Interleukin-10 Inhibits Bone Marrow Fibroblast Progenitor Cell-Mediated Cardiac Fibrosis in Pressure-Overloaded Myocardium

Long-Term Dietary Consumption of Grapes Affects Kidney Health in C57BL/6J Mice

Starting at 4 weeks of age, male and female C57BL/6J mice were provided with a semi-synthetic diet for a period of one year and then continued on the semi-synthetic diet with or without grape supplementation for the duration of their lives. During the course of the study, no variation of body weights was noted between the groups. At 2.5 years of age, the body-weight-to-tissue-weight ratios did not vary for the liver, colon, muscle, prostate, or ovary. However, relative to the standard diet, the body/kidney weight ratio was significantly lower in the male and female groups with grape-supplemented diets. With the mice provided with the standard diet, the BUN/creatinine ratios were 125 and 152 for males and females, respectively, and reduced to 63.7 and 40.4, respectively, when provided with the grape diet. A histological evaluation suggested that this may be due to enhanced/improved perfusion in the kidney as a preventive/protective effect. In response to the dietary grapes, an RNA seq analysis revealed up-regulation of 21 and 109 genes with male and female mice, respectively, with a corresponding down-regulation of 108 and 65 genes. The downward movement of the FPKM values in the males (alox5, btk, fga, fpr1, hmox1, lox, ltf, lyve1, marco, mmp8, prg4, s100a8/9, serpina3n, and vsig4) and upward movement of the FPKM values in the females (camp, cd300lf, cd72, fcgr4, fgr, fpr2, htra4, il10, lilrb4b, lipg, pilra, and tlr8) suggest beneficial kidney effects. The expression of some genes related to the immunological activity was also modulated by the grape diet, mainly downward in the males and upward in the females. The reactome pathway analysis, KEGG analysis, and GSEA normalized enrichment scores illustrate that several pathways related to immune function, collagenase degradation, extracellular matrix regulation, metabolism of vitamins and cofactors, pancreatic secretion, aging, and mitochondrial function were enriched in both the males and females provided with the grape diet. Overall, these results indicate that the long-term dietary consumption of grapes contributes to renal health and resilience against fibrosis and related pathologies.

Exploring the role of granzyme B in subretinal fibrosis of age-related macular degeneration

Age-related macular degeneration (AMD), a prevalent and progressive degenerative disease of the macula, is the leading cause of blindness in elderly individuals in developed countries. The advanced stages include neovascular AMD (nAMD), characterized by choroidal neovascularization (CNV), leading to subretinal fibrosis and permanent vision loss. Despite the efficacy of anti-vascular endothelial growth factor (VEGF) therapy in stabilizing or improving vision in nAMD, the development of subretinal fibrosis following CNV remains a significant concern. In this review, we explore multifaceted aspects of subretinal fibrosis in nAMD, focusing on its clinical manifestations, risk factors, and underlying pathophysiology. We also outline the potential sources of myofibroblast precursors and inflammatory mechanisms underlying their recruitment and transdifferentiation. Special attention is given to the potential role of mast cells in CNV and subretinal fibrosis, with a focus on putative mast cell mediators, tryptase and granzyme B. We summarize our findings on the role of GzmB in CNV and speculate how GzmB may be involved in the pathological transition from CNV to subretinal fibrosis in nAMD. Finally, we discuss the advantages and drawbacks of animal models of subretinal fibrosis and pinpoint potential therapeutic targets for subretinal fibrosis.

Mesenchymal stem cells may alleviate angiotensin II-induced myocardial fibrosis and hypertrophy by upregulating SFRS3 expression

INTRODUCTION AND OBJECTIVES

The development of cardiac fibrosis (CF) and hypertrophy (CH) can lead to heart failure. Mesenchymal stem cells (MSCs) have shown promise in treating cardiac diseases. However, the relationship between MSCs and splicing factor arginine/serine rich-3 (SFRS3) remains unclear. In this study, our objectives are to investigate the effect of MSCs on SFRS3 expression, and their impact on CF and CH. Additionally, we aim to explore the function of the overexpression of SFRS3 in angiotensin II (Ang II)-treated cardiac fibroblasts (CFBs) and cardiac myocytes (CMCs).

METHODS

Rat cardiac fibroblasts (rCFBs) or rat cardiac myocytes (rCMCs) were co-cultured with rat MSCs (rMSCs). The function of SFRS3 in Ang II-induced rCFBs and rCMCs was studied by overexpressing SFRS3 in these cells, both with and without the presence of rMSCs. We assessed the expression of SFRS3 and evaluated the cell cycle, proliferation and apoptosis of rCFBs and rCMCs. We also measured the levels of interleukin (IL)-β, IL-6 and tumor necrosis factor (TNF)-α and assessed the degree of fibrosis in rCFBs and hypertrophy in rCMCs.

RESULTS

rMSCs induced SFRS3 expression and promoted cell cycle, proliferation, while reducing apoptosis of Ang II-treated rCFBs and rCMCs. Co-culture of rMSCs with these cells also repressed cytokine production and mitigated the fibrosis of rCFBs, as well as hypertrophy of rCMCs triggered by Ang II. Overexpression of SFRS3 in the rCFBs and rCMCs yielded identical effects to rMSC co-culture.

CONCLUSION

MSCs may alleviate Ang II-induced cardiac fibrosis and cardiomyocyte hypertrophy by increasing SFRS3 expression in vitro.

Interleukin-5 alleviates cardiac remodelling via the STAT3 pathway in angiotensin II-infused mice

Interleukin-5 (IL-5) has been reported to be involved in cardiovascular diseases, such as atherosclerosis and cardiac injury. This study aimed to investigate the effects of IL-5 on cardiac remodelling. Mice were infused with angiotensin II (Ang II), and the expression and source of cardiac IL-5 were analysed. The results showed that cardiac IL-5 expression was time- and dose-dependently decreased after Ang II infusion, and was mainly derived from cardiac macrophages. Additionally, IL-5-knockout (IL-5-/-) mice were used to observe the effects of IL-5 knockout on Ang II-induced cardiac remodelling. We found knockout of IL-5 significantly increased the expression of cardiac hypertrophy markers, elevated myocardial cell cross-sectional areas and worsened cardiac dysfunction in Ang II-infused mice. IL-5 deletion also promoted M2 macrophage differentiation and exacerbated cardiac fibrosis. Furthermore, the effects of IL-5 deletion on cardiac remodelling was detected after the STAT3 pathway was inhibited by S31-201. The effects of IL-5 on cardiac remodelling and M2 macrophage differentiation were reversed by S31-201. Finally, the effects of IL-5 on macrophage differentiation and macrophage-related cardiac hypertrophy and fibrosis were analysed in vitro. IL-5 knockout significantly increased the Ang II-induced mRNA expression of cardiac hypertrophy markers in myocardial cells that were co-cultured with macrophages, and this effect was reversed by S31-201. Similar trends in the mRNA levels of fibrosis markers were observed when cardiac fibroblasts and macrophages were co-cultured. In conclusions, IL-5 deficiency promote the differentiation of M2 macrophages by activating the STAT3 pathway, thereby exacerbating cardiac remodelling in Ang II-infused mice. IL-5 may be a potential target for the clinical prevention of cardiac remodelling.

Bone marrow-fibroblast progenitor cell-derived small extracellular vesicles promote cardiac fibrosis via miR-21-5p and integrin subunit αV signalling

Cardiac fibrosis is the hallmark of cardiovascular disease (CVD), which is leading cause of death worldwide. Previously, we have shown that interleukin-10 (IL10) reduces pressure overload (PO)-induced cardiac fibrosis by inhibiting the recruitment of bone marrow fibroblast progenitor cells (FPCs) to the heart. However, the precise mechanism of FPC involvement in cardiac fibrosis remains unclear. Recently, exosomes and small extracellular vesicles (sEVs) have been linked to CVD progression. Thus, we hypothesized that pro-fibrotic miRNAs enriched in sEV-derived from IL10 KO FPCs promote cardiac fibrosis in pressure-overloaded myocardium. Small EVs were isolated from FPCs cultured media and characterized as per MISEV-2018 guidelines. Small EV's miRNA profiling was performed using Qiagen fibrosis-associated miRNA profiler kit. For functional analysis, sEVs were injected in the heart following TAC surgery. Interestingly, TGFβ-treated IL10-KO-FPCs sEV increased profibrotic genes expression in cardiac fibroblasts. The exosomal miRNA profiling identified miR-21a-5p as the key player, and its inhibition with antagomir prevented profibrotic signalling and fibrosis. At mechanistic level, miR-21a-5p binds and stabilizes ITGAV (integrin av) mRNA. Finally, miR-21a-5p-silenced in sEV reduced PO-induced cardiac fibrosis and improved cardiac function. Our study elucidates the mechanism by which inflammatory FPC-derived sEV exacerbate cardiac fibrosis through the miR-21a-5p/ITGAV/Col1α signalling pathway, suggesting miR-21a-5p as a potential therapeutic target for treating hypertrophic cardiac remodelling and heart failure.

