Vascular nitric oxide and oxidative stress: determinants of endothelial adaptations to cardiovascular disease and to physical activity

Lack of Intensity Control during an Exercise Program Is Related to a Limited Effect on Variables Responsible for Blood Pressure Regulation in Hypertensive Older Adults

To compare the effect of an intensity-controlled exercise program (ICEP) and a nonintensity-controlled exercise program (non-ICEP) on the variables responsible for blood pressure regulation in hypertensive older adults. 95 hypertensive older adults (65.40 ± 7.48 years/22 males and 73 females) performed hemodynamic, functional fitness, and biochemical evaluations before and after 12 weeks of the multicomponent exercises which included walking, muscle strength, hydrogymnastics, Pilates, dynamic balance, agility, flexibility, and others. A significant improvement was observed in general functional fitness index (GFFI: p ≤ 0.000, d = 0.35), nitrite (NO2 -: p ≤ 0.000, d = 0.49), systolic blood pressure (SBP: p ≤ 0.000, d = 0.65), diastolic blood pressure (DBP: p ≤ 0.013, d = 0.40), thiobarbituric acid reactive substances (TBARS: p ≤ 0.007, d = 0.78), activity of the endothelial superoxide dismutase enzyme (ecSOD: p ≤ 0.032, d = 0.41), double product (DP: p ≤ 0.015, d = 0.43), and waist-hip ratio (WHR: p ≤ 0.000, d = 0.44) for ICEP. Only GFFI (p ≤ 0.047, d = 0.12), TBARS (p ≤ 0.000, d = 0.77), SOD (p ≤ 0.025, d = 0.25), DP (p ≤ 0.046, d = 0.26), and BMI (p ≤ 0.018, d = 0.02) presented better results in non-ICEP. When the effect of the groups (controlled by age, BMI, and sex) was evaluated, an increase was observed in the NO2 -, TBARS, and SOD and a reduction in the SBP and WHR variables in the ICEP group compared to the non-ICEP group. Twelve weeks of engagement in a controlled-intensity exercise program was enough to improve the level of functional fitness and variables regarding blood pressure regulation in hypertensive older adults. Conversely, physical exercise performed without intensity control was related to the limited effect on such variables.

Is It Possible to Train the Endothelium?-A Narrative Literature Review

This review provides an overview of current knowledge regarding the adaptive effects of physical training on the endothelium. The endothelium plays a crucial role in maintaining the health of vessel walls and regulating vascular tone, structure, and homeostasis. Regular exercise, known for its promotion of cardiovascular health, can enhance endothelial function through various mechanisms. The specific health benefits derived from exercise are contingent upon the type and intensity of physical training. The review examines current clinical evidence supporting exercise's protective effects on the vascular endothelium and identifies potential therapeutic targets for endothelial dysfunction. There is an urgent need to develop preventive strategies and gain a deeper understanding of the distinct impacts of exercise on the endothelium.

Effects of mitochondrial dysfunction on cellular function: Role in atherosclerosis

Atherosclerosis, an immunoinflammatory disease of medium and large arteries, is associated with life-threatening clinical events, such as acute coronary syndromes and stroke. Chronic inflammation and impaired lipoprotein metabolism are considered to be among the leading causes of atherosclerosis, while numerous risk factors, including arterial hypertension, diabetes mellitus, obesity, and aging, can contribute to the development of the disease. In recent years, emerging evidence has underlined the key role of mitochondrial dysfunction in the pathogenesis of atherosclerosis. Mitochondrial dysfunction is believed to result in an increase in reactive oxygen species, leading to oxidative stress, chronic inflammation, and intracellular lipid deposition, all of which can contribute to the pathogenesis of atherosclerosis. Critical cells, including endothelial cells, vascular smooth muscle cells, and macrophages, play an important role in atherosclerosis. Mitochondrial function is also involved in maintaining the normal function of these cells. To better understand the relationship between mitochondrial dysfunction and atherosclerosis, this review summarizes the findings of recent studies and discusses the role of mitochondrial dysfunction in the risk factors and critical cells of atherosclerosis. FACTS: OPEN QUESTIONS.

Statin administration improves vascular function in heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction (HFpEF) is characterized by impaired vascular endothelial function that may be improved by hydroxy-methylglutaryl-CoA (HMG-CoA) reductase enzyme inhibition. Thus, using a parallel, double-blind, placebo-controlled design, this study evaluated the efficacy of 30-day atorvastatin administration (10 mg daily) on peripheral vascular function and biomarkers of inflammation and oxidative stress in 16 patients with HFpEF [Statin: n = 8, 74 ± 6 yr, ejection fraction (EF) 52-73%; Placebo: n = 8, 67 ± 9 yr, EF 56-72%]. Flow-mediated dilation (FMD) and sustained-stimulus FMD (SS-FMD) during handgrip (HG) exercise, reactive hyperemia (RH), and blood flow during HG exercise were evaluated to assess conduit vessel function, microvascular function, and exercising muscle blood flow, respectively. FMD improved following statin administration (pre, 3.33 ± 2.13%; post, 5.23 ± 1.35%; P < 0.01), but was unchanged in the placebo group. Likewise, SS-FMD, quantified using the slope of changes in brachial artery diameter in response to increases in shear rate, improved following statin administration (pre: 5.31e-5 ± 3.85e-5 mm/s-1; post: 8.54e-5 ± 4.98e-5 mm/s-1; P = 0.03), with no change in the placebo group. Reactive hyperemia and exercise hyperemia responses were unchanged in both statin and placebo groups. Statin administration decreased markers of lipid peroxidation (malondialdehyde, MDA) (pre, 0.652 ± 0.095; post, 0.501 ± 0.094; P = 0.04), whereas other inflammatory and oxidative stress biomarkers were unchanged. Together, these data provide new evidence for the efficacy of low-dose statin administration to improve brachial artery endothelium-dependent vasodilation, but not microvascular function or exercising limb blood flow, in patients with HFpEF, which may be due in part to reductions in oxidative stress.NEW & NOTEWORTHY This is the first study to investigate the impact of statin administration on vascular function and exercise hyperemia in patients with heart failure with preserved ejection fraction (HFpEF). In support of our hypothesis, both conventional flow-mediated dilation (FMD) testing and brachial artery vasodilation in response to sustained elevations in shear rate during handgrip exercise increased significantly in patients with HFpEF following statin administration, beneficial effects that were accompanied by a decrease in biomarkers of oxidative damage. However, contrary to our hypothesis, reactive hyperemia and exercise hyperemia were unchanged in patients with HFpEF following statin therapy. These data provide new evidence for the efficacy of low-dose statin administration to improve brachial artery endothelium-dependent vasodilation, but not microvascular reactivity or exercising muscle blood flow in patients with HFpEF, which may be due in part to reductions in oxidative stress.

Protective Role of Chronic Exercise Training in Modulating the Impact of Hyperglycemia on Vascular Sensitivity to Ischemia-Reperfusion

Hyperglycemia (HG) is associated with increased mortality and morbidity in acute ischemic events. Regardless of the tissue or organs involved, the vascular endothelium is a key target of ischemia-reperfusion (I/R) injury severity. Among endothelium-protective strategies, exercise has been widely described as useful. However, whether this strategy is able to impact the deleterious effect of HG on endothelial function during I/R has never been challenged. For this, 48 male Wistar rats were randomized into 4 groups: sedentary (Sed) or exercised (Ex, 45 min/day, 5 days/week for 5 weeks) rats, treated (hyperglycemic, HG) or not (normoglycemic, NG) with streptozotocin (40 mg/kg, 48 h before procedure). Vascular I/R (120/15 min) was performed by clamping the femoral artery. Arterial and downstream muscular perfusions were assessed using laser speckle contrast imaging. Vascular endothelial function was assessed in vivo 15 min after reperfusion. HG was responsible for impairment of reperfusion blood flow as well as endothelial function. Interestingly exercise was able to prevent those impairments in the HG group. In agreement with the previous results, HG increased reactive oxygen species production and decreased nitric oxide bioavailability whereas exercise training normalized these parameters. It, therefore, appears that exercise may be an effective prevention strategy against the exacerbation of vascular and muscular damage by hyperglycemia during I/R.

