Interleukin-1 Blockade in Cardiovascular Diseases: From Bench to Bedside

Role of inflammation and evidence for the use of colchicine in patients with acute coronary syndrome

Acute Coronary Syndrome (ACS) significantly contributes to cardiovascular death worldwide. ACS may arise from the disruption of an atherosclerotic plaque, ultimately leading to acute ischemia and myocardial infarction. In the pathogenesis of atherosclerosis, inflammation assumes a pivotal role, not solely in the initiation and complications of atherosclerotic plaque formation, but also in the myocardial response to ischemic insult. Acute inflammatory processes, coupled with time to reperfusion, orchestrate ischemic and reperfusion injuries, dictating infarct magnitude and acute left ventricular (LV) remodeling. Conversely, chronic inflammation, alongside neurohumoral activation, governs persistent LV remodeling. The interplay between chronic LV remodeling and recurrent ischemic episodes delineates the progression of the disease toward heart failure and cardiovascular death. Colchicine exerts anti-inflammatory properties affecting both the myocardium and atherosclerotic plaque by modulating the activity of monocyte/macrophages, neutrophils, and platelets. This modulation can potentially result in a more favorable LV remodeling and forestalls the recurrence of ACS. This narrative review aims to delineate the role of inflammation across the different phases of ACS pathophysiology and describe the mechanistic underpinnings of colchicine, exploring its purported role in modulating each of these stages.

Use of Silica Nanoparticles for Drug Delivery in Cardiovascular Disease

PURPOSE

Cardiovascular disease (CVD) is the leading cause of death worldwide. The current CVD therapeutic drugs require long-term treatment with high doses, which increases the risk of adverse effects while offering only marginal treatment efficacy. Silica nanoparticles (SNPs) have been proven to be an efficient drug delivery vehicle for numerous diseases, including CVD. This article reviews recent progress and advancement in targeted delivery for drugs and diagnostic and theranostic agents using silica nanoparticles to achieve therapeutic efficacy and improved detection of CVD in clinical and preclinical settings.

METHODS

A search of PubMed, Scopus, and Google Scholar databases from 1990 to 2023 was conducted. Current clinical trials on silica nanoparticles were identified through ClinicalTrials.gov. Search terms include silica nanoparticles, cardiovascular diseases, drug delivery, and therapy.

FINDINGS

Silica nanoparticles exhibit biocompatibility in biological systems, and their shape, size, surface area, and surface functionalization can be customized for the safe transport and protection of drugs in blood circulation. These properties also enable effective drug uptake in specific tissues and controlled drug release after systemic, localized, or oral delivery. A range of silica nanoparticles have been used as nanocarrier for drug delivery to treat conditions such as atherosclerosis, hypertension, ischemia, thrombosis, and myocardial infarction.

IMPLICATIONS

The use of silica nanoparticles for drug delivery and their ongoing development has emerged as a promising strategy to improve the effectiveness of drugs, imaging agents, and theranostics with the potential to revolutionize the treatment of CVD.

Recent Advances in Anti-Atherosclerosis and Potential Therapeutic Targets for Nanomaterial-Derived Drug Formulations

Atherosclerosis, the leading cause of death worldwide, is responsible for ≈17.6 million deaths globally each year. Most therapeutic drugs for atherosclerosis have low delivery efficiencies and significant side effects, and this has hampered the development of effective treatment strategies. Diversified nanomaterials can improve drug properties and are considered to be key for the development of improved treatment strategies for atherosclerosis. The pathological mechanisms underlying atherosclerosis is summarized, rationally designed nanoparticle-mediated therapeutic strategies, and potential future therapeutic targets for nanodelivery. The content of this study reveals the potential and challenges of nanoparticle use for the treatment of atherosclerosis and highlights new effective design ideas.