Macrophages in cardiovascular diseases: molecular mechanisms and therapeutic targets

The immune response holds a pivotal role in cardiovascular disease development. As multifunctional cells of the innate immune system, macrophages play an essential role in initial inflammatory response that occurs following cardiovascular injury, thereby inducing subsequent damage while also facilitating recovery. Meanwhile, the diverse phenotypes and phenotypic alterations of macrophages strongly associate with distinct types and severity of cardiovascular diseases, including coronary heart disease, valvular disease, myocarditis, cardiomyopathy, heart failure, atherosclerosis and aneurysm, which underscores the importance of investigating macrophage regulatory mechanisms within the context of specific diseases. Besides, recent strides in single-cell sequencing technologies have revealed macrophage heterogeneity, cell-cell interactions, and downstream mechanisms of therapeutic targets at a higher resolution, which brings new perspectives into macrophage-mediated mechanisms and potential therapeutic targets in cardiovascular diseases. Remarkably, myocardial fibrosis, a prevalent characteristic in most cardiac diseases, remains a formidable clinical challenge, necessitating a profound investigation into the impact of macrophages on myocardial fibrosis within the context of cardiac diseases. In this review, we systematically summarize the diverse phenotypic and functional plasticity of macrophages in regulatory mechanisms of cardiovascular diseases and unprecedented insights introduced by single-cell sequencing technologies, with a focus on different causes and characteristics of diseases, especially the relationship between inflammation and fibrosis in cardiac diseases (myocardial infarction, pressure overload, myocarditis, dilated cardiomyopathy, diabetic cardiomyopathy and cardiac aging) and the relationship between inflammation and vascular injury in vascular diseases (atherosclerosis and aneurysm). Finally, we also highlight the preclinical/clinical macrophage targeting strategies and translational implications.

Biomarker and transcriptomics profiles of serum selenium concentrations in patients with heart failure are associated with immunoregulatory processes

BACKGROUND

Low selenium concentrations are associated with worse outcomes in heart failure (HF). However, the underlying pathophysiologic mechanisms remain incompletely understood. Therefore, we aimed to contrast serum selenium concentrations to blood biomarker and transcriptomic profiles in patients with HF.

METHODS

Circulating biomarkers, whole blood transcriptomics and serum selenium measurements in a cohort of 2328 patients with HF were utilized. Penalized linear regression and gene expression analysis were used to assess biomarker and transcriptomics profiles, respectively. As a proof-of-principle, potential causal effects of selenium on excreted cytokines concentrations were investigated using human peripheral blood mononuclear cells (PBMCs).

RESULTS

Mean selenium levels were 60.6 μg/L in Q1 and 122.0 μg/L in Q4. From 356 biomarkers and 20 clinical features, the penalized linear regression model yielded 44 variables with <5 % marginal false discovery rate as predictors of serum selenium. Biomarkers associated positively with selenium concentrations included: epidermal growth factor receptor (EGFR), IFN-gamma-R1, CD4, GDF15, and IL10. Biomarkers associated negatively with selenium concentrations included: PCSK9, TNFSF13, FGF21 and PAI. Additionally, 148 RNA transcripts were found differentially expressed between high and low selenium status (Padj.<0.05; log-fold-change<|0.25|). Enrichment analyses of the selected biomarkers and RNA transcripts identified similar enriched processes, including regulation processes of leukocyte differentiation and activation, as well as cytokines production. The mRNA expression of two selenoproteins (MSRB1 and GPX4) were strongly correlated with serum selenium, while GPX4, SELENOK, and SELENOS were associated with prognosis. In the in-vitro setting, PBMCs supplemented with selenium showed significantly lower abundance of several (pro-)inflammatory cytokines.

CONCLUSION

These data suggest that immunoregulation is an important mechanism through which selenium might have beneficial roles in HF. The beneficial effects of higher serum selenium concentrations are likely because of global immunomodulatory effects on the abundance of cytokines. MSRB1 and GPX4 are potential modulators of and should be pursued in future research.

HBI-8000 improves heart failure with preserved ejection fraction via the TGF-β1/MAPK signalling pathway

Heart failure with preserved ejection fraction (HFpEF) accounts for approximately 50% of total heart failure patients and is characterized by peripheral circulation, cardiac remodelling and comorbidities (such as advanced age, obesity, hypertension and diabetes) with limited treatment options. Chidamide (HBI-8000) is a domestically produced benzamide-based histone deacetylase isoform-selective inhibitor used for the treatment of relapsed refractory peripheral T-cell lymphomas. Based on our in vivo studies, we propose that HBI-8000 exerts its therapeutic effects by inhibiting myocardial fibrosis and myocardial hypertrophy in HFpEF patients. At the cellular level, we found that HBI-8000 inhibits AngII-induced proliferation and activation of CFs and downregulates the expression of fibrosis-related factors. In addition, we observed that the HFpEF group and AngII stimulation significantly increased the expression of TGF-β1 as well as phosphorylated p38MAPK, JNK and ERK, whereas the expression of the above factors was significantly reduced after HBI-8000 treatment. Activation of the TGF-β1/MAPK pathway promotes the development of fibrotic remodelling, and pretreatment with SB203580 (p38MAPK inhibitor) reverses this pathological change. In conclusion, our data suggest that HBI-8000 inhibits fibrosis by modulating the TGF-β1/MAPK pathway thereby improving HFpEF. Therefore, HBI-8000 may become a new hope for the treatment of HFpEF patients.

Identification of diagnostic model in heart failure with myocardial fibrosis and conduction block by integrated gene co-expression network analysis

BACKGROUND

Despite the advancements in heart failure(HF) research, the early diagnosis of HF continues to be a challenging issue in clinical practice. This study aims to investigate the genes related to myocardial fibrosis and conduction block, with the goal of developing a diagnostic model for early treatment of HF in patients.

METHOD

The gene expression profiles of GSE57345, GSE16499, and GSE9128 were obtained from the Gene Expression Omnibus (GEO) database. After merging the expression profile data and adjusting for batch effects, differentially expressed genes (DEGs) associated with conduction block and myocardial fibrosis were identified. Gene Ontology (GO) resources, Kyoto Encyclopedia of Genes and Genomes (KEGG) resources, and gene set enrichment analysis (GSEA) were utilized for functional enrichment analysis. A protein-protein interaction network (PPI) was constructed using a string database. Potential key genes were selected based on the bioinformatics information mentioned above. SVM and LASSO were employed to identify hub genes and construct the module associated with HF. The mRNA levels of TAC mice and external datasets (GSE141910 and GSE59867) are utilized for validating the diagnostic model. Additionally, the study explores the relationship between the diagnostic model and immune cell infiltration.

RESULTS

A total of 395 genes exhibiting differential expression were identified. Functional enrichment analysis revealed that these specific genes primarily participate in biological processes and pathways associated with the constituents of the extracellular matrix (ECM), immune system processes, and inflammatory responses. We identified a diagnostic model consisting of 16 hub genes, and its predictive performance was validated using external data sets and a transverse aortic coarctation (TAC) mouse model. In addition, we observed significant differences in mRNA expression of 7 genes in the TAC mouse model. Interestingly, our study also unveiled a correlation between these model genes and immune cell infiltration.

CONCLUSIONS

We identified sixteen key genes associated with myocardial fibrosis and conduction block, as well as diagnostic models for heart failure. Our findings have significant implications for the intensive management of individuals with potential genetic variants associated with heart failure, especially in the context of advancing cell-targeted therapy for myocardial fibrosis.

Exosomes Isolation, Purification, and Characterization

Exosomes are double-layered lipid membranous nanovesicles that are endosomal in origin and secreted by almost all cells. They are 30-130 nm in size and contain various molecular signatures such as miRNAs, mRNAs, DNA, lipids, and proteins. Due to their highly heterogeneous content, exosomes have a major role in influencing cellular physiology and pathology. Although exosome research has been in progress for a long time, its biomedical applications have recently been expanding due to its bio-friendly nature. However, the most challenging part is its isolation to obtain quality exosomes with good yield. Therefore, in this chapter, we have described appropriate protocols for exosome isolation and characterization along with alternative purification methods.

p53 and Myofibroblast Apoptosis in Organ Fibrosis

Organ fibrosis represents a dysregulated, maladaptive wound repair response that results in progressive disruption of normal tissue architecture leading to detrimental deterioration in physiological function, and significant morbidity/mortality. Fibrosis is thought to contribute to nearly 50% of all deaths in the Western world with current treatment modalities effective in slowing disease progression but not effective in restoring organ function or reversing fibrotic changes. When physiological wound repair is complete, myofibroblasts are programmed to undergo cell death and self-clearance, however, in fibrosis there is a characteristic absence of myofibroblast apoptosis. It has been shown that in fibrosis, myofibroblasts adopt an apoptotic-resistant, highly proliferative phenotype leading to persistent myofibroblast activation and perpetuation of the fibrotic disease process. Recently, this pathological adaptation has been linked to dysregulated expression of tumour suppressor gene p53. In this review, we discuss p53 dysregulation and apoptotic failure in myofibroblasts and demonstrate its consistent link to fibrotic disease development in all types of organ fibrosis. An enhanced understanding of the role of p53 dysregulation and myofibroblast apoptosis may aid in future novel therapeutic and/or diagnostic strategies in organ fibrosis.

