Prehypertensives exhibit marked endothelial dysfunction, a risk factor for future cardiovascular morbidity and mortality. However, the ability of exercise to ameliorate endothelial dysfunction in prehypertensives is grossly underinvestigated. This prospective randomized and controlled study examined the separate effects of resistance and endurance training on conduit artery endothelial function in young prehypertensives. Forty-three unmedicated prehypertensive (systolic blood pressure [SBP]=120-139 mmHg; diastolic blood pressure [DBP]=80-89 mmHg) but otherwise healthy men and women and 15 normotensive matched time-controls (NMTC); n = 15) between 18 and 35 y of age met screening requirements and participated in the study. Prehypertensive subjects were randomly assigned to either a resistance exercise training (PHRT; n = 15), endurance exercise training (PHET; n = 13) or time-control group (PHTC; n = 15). The treatment groups performed exercise training three days per week for eight weeks. The control groups did not initiate exercise programs throughout the study. Flow mediated dilation (FMD) of the brachial artery, biomarkers of enodothelial function and peripheral blood pressure were evaluated before and after exercise intervention or time-matched control. PHRT and PHET reduced resting SBP (9.6± 3.6 and 11.9 ± 3.4 mmHg, respectively; P<0.05) and DBP (8.0± 5.1 and 7.2 ± 3.4 mmHg, respectively; P<0.05). Exercise training improved brachial artery FMD absolute diameter, percent dilation and normalized percent dilation by 30%, 34% and 19% for PHRT, P<0.05; and by 54%, 63% and 75% for PHET, P<0.05; respectively. PHRT and PHET increased plasma concentrations of 6-keto prostaglandin F1α (19% and 22%, respectively; P<0.05), NO x (19% and 23%, respectively; P<0.05), and reduced endothelin-1 by (16% and 24%, respectively; P<0.01). This study provides novel evidence that resistance and endurance exercise separately have beneficial effects on resting peripheral blood pressure, brachial artery FMD and endothelial-derived vasoactive agents in young prehypertensives.

Prehypertensives exhibit marked endothelial dysfunction, a risk factor for future cardiovascular morbidity and mortality. However, the ability of exercise to ameliorate endothelial dysfunction in prehypertensives is grossly underinvestigated. This prospective randomized and controlled study examined the separate effects of resistance and endurance training on conduit artery endothelial function in young prehypertensives. Forty-three unmedicated prehypertensive (systolic blood pressure [SBP]=120-139 mmHg; diastolic blood pressure [DBP]=80-89 mmHg) but otherwise healthy men and women and 15 normotensive matched time-controls (NMTC); n = 15) between 18 and 35 y of age met screening requirements and participated in the study. Prehypertensive subjects were randomly assigned to either a resistance exercise training (PHRT; n = 15), endurance exercise training (PHET; n = 13) or time-control group (PHTC; n = 15). The treatment groups performed exercise training three days per week for eight weeks. The control groups did not initiate exercise programs throughout the study. Flow mediated dilation (FMD) of the brachial artery, biomarkers of enodothelial function and peripheral blood pressure were evaluated before and after exercise intervention or time-matched control. PHRT and PHET reduced resting SBP (9.6± 3.6 and 11.9 ± 3.4 mmHg, respectively; P<0.05) and DBP (8.0± 5.1 and 7.2 ± 3.4 mmHg, respectively; P<0.05). Exercise training improved brachial artery FMD absolute diameter, percent dilation and normalized percent dilation by 30%, 34% and 19% for PHRT, P<0.05; and by 54%, 63% and 75% for PHET, P<0.05; respectively. PHRT and PHET increased plasma concentrations of 6-keto prostaglandin F1α (19% and 22%, respectively; P<0.05), NO x (19% and 23%, respectively; P<0.05), and reduced endothelin-1 by (16% and 24%, respectively; P<0.01). This study provides novel evidence that resistance and endurance exercise separately have beneficial effects on resting peripheral blood pressure, brachial artery FMD and endothelial-derived vasoactive agents in young prehypertensives.

