Targeting interleukin-1 in heart disease

Vascular and Cardiac Oxidative Stress and Inflammation as Targets for Cardioprotection

Cardiac and vascular diseases are often associated with increased oxidative stress and inflammation, and both may contribute to the disease progression. However, successful applications of antioxidants in the clinical setting are very rare and specific anti-inflammatory therapeutics only emerged recently. Reasons for this rely on the great diversity of oxidative stress and inflammatory cells that can either act as cardioprotective or cause tissue damage in the heart. Recent large-scale clinical trials found that highly specific anti-inflammatory therapies using monoclonal antibodies against cytokines resulted in lower cardiovascular mortality in patients with pre-existing atherosclerotic disease. In addition, unspecific antiinflammatory medication and established cardiovascular drugs with pleiotropic immunomodulatory properties such as angiotensin converting enzyme (ACE) inhibitors or statins have proven beneficial cardiovascular effects. Normalization of oxidative stress seems to be a common feature of these therapies, which can be explained by a close interaction/crosstalk of the cellular redox state and inflammatory processes. In this review, we give an overview of cardiac reactive oxygen species (ROS) sources and processes of cardiac inflammation as well as the connection of ROS and inflammation in ischemic cardiomyopathy in order to shed light on possible cardioprotective interventions.

The Role of Rilonacept in Recurrent Pericarditis

Recurrent pericarditis is associated with significant morbidity and adverse impact on quality of life. Contemporary studies have emphasized the key role of autoinflammatory pathways in its pathophysiology, mainly through the activation of inflammasomes and the production of interleukin (IL)-1α and IL-1β. The IL-1 pathway has emerged as a promising target for the treatment of these patients. A novel IL-1 inhibitor, rilonacept, functions as an IL-1 trap binding to the circulating IL-1α and IL-1β mitigating their inflammatory response. Recently, the RHAPSODY phase III clinical trial evaluated the use of rilonacept in patients with recurrent pericarditis, who were refractory to colchicine, or steroid-dependent. Rilonacept significantly reduced symptoms, inflammatory markers and recurrent episodes, and increased successful withdrawal of steroids. The safety profile of the medication is favourable and well tolerated by patients, with local injection site reaction being the most common side effect described. These results have shifted the paradigm of the understanding of the disease and promise to become part of the armamentarium of medications for the standard of care of these patients, with potential use as monotherapy. The changing landscape of therapeutics and pathophysiology warrants increased recognition and understanding from the international cardiology community about this novel drug and its implication in managing these complex patients.The objective of this review is to describe the bio-action of rilonacept in the treatment of recurrent pericarditis.

COVID-19 and cardiovascular diseases

The coronavirus disease 2019 (COVID-19) remains a global public health emergency. Despite being caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), besides the lung, this infectious disease also has severe implications in the cardiovascular system. In this review, we summarize diverse clinical complications of the heart and vascular system, as well as the relevant high mortality, in COVID-19 patients. Systemic inflammation and angiotensin-converting enzyme 2-involved signaling networking in SARS-CoV-2 infection and the cardiovascular system may contribute to the manifestations of cardiovascular diseases. Therefore, integration of clinical observations and experimental findings can promote our understanding of the underlying mechanisms, which would aid in identifying and treating cardiovascular injury in patients with COVID-19 appropriately.

Inflammasomes as therapeutic targets in human diseases

Inflammasomes are protein complexes of the innate immune system that initiate inflammation in response to either exogenous pathogens or endogenous danger signals. Inflammasome multiprotein complexes are composed of three parts: a sensor protein, an adaptor, and pro-caspase-1. Activation of the inflammasome leads to the activation of caspase-1, which cleaves pro-inflammatory cytokines such as IL-1β and IL-18, leading to pyroptosis. Effectors of the inflammasome not only provide protection against infectious pathogens, but also mediate control over sterile insults. Aberrant inflammasome signaling has been implicated in the development of cardiovascular and metabolic diseases, cancer, and neurodegenerative disorders. Here, we review the role of the inflammasome as a double-edged sword in various diseases, and the outcomes can be either good or bad depending on the disease, as well as the genetic background. We highlight inflammasome memory and the two-shot activation process. We also propose the M- and N-type inflammation model, and discuss how the inflammasome pathway may be targeted for the development of novel therapy.

Inflammatory Cytokines, Immune Cells, and Organ Interactions in Heart Failure

Despite mounting evidence demonstrating the significance of inflammation in the pathophysiological mechanisms of heart failure (HF), most large clinical trials that target the inflammatory responses in HF yielded neutral or even worsening outcomes. Further in-depth understanding about the roles of inflammation in the pathogenesis of HF is eagerly needed. This review summarizes cytokines, cardiac infiltrating immune cells, and extracardiac organs that orchestrate the complex inflammatory responses in HF and highlights emerging therapeutic targets.

Rapid Release of Interleukin-1β from Human Platelets Is Independent of NLRP3 and Caspase

OBJECTIVE

 Platelets are critical in mediating both rapid responses to injury and the development and progression of coronary disease. Several studies have shown that, after prolonged exposure to agonists, they produce and release inflammatory mediators including interleukin-1β (IL-1β), via the classical pathway (NLRP3 inflammasome and caspase-1 cleavage to release active IL-1β) as described for leukocytes. This study aimed to determine whether there is rapid release of IL-1β in response to soluble platelet agonists and whether such rapid release is NLRP3- and caspase-1-dependent.

METHODS AND RESULTS

 Using flow cytometry to detect platelet activation (and release of α and dense granule contents) and the combination of Western blotting, enzyme-linked-immunosorbent assay, and immunogold labeling transmission electron and immunofluorescence microscopy, we identified that resting human platelets contain mature IL-1β. Platelets release IL-1β within minutes in response to adenosine diphosphate (ADP), collagen, and thrombin receptor agonists, but not in response to conventional NLRP3 inflammasome agonists-lipopolysaccharide and adenosine triphosphate. The rapid release of IL-1β in response to ADP and thrombin receptor agonists was independent of caspases (including caspase-1) and NLRP3. Immature and mature IL-1β were identified as low-abundance proteins on transmission electron microscopy of human platelets, and were localized to the platelet cytosol, open canalicular system, and the periphery of α granules.

CONCLUSION

 Unlike monocytes and neutrophils, human platelets are capable of rapid agonist- and time-dependent release of IL-1β by a mechanism which is independent of caspase-1 and NLRP3.

The Role of Melatonin on NLRP3 Inflammasome Activation in Diseases

NLRP3 inflammasome is a part of the innate immune system and responsible for the rapid identification and eradication of pathogenic microbes, metabolic stress products, reactive oxygen species, and other exogenous agents. NLRP3 inflammasome is overactivated in several neurodegenerative, cardiac, pulmonary, and metabolic diseases. Therefore, suppression of inflammasome activation is of utmost clinical importance. Melatonin is a ubiquitous hormone mainly produced in the pineal gland with circadian rhythm regulatory, antioxidant, and immunomodulatory functions. Melatonin is a natural product and safer than most chemicals to use for medicinal purposes. Many in vitro and in vivo studies have proved that melatonin alleviates NLRP3 inflammasome activity via various intracellular signaling pathways. In this review, the effect of melatonin on the NLRP3 inflammasome in the context of diseases will be discussed.

