Protection of endothelial function: targets for nutritional and pharmacological interventions

NMR-Based Metabolomic Analysis on the Protective Effects of Apolipoprotein A-I Mimetic Peptide against Contrast Media-Induced Endothelial Dysfunction

Endothelial dysfunction plays key roles in the pathological process of contrast media (CM)-induced acute kidney injury (CI-AKI) in patients undergoing vascular angiography or intervention treatment. Previously, we have demonstrated that an apolipoprotein A-I (apoA-I) mimetic peptide, D-4F, inhibits oxidative stress and improves endothelial dysfunction caused by CM through the AMPK/PKC pathway. However, it is unclear whether CM induce metabolic impairments in endothelial cells and whether D-4F ameliorates these metabolic impairments. In this work, we evaluated vitalities of human umbilical vein endothelial cells (HUVECs) treated with iodixanol and D-4F and performed nuclear magnetic resonance (NMR)-based metabolomic analysis to assess iodixanol-induced metabolic impairments in HUVECs, and to address the metabolic mechanisms underlying the protective effects of D-4F for ameliorating these metabolic impairments. Our results showed that iodixanol treatment distinctly impaired the vitality of HUVECs, and greatly disordered the metabolic pathways related to energy production and oxidative stress. Iodixanol activated glucose metabolism and the TCA cycle but inhibited choline metabolism and glutathione metabolism. Significantly, D-4F pretreatment could improve the iodixanol-impaired vitality of HUVECs and ameliorate the iodixanol-induced impairments in several metabolic pathways including glycolysis, TCA cycle and choline metabolism in HUVECs. Moreover, D-4F upregulated the glutathione level and hence enhanced antioxidative capacity and increased the levels of tyrosine and nicotinamide adenine dinucleotide in HUVECs. These results provided the mechanistic understanding of CM-induced endothelial impairments and the protective effects of D-4F for improving endothelial cell dysfunction. This work is beneficial to further exploring D-4F as a potential pharmacological agent for preventing CM-induced endothelial impairment and acute kidney injury.

Acute Effects of Cocoa Flavanols on Blood Pressure and Peripheral Vascular Reactivity in Type 2 Diabetes Mellitus and Essential Hypertension: A Protocol for an Acute, Randomized, Double-Blinded, Placebo-Controlled Cross-Over Trial

Introduction: Patients with type 2 diabetes mellitus are at high risk to develop vascular complications resulting in high morbidity and mortality. Cocoa flavanols are promising nutraceuticals with possible beneficial vascular effects in humans. However, limited research is currently available on the vascular effects in a diabetic population with inconsistent results. Possible reasons for this inconsistency might be heterogeneity in the given intervention (dose per time and day, single dose vs. split-dose, placebo formula) and the studied population (blood pressure at baseline, duration of diabetes, use of vasoactive antihypertensive and antidiabetic drugs, sex). Therefore, we aimed to develop a randomized, double-blinded, placebo-controlled cross-over trial to investigate whether cocoa flavanols have an acute impact on blood pressure and vascular reactivity in patients with type 2 diabetes with and without arterial hypertension.

Methods and Analysis: We will include participants in four groups: (i) patients with type 2 diabetes without arterial hypertension, (ii) patients with type 2 diabetes with arterial hypertension and 1 antihypertensive drug, (iii) non-diabetic participants with essential hypertension and 1 antihypertensive drug, and (iv) healthy controls. All participants will complete the same protocol on both testing days, consuming high-flavanol cocoa extract (790 mg flavanols) or placebo. Macrovascular endothelial function (flow-mediated dilation) and blood pressure will be measured before and after capsule ingestion. Forearm muscle vasoreactivity (near-infrared spectroscopy) and brachial artery blood flow (echo-doppler) will be assessed in response to a dynamic handgrip exercise test after capsule ingestion. Data will be analyzed with a random intercept model in mixed models.

Clinical Trial Registration:www.Clinicaltrials.gov, identifier: NCT03722199.

A protective effect of curcumin on cardiovascular oxidative stress indicators in systemic inflammation induced by lipopolysaccharide in rats

Objective

Inflammation has been considered as an important factor in cardiovascular diseases (CVD). Curcumin has been well known for its anti-inflammatory effects. In current research, protective effect of curcumin on cardiovascular oxidative stress indicators in systemic inflammation induced by lipopolysaccharide (LPS) was investigated in rats.

Material and methods

The animals were divided into five groups and received the treatments during two weeks [1]: Control in which vehicle was administered instead of curcumin and saline was injected instead of LPS [2], LPS group in which vehicle of curcumin plus LPS (1 mg/kg) was administered [3-5], curcumin groups in them three doses of curcumin (5, 10 and 15 mg/kg) before LPS were administered.

Results

Administration of LPS was followed by an inflammation status presented by an increased level of white blood cells (WBC) (p < 0.001). An oxidative stress status was also occurred after LPS injection which was presented by an increased level of malondialdehyde (MDA) while, a decrease in thiols, superoxide dismutase (SOD) and catalase(CAT) in all heart, aorta and serum (p < 0.001). The results also showed that curcumin decreased WBC (doses: 10 and 15 mg/kg) (p < 0.001) accompanying with a decrease in MDA (P < 0.01 and P < 0.001). Curcumin also improved the thiols and the activities of SOD and catalase (P < 0.05, P < 0.01 and P < 0.001).

Conclusion

Based on our findings, curcumin can ameliorates oxidative stress and inflammation induced by LPS in rats to protect the cardiovascular system.

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The aim of the present study was to investigate the cardiovascular protective effects of curcumin in lipopolysaccharide (LPS) challenged rats

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Lipopolysaccharide (LPS) induced inflammation model in rats

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LPS injection was followed by inflammation and induced oxidative stress status in the serum, aorta and heart.

