Exosomes carry key indicators of biological aging

A new research paper featured on the cover of Volume 17, Issue 8 of Aging (Aging-US) was published on July 30, 2025, titled "Exosomes released from senescent cells and circulatory exosomes isolated from human plasma reveal aging-associated proteomic and lipid signatures."

In this study, led by first authors Sandip Kumar Patel and Joanna Bons, along with corresponding author Birgit Schilling from The Buck Institute for Research on Aging, researchers found that exosomes-tiny particles released by cells-carry molecular signatures that indicate both biological aging and cellular senescence. These signatures include proteins, lipids, and microRNAs associated with inflammation, oxidative stress, and tissue remodeling. The findings could enhance our understanding of biological aging and help in developing future anti-aging therapies.

Senescence is a state in which cells stop dividing but remain metabolically active. These cells often release harmful substances, known collectively as the senescence-associated secretory phenotype (SASP), that can affect nearby tissues. This study shows that exosomes are an important component of this secretory profile.

The researchers analyzed exosomes from senescent human lung cells and from the blood plasma of both young and older adults. They identified over 1,300 proteins and 247 lipids within these particles. Many of these molecules were significantly altered with age.

"In parallel, a small human plasma cohort from young (20–26 years) and old (65–74 years) individuals revealed 1,350 exosome proteins and 171 plasma exosome proteins were altered in old individuals."

Exosomes from older individuals contained more inflammation-related proteins and fewer antioxidants, while those from senescent cells showed lipid changes associated with membrane integrity and cellular stress. These changes suggest that exosomes may play a role in spreading senescence to nearby cells, a process known as secondary senescence.

The study also identified distinct patterns in microRNAs-small molecules that regulate gene expression-found in the blood of older adults. Some of these, including miR-27a and miR-874, have previously been associated with cognitive decline and chronic illnesses, highlighting their potential as biomarkers for biological aging.

Although the study involved a limited number of samples, it provides strong early evidence that exosomes reflect the molecular changes associated with aging. By showing how these particles carry and possibly spread aging-related signals throughout the body, the research opens new possibilities for diagnosing and treating age-related diseases.