Effects of nebivolol on platelet activation in hypertensive patients: A comparative study with metoprolol

The impact of SELP gene Thr715Pro polymorphism on sP-selectin level and association with cardiovascular disease in Saudi diabetic patients: A cross-sectional case-control study

Background

Cardiovascular diseases (CVD) are leading cause of mortality in patients with type 2 diabetes mellitus (T2DM). Increased soluble sP-selectin and 715Thr > Pro polymorphism were studied in CVD and T2DM, but association between them hasn't been explored in Saudi Arabia. We aimed to assess sP-selectin levels in T2DM and T2DM-associated CVD patients in comparison to healthy control cohort. Also, we sought to investigate relationship between Thr715Pro polymorphism and sP-selectin levels and disease state.

Methods

This is a cross-sectional case-control study. sP-selectin level (measured by Enzyme-linked immunosorbent assay) and prevalence of Thr715Pro polymorphism (assessed by Sanger sequencing) were investigated in 136 Saudi participants. The study comprised 3 groups: group1 included 41 T2DM patients; group 2 (48 T2DM patients with CVD), and group 3 (47 healthy controls).

Results

sP-selectin levels were significantly higher in diabetics and diabetics + CVD groups as compared to the corresponding control. In addition, results showed that the prevalence of 715Thr > Pro polymorphism is 11.75 % in the study population amongst the three study groups (9.55 % Thr/Pro, and 2.2 % Pro/Pro). No statistical difference was found between sP-selectin levels in subject carrying the wildtype genotype of this polymorphism and these who carry the mutant gene. There could be an association between this polymorphism and T2DM, whilst the polymorphism may protect diabetic patients from having CVD. However, odds ratio is not statistically significant in both cases.

Conclusion

Our study supports the previous researches' results that Thr715Pro is neither influencing the sP-selectin level nor the risk of CVD in T2DM patients.

Physical activity and risk of all-cause mortality in patients with stable angina pectoris: Effect modification by β-blocker treatment

Background

Physical activity (PA) influences sympathetic stimulation, platelet activation as well as vascular function, and has been associated with improved health outcomes in patients with coronary heart disease. β-blocker therapy reduces sympathetic activity and improves platelet and endothelial function. We investigated if β-blocker treatment modifies the association of self-reported PA with the risk of all-cause mortality.

Methods

A total of 2284 patients undergoing elective coronary angiography for suspected stable angina pectoris (SAP) were studied. Using Cox modeling, we examined associations between PA (categorized as 'sedentary/inactive', 'low', 'moderate', and 'high') and all-cause mortality according to β-blocker therapy.

Results

During a median follow-up of 10.3 years, 390 patients (17.1%) died. Higher PA was generally associated with a more favorable cardiovascular risk profile. Compared to the patients who were sedentary or inactive, the age and sex adjusted HRs (95% CI) for all-cause mortality were 0.89 (0.66-1.20), 0.73 (0.57-0.95) and 0.72 (0.55-0.95) in the low, moderate and high PA group, respectively. However, and notably, these risk estimates were 0.85 (0.60-1.20), 0.65 (0.47-0.89) and 0.58 (0.41-0.81) in β-blocker treated subjects vs. 1.00 (0.57-1.78), 0.96 (0.61-1.52) and 1.20 (0.74-1.95) in non-treated groups (P _interaction = 0.018). The results were essentially similar in the multivariable adjusted models.

Conclusions

In patients with suspected SAP, increased PA was associated with reduced mortality risk primarily in patients treated with β-blockers.

No obvious association exists between mean platelet volume and hypertension subtypes

Aims: To determine the association between mean platelet volume (MPV) and hypertension subtypes. Participants & results: 44,281 Chinese individuals were enrolled in this cross-sectional study. The mean blood pressure decreased with increasing MPV in females (p = 0.001) and increased MPV seemed to be a potential protective factor for isolated diastolic hypertension in models 1 and 2. The OR (CI) was 0.878 (0.789-0.976) for model 1 and 0.880 (0.789-0.981) for model 2 in males and 0.646 (0.495-0.841) for model 1 and 0.657 (0.503-0.858) for model 2 in females, when MPV was analyzed as a categorical variable. The OR (CI) was 0.947 (0.911-0.985) for Model 1 and 0.947 (0.910-0.985) for Model 2 in males, and 0.886 (0.807-0.973) for Model 1 and 0.892 (0.813-0.978) for Model 2 in females when MPV was analyzed as a continuous variable. However, the statistical difference of OR disappeared when we added blood-related covariates in Model 3. Conclusion: No obvious association exists between MPV and hypertension subtypes. Other blood parameters might have a greater impact on hypertension subtypes.

