Role of Cardiac Macrophages on Cardiac Inflammation, Fibrosis and Tissue Repair

Klotho alleviates sepsis-associated myocardial inflammation and apoptosis

Klotho (KL) protects against various pathological phenotypes. The present study was designed to investigate the effect of KL on sepsis-associated cardiac dysfunction, and whether KL modulated sepsis-associated cardiac dysfunction via oxidative stress and apoptosis. Experiments were carried out in mice treated with lipopolysaccharide (LPS) to induce the septic model. The expression of KL was reduced in the heart of septic mice induced by LPS administration. The cardiac dysfunction of septic mice was deteriorated after KL KO, and was alleviated by KL upregulation. The inflammatory factors of tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β) and IL-6 were increased in the heart after LPS treatment, and these increases were further enhanced in KL deficiency mice, and were alleviated in KL overexpressed mice. The apoptosis biomarkers of B-cell lymphoma 2 (Bcl2) and Bcl2-associated X protein (Bax) levels were changed in the heart of septic mice, which were exacerbated by KL KO and were ameliorated by KL overexpression. These results indicated that KL involved in the regulation of sepsis-induced cardiac dysfunction via alleviating inflammation and apoptosis. Upregulation KL may be a therapeutic strategy to improve cardiac function in septic patients in the future.

Microcystin-LR and its health impacts: Chemistry, transmission routes, mechanisms of toxicity and target organs

Microcystin-LR, a hepatotoxin produced by cyanobacteria, poses significant health risks to humans and other animals through various routes of exposure. This review comprehensively explores the chemistry, transmission pathways, mechanisms of toxicity, and target organs affected by MC-LR to provide a detailed understanding of its health impacts on animals and humans. MC-LR exposure occurs through different transmission routes, including ingesting contaminated water and food, algal dietary supplements, direct body contact with harmful algal blooms, and inhalation of aerosolized toxins. In this review, we explored that the toxic effects of MC-LR are mediated through multiple complex mechanisms. A key mechanism of its toxicity is the inhibition of protein phosphatases PP1 and PP2A which results in abnormal cellular signalling pathways. Additionally, MC-LR induces oxidative stress and disrupts cellular homeostasis. The findings suggest that MC-LR modulates the activity of various antioxidant enzymes and also activates apoptosis pathways by different mechanisms. It also induces cytoskeletal disruption, ultimately compromising cellular integrity and function. MC-LR also induces activation of oncogenes such as Gankyrin, PI3K/AKT, HIF-1α, RAC1/JNK and NEK2 pathway and upregulates the inflammatory molecules such as NF-κβ, and TNF-α, hence leading to carcinogenesis. MC-LR has toxicological effects on multiple organs. The liver is the primary target, where MC-LR accumulates and causes hepatotoxicity, but other organs are affected as well. MC-LR shows neurotoxicity, nephrotoxicity, cardiotoxicity and reproductive toxicity.

Cardiac macrophage: Insights from murine models to translational potential for human studies

Macrophages are a cell type that are known to play dynamic roles in acute and progressive pathology. They are highly attuned to their microenvironments throughout maturation, tailoring their functional responses according to the specific tissues in which they reside and their developmental origin. Cardiac macrophages (cMacs) have emerged as focal points of interest for their interactions with the unique electrical and mechanical stimuli of the heart, as well as for their role in maintaining cardiac homeostasis. Through an in-depth analysis of their origin, lineage, and functional significance, this review aims to shed light on cMacs' distinct contributions to both normal physiological maintenance as well as disease progression. Central to our discussion is the comparison of cMac characteristics between mouse and human models, highlighting current challenges and proposing novel experimental tools for deciphering cMac function within the intricate human cardiac microenvironments based on current murine studies. Our review offers valuable insights for identifying novel therapeutic targets and interventions tailored to the distinct roles of these immune cells in cardiovascular diseases (CVDs).

Loss of macrophage fibroblast growth factor 12 attenuates cardiac fibrosis in pressure-overloaded myocardium

BACKGROUND

Cardiac fibrosis, a leading cause of death worldwide, plays a functional role in the development of heart failure. Unfortunately, there are currently no therapeutic strategies in clinical practice that can specifically attenuate the activation of cardiac fibroblasts, the effector cells of fibrosis in the heart. In this study, we aimed to identify a novel approach to target myocardial fibrosis through the crosstalk between macrophages and fibroblasts.

METHODS

We investigated the expression of fibroblast growth factor 12 (FGF12), a novel regulator of macrophage activation, in both human subjects and mouse models. We also generated myeloid cell-specific FGF12 knockout mice to determine the role of FGF12 in cardiac fibrosis. For in vitro studies, we isolated mouse primary bone marrow-derived macrophages (BMDMs) and cardiac fibroblasts to explore the mechanism by which FGF12 controls macrophage polarization and fibroblast activation.

RESULTS

We found that FGF12 expression was significantly upregulated in both human failing hearts and mouse pressure-overloaded myocardium. RNA sequencing revealed that FGF12 upregulation was associated with fibrosis progression, oxidative stress response, and macrophage activation in mouse heart tissues. Myeloid-specific knockout of FGF12 markedly attenuated pressure overload-induced myocardial fibrosis in our mouse models. We observed that FGF12 significantly affects interleukin-4-stimulated M2 polarization in BMDMs. Conditioned medium from FGF12 knockdown or overexpressed BMDMs also influenced cardiac fibroblast activation, primarily by affecting reactive oxygen species (ROS) accumulation in cardiac fibroblasts. Furthermore, we demonstrated that FGF12 controls BMDM M2 polarization through the SOCS/STAT pathway.

CONCLUSIONS

FGF12 is a novel regulator of myocardial fibrosis, acting through the modulation of crosstalk between macrophages and fibroblasts. Therapeutic approaches targeting FGF12 may represent a potential strategy to ameliorate cardiac fibrosis or other fibrosis-related diseases in the future.

The Evolving Role of Macrophage Metabolic Reprogramming in Obesity

Recent research has extensively explored the critical role of energy metabolism in shaping the inflammatory response and polarization of macrophages in obesity. This rapidly growing field emphasizes the need to understand the connection between metabolic processes that support macrophage polarization in obesity. While most published research in this area has focused on glucose and fatty acids, how the flux through other metabolic pathways (such as ketone and amino acid oxidation) in macrophages is altered in obesity is not well defined. This review summarizes the main alterations in uptake, storage, and oxidation of oxidative substrates (glucose, fatty acids, ketone bodies and amino acids) in macrophages and how these alterations are linked to macrophage polarization and contribution to augmented inflammatory markers in obesity. The review also discusses how oxidative substrates could modulate macrophage energy metabolism and inflammatory responses via feeding into other non-oxidative pathways (such as the pentose phosphate pathway, triacylglycerol synthesis/accumulation), via acting as signalling molecules, or via mediating post-translational modifications (such as O-GlcNAcylation or β-hydroxybutyrylation). The review also identifies several critical unanswered questions regarding the characteristics (functional and metabolic) of macrophages from different origins (adipose tissue, skeletal muscle, bone marrow) in obesity and how these characteristics contribute to early vs late phases of obesity. We also identified a number of new therapeutic targets that could be evaluated in future investigations. Targeting macrophage metabolism in obesity is an exciting and active area of research with significant potential to help identify new treatments to limit the detrimental effects of inflammation in obesity.

Macrophages of the Heart: Homeostasis and Disease

Cardiac macrophages (CMs) are the most abundant immune cell type in the heart. They are critical for maintaining cardiac homeostasis and in the orchestration of immune responses to ischemic and non-ischemic cardiomyopathies. Their functions are highly heterogeneous and regulated by their tissue microenvironment. CMs have high plasticity, which allows them to perform various functions in the myocardium to bring about homeostasis within the cardiovascular system (CVS). CMs also play critical roles in coronary development and angiogenesis, tissue repair and remodeling, cardiac conduction and in the clearance of necrotic and apoptotic cells. However, there is a paucity of studies on the biology of cardiac macrophages in both steady state and disease, especially, in humans. In this review, we discuss the multifaceted roles of CMs in the heart, focusing on their ontogeny, homeostatic functions and immunological responses during inflammation and reparative processes post-injury. We highlight the heterogeneity of CMs in their ontogeny, phenotypes and functions as well as their roles in the pathogenesis of pathological conditions such as myocarditis, myocardial fibrosis and heart failure. Understanding the unique characteristics of cardiac macrophages in the cardiac milieu is critical for the development of macrophage-specific therapeutic interventions to alleviate the global burden of cardiovascular disease (CVD). Therefore, future studies should focus on further improving the understanding of the biology of cardiac macrophages to harness their potential as therapeutic targets for cardiovascular disorders.

