CD45+/CD133+ positive cells expanded from umbilical cord blood expressing PDX-1 and markers of pluripotency

Human umbilical cord blood (UCB) contains cells able to differentiate into nonhaematopoietic cell lineages. It also contains cells similar to primitive embryonic stem cells (ESCs) that can differentiate into pancreatic-like cells. However, little data has been reported regarding the possibility of expanding these cells or their differential gene expression occurring in vitro. We expanded previously frozen UCB cells by treatment with Stem Cell Factor (SCF) and Granulocyte-Macrophage Colony Stimulating Factor (GM-CSF) in the presence of valproic acid (VPA). Gene expression profiles for beta-cell differentiation and pluripotency (embryo stem cell phenotype) were analysed by RT-PCR and immunocytochemistry. There was a dramatic expansion ( <150 fold) of hematopoietic progenitors (CD45+/CD133+) that also expressed embryo markers of pluripotency (nanog, kfl-4,sox-2,oct3/4 and c-myc), nestin, pancreatic markers as pax-4, ngn-3, pdx-1 and syt-1. UCB cells can be expanded to produce large numbers of cells of hematopoietic lineage that naturally (without retroviral vectors or transposons) express a gene pattern compatible with endocrine pancreatic precursors and markers of pluripotency. Our results confirm that frozen UCB cells can be dramatically expanded along the hematopoietic cell lineage (CD45+/CD133+) which express both markers of pluripotency and a gene pattern compatible with endocrine pancreatic precursors.