Serelaxin, recombinant human relaxin-2, for treatment of acute heart failure (RELAX-AHF): a randomised, placebo-controlled trial

Using the novel HiBiT tag to label cell surface relaxin receptors for BRET proximity analysis

Relaxin family peptide 1 (RXFP1) is the receptor for relaxin a peptide hormone with important therapeutic potential. Like many G protein-coupled receptors (GPCRs), RXFP1 has been reported to form homodimers. Given the complex activation mechanism of RXFP1 by relaxin, we wondered whether homodimerization may be explicitly required for receptor activation, and therefore sought to determine if there is any relaxin-dependent change in RXFP1 proximity at the cell surface. Bioluminescence resonance energy transfer (BRET) between recombinantly tagged receptors is often used in GPCR proximity studies. RXFP1 targets poorly to the cell surface when overexpressed in cell lines, with the majority of the receptor proteins sequestered within the cell. Thus, any relaxin-induced changes in RXFP1 proximity at the cell surface may be obscured by BRET signal originating from intracellular compartments. We therefore, utilized the newly developed split luciferase system called HiBiT to specifically label the extracellular terminus of cell surface RXFP1 receptors in combination with mCitrine-tagged receptors, using the GABAB heterodimer as a positive control. This demonstrated that the BRET signal detected from RXFP1-RXFP1 proximity at the cell surface does not appear to be due to stable physical interactions. The fact that there is also no relaxin-mediated change in RXFP1-RXFP1 proximity at the cell surface further supports these conclusions. This work provides a basis by which cell surface GPCR proximity and expression levels can be specifically studied using a facile and homogeneous labeling technique such as HiBiT.

Human recombinant relaxin-2 does not attenuate hypertension or renal injury but exacerbates vascular dysfunction in a female mouse model of SLE

Systemic lupus erythematosus (SLE) is an autoimmune disease that disproportionately affects women of reproductive age and increases their risk for developing hypertension, vascular, and renal disease. Relaxin has potential beneficial therapeutic effects in cardiovascular disease through direct actions on the vasculature. The potential therapeutic benefit of relaxin on SLE-associated cardiovascular and renal risk factors like hypertension has not previously been tested. We hypothesized that relaxin would attenuate hypertension, renal injury, and vascular dysfunction in an established female mouse model of SLE (NZBWF1 mice). Serelaxin (human recombinant relaxin-2, 0.5 mg·kg^-1·day^-1) or vehicle was administered via osmotic mini-pump for 4 wk in female control (NZW) or SLE mice between 28 and 31 wk of age. Serelaxin treatment increased uterine weights in both groups, suggesting that the Serelaxin was bioactive. Mean arterial pressure, measured by carotid artery catheter, was significantly increased in vehicle-treated SLE mice compared with vehicle-treated controls, but was not changed by Serelaxin treatment. Albumin excretion rate, measured by ELISA, was similar between vehicle- and Serelaxin-treated SLE mice and between vehicle- and Serelaxin-treated control mice. Wire myography was performed using isolated carotid arteries to assess endothelial-independent and -dependent vasodilation, and data confirm that SLE mice have impaired endothelium-independent and -dependent relaxation compared with control mice. Serelaxin treatment did not affect endothelium-independent vasodilation, but exacerbated the endothelium-dependent dysfunction. These data suggest that, contrary to our hypothesis, Serelaxin infusion does not attenuate hypertension, renal injury, or vascular dysfunction in SLE, but worsens underlying vascular endothelial dysfunction in this experimental model of SLE. These data do not support the use of human recombinant relaxin-2 as an antihypertensive in the SLE patient population. NEW & NOTEWORTHY Relaxin is a peptide hormone commonly known for its role in pregnancy and for its use in recent clinical trials for the treatment of heart failure. Evidence suggests that relaxin has immunomodulatory effects; however, the potential therapeutic impact of relaxin in chronic immune mediated disease is unclear. This study tests whether recombinant human relaxin (Serelaxin) attenuates the progression of autoimmunity, and the associated cardiovascular consequences, in an experimental model of systemic lupus erythematosus.

Implication of Acute Kidney Injury in Heart Failure

Patients with acute or chronic decompensated heart failure (ADHF) present with various degrees of heart and kidney dysfunction characterizing cardiorenal syndrome (CRS). CRS can be generally defined as a pathophysiologic disorder of the heart and kidneys whereby acute or chronic dysfunction of 1 organ may induce acute or chronic dysfunction of the other. ADHF is a challenge in the management of heart failure. This review provides an overview the pathophysiology of type 1 CRS together with new approaches to treatment in patients with heart failure with worsening renal function or acute kidney disease.

Relaxin gene delivery mitigates liver metastasis and synergizes with check point therapy

Activated hepatic stellate cell (aHSC)-mediated liver fibrosis is essential to the development of liver metastasis. Here, we discover intra-hepatic scale-up of relaxin (RLN, an anti-fibrotic peptide) in response to fibrosis along with the upregulation of its primary receptor (RXFP1) on aHSCs. The elevated expression of RLN serves as a natural regulator to deactivate aHSCs and resolve liver fibrosis. Therefore, we hypothesize this endogenous liver fibrosis repair mechanism can be leveraged for liver metastasis treatment via enforced RLN expression. To validate the therapeutic potential, we utilize aminoethyl anisamide-conjugated lipid-calcium-phosphate nanoparticles to deliver plasmid DNA encoding RLN. The nanoparticles preferentially target metastatic tumor cells and aHSCs within the metastatic lesion and convert them as an in situ RLN depot. Expressed RLN reverses the stromal microenvironment, which makes it unfavorable for established liver metastasis to grow. In colorectal, pancreatic, and breast cancer liver metastasis models, we confirm the RLN gene therapy results in significant inhibition of metastatic progression and prolongs survival. In addition, enforced RLN expression reactivates intra-metastasis immune milieu. The combination of the RLN gene therapy with PD-L1 blockade immunotherapy further produces a synergistic anti-metastatic efficacy. Collectively, the targeted RLN gene therapy represents a highly efficient, safe, and versatile anti-metastatic modality, and is promising for clinical translation.