Cardiomyocyte-derived Galectin-9 induces macrophage M2 polarization via the TIM3 pathway to attenuate myocardial remodeling post-myocardial infarction

M2 macrophages play a key role in tissue repair during the late stages of myocardial infarction (MI). This study highlights the influence of cardiomyocyte-derived Galectin-9 on macrophage function post-MI. Using a murine model with left anterior descending (LAD) artery ligation, we examined the effects of Galectin-9 deficiency, exogenous Galectin-9 supplementation, and macrophage depletion on myocardial macrophage polarization and tissue remodeling. Our results showed increased Galectin-9 expression in infarcted myocardial tissue. Galectin-9 deficiency impaired cardiac recovery and reduced M2 macrophage presence in the infarcted area. Supplementation with exogenous Galectin-9 improved tissue remodeling in Galectin-9-deficient mice and increased M2 macrophage levels. However, macrophage depletion negated the benefits of Galectin-9 supplementation, exacerbating cardiac dysfunction. In vitro, Galectin-9 enhanced the M2 phenotype in macrophage-like RAW264.7 cells after hypoxic preconditioning of cardiomyocytes. This effect was diminished when cardiomyocytes lacked Galectin-9. TIM3 knockdown in RAW264.7 cells reversed the M2 polarization induced by recombinant Galectin-9 and inhibited the PI3K/Akt signaling pathway. These findings suggest that injured cardiomyocytes release Galectin-9 after MI, which binds to TIM3 on macrophages, activating the PI3K/Akt pathway to promote M2 polarization. This cardiomyocyte-macrophage interaction mitigates myocardial remodeling and helps preserve cardiac function after MI.

IGF2BP2: an m6A reader that affects cellular function and disease progression

Insulin-like growth factor 2 messenger RNA (mRNA)-binding protein 2 (IGF2BP2) is a widely studied N6-methyladenosine (m6A) modification reader, primarily functioning to recognize and bind to m6A modification sites on the mRNA of downstream target genes, thereby enhancing their stability. Previous studies have suggested that the IGF2BP2-m6A modification plays an essential role in cellular functions and the progression of various diseases. In this review, we focus on summarizing the molecular mechanisms by which IGF2BP2 enhances the mRNA stability of downstream target genes through m6A modification, thereby regulating cell ferroptosis, epithelial-mesenchymal transition (EMT), stemness, angiogenesis, inflammatory responses, and lipid metabolism, ultimately affecting disease progression. Additionally, we update the related research progress on IGF2BP2. This article aims to elucidate the effects of IGF2BP2 on cell ferroptosis, EMT, stemness, angiogenesis, inflammatory responses, and lipid metabolism, providing a new perspective for a comprehensive understanding of the relationship between IGF2BP2 and cell functions such as ferroptosis and EMT, as well as the potential for targeted IGF2BP2 therapy for tumors and other diseases.

The immunology of diabetic cardiomyopathy

Diabetic cardiomyopathy is a notable microvascular complication of diabetes, characterized primarily by myocardial fibrosis and functional abnormalities. Long-term hyperglycemia induces excessive activation and recruitment of immune cells and triggers the cascade of inflammatory responses, resulting in systemic and local cardiac inflammation. Emerging evidence highlights the significant roles of immunology in modulating the pathology of diabetic cardiomyopathy. As the primary effectors of inflammatory reactions, immune cells are consistently present in cardiac tissue and can be recruited under pathological hyperglycemia circumstances. A disproportionate favor to proinflammatory types of immune cells and the increased proinflammatory cytokine levels mediate fibroblast proliferation, phenotypic transformation, and collagen synthesis and ultimately rise to cardiac fibrosis and hypertrophy. Meanwhile, the severity of cardiac fibrosis is also strongly associated with the diverse phenotypes and phenotypic alterations of the immune cells, including macrophages, dendritic cells, mast cells, neutrophils, and natural killer cells in innate immunity and CD4+ T lymphocytes, CD8+ T lymphocytes, and B lymphocytes in adaptive immunity. In this review, we synthesized the current analysis of the critical role played by the immune system and its components in the progression of diabetic cardiomyopathy. Finally, we highlight preclinical and clinical immune targeting strategies and translational implications.

Autophagy and Its Association with Macrophages in Clonal Hematopoiesis Leading to Atherosclerosis

Atherosclerosis, a chronic inflammatory disease characterized by lipid accumulation and immune cell infiltration, is linked to plaque formation and cardiovascular events. While traditionally associated with lipid metabolism and endothelial dysfunction, recent research highlights the roles of autophagy and clonal hematopoiesis (CH) in its pathogenesis. Autophagy, a cellular process crucial for degrading damaged components, regulates macrophage homeostasis and inflammation, both of which are pivotal in atherosclerosis. In macrophages, autophagy influences lipid metabolism, cytokine regulation, and oxidative stress, helping to prevent plaque instability. Defective autophagy exacerbates inflammation, impairs cholesterol efflux, and accelerates disease progression. Additionally, autophagic processes in endothelial cells and smooth muscle cells further contribute to atherosclerotic pathology. Recent studies also emphasize the interplay between autophagy and CH, wherein somatic mutations in genes like TET2, JAK2, and DNMT3A drive immune cell expansion and enhance inflammatory responses in atherosclerotic plaques. These mutations modify macrophage function, intensifying the inflammatory environment and accelerating atherosclerosis. Chaperone-mediated autophagy (CMA), a selective form of autophagy, also plays a critical role in regulating macrophage inflammation by degrading pro-inflammatory cytokines and oxidized low-density lipoprotein (ox-LDL). Impaired CMA activity leads to the accumulation of these substrates, activating the NLRP3 inflammasome and worsening inflammation. Preclinical studies suggest that pharmacologically activating CMA may mitigate atherosclerosis progression. In animal models, reduced CMA activity accelerates plaque instability and increases inflammation. This review highlights the importance of autophagic regulation in macrophages, focusing on its role in inflammation, plaque formation, and the contributions of CH. Building upon current advances, we propose a hypothesis in which autophagy, programmed cell death, and clonal hematopoiesis form a critical intrinsic axis that modulates the fundamental functions of macrophages, playing a complex role in the development of atherosclerosis. Understanding these mechanisms offers potential therapeutic strategies targeting autophagy and inflammation to reduce the burden of atherosclerotic cardiovascular disease.

Claudin 1 dysregulation disrupts coronary microvascular integrity and impairs cardiac function

BACKGROUND AND AIMS

Claudin 1 (Cldn1) is a tight junction protein primarily known for its role in epithelial and endothelial barrier function. However, the role of Cldn1 in coronary microvascular barrier remain unclear. The aim of this study is to investigate the biological effects of Cldn1 dysregulation on coronary vascular permeability, inflammation, fibrosis, and left ventricular function.

METHODS

Cldn1 was silenced in human cardiac microvascular endothelial cells (HMVECs) and C57Bl/6 mice using oligonucleotide-based next generation siRNA duplex. Additionally, global transgenic mice with endothelial cell-specific overexpression of Cldn1 were created under the regulation of the CD144 (VE-cadherin) promoter. Permeability was assessed using FITC-dextran assay in vitro and Evans blue dye leakage (Mile's assay) in vivo. Cardiac morphology and function were measured by cardiac MRI, and myocardial pathology was analyzed by immunohistochemistry and Transmission Electron Microscopy (TEM). PCR and Western blotting confirmed Cldn1 expression changes.

RESULTS

Cldn1 knockdown reduced protein levels by 46% (p = 0.004) and significantly increased endothelial permeability in HMVEC (p = 0.0007). In mice, Cldn1 knockdown significantly increased Evans blue dye leakage (p = 0.025), macrophage infiltration (p = 0.018), and interstitial collagen (p = 0.048). TEM confirmed endothelial damage particularly affecting the basement membrane structure. Cardiac MRI showed reduced stroke volume (p = 0.004) and ejection fraction (p = 0.043). Cldn1 overexpression reduced vascular permeability (p = 0.002) without altering cardiac function under basal condition.

CONCLUSION

Cldn1 plays an important role in maintaining coronary microvascular barrier integrity. Its loss leads to increased permeability, inflammation, fibrosis, and impaired cardiac function, while overexpression enhances barrier function without affecting cardiac performance under baseline conditions.

Baicalin and baicalein against myocardial ischemia-reperfusion injury: A review of the current documents

Myocardial ischemia-reperfusion injury (MIRI) is a significant challenge in the treatment of ischemic heart disease (IHD), arising as a complication from reperfusion therapies designed to restore blood flow after an ischemic event. Despite the availability of various therapeutic strategies, finding an effective treatment for MIRI remains difficult. Baicalin and its aglycone form (baicalein), natural compounds derived from the Chinese skullcap plant (Scutellaria baicalensis), have shown promise due to their antioxidant, anti-inflammatory, and cardioprotective properties. This review aims to explore the potential of baicalin and baicalein as treatments for MIRI, with a focus on their molecular and cellular level effects. These natural agents can decrease oxidative stress by promoting antioxidant enzymes and decreasing harmful oxidative substances that damage cardiac cells. They also exert anti-inflammatory effects by blocking specific pathways that trigger the release of inflammatory mediators. Additionally, they also improve heart cell survival, infarct region, and overall cardiac function by inhibiting key signaling pathways involved in cell death. Research in both animal and cell models suggests that these flavonoids, especially baicalin, can restore cardiac health following MIRI, improving cardiac performance, and reducing cardiac damage. These findings underscore the potential of baicalin and baicalein as therapeutic options for MIRI. However, further research and clinical trials are necessary to elucidate their mechanisms fully and to develop baicalin into a viable treatment.

