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Foxp3+ regulatory T cells (Treg cells) are the central component of peripheral immune tolerance. Whereas a dysregulated Treg cytokine signature has been observed in autoimmune diseases, the regulatory mechanisms underlying pro- and anti-inflammatory cytokine production are elusive. Here, we identify an imbalance between the cytokines IFN-γ and IL-10 as a shared Treg signature present in patients with multiple sclerosis and under high-salt conditions. RNA-sequencing analysis on human Treg subpopulations revealed ß-catenin as a key regulator of IFN-γ and IL-10 expression. The activated ß-catenin signature was enriched in human IFN-γ+ Treg cells, as confirmed in vivo with Treg-specific ß-catenin-stabilized mice exhibiting lethal autoimmunity with a dysfunctional Treg phenotype. Moreover, we identified prostaglandin E receptor 2 (PTGER2) as a regulator of IFN-γ and IL-10 production under a high-salt environment, with skewed activation of the ß-catenin-SGK1-Foxo axis. Our findings reveal a novel PTGER2-ß-catenin loop in Treg cells linking environmental high-salt conditions to autoimmunity.
Assuntos
Autoimunidade/imunologia , Inflamação/imunologia , Esclerose Múltipla Recidivante-Remitente/imunologia , Linfócitos T Reguladores/imunologia , beta Catenina/imunologia , Animais , Regulação da Expressão Gênica/imunologia , Humanos , Interferon gama/biossíntese , Interferon gama/imunologia , Interleucina-10/biossíntese , Interleucina-10/imunologia , Camundongos Endogâmicos C57BL , Receptores de Prostaglandina E Subtipo EP2/imunologia , Linfócitos T Reguladores/metabolismoRESUMO
Wnt signaling plays critical roles in development of various organs and pathogenesis of many diseases, and augmented Wnt signaling has recently been implicated in mammalian aging and aging-related phenotypes. We here report that complement C1q activates canonical Wnt signaling and promotes aging-associated decline in tissue regeneration. Serum C1q concentration is increased with aging, and Wnt signaling activity is augmented during aging in the serum and in multiple tissues of wild-type mice, but not in those of C1qa-deficient mice. C1q activates canonical Wnt signaling by binding to Frizzled receptors and subsequently inducing C1s-dependent cleavage of the ectodomain of Wnt coreceptor low-density lipoprotein receptor-related protein 6. Skeletal muscle regeneration in young mice is inhibited by exogenous C1q treatment, whereas aging-associated impairment of muscle regeneration is restored by C1s inhibition or C1qa gene disruption. Our findings therefore suggest the unexpected role of complement C1q in Wnt signal transduction and modulation of mammalian aging.
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Envelhecimento/metabolismo , Complemento C1q/metabolismo , Via de Sinalização Wnt , Animais , Complemento C1s/metabolismo , Humanos , Proteína-6 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Camundongos , Soro/metabolismoRESUMO
Torsade de pointes (TdP) occurred in a long QT syndrome type 3 (LQT3) patient after switching perospirone to blonanserin. We studied how their electropharmacological effects had induced TdP in the LQT3 patient. Perospirone hydrochloride (n = 4) or blonanserin (n = 4) of 0.01, 0.1, and 1 mg/kg, i.v. was cumulatively administered to the halothane-anesthetized dogs over 10 min. The low dose of perospirone decreased total peripheral vascular resistance, but increased heart rate and cardiac output, facilitated atrioventricular conduction, and prolonged J-Tpeakc. The middle dose decreased mean blood pressure and prolonged repolarization period, in addition to those observed after the low dose. The high dose further decreased mean blood pressure with the reduction of total peripheral vascular resistance; however, it did not increase heart rate or cardiac output. It tended to delay atrioventricular conduction and further delayed repolarization with the prolongation of Tpeak-Tend, whereas J-Tpeakc returned to its baseline level. Meanwhile, each dose of blonanserin decreased total peripheral vascular resistance, but increased heart rate, cardiac output and cardiac contractility in a dose-related manner. J-Tpeakc was prolonged by each dose, but Tpeak-Tend was shortened by the middle and high doses. These results indicate that perospirone and blonanserin may cause the hypotension-induced, reflex-mediated increase of sympathetic tone, leading to the increase of inward Ca2+ current in the heart except that the high dose of perospirone reversed them. Thus, blonanserin may have more potential to produce intracellular Ca2+ overload triggering early afterdepolarization than perospirone, which might explain the onset of TdP in the LQT3 patient.
