Effect of resveratrol on endothelial cell function: Molecular mechanisms

Nutraceuticals in the management of autonomic function and related disorders: A comprehensive review

Nutraceuticals have been described as phytocomplexes when derived from foods of plant origin or a pool of secondary metabolites when derived from foods of animal origin, which are concentrated and administered in an appropriate form and can promote beneficial health effects in the prevention/treatment of diseases. Considering that pharmaceutical medications can cause side effects, there is a growing interest in using nutraceuticals as an adjuvant therapeutic tool for several disorders involving autonomic dysfunction, such as obesity, atherosclerosis and other cardiometabolic diseases. This review summarizes and discusses the evidence from the literature on the effects of various nutraceuticals on autonomic control, addressing the gut microbiota modulation, production of secondary metabolites from bioactive compounds, and improvement of physical and chemical properties of cell membranes. Additionally, the safety of nutraceuticals and prospects are discussed. Probiotics, resveratrol, quercetin, curcumin, nitrate, inositol, L-carnosine, and n-3 polyunsaturated fatty acids (n-3 PUFAs) are among the nutraceuticals most studied to improve autonomic dysfunction in experimental animal models and clinical trials. Further human studies are needed to elucidate the effects of nutraceuticals formulated of multitarget compounds and their underlying mechanisms of action, which could benefit conditions involving autonomic dysfunction.

Resveratrol supplementation efficiently improves endothelial health: A systematic review and meta-analysis of randomized controlled trials

We perform a systematic review and meta-analysis of randomized controlled trials (RCTs) to quantify the effect of resveratrol supplementation on endothelial function. A comprehensive search was performed in electronic databases including PubMed, Scopus, Web of Science, and Cochrane Library up to February 2021 with no limitation in time and language. A meta-analysis of eligible studies was performed using a random-effects model to estimate the pooled effect size of flow-mediated dilation (FMD), intracellular adhesion molecule-1 (ICAM-1), vascular adhesion molecule-1 (VCAM-1), fibrinogen, and plasminogen activator inhibitor-1 (PAI-1). In total, 21 arms from 17 studies were included. The meta-analysis results showed that resveratrol significantly change the concentrations of FMD (WMD: 1.43%; 95% CI: 0.98 to 1.88, p < .001) and ICAM-1 (WMD: -7.09 ng/ml, 95% CI: -7.45 to -6.73, p < .001). However, VCAM-1, fibrinogen, and PAI-1 did not change significantly after resveratrol supplementation. In conclusion, the results of this study suggest that resveratrol supplementation can improve endothelial function which could be important, especially in patients with cardiovascular diseases.

Aortic Stiffness in L-NAME Treated C57Bl/6 Mice Displays a Shift From Early Endothelial Dysfunction to Late-Term Vascular Smooth Muscle Cell Dysfunction

Introduction and Aims: Endothelial dysfunction is recognized as a cardiovascular aging hallmark. Administration of nitric oxide synthase blocker N-Ω-Nitro-L-arginine methyl ester hydrochloride (L-NAME) constitutes a well-known small animal model of cardiovascular aging. Despite extensive phenotypic characterization, the exact aortic function changes in L-NAME treated mice are largely unknown. Therefore, this study presents a longitudinal characterization of the aortic reactivity and biomechanical alterations in L-NAME treated C57Bl/6 mice.

Methods and Results: Male C57Bl/6 mice were treated with L-NAME (0.5 mg/ml drinking water) for 1, 2, 4, 8, or 16 weeks. Peripheral blood pressure measurement (tail-cuff) and transthoracic echocardiograms were recorded, showing progressive hypertension after 4 weeks of treatment and progressive cardiac hypertrophy after 8–16 weeks of treatment. Aortic stiffness was measured in vivo as aortic pulse wave velocity (aPWV, ultrasound) and ex vivo as Peterson modulus (E_p). Aortic reactivity and biomechanics were investigated ex vivo in thoracic aortic rings, mounted isometrically or dynamically-stretched in organ bath set-ups. Aortic stiffening was heightened in L-NAME treated mice after all treatment durations, thereby preceding the development of hypertension and cardiac aging. L-NAME treatment doubled the rate of arterial stiffening compared to control mice, and displayed an attenuation of the elevated aortic stiffness at high distending pressure, possibly due to late-term reduction of medial collagen types I, III, and IV content. Remarkably, endothelial dysfunction, measured by acetylcholine concentration-response stimulation in precontracted aortic rings, was only observed after short-term (1–4 weeks) treatment, followed by restoration of endothelial function which coincided with increased phosphorylation of endothelial nitric oxide synthase (S¹¹⁷⁷). In the late-disease phase (8–16 weeks), vascular smooth muscle cell (VSMC) dysfunction developed, including increased contribution of voltage-dependent calcium channels (assessed by inhibition with diltiazem), basal VSMC cytoplasmic calcium loading (assessed by removal of extracellular calcium), and heightened intracellular contractile calcium handling (assessed by measurement of sarcoplasmic reticulum-mediated transient contractions).

Conclusion: Arterial stiffness precedes peripheral hypertension and cardiac hypertrophy in chronic L-NAME treated male C57Bl/6 mice. The underlying aortic disease mechanisms underwent a distinct shift from early endothelial dysfunction to late-term VSMC dysfunction, with continued disease progression.

Extremely low frequency electromagnetic stimulation reduces ischemic stroke volume by improving cerebral collateral blood flow

Extremely low frequency electromagnetic stimulation (ELF-EMS) has been considered as a neuroprotective therapy for ischemic stroke based on its capacity to induce nitric oxide (NO) signaling. Here, we examined whether ELF-EMS reduces ischemic stroke volume by stimulating cerebral collateral perfusion. Moreover, the pathway responsible for ELF-EMS-induced NO production was investigated. ELF-EMS diminished infarct growth following experimental stroke in collateral-rich C57BL/6 mice, but not in collateral-scarce BALB/c mice, suggesting that decreased lesion sizes after ELF-EMS results from improved collateral blood flow. In vitro analysis demonstrated that ELF-EMS increased endothelial NO levels by stimulating the Akt-/eNOS pathway. Furthermore, ELF-EMS augmented perfusion in the hind limb of healthy mice, which was mediated by enhanced Akt-/eNOS signaling. In healthy C57BL/6 mouse brains, ELF-EMS treatment increased cerebral blood flow in a NOS-dependent manner, whereas no improvement in cerebrovascular perfusion was observed in collateral-sparse BALB/c mice. In addition, ELF-EMS enhanced cerebral blood flow in both the contra- and ipsilateral hemispheres of C57BL/6 mice subjected to experimental ischemic stroke. In conclusion, we showed that ELF-EMS enhances (cerebro)vascular perfusion by stimulating NO production, indicating that ELF-EMS could be an attractive therapeutic strategy for acute ischemic stroke by improving cerebral collateral blood flow.

Basal Vascular Smooth Muscle Cell Tone in eNOS Knockout Mice Can Be Reversed by Cyclic Stretch and Is Independent of Age

Introduction and Aims: Endothelial nitric oxide synthase (eNOS) knockout mice develop pronounced cardiovascular disease. In the present study, we describe the alterations in aortic physiology and biomechanics of eNOS knockout and C57Bl/6 control mice at 2–12 months of age, including a thorough physiological investigation of age and cyclic stretch-dependent VSMC contractility and aortic stiffness.

Methods and Results: Peripheral blood pressure and aortic pulse wave velocity were measured in vivo, and aortic biomechanical studies and isometric contractions were investigated ex vivo. Age-dependent progression of aortic stiffness, peripheral hypertension, and aortic contractility in eNOS knockout mice was absent, attenuated, or similar to C57Bl/6 control mice. Voltage-gated calcium channel (VGCC)-dependent calcium influx inversely affected isometric contraction and aortic stiffening by α₁-adrenergic stimulation in eNOS knockout mice. Baseline aortic stiffness was selectively reduced in eNOS knockout mice after ex vivo cyclic stretch exposure in an amplitude-dependent manner, which prompted us to investigate cyclic stretch dependent regulation of aortic contractility and stiffness. Aortic stiffness, both in baseline conditions and after activation of vascular smooth muscle cell (VSMC) contraction, was reduced with increasing cyclic stretch amplitude. This cyclic stretch dependency was attenuated with age, although aged eNOS knockout mice displayed better preservation of cyclic stretch-dependency compared to C57Bl/6 control mice. Store operated calcium entry-medicated aortic stiffening as induced by inhibiting sarcoplasmic reticulum calcium ATPase pumps with 10 µM CPA was most pronounced in the aorta of aged mice and at low cyclic stretch amplitude, but independent of eNOS. Basal aortic tonus and VSMC depolarization were highly dependent on eNOS, and were most pronounced at low cyclic stretch, with attenuation at increasing cyclic stretch amplitude.