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Administration of curcumin attenuated oxidative stress and inflammation in the serum, aorta and heart tissues induced by LPS.

Endothelial function in cardiovascular medicine: a consensus paper of the European Society of Cardiology Working Groups on Atherosclerosis and Vascular Biology, Aorta and Peripheral Vascular Diseases, Coronary Pathophysiology and Microcirculation, and Thrombosis

Endothelial cells (ECs) are sentinels of cardiovascular health. Their function is reduced by the presence of cardiovascular risk factors, and is regained once pathological stimuli are removed. In this European Society for Cardiology Position Paper, we describe endothelial dysfunction as a spectrum of phenotypic states and advocate further studies to determine the role of EC subtypes in cardiovascular disease. We conclude that there is no single ideal method for measurement of endothelial function. Techniques to measure coronary epicardial and micro-vascular function are well established but they are invasive, time-consuming, and expensive. Flow-mediated dilatation (FMD) of the brachial arteries provides a non-invasive alternative but is technically challenging and requires extensive training and standardization. We, therefore, propose that a consensus methodology for FMD is universally adopted to minimize technical variation between studies, and that reference FMD values are established for different populations of healthy individuals and patient groups. Newer techniques to measure endothelial function that are relatively easy to perform, such as finger plethysmography and the retinal flicker test, have the potential for increased clinical use provided a consensus is achieved on the measurement protocol used. We recommend further clinical studies to establish reference values for these techniques and to assess their ability to improve cardiovascular risk stratification. We advocate future studies to determine whether integration of endothelial function measurements with patient-specific epigenetic data and other biomarkers can enhance the stratification of patients for differential diagnosis, disease progression, and responses to therapy.

Modeling early stage atherosclerosis in a primary human vascular microphysiological system

Novel atherosclerosis models are needed to guide clinical therapy. Here, we report an in vitro model of early atherosclerosis by fabricating and perfusing multi-layer arteriole-scale human tissue-engineered blood vessels (TEBVs) by plastic compression. TEBVs maintain mechanical strength, vasoactivity, and nitric oxide (NO) production for at least 4 weeks. Perfusion of TEBVs at a physiological shear stress with enzyme-modified low-density-lipoprotein (eLDL) with or without TNFα promotes monocyte accumulation, reduces vasoactivity, alters NO production, which leads to endothelial cell activation, monocyte accumulation, foam cell formation and expression of pro-inflammatory cytokines. Removing eLDL leads to recovery of vasoactivity, but not loss of foam cells or recovery of permeability, while pretreatment with lovastatin or the P2Y11 inhibitor NF157 reduces monocyte accumulation and blocks foam cell formation. Perfusion with blood leads to increased monocyte adhesion. This atherosclerosis model can identify the role of drugs on specific vascular functions that cannot be assessed in vivo.

Long term treatment with quercetin in contrast to the sulfate and glucuronide conjugates affects HIF1α stability and Nrf2 signaling in endothelial cells and leads to changes in glucose metabolism

Endothelial functionality profoundly contributes to cardiovascular health. The effects of flavonoids shown to improve endothelial performance include regulating blood pressure by modulating endothelial nitric oxide synthase and NADPH oxidases, but their impact on glucose uptake and metabolism has not been explored. We treated human umbilical vein endothelial cells (HUVEC) with the flavonoid quercetin and its circulating metabolites acutely and chronically, then assessed glucose uptake, glucose metabolism, gene transcription and protein expression. Acute treatment had no effect on glucose uptake, ruling out any direct interaction with sugar transporters. Long term treatment with quercetin, but not quercetin 3-O-glucuronide or 3'-O-sulfate, significantly increased glucose uptake. Heme oxygenase-1 (HO-1) was induced by quercetin but not its conjugates, but was not implicated in the glucose uptake stimulation since hemin, a classical inducer of HO-1, did not affect glucose metabolism. Quercetin increased stability of the transcription factor hypoxia induced factor 1α (HIF1α), a powerful stimulant of glucose metabolism, which was also paralleled by treatment with a prolyl-4-hydroxylase inhibitor dimethyloxalylglycine (DMOG). 6-Phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3), which regulates the rate of glycolysis, was upregulated by both quercetin and DMOG. Pyruvate dehydrogenase kinase (PDK) isoforms regulate pyruvate dehydrogenase; PDK2 and PDK4 were down-regulated by both effectors, but only DMOG also upregulated PDK1 and PDK3. Quercetin, but not DMOG, increased glucose-6-phosphate dehydrogenase. Chronic quercetin treatment also stimulated glucose transport across the HUVEC monolyer in a 3D culture model. Gene expression of several flavonoid transporters was repressed by quercetin, but this was either abolished (Organic anion transporter polypeptide 4C1) or reversed (Multidrug resistance gene 1) by both conjugates. We conclude that quercetin and its circulating metabolites differentially modulate glucose uptake/metabolism in endothelial cells, through effects on HIF1α and transcriptional regulation of energy metabolism.

Endothelial dysfunction in cardiovascular disease and Flammer syndrome-similarities and differences

The endothelium has increasingly been recognized as a smart barrier and a key regulator of blood flow in micro- and macrovascular beds. Endothelial dysfunction marks a stage of atherosclerosis and is an important prognostic marker for cardiovascular disease. Yet, some people who tend to be slim and physically active and with rather low blood pressure show a propensity to respond to certain stimuli such as emotional stress with endothelial-mediated vascular dysregulation (Flammer syndrome). This leads to characteristic vascular symptoms such as cold hands but also a risk for vascular-mediated diseases such as normal-tension glaucoma. It is the aim of this review to delineate the differences between Flammer syndrome and its "counterpart" endothelial dysfunction in the context of cardiovascular diseases.

