Concise Review: Mesenchymal Stem Cells: From Roots to Boost

It was shown as long as half a century ago that bone marrow is a source of not only hematopoietic stem cells, but also stem cells of mesenchymal tissues. Then the term "mesenchymal stem cells" (MSCs) was coined in the early 1990s, and more than a decade later, the criteria for defining MSCs have been released by the International Society for Cellular Therapy. The easy derivation from a variety of fetal and adult tissues and undemanding cell culture conditions made MSCs an attractive research object. It was followed by the avalanche of reports from preclinical studies on potentially therapeutic properties of MSCs, such as immunomodulation, trophic support and capability for a spontaneous differentiation into connective tissue cells, and differentiation into the majority of cell types upon specific inductive conditions. Although ontogenesis, niche, and heterogeneity of MSCs are still under investigation, there is a rapid boost of attempts at clinical applications of MSCs, especially for a flood of civilization-driven conditions in so quickly aging societies, not only in the developed countries, but also in the populous developing world. The fields of regenerative medicine and oncology are particularly extensively addressed by MSC applications, in part due to the paucity of traditional therapeutic options for these highly demanding and costly conditions. There are currently almost 1,000 clinical trials registered worldwide at ClinicalTrials.gov, and it seems that we are starting to witness the snowball effect with MSCs becoming a powerful global industry; however, the spectacular effects of MSCs in the clinic still need to be shown. Stem Cells 2019;37:855-864.