Relevance of Targeting Oxidative Stress, Inflammatory, and Pro-Resolution Mechanisms in the Prevention and Management of Postoperative Atrial Fibrillation

Atrial fibrillation (AF) is the most common cardiac arrhythmia. AF can lead to severe complications, including stroke, myocardial infarction, and sudden death. AF risk factors include pathological aging and conditions such as obesity, diabetes, and hypertension. Clinical data revealed that cardiothoracic and non-cardiothoracic surgeries are also important risk factors for AF. Post-operative AF (POAF) is associated with important public health costs caused by increased hospitalization, frequent emergency room visits, and enhanced healthcare utilization, which altogether lead to a low quality of life for the patients. Hence, POAF is a major clinical challenge, and there is an urgent need for the development of novel therapeutic strategies. Interestingly, evidence from clinical and fundamental research converges to identify cardiac oxidative stress and atrial inflammation as the common denominators of all AF risk factors. Unresolved inflammation is suspected to provoke cardiac fibrosis, which is an important contributor to cardiac arrhythmias and AF. Antioxidant, anti-inflammatory, and pro-resolution strategies may help to combat post-operative cardiac remodeling and POAF. This article aims to review the current scientific evidence supporting the role of inflammation in the pathogenesis of POAF and explore potential novel therapeutic strategies to prevent and mitigate inflammation in the management of AF.

Extracellular matrix in cardiac morphogenesis, fibrosis, and regeneration

The extracellular matrix (ECM) plays a crucial role in providing structural integrity and regulating cell communication essential for organ development, homeostasis, and regeneration, including hearts. Evidence indicates that disruptions in the spatiotemporal expression or alterations in ECM components lead to cardiac malformations, including a wide range of congenital heart diseases (CHDs). Furthermore, research on injured hearts across various vertebrate species, some of which show effective regeneration while others experience irreversible fibrosis, underscores the significance of ECM molecules in cardiac regeneration. This review presents an overview of heart development and the dynamics of ECM during cardiac morphogenesis, beginning with the formation of the contractile heart tube and advancing to the development of distinct chambers separated by valves to facilitate unidirectional blood flow. Furthermore, we discuss research emphasizing the multifaceted roles of secreted molecules in mediating fibrosis and regeneration following myocardial injury.

Tissue macrophages: origin, heterogenity, biological functions, diseases and therapeutic targets

Macrophages are immune cells belonging to the mononuclear phagocyte system. They play crucial roles in immune defense, surveillance, and homeostasis. This review systematically discusses the types of hematopoietic progenitors that give rise to macrophages, including primitive hematopoietic progenitors, erythro-myeloid progenitors, and hematopoietic stem cells. These progenitors have distinct genetic backgrounds and developmental processes. Accordingly, macrophages exhibit complex and diverse functions in the body, including phagocytosis and clearance of cellular debris, antigen presentation, and immune response, regulation of inflammation and cytokine production, tissue remodeling and repair, and multi-level regulatory signaling pathways/crosstalk involved in homeostasis and physiology. Besides, tumor-associated macrophages are a key component of the TME, exhibiting both anti-tumor and pro-tumor properties. Furthermore, the functional status of macrophages is closely linked to the development of various diseases, including cancer, autoimmune disorders, cardiovascular disease, neurodegenerative diseases, metabolic conditions, and trauma. Targeting macrophages has emerged as a promising therapeutic strategy in these contexts. Clinical trials of macrophage-based targeted drugs, macrophage-based immunotherapies, and nanoparticle-based therapy were comprehensively summarized. Potential challenges and future directions in targeting macrophages have also been discussed. Overall, our review highlights the significance of this versatile immune cell in human health and disease, which is expected to inform future research and clinical practice.

Research Advances in Myocardial Infarction Repair and Cardiac Regenerative Medicine via the Notch Signaling Pathway

Acute myocardial infarction is myocardial necrosis caused by acute and persistent ischemia and hypoxia in the coronary artery and severely affects public health. Recently, stem cell research has presented transformational developments in treating myocardial infarction. The Notch signaling pathway plays a crucial role in the post-myocardial infarction repair process and cardiac regenerative medicine. Additionally, the Notch signaling pathway can be involved in regulating the inflammatory response, myocardial fibrosis, oxidative stress, cardiomyocyte apoptosis, and cardiomyocyte regeneration after myocardial infarction. Moreover, the Notch signaling pathway is applied in cardiac tissue engineering. This review mainly elaborates on the research on the Notch signaling pathway in repairing myocardial infarction and cardiac regenerative medicine, aiming to provide a reference for treating acute myocardial infarction.

Macrophage energy metabolism in cardiometabolic disease

In a rapidly expanding body of literature, the major role of energy metabolism in determining the response and polarization status of macrophages has been examined, and it is currently a very active area of research. The metabolic flux through different metabolic pathways in the macrophage is interconnected and complex and could influence the polarization of macrophages. Earlier studies suggested glucose flux through cytosolic glycolysis is a prerequisite to trigger the pro-inflammatory phenotypes of macrophages while proposing that fatty acid oxidation is essential to support anti-inflammatory responses by macrophages. However, recent studies have shown that this understanding is oversimplified and that the metabolic control of macrophage polarization is highly complex and not fully defined yet. In this review, we systematically reviewed and summarized the literature regarding the role of energy metabolism in controlling macrophage activity and how that might be altered in cardiometabolic diseases, namely heart failure, obesity, and diabetes. We critically appraised the experimental studies and methodologies in the published studies. We also highlighted the challenging concepts in macrophage metabolism and identified several research questions yet to be addressed in future investigations.

The various roles of TREM2 in cardiovascular disease

Triggering receptor expressed on myeloid cells-2 (TREM2) is a transmembrane immune receptor that is expressed mainly on macrophages. As a pathology-induced immune signaling hub, TREM2 senses tissue damage and activates immune remodeling in response. Previous studies have predominantly focused on the TREM2 signaling pathway in Alzheimer's disease, metabolic syndrome, and cancer. Recent research has indicated that TREM2 signaling is also activated in various cardiovascular diseases. In this review, we summarize the current understanding and the unanswered questions regarding the role of TREM2 signaling in mediating the metabolism and function of macrophages in atherosclerosis and various models of heart failure. In the context of atherosclerosis, TREM2 signaling promotes foam cell formation and is crucial for maintaining macrophage survival and plaque stability through efferocytosis and cholesterol efflux. Recent studies on myocardial infarction, sepsis-induced cardiomyopathy, and hypertensive heart failure also implicated the protective role of TREM2 signaling in cardiac macrophages through efferocytosis and paracrine functions. Additionally, we discuss the clinical significance of elevated soluble TREM2 (sTREM2) in cardiovascular disease and propose potential therapies targeting TREM2. The overall aim of this review is to highlight the various roles of TREM2 in cardiovascular diseases and to provide a framework for therapeutic strategies targeting TREM2.

Bioinformatics analysis of the expression of potential common genes and immune-related genes between atrial fibrillation and chronic kidney disease

Research objective

This study is based on bioinformatics analysis to explore the co-expressed differentially expressed genes (DEGs) between atrial fibrillation (AF) and chronic kidney disease (CKD), identify the biomarkers for the occurrence and development of the two diseases, investigate the potential connections between AF and CKD, and explore the associations with immune cells.

Methods

We downloaded Two AF gene chip datasets (GSE79768, GSE14975) and two CKD gene chip datasets (GSE37171, GSE120683) from the GEO database. After pre-processing and standardizing the datasets, two DEGs datasets were obtained. The DEGs were screened using R language, and the intersection was taken through Venn diagrams to obtain the co-expressed DEGs of AF and CKD. To obtain the signal pathways where the co-expressed DEGs were significantly enriched, GO/KEGG enrichment analyses were used to analysis the co-expressed DEGs. The Cytoscape software was used to further construct a PPI network and screen key characteristic genes, and the top 15 co-expressed DEGs were screened through the topological algorithm MCC. To further screen key characteristic genes, two machine-learning algorithms, LASSO regression and RF algorithm, were performed to screen key characteristic genes for the two disease datasets respectively to determine the diagnostic values of the characteristic genes in the two diseases. The GeneMANIA online database and Networkanalyst platform were used to construct gene-gene and TFs-gene interaction network diagrams respectively to predict gene functions and find key transcription factors. Finally, the correlation between key genes and immune cell subtypes was performed by Spearman analysis.