Association between endothelial nitric oxide synthase and the renin-angiotensin-aldosterone system polymorphisms, blood pressure and training status in normotensive/pre-hypertension and hypertensive older adults: a pilot study

Introduction:Variations in blood pressure (BP) are, in part, genetically determined and some polymorphisms of renin-angiotensin- aldosterone system (RAAS) and synthase of endothelial nitric oxide (eNOS) have been related to hypertension (HT). Conversely, physical exercise is considered a non-pharmacological tool for HT control, treatment, and prevention.Objective: The purpose of this study is to investigate the relationship between eNOS and RAAS polymorphisms, their epistatic interaction, and the respective humoral factors in the BP control in normotensive/pre-hypertension and hypertensive older adults and how this relationship can be modulated by training status (TS) level.Methods:A total of 155 older adults (66.94 ± 6.83 years old) performed the following evaluations: AAHPERD battery test to determine the general functional fitness index (GFFI), systolic and diastolic blood pressure (SBP and DBP), blood collection for DNA extraction, analysis of eNOS gene polymorphisms rs2070744; rs61722009 and rs1799983 and RAAS polymorphisms rs699; rs1799752 and rs5186, and quantification of ACE activity (Fluorimetric Assay) and nitrite concentration (Chemiluminescence Method).Results and Conclusion:Good TS level appears to exert greater influence on SBP for G2 and G3 (G1: 125.79 ± 14.03/ G2: 119.91 ± 11.72^/G3: 119.71 ± 10.85) and on NO₂ for G3 (G1: 0.42 ± 0.25/ G2: 0.54 ± 0.45/ G3: 0.71 ± 0.52). No associations were observed between eNOS and RAAS polymorphisms, but the epistasis was identified between eNOS polymorphism, rs2070744, and RAAS polymorphism, rs699, revealing a statistically significant interaction (p = .0235) with training score of 0.63, a training test accuracy of 0.61 and a cross-validation consistency of 10/10. This result suggests an increased risk of hypertension.

Serum endocan and endothelial dysfunction in childhood acute lymphoblastic leukemia survivors: a tertiary center experience

Background:

An increased risk of cardiovascular complications is reported in survivors of childhood acute lymphoblastic leukemia (ALL). Early identification of impaired vascular health may allow for early interventions to improve outcomes.

Aim:

The study was conducted to assess the endothelial dysfunction in ALL survivors using a new marker, serum endocan, and measurement of the mean common carotid arteries intima media thickness (cIMT).

Methods:

A case-control study was conducted on 100 childhood ALL survivors (aged 6–18 years), with 80 healthy age and sex-matched children as a control group. Lipid profile, hepatitis markers, and serum ferritin where measured, in addition to the measurement of serum endocan. and cIMT by B-mode high-resolution ultrasonography for all study participants.

Results:

Triglycerides, total cholesterol, post prandial glucose, and serum ferritin were significantly higher in ALL survivors than controls (p < 0.05). Dyslipidemia was detected in 6% of ALL survivors. ALL survivors showed statistically higher serum endocan levels (470.41 ± 556.1 ng/l, versus, 225.94 ± 185.2 ng/l, respectively) and increased cIMT levels compared with the control group (0.650 ± 0.129 mm versus 0.320 ± 0.095 mm, respectively) p < 0.05. Serum endocan was positively correlated with cIMT and blood cholesterol.

Conclusions:

The survivors of childhood ALL demonstrated an elevated level of serum endocan and increased cIMT. These can be used as predictors of endothelial dysfunction, and, as a consequence, the risk of developing premature atherosclerosis.

What type of physical exercise should be recommended for improving arterial stiffness on adult population? A network meta-analysis

AIMS

Physical exercise has been associated with a reduction in arterial stiffness, a subclinical process underlying cardiovascular disease. However, the effect of different types of exercise (aerobic, resistance, combined, interval training, stretching, or mind-body modalities) on arterial stiffness is unclear. This network meta-analysis aimed to examine the effectiveness of different types of exercise on arterial stiffness as measured by pulse wave velocity in adults.

METHODS AND RESULTS

We searched Cochrane Central Register of Controlled Trials, CINAHL, MEDLINE (via Pubmed), Embase, and Web of Science databases, for randomized clinical trials including at least a comparison group, from their inception to 30 June 2020. A frequentist network meta-analysis was performed to compare the effect of different types of physical exercise on arterial stiffness as measured by pulse wave velocity. Finally, 35 studies, with a total of 1125 participants for exercise intervention and 633 participants for the control group, were included. In the pairwise meta-analyses, the exercises that improved arterial stiffness were: interval training [effect size (ES) 0.37; 95% confidence interval (CI) 0.01-0.73], aerobic exercise (ES 0.30; 95% CI 0.13-0.48) and combined exercise (ES 0.22; 95% CI 0.04-0.40). Furthermore, the network meta-analysis showed that mind-body interventions were the most effective type of exercise to reduce the pulse wave velocity (ES 0.86; 95% CI 0.04-1.69). In addition, combined exercise (ES 0.35; 95% CI 0.08-0.62), aerobic exercise (ES 0.33; 95% CI 0.09-0.57), and interval training (ES 0.33; 95% CI 0.02-0.64) showed significant improvements.

CONCLUSION

Our findings showed that aerobic exercise, combined exercise, interval training, and mind-body exercises were the most effective exercise modalities for reducing arterial stiffness, assuming an important role in the prevention of cardiovascular diseases.

Preclinical techniques to investigate exercise training in vascular pathophysiology

Atherosclerosis is a dynamic process starting with endothelial dysfunction and inflammation and eventually leading to life-threatening arterial plaques. Exercise generally improves endothelial function in a dose-dependent manner by altering hemodynamics, specifically by increased arterial pressure, pulsatility, and shear stress. However, athletes who regularly participate in high-intensity training can develop arterial plaques, suggesting alternative mechanisms through which excessive exercise promotes vascular disease. Understanding the mechanisms that drive atherosclerosis in sedentary versus exercise states may lead to novel rehabilitative methods aimed at improving exercise compliance and physical activity. Preclinical tools, including in vitro cell assays, in vivo animal models, and in silico computational methods, broaden our capabilities to study the mechanisms through which exercise impacts atherogenesis, from molecular maladaptation to vascular remodeling. Here, we describe how preclinical research tools have and can be used to study exercise effects on atherosclerosis. We then propose how advanced bioengineering techniques can be used to address gaps in our current understanding of vascular pathophysiology, including integrating in vitro, in vivo, and in silico studies across multiple tissue systems and size scales. Improving our understanding of the antiatherogenic exercise effects will enable engaging, targeted, and individualized exercise recommendations to promote cardiovascular health rather than treating cardiovascular disease that results from a sedentary lifestyle.

Chronic Iron Overload Restrains the Benefits of Aerobic Exercise to the Vasculature

Physical exercise is a well-recognized effective non-pharmacological therapy for cardiovascular diseases. However, because iron is essential element in many physiological processes including hemoglobin and myoglobin synthesis, thereby playing a role on oxygen transport, many athletes use iron supplement to improve physical performance. Regarding this, iron overload is associated with oxidative stress and damage to various systems, including cardiovascular. Thus, we aimed to identify the vascular effects of aerobic exercise in a rat model of iron overload. Male Wistar rats were treated with 100 mg/kg/day iron-dextran, i.p., 5 days a week for 4 weeks, and then underwent aerobic exercise protocol on a treadmill at moderate intensity, 60 min/day, 5 days a week for 8 weeks. Exercise reduced vasoconstrictor response of isolated aortic rings by increasing participation of nitric oxide (NO) and reducing oxidative stress, but these benefits to the vasculature were not observed in rats previously subjected to iron overload. The reduced vasoconstriction in the exercised group was reversed by incubation with superoxide dismutase (SOD) inhibitor, suggesting that increased SOD activity by exercise was lost in iron overload rats. Iron overload groups increased serum levels of iron, transferrin saturation, and iron deposition in the liver, gastrocnemius muscle, and aorta, and the catalase was overexpressed in the aorta probably as a compensatory mechanism to the increased oxidative stress. In conclusion, despite the known beneficial effects of aerobic exercise on vasculature, our results indicate that previous iron overload impeded the anticontractile effect mediated by increased NO bioavailability and endogenous antioxidant response due to exercise protocol.

