title: A Novel View of the Adult Stem Cell Compartment From the Perspective of a Quiescent Population of Very Small Embryonic-Like Stem Cells.
abstract: Evidence has accumulated that adult hematopoietic tissues and other organs contain a population of dormant stem cells (SCs) that are more primitive than other, already restricted, monopotent tissue-committed SCs (TCSCs). These observations raise several questions, such as the developmental origin of these cells, their true pluripotent or multipotent nature, which surface markers they express, how they can be efficiently isolated from adult tissues, and what role they play in the adult organism. The phenotype of these cells and expression of some genes characteristic of embryonic SCs, epiblast SCs, and primordial germ cells suggests their early-embryonic deposition in developing tissues as precursors of adult SCs. In this review, we will critically discuss all these questions and the concept that small dormant SCs related to migratory primordial germ cells, described as very small embryonic-like SCs, are deposited during embryogenesis in bone marrow and other organs as a backup population for adult tissue-committed SCs and are involved in several processes related to tissue or organ rejuvenation, aging, and cancerogenesis. The most recent results on successful ex vivo expansion of human very small embryonic-like SC in chemically defined media free from feeder-layer cells open up new and exciting possibilities for their application in regenerative medicine.
authors.affiliation: From the Department of Medicine, Stem Cell Biology Program at the James Graham Brown Cancer Center, University of Louisville, KY (M.Z.R., J.R., M.S., D.M.M., M.K.); Department of Regenerative Medicine, Warsaw Medical University, Poland (M.Z.R., M.K.); and Department of Biomedical Sciences, University of Ulsan College of Medicine, Seoul, South Korea (D.-M.S.). mzrata01@louisville.edu.
authors.forename: Mariusz Z
authors.initials: MZ
authors.lastname: Ratajczak
authors.affiliation: From the Department of Medicine, Stem Cell Biology Program at the James Graham Brown Cancer Center, University of Louisville, KY (M.Z.R., J.R., M.S., D.M.M., M.K.); Department of Regenerative Medicine, Warsaw Medical University, Poland (M.Z.R., M.K.); and Department of Biomedical Sciences, University of Ulsan College of Medicine, Seoul, South Korea (D.-M.S.).
authors.forename: Janina
authors.initials: J
authors.lastname: Ratajczak
authors.affiliation: From the Department of Medicine, Stem Cell Biology Program at the James Graham Brown Cancer Center, University of Louisville, KY (M.Z.R., J.R., M.S., D.M.M., M.K.); Department of Regenerative Medicine, Warsaw Medical University, Poland (M.Z.R., M.K.); and Department of Biomedical Sciences, University of Ulsan College of Medicine, Seoul, South Korea (D.-M.S.).
authors.forename: Malwina
authors.initials: M
authors.lastname: Suszynska
authors.affiliation: From the Department of Medicine, Stem Cell Biology Program at the James Graham Brown Cancer Center, University of Louisville, KY (M.Z.R., J.R., M.S., D.M.M., M.K.); Department of Regenerative Medicine, Warsaw Medical University, Poland (M.Z.R., M.K.); and Department of Biomedical Sciences, University of Ulsan College of Medicine, Seoul, South Korea (D.-M.S.).
authors.forename: Donald M
authors.initials: DM
authors.lastname: Miller
authors.affiliation: From the Department of Medicine, Stem Cell Biology Program at the James Graham Brown Cancer Center, University of Louisville, KY (M.Z.R., J.R., M.S., D.M.M., M.K.); Department of Regenerative Medicine, Warsaw Medical University, Poland (M.Z.R., M.K.); and Department of Biomedical Sciences, University of Ulsan College of Medicine, Seoul, South Korea (D.-M.S.).
authors.forename: Magda
authors.initials: M
authors.lastname: Kucia
authors.affiliation: From the Department of Medicine, Stem Cell Biology Program at the James Graham Brown Cancer Center, University of Louisville, KY (M.Z.R., J.R., M.S., D.M.M., M.K.); Department of Regenerative Medicine, Warsaw Medical University, Poland (M.Z.R., M.K.); and Department of Biomedical Sciences, University of Ulsan College of Medicine, Seoul, South Korea (D.-M.S.).
authors.forename: Dong-Myung
authors.initials: DM
authors.lastname: Shin
mesh_terms: D053687:Adult Stem Cells / Q000502:physiology* / Q000637:transplantation; D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D053595:Embryonic Stem Cells / Q000502:physiology* / Q000637:transplantation; D005855:Germ Layers / Q000502:physiology / Q000637:transplantation; D006801:Humans; D032383:Myocytes, Cardiac / Q000502:physiology* / Q000637:transplantation; D039904:Pluripotent Stem Cells / Q000502:physiology / Q000637:transplantation; D033581:Stem Cell Transplantation / Q000379:methods*
keywords: adult stem cells; germ layers; hematopoietic stem cells; parental imprinting; ras-GRF1; stem cells; very small embryonic like stem cells