Human mesenchymal stem cells are thought to be multipotent cells, which are
present in adult marrow, that can replicate as undifferentiated cells and
that have the potential to differentiate to Lineages of mesenchymal tissues
, including bone; cartilage, fat, tendon, muscle, and marrow stroma. Cells
that have the characteristics of human mesenchymal stem cells were isolated
from marrow aspirates of volunteer donors. These cells displayed a stable
phenotype and remained as a monolayer in vitro. These adult stem cells coul
d be induced to differentiate exclusively into the adipocytic, chondrocytic
, or osteocytic Lineages. Individual stem cells were identified that, when
expanded to colonies, retained their multilineage potential.