Mitochondrial Dysfunction and DNA Damage in the Context of Pathogenesis of Atherosclerosis

Atherosclerosis is a multifactorial disease of the cardiovascular system associated with aging, inflammation, and oxidative stress. An important role in the development of atherosclerosis play elevated plasma lipoproteins. A number of external factors (smoking, diabetes, infections) can also contribute to the development of the disease. For a long time, atherosclerosis remains asymptomatic, therefore, the search for early markers of the disease is critical for the timely management and better outcomes for patients. Mitochondrial dysfunction and mitochondrial DNA (mtDNA) damage appear to connect different aspects of atherosclerosis pathogenesis. To date, multiple lines of research have demonstrated the strong association of mitochondrial dysfunction with the development of various human diseases. Therapies aimed at restoring the mitochondrial function are being actively developed, and are expected to broaden the therapeutic possibilities for several chronic human diseases. The development of such therapies depends on our understanding of the functional roles of different mtDNA variants associated with one or another disorder, and the molecular mechanisms linking mitochondrial dysfunction with a given pathological feature. These questions are, however, challenging and require future intensive research. This review summarizes the recent studies and describes the central processes of the development of atherosclerosis, and shows their relationship with mitochondrial dysfunction. One of the promising therapeutic approaches for future atherosclerosis treatments is the use of mitochondria-targeted antioxidants. Future studies should focus on characterizing the mechanisms of mitochondrial involvement in cardiovascular pathologies to better direct the search for novel therapies.

Global REACH 2018: High Blood Viscosity and Hemoglobin Concentration Contribute to Reduced Flow-Mediated Dilation in High-Altitude Excessive Erythrocytosis

Excessive erythrocytosis (EE; hemoglobin concentration [Hb] ≥21 g/dL in adult males) is associated with increased cardiovascular risk in highlander Andeans. We sought to quantify shear stress and assess endothelial function via flow-mediated dilation (FMD) in male Andeans with and without EE. We hypothesized that FMD would be impaired in Andeans with EE after accounting for shear stress and that FMD would improve after isovolemic hemodilution. Brachial artery shear stress and FMD were assessed in 23 male Andeans without EE (age: 40±15 years [mean±SD]; Hb<21 g/dL) and 19 male Andeans with EE (age: 43±14 years; Hb≥21 g/dL) in Cerro de Pasco, Peru (4330 m). Shear stress was quantified from Duplex ultrasound measures of shear rate and blood viscosity. In a subset of participants (n=8), FMD was performed before and after isovolemic hemodilution with blood volume replaced by an equal volume of human serum albumin. Blood viscosity and Hb were 48% and 23% higher (both P<0.001) and FMD was 28% lower after adjusting for the shear stress stimulus ( P=0.013) in Andeans with EE compared to those without. FMD was inversely correlated with blood viscosity ( r²=0.303; P<0.001) and Hb ( r²=0.230; P=0.001). Isovolemic hemodilution decreased blood viscosity by 30±10% and Hb by 14±5% (both P<0.001) and improved shear stress stimulus-adjusted FMD from 2.7±1.9% to 4.3±1.9% ( P=0.022). Hyperviscosity, high Hb, or both, actively contribute to acutely reversible impairments in FMD in EE, suggesting that this plays a pathogenic role in the increased cardiovascular risk.

Oxidative Stress and Inflammation, Key Targets of Atherosclerotic Plaque Progression and Vulnerability: Potential Impact of Physical Activity

Atherosclerosis, a complex cardiovascular disease, is a leading cause of mortality and morbidity worldwide. Oxidative stress and inflammation are both involved in the development of atherosclerotic plaque as they increase the biological processes associated with this pathology, such as endothelial dysfunction and macrophage recruitment and adhesion. Atherosclerotic plaque rupture leading to major ischemic events is the result of vulnerable plaque progression, which is a result of the detrimental effect of oxidative stress and inflammation on risk factors for atherosclerotic plaque rupture, such as intraplaque hemorrhage, neovascularization, and fibrous cap thickness. Thus, both are key targets for primary and secondary interventions. It is well recognized that chronic physical activity attenuates oxidative stress in healthy subjects via the improvement of antioxidant enzyme capacities and inflammation via the enhancement of anti-inflammatory molecules. Moreover, it was recently shown that chronic physical activity could decrease oxidative stress and inflammation in atherosclerotic patients. The aim of this review is to summarize the role of oxidative stress and inflammation in atherosclerosis and the results of therapeutic interventions targeting them in both preclinical and clinical studies. The effects of chronic physical activity on these two key processes are then reviewed in vulnerable atherosclerotic plaques in both coronary and carotid arteries.

High Bubble Grade After Diving: The Role of the Blood Pressure Regimen

Introduction: Previous studies have suggested that the circulatory system was involved in the production of circulatory bubbles after diving. This study was designed to research the cardio-vascular function characteristics related to the production of high bubble grades after diving.

Methods: Thirty trained divers were investigated both at baseline and after a 30-msw SCUBA dive. At baseline, the investigations included blood pressure measurement, echocardiography, and assessment of aerobic fitness using VO₂ peak measurement. Blood samples were taken at rest, to measure the plasma concentration of NOx and endothelin-1. After diving, circulating bubbles were detected in the pulmonary artery by pulsed Doppler at 20-min intervals during the 90 min after surfacing. The global bubble quantity production was estimated by the KISS index.

Results: Divers with a high bubble grade (KISS > 7.5) had systolic blood pressure, pulse pressure, weight, and height significantly higher than divers with a low bubble grade. By contrast, total arterial compliance, plasma NOx level, and percentage of predicted value of peak oxygen uptake were significantly lower in divers with a high bubble grade. Cardiac dimensions, left ventricular function, and plasma endothelin-1 concentration were not significantly different between groups. The multivariate analysis identified blood pressure as the main contributor of the quantity of bubble production. The model including pulse pressure, plasma NOx level, and percentage of predicted value of peak oxygen uptake has an explanatory power of 49.22%.

Conclusion: The viscoelastic properties of the arterial tree appeared to be an important contributor to the circulating bubble production after a dive.

Effects of Riot Control Training on Systemic Microvascular Reactivity and Capillary Density

Introduction

The main aim of the present study is to evaluate the effects of strenuous exercise, related to special military training for riot control, on systemic microvascular endothelial function and skin capillary density.

Materials and Methods

Endothelium-dependent microvascular reactivity was evaluated in the forearm skin of healthy military trainees (age 23.4 ± 2.3 yr; n = 15) using laser speckle contrast imaging coupled with cutaneous acetylcholine (ACh) iontophoresis and post-occlusive reactive hyperemia (PORH). Functional capillary density was assessed using high-resolution, intra-vital color microscopy in the dorsum of the middle phalanx. Capillary recruitment (capillary reserve) was evaluated using PORH. Microcirculatory tests were performed before and after a 5-wk special military training for riot control.

Results

Microvascular endothelium-dependent vasodilatory responses were markedly and significantly reduced after training, compared with values obtained before training. The peak values of microvascular conductance obtained during iontophoresis of ACh or PORH before training (0.84 ± 0.22 and 0.94 ± 0.72 APU/mmHg, respectively) were markedly reduced after training (0.47 ± 0.11 and 0.71 ± 0.14 APU/mmHg; p < 0.0001 and p = 0.0037, respectively). Endothelium-dependent capillary recruitment was significantly reduced after training (before 101 ± 9 and after 95 ± 8 capillaries/mm2; p = 0.0007).

Conclusions

The present study showed that a 5-wk strenuous military training, performed in unfavorable climatic conditions, induces marked systemic microvascular dysfunction, mainly characterized by reduced endothelium-dependent microvascular vasodilation and blunted capillary recruitment.

Intermittent versus constant aerobic exercise in middle-aged males: acute effects on arterial stiffness and factors influencing the changes

PURPOSE

Both constant and intermittent acute aerobic exercises have been found to decrease arterial stiffness. However, direct comparisons of these two types of exercise are sparse. It is not known which type of exercise has the greatest effect.

METHODS

We evaluated the haemodynamic responses in 15 males (age 48.5 ± 1.3 years; BMI 27.5 ± 0.8 kg m^-2) following acute constant (CE) and intermittent cycling exercise (IE). Duration and heart rate were matched during both exercises (131.8 ± 3.2 bpm for CE and 132.0 ± 3.1 bpm for IE). Central and peripheral arterial stiffness was assessed through pulse wave velocity (PWV). Plasma concentrations of nitric oxide (NO), atrial natriuretic peptide (ANP), blood lactate, noradrenaline, and adrenaline were measured before and after each exercise.

