Innate immunity and the failing heart: the cytokine hypothesis revisited

Metagenomic and metabolomic analyses unveil dysbiosis of gut microbiota in chronic heart failure patients

Previous studies suggested a possible gut microbiota dysbiosis in chronic heart failure (CHF). However, direct evidence was lacking. In this study, we investigated the composition and metabolic patterns of gut microbiota in CHF patients to provide direct evidence and comprehensive understanding of gut microbiota dysbiosis in CHF. We enrolled 53 CHF patients and 41 controls. Metagenomic analyses of faecal samples and metabolomic analyses of faecal and plasma samples were then performed. We found that the composition of gut microbiota in CHF was significantly different from controls. Faecalibacterium prausnitzii decrease and Ruminococcus gnavus increase were the essential characteristics in CHF patients' gut microbiota. We also observed an imbalance of gut microbes involved in the metabolism of protective metabolites such as butyrate and harmful metabolites such as trimethylamine N-oxide in CHF patients. Metabolic features of both faecal and plasma samples from CHF patients also significantly changed. Moreover, alterations in faecal and plasma metabolic patterns correlated with gut microbiota dysbiosis in CHF. Taken together, we found that CHF was associated with distinct gut microbiota dysbiosis and pinpointed the specific core bacteria imbalance in CHF, along with correlations between changes in certain metabolites and gut microbes.

New Insights into the Immunobiology of Mononuclear Phagocytic Cells and Their Relevance to the Pathogenesis of Cardiovascular Diseases

Macrophages are the primary immune cells that reside within the myocardium, suggesting that these mononuclear phagocytes are essential in the orchestration of cardiac immunity and homeostasis. Independent of the nature of the injury, the heart triggers leukocyte activation and recruitment. However, inflammation is harmful to this vital terminally differentiated organ with extremely poor regenerative capacity. As such, cardiac tissue has evolved particular strategies to increase the stress tolerance and minimize the impact of inflammation. In this sense, growing evidences show that mononuclear phagocytic cells are particularly dynamic during cardiac inflammation or infection and would actively participate in tissue repair and functional recovery. They respond to soluble mediators such as metabolites or cytokines, which play central roles in the timing of the intrinsic cardiac stress response. During myocardial infarction two distinct phases of monocyte influx have been identified. Upon infarction, the heart modulates its chemokine expression profile that sequentially and actively recruits inflammatory monocytes, first, and healing monocytes, later. In the same way, a sudden switch from inflammatory macrophages (with microbicidal effectors) toward anti-inflammatory macrophages occurs within the myocardium very shortly after infection with Trypanosoma cruzi, the causal agent of Chagas cardiomyopathy. While in sterile injury, healing response is necessary to stop tissue damage; during an intracellular infection, the anti-inflammatory milieu in infected hearts would promote microbial persistence. The balance of mononuclear phagocytic cells seems to be also dynamic in atherosclerosis influencing plaque initiation and fate. This review summarizes the participation of mononuclear phagocyte system in cardiovascular diseases, keeping in mind that the immune system evolved to promote the reestablishment of tissue homeostasis following infection/injury, and that the effects of different mediators could modulate the magnitude and quality of the immune response. The knowledge of the effects triggered by diverse mediators would serve to identify new therapeutic targets in different cardiovascular pathologies.

Limited Added Value of Circulating Inflammatory Biomarkers in Chronic Heart Failure

OBJECTIVES

This study sought to evaluate whether a panel of biomarkers improved prognostication in patients with heart failure (HF) and reduced ejection fraction of ischemic origin using a systematized approach according to suggested requirements for validation of new biomarkers.

BACKGROUND

Modeling combinations of multiple circulating markers could potentially identify patients with HF at particularly high risk and aid in the selection of individualized therapy.

METHODS

From a panel of 20 inflammatory and extracellular matrix biomarkers, 2 different biomarker panels were created and added to the Seattle HF score and the prognostic model from the CORONA (Controlled Rosuvastatin Multinational Trial in Heart Failure) study (n = 1,497), which included conventional clinical characteristics and C-reactive protein and N-terminal pro-B-type natriuretic peptide. Interactions with statin treatment were also assessed.

RESULTS

The two models-model 1 (endostatin, interleukin 8, soluble ST2, troponin T, galectin 3, and chemokine [C-C motif] ligand 21) and model 2 (troponin T, soluble ST2, galectin 3, pentraxin 3, and soluble tumor necrosis factor receptor 2)-significantly improved the CORONA and Seattle HF models but added only modestly to their Harrell's C statistic and net reclassification index. In addition, rosuvastatin had no effect on the levels of a wide range of inflammatory and extracellular matrix markers, but there was a tendency for patients with a lower level of biomarkers in the 2 panels to have a positive effect from statin treatment.

CONCLUSIONS

In the specific HF patient population studied, a multimarker approach using the particular panel of biomarkers measured was of limited clinical value for identifying future risk of adverse outcomes.

Soluble Urokinase-Type Plasminogen Activator Receptor Improves Risk Prediction in Patients With Chronic Heart Failure

OBJECTIVES

This study investigated the predictive value of soluble urokinase-type plasminogen activator receptor (suPAR) in patients with chronic heart failure (CHF).

BACKGROUND

SuPAR originates from proteolytic cleavage of the membrane-bound receptor from activated immune and endothelial cells and reflects the level of immune activation. As inflammation plays a crucial role in the complex pathophysiology of CHF, we hypothesized that suPAR might be a suitable prognostic biomarker in patients with CHF.

METHODS

SuPAR levels were determined in 319 patients with CHF admitted to our outpatient department for heart failure and in a second cohort consisting of 346 patients with CHF, for validation.

RESULTS

During a median follow-up time of 3.2 years, 119 patients (37.3%) died. SuPAR was a strong predictor of mortality with a crude hazard ratio (HR) per increase of 1 SD (HR per 1 SD) of 1.96 (95% confidence interval [CI]: 1.63 to 2.35; p < 0.001) in univariate analysis and remained significant after comprehensive multivariate adjustment with an adjusted HR per 1 SD of 1.38 (95% CI: 1.04 to 1.83; p = 0.026). SuPAR added prognostic value beyond the multivariate model indicated by improvements in C-statistics (area under the curve: 0.72 vs 0.74, respectively; p = 0.02), the category-free net reclassification index (24.9%; p = 0.032), and the integrated discrimination improvement (0.011; p = 0.05). Validation in the second cohort yielded consistent results.

CONCLUSIONS

SuPAR is a strong and independent predictor of mortality in patients with CHF, potentially suitable to refine risk assessment in this vulnerable group of patients. Our results emphasize the impact of immune activation on survival in patients with CHF.

HIF-1, Metabolism, and Diabetes in the Embryonic and Adult Heart

The heart is able to metabolize any substrate, depending on its availability, to satisfy its energy requirements. Under normal physiological conditions, about 95% of ATP is produced by oxidative phosphorylation and the rest by glycolysis. Cardiac metabolism undergoes reprograming in response to a variety of physiological and pathophysiological conditions. Hypoxia-inducible factor 1 (HIF-1) mediates the metabolic adaptation to hypoxia and ischemia, including the transition from oxidative to glycolytic metabolism. During embryonic development, HIF-1 protects the embryo from intrauterine hypoxia, its deletion as well as its forced expression are embryonically lethal. A decrease in HIF-1 activity is crucial during perinatal remodeling when the heart switches from anaerobic to aerobic metabolism. In the adult heart, HIF-1 protects against hypoxia, although its deletion in cardiomyocytes affects heart function even under normoxic conditions. Diabetes impairs HIF-1 activation and thus, compromises HIF-1 mediated responses under oxygen-limited conditions. Compromised HIF-1 signaling may contribute to the teratogenicity of maternal diabetes and diabetic cardiomyopathy in adults. In this review, we discuss the function of HIF-1 in the heart throughout development into adulthood, as well as the deregulation of HIF-1 signaling in diabetes and its effects on the embryonic and adult heart.

