Stem cells are defined as undifferentiated cells that have the capacity to self-renew and to differentiate into various mature cells at a single cell level . Stem cells support normal embryogenesis and postnatal life. Stem cells serve to renew tissue throughout an individual’s postnatal life by replacing the cells that are lost owing to everyday wear and tear in our bodies. Bone marrow contains two types of stem cells: hematopoietic stem cell (HSC) and mesenchymal stem cells (MSCs). HSCs are able to give rise to all cells in the hematopoietic system [99, 100]. Injection of a single mCD34(lo/-), c-Kit+, Sca-1(+), lineage markers negative (Lin-) cell resulted in long-term reconstitution of the lymphohematopoietic system . MSCs are multipotent, might be immune privileged [59, 81], and can be expanded easily ex vivo. MSCs isolated from either adult bone marrow or other origin such as adipose tissue have shown a great potential for cell therapy because these cells possess multipotent capabilities , proliferate rapidly, induce angiogenesis, and differentiate into myogenic and other cells [111, 115]. MSCs have been widely used for tissue engineering. In this chapter, we focus on MSCs.
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