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

Engineering a long acting, non-biased relaxin agonist using Protein-in-Protein technology

The peptide hormone relaxin plays a critical role in tissue remodeling in a variety of tissues through activation of its cognate receptor, RXFP1. Relaxin's ability to modify extracellular matrices has provided a strong rationale for treating fibrosis in a variety of tissues. Treatment with recombinant relaxin peptides in clinical studies of heart failure has not yet proven useful, likely due to the short half-life of infused peptide. To circumvent this particular pharmacokinetic pitfall we have used a Protein-in-Protein (PiP) antibody technology described previously, to insert a single-chain human relaxin construct into the complementarity-determining region (CDR) of an immunoglobulin G (IgG) backbone, creating a relaxin molecule with a half-life of ∼4-5 days in mice. Relaxin-PiP biologics displaced Europium-labeled human relaxin in RXFP1-expressing cells and demonstrated full agonist activity on both human and mouse RXFP1 receptors. Relaxin-PiPs did not show signal transduction bias, as they activated cAMP in THP-1 cells, and cGMP and pERK signaling in primary human cardiac fibroblasts. In an induced carbon tetrachloride mouse model of liver fibrosis one relaxin-PiP, R2-PiP, caused reduction of liver lesions, ameliorated collagen accumulation in the liver with the corresponding reduction of Collagen1a1 gene expression, and increased cell proliferation in hepatic parenchyma. These relaxin biologics represent a novel approach to the design of a long-acting RXFP1 agonist to probe the clinical utility of relaxin/RXFP1 signaling to treat a variety of human fibrotic diseases.

Therapeutic potential of relaxin or relaxin mimetics in managing cardiovascular complications of diabetes

Diabetes mellitus is a metabolic disease with an escalating global prevalence. Despite the abundance and relative efficacies of current therapeutic approaches, they primarily focus on attaining the intended glycaemic targets, but patients ultimately still suffer from various diabetes-associated complications such as retinopathy, nephropathy, cardiomyopathy, and atherosclerosis. There is a need to explore innovative and effective diabetic treatment strategies that not only address the condition itself but also combat its complications. One promising option is the reproductive hormone relaxin, an endogenous ligand of the RXFP1 receptor. Relaxin is known to exert beneficial actions on the cardiovascular system through its vasoprotective, anti-inflammatory and anti-fibrotic effects. Nevertheless, the native relaxin peptide exhibits a short biological half-life, limiting its therapeutic potential. Recently, several relaxin mimetics and innovative delivery technologies have been developed to extend its biological half-life and efficacy. The current review provides a comprehensive landscape of the cardiovascular effects of relaxin, focusing on its potential therapeutic applications in managing complications associated with diabetes. The latest advancements in the development of relaxin mimetics and delivery methods for the treatment of cardiometabolic disorders are also discussed.

Novel Relaxin Receptor RXFP1 Agonist AZD3427 in the Treatment of Heart Failure: A Phase 1a/b, First-in-Human, Randomized, Single-Blind, Placebo-Controlled Study

BACKGROUND

Heart failure mortality remains high despite recent progress in pharmacological treatment. AZD3427 is a selective long-acting analog of relaxin, a vasodilatory hormone with antifibrotic effects. We assessed the safety, pharmacokinetics, and pharmacodynamics of AZD3427 in healthy volunteers and patients with heart failure on standard-of-care therapy.

METHODS AND RESULTS

In this first-in-human, phase 1a/b, randomized, single-blind, placebo-controlled study, healthy volunteers were randomized 6:2 to receive a single dose of AZD3427 or placebo by subcutaneous injection in 5 mixed-ethnicity cohorts (5, 10, 30, 90, or 270 mg) and 1 Japanese-descent cohort (270 mg), or by intravenous injection in 1 cohort (15 mg). After confirming safety and tolerability in healthy volunteers, 3 cohorts of patients with heart failure and left ventricular ejection fraction ≤40% and 3 cohorts with ejection fraction ≥41% were randomized 6:2 to receive 5 weekly doses of AZD3427 (5, 15, or 45 mg) or placebo by subcutaneous injection. In total, 56 healthy volunteers and 48 patients with heart failure were randomized. AZD3427 was well tolerated at all doses. After subcutaneous administration, AZD3427 was absorbed slowly, and exposure was approximately linear across the dose range. In patients with heart failure, AZD3427 terminal half-life was 13 to 14 days and there were numerical increases in stroke volume and estimated glomerular filtration rate. No treatment-emergent antidrug antibodies were detected.

CONCLUSIONS

AZD3427 had favorable safety and pharmacokinetic profiles. Hemodynamic changes in patients with heart failure were consistent with the anticipated effects of a relaxin analog. These findings support further development of AZD3427 as a novel long-term treatment for patients with heart failure.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique Identifier: NCT04630067.

Cardiovascular effects of relaxin-2: therapeutic potential and future perspectives

The hormone relaxin-2 has emerged as a promising player in regulating the physiology of the cardiovascular system. Through binding to the relaxin family peptide receptor 1 (RXFP1), this hormone elicits multiple physiological responses including vasodilation induction, reduction of inflammation and oxidative stress, and angiogenesis stimulation. The role of relaxin-2, or its recombinant human form known as serelaxin, has been investigated in preclinical and clinical studies as a potential therapy for cardiovascular diseases, especially heart failure, whose current therapy is still unoptimized. However, evidence from past clinical trials has been inconsistent and further research is needed to fully understand the potential applications of relaxin-2. This review provides an overview of serelaxin use in clinical trials and discusses future directions in the development of relaxin-2 mimetics, which may offer new therapeutic options for patients with heart failure.

Translational pharmacokinetic/pharmacodynamic model for mRNA-0184, an investigational therapeutic for the treatment of heart failure

Heart failure (HF) is a complex, progressive disorder that is associated with substantial morbidity and mortality on a global scale. Relaxin-2 is a naturally occurring hormone that may have potential therapeutic benefit for patients with HF. To investigate the therapeutic potential of relaxin in the treatment of patients with HF, mRNA-0184, a novel, investigational, lipid nanoparticle (LNP)-encapsulated mRNA therapy that encodes for human relaxin-2 fused to variable light chain kappa (Rel2-vlk) was developed. A translational semi-mechanistic population pharmacokinetic (PK)/pharmacodynamic (PD) model was developed using data from non-human primates at dose levels ranging from 0.15 to 1 mg/kg. The PK/PD model was able to describe the PK of Rel2-vlk mRNA and translated Rel2-vlk protein in non-human primates adequately with relatively precise estimates. The preclinical PK/PD model was then scaled allometrically to determine the human mRNA-0184 dose that would achieve therapeutic levels of Rel2-vlk protein expression in patients with stable HF with reduced ejection fraction. Model-based simulations derived from the scaled PK/PD model support the selection of 0.025 mg/kg as an appropriate starting human dose of mRNA-0184 to achieve average trough relaxin levels between 1 and 2.5 ng/mL, which is the potential exposure for cardioprotective action of relaxin.

Sex-Based Differences in the Epidemiology, Clinical Characteristics, and Outcomes Associated with Worsening Heart Failure Events in a Learning Health System

BACKGROUND

Differences in demographics, risk factors, and clinical characteristics may contribute to variations in men and women in terms of the prevalence, clinical setting, and outcomes associated with worsening heart failure (WHF) events. We sought to describe sex-based differences in the epidemiology, clinical characteristics, and outcomes associated with WHF events across clinical settings.

METHODS AND RESULTS

We examined adults diagnosed with HF from 2010 to 2019 within a large, integrated health care delivery system. Electronic health record data were accessed for hospitalizations, emergency department (ED) visits and observation stays, and outpatient encounters. WHF was identified using validated natural language processing algorithms and defined as ≥1 symptom, ≥2 objective findings (including ≥1 sign), and ≥1 change in HF-related therapy. Incidence rates and associated outcomes for WHF were compared across care setting by sex. We identified 1,122,368 unique clinical encounters with a diagnosis code for HF, with 124,479 meeting WHF criteria. These WHF encounters existed among 102,116 patients, of whom 48,543 (47.5%) were women and 53,573 (52.5%) were men. Women experiencing WHF were older and more likely to have HF with preserved ejection fraction compared with men. The clinical settings of WHF were similar among women and men: hospitalizations (36.8% vs 37.7%), ED visits or observation stays (11.8% vs 13.4%), and outpatient encounters (4.4% vs 4.9%). Women had lower odds of 30-day mortality after an index hospitalization (adjusted odds ratio 0.88, 95% confidence interval 0.83-0.93) or ED visit or observation stay (adjusted odds ratio 0.86, 95% confidence interval 0.75-0.98) for WHF.

