Abstract
Background:
Extracellular vesicles (EVs) play a pivotal role in driving aging, serving as vehicles for the transmission of aging-related signals. Decay-accelerating factors (DAFs), also known as CD55, a crucial complement regulator, exhibits age-associated alterations, yet its expression on circulating EVs remains poorly characterized. This study aims to investigate differences in plasma EVs and CD55 positive EVs concentrations in younger and older adults, and explore their correlations with age and blood glucose levels.
Methods:
In this study, 40 older adults (≥65 years) undergoing routine physical examinations at Beijing Jishuitan Hospital and 40 gender-matched younger adults (<65 years) were enrolled prospectively. Blood glucose levels were measured using the standard glucose oxidase method. Circulating EVs concentrations were quantified by flow cytometry, including circulating total EVs, endothelial EVs (EEVs), platelet EVs (PEVs), red blood cell EVs (REVs), lymphocyte EVs (LEVs), monocyte EVs (MEVs), neutrophil EVs (NEVs), white blood cell EVs (WEVs), and CD55-positive EVs.
Results:
Compared to younger adults, older adults exhibited significantly lower concentrations of LEVs, MEVs, NEVs, and WEVs (p < 0.05). Concentrations of CD55 positive EVs, including CD55+EEVs, CD55+PEVs, CD55+LEVs, CD55+MEVs, CD55+NEVs, and CD55+WEVs, were markedly reduced in older adults (p < 0.05). Notably, CD55+PEVs showed the strongest negative correlation with age (r = - 0.6228, p < 0.001). Furthermore, significant inverse correlations were found between blood glucose levels and concentrations of CD55+EEVs (p = 0.001), CD55+PEVs (p = 0.006), CD55+LEVs (p < 0.001), CD55+MEVs (p = 0.001), and CD55+WEVs (p = 0.003).
Conclusion:
Our findings indicate significant differences in plasma EVs subtypes between older and younger adults and demonstrate robust negative correlations between CD55+ EVs subtypes and both aging and elevated glucose levels. Thus, these results suggest CD55+ EVs as a critical contributor to metabolic disorders in aging, offering potential risk assessment and monitoring strategies in older populations.