transforming-growth-factor-beta and Myocarditis

Chagas disease is caused by the trypanosomatid Trypanosoma cruzi, which chronically causes heart problems in up to 30% of infected patients. Chagas disease was initially restricted to Latin America. However, due to migratory events, this disease may become a serious worldwide health problem. During Chagas disease, many patients die of cardiac arrhythmia despite the apparent benefits of anti-arrhythmic therapy (e.g., amiodarone). Here, we assimilate the cardiac form of Chagas disease to an inflammatory cardiac disease. Evidence from the literature, mostly provided using experimental models, supports this view and argues in favor of new strategies for treating cardiac arrhythmias in Chagas disease by modulating cytokine production and/or action. But the complex nature of myocardial inflammation underlies the need to better understand the molecular mechanisms of the inflammatory response during Chagas disease. Here, particular attention has been paid to tumor necrosis factor alpha (TNF) and transforming growth factor beta (TGF-β) although other cytokines may be involved in the chagasic cardiomyopathy.

Topics: Action Potentials; Animals; Anti-Inflammatory Agents; Atrial Remodeling; Chagas Cardiomyopathy; Heart Conduction System; Heart Rate; Host-Pathogen Interactions; Humans; Inflammation Mediators; Myocardial Contraction; Myocarditis; Myocytes, Cardiac; Signal Transduction; Transforming Growth Factor beta; Trypanosoma cruzi; Tumor Necrosis Factor-alpha; Ventricular Remodeling

The action of transforming-growth-factor (TGF)-beta following inflammatory responses is characterized by increased production of extracellular matrix (ECM) components, as well as mesenchymal cell proliferation, migration, and accumulation. Thus, TGF-beta is important for the induction of fibrosis often associated with chronic phases of inflammatory diseases. This common feature of TGF-related pathologies is observed in many different organs. Therefore, in addition to the description of the common TGF-beta-pathway, this review focuses on TGF-beta-related pathogenetic effects in different pathologies/organs, i. e., arthritis, diabetic nephropathy, colitis/Crohn's disease, radiation-induced fibrosis, and myocarditis (including their similarities and dissimilarities). However, TGF-beta exhibits both exacerbating and ameliorating features, depending on the phase of disease and the site of action. Due to its central role in severe fibrotic diseases, TGF-beta nevertheless remains an attractive therapeutic target, if targeted locally and during the fibrotic phase of disease.

Topics: Animals; Arthritis, Rheumatoid; Diabetic Nephropathies; Fibrosis; Humans; Inflammation; Intestines; Myocarditis; Radiation, Ionizing; Signal Transduction; Transforming Growth Factor beta

Topics: Animals; Cardiomegaly; Cell Cycle; Cytokines; Gene Expression Regulation; Heart; Heart Transplantation; Humans; Ligands; Myocarditis; Myocardium; Receptors, Transforming Growth Factor beta; Signal Transduction; Transcription, Genetic; Transforming Growth Factor beta

To better understand the formation of the cardiovascular system and its disease states, models amenable to manipulation must be developed. In this article we present two models. One is a small animal model for an inflammatory disorder that can lead to heart failure. Production of this model is based on the ability of blastocyst-derived embryonic stem cells, which can be genetically altered in vitro by a technique called gene targeting, to reconstitute an entire animal when reintroduced into a blastocyst and allowed to colonize the germ line of the resulting chimeric embryo. The other model is based on the capacity of embryonic stem cells to differentiate in culture into embryo-like structures called embryoid bodies. Embryoid bodies contain angioblasts, or prevascular endothelial cells, which can be induced to undergo aspects of vascular development by manipulation of culture conditions.

Topics: Animals; Blood Vessels; Cell Differentiation; Disease Models, Animal; Embryo, Mammalian; Embryo, Nonmammalian; Embryonic and Fetal Development; Genetic Engineering; Heart Diseases; Myocarditis; Stem Cells; Transforming Growth Factor beta

It is controversial whether myocardial fibrosis in end-stage dilated cardiomyopathy (DCM) is associated with altered collagen type I/type III (Col I/Col III) ratio.. Patients with DCM (ejection fraction [EF] <50%, n=12) and with mild global left ventricular dysfunction (EF >50%, n=18) were examined. Col I, Col III, and transforming growth factors-beta1 (TGF-beta1) and -beta2 (TGF-beta2) gene expression in endomyocardial biopsies was evaluated by quantitative competitive reverse transcriptase-polymerase chain reaction (qRT-PCR). Collagen content was quantified after picrosirius red and immunohistological staining and by hydroxyproline assay. In patients with EF <50%, there was a pronounced 2- to 6-fold increase of myocardial Col I mRNA abundance (P<0.01), with a corresponding 1.6-fold increase at the protein level versus that found in patients with EF >50%. The Col III mRNA abundance showed a 2.0-fold increase (P<0.04). There was a relevant shift in the Col I/Col III mRNA ratio for DCM patients (Col I/Col III, 8.2) compared with patients with an EF >50% (Col I/Col III, 6. 4). In addition, total collagen content was increased in patients with EF <50% (n=3) (4.3+/-0.1%) compared with patients with EF >50% (n=8) (2.7+/-0.9%) (P<0.004). The biochemically determined ratio of hydroxyproline/total protein (n=12) was correlated to the Col I mRNA abundance (P<0.05, r=0.77). TGF-beta1 and TGF-beta2 showed elevated myocardial mRNA abundances (1- to 7-fold and 4- to 5-fold, respectively) in DCM patients.. Differential increase of Col I and Col III leads to an increased Col I/Col III ratio in DCM myocardium. Because Col I provides substantial tensile strength and stiffness, this may contribute to systolic and in particular diastolic dysfunction in DCM.

Topics: Biopsy; Cardiomyopathy, Dilated; Collagen; Female; Gene Expression Regulation; Hemodynamics; Humans; Hydroxyproline; Male; Middle Aged; Myocarditis; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Transforming Growth Factor beta

The present study aimed to explore the pathogenesis of autoimmune myocarditis induced by PD-1 inhibitors and their potential therapeutic targets. Mouse models of autoimmune myocarditis induced by PD-1 inhibitor in mouse models of polymyositis were established. The expression level of PD-1 and regulatory T cells (Tregs), CD4, CD8 + T cells, inflammation, apoptosis and autophagy-related factors, including IL-6, TGF-β, AMA-M2, Fas/FasL, LC3 and p62 were detected in peripheral blood, muscle or myocardium of mice in each group, using ELISA, RT-PCR, Western Blot and immunofluorescence. In addition, HE and TUNEL staining and ultrastructural scanning were performed on the myocardium of mice in each group. Results showed that the expression level of PD-1 in the two myositis groups was significantly lower than that in the control group, and the level of PD-1 was lower in the myocarditis group than that in the polymyositis group. In the myocardium, TGF-β, p62, and Tregs proportion showed the same expression level trend as PD-1, while CD8, IL-6, IL-10 and LC3 showed the opposite trend. Levels of Fas/FasL were significantly higher in both myositis groups, but were slightly lower in the myocarditis group, as was AMA-M2. Inflammation, apoptosis, and autophagy were observed in both myositis groups, but were more severe in the myocarditis group. In summary, the decreased expression level of PD-1 leads to decreased Tregs level in the myocardium, aggravated inflammatory response, apoptosis and autophagy, which may be the pathological mechanism of myocarditis induced by PD-1 inhibitors.