Deficiency of NOD1 Improves the β-Adrenergic Modulation of Ca2+ Handling in a Mouse Model of Heart Failure

Heart failure (HF) is a complex syndrome characterized by cardiac dysfunction, Ca²⁺ mishandling, and chronic activation of the innate immune system. Reduced cardiac output in HF leads to compensatory mechanisms via activation of the adrenergic nervous system. In turn, chronic adrenergic overstimulation induces pro-arrhythmic events, increasing the rate of sudden death in failing patients. Nucleotide-binding oligomerization domain-containing protein 1 (NOD1) is an innate immune modulator that plays a key role in HF progression. NOD1 deficiency in mice prevents Ca²⁺ mishandling in HF under basal conditions, but its role during β-adrenergic stimulation remains unknown. Here, we evaluated whether NOD1 regulates the β-adrenergic modulation of Ca²⁺ signaling in HF. Ca²⁺ dynamics were examined before and after isoproterenol perfusion in cardiomyocytes isolated from healthy and from post-myocardial infarction (PMI) wild-type (WT) and Nod1^-/- mice. Isoproterenol administration induced similar effects on intracellular [Ca²⁺]_i transients, cell contraction, and sarcoplasmic reticulum (SR)-Ca²⁺ load in healthy WT and Nod1^-/- cells. However, compared with WT-PMI cells, isoproterenol exposure induced a significant increase in the [Ca²⁺]_i transients and cell contraction parameters in Nod1^-/--PMI cells, which mainly due to an increase in SR-Ca²⁺ load. NOD1 deficiency also prevented the increase in diastolic Ca²⁺ leak (Ca²⁺ waves) induced by isoproterenol in PMI cells. mRNA levels of β1 and β2 adrenergic receptors were significantly higher in Nod1^-/--PMI hearts vs WT-PMI hearts. Healthy cardiomyocytes pre-treated with the selective agonist of NOD1, iE-DAP, and perfused with isoproterenol showed diminished [Ca²⁺]_i transients amplitude, cell contraction, and SR-Ca²⁺ load compared with vehicle-treated cells. iE-DAP-treated cells also presented increased diastolic Ca²⁺ leak under β-adrenergic stimulation. The selectivity of iE-DAP on Ca²⁺ handling was validated by pre-treatment with the inactive analog of NOD1, iE-Lys. Overall, our data establish that NOD1 deficiency improves the β-adrenergic modulation of Ca²⁺ handling in failing hearts.

Rheumatoid Arthritis: A Brief Overview of the Treatment

Rheumatoid arthritis (RA) is a chronic, inflammatory, systemic autoimmune disease, affecting the joints with varying severity among patients. The risk factors include age, gender, genetics, and environmental exposure (cigarette smoking, air pollutants, and occupational). Many complications can follow, such as permanent joint damage requiring arthroplasty, rheumatoid vasculitis, and Felty syndrome requiring splenectomy if it remains unaddressed. As there is no cure for RA, the treatment goals are to reduce the pain and stop/slow further damage. Here, we present a brief summary of various past and present treatment modalities to address the complications associated with RA.

THE CARDIOSPLENIC AXIS IS ESSENTIAL FOR THE PATHOGENESIS OF ISCHEMIC HEART FAILURE

The role of innate and adaptive immunity in heart failure (HF) is poorly understood. We discovered that mice with ischemic HF exhibit robust expansion of proinflammatory monocytes/macrophages, classical and plasmacytoid dendritic cells, and CD4⁺ and CD8⁺ T cells. There was profound splenic remodeling indicative of heightened antigen processing, and expanded antigen-experienced effector and memory CD4⁺ T cell populations. A series of subsequent studies in HF mice that incorporated splenectomy, adoptive transfer of both unselected splenocytes and splenic CD4⁺ T-cells, and antibody-mediated CD4⁺ T-cell depletion indicated that intensely activated splenic immune cells: 1) underlie the chronic inflammatory response in HF, 2) traffic and home to the failing heart, and 3) exhibit immune memory and are primed to induce tissue injury that promotes pathological cardiac remodeling. Hence, we propose that ischemic cardiomyopathy is in part an immune-mediated disease, against as-of-yet unidentified cardiac antigens, with a central role for the spleen in this process.

Hemographic indices are associated with mortality in acute heart failure

Hemographic indices have been associated with clinical outcomes in patients with chronic heart failure. We therefore investigated the prognostic values of hemographic indices in patients hospitalized for acute heart failure (AHF). Patients hospitalized primarily for AHF were drawn from an intramural registry. Hemographic indices, including white blood cell counts, neutrophil counts, neutrophil-to-lymphocyte ratio, reciprocal of lymphocyte (RL) and platelet-to-lymphocyte ratio were recorded. Among a total of 1923 participants (mean age 76 ± 12 years, 68% men), 875 patients died during a mean follow-up of 28.6 ± 20.7 months. Except for white blood cell counts, all the other hemographic indices were related to mortality, independently. In a forward stepwise Cox regression analysis among hemographic indices, RL was the strongest predictor (HR and 95% CI per-1SD:1.166,1.097-1.240) for mortality, after accounting for confounders. However, conditioned on the survivals, the hemographic indices were independently related to mortality within 3 years of follow-up, rather than beyond. Hemographic indices were independent risk factors of mortality in patients hospitalized for AHF, especially in patients with impaired left ventricular systolic function. As an acute presentation of inflammation, hemographic indices might be useful to identify subjects at risk of mortality soon after the index hospitalization.

Immunotherapy for cardiovascular disease

Heart failure (HF), the final stage of pathological cardiac hypertrophy, is a major cause of hospitalization and mortality. The role of inflammation in the pathogenesis of HF has been extensively studied, with great emphasis on proinflammatory cytokines. Yet, clinical trials targeting these cytokines failed to become a credible therapeutic strategy for HF. More recent studies are increasingly highlighting an active role for T cells in the progression of HF pathology. As a result, a number of novel immunotherapy strategies are emerging for the treatment of HF and other cardiovascular diseases, via the targeting of adaptive immunity. Here we provide an overview of the background, details, and expected outcomes of these attempts.

ASC Methylation and Interleukin-1β Are Associated with Aerobic Capacity in Heart Failure

BACKGROUND

Aerobic capacity, as measured by peak oxygen uptake (V˙O2), is one of the most powerful predictors of prognosis in heart failure (HF). Inflammation is a key factor contributing to alterations in aerobic capacity, and interleukin (IL)-1 cytokines are implicated in this process. The adaptor protein ASC is necessary for inflammasome activation of IL-1β and IL-18. ASC expression is controlled through epigenetic modification; lower ASC methylation is associated with worse outcomes in HF. The purpose of this study is to examine the relationships between ASC methylation, IL-1β, and IL-18 with V˙O2peak in persons with HF.

METHODS

This study examined the relationship between ASC methylation, IL-1β, and IL-18 with V˙O2peak in 54 stable outpatients with HF. All participants were NYHA class II or III, not engaged in an exercise program, and physically able to complete an exercise treadmill test.

RESULTS

Mean V˙O2peak was 16.68 ± 4.7 mL·kg·min. V˙O2peak was positively associated with mean percent ASC methylation (r = 0.47, P = 0.001) and negatively associated with IL-1β (r = -0.38, P = 0.007). Multiple linear regression models demonstrated that V˙O2peak increased by 2.30 mL·kg·min for every 1% increase in ASC methylation and decreased by 1.91 mL·kg·min for every 1 pg·mL increase in plasma IL-1β.

