Ex-vivo Expansion of Cord Blood Hematopoietic Stem Cells in Serum-Free Medium with Feeder Layer - A New Hope for Successful Cord Blood Transplantation in Adults.

Background: Umbilical cord blood is widely regarded as a viable option for allogeneic hematopoietic stem cell transplantation (HSCT) and serves as a potential alternative to bone marrow due to its numerous advantages. These include a non-invasive collection process, a high concentration of hematopoietic stem and progenitor cells, and a lower risk of graft rejection. However, its application in adult patients is limited by the suboptimal dose of stem cells available in a single umbilical cord blood unit. This insufficient cell dose increases the risk of engraftment failure and post-transplant mortality, posing a significant challenge for its use in adult populations. Materials and Methods: This study aims to develop a protocol for expanding umbilical cord blood mononuclear cells (UCB-MNCs) using a serum-free culture medium called StemSpan, supplemented with a mesenchymal stem cell (MSC) feeder layer and a combination of growth factors. The growth factors used include stem cell factor (SCF), thrombopoietin (TPO), fibroblast growth factor-1 (FGF-1), and heparin. The expansion culture was applied to 20 UCB samples and maintained over a period of 13 days. Data collected from the experiments were analyzed using the SPSS program (Statistical Package for the Social Sciences) for Windows, version 21. Results: The protocol led to a notable increase in the viable mononuclear cell counts, the absolute hematopoietic stem and progenitor cell counts, and the clonogenic progenitors. Conclusion: This designed protocol could support the expansion of the umbilical cord blood mononuclear cells, including hematopoietic stem and progenitor cells, which could provide hope for better engraftment in adult patient transplantations. The designed protocol could effectively promote the expansion of umbilical cord blood mononuclear cells, particularly hematopoietic stem and progenitor cells. This advancement offers promising potential for improving engraftment outcomes in adult patient transplantations.