Pharmacological Mechanisms of Clinically Favorable Properties of a Selective β1-Adrenoceptor Antagonist, Nebivolol

Nebivolol is a racemic mixture of d- and l-enantiomers. The drug is characterized by beta(1)-adrenoceptor selectivity and long-acting beta-blockade exerted predominantly by d-enantiomer. Nebivolol is devoid of intrinsic sympathomimetic activity and has no relevant membrane stabilizing action. Antiproliferative properties of nebivolol were demonstrated in endothelial and smooth muscle cell cultures. Infusion of nebivolol causes a vasodilation in all vascular beds by endothelial-dependent mechanism involving stimulation of beta(3)-adrenoceptors as well as by endothelial-independent mechanism. Nebivolol possesses not only direct vasodilator properties but also augments the action of endothelium-dependent vasodilators. The antioxidant property of nebivolol can at least in part explain why treatment with this drug enhances eNOS activity and minimizes the reperfusion-induced myocardial injury. The systemic effects of nebivolol in humans have an unusual hemodynamic profile. In contrast to traditional beta-adrenoceptor antagonists, nebivolol reduces preload and afterload due to systemic vasodilation and improves arterial distensibility. At 5 mg daily nebivolol effectively reduces systolic and diastolic blood pressure over a 24-h period. During treatment with nebivolol arterial pressure follows the natural circadian rhythm. Trough-to-peak ratio for nebivolol is 0.9. It has been demonstrated in numerous placebo-controlled studies that exercise tolerance is not reduced during nebivolol therapy. By chronic administration to patients with left ventricular dysfunction nebivolol increases myocardial contractility. Nebivolol produced no significant changes in lipid levels, insulin sensitivity or glucose tolerance. These findings make nebivolol a promising therapeutic tool for the treatment of arterial hypertension and chronic heart failure.

Characterization of nitric oxide release by nebivolol and its metabolites

BACKGROUND

Nebivolol is a selective beta(1)-adrenergic receptor antagonist that causes a direct vasodilator effect attributed to the action on vascular nitric oxide (NO). This study aimed to investigate whether nebivolol or its metabolites induces NO production and to explore the mechanisms underlying this pharmacologic effect.

METHODS

Conductance and resistance arteries from Wistar-Kyoto rats (WKY) (n = 33) incubated with the fluorescent probe diaminofluorescein-2 (DAF-2) were stimulated with increasing concentrations of nebivolol or its enantiomers and metabolites, and NO release was histologically evaluated.

RESULTS

Nebivolol induced a dose-dependent increase in NO levels in the endothelium of both arteries. Levels of NO were significantly increased at 10(-6)mol/L and reached a plateau state at 10(-5)mol/L. Induction of NO is not a general action of beta-adrenoceptor antagonists, as atenolol had no effects. Nebivolol action on NO release was mainly caused by the D-isomer. Moreover NO production is also maintained after hepatic metabolism, as the three main metabolites of nebivolol were able to induce a significant increase in endothelial NO release. Finally, nebivolol-activated calcium mobilization is crucial to NO production.

CONCLUSION

Our study shows the effects of D-nebivolol and its metabolites on endothelial NO production in both conductance and resistance arteries, and clarifies that this effect is realized through a calcium-dependent mechanism.

[Effect of nebivolol on endothelial function in obese patients with hypertension]

The study aimed at assessing functional state of vessel endothelium using Doppler cardiography in patients with arterial hypertension and excessive weight under Nebivolol treatment. 15 overweight patients with hypertension disease who underwent Tselemayer-Sorensena test have been observed to assess endothelium-dependent and endothelium-independent vasodilatation. Positive influence of nebivolol on vessel endothelium was noted in the study.

The Influence of prolonged β-blockers treatment on male rabbit's sexual behavior and penile microcirculation

The aim of the study was to assess the effect of the prolonged intake of three beta-blocking drugs (propranolol, metoprolol and nebivolol) on the sexual behavior and penile microcirculation of rabbits. Drugs were administered p.o. for 9 weeks and every three weeks in each group (n=13) one subgroup (n=7) performed behavioral tests, whereas in the second subgroup (n=6) penile microcirculation was measured with a laser Doppler flowmeter. The copulation studies revealed significant impairment of sexual function only in the propranolol treated group. The measured behavioral parameters suggest that at a given dose propranolol affects more performance rather than arousal aspects of rabbits' sexual behavior. In the course of the whole study no significant difference was observed among groups in penile blood flow. The data indicate that among the beta-blockers given only propranolol interferes with sexual behavior, and that beta-blockers do not appear to have a negative effect on penile microcirculation.

