The interplay between immune system and microbiota in gynecological diseases: a narrative review.

OBJECTIVE: The vaginal microbiome is a dynamic environment, depending on the results of a complex interplay between microbiota and the host. In physiological conditions, Lactobacillus species are the most represented, regulating glycogen metabolism in order to maintain normal pH. Vaginal flora has been divided into five subtypes. Pattern recognition receptors are present on both squamous epithelial cells lining the vagina and columnar cells lining the upper female genital tract. They respond directly to bacterial product expressed by vaginal microbiome. The vagina contains different immune related cells and receptors which can recognize and react with the microbial environment. Altered microbiota and altered interplay between microbiota and immune system underlie several gynecologic diseases. MATERIALS AND METHODS: In this review, literature data related to vaginal microbiota, vaginal inflammation, immune system and menopause, preterm labor and miscarriage, were summarized. Relevant publications were retrieved from: PubMed, Medline, Scopus and Web of Science. RESULTS: The vaginal microbiome and the relationship with immune system has been analyzed in different gynecologic conditions. Menopause is associated to estrogen loss which causes vaginal atrophy, reduced abundance of Lactobacilli and increased amount of other bacterial species. Estrogens influence vaginal immunity through known and unknown mechanisms. In bacterial vaginosis (BV), due to many bacterial species, there has been found an inhibition of the chemotaxis and cytokine secretion. A decreased concentration of Lactobacilli seems to be playing a role in preterm labor as well as the increased levels of pro-inflammatory cytokines. Finally, the disequilibrium in the Th1/Th2 immune adaptive response, with a shift from Th2 to Th1, appears to be playing a role in miscarriage. CONCLUSIONS: The interplay between microbiota and the host closely involves the immune system. In particular, the vaginal microbiota is classically characterized by Lactobacilli even if vaginal microbiome of asymptomatic woman of reproductive age includes multiple aerobic and facultative or obligate anaerobic species. The role of microbiota and immune system in determining gynecological and obstetric events has been studied throughout recent years reaching new advancements. Therefore, additional studies are needed to better comprehend the complexity of the issue.

Recurrent miscarriage and fetal congenital malformations: Is there a neglected causal association?

OBJECTIVE: The aim of the present study is to investigate the correlation between pregnancies complicated by morphological or chromosomal fetal anomalies and an obstetric history of two or more pregnancy losses, analyzing the association with any maternal risk factor. STUDY DESIGN: Retrospective analysis of women who had access to the Day Hospital Clinic of Fondazione Policlinico Universitario A. Gemelli IRCCS in Rome from 2012 to 2018 for a pregnancy complicated by fetal malformation and/or abnormal karyotype, and who had an obstetric history of at least one pregnancy loss. Patients were divided into four groups depending on the number of miscarriages and the presence of a genetic anomaly: Group 0 included women with <2 miscarriages and fetal malformations, Group 1 included women with ≥2 miscarriages and fetal malformations, Group 2 included women with <2 abortion, fetal malformations and the presence of genetic anomalies; Group 3 included women with 2 ≥ abortions, fetal malformations and genetic anomalies. Statistical analysis was performed using the SAS v. 9.4 (SAS Institute Inc., Cary, NC, USA). RESULTS: A total of 466 patients were included in the present analysis. Out of these, 379 patients belonged to Group 0; 40 patients entered in Group 1; Group 2 included 42 patients, and 5 patients were part of Group 3. Pregnancies complicated by fetal congenital malformations in patients with two or more pregnancy losses were significantly associated with maternal trombophilic disease and previous birth defects. Recurrent miscarriage and fetal structural anomalies were also significantly correlated with advanced maternal age. CONCLUSIONS: An adequate periconceptional counseling regarding the risk of fetal congenital anomalies may be indicated in patients affected by thrombophilic disease, as well as in those of advanced maternal age and with a pregnancy history of fetal malformations. The screening for thrombophilia may be advisable in patients with an obstetric history of congenital birth defects.

