title: "Mesenchymal" stem cells.
abstract: Two opposing descriptions of so-called mesenchymal stem cells (MSCs) exist at this time. One sees MSCs as the postnatal, self-renewing, and multipotent stem cells for the skeleton. This cell coincides with a specific type of bone marrow perivascular cell. In skeletal physiology, this skeletal stem cell is pivotal to the growth and lifelong turnover of bone and to its native regeneration capacity. In hematopoietic physiology, its role as a key player in maintaining hematopoietic stem cells in their niche and in regulating the hematopoietic microenvironment is emerging. In the alternative description, MSCs are ubiquitous in connective tissues and are defined by in vitro characteristics and by their use in therapy, which rests on their ability to modulate the function of host tissues rather than on stem cell properties. Here, I discuss how the two views developed, conceptually and experimentally, and attempt to clarify the confusion arising from their collision.
authors.affiliation: Department of Molecular Medicine, Sapienza University of Rome, 00161 Rome, Italy; email: paolo.bianco@uniroma1.it.
authors.forename: Paolo
authors.initials: P
authors.lastname: Bianco
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000145:classification / Q000166:cytology; D001842:Bone and Bones / Q000166:cytology; D051929:CD146 Antigen / Q000032:analysis; D002469:Cell Separation / Q000379:methods; D064987:Cell- and Tissue-Based Therapy; D002478:Cells, Cultured; D002999:Clone Cells / Q000166:cytology; D003238:Connective Tissue / Q000276:immunology; D006801:Humans; D056747:Immunomodulation; D045164:Mesenchymal Stem Cell Transplantation; D059630:Mesenchymal Stem Cells / Q000145:classification / Q000166:cytology*; D051379:Mice; D008954:Models, Biological; D020286:Pericytes / Q000166:cytology; D039904:Pluripotent Stem Cells / Q000166:cytology; D011828:Radiation Chimera; D055153:Stem Cell Niche; D017154:Stromal Cells / Q000145:classification / Q000166:cytology; D016042:Transplantation, Heterotopic
chemical_list: D051929:CD146 Antigen; C497903:Mcam protein, mouse
keywords: bone marrow niche; bone marrow stromal cells; cell therapy; pericyte; transplantation