The impact of exercise training on vascular health in adolescents with type 2 diabetes has not been previously studied. We hypothesized that exercise training would improve micro- and macrovascular health in adolescents with type 2 diabetes. Thirteen adolescents (13-21 years, 10F) with type 2 diabetes were recruited from Princess Margaret Hospital. Participants were randomized to receive either an exercise program along with standard clinical care (n = 8) or standard care alone (n = 5). Those in the intervention group received 12 weeks of gym-based, personalized, and supervised exercise training. Those in the control group were instructed to maintain usual activity levels. Assessments were conducted at baseline and following week 12. The exercise group was also studied 12 weeks following the conclusion of their program. Assessments consisted of conduit artery endothelial function (flow-mediated dilation, FMD) and microvascular function (cutaneous laser Doppler). Secondary outcomes included body composition (dual-energy X-ray absorptiometry, DXA), glycemic control (whole body insulin sensitivity, M) assessed using the euglycemic-hyperinsulinemicclamp protocol, cardiorespiratory fitness (V˙O2peak), and muscular strength (1RM). Exercise training increased FMD (P < 0.05), microvascular function (P < 0.05), total lean mass (P < 0.05), and muscle strength (P < 0.001). There were no changes in cardiorespiratory fitness, body weight, BMI, or M. In the control group, body weight (P < 0.01), BMI (P < 0.01), and total fat mass (P < 0.05) increased. At week 24, improvements in vascular function were reversed. This study indicates that exercise training can improve both conduit and microvascular endothelial function and health, independent of changes in insulin sensitivity in adolescents with type 2 diabetes.

Highly active antiretroviral therapy (HAART) has significantly improved the prognosis of HIV-1-infected patients but is associated with significant side effects such as diabetes, atherosclerosis, and cardiovascular complications. Oxidative stress can disrupt endothelial homeostasis by dysregulating the balance between pro- and antiatherogenic factors. We hypothesized that chronic exposure to HAART results in endothelial oxidative stress and activation of mononuclear cell recruitment, an early event in atherosclerosis. We studied the effects of HAART drug combinations, consisting of zidovudine, a nucleoside reverse transcriptase inhibitor; efavirenz, a nonnucleoside reverse transcriptase inhibitor; and either of the two protease inhibitors (PIs), indinavir or nelfinavir, on human aortic endothelial cells (HAECs) by monitoring the following parameters: (1) generation of reactive oxygen species (ROS), (2) mono-nuclear cell (Jurkat or U-937) adhesion, and (3) expression of cell adhesion molecules (CAMs). HAART exposure increased ROS formation in HAECs. Exposure to PIs alone and in HAART combinations increased mononuclear cell adhesion to HAECs in a concentration-dependent manner. Mononuclear cell adhesion to HAART-exposed HAECs was significantly enhanced following acute (24-h) exposure to the inflammatory cytokines, tumor necrosis factor (TNF)-alpha or interleukin (IL)-1beta and was suppressed by the antioxidants N-ace-tylcysteine and glutathione. Exposure to HAART increased intercellular adhesion molecule-1 (ICAM-1) gene expression and concomitant exposure to TNF-alpha further increased ICAM-1, vascular cell adhesion molecule-1 (VCAM-1), and endothelial-leukocyte adhesion molecule cell surface protein levels. These studies indicate that chronic HAART exposure increases oxidative stress in endothelial cells and induces mononuclear cell recruitment, which may eventually precipitate the cardiovascular diseases observed in HIV-1+ individuals on antiretroviral therapy.

The study aims to investigate the effect of spa treatment on vascular endothelium and clinical symptoms of generalized osteoarthritis. Forty generalized osteoarthritis (GOA) patients referred to a government spa hospital, and 40 GOA patients followed on university hospital locomotor system disease ambulatory clinics were included as study and control groups, respectively. Study group received spa treatment including thermal water baths, physical therapy modalities, and exercises. Control group was followed with home exercises for 15 days. Plasma ADMA, L-arginine, L-arginine/ADMA ratio, routine blood analyses, 6-min walking test, including fingertip Osaturation, systolic/diastolic blood pressure, and pulse rate, were measured at the beginning and at the end of treatment. Groups were evaluated with VAS pain, patient, and physician global assessment; HAQ; and WOMAC at the beginning, at the end, and after 1 month of treatment. In study group, L-arginine and L-arginine/ADMA ratio showed statistically significant increase after treatment. PlasmaADMA levels did not change. There is no significant difference in intergroup comparison. Study group displayed statistically significant improvements in all clinical parameters. The study showed that spa treatment does not cause any harm to the vascular endothelium through ADMA. Significant increasein plasma L-arginine and L-arginine/ADMA ratio suggests that balneotherapy may play a preventive role on cardiovascular diseases. Balneotherapy provides meaningful improvements on clinical parameters of GOA.

