Endothelial dysfunction, carotid artery plaque burden, and conventional exercise-induced myocardial ischemia as predictors of coronary artery disease prognosis

Human umbilical cord mesenchymal stem cells regulate CD54 and CD105 in vascular endothelial cells and suppress inflammation in Kawasaki disease

OBJECTIVE

The objective was to evaluate the expression levels of CD31⁺CD54⁺ and CD31⁺CD105⁺ endothelial microparticles (EMPs) before and after intravenous immunoglobulin (IVIG) treatment of Kawasaki disease (KD). To explore the role of human umbilical cord mesenchymal stem cells (hucMSCs) in inhibiting endothelial inflammation in KD, the effects of hucMSCs on the expression of CD54 and CD105 in endothelial cells in KD were analyzed in vivo and in vitro.

METHODS

The concentrations of IL-1β and VEGF in the peripheral blood of KD or healthy children were detected, and the distributions of CD31⁺CD54⁺ and CD31⁺CD105⁺ EMPs in platelet-poor plasma (PPP) were analyzed by flow cytometry. Human umbilical vein endothelial cells (HUVECs) were first cocultured with the patients' peripheral blood mononuclear cells (PBMCs). Next, HUVECs were cocultured with hucMSCs after stimulation with inactivated serum from patients. Cell proliferation and migration activities were assessed, and the expression of CD54, CD105 and IL-1β was analyzed. In an in vivo study, hucMSCs were transplanted into KD mice. The locations and expression levels of CD54, CD105 and IL-1β in the heart tissues of mice were analyzed.

RESULTS

The levels of IL-1β and CD31⁺CD54⁺ EMPs were significantly higher before IVIG treatment and 2 weeks after treatment in KD patients (P < 0.01). However, the levels of VEGF and CD31⁺CD105⁺ EMPs increased significantly in KD only after IVIG treatment (P < 0.01). KD-inactivated serum stimulation combined with cocultivation of PBMCs can activate inflammation in HUVECs, leading to reduced cell proliferation and migration activities. Cocultivation also increased the expression of CD54 and decreased the expression of CD105 (P < 0.001). Cocultivation with hucMSCs can reverse these changes. Additionally, hucMSC transplantation downregulated the expression of IL-1β and CD54 and significantly upregulated the expression of CD105 in KD mice.

CONCLUSION

The expression levels of CD31⁺CD54⁺ and CD31⁺CD105⁺ EMPs showed inconsistent changes at different KD statuses, providing potential markers for clinical application. HucMSCs suppress inflammation and regulate the expression levels of CD54 and CD105 in vascular endothelial cells in KD, possibly providing a new basis for stem cell therapy for KD.

Effects of Lifestyle Modification on Patients With Resistant Hypertension: Results of the TRIUMPH Randomized Clinical Trial

BACKGROUND

Although lifestyle modifications generally are effective in lowering blood pressure (BP) among patients with unmedicated hypertension and in those treated with 1 or 2 antihypertensive agents, the value of exercise and diet for lowering BP in patients with resistant hypertension is unknown.

METHODS

One hundred forty patients with resistant hypertension (mean age, 63 years; 48% female; 59% Black; 31% with diabetes; 21% with chronic kidney disease) were randomly assigned to a 4-month program of lifestyle modification (C-LIFE [Center-Based Lifestyle Intervention]) including dietary counseling, behavioral weight management, and exercise, or a single counseling session providing SEPA (Standardized Education and Physician Advice). The primary end point was clinic systolic BP; secondary end points included 24-hour ambulatory BP and select cardiovascular disease biomarkers including baroreflex sensitivity to quantify the influence of the baroreflex on heart rate, high-frequency heart rate variability to assess vagally mediated modulation of heart rate, flow-mediated dilation to evaluate endothelial function, pulse wave velocity to assess arterial stiffness, and left ventricular mass to characterize left ventricular structure.

