Pravastatin prevents miscarriages in antiphospholipid antibody-treated mice

Immunologic insights in recurrent spontaneous abortion: Molecular mechanisms and therapeutic interventions

Recurrent spontaneous abortion refers to the occurrence of two or more spontaneous abortions before or during the early stages of pregnancy. The immune system plays a crucial role in the maintenance of pregnancy and embryo implantation. Various immune cells, cytokines, and immune regulatory pathways are involved in the complex immune balance required for a stable pregnancy. Studies suggest that immune abnormalities may be associated with some recurrent spontaneous abortion cases, particularly those involving the dysregulation of immune cell function, autoimmune responses, and placental immunity. In terms of treatment, interventions targeting immune mechanisms are crucial. Various therapeutic approaches, including immunomodulatory drugs, immunoadsorption therapies, and immunocellular therapies, are continually being researched and developed. These approaches aim to restore the immune balance, enhance the success rate of pregnancies, and provide more effective treatment options for patients with recurrent spontaneous abortion.

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.

Neutrophils and redox stress in the pathogenesis of autoimmune disease

Polymorphonuclear leukocytes, or neutrophils, are specialist phagocytic cells of the innate immune system. Their primary role is host defence against micro-organisms, which they kill via phagocytosis, followed by release of reactive oxygen species (ROS) and proteolytic enzymes within the phagosome. ROS are generated via the action of the NADPH oxidase (also known as NOX2), in a process termed the 'Respiratory Burst'. This process consumes large amounts of oxygen, which is converted into the highly-reactive superoxide radical O₂^- and H₂O₂. Subsequent activation of myeloperoxidase (MPO) generates secondary oxidants and chloroamines that are highly microbiocidal in nature, which together with proteases such as elastase and gelatinase provide a toxic intra-phagosomal environment able to kill a broad range of micro-organisms. However, under certain circumstances such as during an auto-immune response, neutrophils can be triggered to release ROS and proteases extracellularly causing damage to host tissues, modification of host proteins, lipids and DNA and dysregulation of oxidative homeostasis. This review describes the range of ROS species produced by human neutrophils with a focus on the implications of neutrophil redox products in autoimmune inflammation.

Pravastatin for Preventing and Treating Preeclampsia: A Systematic Review

Importance

We have performed a systematic search to summarize the role of statins for preventing and treating severe preeclampsia.

Objective

The aim of this study was to examine whether pravastatin is a useful and safe alternative for treating preeclampsia during pregnancy.

Evidence Acquisition

A systematic MEDLINE (PubMed) search was performed (1979 to June 2017), which was restricted to articles published in English, using the relevant key words of "statins," "pregnancy," "preeclampsia," "obstetrical antiphospholipid syndrome," and "teratogenicity."

Results

The initial search provided 296 articles. Finally, 146 articles were related to the use of statins during pregnancy, regarding their effect on the fetus and the treatment of preeclampsia. Ten studies were related to in vitro studies, 25 in animals, and 24 in humans (13 case report series and 11 cohort studies). We found 84 studies on reviews of such guidelines on cardiovascular disease (35 studies), use of statins in the antiphospholipid syndrome (25 studies), statin's specific use during pregnancy (13 studies), or preeclampsia treatment (11 studies).

Conclusions

Although the studies are of poor quality, the rate of major congenital abnormalities in the newborn exposed to statins during pregnancy is no higher than the expected when compared with overall risk population. The review shows a potential beneficial role of statins in preventing and treating severe preeclampsia that needs to be evaluated through well-designed clinical trials.

Relevance

This update could influence positively the clinical practice, giving an alternative therapy for clinicians who treat preeclampsia, particularly in severe cases.

10 workshops on Immunology of preeclampsia

For the 10th issue of the « island workshops », now the Reunion Workshops, organised by Pierre Yves Robillard since the first one in Tahiti challenging the "vascular disease only" theory of pre eclampsia and introducing the primipaternity concept, we examined the reasons for considering an Immunological approach to the disease. This (brief) overview thus examines several important topics in an Immunological framework. I have chosen to present here the evolution of the main themes rather than a purely chronological vision.