Preservation of Contractile Reserve and Diastolic Function by Inhibiting the NLRP3 Inflammasome with OLT1177® (Dapansutrile) in a Mouse Model of Severe Ischemic Cardiomyopathy Due to Non-Reperfused Anterior Wall Myocardial Infarction

Interleukin-1β (IL-1β), a product of the NLRP3 inflammasome, modulates cardiac contractility and diastolic function. We proposed that OLT1177^® (dapansutrile), a novel NLRP3 inhibitor, could preserve contractile reserve and diastolic function after myocardial infarction (MI). We used an experimental murine model of severe ischemic cardiomyopathy through the ligation of the left coronary artery without reperfusion, and after 7 days randomly assigned mice showing large anterior MI (>4 akinetic segments), increased left ventricular (LV) dimensions ([LVEDD] > 4.4 mm), and reduced function (LV ejection fraction < 40%) to a diet that was enriched with OLT1177^® admixed with the chow in the diet at 3.75 g/kg (Group 1 [n = 10]) or 7.5 g/kg (Group 2 [n = 9]), or a standard diet as the no-treatment control group (Group 3 [n = 10]) for 9 weeks. We measured the cardiac function and contractile reserve with an isoproterenol challenge, and the diastolic function with cardiac catheterization at 10 weeks following the MI surgery. When compared with the control (Group 3), the mice treated with OLT1177 (Group 1 and 2) showed significantly greater preservation of their contractile reserve (the percent increase in the left ventricular ejection fraction [LVEF] after the isoproterenol challenge was +33 ± 11% and +40 ± 6% vs. +9 ± 7% in the standard diet; p < 0.05 and p < 0.005 for Group 1 and 2, respectively) and of diastolic function measured as the lower left ventricular end-diastolic pressure (3.2 ± 0.5 mmHg or 4.5 ± 0.5 mmHg vs. 10.0 ± 1.6 mmHg; p < 0.005 and p < 0.009 respectively). No differences were noted between the resting LVEF of the MI groups. These effects were independent of the effects on the ventricular remodeling after MI. NLRP3 inflammasome inhibition with OLT1177^® can preserve β-adrenergic responsiveness and prevent left ventricular diastolic dysfunction in a large non-reperfused anterior MI mouse model. OLT1177^® could therefore be used to prevent the development of heart failure in patients with ischemic cardiomyopathy.

Effect of Biologics on Cardiovascular Inflammation: Mechanistic Insights and Risk Reduction

It is increasingly recognized that atherosclerosis and consequently cardiovascular disease (CVD) are closely linked with inflammatory processes. The latter is in the center of the pathogenic mechanism underlying autoimmune rheumatic diseases (ARD). It follows then, that optimal control of inflammation in ARDs may lead to a decrease of the accompanied CVD risk. Major trials (eg, CANTOS, CIRT), aimed at examining the possible benefits of immunomodulatory treatments in CVD, demonstrated conflicting results. On the other hand, substantial evidence is accumulating about the possible beneficial effects of biologic disease modifying antirheumatic drugs (bDMARDs) in patients with ARDs, particularly those with rheumatoid arthritis (RA). It seems that bDMARDs (some more than others) alter the lipid profile in RA patients but do not adversely affect, in most cases, the TC/HDL ratio. Favorable effects are noted for arterial stiffness and endothelial function. This is reflected in the lower risk for CVD events, seen in observational studies of RA patients treated with bDMARDs. It should be stressed that more data exist for the TNF-inhibitors than for other bDMARDs, such as tocilizumab, abatacept and rituximab. As regards the spondyloarthropathies (SpA), data are less robust. For TNF-inhibitors, effects appear to be on par with those seen in RA but no conclusions can be drawn for newer biologic drugs used in SpA (eg, IL-17 blockers). Finally, there is accumulating evidence for a beneficial effect of immunosuppressive treatment in cardiac inflammation and function in several ARDs. Introduction of newer therapeutic options in clinical practice seem to have a positive impact on CVD in the setting of ARD. This is probably due to better control of inflammation, but direct improvement in vascular pathology is also a valid hypothesis. Most data are derived from observational studies and, therefore, randomized controlled trials are needed to assess the possible favorable effect of bDMARDs on CVD outcomes.

Circulating PGLYRP1 Levels as a Potential Biomarker for Coronary Artery Disease and Heart Failure

ABSTRACT

Coronary artery disease (CAD) and associated comorbidities such as heart failure (HF) remain the leading cause of morbidity and mortality worldwide attributed to, at least partially, the lack of biomarkers for efficient disease diagnosis. Here, we evaluated the diagnostic potential of serum peptidoglycan recognition protein 1 (PGLYRP1), an important component of the innate immunity and inflammation system, for both CAD and HF. A machine-learning method (random forest) was used to evaluate the clinical utility of circulating PGLYRP1 for diagnosis of CAD and HF in a total of 370 individuals. Causal links of chronic serum PGLYRP1 elevation to both diseases were further explored in ApoE-/- mice. The serum levels of PGLYRP1 were significantly higher in individuals with either chronic CAD or acute coronary syndrome than those in those without coronary artery stenosis (the control group) and even more pronounced in CAD individuals with concomitant HF. Our random forest classifier revealed that this protein performed better than other recommended clinical indicators in distinguishing the CAD from the control individuals. In addition, this protein associates more with the biomarkers of HF including left ventricular ejection fraction than inflammation. Notably, our mice experiment indicated that long-term treatment with recombinant PGLYRP1 could significantly impair the cardiovascular system as reflected from both increased atherogenic lesions and reduced fractional shortening of the left ventricle. Our findings, therefore, supported the circulating levels of PGLYRP1 as a valuable biomarker for both CAD and HF.

Interleukin-1 blockade with RPH-104 in patients with acute ST-elevation myocardial infarction: study design and rationale

Background

Myocardial injury of ST-segment elevation myocardial infarction (STEMI) initiates an intense inflammatory response that contributes to further damage and is a predictor of increased risk of death or heart failure (HF). Interleukin-1 (IL-1) is a key mediator of local and systemic inflammatory response to myocardial damage. We postulate that the use of the drug RPH-104, which selectively binds and inactivates both α and β isoforms of IL-1 will lead to a decrease in the severity of the inflammatory response which will be reflected by decrease in the concentration of hsCRP, as well as the rate of fatal outcomes, frequency of new cases of HF, changes in levels of brain natriuretic peptide (BNP) and changes in structural and functional echocardiographic parameters.

Methods

This is a double blind, randomized, placebo-controlled study in which 102 patients with STEMI will receive a single administration of RPH-104 80 mg, RPH-104 160 mg or placebo (1:1:1). The primary endpoint will be hsCRP area under curve (AUC) from day 1 until day 14. Secondary endpoints will include hsCRP AUC from day 1 until day 28, rate of fatal outcomes, hospitalizations due to HF and other cardiac and non-cardiac reasons during 12-month follow-up period, frequency of new cases of HF, changes in levels of brain natriuretic peptide (BNP, NT-pro-BNP), changes in structural and functional echocardiographic parameters during 12-month follow-up period compared to baseline. The study started in October 2020 and is anticipated to end in 2Q 2022.

Trial registration: ClinicalTrials.gov, NCT04463251. Registered on July 9, 2020

Interleukin-1 and Systemic Sclerosis: Getting to the Heart of Cardiac Involvement

Systemic sclerosis (SSc) is rare, severe connective tissue disease characterized by endothelial and vascular damage, immune activation, and resulting in inflammation and fibrosis of skin and internal organs, including the heart. SSc is associated with high morbidity and mortality. Cardiac involvement is frequent in SSc patients, even though often asymptomatic at early stages, and represents one of the major causes of SSc-related mortality. Heart involvement has a variable clinical presentation, and its pathogenesis is not completely understood. Myocardial fibrosis is traditionally considered the immunopathologic hallmark of heart involvement in SSc. This unique histological feature is paralleled by distinctive clinical and prognostic features. The so-called "vascular hypothesis" represents the most credited hypothesis to explain myocardial fibrosis. More recently, the prominent role of an inflammatory myocardial process has been identified as a cardinal event in the evolution to fibrosis, thus also delineating an "inflammation-driven pathway to fibrosis". The pro-inflammatory cytokine interleukin (IL)-1 has an apical and cardinal role in the myocardial inflammatory cascade and in cardiac dysfunction. The primary aim of this perspective article is: to present the emerging evidence on the role of IL-1 and inflammasome in both SSc and heart inflammation, to review the complex interplay between cellular metabolism and inflammasome activation, and to discuss the rationale for targeted inhibition of IL-1 for the treatment of SSc-heart involvement, providing preliminary experimental and clinical data to support this hypothesis.

