Role of T-cells in myocardial infarction

Recent advances in biomimetic nanodelivery systems for the treatment of myocardial ischemia reperfusion injury

Myocardial ischemia/reperfusion injury (MIRI) is a significant challenge in the treatment of myocardial infarction, a leading cause of global mortality due to irreversible cardiac damage. Biomimetic nanodelivery systems offer promising therapeutic strategies to address MIRI. In this review, we comprehensively investigate the underlying pathophysiological mechanisms of MIRI and discuss recent advances in biomimetic nanodelivery systems including cell membrane-coated nanoparticles, exosomes, and nanoenzymes as innovative approaches for MIRI treatment. We emphasize the advantages and potential of biomimetic strategies in enhancing therapeutic efficacy, assess the preclinical effectiveness of these nanodelivery systems, and discuss the challenges associated with translating these approaches into clinical practice. This paper aims to provide new perspectives on biomimetic strategies for MIRI treatment, contributing to the development of effective drug delivery systems.

Anti-inflammatory Therapies for Ischemic Heart Disease

PURPOSE OF REVIEW

The inclusion of immunomodulatory strategies as supportive therapies in ischemic heart disease (IHD) has garnered significant support over recent years. Several such approaches appear to be unified through their ultimate target, the NLRP3 inflammasome. This review presents a brief update on immunomodulatory strategies in the continuum of conditions constituting ischemic heart disease and emphasising on the seemingly unifying mechanism of NLRP3 activation as well as modulation across these conditions.

RECENT FINDINGS

The NLRP3 inflammasome is a multiprotein complex assembled upon inflammatory stimulation, causing the release of pro-inflammatory cytokines and initiating pyroptosis. The NLRP3 pathway is relevant in inflammatory signalling of cardiac immune cells as well as non-immune cells in the myocardium, including cardiomyocytes, fibroblasts and endothelial cells. In addition to a focus on clinical outcome and efficacy trials of targeting NLRP3-related pathways, the potential connection between immunomodulation in cardiology and the NLRP3 pathway is currently being explored in preclinical trials. Colchicine, cytokine-based approaches and SGLT2 inhibitors have emerged as promising agents. However, the conditions comprising IHD including atherosclerosis, coronary artery disease (CAD), myocardial infarction (MI) and ischemic cardiomyopathy/heart failure (iCMP/HF) are not equally amenable to immunomodulation with the respective drugs. Atherosclerosis, coronary artery disease and ischemic cardiomyopathy are affected by chronic inflammation, but the immunomodulatory approach to acute inflammation in the post-MI setting remains a pharmacological challenge, as detrimental and regenerative effects of myocardial inflammation are initiated in unison. The NLRP3 inflammasome lies at the center of cell mediated inflammation in IHD. Recent trial evidence has highlighted anti-inflammatory effects of colchicine, interleukin-based therapy as well as SGLT2i in IHD and that the respective drugs modulate the NLRP3 inflammasome.

Prognosis modelling of adverse events for post-PCI treated AMI patients based on inflammation and nutrition indexes

OBJECTIVE

This study aimed to evaluate the predictive performance of inflammatory and nutritional indices for adverse cardiovascular events (ACE) in patients with acute myocardial infarction (AMI) after percutaneous coronary intervention (PCI) using a machine learning (ML) algorithm.

METHODS

AMI patients who underwent PCI were recruited and randomly divided into non/ACE groups. Inflammatory and nutritional indices were graded according to the laboratory examination reports. Logistic Regression was used to screen for factors that were significant for ML model establishment. The performances of the algorithms were evaluated in terms of accuracy, kappa, F1, receiver operating characteristic, precision recall curve, etc. RESULTS: Age, LVEF%, Killip Grade, heart rate, creatinine, albumin, neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), and prognostic nutritional index (PNI) were significantly correlated with ACE by Logistic regression analysis (P < 0.05). These nine factors were employed to establish stepwise regression (SR), random forest (RF), naïve Bayes (NB), decision trees (DT), and artificial neutron network (ANN), whose performances were evaluated in terms of accuracy, kappa, F1, receiver operating characteristic, precision recall curve, etc. The accuracy of the decision tree was greater than that of other trees. The area under the curves was the highest in the ANN model compared with the other models.

CONCLUSION

ANN predictive performance had an advantage over other ML algorithms based on age, LVEF%, Killip Grade, heart rate, creatinine, albumin, NLR, PLR, and PNI.

T cells in cardiac health and disease

Cardiovascular disease (CVD) remains the leading cause of morbidity and mortality worldwide, with inflammation playing a pivotal role in its pathogenesis. T lymphocytes are crucial components of the adaptive immune system that have emerged as key mediators in both cardiac health and the development and progression of CVD. This Review explores the diverse roles of T cell subsets, including Th1, Th17, γδ T cells, and Tregs, in myocardial inflammatory processes such as autoimmune myocarditis and myocardial infarction. We discuss the contribution of T cells to myocardial injury and remodeling, with emphasis on specific immune receptors, e.g., CD69, that have a critical role in regulating immune tolerance and maintaining the balance between T cell subsets in the heart. Additionally, we offer a perspective on recent advances in T cell-targeted therapies and their potential to modulate immune responses and improve clinical outcomes in patients with CVD and in heart transplant recipients. Understanding the intricate interplay between T cells and cardiovascular pathology is essential for developing novel immunotherapeutic strategies against CVD.

Inflammation in the Peri-ACS Period: Ready for Prime Time?

PURPOSE

Inflammation has been demonstrated to negatively impact patients in the peri-ACS period. This narrative review outlines the inflammatory response in ACS, highlighting the role of the NLRP3 inflammasome pathway following acute plaque rupture and coronary intervention and its potential as a pharmacologic target. RECENT: nvestigators have leveraged medications targeting the NLRP3 inflammasome currently used for other inflammatory pathologies, including colchicine, tocilizumab and anakinra. Investigation into these drugs in the peri-ACS period has yielded varying results, with the most encouraging findings in ACS patients treated with tocilizumab. More conflicting data exists for the role of colchicine and anakinra, with many studies limited in their power to detect clinical outcomes and heterogeneity in their patient populations and endpoints. Despite conflicting data, the NLRP3 remains an attractive therapeutic target in the peri-ACS period. Further investigation is required to prove benefit and safety with large clinical trials adequately powered for clinical outcomes.

Association of innate versus specific immunity with heart failure incidence: a prospective study

BACKGROUND

Immune disorders are key heart failure (HF) triggers, but little is known about whether the status of immunity affects the incidence of HF. To explore this, we used blood cell counts and derived ratios to investigate the association between immunity status markers and HF incidence.

METHODS

The number and proportion of peripheral blood leucocytes in a physiological state are related to the body's immune status. Neutrophils, monocytes, SII (systemic immune-inflammatory index), NLR (neutrophil-to-lymphocyte ratio), and PLR (platelet-to-lymphocyte ratio) serve as innate immunity status markers, while lymphocytes and LMR (lymphocyte-to-monocyte ratio) serve as specific immunity status markers. 330 362 UK Biobank (UKB) participants were finally examined. Cox proportional hazard models were used to explore the relationship between immunity status markers and HF incidence. Flexible parametric survival models were used to capture time-varying relationships between blood cell ratios and HRs for HF. Subgroup analyses were conducted by age, sex, and body mass index. Finally, sensitivity analyses were performed to validate the results.

RESULTS

During a median follow-up of 14.1 years, 9611 (2.9%) participants developed HF. Neutrophils, monocytes, SII, and NLR were positively associated with HF incidence, with fully adjusted per SD increment HR (95% CI) of 1.20 (1.17 to 1.22), 1.09 (1.07 to 1.12), 1.12 (1.10 to 1.14), and 1.16 (1.14 to 1.18), respectively. Platelets, lymphocytes, and LMR were inversely correlated with HF incidence, with fully adjusted per SD increment HR (95% CI) of 0.97 (0.95 to 1.00), 0.97 (0.95 to 0.99), and 0.90 (0.88 to 0.92), respectively.

CONCLUSIONS

The innate immunity status markers were positively associated with HF incidence, while specific immunity status markers exhibited an inverse association, offering novel insights for HF prediction and intervention.

A potential coagulation-related diagnostic model associated with immune infiltration for acute myocardial infarction

The production of pro-coagulation factors can affect the development and prognosis of acute myocardial infarction (AMI). The clinical value of coagulation-related genes (CRGs) was investigated to discover new targets for diagnosing and treating AMI. We screened 335 differentially expressed genes (DEGs) between AMI and healthy individuals based on the GSE66360 dataset. We took the intersection of the obtained DEGs with 139 CRGs. Finally, 10 differentially expressed CEGs were screened out. The random forest algorithm was constructed to identify 6 signature CRGs (THBS1, SERPINA1, THBD, MMP9, MAFF, and PLAU). Subsequently, the established predictive model was found to have good diagnostic accuracy (AUC = 0.9694 in the training cohort [GSE66360 dataset] and 0.9076 in the external validation cohort [GSE48060 dataset]). Consensus clustering identified the CRG clusters, and the accuracy of the grouping was verified. We found that AMI patients can be divided into two distinct subgroups based on the differentially expressed CRGs. Immune cell infiltration level was consistent with the expression levels of CRGs based on single sample gene set enrichment analysis. These findings reveal the potential role of CRGs in AMI. Characterizing the coagulation features of AMI patients can help in the risk stratification of patients and provide personalized treatment strategies.

