Connective Tissue Growth Factor Inhibition Enhances Cardiac Repair and Limits Fibrosis After Myocardial Infarction

YAP dysregulation triggers hypertrophy by CCN2 secretion and TGFβ uptake in human pluripotent stem cell-derived cardiomyocytes

Hypertrophy Cardiomyopathy (HCM) is the most prevalent hereditary cardiovascular disease - affecting >1:500 individuals. Advanced forms of HCM clinically present with hypercontractility, hypertrophy and fibrosis. Several single-point mutations in b-myosin heavy chain (MYH7) have been associated with HCM and increased contractility at the organ level. Different MYH7 mutations have resulted in increased, decreased, or unchanged force production at the molecular level. Yet, how these molecular kinetics link to cell and tissue pathogenesis remains unclear. The Hippo Pathway, specifically its effector molecule YAP, has been demonstrated to be reactivated in pathological hypertrophic growth. We hypothesized that changes in force production (intrinsically or extrinsically) directly alter the homeostatic mechano-signaling of the Hippo pathway through changes in stresses on the nucleus. Using human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs), we asked whether homeostatic mechanical signaling through the canonical growth regulator, YAP, is altered 1) by changes in the biomechanics of HCM mutant cardiomyocytes and 2) by alterations in the mechanical environment. We use genetically edited hiPSC-CM with point mutations in MYH7 associated with HCM, and their matched controls, combined with micropatterned traction force microscopy substrates to confirm the hypercontractile phenotype in MYH7 mutants. We next modulate contractility in healthy and disease hiPSC-CMs by treatment with positive and negative inotropic drugs and demonstrate a correlative relationship between contractility and YAP activity. We further demonstrate the activation of YAP in both HCM mutants and healthy hiPSC-CMs treated with contractility modulators is through enhanced nuclear deformation. We conclude that the overactivation of YAP, possibly initiated and driven by hypercontractility, correlates with excessive CCN2 secretion (connective tissue growth factor), enhancing cardiac fibroblast/myofibroblast transition and production of known hypertrophic signaling molecule TGFβ. Our study suggests YAP being an indirect player in the initiation of hypertrophic growth and fibrosis in HCM. Our results provide new insights into HCM progression and bring forth a testbed for therapeutic options in treating HCM.

Inhibitory effect of microRNA-21 on pathways and mechanisms involved in cardiac fibrosis development

Cardiac fibrosis is a pivotal cardiovascular disease (CVD) process and represents a notable health concern worldwide. While the complex mechanisms underlying CVD have been widely investigated, recent research has highlighted microRNA-21's (miR-21) role in cardiac fibrosis pathogenesis. In this narrative review, we explore the molecular interactions, focusing on the role of miR-21 in contributing to cardiac fibrosis. Various signaling pathways, such as the RAAS, TGF-β, IL-6, IL-1, ERK, PI3K-Akt, and PTEN pathways, besides dysregulation in fibroblast activity, matrix metalloproteinases (MMPs), and tissue inhibitors of MMPs cause cardiac fibrosis. Besides, miR-21 in growth factor secretion, apoptosis, and endothelial-to-mesenchymal transition play crucial roles. miR-21 capacity regulatory function presents promising insights for cardiac fibrosis. Moreover, this review discusses numerous approaches to control miR-21 expression, including antisense oligonucleotides, anti-miR-21 compounds, and Notch signaling modulation, all novel methods of cardiac fibrosis inhibition. In summary, this narrative review aims to assess the molecular mechanisms of cardiac fibrosis and its essential miR-21 function.

A first-in-human phase I study of SHR-1906, a humanized monoclonal antibody against connective tissue growth factor, in healthy participants

New therapeutic targets and drugs are urgently needed to halt the fibrosing process in idiopathic pulmonary fibrosis (IPF). SHR-1906 is a novel fully humanized monoclonal antibody against the connective tissue growth factor, which plays an essential role in the genesis of IPF. We assessed the safety, tolerability, pharmacokinetics (PKs), and immunogenicity of single dose SHR-1906 in healthy participants. This was a randomized, double-blind, placebo-controlled, dose-escalation, phase I study. Twelve healthy participants for each dose level were enrolled to receive single ascending doses of SHR-1906 intravenously (1.5, 6, 12, 20, 30, and 45 mg/kg) or placebo and followed for 71 days. The primary end points were safety and tolerability. Treatment-related treatment-emergent adverse events occurred in 25 participants (46.3%) in the SHR-1906 group and 11 (61.1%) in the placebo group. No serious adverse events occurred. Over the dose range investigated, the geometric mean clearance was 0.14-0.63 mL/h/kg, the geometric mean volume of distribution at steady-state was 47.4-75.5 mL/kg, and the terminal elimination half-life was 51.9-349 h. SHR-1906 showed nonlinear PKs. The peak concentration increased in a dose-proportional manner, whereas the area under the concentration-time curve showed a greater than dose-proportional increase. Anti-drug antibodies of SHR-1906 were detected in nine of 54 participants (16.7%). A single dose of SHR-1906 up to 45 mg/kg demonstrated a favorable tolerability profile in healthy participants. The PKs and immunogenicity of SHR-1906 were evaluated, supporting further clinical development.

CHI3L1 promotes myocardial fibrosis via regulating lncRNA TUG1/miR-495-3p/ETS1 axis

Abnormal levels of CHI3L1 and lnc TUG1 are often associated with myocardial fibrosis, and their specific expressions may be closely related to the process of myocardial fibrosis. In addition, CHI3L1 was found to significantly up-regulate the expression of lncTUG1. Therefore, this study further explored the major role of CHI3L1 in regulating the progression of myocardial fibrosis. Myocardial fibrosis in mice was established using an angiotensin (Ang II) model, and the degree of myocardial fibrosis was assessed by qPCR, western blot and pathological techniques. HL-1 cells with overexpression and silencing of CHI3L1 were constructed, and the cell migration ability was detected using the Transwell method. Biological information was used to predict the potential target miRNA of lnc TUG1, and the interaction between them was verified by dual luciferase reporter assay. Using functional rescue assay and the rAAV9 technique, CHI3L1 was verified to affect the fibrotic process of myocardial cells by regulating the lnc TUG1/miR-495-3p/ETS1 axis in vitro and in vivo. The myocardial fibrosis index in the model group was significantly upregulated, and expression of both CHI3L1 and lnc TUG1 was upregulated. Pathological results revealed fibrosis and collagen deposition in the myocardium. Overexpression of lnc TUG1 reversed the inhibitory effect of CHI3L1 silencing on myocardial fibrosis. Mechanistically, CH3L1 upregulates the expression of lnc TUG1, and lnc TUG1 weakens the inhibition of ETS1 through sponge absorption of miR-495-3p, promoting the process of myocardial fibrosis.

mRNA sequencing reveals the distinct gene expression and biological functions in cardiac fibroblasts regulated by recombinant fibroblast growth factor 2

After myocardial injury, cardiac fibroblasts (CFs) differentiate into myofibroblasts, which express and secrete extracellular matrix (ECM) components for myocardial repair, but also promote myocardial fibrosis. Recombinant fibroblast growth factor 2 (FGF2) protein drug with low molecular weight can promote cell survival and angiogenesis, and it was found that FGF2 could inhibit the activation of CFs, suggesting FGF2 has great potential in myocardial repair. However, the regulatory role of FGF2 on CFs has not been fully elucidated. Here, we found that recombinant FGF2 significantly suppressed the expression of alpha smooth muscle actin (α-SMA) in CFs. Through RNA sequencing, we analyzed mRNA expression in CFs and the differently expressed genes regulated by FGF2, including 430 up-regulated genes and 391 down-regulated genes. Gene ontology analysis revealed that the differentially expressed genes were strongly enriched in multiple biological functions, including ECM organization, cell adhesion, actin filament organization and axon guidance. The results of gene set enrichment analysis (GSEA) show that ECM organization and actin filament organization are down-regulated, while axon guidance is up-regulated. Further cellular experiments indicate that the regulatory functions of FGF2 are consistent with the findings of the gene enrichment analysis. This study provides valuable insights into the potential therapeutic role of FGF2 in treating cardiac fibrosis and establishes a foundation for further research to uncover the underlying mechanisms of CFs gene expression regulated by FGF2.

