Mesenchymal stromal/stem cells or MSCs are widely used by unproven clinics, but MSC research also suggests real promise in specific areas. Clinics mainly use adipose MSCs (often called SVF) or bone marrow MSCs. However, umbilical cord MSC preparations are getting more popular too. Many questions swirl around the use of MSCs including what exactly are in these cellular preps and how many stem cells they contain. Some clinics tout both adipose and marrow MSCs or even mix the two. Other clinics focus primarily on just one or the other, and then criticize the type they aren’t using.
A new paper analyzing adipose and marrow MSCs addresses some of these questions and raises big concerns about clinic applications.
![MSC single cell transcriptome, MSC](https://i0.wp.com/ipscell.com/wp-content/uploads/2024/07/MSC-single-cell-transcriptome.png?resize=713%2C666&ssl=1)
MSC analysis points to challenges
Comparative single-cell transcriptional and proteomic atlas of clinical-grade injectable mesenchymal source tissues, Science Advances. In this piece, the team found some very concerning attributes of common marrow and fat MSC preparations. From a news item on the work:
“Their atlas revealed that MSC concentrations in BMAC formulations were extremely low, and that overall, there were no comparable “stem cell” types in both therapies. In fact, the two treatments had very different compositions; BMAC was composed mainly of red and white blood cells, and ADSVF was composed mainly of connective tissue cells.”
In other words, marrow and adipose MSC preps often don’t have many stem cells in them. It may be important therapeutically to isolate the actual stem and precursor cells out of the cellular mixtures prior to use if you are invoking a stem cell-based mechanism. These types of MSC preps are also quite distinct from each other. You’ll also note in the figure panel above from the paper the MSCs are off in a tiny cluster (red box) in the bottom right all by themselves. In Fig. 2B, cultured MSCs are also shifted away from the primary MSCs. Go to the paper to see this. Other challenges include quantifying MSCs and their relative scarcity in tissue preps.
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