CONCLUSIONS

Women and men contribute similarly to WHF events across diverse clinical settings despite marked differences in age and left ventricular ejection fraction.

A Review of Contemporary and Future Pharmacotherapy for Chronic Heart Failure in Children

This review delves into the most recent therapeutic approaches for pediatric chronic heart failure (HF) as proposed by the International Society for Heart and Lung Transplantation (ISHLT), which are not yet publicly available. The guideline proposes an exhaustive overview of the evolving pharmacological strategies that are transforming the management of HF in the pediatric population. The ISHLT guidelines recognize the scarcity of randomized clinical trials in children, leading to a predominance of consensus-based recommendations, designated as Level C evidence. This review article aims to shed light on the significant paradigm shifts in the proposed 2024 ISHLT guidelines for pediatric HF and their clinical ramifications for pediatric cardiology practitioners. Noteworthy advancements in the updated proposed guidelines include the endorsement of angiotensin receptor-neprilysin inhibitors (ARNIs), sodium-glucose cotransporter 2 inhibitors (SGLT2is), and soluble guanylate cyclase (sGC) stimulators for treating chronic HF with reduced ejection fraction (HFrEF) in children. These cutting-edge treatments show potential for enhancing outcomes in pediatric HFrEF. Nonetheless, the challenge persists in validating the efficacy of therapies proven in adult HFrEF for the pediatric cohort. Furthermore, the proposed ISHLT guidelines address the pharmacological management of chronic HF with preserved ejection fraction (HFpEF) in children, marking a significant step forward in pediatric HF care. This review also discusses the future HF drugs in the pipeline, their mechanism of actions, potential uses, and side effects.

Prognostic association of circulating relaxin-2 in acute heart failure

BACKGROUND

Despite the increasing interest in the study of the endogenous relaxin system in heart failure (HF), its role as a prognostic marker in acute HF remains unclear. We aimed to evaluate the association of relaxin-2 circulating levels with 6 months' mortality in acute HF.

METHODS

We evaluated relaxin-2 serum levels at admission in a cohort of patients with acute HF (n = 202) using an enzyme immunoassay. The ability of relaxin-2 to predict all-cause death (primary outcome) and HF-specific death (secondary outcome) at 6 months was assessed using Cox-regression analysis.

RESULTS

The median age was 79 (70-85) years old, 44% of the patients were male, and 43% had preserved ejection fraction (≥50%). Median serum relaxin-2 level was 25 pg/mL. Patients with higher relaxin-2 levels had more peripheral oedemas, higher sodium retention score, higher pulmonary artery pressures, higher prevalence of right ventricle dysfunction and lower inferior vena cava collapse at inspiration. Conversely, there was no association with left chambers parameters or with B-type natriuretic peptide (BNP). Higher relaxin-2 concentrations were associated with a higher risk of all-cause death [HR 1.15; 95%CI 1.01,1.30; P = 0.030] and HF-specific death [HR 1.21; 95% CI 1.03-1.42; P = 0.018], after adjustment for classical prognostic factors such as age, sex and BNP.

CONCLUSIONS

In our acute HF population, relaxin-2 circulating levels were associated with clinical and echocardiographic markers of systemic congestion and with 6-months' mortality, independently of BNP. These results lay the groundwork for future investigations on the potential of relaxin-2 as an auxiliary biomarker in HF.

Targeting G protein-coupled receptors for heart failure treatment

Heart failure remains a leading cause of morbidity and mortality worldwide. Current treatment for patients with heart failure include drugs targeting G protein-coupled receptors such as β-adrenoceptor antagonists (β-blockers) and angiotensin II type 1 receptor antagonists (or angiotensin II receptor blockers). However, many patients progress to advanced heart failure with persistent symptoms, despite treatment with available therapeutics that have been shown to reduce mortality and mortality. GPCR targets currently being explored for the development of novel heart failure therapeutics include adenosine receptor, formyl peptide receptor, relaxin/insulin-like family peptide receptor, vasopressin receptor, endothelin receptor and the glucagon-like peptide 1 receptor. Many GPCR drug candidates are limited by insufficient efficacy and/or dose-limiting unwanted effects. Understanding the current challenges hindering successful clinical translation and the potential to overcome existing limitations will facilitate the future development of novel heart failure therapeutics. LINKED ARTICLES: This article is part of a themed issue Therapeutic Targeting of G Protein-Coupled Receptors: hot topics from the Australasian Society of Clinical and Experimental Pharmacologists and Toxicologists 2021 Virtual Annual Scientific Meeting. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v181.14/issuetoc.

Relaxin as a treatment for musculoskeletal fibrosis: What we know and future directions

Fibrotic changes in musculoskeletal diseases arise from the abnormal buildup of fibrotic tissue around the joints, leading to limited mobility, compromised joint function, and diminished quality of life. Relaxin (RLX) attenuates fibrosis by accelerating collagen degradation and inhibiting excessive extracellular matrix (ECM) production. Further, RLX disrupts myofibroblast activation by modulating the TGF-β/Smads signaling pathways, which reduces connective tissue fibrosis. However, the mechanisms and effects of RLX in musculoskeletal pathologies are emerging as increasing research focuses on relaxin's impact on skin, ligaments, tendons, cartilage, joint capsules, connective tissues, and muscles. This review delineates the actions of relaxin within the musculoskeletal system and the challenges to its clinical application. Relaxin shows significant potential in both in vivo and in vitro studies for broadly managing musculoskeletal fibrosis; however, challenges such as short biological half-life and sex-specific responses may pose hurdles for clinical use.

Functional crosstalk between angiotensin receptors (types 1 and 2) and relaxin family peptide receptor 1 (RXFP1): Implications for the therapeutic targeting of fibrosis

Class A, rhodopsin-like, G-protein-coupled receptors (GPCRs) are by far the largest class of GPCRs and are integral membrane proteins used by various cells to convert extracellular signals into intracellular responses. Initially, class A GPCRs were believed to function as monomers, but a growing body of evidence has emerged to suggest that these receptors can function as homodimers and heterodimers and can undergo functional crosstalk to influence the actions of agonists or antagonists acting at each receptor. This review will focus on the angiotensin type 1 (AT1) and type 2 (AT2) receptors, as well as the relaxin family peptide receptor 1 (RXFP1), each of which have their unique characteristics but have been demonstrated to undergo some level of interaction when appropriately co-expressed, which influences the function of each receptor. In particular, this receptor functional crosstalk will be discussed in the context of fibrosis, the tissue scarring that results from a failed wound-healing response to injury, and which is a hallmark of chronic disease and related organ dysfunction. LINKED ARTICLES: This article is part of a themed issue Therapeutic Targeting of G Protein-Coupled Receptors: hot topics from the Australasian Society of Clinical and Experimental Pharmacologists and Toxicologists 2021 Virtual Annual Scientific Meeting. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v181.14/issuetoc.

Cardiomyocyte-specific RXFP1 overexpression protects against pressure overload-induced cardiac dysfunction independently of relaxin

Heart failure (HF) prevalence is rising due to reduced early mortality and demographic change. Relaxin (RLN) mediates protective effects in the cardiovascular system through Relaxin-receptor 1 (RXFP1). Cardiac overexpression of RXFP1 with additional RLN supplementation attenuated HF in the pressure-overload transverse aortic constriction (TAC) model. Here, we hypothesized that robust transgenic RXFP1 overexpression in cardiomyocytes (CM) protects from TAC-induced HF even in the absence of RLN. Hence, transgenic mice with a CM-specific overexpression of human RXFP1 (hRXFP1tg) were generated. Receptor functionality was demonstrated by in vivo hemodynamics, where the administration of RLN induced positive inotropy strictly in hRXFP1tg. An increase in phospholamban-phosphorylation at serine 16 was identified as a molecular correlate. hRXFP1tg were protected from TAC without additional RLN administration, presenting not only less decline in systolic left ventricular (LV) function but also abrogated LV dilation and pulmonary congestion compared to WT mice. Molecularly, transgenic hearts exhibited not only a significantly attenuated fetal and fibrotic gene activation but also demonstrated less fibrotic tissue and CM hypertrophy in histological sections. These protective effects were evident in both sexes. Similar cardioprotective effects of hRXFP1tg were detectable in a RLN-knockout model, suggesting an alternative mechanism of receptor activation through intrinsic activity, alternative endogenous ligands or crosstalk with other receptors. In summary, CM-specific RXFP1 overexpression provides protection against TAC even in the absence of endogenous RLN. This suggests RXFP1 overexpression as a potential therapeutic approach for HF, offering baseline protection with optional RLN supplementation for specific activation.

