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.     

Antihypertensive therapy with celiprolol: a new cardioselective beta blocker

Celiprolol is a new generation beta blocker with a novel profile of activity that includes a high degree of cardioselectivity, partial beta 2-agonist activity, and possibly a degree of direct peripheral vasodilation. The drug is hydrophilic, with fewer cardiodepressant effects than other beta antagonists. These ancillary properties may make celiprolol a more suitable beta blocker for use in a broader range of hypertensive patients than conventional agents, and additional work is ongoing in patients with obstructive airways disease, peripheral vascular disorders and those with impaired cardiac function to substantiate and extend current findings.     

Nebivolol: new therapy update

Nebivolol is a beta-blocker under U.S. Food and Drug Administration review for the treatment of hypertension. The unique pharmacologic properties of nebivolol include high specificity for the beta-1 receptor and a nitric oxide-mediated vasodilatory effect. The agent provides significant blood pressure reduction from baseline values as compared with placebo. Clinical trials have demonstrated that nebivolol reduces blood pressure similarly to atenolol, bisoprolol, amlodipine, nifedipine, lisinopril, and hydrochlorothiazide. The tolerability of nebivolol is similar to or better than that of these agents. In elderly patients (> or = 70 years of age) with clinically stable congestive heart failure, the addition of nebivolol to the treatment regimen improved the time to all-cause mortality and cardiovascular hospital admissions over that of placebo. If approved, nebivolol would likely be a viable alternative therapy for hypertension and heart failure; however, additional studies are needed in patients having coronary artery disease.     

Bopindolol: Czechoslovak experience with a new beta blocker in the treatment of hypertension.

Bopindolol is a nonselective beta blocker with mild intrinsic sympathomimetic activity. One of the drug's main benefits is its prolonged effect, lasting for 24 hours, which makes it possible to administer bopindolol in a single daily dose, a fact that may improve patient adherence to therapy. A double-blind study was performed in two centers, comparing bopindolol with metoprolol in 86 hypertensive patients. Baseline diastolic blood pressure (BP) was 100 to 120 mm Hg. The effects of bopindolol or metoprolol on BP and heart rate were similar: return to normal values was achieved in 70% of patients with either drug. A 6-month study at another center found that bopindolol did not affect the levels of total cholesterol, low-density and high-density lipoprotein cholesterol or triglycerides. Another 12-month study documented a decrease in total cholesterol, apolipoprotein (apo) A1 and apo B. The apo A/B ratio rose, thus improving the atherosclerotic index. No deterioration of glucose tolerance or immunoreactive insulin response to glucose was seen after 6 months of bopindolol administration. Bopindolol satisfactorily modifies not only resting but also exercise BP during isometric and isotonic load, thus reducing BP fluctuation during physical activities of the hypertensive patient. The drug exerts no effect on renal and liver function, electrolyte balance and hematologic parameters. Bopindolol is a very useful drug of first choice in mild and moderate hypertension. Bopindolol's main advantages include its prolonged action, good tolerance and a beneficial effect on risk factors of atherosclerosis (lipid and carbohydrate metabolism).     

Comparison of a chronotherapeutically administered beta blocker vs. a traditionally administered beta blocker in patients with hypertension

Increasing systolic blood pressure and heart rate during the early morning results in increased myocardial oxygen demand. The use of beta blockers during this period may decrease cardiac workload, particularly in beta-blocker sensitive patients. The impact of a new chronotherapeutic beta blocker was assessed in 44 hypertensive patients. Patients were randomized to delayed-release propranolol (INP) dosed at 10 p.m. or to traditionally dosed propranolol (ILA) dosed at 8 a.m. for 4 weeks, following which they were switched to the alternative formulation for 4 weeks. Thirty-four-hour ambulatory blood pressure monitoring and pharmacokinetic measurements were obtained. INP and ILA resulted in significant reductions in mean 24-hour blood pressure (-9.0/-6.9 mm Hg and -10.4/-7.7 mm Hg, respectively). The top 25% of responders to high-dose propranolol (sensitive patients) were compared on each formulation. Mean trough reductions were -8.0/-6.7 mm Hg and -7.6/-5.8 mm Hg, respectively. Mean blood pressure reductions in the beta-blocker sensitive patients (n = 11) between 6 a.m. and noon were -15.2/-11.9 mm Hg on INP and -8.0/-4.6 mm Hg on ILA. Heart rate reduction was -14.1 bpm and double product reduction was -3319 in the INP patients between 6 a.m. and 12 noon compared with -10.5 and -2209 in the ILA patients. This study suggests that INP and ILA are effective once-a-day beta blockers, but the use of delayed-release propanolol results in a greater reduction in double product between 6 a.m. and noon in beta-blocker sensitive patients than does traditionally dosed propranolol.     