Topics: Animals; Apoptosis; Autophagy; Immune Checkpoint Inhibitors; Inflammation; Interleukin-6; Mice; Myocarditis; Myocardium; Myositis; Polymyositis; Programmed Cell Death 1 Receptor; T-Lymphocytes, Regulatory; Transforming Growth Factor beta

Latency associated peptide (LAP) is a protein expressed on the membrane of some regulatory T cells (Treg). LAP

Topics: Animals; Coxsackievirus Infections; Disease Models, Animal; Lymphocyte Count; Male; Mice, Inbred BALB C; Myocarditis; Peptides; Protein Precursors; T-Lymphocyte Subsets; T-Lymphocytes, Regulatory; Transforming Growth Factor beta

Coxsackievirus B3 (CVB3) is the primary cause of viral myocarditis. An early and abundant neutrophil accumulation in the myocardium is a hallmark of early CVB3 infection. Yet the relative contribution of neutrophils to host susceptibility to CVB3 myocarditis remains largely unknown. Herein, peripheral neutrophil depletion was implemented in a BALB/c mouse model of acute CVB3 myocarditis using the specific 1A-8 (anti-Ly6G) or a RB6-8C5 (anti-Gr-1) mAb covering a wide range. Anti-Ly6G treatment led to systemic neutropenia throughout the disease, but did not alter virus replication, disease susceptibility and histopathological changes in the heart and pancreas of mice. In contrast, depletion of both neutrophils and monocytes/macrophages by anti-Gr-1 mAb prior to and after infection significantly promoted susceptibility of mice to CVB3 infection which was associated with exacerbated cardiac and pancreatic viral load. However, depletion of Gr1+ cells significantly suppressed acute myocarditis and pancreatic acini destruction at day 7 post infection via reducing Ly6C

Topics: Animals; Antigens, Ly; Coxsackievirus Infections; Cytokines; Disease Models, Animal; Fibrosis; Heart; Inflammation; Leukocytes; Male; Mice; Mice, Inbred BALB C; Myocarditis; Neutropenia; Neutrophils; Pancreas; Receptors, Chemokine; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha; Viral Load; Virus Replication

Myocardial fibrosis critically contributes to cardiac dysfunction in inflammatory dilated cardiomyopathy (iDCM). Activation of transforming growth factor-β (TGF-β) signalling is a key-step in promoting tissue remodelling and fibrosis in iDCM. Downstream mechanisms controlling these processes, remain elusive.. Experimental autoimmune myocarditis (EAM) was induced in BALB/c mice with heart-specific antigen and adjuvant. Using heart-inflammatory precursors, as well as mouse and human cardiac fibroblasts, we demonstrated rapid secretion of Wnt proteins and activation of Wnt/β-catenin pathway in response to TGF-β signalling. Inactivation of extracellular Wnt with secreted Frizzled-related protein 2 (sFRP2) or inhibition of Wnt secretion with Wnt-C59 prevented TGF-β-mediated transformation of inflammatory precursors and cardiac fibroblasts into pathogenic myofibroblasts. Inhibition of T-cell factor (TCF)/β-catenin-mediated transcription with ICG-001 or genetic loss of β-catenin also prevented TGF-β-induced myofibroblasts formation. Furthermore, blocking of Smad-independent TGF-β-activated kinase 1 (TAK1) pathway completely abrogated TGF-β-induced Wnt secretion. Activation of Wnt pathway in the absence of TGF-β, however, failed to transform precursors into myofibroblasts. The critical role of Wnt axis for cardiac fibrosis in iDCM is also supported by elevated Wnt-1/Wnt-5a levels in human samples from hearts with myocarditis. Accordingly, and as an in vivo proof of principle, inhibition of Wnt secretion or TCF/β-catenin-mediated transcription abrogated the development of post-inflammatory fibrosis in EAM.. We identified TAK1-mediated rapid Wnt protein secretion as a novel downstream key mechanism of TGF-β-mediated myofibroblast differentiation and myocardial fibrosis progression in human and mouse myocarditis. Thus, pharmacological targeting of Wnts might represent a promising therapeutic approach against iDCM in the future.

Topics: Animals; Autoimmune Diseases; Benzeneacetamides; beta Catenin; Cell Differentiation; Disease Progression; Fibrosis; Humans; MAP Kinase Kinase Kinases; Membrane Proteins; Mice, Inbred BALB C; Myocarditis; Myocardium; Myofibroblasts; Pyridines; Signal Transduction; Stem Cells; TCF Transcription Factors; Transforming Growth Factor beta; Ventricular Dysfunction; Wnt Proteins; Wnt-5a Protein; Wnt1 Protein

Platelets are essential for primary hemostasis; however, platelet activation also plays an important proinflammatory role. Inflammation promotes the development of cardiac fibrosis and heart failure induced by hypertension. In this study, we aimed to determine whether inhibiting platelet activation using clopidogrel could inhibit hypertension-induced cardiac inflammation and fibrosis.. Using a mouse model of angiotensin II (Ang II) infusion (1,500 ng/[kg·min] for 7 days), we determined the role of platelet activation in Ang II infusion-induced cardiac inflammation and fibrosis using a P2Y12 receptor inhibitor, clopidogrel (50 mg/[kg·day]).. CD41 staining showed that platelets accumulated in Ang II-infused hearts. Clopidogrel treatment inhibited Ang II infusion-induced accumulation of α-SMA(+) myofibroblasts and cardiac fibrosis (4.17 ± 1.26 vs. 1.46 ± 0.81, p < 0.05). Infiltration of inflammatory cells, including Mac-2(+) macrophages and CD45(+)Ly6G(+) neutrophils (30.38 ± 4.12 vs. 18.7 ± 2.38, p < 0.05), into Ang II-infused hearts was also suppressed by platelet inhibition. Real-time PCR and immunohistochemical staining showed that platelet inhibition significantly decreased the expression of interleukin-1β and transforming growth factor-β. Acute injection of Ang II or PE stimulated platelet activation and platelet-leukocyte conjugation, which were abolished by clopidogrel treatment.. Thus, inhibition of platelet activation by clopidogrel prevents cardiac inflammation and fibrosis in response to Ang II. Taken together, our results indicate Ang II infusion-induced hypertension stimulated platelet activation and platelet-leukocyte conjugation, which initiated inflammatory responses that contributed to cardiac fibrosis.

Topics: Angiotensin II; Animals; Clopidogrel; Fibrosis; Hypertension; Interleukin-1beta; Male; Mice; Mice, Inbred C57BL; Myocarditis; Myocardium; Platelet Activation; Platelet Aggregation Inhibitors; Purinergic P2Y Receptor Antagonists; Ticlopidine; Transforming Growth Factor beta

Experimental autoimmune myocarditis (EAM) model mirrors important mechanisms of inflammatory dilated cardiomyopathy (iDCM). In EAM, inflammatory CD133(+) progenitors are a major cellular source of cardiac myofibroblasts in the post-inflammatory myocardium. We hypothesized that exogenous delivery of macrophage-colony-stimulating factor (M-CSF) can stimulate macrophage lineage differentiation of inflammatory progenitors and, therefore, prevent their naturally occurring myofibroblast fate in EAM.. EAM was induced in wild-type (BALB/c) and nitric oxide synthase 2-deficient (Nos2(-/-)) mice and CD133(+) progenitors were isolated from inflamed hearts. In vitro, M-CSF converted inflammatory CD133(+) progenitors into nitric oxide-producing F4/80(+) macrophages and prevented transforming growth factor-β-mediated myofibroblast differentiation. Importantly, only a subset of heart-infiltrating CD133(+) progenitors expresses macrophage-specific antigen F4/80 in EAM. These CD133(+)/F4/80(hi) cells show impaired myofibrogenic potential compared with CD133(+)/F4/80(-) cells. M-CSF treatment of wild-type mice with EAM at the peak of disease markedly increased CD133(+)/F4/80(hi) cells in the myocardium, and CD133(+) progenitors isolated from M-CSF-treated mice failed to differentiate into myofibroblasts. In contrast, M-CSF was not effective in converting CD133(+) progenitors from inflamed hearts of Nos2(-/-) mice into macrophages, and M-CSF treatment did not result in increased CD133(+)/F4/80(hi) cell population in hearts of Nos2(-/-) mice. Accordingly, M-CSF prevented post-inflammatory fibrosis and left ventricular dysfunction in wild-type but not in Nos2(-/-) mice.. Active and NOS2-dependent induction of macrophage lineage differentiation abrogates the myofibrogenic potential of heart-infiltrating CD133(+) progenitors. Modulating the in vivo differentiation fate of specific progenitors might become a novel approach for the treatment of inflammatory heart diseases.

Topics: AC133 Antigen; Amino Acid Sequence; Animals; Antigens, CD; Antigens, Differentiation; Autoimmune Diseases; Cell Differentiation; Cells, Cultured; Fibrosis; Glycoproteins; Macrophage Colony-Stimulating Factor; Macrophages; Mice; Mice, Inbred BALB C; Molecular Sequence Data; Myocarditis; Myocardium; Nitric Oxide Synthase Type II; Peptides; Stem Cells; Transforming Growth Factor beta; Ventricular Dysfunction, Left

The Th17/interleukin (IL)-17 axis controls inflammation and might be important in the pathogenesis of experimental autoimmune myocarditis (EAM) and other autoimmune diseases. However, the mechanism underlying the increased Th17 cell response in coxsackievirus-induced myocarditis remains unclear. This study aimed to elucidate the regulatory mechanisms affected by blocking IL-17A responses in acute virus-induced myocarditis (AVMC) mice. The results showed that IL-17A and COX-2 proteins were significantly increased in the cardiac tissue of acute myocarditis, as were Th17 cells in the spleen. Using anti-mouse IL-17Ab to block IL-17A on day 7 of the viral myocarditis led to decreased expressions of cardiac tumor-necrosis factor alpha, IL-17A and transforming growth factor beta in AVMC mice compared to isotype control mice. COX-2 and prostaglandin E2 proteins were dramatically elevated, followed by marked reductions in CVB3 replication and myocardial injury. These results hint that the Th17/IL-17 axis is intimately associated with viral replication in acute myocarditis via induction of COX-2 and prostaglandin E2.

