Heterogeneous Responses of Human Bone Marrow Stromal Cells (Multipotent Mesenchymal Stromal Cells) to Osteogenic Induction

Abstract

Tissue engineering is a novel technology developed for the regeneration of tissue using cultured cells, scaffolds, and osteogenic inductive signals. Bone marrow stromal cells (also designated as multipotent mesenchymal stromal cells, mesenchymal stem cells, or MSCs) have been the most commonly used cell source for bone tissue engineering. For efficient bone tissue engineering, the cells must be expanded in vitro and induced into osteogenic cells with an osteoinductive reagent such as dexamethasone. Recently, physiological factors such as bone morphogenetic proteins have been shown to induce the osteogenic lineage of bone marrow stromal cells. Osteogenic reagents have been widely used in both basic and clinical studies. However, it is apparent that the cellular responses to those reagents have been heterogeneous in human cells compared with animal cells, which possess a more uniform genetic background. Since the clinical use of those factors will increase further in the cases of orthopaedic applications and in the context of tissue engineering, these responses could be a serious problem in the future. In this chapter, the heterogeneous response of human bone marrow stromal cells to those inductive factors is discussed with reference to possible underlying mechanisms.