The Effect of Mean Platelet Volume/Platelet Count Ratio on Dipper and Non-Dipper Blood Pressure Status

Background and Objectives: The mean platelet volume (MPV) represents a possible marker of platelet activation. There is an association between the platelet count (PC) and inflammation and platelet reactivity. We assessed the association between the MPV/PC ratio and circadian alterations in blood pressure (BP). Material and Methods: One hundred and twenty subjects in total, 80 hypertensive subjects and 40 healthy subjects (controls), were enrolled in the study group. Twenty four hour ambulatory BP monitoring (ABPM) was applied to all subjects. According to ABPM results, the hypertensive subjects were separated into two groups, such as dippers (n = 40) and non-dippers (n = 40). In all subjects, the collection of venous peripheral blood samples was performed on admission for PC and MPV measurements. Results: The two groups exhibited similar clinical baseline characteristics. A significantly higher MPV/PC ratio was determined in non-dippers compared to that in dippers and normotensives. The higher MPV/PC ratio was observed in non-dippers in comparison with that in dippers and normotensives (0.046 ± 0.007 to 0.032 ± 0.004 fL/[10⁹/L]; 0.046 ± 0.007 to 0.026 ± 0.004 fL/[10⁹/L], p < 0.001, respectively). A receiver operating characteristic (ROC) curve analysis showed that the optimum cut-off value of the MPV/PC ratio for predicting non-dipping patterns in hypertensive patients was 0.036 (area under the curve [AUC]: 0.98, p < 0.001). According to the cut-off value, sensitivity and specificity were found to be 95% and 95%, respectively. Conclusions: The higher MPV/PC ratio was determined in non-dipper hypertensive subjects in comparison with that in dipper hypertensive subjects. An elevation of platelet activity and an increase in thrombus burden are reflected by an increase in the MPV/PC ratio. The MPV/PC ratio may underlie the increase in cardiovascular risk in non-dippers compared to that in dippers.

Potential Protective Role of Blood Pressure-Lowering Drugs on the Balance between Hemostasis and Fibrinolysis in Hypertensive Patients at Rest and During Exercise

In patients with hypertension, the triad represented by endothelial dysfunction, platelet hyperactivity, and altered fibrinolytic function disturbs the equilibrium between hemostasis and fibrinolysis and translates into a hypercoagulable state, which underlies the risk of thrombotic complications. This article reviews the scientific evidence regarding some biological effects of antihypertensive drugs, which can protect patients from the adverse consequences of hypertensive disease, improving endothelial function, enhancing antioxidant activity, and restoring equilibrium between hemostatic and fibrinolytic factors. These protective effects appear not to be mediated through blood pressure reduction and are not shared by all molecules of the same pharmacological class.

Neutrophil stunning by metoprolol reduces infarct size

The β1-adrenergic-receptor (ADRB1) antagonist metoprolol reduces infarct size in acute myocardial infarction (AMI) patients. The prevailing view has been that metoprolol acts mainly on cardiomyocytes. Here, we demonstrate that metoprolol reduces reperfusion injury by targeting the haematopoietic compartment. Metoprolol inhibits neutrophil migration in an ADRB1-dependent manner. Metoprolol acts during early phases of neutrophil recruitment by impairing structural and functional rearrangements needed for productive engagement of circulating platelets, resulting in erratic intravascular dynamics and blunted inflammation. Depletion of neutrophils, ablation of Adrb1 in haematopoietic cells, or blockade of PSGL-1, the receptor involved in neutrophil-platelet interactions, fully abrogated metoprolol's infarct-limiting effects. The association between neutrophil count and microvascular obstruction is abolished in metoprolol-treated AMI patients. Metoprolol inhibits neutrophil-platelet interactions in AMI patients by targeting neutrophils. Identification of the relevant role of ADRB1 in haematopoietic cells during acute injury and the protective role upon its modulation offers potential for developing new therapeutic strategies.

The relationship of mean platelet volume with microalbuminuriain type 2 diabetic patients

BACKGROUND/AIM

Activation and size of platelets have been suggested to be involved in the pathogenesis of vascular complications in diabetes mellitus. The purpose of the present study was to investigate the association of mean platelet volume with microalbuminuria in type 2 diabetic patients.

MATERIALS AND METHODS

Mean platelet volume levels were investigated in healthy participants and type 2 diabetic patients with and without microalbuminuria. After their mean platelet volume values were compared, correlation of mean platelet volume with sex, duration of diabetes, microalbuminuria, fasting blood glucose, hemoglobin A1c, creatinine clearance, and body mass index was examined.

RESULTS

Mean platelet volume levels were higher in all diabetic patients than those in controls. Mean platelet volume levels were highest in diabetics with microalbuminuria. The mean platelet volume levels had a positive correlation with microalbuminuria.

