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- Instead of strength: "mobility hormone" will save astronauts from muscle atrophy
Instead of strength: "mobility hormone" will save astronauts from muscle atrophy
Russian scientists have made a discovery that could change approaches to maintaining the health of astronauts and patients with limited mobility. They managed to prove that the MOTS-c peptide, called the "mobility hormone", is able to protect muscles from exhaustion and loss of endurance in the absence of physical exertion. In an experiment on rats that were artificially created in zero gravity, injections prevented a decrease in muscle mass, while in animals without treatment, these indicators decreased dramatically. This opens the way to the creation of drugs that will help maintain muscle health during long-term space flights.
What is Motility Hormone?
Astronauts' muscle mass decreases by 20% in two weeks in low gravity. Similar atrophy, or muscle wasting, is experienced by patients who are forced to stay in bed for a long time, elderly and even healthy people who are faced with a sharp decrease in physical activity. In addition to volume and mass, muscles without regular training also lose endurance. This is due to a change in the type of fibers that make up the muscles. Scientists from the Institute of Biomedical Problems of the Russian Academy of Sciences have shown in an experiment on rats that the introduction of the MOTS-c peptide, which is also called motility hormone, prevents muscle atrophy, the transformation of slow fibers into fast fibers and a decrease in endurance after a week without exercise.
A Wistar rat from the project experiment
As the experts explained, this peptide is produced by the "energy stations" of cells — mitochondria — during periods of physical activity. In the absence of prolonged and constant physical exertion, it is not released, which is why mitochondria work worse, muscles weaken, there are fewer slow fibers, and a person can get tired even from a short walk.
Scientists conducted experiments on the introduction of MOTS-c on rats. For this purpose, the animals were divided into three groups of eight individuals. The rats of the control group lived in ordinary laboratory cages. Animals of other groups were kept in special cages for unloading their hind limbs — they were suspended so that their hind legs did not touch the support. Because of this, their flounder muscles— the slow muscles involved in walking—were completely deprived of exercise, as in zero gravity. At the same time, the animals could move around the cage in any direction using only their front paws. Rats of one of the groups received artificially synthesized rat MOTS-c daily under conditions of such unloading.
After seven days of the experiment, the scientists noted that the peptide content in the muscles of animals that did not receive the substance during unloading decreased by 60% compared with the control group. The authors also examined the flounder muscles of rats. It turned out that the weekly "weightlessness" reduced the volume of fast fibers by a third in both groups with unloading compared to the control group. However, the volume of slow fibers in rats treated with MOTS-c decreased by only 15-20%, while in animals without treatment this figure reached 30-35%.
— The problem of fatigue and loss of muscle mass is relevant for all people with insufficient activity levels, which is almost a third of the adult population of the world. We plan to investigate other factors that affect the structure and function of muscle tissue. In the next project, we will look at how the calcium content in muscles affects their endurance, as well as the functioning of muscle fibers and their components," said Kristina Sharlo, senior researcher at the Laboratory of Myology at the Institute of Biomedical Problems of the Russian Academy of Sciences.
Muscle recovery with low mobility
Scientists assessed the endurance of rats using a special test in which the muscle was forced to contract with the maximum possible intensity using an electric current. The study showed that in animals taking the peptide, endurance remained at a normal level, and decreased by half when unloading without intervention.
In addition, the authors analyzed the content of biomarker substances in the muscle, which indicate the growth or destruction of muscles, as well as the activity of mitochondria. It turned out that the peptide made it possible to completely preserve the normal functioning of mitochondria, which is necessary for cells to generate energy.
Currently, research is focused on laboratory animals, but potentially, if the compound is effective for humans, it could help develop drugs to protect the muscles of astronauts in low gravity, bedridden patients, and other people with low physical activity, such as the elderly or sedentary workers.
Staff of the Laboratory of Myology at the Institute of Biomedical Problems of the Russian Academy of Sciences under the leadership of Professor Boris Stevovich Shankman
This peptide is a promising candidate for space medicine, said Albert Rizvanov, head of the Center of Excellence "Personalized Medicine" at Kazan (Volga Region) Federal University.
— This is especially important for long-term space flights and for patients with prolonged bed rest, when the risk of muscular atrophy increases dramatically. So far, the effectiveness has been confirmed only in short-term animal experiments. Long-term clinical trials are needed for human use, which will evaluate not only the effectiveness, but also safety, including possible effects on metabolism and the functioning of other organs. For example, the effect on glucose metabolism, heart function, or hormonal balance, which the animals might not have manifested," the scientist said.
When inactive, the hormone myostatin is released in the muscles, and it aims to destroy muscle tissue, triggering the degradation of muscle fiber, Mikhail Bolkov, a researcher at the Institute for the Study of Aging at the Russian Gerontological Research and Clinical Center of the Russian National Research Medical University named after N.I. Pirogov, explained to Izvestia. If the muscles are overtrained, it removes excess fiber.
— But the problem is that in our society, the problem is not overtraining, but undertraining. It is necessary to constantly maintain muscle tone, so exercise or walking is necessary. And the MOTS-c substance, which is secreted in the mitochondria, blocks myostatin and acts protectively for muscles," the scientist said.
It is worth remembering that about 70% of the results in animal models are not confirmed, said NTI Helsnet market expert, creator of the Nestarenie IT service.Expert Dmitry Veremeenko.
— Differences in human and rodent biology only exacerbate this problem. Therefore, human studies are not a formality, but a critical stage for evaluating the actual effectiveness and safety," the expert said.
The results of the study, supported by a grant from the Russian Science Foundation (RSF), are published in the Journal of Muscle Research and Cell Motility.
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