Emerging Therapies in Antiphospholipid Syndrome

Antiphospholipid syndrome (APS) is a hypercoagulable state characterized by arterial and venous thromboses and pregnancy morbidity in the presence of antiphospholipid antibodies. Although warfarin remains the main therapeutic choice in APS, there is still concern about its efficacy, safety, and patient compliance. Patients with refractory APS to conventional therapy as well as patients with non-classical manifestations of APS may have alternative treatment approaches. APS pathogenesis has been further elucidated over the past years identifying new molecules as potential new treatment targets. This review summarizes available data from in vitro and animal models and clinical studies on the role of new potential treatment approaches including new oral anticoagulants and immunoregulatory agents: direct thrombin or factor Xa inhibitors, hydroxychloroquine, statins, B cell inhibition, complement inhibition, peptide therapy, nuclear factor κB and p38 mitogen-activated kinase inhibitors, defibrotide, abciximab, mTOR inhibitor, and other potential targets. Large multicenter prospective studies of well-characterized APS patients are needed to assess the efficacy and safety profile of these potential treatment alternatives.

Pravastatin to prevent recurrent fetal death in massive perivillous fibrin deposition of the placenta (MPFD)

Massive perivillous fibrin deposition of the placenta (MPFD) or maternal floor infarction (MFI) is a serious condition associated with recurrent complications including fetal death and severe fetal growth restriction. There is no method to evaluate the risk of adverse outcome in subsequent pregnancies, or effective prevention. Recent observations suggest that MFI is characterized by an imbalance in angiogenic/anti-angiogenic factors in early pregnancy; therefore, determination of these biomarkers may identify the patient at risk for recurrence. We report the case of a pregnant woman with a history of four consecutive pregnancy losses, the last of which was affected by MFI. Abnormalities of the anti-angiogenic factor, sVEGFR-1, and soluble endoglin (sEng) were detected early in the index pregnancy, and treatment with pravastatin corrected the abnormalities. Treatment resulted in a live birth infant at 34 weeks of gestation who had normal biometric parameters and developmental milestones at the age of 2. This is the first reported successful use of pravastatin to reverse an angiogenic/anti-angiogenic imbalance and prevent fetal death.

Antiphospholipid Syndrome (APS) - An Update on Clinical Features and Treatment Options

Antiphospholipid syndrome (APS) is an autoantibody disorder characterized by the presence of antiphospholipid (APL) antibodies and heterogeneous clinical manifestations. Patients may present with recurrent thrombosis, obstetric morbidity, cardiac valvular lesions, thrombocytopenia, skin lesions, renal or neurologic abnormalities. We provide a comprehensive review of these diverse clinical features except renal and obstetric complications. Treatment of APS can be challenging as one tries to balance the benefit of anticoagulation therapy in this hypercoagulable state while minimizing the risk of bleeding. We discuss the various therapeutic options including the role of aspirin, warfarin, low molecular weight heparin, new direct thrombin inhibitors, hydroxychloroquine, intravenous gamma globulin, rituximab and others. Lower risk APS patients (i.e. first venous thrombosis) should receive warfarin with a target INR of 2.0-3.0. Higher risk patients (i.e. arterial thrombosis or recurrent venous events) have a target INR of >3.0. Currently, warfarin remains the mainstay in treatment of APS. Because of lack of adequate data, the newer oral direct inhibitors should be considered only when there is a known allergy/ intolerance or poor control with warfarin. Additional vascular and thrombotic risk factors should be aggressively reduced. Further studies involving large number of APS patients, diagnosed according to accepted criteria, are needed to better define the role of newer anticoagulants and other novel therapies.

Targeted therapy in antiphospholipid syndrome

PURPOSE OF REVIEW

To review novel therapeutic targets that are currently under investigation to develop safer, targeted therapies for antiphsopholipid antibody (aPL)-mediated clinical manifestations.