CONCLUSIONS

Mean percent ASC methylation and plasma IL-1β levels are associated with clinically meaningful differences in V˙O2peak in persons with HF. Inflammasome activation may play a mechanistic role in determining aerobic capacity. ASC methylation is a potentially modifiable mechanism for reducing the inflammatory response, thereby improving aerobic capacity in HF.

Where Does Inflammation Fit?

PURPOSE OF REVIEW

This review focuses on the complex relationship between inflammation and the onset of acute coronary syndrome and heart failure.

RECENT FINDINGS

In the last few years, two important lines of research brought new and essential information to light in the pathogenesis of acute coronary syndrome: a) the understanding of the immune mediate mechanisms of inflammation in Ischemic Heart Disease (IHD) and b) evidence that the inflammatory mechanisms associated with atherosclerosis and its complications can be modulated by anti-inflammatory molecules. A large amount of data also suggests that inflammation is a major component in the development and exacerbation of heart failure (HF), in a symbiotic relationship. In particular, recent evidence underlies peculiar aspects of the phenomenon: oxidative stress and autophagy; DAMPS and TLR-4 signaling activation; different macrophages lineage and the contribution of NLRP-3 inflammasome; adaptive immune system. A possible explanation that could unify the pathogenic mechanism of these different conditions is the rising evidence that increased bowel permeability may allow translation of gut microbioma product into the circulation. These findings clearly establish the role of inflammation as the great trigger for two of the major cardiovascular causes of death and morbidity. Further studies are needed, to better clarify the issue and to define more targeted approaches to reduce pathological inflammation while preserving the physiological one.

BEX1 is an RNA-dependent mediator of cardiomyopathy

Regulation of mRNA splicing, processing and stability is increasingly recognized as a critical control point in dynamically altering gene expression during stress or disease. Very little is understood of this process in heart failure. Here, we show that BEX1 is a heart failure-induced gene functioning as an mRNA-associated protein that enhances expression of a subset of cardiac disease-promoting genes. Modeling the increase in BEX1 that occurs in disease, cardiac-specific BEX1 transgenic mice show worse cardiac disease with stress stimulation, whereas Bex1 gene-deleted mice are protected from heart failure-promoting insults. Proteomic and interactive screening assays show that BEX1 is part of a large ribonucleoprotein processing complex involved in regulating proinflammatory mRNA expression in the heart. Specifically, induction of BEX1 augments the stability and expression of AU-rich element containing mRNAs typically found within proinflammatory genes. Thus, BEX1 functions as an mRNA-dependent effector that augments pathology-promoting gene expression during heart failure.

Little is known about the changes in mRNA splicing, processing and stability that can alter gene expression during heart failure. Here, the authors show that BEX1 is induced during heart failure and is part of a ribonucleoprotein complex enhancing the expression and stability of proinflammatory genes.

Value of soluble Urokinase plasminogen activator receptor over age as a biomarker of impaired myocardial relaxation

Background

SuPAR is a biomarker that reflects the level of immune activation. As inflammation plays an important role in the ageing process of the cardiovascular system, we hypothesized that suPAR might be a useful predictive biomarker of the ageing heart.

Methods

We performed conventional and tissue Doppler echocardiography and measured plasma suPAR levels.

Results

We studied community adults (n=120, 37.5% female) (mean age: 70.3±9.3 years) without known cardiovascular disease (CVD). Participants with impaired myocardial relaxation were older (84% vs 59% were aged ≥71 years, p=0.002), with more diabetes mellitus (27% vs 11%, p=0.034). SuPAR levels were higher among participants with impaired myocardial relaxation (3.9 ng/ml vs 3.0 ng/ml, p=0.015). At the univariate level, older age (OR 3.6; 95%CI 1.6, 8.5; p=0.003), diabetes mellitus (OR 3.04; 95%CI 1.1, 8.8; p=0.04), systolic blood pressure (OR 1.03; 95%CI 1.001, 1.1; p=0.041) and suPAR levels ≥3.00ng/ml (OR 3.4; 95%CI 1.16, 7.4; p=0.002) were associated with impaired myocardial relaxation. In multivariable regression analysis, only older age (OR 2.8; 95%CI 1.1, 6.7; p=0.026) and suPAR (OR 2.7; 95%CI 1.2, 6.1; p=0.018) remained independently associated with impaired myocardial relaxation. Receiver operating characteristics (ROC) curve analysis revealed an area under the curve (AUC) value of 0.63 (95% CI 0.54, 0.71) for model that included age alone. Addition of suPAR significantly increased AUC value to 0.70 (95%CI 0.60, 0.79), which was significantly larger than the model with age alone (p=0.016).

Conclusion

We demonstrate additional ability of suPAR, over age, to predict impaired myocardial relaxation.

Trial registration

ClinicalTrials.gov Identifier: NCT02791139 (Registered May 31, 2016).

T helper cells with specificity for an antigen in cardiomyocytes promote pressure overload-induced progression from hypertrophy to heart failure

We investigated whether CD4⁺-T cells with specificity for an antigen in cardiomyocytes promote the progression from hypertrophy to heart failure in mice with increased pressure load due to transverse aortic constriction (TAC). OT-II mice expressing a transgenic T cell receptor (TCR) with specificity for ovalbumin (OVA) on CD4⁺-T cells and cMy-mOVA mice expressing OVA on cardiomyocytes were crossed. The resulting cMy-mOVA-OT-II mice did not display signs of spontaneous autoimmunity despite the fact that their OVA-specific CD4⁺-T cells were not anergic. After TAC, progression to heart failure was significantly accelerated in cMy-mOVA-OT-II compared to cMy-mOVA mice. No OVA-specific antibodies were induced in response to TAC in cMy-mOVA-OT-II mice, yet more CD3⁺ T cells infiltrated their myocardium when compared with TAC-operated cMy-mOVA mice. Systemically, the proportion of activated CD4⁺-T cells with a Th₁ and Th₁₇ cytokine profile was increased in cMy-mOVA-OT-II mice after TAC. Thus, T helper cells with specificity for an antigen in cardiomyocytes can directly promote the progression of heart failure in response to pressure overload independently of autoantibodies.

IRF3 and type I interferons fuel a fatal response to myocardial infarction

Interferon regulatory factor 3 (IRF3) and type I interferons (IFNs) protect against infections¹ and cancer², but excessive IRF3 activation and type I IFN production cause auto-inflammatory conditions such as Aicardi Goutieres Syndrome^3,4 and STING-associated vasculopathy of infancy (SAVI)³. Myocardial infarction (MI) elicits inflammation⁵, but the dominant molecular drivers of MI-associated inflammation remain unclear. Here, we show that ischemic cell death in the heart fuels a fatal response to myocardial infarction by activating IRF3 and type I IFN production. In mice, single cell RNA-Seq analysis of 4,215 leukocytes isolated from infarcted and non-infarcted hearts revealed that MI provokes activation of an IRF3-interferon axis in a distinct population of interferon inducible cells (IFNICs that were classified as cardiac macrophages). Mice genetically deficient in cGAS, its adaptor STING, IRF3, or the type I interferon receptor IFNAR exhibited impaired interferon stimulated gene (ISG) expression and, in the case of mice deficient in IRF3 or IFNAR, improved survival after MI as compared to controls. Interruption of IRF3-dependent signaling resulted in decreased cardiac expression of inflammatory cytokines and chemokines and decreased cardiac inflammatory cell infiltration, as well as in attenuated ventricular dilation and improved cardiac function. Similarly, treatment of mice with an IFNAR neutralizing antibody after MI ablated the IFN response and improved left ventricular dysfunction and survival. These results identify IRF3 and the type I interferon response as a potential therapeutic target for post-MI cardioprotection.

