In vitro effect of antiphospholipid antibody-containing sera on basal and gonadotrophin releasing hormone-dependent human chorionic gonadotrophin release by cultured trophoblast cells

Trophoblast Cell Function in the Antiphospholipid Syndrome

Antiphospholipid syndrome (APS) is a complex thrombo-inflammatory autoimmune disease characterized by the presence of antiphospholipid antibodies (aPL). Women with APS are at high risk of recurrent early pregnancy loss as well as late obstetrical complications-premature birth due to placental insufficiency or severe preeclampsia. Accumulating evidence implies that vascular thrombosis is not the only pathogenic mechanism in obstetric APS, and that the direct negative effect of aPL on the placental cells, trophoblast, plays a major role. In this review, we summarize the current findings regarding the potential mechanisms involved in aPL-induced trophoblast dysfunction. Introduction on the APS and aPL is followed by an overview of the effects of aPL on trophoblast-survival, cell function and aPL internalization. Finally, the implication of several non-coding RNAs in pathogenesis of obstetric APS is discussed, with special emphasis of their possible role in trophoblast dysfunction and the associated mechanisms.

IVIG in APS pregnancy

For more than two decades, the intravenous administration of high doses of IgG pooled from the plasma of healthy donors (immune globulin therapy, also known as ‘IVIG’) has benefited patients with a variety of autoimmune disorders. A potential therapeutic role of IVIG in the prevention of thrombosis and of miscarriages in antiphospholipid syndrome (APS) has been postulated. Multicenter randomized controlled trials attempted to define the role of IVIG in preventing pregnancy complications in APS indicate that simple anticoagulation could not be completely satisfactory, and certain patient subgroups might take advantage of IVIG therapy alone or in combination with heparin.

Human IgG Antinuclear Antibodies Induce Pregnancy Loss in Mice by Increasing Immune Complex Deposition in Placental Tissue: In Vivo Study

PROBLEM

A threefold higher prevalence of antinuclear antibodies (ANA) has been reported in patients with recurrent pregnancy loss (RPL). Nevertheless, the role of ANA in reproductive failure is still unclear. The aim of this study was to investigate the role of ANA during early pregnancy in vivo.

METHOD OF STUDY

We used pregnant mice treated with immunoglobulin G (IgG) obtained from normal healthy subjects (NHS); ANA(+) sera of patients with RPL; and ANA(+) sera from women with uncomplicated pregnancies (HW). Placental immunohistochemical/immunofluorescence staining was performed to detect complement and immune complex deposition. ELISA was performed to evaluate complement levels.

RESULTS

ANA(+) IgG from RPL women significantly increased embryo resorption rate, reduced C3, and increased C3a serum levels compared to NHS IgG or ANA(+) -HW IgG. Increased C3 deposition and increased immune complex staining in placental tissues from mice treated with ANA(+) -RPL IgG fraction compared to NHS- and ANA(+) -HW-IgG-treated mice were found.

CONCLUSION

ANA(+) IgG injection in mice is able to induce fetal resorption and complement activation. The presence on placental tissues of immune complexes and complement fragments suggests the complement activation as a possible mechanism of placental damage.

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.

Intravenous immunoglobulin therapy for aspirin-heparinoid-resistant antiphospholipid syndrome

We encountered a woman who had a history of repeated fetal losses and positive tests for lupus anticoagulant, phosphatidylserine-dependent antiprothrombin (aPS/PT) IgG, IgM and kininogen-dependent antiphosphatidylethanolamine (aPE) IgG, IgM. Her previous pregnancy had ended in intrauterine fetal death at 24 weeks of gestation despite a therapy of low-dose aspirin, prednisolone and danaparoid. During the present pregnancy, she was treated with repeated intravenous infusions of immunoglobulin (IVIg) together with low-dose aspirin, prednisolone and heparin. When thrombocytopenia developed, she delivered a female baby weighing 2,152 g at 34 weeks of gestation by cesarean section. Titers of aPS/PT IgM and aPE IgM were reduced or maintained at low levels by repeated IVIg therapies. The IVIg therapy might be effective for aspirin-heparinoid-resistant antiphospholipid syndrome.

