. This novel mechanism may account for the inflammation at the maternal-fetal interface, which causes placental dysfunction and increases the risk of adverse pregnancy outcome in patients with APS.

Management of women with recurrent pregnancy losses and antiphospholipid antibody syndrome

Antiphospholipid antibodies (aPL) have been associated with recurrent pregnancy losses (RPL) and other obstetrical complications. The diagnostic criteria for the classical antiphospholipid antibody syndrome (APS) have been utilized for the detection of obstetrical APS in women with RPL. However, laboratory findings and immunopathology of obstetrical APS are significantly different from those of classical APS. In addition, many women with RPL who have positive aPL do not have symptoms consistent with the current APS criteria. The induction of a proinflammatory immune response from trophoblasts and complement activation by aPL rather than thromboembolic changes has been reported as a major immunopathological feature of obstetrical APS. Heparin treatment has been reported to be effective in prevention of early pregnancy loss with APS but not for the late pregnancy loss or complications. The complex effects of heparin may explain the limited efficacy of heparin treatment in RPL. New diagnostic criteria for obstetrical APS are needed urgently, and new therapeutic approaches should be explored further.

Perinatal and early postnatal factors underlying developmental delay and disabilities

A delay in meeting developmental milestones may be secondary to perinatal events, involving complicated interactions between mother and fetus during delivery. Maternal factors including weight, diet, and morbidities can affect neonatal adaptation and later development. Prematurity, low birth weight, and previous intrauterine insults as well as complications during delivery of a previously normal fetus increase the risk for perinatal stress. In this article, the literature on perinatal and early postnatal factors that underlie risks for developmental delay and disabilities is reviewed. Studies that concern neuroprotective therapies and prediction of long-term neurologic outcome by clinical examination, neuroimaging techniques, and electroencephalographic studies are reviewed as well.

Nod1, but not the ASC inflammasome, contributes to induction of IL-1β secretion in human trophoblasts after sensing of Chlamydia trachomatis

Chlamydia trachomatis (Ct) is an obligate intracellular bacterial pathogen. Previously, we showed that infection of human trophoblast cells by Ct triggers the secretion of the pro-inflammatory cytokine, interleukin (IL)-1β. The aim of this study was to understand the innate immune pathways involved in trophoblast production of IL-1β after Ct infection. The approach we took was to inhibit the expression or function of the key Toll-like receptors (TLRs), Nod-like receptors, and inflammasome components that have been associated with chlamydia infection. In this study, we report that Ct-induced trophoblast IL-1β secretion is associated with the transcription of IL-1β mRNA, the translation and processing of pro-IL-1β, and the activation of caspase-1. In addition, we demonstrate that Ct-induced IL-1β production and secretion by the trophoblast is independent of TLR2, TLR4, MyD88, and the Nalp3/ASC inflammasome. Instead we report, for the first time, the importance of Nod1 for mediating trophoblast IL-1β secretion in response to a Ct infection.

Novel transcriptional regulation of VEGF in inflammatory processes

Vascular endothelial growth factor (VEGF) is a critical angiogenic factor affecting endothelial cells, inflammatory cells and neuronal cells. In addition to its well-defined positive role in wound healing, pathological roles for VEGF have been described in cancer and inflammatory diseases (i.e. atherosclerosis, rheumatoid arthritis, inflammatory bowel disease and osteoarthritis). Recently, we showed that transcription factors LITAF and STAT6B affected the inflammatory response. This study builds upon our previous results in testing the role of mouse LITAF and STAT6B in the regulation of VEGF-mediated processes. Cells cotransfected with a series of VEGF promoter deletions along with truncated forms of mLITAF and/or mSTAT6B identified a DNA binding site (between −338 and −305 upstream of the transcription site) important in LITAF and/or STAT6B-mediated transcriptional regulation of VEGF. LITAF and STAT6B corresponding protein sites were identified. In addition, siRNA-mediated knockdown of mLITAF and/or mSTAT6B leads to significant reduction in VEGF mRNA levels and inhibits LPS-induced VEGF secretion in mouse RAW 264.7 cells. Furthermore, VEGF treatment of mouse macrophage or endothelial cells induces LITAF/STAT6B nuclear translocation and cell migration. To translate these observations in vivo, VEGF164-soaked matrigel were implanted in whole-body LITAF-deficient animals (TamLITAF^−/−), wild-type mice silenced for STAT6B, and in respective control animals. Vessel formation was found significantly reduced in TamLITAF^−/− as well as in STAT6B-silenced wild-type animals compared with control animals. The present data demonstrate that VEGF regulation by LITAF and/or STAT6B is important in angiogenesis signalling pathways and may be a useful target in the treatment of VEGF diseases.

