Binding of levosimendan, a calcium sensitizer, to cardiac troponin C

Renal Congestion in Heart Failure: Insights in Novel Diagnostic Modalities

Heart failure is increasingly prevalent and is estimated to increase its burden in the following years. A well-reported comorbidity of heart failure is renal dysfunction, where predominantly changes in the patient's volume status, tubular necrosis or other mechanical and neurohormonal mechanisms seem to drive this impairment. Currently, there are established biomarkers evaluating the patient's clinical status solely regarding the cardiovascular or renal system. However, as the coexistence of heart and renal failure is common and related to increased mortality and hospitalization for heart failure, it is of major importance to establish novel diagnostic techniques, which could identify patients with or at risk for cardiorenal syndrome and assist in selecting the appropriate management for these patients. Such techniques include biomarkers and imaging. In regards to biomarkers, several peptides and miRNAs indicative of renal or tubular dysfunction seem to properly identify patients with cardiorenal syndrome early on in the course of the disease, while changes in their serum levels can also be helpful in identifying response to diuretic treatment. Current and novel imaging techniques can also identify heart failure patients with early renal insufficiency and assess the volume status and the effect of treatment of each patient. Furthermore, by assessing the renal morphology, these techniques could also help identify those at risk of kidney impairment. This review aims to present all relevant clinical and trial data available in order to provide an up-to-date summary of the modalities available to properly assess cardiorenal syndrome.

The Impact of Inotropes and Vasopressors on Cerebral Oxygenation in Patients with Traumatic Brain Injury and Subarachnoid Hemorrhage: A Narrative Review

Traumatic brain injury (TBI) and subarachnoid hemorrhage (SAH) are critical neurological conditions that necessitate specialized care in the Intensive Care Unit (ICU). Managing cerebral perfusion pressure (CPP) and mean arterial pressure (MAP) is of primary importance in these patients. To maintain targeted MAP and CPP, vasopressors and/or inotropes are commonly used. However, their effects on cerebral oxygenation are not fully understood. The aim of this review is to provide an up-to date review regarding the current uses and pathophysiological issues related to the use of vasopressors and inotropes in TBI and SAH patients. According to our findings, despite achieving similar hemodynamic parameters and CPP, the effects of various vasopressors and inotropes on cerebral oxygenation, local CBF and metabolism are heterogeneous. Therefore, a more accurate understanding of the cerebral activity of these medications is crucial for optimizing patient management in the ICU setting.

Prophylactic use of levosimendan in preoperative setting for surgical repair of congenital heart disease in children

Introduction

Low cardiac output syndrome (LCOS) is a significant cause of morbidity and the leading cause of mortality after pediatric cardiac surgery. Levosimendan has been shown safe and effective in pediatrics to treat LCOS. We aimed to review our local strategy with preoperative prophylactic Levosimendan infusion to minimize LCOS after heart surgery in identified high-risk patients.

Methods

Retrospective monocentric study. As there is no reliable cardiac output measurement in children, we recorded hemodynamic parameters as surrogates of cardiac output after extracorporeal circulation through an electronic patient survey system at different time points.

Results

Seventy-two children received Levosimendan before surgery between 2010 and 2019. As expected, most patients were newborns and infants with prolonged open-heart surgeries. Median cardiopulmonary bypass time was 182 [137-234] min, and aortic clamping time was 95 [64-126] min. The postoperative hemodynamic parameters, vasoactive-inotropic score, and urine output remained stable throughout the first 48 h. Only a tiny portion of the patients had combined surrogate markers of LCOS with a maximal median arterial lactate of 2.6 [1.9-3.5] mmol/L during the first six postoperative hours, which then progressively normalized. The median arterio-venous difference in oxygen saturation was 31 [23-38] % between 12 and 18 h post-surgery and gradually decreased. The median venous-to-arterial CO2 difference was the highest at 10 [7-12] mmHg between 12 and 18 h post-surgery. Nine patients (13%) required extracorporeal membrane oxygenation. No patient required dialysis or hemofiltration. Mortality was 0%.

Conclusion

Before congenital heart surgery, preoperative prophylactic administration of Levosimendan seems effective and safe for decreasing occurrence and duration of LCOS in high-risk children.

Technologies for Direct Detection of Covalent Protein—Drug Adducts

In the past two decades, drug candidates with a covalent binding mode have gained the interest of medicinal chemists, as several covalent anticancer drugs have successfully reached the clinic. As a covalent binding mode changes the relevant parameters to rank inhibitor potency and investigate structure-activity relationship (SAR), it is important to gather experimental evidence on the existence of a covalent protein–drug adduct. In this work, we review established methods and technologies for the direct detection of a covalent protein–drug adduct, illustrated with examples from (recent) drug development endeavors. These technologies include subjecting covalent drug candidates to mass spectrometric (MS) analysis, protein crystallography, or monitoring intrinsic spectroscopic properties of the ligand upon covalent adduct formation. Alternatively, chemical modification of the covalent ligand is required to detect covalent adducts by NMR analysis or activity-based protein profiling (ABPP). Some techniques are more informative than others and can also elucidate the modified amino acid residue or bond layout. We will discuss the compatibility of these techniques with reversible covalent binding modes and the possibilities to evaluate reversibility or obtain kinetic parameters. Finally, we expand upon current challenges and future applications. Overall, these analytical techniques present an integral part of covalent drug development in this exciting new era of drug discovery.

Targeting the sarcomere in inherited cardiomyopathies

Variants in >12 genes encoding sarcomeric proteins can cause various cardiomyopathies. The two most common are hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM). Current therapeutics do not target the root causes of these diseases, but attempt to prevent disease progression and/or to manage symptoms. Accordingly, novel approaches are being developed to treat the cardiac muscle dysfunction directly. Challenges to developing therapeutics for these diseases include the diverse mechanisms of pathogenesis, some of which are still being debated and defined. Four small molecules that modulate the myosin motor protein in the cardiac sarcomere have shown great promise in the settings of HCM and DCM, regardless of the underlying genetic pathogenesis, and similar approaches are being developed to target other components of the sarcomere. In the setting of HCM, mavacamten and aficamten bind to the myosin motor and decrease the ATPase activity of myosin. In the setting of DCM, omecamtiv mecarbil and danicamtiv increase myosin activity in cardiac muscle (but omecamtiv mecarbil decreases myosin activity in vitro). In this Review, we discuss the therapeutic strategies to alter sarcomere contractile activity and summarize the data indicating that targeting one protein in the sarcomere can be effective in treating patients with genetic variants in other sarcomeric proteins, as well as in patients with non-sarcomere-based disease.

Effects of Levosimendan on Systemic Perfusion in Patients with Low Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) Score: Experience from a Single Center in Taiwan

Background

Patients with cardiogenic shock have a high risk of mortality. Intravenous levosimendan can provide pharmacologic inotrope support.

Objectives

We aimed to investigate the effect of levosimendan in patients with extremely severe cardiogenic shock and low Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) score with or without mechanical circulatory support.

Methods

From January 2017 to May 2019, 24 patients with INTERMACS 1-4 were enrolled in this retrospective study. All patients had systemic malperfusion and were treated with levosimendan. Biochemistry data related to systemic perfusion were recorded and compared before and at 24 and 72 hours after levosimendan administration. Echocardiography and Kansas City Cardiomyopathy Questionnaire (KCCQ) were completed 2 months later to assess left ventricular ejection fraction (LVEF) and quality of life (QoL), respectively.

Results

Arterial pressure and heart rate did not significantly differ before and after levosimendan administration. Atrial fibrillation and ventricular premature complex increased without significance. The dose of inotropes could be significantly tapered down. There were no significant differences in blood urea nitrogen, creatinine, and lactate levels. Urine output significantly increased (p = 0.018), and liver-related enzymes improved but without significance. B-type natriuretic peptide significantly decreased (p = 0.007) at 24 hours after levosimendan administration. Echocardiography showed significantly improved LVEF 2 months later (22.43 ± 8.13% to 35.87 ± 13.4%, p = 0.001). KCCQ showed significantly improved physical activity and greater relief of symptoms (p = 0.003). The survival-to-discharge rate was 75%.