Correction to: Recurrent pregnancy loss is associated to leaky gut: a novel pathogenic model of endometrium inflammation?

Following publication of the original article [1], the authors reported updated affiliations for five of the authors. The updated affiliations are shown below and reflected in the affiliation list of this Correction.

HLA-DR is aberrantly expressed at feto-maternal interface in pre-eclampsia.

In normal pregnancy, villous cytotrophoblast and syncytiotrophoblast do not express HLA Class I and Class II molecules, while invasive extravillous trophoblast only express class I HLA-C and the atypical class Ib antigens, HLA-G, -E and -F. Inadequate maternal tolerance of invasive trophoblast has been proposed as a possible immunologic trigger of poor trophoblast invasion and subsequent occurrence of pre-eclampsia. This study aimed to investigate possible aberrant expression of class II HLA-DR on placentae and syncytiotrophoblast-derived extracellular vesicles (STEVs), obtained by dual placental perfusion, from pre-eclampsia (n = 23) and normal pregnant (n = 14) women. Here we demonstrate that HLA-DR can be detected in syncytiotrophoblast from a significant proportion of pre-eclampsia but not control placentae. HLA-DR was also observed, by flow cytometry, on STEVs and associated with placental alkaline phosphatase to validate their placental origin. HLA-DR positive syncytiotrophoblast was detected in placental biopsies from pre-eclampsia but not normal control cases, using immunohistochemistry. The HLA may be fetal or maternal origin. In the latter case a possible mechanism of acquisition is trogocytosis.

Recurrent pregnancy loss is associated to leaky gut: a novel pathogenic model of endometrium inflammation?

BACKGROUND: Recurrent pregnancy loss (RPL) occurs in 3-5% in about 30% of cases no cause can be found. Women with RPL show higher prevalence of undiagnosed gut disorders. Furthermore, in endometrial tissues of RPL women, higher expression of pro-inflammatory cytokines and Nalp-3 inflammasome has been observed. Aim of this study was to investigate whether an abnormal gut permeability might occur in RPL women and allow passage into systemic circulation of pro-inflammatory molecules able to induce endometrial inflammation. METHODS: 70 women with idiopathic RPL and 30 healthy women were recruited at the Recurrent Pregnancy Loss Outpatient Unit of the Gemelli Hospital of Rome from March 2013 to February 2017. Enrolled women underwent 51Cr-ethylene-diamine-tetraacetic acid absorption test to evaluate intestinal permeability. Sera obtained from enrolled women were analysed for lipopolysaccharide (LPS) by ELISA. Anxiety and depression state were evaluated by administering STAI-Y and Zung-SDS tests, respectively. Of all recruited individuals, 35 women with idiopathic RPL and 20 healthy controls accepted to undergo diagnostic hysteroscopy and endometrial biopsy. Endometrial lysates were investigated for inflammasome Nalp-3 by Western blot analysis, and caspase-1, IL-1ß and IL-18 by ELISA, respectively. RESULTS: Higher prevalence of abnormal intestinal permeability (P < 0.0001), increased circulating levels of LPS (P < 0.05), anxiety (P < 0.05) and depression (P < 0.05) were observed in RLP women compared to controls. Endometrial expression of Nalp-3, caspase-1 and IL-1ß was significantly increased in RPL group (P < 0.0001; P < 0.05 and P < 0.001, respectively). IL-18 endometrial levels were not found to be higher in RPL cases. Statistically significant association between higher intestinal permeability and abnormally increased expression of endometrial Nalp-3, was observed in RPL (P < 0.01). Furthermore, higher LPS serum levels, a bacterial-derived activator of Nalp-3 complex, was shown to be statistically associated to abnormal endometrial expression of Nalp-3 inflammasome (P < 0.01) in RPL women. CONCLUSIONS: In women with RLP, leaky gut might occur and allow passage into circulation of immune triggers, potentially able to elicit endometrial innate immune response and, thus, to contribute to miscarriage pathogenesis. Diagnosis and treatment of intestinal disorders underlying leaky gut might improve endometrial environment and pregnancy outcome.

