Nitric oxide-mediated endothlium-dependent vasodilation is impaired with borderline high-LDL cholesterol

The Impacts of Animal-Based Diets in Cardiovascular Disease Development: A Cellular and Physiological Overview

Cardiovascular disease (CVD) is the leading cause of death in the United States, and diet plays an instrumental role in CVD development. Plant-based diets have been strongly tied to a reduction in CVD incidence. In contrast, animal food consumption may increase CVD risk. While increased serum low-density lipoprotein (LDL) cholesterol concentrations are an established risk factor which may partially explain the positive association with animal foods and CVD, numerous other biochemical factors are also at play. Thus, the aim of this review is to summarize the major cellular and molecular effects of animal food consumption in relation to CVD development. Animal-food-centered diets may (1) increase cardiovascular toll-like receptor (TLR) signaling, due to increased serum endotoxins and oxidized LDL cholesterol, (2) increase cardiovascular lipotoxicity, (3) increase renin-angiotensin system components and subsequent angiotensin II type-1 receptor (AT1R) signaling and (4) increase serum trimethylamine-N-oxide concentrations. These nutritionally mediated factors independently increase cardiovascular oxidative stress and inflammation and are all independently tied to CVD development. Public policy efforts should continue to advocate for the consumption of a mostly plant-based diet, with the minimization of animal-based foods.

Identification of securinine as vascular protective agent targeting atherosclerosis in vascular endothelial cells, smooth muscle cells, and apolipoprotein E deficient mice

BACKGROUND

Atherosclerosis is a chronic vascular disease and characterized by accumulation within the intima of inflammatory cells, smooth muscle cells, lipid, and connective tissue.

PURPOSE

The purpose of the present study was to identify natural agents that commonly reverse advanced atherosclerotic plaque to early atherosclerotic plaque.

METHODS

Differentially expressed genes (DEGs) were analyzed in silico. The differentially expressed genes from 9 intimal thickening and 8 fibrous cap atheroma tissue which were collected from GEO data were assessed by the connectivity map. Natural candidate securinine, a main compound from Securinega suffruticosa, was selected and administrated 1, 5 mg/kg/day in apolipoprotein-E-deficient (ApoE KO) mice for 18 weeks.

RESULTS

Securinine significantly showed lowered blood pressure and improvement of metabolic parameters with hyperlipidemia. The impairment in vasorelaxation was remarkably decreased by treatment with securinine. H&E staining revealed that treatment with securinine reduced atherosclerotic lesions. Securinine suppressed the expression of adhesion molecules and matrix metalloproteinase-2/-9 in both ApoE KO and vascular endothelial cells (HUVEC). In HUVEC pretreatment with securinine significantly inhibited ROS generation and NF-κB activation. Growth curve assays using the real-time cell analyzer showed that securinine significantly decreased TNF-α-induced aortic smooth muscle cell proliferation and migration in a dose-dependent manner.

CONCLUSION

Securinine may be a potential natural candidate for the treatment of atherosclerosis because it attenuates vascular inflammation and dysfunction as well as vascular lesion.

Arginase inhibition by (-)-Epicatechin reverses endothelial cell aging

Endothelial dysfunction (EnD) occurs with aging and endothelial nitric oxide (NO) production by NO synthase (NOS) can be impaired. Low NO levels have been linked to increased arginase (Ar) activity as Ar competes with NOS for L-arginine. The inhibition of Ar activity can reverse EnD and (-)-epicatechin (Epi) inhibits myocardial Ar activity. In this study, through in silico modeling we demonstrate that Epi interacts with Ar similarly to its inhibitor Norvaline (Norv). Using in vitro and in vivo models of aging, we examined Epi and Norv-inhibition of Ar activity and its endothelium-protective effects. Bovine coronary artery endothelial cells (BCAEC) were treated with Norv (10 μM), Epi (1 μM) or the combination (Epi + Norv) for 48 h. Ar activity increased in aged BCAEC, with decreased NO generation. Treatment decreased Ar activity to levels seen in young cells. Epi and Epi + Norv decreased nitrosylated Ar levels by ~25% in aged cells with lower oxidative stress (~25%) (dihydroethidium) levels. In aged cells, Epi and Epi + Norv restored the eNOS monomer/dimer ratio, protein expression levels and NO production to those of young cells. Furthermore, using 18 month old rats 15 days of treatment with either Epi (1 mg/kg), Norv (10 mg/kg) or combo, decreased hypertension and improved aorta vasorelaxation to acetylcholine, blood NO levels and tetra/dihydribiopterin ratios in cultured rat aortic endothelial cells. In conclusion, results provide evidence that inhibiting Ar with Epi reverses aged-related loss of eNOS function and improves vascular function through the modulation of Ar and eNOS protein levels and activity.

