The glucagon like peptide-1 receptor (GLP-1R) agonist liraglutide attenuates induction of plasminogen activator inhibitor type-1 (PAI-1) and vascular adhesion molecule (VAM) expression in human vascular endothelial cells (hVECs) in vitro and may afford protection against endothelial cell dysfunction (ECD), an early abnormality in diabetic vascular disease. Our study aimed to establish the dependence of the in vitro effects of liraglutide on the GLP-1R and characterise its in vivo effects in a mouse model of ECD. In vitro studies utilised the human vascular endothelial cell line C11-STH and enzyme-linked immunosorbent assays (ELISA) for determination of PAI-1 and VAM expression. In vivo studies of vascular reactivity and immunohistochemical analysis were performed in the ApoE -/-mouse model. In vitro studies demonstrated GLP-1R-dependent liraglutide-mediated inhibition of stimulated PAI-1 and VAM expression. In vivo studies demonstrated significant improvement in endothelial function in liraglutide treated mice, a GLP-1R dependent effect. Liraglutide treatment also increased endothelial nitric oxide synthase (eNOS) and reduced intercellular adhesion molecule-1 (ICAM-1) expression in aortic endothelium, an effect again dependent on the GLP-1R. Together these studies identify in vivo protection, by the GLP-1R agonist liraglutide, against ECD and provide a potential molecular mechanism responsible for these effects.

Background: Sodium glucose transporter type 2 inhibitors may reduce cardiovascular events in type 2 diabetes. Our study aimed to determine the effect of the sodium glucose transporter type 2 inhibitor dapagliflozin on endothelial cell activation, vasoreactivity and atherogenesis using in vitro and in vivo models and identify associated molecular mechanisms. Methods:In vitro studies utilised human vascular endothelial cells stimulated with tumour necrosis factor α or hyperglycaemic conditions. In vivo studies were performed in C57Bl/6J mice to evaluate direct vasorelaxation responses evoked by acute dapagliflozin administration and acute vaso-protective effects of dapagliflozin on hyperglycaemia-induced endothelial dysfunction. Adult and aged Apolipoprotein E-deficient mice maintained on a high-fat diet were used to investigate endothelial-dependent vascular reactivity and atherogenesis. Dapagliflozin treatment (1.0 mg/kg/day) was administered for 4 weeks. Results:In vitro studies demonstrated dapagliflozin-mediated attenuation of tumour necrosis factor α-and hyperglycaemiainduced increases in intercellular adhesion molecule-1, vascular cell adhesion molecule-1, plasminogen activator inhibitor type 1 and NFκB expression. Acute dapagliflozin administration dose-dependently induced endothelium-independent vasorelaxation. Chronic dapagliflozin treatment improved endothelial function and significantly reduced in vivo vascular adhesion molecule and phospho-IκB expression together with macrophage vessel wall infiltration. Conclusion: These observations identify a potential role for dapagliflozin in the attenuation of atherogenesis and identify anti-inflammatory molecular mechanisms associated with these effects.

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