Antiphospholipid antibodies affect trophoblast gonadotropin secretion and invasiveness by binding directly and through adhered beta2-glycoprotein I

Antiphospholipid antibody-mediated reproductive failure in antiphospholipid syndrome

The association of elevated titers of circulating antiphospholipid (anti-PL) Abs in antiphospholipid syndrome (APS) and reproductive failure is well established in the literature. The clinical features include recurrent abortions at various stages, including implantation, placentation in the first trimester, miscarriages in the second and third trimesters, intrauterine growth retardation, preeclampsia with placental insufficiency and growth restrictions, arterial and venous thrombosis, and possibly also infertility. APS-mediated recurrent pregnancy loss and other features of reproductive failure might result from diverse autoimmune factors, inflammation, involving different mechanisms, which encompass pathogenic anti-PL Abs. Herein, we discuss the association of anti-PL Abs with reproductive failure with special emphasis on antiphospholipid autoantibodies characterizing APS. This association is evident from either human studies or murine models.

Decreased expression of heparin-binding epidermal growth factor-like growth factor as a newly identified pathogenic mechanism of antiphospholipid-mediated defective placentation

OBJECTIVE

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) plays a role in blastocyst implantation and is down-regulated in preeclampsia and in hypertensive pregnancy disorders associated with defective extravillous trophoblast invasion. Defective placentation and severe preeclampsia are also features of the antiphospholipid syndrome (APS). The purpose of this study was to investigate whether abnormal HB-EGF expression plays a pathogenic role in antiphospholipid antibody (aPL)-mediated defective placentation.

METHODS

HB-EGF expression in placental tissue was evaluated by Western blotting and messenger RNA analysis in normal and APS placentae. Polyclonal IgG fractions or monoclonal beta(2)-glycoprotein I-dependent aPL and their respective controls were investigated for the following 4 features: their binding to human trophoblast monolayers, as determined by cell enzyme-linked immunosorbent assay (ELISA); their effect on HB-EGF expression by Western blotting in trophoblast cell extracts as well as by ELISA as a protein secreted in the culture supernatants; their inhibitory effect on in vitro trophoblast invasiveness, as evaluated by Matrigel assay; and their inhibitory effect on matrix metalloproteinase (MMP) levels, as measured by gelatin zymography. Experiments were also performed in the presence of serial concentrations of heparin or recombinant HB-EGF.

RESULTS

Placental APS tissue displayed reduced expression of HB-EGF. Polyclonal and monoclonal aPL bound to trophoblast monolayers and significantly reduced the in vitro synthesis and secretion of HB-EGF. Heparin inhibited aPL binding and restored HB-EGF expression in a dose-dependent manner. Addition of recombinant HB-EGF reduced the in vitro aPL-induced inhibition of Matrigel invasiveness as well as MMP-2 levels.

CONCLUSION

These preliminary findings suggest that the reduction of aPL-mediated HB-EGF represents an additional mechanism that is responsible for the defective placentation associated with APS and that heparin protects from aPL-induced damage by inhibiting antibody binding.

Neurodevelopment in the offspring of Japanese systemic lupus erythematosus patients

OBJECTIVE

To evaluate pregnancy outcome of systemic lupus erythematosus (SLE) and the neuropsychological outcomes in offspring of SLE mothers.

STUDY DESIGN

Pregnancy outcomes of SLE patients from 1989 to 2006 were determined and the neuropsychological development of the children born to SLE patients was examined suited for their age; Bayley Scales of Infant Development up to four years and Kauffmann Assessment Battery for Children from four years onwards.

RESULTS

Of the 233 deliveries, 58 (24.7%) were preterm, 72 (30.9%) were low-birth-weight, and 46 (19.7%) were IUGR. Twenty-six children enrolled in this study had normal intelligence. The mean MDI and PDI were 95.8+/-10.1 and 94.6+/-14.1, respectively. The mean scores for the Sequential Processing scale, Simultaneous Processing scale, and Mental Processing composite were 103.1+/-13.3, 104.2+/-10.2, and 104.2+/-12.2, respectively. In the children with anti-Ro/SS-A antibody-positive mothers, mean gestational age and birth weight were significantly lower (p<0.05), as a result, the mean score of Sequential Processing and Mental Processing were significantly lower than that of negative mothers. The presence of maternal antiphospholipid antibody was not related to gestational age, birth weight and any score on the intelligence tests, except for the rate of IUGR.

CONCLUSION

The rates of preterm delivery and IUGR were frequent in the SLE patients and careful monitoring and management of the disease during pregnancy are still necessary. We should examine the neurodevelopment of the children born from mothers with anti-Ro/SS-A antibody prospectively.

Antiphospholipid antibodies limit trophoblast migration by reducing IL-6 production and STAT3 activity

PROBLEM

Women with antiphospholipid antibodies (aPL) are at risk of recurrent miscarriage and pre-eclampsia. aPL target the placenta by binding to beta(2)-glycoprotein I (beta(2) GPI) expressed by the trophoblast. The objective of this study was to evaluate if and how aPL affect first trimester trophoblast migration.

METHOD OF STUDY

First trimester trophoblast cells were treated with anti-beta(2) GPI monoclonal antibodies. Migration was determined using a two-chamber assay. Interleukin (IL)-6 production was evaluated by RT-PCR and enzyme-linked immunosorbent assay, and signal transducer and activator of transcription 3 (STAT3) activation was assessed by western blot.

RESULTS

Trophoblast cells constitutively secreted IL-6 in a time-dependent manner and this directly correlated with STAT3 phosphorylation. In the presence of anti-beta(2) GPI Abs, trophoblast IL-6 mRNA levels and secretion was downregulated in a Toll-like receptor 4/MyD88-independent manner and this correlated with a reduction in phosphorylated STAT3 levels. In addition, the anti-beta(2) GPI Abs reduced the migratory potential of trophoblast. Heparin was able to reverse aPL-dependent inhibition of trophoblast IL-6 secretion and migration.

CONCLUSION

This study demonstrates that aPL limit trophoblast cell migration by downregulating trophoblast IL-6 secretion and STAT3 activity. As heparin was unable to prevent these effects, our findings may explain why women with antiphospholipid syndrome, treated with heparin, remain at risk of developing obstetrical syndromes, associated with impaired deep placentation, such as pre-eclampsia.

