Expansion of Haematopoietic Stem and Progenitor Cells: Paving the Way for Next-Generation Haematopoietic Stem Cell Transplantation

Haematopoietic stem cell transplantation (HSCT) is now an established practice with over 70,000 transplants performed annually, and over 1.5 million around the world so far. The practice of HSCT has improved over the years due to advances in conditioning regiments, preparatory practices for patients leading up to the transplant, graft versus host disease (GVHD) and infection prophylaxis, as well as a better selection of patients. However, in many instances, the stem cells supplied to the patient may not be adequate for optimal transplantation outcomes. This may be seen in a few areas including umbilical cord blood transplantation, inadequate bone marrow, peripheral blood stem cell harvest, or gene therapy. Growing and expanding HSCs in culture would provide an increase in cell numbers prior to stem cell infusion and accelerate haematopoietic recovery, resulting in improved outcomes. Several new technologies have emerged in recent years, which have facilitated the expansion of haematopoietic stem and progenitor cells (HSPCs) in culture with good outcomes in vitro, in vivo, and in clinical trials. In this review, we will outline some of the reasons for the expansion of HSPCs as well as the new technologies facilitating the advances in HSCT.