Conclusions

We observed a decrease in B-type natriuretic peptide, better urine output, and alleviated hepatic injury in the levosimendan group. Most patients who survived without transplantation had significantly improved LVEF and better QoL after levosimendan administration.

Effect of Levosimendan Treatment in Pediatric Patients With Cardiac Dysfunction: An Update of a Systematic Review and Meta-Analysis of Randomized Controlled Trials

Levosimendan increasingly has been used to treat heart failure and cardiac dysfunction in pediatric patients. Currently, there is only limited evidence that this drug positively affects outcomes. The authors' aim was to investigate the effects of levosimendan on hemodynamic parameters and outcomes in pediatric patients in all clinical settings. The study design was a systematic review of randomized and nonrandomized studies. Randomized clinical trials (RCTs) were included in a meta-analysis. The primary outcome of the meta-analysis was the effect of levosimendan on central venous oxygen saturation (ScvO₂) and lactate values as surrogate markers of low-cardiac-output syndrome. The study setting was any acute care setting. Study participants were pediatric patients (age <18 years) receiving levosimendan, and the intervention was levosimendan versus any control treatment. The authors identified 44 studies published from 2004 to 2020, including a total of 1,131 pediatric patients. Nine studies (enrolling 547 patients) were RCTs, all performed in a pediatric cardiac surgery setting. Three RCTs were judged to carry a low risk of bias. In the RCTs, levosimendan administration was associated with a significant improvement of ScvO₂ (p = 0.03) and a trend toward lower postoperative lactate levels (p = 0.08). No differences could be found for secondary outcomes. Levosimendan use in pediatric patients is not associated with major side effects and may lead to hemodynamic improvement after cardiac surgery. However, its impact on major clinical outcomes remains to be determined. Overall, the quality of evidence for levosimendan use in pediatric patients is low, and further high-quality RCTs are needed.

A Potent Fluorescent Reversible-Covalent Inhibitor of Cardiac Muscle Contraction

Compounds that directly modulate the response of the cardiac sarcomere have potential in the treatment of cardiac disease. While a number of sarcomere activators have been discovered and extensively studied, very few inhibitors have been identified. We report a potent cardiac sarcomere inhibitor, DN-F01, targeting the cardiac muscle thin filament protein troponin complex. Functional studies show that DN-F01 has a strong inhibitory calcium-dependent effect on cardiac myofibrillar ATPase activity with an IC₅₀ value of 11 ± 4 nmol/L. DN-F01 is shown to bind to a cardiac troponin C-troponin I chimera (cChimera) with a K _D of ∼50 nM using fluorescence spectroscopy, indicating that troponin is the likely target for DN-F01. NMR titrations of DN-F01 to C35S and A-Cys cChimera show covalent and noncovalent binding of DN-F01 bound to the calcium-saturated cChimera.

[Levosimendan - a 20-Year Experience]

Levosimendan is a calcium sensitizer and opens adenosine triphosphate-dependent potassium channels. Since 20 years, it is approved for acute decompensated heart failure. It has been tested in many clinical trials for treatment of at-risk patients in cardiac surgery, right ventricular failure, pulmonary hypertension, weaning of extracorporeal systems, cardiogenic shock, septic shock, ARDS and others.Levosimendan has diverse positive effects next to positive inotropy. It improves ventriculoarterial coupling, increases peripheral perfusion, increases kidney glomerular filtration rate, coronary blood flow and it reduces preload and afterload as well as pulmonary capillary wedge pressure.Due to the opening of potassium channels, it also acts on mitochondria resulting in organ protection. Levosimendan acts anti-apoptotic. These positive effects were described in many small studies. Although this sounds like a promising drug for a variety of settings, results of several multicentre randomized placebo-controlled studies were frustrating. This review resumes some facts of levosimendan in different diseases.

An update on levosimendan in acute cardiac care: applications and recommendations for optimal efficacy and safety

Introduction: In the 20 years since its introduction to the palette of intravenous hemodynamic therapies, the inodilator levosimendan has established itself as a valuable asset for the management of acute decompensated heart failure. Its pharmacology is notable for delivering inotropy via calcium sensitization without an increase in myocardial oxygen consumption.Areas covered: Experience with levosimendan has led to its applications expanding into perioperative hemodynamic support and various critical care settings, as well as an array of situations associated with acutely decompensated heart failure, such as right ventricular failure, cardiogenic shock with multi-organ dysfunction, and cardio-renal syndrome. Evidence suggests that levosimendan may be preferable to milrinone for patients in cardiogenic shock after cardiac surgery or for weaning from extracorporeal life support and may be superior to dobutamine in terms of short-term survival, especially in patients on beta-blockers. Positive effects on kidney function have been noted, further differentiating levosimendan from catecholamines and phosphodiesterase inhibitors.Expert opinion:Levosimendan can be a valuable resource in the treatment of acute cardiac dysfunction, especially in the presence of beta-blockers or ischemic cardiomyopathy. When attention is given to avoiding or correcting hypovolemia and hypokalemia, an early use of the drug in the treatment algorithm is preferred.

Small Molecules acting on Myofilaments as Treatments for Heart and Skeletal Muscle Diseases

Hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM) are the most prevalent forms of the chronic and progressive pathological condition known as cardiomyopathy. These diseases have different aetiologies; however, they share the feature of haemodynamic abnormalities, which is mainly due to dysfunction in the contractile proteins that make up the contractile unit known as the sarcomere. To date, pharmacological treatment options are not disease-specific and rather focus on managing the symptoms, without addressing the disease mechanism. Earliest attempts at improving cardiac contractility by modulating the sarcomere indirectly (inotropes) resulted in unwanted effects. In contrast, targeting the sarcomere directly, aided by high-throughput screening systems, could identify small molecules with a superior therapeutic value in cardiac muscle disorders. Herein, an extensive literature review of 21 small molecules directed to five different targets was conducted. A simple scoring system was created to assess the suitability of small molecules for therapy by evaluating them in eight different criteria. Most of the compounds failed due to lack of target specificity or poor physicochemical properties. Six compounds stood out, showing a potential therapeutic value in HCM, DCM or heart failure (HF). Omecamtiv Mecarbil and Danicamtiv (myosin activators), Mavacamten, CK-274 and MYK-581 (myosin inhibitors) and AMG 594 (Ca²⁺-sensitiser) are all small molecules that allosterically modulate troponin or myosin. Omecamtiv Mecarbil showed limited efficacy in phase III GALACTIC-HF trial, while, results from phase III EXPLORER-HCM trial were recently published, indicating that Mavacamten reduced left ventricular outflow tract (LVOT) obstruction and diastolic dysfunction and improved the health status of patients with HCM. A novel category of small molecules known as “recouplers” was reported to target a phenomenon termed uncoupling commonly found in familial cardiomyopathies but has not progressed beyond preclinical work. In conclusion, the contractile apparatus is a promising target for new drug development.

An evidence-based review of the use of vasoactive and inotropic medications in post-operative paediatric patients after cardiac surgery with cardiopulmonary bypass from 2000 to 2020

BACKGROUND

Infants with moderate-to-severe CHD frequently undergo cardiopulmonary bypass surgery in childhood. Morbidity and mortality are highest in those who develop post-operative low cardiac output syndrome. Vasoactive and inotropic medications are mainstays of treatment for these children, despite limited evidence supporting their use.