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Doença do Sistema de Condução Cardíaco/fisiopatologia , Antagonistas de Dopamina/toxicidade , Sistema de Condução Cardíaco/efeitos dos fármacos , Síndrome do QT Longo/fisiopatologia , Antagonistas da Serotonina/toxicidade , Torsades de Pointes/induzido quimicamente , Potenciais de Ação/efeitos dos fármacos , Anestésicos Inalatórios , Animais , Agonistas dos Canais de Cálcio/toxicidade , Delírio/tratamento farmacológico , Cães , Relação Dose-Resposta a Droga , Eletrocardiografia , Feminino , Halotano , Sistema de Condução Cardíaco/metabolismo , Sistema de Condução Cardíaco/fisiopatologia , Humanos , Isoindóis , Pessoa de Meia-Idade , Modelos Animais , Piperazinas , Piperidinas , Bloqueadores dos Canais de Potássio/toxicidade , Distúrbios do Início e da Manutenção do Sono/tratamento farmacológico , Tiazóis , Torsades de Pointes/metabolismo , Torsades de Pointes/fisiopatologiaRESUMO
BACKGROUND: Since regenerative capacity of adult mammalian myocardium is limited, activation of the endogenous proliferative capacity of existing cardiomyocytes is a potential therapeutic strategy for treating heart diseases accompanied by cardiomyocyte loss. Recently, we performed a compound screening and developed a new drug named TT-10 (C11H10FN3OS2) which promotes the proliferation of murine cardiomyocytes via enhancement of YES-associated protein (YAP)-transcriptional enhancer factor domain (TEAD) activity and improves cardiac function after myocardial infarction in adult mice. METHODS AND RESULTS: To test whether TT-10 can also promote the proliferative capacity of human cardiomyocytes, we investigated the efficacy of TT-10 on human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes (hiPSCMs). The hiPSCs were established from monocytes obtained from healthy donors and cardiac differentiation was performed using a chemically defined protocol. As was observed in murine cardiomyocytes, TT-10 markedly promoted cell cycle activation and increased cell division of hiPSCMs. We then evaluated other effects of TT-10 on the functional properties of hiPSCMs by gene expression and cell motion analyses. We observed that TT-10 had no unfavorable effects on the expression of functional and structural genes or the contractile properties of hiPSCMs. CONCLUSIONS: Our results suggest that the novel drug TT-10 effectively activated the cell cycle of hiPSCMs without apparent functional impairment of myocardium, suggesting the potential of clinical usefulness of this drug.
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Ciclo Celular/efeitos dos fármacos , Células-Tronco Pluripotentes Induzidas/efeitos dos fármacos , Miócitos Cardíacos/efeitos dos fármacos , Bibliotecas de Moléculas Pequenas/farmacologia , Animais , Diferenciação Celular/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Humanos , Camundongos , Miocárdio/metabolismo , Miocárdio/patologia , Regeneração/efeitos dos fármacos , Regeneração/genéticaRESUMO
BACKGROUND: The heart responds to hemodynamic overload through cardiac hypertrophy and activation of the fetal gene program. However, these changes have not been thoroughly examined in individual cardiomyocytes, and the relation between cardiomyocyte size and fetal gene expression remains elusive. We established a method of high-throughput single-molecule RNA imaging analysis of in vivo cardiomyocytes and determined spatial and temporal changes during the development of heart failure. METHODS AND RESULTS: We applied three novel single-cell analysis methods, namely, single-cell quantitative PCR (sc-qPCR), single-cell RNA sequencing (scRNA-seq), and single-molecule fluorescence in situ hybridization (smFISH). Isolated cardiomyocytes and cross sections from pressure overloaded murine hearts after transverse aortic constriction (TAC) were analyzed at an early hypertrophy stage (2â¯weeks, TAC2W) and at a late heart failure stage (8â¯weeks, TAC8W). Expression of myosin heavy chain ß (Myh7), a representative fetal gene, was induced in some cardiomyocytes in TAC2W hearts and in more cardiomyocytes in TAC8W hearts. Expression levels of Myh7 varied considerably among cardiomyocytes. Myh7-expressing cardiomyocytes were significantly more abundant in the middle layer, compared with the inner or outer layers of TAC2W hearts, while such spatial differences were not observed in TAC8W hearts. Expression levels of Myh7 were inversely correlated with cardiomyocyte size and expression levels of mitochondria-related genes. CONCLUSIONS: We developed a new image-analysis pipeline to allow automated and unbiased quantification of gene expression at the single-cell level and determined the spatial and temporal regulation of heterogenous Myh7 expression in cardiomyocytes after pressure overload.