From exosomes to mitochondria and myocardial infarction: Molecular insight and therapeutic challenge

Myocardial infarction (MI) remains a leading cause of mortality worldwide. Despite patients with MI benefit from timely reperfusion therapies, the rates of mortality and morbidity remain substantial, suggesting an enduring need for the development of new approaches. Molecular mechanisms underlying myocardial ischemic injury are associated with both cardiomyocytes and non-cardiomyocytes. Exosomes are nano-sized extracellular vesicles released by almost all eukaryotic cells. They facilitate the communication between various cells by transferring information via their cargo and altering different biological activities in recipient cells. Studies have created great prospects for therapeutic applications of exosomes in MI, as demonstrated through their beneficial effect on heart function and reducing ventricular remodeling in association with fibrosis, angiogenesis, apoptosis, and inflammation. Of note, myocardial ischemic injury is primarily due to restricted blood flow, reducing oxygen availability, and causing inefficient utilization of energy substrates. However, the impact of exosomes on cardiac energy metabolism has not been adequately investigated. Although exosomes have been engineered for targeted delivery to enhance clinical efficacy, challenges must be overcome to utilize them reliably in the clinic. In this review, we summarize the research progress of exosomes for MI with a focus on the known and unknown regarding the role of exosomes in energy metabolism in cardiomyocytes and non-cardiomyocytes; as well as potential research avenues of exosome-mitochondrial energy regulation as well as therapeutic challenges. We aim to help identify more efficient molecular targets that may promote the clinical application of exosomes.

Novel Impact of Colchicine on Interleukin-10 Expression in Acute Myocardial Infarction: An Integrative Approach

Background: Inflammation plays a critical role in myocardial infarction as a critical process in the development of heart failure, involving the development of cardiac fibrosis. Colchicine is a well-established anti-inflammatory drug, but its scientific application in controlling post-acute myocardial infarction (AMI) inflammatory processes has not been established. IL-10 is a key cytokine in modulating inflammatory responses, underscoring its potential as a crucial therapeutic target of colchicine. The objective was to explore the protective role of IL-10 modulated by colchicine in myocardial healing and repair following AMI, particularly cardiac fibrosis. Methods: The predicted protein of colchicine was assessed using WAY2DRUG PASS as probability active value. Proteins associated with colchicine, cardiac fibrosis, and acute myocardial infarction were analyzed with DisGeNET and Open Target databases. Analysis and visualization of protein-protein interactions were conducted using STRING and Cytoscape. A 3T3 cell line treated with CoCl2 was used to mimic hypoxic. HIF-1α and IL-10 expression were measured by flow cytometry and analyzed using a one-way ANOVA test. This observational clinical trial examined acute myocardial infarction patients undergoing immediate and delayed primary percutaneous coronary interventions. Subjects were randomized into control groups receiving placebo and intervention groups treated with colchicine. Assessments occurred at 24 h and five days after the intervention. IL-10 expression in the clinical trial was measured by ELISA and analyzed using a T-test. Results: Colchicine demonstrates promising bioactivity in treating acute myocardial infarction, with notably activity values highlighting its probable role as a tubulin antagonist (0.744), beta-tubulin antagonist (0.673), and NOS2 inhibitor (0.529). Its primary action targets IL-10, with the protein-protein interactions analysis indicating interactions between IL-10 and key inflammatory mediators-IL-1β, IFN-γ, CCL2, TNF, and TGF-β1-during acute myocardial infarction and cardiac fibrosis. Hypoxic conditions in the CoCl2-induced 3T3 cell model show significantly elevated HIF-1α compared to controls (p < 0.0001). Colchicine use significantly increased IL-10 expression in CoCl2-treated cells (p < 0.0001) and in AMI patients within five days (p < 0.05). Conclusions: Colchicine may bolster the anti-inflammatory response post-myocardial infarction by activating IL-10 pathways in fibroblasts and in clinical settings, potentially reducing inflammation after AMI. Further investigation into broader aspects of this pathway, particularly in cardiac fibroblasts, is required.

Identification of mitochondria-related gene biomarkers associated with immune infiltration in acute myocardial infarction

Mitochondrial dysfunction has been known to contribute to the worsening of acute myocardial infarction (AMI). We screened differentially expressed genes (DEGs) between AMI and healthy individuals based on the GSE66360 dataset. We took the intersection of the obtained DEGs with 1,136 mitochondria-related genes. Finally, we screened out mitochondria-related DEGs (MitoDEGs). Eight MitoDEGs were identified as hub genes based on the random forest algorithm. Two mitochondria-related robust molecular clusters were identified by consensus clustering. Immune infiltration analysis showed that immune cell infiltration was significantly increased in the high-expression group of MitoDEGs. We obtained the potential drugs targeted at ALDH2, PMAIP1, and BCL2A1, such as disulfiram, obatoclax mesylate, and bortezomib. Quantitative reverse-transcription polymerase chain reaction further validated the expression of the MitoDEGs in the cell model of AMI. These findings reveal the potential role of MitoDEGs in AMI and provide new insights into risk stratification and individualized treatment of AMI patients.

Systems biology-based analysis exploring shared biomarkers and pathogenesis of myocardial infarction combined with osteoarthritis

Background

More and more evidence supports the association between myocardial infarction (MI) and osteoarthritis (OA). The purpose of this study is to explore the shared biomarkers and pathogenesis of MI complicated with OA by systems biology.

Methods

Gene expression profiles of MI and OA were downloaded from the Gene Expression Omnibus (GEO) database. The Weighted Gene Co-Expression Network Analysis (WGCNA) and differentially expressed genes (DEGs) analysis were used to identify the common DEGs. The shared genes related to diseases were screened by three public databases, and the protein-protein interaction (PPI) network was built. GO and KEGG enrichment analyses were performed on the two parts of the genes respectively. The hub genes were intersected and verified by Least absolute shrinkage and selection operator (LASSO) analysis, receiver operating characteristic (ROC) curves, and single-cell RNA sequencing analysis. Finally, the hub genes differentially expressed in primary cardiomyocytes and chondrocytes were verified by RT-qPCR. The immune cell infiltration analysis, subtypes analysis, and transcription factors (TFs) prediction were carried out.

Results

In this study, 23 common DEGs were obtained by WGCNA and DEGs analysis. In addition, 199 common genes were acquired from three public databases by PPI. Inflammation and immunity may be the common pathogenic mechanisms, and the MAPK signaling pathway may play a key role in both disorders. DUSP1, FOS, and THBS1 were identified as shared biomarkers, which is entirely consistent with the results of single-cell RNA sequencing analysis, and furher confirmed by RT-qPCR. Immune infiltration analysis illustrated that many types of immune cells were closely associated with MI and OA. Two potential subtypes were identified in both datasets. Furthermore, FOXC1 may be the crucial TF, and the relationship of TFs-hub genes-immune cells was visualized by the Sankey diagram, which could help discover the pathogenesis between MI and OA.

Conclusion

In summary, this study first revealed 3 (DUSP1, FOS, and THBS1) novel shared biomarkers and signaling pathways underlying both MI and OA. Additionally, immune cells and key TFs related to 3 hub genes were examined to further clarify the regulation mechanism. Our study provides new insights into shared molecular mechanisms between MI and OA.

The Influence of Metabolic Risk Factors on the Inflammatory Response Triggered by Myocardial Infarction: Bridging Pathophysiology to Treatment

Myocardial infarction (MI) sets off a complex inflammatory cascade that is crucial for effective cardiac healing and scar formation. Yet, if this response becomes excessive or uncontrolled, it can lead to cardiovascular complications. This review aims to provide a comprehensive overview of the tightly regulated local inflammatory response triggered in the early post-MI phase involving cardiomyocytes, (myo)fibroblasts, endothelial cells, and infiltrating immune cells. Next, we explore how the bone marrow and extramedullary hematopoiesis (such as in the spleen) contribute to sustaining immune cell supply at a cardiac level. Lastly, we discuss recent findings on how metabolic cardiovascular risk factors, including hypercholesterolemia, hypertriglyceridemia, diabetes, and hypertension, disrupt this immunological response and explore the potential modulatory effects of lifestyle habits and pharmacological interventions. Understanding how different metabolic risk factors influence the inflammatory response triggered by MI and unraveling the underlying molecular and cellular mechanisms may pave the way for developing personalized therapeutic approaches based on the patient's metabolic profile. Similarly, delving deeper into the impact of lifestyle modifications on the inflammatory response post-MI is crucial. These insights may enable the adoption of more effective strategies to manage post-MI inflammation and improve cardiovascular health outcomes in a holistic manner.