CONCLUSION

Mean platelet volume values of diabetic patients were higher than those of nondiabetics, the highest levels being in diabetics with microalbuminuria. Our results suggest that microalbuminuria might be related with mean platelet volume in diabetic patients.

Pharmacological modulation of fibrinolytic response - In vivo and in vitro studies

Fibrinolysis is an action of converting plasminogen by its activators, like tissue- or urokinase-type plasminogen activators (t-PA, u-PA), to plasmin, which in turn cleaves fibrin, thereby causing clot dissolution and restoration of blood flow. Endothelial cells release t-PA, prostacyclin (PGI2) and nitric oxide (NO), the potent factors playing a crucial role in regulation of the fibrinolytic system. Since blood platelets can release not only prothrombotic, but also antifibrinolytic factors, like plasminogen activator inhibitor type-1 (PAI-1), they are involved in fibrynolysis regulation. Therefore agents enhancing fibrinolysis can be preferred pharmacologicals in many cardiovascular diseases. This review describes mechanisms by which major cardiovascular drugs (renin-angiotensin-aldosterone system inhibitors, statins, adrenergic receptors and calcium channel blockers, aspirin and 1-methylnicotinamide) influence fibrinolysis. The presented data indicate, that the influence of these drugs on endothelium-blood platelets interactions via NO/PGI2 pathway is fundamental for its antithrombotic and profibrinolytic action. We also described new approaches for intravital confocal real-time imaging as a tool useful to investigate mechanisms of thrombus formation and the effects of drugs affecting haemostasis and mechanisms of their action in the circulation.

Influence of Different β-Blockers on Platelet Aggregation in Patients With Coronary Artery Disease on Dual Antiplatelet Therapy

INTRODUCTION

The use of β-blockers in the treatment of patients with coronary heart disease is associated with a decrease in the frequency of angina pectoris and mortality of patients. Due to the severity of the disease and previous cardiovascular interventions, many patients with coronary artery disease (CAD) use dual antiplatelet therapy to achieve greater inhibition of platelet aggregation. The influence of β-blockers on platelet aggregation in patients using antiplatelet therapy is not well understood.

OBJECTIVE

To examine the effect of different β-blockers on platelet aggregation in patients on dual antiplatelet therapy.

METHODOLOGY

The study included 331 patients who were treated at the Department of Cardiology, Clinical Center Kragujevac during 2011. Patients were divided into 4 groups depending on the type of β-blockers that were used (bisoprolol, nebivolol, metoprolol, and carvedilol). Platelet aggregation was measured using the multiplate analyzer and expressed through the value of adenosine diphosphate (ADP) test (to assess the effect of clopidogrel), ASPI test (to assess the effect of acetyl salicylic acid), TRAP test (to assess baseline platelet aggregation), and the ratio of ADP/TRAP and ASPI/TRAP ASPI/TRAP (ASPI - aranchidonic acid induced aggregation, TRAP - thrombin receptor activating peptide) representing the degree of inhibition of platelet aggregation compared to the basal value. In consideration were taken the representation of demographic, clinical characteristics, laboratory parameters, and cardiovascular medications between the groups.

RESULTS

Patients who used nebivolol had a significantly lower value of the ratio of ADP/TRAP (0.39 ± 0.30) compared to patients who used bisoprolol (0.48 ± 0.26; P = .038), and trend toward the lower values of ADP test (328.0 ± 197.3 vs 403.7 ± 213.2; P = .059), while there was no statistically significant difference in values of other laboratory parameters of platelet function between other groups.

CONCLUSION

Patients with CAD on dual antiplatelet therapy who used nebivolol had significantly lower levels of residual ADP-induced platelet aggregation compared to baseline than patients who used bisoprolol.

Anti-thrombotic effects of nebivolol and carvedilol: Involvement of β2 receptors and COX-2/PGI2 pathways

BACKGROUND

Third generation β-adrenolytics, such as selective β1 adrenoceptor antagonist nebivolol and non-selective β1/β2 and α1 adrenoceptor antagonist carvedilol, display beneficial nitric oxide (NO)-dependent vasodilator activities that contribute to their therapeutic efficacy. In the present work, we analyzed whether nebivolol and carvedilol, as well as other β-adrenolytics with similar pharmacological profiles (selective β1 adrenoceptor antagonist - atenolol and non-selective α/β adrenoceptor antagonist - labetalol), possess the ability to induce PGI2-dependent anti-thrombotic activity in vivo in normotensive rats.

METHODS

Anti-thrombotic effects of nebivolol and carvedilol were studied in vivo in anaesthetized rats with extracorporeal circulation superfusing collagen strips. We also assessed vasodilation induced by these drugs in isolated perfused guinea pig hearts according to Langendorff's procedures.