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Aorta/diagnóstico por imagem , Cardiomegalia/genética , Insuficiência Cardíaca/diagnóstico por imagem , Imagem Molecular/métodos , Cadeias Pesadas de Miosina/genética , Animais , Aorta/metabolismo , Aorta/patologia , Cardiomegalia/diagnóstico , Cardiomegalia/diagnóstico por imagem , Regulação da Expressão Gênica/genética , Coração/diagnóstico por imagem , Coração/fisiopatologia , Insuficiência Cardíaca/patologia , Hemodinâmica , Hibridização in Situ Fluorescente , Camundongos , Mitocôndrias/genética , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Cadeias Pesadas de Miosina/isolamento & purificação , RNA/genética , RNA/isolamento & purificação , Análise de Sequência de RNA , Imagem Individual de Molécula , Análise de Célula ÚnicaRESUMO
We investigated the electro-mechanical relationship of human iPS cell-derived cardiomyocyte sheets under arrhythmic condition, which was induced by digitalis intoxication along with the electrical train stimulation (n = 4). We adopted motion vector analysis by high-speed video microscopy and extracellular field potential recording by 64-microelectrode array system. The motion vector analysis uncovered local contractile events at resting phase, at which the field potential analysis showed no deflection in any cell sheet. Thus, motion vector analysis may provide supplemental information over field potential recording in detecting Ca2+-triggered arrhythmias, which may become a new strategy for assessing arrhythmic liability of test articles.
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Arritmias Cardíacas/fisiopatologia , Células-Tronco Pluripotentes Induzidas/fisiologia , Miócitos Cardíacos/fisiologia , Diferenciação Celular/fisiologia , Células Cultivadas , Humanos , MicroeletrodosRESUMO
We analyzed how the enhancement of net sarcoplasmic reticulum (SR) Ca2+ uptake may affect cardiac electrophysiological properties in vivo by using caldaret which can decrease SR diastolic Ca2+ leak, enhance SR Ca2+ reuptake and inhibit reverse-mode Na+/Ca2+ exchanger. Caldaret in doses of 0.5, 5 and 50 µg/kg was intravenously administered over 10 min to the halothane-anesthetized beagle dogs (n = 5), attaining pharmacologically active plasma concentration. The low and middle doses of caldaret increased the ventricular contraction, which could be explained by its on-target pharmacological activities. The high dose enhanced the sinus automaticity followed by its suppression in addition to the increase of the total peripheral resistance, which may be unfavorable for treating diastolic heart failure. The low and middle doses enhanced the atrioventricular conduction, which may have some potential for predisposing the atria to the onset of atrial fibrillation via an induction of mitral and/or tricuspid regurgitation. The middle and high doses of caldaret prolonged the ventricular effective refractory period without altering the intraventricular conduction or repolarization period, which may prevent the onset of ventricular arrhythmias. Thus, modulation of intracellular Ca2+ handling by caldaret can induce not only inotropic effect, but also various electrophysiological actions on the in situ heart.
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Benzenossulfonatos/farmacologia , Cálcio/administração & dosagem , Cardiotônicos/farmacologia , Piperazinas/farmacologia , Retículo Sarcoplasmático/efeitos dos fármacos , Animais , Arritmias Cardíacas/prevenção & controle , Benzenossulfonatos/administração & dosagem , Cálcio/metabolismo , Cardiotônicos/administração & dosagem , Cães , Relação Dose-Resposta a Droga , Técnicas Eletrofisiológicas Cardíacas , Feminino , Halotano/administração & dosagem , Átrios do Coração/efeitos dos fármacos , Átrios do Coração/metabolismo , Piperazinas/administração & dosagem , Retículo Sarcoplasmático/metabolismo , Trocador de Sódio e Cálcio/metabolismoRESUMO
CD36 is one of the important transporters of long-chain fatty acids (LCFAs) in the myocardium. We previously reported that CD36-deficient patients demonstrate a marked reduction of myocardial uptake of LCFA, while myocardial glucose uptake shows a compensatory increase, and are often accompanied by cardiomyopathy. However, the molecular mechanisms and functional role of CD36 in the myocardium remain unknown.The current study aimed to explore the pathophysiological role of CD36 in the heart. Methods: Using wild type (WT) and knockout (KO) mice, we generated pressure overload by transverse aortic constriction (TAC) and analyzed cardiac functions by echocardiography. To assess cardiac hypertrophy and fibrosis, histological and molecular analyses and measurement of ATP concentration in mouse hearts were performed.By applying TAC, the survival rate was significantly lower in KO than that in WT mice. After TAC, KO mice showed significantly higher heart weight-to-tibial length ratio and larger cross-sectional area of cardiomyocytes than those of WT. Although left ventricular (LV) wall thickness in the KO mice was similar to that in the WT mice, the KO mice showed a significant enlargement of LV cavity and reduced LV fractional shortening compared to the WT mice with TAC. A tendency for decreased myocardial ATP concentration was observed in the KO mice compared to the WT mice after TAC operation.These data suggest that the LCFA transporter CD36 is required for the maintenance of energy provision, systolic function, and myocardial structure.