RESULTS

Central (+ 1.8 ± 7.4 and - 6.5 ± 6.8% for CE and IE) and upper limb PWV (+ 2.7 ± 6.2 and - 8 ± 4.6% for CE and IE) were not significantly altered although a small decrease (small effect size) was observed after IE. However, lower limb PWV significantly decreased after exercises (- 7.3 ± 5.7 and - 15.9 ± 4% after CE and IE), with a larger effect after IE.

CONCLUSIONS

Greater decrease in lower limb PWV occurred after IE despite greater heart rate. This may be due to the higher blood levels of lactate during IE, while NO, ANP, noradrenaline, and adrenaline levels remained not statistically different from CE. These results underlined the importance of lactate in triggering the post-exercise vascular response to exercise, as well as its regional characteristic.

Higher Daily Physical Activity Level Is Associated with Lower RBC Aggregation in Carotid Artery Disease Patients at High Risk of Stroke

Aim: Carotid artery disease (CAD) is an atherosclerotic inflammatory disease that affects the arterial wall, specifically at points of bifurcation where blood flow is disturbed. Abnormal blood rheology could participate in the pathophysiology of ischemic cardiovascular disease. Physical activity (PA) is known to improve blood rheology in several chronic disorders. This study aims to (i) compare the hemorheological profile of CAD patients and controls and (ii) investigate the associations between daily PA and hemorheological parameters in CAD patients. Methods: Blood viscosity, red blood cell (RBC) aggregation and RBC deformability were assessed in 80 patients (15 symptomatic and 65 asymptomatic) and 14 age-matched controls. Patients' PA levels were evaluated using questionnaires. Results: Symptomatic patients showed increased blood viscosity and RBC aggregation compared to healthy controls. RBC aggregation was significantly lower in the most physically active patients compared to the least physically active ones. Blood viscosity and RBC deformability did not vary according to physical activity level. Conclusions: Our results showed greater hemorheological abnormalities (blood hyper-viscosity and hyper-aggregation of red blood cells) in the most severe CAD patients, which could exacerbate the risk of stroke in patients with stenosis. As the most physically active patients had lower RBC aggregation than those who were less physically active, it is possible that regular PA may limit hemorheological alterations in CAD patients.

Carbohydrate restriction with postmeal walking effectively mitigates postprandial hyperglycemia and improves endothelial function in type 2 diabetes

Postprandial hyperglycemia has deleterious effects on endothelial function. Restricting carbohydrate intake and postmeal walking have each been shown to reduce postprandial hyperglycemia, but their combination and subsequent effects on endothelial function have not been investigated. Here, we sought to examine the effect of blunting postprandial hyperglycemia by following a low-carbohydrate diet, with or without postmeal walking exercise, on markers of vascular health in type 2 diabetes (T2D). In a randomized crossover design, individuals with T2D ( n = 11) completed three 4-day controlled diet interventions consisting of 1) low-carbohydrate diet alone (LC), 2) low-carbohydrate diet with 15-min postmeal walks (LC + Ex), and 3) low-fat control diet (CON). Fasting blood samples and brachial artery flow-mediated dilation (%FMD) were measured before and after each intervention. Total circulating microparticles (MPs), endothelial MPs, platelet MPs, monocyte-platelet aggregates, and adhesion molecules were assessed as biomarkers of vascular health. There was a significant condition × time interaction for %FMD ( P = 0.01), with post hoc tests revealing improved %FMD after LC + Ex (+0.8 ± 1.0%, P = 0.02), with no change after LC or CON. Endothelial MPs were significantly reduced with the LC diet by ~45% (from 99 ± 60 to 44 ± 31 MPs/μl, P = 0.02), with no change after LC + Ex or CON (interaction: P = 0.04). Total MPs were lower (main effect time: P = 0.02), whereas monocyte-platelet aggregates were higher (main effect time: P < 0.01) after all interventions. Plasma adhesion molecules and C-reactive protein were unaltered. Attenuating postprandial hyperglycemic excursions using a low-carbohydrate diet combined with postmeal walking appears to be an effective strategy to improve endothelial function in individuals with T2D. NEW & NOTEWORTHY Carbohydrate restriction and postmeal walking lower postprandial hyperglycemia in individuals with type 2 diabetes. Here, we show that the combination significantly improved endothelial function and that carbohydrate restriction alone reduced circulating endothelial microparticles in individuals with type 2 diabetes. Listen to this article's corresponding podcast at http://ajpheart.podbean.com/e/low-carb-diet-and-exercise-improve-endothelial-health/ .

NO-Synthase Activity in Patients with Coronary Heart Disease Associated with Hypertension of Different Age Groups

Background

Coronary heart disease is the leading cause of death and disability worldwide. Hypertension is a major independent risk factor for the development of CHD. Abnormalities in NO generation or activity have been proposed as a major mechanism of CHD. The purpose of this article is to determine the activity of eNOS and iNOS in patients with isolated CHD and CHD associated with HT of different age groups.

Methods

Fifty patients with isolated CHD and 42 patients with CHD associated with HT were enrolled in this study. NOS activity was determined by nitrite anion formed in the reaction.

Results

A statistically significant increase in iNOS activity is observed in elderly donors. In patients with isolated coronary heart disease cNOS activity is statistically significantly reduced with respect to the control group. The reduction of enzymatic activity of cNOS is more expressed in elderly patients than in middle-aged patients with coronary heart disease. Alterations in eNOS activity are more expressed in patients with coronary heart disease associated with hypertension than in patients with isolated coronary heart disease. Against the background of cNOS inhibition in the patients, a sharp increase in iNOS activity is observed.

Conclusions

It has been shown that disturbance of endothelial function in patients with coronary heart disease associated with hypertension is characterized by reduced endothelial NO synthesis by cNOS and increased systemic NO synthesis due to increased iNOS activity. It has been found that the lack of endothelial NO and hyperproduction of »harmful« NO by iNOS are more expressed in elderly patients.

The role of inhibition of nitric oxide synthesis in the aggregation of platelets due to the stimulated production of thromboxane A2

The aggregation of platelets by ADP is reported to be mediated through prostaglandin synthesis. In contrast, nitric oxide is known to inhibit platelet aggregation through the synthesis of cyclic AMP and cyclic GMP. Studies were conducted to determine the role of ADP, if any, on the synthesis of nitric oxide in platelets. Both normal male and female volunteers between the ages of 30 and 45 years participated in the study. Thromboxane A2 (TXA2) was measured as thromboxane B2 by ELISA. Nitric oxide was measured by methhaemoglobin method. It was found that the treatment of platelet-rich plasma (PRP) with different concentrations of ADP (0-8.0 μmol/l) resulted in increased platelet aggregation, and at 8.0 μmol/l ADP, the basal nitric oxide level was found to be maximally decreased from 0.3 ± 0.10 nmol/10 platelets to 0 nmol/10 platelets in PRP (P < 0.0001; n = 10). Line-weaver-Burk plot of nitric oxide synthase (NOS) activity in the presence of 2.0 μmol/l ADP reduced the Vmax from 6.662 to 2.22 nmol nitric oxide/h per mg protein compared with control. Inhibition of nitric oxide synthesis by N-methyl-L-arginine acetate ester (L-NAME), an inhibitor of NOS, was found to aggregate platelets due to the reduction of platelet nitric oxide level (Pearson's coefficient of correlation, r =  -0.986, P < 0.001, n = 10). The treatment of PRP to L-NAME was found to increase TXA2 synthesis to 1.679 ± 0.05 from 0 pmol/10 platelets. These results suggested that inhibition of NOS in platelets resulted in platelet aggregation through TXA2 synthesis in PRP through a novel pathway.

An update of the role of renin angiotensin in cardiovascular homeostasis

The renin angiotensin system (RAS) is thought to be the body's main vasoconstrictor system, with physiological effects mediated via the interaction of angiotensin II with angiotensin I receptors (the "classic" RAS model). However, since the discovery of the heptapeptide angiotensin 1-7 and the development of the concept of the "alternate" RAS system, with its ability to reduce arterial blood pressure, our understanding of this physiologic system has changed dramatically. In this review, we focus on the newly discovered functions of the RAS, particularly the potential clinical significance of these developments, especially in the realm of new pharmacologic interventions for treating cardiovascular disease.