The roles of Th cells in myocardial infarction

Myocardial infarction, commonly known as a heart attack, is a serious condition caused by the abrupt stoppage of blood flow to a part of the heart, leading to tissue damage. A significant aspect of this condition is reperfusion injury, which occurs when blood flow is restored but exacerbates the damage. This review first addresses the role of the innate immune system, including neutrophils and macrophages, in the cascade of events leading to myocardial infarction and reperfusion injury. It then shifts focus to the critical involvement of CD4+ T helper cells in these processes. These cells, pivotal in regulating the immune response and tissue recovery, include various subpopulations such as Th1, Th2, Th9, Th17, and Th22, each playing a unique role in the pathophysiology of myocardial infarction and reperfusion injury. These subpopulations contribute to the injury process through diverse mechanisms, with cytokines such as IFN-γ and IL-4 influencing the balance between tissue repair and injury exacerbation. Understanding the interplay between the innate immune system and CD4+ T helper cells, along with their cytokines, is crucial for developing targeted therapies to mitigate myocardial infarction and reperfusion injury, ultimately improving outcomes for cardiac patients.

Immunometabolism in atherosclerotic disorders

Cardiovascular diseases (CVDs), including atherosclerosis, myocardial infarction and heart failure, are the leading causes of morbidity and mortality worldwide. Emerging evidence suggests a crucial role for immune cell dysfunction and inflammation in the progression of this complex set of diseases. Recent advances demonstrate that immune cells, tightly linked to CVD pathogenesis, are sensitive to environmental signals and respond by engaging immunometabolic networks that shape their behavior. Inflammatory cues and altered nutrient availability within atherosclerotic plaques or following ischemia synergize to elicit metabolic shifts in immune cells that influence the course of disease pathology. Understanding these metabolic adaptations and how they contribute to cellular dysfunction may reveal novel therapeutic approaches for the treatment of CVD. Here we provide a comprehensive summary of the metabolic reprogramming that occurs in immune cells and their progenitors during CVD, offering insights into the potential therapeutic interventions to mitigate disease progression.

Antigen presentation plays positive roles in the regenerative response to cardiac injury in zebrafish

In contrast to adult mammals, adult zebrafish can fully regenerate injured cardiac tissue, and this regeneration process requires an adequate and tightly controlled immune response. However, which components of the immune response are required during regeneration is unclear. Here, we report positive roles for the antigen presentation-adaptive immunity axis during zebrafish cardiac regeneration. We find that following the initial innate immune response, activated endocardial cells (EdCs), as well as immune cells, start expressing antigen presentation genes. We also observe that T helper cells, a.k.a. Cd4+ T cells, lie in close physical proximity to these antigen-presenting EdCs. We targeted Major Histocompatibility Complex (MHC) class II antigen presentation by generating cd74a; cd74b mutants, which display a defective immune response. In these mutants, Cd4+ T cells and activated EdCs fail to efficiently populate the injured tissue and EdC proliferation is significantly decreased. cd74a; cd74b mutants exhibit additional defects in cardiac regeneration including reduced cardiomyocyte dedifferentiation and proliferation. Notably, Cd74 also becomes activated in neonatal mouse EdCs following cardiac injury. Altogether, these findings point to positive roles for antigen presentation during cardiac regeneration, potentially involving interactions between activated EdCs, classical antigen-presenting cells, and Cd4+ T cells.

Blood Cell Ratios Unveiled: Predictive Markers of Myocardial Infarction Prognosis

BACKGROUND

Even if the management and treatment of patients with non-ST-elevation myocardial infarction (NSTEMI) have significantly evolved, it is still a burgeoning disease, an active volcano with very high rates of morbidity and mortality. Therefore, novel management and therapeutic strategies for this condition are urgently needed. Lately, theories related to the role of various blood cells in NSTEMI have emerged, with most of this research having so far been focused on correlating the ratios between various leukocyte types (neutrophil/lymphocyte ratio-NLR, neutrophil/monocyte ratio-NMR). But what about erythrocytes? Is there an interaction between these cells and leukocytes, and furthermore, can this relationship influence NSTEMI prognosis? Are they partners in crime?

METHODS

Through the present study, we sought, over a period of sixteen months, to evaluate the neutrophil/red blood cell ratio (NRR), monocyte/red blood cell ratio (MRR) and lymphocyte/red blood cell ratio (LRR), assessing their potential role as novel prognostic markers in patients with NSTEMI.

RESULTS

There was a statistically significant correlation between the NRR, LRR, MRR and the prognosis of NSTEMI patients.

CONCLUSIONS

These new predictive markers could represent the start of future innovative therapies that may influence crosstalk pathways and have greater benefits in terms of cardiac repair and the secondary prevention of NSTEMI.

Anti-inflammatory and immunoregulatory effects of colistin sulphate on human PBMCs

In previous studies, CST has been identified as having an immunostimulatory effect on Caenorhabditis elegans and macrophage of rats. Here, we further investigated its immunomodulatory effects on human peripheral blood mononuclear cells (PBMCs). LPS-stimulated PBMCs inflammatory model was established. Flow cytometry was applied to measure phagocytosis of PBMCs. Cytokine mRNA and protein expression levels of LPS-stimulated PBMCs with or without CST were measured by qRT-PCR and ELISA. The transcriptomic profile of CST-treated PBMCs was investigated by RNA-sequencing. Gene Ontology (GO) and Kyoto Encylopedia of Genes and Genomes (KEGG) were applied to find potential signalling pathways. PBMCs showed a significant increase in phagocytic activity at 6 h after being incubated with CST at the concentration of 10 μg/mL. In the presence of LPS, CST maintained and promoted the expression of TNF-α and chemokine CCL24. The content of pro-inflammatory cytokines, such as IL-1β, IL-6 and IFN-γ, which were released from LPS-stimulated PBMCs, was reduced by CST at 6 h. Anti-inflammatory cytokines, such as IL-4, IL-13 and TGF-β1, were significantly increased by CST at 24 h. A total of 277 differentially expressed immune-related genes (DEIRGs) were detected and cytokine-cytokine receptor interaction was highly enriched. CST presented obvious anti-inflammatory and immunoregulatory effects in LPS-induced PBMCs inflammatory model not only by improving the ability of PBMCs to clear pathogens but also by decreasing pro-inflammatory cytokines and increasing anti-inflammatory cytokines. And the mechanism may be related to cytokine-cytokine receptor interaction.

Fibroblasts and platelets: a face-to-face dialogue at the heart of cardiac fibrosis

Myocardial fibrosis is a feature found in most cardiac diseases and a key element contributing to heart failure and its progression. It has therefore become a subject of particular interest in cardiac research. Mechanisms leading to pathological cardiac remodeling and heart failure are diverse, including effects on cardiac fibroblasts, the main players in cardiac extracellular matrix synthesis, but also on cardiomyocytes, immune cells, endothelial cells, and more recently, platelets. Although transforming growth factor-β (TGF-β) is a primary regulator of fibrosis development, the cellular and molecular mechanisms that trigger its activation after cardiac injury remain poorly understood. Different types of anti-TGF-β drugs have been tested for the treatment of cardiac fibrosis and have been associated with side effects. Therefore, a better understanding of these mechanisms is of great clinical relevance and could allow us to identify new therapeutic targets. Interestingly, it has been shown that platelets infiltrate the myocardium at an early stage after cardiac injury, producing large amounts of cytokines and growth factors. These molecules can directly or indirectly regulate cells involved in the fibrotic response, including cardiac fibroblasts and immune cells. In particular, platelets are known to be a major source of TGF-β1. In this review, we have provided an overview of the classical cellular effectors involved in the pathogenesis of cardiac fibrosis, focusing on the emergent role of platelets, while discussing opportunities for novel therapeutic interventions.

Inflammation in acute myocardial infarction: the good, the bad and the ugly

Convergent experimental and clinical evidence have established the pathophysiological importance of pro-inflammatory pathways in coronary artery disease. Notably, the interest in treating inflammation in patients suffering acute myocardial infarction (AMI) is now expanding from its chronic aspects to the acute setting. Few large outcome trials have proven the benefits of anti-inflammatory therapies on cardiovascular outcomes by targeting the residual inflammatory risk (RIR), i.e. the smouldering ember of low-grade inflammation persisting in the late phase after AMI. However, these studies have also taught us about potential risks of anti-inflammatory therapy after AMI, particularly related to impaired host defence. Recently, numerous smaller-scale trials have addressed the concept of targeting a deleterious flare of excessive inflammation in the early phase after AMI. Targeting different pathways and implementing various treatment regimens, those trials have met with varied degrees of success. Promising results have come from those studies intervening early on the interleukin-1 and -6 pathways. Taking lessons from such past research may inform an optimized approach to target post-AMI inflammation, tailored to spare 'The Good' (repair and defence) while treating 'The Bad' (smouldering RIR) and capturing 'The Ugly' (flaming early burst of excess inflammation in the acute phase). Key constituents of such a strategy may read as follows: select patients with large pro-inflammatory burden (i.e. large AMI); initiate treatment early (e.g. ≤12 h post-AMI); implement a precisely targeted anti-inflammatory agent; follow through with a tapering treatment regimen. This approach warrants testing in rigorous clinical trials.