Impact of sodium glucose cotransporter 2 (SGLT2) inhibitors on atherosclerosis: from pharmacology to pre-clinical and clinical therapeutics

Sodium-glucose cotransporter 2 inhibitors (SGLT2i) are new oral drugs for the therapy of patients with type 2 diabetes mellitus (T2DM). Research in the past decade has shown that drugs of the SGLT2i class, such as empagliflozin, canagliflozin, and dapagliflozin, have pleiotropic effects in preventing cardiovascular diseases beyond their favorable impact on hyperglycemia. Of clinical relevance, recent landmark cardiovascular outcome trials have demonstrated that SGLT2i reduce major adverse cardiovascular events, hospitalization for heart failure, and cardiovascular death in T2DM patients with/without cardiovascular diseases (including atherosclerotic cardiovascular diseases and various types of heart failure). The major pharmacological action of SGLT2i is through inhibiting glucose re-absorption in the kidney and thus promoting glucose excretion. Studies in experimental models of atherosclerosis have shown that SGLT2i ameliorate the progression of atherosclerosis by mechanisms including inhibition of vascular inflammation, reduction in oxidative stress, reversing endothelial dysfunction, reducing foam cell formation and preventing platelet activation. Here, we summarize the anti-atherosclerotic actions and mechanisms of action of SGLT2i, with an aim to emphasize the clinical utility of this class of agents in preventing the insidious cardiovascular complications accompanying diabetes.

Post-Stroke Cardiovascular Complications and Neurogenic Cardiac Injury: JACC State-of-the-Art Review

Over 1.5 million deaths worldwide are caused by neurocardiogenic syndromes. Furthermore, the consequences of deleterious brain-heart interactions are not limited to fatal complications. Cardiac arrhythmias, heart failure, and nonfatal coronary syndromes are also common. The brain-heart axis is implicated in post-stroke cardiovascular complications known as the stroke-heart syndrome, sudden cardiac death, and Takotsubo syndrome, among other neurocardiogenic syndromes. Multiple pathophysiological mechanisms with the potential to be targeted with novel therapies have been identified in the last decade. In the present state-of-the-art review, we describe recent advances in the understanding of anatomical and functional aspects of the brain-heart axis, cardiovascular complications after stroke, and a comprehensive pathophysiological model of stroke-induced cardiac injury.

NLRP3 Inflammasome Inhibitors in Cardiovascular Diseases

Virtually all types of cardiovascular diseases are associated with pathological activation of the innate immune system. The NACHT, leucine-rich repeat (LRR), and pyrin domain (PYD)-containing protein 3 (NLRP3) inflammasome is a protein complex that functions as a platform for rapid induction of the inflammatory response to infection or sterile injury. NLRP3 is an intracellular sensor that is sensitive to danger signals, such as ischemia and extracellular or intracellular alarmins during tissue injury. The NLRP3 inflammasome is regulated by the presence of damage-associated molecular patterns and initiates or amplifies inflammatory response through the production of interleukin-1β (IL-1β) and/or IL-18. NLRP3 activation regulates cell survival through the activity of caspase-1 and gasdermin-D. The development of NLRP3 inflammasome inhibitors has opened the possibility to targeting the deleterious effects of NLRP3. Here, we examine the scientific evidence supporting a role for NLRP3 and the effects of inhibitors in cardiovascular diseases.

Anakinra in Recurrent Pericarditis: Current Evidence on Clinical Use, Effectiveness, and Safety

Anakinra is a recombinant human interleukin 1 receptor antagonist that competes and blocks the biologic effects of interleukin 1, reducing systemic inflammatory responses. In the 2015 guidelines for the diagnosis and management of pericardial diseases of the European Society of Cardiology, anakinra was established as a third-line therapy option for refractory recurrent pericarditis (RP). Recently, important studies that investigates the effect and safety of anakinra in RP were published, such as the AIRTRIP trial and the International Registry of Anakinra for Pericarditis. This article presents the current evidence about the effectiveness and safety of anakinra in RP and discusses its clinical application and mechanisms.

Interleukin-1 Beta in Peripheral Blood Mononuclear Cell Lysates as a Longitudinal Biomarker of Response to Antidepressants: A Pilot Study

Interleukin-1 beta (IL1β) is primarily produced by monocytes in the periphery and the brain. Yet, IL1β protein levels have to date been investigated in major depressive disorder (MDD) and antidepressant response using either plasma or serum assays although with contradictory results, while mononuclear cell assays are lacking despite their extensive use in other contexts. In this pilot study, we comparatively assessed IL1β in mononuclear lysates and plasma in depressed MDD patients over treatment and healthy controls (HC). We recruited 31 consecutive adult MDD inpatients and 25 HC matched on age, sex, and BMI. Twenty-six patients completed an 8-week follow-up under treatment. IL1β was measured in both lysates and plasma in patients at baseline (T0) and at study end (T1) as well as in HC. We calculated ΔIL1β(%) for both lysates and plasma as IL1β percent changes from T0 to T1. Seventeen patients (65.4% of completers) were responders at T1 and had lower baseline BMI than non-responders (p = 0.029). Baseline IL1β from either plasma or lysates could not efficiently discriminate between depressed patients and HC, or between responders and non-responders. However, the two response groups displayed contrasting IL1β trajectories in lysates but not in plasma assays (response group by time interactions, p = 0.005 and 0.96, respectively). ΔIL1β(%) in lysates predicted response (p = 0.025, AUC = 0.81; accuracy = 84.6%) outperforming ΔIL1β(%) in plasma (p = 0.77, AUC=0.52) and was robust to adjusting for BMI. In conclusion, ΔIL1β(%) in mononuclear lysates may be a longitudinal biomarker of antidepressant response, potentially helpful in avoiding untimely switching of antidepressants, thereby warranting further investigation.

Inflammation in Heart Failure: JACC State-of-the-Art Review

It has long been observed that heart failure (HF) is associated with measures of systemic inflammation. In recent years, there have been significant advancements in our understanding of how inflammation contributes to the pathogenesis and progression of HF. However, although numerous studies have validated the association between measures of inflammation and HF severity and prognosis, clinical trials of anti-inflammatory therapies have proven mostly unsuccessful. On this backdrop emerges the yet unmet goal of targeting precise phenotypes within the syndrome of HF; if such precise definitions can be realized, and with better understanding of the roles played by specific inflammatory mediators, the expectation is that targeted anti-inflammatory therapies may improve prognosis in patients whose HF is driven by inflammatory pathobiology. Here, the authors describe mechanistic links between inflammation and HF, discuss traditional and novel inflammatory biomarkers, and summarize the latest evidence from clinical trials of anti-inflammatory therapies.

Comparative clinical study evaluating the effect of adding Vildagliptin versus Glimepiride to ongoing Metformin therapy on diabetic patients with symptomatic coronary artery disease

BACKGROUND AND OBJECTIVE

Cardiovascular diseases (CVDs) remain the most identified cause of death in patients with diabetes mellitus (DM). This study aimed to evaluate the effect of adding Vildagliptin versus Glimepiride to ongoing Metformin on the biomarkers of inflammation, thrombosis, and atherosclerosis in T2DM patients with symptomatic coronary artery disease (CAD).

METHODS

This study included 80 patients with uncontrolled T2DM and symptomatic CAD who were randomized to add either Vildagliptin 50 mg/day "group I" or Glimepiride 4 mg/day "group II" to ongoing Metformin therapy (1000 mg/day). Blood samples were collected at baseline and 3 months after intervention for biochemical analysis of HbA1c %, IL-1β, adiponectin, hsCRP and lipid profile. Additionally atherogenic index (AI) and coronary risk index (CRI) were determined.