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Antígenos CD36/genética , Proteínas de Transporte de Ácido Graxo/metabolismo , Miocárdio/metabolismo , Miócitos Cardíacos/metabolismo , Disfunção Ventricular Esquerda/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Antígenos CD36/fisiologia , Metabolismo Energético/fisiologia , Fibrose , Glucose/metabolismo , Hipertrofia Ventricular Esquerda/complicações , Hipertrofia Ventricular Esquerda/diagnóstico por imagem , Hipertrofia Ventricular Esquerda/fisiopatologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Miocárdio/patologia , Miócitos Cardíacos/patologia , Pressão/efeitos adversos , Disfunção Ventricular Esquerda/diagnóstico por imagem , Disfunção Ventricular Esquerda/fisiopatologia , Remodelação VentricularRESUMO
Cardiac fibrosis plays an important role in cardiac remodeling after myocardial infarction (MI). The molecular mechanisms that promote cardiac fibrosis after MI are well studied; however, the mechanisms by which the progression of cardiac fibrosis becomes attenuated after MI remain poorly understood. Recent reports show the role of cellular senescence in limiting tissue fibrosis. In the present study, we tested whether cellular senescence of cardiac fibroblasts (CFs) plays a role in attenuating the progression of cardiac fibrosis after MI. We found that the number of γH2AX-positive CFs increased up to day 7, whereas the number of proliferating CFs peaked at day 4 after MI. Senescent CFs were also observed at day 7, suggesting that attenuation of CF proliferation occurred simultaneously with the activation of the DNA damage response (DDR) system and the appearance of senescent CFs. We next cultured senescent CFs with non-senescent CFs and showed that senescent CFs suppressed proliferation of the surrounding non-senescent CFs in a juxtacrine manner. We also found that the blockade of DDR by Atm gene deletion sustained the proliferation of CFs and exacerbated the cardiac fibrosis at the early stage after MI. Our results indicate the role of DDR activation and cellular senescence in limiting cardiac fibrosis after MI. Regulation of cellular senescence in CFs may become one of the therapeutic strategies for preventing cardiac remodeling after MI.
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Senescência Celular/genética , Dano ao DNA/genética , Infarto do Miocárdio/patologia , Miócitos Cardíacos/metabolismo , Remodelação Ventricular/genética , Animais , Modelos Animais de Doenças , Fibroblastos/metabolismo , Fibroblastos/patologia , Fibrose/genética , Fibrose/metabolismo , Fibrose/patologia , Citometria de Fluxo , Marcação In Situ das Extremidades Cortadas , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Infarto do Miocárdio/genética , Infarto do Miocárdio/metabolismo , Miócitos Cardíacos/patologiaRESUMO
BACKGROUND: Fabry disease is an X-linked disease caused by mutations in α-galactosidase A (GLA); these mutations result in the accumulation of its substrates, mainly globotriaosylceramide (Gb3). The accumulation of glycosphingolipids induces pathogenic changes in various organs, including the heart, and Fabry cardiomyopathy is the most frequent cause of death in patients with Fabry disease. Existing therapies to treat Fabry disease have limited efficacy, and new approaches to improve the prognosis of patients with Fabry cardiomyopathy are required. METHODS AND RESULTS: We generated induced pluripotent stem cell (iPSC) lines from a female patient and her son. Each iPSC clone from the female patient showed either deficient or normal GLA activity, which could be used as a Fabry disease model or its isogenic control, respectively. Erosion of the inactivated X chromosome developed heterogeneously among clones, and mono-allelic expression of the GLA gene was maintained for a substantial period in a subset of iPSC clones. Gb3 accumulation was observed in iPSC-derived cardiomyocytes (iPS-CMs) from GLA activity-deficient iPSCs by mass-spectrometry and immunofluorescent staining. The expression of ANP was increased, but the cell surface area was decreased in iPS-CMs from the Fabry model, suggesting that cardiomyopathic change is ongoing at the molecular level in Fabry iPS-CMs. We also established an algorithm for selecting proper Gb3 staining that could be used for high-content analysis-based drug screening. CONCLUSIONS: We generated a Fabry cardiomyopathy model and a drug screening system by using iPS-CMs from a female Fabry patient. Drug screening using our system may help discover new drugs that would improve the prognosis of patients with Fabry cardiomyopathy.