Conclusion: eNOS knockout mice display attenuated progression of arterial disease as compared to C57Bl/6 control mice. Basal VSMC tone in eNOS knockout mice could be reduced by ex vivo exposure to cyclic stretch through stretch-dependent regulation of cytosolic calcium. Both baseline and active aortic stiffness were highly dependent on cyclic stretch regulation, which was more pronounced in young versus aged mice. Other mediators of VSMC contraction and calcium handling were dependent on cyclic stretch mechanotransduction, but independent of eNOS.

Endothelial Progenitor Cells Dysfunctions and Cardiometabolic Disorders: From Mechanisms to Therapeutic Approaches

Metabolic syndrome (MetS) is a cluster of several disorders, such as hypertension, central obesity, dyslipidemia, hyperglycemia, insulin resistance and non-alcoholic fatty liver disease. Despite health policies based on the promotion of physical exercise, the reduction of calorie intake and the consumption of healthy food, there is still a global rise in the incidence and prevalence of MetS in the world. This phenomenon can partly be explained by the fact that adverse events in the perinatal period can increase the susceptibility to develop cardiometabolic diseases in adulthood. Individuals born after intrauterine growth restriction (IUGR) are particularly at risk of developing cardiovascular diseases (CVD) and metabolic disorders later in life. It has been shown that alterations in the structural and functional integrity of the endothelium can lead to the development of cardiometabolic diseases. The endothelial progenitor cells (EPCs) are circulating components of the endothelium playing a major role in vascular homeostasis. An association has been found between the maintenance of endothelial structure and function by EPCs and their ability to differentiate and repair damaged endothelial tissue. In this narrative review, we explore the alterations of EPCs observed in individuals with cardiometabolic disorders, describe some mechanisms related to such dysfunction and propose some therapeutical approaches to reverse the EPCs dysfunction.

Fine wine or sour grapes? A systematic review and meta-analysis of the impact of red wine polyphenols on vascular health

PURPOSE

Red wine polyphenols (RWP) are plant-based molecules that have been extensively studied in relation to their protective effects on vascular health in both animals and humans. The aim of this review was to quantify and compare the efficacy of RWP and pure resveratrol on outcomes measures of vascular health and function in both animals and humans.

METHODS

Comprehensive database searches were carried out through PubMed, Web of Science and OVID for randomised, placebo-controlled studies in both animals and humans. Meta-analyses were carried out on acute and chronic studies of RWP in humans, alongside sub-group analysis where possible. Risk-of-bias assessment was carried out for all included studies based on randomisation, allocation, blinding, outcome data reporting, and other biases.

RESULTS

48 animal and 37 human studies were included in data extraction following screening. Significant improvements in measures of blood pressure and vascular function following RWP were seen in 84% and 100% of animal studies, respectively. Human studies indicated significant improvements in systolic blood pressure overall (- 2.6 mmHg, 95% CI: [- 4.8, - 0.4]), with a greater improvement in pure-resveratrol studies alone (- 3.7 mmHg, 95% CI: [- 7.3, - 0.0]). No significant effects of RWP were seen in diastolic blood pressure or flow-mediated dilation (FMD) of the brachial artery.

CONCLUSION

RWP have the potential to improve vascular health in at risk human populations, particularly in regard to lowering systolic blood pressure; however, such benefits are not as prevalent as those observed in animal models.

Effect of resveratrol combined with atorvastatin on re-endothelialization after drug-eluting stents implantation and the underlying mechanism

AIMS

To explore whether the combination of atorvastatins and resveratrol is superior to each individual drug alone regarding re-endothelialization after drug-eluting stents (DESs) implantation.

MATERIALS AND METHODS

Ninety-four rabbits were randomized into control, atorvastatin, resveratrol, and combined medication groups. Abdominal aorta injury was induced via ballooning, followed by DES implantation. Neointimal formation and re-endothelialization after stent implantation were assessed via optical coherence tomography and scanning electron microscopy. The effects of resveratrol and atorvastatin on bone marrow-derived mesenchymal derived stem cells (BMSCs) were assessed.

KEY FINDINGS

Compared with the findings in the resveratrol and atorvastatin groups, the neointimal area and mean neointimal thickness were greater in the combined medication group, which also exhibited improved re-endothelialization. Compared with the effects of monotherapy, combined treatment further protected BMSCs against rapamycin-induced apoptosis and improved cell migration. Combined medication significantly upregulated Akt, p-Akt, eNOS, p-eNOS, and CXCR4 expression in BMSCs compared with the effects of monotherapy, and these effects were abolished by the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002.

SIGNIFICANCE

The combination of atorvastatin and resveratrol has the potential of accelerating re-endothelialization after stent implantation, reducing the risk of thrombosis and improving the safety of DESs.

Tetramethoxystilbene-Loaded Liposomes Restore Reactive-Oxygen-Species-Mediated Attenuation of Dilator Responses in Rat Aortic Vessels Ex vivo

The methylated analogue of the polyphenol resveratrol (RV), 2,3′,4,5′-tetramethoxystilbene (TMS) displays potent antioxidant properties and is an effective cytochrome P450 (CYP) 1B1 inhibitor. The bioavailability of TMS is low. Therefore, the use of liposomes for the encapsulation of TMS is a promising delivery modality for enhanced uptake into tissues. We examined the effect of delivery of TMS in liposomes on the restoration of vasodilator responses of isolated aortic vessels after acute tension elevation ex vivo. Aortic vessels from young male Wistar rats were isolated, and endothelial-dependent (acetylcholine, ACh) and -independent (sodium nitroprusside, SNP) responses assessed. Acute tension elevation (1 h) significantly reduced ACh dilator responses, which were restored following incubation with superoxide dismutase or apocynin (an NADPH oxidase inhibitor). Incubation with TMS-loaded liposomes (mean diameter 157 ± 6 nm; PDI 0.097) significantly improved the attenuated dilator responses following tension elevation, which was sustained over a longer period (4 h) when compared to TMS solution. Endothelial denudation or co-incubation with L-NNA (Nω-nitro-l-arginine; nitric oxide synthase inhibitor) resulted in loss of dilator function. Our findings suggest that TMS-loaded liposomes can restore attenuated endothelial-dependent dilator responses induced by an oxidative environment by reducing NADPH-oxidase-derived ROS and potentiating the release of the vasodilator nitric oxide. TMS-loaded liposomes may be a promising therapeutic strategy to restore vasodilator function in vascular disease.

A pH-Induced Reversible Assembly System with Resveratrol-Controllable Loading and Release for Enhanced Tumor-Targeting Chemotherapy

In this report, we present a pH-induced reversible assembly system (PIRAS) based on ferritin (Ft) for targeted tumor therapy. It has been developed to easily load and release of the anticancer drug resveratrol (RV), based on its natural pH-sensitivity and unique hollow cavity of Ft. A tumor-specific target peptide Arg-Gly-Asp (RGD) was conjugated onto the surface of RV-loaded Ft (RV@Ft), to form biocompatible nanoparticles (RV@Ft-RGD). The pH-sensitivity of Ft allows it to be denatured into a hollow porous nanosphere under acidic condition and renatured into a sealed hollow nanosphere under neutral condition. Using pH manipulation, RV@Ft-RGD, with a ~ 21 nm diameter, showed a high RV loading ratio of 79.6%. pH-triggered RV release was then measured at a ratio of 50.3% at pH5.0 over 24 h. Under neutral condition, the RV@Ft-RGD showed excellent stability over 20 days. Confocal fluorescence imaging showed that RV@Ft-RGD had a high cell uptake ratio and co-localization with the lysosome, mainly due to the RGD-mediated target effect. Based on the high drug loading, pH-triggered release, and tumor cell targeting effect, RV@Ft-RGD showed great cell-killing ability in vitro and in vivo. The biocompatibility in vitro and in vivo was also demonstrated to be excellent, without systematic toxicity. The design concept of PIRAS based on Ft significantly inhibits tumor growth and simultaneously further broadens the application of Ft in nanomedicine.

