RESUMO
BACKGROUND@#Dysfunction of the gap junction channel protein connexin 43 (Cx43) contributes to myocardial ischemia/reperfusion (I/R)-induced ventricular arrhythmias. Cx43 can be regulated by small ubiquitin-like modifier (SUMO) modification. Protein inhibitor of activated STAT Y (PIASy) is an E3 SUMO ligase for its target proteins. However, whether Cx43 is a target protein of PIASy and whether Cx43 SUMOylation plays a role in I/R-induced arrhythmias are largely unknown.@*METHODS@#Male Sprague-Dawley rats were infected with PIASy short hairpin ribonucleic acid (shRNA) using recombinant adeno-associated virus subtype 9 (rAAV9). Two weeks later, the rats were subjected to 45 min of left coronary artery occlusion followed by 2 h reperfusion. Electrocardiogram was recorded to assess arrhythmias. Rat ventricular tissues were collected for molecular biological measurements.@*RESULTS@#Following 45 min of ischemia, QRS duration and QTc intervals statistically significantly increased, but these values decreased after transfecting PIASy shRNA. PIASy downregulation ameliorated ventricular arrhythmias induced by myocardial I/R, as evidenced by the decreased incidence of ventricular tachycardia and ventricular fibrillation, and reduced arrythmia score. In addition, myocardial I/R statistically significantly induced PIASy expression and Cx43 SUMOylation, accompanied by reduced Cx43 phosphorylation and plakophilin 2 (PKP2) expression. Moreover, PIASy downregulation remarkably reduced Cx43 SUMOylation, accompanied by increased Cx43 phosphorylation and PKP2 expression after I/R.@*CONCLUSION@#PIASy downregulation inhibited Cx43 SUMOylation and increased PKP2 expression, thereby improving ventricular arrhythmias in ischemic/reperfused rats heart.
Assuntos
Ratos , Masculino , Animais , Traumatismo por Reperfusão Miocárdica/metabolismo , Conexina 43/genética , Sumoilação , Regulação para Baixo , Ratos Sprague-Dawley , Arritmias Cardíacas/tratamento farmacológico , Isquemia Miocárdica/metabolismo , RNA Interferente Pequeno/metabolismoRESUMO
OBJECTIVE@#To explore the effect of Kuanxiong Aerosol (KXA) on isoproterenol (ISO)-induced myocardial injury in rat models.@*METHODS@#Totally 24 rats were radomly divided into control, ISO, KXA low-dose and high-dose groups according to the randomized block design method, and were administered by intragastric administration for 10 consecutive days, and on the 9th and 10th days, rats were injected with ISO for 2 consecutive days to construct an acute myocardial ischemia model to evaluate the improvement of myocardial ischemia by KXA. In addition, the diastolic effect of KXA on rat thoracic aorta and its regulation of ion channels were tested by in vitro vascular tension test. The influence of KXA on the expression of calcium-CaM-dependent protein kinase II (CaMK II)/extracellular regulated protein kinases (ERK) signaling pathway has also been tested.@*RESULTS@#KXA significantly reduced the ISO-induced increase in ST-segment, interventricular septal thickness, cardiac mass index and cardiac tissue pathological changes in rats. Moreover, the relaxation of isolated thoracic arterial rings that had been precontracted using norepinephrine (NE) or potassium chloride (KCl) was increased after KXA treatment in an endothelium-independent manner, and was attenuated by preincubation with verapamil, but not with tetraethylammonium chloride, 4-aminopyridine, glibenclamide, or barium chloride. KXA pretreatment attenuated vasoconstriction induced by CaCl2 in Ca2+-free solutions containing K+ or NE. In addition, KXA pretreatment inhibited accumulation of Ca2+ in A7r5 cells mediated by KCl and NE and significantly decreased p-CaMK II and p-ERK levels.@*CONCLUSION@#KXA may inhibit influx and release of calcium and activate the CaMK II/ERK signaling pathway to produce vasodilatory effects, thereby improving myocardial injury.
