Uncontrolled accumulation of methylglyoxal (MG) and reactive oxygen species (ROS) occurs in hyperglycemia-induced endothelial dysfunction associated with diabetes. Resveratrol (RSV) protects the endothelium upon high glucose (HG); however, the mechanisms underlying such protective effects are still debated. Here we identified key molecular players involved in the glycative/oxidative perturbations occurring in endothelial cells exposed to HG. In addition, we determined whether RSV essentially required SIRT1 to trigger adaptive responses in HG-challenged endothelial cells. We used primary human umbilical vein endothelial cells (HUVECs) undergoing a 24-h treatment with HG, with or without RSV and EX527 (i.e., SIRT1 inhibitor). We found that HG-induced glycative stress (GS) and oxidative stress (OS), by reducing SIRT1 activity, as well as by diminishing the efficiency of MG-and ROS-targeting protection. RSV totally abolished the HG-dependent cytotoxicity, and this was associated with SIRT1 upregulation, together with increased expression of GLO1, improved ROS-scavenging efficiency, and total suppression of HG-related GS and OS. Interestingly, RSV failed to induce effective response to HG cytotoxicity when EX527 was present, thus suggesting that the upregulation of SIRT1 is essential for RSV to activate the major antiglycative and antioxidative defense and avoid MG-and ROS-dependent molecular damages in HG environment.2 of 23 tightly link GS and OS [5,7,12]. This link is strengthened by the fact that AGEs are often able to activate powerful ROS-generating pro-inflammatory pathways [7,13].Given the importance of redox signaling and the pivotal role of AGEs in the pathogenesis of diabetes-related vascular complications, a great interest is rising in finding interventional strategies aimed at improving antioxidative efficiency and antiglycative defense in the endothelium exposed to high glucose (HG) [14][15][16][17].Resveratrol (trans-3,5,4 -trihydroxystilbene; RSV), a plant-derived low molecular weight phytoalexin, is a nutraceutical agent through which redox-based pathologies (e.g., cardiovascular diseases, glucose intolerance, and insulin resistance) may be treated [18,19]. Some animal-based studies have shown anti-hyperglycemic properties of RSV, and patients with type 2 diabetes mellitus (T2DM) exhibited reduced oxidative stress, as well as improved insulin sensitivity and cardiovascular function after RSV treatment [20][21][22][23]. Moreover, RSV supplementation was demonstrated to ameliorate diabetes-related deterioration of systemic redox milieu and brain antioxidant capacity [24][25][26]. The beneficial bioeffects of RSV may arise from direct antioxidant properties and/or activation of endogenous self-defense mechanisms of the host cells [19]. The latter effects may be due to enzyme modification, direct upregulation of redox-responsive genes, and activation of sirtuin 1 (SIRT1), an important member of the family of NAD + -dependent class III deac(et)ylases [27]. As a key protein governing metabolic adaptation, D...