PP044. Differential expression of trophoblast-, endothelial- and embryonic stem cell-associated transcription factors in 1st trimester, and in 3rd trimester preeclampsia and intrauterine growth restriction

Abstract

Trophoblast progenitor cells express stem cells markers (SCM) to maintain the proliferative characteristic of stem cells. Beyond blastocyst stage or in preeclampsia (PE) or intrauterine growth restriction (IUGR) little is known about expression of SCMs. We examined the expression of trophoblast and other SCMs in 1st and 3rd trimester placenta and in preeclampsia (PE) and intrauterine growth restriction (IUGR) in order to discriminate if these markers might be involved in progenitor cell functions. 8 samples each of 1st trimester placentae (elective abortions), 3rd trimester IUGR, PE and control (normal term pregnancy placentae) were stained by immunoperoxidase to detect the SCMs: CDX2 (trophectoderm SCM), SOX2, NANOG and OCT4A (embryonic SCMs) and NOTCH1 (endothelial SCM). In 1st trimester all SCM were detected, expressed homogenous in syncytio- and cytotrophoblast, and grow increasingly mosaic-like towards the end of 1st trimester. These signals are lost or diminished in 3rd trimester, whereby the syncytiotrophoblast loses these signals first. NOTCH1, however, remains highly expressed in all trophoblast subtypes of both IUGR and PE pregnancies. Both embryonic and trophoblast SCMs are expressed in 1st trimester trophoblast and appear most vivid among the villous trophoblast of very early pregnancy. Loss of stem cell transcription factor expression in term placentae indicates temporal regulation, and a so far unknown specific function.