High glucose induced endothelial to mesenchymal transition in human umbilical vein endothelial cell

BACKGROUND

Studies have shown that endothelial-to-mesenchymal transition (EndMT) could contribute to the progression of diabetic nephropathy, diabetic renal fibrosis, and cardiac fibrosis. The aim of this study was to investigate the influence of high glucose and related mechanism of MAPK inhibitor or specific antioxidant on the EndMT.

METHODS

In vitro human umbilical vein endothelial cells (HUVEC) were cultured with 11mM, 30mM, 60mM and 120mM glucose for 0, 24, 48, 72 and 168h. Endothelial cell morphology was observed with microscope, and RT-PCR was used to detect mRNA expression of endothelial markers VE-cadherin and CD31, mesenchymal markers α-SMA and collagen I, and transforming growth factor TGF-β1. Immunofluorescence staining was performed to detect the expression of CD31 and α-SMA. The concentration of TGF-β1 in the supernatant was detected by ELISA. ERK1/2 phosphorylation level was detected by Western blot analysis.

RESULTS

High glucose induced EndMT and increased the TGF-β1 level in HUVEC cells. Cells in high glucose for 7 days showed a significant decrease in mRNA expression of CD31 and VE-cadherin, and a significant increase in that of α-SMA and collagen I, while lost CD31 staining and acquired α-SMA staining. ERK signaling pathway blocker PD98059 significantly attenuated the high glucose-induced increase in the ERK1/2 phosphorylation level. PD98059 and NAC both inhibited high glucose-induced TGF-β1 expression and attenuated EndMT marker protein synthesis.

CONCLUSION

High glucose could induce HUVEC cells to undergo EndMT. NAC and ERK signaling pathway may play important role in the regulation of the TGF-β1 biosynthesis during high glucose-induced EndMT.

Cilostazol Induces PGI2 Production via Activation of the Downstream Epac-1/Rap1 Signaling Cascade to Increase Intracellular Calcium by PLCε and to Activate p44/42 MAPK in Human Aortic Endothelial Cells

Background

Cilostazol, a selective phosphodiesterase 3 (PDE3) inhibitor, is known as an anti-platelet drug and acts directly on platelets. Cilostazol has been shown to exhibit vascular protection in ischemic diseases. Although vascular endothelium-derived prostaglandin I₂ (PGI₂) plays an important role in vascular protection, it is unknown whether cilostazol directly stimulates PGI₂ synthesis in endothelial cells. Here, we elucidate the mechanism of cilostazol-induced PGI₂ stimulation in endothelial cells.

Methods and Results

Human aortic endothelial cells (HAECs) were stimulated with cilostazol and PGI₂ accumulation in the culture media was measured. Cilostazol increased PGI₂ synthesis via the arachidonic acid pathway. Cilostazol-induced intracellular calcium also promoted PGI₂ synthesis via the inositol 1,4,5-trisphosphate receptor. Using RNAi, silencing of PDE3B abolished the induction effect of cilostazol on PGI₂ synthesis and intracellular cAMP accumulation. Inhibition of the exchange protein, which was directly activated by cyclic AMP 1 (Epac-1) and its downstream signal the Ras-like small GTPase (Rap-1), abolished cilostazol-induced PGI₂ synthesis, but this did not take place via protein kinase A (PKA). Inhibition of downstream signaling, such as mitogen-activated protein kinase (MAPK), phosphoinositide 3-kinase (PI3K) γ, and phospholipase C (PLC) ε, suppressed cilostazol-induced PGI₂ synthesis.

Conclusions

The PDE3/Epac-1/Rap-1 signaling pathway plays an important role in cilostazol-induced PGI₂ synthesis. Namely, stimulation of HAECs with cilostazol induces intracellular calcium elevation via the Rap-1/PLCε/IP3 pathway, along with MAPK activation via direct activation by Epac-1/Rap-1 and indirect activation by Epac-1/Rap-1/PI3Kγ, resulting in synergistically induced PGI₂ synthesis.

Egg ovotransferrin-derived ACE inhibitory peptide IRW increases ACE2 but decreases proinflammatory genes expression in mesenteric artery of spontaneously hypertensive rats

Scope

Egg ovotransferrin‐derived angiotensin converting enzyme (ACE) inhibitory peptide IRW was previously shown to reduce blood pressure in spontaneously hypertensive rats through reduced vascular inflammation and increased nitric oxide‐mediated vasorelaxation. The main objective of the present study was to investigate the molecular mechanism of this peptide through transcriptome analysis by RNAseq technique.

Methods and results

Total RNA was extracted from kidney and mesenteric arteries; the RNAseq libraries (from untreated and IRW‐treated groups) were constructed and subjected to sequence using HiSeq 2000 system (Illumina) system. A total of 12 764 and 13 352 genes were detected in kidney and mesenteric arteries, respectively. The differentially expressed (DE) genes between untreated and IRW‐treated groups were identified and the functional analysis through ingenuity pathway analysis revealed a greater role of DE genes identified from mesenteric arteries than that of kidney in modulating various cardiovascular functions. Subsequent qPCR analysis further confirmed that IRW significantly increased the expression of ACE‐2, ABCB‐1, IRF‐8, and CDH‐1 while significantly decreased the expression ICAM‐1 and VCAM‐1 in mesenteric arteries.

Conclusion

Our research showed for the first time that ACE inhibitory peptide IRW could contribute to its antihypertensive activity through increased ACE2 and decreased proinflammatory genes expression.