14th International HLA and Immunogenetics Workshop: Report from the reproductive immunology component

The aim of the study was to investigate whether human leukocyte antigen (HLA) allele sharing between partners or the maternal killer immunoglobulin-like receptor (KIR) repertoire is associated with recurrent spontaneous abortion (RSA) and repeated implantation failure after in vitro fertilization (IVF)/embryo transfer. From a total population of 158 RSA couples, 40 couples with repeated implantation failures (IVF) and 81 control couples, reported by five different laboratories, analysis was performed for (a) HLA sharing in 50 RSA, 31 IVF and 31 control couples, (b) DQA1*0505 sharing/homozygosity among partners in 108 RSA, 40 IVF and 36 control couples, and (c) the women's KIR repertoire in 46 RSA, 26 IVF and 36 control wives. RSA couples were divided into alloimmune aborter (RSAallo) and autoimmune aborter (RSAauto). The results oppose to the suggestion that increased HLA sharing per se or a limited maternal KIR repertoire predisposes to RSA or IVF failure. However, the observation of a slightly higher percentage of DQA1*0505 sharing in the RSAauto and the IVF group needs further investigation. The ratio of inhibitory to activating KIR (actKIR) was slightly lower in RSAallo and IVF women (1.9 vs 2.6 in controls), while in a high percentage of these women, the standard receptors of the KIR A haplotype were combined with actKIR/s of the haplotype B (66.6% and 45.4% vs 20% and 15.3% in RSAauto and control groups). This may suggest a possible involvement of actKIRs in embryo implantation and the maintenance of pregnancy and also requires further investigation.

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.

Recurrent miscarriage

Many human conceptions are genetically abnormal and end in miscarriage, which is the commonest complication of pregnancy. Recurrent miscarriage, the loss of three or more consecutive pregnancies, affects 1% of couples trying to conceive. It is associated with psychological morbidity, and has often proven to be frustrating for both patient and clinician. A third of women attending specialist clinics are clinically depressed, and one in five have levels of anxiety that are similar to those in psychiatric outpatient populations. Many conventional beliefs about the cause and treatment of women with recurrent miscarriage have not withstood scrutiny, but progress has been made. Research has emphasised the importance of recurrent miscarriage in the range of reproductive failure linking subfertility and late pregnancy complications and has allowed us to reject practice based on anecdotal evidence in favour of evidence-based management.

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.

Antiphospholipid antibodies in serum and follicular fluid--is there a correlation with IVF implantation failure?

BACKGROUND

Antiphospholipid antibodies (aPLs) are associated with infertility, but the mechanism underlying this statistical association is currently obscure. We aimed to investigate the finding that aPLs are concentrated in follicular fluid and to establish if this is associated with a poorer outcome from IVF.

METHODS AND RESULTS

In 19.2% of 99 women undergoing IVF, at least one aPL was detected in their serum and/or follicular fluids, but the antibody levels in follicular fluid were not higher than in serum. Women with aPLs had a lower implantation rate (14%) than women without these antibodies (24.1%), but this difference was not significant (P=0.127). There was also a non-significant reduction in the live birth rate for women with aPLs. In a parallel investigation, 10 sheep immunized with beta2 glycoprotein I (beta2GPI) or irrelevant control antigens showed strong immune responses, but there were no significant differences between the levels of antibodies in the follicular fluid or serum from beta2GPI or control immunized sheep.

CONCLUSION

aPLs do not appear to be selectively concentrated in follicular fluids and, when present, do not adversely affect the reproductive outcome of women undergoing IVF.

Current debates in antiphospholipid syndrome: the acquired antibody-mediated thrombophilia

Antiphospholipid (APL) syndrome is the most common form of acquired thrombophilia. It can cause significant morbidity and even mortality. The term "APL antibodies" represents a heterogeneous group of antibodies associated with this disorder. Currently no single assay can identify every APL antibody. Clinically relevant APL antibodies are mainly anticardiolipin antibodies (ACA) detected by solid phase enzyme-linked immunosorbent assay (ELISA) and lupus anticoagulants (LA) demonstrated by in vitro coagulation assay. However, there are some other antibodies associated with the APL syndrome (i.e., subgroup APL antibodies). ACAs, LAs, and subgroup APL antibodies represent intersecting, but non-identical, subsets of autoantibodies. Thus, those autoantibodies may coexist or may occur independently. Any organ system and any size of vessel can be affected during the clinical course of the disease. Therefore, the APL syndrome can manifest itself in a wide variety of clinical thrombotic features. Fetal loss and pregnancy morbidity represent a specific challenge. Despite tremendous advances in the understanding of the pathogenesis of APL syndrome during the past decade, the mainstay of management is still anticoagulation. However, there is no general agreement regarding the duration and intensity of anti-coagulant therapy. In this review, we focused on the current dilemmas and their present clarifications in the wide clinicopathologic spectrum of APL syndrome and APL antibody-related distinct pathologic conditions.