Research results

A total of 425 DEGs were screened out from the AF dataset, and 4,128 DEGs were screened out from the CKD dataset. After taking the intersection of the two, 82 co-expressed DEGs were obtained. The results of GO enrichment analysis of DEGs showed that the genes were mainly enriched in biological processes such as secretory granule lumen, blood microparticles, complement binding, and antigen binding. KEGG functional enrichment analysis indicated that the genes were mainly enriched in pathways such as the complement coagulation cascade, systemic lupus erythematosus, and Staphylococcus aureus infection. The top 15 DEGs were obtained through the MCC topological algorithm of Cytoscape software. Subsequently, based on LASSO regression and RF algorithm, the key characteristic genes of the 15 co-expressed DEGs of AF and CKD were further screened, and by taking the intersection through Venn diagrams, five key characteristic genes were finally obtained: PPBP, CXCL1, LRRK2, RGS18, RSAD2. ROC curves were constructed to calculate the area under the curve to verify the diagnostic efficacy of the key characteristic genes for diseases. The results showed that RSAD2 had the highest diagnostic value for AF, and the diagnostic values of PPBP, CXCL1, and RSAD2 for CKD were all at a relatively strong verification level. Based on AUC >0.7, co-expressed key genes with strong diagnostic efficacy were obtained: PPBP, CXCL1, RSAD2. The results of the GeneMANIA online database showed that the two biomarkers, BBPB and CXCL1, mainly had functional interactions with cytokine activity, chemokine receptor activity, cell response to chemokines, neutrophil migration, response to chemokines, granulocyte chemotaxis, and granulocyte migration. The TFs-gene regulatory network identified FOXC1, FOXL1, and GATA2 as the main transcription factors of the key characteristic genes. Finally, through immune infiltration analysis, the results indicated that there were various immune cell infiltrations in the development processes of AF and CKD.

Research conclusion

PPBP, CXCL1, and RSAD2 are key genes closely related to the occurrence and development processes between AF and CKD. Among them, the CXCLs/CXCR signaling pathway play a crucial role in the development processes of the two diseases likely. In addition, FOXC1, FOXL1, and GATA2 may be potential therapeutic targets for AF combined with CKD, and the development of the diseases is closely related to immune cell infiltration.

Mitochondrial injury and complement dysregulation are drivers of pathological inflammation in viral myocarditis

Enteroviruses cause nearly 1 billion global infections annually and are associated with a diverse array of human illnesses. Among these, myocarditis and the resulting chronic inflammation have been recognized as major contributing factors to virus-induced heart failure. Despite our growing understanding, very limited therapeutic strategies have been developed to address the pathological consequences of virus-induced chronic innate immune activation. Coxsackievirus B3 (CVB3) was used as a model cardiotropic enterovirus. We leveraged in vitro cell-based studies to investigate cardiomyocyte and macrophage interaction during CVB3 infection, as well as animal studies and unique human cardio specimens to evaluate mechanisms of viral heart injury. We present evidence that viral myocarditis is in part exacerbated by pathological activation of the complement pathway in cells, mice, and human cardiac tissues. We demonstrate unique cell type-specific responses to viral infection that are exacerbated by mitochondrial injury in cardiomyocytes and NFκB-dependent pro-inflammatory response in macrophages. Macrophages are robustly activated by damage-associated mitochondrial components, including mitochondrial proteins and lipid extracts. Mechanistically, we identify complement protective factors CD59/protectin and CD55/DAF as novel targets of viral proteinase that acts to release the brakes on complement-mediated autoinjury. Collectively, our study highlights a novel mechanism that can act as a potential contributor to CVB3 pathogenesis through mitochondrial injury-mediated autoimmunity.

IMPORTANCE

This study sheds light on how enteroviruses, specifically coxsackievirus B3, may contribute to heart failure by triggering harmful immune responses in the heart. We discovered that viral infections in heart cells cause mitochondrial damage, which in turn activates a destructive immune response involving the complement system. This immune activation is one of the significant contributors that lead to further injury of heart tissues, worsening the damage caused by the virus. Additionally, we identified key protective molecules that are targeted and disrupted by the virus, allowing the immune system to attack the heart even more aggressively. Understanding these mechanisms may provide additional insights into how viral infections can lead to chronic heart conditions and suggests potential therapeutic targets to prevent or reduce heart damage in patients affected by viral myocarditis.

Inflammatory Cell-Targeted Delivery Systems for Myocardial Infarction Treatment

Myocardial infarction (MI) is a cardiovascular disease (CVD) with high morbidity and mortality worldwide, which is a serious threat to human life and health. Inflammatory and immune responses are initiated immediately after MI, and unbalanced inflammation post-MI can lead to cardiac dysfunction, scarring, and ventricular remodeling, emphasizing the critical need for an effective inflammation-regulating treatment. With the development of novel therapies, the drug delivery system specific to inflammatory cells offers significant potential. In this review, we introduce immune cells and fibroblasts involved in the development of MI and summarize the newly developed delivery systems related to the use of injectable hydrogels, cardiac patches, nanoparticles, and extracellular vesicles (EVs). Finally, we highlight the recent trends in the use of inflammatory cell-targeting drug delivery systems involving different strategies that facilitate the effective treatment of MI.

Protective Effects of Low-Intensity Pulsed Ultrasound on Cardiac Electrophysiological Function in a Rat Model of Ischemic Cardiomyopathy

BACKGROUND

Ischemic cardiomyopathy (ICM) is the end stage of ischemic heart disease, in which ventricular remodeling contributes to a fatal ventricular arrhythmia, worsens heart function and unfavorable outcomes, and is related to persistent chronic inflammation. Low-intensity pulsed ultrasound (LIPUS) is an effective treatment modality for osteoarthropathy and has been illustrated to regulate the overactive inflammatory response in various diseases. Here, we aim to investigate whether LIPUS can perform cardiac protective effects in ICM and explore its possible mechanism.

METHODS

The left anterior descending artery of adult male Sprague-Dawley rats was ligated for 4 weeks to develop ICM and then treated with LIPUS. Vagotomy was applied to suppress the cholinergic anti-inflammatory pathway. Cardiac-specific Cav-1 (caveolin-1) overexpression in ICM on arrhythmias, excitation-contraction coupling, and cardiac remodeling was investigated using the intramyocardial injection of an adeno-associated virus serotype 9 system.

RESULTS

The results showed that LIPUS alleviated ventricular remodeling, improved cardiac electrophysiological function, and reduced the cardiac expression of collagens and inflammatory cytokines. Vagotomy suppressed the improvement of LIPUS. The overexpression of Cav-1 reset the influence of vagotomy.

CONCLUSIONS

We found that LIPUS had a direct effect on regional anti-inflammation and antifibrosis, improved cardiac autonomic function and heart failure, protected the Cx43 (connexin-43) protein, and reduced the risk of malignant arrhythmia during ICM. The cholinergic anti-inflammatory pathway was one of the potential critical mechanisms involved, and Cav-1 might play an important role downstream. Our study provided a new, promising, and noninvasive strategy for treating ICM.

Adhered macrophages as an additional marker of cardiomyocyte injury in biopsies of patients with dilated cardiomyopathy

Background

Macrophage accumulation found in biopsy specimens of patients with dilated cardiomyopathy (DCM) has been thought to reflect chronic myocarditis. However, it is unsettled whether they are responsible for the active or persistent phase of the disease.

Objective

The aim of this study was to count the number of macrophages in relation to plasma concentrations of cardiac troponin T (cTnT).

Methods

We studied the biopsies of 181 patients with DCM by immunohistochemistry using anti-CD68(+) antibodies. The total number of CD68(+) and the number of CD68(+) cells attached to injured cardiomyocytes were counted and presented as the number of cells/mm2.

Results

Two expression patterns of CD68(+) macrophages were observed: those localized freely in the interstitial space only, and the cells attached to injured cardiomyocytes. As regards macrophages adhered to injured cardiomyocytes, 72 out of 181 (39.8%) patients presented these cells in the biopsy sections. Both the total number of CD68(+) macrophages and the number of CD68(+) cells directly adhered correlated negatively with cTnT in the serum of DCM patients (Spearman's rho, r = -0.45, P < 0.001 and r = -0.31, P = 0.009, respectively).

Conclusion

Macrophages attached to injured cardiomyocytes may reflect chronic (ongoing) inflammation in the myocardium.

