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

The incidence and relative risk of major adverse cardiovascular events and hypertension in patients treated with immune checkpoint inhibitors plus tyrosine-kinase inhibitors for solid tumors: a systemic review and meta-analysis

INTRODUCTION

Combinations of immune checkpoint inhibitors (ICIs) and tyrosine kinase inhibitors (TKIs) can be responsible for major adverse cardiovascular events (MACEs). We performed a meta-analysis to assess the relative risk (RR) of MACEs and hypertension in cancer patients treated with ICI+TKI combinations.

RESEARCH DESIGN AND METHODS

We selected prospective trials through MEDLINE/PubMed, Cochrane Library, and ASCOMeeting abstracts. We calculated combined ORs, RRs, and 95% CIs using RevMansoftware for meta-analysis (v.5.2.3).

RESULTS

Seven studies were selected for the analysis of MACEs (3849 patients). The incidence MACEs were 0.8% with ICI+TKI combinations, compared to 0.2% in the control arms for both any- and high-grade. ICI+TKI combinations significantly increased the risk of any- (OR = 3.21; p = 0.01) and high-grade MACEs (OR = 2.72; p = 0.05). Ten studies were selected for the analysis of hypertension (5744 patients). The incidence of treatment-related hypertension of any-grade and high-grade was41.3% (vs. 20.8%) and 26.1% (vs. 12.3%) with ICI+TKI combinations, respectively. ICI+TKI combinations significantly increased the risk of treatment-related hypertension of any-grade (RR = 2.10; p = 0.001), but not of high-grade (p = 0.11).

CONCLUSIONS

ICI+TKI combinations increase the risk of MACEs compared to controls, although the absolute incidence is eventually low. Routine cardiovascular monitoring in asymptomatic patients is therefore not recommended.

B cell-mediated antigen presentation promotes adverse cardiac remodeling in chronic heart failure

Cardiovascular disease remains the leading cause of death worldwide. A primary driver of cardiovascular mortality is ischemic heart failure, a form of cardiac dysfunction that can develop in patients who survive myocardial infarction. Acute cardiac damage triggers robust changes in the spleen with rapid migration of immune cells from the spleen to the heart. Activating this "cardio-splenic" axis contributes to progressive cardiac dysfunction. The cardio-splenic axis has, therefore, been identified as a promising therapeutic target to prevent or treat heart failure. However, our understanding of the precise mechanisms by which specific immune cells contribute to adverse cardiac remodeling within the cardio-splenic axis remains limited. Here, we show that splenic B cells contribute to the development of heart failure via MHC II-mediated antigen presentation. We found that the adoptive transfer of splenic B cells from mice with ischemic heart failure promoted adverse cardiac remodeling and splenic inflammatory changes in naïve recipient mice. Based on single-cell RNA sequencing analysis of splenic B cells from mice with ischemic heart failure, we hypothesized that B cells contributed to adverse cardiac remodeling through antigen presentation by MHC II molecules. This mechanism was confirmed using transgenic mice with B cell-specific MHC II deletion, and by analyzing circulating B cells from humans who experienced myocardial infarction. Our results broaden our understanding of B lymphocyte biology, reshape current models of immune activation in response to myocardial injury, and point towards MHC II-mediated signaling in B cells as a novel and specific therapeutic target in chronic heart failure.

B cell-mediated antigen presentation promotes adverse cardiac remodeling in chronic heart failure

Cardiovascular disease remains the leading cause of death worldwide. A primary driver of cardiovascular mortality is ischemic heart failure, a form of cardiac dysfunction that can develop in patients who survive myocardial infarction. Acute cardiac damage triggers robust changes in the spleen with rapid migration of immune cells from the spleen to the heart. Activating this "cardio-splenic" axis contributes to progressive cardiac dysfunction. The cardio-splenic axis has, therefore, been identified as a promising therapeutic target to prevent or treat heart failure. However, our understanding of the precise mechanisms by which specific immune cells contribute to adverse cardiac remodeling within the cardio-splenic axis remains limited. Here, we show that splenic B cells contribute to the development of heart failure via MHC II-mediated antigen presentation. We found that the adoptive transfer of splenic B cells from mice with ischemic heart failure promoted adverse cardiac remodeling and splenic inflammatory changes in naïve recipient mice. Based on single-cell RNA sequencing analysis of splenic B cells from mice with ischemic heart failure, we hypothesized that B cells contributed to adverse cardiac remodeling through antigen presentation by MHC II molecules. This mechanism was confirmed using transgenic mice with B cell-specific MHC II deletion, and by analyzing circulating B cells from humans who experienced myocardial infarction. Our results broaden our understanding of B lymphocyte biology, reshape current models of immune activation in response to myocardial injury, and point towards MHC II-mediated signaling in B cells as a novel and specific therapeutic target in chronic heart failure.