A superior extracellular matrix binding motif to enhance the regenerative activity and safety of therapeutic proteins

Among therapeutic proteins, cytokines and growth factors have great potential for regenerative medicine applications. However, these molecules have encountered limited clinical success due to low effectiveness and major safety concerns, highlighting the need to develop better approaches that increase efficacy and safety. Promising approaches leverage how the extracellular matrix (ECM) controls the activity of these molecules during tissue healing. Using a protein motif screening strategy, we discovered that amphiregulin possesses an exceptionally strong binding motif for ECM components. We used this motif to confer the pro-regenerative therapeutics platelet-derived growth factor-BB (PDGF-BB) and interleukin-1 receptor antagonist (IL-1Ra) a very high affinity to the ECM. In mouse models, the approach considerably extended tissue retention of the engineered therapeutics and reduced leakage in the circulation. Prolonged retention and minimal systemic diffusion of engineered PDGF-BB abolished the tumour growth-promoting adverse effect that was observed with wild-type PDGF-BB. Moreover, engineered PDGF-BB was substantially more effective at promoting diabetic wound healing and regeneration after volumetric muscle loss, compared to wild-type PDGF-BB. Finally, while local or systemic delivery of wild-type IL-1Ra showed minor effects, intramyocardial delivery of engineered IL-1Ra enhanced cardiac repair after myocardial infarction by limiting cardiomyocyte death and fibrosis. This engineering strategy highlights the key importance of exploiting interactions between ECM and therapeutic proteins for developing effective and safer regenerative therapies.

Molecularly targeted nanomedicine enabled by inorganic nanoparticles for atherosclerosis diagnosis and treatment

Atherosclerosis, a chronic cardiovascular disease caused by plaque development in arteries, remains a leading cause of morbidity and mortality. Atherosclerotic plaques are characterized by the expression and regulation of key molecules such as cell surface receptors, cytokines, and signaling pathway proteins, potentially facilitating precise diagnosis and treatment on a molecular level by specifically targeting the characteristic molecules. In this review, we highlight the recent progress in the past five years on developing molecularly targeted nanomedicine for imaging detection and treatment of atherosclerosis with the use of inorganic nanoparticles. Through targeted delivery of imaging contrast nanoparticles to specific molecules in atherogenesis, atherosclerotic plaque development at different stages could be identified and monitored via various molecular imaging modalities. We also review molecularly targeted therapeutic approaches that target and regulate molecules associated with lipid regulation, inflammation, and apoptosis. The review is concluded with discussion on current challenges and future development of nanomedicine for atherosclerotic diagnosis and treatment.

Tropoelastin Improves Post-Infarct Cardiac Function

BACKGROUND

Myocardial infarction (MI) is among the leading causes of death worldwide. Following MI, necrotic cardiomyocytes are replaced by a stiff collagen-rich scar. Compared to collagen, the extracellular matrix protein elastin has high elasticity and may have more favorable properties within the cardiac scar. We sought to improve post-MI healing by introducing tropoelastin, the soluble subunit of elastin, to alter scar mechanics early after MI.

METHODS AND RESULTS

We developed an ultrasound-guided direct intramyocardial injection method to administer tropoelastin directly into the left ventricular anterior wall of rats subjected to induced MI. Experimental groups included shams and infarcted rats injected with either PBS vehicle control or tropoelastin. Compared to vehicle treated controls, echocardiography assessments showed tropoelastin significantly improved left ventricular ejection fraction (64.7±4.4% versus 46.0±3.1% control) and reduced left ventricular dyssynchrony (11.4±3.5 ms versus 31.1±5.8 ms control) 28 days post-MI. Additionally, tropoelastin reduced post-MI scar size (8.9±1.5% versus 20.9±2.7% control) and increased scar elastin (22±5.8% versus 6.2±1.5% control) as determined by histological assessments. RNA sequencing (RNAseq) analyses of rat infarcts showed that tropoelastin injection increased genes associated with elastic fiber formation 7 days post-MI and reduced genes associated with immune response 11 days post-MI. To show translational relevance, we performed immunohistochemical analyses on human ischemic heart disease cardiac samples and showed an increase in tropoelastin within fibrotic areas. Using RNA-seq we also demonstrated the tropoelastin gene ELN is upregulated in human ischemic heart disease and during human cardiac fibroblast-myofibroblast differentiation. Furthermore, we showed by immunocytochemistry that human cardiac fibroblast synthesize increased elastin in direct response to tropoelastin treatment.