Antiphospholipid and Anti‐DNA Antibodies Are Not Associated with the Elevated Release of Circulatory Fetal DNA in Pregnancies Affected by Preeclampsia

OBJECTIVES

We have previously shown that the levels of circulatory fetal DNA are elevated in preeclampsia and that these increases correspond to disease severity. Several reports have indicated that increased levels of antiphospholipid (anti-PL) and anti-DNA antibodies may be associated with preeclampsia, in particular with the severe forms of the disorder. Since the release of cell-free DNA by the placenta is attributed to some form of cell death or damage and as anti-PL and anti-double-stranded DNA (dsDNA) antibodies have been proposed to lead to placental damage, we have studied the relationship between these parameters in preeclampsia.

METHODS

Circulating fetal DNA levels in samples taken from pregnant women with mild (n = 12) or severe (n = 12) preeclampsia and from normal pregnant controls (n = 35) were quantified using a Taqman real-time Polymerase Chain Reaction (PCR) assay. The Anti-PL antibodies (IgG and IgM) were assayed by anticardiolipin ELISA and by commercial anti-beta2-Glycoprotein I (GPI) ELISA kits. Anti-dsDNA antibodies (IgG and IgM) were analyzed by a commercially available anti-dsDNA ELISA kit.

RESULTS

No correlation could be drawn with the quantity of circulatory fetal DNA in the samples analyzed and corresponding anti-PL or anti-dsDNA antibody levels. Furthermore, no significant difference existed between the levels of these antibodies in the two study groups and the control cohort.

CONCLUSION

Our data suggest that the mechanism leading to the increased release of cell-free circulatory DNA from the placenta does not involve trophoblast damage mediated by these agents. Our analysis also questions the reported involvement of anti-PL and anti-DNA antibodies in preeclampsia.

Mechanisms of antiphospholipid antibody-associated pregnancy complications

Women with antiphospholipid syndrome (APS) and antiphospholipid antibodies (aPL) are at high risk for recurrent spontaneous miscarriage and late pregnancy complications, such as preeclampsia and preterm labor. Recent clinical and experimental observations suggest that the pathophysiology of pregnancy failure in patients with APS may involve inflammation at the maternal-fetal interface and disruption of normal trophoblast function and survival, rather than a pro-thrombotic event. While treatment with heparin and aspirin from early pregnancy has been shown to significantly increase the live birth rate in recurrent miscarriage patients with APS, the incidence of severe late pregnancy complications still remains high. This review will discuss what is currently known about the mechanisms by which aPL may compromise pregnancy outcome.

Antiphospholipid antibodies induce a pro-inflammatory response in first trimester trophoblast via the TLR4/MyD88 pathway

PROBLEM

Women with antiphospholipid antibodies (aPL) are at risk for recurrent miscarriage, pre-eclampsia, and pre-term labor. aPL target the placenta directly by binding to beta(2)-glycoprotein I (beta(2)GPI) expressed on the surface of trophoblast cells. The objective of this study was to determine the effects of aPL on trophoblast function and the mechanisms involved.

METHOD OF STUDY

First trimester trophoblast cells were treated with anti-beta(2)GPI monoclonal antibodies and patient-derived aPL, after which cell survival and function was evaluated.

RESULTS

We report that anti-beta(2)GPI antibodies trigger an inflammatory response in trophoblast, characterized by increased secretion of interleukin (IL)-8, MCP-1, GRO-alpha, and IL-1beta, and that this occurs in a TLR-4/MyD88-dependent manner. At high concentrations, these antibodies also induce caspase-mediated cell death. This was attenuated upon disabling of the MyD88 pathway, suggesting that anti-beta(2)GPI-induced inflammatory mediators compromise trophoblast survival by acting in an autocrine/paracrine manner. Enhanced IL-8, GRO-alpha, and IL-1beta secretion also occurred when trophoblast cells were incubated with antibodies from patients with antiphospholipid syndrome. Heparin, which acts as a pro-survival factor in human trophoblast, attenuated the anti-beta(2)GPI antibody-mediated cell death, and also the pro-inflammatory response, but only at high concentrations.

CONCLUSION

These findings demonstrate that aPL triggers a placental inflammatory response via the TLR-4/MyD88 pathway, which in turn compromises trophoblast survival. Thus, the TLR-4/MyD88 pathway may provide a new therapeutic target to improve pregnancy outcome in antiphospholipid syndrome patients.

Neonatal and pregnancy outcome in primary antiphospholipid syndrome: a 10-year experience in one medical center

BACKGROUND

Antiphospholipid syndrome (APS) in pregnancy is characterized by the presence of maternal autoantibodies in association with recurrent fetal loss and severe obstetric complications such as prematurity, intrauterine growth retardation, or placental insufficiency. This study aimed to assess the perinatal outcomes in neonates born to mothers with APS.

METHODS

The medical records of pregnant women with APS and their offspring were retrospectively collected between January 1997 and July 2007. Maternal and perinatal histories including demographic data, medications, obstetric histories, and neonatal clinical manifestations and laboratory data were analyzed.

RESULTS

Eleven women with a diagnosis of primary APS were included. Eight of these patients had experienced frequent spontaneous abortions (72.7%), and four had unexplained fetal deaths (36.3%). None of them had vascular thrombosis. Specific autoimmune antibodies were detected, including anticardiolipin antibody (n=6), anti-beta2 glycoprotein I (n=3), and antiphospholipid antibody (n=7). Among the pregnancies, five had preterm births (45.4%), two had intrauterine growth retardation (18.1%), and one had intrauterine fetal demise (9.1%). Thrombocytopenia was noted in three babies, all of whose mothers had lower platelet counts. One patient with neonatal thrombocytopenia developed intracranial hemorrhage, seen on brain images.

CONCLUSIONS

This limited study suggests that neonates born to mothers with primary APS are at risk of prematurity, being small for gestational age, and having thrombocytopenia. Further large, prospective studies are required to better define the perinatal outcomes.

Anti-phospholipid antibodies increase non-apoptotic trophoblast shedding: a contribution to the pathogenesis of pre-eclampsia in affected women?

