Nebivolol and its 4-keto derivative increase nitric oxide in endothelial cells by reducing its oxidative inactivation

Beta-blockers for Atherosclerosis Prevention: a Missed Opportunity?

PURPOSE OF REVIEW

Current guidelines for the management of arterial hypertension endorse β-adrenergic receptor blocking agents (beta-blockers, BBs) as being particularly useful for hypertension in specific situations such as symptomatic angina, tachycardia, post-myocardial infarction, heart failure with reduced ejection fraction (HFrEF), and as an alternative to angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) in hypertensive women planning pregnancy or at least of child-bearing potential. One of the most common uses of BBs is in patients with a recent myocardial infarction, with or without hypertension. Although this one use is specifically in a setting of atherosclerotic cardiovascular disease (ASCVD), it is not primarily for atheroprevention, but rather for cases with impaired systolic function, and it is intended primarily to lessen adverse cardiac remodeling and worsening of congestive heart failure (CHF). The BB class consists of numerous agents which differ widely in pharmacologic properties and physiologic effects. These differences include selectivity for β-adrenergic receptors and their subtypes, hydro- or lipophilicity, effects on blood pressure and heart rate, influence on lipoprotein and glucose metabolism, and direct impact on the artery wall, including platelet reactivity, endothelial function, infiltration of inflammatory cells and on inflammation per se, and on smooth muscle cell proliferation. Importantly, BBs are not commonly used for prevention of atherosclerosis or ASCVD per se. Many studies of early-generation BBs showed adverse effects on lipoprotein levels and metabolism of glucose and insulin and thus discouraged their use in atheroprevention. Nevertheless, newer BBs often have neutral or favorable metabolic effects on these important factors in ASCVD pathophysiology, and recent scientific studies now document direct beneficial effects of BBs on the artery wall. This document reviews both types of newer data, not only to encourage consideration of BB treatment to reduce ASCVD in the present, but also to call for future research to better explore the clinical settings in which BBs may be proven to have additional benefit in preventing ASCVD when added to the better-established treatments for dyslipidemia and diabetes.

RECENT FINDINGS

Relatively recent publications have clarified the diversity among BBs regarding adverse, neutral, or favorable effects on lipoproteins (especially triglycerides (TG) and low-density lipoprotein (LDL)) and on glucose/insulin metabolism. Specifically, the newer BBs (metoprolol ER, carvedilol ER, bisoprolol, and nebivolol) are now documented to be metabolically beneficial. These new data are complex but instructive regarding potential mechanisms of the diverse effects of various BBs on metabolism. Further and more importantly, these new data refute the traditional, but now outmoded, concept that BBs are universally harmful metabolically and therefore must be used sparingly, if at all, for atheroprevention. Recent studies have also reported exciting new data regarding how certain BBs can reduce platelet adhesion and improve the function of the major cell types in the artery wall, including the endothelium, macrophages, and smooth muscle cells. Specifically, BBs can improve endothelial function by enhancing arterial vasodilation and by reducing monocyte adhesion and transmigration. Further, BBs can decrease numbers and activity of inflammatory cells, including decreasing proliferation of smooth muscle cells and their transformation into inflammatory cells. These data help with the crucial step of distinguishing among available BBs regarding their likely overall arterial effects, whether to accelerate or prevent the development of atherosclerosis. In this regard, there is even some limited published information beyond these intermediary steps, going directly to the clinically more important endpoints of atherosclerosis and ASCVD events. The negative metabolic effects observed with the use of traditional/earlier generations of BBs have discouraged use of any BBs to prevent ASCVD. These adverse effects are not seen, however, with newer BBs. Thus, BBs continue to be a useful component of combination regimens not only in the treatment of arterial hypertension, heart failure, and arrhythmia, but also potentially in the prevention of atherosclerosis and ASCVD. Despite this exciting potential, further research is greatly needed to better establish the possible benefits of the most promising BBs as they might work in combination with other better-established atheropreventive agents. Specifically, there is a need for randomized, prospective, cardiovascular outcome trials (CVOTs) in high-risk patients, adding a BB to background LDL-lowering (statins, etc.), TG-lowering (specifically icosapent ethyl, which reduces ASCVD in patients with high TG, although apparently not via TG-lowering), and/or anti-diabetic (sodium glucose transport-2 inhibitors, SGLT2i, and glucagon-like protein-1 receptor agonists, GLP1-RA) treatments, as indicated in a given subject population.

Identification of the New Metabolite of Nebivolol Using Liquid Chromatography Coupled with High-Resolution Mass Spectrometry and Chemometrics

In this study, the phase I hepatic metabolism pathway of a cardiovascular drug nebivolol was proposed on the basis of a human liver microsomes assay with the use of LC-HR-MS coupled with the chemometric method. Six biotransformation products were found with the assistance of chemometric analysis. Five of them were identified as the previously reported products of alicyclic hydroxylation and dihydroxylation, aromatic hydroxylation, as well as alicyclic oxidation of the parent compound. Moreover, one metabolite, not reported so far, was found to be a product of N-dealkylation of nebivolol-2-amino-1-(6-fluoro-3,4-dihydro-2H-1-benzopyran-2-yl)ethan-1-ol. The novel metabolite was submitted to an in silico toxicity analysis to assess its biological properties. The applied computational methods indicated a significantly elevated risk of its mutagenic activity, compared to the parent molecule. Several metabolites of the nebivolol described in the literature were not detected in this study, indicating their non-hepatic origin.

Abnormal Blood Coagulation and Kidney Damage in Aged Hamsters Infected with Severe Acute Respiratory Syndrome Coronavirus 2

Systemic symptoms have often been observed in patients with coronavirus disease 2019 (COVID-19) in addition to pneumonia, however, the details are still unclear due to the lack of an appropriate animal model. In this study, we investigated and compared blood coagulation abnormalities and tissue damage between male Syrian hamsters of 9 (young) and over 36 (aged) weeks old after intranasal infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Despite similar levels of viral replication and inflammatory responses in the lungs of both age groups, aged but not young hamsters showed significant prolongation of prothrombin time and prominent acute kidney damage. Moreover, aged hamsters demonstrated increased intravascular coagulation time-dependently in the lungs, suggesting that consumption of coagulation factors causes prothrombin time prolongation. Furthermore, proximal urinary tract damage and mesangial matrix expansion were observed in the kidneys of the aged hamsters at early and later disease stages, respectively. Given that the severity and mortality of COVID-19 are higher in elderly human patients, the effect of aging on pathogenesis needs to be understood and should be considered for the selection of animal models. We, thus, propose that the aged hamster is a good small animal model for COVID-19 research.