Molecular targets of antihypertensive peptides: understanding the mechanisms of action based on the pathophysiology of hypertension

There is growing interest in using functional foods or nutraceuticals for the prevention and treatment of hypertension or high blood pressure. Although numerous preventive and therapeutic pharmacological interventions are available on the market, unfortunately, many patients still suffer from poorly controlled hypertension. Furthermore, most pharmacological drugs, such as inhibitors of angiotensin-I converting enzyme (ACE), are often associated with significant adverse effects. Many bioactive food compounds have been characterized over the past decades that may contribute to the management of hypertension; for example, bioactive peptides derived from various food proteins with antihypertensive properties have gained a great deal of attention. Some of these peptides have exhibited potent in vivo antihypertensive activity in both animal models and human clinical trials. This review provides an overview about the complex pathophysiology of hypertension and demonstrates the potential roles of food derived bioactive peptides as viable interventions targeting specific pathways involved in this disease process. This review offers a comprehensive guide for understanding and utilizing the molecular mechanisms of antihypertensive actions of food protein derived peptides.

Physical activity on endothelial and erectile dysfunction: a literature review

Physical inactivity, diabetes, hypertension, dyslipidemia, smoking and obesity were associated with imbalance in oxidative stress, leading to endothelial dysfunction. Such dysfunction is present in both cardiovascular disease (CVD) and erectile dysfunction (ED). ED is the persistent inability to achieve or sustain an erection sufficient for satisfactory sexual performance and is one of the first manifestations of endothelial damage in men with CVD risk factors. The purpose of this article is to review the results of studies involving physical activity, CVD, endothelial dysfunction and ED in order to verify its applicability for improving the health and quality of life of men with such disorders. There is consistent evidence that endothelial damage is intimately linked to ED, and this manifestation seems to be associated with the appearance CVDs. On the other hand, physical activity has been pointed out as an important clinical strategy in the prevention and treatment of CVDs and ED mainly associated with improvement of endothelial function. However, further experimental and clinical prospective investigations are needed to test the role of physical exercises in the modulation of endothelial function and their implications on erectile function and the appearance of CVDs.

Inhibitory effect of Malvidin on TNF-α-induced inflammatory response in endothelial cells

Vascular inflammatory responses are key mediators of endothelial dysfunction that leads to various pathologies in many diseases including atherosclerosis and cancer. The purpose of the study was to investigate the effects and molecular mechanisms of Malvidin, a natural pigment with strong antioxidant activity, on regulating inflammatory response in endothelial cells. Our results showed that tumor necrosis factor-alpha (TNF-α) significantly increased the protein or mRNA levels of monocyte chemotactic protein-1 (MCP-1), intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1), whereas pretreatment with Malvidin inhibited TNF-α-induced increases of MCP-1, ICAM-1, and VCAM-1 production in a concentration-dependent manner. In addition, Malvidin could inhibit degradation of IκBα and the nuclear translocation of p65, which suggesting the anti-inflammation mechanism of Malvidin by the nuclear factor kappa B (NF-κB) pathway. These results indicate the potential role of Malvidin in preventing chronic inflammation in many diseases.

Long-term dietary intake of selenium, calcium, and dairy products is associated with improved capillary recruitment in healthy young men

PURPOSE

To identify associations between long-term (1 year) food intake and skin nutritive microvascular function in healthy subjects.

METHODS

This was a cross-sectional study. A validated 88-item food-frequency questionnaire was administered to 39 healthy men aged 23.4 ± 0.5 years and body mass index 23.3 ± 2.3 kg/m², who reported food intake during the last year and underwent videocapillaroscopy exams. The main outcome was the increase in functional capillary recruitment, that is, peak capillary density after post-occlusive reactive hyperemia subtracted from basal capillary density (caps/mm²). Associations between reported food intake and functional capillary recruitment were investigated.

RESULTS

Daily average estimates of intake were: total energy (3,745 ± 1,365 kcal), carbohydrates (60.1 ± 5.9 %), lipids (22.1 ± 4.4 %), proteins (17.8 ± 4.1 %), fibers (33.9 ± 18.5 g), and cholesterol (492.8 ± 209.6 mg). Positive significant correlations with capillary recruitment were found for selenium (as μg/day/1,000 kcal; rho = 0.3412, p = 0.038,) calcium (as mg/day/1,000 kcal; rho = 0.3390, p = 0.043), and percentage of total energy from dairy products (rho = 0.3660, p = 0.023).

CONCLUSIONS

Long-term intakes of selenium, calcium, and dairy products were positively associated with capillary recruitment in skin nutritive microcirculation in healthy young men. The role of such dietary components is discussed and possible mechanisms for their effects should be further investigated. This evidence adds one more possible functional property of these nutrients and food items.

Interactome: Smart hematophagous triatomine salivary gland molecules counteract human hemostasis during meal acquisition

Human populations are constantly plagued by hematophagous insects' bites, in particular the triatomine insects that are vectors of the Trypanosoma cruzi agent in Chagas disease. The pharmacologically-active molecules present in the salivary glands of hematophagous insects are injected into the human skin to initiate acquisition of blood meals. Sets of vasodilators, anti-platelet aggregators, anti-coagulants, immunogenic polypeptides, anesthetics, odorants, antibiotics, and detoxifying molecules have been disclosed with the aid of proteomics and recombinant cDNA techniques. These molecules can provide insights about the insect-pathogen-host interactions essential for understanding the physiopathology of the insect bite. The data and information presented in this review aim for the development of new drugs to prevent insect bites and the insect-transmitted endemic of Chagas disease.

PEDF in diabetic retinopathy: a protective effect of oxidative stress

Diabetic retinopathy (DR) is a major cause of blindness in working age adults, and oxidative stress plays a vital role in the pathogenesis of DR. Pigment-epithelium-derived factor (PEDF), a multifunctional protein, has shown to inhibit the development of DR by accumulating evidence. This paper highlights the current understanding of probable mechanism about how PEDF blocks the deterioration of DR through its antioxidative properties and application prospects of PEDF as a novel therapeutic target in DR. Gene therapy of PEDF is becoming more and more acceptable and will widely be applied to the actual treatment in the near future.

