Mesenchymal Stem Cells: In Vitro Differentiation among Bone and Cartilage Cell Lineages

Introduction Stem cell criteria Stem cells are defined as undifferentiated somatic cells having the ability to produce varieties of fully-differentiated progenies in response to the appropriate environment either in vitro or in vivo (1). Nowadays, at least four criteria are considered for cells to be known as stem cells. Stem cells should have the ability to undergo extensive proliferation for a long time. This property is called as self-renewal potential. Stem cells should also have the capacity to undergo multilineage differentiation in the presence of appropriate culture condition, for example, mesenchymal stem cells represent the potential to generate fibroblast, osteoblast, chondrocye and adipocyte. In addition, stem cells need to have the potential to regenerate a tissue defects upon transplantation. The last but not the least, stem cells should have the potential to produce fully-differentiated progenies even in the absence of any tissue damages in vivo (2).