sirolimus and Myocarditis

Background Sarcoidosis is an inflammatory, granulomatous disease of unknown cause affecting multiple organs, including the heart. Untreated, unresolved granulomatous inflammation can lead to cardiac fibrosis, arrhythmias, and eventually heart failure. Here we characterize the cardiac phenotype of mice with chronic activation of mammalian target of rapamycin (mTOR) complex 1 signaling in myeloid cells known to cause spontaneous pulmonary sarcoid-like granulomas. Methods and Results The cardiac phenotype of mice with conditional deletion of the

Topics: Animals; Death, Sudden, Cardiac; Disease Models, Animal; Everolimus; Fibrosis; Humans; Mammals; Mechanistic Target of Rapamycin Complex 1; Mice; Multiprotein Complexes; Myocarditis; Sarcoidosis; Sirolimus; TOR Serine-Threonine Kinases; Tuberous Sclerosis Complex 2 Protein; Tumor Suppressor Proteins

Considering the efficacy of rapamycin in increasing lifespan and healthspan, attenuating the aging-dependent immunological decline, we compared the evolution of Trypanosoma cruzi infection and acute myocarditis in young and elderly mice untreated and chronically treated with this drug. Five groups were investigated: young uninfected and infected, elderly uninfected and infected with Trypanosoma cruzi untreated and treated with rapamycin (4 mg/kg every 3 days) from the 8th to the 96th week of age. Seven days after the last treatment, elderly mice were inoculated with T. cruzi. Young animals were infected at 8-weeks-old. Untreated elderly mice exhibited increase parasitemia, parasite load and myocarditis, which were associated to down-regulation in IL-2, IL-6, IFN-γ, TNF, anti-T. cruzi immunoglobulin G (IgG) total, IgG1 and IgG2a plasma levels, inducible nitric oxide synthase (iNOS) gene expression and nitric oxide (NO) cardiac production, as well as upregulation in Arginase-1 gene expression and arginase activity compared to young animals. These parameters were improved in rapamycin-pretreated elderly mice, which exhibited a better parasitological control, reduced heart inflammation and microstructural damage. These responses were associated with a better balance between Th1 and Th2 effectors similar to that observed in young animals, including an improved activation of Th1 cytokines and the iNOS pathway that positively regulates NO biosynthesis, contradicting the predominant activation of the arginase pathway in untreated elderly animals. Thus, our findings suggest that chronic pretreatment with rapamycin can attenuate immunosenescence in mice, contributing to prolong parasite resistance and attenuate acute myocarditis in elderly host challenged by T. cruzi.

Topics: Aging; Animals; Arginase; Chagas Disease; Mice; Myocarditis; Nitric Oxide; Nitric Oxide Synthase Type II; Sirolimus; Trypanosoma cruzi

Chagas disease affects millions of people mainly in Latin America and is a protozoan illness caused by the parasite Trypanosoma cruzi. Chagasic cardiomyopathy is the leading cause of mortality of infected patients, due to compromised electrical and mechanical cardiac function induced by tissue remodeling, especially fibrosis, and lymphocytic infiltration. Some cellular biochemical pathways can be protective to the heart, and we tested if the in vivo activation of the autophagic machinery by rapamycin could reduce parasite-induced myocarditis. Regarding the expression of LC3, an autophagy marker, we observed its upregulation in the cardiac tissue of infected untreated mice. However, after rapamycin treatment, an autophagy inducer, infected mice showed reduced electrical cardiac dysfunctions, myocarditis, cardiac damage, and reduced production of pro-inflammatory cytokines by the heart. On the other hand, the parasite's life cycle was not affected, and we observed no modulations in cardiac tissue or blood parasitemia. Our data indicate that, at least partially, autophagy induction controls inflammation in the heart¸ illustrating the complexity of the pathways that concur to the development of the infection.

