Changes in macrophage immunometabolism as a marker of skeletal muscle dysfunction across the lifespan

One of the most pronounced changes in the elderly is loss of strength and mobility due to the decline of skeletal muscle function, resulting in a multifactorial condition termed sarcopenia. Although significant clinical changes begin to manifest at advanced ages, recent studies have shown that changes at the cellular and molecular level precede the symptomatology of sarcopenia. By utilizing a single-cell transcriptomic atlas of mouse skeletal muscle across the lifespan, we identified a clear sign of immune senescence that presents during middle age. More importantly, the change in macrophage phenotype in middle age may explain the changes in extracellular matrix composition, especially collagen synthesis, that contributes to fibrosis and overall muscle weakness with advanced age. Our results show a novel paradigm whereby skeletal muscle dysfunction is driven by alterations in tissue-resident macrophages before the appearance of clinical symptoms in middle-aged mice, providing a new therapeutic approach via regulation of immunometabolism.

Automated summary

One of the most significant changes in the elderly is the loss of strength and mobility due to skeletal muscle decline, known as sarcopenia. Recent studies have found that cellular and molecular changes precede the clinical symptoms of sarcopenia. Using a single-cell transcriptomic atlas, researchers identified immune senescence in middle-aged mice, which may explain the changes in extracellular matrix composition and muscle weakness. This suggests a new therapeutic approach via regulation of immunometabolism.