Signaling Pathways and Potential Therapeutic Strategies in Cardiac Fibrosis

Cardiac fibrosis constitutes irreversible necrosis of the heart muscle as a consequence of different acute (myocardial infarction) or chronic (diabetes, hypertension, …) diseases but also due to genetic alterations or aging. Currently, there is no curative treatment that is able to prevent or attenuate this phenomenon that leads to progressive cardiac dysfunction and life-threatening outcomes. This review summarizes the different targets identified and the new strategies proposed to fight cardiac fibrosis. Future directions, including the use of exosomes or nanoparticles, will also be discussed.

Adenovirus-IL-10 relieves chronic rejection after mouse heart transplantation by inhibiting miR-155 and activating SOCS5

Objective: Chronic rejection remains the main factor that influence long-term survival of patients after heart transplantation. Interleukin-10 (IL-10) play critical role in macrophages-mediated transplant immune responses. We investigated the mechanism of IL-10 in macrophage related chronic rejection after mouse heart transplantation. Methods: Mouse heart transplant chronic rejection model was established to evaluate pathological changes in the allograft. Myocardial interstitial fibrosis, apoptosis, and inflammatory factor levels were detected in ad-IL-10-treated mice. The positive iNOS⁺ and Arg-1⁺ expressions, macrophage subset changes, and the proportion of regulatory T-cells (Tregs) and TIGIT⁺ Tregs were quantified by flow. In in vitro experiments, ad-IL-10 was transfected into macrophages followed by detection of apoptosis, phagocytosis, and CD163, CD16/32, and CD206 expression. The expression and relationships between IL-10, miR-155, and SOCS5 were also detected and verified. A rescue experiment was performed to evaluate macrophage function through the combined treatment of ad-IL-10 and overexpression of miR-155. Results: Significantly decreased IL-10 expression in chronic rejection during mouse heart transplantation was observed. Ad-IL-10-treated mice showed decreased pathological injury, perivascular fibrosis, apoptosis, inflammation, and iNOS⁺ and CD16/32⁺ expression, and increased Treg/TIGIT⁺ Treg cell, Arg-1⁺ and CD206⁺ cell proportion. Ad-IL-10-treated macrophages in vitro showed reduced apoptosis, improved phagocytosis, and M2 polarization. Mechanically, IL-10 negatively regulated miR-155 to activate SOCS5. Overexpression of miR-155 reversed IL-10 mediated-positive regulation of macrophage function. Conclusion: IL-10 downregulated miR-155 and activated SOCS5, thereby promoting macrophage M2 polarization to relieve chronic rejection after heart transplantation.

Eicosapentaenoic Acid Ameliorates Cardiac Fibrosis and Tissue Inflammation in Spontaneously Hypertensive Rats

Hypertension affects 1 in 3 adults in the United States and leads to left ventricular (LV) concentric hypertrophy, interstitial fibrosis, and increased stiffness. The treatment of cardiac fibrosis remains challenging and empiric. Eicosapentaenoic acid (EPA) is an omega-3 polyunsaturated fatty acid that is highly effective in reducing cardiovascular events in patients and cardiac fibrosis and hypertrophy in animals when administered before pressure overload by promoting the increase of anti-inflammatory M1 macrophages. In this study, we investigated whether EPA mitigates the exacerbation of cardiac remodeling and fibrosis induced by established hypertension, a situation that closely recapitulates a clinical scenario. Twelve-week-old spontaneously hypertensive rats were randomized to eat an EPA-enriched or control diet for 20 weeks. We report that rats eating the EPA-enriched diet exhibited a reduction of interstitial cardiac fibrosis and ameliorated LV diastolic dysfunction despite the continuous increase in blood pressure. However, we found that EPA did not have an impact on cardiac hypertrophy. Interestingly, the EPA diet increased mRNA expression of M2 macrophage marker Mrc1 and interleukin-10 in cardiac tissue. These findings indicated that the antifibrotic effects of EPA are mediated in part by phenotypic polarization of macrophages toward anti-inflammatory M2 macrophages and increases of the anti-inflammatory cytokine, interleukin-10. In summary, EPA prevents the exacerbation of cardiac fibrosis and LV diastolic dysfunction during sustained pressure overload. EPA could represent a novel treatment strategy for hypertensive cardiomyopathy.

Macrophage, a potential targeted therapeutic immune cell for cardiomyopathy

Cardiomyopathy is a major cause of heart failure, leading to systolic and diastolic dysfunction and promoting adverse cardiac remodeling. Macrophages, as key immune cells of the heart, play a crucial role in inflammation and fibrosis. Moreover, exogenous and cardiac resident macrophages are functionally and phenotypically different during cardiac injury. Although experimental evidence has shown that macrophage-targeted therapy is promising in cardiomyopathy, clinical translation remains challenging. In this article, the molecular mechanism of macrophages in cardiomyopathy has been discussed in detail based on existing literature. The issues and considerations of clinical treatment strategies for myocardial fibrosis has also been analyzed.

Non-coding RNAs: Important participants in cardiac fibrosis

Cardiac remodeling is a pathophysiological process activated by diverse cardiac stress, which impairs cardiac function and leads to adverse clinical outcome. This remodeling partly attributes to cardiac fibrosis, which is a result of differentiation of cardiac fibroblasts to myofibroblasts and the production of excessive extracellular matrix within the myocardium. Non-coding RNAs mainly include microRNAs and long non-coding RNAs. These non-coding RNAs have been proved to have a profound impact on biological behaviors of various cardiac cell types and play a pivotal role in the development of cardiac fibrosis. This review aims to summarize the role of microRNAs and long non-coding RNAs in cardiac fibrosis associated with pressure overload, ischemia, diabetes mellitus, aging, atrial fibrillation and heart transplantation, meanwhile shed light on the diagnostic and therapeutic potential of non-coding RNAs for cardiac fibrosis.

Cardiac Mast Cells: A Two-Head Regulator in Cardiac Homeostasis and Pathogenesis Following Injury

Cardiac mast cells (CMCs) are multifarious immune cells with complex roles both in cardiac physiological and pathological conditions, especially in cardiac fibrosis. Little is known about the physiological importance of CMCs in cardiac homeostasis and inflammatory process. Therefore, the present review will summarize the recent progress of CMCs on origin, development and replenishment in the heart, including their effects on cardiac development, function and ageing under physiological conditions as well as the roles of CMCs in inflammatory progression and resolution. The present review will shed a light on scientists to understand cardioimmunology and to develop immune treatments targeting on CMCs following cardiac injury.

Intermedin1-53 Inhibits NLRP3 Inflammasome Activation by Targeting IRE1α in Cardiac Fibrosis

Intermedin (IMD), a paracrine/autocrine peptide, protects against cardiac fibrosis. However, the underlying mechanism remains poorly understood. Previous study reports that activation of nucleotide-binding oligomerization domain (NOD)-like receptor family pyrin domain containing 3 (NLRP3) inflammasome contributes to cardiac fibrosis. In this study, we aimed to investigate whether IMD mitigated cardiac fibrosis by inhibiting NLRP3. Cardiac fibrosis was induced by angiotensin II (Ang II) infusion for 2 weeks in rats. Western blot, real-time PCR, histological staining, immunofluorescence assay, RNA sequencing, echocardiography, and hemodynamics were used to detect the role and the mechanism of IMD in cardiac fibrosis. Ang II infusion resulted in rat cardiac fibrosis, shown as over-deposition of myocardial interstitial collagen and cardiac dysfunction. Importantly, NLRP3 activation and endoplasmic reticulum stress (ERS) were found in Ang II-treated rat myocardium. Ang II infusion decreased the expression of IMD and increased the expression of the receptor system of IMD in the fibrotic rat myocardium. IMD treatment attenuated the cardiac fibrosis and improved cardiac function. In addition, IMD inhibited the upregulation of NLRP3 markers and ERS markers induced by Ang II. In vitro, IMD knockdown by small interfering RNA significantly promoted the Ang II-induced cardiac fibroblast and NLRP3 activation. Moreover, silencing of inositol requiring enzyme 1 α (IRE1α) blocked the effects of IMD inhibiting fibroblast and NLRP3 activation. Pre-incubation with PKA pathway inhibitor H89 blocked the effects of IMD on the anti-ERS, anti-NLRP3, and anti-fibrotic response. In conclusion, IMD alleviated cardiac fibrosis by inhibiting NLRP3 inflammasome activation through suppressing IRE1α via the cAMP/PKA pathway.