Vasodilators for Acute Heart Failure - A Systematic Review with Meta-Analysis

BACKGROUND

Acute heart failure is a public health concern. This study systematically reviewed randomized clinical trials (RCTs) to evaluate vasodilators in acute heart failure.

METHODS

The search was conducted across the databases of Medline, Embase, Latin American and the Caribbean Literature on Health Sciences, Web of Science, and the Cochrane Central Register of Controlled Trials. Inclusion criteria consisted of RCTs that compared vasodilators versus standard care, placebo, or cointerventions. The primary outcome was all-cause mortality; secondary outcomes were serious adverse events (SAEs), tracheal intubation, and length of hospital stay. Risk of bias was assessed in all trials.

RESULTS

The study included 46 RCTs that enrolled 28,374 patients with acute heart failure. Vasodilators did not reduce the risk of all-cause mortality (risk ratio, 0.95; 95% confidence interval [CI], 0.87 to 1.04; I2=9.51%; P=0.26). No evidence of a difference was seen in the risk of SAEs (risk ratio, 1.01; 95% CI, 0.97 to 1.05; I2=0.94%) or length of hospital stay (mean difference, -0.10; 95% CI, -0.28 to 0.08; I2=69.84%). Vasodilator use was associated with a lower risk of tracheal intubation (risk ratio, 0.54; 95% CI, 0.30 to 0.99; I2=51.96%) compared with no receipt of vasodilators.

CONCLUSIONS

In this systematic review with meta-analysis of patients with acute heart failure, vasodilators did not reduce all-cause mortality.

The involvement of the Wnt/β-catenin signaling cascade in fibrosis progression and its therapeutic targeting by relaxin

Organ scarring, referred to as fibrosis, results from a failed wound-healing response to chronic tissue injury and is characterised by the aberrant accumulation of various extracellular matrix (ECM) components. Once established, fibrosis is recognised as a hallmark of stiffened and dysfunctional tissues, hence, various fibrosis-related diseases collectively contribute to high morbidity and mortality in developed countries. Despite this, these diseases are ineffectively treated by currently-available medications. The pro-fibrotic cytokine, transforming growth factor (TGF)-β1, has emerged as the master regulator of fibrosis progression, owing to its ability to promote various factors and processes that facilitate rapid ECM synthesis and deposition, whilst negating ECM degradation. TGF-β1 signal transduction is tightly controlled by canonical (Smad-dependent) and non-canonical (MAP kinase- and Rho-associated protein kinase-dependent) intracellular protein activity, whereas its pro-fibrotic actions can also be facilitated by the Wnt/β-catenin pathway. This review outlines the pathological sequence of events and contributing roles of TGF-β1 in the progression of fibrosis, and how the Wnt/β-catenin pathway contributes to tissue repair in acute disease settings, but to fibrosis and related tissue dysfunction in synergy with TGF-β1 in chronic diseases. It also outlines the anti-fibrotic and related signal transduction mechanisms of the hormone, relaxin, that are mediated via its negative modulation of TGF-β1 and Wnt/β-catenin signaling, but through the promotion of Wnt/β-catenin activity in acute disease settings. Collectively, this highlights that the crosstalk between TGF-β1 signal transduction and the Wnt/β-catenin cascade may provide a therapeutic target that can be exploited to broadly treat and reverse established fibrosis.

Periodic injections of Relaxin 2, its pharmacokinetics and remodeling of rat hearts

Relaxin-2 (RLX), a critical hormone in pregnancy, has been investigated as a therapy for heart failure. In most studies, the peptide was delivered continuously, subcutaneously for 2 weeks in animals or intravenously for 2-days in human subjects, for stable circulating [RLX]. However, pulsatile hormone levels may better uncover the normal physiology. This premise was tested by subcutaneously injecting Sprague Dawley rats (250 g, N = 2 males, 2 females/group) with human RLX (0, 30, 100, or 500 µg/kg), every 12 h for 1 day, then measuring changes in Nav1.5, connexin43, and β-catenin, 24 h later. Pulsatile RLX was measured by taking serial blood draws, post-injection. After an injection, RLX reached a peak in ∼ 60 min, fell to 50 % in 5-6 h; injections of 0, 30, 100 or 500 µg/kg yielded peak levels of 0, 11.26 ± 3.52, 58.33 ± 16.10, and 209.42 ± 29.04 ng/ml and residual levels after 24-hrs of 0, 4.9, 45.1 and 156 pg/ml, respectively. The 30 µg/kg injections had no effect and 100 µg/kg injections increased Nav1.5 (25 %), Cx43 (30 %) and β-catenin (90 %). The 500 µg/kg injections also increased Nav1.5 and Cx43 but were less effective at upregulating β-catenin (up by 25 % vs. 90 %). Periodic injections of 100 µg/kg were highly effective at increasing the expression of Nav1.5 and Cx43 which are key determinants of conduction velocity in the heart and the suppression of arrhythmias. Periodic RLX is effective at eliciting changes in cardiac protein expression and may be a better strategy for its longer-term delivery in the clinical setting.

Significance of plasma relaxin-2 levels in patients with primary hypertension and type 2 diabetes mellitus

BACKGROUND

This study aimed to evaluate plasma relaxin‑2 (RLN-2) levels in patients with arterial hypertension (AH) and their relationships with clinical and laboratory parameters.

METHODS

The study involved 106 hypertensive patients, including 55 with type 2 diabetes mellitus (T2DM), and 30 control subjects. Plasma RLN-2 levels were measured using an enzyme-linked immunosorbent assay kit.

RESULTS

RLN-2 levels were reduced in patients with AH compared to healthy volunteers (p < 0.001), and hypertensive patients with T2DM had lower RLN-2 levels than those without impaired glucose metabolism (p < 0.001). RLN‑2 was negatively correlated with systolic blood pressure (SBP) (p < 0.001) and anthropometric parameters such as body mass index (BMI; p = 0.027), neck (p = 0.045) and waist (p = 0.003) circumferences, and waist-to-hip ratio (p = 0.011). RLN‑2 also had inverse associations with uric acid levels (p = 0.019) and lipid profile parameters, particularly triglycerides (p < 0.001) and non-HDL-C/HDL‑C (p < 0.001), and a positive relationship with HDL‑C (p < 0.001). RLN‑2 was negatively associated with glucose (p < 0.001), insulin (p = 0.043), HbA1c (p < 0.001), and HOMA-IR index (p < 0.001). Univariate binary logistic regression identified RLN‑2 as a significant predictor of impaired glucose metabolism (p < 0.001).

CONCLUSIONS

Decreased RLN-2 levels in patients with AH and T2DM and established relationships of RLN‑2 with SBP and parameters of glucose metabolism and lipid profile suggest a diagnostic role of RLN‑2 as a biomarker for AH with T2DM.

New Pharmacotherapeutic Classes for the Management of Heart Failure: A Narrative Review

Heart failure (HF) is a syndrome characterized by the heart failing to pump blood to the body at a rate proportional to its needs. HF is a public health burden globally and one of the leading causes of hospitalizations in adults. While many classes of drugs have been introduced for the treatment of HF, not every drug may be well-tolerated by patients. In this narrative review, we describe a few of the newer classes of medications proposed to be efficacious in treating acute and chronic HF. We focus on vericiguat, omecamtiv mecarbil, ularitide, and serelaxin, and thoroughly examine their efficacy and safety profiles while summarizing the clinical trials of the drugs. There is a need for more long-term studies comparing the efficacy of these medications to the conventional ones.

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.

Cardiac and Renal Fibrosis, the Silent Killer in the Cardiovascular Continuum: An Up-to-Date

Cardiovascular disease (CVD) and chronic kidney disease (CKD) often coexist and have a major impact on patient prognosis. Organ fibrosis plays a significant role in the pathogenesis of cardio-renal syndrome (CRS), explaining the high incidence of heart failure and sudden cardiac death in these patients. Various mediators and mechanisms have been proposed as contributors to the alteration of fibroblasts and collagen turnover, varying from hemodynamic changes to the activation of the renin-angiotensin system, involvement of FGF 23, and Klotho protein or collagen deposition. A better understanding of all the mechanisms involved has prompted the search for alternative therapeutic targets, such as novel inhibitors of the renin-angiotensin-aldosterone system (RAAS), serelaxin, and neutralizing interleukin-11 (IL-11) antibodies. This review focuses on the molecular mechanisms of cardiac and renal fibrosis in the CKD and heart failure (HF) population and highlights the therapeutic alternatives designed to target the responsible pathways.

