Cord Blood Stem Cells

Several stem and progenitor cells (SPCs) have been identified in human umbilical cord blood (UCB), bringing these unique cells as an important target for multitude experimental and clinical studies. Cord blood represents not only a rich source of applicable hematopoietic stem cells (HSCs) involved in hematopoietic and immunological system reconstitution but also an important reservoir of heterogeneous fraction of non-HSCs that may be utilized in regeneration of other tissue types. Such primitive SPCs belonging to non-hematopoietic compartment of UCB have been already described by several investigators and may include: very small embryonic-like stem cells (VSELs), endothelial progenitor cells (EPC), human UCB-neural stem cells (HUCB-NSC), unrestricted somatic stem cells (USSC), mesenchymal stem cells (MSC), multilineage progenitor cells, and other progenitor fractions. In some cases, vast similarities observed between those populations may indicate their possible fenotypic and functional overlap. In fact, some of non-hematopoietic UCB-derived SPCs may represent related fractions of primitive cells, but identified by various distinct experimental methods and protocols and eventually described as different populations.