Preserve youth: stem cells instead of physical education
Exercise activates stem cells in muscles
Nanonewsnet based on materials from the University of Illinois at Urbana-Champaign:
Exercise triggers stem cells in muscle
Scientists from the University of Illinois have found that adult stem cells present in muscles are able to actively respond to mechanical action – a discovery that can link a healthy state of muscles with physical exercise. The results obtained will contribute to the development of new treatment methods in which stem cells will be used not only for accelerated rehabilitation after muscle injuries, but also to prevent age-related loss of muscle mass, and possibly for its recovery.
It is well known that the preservation of skeletal muscle mass plays a key role in overall health and quality of life. A decrease in the number of contractile proteins and the subsequent reduction in the size of muscle fibers as a result of illness, immobility or with age can lead not only to a decrease in physical strength, but also to an increased risk of developing metabolic diseases, including a predisposition to obesity, diabetes and cardiovascular diseases. Physical activity or rehabilitation therapy can preserve muscle mass and muscle function. Therefore, the identification of the main mechanisms underlying beneficial adaptations to physical activity can provide crucial information for the development of effective molecular or cellular therapy.
It is known that mesenchymal stem cells (MSCs) in skeletal muscles play an important role in their recovery after non-physiological injuries, mainly in response to chemical injections that cause significant damage to muscle tissue and inflammation. The aim of a group of scientists led by Professor Marni Boppart was to investigate whether mesenchymal stem cells react to stress during physical exertion and, if so, how.
"Since physical exertion can lead to injury as part of the remodeling process after mechanical stress, we were interested in whether the accumulation of mesenchymal stem cells is a natural reaction to exercise and whether these cells contribute to regeneration and the growth process occurring in the post–workout period," Professor Boppart comments on the purpose of the study.
Scientists have found that MSCs in muscles are very sensitive to mechanical stress. They recorded an increase in their number in the muscles of mice after intense physical activity. It also turned out that, although mesenchymal stem cells do not directly contribute to the creation of new muscle fibers, they secrete growth factors that stimulate the fusion of other cells and the formation of new muscles, providing a cellular basis for improving their condition after exercise.
A key element of Professor Boppart's method was the isolation of cells from the muscles of mice after physical exertion, when MSCs begin to secrete beneficial growth factors. Then the cells were labeled with a fluorescent marker and injected into other mice, which allowed scientists to study the interaction of MSCs with other cells that form muscle mass.
Mesenchymal stem cells (green) accumulate in skeletal muscles after physical exertion
and release growth factors that stimulate regeneration. (Photo: Marni Boppart)
In addition to studying the behavior of cells in a living organism, scientists have studied the reaction of cells to load on various substrates. They found that MSCs are very sensitive to mechanical effects from the environment, and muscle tension has a significant effect on the activity of these cells.
"The results obtained are important because we have identified adult stem cells in muscles that can become the basis for a healthy muscle condition maintained through exercise and accelerate muscle recovery through rehabilitation motor therapy," says Professor Boppart. "In addition, the fact that during exercise, muscle MSCs are able to release high concentrations of growth factors into the circulatory system made us wonder if they do not provide a crucial link between improving the health of the whole body and daily physical activity."
In the near future, researchers plan to determine whether mesenchymal stem cells contribute to the reduction of muscle mass that occurs throughout a person's life. According to preliminary data, the deficiency of MSCs increases with age in the muscles. Scientists hope that they will be able to develop a combined treatment method that will use strategies to prevent age-related muscle loss based on both a molecular and cellular approach.
"Although exercise is the best strategy for preserving muscles during aging, physical activity is simply not available to some people," says Boppart. "Disability can limit the possibilities of muscle growth. We are working hard to understand how best to use these cells to effectively preserve muscle mass in the face of its atrophy."
An article about the study of Eccentric Exercise Facilitates Mesenchymal Stem Cell Appearance in Skeletal Muscle is published in the open access journal PLoS One.
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13.02.2012