Increased platelet alpha2B-adrenergic receptor gene expression in well-controlled hypertensives: the effect of arterial stiffness

Catecholamines play a major role in atherothrombotic mechanisms in essential hypertension. Alpha_2B-adrenergic receptors (α2B-ARs) are implicated in the pathophysiology of platelet aggregation. In this study, we evaluated platelet α2B-AR gene expression levels in patients with well-controlled essential hypertension compared with normal individuals and investigated their association with increased arterial stiffness. Fifty-nine patients with well-controlled essential hypertension (34 men, mean age 65 ± 9 years) and 26 normotensives (19 men, mean age 64 ± 8 years) were included in the study. For each patient, carotid-femoral pulse wave velocity (PWV) and carotid-radial PWV were evaluated. In addition, blood samples were obtained and platelets were isolated. The α2B-AR gene expression levels in platelets were examined by real-time polymerase chain reaction for each participant. Well-controlled hypertensive patients showed significantly higher gene expression levels of α2B-Rs in platelets compared with normotensives (34.7 ± 29.5 vs 17.6 ± 12.5, respectively, P = .005). Interestingly, we found that carotid-femoral PWV and carotid-radial PWV were positively correlated with platelet α2B-R gene expression levels (r = 0.59, P < .001, and r = 0.39, P = .002, respectively).Platelet α2B-R gene expression levels are increased in patients with well-controlled essential hypertension compared with normotensives and are correlated with increased PWV in those patients. Our data indicate an association of arterial stiffness and platelet α2B-Rs gene expression and indicate the need for further research.

Long-term serial changes in platelet activation indices following sirolimus elution and bare metal stent implantation in patients with stable coronary artery disease

BACKGROUND

Platelet activation is crucial in the development of stent thrombosis following percutaneous coronary intervention (PCI). We carried out a long-term assessment of multiple factors implicated in the thrombotic process and monitored markers of platelet activation after the implantation of sirolimus-eluting stents (SES) in patients with stable coronary artery disease (CAD). Additionally, we compared these findings with those after bare-metal stent (BMS) implantation.

METHODS

A cohort of 47 consecutive patients, aged <70 years, with severe stenosis (>70% narrowing of the lumen) of one major epicardial coronary artery and stable CAD underwent successful elective PCI. Patients were randomly allocated to SES (n = 25) or BMS (n = 22). Venous blood was obtained 24 hours before and 24 hours, 48 hours, 1 month, and 6 months after PCI for measurements of plasma levels of sP-selectin, von Willebrand Factor (vWF), fibrinogen, d-dimer, sCD40, factor VIII, b-thromboglobulin (b-TG) and platelet factor 4 (PF-4).

RESULTS

There were no significant differences between the two groups in levels of fibrinogen or d-dimers in peripheral blood. However, we observed a significant kinetic effect (p<0.001) and stent-effect (p<0.015) on vWF levels and a significant kinetic effect (p = 0.012) on factor VIII, sP-selectin (p = 0.04), b-TG (p<0.001), and PF4 (p = 0.016). A trend towards a significant stent effect on sCD40 was also detected (p = 0.06).

CONCLUSIONS

SES and BMS did not show significant differences in relationship to markers of platelet activation and coagulation in patients with stable CAD. Although some markers showed an increase after stent implantation, they returned to the initial levels 6 months later.

The growing role of echocardiography in interventional cardiology: The present and the future

As structural heart disease interventions continue to evolve to a sophisticated level, accurate and reliable imaging is required for pre-procedural selection of cases, intra-procedural guidance, post-procedural evaluation, and long-term follow-up of patients. Traditionally, cardiovascular procedures in the catheterization laboratory are guided by fluoroscopy and angiography. Advances in echocardiography can overcome most limitations of conventional imaging modalities and provide successful completion of each step of any catheter-based treatment. Echocardiography's unique characteristics rendered it the ideal technique for percutaneous catheter-based procedures. The purpose of this review is to demonstrate the use of the most common and up-to-date echocardiographic techniques in recent non-coronary percutaneous interventional procedures, underlining its inevitable and growing role, as well as illustrating areas of weakness and limitations, and to provide future perspectives.