Non-hormonal treatment of vulvo-vaginal atrophy-related symptoms in post-menopausal women.

In post-menopausal period vulvo-vaginal atrophy (VVA)-related symptoms may seriously affect women's quality of life. Hormonal replacement therapy effectively relieves these symptoms but it is not always safe or accepted, and a non-hormonal treatment is often needed instead. Over a period of 12 weeks, we tested the effect of a twice-a-week vulvo-vaginal application of a hyaluronic acid, AC collagen, isoflavones and vitamins-based cream (Perilei Pausa) on 35 women in post-menopausal period, reporting VVA-related symptoms. After 12 weeks of treatment with Perilei Pausa a significant improvement in vaginal dryness, vulvo-vaginal itching, dyspareunia (P < 0.001), dysuria (P = 0.02), nocturia (P = 0.009) and pollakiuria (P = 0.005) was reported by the women. Colposcopical score assessing the intensity of atrophic colpitis, cervico-vaginal paleness and petechiae was also reduced (P = 0.037, P = 0.016 and P = 0.032, respectively). No significant difference in terms of maturation value of cervico-vaginal epithelium was observed. In conclusion, Perilei Pausa may represent an effective and safe alternative treatment of symptomatic VVA in post-menopausal women.

Alterations of maternal plasma HTRA1 level in preeclampsia complicated by IUGR.

We evaluated the presence of HtrA1 in maternal plasma of normal pregnancies and of pregnancies complicated by preeclampsia (PE) without and with Intrauterine Growth Restriction (IUGR). We demonstrate that HtrA1 maternal plasma levels show significant different concentrations in first, second and third trimester of gestation and that HtrA1 concentration increases in maternal plasma of gestations complicated by PE with IUGR compared with control maternal plasma matched for gestational age. Based on these data high maternal plasma levels of HtrA1 could be considered as a possible marker of an occurring IUGR in preeclamptic women.

Effect of pravastatin on endothelial function and endothelial progenitor cells in healthy postmenopausal women.

PURPOSE: Coronary heart disease is the leading cause of morbidity and mortality in postmenopausal women. Among statins, pravastatin has been shown to significantly reduce fatal and non-fatal cardiovascular events in primary and secondary prevention trials. The aim of the present research was to investigate whether treatment with pravastatin can modify some indices of cardiovascular risk in healthy postmenopausal women such as significant reductions in total and LDL cholesterol and triglyceride levels. METHODS: 20 patients were randomized in double-blind fashion to treatment for eight weeks with either pravastatin 40 mg/day or placebo, and subsequently, after one-week wash-out, crossed-over to the alternative treatment (placebo or pravastatin) for the following eight weeks. We performed clinical and laboratory investigations, before and at the end of each treatment period, to evaluate patient response to the treatment with pravastatin. RESULTS: After eight weeks pravastatin therapy reduced the median low density lipoprotein (LDL) and total cholesterol (p < 0.01 in both cases). In contrast, insulin level and insulin sensitivity did not show any difference with regard to values observed after placebo treatment. The absolute number of endothelial progenitor cells-colony forming unit (EPC-CFU) was significantly increased by pravastatin treatment (30.6% increase, p < 0.05) and the number of senescent cells was significantly decreased. However pravastatin did not increase tube-like formation by EPC and did not improve endothelial function. CONCLUSIONS: Despite beneficial effect on lipids and EPC, short term pravastatin does not seem to improve other cardiovascular risk factors, at least in healthy postmenopausal women.

Anti-phospholipid antibody mediated fetal loss: still an open question from a pathogenic point of view.