Mechanism of fibroblast growth factor 21 in cardiac remodeling

Cardiac remodeling is a basic pathological process that enables the progression of multiple cardiac diseases to heart failure. Fibroblast growth factor 21 is considered a regulator in maintaining energy homeostasis and shows a positive role in preventing damage caused by cardiac diseases. This review mainly summarizes the effects and related mechanisms of fibroblast growth factor 21 on pathological processes associated with cardiac remodeling, based on a variety of cells of myocardial tissue. The possibility of Fibroblast growth factor 21 as a promising treatment for the cardiac remodeling process will also be discussed.

Druggable proteins influencing cardiac structure and function: Implications for heart failure therapies and cancer cardiotoxicity

Dysfunction of either the right or left ventricle can lead to heart failure (HF) and subsequent morbidity and mortality. We performed a genome-wide association study (GWAS) of 16 cardiac magnetic resonance (CMR) imaging measurements of biventricular function and structure. Cis-Mendelian randomization (MR) was used to identify plasma proteins associating with CMR traits as well as with any of the following cardiac outcomes: HF, non-ischemic cardiomyopathy, dilated cardiomyopathy (DCM), atrial fibrillation, or coronary heart disease. In total, 33 plasma proteins were prioritized, including repurposing candidates for DCM and/or HF: IL18R (providing indirect evidence for IL18), I17RA, GPC5, LAMC2, PA2GA, CD33, and SLAF7. In addition, 13 of the 25 druggable proteins (52%; 95% confidence interval, 0.31 to 0.72) could be mapped to compounds with known oncological indications or side effects. These findings provide leads to facilitate drug development for cardiac disease and suggest that cardiotoxicities of several cancer treatments might represent mechanism-based adverse effects.

Immune checkpoint inhibitor-related adverse cardiac events in patients with lung cancer: a systematic review and meta-analysis

Background

Although people are more and more aware of the cardiotoxicity caused by immune checkpoint inhibitors (ICIs) in the treatment of lung cancer, its incidence rate has not been systematically analyzed. This study aims to evaluate the incidence of cardiotoxicity related to the ICI therapies for lung cancer, so as to enhance clinicians' attention to cardiotoxicity, implement proper prevention and intervention for high-risk patients, and minimize the risk of cardiac dysfunction during and after completion of therapy.

Methods

We conducted a systematic literature search for relevant publications in PubMed and Scopus from inception to 19 April 2022. Pooled incidence and risk ratios with 95% confidence intervals (95% CIs) for cardiotoxicity events were calculated.

Results

A total of 37 studies covering 38 trials, including 14,342 patients, were identified. The pooled risk ratios of incidence of any cardiac AEs were 1.944 [95% CI 0.8–4.725] (Single ICI versus chemotherapy), 1.677 [95% CI 1.065–2.64] (Single ICI plus chemotherapy versus chemotherapy), and 0.478 [95% CI 0.127–1.798] (Single ICI versus Dual ICI). The incidence of myocarditis and arrhythmia were 0.003[95%CI 0.002–0.006] and 0.014[95%CI 0–0.037], respectively.

Conclusion

Single ICI did not increase the risk of cardiotoxicity compared with chemotherapy, and single ICI plus chemotherapy increased the risk of cardiotoxicity by 67% compared with chemotherapy alone. Combination immunotherapy did not increase the risk of cardiotoxicity compared with single ICI.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-022-02760-2.

Cardiotoxicity Induced by Immune Checkpoint Inhibitors: What a Cardio-Oncology Team Should Know and Do

Immune checkpoint inhibitors (ICIs) have revolutionized the therapeutic scenario for several malignancies. However, they can be responsible for immune-related adverse events (irAEs), involving several organs, with a pooled incidence ranging between 54% and 76%. The frequency of cardiovascular system involvement is <1%. Among the cardiovascular irAEs, myocarditis is the most common and the most dangerous but other, less common manifestations of ICI-related cardiotoxicity include pericardial disease, arrhythmias, Takotsubo-like syndrome, and acute myocardial infarction, all of which remain poorly explored. Both oncologists and cardiologists, as well as the patients, should be aware of the possible occurrence of one or more of these complications, which in some cases are fatal, in order to implement effective strategies of cardiac surveillance. In this review, we summarize the latest studies and recommendations on the pathogenesis, clinical manifestation, diagnosis, and management of ICI-related cardiotoxicity in order to realize a complete and updated overview on the main aspects of ICI-related cardiotoxicity, from surveillance to diagnosis to management, useful for both oncologists and cardiologists in their clinical practice. In particular, in the first part of the review, we realize a description of the pathogenetic mechanisms and risk factors of the main cardiovascular irAEs. Then, we focus on the management of ICI-related cardiotoxicity by analyzing five main points: (1) identifying and evaluating the type and severity of the cardiotoxicity; (2) deciding whether to withhold ICI therapy; (3) initiating steroid and immunosuppressive therapy; (4) starting conventional cardiac treatment; and (5) restarting ICI therapy. Finally, we discuss the existing evidence on surveillance for ICI-related cardiotoxicity and propose a surveillance strategy for both short- and long-term cardiotoxicity, according to the most recent guidelines.