RESULTS

Between-group comparisons revealed that the reduction in clinic systolic BP was greater in C-LIFE (-12.5 [95% CI, -14.9 to -10.2] mm Hg) compared with SEPA(-7.1 [-95% CI, 10.4 to -3.7] mm Hg) (P=0.005); 24-hour ambulatory systolic BP also was reduced in C-LIFE (-7.0 [95% CI, -8.5 to -4.0] mm Hg), with no change in SEPA (-0.3 [95% CI, -4.0 to 3.4] mm Hg) (P=0.001). Compared with SEPA, C-LIFE resulted in greater improvements in resting baroreflex sensitivity (2.3 ms/mm Hg [95% CI, 1.3 to 3.3] versus -1.1 ms/mm Hg [95% CI, -2.5 to 0.3]; P<0.001), high-frequency heart rate variability (0.4 ln ms² [95% CI, 0.2 to 0.6] versus -0.2 ln ms² [95% CI, -0.5 to 0.1]; P<0.001), and flow-mediated dilation (0.3% [95% CI, -0.3 to 1.0] versus -1.4% [95% CI, -2.5 to -0.3]; P=0.022). There were no between-group differences in pulse wave velocity (P=0.958) or left ventricular mass (P=0.596).

CONCLUSIONS

Diet and exercise can lower BP in patients with resistant hypertension. A 4-month structured program of diet and exercise as adjunctive therapy delivered in a cardiac rehabilitation setting results in significant reductions in clinic and ambulatory BP and improvement in selected cardiovascular disease biomarkers. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02342808.

The value of real-time myocardial contrast echocardiography for detecting coronary microcirculation function in coronary artery disease patients

Objective:

The aim of this study was to evaluate the value of real-time myocardial contrast echocardiography (RT-MCE) for detecting coronary microcirculation (CM) function in coronary artery disease (CAD) patients.

Methods:

Sixty-five consecutive patients were divided into CAD (n=52) and no-CAD (n=13) groups using coronary angiography (CAG). All patients underwent RT-MCE at rest and CAG within 1 week after RT-MCE. The ventricular segments in CAD patients were divided semi-quantitatively into ischemic and non-ischemic myocardial groups based on RT-MCE images. Myocardial blood volume (A), myocardial blood flow velocity (β), and mean myocardial blood flow (A×β) were obtained. The Gensini scores were calculated for CAD patients. The receiver operating characteristic (ROC) curve areas of A, β, and A×β were calculated to assess CM function in CAD patients.

Results:

A total of 798 and 204 segments were investigated in the CAD and non-CAD groups, respectively. In CAD patients, 332 ischemic and 466 non-ischemic segments were identified. The values of A, β, and A×β were significantly different among non-CAD, CAD, ischemic, and non-ischemic groups. ROC curve areas of A, β, and A×β were 0.85, 0.79, and 0.83, respectively, and significant differences were observed in these values among three Gensini score groups of the CAD patients.

Conclusion:

Varying degrees of CM function deterioration was observed in CAD patients both in ischemic and non-ischemic areas, with the deterioration being more sever in the former.

MicroRNA-145-5p and microRNA-320a encapsulated in endothelial microparticles contribute to the progression of vasculitis in acute Kawasaki Disease

Kawasaki Disease (KD) is an acute inflammatory disease that takes the form of systemic vasculitis. Endothelial microparticles (EMPs) have been recognized as an important transcellular delivery system. We hypothesized whether EMPs are involved in vasculitis in acute KD. Fifty patients with acute KD were enrolled, divided into two subgroups: those with coronary artery lesions (CAL) (n = 5) and those without CAL (NCAL) (n = 45). EMPs were measured using flow cytometry, and microRNA (miR) expression profiling was performed by microRNA array. The percentage of EMPs in acute KD was significantly higher than in controls (P < 0.0001). EMPs in patients with CAL rapidly increased after the initial treatment, and was significantly higher than those in NCAL (P < 0.001). In patients with CAL, we identified 2 specific miRs encapsulated in EMPs, hsa-miR-145-5p and hsa-miR-320a, which are predicted to affect monocyte function using in silico analysis, and were demonstrated to upregulate inflammatory cytokine mRNAs in THP-1 monocytes. In situ hybridization confirmed that hsa-miR-145-5p was preferentially expressed in CAL. EMPs may serve as a sensitive marker for the severity of vasculitis in acute KD. Moreover, these 2 specific miRs encapsulated in EMPs might be involved in inflammatory cytokine regulation and the pathogenesis of vasculitis in acute KD.

Prognostic Value of Flow-Mediated Vasodilation in Brachial Artery and Fingertip Artery for Cardiovascular Events: A Systematic Review and Meta-Analysis

BACKGROUND

Endothelial dysfunction plays a pivotal role in cardiovascular disease progression, and is associated with adverse events. The purpose of this systematic review and meta-analysis was to investigate the prognostic magnitude of noninvasive peripheral endothelial function tests, brachial artery flow-mediated dilation (FMD), and reactive hyperemia--peripheral arterial tonometry (RH-PAT) for future cardiovascular events.