Pamrevlumab, a Fully Human Monoclonal Antibody Targeting Connective Tissue Growth Factor, for Non-Ambulatory Patients with Duchenne Muscular Dystrophy

BACKGROUND

Duchenne muscular dystrophy (DMD) is a neuromuscular disease stemming from dystrophin gene mutations. Lack of dystrophin leads to progressive muscle damage and replacement of muscle with fibrotic and adipose tissue. Pamrevlumab (FG-3019), a fully human monoclonal antibody that binds to connective tissue growth factor (CTGF), is in Phase III development for treatment of DMD and other diseases.

METHODS

MISSION (Study 079; NCT02606136) was an open-label, Phase II, single-arm trial of pamrevlumab in 21 non-ambulatory patients with DMD (aged≥12 years, receiving corticosteroids) who received 35-mg/kg intravenous infusions every 2 weeks for 2 years. The primary endpoint was change from baseline in percent predicted forced vital capacity (ppFVC). Secondary endpoints included other pulmonary function tests, upper limb function and strength assessments, and changes in upper arm fat and fibrosis scores on magnetic resonance imaging.

RESULTS

Fifteen patients completed the trial. Annual change from baseline (SE) in ppFVC was -4.2 (0.7) (95% CI -5.5, -2.8). Rate of decline in ppFVC in pamrevlumab-treated patients was slower than observed in historical published trials of non-ambulatory patients. MISSION participants experienced slower-than-anticipated muscle function declines compared with natural history and historical published trials of non-ambulatory patients with DMD. Pamrevlumab was well-tolerated. Treatment-emergent adverse events were mild to moderate, and none led to study discontinuation.

CONCLUSIONS

nti-CTGF therapy with pamrevlumab represents a potential treatment for DMD. The lack of internal control group limits the results.

Extracellular Targets to Reduce Excessive Scarring in Response to Tissue Injury

Excessive scar formation is a hallmark of localized and systemic fibrotic disorders. Despite extensive studies to define valid anti-fibrotic targets and develop effective therapeutics, progressive fibrosis remains a significant medical problem. Regardless of the injury type or location of wounded tissue, excessive production and accumulation of collagen-rich extracellular matrix is the common denominator of all fibrotic disorders. A long-standing dogma was that anti-fibrotic approaches should focus on overall intracellular processes that drive fibrotic scarring. Because of the poor outcomes of these approaches, scientific efforts now focus on regulating the extracellular components of fibrotic tissues. Crucial extracellular players include cellular receptors of matrix components, macromolecules that form the matrix architecture, auxiliary proteins that facilitate the formation of stiff scar tissue, matricellular proteins, and extracellular vesicles that modulate matrix homeostasis. This review summarizes studies targeting the extracellular aspects of fibrotic tissue synthesis, presents the rationale for these studies, and discusses the progress and limitations of current extracellular approaches to limit fibrotic healing.

MicroRNA-19 upregulation attenuates cardiac fibrosis via targeting connective tissue growth factor

BACKGROUND

Previous studies have shown the role of microRNA (miR)-19 in aging-related heart failure. The present study aimed to verify the effects of miR-19 on cardiac fibrosis and its target.

METHODS

Cardiac fibrosis was induced by myocardial infarction (MI)-induced heart failure and angiotensin (Ang) II-treated rats in vivo, and was induced in Ang II-treated cardiac fibroblasts (CFs) in vitro.

RESULTS

The expression of miR-19 was reduced in the heart tissue of MI and Ang II-treated rats, and Ang II-treated CFs. The impaired cardiac function in rats was repaired after miR-19 administration. The levels of collagen I, collagen III and transforming growth factor-beta (TGF-β) increased in the heart tissue of MI and Ang II-treated rats, and Ang II-treated CFs. These increases were reversed by miR-19 agomiR. Moreover, the bioinformatic analysis and luciferase reporter assays demonstrated that connective tissue growth factor (CTGF) was a direct target of miR-19. MiR-19 treatment inhibited CTGF expression in CFs, while CTGF overexpression inhibited miR-19 agomiR to attenuate the Ang II-induced increases of collagen I and collagen III in CFs. The increases of p-ERK, p-JNK and p-p38 in the CFs induced by Ang II were repressed by miR-19 agomiR.

CONCLUSIONS

Upregulating miR-19 can improve cardiac function and attenuate cardiac fibrosis by inhibiting the CTGF and MAPK pathways.

Transcriptome and proteome profiling of activated cardiac fibroblasts supports target prioritization in cardiac fibrosis

BACKGROUND

Activated cardiac fibroblasts (CF) play a central role in cardiac fibrosis, a condition associated with most cardiovascular diseases. Conversion of quiescent into activated CF sustains heart integrity upon injury. However, permanence of CF in active state inflicts deleterious heart function effects. Mechanisms underlying this cell state conversion are still not fully disclosed, contributing to a limited target space and lack of effective anti-fibrotic therapies.

MATERIALS AND METHODS

To prioritize targets for drug development, we studied CF remodeling upon activation at transcriptomic and proteomic levels, using three different cell sources: primary adult CF (aHCF), primary fetal CF (fHCF), and induced pluripotent stem cells derived CF (hiPSC-CF).

RESULTS

All cell sources showed a convergent response upon activation, with clear morphological and molecular remodeling associated with cell-cell and cell-matrix interactions. Quantitative proteomic analysis identified known cardiac fibrosis markers, such as FN1, CCN2, and Serpine1, but also revealed targets not previously associated with this condition, including MRC2, IGFBP7, and NT5DC2.

