Eugenosedin-A ameliorates hyperlipidemia-induced vascular endothelial dysfunction via inhibition of α1-adrenoceptor/5-HT activity and NADPH oxidase expression

Eugenosedin-A (Eu-A) effects on vascular endothelial dysfunction and oxidative stress in a hyperlipidemic rat model were investigated. Rats were randomly divided into four groups: two control groups and two treatment groups. The control rats received a regular diet or high fat diet (HFD); the treatment rats fed received an HFD with 5 mg/kg Eu-A or atorvastatin for 10 weeks. No changes in serotonin levels were observed in the four groups; norepinephrine levels were enhanced in the HFD group which was attenuated by Eu-A and atorvastatin. In the HFD group, the vascular reactivity was increased by vasoconstrictors (5-nonyloxytryptamine, 5-HT, and phenylephrine) and decreased by an endothelium-dependent vasorelaxant, carbachol. Protein levels of α1-adrenergic receptors (not 5-HT1B/2A), reactive oxygen species (ROS) p47(phox), p67(phox), and gp91(phox), and oxidative damage markers 3-nitrotyrosine (3-NT) and 4-hydroxy-2-nonenal (4-HNE) were increased, but endothelial nitric oxide synthase (eNOS), P-eNOS and vasodilator-stimulated phosphoprotein phosphorylation (P-VASP) were decreased. Catalase and superoxide dismutase (SOD-1 and SOD-2) proteins were increased, but glutathione peroxidase (GPx) was decreased in the aorta. Eu-A and atorvastatin reduced vasoconstrictor-induced aortic contractions that might be related to 5-HT1B/2A and α1-adrenergic receptors inhibitory activities. Eu-A and atorvastatin improved eNOS/P-eNOS, P-VASP, GPx, and malondialdehyde (MDA) levels, and decreased ROS and oxidative damage markers. Taken together, we suggest that Eu-A can ameliorate hyperlipidemia-induced vascular endothelial dysfunction and oxidative dysregulation.

Eugenosedin-A prevents high-fat diet increased adhesion molecules through inhibition of MAPK- and p65-mediated NF-κB pathway in rat model

Objectives

Previous studies have shown eugenosedin-A, a 5-HT1B/2A and α1/α2/β1-adrenergic blocker, is able to decrease cholesterol levels, hyperglycaemia and inflammation in hyperlipidaemic mice induced by high-fat diet (HFD). The aim of this study is to examine the effects of eugenosedin-A on the inhibition of adhesion molecules of platelets, the aorta and acyl-coenzymeA:cholesterol acyltransferase-1 (ACAT-1) of macrophages in a hyperlipidaemic rat model.

Methods

Six-week-old Sprague–Dawley rats were randomly divided into two control and treatment groups. The control rats received either a regular diet or HFD and the treatment groups were fed HFD with either 5 mg/kg eugenosedin-A or atorvastatin for a 10-week period.

Key findings

Compared with the two control groups, the HFD group had lower levels of high-density lipoprotein, higher concentrations of triglycerides, total cholesterol, low-density lipoprotein and insulin. The expression of adhesion molecules in platelets, aorta and monocyte-macrophage were enhanced by HFD. HFD also increased upstream proteins and their phosphorylated form in the aorta. In treatment groups, eugenosedin-A and atorvastatin improved HFD-induced hyperlipidaemia and levels of insulin. Eugenosedin-A reduced the upregulation of P-selectin, ICAM-1, ICAM-2, ICAM-3, VCAM, PECAM in platelets and inhibited E-selectin, ICAM-1, ICAM-2, ICAM-3, VCAM and PECAM protein levels in the aorta. Eugenosedin-A reduced the ACAT-1 protein expression of monocyte-macrophages. The expression of PKCα, MAPKs, IKKα and p65 and their phosphorylated form were reduced in treatment groups.

Conclusions

Taken together, hyperlipidaemia enhances the expression of adhesion molecules and ACAT-1 protein, and eugenosedin-A ameliorates those increases. Through inhibition of MAPK- and p-65-mediated NF-κB pathway, eugenosedin-A decreases the quantity of adhesion molecules.