The effect of hereditary versus acquired thrombophilia on triple test Down's syndrome screening

OBJECTIVE

To compare the profile of mid gestation triple test serum markers between a cohort of women with history of pregnancy complications with hereditary versus acquired thrombophilia. All were treated with low molecular weight heparin (LMWH) prior to 12 weeks' gestation.

METHODS

A retrospective analysis of second trimester maternal serum screening results for Down syndrome was performed comparing women with inherited versus acquired thrombophilia, all treated with LMWH. The test results were calculated from the combination of triple serum markers and maternal age, and expressed as a multiple of the gestation normal medians (MoM). Results in the study groups were compared with MoM values calculated from our local population (controls).

RESULTS

The median human chorionic gonadotropin (hCG) level was higher only in the acquired thrombophilia group (N = 47) as compared with the control group (1.3 vs. 0.99 MoM, P = 0.005), and not different between the hereditary thrombophilia group (N = 60) (1.1 MoM) and the control group. Alpha-fetoprotein and unconjugated estriol MoMs did not differ between women with inherited (0.95, 0.97), acquired thrombophilia (0.99, 0.90), and controls (1.01, 0.98), respectively.

CONCLUSION

In the interpretation of second trimester maternal serum screening, consideration should be given to the higher hCG maternal serum levels that may occur in women with acquired thrombophilia, even those treated early in pregnancy with LMWH. The higher hCG serum levels may signal the possibility of placental dysfunction, rather than fetal aneuploidy.

[Antiphospholipid syndrome and pregnancy]

Antiphospholipid syndrome is characterized by arterial and venous thromboembolic events and persistent laboratory evidence of antiphospholipid antibodies. Obstetric complications such as recurrent miscarriage, early delivery, oligohydramnios, prematurity, intrauterine growth restriction, fetal distress, fetal or neonatal thrombosis, pre-eclampsia/eclampsia, and HELLP syndrome are also hallmarks of antiphospholipid syndrome. This syndrome is one of the diseases associated with the most severe thrombotic risk. Changes in the hemostatic system during normal pregnancy also result in a hypercoagulable state resulting in elevated thrombotic risk. Thromboembolic events are responsible of the vast majority of maternal and fetal deaths. Administration of appropriate thromboprophylaxis helps prevent thromboembolic complications during pregnancy in women with antiphospholipid syndrome and also give birth to healthy children. It is important to centralize the medication and management of these patients. It helps in the thoughtful care of these pregnant women encountering serious problems.

Distinct effects of unfractionated heparin versus bivalirudin on circulating angiogenic peptides

Background

Human studies of therapeutic angiogenesis, stem-cell, and progenitor-cell therapy have failed to demonstrate consistent clinical benefit. Recent studies have shown that heparin increases circulating levels of anti-angiogenic peptides. Given the widely prevalent use of heparin in percutaneous and surgical procedures including those performed as part of studies examining the benefit of therapeutic angiogenesis and cell-based therapy, we compared the effects of unfractionated heparin (UFH) on angiogenic peptides with those of bivalirudin, a relatively newer anticoagulant whose effects on angiogenic peptides have not been studied.

Methodology/Principal Findings

We measured soluble fms-like tyrosine kinase-1 (sFLT1), placental growth factor (PlGF), vascular endothelial growth factor (VEGF), and soluble Endoglin (sEng) serum levels by enzyme linked immunosorbent assays (ELISA) in 16 patients undergoing elective percutaneous coronary intervention. Compared to baseline values, sFLT1 and PlGF levels increased by 2629±313% and 253±54%, respectively, within 30 minutes of UFH therapy (p<0.01 for both; n = 8). VEGF levels decreased by 93.2±5% in patients treated with UFH (p<0.01 versus baseline). No change in sEng levels were observed after UFH therapy. No changes in sFLT1, PlGF, VEGF, or sEng levels were observed in any patients receiving bivalirudin (n = 8). To further explore the direct effect of anticoagulation on circulating angiogenic peptides, adult, male wild-type mice received venous injections of clinically dosed UFH or bivalirudin. Compared to saline controls, sFLT1 and PlGF levels increased by >500% (p<0.01, for both) and VEGF levels increased by 221±101% (p<0.05) 30 minutes after UFH treatment. Bivalirudin had no effect on peptide levels. To study the cellular origin of peptides after anticoagulant therapy, human coronary endothelial cells were treated with UFH and demonstrated increased sFLT1 and PlGF levels (ANOVA p<0.01 for both) with reduced VEGF levels (ANOVA p<0.05). Bivalirudin had no effect on peptide levels in vitro.

Conclusions/Significance

Circulating levels of sFLT1, PlGF, and VEGF are significantly altered by UFH, while bivalirudin therapy has no effect. These findings may have significant implications for clinical studies of therapeutic angiogenesis, stem-cell and progenitor-cell therapy.