The massive cell death that occurs during myocardial infarction releases self-DNA and triggers an interferon response in infiltrating leukocytes via a cGAS-STING-IRF3 pathway. In mice subjected to myocardial infarction, genetic disrupton of this pathway or antibody blockade of the type I interferon receptor improved heart function and survival.

The role of the blood-brain barrier in hypertension

NEW FINDINGS

What is the topic of this review? This review highlights the importance of the blood-brain barrier in the context of diseases involving autonomic dysfunction, such as hypertension and heart failure. What advances does it highlight? It highlights the potential role of pro-inflammatory cytokines, leucocytes and angiotensin II in disrupting the blood-brain barrier in cardiovascular diseases. Advances are highlighted in our understanding of neurovascular unit cells, astrocytes and microglia, with a specific emphasis on their pathogenic roles within the brain. The blood-brain barrier (BBB) is a crucial barrier that provides both metabolic and physical protection to an immune-privileged CNS. The BBB has been shown to be disrupted in hypertension. This review addresses the importance of the BBB in maintaining homeostasis in the context of diseases related to autonomic dysfunction, such as hypertension. We highlight the potentially important roles of the immune system and neurovascular unit in the maintenance of the BBB, whereby dysregulation may lead to autonomic dysfunction in diseases such as heart failure and hypertension. Circulating leucocytes and factors such as angiotensin II and pro-inflammatory cytokines are thought ultimately to downregulate endothelial tight junction proteins that are a crucial component of the BBB. The specific mechanisms underlying BBB disruption and their role in contributing to autonomic dysfunction are not yet fully understood but are a growing area of interest. A greater understanding of these systems and advances in our knowledge of the molecular mechanisms causing BBB disruption will allow for the development of future therapeutic interventions in the treatment of autonomic imbalance associated with diseases such as heart failure and hypertension.

The infarcted myocardium solicits GM-CSF for the detrimental oversupply of inflammatory leukocytes

Myocardial infarction elicits massive recruitment of monocytes and neutrophils to the myocardium, but the mechanisms that control these processes are not fully understood. Here, Anzai et al. show that GM-CSF is a powerful orchestrator contributing to monocyte and neutrophil production, recruitment, and function.

Myocardial infarction (MI) elicits massive inflammatory leukocyte recruitment to the heart. Here, we hypothesized that excessive leukocyte invasion leads to heart failure and death during acute myocardial ischemia. We found that shortly and transiently after onset of ischemia, human and mouse cardiac fibroblasts produce granulocyte/macrophage colony-stimulating factor (GM-CSF) that acts locally and distally to generate and recruit inflammatory and proteolytic cells. In the heart, fibroblast-derived GM-CSF alerts its neighboring myeloid cells to attract neutrophils and monocytes. The growth factor also reaches the bone marrow, where it stimulates a distinct myeloid-biased progenitor subset. Consequently, hearts of mice deficient in either GM-CSF or its receptor recruit fewer leukocytes and function relatively well, whereas mice producing GM-CSF can succumb from left ventricular rupture, a complication mitigated by anti–GM-CSF therapy. These results identify GM-CSF as both a key contributor to the pathogenesis of MI and a potential therapeutic target, bolstering the idea that GM-CSF is a major orchestrator of the leukocyte supply chain during inflammation.

An overview of the inflammatory signalling mechanisms in the myocardium underlying the development of diabetic cardiomyopathy

Heart failure is a highly morbid and mortal clinical condition that represents the last stage of most cardiovascular disorders. Diabetes is strongly associated with an increased incidence of heart failure and directly promotes cardiac hypertrophy, fibrosis, and apoptosis. These changes, in turn, contribute to the development of ventricular dysfunction. The clinical condition associated with the spectrum of cardiac abnormalities induced by diabetes is termed diabetic cardiomyopathy. Myocardial inflammation has recently emerged as a pathophysiological process contributing to cardiac hypertrophy, fibrosis, and dysfunction in cardiac diseases. Myocardial inflammation is also implicated in the development of diabetic cardiomyopathy. Several molecular mechanisms link diabetes to myocardial inflammation. The NF-κB signalling pathway and the renin-angiotensin-aldosterone system are strongly activated in the diabetic heart, thereby promoting myocardial inflammation. Advanced glycation end-products and damage-associated molecular pattern molecules also represent strong triggers for inflammation. The mediators resulting from this inflammatory process modulate specific intracellular signalling mechanisms in cardiac cells that promote the development of diabetic cardiomyopathy. This review article will provide an overview of the signalling molecular mechanisms linking diabetic cardiomyopathy to myocardial inflammation.

Recent Advances in Understanding and Managing Cardiomyopathy

Cardiomyopathy is a disease of the heart muscle leading to abnormal structure or function in the absence of coronary artery disease, hypertension, or valvular or congenital heart disease. Currently, cardiomyopathy is the leading diagnosis of heart transplant patients worldwide. Incorporation of next-generation sequencing strategies will likely revolutionize genetic testing in cardiomyopathy. The use of patient-specific pluripotent stem cell-derived cardiomyocytes for disease modeling and therapeutic testing has opened a new avenue for precision medicine in cardiomyopathy. Stem cell therapy, gene therapy, interfering RNA, and small molecules are actively being evaluated in clinical trials.

Acute Leukemia is Associated with Cardiac Alterations before Chemotherapy

BACKGROUND

Patients with acute leukemia (AL) have a higher rate of congestive heart failure than patients with other cancers. AL may predispose to cardiac dysfunction before chemotherapy because of high cytokine release or direct leukemic myocardial infiltration. The aims of this study were to evaluate whether AL is associated with abnormalities of myocardial structure and function before chemotherapy and to identify possible risk factors associated with these myocardial changes.

METHODS

Using an echocardiographic database, 76 patients with AL and 76 patients without cancer matched for age, gender, hypertension, and the presence of diabetes were retrospectively selected. Subsequently, to assess the effect of a nonhematologic malignancy, 28 women in each group were matched with women with breast cancer. Left ventricular (LV) mass, volumes, ejection fraction, and global longitudinal strain (GLS) were measured before chemotherapy.

RESULTS

The patients were predominantly male (63%), with a median age of 51 years, and had low prevalence of cardiovascular risk factors. Despite similar LV ejection fractions, patients with AL had higher LV mass and volumes and lower GLS (-19.3 ± 2.7% vs -20.9 ± 1.9%, P < .001) than patients without cancer. Similarly, GLS was lower in women with AL compared with women with breast cancer or without cancer. Among patients with AL, high body mass index, low LV ejection fraction, and a small number of circulating lymphocytes were all independently associated with low GLS.

CONCLUSIONS

Patients with AL had higher LV volumes and lower GLS than patients without cancer and lower GLS than patients with breast cancer, suggesting that AL by itself may be associated with these cardiac alterations.

Simvastatin Ameliorates Diabetic Cardiomyopathy by Attenuating Oxidative Stress and Inflammation in Rats

Simvastatin is a lipid-lowering agent used to treat hypercholesterolemia and to reduce the risk of heart disease. This study scrutinized the beneficial effects of simvastatin on experimental diabetic cardiomyopathy (DCM), pointing to the role of hyperglycemia-induced oxidative stress and inflammation. Diabetes was induced by intraperitoneal injection of streptozotocin and both control and diabetic rats received simvastatin for 90 days. Diabetic rats showed significant cardiac hypertrophy, body weight loss, hyperglycemia, and hyperlipidemia. Serum creatine kinase MB (CK-MB) and troponin I showed a significant increase in diabetic rats. Simvastatin significantly improved body weight, attenuated hyperglycemia and hyperlipidemia, and ameliorated CK-MB and troponin I. Simvastatin prevented histological alterations and deposition of collagen in the heart of diabetic animals. Lipid peroxidation and nitric oxide were increased in the heart of diabetic rats whereas antioxidant defenses were decreased. These alterations were significantly reversed by simvastatin. In addition, simvastatin decreased serum inflammatory mediators and expression of NF-κB in the diabetic heart. Cardiac caspase-3 was increased in the diabetic heart and decreased following treatment with simvastatin. In conclusion, our results suggest that simvastatin alleviates DCM by attenuating hyperglycemia/hyperlipidemia-induced oxidative stress, inflammation, and apoptosis.

