Figure 1.

In vitro characterization of human MSCs. Immunophenotyping of hMSCs by flow cytometry (a) and trilineage differentiation (b). For immunophenotyping, hMSCs were stained with the indicated antibodies and then analyzed by flow cytometry. Cells strongly express the markers (CD29, CD44, CD73, CD90, CD105) associated with the MSCs, while expression of hematopoietic (CD34, CD45, HLA-DR) and endothelial (CD106) markers is markedly reduced. Black open histograms indicate isotype-matched controls for each antibody; colored open histograms represent positive reactivity. Trilineage differentiation assays of hMSCs shows representative images of alizarin red, oil-red-o, and Alcian blue staining of osteocytes (B), adipocytes (D), and chondrocytes (F), after in vitro differentiation. Corresponding undifferentiated hMSCs (A, C, E) are shown as controls.