Mesenchymal Stem Cells

Abstract

Since Friedenstein and co-workers first reported bone marrow-derived mesenchymal stem cells (MSCs) during the early 1970s, several researchers have focused on their biology and in vitro and in vivo characterization in experimental animal models. After their initial isolation from the bone marrow, MSCs have also been isolated from almost every tissue including the adipose tissue, liver, skeletal muscle, amniotic fluid, umbilical cord blood, and dental pulp. Following the minimum criteria recommended by the International Society for Cellular Therapy, human MSCs show preferred plastic adherence in culture, can undergo trilineage differentiation (i.e., adipogenic, chondrogenic, and adipogenic), besides the expression of CD44, CD71, CD90, CD105, and lack of CD34 and CD45 expression. Other important markers include Stro-1, SSEA-4, CD146, and CD271. This identification criterion has gone a long way in comparing the findings from independent research labs involved in MSCs research. MSCs show remarkable immunomodulatory and anti-inflammatory properties besides their ability to undergo transdifferentiation and paracrine activity. These characteristics make them ideal candidates for cell therapy and for this reason; there are numerous clinical trials worldwide that use MSCs to treat various pathologies including myocardial infarction for which they have entered into Phase III trials. They also secrete exosomes as part of their paracrine activity, which has led to the emergence of “cell therapy without cells” approach. Several studies have suggested that exosomes, small extracellular vesicles, derived from MSCs could serve as a novel therapeutic tool in the field of regenerative medicine. This book chapter discusses in-depth the advancements in the field of MSCs-based cell therapy and cell-free therapy using their derivative exosomes with a special focus on the clinical perspective.