RESULTS

Nebivolol (both d- and l-isomers) (0.1-1mgkg(-1)) and carvedilol (1-3mgkg(-1)), but not atenolol (1mgkg(-1)) or labetalol (3mgkg(-1)), induced a dose-dependent and sustained anti-thrombotic response in rat model of thrombosis with extracorporeal circulation. The cyclooxygenase (COX)-2 inhibitors, rofecoxib (1mgkg(-1)) and indomethacin (5mgkg(-1)) abrogated this response, while l-NAME (5mgkg(-1)) had no significant effect. In the presence of β1/β2 adrenoceptor antagonist nadolol (1mgkg(-1)), but not in the presence of selective β1 adrenoceptor antagonist atenolol (4mgkg(-1)), anti-thrombotic responses to nebivolol, as well as carvedilol, were lost. Neither nebivolol nor carvedilol affected platelet aggregation in vitro, however both nebivolol and carvedilol induced NO-dependent vasodilation in guinea pig coronary circulation that was not dependent on β2 adrenoceptors.

CONCLUSIONS

We demonstrated for the first time that nebivolol and carvedilol, independently of their adrenergic receptor blocking activities, induced anti-thrombotic effects in vivo that involved β2 adrenoceptors and the activation of the COX-2/PGI2 pathway.

Effects of nebivolol on skin flap survival: A randomized experimental study in rats

BACKGROUND

Skin flaps are among the basic treatment options in the reconstruction of soft tissue defects. To improve skin flap survival, a variety of methods, including pharmacologic agents, have been investigated. The effectiveness of anticoagulants, antioxidants, anti-inflammatory drugs, and vasodilatory drugs in improving flap survival has been studied. Nebivolol is a new-generation selective β1-adrenoreceptor blocking agent that has vasodilatory, antithrombotic, antioxidative, and anti- inflammatory effects.

OBJECTIVE

The aim of this experimental study was to investigate the effects of nebivolol (50 mg/kg/d) on random pattern skin flap survival in rats.

METHODS

Male Wistar rats weighing 290 to 310 g were randomly divided into 2 groups-the nebivolol group and the control group. Random patterned, caudally-based, ~3 × 10-cm skin flaps were elevated on the back of each rat. In the nebivolol group, nebivolol 50 mg/kg/d (1 mL, of a racemic solution of nebivolol) was administered orally 2 days before surgery to reach steady-state drug blood concentrations and was continued for 6 days. In the control group, 1 mL/d of sterile saline solution was orally administered 2 days before surgery and was continued for 6 days. To observe the effects of nebivolol, cutaneous blood flow was examined using a laser Doppler flow-meter before and after surgery on days 1, 3, 5, and 7, and flap tissue, malondialdehyde (MDA) and glutathione (GSH) concentrations, and superoxide dismutase (SOD) activity were measured 7 days postsurgery. Flap viability was evaluated 7 days after surgery by measuring necrotic flap area and total flap area.

RESULTS

All 20 rats (nebivolol group, n = 10; control group, n = 10) survived throughout the study period. Mean (SD) MDA concentration was significantly lower in the nebivolol group than in the control group (69.25 [5.82] vs 77.67 [6.87] nmol/g tissue; P = 0.009). GSH concentration was significantly higher in the nebivolol group than in the control group (2.14 [0.15] vs 1.88 [0.22] nmol/mg tissue; P = 0.004). SOD activity was significantly greater in the nebivolol group than in the control group (49.28 [5.49] vs 42.09 [4.95] U/g tissue; P = 0.007). The percentage of the flap that was necrotic was significantly lower in the nebivolol group than in the control group (40.27 [4.08] vs 48.87 [6.35]; P = 0.007).

CONCLUSIONS

This small, experimental, in vivo animal study found that nebivolol was associated with reduced necrotic random pattern skin flap area. Further studies are needed to clarify these findings.

Both carvedilol and nebivolol may improve platelet function and prothrombotic state in patients with nonischemic heart failure

It is unclear whether carvedilol and nebivolol will produce different effects on platelet function and prothrombotic state in heart failure (HF). Thus, we compared their effects on these functions in patients with nonischemic HF. We included 61 patients with symptomatic nonischemic HF having ejection fraction ≤40%. The patients were randomized to carvedilol (n = 31) or nebivolol (n = 30). Analyses were made at baseline, 3, and 6 months. At 6 months, mean platelet volume (MPV) was significantly lowered by both carvedilol and nebivolol therapy. However, MPV tended to be lower in the carvedilol group (7.7 ± 1.0 vs 8.0 ± 0.7 fL, P = .05). Fibrinogen and d-dimer levels were significantly decreased in but comparable in both the groups. Carvedilol and nebivolol have similar beneficial effects on platelet function and prothrombotic state in patients with nonischemic HF.