CONCLUSION

Exploring such targets to modulate CF phenotype represents a valuable opportunity for development of anti-fibrotic therapies. Also, we demonstrate that hiPSC-CF is a suitable cell source for preclinical research, displaying significantly lower basal activation level relative to primary cells, while being able to elicit a convergent response upon stimuli.

mRNA therapy for myocardial infarction: A review of targets and delivery vehicles

Cardiovascular diseases are the leading cause of death in the world. This is partly due to the low regenerative capacity of adult hearts. mRNA therapy is a promising approach under development for cardiac diseases. In mRNA therapy, expression of the target protein is modulated by delivering synthetic mRNA. mRNA therapy benefits cardiac regeneration by increasing cardiomyocyte proliferation, reducing fibrosis, and promoting angiogenesis. Because mRNA is translated in the cytoplasm, the delivery efficiency of mRNA into the cytoplasm and nucleus significantly affects its therapeutic efficacy. To improve delivery efficiency, non-viral vehicles such as lipid nanoparticles have been developed. Non-viral vehicles can protect mRNA from enzymatic degradation and facilitate the cellular internalization of mRNA. In addition to non-viral vehicles, viral vectors have been designed to deliver mRNA templates into cardiac cells. This article reviews lipid nanoparticles, polymer nanoparticles, and viral vectors that have been utilized to deliver mRNA into the heart. Because of the growing interest in lipid nanoparticles, recent advances in lipid nanoparticles designed for cardiac mRNA delivery are discussed. Besides, potential targets of mRNA therapy for myocardial infarction are discussed. Gene therapies that have been investigated in patients with cardiac diseases are analyzed. Reviewing mRNA therapy from a clinically relevant perspective can reveal needs for future investigations.

The emerging role of leptin in obesity-associated cardiac fibrosis: evidence and mechanism

Cardiac fibrosis is a hallmark of various cardiovascular diseases, which is quite commonly found in obesity, and may contribute to the increased incidence of heart failure arrhythmias, and sudden cardiac death in obese populations. As an endogenous regulator of adiposity metabolism, body mass, and energy balance, obesity, characterized by increased circulating levels of the adipocyte-derived hormone leptin, is a critical contributor to the pathogenesis of cardiac fibrosis. Although there are some gaps in our knowledge linking leptin and cardiac fibrosis, this review will focus on the interplay between leptin and major effectors involved in the pathogenesis underlying cardiac fibrosis at both cellular and molecular levels based on the current reports. The profibrotic effect of leptin is predominantly mediated by activated cardiac fibroblasts but may also involve cardiomyocytes, endothelial cells, and immune cells. Moreover, a series of molecular signals with a known profibrotic property is closely involved in leptin-induced fibrotic events. A more comprehensive understanding of the underlying mechanisms through which leptin contributes to the pathogenesis of cardiac fibrosis may open up a new avenue for the rapid emergence of a novel therapy for preventing or even reversing obesity-associated cardiac fibrosis.

Wnt11 in regulation of physiological and pathological cardiac growth

Wnt11 regulates early cardiac development and left ventricular compaction in the heart, but it is not known how Wnt11 regulates postnatal cardiac maturation and response to cardiac stress in the adult heart. We studied cell proliferation/maturation in postnatal and adolescent Wnt11 deficient (Wnt11-/-) heart and subjected adult mice with partial (Wnt11+/-) and complete Wnt11 (Wnt11-/-) deficiency to cardiac pressure overload. In addition, we subjected primary cardiomyocytes to recombinant Wnt proteins to study their effect on cardiomyocyte growth. Wnt11 deficiency did not affect cardiomyocyte proliferation or maturation in the postnatal or adolescent heart. However, Wnt11 deficiency led to enlarged heart phenotype that was not accompanied by significant hypertrophy of individual cardiomyocytes. Analysis of stressed adult hearts from wild-type mice showed a progressive decrease in Wnt11 expression in response to pressure overload. When studied in experimental cardiac pressure overload, Wnt11 deficiency did not exacerbate cardiac hypertrophy or remodeling and cardiac function remained identical between the genotypes. When subjecting cardiomyocytes to hypertrophic stimulus, the presence of recombinant Wnt11 together with Wnt5a reduced protein synthesis. In conclusion, Wnt11 deficiency does not affect postnatal cardiomyocyte proliferation but leads to cardiac growth. Interestingly, Wnt11 deficiency alone does not substantially modulate hypertrophic response to pressure overload in vivo. Wnt11 may require cooperation with other noncanonical Wnt proteins to regulate hypertrophic response under stress.

Novel Therapies for the Treatment of Cardiac Fibrosis Following Myocardial Infarction

Cardiac fibrosis is a common pathological consequence of most myocardial diseases. It is associated with the excessive accumulation of extracellular matrix proteins as well as fibroblast differentiation into myofibroblasts in the cardiac interstitium. This structural remodeling often results in myocardial dysfunctions such as arrhythmias and impaired systolic function in patients with heart conditions, ultimately leading to heart failure and death. An understanding of the precise mechanisms of cardiac fibrosis is still limited due to the numerous signaling pathways, cells, and mediators involved in the process. This review article will focus on the pathophysiological processes associated with the development of cardiac fibrosis. In addition, it will summarize the novel strategies for anti-fibrotic therapies such as epigenetic modifications, miRNAs, and CRISPR technologies as well as various medications in cellular and animal models.

HMOX1 silencing prevents doxorubicin-induced cardiomyocyte injury, mitochondrial dysfunction, and ferroptosis by downregulating CTGF

OBJECTIVES

Doxorubicin is a type of effective antitumor drug but can contribute to cardiomyocyte injuries. We aimed to dissect the mechanism of the HMOX1/CTGF axis in DOX-induced cardiomyocyte injury, mitochondrial dysfunction, and ferroptosis.

METHODS

Bioinformatics analysis was conducted to retrieve differentially expressed genes in a DOX-induced mouse model. Mouse cardiomyocytes, HL-1 cells, were induced with l µM DOX, after which gain- or loss-of-function assays were applied. CCK-8, fluorescent probe assay, flow cytometry, and corresponding kits were employed to detect cell viability, ROS levels, mitochondrial membrane potential and cell apoptosis, and GSH and Fe²⁺ contents, respectively. qRT-PCR or Western blot assay was adopted to test HMOX1, CTGF, BCL-2, Caspase3, Cleaved-Caspase3, and GPX4 expression.

RESULTS

Bioinformatics analysis showed that HMOX1 and CTGF were highly expressed in DOX-induced mice and correlated with each other. Also, HMOX1 and CTGF expression was high in HL-1 cells after DOX treatment, along with an obvious decrease in cell viability and GSH and GPX4 expression, an increase in ROS levels, apoptosis, and Fe²⁺ contents, and mitochondrial membrane potential dysfunction or loss. HMOX1 or CTGF silencing diminished cell apoptosis, Cleaved-Caspase3 expression, Fe²⁺ contents, and ROS levels, enhanced cell viability and the expression of GSH, GPX4, and BCL-2, and recovered mitochondrial membrane potential in DOX-induced HL-1 cells. Nevertheless, the effects of HMOX1 silencing on the viability, apoptosis, ferroptosis, and mitochondrial dysfunction of DOX-induced HL-1 cells were counteracted by CTGF overexpression.

CONCLUSIONS

In conclusion, HMOX1 silencing decreased CTGF expression to alleviate DOX-induced injury, mitochondrial dysfunction, and ferroptosis of mouse cardiomyocytes.

Ginsenoside Rd Promotes Cardiac Repair After Myocardial Infarction by Modulating Monocytes/Macrophages Subsets Conversion

Purpose

This study aimed to elucidate the potential molecular mechanisms by which GSRd improves cardiac inflammation and immune environment after MI.

