[The bone marrow: a reserve of stem cells able to repair various tissues?].
Hematopoietic stem cells (HSC) have been widely used for autologous and allodeneic transplantation during decades, although little was known about their migration, survival, self-renewal and differentiation process. Their sorting by the CD34(+) marker they express at the cell surface in human has been challenged by the recent discovery of HSC in the CD34(-) compartment that may precede CD34(+) HSC in the differentiation process. Until recently, stem cells present in the bone marrow were thought to be specific for hematopoiesis. Some experiments including clinical trials showing the formation of various tissues, muscle, neural cells and hepatocytes for instance, after transplantation of medullar cells, have challenged this dogma. In fact, the proofs of such a transdifferentiation process by HSC are still missing and the observations may result from the differentiation of other mulipotent stem cells present in the bone marrow, such as mesenchymal stem cells and more primitive multipotent adult progenitor cells (MAPC) and side population (SP) cells.
Cavazzana-Calvo
M
M
Département de biothérapie, Hôpital Necker enfants malades, 149, rue de Sèvres, 75743 Paris. cavazzan@necker.fr
Lagresle
C
C
André-Schmutz
I
I
Hacein-Bey-Abina
S
S
D000818:Animals; D018952:Antigens, CD34; D001854:Bone Marrow Cells / Q000502:physiology*; D016026:Bone Marrow Transplantation; D002455:Cell Division; D006412:Hematopoietic Stem Cells / Q000502:physiology*; D006801:Humans; D013234:Stem Cells
D018952:Antigens, CD34