Topics: Animals; Coxsackievirus Infections; Cyclooxygenase 2; Dinoprostone; Enterovirus B, Human; HeLa Cells; Humans; Interleukin-17; Mice; Mice, Inbred BALB C; Myocarditis; Myocardium; Spleen; Th17 Cells; Transforming Growth Factor beta; Tumor Cells, Cultured; Tumor Necrosis Factor-alpha; Virus Replication

Cardiac fibrosis after myocardial infarction (MI) has been identified as a key factor in the development of heart failure. Although dysregulation of microRNA (miRNA) is involved in various pathophysiological processes in the heart, the role of miRNA in fibrosis regulation after MI is not clear. Previously we observed the correlation between fibrosis and the miR-24 expression in hypertrophic hearts, herein we assessed how miR-24 regulates fibrosis after MI. Using qRT-PCR, we showed that miR-24 was down-regulated in the MI heart; the change in miR-24 expression was closely related to extracellular matrix (ECM) remodelling. In vivo, miR-24 could improve heart function and attenuate fibrosis in the infarct border zone of the heart two weeks after MI through intramyocardial injection of Lentiviruses. Moreover, in vitro experiments suggested that up-regulation of miR-24 by synthetic miR-24 precursors could reduce fibrosis and also decrease the differentiation and migration of cardiac fibroblasts (CFs). TGF-β (a pathological mediator of fibrotic disease) increased miR-24 expression, overexpression of miR-24 reduced TGF-β secretion and Smad2/3 phosphorylation in CFs. By performing microarray analyses and bioinformatics analyses, we found furin to be a potential target for miR-24 in fibrosis (furin is a protease which controls latent TGF-β activation processing). Finally, we demonstrated that protein and mRNA levels of furin were regulated by miR-24 in CFs. These findings suggest that miR-24 has a critical role in CF function and cardiac fibrosis after MI through a furin-TGF-β pathway. Thus, miR-24 may be used as a target for treatment of MI and other fibrotic heart diseases.

Topics: Animals; Disease Models, Animal; Down-Regulation; Extracellular Matrix; Fibroblasts; Fibrosis; Furin; Heart Failure; Mice; MicroRNAs; Myocardial Infarction; Myocarditis; Smad2 Protein; Smad3 Protein; Transforming Growth Factor beta; Up-Regulation

To observe the time course of interleukin (IL)-21 and related cytokines expression in rats with experimental autoimmune myocarditis (EAM).. Antigen was prepared with an emulsion of porcine cardiac myosin in complete Freund's adjuvant, plus Mycobacterium tuberculosis H37Ra strain. EAM model was made by hypodermic injection of myosin in hind legs of Lewis rats.mRNA expression of IL-21 and related cytokines (IL-21R, IL-17, TGF-β, IL-6) in different tissues (heart, liver, spleen, kidney) were determined at 2 weeks after immunization by RT-PCR and quantitative real-time RT-PCR. Furthermore, the time course of IL-21 and related cytokines expression in the acute phase of EAM (2 w, 3 w, 4 w) was determined by quantitative real-time RT-PCR, and IL-21, IL-17 protein expression was determined by Western blot and ELISA. The location of IL-21R was examined by immunohistochemistry at 2 w after immunization.. Histopathology examination evidenced abundant mononuclear cells in the myocardium of 2 weeks EAM rats. Fibrosis and multinucleated giant cells were observed in the myocardium of 3 weeks EAM rats. Inflammation was reduced and large amount of fibrosis could be found in 4 weeks EAM rats. The heart weight/body weight ratio in normal, EAM 2 w, 3 w, 4 w group was (3.011 ± 0.117) mg/g, (4.736 ± 1.279) mg/g, (7.200 ± 0.308) mg/g and (4.622 ± 0.978) mg/g respectively. IL-21 mainly expressed in heart and spleen, IL-21R, IL-17, TGF-β mainly expressed in spleen, and IL-17, IL-6 mainly expressed in heart of EAM rats. IL-21R mainly distributed in cardiomyocytes of 2 weeks EAM rats. In line with pathological EAM course, the expression of IL-21 and related cytokines peaked at 2 weeks and then returned to normal at 4 weeks after immunization.. IL-21 and related cytokines were involved in the pathological process of EAM, upregulated IL-21 expression might promote Th17 cell differentiation and enhance Th17 cell secretion.

Topics: Animals; Autoimmune Diseases; Disease Models, Animal; Interleukin-17; Interleukin-6; Interleukins; Male; Myocarditis; Myocardium; Rats; Rats, Inbred Lew; Th17 Cells; Transforming Growth Factor beta

Transgenic mice with cardiac-restricted overexpression of tumor necrosis factor (MHCsTNF mice) develop progressive myocardial fibrosis, diastolic dysfunction, and adverse cardiac remodeling. Insofar as tumor necrosis factor (TNF) does not directly stimulate fibroblast collagen synthesis, we asked whether TNF-induced fibrosis was mediated indirectly through interactions between mast cells and cardiac fibroblasts.. Cardiac mast cell number increased 2 to 3 fold (P<0.001) in MHCsTNF mice compared with littermate controls. Outcrossing MHCsTNF mice with mast cell-deficient (c-kit(-/-)) mice showed that the 11-fold increase (P<0.001) in collagen volume fraction in MHCsTNF/c-kit(+/-) mice was abrogated in MHCsTNF/c-kit(-/-) mice, and that the leftward shifted left ventricular pressure-volume curve in the MHCsTNF/c-kit(+/-) mice was normalized in the MHCsTNF/c-kit(-/-) hearts. Furthermore, the increase in transforming growth factor β1 and type I transforming growth factor β receptor messenger RNA levels was significantly (P=0.03, P=0.01, respectively) attenuated in MHCsTNF/c-kit(-/-) when compared with MHCsTNF/c-kit(+/-) mice. Coculture of fibroblasts with mast cells resulted in enhanced α-smooth muscle actin expression, increased proliferation and collagen messenger RNA expression, and increased contraction of 3-dimensional collagen gels in MHCsTNF fibroblasts compared with littermate fibroblasts. The effects of mast cells were abrogated by type I transforming growth factor β receptor antagonist NP-40208.. These results suggest that increased mast cell density with resultant mast cell-cardiac fibroblast cross-talk is required for the development of myocardial fibrosis in inflammatory cardiomyopathy. Cardiac fibroblasts exposed to sustained inflammatory signaling exhibit an increased repertoire of profibrotic phenotypic responses in response to mast cell mediators.

Topics: Animals; Cell Communication; Endomyocardial Fibrosis; Fibroblasts; Gene Expression; Mast Cells; Mice; Mice, Transgenic; Myocarditis; Myocardium; Phenotype; Primary Cell Culture; Pteridines; Receptors, Transforming Growth Factor beta; Signal Transduction; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

Coxsackievirus B3 infection is an excellent model of human myocarditis and dilated cardiomyopathy. Cardiac injury is caused either by a direct cytopathic effect of the virus or through immune-mediated mechanisms. Regulatory T cells (Tregs) play an important role in the negative modulation of host immune responses and set the threshold of autoimmune activation. This study was designed to test the protective effects of Tregs and to determine the underlying mechanisms.. Carboxyfluorescein diacetate succinimidyl ester-labeled Tregs or naïve CD4(+) T cells were injected intravenously once every 2 weeks 3 times into mice. The mice were then challenged with intraperitoneal coxsackievirus B3 immediately after the last cell transfer. Transfer of Tregs showed higher survival rates than transfer of CD4(+) T cells (P=0.0136) but not compared with the PBS injection group (P=0.0589). Interestingly, Tregs also significantly decreased virus titers and inflammatory scores in the heart. Transforming growth factor-beta and phosphorylated AKT were upregulated in Tregs-transferred mice and coxsackie-adenovirus receptor expression was decreased in the heart compared with control groups. Transforming growth factor-beta decreased coxsackie-adenovirus receptor expression and inhibited coxsackievirus B3 infection in HL-1 cells and neonatal cardiac myocytes. Splenocytes collected from Treg-, CD4(+) T-cell-, and PBS-treated mice proliferated equally when stimulated with heat-inactivated virus, whereas in the Treg group, the proliferation rate was reduced significantly when stimulated with noninfected heart tissue homogenate.. Adoptive transfer of Tregs protected mice from coxsackievirus B3-induced myocarditis through the transforming growth factor beta-coxsackie-adenovirus receptor pathway and thus suppresses the immune response to cardiac tissue, maintaining the antiviral immune response.