Comparative effects of nebivolol and metoprolol on oxidative stress, insulin resistance, plasma adiponectin and soluble P-selectin levels in hypertensive patients

OBJECTIVES

To determine the effects of nebivolol on oxidative stress, insulin resistance, adiponectin and plasma soluble P-selectin levels in hypertensive patients in comparison with metoprolol.

MATERIAL AND METHODS

Eighty newly diagnosed hypertensive patients in grade 1 hypertension according to the European Society of Hypertension and European Society of Cardiology guidelines were enrolled in this prospective, blinded, randomized study. Seventy-two patients completed the study. After baseline assessment, each patient was randomly allocated to a 5 mg daily dose of nebivolol (n = 37, 20 male) or a 100 mg daily dose of metoprolol (n = 35, 18 male) and treated for 6 months. Blood pressure, heart rate, oxidative stress (malonyldialdehyde), homeostasis model assessment: insulin resistance, adiponectin and plasma soluble P-selectin levels were measured before and after treatment.

RESULTS

At the end of treatment, nebivolol and metoprolol significantly decreased blood pressure and heart rate, with a more pronounced bradycardic effect of metoprolol. Nebivolol, but not metoprolol, significantly lowered oxidative stress (P = 0.03), the insulin resistance index (P = 0.003) and plasma soluble P-selectin levels (P = 0.008), and increased adiponectin levels (P = 0.04).

CONCLUSION

Nebivolol, in contrast to metoprolol, improved oxidative stress, insulin sensitivity, decreased plasma soluble P-selectin and increased adiponectin levels in hypertensive patients. These beneficial effects of nebivolol may contribute to a reduction in cardiovascular risk in hypertensive patients.

[Effects of nebivolol on endothelial dysfunction in patients with diastolic dysfunction of left ventricle]

The aim of our research was to assess the role of vasoactive factors of endothelium (NO and endothelin-1) during diastolic dysfunction of the left ventricle and to determine the effects of nebivolol in the early treatment period of endothelial dysfunction. In the investigation were included 36 male patients (mean age 49+/-6 years) with LVDD due to CAD (22 patients) and essential hypertension (14 patients) as well as in 18 male patients (control group, 12 patients with CAD and 6 with hypertension) without LVDD of matched age, who underwent 2 week treatment with 5 mg nebivolol (Nebilet, Berlin-Chime) . The endothelial dysfunction was assessed by (a) a noninvasive method, brachial artery ultrasound during reactive hyperemia, measured by flow-mediated vasodilatation (FMD), which indirectly reflects the amount of NO and (b) measurement of the amount of ET-1 in the plasma by method of an enzyme-linked immunoassay (ELISA). According to the results of our studies FMD (%) was increased by 73% among the patients with DD of LV whereas among the patients without DD was increased by 66% (p<0,05). Furthermore, statistically none significant decrease of endothelin-1 levels were observed and no difference was found among the groups of patients. Importantly, statistically significant increase of early ventricular filling was found: E/A ratio with Doppler echocardiography at the end of 2 week period treatment reached 1,10+/-0,04 vs. 0,92+/-0,01 before the treatment (p<0,05). Positive correlation was found between FMD (%) and the relaxation capability of the left ventricle (r=0,38, p<0,05). Based on these results we can conclude that endothelial dysfunction might be indicator of LVDD, and by treating the former we can prevent the diastolic dysfunction.

Effect of treatment with nebivolol on parameters of oxidative stress in type 2 diabetics with mild to moderate hypertension

AIM

The aim of this study was to examine the effect of the cadioselective B(1)-adrenoceptor blocker nebivolol on glycaemic control, lipid profile and markers of oxidative stress in patients with type 2 diabetes over a 6-month period.

METHODS

Twenty-six patients with mild to moderate hypertension (140-160 mmHg systolic, 90-105 mmHg diastolic) confirmed on 24-h blood pressure monitoring, were treated with nebivolol 5 mg daily for 6 months. Total serum cholesterol, triglycerides, high-density lipoprotein (HDL) cholesterol and low-density lipoprotein (LDL) subfractions, lipid hydroperoxides (LHPs) and total antioxidant capacity (TAC) were measured before and after 6 months of treatment.