Defining the role of peritoneal dialysis in management of congestive heart failure

Introduction: Congestion is an integral component of heart failure (HF) pathophysiology and portends an adverse impact on outcome. Peritoneal dialysis (PD) is a home-based therapeutic modality that has been used in the setting of refractory congestive HF to help optimize volume status. Not only does PD allow for customized sodium and water removal, but it also provides the opportunity for the patients to fully benefit from guideline-directed medical therapy for HF that could have otherwise been challenging to use. Areas covered: Authors provide an overview of the pathophysiologic basis for the use of PD in HF, followed by a review of the findings of the main clinical trials such as the salutary impact on HF re-admissions and quality of life. Since the goals of therapy in this setting differ from those for patients with end-stage renal disease, pertinent practical considerations in the use of this modality are then discussed as well as potential barriers. Expert opinion: For patients with chronic refractory HF, PD represents an alternative to medical therapy alone. Identification of patients that would benefit most from this modality and detection of major enablers and obstacles for the implementation of this therapy should be the focus of future studies.

TACIT (High Sensitivity Troponin T Rules Out Acute Cardiac Insufficiency Trial)

BACKGROUND

Identifying low-risk acute heart failure patients safe for discharge from the emergency department is a major unmet need.

METHODS AND RESULTS

A prospective, observational, multicenter pilot study targeting lower risk acute heart failure patients to determine whether hsTnT (high-sensitivity troponin T) identifies emergency department acute heart failure patients at low risk for rehospitalization and mortality. hsTnT was drawn at baseline and 3 hours. Phone follow-up occurred at 30 and 90 days. The primary end point composite of all-cause mortality, rehospitalization, and emergency department visits at 90 days (changed from 30 days because of lack of mortality events), analyzed using logistic regression. Secondary end points: 30- and 90-day all-cause mortality. hsTnT values less than the 99th percentile were defined as low hsTnT. Out of 527 enrolled patients, 499 comprised the initial analysis set. Of these, 332 had both 0- and 3-hour hsTnT drawn, of whom 319 completed 30 day follow-up. The average age was 62, 60% male, and 57% black. Median hsTnT was 26.4 ng/L (interquartile range, 15.1-44.3). There were 99 (21%) 30-day composite events, 13 (2.7%) deaths at 30 days, and 25 deaths (8.2%) at 90 days. Serial hsTnT values below the 99th percentile were not associated with a lower risk for the 90-day primary composite end point (odds ratio, 0.79; 95% CI, 0.42-1.50; P=0.4736). However, no deaths occurred in the low hsTnT group at 30 days with 1 death at 90 days.

CONCLUSIONS

hsTnT did not identify patients at low risk for the primary outcome of rehospitalization, emergency department visits, and mortality at 90 days.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov . Unique identifier: NCT02592135.

Therapeutic Advances in the Management of Acute Decompensated Heart Failure

BACKGROUND

Acute decompensated heart failure (ADHF) is the most common presenting phenotype of acute heart failure (AHF). The main goal of this article was to review the contemporary management strategies in these patients and to describe how future clinical trials may address unmet clinical needs.

AREAS OF UNCERTAINTY

The current pathophysiologic understanding of AHF is incomplete. The guideline recommendations for the management of ADHF are based only on algorithms provided by expert consensus guided by blood pressure and/or clinical signs of congestion or hypoperfusion. The lack of adequately conducted trials to address the unmet need for evidence therapy in AHF has not yet been surpassed, and at this time, there is no evidence-based strategy for targeted decongestive therapy to improve outcomes. The precise time point for initiation of guideline-directed medical therapies (GDMTs), as respect to moment of decompensation, is also unknown.

DATA SOURCES

The available data informing current management of patients with ADHF are based on randomized controlled trials, observational studies, and administrative databases.

THERAPEUTIC ADVANCES

A major step-forward in the management of ADHF patients is recognizing congestion, either clinical or hemodynamic, as a major trigger for heart failure (HF) hospitalization and most important target for therapy. However, a strategy based exclusively on congestion is not sufficient, and at present, comprehensive assessment during hospitalization of cardiac and noncardiovascular substrate with identification of potential therapeutic targets represents "the corner-stone" of ADHF management. In the last years, substantial data have emerged to support the continuation of GDMTs during hospitalization for HF decompensation. Recently, several clinical trials raised hypothesis of "moving to the left" concept that argues for very early implementation of GDMTs as potential strategy to improve outcomes.

CONCLUSIONS

The management of ADHF is still based on expert consensus documents. Further research is required to identify novel therapeutic targets, to establish the precise time point to initiate GDMTs, and to identify patients at risk of recurrent hospitalization.

Novel approaches to the management of chronic systolic heart failure: future directions and unanswered questions

Despite improvements in outcomes in the last few decades for heart failure (HF) with reduced ejection fraction (HFrEF), there still remains a need for novel therapies as many patients incompletely recover with existing therapies and progress to advanced HF. In this review, we will discuss recent advances in the management of HFrEF with a focus on upcoming therapies that hold the greatest promise for clinical use. We will discuss novel pharmacological therapies and areas of uncertainty with existing therapies. We will also discuss the potential utility and controversy surrounding novel interventions for HF such as percutaneous mitral valve repair, atrial fibrillation ablation, and other emerging interventions with positive signals for benefit in HFrEF. Finally, we will summarize the current state of stem cell and gene therapy for HFrEF and future directions.