Topics: Adaptive Immunity; Animals; Cells, Cultured; Constitutive Androstane Receptor; Disease Models, Animal; Enterovirus B, Human; Kaplan-Meier Estimate; Mice; Mice, Inbred C57BL; Myocarditis; Myocytes, Cardiac; Phosphorylation; Proto-Oncogene Proteins c-akt; Rats; Rats, Sprague-Dawley; Receptors, Cytoplasmic and Nuclear; T-Lymphocytes, Regulatory; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

Myocardial fibrosis is a hallmark of inflammation-triggered end-stage heart disease, a common cause of heart failure in young patients.. We used CD4(+) T-cell-mediated experimental autoimmune myocarditis model to determine the parameters regulating cardiac fibrosis in inflammatory heart disease.. alpha-Myosin heavy chain peptide/complete Freund's adjuvant immunization was used to induce experimental autoimmune myocarditis in BALB/c mice. Chimeric mice, reconstituted with enhanced green fluorescence protein (EGFP)(+) bone marrow, were used to track the fate of inflammatory cells. Prominin-1(+) cells were isolated from the inflamed hearts, cultured in vitro and injected intracardially at different stages of experimental autoimmune myocarditis. Transforming growth factor (TGF)-beta-mediated fibrosis was addressed using anti-TGF-beta antibody treatment. Myocarditis peaked 21 days after immunization and numbers of cardiac fibroblasts progressively increased on follow-up. In chimeric mice, >60% of cardiac fibroblasts were EGFP(+) 46 days after immunization. At day 21, cardiac infiltrates contained approximately 30% of prominin-1(+) progenitors. In vitro and in vivo experiments confirmed that prominin-1(+) but not prominin-1(-) cells isolated from acutely inflamed hearts represented the cellular source of cardiac fibroblasts at late stages of disease, characterized by increased TGF-beta levels within the myocardium. Mechanistically, the in vitro differentiation of heart-infiltrating prominin-1(+) cells into fibroblasts depended on TGF-beta-mediated phosphorylation of Smad proteins. Accordingly, anti-TGF-beta antibody treatment prevented myocardial fibrosis in immunized mice.. Taken together, heart-infiltrating prominin-1(+) progenitors are the major source of subsequent TGF-beta-triggered cardiac fibrosis in experimental autoimmune myocarditis. Recognizing the critical, cytokine-dependent role of bone marrow-derived progenitors in cardiac remodeling might result in novel treatment concepts against inflammatory heart failure.

Topics: AC133 Antigen; Animals; Antibodies; Antigens, CD; Autoimmune Diseases; CD4-Positive T-Lymphocytes; Cell Lineage; Cell Transdifferentiation; Cells, Cultured; Collagen; Disease Models, Animal; Fibroblasts; Fibrosis; Freund's Adjuvant; Glycoproteins; Green Fluorescent Proteins; Leukocyte Common Antigens; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Transgenic; Myocarditis; Myocardium; Myosin Heavy Chains; Peptides; Phosphorylation; Signal Transduction; Smad Proteins; Stem Cell Transplantation; Stem Cells; Time Factors; Transforming Growth Factor beta

Topics: AC133 Antigen; Animals; Antigens, CD; Autoimmune Diseases; CD4-Positive T-Lymphocytes; Cell Lineage; Cell Transdifferentiation; Collagen; Disease Models, Animal; Fibroblasts; Fibrosis; Glycoproteins; Humans; Leukocyte Common Antigens; Mice; Myocarditis; Myocardium; Peptides; Signal Transduction; Stem Cells; Time Factors; Transforming Growth Factor beta

Th17 cells have been recognized as the central effectors in organ-related autoimmune diseases. IL-6 is a key factor that reciprocally regulates Th17 and Foxp3(+) Treg differentiation by inhibition of TGF-beta induced Foxp3 and induction of RORgammat, a Th17 lineage-specific transcription factor. Recently IL-21 has been suggested to induce RORgammat and Th17 development in the absence of IL-6. However, the relevance of IL-21 for Th17-dependent inflammatory responses in vivo remains unclear. In this study, we demonstrate that differentiation of IL-17-producing CD4 T cells, their recruitment to inflamed organs, and the development of autoimmune disease was not affected in il21R(-/-) and il21(-/-) mice in models of myelin oligodendrocyte glycoprotein-induced autoimmune encephalitis and autoimmune myocarditis. IL-6 induced Th17 differentiation independent of and much more potently than IL-21 in vitro. These data suggest that IL-6 is sufficient to drive Th17 development and associated autoimmunity in vivo in the absence of IL-21 or IL-21R.

Topics: Animals; Autoimmune Diseases; Autoimmunity; Disease Models, Animal; Encephalomyelitis, Autoimmune, Experimental; Interleukin-17; Interleukin-6; Interleukins; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Knockout; Myocarditis; Nervous System Autoimmune Disease, Experimental; Nuclear Receptor Subfamily 1, Group F, Member 3; Receptors, Interleukin-21; Receptors, Retinoic Acid; Receptors, Thyroid Hormone; T-Lymphocytes, Helper-Inducer; T-Lymphocytes, Regulatory; Transforming Growth Factor beta

Transforming growth factor (TGF)-beta is a locally generated cytokine involved in healing processes and tissue fibrosis, all relevant for cardiac remodeling and the development of heart failure after myocardial infarction (MI). However, data regarding the function of TGF-beta after ischemic injury are inconclusive.. We tested the effect of TGF-beta inhibition by application of a blocking antibody in mice with MI. Starting 1 week before or 5 days after coronary artery ligation mice were treated with intraperitoneal injections of an anti-TGF-beta (5 mg/kg bodyweight 1D11, Genzyme) or control antibody. Mortality over 8 weeks was significantly higher in the groups treated with the anti-TGF-beta antibody. Both, pre or post MI treatments were associated with increased left ventricular dilatation after MI as determined by serial echocardiography. In anti-TGF-beta treated mice collagen production decreased and matrix-metalloproteinase expression increased. However, the expression of TGF pro-inflammatory cytokine TNF-alpha was not altered by the treatment. Anti-TGF-beta treatment before or after coronary artery ligation increases mortality and worsens left ventricular remodeling in mice with non-reperfused MI. The detrimental effects of TGF-beta inhibition may be mediated by alterations in extracellular matrix remodeling.

Topics: Animals; Collagen; Echocardiography; Electrocardiography; Mice; Mice, Inbred C57BL; Myocardial Infarction; Myocarditis; Survival Analysis; Transforming Growth Factor beta; Ventricular Dysfunction, Left; Ventricular Remodeling

Dilated cardiomyopathy (DCM) as a consequence of viral myocarditis is a worldwide cause of morbidity and death. The deposition of matrix proteins, such as collagen, in the course of ongoing viral myocarditis results in cardiac remodeling and finally in cardiac fibrosis, the hallmark of DCM. To identify mediators of virus-induced cardiac fibrosis, microarray analysis was conducted in a murine model of chronic coxsackievirus B3 (CVB3) myocarditis. By this attempt, we identified connective tissue growth factor (CTGF) as a novel factor highly expressed in infected hearts. Further investigations by quantitative reverse transcription polymerase chain reaction and Western blot analysis confirmed a strong induction of cardiac CTGF expression in the course of CVB3 myocarditis. By in situ hybridization and immunohistochemistry, basal CTGF messenger ribonucleic acid (mRNA) and protein expression were confined in noninfected control hearts mainly to endothelial cells, whereas in CVB3-infected hearts, also numerous fibroblasts were found to express CTGF. Regulation of CTGF is known to be basically mediated by transforming growth factor (TGF)-beta. In the course of CVB3 myocarditis, CTGF upregulation coincided with increased cardiac TGF-beta and procollagen type I mRNA expression, preceding the formation of fibrotic lesions. In in vitro experiments, we found that downregulation of CVB3 replication by means of small interfering RNAs (siRNAs) reverses the upregulation of CTGF mRNA expression. In contrast, downregulation of CTGF by siRNA molecules did not significantly reduce viral load, indicating that CTGF is not essential for CVB3 life cycle. The significantly enhanced transcript levels of TGF-beta, CTGF, and procollagen type I in cultivated CVB3-infected primary cardiac fibroblasts substantiate the role of fibroblasts as a relevant cell population in cardiac remodeling processes. We conclude that CTGF is a crucial molecule in the development of fibrosis in ongoing enteroviral myocarditis. Thus, downregulation of cardiac CTGF expression may open novel therapeutic approaches counteracting the development of cardiac fibrosis and subsequent heart muscle dysfunction.

