Phenotypic heterogenecity of hematopoietic progenitor cells from placental tissue: comarative analysis with umbilical cord blood and fetal liver

The study of placental hematopoietic progenitor cells (HPCs) and comparison of their properties with other fetal and adult HPCs is necessary for assessing of their possible clinical application. It has been shown that HPCs from placenta are heterogeneous by phenotype: placental tissue contains three populations with different level of CD34 expression such as CD34+++CD45low/-, CD34++CD45low/- and CD34+/lowCD45low/-. Similar to fetal liver placenta contains both, population of CD34++CD45low/- and CD34+CD45low/-cells, suggesting hematopoiesis in placental tissue. CD34++CD45low/- population also expressed CD133, almost negative for lineage markers, and had lymphocyte-like morphology conforming the presence of primitive HPCs in this population. Additionally, we found later progenitors with phenotype CD34+/lowCD45+ in placental tissueas the majority of these cells expressed hematopoietic lineage markers. Population with phenotype CD34+++CD45low was observed in the placenta that may evidence for their generation in the placental tissue or migration from the other sites of hematopoiesis and changing phenotype under placental microenvironment.