Femtosecond laser-induced fluorescence for rapid monitoring of cardiac troponin 1 as a cardiovascular disease biomarker

Medical diagnosis usually requires blood analysis of various biomarkers which are essential for disease detection and health status monitoring. Cardiac troponin 1 (cTn1) is a protein member of the cardiac troponin complex used for the diagnosis of several pathologies associated with cardiomyocyte necrosis. Laser-induced fluorescence (LIF) is a technique with high sensitivity and specificity, and it is one of the most significant developments used as an analytical tool for qualitative and quantitative analysis. The current study investigated the potential application of femtosecond LIF as a novel detection technique for rapid monitoring of cTn1 in clinical analysis. In the present study, the cTn1 (8 ng/ml) was excited over wavelengths ranging from 350 to 400 nm, and the LIF spectra were recorded. The results demonstrated that the maximum fluorescence intensity was observed at an excitation wavelength of 350 nm, with an emitted fluorescence peak centeredat 494 nm. At an excitation wavelength of 350 nm, different concentrations of cTn1 have been investigated and LIF spectra were obtained. The results revealed that the fluorescence peak intensity is concentration-dependent and increases linearly with increasing cTn1 concentration. These findings show that femtosecond LIF presents a unique, highly selective, precise, and direct approach to monitoring cTn1.

Clinical Review of Hypertensive Acute Heart Failure

Although acute heart failure (AHF) is a common disease associated with significant symptoms, morbidity and mortality, the diagnosis, risk stratification and treatment of patients with hypertensive acute heart failure (H-AHF) still remain a challenge in modern medicine. Despite great progress in diagnostic and therapeutic modalities, this disease is still accompanied by a high rate of both in-hospital (from 3.8% to 11%) and one-year (from 20% to 36%) mortality. Considering the high rate of rehospitalization (22% to 30% in the first three months), the treatment of this disease represents a major financial blow to the health system of each country. This disease is characterized by heterogeneity in precipitating factors, clinical presentation, therapeutic modalities and prognosis. Since heart decompensation usually occurs quickly (within a few hours) in patients with H-AHF, establishing a rapid diagnosis is of vital importance. In addition to establishing the diagnosis of heart failure itself, it is necessary to see the underlying cause that led to it, especially if it is de novo heart failure. Given that hypertension is a precipitating factor of AHF and in up to 11% of AHF patients, strict control of arterial blood pressure is necessary until target values are reached in order to prevent the occurrence of H-AHF, which is still accompanied by a high rate of both early and long-term mortality.

Standardized Definitions for Evaluation of Acute Decompensated Heart Failure Therapies: HF-ARC Expert Panel Paper

Acute decompensated heart failure (ADHF) is one of the most common reasons for hospitalizations or urgent care and is associated with poor outcomes. Therapies shown to improve outcomes are limited, however, and innovation in pharmacologic and device-based therapeutics are therefore actively being sought. Standardizing definitions for ADHF and its trajectory is complex, limiting the generalizability and translation of clinical trials to effect clinical care and policy change. The Heart Failure Collaboratory is a multistakeholder organization comprising clinical investigators, clinicians, patients, government representatives (including U.S. Food and Drug Administration and National Institutes of Health participants), payors, and industry collaborators. The following expert consensus document is the product of the Heart Failure Collaboratory convening with the Academic Research Consortium, including members from academia, the U.S. Food and Drug Administration, and industry, for the purposes of proposing standardized definitions for ADHF and highlighting important endpoint considerations to inform the design and conduct of clinical trials for drugs and devices in this clinical arena.

Associations between serum electrolyte and short-term outcomes in patients with acute decompensated heart failure

INTRODUCTION

There is a dearth of comprehensive studies on the association between serum electrolyte and adverse short-term prognosis of Chinese patients with acute decompensated heart failure (ADHF).

PATIENTS AND METHODS

A total of 5166 patients with ADHF were divided into four serum electrolyte-related study populations (potassium (n = 5145), sodium (n = 5135), chloride (n = 4966), serum total calcium (STC) (n = 4143)) under corresponding exclusions. Different logistic regression models were utilized to gauge the association between these electrolytes or the number of electrolyte abnormalities and the risk of a composite of all-cause mortality or 30-day heart failure (HF) readmission.

RESULTS

In multivariable adjusted analysis, patients with potassium below 3.5 mmol/L (odds ratios (ORs) 1.45; 95% confidence interval (CI):1.07-1.95), 4.01-4.50 mmol/L (OR: 1.29, CI: 1.02-1.62), 4.51-5.00 mmol/L (OR: 1.43, CI: 1.08-1.90) and above 5.00 mmol/L (OR: 1.74, CI: 1.21-2.51) had an increased risk of outcome when compared with potassium at 3.50-4.00 mmol/L. Sodium levels were inversely related to the risk of a composite outcome (<130 mmol/L: OR: 2.73 (95% CI, 1.81-4.12); 130-134 mmol/L: OR, 1.97 (CI, 1.45-2.68); 135-140 mmol/L: OR, 1.45 (CI, 1.17-1.81); p for trend < 0.001) in comparison with sodium at 141-145 mmol/L. Chloride < 95 mmol/L corresponded to a higher risk of a composite outcome with an OR of 1.65 (95% CI, 1.16-2.37) in contrast to chloride levels at 101-105 mmol/L. In addition, the adjusted ORs (95% CI) for a composite outcome comparing the STC < 2.00 and 2.00-2.24 vs. 2.25-2.58 mmol/L were 0.98 (0.69-1.43) and 1.13 (0.89-1.44), respectively. Besides that, the number of electrolyte abnormalities was positively related to the risk of a composite outcome (N = 1, OR 1.40, 95% CI: 1.13-1.73; N = 2, OR 2.51, 95% CI: 1.85-3.42; N = 3, OR 2.47, 95% CI: 1.45-4.19; p for trend < 0.001) in comparison with N = 0.

CONCLUSIONS

A deviation of potassium levels from 3.50 to 4.00 mmol/L, lower sodium levels and hypochloremia were associated with poorer short-term prognosis of ADHF. Furthermore, the number of electrolyte abnormalities positively correlated with adverse short-term prognosis of patients with ADHF. Key MessagesADHF patients with baseline serum potassium at first half part of normal range (3.50-4.00 mmol/L) may herald the lowest risk of recent cardiovascular events.Serum sodium and chloride levels exhibit discrepancies in terms of risk of short-term adverse events of ADHF patients.The number of electrolyte abnormalities is a significant predictor of poor short-term prognosis in patients with ADHF.

CLINICAL TRIAL REGISTRATION URL

http://www.chictr.org.cn/showproj.aspx?proj=23139. Unique identifier: ChiCTR-POC-17014020.

The role of relaxin in anterior cruciate ligament injuries: a systematic review

OBJECTIVE

Anterior cruciate ligament (ACL) tears are exceedingly common among the athletic population and are seen with higher incidence in females. Observational studies have noted peak ACL tear rates in the luteal phase of the menstrual cycle, a time in which the hormone relaxin peaks in serum concentration.

METHODS

A systematic review of the literature was performed. Inclusion criteria specified all prospective and retrospective studies which included the role of relaxin in the pathogenesis of ACL tears.

RESULTS

Six studies met inclusion criteria yielding 189 subjects from clinical studies and 51 in vitro samples. Included studies found that ACL samples exhibit selective relaxin binding. When pre-treated with estrogen prior to relaxin exposure, female ACL tissue samples exhibit increased expression of collagen degrading receptors.

CONCLUSION

Relaxin displays binding specificity to the female ACL and increased serum concentrations are correlated with increased ACL tear rates in female athletes. Further research is needed in this area.

LEVEL OF EVIDENCE

V.

