Posted on Mar 17, 2018, 3 a.m.
Muscular function declines with age, this study shows how unexpected high numbers of mutations in stem cells of muscles impair cell regeneration, which may result in new therapies to build stronger muscles even in the elderly, as published in Nature Communications.
The fact that the natural process of aging impairs functions of skeletal muscles has already been long established. The number and activity of muscles’ stem cells decline with age is also known, the reason why is not fully understood.
Researchers investigated the number of mutations that accumulate in the muscle’s stem cells satellite cells and were shocked to find that a healthy 70 year old could accumulate over 1000 mutation in each stem cell in the muscle and that they were not random mutations, certain regions have more protection than others.
Natural cell division causes mutations, regions that are protected are important for function or survival of the cells, this study identifies that the protection declines with age, with the research being conducted using single stems cells cultivated to provide sufficient amounts of DNA for whole genome sequencing. This was achieved in skeletal muscle tissue to find that there is little overlap of mutations despite cells close proximity to each other representing complex mutational burden.
Researchers have been able to demonstrate that protection diminishes with age, indicating an impairment in the cell capacity to repair DNA, which should be able to be influenced with the development of new drugs and therapies.
Studies will continue to investigate whether physical activity can affect these numbers; if physical activity from a young age clears out cells with less mutations; and/or will it result in generation of a higher number of accumulated mutated cells? The aim is to discover if it is possible to influence individually the burden of mutations, which may be beneficial for the development of programs and therapies, specifically for the aging population.
This is a cooperative project between the researchers at affiliated institutes in Italy, Science for Life Laboratory, Linkoping University, Uppsala University, Stockholm University, and Karolinska Institutet.
Materials provided by Karolinska Institutet.
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Irene Franco, Anna Johansson, Karl Olsson, Peter Vrtačnik, Pär Lundin, Hafdis T. Helgadottir, Malin Larsson, Gwladys Revêchon, Carla Bosia, Andrea Pagnani, Paolo Provero, Thomas Gustafsson, Helene Fischer, Maria Eriksson. Somatic mutagenesis in satellite cells associates with human skeletal muscle aging. Nature Communications, 2018; 9 (1) DOI: 10.1038/s41467-018-03244-6