Paracrine effects of mesenchymal stem cells enhance vascular regeneration in ischemic murine skin

New theories on the regeneration of ischemic vasculature have emerged indicating a pivotal role of adult stem cells. The aim of this study was to investigate homing and hemodynamic effects of circulating bone marrow-derived mesenchymal stem cells (MSCs) in a critically ischemic murine skin flap model. Bone marrow-derived mesenchymal stem cells (Lin(-)CD105(+)) were harvested from GFP(+)-donor mice and transferred to wildtype C57BL/6 mice. Animals receiving GFP(+)-fibroblasts served as a control group. Laser scanning confocal microscopy and intravital fluorescence microscopy were used for morphological analysis, monitoring and quantitative assessment of the stem cell homing and microhemodynamics over two weeks. Immunohistochemical staining was performed for GFP, eNOS, iNOS, VEGF. Tissue viability was analyzed by TUNEL-assay. We were able to visualize perivascular homing of MSCs in vivo. After 4 days, MSCs aligned along the vascular wall without undergoing endothelial or smooth muscle cell differentiation during the observation period. The gradual increase in arterial vascular resistance observed in the control group was abolished after MSC administration (P<0.01). At capillary level, a strong angiogenic response was found from day 7 onwards. Functional capillary density was raised in the MSC group to 197% compared to 132% in the control group (P<0.01). Paracrine expression of VEGF and iNOS, but not eNOS could be shown in the MSC group but not in the controls. In conclusion, we demonstrated that circulating bone marrow-derived MSCs home to perivascular sites in critically ischemic tissue, exhibits paracrine function and augment microhemodynamics. These effects were mediated through arteriogenesis and angiogenesis, which contributed to vascular regeneration.

Food selection based on high total antioxidant capacity improves endothelial function in a low cardiovascular risk population

BACKGROUND AND AIMS

Oxidative stress has been advocated as a major cause for cardiovascular disease (CVD), and low plasma antioxidant concentrations are associated with endothelial dysfunction, the first step towards atherosclerosis. However, although the antioxidant content in fruits and vegetables may explain at least in part their protective effect against CVD, supplementation with antioxidant vitamins fails to improve endothelial function and reduce CVD risk. The aim of this study was to investigate the impact of a diet rich in antioxidants on endothelial function measured by flow-mediated dilatation (FMD) in volunteers at low cardiovascular risk.

METHODS AND RESULTS

In a crossover trial, 24 subjects (13 women, mean age 61 ± 3 years), received, in a randomised order, a 14-day high (HT) and a 14-day low (LT) antioxidant diets, with a 2-week wash-out (WO) in between. Both diets were comparable in daily portions of fruits and vegetables, and in alcohol, fibre and macronutrient intake, but differed in their total antioxidant capacity. Before and after each diet, anthropometrics, blood pressure, fasting plasma glucose, lipid profile, hepatic enzymes, circulating antioxidant concentrations, high sensitivity C-reactive protein (hs-CRP) and FMD were assessed. FMD increased significantly during the HT diet compared to the LT (p < 0.000). FMD values were 2.3% higher after HT compared with LT (p < 0.001) after adjustment for age, gender and diet order. α-tocopherol increased significantly (p < 0.05) and hs-CRP and of γ-glutamyltranspeptidase decreased significantly (p < 0.05 and p < 0.01, respectively) during the HT diet, compared with the LT diet.

CONCLUSIONS

A short-term HT diet improves endothelial function in volunteers at low cardiovascular risk, which may further reduce their risk of CVD.

Hypercholesterolemia and microvascular dysfunction: interventional strategies

Hypercholesterolemia is defined as excessively high plasma cholesterol levels, and is a strong risk factor for many negative cardiovascular events. Total cholesterol levels above 200 mg/dl have repeatedly been correlated as an independent risk factor for development of peripheral vascular (PVD) and coronary artery disease (CAD), and considerable attention has been directed toward evaluating mechanisms by which hypercholesterolemia may impact vascular outcomes; these include both results of direct cholesterol lowering therapies and alternative interventions for improving vascular function. With specific relevance to the microcirculation, it has been clearly demonstrated that evolution of hypercholesterolemia is associated with endothelial cell dysfunction, a near-complete abrogation in vascular nitric oxide bioavailability, elevated oxidant stress, and the creation of a strongly pro-inflammatory condition; symptoms which can culminate in profound impairments/alterations to vascular reactivity. Effective interventional treatments can be challenging as certain genetic risk factors simply cannot be ignored. However, some hypercholesterolemia treatment options that have become widely used, including pharmaceutical therapies which can decrease circulating cholesterol by preventing either its formation in the liver or its absorption in the intestine, also have pleiotropic effects with can directly improve peripheral vascular outcomes. While physical activity is known to decrease PVD/CAD risk factors, including obesity, psychological stress, impaired glycemic control, and hypertension, this will also increase circulating levels of high density lipoprotein and improving both cardiac and vascular function. This review will provide an overview of the mechanistic consequences of the predominant pharmaceutical interventions and chronic exercise to treat hypercholesterolemia through their impacts on chronic sub-acute inflammation, oxidative stress, and microvascular structure/function relationships.