Topics: Animals; Collagen Type I; Connective Tissue Growth Factor; Cytokines; Disease Models, Animal; Endothelial Cells; Enterovirus Infections; Fibroblasts; Mice; Myocarditis; Myocardium; RNA, Messenger; RNA, Small Interfering; Transforming Growth Factor beta

Cardiac fibrosis and inflammation are major pathologic conditions that result from viral myocarditis. Connective tissue growth factor (CTGF) stimulates fibroblast proliferation and induces production of extracellular matrix molecules. We studied the correlation between CTGF and cardiac fibrosis in an acute Coxsackievirus B3 (CVB3) myocarditis animal model. Eight-week-old BALB/c mice were infected intraperitoneally with 10(4) plaque forming units (PFU) of CVB3. Myocardial inflammation peaked on day 7 and decreased markedly by day 14 post-infection (pi); cardiac fibrosis was noted from day 7 and peaked on day 14. By contrast, CTGF was weakly expressed by the interstitial cells in uninfected control hearts and also in the hearts of day 3 pi. CTGF expression measured by real-time PCR was elevated on day 3 and peaked on day 7 pi. TGF-beta expression peaked at day 7 pi. The cell type of CTGF expression changed from interstitial cells to myocytes after virus infection. On day 7, CTGF was strongly expressed by myocytes and inflammatory cells surrounding calcified necrotic areas. In addition, cardiac myocytes expressed CTGF on day 14. Our results, based on an acute CVB3 model of myocarditis, provide evidence that CTGF may mediate the development of fibrosis after viral myocarditis, and that the cells expressed CTGF changes during the course of viral myocarditis.

Topics: Acute Disease; Animals; Base Sequence; Collagen Type I; Connective Tissue Growth Factor; Coxsackievirus Infections; DNA Primers; Enterovirus B, Human; Female; Fibrosis; Gene Expression; Immediate-Early Proteins; Immunohistochemistry; In Situ Hybridization; Intercellular Signaling Peptides and Proteins; Mice; Mice, Inbred BALB C; Myocarditis; Polymerase Chain Reaction; RNA, Messenger; Tissue Distribution; Transforming Growth Factor beta

Our aim was to assess whether adrenomedullin (AM), a potent vasodilator peptide with a variety of cardioprotective effects, has a therapeutic potential for the treatment of acute myocarditis in a rat model.. One week after myosin injection, rats received a continuous infusion of AM or vehicle for 2 weeks, and pathological and physiological investigations were performed.. AM treatment significantly reduced the infiltration of inflammatory cells in myocarditic hearts, and decreased the expressions of macrophage chemoattractant protein-1, matrix metalloproteinase-2 and transforming growth factor-beta. Myocardial edema indicated by increased heart weight to body weight ratio and wall thickness was attenuated by AM infusion (5.7+/-0.5 vs. 6.5+/-0.4 g/kg, and 1.9+/-0.3 vs. 2.8+/-0.5 mm, respectively). Infusion of AM significantly improved left ventricular maximum dP/dt and fractional shortening of myocarditic hearts (4203+/-640 vs. 3450+/-607 mm Hg/s, and 21.3+/-4.1 vs. 14.7+/-5.1%, respectively).. Infusion of AM improved cardiac function and pathological findings in a rat model of acute myocarditis. Thus, infusion of AM may be a potent therapeutic strategy for acute myocarditis.

Topics: Acute Disease; Adrenomedullin; Animals; Biomarkers; Blotting, Western; Chemokine CCL2; Echocardiography; Edema; Heart Rate; Immunohistochemistry; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Myocarditis; Myocardium; Myosins; Neovascularization, Physiologic; Rats; Rats, Inbred Lew; Reverse Transcriptase Polymerase Chain Reaction; Transforming Growth Factor beta

To investigate the effect of astragaloside (Astr), one of the active components of the Chinese medical herb Astragulus membranaceus, on cardiac fibrosis in chronic myocarditis and its relevant mechanisms.. Eighty mice were randomized into 3 groups, the control group (n=20), the model group (n=30) and the Astr group (n=30). Mice in the model group and the Astr group were monthly intraperitoneally inoculated with CVB3, but to the control group equal amount of culture fluid was given instead. Mice in the control and the model group were fed with drinking water while those in the Astr group with drinking water containing Astr-sodium carboxymethycellulose at a concentration of 300 mg/L. All the survived mice were sacrificed 3 months later. Heart tissue of mice was stained by picrosirius red for calculating collagen volume fraction (CVF) with an automatic image analysis system. Expressions of transforming growth factor beta1 (TGF-beta1), platelet derived growth factor (PDGF), matrix metalloproteinase 1 (MMP-1), tissue inhibitor of metalloproteinase 1 (TIMP-1), MMP-13 and MMP-14 in heart tissue were detected by Western blot analysis.. As compared with the model group, in the Astr group, the mortality and CVF were significantly lower (53.3% vs. 23.3%, chi2 = 4.23, P < 0.05), and (17.4 +/- 1.2% vs. 8.6 +/- 0.9%, chi2 = 5.38, P < 0.05), respectively. As compared with the control group, Western blot analysis showed that expression of TGF-beta1 was decreased, MMP-1 and TIMP-1 were down-regulated, while expressions of MMP-13 and MMP-14 were up-regulated after Astr treatment.. Astr could lower the mortality and alleviate the myocardial fibrosis of mice with chronic myocarditis. Its antifibrotic effect might be realized by way of inhibiting TGF-beta1 expression and up-regulating the expressions of MMP-13 and MMP-14 in the heart tissues.

Topics: Animals; Blotting, Western; Chronic Disease; Coxsackievirus Infections; Drugs, Chinese Herbal; Endomyocardial Fibrosis; Male; Matrix Metalloproteinase 13; Matrix Metalloproteinase 14; Mice; Mice, Inbred BALB C; Myocarditis; Random Allocation; Saponins; Transforming Growth Factor beta; Triterpenes

Postinfarction cardiac repair is regulated through timely activation and repression of inflammatory pathways, followed by transition to fibrous tissue deposition and formation of a scar. The transforming growth factor-beta/Smad3 pathway is activated in healing infarcts and may regulate cellular events critical for the inflammatory and the fibrotic responses.. We examined the effects of Smad3 gene disruption on infarct healing and the pathogenesis of cardiac remodeling. In the absence of injury, Smad3-null hearts had comparable function to and similar morphology as wild-type hearts. Smad3-null animals had suppressed peak chemokine expression and decreased neutrophil recruitment in the infarcted myocardium but showed timely repression of inflammatory gene synthesis and resolution of the inflammatory infiltrate. Although myofibroblast density was higher in Smad3-null infarcts, interstitial deposition of collagen and tenascin-C in the remodeling myocardium was markedly reduced. Compared with wild-type animals, Smad3-/- mice exhibited decreased dilative remodeling and attenuated diastolic dysfunction; however, infarct size was comparable between groups. Transforming growth factor-beta-mediated induction of procollagen type III and tenascin-C in isolated cardiac fibroblasts was dependent on Smad3, which suggests that decreased fibrotic remodeling in infarcted Smad3-null hearts may be due to abrogation of the profibrotic transforming growth factor-beta responses.. Smad3 loss does not alter the time course of resolution of inflammation in healing infarcts, but it prevents interstitial fibrosis in the noninfarcted myocardium and attenuates cardiac remodeling. Thus, the Smad3 cascade may be a promising therapeutic target for the treatment of myocardial infarction.