Angiotensin II, Hypercholesterolemia, and Vascular Smooth Muscle Cells: A Perfect Trio for Vascular Pathology

Cardiovascular disease is the leading cause of morbidity and mortality in the Western and developing world, and the incidence of cardiovascular disease is increasing with the longer lifespan afforded by our modern lifestyle. Vascular diseases including coronary heart disease, high blood pressure, and stroke comprise the majority of cardiovascular diseases, and therefore represent a significant medical and socioeconomic burden on our society. It may not be surprising that these conditions overlap and potentiate each other when we consider the many cellular and molecular similarities between them. These intersecting points are manifested in clinical studies in which lipid lowering therapies reduce blood pressure, and anti-hypertensive medications reduce atherosclerotic plaque. At the molecular level, the vascular smooth muscle cell (VSMC) is the target, integrator, and effector cell of both atherogenic and the major effector protein of the hypertensive signal Angiotensin II (Ang II). Together, these signals can potentiate each other and prime the artery and exacerbate hypertension and atherosclerosis. Therefore, VSMCs are the fulcrum in progression of these diseases and, therefore, understanding the effects of atherogenic stimuli and Ang II on the VSMC is key to understanding and treating atherosclerosis and hypertension. In this review, we will examine studies in which hypertension and atherosclerosis intersect on the VSMC, and illustrate common pathways between these two diseases and vascular aging.

Beneficial effects of acute trans-resveratrol supplementation in treated hypertensive patients with endothelial dysfunction

Endothelial dysfunction is a surrogate marker of cardiovascular risk. Resveratrol is known to improve endothelial function in animals, however, clinical trials are limited. We hypothesized that the acute trans-resveratrol supplementation improves endothelial function in treated hypertensive patients with endothelial dysfunction. Twenty-four hypertensive patients between 45 and 65 years-old with baseline endothelial dysfunction were enrolled in a randomized, cross-over, double-blind, placebo-controlled trial. Individuals received either a single dose of trans-resveratrol (300 mg) or placebo and were crossed-over after a one-week washout period. Blood pressure (BP) measurements, aortic systolic blood pressure (SBP) and brachial flow-mediated dilation (FMD) were performed before and 1.5 hours after the intervention. FMD was significantly increased in women (4.2 ± 0.5 vs 7.1 ± 1.3%, p = 0.026) but not in men (4.4 ± 0.9 vs 4.9 ± 0.8%, p = 0.588) in the trans-resveratrol group. There was no statistical difference between baseline and final values of brachial BP and also no changes in aortic SBP. Patients with higher low-density lipoprotein (LDL) cholesterol had better FMD response to trans-resveratrol than patients with lower LDL cholesterol (7.4 ± 1.2 vs 4.3 ± 1.0%, p = 0.004). Our study demonstrated that the acute supplementation of trans-resveratrol promoted an improvement in endothelial function, especially in women and those with higher LDL-cholesterol, despite no changes in BP. List of Abbreviation: Aix: augmentation index; AP: augmentation pressure; BP: blood pressure; BMI: body Mass Index; CVD: cardiovascular disease; FMD: flow-mediated dilation; FRS: Framingham Risk Score; HDL: high-density lipoprotein; LDL: low-density lipoprotein; NO: nitric oxide; SPSS: Statistical Package for Social Sciences; ROS: reactive oxygen species; SBP: systolic blood pressure; TG: triglycerides.

Arginase inhibition improves endothelial function in patients with familial hypercholesterolaemia irrespective of their cholesterol levels

BACKGROUND

Elevated LDL cholesterol is an important risk factor for atherosclerosis. Endothelial dysfunction, an early event in the development of atherosclerosis, is characterized by a reduction in nitric oxide (NO) bioavailability. Arginase has emerged as a key regulator of endothelial function through competition with NO synthase for the common substrate l-arginine. Arginase in endothelial cells is activated by oxidized LDL. The study aim was to investigate the importance of arginase for endothelial dysfunction in patients with familial hypercholesterolaemia (FH).

METHODS AND RESULTS

Endothelial function was evaluated in 12 patients with heterozygous FH and 12 age-matched healthy normocholesterolaemic subjects using forearm venous occlusion plethysmography. The evaluations in FH patients occurred when they were on lipid-lowering therapy and 4 weeks after withdrawal of treatment. Endothelium-dependent vasodilatation (EDV) was assessed by intrabrachial artery infusion of serotonin, and endothelium-independent dilatation was assessed by infusion of nitroprusside before and after 120 min administration of the arginase inhibitor N (ω) -hydroxy-nor-l-arginine (nor-NOHA; 0.1 mg min(-1)). In FH patients LDL cholesterol increased from 4.3 ± 0.9 mmol L(-1) at baseline to 7.6 ± 1.9 mmol L(-1) at follow-up (P < 0.001). Arginase inhibition enhanced EDV in FH patients by a similar degree independent of lipid-lowering therapy. The improvement in EDV by arginase inhibition was significantly greater in FH patients than in the control group.

CONCLUSION

Arginase inhibition results in greater improvement in endothelial function in patients with FH compared to healthy controls irrespective of their cholesterol levels. Arginase may be a promising therapeutic target for improving endothelial function in patients with hypercholesterolaemia.