N. Di Simone

Antiphospholipid antibodies affect trophoblast gonadotropin secretion and invasiveness by binding directly and through adhered β2‐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 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 b2-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.

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.

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

Our objective was to evaluate whether antiphospholipid antibody-containing sera could play a regulatory role in signal transduction induced by gonadotrophin releasing hormone (GnRH) when incubated with normal human trophoblast cells. To test this hypothesis we established an in vitro placental culture system in which GnRH addition in the presence of normal human serum resulted in a significant increase in human chorionic gonadotrophin (hCG) secretion. When GnRH was added to the culture medium with antiphospholipid antibody-containing sera, the hCG increase was inhibited. These results suggest the possibility that antiphospholipid antibody-positive sera can exert their effect on GnRH-induced signal transduction. Further studies are needed to explain their exact site of action.

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 (β2GPI) 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. Lupus (2010) 19, 453—456.

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.

Insulin secretion in patients with gestational diabetes : relationship with pregnancy outcome

The authors observed that there is wide variability in insulin response to an oral glucose tolerance test in women developing carbohydrate intolerance during pregnancy. This variability ranges from a reduction of pancreatic islet function to a normal or exaggerated secretory pattern of insulin. Moreover the results also suggest that exaggerated insulin secretion and/or high insulin resistance may play a role in the regulation of gestational blood pressure and that a higher glucose/insulin ratio may be positively related to birth weight. Clearly, further studies are needed to investigate the impact of this metabolic situation on the optimization of the clinical control of glucose metabolism and fetal homeostasis.

In vitro human growth hormone increases human chorionic gonadotropin and progesterone secretion by human placenta at term: evidence of a modulatory role by opioids.

We examined the in vitro effect of human growth hormone (hGH) on hormone placental production and the modulation by opioids of this function. Small placental fragments from 12 term placentas were incubated at 37 degrees C in a 95% air and 5% CO2 atmosphere for 4 h with various concentrations of hGH (1-1000 ng/ml) or naloxone (3-500 ng/ml). Both hGH and naloxone increased the concentrations of human chorionic gonadotropin (hCG) and progesterone in the media. The effect of the hGH was dose-dependent and statistically significant at 10 ng/ml, while naloxone was able to increase hCG and progesterone production only at the highest doses (250-500 ng/ml). The concomitant treatment with ineffective doses of naloxone and hGH was able to enhance hCG and progesterone secretion reaching levels similar to those obtained with the highest doses of hGH alone. High naloxone concentrations significantly decreased both hCG and progesterone secretion induced by high doses of hGH. This study confirms the relevance of growth hormone in sustaining placental endocrine activities and indicates an effect of opioids in modulating these functions.

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 womens 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.

Insulin plasma levels in pregnant patients with impaired glucose tolerance : Relationship with pregnancy outcome

To investigate the impact of insulin secretion on pregnancy outcome, we studied 102 patients at risk for glucose intolerance between 28 and 34 weeks of gestation. All patients had a 3-hour oral glucose tolerance test (OGTT, 100 g glucose), and glucose and insulin plasma levels were assayed: 32 patients had a gestational diabetes (GDM); 25 had an impaired gestational glycemic tolerance (IGGT), and 45 with normal OGTT constituted the control group. No significant difference between groups was seen for pregnancy outcome. Based on the mean +/- 2 SD of insulin secretion of the control group, IGGT/GDM patients were classified as normoinsulinemic (34 patients), hyperinsulinemic (17 patients), or hypoinsulinemic (6 patients). The hyperinsulinemic IGGT/ GDM group showed a greater incidence of pregnancy-induced hypertension (p < 0.03), while the percentile birth weight was significantly lower (p < 0.01) with respect to normo-hypoinsulinemic patients. Moreover a higher glucose/ insulin ratio was significantly related to birth weight (p < 0.01). Our results suggest an impact of insulin secretion on pregnancy outcome and support the importance of determining the insulinemic pattern in pregnant patients at risk for glucose intolerance.