METHODS

To help inform clinical practice, as well as the conduct of future trials, we performed a systematic review of existing literature on inotropes and vasoactives in children after cardiac surgery using the PubMed and EMBASE databases. We included studies from 2000 to 2020, and the patient population was defined as birth - 18 years of age. Two reviewers independently reviewed studies to determine final eligibility.

RESULTS

The final analysis included 37 papers. Collectively, selected studies reported on 12 different vasoactive and inotropic medications in 2856 children. Overall evidence supporting the use of these drugs in children after cardiopulmonary bypass was limited. The majority of studies were small with 30/37 (81%) enrolling less than 100 patients, 29/37 (78%) were not randomised, and safety and efficacy endpoints differed widely, limiting the ability to combine data for meta-analyses.

CONCLUSION

Vasoactive and inotropic support remain critical parts of post-operative care for children after cardiopulmonary bypass surgery. There is a paucity of data for the selection and dosing of vasoactives and inotropes for these patients. Despite the knowledge gaps that remain, numerous recent innovations create opportunities to rethink the conduct of clinical trials in this high-risk population.

[Individualized use of levosimendan in cardiac surgery]

BACKGROUND

Levosimendan is a cardiac inotrope that augments myocardial contractility without increasing myocyte oxygen consumption. Additionally, levosimendan has been shown to exhibit anti-inflammatory, antioxidative, and other cardioprotective properties and is approved for treatment of heart failure. Recent studies indicated that these beneficial effects can be achieved with doses lower than the standard dose of 12.5 mg. Patients with preoperatively diagnosed left ventricular ejection fraction (LVEF) ≤40% received 1.25 mg levosimendan after induction of anesthesia. After surgery, administration of low-dose levosimendan was repeated until cardiovascular stability was achieved.

OBJECTIVE

This study aimed to evaluate if pharmacological preconditioning with 1.25 mg levosimendan in patients with LVEF ≤40% altered the postoperative need for inotropic agents, the incidence of newly occurring atrial fibrillation, renal replacement therapy, mechanical circulatory support and 30-day mortality. The cumulative dosage of levosimendan was recorded to assess the required dosage in the context of individualized treatment.

MATERIAL AND METHODS

This retrospective study included patients with preoperatively diagnosed LVEF ≤40% who underwent cardiac surgery at this institution between January 2015 and December 2018 and who received 1.25 mg levosimendan after induction of anesthesia to prevent postoperative low cardiac output syndrome. Based on echocardiography results, invasive hemodynamic monitoring, and central venous or mixed venous oxygen saturation and lactate clearance, repetitive doses of levosimendan in 1.25 mg increments could be postoperatively administered until cardiovascular stability was achieved. The results were compared to the current literature.

RESULTS

We identified 183 patients with LVEF <40% who received pharmacological preconditioning with 1.25 mg levosimendan. Maximum doses of epinephrine, incidence of atrial fibrillation, need for renal replacement therapy and 30-day mortality were found to be below the published rates of comparable patient collectives. In 73.2% of patients, a cumulative dosage of 5 mg levosimendan or less was considered sufficient.

CONCLUSION

The presented concept of pharmacological preconditioning with 1.25 mg levosimendan followed by individualized additional dosing in cardiac surgery patients with preoperative LVEF ≤40% suggests that this concept is safe, with possible advantages regarding the need of inotropic agents, renal replacement therapy, and 30-day mortality, compared to the current literature. Individualized treatment with levosimendan to support hemodynamics and a timely reduction of inotropic agents needs further confirmation in randomized trials.

Potential of the Cardiovascular Drug Levosimendan in the Management of Amyotrophic Lateral Sclerosis: An Overview of a Working Hypothesis

Levosimendan is a calcium sensitizer that promotes myocyte contractility through its calcium-dependent interaction with cardiac troponin C. Administered intravenously, it has been used for nearly 2 decades to treat acute and advanced heart failure and to support the heart function in various therapy settings characterized by low cardiac output. Effects of levosimendan on noncardiac muscle suggest a possible new application in the treatment of people with amyotrophic lateral sclerosis (ALS), a neuromuscular disorder characterized by progressive weakness, and eventual paralysis. Previous attempts to improve the muscle response in ALS patients and thereby maintain respiratory function and delay progression of disability have produced some mixed results. Continuing this line of investigation, levosimendan has been shown to enhance in vitro the contractility of the diaphragm muscle fibers of non-ALS patients and to improve in vivo diaphragm neuromuscular efficiency in healthy subjects. Possible positive effects on respiratory function in people with ALS were seen in an exploratory phase 2 study, and a phase 3 clinical trial is now underway to evaluate the potential benefit of an oral form of levosimendan on both respiratory and overall functions in patients with ALS. Here, we will review the various known pharmacologic effects of levosimendan, considering their relevance to people living with ALS.

Levosimendan Efficacy and Safety: 20 years of SIMDAX in Clinical Use

Levosimendan was first approved for clinic use in 2000, when authorisation was granted by Swedish regulatory authorities for the haemodynamic stabilisation of patients with acutely decompensated chronic heart failure. In the ensuing 20 years, this distinctive inodilator, which enhances cardiac contractility through calcium sensitisation and promotes vasodilatation through the opening of adenosine triphosphate-dependent potassium channels on vascular smooth muscle cells, has been approved in more than 60 jurisdictions, including most of the countries of the European Union and Latin America. Areas of clinical application have expanded considerably and now include cardiogenic shock, takotsubo cardiomyopathy, advanced heart failure, right ventricular failure and pulmonary hypertension, cardiac surgery, critical care and emergency medicine. Levosimendan is currently in active clinical evaluation in the US. Levosimendan in IV formulation is being used as a research tool in the exploration of a wide range of cardiac and non-cardiac disease states. A levosimendan oral form is at present under evaluation in the management of amyotrophic lateral sclerosis. To mark the 20 years since the advent of levosimendan in clinical use, 51 experts from 23 European countries (Austria, Belgium, Croatia, Cyprus, Czech Republic, Estonia, Finland, France, Germany, Greece, Hungary, Italy, the Netherlands, Norway, Poland, Portugal, Russia, Slovenia, Spain, Sweden, Switzerland, UK and Ukraine) contributed to this essay, which evaluates one of the relatively few drugs to have been successfully introduced into the acute heart failure arena in recent times and charts a possible development trajectory for the next 20 years.

Levosimendan Efficacy and Safety: 20 Years of SIMDAX in Clinical Use

Levosimendan was first approved for clinical use in 2000, when authorization was granted by Swedish regulatory authorities for the hemodynamic stabilization of patients with acutely decompensated chronic heart failure (HF). In the ensuing 20 years, this distinctive inodilator, which enhances cardiac contractility through calcium sensitization and promotes vasodilatation through the opening of adenosine triphosphate-dependent potassium channels on vascular smooth muscle cells, has been approved in more than 60 jurisdictions, including most of the countries of the European Union and Latin America. Areas of clinical application have expanded considerably and now include cardiogenic shock, takotsubo cardiomyopathy, advanced HF, right ventricular failure, pulmonary hypertension, cardiac surgery, critical care, and emergency medicine. Levosimendan is currently in active clinical evaluation in the United States. Levosimendan in IV formulation is being used as a research tool in the exploration of a wide range of cardiac and noncardiac disease states. A levosimendan oral form is at present under evaluation in the management of amyotrophic lateral sclerosis. To mark the 20 years since the advent of levosimendan in clinical use, 51 experts from 23 European countries (Austria, Belgium, Croatia, Cyprus, Czech Republic, Estonia, Finland, France, Germany, Greece, Hungary, Italy, the Netherlands, Norway, Poland, Portugal, Russia, Slovenia, Spain, Sweden, Switzerland, the United Kingdom, and Ukraine) contributed to this essay, which evaluates one of the relatively few drugs to have been successfully introduced into the acute HF arena in recent times and charts a possible development trajectory for the next 20 years.