RESULTS

Three months after intervention and as compared to group II (Glimepiride/Metformin), group 1 (Vildagliptin/Metformin) showed significantly lower BMI (28.73 ± 3.48 versus 30.55 ± 3.15; p = 0.02), HbA1c (6.05 ± 0.72 versus 7.06 ± 0.89; p < 0.0001), hsCRP (0.96 ± 0.20 versus 1.72 ± 0.38; p < 0.0001), IL-1β (34.95 ± 10.01 versus 45.13 ± 10.26; p < 0.0001), TC (136 ± 23.45 versus 169 ± 35.72; p < 0.0001), TG (116 ± 29.10 versus 146 ± 56.58; p = 0.005), and CRI (2.47 ± 0.90 versus 3.65 ± 1.19; p < 0.0001) which was associated with significantly higher adiponectin and HDL-C (4.42 ± 1.29 versus 2.52 ± 1.86; p < 0.0001 and 61 ± 23.04 versus 48 ± 12.92; p = 0.003 respectively).

CONCLUSION

In patients with T2DM and symptomatic CAD, the addition of Vildagliptin to ongoing metformin showed better glycemic control, lower inflammatory markers (IL-1β and hsCRP), higher protective markers (adiponectin and HDL-C) and improved lipid profile compared to Glimepiride/metformin therapy.

The Effects of Targeted Temperature Management on Oxygen-Glucose Deprivation/Reperfusion-Induced Injury and DAMP Release in Murine Primary Cardiomyocytes

Introduction. Ischemia/Reperfusion (I/R) is a primary cause of myocardial injury after acute myocardial infarction resulting in the release of damage-associated molecular patterns (DAMPs), which can induce a sterile inflammatory response in the myocardial penumbra. Targeted temperature management (TTM) after I/R has been established for neuroprotection, but the cardioprotective effect remains to be elucidated. Therefore, we investigated the effect of TTM on cell viability, immune response, and DAMP release during oxygen-glucose deprivation/reperfusion (OGD/R) in murine primary cardiomyocytes. Methods. Primary cardiomyocytes from P1-3 mice were exposed to 2, 4, or 6 hours OGD (0.2% oxygen in medium without glucose and serum) followed by 6, 12, or 24 hours simulated reperfusion (21% oxygen in complete medium). TTM at 33.5°C was initiated intra-OGD, and a control group was maintained at 37°C normoxia. Necrosis was assessed by lactate dehydrogenase (LDH) release and apoptosis by caspase-3 activation. OGD-induced DAMP secretions were assessed by Western blotting. Inducible nitric oxide synthase (iNOS), cytokines, and antiapoptotic RBM3 and CIRBP gene expressions were measured by quantitative polymerase chain reaction. Results. Increasing duration of OGD resulted in a transition from apoptotic programmed cell death to necrosis, as observed by decreasing caspase-3 cleavage and increasing LDH release. DAMP release and iNOS expression correlated with increasing necrosis and were effectively attenuated by TTM initiated during OGD. Moreover, TTM induced expression of antiapoptotic RBM3 and CIRBP. Conclusion. TTM protects the myocardium by attenuating cardiomyocyte necrosis induced by OGD and caspase-3 activation, possibly via induction of antiapoptotic RBM3 and CIRBP expressions, during reperfusion. OGD induces increased Hsp70 and CIRBP releases, but HMGB-1 is the dominant mediator of inflammation secreted by cardiomyocytes after prolonged exposure. TTM has the potential to attenuate DAMP release.

CD40/CD40L and Related Signaling Pathways in Cardiovascular Health and Disease-The Pros and Cons for Cardioprotection

The CD40–CD40 ligand (CD40L) dyad represents a scientific and clinical field that has raised many controversies in the past and cannot be clearly defined as being an either beneficial or harmful pathway. Being crucially involved in physiological immunological processes as well as pathological inflammatory reactions, the signaling pathway has been recognized as a key player in the development of both autoimmune and cardiovascular disease. Even though the possibilities of a therapeutic approach to the dyad were recognized decades ago, due to unfortunate events, detailed in this review, pharmacological treatment targeting the dyad, especially in patients suffering from atherosclerosis, is not available. Despite the recent advances in the treatment of classical cardiovascular risk factors, such as arterial hypertension and diabetes mellitus, the treatment of the associated low-grade inflammation that accounts for the progression of atherosclerosis is still challenging. Low-grade inflammation can be detected in a significant portion of patients that suffer from cardiovascular disease and it is therefore imperative to develop new therapeutic strategies in order to combat this driver of atherosclerosis. Of note, established cardiovascular drugs such as angiotensin-converting enzyme inhibitors or statins have proven beneficial cardiovascular effects that are also related to their pleiotropic immunomodulatory properties. In this review, we will discuss the setbacks encountered as well as new avenues discovered on the path to a different, inflammation-centered approach for the treatment of cardiovascular disease with the CD40–CD40L axis as a central therapeutic target.

Prevention of radiotherapy-induced arterial inflammation by interleukin-1 blockade

Aims

Radiotherapy-induced cardiovascular disease is an emerging problem in a growing population of cancer survivors where traditional treatments, such as anti-platelet and lipid-lowering drugs, have limited benefits. The aim of the study was to investigate vascular inflammatory patterns in human cancer survivors, replicate the findings in an animal model, and evaluate whether interleukin-1 (IL-1) inhibition could be a potential treatment.

Methods and results

Irradiated human arterial biopsies were collected during microvascular autologous free tissue transfer for cancer reconstruction and compared with non-irradiated arteries from the same patient. A mouse model was used to study the effects of the IL-1 receptor antagonist, anakinra, on localized radiation-induced vascular inflammation. We observed significant induction of genes associated with inflammasome biology in whole transcriptome analysis of irradiated arteries, a finding supported by elevated protein levels in irradiated arteries of both, pro-caspase and caspase-1. mRNA levels of inflammasome associated chemokines CCL2, CCL5 together with the adhesion molecule VCAM1, were elevated in human irradiated arteries as was the number of infiltrating macrophages. A similar pattern was reproduced in Apoe−/− mouse 10 weeks after localized chest irradiation with 14 Gy. Treatment with anakinra in irradiated mice significantly reduced Ccl2 and Ccl5 mRNA levels and expression of I-A^b.

Conclusion

Anakinra, administered directly after radiation exposure for 2 weeks, ameliorated radiation induced sustained expression of inflammatory mediators in mice. Further studies are needed to evaluate IL-1 blockade as a treatment of radiotherapy-induced vascular disease in a clinical setting.

Pathological Responses of Cardiac Mitochondria to Burn Trauma

Despite advances in treatment and care, burn trauma remains the fourth most common type of traumatic injury. Burn-induced cardiac failure is a key factor for patient mortality, especially during the initial post-burn period (the first 24 to 48 h). Mitochondria, among the most important subcellular organelles in cardiomyocytes, are a central player in determining the severity of myocardial damage. Defects in mitochondrial function and structure are involved in pathogenesis of numerous myocardial injuries and cardiovascular diseases. In this article, we comprehensively review the current findings on cardiac mitochondrial pathological changes and summarize burn-impaired mitochondrial respiration capacity and energy supply, induced mitochondrial oxidative stress, and increased cell death. The molecular mechanisms underlying these alterations are discussed, along with the possible influence of other biological variables. We hope this review will provide useful information to explore potential therapeutic approaches that target mitochondria for cardiac protection following burn injury.

