Adult mesenchymal stem cells and cell-based tissue engineering

Abstract

The identification of multipotential mesenchymal stem cells (MSCs) derived from adult human tissues, including bone marrow stroma and a number of connective tissues, has provided exciting prospects for cell-based tissue engineering and regeneration. This review focuses on the biology of MSCs, including their differentiation potentials in vitro and in vivo, and the application of MSCs in tissue engineering. Our current understanding of MSCs lags behind that of other stem cell types, such as hematopoietic stem cells. Future research should aim to define the cellular and molecular fingerprints of MSCs and elucidate their endogenous role(s) in normal and abnormal tissue functions.

Figure 1

Lineage potential of adult human MSCs. MSCs are characterized by their multilineage differentiation potentials, including bone, cartilage, adipose tissue, muscle, tendon, and stroma. This figure depicts some of the in vitro culture conditions (boxed) that promote the respective differentation process into a specific lineage. Signaling pathways and/or components or events shown to be involved in lineage-specific differentiation are in italics. See text for details. Dotted arrowheads denote potential 'reverse' differentiation events. bFGF, basic fibroblast growth factor; bHLH, basic helix–loop–helix; BMP, bone morphogenetic protein; Cbfa1, core binding factor alpha 1; ECM, extracellular matrix; FGF, fibroblast growth factor; GDF, growth/differentiation factor; IBMX, 3-isobutyl-1-methylxanthine; LRP, low-density lipoprotein receptor-related peptide; MAPK, mitogen-activated protein kinase; PDGF, platelet-derived growth factor; SMAD, vertebrate homologue of Drosophila Mothers Against Decapentaplegic (MAD); TGF-β, transforming growth factor beta; WISP, Wnt-1-inducible protein.