RECENT FINDINGS

Novel therapeutic options potentially available include anti-CD20 monoclonal antibodies and new-generation anticoagulants (such as direct thrombin and anti-Xa inhibitors). Research focusing on interfering with aPL-mediated cell activation, targeting complement components and the innovative concept of blocking the pathogenic subpopulation of aPL with tailored peptides are currently being explored.

SUMMARY

Antiphospholipid syndrome is an autoimmune disease characterized by thrombosis and pregnancy morbidity occurring in patients persistently positive for aPL. Current therapeutic options remain confined to long-term anticoagulation with vitamin K antagonists. The future holds much promise with the identification of novel potential targets, many of which are currently under investigation. The challenge will be to design prospective randomized controlled clinical trials to provide the evidence necessary to support integration of these therapies into clinical practice.

Statins inhibit insulin-like growth factor action in first trimester placenta by altering insulin-like growth factor 1 receptor glycosylation

The rapid rise in obesity, metabolic syndrome and type 2 diabetes is one of the major healthcare problems of the Western world. Affected individuals are often treated with statins (3-hydroxy-3-methylglutaryl co-enzyme A [HMG CoA] reductase inhibitors) to reduce circulating cholesterol levels and the risk of developing cardiovascular disease; given the evolving demographic profile of these conditions, such drugs are increasingly prescribed to women of reproductive age. We have previously shown that exposure of placental tissue to statins inhibits the action of insulin-like growth factors (IGF)-I and -II which are key regulators of trophoblast proliferation and placental development. N-linked glycans in the IGF receptor, IGF1R, influence its presentation at the cell surface. This study aimed to determine whether statins, which are known to affect N-glycosylation, modulate IGF1R function in placenta. Treatment of first trimester villous tissue explants with statins (pravastatin or cerivastatin) or inhibitors of N-glycosylation (tunicamycin, deoxymannojirimycin or castanospermine) altered receptor distribution in trophoblast and attenuated proliferation induced by IGF-I or IGF-II (Ki67; P < 0.05, n = 5). Decreased binding of Phaseolus vulgaris lectin and phytohaemagglutinin to IGF1R immunoprecipitated from treated explants demonstrated reduced levels of complex N-linked glycans. Co-incubation of tissue explants with statins and farnesyl pyrophosphate (which increases the supply of dolichol intermediates), prevented statin-mediated disruption of IGF1R localization and reversed the negative effect on IGF-mediated trophoblast proliferation. These data suggest that statins attenuate IGF actions in the placenta by inhibiting N-linked glycosylation and subsequent expression of mature IGF1R at the placental cell surface.

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.

Pregnancy morbidity in antiphospholipid syndrome: what is the impact of treatment?

Women with persistently circulating antiphospholipid antibodies (aPL) have a higher incidence of recurrent abortions, fetal losses, pre-eclampsia, and placental insufficiency. Current treatment of patients with antiphospholipid syndrome (APS) during pregnancy with heparin and aspirin can act by preventing clot formation and improving live birth rates, but other obstetric morbidities remain high, especially in patients with a history of thrombotic events. In addition to the classical thrombotic placental events, other factors involving inflammation and complement activation seem to play a role in certain complications. In this article, we will review how medications interfere in the pathogenic mechanisms of APS, discuss the impact of current recommended treatment on pregnancy morbidity, and analyze new promising therapies.

Evaluation on potential contributions of protease activated receptors related mediators in allergic inflammation

Protease activated receptors (PARs) have been recognized as a distinctive four-member family of seven transmembrane G protein-coupled receptors (GPCRs) that can be cleaved by certain serine proteases. In recent years, there has been considerable interest in the role of PARs in allergic inflammation, the fundamental pathologic changes of allergy, but the potential roles of PARs in allergy remain obscure. Since many of these proteases are produced and actively involved in the pathologic process of inflammation including exudation of plasma components, inflammatory cell infiltration, and tissue damage and repair, PARs appear to make important contribution to allergy. The aim of the present review is to summarize the expression of PARs in inflammatory and structural cells, the influence of agonists or antagonists of PARs on cell behavior, and the involvement of PARs in allergic disorders, which will help us to better understand the roles of serine proteases and PARs in allergy.

