Cardiovascular risk factors as determinants of endothelium-dependent and endothelium-independent vascular reactivity in the general population

Sirtuin 1 and Vascular Function in Healthy Women and Men: A Randomized Clinical Trial Comparing the Effects of Energy Restriction and Resveratrol

Background: Sirtuin 1 (SIRT1) has been associated with longevity and protection against cardiometabolic diseases, but little is known about how it influences human vascular function. Therefore, this study evaluated the effects of SIRT1 activation by resveratrol and energy restriction on vascular reactivity in adults. Methods: A randomized trial allocated 48 healthy adults (24 women and 24 men), aged 55 to 65 years, to resveratrol supplementation or energy restriction for 30 days. Blood lipids, glucose, insulin, C-reactive protein, noradrenaline, SIRT1 (circulating and gene expression), and flow-mediated vasodilation (FMD) and nitrate-mediated vasodilation (NMD) were measured. Results: Both interventions increased circulating SIRT1 (p < 0.001). Pre- and post-tests changes of plasma noradrenaline were significant for both groups (resveratrol: p = 0.037; energy restriction: p = 0.008). Baseline circulating SIRT1 was inversely correlated with noradrenaline (r = -0.508; p < 0.01), and post-treatment circulating SIRT1 was correlated with NMD (r = 0.433; p < 0.01). Circulating SIRT1 was a predictor of FMD in men (p = 0.045), but not in women. SIRT1 was an independent predictor of NMD (p = 0.026) only in the energy restriction group. Conclusions: Energy restriction and resveratrol increased circulating SIRT1 and reduced sympathetic activity similarly in healthy adults. SIRT1 was independently associated with NMD only in the energy restriction group.

Effectiveness of the influenza vaccine at reducing adverse events in patients with heart failure: A systematic review and meta-analysis

BACKGROUND

The association between influenza and adverse vascular events in patients with heart failure is well documented. The effect of the influenza vaccine on preventing such adverse events is uncertain. This systematic review and meta-analysis addressed whether vaccination against influenza reduces adverse vascular events and mortality in heart failure patients.

METHODS

MEDLINE and EMBASE databases were comprehensively searched, study screening and quality assessment were completed, and data was synthesized. Eligible studies investigated heart failure patients who received the influenza vaccine, and reported outcomes within 12 months, compared to heart failure patients who did not receive the influenza vaccine. The following 6 outcomes were assessed: all-cause mortality, cardiovascular-related mortality, all-cause hospitalization, cardiovascular-related hospitalization, non-fatal myocardial infarction, and non-fatal stroke. Risk of bias was assessed using the Newcastle-Ottawa Scale and a GRADE assessment was completed. A random-effects meta-analysis was performed to estimate the pooled risk ratio (RR), 95% confidence intervals (CIs), and heterogeneity using I² statistics.

RESULTS

After synthesizing data from 7 non-randomized studies (247,842 patients), the results demonstrate the risk of all-cause mortality is significantly reduced within 12 months of a heart failure patient receiving the influenza vaccine (RR = 0.75, 95% CI 0.71-0.79; P<0.0001); very low certainty of evidence. The risk of cardiovascular-related mortality was significantly reduced (RR = 0.77, 95% CI 0.73-0.81; P<0.0001); low certainty of evidence. The pooled risk of all-cause hospitalization was higher among vaccinated heart failure patients (RR = 1.24, 95% CI 1.13-1.35; P<0.0001), based on two studies; very low certainty of evidence and considerable heterogeneity (I² = 90%). No eligible studies assessed cardiovascular-related hospitalization, non-fatal myocardial infarction, or non-fatal stroke.

CONCLUSIONS

Influenza vaccination appears to reduce adverse cardiovascular events, although the certainty of the evidence is low or very low. Rigorous randomized controlled trial evidence is needed to further examine the protective effect of the influenza vaccine in heart failure patients.

Regular transient limb ischemia protects endothelial function against hypercholesterolemic damage in rabbits

Regular transient limb ischemia (RTLI) can prevent atherosclerosis in hypercholesterolemic rabbits. As endothelial dysfunction is the initial factor leading to atherosclerosis, we investigated the effect of RTLI on endothelial function in hypercholesterolemic rabbits. We randomly allocated 15 New Zealand white rabbits to three groups, five animals per group: the hypercholesterolemic group (Group H), the sham RTLI group (Group S), and the RTLI group (Group L). All rabbits received hypercholesterolemic fodder daily. No intervention was performed on the rabbits in Group H. Rabbits in Group S were kept in hutches, with a deflated cuff applied to their left hind limb for 60 min every day. For rabbits in Group L, RTLI (six cycles of 5-min ischemia and 5-min reperfusion of the left hind limb) was applied once daily for 12 weeks. At the end of week 12, a segment of the abdominal aorta was isolated from each rabbit for in vitro measurement of the endothelium-dependent vasodilation (EDV) response to different concentrations of acetylcholine and the endothelium-independent vasodilation (EIV) response to sodium nitroprusside. The EDV response was significantly higher in Group L than in Groups S and H (p < 0.05), with no significant difference between Groups S and H (p > 0.05). There was no difference in the EIV response among the three groups. RTLI could improve the EDV response, protecting endothelial function against hypercholesterolemic damage.

Comparison of Resveratrol Supplementation and Energy Restriction Effects on Sympathetic Nervous System Activity and Vascular Reactivity: A Randomized Clinical Trial

Background: Chronic sympathetic nervous system activation is associated with endothelial dysfunction and cardiometabolic disease, which may be modulated by resveratrol (RSV) and energy restriction (ER). This study aimed to examine the effects of RSV and ER on plasma noradrenaline (NA), flow-mediated vasodilation (ed-FMD), and endothelium-independent nitrate-mediated vasodilation (ei-NMD). Methods: The study included 48 healthy adults randomized to 30-days intervention of RSV or ER. Results: Waist circumference, total cholesterol, HDL-c, LDL-c, apoA-I, and plasma NA decreased in the ER group, whilst RSV increased apoB and total cholesterol, without changing plasma NA. No effects on vascular reactivity were observed in both groups. Plasma NA change was positively correlated with total cholesterol (r = 0.443; p = 0.002), triglycerides (r = 0.438; p = 0.002), apoA-I (r = 0.467; p = 0.001), apoB (r = 0.318; p = 0.032) changes, and ei-NMD (OR = 1.294; 95%CI: 1.021–1.640). Conclusions: RSV does not improve cardiometabolic risk factors, sympathetic activity, and endothelial function. ER decreases plasma NA and waist circumference as well as improves blood lipids, but does not modify endothelial function. Finally, plasma NA was associated with ei-NMD, which could be attributed to a higher response to nitrate in patients with greater resting sympathetic vasoconstriction.

Individual variation of follicular phase changes in endothelial function across two menstrual cycles

NEW FINDINGS

What is the central question of this study? The purpose of this study was to determine intra-individual reproducibility of follicular phase changes in endothelial function (flow-mediated dilatation) over two menstrual cycles in healthy, premenopausal women. What is the main finding and its importance? Phase changes in endothelial function were not consistent at the individual level across two menstrual cycles, which challenges the utility of interpreting individual responses over one cycle.

ABSTRACT

Evidence regarding the impact of menstrual phase on endothelial function is conflicting, and studies to date have examined responses only over a single cycle. It is unknown whether the observed inter-individual variability of phase changes in endothelial function reflects stable, inter-individual differences in responses to oestrogen (E₂ ; a primary female sex hormone). The purpose of this study was to examine changes in endothelial function from the early follicular (EF; low-E₂ ) phase to the late follicular (LF; high-E₂ ) phase over two consecutive cycles. Fourteen healthy, regularly menstruating women [22 ± 3 years of age (mean ± SD)] participated in four visits (EF_Visit 1 , LF_Visit 2 , EF_Visit 3 and LF_Visit 4 ) over two cycles. Ovulation testing was used to determine the time between the LF visit and ovulation. During each visit, endothelial function [brachial artery flow-mediated dilatation (FMD)], E₂ and progesterone were assessed. At the group level, there was no impact of phase or cycle on FMD (P = 0.48 and P = 0.65, respectively). The phase change in FMD in cycle 1 did not predict the phase change in cycle 2 (r = 0.03, P = 0.92). Using threshold-based classification (2 × typical error threshold), four of 14 participants (29%) exhibited directionally consistent phase changes in FMD across cycles. Oestrogen was not correlated between cycles, and this might have contributed to variability in the FMD response. The intra-individual variability in follicular fluctuation in FMD between menstrual cycles challenges the utility of interpreting individual responses to phase over a single menstrual cycle.