Endothelial health in childhood acute lymphoid leukemia survivors: pilot evaluation with peripheral artery tonometry

BACKGROUND

Childhood cancer survivors are a growing population at risk for poor cardiac outcomes. Acute lymphoid leukemia (ALL) survivors are among those at increased risk of cardiovascular complications. Early identification of impaired vascular health may allow for interventions to improve these outcomes. The purpose of this study was to evaluate vascular health using peripheral artery tonometry in ALL survivors and compare results with healthy siblings.

PROCEDURE

Sixteen ALL survivor, healthy sibling pairs, aged 8 to 20 years, were evaluated for vascular health and cardiovascular risk factors (body mass index, central adiposity, blood pressure, and fitness). One-tailed paired t test was used to compare the groups.

RESULTS

Survivors were similar to siblings in cardiovascular risk measures but had poorer vascular health as measured by reactive hyperemia index (survivor RHI 1.54 vs. sibling 1.77; P=0.0474).

CONCLUSION

This study reveals that even among survivors who are comparable to their healthy siblings in other traditional cardiovascular risks, there is evidence of poorer vascular health.

Nitric oxide and mitochondria in metabolic syndrome

Metabolic syndrome (MS) is a cluster of metabolic disorders that collectively increase the risk of cardiovascular disease. Nitric oxide (NO) plays a crucial role in the pathogeneses of MS components and is involved in different mitochondrial signaling pathways that control respiration and apoptosis. The present review summarizes the recent information regarding the interrelations of mitochondria and NO in MS. Changes in the activities of different NO synthase isoforms lead to the formation of metabolic disorders and therefore are highlighted here. Reduced endothelial NOS activity and NO bioavailability, as the main factors underlying the endothelial dysfunction that occurs in MS, are discussed in this review in relation to mitochondrial dysfunction. We also focus on potential therapeutic strategies involving NO signaling pathways that can be used to treat patients with metabolic disorders associated with mitochondrial dysfunction. The article may help researchers develop new approaches for the diagnosis, prevention and treatment of MS.

Exercise and NO production: relevance and implications in the cardiopulmonary system

This article reviews the existing knowledge about the effects of physical exercise on nitric oxide (NO) production in the cardiopulmonary system. The authors review the sources of NO in the cardiopulmonary system; involvement of three forms of NO synthases (eNOS, nNOS, and iNOS) in exercise physiology; exercise-induced modulation of NO and/or NOS in physiological and pathophysiological conditions in human subjects and animal models in the absence and presence of pharmacological modulators; and significance of exercise-induced NO production in health and disease. The authors suggest that physical activity significantly improves functioning of the cardiovascular system through an increase in NO bioavailability, potentiation of antioxidant defense, and decrease in the expression of reactive oxygen species-forming enzymes. Regular physical exercises are considered a useful approach to treat cardiovascular diseases. Future studies should focus on detailed identification of (i) the exercise-mediated mechanisms of NO exchange; (ii) optimal exercise approaches to improve cardiovascular function in health and disease; and (iii) physical effort thresholds.

Influence of training status and eNOS haplotypes on plasma nitrite concentrations in normotensive older adults: a hypothesis-generating study

The purpose of this study was to evaluate the relationship between 3 eNOS gene polymorphisms and training status (TS) in affecting plasma nitrite concentration (NO2) in normotensive adults over 50 years old. Resting blood pressure (BP) was measured in all participants (n = 101). Plasma was taken to analyze: lipid profile, nitrite concentration (NO2) and lipid peroxide levels (T-BARS). Also, genomic DNA was extracted from plasma for genotyping NOS3 polymorphisms (-786T>C; 894G>T; and VNTR in intron 4). TS was determined by one-mile walk test and Functional Fitness Test Battery from AAHPERD (TS1-regular TS; TS2-good TS; and TS3-very good TS). BP was not influenced by TS, but NO2 was 15% higher in TS3 (123 ± 27 nM) compared to TS-2 (106 ± 22 nM). No differences were found in plasma NO2 in the haplotype analyses. However, the presence of the C allele (T-786C) and ASP allele (Glu298Asp) was found to enhance the correlation between TS and NO2 levels (r = 0.492 in C/4b/ASP haplotype and r = 0.855 in C/4a/ASP haplotype). This study thus identifies NOS3 polymorphism-dependent sensitivity to the effects of physical training on plasma NO2. Maintenance of good levels of training status, in carriers of C allele for T-786C polymorphism, combined with ASP allele for Glu298Asp polymorphism, may result in an increase in the NO2 plasma concentrations, which may reflect improved NO bioavailability in older adult normotensive individuals.

Superoxide production pathways in aortas of diabetic rats: beneficial effects of insulin therapy and endurance training

Superoxide (O 2 (·-) ) overproduction, by decreasing the nitric oxide ((·)NO) bioavailability, contributes to vascular complications in type 1 diabetes. In this disease, the vascular O 2 (·-) can be produced by the NADPH oxidase (NOX), nitric oxide synthase (NOS), and xanthine oxidase (XO). This study aimed to determine the contribution of each enzymatic pathway in hyperglycemia-induced O 2 (·-) overproduction, and the effects of an endurance training program and insulin therapy, associated or not, on the O 2 (·-) production (amount and related enzymes) in diabetic rats. Forty male Wistar rats were divided into diabetic (D), diabetic treated with insulin (D-Ins), diabetic trained (D-Tr), or diabetic insulin-treated and trained (D-Ins + Tr) groups. An additional healthy group was used as control. Insulin therapy (Glargine Lantus, Sanofi) and endurance training (treadmill run: 60 min/day, 25 m/min, 5 days/week) started 1 week after diabetes induction by streptozotocin (45 mg/kg), and lasted for 8 weeks. At the end of the protocol, the O 2 (·-) production in aorta rings was evaluated by histochemical analyses (DHE staining). Each production pathway was studied by inhibiting NOX (apocynin), NOS (L-Name), or XO (allopurinol) before DHE staining. Diabetic rats exhibited hyperglycemia-induced O 2 (·-) overproduction, resulting from NOX, NOS, and XO activation. Insulin therapy and endurance training, associated or not, decreased efficiently and similarly the O 2 (·-) overproduction. Insulin therapy reduced the hyperglycemia and decreased the three enzymatic pathways implicated in the O 2 (·-) production. Endurance training decreased directly the NOS and XO activity. While both therapeutic strategies activated different pathways, their association did not reduce the O 2 (·-) overproduction more significantly.

Adrenoreceptors and nitric oxide in the cardiovascular system

Nitric Oxide (NO) is a small molecule that continues to attract much attention from the scientific community. Since its discovery, it has been evident that NO has a crucial role in the modulation of vascular tone. Moreover, NO is involved in multiple signal transduction pathways thus contributing to the regulation of many cellular functions. NO effects can be either dependent or independent on cGMP, and rely also upon several mechanisms such as the amount of NO, the compartmentalization of the enzymes responsible for its biosynthesis (NOS), and the local redox conditions. Several evidences highlighted the correlation among adrenoreceptors activity, vascular redox status and NO bioavailability. It was suggested a possible crosstalk between NO and oxidative stress hallmarks in the endothelium function and adaptation, and in sympathetic vasoconstriction control. Adrenergic vasoconstriction is a balance between a direct vasoconstrictive effect on smooth muscle and an indirect vasorelaxant action caused by α₂- and β-adrenergic endothelial receptor-triggered NO release. An increased oxidative stress and a reduction of NO bioavailability shifts this equilibrium causing the enhanced vascular adrenergic responsiveness observed in hypertension. The activity of NOS contributes to manage the adrenergic pathway, thus supporting the idea that the endothelium might control or facilitate β-adrenergic effects on the vessels and the polymorphic variants in β₂-receptors and NOS isoforms could influence aging, some pathological conditions and individual responses to drugs. This seems to be dependent, almost in part, on differences in the control of vascular tone exerted by NO. Given its involvement in such important mechanisms, the NO pathway is implicated in aging process and in both cardiovascular and non-cardiovascular conditions. Thus, it is essential to pinpoint NO involvement in the regulation of vascular tone for the effective clinical/therapeutic management of cardiovascular diseases (CVD).

eNOSI4 and EPHX1 polymorphisms affect maternal susceptibility to preeclampsia: analysis of five polymorphisms predisposing to cardiovascular disease in 279 Caucasian and 241 African women

PURPOSE

The aim of this study was to evaluate possible associations of genetic polymorphisms predisposing to cardiovascular disease with the development and/or the severity of preeclampsia.

