MMSCs

MMSCs, or multipotent mesenchymal stromal cells, are a heterogeneous population of adult stem cells found in bone marrow and other tissues such as adipose tissue, umbilical cord, dental pulp, and synovium. They are capable of differentiating into mesenchymal lineages, including osteoblasts, chondrocytes, and adipocytes, under appropriate conditions, and they can participate in tissue repair via paracrine signaling and immunomodulation. In culture, MMSCs are typically plastic-adherent and display a common set of surface markers: positive for CD105, CD73, and CD90; negative for hematopoietic and endothelial markers such as CD45, CD34, CD14 or CD11b, CD79a or CD19, and HLA-DR.

MMSCs secrete a range of cytokines and growth factors, modulate immune cell activity, and can influence inflammation, angiogenesis, and remodeling. They are used in research and clinical trials for regenerative medicine and immune-related conditions, including graft-versus-host disease, orthopedic injuries, and cardiovascular diseases. However, they are a heterogeneous group, and there is ongoing discussion about terminology and standardization of isolation, expansion, and potency assays. Differences among tissue sources, donor age, and culture conditions can influence function.

Regulatory agencies require robust characterization and safety assessment for therapeutic applications. Long-term safety, potential for unwanted differentiation, and variability remain considerations. Ongoing work aims to standardize nomenclature, characterization panels, and potency measures to enable reproducible research and clinically meaningful applications.