Effects of Influenza Vaccine on Mortality and Cardiovascular Outcomes in Patients With Cardiovascular Disease: A Systematic Review and Meta-Analysis

Background

Influenza infection causes considerable morbidity and mortality in patients with cardiovascular disease. We assessed the effects of the influenza vaccine on mortality and cardiovascular outcomes in patients with cardiovascular disease.

Methods and Results

We searched PubMed, Embase, and the Cochrane Library through January 2020 for randomized controlled trials and observational studies assessing the effects of influenza vaccine on mortality and cardiovascular outcomes in patients with cardiovascular disease. Estimates were reported as random effects risk ratios (RRs) with 95% CIs. Analyses were stratified by study design into randomized controlled trials and observational studies. A total of 16 studies (n=237 058), including 4 randomized controlled trials (n=1667) and 12 observational studies (n=235 391), were identified. Participants' mean age was 69.2±7.01 years, 36.6% were women, 65.1% had hypertension, 31.1% had diabetes mellitus, and 23.4% were smokers. At a median follow‐up duration of 19.5 months, influenza vaccine was associated with a lower risk of all‐cause mortality (RR, 0.75; 95% CI, 0.60–0.93 [P=0.01]), cardiovascular mortality (RR, 0.82; 95% CI, 0.80–0.84 [P<0.001]), and major adverse cardiovascular events (RR, 0.87; 95% CI, 0.80–0.94 [P<0.001]) compared with control. The use of the influenza vaccine was not associated with a statistically significant reduction of myocardial infarction (RR, 0.73; 95% CI, 0.49–1.09 [P=0.12]) compared with control.

Conclusions

Data from both randomized controlled trials and observational studies support the use of the influenza vaccine in adults with cardiovascular disease to reduce mortality and cardiovascular events, as currently supported by clinical guidelines. Clinicians and health systems should continue to promote the influenza vaccine as part of comprehensive secondary prevention.

Randomized controlled trial of influenza vaccine in patients with heart failure to reduce adverse vascular events (IVVE): Rationale and design

Background

Influenza is associated with an increase in the risk of cardiac and other vascular events. Observational data and small randomized trials suggest that influenza vaccination may reduce such adverse vascular events.

Research Design and Methods

In a randomized controlled trial patients with heart failure are randomized to receive either inactivated influenza vaccine or placebo annually for 3 years. Patients aged ≥18 years with a clinical diagnosis of heart failure and NYHA functional class II, III and IV are eligible. Five thousand patients from 10 countries where influenza vaccination is not common (Asia, the Middle East, and Africa) have been enrolled. The primary outcome is a composite of the following: cardiovascular death, non-fatal myocardial infarction, non-fatal stroke and hospitalizations for heart failure using standardized criteria. Analyses will be based on comparing event rates between influenza vaccine and control groups and will include time to event, rate comparisons using Poisson methods, and logistic regression. The analysis will be conducted by intention to treat i.e. patients will be analyzed in the group in which they were assigned. Multivariable secondary analyses to assess whether variables such as age, sex, seasonality modify the benefits of vaccination are also planned for the primary outcome.

Conclusion

This is the largest randomized trial to test if influenza vaccine compared to control reduces adverse vascular events in high risk individuals.

Trial registration number

Clinicaltrials.govNCT02762851

Correlation of endothelial dysfunction measured by flow-mediated vasodilatation to severity of coronary artery disease

OBJECTIVES

Brachial artery ultrasound imaging during reactive hyperemia is widely used tool for quantifying endothelium dependent vasomotion. Angiodefender device is used for non invasive determination of percentage flow mediated vasodilation (FMD). An attempt is made to study whether endothelial dysfunction determined by FMD of brachial artery predicts the presence or absence of coronary artery disease and its correlation with the severity of coronary artery disease.

METHODS

One hundred six patients admitted between May 2014 and April 2015 who were posted for coronary angiography diagnosed to have chronic stable angina on clinical basis and/or by exercise stress test, for evaluation of coronary artery disease were submitted to standard clinical evaluation, calculation of percentage FMD by Angiodefender device. Statistical significance of difference of categorical variables was tested using Fisher's exact test. Sensitivity, specificity, positive predictive value and negative predictive value of FMD were studied.

RESULTS

There was no correlation between number of risk factors and percentage of FMD. Significantly higher proportion of cases with less FMD had higher prevalence of coronary artery disease and vice-versa. Significantly higher proportion of cases with positive stress test had less percentage of FMD and vice-versa. Significantly higher proportion of cases with less percentage of FMD and positive stress test had higher prevalence of obstructive coronary artery disease and vice-versa. Specificity was 100% when percentage of FMD was ≤10.

CONCLUSIONS

FMD an inexpensive and non-invasive test provides information regarding extent and severity of coronary artery disease.

Heart Failure with Preserved Ejection Fraction and Future Pharmacological Strategies: a Glance in the Crystal Ball

PURPOSE OF REVIEW

The current definition of heart failure is mainly based on an inappropriate measure of cardiac function, i.e., left ventricular ejection fraction (LVEF). The initial sole entity, heart failure with reduced ejection fraction (HFrEF, LVEF <40%), was complemented by the addition of heart failure with preserved ejection fraction (HFpEF, LVEF ≥50%) and most recently, heart failure with mid-range ejection fraction (HFmrEF, LVEF 40-49%). Initially, HFpEF was believed to be a purely left ventricular diastolic dysfunction. Pathophysiological concepts of HFpEF have changed considerably during the last years. In addition to intrinsic cardiac mechanisms, the heart failure pathogenesis is increasingly considered as driven by non-cardiac systemic processes including metabolic disorders, ischemic conditions, and pro-inflammatory/pro-fibrotic or immunological alterations. Presentation and pathophysiology of HFpEF is heterogeneous, and its management remains a challenge since evidence of therapeutic benefits is scarce. Up to now, there are no therapies improving survival in patients with HFpEF.

RECENT FINDINGS

Several results from clinical and preclinical interventions targeting non-cardiac mechanisms or non-pharmacological interventions including new anti-diabetic or anti-inflammatory drugs, mitochondrial-targeted anti-oxidants, anti-fibrotic strategies, microRNases incl. antagomirs, cell therapeutic options, and high-density lipoprotein-raising strategies are promising and under further investigation. This review addresses mechanisms and available data of current best clinical practice and novel approaches towards HFpEF.

Acetylcholine versus cold pressor testing for evaluation of coronary endothelial function

Background

Assessment of coronary endothelial function with intracoronary acetylcholine (IC-Ach) provides diagnostic and prognostic data in patients with suspected coronary microvascular dysfunction (CMD), but is often not feasible due in part to the time and expertise needed for pharmacologic mixing. Cold pressor testing (CPT) is a simple and safe stimulus useful for either invasive or non-invasive endothelial function testing and myocardial perfusion imaging but has not been specifically evaluated among symptomatic women with signs of ischemic heart disease (IHD) who have no obstructive coronary artery disease (CAD).

Methods

163 women with signs and symptoms of IHD and no obstructive CAD from the NHLBI- Women’s Ischemia Syndrome Evaluation-Coronary Vascular Dysfunction (WISE-CVD) study underwent coronary reactivity testing with a Doppler flow wire (FloWire^® Volcano, San Diego, CA) in the proximal left anterior descending artery. Coronary artery diameter and coronary blood flow (CBF) assessed by core lab using QCA before and after IC-Ach (18.2 μg/ml infused over 3 minutes) and during CPT.

Results

Mean age was 55 ± 12 years. Rate pressure product (RPP) in response to IC-Ach did not change (baseline to peak, P = 0.26), but increased during CPT (363±1457; P = 0.0028). CBF in response to CPT was poorly correlated to IC-Ach CBF. Change in coronary artery diameter after IC-Ach correlated with change after CPT (r = 0.59, P<0.001). The correlation coefficient was stronger in subjects with coronary dilation to IC-Ach (r = 0.628, P<0.001) versus those without dilation (r = 0.353, P = 0.002), suggesting that other factors may be important to this relationship when endothelium is abnormal.

Conclusions

In women with no obstructive CAD and suspected CMD, coronary diameter changes with IC-Ach and CPT are moderately-well correlated suggesting that CPT testing may be of some use, particularly among patients with normal endothelial function, however, not an alternative to IC-Ach for diagnosis of coronary endothelial dysfunction.