RESULTS

Nebivolol, as expected, reduced mean daytime systolic and diastolic pressures on ambulatory monitoring (149 +/- 9 to 140 +/- 13 mmHg, P = 0.02 and 84 +/- 7 to 77 +/- 9 mmHg, P < 0.001). There were no significant changes in serum cholesterol or triglycerides following treatment but a significant increase in HDL cholesterol was noted (1.12 +/- 0.19 to 1.25 +/- 0.36 mmol/L, P = 0.008). Patients showed a highly significant reduction in TAC from 501 +/- 57 to 422 +/- 29 trolox equivalent (P < 0.001). Baseline LHPs were very high and showed no significant change over the 6-month period (18.7 +/- 7.4 and 18.7 +/- 10.9 micromol/L). The LDL score increased significantly from 1.7 +/- 0.7 to 2.3 +/- 0.7 (P = 0.0002) at 6 months suggesting a change to a more atherogenic lipid profile. Neither weight nor glycaemic control changed during treatment.

CONCLUSION

Nebivolol appears to be lipid neutral and may even have a positive effect on HDL cholesterol. Despite this it may promote the formation of potentially atherogenic LDL subfractions possibly as a result of reduced antioxidant defences. Further studies are needed to clarify the changes observed in parameters of oxidative stress.

Influence of nebivolol on endothelial dysfunction in salt-sensitive hypertension

The study was aimed to assess influence of nebivolol (nebilet) on endothelial factors (NO and endothelin1) during treatment of salt-sensitive hypertensive patients. A total of 40 patients (18 females and 22 males, mean age 53,1+/-1,58 yrs) with mild (I stage) arterial hypertension (with diastolic pressure 90-99 mm Hg and/or systolic pressure 140-159 mm Hg) were studied. Twelve age matched healthy subjects (4 women and 8 males) composed control group. Salt sensitivity was detected by M. Weir (1993) method. Patients were divided in two groups: salt sensitive hypertension (group I, 16 patients) and salt-resistant hypertension (group II, 24 patients). Nebivolol (Nebilet, Berlin-Chemie, Germany) was administered to 25 patients in dosage of 5 mg once a day during two weeks. Our studies have showed that ET-1 plasma levels were significantly elevated in patients with essential hypertension, while NO was markedly reduced compared to control group. NO levels were slightly lower in salt-sensitive hypertensives than in salt-resistant patients (p>0,05). ET-1 levels expressed opposite changes: in patients with salt-sensitive hypertension ET-1 levels almost twice exceeded those of salt-resistant patients (p<0,01). After treatment with nebivolol NO plasma level in salt-sensitive hypertensives significantly increased in Group I and did not change significantly in salt-resistant patients. Only slight decrease in ET-1 levels was detected in both groups after taking nebilet. Nebilet (nebivolol) treatment has an influence only on NO levels and appears to be the most effective in salt-sensitive hypertension.

Beneficial effects of switching from beta-blockers to nebivolol on the erectile function of hypertensive patients

AIM

To investigate the effect of substituting beta-blockers with nebivolol on the erectile function of patients suffering from essential hypertension.

METHODS

Forty-four young and middle-aged men (31-65 years) with essential hypertension visited our outpatient clinic and took beta-blocker treatment (atenolol, metoprolol or bisoprolol) for more than 6 months. All the patients completed a questionnaire regarding erectile function (International Index for Erectile Function). Patients were then switched to an equipotent dose of nebivolol for 3 months and, at the end of this time period, filled out the same questionnaire.

RESULTS

Twenty-nine out of the 44 (65.9%) patients who took beta-blockers (atenolol, metoprolol or bisoprolol) had exhibited erectile dysfunction (ED). Their systolic and diastolic blood pressure did not change significantly with the treatment switch. In 20 out of these 29 (69%) patients, a significant improvement in the erectile function score was exhibited after 3 months of nebivolol administration, and in 11 of these 20 patients, erectile function was normalized.

CONCLUSION

Nebivolol seems to have a beneficial effect on ED (possibly due to increased nitric oxide availability); however, further prospective, randomized, placebo-controlled studies are needed to confirm the beneficial effects of nebivolol.

Endothelial beta3-adrenoreceptors mediate nitric oxide-dependent vasorelaxation of coronary microvessels in response to the third-generation beta-blocker nebivolol

BACKGROUND

The therapeutic effects of nonspecific beta-blockers are limited by vasoconstriction, thus justifying the interest in molecules with ancillary vasodilating properties. Nebivolol is a selective beta1-adrenoreceptor antagonist that releases nitric oxide (NO) through incompletely characterized mechanisms. We identified endothelial beta3-adrenoreceptors in human coronary microarteries that mediate endothelium- and NO-dependent relaxation and hypothesized that nebivolol activates these beta3-adrenoreceptors.

