Mesenchymal stem cells (MSCs) are “hot” in biomedical research these days because they are multipotent stem cells that can be found in adipose (fat) tissue, umbilical cord blood and tissue, placenta, and bone marrow. MSCs behave like stem cells and, under specific conditions, can be induced to differentiate into specific cell types like adipocytes, chondrocytes or osteocytes. MSCs appear to be an exceedingly valuable potential source of stem cells for therapeutic use and are being studied in many diverse areas of biomedical research. One could imagine that in the future MSCs could be obtained from an individual, purified and induced to differentiate into a specific cell population and then be infused back into the same individual as a form of immunotherapy.

Obtaining a pure population of MSCs is critical to any experiment or application that uses these cells. Cell sorting by flow cytometry (FACS) is a precise and rapid way to purify MSCs and has been used successfully for preclinical and research applications. MSCs are sorted using a panel of fluorescent antibodies that can select for this rare and unique cell population. MSCs can be isolated from human samples and from other species like dog and horse. MSCs across species have similar cell surface markers, so similar antibody panels could potentially be used for sorting.

MSCs are an extremely rare population, so early efforts to isolate these samples relied on imprecise technology like cell adhesion. In this era of polychromatic FACS, rare populations like MSCs can be isolated and sorted precisely using antibody panels with more than 12 different fluorochromes. FACS instrumentation are also equipped to handle large sample volumes at high speed, which assures that a reasonable number of viable MSCs will be yielded from a sort and can be used for downstream studies.

If you are considering using MSCs in your next experiment, consider the rarity of these cells and think about using cell sorting so you can feel assured you have a pure population of MSCs.