Critical role of oxidized LDL receptor-1 in intravascular thrombosis in a severe influenza mouse model

Although coagulation abnormalities, including microvascular thrombosis, are thought to contribute to tissue injury and single- or multiple-organ dysfunction in severe influenza, the detailed mechanisms have yet been clarified. This study evaluated influenza-associated abnormal blood coagulation utilizing a severe influenza mouse model. After infecting C57BL/6 male mice with intranasal applications of 500 plaque-forming units of influenza virus A/Puerto Rico/8/34 (H1N1; PR8), an elevated serum level of prothrombin fragment 1 + 2, an indicator for activated thrombin generation, was observed. Also, an increased gene expression of oxidized low-density lipoprotein (LDL) receptor-1 (Olr1), a key molecule in endothelial dysfunction in the progression of atherosclerosis, was detected in the aorta of infected mice. Body weight decrease, serum levels of cytokines and chemokines, viral load, and inflammation in the lungs of infected animals were similar between wild-type and Olr1 knockout (KO) mice. In contrast, the elevation of prothrombin fragment 1 + 2 levels in the sera and intravascular thrombosis in the lungs by PR8 virus infection were not induced in KO mice. Collectively, the results indicated that OLR1 is a critical host factor in intravascular thrombosis as a pathogeny of severe influenza. Thus, OLR1 is a promising novel therapeutic target for thrombosis during severe influenza.

Molecules and Mechanisms to Overcome Oxidative Stress Inducing Cardiovascular Disease in Cancer Patients

Reactive oxygen species (ROS) are molecules involved in signal transduction pathways with both beneficial and detrimental effects on human cells. ROS are generated by many cellular processes including mitochondrial respiration, metabolism and enzymatic activities. In physiological conditions, ROS levels are well-balanced by antioxidative detoxification systems. In contrast, in pathological conditions such as cardiovascular, neurological and cancer diseases, ROS production exceeds the antioxidative detoxification capacity of cells, leading to cellular damages and death. In this review, we will first describe the biology and mechanisms of ROS mediated oxidative stress in cardiovascular disease. Second, we will review the role of oxidative stress mediated by oncological treatments in inducing cardiovascular disease. Lastly, we will discuss the strategies that potentially counteract the oxidative stress in order to fight the onset and progression of cardiovascular disease, including that induced by oncological treatments.

Renal protective effect of nebivolol in rat models of acute renal injury: role of sodium glucose co-transporter 2

BACKGROUND

Upregulation of the sodium glucose co-transporter (SGLT2) is implicated in acute renal injury (ARI) progression and is regulated by extracellular signal-regulated kinase (ERK), hypoxia-inducible factor 1 alpha (HIF1α) or prostaglandin E2 (PGE2). This study aimed to assess the possible protective effect of nebivolol on renal ischemia/reperfusion (IR) and glycerol-induced ARI targeting SGLT2 via modulating the ERK-HIF1α pathway.

METHODS

Rats were divided into control, sham, IR or nebivolol-treated group, in which rats were treated with nebivolol (10 mg/kg) for 3 days prior to the induction of IR. The rats were subjected to renal ischemia by bilateral clamping of the pedicles for 45 min, followed by 24 h reperfusion. Another group of rats received the vehicle or nebivolol (10 mg/kg) for 3 days followed by injection of 50% glycerol (8 ml/kg, IM) or saline. Kidney function tests, systolic blood pressure (SBP), oxidative stress markers [malondialdehyde (MDA) and NADPH oxidase] and kidney levels of nitric oxide (NO), inducible nitric oxide synthase (iNOS), HIF1α, ERK phosphorylation and PGE2 were determined. Additionally, renal sections were used for histological grading of renal injury and immunological expression of SGLT2.

RESULTS

ARI rats showed significantly increased SBP, poor kidney function tests, increased oxidative stress, iNOS, NO, HIF1α levels, decreased PGE2 and ERK phosphorylation and upregulation of SGLT2 expression. Nebivolol treatment protected against the kidney damage both on the biochemical and histological levels.

CONCLUSION

Nebivolol has a direct renoprotective effect, at least in part, by down-regulating SGLT2 possibly via modulating HIF1α, ERK activity and PGE2 production.

Metoprolol and Nebivolol Prevent the Decline of the Redox Status of Low-Molecular-Weight Aminothiols in Blood Plasma of Rats During Acute Cerebral Ischemia

Cerebral ischemia has previously been shown to cause a systemic decrease in levels of the reduced forms of low-molecular-weight aminothiols [cysteine (Cys), homocysteine (Hcy), and glutathione (GSH)] in blood plasma. In this study, we examined the effect of beta-adrenergic receptor (β-AR) antagonists metoprolol (Met) and nebivolol (Neb) on the redox status of these aminothiols during acute cerebral ischemia in rats. We used a model of global cerebral ischemia (bilateral occlusion of common carotid arteries with hypotension lasting for 10 minutes). The antagonists were injected 1 hour before surgery. Total and reduced Cys, Hcy, and GSH levels were measured 40 minutes after the start of reperfusion. Neb (0.4 and 4 mg/kg) and Met (8 and 40 mg/kg) treatment increased the levels of reduced aminothiols and the global methylation index in the hippocampus. The treatments also prevented any decrease in reduced aminothiol levels in blood plasma during ischemia. Although both of these drugs eliminated delayed postischemic hypoperfusion, only Neb reduced neuronal damage in the hippocampus. The results indicate an essential role of β1-AR blockage in the maintenance of redox homeostasis of aminothiols in the plasma and brain during acute cerebral ischemia.

Protective Effects of the Third Generation Vasodilatory Βeta - Blocker Nebivolol against D-Galactosamine - Induced Hepatorenal Syndrome in Rats

BACKGROUND:

Renal dysfunction is very common in patients with advanced liver cirrhosis and portal hypertension. The development of renal failure in the absence of clinical, anatomical or pathological causes renal of failure is termed hepatorenal syndrome (HRS).

AIM:

The present study was constructed to investigate the possible protective effects of nebivolol (Nebi) against D-galactosamine (Gal)-induced HRS in rats.

MATERIAL AND METHODS:

Rats were treated with Nebi for ten successive days. On the 8th day of the experiment, they received a single dose of Gal. Serum levels of Cr, BUN, Na+ and K+ as well as AST, ALT, total bilirubin (TB), NH3 and endothelin-1 (ET-1) were determined following Gal administration. Moreover, renal and liver contents of MDA, GSH, F2-isoprostanes (F2-IPs), tumor necrosis factor-alpha (TNF-α), nuclear factor kappa-B (NF-κB), total nitric oxide (NO), in addition to activities of caspase-3 (Cas-3), heme oxygenase-1 (HO-1), inducible and endothelial NO synthase (iNOS and eNOS) enzymes were also assessed. Finally, histopathological examination was performed.

RESULTS:

Nebi attenuated Gal-induced renal and hepatic dysfunction. It also decreased the Gal-induced oxidative stress and inflammatory recruitment.

CONCLUSION:

Results demonstrated both nephroprotective and hepatoprotective effects of Nebi against HRS and suggested a role of its antioxidant, anti-inflammatory, anti-apoptotic and NO-releasing properties.

