RESUMO
PURPOSE: To determine the actions of isoespintanol (Isoesp) on post-ischemic myocardial and mitochondrial alterations. METHODS: Hearts removed from Wistar rats were perfused by 20 min. After this period, the coronary flow was interrupted by half an hour and re-established during 1 h. In the treated group, Isoesp was administered at the beginning of reperfusion. To assess the participation of ε isoform of protein kinase C (PKCε), protein kinase B (PKB/Akt), and nitric oxide synthase (NOS), hearts were treated with Isoesp plus the respective inhibitors (chelerythrine, wortmannin, and N-nitro-L-arginine methyl ester). Cell death was determined by triphenyl tetrazolium chloride staining technique. Post-ischemic recovery of contractility, oxidative stress, and content of phosphorylated forms of PKCε, Akt, and eNOS were also examined. Mitochondrial state was assessed through the measurement of calcium-mediated response, calcium retention capacity, and mitochondrial potential. RESULTS: Isoesp limited cell death, decreased post-ischemic dysfunction and oxidative stress, improved mitochondrial state, and increased the expression of PKCε, Akt, and eNOS phosphorylated. All these beneficial effects achieved by Isoesp were annulled by the inhibitors. CONCLUSION: These findings suggest that activation of Akt/eNOS and PKCε signaling pathways are involved in the development of Isoesp-induced cardiac and mitochondria tolerance to ischemia-reperfusion.
Assuntos
Cardiotônicos/farmacologia , Monoterpenos/farmacologia , Infarto do Miocárdio/tratamento farmacológico , Traumatismo por Reperfusão Miocárdica/tratamento farmacológico , Animais , Annonaceae , Coração/efeitos dos fármacos , Coração/fisiologia , Técnicas In Vitro , Masculino , Mitocôndrias Cardíacas/efeitos dos fármacos , Mitocôndrias Cardíacas/fisiologia , Monoterpenos/isolamento & purificação , Contração Miocárdica/efeitos dos fármacos , Infarto do Miocárdio/metabolismo , Infarto do Miocárdio/fisiopatologia , Traumatismo por Reperfusão Miocárdica/metabolismo , Traumatismo por Reperfusão Miocárdica/fisiopatologia , Miocárdio/metabolismo , Óxido Nítrico Sintase Tipo III , Proteína Quinase C-épsilon , Proteínas Proto-Oncogênicas c-akt , Ratos WistarRESUMO
There is current awareness about the central role of mitochondrial dysfunction in the development of cardiac dysfunction in systemic inflammatory syndromes, especially in sepsis and endotoxemia. The aim of this work was to elucidate the mechanism that governs the link between the severity of the systemic inflammatory insult and mitochondrial function, analysing the consequences on heart function, particularly in cardiac contractile state. Female Sprague-Dawley rats were subjected to low-grade endotoxemia (i.p. injection LPS 0.5 mg kg-1 body weight) and severe endotoxemia (i.p. injection LPS 8 mg kg-1 body weight) for 6 h. Blood NO, as well as cardiac TNF-α and IL-1ß mRNA, were found increased as the severity of the endotoxemia increases. Cardiac relaxation was altered only in severe endotoxemia, although contractile and lusitropic reserves were found impaired in both treatments in response to work-overload. Cardiac ultrastructure showed disorientation of myofibrillar structure in both endotoxemia degrees, but mitochondrial swelling and cristae disruption were only observed in severe endotoxemia. Mitochondrial ATP production, O2 consumption and mitochondrial inner membrane potential decreases were related to blood NO levels and mitochondrial protein nitration, leading to diminished ATP availability and impairment of contractile state. Co-treatment with the NOS inhibitor L-NAME or the administration of the NO scavenger c-PTIO leads to the observation that mitochondrial bioenergetics status depends on the degree of the inflammatory insult mainly determined by blood NO levels. Unravelling the mechanisms involved in the onset of sepsis and endotoxemia improves the interpretation of the pathology, and provides new horizons for novel therapeutic targets.