Developing Clinical Risk Prediction Models for Worsening Heart Failure Events and Death by Left Ventricular Ejection Fraction

Background There is a need to develop electronic health record-based predictive models for worsening heart failure (WHF) events across clinical settings and across the spectrum of left ventricular ejection fraction (LVEF). Methods and Results We studied adults with heart failure (HF) from 2011 to 2019 within an integrated health care delivery system. WHF encounters were ascertained using natural language processing and structured data. We conducted boosted decision tree ensemble models to predict 1-year hospitalizations, emergency department visits/observation stays, and outpatient encounters for WHF and all-cause death within each LVEF category: HF with reduced ejection fraction (EF) (LVEF <40%), HF with mildly reduced EF (LVEF 40%-49%), and HF with preserved EF (LVEF ≥50%). Model discrimination was evaluated using area under the curve and calibration using mean squared error. We identified 338 426 adults with HF: 61 045 (18.0%) had HF with reduced EF, 49 618 (14.7%) had HF with mildly reduced EF, and 227 763 (67.3%) had HF with preserved EF. The 1-year risks of any WHF event and death were, respectively, 22.3% and 13.0% for HF with reduced EF, 17.0% and 10.1% for HF with mildly reduced EF, and 16.3% and 10.3% for HF with preserved EF. The WHF model displayed an area under the curve of 0.76 and mean squared error of 0.13, whereas the model for death displayed an area under the curve of 0.83 and mean squared error of 0.076. Performance and predictors were similar across WHF encounter types and LVEF categories. Conclusions We developed risk prediction models for 1-year WHF events and death across the LVEF spectrum using structured and unstructured electronic health record data and observed no substantial differences in model performance or predictors except for death, despite differences in underlying HF cause.

Development of Novel High-Affinity Antagonists for the Relaxin Family Peptide Receptor 1

H2 relaxin is a peptide hormone that exerts its biological actions through the G protein-coupled receptor, RXFP1. The numerous important biological functions of H2 relaxin, including potent renal, vasodilatory, cardioprotective, and anti-fibrotic actions, have resulted in considerable interest in its use as a therapeutic for various cardiovascular diseases and other fibrotic indications. Interestingly though, H2 relaxin and RXFP1 have been shown to be overexpressed in prostate cancer, allowing for the downregulation or blocking of relaxin/RXFP1 to decrease prostate tumor growth. These findings suggest the application of an RXFP1 antagonist for the treatment of prostate cancer. However, these therapeutically relevant actions are still poorly understood and have been hindered by the lack of a high-affinity antagonist. In this study, we chemically synthesized three novel H2 relaxin analogues that have complex insulin-like structures with two chains (A and B) and three disulfide bridges. We report here the structure-activity relationship studies on H2 relaxin that resulted in the development of a novel high-affinity RXFP1 antagonist, H2 B-R13HR (∼40 nM), that has only one extra methylene group in the side chain of arginine 13 in the B-chain (ArgB13) of H2 relaxin. Most notably, the synthetic peptide was shown to be active in a mouse model of prostate tumor growth in vivo where it inhibited relaxin-mediated tumor growth. Our compound H2 B-R13HR will be an important research tool to understand relaxin actions through RXFP1 and may be a potential lead compound for the treatment of prostate cancer.

Serelaxin Alleviates Fibrosis in Thyroid-Associated Ophthalmopathy via the Notch Pathway

Fibrosis is the late stage of thyroid-associated ophthalmopathy (TAO), resulting in serious complications. Effective therapeutic drugs are still lacking. We aimed to explore the mechanism of TAO fibrosis and to find a targeted drug. High-throughput RNA sequencing was performed on orbital connective tissues from twelve patients with TAO and six healthy controls. Protein-protein interaction (PPI) network was constructed using the Search Tool for the Retrieval of Interacting Genes (STRING) database and we identified the hub gene by Cytoscape software. Additionally, the RNA sequencing results were validated by quantitative real-time polymerase chain reaction (qRT-PCR). Bioinformatic prediction identified the functions of differentially expressed genes (DEGs). Further orbital connective tissue and serum samples of the TAO and control groups were collected for subsequent experiments. Histologic staining, Western blotting (WB), qRT-PCR, enzyme-linked immunosorbent assays (ELISAs), gene overexpression through lentiviral infection or silencing gene by short interfering RNA (siRNA) were performed. We found that the relaxin signaling pathway is an important regulatory pathway in TAO fibrosis pathogenesis. Serelaxin exerts antifibrotic and anti-inflammatory effects in TAO. Furthermore, the downstream Notch pathway was activated by serelaxin and was essential to the antifibrotic effect of serelaxin in TAO. The antifibrotic effect of serelaxin is dependent on RXFP1.

A Lipidated Single-B-Chain Derivative of Relaxin Exhibits Improved In Vitro Serum Stability without Altering Activity

Human relaxin-2 (H2 relaxin) is therapeutically very important due to its strong anti-fibrotic, vasodilatory, and cardioprotective effects. Therefore, relaxin’s receptor, relaxin family peptide receptor 1 (RXFP1), is a potential target for the treatment of fibrosis and related disorders, including heart failure. H2 relaxin has a complex two-chain structure (A and B) and three disulfide bridges. Our laboratory has recently developed B7-33 peptide, a single-chain agonist based on the B-chain of H2 relaxin. However, the peptide B7-33 has a short circulation time in vitro in serum (t1/2 = ~6 min). In this study, we report structure-activity relationship studies on B7-33 utilizing different fatty-acid conjugations at different positions. We have shown that by fatty-acid conjugation with an appropriate spacer length, the in vitro half-life of B7-33 can be increased from 6 min to 60 min. In the future, the lead lipidated molecule will be studied in animal models to measure its PK/PD properties, which will lead to their pre-clinical applications.

The single-chain relaxin mimetic, B7-33, maintains the cardioprotective effects of relaxin and more rapidly reduces left ventricular fibrosis compared to perindopril in an experimental model of cardiomyopathy

The hormone, relaxin (RLX), exerts various organ-protective effects independently of etiology. However, its complex two-chain and three disulphide bonded structure is a limitation to its preparation and affordability. Hence, a single chain-derivative of RLX, B7-33, was developed and shown to retain the anti-fibrotic effects of RLX in vitro and in vivo. Here, we determined whether B7-33 could retain the other cardioprotective effects of RLX, and also compared its therapeutic efficacy to the ACE inhibitor, perindopril. Adult male 129sv mice were subjected to isoprenaline (ISO; 25 mg/kg/day, s.c)-induced cardiomyopathy, then s.c-treated with either RLX (0.5 mg/kg/day), B7-33 (0.25 mg/kg/day; equivalent dose corrected for MW) or perindopril (1 mg/kg/day) from days 7-14 post-injury. Control mice received saline instead of ISO. Changes in animal body weight (BW) and systolic blood pressure (SBP) were measured weekly, whilst cardiomyocyte hypertrophy and measures of vascular dysfunction and rarefaction, left ventricular (LV) inflammation and fibrosis were assessed at day 14 post-injury. ISO-injured mice had significantly increased LV inflammation, cardiomyocyte hypertrophy, fibrosis, vascular rarefaction and aortic contractility in the absence of any changes in BW or SBP at day 14 post-injury. Both B7-33 and RLX equivalently reduced LV fibrosis and normalised the ISO-induced LV inflammation and cardiomyocyte hypertrophy, whilst restoring blood vessel density and aortic contractility. Comparatively, perindopril lowered SBP and the ISO-induced LV inflammation and vascular rarefaction, but not fibrosis or hypertrophy. As B7-33 retained the cardioprotective effects of RLX and provided rapid-occurring anti-fibrotic effects compared to perindopril, it could be considered as a cost-effective cardioprotective therapy.

Declining Risk of Sudden Cardiac Death in Heart Failure: Fact or Myth?

The notion that the risk of sudden cardiac death (SCD) in patients with heart failure (HF) is declining seems to be gaining traction. Numerous editorials and commentaries have suggested that SCD, specifically arrhythmic SCD, is no longer a significant risk for patients with HF on guideline-directed medical therapy. In this review, we question whether the risk of SCD has indeed declined in HF trials and in the real world. We also explore whether, despite relative risk reductions, the residual SCD risk after guideline-directed medical therapy still suggests a need for implantable cardioverter defibrillator therapy. Among our arguments is that SCD has not decreased in HF trials, nor in the real world. Moreover, we argue that data from HF trials, which have not adhered to guideline-directed device therapy, do not obviate or justify delays to implantable cardioverter defibrillator therapy. In this context, we underline the challenges of translating the findings of HF randomized, controlled trials of guideline-directed medical therapy to the real world. We also make the case for HF trials that adhere to current guideline-directed device therapy so that we can better understand the role of implantable cardioverter defibrillators in chronic HF.

