SIRT1 and ischemia reperfusion injury: Dysregulation of Sirt1 is implicated in the pathogenesis of various diseases including PH[19].It was recently shown that Notch and Sirt1 signaling interact; indeed,notoginsenoside R1 significantly restored cerebral blood flow, improved mitochondrial energy metabolism, and promoted vascular regeneration by activating the NAMPT-NAD+-SIRT1 pathway and inhibiting Notch signaling after ischemia-reperfusion injury in rats, while Sirt1 inhibition partially reversed the modulatory effect of notoginsenoside R1 on Notch signaling [20].