Asymptomatic versus symptomatic episodes in patients with paroxysmal atrial fibrillation via long-term monitoring with implantable loop recorders

BACKGROUND

The presentation of atrial fibrillation (AF) varies remarkably, from totally asymptomatic to symptomatic patients, while the same individual may present symptomatic and asymptomatic episodes. We aimed to identify electrocardiographic differences between symptomatic and asymptomatic episodes and to find parameters related to the appearance of symptoms.

METHODS

Thirty consecutive patients (age 66.9±10years) with paroxysmal AF received an implantable loop recorder. Three types of episodes were defined: asymptomatic (ASx), symptomatic (Sx), and mixed asymptomatic-symptomatic (AS-Sx). The heart rate (HR) and heart rate variability (HRV) were recorded during the first 2min of each ASx or Sx episode, and during the first 2min of both the symptomatic and asymptomatic periods in AS-Sx.

RESULTS

Eighty-two episodes from twenty-five patients were evaluated. Mean HR was 142.48±25.84bpm for Sx and 95.71±19.29bpm for ASx (p<0.001). Mean HRV was 92.62±42.29ms for Sx and 150.06±49.68ms for ASx (p<0.001). In AS-Sx, mean HR was 102.91±24.54bpm for the asymptomatic and 141.88±23.43bpm for the symptomatic period (p<0.001). Mean HRV was 173.55±61.30ms for the asymptomatic and 87.33±30.65ms for the symptomatic period (p=0.003). There were no significant correlations between patients' characteristics and the clinical presentation of the arrhythmia.

CONCLUSIONS

The ASx were characterized by a lower HR and higher HRV compared to Sx. In As-Sx, the asymptomatic period was characterized by a lower HR and higher HRV compared to the symptomatic. These findings suggest a possible contribution of variations in the autonomic nervous system activity to the perception of the arrhythmia.

Early Effects of Simvastatin versus Atorvastatin on Oxidative Stress and Proinflammatory Cytokines in Hyperlipidemic Subjects

The authors investigated the time-dependent action of atorvastatin and simvastatin on oxidative stress and cytokine levels immediately after the start of treatment. These factors play a role in endothelial dysfunction. Hyperlipidemic patients (n=132) were assigned to treatment with 40 mg atorvastatin, 40 mg simvastatin, or placebo. Blood samples were taken before, 2 hours, 24 hours, 7 days, and 3 weeks after the administration of the statin or placebo to evaluate serum concentrations of total peroxides (TP), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-a) and soluble intercellular vascular adhesion molecule 1 (sICAM 1). In the atorvastatin group the TP changes were significantly different at 2 hours and 24 hours (p=0.005), whereas in the simvastatin group there was a gradual, more or less linear decline in TP until 7 days (p=0.006) and then a plateau. Simvastatin exhibited a faster statistically significant decrease over time in IL-6 and sICAM 1 levels (at 7 days, p=0.014 and p=0.001, respectively). TNF-a demonstrated a faster linear trend in the simvastatin group, but the significant effect appeared late (p=0.006). Both simvastatin and atorvastatin exerted early beneficial effects on oxidative stress, proinflammatory cytokines, and endothelial activation in hyperlipidemic subjects. These effects became significant 2 hours following the initiation of therapy.

Long-term clinical outcomes in implantable cardioverter defibrillator recipients on the island of Crete

PURPOSE

The aim of the current study is to disseminate long-term "real-world" data on mortality and device therapies in primary and secondary prevention implantable cardioverter defibrillator (ICD) recipients on the island of Crete.

METHODS

We analyzed data for all consecutive patients who received an ICD in our tertiary university hospital from 1993 until December 2013. Follow-up visits were performed every 6 months or more frequently when indicated. Survival status was recorded, and all stored episodes during interrogation were registered and classified as appropriate or inappropriate.

RESULTS

In total, 854 patients received an ICD; 623 (73%) for primary and 231 (27%) for secondary prevention. Most of these patients (490) suffered from ischemic cardiomyopathy. During the mean follow-up of 12.4±7.8 years, 218 (25.5%) patients died; 19.7% in the primary prevention group (p=0.008) and 41.1% in the secondary prevention group. Overall, 248 patients (29%) received appropriate therapy; however, the percentage was significantly higher in the secondary prevention group (44.2%) than in primary prevention group (23.4%). The cumulative incidence of inappropriate therapies during the mean follow-up period was 11.6%. Lead-related complications were noted in 49 patients (5.7%), while only 13 patients (1.5%) suffered device-related infections.