Mean platelet volume and abnormal left ventricle geometric patterns in patients with untreated essential hypertension

Abnormal left ventricle (LV) geometric patterns are associated with a greater risk of hypertensive vascular complications. The mean platelet volume (MPV) reflects the platelet activity, and is associated with overall vascular mortality. Although association between MPV and LV hypertrophy in hypertensive patients has been investigated, relation between abnormal LV geometric patterns and MPV was not studied so far. The aim of this study is to investigate the relationship between MPV and abnormal LV geometric patterns in hypertensive patients. Measurements were obtained from 223 patients with untreated essential hypertension (Mean age = 52.1 ± 5.2 years). Four different geometric patterns (NG; normal geometry, CR; concentric remodelling, EH; eccentric hypertrophy, CH; concentric hypertrophy) were determined according to the LV mass index (LVMI) and relative wall thickness (RWth). MPV, high sensitive C-reactive protein (hsCRP) and other biochemical markers were measured in all patients. The highest MPV values were determined in CH group compared with NG, CR and EH groups (p < 0.05, for all). MPV values were similar among the NG, CR and EH groups (p > 0.05, for all). MPV was associated with age, glucose, hsCRP, RWth, LVMI and LV geometry in bivariate analysis (p < 0.05, for all). Age (β = 0.110, p = 0.033), LVMI (β = 0.471, p < 0.001) and hsCRP (β = 0.525, p < 0.001) were independent predictors of high MPV in multiple linear regression analysis. The highest MPV values were observed in the CH group. This result may be associated with increased inflammation and LV hypertrophy in this geometric pattern.

Nebivolol: impact on cardiac and endothelial function and clinical utility

Endothelial dysfunction is a systemic pathological state of the endothelium characterized by a reduction in the bioavailability of vasodilators, essentially nitric oxide, leading to impaired endothelium-dependent vasodilation, as well as disarrangement in vascular wall metabolism and function. One of the key factors in endothelial dysfunction is overproduction of reactive oxygen species which participate in the development of hypertension, atherosclerosis, diabetes, cardiac hypertrophy, heart failure, ischemia-reperfusion injury, and stroke. Because impaired endothelial activity is believed to have a major causal role in the pathophysiology of vascular disease, hypertension, and heart failure, therapeutic agents which modify this condition are of clinical interest. Nebivolol is a third-generation β-blocker with high selectivity for β1-adrenergic receptors and causes vasodilation by interaction with the endothelial L-arginine/ nitric oxide pathway. This dual mechanism of action underscores several hemodynamic qualities of nebivolol, which include reductions in heart rate and blood pressure and improvements in systolic and diastolic function. Although nebivolol reduces blood pressure to a degree similar to that of conventional β-blockers and other types of antihypertensive drugs, it may have advantages in populations with difficult-to-treat hypertension, such as patients with heart failure along with other comorbidities, like diabetes and obesity, and elderly patients in whom nitric oxide-mediated endothelial dysfunction may be more pronounced. Furthermore, recent data indicate that nebivolol appears to be a cost-effective treatment for elderly patients with heart failure compared with standard care. Thus, nebivolol is an effective and well tolerated agent with benefits above those of traditional β-blockers due to its influence on nitric oxide release, which give it singular hemodynamic effects, cardioprotective activity, and a good tolerability profile. This paper reviews the pharmacology structure and properties of nebivolol, focusing on endothelial dysfunction, clinical utility, comparative efficacy, side effects, and quality of life in general with respect to the other antihypertensive agents.

Mean platelet volume in patients with dipper and non-dipper hypertension

Patients with non-dipper hypertension are known to carry a high risk of cardiovascular complications. In this study, we hypothesized that non-dippers may be associated with platelet dysfunction and it can be determined by mean platelet volume (MPV). A total of 216 outpatients treated with antihypertensive drugs for at least 6 months were enrolled. Dipper and non-dipper patterns were detected and clinical, laboratory and ambulatory blood pressure recording data were matched between non-dipping and dipping groups. MPV was significantly higher in patients in non-dipping than dipping groups (p<0.001). In correlation analyses, MPV was negatively correlated with the rate of systolic and diastolic fall at night (p<0.001, r=-0.46) and (p<0.001, r=-0.43), respectively. Also MPV was correlated with nocturnal pulse pressure (p=0.001, r=0.22). Other variables were similar between non-dipping and dipping groups. The present study showed that MPV is higher in non-dipping than dipping hypertensive patients. Platelet activation or dysfunction probably is an alternative mechanism for increasing cardiovascular events in non-dippers.