Immunologic manipulation for the threatened fetus

Management of the pregnant woman with the antiphospholipid syndrome (APLS) has improved over the last 10 years. The recurrent pregnancy loss that is associated with this disease is managed with prophylactic low dose aspirin and heparin therapy. This therapy leads to a 40% absolute risk reduction in pregnancy loss. However, many women still fail to deliver a live infant despite this therapy so immunologic manipulation of the mother's disease in this group needs to be considered. Intravenous immunoglobulin and plasma exchange may have a role. New immunosuppressive drugs such as tacrolimus have yet to be tried. Monoclonal antibodies to B cells, B-cell growth factors, complement proteins and integrin molecules, all of which appear to play a role in the disease process, may also offer patients some hope. Similarly, biologics such as C1 esterase inhibitor protein, cell surface complement regulator proteins or interleukin-3 need to be tried given their efficacy in models of antibody-induced cell injury.

Antiphospholipid antibodies: biological basis and prospects for treatment

Antiphospholipid antibodies (aPL) are autoantibodies that are associated with recurrent reproductive failure and thrombotic disease. There are two well-characterised aPL, lupus anticoagulant and anticardiolipin antibodies. aPL were originally thought to bind to negatively-charged phospholipids but it is now clear that the title aPL is a misnomer and that the antigens for these autoantibodies are actually phospholipid-binding proteins. Chief amongst these phospholipid-binding proteins are prothrombin and beta(2) glycoprotein I. This review concentrates on the role of beta(2) glycoprotein I in the reproductive failure caused by aPL. Exactly how aPL cause reproductive failure remains unknown but there is emerging evidence that the antibodies may have several different adverse effects on trophoblasts. There is also evidence questioning the traditional hypothesis that fetal demise is secondary to thrombosis of the utero-placental circulation. Heparin is commonly used to treat pregnant women with aPL but if these antibodies do not cause fetal demise primarily by a thrombotic mechanism a question must be raised over the role of heparin. However, heparin binds to many proteins including beta(2) glycoprotein I and it is possible that the reported beneficial effects of heparin in aPL-affected pregnancies may be due to the ability of heparin to prevent the interaction of aPL and beta(2) glycoprotein I.

Regulated expression of signal transducer and activator of transcription, Stat5, and its enhancement of PRL expression in human endometrial stromal cells in vitro

Differentiation of human endometrium during the secretory phase of the menstrual cycle is characterized by expression of a variety of genes implicated in the establishment and maintenance of pregnancy. An increased abundance of signal transducers and activators of transcription (Stats) in the secretory phase suggests Stat5 as a component of the differentiation of endometrium in response to ovarian hormone stimulation in vivo. Decidualization is initiated in a subset of endometrial stromal cells (ESC) in vivo during the secretory phase, but it is unclear whether regulated expression of Stat5 is a feature of these cells. Here, therefore, the abundance and subcellular distribution of Stat5 in ESC after a decidualization stimulus of cAMP plus medroxyprogesterone acetate (MPA) has been investigated in vitro. Western blotting revealed an increase in the apparent abundance of Stat5a and Stat5b, in the cytosolic and nuclear fractions, at 2, 3, and 4 d after stimulation. The potential functional relevance of this increase in Stat5 is suggested by the ability of transiently transfected Stat5a or Stat5b to significantly enhance the response of the decidual PRL promoter to cAMP/MPA and attenuation of the response to cAMP/MPA by dominant negative Stat5. Recent evidence suggests endometrial differentiation, including PRL production, as a possible target of antiphospholipid antibodies (aPL) prevalent in recurrent miscarriage. Monoclonal antibody, ID2, which has similar reactivity as human aPL, significantly decreased the apparent abundance of nuclear Stat5b in response to cAMP/MPA and was associated with decreased decidual PRL promoter activation and PRL secretion. Regulated expression of Stat5 is therefore a component of decidual differentiation of human ESC and contributes significantly to activation of the decidual PRL promoter. Alteration of this process by an aPL component suggests decidual differentiation as a potential clinical target in recurrent early miscarriages.