METHODS AND RESULTS

Databases of MEDLINE, EMBASE, and the Cochrane Library were systematically searched. Clinical studies reporting the predictive value of FMD or RH-PAT for cardiovascular events were identified. Two authors selected studies and extracted data independently. Pooled effects were calculated as risk ratio (RR) for continuous value of FMD and natural logarithm of RH-PAT index (Ln_RHI) using random-effects models. Thirty-five FMD studies of 17 280 participants and 6 RH-PAT studies of 1602 participants were included in the meta-analysis. Both endothelial function tests significantly predicted cardiovascular events (adjusted relative risk [95% CI]: 1% increase in FMD 0.88 [0.84-0.91], P<0.001, 0.1 increase in Ln_RHI 0.79 [0.71-0.87], P<0.001). There was significant heterogeneity in the magnitude of the association across studies. The magnitude of the prognostic value in cardiovascular disease subjects was comparable between these 2 methods; a 1 SD worsening in endothelial function was associated with doubled cardiovascular risk.

CONCLUSIONS

Noninvasive peripheral endothelial function tests, FMD and RH-PAT, significantly predicted cardiovascular events, with similar prognostic magnitude. Further research is required to determine whether the prognostic values of these 2 methods are independent of each other and whether an endothelial function-guided strategy can provide benefit in improving cardiovascular outcomes.

A meta-analysis of published studies of endothelial dysfunction does not support its routine clinical use

BACKGROUND

Endothelial dysfunction is a marker of future cardiovascular disease (CVD) risk, yet epidemiological studies have yielded inconsistent results. We therefore studied the association between endothelial dysfunction and CVD under diverse circumstances.

METHODS AND RESULTS

Literature-based meta-analysis of prospective observational studies with ≥ 12 months of follow-up published in Medline and having information on endothelial function and CVD outcomes. Tabular data on participant characteristics, endothelial function assessments and incident CVD outcomes were abstracted from individual studies. Random-effects meta-analysis was used to quantify pooled associations, and I(2) statistic to evaluate between-study heterogeneity. Potential sources of heterogeneity were explored by subgroup analyses and meta-regression. Thirty five studies involving 17,206 participants met the inclusion criteria. During more than 80,000 person-years of observation, up to 2755 CVD events were accrued, yielding a pooled relative risk (RR) of 1.25 (95% confidence interval 1.15-1.35) for CVD comparing top (i.e. more severe) vs. bottom (less severe) third of endothelial dysfunction. There was significant between-study heterogeneity and evidence of publication bias. RRs varied importantly according to the method used to ascertain endothelial function, and were higher among older individuals and among participants with risk factors for CVD or established CVD at baseline.

CONCLUSIONS

Although endothelial dysfunction is an important determinant of cardiovascular outcomes in people with pre-existing CVD, current evidence base does not support its use as a potentially useful measurement for risk stratification in people at lower risk of CVD.

Vascular Effects of Dietary Advanced Glycation End Products

Evidence has accumulated lately demonstrating that advanced glycation end products (AGEs) play an important role in the development of diabetic and cardiovascular complications as well as the development of other chronic diseases. AGEs originating from diet have a significant contribution to the AGEs body pool and therefore dietary interventions aiming at reducing AGEs load are believed to exert health promoting effects. This review summarizes the evidence from clinical studies regarding effects of dietary AGEs on the vascular system, highlighting also the different aspects of vascular tests. It also advocates an extension of dietary recommendations towards the promotion of cooking methods that reduce dietary AGEs in consumed foods.

Mineral Metabolism Markers Are Associated with Myocardial Infarction and Hemorrhagic Stroke but Not Ischemic Stroke in Hemodialysis Patients: A Longitudinal Study

BACKGROUND/AIMS

The associations between phosphate, calcium, and intact parathyroid hormone (PTH) levels and composite cardiovascular end points have been studied. This study examined the associations of these markers with myocardial infarction (MI) and stroke separately.

METHODS

This is a longitudinal study on 65,849 hemodialysis patients from the Japan Renal Data Registry. Patients with prior events at baseline were excluded. Predictors were phosphate, albumin-corrected calcium, intact PTH, and calcium times phosphate product levels. Outcome was the first episode of MI or stroke during a 1-year observation period. Data were analyzed using multiple logistic regression analyses, adjusted for potential confounders.

