Over the past decade, stem cell research has provided new avenues for deeper investigation into tissue repair and aging processes, as well as regenerative medicine methods. One of the major players in such research endeavors are mesenchymal stem cells (MSC), also known as mesenchymal stromal cells. MSC are typically found in bone marrow, adipose, placental, and umbilical cord tissues1 and are a type of adult stem cell. In vivo, these cells are headquartered in special microenvironments or “niches” in the body where they remain quiescent until triggered to self-renew to maintain their stem cell population or to differentiate into specialized daughter cell types. MSC may also remain quiescent for extended periods of time. Unlike pluripotent stem cells (e.g., embryonic stem cells) that can specialize into numerous cell types, MSC are non-hematopoietic, multipotent stem cells and thus possess a limited differentiation capacity that yields fewer specified cell types. MSCs produce bone, cartilage, fat, and stromal cell types when required to facilitate tissue growth or repair2. As such, regenerative medicine and biomedical research often employ human MSCs (hMSC) in studies on connective tissue repair3, immune response-based diseases4, and inflammatory diseases5 to better understand etiology and assess treatment approaches.
The use of hMSCs in research, however, is not without its particular challenges. Like all adult stem cells, hMSC populations are found in small quantities in situ and can be technically challenging to isolate from tissue. Moreover, freshly harvested hMSC populations may also contain other, off-target cell types. Thus, hMSCs must be purified and expanded in vitro to reach sufficient quantities for experimentation. This must be judiciously done as differentiation potential and genomic integrity begin to wane around 5-12 passages6,7. Researchers may use the phenotypic and functional assessments described here to assist in successful purification and correct identification of hMSC identity. When combined with a high-performance culture medium, such methods encourage hMSC culture integrity necessary to generate good-quality, reproducible research, and cell-based therapy.