Levosimendan Improves Oxidative Balance in Cardiogenic Shock/Low Cardiac Output Patients

The beneficial effects exerted by levosimendan against cardiac failure could be related to the modulation of oxidative balance. We aimed to examine the effects of levosimendan in patients with cardiogenic shock or low cardiac output on cardiac systo-diastolic function and plasma oxidants/antioxidants (glutathione, GSH; thiobarbituric acid reactive substances, TBARS). In four patients undergoing coronary artery bypass grafting or angioplasty, cardiovascular parameters and plasma GSH and TBARS were measured at T0 (before levosimendan infusion), T1 (1 h after the achievement of the therapeutic dosage of levosimendan), T2 (end of levosimendan infusion), T3 (72 h after the end of levosimendan infusion), and T4 (end of cardiogenic shock). We found an improvement in the indices of systolic (ejection fraction, cardiac output, cardiac index) and diastolic (E to early diastolic mitral annular tissue velocity, E/'; early to late diastolic transmitral flow velocity, EA) cardiac function at early T2. A reduction of central venous pressure and pulmonary wedge pressure was also observed. Plasma levels of GSH and TBARS were restored by levosimendan at T1, as well. The results obtained indicate that levosimendan administration can regulate oxidant/antioxidant balance as an early effect in cardiogenic shock/low cardiac output patients. Modulation of oxidative status on a mitochondrial level could thus play a role in exerting the cardio-protection exerted by levosimendan in these patients.

Cardiac Inotropes Offer Protection of Renal Function in Patients with Kidney Transplantation

INTRODUCTION

Impaired cardiac function is one of the most concomitant symptoms in patients with kidney failure after long-term dialysis. In addition, the preservation of adequate perfusion pressure to the graft plays a significant role in the intraoperative management during kidney transplantation, but the use of positive inotropic drugs in kidney transplant patients has been studied less. We investigated the protective effects of renal function by means of cardiac inotropes in kidney transplant patients.

METHODS

Eighty-nine patients that received kidney transplantation between April 2014 and December 2016 at Qilu Hospital were included and randomly divided into the treatment group receiving levosimendan and a control group. All kidney recipients received ABO-compatible donors. A poor outcome was defined as one of the following: delayed graft function, graft hemorrhage, or nephrectomy.

RESULTS

The treatment group had a better composite outcome and the level of neutrophil gelatinase-associated lipocalin was also lower than in the control group.

CONCLUSION

Inotropic drugs may play a protective role in renal function in kidney transplantation.

Use of Levosimendan in Intensive Care Unit Settings: An Opinion Paper

Levosimendan is an inodilator that promotes cardiac contractility primarily through calcium sensitization of cardiac troponin C and vasodilatation via opening of adenosine triphosphate–sensitive potassium (K_ATP) channels in vascular smooth muscle cells; the drug also exerts organ-protective effects through a similar effect on mitochondrial K_ATP channels. This pharmacological profile identifies levosimendan as a drug that may have applications in a wide range of critical illness situations encountered in intensive care unit medicine: hemodynamic support in cardiogenic or septic shock; weaning from mechanical ventilation or from extracorporeal membrane oxygenation; and in the context of cardiorenal syndrome. This review, authored by experts from 9 European countries (Austria, Belgium, Czech republic, Finland, France, Germany, Italy, Sweden, and Switzerland), examines the clinical and experimental data for levosimendan in these situations and concludes that, in most instances, the evidence is encouraging, which is not the case with other cardioactive and vasoactive drugs routinely used in the intensive care unit. The size of the available studies is, however, limited and the data are in need of verification in larger controlled trials. Some proposals are offered for the aims and designs of these additional studies.

The effects of levosimendan use on high-sensitivity C-reactive protein in patients with decompensated heart failure

Introduction

The present study was intended to investigate the effect of levosimendan on high-sensitivity C-reactive protein (hsCRP) levels in hospitalized patients with decompensated heart failure.

Material and methods

The present study was designed as a prospective controlled clinical trial. A total of 50 patients with decompensated heart failure who were admitted to our hospital were included in the present study. Patients with stage III–IV heart failure based on the New York Heart Association, with systolic blood pressure > 100 mm Hg and with left ventricular ejection fraction of < 35%, were selected for the study population. The selected patients were divided into groups, levosimendan and furosemide.

Results

There was no significant difference between the groups based on demographics, basal echocardiographic and basal laboratory data. No difference was determined in basal hsCRP (mg/l) levels between the group admitted levosimendan infusion and the furosemide group (9.99 ±6.2, 9.23 ±6.4, p = 0.66). However, the hsCRP levels measured at the 24^th h (38.34 ±32.1 vs. 12.97 ±12.3, p < 0.001), the 48^th h (31.13 ±29.9 vs. 12.44 ±10.1, p = 0.003) and the 72^nd h (27.41 ±26.9 vs. 9.89 ±8.4, p = 0.002) were significantly higher in the levosimendan infusion group than the furosemide group.

Conclusions

It was found that hsCRP levels were significantly higher in the levosimendan infusion group than the furosemide group. Such an outcome could be related to myocyte injury and/or the amplification of the inflammatory response due to levosimendan.

Use of levosimendan in acute and advanced heart failure: short review on available real-world data

Published data have shown potential advantages of levosimendan in the management of acute decompensated heart failure and advanced heart failure when standard medical therapies threaten hemodynamics and organ perfusion are unable to alleviate clinical symptoms. Levosimendan distinguishes itself from other catecholaminergic inotropes by its three mechanisms of action: positive inotropy, vasodilation, and cardioprotection. In addition, its pharmacokinetics allow for a longer duration of action from the metabolite OR1896 allowing for further cardiovascular therapeutic effects for several days, even after discontinuation of the parent drug.

Thioimidate Bond Formation between Cardiac Troponin C and Nitrile-containing Compounds

We have investigated the mechanism and reactivity of covalent bond formation between cysteine-84 of the regulatory domain of cardiac troponin C and compounds containing a nitrile moiety similar to the calcium sensitizer levosimendan. The results of modifications to the levosimendan framework ranged from a large increase in covalent bond formation to complete inactivity. We present the biological activity of one of the most potent compounds. Limitations, including compound solubility and degradation at acidic pH, have prevented thorough investigation of the potential of these compounds. Our studies reveal the efficacious nature of the malononitrile moiety in targeting cNTnC and its potential in future cardiotonic drug design.

Use of Levosimendan in Postoperative Setting After Surgical Repair of Congenital Heart Disease in Children

Low cardiac output is one of the most common complications after cardiac surgery. Levosimendan, a new inotrope agent, has been demonstrated in adult patient to be an effective treatment for this purpose when classical therapy is not effective. The aim of this study was to evaluate the effect of Levosimendan on cardiac output parameters in cardiac children with low cardiac output syndrome (LCOS.). We carried out a retrospective analysis on 62 children hospitalized in our pediatric intensive care unit (PICU) after cardiac surgery, which demonstrated LCOS not responding to classical catecholamine therapy and who received levosimendan as rescue therapy. LCOS parameters like diuresis, central venous oxygen saturation (SvO₂), venous-to-arterial CO₂ difference (∆avCO₂), and plasmatic lactate were compared before therapy and at 3, 6, 12, and 24 h after the beginning of the levosimendan infusion. We also analyzed the effect on the Vasoactive-inotropic score (VIS), adverse events, and mortality. After the beginning of levosimendan infusion, diuresis (1.1 vs. 3.5 ml/kg/h, p = 0.001) and SvO₂ (59.5 vs. 63.3%, p = 0.026) increased significantly during the 24 h of infusion, and at the same time, plasmatic lactate (2.3 vs. 1.3 mmol/l, p < 0.001) decreased. ∆avCO₂ (10.8 vs. 9.4 mmHg, p = 0.21) and the VIS (44.5 vs. 22.5, p = 0.143) also decreased, but not significantly. No side effects were noted. The mortality in this patient group was 16%. Levosimendan is an effective treatment in children presenting LCOS after congenital heart surgery. Our study confirms the improvement of cardiac output already shown in other pediatric studies, with no undesirable side effects.

