Human umbilical cord blood-derived stromal cells: A new source of stromal cells in hematopoietic stem cell transplantation.

The hematopoietic inductive microenvironment (HIM), which is composed of stromal cells, extracellular matrix and cytokines, plays a vital role in hematopoietic stem cell transplantation (HSCT). Bone marrow stromal cells (BMSCs), as the main component of HIM, have been well studied. However, the highly invasive procedure of bone marrow (BM) collection limits the clinical application of BMSCs. Human umbilical cord blood-derived stromal cells (hUCBDSCs) isolated and cultured in our laboratory have attracted much attention for their ease collection and low probability of pathophoresis. Previous research demonstrated that hUCBDSCs have numerous functions that are identical to those of BMSCs, for example, hUCBDSCs can support the growth of hematopoietic stem and progenitor cells, especially during the expansion of megakaryocyte colony-forming units (CFU-Mk), promote engraftment after hematopoietic stem cell transplantation (HSCT), exert immunosuppressive effects on xenogenic T cells in vitro and suppress acute graft-versus-host disease (aGVHD) in vivo. Although hUCBDSCs, as new stromal cells, have not been used in clinical practice, they have great practical significance because of their superiority in hematopoiesis and the regulation of immunity.