PD-L1 and AKT Overexpressing Adipose-Derived Mesenchymal Stem Cells Enhance Myocardial Protection by Upregulating CD25+ T Cells in Acute Myocardial Infarction Rat Model

This study explores the synergistic impact of Programmed Death Ligand 1 (PD-L1) and Protein Kinase B (Akt) overexpression in adipose-derived mesenchymal stem cells (AdMSCs) for ameliorating cardiac dysfunction after myocardial infarction (MI). Post-MI adult Wistar rats were allocated into four groups: sham, MI, ADMSC treatment, and ADMSCs overexpressed with PD-L1 and Akt (AdMSC-PDL1-Akt) treatment. MI was induced via left anterior descending coronary artery ligation, followed by intramyocardial AdMSC injections. Over four weeks, cardiac functionality and structural integrity were assessed using pressure-volume analysis, infarct size measurement, and immunohistochemistry. AdMSC-PDL1-Akt exhibited enhanced resistance to reactive oxygen species (ROS) in vitro and ameliorated MI-induced contractile dysfunction in vivo by improving the end-systolic pressure-volume relationship and preload-recruitable stroke work, together with attenuating infarct size. Molecular analyses revealed substantial mitigation in caspase3 and nuclear factor-κB upregulation in MI hearts within the AdMSC-PDL1-Akt group. Mechanistically, AdMSC-PDL1-Akt fostered the differentiation of normal T cells into CD25+ regulatory T cells in vitro, aligning with in vivo upregulation of CD25 in AdMSC-PDL1-Akt-treated rats. Collectively, PD-L1 and Akt overexpression in AdMSCs bolsters resistance to ROS-mediated apoptosis in vitro and enhances myocardial protective efficacy against MI-induced dysfunction, potentially via T-cell modulation, underscoring a promising therapeutic strategy for myocardial ischemic injuries.

Protective effect of canagliflozin on post-resuscitation myocardial function in a rat model of cardiac arrest

BACKGROUND

Currently, most patients with cardiac arrest (CA) show reversible myocardial dysfunction, hemodynamic instability, systemic inflammation and other pathophysiological state in early stage of resuscitation, some patients may eventually progress to multiple organ failure. There is evidence that heart failure is the terminal stage in the development of various cardiovascular diseases. Although the cardio-protective effect of canagliflozin (CANA) has been confirmed in large clinical studies and recommended in domestic and international heart failure-related guidelines, the effectiveness of CANA after resuscitation remains unclear. In this study, we constructed a modified CA/CPR rat model to investigate whether CANA administered on post-resuscitation improves myocardial function.

METHODS

Twenty-fourth healthy male Sprague-Dawley rats were randomized into four groups: (1) Sham + placebo group, (2) Sham + CANA group, (3) CPR + placebo group, and (4) CPR + CANA group. Ventricular fibrillation was induced by transcutaneous electrical stimulation on epicardium. After 6 min untreated ventricular fibrillation, chest compressions was initiated. The rats were received an injection of placebo or canagliflozin (3 ug/kg) randomly 15 min after restore of spontaneous circulation (ROSC). Electrocardiogram (ECG) and blood pressure were continuously detected in each group throughout the experiment. The rats were killed 6 h after ROSC to collected the arterial serum and myocardial tissue. Myocardial injury was estimated with concentrations of inflammatory factors, oxidative stress indexes and, apoptosis index, myocardial injury markers, echocardiography and myocardial pathological slices.

RESULTS

After resuscitation, mean arterial pressure (MAP) were significantly increased after cardiopulmonary resuscitation in CANA group rats when compared with placebo group. Heart rate, body lactate returned and left ventricular ejection fraction (LVEF) to normal levels in a shorter time and the myocardial injury was obviously attenuated in CPR + CANA group. Inflammatory factors (IL-6, TNF-α) and oxidative stress indexes (MAD, SOD, CAT) were dramatically decreased with the administration of CANA. The expression of apoptosis index (BAX, caspase-3) were higher in CPR + placebo group and the expression of anti-apoptosis index (Bcl-2) was lower (P < 0.05).

CONCLUSIONS

The administration of CANA effectively reduces myocardial ischaemia/reperfusion (I/R) injury after cardiac arrest and cardiopulmonary resuscitation (CPR), and the underlying mechanism may be related to anti-inflammation, oxidative stress and apoptosis.

Human peripheral blood mononuclear cells display a temporal evolving inflammatory profile after myocardial infarction and modify myocardial fibroblasts phenotype

Pathophysiological response after acute myocardial infarction (AMI) is described as a three-stage model involving temporal phenotypic modifications of both immune cells and fibroblasts: a primary inflammatory phase, followed by a reparative phase and a fibrous scar maturation phase. Purinergic receptors, particularly the P2Y11 receptor, have been reported to be involved in the regulation of inflammation after ischemia and could act for the resolution of inflammation after AMI. For the first time, we characterized the immuno-inflammatory and P2Y11 expression profiles of peripheral blood mononuclear cells (PBMC) from AMI patients and analyzed the consequences of presenting these cells to cardiac fibroblasts in vitro. PBMC from 178 patients were collected at various times after reperfused ST-segment elevation AMI, from H0 to M12. Expression level of P2RY11 and genes involved in tolerogenic profile of dendritic cells and T cell polarization were evaluated by RT-PCR. P2Y11 protein expression was assessed by flow cytometry. PBMC and human cardiac fibroblasts (HCF) were cocultured and α-SMA/vimentin ratio was analyzed by flow cytometry. Within the first 48 h after AMI, expression levels of HMOX1, STAT3 and CD4 increased while IDO1 and TBX21/GATA3 ratio decreased. Concomitantly, the expression of P2RY11 increased in both T and B cells. In vitro, PBMC collected at H48 after AMI induced an increase in α-SMA/vimentin ratio in HCF. Our results suggest that human PBMC display an evolving inflammatory profile with reparative characteristics the first two days after AMI and secrete soluble mediators leading to the fibroblastic proteins modification, thus participating to myocardial fibrosis.

Gut-derived short-chain fatty acids bridge cardiac and systemic metabolism and immunity in heart failure

Heart failure (HF) represents a group of complex clinical syndromes with high morbidity and mortality and has a significant global health burden. Inflammation and metabolic disorders are closely related to the development of HF, which are complex and depend on the severity and type of HF and common metabolic comorbidities such as obesity and diabetes. An increasing body of evidence indicates the importance of short-chain fatty acids (SCFAs) in regulating cardiac function. In addition, SCFAs represent a unique class of metabolites and play a distinct role in shaping systemic immunity and metabolism. In this review, we reveal the role of SCFAs as a link between metabolism and immunity, which regulate cardiac and systemic immune and metabolic systems by acting as energy substrates, inhibiting the expression of histone deacetylase (HDAC) regulated genes and activating G protein-coupled receptors (GPCRs) signaling. Ultimately cardiac efficiency is improved, cardiac inflammation alleviated and cardiac function in failing hearts enhanced. In conclusion, SCFAs represent a new therapeutic approach for HF.

Transgenic Mice Expressing Functional TCRs Specific to Cardiac Myhc-α 334-352 on Both CD4 and CD8 T Cells Are Resistant to the Development of Myocarditis on C57BL/6 Genetic Background

Myocarditis is a predominant cause of congestive heart failure and sudden death in children and young adolescents that can lead to dilated cardiomyopathy. Lymphocytic myocarditis mediated by T cells can result from the recognition of cardiac antigens that may involve CD4 or CD8 T cells or both. In this report, we describe the generation of T cell receptor (TCR) transgenic mice on a C57BL/6 genetic background specific to cardiac myosin heavy chain (Myhc)-α 334-352 and make the following observations: First, we verified that Myhc-α 334-352 was immunogenic in wild-type C57BL/6 mice and induced antigen-specific CD4 T cell responses despite being a poor binder of IAb; however, the immunized animals developed only mild myocarditis. Second, TCRs specific to Myhc-α 334-352 in transgenic mice were expressed in both CD4 and CD8 T cells, suggesting that the expression of epitope-specific TCR is common to both cell types. Third, although T cells from naïve transgenic mice did not respond to Myhc-α 334-352, both CD4 and CD8 T cells from animals immunized with Myhc-α 334-352 responded to the peptide, indicating that antigen priming is necessary to break tolerance. Fourth, although the transgenic T cells could produce significant amounts of interferon-γ and interleukin-17, the immunized animals developed only mild disease, indicating that other soluble factors might be necessary for developing severe myocarditis. Alternatively, the C57BL/6 genetic background might be a major contributing factor for resistance to the development of myocarditis. Taken together, our model permits the determination of the roles of both CD4 and CD8 T cells to understand the disease-resistance mechanisms of myocarditis in a single transgenic system antigen-specifically.

