Human blood stem cells
Scientists at the University of Edinburgh’s MRC Centre for Regenerative Medicine are one step closer in establishing exactly the right protocol needed to turn pluripotent stem cells into blood stem cells in the laboratory, an essential step in the quest to find a more effective treatment for blood cancers like leukaemia.

During the study, carried out in collaboration with the Scottish National Blood Transfusion Service, the Edinburgh based MRC Centre for Reproductive Health and the Centre for Forensic Science at the University of Strathclyde, researchers discovered blood stem cells are first developed in the aorta of a human embryo, 30-35 days after fertilisation.

Up to this point scientists were not sure when and where the first blood stem cells were formed: in the aorta, the yolk sac, or other tissues like the placenta.

The researchers also discovered that the blood stem cells found in the vessel walls of the embryonic aorta are much more powerful than the blood stem cells in the bone marrow and umbilical cord blood currently used for clinical transplantation into patients.

Dr Andrejs Ivanovs, who carried out the study, was very excited with his results: “These first blood stem cells in the aorta are very powerful. Each one can make more than 300 daughter stem cells and usually only 100 cells are needed for a successful clinical transplant. Our next step is to investigate how we can make blood stem cells in the bone marrow and umbilical cord blood just as powerful so patients can be treated more successfully.”

Prof Alexander Medvinsky, who led the study, added: “This is a very important milestone. Now that we understand where and when the first blood stem cells are made, we will be able to target these cells more easily and develop a better protocol to grow them more efficiently in the lab with the ultimate aim to develop more effective treatments for patients.”

The study, funded by the Leukaemia and Lymphoma Research, the Medical Research Council and the Wellcome Trust, was published in The Journal of Experimental Medicine on 31st October 2011.