Materials and Methods

The potential target genes of GSRd were predicted using the STITCH database. In vivo, MI mice models were established by left anterior descending ligation and were divided into the sham group, MI + Vehicle group, and MI + GSRd group. DMSO, DMSO, and GSRd 50 μL/day were intraperitoneally injected, respectively. After 28 days, echocardiography, Masson staining, immunofluorescence staining, flow cytometry, RT-PCR, and Western blot were performed. Mice peritoneal macrophages were extracted in vitro, and Western blot was performed after GSRd and/or Akt inhibitor MK2206 intervention.

Results

GSRd significantly improved mouse myocardial function, attenuated cardiac fibrosis, and inhibited inflammation and apoptosis in myocardial tissues after myocardial infarction. Meanwhile, GSRd increased non-classical Ly6C^low Mos/Mps while reduced of classical Ly6C^high Mos/Mps at the same time in myocardial tissues. In addition, GSRd significantly reversed the activity of p-Akt and p-mTOR in the heart Mos/Mps after MI. In vitro studies showed that the activity of p-Akt and p-mTOR in peritoneal macrophages were significantly increased in a dose-dependent manner after GSRd treatment. Furthermore, the AKT inhibitor MK2206 was found to block the enhanced activity of p-Akt and p-mTOR induced by GSRd in peritoneal macrophages.

Conclusion

GSRd can enhance the transformation of Ly6C^high Mos/Mps to Ly6C^low Mos/Mps in mice after MI by activating the Akt/mTOR signaling pathway, inhibiting cardiac dysfunction and promoting cardiac repair.

Targeting Myocardial Fibrosis—A Magic Pill in Cardiovascular Medicine?

Fibrosis, characterized by an excessive accumulation of extracellular matrix, has long been seen as an adaptive process that contributes to tissue healing and regeneration. More recently, however, cardiac fibrosis has been shown to be a central element in many cardiovascular diseases (CVDs), contributing to the alteration of cardiac electrical and mechanical functions in a wide range of clinical settings. This paper aims to provide a comprehensive review of cardiac fibrosis, with a focus on the main pathophysiological pathways involved in its onset and progression, its role in various cardiovascular conditions, and on the potential of currently available and emerging therapeutic strategies to counteract the development and/or progression of fibrosis in CVDs. We also emphasize a number of questions that remain to be answered, and we identify hotspots for future research.

Cardiac Remodeling in the Absence of Cardiac Contractile Dysfunction Is Sufficient to Promote Cancer Progression

Cardiovascular diseases and cancer are the leading cause of death worldwide. The two diseases share high co-prevalence and affect each other’s outcomes. Recent studies suggest that heart failure promotes cancer progression, although the question of whether cardiac remodeling in the absence of cardiac contractile dysfunction promotes cancer progression remains unanswered. Here, we aimed to examine whether mild cardiac remodeling can promote tumor growth. We used low-phenylephrine (PE)-dose-infused in mice, together with breast cancer cells (polyoma middle T, PyMT), implanted in the mammary fat pad. Although cardiac remodeling, hypertrophy and fibrosis gene hallmarks were identified, echocardiography indicated no apparent loss of cardiac function. Nevertheless, in PE-infused mouse models, PyMT-cell-derived tumors grew larger and displayed increased cell proliferation. Consistently, serum derived from PE-infused mice resulted in increased cancer cell proliferation in vitro. ELISA and gene expression analysis identified periostin, fibronectin and CTGF as cardiac- and tumor-secreted factors that are highly abundant in PE-infused mice serum as compared with non-infused mice. Collectively, a low dose of PE infusion without the deterioration of cardiac function is sufficient to promote cancer progression. Hence, early detection and treatment of hypertension in healthy and cancer patients would be beneficial for improved outcomes.

Genome-wide chromatin contacts of super-enhancer-associated lncRNA identify LINC01013 as a regulator of fibrosis in the aortic valve

Calcific aortic valve disease (CAVD) is characterized by a fibrocalcific process. The regulatory mechanisms that drive the fibrotic response in the aortic valve (AV) are poorly understood. Long noncoding RNAs derived from super-enhancers (lncRNA-SE) control gene expression and cell fate. Herein, multidimensional profiling including chromatin immunoprecipitation and sequencing, transposase-accessible chromatin sequencing, genome-wide 3D chromatin contacts of enhancer-promoter identified LINC01013 as an overexpressed lncRNA-SE during CAVD. LINC01013 is within a loop anchor, which has contact with the promoter of CCN2 (CTGF) located at ~180 kb upstream. Investigation showed that LINC01013 acts as a decoy factor for the negative transcription elongation factor E (NELF-E), whereby it controls the expression of CCN2. LINC01013-CCN2 is part of a transforming growth factor beta 1 (TGFB1) network and exerts a control over fibrogenesis. These findings illustrate a novel mechanism whereby a dysregulated lncRNA-SE controls, through a looping process, the expression of CCN2 and fibrogenesis of the AV.

Calcific aortic valve disease is the most common heart valve disorder characterized by a thickening of the aortic valve resulting from fibrotic and calcific processes. Because the aortic valve replacement is currently the only therapeutic option, the identification of key molecular processes that control the progression of the disease could lead to the development of novel noninvasive therapies. Growing evidence suggests that long noncoding RNAs (lncRNAs) fine tune gene expression in health and disease states. By using a multidimensional profiling including genome-wide 3D enhancer-promoter looping data, we identified LINC01013, a lncRNA, as a regulator of fibrogenesis. Specifically, we found that LINC01013 is located in a cluster of distant enhancers (super-enhancer) in aortic valve interstitial cells and has significant long-range looping with the promoter of CCN2, a gene that orchestrates fibrogenesis. We discovered that LINC01013 is acting as a decoy factor for a negative transcription elongation factor, whereby it controls the transcription of CCN2. In turn, higher expression of LINC01013 during calcific aortic valve disease promoted the expression of CCN2 and a fibrogenic program. These findings provide evidence that LINC01013 is a key regulator of fibrogenesis in CAVD.

Cellular and Molecular Mechanism of Traditional Chinese Medicine on Ventricular Remodeling

Ventricular remodeling is related to the renin-angiotensin-aldosterone system, immune system, and various cytokines involved in inflammation, apoptosis, and cell signal regulation. Accumulated studies have shown that traditional Chinese medicine can significantly inhibit the process of ventricular remodeling, which may be related to the mechanism mentioned above. Here, we conducted a system overview to critically review the cellular and molecular mechanism of traditional Chinese medicine on ventricular remodeling. We mainly searched PubMed for basic research about the anti-ventricular remodeling of traditional Chinese medicine in 5 recent years, and then objectively summarized these researches. We included more than 25 kinds of Chinese herbal medicines including Qi-Li-Qian-Xin, Qi-Shen-Yi-Qi Pill, Xin-Ji-Er-Kang Formula, and Yi-Qi-Wen-Yang Decoction, and found that they can inhibit ventricular remodeling effectively through multi-components and multi-action targets, which are promoting the clinical application of traditional Chinese medicine.

