CXCL12 and endothelial dysfunction: Overall, these findings distinguish senescent endothelial cells as senolytic targets, establish the circulating SASP milieu as a driver of age-related endothelial dysfunction, and identify CXCL12 as a specific circulating SASP factor that mediates endothelial cell senescence and dysfunction with aging that can be modulated with fisetin senolytic treatment.