Brain-Heart Interaction: Cardiac Complications After Stroke

Neurocardiology is an emerging specialty that addresses the interaction between the brain and the heart, that is, the effects of cardiac injury on the brain and the effects of brain injury on the heart. This review article focuses on cardiac dysfunction in the setting of stroke such as ischemic stroke, brain hemorrhage, and subarachnoid hemorrhage. The majority of post-stroke deaths are attributed to neurological damage, and cardiovascular complications are the second leading cause of post-stroke mortality. Accumulating clinical and experimental evidence suggests a causal relationship between brain damage and heart dysfunction. Thus, it is important to determine whether cardiac dysfunction is triggered by stroke, is an unrelated complication, or is the underlying cause of stroke. Stroke-induced cardiac damage may lead to fatality or potentially lifelong cardiac problems (such as heart failure), or to mild and recoverable damage such as neurogenic stress cardiomyopathy and Takotsubo cardiomyopathy. The role of location and lateralization of brain lesions after stroke in brain-heart interaction; clinical biomarkers and manifestations of cardiac complications; and underlying mechanisms of brain-heart interaction after stroke, such as the hypothalamic-pituitary-adrenal axis; catecholamine surge; sympathetic and parasympathetic regulation; microvesicles; microRNAs; gut microbiome, immunoresponse, and systemic inflammation, are discussed.

Resolution Agonist 15-epi-Lipoxin A4 Programs Early Activation of Resolving Phase in Post-Myocardial Infarction Healing

Following myocardial infarction (MI), overactive inflammation remodels the left ventricle (LV) leading to heart failure coinciding with reduced levels of 15-epi-Lipoxin A₄ (15-epi LXA₄). However, the role of 15-epi LXA₄ in post-MI acute inflammatory response and resolving phase is unclear. We hypothesize that liposomal fusion of 15-epi-LXA₄ (Lipo-15-epi-LXA₄) or free 15-epi-LXA₄ will expedite the resolving phase in post-MI inflammation. 8 to 12-week-old male C57BL/6 mice were subjected to permanent coronary artery ligation. Lipo-15-epi-LXA₄ or 15-epi-LXA₄ (1 µg/kg/day) was injected 3 hours post-MI for (d)1 or continued daily till d5. 15-epi-LXA₄ activated formyl peptide receptor (FPR2) and GPR120 on alternative macrophages but inhibited GPR40 on classical macrophages in-vitro. The 15-epi-LXA₄ injected mice displayed reduced LV and lung mass to body weight ratios and improved ejection fraction at d5 post-MI. In the acute phase of inflammation-(d1), 15-epi-LXA₄ primes neutrophil infiltration with a robust increase of Ccl2 and FPR2 expression. During the resolving phase-(d5), 15-epi-LXA₄ initiated rapid neutrophils clearance with persistent activation of FPR2 in LV. Compared to MI-control, 15-epi-LXA₄ injected mice showed reduced renal inflammation along with decreased levels of ngal and plasma creatinine. In summary, 15-epi-LXA₄ initiates the resolving phase early to discontinue inflammation post-MI, thereby reducing LV dysfunction.

Liraglutide ameliorates cardiotoxicity induced by doxorubicin in rats through the Akt/GSK-3β signaling pathway

Doxorubicin (Dox)-induced cardiotoxicity constitutes the major adverse effect that limited its use. We investigated the possible protective effects of liraglutide on Dox-induced cardiotoxicity in rats. Rats were divided into the following groups: control group rats received normal saline [1 ml/kg, intraperitoneal (i.p.)]; doxorubicin group rats received doxorubicin (1.25 mg/kg, i.p.), four times per week for 4 weeks; and liraglutide group rats received doxorubicin (1.25 mg/kg, i.p.) four times per week for 4 weeks then received liraglutide (100 μg/kg, i.p) daily for 4 weeks. At the end of the study, animals were sacrificed and serum creatine kinase-MB (CK-MB) and troponin I levels were determined. Malondialdehyde (MDA), superoxide dismutase (SOD), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and caspase-3 levels of the heart were determined. Cardiac AMPK, phosphorylated-Akt, tissue growth factor-β1 (TGF-β1), and GSK3-β levels of the heart were determined. Hematoxylin and eosin (H&E) stained sections form the heart were examined as well as immunohistochemical sections for detection of Bcl-2 expression. Dox treatment increased serum level of troponin I and CK-MB while decreased SOD activity, decreased AMPK, and p-Akt cardiac levels with increased in MDA, IL-6, TNF-α,GSK-3b, TGFB1, and caspase-3 levels in the heart with inflammation and necrosis in cardiac histopathology with decreased Bcl-2. Treatment with liraglutide decreased troponin I and CK-MB while increased SOD activity, AMPK, p-Akt with decrements in MDA, IL-6, TNF-α, GSK-3β, TGF-β1, and caspase-3 levels with attenuation of inflammation and necrosis while increased Bcl-2 expression. Liraglutide may thus represent a new clinical tool for the treatment of Dox-induced cardiotoxicity.

Understanding the Cautions and Contraindications of Immunomodulator and Biologic Therapies for Use in Inflammatory Bowel Disease

Ulcerative colitis and Crohn's disease are chronic inflammatory bowel diseases for which there are no cures. These diseases are immunopathogenic, and medical treatment is centered on the temperance of a dysregulated immune response to allow mucosal healing and prevent the sequelae of fistulation and stenosis. Accordingly, the armamentarium of medications, which has expanded immensely in recent history, is not without significant infectious and neoplastic risks. Many of these untoward effects can be mitigated by screening and avoidance of contraindicated medications. This review seeks to highlight the cautions for use of immunomodulators, anticytokine, and α4-integrin antagonists. The potential adverse events are further complicated by substantial heterogeneity in disease phenotype in the inflammatory bowel disease population. Large patient registries and databases provide considerable experience and knowledge to calculate the incidence of safety outcomes. To identify rarer outcomes after prolonged therapy, more prospective studies and continued adverse event reporting will aid safe application and minimize potential harms.

Anti-inflammatory effects of exercise: role in diabetes and cardiovascular disease

BACKGROUND

Persistent inflammation is involved in the pathogenesis of chronic diseases such as type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD).

AIMS

The aim of this review was to provide the reader with an update of the mechanisms whereby exercise-induced cytokines may impact cardiometabolic diseases.

RESULTS

Evidence exists that interleukin (IL)-1β is involved in pancreatic β-cell damage, whereas TNF-α is a key molecule in peripheral insulin resistance. In addition, TNF-α appears to be involved in the pathogenesis of atherosclerosis and heart failure. A marked increase in IL-6 and IL-10 is provoked by exercise and exerts direct anti-inflammatory effects by an inhibition of TNF-α and by stimulating IL-1ra, thereby limiting IL-1β signalling. Moreover, muscle-derived IL-6 appears to have direct anti-inflammatory effects and serves as a mechanism to improve glucose tolerance. In addition, indirect anti-inflammatory effects of long-term exercise are mediated via improvements in body composition.