Circulating levels of cell adhesion molecules in hypertension

Hypertension causes complications such as coronary atherosclerosis and thrombosis wherein inflammatory factors play significant role. In the present study inflammatory molecules such as cell adhesion molecules (CAMs); endothelial (E)-selectin, platelet (P)-selectin, intercellular CAM-1 (ICAM-1), vascular CAM-1 (VCAM-1) and platelet endothelial CAM-1 (PECAM-1) were analysed in subjects newly diagnosed with hypertension with no secondary cause against normotensive healthy individuals. In each group 57 subjects were recruited and soluble (s) levels of CAMs were analysed by ELISA. As compared to controls median of sE-selectin (49.2%, P=0.001), sP-selectin (54.3%, P=0.001), and sICAM-1 (18.9%, P=0.012) were significantly elevated in hypertensive subjects. Significant negative correlation was observed of sP-selectin (spearman rank correlation coefficient (rs) =-0.345, p=0.027) and sPECAM-1 (rs =-0.446, p=0.003) with age in hypertension group. Hypertension may increase expression of certain CAMs while younger hypertensives in addition are also at increased risk of atherothrombosis.

Platelet activation and inflammatory response in patients with non-dipper hypertension

OBJECTIVE

Non-dipper hypertensives had about three times the risk of atherosclerotic events than hypertensives whose blood pressure was >10% lower at night compared to daytime (dippers). Platelet activation and inflammatory response may derive from most atherosclerotic events. Mean platelet volume (MPV) is a determinant of platelet activation and high sensitive C-reactive protein (hs-CRP) is the best candidate assay to identify and monitor the inflammatory response. We aimed to determine whether MPV and hs-CRP levels are elevated in non-dipper patients compared to dippers and healthy controls. In addition, we tried to find out if MPV and CRP are related to each other or not in non-dipper hypertensives.

METHOD

The total 126 patients study group included 86 patients with hypertension and 40 healthy subjects (16 male, mean age; 51+/-4) as control. Ambulatory blood pressure monitoring was performed for all patients. Hypertensive patients were divided into two groups; 46 dipper patients (18 male, mean age; 50+/-9) and 40 non-dipper patients (17 male, mean age; 53+/-11). Clinical baseline characteristics were similar between groups. We measured mean platelet volume in a blood sample collected in EDTA tubes and high-sensitive CRP was measured by using BN2 model nephlometer.

RESULTS

Non-dipper patients demonstrated higher levels of MPV compared to dippers and normotensives (9.72+/-0.52 fl vs 9.38+/-0.33 fl and 8.92+/-0.42 fl, p<0.05, respectively). High-sensitive CRP levels were also significantly higher in non-dippers compared to dippers and normotensives (4.9+/-1.7mg/l vs 3.8+/-1.5mg/l and 2.7+/-0.8mg/l, p<0.05, respectively). There was significant positive correlation between MPV and CRP levels (p=0.002, r=0.482) in non-dipper hypertensives.

CONCLUSION

Our results suggest that patients with non-dipping tend to have increased platelet activation and inflammatory response. Increased platelet activation and inflammatory response could contribute to increase the atherosclerotic risk in non-dipper patients compared to dippers.

Nebivolol: a third-generation beta-blocker for hypertension

BACKGROUND

Nebivolol is a third-generation beta(1)-selective beta-blocker that is approved for the treatment of hypertension.

OBJECTIVE

This article reviews the clinical pharmacology of nebivolol and its efficacy and safety profile in clinical studies of hypertension (the US Food and Drug Administration-approved indication) and heart failure (off-label use).

METHODS

Pertinent articles were identified through searches of MEDLINE and Current Contents from 1966 through December 15, 2008, using the terms nebivolol, drug interaction, pharmacokinetics, and pharmacology. The reference lists of the identified publications were reviewed for additional references. Abstracts presented at meetings of the American Heart Association and the American Society of Hypertension from 2006 through 2008 were also reviewed. All human clinical trials were included, regardless of design.