Assuntos
Animais , Ratos , Aerossóis , Aorta Torácica , Cálcio/metabolismo , Endotélio Vascular/metabolismo , Isquemia Miocárdica/metabolismo , VasodilataçãoRESUMO
Reperfusion strategies in acute myocardial infarction (AMI) can cause a series of additional clinical damage, defined as myocardial ischemia/reperfusion (I/R) injury, and thus there is a need for effective therapeutic methods to attenuate I/R injury. miR-26a-5p has been proven to be an essential regulator for biological processes in different cell types. Nevertheless, the role of miR-26a-5p in myocardial I/R injury has not yet been reported. We established an I/R injury model in vitro and in vivo. In vitro, we used cardiomyocytes to simulate I/R injury using hypoxia/reoxygenation (H/R) assay. In vivo, we used C57BL/6 mice to construct I/R injury model. The infarct area was examined by TTC staining. The level of miR-26a-5p and PTEN was determined by bioinformatics methods, qRT-PCR, and western blot. In addition, the viability and apoptosis of cardiomyocytes were separately detected by MTT and flow cytometry. The targeting relationship between miR-26a-5p and PTEN was analyzed by the TargetScan website and luciferase reporter assay. I/R and H/R treatment induced myocardial tissue injury and cardiomyocyte apoptosis, respectively. The results showed that miR-26a-5p was down-regulated in myocardial I/R injury. PTEN was found to be a direct target of miR-26a-5p. Furthermore, miR-26a-5p effectively improved viability and inhibited apoptosis in cardiomyocytes upon I/R injury by inhibiting PTEN expression to activate the PI3K/AKT signaling pathway. miR-26a-5p could protect cardiomyocytes against I/R injury by regulating the PTEN/PI3K/AKT pathway, which offers a potential approach for myocardial I/R injury treatment.
Assuntos
Animais , Coelhos , Traumatismo por Reperfusão Miocárdica/metabolismo , Isquemia Miocárdica/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Miócitos Cardíacos/patologia , MicroRNAs/metabolismo , PTEN Fosfo-Hidrolase/metabolismo , Transdução de Sinais , Western Blotting , Modelos Animais de Doenças , Proteínas Proto-Oncogênicas c-akt/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Citometria de Fluxo , Camundongos Endogâmicos C57BLRESUMO
Abstract The heat shock proteins are endogenous proteins with the ability to act as molecular chaperones. Methods that provide cell protection by way of some damage can positively influence the results of surgery. The present review summarizes current knowledge concerning the cardioprotective role of the heat shock proteins as occurs in heart damage, including relevant information about the stresses that regulate the expression of these proteins and their potential role as biomarkers of heart disease.
Assuntos
Humanos , Isquemia Miocárdica/metabolismo , Miócitos Cardíacos/fisiologia , Procedimentos Cirúrgicos Cardíacos , Proteínas de Choque Térmico/fisiologia , Biomarcadores/metabolismo , Proteínas de Choque Térmico/análise , Miocárdio/metabolismo , Miocárdio/químicaRESUMO
Long non-coding RNAs (lncRNAs) play an important role in the pathogenesis of cardiovascular diseases, especially in myocardial infarction and ischemia/reperfusion (I/R). However, the underlying molecular mechanism remains unclear. In this study, we determined the role and the possible underlying molecular mechanism of lncRNA-ROR in myocardial I/R injury. H9c2 cells and human cardiomyocytes (HCM) were subjected to either hypoxia/reoxygenation (H/R), I/R or normal conditions (normoxia). The expression levels of lncRNA-ROR were detected in serum of myocardial I/R injury patients, H9c2 cells, and HCM by qRT-PCR. Then, levels of lactate dehydrogenase (LDH), malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GSH-PX) were measured by kits. Cell viability, apoptosis, apoptosis-associated factors, and p38/MAPK pathway were examined by MTT, flow cytometry, and western blot assays. Furthermore, reactive oxygen species (ROS) production was determined by H2DCF-DA and MitoSOX Red probes with flow cytometry. NADPH oxidase activity and NOX2 protein levels were measured by lucigenin chemiluminescence and western blot. Results showed that lncRNA-ROR expression was increased in I/R patients and in H/R treatment of H9c2 cells and HCM. Moreover, lncRNA-ROR significantly promoted H/R-induced myocardial injury via stimulating release of LDH, MDA, SOD, and GSH-PX. Furthermore, lncRNA-ROR decreased cell viability, increased apoptosis, and regulated expression of apoptosis-associated factors. Additionally, lncRNA-ROR increased phosphorylation of p38 and ERK1/2 expression and inhibition of p38/MAPK, and rescued lncRNA-ROR-induced cell injury in H9c2 cells and HCM. ROS production, NADPH oxidase activity, and NOX2 protein levels were promoted by lncRNA-ROR. These data suggested that lncRNA-ROR acted as a therapeutic agent for the treatment of myocardial I/R injury.