METHODS AND RESULTS

Nebivolol dose-dependently relaxed rodent coronary resistance microarteries studied by videomicroscopy (10 micromol/L, -86+/-6% of prostaglandin F2alpha contraction); this was sensitive to NO synthase (NOS) inhibition, unaffected by the beta(1-2)-blocker nadolol, and prevented by the beta(1-2-3)-blocker bupranolol (P<0.05; n=3 to 8). Importantly, nebivolol failed to relax microarteries from beta3-adrenoreceptor-deficient mice. Nebivolol (10 micromol/L) also relaxed human coronary microvessels (-71+/-5% of KCl contraction); this was dependent on a functional endothelium and NO synthase but insensitive to beta(1-2)-blockade (all P<0.05). In a mouse aortic ring assay of neoangiogenesis, nebivolol induced neocapillary tube formation in rings from wild-type but not beta3-adrenoreceptor- or endothelial NOS-deficient mice. In cultured endothelial cells, 10 micromol/L nebivolol increased NO release by 200% as measured by electron paramagnetic spin trapping, which was also reversed by NOS inhibition. In parallel, endothelial NOS was dephosphorylated on threonine(495), and fura-2 calcium fluorescence increased by 91.8+/-23.7%; this effect was unaffected by beta(1-2)-blockade but abrogated by beta(1-2-3)-blockade (all P<0.05).

CONCLUSIONS

Nebivolol dilates human and rodent coronary resistance microarteries through an agonist effect on endothelial beta3-adrenoreceptors to release NO and promote neoangiogenesis. These properties may prove particularly beneficial for the treatment of ischemic and cardiac failure diseases through preservation of coronary reserve.

Phosphodiesterase type 5 inhibitor sildenafil citrate does not potentiate the vasodilative properties of nebivolol in rat aorta

BACKGROUND

Sildenafil citrate (SIL) is contraindicated in patients with coronary heart disease who are treated with nitric oxide (NO) donators such as organic nitrates, as it potentiates NO-mediated vasodilation. The present study investigated whether SIL also affects the vasodilatory effects of nebivolol (NEB), a selective beta1-adrenoceptor blocker with an additional, endothelium-dependent NO-liberating property, in comparison to the combination SIL/glycerol trinitrate (GTN).

METHODS AND RESULTS

Experiments were performed in isolated vessel rings of rat aorta (Wistar rats, 8-12 weeks), which had been pre-contracted with phenylephrine (10(-5) M). Isometric tension was measured by a force transducer, and cumulative concentration-response curves were obtained for each drug. The rank order of vasodilatory potency as measured by the concentration needed to achieve 50% relaxation (EC50) was GTN (0.08 microM) > SIL (1.25 microM) > or = NEB (3.5 microM). In the presence of both therapeutic (1 nM) and high (1 microM) concentrations of SIL, vasodilation of GTN was potentiated as indicated by a significant increase in vasodilatory potency (EC50 GTN + low SIL: 0.019 microM, EC50 GTN + high SIL: 0.002 microM; both P < 0.01 vs. GTN). In contrast, SIL did not potentiate the vasodilatory effect of NEB (EC50 NEB + low SIL: 5.01 microM, EC50 NEB + high SIL: 3.2 microM; n.s. vs. NEB).

CONCLUSIONS

These data demonstrate that SIL does not potentiate NEB-induced vasodilation in vitro. These findings indicate that the interaction between SIL and NO-donators/organic nitrates does not apply to the NO-liberating properties of NEB. Our findings suggest that SIL may safely be used in hypertensive patients treated with NEB.

Effects of nebivolol in elderly heart failure patients with or without systolic left ventricular dysfunction: results of the SENIORS echocardiographic substudy

AIMS

The SENIORS trial recently demonstrated that nebivolol reduces the composite risk of all-cause mortality and cardiovascular hospital admission in elderly patients with chronic heart failure and, importantly, that ejection fraction does not influence the clinical effects of nebivolol. An echocardiographic substudy was designed to evaluate the effects of nebivolol on systolic and diastolic left ventricular (LV) function in patients stratified according to the presence or absence of systolic LV dysfunction.

METHODS AND RESULTS

The substudy randomized 112 patients in 29 European centres, of whom 104 were evaluable for the study; 43 had an ejection fraction (EF) <or=35% and 61 had an EF>35%. LV end-systolic volume (ESV), EF, mitral valve E/A ratio, and E-wave deceleration time were assessed at baseline and after 12 months. Echocardiograms were submitted to a core laboratory to perform quantitative analysis in blinded condition. In the group with EF</=35%, nebivolol reduced ESV (adjusted difference between treatments 25.8 mL, 95%CI: -46.6; -5.0, P=0.016) and improved EF (adjusted difference between treatments 4.6%, 95%CI: 1.3;7.9, P=0.008); no changes were observed in the E/A ratio or E-wave deceleration time. In EF>35% group, no significant changes in either systolic or diastolic parameters were observed.