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Circulating Relaxin-1 Level Is a Surrogate Marker of Myocardial Fibrosis in HFrEF

Introduction: Relaxin-1 (RLN1) has emerged as a possible therapeutic target in myocardial fibrosis due to its anti-fibrotic effects. Previous randomized clinical trials investigated therapeutic role of exogenous relaxin in patients with acute-on-chronic heart failure (HF) and failed to meet clinical endpoints. Here, we aimed to assess endogenous, circulating RLN1 levels in patients with heart failure with reduced ejection fraction (HFrEF) of ischemic origin. Furthermore, we analyzed relation of RLN1 and left ventricular diastolic function, left and right ventricular fibrosis, and invasive hemodynamic measurements. Unique feature of our study is the availability of ex vivo human myocardial tissue.

Methods: Human myocardial samples were available from the Transplantation Biobank of the Heart and Vascular Center at Semmelweis University after local ethical approval and informed consent of all participants (n = 47). Tissue was collected immediately after heart explantations; peripheral blood was collected before induction of anesthesia. Myocardial sections were stained for Masson’s trichrome and Picrosirius red staining to quantify fibrosis. Medical records were analyzed (ECG, anthropometry, blood tests, medication, echocardiography, and invasive hemodynamic measurements).

Results: Average RLN1 levels in HFrEF population were significantly higher than measured in age and gender matched healthy control human subjects (702 ± 283 pg/ml in HFrEF vs. 44 ± 27 pg/ml in control n = 47). We found a moderate inverse correlation between RLN1 levels and degree of myocardial fibrosis in both ventricles (r = −0.357, p = 0.014 in the right ventricle vs. r = −0.321, p = 0.028 in the left ventricle with Masson’s trichrome staining). Parallel, a moderate positive correlation was found in left ventricular diastolic function (echocardiography, E/A wave values) and RLN1 levels (r = 0.456, p = 0.003); a negative correlation with RLN1 levels and left ventricular end-systolic diameter (r = −0.373, p = 0.023), and diastolic pulmonary artery pressure (r = −0.894, p < 0.001). RLN1 levels showed moderate correlation with RLN2 levels (r = 0.453, p = 0.0003).

Conclusion: Increased RLN1 levels were accompanied by lower myocardial fibrosis rate, which is a novel finding in our patient population with coronary artery disease and HFrEF. RLN1 can have a biomarker role in ventricular fibrosis; furthermore, it may influence hemodynamic and vasomotor activity via neurohormonal mechanisms of action. Given these valuable findings, RLN1 may be targeted in anti-fibrotic therapeutics and in perioperative care of heart transplantation.

Leveraging Signaling Pathways to Treat Heart Failure With Reduced Ejection Fraction

Advances in the treatment of heart failure with reduced ejection fraction due to systolic dysfunction are engaging an ever-expanding compendium of molecular signaling targets. Well established approaches modifying hemodynamics and cell biology by neurohumoral receptor blockade are evolving, exploring the role and impact of modulating intracellular signaling pathways with more direct myocardial effects. Even well-tread avenues are being reconsidered with new insights into the signaling engaged and thus opportunity to treat underlying myocardial disease. This review explores therapies that have proven successful, those that have not, those that are moving into the clinic but whose utility remains to be confirmed, and those that remain in the experimental realm. The emphasis is on signaling pathways that are tractable for therapeutic manipulation. Of the approaches yet to be tested in humans, we chose those with a well-established experimental history, where clinical translation may be around the corner. The breadth of opportunities bodes well for the next generation of heart failure therapeutics.

High vs. low oxygen therapy in patients with acute heart failure: HiLo-HF pilot trial

Aims

Most patients with acute heart failure (AHF) are treated with supplemental oxygen during hospitalization. In this study, we investigated the effect of oxygen titrated to high vs. low pulse oximetry targets in patients hospitalized with AHF.

Methods and results

In a pilot, open‐label randomized controlled trial (RCT), 50 patients who were admitted with AHF were randomized to either high (≥96%) or low (90–92%) SpO₂ targets. Oxygen was manually titrated to the assigned target ranges for 72 h. The primary endpoint was the change in N‐terminal pro‐brain‐type natriuretic peptide (NT‐proBNP) from randomization to 72 h, and secondary endpoints included patient‐reported dyspnoea by visual analogue scale (VAS), patient global assessment (PGA), peak expiratory flow (PEF) within 72 h, and clinical outcomes up to 30 days following hospital discharge. The median age was 73.5 years, and 42% were women. The change in NT‐proBNP was −6963 (−13 345, −1253) pg/mL in the high SpO₂ group and −2093 (−5692, −353) pg/mL in the low SpO₂ group (P = 0.46), and the 72 h to baseline NT‐proBNP ratio was similar between groups (0.7 vs. 0.6, P = 0.51). There were no differences between arms in change in dyspnoea VAS (P = 0.86), PGA (P = 0.91), PEF (P = 0.52), in‐hospital mortality (4.0% vs. 8.0%, P = 0.50), or 30 day heart failure readmission rates (20.8% vs. 8.7%, P = 0.22).

Conclusions

In this study, no differences were observed in the primary or secondary outcomes for patients randomized to high vs. low SpO₂ targets. Further RCTs with larger sample sizes are warranted to determine the efficacy and safety of oxygen therapy in patients with AHF.

Healthy Donors Exhibit a CD4 T Cell Repertoire Specific to the Immunogenic Human Hormone H2-Relaxin before Injection

H2-relaxin (RLN2) is a two-chain peptide hormone structurally related to insulin with a therapeutic potential in multiple indications. However, multiple injections of human RLN2 induced anti-RLN2 Abs in patients, hampering its clinical development. As T cell activation is required to produce Abs, we wondered whether T cells specific for RLN2 might be already present in the human blood before any injection. We therefore quantified the RLN2-specific T cell repertoire using PBMCs collected from healthy donors. CD4 T cells were stimulated in multiple replicates by weekly rounds of stimulation by dendritic cells loaded with RLN2, and their specificity was assessed by IFN-γ ELISPOT. The number of specific T cell lines was used to estimate the frequency of circulating T cells. In vitro T cell response was demonstrated in 18 of the 23 healthy donors, leading to the generation of 70 independent RLN2-specific T cell lines. The mean frequency of RLN2-specific CD4 T cells was similar to that of T cells specific for known immunogenic therapeutic proteins. Using overlapping peptides, we identified multiple T cell epitopes hosted in the N-terminal parts of the α- and β-chains and common to multiple donors, in agreement with their capacity to bind to multiple HLA-DR molecules. Our results provide important clues to the immunogenicity of RLN2 and highlight the weak central immune tolerance induced against this self-hormone.