METHODS

A two hospital-based prospective case-control study was performed in Germany and Ghana. 470 blood samples of 250 Caucasian and 220 black African have been genotyped by pyrosequencing and fragment length analysis. We evaluated the distribution of the epoxide hydrolase 1 (EPHX1) polymorphism on exon 3, the endothelial nitric oxide synthase (eNOS) polymorphisms on exon 7 and on intron 4, the angiotensinogen polymorphism on exon 2 and the estrogen receptor 1 polymorphism in intron 1.

RESULTS

74 Caucasian and 84 African were classified as preeclampsia with 27 Caucasian developing a hemolysis, elevated liver enzymes and low platelets (HELLP) syndrome and 17 African women experiencing eclampsia. Multivariate logistic regression analysis adjusting for ethnicity, age and parity revealed for carriers of eNOSI4 VNTR4a a 1.7-fold increased (95% CI 1.10-2.711, p = 0.016) risk to develop preeclampsia and a 3.6-fold increase for carriers of the EPHX1 113Tyr (95% CI 1.366-8.750, p = 0.009) to develop severest preeclampsia.

CONCLUSION

Our finding of eNOSI4 polymorphism predisposing to preeclampsia independently of ethnicity, age and parity supports the concept of NO being involved in the endothelial disorder preeclampsia. Since EPHX1 is highly expressed in the liver, can interact with various signaling pathways and is involved in central nervous system disorders, the association of EPHX1 polymorphism with the HELLP syndrome and eclampsia may hint to EPHX being a further key player in the pathogenesis of preeclampsia.

Roles of insulin, age, and asymmetric dimethylarginine on nitric oxide synthesis in vivo

We tested the effects of insulin on production of nitrous oxide (NO)-related substances (nitrites and nitrates [NOx]) after (15)N-arginine intravenous infusion and on asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA) concentrations in conditions reportedly associated with altered NO availability, i.e., aging, hypertension, hypercholesterolemia, and type 2 diabetes mellitus (T2DM). A total of 26 male subjects (age 23-71 years, BMI 23-33 kg/m(2)), some of whom were affected by mixed pathologic features, were enrolled. NOx fractional synthesis rate (FSR) was lower in elderly (P < 0.015) and T2DM subjects (P < 0.03) than in matched control subjects. Hyperinsulinemia generally increased both NOx FSR and absolute synthesis rate (ASR) and reduced NOx, ADMA, and SDMA concentrations. Insulin sensitivity was impaired only in T2DM. With use of simple linear regression analysis across all subjects, age was inversely correlated with both NOx FSR (R(2) = 0.23, P < 0.015) and ASR (R(2) = 0.21, P < 0.02). NOx FSR inversely correlated with both ADMA and SDMA. With use of multiple regression analysis and various models, NOx FSR remained inversely associated with age and ADMA, whereas ASR was inversely associated with age and diabetes. No association with insulin sensitivity was found. We conclude that whole-body NOx production is decreased in aging and T2DM. Age, ADMA concentration, and T2DM, but not insulin resistance, appear as negative regulators of whole-body NOx production.

Acute superoxide scavenging reduces sympathetic vasoconstrictor responsiveness in short-term exercise-trained rats

We hypothesized that acute superoxide (O2−) scavenging would attenuate sympathetic vasoconstrictor responsiveness by augmenting nitric oxide (NO)-mediated inhibition of sympathetic vasoconstriction in exercise-trained rats. Sprague-Dawley rats were randomly assigned to sedentary time control (S; n = 7) or mild- (M: 20 m/min, 5° grade; n = 7) or heavy-intensity (H: 40 m/min, 5° grade; n = 7) exercise training (ET) groups and trained 5 days/wk for 4 wk with matched training volume. Following ET, rats were anesthetized and instrumented for lumbar sympathetic chain stimulation and measurement of femoral vascular conductance. In resting skeletal muscle, the percentage change of femoral vascular conductance in response to continuous (2 Hz) and patterned (20 and 40 Hz) sympathetic stimulation was determined during control conditions, O2− scavenging (TIRON, 1 g·kg−1·h−1 iv) and combined O2− scavenging + nitric oxide synthase blockade ( Nω-nitro-l-arginine methyl ester, 5 mg/kg iv). ET augmented the vasoconstrictor response to sympathetic stimulation in a training intensity-dependent manner ( P < 0.05) (S: 2 Hz: −26 ± 7.1%; 20 Hz: −26.9 ± 7.3%; 40 Hz: −27.7 ± 7.0%; M: 2 Hz: −37.4 ± 8.3%; 20 Hz: −35.9 ± 7.4%; 40 Hz: −38.2 ± 9.4%; H: 2 Hz: −46.9 ± 7.8%; 20 Hz: −48.5 ± 7.2%; 40 Hz: −51.2 ± 7.3%). O2− scavenging did not alter ( P > 0.05) the vasoconstrictor response in S rats (S: 2 Hz: −23.9 ± 7.6%; 20 Hz: −26.1 ± 9.1%; 40 Hz: −27.5 ± 7.2%), whereas the response in ET rats was diminished (M: 2 Hz: −26.3 ± 5.1%; 20 Hz: −28.7 ± 5.3%; 40 Hz: −28.5 ± 5.6%; H: 2 Hz: −35.5 ± 10.3%; 20 Hz: −38.6 ± 6.8%; 40 Hz: −43.9 ± 5.9%, P < 0.05). TIRON + Nω-nitro-l-arginine methyl ester increased vasoconstrictor responsiveness ( P < 0.05) in ET rats (M: 2 Hz: −47.7 ± 9.8%; 20 Hz: −41.2 ± 7.2%; 40 Hz: −50.5 ± 7.9%; H: 2 Hz: −55.8 ± 7.6%; 20 Hz: −55.7 ± 7.8%; 40 Hz: −58.7 ± 6.2%), whereas, in S rats, the response was unchanged (2 Hz: −29.4 ± 8.7%; 20 Hz: −30.0 ± 7.4%; 40 Hz: −35.2 ± 10.3%; P > 0.05). These data indicate that the augmented sympathetic vasoconstrictor responsiveness in ET rats was related to increased oxidative stress and altered nitric oxide-mediated inhibition of vasoconstriction.

Submaximal PPARγ activation and endothelial dysfunction: new perspectives for the management of cardiovascular disorders

PPARγ activation plays an important role in glucose metabolism by enhancing insulin sensitization. PPARγ is a primary target for thiazolidinedione-structured insulin sensitizers like pioglitazone and rosiglitazone employed for the treatment of type 2 diabetes mellitus. Additionally, PPARγ activation inhibits adhesion cascades and detrimental vascular inflammatory events. Importantly, activation of PPARγ plays a distinctive role in regulating the physiology and expression of endothelial nitric oxide synthase (eNOS) in the endothelium, resulting in enhanced generation of vascular nitric oxide. The PPARγ activation-mediated vascular anti-inflammatory and direct endothelial functional regulatory actions could, therefore, be beneficial in improving the vascular function in patients with atherosclerosis and hypertension with or without diabetes mellitus. Despite the disappointing cardiac side effect profile of rosiglitazone-like PPARγ full agonists, the therapeutic potential of novel pharmacological agents targeting PPARγ submaximally cannot be ruled out. This review discusses the potential regulatory role of PPARγ on eNOS expression and activation in improving the function of vascular endothelium. We argue that partial/submaximal activation of PPARγ could be a major target for vascular endothelial functional improvement. Interestingly, newly synthesized partial agonists of PPARγ such as balaglitazone, MBX-102, MK-0533, PAR-1622, PAM-1616, KR-62776 and SPPARγM5 are devoid of or have a reduced tendency to cause the adverse effects associated with full agonists of PPARγ. We propose that the vascular protective properties of pharmacological agents, which submaximally activate PPARγ, should be investigated. Moreover, the therapeutic opportunities of agents that submaximally activate PPARγ in preventing vascular endothelial dysfunction (VED) and VED-associated cardiovascular disorders are discussed.