BACKGROUND:Loss of endothelium-derived nitric oxide (EDNO) contributes to the clinical expression of coronary artery disease (CAD). Increased oxidative stress has been linked to impaired endothelial vasomotor function in atherosclerosis, and recent studies demonstrated that short-term ascorbic acid treatment improves endothelial function.

METHODS AND RESULTS:In a randomized, double-blind, placebo-controlled study, we examined the effects of single-dose (2 g PO) and long-term (500 mg/d) ascorbic acid treatment on EDNO-dependent flow-mediated dilation of the brachial artery in patients with angiographically established CAD. Flow-mediated dilation was examined by high-resolution vascular ultrasound at baseline, 2 hours after the single dose, and 30 days after long-term treatment in 46 patients with CAD. Flow-mediated dilation improved from 6.6+/-3.5% to 10.1+/-5.2% after single-dose treatment, and the effect was sustained after long-term treatment (9. 0+/-3.7%), whereas flow-mediated dilation was 8.6+/-4.7% at baseline and remained unchanged after single-dose (7.8+/-4.4%) and long-term (7.9+/-4.5%) treatment with placebo (P=0.005 by repeated-measures ANOVA). Plasma ascorbic acid concentrations increased from 41.4+/-12. 9 to 115.9+/-34.2 micromol/L after single-dose treatment and to 95. 0+/-36.1 micromol/L after long-term treatment (P<0.001).

CONCLUSIONS:In patients with CAD, long-term ascorbic acid treatment has a sustained beneficial effect on EDNO action. Because endothelial dysfunction may contribute to the pathogenesis of cardiovascular events, this study indicates that ascorbic acid treatment may benefit patients with CAD.

The Mediterranean Diet, characterized by higher intakes of plant foods including plant proteins, monounsaturated fat, fish, and lower consumption of animal products and saturated fat, has long been associated with reduced cardiovascular risk, but the molecular mechanisms underlying these associations have not been fully elucidated. We conducted a pilot study to evaluate associations of an Alternate Mediterranean Diet Score, reflective of adherence to this diet pattern and adapted for US populations, and its components, with markers of endothelial inflammation directly measured in endothelial cells harvested from a diverse sample of women (n = 25, mean ± SD age 33 ± 10.5y, 68% racial/ethnic minorities). Cardiovascular risk markers including nuclear factor kappa B (NF-κB)-a marker of inflammation, as well as oxidative stress and endothelial nitric oxide synthase (eNOS) gene expression-markers of endothelial function, wereevaluated in harvested endothelial cells. We hypothesized that the Mediterranean diet pattern would be associated with lower inflammation and oxidative stress and higher eNOS expression in endothelial cells. Results showed that lower oxidative stress was associated with higher plant-based protein (Exp(β) = 0.96; P = .007), overall protein (Exp(β) = 0.99; P = .007), and red and processed meat intake (Exp(β) = 0.93; P = .012). Lower NF-κB was associated with higher legume (Exp(β) = 0.79; P = .045) intake, and higher eNOS was associated with higher red and processed meat intake (Exp(β) = 1.13; P = .005). Our findings suggest potential novel mechanisms through which certain Mediterranean dietary components may influence pre-clinical vascular alterations that may be associated with cardiovascular risk through lower endothelial oxidative stress, lower inflammation, and greater endothelial functioning. These findings warrant confirmation, prospectively in a larger sample.