Serelaxin enhances the therapeutic effects of human amnion epithelial cell-derived exosomes in experimental models of lung disease

BACKGROUND AND PURPOSE

There is growing interest in stem cell-derived exosomes for their therapeutic and regenerative benefits given their manufacturing and regulatory advantages over cell-based therapies. As existing fibrosis impedes the viability and efficacy of stem cell/exosome-based strategies for treating chronic diseases, here we tested the effects of the anti-fibrotic drug, serelaxin, on the therapeutic efficacy of human amnion epithelial cell (AEC)-derived exosomes in experimental lung disease.

EXPERIMENTAL APPROACH

Female Balb/c mice were subjected to either the 9.5-week model of ovalbumin and naphthalene (OVA/NA)-induced chronic allergic airway disease (AAD) or 3-week model of bleomycin (BLM)-induced pulmonary fibrosis; then administered increasing concentrations of AEC-exosomes (5 μg or 25μg), with or without serelaxin (0.5mg/kg/day) for 7-days. 1x10⁶ AECs co-administered with serelaxin over the corresponding time-period were included for comparison in both models, as was pirfenidone-treatment of the BLM model. Control groups received saline/corn oil or saline, respectively.

KEY RESULTS

Both experimental models presented with significant tissue inflammation, remodelling, fibrosis and airway/lung dysfunction at the time-points studied. While AEC-exosome (5 μg or 25μg)-administration alone demonstrated some benefits in each model, serelaxin was required for AEC-exosomes (25μg) to rapidly normalise chronic AAD-induced airway fibrosis and airway reactivity, and BLM-induced lung inflammation, epithelial damage and subepithelial/basement membrane fibrosis. Combining serelaxin with AEC-exosomes (25μg) also demonstrated broader protection compared to co-administration of serelaxin with 1x10⁶ AECs or pirfenidone.

CONCLUSIONS AND IMPLICATIONS

Serelaxin enhanced the therapeutic efficacy of AEC-exosomes in treating basement membrane-induced fibrosis and related airway dysfunction.

Relaxin and fibrosis: Emerging targets, challenges, and future directions

The peptide hormone relaxin is well-known for its anti-fibrotic actions in several organs, particularly from numerous studies conducted in animals. Acting through its cognate G protein-coupled receptor, relaxin family peptide receptor 1 (RXFP1), serelaxin (recombinant human relaxin) has been shown to consistently inhibit the excessive extracellular matrix production (fibrosis) that results from the aberrant wound-healing response to tissue injury and/or chronic inflammation, and at multiple levels. Furthermore, it can reduce established scarring by promoting the degradation of aberrant extracellular matrix components. Following on from the review that describes the mechanisms and signaling pathways associated with the extracellular matrix remodeling effects of serelaxin (Ng et al., 2019), this review focuses on newly identified tissue targets of serelaxin therapy in fibrosis, and the limitations associated with (se)relaxin research.

Targeting the relaxin/insulin-like family peptide receptor 1 and 2 with small molecule compounds

The peptide hormone relaxin has beneficial roles in several organs through its action on its cognate G protein-coupled receptor, RXFP1. Relaxin administration is limited to intravenous, subcutaneous, intramuscular, or spinal injection. Another drawback of peptide-based therapy is the short half-life, which requires continuous delivery of the drug to achieve efficient concentration in target organs. The discovery of a non-peptide small molecule agonist of RXFP1, ML290, provides an alternative to the natural ligand. This review summarizes the development of ML290 and its potential future therapeutic applications in various diseases, including liver fibrosis and cardiovascular diseases. We also discuss the development of small molecule agonists targeting the insulin-like 3 receptor, RXFP2, and propose the potential use of these small molecules in the context of bone and muscle remodeling.

Relaxin-2 for heart failure with preserved ejection fraction (HFpEF): Rationale for future clinical trials

Heart Failure with preserved Ejection Fraction (HFpEF), a distinct sub-entity of chronic heart failure characterized by generalized inflammatory non-compliance of the cardio-vascular system, is associated with high mortality and still an unmet medical need. Many novel and promising therapeutic approaches have failed in large studies. This review focuses on basic research, pre-clinical and clinical findings that may account for the potential benefit of relaxin-2 in HFpEF. The peptide combines short-term hemodynamic advantages, such as moderate blood pressure decline and functional endothelin-1 antagonism, with a wealth of protective effects harboring long-term benefits, such as anti-inflammatory, anti-fibrotic, and anti-oxidative actions. These pleiotropic effects are exerted through a complex and intricate signaling cascade involving the relaxin-family peptide receptor-1, the glucocorticoid receptor, the nitric oxide system, and a cell type-dependent variety of down-stream mediators.

Cardioprotective actions of relaxin

Relaxin is a hormone of pregnancy first discovered for its ability to induce ligament relaxation in nonpregnant guinea pig and is important for softening of the birth canal during parturition, decidualization, implantation, nipple development and increased maternal renal perfusion, glomerular filtration, and cardiac output. Subsequently, relaxin has been shown to exert multiple beneficial cardiovascular effects during pathological events such as hypertension, atrial fibrillation, heart failure and myocardial infarction, including suppression of arrhythmia and inflammation, and reversal of fibrosis. Despite extensive studies, the mechanisms underlying relaxin's effects are not well understood. Relaxin signals primarily through its G protein coupled receptor, the relaxin family peptide receptor-1, to activate multiple signaling pathways and this review summarizes our understanding of these pathways as they relate to the cardioprotective actions of relaxin, focusing on relaxin's anti-fibrotic, anti-arrhythmic and anti-inflammatory properties. Further, this review includes a brief overview of relaxin in clinical trials for heart failure and progress in the development of relaxin mimetics.

