Mesenchymal stem cells. A potential source for skeletal repair.

The bone marrow serves as a reservoir for different classes of stem cells. In addtion to haematopoietic stem cells the bone marrow comprises a population of marrow stromal cells or mesenchymal stem cells (MSCs). Stromal cells exhibit multilineage differentiation capacity, and are able to generate progenitors with restricted developmental potential, including fibroblasts, osteoblasts, adipocytes, and chondrocyte progenitors. Recently, techniques have become available to isolate and grow mesenchymal progenitors and to manipulate their growth under defined in vitro culture conditions. As a result MSCs can be rapidly expanded to numbers that are required for clinical application. Here the role of MSCs for repair of bone and cartilage is discussed.