Top 10 clinical research developments in antiphospholipid syndrome

Persistently positive antiphospholipid antibodies (aPL) with thrombosis and/or pregnancy morbidity are a characteristic of antiphospholipid syndrome (APS). Although many challenges and controversies exist regarding APS diagnosis and management, there has been significant progress in APS clinical research in parallel with increased understanding of the pathogenesis. The purpose of this review is to discuss the "top ten" recent clinical developments in APS, including the magnitude of the problem, standardization of aPL tests, predictors of clinical events, diagnostic algorithms, new clinical research collaboration, and potential future treatments, e.g., new anticoagulants and immunosuppressive agents.

Evidence of an imbalance of angiogenic/antiangiogenic factors in massive perivillous fibrin deposition (maternal floor infarction): a placental lesion associated with recurrent miscarriage and fetal death

OBJECTIVE

Massive perivillous fibrin deposition (MPFD) is associated with serious complications of pregnancy including recurrent spontaneous abortion, fetal growth restriction, and fetal demise. The aim of this study was to determine whether maternal plasma concentrations of angiogenic/antiangiogenic factors in MPFD differ from those of uncomplicated pregnancies.

STUDY DESIGN

This retrospective longitudinal case-control study included MPFD cases (n = 10) and control patients (n = 175) with uncomplicated pregnancies who were enrolled in a longitudinal study and delivered at term. Serial plasma concentrations of placental growth factor (PlGF), soluble endoglin (sEng), and soluble vascular endothelial growth factor receptor (sVEGFR)-1 and -2 were determined by an enzyme-linked immunosorbent assay (cases, n = 28 samples; controls, n = 723 samples). Individual analyte concentrations were averaged across gestational age at specimen collection intervals. Linear mixed models were used to test for differences in log-transformed mean analyte concentrations both overall and as a function of time.

RESULTS

The following results were found: (1) patients with MPFD had a lower mean plasma PlGF concentration (P = .03) and higher mean plasma concentrations of sVEGFR-1 and sEng (both P < .01) than controls, adjusted for potential confounders; (2) the mean plasma concentration of PlGF differed further among cases and controls as a function of gestational age interval (P < .0001); however, mean sVEGFR-1 and sEng group differences as a function of gestational age interval approached but did not reach significance (P = .09 and P = .11, respectively); (3) patients with MPFD had lower mean plasma concentrations of PlGF/sVEGFR-1 (P < .0001) and PlGF/sEng (P < .001): both of these relationships differed further as a function of gestational age interval (both P < .0001); and (4) differences in mean sVEGFR-1, sEng, and the ratios of PlGF to sVEGFR-1 and PlGF to sEng were observed before 20 weeks of gestation.

CONCLUSION

An imbalance of angiogenic/antiangiogenic factors is present in patients with MPFD prior to the diagnosis. We propose that these changes participate in the mechanisms responsible for adverse pregnancy outcomes in patients with MPFD.

Complement in pregnancy: a delicate balance

The complement system is a key component of innate host defence that, under normal conditions, is responsible for the opsonization and destruction of potential pathogens. However, inappropriate or excessive activation of complement can have a detrimental effect on the host and has been implicated in the pathophysiology of numerous disease states. Recently, there has been increasing evidence for a role of the complement system and, in particular, the potent pro-inflammatory anaphylatoxin complement component 5a (C5a) in both normal and complicated pregnancy. The following review describes the results of in vitro, animal, and human clinical studies investigating the role of the complement system in healthy pregnancy, recurrent miscarriage, preterm birth, and preeclampsia.