RESULTS

There were 1,048, 651, and 2,089 events of incident MI, hemorrhagic, and ischemic stroke, respectively. Incident MI was associated with phosphate levels ≥6.5 mg/dL (odds ratio 1.49; confidence interval 1.23-1.80) compared with phosphate levels of 4.7-5.4 mg/dL and intact PTH levels>500 pg/mL (1.35; 1.03-1.79) compared with intact PTH levels of 151-300 pg/mL. Higher albumin-corrected calcium level was positively associated with MI (p = 0.04 by trend analysis). Hemorrhagic stroke was associated only with intact PTH levels>500 pg/mL (1.54; 1.10-2.17). Incident ischemic stroke had no association with phosphate, calcium, or intact PTH levels. The association of calcium times phosphate product with outcomes was essentially the same pattern as that of phosphate and outcomes.

CONCLUSIONS

MI was associated with phosphate, calcium, and intact PTH levels, whereas hemorrhagic stroke was associated only with intact PTH. Ischemic stroke was not associated with any of them. The potential distinct beneficial effect on MI and stroke by managing bone and mineral disease should be investigated in future studies.

Brachial artery endothelial responses during early recovery from an exercise bout in patients with coronary artery disease

This study examined the acute endothelial responses to an exercise bout in coronary artery disease (CAD) patients. Nineteen males with CAD (63 ± 8 years) were assessed at rest and 15 minutes following a submaximal exercise bout (recovery). Brachial artery endothelial-dependent function was assessed using flow-mediated dilation (FMD). Brachial artery diameters and velocities were measured using Duplex ultrasound at baseline, and for 3 minutes following a 5-minute ischemic period. Endothelial-independent function was assessed using a 0.4 mg dose of nitroglycerin (NTG). FMD responses were unchanged from rest to recovery; however, there were 2 types of responses: negative and positive FMD responders. Post-hoc analysis revealed that positive responders had lower resting FMD compared to negative responders (3.2 ± 1.7 versus 6.0 ± 2.5%, P < 0.05). NTG-mediated dilation was reduced in recovery (22.0 ± 5.6 versus 14.4 ± 5.7%, P < 0.001 for rest versus recovery). In conclusion, acute endothelial-dependent responses to submaximal exercise are affected by the degree of resting endothelial dysfunction. The observation of attenuated NTG-mediated dilation during recovery is novel and warrants the investigation of possible mechanisms and clinical significance. Furthermore, it highlights the necessity of both endothelial-dependent and endothelial-independent assessments when evaluating endothelial function changes with an intervention.

Non-invasive endothelial function testing and the risk of adverse outcomes: a systematic review and meta-analysis

OBJECTIVES

We performed a systematic review and meta-analysis to understand the role of flow-mediated dilatation (FMD) of the brachial artery (BA) and peripheral arterial tonometry (PAT) in predicting adverse events, including cardiovascular (CV) events and all-cause mortality.

BACKGROUND

FMD of the BA and PAT are non-invasive measures of endothelial function. Impairment of endothelial function is associated with increased CV events. While FMD is the more widely used and studied technique, PAT offers several advantages. The purpose of this systematic review and meta-analysis is to determine whether brachial FMD and PAT are independent risk factors for future CV events and mortality.

METHODS

Multiple electronic databases were searched for articles relating FMD or PAT to CV events. Data were extracted on study characteristics, study quality, and study outcomes. Relative risks (RRs) from individual studies were combined and a pooled multivariate RR was calculated.

RESULTS

Thirty-six studies for FMD were included in the systematic review, of which 32 studies consisting of 15, 191 individuals were meta-analysed. The pooled RR of CV events and all-cause mortality per 1% increase in brachial FMD, adjusting for potential confounders, was 0.90 (0.88-0.92). In contrast, only three studies evaluated the prognostic value of PAT for CV events, and the pooled RR per 0.1 increase in reactive hyperaemia index was 0.85 (0.78-0.93).

CONCLUSION

Brachial FMD and PAT are independent predictors of CV events and all-cause mortality. Further research to evaluate the prognostic utility of PAT is necessary to compare it with FMD as a non-invasive endothelial function test in clinical practice.

Protective effects of dark chocolate on endothelial function and diabetes

PURPOSE OF REVIEW

Relationship between cocoa consumption and cardiovascular disease, particularly focusing on clinical implications resulting from the beneficial effects of cocoa consumption on endothelial function and insulin resistance. This could be of clinical relevance and may suggest the mechanistic explanation for the reduced risk of cardiovascular events reported in the different studies after cocoa intake.