The Postprandial Appearance of Features of Cardiometabolic Risk: Acute Induction and Prevention by Nutrients and Other Dietary Substances

The purpose of this review is to provide an overview of diets, food, and food components that affect postprandial inflammation, endothelial function, and oxidative stress, which are related to cardiometabolic risk. A high-energy meal, rich in saturated fat and sugars, induces the transient appearance of a series of metabolic, signaling and physiological dysregulations or dysfunctions, including oxidative stress, low-grade inflammation, and endothelial dysfunction, which are directly related to the amplitude of postprandial plasma triglycerides and glucose. Low-grade inflammation and endothelial dysfunction are also known to cluster together with insulin resistance, a third risk factor for cardiovascular diseases (CVD) and type-II diabetes, thus making a considerable contribution to cardiometabolic risk. Because of the marked relevance of the postprandial model to nutritional pathophysiology, many studies have investigated whether adding various nutrients and other substances to such a challenge meal might mitigate the onset of these adverse effects. Some foods (e.g., nuts, berries, and citrus), nutrients (e.g., l-arginine), and other substances (various polyphenols) have been widely studied. Reports of favorable effects in the postprandial state have concerned plasma markers for systemic or vascular pro-inflammatory conditions, the activation of inflammatory pathways in plasma monocytes, vascular endothelial function (mostly assessed using physiological criteria), and postprandial oxidative stress. Although the literature is fragmented, this topic warrants further study using multiple endpoints and markers to investigate whether the interesting candidates identified might prevent or limit the postprandial appearance of critical features of cardiometabolic risk.

Effects of resveratrol on laminar shear stress-induced mitochondrial biogenesis in human vascular endothelial cells

[Purpose]

The purpose of the study was to determine the combined effects of resveratrol supplementation with high-flow LSS on mitochondrial biogenesis in human vascular endothelial cells.

[Methods]

Cultured human umbilical vein endothelial cells were treated with 20 μM of RSV. For the shear experiments, cells grown to a >90% confluence were exposed to physiological levels of LSS (5 to 20 dyne/cm2) for 12 to 36 hours using a cone and plate shear apparatus. Gene expressions were analyzed by western blotting.

[Results]

Depletion of mitochondrial integrity was directly associated with increase in endothelial activation/dysfunction. The expressions of mitochondrial biogenesis regulator genes, such as SIRT1, PGC-1α, and TFAM, and the mitochondrial contents were significantly increased after treatment with both resveratrol and high-flow LSS for 12 hours. However, supplementation of resveratrol to high-flow LSS for a prolonged duration had no synergistic effect on the levels of mitochondrial biogenesis regulator gene expressions and mitochondrial content compared to the LSS treatment alone.

[Conclusion]

The present study demonstrated that the supplementation of resveratrol to high-flow LSS has no synergistic effects on enhancing mitochondrial integrity in human vascular endothelial cells.

(-)-Epicatechin induced reversal of endothelial cell aging and improved vascular function: underlying mechanisms

The consumption of cocoa products rich in (-)-epicatechin is associated with reduced cardiovascular risk and improved vascular function. However, little is known about (-)-epicatechin's effects on aged endothelium. In order to characterize the health restoring effects of (-)-epicatechin on aged endothelium and identify the underlying mechanisms, we utilized high passage number (i.e. aged) bovine coronary artery endothelial cells and aortas of 3 and 18 month old rats. We evaluated cell senescence (β-galactosidase), nitric oxide (NO) production through the endothelial nitric oxide synthase pathway, mitochondria related endpoints, citrate synthase activity and vascular relaxation. Cells were treated with water or (-)-epicatechin (1 μM) for 48 h and rats orally with either water or (-)-epicatechin (1 mg kg-1 day-1) for 15 days. Senescence associated β-galactosidase levels doubled in aged cells while those treated with (-)-epicatechin only evidenced an ∼40% increase. NO levels in cells decreased by ∼33% with aging and (-)-epicatechin normalized them. Endothelial nitric oxide synthase phosphorylation levels paralleled these results. Aging increased total protein and synthase acetylation levels and (-)-epicatechin partially restored them to those of young cells by stimulating sirtuin-1 binding to the synthase. Phosphorylated sirtuin-1, mitofilin, oxidative phosphorylation complexes and transcriptional factor for mitochondria were reduced by ∼40% with aging and were restored by (-)-epicatechin. (-)-Epicatechin enhanced acetylcholine induced aged aorta vasodilation and stimulated NO levels while reducing blood pressure. In conclusion, (-)-epicatechin reverses endothelial cell aging and restores key control elements of vascular function. These actions may partly explain the epidemiological evidence for the beneficial effects of cocoa consumption on the incidence of cardiac and vascular diseases.

Myeloid angiogenic cells exhibit impaired migration, reduced expression of endothelial markers, and increased apoptosis in idiopathic pulmonary arterial hypertension 1

Idiopathic pulmonary arterial hypertension (IPAH) is a rare and devastating condition. There is no known cure for IPAH, and current treatment options are not always effective. Autologous myeloid angiogenic cells (MACs) have been explored as a novel therapy for IPAH, but preliminary data from clinical trials show limited beneficial effects. A complete understanding of IPAH MAC function remains elusive. This study was designed to comprehensively compare cell function between IPAH MACs and healthy control MACs. MACs were procured through the culture of peripheral blood mononuclear cells in endothelial selective medium for 7 days. Compared with healthy MACs, IPAH MACs exhibited (1) significantly lower levels of endothelial markers as shown by fluorescence microscopy; (2) a markedly higher rate of apoptosis under both normal culture condition and serum starvation as shown by the TUNEL assay; (3) significantly decreased migration towards vascular endothelial growth factor as shown by a modified Boyden chamber migration assay; and (4) similar vascular endothelial growth factor and endothelial nitric oxide synthase mRNA levels as shown by reverse transcription quantitative PCR. In conclusion, various aspects of IPAH MAC function are impaired. To achieve greater therapeutic benefits, pharmacologic and (or) genetic manipulations to improve IPAH MAC function, particularly to promote cell survival and migration, are warranted.

Resveratrol protects late endothelial progenitor cells from TNF-α-induced inflammatory damage by upregulating Krüppel-like factor-2

Cardiovascular risk factors can negatively influence late endothelial progenitor cell (EPCs) number and functions, thus EPCs biology is a clinical implications for cardiovascular diseases. The present study aimed to investigate the potential protective effects of resveratrol (RES) on tumor necrosis factor (TNF)-α-induced inflammatory damage in late endothelial progenitor cells (EPCs) and to elucidate the underlying mechanisms. Late EPCs at passages 3–5 were pretreated with RES at a concentration of 20 µmol/l for 12 h and subsequently incubated with TNF-α (10 ng/ml) for 24 h. The adhesion, migration, proliferation and vasculogenesis of EPCs were subsequently detected. Furthermore, the mRNA expression levels of intercellular adhesion molecule-1 (ICAM-1) and monocyte chemoattractant protein-1 (MCP-1) were measured by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Nitric oxide (NO) levels in the supernatant were determined using a colorimetric assay kit. Additionally, the mRNA and protein expression of Krüppel-like factor-2 (KLF2) was determined by RT-qPCR and western blot analysis, respectively. The results indicated that TNF-α markedly inhibited the proliferation, adhesion, migration and vasculogenesis of late EPCs. However, RES ameliorated the effects induced by TNF-α. Furthermore, exposure of EPCs to TNF-α decreased the levels of NO secretion and KLF2 expression at the mRNA and protein levels, but upregulated the levels of inflammatory factors, including ICAM-1 and MCP-1, compared with the control group. RES significantly inhibited TNF-α-induced inflammatory damage through upregulation of KLF2 expression and downregulation of the expression of ICAM-1 and MCP-1. In conclusion, RES may exert protective effects on the cardiovascular system, as demonstrated by the amelioration of TNF-α-induced inflammation in EPCs following RES treatment, and may therefore be used in the future for the prevention of cardiovascular disease.