Overview of First-Line and Second-Line Pharmacotherapies for Osteoarthritis with Special Focus on Intra-Articular Treatment

Osteoarthritis (OA) can be defined as the result of pathological processes of various etiologies leading to damage to the articular structures. Although the mechanism of degenerative changes has become better understood due to the plethora of biochemical and genetic studies, the drug that could stop the degenerative cascade is still unknown. All available forms of OA therapy are based on symptomatic treatment. According to actual guidelines, comprehensive treatment of OA should always include a combination of various therapeutic options aimed at common goals, which are pain relief in the first place, and then the improvement of function. Local treatment has become more common practice, which takes place between rehabilitation and pharmacological treatment in the hierarchy of procedures. Only in the case of no improvement and the presence of advanced lesions visible in imaging tests, should surgery be considered. Currently, an increasing number of studies are being published suggesting that intra-articular injections may be as effective or even more effective than non-steroidal anti-inflammatory drugs (NSAIDs) and result in fewer systemic adverse events. The most commonly used preparations are hyaluronic acid (HA), glucocorticosteroids (GS), and also platelet-rich plasma (PRP) in recent years. This review aims to present the mechanism of action and clinical effectiveness of different pharmacological options in relieving pain and improving functions in OA as well as the emerging approach in intra-articular treatment with PRP.

Cardiac Resident Macrophages Prevent Fibrosis and Stimulate Angiogenesis

Supplemental Digital Content is available in the text.

The initial hypertrophy response to cardiac pressure overload is considered compensatory, but with sustained stress, it eventually leads to heart failure. Recently, a role for recruited macrophages in determining the transition from compensated to decompensated hypertrophy has been established. However, whether cardiac resident immune cells influence the early phase of hypertrophy development has not been established.

Management of inflammation in cardiovascular diseases

Cardiovascular disease is the leading cause of morbidity and mortality world-wide. Recently, the role of inflammation in the progression of diseases has significantly attracted considerable attention. In addition, various comorbidities, including diabetes, obesity, etc. exacerbate inflammation in the cardiovascular system, which ultimately leads to heart failure. Furthermore, cytokines released from specialized immune cells are key mediators of cardiac inflammation. Here, in this review article, we focused on the role of selected immune cells and cytokines (both pro-inflammatory and anti-inflammatory) in the regulation of cardiac inflammation and ultimately in cardiovascular diseases. While IL-1β, IL-6, TNFα, and IFNγ are associated with cardiac inflammation; IL-10, TGFβ, etc. are associated with resolution of inflammation and cardiac repair. IL-10 reduces cardiovascular inflammation and protects the cardiovascular system via interaction with SMAD2, p53, HuR, miR-375 and miR-21 pathway. In addition, we also highlighted recent advancements in the management of cardiac inflammation, including clinical trials of anti-inflammatory molecules to alleviate cardiovascular diseases.

Cardiac Fibrosis: Cellular Effectors, Molecular Pathways, and Exosomal Roles

Cardiac fibrosis, a common pathophysiologic process in most heart diseases, refers to an excess of extracellular matrix (ECM) deposition by cardiac fibroblasts (CFs), which can lead to cardiac dysfunction and heart failure subsequently. Not only CFs but also several other cell types including macrophages and endothelial cells participate in the process of cardiac fibrosis via different molecular pathways. Exosomes, ranging in 30-150 nm of size, have been confirmed to play an essential role in cellular communications by their bioactive contents, which are currently a hot area to explore pathobiology and therapeutic strategy in multiple pathophysiologic processes including cardiac fibrosis. Cardioprotective factors such as RNAs and proteins packaged in exosomes make them an excellent cell-free system to improve cardiac function without significant immune response. Emerging evidence indicates that targeting selective molecules in cell-derived exosomes could be appealing therapeutic treatments in cardiac fibrosis. In this review, we summarize the current understandings of cellular effectors, molecular pathways, and exosomal roles in cardiac fibrosis.

Fibrosis of the diabetic heart: Clinical significance, molecular mechanisms, and therapeutic opportunities

In patients with diabetes, myocardial fibrosis may contribute to the pathogenesis of heart failure and arrhythmogenesis, increasing ventricular stiffness and delaying conduction. Diabetic myocardial fibrosis involves effects of hyperglycemia, lipotoxicity and insulin resistance on cardiac fibroblasts, directly resulting in increased matrix secretion, and activation of paracrine signaling in cardiomyocytes, immune and vascular cells, that release fibroblast-activating mediators. Neurohumoral pathways, cytokines, growth factors, oxidative stress, advanced glycation end-products (AGEs), and matricellular proteins have been implicated in diabetic fibrosis; however, the molecular links between the metabolic perturbations and activation of a fibrogenic program remain poorly understood. Although existing therapies using glucose- and lipid-lowering agents and neurohumoral inhibition may act in part by attenuating myocardial collagen deposition, specific therapies targeting the fibrotic response are lacking. This review manuscript discusses the clinical significance, molecular mechanisms and cell biology of diabetic cardiac fibrosis and proposes therapeutic targets that may attenuate the fibrotic response, preventing heart failure progression.

Electroimmunology and cardiac arrhythmia

Conduction disorders and arrhythmias remain difficult to treat and are increasingly prevalent owing to the increasing age and body mass of the general population, because both are risk factors for arrhythmia. Many of the underlying conditions that give rise to arrhythmia - including atrial fibrillation and ventricular arrhythmia, which frequently occur in patients with acute myocardial ischaemia or heart failure - can have an inflammatory component. In the past, inflammation was viewed mostly as an epiphenomenon associated with arrhythmia; however, the recently discovered inflammatory and non-canonical functions of cardiac immune cells indicate that leukocytes can be arrhythmogenic either by altering tissue composition or by interacting with cardiomyocytes; for example, by changing their phenotype or perhaps even by directly interfering with conduction. In this Review, we discuss the electrophysiological properties of leukocytes and how these cells relate to conduction in the heart. Given the thematic parallels, we also summarize the interactions between immune cells and neural systems that influence information transfer, extrapolating findings from the field of neuroscience to the heart and defining common themes. We aim to bridge the knowledge gap between electrophysiology and immunology, to promote conceptual connections between these two fields and to explore promising opportunities for future research.

Prognostic impact of baseline inflammatory markers in patients with acute coronary syndromes treated with ticagrelor and clopidogrel

BACKGROUND

Inflammation plays a major role in the pathophysiology of coronary artery disease. We aimed to determine whether baseline inflammatory markers were associated with clinical outcomes and the observed superiority of ticagrelor compared to clopidogrel in patients with acute coronary syndromes in the PLATO study.

METHODS

Blood samples were collected from 16,400 patients within 24 hours of the onset of acute coronary syndrome, at the time of random assignment to ticagrelor or clopidogrel in the PLATO study and prior to invasive procedures. The differential white blood cell count and plasma levels of C-reactive protein, interleukin-6 and interleukin-10 were determined and their relationships with clinical outcomes were assessed according to quartiles and using continuous models. The substudy primary endpoint was a composite of cardiovascular death and myocardial infarction.

RESULTS

Compared to the lowest quartile, the risk of the primary endpoint was significantly elevated in patients in the highest quartile of white blood cell count (hazard ratio (HR) 1.30; P=0.01), neutrophil count (HR 1.33; P=0.007), monocyte count (HR 1.24; P=0.004), C-reactive protein (HR 1.93; P<0.001) and interleukin-6 (HR 2.29; P<0.001). This was predominantly driven by an association with cardiovascular death. Following adjustment for clinical characteristics, troponin, cystatin C and N-terminal pro-brain-type natriuretic peptide, only white blood cell count and neutrophil count maintained a significant association with the primary endpoint. Ticagrelor had a consistent relative cardiovascular benefit compared to clopidogrel in each quartile of each of the inflammatory markers.

CONCLUSIONS

Acute coronary syndrome patients with elevated levels of baseline inflammatory markers are at increased risk of adverse cardiovascular events, particularly cardiovascular death. The consistent cardiovascular benefit of ticagrelor compared to clopidogrel tended to confer a greater absolute risk reduction in patients with the highest levels of inflammatory markers, as they were at highest risk.

Asenapine maleate inhibits angiotensin II-induced proliferation and activation of cardiac fibroblasts via the ROS/TGFβ1/MAPK signaling pathway

BACKGROUND

Cardiac fibrosis will increase wall stiffness and diastolic dysfunction, which will eventually lead to heart failure. Asenapine maleate (AM) is widely used in the treatment of schizophrenia. In the current study, we explored the potential mechanism underlying the role of AM in angiotensin II (Ang II)-induced cardiac fibrosis.