CONCLUSIONS

The long-term data related to clinical outcomes in ICD recipients in our center are in accordance with those of other international centers and confirm the high efficacy and safety of these devices in preventing sudden cardiac death.

Essential hypertension in the pathogenesis of age-related macular degeneration: a review of the current evidence

Age-related macular degeneration (AMD) is one of the main causes of vision loss, especially in the elderly. The involvement of essential hypertension in its pathogenesis has been well covered in the literature since it was first recognized. Hemodynamic abnormalities appear to contribute to AMD, with the renin-angiotensin system playing a significant role. Many studies have demonstrated that high blood pressure is associated with lower choroidal blood flow and disturbed vascular homeostasis in these patients. In addition, AMD is characterized by abnormal neovascularization, to which angiotensin II and growth factors make a large contribution. Most epidemiological studies have found essential hypertension to be a risk factor for AMD. However, although all agree that the strongest predisposing factors are age and smoking, overall there is some inconsistency regarding the exact role of hypertension in its pathogenesis. In particular, there are no data in the literature to support the view that antihypertensive medication and the successful management of hypertension have a positive effect on the clinical outcome of AMD. This reinforces the data indicating that the cause of AMD is multifactorial and suggests that, although essential hypertension probably plays a role, in itself it is unlikely to be a major contributor to the future occurrence of AMD.

Healthy aging and myocardium: A complicated process with various effects in cardiac structure and physiology

It is known that there is an ongoing increase in life expectancy worldwide, especially in the population older than 65years of age. Cardiac aging is characterized by a series of complex pathophysiological changes affecting myocardium at structural, cellular, molecular and functional levels. These changes make the aged myocardium more susceptible to stress, leading to a high prevalence of cardiovascular diseases (heart failure, atrial fibrillation, left ventricular hypertrophy, coronary artery disease) in the elderly population. The aging process is genetically programmed but modified by environmental influences, so that the rate of aging can vary widely among people. We summarized the entire data concerning all the multifactorial changes in aged myocardium and highlighting the recent evidence for the pathophysiological basis of cardiac aging. Keeping an eye on the clinical side, this review will explore the potential implications of the age-related changes in the clinical management and on novel therapeutic strategies potentially deriving from the scientific knowledge currently acquired on cardiac aging process.

Endothelial progenitor cells as markers of severity in hypertrophic cardiomyopathy

AIMS

Endothelial progenitor cells (EPCs) are bone marrow-derived cells that are mobilized into the circulation to migrate and differentiate into mature endothelial cells contributing to post-natal physiological and pathological neovascularization. In this study, we evaluated circulating EPCs in patients with hypertrophic cardiomyopathy (HCM) and examined a potential association with clinical parameters of the disease.

METHODS AND RESULTS

We included 40 HCM patients and 23 healthy individuals. Using flow cytometry we measured EPCs in peripheral blood as two subpopulations of CD45-/CD34+/VEGFR2+ and CD45-/CD34+/CD133+ cells. Circulating CD45-/CD34+/VEGFR2+ cells were significantly increased in HCM patients in comparison with the controls (0.000238 ± 0.0003136 vs. 0.000057 ± 0.0001316, respectively, P = 0.002). However, there was no significant difference in the number of circulating CD45-/CD34+/CD133+ cells (0.003079 ± 0.0033288 vs. 0.002065 ± 0.0022173, respectively, P = 0.153). The CD45-/CD34+/VEGFR2+ subpopulation revealed a moderate correlation with LV mass index (r = 0.35, P = 0.026), while both EPC subpopulation levels showed strong positive correlations with th E/e' ratio (r = 0.423, P = 0.007 for CD45-/CD34+/VEGFR2+ and r = 0.572, P < 0.001 for CD45-/CD34+/CD133+).

CONCLUSION

HCM patients showed an increased mobilization of EPCs compared with healthy individuals that correlated with diastolic dysfunction. Our findings may open up new dimensions in the pathophysiology, prognostication, and treatment of HCM.