Resveratrol protects Leydig cells from nicotine-induced oxidative damage through enhanced autophagy

Some studies have revealed that nicotine can damage the male reproductive system through various means including oxidative stress, which is a primary factor in the pathogenesis of male infertility. The strong anti-oxidative capacity of resveratrol has been demonstrated previously, but its role in the context of male reproduction remains inconclusive. To explore the biological role of resveratrol in protecting male reproductive function and the potential underlying mechanism, nicotine-induced Leydig cells were used as a cell model of oxidative damage. The data showed that resveratrol treatment increased cell viability, SOD activity and anti-apoptotic activity in nicotine-stressed Leydig cells. This effect was accompanied by the upregulation of autophagy, which was illustrated by MDC-LysoTracker red staining. Moreover, pretreating with 3-methyladenine (3-MA), an autophagy inhibitor, attenuated resveratrol-induced Leydig cells autophagy and promoted apoptosis. Apart from this, resveratrol enhanced AMPK phosphorylation but reduced mTOR phosphorylation. Subsequently, upon inhibiting AMPK phosphorylation by AMPK inhibitors, Leydig cell autophagy induced by resveratrol was obviously abolished. In conclusion, resveratrol may exert its cytoprotective role against oxidative injury by the activation of autophagy via AMPK/mTOR pathway.

Naringenin Attenuates H2O2-Induced Mitochondrial Dysfunction by an Nrf2-Dependent Mechanism in SH-SY5Y Cells

Mitochondria are the major site of ATP production in mammalian cells. Furthermore, these organelles are a source and a target of reactive oxygen species (ROS), such as radical anion superoxide (O₂^-·) and hydrogen peroxide (H₂O₂). The transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) is the master regulator of the mammalian redox biology and controls the expression of antioxidant and phase II detoxifying enzymes in several cell types. Naringenin (NGN, 5,7-dihydroxy-2-(4-hydroxyphenyl)-2,3-dihydrochromen-4-one), a flavanone, exhibits cytoprotective effects by acting as an antioxidant and anti-inflammatory agent. NGN is a potent activator of Nrf2. Nonetheless, it was not examine yet whether NGN would induce mitochondrial protection in cells under redox stress. Therefore, we investigate here whether Nrf2 would be involved in the mitochondrial protection elicited by NGN in SH-SY5Y cells exposed to H₂O₂. We observed that a pretreatment with NGN at 80 µM for 2 h reduced the levels of lipid peroxidation, protein carbonylation, and protein nitration in the membranes of mitochondria obtained from H₂O₂-treated SH-SY5Y cells. Additionally, NGN prevented the H₂O₂-induced impairment in the function of the enzymes aconitase, α-ketoglutarate dehydrogenase, and succinate dehydrogenase. The activites of the complexes I and V, as well as the production of ATP, were restored by NGN. NGN also suppressed the H₂O₂-induced mitochondria-related apoptosis. Interestingly, NGN promoted an increase in the levels of both total and mitochondrial glutathione (GSH). Silencing of Nrf2 abolished the protective effects induced by NGN. Overall, NGN induced mitochondrial protection by an Nrf2-dependent mechanism in H₂O₂-treated SH-SY5Y cells.

Effect of Resveratrol on Modulation of Endothelial Cells and Macrophages for Rapid Vascular Regeneration from Electrospun Poly(ε-caprolactone) Scaffolds

Rapid endothelialization is a key factor that determines the success of small-diameter vascular grafts as an artery substitute in the treatment of cardiovascular diseases. Aimed to facilitate vascular regeneration, we developed a vascular scaffold loaded with resveratrol, which is a natural compound extracted from plants and showed multifaceted effects in cardiovascular protection. The tubular poly(ε-caprolactone) (PCL) scaffold was prepared by electrospinning with resveratrol in the PCL solution. In vitro assay demonstrated that resveratrol could be released from the scaffolds in a sustained and controlled manner. Cell culture results indicated that the migration of endothelial cells (ECs), nitric oxide production, and the ability of tube formation increased in the resveratrol-containing PCL scaffold groups compared with the PCL control. Meanwhile, the level of tumor necrosis factor (TNF)-α, the main proinflammatory factor secreted from macrophages, was reduced, and the messenger RNA expressions of the M2 macrophage-related genes were increased in the resveratrol-containing group. Further, in vivo implantation was performed by replacing rat abdominal aorta. We observed fast endothelialization and enhanced vascular regeneration in rats with resveratrol-containing scaffolds. The presence of resveratrol also induced a large number of M2 macrophages to infiltrate into the graft wall. Taken together, the incorporation of resveratrol into the PCL grafts enhanced the vascular regeneration by modulation of ECs and macrophages.

Resveratrol protects against oxidized low‑density lipoprotein‑induced human umbilical vein endothelial cell apoptosis via inhibition of mitochondrial‑derived oxidative stress

Resveratrol, a natural phytochemical found in grapes and red wine, has been found to possess protective effects against endothelial cell apoptosis and oxidative damage. Oxidized-low density lipoprotein (ox-LDL) can induce apoptosis of endothelial cells, which is an important initial event in several cardiovascular diseases. However, the effect of resveratrol on ox-LDL-induced apoptosis and oxidative damage, and the possible associated mechanisms remain to be elucidated. In the present study, following exposure to ox-LDL, human umbilical vein endothelial cells (HUVECs) were treated with or without resveratrol. Cell viability was examined using Cell Counting Kit-8 and 5-bromo-2′-deoxyuridine uptake assays, respectively. Cell apoptosis was determined by flow cytometry. Apoptosis-associated markers were detected using western blot analysis. Oxidative stress was analyzed using molecular and biochemical approaches. Resveratrol restored ox-LDL-induced HUVEC injury and apoptosis in a dose-dependent manner. In addition, compared with the control group, ox-LDL treatment decreased the B cell lymphoma-2 (Bcl-2)/Bcl-2-associated X protein ratio, mitochondrial membrane potential and activation of superoxide dismutase, and enhanced the release of mitochondrial cytochrome c into the cytoplasm, the activation of caspase and lipid peroxidation. All these alterations were significantly inhibited following treatment with resveratrol. The results demonstrated that resveratrol prevented HUVEC apoptosis through inhibiting mitochondria-derived oxidative damage. These findings may provide a novel mechanism by which resveratrol prevents against endothelial cell apoptosis.

Long-term low dose dietary resveratrol supplement reduces cardiovascular structural and functional deterioration in chronic heart failure in rats

A short-term exposure to resveratrol at high dosages exerts a remarkable cardioprotective effect. Whether a long-term exposure to resveratrol at low dosages that can be obtained through consumption of a resveratrol-rich diet is beneficial to heart diseases is unknown. We tested the effects of a resveratrol-enriched diet on cardiovascular remodeling of chronic heart failure (CHF) in rats resulting from permanent ligation of left coronary artery. Two weeks after surgery, rats were started on either a resveratrol-enriched (R; 5 mg/kg per day; n = 23) or normal (Control; n = 23) diet for next 10 months. Serial echocardiography in Control showed a significant decline in LV ejection fraction, increases in LV end-systolic and end-diastolic volumes, and expansion in myocardial infarct from pre-treatment values. In R, compared with Control, there were substantial improvements in those parameters. End-point LV pressure-volume loop analysis showed a significantly improved LV systolic function and AV-coupling, an index of energy transfer efficacy between the heart and aortic tree, in R compared with Control (p < 0.05). Aortic pulse wave velocity, a measure of arterial stiffness, was significantly lower in R (389 ± 15 cm/s; p < 0.05) compared with Control (489 ± 38 cm/s). These results demonstrated that long-term dietary resveratrol supplement reduces cardiovascular structural and functional deterioration in CHF.