Is interleukin-3 important in antiphospholipid antibody-mediated pregnancy failure?

OBJECTIVE

To investigate the effect of interleukin-3 (IL-3) on trophoblast proliferation and expression of beta2-glycoprotein I.

DESIGN

In vitro cell culture using primary trophoblasts and the cell lines Jeg-3, Jar, and BeWo.

SETTING

Department of Obstetrics and Gynaecology, University of Auckland.

PATIENT(S)

Women with normal pregnancies.

INTERVENTION(S)

Increasing amounts of IL-3 were added to cultures of primary human trophoblasts, cell lines, or cells treated with a proliferation inhibiting antiphospholipid-like antibody. RNA was extracted from primary human trophoblasts or cell lines.

MAIN OUTCOME MEASURE(S)

We examined basal and IL-3-stimulated cellular proliferation by [3H] thymidine incorporation assay and secretion of beta2-glycoprotein I into culture medium by semiquantitative immunoblot analysis. Reverse transcriptase-polymerase chain reaction analysis was used to demonstrate the presence of IL-3 receptor transcripts.

RESULT(S)

The IL-3 treatment did not induce proliferation of highly purified primary trophoblast cultures or cell lines but did induce proliferation of contaminating CD45+ cells in trophoblast cultures. The IL-3 did not overcome the antiproliferative effect of an antiphospholipid-like monoclonal antibody on trophoblast. Secretion of beta2-glycoprotein I by trophoblast cultures was time dependent but unaltered by IL-3 treatment.

CONCLUSION(S)

Our results question the proposed importance of IL-3 in antiphospholipid antibody-mediated fetal death.

Antiphospholipid syndrome and recurrent miscarriages

Sixty percent of recurrent spontaneous abortions are unexplained. Antiphospholipid syndrome is a multisystem disease with the predominant features of venous and arterial thrombosis, recurrent pregnancy loss, foetal death and the presence of antiphospholipid antibodies. Many epidemiological studies focus on antiphospholipid autoantibodies syndrome (APS) as a cause of recurrent spontaneous abortion (RSA). It is found that 7-25% of RSA would have APS as the main risk factor. 'Association not being synonymous with cause', the proportion of abortions due to the APS is difficult to estimate for several reasons: definition of recurrent abortion is variable, the assays for antiphospholipid antibodies are not well standardised, inclusion of patients in the study group according to the antibodies titre is author dependent. Recent studies suggest association of antiphospholipid antibodies syndrome not only with recurrent abortions but also with infertility. New mechanisms are described by which antiphospholipid antibodies could cause placental thrombosis and infarction, acting directly on the surface anticoagulant expressed on trophoblastic cells. Only lupus anticoagulant (LA) and anticardiolipin antibodies (aCL) assays are sufficiently standardised to be usable in routine. Testing for other antiphospholipid antibodies (aPLs) should remain investigational. Several treatments have been proposed: low doses of aspirin, low or immunosuppressive doses of corticosteroids, and preventive or effective dose of heparin, intravenous immunoglobulin.

Antiprothrombin autoantibodies in severe preeclampsia and abortion

PURPOSE

We examined the levels of autoantibodies against prethrombin-1 and fragment-1 in pregnant women to determine the type of autoantibodies that were associated with severe preeclampsia or spontaneous abortion.

SUBJECTS AND METHODS

We measured autoantibodies bound to prothrombin, prethrombin-1, and fragment-1 by using an enzyme-linked immunosorbent assay (ELISA) in 12 healthy nonpregnant women, 36 women with normal pregnancies, 28 pregnant women with severe preeclampsia, and 19 pregnant women who subsequently had spontaneous abortion.

RESULTS

Plasma samples in 10 (36%) of the 28 women with severe preeclampsia and 11 (58%) of the 19 women with spontaneous abortion were positive for antiprothrombin antibodies as compared with 3 (9%) of the 36 women with normal pregancies. All 11 of the positive samples from women who had spontaneous abortions were positive for antiprethrombin-1 antibody, but only 1 was positive for antifragment-1 antibody. The mean (+/- SD) titer of antiprethrombin-1 antibodies in patients with spontaneous abortion (36 +/- 9 U) was higher than that in women with normal pregnancies (10 +/- 4 U; P < 0.01). Antiprethrombin-1 antibody was detected in only 2 women with severe preeclampsia, whereas all 10 women with antiprethrombin antibodies were positive for antifragment-1 antibody. The antifragment-1 antibody titer in patients with severe preeclampsia (49 +/- 15 U) was higher than in women with normal pregnancies (13 +/- 6 U, P < 0.01).