Egg-derived peptide IRW inhibits TNF-α-induced inflammatory response and oxidative stress in endothelial cells

Oxidative stress and vascular inflammatory response are key mediators of endothelial dysfunction that leads to cardiovascular diseases. A novel peptide, IRW, was previously characterized from egg protein with angiotensin converting enzyme inhibitory activity. The purpose of the study was to investigate the effects and molecular mechanisms of IRW on regulating inflammatory response in endothelial cells. The results showed that tumor necrosis factor-α (TNF-α) significantly increased the protein levels of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and monocyte chemotactic protein-1 (MCP-1), whereas pretreatment with IRW inhibited TNF-α-induced increases of ICAM-1, VCAM-1, and MCP-1 production in a concentration-dependent manner. IRW also reduced the levels of superoxide ions in the presence and absence of TNF-α. These results indicate the potential role of IRW in preventing cardiovascular disease as a functional food ingredient or nutraceutical.

Caffeine's Vascular Mechanisms of Action

Caffeine is the most widely consumed stimulating substance in the world. It is found in coffee, tea, soft drinks, chocolate, and many medications. Caffeine is a xanthine with various effects and mechanisms of action in vascular tissue. In endothelial cells, it increases intracellular calcium stimulating the production of nitric oxide through the expression of the endothelial nitric oxide synthase enzyme. Nitric oxide is diffused to the vascular smooth muscle cell to produce vasodilation. In vascular smooth muscle cells its effect is predominantly a competitive inhibition of phosphodiesterase, producing an accumulation of cAMP and vasodilation. In addition, it blocks the adenosine receptors present in the vascular tissue to produce vasoconstriction. In this paper the main mechanisms of action of caffeine on the vascular tissue are described, in which it is shown that caffeine has some cardiovascular properties and effects which could be considered beneficial.

Vasoactive and antioxidant activities of plants used in Mexican traditional medicine for the treatment of cardiovascular diseases

This study demonstrated that the aqueous extracts of plants employed in Mexican traditional medicine for the treatment of cardiovascular diseases are able to modify the tone of arterial smooth muscle. Agastache mexicana (Kunth) Lint & Epling (Labiatae), Chenopodium murale L. (Chenopodiaceae), Chirantodendron pentadactylon Larreat (Sterculiaceae), Dracocephalum moldavica L. (Labiatae), Psittacanthus calyculatus G. Don (Loranthaceae), Prunus serotina ssp. capuli (Cav. ex Spreng) McVaugh (Rosaceae), and Sechium edule Sw. (Cucurbitaceae) contain secondary metabolites that promote vascular relaxation and display antioxidant activities. As expected, their antioxidant effects showed a significant correlation with the polyphenolics content. However, a lower correlation was found between the antioxidant activity and the maximum vasodilatory effect, suggesting that the vasodilatation elicited by the plant extracts could be only partly attributed to their antioxidant properties. The extract of P. calyculatus, which displayed a maximum vasorelaxant effect that was higher than that of acetylcholine, induced endothelium-dependent vasodilatation. Futhermore, the vasorelaxant response to the P. calyculatus extract was reduced after adding an inhibitor of soluble guanylate cyclase activity, providing evidence that the NO/cGMP pathway is involved. On the other hand, the extracts of Bocconia frutescens L. (Papaveraceae), Magnolia grandiflora L. (Magnoliaceae), and Solanum rostratum Dunal (Solanaceae) induced concentration-dependent contraction of rat aortic rings, suggesting that these plants have potential health benefits for the treatment of ailments such as venous insufficiency. The pharmacological activities of the extracts studied provide scientific support for their ethnomedical use.

Pharmacologic approaches for the management of symptoms and cardiovascular consequences of obstructive sleep apnea in adults

INTRODUCTION

Obstructive sleep apnea (OSA) is characterized by intermittent hypoxemia, arousals from sleep, and daytime sleepiness. Accumulating evidence indicates that hypoxemia and sleep disruption contribute to the development of cardiovascular abnormalities in OSA. OSA is effectively treated with continuous positive airway pressure (CPAP) therapy that splints open the airway during sleep. Studies have shown that CPAP therapy improves daytime sleepiness and attenuates cardiovascular abnormalities in patients with OSA. However, not all patients with OSA tolerate or adhere to CPAP therapy. Even patients who regularly use CPAP therapy may have a few hours each night exposed to the negative effects of untreated OSA. As a result, complementary pharmacologic therapies that can be used with CPAP therapy have the potential to reduce symptoms and consequences of OSA.

DISCUSSION

The wake-promoting medications modafinil and armodafinil effectively improve residual sleepiness in patients treated with CPAP therapy. Although results are equivocal so far, modafinil and armodafinil may also improve quality of life and global clinical condition in patients with OSA and residual sleepiness treated with CPAP therapy. Pharmacologic therapies also have the potential to be used with CPAP therapy to minimize cardiovascular perturbations and risk of cardiovascular disease. Preliminary studies suggest that inhibition of the enzyme xanthine oxidase and inhibition of sympathetic nervous system overactivity may have therapeutic potential to reduce cardiovascular harm in patients with OSA.

CONCLUSION

Future studies of pharmacologic therapies to reduce symptoms and cardiovascular consequences of OSA should be increasingly performed as our understanding of the mechanisms mediating the adverse effects of OSA continues to evolve.