METHODS

Cardiac fibroblasts (CFs) were stimulated using Ang II with or without AM. Cell proliferation was measured using the cell counting kit-8 assay and the Cell-Light EdU Apollo567 In Vitro Kit. The expression levels of proliferating cell nuclear antigen (PCNA) and α-smooth muscle actin (α-SMA) were detected using immunofluorescence or western blotting. At the protein level, the expression levels of the components of the transforming growth factor beta 1 (TGFβ1)/mitogen-activated protein kinase (MAPK) signaling pathway were also detected.

RESULTS

After Ang II stimulation, TGFβ1, TGFβ1 receptor, α-SMA, fibronectin (Fn), collagen type I (Col1), and collagen type III (Col3) mRNA levels increased; the TGFβ1/MAPK signaling pathway was activated in CFs. After AM pretreatment, cell proliferation was inhibited, the numbers of PCNA -positive cells and the levels of cardiac fibrosis markers decreased. The activity of the TGFβ1/MAPK signaling pathway was also inhibited. Therefore, AM can inhibit cardiac fibrosis by blocking the Ang II-induced activation through TGFβ1/MAPK signaling pathway.

CONCLUSIONS

This is the first report to demonstrate that AM can inhibit Ang II-induced cardiac fibrosis by down-regulating the TGFβ1/MAPK signaling pathway. In this process, AM inhibited the proliferation and activation of CFs and reduced the levels of cardiac fibrosis markers. Thus, AM represents a potential treatment strategy for cardiac fibrosis.

The role of interleukin-10 family members in cardiovascular diseases

Interleukin (IL)-10 cytokine family members, including IL-10, IL-19, IL-20, IL-22, IL-24, IL-26 and the distantly related IL-28A, IL-28B, and IL-29, play critical roles in the regulation of inflammation. The occurrence and progression of cardiovascular diseases closely correlate with the regulation of inflammation, which may provide novel strategies for the treatment of cardiovascular diseases. In recent years, studies have focused on the association between the IL-10 cytokine family and the physiological and pathological progression of cardiovascular diseases. The aim of this review is to summarize relevant studies and clarify whether the IL-10 cytokine family contributes to the regulation of cardiovascular diseases.

Silencing p53 inhibits interleukin 10-induced activated hepatic stellate cell senescence and fibrotic degradation in vivo

Activated hepatic stellate cells are reported to play a significant role in liver fibrogenesis. Beside the phenotype reversion and apoptosis of activated hepatic stellate cells, the senescence of activated hepatic stellate cells limits liver fibrosis. Our previous researches have demonstrated that interleukin-10 could promote hepatic stellate cells senescence via p53 signaling pathway in vitro. However, the relationship between expression of p53 and senescence of activated hepatic stellate cells induced by interleukin-10 in fibrotic liver is unclear. The purpose of present study was to explore whether p53 plays a crucial role in the senescence of activated hepatic stellate cells and degradation of collagen mediated by interleukin-10. Hepatic fibrosis animal model was induced by carbon tetrachloride through intraperitoneal injection and transfection of interleukin-10 gene to liver was performed by hydrodynamic-based transfer system. Depletions of p53 in vivo and in vitro were carried out by adenovirus-based short hairpin RNA against p53. Regression of fibrosis was assessed by liver biopsy and collagen staining. Cellular senescence in the liver was observed by senescence-associated beta-galactosidase (SA-β-Gal) staining. Immunohistochemistry, immunofluorescence double staining, and Western blot analysis were used to evaluate the senescent cell and senescence-related protein expression. Our data showed that interleukin-10 gene treatment could lighten hepatic fibrosis induced by carbon tetrachloride and induce the aging of activated hepatic stellate cells accompanied by up-regulating the expression of aging-related proteins. We further demonstrated that depletion of p53 could abrogate up-regulation of interleukin-10 on the expression of senescence-related protein in vivo and vitro. Moreover, p53 knockout in fibrotic mice could block not only the senescence of activated hepatic stellate cells, but also the degradation of fibrosis induced by interleukin-10 gene intervention. Taken together, our results suggested that interleukin-10 gene treatment could attenuate carbon tetrachloride-induced hepatic fibrosis by inducing senescence of activated hepatic stellate cells in vivo, and this induction was closely related to p53 signaling pathway.

Current Status and Potential Therapeutic Strategies for Using Non-coding RNA to Treat Diabetic Cardiomyopathy

Diabetic cardiomyopathy (DMCM) is the leading cause of mortality and morbidity among diabetic patients. DMCM is characterized by an increase in oxidative stress with systemic inflammation that leads to cardiac fibrosis, ultimately causing diastolic and systolic dysfunction. Even though DMCM pathophysiology is well studied, the approach to limit this condition is not met with success. This highlights the need for more knowledge of underlying mechanisms and innovative therapies. In this regard, emerging evidence suggests a potential role of non-coding RNAs (ncRNAs), including micro-RNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs) as novel diagnostics, mechanisms, and therapeutics in the context of DMCM. However, our understanding of ncRNAs’ role in diabetic heart disease is still in its infancy. This review provides a comprehensive update on pre-clinical and clinical studies that might develop therapeutic strategies to limit/prevent DMCM.

YQWY Decoction Improves Myocardial Remodeling via Activating the IL-10/Stat3 Signaling Pathway

Heart failure (HF) has been known as a global health problem, and cardiac remodeling plays an essential role in the development of HF. We hypothesized that YQWY decoction might exert a cardioprotective effect against myocardium inflammation, fibrosis, and apoptosis via activating the interleukin-10 (IL-10)/Stat3 signaling pathway. To test this hypothesis, the HF model in rats was established by pressure overload through the minimally invasive transverse aortic constriction (MTAC). Echocardiography was performed to assess the left ventricular function of rats. Myocardial fibrosis in rats was observed by Masson and Picrosirius red staining, and the degree of myocardial apoptosis was detected via TUNEL staining. In addition, expression levels of IL-10, tumor necrosis factor-α (TNF-α), Stat3 (P-Stat3), P65 (P-P65), CD68, collagen I, TGF-β, CTGF, Bax, Bcl-2, cleaved caspase-3, and PARP in rat serum and myocardium samples were examined by ELISA, western blot, and immunohistochemistry, respectively. YQWY decoction treatment significantly improved left ventricular function in HF rats, especially in those of the high-dose group (LVEF%: 51.29 ± 5.876 vs. 66.02 ± 1.264, P < 0.01;, LVFS%: 27.75 ± 3.757 vs. 37.76 ± 1.137, P < 0.01). Furthermore, YQWY decoction markedly inhibited MTAC-induced myocardial fibrosis as evidenced by downregulated collagen I, TGF-β, and CTGF in myocardium and alleviated apoptosis (downregulated caspase-3 and PARP and increased Bcl-2/Bax ratio in cardiomyocytes). In addition, YQWY decoction decreased the level of the proinflammatory cytokine TNF-α in both circulating blood and myocardium and attenuated infiltration of inflammatory cells in heart tissue from HF rats. Most importantly, YQWY decoction suppressed MTAC-induced NF-κB activation and phosphorylated Stat3 by upregulating IL-10 in rat heart tissues. Our study showed that YQWY decoction could attenuate MTAC-induced myocardial inflammation, fibrosis, apoptosis, and reverse the impairment of cardiac function in rats by activating the IL-10/Stat3 signaling pathway and improving myocardium remodeling. Our findings suggested a therapeutic potential of YQWY decoction in HF.

The cardiac methylome: A hidden layer of RNA modifications to regulate gene expression

Post-transcriptional RNA modification has been observed in all kingdoms of life and more than a hundred different types of RNA modifications decorate the chemical and topological properties of these ribose nucleotides. These RNA modifications can potentially alter the RNA structure and also affect the binding affinity of proteins, thus regulating the mRNA stability as well as translation. Emerging evidence suggest that these modifications are not static, but are dynamic; vary upon different cues and are cell-type or tissue-specific. The cardiac transcriptome is not exceptional to such RNA modifications and is enriched with the abundant base methylation such as N⁶-methyladenosine (m⁶A) and also 2'-O-Methylation (Nm). In this review we will focus on the technologies available to map these modifications and as well as the contribution of these post-transcriptional modifications during various pathological conditions of the heart.

MicroRNA-21 Mediates a Positive Feedback on Angiotensin II-Induced Myofibroblast Transformation

Objective

Post myocardial infarction (MI) fibrosis has been identified as an important factor in the progression of heart failure. Previous studies have revealed that microRNA-21 (miR-21) plays an important role in the pathogenesis of fibrosis. The purpose of this study was to explore the role of miR-21 in post-MI cardiac fibrosis.

Material and Methods

MI was established in wild-type (WT) and miR-21 knockout (KO) mice. Primary mice cardiac fibroblasts (CFs) were isolated from WT and miR-21 KO mice and were treated with angiotensin II (Ang II) or Sprouty1 (Spry1) siRNA. Histological analysis and echocardiography were used to determine the extent of fibrosis and cardiac function.