Topics: Acute Disease; Animals; Chagas Disease; Male; Mice; Microtubule-Associated Proteins; Myocarditis; Sirolimus; Trypanosoma cruzi

Topics: Adult; Female; Fertilization in Vitro; Heart Transplantation; Humans; Immunosuppression Therapy; Immunosuppressive Agents; Mycophenolic Acid; Myocarditis; Sirolimus; Surrogate Mothers; TOR Serine-Threonine Kinases; Treatment Outcome; Troponin T

Adiponectin (APN), an adipose-derived adipokine, alleviates lipopolysaccharide (LPS)-induced injury in multiple organs including hearts although the underlying mechanism in endotoxemia remains elusive. This study was designed to examine the role of adiponectin in LPS-induced cardiac anomalies and inflammation as well as the underlying mechanism with a focus on autophagy - a conserved machinery for bulk degradation of intracellular components.. Wild-type (WT) and APN(-/-) mice were challenged with LPS (4mg/kg) or saline for 6h. Echocardiography, cardiomyocyte contractile and intracellular Ca(2+) properties were evaluated. Markers of autophagy, apoptosis and inflammation including LC3B, p62, Beclin1, AMPK, mTOR, ULK, Caspase 3, Bcl-2, Bax, TLR4, TRAF6, MyD88, IL-1B, TNFα, HMGB1, JNK and IκB were examined using Western blot or RT-PCR. Our results showed that LPS challenge reduced fractional shortening, compromised cardiomyocyte contractile capacity, intracellular Ca(2+) handling properties, apoptosis and inflammation, which were accentuated by adiponectin ablation. Adiponectin ablation unmasked the LPS-induced cardiac remodeling (left ventricular end systolic diameter) and prolongation of cell shortening. The detrimental effects of adiponectin ablation were associated with dampened autophagy in response to LPS through an AMPK-mTOR-ULK1-dependent mechanism. In vivo administration of AMPK activator AICAR or the autophagy inducer rapamycin effectively attenuated or obliterated LPS-induced and adiponectin deficiency-accentuated responses without affecting TLR4, TRAF6 and MyD88.. The findings suggest that AMPK and autophagy may play a permissive role in the adiponectin deficiency-exacerbated cardiac dysfunction, apoptosis and inflammation under LPS challenge possibly at the post-TLR4 receptor level.

Topics: Adiponectin; Aminoimidazole Carboxamide; AMP-Activated Protein Kinases; Animals; Autophagy; Autophagy-Related Protein-1 Homolog; Calcium; Calcium-Calmodulin-Dependent Protein Kinase Kinase; Cell Death; Disease Models, Animal; Endotoxemia; Lipopolysaccharides; Male; Mice; Mice, Knockout; Myocarditis; Myocardium; Myocytes, Cardiac; Ribonucleotides; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Ventricular Dysfunction

Topics: Coronary Restenosis; Diagnosis, Differential; Drug-Eluting Stents; Echocardiography; Follow-Up Studies; Humans; Immunosuppressive Agents; Male; Middle Aged; Myocarditis; Prosthesis Failure; Sirolimus; Tomography, X-Ray Computed

To observe the effeet of rapamycin, an inhibitor of mammalian target of rapamycin (mTOR), on mTOR and eukaryotic initiation factor-4E(eIF-4E)expression in coxsac-kievirus B3 (CVB3)-induced rat myocardial cells and to investigate the role of mTOR/eIF-4E signal pathway in viral myocarditis.. To construct a cell model of viral myocarditis with primary cultured myocardial cells. Myocardial cells infected by CVB3 were treated with 10 nmol/L rapamycin according to the cell toxicity test. The mTOR and eIF-4E expressions of cells were determined by RT-PCR and Western Blot.. Rapamycin inhibited the degeneration of CVB3-induced myocardial cells. Expressions of mTOR and eIF-4E mRNA or protein in CVB3-induced myocardial cells were significantly upregulated compared with the control group (P < 0.05), and rapamycin (10 nmol/L) inhibited the upregulation (P < 0.05).. Rapamycin can downregulate the expressions of mTOR and eIF-4E in CVB3-induced myocardial cells, suggesting that mTOR/eIF-4E signal transduction may play an important role in viral myocarditis.