Recent developments in relaxin mimetics as therapeutics for cardiovascular diseases

Cardiovascular disease is the most common cause of mortality worldwide, accounting for almost 50% of all deaths globally. Vascular endothelial dysfunction and fibrosis are critical in the pathophysiology of cardiovascular disease. Relaxin, an insulin-like peptide, is known to have beneficial actions in the cardiovascular system through its vasoprotective and anti-fibrotic effects. However, relaxin has several limitations of peptide-based drugs such as poor oral bioavailability, laborious, and expensive to synthesize. This review will focus on recent developments in relaxin mimetics, their pharmacology, associated signalling mechanisms, and their therapeutic potential for the management and treatment of cardiovascular disease.

Update on the management of acute heart failure

PURPOSE OF REVIEW

We provide a concise review of recent studies focusing on the management of patients with acute heart failure (AHF).

RECENT FINDINGS

In well designed randomized trials, no mortality benefit has been observed with the use of diuretics, ultrafiltration, inotropes and vasodilators in AHF. Recent trials examining the role of novel inotropes and vasodilators as well as the role of mineralocorticoid receptor antagonists in the AHF population, is reviewed.

SUMMARY

The focus of therapy in AHF should be directed towards symptom management. No mortality benefit has been observed despite good quality studies.

Clinical profiles in acute heart failure: an urgent need for a new approach

Acute heart failure (HF) is a major public health concern, responsible for >26 million hospitalizations per year worldwide. Many trials have investigated new therapeutic options for acute HF, with most revealing equivocal results. Successful innovations in therapy for acute HF have remained limited, and standard of care has remained largely unchanged over the past decade, suggesting the need for a new approach for therapeutic decision making and clinical trial design in acute HF. This manuscript focuses on one approach that could prove useful in the development and application of novel therapies: classification of patients based on clinical profiles. While previous attempts at developing clinical profiles were successful in stratifying patients based on clinical and laboratory variables, they have not been utilized for personalized treatment strategies that improve patient outcomes. We suggest a new approach to the creation of clinical profiles that could stratify patients based on their underlying aetiology and their response to novel interventions. We also investigate novel analytic approaches to the creation of new clinical profiles that both investigators and clinicians alike could utilize to inform clinical trial design and the application of new therapies. Despite a large number of clinical trials for new therapeutic options, the treatment of acute HF has seen few advances over the past decades. Innovative approaches to patient selection through the use of clinical profiles could help to identify patients most likely to benefit from novel interventions and lead to the discovery of new therapeutic options.

Acute heart failure

Acute heart failure (AHF) is one of the most common causes for hospital admission and is associated with a high risk of mortality. Compared to chronic heart failure, there is less robust evidence to guide diagnosis, risk stratification and management of AHF. This state-of-the art review aims to summarize new developments in this field. We also highlight areas of ongoing work including novel vasoactive agents, alternative models to traditional hospital admission and strategies to improve patient engagement.

Diuretic Resistance in Heart Failure

PURPOSE OF REVIEW

Diuretic resistance (DR) occurs along a spectrum of relative severity and contributes to worsening of acute heart failure (AHF) during an inpatient stay. This review gives an overview of mechanisms of DR with a focus on loop diuretics and summarizes the current literature regarding the prognostic value of diuretic efficiency and predictors of natriuretic response in AHF.

RECENT FINDINGS

The pharmacokinetics of diuretics are impaired in chronic heart failure, but little is known about mechanisms of DR in AHF. Almost all diuresis after administration of a loop diuretic dose occurs in the first few hours after administration and within-dose DR can develop. Recent studies suggest that DR at the level of the nephron may be more important than defects in diuretic delivery to the tubule. Because loop diuretics induce natriuresis, urine sodium (UNa) concentration may serve as a functional, physiological, and direct measure for diuretic responsiveness to a given loop diuretic dose. Identifying and targeting individuals with DR for more aggressive, tailored therapy represents an important opportunity to improve outcomes. A better understanding of the mechanistic underpinnings of DR in AHF is needed to identify additional biomarkers and guide future trials and therapies.

Early Treatment in Emergency Department Patients with Acute Heart Failure: Does Time Matter?

PURPOSE OF REVIEW

Acute heart failure accounts for over one million hospital discharges annually. Current guidelines suggest treatments for AHF should begin "without delay" but this time interval has not been clearly defined.

RECENT FINDINGS

Data suggest that certain treatments such as earlier treatment with diuretics and vasodilators may improve patient symptom relief, morbidity, and mortality. Secondary analyses of clinical trials of novel treatments under development have not shown similar results. The data are equivocal regarding the impact of early treatment in AHF on in-hospital and long-term morbidity and mortality. Improved clinical trial designs will help answer when and if "early" treatment should begin and whether it impacts short- and long-term outcomes in AHF.

Percutaneous periarticular multi-drug injection at one day after total knee arthroplasty as a component of multimodal pain management: a randomized control trial

Background

Although intraoperative periarticular multi-drug injection has been used for postoperative pain control after total knee arthroplasty (TKA), the injection has the inherent shortcoming of limited acting time. This randomized controlled trial was performed to assess whether adding percutaneous periarticular multi-drug injection at the day following TKA would improve the postoperative pain relief.