Modulation of the vascular endothelium functioning by dietary components, the role of epigenetics

Rather than being a passive barrier between circulating blood and smooth muscle cells and the underlying tissues, the endothelium is a fundamental functional component of the vasculature, and could be viewed as the largest human endocrine gland/organ, secreting multiple pro-/antiangiogenic factors, cytokines and low-molecular-weight mediators controlling the vascular tone. The location of endothelium, at the interface between the circulation and the tissues, makes this epithelial layer particularly exposed to physical and chemical cues coming from the bloodstream. In response to such stimuli, the endothelium modulates its morphology and functions to maintain vascular homeostasis. Dietary components significantly affect the proper functioning of the endothelium. High-calories and high-fat western diets, in the long term, cause endothelial dysfunction, which is a major contributor to the development of the metabolic syndrome and its pathological consequences, including atherosclerosis, diabetes, and hypertension. On the contrary, plant-derived antioxidant molecules and polyphenols have been shown to exert beneficial effects on endothelial function. Extensive research in the last decade has clearly shown the close relationship between food intake, dietary habits, and gene expression, which is driven by the action of macro- and micronutrients on chromatin regulation. Nutrient-induced chromatin epigenetic modifications via DNA methylation and histone post-translational modifications, especially in the context of the western diet, significantly contribute to the dysregulation of endothelial functioning. Here, we review the current understanding on how dietary components (macronutrients, antioxidants), acting on epigenetic mechanisms, regulate endothelial physiology, and physiopathology. © 2016 BioFactors, 43(1):5-16, 2017.

Protective effects of resveratrol on autologous nucleus pulposus model of radiculopathy

Nucleus pulposus (NP) has been suggested to trigger an autoimmune response if exposed to the immune system, which plays a key role in neuropathic pain. Therefore, appropriate suppression of inflammation is a key factor for treating the radiculopathy caused by intervertebral disk (IVD) degeneration. Resveratrol, a key component of red wine, has been suggested to exhibit anti-inflammatory properties in vitro and in vivo. However, the effects of resveratrol on NP-mediated pain in vivo have not been studied. The aim of the present study was to investigate whether resveratrol may be useful in treating NP-mediated pain in an autologous NP model of radiculopathy. A total of 36 adult male Sprague-Dawley rats were allocated randomly into sham (group I), saline-treated (group II) and resveratrol-treated (group III) groups. Animal behavior in response to non-noxious mechanical stimulation with von Frey filaments was compared at days 0 (baseline), 3, 7, 14 and 21 following surgery. The expression of proinflammatory cytokines such as tumor necrosis factor α (TNF-α) and interleukin-1 (IL-1) were assessed at days 7 and 14. The data showed that resveratrol exhibited an anti-inflammatory effect on the expression of proinflammatory cytokines. Compared with group II, the expression of TNF-α and IL-1 was significantly decreased at each time point in group III. In addition, resveratrol significantly reduced pain behavior triggered by the application of NP tissue on the dorsal root ganglion for up to 14 days. These data suggest that resveratrol has potential for the treatment of NP-mediated pain, indicating a potential clinical application.

Effects of exercise training and resveratrol on vascular health in aging

Cardiovascular disease is a leading cause of death in the western world with aging being one of the strongest predictors of cardiovascular events. Aging is associated with impaired vascular function due to endothelial dysfunction and altered redox balance, partly caused by an increased formation of reactive oxygen species combined with a reduction in the endogenous antioxidant capacity. The consequence of these alterations is a reduced bioavailability of nitric oxide (NO) with implications for aspects such as control of vascular tone and low grade inflammation. However, it is not only aging per se but also the accumulative influence of physical inactivity and other life-style factors, which negatively affect the vascular system. Regular physical activity improves NO bioavailability, the redox balance and the plasma lipid profile and, at a functional level, reduces or even reverses a majority of the observed detrimental effects of aging on vascular function. The effects of aging and physical activity on vascular function are, in part, related to alterations in cellular signaling through sirtuin-1, AMPK and the estrogen receptor. The polyphenol resveratrol can activate these same pathways and has, in animals and in vitro models, been shown to act as a partial mimetic of physical activity. However, support for beneficial effects of resveratrol in human is weak and studies even show that resveratrol supplementation, similarly to supplementation with other antioxidants, can counteract the positive effects of physical activity. Regular physical activity remains the most effective way of maintaining and improving vascular health status and caution should be taken regarding potential interference of supplements on training adaptations.

Resveratrol Enhances Autophagic Flux and Promotes Ox-LDL Degradation in HUVECs via Upregulation of SIRT1

Oxidized low-density lipoprotein- (Ox-LDL-) induced autophagy dysfunction in human vascular endothelial cells contributes to the development of atherosclerosis (AS). Resveratrol (RSV) protects against Ox-LDL-induced endothelium injury. The objective of this study was to determine the mechanisms underlying Ox-LDL-induced autophagy dysfunction and RSV-mediated protection in human umbilical vein endothelial cells (HUVECs). The results showed that Ox-LDL suppressed the expression of sirtuin 1 (SIRT1) and increased LC3-II and sequestosome 1 (p62) protein levels without altering p62 mRNA levels in HUVECs. Pretreatment with bafilomycin A1 (BafA1) to inhibit lysosomal degradation abrogated the Ox-LDL-induced increase in LC3-II protein level. Ox-LDL increased colocalization of GFP and RFP puncta in mRFP-GFP-tandem fluorescent LC3- (tf-LC3-) transfected cells. Moreover, Ox-LDL decreased the expression of mature cathepsin D and attenuated cathepsin D activity. Pretreatment with RSV increased the expression of SIRT1 and LC3-II and increased p62 protein degradation. RSV induced RFP-LC3 aggregation more than GFP-LC3 aggregation. RSV restored lysosomal function and promoted Ox-LDL degradation in HUVECs. All the protective effects of RSV were blocked after SIRT1 was knocked down. These findings demonstrated that RSV upregulated the expression of SIRT1, restored lysosomal function, enhanced Ox-LDL-induced impaired autophagic flux, and promoted Ox-LDL degradation through the autophagy-lysosome degradation pathway in HUVECs.

Synthesis of Stilbene Derivatives: A Comparative Study of their Antioxidant Activities

A series of structurally simple compounds belonging to thestilbene family were synthesized by means of a Ti(III)-mediated methodology that allows access, in an efficient manner, to derivatives of dihydrostilbene, E-stilbene, and stilbene oxide, with high yields. The antioxidant activity of these compounds has been evaluated by means of two electrochemical assays, which provide complementary information, showing that the majority of these stilbene analogs exhibit significant antioxidant activity dependent on the electronic structure and functionalization of the molecule in each case.

A TagSNP in SIRT1 gene confers susceptibility to myocardial infarction in a Chinese Han population

SIRT1 exerts protective effects against endothelial cells dysfunction, inflammation and atherosclerosis, indicating an important role on myocardial infarction (MI) pathogenesis. Nonetheless, the effects of SIRT1 variants on MI risk remain poorly understood. Here we aimed to investigate the influence of SIRT1 polymorphisms on individual susceptibility to MI. Genotyping of three tagSNPs (rs7069102, rs3818292 and rs4746720) in SIRT1 gene was performed in a Chinese Han population, consisting of 287 MI cases and 654 control subjects. In a logistic regression analysis, we found that G allele of rs7069102 had increased MI risk with odds ratio (OR) of 1.57 [95% confidence interval (CI) = 1.15-2.16, Bonferroni corrected P (Pc) = 0.015] after adjustment for conventional risk factors compared to C allele. Similarly, the combined CG/GG genotypes was associated with the increased MI risk (OR = 1.64, 95% CI = 1.14-2.35, Pc = 0.021) compared to the CC genotype. Further stratified analysis revealed a more significant association with MI risk among younger subjects (≤ 55 years old). Consistent with these results, the haplotype rs7069102G-rs3818292A-rs4746720T containing the rs7069102 G allele was also associated with the increased MI risk (OR = 1.41, 95% CI = 1.09-1.84, Pc = 0.040). However, we did not detect any association of rs3818292 and rs4746720 with MI risk. Our study provides the first evidence that the tagSNP rs7069102 and haplotype rs7069102G-rs3818292A-rs4746720T in SIRT1 gene confer susceptibility to MI in the Chinese Han population.