Melatonin Attenuates Cardiac Dysfunction and Inflammation in Dilated Cardiomyopathy via M2 Macrophage Polarization

ABSTRACT

Melatonin is a neuroendocrine hormone that exerts protective effects on the heart. Increasing evidence suggests that macrophage M2-type polarization improves myocardial regeneration and repair. Therefore, this study investigated whether melatonin ameliorates dilated cardiomyopathy (DCM) by modulating M2-type polarization. DCM mice were established by induction with doxorubicin and then treated with melatonin. Cardiac dysfunction was determined by measuring left ventricular ejection fraction and left ventricular internal dimensions at end-diastole and end-systole. Heart injury and fibrosis were determined by hematoxylin and eosin staining and Sirius Red staining, respectively. Serum concentrations of melatonin, tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and interleukin-6 (IL-6) were measured through enzyme-linked immunosorbent assays. M2-type macrophages were analyzed by flow cytometry. Relative mRNA and protein levels were determined by reverse transcription quantitative polymerase chain reaction and Western blotting, respectively. Circulating melatonin levels were significantly decreased in DCM mice and were associated with left ventricular ejection fraction. Treatment with melatonin markedly ameliorated cardiac dysfunction, improved survival, and alleviated pathologic changes and collagen deposition in DCM mice. Furthermore, melatonin-treated DCM mice displayed lower serum and cardiac levels of IL-1β, IL-6, and TNF-α, as well as higher number of M2-type macrophages in cardiac tissue, indicating that melatonin treatment could decrease inflammatory responses and facilitate M2 macrophage polarization in DCM mice. Thus, melatonin treatment alleviated cardiac dysfunction and inflammatory responses by promoting M2 macrophage polarization in the DCM mouse model.

Preclinical models of cardiotoxicity from immune checkpoint inhibitor therapy

Immune checkpoint inhibitor (ICI) therapy represents a ground-breaking paradigm in cancer treatment, harnessing the immune system to combat malignancies by targeting checkpoints such as cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed cell death protein 1 (PD-1). The use of ICI therapy generates distinctive immune-related adverse events (irAEs) including cardiovascular toxicity, necessitating targeted research efforts. This comprehensive review explores preclinical models dedicated to ICI-mediated cardiovascular complications including myocarditis. Tailored preclinical models of ICI-mediated myocardial toxicities highlight the key role of CD8+ T cells, emphasizing the profound impact of immune checkpoints on maintaining cardiac integrity. Cytokines and macrophages were identified as possible driving factors in disease progression, and at the same time, initial data on possible cardiac antigens responsible are emerging. The implications of contributing factors including thoracic radiation, autoimmune disorder, and the presence of cancer itself are increasingly understood. Besides myocarditis, mouse models unveiled an accelerated progression of atherosclerosis, adding another layer for a thorough understanding of the diverse processes involving cardiovascular immune checkpoint signalling. This review aims to discuss current preclinical models of ICI cardiotoxicity and their potential for improving enhanced risk assessment and diagnostics, offering potential targets for innovative cardioprotective strategies. Lessons from ICI therapy can drive novel approaches in cardiovascular research, extending insights to areas such as myocardial infarction and heart failure.

Myocardial Inflammation in Cardiac Transthyretin Amyloidosis: Prevalence and Potential Prognostic Implications

BACKGROUND

Despite previous histopathologic evidence for its presence, the role of myocardial inflammation in the development and progression of cardiac transthyretin amyloidosis (ATTR-CA) remains insufficiently understood. Thus, this study sought to characterize the prevalence and potential prognostic implications of myocardial inflammation in ATTR-CA.

METHODS

A retrospective observational study including patients with ATTR-CA diagnosed by endomyocardial biopsy was conducted. Myocardial inflammation was diagnosed through a review of routine endomyocardial biopsy reports. Baseline characteristics were compared using the Mann-Whitney U test and the Pearson χ2 test. Clinical outcomes were monitored via follow-up visits or telephone calls. Primary outcomes were all-cause death and a composite end point of all-cause death or heart failure hospitalization. Kaplan-Meier analyses, as well as univariable and age- and sex-adjusted multivariable Cox regression analyses, were used to assess differences in overall and composite end point-free survival between patients with ATTR-CA with and without myocardial inflammation.

RESULTS

A total of 103 patients with ATTR-CA (100 wild type; 3 variant) were enrolled. Median follow-up was 18.2 (8.0-31.1) months. Myocardial inflammation was prevalent in 32% (n=33/103) of patients with ATTR-CA. Among evaluable patients with myocardial inflammation, 96% (n=26/27) and 31% (n=9/29) had elevated CD68 (clusters of differentiation 68)-positive macrophage and CD3 (clusters of differentiation 3)-positive T-cell counts, respectively. Overall survival (P=0.017) and composite end point-free survival (P=0.014) were significantly impaired in patients with ATTR-CA with myocardial inflammation (n=33) compared with those without (n=70). Statistical significance for both associations was sustained after adjustment for age and sex, yielding adjusted hazard ratios of 4.72 (95% CI, 1.33-16.71; P=0.016) and 2.30 (95% CI, 1.04-5.11; P=0.041) for all-cause death and the composite end point, respectively.

CONCLUSIONS

Our findings affirm previous evidence that myocardial inflammation is present in approximately one-third of all patients with ATTR-CA. Moreover, we provide first data indicating that myocardial inflammation may be associated with a higher risk of death and heart failure hospitalizations in ATTR-CA.

Autoimmunity in Cardiomyopathy-Induced Heart Failure and Cardiac Autoantibody Removal by Immunoadsorption

There is increasing evidence that β1-adrenoreceptor autoantibody (β1AR-AAb) elimination can break the vicious circle induced by certain pathological conditions associated with alteration of the physiological self-tolerance, followed by generation of such AAbs and activation of cell-mediated immune processes directed against the myocardium. Concerning this, the present narrative review article provides an updated overview of the state of knowledge about the role of auto-immunity in the etiopathogenesis of cardiomyopathies, with a particular focus on immunoadsorption (IA) therapy for β1AR-AAb-positive adult patients with a dilated cardiomyopathy (DCM)-associated refractory heart failure (HF). Among many relevant findings, the increasing prevalence (up to 97%) of β1AR-AAb-positive patients related to the aggravation of HF, the high prevalence (between 84% and 91%) of HF patients in which IA can reduce to a minimum any increased β1AR-AAb level, as well as the high prevalence (about 80%) of responders to the IA-induced normalization of β1AR-AAb levels by long-term improvement in LV ejection fraction with increase in LV stroke volume and cardiac output, are of particular relevance. Given that after the elimination of β1AR-AAbs in potential candidates for heart transplantation (HTx), the post-IA 3- and 5-year HTx-/mechanical support-free survival probability reached 80% and 63-69%, respectively, the good tolerability of IA and the possibility to repeat that therapy also in elderly persons strongly suggest that in appropriately selected patients, this therapy deserves much more attention in the future.

The Role of Signalling Pathways in Myocardial Fibrosis in Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is the most prevalent hereditary cardiovascular disorder, characterised by left ventricular hypertrophy and cardiac fibrosis. Cardiac fibroblasts, transformed into myofibroblasts, play a crucial role in the development of fibrosis. However, interactions between fibroblasts, cardiomyocytes, and immune cells are considered major mechanisms driving fibrosis progression. While the disease has a strong genetic background, its pathogenetic mechanisms remain complex and not fully understood. Several signalling pathways are implicated in fibrosis development. Among these, transforming growth factor-beta and angiotensin II are frequently studied in the context of cardiac fibrosis. In this review, we summarise the most current evidence on the involvement of signalling pathways in the pathogenesis of HCM. Additionally, we discuss the potential role of monitoring pro-fibrotic molecules in predicting clinical outcomes in patients with HCM.

Active ingredients of traditional Chinese medicine inhibit NOD-like receptor protein 3 inflammasome: a novel strategy for preventing and treating heart failure

Heart failure (HF) has emerged as a significant global public health challenge owing to its high rates of morbidity and mortality. Activation of the NOD-like receptor protein 3 (NLRP3) inflammasome is regarded as a pivotal factor in the onset and progression of HF. Therefore, inhibiting the activation of the NLRP3 inflammasome may represent a promising therapeutic approach for preventing and treating HF. The active ingredients serve as the foundation for the therapeutic effects of traditional Chinese medicine (TCM). Recent research has revealed significant advantages of TCM active ingredients in inhibiting the activation of the NLRP3 inflammasome and enhancing cardiac structure and function in HF. The study aimed to explore the impact of NLRP3 inflammasome activation on the onset and progression of HF, and to review the current advancements in utilizing TCM active ingredients to inhibit the NLRP3 inflammasome for preventing and treating HF. This provides a novel perspective for the future development of precise intervention strategies targeting the NLRP3 inflammasome to prevent and treat HF.

Documentation of lead exposure-associated comorbidity among 4538 workers in China

BACKGROUND

Systematic documentation of morbidity with exposure assessment in a large group of lead (Pb)-exposed workers in China.

METHODS

Using the cluster sampling method, Pb-exposed workers were recruited from a factory in the Henan Province, China. The morbidity information and blood lead concentration (BLC) from each worker were collected. Relationships between the two sets of data were analyzed using the logistic regression and restricted cubic spline (RCS) models.

RESULTS

Among the 4538 recruited workers, there were 2780 males and 1758 females, with a median age of 34 years old, and BLC ranging from 7.70 to 722.70 μg/l. Among them, 1247 (27.4%) had multiple morbidities (comorbidity). Those with the highest BLC showed a 1.79-fold (significant) increase in comorbidities compared to those with the lowest BLC (95% confidence interval = 1.43, 2.25; p < 0.001). In addition, the comorbidities exhibited a BLC dose-response relationship (p < 0.001), after adjusting for potential confounding factors. The RCS curve analysis revealed a nonlinear relationship between BLC and risk of comorbidity (p-overall < 0.001, and p-nonlinear < 0.001). Sensitivity analysis further confirmed the dose-response relationship between BLC and the risk of developing comorbidities. Additionally, the data indicate that female workers were more susceptible to comorbidities.

