Ivabradine: Current and Future Treatment of Heart Failure

Heart Failure: Recent Advances and Breakthroughs

Heart failure (HF) is a common clinical condition encountered in various healthcare settings with a vast socioeconomic impact. Recent advancements in pharmacotherapy have led to the evolution of novel therapeutic agents with a decrease in hospitalization and mortality rates in HF with reduced left ventricular ejection fraction (HFrEF). Lately, the introduction of artificial intelligence (AI) to construct decision-making models for the early detection of HF has played a vital role in optimizing cardiovascular disease outcomes. In this review, we examine the newer therapies and evidence behind goal-directed medical therapy (GDMT) for managing HF. We also explore the application of AI and machine learning (ML) in HF, including early diagnosis and risk stratification for HFrEF.

Therapeutic Use and Molecular Aspects of Ivabradine in Cardiac Remodeling: A Review

Cardiac remodeling can cause ventricular dysfunction and progress to heart failure, a cardiovascular disease that claims many lives globally. Ivabradine, a funny channel (I_f) inhibitor, is used in patients with chronic heart failure as an adjunct to other heart failure medications. This review aims to gather updated information regarding the therapeutic use and mechanism of action of ivabradine in heart failure. The drug reduces elevated resting heart rate, which is linked to increased morbidity and mortality in patients with heart failure. Its use is associated with improved cardiac function, structure, and quality of life in the patients. Ivabradine exerts several pleiotropic effects, including an antiremodeling property, which are independent of its principal heart-rate-reducing effects. Its suppressive effects on cardiac remodeling have been demonstrated in animal models of cardiac remodeling and heart failure. It reduces myocardial fibrosis, apoptosis, inflammation, and oxidative stress as well as increases autophagy in the animals. It also modulates myocardial calcium homeostasis, neurohumoral systems, and energy metabolism. However, its role in improving heart failure remains unclear. Therefore, elucidating its molecular mechanisms is imperative and would aid in the design of future studies.

New Perspectives in the Treatment of Acute and Chronic Heart Failure with Reduced Ejection Fraction

Acute and chronic heart failure with reduced ejection fraction (HFrEF) is a major public health problem, studies showing a 25% survival rate at 5 years after hospitalization. If left untreated, it is a common and potentially fatal disease. In recent years, the medical and device therapies of patients with HFrEF have significantly improved. The aim of our review is to provide an evidence-based update on new therapeutic strategies in acute and chronic settings, to prevent hospitalization and death in patients with HFrEF. We performed a systematic literature search on PubMed, EMBASE, and the Cochrane Database of Systemic Reviews, and we included a number of 23 randomized controlled trials published in the last 30 years. The benefit of beta-blockers and renin-angiotensin-aldosterone system inhibitors in patients with HFrEF is well known. Recent developments, such as sodium-glucose cotransporter 2 inhibitors, vericiguat, transcatheter mitral valve repair, wireless pulmonary artery pressure monitor and cardiac contractility modulation, have also proven effective in improving prognosis. In addition, other new therapeutic agents showed encouraging results, but they are currently being studied. The implementation of personalized disease management programs that directly target the cause of HFrEF is crucial in order to improve prognosis and quality of life for these patients.

β-blockers in advanced cirrhosis: More friend than enemy

Nonselective beta-adrenergic blocker (NSBB) therapy for the prevention of initial and recurrent gastrointestinal bleeding in cirrhotic patients with gastroesophageal varices has been used for the past four decades. NSBB therapy is considered the cornerstone of treatment for varices, and has become the standard of care. However, a 2010 study from the group that pioneered β-blocker therapy suggested a detrimental effect of NSBBs in decompensated cirrhosis, especially in patients with refractory ascites. Since then, numerous additional studies have incompletely resolved whether NSBBs are deleterious, although more recent evidence weighs against a harmful effect. The possibility of a "therapeutic window" has also been raised. We aimed to review the literature to analyze the pros and cons of using NSBBs in patients with cirrhosis, not only with respect to bleeding or mortality but also to other potential benefits and risks. β-blockers are highly effective in preventing first bleeding and recurrent bleeding. Furthermore, NSBBs improve congestion/ischemia of the gut mucosa, decrease intestinal permeability, and therefore indirectly alleviate systemic inflammation. β-blockers shorten the electrocardiographic prolonged QTc interval and may also decrease the incidence of hepatocellular carcinoma. On the other hand, the possibility of deleterious effects in cirrhosis has not been completely eliminated. NSBBs may be associated with an increased risk of portal vein thrombosis, although this could be correlational artifact. Overall, we conclude that β-blockers in cirrhosis are much more of a friend than enemy.

