The return of young blood?
With age, muscle mass gradually decreases, muscles become weaker and lose the ability to recover from injuries. Researchers from the University of Pittsburgh Medical Center have identified an important mediator of youth in the muscles of mice, which one day can be used for muscle regeneration in the elderly. This mediator turned out to be extracellular vesicles, which, being essentially couriers, deliver genetic instructions for the expression of the "youth protein" klotho to muscle cells.
The results are an important step in understanding why the ability of muscles to regenerate decreases with age. Loss of muscle function and impaired muscle regeneration in old mice may be associated with "old" extracellular vesicles that carry fewer copies of the kloto gene than in young animals.
Researchers have suggested that extracellular vesicles of a young organism can be used as a therapeutic agent to counteract age-related muscle changes.
In numerous previous studies, it has been observed that the administration of blood taken from young mice to old mice leads to the restoration of "young" characteristics in cells and tissues (this effect has not been confirmed in humans). But until now it was unclear which components of young blood have such an effect.
In the new study, the group took blood from young mice, removed shaped elements and clotting factors from it, and injected the resulting serum into old mice with muscle damage. This led to enhanced regeneration of muscle tissue and restoration of muscle function in these rodents compared to control mice who received a placebo. After extracellular vesicles were removed, the rejuvenating properties of the serum were lost.
Focusing on extracellular vesicles, the researchers determined that they deliver genetic instructions in the form of matrix RNA (mRNA) encoding the anti-aging protein kloto to muscle progenitor cells – stem cells, from which skeletal muscle cells are formed. Extracellular vesicles obtained from old mice contained fewer copies of mRNA than in young mice, and therefore less actively induced muscle progenitor cells to produce this protein.
Based on the data obtained, "young" extracellular vesicles can be used to increase the regenerative capacity of muscles in the elderly and improve functional recovery after injuries.
One of the other areas in which the research team plans to go further is the development of extracellular vesicles carrying specific loads that will control the behavior of target cells in order to reverse other effects of aging, including cognitive impairment.
Article A.Sahu et al. Regulation of aged skeletal muscle regeneration by circulating extracellular vesicles is published in the journal Nature Aging.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru based on the materials of the University of Pittsburgh: Study identifies factor in 'young blood' that helps rejuvenate aged mouse muscle.