Protective effects of Nebivolol against interleukin-1β (IL-1β)-induced type II collagen destruction mediated by matrix metalloproteinase-13 (MMP-13)

The pathological progression of osteoarthritis (OA) involves degradation of articular cartilage matrix. Type II collagen is the main component of cartilage matrix, which is degraded by pro-inflammatory cytokines such as IL-1β mediated by MMP-13. Nebivolol, a licensed drug used for the treatment of hypertension in clinics, displays its anti-inflammatory capacity in various conditions. However, whether Nebivolol has a protective effect on cartilage matrix degradation has not been reported before. In this study, we investigated the effects of Nebivolol on regulating the expression of MMP-13 and degradation of type II collagen. Our results indicate that Nebivolol alleviated the increase in gene expression, protein expression, and activity of MMP-13 induced by IL-1β. Importantly, IL-1β strikingly reduced the levels of type II collagen in cell culture supernatants, which was reversed by treatment with Nebivolol in a dose-dependent manner. Mechanistically, Nebivolol was found to alleviate the increased levels of phosphorylated IκBα and reduced levels of total IκBα induced by IL-1β, which subsequently mitigated p65 nuclear translocation and the transcriptional activity of NF-κB. Furthermore, our results indicated that IL-1β treatment resulted in a significant increase in expression of the transcriptional factor interferon regulatory factor-1 (IRF-1) at both the mRNA and protein levels, which was significantly ameliorated by treatment with Nebivolol. The combination of these findings suggests that Nebivolol can potentially be applied in human OA treatment.

Physiology and pathophysiology of oxLDL uptake by vascular wall cells in atherosclerosis

Atherosclerosis is a progressive disease in which endothelial cell dysfunction, macrophage foam cell formation, and smooth muscle cell migration and proliferation, lead to the loss of vascular homeostasis. Oxidized low-density lipoprotein (oxLDL) may play a pre-eminent function in atherosclerotic lesion formation, even if their role is still debated. Several types of scavenger receptors (SRs) such as SR-AI/II, SRBI, CD36, lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), toll-like receptors (TLRs) and others can promote the internalization of oxLDL. They are expressed on the surface of vascular wall cells (endothelial cells, macrophages and smooth muscle cells) and they mediate the cellular effects of oxLDL. The key influence of both oxLDL and SRs on the atherogenic process has been established in atherosclerosis-prone animals, in which antioxidant treatment and/or silencing of SRs has been shown to reduce atherogenesis. Despite some discrepancies, the indication from cohort studies that there is an association between oxLDL and cardiovascular (CV) events seems to point toward a role for oxLDL in atherosclerotic plaque progress and disruption. Finally, randomized clinical trials using antioxidants have demonstrated benefits only in high-risk patients, suggesting that additional proofs are still needed to better define the involvement of each type of modified LDL in the development of atherosclerosis.

Nitric Oxide Contributes to Vasomotor Tone in Hypertensive African Americans Treated With Nebivolol and Metoprolol

Endothelial dysfunction is more prevalent in African Americans (AAs) compared with whites. The authors hypothesized that nebivolol, a selective β1 -antagonist that stimulates nitric oxide (NO), will improve endothelial function in AAs with hypertension when compared with metoprolol. In a double-blind, randomized, crossover study, 19 AA hypertensive patients were randomized to a 12-week treatment period with either nebivolol 10 mg or metoprolol succinate 100 mg daily. Forearm blood flow (FBF) was measured using plethysmography at rest and after intra-arterial infusion of acetylcholine and sodium nitroprusside to estimate endothelium-dependent and independent vasodilation, respectively. Physiologic vasodilation was assessed during hand-grip exercise. Measurements were repeated after NO blockade with L-N(G) -monomethylarginine (L-NMMA) and after inhibition of endothelium-derived hyperpolarizing factor (EDHF) with tetraethylammonium chloride (TEA). NO blockade with L-NMMA produced a trend toward greater vasoconstriction during nebivolol compared with metoprolol treatment (21% vs 12% reduction in FBF, P=.06, respectively). This difference was more significant after combined administration of L-NMMA and TEA (P<.001). Similarly, there was a contribution of NO to exercise-induced vasodilation during nebivolol but not during metoprolol treatment. There were significantly greater contributions of NO and EDHF to resting vasodilator tone and of NO to exercise-induced vasodilation with nebivolol compared with metoprolol in AAs with hypertension.

Effect of nebivolol on liver regeneration in an experimental 70% partial hepatectomy model

BACKGROUND

Factors affecting liver regeneration are still relevant. The purpose of this study is to investigate the effect of nebivolol treatment on liver regeneration in rats in which 70% partial hepatectomy was performed.

METHODS

Three groups were created: the control group, the low dose group, and the high dose group, with 20 rats in each group and 70% hepatectomy was performed in all rats. Immediately after partial liver resection, 2 mL physiological saline solution was administered to the control group via oral gavage, 0.5 mg/kg nebivolol was administered via oral gavage to the low dose group and 2 mg/kg nebivolol was administered via oral gavage to the high dose group. On the 1^st and 5^th days after liver resection, 10 subjects were sacrificed from each group, and liver weights and the mitotic count and Ki-67 were measured.

RESULTS

Regenerating liver weight on the 1^st and 5^th days after partial hepatectomy was statistically different in the low dose and high dose nebivolol groups compared to the control group. Mitotic count on the 1^st day after partial hepatectomy was significantly higher in the low dose and high dose nebivolol groups than the control group. There was no statistically significant difference detected between the three groups for the 5^th day. On the 1^st day, Ki-67 rates were significantly higher in both groups given nebivolol than the control group. However, 5^th day results were not statistically significant.

CONCLUSION

Nebivolol increases regeneration after partial hepatectomy in rats.

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.

Activated human mast cells induce LOX-1-specific scavenger receptor expression in human monocyte-derived macrophages

Objective

Activated mast cells in atherosclerotic lesions degranulate and release bioactive compounds capable of regulating atherogenesis. Here we examined the ability of activated human primary mast cells to regulate the expression of the major scavenger receptors in cultured human primary monocyte-derived macrophages (HMDMs).

Results

Components released by immunologically activated human primary mast cells induced a transient expression of lectin-like oxidized LDL receptor (LOX-1) mRNA in HMDMs, while the expression of two other scavenger receptors, MSR1 and CD36, remained unaffected. The LOX-1-inducing secretory components were identified as histamine, tumor necrosis factor alpha (TNF-α), and transforming growth factor beta (TGF-β1), which exhibited a synergistic effect on LOX-1 mRNA expression. Histamine induced a transient expression of LOX-1 protein. Mast cell –induced increase in LOX-1 expression was not associated with increased uptake of oxidized LDL by the macrophages.

Conclusions

Mast cell-derived histamine, TNF-α, and TGF-β1 act in concert to induce a transient increase in LOX-1 expression in human primary monocyte-derived macrophages. The LOX-1-inducing activity potentially endows mast cells a hitherto unrecognized role in the regulation of innate immune reactions in atherogenesis.