Efeitos do exercício físico no controle da hipertensão arterial em idosos: uma revisão sistemática

O exercício físico é uma das principais terapêuticas utilizadas para o paciente hipertenso, pois reduz a pressão arterial (PA) e os fatores de risco cardiovasculares, diminuindo a morbimortalidade. OBJETIVO: Analisar os efeitos do exercício físico na PA de idosos hipertensos, com base nos resultados de pesquisas empíricas realizadas no período de 2000 a 2010. METODOLOGIA: Revisão sistemática de estudos experimentais, em inglês, português e espanhol, nas bases eletrônicas MEDLINE, PubMed, Lilacs, Cochrane e PEDro, publicados entre 2000 e 2010, utilizando os descritores hipertensão, atividade física, exercício físico, idoso, exercício aeróbio e treinamento de resistência. RESULTADOS: Foram encontrados 19 artigos e incluídos 12 artigos, sendo divididos em categorias temáticas: exercício aeróbico (6 artigos), exercício resistido (4), exercício aeróbico associado ao resistido (2). Entre os exercícios aeróbicos, três artigos evidenciaram redução na pressão arterial sistólica (PAS) e pressão arterial diastólica (PAD). Três artigos afirmam que treinamento resistido reduz significativamente os valores de PAS em repouso e pressão arterial média (PAM), apenas um artigo não registrou uma redução significativa na PAD e frequência cardíaca (FC) de repouso. A utilização dos exercícios aeróbicos associados aos resistidos foram superiores aos demais, pois apontaram reduções significativas na PAS, PAD, PAM e FC de repouso, confirmando as recomendações da VI Diretriz Brasileira de Hipertensão Arterial, mas os estudos em idosos são escassos. CONCLUSÃO: Esta revisão confirma os benefícios oriundos da prática do exercício físico na redução da PA após o exercício em idosos hipertensos.

Glutathione enhances endothelium-mediated control of coronary vascular resistance via a ROS- and NO intermediate-dependent mechanism

The purpose of this investigation was to determine the effects of acute physiological GSH administration on endothelium-mediated reduction in coronary vascular resistance (CVR) using isolated perfused Sprague-Dawley rat hearts. A dose-response curve to GSH was conducted to determine a threshold concentration of GSH. We demonstrate that 30 μM GSH was sufficient to reduce CVR, and maximal dilation was achieved with 1 mM. In subsequent experiments, GSH was administered at concentrations of 0 [control (CON)], 1 μM, or 10 μM (GSH10), and dose-response curves to the endothelial agonist bradykinin (BK) were constructed. These GSH concentrations were chosen because of the physiological relevance and because the effects of GSH on BK action could be assessed independent of baseline differences in CVR. Sensitivity to BK (EC50) was enhanced in GSH10 vs. CON ( P < 0.05). This enhancement remained in the presence of nitric oxide (NO) synthase inhibition l-ωnitro-l-arginine (lNAME) and/or soluble guanylate cyclase (sGC) inhibition. Treatment with 4-hydroxy (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPOL) enhanced the sensitivity to BK in CON, similar to the effects of GSH10 and GSH10 + TEMPOL. However, the GSH10-dependent enhancement of EC50 observed in the presence of lNAME did not occur in the presence of lNAME + TEMPOL or in the presence of lNAME + sGC inhibition and NO scavenging. Collectively, these results suggest that GSH enhances BK-mediated dilation and reduction in CVR through an antioxidant-dependent mechanism that involves a NO intermediate but is unrelated to acute production of NO and GC-dependent effects of NO. These results suggest a mechanism whereby physiologically relevant levels of GSH modulate the endogenous reactive oxygen species and NO control of endothelium-dependent coronary vascular function.

Fish oil and vascular endothelial protection: bench to bedside

Fish oil is recommended for the management of hypertriglyceridemia and to prevent secondary cardiovascular disorders. Fish oil is a major source of ω-3-polyunsaturated fatty acids (PUFAs) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Clinical studies suggest that fish oil not only prevents the incidence of detrimental cardiovascular events, but also lowers the cardiovascular mortality rate. In addition to a classic lipid-lowering action, ω-3-PUFAs in fish oil could regulate blood pressure and enhance vascular integrity and compliance. Additionally, ω-3-PUFAs have the ability to protect vascular endothelial cells by decreasing oxidative stress, halting atherosclerotic events, and preventing vascular inflammatory and adhesion cascades. Intriguingly, recent studies have demonstrated that ω-3-PUFAs improve the function of vascular endothelium by enhancing the generation and bioavailability of endothelium-derived relaxing factor (nitric oxide) through upregulation and activation of endothelial nitric oxide synthase (eNOS). This certainly opens up a new area of research identifying potential mechanisms influencing fish oil-mediated functional regulatory action on vascular endothelium. We address in this review the potential of fish oil to prevent vascular endothelial dysfunction and associated cardiovascular disorders. Moreover, the mechanisms pertaining to fish oil-mediated eNOS activation and nitric oxide generation in improving endothelial function are delineated. We finally suggest the importance of further studies to determine the dose adjustment of fish oil with an optimal ratio of EPA and DHA for achieving consistent cardiovascular protection.

Effects of glutathione-depleting drug buthionine sulfoximine and aging on activity of endothelium-derived relaxing and contracting factors in carotid artery of Sprague-Dawley rats

The role of the antioxidant glutathione (GSH) in mediating endothelial (dys)function, and how that role may depend on age, is unclear. The main purpose of the current study was to investigate the effect of 10-day treatment with the GSH-depleting drug l-buthionine sulfoximine (BSO) on endothelium-derived relaxing factor and endothelium-derived contracting factor activities in the isolated common carotid artery (CCA) of Adult and Aging animals. CCA blood pressure and flow were unaffected by age or BSO. Endothelium-derived relaxing factor activity, examined in precontracted CCA as relaxation to cumulative acetylcholine (ACh), was largely nitric oxide synthase (NOS) mediated and was not different between Adult and Aging animals at lower ACh; however, at higher ACh, relaxation was blunted in Aging CCA, an effect abolished by cyclooxygenase (COX) inhibition but not by NOS inhibition nor by the reactive oxygen species (ROS) inhibitors 4-hydroxy-TEMPO or Mn(III)tetrakis(1-methyl-4-pyridyl)porphyrin,tetratosylate,hydroxide. Specific examination of endothelium-derived contracting factor activity in quiescent NOS-inhibited CCA established that higher ACh elicited a contractile response, ∼3.5-fold greater in Aging versus Adult CCA, which was abolished by COX-1-specific inhibition but unaffected by ROS inhibitors. Aging was unrelated to changes in liver or vascular tissue GSH or ROS content. BSO was effective in significantly decreasing GSH and increasing ROS content in both animal cohorts. However, NOS-mediated endothelium-derived relaxing factor activity was well preserved and age-related COX-mediated endothelium-derived contracting factor activity was unaffected in response to these BSO-induced perturbations, as were exogenous H2O2-stimulated NOS/non-NOS-mediated relaxation and COX-mediated contractile activities. These data suggest that, regardless of age, chronic partial depletion of GSH in vivo does not necessarily cause endothelium-dependent vasomotor dysfunction.

Far-infrared therapy induces the nuclear translocation of PLZF which inhibits VEGF-induced proliferation in human umbilical vein endothelial cells

Many studies suggest that far-infrared (FIR) therapy can reduce the frequency of some vascular-related diseases. The non-thermal effect of FIR was recently found to play a role in the long-term protective effect on vascular function, but its molecular mechanism is still unknown. In the present study, we evaluated the biological effect of FIR on vascular endothelial growth factor (VEGF)-induced proliferation in human umbilical vein endothelial cells (HUVECs). We found that FIR ranging 3∼10 µm significantly inhibited VEGF-induced proliferation in HUVECs. According to intensity and time course analyses, the inhibitory effect of FIR peaked at an effective intensity of 0.13 mW/cm² at 30 min. On the other hand, a thermal effect did not inhibit VEGF-induced proliferation in HUVECs. FIR exposure also inhibited the VEGF-induced phosphorylation of extracellular signal-regulated kinases in HUVECs. FIR exposure further induced the phosphorylation of endothelial nitric oxide (NO) synthase (eNOS) and NO generation in VEGF-treated HUVECs. Both VEGF-induced NO and reactive oxygen species generation was involved in the inhibitory effect of FIR. Nitrotyrosine formation significantly increased in HUVECs treated with VEGF and FIR together. Inhibition of phosphoinositide 3-kinase (PI3K) by wortmannin abolished the FIR-induced phosphorylation of eNOS and Akt in HUVECs. FIR exposure upregulated the expression of PI3K p85 at the transcriptional level. We further found that FIR exposure induced the nuclear translocation of promyelocytic leukemia zinc finger protein (PLZF) in HUVECs. This induction was independent of a thermal effect. The small interfering RNA transfection of PLZF blocked FIR-increased PI3K levels and the inhibitory effect of FIR. These data suggest that FIR induces the nuclear translocation of PLZF which inhibits VEGF-induced proliferation in HUVECs.