Assuntos
Endotoxemia/fisiopatologia , Insuficiência Cardíaca/fisiopatologia , Inflamação/fisiopatologia , Mitocôndrias Cardíacas/fisiologia , Contração Miocárdica/fisiologia , Animais , Endotoxemia/complicações , Metabolismo Energético , Feminino , Insuficiência Cardíaca/etiologia , Mitocôndrias Cardíacas/patologia , Ratos , Ratos Sprague-DawleyRESUMO
The progression of myocardial injury secondary to hypertension is a complex process related to a series of physiological and molecular factors including oxidative stress. This study aimed to investigate whether moderate-intensity exercise (MIE) could improve cardiac function and oxidative stress in spontaneously hypertensive rats (SHRs). Eight-week-old male SHRs and age-matched male Wistar-Kyoto rats were randomly assigned to exercise training (treadmill running at a speed of 20 m/min for 1 h continuously) or kept sedentary for 16 weeks. Cardiac function was monitored by polygraph; cardiac mitochondrial structure was observed by scanning electron microscope; tissue free radical production was measured using dihydroethidium staining. Expression levels of SIRT3 and SOD2 protein were measured by western blot, and cardiac antioxidants were assessed by assay kits. MIE improved the cardiac function of SHRs by decreasing left ventricular systolic pressure (LVSP), and first derivation of LVP (+LVdP/dtmax and -LVdP/dtmax). In addition, exercise-induced beneficial effects in SHRs were mediated by decreasing damage to myocardial mitochondrial morphology, decreasing production of reactive oxygen species, increasing glutathione level, decreasing oxidized glutathione level, increasing expression of SIRT3/SOD2, and increasing activity of superoxide dismutase. Exercise training in SHRs improved cardiac function by inhibiting hypertension-induced myocardial mitochondrial damage and attenuating oxidative stresses, offering new insights into prevention and treatment of hypertension.
Assuntos
Pressão Sanguínea/fisiologia , Cardiomiopatias/prevenção & controle , Hipertensão/fisiopatologia , Mitocôndrias Cardíacas/fisiologia , Estresse Oxidativo/fisiologia , Condicionamento Físico Animal/fisiologia , Animais , Cardiomiopatias/diagnóstico por imagem , Cardiomiopatias/fisiopatologia , Modelos Animais de Doenças , Masculino , Microscopia Eletrônica de Varredura , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos WKY , Superóxido Dismutase/fisiologiaRESUMO
Growth differentiation factor 11 (GDF11) is a novel factor with controversial effects on cardiac hypertrophy both in vivo and in vitro. Although recent evidence has corroborated that GDF11 prevents the development of cardiac hypertrophy, its molecular mechanism remains unclear. In our previous work, we showed that norepinephrine (NE), a physiological pro-hypertrophic agent, increases cytoplasmic Ca2+ levels accompanied by a loss of physical and functional communication between sarcoplasmic reticulum (SR) and mitochondria, with a subsequent reduction in the mitochondrial Ca2+ uptake and mitochondrial metabolism. In order to study the anti-hypertrophic mechanism of GDF11, our aim was to investigate whether GDF11 prevents the loss of SR-mitochondria communication triggered by NE. Our results show that: a) GDF11 prevents hypertrophy in cultured neonatal rat ventricular myocytes treated with NE. b) GDF11 attenuates the NE-induced loss of contact sites between both organelles. c) GDF11 increases oxidative mitochondrial metabolism by stimulating mitochondrial Ca2+ uptake. In conclusion, the GDF11-dependent maintenance of physical and functional communication between SR and mitochondria is critical to allow Ca2+ transfer between both organelles and energy metabolism in the cardiomyocyte and to avoid the activation of Ca2+-dependent pro-hypertrophic signaling pathways.