Pre-eclampsia is associated with trophoblast shedding-deportation and endothelial cell dysfunction. Anti-phospholipid autoantibodies increase a women's risk factor of developing pre-eclampsia. In this study we examined the hypothesis that anti-phospholipid antibodies alter the number and nature of trophoblasts shed from the placenta, and that phagocytosis of these altered trophoblasts results in endothelial cell activation. To investigate this we used a placental explant model in which explants were treated with anti-phospholipid antibodies. This treatment resulted in a doubling of the amount of trophoblast shed from the explants. Furthermore, the trophoblasts shed from anti-phospholipid antibody-treated explants were more readily phagocytosed by endothelial cells and subsequently caused the activation of the endothelial cells, as indicated by increased expression of endothelial cell surface ICAM-1 determined by cell-based ELISA, and monocyte adhesion as determined by flow cytometry. Confocal microscopy analysis of trophoblasts shed from anti-phospholipid antibody-treated or control explants demonstrated that anti-phospholipid antibodies, but not control antibodies, were internalised within trophoblasts shed from the explants, and this was accompanied by a reduction in the activity of caspases 3 and 7 in the shed trophoblasts as indicated by FLICA. These results suggest that anti-phospholipid antibodies are selectively transported into trophoblasts where they affect the regulation of the cell cycle leading to excess and aberrant death (necrotic or aponecrotic) and shedding of trophoblasts. If reflected in vivo this might explain, at least in part, how anti-phospholipid antibodies contribute to the pathogenesis of pre-eclampsia.

Annexin A2 is involved in antiphospholipid antibody-mediated pathogenic effects in vitro and in vivo

Antiphospholipid (aPL) antibodies recognize receptor-bound beta(2) glycoprotein I (beta(2)GPI) on target cells, and induce an intracellular signaling and a procoagulant/proinflammatory phenotype that leads to thrombosis. Evidence indicates that annexin A2 (A2), a receptor for tissue plasminogen activator and plasminogen, binds beta(2)GPI on target cells. However, whether A2 mediates pathogenic effects of aPL antibodies in vivo is unknown. In this work, we studied the effects of human aPL antibodies in A2-deficient (A2(-/-)) mice. A2(-/-) and A2(+/+) mice were injected with immunoglobulin G (IgG) isolated from either a patient with antiphospholipid syndrome (IgG-APS), a healthy control subject (IgG-normal human serum), a monoclonal anti-beta(2)GPI antibody (4C5), an anti-A2 monoclonal antibody, or monoclonal antibody of irrelevant specificity as control. We found that, after IgG-APS or 4C5 injections and vascular injury, mean thrombus size was significantly smaller and tissue factor activity was significantly less in A2(-/-) mice compared with A2(+/+) mice. The expression of vascular cell adhesion molecule-1 induced by IgG-APS or 4C5 in explanted A2(-/-) aorta was also significantly reduced compared with A2(+/+) mice. Interestingly, anti-A2 monoclonal antibody significantly decreased aPL-induced expression of intercellular cell adhesion molecule-1, E-selectin, and tissue factor activity on cultured endothelial cells. Together, these data indicate for the first time that A2 mediates the pathogenic effects of aPL antibodies in vivo and in vitro APS.

Anti-beta(2)-glycoprotein-I and anti-phosphatidylserine antibodies in women with spontaneous pregnancy loss

OBJECTIVE

To evaluate the role of anti-beta(2)-glycoprotein-I (anti-beta(2)GPI-ab) and anti-phosphatidylserine (aPS-ab) antibodies as a risk factor in both recurrent miscarriage (RM) and unexplained fetal losses (UFL).

DESIGN

Retrospective, cohort study.

SETTING

Vall d'Hebron University Hospital, Barcelona, Spain.

PATIENT(S)

122 pregnant women divided in two groups: study group of 54 women with RM and/or UFL and control group of 68 pregnant without RM history.

INTERVENTION(S)

Analysis of lupus anticoagulant, anticardiolipin antibodies, and anti-beta(2)GP1 and aPS antibodies.

MAIN OUTCOME MEASURE(S)

Comparison of aPL antibody between groups.

RESULT(S)

The prevalence of aPL positive results was 8 out of 54 (14.8%) in the study group and 3 out of 68 (4.41%) in the controls. In the RM subgroup, the prevalence was 3 out of 25 (12%) versus 3 out of 68 (4.4%), and 7 out of 34 (20.6%) versus 3 out of 68 (4.4%) in UFL subgroup. As a whole, the prevalence of anti-beta(2)GP1-ab in the RM/UFL group showed a difference compared with controls but not aPS-ab. In the RM women, anti-beta(2)GP1-ab was positive in 3 out of 25 (12%) versus 1 out of 68 (1.5%) in controls and in 4 out of 34 versus 0 out of 68 cases in women with UFL. In the RM subgroup, aPS-ab was positive in 1 out of 25 (4%) versus 2 out of 68 (2.9%) in control group and in 3 out of 34 versus 2 out of 68 cases in women with UFL.

CONCLUSION(S)

Our results suggest that anti-beta(2)GP1-ab but not aPS-ab is related to RM/UFL and should be considered as a pregnancy-loss risk factor.

Murine monoclonal antibody 26 raised against tetanus toxoid cross-reacts with beta2-glycoprotein I: its characteristics and role in molecular mimicry

PROBLEM

Studies on experimental antiphospholipid syndrome (APS) models proved that molecular mimicry between plasma protein beta(2)-glycoprotein I (beta(2)GPI) and structure within micro-organisms or their products, might be a cause for experimental APS. Considering the heterogeneity of polyclonal antiphospholipid antibodies (aPLs), it is important to define the precise characteristics of pathogenic aPLs. To avoid the influence of polyclonality and to further analyse the connection between molecular mimicry and APS, we produced monoclonal antibodies (MAbs) against tetanus toxoid (TTd) and tested their reactivity against beta(2)GPI.

METHOD OF STUDY

In this report, we analysed the characteristics of MAb26 raised against TTd and cross-reactive with beta(2)GPI: its binding properties in various in vitro immunoassays, its specific interactions with surface epitopes expressed on apoptotic cells and its role in vivo.