Revisiting pharmacology of oxidative stress and endothelial dysfunction in cardiovascular disease: Evidence for redox-based therapies

According to the latest Global Burden of Disease Study data, non-communicable diseases in general and cardiovascular disease (CVD) in particular are the leading cause of premature death and reduced quality of life. Demographic shifts, unhealthy lifestyles and a higher burden of adverse environmental factors provide an explanation for these findings. The expected growing prevalence of CVD requires enhanced research efforts for identification and characterisation of novel therapeutic targets and strategies. Cardiovascular risk factors including classical (e.g. hypertension, diabetes, hypercholesterolaemia) and non-classical (e.g. environmental stress) factors induce the development of endothelial dysfunction, which is closely associated with oxidant stress and vascular inflammation and results in CVD, particularly in older adults. Most classically successful therapies for CVD display vasoprotective, antioxidant and anti-inflammatory effects, but were originally designed with other therapeutic aims. So far, only a few 'redox drugs' are in clinical use and many antioxidant strategies have not met expectations. With the present review, we summarise the actual knowledge on CVD pathomechanisms, with special emphasis on endothelial dysfunction, adverse redox signalling and oxidative stress, highlighting the preclinical and clinical evidence. In addition, we provide a brief overview of established CVD therapies and their relation to endothelial dysfunction and oxidative stress. Finally, we discuss novel strategies for redox-based CVD therapies trying to explain why, despite a clear link between endothelial dysfunction and adverse redox signalling and oxidative stress, redox- and oxidative stress-based therapies have not yet provided a breakthrough in the treatment of endothelial dysfunction and CVD.

Targeting the NLRP3 inflammasome to reduce warm ischemic injury in donation after circulatory death heart

While the donation after circulatory death (DCD) heart transplantation is an emerging clinical practice, the primary source of donor hearts for transplantation remains donation after brain death (DBD) donors. DCD process induces formation of NOD-like receptor family pyrin domain containing-3 (NLRP3) inflammasome, a key mediator of inflammation-driven damage to heart. Inhibition of NLRP3 inflammasome formation could be protective to DCD hearts. Five groups (n = 8 each) of mice were studied-control beating heart donor (CBD) wild-type (WT), DCD WT, CBD NLRP3 knockout (KO), DCD NLRP3 KO, and DCD WT NLRP3 inhibitor group. Hearts were procured and reanimated on a Langendorff system to assess physiologic parameters and then for molecular assays. NLRP3 inhibitor (50 µmol/L) was administered to the DCD-NLRP3 inhibitor group at reanimation. Tissue NLRP3 levels were 80% higher in the DCD WT group compared with the CBD-WT group. Caspase-1 activity was significantly elevated in DCD WT but not in KO or NLRP3 inhibitor groups. The developed pressures and ±dP/dt were significantly impaired in the DCD WT group compared with the CBD-WT group, P < .05, but were well preserved in DCD-NLRP3 inhibitor group. The DCD process activates the NLRP3 inflammasome, contributing to myocardial damage and dysfunction. NLRP3 inflammasome inhibition limits myocardial injury and preserves DCD heart function.

Innate Immune Receptors, Key Actors in Cardiovascular Diseases

Cardiovascular diseases (CVDs) are the leading cause of death in the industrialized world. Most CVDs are associated with increased inflammation that arises mainly from innate immune system activation related to cardiac damage. Sustained activation of the innate immune system frequently results in maladaptive inflammatory responses that promote cardiovascular dysfunction and remodeling. Much research has focused on determining whether some mediators of the innate immune system are potential targets for CVD therapy. The innate immune system has specific receptors-termed pattern recognition receptors (PRRs)-that not only recognize pathogen-associated molecular patterns, but also sense danger-associated molecular signals. Activation of PRRs triggers the inflammatory response in different physiological systems, including the cardiovascular system. The classic PRRs, toll-like receptors (TLRs), and the more recently discovered nucleotide-binding oligomerization domain-like receptors (NLRs), have been recently proposed as key partners in the progression of several CVDs (e.g., atherosclerosis and heart failure). The present review discusses the key findings related to the involvement of TLRs and NLRs in the progression of several vascular and cardiac diseases, with a focus on whether some NLR subtypes (nucleotide-binding oligomerization domain, leucine rich repeat and pyrin domain-containing receptor 3 and nucleotide-binding oligomerization domain-containing protein 1) can be candidates for the development of new therapeutic strategies for several CVDs.

Therapeutic strategies for virus-negative myocarditis: a comprehensive review

Virus-negative or autoimmune myocarditis(VNM) is an inflammatory disease affecting the myocardium that may occur as a distinct disease with exclusive cardiac involvement, or in the context of systemic autoimmune or inflammatory disorders. The pathogenesis of VNM involves both innate and acquired immunity and is not completely elucidated: an early immune-mediated pathogenic process lead to subacute and chronic stages and eventually results in tissue remodeling, fibrosis, contractile dysfunction, dilated cardiomyopathy and arrhythmic burden, accounting for a dismal prognosis. Treatment interventions effectively curbing the acute inflammatory process at an early stage can prevent late cardiac remodeling and improve patient's outcome. The mainstay of treatment of VNM remains symptomatic therapy of heart failure and arrhythmia, while the use of immunosuppressive treatments has long been considered controversial until recently, and strategies effectively targeting the inflammatory and immune-mediated substrate of the disease remain elusive. Only steroids and azathioprine have been tested in clinical trials, and nowadays represent the therapy of choice. A substantial proportion of patients are resistant to first line strategies, suggesting that some critical inflammatory mechanisms are not responsive to conventional immunosuppression with steroids and azathioprine, or experience drug-related adverse events. Thus, second-line targeted therapeutic strategies to treat VNM are eagerly awaited. Recent data on the pathogenic mechanisms underlying myocardial inflammation are paving the way to novel, promising treatment strategies for myocarditis, which could reformulate future treatment strategies for VNM. In this review, we summarize the current therapeutic opportunities, beyond corticosteroids, to treat VNM, including conventional and biologic immunosuppressive drugs and cytokine blocking agents.

NLRP3 Inflammasome in Acute Myocardial Infarction

Acute myocardial infarction (AMI) is associated with the induction of a sterile inflammatory response that leads to further injury. The NACHT, leucine-rich repeat, and pyrin domain-containing protein 3 (NLRP3) inflammasome is a macromolecular structure responsible for the inflammatory response to injury or infection. NLRP3 can sense intracellular danger signals, such as ischemia and extracellular or intracellular alarmins during tissue injury. The NLRP3 inflammasome is primed and triggered by locally released damage-associated molecular patterns and amplifies the inflammatory response and cell death through caspase-1 activation. Here, we examine the scientific evidence supporting a role for NLRP3 in AMI and the available strategies to inhibit the effects of the inflammasome. Our focus is on the beneficial effects seen in experimental models of AMI in preclinical animal models and the initial results of clinical trials.

SGLT2 inhibition modulates NLRP3 inflammasome activity via ketones and insulin in diabetes with cardiovascular disease

Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce cardiovascular events in humans with type 2 diabetes (T2D); however, the underlying mechanism remains unclear. Activation of the NLR family, pyrin domain-containing 3 (NLRP3) inflammasome and subsequent interleukin (IL)-1β release induces atherosclerosis and heart failure. Here we show the effect of SGLT2 inhibitor empagliflozin on NLRP3 inflammasome activity. Patients with T2D and high cardiovascular risk receive SGLT2 inhibitor or sulfonylurea for 30 days, with NLRP3 inflammasome activation analyzed in macrophages. While the SGLT2 inhibitor's glucose-lowering capacity is similar to sulfonylurea, it shows a greater reduction in IL-1β secretion compared to sulfonylurea accompanied by increased serum β-hydroxybutyrate (BHB) and decreased serum insulin. Ex vivo experiments with macrophages verify the inhibitory effects of high BHB and low insulin levels on NLRP3 inflammasome activation. In conclusion, SGLT2 inhibitor attenuates NLRP3 inflammasome activation, which might help to explain its cardioprotective effects.

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.

