(英文)
3.4 Summary of section 3
♦ Spheres differentiated into cells derived from all three germ layers in vivo and in vitro
3.5 Discussion
Spheres differentiated into cells derived from three germ layers in vitro. It is yet answered that it was either differentiation or trans-differentiation. Also it is hard to refer the difference from in vitro differentiation potential of mesenchymal stem cells.
However, at least sphere forming cells enabled to generate various mature cells. In addition, in vivo differentiation assay proved that sphere forming cells were indeed stem cells, but distinct from ES cells in proriferative potential. The relationship between proliferative potential and differentiation potential has yet been understood. Spheres in this study showed differentiation potential which fulfill the critereia for both mesenchymal stem cells and neural stem cells. We believe that the spheres studied contain precursor cells to both mesenchymal and neural stem cells lineages.
It is important to note that cells described above, were propagated as non-adherent spheres, and are not known to exist in vivo. The in vitro behavior of cells in the spheres is likely to be very different from cells that reside in vivo. How these stem cells harbor in adult body and how they exert their potential
The spheres generated seemed to be composed of heterogenous populations of cells,with some markers expressed in some spheres, and other markers expressed in different spheres generated from cells isolated from the same tissue, at the same time. We believe that these differences also may be a function of the environment in which the cells were maintained.
