In vitro differentiation potential of human embryonic versus adult stem cells

Background: There is widespread controversy regarding the potential of human neural stem cells and human mesenchymal stem cells (hMSCs) to form cell types outside of their normal developmental lineage. A greater understanding of the differentiation potential and bias of these stem cell types would allow researchers to select the cell type that best suits the research or clinical need at hand. Materials & methods: We used identical in vitro protocols to quantitatively compare the potential of human embryonic stem cells, human neural stem cells and hMSCs to differentiate into specific ectodermal or mesodermal lineages. Results: Our findings demonstrate that human embryonic stem cells and human neural stem cells have the ability to differentiate into high purity neuronal progenitor or oligodendrocyte progenitor cultures. By contrast, hMSCs generated exceedingly limited numbers of neural lineages. Both human embryonic stem cells and hMSCs generated adipocytes and osteocytes when exposed to mesodermal differentiation conditions. Conclusion: These studies underscore the importance of distinguishing differentiation potential from differentiation bias, an important consideration in the development of cell replacement strategies.