Results

Compared with WT mice, miR-21 KO mice displayed smaller fibrotic areas and decreased expression of fibrotic markers and inflammatory cytokines. In parallel, Ang II-induced myofibroblasts transformation was partially inhibited upon miR-21 KO in primary CFs. Mechanistically, we found that the expression of Spry1, a previously reported target of miR-21, was markedly increased in miR-21 KO mice post MI, further inhibiting ERK1/2 activation. In vitro studies showed that Ang II activated ERK1/2/TGF-β/Smad2/3 pathway. Phosphorylated Smad2/3 further enhanced the expression of α-SMA and FAP and may promote the maturation of miR-21, thereby downregulating Spry1. Additionally, these effects of miR-21 KO on fibrosis were reversed by siRNA-mediated knockdown of Spry1.

Conclusion

Our findings suggest that miR-21 promotes post-MI fibrosis by targeting Spry1. Furthermore, it mediates a positive feedback on Ang II, thereby inducing the ERK/TGF-β/Smad pathway. Therefore, targeting the miR-21–Spry1 axis may be a promising therapeutic option for ameliorating post-MI cardiac fibrosis.

Cardiac fibrosis

Myocardial fibrosis, the expansion of the cardiac interstitium through deposition of extracellular matrix proteins, is a common pathophysiologic companion of many different myocardial conditions. Fibrosis may reflect activation of reparative or maladaptive processes. Activated fibroblasts and myofibroblasts are the central cellular effectors in cardiac fibrosis, serving as the main source of matrix proteins. Immune cells, vascular cells and cardiomyocytes may also acquire a fibrogenic phenotype under conditions of stress, activating fibroblast populations. Fibrogenic growth factors (such as transforming growth factor-β and platelet-derived growth factors), cytokines [including tumour necrosis factor-α, interleukin (IL)-1, IL-6, IL-10, and IL-4], and neurohumoral pathways trigger fibrogenic signalling cascades through binding to surface receptors, and activation of downstream signalling cascades. In addition, matricellular macromolecules are deposited in the remodelling myocardium and regulate matrix assembly, while modulating signal transduction cascades and protease or growth factor activity. Cardiac fibroblasts can also sense mechanical stress through mechanosensitive receptors, ion channels and integrins, activating intracellular fibrogenic cascades that contribute to fibrosis in response to pressure overload. Although subpopulations of fibroblast-like cells may exert important protective actions in both reparative and interstitial/perivascular fibrosis, ultimately fibrotic changes perturb systolic and diastolic function, and may play an important role in the pathogenesis of arrhythmias. This review article discusses the molecular mechanisms involved in the pathogenesis of cardiac fibrosis in various myocardial diseases, including myocardial infarction, heart failure with reduced or preserved ejection fraction, genetic cardiomyopathies, and diabetic heart disease. Development of fibrosis-targeting therapies for patients with myocardial diseases will require not only understanding of the functional pluralism of cardiac fibroblasts and dissection of the molecular basis for fibrotic remodelling, but also appreciation of the pathophysiologic heterogeneity of fibrosis-associated myocardial disease.

Signaling via the Interleukin-10 Receptor Attenuates Cardiac Hypertrophy in Mice During Pressure Overload, but not Isoproterenol Infusion

Inflammation plays a key role during cardiac hypertrophy and the development of heart failure. Interleukin-10 (IL-10) is a major anti-inflammatory cytokine that is expressed in the heart and may play a crucial role in cardiac remodeling. Based on the evidence that IL-10 potentially reduces pathological hypertrophy, it was hypothesized that signaling via the IL-10 receptor (IL10R) in the heart produces a protective role in reducing cardiac hypertrophy. The aim of this study was to investigate the effects of the ablation of Il-10-r1 gene during pathological cardiac hypertrophy in mice. We found that IL-10R1 gene silencing in cultured cardiomyocytes diminished the anti-hypertrophic effect of Il-10 in TNF-α induced hypertrophy model. We then analyzed mice deficient in the Il-10-r1 gene (IL-10R1^-/- mice) and subjected them to transverse aortic constriction or isoproterenol infusion to induce pathological hypertrophy. In response to transverse aortic constriction for 2 weeks, IL-10R1^-/- mice displayed a significant increase in the hypertrophic response as indicated by heart weight/body weight ratio, which was accompanied by significant increases in cardiomyocyte surface area and interstitial fibrosis. In contrast, there was no difference in hypertrophic response to isoproterenol infusion (10 days) between the knockout and control groups. Analysis of cardiac function using echocardiography and invasive hemodynamic studies did not show any difference between the WT and IL-10R1^-/- groups, most likely due to the short term nature of the models. In conclusion, our data shows that signaling via the IL-10 receptor may produce protective effects against pressure overload-induced hypertrophy but not against β-adrenergic stimuli in the heart. Our data supports previous evidence that signaling modulated by IL-10 and its receptor may become a potential target to control pathological cardiac hypertrophy.

Innate Immunity Effector Cells as Inflammatory Drivers of Cardiac Fibrosis

Despite relevant advances made in therapies for cardiovascular diseases (CVDs), they still represent the first cause of death worldwide. Cardiac fibrosis and excessive extracellular matrix (ECM) remodeling are common end-organ features in diseased hearts, leading to tissue stiffness, impaired myocardial functional, and progression to heart failure. Although fibrosis has been largely recognized to accompany and complicate various CVDs, events and mechanisms driving and governing fibrosis are still not entirely elucidated, and clinical interventions targeting cardiac fibrosis are not yet available. Immune cell types, both from innate and adaptive immunity, are involved not just in the classical response to pathogens, but they take an active part in "sterile" inflammation, in response to ischemia and other forms of injury. In this context, different cell types infiltrate the injured heart and release distinct pro-inflammatory cytokines that initiate the fibrotic response by triggering myofibroblast activation. The complex interplay between immune cells, fibroblasts, and other non-immune/host-derived cells is now considered as the major driving force of cardiac fibrosis. Here, we review and discuss the contribution of inflammatory cells of innate immunity, including neutrophils, macrophages, natural killer cells, eosinophils and mast cells, in modulating the myocardial microenvironment, by orchestrating the fibrogenic process in response to tissue injury. A better understanding of the time frame, sequences of events during immune cells infiltration, and their action in the injured inflammatory heart environment, may provide a rationale to design new and more efficacious therapeutic interventions to reduce cardiac fibrosis.

MFGE8 is down-regulated in cardiac fibrosis and attenuates endothelial-mesenchymal transition through Smad2/3-Snail signalling pathway

Endothelial‐mesenchymal transition (EndMT) is a major source of transformed cardiac fibroblasts, which is reported to play a key role in cardiac fibrosis (CF), a pathogenesis of cardiovascular diseases such as heart failure, myocardial infarction and atrial fibrillation. Nonetheless, the specific mechanism underlying the progression of EndMT to CF is still largely unknown. In this study, we aimed to investigate the role of milk fat globule‐EGF factor 8 (MFGE8), a kind of soluble glycoprotein, in TGF‐β1‐induced EndMT. In animal experiments, the expression of MFGE8 was found down‐regulated in the left ventricle and aorta of rats after transverse aortic constriction (TAC) compared with the sham group, especially in endothelial cells (ECs). In in vitro cultured ECs, silencing MFGE8 with small interfering RNA (siRNA) was found to promote the process of TGF‐β1‐induced EndMT, whereas administration of recombinant human MFGE8 (rh‐MFGE8) attenuated the process. Moreover, activated Smad2/3 signalling pathway after TGF‐β1 treatment and EndMT‐related transcription factors, such as Snail, Twist and Slug, was potentiated by MFGE8 knock‐down but inhibited by rh‐MFGE8. In conclusion, our experiments indicate that MFGE8 might play a protective role in TGF‐β1‐induced EndMT and might be a potential therapeutic target for cardiac fibrosis.

Modulation of cardiac renin-angiotensin system, redox status and inflammatory profile by different volumes of aerobic exercise training in obese rats

Overactivation of the classical arm of the renin-angiotensin (Ang) system (RAS) occurs during inflammation, oxidative stress and obesity-induced cardiomyopathy. The activation of the protective arm of RAS may act to counterbalance the deleterious effects of the classical RAS. Although aerobic exercise training (AET) shifts the balance of the RAS towards the protective arm, little is known about the molecular adaptations to different volumes of AET. The aim of this study was to evaluate the impact of AET volume on the modulation of RAS, as well as on cardiac biomarkers of oxidative stress and inflammation, in a diet-induced obesity model. Male Wistar rats were fed either control (CON) or high fat (HF) diet for 32 weeks. At week 20, HF group was subdivided into sedentary, low (LEV, 150 min/week) or high (HEV, 300 min/week) exercise volume. After 12 weeks of exercise, body mass gain, systolic blood pressure and heart rate were evaluated, as well as RAS, oxidative stress and inflammation in the heart. Body mass gain, systolic blood pressure and heart rate were higher in HF group when compared with SC group. Both trained groups restored systolic blood pressure and heart rate, but only HEV reduced body mass gain. Regarding the cardiac RAS, the HF group exhibited favoring of the classical arm and both trained groups shifted the balance towards the counterregulatory protective arm. The HF group had higher B1R expression and lower B2R expression than the control group, and B2R expression was reverted in both trained groups. The HF group also presented oxidative stress. The LEV and HEV groups improved the cardiac redox status by reducing Nox 2 and nitrotyrosine expression, but only the LEV group was able to increase the antioxidant defense by increasing Nrf2 signaling. While the HF group presented higher TNF-α, IL-6 and NFκB expression, and lower IL-10 expression, than the SC group, both training protocols improved the inflammatory profile. Although both trained groups improved the deleterious changes related to obesity cardiomyopathy, it is clear that the molecular mechanisms differ between them. Our results suggest that different exercise volumes might reach different molecular targets, and this could be a relevant factor when using exercise to manage obesity.