Development of a long-acting relaxin analogue, LY3540378, for treatment of chronic heart failure

BACKGROUND AND PURPOSE

Chronic heart failure, a progressive disease with limited treatment options currently available, especially in heart failure with preserved ejection fraction (HFpEF), represents an unmet medical need as well as an economic burden. The development of a novel therapeutic to slow or reverse disease progression would be highly impactful to patients and society. Relaxin-2 (relaxin) is a human hormone regulating cardiovascular, renal, and pulmonary adaptations during pregnancy. A short-acting recombinant relaxin, Serelaxin, demonstrated short-term heart failure symptom relief and biomarker improvement in acute heart failure trials. Here, we present the development of a long-acting relaxin analogue to be tested in the treatment of chronic heart failure.

EXPERIMENTAL APPROACH

LY3540378 is a long-acting protein therapeutic composed of a human relaxin analogue and a serum albumin-binding VHH domain.

KEY RESULTS

LY3540378 is a potent agonist of the relaxin family peptide receptor 1 (RXFP1) and maintains selectivity against RXFP2/3/4 comparable to native relaxin. The half-life of LY3540378 in preclinical species is extended through high affinity binding of the albumin-binding VHH domain to serum albumin. When tested in a single dose administration, LY3540378 elicited relaxin-mediated pharmacodynamic responses, such as reduced serum osmolality and increased renal blood flow in rats. In an isoproterenol-induced cardiac hypertrophy mouse model, treatment with LY3540378 significantly reduced cardiac hypertrophy and improved isovolumetric relaxation time. In a monkey cardiovascular safety study, there were no adverse observations from administration of LY3540378.

CONCLUSION AND IMPLICATIONS

LY3540378 demonstrated to be a suitable clinical development candidate, and is progressing in clinical trials.

Effect of Rivaroxaban vs Enoxaparin on Major Cardiac Adverse Events and Bleeding Risk in the Acute Phase of Acute Coronary Syndrome: The H-REPLACE Randomized Equivalence and Noninferiority Trial

IMPORTANCE

Parenteral enoxaparin is a preferred anticoagulant used in the acute phase for patients with acute coronary syndrome (ACS). The safety and efficacy of short-term low-dose rivaroxaban in this clinical setting remain unknown.

OBJECTIVE

To compare the safety and efficacy of rivaroxaban vs enoxaparin in the acute phase of ACS.

DESIGN, SETTING, AND PARTICIPANTS

This multicenter, prospective, open-label, active-controlled, equivalence and noninferiority trial was conducted from January 2017 through May 2021 with a 6-month follow-up at 21 hospitals in China. Participants included patients with ACS missing the primary reperfusion window or before selective revascularization. Data were analyzed from November 2021 to November 2022.

INTERVENTIONS

Participants were randomized 1:1:1 to oral rivaroxaban 2.5 mg or 5 mg or 1 mg/kg subcutaneous enoxaparin twice daily in addition to dual antiplatelet therapy (DAPT; aspirin 100 mg and clopidogrel 75 mg once daily) for a mean of 3.7 days.

MAIN OUTCOMES AND MEASURES

The primary safety end point was bleeding events, as defined by the International Society on Thrombosis and Haemostasis, and the primary efficacy end point was major adverse cardiovascular events (MACEs), including cardiac death, myocardial infarction, rerevascularization, or stroke during the 6-month follow-up.

RESULTS

Of 2055 enrolled patients, 2046 (99.6%) completed the trial (mean [SD] age 65.8 [8.2] years, 1443 [70.5%] male) and were randomized to enoxaparin (680 patients), rivaroxaban 2.5 mg (683 patients), or rivaroxaban 5 mg (683 patients). Bleeding rates were 46 patients (6.8%) in the enoxaparin group, 32 patients (4.7%) in the rivaroxaban 2.5 mg group, and 36 patients (5.3%)in the rivaroxaban 5 mg group (rivaroxaban 2.5 mg vs enoxaparin: noninferiority hazard ratio [HR], 0.68; 95% CI, 0.43 to 1.07; P = .005; rivaroxaban 5 mg vs enoxaparin: noninferiority HR, 0.88; 95% CI, 0.70 to 1.09; P = .001). The incidence of MACEs was similar among groups, and noninferiority was reached in the rivaroxaban 5 mg group (HR, 0.60; 95% CI, 0.31 to 1.16, P = .02) but not in the rivaroxaban 2.5 mg group (HR, 0.68; 95% CI, 0.36 to 1.30; P = .05) compared with the enoxaparin group.

CONCLUSIONS AND RELEVANCE

In this equivalence and noninferiority trial, oral rivaroxaban 5 mg showed noninferiority to subcutaneous enoxaparin (1 mg/kg) for patients with ACS treated with DAPT during the acute phase. Results of this feasibility study provide useful information for designing future randomized clinical trials with sufficient sample sizes.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03363035.

Disconnect between the effects of serelaxin on renal function and outcome in acute heart failure

BACKGROUND

We aimed to study whether improvement in renal function by serelaxin in patients who were hospitalized for acute heart failure (HF) might explain any potential effect on clinical outcomes.

METHODS

We included 6318 patients from the RELAXin in AHF-2 (RELAX-AHF2) study. Improvement in renal function was defined as a decrease in serum creatinine of ≥ 0.3 mg/dL and ≥ 25%, or increase in estimated glomerular filtration rate of ≥ 25% between baseline and day 2. Worsening renal function (WRF) was defined as the reverse. We performed causal mediation analyses regarding 180-day all-cause mortality (ACM), cardiovascular death (CVD), and hospitalization for HF/renal failure.

RESULTS

Improvement in renal function was more frequently observed with serelaxin when compared with placebo [OR 1.88 (95% CI 1.64-2.15, p < 0.0001)], but was not associated with subsequent clinical outcomes. WRF occurred less frequent with serelaxin [OR 0.70 (95% CI 0.60-0.83, p < 0.0001)] and was associated with increased risk of ACM, worsening HF and the composite of CVD and HF or renal failure hospitalization. Improvement in renal function did not mediate the treatment effect of serelaxin [CVD HR 1.01 (0.99-1.04), ACM HR 1.01 (0.99-1.03), HF/renal failure hospitalization HR 0.99 (0.97-1.00)].

CONCLUSIONS

Despite the significant improvement in renal function by serelaxin in patients with acute HF, the potential beneficial treatment effect was not mediated by improvement in renal function. These data suggest that improvement in renal function might not be a suitable surrogate marker for potential treatment efficacy in future studies with novel relaxin agents in acute HF. Central illustration. Conceptual model explaining mediation analysis; treatment efficacy of heart failure therapies mediated by renal function.

Relaxin-2 plasma levels in atrial fibrillation are linked to inflammation and oxidative stress markers

Relaxin-2 exerts many favourable cardiovascular effects in pathological circumstances such as atrial fibrillation (AF) and heart failure, but the mechanisms underlying its actions are not completely understood. Since inflammation and fibrosis are pivotal processes in the pathogenesis of AF, our aim was to study the relationship between relaxin-2 plasma levels in left atrium (LA) and peripheral vein with molecules implicated in fibrosis, inflammation and oxidative stress in AF patients, and to evaluate the anti-fibrotic ability of relaxin-2 in normal human atrial cardiac fibroblasts (NHCF-A). Peripheral vein relaxin-2 plasma levels were higher than LA relaxin-2 plasma levels in men while, in women, peripheral vein relaxin-2 levels were increased compared to men. AF patients with higher levels of relaxin-2 exhibited a reduction in H₂O₂ plasma levels and in mRNA levels of alpha-defensin 3 (DEFA3) and IL-6 in leucocytes from LA plasma. Relaxin-2-in-vitro treatment inhibited NHCF-A migration and decreased mRNA and protein levels of the pro-fibrotic molecule transforming growth factor-β1 (TGF-β1). Our results support an association between relaxin-2 and molecules involved in fibrosis, inflammation and oxidative stress in AF patients, and reinforce an anti-fibrotic protective role of this hormone in NHCF-A; strengthening the relevance of relaxin-2 in AF physiopathology, diagnosis and treatment.

Innovations in medical therapy of heart failure with reduced ejection fraction

Heart failure with reduced ejection fraction (HFrEF) is a pathological condition still characterized by high rates of mortality and disease exacerbation frequently leading to hospitalization, thus there is a continuous need for pharmacological treatments impacting on disease stability and long-term prognosis. Moreover, the phenotype of heart failure patients is continuously changing over time, and the development of new heart failure drugs is crucial to promote a personalized and targeted approach. In recent years, several therapeutic innovations have emerged in the landscape of acute and chronic HFrEF, largely changing and improving our approach to the disease. Various studies on new drugs and experimental therapeutic approaches are ongoing. The present review discusses the latest data on both recently approved drugs and developing therapeutic targets, in order to provide a critical overview for an informed and optimal approach to such a complex disease.