CONCLUSION

Our study demonstrates that comorbidity was prevalent and was dose-dependent among lead exposed workers.

The interplay of senescence and MMPs in myocardial infarction: implications for cardiac aging and therapeutics

Aging is associated with a marked increase in cardiovascular diseases, such as myocardial infarction (MI). Cellular senescence is also a crucial factor in the development of age-related MI. Matrix metalloproteinases (MMPs) interaction with cellular senescence is a critical determinant of MI development and outcomes, most notably in the aged heart. After experiencing a heart attack, senescent cells exhibit a Senescence-Associated Secretory Phenotype (SASP) and are involved in tissue regeneration and chronic inflammation. MMPs are necessary for extracellular matrix proteolysis and have a biphasic effect, promoting early heart healing and detrimental change if overexpressed shortly. This review analyses the complex connection between senescence and MMPs in MI and how it influences elderly cardiac performance. Critical findings suggest that increasing cellular senescence in aged hearts elevates MMP activity and aggravates extended ventricular remodeling and dysfunction. Additionally, we explore potential therapeutics that address MMPs and senescence to enhance old MI patient myocardial performance and regeneration.

VASN knockout induces myocardial fibrosis in mice by downregulating non-collagen fibers and promoting inflammation

Myocardial fibrosis (MF) is an important cause of heart failure and cardiac arrest. Vasorin knockout (VASN-/-) leads to pathological cardiac hypertrophy (PCH); however, it is not yet clear whether this PCH transitions to MF in mice. VASN-knockout mice showed typical pathological, imaging, and molecular features of MF upon hematoxylin and eosin staining, Masson staining, Sirius red staining, quantitative polymerase chain reaction (qPCR), immunohistochemistry-paraffin (IHC-P), and immunofluorescence analyses. RNA was extracted from mouse heart tissue, identified, and sequenced in vitro. Differential analysis of the genes showed that the extracellular matrix (ECM) genes (COL6A1, COL9A1, and FRAS1) had strong correlations while their expression levels were significantly reduced by qPCR, IHC-P, and Western blotting. The expression levels of the ECM genes were significantly reduced but those of the inflammatory factors (IL1β and IL6) were significantly upregulated in the heart tissues of VASN-knockout mice. These preliminary results reveal that VASN knockout induces MF by regulating the non-collagen fibers and inflammation.

Is Lung Disease a Risk Factor for Sudden Cardiac Death? A Comparative Case-Control Histopathological Study

BACKGROUND/OBJECTIVES

Sudden cardiac death (SCD) constitutes approximately 50% of cardiovascular mortality. Numerous studies have established an interrelation and a strong association between SCD and pulmonary diseases, such as chronic obstructive pulmonary disease (COPD). The aim of this study is to examine the presence of more pronounced cardiopulmonary histopathological changes in individuals who died from SCD compared to the histopathological changes in those who died from violent deaths, in two groups with comparable demographic characteristics, age and sex.

METHODS

This retrospective case-control study investigated the histopathological changes in cardiac and pulmonary tissues in two cohorts, each comprising 40 cases of SCD and 40 cases of violent death (self-inflicted hanging). Forensic autopsies were conducted at the Maramureș County Forensic Medicine Service, Romania, between 2019 and 2020.

RESULTS

The mean ages recorded were 43.88 years (SD 5.49) for the SCD cohort and 41.98 years (SD 8.55) for the control cohort. In the SCD cases, pulmonary parenchyma exhibited inflammatory infiltrate in 57.5% (23), fibrosis in 62.5% (25), blood extravasation in 45% (18), and vascular media thickening in 37.5% (15), compared to the control cohort, where these parameters were extremely low. In myocardial tissue, fibrosis was identified in 47.5% (19) and subendocardial adipose tissue in 22.5% (9) of the control cohort.

CONCLUSIONS

A close association exists between SCD and the histopathological alterations observed in the pulmonary parenchyma, including inflammation, fibrosis, emphysema, blood extravasation, stasis, intimal lesions, and vascular media thickening in intraparenchymal vessels. Both the histopathological modifications in the pulmonary parenchyma and vessels, as well as those in myocardial tissue, were associated with an increased risk of SCD, ranging from 2.17 times (presence of intimal lesions) to 58.50 times (presence of interstitial and perivascular inflammatory infiltrate in myocardial tissue).

Emerging Role of Macrophage-Fibroblast Interactions in Cardiac Homeostasis and Remodeling

As major noncardiomyocyte components in cardiac tissues, macrophages and fibroblasts play crucial roles in maintaining cardiac homeostasis, orchestrating reparative responses after cardiac injuries, facilitating adaptive cardiac remodeling, and contributing to adverse cardiac remodeling, owing to their inherent heterogeneity and plasticity. Recent advances in research methods have yielded novel insights into the intricate interactions between macrophages and fibroblasts in the cardiac context. This review aims to comprehensively examine the molecular mechanisms governing macrophage-fibroblast interactions in cardiac homeostasis and remodeling, emphasize recent advancements in the field, and offer an evaluation from a translational standpoint.

OGT-mediated O-GlcNAcylation regulates macrophage polarization in heart failure via targeting IRF1

BACKGROUND

Heart failure (HF) is a syndrome with complex etiology and high mortality in the world. Macrophage-related inflammation is involved in HF development. O-GlcNAcylation is a post-translational modification that affects pathological processes. This study aimed to investigate the role of O-GlcNAcylation in HF, especially its effect on macrophage polarization.

METHODS

Raw264.7 cells were treated with lipopolysaccharide (LPS) to induce pro-inflammatory macrophages. HF mice were generated by transverse aortic constriction (TAC). After knockdown of OGT or overexpressing IRF1, macrophage polarization was evaluated using quantitative real-time polymerase chain reaction and flow cytometry. Underlying mechanism was analyzed using bioinformatic analysis, co-immunoprecipitation (co-IP), IP, and western blotting.

RESULTS

The results showed that O-GlcNAcylation and OGT levels were high in LPS-treated Raw264.7 cells. OGT knockdown inhibited pro-inflammatory macrophage polarization and promoted anti-inflammatory macrophage polarization caused by LPS, and alleviated TAC-induced cardiac dysfunction and fibrosis. Mechanistically, OGT silence suppressed O-GlcNAcylation of IRF1 at Ser (S)283 site. IRF1 overexpression reversed macrophage polarization modulated by OGT knockdown.

CONCLUSION

Silencing of OGT promotes macrophage polarization from pro-inflammatory to anti-inflammatory phenotype to alleviate HF through O-GlcNAcylation of IRF1. The findings suggest that O-GlcNAcylation has the potential to treat HF.

Neonatal heart tissue-derived EVs alleviate adult ischemic cardiac injury via regulating the function of macrophages and cardiac regeneration in murine models

Previous studies confirmed the regenerative capacity of the mammalian neonatal heart. We recently found that adult heart tissue-derived EVs can protect the heart from myocardial ischemia-reperfusion (I/R). However, the role of EVs from neonatal heart tissue in cardiac healing post-ischemia remains unclear. In the present study, we revealed that intramyocardial administration of neonatal cardiac tissue-derived EVs (ncEVs) alleviated cardiac inflammation, mitigated reperfusion injury, and improved cardiac function in murine I/R models. In vitro, ncEVs inhibited M1 polarization of macrophages induced by LPS while up-regulated their phagocytic function via the miR-133a-3p-Ash1l signaling pathway. Moreover, the administration of ncEVs contributed to cardiac angiogenesis and improved cardiac function in murine myocardial infarction models. Collectively, these results suggested that neonatal heart-derived EVs can regulate the function of macrophages and contribute to cardiac regeneration and function recovery in murine cardiac ischemic models. Therefore, the derivatives in neonatal heart tissue-derived EVs might serve as a potential therapeutic strategy in ischemic diseases.

Macrophages after myocardial infarction: Mechanisms for repairing and potential as therapeutic approaches

Macrophages - one of the crucial immune cells, are recruited to the cardiac tissue by chemokines, cytokines and upregulated endothelial adhesion molecules after myocardial infarction (MI). During the course of inflammation in the cardiac tissue, necrotic cells and matrix debris is phagocytosed by M1 macrophages. During the resolution phase of cardiac inflammation, M2 macrophages promote cardiac recovery. Suppression or over expression of both the M1 and M2 macrophage subtypes significantly affect the reparation of infarction. Stem cells therapy, cytokine regulation and immune cells therapy are considered as effective interventions to regulate the phenotypic transformation of cardiac macrophages after MI. Intervention with macrophages in the myocardium has shown unique advantages. In this review, the mechanisms and role of macrophages in the development of MI are elaborated in detail, the promising therapeutic methods for regulating macrophage phenotypes, their limitations and possible future research directions are discussed.