RESULTS

We have demonstrated that MAb26: (i) binds beta(2)GPI being immobilized on an appropriate surface: irradiated polystyrene plates, non-irradiated plates pre-coated with anionic phospholipids and polyvinylidene fluoride membrane; (ii) binds specifically to apoptotic but not to viable cells and the binding is beta(2)GPI-dependent; and (iii) induces a pathologic pregnancy outcome when passively injected into BALB/c mice.

CONCLUSION

This study concluded that certain subpopulations of antibodies raised against TTd and cross-reactive with beta(2)GPI, because of the molecular mimicry mechanism, could have pathologic potential.

Sixth meeting of the European Forum on antiphospholipid antibodies. How to improve the understanding of the antiphospholipid syndrome?

The main objective of these meetings is to promote international collaboration in various clinical and research projects. This paper is the summary of the 2007 Ljubljana meeting, and offers an overview of the proposed projects. The technical and methodological details of the projects will be published on the forum’s web site (http://www.med.ub.es/MIMMUN/FORUM/STUDIES.HTM).

Pathomorphologic and immunohistochemical study on the devastation of rat embryos by antiphospholipid antibody positive serum

PROBLEM

While relying on previous publications, our aim was to examine the morphologic changes, induced in early rat embryos by intra-uterine exposure to the low-molecular weight fraction of boiled human serum containing antiphospholipid antibodies (APLA) that had been obtained from women with antiphospholipid syndrome (APS).

METHOD OF STUDY

Human APLA-positive sera were pooled, boiled, centrifuged and separated by ultrafiltration. The molecular weight fraction lower than 30 kDa was used for the experiments. One hundred and fifty microlitres was injected into one uterine horn of 12 pregnant rats, 5 or 6 days after fertilization, while similarly prepared normal human serum or saline were injected into the contralateral horn. The rats were subsequently sacrificed. Serial sections, obtained from all uterine horns, were stained histologically and immunohistochemically. Normal embryos developed in the control uterine horns, while embryos in the experimental horns were destroyed rapidly.

RESULTS

Signs of apoptosis appeared 2 hr following the injection, and 4 hr later all the embryonic cells were apoptotically destroyed. There was only partial damage to cytotrophoblasts and intermediate trophoblasts.

CONCLUSION

These findings support the existence of a novel factor in the APLA-positive serum, causing a detrimental effect to the conceptus, without any relation to the antiphospholipid antibodies.

Updating on the pathogenic mechanisms 5 of the antiphospholipid antibodies-associated pregnancy loss

Anti-phospholipid antibodies (aPL) are risk factor for recurrent pregnancy loss and obstetrical complications. The mechanisms of aPL-mediated pregnancy failure are still a matter of research. Although aPL are associated with thrombosis, thrombotic events cannot explain all the miscarriages. There is evidence for a direct in vitro aPL effect on the trophoblast as shown by their binding; reduction of proliferation, human chorionic gonadotrophin release, in vitro invasiveness, adhesion molecule expression; and increased apoptosis. Such a direct reactivity is supported by the expression of beta2 glycoprotein (beta 2GP) I on trophoblast cell membranes. aPL/anti-beta 2GPI antibodies also bind to human decidual/endometrial cells in vitro and induce a pro-inflammatory phenotype. APL-mediated inflammatory processes at the placental level are apparently responsible for fetal loss at least in animal models. Both complement activation and pro-inflammatory cytokine/chemokine secretion have been shown to play a role. More recently, complement-induced tissue factor expression on infiltrating neutrophils was described as an additional pathogenic mechanisms mediated by aPL. As a whole, these findings do suggest that aPL may induce a defective placentation by acting at different levels without involving necessarily thrombotic events.

Clinical implication of natural killer cells and reproduction

The regulation of natural killer (NK) cells in the peripheral blood and endometrial layers has been associated with reproductive immunopathology such as recurrent spontaneous abortions (RSA), infertility of implantation failures, or pre-eclampsia. The placenta has a complex anatomical structure and different subsets of NK cells with various functional roles can directly interact with trophoblasts. NK cell subpopulations and their functions, putative roles of NK cells in peripheral blood and endometrium are reviewed in relation to RSA and infertility. An increase in NK cell numbers and /or activity in pre- or post-conceptional period in women with RSA or infertility with multiple implantation failures are a significant clinical concern. In addition, immuno-phenotypic characteristics of NK cells in these women support the changes for their increased activity status. Further studies are needed to explore underlying mechanism of NK cells in RSA, infertility, and other reproductive immunopathologies. Possible neurological and hormonal control of NK cells and NK cell interaction with various leukocyte populations need further investigation in women with reproductive failures.

The obstetric antiphospholipid syndrome

The association of persistent presence of circulating antiphospholipid antibodies and thromboembolic events, (recurrent) pregnancy loss or both is termed antiphospholipid syndrome. Pregnancies in women with the syndrome should be regarded as at high-risk for complications. Optimal management consisting of close follow-up and pharmacological treatment can result in about 70-80% live births. Apart from the laboratory diagnosis of the syndrome and pathophysiology, this review will focus on treatment during pregnancy.

Antiphospholipid antibodies: effects on trophoblast and endothelial cells

PROBLEM

Antiphospholipid syndrome (APS) may affect placental functions through several possible mechanisms. Interaction of antiphospholipid antibodies (aPL) with cells involved in the coagulation cascade is thought to produce a procoagulant state. Thrombotic placental pathology is however not specific for the APS.

METHOD OF STUDY

An analysis of published data.

RESULTS

It is now generally accepted that the clinically relevant aPL bind to proteins with affinity for phospholipids (PL), such as beta2-glycoprotein I (beta2-GPI). Following the attachment of beta2-GPI to trophoblast anionic PL, both molecules undergo conformational changes resulting in the exposure of cryptic epitopes within the structure of beta2-GPI. This may allow the subsequent binding of antibodies hence affecting trophoblast functions directly. Moreover anti-beta2-GPI antibodies induce the activation of endothelial cells (ECs), resulting in a proinflammatory state which favours the prothrombotic diathesis of the syndrome.

CONCLUSION

Numerous ameliorations in the APS knowledge have been introduced in the last few years. To have clarified the mechanism of antibody mediated damage on trophoblast and ECs represents an important step to explain the cellular events leading to pregnancy complications.