CONCLUSION

In patients with heart failure and advanced systolic LV dysfunction, nebivolol reduces ventricular size and improves EF. The absence of detectable changes with standard echocardiography in patients with predominant diastolic heart failure questions the mechanism of benefit on morbidity/mortality in such patients.

Cardiovascular effects of nebivolol in spontaneously hypertensive rats persist after treatment withdrawal

OBJECTIVES

We observed previously that nebivolol treatment for 2 months reduced cardiovascular lesions in spontaneously hypertensive rats (SHR). Therefore, we investigated whether this beneficial effect is increased with a longer treatment, and its persistence after withdrawal.

METHODS

Male SHR were treated with 8 mg/kg per day of nebivolol (N-SHR) for 6 months. A separate group was also given identical treatment but they were then monitored for a further 3 months after drug withdrawal. SHR and Wistar-Kyoto rats (WKY) receiving vehicle were used as controls. Systolic blood pressure and heart rate were measured using the tail-cuff method. Left ventricular weight/body weight ratio was calculated as the hypertrophy index. Cardiac and vascular fibrosis was evaluated on sections stained with sirious red. Vascular reactivity was evaluated on aortic rings through acetylcholine and sodium nitroprusside responses. The effect of treatment on vascular structure was assessed by lumen diameter, wall thickness and medial cross-sectional area determination.

RESULTS

Blood pressure was reduced in N-SHR. After withdrawal it increased progressively, without reaching the values of the hypertensive controls. Cardiac hypertrophy and collagen content both in heart and aorta were significantly reduced, and these changes persisted after nebivolol suppression. Acetylcholine-induced relaxant response was improved by nebivolol and maintained after withdrawal. Medial thickness and cross-sectional area were significantly reduced in both conductance and resistance arteries, and these effects persisted after withdrawal.

CONCLUSION

The nebivolol antihypertensive effect was accompanied by an important reduction of hypertrophy and collagen deposition in both vascular and left ventricle tissue, which was maintained after a long period of therapy withdrawal.

Nebivolol

Nebivolol is a third-generation beta-adrenoceptor antagonist. It differs from other beta-adrenoceptor antagonists as it combines highly selective beta(1)-adrenoceptor antagonist properties with nitric oxide-mediated vasodilatory actions and beneficial effects on endothelial function. Nebivolol is approved in Europe and several other countries for the treatment of essential hypertension and in Europe for the treatment of stable mild or moderate chronic heart failure (CHF) in addition to standard therapies in elderly patients aged >or=70 years. Nebivolol is an effective antihypertensive agent and is well tolerated in patients with hypertension. The drug also effectively decreased the composite endpoint of mortality and cardiovascular hospital admission in elderly patients with CHF and was generally well tolerated in this population. Nebivolol should be considered as an alternative first-line treatment option for patients with uncomplicated mild to moderate essential hypertension and in elderly patients with CHF.

??-Adrenoceptor Antagonists in Elderly Patients with Chronic Heart Failure

Chronic heart failure (CHF) is a common and disabling condition with an incidence and prevalence that increase sharply with age. The median age of presentation of new heart failure cases is > 75 years. Effective treatments, including beta-adrenoceptor antagonists, have been proven in randomised, controlled trials. The average age in these placebo-controlled mortality and morbidity studies of beta-adrenoceptor antagonists in heart failure has, however, been < 63 years, and all patients with an ejection fraction > or = 40% were excluded. This lack of a representative sample of elderly patients with heart failure has raised concerns about extrapolating the available evidence for beta-adrenoceptor antagonists to a more elderly heart failure population. Beta-adrenoceptor antagonists may have a less beneficial effect or even an adverse effect in elderly heart failure patients. There is evidence that beta-adrenoceptor antagonists are less frequently prescribed in elderly CHF patients, and that this lack of treatment is associated with impaired outcomes. Establishing which beta-adrenoceptor antagonists, if any, are effective in elderly CHF is therefore of extreme importance. The elderly have a reduced cardiovascular reserve and may be less tolerant of the introduction of a vasoconstricting beta-adrenoceptor antagonist. In addition, the higher proportion of elderly CHF patients with relatively preserved systolic function (for which no treatment has been proven to reduce mortality and morbidity) means that we cannot say with certainty that beta-adrenoceptor antagonists have been proven to be effective in a general elderly CHF population. Third-generation beta-adrenoceptor antagonists with vasodilating actions in addition to their beta-adrenoceptor antagonist effects may offer several theoretical advantages over earlier beta-adrenoceptor antagonists for elderly CHF patients. Three of this class (carvedilol, bucindolol and nebivolol) have been evaluated with respect to their efficacy in reducing mortality and morbidity in CHF, and only two of these (carvedilol and nebivolol) had a proven outcome benefit in a properly powered randomised, controlled trial. Only the Study of the Effects of Nebivolol Intervention on Outcomes and Rehospitalisation in Seniors with Heart Failure (which used the vasodilating third-generation beta-adrenoceptor antagonist nebivolol) has prospectively investigated the treatment of CHF in elderly patients, including those with preserved systolic function, and demonstrated a significant reduction in the risk of death or cardiovascular hospitalisation. In conclusion, prescribers are advised that nebivolol should be preferred in elderly patients with CHF, because of its proven efficacy in a representative group of elderly CHF patients.