Acute beta blocker poisoning

It is reported of acute beta-blocker intoxications in 34 patients (16 with talinolol, 18 with propranolol ingestion). The mean ingestion dose was for talinolol 2.5 g, for propranolol 1.55 g, the mean time of latency up to the appearance of intoxication symptoms 116 min after intake of talinolol, 79 min after intake of propranolol. The picture of intoxication was characterized in the two substances by the antiadrenergic effects, there was no more a cardioselectivity in the high ingestion doses. In talinolol were in the first place dysrhythmias, hypotension and vomiting and nausea, respectively, in propranolol central-nervous symptoms and hypotension. Substance-specific intoxication symptoms are also possible. In mixed intoxications alcohol accelerated the beginning of the effect, sedatives prolonged the latency. Threatening of life is to be expected in ingestion doses over 2 g. In 6 patients the course was lethal after extreme doses of talinolol - according to the present experiences due to the too late beginning of therapy and/or insufficient intensity of therapy. Distinct intoxication symptoms need extremely high applications of antidotes of beta-stimulants, in their inffectiveness glucagon. Furthermore, treatment with cardiac pacemakers and 24-hour control in an intensive care unit proved necessary.     

Hemodynamic interactions of a new beta blocker,celiprolol, with nifedipine in angina pectoris

The hemodynamic consequences of blockade at both beta-adrenoceptors and slow calcium channels is of therapeutic importance for patients with angina pectoris. The hemodynamic interaction of a new cardioselective beta blocker, celiprolol, and nifedipine was examined in an acute hemodynamic study using three prospectively matched groups with angiographically confirmed coronary artery disease (n = 10/group). Patients were randomly allocated to intravenous celiprolol (8 mg), sublingual nifedipine (20 mg), or their combination. Rest and exercise (supine bicycle) hemodynamics were determined before and following each therapy. At rest, celiprolol did not alter pumping function; nifedipine reduced diastolic blood pressure and systemic vascular resistance index (SVRI), with a small increase in heart rate. Combination therapy reduced systemic arterial pressure and SVRI; heart rate and cardiac stroke volume index increased. During exercise celiprolol tended to reduce heart rate and cardiac index; nifedipine reduced exercise SVR and cardiac stroke work indices. Combination therapy reduced all components of blood pressure; cardiac stroke work and SVR indices fell. These hemodynamic data suggest that beta blockade with celiprolol may result in a slight depression of cardiac pumping during exercise; however, such effects are offset by the vasodilating actions of nifedipine (reflex sympathetic action offsetting cardiodepression). Thus the acute hemodynamic effects of this combination were seemingly safe in these patients; the longer term effects during maintained therapy should be further assessed.     

Dermatomyositis and polymyositis: new treatment targets on the horizon

Polymyositis (PM) and dermatomyositis (DM) are rare idiopathic inflammatory myopathies (IIM) with a presumed autoimmune pathogenesis. Typical features are subacute onset, proximal, symmetric muscle weakness, elevated serum creatine kinase, and mononuclear cell infiltrates in the muscle biopsy. Strong support for an autoimmune pathogenesis comes from histopathological findings in biopsies of affected muscles. Furthermore, the association with autoantibodies supports the notion that immune-mediated inflammation is involved. PM and DM may occur in isolation or in connection with a connective tissue disease or cancer. The current treatment for IIM consists of first-line high-dose steroids and various conventional second-line treatments. Improvements in treatment for IIM are hampered by difficulties in the design of trials and the low incidence and prevalence of the disease. Cytokines and chemokines are factors involved in the inflammatory process in IIM, and are candidates for future therapeutic targets. Preliminary data with anti-tumour necrosis factor therapy are not very promising, but results of blockers of the lymphotoxin signalling pathway are to be awaited. Anti-B cell therapy may be a valuable therapeutic option for treatment of refractory IIM. The effects of anti-interferon-alpha in IIM are to be awaited, as are results of other anti-cytokine therapies and anti-chemokine therapy. Outcome measures to be used in clinical trials in II M include at present the core sets of outcome proposed by the International Myositis Assessment Clinical Study Group (IMACS).     

Biomarkers for hepatocellular carcinoma: What's new on the horizon?

Treatment of advanced hepatocellular carcinoma remains unsatisfying and so far only prognostic biomarkers like α-fetoprotein have been established. No clear predictive biomarker is currently available for standard of care therapies, including targeted therapies like sorafenib. Novel therapeutic options like immune checkpoint inhibitors may pose new challenges to identification and validation of such markers. Currently, PD-L1 expression via immunohistochemistry and tumor mutational burden via next-generation sequencing are explored as predictive biomarkers for these novel treatments. Limited tissue availability due to lack of biopsies still restricts the use of tissue based approaches. Novel methods exploring circulating or cell free nucleic acids(DNA, RNA or miRNAcontaining exosomes) could provide a new opportunity to establish predictive biomarkers. Epigenetic profiling and next-generation sequencing approaches from liquid biopsies are under development. Sample size, etiologic and geographical background need to be carefully addressed in such studies to achieve meaningful results that could be translated into clinical practice. Proteomics, metabolomics and molecular imaging are further emerging technologies.