Resveratrol post-transcriptionally regulates pro-inflammatory gene expression via regulation of KSRP RNA binding activity

Resveratrol shows beneficial effects in inflammation-based diseases like cancer, cardiovascular and chronic inflammatory diseases. Therefore, the molecular mechanisms of the anti-inflammatory resveratrol effects deserve more attention. In human epithelial DLD-1 and monocytic Mono Mac 6 cells resveratrol decreased the expression of iNOS, IL-8 and TNF-α by reducing mRNA stability without inhibition of the promoter activity. Shown by pharmacological and siRNA-mediated inhibition, the observed effects are SIRT1-independent. Target-fishing and drug responsive target stability experiments showed selective binding of resveratrol to the RNA-binding protein KSRP, a central post-transcriptional regulator of pro-inflammatory gene expression. Knockdown of KSRP expression prevented resveratrol-induced mRNA destabilization in human and murine cells. Resveratrol did not change KSRP expression, but immunoprecipitation experiments indicated that resveratrol reduces the p38 MAPK-related inhibitory KSRP threonine phosphorylation, without blocking p38 MAPK activation or activity. Mutation of the p38 MAPK target site in KSRP blocked the resveratrol effect on pro-inflammatory gene expression. In addition, resveratrol incubation enhanced KSRP-exosome interaction, which is important for mRNA degradation. Finally, resveratrol incubation enhanced its intra-cellular binding to the IL-8, iNOS and TNF-α mRNA. Therefore, modulation of KSRP mRNA binding activity and, thereby, enhancement of mRNA degradation seems to be the common denominator of many anti-inflammatory effects of resveratrol.

Impact of trans-resveratrol-sulfates and -glucuronides on endothelial nitric oxide synthase activity, nitric oxide release and intracellular reactive oxygen species

Resveratrol (3,5,4'-trihydroxy-trans-stilbene) is a polyphenolic natural product mainly present in grape skin, berries and peanuts. In the vasculature resveratrol is thought to boost endothelial function by increasing endothelial nitric oxide synthase (eNOS) expression, by enhancing eNOS activity, and by reduction of reactive oxygen species (ROS) levels. Recent studies show that dietary resveratrol is metabolized in the liver and intestine into resveratrol-sulfate and -glucuronide derivatives questioning the relevance of multiple reported mechanistic in vitro data on resveratrol. In this study, we compare side by side different physiologically relevant resveratrol metabolites (resveratrol sulfates- and -glucuronides) and their parent compound in their influence on eNOS enzyme activity, endothelial NO release, and intracellular ROS levels. In contrast to resveratrol, none of the tested resveratrol metabolites elevated eNOS enzyme activity and endothelial NO release or affected intracellular ROS levels, leaving the possibility that not tested metabolites are active and able to explain in vivo findings.

Resveratrol increases nitric oxide production in the rat thick ascending limb via Ca2+/calmodulin

The thick ascending limb of the loop of Henle reabsorbs 30% of the NaCl filtered through the glomerulus. Nitric oxide (NO) produced by NO synthase 3 (NOS3) inhibits NaCl absorption by this segment. Resveratrol, a polyphenol, has beneficial cardiovascular and renal effects, many of which are mediated by NO. Resveratrol increases intracellular Ca²⁺ (Ca_i) and AMP kinase (AMPK) and NAD-dependent deacetylase sirtuin1 (SIRT1) activities, all of which could activate NO production. We hypothesized that resveratrol stimulates NO production by thick ascending limbs via a Ca²⁺/calmodulin-dependent mechanism. To test this, the effect of resveratrol on NO bioavailability was measured in thick ascending limb suspensions. Ca_i was measured in single perfused thick ascending limbs. SIRT1 activity and expression were measured in thick ascending limb lysates. Resveratrol (100 µM) increased NO bioavailability in thick ascending limb suspensions by 1.3±0.2 AFU/mg/min (p<0.03). The NOS inhibitor L-NAME blunted resveratrol-stimulated NO bioavailability by 96±11% (p<0.03). The superoxide scavenger tempol had no effect. Resveratrol elevated Ca_i from 48±7 to 135±24 nM (p<0.01) in single tubules. In Ca²⁺-free media, the resveratrol-induced increase in NO was blunted by 60±20% (p<0.05) and the rise in Ca_i reduced by 80%. Calmodulin inhibition prevented the resveratrol-induced increase in NO (p<0.002). AMPK inhibition had no effect. Resveratrol did not increase SIRT1 activity. We conclude that resveratrol increases NO production in thick ascending limbs via a Ca²⁺/calmodulin dependent mechanism, and SIRT1 and AMPK do not participate. Resveratrol-stimulated NO production in thick ascending limbs may account for part of its beneficial effects.

SIRT1 in cardiovascular aging

Cardiovascular disease (CVD) is the leading cause of death worldwide, with aging as the key independent risk factor. Effective interventions are necessary to delay aging. Sirtuin1 (SIRT1), a NAD(+)-dependent histone deacetylase, is closely related to lifespan extension. SIRT1 exerts beneficial effects on aging and age-related diseases, such as atherosclerosis. In this review, we summarize the current knowledge on the functions of SIRT1 in cardiovascular aging, focusing on the underlying molecular mechanisms, including inhibition of oxidative stress and inflammation, and induction of autophagy. We also demonstrate that moderate up-regulation or activation of SIRT1 in cardiovascular aging and age-related CVD may confer important application values.

Resveratrol ameliorates low shear stress‑induced oxidative stress by suppressing ERK/eNOS‑Thr495 in endothelial cells

Fluid shear stress has been revealed to differentially regulate endothelial nitric oxide synthase (eNOS) distribution in vessels. eNOS, a key enzyme in controlling nitric oxide (NO) release, has a crucial role in mediating oxidative stress, and resveratrol (RSV)‑mediated eNOS also attenuates oxidative damage and suppresses endothelial dysfunction. To observe the protective effect of RSV on low shear stress (LSS)‑induced oxidative damage and the potential mechanisms involved, a parallel‑plate flow chamber, which imposed a low level of stress of 2 dynes/cm2 to cells, was employed. Reactive oxygen species (ROS), NO and apoptotic cells were examined in LSS‑treated endothelial cells (ECs) with or without RSV. Western blot analysis was used to examine LSS‑regulated eNOS‑Ser1177, Thr495 and Ser633, which were tightly associated with NO release. To further determine the underlying signaling pathways involved, extracellular signal‑regulated kinase (ERK), a possible upstream target of eNOS‑Thr495, was investigated, followed by examination of eNOS‑Thr495 in ERK‑inhibited cells. Additionally, eNOS mRNA expression levels were analyzed in cells challenged with LSS. The results revealed that RSV markedly decreased LSS‑induced oxidative damage in ECs. Furthermore, eNOS‑Ser1177 and Thr495 as well as phospho‑ERK were time‑dependently activated by LSS. The ERK inhibitor deactivated eNOS‑Thr495, which was accompanied by increased intracellular superoxide dismutase (SOD) levels. Of note, the activation effect of LSS on ERK/eNOS was markedly eliminated by RSV. In conclusion, RSV exerts antioxidant effects by suppressing LSS-activated ERK/eNOS and may provide a potential therapeutic target for atherosclerosis.

Linking the beneficial effects of current therapeutic approaches in diabetes to the vascular endothelin system

The rising epidemic of diabetes worldwide is of significant concern. Although the ultimate objective is to prevent the development and find a cure for the disease, prevention and treatment of diabetic complications is very important. Vascular complications in diabetes, or diabetic vasculopathy, include macro- and microvascular dysfunction and represent the principal cause of morbidity and mortality in diabetic patients. Endothelial dysfunction plays a pivotal role in the development and progression of diabetic vasculopathy. Endothelin-1 (ET-1), an endothelial cell-derived peptide, is a potent vasoconstrictor with mitogenic, pro-oxidative and pro-inflammatory properties that are particularly relevant to the pathophysiology of diabetic vasculopathy. Overproduction of ET-1 is reported in patients and animal models of diabetes and the functional effects of ET-1 and its receptors are also greatly altered in diabetic conditions. The current therapeutic approaches in diabetes include glucose lowering, sensitization to insulin, reduction of fatty acids and vasculoprotective therapies. However, whether and how these therapeutic approaches affect the ET-1 system remain poorly understood. Accordingly, in the present review, we will focus on experimental and clinical evidence that indicates a role for ET-1 in diabetic vasculopathy and on the effects of current therapeutic approaches in diabetes on the vascular ET-1 system.