CONCLUSIONS

We demonstrate for the first time that purified human tropoelastin can significantly repair the infarcted heart in a rodent model of MI and that human cardiac fibroblast synthesize elastin. Since human cardiac fibroblasts are primarily responsible for post-MI scar synthesis, our findings suggest exciting future clinical translation options designed to therapeutically manipulate this synthesis.

Novel Targets for a Combination of Mechanical Unloading with Pharmacotherapy in Advanced Heart Failure

LVAD therapy is an effective rescue in acute and especially chronic cardiac failure. In several scenarios, it provides a platform for regeneration and sustained myocardial recovery. While unloading seems to be a key element, pharmacotherapy may provide powerful tools to enhance effective cardiac regeneration. The synergy between LVAD support and medical agents may ensure satisfying outcomes on cardiomyocyte recovery followed by improved quality and quantity of patient life. This review summarizes the previous and contemporary strategies for combining LVAD with pharmacotherapy and proposes new therapeutic targets. Regulation of metabolic pathways, enhancing mitochondrial biogenesis and function, immunomodulating treatment, and stem-cell therapies represent therapeutic areas that require further experimental and clinical studies on their effectiveness in combination with mechanical unloading.

Interleukin 1 receptor antagonism abrogates acute pressure-overload induced murine heart failure

BACKGROUND

Recent clinical trials have suggested that blockade of interleukin-1 can favorably impact patients with myocardial infarction and heart failure. However, the mechanism of how antagonism of this specific cytokine in mediating cardiac disease remains unclear. Hence, we sought to determine the influence of IL-1 blockade on acute hypertensive remodeling.

METHODS

Transverse aortic constriction (TAC) was performed in C57BL mice with or without intraperitoneal administration of interleukin 1 receptor antagonism (IL-1ra). Function, structure, and molecular diagnostics were subsequently performed and analyzed.

RESULTS

Six weeks after TAC, a progressive decline of ejection fraction and increases in LV mass and dimensions was effectively mitigated with IL-1ra. TAC resulted in an expected profile of hypertrophic markers including myosin heavy chain, atrial natriuretic peptide, and skeletal muscle actin which were all significantly lower in IL-1ra treated mice. While trichrome staining 2-weeks post TAC demonstrated similar levels of fibrosis, IL-1ra reduced expression of collagen-1, TIMP1, and periostin. Investigating the angiogenic response to pressure overload, similar levels of VEGF were observed, but IL-1ra was associated with more SDF-1. Immune cell infiltration (macrophages and lymphocytes) was also decreased in IL-1ra treated mice. Similarly, cytokine concentrations of IL-1, IL-18, and IL-6 were all reduced in IL-1ra-treated animals.

CONCLUSIONS

IL-1ra prevents the progression towards heart failure associated with acute pressure overload. This functional response was associated with reductions in mediators of fibrosis, cellular infiltration, and cytokine production. These results provide mechanistic insight into recent clinical trials and could springboard future investigations in patients with pressure-overload based cardiomyopathies.