The molecular mechanisms underlying arecoline-induced cardiac fibrosis in rats

The areca nut is one of the most commonly consumed psychoactive substances worldwide, with an estimated consumption by approximately 10% of the world’s population, especially in some regions of South Asia, East Africa, and the tropical Pacific. Arecoline, the major areca nut alkaloid, has been classified as carcinogenic to humans as it adversely affects various organs, including the brain, heart, lungs, gastrointestinal tract, and reproductive organs. Earlier studies have established a link between areca nut chewing and cardiac arrhythmias, and yet research pertaining to the mechanisms underlying cardiotoxicity caused by arecoline is still preliminary. The main purpose of this study is to test the hypothesis that arecoline causes cardiac fibrosis through transforming growth factor-β (TGF-β)/Smad-mediated signaling pathways. Male Wistar rats were injected intraperitoneally with low (5 mg/kg/day) or high (50 mg/kg/day) doses of arecoline for 3 weeks. Results from Masson’s trichrome staining indicated that arecoline could induce cardiac fibrosis through collagen accumulation. Western blot analysis showed that TGF-β and p-Smad2/3 protein expression levels were markedly higher in the arecoline-injected rat hearts than in those of the control rats. Moreover, arecoline upregulated other fibrotic-related proteins, including SP1-mediated connective tissue growth factor expression. Tissue-type plasminogen activator and its inhibitor, plasminogen activator inhibitor, and matrix metalloproteinase (MMP) 9 were upregulated, and the inhibitor of MMP9 was downregulated. This study provides novel insight into the molecular mechanisms underlying arecoline-induced cardiac fibrosis. Taken together, the areca nut is a harmful substance, and the detrimental effects of arecoline on the heart are similar to that caused by oral submucous fibrosis.

Communication Between Cardiomyocytes and Fibroblasts During Cardiac Ischemia/Reperfusion and Remodeling: Roles of TGF-β, CTGF, the Renin Angiotensin Axis, and Non-coding RNA Molecules

Communication between cells is a foundational concept for understanding the physiology and pathology of biological systems. Paracrine/autocrine signaling, direct cell-to-cell interplay, and extracellular matrix interactions are three types of cell communication that regulate responses to different stimuli. In the heart, cardiomyocytes, fibroblasts, and endothelial cells interact to form the cardiac tissue. Under pathological conditions, such as myocardial infarction, humoral factors released by these cells may induce tissue damage or protection, depending on the type and concentration of molecules secreted. Cardiac remodeling is also mediated by the factors secreted by cardiomyocytes and fibroblasts that are involved in the extensive reciprocal interactions between these cells. Identifying the molecules and cellular signal pathways implicated in these processes will be crucial for creating effective tissue-preserving treatments during or after reperfusion. Numerous therapies to protect cardiac tissue from reperfusion-induced injury have been explored, and ample pre-clinical research has attempted to identify drugs or techniques to mitigate cardiac damage. However, despite great success in animal models, it has not been possible to completely translate these cardioprotective effects to human applications. This review provides a current summary of the principal molecules, pathways, and mechanisms underlying cardiomyocyte and cardiac fibroblast crosstalk during ischemia/reperfusion injury. We also discuss pre-clinical molecules proposed as treatments for myocardial infarction and provide a clinical perspective on these potential therapeutic agents.

Preclinical models of myocardial infarction: from mechanism to translation

Approximately 7 million people are affected by acute myocardial infarction (MI) each year, and despite significant therapeutic and diagnostic advancements, MI remains a leading cause of mortality worldwide. Preclinical animal models have significantly advanced our understanding of MI and have enabled the development of therapeutic strategies to combat this debilitating disease. Notably, some drugs currently used to treat MI and heart failure (HF) in patients had initially been studied in preclinical animal models. Despite this, preclinical models are limited in their ability to fully reproduce the complexity of MI in humans. The preclinical model must be carefully selected to maximise the translational potential of experimental findings. This review describes current experimental models of MI and considers how they have been used to understand drug mechanisms of action and support translational medicine development.

Role of Matricellular CCN Proteins in Skeletal Muscle: Focus on CCN2/CTGF and Its Regulation by Vasoactive Peptides

The Cellular Communication Network (CCN) family of matricellular proteins comprises six proteins that share conserved structural features and play numerous biological roles. These proteins can interact with several receptors or soluble proteins, regulating cell signaling pathways in various tissues under physiological and pathological conditions. In the skeletal muscle of mammals, most of the six CCN family members are expressed during embryonic development or in adulthood. Their roles during the adult stage are related to the regulation of muscle mass and regeneration, maintaining vascularization, and the modulation of skeletal muscle fibrosis. This work reviews the CCNs proteins' role in skeletal muscle physiology and disease, focusing on skeletal muscle fibrosis and its regulation by Connective Tissue Growth factor (CCN2/CTGF). Furthermore, we review evidence on the modulation of fibrosis and CCN2/CTGF by the renin-angiotensin system and the kallikrein-kinin system of vasoactive peptides.

Cardiac contractility modulation attenuates structural and electrical remodeling in a chronic heart failure rabbit model

Background

Cardiac contractility modulation (CCM) is non-excitatory electrical stimulation for improving cardiac function. This study aimed to evaluate the effects of CCM on structural and electrical remodeling in a rabbit model of chronic heart failure (CHF).

Methods

Thirty rabbits were randomly divided into the sham, CHF, and CCM groups. The CHF model was induced 12 weeks after trans-aortic constriction by pressure unloading and CCM was delivered to the myocardium for 4 weeks. Corrected QT intervals, the ventricular effective refractory period, and inducibility of ventricular tachycardia were measured by an electrophysiological examination. Connective tissue growth factor, galectin-3, Kv4.3, KCNQ1, KCNH2, and connexin 43 protein levels were measured by western blotting.

Results

The CHF group had a significantly prolonged corrected QT interval and ventricular effective refractory period, and increased inducibility of ventricular tachycardia. Prominent myocardial fibrosis and increased hydroxyproline content were observed in the CHF group, but these were suppressed in the CCM group. Kv4.3, KCNQ1, KCNH2, and connexin 43 protein levels were significantly lower in the CHF group, but treatment with CCM partially restored their levels.

Conclusions

CCM attenuates myocardial structural and electrical remodeling during CHF. These findings provide evidence for clinical use of CCM in treating CHF.

Gene Expression Changes of Humans with Primary Mitral Regurgitation and Reduced Left Ventricular Ejection Fraction

Patients with primary mitral regurgitation (MR) may remain asymptomatic for many years. For unknown reasons, some shift from a compensated to a decompensated state and progress to fatal heart failure. To elucidate the genetic determinants of this process, we recruited 28 patients who underwent mitral valve surgery and stratified them into control, compensated MR, and decompensated MR groups. Tissue biopsies were obtained from the patients’ left ventricular (LV) lateral wall for a transcriptome-wide profiling of 64,769 probes to identify differentially expressed genes (DEGs). Using cutoff values at the 1% FDR significance level and sex- and age-adjusted regression models, we identified 12 significant DEGs (CTGF, MAP1B, SERPINE1, MYH9, MICAL2, MYO1D, CRY1, AQP7P3, HTRA1, PRSS23, IGFBP2, and FN1). The most significant gene was CTGF (adjusted R² = 0.74, p = 1.80 × 10⁻⁸). We found that the majority of genes expressed in the more advanced decompensated MR group were pro-fibrotic genes associated with cardiac fibrosis. In particular, six pro-fibrotic genes (CTGF, SERPINE1, MYH9, HTRA1, PRSS23, and FN1) were overexpressed and enriched in pathways involved in ECM (extracellular matrix) protein remodeling. Therapeutic interventions that antagonize these six genes may slow the progression toward decompensated MR.