Pro-Inflammatory Derangement of the Immuno-Interactome in Heart Failure

Chronic heart failure (HF) is a syndrome of heterogeneous etiology associated with multiple co-morbidities. Inflammation is increasingly recognized as a key contributor to the pathophysiology of HF. Heterogeneity and lack of data on the immune mechanism(s) contributing to HF may partially underlie the failure of clinical trials targeting inflammatory mediators. We studied the Immunome in HF cohort using mass cytometry and used data-driven systems immunology approach to discover and characterize modulated immune cell subsets from peripheral blood. We showed cytotoxic and inflammatory innate lymphoid and myeloid cells were expanded in HF patients compared to healthy controls. Network analysis showed highly modular and centralized immune cell architecture in healthy control immune cell network. In contrast, the HF immune cell network showed greater inter-cellular communication and less modular structure. Furthermore, we found, as an immune mechanism specific to HF with preserved ejection fraction (HFpEF), an increase in inflammatory MAIT and CD4 T cell subsets.

Immunometabolic Mechanisms of Heart Failure with Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) is increasing in prevalence worldwide, already accounting for at least half of all heart failure (HF). As most patients with HFpEF are obese with metabolic syndrome, metabolic stress has been implicated in syndrome pathogenesis. Recently, compelling evidence for bidirectional crosstalk between metabolic stress and chronic inflammation has emerged, and alterations in systemic and cardiac immune responses are held to participate in HFpEF pathophysiology. Indeed, based on both preclinical and clinical evidence, comorbidity-driven systemic inflammation, coupled with metabolic stress, have been implicated together in HFpEF pathogenesis. As metabolic alterations impact immune function(s) in HFpEF, major changes in immune cell metabolism are also recognized in HFpEF and in HFpEF-predisposing conditions. Both arms of immunity - innate and adaptive - are implicated in the cardiomyocyte response in HFpEF. Indeed, we submit that crosstalk among adipose tissue, the immune system, and the heart represents a critical component of HFpEF pathobiology. Here, we review recent evidence in support of immunometabolic mechanisms as drivers of HFpEF pathogenesis, discuss pivotal biological mechanisms underlying the syndrome, and highlight questions requiring additional inquiry.

The Diagnosis and Management of Immune Checkpoint Inhibitor Cardiovascular Toxicity: Myocarditis and Beyond

Recent years have brought major advancements in the use of immune therapy and specifically immune checkpoint inhibitors (ICIs) in cancer patients, with expanding indications for various malignancies resulting in the treatment of a large and increasing number of patients. While this therapy significantly improves outcomes in a variety of hematologic and solid tumors, the use of ICIs is associated with a substantial risk of immune-related adverse events. Cardiovascular toxicity, while not the most common side effect of ICIs, is associated with significant morbidity and mortality. It is therefore crucial for oncologists and cardiologists, as well as internists and emergency room physicians, to have a good understanding of this increasingly common clinical problem. In the present review, we discuss the cardiac aspects of ICI therapy with special emphasis on the clinical manifestations of their cardiovascular toxicity, diagnostic approaches, treatment and suggested surveillance.

Full-Length Transcriptome Sequencing: An Insight Into the Dog Model of Heart Failure

Heart failure (HF) leads to a progressive increase in morbidity and mortality rates. This study aimed to explore the transcriptional landscape during HF and identify differentially expressed transcripts (DETs) and alternative splicing events associated with HF. We generated a dog model of HF (n = 3) using right ventricular pacemaker implantation. We performed full-length transcriptome sequencing (based on nanopore platform) on the myocardial tissues and analyzed the transcripts using differential expression analysis and functional annotation methods [Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses]. Additionally, we estimated the expression of the selected genes by quantitative real-time PCR (qRT-PCR) and detected the proportion of immune cells using flow cytometry. We found that increased B-type natriuretic peptide reduced ejection fraction, and apparent clinical signs were observed in the dog model of HF. We identified 67,458 transcripts using full-length transcriptome sequencing. A total of 785 DETs were obtained from the HF and control groups. These DETs were mainly enriched in the immune responses, especially Th1, Th2, and Th17 cell differentiation processes. Furthermore, flow cytometry results revealed that the proportion of Th1 and Th17 cells increased in patients with HF compared to controls, while the proportion of Th2 cells decreased. Differentially expressed genes in the HF and control groups associated with Th1, Th2, and Th17 cell differentiation were quantified using qRT-PCR. We also identified variable splicing events of sarcomere genes (e.g., MYBPC3, TNNT2, TTN, FLNC, and TTNI3). In addition, we detected 4,892 transcription factors and 406 lncRNAs associated with HF. Our analysis based on full-length transcript sequencing provided an analysis perspective in a dog model of HF, which is valuable for molecular research in an increasingly relevant large animal model of HF.

Single-Cell Analysis Revealed the Role of CD8+ Effector T Cells in Preventing Cardioprotective Macrophage Differentiation in the Early Phase of Heart Failure

Heart failure is a complex clinical syndrome characterized by insufficient cardiac function. Heart-resident and infiltrated macrophages have been shown to play important roles in the cardiac remodeling that occurs in response to cardiac pressure overload. However, the possible roles of T cells in this process, have not been well characterized. Here we show that T cell depletion conferred late-stage heart protection but induced cardioprotective hypertrophy at an early stage of heart failure caused by cardiac pressure overload. Single-cell RNA sequencing analysis revealed that CD8+T cell depletion induced cardioprotective hypertrophy characterized with the expression of mitochondrial genes and growth factor receptor genes. CD8+T cells regulated the conversion of both cardiac-resident macrophages and infiltrated macrophages into cardioprotective macrophages expressing growth factor genes such as Areg, Osm, and Igf1, which have been shown to be essential for the myocardial adaptive response after cardiac pressure overload. Our results demonstrate a dynamic interplay between cardiac CD8+T cells and macrophages that is necessary for adaptation to cardiac stress, highlighting the homeostatic functions of resident and infiltrated macrophages in the heart.

Integrative Analyses of Genes Associated With Right Ventricular Cardiomyopathy Induced by Tricuspid Regurgitation

Tricuspid regurgitation (TR) induces right ventricular cardiomyopathy, a common heart disease, and eventually leads to severe heart failure and serious clinical complications. Accumulating evidence shows that long non-coding RNAs (lncRNAs) are involved in the pathological process of a variety of cardiovascular diseases. However, the regulatory mechanisms and functional roles of RNA interactions in TR-induced right ventricular cardiomyopathy are still unclear. Accordingly, we performed integrative analyses of genes associated with right ventricular cardiomyopathy induced by TR to study the roles of lncRNAs in the pathogenesis of this disease. In this study, we used high-throughput sequencing data of tissue samples from nine clinical cases of right ventricular myocardial cardiomyopathy induced by TR and nine controls with normal right ventricular myocardium from the Genotype-Tissue Expression database. We identified differentially expressed lncRNAs and constructed a protein-protein interaction and lncRNA-messenger RNA (mRNA) co-expression network. Furthermore, we determined hub lncRNA-mRNA modules related to right ventricular myocardial disease induced by TR and constructed a competitive endogenous RNA network for TR-induced right ventricular myocardial disease by integrating the interaction of lncRNA-miRNA-mRNA. In addition, we analyzed the immune infiltration using integrated data and the correlation of each immune-related gene with key genes of the integrated expression matrix. The present study identified 648 differentially expressed mRNAs, 201 differentially expressed miRNAs, and 163 differentially expressed lncRNAs. Protein-protein interaction network analysis confirmed that ADRA1A, AVPR1B, OPN4, IL-1B, IL-1A, CXCL4, ADCY2, CXCL12, GNB4, CCL20, CXCL8, and CXCL1 were hub genes. CTD-2314B22.3, hsa-miR-653-5p, and KIF17ceRNA; SRGAP3-AS2, hsa-miR-539-5p, and SHANK1; CERS6-AS1, hsa-miR-497-5p, and OPN4; INTS6-AS1, hsa-miR-4262, and NEURL1B; TTN-AS1, hsa-miR-376b-3p, and TRPM5; and DLX6-AS1, hsa-miR-346, and BIRC7 axes were obtained by constructing the ceRNA networks. Through the immune infiltration analysis, we found that the proportion of CD4 and CD8 T cells was about 20%, and the proportion of fibroblasts and endothelial cells was high. Our findings provide some insights into the mechanisms of RNA interaction in TR-induced right ventricular cardiomyopathy and suggest that lncRNAs are a potential therapeutic target for treating right ventricular myocardial disease induced by TR.

Isolevuglandin-Modified Cardiac Proteins Drive CD4+ T-Cell Activation in the Heart and Promote Cardiac Dysfunction

BACKGROUND

Despite the well-established association between T-cell-mediated inflammation and nonischemic heart failure, the specific mechanisms triggering T-cell activation during the progression of heart failure and the antigens involved are poorly understood. We hypothesized that myocardial oxidative stress induces the formation of isolevuglandin (IsoLG)-modified proteins that function as cardiac neoantigens to elicit CD4+ T-cell receptor (TCR) activation and promote heart failure.

METHODS

We used transverse aortic constriction in mice to trigger myocardial oxidative stress and T-cell infiltration. We profiled the TCR repertoire by mRNA sequencing of intramyocardial activated CD4+ T cells in Nur77^GFP reporter mice, which transiently express GFP on TCR engagement. We assessed the role of antigen presentation and TCR specificity in the development of cardiac dysfunction using antigen presentation-deficient MhcII^-/- mice and TCR transgenic OTII mice that lack specificity for endogenous antigens. We detected IsoLG protein adducts in failing human hearts. We also evaluated the role of reactive oxygen species and IsoLGs in eliciting T-cell immune responses in vivo by treating mice with the antioxidant TEMPOL and the IsoLG scavenger 2-hydroxybenzylamine during transverse aortic constriction, and ex vivo in mechanistic studies of CD4+ T-cell proliferation in response to IsoLG-modified cardiac proteins.

RESULTS

We discovered that TCR antigen recognition increases in the left ventricle as cardiac dysfunction progresses and identified a limited repertoire of activated CD4+ T-cell clonotypes in the left ventricle. Antigen presentation of endogenous antigens was required to develop cardiac dysfunction because MhcII^-/- mice reconstituted with CD4+ T cells and OTII mice immunized with their cognate antigen were protected from transverse aortic constriction-induced cardiac dysfunction despite the presence of left ventricle-infiltrated CD4+ T cells. Scavenging IsoLGs with 2-hydroxybenzylamine reduced TCR activation and prevented cardiac dysfunction. Mechanistically, cardiac pressure overload resulted in reactive oxygen species-dependent dendritic cell accumulation of IsoLG protein adducts, which induced robust CD4+ T-cell proliferation.

CONCLUSIONS

Our study demonstrates an important role of reactive oxygen species-induced formation of IsoLG-modified cardiac neoantigens that lead to TCR-dependent CD4+ T-cell activation within the heart.

Antioxidant and anti‑inflammatory mechanisms of action of astaxanthin in cardiovascular diseases (Review)

Cardiovascular diseases are the most common cause of mortality worldwide. Oxidative stress and inflammation are pathophysiological processes involved in the development of cardiovascular diseases; thus, anti‑inflammatory and antioxidant agents that modulate redox balance have become research targets so as to evaluate their molecular mechanisms of action and therapeutic properties. Astaxanthin, a carotenoid of the xanthophyll group, has potent antioxidant properties due to its molecular structure and its arrangement in the plasma membrane, factors that favor the neutralization of reactive oxygen and nitrogen species. This carotenoid also has prominent anti‑inflammatory activity, possibly interrelated with its antioxidant effect, and is also involved in the modulation of lipid and glucose metabolism. Considering the potential beneficial effects of astaxanthin on cardiovascular health evidenced by preclinical and clinical studies, the aim of the present review was to describe the molecular and cellular mechanisms associated with the antioxidant and anti‑inflammatory properties of this carotenoid in cardiovascular diseases, particularly atherosclerosis. The beneficial properties and safety profile of astaxanthin indicate that this compound may be used for preventing progression or as an adjuvant in the treatment of cardiovascular diseases.

PD-1/PDL-1 Inhibitors and Cardiotoxicity; Molecular, Etiological and Management Outlines

Background

The US Food and Drug Administration (FDA) has approved several immunotherapeutic drugs for cancer since 2010, and many more are still being evaluated in other clinical studies. These inhibitors significantly increase response rates and result in the treatment of patients with advanced cancer. However, cancer immunotherapy leads to essential cardiac toxicity properties that have become distinct from other cancer patients' care and are mostly related to their etiology.

Aim of review

As potential implications, the occurrence of cardiovascular adverse events is particularly challenging and needs a comprehensive understanding of overall cancer-related etiology, clinical outcomes with different variable severity, and management.

Key scientific concepts of review

In terms of improving the overall survival of patients with cancer, clinicians should be careful in selecting either programmed cell death-1 (PD-1) or its programmed cell death ligand (PDL-1) inhibitors by evaluating their risk and clinical benefit for early intervention and decrease the level of morbidity and mortality of their patients. This review focuses on the effectiveness of PD-1/PL-1 antibodies and associated cardiotoxicity adverse events, including etiological mechanisms, diagnosis, and treatment.

Adaptive immune disorders in hypertension and heart failure: focusing on T-cell subset activation and clinical implications

: Hypertension is a growing health concern worldwide. Established hypertension is a causative factor of heart failure, which is characterized by increased vascular resistance and intractable uncontrolled blood pressure. Hypertension and heart failure have multiple causes and complex pathophysiology but cellular immunity is thought to contribute to the development of both. Recent studies showed that T cells play critical roles in hypertension and heart failure in humans and animals, with various stimuli leading to the formation of effector T cells that infiltrate the cardiovascular wall. Monocytes/macrophages also accumulate in the cardiovascular wall. Various cytokines (e.g. interleukin-6, interleukin-17, interleukin-10, tumor necrosis factor-α, and interferon-γ) released from immune cells of various subtypes promote vascular senescence and elastic laminal degradation as well as cardiac fibrosis and/or hypertrophy, leading to cardiovascular structural alterations and dysfunction. Recent laboratory evidence has defined a link between inflammation and the immune system in initiation and progression of hypertension and heart failure. Moreover, cross-talk among natural killer cells, adaptive immune cells (T cells and B cells), and innate immune cells (i.e. monocytes, macrophages, neutrophils, and dendritic cells) contributes to end-cardiovasculature damage and dysfunction in hypertension and heart failure. Clinical and experimental studies on the diagnostic potential of T-cell subsets revealed that blood regulatory T cells, CD4 cells, CD8 T cells, and the ratio of CD4 to CD8 T cells show promise as biomarkers of hypertension and heart failure. Therapeutic interventions to suppress activation of these cells may prove beneficial in reducing end-organ damage and preventing consequences of cardiovascular failure, including hypertension of heart failure.

Immune Checkpoint Inhibitors and Cardiac Toxicity in Patients Treated for Non-Small Lung Cancer: A Review

Lung cancer is a major cause of cancer-related mortality worldwide, both in men and women. The vast majority of patients are diagnosed with non-small-cell lung cancer (NSCLC, 80-85% of lung cancer cases). Therapeutics named immune checkpoint inhibitors (ICIs) have revolutionized cancer treatment in the last decade. They are monoclonal antibodies, and those directed against PD-1 (programmed cell death protein 1) or PD-L1 (programmed cell death-ligand 1) have been used in the treatment of lung cancer and significantly improved the prognosis of NSCLC patients. However, during treatment with ICIs, immune-related adverse events (irAEs) can occur in any organ and any tissue. At the same time, although cardiac irAEs are relatively rare compared to irAEs in other organs, they have a high mortality rate. The two most common clinical manifestations of immunotherapy-related cardiotoxicity are myocarditis and pericarditis. Various types of arrhythmias have been reported in patients treated with ICIs, including the occurrence of life-threatening complete atrioventricular block or ventricular tachyarrhythmias. Here, we aim to summarize the incidence, clinical manifestations, underlying mechanisms, diagnosis, and treatment strategies for ICI-associated cardiotoxicity as these issues become very important in view of the increasing use of ICI in the treatment of lung cancer.

Dietary L-Tryptophan Regulates Colonic Serotonin Homeostasis in Mice with Dextran Sodium Sulfate-Induced Colitis

BACKGROUND

L-tryptophan (Trp) has been reported to regulate gut immune responses during inflammation. However, the underlying mechanisms are largely unknown.

OBJECTIVE

We investigated the role of Trp supplementation on the serotonin receptor (HTR)-mediated immune response in the colon of mice with dextran sodium sulfate (DSS)-induced colitis.

METHODS

In Experiment 1, male C57BL/6 mice were randomly assigned to 1 of 4 groups: Control (Con) or L-Trp supplementation [0.1 mg/(g body weight·d) in drinking water] (Trp) with (+DSS) or without 2% DSS in drinking water from days 8 to 14 of the 17-d study. In Experiments 2 and 3, Trp + DSS (Expt. 2) or DSS (Expt. 3) mice were treated as described above and subcutaneously administered with HTR1A or HTR4 antagonists (or their combination) or an HTR2 agonist from days 8 to 14 of the 15-d study. Changes in immune cell phenotypes, inflammatory mediators, and related cell signaling molecules were assessed by flow cytometry, real-time PCR, or Western blot. The mRNA abundances of Trp hydroxylase (Tph1), serotonin reuptake transporter (Slc6a4), and Htr in the colon were also assessed.

RESULTS

Trp supplementation before DSS treatment upregulated the expression of colonic Slc6a4 (0.49 compared with 0.30), Htr1a (1.14 compared with 0.65), and Htr4 (1.08 compared with 0.70), downregulated the expression of Htr2a (1.54 compared with 1.89), and decreased the colonic serotonin concentration (11.5 compared with 14.8 nmol/g tissue) (P < 0.01). Trp regulated the DSS-induced immune response partly through attenuating the activation of toll-like receptor 4 (TLR4)-STAT3 signaling and nucleus p-65. Either an HTR2 agonist or HTR1A and HTR4 antagonists reversed the effects of Trp.

CONCLUSIONS

In mice treated with DSS, Trp supplementation before DSS administration improved colonic immune responses partly by reducing colonic serotonin and subsequent interactions with HTR1A and HTR4, which are known to be present on neutrophils and macrophages.

Defective Mitochondrial Cardiolipin Remodeling Dampens HIF-1α Expression in Hypoxia

Mitochondria fulfill vital metabolic functions and act as crucial cellular signaling hubs, integrating their metabolic status into the cellular context. Here, we show that defective cardiolipin remodeling, upon loss of the cardiolipin acyl transferase tafazzin, decreases HIF-1α signaling in hypoxia. Tafazzin deficiency does not affect posttranslational HIF-1α regulation but rather HIF-1α gene expression, a dysfunction recapitulated in iPSC-derived cardiomyocytes from Barth syndrome patients with tafazzin deficiency. RNA-seq analyses confirmed drastically altered signaling in tafazzin mutant cells. In hypoxia, tafazzin-deficient cells display reduced production of reactive oxygen species (ROS) perturbing NF-κB activation and concomitantly HIF-1α gene expression. Tafazzin-deficient mice hearts display reduced HIF-1α levels and undergo maladaptive hypertrophy with heart failure in response to pressure overload challenge. We conclude that defective mitochondrial cardiolipin remodeling dampens HIF-1α signaling due to a lack of NF-κB activation through reduced mitochondrial ROS production, decreasing HIF-1α transcription.

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Defective remodeling of mitochondrial cardiolipin dampens HIF-1α signaling

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ROS-mediated NF-κB activation is impaired in cardiolipin-deficient cells

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Defective NF-κB-mediated HIF-1α gene induction decreases the cellular response to hypoxia

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Deregulated cardiac response to pressure overload in Barth syndrome mouse

New Approaches to Target Inflammation in Heart Failure: Harnessing Insights from Studies of Immune Cell Diversity

Despite mounting evidence implicating inflammation in cardiovascular diseases, attempts at clinical translation have shown mixed results. Recent preclinical studies have reenergized this field and provided new insights into how to favorably modulate cardiac macrophage function in the context of acute myocardial injury and chronic disease. In this review, we discuss the origins and roles of cardiac macrophage populations in the steady-state and diseased heart, focusing on the human heart and mouse models of ischemia, hypertensive heart disease, and aortic stenosis. Specific attention is given to delineating the roles of tissue-resident and recruited monocyte-derived macrophage subsets. We also highlight emerging concepts of monocyte plasticity and heterogeneity among monocyte-derived macrophages, describe possible mechanisms by which infiltrating monocytes acquire unique macrophage fates, and discuss the putative impact of these populations on cardiac remodeling. Finally, we discuss strategies to target inflammatory macrophage populations.

[Curing cancer and protecting the heart : Challenges in cardio-oncology in the era of modern tumor treatment]

Recent advances in the medical oncological treatment options for cancer have led to a clear improvement in the survival rate worldwide; however, many of the recently developed new drugs are directly or indirectly associated with cardiovascular side effects. Cardiovascular diseases are already the most frequent non-cancerous cause of death in tumor patients. Prevention, early detection of these complications, correct management and timely initiation of specific cardiac medical treatment are the key for an improvement of the cardiovascular prognosis. This article provides an overview and comprehensive summary of the possible cardiotoxic side effects of important oncological therapies and offers possible practical strategies with respect to risk stratification, cardiological follow-up care and management approaches for chemotherapy-induced left ventricular dysfunction.

Heart Inflammation: Immune Cell Roles and Roads to the Heart

Heart failure (HF) has been traditionally viewed as a disease of the cardiac muscle associated with systemic inflammation. Burgeoning evidence implicates immune effector mechanisms that include immune cell activation and trafficking to the heart. Immune cell infiltration in the myocardium can have adverse effects in the heart and contribute to the pathogenesis of HF. Both innate and adaptive immunity operate sequentially, and the specificity of these responses depends on the initial trigger sensed by the heart. Although the role of the immune system in the initial inflammatory response to infection and injury is well studied, what sets the trajectory to HF from different etiologies and the role of immunity once HF has been established is less understood. Herein, we review experimental and clinical knowledge of cardiac inflammation induced by different triggers that often result in HF from different etiologies. We focus on the mechanisms of immune cell activation systemically and on the pathways immune cells use to traffic to the heart.

T-cell recruitment to the heart: friendly guests or unwelcome visitors?

Myocardial inflammation can lead to lethal acute or chronic heart failure (HF). T lymphocytes (T cells), have been reported in the inflamed heart in different etiologies of HF, and more recent studies support that different T-cell subsets play distinct roles in the heart depending on the inflammation-triggering event. T cells follow sequential steps to extravasate into tissues, but their specific recruitment to the heart is determined by several factors. These include differences in T-cell responsiveness to specific chemokines in the heart environment, as well as differences in the expression of adhesion molecules in response to distinct stimuli, which regulate T-cell recruitment to the heart and have consequences in cardiac remodeling and function. This review focuses on recent advances in our understanding of the role T cells play in the heart, including its critical role for host defense to virus and myocardial healing postischemia, and its pathogenic role in chronic ischemic and nonischemic HF. We discuss a variety of mechanisms that contribute to the inflammatory damage to the heart, as well as regulatory mechanisms that limit the magnitude of T-cell-mediated inflammation. We also highlight areas in which further research is needed to understand the role T cells play in the heart and distinguish the findings reported in experimental animal models and how they may translate to clinical observations in the human heart.

Immune checkpoint inhibitors and cardiovascular toxicity

Immune checkpoint inhibitors are a new class of anticancer therapies that amplify T-cell-mediated immune responses against cancer cells. Immune checkpoint inhibitors have shown important benefits in phase 3 trials, and several agents have been approved for specific malignancies. Although adverse events from immune checkpoint inhibitors are a common occurrence, cardiotoxic effects are uncommon, but are often serious complications with a relatively high mortality. Most cardiotoxic effects appear to be inflammatory in nature. Clinical assessment of a combination of biomarkers, electrocardiography, cardiac imaging, and endomyocardial biopsy can be used to confirm a possible diagnosis. In this Review, we discuss the epidemiology of immune checkpoint inhibitor-mediated cardiotoxic effects, as well as their clinical presentation, subtypes, risk factors, pathophysiology, and clinical management, including the introduction of a new surveillance strategy.

CD8+-T Cells With Specificity for a Model Antigen in Cardiomyocytes Can Become Activated After Transverse Aortic Constriction but Do Not Accelerate Progression to Heart Failure

Heart failure due to pressure overload is frequently associated with inflammation. In addition to inflammatory responses of the innate immune system, autoimmune reactions of the adaptive immune system appear to be triggered in subgroups of patients with heart failure as demonstrated by the presence of autoantibodies against myocardial antigens. Moreover, T cell-deficient and T cell-depleted mice have been reported to be protected from heart failure induced by transverse aortic constriction (TAC) and we have shown recently that CD4⁺-helper T cells with specificity for an antigen in cardiomyocytes accelerate TAC-induced heart failure. In this study, we set out to investigate the potential contribution of CD8⁺-cytotoxic T cells with specificity to a model antigen (ovalbumin, OVA) in cardiomyocytes to pressure overload-induced heart failure. In 78% of cMy-mOVA mice with cardiomyocyte-specific OVA expression, a low-grade OVA-specific cellular cytotoxicity was detected after TAC. Adoptive transfer of OVA-specific CD8⁺-T cells from T cell receptor transgenic OT-I mice before TAC did not increase the risk of OVA-specific autoimmunity in cMy-mOVA mice. After TAC, again 78% of the mice displayed an OVA-specific cytotoxicity with on average only a three-fold higher killing of OVA-expressing target cells. More CD8⁺ cells were present after TAC in the myocardium of cMy-mOVA mice with OT-I T cells (on average 17.5/mm²) than in mice that did not receive OVA-specific CD8⁺-T cells (3.6/mm²). However, the extent of fibrosis was similar in both groups. Functionally, as determined by echocardiography, the adoptive transfer of OVA-specific CD8⁺-T cells did not significantly accelerate the progression from hypertrophy to heart failure in cMy-mOVA mice. These findings argue therefore against a major impact of cytotoxic T cells with specificity for autoantigens of cardiomyocytes in pressure overload-induced heart failure.

NFATc3 deficiency reduces the classical activation of adipose tissue macrophages

Nuclear factors of activated T cells (NFAT) c3 have a prominent role in the regulation of proinflammatory factors in immune cells. The classically activated M1 macrophages are key players in the initiation and maintenance of adipose tissue (AT) inflammation. The role of NFATc3 in obesity and AT inflammation is unknown. We set out to determine how deficiency of NFATc3 effected macrophage polarization, inflammation and insulin resistance in visceral AT of high-fat diet (HFD)-fed mice. Nfatc3−/− and WT mice were fed a HFD for 8–17 weeks. Epididymal white AT (eWAT) F4/80(+) cells were characterized by fluorescence-activated cell sorting and quantitative RT-PCR. Results showed that Nfatc3−/− mice developed HFD-induced obesity similar to WT mice, but insulin sensitivity and glucose tolerance were improved, and liver fat accumulation was reduced in Nfatc3−/− mice compared to WT control mice. Moreover, M1 macrophage content and proinflammatory factors were reduced, whereas the alternatively activated M2 macrophage content was increased in eWAT of HFD-fed Nfatc3−/− mice compared to that of WT mice. In addition, eWAT insulin signaling was improved in HFD-fed Nfatc3−/− mice. Importantly, after bone-marrow-derived macrophages had been isolated from Nfatc3−/− mice and cultured in vitro, treatment of these cells with interferon-γ and lipopolysaccharide resulted in reduction of M1 inflammatory markers, suggesting that NFATc3 promoted M1 polarization by a cell-autonomous mechanism. The results demonstrated that NFATc3 played an important role in M1 macrophage polarization, AT inflammation and insulin resistance in response to obesity through transcriptional activation of proinflammatory genes.