Macrophages in the Inflammatory Phase following Myocardial Infarction: Role of Exogenous Ubiquitin

Cardiovascular disease (CVD) is one of the leading causes of death worldwide. One of the most common implications of CVD is myocardial infarction (MI). Following MI, the repair of the infarcted heart occurs through three distinct, yet overlapping phases of inflammation, proliferation, and maturation. Macrophages are essential to the resolution of the inflammatory phase due to their role in phagocytosis and efferocytosis. However, excessive and long-term macrophage accumulation at the area of injury and dysregulated function can induce adverse cardiac remodeling post-MI. Ubiquitin (UB) is a highly evolutionarily conserved small protein and is a normal constituent of plasma. Levels of UB are increased in the plasma during a variety of pathological conditions, including ischemic heart disease. Treatment of mice with UB associates with decreased inflammatory response and improved heart function following ischemia/reperfusion injury. This review summarizes the role of macrophages in the infarct healing process of the heart post-MI, and discusses the role of exogenous UB in myocardial remodeling post-MI and in the modulation of macrophage phenotype and function.

Cardiovascular disease biomarkers derived from circulating cell-free DNA methylation

Acute coronary syndrome (ACS) remains a major cause of worldwide mortality. The syndrome occurs when blood flow to the heart muscle is decreased or blocked, causing muscle tissues to die or malfunction. There are three main types of ACS: Non-ST-elevation myocardial infarction, ST-elevation myocardial infarction, and unstable angina. The treatment depends on the type of ACS, and this is decided by a combination of clinical findings, such as electrocardiogram and plasma biomarkers. Circulating cell-free DNA (ccfDNA) is proposed as an additional marker for ACS since the damaged tissues can release DNA to the bloodstream. We used ccfDNA methylation profiles for differentiating between the ACS types and provided computational tools to repeat similar analysis for other diseases. We leveraged cell type specificity of DNA methylation to deconvolute the ccfDNA cell types of origin and to find methylation-based biomarkers that stratify patients. We identified hundreds of methylation markers associated with ACS types and validated them in an independent cohort. Many such markers were associated with genes involved in cardiovascular conditions and inflammation. ccfDNA methylation showed promise as a non-invasive diagnostic for acute coronary events. These methods are not limited to acute events, and may be used for chronic cardiovascular diseases as well.

Endothelial Dysfunction in Patients Undergoing Cardiac Surgery: A Narrative Review and Clinical Implications

Cardiac surgery is one of the highest-risk procedures, usually involving cardiopulmonary bypass and commonly inducing endothelial injury that contributes to the development of perioperative and postoperative organ dysfunction. Substantial scientific efforts are being made to unravel the complex interaction of biomolecules involved in endothelial dysfunction to find new therapeutic targets and biomarkers and to develop therapeutic strategies to protect and restore the endothelium. This review highlights the current state-of-the-art knowledge on the structure and function of the endothelial glycocalyx and mechanisms of endothelial glycocalyx shedding in cardiac surgery. Particular emphasis is placed on potential strategies to protect and restore the endothelial glycocalyx in cardiac surgery. In addition, we have summarized and elaborated the latest evidence on conventional and potential biomarkers of endothelial dysfunction to provide a comprehensive synthesis of crucial mechanisms of endothelial dysfunction in patients undergoing cardiac surgery, and to highlight their clinical implications.

Crosstalk between macrophages and cardiac cells after myocardial infarction

Cardiovascular diseases, such as myocardial infarction (MI), are a leading cause of death worldwide. Acute MI (AMI) inflicts massive injury to the coronary microcirculation, causing large-scale cardiomyocyte death due to ischemia and hypoxia. Inflammatory cells such as monocytes and macrophages migrate to the damaged area to clear away dead cells post-MI. Macrophages are pleiotropic cells of the innate immune system, which play an essential role in the initial inflammatory response that occurs following MI, inducing subsequent damage and facilitating recovery. Besides their recognized role within the immune response, macrophages participate in crosstalk with other cells (including cardiomyocytes, fibroblasts, immune cells, and vascular endothelial cells) to coordinate post-MI processes within cardiac tissue. Macrophage-secreted exosomes have recently attracted increasing attention, which has led to a more elaborate understanding of macrophage function. Currently, the functional roles of macrophages in the microenvironment of the infarcted heart, particularly with regard to their interaction with surrounding cells, remain unclear. Understanding the specific mechanisms that mediate this crosstalk is essential in treating MI. In this review, we discuss the origin of macrophages, changes in their distribution post-MI, phenotypic and functional plasticity, as well as the specific signaling pathways involved, with a focus on the crosstalk with other cells in the heart. Thus, we provide a new perspective on the treatment of MI. Further in-depth research is required to elucidate the mechanisms underlying crosstalk between macrophages and other cells within cardiac tissue for the identification of potential therapeutic targets. Video Abstract.

CD137 signaling aggravates myocardial ischemia-reperfusion injury by inhibiting mitophagy mediated NLRP3 inflammasome activation

BACKGROUND

The inflammatory response caused by the NLRP3 is closely related to the formation of myocardial ischemia-reperfusion injury. Costimulatory receptor CD137 and its ligand play a crucial role in regulating the inflammatory immune response in atherosclerosis, which is the fundamental cause of cardiovascular diseases. However, the roles of CD137 signaling in the process of myocardial ischaemia-reperfusion (IR) injury remain unknown.

METHODS

Genetic ablation was used to determine the functional significance of CD137 in myocardial IR injury. Expression of CD137 was examined by Western-blot, quantitative real-time polymerase chain reaction, and immunohistochemistry in a murine IR model by coronary artery ligation. Even's blue-TTC staining and echocardiography to evaluate the severity of myocardial IR injury. Furthermore, HL-1 cardiomyocytes treated with agonist-CD137 recombinant protein were used to explore the underlying mechanism in CD137 signaling-induced NLRP3 inflammasome activation in response to hypoxia/reoxygenation or LPS/ATP.

RESULTS

We demonstrated that CD137 knockout significantly improved cardiac function, accompanied by a markedly reduced NLRP3-mediated inflammatory response and IA/AAR which were reversed by mitophagy inhibitor Mdivi-1. Activating CD137 signaling significantly inhibited mitophagy and provoked NLRP3-mediated inflammatory response in H/R-injured or LPS-primed and ATP-stimulated HL-1 cardiomyocytes, the effects of which could be abolished by either anti-CD137 or mitophagy activator FCCP. Besides, mitochondrial ROS was augmented by activating CD137 signaling through the suppression of mitophagy.

CONCLUSIONS

Our results reveal that activating CD137 signaling aggravates myocardial IR injury by upregulating NLRP3 inflammasome activation via suppressing mitophagy and promoting mtROS generation.

Peli1 deletion in macrophages attenuates myocardial ischemia/reperfusion injury by suppressing M1 polarization

The polarization of macrophages to the M1 or M2 phenotype has a pivotal role in inflammatory response following myocardial ischemia/reperfusion injury. Peli1, an E3 ubiquitin ligase, is closely associated with inflammation and autoimmunity as an important regulatory protein in the Toll-like receptor signaling pathway. We aimed to explore the function of Peli1 in macrophage polarization under myocardial ischemia/reperfusion injury and elucidate the possible mechanisms. We show here that Peli1 is upregulated in peripheral blood mononuclear cells from patients with myocardial ischemia/reperfusion, which is correlated with myocardial injury and cardiac dysfunction. We also found that the proportion of M1 macrophages was reduced and myocardial infarct size was decreased, paralleling improvement of cardiac function in mice with Peli1 deletion in hematopoietic cells or macrophages. Macrophage Peli1 deletion lessened M1 polarization and reduced the migratory ability in vitro. Mechanistically, Peli1 contributed to M1 polarization by promoting K63-linked ubiquitination and nuclear translocation of IRF5. Moreover, Peli1 deficiency in macrophages reduced the apoptosis of cardiomyocytes in vivo and in vitro. Together, our study demonstrates that Peli1 deficiency in macrophages suppresses macrophage M1 polarization and alleviates myocardial ischemia/reperfusion injury by inhibiting the nuclear translocation of IRF5, which may serve as a potential intervention target for myocardial ischemia/reperfusion injury.

The role of major immune cells in myocardial infarction

Myocardial infarction (MI) is a cardiovascular disease (CVD) with high morbidity and mortality worldwide, often leading to adverse cardiac remodeling and heart failure, which is a serious threat to human life and health. The immune system makes an important contribution to the maintenance of normal cardiac function. In the disease process of MI, necrotic cardiomyocytes release signals that activate nonspecific immunity and trigger the action of specific immunity. Complex immune cells play an important role in all stages of MI progression by removing necrotic cardiomyocytes and tissue and promoting the healing of damaged tissue cells. With the development of biomaterials, cardiac patches have become an emerging method of repairing MI, and the development of engineered cardiac patches through the construction of multiple animal models of MI can help treat MI. This review introduces immune cells involved in the development of MI, summarizes the commonly used animal models of MI and the newly developed cardiac patch, so as to provide scientific reference for the accurate diagnosis and effective treatment of MI.