The detection of anti-β2-glycoprotein I antibodies is associated with increased risk of pregnancy loss in women with threatened abortion in the first trimester

OBJECTIVE

This study was designed to evaluate whether the detection of serum antiphospholipid autoantibodies may be useful in predicting pregnancy outcome in women with threatened abortion in the first trimester.

STUDY DESIGN

A group of 77 pregnant women of between 8 and 12 weeks' gestation with vaginal bleeding was tested for serum antiphospholipid, lupus anticoagulants, anticardiolipin, antinuclear antibodies, and anti-beta2-glycoprotein I antibodies, and was followed up until the spontaneous end of pregnancy. A control group composed of 15 healthy women with uncomplicated gestation was tested contemporarily for the same antibody panel.

RESULTS

Of the 77 patients with threatened abortion, 32 (41.5%) progressed to deliver at term and 45 (58.5%) experienced early pregnancy loss. Among the antibodies evaluated, only anti-beta2-glycoprotein I was significantly more frequent in those women whose pregnancy resulted in spontaneous abortion (22/45, 49%) than in those who progressed to term (6/32, 19%) or in the control group (2/15, 13%; p=0.004). This difference was specific to the IgM isotype (p=0.001). After adjustment by multivariate analysis, the odds ratio for pregnancy loss associated with a positive beta2-glycoprotein I antibody test was 5.18 (p=0.001).

CONCLUSION

The detection of anti-beta2-glycoprotein I antibodies is associated with an increased risk of pregnancy loss in women with threatened abortion in the first trimester.

Mechanisms of aPL-mediated thrombosis: effects of aPL on endothelium and platelets

Antiphospholipid antibodies (aPL) are associated with thrombosis and pregnancy loss in patients with systemic lupus erythematosus and antiphospholipid syndrome. Strong evidence demonstrates that aPL are pathogenic in vivo from studies that utilized animal models of thrombosis, endothelial cell activation, and pregnancy loss. However, the mechanisms by which aPL mediate disease are only partially understood, and our knowledge is limited by the polyspecificity of the antibodies, the multiple potential end-organ targets, and the variability of the clinical context in which the disease may present. This review discusses and summarizes the most current data available on molecular interactions and pathogenic mechanisms in antiphospholipid syndrome.

Do antiphospholipid antibodies cause preeclampsia and HELLP syndrome?

Antiphospholipid syndrome (APS) is associated with adverse pregnancy outcomes including preeclampsia, recurrent early pregnancy loss, fetal death, and intrauterine growth restriction. Approximately one third of women with APS will develop preeclampsia during pregnancy. The association between antiphospholipid antibodies (aPL) in the absence of the clinical syndrome and preeclampsia is less clear, and a causal relationship has not yet been proven. Testing for aPL should be considered in women with early-onset (< 34 weeks) severe preeclampsia, eclampsia, or HELLP (hemolysis, elevated liver enzymes, and low platelets) syndrome, especially when additional clinical features of APS are present. Prospective testing for aPL in women at risk for preeclampsia is not recommended. Current evidence does not justify inclusion of preeclampsia as a major criterion for APS, but preeclampsia could reasonably be included as a secondary or minor criterion in diagnosis when a patient has other clinical features of APS.

Placental thrombosis in experimental anticardiolipin antibodies-mediated intrauterine fetal death

PROBLEM

Anticardiolipin (aCL) antibodies are associated with stillbirths, recurrent miscarriages and recurrent in vitro fertilization implantation failure in women. Previous animal studies have demonstrated that these antibodies can cause early fetal demise and implantation failure in mice, but most previous studies have not allowed the immunized mice to proceed to the full term of gestation.

METHOD OF STUDY

Mice were immunized with either cardiolipin alone or cardiolipin in combination with beta2-glycoprotein I (beta2GPI) and have studied the effects of these antibodies on pregnancies which were allowed to progress to term.

RESULTS

Immunization with cardiolipin alone induced significant levels of anticardiolipin antibodies in mice, but immunization with a combination of cardiolipin and beta2GPI produced even higher levels of antibodies. Mice with elevated levels of anticardiolipin antibodies had poor pregnancy outcomes. This study confirms previous results that anticardiolipin antibodies cause early pregnancy losses and also demonstrates that these antibodies cause stillbirth-like late fetal demise. This study further demonstrated that very high levels of anticardiolipin antibodies cause intrauterine death by facilitating the thrombotic episode in placenta.

CONCLUSIONS

The present study concludes that the possible mechanism involves in stillbirth of aCL is possibly because of the thrombotic events of placenta.

Antiphospholipid Syndrome in Pregnancy

Antiphospholipid syndrome (APS) is frequently associated with complications during pregnancy. Miscarriage and maternal thrombosis are the most common problems, but prematurity, intrauterine growth retardation, pregnancy-induced hypertensive disorders, and pulmonary hypertension can complicate pregnancy as well. The correct treatment of these women requires an accurate preconceptual counseling and a close collaboration between obstetricians and physicians. Doppler studies of the umbilical and uterine arteries play an important role in predicting APS-related complications during pregnancy.

The antiphospholipid syndrome as a disorder initiated by inflammation: implications for the therapy of pregnant patients

Arterial thrombosis, venous thrombosis and morbidity during pregnancy, or a combination of these events, are clinical outcomes associated with antiphospholipid antibodies produced by patients with antiphospholipid syndrome (APS). Our understanding of the etiology and pathogenesis of the syndrome is limited, but it has generally been considered a thrombophilic disease and treatment has focused on anticoagulation. Agents such as aspirin and heparin, administered alone or in combination, are empirical treatments that are used in the management of obstetric patients with APS. Clinical features, such as heart valve abnormalities, thrombocytopenia and livedo reticularis, suggest multiple pathogenic mechanisms and provide other therapeutic targets. Findings from research in animal models of APS challenge the dogma that this syndrome is a noninflammatory, thrombotic disease and provide evidence that activation of complement is crucial for complications in pregnancy. These studies, in addition to evidence of inflammatory-mediated tissue damage in placentae of patients with APS, suggest that therapy should also be directed towards preventing inflammation. This Review describes the potential mechanisms of tissue injury by antiphospholipid antibodies, the management of pregnant patients with APS and how heparin therapy might inhibit the pathogenic mediators of disease.