RECENT FINDINGS

Increasing evidence supports a protective effect of cocoa consumption against cardiovascular disease. Cocoa and flavonoids from cocoa have been described to improve endothelial function and insulin resistance. A proposed mechanism could be considered in the improvement of the endothelium-derived vasodilator nitric oxide by enhancing nitric oxide synthesis or by decreasing nitric oxide breakdown.

SUMMARY

The endothelium plays a pivotal role in the arterial homeostasis, and insulin resistance is the most important pathophysiological feature in various prediabetic and diabetic states. Reduced nitric oxide bioavailability with endothelial dysfunction is considered the earliest step in the pathogenesis of atherosclerosis. Further, insulin resistance could account, at least in part, for the endothelial dysfunction. Endothelial dysfunction has been considered an important and independent predictor of future development of cardiovascular risk and events. Cocoa and flavonoids from cocoa might positively modulate these mechanisms with a putative role in cardiovascular protection.

A randomized, double-blind, crossover, placebo-controlled trial of 6 weeks benfotiamine treatment on postprandial vascular function and variables of autonomic nerve function in Type 2 diabetes

AIMS

In a pilot study we suggested that benfotiamine, a thiamine prodrug, prevents postprandial endothelial dysfunction in people with Type 2 diabetes mellitus. The aim of this study was to test these effects in a larger population.

METHODS

In a double-blind, placebo-controlled, randomized, crossover study, 31 people with Type 2 diabetes received 900 mg/day benfotiamine or a placebo for 6 weeks (with a washout period of 6 weeks between). At the end of each treatment period, macrovascular and microvascular function were assessed, together with variables of autonomic nervous function in a fasting state, as well as 2, 4 and 6 h following a heated, mixed test meal.

RESULTS

Participants had an impaired baseline flow-mediated dilatation (2.63 ± 2.49%). Compared with the fasting state, neither variable changed postprandially following the placebo treatment. The 6 weeks' treatment with high doses of benfotiamine did not alter this pattern, either in the fasting state or postprandially. Among a subgroup of patients with the highest flow-mediated dilatation, following placebo treatment there was a significant postprandial flow-mediated dilatation decrease, while this effect was attenuated by benfotiamine pretreatment.

CONCLUSIONS

In people with Type 2 diabetes and markedly impaired fasting flow-mediated dilatation, a mixed test meal does not further deteriorate flow-mediated dilatation or variables of microvascular or autonomic nervous function. Because no significant deterioration of postprandial flow-mediated dilatation, microvascular or autonomic nervous function tests occurred after placebo treatment, a prevention of the postprandial deterioration of these variables with benfotiamine was not feasible.

Forearm muscle oxygenation responses during and following arterial occlusion in patients with mitochondrial myopathy

The aim was to study whether mitochondrial myopathy induces different oxygenation (deoxy[Hb+Mb] and oxy[Hb+Mb]) responses during and following arterial occlusion. In 10 mitochondrial myopathy patients (MMpatients) (age: 29±7 years; body mass: 59.9±15.7kg; heigth: 166.2±11.4cm) and age- and gender-matched healthy subjects (age: 28±9 years; body mass: 72.7±16.9kg; height: 174.4±8.7cm) arterial occlusion was performed by inflating a cuff to 240mmHg. Deoxy[Hb+Mb] and oxy[Hb+Mb] were registered during (AOoxy and AOdeoxy) and following (POdeoxy and POoxy) arterial occlusion. Amplitude of AOdeoxy did not differ (p=0.47) between MMpatients (44.9±28.0μM) and healthy subjects (38.6±22.8μM), The time constant of the exponential model was greater in MMpatients (263.4±49.1s vs. 200.3±73.7s, p=0.03). Following cuff release, in both populations a transient increase in total[Hb+Mb] was observed induced by different kinetics of POoxy and POdeoxy. The increase in POoxy (TD=6.6±2.2s and 11.9±3.5s; τ=3.8±1.4s and 6.4±2.9s for MMpatients and healthy subjects, respectively) was faster (p<0.001 for TD and τ) compared to the decrease in POdeoxy (TD=13.2±3.6s and 26.5±4.6s; τ=-6.2±2.2s and -9.6±2.4s for MMpatients and healthy subjects, respectively). POoxy and POdeoxy showed faster kinetics (p<0.001 and p<0.01 for TD and τ, respectively) in MMpatients compared to healthy subjects. MMpatients display altered oxygenation responses during and following arterial occlusion reflecting pathology related changes in the relationship between muscle blood flow and oxygen uptake.

