Research led by cardiologist Jürg Beer at the University of Zürich highlights the impact of aging gut microbiomes on vascular senescence. Elevated microbial metabolites phenylacetic acid (PAA) and phenylacetylglutamine (PAGln) were found to accelerate endothelial cell aging and reduce vascular function in animal and human studies. These findings provide mechanistic insight into microbiome-host interactions contributing to cardiovascular disease and open avenues for potential therapeutic interventions targeting microbial metabolites.