Genetic Regulation of Endothelial Vasomotor Function

The endothelium plays an important role in the regulation of vasomotor tone and the maintenance of vascular integrity. Endothelial dysfunction, i.e., impaired endothelial dependent dilation, is a fundamental component of the pathogenesis of cardiovascular disease. Although endothelial dysfunction is associated with a number of cardiovascular disease risk factors, those risk factors are not the only determinants of endothelial dysfunction. Despite knowing many molecules involved in endothelial signaling pathways, the genetic contribution to endothelial function has yet to be fully elucidated. This mini-review summarizes current evidence supporting the genetic contribution to endothelial vasomotor function. Findings from population-based studies, association studies for candidate genes, and unbiased large genomic scale studies in humans and rodent models are discussed. A brief synopsis of the current studies addressing the genetic regulation of endothelial responses to exercise training is also included.

Association of smoking status with health-related outcomes after percutaneous coronary intervention

BACKGROUND

Patients who smoke at the time of percutaneous coronary intervention (PCI) would ideally have a strong incentive to quit, but most do not. We sought to compare the health status outcomes of those who did and did not quit smoking after PCI with those who were not smoking before PCI.

METHODS AND RESULTS

A cohort of 2765 PCI patients from 10 US centers were categorized into never, past (smoked in the past but had quit before PCI), quitters (smoked at time of PCI but then quit), and persistent smokers. Health status was measured with the disease-specific Seattle Angina Questionnaire and the EuroQol 5 dimensions, adjusted for baseline characteristics. In unadjusted analyses, persistent smokers had worse disease-specific and overall health status when compared with other groups. In fully adjusted analyses, persistent smokers showed significantly worse health-related quality of life when compared with never smokers. Importantly, of those who smoked at the time of PCI, quitters had significantly better adjusted Seattle Angina Questionnaire angina frequency scores (mean difference, 2.73; 95% confidence interval, 0.13-5.33) and trends toward higher disease specific (Seattle Angina Questionnaire quality of life mean difference, 1.97; 95% confidence interval, -1.24 to 5.18), and overall (EuroQol 5 dimension visual analog scale scores mean difference, 2.45; 95% confidence interval, -0.58 to 5.49) quality of life when compared with persistent smokers at 12 months.

CONCLUSIONS

Smokers at the time of PCI have worse health status at 1 year than those who never smoked, whereas smokers who quit after PCI have less angina at 1 year than those who continue smoking.

Characterization of vascular disease risk in postmenopausal women and its association with cognitive performance

OBJECTIVES

While global measures of cardiovascular (CV) risk are used to guide prevention and treatment decisions, these estimates fail to account for the considerable interindividual variability in pre-clinical risk status. This study investigated heterogeneity in CV risk factor profiles and its association with demographic, genetic, and cognitive variables.

METHODS

A latent profile analysis was applied to data from 727 recently postmenopausal women enrolled in the Kronos Early Estrogen Prevention Study (KEEPS). Women were cognitively healthy, within three years of their last menstrual period, and free of current or past CV disease. Education level, apolipoprotein E ε4 allele (APOE4), ethnicity, and age were modeled as predictors of latent class membership. The association between class membership, characterizing CV risk profiles, and performance on five cognitive factors was examined. A supervised random forest algorithm with a 10-fold cross-validation estimator was used to test accuracy of CV risk classification.

RESULTS

The best-fitting model generated two distinct phenotypic classes of CV risk 62% of women were "low-risk" and 38% "high-risk". Women classified as low-risk outperformed high-risk women on language and mental flexibility tasks (p = 0.008) and a global measure of cognition (p = 0.029). Women with a college degree or above were more likely to be in the low-risk class (OR = 1.595, p = 0.044). Older age and a Hispanic ethnicity increased the probability of being at high-risk (OR = 1.140, p = 0.002; OR = 2.622, p = 0.012; respectively). The prevalence rate of APOE-ε4 was higher in the high-risk class compared with rates in the low-risk class.

CONCLUSION

Among recently menopausal women, significant heterogeneity in CV risk is associated with education level, age, ethnicity, and genetic indicators. The model-based latent classes were also associated with cognitive function. These differences may point to phenotypes for CV disease risk. Evaluating the evolution of phenotypes could in turn clarify preclinical disease, and screening and preventive strategies. ClinicalTrials.gov NCT00154180.

Cerebral and extracerebral vasoreactivity in symptomatic lacunar stroke patients: a case-control study

BACKGROUND

Whether cerebral artery endothelial dysfunction is a key factor of symptomatic lacunar stroke and cerebral small vessel disease remains unclear.

METHODS

Cerebral and extracerebral vasoreactivity were measured in 81 patients with recent symptomatic lacunar stroke and in 81 control subjects matched for main vascular risk factors. Cerebral vasoreactivity and carotid endothelial-dependent vasodilation were measured after five-minutes of carbon dioxide-induced hypercapnia. Brachial endothelial-dependent vasodilation was assessed after hyperemia induced by deflating a cuff around the forearm previously inflated to 200 mmHg for four-minutes. Carotid and brachial endothelial-independent vasodilation were measured five-minutes after administration of sublingual nitroglycerin 300 μg. Brain magnetic resonance imaging were analyzed in lacunar stroke patients.

RESULTS

One-month after stroke onset, patients had more severely impaired cerebral vasoreactivitys than matched controls (mean ± standard deviation, 14·4 ± 12·1% vs. 19·4 ± 17·4%; P = 0·049). Severe alterations of both carotid and brachial endothelial-dependent and at a lesser degree of carotid and brachial endothelial-independent vasodilation were observed in both groups. After adjustment for confounders, subjects with a cerebral vasoreactivity value in the two lower tertiles (≤19·6%) were more likely to have had a symptomatic lacunar stroke (adjusted odds ratio, 3·78; 95% confidence interval, 1·42 to 10·08; P = 0·008). Only alteration of brachial endothelial-independent vasodilation correlated with parenchymal abnormalities, namely microbleeds and leukoaraiosis.

CONCLUSIONS

While abnormalities in extracerebral vasoreactivity seem related to vascular risk factors, the severity of endothelial dysfunction in cerebral arteries may be determinant in the occurrence of symptomatic lacunar stroke in patients with small vessel disease.

Evolving concepts of the role of high-density lipoprotein in protection from atherosclerosis

High-density lipoprotein (HDL) is classified as a negative risk factor due to the inverse relationship between elevated levels of HDL cholesterol and atherosclerosis. The mechanism by which HDL can mediate protection from atherosclerosis is complex and multifactorial. The primary role of reverse cholesterol transport in the reduction of risk for coronary artery disease is supported by a considerable amount of experimental data. HDL is able to interact with and remove cholesterol from the lipid-laden foam cells in the peripheral vasculature with subsequent transportation to the liver for excretion. However, HDL has multiple other physiologic effects that may play a significant role in protection from atherosclerosis. HDL has been demonstrated to exhibit multiple beneficial effects on the coagulation system. Platelet function is improved by both direct and indirect mechanisms. HDL has a complex interaction with the protein C and protein S system. Thrombolytic balance is also improved by HDL. HDL has been demonstrated to have a significant natural antioxidant effect that inhibits the oxidative step required for low-density lipoprotein uptake by the macrophage. Additionally, HDL has also been demonstrated to exert multiple beneficial effects on endothelial function, including decreased apoptosis and endothelial repair.