Antiphospholipid antibodies (aPL) are associated with recurrent miscarriages and pregnancy complications, however their pathogenic mechanisms are still matter of research. Thrombotic events at the placental level cannot explain all of the clinical manifestations. It has been suggested that aPL may be responsible for a local acute inflammatory response mediated by complement activation and neutrophil infiltration eventually leading to fetal loss. However histological and immunohistological studies on human placental samples do support such a mechanism only in part and with no any clear relationship with the pregnancy outcome. A direct effect of aPL on both maternal and fetal placental tissues has been reported through the reactivity of the antibodies with beta2 glycoprotein I (beta2GPI) expressed on the cell membranes. These events do not require an inflammatory response and can be in part related to the inhibition of growth factors favouring a physiological placentation. Understanding the different pathogenic mechanisms of aPL-associated miscarriages may help in improving our therapeutic approach particularly in recurrent cases not responsive to the usual treatment.

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.

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.

Pathogenic role of anti-beta2-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.

Pathogenic role of anti-beta 2-glycoprotein I antibodies in antiphospholipid associated fetal loss: characterisation of beta 2-glycoprotein I binding to trophoblast cells and functional effects of anti-beta 2-glycoprotein I antibodies in vitro.

BACKGROUND: Antiphospholipid antibodies reacting with beta2-glycoprotein I (beta 2GPI) have been associated with recurrent fetal loss and pregnancy complications. OBJECTIVE: To investigate whether specific mutations in the phospholipid binding site of beta 2GPI might affect its binding to trophoblast and in turn the anti-beta 2GPI antibody induced functional effects. METHODS: beta 2GPI adhesion to trophoblast was evaluated as human monoclonal IgM or polyclonal IgG anti-beta 2GPI antibody binding to trophoblast monolayers cultured (1) in complete medium; (2) in serum-free medium; (3) after serum starvation in the presence of purified human beta 2GPI; or (4) in the presence of beta 2GPI with single or multiple mutations in the amino acid loop Cys(281)-Lys-Asn-Lys-Glu-Lys-Lys-Cys(288). The effect of anti-beta 2GPI binding to trophoblast was evaluated as chorionic gonadotropin (hCG) mRNA expression, and protein release by RT-PCR and radioimmunoassay, respectively. RESULTS: beta 2GPI adhesion to trophoblast and its consequent recognition by the specific antibodies were inversely proportional to the mutation number in the phospholipid binding site. Anti-beta 2GPI antibodies reduced gonadotropin release, hormone dependent hCG mRNA expression, and protein synthesis in the presence of beta 2GPI, while the addition of the mutants or the absence of beta 2GPI had no effect. CONCLUSIONS: beta 2GPI binds to trophoblast in vitro through its fifth domain, as reported for endothelial cells, and can be recognised by anti-beta 2GPI antibodies; the antibody binding downregulates trophoblast hCG synthesis and secretion. Such a mechanism might contribute to defective placentation in women with fetal loss associated with the antiphospholipid syndrome.

Antiphospholipid antibodies as cause of pregnancy loss.

Antiphospholipid antibodies detected by lupus anticoagulant, anticardiolipin or anti-beta2 glycoprotein I assays were associated with fetal loss. Rather than being diagnostic tools only, antiphospholipid antibodies are thought to be pathogenic. The strongest demonstration of their pathogenic role lies in the ability to induce fetal resorptions--the experimental equivalents of the human fetal losses--when passively infused in pregnant naive animals. However, still debated is how the antibodies might induce the obstetrical manifestations. Thrombotic events at the placental levels might be related to endothelial cell activation, inhibition of protein C/S system and fibrinolysis as well as to Annexin V displacement. However, the thrombophilic state apparently cannot explain all the miscarriages and a direct antibody-mediated damage on the trophoblast has been suggested. During differentiation to syncytium, trophoblasts express cell membrane anionic phospholipids that can bind beta2 glycoprotein I, the main cationic phospholipid binding protein recognized by the antiphospholipid antibodies. Adhered beta2-glycoprotein I might be recognized by the antibodies that, once bound, strongly interfere with in vitro trophoblast cell maturation so resulting in a defective placentation. These mechanisms have been suggested to play a role in early fetal loss, while thrombotic events would be responsible for miscarriages late in the pregnancy.