CONCLUSION

Physical activity represents a natural, strong anti-inflammatory strategy with minor side effects and should be integrated in the management of patients with cardiometabolic diseases.

Unmet Needs in the Pathogenesis and Treatment of Cardiovascular Comorbidities in Chronic Inflammatory Diseases

The developments that have taken place in recent decades in the diagnosis and therapy of a number of diseases have led to improvements in prognosis and life expectancy. As a consequence, there has been an increase in the number of patients affected by chronic diseases and who can face new pathologies during their lifetime. The prevalence of chronic heart failure, for example, is approximately 1-2% of the adult population in developed countries, rising to ≥10% among people >70 years of age; in 2015, more than 85 million people in Europe were living with some sort of cardiovascular disease (CVD) (Lubrano and Balzan World J Exp Med 5:21-32, 5; Takahashi et al. Circ J 72:867-72, 8; Kaptoge et al. Lancet 375:132-40, 9). Chronic disease can become, in turn, a major risk factor for other diseases. Furthermore, several new drugs have entered clinical practice whose adverse effects on multiple organs are still to be evaluated. All this necessarily involves a multidisciplinary vision of medicine, where the physician must view the patient as a whole and where collaboration between the various specialists plays a key role. An example of what has been said so far is the relationship between CVD and chronic inflammatory diseases (CIDs). Patients with chronic CVD may develop a CID within their lifetime, and, vice versa, a CID can be a risk factor for the development of CVD. Moreover, drugs used for the treatment of CIDs may have side effects involving the cardiovascular system and thus may be contraindicated. The purpose of this paper is to investigate the close relationship between these two groups of diseases and to provide recommendations on the diagnostic approach and treatments in light of the most recent scientific data available.

Pediatric and adult dilated cardiomyopathy represent distinct pathological entities

Pediatric dilated cardiomyopathy (DCM) is the most common indication for heart transplantation in children. Despite similar genetic etiologies, medications routinely used in adult heart failure patients do not improve outcomes in the pediatric population. The mechanistic basis for these observations is unknown. We hypothesized that pediatric and adult DCM comprise distinct pathological entities, in that children do not undergo adverse remodeling, the target of adult heart failure therapies. To test this hypothesis, we examined LV specimens obtained from pediatric and adult donor controls and DCM patients. Consistent with the established pathophysiology of adult heart failure, adults with DCM displayed marked cardiomyocyte hypertrophy and myocardial fibrosis compared with donor controls. In contrast, pediatric DCM specimens demonstrated minimal cardiomyocyte hypertrophy and myocardial fibrosis compared with both age-matched controls and adults with DCM. Strikingly, RNA sequencing uncovered divergent gene expression profiles in pediatric and adult patients, including enrichment of transcripts associated with adverse remodeling and innate immune activation in adult DCM specimens. Collectively, these findings reveal that pediatric and adult DCM represent distinct pathological entities, provide a mechanistic basis to explain why children fail to respond to adult heart failure therapies, and suggest the need to develop new approaches for pediatric DCM.

TNF-α receptor 1 knockdown in the subfornical organ ameliorates sympathetic excitation and cardiac hemodynamics in heart failure rats

In systolic heart failure (HF), circulating proinflammatory cytokines upregulate inflammation and renin-angiotensin system (RAS) activity in cardiovascular regions of the brain, contributing to sympathetic excitation and cardiac dysfunction. Important among these is the subfornical organ (SFO), a forebrain circumventricular organ that lacks an effective blood-brain barrier and senses circulating humors. We hypothesized that the tumor necrosis factor-α (TNF-α) receptor 1 (TNFR1) in the SFO contributes to sympathetic excitation and cardiac dysfunction in HF rats. Rats received SFO microinjections of a TNFR1 shRNA or a scrambled shRNA lentiviral vector carrying green fluorescent protein, or vehicle. One week later, some rats were euthanized to confirm the accuracy of the SFO microinjections and the transfection potential of the lentiviral vector. Other rats underwent coronary artery ligation (CL) to induce HF or a sham operation. Four weeks after CL, vehicle- and scrambled shRNA-treated HF rats had significant increases in TNFR1 mRNA and protein, NF-κB activity, and mRNA for inflammatory mediators, RAS components and c-Fos protein in the SFO and downstream in the hypothalamic paraventricular nucleus, along with increased plasma norepinephrine levels and impaired cardiac function, compared with vehicle-treated sham-operated rats. In HF rats treated with TNFR1 shRNA, TNFR1 was reduced in the SFO but not paraventricular nucleus, and the central and peripheral manifestations of HF were ameliorated. In sham-operated rats treated with TNFR1 shRNA, TNFR1 expression was also reduced in the SFO but there were no other effects. These results suggest a key role for TNFR1 in the SFO in the pathophysiology of systolic HF.NEW & NOTEWORTHY Activation of TNF-α receptor 1 in the subfornical organ (SFO) contributes to sympathetic excitation in heart failure rats by increasing inflammation and renin-angiotensin system activity in the SFO and downstream in the hypothalamic paraventricular nucleus. Cytokine receptors in the SFO may be a target for central intervention in cardiovascular conditions characterized by peripheral inflammation.

Involvement of Cytokines in the Pathogenesis of Salt and Water Imbalance in Congestive Heart Failure

Congestive heart failure (CHF) has become a major medical problem in the western world with high morbidity and mortality rates. CHF adversely affects several systems, mainly the kidneys and the lungs. While the involvement of the renin-angiotensin-aldosterone system and the sympathetic nervous system in the progression of cardiovascular, pulmonary, and renal dysfunction in experimental and clinical CHF is well established, the importance of pro-inflammatory mediators in the pathogenesis of this clinical setting is still evolving. In this context, CHF is associated with overexpression of pro-inflammatory cytokines, such as tumor necrosis factor-α, interleukin (IL)-1, and IL-6, which are activated in response to environmental injury. This family of cytokines has been implicated in the deterioration of CHF, where it plays an important role in initiating and integrating homeostatic responses both at the myocardium and circulatory levels. We and others showed that angiotensin II decreased the ability of the lungs to clear edema and enhanced the fibrosis process via phosphorylation of the mitogen-activated protein kinases p38 and p42/44, which are generally involved in cellular responses to pro-inflammatory cytokines. Literature data also indicate the involvement of these effectors in modulating ion channel activity. It has been reported that in heart failure due to mitral stenosis; there were varying degrees of vascular and other associated parenchymal changes such as edema and fibrosis. In this review, we will discuss the effects of cytokines and other inflammatory mediators on the kidneys and the lungs in heart failure; especially their role in renal and alveolar ion channels activity and fluid balance.

Activated T Lymphocytes are Essential Drivers of Pathological Remodeling in Ischemic Heart Failure

BACKGROUND

Inappropriately sustained inflammation is a hallmark of chronic ischemic heart failure (HF); however, the pathophysiological role of T lymphocytes is unclear.

METHODS AND RESULTS

Permanent coronary ligation was performed in adult C57BL/6 mice. When compared with sham-operated mice, mice with HF (8 weeks after ligation) exhibited the following features: (1) significant (P<0.05) expansion of circulating CD3⁺CD8⁺ cytotoxic and CD3⁺CD4⁺ helper (Th) T lymphocytes, together with increased Th1, Th2, Th17, and regulatory T-cell (Treg) CD4⁺ subsets; (2) significant expansion of CD8⁺ and CD4⁺ T cells in failing myocardium, with increased Th1, Th2, Th17, and Treg CD4⁺ subsets, marked reduction of the Th1/Th2 ratio, augmentation of the Th17/Treg ratio, and upregulation of Th2 cytokines; and (3) significantly increased Th1, Th2, Th17 cells, and Tregs, in the spleen and mediastinal lymph nodes, with expansion of splenic antigen-experienced effector and memory CD4⁺ T cells. Antibody-mediated CD4⁺ T-cell depletion in HF mice (starting 4 weeks after ligation) reduced cardiac infiltration of CD4⁺ T cells and prevented progressive left ventricular dilatation and hypertrophy, whereas adoptive transfer of splenic CD4⁺ T cells (and, to a lesser extent, cardiac CD3⁺ T cells) from donor mice with HF induced long-term left ventricular dysfunction, fibrosis, and hypertrophy in naive recipient mice.

