s / Placenta 35 (2014) A1eA112 A93 Objectives: The Wharton’s jelly (WJ) of the umbilical cord is derived from the mesoderm of the primitive streak which invades the connecting stalk and primary chorionic villi. Mesenchymal stem cells in the mesoderm differentiate and participate in neo-vasculogenesis of the umbilical and placental circulation. Whether these cells have a continued role in placental/umbilical vascular growth and maturity is not known. Fetal stem cells have been shown to traffic and repair injured myocardial endothelium in mice (Kara et al. 2012). Their ability to interact with the uterine endothelium has not been investigated. The aim of this study was to investigate whether umbilical stem cells (WJMSC) can interact and influence umbilical vein and uterine endothelial monolayers. Methods: Human umbilical vein (HUVEC) and uterine microvascular endothelial cells (HUtMEC) were grown to 70% confluence in endothelial media and to full confluence in mixed media (endothelial: stem cell media). Isolated WJMSC, labelled with the fluorescent tracker, PKH26 was added on top. Cell-cell interactions were monitored with fluorescence time-lapse microscopy. Key events were analysed by confocal microscopy after vascular endothelial (VE) cadherin immunocytochemistry. Results: WJMSC displayed non-apoptotic blebbing, amoeboid movement and shedding of exosomes as early events. There was a time lag of 60 min before transmigration of WJMSC via the paracellular pathway to subendothelial positions. This was concomitant with disruption of VE-cadherin (statistically significant reduction of continuous junctional profiles). By 16h, a majority of WJMSC were resident underneath the endothelial monolayers; junctional profiles returned to normal values. At 22h, the cocultures showed a higher % of paracellular clefts with continuous VEcadherin labelling, indicative of increased junctional maturity. Conclusion: Our data suggests that umbilical mesenchymal stem cells can interact with and influence junctional organisation of both fetal and uterine endothelial cells. Their role, if any, in uterine vascular re-modelling during pregnancy requires investigation. P2.102-N. UMBILICAL CORD STEM CELLS INDUCE GLIAL FATE IN NEURAL PROGENITOR CELLS Byron Oppliger , Marianne J€ orger-Messerli , Camilla Marini , Ursula Reinhart , Daniel V. Surbek , Andreina Schoeberlein a Department of Obstetrics and Gynecology, University Hospital, Department of Clinical Research, University of Bern, Bern, Bern, Switzerland; Graduate School for Cellular and Biomedical Sciences (GCB), University of Bern, Bern, Bern,