Chapter 49 - Mesenchymal stem cells in musculoskeletal tissue engineering

Abstract

Mesenchymal stem cells (MSCs) found in adult tissues function as progenitor cells that can proliferate and differentiate into various mesenchymal cell lineages, including those that are the building blocks of musculoskeletal system. Due to their ease of isolation, extensive proliferation capacity, and multilineage differentiation potential, MSCs are considered the cell type of choice for musculoskeletal tissue engineering. This chapter will first survey current knowledge of MSC biology that serves as the scientific foundation to guide approaches in musculoskeletal tissue engineering. Relevant information regarding MSC tissue origin, isolation, and in vitro culture, and factors controlling their proliferation as well as multipotential differentiation will be reviewed. In addition, recent recognition of the immunosuppressive and immunomodulatory properties of MSCs will be discussed, as this is critical for the safe usage of MSCs in allogeneic transplantation, which is often the case with tissue-engineered products. In the second part, we survey the use of MSCs in the engineering of musculoskeletal tissues, including cartilage, bone, tendon, and osteochondral constructs. We review the biological processes that regulate multilineage differentiation of MSCs and the factors that regulate the ultimate outcome of engineered tissue replacement, with particular focus on cartilage and bone. Current approaches to optimizing the three critical elements of successful tissue engineering, namely, cells, scaffolds, and environment, are discussed, with emphasis on the promotion of cartilage tissue engineering and restoration. While MSCs hold great potential for musculoskeletal systems, there are challenges, from a better understanding of their biology, to the application of such information to optimize tissue neogenesis and the development of functional scaffolds for tissue engineering.