[Effect of nitrogen oxide donor and inhibitor on some biochemical indices of the brain of intact rats and rats with subarachnoidal hemorrages]

An effect of nitrogen oxide donator Nebilet and inhibitor of NO-synthase L-Name in concentration 10(-4) and 10(-5) on some biochemical indices in vitro has been studied. It was established that an incubation of tissues with nitrogen oxide donator results in an increase of nitrits' level, some intensification of LPO and activation of antioxidant defense enzymes, especially in rats with SAH. On the contrary, an incubation of cerebral homogenate with inhibitor of NO-synthase L-NAME resulted in considerable lowering of nitrits' level, significant activation of LPO.

[Special features of pathogenesis and pharmacotherapy of chronic heart failure in women]

At present in Europe number of deaths due to diseases of cardiovascular system in women has exceeded number of deaths in men. It has been established that process of cardiac remodeling proceeds differently in women and men. This determines different prognosis of the course of chronic heart failure. So after acute myocardial infarction in women more often develops chronic heart failure with preserved systolic left ventricular function while in men prevails chronic heart failure with systolic dysfunction. Substantial differences exist in efficacy of pharmacotherapy: for instance thrombolysis in women is less effective than in men, women are less sensitive to angiotensin converting enzyme inhibitors, administration of digoxin, some antiarrhythmic drugs cause complications in women more often than in men.

Nebivovol and carvedilol induce NO-dependent coronary vasodilatation that is unlikely to be mediated by extracellular ATP in the isolated guinea pig heart

In contrast to classical beta-adrenoreceptor antagonists, nebivolol and carvedilol possess endothelium-dependent vasorelaxant properties. It has been proposed that nebivolol and carvedilol activate microvascular endothelium into producing NO by the release of extracellular ATP and subsequent stimulation of endothelial P(2) receptors. Here we tested this hypothesis in the coronary circulation of the isolated guinea pig heart. We analyzed the role of NO in the coronary vasodilatation induced by nebivolol and carvedilol as well as a possible involvement of extracellular ATP in these responses. Nebivolol and carvedilol (3-30 x 10(-6) M) induced a concentration-dependent coronary vasodilatation that was inhibited by NO-synthase inhibitor, L-NAME (10(-4) M). In contrast to nebivolol and carvedilol, neither atenolol nor labetalol acted as a coronary vasodilator. Vasodilatation induced by nebivolol and carvedilol was affected neither by the P(1) receptor antagonist, 8-sulfophenyl theophylline (8-SPT, 10(-5) M), nor by the P(2) receptor antagonist, suramin (10(-5) M). On the other hand, ATP-induced coronary vasodilatation (0.3-10 x 10(-6) M) was strongly inhibited by L-NAME (10(-4) M), partially inhibited by 8-SPT (10(-5) M), while suramin (10(-5) M) had a minor effect. In conclusion, in the isolated guinea pig heart nebivolol and carvedilol, but not their classical counterparts (atenolol, labelatol), act as NO-dependent coronary vasodilators. It seems unlikely that this response is mediated by the release of extracellular ATP.

Effects of nebivolol versus carvedilol on left ventricular function in patients with chronic heart failure and reduced left ventricular systolic function

BACKGROUND

Beta-adrenoceptor antagonist (beta-blocker) therapy results in a significant improvement in left ventricular (LV) systolic function and prognosis in patients with chronic heart failure. Both carvedilol and nebivolol produce hemodynamic and clinical benefits in chronic heart failure, but it is unknown whether their peculiar pharmacologic properties produce different effects on LV function.

OBJECTIVE

To assess the effects on LV function of nebivolol compared with carvedilol in patients with chronic heart failure and reduced LV systolic function.

METHODS

Seventy patients with a LV ejection fraction <or=40% and in New York Heart Association (NYHA) functional class II or III were randomly assigned to receive carvedilol or nebivolol therapy for 6 months. At baseline and after 6 months of treatment, all patients were assessed clinically and by biochemical and hematological investigation, ECG, 24-hour Holter monitoring, echocardiogram, measurement of ventilatory function, and a 6-minute walk test.