Role of sirtuins in ischemia-reperfusion injury

Ischemia-reperfusion injury (IRI) remains an unresolved and complicated situation in clinical practice, especially in the case of organ transplantation. Several factors contribute to its complexity; the depletion of energy during ischemia and the induction of oxidative stress during reperfusion initiate a cascade of pathways that lead to cell death and finally to severe organ injury. Recently, the sirtuin family of nicotinamide adenine dinucleotide-dependent deacetylases has gained increasing attention from researchers, due to their involvement in the modulation of a wide variety of cellular functions. There are seven mammalian sirtuins and, among them, the nuclear/cytoplasmic sirtuin 1 (SIRT1) and the mitochondrial sirtuin 3 (SIRT3) are ubiquitously expressed in many tissue types. Sirtuins are known to play major roles in protecting against cellular stress and in controlling metabolic pathways, which are key processes during IRI. In this review, we mainly focus on SIRT1 and SIRT3 and examine their role in modulating pathways against energy depletion during ischemia and their involvement in oxidative stress, apoptosis, microcirculatory stress and inflammation during reperfusion. We present evidence of the beneficial effects of sirtuins against IRI and emphasize the importance of developing new strategies by enhancing their action.

Resveratrol protects HUVECs from oxidized-LDL induced oxidative damage by autophagy upregulation via the AMPK/SIRT1 pathway

PURPOSE

Resveratrol could induce basal autophagy through the activation of sirtuin. In this study, we investigated the effect of resveratrol on oxidative injury of human umbilical endothelial vein cells (HUVECs) induced by oxidized low-density lipoprotein (ox-LDL) and the role of autophagy in this effect.

METHODS

HUVECs were exposed to 100 mg/L ox-LDL for 24 h to cause oxidative injury. The effect of different concentrations of resveratrol on oxidative damage in HUVECs treated with ox-LDL was evaluated by MTT assay and superoxide dismutase (SOD) activity test. The autophagic level in different groups was measured by the protein expression of microtubule-associated protein 1 light chain 3 (LC3) and sequestosome 1 (SQSTM1/P62). Autophagosomes were observed under electron microscope and fluorescence microscope (by MDC staining). The expression of silencing information regulator1 (Sirt1) and AMP activated protein kinaseα1 (AMPK) was investigated by Western blot. Autophagy inhibitor 3-methyladenine (3-MA) and Sirt1 inhibitor 6-Chloro-2,3,4,9-tetrahydro-1H-Carbazole-1-carboxamide (EX527) were used to confirm the role of autophagy in this effect of resveratrol and the pathway involved.

RESULTS

Resveratrol reversed the decreases in cell viability (72.9 ± 1.7 % of the control group) and SOD activity (14.37 ± 0.21 U/ml) caused by ox-LDL at 83.4 ± 1.4 % of the control group and 16.41 ± 0.27 U/ml respectively. This effect accompanied by upregulation of autophagy and increased protein expression of Sirt1 and AMPK phosphorylation on threonine 172 (p-AMPK). Both 3-MA and EX527 abolished the protective effect of resveratrol in cell viability, at 80.4 ± 2.7 % and 73.9 ± 1.1 % of the control group respectively. 3-MA inhibited autophagy activation without any change of Sirt1 expression at both the mRNA and protein level. EX527 suppressed the expression of Sirt1 and diminished the upregulation of autophagy. Addition of 3-MA or EX527 could not affect the protein level of p-AMPK.

CONCLUSION

Resveratrol protected HUVECs from oxidative damage caused by ox-LDL. This effect was mediated by Sirt1-dependent autophagy via the AMPK/ Sirt1 pathway.

Resveratrol, from experimental data to nutritional evidence: the emergence of a new food ingredient

The polyphenol resveratrol is found notably in grapes and in a variety of medicinal plants. Recently, resveratrol has been suggested to have cardioprotective effects and to improve metabolic health by mimicking the effects of calorie restriction. Numerous animal and in vitro studies suggest that resveratrol could improve cardiovascular and metabolic health in humans. In view of this compelling preclinical evidence, several human studies investigating the effects of resveratrol on vascular and metabolic health have been initiated. Collectively, the animal, human epidemiological, and first human intervention studies support a role of resveratrol in vascular and metabolic health. This has led to the introduction of the first supplement and food products containing resveratrol and its emergence as a promising new health ingredient. Thus, supplementation with resveratrol may be included in nutritional and lifestyle programs aiming to reduce the risk of vascular and obesity-related problems.

Resveratrol and grape juice differentially ameliorate cardiovascular autonomic modulation in L-NAME-treated rats

Polyphenols consumption detected in red wine and grape juice may prevent or help in the treatment of hypertension. However, cardiovascular autonomic effects of polyphenols were poorly studied. Therefore, we evaluated the effects of resveratrol and grape juice treatments in hemodynamics, baroreflex sensitivity, heart rate (HR) and blood pressure (BP) variability and cardiac redox parameters. Male Wistar rats were divided in 3 groups (n=7/each) and treated for 30 days: only L-NAME-treated (60 mg/kg/day by oral gavage), L-NAME+resveratrol (L-NAME+R) and L-NAME+grape juice (L-NAME+G). BP signal was directly recorded and pulse interval (PI) and systolic arterial pressure (SAP) variability were analyzed in time and frequency domains. Baroreflex sensitivity (BRS) was determined by the alpha index. Oxidized and reduced glutathione concentrations were determined in cardiac tissue. L-NAME increased BP with no differences among groups (mean BP: L-NAME=124±4, L-NAME+R=126±3 and L-NAME+G=125±4 mmHg). PI and SAP variability expressed by total variance were also similar among groups. However, normalized low frequency (LF) and high frequency (HF) components of PI variability were lower and higher, respectively, in both R and G-treated groups when compared to only L-NAME group. Interestingly, sympathetic modulation to the vessels (LF from SAP variability) and BRS were decreased and increased, respectively, only in L-NAME+R rats. Additionally, GSH/GSSG ratios were higher in L-NAME+R and L-NAME+G than in L-NAME group. Our results indicate that resveratrol and grape juice treatments can modulate autonomic function and promote cardiac redox benefits even when nitric oxide is decreased. Moreover, resveratrol influences not only cardiac but also vascular autonomic modulation.

Protective Effects of Resveratrol on TNF-α-Induced Endothelial Cytotoxicity in Baboon Femoral Arterial Endothelial Cells

Endothelial injury induced by inflammatory factors plays a critical role in the pathogenesis of cardiovascular disease. Endothelial cell (EC) apoptosis, proliferation, migration, and cellular adhesion molecule (CAM) expression contribute to the development of atherosclerosis. We investigated the effects of resveratrol (0.1-100  μ M) on the proliferation, migration, and CAM expression of primary cultures of baboon arterial endothelial cells (BAECs). In addition, we tested its effects under normal conditions as well as under inflammatory conditions induced by tumour necrosis factor-α (TNF-α) administered either by cotreatment, pretreatment, or posttreatment. Immunocytochemistry, MTT, wound-healing, and flow cytometry assays were performed. The resveratrol treatment significantly enhanced BAEC proliferation and attenuated TNF-α-induced impairment of proliferation at the optimal doses of 1-50 µM. Resveratrol at a high dose (100  μ M) and TNF-α impaired BAEC migration, while low doses of resveratrol (1-50  μ M) attenuated TNF-α-induced impairment of BAEC migration. Moreover, resveratrol inhibited TNF-α-induced ICAM-1 and VCAM-1 expression. Taken together, our results suggest that the resveratrol protects BAECs after inflammatory stimulation as well as ameliorates inflammatory effects at low concentrations. Consequently, resveratrol should be considered as a candidate drug for the prevention and treatment of inflammatory vascular diseases.

Protection against recurrent stroke with resveratrol: endothelial protection

Despite increased risk of a recurrent stroke following a minor stroke, information is minimal regarding the interaction between injurious mild cerebral ischemic episodes and the possible treatments which might be effective. The aim of the current study was to investigate recurrent ischemic stroke and whether resveratrol, a nutritive polyphenol with promising cardio- and neuro- protective properties, could ameliorate the associated brain damage. Experiments in adult rats demonstrated that a mild ischemic stroke followed by a second mild cerebral ischemia exacerbated brain damage, and, daily oral resveratrol treatment after the first ischemic insult reduced ischemic cell death with the recurrent insult (P<0.002). Further investigation demonstrated reduction of both inflammatory changes and markers of oxidative stress in resveratrol treated animals. The protection observed with resveratrol treatment could not be explained by systemic effects of resveratrol treatment including effects either on blood pressure or body temperature measured telemetrically. Investigation of resveratrol effects on the blood-brain barrier in vivo demonstrated that resveratrol treatment reduced blood-brain barrier disruption and edema following recurrent stroke without affecting regional cerebral blood flow. Investigation of the mechanism in primary cell culture studies demonstrated that resveratrol treatment significantly protected endothelial cells against an in vitro ‘ischemia’ resulting in improved viability against oxygen and glucose deprivation (39.6±6.6% and 81.3±9.5% in vehicle and resveratrol treated cells, respectively). An inhibition of nitric oxide synthesis did not prevent the improved cell viability following oxygen glucose deprivation but SIRT-1 inhibition with sirtinol partially blocked the protection (P<0.001) suggesting endothelial protection is to some extent SIRT-1 dependent. Collectively, the results support that oral resveratrol treatment provides a low risk strategy to protect the brain from enhanced damage produced by recurrent stroke which is mediated in part by a protective effect of resveratrol on the endothelium of the cerebrovasculature.