Exercise training enhances autonomic function after acute myocardial infarction: a randomized controlled study

INTRODUCTION

Heart rate recovery, defined as the fall in heart rate during the first minute after exercise, is an indicator of autonomic function, and has been found to be an independent predictor of mortality after acute myocardial infarction. Exercise training has several well-known benefits in terms of cardiorespiratory fitness, modifiable cardiovascular risk factors and prognosis after acute coronary events. However, there are no randomized controlled studies in the literature evaluating the effects of exercise training per se, controlling for changes in medication and diet, on heart rate recovery. Thus, this study aims to assess the effects of exercise training on autonomic function in coronary artery disease patients recovering from acute myocardial infarction.

METHODS

Thirty-eight patients following a first acute myocardial infarction participated in this prospective randomized clinical trial. Patients were randomized into two groups: exercise training or control. The exercise group participated in an 8-week aerobic exercise program, while the control received standard medical care and follow-up. Changes in hemodynamics at rest and at peak exercise (heart rate, systolic and diastolic blood pressure, and rate pressure product), dietary intake, cardiorespiratory fitness, and heart rate recovery were assessed.

RESULTS

Medication and diet remained unchanged in both groups during the study period. The exercise-training group improved resting hemodynamics, particularly resting heart rate (from 68.0 ± 9.2 to 62.6 ± 8.7 bpm, p=0.030) and systolic blood pressure (from 135 ± 7.1 to 125.6 ± 11.3 mm Hg, p=0.012), cardiorespiratory fitness (from 30.8 ± 7.8 to 33.9 ± 8.3 ml/min/kg, p=0.016), and heart rate recovery (from 20 ± 6 to 24 ± 5 bpm, p=0.007). No significant changes were observed in the control group.

CONCLUSIONS

Exercise training improved autonomic function, assessed by heart rate recovery, resting heart rate and systolic blood pressure, in the absence of changes in diet or medication.

The forgotten face of regular physical exercise: a 'natural' anti-atherogenic activity

Humans are not programmed to be inactive. The combination of both accelerated sedentary lifestyle and constant food availability disturbs ancient metabolic processes leading to excessive storage of energy in tissue, dyslipidaemia and insulin resistance. As a consequence, the prevalence of Type 2 diabetes, obesity and the metabolic syndrome has increased significantly over the last 30 years. A low level of physical activity and decreased daily energy expenditure contribute to the increased risk of cardiovascular morbidity and mortality following atherosclerotic vascular damage. Physical inactivity leads to the accumulation of visceral fat and consequently the activation of the oxidative stress/inflammation cascade, which promotes the development of atherosclerosis. Considering physical activity as a 'natural' programmed state, it is assumed that it possesses atheroprotective properties. Exercise prevents plaque development and induces the regression of coronary stenosis. Furthermore, experimental studies have revealed that exercise prevents the conversion of plaques into a vulnerable phenotype, thus preventing the appearance of fatal lesions. Exercise promotes atheroprotection possibly by reducing or preventing oxidative stress and inflammation through at least two distinct pathways. Exercise, through laminar shear stress activation, down-regulates endothelial AT1R (angiotensin II type 1 receptor) expression, leading to decreases in NADPH oxidase activity and superoxide anion production, which in turn decreases ROS (reactive oxygen species) generation, and preserves endothelial NO bioavailability and its protective anti-atherogenic effects. Contracting skeletal muscle now emerges as a new organ that releases anti-inflammatory cytokines, such as IL-6 (interleukin-6). IL-6 inhibits TNF-α (tumour necrosis factor-α) production in adipose tissue and macrophages. The down-regulation of TNF-α induced by skeletal-muscle-derived IL-6 may also participate in mediating the atheroprotective effect of physical activity.

The antihypertensive effect of ethyl acetate extract from red raspberry fruit in hypertensive rats

OBJECTIVES

To evaluate the antihypertensive effect of Xinjiang red raspberry fruit ethyl acetate extract (EER) on spontaneously hypertensive rats (SHR) and its possible mechanism from antioxidant perspective.

MATERIALS AND METHODS

The SHR rats were randomly divided into 3 groups, and treated with EER low dose (EERL, 100 mg/kg/d), high dose (EERH, 200 mg/kg/d), and water (SHR) through gastric gavage daily for 5 weeks. Another 8 age-matched male Wistar-Kyoto rats were used as normotensive group (WKY). The systolic blood pressure (SBP) was measured by noninvasive tail-cuff method once a week. At the end of the treatment, blood samples were collected and serum concentrations of nitric oxide (NO), superoxide dismutase (SOD), malondialchehyche (MDA), and plasma endothelin (ET) were determined.

RESULTS

Treatment of SHR rats with EER lowered the blood pressure compared with that treated with water (SHR), and the high dose showed more significant reduction in blood pressure. Treatment of SHR rats with EER increased serum NO and SOD levels and lowered ET and MDA levels. As compared with control group, NO levels were increased significantly in EERL (P < 0.01), SOD was elevated more significantly in both EERL and EERH (P < 0.01); MDA was decreased significantly in EERH group (P < 0.05), whereas plasma ET decreased more significantly in the EERH group (P < 0.05).

CONCLUSIONS

The red raspberry extracts demonstrated a dose-dependent antihypertensive effects in SHR and this may be related to increased NO activation and improved vascular endothelial dysfunction via antioxidation. These results confirmed that raspberries rich in polyphenols have potential cardiovascular protective effects.

Role and benefits of exercise in the management of patients with heart failure

Initial research established the feasibility of exercise training in patients with heart failure, as well as associated physiological benefits. This review summarizes the findings from over two dozen single-site studies that address the effect of exercise training on exercise capacity and cardiovascular and peripheral function. In addition, it incorporates the results from two meta-analyses and a recently completed multi-center trial, all of which studied the effects of exercise training on clinical outcomes. The major conclusions from these studies are that exercise training is safe; improves health status and exercise capacity; helps attenuate much of the abnormal pathophysiology that develops with heart failure; and yields a modest reduction in clinical events. The magnitude of the clinical benefits appears related to the volume of exercise completed. Future research is needed to identify which patient subgroups might benefit the most from exercise training, the optimal exercise dose or load needed to lessen disease-related symptoms and maximize clinical benefit, and the effects of exercise training in patients with heart failure and preserved left ventricular systolic function.

Endothelial ischemia-reperfusion injury in humans: association with age and habitual exercise

Advancing age is a major risk factor for coronary artery disease. Endothelial dysfunction accompanied by increased oxidative stress and inflammation with aging may predispose older arteries to greater ischemia-reperfusion (I/R) injury. Because coronary artery ischemia cannot be induced safely, the effects of age and habitual endurance exercise on endothelial I/R injury have not been determined in humans. Using the brachial artery as a surrogate model of the coronary arteries, endothelial function, assessed by brachial artery flow-mediated dilation (FMD), was measured before and after 20 min of continuous forearm occlusion in young sedentary (n = 10, 24 ± 2 yr) and middle-aged (n = 9, 48 ± 2 yr) sedentary adults to gain insight into the effects of primary aging on endothelial I/R injury. Young (n = 9, 25 ± 1 yr) and middle-aged endurance-trained (n = 9, 50 ± 2 yr) adults were also studied to determine whether habitual exercise provides protection from I/R injury. Fifteen minutes after ischemic injury, FMD decreased significantly by 37% in young sedentary, 35% in young endurance-trained, 68% in middle-aged sedentary, and 50% in middle-aged endurance-trained subjects. FMD returned to baseline levels within 30 min in young sedentary and endurance-trained subjects but remained depressed in middle-aged sedentary and endurance-trained subjects. Circulating markers of antioxidant capacity and inflammation were not related to FMD. In conclusion, advancing age is associated with a greater magnitude and delayed recovery from endothelial I/R injury in humans. Habitual endurance exercise may provide partial protection to the endothelium against this form of I/R injury with advancing age.