SIRT1 and aneurysm: Despite the emerging evidence showing that SIRT1 (Sirtuin 1) reduction in VSMCs facilitated Ang II-induced vascular aging and aneurysm formation [9] and the accumulation of SM22α promoted Ang II-induced VSMC senescence through suppressing Mdm2-mediated ubiquitination and degradation of p53 [10], the molecular mechanisms whereby chronic Ang II stimulation induces VSMC senescence remain incompletely understood.