Successful Identification of Cardiac Troponin Calcium Sensitizers Using a Combination of Virtual Screening and ROC Analysis of Known Troponin C Binders

Calcium-dependent cardiac muscle contraction is regulated by the protein complex troponin. Calcium binds to the N-terminal domain of troponin C (cNTnC) which initiates the process of contraction. Heart failure is a consequence of a disruption of this process. With the prevalence of this condition, a strong need exists to find novel compounds to increase the calcium sensitivity of cNTnC. Desirable are small chemical molecules that bind to the interface between cTnC and the cTnI switch peptide and exhibit calcium sensitizing properties by possibly stabilizing cTnC in an open conformation. To identify novel drug candidates, we employed a structure-based drug discovery protocol that incorporated the use of a relaxed complex scheme (RCS). In preparation for the virtual screening, cNTnC conformations were identified based on their ability to correctly predict known cNTnC binders using a receiver operating characteristics analysis. Following a virtual screen of the National Cancer Institute's Developmental Therapeutic Program database, a small number of molecules were experimentally tested using stopped-flow kinetics and steady-state fluorescence titrations. We identified two novel compounds, 3-(4-methoxyphenyl)-6,7-chromanediol (NSC600285) and 3-(4-methylphenyl)-7,8-chromanediol (NSC611817), that show increased calcium sensitivity of cTnC in the presence of the regulatory domain of cTnI. The effects of NSC600285 and NSC611817 on the calcium dissociation rate was stronger than that of the known calcium sensitizer bepridil. Thus, we identified a 3-phenylchromane group as a possible key pharmacophore in the sensitization of cardiac muscle contraction. Building on this finding is of interest to researchers working on development of drugs for calcium sensitization.

Inotropes and cardiorenal syndrome in acute heart failure - A retrospective comparative analysis

INTRODUCTION

Cardiorenal syndrome (CRS) is common in acute heart failure (AHF), and is associated with dire prognosis. Levosimendan, a positive inotrope that also has diuretic effects, may improve patients' renal profile. Published results are conflicting.

OBJECTIVES

We aimed to assess the incidence of CRS in AHF patients according to the inotrope used and to determine its predictors in order to identify patients who could benefit from the most renoprotective inotrope.

METHODS

In a retrospective study, 108 consecutive patients with AHF who required inotropes were divided into two groups according to the inotrope used (levosimendan vs. dobutamine). The primary endpoint was CRS incidence. Follow-up for mortality and readmission for AHF was conducted.

RESULTS

Seventy-one percent of the study population were treated with levosimendan and the remainder with dobutamine. No differences were found in heart failure etiology or chronic kidney disease. At admission, the dobutamine group had lower blood pressure; there were no differences in estimated glomerular filtration rate or cystatin C levels. The levosimendan group had lower left ventricular ejection fraction. CRS incidence was higher in the dobutamine group, and they more often had incomplete recovery of renal function at discharge. In multivariate analysis, cystatin C levels predicted CRS. The dobutamine group had higher in-hospital mortality, of which CRS and the inotrope used were predictors.

CONCLUSIONS

Levosimendan appears to have some renoprotective effect, as it was associated with a lower incidence of CRS and better recovery of renal function at discharge. Identification of patients at increased risk of renal dysfunction by assessing cystatin C may enable more tailored therapy, minimizing the incidence of CRS and its negative impact on outcome in AHF.

Decongestive effects of levosimendan in cardiogenic shock induced by postpartum cardiomyopathy

BACKGROUND

Catecholamines and/or levosimendan have been proposed for haemodynamic restoration during cardiogenic shock (CS). In CS induced by post-partum cardiomyopathy (PPCM), levosimendan might be particularly favourable. The aim of this study was to evaluate the haemodynamic and echocardiographic effects of levosimendan in patients with CS, in particular in patients with PPCM-induced CS.

METHODS

Twenty-eight patients with refractory CS were retrospectively included in the study. Among them, a cohort of 8 women with PPCM-induced CS was included. All patients were treated with levosimendan (loading dose followed by a continuous infusion for 24 h) and were invasively monitored, including a pulmonary artery catheter, for 48hours. Echocardiographic measurements were performed at baseline and during follow-up.

RESULTS

Significant improvements in haemodynamic parameters were observed 48 h after starting levosimendan. The cardiac index increased (+1.2±0.6L/min, P<0.001) and filling pressures decreased (pulmonary artery occlusion pressure, PAOP: -11.2±4.3mmHg, P<0.001; right-atrial pressure, RAP: -6.1±4.9mmHg, P<0.001). The left ventricular ejection fraction was significantly higher at 48 h compared to baseline (38% [34-46%] versus 27% [22-30%], P<0.001). Despite similar characteristics at baseline, in the subgroup of patients with PPCM, more profound decongestive effects at 48hours were observed: PAOP (13±2 versus 17±4mmHg, P=0.007) and RAP (12±4 versus 17±4mmHg, P=0.006) were significantly lower in the PPCM subgroup compared to the non-PPCM subgroup.

CONCLUSIONS

Haemodynamics and left-ventricular ejection fraction rapidly improved after treatment with levosimendan. In patients with PPCM-induced CS, a more profound reduction of congestion was observed.

[Use of levosimendan in children]

Levosimendan is a calcium-sensitizing drug with positive inotropic properties. As an inodilator, this molecule also has a vasodilation effect. While its efficacy has been demonstrated in the adult in the context of cardiac surgery, its pediatric use is still not widespread. Many studies have shown its safety of use in children, including in the newborn. Across the world, a growing number of teams use levosimendan to treat both acute and chronic heart failure. Through a review of the literature, we describe its pharmacodynamic effects, its current applications, and its perspectives of use in children.

ORM-3819 promotes cardiac contractility through Ca(2+) sensitization in combination with selective PDE III inhibition, a novel approach to inotropy

This study is the first pharmacological characterization of the novel chemical entity, ORM-3819 (L-6-{4-[N'-(4-Hydroxi-3-methoxy-2-nitro-benzylidene)-hydrazino]-phenyl}-5-methyl-4,5-dihydro-2H-pyridazin-3-one), focusing primarily on its cardiotonic effects. ORM-3819 binding to cardiac troponin C (cTnC) was confirmed by nuclear magnetic resonance spectroscopy, and a selective inhibition of the phosphodiesterase III (PDE III) isozyme (IC50=3.88±0.3 nM) was revealed during in vitro enzyme assays. The Ca(2+)-sensitizing effect of ORM-3819 was demonstrated in vitro in permeabilized myocyte-sized preparations from left ventricles (LV) of guinea pig hearts (ΔpCa50=0.12±0.01; EC50=2.88±0.14 µM). ORM-3819 increased the maximal rate of LV pressure development (+dP/dtmax) (EC50=8.9±1.7 nM) and LV systolic pressure (EC50=7.63±1.74 nM) in Langendorff-perfused guinea pig hearts. Intravenous administration of ORM-3819 increased LV+dP/dtmax (EC50=0.13±0.05 µM/kg) and improved the rate of LV pressure decrease (-dP/dtmax); (EC50=0.03±0.02 µM/kg) in healthy guinea pigs. In an in vivo dog model of myocardial stunning, ORM-3819 restored the depressed LV+dP/dtmax and improved % segmental shortening (%SS) in the ischemic area (to 18.8±3), which was reduced after the ischaemia-reperfusion insult (from 24.1±2.1 to 11.0±2.4). Our data demonstrate ORM-3819 as a potent positive inotropic agent exerting its cardiotonic effect by a cTnC-dependent Ca(2+)-sensitizing mechanism in combination with the selective inhibition of the PDE III isozyme. This dual mechanism of action results in the concentration-dependent augmentation of the contractile performance under control conditions and in the postischemic failing myocardium.