RESULTS

Compared with baseline values LV end-systolic volume decreased and LV ejection fraction increased in both the carvedilol (from 79 +/- 38mL to 73 +/- 43mL and from 33% +/- 6% to 37% +/- 11%) and the nebivolol group (from 72 +/- 35mL to 66 +/- 32mL and from 34% +/- 7% to 38% +/- 10%), although the between-group differences were not statistically significant. ECG data showed a decrease in resting HR in both groups (from 83 +/- 20 bpm to 66 +/- 11 bpm for carvedilol and from 81 +/- 15 bpm to 65 +/- 11 bpm for nebivolol; p < 0.001 vs baseline for both groups) but no difference in the PQ, QRS, and QT intervals. Hematologic (in particular, N-terminal pro-brain natriuretic peptide), Holter monitoring (with the exception of HR), and respiratory functional data did not show any significant variation in either group after 6 months' therapy. SBP and DBP decreased in both groups. A small reduction in mean NYHA functional class from baseline was seen in both groups (from 2.5 +/- 0.5 to 2.2 +/- 0.5 for carvedilol [p < 0.05] and from 2.3 +/- 0.4 to 2.2 +/- 0.5 for nebivolol [not significant]). The 6-minute walk test showed a trend toward an increase in the walking distance in both groups. During 6 months of treatment no significant differences in adverse events were observed between the groups.

CONCLUSION

Nebivolol is as effective as carvedilol in patients with symptomatic chronic heart failure and reduced LV systolic function.

[Cardioselective beta-adrenoblockers in patients with stable angina pectoris. Comparison of efficacy and safety]

AIM

To compare efficacy and safety of cardioselectivc beta-blockers (BB) in patients with stable angina.

MATERIAL AND METHODS

An open comparative randomized trial with participation of 40 patients suffering from stable angina (NYHA FC II-III) was made. All the patients were divided into two groups. Patients of group 1 received betaxolol, those of group 2--other selective BB: metoprolol (n = 13), bisoprolol N = 6, nebivolol (n = 1). The BB dose was doubled each 2 weeks up to achievement of the maximal tolerable dose. The trial continued for 2 months during which the patients were also given aspirin, statins, ACE inhibitors, mononitrates, amlodipin and thiazide diuretics. The efficacy of the treatment was assessed by the data of the treadmill test by Brus protocol, echocardiography according to ASE recommendations, high resolution ultrasound examination of endothelium-related relaxation of the brachial artery. Lipid transport parameters were estimated with enzyme techniques.

RESULTS

A mean dose of betaxolol, metoprolol and bisoprolol was 14 +/- 4.5 mg/day, 127 +/- 24 mg/ day, 10 +/- 4 mg/day. A noticeable lowering of heart rate (HR) and blood pressure (BP) was observed in both groups, but HR in group 1 decreased more (57.35 +/- 5.19 and 62.4 +/- 8.84 b/m, respectively, p = 0.033) and systolic pressure showed a trend to greater reduction. Exercise tolerance in both groups was compatible. The lowest threshold HR was achieved in betaxolol group (a fall from 133.8 +/- 23.5) to 105.0 +/- 14, 23 b/min (p+0.027). Endotheium-related relaxation of the brachial artery was improved in betaxolol group: the diameter of the artery increased from 6.38 +/- 4.32 to 9.22 +/- 4.37% (p = 0.057), the peak blood flow velocity--from 14.81 +/- 3.91 to 23.87 +/- 3.7% (p = 0.031). In group 2 a positive trend in these parameters was not observed. BB had no negative effect on left ventricular contractility, parameters of transmitral blood flow, bronchial conduction, metabolism.

CONCLUSION

Compared to other BB, betaxolol had a stronger effect on hemodynamic parameters (HR and BP) at rest and exercise, improved endothelial vascular function in patients with stable angina.

[Nebivolol effects on the cardiovascular system and the kidneys in pregnant and puerperal women with hypertension]

AIM

To study nebivolol efficacy in pregnant and puerperal women with hypertension.

MATERIAL AND METHODS

Monitoring of endothelial function, central and peripheral hemodynamics (HD), myocardial function, intrarenal circulation and microalbuminuria (MAU) was performed in 90 pregnant (67 hypertensive and 23 normotensive) and 18 puerperal women who were diagnosed to have hypertension in pregnancy. The above parameters were estimated in 23 hypertensive gravidas and 18 puerperas treated with nebivolol.

