title: [Concept of mesenchymal stem cells: bring more insights into functional research of MSC].
abstract: Mesenchymal stem cells have generated great interest among researchers and physicians due to their unique biological characteristics and potential clinical applications. Here, I propose for the first time the concept of a hierarchical system which is composed of all mesenchymal stem cells from post-embryonic subtotipotent stem cells to MSC progenitors. Post-embryonic subtotipotent stem cells are left-over cells during embryonic development and are on the top of the hierarchy. MSC system is a combination of cells that are derived from different stages of embryonic development, possess different differentiation potential and ultimately give rise to cells that share a similar set of phenotypic markers. The concept of MSC system has important implications: (1) it entirely explains the three important biological characteristics of MSC: stem cell properties of MSC, MSC as components of tissue microenvironment and immunomodulatory functions of MSC. (2) It balances immune responses and tissue metabolism. (3) It could provide tissue-specific stem cells for clinical application with high efficiency and safety. In a word, this concept constitutes an important part of the biological properties of MSC and will help researchers gain better insight into MSC.
authors.affiliation: Chinese Academy of Medical Science, Beijing, China. chunhuaz@public.tpt.tj.cn
authors.forename: Chun-Hua
authors.initials: CH
authors.lastname: Zhao
mesh_terms: D002454:Cell Differentiation; D060833:Cellular Microenvironment; D006801:Humans; D056747:Immunomodulation; D059630:Mesenchymal Stem Cells / Q000276:immunology* / Q000502:physiology*; D010641:Phenotype