Worsening baroreflex sensitivity on progression to type 2 diabetes: localized vs. systemic inflammation and role of antidiabetic therapy

Cardiac autonomic neuropathy (CAN) is an early cardiovascular manifestation of type 2 diabetes (T2D) that constitutes an independent risk factor for cardiovascular mortality and morbidity. Nevertheless, its underlying pathophysiology remains poorly understood. We recently showed that localized perivascular adipose tissue (PVAT) inflammation underlies the incidence of parasympathetic CAN in prediabetes. Here, we extend our investigation to provide a mechanistic framework for the evolution of autonomic impairment as the metabolic insult worsens. Early metabolic dysfunction was induced in rats fed a mild hypercaloric diet. Two low-dose streptozotocin injections were used to evoke a state of late decompensated T2D. Cardiac autonomic function was assessed by invasive measurement of baroreflex sensitivity using the vasoactive method. Progression into T2D was associated with aggravation of CAN to include both sympathetic and parasympathetic arms. Unlike prediabetic rats, T2D rats showed markers of brainstem neuronal injury and inflammation as well as increased serum levels of IL-1β. Experiments on PC12 cells differentiated into sympathetic-like neurons demonstrated that brainstem injury observed in T2D rats resulted from exposure to possible proinflammatory mediators in rat serum rather than a direct effect of the altered metabolic profile. CAN and the associated cardiovascular damage in T2D only responded to combined treatment with insulin to manage hyperglycemia in addition to a nonhypoglycemic dose of metformin or pioglitazone providing an anti-inflammatory effect, coincident with the effect of these combinations on serum IL-1β. Our present results indicate that CAN worsening upon progression to T2D involves brainstem inflammatory changes likely triggered by systemic inflammation.

Anakinra for constrictive pericarditis associated with incessant or recurrent pericarditis

Objective

Frequent flares of pericardial inflammation in recurrent or incessant pericarditis with corticosteroid dependence and colchicine resistance may represent a risk factor for constrictive pericarditis (CP). This study was aimed at the identification of CP in these patients, evaluating the efficacy and safety of anakinra, a third-line treatment based on interleukin-1 inhibition, to treat CP and prevent the need for pericardiectomy.

Methods

Consecutive patients with recurrent or incessant pericarditis with corticosteroid dependence and colchicine resistance were included in a prospective cohort study from 2015 to 2018. Enrolled patients received anakinra 100 mg once daily subcutaneously. The primary end point was the occurrence of CP. A clinical and echocardiographic follow-up was performed at 1, 3, 6 months and then every 6 months.

Results

Thirty-nine patients (mean age 42 years, 67% females) were assessed, with a baseline recurrence rate of 2.76 flares/patient-year and a median disease duration of 12 months (IQR 9–20). During follow-up, CP was diagnosed in 8/39 (20%) patients. After anakinra dose of 100 mg/day, 5 patients (63%) had a complete resolution of pericardial constriction within a median of 1.2 months (IQR 1–4). In other three patients (37%), CP became chronic, requiring pericardiectomy within a median of 2.8 months (IQR 2–5). CP occurred in 11 patients (28%) with incessant course, which was associated with an increased risk of CP over time (HR for CP 30.6, 95% CI 3.69 to 253.09).

Conclusions

In patients with recurrent or incessant pericarditis, anakinra may have a role in CP reversal. The risk of CP is associated with incessant rather than recurrent course.

Role for Anti-Cytokine Therapies in Severe Coronavirus Disease 2019

The causative agent for coronavirus disease 2019, severe acute respiratory syndrome coronavirus 2, appears exceptional in its virulence and immunopathology. In some patients, the resulting hyperinflammation resembles a cytokine release syndrome. Our knowledge of the immunopathogenesis of coronavirus disease 2019 is evolving and anti-cytokine therapies are under active investigation. This narrative review summarizes existing knowledge of the immune response to coronavirus infection and highlights the current and potential future roles of therapeutic strategies to combat the hyperinflammatory response of patients with coronavirus disease 2019.

DATA SOURCES

Relevant and up-to-date literature, media reports, and author experiences were included from Medline, national newspapers, and public clinical trial databases.

STUDY SELECTION

The authors selected studies for inclusion by consensus.

DATA EXTRACTION

The authors reviewed each study and selected approrpriate data for inclusion through consensus.

