Hypoxia changes the coagulation capacities of syncytiotrophoblast microparticles (STBM)

s / Placenta 35 (2014) A1eA112 A86 Results: Histological abnormalities of the three villi populations were observed in the normotensive, mild, moderate and severe hypertensive groups. The occurrence of syncytial knots were observed more frequently in the severely hypertensive than the normotensive group and the moderately hypertensive groups. Fibrinoid necrosis of villi occurred in all villous types in the normotensive group as well as in the hypertensive groups. These areas appeared acidophilic, showing strongly PAS positive necrotic areas of the placental stromal tissue. Complete necrosis of villous stroma was also observed. Hypovascular villi were occasionally observed in all study groups. Thickening of the trophoblast basement membrane was observed in 9 cases of the severely hypertensive group. A semiquantitative increase in the number of villous cytotrophoblast cells were noted in the severely hypertensive group compared to the normotensive group. A nuclear thinned-out area of villous syncytium bulging over the surface of stromal capillaries into the intervillous space was observed in all study groups. Discussion: The histopathological features noted are consistent with hypoxia which emanates from the defective placentation associated with the lack of transformation of the spiral arteries in pre-eclampsia. P2.78-N. HYPOXIA CHANGES THE COAGULATION CAPACITIES OF SYNCYTIOTRO PHOBLAST MICROPARTICLES (STBM) Claudia Gohner , Carolin Bonnke , Maik Sossdorf , Wolfgang L€ osche , Dionne S. Tannetta , Sicco Scherjon , Udo R. Markert , Ekkehard Schleusner , Justine S. Fitzgerald a Placenta-Lab, Clinic for obstetrics and gynecology, Jena University Hospital, Jena, Thuringia, Germany; Department of Anesthesiology and Intensive Care Medicine, Jena University Hospital, Jena, Thuringia, Germany; Department Obstetrics and Gynaecology, University Medical Center Groningen, Groningen, The Netherlands; Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Oxford, UK Introduction: Severe forms of the pregnancy-associated disease preeclampsia (PE) are linked to endothelial dysfunction as well as the release of syncytiotrophoblast microparticles (STBMS) into the maternal circulation. STBMsareknowntoexpress tissue factorand trigger inflammatoryprocesses on the endothelium, however their coagulant capacities are not well characterized. Our goalwas to analyze the thrombogenic potential of STBMs. Methods: Ex vivo placenta perfusion (normoxic standard-perfusion versus maternal-single-sided hypoxic perfusion) provided samples enriched with placental factors. Successive ultra-centrifugation yielded samples either without cell debris, without STBMs or without exosomes. STBMs were quantified with our in-house ELSA. Their impact on thrombin formation was analyzed using a commercial microparticle/phosphatidyl-serinedependent ELISA (Hyphen Biomed). Maximum platelet aggregation and rate were investigated via aggregometer in platelet rich plasma in presence/absence of placental samples (PAP-4 Aggregometer, m€ olab GmbH, Hilden). Results: STBM concentrations and placental perfusate-triggered thrombin formation remained stable under normoxia, but increased under hypoxia. Hypoxia-altered perfusates elevated thrombin formation independent of STBM concentration, while the exclusion of STBMs from perfusates led to a significantly reduced thrombin formation. In comparison to control (oxygenated perfusion medium), normoxia perfusates induced stable, low maximum platelet aggregation with highly variable aggregation rates. Under hypoxia, maximum platelet aggregation was highly variable, while rates remained constant. Again, exclusion of STBMs from perfusates resulted in normalization of mentioned aggregation characteristics to control levels. Conclusion: The observed coagulant capacities of placental samples can now be affiliated to STBMs, and to a minor part to placental exosomes. STBMs expose negatively-charged phosphatidyl-serines, which mediated some of the observed thrombogenic alterations. These