We have investigated the characteristics of human hematopoietic progenitor cells (HPCs) with the CD34+CD45lowSSClow phenotype from full-term placental tissue (FTPT) as compared to cord blood (CB) and fetal liver (FL) cells. We demonstrated the presence of cell subpopulations at various stages of the differentiation with such immunophenotypes as CD34+/lowCD45low/−, CD34++CD45low/−, CD34+++CD45low/−, CD34+/lowCD45hi, and CD34++CD45hi in both first trimester placental tissue (FiTPT) and FTPT which implies their higher phenotypic heterogeneity compared to CB. HPCs of the FTPT origin expressed the CD90 antigen at a higher level compared to its expression by the CB HPCs and the CD133 antigen expression being at the same level in both cases. The HPCs compartment of FTPT versus CB contained higher number of myeloid and erythroid committed cells but lower number of myeloid and lymphoid ones compared to FL HPCs. HPCs of the FTPT and CB origin possess similar potentials for the multilineage differentiation in vitro and similar ratios of myeloid and erythroid progenitors among the committed cells. This observation suggests that the active hematopoiesis occurs in the FTPT. We obtained viable HPCs from cryopreserved placental tissue fragments allowing us to develop procedures for banking and testing of placenta-derived HPCs for clinical use.

The purpose of this study was to investigate the immunophenotypes and gene expression profile of high proliferative placenta-derived multipotent cells (PDMCs) population at different stages of culture. We demonstrated that the colonies resulting from single cells were either positive or negative for CK7, whereas only PDMC clones with weak CK7 expression (CK7low-clones) were highly proliferative. Interestingly, vimentin positive (Vim+) placental stromal mesenchymal cells did not express CK7 in situ, but double CK7+Vim+ cells detection in tissue explants and explants outgrowth indicated CK7 inducible expression in vitro. PCNA presence in CK7+Vim+ cells during placental explants culturing confirmed belonging of these cells to proliferative subpopulation. Transcription factors CDX2 and EOMES were expressed in both CK7low-clones and subset of stromal mesenchymal cells of first-trimester placental tissue in situ. Meanwhile, CK7low -clones and stromal mesenchymal cells of full-term placental tissue in situ expressed ERG heterogeneously. SPP1, COL2A1, and PPARG2 mesodermal-related genes expression by CK7low-clones additionally confirms their mesenchymal origin. Inherent stem cell-related gene expression (IFTM3, POU5F1, and VASA) in CK7low-clones might indicate their enrichment for progenitors. Finally, in CK7low-clones we observed expression of such trophoblast-associated genes as CGB types I and II, fusogenic ERVW-1, GCM1, and GATA3. Thus, our results indicate that PDMCs acquired the representative immunophenotype signature under culture conditions.

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Umbilical cord blood has been widely used to treat both malignant and non-malignant hematological diseases for over 30 years. During this time, more than 40,000 successful hematopoietic stem cell (HSC) transplantations of umbilical cord blood have been performed. However, today in Ukraine there is no public umbilical cord blood bank established for unrelated HSC transplantation to patients with oncohematological disorders (both children and adults). In this regard, the HSC units must be purchased abroad or the patients are sent to foreign clinics for high-cost treatment. The organization of a public umbilical cord blood bank in Ukraine would help in a short time to meet the needs of patients with oncohematological disorders for donor HSCs for unrelated transplantation and save significant funds for the treatment of patients abroad. According to the experience of the world's leading oncohematological centers, when it is impossible to find either a related or haploidentical donor or in all available registries – a unrelated transplant, the search continues in the registers of public cord blood banks and an umbilical cord blood unit that matches the criteria is usually found. The optimal choice of umbilical cord blood unit is crucial to maximize the likelihood of successful transplant engraftment and recipient survival after the transplantation, so the criteria for cord blood unit selection for unrelated transplantation are a bit broader than those used when matching donor-recipient pairs. The review presents the main criteria for cord blood unit selection according to the assessment of its quality, cell dose, HLA matching for unrelated transplantation to recipients of different age groups in accordance with international guidelines developed by the National Marrow Donor Program (NMDP), USA Center for International Blood and Brain Transplantation Research (CIBMTR), in collaboration with the NMDP Council Advisory Group, as well as in accordance with the American Society for Transplantation and Cellular Therapy (ASTCT) and the Seventh Edition of the NetCord-FACT International Standards for Cord Blood Collection, Banking, and Release for Administration.