Researchers at the University of Birmingham have identified a new mechanism by which obesity may contribute to muscle loss in older adults, offering important insights into the condition known as sarcopenic obesity.
The study, published in the Journal of Cachexia, Sarcopenia and Muscle and delivered through the National Institute for Health and Care Research (NIHR) Birmingham Biomedical Research Centre (BRC) shows for the first time that extracellular vesicles — tiny particles released by fat tissue — can directly trigger muscle atrophy in human cells, providing new insight into how ageing and obesity interact to influence muscle loss.
Sarcopenic obesity, where excess body fat coexists with reduced muscle mass and strength, is an increasingly common condition in ageing populations and is associated with frailty, reduced mobility, and poorer overall health outcomes. It is estimated to affect around 11% of the population.
In the study, researchers found that extracellular vesicles released from obese adipose (fat) tissue — but not lean tissue — caused significant thinning of muscle fibres derived from older adults. This effect was driven by specific molecular cargo carried within the vesicles, particularly miR-150-5p, a microRNA which influences gene expression pathways involved in muscle maintenance.
Crucially, the researchers found that muscle cells derived from younger adults were resilient to these effects. Exposure to obese adipose tissue and its extracellular vesicles did not trigger muscle thinning in younger muscle cells, highlighting an age-dependent vulnerability.