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Cardiomiopatias/genética , Avaliação Pré-Clínica de Medicamentos , Doença de Fabry/genética , alfa-Galactosidase/genética , Cardiomiopatias/tratamento farmacológico , Cardiomiopatias/fisiopatologia , Doença de Fabry/tratamento farmacológico , Doença de Fabry/fisiopatologia , Feminino , Humanos , Células-Tronco Pluripotentes Induzidas/efeitos dos fármacos , Miócitos Cardíacos/efeitos dos fármacos , Pacientes , Triexosilceramidas/genética , Inativação do Cromossomo X/genéticaRESUMO
We analyzed torsadogenic and pharmacokinetic profile of E-4031 using chronic atrioventricular block dogs. E-4031 in intravenous doses of 0.03, 0.1 and 0.3 mg/kg over 10 min prolonged QT/QTc, and increased short-term variability of QT in a dose-related manner (n = 4), resulting in onset of torsade de pointes in 1 animal after the middle dose and 4 animals after the high dose, while it attained peak plasma concentrations of 16.5, 60.5 and 182.5 ng/mL at 10 min after their start of administration, respectively (n = 2). These results bridge the gap of information between in vitro proarrhythmia assay and clinical observation in human subjects.
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Antiarrítmicos/efeitos adversos , Antiarrítmicos/farmacocinética , Bloqueio Atrioventricular/fisiopatologia , Eletrocardiografia/efeitos dos fármacos , Piperidinas/efeitos adversos , Piperidinas/farmacocinética , Piridinas/efeitos adversos , Piridinas/farmacocinética , Torsades de Pointes/induzido quimicamente , Animais , Antiarrítmicos/administração & dosagem , Bloqueio Atrioventricular/complicações , Doença Crônica , Cães , Relação Dose-Resposta a Droga , Humanos , Infusões Intravenosas , Piperidinas/administração & dosagem , Piridinas/administração & dosagem , Torsades de Pointes/etiologiaRESUMO
We examined electrophysiological indices of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) sheets in order to quantitatively estimate Na+, K+ and Ca2+ channel blocking actions of bepridil and amiodarone using microelectrode array system in comparison with that of E-4031. We analyzed the field potential duration, effective refractory period, current threshold and conduction property using a programmed electrical stimulation protocol to obtain the post repolarization refractoriness and coefficient a of the relationship between the pacing cycle length and field potential duration. Electropharmacological profile of each drug was successfully characterized; namely, 1) the changes in the current threshold and conduction property provided basic information of Na+ channel blocking kinetics, 2) the relationship between pacing cycle length and field potential duration reflected drug-induced inhibition of human ether-à-go-go-related gene (hERG) K+ channel, 3) the post repolarization refractoriness indicated the relative contribution of these drugs to Na+ and K+ channel blockade, and 4) L-type Ca2+ channel blocking action was more obvious in the field potential waveform of the hiPSC-CMs sheets than that expected in the electrocardiogram in humans. Thus, this information may help to better utilize the hiPSC-CMs sheets for grasping the properties and net effects of drug-induced Na+, Ca2+ and K+ channel blockade.