Association between tricuspid annular systolic velocity and poor short-term prognosis in patients with acute decompensated heart failure

BACKGROUND

There is scant data on the association of the Pulsed wave-Doppler tissue imaging (PW-DTI)-derived tricuspid lateral annular peak systolic velocity (S') and poor short-term prognosis of patients with acute decompensated heart failure (ADHF).

PATIENTS AND METHODS

A total number of 732 participants from the Heb-ADHF registry in China were divided into three groups according to the corresponding status of tricuspid S'. Demographic characteristics, comorbidities, physical examinations, lab tests, and medications were compared among the different groups. Different logistic regression models were utilized to gauge the relationship between S' and the risk of a composite of short-term all-cause mortality or 30-day heart failure (HF)-related rehospitalization.

RESULTS

The number of composite outcome events identified in the study population was 85, with the short-term all-cause death coupled with 30-day HF readmission events reaching 23 and 62, respectively. As per the multivariable adjusted analysis, S' was inversely related to the risk of a composite outcome [<10 cm/s odds ratios (OR) 2.90, 95% confidence interval (CI):1.33-6.31; 10-11 cm/s OR 2.18, 95% CI: 1.10-4.33; p for trend = 0.006] in comparison with S' at >11 cm/s. When S' was analysed as a continuous variable, per 1 cm/s increase, the OR (95% CI) for a composite outcome was [0.87 (0.77-0.99), p = 0.028]. Area under curve (AUC) of S' for predicting outcome of ADHF was 0.631 (95%CI: 0.573-0.690, p < 0.01). Significant inverse association was also observed in left ventricular ejection fraction (LVEF) ≥40% subgroup.

CONCLUSIONS

Inspite of the potential confounders, a more impaired tricuspid annular peak systolic velocity is associated with a poorer short-term prognosis of patients with ADHF.

Evaluation of preoperative duloxetine use for postoperative analgesia following laparoscopic cholecystectomy: A randomized controlled trial

Background: The pain pattern after laparoscopic cholecystectomy (LC) is complex and distinct from postoperative pain after other laparoscopic procedures, suggesting that procedure-specific optimal analgesic management plans should be proposed. Duloxetine, a non-opioid neuromodulator, has been widely used to manage pain with dual central and peripheral analgesic properties.

Aims: To assess the effect of preoperative administration of duloxetine compared to placebo on postoperative pain control in patients undergoing LC.

Patients and Methods: This study was a randomized, parallel-group, placebo-controlled, double-blinded study performed on patients undergoing LC. Patients were randomly divided into two groups of 30 each on the day of surgery in the preoperative holding area, using a computer-generated random number to receive 60 mg duloxetine as a single oral dose 2 h before the procedure or placebo. The primary outcome was the difference in the mean of visual analogue scale (VAS) scores between the two studied groups, as measured by the area under the curve (AUC) of the VAS scores.

Results: The derived AUC of VAS scores in the duloxetine group (757.89 ± 326.01 mm × h) was significantly lower than that calculated for the control group (1005.1 ± 432.5 mm × h). The mean postoperative VAS scores recorded at 4 and 24 h were statistically different between the study groups (p = 0.041 and 0.003, respectively). As observed in the survival curve analysis, there was no significant difference (p = 0.665) for the time until the patient’s first request for rescue medications in the two groups. The frequency of postoperative nausea and vomiting (PONV) was lower in patients of the duloxetine group than that recorded in those allocated to the control group at 8 and 24-h time intervals (p = 0.734 and 0.572, respectively).

Conclusion: Preoperative use of duloxetine reduces postoperative pain significantly compared with placebo. In addition, its use is associated with a reduction in PONV. These preliminary findings suggest that duloxetine could play a role in the acute preoperative period for patients undergoing LC.

Clinical Trial Registration: [https://clinicaltrials.gov/ct2/show/NCT05115123, identifier NCT05115123],

'Acute Heart Failure': Should We Abandon the Term Altogether?

PURPOSE OF REVIEW

The distinction between 'acute' and 'chronic' heart failure persists. Our review aims to explore whether reclassifying heart failure decompensation more accurately as an event within the natural history of chronic heart failure has the potential to improve outcomes.

RECENT FINDINGS

Although hospitalisation for worsening heart failure confers a poor prognosis, much of this reflects chronic disease severity. Most patients survive hospitalisation with most deaths occurring in the post-discharge 'vulnerable phase'. Current evidence supports four classes of medications proven to reduce cardiovascular mortality for those who have heart failure with a reduced ejection fraction, with recent trials suggesting worsening heart failure events are opportunities to optimise these therapies. Abandoning the term 'acute heart failure' has the potential to give greater priority to initiating proven pharmacological and device therapies during decompensation episodes, in order to improve outcomes for those who are at the greatest risk.

Liposomal Entrapment or Chemical Modification of Relaxin2 for Prolongation of Its Stability and Biological Activity

Relaxin (RLX) is a protein that is structurally similar to insulin and has interesting biological activities. As with all proteins, preservation of RLX’s structural integrity/biological functionality is problematic. Herein, we investigated two methods for increasing the duration of relaxin-2’s (RLX2) biological activity: synthesis of a palmitoyl RLX2 conjugate (P-RLX2) with the use of a Palmitoyl-l-Glu-OtBu peptide modifier, and encapsulation into liposomes of P-RLX2, RLX2, and its oxidized form (O-RLX2). For liposomal encapsulation thin-film hydration and DRV methods were applied, and different lipid compositions were tested for optimized protein loading. RLX2 and O-RLX2 were quantified by HPLC. The capability of the peptides/conjugate to stimulate transfected cells to produce cyclic adenosine monophosphate (cAMP) was used as a measure of their biological activity. The stability and bioactivity of free and liposomal RLX2 types were monitored for a 30 d period, in buffer (in some cases) and bovine serum (80%) at 37 °C. The results showed that liposome encapsulation substantially increased the RLX2 integrity in buffer; PEGylated liposomes demonstrated a higher protection. Liposome encapsulation also increased the stability of RLX2 and O-RLX2 in serum. Considering the peptide’s biological activity, cAMP production of RLX2 was higher than that of the oxidized form and the P-RLX2 conjugate (which demonstrated a similar activity to O-RLX2 when measured in buffer, but lower when measured in the presence of serum proteins), while liposome encapsulation resulted in a slight decrease of bioactivity initially, but prolonged the peptide bioactivity during incubation in serum. It was concluded that liposome encapsulation of RLX2 and synthetic modification to P-RLX2 can both prolong RLX2 peptide in vitro stability; however, the applied chemical conjugation results in a significant loss of bioactivity (cAMP production), whereas the effect of liposome entrapment on RLX2 activity was significantly lower.

Efficacy of pharmacologic therapies in patients with acute heart failure: A network meta-analysis

Background: A network meta-analysis (NMA) of the current recommended drugs for the treatment of acute heart failure (AHF), was performed to compare the relative efficacy.

Methods: We used PubMed, EMBASE, Cochrane Clinical Trials Register, and Web of Science systems to search studies of randomized controlled trials (RCT) for the treatment of AHF recommended by the guidelines and expert consensus until 1 December 2020. The primary outcome was all-cause mortality within 30 days. The secondary outcomes included 30-days all-cause rehospitalization, rates of HF-related rehospitalization, rates of adverse events, and rates of serious adverse events. A Bayesian NMA based on random effects model was performed.

Results: After screening 14,888 citations, 23 RCTs (17,097 patients) were included, focusing on nesiritide, placebo, serelaxin, rhANP, omecamtiv mecarbil, tezosentan, KW-3902, conivaptan, tolvaptan, TRV027, chlorothiazide, metolazone, ularitide, relaxin, and rolofylline. Omecamtiv mecarbil had significantly lower all-cause mortality rates than the placebo (odds ratio 0.04, 0.01–0.22), rhANP (odds ratio 0.03, 0–0.40), serelaxin (odds ratio 0.05, 0.01–0.38), tezosentan (odds ratio 0.04, 0–0.22), tolvaptan (odds ratio 0.04, 0.01–0.30), and TRV027 (odds ratio 0.03, 0–0.36). No drug was superior to the other drugs for the secondary outcomes and safety outcomes.

Conclusion: No drug was superior to the other drugs for the secondary outcomes and safety outcomes. Current drugs for AHF show similar efficacy and safety.