Endothelial dysfunction in conduit arteries and in microcirculation. Novel therapeutic approaches

The vascular endothelium not only is a single monolayer of cells between the vessel lumen and the intimal wall, but also plays an important role by controlling vascular function and structure mainly via the production of nitric oxide (NO). The so called "cardiovascular risk factors" are associated with endothelial dysfunction, that reduces NO bioavailability, increases oxidative stress, and promotes inflammation contributing therefore to the development of atherosclerosis. The significant role of endothelial dysfunction in the development of atherosclerosis emphasizes the need for efficient therapeutic interventions. During the last years statins, angiotensin-converting enzyme inhibitors, angiotensin-receptor antagonists, antioxidants, beta-blockers and insulin sensitizers have been evaluated for their ability to restore endothelial function (Briasoulis et al., 2012). As there is not a straightforward relationship between therapeutic interventions and improvement of endothelial function but rather a complicated interrelationship between multiple cellular and sub-cellular targets, research has been focused on the understanding of the underlying mechanisms. Moreover, the development of novel diagnostic invasive and non-invasive methods has allowed the early detection of endothelial dysfunction expanding the role of therapeutic interventions and our knowledge. In the current review we present the available data concerning the contribution of endothelial dysfunction to atherogenesis and review the methods that assess endothelial function with a view to understand the multiple targets of therapeutic interventions. Finally we focus on the classic and novel therapeutic approaches aiming to improve endothelial dysfunction and the underlying mechanisms.

Comparative effects of nebivolol and metoprolol on red cell distribution width and neutrophil/lymphocyte ratio in patients with newly diagnosed essential hypertension

High level of circulating red cell distribution width (RDW) and neutrophil/lymphocyte (N/L) ratio may reflect ongoing vascular inflammation and play an important role in pathophysiology of hypertension. We evaluate the effects of nebivolol and metoprolol on the RDW and N/L in new essential hypertensive patients. After baseline assessment, 72 patients were randomly allocated to 5 mg/d of nebivolol (n = 37, 20 men) or 100 mg/d of metoprolol (n = 35, 18 men) and treated for 6 months. Blood pressure (BP), heart rate (HR), RDW, and N/L were measured before and after treatment. BP significantly decreased with both drugs (P < 0.001). Analog reduction was observed for resting HRs (P < 0.001), but metoprolol caused greater HR fall as compared with nebivolol (P < 0.001). After 6 months of treatment, nebivolol significantly lowered not only RDW but also the total white blood cell and N/L (P < 0.001, P = 0.023, P = 0.017, respectively). No changes were observed in metoprolol group. Percent decrease in RDW was found to be significantly higher in nebivolol than in the metoprolol group (P = 0.001) and remained also after correction for confounders (P = 0.012). Nebivolol improved RDW and N/L to a greater extent than metoprolol in patients with hypertension. These favorable effects may participate, together with the BP reduction, at the favorable properties of the drug in hypertension.

Targeting NOS as a therapeutic approach for heart failure

Nitric oxide is a key signaling molecule in the heart and is produced endogenously by three isoforms of nitric oxide synthase, neuronal NOS (NOS1), endothelial NOS (NOS3), and inducible NOS (NOS2). Nitric oxide signals via cGMP-dependent or independent pathways to modulate downstream proteins via specific post translational modifications (i.e. cGMP-dependent protein kinase phosphorylation, S-nitrosylation, etc.). Dysfunction of NOS (i.e. altered expression, location, coupling, activity, etc.) exists in various cardiac disease conditions, such as heart failure, contributing to the contractile dysfunction, adverse remodeling, and hypertrophy. This review will focus on the signaling pathways of each NOS isoform during health and disease, and discuss current and potential therapeutic approaches targeting nitric oxide signaling to treat heart disease.

Effect of IL-10 on LOX-1 expression, signalling and functional activity: an atheroprotective response

The lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) has gained attention for its pro-inflammatory potential in atherogenesis. This study evaluates LOX-1 receptor modulation in the presence of an atheroprotective cytokine, interleukin-10 (IL-10). Both oxidized low-density lipoprotein (oxLDL) and IL-10 stimulated LOX-1 cell surface expression on THP-1 macrophages. However, our study demonstrates differential roles of oxLDL and IL-10 on LOX-1 functionality. Seemingly, oxLDL-induced LOX-1 promoted pro-inflammatory signalling by increasing intracellular NO, a substrate for pro-inflammatory peroxynitrite. In contrast, IL-10-induced LOX-1 facilitated scavenging of extracellular oxLDL without any effect on pro-inflammatory signalling. The atheroprotective effects of IL-10 were demonstrated by both facilitation of cellular oxLDL uptake and expression of LOXIN, an atheroprotective haplotype of the LOX-1 gene. Thus, increased expression of IL-10 may help to attenuate the risk of atherosclerosis developed by pro-inflammatory signal(s) generated through the interaction of oxLDL with its cognate receptor LOX-1 on macrophages.

Protective effect of nebivolol on reserpine-induced neurobehavioral and biochemical alterations in rats

Reserpine-induced orofacial dyskinesia is a model that shares some mechanists' aspects with tardive dyskinesia whose pathophysiology has been related to oxidative stress. The present study was aimed to explore neuroprotective effects of nebivolol, an antihypertensive agent, on reserpine-induced neurobehavioral and biochemical alterations in rats. Reserpine (1mg/kg, s.c.) was used to induce neurotoxicity. Administration of reserpine for 3 days every other day significantly increased the vacuous chewing movements (VCMs), tongue protrusions (TPs) and reduced the locomotor activity in rats. Pre-treatment with nebivolol (5 and 10mg/kg, p.o. for 5 days) showed dose dependant decrease in VCMs and TP induced by reserpine. Nebivolol also showed significant improvement in locomotor activity. Reserpine significantly increased lipid peroxidation and reduced the levels of defensive antioxidant enzymes like catalase (CAT), superoxide dismutase (SOD) and reduced glutathione (GSH) in rat brain. Nebivolol reversed these effects of reserpine on oxidative stress indices; indicating amelioration of oxidative stress in rat brains. The results of the present study indicated that nebivolol has a protective role against reserpine-induced orofacial dyskinesia. Thus, the use of nebivolol as a therapeutic agent for the treatment of tardive dyskinesia may be considered.

Nitric oxide synthases in heart failure

SIGNIFICANCE

The regulation of myocardial function by constitutive nitric oxide synthases (NOS) is important for the maintenance of myocardial Ca(2+) homeostasis, relaxation and distensibility, and protection from arrhythmia and abnormal stress stimuli. However, sustained insults such as diabetes, hypertension, hemodynamic overload, and atrial fibrillation lead to dysfunctional NOS activity with superoxide produced instead of NO and worse pathophysiology.