BACKGROUND AND AIMS:Endothelial dysfunction (ED) plays a key role in the development of atherosclerotic cardiovascular disease (ASCVD). Likewise, type 2 diabetes (T2D) is a major CVD risk factor. Therefore, our objective was to explore whether long-term consumption of a Mediterranean diet (MedDiet) rich in olive oil or a low-fat diet (LF diet) was associated with an improvement in ED and whether the potential benefits were similar in patients with or without T2D in the CORDIOPREV clinical trial (NCT00924937).

METHODS:Endothelial function was measured in 805 participants who had completed follow-up ultrasound image studies, using ultrasonography of brachial artery to calculate flow mediated vasodilatation (FMD) before and after 1.5 years of intervention with a MedDiet [35% of calories from fat (22% monounsaturated) and 50% from carbohydrates] and LF diet [28% fat (12% monounsaturated) and 55% of calories from carbohydrates]. We categorized participants as patients with T2D, prediabetes, and without T2D according to the American Diabetes Association (ADA) criteria.

RESULTS:MedDiet increased FMD in patients with T2D [5.2 ± 0.4 at 1.5 years vs. 3.8 ± 0.4 at baseline; p=0.04] and prediabetes [4.9 ± 0.4 vs. 3.8 ± 0.4; p=0.04] and induced an improvement in FMD compared to LF diet in patients with diabetes [5.2 ± 0.4 (MedDiet) vs.3.7 ± 0.4 (LF diet); p=0.01]; whereas both diets maintained FMD stablein patients without diabetes.

CONCLUSIONS:Habitual consumption of a MedDiet rich in extra virgin olive oil improves endothelial function in patients with prediabetes and diabetes. This takes great importance given that diet must be the cornerstone of treatment of patients with diabetes at high cardiovascular risk.

BACKGROUND:Endothelial dysfunction is a fundamental step in the atherosclerotic disease process. Activation or injury of the endothelium leads to a variety of inflammatory disorders, including the release of microparticles. Endothelial progenitor cells may contribute to the maintenance of the endothelium by replacing injured mature endothelial cells.

OBJECTIVE:We studied the influence of dietary fat on the release of endothelial microparticles (EMPs) and endothelial progenitor cells (EPCs) in elderly subjects.

DESIGN:Twenty healthy, elderly subjects (10 men and 10 women) consumed 3 diets following a randomized crossover design, each for 4 wk: a saturated fatty acid diet; a low-fat, high-carbohydrate diet; and a Mediterranean diet (MedDiet) enriched in monounsaturated fatty acids. We investigated total microparticles, EMPs from activated endothelial cells (activated EMPs), EMPs from apoptotic endothelial cells (apoptotic EMPs), EPCs, oxidative stress variables, and ischemic reactive hyperemia (IRH).

RESULTS:The MedDiet led to lower total microparticle, activated EMP, and apoptotic EMP concentrations and higher EPC numbers than did the other diets (P<0.001). We detected lower superoxide dismutase activity (P<0.001), a higher plasmaβ-carotene concentration (P<0.001), and lower urinary isoprostane and plasma nitrotyrosine concentrations after consumption of the MedDiet than after consumption of the other 2 diets (P<0.05). Furthermore, the occurrence of IRH was higher after consumption of the MedDiet than after consumption of the other 2 diets (P<0.05).

CONCLUSION:Consumption of the MedDiet induces a reduction in endothelial damage and dysfunction, which is associated with an improvement in the regenerative capacity of the endothelium, in comparison with 2 other diets.

OBJECTIVE: To determine effects of oat and antioxidant vitamin (C 500 mg, E 400 IU) ingestion on endothelial function in overweight, dyslipidemic adults. DESIGN: Randomized, blinded, placebo-controlled, crossover trial Intervention(s): Subjects (16 males>or = age 35; 14 postmenopausal females) were assigned, in random order, to oats (60 g oatmeal), vitamin E (400 IU) plus vitamin C (500 mg), the combination of oats and vitamins, or placebo, and underwent brachial artery reactivity scans (BARS) following a single dose of each treatment, and again following 6 weeks of daily ingestion, with 2-week washout periods. At each test, a provocation high-fat meal (50 g, predominantly saturated) was administered and subjects were scanned pre, and 3 hours post-ingestion. RESULTS: Mean flow-mediated vasodilation (FMD; measured as percent diameter change before and after treatments) at baseline was 6.35 +/- 3.37. Oats increased FMD non-significantly (p>0.05) with both single acute dose (from 6.07 +/- 6.25 to 9.22 +/- 8.82) and six weeks of sustained treatment (from 6.01 +/- 10.07 to 8.69 +/- 8.42). The direction of effect was negative for vitamins and the oat/vitamin combination with both acute and sustained treatment. There were no significant differences in FMD change among the treatments in either phase of the study, however when acute and sustained effects were pooled, oat treatment significantly augmented FMD (p<0.05). CONCLUSIONS: This trial suggests but does not confirm a beneficial influence of oat ingestion on endothelial function in overweight, dyslipidemic adults. Further study of this potential association is warranted.