DATA SYNTHESIS

Hyperinflammation, reminiscent of cytokine release syndromes such as macrophage activation syndrome and hemophagocytic lymphohistiocytosis, appears to drive outcomes among adults with severe coronavirus disease 2019. Cytokines, particularly interleukin-1 and interleukin-6, appear to contribute importantly to such systemic hyperinflammation. Ongoing clinical trials will determine the efficacy and safety of anti-cytokine therapies in coronavirus disease 2019. In the interim, anti-cytokine therapies may provide a treatment option for adults with severe coronavirus disease 2019 unresponsive to standard critical care management, including ventilation.

CONCLUSIONS

This review provides an overview of the current understanding of the immunopathogenesis of coronavirus disease 2019 in adults and proposes treatment considerations for anti-cytokine therapy use in adults with severe disease.

Inhibiting NLRP3 Inflammasome Activity in Acute Myocardial Infarction: A Review of Pharmacologic Agents and Clinical Outcomes

The NLRP3 inflammasome is an intracellular, multimeric protein complex that initiates a potent inflammatory response to danger signals. After acute myocardial infarction, NLRP3 inflammasome-dependent inflammation promotes adverse left ventricular remodeling and recurrent atherosclerotic events. Selective and nonselective inhibitors of the NLRP3 inflammasome or its downstream effectors (interleukin-1β and interleukin-18) may prevent adverse left ventricular remodeling and recurrent atherosclerotic events. In this review, we highlight strategies to inhibit NLRP3 inflammasome activity and their potential roles in the management of acute myocardial infarction.

Interleukin-1 and the Inflammasome as Therapeutic Targets in Cardiovascular Disease

The intracellular sensing protein termed NLRP3 (for NACHT, LRR, and PYD domains-containing protein 3) forms a macromolecular structure called the NLRP3 inflammasome. The NLRP3 inflammasome plays a major role in inflammation, particularly in the production of IL (interleukin)-1β. IL-1β is the most studied of the IL-1 family of cytokines, including 11 members, among which are IL-1α and IL-18. Here, we summarize preclinical and clinical findings supporting the key pathogenetic role of the NLRP3 inflammasome and IL-1 cytokines in the formation, progression, and complications of atherosclerosis, in ischemic (acute myocardial infarction), and nonischemic injury to the myocardium (myocarditis) and the progression to heart failure. We also review the clinically available IL-1 inhibitors, although not currently approved for cardiovascular indications, and discuss other IL-1 inhibitors, not currently approved, as well as oral NLRP3 inflammasome inhibitors currently in clinical development. Canakinumab, IL-1β antibody, prevented the recurrence of ischemic events in patients with prior acute myocardial infarction in a large phase III clinical trial, including 10 061 patients world-wide. Phase II clinical trials show promising data with anakinra, recombinant IL-1 receptor antagonist, in patients with ST-segment-elevation acute myocardial infarction or heart failure with reduced ejection fraction. Anakinra also improved outcomes in patients with pericarditis, and it is now considered standard of care as second-line treatment for patients with recurrent/refractory pericarditis. Rilonacept, a soluble IL-1 receptor chimeric fusion protein neutralizing IL-1α and IL-1β, has also shown promising results in a phase II study in recurrent/refractory pericarditis. In conclusion, there is overwhelming evidence linking the NLRP3 inflammasome and the IL-1 cytokines with the pathogenesis of cardiovascular diseases. The future will likely include targeted inhibitors to block the IL-1 isoforms, and possibly oral NLRP3 inflammasome inhibitors, across a wide spectrum of cardiovascular diseases.

Imbalance Between Interleukin-1β and Interleukin-1 Receptor Antagonist in Epicardial Adipose Tissue Is Associated With Non ST-Segment Elevation Acute Coronary Syndrome

Introduction

Interleukin-1beta (IL-1β) is crucially involved in the pathogenesis of coronary atherosclerotic diseases (CAD) and its inhibition has proven cardiovascular benefits. Epicardial adipose tissue (EAT) is a local source of inflammatory mediators which may negatively affect the surrounding coronary arteries. In the present study, we explored the relationship between serum and EAT levels of IL-1β and IL-1 receptor antagonist (IL-1ra) in patients with chronic coronary syndrome (CCS) and recent acute coronary syndrome (ACS).