Topics: Animals; Cells, Cultured; Chemokines; Collagen; Diastole; Fibroblasts; Fibrosis; Matrix Metalloproteinase 1; Mice; Mice, Knockout; Myocardial Infarction; Myocardial Reperfusion; Myocarditis; Myocardium; Neutrophils; RNA, Messenger; Signal Transduction; Smad2 Protein; Smad3 Protein; Survival Rate; Tissue Inhibitor of Metalloproteinases; Transforming Growth Factor beta; Ventricular Remodeling

To explore the relation among apoptosis of myocardial cell and the expression of TGF-beta1 in VMC.. In the experiment, Viral myocarditis (VMC) in BALB/C mouse was obtained by inculating herpes simplex virus I type into abdominal cavity. The rate of VMC was 91.67% after 3 - 35 days of virus infection. The apoptosis (78.33%) and expression of TGF-beta1 (81.76%) were found in the myocardium of infected mouse by TUNEL and immunohistochemical method and electron microscope. AI of myocardial cell was 34.14+/-11.56 - 26.14+/-10.2.. Apoptosis and expression of TGF-beta1 may participate in occurrence and development of VMC.

Topics: Animals; Apoptosis; Herpes Simplex; Immunohistochemistry; In Situ Nick-End Labeling; Male; Mice; Mice, Inbred BALB C; Microscopy, Electron; Myocarditis; Myocardium; Simplexvirus; Transforming Growth Factor beta

To explore the effects of adenovirus vector-mediated gene transfer of CTLA4Ig fusion protein on CD4+CD25+ T cells in experimental autoimmune myocarditis (EAM).. EAM was induced by porcine cardiac myosin as previously described. Adenovirus vector-mediated CTLA4Ig gene was administrated intravenously in EAM rats on days 1, 4 and 7, with EGFP as control. On day 21, myocardium histopathology was examined and CD4+CD25+ T cells were isolated. Proliferation and suppression assays were used to evaluate the suppressive capacity of CD4+CD25+ T cells in vitro. Relative mRNA level of Foxp3 and TGF-beta was determined by quantitative real-time RT-PCR; expression of CTLA-4, B7-1 and B7-2 protein was compared with Western blot in CD4+CD25+ Tregs.. Severe inflammatory lesions were observed in the hearts of EGFP-treated EAM rats and the untreated ones, while Ad-CMV-CTLA4Ig alleviated the myocarditis histologically. Adenovirus vector-mediated CTLA4Ig gene transfer up-regulated the proportion of CD4+CD25+ Tregs significantly. T cell proliferation was greatly inhibited in the CTLA4Ig group compared with the untreated and EGFP-treated groups in vitro. CTLA-4 and B7-2 proteins were down-regulated in the CTLA4Ig group, Foxp3 and TGF-beta mRNA was up-regulated significantly by CTLA4Ig treatment.. Adenovirus vector-mediated CTLA4Ig gene transfer alleviated inflammation in EAM, one of the potential mechanisms is up-regulation of CD4+CD25+ Tregs.

Topics: Abatacept; Adenoviridae; Animals; Autoimmune Diseases; B7-1 Antigen; B7-2 Antigen; Blotting, Western; CD4 Antigens; Cell Proliferation; Forkhead Transcription Factors; Genetic Therapy; Genetic Vectors; Humans; Immunoconjugates; Lymphocyte Activation; Male; Myocarditis; Myocardium; Rats; Rats, Inbred Lew; Receptors, Interleukin-2; RNA, Messenger; T-Lymphocytes, Regulatory; Transforming Growth Factor beta

Clinical myocarditis is a precursor to dilated cardiomyopathy and a principal cause of heart failure. Nearly 30% of all recently diagnosed cases of myocarditis are attributable to infection with coxsackie B virus (CBV), the most frequently associated pathogen. CBV initially replicates in the pancreas and quickly spreads to the heart, inducing chronic autoimmunity. To determine whether immunosuppressive cytokines could act to limit the extent of autoimmunity to the heart, we infected transgenic mice that express immunosuppressive cytokines in the pancreas. Herein, we demonstrate that transgenic expression of transforming growth factor-beta (1) (TGF-beta) within the pancreatic beta cells prevented mice from developing autoimmune myocarditis after CBV infection. In contrast, transgenic expression of interleukin-4 did not inhibit virus-mediated heart disease. Furthermore, we show that TGF-beta expression reduced viral replication while promoting the recruitment of macrophages into the pancreas. These results illustrate the benefit of TGF-beta in controlling not only viral replication, but also CBV-mediated autoimmunity.

Topics: Animals; Autoimmune Diseases; Coxsackievirus Infections; Down-Regulation; Enterovirus; Female; Insulin-Secreting Cells; Macrophages; Male; Mice; Mice, Inbred NOD; Mice, Transgenic; Models, Animal; Myocarditis; Pancreas; Transforming Growth Factor beta; Virus Replication

Aldosterone blockade reduces morbidity and mortality in patients with heart failure. We studied the effects of eplerenone, a novel aldosterone blocker, on the progression of left ventricular dysfunction and remodeling in rats with dilated cardiomyopathy after autoimmune myocarditis. Twenty-eight days after immunization, the surviving Lewis rats were randomized to 1 month's oral treatment with low-dose eplerenone (group L), high-dose eplerenone (group H) or vehicle (group V). Five of 15 (33%) rats in group V and 3 of 15 (20%) rats in group L died during the course of treatment. High-dose eplerenone significantly reduced cardiomyocyte hypertrophy, heart weight and heart weight to body weight ratio. Eplerenone improved left ventricular function in a dose-dependent manner. Central venous pressure and left ventricular end-diastolic pressure were lower, and +/-dP/dt and fractional shortening were higher in group H than group V. Eplerenone also attenuated myocardial fibrosis and reduced left ventricular mRNA expressions of TGF-beta(1) and collagen-III. Our results indicate that treatment with eplerenone improved left ventricular dysfunction and attenuated left ventricular remodeling in rats with heart failure.

Topics: Animals; Autoimmune Diseases; Cardiomyopathy, Dilated; Collagen Type III; Dose-Response Relationship, Drug; Electrocardiography; Eplerenone; Fibrosis; Hemodynamics; Male; Mineralocorticoid Receptor Antagonists; Myocarditis; Myocardium; Rats; Rats, Inbred Lew; RNA, Messenger; Spironolactone; Transforming Growth Factor beta; Ventricular Dysfunction, Left; Ventricular Remodeling

We examined effects of an angiotensin-II receptor blockers, candesartan cilexetil, in rats with dilated cardiomyopathy after autoimmune myocarditis. Candesartan cilexetil showed angiotensin-II blocking action in a dose-dependent manner in rats with dilated cardiomyopathy. Twenty-eight days after immunization, surviving Lewis rats were divided into four groups and given candesartan cilexetil at 0.05 mg/kg, 0.5 mg/kg or 5 mg/kg per day (Group-C0.05, n = 15, Group-C0.5, n = 15 and Group-C5, n = 15, respectively) or vehicle alone (Group-V, n = 15). After oral administration for 1 month, the left ventricular end-diastolic pressure and heart weight/body weight ratio were lower in Group-C0.05 (13.3+/-1.1 mmHg and 3.7+/-0.2 g/kg, respectively), in Group-C0.5 (8.0+/-0.9 mmHg and 3.3+/-0.1 g/kg, respectively) and in Group-C5 (5.5+/-1 mmHg and 3.1+/-0.1 g/kg, respectively) than in Group-V (13.5+/-1.0 mmHg and 3.8+/-0.2 g/kg, respectively). The area of myocardial fibrosis was also lower in Group-C0.05 (25+/-3%), in Group-C0.5 (20+/-3%), and in Group-C5 (12+/-1%) than in Group-V (32+/-4%). Furthermore, expressions of transforming growth factor-beta1 and collagen-III mRNA were suppressed in Group-C0.05 (349+/-23% and 395+/-22%, respectively), Group-C0.5 (292+/-81% and 364+/-42%, respectively) and in Group-C5 (204+/-63% and 259+/-33%, respectively) compared with those in Group-V (367+/-26% and 437+/-18%, respectively). These results suggest that candesartan cilexetil can improve the function of inefficient heart.