FoxO1 is required for high glucose-dependent cardiac fibroblasts into myofibroblast phenoconversion

In the normal heart, cardiac fibroblasts (CFs) maintain extracellular matrix (ECM) homeostasis, whereas in pathological conditions, such as diabetes mellitus (DM), CFs converse into cardiac myofibroblasts (CMFs) and this CFs phenoconversion increase the synthesis and secretion of ECM proteins, promoting cardiac fibrosis and heart dysfunction. High glucose (HG) conditions increase TGF-β1 expression and FoxO1 activity, whereas FoxO1 is crucial to CFs phenoconversion induced by TGF-β1. In addition, FoxO1 increases CTGF expression, whereas CTGF plays an active role in the fibrotic process induced by hyperglycemia. However, the role of FoxO1 and CTGF in CFs phenoconversion induced by HG is not clear. In this study, we investigated the effects of FoxO1 pharmacological inhibition on CFs phenoconversion in both in vitro and ex vivo models of DM. Our results demonstrate that HG induces CFs phenoconversion and FoxO1 activation. Moreover, AS1842856, a pharmacological inhibitor of FoxO1 activity, prevents CFs phenoconversion and CTGF expression increase induced by HG, whereas these results were corroborated by FoxO1 silencing. Additionally, K252a, a pharmacological blocker of CTGF receptor, prevents HG-induced CFs phenoconversion, which was corroborated with CTGF expression knockdown. Furthermore, through CFs isolation from heart of diabetic rats, we showed that hyperglycemia induces FoxO1 activation, the increase of CTGF expression and CFs phenoconversion, whereas the FoxO1 activity inhibition reverses the effects induced by hyperglycemia on CFs. Altogether, our results demonstrate that FoxO1 and CTGF are necessary for CFs phenoconversion induced by HG and suggest that both proteins are likely to become a potential targeted drug for fibrotic response induced by hyperglycemic conditions.

Modulation of the Expression of Long Non-Coding RNAs H19, GAS5, and MIAT by Endurance Exercise in the Hearts of Rats with Myocardial Infarction

Long non-coding RNAs (lncRNAs) have a critical role in the regulation of cardiovascular function. Dysregulation of lncRNAs is implicated in the progression of cardiovascular diseases including myocardial infarction (MI). Regarding the beneficial effects of exercise (Ex) on the improvement of MI, this study aimed to investigate the effects of post-MI Ex on the expression of MI-associated lncRNAs: H19, myocardial infarction association transcript (MIAT), and growth arrest specific 5 (GAS5). MI was induced by left anterior descending (LAD) coronary artery ligation in male Wistar rats. One week later, rats were exercised under a moderate-intensity protocol for 4 weeks. In the end, hemodynamic parameters and cardiac function indices were measured. Assessment of fibrotic areas and apoptosis was performed by Masson's trichrome staining and immunohistochemistry, respectively. Expression of genes was evaluated by real-time PCR. Ex significantly reduced the fibrotic areas (P < 0.05) and apoptosis and increased contractility indices (P < 0.01), and cardiac function (P < 0.05) in MI groups. The reduced expression of H19 (P < 0.01) in MI rats returned to normal levels by Ex. Ex significantly (P < 0.001) reduced the expression of MIAT and increased the expression of GAS5 (P < 0.01), which had changed in the hearts of rats with MI. The present study indicated the beneficial effect of Ex on the improvement of cardiac function and reduction of fibrosis in infarcted heart possibly through regulation of the expression of lncRNAs: H19, GAS5, and MIAT.

Prognostic potential of cardiac structural and functional parameters and N-terminal propeptide of type III procollagen in predicting cardiac fibrosis one year after myocardial infarction with preserved left ventricular ejection fraction

The aim of the study were to evaluate the prognostic potential of serum level of N-terminal propeptide procollagen type III (PIIINP) and heart parameters for predicting heart cardiac fibrosis 1 year after ST-segment elevation myocardial infarction (STEMI) with preserved left ventricular ejection fraction (LVEF). 68 patients with STEMI and preserved LVEF with acute heart failure of the I-III degree according to the Killip classification were examined. Echocardiography was performed and PIIINP levels were measured on days 1 and 12, as well as 1 year after STEMI. A year after STEMI, was performed contrast magnetic resonance imaging and patients were assigned into four groups depending on the severity of cardiac fibrosis: cardiac fibrosis 0% (n=49, 57% of 86 patients); ≤5% (n=18, 20.9%); 6-15% (n=10, 11.6%); ≥16% (n=9, 10.5%). Direct correlations between the severity of cardiac fibrosis, PIIINP level and indicators of diastolic function were established. The risk of cardiac fibrosis increases at the level of PIIINP ≥381.4 ng / ml on the 12th day after STEMI with preserved LVEF (p=0.048). Thus, measuring the level of PIIINP in the inpatient period can allow timely identification of patients with a high risk of cardiac fibrosis 1 year after STEMI with preserved LVEF.

Cardiac fibrosis: emerging agents in preclinical and clinical development

INTRODUCTION

Myocardial fibrosis is a remarkably dynamic process mediated by different molecular pathways that represent potential targets of novel therapeutic interventions. Transforming Growth Factor-beta (TGF-β), connective Tissue Growth Factor (cTGF) and Galectin-3 (Gal-3) represent the most promising targets on which research has been currently focusing.

AREA COVERED

This review initially discusses those drugs used in clinical practice for their anti-fibrotic properties and later examines emerging pathway-specific agents in preclinical and clinical development [phase I and II-concluded or ongoing trials]. We performed a PubMed, Embase and Google Scholar research including original articles, systematic reviews, ongoing and completed trials using combinations of keywords such as 'myocardial fibrosis', 'reverse remodeling', 'RAAs', 'therapy'.

EXPERT OPINION

A variety of preclinical evidences suggest that new drugs and molecules are potentially useful to target cardiac fibrosis and improve left ventricular function, reduce infarct size and scars, delay incident heart failure and cardiac dysfunction in animal models. However, there are very few clinical trials investigating the effect of such drugs in this setting, as well as a lack of new engineered molecules for specific targets.

Extracellular Matrix in Ischemic Heart Disease, Part 4/4: JACC Focus Seminar

Myocardial ischemia and infarction, both in the acute and chronic phases, are associated with cardiomyocyte loss and dramatic changes in the cardiac extracellular matrix (ECM). It has long been appreciated that these changes in the cardiac ECM result in altered mechanical properties of ischemic or infarcted myocardial segments. However, a growing body of evidence now clearly demonstrates that these alterations of the ECM not only affect the structural properties of the ischemic and post-infarct heart, but they also play a crucial and sometimes direct role in mediating a range of biological pathways, including the orchestration of inflammatory and reparative processes, as well as the pathogenesis of adverse remodeling. This final part of a 4-part JACC Focus Seminar reviews the evidence on the role of the ECM in relation to the ischemic and infarcted heart, as well as its contribution to cardiac dysfunction and adverse clinical outcomes.