Endothelial Ca+-activated K+ channels in normal and impaired EDHF-dilator responses--relevance to cardiovascular pathologies and drug discovery

The arterial endothelium critically contributes to blood pressure control by releasing vasodilating autacoids such as nitric oxide, prostacyclin and a third factor or pathway termed 'endothelium-derived hyperpolarizing factor' (EDHF). The nature of EDHF and EDHF-signalling pathways is not fully understood yet. However, endothelial hyperpolarization mediated by the Ca(2+)-activated K(+) channels (K(Ca)) has been suggested to play a critical role in initializing EDHF-dilator responses in conduit and resistance-sized arteries of many species including humans. Endothelial K(Ca) currents are mediated by the two K(Ca) subtypes, intermediate-conductance K(Ca) (KCa3.1) (also known as, a.k.a. IK(Ca)) and small-conductance K(Ca) type 3 (KCa2.3) (a.k.a. SK(Ca)). In this review, we summarize current knowledge about endothelial KCa3.1 and KCa2.3 channels, their molecular and pharmacological properties and their specific roles in endothelial function and, particularly, in the EDHF-dilator response. In addition we focus on recent experimental evidences derived from KCa3.1- and/or KCa2.3-deficient mice that exhibit severe defects in EDHF signalling and elevated blood pressures, thus highlighting the importance of the KCa3.1/KCa2.3-EDHF-dilator system for blood pressure control. Moreover, we outline differential and overlapping roles of KCa3.1 and KCa2.3 for EDHF signalling as well as for nitric oxide synthesis and discuss recent evidence for a heterogeneous (sub) cellular distribution of KCa3.1 (at endothelial projections towards the smooth muscle) and KCa2.3 (at inter-endothelial borders and caveolae), which may explain their distinct roles for endothelial function. Finally, we summarize the interrelations of altered KCa3.1/KCa2.3 and EDHF system impairments with cardiovascular disease states such as hypertension, diabetes, dyslipidemia and atherosclerosis and discuss the therapeutic potential of KCa3.1/KCa2.3 openers as novel types of blood pressure-lowering drugs.

Currying the heart: curcumin and cardioprotection

Curcumin (diferuoylmethane) is the active ingredient of turmeric (curcuma longa). There has been a surge of research in its anti-inflammatory and antioxidative properties, and its cardiovascular effects. A host of studies in in vitro and in vivo models of cardiac injury show that curcumin treatment reduces reactive oxygen species generation, monocyte adhesion to activated endothelial cells, and phosphorylation of c-Jun N-terminal kinase, p38 mitogen activated protein kinase and signal transducer and activator of transcription-3, and subsequent downstream signals. These alterations lead to preservation of myocardial function following ischemic or biochemical insult to the heart. Recent studies in models of pressure overload show that curcumin can reduce cardiac remodeling by altering reninangiotensin-system-transforming growth factor beta1 and collagen axis. Studies need to be done in humans to define the potential of curcumin in limitation of cardiac injury and preservation of cardiac function following ischemia.

Mechanisms of flavonoid protection against myocardial ischemia-reperfusion injury

Flavonoids have long been acknowledged for their unique antioxidant properties, and possess other activities that may be relevant to heart ischemia-reperfusion. They may prevent production of oxidants (e.g. by inhibition of xanthine oxidase and chelation of transition metals), inhibit oxidants from attacking cellular targets (e.g. by electron donation and scavenging activities), block propagation of oxidative reactions (by chain-breaking antioxidant activity), and reinforce cellular antioxidant capacity (through sparing effects on other antioxidants and inducing expression of endogenous antioxidants). Flavonoids also possess anti-inflammatory and anti-platelet aggregation effects through inhibiting relevant enzymes and signaling pathways, resulting ultimately in lower oxidant production and better re-establishment of blood in the ischemic zone. Finally, flavonoids are vasodilatory through a variety of mechanisms, one of which is likely interaction with ion channels. These multifaceted activities of flavonoids raise their utility as possible therapeutic interventions to ameliorate ischemia-reperfusion injury.

Bivalirudin decreases NO bioavailability by vascular immobilization of myeloperoxidase

Bivalirudin, a direct thrombin inhibitor, has emerged as an important alternative to heparin in patients undergoing percutaneous coronary intervention. However, it remains elusive if potentially adverse extracoagulant properties are responsible for the fact that its favorable effects in clinical studies are mainly driven by a reduction in bleeding events. The aim of the current study was to determine the effects and mechanisms of acute treatment with bivalirudin in comparison to heparin on NO bioavailability, an important factor for the pathogenesis of ischemic events. In particular, we studied the interaction between bivalirudin and myeloperoxidase (MPO), a leukocyte-derived enzyme that consumes endothelial-derived nitric oxide (NO), modifies a variety of biological targets, and thus affects the integrity of the vessel wall. In patients undergoing elective percutaneous coronary intervention, bivalirudin, in contrast to heparin, exhibited a significant decrease in plasma MPO levels (p = 0.03) accompanied by a deterioration of flow-mediated dilation (p = 0.02), a surrogate for endothelial NO bioavailability. In vitro experiments revealed avid binding of bivalirudin to both bovine aortic endothelial cells (BAEC) and MPO. Methylation of bivalirudin carboxyl groups at the carboxyl-terminal end revealed the specific binding site of bivalirudin to MPO. Bivalirudin-facilitated binding of MPO to BAEC resulted also in functional changes in terms of increased NO consumption as well as enhanced MPO-mediated redox modifications. These results illustrate dichotomous extracoagulant properties of heparins and thrombin inhibitors and suggest that bivalirudin acutely impairs endothelial NO bioavailability, thereby underscoring the potentially critical role of MPO as a mediator of vascular function.

Effects of oral niacin on endothelial dysfunction in patients with coronary artery disease: results of the randomized, double-blind, placebo-controlled INEF study

High-density-lipoproteins-cholesterol (HDL-C) is invertedly related to the incidence of cardiovascular events. Recent studies suggest that HDL-C directly improves endothelial function. Nicotinic acid (niacin) effectively raises serum HDL-C. We therefore hypothesized that treatment with niacin improves endothelial dysfunction in patients with coronary artery disease (CAD). One hundred seven patients with CAD were randomly assigned to double-blinded treatment for 12 weeks with extended-release (ER)-niacin 1000 mg/day (N) or placebo (C), respectively. Flow-mediated dilation (FMD) of the brachial artery, nitroglycerin-mediated endothelium-independent dilation (NMD) and serum lipid concentrations were measured before and after treatment. Triglycerides (P=0.013), low-density-lipoprotein-cholesterol (LDL-C) (P=0.013) and HDL-C (P<0.0001) were altered by N compared to C. Niacin treatment was without effect on FMD or NMD, respectively, compared to placebo. However, post-hoc subgroup analysis revealed an improvement in FMD in patients with low HDL-C at baseline (absolute change in FMD (mean+/-S.D.) N: +3.25+/-3.88%, C: +1.03+/-2.71% in low tertile HDL-C <or=45 mg/dl. P=0.047). The present findings indicate that ER-niacin treatment improves endothelial dysfunction in patients with CAD and low HDL-C, but not with normal HDL-C.

