Why Do Muscles Age? New Study Answers the Regeneration Puzzle
Cornell University researchers have created a detailed understanding of how muscles lose their ability to regenerate as they age, using mice as a model. They identified 29 cell types and found that immune cells and muscle stem cells behave differently in older mice, leading to discoordination in muscle repair.
As muscles age, their cells lose the ability to regenerate and heal after injury. Now, Cornell University researchers have created the most comprehensive portrait to date of how that change, in mice, unfolds over time.
“The fundamental question that drove the initial study was really a question that had perplexed the skeletal muscle biology community,” said Ben Cosgrove, associate professor of biomedical engineering and the paper’s senior author. “Does the decline in regeneration seen in old muscles come from changes to the stem cells that drive the repair process themselves, or does it come from changes in the way that they are instructed by other cell types?”
In the study published in Nature Aging, researchers sampled cells from young, old, and geriatric mice at six time points after inducing injury via a variant of snake venom toxin. They identified 29 defined cell types, including immune cells that exhibited differences in their abundance and reaction time between age groups, and muscle stem cells that self-renew in youth but stall out as muscles age.
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Paper Reference: “Transcriptomic analysis of skeletal muscle regeneration across mouse lifespan identifies altered stem cell states” by Lauren D. Walter, Jessica L. Orton, Ioannis Ntekas, Ern Hwei Hannah Fong, Viviana I. Maymi, Brian D. Rudd, Iwijn De Vlaminck, Jennifer H. Elisseeff and Benjamin D. Cosgrove, 22 November 2024, Nature Aging .
DOI: 10.1038/s43587-024-00756-3