Immunotherapy for Infarcts: In Vivo Postinfarction Macrophage Modulation Using Intramyocardial Microparticle Delivery of Map4k4 Small Interfering RNA

The myeloid cells infiltrating the heart early after acute myocardial infarction elaborate a secretome that largely orchestrates subsequent ventricular wall repair. Regulating this innate immune response could be a means to improve infarct healing. To pilot this concept, we utilized (β1,3-d-) glucan-encapsulated small interfering RNA (siRNA)-containing particles (GeRPs), targeting mononuclear phagocytes, delivered to mice as a one-time intramyocardial injection immediately after acute infarction. Findings demonstrated that cardiac macrophages phagocytosed GeRPs in vivo and had little systemic dissemination, thus providing a means to deliver local therapeutics. Acute infarcts were then injected in vivo with phosphate-buffered saline (PBS; vehicle) or GeRPs loaded with siRNA to Map4k4, and excised hearts were examined at 3 and 7 days by quantitative polymerase chain reaction, flow cytometry, and histology. Compared with infarcted PBS-treated hearts, hearts with intrainfarct injections of siRNA-loaded GeRPs exhibited 69–89% reductions in transcripts for Map4k4 (mitogen-activated protein kinase kinase kinase kinase 4), interleukin (IL)-1β, and tumor necrosis factor α at 3 days. Expression of other factors relevant to matrix remodeling—monocyte chemoattractant protein-1 (MCP-1), matrix metalloproteinases, hyaluronan synthases, matricellular proteins, and profibrotic factors transforming growth factor beta (TGF-β), and connective tissue growth factor (CTGF)—were also decreased. Most effects peaked at 3 days, but, in some instances (Map4k4, IL-1β, TGF-β, CTGF, versican, and periostin), suppression persisted to 7 days. Thus, direct intramyocardial GeRP injection could serve as a novel and clinically translatable platform for in vivo RNA delivery to intracardiac macrophages for local and selective immunomodulation of the infarct microenvironment.

Regulators of cardiac fibroblast cell state

Fibroblasts are the primary regulator of cardiac extracellular matrix (ECM). In response to disease stimuli cardiac fibroblasts undergo cell state transitions to a myofibroblast phenotype, which underlies the fibrotic response in the heart and other organs. Identifying regulators of fibroblast state transitions would inform which pathways could be therapeutically modulated to tactically control maladaptive extracellular matrix remodeling. Indeed, a deeper understanding of fibroblast cell state and plasticity is necessary for controlling its fate for therapeutic benefit. p38 mitogen activated protein kinase (MAPK), which is part of the noncanonical transforming growth factor β (TGFβ) pathway, is a central regulator of fibroblast to myofibroblast cell state transitions that is activated by chemical and mechanical stress signals. Fibroblast intrinsic signaling, local and global cardiac mechanics, and multicellular interactions individually and synergistically impact these state transitions and hence the ECM, which will be reviewed here in the context of cardiac fibrosis.

Cardiac fibroblast activation during myocardial infarction wound healing: Fibroblast polarization after MI

Cardiac wound healing after myocardial infarction (MI) evolves from pro-inflammatory to anti-inflammatory to reparative responses, and the cardiac fibroblast is a central player during the entire transition. The fibroblast mirrors changes seen in the left ventricle infarct by undergoing a continuum of polarization phenotypes that follow pro-inflammatory, anti-inflammatory, and pro-scar producing profiles. The development of each phenotype transition is contingent upon the MI environment into which the fibroblast enters. In this mini-review, we summarize our current knowledge regarding cardiac fibroblast activation during MI and highlight key areas where gaps remain.

Systemic blockade of ACVR2B ligands attenuates muscle wasting in ischemic heart failure without compromising cardiac function

Signaling through activin receptors regulates skeletal muscle mass and activin receptor 2B (ACVR2B) ligands are also suggested to participate in myocardial infarction (MI) pathology in the heart. In this study, we determined the effect of systemic blockade of ACVR2B ligands on cardiac function in experimental MI, and defined its efficacy to revert muscle wasting in ischemic heart failure (HF). Mice were treated with soluble ACVR2B decoy receptor (ACVR2B-Fc) to study its effect on post-MI cardiac remodeling and on later HF. Cardiac function was determined with echocardiography, and myocardium analyzed with histological and biochemical methods for hypertrophy and fibrosis. Pharmacological blockade of ACVR2B ligands did not rescue the heart from ischemic injury or alleviate post-MI remodeling and ischemic HF. Collectively, ACVR2B-Fc did not affect cardiomyocyte hypertrophy, fibrosis, angiogenesis, nor factors associated with cardiac regeneration except modification of certain genes involved in metabolism or cell growth/survival. ACVR2B-Fc, however, was able to reduce skeletal muscle wasting in chronic ischemic HF, accompanied by reduced LC3II as a marker of autophagy and increased mTOR signaling and Cited4 expression as markers of physiological hypertrophy in quadriceps muscle. Our results ascertain pharmacological blockade of ACVR2B ligands as a possible therapy for skeletal muscle wasting in ischemic HF. Pharmacological blockade of ACVR2B ligands preserved myofiber size in ischemic HF, but did not compromise cardiac function nor exacerbate cardiac remodeling after ischemic injury.

Si-Miao-Yong-An decoction attenuates cardiac fibrosis via suppressing TGF-β1 pathway and interfering with MMP-TIMPs expression

BACKGROUND

Myocardial fibrosis is an important pathological feature of pressure overload cardiac remodeling. Si-Miao-Yong-An decoction (SMYAD), a traditional Chinese formula, is now clinically used in the treatment of cardiovascular diseases in China. However, its mechanisms in the prevention of heart failure are not fully revealed.

PURPOSE

To determine whether treatment with SMYAD for 4 weeks would lead to changes in collagen metabolism and ventricular remodeling in a mice model of heart failure.

METHODS

Mice were subjected to transverse aorta constriction to generate pressure overload induced cardiac remodeling and then were administered SMYAD (14.85 g/kg/day) or captopril (16.5 mg/kg/day) intragastrically for 4 weeks after surgery. Echocardiography and immunohistochemical examination were used to evaluate the effects of SMYAD. The mRNA of collagen metabolism biomarkers were detected. Protein expression of TGF-β1/Smad and TGF-β1/TAK1/p38 pathway were assessed by Western blot.

RESULTS

SMYAD significantly improved cardiac function, increased left ventricle ejection fraction, and decreased fibrosis area and αSMA expression. Moreover, SMYAD reduced proteins expression related to collagen metabolism, including Col1, Col3, TIMP2 and CTGF. The increased levels of TGF-β1, Smad2, and Smad3 phosphorylation were attenuated in SMYAD group. In addition, SMYAD reduced the levels of TGF-β1, p-TAK1 and p-p38 compared with TAC group.

CONCLUSIONS

SMYAD improved cardiac fibrosis and heart failure by inhibition of TGF-β1/Smad and TGF-β1/TAK1/p38 pathway. SMYAD protected against cardiac fibrosis and maintained collagen metabolism balance by regulating MMP-TIMP expression. Taken together, these results indicate that SMYAD might be a promising therapeutic agent against cardiac fibrosis.