Antiphospholipid reactivity against cardiolipin metabolites occurring during endothelial cell apoptosis

We have recently shown that cardiolipin (CL) and its metabolites move from mitochondria to other cellular membranes during death receptor-mediated apoptosis. In this study, we investigate the immunoreactivity to CL derivatives occurring during endothelial apoptosis in patients with antiphospholipid syndrome (APS) and systemic lupus erythematosus (SLE). We compared the serum immunoreactivity to CL with that of its derivatives monolysocardiolipin (MCL), dilysocardiolipin (DCL), and hydrocardiolipin (HCL) by means of both enzyme-linked immunosorbent assay and thin-layer chromatography (TLC) immunostaining. In addition, we investigated the composition of phospholipid extracts from the plasma membrane of apoptotic endothelial cells and the binding of patients' sera to the surface of the same cells by using high-performance TLC and immunofluorescence analysis. The average reactivity to MCL was comparable with that of CL and significantly higher than that for DCL and HCL in patients studied, both in the presence or in the absence of beta₂-glycoprotein I. Of relevance for the pathogenic role of these autoantibodies, immunoglobulin G from patients' sera showed an increased focal reactivity with the plasma membrane of endothelial cells undergoing apoptosis. Interestingly, the phospholipid analysis of these light membrane fractions showed an accumulation of both CL and MCL. Our results demonstrated that a critical number of acyl chains in CL derivatives is important for the binding of antiphospholipid antibodies and that MCL is an antigenic target with immunoreactivity comparable with CL in APS and SLE. Our finding also suggests a link between apoptotic perturbation of CL metabolism and the production of these antibodies.

Role of anti-β2 glycoprotein I antibodies in antiphospholipid syndromeglycoprotein I antibodies in antiphospholipid syndrome

Antiphospholipid syndrome (APS) is characterized by the presence of recurrent venous/ arterial thrombosis and fetal losses associated with a family of auto-antibodies directed against phospholipid (PL)-binding proteins. Among them, beta2 glycoprotein I (beta2GPI) is the most important. As a plasma cationic protein, beta2GPI binds to anionic PLs involved in several fluid-phase coagulation steps, and more importantly, it can be expressed on the surface of different cell types. Anti-beta2GPI antibodies recognize the molecule expressed on endothelial cells, platelets, monocytes, and trophoblast cells. Once bound, the antibodies trigger in vitro cell signaling that modulates biological responses potentially responsible for pathogenic mechanisms. Experimental animal models have supported the in vivo pathogenic role of anti-beta2GPI antibodies in both thrombosis and fetal loss models.

Pathogenic role of anti-β2-glycoprotein I antibodies on human placenta: functional effects related to implantation and roles of heparin

Most of the clinical manifestations of the antiphospholipid syndrome (APS) can be related to thrombotic events; however, placental thrombosis cannot explain all of the pregnancy complications that occur in women with this syndrome. In this regard, it has been hypothesized that antiphospholipid (aPL) antibodies can directly attack trophoblasts, but it is still unclear what pathogenetic mechanisms play a role and which aPL antibodies subpopulations are involved. Although it has been assumed that aPL antibodies are directed against anionic phospholipids (PLs), current advances in the field suggest that antibodies to PL-binding plasma protein such as beta2-glycoprotein-I (beta2-GPI) are the clinically relevant aPL antibodies. It appears that following the attachment of beta2-GPI to PLs, both molecules undergo conformational changes that result in the exposure of cryptic epitopes within the structure of beta2-GPI allowing the subsequent binding of antibodies. aPL antibodies detected by anti-beta2-GPI assays are associated with fetal loss. However, there is still debate on how the antibodies might induce the obstetrical manifestations. The significantly improved outcome of pregnancies treated with heparin has stimulated interest in the drug's mechanisms of action. Several mechanisms could explain its beneficial effects, because in addition to a direct effect of heparin on the coagulation cascade, it might protect pregnancies by reducing the binding of aPL antibodies, reducing inflammation, facilitating implantation and/or inhibiting complement activation. Further investigations are needed to better understand how aPL antibodies induce obstetric complications and to better clarify the functional role of heparin in the human placenta leading to more successful therapeutic options.

Antiphospholipid syndrome and pregnancy

Since the 1960s, antiphospholipid antibodies have been known to be associated with repeated miscarriages and fetal losses. Other complications of pregnancy, such as preterm birth, with pre-eclampsia or severe placental insufficiency were also frequently reported and are included in the current classification criteria of the antiphospholipid syndrome. The titer, isotype or antigen specificity of the antibodies may be important in risk determination. The pathogenesis of pregnancy failures is not only linked to the thrombophilic effect of antiphospholipid antibodies but also to a direct effect of antibodies on trophoblast differentiation and invasion. The study of experimental animal models provided sound evidence of the pathogenic role of antiphospholipid antibodies both in lupus-prone and -naive mice. The classification of pregnant antiphospholipid syndrome patients as being at a 'high risk' has completely changed their prognosis due to obstetric monitoring and the application of effective therapy. In fact, despite the high rates of complications and preterm delivery, a successful outcome can now be achieved in a large majority of cases.

Natural antibodies, autoantibodies and complement activation in tissue injury

Ischemia/reperfusion-induced tissue damage is a significant problem occurring in multiple clinical conditions. Antibodies and complement activation contribute significantly to this pathology. Mice deficient in complement receptors 1 and 2 fail to produce a component of the natural antibody repertoire that binds to ischemia-conditioned tissues and activate complement. In contrast, mice prone to autoimmunity display accelerated tissue injury that results from the binding of autoantibodies to injured tissues. The specificity and production of natural antibodies, their role in autoimmunity and the mode of complement activation are reviewed from the perspective of the processes involved in ischemia/reperfusion-induced tissue damage.

Current concepts on the pathogenesis of the antiphospholipid syndrome

The antiphospholipid syndrome (APS) is an important cause of acquired thrombophilia. It is characterized by the core clinical manifestations of thrombosis, either venous or arterial, and in women it can also be associated with recurrent fetal loss. The detection of persistently elevated levels of antiphospholipid antibodies (aPL Abs) is a requisite laboratory feature for the diagnosis to be made. The dominant antigenic targets in APS are beta 2-glycoprotein I (β2-GPI) and prothrombin. There is an accumulating body of experimental evidence that suggests that specific subgroups of aPL Abs may directly contribute to disease pathogenesis. This review critically examines the experimental evidence underlying the various propositions made to explain how these antibodies may predispose to disease in humans. Furthermore, it also examines the evidence relating to the immunologic mechanisms that may contribute to the breakage of peripheral tolerance in this disorder. Delineating the strengths and limitations of the experimental evidence accumulated thus far will hopefully stimulate further experimentation toward achieving the ultimate goal of precisely defining the dominant pathogenic mechanisms operational in APS. This may pave the way for the development of improved therapies.