Topics: Angiotensin II; Angiotensin Receptor Antagonists; Animals; Autoimmune Diseases; Benzimidazoles; Biphenyl Compounds; Blood Pressure; Cardiomyopathy, Dilated; Cardiotonic Agents; Collagen Type III; Male; Myocarditis; Myocardium; Rats; Rats, Inbred Lew; RNA, Messenger; Tetrazoles; Transforming Growth Factor beta; Transforming Growth Factor beta1; Up-Regulation

Dilated cardiomyopathy (DCM) is a major cause of morbidity and mortality. Occurrence of myocardial fibrosis is an important event in the ventricular remodeling process, which takes place during DCM. Mast cells are well known inflammatory cells implicated in various biological phenomena. The involvement of mast cells in the development of myocardial fibrosis of DCM in rats after autoimmune myocarditis remains unknown. Nine-week-old male Lewis rats were immunized with cardiac myosin and divided into vehicle treated (group V) and disodium cromoglycate (DSCG), a mast cell stabilizer (24 mg/kg i.p.) treated (group DSCG) groups. The animals were sacrificed after 60 d of immunization. The myocardium was excised and preserved for histopathology and protein analysis. Myocardial levels of transforming growth factor (TGF) beta1 and collagen-III were quantified. Staining of mast cells was performed by toluidine blue. A significant correlation was obtained between myocardial fibrosis and cardiac mast cell density. DSCG reduced myocardial fibrosis besides preventing infiltration and degranulation of mast cells. Our findings confirm the active participation of mast cells in the progression of myocardial fibrosis in rats with postmyocarditis DCM.

Topics: Animals; Biomarkers; Blotting, Western; Cardiomyopathy, Dilated; Cell Degranulation; Collagen Type III; Coloring Agents; Cromolyn Sodium; Fibrosis; Immunohistochemistry; Male; Mast Cells; Myocarditis; Rats; Rats, Inbred Lew; Transforming Growth Factor beta

The cardioprotective properties of pranidipine were studied in a rat model of heart failure after autoimmune myocarditis. Twenty-eight days after immunization the surviving rats were divided into three groups and received oral treatment of 0.03 mg/kg/day (group 0.03) or 0.3 mg/kg/day (group 0.3) of pranidipine or vehicle (group V) for 1 month. High-dose pranidipine (group 0.3) improved the survival rate, and significantly reduced heart weight, heart weight to body weight ratio, myocardial fibrosis, central venous pressure and left ventricular end-diastolic pressure than low-dose pranidipine (group 0.03) and group V. Pranidipine at high dose also decreased the left ventricular systolic and diastolic dimensions, and increased fractional shortening compared with group V. The increase in level of TGF-beta1 and collagen-III mRNA were suppressed by pranidipine in a dose-dependent manner. Our results indicated that pranidipine has cardioprotective effects on heart failure, and that the beneficial effect can be partly explained by attenuation of fibrotic response through suppression of TGF-beta1 and collagen-III mRNA expression, and regression of myocyte hypertrophy.

Topics: Animals; Blood Pressure; Calcium Channel Blockers; Dihydropyridines; Heart Failure; Heart Rate; Male; Myocarditis; Rats; Rats, Inbred Lew; Transforming Growth Factor beta; Ventricular Dysfunction, Left; Ventricular Remodeling

Inflammatory fibrosis is a characteristic feature of myocarditis, dilated cardiomyopathy (DCM), and congestive heart failure. Th1-type immune responses, mediated by interleukin (IL)-12-induced interferon (IFN)-gamma, are believed to exacerbate autoimmune diseases including myocarditis. In this study, we examined the effect of IL-12R beta 1 and IFN-gamma deficiency on the development of chronic CB3-induced myocarditis using knockout mice. We found increased chronic CB3-induced myocarditis (14.1 to 43.1%, P < 0.001); pericarditis (1.5 to 7.6%, P < 0.001); fibrosis (9.7 to 27.4%, P < 0.05); and the profibrotic cytokines transforming growth factor-beta(1), IL-1 beta, and IL-4 in the hearts of IFN-gamma-deficient mice. All mice infected with CB3 developed DCM, but IFN-gamma-deficient mice developed a fibrous, adhesive pericarditis associated with increased numbers of degranulating mast cells (MCs) in the pericardium (26.6 to 45.9%, P < 0.01), increased histamine levels (716 to 1930 ng/g of heart, P < 0.01), and reduced survival (100 to 43%). In contrast, IL-12R beta 1 deficiency did not significantly alter the development of chronic myocarditis. Thus, IFN-gamma protects against the development of severe chronic myocarditis, pericarditis, and DCM after CB3 infection by reducing MC degranulation, fibrosis, and the profibrotic cytokines transforming growth factor-beta(1), IL-1 beta, and IL-4 in the heart.

Topics: Animals; Cardiomyopathy, Dilated; Cell Degranulation; Chronic Disease; Enterovirus B, Human; Enterovirus Infections; Heart; Histamine; Interferon-gamma; Interleukin-1; Interleukin-4; Mast Cells; Mice; Mice, Inbred BALB C; Mice, Knockout; Myocarditis; Myocardium; Receptors, Interleukin; Receptors, Interleukin-12; Transforming Growth Factor beta; Transforming Growth Factor beta1

The cardioprotective properties of quinapril, an angiotensin-converting enzyme inhibitor, were studied in a rat model of dilated cardiomyopathy. Twenty-eight days after immunization of pig cardiac myosin, four groups rats were given 0.2 mg/kg (Q0.2, n = 11), 2 mg/kg (Q2, n = 11) or 20 mg/kg (Q20, n = 11) of quinapril or vehicle (V, n = 15) orally once a day. After 1 month, left ventricular end-diastolic pressure (LVEDP), +/- dP/dt, area of myocardial fibrosis, and myocardial mRNA expression of transforming growth factor (TGF)-beta1, collagen-III and fibronectin were measured. Four of 15 (27%) rats in V and two of 11 (18%) in Q0.2 died. None of the animals in Q2 or Q20 died. The LVEDP was higher and +/- dP/dt was lower in V (14.1 +/- 2.0 mmHg and +2409 +/- 150/-2318 +/- 235 mmHg/sec) than in age-matched normal rats (5.0 +/- 0.6 mmHg and +6173 +/- 191/-7120 +/- 74 mmHg/ sec; all p < 0.01). After quinapril treatment, LVEDP was decreased and +/- dP/dt was increased in a dose-dependent manner (10.8 +/- 1.8 mmHg and +3211 +/- 307/-2928 +/- 390 mmHg/sec in Q0.2, 9.4 +/- 1.5 mmHg and +2871 +/- 270/-2966 +/- 366 mmHg/sec in Q2, and 6.6 +/- 1.5 mmHg, and +3569 +/- 169/-3960 +/- 203 mmHg/sec in Q20). Increased expression levels of TGF-beta1, collagen-III and fibronectin mRNA in V were reduced in Q20. Quinapril improved survival rate and cardiac function in rats with dilated cardiomyopathy after myocarditis. Furthermore, myocardial fibrosis was regressed and myocardial structure returned to nearly normal in animals treated with quinapril.

Topics: Administration, Oral; Angiotensin-Converting Enzyme Inhibitors; Animals; Blood Pressure; Cardiomyopathy, Dilated; Collagen Type III; Dose-Response Relationship, Drug; Fibronectins; Fibrosis; Gene Expression; Heart Function Tests; Male; Myocarditis; Quinapril; Rats; Rats, Inbred Lew; RNA, Messenger; Survival Rate; Tetrahydroisoquinolines; Time Factors; Transforming Growth Factor beta; Transforming Growth Factor beta1; Ventricular Function, Left; Ventricular Pressure

Experimental autoimmune myocarditis (EAM) in rats is an animal model of human giant cell myocarditis and postmyocarditis dilated cardiomyopathy. As the heart consumes large amounts of energy, heart diseases such as myocarditis and dilated cardiomyopathy are associated with abnormal fatty acid metabolism. Peroxisome proliferator-activated receptor alpha (PPARalpha) is a regulator of the oxidative degradation of fatty acids. To investigate the role of PPARalpha in EAM, fenofibrate (a PPARalpha activator) was administered to rats with EAM for 4 weeks. Reductions in the ratios of both ventricular weight to body weight and the area of inflammatory lesions to the total area of heart sections were observed in fenofibrate-treated rats when compared with controls. Fenofibrate ameliorated changes in serum albumin and sialic acid, which are markers of inflammation. Cardiac expression of interleukin-10 (IL-10) mRNA was more pronounced in the fenofibrate group than in the control group (1.3 +/- 0.2 vs 0.7 +/- 0.1; p < 0.01), and the area of intact myocardium correlated with the IL-10 mRNA level (p = 0.0297, r = 0.620). We suggest that PPARalpha activators may prevent the progression of myocarditis through increased expression of the gene encoding the anti-inflammatory cytokine IL-10, although the mechanisms involved remain to be determined.