Methods

A total of 43 participants were randomly assigned to receive additional periarticular injection at 08:30, postoperative day 1 or no additional injection. The multi-drug solution including 40 mg of methylprednisolone, 150 mg of ropivacaine, and 0.1 mg of epinephrine was infiltrated into the muscle belly of the vastus medialis. In both groups, patients were treated with intraoperative periarticular multi-drug injection and postoperative intravenous and oral nonsteroidal anti-inflammatory drugs. We did not use any narcotic pain medications postoperatively. The primary outcome was the patients’ global assessment of postoperative pain at rest measured using a visual analog scale (VAS) and quantified as the area under the curve (AUC) of serial assessments until 20:00, postoperative day 5.

Results

The mean AUC for the postoperative pain VAS at rest was 1616 ± 1191 in patients received the additional periarticular injection versus 2808 ± 1494 in those received no injection (mean difference, − 1192; 95% confidence interval, − 2043 to − 340; p = 0.007). No wound complication or surgical site infection was observed in either groups.

Conclusions

Adding percutaneous periarticular multi-drug injection at the day following TKA may provide better postoperative pain relief. Further studies are needed to confirm the safety of the percutaneous injection.

Trial registration

University Hospital Medical Information Network UMIN000029003. Registered 5 September 2017.

Early and comprehensive care bundle in the elderly for acute heart failure in the emergency department: study protocol of the ELISABETH stepped-wedge cluster randomized trial

BACKGROUND

Acute heart failure (AHF) is one of the most common diagnoses for elderly patients in the emergency department (ED), with an admission rate above 80% and 1-month mortality around 10%. The European guidelines for the management of AHF are based on moderate levels of evidence, due to the lack of randomized controlled trials and the scarce evidence of any clinical added value of a specific treatment to improve outcomes. Recent reports suggest that the very early administration of full recommended therapy may decrease mortality. However, several studies have highlighted that elderly patients often received suboptimal treatment. Our hypothesis is that an early care bundle that comprises early and comprehensive management of symptoms, along with prompt detection and treatment of precipitating factors should improve AHF outcome in elderly patients.

METHODS/DESIGN

ELISABETH is a stepped-wedge, cluster randomized controlled, clinical trial in 15 emergency departments in France recruiting all patients aged 75 years and older with a diagnosis of AHF. The tested intervention is a care bundle with a checklist that mandates detection and early treatment of AHF precipitating factors, early and intensive treatment of congestion with intravenously administered nitrate boluses, and application of other recommended treatment (low-dose diuretics, non-invasive ventilation when indicated, and preventive low-molecular-weight heparin). Each center is randomized to the order in which they will switch from a "control period" to an "intervention period." All centers begin the trials with the control period for 2 weeks, then after each 2-week step a new center will enter the intervention period. At the end of the trial, all clusters will receive the intervention regimen. The primary outcome is the number of days alive and out of the hospital at 30 days.

DISCUSSION

If our hypothesis is confirmed, this trial will strengthen the level of evidence of AHF guidelines and stress the importance of the associated early and comprehensive treatment of precipitating factors. This trial could be the first to report a reduction in short-term morbidity and mortality in elderly AHF patients.

TRIAL REGISTRATION

ClinicalTrials.gov, ID: NCT03683212. Prospectively registered on 25 September 2018.

Peripartum cardiomyopathy

Peripartum cardiomyopathy (PPCM) is a rare, often dilated, cardiomyopathy with systolic dysfunction that presents in late pregnancy or, more commonly, the early postpartum period. Although the condition is prevalent worldwide, women with black ancestry seem to be at greatest risk, and the condition has a particularly high incidence in Nigeria and Haiti. Other risk factors include pre-eclampsia, advanced maternal age, and multiple gestation pregnancy. Although the complete pathophysiology of peripartum cardiomyopathy remains unclear, research over the past decade suggests the importance of vasculo-hormonal pathways in women with underlying susceptibility. At least some women with the condition harbor an underlying sarcomere gene mutation. More than half of affected women recover systolic function, although some are left with a chronic cardiomyopathy, and a minority requires mechanical support or cardiac transplantation (or both). Other potential complications include thromboembolism and arrhythmia. Currently, management entails standard treatments for heart failure with reduced ejection fraction, with attention to minimizing potential adverse effects on the fetus in women who are still pregnant. Bromocriptine is one potential disease specific treatment under investigation. In this review, we summarize the current literature on peripartum cardiomyopathy, as well as gaps in the understanding of this condition and future research directions.

New therapies for the treatment of heart failure: a summary of recent accomplishments

Despite continuous efforts to prevent cardiovascular diseases (CVDs), heart failure prevails as the number one cause of death in developed countries. To properly treat CVDs, scientists had to take a closer look at the factors that contribute to their pathogenesis and either modernize current pharmaceuticals or develop brand new treatments. Enhancement of current drugs, such as tolvaptan and omecamtiv mecarbil, sheds new light on already-known therapies. Tolvaptan, a vasopressin antagonist, could be adopted in heart failure therapy as it reduces pre- and afterload by decreasing systolic blood pressure and blood volume. Omecamtiv mecarbil, which is a myosin binding peptide, could aid cardiac contractility. The next generation vasodilators, serelaxin and ularitide, are based on naturally occurring peptides and they reduce peripheral vascular resistance and increase the cardiac index. In combination with their anti-inflammatory properties, they could turn out to be extremely potent drugs for heart failure treatment. Cardiotrophin has exceeded many researchers’ expectations, as evidence suggests that it could cause sarcomere hypertrophy without excessive proliferation of connective tissue. Rapid progress in gene therapy has caused it to finally be considered as one of the viable options for the treatment of CVDs. This novel therapeutic approach could restore stable heart function either by restoring depleted membrane proteins or by balancing the intracellular calcium concentration. Although it has been set back by problems concerning its long-term effects, it is still highly likely to succeed.

Evolving Landscape of Clinical Trials in Heart Failure: Patient Populations, Endpoint Selection, and Regions of Enrollment

PURPOSE OF REVIEW

Clinical trial design and execution are evolving as increasingly important considerations with respect to the success of heart failure trials. The current review highlights temporal trends in characteristics of heart failure clinical trials.