Pathophysiology of Angiotensin II-Mediated Hypertension, Cardiac Hypertrophy, and Failure: A Perspective from Macrophages

Heart failure is a complex syndrome characterized by cardiac hypertrophy, fibrosis, and diastolic/systolic dysfunction. These changes share many pathological features with significant inflammatory responses in the myocardium. Among the various regulatory systems that impact on these heterogeneous pathological processes, angiotensin II (Ang II)-activated macrophages play a pivotal role in the induction of subcellular defects and cardiac adverse remodeling during the progression of heart failure. Ang II stimulates macrophages via its AT1 receptor to release oxygen-free radicals, cytokines, chemokines, and other inflammatory mediators in the myocardium, and upregulates the expression of integrin adhesion molecules on both monocytes and endothelial cells, leading to monocyte-endothelial cell-cell interactions. The transendothelial migration of monocyte-derived macrophages exerts significant biological effects on the proliferation of fibroblasts, deposition of extracellular matrix proteins, induction of perivascular/interstitial fibrosis, and development of hypertension, cardiac hypertrophy and heart failure. Inhibition of macrophage activation using Ang II AT1 receptor antagonist or depletion of macrophages from the peripheral circulation has shown significant inhibitory effects on Ang II-induced vascular and myocardial injury. The purpose of this review is to discuss the current understanding in Ang II-induced maladaptive cardiac remodeling and dysfunction, particularly focusing on molecular signaling pathways involved in macrophages-mediated hypertension, cardiac hypertrophy, fibrosis, and failure. In addition, the challenges remained in translating these findings to the treatment of heart failure patients are also addressed.

Construction of an adverse outcome pathway for the cardiac toxicity of bisphenol a by using bioinformatics analysis

Bisphenol A (BPA), a common endocrine disruptor, has shown cardiovascular toxicity in several epidemiological studies, as well as in vivo and in vitro experimental studies. However, the related adverse outcome pathway (AOP) of BPA toxicity remains unraveled. This study aimed to develop an AOP for the cardiac toxicity of BPA through bioinformatics analysis. The interactions among BPA, genes, phenotypes, and cardiac toxicity were retrieved from several databases, including the Comparative Toxicogenomics Database, Computational Toxicology, DisGeNet, and MalaCards. The target genes and part of target phenotypes were obtained by Venn analysis and literature screening. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis were performed for target genes by using the DAVID online analysis tool to obtain other target phenotypes. AOP hypotheses from BPA exposure to heart disease were established and evaluated comprehensively by a quantitative weight of evidence (QWOE) method. The target genes included ESR2, MAPK1, TGFB1, and ESR1, and the target phenotypes included heart contraction, cardiac muscle contraction, cellular Ca2+ homeostasis, cellular metabolic process, heart development, etc. Overall, the AOP of BPA cardiac toxicity was deduced to be as follows. Initially, BPA bound with ERα/β and then activated the MAPK, AKT, and IL-17 signaling pathways, leading to Ca2+ homeostasis disorder and increased inflammatory response. Subsequently, cardiac function was impaired, causing coronary heart disease, arrhythmia, cardiac dysplasia, and other heart diseases. According to the Bradford-Hill causal considerations, the score of AOP by QWOE was 69, demonstrating a moderate confidence and providing clues on cardiotoxicity-assessment procedure and further studies on BPA.

Mesenchymal precursor cells reduce mortality and major morbidity in ischaemic heart failure with inflammation: DREAM-HF

AIMS

Progressive heart failure with reduced ejection fraction (HFrEF) is adversely affected by alterations in the myocardial balance between bone marrow-derived pro-inflammatory cardiac macrophages and embryo-derived reparative cardiac resident macrophages. Mesenchymal precursor cells (MPCs) may restore this balance and improve clinical outcomes when inflammation is present. The purpose was to (i) identify risk factors for cardiovascular death (CVD) in control patients with HFrEF in the DREAM-HF trial, and (ii) determine if MPCs improve major clinical outcomes (CVD, myocardial infarction [MI], stroke) in high-risk patients with ischaemic HFrEF and inflammation.

METHODS AND RESULTS

Cause-specific regression analyses were used to identify CVD risk factors in DREAM-HF control patients. Aalen-Johansen cumulative incidence curves were used to examine CVD, 2-point major adverse cardiovascular events (MACE) (MI or stroke), and 3-point MACE (CVD or MI or stroke) by treatment group in ischaemic vs non-ischaemic HFrEF and in patients with or without baseline inflammation. In control DREAM-HF patients, factors portending the greatest risk for CVD were inflammation (baseline plasma high-sensitivity C-reactive protein ≥2 mg/L; p = 0.003) and ischaemic HFrEF aetiology (p = 0.097), with increased CVD risk of 61% and 38%, respectively. Over 30-month mean follow-up, MPCs reduced 2-point and 3-point MACE by 88% (p = 0.005) and 52% (p = 0.018), respectively, in patients with ischaemic HFrEF and inflammation compared to controls.

CONCLUSION

Ischaemic aetiology and inflammation were identified as major risk factors for MACE in control DREAM-HF patients. A single intramyocardial MPC administration produced the most significant, sustained reduction in 2-point and 3-point MACE in patients with ischaemic HFrEF and inflammation.

Neutrophil-Driven M2-Like Macrophages Are Critical for Skin Fibrosis in a Systemic Sclerosis Model

Systemic sclerosis (SSc) is a challenging autoimmune disease characterized by progressive fibrosis affecting the skin and internal organs. Despite the known infiltration of macrophages and neutrophils, their precise contributions to SSc pathogenesis remain elusive. In this study, we elucidated that CD206hiMHCIIlo M2-like macrophages constitute the predominant pathogenic immune cell population in the fibrotic skin of a bleomycin-induced SSc mouse model. These cells emerged as pivotal contributors to the profibrotic response by orchestrating the production of TGF-β1 through a MerTK signaling-dependent manner. Notably, we observed that neutrophil infiltration was a prerequisite for accumulation of M2-like macrophages. Strategies such as neutrophil depletion or inhibition of CXCR1/2 were proven effective in reducing M2-like macrophages, subsequently mitigating SSc progression. Detailed investigations revealed that in fibrotic skin, neutrophil-released neutrophil extracellular traps were responsible for the differentiation of M2-like macrophages. Our findings illuminate the significant involvement of the neutrophil-macrophage-fibrosis axis in SSc pathogenesis, offering critical information for the development of potential therapeutic strategies.

Mechanisms of doxorubicin-induced cardiac inflammation and fibrosis; therapeutic targets and approaches

Doxorubicin plays a pivotal role in the treatment of various malignancies. Despite its efficacy, the cardiotoxicity associated with doxorubicin limits its clinical utility. The cardiotoxic nature of doxorubicin is attributed to several mechanisms, including its interference with mitochondrial function, the generation of reactive oxygen species (ROS), and the subsequent damage to cardiomyocyte DNA, proteins, and lipids. Furthermore, doxorubicin disrupts the homeostasis of cardiac-specific transcription factors and signaling pathways, exacerbating cardiac dysfunction. Oxidative stress, cell death, and other severe changes, such as mitochondrial dysfunction, activation of pro-oxidant enzymes, the renin-angiotensin system (RAS), endoplasmic reticulum (ER) stress, and infiltration of immune cells in the heart after treatment with doxorubicin, may cause inflammatory and fibrotic responses. Fibrosis and inflammation can lead to a range of disorders in the heart, resulting in potential cardiac dysfunction and disease. Various adjuvants have shown potential in preclinical studies to mitigate these challenges associated with cardiac inflammation and fibrosis. Antioxidants, plant-based products, specific inhibitors, and cardioprotective drugs may be recommended to alleviate cardiotoxicity. This review explores the complex mechanisms of doxorubicin-induced heart inflammation and fibrosis, identifies possible cellular and molecular targets, and investigates potential substances that could help reduce these harmful effects.

Black-Phosphorus-Reinforced Injectable Conductive Biodegradable Hydrogel for the Delivery of ADSC-Derived Exosomes to Repair Myocardial Infarction

Myocardial infarction (MI) remains one of the leading causes of death globally, necessitating innovative therapeutic strategies for effective repair. Conventional treatment methods such as pharmacotherapy, interventional surgery, and cardiac transplantation, while capable of reducing short-term mortality rates, still face significant challenges in post-MI repair including the restoration of intercellular biological and electrical signaling. This study presents a novel exosome-loaded conductive hydrogel designed to enhance myocardial repair by concurrently improving biological and electrical signals. Adipose-derived stem cell (ADSC) exosomes, encapsulated within a hyaluronic acid-dopamine (HA-DA) hydrogel, were employed to promote angiogenesis and inhibit inflammation. Incorporating black phosphorus (BP) into the hydrogel improved its electrical conductivity, thereby restoring electrical signal transmission in the infarcted myocardium and preventing arrhythmias. In vitro and in vivo experiments demonstrated that the exosome-loaded conductive hydrogel significantly enhanced cardiac function recovery by accelerating angiogenesis, reducing inflammation, and increasing electrical activity between myocardial cells. The hydrogel exhibited excellent biocompatibility, biodegradability, and sustained release of exosomes, ensuring prolonged therapeutic effects. This integrated approach resulted in notable improvements in the left ventricular ejection fraction, reduced fibrosis, and increased neovascularization. The combination of bioactive exosomes and a conductive hydrogel presents a promising therapeutic strategy for myocardial infarction repair.