RECENT ADVANCES

Major strides in understanding the role of normal and abnormal constitutive NOS in the heart have revealed molecular targets by which NO modulates myocyte function and morphology, the role and nature of post-translational modifications of NOS, and factors controlling nitroso-redox balance. Localized and differential signaling from NOS1 (neuronal) versus NOS3 (endothelial) isoforms are being identified, as are methods to restore NOS function in heart disease.

CRITICAL ISSUES

Abnormal NOS signaling plays a key role in many cardiac disorders, while targeted modulation may potentially reverse this pathogenic source of oxidative stress.

FUTURE DIRECTIONS

Improvements in the clinical translation of potent modulators of NOS function/dysfunction may ultimately provide a powerful new treatment for many hearts diseases that are fueled by nitroso-redox imbalance.

Nebivolol and metoprolol: long-term effects on inflammation and oxidative stress in essential hypertension

Arterial hypertension is characterised by increased oxidative stress and inflammation, which are associated with further cardiovascular risk. The aim of our study was to investigate the long-term effects of nebivolol and metoprolol succinate on oxidative stress, and on inflammatory and pro-inflammatory markers in patients with hypertension. Eighty patients with never-treated mild-to-moderate essential hypertension, aged 30-65 years, were randomised to a 5 mg daily dose of nebivolol or a 50-100 mg daily dose of metoprolol succinate. Brachial blood pressure, plasma oxidized LDL (oxLDL), interleukin-6 (IL-6), high-sensitivity C-reactive protein (hsCRP), fibrinogen, intercellular adhesion molecule-1 (ICAM-1), asymmetric dimethylarginine (ADMA), and urine 8-isoprostane levels were measured before and after 1 year of treatment. Nebivolol and metoprolol reduced equally significantly brachial blood pressure. The oxLDL was significantly reduced in both groups (p < 0.01 and for both drugs), but only nebivolol reduced 8-isoprostanes (p = 0.01). In the metoprolol group, change in oxLDL levels correlated with change in systolic blood pressure (r = 0.45; p < 0.01) and pulse pressure (r = 0.47; p < 0.01). Both metoprolol and nebivolol reduced ICAM-1 (p < 0.01). There was no change in IL-6, hsCRP, fibrinogen, or ADMA levels in either group. These data suggest that in long-term antihypertensive treatment both the cardioselective beta blocker metoprolol succinate and the vasodilating beta blocker nebivolol have inflammation-related effects but only nebivolol has a favourable blood pressure-independent effect on oxidative stress.

Nebivolol: an endothelium-friendly selective β1-adrenoceptor blocker

Nebivolol is a highly selective β1-adrenoceptor blocker, which also stimulates endothelial nitric oxide synthase and scavenges reactive oxygen species (ROS). These characteristics endow nebivolol, compared with conventional β-blockers, with a favorable hemodynamic profile for the treatment of hypertension, chronic heart failure, and possibly other cardiovascular diseases. Nebivolol is a racemic mixture of d- and l-isomers. Its β1-antagonistic properties reside primarily with d-nebivolol although both isomers are capable of increasing the release of NO from the endothelium after binding to β2- or β3-adrenergic receptors. The latter action results in vasodilatation and reduced vascular resistance. Nebivolol also scavenges ROS in a receptor-independent manner by direct interaction with free radicals. By scavenging ROS nebivolol not only reduces oxidant stress but also augments NO bioavailability. The endothelial nitric oxide synthase -stimulating and ROS scavenging effects of nebivolol act synergistically to provide cardiovascular protection in addition to its β1-antagonistic action.

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.

The anti-oxidant and anti-apoptotic effects of nebivolol and zofenopril in a model of cerebral ischemia/reperfusion in rats

The aim of this experiment was to investigate whether nebivolol and zofenopril have protective effects against oxidative damage and apoptosis induced by cerebral ischemia/reperfusion (I/R). There were seven groups of rats, with each containing eight rats. The groups were: the control group, I/R group, I/R plus zofenopril, I/R plus nebivolol, I/R plus nebivolol and zofenopril, zofenopril only and nebivolol only. Cerebral I/R was induced by clamping the bilateral common carotid artery and through hypotension. The rats were sacrificed 1h after ischemia, and histopathological and biochemical analyses were carried out on their brains. The total antioxidant capacity was evaluated by using an automated and colorimetric measurement method developed by Erel. I/R produced a significant increase in the levels of total oxidant status and malondialdehyde levels, the number of caspase-3 immunopositive cells and activities of prolidase and paraoxonase in brain when compared with the control group (p<0.05). A significant decrease in brain total antioxidant capacity and nitric oxide levels were found in I/R group when compared with the control group (p<0.05). Both nebivolol and zofenopril treatment prevented decreasing of the total antioxidant capacity and nitric oxide levels, produced by I/R in the brain (p<0.05). Both nebivolol and zofenopril treatment prevented the total oxidant status, malondialdehyde levels, activities of paraoxonase and prolidase from increasing in brains of rats exposed to I/R (p<0.05). In conclusion, both nebivolol and zofenopril protected rats from ischemia-induced brain injury. The protection may be due to the indirect prevention of oxidative stress and apoptosis.

β-blockade with nebivolol for prevention of acute ischaemic events in elderly patients with heart failure

Aim. This subanalysis of the Study of the Effects of Nebivolol Intervention on Outcomes and Hospitalisation in Seniors with Heart Failure (SENIORS) investigates whether treatment with nebivolol, a β-blocker with nitric oxide-releasing properties, can provide additional benefits besides its effects on heart failure (HF), by reducing cardiac ischaemic events in patients with HF of ischaemic aetiology. Material and methods. A double-blind, randomised, placebo-controlled, multicentre trial of nebivolol in 2128 elderly patients. For this analysis, data were extracted for 2128 elderly (≥70 years) HF patients in whom coronary artery disease (CAD) was the underlying aetiology (68,2 %; 717 placebo-treated patients and 735 assigned to nebivolol). The main endpoint was the composite of cardiac ischaemic events at 2 year follow-up: death/hospitalisation for myocardial infarction, unstable angina or sudden death, as originally identified in the case report form. Results. At follow-up, nebivolol treatment was associated with a one-third reduction in the risk of ischaemic events, the composite endpoint occurring in 15,9 % of placebo and 10,7 % of nebivolol-treated patients (HR 0,68; 95 % CI 0,51 to 0,90; p=0,008). This effect was independent of age, gender and ejection fraction. No difference in this composite endpoint was observed in the subgroup of patients of non-ischaemic aetiology. Conclusion. Nebivolol was effective in reducing cardiac ischaemic events in patients with HF of ischaemic aetiology. The prevention of ischaemic events can be an additional beneficial effect of β-blockade in HF patients with underlying CAD.

A comparative study of nebivolol and (S) atenolol on blood pressure and heart rate on essential hypertensive patients

Objectives:

To study the effect of nebivolol 5 mg once daily versus (S)-atenolol 25 mg once daily in patients with essential hypertension.