Acquired Thrombophilia during Pregnancy

Acquired thrombophilic states are common causes of thrombosis and other forms of pregnancy-associated complications. A growing body of evidence is available to guide the use of anticoagulants in patients who have antiphospholipid antibodies; unfortunately, the results of these studies are conflicting, and solid, evidence-based treatment recommendations cannot be made. Other forms of acquired thrombophilia are uncommon or of unknown clinical significance. Treatments aimed at mitigating the impacts of these states lack clear evidence to support their use.

Autoimmunity and pregnancy: autoantibodies and pregnancy in rheumatic diseases

In women who suffer from rheumatic diseases (RDs) the risk of repeated fetal loss, intrauterine growth restriction, and preterm birth remains higher than in the general population. Antiphospholipid antibodies are frequently observed in patients with systemic lupus erythematosus (SLE). They are associated with recurrent pregnancy losses that may occur at any age of gestation. The cause of fetal death is believed to be intraplacental thrombosis, although other pathologic mechanisms have been described. A recent study has described the increased frequency of learning disabilities in the offspring of SLE patients; case reports of neonatal thrombosis are very rare. Transplacental passage of IgG anti-Ro/SS-A antibodies is linked to neonatal lupus (2%). The main manifestation is congenital heart block (CHB) due to the binding of anti-Ro/SS-A antibodies to cardiac conduction tissue and to the consequent inflammatory/fibroid reaction. Neonatal lupus also includes cutaneous, hematologic, and hepatobiliary manifestations, which are typically transient. Incomplete CHB can be treated with fluorinated corticosteroids to prevent the progression and decrease inflammation. Intravenous immunoglobulin, decreasing the tranplacental passage of anti-Ro/SS-A, has been proposed as prophylactic therapy in patients who had one or more child with CHB. Transplacental passage of antiplatelet antibodies, in about 10% of mothers with SLE, can induce thrombocytopenia in the fetus or the neonate. Patients with RD have a higher incidence of anxiety and depression compared to the general population, interfering with parenthood and the upbringing of children.

Anti-beta-2 glycoprotein I antibodies affect Bcl-2 and Bax trophoblast expression without evidence of apoptosis

Antiphospholipid antibodies (aPLs) reacting with beta-2 glycoprotein I (beta2GPI) have been associated with recurrent fetal loss and pregnancy complications. The aim of the study was to investigate whether aPLs with anti-beta2GPI specificity induce apoptosis of human trophoblasts in vitro. To this end, human anti-beta2GPI monoclonal IgM derived from a patient with antiphospholipid syndrome and a human irrelevant monoclonal IgM were incubated with human trophoblast cell cultures for 24, 48, and 72 h. In all the cultures we evaluated: (i) Bcl-2 and Bax mRNA and protein expression by Western blot and reverse transcription polymerase chain reaction (RT-PCR), respectively; (ii) DNA fragmentation by a commercial ELISA kit and by agarose gel electrophoresis; and (iii) the percentage of cells reactive with the monoclonal antibody (MAb) M30 by indirect immunofluorescence. The results were: Bcl-2/Bax ratio increased in untreated trophoblast cells during the time of culture, showing the highest values detectable after 72 h (2.68 and 2.28 at protein and mRNA levels, respectively). Cell incubation with anti-beta2GPI MAbs induced a significant Bcl-2/Bax ratio reduction in comparison with untreated cells (1.22 and 1.28 at protein and mRNA levels, respectively, after 72 h incubation). No significant difference was detected after cell exposure to irrelevant MAbs. However, neither DNA fragmentation nor increase in cells positive for the caspase-cleaved epitope of cytokeratin 18 cytoskeletal protein (M30) was found. In Conclusion, anti-beta2GPI antibodies react with trophoblast cells and reduce the Bcl-2/Bax ratio, but without any clear apoptotic effect.

Management of Antiphospholipid Syndrome in Pregnancy

APS pregnancy losses are one of the most common treatable causes of recurrent pregnancy loss. Clinical trials have helped in delineating the dangers of prednisone use in pregnancy, and suggest that heparin and aspirin regimens are preferred. However, the clinical trials suffer from the lack of uniform definition of antiphospholipid antibody positivity, from inclusion of women with different past pregnancy histories, and from different timing of the onset of the therapeutic modalities tested. New research on the role of complement activation in murine APS pregnancy loss may change therapeutic options in the future.

Low-molecular weight heparin induces in vitro trophoblast invasiveness: role of matrix metalloproteinases and tissue inhibitors

Heparin is used widely for the prevention of pregnancy loss in pregnant women with thrombophilia. However, it is still unknown if heparin may be able to affect trophoblast functions. Therefore, we investigated the hypothesis that low-molecular weight heparin (LMWH) might regulate in vitro trophoblast invasiveness and placental production of matrix metalloproteinases (MMPs) and tissue inhibitors (TIMPs). In the first-trimester placental tissue, the MMP-9 expression was observed in both villous and extravillous cytotrophoblast cells, and MMP-2 mainly in villous cytotrophoblast. In human choriocarcinoma cells (JAR), MMP-2 was the dominant form. Heparin significantly enhanced both pro-MMPs and the active forms, and increased Matrigel invasiveness of extravillous trophoblast and choriocarcinoma cells. In choriocarcinoma cells the heparin effect was also indirect, inducing a significant decrease in TIMP-1 and TIMP-2 protein expressions and mRNAs. The present data suggest that the increase in trophoblast invasion by heparin is due to a specific protein playing a role in placental invasion. These observations may help in understanding the effects of heparin treatment during pregnancy.

