Abstract
As global populations age, chronic disease burden rises across multiple organ systems. This special issue treats aging as a multi-system process shaped by biology, environment, and behavior. Across 30 original studies and reviews, the collection centers on shared mechanisms of decline, including mitochondrial dysfunction, circadian disruption, hypoxia, inter-organ signaling, and cellular senescence. The articles track how these processes change across tissues and across time. Multiple contributions link systemic changes to tissue-level dysfunction. Vascular, immune, and metabolic shifts appear repeatedly as upstream drivers. The issue also emphasizes local context. Tissue microenvironments shape how the same systemic stressor produces different outcomes, which helps explain heterogeneity in aging trajectories. Several papers move toward translation. They propose biomarkers and diagnostic strategies aimed at earlier detection, risk stratification, and longitudinal monitoring. The strongest translational value comes when authors connect a proposed tool to a defined endpoint and a defined use case, rather than broad "precision" framing. Overall, the issue argues for tighter alignment between mechanism and measurable outcomes. The collection also highlights critical areas where further validation and integration are needed to support clinical translation.