Résumé :
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Stem cells are usually located in a niche more or less defined both micro-anatomically and molecularly that insures their maintenance, their quiescence state and the self-renewal. As an example, part of hematopoietic stem cells is found in a niche formed by osteoblasts and by stromal cells, which is characterized by its weak partial pressure in oxygen. The so-called satellite cells (SCs), skeletal muscle stem cells are also localized in a niche clearly defined between myofibre sarcoplasmic membrane and basal lamina. We have previously demonstrate that most of these SCs are in close contact with endothelial cells but a minority of them are more distant (more than 10?m) and probably in a more hypoxic environment than cells in close contact with capillaries. Oxygen delivery and supply to tissues and especially stem cells appears for us as a key point in stem cell biology. We investigate the survival of hematopoietic and SCs from both human and murine tissues in severe hypoxic/anoxic conditions and in particular in post-mortem condition. We have shown that hematopoietic stem cells as well as SCs survive for a long period after death in tissues. Extracted from post mortem tissues, these cells are perfectly functional and capable of both in vitro and in vivo differentiation. Among the various tissue alterations that occur after death, hypoxia/anoxia is one of the more early and severe. We've demonstrated that, very surprisingly, satellite cells survive for many days in complete anoxia. This work points post mortem tissues as a source of functional stem cells even for therapeutic purposes.
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