Methods

We obtained EAT biopsies in 54 CCS (Group 1) and 33 ACS (Group 2) patients undergoing coronary artery bypass grafting. Serum and EAT levels of IL-1β and IL-1ra were measured in all patients. An immunophenotypic study was carried out on EAT biopsies and the CD86 events were studied as markers of M1 macrophages.

Results

Circulating levels of IL-1β were significantly higher in the overall CAD population compared to a control group [7.64 pg/ml (6.86; 8.57) vs. 1.89 pg/ml (1.81; 2.29); p < 0.001]. In contrast, no differences were observed for serum IL-1ra levels between CAD and controls. Comparable levels of serum IL-1β were found between Groups 1 and 2 [7.6 pg/ml (6.9; 8.7) vs. 7.9 pg/ml (7.2; 8.6); p = 0.618]. In contrast, significantly lower levels of serum IL-1ra were found in Group 2 compared to Group 1 [274 pg/ml (220; 577) vs. 603 pg/ml (334; 1022); p = 0.035]. No differences of EAT levels of IL-1β were found between Group 2 and Group 1 [3.4 pg/ml (2.3; 8.4) vs. 2.4 pg/ml (1.9; 8.0); p = 0.176]. In contrast, significantly lower EAT levels of IL-1ra were found in Group 2 compared to Group 1 [101 pg/ml (40; 577) vs. 1344 pg/ml (155; 5327); p = 0.002]. No correlation was found between EAT levels of IL-1β and CD86 and CD64 events.

Conclusion

The present study explores the levels of IL-1β and IL-1ra in the serum and in EAT of CCS and ACS patients. ACS seems to be associated to a loss of the counter-regulatory activity of IL-1ra against the pro-inflammatory effects related to IL-1β activation.

Anakinra for corticosteroid-dependent and colchicine-resistant pericarditis: The IRAP (International Registry of Anakinra for Pericarditis) study

Aims

Novel therapies are needed for recurrent pericarditis, particularly when corticosteroid dependent and colchicine resistant. Based on limited data, interleukin-1 blockade with anakinra may be beneficial. The aim of this multicentre registry was to evaluate the broader effectiveness and safety of anakinra in a ‘real world’ population.

Methods and results

This registry enrolled consecutive patients with recurrent pericarditis who were corticosteroid dependent and colchicine resistant and treated with anakinra. The primary outcome was the pericarditis recurrence rate after treatment. Secondary outcomes included emergency department visits, hospitalisations, corticosteroid use and adverse events. Among 224 patients (46 ± 14 years old, 63% women, 75% idiopathic), the median duration of disease was 17 months (interquartile range 9–33). Most patients had elevated C-reactive protein (91%) and pericardial effusion (88%). After a median treatment of 6 months (3–12), pericarditis recurrences were reduced six-fold (2.33–0.39 per patient per year), emergency department admissions were reduced 11-fold (1.08–0.10 per patient per year), hospitalisations were reduced seven-fold (0.99–0.13 per patient per year). Corticosteroid use was decreased by anakinra (respectively from 80% to 27%; P < 0.001). No serious adverse events occurred; adverse events consisted mostly of transient skin reactions (38%) at the injection site. Adverse events led to discontinuation in 3%. A full-dose treatment duration of over 3 months followed by a tapering period of over 3 months were the therapeutic schemes associated with a lower risk of recurrence.

Conclusion

In patients with recurrent pericarditis, anakinra appears efficacious and safe in reducing recurrences, emergency department admissions and hospitalisations.