OBJECTIVE: Epidemiology suggests that Mediterranean diets are associated with reduced risk of cardiovascular disease. Because monocyte adhesion to the endothelium is crucial in early atherogenesis, we evaluated whether typical olive oil and red wine polyphenols affect endothelial-leukocyte adhesion molecule expression and monocyte adhesion.

METHODS AND RESULTS: Phytochemicals in olive oil and red wine, including oleuropein, hydroxytyrosol, tyrosol, elenolic acid, and resveratrol, with or without antioxidant activity, were incubated with human umbilical vein endothelial cells for 30 minutes, followed by co-incubation with bacterial lipopolysaccharide or cytokines to trigger adhesion molecule expression. At nutritionally relevant concentrations, only oleuropein, hydroxytyrosol, and resveratrol, possessing a marked antioxidant activity, reduced monocytoid cell adhesion to stimulated endothelium, as well as vascular cell adhesion molecule-1 (VCAM-1) mRNA and protein by Northern analysis and cell surface enzyme immunoassay. Reporter gene assays with deletional VCAM-1 promoter constructs indicated the relevance of nuclear factor-kappaB, activator protein-1, and possibly GATA binding sites in mediating VCAM-1 transcriptional inhibition. The involvement of nuclear factor-kappaB and activator protein-1 was finally demonstrated at electrophoretic mobility shift assays.

CONCLUSIONS: Olive oil and red wine antioxidant polyphenols at nutritionally relevant concentrations transcriptionally inhibit endothelial adhesion molecule expression, thus partially explaining atheroprotection from Mediterranean diets.

Regular aerobic exercise training improves endothelium-dependent arterial dilation in patients with impaired fasting glucose.

Postprandial hyperglycemia induces oxidative stress responses, impairs vascular endothelial function (VEF) and increases the risk of cardiovascular disease. We hypothesized that the antioxidant and anti-inflammatory activities of aγ-tocopherol-rich mixture of tocopherols (γ-TmT) would protect against vascular dysfunction that is otherwise caused by postprandial hyperglycemia by decreasing oxidative stress and proinflammatory responses, and improving nitric oxide (NO•) homeostasis. In a randomized, crossover study, healthymen (n=15; 21.8 ± 0.8 years) completed a fasting oral glucose challenge (75 g) with or without prior supplementation of γ-TmT (5 days). Brachial artery flow-mediated dilation (FMD), plasma glucose, insulin, antioxidants, malondialdehyde (MDA), inflammatory proteins, arginine and asymmetric dimethylarginine (ADMA) were measured at regular intervals during a 3-h postprandial period. Supplementation of γ-TmT increased (P<.05) plasmaγ-T by threefold and γ-carboxyethyl-hydroxychroman by more than ninefold without affecting α-T, glucose, arginine or ADMA. Baseline FMD, MDA, arginine and ADMA were unaffected by γ-TmT (P>.05). Postprandial FMD decreased 30%-44% (P<.05) following glucose ingestion, but was maintained withγ-TmT. Supplementation of γ-TmT also attenuated postprandial increases in MDA that occurred following glucose ingestion. Plasma arginine decreased (P<.05) in both trials to a similar extent regardless ofγ-TmT supplementation. However, the ratio of ADMA/arginine increased time-dependently in both trials (P<.05), but to a lesser extent followingγ-TmT supplementation (P<.05). Inflammatory proteins were unaffected by glucose ingestion orγ-TmT. Collectively, these findings support that short-term supplementation of γ-TmT maintains VEF during postprandial hyperglycemia possibly by attenuating lipid peroxidation and disruptions in NO• homeostasis, independent of inflammation.