Hepatocyte Growth Factor Secreted from Human Adipose-Derived Stem Cells Inhibits Fibrosis in Hypertrophic Scar Fibroblasts

AIMS

To study the effect of Adipose-derived stem cells (ADSCs) on fibrosis of hypertrophic scar-derived fibroblasts (HSFs) and its concrete mechanism.

BACKGROUND

ADSCs have been reported to reduce collagen production and fibroblast proliferation in co-culture experiments. Conditioned medium from adipose-derived stem cells (ADSCs-CM) has successfully inhibited fibrosis by decreasing the expression of collagen type І (Col1) and α-smooth muscle actin (α-SMA) in rabbit ear scar models. Hepatocyte growth factor (HGF), the primary growth factor in ADSCs-CM, has been shown to reverse fibrosis in various fibrotic diseases.

OBJECTIVE

To test the hypothesis that ADSCs inhibit fibrosis of HSFs through the secretion of HGF.

METHODS

HSFs were treated with DMEM containing 0%, 10%, 50% and 100% concentration of ADSCs-CM. The effect of ADSCs-CM on the viability was determined by cell viability assay, and the collagen production in HSFs was examined by Sirius red staining. Expression and secretion of fibrosis and degradation proteins were detected separately. After measuring the concentration of HGF in ADSCs-CM, the same number of HSFs were treated with 50% ADSCs-CM or HGF. HGF activity in ADSCs-CM was neutralized with a goat anti-human HGF antibody.

RESULTS

The results demonstrated that ADSCs-CM dose-dependently decreased cell viability, expression of fibrosis molecules, and tissue inhibitor of metalloproteinases-1 (TIMP-1), and significantly increased matrix metalloproteinase-1 (MMP-1) expression in HSFs. Collagen production and the ratio of collagen type І and type III (Col1/Col3) were also suppressed by ADSCs-CM in a dose-dependent manner. When HSFs were cultured with either 50% ADSCs-CM or HGF (1 ng/ml), a similar trend was observed in gene expression and protein secretion. Adding an HGF antibody to both groups returned protein expression and secretion to basal levels but did not significantly affect the fibrosis factors in the control group.

CONCLUSION

Our findings revealed that adipose-derived stem cell-secreted HGF effectively inhibits fibrosis-related factors and regulates extracellular matrix (ECM) remodeling in hypertrophic scar fibroblasts.

Cardiac Fibrosis and Cardiac Fibroblast Lineage-Tracing: Recent Advances

Cardiac fibrosis is a common pathological change associated with cardiac injuries and diseases. Even though the accumulation of collagens and other extracellular matrix (ECM) proteins may have some protective effects in certain situations, prolonged fibrosis usually negatively affects cardiac function and often leads to deleterious consequences. While the development of cardiac fibrosis involves several cell types, the major source of ECM proteins is cardiac fibroblast. The high plasticity of cardiac fibroblasts enables them to quickly change their behaviors in response to injury and transition between several differentiation states. However, the study of cardiac fibroblasts in vivo was very difficult due to the lack of specific research tools. The development of cardiac fibroblast lineage-tracing mouse lines has greatly promoted cardiac fibrosis research. In this article, we review the recent cardiac fibroblast lineage-tracing studies exploring the origin of cardiac fibroblasts and their complicated roles in cardiac fibrosis, and briefly discuss the translational potential of basic cardiac fibroblast researches.

Leukocyte-Dependent Regulation of Cardiac Fibrosis

Cardiac fibrosis begins as an intrinsic response to injury or ageing that functions to preserve the tissue from further damage. Fibrosis results from activated cardiac myofibroblasts, which secrete extracellular matrix (ECM) proteins in an effort to replace damaged tissue; however, excessive ECM deposition leads to pathological fibrotic remodeling. At this extent, fibrosis gravely disturbs myocardial compliance, and ultimately leads to adverse outcomes like heart failure with heightened mortality. As such, understanding the complexity behind fibrotic remodeling has been a focal point of cardiac research in recent years. Resident cardiac fibroblasts and activated myofibroblasts have been proven integral to the fibrotic response; however, several findings point to additional cell types that may contribute to the development of pathological fibrosis. For one, leukocytes expand in number after injury and exhibit high plasticity, thus their distinct role(s) in cardiac fibrosis is an ongoing and controversial field of study. This review summarizes current findings, focusing on both direct and indirect leukocyte-mediated mechanisms of fibrosis, which may provide novel targeted strategies against fibrotic remodeling.

Interleukin-10 Deficiency Alters Endothelial Progenitor Cell-Derived Exosome Reparative Effect on Myocardial Repair via Integrin-Linked Kinase Enrichment

Rationale: Systemic inflammation compromises the reparative properties of endothelial progenitor cell (EPC) and their exosomes on myocardial repair, although the underlying mechanism of loss of function of exosomes from inflamed EPCs is still obscure. Objective: To determine the mechanisms of IL-10 (interleukin-10) deficient-EPC-derived exosome dysfunction in myocardial repair and to investigate if modification of specific exosome cargo can rescue reparative activity. Methods and Results: Using IL-10 knockout mice mimicking systemic inflammation condition, we compared therapeutic effect and protein cargo of exosomes isolated from wild-type EPC and IL-10 knockout EPC. In a mouse model of myocardial infarction (MI), wild-type EPC-derived exosome treatment significantly improved left ventricle cardiac function, inhibited cell apoptosis, reduced MI scar size, and promoted post-MI neovascularization, whereas IL-10 knockout EPC-derived exosome treatment showed diminished and opposite effects. Mass spectrometry analysis revealed wild-type EPC-derived exosome and IL-10 knockout EPC-derived exosome contain different protein expression pattern. Among differentially expressed proteins, ILK (integrin-linked kinase) was highly enriched in both IL-10 knockout EPC-derived exosome as well as TNFα (tumor necrosis factor-α)-treated mouse cardiac endothelial cell-derived exosomes (TNFα inflamed mouse cardiac endothelial cell-derived exosome). ILK-enriched exosomes activated NF-κB (nuclear factor κB) pathway and NF-κB-dependent gene transcription in recipient endothelial cells and this effect was partly attenuated through ILK knockdown in exosomes. Intriguingly, ILK knockdown in IL-10 knockout EPC-derived exosome significantly rescued their reparative dysfunction in myocardial repair, improved left ventricle cardiac function, reduced MI scar size, and enhanced post-MI neovascularization in MI mouse model. Conclusions: IL-10 deficiency/inflammation alters EPC-derived exosome function, content and therapeutic effect on myocardial repair by upregulating ILK enrichment in exosomes, and ILK-mediated activation of NF-κB pathway in recipient cells, whereas ILK knockdown in exosomes attenuates NF-κB activation and reduces inflammatory response. Our study provides new understanding of how inflammation may alter stem cell-exosome-mediated cardiac repair and identifies ILK as a target kinase for improving progenitor cell exosome-based cardiac therapies.

Cardiac Fibroblasts and Cardiac Fibrosis: Precise Role of Exosomes

Exosomes are a group of extracellular microvesicles that deliver biologically active RNAs, proteins, lipids and other signaling molecules to recipient cells. Classically, exosomes act as a vehicle by which cells or organs communicate with each other to maintain cellular/tissue homeostasis and to respond to pathological stress. Most multicellular systems, including the cardiovascular system, use exosomes for intercellular communication. In heart, endogenous exosomes from cardiac cells or stem cells aid in regulation of cell survival, cell proliferation and cell death; and thus tightly regulate cardiac biology and repair processes. Pathological stimulus in heart alters secretion and molecular composition of exosomes, thus influencing the above processes. The past decade has yielded increasing interest in the role of exosomes in the cardiovascular system and significant contribution of cardiac fibroblast (CF) and mediated cardiac fibrosis in heart failure, in this review we had overviewed the relevant literatures about fibroblast exosomes, its effect in the cardiovascular biology and its impact on cardiovascular disease (CVD). This review briefly describes the communication between fibroblasts and other cardiac cells via exosomes, the influence of such on myocardial fibrosis and remodeling, and the possibilities to use exosomes as biomarkers for acute and chronic heart diseases.

