Participation of Mesenchymal Stromal Cells in Muscle Tissue Regeneration

Mesenchymal stromal cells (MSCs) are considered universal regulators of tissue homeostasis. They are promising for the repair of skeletal muscles after injuries and diseases. Although the main participants of muscle regeneration are myosatellites, resident MSCs and those sent from the bone marrow in response to damage are also involved. MSCs are capable of myogenic differentiation and fusion with muscle cells. However, the paracrine secretion of regulatory molecules by MSCs is more important for regeneration. They promote the survival, proliferation, and differentiation of cells in the injured muscle. Factors secreted by MSCs affect all stages of the reparative process. This allows MSCs to be used for the complex delivery of bioactive molecules. The prospects for the use of MSCs were demonstrated in various experimental models of muscle damage, such as mechanical and chemical injuries, atrophy, ischemia, and genetically determined muscular dystrophy. Improvement of MSC delivery to the muscle can increase the efficiency of regeneration. Cell transplantation on artificial scaffolds makes it possible to achieve this goal. The ultrasound treatment of muscles also concentrates MSCs at the injury site. Magnetic cells delivery is another way to increase their concentration. The paracrine activity of MSCs can be enhanced via preconditioning with different stimuli, which changes the secretory profile of cells in the desired direction. Genetic modification of MSCs also increases their therapeutic potential. MSCs produce extracellular vesicles with regulatory molecules such as miRNAs. The use of these vesicles and molecules is a new area of regenerative medicine. MSC activation stimulates tissue regeneration due to internal reserves and can therefore be considered a tool of in vivo tissue engineering.