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Amiodarona/farmacologia , Antiarrítmicos , Bepridil/farmacologia , Bloqueadores dos Canais de Cálcio/farmacologia , Avaliação Pré-Clínica de Medicamentos/métodos , Células-Tronco Pluripotentes Induzidas , Microeletrodos , Miócitos Cardíacos/fisiologia , Bloqueadores dos Canais de Potássio/farmacologia , Bloqueadores dos Canais de Sódio/farmacologia , Potenciais de Ação/efeitos dos fármacos , Células Cultivadas , Fenômenos Eletrofisiológicos/efeitos dos fármacos , Humanos , Piperidinas/farmacologia , Piridinas/farmacologiaRESUMO
Although azithromycin can suppress cardiac INa, IKr, IKs, ICa,L and IK1, its onset mechanisms for cardiovascular death have not been fully investigated. We examined electropharmacological effects of azithromycin in intravenous doses of 0.3, 3 and 30 mg/kg using microminipigs under the halothane anesthesia (n = 4), which provided plasma concentrations of 3.1, 11.2 and 120.4 µg/mL, respectively. The low dose did not alter any of the cardiohemodynamic or electrocardiographic variables. The middle dose significantly shortened QT interval for 10-20 min and QTc for 10-30 min. The high dose significantly decreased mean blood pressure for 5-60 min, prolonged QRS width at 20 min, but shortened QT interval for 15-20 min and QTc for 15-30 min (n = 3). Cardiohemodynamic collapse occurred in 1 animal after the start of the high dose infusion, which might be associated with the cardiovascular death in patients with vasomotor dysfunction. Prolongation of QRS width indicates that azithromycin may suppress ventricular INa in vivo, which may unmask latent type of Brugada electrocardiographic genotype. Meanwhile, abbreviation of the QTc might cause potentially lethal, short QT-related, cardiac arrhythmia syndrome. These findings with microminipigs suggest the possible entry point for analyzing the mechanisms of cardiovascular death clinically seen with this antibiotic.
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Azitromicina/toxicidade , Pressão Sanguínea/efeitos dos fármacos , Doenças Cardiovasculares/induzido quimicamente , Eletrocardiografia/efeitos dos fármacos , Animais , Azitromicina/sangue , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Masculino , Suínos , Porco MiniaturaRESUMO
Effects of moxifloxacin on QTc as well as proarrhythmic surrogate markers including J-Tpeakc, Tpeak-Tend and short-term variability (STV) of repolarization were examined by using both standard E14 time-based evaluation and exposure-response modeling. The study was conducted with a single-blind, randomized, single-dose, placebo-controlled and two-period cross-over design in healthy Filipino subjects. QT interval was corrected by Fridericia's formula (QTcF). In the E14 time-based evaluation of ECG data, the largest ΔΔQTcF with 90% confidence interval was 14.1 ms (11.2-16.9) with Cmax of 3.39 µg/mL at 3 h post-dose (n = 69; male: 35, female: 34), indicating a positive effect on the QTcF. Moxifloxacin significantly increased the ΔΔJ-Tpeakc and ΔΔTpeak-Tend, whereas the ΔΔSTV was not altered. Meanwhile in the exposure-response modeling of the same ECG data, the slope of moxifloxacin plasma concentration-ΔΔQTcF relationship was 4.84 ms per µg/mL and the predicted ΔΔQTcF with 90% confidence interval was 13.8 ms (13.1-15.1) at Cmax, also indicating a positive effect on the QTcF. Importantly, results in each proarrhythmic surrogate marker obtained by the exposure-response modeling also showed high similarity to those obtained by the E14 statistical evaluation. Thus, these results of moxifloxacin may become a guide to estimate proarrhythmic potential of new chemical entities.
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Arritmias Cardíacas/induzido quimicamente , Arritmias Cardíacas/diagnóstico , Eletrocardiografia , Fluoroquinolonas/efeitos adversos , Fluoroquinolonas/farmacologia , Adulto , Biomarcadores , Estudos Cross-Over , Eletrocardiografia/efeitos dos fármacos , Feminino , Fluoroquinolonas/farmacocinética , Voluntários Saudáveis , Humanos , Síndrome do QT Longo/induzido quimicamente , Síndrome do QT Longo/diagnóstico , Masculino , Pessoa de Meia-Idade , Moxifloxacina , Filipinas , Caracteres Sexuais , Método Simples-Cego , Adulto JovemRESUMO
Microminipigs are expected as a novel animal model for cardiovascular pharmacological experiments. Since inherent vulnerability of coronary circulation of microminipigs has not been characterized, we performed dipyridamole-stress test to both microminipigs and beagle dogs, and compared the results. Dipyridamole in doses of 0.056 and 0.56 mg/kg were intravenously infused over 10 min (n = 4 for each animal). Dipyridamole decreased the systolic/diastolic blood pressures and double product in dogs as well as in microminipigs; but it did not significantly alter the heart rate or the global balance between the myocardial oxygen demand and supply in either animal. While organic coronary arterial stenosis was not detected in either animal, dogs have well-developed epicardial intracoronary networks unlike microminipigs. Like in humans, dipyridamole did not affect the ST segment of microminipigs, whereas it substantially depressed that in dogs. The results indicate the onset of subendocardial ischemia by dipyridamole in dogs may be partly associated with their well-developed native coronary collateral channels. Microminipigs would be more useful to evaluate the drugs which may affect the coronary circulation in the pre-clinical study than dogs.