Circulating interleukins in relation to coronary artery disease, atrial fibrillation and ischemic stroke and its subtypes: A two-sample Mendelian randomization study

Whether thyroid dysfunction plays a causal role in the development of cancer remains inconclusive. We conducted a two-sample Mendelian randomization study to investigate the associations between genetic predisposition to thyroid dysfunction and 22 site-specific cancers. Single-nucleotide polymorphisms associated with four traits of thyroid function were selected from a genome-wide association meta-analysis with up to 72,167 European-descent individuals. Summary-level data for breast cancer and 21 other cancers were extracted from the Breast Cancer Association Consortium (122,977 breast cancer cases and 105,974 controls) and UK Biobank (367,643 individuals). For breast cancer, a meta-analysis was performed using data from both sources. Genetically predicted thyroid dysfunction was associated with breast cancer, with similar patterns of associations in the Breast Cancer Association Consortium and UK Biobank. The combined odds ratios of breast cancer were 0.94 (0.91–0.98; p = 0.007) per genetically predicted one standard deviation increase in TSH levels, 0.96 (0.91–1.00; p = 0.053) for genetic predisposition to hypothyroidism, 1.04 (1.01–1.07; p = 0.005) for genetic predisposition to hyperthyroidism and 1.07 (1.02–1.12; p = 0.003) per genetically predicted one standard deviation increase in free thyroxine levels. Genetically predicted TSH levels and hypothyroidism were inversely with thyroid cancer; the odds ratios were 0.47 (0.30-0.73; p = 0.001) and 0.70 (0.51-0.98; p = 0.038), respectively. Our study provides evidence of a causal association between thyroid dysfunction and breast cancer (mainly ER-positive tumors) risk. The role of TSH and hypothyroidism for thyroid cancer and the associations between thyroid dysfunction and other cancers need further exploration.

The deleterious role of the prostaglandin E2 EP3 receptor in angiotensin II hypertension

Angiotensin II (ANG II) plays a key role in regulating blood pressure and inflammation. Prostaglandin E₂ (PGE₂) signals through four different G protein-coupled receptors, eliciting a variety of effects. We reported that activation of the EP₃ receptor reduces cardiac contractility. More recently, we have shown that overexpression of the EP₄ receptor is protective in a mouse myocardial infarction model. We hypothesize in this study that the relative abundance of EP₃ and EP₄ receptors is a major determinant of end-organ damage in the diseased heart. Thus EP₃ is detrimental to cardiac function and promotes inflammation, whereas antagonism of the EP₃ receptor is protective in an ANG II hypertension (HTN) model. To test our hypothesis, male 10- to 12-wk-old C57BL/6 mice were anesthetized with isoflurane and osmotic minipumps containing ANG II were implanted subcutaneously for 2 wk. We found that antagonism of the EP₃ receptor using L798,106 significantly attenuated the increase in blood pressure with ANG II infusion. Moreover, antagonism of the EP₃ receptor prevented a decline in cardiac function after ANG II treatment. We also found that 10- to 12-wk-old EP₃-transgenic mice, which overexpress EP₃ in the cardiomyocytes, have worsened cardiac function. In conclusion, activation or overexpression of EP₃ exacerbates end-organ damage in ANG II HTN. In contrast, antagonism of the EP₃ receptor is beneficial and reduces cardiac dysfunction, inflammation, and HTN.NEW & NOTEWORTHY This study is the first to show that systemic treatment with an EP₃ receptor antagonist (L798,106) attenuates the angiotensin II-induced increase in blood pressure in mice. The results from this project could complement existing hypertension therapies by combining blockade of the EP₃ receptor with antihypertensive drugs.

Porphyromonas gingivalis triggers the shedding of inflammatory endothelial microvesicles that act as autocrine effectors of endothelial dysfunction

A link between periodontitis and atherothrombosis has been highlighted. The aim of this study was to determine the influence of Porphyromonas gingivalis on endothelial microvesicles (EMV_Pg) shedding and their contribution to endothelial inflammation. Endothelial cells (EC) were infected with P. gingivalis (MOI = 100) for 24 h. EMV_Pg were isolated and their concentration was evaluated by prothrombinase assay. EMV_Pg were significantly increased in comparison with EMV_Ctrl shedded by unstimulated cells. While EMV_Ctrl from untreated EC had no effect, whereas, the proportion of apoptotic EC was increased by 30 nM EMV_Pg and viability was decreased down to 25%, a value elicited by P. gingivalis alone. Moreover, high concentration of EMV_Pg (30 nM) induced a pro-inflammatory and pro-oxidative cell response including up-regulation of TNF-α, IL-6 and IL-8 as well as an altered expression of iNOS and eNOS at both mRNA and protein level. An increase of VCAM-1 and ICAM-1 mRNA expression (4.5 folds and 3 folds respectively (p < 0.05 vs untreated) was also observed after EMV_Pg (30 nM) stimulation whereas P. gingivalis infection was less effective, suggesting a specific triggering by EMV_Pg. Kinasome analysis demonstrated the specific effect induced by EMV_Pg on main pro-inflammatory pathways including JNK/AKT and STAT. EMV_Pg are effective pro-inflammatory effectors that may have detrimental effect on vascular homeostasis and should be considered as potential autocrine and paracrine effectors involved in the link between periodontitis and atherothrombosis.

Sarcopenic Obesity in Heart Failure With Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) is a public health epidemic that is projected to double over the next two decades. Despite the high prevalence of HFpEF, there are currently no FDA approved therapies for health-related outcomes in this clinical syndrome making it one the greatest unmet needs in cardiovascular medicine. Aging and obesity are hallmarks of HFpEF and therefore there is a high incidence of sarcopenic obesity (SO) associated with this syndrome. The presence of SO in HFpEF patients is noteworthy as it is associated with co-morbidities, worsened cardiovascular health, hospitalizations, quality of life, and mortality. Furthermore, SO plays a central role in exercise intolerance, the most commonly reported clinical symptom of this condition. The aim of this review is to provide insights into the current knowledge pertaining to the contributing pathophysiological mechanisms and clinical outcomes associated with HFpEF-related SO. Current and prospective therapies to address SO in HFpEF, including lifestyle and pharmaceutical approaches, are discussed. The urgent need for future research aimed at better understanding the multifaceted physiological contributions to SO in HFpEF and implementing interventional strategies to specifically target SO is highlighted.

Interleukin-1 blockade in cardiovascular diseases: a clinical update

Interleukin-1 (IL-1) is the prototypical pro-inflammatory cytokine. IL-1 was implicated as a cardiodepressant factor in septic shock, and subsequent pre-clinical and clinical research has defined important roles for IL-1 in atherosclerosis, acute myocardial infarction (AMI), and heart failure (HF). IL-1 promotes the formation of the atherosclerotic plaque and facilitates its progression and complication. In a large phase III clinical trial of stable patients with prior AMI, blocking IL-1 activity using a monoclonal antibody prevented recurrent atherothrombotic cardiovascular events. IL-1 also contributes to adverse remodelling and left ventricular dysfunction after AMI, and in phase II studies, IL-1 blockade quenched the inflammatory response associated with ST-segment elevation AMI and prevented HF. In patients with established HF, IL-1 is thought to impair beta-adrenergic receptor signalling and intracellular calcium handling. Phase II studies in patients with HF show improved exercise capacity with IL-1 blockade. Thus, IL-1 blockade is poised to enter the clinical arena as an additional strategy to reduce the residual cardiovascular risk and/or address inflammatory cardiovascular conditions refractory to standard treatments. There are several IL-1 blockers available for clinical use, which differ in mechanism of action, and potentially also efficacy and safety. While IL-1 blockade is not immunosuppressive and not associated with opportunistic infections or an increased risk of cancer, fatal infections may occur more frequently while on treatment with IL-1 blockers likely due to a blunting of the inflammatory signs of infection leading to delayed presentation and diagnosis. We discuss the practical use of IL-1 blockade, including considerations for patient selection and safety monitoring.