Severe obesity is associated with impaired arterial smooth muscle function in young adults

The degree of arterial dilatation induced by exogenous nitrates (nitrate-mediated dilatation, NMD) has been similar in obese and normal-weight adults after single high-dose glyceryl trinitrate (GTN). We examined whether NMD is impaired in obesity by performing a GTN dose-response study, as this is a potentially more sensitive measure of arterial smooth muscle function. In this cross-sectional study, subjects were 19 obese (age 31.0 ± 1.2 years, 10 male, BMI 44.1 ± 2.1) and 19 age- and sex-matched normal-weight (BMI 22.4 ± 0.4) young adults. Blood pressure (BP), triglycerides, high-density lipoprotein (HDL), and low-density lipoprotein (LDL)-cholesterol, glucose, insulin, high-sensitivity C-reactive protein (hs-CRP), carotid intima-media thickness (CIMT), and flow-mediated dilatation (FMD) were measured. After incremental doses of GTN, brachial artery maximal percent dilatation (maximal NMD) and the area under the dose-response curve (NMD AUC) were calculated. Maximal NMD (13.4 ± 0.9% vs. 18.3 ± 1.1%, P = 0.002) and NMD AUC (54,316 ± 362 vs. 55,613 ± 375, P = 0.018) were lower in obese subjects. The obese had significantly higher hs-CRP, insulin, and CIMT and lower HDL-cholesterol. Significant bivariate associations existed between maximal NMD or NMD AUC and BMI-group (r = -0.492, P = 0.001 or r = -0.383, P = 0.009), hs-CRP (r = -0.419, P = 0.004 or r = -0.351, P = 0.015), and HDL-cholesterol (r = 0.374, P = 0.01 or r = 0.270, P = 0.05). On multivariate analysis, higher BMI-group remained as the only significant determinant of maximal NMD (r² = 0.242, β = -0.492, P = 0.002) and NMD AUC (r² = 0.147, β = -0.383, P = 0.023). In conclusion, arterial smooth muscle function is significantly impaired in the obese. This may be important in their increased cardiovascular risk.

The role of high-density lipoproteins in reducing the risk of vascular diseases, neurogenerative disorders, and cancer

High-density lipoprotein (HDL) is one of the major carriers of cholesterol in the blood. It attracts particular attention because, in contrast with other lipoproteins, as many physiological functions of HDL influence the cardiovascular system in favourable ways unless HDL is modified pathologically. The functions of HDL that have recently attracted attention include anti-inflammatory and anti-oxidant activities. High anti-oxidant and anti-inflammatory activities of HDL are associated with protection from cardiovascular disease. Atheroprotective activities, as well as a functional deficiency of HDL, ultimately depend on the protein and lipid composition of HDL. Further, numerous epidemiological studies have shown a protective association between HDL-cholesterol and cognitive impairment. Oxidative stress, including lipid peroxidation, has been shown to be the mediator of the pathologic effects of numerous risk factors of Alzheimer's disease. Lifestyle interventions proven to increase HDL- cholesterol levels including "healthy" diet, regular exercise, weight control, and smoking cessation have also been shown to provide neuro-protective effects. This review will focus on current knowledge of the beneficial effects of HDL-cholesterol as it relates to cardiovascular diseases, breast and lung cancers, non-Hodgkin's lymphoma, as well as its neuroprotective potential in reducing the risk of Alzheimer's disease and dementia.

Capillary pressure may predict preclinical changes in the eye

AIMS/HYPOTHESIS

Microvascular dysfunction is associated with end-organ damage. Macular oedema is an important component of diabetic retinopathy. Macular thickness can be accurately quantified by optical coherence tomography (OCT), enabling accurate assessment of the macular prior to clinically apparent abnormalities. We investigated whether macular (fovea) thickness in non-diabetic individuals is related to the microvascular variables controlling fluid filtration across a blood vessel wall, in particular capillary pressure and the microvascular filtration capacity (Kf).

METHODS

We recruited 50 non-diabetic individuals (25 men, 25 women; age range: 26-78 years; BMI range: 20-46 kg/m(2)). Fovea thickness was assessed by OCT. Microvascular assessments included: finger nailfold capillary pressure; Kf; microvascular structural assessments, i.e. skin vasodilatory capacity, minimum vascular resistance (MVR) and microvascular distensibility; and endothelial function.

RESULTS

At 214.6 (19.9) microm (mean [SD]), fovea thickness was within normal range. Capillary pressure, adjusted for BMI, was associated with fovea thickness (standardised beta 0.573, p = 0.006, linear regression). Fovea thickness was not associated with Kf, microvascular structural assessments or endothelial function. Capillary pressure was still associated with fovea thickness when adjusted for microvascular variables (Kf, vasodilatory capacity, MVR, microvascular distensibility or endothelial function), or for risk factors for diabetes (systemic blood pressure, insulin sensitivity, inflammation, glycaemic status and lipids) and age.

CONCLUSIONS/INTERPRETATION

Capillary pressure, a key determinant of movement of fluid across a blood vessel wall, is associated with fovea thickness in non-diabetic individuals. This suggests that with regard to potential preventative or therapeutic targets, attention should be directed at the mechanisms determining retinal microvascular pressure.

Coronary microvascular reactivity to adenosine predicts adverse outcome in women evaluated for suspected ischemia results from the National Heart, Lung and Blood Institute WISE (Women's Ischemia Syndrome Evaluation) study

OBJECTIVES

We investigated whether coronary microvascular dysfunction predicts major adverse outcomes during follow-up among women with signs and symptoms of ischemia.

BACKGROUND

Altered coronary reactivity occurs frequently in women evaluated for suspected ischemia, and the endothelium-dependent component is linked with adverse outcomes. Possible links between endothelium-independent microvascular coronary reactivity and adverse outcomes remain uncertain.

METHODS

As part of the National Heart, Lung and Blood Institute-sponsored WISE (Women's Ischemia Syndrome Evaluation), we investigated relationships between major adverse outcomes and baseline coronary flow reserve (CFR) after intracoronary adenosine in 189 women referred to evaluate suspected ischemia.

RESULTS

At a mean of 5.4 years, we observed significant associations between CFR and major adverse outcomes (death, nonfatal myocardial infarction, nonfatal stroke, or hospital stay for heart failure). An exploratory receiver-operator characteristic analysis identified CFR <2.32 as the best discriminating threshold for adverse outcomes (event rate 26.7%; and >or=2.32 event rate 12.2%; p = 0.01). Lower CFR was associated with increased risk for major adverse outcomes (hazard ratio: 1.16, 95% confidence interval: 1.04 to 1.30; p = 0.009). This held true among the 152 women without obstructive coronary artery disease (CAD) (hazard ratio: 1.20, 95% confidence interval: 1.05 to 1.38; p = 0.008). The CFR significantly improved prediction of adverse outcomes over angiographic CAD severity and other risk conditions.

CONCLUSIONS

Among women with suspected ischemia and atherosclerosis risk factors, coronary microvascular reactivity to adenosine significantly improves prediction of major adverse outcomes over angiographic CAD severity and CAD risk factors. These findings suggest that coronary microvessels represent novel targets for diagnostic and therapeutic strategies to predict and limit adverse outcomes in women. (Women's Ischemia Syndrome Evaluation [WISE]; NCT00000554).

Green tea (Camellia sinensis) catechins and vascular function

The health benefits of green tea (Camellia sinensis) catechins are becoming increasingly recognised. Amongst the proposed benefits are the maintenance of endothelial function and vascular homeostasis and an associated reduction in atherogenesis and CVD risk. The mounting evidence for the influential effect of green tea catechins on vascular function from epidemiological, human intervention and animal studies is subject to review together with exploration of the potential mechanistic pathways involved. Epigallocatechin-3-gallate, one of the most abundant and widely studied catechin found in green tea, will be prominent in the present review. Since there is a substantial inconsistency in the published data with regards to the impact of green tea catechins on vascular function, evaluation and interpretation of the inter- and intra-study variability is included. In conclusion, a positive effect of green tea catechins on vascular function is becoming apparent. Further studies in animal and cell models using physiological concentrations of catechins and their metabolites are warranted in order to gain some insight into the physiology and molecular basis of the observed beneficial effects.

Posterior reversible encephalopathy syndrome and cerebral vasculopathy associated with influenza A infection: report of a case and review of the literature

BACKGROUND AND PURPOSE

Influenza A infection can precipitate encephalopathy, encephalitis, or Reye syndrome with the development of cerebral edema in children and is associated with an increased incidence of stroke in adults. The mechanism of these events is poorly understood. Posterior reversible encephalopathy syndrome (PRES) is seen in association with infection/sepsis, and cerebral vasculopathy has been demonstrated in PRES. We describe a case of PRES that develops in association with influenza A.

SUMMARY OF CASE

A normotensive 65-year-old woman presented with altered mentation and nausea in the setting of a viral prodromal illness ultimately confirmed as influenza A. Posterior reversible encephalopathy syndrome developed on the second day after admission. Catheter cerebral angiogram documented vasculopathy in PRES-involved regions with areas of focal vessel dilatation and string-of-bead appearance.

CONCLUSIONS

The association between influenza A and PRES with documentation of cerebral vasculopathy suggests a common systemic vascular mechanism behind PRES and influenza-related encephalopathic edema and stroke.