CONCLUSIONS

CD4⁺ T lymphocytes are globally expanded and activated in chronic ischemic HF, with Th2 (versus Th1) and Th17 (versus Treg) predominance in failing hearts, and with expansion of memory T cells in the spleen. Cardiac and splenic T cells in HF are primed to induce cardiac injury and remodeling, and retain this memory on adoptive transfer.

Autoantibody profiling on a plasmonic nano-gold chip for the early detection of hypertensive heart disease

The role of autoimmunity in cardiovascular (CV) diseases has been increasingly recognized. Autoimmunity is most commonly examined by the levels of circulating autoantibodies in clinical practices. Measurement of autoantibodies remains, however, challenging because of the deficiency of reproducible, sensitive, and standardized assays. The lack of multiplexed assays also limits the potential to identify a CV-specific autoantibody profile. To overcome these challenges, we developed a nanotechnology-based plasmonic gold chip for autoantibody profiling. This approach allowed simultaneous detection of 10 CV autoantibodies targeting the structural myocardial proteins, the neurohormonal regulatory proteins, the vascular proteins, and the proteins associated with apoptosis and coagulation. Autoantibodies were measured in four groups of participants across the continuum of hypertensive heart diseases. We observed higher levels of all 10 CV autoantibodies in hypertensive subjects (n = 77) compared with healthy participants (n = 30), and the autoantibodies investigated were related to each other, forming a highly linked network. In addition, we established that autoantibodies to troponin I, annexin-A5, and beta 1-adrenegic receptor best discriminated hypertensive subjects with adverse left ventricular (LV) remodeling or dysfunction (n = 49) from hypertensive subjects with normal LV structure and function (n = 28). By further linking these three significant CV autoantibodies to the innate and growth factors, we revealed a positive but weak association between autoantibodies to troponin I and proinflammatory cytokine IL-18. Overall, we demonstrated that this platform can be used to evaluate autoantibody profiles in hypertensive subjects at risk for heart failure.

Role of the immune system in cardiac tissue damage and repair following myocardial infarction

INTRODUCTION

The immune system plays a crucial role in the initiation, development, and resolution of inflammation following myocardial infarction (MI). The lack of oxygen and nutrients causes the death of cardiomyocytes and leads to the exposure of danger-associated molecular patterns that are recognized by the immune system to initiate inflammation.

RESULTS

At the initial stage of post-MI inflammation, the immune system further damages cardiac tissue to clear cell debris. The excessive production of reactive oxygen species (ROS) by immune cells and the inability of the anti-oxidant system to neutralize ROS cause oxidative stress that further aggravates inflammation. On the other hand, the cells of both innate and adaptive immune system and their secreted factors are critically instrumental in the very dynamic and complex processes of regulating inflammation and mediating cardiac repair.

CONCLUSIONS

It is important to decipher the balance between detrimental and beneficial effects of the immune system in MI. This enables us to identify better therapeutic targets for reducing the infarct size, sustaining the cardiac function, and minimizing the likelihood of heart failure. This review discusses the role of both innate and adaptive immune systems in cardiac tissue damage and repair in experimental models of MI.

Pathophysiology of heart failure and frailty: a common inflammatory origin?

Frailty, a clinical syndrome that typically occurs in older adults, implies a reduced ability to tolerate biological stressors. Frailty accompanies many age‐related diseases but can also occur without overt evidence of end‐organ disease. The condition is associated with circulating inflammatory cytokines and sarcopenia, features that are shared with heart failure (HF). However, the biological underpinnings of frailty remain unclear and the interaction with HF is complex. Here, we describe the inflammatory pathophysiology that is associated with frailty and speculate that the inflammation that occurs with frailty shares common origins with HF. We discuss the limitations in investigating the pathophysiology of frailty due to few relevant experimental models. Leveraging current therapies for advanced HF and current known therapies to address frailty in humans may enable translational studies to better understand the inflammatory interactions between frailty and HF.

Role of Inflammation in Heart Failure

PURPOSE OF REVIEW

This paper aims to discuss the interactions between inflammatory cytokines, immune cells, and heart failure (HF). The association of heart failure with inflammation has led to multiple studies on anti-inflammatory agents in acute and chronic heart failure.

RECENT FINDINGS

Recent findings have implicated leukocytes subclasses and multiple inflammatory mediators in the progression of heart failure and cardiovascular disease. Studies have discovered further details on the interaction between immune cells-particularly macrophages and lymphocytes-and inflammation. There are both cell-mediated and cytokine-mediated pathways of inflammation, which are interconnected. Additionally, a number of markers have been used and studied in heart failure disease progression. In this review, we discuss inflammatory biomarkers and immune cell mediators involved in HF. We will focus on the correlations and role of these inflammatory mediators in the genesis of HF. We will also discuss the evidence on beneficial effects of anti-inflammatory agents in the setting of chronic HF.

New Role for Interleukin-13 Receptor α1 in Myocardial Homeostasis and Heart Failure

BACKGROUND

The immune system plays a pivotal role in myocardial homeostasis and response to injury. Interleukins-4 and -13 are anti-inflammatory type-2 cytokines, signaling via the common interleukin-13 receptor α1 chain and the type-2 interleukin-4 receptor. The role of interleukin-13 receptor α1 in the heart is unknown.

METHODS AND RESULTS

We analyzed myocardial samples from human donors (n=136) and patients with end-stage heart failure (n=177). We found that the interleukin-13 receptor α1 is present in the myocardium and, together with the complementary type-2 interleukin-4 receptor chain Il4ra, is significantly downregulated in the hearts of patients with heart failure. Next, we showed that Il13ra1-deficient mice develop severe myocardial dysfunction and dyssynchrony compared to wild-type mice (left ventricular ejection fraction 29.7±9.9 versus 45.0±8.0; P=0.004, left ventricular end-diastolic diameter 4.2±0.2 versus 3.92±0.3; P=0.03). A bioinformatic analysis of mouse hearts indicated that interleukin-13 receptor α1 regulates critical pathways in the heart other than the immune system, such as extracellular matrix (normalized enrichment score=1.90; false discovery rate q=0.005) and glucose metabolism (normalized enrichment score=-2.36; false discovery rate q=0). Deficiency of Il13ra1 was associated with reduced collagen deposition under normal and pressure-overload conditions.

CONCLUSIONS

The results of our studies in humans and mice indicate, for the first time, a role of interleukin-13 receptor α1 in myocardial homeostasis and heart failure and suggests a new therapeutic target to treat heart disease.

The Soft- and Hard-Heartedness of Cardiac Fibroblasts: Mechanotransduction Signaling Pathways in Fibrosis of the Heart

Cardiac fibrosis, the excessive accumulation of extracellular matrix (ECM), remains an unresolved problem in most forms of heart disease. In order to be successful in preventing, attenuating or reversing cardiac fibrosis, it is essential to understand the processes leading to ECM production and accumulation. Cardiac fibroblasts are the main producers of cardiac ECM, and harbor great phenotypic plasticity. They are activated by the disease-associated changes in mechanical properties of the heart, including stretch and increased tissue stiffness. Despite much remaining unknown, an interesting body of evidence exists on how mechanical forces are translated into transcriptional responses important for determination of fibroblast phenotype and production of ECM constituents. Such mechanotransduction can occur at multiple cellular locations including the plasma membrane, cytoskeleton and nucleus. Moreover, the ECM functions as a reservoir of pro-fibrotic signaling molecules that can be released upon mechanical stress. We here review the current status of knowledge of mechanotransduction signaling pathways in cardiac fibroblasts that culminate in pro-fibrotic gene expression.