Microvascular Dysfunction in Heart Failure With Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) is an increasingly studied entity accounting for 50% of all diagnosed heart failure and that has claimed its own dignity being markedly different from heart failure with reduced EF in terms of etiology and natural history (Graziani et al., 2018). Recently, a growing body of evidence points the finger toward microvascular dysfunction as the major determinant of the pathological cascade that justifies clinical manifestations (Crea et al., 2017). The high burden of comorbidities such as metabolic syndrome, hypertension, atrial fibrillation, chronic kidney disease, obstructive sleep apnea, and similar, could lead to a systemic inflammatory state that impacts the physiology of the endothelium and the perivascular environment, engaging complex molecular pathways that ultimately converge to myocardial fibrosis, stiffening, and dysfunction (Paulus and Tschope, 2013). These changes could even self-perpetrate with a positive feedback where hypoxia and locally released inflammatory cytokines trigger interstitial fibrosis and hypertrophy (Ohanyan et al., 2018). Identifying microvascular dysfunction both as the cause and the maintenance mechanism of this condition has opened the field to explore specific pharmacological targets like nitric oxide (NO) pathway, sarcomeric titin, transforming growth factor beta (TGF-β) pathway, immunomodulators or adenosine receptors, trying to tackle the endothelial impairment that lies in the background of this syndrome (Graziani et al., 2018;Lam et al., 2018). Yet, many questions remain, and the new data collected still lack a translation to improved treatment strategies. To further elaborate on this tangled and exponentially growing topic, we will review the evidence favoring a microvasculature-driven etiology of this condition, its clinical correlations, the proposed diagnostic workup, and the available/hypothesized therapeutic options to address microvascular dysfunction in the failing heart.

Outcomes of Acute Myocardial Infarction in Patients with Influenza and Other Viral Respiratory Infections

BACKGROUND

Acute influenza infection can trigger acute myocardial infarction, however, outcome of patients with acute myocardial infarction during influenza infection is largely unknown.

METHODS

Patients ≥18 years old with ST-elevation and non-ST-elevation myocardial infarction during January 2013-December 2014 were identified using the National Inpatient Sample. The clinical outcomes were compared among patients who had no respiratory infection to the ones with influenza and other viral respiratory infections using propensity score-matched analysis.

RESULTS

Of 1,884,985 admissions for acute myocardial infarction, acute influenza and other viral infections were diagnosed in 9,885 and 11,485 patients, respectively, accounting for 1.1% of patients. Acute myocardial infarction patients with concomitant influenza infection had a worse outcome than those with acute myocardial infarction alone, in terms of in-hospital case fatality rate, development of shock, acute respiratory failure, acute kidney injury, and higher rate of blood transfusion after propensity scores. The length of stay is also significantly longer in influenza patients with acute myocardial infarction, compared with patients with acute myocardial infarction alone. However, patients who developed acute myocardial infarction during other viral respiratory infection have a higher rate of acute respiratory failure but overall lower mortality rate, and are less likely to develop shock or require blood transfusion after propensity match. Despite presenting with acute myocardial infarction, less than one-fourth of patients with concomitant influenza infection underwent coronary angiography, but more than half (51.4%) required revascularization.

CONCLUSION

Influenza infection is associated with worse outcomes in acute myocardial infarction patients, and patients were less likely to receive further evaluation with invasive coronary angiography.

Electronegative LDL from Rabbits Fed with Atherogenic Diet Is Highly Proinflammatory

Electronegative low-density lipoprotein (LDL(-)) has been found in the plasma of familial hypercholesterolemia and acute myocardial infarction and has been implicated in atherosclerosis and cardiovascular disease. However, less is known about the involvement of LDL(-) in atherosclerosis-related inflammation. This study aims at investigating the inducibility of LDL(-) by atherogenic diet in rabbits and at exploring the proinflammatory potential of the diet-induced LDL(-) in macrophages. Rabbits were fed with an atherogenic diet; LDL was isolated from plasma by NaBr density gradient ultracentrifugation and was then resolved into nLDL and LDL(-) by anion-exchange chromatography. Isolated nLDL and LDL(-) were directly used or incubated with 10 μM CuSO₄ for 24 h to produce copper- (Cu-) ox-nLDL and Cu-ox-LDL(-). The effects of these LDLs on inflammation were evaluated in THP-1-derived macrophages. Macrophages were treated with nLDL, LDL(-), and extensively oxidized LDL (ox-LDL), then the levels of interleukin- (IL-) 1β, IL-6, and tumor necrosis factor- (TNF-) α in a culture medium were determined by ELISA, and the levels of total and phosphorylated IκB, p65, p38, JNK, and ERK in cell lysates were determined by Western blotting. The LDL(-) induced significantly higher levels of IL-1β, IL-6, and TNF-α in the medium. The levels of phosphorylated/total IκB, p65, p38, JNK, and ERK were also upregulated by LDL(-). In contrast, nLDL, Cu-ox-nLDL, and Cu-ox-LDL(-) exhibited much less effect. Knockdown of lectin-type oxidized LDL receptor- (LOX-) 1 resulted in significant reduction in LDL(-)-induced IL-1β, IL-6, and TNF-α. In addition, these LDL(-) effects were also markedly attenuated by inhibition of NF-κB and ERK1/2. The data suggested that LDL(-) induced inflammation through LOX-1-, NF-κB-, and ERK1/2-dependent pathways. Taken together, our results show that rabbits fed with atherogenic diet produce a highly proinflammatory LDL(-) that is more potent in inducing inflammation than nLDL and extensively oxidize LDL in macrophages. The results thus provide a novel link between diet-induced hypercholesterolemia and inflammation.

MCP-1 promotes detrimental cardiac physiology, pulmonary edema, and death in the cpk model of polycystic kidney disease

Polycystic kidney disease (PKD) is characterized by slowly expanding renal cysts that damage the kidney, typically resulting in renal failure by the fifth decade. The most common cause of death in these patients, however, is cardiovascular disease. Expanding cysts in PKD induce chronic kidney injury that is accompanied by immune cell infiltration, including macrophages, which we and others have shown can promote disease progression in PKD mouse models. Here, we show that monocyte chemoattractant protein-1 [MCP-1/chemokine (C-C motif) ligand 2 (CCL2)] is responsible for the majority of monocyte chemoattractant activity produced by renal PKD cells from both mice and humans. To test whether the absence of MCP-1 lowers renal macrophage concentration and slows disease progression, we generated genetic knockout (KO) of MCP-1 in a mouse model of PKD [congenital polycystic kidney (cpk) mice]. Cpk mice are born with rapidly expanding renal cysts, accompanied by a decline in kidney function and death by postnatal day 21. Here, we report that KO of MCP-1 in these mice increased survival, with some mice living past 3 mo. Surprisingly, however, there was no significant difference in renal macrophage concentration, nor was there improvement in cystic disease or kidney function. Examination of mice revealed cardiac hypertrophy in cpk mice, and measurement of cardiac electrical activity via ECG revealed repolarization abnormalities. MCP-1 KO did not affect the number of cardiac macrophages, nor did it alleviate the cardiac aberrancies. However, MCP-1 KO did prevent the development of pulmonary edema, which occurred in cpk mice, and promoted decreased resting heart rate and increased heart rate variability in both cpk and noncystic mice. These data suggest that in this mouse model of PKD, MCP-1 altered cardiac/pulmonary function and promoted death outside of its role as a macrophage chemoattractant.