effects seem to be dose-independent and caused instead by modifications in phenotype. The hypoxic STBM-phenotype seems to deregulate coagulatory functions. The apparent thrombogenic protection mediated by the normoxic phenotype was unexpected. This puts STBM functions in a new perspective, especially regarding the course of PE. P2.79-N. HO-1 EXPRESSION IS NOT REDUCED IN PREECLAMPTIC PLACENTA, AND DOES NOT REGULATE SFLT-1 OR SOLUBLE ENDOGLIN SECRETION IN EITHER PRIMARY TROPHOBLAST OR ENDOTHELIAL CELLS Tu'uhevaha Kaitu'u-Lino , Kenji Onda , Sally Beard , Fiona Brownfoot , Cathy Cluver , Laura Tuohey , Clare Whitehead , Stephen Tong , Natalie Hannan a a Translational Obstetrics Group, Department of Obstetrics and Gynaecology, Mercy Hospital for Women, University of Melbourne, Heidelberg, Australia; Department of Clinical Pharmacology, TokyoUniversityof Pharmacyand Life Sciences, School of Pharmacy, Tokyo, Japan Background: It is widely accepted that preeclampsia (PE) is associated with decreased placental heme oxygenase-1 (HO-1; antioxidant enzyme) expression [1, 2]. Furthermore, it has been reported that decreased HO-1 expression increases soluble fms-like tyrosine kinase-1 (sFlt1) and soluble endoglin (sEng) secretion. These observations have prompted the field to identify drugs that induce HO-1 as an approach to treat PE. However, the link between HO-1 and PE or sFlt1/sEng production has not been validated. Methods: Placental tissue was obtained from pregnancies complicated by severe PE (<34 weeks gestation; n1⁄418) and gestationally-matched normotensive controls (n1⁄427), and HO-1 measured. We also performed a meta-analysis of publically available microarray data (5 independent studies) to further examine HO-1 expression in PE placenta. Functionally, we induced (using small molecules) and silenced HO-1 (using siRNAs) in primary human trophoblast and human umbilical vein endothelial cells (HUVEC), and measured sFlt-1 and sEng secretion. Results: There was no significant difference in HO-1 mRNA or protein levels between PE and control placentas. Our analysis of published microarray data failed to find evidence that HO-1 is differentially expressed with PE. Silencing HO-1 and Nrf2 (nuclear factor erythroid-2related factor 2, transcription factor upstream of HO-1) did not alter sFlt1 or sEng secretion, in either primary trophoblast or HUVECs. While Polaprezinc and BG-12 upregulated HO-1 expression, this did not affect sFlt-1 or sEng production. Conclusion: HO-1 expression is not reduced in severe PE placenta. Furthermore, experimental induction or silencing of HO-1 expression did not alter sFlt1 or sEng levels. Thus, we were unable to verify the premise that HO-1 is reduced in PE and plays a major molecular role in sFlt1 or sEng regulation. 1 Cudmore et al., Circulation 2007:115(13);1789-97 2 Levytska K et al., Placenta 2013;34(4):291-8. P2.80-N. PROTON PUMP INHIBITORS SIGNIFICANTLY QUENCH PATHOPHYSIO LOGICAL CHARACTERISTICS OF PREECLAMPSIA IN PRIMARY PLACENTAL AND ENDOTHELIAL MODELS: A NOVEL CANDIDATE THERAPEUTIC Kenji Onda , Tu'uhevaha Kaitu'u-Lino , Sally Beard , Natalie Binder , Laura Tuohey , Roxanne Hastie , Fiona Brownfoot , Stephen Tong , Natalie Hannan a a Translational Obstetrics Group, Department of Obstetrics and Gynaecology, Mercy Hospital for Women, University of Melbourne, Melbourne (Heidelberg), Australia; Department of Clinical Pharmacology, Tokyo University of Pharmacy and Life Sciences, School of Pharmacy, Tokyo, Japan Background: Preeclampsia (PE) is a serious complication of pregnancy. The key pathophysiological aspects are 1) oxidative stress 2) release of the anti-angiogenic factors sFlt1 and sEng and 3) maternal endothelial dysfunction. A drug that counters these effects could be effective in treating preeclampsia. Objective: To examine the potential of proton pump inhibitors as a preeclampsia therapeutic. Methods: We performed functional studies on three tissue types; 1) primary trophoblast 2) human umbilical vein endothelial cells (HUVEC) and 3) uterine microvascular cells. We examined the effects of five PPIs at