Hypertrophic and antihypertrophic microRNA levels in peripheral blood mononuclear cells and their relationship to left ventricular hypertrophy in patients with essential hypertension

MicroRNAs regulate several aspects of physiological and pathologic cardiac hypertrophy, and they represent promising therapeutic targets in cardiovascular disease. We assessed the expression levels of the microRNAs miR-1, miR-133a, miR-26b, miR-208b, miR-499, and miR-21, in 102 patients with essential hypertension and 30 healthy individuals. All patients underwent two-dimensional echocardiography. MicroRNA expression levels in peripheral blood mononuclear cells were quantified by real-time reverse transcription polymerase chain reaction. Hypertensive patients showed significantly lower miR-133a (5.06 ± 0.50 vs. 13.20 ± 2.15, P < .001) and miR-26b (6.76 ± 0.53 vs. 9.36 ± 1.40, P = .037) and higher miR-1 (25.99 ± 3.07 vs. 12.28 ± 2.06, P = .019), miR-208b (22.29 ± 2.96 vs. 8.73 ± 1.59, P = .016), miR-499 (10.06 ± 1.05 vs. 5.70 ± 0.91, P = .033), and miR-21 (2.75 ± 0.15 vs. 1.82 ± 0.20, P = .002) expression levels compared with healthy controls. In hypertensive patients, we observed significant negative correlations of miR-1 (r = -0.374, P < .001) and miR-133a (r = -0.431, P < .001) and significant positive correlations of miR-26b (r = 0.302, P = .002), miR-208b (r = 0.426, P < .001), miR-499 (r = 0.433, P < .001) and miR-21 (r = 0.498, P < .001) expression levels with left ventricular mass index. Our data reveal that miR-1, miR-133a, miR-26b, miR-208b, miR-499, and miR-21 show distinct expression profiles in hypertensive patients relative to healthy individuals and they are associated with clinical indices of left ventricular hypertrophy in hypertensive patients. Thus, they may be related to heart hypertrophy in hypertensive patients and are possibly candidate therapeutic targets in hypertensive heart disease.

Alterations in the expression of genes related to contractile function and hypertrophy of the left ventricle in chronically paced patients from the right ventricular apex

AIM

Long-term right ventricular apical (RVA) pacing may lead to left ventricular (LV) remodelling and heart failure. This study assessed changes in the expression of genes regulating LV contractile function and hypertrophy, after permanent RVA pacing and investigated whether such changes proceed or even predict LV remodelling.

METHODS AND RESULTS

We enrolled 52 consecutive patients (age 79.1 ± 7.7 years, 34 males) who underwent pacemaker implantation for bradycardic indications: Group A, 24 individuals with atrioventricular conduction disturbances and group B, 28 patients with sinus node disease. In group A, peripheral blood mRNA levels of gene sarcoplasmic reticulum calcium ATPase decreased at 3, 6, and 12 months' follow-up, while α-myosin heavy chain (MHC) decreased and β-MHC increased until 6 months follow-up. In this group, 25% of patients demonstrated significant LV remodelling. At 4 years, LV end-systolic diameter increased from 29.67 ± 3.39 mm at baseline to 35.38 ± 4.22 mm, LV end-diastolic diameter increased from 50 ± 4.95 to 56.71 ± 5.52 mm, and ejection fraction declined from 63.04 ± 10.22 to 52.83 ± 10.81%. Early alterations in gene expression were associated with a deterioration in LV function and geometry that became apparent months later. In group B, echocardiographic indexes and mRNA levels of the evaluated genes demonstrated no statistically significant changes.

CONCLUSIONS

Permanent RVA pacing in patients with preserved ejection fraction is associated with alterations in the expression of genes regulating LV contractile function and hypertrophy, measured in the peripheral blood. These alterations are traceable at an early stage, before echocardiographic changes are apparent and are associated with LV remodelling that becomes evident in the long term.

Heart rate and B-blockade in stable coronary artery disease in Greece

INTRODUCTION

Heart rate (HR) is a strong prognostic indicator in patients with coronary artery disease (CAD). However, there is only limited evidence on HR and the use of b-blockers in patients with CAD in contemporary clinical practice.

METHODS

CLARIFY is an international, prospective, observational, longitudinal registry of outpatients with stable CAD, defined as prior myocardial infarction or revascularization procedure, evidence of coronary stenosis >50%, or chest pain associated with proven myocardial ischemia. A total of 33,283 patients from 45 countries were enrolled between November 2009 and July 2010; of these, 559 patients were enrolled in Greece (age 62.3 ± 10.6 years, 84.44% men).