Pharmacological torpor prolongs rat survival in lethal normobaric hypoxia

Resistance to hypoxia is one of the most prominent features of natural hibernation and is expected to be present in the pharmacological torpor (PT) that simulates hibernation. We studied resistance to lethal hypoxia (3.5% oxygen content) in rats under PT. To initiate PT, we used the previously developed pharmacological composition (PC) which, after a single intravenous injection, can induce a daily decrease in Tb by 7 °C-8 °C at the environmental temperature of 22 °C-23 °C. Half-survival (median) time of rats in lethal hypoxia was found to increase from 5 ± 0.8 min in anesthetized control rats to 150 ± 12 min in rats injected with PC, which is a 30-fold increase. Behavioral tests after PT and hypoxia, including the traveling distance, the number of rearing and grooming episodes, revealed that animal responses are significantly restored within a week. It is assumed that the discovered unprecedented resistance of artificially torpid rats to lethal hypoxia may open up broad prospects for the therapeutic use of PT for preconditioning to various damaging factors, treatment of diseases, and extend the so-called "golden hour" for lifesaving interventions.

Simultaneous Optimization of Oral and Transdermal Nanovesicles for Bioavailability Enhancement of Ivabradine Hydrochloride

PURPOSE

Ivabradine hydrochloride is selective pacemaker current (If) ion channel inhibitor used in case of chronic heart failure (CHF) with superior efficacy and lower side effects than most β-blockers. However, the drug suffers from low bioavailability (≈40%) due to extensive first-pass metabolism. Hence, this work aims to formulate nanovesicular platforms to enhance their bioavailability both orally and transdermally.

MATERIALS AND METHODS

A central composite face-centered design was employed to formulate the nanovesicles, both phosphatidylcholine: drug ratio and percentage of pluronic F68 were used as independent variables. The nine developed formulae were characterized in terms of vesicle size (nm), polydispersity index, zeta potential (mV), entrapment efficiency (%). Decreasing vesicle size, increasing negative value of the zeta potential, and increasing entrapment efficiency were the chosen constraints to optimize the engineered nanovesicles. The candidate formula was subjected to further investigation including lyophilization, loading into carbopol gel, in vitro release, imaging with a transmission electron microscope, histopathological examination, in vitro cytotoxicity study and in vivo pharmacokinetics.

RESULTS

The optimized nanovesicular formula was composed of lipid: drug ratio of 3.91:1 and 100% pluronic as a stabilizer. It has particle size, zeta potential and entrapment efficiency of 337.6 nm, -40.5 mV and 30.5, respectively. It was then lyophilized in the presence of 5% trehalose as a cryoprotectant, dispersed in 0.5% carbopol to develop the transdermal gel. The two different forms of the candidate formula (lyophilized and gel form) displayed sustained drug release in comparison to drug solution. The histopathological and cytotoxicity studies showed that the optimized formula was safe and highly biocompatible. The pharmacokinetics parameters measured declared a higher Cmax and half-life of both formulae in comparison to market product (Procoralan®) with a 2.54- and 1.85-folds increase in bioavailability, respectively.

CONCLUSION

Hence, the developed nanovesicles can be reported as the first nanoplatforms to be used for simultaneous ivabradine delivery by both oral and topical routes with enhanced oral and transdermal drug delivery. The developed nanoplatforms hence can be further used to formulate other drugs that suffer from low bioavailability due to extensive first-pass metabolism.

Ivabradine, the hyperpolarization-activated cyclic nucleotide-gated channel blocker, elicits relaxation of the human corpus cavernosum: a potential option for erectile dysfunction treatment

OBJECTIVE

To evaluate the effect of the I_f channel inhibitor, ivabradine on human corpus cavernosum (HCC) smooth muscle tone.

