Derivatives of mesenchymal stromal cells: methods of preparation and scope of application in veterinary medicine (review)

Mesenchymal stromal cells (MSCs) are immature cells of the body that have the ability to proliferate into various functionally active cells. MSCs injected into the body have immunomodulatory, anti-inflammatory, stimulating, angiogenetic and regenerative properties 1, 3, 4. In addition to stromal cells, their components, conditioned media (CM) and exosomes, have therapeutic properties 6. CM are a combination of biomolecules and growth factors in the growth medium of cell cultures, it is obtained by centrifugation, fractionation and/or filtration, while the composition of CM depends on the duration of cultivation, the nutrient medium and additives used in cultivation, as well as the passage number and the conditions under which the cells were grown 7-10. Exosomes are extracellular vesicles secreted by cells with a diameter of 20 to 1000 nm, capable of encapsulating proteins and RNA, penetrating through the plasma membrane or binding to proteins on the surface of receptors, transporting various substances to target cells 12. Exosomes are obtained using ultracentrifugation, ultrafiltration and precipitation methods 13.MSC components are used in various fields of veterinary medicine. For example, an air-conditioned environment is used in the treatment of wounds and ulcers. A study by Bussche L., Harman R.M. et al. (2015) shows that CM obtained from horse MSCs stimulates fibroblast migration in vitro, as well as increases gene expression levels that have a positive effect on wound healing 18, and cell-free therapy helps to reduce the area of the wound surface by 98.47% 19. Conditioned environments are used in the treatment of fractures and diseases of the musculoskeletal system. Thus, exosome transplantation to the fracture site stimulates osteogenesis and angiogenesis 22 and promotes faster bone fusion 23. Also, some authors note a beneficial effect in the treatment of osteoarthritis with exosomes 24, 25. In addition, the researchers note a positive effect when using MSCs components in the treatment of allergic rhinitis, mastitis and endometritis, spinal cord injuries, as well as cryopreservation of spermatozoa.