Effect of folic acid on homocysteine-induced trophoblast apoptosis.

In trophoblast cells exposed to homocysteine (Hcy) we observed cellular apoptosis and the inhibition of trophoblast functions. Because folate and Hcy, linked in the same metabolic pathway, are inversely related, we investigated the role of folic acid in reversing the Hcy effect in human placenta. In primary trophoblast cells we examined the cytosolic release of cytochrome c, both M30 and terminal deoxynucleotidyl transferase-mediated dUDP nick-end labelling (TUNEL) and DNA laddering. Hcy (20 micromol/l) treatment resulted in cytochrome c release from mitochondria to the cytosol, and an increased number of M30-positive trophoblast cells and TUNEL positive nuclei. Furthermore, DNA cleavage in agarose gel and the determination of histone-associated DNA fragments have been investigated. Homocysteine induced DNA fragmentation and significantly reduced hCG secretion. The addition of folic acid (20 nmol/l) resulted in inhibition of the effects of Hcy on human trophoblast. These results suggest a protective role of folic acid in the prevention of trophoblast apoptosis linked to Hcy.

Monoclonal anti-annexin V antibody inhibits trophoblast gonadotropin secretion and induces syncytiotrophoblast apoptosis.

The pathogenic role of anti-annexin V antibodies remains unclear. Anti-annexin V antibodies are frequently associated with higher incidences of intrauterine fetal loss, preeclampsia, and arterial and venous thrombosis. The present study investigated the in vitro ability of anti-annexin V antibody to bind human trophoblast cells, to affect trophoblast gonadotropin secretion and invasiveness, and to induce placental apoptosis. Cytotrophoblast cells were dispersed in Ringer bicarbonate buffer containing trypsin and DNase I, filtered, and layered over a Percoll gradient in Hanks balanced salt solution. In the case of monoclonal anti-annexin V antibody, the highest binding was found when the cells displayed the greatest amount of syncytium formation. Anti-annexin V antibody, but not its negative control, induced trophoblast apoptosis and significantly reduced trophoblast gonadotropin secretion. These findings suggest that recognition by anti-annexin V antibody of adhered annexin V on trophoblast cell structures might represent a potential pathogenic mechanism by which these antibodies can cause defective placentation.

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.

Antiphospholipid antibodies in obstetrics: new complexities and sites of action.

The antiphospholipid syndrome, the cause of which remains unknown, is characterized by severe pregnancy complications. Fetal losses have been attributed to thrombosis of the uteroplacental vasculature and placental infarction. Polyclonal and monoclonal antiphospholipid antibodies seem able to recognize a 'plasma cofactor' on the endothelial and trophoblast cell surfaces and to affect cell function, inducing a procoagulant state. Although thrombosis is observed frequently in the decidua and placentas of patients with antiphospholipid antibodies, this observation was not universal, nor present in a sufficient degree to account for the pregnancy loss associated with this syndrome. Recent observations have suggested that antiphospholipid antibodies decreased placental hormone production and trophoblast intercellular fusion and invasion, suggesting that many of the obstetric complications observed in the syndrome may be due to antiphospholipid antibody-induced trophoblast dysfunction. However, the complex antigens on the trophoblast surfaces are still to be characterized and correlated with clinical manifestation. It is clear that successful pregnancies with the syndrome are more likely to occur after maternal treatment. Although prednisone may still be needed to treat manifestations associated with autoimmune disorders, the use of heparin, together with low-dose aspirin, has replaced prednisone for treatment of pregnant women. Maternal treatment and careful monitoring of fetal well-being are mandatory in the management of these high-risk pregnancies.

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.