Assuntos
Cardiomegalia/metabolismo , Fatores de Diferenciação de Crescimento/metabolismo , Mitocôndrias Cardíacas/fisiologia , Miócitos Cardíacos/metabolismo , Retículo Sarcoplasmático/fisiologia , Animais , Animais Recém-Nascidos , Cálcio/metabolismo , Cardiomegalia/induzido quimicamente , Comunicação Celular , Metabolismo Energético , Mitocôndrias Cardíacas/metabolismo , Ratos Sprague-DawleyRESUMO
The progression of myocardial injury secondary to hypertension is a complex process related to a series of physiological and molecular factors including oxidative stress. This study aimed to investigate whether moderate-intensity exercise (MIE) could improve cardiac function and oxidative stress in spontaneously hypertensive rats (SHRs). Eight-week-old male SHRs and age-matched male Wistar-Kyoto rats were randomly assigned to exercise training (treadmill running at a speed of 20 m/min for 1 h continuously) or kept sedentary for 16 weeks. Cardiac function was monitored by polygraph; cardiac mitochondrial structure was observed by scanning electron microscope; tissue free radical production was measured using dihydroethidium staining. Expression levels of SIRT3 and SOD2 protein were measured by western blot, and cardiac antioxidants were assessed by assay kits. MIE improved the cardiac function of SHRs by decreasing left ventricular systolic pressure (LVSP), and first derivation of LVP (+LVdP/dtmax and −LVdP/dtmax). In addition, exercise-induced beneficial effects in SHRs were mediated by decreasing damage to myocardial mitochondrial morphology, decreasing production of reactive oxygen species, increasing glutathione level, decreasing oxidized glutathione level, increasing expression of SIRT3/SOD2, and increasing activity of superoxide dismutase. Exercise training in SHRs improved cardiac function by inhibiting hypertension-induced myocardial mitochondrial damage and attenuating oxidative stresses, offering new insights into prevention and treatment of hypertension.
Assuntos
Animais , Masculino , Ratos , Pressão Sanguínea/fisiologia , Estresse Oxidativo/fisiologia , Hipertensão/fisiopatologia , Mitocôndrias Cardíacas/fisiologia , Cardiomiopatias/prevenção & controle , Condicionamento Físico Animal/fisiologia , Ratos Endogâmicos SHR , Ratos Endogâmicos WKY , Superóxido Dismutase/fisiologia , Microscopia Eletrônica de Varredura , Modelos Animais de Doenças , Cardiomiopatias/fisiopatologia , Cardiomiopatias/diagnóstico por imagemRESUMO
Repetitive, calcium-mediated contractile activity renders cardiomyocytes critically dependent on a sustained energy supply and adequate calcium buffering, both of which are provided by mitochondria. Moreover, in vascular smooth muscle cells, mitochondrial metabolism modulates cell growth and proliferation, whereas cytosolic calcium levels regulate the arterial vascular tone. Physical and functional communication between mitochondria and sarco/endoplasmic reticulum and balanced mitochondrial dynamics seem to have a critical role for optimal calcium transfer to mitochondria, which is crucial in calcium homeostasis and mitochondrial metabolism in both types of muscle cells. Moreover, mitochondrial dysfunction has been associated with myocardial damage and dysregulation of vascular smooth muscle proliferation. Therefore, sarco/endoplasmic reticulum-mitochondria coupling and mitochondrial dynamics are now viewed as relevant factors in the pathogenesis of cardiac and vascular diseases, including coronary artery disease, heart failure, and pulmonary arterial hypertension. In this Review, we summarize the evidence related to the role of sarco/endoplasmic reticulum-mitochondria communication in cardiac and vascular muscle physiology, with a focus on how perturbations contribute to the pathogenesis of cardiovascular disorders.
