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Abstract

Objectives Preeclampsia is a maternal vascular syndrome defined by hypertension and proteinuria after 20 weeks of gestation. Noggin is a secreted chemokine that bind to bone morphogenetic proteins (BMPs) and limits their activity by inhibiting their access to signaling receptors. The precise expression and localization of Noggin in human placenta is unknown. Methods The aim of this study was to investigate the expression and localization of the antagonist Noggin in normal placenta throughout gestation and to determine whether its expression changed in preeclamptic placenta. In addition, the effect of Noggin on the endothelial angiogenic profile was determined. Results Immunohistochemical staining revealed that Noggin is expressed and localized in the cytotrophoblast and syncytiotrophoblast. The expression of Noggin, at the protein level, was higher in preeclamptic tissues compared to normal placenta. Western blot analysis of Noggin demonstrated an increase in the expression throughout gestation. No significant difference was observed at the mRNA level by quantitative polymerase chain reaction between normal and preeclampsia. When Noggin was added to human umbilical vein endothelial cells (HUVECS), it induced the release of placenta growth factor (PlGF; p n = 4) as measured by ELISA. BMP4 promoted angiogenesis when HUVEC were grown on growth factor-reduced Matrigel which was not inhibited by Noggin, the latter by itself had no effect. Conclusions Human placenta expresses Noggin, which stimulates PlGF. Additional studies are needed to discover the role of Noggin in pregnancy. Disclosures W.Y. Abu Al-Kheir: None.