METHODS

HCC samples were obtained from erectile dysfunction(ED) patients (n = 12) undergoing penile prosthesis surgery. Concentration-response curves for ivabradine were exposed to various inhibitory and stimulatory agents. The relaxant and contractile responses to electrical field stimulation (EFS, 10 Hz and 80 Hz) were examined in the presence or absence of ivabradine (10 μM). HCN3 and HCN4 channel expression and localization were determined by Western blot and immunohistochemical analyses of HCC tissues.

RESULTS

Increasing ivabradine concentrations dependently reduced the maximal contractile responses of isolated HCC strips induced by KCl (59.5 ± 2.5%) and phenylephrine (84.0 ± 9.8%), which was not affected by nitric oxide synthase and soluble guanylyl cyclase inhibitors after phenylephrine-induced contraction. Nifedipine and tetraethylammonium inhibited the maximum relaxation to ivabradine by 75% and 39.3%, respectively. Fasudil and sildenafil increased the relaxation response to ivabradine without altering the maximum response. Pre-incubation with ivabradine significantly increased relaxant responses to EFS (p < 0.01) and reduced the contractile tension evoked by EFS (72.3%) (p < 0.001). Ivabradine incubation did not affect the expression and localization of HCN3 and HCN4 channels in the HCC smooth muscle cells.

CONCLUSIONS

Ivabradine exhibits a relaxant effect on HCC tissues, which is likely to be attributed to the blocking of L-type Ca²⁺ channels and the opening of K⁺ channels, independent of changes in the activation of the nitric oxide/cyclic guanosine monophosphate system. Inhibition of HCN channels localized in cavernosal smooth muscle cells may offer pharmacological benefits for patients with cardiovascular risk factors.

Epidemiology of acutely decompensated systolic heart failure over the 2003-2013 decade in Douala General Hospital, Cameroon

AIMS

Acutely decompensated heart failure (HF) (ADHF) is a common cause of hospitalization and mortality worldwide. This study explores the epidemiology and prognostic factors of ADHF in Cameroonian patients.

METHODS AND RESULTS

This was a retrospective study conducted between January 2003 and December 2013 from the medical files of patients followed at the intensive care and cardiovascular units of Douala General Hospital in Cameroon. Clinical, electrocardiographic, echocardiographic, and biological data were collected from 142 patients (58.5% men; mean age 58 ± 14 years) hospitalized for ADHF with reduced ejection fraction (HFrEF), whose left ventricular ejection fraction was <50%, or alternatively whose shortening fraction was <28%, both assessed by echocardiography. The commonest risk factors associated with HFrEF were hypertension (59.2%), diabetes mellitus (16.2%), tobacco use (14.1%), and dyslipidaemia (7.7%), respectively. The major causes of HF in hospitalized patients were hypertensive heart disease (40%, n = 57); hypertrophic cardiomyopathy (33.8%, n = 48); and ischemic heart disease (21.8%, n = 31). The most frequent comorbid conditions were atrial fibrillation (25.4%, n = 36) and chronic kidney disease (18.3%, n = 26). Major biological abnormalities included increased bilirubinemia >12 mg/L (87.5%, n = 124); hyperuricaemia >70 mg/L (84.9%, n = 121); elevated serum creatinine (65.6%, n = 93); anaemia (59.1%, n = 84); hyperglycaemia on admission >1.8 g/L (42.3%, n = 60); and hyponatraemia <135 mEq/L (26.8%, n = 38). At admission, 33.8% (n = 48) of patients had no pharmacological treatment for HF. The most frequently used therapies upon admission included furosemide (50%, n = 71), angiotensin-converting enzyme inhibitors (ACEIs; 40.1%, n = 57); spironolactone (35.2%, n = 50); digoxin (26%, n = 37); beta-blockers (17.7%, n = 25); angiotensin-receptor blockers (ARBs; 7%, n = 10); and nitrates (7.0%). The overall in-hospital mortality rate was 20.4%. Factors associated with poor prognosis were systolic blood pressure <90 mmHg [odds ratio (OR) 3.88; confidence interval (CI) 1.36-11.05, P = 0.011], left ventricular ejection fraction <20% (OR 7.48; CI 2.84-19.71, P < 0.001), decreased renal function (OR 1.03; CI 1.00-1.05, P = 0.026), dobutamine use for cardiogenic shock (OR 2.74;CI 1.00-7.47, P = 0.049), pleural fluid effusion (OR 3.46; CI 1.07-11.20, P = 0.038), and prothrombin time <50% (OR 3.60; CI 1.11-11.68, P = 0.033). The use of ACEIs/ARBs was associated with reduced in-hospital mortality rate (OR 0.17; CI 0.02-0.81, P = 0.006).

