Mesenchymal Stem Cells

Abstract

Within the bone marrow stroma there exists a subset of nonhematopoietic cells referred to as mesenchymal stem or mesenchymal progenitor cells. These cells can be ex vivo expanded and Induced, either in vitro or in vivo, to terminally differentiate Into osteoblasts, chondrocytes, adlpocytes, tenocytes, myotubes, neural cells, and hematopoietic-supporting stroma. The multlpotential of these cells, their easy isolation and culture, as well as their high ex vivo expansive potential make these cells an attractive therapeutic tool. In this work we will review the information dealing with the biology of mesenchymal progenitors as it has been revealed mainly by ex vivo studies performed with bone marrow-derived cells. The discussed topics include, among others, characteristics of mesenchymal progenitors, evidence for the existence of a vast repertoire of un-Committed and committed progenitors both in the bone marrow and in mesenchymal tissues, a diagram for their proliferative hierarchy, and comments on mobilization, microenvironment, and clinical use of mesenchymal progenitors. Despite the enormous data available at molecular and cellular levels, it is evident that a number of fundamental questions still need to be resolved before mesenchymal progenitors can be used for safe and effective clinical applications in the context of both cell and gene therapies.

Expression, signaling, and function of P2X7 receptors in bone

“…1). Osteoblasts develop from mesenchymal stem cells that also give rise to other cell types including chondrocytes, adipocytes, and fibroblasts [4]. Commitment to the osteoblast lineage is controlled by a complex series of transcriptional events that are initiated and maintained by a number of extracellular stimuli, including bone morphogenetic proteins, transforming growth factor-β, Wnts, insulin-like growth factors, fibroblast growth factors, platelet-derived growth factors, parathyroid hormone and glucocorticoids [2,5].…”

Development of Novel Monoclonal Antibodies that Define Differentiation Stages of Human Stromal (Mesenchymal) Stem Cells

“…Human MSC are obtained from bone marrow aspirates taken from the iliac crest of normal donors, and represent a minor fraction of bone marrow derived mononuclear cells (BMMNC) with a frequency of 2-5 MSCs per 10 6 BMMNC (Minguell et al, 2001). Traditionally, MSC are isolated from BMMNC by their ability for selective adherence to plastic culture dishes (Kassem et al, 1991).…”

Site-specific gene modification by oligodeoxynucleotides in mouse bone marrow-derived mesenchymal stem cells

“…Based on the current data, MSCs are thought to be negative for hematopoietic surface markers such as CD34, CD45, CD14, CD31, CD133 and positive for CD105, CD166, CD54, CD55, CD13 and CD44 (11)(12)(13)(14)(15)(16)(17)(18). 1,3,42 Despite the fact that no perspective markers exclusively defining MSC are currently available, there is also general agreement that MSCs lack typical hematopoietic antigens, such as CD45, CD34 and CD14.…”

“…Bone marrow contains mesenchymal progenitor cells, called mesenchymal stem cells (MSCs) that have the capacity to differentiate into a variety of unique mesenchymal tissues including bone, cartilage, muscle, fat, tendon, marrow stroma and other connective tissues. [1][2][3][4][5] The multipotential of MSCs, their relatively easy isolation, culture and ex vivo expansive potential have attracted considerable attention in efforts to develop cell and gene therapies and have made these cells an attractive therapeutic tool in a wide range of clinical applications. 6 During the past decade many different viral vectors including retrovirus, 7 adenovirus, [8][9][10][11][12][13] lentivirus [13][14][15][16] and adeno-associated virus 13,[17][18][19][20] have been utilized to deliver genes to or modify genes in MSCs.…”