Identification of a candidate human neurohematopoietic stem-cell population

It was recently reported that transplantation of clonally derived murine ne urosphere cells into sublethally irradiated allogeneic hosts leads to a don or-derived hematopoietic reconstitution. The confirmation of the existence of a common neurohematopoietic stem cell in the human brain will have a sig nificant effect on stem cell research and on clinical transplantation. Here , it is demonstrated that the human fetal brain contains separate but overl apping epidermal growth factor (EGF)-responsive and basic fibroblast growth factor (FGF-2)-responsive neural stem cells. The majority (> 85%) of cells within these EGF- and/or FGF-2-generated neurospheres express characterist ic neural stem/progenitor cell markers including nestin, EGF receptor, and FGF-2 receptor. These neural stem cells can be continuously passaged in vit ro, and demonstrate a constant 20-fold expansion in every passage for up to the fifth passage (the longest period that has been carried out in the aut hors' laboratory). These neural stem cells are multipotential for neurons, astrocytes, and oligodendrocytes. After transplantation into SCID-hu mice, all neural stem cells, regardless of passages, culture conditions, and dono rs, are able to establish long-term hematopoietic reconstitution in the pre sence of an intact human bone marrow microenvironment. (C) 2001 by The Amer ican Society of Hematology.