Fig. 1.

Multiple criteria for the definition of MSCs. MSCs can be isolated from various origins, such as the bone marrow, adipose tissues, and peripheral blood. In culture, they are adherent to plastic dishes, thus can be purified and expanded by consecutive passaging. Usually, MSCs exhibit heterogeneous population of fibroblast-like shapes. MSCs are multi-potential which can differentiate into cells of mesenchymal tissues, including adipocytes, chondrocytes, and osteocytes. These cells can also trans-differentiate into cells of non-mesenchymal tissues. Usually, mouse and human MSCs are positive for such markers as Sca-1, CD105, CD73, CD44, and CD29, while they are negative for such markers as CD34, CD45, CD11b, MHCII, and CD31. These criteria combined to form a strict definition of MSCs