OBJECTIVES: Our goal was to test feasibility and efficacy of a dietary intervention based on daily intake of flavanol-containing cocoa for improving vascular function of medicated diabetic patients. BACKGROUND: Even in fully medicated diabetic patients, overall prognosis is unfavorable due to deteriorated cardiovascular function. Based on epidemiological data, diets rich in flavanols are associated with a reduced cardiovascular risk. METHODS: In a feasibility study with 10 diabetic patients, we assessed vascular function as flow-mediated dilation (FMD) of the brachial artery, plasma levels of flavanol metabolites, and tolerability after an acute, single-dose ingestion of cocoa, containing increasing concentrations of flavanols (75, 371, and 963 mg). In a subsequent efficacy study, changes in vascular function in 41 medicated diabetic patients were assessed after a 30-day, thrice-daily dietary intervention with either flavanol-rich cocoa (321 mg flavanols per dose) or a nutrient-matched control (25 mg flavanols per dose). Both studies were undertaken in a randomized, double-masked fashion. Primary and secondary outcome measures included changes in FMD and plasma flavanol metabolites, respectively. RESULTS: A single ingestion of flavanol-containing cocoa was dose-dependently associated with significant acute increases in circulating flavanols and FMD (at 2 h: from 3.7 +/- 0.2% to 5.5 +/- 0.4%, p < 0.001). A 30-day, thrice-daily consumption of flavanol-containing cocoa increased baseline FMD by 30% (p < 0.0001), while acute increases of FMD upon ingestion of flavanol-containing cocoa continued to be manifest throughout the study. Treatment was well tolerated without evidence of tachyphylaxia. Endothelium-independent responses, blood pressure, heart rate, and glycemic control were unaffected. CONCLUSIONS: Diets rich in flavanols reverse vascular dysfunction in diabetes, highlighting therapeutic potentials in cardiovascular disease.

The concept of mild chronic vascular inflammation as part of the pathophysiology of cardiovascular disease, most importantly hypertension and atherosclerosis, has been well accepted. Indeed there are links between vascular inflammation, endothelial dysfunction and oxidative stress. However, there are still gaps in our understanding regarding this matter that might be the cause behind disappointing results of antioxidant therapy for cardiovascular risk factors in large-scale long-term randomised controlled trials. Apart from the limitations of our knowledge, limitations in methodology and assessment of the body's endogenous and exogenous oxidant-antioxidant status are a serious handicap. The pleiotropic effects of antioxidant and anti-inflammation that are shown by some well-established antihypertensive agents and statins partly support the idea of using antioxidants in vascular diseases as still relevant. This review aims to provide an overview of the links between oxidative stress, vascular inflammation, endothelial dysfunction and cardiovascular risk factors, importantly focusing on blood pressure regulation and atherosclerosis. In view of the potential benefits of antioxidants, this review will also examine the proposed role of vitamin C, vitamin E and polyphenols in cardiovascular diseases as well as the success or failure of antioxidant therapy for cardiovascular diseases in clinical trials.

BACKGROUND:This study assessed whether aerobic exercise would attenuate microvascular endothelial dysfunction induced by commercial sugar-sweetened beverage (SSB) consumption.

METHODS:Eleven healthy males participated in this randomized, single-blind crossover study. Cutaneous microvascular endothelial function was assessed using laser speckle contrast imaging coupled with post-occlusive reactive hyperemia before and after a) consumption of water; b) consumption of a commercial SSB; c) 30min of aerobic exercise followed by water consumption; and d) 30 minutes of aerobic exercise followed by SSB consumption. Blood glucose and arterial pressure responses were also monitored. Volumes of water and SSB consumed (637.39±29.15 mL) were individualized for each participant, ensuring SSB consumption delivered 1 g of sucrose per kg of body weight. Exercise was performed at 75% of the maximal oxygen uptake heart rate.