Curcumin Management of Myocardial Fibrosis and its Mechanisms of Action: A Review

Myocardial fibrosis is implicated as a leading risk factor for heart failure, arrhythmia, and sudden death after cardiac injury, as the excessive interstitial extracellular matrix impedes heart contraction and electrical conduction. Complicated mechanisms involving oxidative stress, pro-inflammatory cytokines, chemokine families, NLRP3 inflammasomes, growth factors, and non-coding RNAs participate in cardiac fibrogenesis and make it difficult to designate specific and effective therapies. Oriental herbs have been popular for thousands of years in the health care of Asian residents, due to their multi-targeted, multi-faceted approaches and their multi-functional effects in fighting difficult and complicated diseases, including cardiovascular disorders such as myocardial fibrosis. Curcumin, a natural polyphenol and yellow pigment obtained from the spice turmeric, was found to have strong anti-oxidant and anti-inflammatory properties. Increasing evidence has shown that curcumin can be used to prevent and treat myocardial fibrosis, when the myocardium suffers pathological pro-fibrotic changes in vivo and in vitro. The present review focuses on recent studies elucidating the mechanisms of curcumin in treating different pathologic conditions, including ischemia, hypoxia/reoxygenation, pressure or volume overload, and hyperglycemia or high-fat-induced cardiac fibrosis. Novel analogs such as C66, B2BrBC, Y20, and J17 have been designed to maximize the therapeutic potentials of curcumin. These optimized curcumin analogs with improved bioavailability and pharmacokinetic profiles need to be clinically verified before curcumin could be recommended for the treatment of myocardial fibrosis.

The Association between Cytokines and 365-Day Readmission or Mortality in Adult Cardiac Surgery

Cardiac surgery results in a multifactorial systemic inflammatory response with inflammatory cytokines, such as interleukin-10 and 6 (IL-10 and IL-6), shown to have potential in the prediction of adverse outcomes including readmission or mortality. This study sought to measure the association between IL-6 and IL-10 levels and 1-year hospital readmission or mortality following cardiac surgery. Plasma biomarkers IL-6 and IL-10 were measured in 1,047 patients discharged alive after isolated coronary artery bypass graft surgery from eight medical centers participating in the Northern New England Cardiovascular Disease Study Group between 2004 and 2007. Readmission status and mortality were ascertained using Medicare, state all-payer claims, and the National Death Index. We evaluated the association between preoperative and postoperative cytokines and 1-year readmission or mortality using Kaplan-Meier estimates and Cox's proportional hazards modeling, adjusting for covariates used in the Society of Thoracic Surgeons 30-day readmission model. The median follow-up time was 1 year. After adjustment, patients in the highest tertile of postoperative IL-6 values had a significantly increased risk of readmission or death within 1 year (HR: 1.38; 95% CI: 1.03-1.85), and an increased risk of death within 1 year of discharge (HR: 4.88; 95% CI: 1.26-18.85) compared with patients in the lowest tertile. However, postoperative IL-10 levels, although increasing through tertiles, were not found to be significantly associated independently with 1-year readmission or mortality (HR: 1.25; 95% CI: .93-1.69). Pro-inflammatory cytokine IL-6 and anti-inflammatory cytokine IL-10 may be postoperative markers of cardiac injury, and IL-6, specifically, shows promise in predicting readmission and mortality following cardiac surgery.

Acetaldehyde dehydrogenase 2 deficiency exacerbates cardiac fibrosis by promoting mobilization and homing of bone marrow fibroblast progenitor cells

Cardiac fibrosis is a common feature of various cardiovascular diseases. Previous studies showed that acetaldehyde dehydrogenase 2 (ALDH2) deficiency exacerbated pressure overload-induced heart failure. However, the role and mechanisms of cardiac fibrosis in this process remain largely unknown. This study aimed to investigate the effect of ALDH2 deficiency on cardiac fibrosis in transverse aortic constriction (TAC) induced pressure overload model in mice. Echocardiography and histological analysis revealed cardiac dysfunction and enhanced cardiac fibrosis in TAC-operated animals; ALDH2 deficiency further aggravated these changes. ALDH2 chimeric mice were generated by bone marrow (BM) transplantation of WT mice into the lethally irradiated ALDH2KO mice. The proportion of circulating fibroblast progenitor cells (FPCs) and ROS level in BM after TAC were significantly higher in ALDH2KO mice than in ALDH2 chimeric mice. Furthermore, FPCs were isolated and cultured for in vitro mechanistic studies. The results showed that the stem cell-derived factor 1 (SDF-1)/C-X-C chemokine receptor 4 (CXCR4) axis played a major role in the recruitment of FPCs. In conclusion, our research reveals that increased bone marrow FPCs mobilization and myocardial homing contribute to the enhanced cardiac fibrosis and dysfunction induced by TAC in ALDH2 KO mice via exacerbating accumulation of ROS in BM and myocardial SDF-1 expression.

Podoplanin neutralization improves cardiac remodeling and function after acute myocardial infarction

Podoplanin, a small mucine-type transmembrane glycoprotein, has been recently shown to be expressed by lymphangiogenic, fibrogenic and mesenchymal progenitor cells in the acutely and chronically infarcted myocardium. Podoplanin binds to CLEC-2, a C-type lectin-like receptor 2 highly expressed by CD11bhigh cells following inflammatory stimuli. Why podoplanin expression appears only after organ injury is currently unknown. Here, we characterize the role of podoplanin in different stages of myocardial repair after infarction and propose a podoplanin-mediated mechanism in the resolution of post-MI inflammatory response and cardiac repair. Neutralization of podoplanin led to significant improvements in the left ventricular functions and scar composition in animals treated with podoplanin neutralizing antibody. The inhibition of the interaction between podoplanin and CLEC-2 expressing immune cells in the heart enhances the cardiac performance, regeneration and angiogenesis post MI. Our data indicates that modulating the interaction between podoplanin positive cells with the immune cells after myocardial infarction positively affects immune cell recruitment and may represent a novel therapeutic target to augment post-MI cardiac repair, regeneration and function.

Heart Inflammation: Immune Cell Roles and Roads to the Heart

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

Use of Growth Factors and Other Cytokines for Treatment of Injuries During a Radiation Public Health Emergency

Due to the threat of a radiological or nuclear incident that could impact citizens, the U.S. Department of Health and Human Services tasked the National Institute of Allergy and Infectious Diseases (NIAID) with identifying and funding early- to mid-stage medical countermeasure (MCM) development to treat radiation-induced injuries. Given that the body's natural response to radiation exposure includes production of growth factors and cytokines, and that the only drugs approved by the U.S. Food and Drug Administration to treat acute radiation syndrome are growth factors targeting either the granulocyte (Neupogen^® or Neulasta^®) or granulocyte and macrophage (Leukine^®) hematopoietic cell lineages, there is interest in understanding the role that these factors play in responding to and/or ameliorating radiation damage. Furthermore, in an environment where resources are scarce, such as what might be expected during a radiation public health emergency, availability of growth factor or other treatments may be limited. For these reasons, the NIAID partnered with the Radiation Injury Treatment Network (RITN), whose membership includes medical centers with expertise in the management of bone marrow failure, to explore the use of growth factors and other cytokines as MCMs to mitigate/treat radiation injuries. A workshop was convened that included government, industry and academic subject matter experts, with presentations covering the anticipated concept of operations during a mass casualty incident including triage and treatment, growth factors under development for a radiation indication, and how the practice of medicine can inform other potential approaches, as well as considerations for administration of these products to diverse civilian populations. This report reviews the information presented, and provides an overview of the discussions from a guided breakout session.

Use of Growth Factors and Cytokines to Treat Injuries Resulting from a Radiation Public Health Emergency

In response to concerns over possible radiological or nuclear incidents, the Radiation and Nuclear Countermeasures Program within the National Institute of Allergy and Infectious Diseases (NIAID) was tasked by the U.S. Department of Health and Human Services to support development of medical countermeasures (MCM) to treat the acute and delayed injuries that can result from radiation exposure. To date, the only three drugs approved by the U.S. Food and Drug Administration for treatment of acute radiation syndrome are growth factors targeting granulocyte (Neupogen^® or Neulasta^®) or granulocyte and macrophage (Leukine^®) hematopoietic cell lineages. Although these are currently stockpiled for deployment in response to a mass casualty scenario, these growth factors will likely be administered in a scarce-resources environment and availability may be limited. Therefore, there is growing interest in understanding the role that these growth factors play in mitigating radiation damage, to optimize their use and maximize the number of people who can be treated. For these reasons, the NIAID and the Radiation Injury Treatment Network organized a workshop to explore the use of growth factors and other cytokines as MCMs in the treatment of radiation-induced injuries. Subject matter experts from government, industry and academia gathered at this workshop to discuss the concept of operations, triage and treatment, administration to diverse civilian populations, growth factors under development for radiation indications, and how the practice of medicine can inform other potential approaches.