RESULTS

HR measured by pulse was 68.3 ± 10.2 bpm and by electrocardiogram 67.6 ± 10.9, with an excellent correlation (r=0.91, p<0.001). Overall, 42.8% had HR70 bpm. B-blockers were prescribed in 74.2% of patients. Resting HR by pulse on b-blocker was 67.8 bpm and without b-blocker 69.6 bpm (p=0.069). HR70 bpm was independently associated with a lack of physical activity, higher systolic blood pressure, and a higher prevalence of asthma or chronic obstructive pulmonary disease and carotid artery disease.

CONCLUSION

Despite the use of HR lowering agents, the percentage of patients with HR70 bpm was high. It is likely that we can further improve HR control in Greek patients with stable CAD by both increasing the prescription of b-blockers and up-titrating their dose, as well as by using and up-titrating other available HR lowering agents.

Two-dimensional global and segmental longitudinal strain: are the results from software in different high-end ultrasound systems comparable?

To compare the peak global longitudinal myocardial strain (PGLS) and peak segmental longitudinal myocardial strain (PSLS) values by speckle-tracking echocardiography (STE) obtained using two different echocardiography devices. STE is an emerging quantitative ultrasound technique that allows an accurate evaluation of global and segmental myocardial function. However, there is a lack of standardization of the acquired data among different manufacturers. Sixty-three subjects, mean age 56.2±10.4 years, underwent complete echocardiographic studies with two different devices (Philips IE33 and General Electric VIVID E9) performed by the same operator. Thirty-one of them had known cardiac disease, with estimated left ventricular ejection fraction <50%, while 32 were free of any cardiovascular disease (control subjects). All images were digitally stored and analyzed using off-line post processing with QLAB 9 and EchoPAC 11 Software packages. PSLS and PGLS were calculated. A strong relationship between QLAB and EchoPAC was found for PGLS (r=0.91, P<0.001), PSLS-4 chamber (CH; r=0.79, P<0.001), PSLS-2CH (r=0.73, P<0.001), and PSLS-3CH (r=0.78, P<0.001) QLAB. Bland–Altman analysis showed absolute differences vs average of −0.16, −0.37, −0.21, and −0.16 for PGLS, PSLS-4CH, PSLS-2CH, and PSLS-apical long-axis views respectively. Segmental analysis showed a good agreement between the apical segments, whereas poor correlations were found for the basal segments. Receiver operating characteristic curve analysis showed that cutoff values for PGLS of −17.5 and −17.75% with Philips or GE systems gave a sensitivity and specificity of 93.5 and 87.5%, and 90 and 87.5%, respectively, in the discrimination of the patients from the controls. Both Philips and GE echo stations were found to give comparable results for PGLS, with approximately the same cutoff values, suggesting that their PGLS results may be interchangeable.

Circulating mesenchymal stem cells in patients with hypertrophic cardiomyopathy

BACKGROUND

This study examines the mobilization of mesenchymal stem cells (MSCs) in patients with hypertrophic cardiomyopathy (HCM) compared to healthy individuals. The pathogenesis of myocardial hypertrophy in HCM is not fully understood. MSCs are involved in the process of neovascularization, fibrosis, and ventricular wall remodeling.

METHODS AND RESULTS

We included 40 patients with HCM and 23 healthy individuals. Using flow cytometry, we measured MSCs in peripheral blood, as a population of CD45-/CD34-/CD90+ cells and also as a population of CD45-/CD34-/CD105+ cells. The resulting MSC counts were expressed as percentages of the total cells. Patients with HCM were found to have a greater percentage of circulating CD45-/CD34-CD34-/CD90+ cells compared to controls (0.0041±0.005% vs. 0.0007±0.001%, respectively, P<.001). No significant difference in circulating CD45-/CD34-/CD105+ cells in the peripheral blood was found between HCM patients and controls (0.016±0.018% vs. 0.012±0.014%, respectively, P=.4). Notably, circulating CD45-/CD34-/CD90+ cells were positively correlated with left ventricular mass index (r=0.54, P<.001).

CONCLUSIONS

Patients with HCM reveal an increased mobilization of MSCs compared to healthy individuals. Although further research is needed to reveal the clinical significance of our findings, our data open a new dimension in the pathophysiology of the disease and may indicate new future therapeutic possibilities.