Amphiregulin promotes cardiac fibrosis post myocardial infarction by inducing the endothelial-mesenchymal transition via the EGFR pathway in endothelial cells

The endothelial-mesenchymal transition (EndMT) plays a key role in the development of cardiac fibrosis (CF) after acute myocardial infarction (AMI). The results of our previous study showed that amphiregulin (AR) expression was enhanced after MI. However, the role of AR on EndMT post MI remains unknown. This study aimed to elucidate the impact of AR on EndMT post MI and the associated molecular mechanisms. AR expression was markedly enhanced in infarct border area post MI, and endothelial cells were one of the primary cell sources of AR secretion. Stimulation with AR promoted endothelial cell proliferation, invasion, migration, collagen synthesis and EndMT. In addition, EGFR and downstream gene expression was significantly enhanced. In vivo, EndMT was significantly inhibited after lentivirus-AR-shRNA was delivered to the myocardium post MI. In addition, silencing AR ameliorated cardiac function by decreasing the extent of CF. Furthermore, the levels of EGFR pathway components in endothelial cells extracted from infarct border myocardium were all significantly decreased in lentivirus-AR-shRNA-treated MI mice. Our results demonstrate that AR induces CF post MI by enhancing EndMT in endothelial cells. Thus, targeting the regulation of AR may provide a potentially novel therapeutic option for CF after MI.

Infarct Zone: a Novel Platform for Exosome Trade in Cardiac Tissue Regeneration

The global incidence of coronary artery diseases (CADs), especially myocardial infarction (MI), has drastically increased in recent years. Even though the conventional therapies have improved the outcomes, the post-MI complications and the increased rate of recurrence among the survivors are still alarming. Molecular events associated with the pathogenesis and the adaptive responses of the surviving myocardium are largely unknown. Focus on exosome-mediated signaling for cell-cell/matrix communications at the infarct zone reflects an emerging opportunity in cardiac regeneration. Also, cardiac tissue engineering provides promising insights for the next generation of therapeutic approaches in the management of CADs. In this article, we critically reviewed the current understanding on the biology of cardiac exosomes, therapeutic potential of exosomes, and recent developments in cardiac tissue engineering and discussed novel translational approaches based on tissue engineering and exosomes for cardiac regeneration and CADs.

Useful applications of growth factors for cardiovascular regenerative medicine

Novel advances for cardiovascular diseases (CVDs) include regenerative approaches for fibrosis, hypertrophy, and neoangiogenesis. Studies indicate that growth factor (GF) signaling could promote heart repair since most of the evidence is derived from preclinical models. Observational studies have evaluated GF serum/plasma levels as feasible biomarkers for risk stratification of CVDs. Noteworthy, two clinical interventional published studies showed that the administration of growth factors (GFs) induced beneficial effect on left ventricular ejection fraction (LVEF), myocardial perfusion, end-systolic volume index (ESVI). To date, large scale ongoing studies are in Phase I-II and mostly focussed on intramyocardial (IM), intracoronary (IC) or intravenous (IV) administration of vascular endothelial growth factor (VEGF) and fibroblast growth factor-23 (FGF-23) which result in the most investigated GFs in the last 10 years. Future data of ongoing randomized controlled studies will be crucial in understanding whether GF-based protocols could be in a concrete way effective in the clinical setting.

Radiotherapy-induced heart disease: a review of the literature

Radiotherapy as one of the four pillars of cancer therapy plays a critical role in the multimodal treatment of thoracic cancers. Due to significant improvements in overall cancer survival, radiotherapy-induced heart disease (RIHD) has become an increasingly recognized adverse reaction which contributes to major radiation-associated toxicities including non-malignant death. This is especially relevant for patients suffering from diseases with excellent prognosis such as breast cancer or Hodgkin’s lymphoma, since RIHD may occur decades after radiotherapy. Preclinical studies have enriched our knowledge of many potential mechanisms by which thoracic radiotherapy induces heart injury. Epidemiological findings in humans reveal that irradiation might increase the risk of cardiac disease at even lower doses than previously assumed. Recent preclinical studies have identified non-invasive methods for evaluation of RIHD. Furthermore, potential options preventing or at least attenuating RIHD have been developed. Ongoing research may enrich our limited knowledge about biological mechanisms of RIHD, identify non-invasive early detection biomarkers and investigate potential treatment options that might attenuate or prevent these unwanted side effects. Here, we present a comprehensive review about the published literature regarding clinical manifestation and pathological alterations in RIHD. Biological mechanisms and treatment options are outlined, and challenges in RIHD treatment are summarized.

Nerolidol attenuates cyclophosphamide-induced cardiac inflammation, apoptosis and fibrosis in Swiss Albino mice

Incidence and prevalence of cancer is an alarming situation globally. For the treatment of cancer many anticancer drugs have been developed but, unfortunately, their potential cardiotoxic side effects raised serious concerns about their use among clinicians. Cyclophosphamide is a potent anticancer and immunosuppressant drug but its use is limited due to cardiotoxic side effect. Thus, there is a need for the development of certain drug which can reduce cardiotoxicity and can be used as an adjuvant therapy in cancer patients. In this direction we, therefore planned to evaluate nerolidol (NER) for its cardioprotective potential against cyclophosphamide-induced cardiotoxicity in Swiss Albino mice. Animals were divided into 6 groups. Vehicle control; Cyclophosphamide (CP 200); NER 400 per se; NER 200 + CP 200; NER 400 + CP 200; and fenofibrate (FF 80) + CP 200. Dosing was done for 14 days along with a single dose of CP 200 on the 7th day. On 15th day animals were sacrificed and various biochemical parameters pertaining to oxidative stress, nitrative stress, inflammation, apoptosis and fibrosis were estimated in the blood and heart tissues. Histopathological analysis (H & E and Masson's trichrome staining); ultrastructural analysis (transmission electron microscopy) and immunohistochemical analysis were also performed along with mRNA expression and molecular docking to establish the cardioprotective potential of nerolidol. Nerolidol acted as a potent cardioprotective molecule and attenuated CP-induced cardiotoxicity.

Mechanisms of cardiac collagen deposition in experimental models and human disease

The inappropriate deposition of extracellular matrix within the heart (termed cardiac fibrosis) is associated with nearly all types of heart disease, including ischemic, hypertensive, diabetic, and valvular. This alteration in the composition of the myocardium can physically limit cardiomyocyte contractility and relaxation, impede electrical conductivity, and hamper regional nutrient diffusion. Fibrosis can be grossly divided into 2 types, namely reparative (where collagen deposition replaces damaged myocardium) and reactive (where typically diffuse collagen deposition occurs without myocardial damage). Despite the widespread association of fibrosis with heart disease and general understanding of its negative impact on heart physiology, it is still not clear when collagen deposition becomes pathologic and translates into disease symptoms. In this review, we have summarized the current knowledge of cardiac fibrosis in human patients and experimental animal models, discussing the mechanisms that have been deduced from the latter in relation to the former. Because assessment of the extent of fibrosis is paramount both as a research tool to further understanding and as a clinical tool to assess patients, we have also summarized the current state of noninvasive/minimally invasive detection systems for cardiac fibrosis. Albeit not exhaustive, our aim is to provide an overview of the current understanding of cardiac fibrosis, both clinically and experimentally.