In the early 1970’s Alexander Fridenstein discovered what are now commonly known as "mesenchymal stem cells" (MSCs). He described them as a population of fibroblastoid adherent cells, isolated from the bone marrow, which had the ability to differentiate into bone and cartilage and to support the growth of in vitro and in vivo hematopoietic stem cells. Fridenstein initially referred to these cells as "colony forming unit-fibroblasts" (CFU-F).

A precise definition: MSCs are adherent cells and they are multipotent, meaning they can be induced to acquire the typical characteristics of various cell types. Phenotypically MSCs express a series of non-specific markers on their surface, including CD44 CD73, CD90, CD105, STRO-1 and CD166 while they are negative for markers typical of hematopoietic cells such as CD14, CD34 and CD45. Thought to be present in all tissues, MSCs have been identified in bone marrow, adipose tissue, placenta, amniotic fluid, and umbilical cord blood. As MSCs are usually present in limited numbers, they can be isolated and expanded in the laboratory (even if they have a limited proliferative capacity) in order to reach clinically relevant numbers for study or therapeutic purposes.

Clinical Applications: In the 1990s, with the development of cell therapy and tissue engineering, the interest in MSCs grew exponentially throughout the world. The potential clinical applications and economic implications led to a race to identify MSCs in various tissues and animal models and to develop new isolation and expansion techniques. Currently, pre-clinical and clinical studies are underway with the goal of identifying MSCs efficacy for treating diseases such as Chron's disease, the prevention and treatment of acute graft-versus host (GVHD) disease, the regeneration of bone-cartilage, nervous tissue, and cardiac muscle tissue, to cite some examples. For more information on ongoing clinical trials worldwide, please visit http://www.clinicaltrials.gov..