Assuntos
Anestesia , Circulação Coronária/efeitos dos fármacos , Dipiridamol/farmacologia , Cães , Eletrocardiografia/efeitos dos fármacos , Hemodinâmica/efeitos dos fármacos , Modelos Animais , Porco Miniatura , Animais , Circulação Colateral/efeitos dos fármacos , Dipiridamol/administração & dosagem , Relação Dose-Resposta a Droga , Feminino , Infusões Intravenosas , Masculino , SuínosRESUMO
A beverage made of red wine vinegar and grape juice (Yamanashi-no-megumi™) was developed as a supplemental fluid containing polyphenols, which has been clinically shown to enhance the colonic transit. In this study, we assessed the mechanism of its prokinetic action by analyzing the effects on both the colonic phosphodiesterase activity of rats (n=4) and the isolated colonic strip preparation of guinea pigs (n=4). The 7% (v/v) solution of the beverage significantly decreased the phosphodiesterase activity by 9% (n=4). The beverage in concentrations of 0.7, 2.1 and 7% (v/v) relaxed the colonic strips pre-contracted by 1 µmol/L of carbachol in a concentration-related manner with 50, 58 and 79%, each response of which was diminished to 11, 19 and 46%, respectively in the presence of 100 µmol/L of L-nitro-arginine methyl ester. These results obtained by biochemical, functional and pharmacological analyses suggest that the beverage could relax the colon through both cAMP-associated and nitric oxide-dependent pathways, which may partly explain clinically observed prokinetic effect of the beverage.
Assuntos
Ácido Acético/química , Bebidas , Colo/fisiologia , Músculo Liso/fisiologia , Polifenóis/administração & dosagem , Vinho/análise , Ácido Acético/efeitos adversos , Animais , Bebidas/efeitos adversos , Agonistas Colinérgicos/farmacologia , Colo/efeitos dos fármacos , Colo/enzimologia , Colo/fisiopatologia , Constipação Intestinal/enzimologia , Constipação Intestinal/fisiopatologia , Constipação Intestinal/prevenção & controle , Inibidores Enzimáticos/farmacologia , Feminino , Sucos de Frutas e Vegetais/efeitos adversos , Sucos de Frutas e Vegetais/análise , Cobaias , Técnicas In Vitro , Masculino , Contração Muscular/efeitos dos fármacos , Relaxamento Muscular/efeitos dos fármacos , Músculo Liso/efeitos dos fármacos , Músculo Liso/enzimologia , Músculo Liso/fisiopatologia , Óxido Nítrico Sintase/antagonistas & inibidores , Óxido Nítrico Sintase/metabolismo , Inibidores de Fosfodiesterase/farmacologia , Diester Fosfórico Hidrolases/metabolismo , Polifenóis/efeitos adversos , Polifenóis/uso terapêutico , Ratos Sprague-Dawley , Vitis/efeitos adversos , Vitis/química , Vinho/efeitos adversosRESUMO
Hypertrophic cardiomyopathy (HCM) is a genetic disorder that is characterized by hypertrophy of the myocardium. Some of the patients are diagnosed for HCM during infancy, and the prognosis of infantile HCM is worse than general HCM. Nevertheless, pathophysiology of infantile HCM is less investigated and remains largely unknown. In the present study, we generated induced pluripotent stem cells (iPSCs) from two patients with infantile HCM: one with Noonan syndrome and the other with idiopathic HCM. We found that iPSC-derived cardiomyocytes (iPSC-CMs) from idiopathic HCM patient were significantly larger and showed higher diastolic intracellular calcium concentration compared with the iPSC-CMs from healthy subject. Unlike iPSC-CMs from the adult/adolescent HCM patient, arrhythmia was not observed as a disease-related phenotype in iPSC-CMs from idiopathic infantile HCM patient. Phenotypic screening revealed that Pyr3, a transient receptor potential channel 3 channel inhibitor, decreased both the cell size and diastolic intracellular calcium concentration in iPSC-CMs from both Noonan syndrome and idiopathic infantile HCM patients, suggesting that the target of Pyr3 may play a role in the pathogenesis of infantile HCM, regardless of the etiology. Further research may unveil the possibility of Pyr3 or its derivatives in the treatment of infantile HCM.