Rapeseed protein in a high-fat mixed meal alleviates postprandial systemic and vascular oxidative stress and prevents vascular endothelial dysfunction in healthy rats

High-saturated fat and high-sucrose meals induce vascular endothelial dysfunction, the early hallmark of atherogenesis. The impact of dietary protein on vascular homeostasis remains misunderstood. In this study, we investigated whether rapeseed protein, an emergent arginine- and cysteine-rich protein, can acutely modulate the onset of adverse effects induced by a high-saturated fat meal (HFM). In a series of crossover experiments, healthy rats received 3 HFM (saturated fat: 60%; sucrose: 20%; protein: 20% energy) with the protein source being either total milk protein (MP; control), rapeseed protein (RP), or MP supplemented with cysteine and arginine to the same level as in RP (MP+AA). Endothelium-related vascular reactivity, measured as an acetylcholine-induced transient decrease in blood pressure, and plasma triglycerides, hydroperoxides, cyclic GMP (cGMP), and free 3-nitrotyrosine were measured before and 2, 4, and 6 h after meals. Superoxide anion production, expressed as ethidine fluorescence, was measured in the aorta 6 h after meals. Whereas plasma triglycerides rose similarly in all meals, the decrease in vascular reactivity after MP was attenuated after MP+AA and entirely prevented after RP. The type of meal had no consistent effect on plasma cGMP and free 3-nitrotyrosine over the postprandial period. The postprandial increase in plasma hydroperoxides differed according to the meal, and concentrations were 43% lower 6 h after MP+AA and RP than after MP. Aortic superoxide anion production was 36% lower 6 h after RP than MP. These results show that substituting rapeseed protein for milk protein markedly reduces vascular and oxidative disturbances induced by an HFM and this may be mediated in part by cysteine and arginine.

[Inflammation and C-reactive protein in cardiovascular disease]

BACKGROUND

This article reviews the role of inflammation in development of atherosclerosis and associated complications and discusses use of the inflammatory marker - high-sensitivity C-reactive protein (hs-CRP) - in risk stratification.

MATERIAL AND METHODS

The article is based on selected publications retrieved from a non-systematic search of PubMed and the authors' experience within the field.

RESULTS

Both chronic inflammatory disease and acute infections are associated with an increased risk of cardiovascular events. Influenza vaccination reduces the risk of coronary ischaemic events in patients with coronary artery disease, but the effect on cardiovascular mortality is not documented. Hs-CRP is an independent predictor of cardiovascular events in populations with and without established cardiovascular disease. Treatment with Rosuvastatin led to decreased hs-CRP-levels and a reduced risk for cardiovascular events in subjects without known cardiovascular disease, with normal serum cholesterol and hs-CRP-levels above 2 mg/l.

INTERPRETATION

Individuals with chronic inflammatory disease and those with high risk and acute infection are at risk for cardiovascular events and should be evaluated for primary prevention. In patient groups at moderate risk for cardiovascular disease, hs-CRP can be a valuable supplement to established factors for risk stratification. Despite numerous studies confirming hs-CRP's role as an independent risk marker, hs-CRP has not found its place in international guidelines. This should be reconsidered on the background of new study results.

Inflammation and oxidative stress are associated differently with endothelial function and arterial stiffness in healthy subjects and in patients with atherosclerosis

Inflammation and oxidative stress (OxS) play key roles in atherogenesis; however, their causal relationship is not yet completely understood. Much attention has been given to the possibility that inflammation is a primary process of atherosclerosis and that OxS may be a by-product of the inflammatory process. We hypothesized, accordingly, that chronic systemic inflammation affects endothelial vasomotor function in the subclinical condition, whereas oxidative modifications are more involved in the structural stiffening of the arteries in atherosclerosis. The aim of our study was to test this hypothesis. Endothelial function and arterial stiffness were assessed non-invasively by pulse wave analysis, and blood/urinary samples were taken in 39 patients with peripheral arterial disease as well as in 34 controls. The patients showed significantly reduced endothelial function index (EFI) and increased augmentation index (AIx), as well as higher estimated aortic pulse wave velocity (PWV) and elevated values of the intercellular adhesion molecule-1 (ICAM-1), high sensitivity C-reactive protein, myeloperoxidase and urinary 8-iso-prostaglandin F2a (F2-IsoPs). There was an inverse association between EFI and ICAM-1 (R = -0.44, p = 0.009) in the controls, but not in the patients. Augmentation index and estimated aortic PWV correlated with F2-IsoPs only in the patients (R = 0.5, p = 0.001; R = -0.43, p = 0.006, respectively). After controlling for potential confounders, these associations remained significant. The study demonstrates that impairment of endothelial vasomotor capacity is affected by degree of inflammation in the subclinical condition, whereas arterial stiffening is determined by level of oxidative modifications in atherosclerosis.

Whole-body basal nitric oxide production is impaired in postprandial endothelial dysfunction in healthy rats

In healthy humans, a high-saturated-fat/high-sucrose meal induces vascular endothelial dysfunction, a hallmark of atherogenesis. This transient dysfunction indicates a loss in nitric oxide (NO) production and/or bioactivity in the vasculature but it remains unknown if this is the local manifestation of a general impairment in NO pathway in the postprandial state. Here, we studied whole-body NO production and systemic NO bioactivity in postprandial endothelial dysfunction, as induced by a high-saturated-fat, high-sucrose meal. We first developed a physiological test of endothelial function on conscious rats, based on the transient fall in blood pressure after iv acetylcholine, and showed that this response was NO-dependent. As assessed with this method in healthy rats, endothelial function decreased during the postprandial state, being 60+/-7% lower than baseline at 6h after the meal challenge, associated with important elevations in plasma triglycerides and hydroperoxides. Aortic superoxide anion production, as assessed by oxidative fluorescent detection, was higher 6h after the meal challenge than after the nutrients vehicle (water). During the postprandial period, plasma cGMP, but not plasma ANP, markedly decreased, indicating a general decrease in NO bioavailability, which was numerically maximal 4h after the meal challenge. As determined 4h after ingestion by a tracer-based method using iv [(15)N(2)-(guanido)]-arginine, the whole-body NO production fell by 27+/-9% postprandially. This is the first study evidencing that a meal challenge that impairs the stimulated, NO-mediated, vascular response also reduces whole-body basal NO production and bioavailability. Postprandial pathophysiology may build on this general, fundamental alteration in NO production.

Vascular-Protective Effects of High-Density Lipoprotein Include the Downregulation of the Angiotensin II Type 1 Receptor

There is growing evidence that a cross-talk exists between the renin-angiotensin (Ang) system and lipoproteins. We investigated the role of high-density lipoprotein (HDL) on Ang II type 1 receptor (AT1R) regulation and subsequent Ang II–mediated signaling under diabetic conditions. To investigate the effect of HDL on AT1R expression in vivo, apolipoprotein A-I gene transfer was performed 5 days after streptozotocin injection. Six weeks after apolipoprotein A-I gene transfer, the 1.9-fold ( P =0.001) increase of HDL cholesterol was associated with a 4.7-fold ( P <0.05) reduction in diabetes mellitus–induced aortic AT1R expression. Concomitantly, NAD(P)H oxidase activity, Nox 4 , and p22 phox mRNA expression were reduced 2.6-fold, 2.0-fold, and 1.5-fold ( P <0.05), respectively, whereas endothelial NO synthase dimerization was increased 3.3-fold ( P <0.005). Apolipoprotein A-I transfer improved NO bioavailability as indicated by ameliorated acetylcholine-dependent vasodilation in the streptozotocin- Ad.hapoA-I group compared with streptozotocin-induced diabetes mellitus. In vitro, HDL reduced the hyperglycemia-induced upregulation of the AT1R in human aortic endothelial cells. This was associated with a 1.3-fold and 2.2-fold decreases in reactive oxygen species and NAD(P)H oxidase activity, respectively ( P <0.05). Finally, HDL reduced the responsiveness to Ang II, as indicated by decreased oxidative stress in the hyperglycemia+HDL+Ang II group compared with the hyperglycemia+Ang II group. In conclusion, vascular-protective effects of HDL include the downregulation of the AT1R.

C-reactive protein, metabolic syndrome and incidence of severe hip and knee osteoarthritis. A population-based cohort study

OBJECTIVE

To explore the relationships between C-reactive protein (CRP), metabolic syndrome (MetS) and incidence of severe knee or hip osteoarthritis (OA) in a prospective study.

