Given that HSP70 abundance and location are tightly associated with its cytoprotective effect against oxidative stress, a stressful condition contributing to endothelial dysfunction [3–5], we speculate that antioxidant activity of Nar may be related to its regulation on HSP70, by which Nar improves diabetic- or hyperglycemia-induced impairment of endothelial function. Here, HSPA1A is linked to endothelial dysfunction.