The MSCs, commonly referred to today as “mesenchymal stem cells” (MSCs), were first described by Alexander Friedenstein in the 1970s as a population of adherent, fibroblast-like cells isolated from bone marrow. These cells demonstrated the ability to differentiate into bone and cartilage tissue and to support the growth of hematopoietic stem cells both in vitro and in vivo. Initially, Friedenstein named these cells “colony-forming unit-fibroblast” (CFU-F).

A precise definition: MSCs are adherent and multipotent cells, meaning they can be induced to acquire the characteristics of various cell types. Phenotypically, they express a range of nonspecific markers on their surface, including CD44, CD73, CD90, CD105, STRO-1, and CD166, while they are negative for markers typically associated with hematopoietic cells, such as CD14, CD34, and CD45. Likely present in all tissues, MSCs have been identified in bone marrow, adipose tissue, placenta, amniotic fluid, and umbilical cord blood. Usually found in limited numbers, MSCs can be isolated and expanded in the laboratory to reach clinically relevant numbers for study or therapeutic purposes, despite their limited proliferative capacity.

Clinical applications: In the 1990s, with the development of cell therapy and tissue engineering, interest in these cells grew exponentially worldwide. The potential clinical applications and economic implications led to a race to identify MSCs in various tissues and animal models, as well as the development of new isolation and expansion techniques. Currently, MSCs are being investigated in preclinical and clinical studies to evaluate their effectiveness for conditions such as Crohn's disease, the prevention and treatment of acute graft-versus-host disease (GVHD), and the regeneration of bone-cartilage, nervous, and cardiac tissues, among others. For more information on ongoing clinical trials worldwide, visit http://www.clinicaltrials.gov.