Stretching exercises enhance vascular endothelial function and improve peripheral circulation in patients with acute myocardial infarction

The purpose of this study was to clarify the acute effects of a single session of stretching exercises on vascular endothelial function and peripheral circulation in patients with acute myocardial infarction. This study evaluated 32 patients (mean age, 66 ± 9 years) who received phase I cardiac rehabilitation after acute myocardial infarction. Five types of stretching exercises were performed on the floor: wrist dorsiflexion, close-legged trunk flexion, open-legged trunk flexion, open-legged lateral trunk bending, and cross-legged trunk flexion. Each exercise entailed a 30-second stretching followed by a 30-second relaxation, and was repeated twice. Low- and high-frequency components (LF and HF) of heart rate variability (LF, 0.04-0.15 Hz; HF, 0.15-0.40 Hz) were analyzed, and HF and LF/HF were used as indices of parasympathetic and sympathetic nervous activities, respectively. Reactive hyperemia peripheral arterial tonometry (RH-PAT) index was measured and used as a parameter for vascular endothelial function. Transcutaneous oxygen pressure (tcPO2) on the right foot and chest was also measured, and the Foot-tcPO2/Chest-tcPO2 ratio was used as a parameter for peripheral circulation. The HF, RH-PAT index, and Foot-tcPO2/Chest-tcPO2 ratio were significantly higher after the exercises than before (P < 0.05, P < 0.01, and P < 0.05, respectively). There was no significant difference in the LF/HF ratio measured before and after stretching exercises. These findings demonstrate that stretching exercises improve vascular endothelial function and peripheral circulation in patients with acute myocardial infarction.

Relationship of depression, stress and endothelial function in stable angina patients

Endothelial dysfunction has been considered as one of potential mechanisms by which depression and stress might contribute to the development of coronary artery disease (CAD). Recent studies suggest that circulating endothelial progenitor cells (EPCs) and brachial artery flow-mediated dilation (FMD) are related to endothelial function and progression of CAD. We investigated the relationships between the level of circulating CD34/KDR(+) EPCs and CD133/KDR(+) EPCs, brachial FMD, and scores of depression and stress measured with the Depression Anxiety Stress Scales in 288 stable angina patients without major psychiatric disorders. As defined by the ≥75th percentile, 100 (35%) subjects had high depression score (≥8), and 84 (29%) subjects had high stress score (≥10). Subjects with high depression or stress score had significantly lower FMD (1.86±0.14 vs. 3.63±0.17%, p<0.001; 2.05±0.18 vs. 3.48±0.17%, p<0.001) and percentage of circulating CD34/KDR(+) EPCs (0.97±0.11 vs. 1.94±0.17%, p<0.001; 1.09±0.13 vs. 1.68±0.16%, p=0.005), but not CD133/KDR(+) EPCs (0.52±0.04 vs. 0.66±0.06%, p=0.057; 0.61±0.05 vs. 0.59±0.05%, p=0.833), as compared with subjects with normal depression or stress score. Multivariate regression analysis indicated that high depression score (OR 1.09, 95% CI: 1.04-1.15, p<0.001), but not stress score or percentage of circulating EPCs, independently predicted impaired brachial FMD. In conclusions, our results demonstrated that in stable angina patients without major psychiatric disorders, a high depression or stress score was related to attenuated brachial FMD and depletion of circulating EPCs. However, only the depression score, but not the stress score or the level of EPCs, was an independent predictor for decreased brachial FMD.

Delayed flow-mediated vasodilation and carotid atherosclerosis

BACKGROUND

In a previous study, we identified temporally distinct postischaemic flow-mediated dilation (FMD) patterns comparing the standard clinical measurement time of 50s postcuff release with measurement at 2 min. The comparison revealed a cohort with the highest FMD at 50s (Early FMD), another cohort with the highest FMD at 2 min (Late FMD) and a third cohort with no FMD (Absent FMD). The aim of this study was to examine whether these temporally distinct FMD patterns associated with different degrees of carotid atherosclerosis.

MATERIALS AND METHODS

One hundred and twenty-four free-living white subjects, participating in a cardio-vascular disease prevention campaign, were enrolled. FMD was measured at 50s, 2 min and 3 min after forearm ischaemia. The intima-media thickness (IMT) of the common carotid artery was measured, and the artery was evaluated for the presence and number of carotid plaques.