Assuntos
Doenças Cardiovasculares , Mitocôndrias Cardíacas/fisiologia , Retículo Sarcoplasmático/fisiologia , Transdução de Sinais/fisiologia , Doenças Cardiovasculares/metabolismo , Doenças Cardiovasculares/fisiopatologia , Humanos , Músculo Liso Vascular/fisiologia , Miócitos Cardíacos/fisiologiaRESUMO
Background: Mitochondrial activity is essential for cardiac and skeletal muscle. The relationship between mitochondrial dysfunction and different cardiovascular conditions has been well described. Pharmacological treatment for heart failure involves different drugs as: angiotensin-converting enzyme inhibitors, B-adrenergic blockers, digitalis glycosides and diuretics. The clinical benefit from medication is clear, however, the role of this drugs in mitochondrial metabolisms is not well understood. Aim of the study: The objective of our study was to analyze structural and functional characteristics of cardiac and skeletal muscle mitochondria in mice treated with drugs normally used for heart failure and compare it to a control group. Methods: Twenty-five Albino Mice divided in five groups were treated with heart failure medication during 30 days (group I to IV). 30 days after treatment they were sacrificed, heart and skeletal muscle were analyzed and compared with a control group (V). Results: Enzymatic activity was slightly increased in groups treated with heart failure medication compared to control group (p>0.05). Mitochondrial morphology was significantly altered in groups treated compared to control group, in addition, mitochondrial area was significantly increased in the treated groups, in both cardiac and skeletal muscle. Conclusions: We concluded that heart failure medication could produce modifications in mitochondrial function; we believe that mitochondria maintains the enzymatic activity by increasing size and modifying morphology. Methods: Twenty-five Albino Mice divided in five groups were treated with heart failure medication during 30 days (group I to IV). 30 days after treatment they were sacrificed, heart and skeletal muscle were analyzed and compared with a control group (V). Results: Enzymatic activity was slightly increased in groups treated with heart failure medication compared to control group (p>0.05). Mitochondrial morphology was significantly altered in groups treated compared to control group, in addition, mitochondrial area was significantly increased in the treated groups, in both cardiac and skeletal muscle. Conclusions: We concluded that heart failure medication could produce modifications in mitochondrial function; we believe that mitochondria maintains the enzymatic activity by increasing size and modifying morphology. Results: Enzymatic activity was slightly increased in groups treated with heart failure medication compared to control group (p>0.05). Mitochondrial morphology was significantly altered in groups treated compared to control group, in addition, mitochondrial area was significantly increased in the treated groups, in both cardiac and skeletal muscle. Conclusions: We concluded that heart failure medication could produce modifications in mitochondrial function; we believe that mitochondria maintains the enzymatic activity by increasing size and modifying morphology. Conclusions: We concluded that heart failure medication could produce modifications in mitochondrial function; we believe that mitochondria maintains the enzymatic activity by increasing size and modifying morphology.
Introducción: la actividad mitocondrial es esencial para el músculo cardíaco y esquelético. La relación entre la disfunción mitocondrial y diferentes condiciones cardiovasculares ha sido bien descrita. El tratamiento farmacológico de la insuficiencia cardíaca implica diferentes medicamentos como: inhibidores de la enzima convertidora de la angiotensina, bloqueadores B-adrenérgicos, glucósidos digitálicos y diuréticos. Los beneficios clínicos del tratamiento son claros, sin embargo, el papel de estos fármacos en el metabolismo mitocondrial no esta bien establecido.Objetivo del estudio: El objetivo de nuestro estudio fue analizar las características estructurales y funcionales de las mitocondrias del músculo cardíaco y esquelético en ratones tratados con fármacos habitualmente utilizados para la insuficiencia cardíaca y compararlo con un grupo control.Métodos: Veinticinco ratones albinos divididos en cinco grupos fueron tratados con la medicación para insuficiencia cardíaca durante 30 días (grupo I a IV). 