METHODS

A population-based cohort (n=5171, mean age 57.5+/-5.9 years) was examined between 1991 and 1994. Data was collected on lifestyle habits, measures of overweight, blood pressure as well as high-density lipoprotein (HDL) cholesterol, triglycerides, glucose and CRP measured with high-sensitive methods. Incidence of severe OA, defined as arthroplasty due to knee or hip OA, was monitored over 12 years of follow-up, in relation to CRP levels and presence of the MetS according to the adult treatment panel III-national cholesterol education program (ATPIII-NCEP) definition.

RESULTS

A total of 120 participants had severe hip OA and 89 had knee OA during the follow-up. After adjustment for age, sex, smoking, physical activity and CRP, presence of MetS was associated with significantly increased risk of knee OA (relative risk [RR]: 2.1, 95% confidence interval [CI]: 1.3-3.3). However, this relationship was attenuated and non-significant after adjustment for body mass index (BMI) (RR: 1.1, 95% CI: 0.7-1.8). MetS was not significantly associated with incidence of hip OA. In women, CRP was associated with knee OA in the age-adjusted analysis. However, there was no significant relationship between CRP and incidence of knee or hip OA after risk factor adjustments.

CONCLUSION

The increased incidence of knee OA in participants with the MetS was largely explained by increased BMI. CRP was not associated with incidence of knee or hip OA when possible confounding factors were taken into account.

Relations between digital thermal monitoring of vascular function, the Framingham risk score, and coronary artery calcium score

BACKGROUND

Digital thermal monitoring (DTM) of vascular function was shown to correlate with the presence of known coronary artery disease (CAD).

OBJECTIVE

We evaluated whether DTM can identify at-risk, asymptomatic patients with significant coronary artery calcium (CAC) or increased Framingham risk score (FRS).

METHODS

Two hundred thirty-three consecutive asymptomatic subjects (58 +/- 11 years; 62% men) without known CAD underwent DTM, CAC, and FRS calculation. DTM measurements were obtained during and after a 5-minute suprasystolic arm-cuff occlusion. After cuff-deflation temperature rebound (TR) and area under the temperature curve (AUC) were measured and correlated with FRS and CAC.

RESULTS

TR was lower in patients with FRS > 20% and CAC >or= 100 as compared with FRS < 10% and CAC < 10, respectively (P < 0.05). After adjustment for age, sex, and traditional cardiac risk factors, the odds ratio of the lowest compared with the upper 2 tertiles of TR was 3.96 for FRS >or= 20% and 2.37 for CAC >or= 100 compared with low-risk cohorts. The area under the receiver operating characteristic (ROC) curve to predict CAC >or= 100 increased significantly from 0.66 for FRS to 0.79 for TR to 0.89 for TR + FRS.

CONCLUSIONS

Vascular dysfunction measured by DTM strongly correlates with FRS and CAC independent of age, sex, and traditional cardiac risk factors and was superior to FRS for the prediction of significant CAC.

Impaired aortic elastic properties in patients with systemic sarcoidosis

BACKGROUND

Systemic sarcoidosis (Sar) is a granulomatous disorder involving multiple organs. Widespread vascular involvement and microangiopathy are common in patients with Sar. In addition, subclinical cardiac involvement is increasingly recognized in patients with Sar. However, data on the effect of Sar on the elastic properties of the arteries and myocardial performance are limited. In this study we looked for differences in aortic distensibility (AoD) which is an index of aortic elasticity, and myocardial performance of the ventricles, between patients with Sar and healthy subjects. In addition, we examined potential associations between AoD and clinical, respiratory and echocardiographic findings in patients with Sar.

MATERIALS AND METHODS

A total of 83 consecutive patients (26 male/57 female, mean age 51.1 +/- 13.3 years) with Sar, without cardiac symptoms, were included. All patients underwent echocardiographic and respiratory evaluation including lung function tests. Additionally, 83 age- and sex-matched healthy subjects served as controls. AoD was determined non-invasively by ultrasonography.

RESULTS

AoD was lower in the Sar compared to the control group (2.29 +/- 0.26 vs. 2.45 +/- 0.20 .10(-) (6) cm2 x dyn(-1), P < 0.01), while left ventricular mass (LVM) was higher in the Sar group (221.3 +/- 50.2 vs. 195.6 +/- 31.3 g, P = 0.007). Furthermore, myocardial performance of both ventricles was impaired in the Sar group. Multivariate linear regression analysis in the total sample population demonstrated a significant and independent inverse relationship between AoD and the presence of Sar (P < 0.001). The same analysis in the Sar patients showed that AoD was associated significantly and independently with the stage of Sar, age, systolic blood pressure, LVM and myocardial performance of both ventricles. No significant relationship was found between AoD and disease duration, pulmonary artery pressure or lung function tests.

CONCLUSIONS

Presence and severity of Sar are associated with reduced aortic distensibility, irrespective of the disease duration, pulmonary artery pressure and lung function. In addition, patients with Sar have increased LVM and impaired myocardial performance.

Combined use of endothelial function assessed by brachial ultrasound and high-sensitive C-reactive protein in predicting cardiovascular events

BACKGROUND

Endothelial function plays a key role in determining the clinical manifestations of atherosclerotic lesions. Elevated high-sensitive C-reactive protein (hsCRP) relates to long-term prognosis of cardiovascular disease.

HYPOTHESIS

We test the hypothesis that combined use of endothelial function and hsCRP could increase predictive value of future cardiovascular events.

METHODS AND RESULTS

205 patients were followed up for a median period of 24 months. Endothelial function was assessed using brachial ultrasound to measure endothelium-dependent flow-mediated vasodilation (FMD). Cox regression analyses were conducted for the 205 subjects, with cardiovascular events being defined as myocardial infarction, hospitalization due to congestive heart failure, percutaneous coronary intervention, coronary artery bypass grafting, and ischemic stroke. Twenty nine (14%) developed cardiovascular events. Both FMD and hsCRP were significantly predictive of cardiovascular events (relative risk for patients with FMD<3% as compared to those with FMD>6%, 4.65, 95% confidence interval (CI): 1.30-16.66, p=0.018; relative risk for the highest as compared with the lowest tertile of hsCRP level, 3.59, 95% CI: 1.32-9.74, p=0.012, respectively). Further risk analysis was performed among four groups classified by FMD (FMD >or= 6% or<6%) and half percentile of hsCRP (hsCRP >or= 1 or<1 mg/dL). Relative risks for the FMD<6%/hsCRP >or= 1 mg/dL group compared to FMD >or= 6%/hsCRP<1 mg/dL group increased markedly to 12.598 (95% CI: 1.69 to 94.14, p=0.014) for cardiovascular events.

CONCLUSIONS

Patients with suspected coronary artery disease may benefit from risk stratification based on both endothelium-dependent FMD and hsCRP, since combined these two factors contribute significantly toward the incidence of cardiovascular events.

The vascular effects of metabolic impairment clusters in subjects of different ethnicities

BACKGROUND

Although metabolic syndrome affects vascular function, the impact of individual impairments and their clustering is unclear.

OBJECTIVE

To assess the vascular impact of metabolic impairments before they reach treatment thresholds in different ethnic groups.

METHODS

Metabolic variables, inflammatory markers, endothelium dependent vasodilatation (EDV) and carotid intima media thickness (CIMT) were measured in population samples of 82 Caucasians and 78 matched Afro-Caribbeans with no vascular disease. Insulin resistance was assessed using homeostasis model assessment (HOMA-IR). EDV was measured as the change in the height of the inflection point of the digital volume pulse following intravenous infusion of 5 mcg/min of albuterol (DeltaRIDeltaLB). Regression models were used to investigate the independent effects of metabolic impairment clusters and their interaction with ethnicity on EDV and CIMT.

RESULTS

HOMA-IR (2.4-3.8, p < 0.0001), IL-6 levels (1.1-2.8 pg/mL, p = 0.02) and CIMT (0.71-0.83 mm, p = 0.009) increased whereas in DeltaRIBASELINE (77.6-72.9 percentage points, p < 0.0001) and DeltaRIDeltaLB (15.5-7.1 percentage points, p < 0.0001) decreased with the number of metabolic impairments present. DeltaRIDeltaLB decreased by 1.6 (95% CI 0.2-3.7) percentage points and CIMT increased by 0.06 (95% CI 0.02-0.10) mm for each metabolic impairment present after adjusting for age, gender, ethnicity and HOMA-IR. There were significant interactions between Afro-Caribbean ethnicity and metabolic impairments for IL-6 (p = 0.037) and DeltaRIDeltaLB (p = 0.002).

