By Stuart P. Atkinson
The chronic lack of donated blood, with an annual requirement of nearly 90 million units worldwide presents a major problem which, with an increasing world population, will only get worse. Apart from typical blood donation, another possible source of blood cells is through in vitro manipulations of stem cell populations, such as circulating haematopoietic stem cells (HSCs) or, potentially, embryonic stem cells (ESCs) or induced pluripotent stem cells (iPSCs); the latter being particularly attractive for patients with blood-related disease. The advantages of stem cell-derived blood are many; these could potentially provide an unlimited source of the various blood types, and reduce the risk of infectious disease from donated blood. However, to date, the transfusion potential of stem cell-derived blood products generated in vitro has yet to be assessed in man. Now in a study (Giarratana et al) from the group of Luc Douay at UPMC University Paris, France, published online in Blood, these issues have been addressed. They report that in vitro-derived reticulocytes (cultured red blood cells; cRBCs) have a similar functional capacity to native reticulocytes, can mature appropriately in mouse and, importantly, they report the successful transfusion and in vivo survival of cRBCs in a human patient.