30 días después del tratamiento se sacrificaron, el corazón y el músculo esquelético se analizaron y se compararon con un grupo control (V).Resultados: La actividad enzimática se incrementó ligeramente en los grupos tratados con medicamentos insuficiencia cardiaca en comparación con el grupo control (p> 0,05). morfología mitocondrial se modificó significativamente en los grupos tratados en comparación con el grupo control, además, el área mitocondrial fue significativamente mayor en los grupos tratados, tanto en el músculo cardíaco y estriado.Conclusiones: Concluimos que la medicación insuficiencia cardíaca podría producir modificaciones en la función mitocondrial; creemos que las mitocondrias pueden mantener la actividad enzimática mediante el aumento de tamaño y modificación de la morfología. Objetivo: El objetivo de nuestro estudio fue analizar las características estructurales y funcionales de las mitocondrias del músculo cardíaco y esquelético en ratones tratados con fármacos habitualmente utilizados para la insuficiencia cardíaca y compararlo con un grupo control. Métodos: Veinticinco ratones albinos divididos en cinco grupos fueron tratados con la medicación para insuficiencia cardíaca durante 30 días (grupo I a IV). 30 días después del tratamiento se sacrificaron, el corazón y el músculo esquelético se analizaron y se compararon con un grupo control (V).Resultados: La actividad enzimática se incrementó ligeramente en los grupos tratados con medicamentos insuficiencia cardiaca en comparación con el grupo control (p> 0,05). morfología mitocondrial se modificó significativamente en los grupos tratados en comparación con el grupo control, además, el área mitocondrial fue significativamente mayor en los grupos tratados, tanto en el músculo cardíaco y estriado.Conclusiones: Concluimos que la medicación insuficiencia cardíaca podría producir modificaciones en la función mitocondrial; creemos que las mitocondrias pueden mantener la actividad enzimática mediante el aumento de tamaño y modificación de la morfología. Resultados: La actividad enzimática se incrementó ligeramente en los grupos tratados con medicamentos insuficiencia cardiaca en comparación con el grupo control (p> 0,05). morfología mitocondrial se modificó significativamente en los grupos tratados en comparación con el grupo control, además, el área mitocondrial fue significativamente mayor en los grupos tratados, tanto en el músculo cardíaco y estriado.Conclusiones: Concluimos que la medicación insuficiencia cardíaca podría producir modificaciones en la función mitocondrial; creemos que las mitocondrias pueden mantener la actividad enzimática mediante el aumento de tamaño y modificación de la morfología. Conclusiones: Concluimos que la medicación insuficiencia cardíaca podría producir modificaciones en la función mitocondrial; creemos que las mitocondrias pueden mantener la actividad enzimática mediante el aumento de tamaño y modificación de la morfología.
Assuntos
Anti-Hipertensivos/uso terapêutico , Cardiotônicos/farmacologia , Diuréticos/farmacologia , Insuficiência Cardíaca/tratamento farmacológico , Dinitrato de Isossorbida/farmacologia , Mitocôndrias Cardíacas/efeitos dos fármacos , Animais , Anti-Hipertensivos/farmacologia , Atenolol/farmacologia , Digoxina/farmacologia , Modelos Animais de Doenças , Eletrocardiografia , Enalapril/farmacologia , Feminino , Furosemida/farmacologia , Insuficiência Cardíaca/fisiopatologia , Masculino , Camundongos , Mitocôndrias Cardíacas/fisiologia , Mitocôndrias Cardíacas/ultraestrutura , Espironolactona/farmacologiaRESUMO
Mitochondrial biogenesis emerges as a compensatory mechanism involved in the recovery process in endotoxemia and sepsis. The aim of this work was to analyze the time course of the cardiac mitochondrial biogenesis process occurring during endotoxemia, with emphasis on the quantitative analysis of mitochondrial function. Female Sprague-Dawley rats (45 days old) were ip injected with LPS (10 mg/kg). Measurements were performed at 0-24 h after LPS administration. PGC-1α and mtTFA expression for biogenesis and p62 and LC3 expression for autophagy were analyzed by Western blot; mitochondrial DNA levels by qPCR, and mitochondrial morphology by transmission electron microscopy. Mitochondrial function was evaluated as oxygen consumption and respiratory chain complex activity. PGC-1α and mtTFA expression significantly increased in every time point analyzed, and mitochondrial mass was increased by 20% (P<0.05) at 24 h. p62 expression was significantly decreased in a time-dependent manner. LC3-II expression was significantly increased at all time points analyzed. Ultrastructurally, mitochondria displayed several abnormalities (internal vesicles, cristae disruption, and swelling) at 6 and 18 h. Structures compatible with fusion/fission processes were observed at 24 h. A significant decrease in state 3 respiration was observed in every time point analyzed (LPS 6h: 20%, P<0.05). Mitochondrial complex I activity was found decreased by 30% in LPS-treated animals at 6 and 24h. Complex II and complex IV showed decreased activity only at 24 h. The present results show that partial restoration of cardiac mitochondrial architecture is not accompanied by improvement of mitochondrial function in acute endotoxemia. The key implication of our study is that cardiac failure due to bioenergetic dysfunction will be overcome by therapeutic interventions aimed to restore cardiac mitochondrial function.