RESULTS

Twelve published clinical trials were identified that evaluated the use of nebivolol in the management of hypertension; 1 was placebo controlled, 1 was placebo and active controlled, and 10 involved direct comparisons with other antihypertensive agents. Nebivolol was reported to be as effective in lowering blood pressure (BP) as other beta-blockers (atenolol and bisoprolol), angiotensin-converting enzyme inhibitors (lisinopril and enalapril), the angiotensin-receptor blocker telmisartan, and calcium channel blockers (nifedipine and amlodipine). No published studies were identified that evaluated the effect of nebivolol on long-term cardiovascular outcomes. In data from a study in heart failure, nebivolol was associated with a 14% reduction in all-cause mortality and cardiovascular hospitalization at 12 months (P < 0.05). In comparative clinical studies, nebivolol appeared to be well tolerated relative to the other antihypertensive agents studied. The most commonly reported adverse events with nebivolol were fatigue (4%-79%), headache (2%-24%), paresthesia (7%-13%), bradycardia (6%-11%), rhinitis (1%-7%), and dizziness (2%-5%). Because of differences in its pharmacologic properties, nebivolol may have potential advantages in patients who are unable to tolerate traditional beta-blockers (eg, patients with asthma or chronic obstructive pulmonary disease, or men who experience erectile dysfunction while taking antihypertensive therapy).

CONCLUSIONS

Nebivolol is a cardioselective beta-blocker that has been reported to be efficacious and well tolerated for achieving BP control in patients with hypertension. Preliminary evidence suggests a potential for reduced mortality in patients with heart failure.

Nebivolol: a highly selective beta1-adrenergic receptor blocker that causes vasodilation by increasing nitric oxide

Nebivolol (Bystolic) is a cardioselective beta 1 (beta(1))-adrenergic receptor blocker with endothelium-dependent vasodilating properties. The endothelium-dependent relaxation induced by nebivolol is blocked by inhibitors of nitric oxide synthase (NOS) and guanylate cyclase. Nebivolol also increases in vitro and in vivo nitric oxide (NO), which is an essential signaling molecule involved in the maintenance of cardiovascular homeostasis. This review summarizes the data involving nebivolol and NO bioavailability. Endothelium-dependent relaxation of blood vessels, which is impaired in hypertensive animals and humans, is reversed by nebivolol treatment. Animals exhibiting endothelial dysfunction also show an improvement in NO-cyclic guanosine monophosphate (cGMP) signaling and an increase in NO bioavailability when treated with nebivolol. When blood vessel and cultured endothelial cells from hypertensive animals are treated with nebivolol, there is a decrease in superoxide production and an increase in the expression and activity of endothelial NOS (eNOS). As a result of the increased bioavailability of NO, nebivolol also increases in vivo arterial distensibility, glomerular filtration rate, and renal plasma flow. In normotensive volunteers, nebivolol infusion increases the forearm blood flow, an effect that is blocked by inhibitors of NOS and restored by the NOS substrate, L-arginine. In hypertensive patients, chronic treatment with nebivolol improves endothelium-dependent vasodilation induced by acetylcholine and shear stress and reverses endothelium-dependent vasoconstriction. Furthermore, nebivolol displays distinct hemodynamic properties in patients that include improvements in stroke volume and a decrease in peripheral vascular resistance. These studies demonstrate that nebivolol produces endothelium-dependent vasodilation by increasing NO release, decreasing oxidative stress to increase NO bioavailability, or both. The NO-dependent vasodilatory action of nebivolol, coupled with its high beta(1)-adrenergic receptor selectivity, is unique among the clinically available beta-blockers and contributes to its efficacy and improved tolerability (e.g., less fatigue and sexual dysfunction) as an antihypertensive agent.

Beta-blockers: no longer an option for uncomplicated hypertension

Traditionally, beta-blockers, used as first-line agents to treat uncomplicated hypertension, were recommended by national and international guidelines despite a paucity of evidence regarding their cardiovascular benefit. However, evidence from recent trials and meta-analyses has questioned the use of beta-blockers as preferred agents. This article reviews the data available from clinical trials and argues that beta-blockers are less efficacious than other currently available antihypertensive agents for patients with uncomplicated hypertension.

Efficacy and tolerability of nebivolol compared with other antihypertensive drugs: a meta-analysis

BACKGROUND AND OBJECTIVE

Lowering BP to normal levels without quality of life deterioration is the most important means of reducing cardiovascular risk. Recent studies have challenged the position of beta-adrenoceptor antagonists (beta-blockers) as first-line antihypertensive drugs. Nebivolol is a third-generation, highly selective beta(1)-blocker that causes vasodilation through nitric oxide (NO) release. This meta-analysis investigates the efficacy and tolerability of nebivolol compared with other antihypertensive drugs and placebo in patients with hypertension.

METHODS

Twelve randomized controlled studies were included in which nebivolol 5 mg once daily was compared with the recommended clinical doses of other antihypertensive drugs (n = 9), placebo (n = 2), and both (n = 1). The clinical studies were selected after a MEDLINE search up to 2007 using the key words 'nebivolol' and 'hypertension.'