T-Cell Mineralocorticoid Receptor Deficiency Attenuates Pathologic Ventricular Remodelling After Myocardial Infarction

BACKGROUND

Mineralocorticoid receptor (MR) antagonists have been widely used to treat heart failure (HF). Studies have shown that MR in T cells plays important roles in hypertension and myocardial hypertrophy. However, the function of T-cell MR in myocardial infarction (MI) has not been elucidated.

METHODS

In this study, we used T-cell MR knockout (TMRKO) mouse to investigate the effects of T-cell MR deficiency on MI and to explore the underlying mechanisms. Echocardiography and tissue staining were used to assess cardiac function, fibrosis, and myocardial apoptosis after MI. Flow cytometry and quantitative real-time polymerase chain reaction (qRT-PCR) were used to detect immune cell infiltration and inflammation.

RESULTS

T-cell MR deficiency significantly improved cardiac function, promoted myocardial repair, and inhibited myocardial apoptosis, fibrosis, and inflammation after MI. Luminex assays revealed that TMRKO mice had significantly lower levels of interferon-gamma (IFN-γ) and interleukin-6 (IL-6) in serum and infarcted myocardium than littermate control mice. In cultured splenic T cells, MR deficiency suppressed IL-6 expression, whereas MR overexpression enhanced IL-6 expression. Chromatin immunoprecipitation (ChIP) assay demonstrated that MR bound to the MR response element on the promoter of IL-6 gene. Finally, T-cell MR deficiency significantly suppressed accumulation of macrophages in infarcted myocardium and differentiation of proinflammatory macrophages, thereby alleviating the consequences of MI.

CONCLUSIONS

T-cell MR deficiency improved pathologic ventricular remodelling after MI, likely through inhibition of accumulation and differentiation of proinflammatory macrophages. At the molecular level, MR may work through IFN-γ and IL-6 in T cells to exert functions in MI.

Cardiac repair after myocardial infarction: A two-sided role of inflammation-mediated

Myocardial infarction is the leading cause of death and disability worldwide, and the development of new treatments can help reduce the size of myocardial infarction and prevent adverse cardiovascular events. Cardiac repair after myocardial infarction can effectively remove necrotic tissue, induce neovascularization, and ultimately replace granulation tissue. Cardiac inflammation is the primary determinant of whether beneficial cardiac repair occurs after myocardial infarction. Immune cells mediate inflammatory responses and play a dual role in injury and protection during cardiac repair. After myocardial infarction, genetic ablation or blocking of anti-inflammatory pathways is often harmful. However, enhancing endogenous anti-inflammatory pathways or blocking endogenous pro-inflammatory pathways may improve cardiac repair after myocardial infarction. A deficiency of neutrophils or monocytes does not improve overall cardiac function after myocardial infarction but worsens it and aggravates cardiac fibrosis. Several factors are critical in regulating inflammatory genes and immune cells' phenotypes, including DNA methylation, histone modifications, and non-coding RNAs. Therefore, strict control and timely suppression of the inflammatory response, finding a balance between inflammatory cells, preventing excessive tissue degradation, and avoiding infarct expansion can effectively reduce the occurrence of adverse cardiovascular events after myocardial infarction. This article reviews the involvement of neutrophils, monocytes, macrophages, and regulatory T cells in cardiac repair after myocardial infarction. After myocardial infarction, neutrophils are the first to be recruited to the damaged site to engulf necrotic cell debris and secrete chemokines that enhance monocyte recruitment. Monocytes then infiltrate the infarct site and differentiate into macrophages and they release proteases and cytokines that are harmful to surviving myocardial cells in the pre-infarct period. As time progresses, apoptotic neutrophils are cleared, the recruitment of anti-inflammatory monocyte subsets, the polarization of macrophages toward the repair phenotype, and infiltration of regulatory T cells, which secrete anti-inflammatory factors that stimulate angiogenesis and granulation tissue formation for cardiac repair. We also explored how epigenetic modifications regulate the phenotype of inflammatory genes and immune cells to promote cardiac repair after myocardial infarction. This paper also elucidates the roles of alarmin S100A8/A9, secreted frizzled-related protein 1, and podoplanin in the inflammatory response and cardiac repair after myocardial infarction.

Identification of GLS as a cuproptosis-related diagnosis gene in acute myocardial infarction

Acute myocardial infarction (AMI) has the characteristics of sudden onset, rapid progression, poor prognosis, and so on. Therefore, it is urgent to identify diagnostic and prognostic biomarkers for it. Cuproptosis is a new form of mitochondrial respiratory-dependent cell death. However, studies are limited on the clinical significance of cuproptosis-related genes (CRGs) in AMI. In this study, we systematically assessed the genetic alterations of CRGs in AMI by bioinformatics approach. The results showed that six CRGs (LIAS, LIPT1, DLAT, PDHB, MTF1, and GLS) were markedly differentially expressed between stable coronary heart disease (stable_CAD) and AMI. Correlation analysis indicated that CRGs were closely correlated with N6-methyladenosine (m6A)-related genes through R language “corrplot” package, especially GLS was positively correlated with FMR1 and MTF1 was negatively correlated with HNRNPA2B1. Immune landscape analysis results revealed that CRGs were closely related to various immune cells, especially GLS was positively correlated with T cells CD4 memory resting and negatively correlated with monocytes. Kaplan–Meier analysis demonstrated that the group with high DLAT expression had a better prognosis. The area under curve (AUC) certified that GLS had good diagnostic value, in the training set (AUC = 0.87) and verification set (ACU = 0.99). Gene set enrichment analysis (GSEA) suggested that GLS was associated with immune- and hypoxia-related pathways. In addition, Gene Ontology (GO) analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, competing endogenous RNA (ceRNA) analysis, transcription factor (TF), and compound prediction were performed to reveal the regulatory mechanism of CRGs in AMI. Overall, our study can provide additional information for understanding the role of CRGs in AMI, which may provide new insights into the identification of therapeutic targets for AMI.

Inflammation in myocardial infarction: roles of mesenchymal stem cells and their secretome

Inflammation plays crucial roles in the regulation of pathophysiological processes involved in injury, repair and remodeling of the infarcted heart; hence, it has become a promising target to improve the prognosis of myocardial infarction (MI). Mesenchymal stem cells (MSCs) serve as an effective and innovative treatment option for cardiac repair owing to their paracrine effects and immunomodulatory functions. In fact, transplanted MSCs have been shown to accumulate at injury sites of heart, exerting multiple effects including immunomodulation, regulating macrophages polarization, modulating the activation of T cells, NK cells and dendritic cells and alleviating pyroptosis of non-immune cells. Many studies also proved that preconditioning of MSCs can enhance their inflammation-regulatory effects. In this review, we provide an overview on the current understanding of the mechanisms on MSCs and their secretome regulating inflammation and immune cells after myocardial infarction and shed light on the applications of MSCs in the treatment of cardiac infarction.

A coalition to heal-the impact of the cardiac microenvironment

Heart regenerative medicine has been gradually evolving from a view of the heart as a nonregenerative organ with terminally differentiated cardiac muscle cells. Understanding the biology of the heart during homeostasis and in response to injuries has led to the realization that cellular communication between all cardiac cell types holds great promise for treatments. Indeed, recent studies highlight new disease-reversion concepts in addition to cardiomyocyte renewal, such as matrix- and vascular-targeted therapies, and immunotherapy with a focus on inflammation and fibrosis. In this review, we will discuss the cross-talk within the cardiac microenvironment and how specific therapies aim to target the hostile cardiac milieu under pathological conditions.

Hyaluronan Synthase 3 is Protective After Cardiac Ischemia-Reperfusion by preserving the T cell Response

Dysregulated extracellular matrix (ECM) is a hallmark of adverse cardiac remodeling after myocardial infarction (MI). Previous work from our laboratory suggests that synthesis of the major ECM component hyaluronan (HA) may be beneficial for post-infarct healing. Here, we aimed to investigate the mechanisms of hyaluronan synthase 3 (HAS3) in cardiac healing after MI. Mice with genetic deletion of Has3 (Has3 KO) and wildtype mice (WT) underwent 45 minutes of ischemia with subsequent reperfusion (I/R), followed by monitoring of heart function and analysis of tissue remodeling for up to three weeks. Has3 KO mice exhibited impaired cardiac function as evidenced by a reduced ejection fraction. Accordingly, Has3 deficiency also resulted in an increased scar size. Cardiac fibroblast activation and CD68⁺ macrophage counts were similar between genotypes. However, we found a significant decrease in CD4 T cells in the hearts of Has3 KO mice seven days post-MI, in particular reduced numbers of CD4⁺CXCR3⁺ Th1 and CD4⁺CD25⁺ Treg cells. Furthermore, Has3 deficient cardiac T cells were less activated and more apoptotic as shown by decreased CD69⁺ and increased annexin V⁺ cells, respectively. In vitro assays using activated splenic CD3 T cells demonstrated that Has3 deficiency resulted in reduced expression of the main HA receptor CD44 and diminished T cell proliferation. T cell transendothelial migration was similar between genotypes. Of note, analysis of peripheral blood from patients with ST-elevation myocardial infarction (STEMI) revealed that HAS3 is the predominant HAS isoenzyme also in human T cells. In conclusion, our data suggest that HAS3 is required for mounting a physiological T cell response after MI to support cardiac healing. Therefore, our study may serve as a foundation for the development of novel strategies targeting HA-matrix to preserve T cell function after MI.