Cardiogenic Pulmonary Edema

The initial events in cardiogenic pulmonary edema involve hemodynamic pulmonary congestion with high capillary pressures. This causes increased fluid transfer out of capillaries into the interstitium and alveolar spaces. High capillary pressures can also cause barrier disruption which increases permeability and fluid transfer into the interstitium and alveoli. Fluid in alveoli alters surfactant function and increases surface tension. This can lead to more edema formation and to atelectasis with impaired gas exchange. Patients with barrier disruption have increased levels of surfactant protein B in the circulation, and these levels often remain high after the initial clinical improvement. Routine clinical assessment may not identify patients with increased extravascular fluid in the lungs; pulmonary ultrasound can easily detect pulmonary edema in patients with acute decompensation and in patients at risk for decompensation. Studies using serial pulmonary ultrasound could help characterize patients with cardiogenic pulmonary edema and help identify subgroups who need alternative management. The conventional management of cardiogenic pulmonary edema usually involves diuresis, afterload reduction and in some cases noninvasive ventilation to reduce the work of breathing and improve oxygenation. Patients with persistent symptoms, abnormal chest x-rays and diuretic resistance might benefit from alternative approaches to management. These could include beta agonists and pentoxifylline which warrant more study in patients with cardiogenic pulmonary edema.

IL-1 Blockade in Patients With Heart Failure With Preserved Ejection Fraction

Background Enhanced inflammation may lead to exercise intolerance in heart failure with preserved ejection fraction. The aim of the current study was to determine whether IL (interleukin)-1 blockade with anakinra improved cardiorespiratory fitness in heart failure with preserved ejection fraction. Methods and Results Thirty-one patients with heart failure with preserved ejection fraction and CRP (C-reactive protein) >2 mg/L were randomized to anakinra (100 mg subcutaneously daily, N=21) or placebo (N=10) for 12 weeks. We measured peak oxygen consumption (Vo₂), ventilatory efficiency (V_E/Vco₂ slope), and high-sensitivity CRP and NT-proBNP (N-terminal pro-B-type natriuretic peptide) at 4, 12, and 24 weeks. Twenty-eight patients completed ≥2 visits, 18 women (64%), 27 (96%) obese. There were no differences in peak Vo₂ or V_E/Vco₂ slope between groups at baseline. Peak Vo₂ was not changed after 12 weeks of anakinra (from 13.6 [11.8-18.0] to 14.2 [11.2-18.5] mL·kg^-1·min^-1, P=0.89), or placebo (14.9 [11.7-17.2] to 15.0 [13.8-16.9] mL·kg^-1·min^-1, P=0.40), without significant between-group differences in changes at 12 weeks (-0.4 [95% CI, -2.2 to +1.4], P=0.64). V_E/Vco₂ slope was also unchanged with anakinra (from 28.3 [27.2-33.0] to 30.5 [26.3-32.8], P=0.97) or placebo (from 31.6 [27.3-36.9] to 31.2 [27.8-33.4], P=0.78), without significant between-group differences in changes at 12 weeks (+1.2 [95% CI, -1.8 to +4.3], P=0.97). Within the anakinra-treated patients, high-sensitivity CRP and NT-proBNP levels were lower at 4 weeks compared with baseline ( P=0.026 and P=0.022 versus placebo [between-group analysis], respectively). Conclusions Treatment with anakinra for 12 weeks failed to improve peak Vo₂ and V_E/Vco₂ slope in a group of obese heart failure with preserved ejection fraction patients. The favorable trends in high-sensitivity CRP and NT-proBNP with anakinra deserve exploration in future studies. Clinical Trial Registration URL: https://www.clinicaltrials.gov . Unique identifier: NCT02173548.