RESULTS

Fifty-seven subjects had Early FMD, 34 had Late FMD and 33 had Absent FMD. The three groups were comparable for age, sex and cardiovascular risk factors. The number of plaques in the carotid arteries, and IMT, increased progressively from Early, to Late, and to Absent FMD (P < 0·03), indicating that the FMD pattern is an independent predictive variable for IMT and carotid atherosclerosis.

CONCLUSIONS

The present study demonstrates that temporal patterns associated with the degree of atherosclerosis of the carotid arteries. Patients with delayed vasodilation (Late FMD) had a higher degree of atherosclerosis than those with early vasodilation (Early FMD), and subjects with no postischaemic vasodilation (Absent FMD) had the most atherosclerosis.

Flow-mediated dilation and cardiovascular risk prediction: a systematic review with meta-analysis

BACKGROUND

Flow-mediated dilation (FMD) is an accepted technique to quantify endothelial function and has shown to have prognostic value for future cardiovascular disease (CVD). The predictive strength of FMD in CVD patients compared to populations not diagnosed for CVD warrants further investigation. We systematically reviewed prospective studies that investigated the association between brachial FMD and future cardiovascular events, with particular focus on the role of underlying health status.

METHODS

To obtain eligible studies, several literature databases were systematically searched through March 2011. Pooled overall risk estimates were calculated separately for continuous risk estimates for CVD (per 1% higher FMD) and for categorical risk estimates for CVD (having high vs. low FMD), based on random-effects models.

RESULTS

A total of 23 studies including 14,753 subjects were eligible for inclusion in the meta-analysis. For studies reporting continuous risk estimates, the pooled overall CVD risk was 0.92 (95%CI: 0.88; 0.95) per 1% higher FMD. The observed association seemed stronger (P-value<0.01) in diseased populations than in asymptomatic populations (0.87 (95%CI: 0.83; 0.92) and 0.96 (95%CI: 0.92; 1.00) per 1% higher FMD, respectively). For studies reporting categorical risk estimates, the pooled overall CVD risk for high vs. low FMD was similar in both types of populations, on average 0.49 (95%CI: 0.39; 0.62).

CONCLUSIONS

Our findings show that brachial FMD is inversely associated with future CVD events, with some indications for a stronger relation in diseased populations. Endothelial dysfunction may be considered relevant for classifying subjects in terms of CVD risk.

The incremental value of brachial flow-mediated dilation measurements in risk stratification for incident cardiovascular events: a systematic review

Abstract Adequate risk assessment for cardiovascular disease (CVD) is essential as a guide to initiate drug treatment. Current methods based on traditional risk factors could be improved considerably. Although brachial flow-mediated dilation (FMD) predicts subsequent cardiovascular events, its predictive value on top of traditional risk factors is unknown. We performed a systematic review to evaluate the incremental predictive value of FMD on top of traditional risk factors in asymptomatic individuals. Using PubMed and reference tracking, three studies were identified that reported on the incremental value of FMD using change in the area under the curve (AUC). Two large cohort studies found no improvement in AUC when FMD was added to traditional risk prediction models, whereas one small case-control study found an improvement. One study used the net reclassification improvement (NRI) to assess whether FMD measurement leads to correct risk stratification in risk categories. Although this study did not find an improvement in AUC, the NRI was statistically significant. Based on the reclassification results of this study, FMD measurement might be helpful in risk prediction. Evidence supporting the use of FMD measurement in clinical practice for risk stratification for CVD on top of traditional risk factors is limited, and future studies are needed.

Systemic vascular function, measured with forearm flow mediated dilatation, in acute and stable cerebrovascular disease: a case-control study

Background

Acute ischaemic stroke is associated with alteration in systemic markers of vascular function. We measured forearm vascular function (using forearm flow mediated dilatation) to clarify whether recent acute ischaemic stroke/TIA is associated with impaired systemic vascular function.

Methods

Prospective case control study enrolling 17 patients with recent acute ischaemic stroke/TIA and 17 sex matched controls with stroke more than two years previously. Forearm vascular function was measured using flow medicated dilatation (FMD).

Results

Flow mediated dilatation was 6.0 ± 1.1% in acute stroke/TIA patients and 4.7 ± 1.0% among control subjects (p = 0.18). The mean paired difference in FMD between subjects with recent acute stroke and controls was 1.25% (95% CI -0.65, 3.14; p = 0.18). Endothelium independent dilatation was measured in six pairs of participants and was similar in acute stroke/TIA patients (22.6 ± 4.3%) and control subjects (19.1 ± 2.6%; p = 0.43).

Conclusions

Despite the small size of this study, these data indicate that recent acute stroke is not necessarily associated with a clinically important reduction in FMD.