RESULTS

Antihypertensive response rates (the percentage of patients achieving target BP levels or a defined DBP reduction) were higher with nebivolol than with ACE inhibitors (odds ratio [OR] 1.92; p = 0.001) and all antihypertensive drugs combined (OR 1.41; p = 0.001) and similar to beta-blockers, calcium channel antagonists (CCAs) and the angiotensin receptor antagonist (ARA) losartan. Moreover, a higher percentage of patients receiving nebivolol achieved target BP levels compared with patients treated with losartan (OR 1.98; p = 0.004), CCAs (OR 1.44; p = 0.024), and all antihypertensive drugs combined (OR 1.35; p = 0.012). The percentage of patients experiencing adverse events did not differ between nebivolol and placebo; adverse event rates were significantly lower with nebivolol than losartan (OR 0.52; p = 0.016), other beta-blockers (OR 0.56; p = 0.007), nifedipine (OR 0.49; p < 0.001), and all antihypertensive drugs combined (OR 0.59; p < 0.001).

CONCLUSION

Results of previous pharmacokinetic studies suggest that nebivolol 5 mg may not conform completely to the definition of a classic beta-blocker demonstrating additional antihypertensive effect due to endothelial NO release-mediated vasodilation. This meta-analysis showed that nebivolol 5 mg achieved similar or better rates of treatment response and BP normalization than other drug classes and other antihypertensive drugs combined, with similar tolerability to placebo and significantly better tolerability than losartan, CCAs, other beta-blockers, and all antihypertensive drugs combined. Although not definitive, this meta-analysis suggests that nebivolol 5 mg is likely to have advantages over existing antihypertensives and may have a role in the first-line treatment of hypertension.

Nebivolol: pharmacologic profile of an ultraselective, vasodilatory beta1-blocker

Beta-blockers are well-established therapeutic agents in the treatment of hypertension and cardiovascular disease. However, these agents are highly heterogeneous. Beta-blockers differ in their ancillary pharmacologic properties, which are clinically important. Nebivolol is a highly selective beta(1)-adrenergic receptor blocker that induces vasodilation through stimulation of the endothelial nitric oxide/L-arginine pathway. As a racemic mixture of d- and l-enantiomers, nebivolol is highly lipophilic and rapidly absorbed. Nebivolol undergoes extensive hepatic metabolism through the cytochrome P450 2D6 (CYP2D6) system. As a result of genetic polymorphisms, CYP2D6 has variable activity, manifested by extensive and poor metabolizers of nebivolol. Time to maximum concentration is 0.5 to 2 hours, and half-life is 11 hours in extensive metabolizers; these values are about 3 times longer in poor metabolizers. Urinary and fecal excretion of unchanged nebivolol is less than 0.5% of the dose. Nebivolol has a unique hemodynamic profile of reduced systemic vascular resistance and increased left ventricular function. These properties are attributed to its vasodilating action and contrast with the hemodynamic effects of conventional beta-blockers. Nebivolol is thus a novel beta-blocker with several important pharmacologic properties that distinguish it from traditional beta-blockers. These unique properties may confer clinical benefits beyond simple blood pressure lowering.

Influence of Nebivolol and Metoprolol on Inflammatory Mediators in Human Coronary Endothelial or Smooth Muscle Cells. Effects on Neointima Formation After Balloon Denudation in Carotid Arteries of Rats Treated with Nebivolol

OBJECTIVE AND BACKGROUND

Inflammation plays a critical role in all stages of atherogenesis. Proliferating vascular smooth muscle cells (SMC) and endothelial cells (EC) enhancing the inflammatory response, both contribute to the progression of atherosclerosis. Anti-proliferative, anti-inflammatory and anti-oxidative therapy seems to be a promising therapeutic strategy. The aim of this study was to assess the anti-proliferative and anti-inflammatory effect of the beta-blocker nebivolol in comparison to metoprolol in vitro and to find out whether nebivolol inhibits neointima formation in vivo.

METHODS AND RESULTS

Real-time-RT-PCR revealed a decrease in VCAM-1, ICAM-1, PDGF-B, E-selectin and P-selectin mRNA expression in human coronary artery EC and SMC incubated with nebivolol for 72 hours while metoprolol did not have this effect. Nebivolol reduced MCP-1 and PDGF-BB protein in the culture supernatant of SMC and EC, respectively. Sprague-Dawley rats were treated with nebivolol for 0 or 35 days before and 28 days after carotid balloon injury. Immunohistological analyses showed that pre-treatment with nebivolol was associated with a decreased number of SMC layers and macrophages and an increased lumen area at the site of the arterial injury. The intima area was reduced by 43% after pre-treatment.

CONCLUSION

We found that nebivolol reduced the expression of proinflammatory genes in endothelial cells and vascular smooth muscle cells in vitro whereas metoprolol did not. In vivo, nebivolol inhibited neointima formation by reducing SMC proliferation and macrophage accumulation.