Custom stem cells to treat leukemia?
Researchers of the Institut Pasteur and CNRS come from to determine how hematopoietic stem cells (HSCs) are born, the source of all the blood and immune cells in the body. Using real-time imaging technology on the zebrafish embryo, they observed that these stem cells were formed from cells in the wall of the aorta, the central artery of the embryo.
These works, published in the journal Nature, are still very basic, but suggest that it may be possible to regenerate human HSCs in the laboratory from blood vessel biopsies. They would then provide hope for the personalized treatment of leukemia patients, whose HSCs must be replaced after chemotherapy or radiotherapy to restore healthy blood and immune systems.
Two researchers from the Institut Pasteur and the CNRS, in the Macrophage and immunity development unit, at the Institut Pasteur, have just demonstrated that hematopoietic stem cells, which produce blood cells throughout their life, form from the cells of the wall of the aorta of the embryo. Using a high-resolution imaging technique to track the evolution of the aorta in zebrafish in real time, a model of choice for the study of blood cell formation - or hematopoiesis - scientists were able to describe precisely the stages of the birth of these stem cells, and provide an answer to the question of their origin, which had been debated for several decades.
Observations show that some endothelial cells that form the aorta bend, round and then close on themselves to finally individualize and detach, while preserving the integrity of the vessel. The endothelial cell then becomes a traveling strain cell, which will divide to give later all the diversity of blood cells.
This discovery shows that already specialized cells, such as those that make up a vessel, can naturally be reprogrammed to become multipotential stem cells.
This work, although still very fundamental, could lead to therapeutic applications, especially for the treatment of leukemia patients, whose HSCs would have been destroyed by radiotherapy or chemotherapy: once the factors of this "dedifferentiation" identified, it may be possible to generate in vitro, in laboratory, hematopoietic stem cells from a simple biopsy taken from the patients' own blood vessels. Re-introduced in these patients to replace the old ones, the new CSH, generated to measure for each patient, could then reconstitute the blood and immune systems.