CONCLUSIONS

Hypertensive heart disease, hypertrophic cardiomyopathy, and ischemic heart disease are the commonest causes of HF in this Cameroonian population. ADHF is associated with high in-hospital mortality in Cameroon. Hypotension, severe left ventricular systolic dysfunction, renal function impairment, and dobutamine administration were associated with worst acute HF outcomes. ACEIs/ARBs use was associated with improved survival.

IRX1 hypermethylation promotes heart failure by inhibiting CXCL14 expression

To identify the mechanism and functions of IRX1 in heart failure (HF) and provide evidence for new therapies. Bioinformatic analysis was performed to select target genes in HF cells compared to normal groups. Experimental rats were treated in a controllable manner to explore how IRX1 methylation accounted for this disease in vivo. Cardiac ultrasonic and morphologic examinations were conducted to test the mouse heart and evaluate the degree of cardiac impairment at in the level of organization. GSEA analysis revealed the relative enrichment of functions. Immunofluorescent assays, western blotting and qRT-PCR were used to determine the DNA methylation and expression levels. IRX1 was hypermethylated in heart failure and identified as a target gene by bioinformatic analysis. Transverse aortic constriction (TAC) induced heart failure in rats, while 5-aza-2'-deoxycytidine (5-Aza) alleviated heart failure in rats according to medical cardiac indexes. Western blotting and qRT-PCR revealed that a conspicuous difference in the expression of IRX1 and CXCL14 between HF and normal cardiac cells. As a result of gene methylation, left ventricular hypertrophy and cardiac fibrosis is usually accompanied by heart failure. Moreover, is the results implied that the demethylation of IRX1 improves heart failure in vivo and in vitro. IRX1 methylation induced damaged cardiac function and even heart failure, which has important implications for HF treatment and diagnosis.

Pharmacology of Ivabradine and the Effect on Chronic Heart Failure

Chronic Heart Failure (CHF) is a complex clinical syndrome with a high incidence worldwide. Although various types of pharmacological and device therapies are available for CHF, the prognosis is not ideal, for which, the control of increased Heart Rate (HR) is critical. Recently, a bradycardic agent, ivabradine, is found to reduce HR by inhibiting the funny current (If). The underlying mechanism states that ivabradine can enter the Hyperpolarization-activated Cyclic Nucleotide-gated (HCN) channels and bind to the intracellular side, subsequently inhibiting the If. This phenomenon can prolong the slow spontaneous phase in the diastolic depolarization, and thus, reduce HR. The clinical trials demonstrated the significant effects of the drug on reducing HR and improving the symptoms of CHF with fewer adverse effects. This review primarily introduces the chemical features and pharmacological characteristics of ivabradine and the mechanism of treating CHF. Also, some expected therapeutic effects on different diseases were also concluded. However, ivabradine, as a typical If channel inhibitor, necessitates additional research to verify its pharmacological functions.

Cardiac function evaluation for a novel one-step detoxification product of Aconiti Lateralis Radix Praeparata

Background

Aconiti Lateralis Radix Praeparata has been used as the first cardiac drug over a 1000 years in Asian countries. Although most detoxification products are confirmed to be safe, the effect is not potent as desired. In previous study, we designed a one-step detoxification product by fresh cutting and continuously dried, which preserved more water-soluble alkaloids while eliminating toxicity. It is thus necessary to find more in vivo evidence to support its industrial development.

Methods

Initially, network pharmacology was applied to analyze the related pathways of candidate components acting on heart failure diseases. Then, two heart failure models that were induced by propafenone hydrochloride and nimodipine (v/v, 1:1) and were given doxorubicin were carried out to test the cardiac activity. Moreover, the effect on mitochondrial energy metabolism was further assessed.