RESULTS:Compared to water consumption, the commercial SSB elevated blood glucose concentrations in both sedentary (4.69±0.11 vs. 7.47±0.28 mmol/L, P<0.05) and exercised states (4.95±0.13 vs. 7.93±0.15 mmol/L, P<0.05). However, the decrease in microvascular endothelial function observed following sedentary SSB consumption, expressed as the percentage increase from baseline (208.60±22.40 vs. 179.83±15.80%, P=0.01) and the change in peak hyperemic blood flux from basal to post-intervention assessments (-0.04±0.03 vs. -0.12±0.02 ΔCVC, P=0.01), was attenuated following 30min of aerobic exercise.

CONCLUSIONS:To our knowledge, this is the first study to provide evidence that a single bout of aerobic exercise may prevent transient SSB-mediated microvascular endothelial dysfunction.

AIMS:Investigate the effect of ascorbic acid (vitamin C) on the endothelial dysfunction induced by acute ethanol intake.

MAIN METHODS:Ethanol (1 g/kg; p.o. gavage) effects were assessed within 30 min in male Wistar rats.

KEY FINDINGS:Ethanol intake decreased the endothelium-dependent relaxation induced by acetylcholine in the rat aorta and treatment with vitamin C (250 mg/kg; p.o. gavage, 5 days) prevented this response. Ethanol increased superoxide anion (O2(-)) generation and decreased aortic nitrate/nitrite levels and these responses were not prevented by vitamin C. Superoxide dismutase (SOD) and catalase (CAT) activities as well as hydrogen peroxide (H2O2) and reduced glutathione (GSH) levels were not affected by ethanol. RhoA translocation as well as the phosphorylation levels of protein kinase B (Akt), eNOS (Ser(1177) or Thr(495) residues), p38MAPK, SAPK/JNK and ERK1/2 was not affected by ethanol intake. Vitamin C increased SOD activity and phosphorylation of Akt, eNOS (Ser(1177) residue) and p38MAPK in aortas from both control and ethanol-treated rats. Incubation of aortas with tempol prevented ethanol-induced decrease in the relaxation induced by acetylcholine. Ethanol (50 mM/1 min) increased O2(-) generation in cultured aortic vascular smooth muscle cells (VSMC) and vitamin C did not prevent this response. In endothelial cells, vitamin C prevented the increase on ROS generation and the decrease in the cytosolic NO content induced by ethanol.

SIGNIFICANCE:Our study provides novel evidence that vitamin C prevents the endothelial dysfunction induced by acute ethanol intake by a mechanism that involves reduced ROS generation and increased NO availability in endothelial cells.

Antioxidant vitamins C and E have protective properties in genetic hypertension associated with enhanced oxidative stress. This study investigated whether vitamins C and/or E modulate vascular function by regulating enzymatic activities of endothelial nitric oxide synthase (eNOS) and NAD(P)H oxidase using thoracic aortas of 20- to 22-week-old male spontaneously hypertensive rats (SHR) and their matched normotensive counterparts, Wistar-Kyoto rats (WKY). SHR aortas had impaired relaxant responses to acetylcholine but not to sodium nitroprusside, despite an approximately 2-fold increase in eNOS activity and NO release. The levels of superoxide anion (O2-), a potent NO scavenger, and NAD(P)H oxidase activity were also 2-fold higher in SHR aortas. Mechanical but not pharmacological inactivation of endothelium (by rubbing and 100 micromol/L L-NAME, respectively) significantly abrogated O2- in both strains. Treatments of SHR aortas with NAD(P)H oxidase inhibitors, namely diphenyleneiodinium and apocynin, significantly diminished O2- production. The incubation of SHR aortas with different concentrations of vitamin C (10 to 100 micromol/L) and specifically with high concentrations of vitamin E (100 micromol/L) improved endothelial function, reduced superoxide production as well as NAD(P)H oxidase activity, and increased eNOS activity and NO generation in SHR aortas to the levels observed in vitamin C- and E-treated WKY aortas. Our results reveal endothelial NAD(P)H oxidase as the major source of vascular O2- in SHR and also show that vitamins C and E are critical in normalizing genetic endothelial dysfunction through regulation of eNOS and NAD(P)H oxidase activities.