The mechanistic role of neutrophil lymphocyte ratio perturbations in the leading non communicable lifestyle diseases

Inflammation plays a critical role in the development and progression of chronic diseases like type 2 diabetes mellitus, coronary artery disease, and chronic obstructive pulmonary disease. Inflammatory responses are indispensable for pathogen control and tissue repair, but they also cause collateral damage. A chronically activated immune system and the resultant immune dysregulation mediated inflammatory surge may cause multiple negative effects, requiring tight regulation and dampening of the immune response to minimize host injury.  While chronic diseases are characterized by systemic inflammation, the mechanistic relationship of neutrophils and lymphocytes to inflammation and its correlation with the clinical outcomes is yet to be elucidated. The neutrophil to lymphocyte ratio (NLR) is an easy-to-measure laboratory marker used to assess systemic inflammation. Understanding the mechanisms of NLR perturbations in chronic diseases is crucial for risk stratification, early intervention, and finding novel therapeutic targets. We investigated the correlation between NLR and prevalent chronic conditions as a measure of systemic inflammation. In addition to predicting the risk of impending chronic conditions, NLR may also provide insight into their progression. This review summarizes the mechanisms of NLR perturbations at cellular and molecular levels, and the key inflammatory signaling pathways involved in the progression of chronic diseases. We have also explored preclinical studies investigating these pathways and the effect of quelling inflammation in chronic disease as reported by a few in vitro, in vivo studies, and clinical trials.

Modulation of mTOR Signaling in Cardiovascular Disease to Target Acute and Chronic Inflammation

Inflammation is a key component in the pathogenesis of cardiovascular diseases causing a significant burden of morbidity and mortality worldwide. Recent research shows that mammalian target of rapamycin (mTOR) signaling plays an important role in the general and inflammation-driven mechanisms that underpin cardiovascular disease. mTOR kinase acts prominently in signaling pathways that govern essential cellular activities including growth, proliferation, motility, energy consumption, and survival. Since the development of drugs targeting mTOR, there is proven efficacy in terms of survival benefit in cancer and allograft rejection. This review presents current information and concepts of mTOR activity in myocardial infarction and atherosclerosis, two important instances of cardiovascular illness involving acute and chronic inflammation. In experimental models, inhibition of mTOR signaling reduces myocardial infarct size, enhances functional remodeling, and lowers the overall burden of atheroma. Aside from the well-known effects of mTOR inhibition, which are suppression of growth and general metabolic activity, mTOR also impacts on specific leukocyte subpopulations and inflammatory processes. Inflammatory cell abundance is decreased due to lower migratory capacity, decreased production of chemoattractants and cytokines, and attenuated proliferation. In contrast to the generally suppressed growth signals, anti-inflammatory cell types such as regulatory T cells and reparative macrophages are enriched and activated, promoting resolution of inflammation and tissue regeneration. Nonetheless, given its involvement in the control of major cellular pathways and the maintenance of a functional immune response, modification of this system necessitates a balanced and time-limited approach. Overall, this review will focus on the advancements, prospects, and limits of regulating mTOR signaling in cardiovascular disease.

Myocardial-Treg Crosstalk: How to Tame a Wolf

The immune system plays a vital role in maintaining tissue integrity and organismal homeostasis. The sudden stress caused by myocardial infarction (MI) poses a significant challenge for the immune system: it must quickly substitute dead myocardial with fibrotic tissue while controlling overt inflammatory responses. In this review, we will discuss the central role of myocardial regulatory T-cells (Tregs) in orchestrating tissue repair processes and controlling local inflammation in the context of MI. We herein compile recent advances enabled by the use of transgenic mouse models with defined cardiac antigen specificity, explore whole-heart imaging techniques, outline clinical studies and summarize deep-phenotyping conducted by independent labs using single-cell transcriptomics and T-cell repertoire analysis. Furthermore, we point to multiple mechanisms and cell types targeted by Tregs in the infarcted heart, ranging from pro-fibrotic responses in mesenchymal cells to local immune modulation in myeloid and lymphoid lineages. We also discuss how both cardiac-specific and polyclonal Tregs participate in MI repair. In addition, we consider intriguing novel evidence on how the myocardial milieu takes control of potentially auto-aggressive local immune reactions by shaping myosin-specific T-cell development towards a regulatory phenotype. Finally, we examine the potential use of Treg manipulating drugs in the clinic after MI.

Immune and Inflammatory Networks in Myocardial Infarction: Current Research and Its Potential Implications for the Clinic

Despite recent scientific and technological advances, myocardial infarction (MI) still represents a major global health problem, leading to high morbidity and mortality worldwide. During the post-MI wound healing process, dysregulated immune inflammatory pathways and failure to resolve inflammation are associated with maladaptive left ventricular remodeling, progressive heart failure, and eventually poor outcomes. Given the roles of immune cells in the host response against tissue injury, understanding the involved cellular subsets, sources, and functions is essential for discovering novel therapeutic strategies that preserve the protective immune system and promote optimal healing. This review discusses the cellular effectors and molecular signals across multi-organ systems, which regulate the inflammatory and reparative responses after MI. Additionally, we summarize the recent clinical and preclinical data that propel conceptual revolutions in cardiovascular immunotherapy.

P2Y12-dependent activation of hematopoietic stem and progenitor cells promotes emergency hematopoiesis after myocardial infarction

Emergency hematopoiesis is the driving force of the inflammatory response to myocardial infarction (MI). Increased proliferation of hematopoietic stem and progenitor cells (LSK) after MI enhances cell production in the bone marrow (BM) and replenishes leukocyte supply for local cell recruitment to the infarct. Decoding the regulation of the inflammatory cascade after MI may provide new avenues to improve post-MI remodeling. In this study, we describe the influence of adenosine diphosphate (ADP)-dependent P2Y₁₂-mediated signaling on emergency hematopoiesis and cardiac remodeling after MI. Permanent coronary ligation was performed to induce MI in a murine model. BM activation, inflammatory cell composition and cardiac function were assessed using global and platelet-specific gene knockout and pharmacological inhibition models for P2Y₁₂. Complementary in vitro studies allowed for investigation of ADP-dependent effects on LSK cells. We found that ADP acts as a danger signal for the hematopoietic BM and fosters emergency hematopoiesis by promoting Akt phosphorylation and cell cycle progression. We were able to detect P2Y₁₂ in LSK, implicating a direct effect of ADP on LSK via P2Y₁₂ signaling. P2Y₁₂ knockout and P2Y₁₂ inhibitor treatment with prasugrel reduced emergency hematopoiesis and the excessive inflammatory response to MI, translating to lower numbers of downstream progeny and inflammatory cells in the blood and infarct. Ultimately, P2Y₁₂ inhibition preserved cardiac function and reduced chronic adverse cardiac remodeling after MI. P2Y₁₂-dependent signaling is involved in emergency hematopoiesis after MI and fuels post-ischemic inflammation, proposing a novel, non-canonical value for P2Y₁₂ antagonists beyond inhibition of platelet-mediated atherothrombosis.

The role of lymphangiogenesis in cardiovascular diseases and heart transplantation

Cardiac lymphangiogenesis plays an important physiological role in the regulation of interstitial fluid homeostasis, inflammatory, and immune responses. Impaired or excessive cardiac lymphatic remodeling and insufficient lymph drainage have been implicated in several cardiovascular diseases including atherosclerosis and myocardial infarction (MI). Although the molecular mechanisms underlying the regulation of functional lymphatics are not fully understood, the interplay between lymphangiogenesis and immune regulation has recently been explored in relation to the initiation and development of these diseases. In this field, experimental therapeutic strategies targeting lymphangiogenesis have shown promise by reducing myocardial inflammation, edema and fibrosis, and improving cardiac function. On the other hand, however, whether lymphangiogenesis is beneficial or detrimental to cardiac transplant survival remains controversial. In the light of recent evidence, cardiac lymphangiogenesis, a thriving and challenging field has been summarized and discussed, which may improve our knowledge in the pathogenesis of cardiovascular diseases and transplant biology.

