Chemically defined cytokine-free expansion of human haematopoietic stem cells

Abstract The ex vivo expansion of human hematopoietic stem/progenitor cells (HSPCs) has important applications in both basic research and clinical transplantation therapy. Here, we introduce the protocol of a novel culture system that supports the long-term ex vivo expansion of human HSPCs, achieved through the complete replacement of cytokines and albumin by chemical agonists and a caprolactam-based polymer. A phosphoinositide 3-kinase activator in combination with a thrombopoietin receptor agonist and the pyrimidoindole derivative UM171 were sufficient to stimulate functional expansion of umbilical cord blood-derived HSCs. We envision that this chemically defined expansion culture system will help to advance clinical HSC therapies.