RECENT FINDINGS

Recent trials in heart failure have required longer recruitment phases, displayed inefficient enrollment rates, increased use of composite and nonfatal endpoints, undergone rapid globalization, and gradually increased focus on heart failure with preserved ejection fraction. Understanding patterns and trends in clinical trial design and execution may inform future planning and conduct of trials of heart failure therapeutics.

Spironolactone inhibits endothelial-mesenchymal transition via the adenosine A2A receptor to reduce cardiorenal fibrosis in rats

AIMS

The mechanisms underlying cardiorenal syndromes are complex and not fully understood; Fibrosis seems to be a primary driver of the diseases' pathophysiology. Spironolactone can reduce cardiac or renal fibrosis by inhibiting endothelial-mesenchymal transition (EndMT). Spironolactone protection may rely on activation of adenosine receptors, but the role of the adenosine A2A receptor (A2AR) is unclear. We hypothesize that spironolactone may modulate A2AR to suppress EndMT and reduce cardiorenal remodeling.

MAIN METHODS

A model of renal injury followed by heart failure was established by subcutaneous administration of isoprenaline (Iso) to rats. Assessment of cardiac and renal function, fibrosis, EndMT markers, adenosine and A2AR expression was performed. TGF-β was used to induce EndMT in primary human umbilical vein endothelial cells (HUVECs). Rats or cells were divided into four groups: those that treated with spironolactone alone or in combination with A2AR antagonist ZM241385 or neither, and compared to normal controls.

KEY FINDINGS

Isoprenaline-treated rats exhibited cardiac and renal fibrosis, impaired cardiac and renal function, enhanced EndMT, and lower A2AR expression. Spironolactone significantly up-regulated A2AR expression and inhibited EndMT in vivo and in vitro. Moreover, spironolactone improved cardiorenal remodeling and reduced dysfunction. These changes were exacerbated by administration of ZM241385. Together, these findings show that spironolactone up-regulated A2AR to reduce EndMT and ameliorate cardiorenal fibrosis.

SIGNIFICANCE

The anti-fibrotic effects of spironolactone may partly depend on the up-regulation of A2AR, and that A2AR might be a potential therapeutic target for the treatment of cardiorenal syndrome.

Efficacy and safety of serelaxin when added to standard of care in patients with acute heart failure: results from a PROBE study, RELAX-AHF-EU

AIM

Serelaxin is a recombinant human relaxin-2 hormone, which confers receptor-mediated vasodilatation in a tissue-specific fashion. The RELAX-AHF-EU study assessed the effect of serelaxin when added to standard-of-care (SoC) therapy on worsening heart failure (WHF)/all-cause death through Day 5 in patients hospitalised for acute heart failure (AHF) in Europe.

METHODS AND RESULTS

This multicentre, prospective, randomised, open-label, blinded-endpoint validation study enrolled hospitalised AHF patients and randomised (2:1) eligible patients (mild-to-moderate renal impairment and systolic blood pressure ≥ 125 mmHg) within 16 h of presentation with signs/symptoms of AHF, to receive 48 h intravenous infusion of 30 μg/kg/day serelaxin + SoC or SoC alone. The primary endpoint was adjudicated WHF/all-cause death through Day 5. Of 3183 patients targeted, 2666 were randomised when the study was terminated early by the sponsor due to the neutral results of the pivotal RELAX-AHF-2 study. Adjudicated WHF/all-cause death through Day 5 was significantly reduced in the serelaxin + SoC vs. SoC group (5.0% vs. 6.9%; hazard ratio 0.71; 95% confidence interval 0.51-0.98; P = 0.0172) (absolute risk reduction 1.9%, number needed to treat 53). The difference between treatment groups was not significant for WHF/all-cause death/heart failure rehospitalisation through Day 14 and length of hospital stay. A significantly smaller proportion of patients in the serelaxin + SoC vs. SoC group experienced persistent heart failure signs/symptoms at each visit until Day 4, or renal deterioration through Day 5 (all P ≤ 0.01). Overall incidence of treatment-emergent adverse events was comparable between treatment groups. Hypotension and decrease in haemoglobin/haematocrit were more frequent in the serelaxin + SoC group.

CONCLUSION

When added to SoC, serelaxin reduced adjudicated WHF or all-cause death through Day 5 in AHF patients. The results from this open-label study should be considered in the context of the totality of the double-blind, randomised evidence on serelaxin in AHF.

KSHF Guidelines for the Management of Acute Heart Failure: Part II. Treatment of Acute Heart Failure

The prevalence of heart failure (HF) is on the rise due to the aging of society. Furthermore, the continuous progress and widespread adoption of screening and diagnostic strategies have led to an increase in the detection rate of HF, effectively increasing the number of patients requiring monitoring and treatment. Because HF is associated with substantial rates of mortality and morbidity, as well as high socioeconomic burden, there is an increasing need for developing specific guidelines for HF management. The Korean guidelines for the diagnosis and management of chronic HF were introduced in March 2016. However, chronic and acute HF represent distinct disease entities. Here, we introduce the Korean guidelines for the management of acute HF with reduced or preserved ejection fraction. Part II of this guideline covers the treatment of acute HF.

Update on heart failure management and future directions

Heart failure (HF) is an important cardiovascular disease because of its increasing prevalence, significant morbidity, high mortality, and rapidly expanding health care cost. The number of HF patients is increasing worldwide, and Korea is no exception. There have been marked advances in definition, diagnostic modalities, and treatment of HF over the past four decades. There is continuing effort to improve risk stratification of HF using biomarkers, imaging and genetic testing. Newly developed medications and devices for HF have been widely adopted in clinical practice. Furthermore, definitive treatment for end-stage heart failure including left ventricular assist device and heart transplantation are rapidly evolving as well. This review summarizes the current state-of-the-art management for HF and the emerging diagnostic and therapeutic modalities to improve the outcome of HF patients.