Synthetic short-chain peptide analogues of H1 relaxin lack affinity for the RXFP1 receptor and relaxin-like bioactivity. Clues to a better understanding of relaxin agonist design

The peptide hormone relaxin (RLX), also available as clinical-grade recombinant protein (serelaxin), holds great promise as a cardiovascular and anti-fibrotic agent but is limited by the pharmacokinetic issues common to all peptide drugs. In this study, by a computational modelling chemistry approach, we have synthesized and tested a set of low molecular weight peptides based on the putative receptor-binding domain of the B chain of human H1 RLX isoform, with the objective to obtain RLX analogues with improved pharmacokinetic features. Some of them were stabilized to induce the appropriate 3-D conformation by intra-chain tri-azolic staples, which should theoretically enhance their resistance to digestive enzymes making them suited for oral administration. Despite these favourable premises, none of these H1 peptides, either linear or stapled, revealed a sufficient affinity to the specific RLX receptor RXFP1. Moreover, none of them was endowed with any RLX-like biological effects in RXFP1-expressing THP-1 human monocytic cells and mouse NIH-3T3-derived myofibroblasts in in vitro culture, in terms of significantly relevant cAMP elevation and ERK1/2 phosphorylation, which represent two major signal transduction events downstream RXFP1 activation. This was at variance with authentic serelaxin, which induced a clear-cut, significant activation of both these classical RLX signaling pathways. Albeit negative, the results of this study offer additional information about the structural requirements that new peptide therapeutics shall possess to effectively behave as RXFP1 agonists and RLX analogues.

Neutrophil-to-Lymphocyte Ratio and Outcomes in Patients Admitted for Acute Heart Failure (As Seen in the BLAST-AHF, Pre-RELAX-AHF, and RELAX-AHF Studies)

Previous studies have suggested that the neutrophil-to-lymphocyte ratio (NLR) is a novel yet readily evaluable inflammatory biomarker that may be useful for determining cardiovascular prognosis during acute episodes. The study investigated the role of NLR in predicting cardiovascular (CV) outcomes in patients with acute heart failure (HF). Individual patient data from the BLAST-AHF (phase 2b study of the biased ligand of the angiotensin 2 type 1 receptor, TRV027), Pre-RELAX-AHF (phase 2b study of recombinant human relaxin-2, serelaxin), and RELAX-AHF (phase 3 study of serelaxin) randomized, placebo-controlled studies for patients with acute HF were pooled for analysis. Dyspnea visual analog scale area under the curve through day 5, worsening HF through day 5, 30-day all-cause mortality, 60-day HF/renal failure rehospitalizations or CV death, 180-day all-cause mortality, and 180-day CV death were assessed. There were several differences in the baseline characteristics of the patients divided by NLR tertile, with patients in the higher NLR having worse clinical characteristics. NLR was an independent predictor of 30-day all-cause mortality (adjusted hazard ratio [HR] per log₂ NLR increment: 1.66 [1.22 to 2.25], p = 0.001), 60-day HF/renal failure rehospitalizations or CV death: 1.33 [1.12 to 1.57], p = 0.001), 180-day all-cause mortality (adjusted HR 1.27 [1.08 to 1.50], p = 0.003), and 180-day CV death (adjusted HR 1.24 [1.04 to 1.49], p = 0.018). NLR, a readily available inflammatory biomarker, was associated with independent risk for short- and long-term adverse outcomes in acute HF, surpassing traditional markers, such as natriuretic peptides.

Relaxin does not prevent development of hypoxia-induced pulmonary edema in rats

Acute hypoxia impairs left ventricular (LV) inotropic function and induces development of pulmonary edema (PE). Enhanced and uneven hypoxic pulmonary vasoconstriction is an important pathogenic factor of hypoxic PE. We hypothesized that the potent vasodilator relaxin might reduce hypoxic pulmonary vasoconstriction and prevent PE formation. Furthermore, as relaxin has shown beneficial effects in acute heart failure, we expected that relaxin might also improve LV inotropic function in hypoxia. Forty-two rats were exposed over 24 h to normoxia or hypoxia (10% N₂ in O₂). They were infused with either 0.9% NaCl solution (normoxic/hypoxic controls) or relaxin at two doses (15 and 75 μg kg⁻¹ day⁻¹). After 24 h, hemodynamic measurements and bronchoalveolar lavage were performed. Lung tissue was obtained for histological and immunohistochemical analyses. Hypoxic control rats presented significant depression of LV systolic pressure by 19% and of left and right ventricular contractility by about 40%. Relaxin did not prevent the hypoxic decrease in LV inotropic function, but re-increased right ventricular contractility. Moreover, hypoxia induced moderate interstitial PE and inflammation in the lung. Contrasting to our hypothesis, relaxin did not prevent hypoxia-induced pulmonary edema and inflammation. In hypoxic control rats, PE was similarly distributed in the apical and basal lung lobes. In relaxin-treated rats, PE index was 35–40% higher in the apical than in the basal lobe, which is probably due to gravity effects. We suggest that relaxin induced exaggerated vasodilation, and hence pulmonary overperfusion. In conclusion, the results show that relaxin does not prevent but rather may aggravate PE formation.

Relaxin-2 as a Potential Biomarker in Cardiovascular Diseases

The pleiotropic hormone relaxin-2 plays a pivotal role in the physiology and pathology of the cardiovascular system. Relaxin-2 exerts relevant regulatory functions in cardiovascular tissues through the specific receptor relaxin family peptide receptor 1 (RXFP1) in the regulation of cardiac metabolism; the induction of vasodilatation; the reversion of fibrosis and hypertrophy; the reduction of inflammation, oxidative stress, and apoptosis; and the stimulation of angiogenesis, with inotropic and chronotropic effects as well. Recent preclinical and clinical outcomes have encouraged the potential use of relaxin-2 (or its recombinant form, known as serelaxin) as a therapeutic strategy during cardiac injury and/or in patients suffering from different cardiovascular disarrangements, especially heart failure. Furthermore, relaxin-2 has been proposed as a promising biomarker of cardiovascular health and disease. In this review, we emphasize the relevance of the endogenous hormone relaxin-2 as a useful diagnostic biomarker in different backgrounds of cardiovascular pathology, such as heart failure, atrial fibrillation, myocardial infarction, ischemic heart disease, aortic valve disease, hypertension, and atherosclerosis, which could be relevant in daily clinical practice and could contribute to comprehending the specific role of relaxin-2 in cardiovascular diseases.

Endpoints: types, selection, interpretation of the results obtained on the example of cardiology studies

The importance of high-quality randomized controlled trials cannot be overemphasized. Each such study attempts to answer a specific clinical question. To do this, it is necessary to determine in advance the indicator of achievement of a specific result for a certain period of time. This indicator is the endpoint (EP) of the study, i.e. one or another outcome of the disease or a change in the laboratory and functional characteristics. Its choice directly affects the intended design and sample size of the study. The article provides a classification and hierarchy of EPs (depending on the purpose), describes the features and limitations of the use of important clinical outcomes and surrogate indicators. The reasons why composite EPs are widely used in cardiology studies are described. Special attention should be paid to EP interpretation within secondary analysis, a positive result of which can only be assessed if a treatment effect is demonstrated in terms of the primary indicator of efficacy or safety. The current review is supplemented by clinical examples of cardiology studies.

Efficacy of Nondiuretic Pharmacotherapy for Improving the Treatment of Congestion in Patients with Acute Heart Failure: A Systematic Review of Randomised Controlled Trials

Diuretic therapy is the mainstay during episodes of acute heart failure (AHF). Diuretic resistance is often encountered and poses a substantial challenge for clinicians. There is a lack of evidence on the optimal strategies to tackle this problem. This review aimed to compare the outcomes associated with congestion management based on a strategy of pharmacological nondiuretic-based regimens. The PubMed, Cochrane Library, Scopus, and ScienceDirect databases were systematically searched for all randomised controlled trials (RCTs) of adjuvant pharmacological treatments used during hospitalisation episodes of AHF patients. Congestion relief constitutes the main target in AHF; hence, only studies with efficacy indicators related to decongestion enhancement were included. The Cochrane risk-of-bias tool was used to evaluate the methodological quality of the included RCTs. Twenty-three studies were included; dyspnea relief constituted the critical efficacy endpoint in most included studies. However, substantial variations in dyspnea measurement were found. Tolvaptan and serelaxin were found to be promising options that might improve decongestion in AHF patients. However, further high-quality RCTs using a standardised approach to diuretic management, including dosing and monitoring strategies, are crucial to provide new insights and recommendations for managing heart failure in acute settings.