Characterization of extracellular vesicles from equine bone marrow-derived mesenchymal stem cells and their therapeutic potential

Tendinopathy is a common tendon disorder caused by overuse injury, resulting in chronic pain and impaired biomechanical tendon properties. Current treatments do not effectively restore tendon function, highlighting the need for better options. Regenerative medicine, which aims to restore damaged tissues and organs, offers potential solutions using approaches like stem cell therapy. Mesenchymal stem cells (MSCs) are a promising strategy due to their ability to differentiate into different cell types and secrete bioactive molecules. Recent studies suggest that the paracrine effect of MSCs, specifically their secretome (which includes growth factors, cytokines, and extracellular vesicles), plays a crucial role in tissue regeneration. This study focuses on evaluating the therapeutic effect of the secretome of equine MSCs and its sub-fractions, extracellular vesicles (EVs), and soluble proteins, on inflamed tenocytes. The author emphasizes the need for standardized methods for isolating and characterizing EVs in order to develop EV-based regenerative therapies. The similarity between tendinopathies in horses and humans suggests that the findings may have implications for both species. Various studies have shown the regenerative potential of MSC-conditioned media (CM) and EVs in tendon repair, promoting cell proliferation, tissue architecture restoration, and the expression of genes related to collagen and tendon matrix formation. However, the exact mechanisms of action and the specific bioactive molecules responsible for therapeutic effects remain unclear. Standardized purification and analytical methods are crucial for understanding and developing reliable EV-based regenerative therapies. The study also highlights the importance of optimal donor cells, their preconditioning status, and the age or passage number of MSCs in the secretome's therapeutic efficacy. Allogeneic MSCs offer a cell-free, off-the-shelf treatment option with scalable and standardized manufacturing. Additionally, future studies should focus not only on quantitative parameters but also on qualitative aspects, such as the identification of specific components and their regenerative effects. Overall, this research contributes to understanding the therapeutic potential of MSC secretomes and their sub-fractions in tendon repair, emphasizing the need for standardized methods, characterization, and dosage determination to advance EV-based regenerative therapies.