CONCLUSIONS

There is a strong and specific association between various types of antiprothrombin antibodies with severe preeclampsia and spontaneous abortion.

Interleukin-3 and human trophoblast: in vitro explanations for the effect of interleukin in patients with antiphospholipid antibody syndrome

OBJECTIVE

To examine the effect of interleukin (IL)-3 on in vitro trophoblast differentiation, hormone production, and invasiveness affected by antiphospholipid antibodies.

DESIGN

Primary cytotrophoblast cell cultures.

SETTING

Obstetrics and Gynecology Department of the Catholic University, Rome, Italy.

PATIENT(S)

Five normal pregnant women underwent uncomplicated vaginal delivery at 36 weeks of gestation.

INTERVENTION(S)

Immunoglobulin (Ig) G antibodies were isolated from the plasma of two patients with antiphospholipid syndrome and two normal control subjects with the use of protein-G Sepharose columns. Cytotrophoblast cells were dispersed in Ringer's bicarbonate buffer containing trypsin and DNAseI, filtered, and layered over a Percoll gradient in Hank's balanced salt solution.

MAIN OUTCOME MEASURE(S)

We investigated the effects of IL-3 and antiphospholipid antibodies on trophoblast cell invasiveness, differentiation, and hormone secretion.

RESULT(S)

IgG obtained from patients with antiphospholipid syndrome bound to trophoblast cells, with inhibitory effects on the cells' invasiveness, differentiation, and hCG secretion. IL-3 was able to restore in vitro placental functions.

CONCLUSION(S)

These results imply that IL-3 favorably affects human trophoblast implantation and development.

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

OBJECTIVE

To investigate the in vitro ability of antiphospholipid antibodies (aPL) to bind human trophoblast cells and to affect gonadotropin secretion and invasiveness.

METHODS

Antiphospholipid antibody IgG from women with recurrent miscarriages, beta2-glycoprotein I (beta2GPI)-independent IgG aPL human monoclonal antibody (mAb) (519), and IgM anti-beta2GPI human mAb (TMIG2) were investigated for their binding to trophoblasts cultured for various amounts of time, their ability to affect invasiveness of Matrigel-coated filters, and their release of human chorionic gonadotropin (hCG).

RESULTS

Polyclonal IgG aPL, as well as mAb 519 and TMIG2, bound to trophoblasts, the highest binding being found when cells displayed the greatest amount of syncytium formation. TM1G2 binding was found to be betaGPI dependent. Both polyclonal and monoclonal aPL, but not the controls, significantly reduced hCG release and Matrigel invasiveness.

CONCLUSION

These findings suggest that aPL recognition of both anionic PL and adhered beta2GPI on trophoblast cell structures might represent a potential pathogenetic mechanism for defective placentation in women with the antiphospholipid syndrome.

Effect of anticardiolipin antibodies on prolactin and insulin-like growth factor binding protein-1 production by human decidual cells

PROBLEM

The effect of anticardiolipin antibodies (ACAs) on basal- and growth factor-stimulated prolactin and insulin-like growth factor (IGF) binding protein (BP)-1 production by cultured human decidual cells was investigated.

METHOD OF THE STUDY

Decidual cells were cultured for 24, 48, or 96 hr in medium supplemented with 5% ACA-containing or 5% control serum and increasing concentrations of insulin (1-10 micrograms/mL) or IGF-1 (10-100 ng/mL).

RESULTS

No significant increase in prolactin production was observed after addition of increasing doses of insulin and IGF-I in the presence of ACA-containing serum, while a dose-dependent stimulation was seen with control serum. Time-dependent prolactin accumulation was also reduced when cells were cultured in the former conditions. IGF BP-1 release was not affected by insulin and IGF-I in the presence of both sera. However, lower IGF BP-1 levels and a less pronounced time-dependent accumulation were observed in the presence of ACA-positive serum.

CONCLUSIONS

Our data suggest that ACAs affect cellular transduction mechanisms regulating critical events, such as decidual cell differentiation. These cellular dysfunctions might be relevant in the induction of some obstetric disorders typical of this syndrome.