Forearm vasodilator reactivity in homozygous carriers of the 9p21.3 rs1333049 G>C polymorphism

AIM

Recently, a novel susceptibility locus for coronary artery disease (CAD) has been identified on chromosome 9p21.3, linked to the single-nucleotide polymorphism (SNP) rs1333049 G>C. However, the physiological mechanism through which this locus confers an increased CAD-risk is still unknown. The aim of the present case-control study was to test whether this chromosome 9p21.3 locus, represented by the rs1333049 variant, is associated with altered vasodilator resistance vessel function in healthy young volunteers.

DESIGN AND RESULTS

A total of 97 healthy male volunteers were screened for homozygous carriers of either the G- or the C-allele, the minor allele in European populations. Forearm blood flow (FBF) reactivity to acetylcholine (ACh) and glycerol trinitrate (GTN) was then studied in 10 C/C-genotype carriers compared with 10 control subjects harbouring the G/G-genotype. FBF responses to ACh and GTN were reduced in subjects homozygous for the C-allele of the rs1333049 SNP (P < 0.05). FBF reactivity to the highest dose of ACh and GTN was 95% and 74% lower when compared with control subjects with the G/G-genotype.

CONCLUSION

Our study revealed a functional impairment in forearm artery vasodilator resistance in carriers of the rs1333049 C/C-genotype, thus providing evidence for a first physiological functional link underlying the genetic association of the 9p21.3 locus with an increased cardiovascular risk.

Stepwise positive association between APOA5 minor allele frequencies and increasing plasma triglyceride quartiles in random patients with hypertriglyceridemia of unclarified origin

Apolipoprotein A5 (ApoA5) gene and its protein product play a central role in the complex regulation of circulating triglyceride levels in humans. Naturally occurring variants of the apolipoprotein A5 gene have been associated with increased triglyceride levels and have been found to confer risk for cardiovascular diseases. In our study, four polymorphisms, the T-1131C, IVS3+G476A, T1259C, and C56G alleles of APOA5 were analyzed in a total of 436 patients by polymerase chain reaction-restriction fragment length polymorphism methods. The randomly selected patients were classified into four quartile (q) groups based on triglyceride levels (q1: TG<1.31 mmol/l; q2: 1.31-2.90 mmol/l; q3: 2.91-4.85 mmol/l; q4: TG>4.85 mmol/l). We observed significant stepwise increasing association between the four APOA5 minor allele carrier frequencies and plasma triglyceride quartiles: -1131C (q1: 4.44%; q2: 8.95%; q3: 12.9%; q4: 20.6%), IVS3 + 476A (q1: 4.44%; q2: 5.79%; q3: 11.1%; q4: 19.7%), 1259C (q1: 4.44%; q2: 6.84%; q3: 11.1%; q4: 20.6%) and 56G (q1: 5.64%; q2: 6.31%; q3: 11.16%; q4: 11.9%). The serum total cholesterol and high density lipoprotein-cholesterol levels also showed allele-dependent differences in the quartiles. The findings presented here revealed a special arrangement of APOA5 minor alleles in patients with different serum triglyceride ranges in Hungarians.

Paradoxical association of C-reactive protein with endothelial function in rheumatoid arthritis

BACKGROUND

Within the general population, levels of C-reactive protein (CRP) are positively associated with atherosclerotic cardiovascular disease (CVD). Whether CRP is causally implicated in atherogenesis or is the results of atherosclerosis is disputed. A role of CRP to protect endothelium-derived nitric oxide (EDNO) has been suggested. We examined the association of CRP with EDNO-dependent vasomotor function and subclinical measures of atherosclerosis and arteriosclerosis in patients with raised CRP resulting from rheumatoid arthritis (RA).

METHODOLOGY/PRINCIPAL FINDINGS

Patients with RA (n = 59) and healthy control subjects (n = 123), underwent measures of high sensitivity CRP, flow-mediated dilation (FMD, dependent on EDNO), intima-media thickness (IMT, a measure of subclinical atherosclerosis) and aortic pulse wave velocity (PWV, a measure of arteriosclerosis). IMT and PWV were elevated in patients with RA compared to controls but FMD was similar in the two groups. In patients with RA, IMT and PWV were not correlated with CRP but FMD was positively independently correlated with CRP (P<0.01).

CONCLUSIONS/SIGNIFICANCE

These findings argue against a causal role of CRP in atherogenesis and are consistent with a protective effect of CRP on EDNO bioavailability.