Topics: Animals; Autoimmune Diseases; Disease Models, Animal; Fatty Acids; Fenofibrate; Gene Expression; Hypolipidemic Agents; Interleukin-1; Interleukin-10; Male; Myocarditis; Myocardium; Rats; Rats, Inbred Lew; Receptors, Cytoplasmic and Nuclear; RNA, Messenger; Transcription Factors; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

The cardioprotective effects of quinapril, an angiotensin-converting enzyme inhibitor, were studied in a rat model of heart failure. Twenty-six rats were divided into two groups: one given 20 mg/kg/day quinapril (n = 11), and controls given 0.5% methylcellulose (n = 15). After oral administration for 1 month, quinapril reduced heart weight (from 1.28+/-0.05 to 0.87+/-0.02 g; p < 0.05) without changing body weight. Quinapril lowered left ventricular end-diastolic pressure (from 14.1+/-2.0 to 6.6+/-1.5 mmHg; p < 0.05) and central venous pressure (from 2.7+/-0.9 to 0.7+/-0.4 mmHg), and increased +/- dP/dt (from +2409+/-50 to +3569+/-169 mmHg/s, and from -2318+/-235 to -3960+/-203 mmHg/s; both p < 0.01). The area of myocardial fibrosis was markedly reduced by quinapril (6+/-3%) as compared with controls (29+/-6%; p < 0.01). Expression of transforming growth factor (TGF)-beta1 mRNA was markedly increased in controls as compared with age-matched normal rats. The increase in level of TGF-beta1 mRNA was significantly suppressed by quinapril (from 17.1+/-6.2 to 9.00+/-2.40; p < 0.05). These observations indicated that quinapril has cardioprotective effects on heart failure, and that the beneficial effects may be partly explained by attenuation of fibrotic response through suppression of TGF-beta1 mRNA expression.

Topics: Administration, Oral; Angiotensin-Converting Enzyme Inhibitors; Animals; Disease Progression; Heart Failure; Isoquinolines; Male; Myocarditis; Quinapril; Rats; Rats, Inbred Lew; RNA, Messenger; Tetrahydroisoquinolines; Transforming Growth Factor beta; Transforming Growth Factor beta1

To investigate the tissue repair of acute viral myocarditis, and to explore the diagnostic method of slight viral myocarditis in forensic pathology. Slight viral myocarditis model was induced in Balb/c murine by CVB3. Collagen proliferation in myocardium of mice with myocarditis was observed by special staining. The hearts of mice and human(9 cases) with myocarditis were studied LSAB-immunohistochemically with anti-TGF-beta 1 antibody. In the study, the proliferation of collagen was seen in myocardium in acute viral myocarditis. Generous expression of TGF-beta 1 was found in the myocardium of mice and human with myocarditis. The quantity of collagen proliferation and expression of TGF-beta 1 was positive correlation. It is concluded that the tissue repair exists in acute viral myocarditis and that positive staining of myocardium for TGF-beta 1 is a sensitive index of myocardial damage and tissue repair.

Topics: Animals; Collagen; Coxsackievirus Infections; Humans; Immunohistochemistry; Mice; Mice, Inbred BALB C; Myocarditis; Myocardium; Transforming Growth Factor beta

Expression of Fas ligand (FasL) renders certain tissues immune privileged, but its expression in other tissues can result in severe neutrophil infiltration and tissue destruction. The consequences of enforced FasL expression in striated muscle is particularly controversial. To create a stable reproducible pattern of cardiomyocyte-specific FasL expression, transgenic (Tg) mice were generated that express murine FasL specifically in the heart, where it is not normally expressed. Tg animals are healthy and indistinguishable from nontransgenic littermates. FasL expression in the heart does result in mild leukocyte infiltration, but despite coexpression of Fas and FasL in Tg hearts, neither myocardial tissue apoptosis nor necrosis accompanies the leukocyte infiltration. Instead of tissue destruction, FasL Tg hearts develop mild interstitial fibrosis, functional changes, and cardiac hypertrophy, with corresponding molecular changes in gene expression. Induced expression of the cytokines TNF-alpha, IL-1beta, IL-6, and TGF-beta accompanies these proinflammatory changes. The histologic, functional, and molecular proinflammatory consequences of cardiac FasL expression are transgene-dose dependent. Thus, coexpression of Fas and FasL in the heart results in leukocyte infiltration and hypertrophy, but without the severe tissue destruction observed in other examples of FasL-directed proinflammation. The data suggest that the FasL expression level and other tissue-specific microenvironmental factors can modulate the proinflammatory consequences of FasL.

Topics: Age Factors; Animals; Apoptosis; Cardiomegaly; Cell Size; Cytokines; Fas Ligand Protein; fas Receptor; Gene Dosage; Membrane Glycoproteins; Mice; Mice, Transgenic; Myocarditis; Transforming Growth Factor beta

This study was designed to examine whether myocarditis induced in a mouse model can be effectively suppressed by nasal administration of cardiac myosin (CM).. Myocarditis in humans often follows viral infection and is accompanied by evidence of an autoimmune response to CM. Treatment has been hampered by the fact that measures undertaken to reduce the autoimmune response often enhance the viral infection. Delivery of antigen via nasal route has been shown to induce antigen-specific tolerance and suppress certain autoimmune diseases in animal models.. Myocarditis was induced in A/J mice by two subcutaneous injections of CM emulsified in complete Freund's adjuvant. Nasal instillation of CM (200 microg/mouse) or vehicle buffer was carried out three days before the first subcutaneous injection (day -3). The effect of nasal instillation of CM on cardiac histopathology, cytokine production by splenocytes, and antibody response was examined three weeks after the first subcutaneous injection (day 21).. Nasal administration of CM effectively reduced the severity of myocarditis. Consistent with the histological findings, the levels of interleukin-2 (IL-2), tumor necrosis factor-alpha, and IL-1beta produced by splenocytes in response to CM were significantly decreased. In addition, the serum levels of IgE and IgG1 anti-myosin antibodies were suppressed. However, the levels of transforming growth factor-beta (TGF-beta) and CM-specific IgA antibodies were not affected.. Taken together, our results do not support active suppression through upregulation of TGF-beta, IL-4, and IL-10 as a mechanism of tolerance, but favor anergy or deletion of both Th1 and Th2 autoreactive T cells.

Topics: Administration, Intranasal; Animals; Autoimmune Diseases; Cytokines; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Female; Immune Tolerance; Mice; Mice, Inbred Strains; Myocarditis; Myosins; Transforming Growth Factor beta

Ribonuclease protection assay was used to demonstrate mRNA expression of several cytokines as well as inducible NO synthase (iNOS), constitutive endothelial NO synthase (cNOS) and perforin in the myocardium during the course of experimental autoimmune myocarditis (EAM) in rats. Interleukin 2 (IL-2) appeared in the initial inflammatory phase (day 14), subsided in the maximum inflammatory phase (day 19) and disappeared by the recovery phase (day 25). mRNA of IL-3 beta, interferon gamma INF-gamma and tumor necrosis factor alpha (TNF-alpha) were detected only in the maximum inflammatory phase and iNOS also appeared for several days at this time. In contrast. IL-10 mRNA was detected after the maximum inflammatory stage and persisted into the recovery phase (days 25-36). Although transforming growth factor beta 1 (TGF-beta 1) could be detected in all phases, the expression was markedly enhanced in the maximum inflammatory phase and gradually diminished (around day 36) to basal levels. Perforin mRNA was not detected at any point in the disease. Besides macrophages and CD4 T cells, a number of neutrophils were found in the myocardium especially at peak inflammatory stage. We suggest that antigen (Ag) primed Ag presenting cells or macrophages interact with T cells (Th1) to produce IL-2 and subsequent IFN-gamma, which further activates macrophages in the myocardium. Consequently, TNF-alpha and iNOS may inflict tissue damage to myocardium. It is also suggested that TGF-beta) and one representative Th2 cytokine, IL-10, help inhibit inflammation. These findings suggest that Th1 and Th2 cytokines are produced at different stages of EAM and modulate the inflammation and the course of EAM.

Topics: Animals; Autoimmune Diseases; CD4-Positive T-Lymphocytes; Cytokines; Disease Models, Animal; Interferon-gamma; Interleukin-1; Interleukin-2; Macrophages; Male; Membrane Glycoproteins; Microscopy, Fluorescence; Myocarditis; Myocardium; Nitric Oxide Synthase; Perforin; Pore Forming Cytotoxic Proteins; Rats; Rats, Inbred Lew; Ribonucleases; RNA, Messenger; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha