Heart failure as interstitial cancer: emergence of a malignant fibroblast phenotype

Cardiac sympathetic overdrive, M2 macrophage activation and fibroblast heterogeneity are associated with cardiac remodeling in a chronic pressure overload rat model of HFpEF

Heart failure with preserved ejection fraction (HFpEF) is a multifaceted pathogenesis disease and the exact mechanisms driving HFpEF have not been completely elucidated. Pressure overload hypertrophy (POH) related fibroblasts and M2 macrophages in HFpEF myocardium have been recently identified and are now of great interest. Sympathetic overdrive has also been implicated in HFpEF. This study is designed to dynamically observe the potential roles of aforementioned mechanisms in pathological remodeling and cardiac dysfunction in chronic PO rats. Surgical constriction of the abdominal aorta was used for induction of HFpEF. Echocardiography, electrocardiogram, hemodynamic measurement, hematoxylin and eosin staining, Masson staining, immunohistochemistry and immunofluorescence were performed to assess the changes in heart dysfunction, cardiac remodeling and driving mechanisms at different time points (2, 18, 24 weeks). The PO induced HFpEF model was well established, which was confirmed by the persistent increase in carotid artery systolic and diastolic blood pressure, and left ventricle hypertrophy at the corresponding postoperative stage. Meanwhile, PO hypertrophy gradually developed into HFpEF, associated with QT and QTc intervals prolongation, normal systolic (EF was maintained at >50%) but impaired diastolic function (increasing LVEDP and LV -dP/dtmin, abnormal E/A ratio), increased myocytes size, and observed relatively slight inflammatory infiltration but robust reactive fibrosis. IHC staining further confirmed that macrophages (CD68) but not neutrophils (MPO) or T cells (CD3) accounted for a predominant proportion of infiltrating cells. Mechanistically, we found that the infiltrating macrophages in the heart expressed high levels of CD206 which was simultaneously adjacent to POH fibroblasts appeared to overexpression of α-SMA in PO rats at late stages. Interestingly, we distinguished two different POHF sub-populations during PO induced HFpEF development, according to non overlapping signals of α-SMA and PDGFRα/β proteins. Additionally, PO led to a pronounced exaggeration in sympathetic fibers at all time points. These findings suggest that the establishing model here begins with cardiac sympathetic overdrive, subsequently along with immune cells especially M2 macrophage accumulation and fibroblast heterogeneity at later stages is associated with the development of cardiac maladaptive remodeling and diastolic dysfunction thus further progression to HFpEF.

Fibroblast activation protein: Pivoting cancer/chemotherapeutic insight towards heart failure

An important mechanism for cancer progression is degradation of the extracellular matrix (ECM) which is accompanied by the emergence and proliferation of an activated fibroblast, termed the cancer associated fibroblast (CAF). More specifically, an enzyme pathway identified to be amplified with local cancer progression and proliferation of the CAF, is fibroblast activation protein (FAP). The development and progression of heart failure (HF) irrespective of the etiology is associated with left ventricular (LV) remodeling and changes in ECM structure and function. As with cancer, HF progression is associated with a change in LV myocardial fibroblast growth and function, and expresses a protein signature not dissimilar to the CAF. The overall goal of this review is to put forward the postulate that scientific discoveries regarding FAP in cancer as well as the development of specific chemotherapeutics could be pivoted to target the emergence of FAP in the activated fibroblast subtype and thus hold translationally relevant diagnostic and therapeutic targets in HF.

Integrin beta-like 1 mediates fibroblast-cardiomyocyte crosstalk to promote cardiac fibrosis and hypertrophy

AIMS

Crosstalk between fibroblasts and cardiomyocytes (CMs) plays a critical role in cardiac remodelling during heart failure (HF); however, the underlying molecular mechanisms remain obscure. Recently, a secretory protein, Integrin beta-like 1 (ITGBL1) was revealed to have detrimental effects on several diseases, such as tumours, pulmonary fibrosis, and hepatic fibrosis; whereas the effect of ITGBL1 on HF is unclear. The purpose of this study was to evaluate its contribution to volume overload-induced remodelling.

METHODS AND RESULTS

In this study, we identified ITGBL1 was highly expressed in varied heart diseases and validated in our TAC mice model, especially in fibroblasts. To investigate the role of ITGBL1 in in vitro cell experiments, neonatal rat fibroblasts (NRCFs) and cardiomyocytes (NRCMs) were performed for further study. We found that in comparison to NRCMs, NRCFs expressed high levels of ITGBL1. Meanwhile, ITGBL1 was upregulated in NRCFs, but not in NRCMs following angiotensin-II (AngII) or phenylephrine stimulation. Furthermore, ITGBL1 overexpression promoted NRCFs activation, whereas knockdown of ITGBL1 alleviated NRCFs activation under AngII treatment. Moreover, NRCFs-secreted ITGBL1 could induce NRCMs hypertrophy. Mechanically, ITGBL1-NME/NM23 nucleoside diphosphate kinase 1 (NME1)-TGF-β-Smad2/3 and Wnt signalling pathways were identified to mediate NRCFs activation and NRCMs hypertrophy, respectively. Finally, the knockdown of ITGBL1 in mice subjected to transverse aortic constriction (TAC) surgery recapitulated the in vitro findings, demonstrating blunted cardiac fibrosis, hypertrophy, and improved cardiac function.

CONCLUSIONS

ITGBL1 is an important functional mediator between fibroblast-cardiomyocyte crosstalk and could be an effective target for cardiac remodelling in HF patients.

Porcupine inhibitor CGX1321 alleviates heart failure with preserved ejection fraction in mice by blocking WNT signaling

Heart failure with preserved ejection fraction (HFpEF) is highly prevalent, and lacks effective treatment. The aberration of WNT pathway underlies many pathological processes including cardiac fibrosis and hypertrophy, while porcupine is an acyltransferase essential for the secretion of WNT ligands. In this study we investigated the role of WNT signaling pathway in HFpEF as well as whether blocking WNT signaling by a novel porcupine inhibitor CGX1321 alleviated HFpEF. We established two experimental HFpEF mouse models, namely the UNX/DOCA model and high fat diet/L-NAME ("two-hit") model. The UNX/DOCA and "two-hit" mice were treated with CGX1321 (3 mg·kg-1·d-1) for 4 and 10 weeks, respectively. We showed that CGX1321 treatment significantly alleviated cardiac hypertrophy and fibrosis, thereby improving cardiac diastolic function and exercise performance in both models. Furthermore, both canonical and non-canonical WNT signaling pathways were activated, and most WNT proteins, especially WNT3a and WNT5a, were upregulated during the development of HEpEF in mice. CGX1321 treatment inhibited the secretion of WNT ligands and repressed both canonical and non-canonical WNT pathways, evidenced by the reduced phosphorylation of c-Jun and the nuclear translocation of β-catenin and NFATc3. In an in vitro HFpEF model, MCM and ISO-treated cardiomyocytes, knockdown of porcupine by siRNA leads to a similar inhibitory effect on WNT pathways, cardiomyocyte hypertrophy and cardiac fibroblast activation as CGX1321 did, whereas supplementation of WNT3a and WNT5a reversed the anti-hypertrophy and anti-fibrosis effect of CGX1321. We conclude that WNT signaling activation plays an essential role in the pathogenesis of HFpEF, and porcupine inhibitor CGX1321 exerts a therapeutic effect on HFpEF in mice by attenuating cardiac hypertrophy, alleviating cardiac fibrosis and improving cardiac diastolic function.

CRISPR-Cas9 editing of TLR4 to improve the outcome of cardiac cell therapy

Inflammation and fibrosis limit the reparative properties of human mesenchymal stromal cells (hMSCs). We hypothesized that disrupting the toll-like receptor 4 (TLR4) gene would switch hMSCs toward a reparative phenotype and improve the outcome of cell therapy for infarct repair. We developed and optimized an improved electroporation protocol for CRISPR-Cas9 gene editing. This protocol achieved a 68% success rate when applied to isolated hMSCs from the heart and epicardial fat of patients with ischemic heart disease. While cell editing lowered TLR4 expression in hMSCs, it did not affect classical markers of hMSCs, proliferation, and migration rate. Protein mass spectrometry analysis revealed that edited cells secreted fewer proteins involved in inflammation. Analysis of biological processes revealed that TLR4 editing reduced processes linked to inflammation and extracellular organization. Furthermore, edited cells expressed less NF-ƙB and secreted lower amounts of extracellular vesicles and pro-inflammatory and pro-fibrotic cytokines than unedited hMSCs. Cell therapy with both edited and unedited hMSCs improved survival, left ventricular remodeling, and cardiac function after myocardial infarction (MI) in mice. Postmortem histologic analysis revealed clusters of edited cells that survived in the scar tissue 28 days after MI. Morphometric analysis showed that implantation of edited cells increased the area of myocardial islands in the scar tissue, reduced the occurrence of transmural scar, increased scar thickness, and decreased expansion index. We show, for the first time, that CRISPR-Cas9-based disruption of the TLR4-gene reduces pro-inflammatory polarization of hMSCs and improves infarct healing and remodeling in mice. Our results provide a new approach to improving the outcomes of cell therapy for cardiovascular diseases.

Inhibition of long noncoding RNA Gm41724 alleviates pressure overload-induced cardiac fibrosis by regulating lamina-associated polypeptide 2α

Cardiac fibrosis is a pathological process underlying myocardial remodeling and is characterized by excessive deposition of the myocardial extracellular matrix. Long noncoding RNAs (lncRNAs) have emerged as critical regulators of various biological processes. In this study, we investigated the role of a novel lncRNA, Gm41724, in cardiac fibrosis induced by pressure overload. High-throughput whole transcriptome sequencing analysis was performed to detect differentially expressed lncRNAs in cardiac fibroblasts (CFs) with or without TGF-β1 treatment. Differential expression analysis and gene set enrichment analysis identified Gm41724 as a potential molecule targeting fibrosis. Gm41724 positively regulated the activation of CFs induced by TGF-β1 and pressure overload. Knocking down Gm41724 could inhibit the differentiation of CFs into myofibroblasts and alleviate cardiac fibrosis induced by pressure overload. Mechanistically, comprehensive identification of RNA-binding proteins by mass spectrometry (CHIRP-MS) and RNA immunoprecipitation (RIP) assay combined with other methods of molecular biological revealed the important role of Gm41724 binding to lamina-associated polypeptide 2α (lap2α) for the activation of CFs. Further mechanistic studies indicated that the regulator of G protein signaling 4 (Rgs4), as the downstream effector of Gm41724/lap2α, regulated CFs activation. Our results implicated the involvement of Gm41724 in cardiac fibrosis induced by pressure overload and it is expected to be a promising target for anti-fibrotic therapy.

Obesity-Associated ECM Remodeling in Cancer Progression

Adipose tissue, an energy storage and endocrine organ, is emerging as an essential player for ECM remodeling. Fibrosis is one of the hallmarks of obese adipose tissue, featuring excessive ECM deposition and enhanced collagen alignment. A variety of ECM components and ECM-related enzymes are produced by adipocytes and myofibroblasts in obese adipose tissue. Data from lineage-tracing models and a single-cell analysis indicate that adipocytes can transform or de-differentiate into myofibroblast/fibroblast-like cells. This de-differentiation process has been observed under normal tissue development and pathological conditions such as cutaneous fibrosis, wound healing, and cancer development. Accumulated evidence has demonstrated that adipocyte de-differentiation and myofibroblasts/fibroblasts play crucial roles in obesity-associated ECM remodeling and cancer progression. In this review, we summarize the recent progress in obesity-related ECM remodeling, the mechanism underlying adipocyte de-differentiation, and the function of obesity-associated ECM remodeling in cancer progression.

Immuno-cardio-oncology: Killing two birds with one stone?

Inflammation and a dysregulated immune system are common denominators of cancer and cardiovascular disease (CVD). Immuno-cardio-oncology addresses the interconnected immunological aspect in both cancer and CVD and the integration of immunotherapies and anti-inflammatory therapies in both distinct disease entities. Building on prominent examples of convergent inflammation (IL-1ß biology) and immune disbalance (CD20 cells) in cancer and CVD/heart failure, the review tackles both the roadblocks and opportunities of repurposed use of IL-1ß drugs and anti-CD20 antibodies in both fields, and discusses the use of advanced therapies e.g. chimeric antigen receptor (CAR) T cells, that can address the raising burden of both cancer and CVD. Finally, it is discussed how inspired by precision medicine in oncology, the use of biomarker-driven patient stratification is needed to better guide anti-inflammatory/immunomodulatory therapeutic interventions in cardiology.

Aminoacylase-1 plays a key role in myocardial fibrosis and the therapeutic effects of 20(S)-ginsenoside Rg3 in mouse heart failure

We previously found that the levels of metabolite N-acetylglutamine were significantly increased in urine samples of patients with heart failure (HF) and in coronary artery ligation (CAL)-induced HF mice, whereas the expression of its specific metabolic-degrading enzyme aminoacylase-1 (ACY1) was markedly decreased. In the current study, we investigated the role of ACY1 in the pathogenesis of HF and the therapeutic effects of 20(S)-ginsenoside Rg3 in HF experimental models in vivo and in vitro. HF was induced in mice by CAL. The mice were administered Rg3 (7.5, 15, 30 mg · kg^-1· d^-1, i.g.), or positive drug metoprolol (Met, 5.14 mg · kg^-1· d^-1, i.g.), or ACY1 inhibitor mono-tert-butyl malonate (MTBM, 5 mg · kg^-1 · d^-1, i.p.) for 14 days. We showed that administration of MTBM significantly exacerbated CAL-induced myocardial injury, aggravated cardiac dysfunction, and pathological damages, and promoted myocardial fibrosis in CAL mice. In Ang II-induced mouse cardiac fibroblasts (MCFs) model, overexpression of ACY1 suppressed the expression of COL3A1 and COL1A via inhibiting TGF-β1/Smad3 pathway, whereas ACY1-siRNA promoted the cardiac fibrosis responses. We showed that a high dose of Rg3 (30 mg · kg^-1· d^-1) significantly decreased the content of N-acetylglutamine, increased the expression of ACY1, and inhibited TGF-β1/Smad3 pathway in CAL mice; Rg3 (25 μM) exerted similar effects in Ang II-treated MCFs. Meanwhile, Rg3 treatment ameliorated cardiac function and pathological features, and it also attenuated myocardial fibrosis in vivo and in vitro. In Ang II-treated MCFs, the effects of Rg3 on collagen deposition and TGF-β1/Smad3 pathway were slightly enhanced by overexpression of ACY1, whereas ACY1 siRNA partially weakened the beneficial effects of Rg3, suggesting that Rg3 might suppress myocardial fibrosis through ACY1. Our study demonstrates that N-acetylglutamine may be a potential biomarker of HF and its specific metabolic-degrading enzyme ACY1 could be a potential therapeutic target for the prevention and treatment of myocardial fibrosis during the development of HF. Rg3 attenuates myocardial fibrosis to ameliorate HF through increasing ACY1 expression and inhibiting TGF-β1/Smad3 pathway, which provides some references for further development of anti-fibrotic drugs for HF.

The RalGAPα1-RalA signal module protects cardiac function through regulating calcium homeostasis

Sarcoplasmic/endoplasmic reticulum calcium ATPase SERCA2 mediates calcium re-uptake from the cytosol into sarcoplasmic reticulum, and its dysfunction is a hallmark of heart failure. Multiple factors have been identified to modulate SERCA2 activity, however, its regulation is still not fully understood. Here we identify a Ral-GTPase activating protein RalGAPα1 as a critical regulator of SERCA2 in cardiomyocytes through its downstream target RalA. RalGAPα1 is induced by pressure overload, and its deficiency causes cardiac dysfunction and exacerbates pressure overload-induced heart failure. Mechanistically, RalGAPα1 regulates SERCA2 through direct interaction and its target RalA. Deletion of RalGAPα1 decreases SERCA2 activity and prolongs calcium re-uptake into sarcoplasmic reticulum. GDP-bound RalA, but not GTP-bound RalA, binds to SERCA2 and activates the pump for sarcoplasmic reticulum calcium re-uptake. Overexpression of a GDP-bound RalAS28N mutant in the heart preserves cardiac function in a mouse model of heart failure. Our findings have therapeutic implications for treatment of heart failure.

Integrated Bioinformatics Identifies FREM1 as a Diagnostic Gene Signature for Heart Failure

Objective

This study is aimed at integrating bioinformatics and machine learning to determine novel diagnostic gene signals in the progression of heart failure disease.

Methods

The heart failure microarray datasets and RNA-seq datasets have been downloaded from the public database. Differentially expressed genes (DE genes) are screened out, and then, we analyze their biological functions and pathways. Integrating three machine learning methods, the least absolute shrinkage and selection operator (LASSO) algorithm, random forest (RF) algorithm, and support vector machine recursive feature elimination (SVM-RFE) are used to determine candidate diagnostic gene signals. Then, external independent RNA-seq datasets evaluate the diagnostic value of gene signals. Finally, the convolution tool CIBERSORT estimated the composition pattern of immune cell subtypes in heart failure and carried out a correlation analysis combined with gene signals.

Results

Under the set threshold, we obtained 47 DE genes with the most significant differences. Enrichment analysis shows that most of them are related to hypertrophy, matrix structural constituent, protein binding, inflammatory immune pathway, cardiovascular disease, and inflammatory disease. Three machine learning methods assisted in determining the potential characteristic signals Fras1-related extracellular matrix 1 (FREM1) and meiosis-specific nuclear structural 1 (MNS1). Validation of external datasets confirms that FREM1 is a diagnostic gene signal for heart failure. Immune cell subtypes of tissue specimens found T cell CD8, mast cell resting, T cell CD4 memory resting, T cell regulation (Tregs), monocytes, macrophages M2, T cell CD4 naive, macrophages M0, and neutrophils are associated with HF.

Conclusion

The gene signal FREM1 may be a potential molecular target in the development of HF and is related to the difference in immune infiltration of HF tissue.

Belumosudil, ROCK2-Specific Inhibitor, alleviates cardiac fibrosis by inhibiting cardiac fibroblasts activation

Cardiac fibrosis is thought to be the hallmark of pathological hypertrophic remodeling, of which the myofibroblasts transdifferentiation is the key cell biological event. However, there is still no specific and effective therapeutic agent approved for cardiac fibrosis. To investigate the effects of Belumosudil, the first ROCK2-specific inhibitor, on cardiac hypertrophy, fibrosis and dysfunction induced by pressure overload, the transverse aortic constriction (TAC) or sham operation was carried out on wild-type C57BL/6 mice (male, 6-8 week old) under pentobarbital anesthesia. After that, mice were randomly divided into three groups: sham operation + vehicle, TAC + vehicle, TAC + 50 mg·kg^-1·d^-1 Belumosudil. We found that Belumosudil effectively ameliorated cardiac hypertrophy, fibrosis and dysfunction in TAC mice. To elucidate the underlying mechanism, we inhibited the expression of ROCK2 in vitro by either Belumosudil or siRNA. We showed that the inhibition of ROCK2 by either Belumosudil or knockdown suppressed cardiac fibroblasts activation and proliferation significantly induced by Transforming Growth Factor-β1 (TGF-β1). Furthermore, our study confirmed ROCK2 mediates cardiac fibrosis by interacting with Transforming Growth Factor-β1 (TGF-β1)/mothers against decapentaplegic homolog (Smad2) pathway. Taken together, we demonstrated that Belumosudil ameliorates cardiac hypertrophy and fibrosis induced by TAC via inhibiting cardiac fibroblasts activation. In conclusion, Belumosudil may be a promising therapeutic drug for cardiac hypertrophy and fibrosis induced by myocardial pressure overload.

Preclinical platforms to study therapeutic efficacy of human γδ T cells

BACKGROUND

Gamma delta (γδ) T lymphocytes are promising candidate for adoptive T cell therapy, however, their treatment efficacy is not satisfactory. Vδ2 T cells are unique to primates and few suitable models are available to assay their anti-tumour function.

METHODS

We tested human γδ T cell activation, tumour infiltration, and tumour-killing in four three-dimensional (3D) models, including unicellular, bicellular and multicellular melanoma spheroids, and patient-derived melanoma organoids. We studied the effects of checkpoint inhibitors on γδ T cells and performed a small molecule screen using these platforms.

RESULTS

γδ T cells rapidly responded to melanoma cells and infiltrated melanoma spheroids better than αβ T cells in PBMCs. Cancer-associated fibroblasts (CAFs) in bicellular spheroids, stroma cells in multicellular melanoma spheroids and inhibitory immune cells in organoids significantly inhibited immune cell infiltrates including γδ T cells and lessened their cytotoxicity to tumour cells. Tumour-infiltrating γδ T cells showed exhausted immunophenotypes with high checkpoints expression (CTLA-4, PD-1 and PD-L1). Immune checkpoint inhibitors increased γδ T cell infiltration of 3D models and killing of melanoma cells in all four 3D models. Our small molecule screen assay and subsequent mechanistic studies demonstrated that epigenetic modifiers enhanced the chemotaxis and cytotoxicity of γδ T cells through upregulating MICA/B, inhibiting HDAC6/7 pathway and downregulating the levels of PD-L1 and PD-L2 in CAFs and tumour cells. These compounds increased CXCR4 and CD107a expression, IFN-γ production and decreased PD-1 expression of γδ T cells.

CONCLUSIONS

Tumour-infiltrating γδ T cells show exhausted immunophenotypes and limited anti-tumour capacity in melanoma 3D models. Checkpoint inhibitors and epigenetic modifiers enhance anti-tumour functions of γδ T cells. These four 3D models provided valuable preclinical platforms to test γδ T cell functions for immunotherapy.

Ongoing Clinical Trials in Aging-Related Tissue Fibrosis and New Findings Related to AhR Pathways

Fibrosis is a pathological manifestation of wound healing that replaces dead/damaged tissue with collagen-rich scar tissue to maintain homeostasis, and complications from fibrosis contribute to nearly half of all deaths in the industrialized world. Ageing is closely associated with a progressive decline in organ function, and the prevalence of tissue fibrosis dramatically increases with age. Despite the heavy clinical and economic burden of organ fibrosis as the population ages, to date, there is a paucity of therapeutic strategies that are specifically designed to slow fibrosis. Aryl hydrocarbon receptor (AhR) is an environment-sensing transcription factor that exacerbates aging phenotypes in different tissues that has been brought back into the spotlight again with economic development since AhR could interact with persistent organic pollutants derived from incomplete waste combustion. In addition, gut microbiota dysbiosis plays a pivotal role in the pathogenesis of numerous diseases, and microbiota-associated tryptophan metabolites are dedicated contributors to fibrogenesis by acting as AhR ligands. Therefore, a better understanding of the effects of tryptophan metabolites on fibrosis modulation through AhR may facilitate the exploitation of new therapeutic avenues for patients with organ fibrosis. In this review, we primarily focus on how tryptophan-derived metabolites are involved in renal fibrosis, idiopathic pulmonary fibrosis, hepatic fibrosis and cardiac fibrosis. Moreover, a series of ongoing clinical trials are highlighted.

Integrative Analysis of Bulk and Single-Cell RNA Sequencing Data Reveals Cell Types Involved in Heart Failure

Owing to the high mortality rates of heart failure (HF), a more detailed description of the HF becomes extremely urgent. Since the pathogenesis of HF remain elusive, a thorough identification of the genetic factors will provide novel insights into the molecular basis of this cardiac dysfunction. In our research, we performed publicly available transcriptome profiling datasets, including non-failure (NF), dilated cardiomyopathy (DCM) and ischemic cardiomyopathy (ICM) hearts tissues. Through principal component analysis (PCA), gene differential expression analysis, gene set enrichment analysis (GSEA), and gene Set Variation Analysis (GSVA), we figured out the candidate genes noticeably altered in HF, the specific biomarkers of endothelial cell (EC) and cardiac fibrosis, then validated the differences of the inflammation-related cell adhesion molecules (CAMs), extracellular matrix (ECM) genes, and immune responses. Taken together, our results suggested the EC and fibroblast could be activated in response to HF. DCM and ICM had both commonality and specificity in the pathogenesis of HF. Higher inflammation in ICM might related to autocrine CCL3/CCL4-CCR5 interaction induced chemokine signaling activation. Furthermore, the activities of neutrophil and macrophage were higher in ICM than DCM. These findings identified features of the landscape of previously underestimated cellular, transcriptomic heterogeneity between ICM and DCM.

High-output Cardiac Failure: A Forgotten Phenotype in Clinical Practice

INTRODUCTION

The knowledge on High-Output Cardiac Failure (HOCF) has greatly improved in the last two decades. One of the advances was the identification of a new phenotype of HOCF, characterized by the absence of ventricular dilation, already associated with liver disease, Arteriovenous Fistulas (AVF), lung disease, myelodysplastic syndromes, and obesity. However, it has been noted that any aetiology can present with one of the two phenotypes, depending on the evolution.

OBJECTIVE

The study aims to describe, through an integrative review, the physiopathology and aetiologies of HOCF and to discuss phenotypes associated with this condition.

METHODS

Revisions, guidelines, case-controls, cohort studies and clinical studies were searched in MEDLINE and LILACS, using the connectives in the "cardiac output, high" database (MeSH Terms) OR "high cardiac output" (All Fields).

DISCUSSION

Two distinct phenotypes are currently described in the HOCF, regardless of the aetiology: 1) one with enlarged cardiac chambers; and 2) with normal heart chambers. The mechanisms related to HOCF are vasodilation, arteriovenous shunts that cause increased microvascular density, Reduced Systemic Vascular Resistance (RSVR), and high metabolism. These mechanisms lead to activation of the renin-angiotensin-aldosterone system, sodium and water retention, activation of neprilysin, of the sodium-glucose-2 transporter, which promote interstitial fibrosis, ventricular remodeling and a consequent increase in cardiac output >8L/min.

CONCLUSION

Many aetiologies of HOCF have been described, and some of them are potentially curable. Prompt recognition of this condition and proper treatment may lead to better outcomes.

Deciphering the Protein, Modular Connections and Precision Medicine for Heart Failure With Preserved Ejection Fraction and Hypertension Based on TMT Quantitative Proteomics and Molecular Docking

Background: Exploring the potential biological relationships between heart failure with preserved ejection fraction (HFpEF) and concomitant diseases has been the focus of many studies for the establishment of personalized therapies. Hypertension (HTN) is the most common concomitant disease in HFpEF patients, but the functional connections between HFpEF and HTN are still not fully understood and effective treatment strategies are still lacking.

Methods: In this study, tandem mass tag (TMT) quantitative proteomics was used to identify disease-related proteins and construct disease-related networks. Furthermore, functional enrichment analysis of overlapping network modules was used to determine the functional similarities between HFpEF and HTN. Molecular docking and module analyses were combined to identify therapeutic targets for HFpEF and HTN.

Results: Seven common differentially expressed proteins (co-DEPs) and eight overlapping modules were identified in HFpEF and HTN. The common biological processes between HFpEF and HTN were mainly related to energy metabolism. Myocardial contraction, energy metabolism, apoptosis, oxidative stress, immune response, and cardiac hypertrophy were all closely associated with HFpEF and HTN. Epinephrine, sulfadimethoxine, chloroform, and prednisolone acetate were best matched with the co-DEPs by molecular docking analyses.

Conclusion: Myocardial contraction, energy metabolism, apoptosis, oxidative stress, immune response, and cardiac hypertrophy were the main functional connections between HFpEF and HTN. Epinephrine, sulfadimethoxine, chloroform, and prednisolone acetate could potentially be effective for the treatment of HTN and HFpEF.

Inhibition of Interleukin-21 prolongs the survival through the promotion of wound healing after myocardial infarction

Ly6C^low macrophages promote scar formation and prevent early infarct expansion after myocardial infarction (MI). Although CD4⁺ T cells influence the regulation of Ly6C^low macrophages after MI, the mechanism remains largely unknown. Based on the hypothesis that some molecule(s) secreted by CD4⁺ T cells act on Ly6C^low macrophages, we searched for candidate molecules by focusing on cytokine receptors expressed on Ly6C^low macrophages. Comparing the transcriptome between Ly6C^high macrophages and Ly6C^low macrophages harvested from the infarcted heart, we found that Ly6C^low macrophages highly expressed the receptor for interleukin (IL)-21, a pleiotropic cytokine which is produced by several types of CD4⁺ T cells, compared with Ly6C^high macrophages. Indeed, CD4⁺ T cells harvested from the infarcted heart produce IL-21 upon stimulation. Importantly, the survival rate and cardiac function after MI were significantly improved in IL-21-deficient (il21^-/-) mice compared with those in wild-type (WT) mice. Transcriptome analysis of infarcted heart tissue from WT mice and il21^-/- mice at 5 days after MI demonstrated that inflammation is persistent in WT mice compared with il21^-/- mice. Consistent with the transcriptome analysis, the number of neutrophils and matrix metalloproteinase (MMP)-9 expression were significantly decreased, whereas the number of Ly6C^low macrophages and MMP-12 expression were significantly increased in il21^-/- mice. In addition, collagen deposition and the number of myofibroblasts in the infarcted area were significantly increased in il21^-/- mice. Consistently, IL-21 enhanced the apoptosis of Ly6C^low macrophages. Finally, administration of neutralizing IL-21 receptor Fc protein increased the number of Ly6C^low macrophages in the infarcted heart and improved the survival and cardiac function after MI. Thus, IL-21 decreases the survival after MI, possibly through the delay of wound healing by inducing the apoptosis of Ly6C^low macrophages.

TNAP is a novel regulator of cardiac fibrosis after myocardial infarction by mediating TGF-β/Smads and ERK1/2 signaling pathways

BACKGROUND

Cardiac fibrosis is the most important pathogenesis leading to cardiac remodeling and heart failure after myocardial infarction (MI). Tissue nonspecific alkaline phosphatase (TNAP) has recently been recognized as a potential prognostic factor for MI. Nevertheless, the role of TNAP in cardiac fibrosis after MI has not been explicitly delineated.

METHODS

A systematic review and meta-analysis was conducted to assess the effect of serum TNAP levels on mortality in patients with ischemic heart disease (IHD). A correlation analysis was performed to investigate the relationship between serum levels of TNAP and biomarkers of fibrosis. Heart biopsies from patients with MI and a mouse model of MI were used to detect the expression and distribution of TNAP. Furthermore, we established adenovirus-mediated knockdown and overexpression of TNAP, using a combination of in vivo and in vitro studies in mice, to determine the role and mechanism of TNAP in cardiac fibrosis after MI. In the in vitro studies, cardiac fibroblasts were cultured on soft plates.

FINDINGS

After searching the main databases and performing a detailed assessment of the full-text articles, eight studies with 14,816 individuals were included in the quantitative analysis. We found that a high serum TNAP level was associated with an increased risk of mortality in patients with IHD and MI. The correlation analysis revealed a positive correlation between serum TNAP levels and the concentration of fibrosis biomarkers (PICP/PIIINP). The expression of TNAP was upregulated in the myocardium of patients with MI and in a mouse model of MI, accompanied by fibroblast activation and the deposition of collagen fibers. In the in vivo study, TNAP knockdown ameliorated cardiac fibrosis and improved cardiac function in mice. TNAP overexpression aggravated cardiac fibrosis and worsened cardiac function. In the in vitro study, TNAP promoted cardiac fibroblast differentiation, migration and proliferation. Mechanistically, the pro-fibrotic effect of TNAP on cardiac fibroblasts was at least partially achieved by activating the TGF-β1/Smads and ERK1/2 signaling pathways.

INTERPRETATION

Based on these findings, TNAP plays an important pro-fibrotic role in cardiac fibrosis after MI by activating TGF-β/Smads and ERK1/2 signaling, indicating that it functions as a potential regulator of and therapeutic target in cardiac fibrosis.

FUNDING

This work was supported by the National Natural Science Foundation of China.

Isolation and culture of adult murine cardiac atrial and ventricular fibroblasts and myofibroblasts

Cardiac fibroblasts play a critical role in extracellular matrix homeostasis, wound healing, and cardiac interstitial fibrosis: the latter being a pathophysiological response to a chronic increase in afterload. Using a standard protocol to isolate cardiac fibroblasts and maintain them in their quiescent phenotype in vitro will enable a better understanding of cardiac fibroblast biology and their role in the response to profibrotic stimuli. Here, we describe an enzymatic method for isolating cardiac fibroblasts. The resulting cells are maintained on either a collagen-coated hydrogel-bound polystyrene (compliant) substrate or standard polystyrene culture dishes (non-compliant) to obtain quiescent fibroblasts and activated fibroblasts (myofibroblasts), respectively. Fibroblasts maintained on a non-compliant substrate developed a myofibroblast phenotype, in which the αSMA immunoreactivity was markedly elevated and incorporated into the stress fibers. In contrast, ventricular and atrial fibroblasts retain their quiescent phenotype for up to 3 passages when maintained on a compliant substrate. Hence, the methodology described herein provides a simple and reproducible way to isolate adult murine atrial and ventricular cardiac fibroblasts from a single animal and, by selecting a substrate with the appropriate compliance, examine the mediators of fibroblast activation or inactivation.

Construction and analysis of a joint diagnosis model of random forest and artificial neural network for heart failure

Heart failure is a global health problem that affects approximately 26 million people worldwide. As conventional diagnostic techniques for heart failure have been in practice with various limitations, it is necessary to develop novel diagnostic models to supplement existing methods. With advances and improvements in gene sequencing technology in recent years, more heart failure-related genes have been identified. Using existing gene expression data in the Gene Expression Omnibus (GEO) database, we screened differentially expressed genes (DEGs) of heart failure and identified six key genes (HMOX2, SERPINA3, LCN6, CSDC2, FREM1, and ZMAT1) by random forest classifier. Of these genes, CSDC2, FREM1, and ZMAT1 have never been associated with heart failure. We also successfully constructed a new diagnostic model of heart failure using an artificial neural network and verified its diagnostic efficacy in public datasets.

Diverse origins and activation of fibroblasts in cardiac fibrosis

Cardiac fibroblasts (cFBs) have emerged as a heterogenous cell population. Fibroblasts are considered the main cell source for synthesis of the extracellular matrix (ECM) and as such a dysregulation in cFB function, activity, or viability can lead to disrupted ECM structure or fibrosis. Fibrosis can be initiated in response to different injuries and stimuli, and can be reparative (beneficial) or reactive (damaging). FBs need to be activated to myofibroblasts (MyoFBs) which have augmented capacity in synthesizing ECM proteins, causing fibrosis. In addition to the resident FBs in the myocardium, a number of other cells (pericytes, fibrocytes, mesenchymal, and hematopoietic cells) can transform into MyoFBs, further driving the fibrotic response. Multiple molecules including hormones, cytokines, and growth factors stimulate this process leading to generation of activated MyoFBs. Contribution of different cell types to cFBs and MyoFBs can result in an exponential increase in the number of MyoFBs and an accelerated pro-fibrotic response. Given the diversity of the cell sources, and the array of interconnected signalling pathways that lead to formation of MyoFBs and subsequently fibrosis, identifying a single target to limit the fibrotic response in the myocardium has been challenging. This review article will delineate the importance and relevance of fibroblast heterogeneity in mediating fibrosis in different models of heart failure and will highlight important signalling pathways implicated in myofibroblast activation.

Common mechanistic pathways in cancer and heart failure. A scientific roadmap on behalf of the Translational Research Committee of the Heart Failure Association (HFA) of the European Society of Cardiology (ESC)

The co-occurrence of cancer and heart failure (HF) represents a significant clinical drawback as each disease interferes with the treatment of the other. In addition to shared risk factors, a growing body of experimental and clinical evidence reveals numerous commonalities in the biology underlying both pathologies. Inflammation emerges as a common hallmark for both diseases as it contributes to the initiation and progression of both HF and cancer. Under stress, malignant and cardiac cells change their metabolic preferences to survive, which makes these metabolic derangements a great basis to develop intersection strategies and therapies to combat both diseases. Furthermore, genetic predisposition and clonal haematopoiesis are common drivers for both conditions and they hold great clinical relevance in the context of personalized medicine. Additionally, altered angiogenesis is a common hallmark for failing hearts and tumours and represents a promising substrate to target in both diseases. Cardiac cells and malignant cells interact with their surrounding environment called stroma. This interaction mediates the progression of the two pathologies and understanding the structure and function of each stromal component may pave the way for innovative therapeutic strategies and improved outcomes in patients. The interdisciplinary collaboration between cardiologists and oncologists is essential to establish unified guidelines. To this aim, pre-clinical models that mimic the human situation, where both pathologies coexist, are needed to understand all the aspects of the bidirectional relationship between cancer and HF. Finally, adequately powered clinical studies, including patients from all ages, and men and women, with proper adjudication of both cancer and cardiovascular endpoints, are essential to accurately study these two pathologies at the same time.

Diagnostic value of circulating microRNA-19b in heart failure

OBJECTIVE

For differentiating heart failure (HF) with preserved ejection fraction (HFpEF) from HF with reduced EF (HFrEF), N-terminal prohormone brain natriuretic peptide (NT-proBNP) is less accurate. Decreased expression of microRNA-19b (miR-19b) is associated with increased cardiac-fibrosis. We aim to evaluate the value of miR-19b in diagnosing HFrEF patients.

METHOD

We included 200 HF patients and 100 healthy controls. Intergroup comparisons of miR-19b were made and correlation between miR-19b and NT-proBNP was analysed. Diagnostic values of NT-proBNP and miR-19b for HF patients versus controls and HFrEF versus HFpEF were obtained by ROC analysis and described by area under curve (AUC), sensitivity and specificity.

RESULTS

HFrEF patients (0.87, 95% CI 0.37-1.45) had significantly lower miR-19b level than HFpEF group (1.32, 95% CI 0.63-2.51) and the controls (1.82, 95% CI 0.37-1.45) (both P < .001). There was a remarkable negative correlation between miR-19b and NT-proBNP (P < .001). The additional use of miR-19b did not improve the accuracy of NT-proBNP alone in diagnosing HF patients from the controls (both AUC = 0.98, 95%CI 0.97-0.99). However, as for distinguishing the HFpEF from HFrEF, miR-19b and NT-proBNP yielded a significantly higher AUC than NT-proBNP alone (0.85, 95% CI 0.80-0.90 vs. 0.66, 95% CI 0.58-0.74) (P < .001), and the sensitivity for diagnosing HFrEF was raised from 58% to 77% and the specificity from 75% to 79%.

CONCLUSIONS

On top of NT-proBNP, miR-19b added the value in diagnosing HFrEF. But in view of satisfactory accuracy of NT-proBNP in predicting HF from the healthy volunteers, miR-19b did not provide incremental value.

Fibroblasts: The arbiters of extracellular matrix remodeling

Extracellular matrix (ECM) is the foundation on which all cells and organs converge to orchestrate normal physiological functions. In the setting of pathology, the ECM is modified to incorporate additional roles, with modifications including turnover of existing ECM and deposition of new ECM. The fibroblast is center stage in coordinating both normal tissue homeostasis and response to disease. Understanding how fibroblasts work under normal conditions and are activated in response to injury or stress will provide mechanistic insight that triggers discovery of new therapeutic treatments for a wide range of disease. We highlight here fibroblast roles in the cancer, lung, and heart as example systems where fibroblasts are major contributors to homeostasis and pathology.

Genetics and Signaling Pathways of Laminitis

Laminitis is a devastating disease with diverse etiologies and few, if any, effective treatments. Gene expression and hypothesis-generating genomic studies have provided a fresh look at the key molecular players at crucial timepoints in diverse experimental and naturally affected tissues. We summarize findings to date, and propose a unifying model of the laminitis disease process that includes several pathogenesis concepts shared with other diseases of epidermal and epithelial tissues. The value of these new pathways as potential therapeutic targets is exciting but will require careful future work to validate new methods and launch systematic clinical trials.

Early Cardiac Remodeling Promotes Tumor Growth and Metastasis

BACKGROUND

Recent evidence suggests that cancer and cardiovascular diseases are associated. Chemotherapy drugs are known to result in cardiotoxicity, and studies have shown that heart failure and stress correlate with poor cancer prognosis. However, whether cardiac remodeling in the absence of heart failure is sufficient to promote cancer is unknown.

METHODS

To investigate the effect of early cardiac remodeling on tumor growth and metastasis colonization, we used transverse aortic constriction (TAC), a model for pressure overload-induced cardiac hypertrophy, and followed it by cancer cell implantation.

RESULTS

TAC-operated mice developed larger primary tumors with a higher proliferation rate and displayed more metastatic lesions compared with controls. Serum derived from TAC-operated mice potentiated cancer cell proliferation in vitro, suggesting the existence of secreted tumor-promoting factors. Using RNA-sequencing data, we identified elevated mRNA levels of periostin in the hearts of TAC-operated mice. Periostin levels were also found to be high in the serum after TAC. Depletion of periostin from the serum abrogated the proliferation of cancer cells; conversely, the addition of periostin enhanced cancer cell proliferation in vitro. This is the first study to show that early cardiac remodeling nurtures tumor growth and metastasis and therefore promotes cancer progression.

CONCLUSIONS

Our study highlights the importance of early diagnosis and treatment of cardiac remodeling because it may attenuate cancer progression and improve cancer outcome.

Serum and Echocardiographic Markers May Synergistically Predict Adverse Cardiac Remodeling after ST-Segment Elevation Myocardial Infarction in Patients with Preserved Ejection Fraction

Improvement of risk scoring is particularly important for patients with preserved left ventricular ejection fraction (LVEF) who generally lack efficient monitoring of progressing heart failure. Here, we evaluated whether the combination of serum biomarkers and echocardiographic parameters may be useful to predict the remodeling-related outcomes in patients with ST-segment elevation myocardial infarction (STEMI) and preserved LVEF (HFpEF) as compared to those with reduced LVEF (HFrEF). Echocardiographic assessment and measurement of the serum levels of NT-proBNP, sST2, galectin-3, matrix metalloproteinases, and their inhibitors (MMP-1, MMP-2, MMP-3, TIMP-1) was performed at the time of admission (1st day) and on the 10th–12th day upon STEMI onset. We found a reduction in NT-proBNP, sST2, galectin-3, and TIMP-1 in both patient categories from hospital admission to the discharge, as well as numerous correlations between the indicated biomarkers and echocardiographic parameters, testifying to the ongoing ventricular remodeling. In patients with HFpEF, NT-proBNP, sST2, galectin-3, and MMP-3 correlated with the parameters reflecting the diastolic dysfunction, while in patients with HFrEF, these markers were mainly associated with LVEF and left ventricular end-systolic volume/diameter. Therefore, the combination of the mentioned serum biomarkers and echocardiographic parameters might be useful for the prediction of adverse cardiac remodeling in patients with HFpEF.

Alteration of calcium signalling in cardiomyocyte induced by simulated microgravity and hypergravity

Objectives

Cardiac Ca²⁺ signalling plays an essential role in regulating excitation‐contraction coupling and cardiac remodelling. However, the response of cardiomyocytes to simulated microgravity and hypergravity and the effects on Ca²⁺ signalling remain unknown. Here, we elucidate the mechanisms underlying the proliferation and remodelling of HL‐1 cardiomyocytes subjected to rotation‐simulated microgravity and 4G hypergravity.

Materials and Methods

The cardiomyocyte cell line HL‐1 was used in this study. A clinostat and centrifuge were used to study the effects of microgravity and hypergravity, respectively, on cells. Calcium signalling was detected with laser scanning confocal microscopy. Protein and mRNA levels were detected by Western blotting and real‐time PCR, respectively. Wheat germ agglutinin (WGA) staining was used to analyse cell size.

Results

Our data showed that spontaneous calcium oscillations and cytosolic calcium concentration are both increased in HL‐1 cells after simulated microgravity and 4G hypergravity. Increased cytosolic calcium leads to activation of calmodulin‐dependent protein kinase II/histone deacetylase 4 (CaMKII/HDAC4) signalling and upregulation of the foetal genes ANP and BNP, indicating cardiac remodelling. WGA staining indicated that cell size was decreased following rotation‐simulated microgravity and increased following 4G hypergravity. Moreover, HL‐1 cell proliferation was increased significantly under hypergravity but not rotation‐simulated microgravity.

Conclusions

Our study demonstrates for the first time that Ca²⁺/CaMKII/HDAC4 signalling plays a pivotal role in myocardial remodelling under rotation‐simulated microgravity and hypergravity.