Probing the mechanism of cardiovascular drugs using a covalent levosimendan analog

One approach to improve contraction in the failing heart is the administration of calcium (Ca^2 +) sensitizers. Although it is known that levosimendan and other sensitizers bind to troponin C (cTnC), their in vivo mechanism is not fully understood. Based on levosimendan, we designed a covalent Ca^2 + sensitizer (i9) that targets C84 of cTnC and exchanged this complex into cardiac muscle. The NMR structure of the covalent complex showed that i9 binds deep in the hydrophobic pocket of cTnC. Despite slightly reducing troponin I affinity, i9 enhanced the Ca^2 + sensitivity of cardiac muscle. We conclude that i9 enhances Ca^2 + sensitivity by stabilizing the open conformation of cTnC. These findings provide new insights into the in vivo mechanism of Ca^2 + sensitization and demonstrate that directly targeting cTnC has significant potential in cardiovascular therapy.

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A Ca^2 + sensitizer, i9 was designed that forms a covalent bond with C84 of cTnC.

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i9 stabilized the open state of the N-domain of cTnC.

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The structure of the covalent cTnC-cTnI-i9 complex was solved by NMR.

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The structure showed that i9 binds deep in the hydrophobic pocket of cTnC.

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Despite slightly reducing cTnI affinity, i9 enhanced the Ca^2 + sensitivity of cardiac muscle.

Fluorescence Based Characterization of Calcium Sensitizer Action on the Troponin Complex

Calcium sensitizers enhance the transduction of the Ca(2+) signal into force within the heart and have found use in treating heart failure. However the mechanisms of action for most Ca(2+) sensitizers remain unclear. To address this issue an efficient fluorescence based approach to Ca(2+) sensitizer screening was developed which monitors cardiac troponin C's (cTnC's) hydrophobic cleft. This approach was tested on four common Ca(2+) -sensitizers, EMD 57033, levosimendan, bepridil and pimobendan with the aim of elucidating the mechanisms of action for each as well as proving the efficacy of the new screening method. Ca(2+) -titration experiments were employed to determine the effect on Ca(2+) sensitivity and cooperativity of cTnC opening, while stopped flow experiments were used to investigate the impact on cTnC relaxation kinetics. Bepridil was shown to increase the sensitivity of cTnC for Ca(2+) under all reconstitution conditions, sensitization by the other drugs was context dependent. Levosimendan and pimobendan reduced the rate of cTnC closing consistent with a stabilization of cTnC's open conformation while bepridil increased the rate of relaxation. Experiments were also run on samples containing cTnT(T204E), a known Ca(2+) -desensitizing phosphorylation mimic. Levosimendan, bepridil, and pimobendan were found to elevate the Ca(2+) -sensitivity of cTnT(T204E) containing samples in this context.

Inhibition of phosphodiesterase-3 by levosimendan is sufficient to account for its inotropic effect in failing human heart

BACKGROUND AND PURPOSE

Levosimendan is known as a calcium sensitizer, although it is also known to inhibit PDE3. We aimed to isolate each component and estimate their contribution to the increased cardiac contractility induced by levosimendan.

EXPERIMENTAL APPROACH

Contractile force was measured in electrically stimulated ventricular strips from explanted failing human hearts and left ventricular strips from normal male Wistar rats. PDE activity was measured in a two-step PDE activity assay on failing human ventricle.

KEY RESULTS

Levosimendan exerted a positive inotropic effect (PIE) reaching maximum at 10(-5)  M in ventricular strips from failing human hearts. In the presence of the selective PDE3 inhibitor cilostamide, the PIE of levosimendan was abolished. During treatment with a PDE4 inhibitor and a supra-threshold concentration of isoprenaline, levosimendan generated an amplified inotropic response. This effect was reversed by β-adrenoceptor blockade and undetectable in strips pretreated with cilostamide. Levosimendan (10(-6)  M) increased the potency of β-adrenoceptor agonists by 0.5 log units in failing human myocardium, but not in the presence of cilostamide. Every inotropic response to levosimendan was associated with a lusitropic response. Levosimendan did not affect the concentration-response curve to calcium in rat ventricular strips, in contrast to the effects of a known calcium sensitizer, EMD57033 [5-(1-(3,4-dimethoxybenzoyl)-1,2,3,4-tetrahydroquinolin-6-yl)-6-methyl-3,6-dihydro-2H-1,3,4-thiadiazin-2-one]. PDE activity assays confirmed that levosimendan inhibited PDE3 as effectively as cilostamide.

CONCLUSIONS AND IMPLICATIONS

Our results indicate that the PDE3-inhibitory property of levosimendan was enough to account for its inotropic effect, leaving a minor, if any, effect to a calcium-sensitizing component.

Structure and function of cardiac troponin C (TNNC1): Implications for heart failure, cardiomyopathies, and troponin modulating drugs

In striated muscle, the protein troponin complex turns contraction on and off in a calcium-dependent manner. The calcium-sensing component of the complex is troponin C, which is expressed from the TNNC1 gene in both cardiac muscle and slow-twitch skeletal muscle (identical transcript in both tissues) and the TNNC2 gene in fast-twitch skeletal muscle. Cardiac troponin C (cTnC) is made up of two globular EF-hand domains connected by a flexible linker. The structural C-domain (cCTnC) contains two high affinity calcium-binding sites that are always occupied by Ca(2+) or Mg(2+) under physiologic conditions, stabilizing an open conformation that remains anchored to the rest of the troponin complex. In contrast, the regulatory N-domain (cNTnC) contains a single low affinity site that is largely unoccupied at resting calcium concentrations. During muscle activation, calcium binding to cNTnC favors an open conformation that binds to the switch region of troponin I, removing adjacent inhibitory regions of troponin I from actin and allowing muscle contraction to proceed. Regulation of the calcium binding affinity of cNTnC is physiologically important, because it directly impacts the calcium sensitivity of muscle contraction. Calcium sensitivity can be modified by drugs that stabilize the open form of cNTnC, post-translational modifications like phosphorylation of troponin I, or downstream thin filament protein interactions that impact the availability of the troponin I switch region. Recently, mutations in cTnC have been associated with hypertrophic or dilated cardiomyopathy. A detailed understanding of how calcium sensitivity is regulated through the troponin complex is necessary for explaining how mutations perturb its function to promote cardiomyopathy and how post-translational modifications in the thin filament affect heart function and heart failure. Troponin modulating drugs are being developed for the treatment of cardiomyopathies and heart failure.

Targeting the sarcomere to correct muscle function

Various human diseases can disrupt the balance between muscle contraction and relaxation. Sarcomeric modulators can be used to readjust this balance either indirectly by intervening in signalling pathways or directly through interaction with the muscle proteins that control contraction. Such agents represent a novel approach to treating any condition in which striated muscle function is compromised, including heart failure, cardiomyopathies, skeletal myopathies and a wide range of neuromuscular conditions. Here, we review agents that modulate the mechanical function of the sarcomere, focusing on emerging compounds that target myosin or the troponin complex.

Peri-operative Levosimendan in Patients Undergoing Cardiac Surgery: An Overview of the Evidence

Levosimendan, a calcium sensitiser, has recently emerged as a valuable agent in the peri-operative management of cardiac surgery patients. Levosimendan is a calcium-sensitising ionodilator. By binding to cardiac troponin C and reducing its calcium-binding co-efficient, it enhances myofilament responsiveness to calcium and thus enhances myocardial contractility without increasing oxygen demand. Current evidence suggests that levosimendan enhances cardiac function after cardiopulmonary bypass in patients with both normal and reduced left ventricular function. In addition to being used as post-operative rescue therapy for low cardiac output syndrome, a pre-operative levosimendan infusion in high risk patients with poor cardiac function may reduce inotropic requirements, the need for mechanical support, the duration of intensive care admissions as well as post-operative mortality. Indeed, it is these higher-risk patients who may experience a greater degree of benefit. Larger, multicentre randomised trials in cardiac surgery will help to elucidate the full potential of this agent.