Assuntos
Cardiomiopatia Hipertrófica/metabolismo , Células-Tronco Pluripotentes Induzidas/metabolismo , Programas de Rastreamento/métodos , Síndrome de Noonan/metabolismo , Canais de Potencial de Receptor Transitório/antagonistas & inibidores , Adulto , Cálcio/metabolismo , Cardiomiopatia Hipertrófica/diagnóstico , Cardiomiopatia Hipertrófica/tratamento farmacológico , Cardiomiopatia Hipertrófica/patologia , Pré-Escolar , Humanos , Masculino , Mutação , Miocárdio/patologia , Miócitos Cardíacos/patologia , Síndrome de Noonan/diagnóstico , Síndrome de Noonan/tratamento farmacológico , Síndrome de Noonan/patologia , Fenótipo , Prevalência , Canais de Potencial de Receptor Transitório/uso terapêuticoRESUMO
Fatal cases with the use of atypical antipsychotic drug paliperidone have been reported; however, there was no clinical report describing paliperidone-induced torsade de pointes. In this study we assessed its electropharmacological effects together with its proarrhythmic potential in intravenous doses of 0.03, 0.3 and 3 mg/kg using the halothane-anesthetized dogs (n = 5), which could provide approximately 2, 20 and 200 times higher peak plasma drug concentrations than its therapeutic level, respectively. Paliperidone exerted potent vasodilator effect resulting in hypotension, which may be largely explained by its α1-adrenoceptor blocking action. In vivo electrophysiological results suggest that paliperidone may inhibit human ether-à-go-go-related gene K+ channel in a dose-related manner and modestly suppress Na+ channel in the in situ heart. The high dose of paliperidone may have some potential to induce early afterdepolarization that can trigger lethal ventricular arrhythmias, whereas the low and middle doses lack such proarrhythmic possibility, indicating that at least 20 times higher plasma concentration may be considered to be safe.
Assuntos
Anestesia por Inalação , Anestésicos Inalatórios , Antipsicóticos/efeitos adversos , Arritmias Cardíacas/induzido quimicamente , Halotano , Palmitato de Paliperidona/efeitos adversos , Antagonistas de Receptores Adrenérgicos alfa 1 , Animais , Antipsicóticos/administração & dosagem , Antipsicóticos/sangue , Cães , Relação Dose-Resposta a Droga , Técnicas Eletrofisiológicas Cardíacas , Canais de Potássio Éter-A-Go-Go/antagonistas & inibidores , Feminino , Infusões Intravenosas , Miocárdio/metabolismo , Palmitato de Paliperidona/administração & dosagem , Palmitato de Paliperidona/sangue , Palmitato de Paliperidona/farmacologia , Bloqueadores dos Canais de Sódio , VasodilatadoresRESUMO
Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) have been used in many studies to assess proarrhythmic risks of chemical compounds. In those studies, field potential durations (FPD) of hiPSC-CMs have been corrected by clinically used Fridericia's and/or Bazett's formulae, however, the rationale for the use of these formulae has not been well established. In the present study, we developed a correction formula for experiments using hiPSC-CMs. First, we analyzed the effect of beating rate on FPD in the hiPSC-CMs sheets with electrical stimuli and a HCN channel inhibitor zatebradine. Next, we examined the relationship between the electrophysiological properties and the expression levels of ion channel genes in the cell sheets. Zatebradine slowed the beating rate and allowed to analyze FPD changes at various pacing cycle lengths. Rate-dependent change in the repolarization period was smaller in the cell sheets than that reported on the human hearts, which can be partly explained by lower gene expression level of hKCNJ2 and hKCNE1. Thus, non-linear equation for correcting FPD in the cell sheet; FPDc = FPD/RR0.22 with RR given in second was obtained, which may make it feasible to assess net repolarization delay by various chemical compounds with a chronotropic action.