Topics: Animals; Animals, Newborn; Coxsackievirus Infections; Enterovirus B, Human; Eukaryotic Initiation Factor-4E; Myocarditis; Myocytes, Cardiac; Protein Kinases; Rats; Rats, Sprague-Dawley; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

This study examined the effect of rapamycin, an inhibitor of mammalian target of rapamycin (mTOR), on eukaryotic initiation factor (eIF- 4E) expression in rat myocardial fibroblasts infected by Coxsackievirus B3 (CVB3) in order to identify the drug target for treatment of viral myocarditis.. Primary cultured rat myocardial fibroblasts were treated with CVB3 with multiplicity of infection (MOI=0.5 PFU/cell). The experiment consisted of four groups in which the cultured rat fibroblasts cells were treated with CVB3, rapamycin (10 nM) and CVB3 + rapamycin or placebo (control). Experimental model of CVB3-infected myocardial fibroblasts was confirmed by detection of CVB3 mRNA expression with RT-PCR and observation of morphological changes of the infected cells with microscopy. eIF-4E expression was determined by both RT-PCR and Western Blot methods.. Morphological changes were found in the fibroblasts treated with MOI 0.5 PFU/cell of CVB3 by transmission electron microscope and the viral particles were found in the cytoplasm. CVB3 mRNA was expressed in CVB3-infected fibroblasts after 1, 2, and 3 days after infection and 2 days after passage. The gray scale values of the eIF- 4E /beta -actin in the control, the CVB3, the rapamycin and the CVB3+rapamycin groups were 0.73 +/- 0.07, 0.87 +/- 0.03, 0.32 +/- 0.03 and 0.56 +/- 0.04 respectively detected by RT-PCR, and were 0.79 +/- 0.09, 1.35 +/- 0.12, 0.55 +/- 0.04, and 0.62 +/- 0.07 respectively detected by Western blot. EIF- 4E expression in the CVB3 group was higher than that in the control group. Both the rapamycin and the CVB3+rapamycin groups had lower eIF- 4E expression than the control and the CVB3 groups.. CVB3 can infect myocardial fibroblasts and up-regulate the eIF- 4E expression in rat myocardial fibroblasts. Rapamycin can inhibit eIF- 4E expression and may be a potential medicine for treatment of viral myocarditis. It was suspected that mTOR/eIF- 4E signal pathway in rat myocardial fibroblasts might play an important role in the pathogenesis of viral myocarditis.

Topics: Animals; Cells, Cultured; Enterovirus B, Human; Enterovirus Infections; Eukaryotic Initiation Factor-4E; Fibroblasts; Gene Expression Regulation; Myocarditis; Myocardium; Rats; Sirolimus

Myosin-induced autoimmune myocarditis in rats is a model of human dilated cardiomyopathy. Rapamycin is a potent immunosuppressant and specifically inactivates the mammalian target of rapamycin (mTOR). To examine the role of mTOR in autoimmune myocarditis, we administered rapamycin to rats immunized with cardiac myosin. Phosphorylation of p70 ribosomal S6 kinase 1 (S6K1), a target of mTOR, was increased by 6.9 fold in the heart tissue of myosin immunized rats. Rapamycin (2 mg/kg/day) completely suppressed S6K1 and S6 phosphorylation. The amount of interleukin-1beta, interferon-gamma, interleukin-2, or tumor necrosis factor-alpha mRNA in the heart tissue was markedly increased in myosin-immunized rats, and rapamycin significantly attenuated the cytokine gene expressions. Rapamycin improved the survival of the rats and preserved cardiac function. The plasma level of brain natriuretic peptide increased by 4.7 fold in myosin-immunized rats, and rapamycin attenuated the increase in plasma brain natriuretic peptide. The heart weight/tibial length ratio of vehicle-treated myosin-immunized rats was increased by 1.81 +/- 0.06 fold compared with vehicle-treated unimmunized rats, and rapamycin suppressed the increase in heart weight. Rapamycin decreased the cellular infiltration and fibrosis of the myocardium. The amount of phosphorylated S6 was increased in the infiltrating mononuclear cells in vehicle-treated myosin-immunized rats. Rapamycin significantly ameliorated myocardial injury and preserved cardiac function in a rat model of autoimmune myocarditis.

Topics: Animals; Autoimmunity; Cardiomyopathy, Dilated; Disease Models, Animal; Female; Gene Expression Regulation; Immunosuppressive Agents; Interferon-gamma; Interleukin-1; Interleukin-2; Myocarditis; Myosins; Natriuretic Peptide, Brain; Rats; Rats, Inbred Lew; Sirolimus; Treatment Outcome; Tumor Necrosis Factor-alpha