NLRP3 inhibition improves heart function in GPER knockout mice

The molecular mechanisms of postmenopausal heart diseases in women may involve the loss of estrogen-deactivation of its membrane receptor, G-protein coupled estrogen receptor (GPER), and subsequent activation of the cardiac NLRP3 inflammasome, a component of the innate immune system. To study the potential effects of cardiac GPER on NLRP3-mediated inflammatory pathways, we characterized changes in innate immunity gene transcripts in hearts from 6-month-old cardiomyocyte-specific GPER knockout (KO) mice and their GPER-intact wild type (WT) littermates using RT² Profiler™ real-time PCR array. GPER deletion in cardiomyocytes decreased %fractional shortening (%FS) and myocardial relaxation (e'), and increased the early mitral inflow filling velocity-to-early mitral annular descent velocity ratio (E/e'), determined by echocardiography, and increased the mRNA levels of atrial natriuretic factor (ANF) and brain natriuretic peptide (BNP), determined by real-time PCR. Of the 84 inflammasome-related genes tested, 9 genes were upregulated, including NLRP3 and IL-18, while 1 gene, IL-12a, was downregulated in GPER KO when compared to WT. The importance of NLRP3 upregulation in GPER KO-induced heart failure was further confirmed by an in vivo study showing that, compared to vehicle-treated KO mice, 8 weeks of treatment with a NLRP3 inhibitor, MCC950 (10 mg/kg, i.p., 3 times per week), significantly limited hypertrophic remodeling, defined by reductions in heart weight/body weight, and improved systolic and diastolic functional indices, including increases in %FS and e', and decreases E/e' (P < 0.05). Both ANF and BNP mRNA levels were also significantly reduced by chronic MCC950 treatment. The findings from this study point toward a new understanding for the increased occurrence of heart diseases in women following loss or absence of estrogenic protection and GPER activation that involves cardiac NLRP3 inflammatory pathways.

C-Reactive Protein and N-Terminal Pro-brain Natriuretic Peptide Levels Correlate With Impaired Cardiorespiratory Fitness in Patients With Heart Failure Across a Wide Range of Ejection Fraction

Background: Impaired cardiorespiratory fitness (CRF) is a hallmark of heart failure (HF). Serum levels of C-reactive protein (CRP), a systemic inflammatory marker, and of N-terminal pro-brain natriuretic peptide (NT-proBNP), a biomarker of myocardial strain, independently predict adverse outcomes in HF patients. Whether CRP and/or NT-proBNP also predict the degree of CRF impairment in HF patients across a wide range of ejection fraction is not yet established.

Methods: Using retrospective analysis, 200 patients with symptomatic HF who completed one or more treadmill cardiopulmonary exercise tests (CPX) using a symptom-limited ramp protocol and had paired measurements of serum high-sensitivity CRP and NT-proBNP on the same day were evaluated. Univariate and multivariate correlations were evaluated with linear regression after logarithmic transformation of CRP (log₁₀) and NT-proBNP (log_N).

Results: Mean age of patients was 57 ± 10 years and 55% were male. Median CRP levels were 3.7 [1.5–9.0] mg/L, and NT-proBNP levels were 377 [106–1,464] pg/ml, respectively. Mean peak oxygen consumption (peak VO₂) was 16 ± 4 mlO₂•kg⁻¹•min⁻¹. CRP levels significantly correlated with peakVO₂ in all patients (R = −0.350, p < 0.001) and also separately in the subgroup of patients with reduced left ventricular ejection fraction (LVEF) (HFrEF, N = 109) (R = −0.282, p < 0.001) and in those with preserved EF (HFpEF, N = 57) (R = −0.459, p < 0.001). NT-proBNP levels also significantly correlated with peak VO₂ in all patients (R = −0.330, p < 0.001) and separately in patients with HFrEF (R = −0.342, p < 0.001) and HFpEF (R = −0.275, p = 0.032). CRP and NT-proBNP did not correlate with each other (R = 0.05, p = 0.426), but independently predicted peak VO₂ (R = 0.421, p < 0.001 and p < 0.001, respectively).

Conclusions: Biomarkers of inflammation and myocardial strain independently predict peak VO₂ in HF patients. Anti-inflammatory therapies and therapies alleviating myocardial strain may independently improve CRF in HF patients across a large spectrum of LVEF.