RESULTS

Hypertensive gravidas had marked endothelial dysfunction (ED), impaired intrarenal HD, MAU, high total peripheral vascular resistance and left ventricular myocardial mass index (LVMMI). The puerperas with hypertension had ED, MAU, frequently HD disorders and a trend to a LVMMI rise. Nebivolol effectively reduced blood pressure, had a nephroprotective action, and improved HD and endothelial function.

CONCLUSION

Nebivolol (a highly selective beta 1-adrenoblocker) administration is effective pathogenetic treatment of pregnant and puerperal women with hypertension and may improve short- and long-term prognoses of such patients.

[Estimation of the protective effect of Nebilet for perioperative cardiac complications in patients underwent vascular surgery: results of prospective study]

We report results of our prospective study - administration of Nebilet in 30 patients in perioperative period. Aim of this study is to estimate the protective effect of Nebilet for perioperative cardiac complications (nonfatal myocardial infarction and cardiac death) in patients which underwent recostructive vascular surgery. Patients were administrated Nebilet (2.5 to 7.5 mg/per day, according to arterial pressure and heart rates) 20 days before operation and 2 months after surgery. In early postoperative period we performed the control examinations: troponin T (1, 3, 7 days), ECG (1 day), echocardiography (1-2 day) and 2 months after operation (ECG and echocardiography). During whole follow up period we controlled in patients arterial pressure and heart rates.

Nebivolol reduces nitroxidative stress and restores nitric oxide bioavailability in endothelium of black Americans

BACKGROUND

Alterations in endothelial function may contribute to increased susceptibility of black Americans to cardiovascular disease. The ability to pharmacologically reverse endothelial dysfunction in blacks was tested with nebivolol, a beta1-selective agent with vasodilating and antioxidant properties.

METHODS AND RESULTS

The effects of nebivolol on endothelial nitric oxide (NO), superoxide (O2-), and peroxynitrite concentration (ONOO-) release were studied in human umbilical vein endothelial cells and iliac artery endothelial cells isolated from age-matched black and white donors. Kinetics and concentrations of NO/O2-/ONOO- were measured simultaneously with nanosensors from single cells and shown to have significant interracial differences. The rate of NO release was &5 times slower in blacks than in whites (94 versus 505 nmol . L(-1).s(-1)), whereas the rates of release were faster by &2 times for O2- and &4 times for ONOO- (22.1 versus 9.4 nmol.L(-1).s(-1) for O2- and 810 versus 209 nmol.L(-1).s(-1) for ONOO-). Pretreatment with 1.0 to 5.0 micromol/L nebivolol restored NO bioavailability in endothelial cells from black donors with concurrent reductions in O2- and ONOO- release, similar to levels in the endothelium of whites. The effects of nebivolol were dose-dependent and not observed with atenolol; similar effects were observed with apocynin, an NAD(P)H oxidase inhibitor.

CONCLUSIONS

Reduced endothelial NO bioavailability in American blacks is mainly due to excessive O2- and ONOO- generation by NAD(P)H and uncoupled endothelial NO synthase. Nebivolol decreased O2- and ONOO- concentrations and restored NO bioavailability in blacks to the level recorded in cells from whites, independently of beta1-selective blockade.

The role of the new beta-blockers in treating cardiovascular disease

The beta-adrenergic receptor blockers play an important role in the management of cardiovascular disease, including hypertension and chronic heart failure. However, concerns regarding safety and tolerability with currently available agents can limit their use. The beta-blockers vary with regard to several pharmacologic properties, including beta1/beta2 selectivity, intrinsic sympathomimetic activity, and, with the newest beta-blockers, vasodilation. These pharmacologic differences may result in clinically important differences in tolerability and hemodynamic properties. Nebivolol is a novel beta-blocker with both a greater degree of selectivity for beta1-adrenergic receptors than other agents in this class and an ability to stimulate endothelial nitric oxide production, leading to vasodilation and other potential clinical effects. Published randomized, controlled, multicenter studies with nebivolol have shown that once-daily treatment significantly reduces systolic and diastolic blood pressure in patients with mild-to-moderate hypertension, compared with placebo, in a dose-dependent manner, and is well tolerated, with an adverse event profile similar to that of placebo. When compared with other beta-blockers as well as with other antihypertensive classes of agents in head-to-head trials, nebivolol demonstrated similar antihypertensive efficacy and a lower incidence of adverse events. Nebivolol has also been shown to significantly reduce morbidity and mortality in a large population of elderly patients with chronic heart failure, independent of left ventricular ejection fraction. Nebivolol is currently available in Europe for the management of hypertension and is expected to be available soon in the United States.