Mesenchymal stem cells from biology to therapy

Abstract

Mesenchymal stem cells are as fascinating as they are enigmatic. They appear capable of performing a wide array of functions that cross skeletal biology, immunology and haematology. As therapeutics, mesenchymal stem cells or even just their secreted products may be used to regenerate tissue lost through injury or disease and suppress damaging immune reactions. However, these cells lack unique markers and are hard to identify and isolate as pure cell populations. They are often grown in laboratories using basic and undefined culture conditions. We cannot even agree on their name. While mesenchymal stem cells may lack the developmental understanding and defined differentiation hierarchies of their more illustrious stem cell cousins, they offer a compelling scientific challenge. In depth understanding of mesenchymal stem cell biology will enable us to exploit fully one of the most clinically valuable cell sources.

Keywords: cell therapy; extracellular vesicle; mesenchymal stem cell; mesenchymal stromal cells; regenerative medicine; tissue engineering.

Figure 1.. Activity in the research and clinical trial fields using MSCs.

(A) Number of publications listed on PubMed database (search term: ‘mesenchymal stem cells’ OR ‘mesenchymal stromal cells’) by year from 2000. (B) Clinical trials first posted (search term on ClinicalTrials.gov: ‘mesenchymal stem cells’ OR ‘mesenchymal stromal cells’) by year from 2000.

Figure 2.. Approaches to therapeutic exploitation of MSCs and their products.

MSCs can be applied by direct injection of cell suspensions or seeded onto biomaterial scaffolds as adhesion sites for local administration. MSC-derived EVs can be used in their naïve, unaltered state or engineered to carry specific cargos and/or cell-targeting motifs. Both modalities are applicable in tissue regeneration or immunomodulatory therapies.