Materials and Methods:

A prospective study was conducted at RLJH and Research Centre which included 30 patients in each group with essential hypertension. The sex, age, presenting illness, and family history of the patients were recorded. Investigations such as blood sugar, urine analysis, kidney function test, lipid profile, and ECG were performed before starting the treatment. Any adverse effects during the treatment were noted. Blood pressure and heart rate were recorded at baseline and during follow-up. One group received nebivolol 5 mg once daily and other group (S)atenolol 25 mg once daily. Patients were followed-up every 15 days for 3 months.

Results:

Nebivolol group had 18 males and 12 females with mean age 50.6 ± 9.5 years, (S)-atenolol had 16 males and 14 females with mean age 54.4 ± 9 years. Patients receiving nebivolol and (S)-atenolol showed a significant fall (P <·0001) in systolic (SBP), diastolic blood pressure (DBP), and heart rate at the end of first, second, and third month when compared to baseline. The difference in fall in SBP and DBP was insignificant between the groups, but fall in heart rate was significant (P <·0001). Adverse effects such as headache, dizziness, and fatigue were reported with both drugs.

Conclusion:

Reduction of blood pressure with nebivolol and (S)atenolol was similar, but fall in blood pressure from baseline was highly significant in both groups.

Nebivolol in chronic heart failure: current evidence and future perspectives

IMPORTANCE OF THE FIELD

Chronic activation of the sympathetic nervous system leads to deterioration of cardiovascular function in heart failure patients. In systolic heart failure, beta-blockers were proven to be effective in decreasing the number of deaths and improving morbidity. However, beta-blockers are a heterogeneous drug group, consisting of agents with different selectivity for adrenergic receptors and/or additional effects in heart or peripheral circulation.

AREAS COVERED IN THE REVIEW

We describe the role of the sympathetic nervous system, beta-blockers and specifically nebivolol in chronic heart failure.

WHAT THE READER WILL GAIN

Nebivolol is a third-generation beta-blocker, with high beta(1)/beta(2) selectivity. Moreover, it has important vasodilating properties, by stimulating the production of nitric oxide. Smaller studies have already shown beneficial effects of nebivolol treatment on surrogate end points in heart failure patients. The recently published SENIORS (Phase III) study in an elderly heart failure population demonstrated a decreased number of clinical events in patients treated with nebivolol. Importantly, this effect was observed in patients with both impaired and preserved left ventricular systolic function.

TAKE HOME MESSAGE

Specific beta-blockers may have distinct effects in various subgroups of heart failure patients. So far, nebivolol is the only beta-blocker to have been shown effective in elderly heart failure patients, regardless of their left ventricular ejection fraction.

[Advantages of vasodilating beta-blockers in congestive heart failure]

Beta-blockers play a pivotal role in the treatment of chronic systolic heart failure. However, the pharmacological family of beta-blockers is inhomogeneous regarding their pharmacological properties and their clinical effects can differ substantially according to different pharmacological properties. Because of vasodilator effects, the third generation of beta-blockers has additional potential across the cardiovascular diseases, from hypertension to heart failure. Nebivololol has both high selectivity for beta1-adrenergic receptors, no intrinsic sympathetic activity and ability to stimulate endothelial nitric oxide production. Such properties result in specific hemodynamic effects compared with others beta-blockers. Such properties also result in both high tolerability and positive metabolic effects which are crucial in high-risk groups. In the SENIORS trial, nebivolol demonstrated its efficacy and high tolerability in elderly patients with chronic heart failure irrespective of the left ventricular ejection fraction. More clinical trials would be useful to exhibit specific benefits of nebivolol in other high-risk groups of patients.

Nebivolol: the somewhat-different beta-adrenergic receptor blocker

Although its clinical use in Europe dates almost 10 years, nebivolol is a beta-blocker that has been only recently introduced in the U.S. market. Like carvedilol, nebivolol belongs to the third generation of beta-blockers, which possess direct vasodilator properties in addition to their adrenergic blocking characteristics. Nebivolol has the highest beta(1)-receptor affinity among beta-blockers and, most interestingly, it substantially improves endothelial dysfunction via its strong stimulatory effects on the activity of the endothelial nitric oxide synthase and via its antioxidative properties. Because impaired endothelial activity is attributed a major causal role in the pathophysiology of hypertension, coronary artery disease, and congestive heart failure, the endothelium-agonistic properties of nebivolol suggest that this drug might provide additional benefit beyond beta-receptor blockade. Although lesser beta-blocker-related side effects have been reported in patients with chronic obstructive pulmonary disease or impotence taking nebivolol, side effects and contraindications overlap those of other beta-blockers. Clinically, this compound has been proven to have antihypertensive and anti-ischemic effects as well as beneficial effects on hemodynamics and prognosis in patients with chronic congestive heart failure. Further studies are now necessary to compare the benefit of nebivolol with that of other drugs in the same class and, most importantly, its prognostic impact in patients with hypertension.

Radical scavenging and NO-releasing properties of selected β-adrenoreceptor antagonists

It is claimed that novel beta-adrenolytic drugs possess superior antioxidant properties as compared to classical selective or non-selective beta-adrenoceptor antagonists. Here we tested this notion by analyzing radical scavenging properties of selected beta-adrenolytic drugs and their ability to release nitric oxide in biological preparations. Selective beta1-adrenolytics such as nebivolol, atenolol, metoprolol and non-selective beta-adrenolytics with alpha1-receptor blocking properties such as carvedilol and labetalol were chosen for analysis. NO-releasing properties of nebivolol and carvedilol distinguished third generation beta-adrenolytics from their older counterparts while the reactivity towards hydroxyl and peroxyl radicals discerns only carvedilol but not nebivolol. Thus, superior clinical efficacy of third generation beta-adrenolytics may be related to their ability to release NO rather then to their direct antioxidant properties.

Arterial stiffness, hypertension, and rational use of nebivolol

Arterial stiffness plays a key role in the pathophysiology of the cardiovascular system. Some indices of arterial stiffness (pulse wave velocity, augmentation index, characteristics of central blood pressure waveform) may be presently calculated and evaluated in the clinical setting. Age and blood pressure are the two major clinical determinants of increased arterial stiffness, while molecular determinants of arterial stiffness are related to fibrotic components of the extracellular matrix, mainly elastin, collagen and fibronectin. Increased arterial stiffness has been consistently observed in conditions such as hypertension, dyslipidemia and diabetes. Arterial stiffness evaluated by means of carotid-femoral pulse wave velocity yielded prognostic significance beyond and above traditional risk factors. A more favorable effect of calcium channel blockers, diuretics and ACE inhibitors compared with β-blockers on indices of arterial stiffness was observed in several studies. It is conceivable that newer β-blockers with additional vasodilating properties, such as nebivolol, which has favorable effects on carbohydrate and lipid metabolism, as well as on endothelial function and on oxidative stress, may have favorable effects on arterial stiffness, compared with atenolol. In fact, in recent studies, nebivolol was demonstrated to improve artery stiffness to a greater extent than older β-blockers. Because endothelial dysfunction and increased arterial stiffness play an important role in the early atherosclerotic processes and are associated with poor outcomes and increased mortality, independently of blood pressure, the ability of nebivolol to enhance release of endothelium-derived nitric oxide, and consequently improve endothelial function and arterial stiffness, may have significant clinical implications for the use of this agent in the treatment of hypertension and cardiovascular diseases.

