New Insights into the Composition and Efficacy of Stem Cell Therapies

According to research from the University of California San Diego, two commonly used stem cell therapies contain entirely different types of cells, despite their frequent interchange. The findings cast doubt on the "one-cell-cure-all" paradigm that currently governs orthopaedic stem cell therapies and emphasizes the need for a more thorough characterization of injectable stem cell therapies before their commercialization for use in human patients.

The researchers examined cell populations obtained from the same subjects' autologous bone marrow aspirate concentrate (BMAC) and adipose-derived stromal vascular fraction (ADSVF).

Both of these injectable therapies—bone marrow in BMAC and adipose tissue (fat) in ADSVF—are derived from the patient's own cells and are believed to contain mesenchymal stem/stromal cells (MSCs), which are cells with the capacity to differentiate into muscle, bone, and other connective tissues. These therapies share many similarities.

The two treatments are commonly marketed as interchangeable "stem cell therapies" due to their similarities. They are used to treat a variety of skin and musculoskeletal conditions, especially in professional athletes. Nevertheless, not much work has been done to date to try and define the makeup and underlying biology of these two treatments.

According to the researchers, this lack of knowledge has hindered thorough clinical investigations into the recommended dosages for these therapies and fostered false information in the treatments' marketing within the $11.9 billion stem cell industry.

The researchers filled this vacuum by examining 62 BMAC cell populations and 57 ADSVF populations to produce a cellular atlas that lists the cell types involved in each therapy and the genes and proteins that are active in these cells.

Their atlas showed that neither therapy had similar "stem cell" types overall and that MSC concentrations in BMAC formulations were incredibly low. The compositions of the two treatments were actually very different; ADSVF was primarily composed of connective tissue cells, whereas BMAC was primarily composed of red and white blood cells.

Furthermore, a number of proteins linked to regenerative function were either absent or present in incredibly low amounts in both treatments, raising concerns about their overall efficacy and mechanisms of action.

The results indicate that further clarification of the active ingredients in biologic therapies such as BMAC and ADSVF is necessary, in addition to offering a valuable resource for researchers. Additionally, they recommend that the field shift to more standardized cell therapies, where the concentrations of proteins and the amounts of cells that are clinically necessary have been precisely measured.