CONCLUSIONS

Clustering of metabolic impairments is associated with inflammatory activation, impaired EDV and increased CIMT even before reaching treatment thresholds for individual impairments. This effect was more marked in Afro-Caribbean subjects.

Vascular endothelial and smooth muscle function relates to body mass index and glucose in obese and nonobese children

CONTEXT

Endothelial and smooth muscle dysfunction are critical precursors of atherosclerosis. These can be detected in children at risk of cardiovascular disease.

OBJECTIVE

The objective of this study is to evaluate endothelial and smooth muscle function and their determinants using flow-mediated dilatation (FMD) and glyceryl trinitrate-mediated dilatation (GTN) in obese, nonobese, and type 1 diabetes mellitus (T1DM) children.

DESIGN

This is a cross-sectional study.

SUBJECTS

The study subjects were 270 children [140 males, mean age 13.7 (2.8) yr] including 58 obese, 53 nonobese, and 159 T1DM children.

MEASUREMENTS

Vascular function (FMD and GTN), body mass index (BMI) z-score, blood pressure, glucose, glycosylated hemoglobin, lipids, folate, homocysteine, and high sensitive C-reactive protein were measured.

RESULTS

FMD and GTN were significantly lower in obese and T1DM compared with nonobese subjects (P < 0.001, P < 0.001). FMD and GTN were similarly reduced in obese and T1DM subjects (P = 0.22, P = 0.28). In all nondiabetic subjects (n = 111), both FMD and GTN were significantly and independently related to BMI z-score (r = -0.28, P = 0.003, beta = -0.36, P < 0.001) and weight z-score (beta = -0.31, P = 0.002; r = -0.52, P < 0.001). FMD related independently to total cholesterol (beta = -0.22, P = 0.02). GTN related independently to vessel diameter (beta = -0.49, P < 0.001). GTN related to glucose within the normal range (r = -0.34, P = 0.001).

CONCLUSIONS

Children with obesity and T1DM have a similar degree of vascular dysfunction. BMI and weight adjusted for age and sex relate to endothelial and smooth muscle function in nonobese and obese children. Glucose relates to smooth muscle function in nonobese nondiabetic children. This suggests a continuum effect of BMI and glucose within the normal range on vascular function in childhood.

Vascular compliance versus flow-mediated vasodilation: correlation with cardiovascular risk factors

Cardiovascular risk factors are associated with impaired endothelium dependent vasodilation and reduced vascular compliance. In this study, the correlation with cardiovascular risk factor score of two common techniques for assessing vascular function was compared. Risk factors and vascular function were evaluated in a study population of 122 people with peripheral arterial disease (PAD) or with risk factors for PAD (73 men and 49 women; mean age 69 years). A risk factor score was determined using Framingham criteria. Vascular compliance was assessed by pulse waveform analysis and simultaneous blood pressure measurement. Flow-mediated vasodilation of the brachial artery was measured using duplex ultrasonography. Participants with a high risk factor score had significantly reduced vascular compliance of large and small vessels. By contrast, the difference in flow-mediated vasodilation between those with a high or low risk factor score did not reach statistical significance. There was a significant negative correlation between vascular compliance and risk factor score. There was a similar trend between flow-mediated vasodilation and risk factor score, but this did not reach statistical significance. A measure of vascular compliance was more significantly correlated with cardiovascular risk factor score than was a measure of flow-mediated vasodilation in the study population. Neither technique provided values that were highly correlated with risk factor burden. Although flow-mediated vasodilation is a preferred research tool for assessing vascular function, technical limitations and biological variability may reduce its clinical application in assessing individual cardiovascular risk.

Effects of salbutamol and glyceryl trinitrate on large arterial stiffness are similar between patients with hypertension and adults with normal blood pressure

AIMS

Endothelial function is characteristically impaired in patients with hypertension. Endothelial function was assessed in men and women with hypertension using a recently described, non-invasive method.

METHODS

Twenty patients and 20 controls received salbutamol 400 microg and glyceryl trinitrate (GTN) 500 microg in a two-way randomized, single-blind study. Effects on augmentation index (AIx) were assessed using pulse wave analysis (PWA).

RESULTS

Responses (absolute AIx reduction and 95% confidence interval) to salbutamol were 8.4% (6.2, 10.6) and 8.3% (7.0, 9.6) in patients and controls, respectively, and those to GTN were 13.6% (10.8, 16.4) and 15.5% (13.0, 17.0), respectively.

CONCLUSIONS

Systemic arterial responses to endothelium-dependent and -independent vasodilators are preserved in patients with mild, uncomplicated hypertension, indicating normal large arterial endothelial function.

Effect of fat distribution on endothelial-dependent and endothelial-independent vasodilatation in healthy humans

AIM

The present study aims to explore the relationship between inflammatory cytokines, plasma lipids, insulin, blood pressure (BP), total adiposity/markers of fat distribution and endothelial function in healthy people across a wide range of body fatness.

METHODS

Seventy-three healthy people (44 women; age range: 24-64 years) with body mass index (BMI) range of 18.6-73.1 kg/m2 were recruited. All participants underwent assessment of conduit artery endothelial-dependent vasodilatation by using flow-mediated vasodilatation (FMD) of the brachial artery and endothelial-independent vasodilatation to sublingual GTN. They had blood taken for measurement of plasma markers of glucose homeostasis (fasting insulin and glucose), systemic inflammation (interleukin-6 (IL-6), C-reactive protein (CRP) and tumour necrosis factor-alpha receptor 2 (TNF-alpha R2)) and lipids (low-density lipoprotein (LDL), high-density lipoprotein (HDL) and triglycerides). Morphometric assessment (waist circumference, BMI and waist-to-hip ratio (WHR)) and systolic and diastolic arterial pressure were also measured.

RESULTS

Markers of total body fat/fat distribution (waist circumference, BMI and WHR), inflammation (IL-6, CRP and TNF-alpha R2), metabolism (fasting insulin, HDL, LDL and triglycerides) and BP (systolic and diastolic) correlated with FMD. Among these measurements, WHR was the only independent predictor of FMD (r2 = 0.30; p = 0.0001).

CONCLUSIONS

WHR is an important marker of endothelial dysfunction in healthy people across a wide range of body fatness.

Coronary heart disease in women: why the disproportionate risk?

Women with diabetes experience much greater relative risks of coronary heart disease (CHD) compared with the nondiabetic population than do men with diabetes. In type 2 diabetes, much of the greater elevation in risk in women is explained by a more adverse pattern of known CHD risk factors. In type 1 diabetes the picture is less clear, but current evidence suggests that a cardioprotective lipid profile is found in type 1 diabetic men, thus reducing the effect of diabetes on CHD, but that in women this is not the case. Also, in type 1 diabetic women there is some evidence of altered body fat distribution and a greater elevation in blood pressure. Whether these reflect a greater degree of insulin resistance in type 1 women, and what the origin of this might be, remains controversial. The practical consequence is that clinicians need to be aware that the usual cardioprotective effect of sex does not apply in diabetic women and that risk factor intervention is needed at an early age.

Short duration of reactive hyperemia in the forearm of subjects with multiple cardiovascular risk factors

BACKGROUND

Peripheral vascular endothelial dysfunction is an independent predictor of cardiovascular events, and can be assessed noninvasively by measuring reactive hyperemia, either by vascular ultrasound measurement of flow-mediated vasodilatation or, less commonly, by measurement of blood flow using plethysmography. In the present study reactive hyperemia was measured using plethysmography in healthy subjects with multiple cardiovascular risk factors.

METHODS AND RESULTS

Reactive hyperemia was measured following 5-min occlusion of the upper arm in 449 healthy subjects (302 men, 147 women, age range 20-70 years) with (n=352) and without (n=97) risk factors such as smoking, hypertension, diabetes mellitus, hypercholesterolemia, obesity, family history of cardiovascular disease, and menopause. Maximum blood flow and minimum vascular resistance in reactive hyperemia did not differ between subjects with and without risk factors regardless of gender. Duration of reactive hyperemia, however, was significantly shorter in subjects with risk factors. Age-adjusted mean value of duration of reactive hyperemia was significantly smaller in men with a smoking habit, diabetes mellitus, hypercholesterolemia or obesity, and in women with smoking habit, hypertension, diabetes mellitus or obesity. The number of risk factors significantly correlated with the duration of reactive hyperemia in both men (r=-0.56, p<0.001) and women (r=-0.62, p<0.001), suggesting that endothelial dysfunction increases with the number of risk conditions clustering in a single individual.