Tissue factor, blood coagulation, and beyond: an overview

Emerging evidence shows a broad spectrum of biological functions of tissue factor (TF). TF classical role in initiating the extrinsic blood coagulation and its direct thrombotic action in close relation to cardiovascular risks have long been established. TF overexpression/hypercoagulability often observed in many clinical conditions certainly expands its role in proinflammation, diabetes, obesity, cardiovascular diseases, angiogenesis, tumor metastasis, wound repairs, embryonic development, cell adhesion/migration, innate immunity, infection, pregnancy loss, and many others. This paper broadly covers seminal observations to discuss TF pathogenic roles in relation to diverse disease development or manifestation. Biochemically, extracellular TF signaling interfaced through protease-activated receptors (PARs) elicits cellular activation and inflammatory responses. TF diverse biological roles are associated with either coagulation-dependent or noncoagulation-mediated actions. Apparently, TF hypercoagulability refuels a coagulation-inflammation-thrombosis circuit in “autocrine” or “paracrine” fashions, which triggers a wide spectrum of pathophysiology. Accordingly, TF suppression, anticoagulation, PAR blockade, or general anti-inflammation offers an array of therapeutical benefits for easing diverse pathological conditions.

Structure, function and pathophysiology of protease activated receptors

Discovered in the 1990s, protease activated receptors(1) (PARs) are membrane-spanning cell surface proteins that belong to the G protein coupled receptor (GPCR) family. A defining feature of these receptors is their irreversible activation by proteases; mainly serine. Proteolytic agonists remove the PAR extracellular amino terminal pro-domain to expose a new amino terminus, or tethered ligand, that binds intramolecularly to induce intracellular signal transduction via a number of molecular pathways that regulate a variety of cellular responses. By these mechanisms PARs function as cell surface sensors of extracellular and cell surface associated proteases, contributing extensively to regulation of homeostasis, as well as to dysfunctional responses required for progression of a number of diseases. This review examines common and distinguishing structural features of PARs, mechanisms of receptor activation, trafficking and signal termination, and discusses the physiological and pathological roles of these receptors and emerging approaches for modulating PAR-mediated signaling in disease.

New therapeutic targets for the antiphospholipid syndrome

IMPORTANCE OF THE FIELD

The antiphospholipid syndrome (APS) is an autoimmune condition whereby pathogenic antiphospholipid antibodies (aPL) cause vascular thrombosis and/or recurrent miscarriage, and carries a high burden of morbidity and mortality. Currently the only proven treatment is long-term anticoagulation, which is not effective in all patients and carries risk of haemorrhage.

AREAS COVERED IN THIS REVIEW

Novel therapeutic targets that are currently being explored for APS in order to address the unmet needs of better, safer and ideally targeted therapy. These include B cell depletion, new-generation anticoagulants, interfering with aPL cell-mediated activation of endothelial cells and platelets both at the cell surface level and intracellularly, targeting components of the complement system and the novel concept of using decoy peptides to target only the pathogenic sub-population of aPL.

WHAT THE READER WILL GAIN

An overview of the potential targets and rationale underpinning them.

TAKE HOME MESSAGE

Though current options remain limited for the treatment of APS, the future holds much promise with the identification of multiple targets, many of which are currently being explored. The challenge will be to undertake carefully designed prospective multi-centre trials to generate the evidence necessary to support integration of such candidates into clinical practice.

Antiphospholipid syndrome treatment beyond anticoagulation: are we there yet?

Persistently positive antiphospholipid antibodies in association with thromboses and/or pregnancy morbidity is the hallmark of the antiphospholipid syndrome. The management of antiphospholipid antibody-positive patients has been focused on utilizing anti-thrombotic medications such as heparin or warfarin. Given that our understanding of the molecular mechanisms of antiphospholipid antibody-mediated thrombosis has been growing, it is highly likely that the current ‘anti-thrombotic’ approach to these patients will be replaced by an ‘immunomodulatory’ approach in the near future. This review article will address the experimental and/or clinical evidence behind some of these potential ‘immunomodulatory’ approaches (tissue factor inhibition, P38 mitogen-activated protein kinase inhibition, nuclear factor-κB inhibition, platelet glycoprotein receptor inhibition, hydroxychloroquine, statins, inhibition of β2GPI and/or anti-β2GPI binding to target cells, complement inhibition, and B cell inhibition) in antiphospholipid syndrome.