Assuntos
Mitocôndrias Cardíacas/fisiologia , Renovação Mitocondrial , Animais , Autofagia , Temperatura Corporal , Endotoxemia/imunologia , Endotoxemia/metabolismo , Feminino , Lipopolissacarídeos/farmacologia , Proteínas Associadas aos Microtúbulos/metabolismo , Miocárdio/imunologia , Miocárdio/metabolismo , Miocárdio/patologia , Consumo de Oxigênio , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo , Ratos Sprague-Dawley , Fatores de Transcrição/metabolismoRESUMO
Cardiomyocyte hypertrophy has been associated with diminished mitochondrial metabolism. Mitochondria are crucial organelles for the production of ATP, and their morphology and function are regulated by the dynamic processes of fusion and fission. The relationship between mitochondrial dynamics and cardiomyocyte hypertrophy is still poorly understood. Here, we show that treatment of cultured neonatal rat cardiomyocytes with the hypertrophic agonist norepinephrine promotes mitochondrial fission (characterized by a decrease in mitochondrial mean volume and an increase in the relative number of mitochondria per cell) and a decrease in mitochondrial function. We demonstrate that norepinephrine acts through α1-adrenergic receptors to increase cytoplasmic Ca(2+), activating calcineurin and promoting migration of the fission protein Drp1 (encoded by Dnml1) to mitochondria. Dominant-negative Drp1 (K38A) not only prevented mitochondrial fission, it also blocked hypertrophic growth of cardiomyocytes in response to norepinephrine. Remarkably, an antisense adenovirus against the fusion protein Mfn2 (AsMfn2) was sufficient to increase mitochondrial fission and stimulate a hypertrophic response without agonist treatment. Collectively, these results demonstrate the importance of mitochondrial dynamics in the development of cardiomyocyte hypertrophy and metabolic remodeling.
Assuntos
Calcineurina/metabolismo , Mitocôndrias Cardíacas/fisiologia , Dinâmica Mitocondrial , Miócitos Cardíacos/fisiologia , Agonistas alfa-Adrenérgicos/farmacologia , Animais , Cálcio/metabolismo , Sinalização do Cálcio , Cardiomegalia/metabolismo , Células Cultivadas , Dinaminas/genética , Dinaminas/metabolismo , GTP Fosfo-Hidrolases , Hipertrofia/metabolismo , Proteínas de Membrana/metabolismo , Proteínas Mitocondriais/metabolismo , Norepinefrina/farmacologia , Transporte Proteico , Ratos Sprague-Dawley , Receptores Adrenérgicos alfa 1/metabolismoRESUMO
Los principales mecanismos que intervienen en la génesis y progresión de la insuficiencia cardiaca no se encuentran aclarados totalmente. El presente estudio se llevó a cabo para analizar la participación de las mitocondrias en la insuficiencia cardíaca y el posible paralelismo que hubiere entre el músculo cardíaco y el músculo esquelético en relación a los síntomas clínicos y el daño mitocondrial. También se analizaron los factores de riesgo para enfermedad cardiovascular en los diferentes grupos de estudio, y como se vinculan con las alteraciones estructurales y funcionales de las mitocondrias; así como se estudiaron en un modelo experimental, las posibles modificaciones de las mitocondrias cardíacas y esqueléticas producidas por los distintos fármacos utilizados para el tratamiento de la insuficiencia cardíaca.Veintisiete (27) pacientes que se sometieron a cirugía cardiovascular por diferentes razones y aceptaron participar en este estudio se incluyeron.Los criterios de inclusión para el grupo de control (n = 6) fueron pacientes de ambos sexos con fracción de eyección ventricular izquierda normal (FEVI) (> 60%), sin enfermedad reumatológica, diabetes, hipertensión arterial, dislipemia, obstrucción de vasos coronarios, siendo la comunicación interauricular el diagnóstico único para la cirugía.
Abstract: The fundamental mechanisms involved in the genesis and progression of heart failure are not clearly understood. Present study was conducted to analyze the cardiac mitochondrial involvement in heart failure, the possible parallelism between cardiac and skeletal muscle and if there is a link between clinical symptoms and mitochondrial damage. The risk factors were also analyzed in the different groups under study and the possible modification upon cardiac and skeletal mitochondria produced by the different drugs used for cardiac failure treatment was also studied in an experimental model. Twenty seven patients who underwent cardiovascular surgery for different reasons and accepted to participate in this study were included.