Role of NLRP3 Inflammasome in Cardiac Inflammation and Remodeling after Myocardial Infarction

An accumulating body of evidence indicates that inflammation plays a crucial role in the pathophysiology of myocardial infarction (MI). Nucleotide-binding oligomerization domain-like receptor (NLR) family pyrin domain containing 3 (NLRP3) inflammasome is an intracellular multiprotein complex that regulates caspase-1 activation and the subsequent processing of the potent inflammatory cytokine interleukin (IL)-1β as well as triggering inflammatory cell death pyroptosis. We and other investigators demonstrated that deficiency of the NLRP3 inflammasome components reduces inflammation and improves cardiac dysfunction and remodeling in rodent models of MI. Therefore, the regulation of NLRP3 inflammasome has been regarded as a potential therapeutic target for MI. Furthermore, a recent Canakinumab Antiinflammatory Thrombosis Outcome Study (CANTOS) trial revealed the efficacy of IL-1β inhibition in preventing recurrent cardiovascular events in patients with MI. This review focuses on the role of NLRP3 inflammasome in the process of cardiac inflammation and remodeling after MI, and discusses its potential as a therapeutic target for the prevention and treatment of MI.

Inflammasome inhibition blocks cardiac glycoside cell toxicity

Chronic heart failure and cardiac arrhythmias have high morbidity and mortality, and drugs for the prevention and management of these diseases are a large part of the pharmaceutical market. Among these drugs are plant-derived cardiac glycosides, which have been used by various cultures over millennia as both medicines and poisons. We report that digoxin and related compounds activate the NLRP3 inflammasome in macrophages and cardiomyocytes at concentrations achievable during clinical use. Inflammasome activation initiates the maturation and release of the inflammatory cytokine IL-1β and the programmed cell death pathway pyroptosis in a caspase-1–dependent manner. Notably, the same fluxes of potassium and calcium cations that affect heart contraction also induce inflammasome activation in human but not murine cells. Pharmaceuticals that antagonize these fluxes, including glyburide and verapamil, also inhibit inflammasome activation by cardiac glycosides. Cardiac glycoside–induced cellular cytotoxicity and IL-1β signaling are likewise antagonized by inhibitors of the NLRP3 inflammasome or the IL-1 receptor–targeting biological agent anakinra. Our results inform on the molecular mechanism by which the inflammasome integrates the diverse signals that activate it through secondary signals like cation flux. Furthermore, this mechanism suggests a contribution of the inflammasome to the toxicity and adverse events associated with cardiac glycosides use in humans and that targeted anti-inflammatories could provide an additional adjunct therapeutic countermeasure.

Targeting Early Atherosclerosis: A Focus on Oxidative Stress and Inflammation

Atherosclerosis is a chronic vascular inflammatory disease associated to oxidative stress and endothelial dysfunction. Oxidation of low-density lipoprotein (LDL) cholesterol is one of the key factors for the development of atherosclerosis. Nonoxidized LDL have a low affinity for macrophages, so they are not themselves a risk factor. However, lowering LDL levels is a common clinical practice to reduce oxidation and the risk of major events in patients with cardiovascular diseases (CVD). Atherosclerosis starts with dysfunctional changes in the endothelium induced by disturbed shear stress which can lead to endothelial and platelet activation, adhesion of monocytes on the activated endothelium, and differentiation into proinflammatory macrophages, which increase the uptake of oxidized LDL (oxLDL) and turn into foam cells, exacerbating the inflammatory signalling. The atherosclerotic process is accelerated by a myriad of factors, such as the release of inflammatory chemokines and cytokines, the generation of reactive oxygen species (ROS), growth factors, and the proliferation of vascular smooth muscle cells. Inflammation and immunity are key factors for the development and complications of atherosclerosis, and therefore, the whole atherosclerotic process is a target for diagnosis and treatment. In this review, we focus on early stages of the disease and we address both biomarkers and therapeutic approaches currently available and under research.

Intracardiac administration of neutrophil protease cathepsin G activates noncanonical inflammasome pathway and promotes inflammation and pathological remodeling in non-injured heart

BACKGROUND

Inflammatory serine proteases (ISPs) play an important role in cardiac repair after injury through hydrolysis of dead cells and extracellular matrix (ECM) debris. Evidence also suggests an important role of ISPs in the coordination of the inflammatory response. However, the effect of ISPs on inflammation is obfuscated by the confounding factors associated with cell death and inflammatory cell infiltration induced after cardiac injury. This study investigated whether neutrophil-derived cathepsin G (Cat.G) influences inflammation and remodeling in the absence of prior cardiac injury and cell death.

METHODS AND RESULTS

Intracardiac catheter delivery of Cat.G (1 mg/kg) in rats induced significant left ventricular (LV) dilatation and cardiac contractile dysfunction at day 5, but not at day 2, post-delivery compared to vehicle-treated animals. Cat.G delivery also significantly increased matrix metalloprotease activity and collagen and fibronectin degradation at day 5 compared to vehicle-treated rats and these changes were associated with increased death signaling pathways and myocyte apoptosis. Mechanistic analysis shows that Cat.G-treatment induced potent chemotactic activity in hearts at day 2 and 5 post-delivery, characterized by processing and activation of interleukin (IL)-1β and IL-18, stimulation of inflammatory signaling pathways and accumulation of myeloid cells when compared to vehicle-treated rats. Cat.G-induced processing of IL-1β and IL-18 was independent of the canonical NLRP-3 inflammasome pathway and treatment of isolated cardiomyocytes with inhibitors of NLRP-3 or caspase-1 failed to reduce Cat.G-induced cardiomyocyte death. Notably, rats treated with IL-1 receptor antagonist (IL-1Ra) show reduced inflammation and improved cardiac remodeling and function following Cat.G delivery.

CONCLUSIONS

Cat.G exerts potent chemoattractant and pro-inflammatory effects in non-stressed or injured heart in part through processing and activation of IL-1 family cytokines, subsequently leading to adverse cardiac remodeling and function. Thus, targeting ISPs could be a novel therapeutic strategy to reduce cardiac inflammation and improve cardiac remodeling and function after injury or stress.

Fenofibrate attenuates cardiac and renal alterations in young salt-loaded spontaneously hypertensive stroke-prone rats through mitochondrial protection

OBJECTIVES

The simultaneous presence of cardiac and renal diseases is a pathological condition that leads to increased morbidity and mortality. Several lines of evidence have suggested that lipid dysmetabolism and mitochondrial dysfunction are pathways involved in the pathological processes affecting the heart and kidney. In the salt-loaded spontaneously hypertensive stroke-prone rat (SHRSP), a model of cardiac hypertrophy and nephropathy that shows mitochondrial alterations in the myocardium, we evaluated the cardiorenal effects of fenofibrate, a peroxisome proliferator-activated receptor alpha (PPARα) agonist that acts by modulating mitochondrial and peroxisomal fatty acid oxidation.

METHODS

Male SHRSPs aged 6-7 weeks were divided in three groups: standard diet (n = 6), Japanese diet with vehicle (n = 6), and Japanese diet with fenofibrate 150 mg/kg/day (n = 6) for 5 weeks. Cardiac and renal functions were assessed in vivo by MRI, ultrasonography, and biochemical assays. Mitochondria were investigated by transmission electron microscopy, succinate dehydrogenase (SDH) activity, and gene expression analysis.

RESULTS

Fenofibrate attenuated cardiac hypertrophy, as evidenced by histological and MRI analyses, and protected the kidneys, preventing morphological alterations, changes in arterial blood flow velocity, and increases in 24-h proteinuria. Cardiorenal inflammation, oxidative stress, and cellular senescence were also inhibited by fenofibrate. In salt-loaded SHRSPs, we observed severe morphological mitochondrial alterations, reduced SDH activity, and down-regulation of genes regulating mitochondrial fatty-acid oxidation (i.e. PPARα, SIRT3, and Acadm). These changes were counteracted by fenofibrate. In vitro, a direct protective effect of fenofibrate on mitochondrial membrane potential was observed in albumin-stimulated NRK-52E renal tubular epithelial cells.

CONCLUSION

The results suggest that the cardiorenal protective effects of fenofibrate in young male salt-loaded SHRSPs are explained by its capacity to preserve mitochondrial function.