Comparison of atorvastatin versus fenofibrate in reaching lipid targets and influencing biomarkers of endothelial damage in patients with familial combined hyperlipidemia

Statins and fibrates have different effects on lipid abnormalities of familial combined hyperlipidemia (FCHL); thus, the selection of the first-line drug is troublesome. We evaluated to what extent monotherapy with a potent statin is more effective than fibrate in reaching the recommended lipid targets in FCHL. Fifty-six patients were randomized to receive optimal dosage of atorvastatin (n = 27) or 200 mg/d micronized fenofibrate (n = 29) for 24 weeks. To reach the optimal dosage, atorvastatin was up-titrated at each follow-up visit if low-density lipoprotein (LDL) cholesterol >130 mg/dL (>100 mg/dL in patients with coronary or cerebrovascular disease). The effects of fenofibrate and atorvastatin on lipoprotein fractions as well as on plasma levels of endothelin-1 (ET-1) and adrenomedullin (AM) were also evaluated. At end of trial, a greater proportion of patients on atorvastatin (average dosage, 20.8 mg/d) reached lipid targets in comparison with those on fenofibrate (64% vs 32.1%, P = .02). Atorvastatin was significantly more effective in reducing total cholesterol, LDL cholesterol, apolipoprotein B, and non-high-density lipoprotein (HDL) cholesterol. Conversely, triglycerides decreased and HDL increased more during fenofibrate. Nevertheless, atorvastatin produced a marked reduction in very low-density lipoprotein and very low-density lipoprotein remnants. Atorvastatin lowered all LDL subtypes, although fenofibrate appeared to be more effective on denser LDL. Compared with 43 normolipemic controls, FCHL patients presented increased baseline plasma levels of ET-1 (P = .007) but not of AM. Fenofibrate, but not atorvastatin, significantly lowered ET-1 levels by 16.7% (P < .05). Neither drug significantly affected plasma concentrations of AM. In summary, although fenofibrate showed superiority in raising HDL and reducing ET-1, atorvastatin was more effective in reaching lipid targets in FCHL so that it can be proposed as the first-line option in the management of this atherogenic hyperlipidemia.

Do ATP and NO interact in the CNS?

Enzymatically derived NO and extracellular ATP are receiving greater attention due to their role as messengers in the CNS during different physiological and pathological processes. Ionotropic (P2XR) and metabotropic (P2YR) purinergic receptors mediate ATP effects and are present throughout the body. Particularly P2XR are crucial for brain plasticity mechanisms, and are involved in the pathogenesis of different CNS illnesses. NO does not have a specific receptor and its actions are directly dependent on the production on demand by different nitric oxide synthase isoforms. NO synthesizing enzymes are present virtually in all tissues, and NO influences multifarious physiological and pathological functions. Interestingly, various are the tissue and organs modulated by both ATP and NO, such as the immune, brain and vascular systems. Moreover, direct interactions between purinergic and nitrergic mechanisms outside the CNS are well documented, with several studies also indicating that ATP and NO do participate to the same CNS functions. In the past few years, further experimental evidence supported the physiological and pathological relevance of ATP and NO direct interactions in the CNS. The aim of the present review is to provide an account of the available information on the interplay between purinergic and nitrergic systems, focussing on the CNS. The already established relevance of ATP and NO in different pathological processes would predict that the knowledge of ATP/NO cross-talk mechanisms would support pharmacological approaches toward the development of novel ATP/NO combined pharmacological agents.

Effect of statin therapy on early return of potency after nerve sparing radical retropubic prostatectomy

PURPOSE

We prospectively investigated whether postoperative statin use would contribute to earlier recovery of erectile function in men who underwent bilateral nerve sparing radical retropubic prostatectomy for clinically localized prostate cancer.

MATERIALS AND METHODS

A total of 50 potent men without hypercholesterolemia undergoing bilateral nerve sparing radical retropubic prostatectomy for clinically localized prostate cancer were prospectively randomized into 2 equal groups. Group 1 patients were instructed to ingest only 50 mg sildenafil per day if needed following hospital discharge after radical retropubic prostatectomy. Group 2 patients were prescribed atorvastatin at a dose of 10 mg daily from postoperative days 1 to 90 and they were also instructed to ingest sildenafil, as in group 1. Patient status regarding potency and adverse events were assessed 6 months after surgery.

RESULTS

The 2 groups demonstrated no significant differences regarding various baseline factors, including International Index of Erectile Function-5 scores. Group 2 had a significantly higher postoperative International Index of Erectile Function-5 score than group 1 at 6 months postoperatively (p = 0.003). Meanwhile, as judged by a preset definition, the incidence of potent patients 6 months after prostatectomy was 26.1% in group 1 and 55% in group 2 (p = 0.068). Also, 17.4% and 40% of the men reported achieving intercourse by vaginal penetration without a phosphodiesterase 5 inhibitor in groups 1 and 2, respectively (p = 0.172). No serious adverse events associated with medication were reported.

CONCLUSIONS

Postoperative treatment with atorvastatin in men who report normal erectile function preoperatively may contribute to earlier recovery of erectile function after nerve sparing radical retropubic prostatectomy.