The inotropic effect of the active metabolite of levosimendan, OR-1896, is mediated through inhibition of PDE3 in rat ventricular myocardium

Aims

We recently published that the positive inotropic response (PIR) to levosimendan can be fully accounted for by phosphodiesterase (PDE) inhibition in both failing human heart and normal rat heart. To determine if the PIR of the active metabolite OR-1896, an important mediator of the long-term clinical effects of levosimendan, also results from PDE3 inhibition, we compared the effects of OR-1896, a representative Ca²⁺ sensitizer EMD57033 (EMD), levosimendan and other PDE inhibitors.

Methods

Contractile force was measured in rat ventricular strips. PDE assay was conducted on rat ventricular homogenate. cAMP was measured using RII_epac FRET-based sensors.

Results

OR-1896 evoked a maximum PIR of 33±10% above basal at 1 μM. This response was amplified in the presence of the PDE4 inhibitor rolipram (89±14%) and absent in the presence of the PDE3 inhibitors cilostamide (0.5±5.3%) or milrinone (3.2±4.4%). The PIR was accompanied by a lusitropic response, and both were reversed by muscarinic receptor stimulation with carbachol and absent in the presence of β-AR blockade with timolol. OR-1896 inhibited PDE activity and increased cAMP levels at concentrations giving PIRs. OR-1896 did not sensitize the concentration-response relationship to extracellular Ca²⁺. Levosimendan, OR-1896 and EMD all increased the sensitivity to β-AR stimulation. The combination of either EMD and levosimendan or EMD and OR-1896 further sensitized the response, indicating at least two different mechanisms responsible for the sensitization. Only EMD sensitized the α₁-AR response.

Conclusion

The observed PIR to OR-1896 in rat ventricular strips is mediated through PDE3 inhibition, enhancing cAMP-mediated effects. These results further reinforce our previous finding that Ca²⁺ sensitization does not play a significant role in the inotropic (and lusitropic) effect of levosimendan, nor of its main metabolite OR-1896.

Versatile cardiac troponin chimera for muscle protein structural biology and drug discovery

Investigation of the molecular interactions within and between subunits of the heterotrimeric troponin complex, and with other proteins in the sarcomere, has revealed salient structural elements involved in regulation of muscle contraction. The discovery of new cardiotonic drugs and structural studies utilizing intact troponin, or regulatory complexes formed between the key regions identified in troponin C and troponin I, face intrinsic and technical difficulties associated with weak protein-protein interactions and with solubility, aggregation, stability of the overall architecture, isotope labeling, and size, respectively. We have designed and characterized a chimeric troponin C-troponin I hybrid protein with a cleavable linker that is useful for producing isotopically labeled troponin peptides, stabilizes their interaction, and has proven to be a faithful representation of the original complex in the systolic state, but lacking its disadvantages, making it particularly suitable for drug screening and structural studies.

Desensitization of myofilaments to Ca2+ as a therapeutic target for hypertrophic cardiomyopathy with mutations in thin filament proteins

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is a common genetic disorder caused mainly by mutations in sarcomeric proteins and is characterized by maladaptive myocardial hypertrophy, diastolic heart failure, increased myofilament Ca(2+) sensitivity, and high susceptibility to sudden death. We tested the following hypothesis: correction of the increased myofilament sensitivity can delay or prevent the development of the HCM phenotype.

METHODS AND RESULTS

We used an HCM mouse model with an E180G mutation in α-tropomyosin (Tm180) that demonstrates increased myofilament Ca(2+) sensitivity, severe hypertrophy, and diastolic dysfunction. To test our hypothesis, we reduced myofilament Ca(2+) sensitivity in Tm180 mice by generating a double transgenic mouse line. We crossed Tm180 mice with mice expressing a pseudophosphorylated cardiac troponin I (S23D and S24D; TnI-PP). TnI-PP mice demonstrated a reduced myofilament Ca(2+) sensitivity compared with wild-type mice. The development of pathological hypertrophy did not occur in mice expressing both Tm180 and TnI-PP. Left ventricle performance was improved in double transgenic compared with their Tm180 littermates, which express wild-type cardiac troponin I. Hearts of double transgenic mice demonstrated no changes in expression of phospholamban and sarcoplasmic reticulum Ca(2+) ATPase, increased levels of phospholamban and troponin T phosphorylation, and reduced phosphorylation of TnI compared with Tm180 mice. Moreover, expression of TnI-PP in Tm180 hearts inhibited modifications in the activity of extracellular signal-regulated kinase and zinc finger-containing transcription factor GATA in Tm180 hearts.

CONCLUSIONS

Our data strongly indicate that reduction of myofilament sensitivity to Ca(2+) and associated correction of abnormal relaxation can delay or prevent development of HCM and should be considered as a therapeutic target for HCM.

Comparison of single-dose and repeated levosimendan infusion in patients with acute exacerbation of advanced heart failure

BACKGROUND

Levosimendan (LS) is a novel inodilator that improves cardiac performance, central hemodynamics, and symptoms of patients with decompensated chronic heart failure. The aim of this study was to compare the effects of single and repeated LS infusion on left ventricular performance, biomarkers, and neurohormonal activation in patients with acute heart failure.

MATERIAL AND METHODS

Twenty-nine consecutive patients with acute exacerbation of advanced heart failure were included in this study. LS was initiated as a bolus of 6 μg/kg followed by a continuous infusion of 0.1 μg/kg/min for 24 hours in both groups who received intravenous single and repeated (baseline and at 1 and 3 months) treatment. Physical examination, echocardiography, and biochemical tests (brain natriuretic peptide, tumour necrosis factor-alpha, interleukin-1beta, 2, and 6) were performed before treatment and on 3 day of the treatment. The last evaluation was performed at 6 month after the baseline treatment.

RESULTS

Twenty male and 9 female patients with mean age of 60.2 ± 7.4 years were included in this study. A significant improvement in New York Heart Association functional status and myocardial performance index was detected only in the repeated LS treated patients at 6 month compared to the pretreatment status (p=0.03 and p<0.001; respectively). In addition, a significant decrease in brain natriuretic peptide (p<0.01) and plasma interleukin-6 (p=0.05) levels were also achieved only in patients who were given repeated LS.

CONCLUSIONS

Our study showed that repeated LS treatment is more effective compared to the single dose LS treatment in improving clinical status, hemodynamic and laboratory parameters in patients with acute exacerbation of advanced heart failure.

Levosimendan: first in a new class of inodilator for acute and chronic severe heart failure

Heart failure is the most common malignant disease in the developed world. Levosimendan (Simdax) is a novel intravenous agent that exerts inotropic effects through sensitization of myofilaments to calcium and vasodilator effects by opening ATP-dependent potassium channels on vascular smooth muscle. Infusion of levosimendan increases cardiac output due to an increase in stroke volume and heart rate, with a fall in pulmonary capillary wedge pressure. It has an active metabolite with a half-life of about 80 h, therefore infusions of 6 to 24 h result in hemodynamic effects that persist for 7 to 10 days. Preliminary observations suggest that a single infusion of levosimendan lasting 6 to 24 h in patients with severe heart failure due to left ventricular systolic dysfunction results in hemodynamic changes, symptomatic benefit and a reduction in morbidity and mortality over the following 2 to 4 weeks compared with placebo in one study and with dobutamine in another. Long-term follow-up suggests no loss of this early benefit over 6 months. Levosimendan is licensed for the treatment of decompensated heart failure in many countries but not in North America. Further large trials are being conducted comparing levosimendan with placebo and with dobutamine in patients with severe heart failure and left ventricular systolic dysfunction. If these studies confirm the benefits of levosimendan, then it may become routine therapy for the management of severe heart failure.