CONCLUSIONS

Duration of reactive hyperemia reflects cardiovascular risk factors and decreases with the number of risk conditions. These findings suggest that the duration of reactive hyperemia measured with plethysmography is potentially useful for assessing endothelial dysfunction.

Modulation of endothelial and smooth muscle function by bed rest and hypoenergetic, low-fat nutrition

Prolonged microgravity alters the regulation of the peripheral vasculature. The influence of reduced food intake, as often observed in astronauts, on vascular function is unclear. In a randomized, four-phase, crossover study, the effect of simulated microgravity (13 days of bed rest), energetic restriction (-25%, fat reduced), and their combination on endothelium-dependent and -independent vasodilation was compared with ambulatory control conditions. Using venous occlusion plethysmography, cumulative intra-arterial dose-response curves to endothelium-dependent (acetylcholine) and -independent (sodium nitroprusside) vasodilators were constructed in 10 healthy male volunteers before and on day 13 of each of the four intervention periods. Bed rest combined with normoenergetic nutrition impaired the dose-response to acetylcholine (ANOVA, P = 0.004) but not to sodium nitroprusside, whereas hypoenergetic diet under ambulatory conditions improved responses to acetylcholine (P = 0.044) and sodium nitroprusside (P < 0.001). When bed rest was combined with hypoenergetic diet, acetylcholine responses did not change. Similarly, under control conditions, no change was observed. Individual changes in the total cholesterol-to-HDL ratio were correlated with changes in endothelial and vascular smooth muscle relaxation. In conclusion, short-term bed rest impairs endothelium-dependent arterial relaxation in humans. A hypoenergetic, low-fat diet modulates serum lipids, improves endothelium-dependent and -independent relaxation, and may antagonize the unfavorable effects of simulated microgravity on endothelial function.

A Comparison of Three Different Methods to Evaluate Endothelium-Dependent Vasodilation in the Elderly

Background— Three different techniques to evaluate endothelium-dependent vasodilation in the peripheral circulation have been described but not simultaneously tested in a large-scale population-based setting. This study aimed to evaluate the feasibility and usefulness of these techniques in the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study.

Methods and Results— In the population-based PIVUS study (1016 subjects aged 70 years), the invasive forearm technique with acetylcholine given in the brachial artery (EDV), the brachial artery ultrasound technique with measurement of flow-mediated dilatation (FMD), and the pulse wave analysis method with β-2-agonist (terbutaline) provocation were successfully used in 87%, 97%, and 86% of the sample, respectively. The results of EDV and pulse wave analysis were interrelated ( r =0.12, P =0.0013), but no relationships were found with FMD measurements. All 3 techniques were correlated to the Framingham risk score ( r =0.10 to 0.12, P =0.0007 to 0.001). In multiple regression analysis, however, only EDV and FMD were independently associated with the Framingham score.

Conclusions— All 3 evaluated techniques were feasible to perform in a general elderly population. Both the invasive forearm technique and FMD were independently associated with increased coronary risk, suggesting that information on conduit artery and resistance artery endothelial function carry different, but important, information in the elderly. If the invasive technique cannot be used, the pulse wave based technique is an alternative.

Impaired endothelial function in patients with ankylosing spondylitis

OBJECTIVE

In recent years, accelerated atherosclerosis and increased risk of cardiovascular events have been described in patients with rheumatic disease, particularly for rheumatoid arthritis and systemic lupus erythematosus. However, the link between inflammation, atherosclerosis and ankylosing spondylitis is controversial. We evaluated the degree of atherosclerosis and endothelial function of ankylosing spondylitis patients ultrasonographically.

METHODS

Fifty-four patients with ankylosing spondylitis (37 +/- 11 yr, 29 males, 25 females) and 31 healthy controls (35 +/- 9 yr, 16 males, 15 females) were consecutively enrolled in the study. Serum lipids, creatinine, glucose, and acute-phase proteins were assessed. The Bath Ankylosing Spondylitis Metrology Index (BASMI), Bath Ankylosing Spondylitis Functional Index (BASFI) and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) were also evaluated. Flow-mediated dilatation and endothelium-independent dilatation of the brachial artery and intima-media thickness of the common carotid artery were measured sonographically.

RESULTS

Left, right and averaged intima-media thickness of the common carotid artery did not show a statistically significant difference between the ankylosing spondylitis and control groups. However, flow-mediated dilatation was significantly lower in the ankylosing spondylitis patients (14.1 +/- 6.7 vs 17.6 +/- 8%; P = 0.03). Likewise, nitroglycerin-induced dilatation was lower in the patient group, but the difference was not significant (16.4 +/- 6.8 vs 19.8 +/- 10%; P = 0.07). No correlation was detected between flow-mediated dilatation and age, sex, serum lipids, CRP, ESR, smoking habits and disease activity scores. Intima-media thickness of the common carotid artery was positively correlated with age and BASMI score (r = 0.55, P = 0.00; r = 0.22, P = 0.04, respectively).

CONCLUSION

This study demonstrates impairment of endothelial function in ankylosing spondylitis.

The role of total and high-molecular-weight complex of adiponectin in vascular function in offspring whose parents both had type 2 diabetes

AIMS/HYPOTHESIS

Adiponectin is an adipokine with insulin-sensitising and anti-atherogenic properties. We studied the role played by total adiponectin and by the bioactive high-molecular-weight (HMW) oligomeric complexes of adiponectin in vascular function in offspring whose parents both had type 2 diabetes, a population at high risk of diabetes and atherosclerosis.

METHODS

Total and %HMW adiponectin, the cytokines C-reactive protein, interleukin-6 and plasminogen activator inhibitor-1 (PAI-1), as well as lipid profiles were assayed in 19 offspring, each with two type 2 diabetic parents. Subjects underwent OGTTs and IVGTTs. Endothelium-dependent vasodilation (EDV) was assessed by brachial artery ultrasonography.

RESULTS

There was a significant relationship between %HMW and total adiponectin levels (r=0.72, p=0.001). Despite an expected strong positive correlation between HDL-cholesterol and adiponectin levels (r=0.52, p=0.04), as well as HDL-cholesterol and EDV (r=0.56, p<0.02), there was no significant relationship between either total adiponectin or % HMW adiponectin and EDV. Adiponectin was inversely associated with PAI-1 (r=0.50, p=0.05), but did not correlate with the inflammatory markers C-reactive protein or interleukin-6.

CONCLUSIONS/INTERPRETATION

In offspring of diabetic parents, a population at high risk of diabetes and atherosclerotic disease, there is no relationship between total or %HMW adiponectin and endothelium-dependent vasodilation. However, low adiponectin was associated with impaired fibrinolysis as manifested by increased levels of plasminogen activator inhibitor-1.

A novel endothelial function test using Doppler flow: the snuff-box technique

Precise measurement of Doppler estimated blood flow volume using the standard technique of flow-mediated vasodilation is not possible because the anatomic course of the brachial or radial artery goes against the principle of Doppler measurements that the insonation angle should be less than 30 degrees . The radial artery in the anatomic snuff-box area is useful for the measurement of Doppler signals as the insonation angle is less than 30 degrees and because the size of the artery allows observation of laminar flow. We introduce the snuff-box technique as a novel endothelial function test that enables measurement of both blood flow and diameter of the radial artery. Changes in diameter and blood flow volume during reactive hyperemia were examined in 15 healthy volunteers. Changes in blood flow determined using the snuff-box technique were compared with changes in forearm blood flow determined by plethysmography. The diameter of the radial artery increased from 2.3 +/- 0.2 mm at baseline to 2.8 +/- 0.4 mm at 60 s after deflation (P = 0.0017), and blood flow increased from 52.3 +/- 21.4 ml/min at baseline to 108.6 +/- 33.1 ml/min at 15 s after deflation (P = 0.0014). Percentile blood flow determined by the snuff-box technique correlated significantly with that determined by plethysmography (r = 0.824, P = 0.0002). Both blood flow volume and artery diameter can be measured with high reliability using the snuff-box technique, as has been shown in subjects with reactive hyperemia.