Low-molecular weight heparin restores in-vitro trophoblast invasiveness and differentiation in presence of immunoglobulin G fractions obtained from patients with antiphospholipid syndrome

The present study was designed to investigate the effects of immunoglobulin G obtained from patients with antiphospholipid syndrome (APS) on in-vitro models of trophoblast invasiveness and differentiation. We tested the binding of affinity-purified immunoglobulin G to human primary trophoblast cells. These antibodies affected the invasiveness and differentiation of cytotrophoblast cells after binding to the cell surface. In addition, we determined whether the drugs used to treat APS might be able to restore the trophoblast functions. Low-molecular weight heparin, in a dose-dependent manner, significantly reduced the immunoglobulin G binding to trophoblast cells and restored in-vitro placental invasiveness and differentiation. No effect was observed in the presence of acetylsalicylic acid. These observations may help in understanding the role of these treatments in women with APS.

Pregnancy complications in women with recurrent miscarriage associated with antiphospholipid antibodies treated with low dose aspirin and heparin

OBJECTIVE

To study the obstetric course of women with a history of recurrent miscarriage associated with antiphospholipid antibodies, lupus anticoagulant and anticardiolipin antibodies, treated with low dose aspirin and low dose heparin.

DESIGN

Prospective observational study.

SETTING

University based tertiary referral clinic.

POPULATION

One hundred and fifty pregnant women with a history of recurrent miscarriage associated with persistently positive tests for antiphospholipid antibodies.

METHODS

Lupus anticoagulant was detected using the dilute Russell's viper venom time together with a platelet neutralisation procedure. IgG and IgM anticardiolipin antibodies were detected using a standardised enzyme linked immunosorbent assay. An IgG anticardiolipin level > or = 5 per litre units and an IgM anticardiolipin level > or = 3 per litre units was considered positive. Aspirin (75 mg daily) was commenced at the time of a positive pregnancy test and heparin (5000 units subcutaneously 12 hourly, or enoxaparin 20 mg daily) was started when fetal heart activity was demonstrated on ultrasound. Treatment was stopped at the time of miscarriage or at 34 weeks of gestation.

RESULTS

One hundred and seven pregnancies (71%) resulted in a live birth. Forty-one pregnancies (27%) miscarried, the majority in the first trimester. One woman had a stillbirth, and one a premature baby who died in the neonatal period. One pregnancy was terminated for a fetal anomaly. Gestational hypertension complicated 17% (18/108) of ongoing pregnancies and antepartum haemorrhage 7% (8/108). Twenty-six babies (24%) were delivered before 37 weeks of gestation. Fifty women (46%) were delivered by caesarean section. The median birthweight of all live born infants was 3069 g (range 531-4300); however 15% (16/108) of the infants were small for gestational age.

CONCLUSION

Combination treatment with aspirin and heparin leads to a high live birth rate among women with recurrent miscarriage and antiphospholipid antibodies. However, successful pregnancies are prone to a high risk of complications during all trimesters. Close antenatal surveillance and planned delivery of these pregnancies in a unit with specialist obstetric and neonatal intensive care facilities are indicated.

Antiphospholipid antibodies inhibit prostaglandin release by decidual cells of early pregnancy: possible involvement of extracellular secretory phospholipase A2

OBJECTIVE

To investigate the effect of antiphospholipid antibodies on eicosanoid production by human decidual cells and the in vitro interaction between antiphospholipid antibodies and secretory phospholipase A2.

DESIGN

Cultures of human decidual cells from early pregnancy.

SETTING

All decidual specimens were obtained from the Obstetrics and Gynecology Department of the Catholic University, Rome, Italy.

PATIENT(S)

Patients were undergoing operative laparoscopy for extrauterine pregnancy, with a period of amenorrhea ranging from 6 to 9 weeks.

INTERVENTION(S)

Decidual samples were collected at laparoscopy by routine uterine curettage.

MAIN OUTCOME MEASURE(S)

Decidual cells were incubated with antiphospholipid antibodies, and eicosanoids (prostaglandin [PG] E2, PGF2alpha, and thromboxane B2) were assayed by RIA after 24 hours of culture. In vitro interactions between antiphospholipid antibodies and secretory phospholipase A2 were investigated with use of a modified ELISA for phospholipase A2.

RESULT(S)

Antiphospholipid antibodies reduced eicosanoid release from decidual cells in a dose-dependent fashion. In vitro assays showed that antiphospholipid antibodies bound secretory phospholipase A2 and that a competition occurred between antiphospholipid antibodies and secretory phospholipase A2 for the common substrate cardiolipin.