Results

Network pharmacology results indicated that Aconiti Lateralis Radix Praeparata treated heart failure through cAMP signaling pathway, calcium signaling pathway, adrenergic signaling in cardiomyocytes and so on. These pathways were highly correlated with myocardial contractility and mitochondrial energy metabolism. Trials on heart failure rats demonstrated that the novel processed-product could produce a stronger positive inotropic action and increase more Na⁺–K⁺–ATPase and Ca²⁺–Mg²⁺–ATPase than Heishunpian. Pathological results also revealed the novel one could better restore the morphology of cardiomyocytes and reduce vacuolar lesions. It also could inspire more energy with a lower concentration.

Conclusions

This study provides scientific evidence for the clinical application of new products. It is of great benefit to innovate the industrial detoxification process of Aconitum.

Electronic supplementary material

The online version of this article (10.1186/s13020-018-0219-4) contains supplementary material, which is available to authorized users.

Ivabradine Reduces Digitalis-induced Ventricular Arrhythmias

The I_(f) channel inhibitor ivabradine is recommended for treatment of heart failure but also affects potassium currents and thereby prolongs ventricular repolarization. The aim of this study was to examine the electrophysiological effects of ivabradine on digitalis-induced ventricular arrhythmias. Thirteen rabbit hearts were isolated and Langendorff-perfused. After obtaining baseline data, the digitalis glycoside ouabain was infused (0.2 μM). Monophasic action potentials and ECG showed a significant abbreviation of QT interval (-34 ms, p < 0.05) and action potential duration (APD₉₀ ; -27 ms, p < 0.05). The shortening of ventricular repolarization was accompanied by a reduction in effective refractory period (ERP; -27 ms, p < 0.05). Thereafter, hearts were additionally treated with ivabradine (5 μM). Of note, this did not exert significant effects on QT interval (-4 ms, p = ns) or APD₉₀ (-15 ms, p = ns) but resulted in an increase in ERP (+17 ms, p < 0.05). This led to a significant increase in post-repolarization refractoriness (PRR, +32 ms, p < 0.01) as compared with sole ouabain treatment. Under baseline conditions, ventricular fibrillation (VF) was inducible by a standardized pacing protocol including programmed stimulation and burst stimulation in four of 13 hearts (31%; 15 episodes). After application of 0.2 μM ouabain, eight of 13 hearts were inducible (62%, 49 episodes). Additional infusion of 5 μM ivabradine led to a significant suppression of VF. Only four episodes could be induced in two of 13 hearts (15%). In this study, ivabradine reduced digitalis-induced ventricular arrhythmias. Ivabradine did not affect ventricular repolarization in the presence of digitalis treatment but demonstrated potent anti-arrhythmic properties based on an increase in both ERP and PRR. The study further characterizes the beneficial electrophysiological profile of ivabradine.

HCN Channel Targets for Novel Antidepressant Treatment

Major depressive disorder (MDD) is a chronic and potentially life threatening illness that carries a staggering global burden. Characterized by depressed mood, MDD is often difficult to diagnose and treat owing to heterogeneity of syndrome and complex etiology. Contemporary antidepressant treatments are based on improved monoamine-based formulations from serendipitous discoveries made > 60 years ago. Novel antidepressant treatments are necessary, as roughly half of patients using available antidepressants do not see long-term remission of depressive symptoms. Current development of treatment options focuses on generating efficacious antidepressants, identifying depression-related neural substrates, and better understanding the pathophysiological mechanisms of depression. Recent insight into the brain's mesocorticolimbic circuitry from animal models of depression underscores the importance of ionic mechanisms in neuronal homeostasis and dysregulation, and substantial evidence highlights a potential role for ion channels in mediating depression-related excitability changes. In particular, hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are essential regulators of neuronal excitability. In this review, we describe seminal research on HCN channels in the prefrontal cortex and hippocampus in stress and depression-related behaviors, and highlight substantial evidence within the ventral tegmental area supporting the development of novel therapeutics targeting HCN channels in MDD. We argue that methods targeting the activity of reward-related brain areas have significant potential as superior treatments for depression.