Nitric oxide mechanisms of nebivolol

β-blockers are among the most widely used drugs in the prevention and treatment of cardiovascular disease, although they are associated with increased peripheral resistance. Third-generation β-blockers avoid this adverse effect by inducing vasodilation through different mechanisms. In particular, nebivolol, a highly selective blocker of β1-adrenergic receptors, is the only β-blocker known to induce vascular production of nitric oxide, the main endothelial vasodilator. The specific mechanism of nebivolol is particularly relevant in hypertension, where nitric oxide dysfunction occurs. Indeed, nebivolol is able to reverse endothelial dysfunction. Nebivolol induces nitric oxide production via activation of β3-adrenergic receptors, which can explain the good metabolic profile observed after treatment with this drug. Moreover, nebivolol can also stimulate the β3-adrenergic receptor-mediated production of nitric oxide in the heart, and this stimulation can result in a greater protection against heart failure. In conclusion, nebivolol has a unique profile among antihypertensive drugs, adding to a very high selectivity against β1 adrenergic receptors, and an agonist action on β3 receptors and nitric oxide (NO), which has led to clinically significant improvements in hypertensive patients.

Proteomic profiling during atherosclerosis progression: Effect of nebivolol treatment

There is a great need for the identification of biomarkers for the early diagnosis of atherosclerosis and the agents to prevent its progression. The aim of this study was to explore the effect of 24 week of nebivolol (a third-generation vasodilatory beta-blocker) treatment on serum protein profiles in Apo E(-/-) mice during atherosclerosis progression. Nebivolol treated and non-treated (the control group) groups consisted of 10 genetically modified homozygous Apo E(-/-) mice. Proteomic analyses were performed using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) in the serum samples from the nebivolol treated and non-treated Apo E(-/-) mice. The protein profiles obtained using three different chips, CM10 (weak cation-exchange), H50 (reverse phase), and IMAC30-Cu(2+) (immobilized metal affinity capture) were statistically analyzed using the ProteinChip data manager 3.0 program. At the end of 24 week of nebivolol-treatment period, a total of 662 protein/peptide clustering peaks were detected using 12 different conditions and reading with high and low intensity laser energy. The highest total number of protein/peptide clusters was found on H50 chip array. The peak intensities of 95 of the 662 protein/peptide clusters were significantly different in the nebivolol-treated atherosclerotic group in comparison to the non-treated control mice groups (P < 0.05). Forty-three protein/peptides were up-regulated (high signal intensity) while 52 protein/peptides had lower signal intensity (down-regulated) in the nebivolol-treated atherosclerotic group. The proteomic profiles of nebivolol-treated Apo E(-/-) mice were different than the control group indicating a potential role of nebivolol in atherosclerosis. Our study contributes to understand the efficacy of nebivolol on serum protein/peptide profiles during atherosclerosis development.

Investigation of the different adrenoceptor targets of nebivolol enantiomers in rat thoracic aorta

BACKGROUND AND PURPOSE

Nebivolol is a highly selective beta(1)-adrenoceptor antagonist with beta(3)-adrenoceptor agonist properties and is a racemate mixture of D- and L-enantiomers. However, the cellular mechanisms of the effects of each enantiomer are not yet clear and are a matter for debate. The aim of the present experiments was to determine the adrenoceptors involved in the vascular effects of D- and L-enantiomers of nebivolol in rat thoracic aorta.

EXPERIMENTAL APPROACH

Responses to nebivolol enantiomers were evaluated in rings of thoracic aorta from male Sprague-Dawley rats.

KEY RESULTS

D-nebivolol (0.1-10 micromol.L(-1)), but not L-nebivolol, significantly shifted to the right the concentration-response curve to phenylephrine, an alpha(1)-adrenoceptor agonist, in a concentration-dependent manner. For the following experiments, aortic rings were constricted with endothelin 1 and now both enantiomers produced an endothelium-dependent relaxation of the rings involving the nitric oxide pathway. This relaxation was not modified by 1 micromol.L(-1) CGP 20,712A (beta(1)-adrenoceptor antagonist), but significantly blunted by 7 micromol.L(-1) L-74,8337 (beta(3)-adrenoceptor antagonist). However, only the vasorelaxation induced by D-nebivolol was significantly reduced by 1 micromol.L(-1) ICI 118,551 (beta(2)-adrenoceptor antagonist).

CONCLUSIONS AND IMPLICATIONS

Our results suggest that the nebivolol enantiomers act on different targets. D-nebivolol induced vasorelaxation by activating beta(2)- and beta(3)-adrenoceptors and antagonizing alpha(1)-adrenoceptors. L-nebivolol induced vasorelaxation by activating only beta(3)-adrenoceptors in our model. Our results emphasize that nebivolol is a beta(1)-adrenoceptor antagonist with several important pharmacological differences from other beta(1)-adrenoceptor antagonists.

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.

Nebivolol treatment reduces serum levels of asymmetric dimethylarginine and improves endothelial dysfunction in essential hypertensive patients

BACKGROUND

This study was conducted to evaluate (i) the effect of nebivolol, a selective beta1-adrenergic receptor antagonist, on plasma concentration of asymmetric dimethylarginine (ADMA) and on flow-mediated dilation (FMD) in essential hypertensive patients; (ii) the effect of serum derived from the treated hypertensive patients on ADMA and on dimethylarginine dimethylaminohydrolase 2 (DDAH2), the enzyme that selectively degrades ADMA, in human umbilical vein endothelial cells (HUVECs).

METHODS

Forty healthy subjects and 40 matched essential hypertensive patients treated with atenolol and nebivolol according to a double-blind, randomized design participated in the study. Evaluation of brachial artery (BA) reactivity was performed by a longitudinal B-mode scan of the right BA. ADMA and L-arginine were measured by high-performance liquid chromatography. DDAH2 expression and endothelial nitric oxide synthase activity (eNOS) were also evaluated in HUVECs.

RESULTS

ADMA levels were significantly decreased and FMD increased only in patients receiving nebivolol (P < 0.01). Furthermore, in nebivolol group, we found a significant correlation between changes in ADMA levels and changes in FMD (P < 0.01). Sera derived from patients treated with nebivolol but not with atenolol decreased ADMA and increased DDAH2 expression and eNOS activity (P < 0.001) in HUVECs.