Coronary vasodilation mediated by T cells expressing choline acetyltransferase

CD4⁺ T cells expressing choline acetyltransferase (ChAT) have recently been shown to cause a drop in systemic blood pressure when infused into mice. The aim of this study was to determine if ChAT-expressing T cells could regulate coronary vascular reactivity. Preconstricted segments of epicardial and intramyocardial porcine coronary arteries relaxed in response to Jurkat T cells (JT) that overexpressed ChAT (JT_ChAT cells). The efficacy of the JT_ChAT cells was similar in epicardial and intramyocardial vessels with a maximum dilator response to 3 × 10⁵ cells/mL of 38.0 ± 6.7% and 38.7 ± 7.25%, respectively. In contrast, nontransfected JT cells elicited a weak dilator response, followed by a weak contraction. The response of JT_ChAT cells was dependent on the presence of the endothelial cells. In addition, the response could be significantly reduced by N^ω-nitro-l-arginine methyl ester (l-NAME) and 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) in the presence of indomethacin. JT_ChAT cells, but not JT cells, increased the expression of phosphorylated endothelial nitric oxide synthase (eNOS). JT_ChAT cells contained significantly greater levels of acetylcholine compared with JT cells; however, the nonselective muscarinic antagonist atropine and the M₁ receptor antagonist pirenzepine both failed to block the dilator effect of JT_ChAT cells. Exogenously added acetylcholine induced only a weak relaxation (∼10%) at low concentrations, which became a contractile response at higher concentrations. These data illustrate the capacity for cells that express ChAT to regulate coronary vascular reactivity, via mechanisms that are dependent on interaction with the endothelium and in part mediated by the release of nitric oxide.NEW & NOTEWORTHY This study shows ChAT-expressing T cells can induce vasodilation of the blood vessel in the coronary circulation and that this effect relies on a direct interaction between T cells and the coronary vascular endothelium. The study establishes a potential immunomodulatory role for T cells in the coronary circulation. The present findings offer an additional possibility that a deficiency of ChAT-expressing T cells could contribute to reduced coronary blood flow and ischemic events in the myocardium.

Lack of gamma delta T cells ameliorates inflammatory response after acute intestinal ischemia reperfusion in mice

T-cells have been demonstrated to modulate ischemia–reperfusion injury (IRI) in the kidney, lung, liver, and intestine. Whereas most T-cell subpopulations contribute primarily to the antigen-specific effector and memory phases of immunity, γδ-T-cells combine adaptive features with rapid, innate-like responses that can place them in the initiation phase of immune reactions. Therefore, we aimed to clarify the role of γδ-T-cells in intestinal IRI. Adult wild-type (WT) and γδ-T-cell-deficient mice were subjected to acute intestinal IRI. Gene expression of pro-inflammatory cytokines and influx of leukocyte subpopulations in the gut were assessed by qPCR and flow cytometry. Serum transaminases were measured as an indicator of distant organ IRI. Intestinal IRI led to increased influx of neutrophils, pro-inflammatory cytokine expression and LDH/ALT/AST elevation. Selective deficiency of γδ-T-cells significantly decreased pro-inflammatory cytokine levels and neutrophil infiltration in the gut following IRI compared to controls. Furthermore, γδ-T-cell deficiency resulted in decreased LDH and transaminases levels in sera, indicating amelioration of distant organ injury. Increasing evidence demonstrates a key role of T-cell subpopulations in IRI. We demonstrate that γδ-T-cell deficiency ameliorated pro-inflammatory cytokine production, neutrophil recruitment and distant organ injury. Thus, γδ-T-cells may be considered as mediators contributing to the inflammatory response in the acute phase of intestinal IRI.

Cellular mechanisms and pathways in myocardial reperfusion injury

Despite the progress of cardiovascular medicine, ischemia-reperfusion injury can contribute to increased mortality and prolonged hospitalization after myocardial infarction. Ischemia-reperfusion injury pathophysiology encompasses many cells including cardiomyocytes, fibroblasts, mesenchymal stromal cells, vascular endothelial and smooth muscle cells, platelets, polymorphonuclear cells, macrophages, and T lymphocytes. However, specific mechanisms for all contributing cells and molecular pathways are still under investigation. What is definitely known is that endothelial dysfunction, immunity activation and inflammatory response are crucial events during ischemia-reperfusion injury while toll-like receptors, inflammasomes, reactive oxygen species, intracellular calcium overload and mitochondrial permeability transition pore opening consist of key molecular mediators. Indicatively, cardiac fibroblasts through inflammasome activation mediate the initial inflammatory response. Cardiac mesenchymal stromal cells can respond to myocardial injury by pro-inflammatory activation. Endothelial cell activation contributes to the impaired vasomotion, inflammation and thrombotic events and together with platelet activation leads to microcirculation dysfunction and polymorphonuclear cells recruitment promoting inflammation. Polymorphonuclear cells and monocytes/macrophages subsets are critically involved in the inflammation process by producing toxic proteolytic enzymes and reactive oxygen species. T cells subsets are also involved in several stages of ischemia-reperfusion injury. In this review, we summarize the specific contribution of each of the above cells and the related molecular pathways in the pathophysiology of ischemia-reperfusion injury.

Roles and Mechanisms of TGR5 in the Modulation of CD4+ T Cell Functions in Myocardial Infarction

Bile acid receptor TGR5 has been proved to play protective roles in the process of myocardial infarction (MI). Recently, we found spleen weight of Tgr5^+/+ mice was increased at 7-day post-MI but not in Tgr5^-/- mice. Since the spleen is one of the main resources of immune and inflammatory cells post-MI, we conducted flow cytometry analysis of multiple immune cells in the heart post-MI. It showed the recruitment of CD4⁺ T cells and CD8⁺ T cells was continuously more in the heart of Tgr5^-/- mice post-MI until 7 days after MI. Furthermore, CD4-specific TGR5 depletion mice exhibited aggravated ischemic injury. The mRNA expressions of the markers of Th1 and Treg were upregulated in the heart of Tgr5^-/- mice at 7-day post-MI. These results suggested TGR5 modulates CD4⁺ T cell functions and subsets distribution in the heart, and plays protective roles in myocardial infarction.

Regulatory B cells improve ventricular remodeling after myocardial infarction by modulating monocyte migration

Overactivated inflammatory responses contribute to adverse ventricular remodeling after myocardial infarction (MI). Regulatory B cells (Bregs) are a newly discovered subset of B cells with immunomodulatory roles in many immune and inflammation-related diseases. Our study aims to determine whether the expansion of Bregs exerts a beneficial effect on ventricular remodeling and explore the mechanisms involved. Here, we showed that adoptive transfer of Bregs ameliorated ventricular remodeling in a murine MI model, as demonstrated by improved cardiac function, decreased scar size and attenuated interstitial fibrosis without changing the survival rate. Reduced Ly6C^hi monocyte infiltration was found in the hearts of the Breg-transferred mice, while the infiltration of Ly6C^lo monocytes was not affected. In addition, the replenishment of Bregs had no effect on the myocardial accumulation of T cells or neutrophils. Mechanistically, Bregs reduced the expression of C-C motif chemokine receptor 2 (CCR2) in monocytes, which inhibited proinflammatory monocyte recruitment to the heart from the peripheral blood and mobilization from the bone marrow. Breg-mediated protection against MI was abrogated by treatment with an interleukin 10 (IL-10) antibody. Finally, IL-10 neutralization reversed the effect of Bregs on monocyte migration and CCR2 expression. The present study suggests a therapeutic value of Bregs in limiting ventricular remodeling after MI through decreasing CCR2-mediated monocyte recruitment and mobilization.

Cholinergic stimulation with pyridostigmine modulates a heart-spleen axis after acute myocardial infarction in spontaneous hypertensive rats

The mechanisms regulating immune cells recruitment into the heart during healing after an acute myocardial infarction (AMI) have major clinical implications. We investigated whether cholinergic stimulation with pyridostigmine, a cholinesterase inhibitor, modulates heart and spleen immune responses and cardiac remodeling after AMI in spontaneous hypertensive rats (SHRs). Male adult SHRs underwent sham surgery or ligation of the left coronary artery and were randomly allocated to remain untreated or to pyridostigmine treatment (40 mg/kg once a day by gavage). Blood pressure and heart rate variability were determined, and echocardiography was performed at day six after MI. The heart and spleen were processed for immunohistochemistry cellular analyses (CD3⁺ and CD4⁺ lymphocytes, and CD68⁺ and CD206⁺ macrophages), and TNF levels were determined at day seven after MI. Pyridostigmine treatment increased the parasympathetic tone and T CD4⁺ lymphocytes in the myocardium, but lowered M1/M2 macrophage ratio towards an anti-inflammatory profile that was associated with decreased TNF levels in the heart and spleen. Treatment with this cholinergic agent improved heart remodeling manifested by lower ventricular diameters and better functional parameters. In summary, cholinergic stimulation by pyridostigmine enhances the parasympathetic tone and induces anti-inflammatory responses in the heart and spleen fostering cardiac recovery after AMI in SHRs.