BET bromodomain inhibition suppresses innate inflammatory and profibrotic transcriptional networks in heart failure

Despite current standard of care, the average 5-year mortality after an initial diagnosis of heart failure (HF) is about 40%, reflecting an urgent need for new therapeutic approaches. Previous studies demonstrated that the epigenetic reader protein bromodomain-containing protein 4 (BRD4), an emerging therapeutic target in cancer, functions as a critical coactivator of pathologic gene transactivation during cardiomyocyte hypertrophy. However, the therapeutic relevance of these findings to human disease remained unknown. We demonstrate that treatment with the BET bromodomain inhibitor JQ1 has therapeutic effects during severe, preestablished HF from prolonged pressure overload, as well as after a massive anterior myocardial infarction in mice. Furthermore, JQ1 potently blocks agonist-induced hypertrophy in human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). Integrated transcriptomic analyses across animal models and human iPSC-CMs reveal that BET inhibition preferentially blocks transactivation of a common pathologic gene regulatory program that is robustly enriched for NFκB and TGF-β signaling networks, typified by innate inflammatory and profibrotic myocardial genes. As predicted by these specific transcriptional mechanisms, we found that JQ1 does not suppress physiological cardiac hypertrophy in a mouse swimming model. These findings establish that pharmacologically targeting innate inflammatory and profibrotic myocardial signaling networks at the level of chromatin is effective in animal models and human cardiomyocytes, providing the critical rationale for further development of BET inhibitors and other epigenomic medicines for HF.

Interleukin-1 blockade in heart failure with preserved ejection fraction: rationale and design of the Diastolic Heart Failure Anakinra Response Trial 2 (D-HART2)

Heart failure with preserved ejection fraction (HFpEF) now accounts for the majority of confirmed HF cases in the United States. However, there are no highly effective evidence-based treatments currently available for these patients. Inflammation correlates positively with adverse outcomes in HF patients. Interleukin (IL)-1, a prototypical inflammatory cytokine, has been implicated as a driver of diastolic dysfunction in preclinical animal models and a pilot clinical trial. The Diastolic Heart Failure Anakinra Response Trial 2 (D-HART2) is a phase 2, 2:1 randomized, double-blind, placebo-controlled clinical trial that will test the hypothesis that IL-1 blockade with anakinra (recombinant human IL-1 receptor antagonist) improves (1) cardiorespiratory fitness, (2) objective evidence of diastolic dysfunction, and (3) elevated inflammation in patients with HFpEF (http://www.ClinicalTrials.gov NCT02173548). The co-primary endpoints will be placebo-corrected interval changes in peak oxygen consumption and ventilatory efficiency at week 12. In addition, secondary and exploratory analyses will investigate the effects of IL-1 blockade on cardiac structure and function, systemic inflammation, endothelial function, quality of life, body composition, nutritional status, and clinical outcomes. The D-HART2 clinical trial will add to the growing body of evidence on the role of inflammation in cardiovascular disease, specifically focusing on patients with HFpEF.

The Biological Basis for Cardiac Repair After Myocardial Infarction: From Inflammation to Fibrosis

In adult mammals, massive sudden loss of cardiomyocytes after infarction overwhelms the limited regenerative capacity of the myocardium, resulting in the formation of a collagen-based scar. Necrotic cells release danger signals, activating innate immune pathways and triggering an intense inflammatory response. Stimulation of toll-like receptor signaling and complement activation induces expression of proinflammatory cytokines (such as interleukin-1 and tumor necrosis factor-α) and chemokines (such as monocyte chemoattractant protein-1/ chemokine (C-C motif) ligand 2 [CCL2]). Inflammatory signals promote adhesive interactions between leukocytes and endothelial cells, leading to extravasation of neutrophils and monocytes. As infiltrating leukocytes clear the infarct from dead cells, mediators repressing inflammation are released, and anti-inflammatory mononuclear cell subsets predominate. Suppression of the inflammatory response is associated with activation of reparative cells. Fibroblasts proliferate, undergo myofibroblast transdifferentiation, and deposit large amounts of extracellular matrix proteins maintaining the structural integrity of the infarcted ventricle. The renin-angiotensin-aldosterone system and members of the transforming growth factor-β family play an important role in activation of infarct myofibroblasts. Maturation of the scar follows, as a network of cross-linked collagenous matrix is formed and granulation tissue cells become apoptotic. This review discusses the cellular effectors and molecular signals regulating the inflammatory and reparative response after myocardial infarction. Dysregulation of immune pathways, impaired suppression of postinfarction inflammation, perturbed spatial containment of the inflammatory response, and overactive fibrosis may cause adverse remodeling in patients with infarction contributing to the pathogenesis of heart failure. Therapeutic modulation of the inflammatory and reparative response may hold promise for the prevention of postinfarction heart failure.

Prognostic Implications of Serum Albumin Levels in Patients With Acute Coronary Syndromes

Hypoalbuminemia is a long-term risk factor for incident of both myocardial infarction and heart failure. We assessed whether serum albumin levels at admission are associated with new-onset heart failure and in-hospital mortality in patients with acute coronary syndrome (ACS). The study included 7,192 patients with ACS with no previous history of heart failure. Patients were divided into quartiles according to serum albumin levels (Q1: ≤3.50 g/dl; Q2: 3.51 to 3.80 g/dl; Q3: 3.81 to 4.08 g/dl; and Q4: >4.08 g/dl). Logistic regressions were used to explore the relations among serum albumin quartiles, new-onset heart failure, and in-hospital mortality. Serum albumin levels were negatively correlated with both high-sensitivity C-reactive protein and white blood cell count at admission. The unadjusted rate for both new-onset heart failure (37.7%, 20.2%, 14.7%, and 11.4% for Q1, Q2, Q3, and Q4, respectively; p <0.0001) and in-hospital mortality (9.8%, 3.4%, 2.0%, and 1.7% for Q1, Q2, Q3, and Q4, respectively; p <0.0001) were higher at lower serum albumin levels. Multivariate analysis demonstrated that serum albumin level ≤3.50 g/dl is an important and independent predictor of both the development of new-onset heart failure (odds ratio 2.31, 95% CI 1.87 to 2.84, p <0.0001) and in-hospital mortality (odds ratio 1.88, 95% CI 1.23 to 2.86, p = 0.003). In conclusion, albumin level ≤3.50 g/dl is an independent predictor of new-onset heart failure and in-hospital mortality in patients with ACS. The inflammatory state may be a mechanism underlying hypoalbuminemia in this clinical setting.

Leukocyte Trafficking in Cardiovascular Disease: Insights from Experimental Models

Chemokine-induced leukocyte migration into the vessel wall is an early pathological event in the progression of atherosclerosis, the underlying cause of myocardial infarction. The immune-inflammatory response, mediated by both the innate and adaptive immune cells, is involved in the initiation, recruitment, and resolution phases of cardiovascular disease progression. Activation of leukocytes via inflammatory mediators such as chemokines, cytokines, and adhesion molecules is instrumental in these processes. In this review, we highlight leukocyte activation with the main focus being on the mechanisms of chemokine-mediated recruitment in atherosclerosis and the response postmyocardial infarction with key examples from experimental models of cardiovascular inflammation.