Protective Effects of Antioxidant Polyphenols against Hyperglycemia‐Mediated Alterations in Cerebral Endothelial Cells and a Mouse Stroke Model

Scope Hyperglycemia alters cerebral endothelial cell and blood‐brain barrier functions, aggravating cerebrovascular complications such as stroke during diabetes. Redox and inflammatory changes play a causal role. This study evaluates polyphenol protective effects in cerebral endothelial cells and a mouse stroke model during hyperglycemia. Methods and results Murine bEnd.3 cerebral endothelial cells and a mouse stroke model are exposed to a characterized, polyphenol‐rich extract of Antirhea borbonica or its predominant constituent caffeic acid, during hyperglycemia. Polyphenol effects on redox, inflammatory and vasoactive markers, infarct volume, and hemorrhagic transformation are determined. In vitro, polyphenols improve reactive oxygen species levels, Cu/Zn superoxide dismutase activity, and both NAPDH oxidase 4 and nuclear factor erythroid 2‐related factor 2 (Nrf2) gene expression deregulated by high glucose. Polyphenols reduce Nrf2 nuclear translocation and counteract nuclear factor‐ĸappa B activation, interleukin‐6 secretion, and the altered production of vasoactive markers mediated by high glucose. In vivo, polyphenols reduce cerebral infarct volume and hemorrhagic transformation aggravated by hyperglycemia. Polyphenols attenuate redox changes, increase vascular endothelial‐Cadherin production, and decrease neuro‐inflammation in the infarcted hemisphere. Conclusion Polyphenols protect against hyperglycemia‐mediated alterations in cerebral endothelial cells and a mouse stroke model. It is relevant to assess polyphenol benefits to improve cerebrovascular damages during diabetes. Hyperglycemia induces oxidative stress and inflammation, promoting cerebral endothelial dysfunction and vascular disorders such as stroke. This study evaluates the protective effects of Antirhea borbonica polyphenols and caffeic acid in cerebral endothelial cells and a mouse stroke model exposed to hyperglycemic condition. Data show that polyphenols improve redox, pro‐inflammatory, and vasoactive markers, and decrease cerebrovascular damages aggravated by hyperglycemia.