CONCLUSION(S)

In light of the critical role played by eicosanoids in decidual function, we suggest that an interaction between antiphospholipid antibodies and secretory phospholipase A2 occurring in vivo might impair important cellular communications at the decidual level in the antiphospholipid antibody syndrome.

Antiphospholipid antibodies and reproduction: the antiphospholipid antibody syndrome

In women who have a diagnosis of APS (both clinical and laboratory criteria) the chance for successful pregnancy is reduced. In these cases, treatment appears to be a clear option, particularly in the case of prior thromboembolic events. The current preference of treatment for women with RPL and aPL antibodies is subcutaneous heparin and aspirin. This treatment should begin with a positive pregnancy test and continue postpartum. It is unclear, at this time, what treatment, if any, is required for women who do not meet all the criteria for diagnosis of APS, but who are known to have aPL antibodies. In some cases, these women were tested because of a prior false-positive test for syphilis, with subsequent identification of aPL antibodies. More recently, women undergoing IVF were tested and found to have an increased incidence of aPL antibodies. It was suggested that aPL antibodies are associated with infertility and failure to implant. However, a summary of published reports indicate that positive aPL antibodies in patients undergoing IVF do not influence ongoing pregnancy rates. This subject, however, remains an area of active investigation because aPL antibodies were shown to interact with the syncytiotrophoblast and cytotrophoblast layers and could, theoretically, after implantation.

The role of placental trophoblast in the pathophysiology of the antiphospholipid antibody syndrome

PROBLEM

The antiphospholipid (aPL) antibody syndrome is characterized by severe pregnancy complications, the cause of which remains unknown. We hypothesized that the placental trophoblast is a target for aPLs.

METHOD OF STUDY

The effects of monoclonal aPLs on trophoblast function, including the invasion of JAR into matrigel-coated filters and the effects of annexin V expression on BeWo, were investigated using choriocarcinoma models.

RESULTS

aPLs against phosphatidylserine (PS) significantly (P < 0.001) decreased the migration of JAR across the membrane. In the annexin V studies, undifferentiated BeWo did not express surface annexin V. After differentiation, BeWo expressed surface annexin V, which was removed in the presence of aPLs, resulting in increased binding of prothrombin.

CONCLUSIONS

PS is expressed on the trophoblast surface during differentiation and invasion of extracellular matrix. Our data suggest that aPLs against PS can directly affect trophoblast function by limiting the depth of decidual invasion and by concurrently creating a procoagulant surface on trophoblast exposed to the maternal circulation.

Prevalence and biological effects of anti-trophoblast and anti-endothelial cell antibodies in patients with recurrent spontaneous abortions

PROBLEM

Trophoblasts and endothelial cells represent a potential target for antibodies in women with recurrent spontaneous abortions. These antibodies have been shown to be associated with anti-phospholipid antibodies. Are they also present in women with unexplained pregnancy losses in the absence of anti-phospholipid antibodies?

METHOD OF STUDY

The anti-trophoblast antibodies were tested by an immunofluorescence assay on cells purified from pooled first-trimester placentae, whereas the anti-endothelial cell antibodies were measured by enzyme-linked immunoadsorbent assay (ELISA) on cells isolated from the umbilical vein and were cultured to confluence. The cytotoxicity of trophoblasts was evaluated in a homologous system. The expression of adhesion molecules on endothelial cells was quantitated by ELISA using specific monoclonal antibodies, and the expression of tissue factor was quantitated by a chromogenic assay measuring the formation of factor Xa.

RESULTS AND CONCLUSIONS

Complement-fixing antibodies to trophoblast represent a better marker to discriminate patients with recurrent spontaneous abortions from controls and are cytotoxic for the target cells. Anti-endothelial antibodies are also present in these patients and exhibit pro-inflammatory and pro-coagulant activities.

Pathogenesis of the antiphospholipid antibody syndrome

Endothelial and/or platelet activation likely initiates thrombus formation. Whether antiphospholipid antibody (aPL) is an activator, a toxic response, or a protective response is not clear, nor is it certain whether aPL is germ-line encoded or antigen-driven. The pregnancy model is particularly informative. Alternative hypotheses about thrombogenicity which relegate aPL to the role of bystander have not yet been excluded.