Characteristics of hematopoietic stem cells of umbilical cord blood

Anna Hordyjewska 0 1 ukasz Popioek 0 1 Anna Horecka 0 1 0 . Popioek (&) Department of Organic Chemistry, Medical Univeristy of Lublin , Chodz ki 4A Street, 20-093 Lublin , Poland 1 A. Hordyjewska A. Horecka Department of Medical Chemistry, Medical Univeristy of Lublin , Lublin , Poland Umbilical cord blood collected from the postpartum placenta and cord is a rich source of hematopoietic stem cells (HSCs) and is an alternative to bone marrow transplantation. In this review we wanted to describe the differences (in phenotype, cytokine production, quantity and quality of cells) between stem cells from umbilical cord blood, bone marrow and peripheral blood. HSCs present in cord blood are more primitive than their counterparts in bone marrow or peripheral blood, and have several advantages including high proliferation. With using proper cytokine combination, HSCs can be effectively developed into different cell lines. This process is used in medicine, especially in hematology. - Blastomeres are the first stem cells in the development of the human body. These cells have the ability to develop into any cell type of the body, so-called totipotency. In a further development of the embryogastrulation stage, cells lose their properties of totipotency and begin the speciation process. When the embryo develops to the stage of gastrula two types of cells are formed: the throphoblast and embryonic node. Cells present in the embryonic node are called pluripotent cellsthey have the ability to transform into all types of cells derived from the ecto-, mesoand endoderm. After moving to the uterus, these cells cannot differentiate into germ cells in the placenta and the surrounding tissue (Stec et al. 2003). In the further stages, pluripotent cells are transformed into tissue stem cells, so-called multipotent cells. These cells are subdivided into two progenies: one parent stem cell and one daughter cell, which has unipotent activity. The development process of stem cells is most readily observed in the hematopoietic system (Fig. 1) (Jo siak et al. 2004). All blood cell elements have their origin in a small population of hematopoietic stem cells, that have the ability to self-replicate, self-renew and to differentiate into specific cell lines (Yao et al. 2004). Fetal hematopoiesis starts at about 23 weeks after fertilization and, initially, takes place in the yolk-sac. During fetal life, hematopoiesis gradually moves to the liver, and then after the development of the bones, at about 56 weeks takes place in the bone marrow (Czajka et al. 1999; Jedrasiak et al. 1999). A multipotential hematopoietic stem cell (HSC) during whole life divides asynchronously into two daughter cells Totipotent stem cell blastomere Pluripotent stem cells - embryonic node (ectoderm, mesoderm, endoderm) Multipotent stem cell - "tissue stem cell" (e.g.: hematopoietic stem cells, HSCs) Multipotent stem cell e.g.: (HSC) "reserve" Precursor of myeloid cell Precursor of lymphoid cell (e.g.: erythrocyte, thrombocyte, macrophage) (T and B lymphocytes, NK cells) one HSC and one hematopoietic progenitor cell (HPC). HPC is the earliest progenitor cell, which, unlike the HSC, does not have the capacity to selfrenew and is limited to one or more extra lines of differentiation (Kucia and Drukaa 2002) where there is no return, and is removed during programmed cell death (Dabrowski 1998a; Grskovic et al. 2004). HPC may give rise to myelocytic precursor colony forming unit of granulocyte, erythroid, macrophage and megakaryocyte (CFU-GEMM) or lymphoid precursor (CFU-Lymph). The targeted cells defined by some authors as colony forming cells (CFC) originate from CFU-GEMM or CFU-Lymph (Jedrasiak et al. 1999). Colony forming unit of granulocyte, erythroid, macrophage and megakaryocyte gives rise to cells such as: colony forming unit of erythroid (CFU-E), colony forming unit of megakaryocytes (CFU-Meg), colony forming unit of granulocytes and macrophages (CFU-GM), colony forming unit of eosinocytes, colony forming unit of basophiles, colony forming unit of mastocyte, form which the erythrocytes, platelets, neutrophils, monocytes, macrophages, eosinophils, basophils, and the mast cells are generated, respectively. B cells, NK cells and precursors of thymocytes are formed from lymphoid precursor (Dabrowski 1998a). The morphology of cord blood hematopoietic cells The morphology of human HSC is similar in appearance to a small cell with a narrow hem cytoplasm, in which mitochondria and endoplasmic reticulum are poorly marked (Kopec-Szlezak and Podstawka 2001). It has the ability to intense proliferation and selfrenewal and the ability to multi-line differentiation (Belvedere et al. 1999; Brunet de la Grange et al. 2002; Summers et al. 2001; Thierry et al. 1992). HSC is maintained in the G0 phase of the cell cycle, does not exhibit metabolic activity and has almost totally inhibited protein synthesis (Machalinski et al. 1998), thereby it is slightly stained with fluorescent dyes, such as Rhodamine 123, Hochest 33342, or Pyronin Y (Dravid and Rao 2002; Machalinski et al. 1997; Machalin ski and Ratajczak 1997; Machalinski et al. 1998). Activation of hematopoietic cells is combined with its output from G0 phase to G1 phase, which is characterized by increase of transcription and mRNA accumulation. Cells derived from long-term cultures have similar morphology: they are large and round, with large and round nucleus, have a small amount of cytoplasm, which is also characteristic for HPC progenitor cells (Tian et al. 2005). Surface markers expressing on cord blood hematopoietic cells For several years, the surface markerCD34 antigen, was only used to determine the hematopoietic cells. Nevertheless, most cells with CD34 antigen expression of bone marrow or umbilical cord blood, have other antigenic determinants. The immunophenotype of stem cells/progenitors can be assessed using: the cytometric analysis of the presence of CD34/ CD38 proteoglycan analysis of the marker of mature line (HLA-DR) analysis of c-kit tyrosine kinase receptor and their respective labeling with the antibodies conjugated to fluorochromes (Stojko and Witek 2005). As it is mentioned above, a characteristic feature of hematopoietic stem and progenitor cells is the presence of CD34 antigen. It is a transmembrane glycoprotein of approximately 104120 kDa, which belongs to the adhesion molecules known as sialomucines. It is composed of a protein core of 40 kDa containing 6 to 9 N-binding sites of glycosylation and more than 9 O-binding sites of glycosylation (Tarach 1999). The cytoplasmic part of CD34 antigen has two sites for the phosphorylation of protein kinase C, and one site for tyrosine phosphorylation. Therefore its function is associated with the occurrence of transmembrane signalling (Tarach 1999). CD34 antigen is involved in the regulation of hematopoietic stem cells adhesion to the stroma (Gutierrez-Rodriguez et al. 2000; Kopec-Szlezak and Podstawka 2001). (...truncated)