What Are Mesenchymal Stem Cells?

Mesenchymal germ cell, also known as MSCs, are a type of adult stem cell that can be isolated from many tissues including bone marrow, adipose tissue, placental tissue, and umbilical cord blood. In the body, MSCs reside in the supporting connective tissues and can differentiate into a variety of cell types including osteoblasts, chondrocytes and adipocytes. Due to their multipotent properties and unique immunomodulatory functions, MSCs have become a major focus of regenerative medicine research and clinical trials.

Isolation and Characterization of Mesenchymal Stem Cells

Mesenchymal Stem Cells are most commonly isolated from bone marrow where they make up a very small fraction of total bone marrow cells, around 0.01-0.001%. To harvest MSCs, bone marrow is typically aspirated from the iliac crest of the pelvis and then centrifuged over a density gradient to separate mononuclear cells from other components. These cells are then placed in culture where most non-stem cells will fail to adhere, leaving a population enriched for plastic-adherent MSCs. Additional characterization steps involve analysis of specific surface marker expression by flow cytometry. MSCs are negative for hematopoietic markers like CD34 but positive for CD73, CD90 and CD105.

Multilineage Differentiation Potential

One defining property of MSCs is their ability to differentiate into multiple mesodermal cell types under the right culture conditions. When treated with osteogenic supplements like dexamethasone, ascorbic acid and beta-glycerophosphate, MSCs will differentiate down an osteoblastic lineage and deposit calcium-rich mineralized matrix. Similarly, when cultured in chondrogenic conditions containing TGF-beta supplements, MSCs form cartilage pellets expressing proteins like collagen II and aggrecan. Adipogenic differentiation is induced with insulin, dexamethasone and IBMX, resulting in lipid-filled adipocytes. Demonstrating trilineage potential is a standard test used in characterizing clinical-grade MSC preparations.

Get more insights on - Mesenchymal Stem Cells