CONCLUSIONS

The results of this study demonstrate that the improvement of endothelial dysfunction induced by nebivolol in hypertensive patients may be related to its effect on circulating ADMA levels. Although the mechanism by which nebivolol reduces circulating ADMA in hypertensive patients remains unclear, our ex vivo results suggest that the upregulation of DDAH2 expression may have a role.

Effects of nebivolol on endothelial gene expression during oxidative stress in human umbilical vein endothelial cells

The endothelium plays a key role in the development of atherogenesis and its inflammatory and proliferative status influences the progression of atherosclerosis. The aim of this study is to compare the effects of two beta blockers such as nebivolol and atenolol on gene expression in human umbilical vein endothelial cells (HUVECs) following an oxidant stimulus. HUVECs were incubated with nebivolol or atenolol (10 micromol/L) for 24 hours and oxidative stress was induced by the addition of oxidized (ox)-LDL. Ox-LDL upregulated adhesion molecules (ICAM-1, ICAM-2, ICAM-3, E-selectin, and P-selectin); proteins linked to inflammation (IL-6 and TNFalpha), thrombotic state (tissue factor, PAI-1 and uPA), hypertension such as endothelin-1 (ET-1), and vascular remodeling such as metalloproteinases (MMP-2, MMP-9) and protease inhibitor (TIMP-1). The exposure of HUVECs to nebivolol, but not to atenolol, reduced these genes upregulated by oxidative stress both in terms of protein and RNA expression. The known antioxidant properties of the third generation beta blocker nebivolol seem to account to the observed differences seen when compared to atenolol and support the specific potential protective role of this beta blocker on the expression of a number of genes involved in the initiation and progression of atherosclerosis.

Major differences in gene expression in human coronary smooth muscle cells after nebivolol or metoprolol treatment

OBJECTIVE

Vascular smooth muscle cells play a pivotal role in all stages of atherogenesis. Targeting their inflammatory and proliferative qualities might therefore inhibit the progression of atherosclerosis. This study aimed to characterize and compare the effects of the beta-receptor antagonists nebivolol and metoprolol on gene expression in human coronary artery smooth muscle cells (hcaSMC).

METHODS AND RESULTS

hcaSMC were incubated with nebivolol or metoprolol (10(-5) mol/l) for 72 h. The downregulated genes are involved in inflammatory processes, oxidative stress and smooth muscle cell proliferation: i.e. downregulated were by nebivolol: interleukin-1alpha, cyclooxygenase-2, tumor-necrosis-factor (TNF)-alpha-induced protein 6, PDGF-A, growth-related oncogenes 2 and 3. Metoprolol increased the expression of interleukin-1alpha, cyclooxygenase-1, TNF-alpha-induced protein 3, heme oxygenase 1 and granulocyte/macrophage-colony-stimulating factor. In addition downregulated was monocyte chemoattractant protein 1 (MCP-1) mRNA by nebivolol. Nebivolol (10(-5) mol/l) reduced the amount of basal NF-kappaB after 48 and 52 h but not metoprolol. In the culture supernatants, MCP-1 concentrations were reduced by nebivolol.

CONCLUSIONS

Nebivolol induced changes in the expression of inflammatory mediators in hcaSMC. These results add to data that suggest specific anti-inflammatory qualities of a beta-blocker of the third generation in comparison to metoprolol.

Vasodilator Effects of Nebivolol in a Rat Model of Hypertension and a Rabbit Model of Congestive Heart Failure

Both hypertension and congestive heart failure are characterized by a reduced vasodilatory capacity. In both conditions, the impairment of endothelial function is mainly the result of a reduced nitric oxide availability. The highly beta1-selective third-generation adrenoceptor blocker nebivolol displays additional endothelium-dependent vasodilating actions in humans as well as in animal models. In this study, we investigated whether these vasodilating properties of nebivolol are preserved in conditions with endothelial dysfunction. The vasodilatory effects of nebivolol were compared with those of the muscarinic agonist methacholine in isolated aortic rings obtained from spontaneous hypertensive rats and rabbits with experimental heart failure. The methacholine-induced responses were attenuated in aortic rings from both spontaneous hypertensive rats and congestive heart failture rabbits (42+/-6% and 25+/-3% vs. 89+/-3% and 54+/-7% for controls, respectively; P<0.05, n=6-13), indicating an endothelial dysfunction in these preparations. In contrast, nebivolol-induced vasorelaxation remained unaffected in both preparations when compared to control preparations (40+/-12% and 43+/-6% vs. 52+/-8% and 50+/-13% for controls, respectively; P>0.05, n=6-13). These results implicate that the favorable hemodynamic profile of nebivolol may be preserved in patients with hypertension or congestive heart failure despite an impaired endothelial function.

Effect of dl-nebivolol, its enantiomers and metabolites on the intracellular production of superoxide and nitric oxide in human endothelial cells

Nebivolol, a third generation selective beta(1)-adrenoceptor (beta(1)-AR) antagonist, has been reported to reduce intracellular oxidative stress and to induce the release of nitric oxide (NO) from the endothelium. Nebivolol is also subjected to a complex metabolic process where glucuronidation, aromatic and alicyclic hydroxylation are the major pathways leading to several metabolites. We have studied the effect of nebivolol, its enantiomers and metabolites on intracellular oxidative stress and NO availability in human umbilical vein endothelial cells (HUVECs). Furthermore, since the receptors involved in this endothelial effect of nebivolol remain controversial, we have studied this matter by the use of antagonists of beta-AR. dl-Nebivolol, d-nebivolol and l-nebivolol significantly reduced the formation of reactive oxygen species (ROS) and superoxide induced by oxidized-low density lipoprotein (ox-LDL), although the racemic and l-form were significantly more active than d-nebivolol in this activity. A marked decrease in the availability of intracellular NO was found in HUVECs exposed to ox-LDL and this parameter was normalized by the prior incubation with dl-nebivolol, d-nebivolol and l-nebivolol; the effect of racemate was mainly mimicked by its l-enantiomer. eNOS activity significantly increased by a 5-min contact of HUVECs with dl-nebivolol and l-nebivolol, but not with d-nebivolol, and a similar pattern was observed when the intracellular calcium increase was measured. The metabolites A2, A3', A12 and A14 but not A1, A3 and R 81,928, derived from different metabolic pathways, retained the antioxidant activity of the parent racemic compound dl-nebivolol, reducing the intracellular formation of ROS and superoxide. The effects of dl-nebivolol on intracellular formation of NO, eNOS activity and intracellular Ca(2+) were partially antagonized by the antagonists of beta(1-2)-AR nadolol or by the beta(3)-AR antagonist SR59230A and further antagonized by their combination or by (beta(1-2-3)-AR antagonist bupranolol. In conclusion, this study shows that the NO releasing effect of nebivolol is mainly due to its l-enantiomer; the racemate and its enantiomers possess a remarkable antioxidant activity that contributes to its effect on the cellular NO metabolism and the activation of beta(3)-AR through a calcium dependent pathway is involved in the mechanisms leading to the NO release.