Effect of the peptides Relaxin, Neuregulin, Ghrelin and Glucagon-like peptide-1, on cardiomyocyte factors involved in the molecular mechanisms leading to diastolic dysfunction and/or heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction (HFpEF) represents an important cardiac condition because of its increasing prevalence, resistance to treatment and high associated morbidity and mortality. Two of the major mechanisms responsible for HFpEF are impaired cardiomyocyte sarcoplasmic reticulum (SR) Ca²⁺ ATPase (SERCA2a), which is responsible for calcium reuptake into the SR, and cardiac fibroblasts/myofibroblasts that produce collagen or myocardial fibrosis. Phospholamban (PLB), in the SR and endoplasmic reticulum, is the primary regulator of SERCA2a in the heart and acts as a reversible inhibitor of SERCA2a. Glucagon-like peptide-1, a 30 amino acid peptide, improves diastolic function through increasing SERCA2a expression and activity as well as by decreasing phosphorylation of Ryanodine receptors. It also enhances collagen production through enhanced procollagen IalphaI/IIIalphaI, connective tissue growth factor, fibronectin, TGF-β3 as well as Interleukin -10, -1beta, and -6 gene expression. Relaxin-2, a two chain, 53 amino acid peptide, increases Ser16- and Thr17-phosphorylation levels of PLB, thereby relieving SERCA2a of its inhibition. H3 Relaxin inhibits TGF-β1-stimulated collagen deposition through H3 relaxin-induced increases in pSmad2. Neuregulin-1, an epidermal growth factor, induces nitric oxide and PI-3 kinase activation that enhance SERCA2 activity. Neuregulin-1 was associated with less myocardial macrophage infiltration and cytokine expression reducing collagen deposition. Ghrelin, a 28 amino acid peptide, improves SERCA2a function by inducing PLB phosphorylation. Ghrelin also reduces cardiac fibrosis. In summary, Glucagon-like peptide-1, Relaxin-2, Neuregulin-1, and Ghrelin each modify calcium dynamics, collagen expression, and myocardial fibrosis through attenuation of deleterious signaling cascades, and induction of adaptive pathways, representing potential therapeutic targets for HFpEF.

Multi-Component Mechanism of H2 Relaxin Binding to RXFP1 through NanoBRET Kinetic Analysis

The peptide hormone H2 relaxin has demonstrated promise as a therapeutic, but mimetic development has been hindered by the poorly understood relaxin receptor RXFP1 activation mechanism. H2 relaxin is hypothesized to bind to two distinct ECD sites, which reorientates the N-terminal LDLa module to activate the transmembrane domain. Here we provide evidence for this model in live cells by measuring bioluminescence resonance energy transfer (BRET) between nanoluciferase-tagged RXFP1 constructs and fluorescently labeled H2 relaxin (NanoBRET). Additionally, we validate these results using the related RXFP2 receptor and chimeras with an inserted RXFP1-binding domain utilizing NanoBRET and nuclear magnetic resonance studies on recombinant proteins. We therefore provide evidence for the multi-component molecular mechanism of H2 relaxin binding to RXFP1 on the full-length receptor in cells. Also, we show the utility of NanoBRET real-time binding kinetics to reveal subtle binding complexities, which may be overlooked in traditional equilibrium binding assays.

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NanoBRET was used to assess relaxin binding kinetics to its receptor RXFP1

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Binding on wild-type and mutant RXFP1 demonstrated a multi-component mechanism

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This binding mode was validated using RXFP2/RXFP1 chimeras and protein NMR studies

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NanoBRET binding can reveal subtle GPCR binding modes to aid drug development

Impact of admission liver stiffness on long-term clinical outcomes in patients with acute decompensated heart failure

Liver stiffness (LS) has been reported to be a marker of liver congestion caused by elevated central venous pressure in heart failure (HF) patients. Recent studies demonstrated that LS could be non-invasively measured by virtual touch quantification (VTQ). However, its prognostic implication in patients with acute decompensated heart failure (ADHF) is unclear. This study sought to determine whether LS measured by VTQ could be a determinant of subsequent adverse events in ADHF patients. We prospectively recruited 70 ADHF patients who underwent LS measurement by VTQ on admission in our university hospital between June 2016 and April 2018. The primary outcome of interest was the composite of all-cause mortality and worsening HF. During a median follow-up period of 272 (interquartile range 122-578) days, there were 26 (37%) events, including 5 (7%) deaths and 21 (30%) cases of worsening HF. The c-index of LS for predicting the composite of adverse events was 0.77 (95% CI 0.66-0.88), and the optimal cut-off value of LS was 1.50 m/s. Adverse events were more frequently observed in patients with high LS (≥ 1.50 m/s) compared to those with low LS (< 1.50 m/s). Multivariable Cox regression analyzes revealed that higher LS was independently associated with increased subsequent risk of adverse events after adjustment for confounders. In conclusion, high admission LS was an independent determinant of worse clinical outcomes in patients with ADHF. This finding suggests that LS on admission is useful for risk stratification of patients with ADHF.

Practical management of concomitant acute heart failure and worsening renal function in the emergency department

Worsening renal function (i.e. any increase in creatinine or decrease in the estimated glomerular filtration rate) is common in patients admitted for acute heart failure in the emergency department. Although worsening renal function (WRF) has been associated with the occurrence of dismal outcomes, this only appears to be the case when associated with clinical deterioration. However, if the clinical status of the patient is improving, a certain increase in serum creatinine may be acceptable. This WRF, which is not associated with clinical deterioration or adverse outcomes (e.g. during treatment up-titration), has been referred to as 'pseudo-WRF' and should not detract clinicians from targeting 'guideline-recommended' therapies. This is an important message for emergency physicians to pursue diuretics as long as signs of pulmonary congestion persist to improve the clinical status of the patient. In the present review, we aim to provide clinicians in acute settings with an integrative and comprehensive approach to cardiorenal interactions in acute heart failure.