Mesenchymal stem cells and osteoregeneration.

Adult stem and progenitor cells have strong proliferation and differentiationpotentials allowing them to regenerate damaged tissues. Inthe human adult bone marrow, two types of stem and progenitorcells can be found: hematopoietic stem cells and non-hematopoieticstem cells such as mesenchymal stem cells (MSCs). These MSCsare the origin of all connective tissue cells. Therefore, they have theability to regenerate cartilage, bone, muscle, tendon, ligament andfat. They are isolated in vitro by using their adhesion capacities onplastic of the culture flasks and by their strong proliferation potentials.Using this protocol, it is possible to obtain several millioncells from 1ml of bone marrow.Cultured MSCs were used in clinical studies for assessing theirosteo-chondrogenic potentials. They were injected to improve theosteogenesis imperfecta disease, to fill bone defects or to regeneratecartilage. Several reports have also shown a potential to regenerateor to preserve vascular cells and cardiomyocytes after ischemia.Besides, MSCs are able to immunosuppress the allogenic T lymphocyteresponses in vitro as well as in vivo.In conclusion, MSCs are stem cells easy to obtain and to expandwith strong regeneration potentials in allogenic and syngenic settings.