[Systematic lupus erythematosus and antiphospholipid syndrome during pregnancy]

Women with systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS) are subject to several complications during pregnancy, including reactivation of SLE, thrombosis, miscarriage, neonatal lupus, pregnancy-induced hypertension, pulmonary hypertension and drug toxicity. Correct management of these patients requires combined medical-obstetric care, close surveillance of baby's growth and well-being, control of SLE activity and correct thromboprophylaxis. With good care, most pregnancies in women with SLE and APS end successfully.

Inherited Thrombophilia: Treatment during Pregnancy

OBJECTIVE

Inherited thrombophilia is associated with thromboembolic events and/or poor obstetric outcome. We evaluated the pregnancy outcome in women with inherited thrombophilia treated with low-molecular-weight heparin (LMWH).

METHODS

38 thrombophilic women with a history of thromboembolic events and/or poor obstetric outcome were treated during their 39 consecutive pregnancies with LMWH from pregnancy verification until 4-6 weeks in puerperium. A fixed dose of enoxaparin 4,000 IU/day (except 1 case who required nadroparin 0.3 ml/day) was administered in most cases, adopting a higher dose (6,000 IU/day to 6,000 IU twice a day) in those with previous thromboembolic events.

RESULTS

In the treated women, all had a good obstetric outcome, whereas in the previous untreated pregnancies (n = 78), the rate of fetal loss (early and late) was 76.9%, only 12 live infants survived (66.6%). Moreover, birth weight resulted significantly higher in live infants born to treated pregnancies in comparison to that of previous untreated pregnancies (p = 0.009). No maternal thrombosis or major bleeding complications were recorded.

CONCLUSIONS

The treatment with LMWH improved pregnancy outcome resulting effective and safe in thrombophilic women with a history of thromboembolic events and/or poor obstetric outcome.

Aspirin Desensitization in the Treatment of Antiphospholipid Syndrome during Pregnancy in ASA-sensitive Patients

PROBLEM

Antiphospholipid syndrome (APS) is associated with thrombosis and poor pregnancy outcome in the presence of antiphospholipid antibodies (aPL). Patients with aPL have a high risk of foetal loss. However, with low-dose aspirin (acetylsalicylic acid; ASA) in combination with subcutaneous heparin, the chances of full-term delivery increase. Nevertheless, ASA treatment is avoided in pregnant, ASA-sensitive women with APS.

METHODS

Rapid oral challenge-desensitization to ASA was performed in four pregnant women with a history of APS and aspirin sensitivity. In three patients, desensitization was performed during pregnancy and before the next pregnancy in the fourth. Desensitization was carried out in the ICU using increasing doses of aspirin (0.1-125 mg) over a 24-hr period.

RESULTS

Successful ASA desensitization was achieved in all the patients. No severe side effects occurred during the desensitization test. Only one patient required a small oral dose of antihistamines.

CONCLUSIONS

Aspirin desensitization may be a safe alternative even during pregnancy if carefully monitored and permit patients with APS to receive treatment with ASA. This would constitute a new indication in pregnant women with APS and ASA sensitivity.

Antiphospholipid antibodies and coagulation defects in women with implantation failure after IVF and recurrent miscarriage

Evaluation of patients with IVF implantation failure or recurrent miscarriage often frustratingly fails to elicit any particular cause for their problem. Testing for antiphospholipid antibodies or thrombophilia is commonly carried out, and interpretation of results in the light of the current evidence is extremely difficult. This paper reviews the purported pathogenetic mechanisms and clinical associations between both antiphospholipid antibodies and inherited thrombophilias, and reproductive failure. The current management strategies are also critically evaluated and recommendations are made for optimal, evidence-based clinical practice.

Preliminary prospective study of the endocrinology of conception cycles and early pregnancy in women with antiphospholipid syndrome treated with low molecular weight heparin

OBJECTIVE

To examine whether there were any differences in the endocrinological profiles during conception cycle and early pregnancy between a control group and women with a history of recurrent miscarriage that was caused by antiphospholipid syndrome and that was treated with aspirin and low molecular weight heparin.

DESIGN

Prospective observational study.

SETTING

Recurrent Miscarriage Clinic, Department of Obstetrics and Gynaecology in a tertiary care centre.

PATIENT(S)

Five women with recurrent pregnancy loss were recruited as cases, whereas another five women having natural cycle donor insemination were used as control.

INTERVENTION(S)

Serial measurement of serum beta-hCG, activin A, and inhibin A was performed from postovulatory day 12 until 11 weeks of gestation.

MAIN OUTCOME MEASURE(S)

Comparison of levels of beta-hCG, activin A, and inhibin A at the time of conception onwards till 11 weeks in the two groups.

RESULT(S)

There were no significant differences between the two groups.

CONCLUSION(S)

There does not appear to be any obvious endocrinological alteration in the conception cycle of women with antiphospholipid syndrome compared with a control group. Furthermore, the initiation of heparin does not produce a significant change in activin A and inhibin A levels.

Changes of complement in recurrent abortion and pregnancy loss with antiphospholipid antibody positive

In order to know the comlement activation, the changes of compliment were evaluated in recurrent abortion and pregnancy loss patients with antiphospholipid antibody (APA) positive. Serum samples were taken from 82 patients with more than 2 recurrent abortion patients and/or pregnancy loss. Fifty eight cases of 82 patients were APA and antinuclear antibody negative without autoimmune disease. Anticardiolipin antibody (ACA), anti CL/beta2-GPI antibody (CL/beta2-GPI) were measured using ELISA. Lupus anticoagulant (LAC) was measured using diluted RVVT. CH50 and C3 and C4 were measured as complements. The number of positive cases of ACA, CL/beta2-GPI, LAC was 23, 9 and 5 cases, respectively.

RESULTS

The levels (mean+/-SD) of CH50, C3 and C4 in ACA positive and negative cases were 38.8+/-8.3 U/ml, 82.7+/-20.1 mg/dl, 18.5+/-5.7 mg/dl and 42.4+/-6.9 U/ml, 93.5+/-17.6 mg/dl, 21.1+/-4.6 mg/dl, respectively. The levels of CH50, C3 and C4 in positive cases were significantly lower than negatives. The levels of CH50, C3 and C4 in CL/beta2-GPI and LAC positive cases were also significantly lower than negatives.

CONCLUSION

The comlement activation was demonstrated in recurrent abortion and pregnancy loss with antiphospholipid antibody positive.