Differential modulation of nitric oxide synthases in aging: therapeutic opportunities

Vascular aging is the term that describes the structural and functional disturbances of the vasculature with advancing aging. The molecular mechanisms of aging-associated endothelial dysfunction are complex, but reduced nitric oxide (NO) bioavailability and altered vascular expression and activity of NO synthase (NOS) enzymes have been implicated as major players. Impaired vascular relaxation in aging has been attributed to reduced endothelial NOS (eNOS)-derived NO, while increased inducible NOS (iNOS) expression seems to account for nitrosative stress and disrupted vascular homeostasis. Although eNOS is considered the main source of NO in the vascular endothelium, neuronal NOS (nNOS) also contributes to endothelial cells-derived NO, a mechanism that is reduced in aging. Pharmacological modulation of NO generation and expression/activity of NOS isoforms may represent a therapeutic alternative to prevent the progression of cardiovascular diseases. Accordingly, this review will focus on drugs that modulate NO bioavailability, such as nitrite anions and NO-releasing non-steroidal anti-inflammatory drugs, hormones (dehydroepiandrosterone and estrogen), statins, resveratrol, and folic acid, since they may be useful to treat/to prevent aging-associated vascular dysfunction. The impact of these therapies on life quality in elderly and longevity will be discussed.

Penetration of resveratrol into bovine aortic endothelial cells (BAEC): a possible passive diffusion

Several studies have demonstrated that, in a context of oxidative stress, resveratrol, a polyphenol found in wine, could act as a protective agent on endothelial cells by various mechanisms but without showing that it could penetrate inside the cell. The aim of this study was to detect for the first time resveratrol inside bovine endothelial aortic cells and to determine which kind of transport mechanism was involved. Intracellular and membrane concentrations of resveratrol have been measured by high performance liquid chromatography after incubation of several concentrations of resveratrol with endothelial cells for 24h. Concentrations of resveratrol in the culture media have been determined by UV spectrophotometry and experiments of transport mechanisms have been performed. Our results showed that, for the concentrations tested (1, 5, 10 and 50 μM), resveratrol was detected inside the cells and suggested that it was able to penetrate into the cells through a passive diffusion mechanism.

XJP-1, a novel ACEI, with anti-inflammatory properties in HUVECs

AIM

We investigated whether 8-dihydroxy-3-methyl-isochromanone (XJP-1), a novel angiotensin-converting enzyme inhibitor (ACEI), exhibited inhibitory activity to lipopolysaccharide (LPS)-accelerated vascular inflammation.

METHODS

Human umbilical vein endothelial cells (HUVECs) were isolated from human umbilical cords and cultured. The direct effect of XJP-1 on the activation of endothelial cells was measured using MTT assay. Nitric oxide (NO) in the culture medium was measured using Griess method. The expression of cell adhesion molecules (ICAM-1 and VCAM-1) was determined by flow cytometry and RT-PCR. The protein expression levels of tumor necrosis factor-α (TNF-α), monocyte chemotactic protein (MCP)-1, and endothelin-1 (ET-1) secretion were measured using ELISA. Quantitative analysis of eNOS, iNOS, inhibitory factor NF-κB (IκB) and MAPKs were determined using Western blot analysis. The translocation of NF-κB from the cytoplasm to the nucleus was determined using immunofluorescence.

RESULTS

XJP-1 significantly inhibited LPS-mediated endothelial cell dysfunction, as measured by NO production, iNOS expression, adhesion molecule (ICAM-1, VCAM-1) expression, and chemokine (TNF-α, MCP-1) production in vitro. It up-regulated eNOS expression in the same experimental setting. XJP-1 alone was found non-cytotoxic at the concentration up to 1000μM. The mechanistic investigations of XJP-1 suppression LPS-induced inflammation in HUVECs revealed that XJP-1 blocked NF-κB nuclear entry in an IκB-dependent manner, as well as inhibited MAPK activation induced by LPS. XJP-1 reduced endothelin-1 secretion and increased nitric oxide metabolite production by HUVECs. However, the effect of XJP-1 on nitric oxide and endothelin-1 metabolite production is mediated by the activation of bradykinin B(2) receptor being counteracted, at least in part, by a specific antagonist.

CONCLUSION

XJP-1 inhibited LPS-induced cytotoxicity and inflammatory response. The mechanism underlying this protective effect might be related to the inhibition of MAPK and NF-κB signaling pathway activation, suggesting the potential inhibition of the atherosclerotic process by suppressing the expression of chemoattractant molecules and monocyte adhesion. XJP-1 also has an effect in improving endothelin-1 through activating bradykinin B(2) receptor. These findings indicated that XJP-1 is potentially a novel therapeutic candidate for the treatment of atherosclerosis.

Trans-resveratrol simultaneously increases cytoplasmic Ca(2+) levels and nitric oxide release in human endothelial cells

SCOPE

The aim of this study was to investigate whether the dietary polyphenol trans-resveratrol (t-Resv) increases [Ca(2+)](c) in endothelial cells, leading to a simultaneous augmentation of nitric oxide (NO) biosynthesis.

METHODS AND RESULTS

We have separately and simultaneously measured [Ca(2+)](c) and NO in human endothelial cells using the Ca(2+) indicator fura-2 and the NO-sensitive fluorescent probe 4,5-diaminofluorescein. In ∼30% of cells, t-Resv (30 μM) induced an increase in [Ca(2+)](c) with a transient as well as sustained component and a simultaneous increase in NO biosynthesis. This effect was reduced by non-selective Ca(2+) channel blockers, inhibition of intracellular Ca(2+) release, inhibition of endothelial nitric oxide synthase (eNOS) and, to a lesser extent, inhibition of extracellular signal-regulated kinase 1/2 (ERK 1/2) or 5' adenosine monophosphate-activated protein kinase (AMPK). t-Resv did not modify in vitro eNOS activity, suggesting that the observed stimulation of NO generation proceeds via mobilisation of Ca(2+) and not through direct effects on eNOS.

CONCLUSION

We therefore show, for the first time, that t-Resv induces a concentration-dependent, simultaneous increase in [Ca(2+)](c) and NO biosynthesis that could be linked to its endothelium-dependent vasorelaxant effect. Under the assumption that t-Resv exhibits similar behaviour in human blood vessels in vivo, the pharmacological properties described here may contribute to the beneficial cardiovascular effects of this polyphenol by improving endothelial function.

Endothelins and their receptors in cancer: identification of therapeutic targets

Endothelins and their receptors are important in normal physiology, but have been implicated in various pathophysiological conditions. Members of the so-called "endothelin axis" are dysregulated in a wide range of human cancers, opening the door for novel anticancer therapies. Established cancer chemotherapeutic agents and drugs that target specific components of the endothelin axis have been combined with promising results, but more work is needed in this area. The endothelin axis affects numerous signaling pathways, including Ras, mitogen activated protein kinases, β-catenin/T-cell factor/lymphoid enhancer factor, nuclear factor-κB (NFκB), SNAIL, and mammalian target of rapamycin (mTOR). There is much still to learn about optimizing drug specificity in this area, while minimizing off-target effects. Selective agonists and antagonists of endothelins, their receptors, and upstream processing enzymes, as well as knockdown strategies in vitro, are providing valuable leads for testing in the clinical setting. The endothelin axis continues to be an attractive avenue of scientific endeavor, both in the cancer arena and in other important health-related disciplines.