Molecular imaging along the heart-kidney axis

Cardiorenal syndrome (CRS) involves bidirectional crosstalk between the failing heart and the kidneys. Depending on the primum movens (primary cardiac or renal injury), systems-based interactions in the secondary affected organ may include pro-fibrotic signaling, overzealous inflammation, impaired nerve integrity or overactivity of specific renal transporters mediating glucose absorption. Those pathophysiological pillars can be investigated by molecular imaging using SPECT or PET agents. Targeted whole-body molecular imaging may allow for a) systems-based analysis along the heart-kidney axis, b) may provide prognostic information on longitudinal organ-based functional decline or c) may be used for guidance of reparative intervention based on peak activation identified on PET (paradigm of cardiorenal theranostics). We will discuss the current state of translational molecular imaging for CRS, along with future clinical aspects in the field.

Identification and Verification of Potential Markers Related to Myocardial Fibrosis by Bioinformatics Analysis

Mounting evidence indicates that myocardial fibrosis (MF) is frequently intertwined with immune and metabolic disorders. This comprehensive review aims to delve deeply into the crucial role of immune-related signature genes in the pathogenesis and progression of MF. This exploration holds significant importance as understanding the underlying mechanisms of MF is essential for developing effective diagnostic and therapeutic strategies. The dataset GSE9735 about myocardial fibrosis and non-fibrosis was downloaded from GEO database. Differentially expressed genes (DEGs) were identified by 'limma' package in R software. Then, the biological function of DEG was determined by gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. XCell was used to estimate the composition pattern of matrix and immune cells. Protein-protein interaction (PPI) network was constructed based on STRING analysis software, and Hub genes were screened and functional modules were analyzed. The correlation between hub genes and immune cell subtypes was analyzed. Hub genes with |correlation coefficient|> 0.45 and p-value < 0.05 were used as characteristic biomarkers. Finally, the logistic regression model is used to verify the three markers in the training set and verification set (GSE97358 and GSE225336). A total of 635 DEGs were identified. Functional enrichment analysis shows that inflammation and immune response, extracellular matrix and structural remodeling play an important role in the pathological mechanism of MF. Immune cell infiltration analysis showed that immune cells (Plasma cells, Eosinophils, Chondrocytes and Th2 cells) significantly changed in MF pathological conditions. In PPI network analysis, IL1β, TTN, PTPRC, IGF1, ALDH1A1, CYP26A1, ALDH1A3, MYH11, CSF1R and CD80 were identified as hub genes, among which IL1β, CYP26A1 and GNG2 were regarded as immune-related characteristic markers. The AUC scores of the three biomarkers are all above 0.65, which proves that they have a good discrimination effect in MF. In this study, three immune-related genes were identified as diagnostic biomarkers of MF, which provided a new perspective for exploring the molecular mechanism of MF. This study takes a comprehensive approach to understanding the intricate relationship between myocardial fibrosis and immune metabolism. By identifying key immune-related biomarkers, this study not only reveals the molecular basis of myocardial fibrosis but also paves the way for the development of novel diagnostic tools and therapeutic strategies. These findings are critical for improving patient prognosis and may have broader implications for studying and treating other cardiovascular diseases associated with immune dysregulation.

Scar-Related Ventricular Tachycardia: Pathophysiology, Diagnosis, and Management

Scar-related ventricular tachycardia (VT) commonly results from scarring in the myocardium, principally produced by antecedent myocardial infarction, cardiomyopathy, or prior cardiac surgery. The resultant arrhythmogenic substrate from scarred tissue and the alteration of normal cardiac electrical conduction predispose patients to reentrant circuits, followed by VT. This literature review synthesizes current research on pathophysiology, diagnostic methods, and treatment modalities of scar-related VT. The primary contents of the review are descriptions of the mechanisms through which myocardial fibrosis results in VT, clinical presentations of the condition, and advanced diagnostic techniques, including electrophysiological studies and mapping. Furthermore, the review outlines the various management strategies, such as implantable cardioverter-defibrillators, catheter ablation, stereotactic arrhythmia radioablation, and surgical ablation. The discussion also includes emerging therapeutics, such as gene therapy, artificial intelligence, and precision medicine in managing scar-related VT, emphasizing the ongoing advancements aimed at improving patient outcomes.

Immunomodulatory Biomaterials: Tailoring Surface Properties to Mitigate Foreign Body Reaction and Enhance Tissue Regeneration

The immune cells have demonstrated the ability to promote tissue repair by removing debris, breaking down the extracellular matrix, and regulating cytokine secretion profile. If the behavior of immune cells is not well directed, chronic inflammation and foreign body reaction (FBR) will lead to scar formation and loss of biomaterial functionality. The immunologic response toward tissue repair or chronic inflammation after injury and implantation can be modulated by manipulating the surface properties of biomaterials. Tailoring surface properties of biomaterials enables the regulation of immune cell fate such as adhesion, proliferation, recruitment, polarization, and cytokine secretion profile. This review begins with an overview of the role of immune cells in tissue healing and their interactions with biomaterials. It then discusses how the surface properties of biomaterials influence immune cell behavior. The core focus is reviewing surface modification methods to create innovative materials that reduce foreign body reactions and enhance tissue repair and regeneration by modulating immune cell activities. The review concludes with insights into future advancements in surface modification techniques and the associated challenges.

The mechanism and promising therapeutic strategy of diabetic cardiomyopathy dysfunctions: Focus on pyroptosis

Diabetes is a major risk factor for cardiovascular diseases, and myocardial damage caused by hyperglycemia is the main cause of heart failure. However, there is still a lack of systematic understanding of myocardial damage caused by diabetes. At present, we believe that the cellular inflammatory damage caused by hyperglycemia is one of the causes of diabetic cardiomyopathy. Pyroptosis, as a proinflammatory form of cell death, is closely related to the occurrence and development of diabetic cardiomyopathy. Therefore, this paper focuses on the important role of inflammation in the occurrence and development of diabetic cardiomyopathy. From the perspective of pyroptosis, we summarize the pyroptosis of different types of cells in diabetic cardiomyopathy and its related signaling pathways. It also summarizes the treatment of diabetic cardiomyopathy, hoping to provide methods for the prevention and treatment of diabetic cardiomyopathy by inhibiting pyroptosis.

Research Advancements in the Interplay between T3 and Macrophages

3,3',5-Triiodo-L-thyronine (T3) is a key endocrine hormone in the human body that plays crucial roles in growth, development, metabolism, and immune function. Macrophages, the key regulatory cells within the immune system, exhibit marked "heterogeneity" and "plasticity", with their phenotype and function subject to modulation by local environmental signals. The interplay between the endocrine and immune systems is well documented. Numerous studies have shown that T3 significantly target macrophages, highlighting them as key cellular components in this interaction. Through the regulation of macrophage function and phenotype, T3 influences immune function and tissue repair in the body. This review comprehensively summarizes the regulatory actions and mechanisms of T3 on macrophages, offering valuable insights into further research of the immunoregulatory effects of T3.

Cardiac macrophages in maintaining heart homeostasis and regulating ventricular remodeling of heart diseases

Macrophages are most important immune cell population in the heart. Cardiac macrophages have broad-spectrum and heterogeneity, with two extreme polarization phenotypes: M1 pro-inflammatory macrophages (CCR2-ly6Chi) and M2 anti-inflammatory macrophages (CCR2-ly6Clo). Cardiac macrophages can reshape their polarization states or phenotypes to adapt to their surrounding microenvironment by altering metabolic reprogramming. The phenotypes and polarization states of cardiac macrophages can be defined by specific signature markers on the cell surface, including tumor necrosis factor α, interleukin (IL)-1β, inducible nitric oxide synthase (iNOS), C-C chemokine receptor type (CCR)2, IL-4 and arginase (Arg)1, among them, CCR2+/- is one of most important markers which is used to distinguish between resident and non-resident cardiac macrophage as well as macrophage polarization states. Dedicated balance between M1 and M2 cardiac macrophages are crucial for maintaining heart development and cardiac functional and electric homeostasis, and imbalance between macrophage phenotypes may result in heart ventricular remodeling and various heart diseases. The therapy aiming at specific target on macrophage phenotype is a promising strategy for treatment of heart diseases. In this article, we comprehensively review cardiac macrophage phenotype, metabolic reprogramming, and their role in maintaining heart health and mediating ventricular remodeling and potential therapeutic strategy in heart diseases.