Equine mesenchymal stem cell variability: a review of influencing factors and clinical potential

The application of mesenchymal stem cells (MSCs) in equine medicine has attracted growing attention because of their potential to treat various diseases. This review introduces some fundamental concepts of MSCs, advances of MSC-based therapies and the potential of MSC-derived extracellular vesicle based therapies. The advantages and limitations of autologous and allogeneic MSCs are discussed. An overview of factors influencing MSC variability is provided, including harvest site, donor signalment and replicative senescence as primary areas of focus, as they critically influence the biological properties and therapeutic efficacy of MSCs. The potential of MSCs to promote tissue regeneration and immune regulation in horses with a range of disorders is also summarised. Several research gaps are identified, including the absence of standardised protocols for MSC isolation and culture, limited understanding of the molecular mechanisms of MSC and the scarcity of clinical trials evaluating MSCs and extracellular vesicles under optimal therapeutic conditions. These gaps underscore the need for further investigation to advance their clinical translation in equine medicine.