Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA.
J Cell Biochem. 2010 Feb 1;109(2):277-82. doi: 10.1002/jcb.22399.
Following the identification of bone marrow multipotent cells that could adhere to plastic and differentiate along numerous mesenchymal lineages in vitro, a considerable effort has been invested in characterizing and expanding these cells, which are now called "mesenchymal stem cells" (MSCs), in vitro. Over the years, numerous lines of evidence have been provided in support of their plasticity, their extraordinary immunomodulatory properties, their potential use for tissue engineering purposes, as well as their ability to be recruited to sites of injury, where they might contribute a "natural in vivo system for tissue repair." Moreover, some studies have attempted the characterization of their cell-surface specific antigens and of their anatomical location in vivo. Lastly, it has been shown that similar cells could be also isolated from organs other than the bone marrow. Despite this impressive body of investigations, numerous questions related to the developmental origin of these cells, their proposed pluripotency, and their role in bone modeling and remodeling and tissue repair in vivo are still largely unanswered. In addition, both a systematic phenotypic in vivo characterization of the MSC population and the development of a reproducible and faithful in vivo assay that would test the ability of MSCs to self-renew, proliferate, and differentiate in vivo are just beginning. This brief review summarizes the current knowledge in the field of study of MSCs and the outstanding questions.
在鉴定出骨髓多能细胞能够在体外黏附于塑料并沿着多种间充质谱系分化后，人们投入了相当大的努力来对这些细胞进行特征描述和体外扩增，这些细胞现在被称为“间充质干细胞”（MSCs）。多年来，提供了大量证据支持它们的可塑性、非凡的免疫调节特性、它们在组织工程中的潜在用途，以及它们被招募到损伤部位的能力，在那里它们可能为“组织修复的天然体内系统”做出贡献。此外，一些研究试图对其细胞表面特异性抗原和体内解剖位置进行特征描述。最后，已经表明，类似的细胞也可以从骨髓以外的器官中分离出来。尽管进行了如此多的研究，但与这些细胞的发育起源、多能性以及它们在体内骨建模和重塑和组织修复中的作用相关的许多问题仍未得到解答。此外，对 MSC 群体进行系统的表型体内特征描述以及开发一种可重复和真实的体内检测方法，以测试 MSC 在体内自我更新、增殖和分化的能力，才刚刚开始。这篇简短的综述总结了 MSCs 研究领域的现有知识和悬而未决的问题。