Intermittent levosimendan improves mid-term survival in chronic heart failure patients: meta-analysis of randomised trials

AIMS

Standard inotropic treatment is often necessary in end-stage heart failure but may be harmful. We performed a meta-analysis of randomized controlled trials to investigate the effect of repeated administration of levosimendan on survival in patients with chronic heart failure.

METHODS AND RESULTS

Four investigators independently searched in CENTRAL, Google Scholar MEDLINE/PubMed, Scopus and the Cochrane Central Register of clinical trials to identify any randomized study ever performed with intermittent levosimendan intravenous administration in adult patients with chronic heart failure with no restrictions on dose or time of administration. Data from a total of 326 patients from six randomized controlled studies using intermittent levosimendan in a cardiological setting were included in the analysis. Levosimendan was associated with a significant reduction in mortality at the longest follow-up available [32 of 168 (19 %) in the levosimendan group 46 of 133 (35 %) in the control arm, RR = 0.55 (95 % CI 0.37-0.84), p for effect = 0 0.005, p for heterogeneity = 0.3, I (2) = 23.4 %, NNT = 6 with 5 studies included]. Brain natriuretic peptide values, ejection fraction and number of patients with New York Heart Association ≥ III status were similar in survivors of both groups.

CONCLUSIONS

A large randomized trial is necessary to confirm the promising beneficial effects of intermittent levosimendan administration on the mid-term survival of patients with chronic heart failure.

Levosimendan Use Decreases Atrial Fibrillation in Patients after Coronary Artery Bypass Grafting: A Pilot Study

Background: Atrial fibrillation (AF) often occurs after coronary artery bypass grafting (CABG) and can result in increased morbidity and mortality due to complications. In the present study, our goal was to investigate whether the use of levosimendan can reduce the frequency of AF after coronary artery bypass grafting in patients with poor left ventricle function. Material and Methods: To investigate the effectiveness of levosimendan in the prophylaxis of AF, we conducted a prospective, randomized, placebo-controlled clinical study on 200 consecutive patients in whom we performed elective CABG operations. Baseline characteristics were similar in both groups. A control group of 100 patients were treated with placebo (500 mL saline solution), whereas the levosimendan group (n = 100 patients) was treated with levosimendan. High-sensitivity C-reactive protein, cardiac troponin, and creatine kinase–MB levels were measured before surgery and 5 days postoperatively. Results: AF occurred in 12% of the levosimendan group and 36% of the control group. The occurrence of AF was significantly lower in the levosimendan group (P < 0.05). The duration of AF in the levosimendan group was significantly shorter than that in the control group (4.83 ± 1.12 and 6.50 ± 1.55 hours, respectively; P = 0.028). Our research showed that C-reactive protein was higher postoperatively in the control group than in the levosimendan group (P < 0.05). Conclusions: The incidence of postoperative AF in the levosimendan group was reduced significantly in patients with poor left ventricle function after CABG operations.

Pharmacology of levosimendan: inotropic, vasodilatory and cardioprotective effects

WHAT IS KNOWN AND OBJECTIVE

Positive inotropic agents are frequently used in acute decompensated heart failure (ADHF) due to left ventricular systolic dysfunction. These agents are known to improve cardiac performance and peripheral perfusion in the short-term treatment. However, several preclinical and clinical studies emphasized detrimental effects of these drugs on myocardial oxygen demand and on sympathetic tone entailing arrhythmogenesis. Levosimendan is an inotropic agent with an original mechanism of action. This review focuses on major data available for levosimendan.

METHODS

A literature search was conducted in the PubMed database by including studies published in English using combinations of the following key words, levosimendan, inotropic drugs and acute heart failure. Furthermore, bibliographies of selected references were also evaluated for relevant articles. The collection for this review was limited to the most recently available human and animal data.

RESULTS AND DISCUSSION

Levosimendan's vasodilatory and cardioprotective effects are mediated by calcium sensitization of contractile proteins and opening of adenosine triphosphate (ATP)-dependent K+ channels in vascular smooth muscle cells and on mitochondrial ATP-sensitive potassium [mito.K(ATP)] channels. This inotropic agent has mild PDE inhibitory action. Unlike other inotropic agents, levosimendan improves cardiac performance without activating the sympathetic nervous system. Moreover, there are evidences that levosimendan has additional anti-inflammatory and anti-apoptotic properties that prevent cardiac toxicity and contributes to positive hemodynamic response of the drug. Four randomized trials evaluated the effects of levosimendan on mortality in patients with acute decompensated chronic heart failure; nevertheless, a clear benefit has not been demonstrated so far. Although levosimendan is indicated for the treatment of ADHF (class of recommendation IIa, level of evidence B), it is has not been approved in all countries.

WHAT IS NEW AND CONCLUSION

This review summarizes the characteristics and the current knowledge of the literature on levosimendan and its active metabolite OR-1896.

Levosimendan: Implications for Clinicians

Levosimendan is a novel calcium sensitizing agent in development for the treatment of acute and chronic heart failure. The agent increases myocardial force without increasing myocyte calcium concentrations, thus reducing the possibility for myocardial necrosis. In addition, the agent also causes vasodilation of coronary and peripheral vessels to improve coronary blood flow and reduce afterload. The short half-life is a benefit for intravenous administration but could be problematic for the drug's use in chronic heart failure. The risk of the development of arrhythmias from levosimendan appears small secondary to an increase in the QTc interval of 15 msec but needs to be evaluated in light of the ability of levosimendan to open adenosine triphosphate (ATP)-sensitive potassium channels. In addition, the agent has not been studied in patients with additional risks for torsades de pointes. Levosimendan has been shown to have beneficial survival effects in several populations; its use improves patient outcomes relative to the standard of care and has the potential to reduce hospital costs associated with heart failure.

Rapid recovery from acute myocarditis under levosimendan treatment: report of two cases

WHAT IS KNOWN AND OBJECTIVES

Acute viral myocarditis (AVM) is an inflammatory heart disease that may lead to acute heart failure caused by cardiomyocyte loss. AVM may result in fatal outcome due to hemodynamic compromise. There is no specific treatment for AVM. Treatment is generally same as the treatment of conventional heart failure. Levosimendan is a new molecule with inotropic and vasodilator effect and is widely used for acute decompensated heart failure.

DETAILS OF THE CASES

Case 1: A 48-years-old, previously healthy male patient admitted to our clinic with complaints of acute onset of rest dyspnea and orthopnea, started the day before. Cardiac chambers were enlarged on echocardiography with global hypokinesia and ejection fraction (EF) was 25%. The patient was diagnosed as AVM complicated with decompensated heart failure. Continuous infusion of 0·2 μg/kg/min levosimendan for 24 h with treatment of conventional heart failure. Echocardiographic follow-up revealed a rapid improvement in left ventricular EF (50%) after 24 h. Case 2: A 33-years-old male patient admitted to our clinic with new onset shortness of breath and palpitation complaints. Echocardiography revealed enlarged left heart cavities with global hypocinesia (EF was 25%). The patient was diagnosed as AVM complicated with decompensated heart failure. Continuous infusion of 0·2 μg/kg/min levosimendan for 24 h with treatment of conventional heart failure. Echocardiography revealed dramatic improvement of left ventricular systolic function (EF = 55%) 24 h later.

WHAT IS NEW AND CONCLUSION

To our knowledge, there is no report or study on levosimendan therapy for AVM in humans to date. Herein, we share two cases that revealed dramatic improvement in the myocardial function with levosimendan usage during the early phase of AVM.