Assuntos
Humanos , Isquemia Miocárdica/metabolismo , Traumatismo por Reperfusão Miocárdica/metabolismo , RNA Longo não Codificante/metabolismo , Apoptose , Western Blotting , Sobrevivência Celular , Glutationa Peroxidase/metabolismo , Hidroliases/metabolismo , Malondialdeído/metabolismo , Isquemia Miocárdica/genética , Traumatismo por Reperfusão Miocárdica/genética , Miócitos Cardíacos , Reação em Cadeia da Polimerase em Tempo Real , RNA Longo não Codificante/genética , Transdução de Sinais , Superóxido Dismutase/metabolismo , TransfecçãoRESUMO
ABSTRACT Ischemia is responsible for many metabolic abnormalities in the heart, causing changes in organ function. One of modifications occurring in the ischemic cell is changing from aerobic to anaerobic metabolism. This change causes the predominance of the use of carbohydrates as an energy substrate instead of lipids. In this case, the glycogen is essential to the maintenance of heart energy intake, being an important reserve to resist the stress caused by hypoxia, using glycolysis and lactic acid fermentation. In order to study the glucose anaerobic pathways utilization and understand the metabolic adaptations, New Zealand white rabbits were subjected to ischemia caused by Inflow occlusion technique. The animals were monitored during surgery by pH and lactate levels. Transcription analysis of the pyruvate kinase, lactate dehydrogenase and phosphoenolpyruvate carboxykinase enzymes were performed by qRT-PCR, and glycogen quantification was determined enzymatically. Pyruvate kinase transcription increased during ischemia, followed by glycogen consumption content. The gluconeogenesis increased in control and ischemia moments, suggesting a relationship between gluconeogenesis and glycogen metabolism. This result shows the significant contribution of these substrates in the organ energy supply and demonstrates the capacity of the heart to adapt the metabolism after this injury, sustaining the homeostasis during short-term myocardial ischemia.
Assuntos
Animais , Masculino , Coelhos , Traumatismo por Reperfusão Miocárdica/metabolismo , Isquemia Miocárdica/metabolismo , Gluconeogênese/fisiologia , Glicogênio/metabolismo , Traumatismo por Reperfusão Miocárdica/fisiopatologia , Isquemia Miocárdica/fisiopatologia , Modelos Animais de DoençasRESUMO
Myocardial ischemia is a major cause of death and remains a disease with extremely deficient clinical therapies and a major problem worldwide. Cold inducible RNA-binding protein (CIRBP) is reported to be involved in multiple pathological processes, including myocardial ischemia. However, the molecular mechanisms of myocardial ischemia remain elusive. Here, we first overexpressed CIRBP by transfection of pc-CIRBP (pcDNA3.1 containing coding sequenced for CIRBP) and silenced CIRBP by transfection of small interfering RNA targeting CIRBP (siCIRBP). pcDNA3.1 and the negative control of siCIRBP (siNC) were transfected into H9C2 cells to act as controls. We then constructed a cell model of myocardial ischemia through culturing cells in serum-free medium with hypoxia in H9C2 cells. Subsequently, AlamarBlue assay, flow cytometry and western blot analysis were used, respectively, to assess cell viability, reactive oxygen species (ROS) level and apoptosis, and expression levels of IκBα, p65 and Bcl-3. We demonstrated that CIRBP overexpression promoted cell proliferation (P<0.001), inhibited cell apoptosis (P<0.05), reduced ROS level (P<0.001), down-regulated phosphorylated levels of IκBα and p65 (P<0.01 or P<0.001), and up-regulated expression of Bcl-3 (P<0.001) in H9C2 cells with myocardial ischemia. The influence of CIRBP knockdown yielded opposite results. Our study revealed that CIRBP could protect H9C2 cells against myocardial ischemia through inhibition of NF-κB pathway.
Assuntos
Animais , Ratos , Isquemia Miocárdica/metabolismo , Isquemia Miocárdica/prevenção & controle , NF-kappa B/antagonistas & inibidores , Substâncias Protetoras/farmacologia , Proteínas de Ligação a RNA/farmacologia , Apoptose/efeitos dos fármacos , Western Blotting , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular , Células Cultivadas , Citometria de Fluxo , Regulação da Expressão Gênica , NF-kappa B/metabolismo , Espécies Reativas de Oxigênio/análise , Reprodutibilidade dos Testes , Reação em Cadeia da Polimerase Via Transcriptase Reversa , RNA Interferente Pequeno , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Fatores de Tempo , Transfecção/métodosRESUMO
OBJECTIVES@#To explore the metabolic characteristics of lethal bradycardia induced by myocardial ischemia in rat's serum.@*METHODS@#A rat myocardial ischemia-bradycardia-sudden cardiac death (MI-B-SCD) model was established, which was compared with the sham-operation group. The metabolic profile of postmortem serum was analyzed by gas chromatography-mass spectrometry (GC-MS), coupled with the analysis of serum metabolic characteristics using metabolomics strategies.@*RESULTS@#The serum metabolic profiles were significantly different between the MI-B-SCD rats and the control rats. Compared to the control rats, the MI-B-SCD rats had significantly higher levels of lysine, ornithine, purine, serine, alanine, urea and lactic acid; and significantly lower levels of succinate, hexadecanoic acid, 2-ketoadipic acid, glyceraldehyde, hexendioic acid and octanedioic acid in the serum. There were some correlations among different metabolites.@*CONCLUSIONS@#There is obvious metabolic alterations in the serum of MI-B-SCD rat. Both lysine and purine have a high value in diagnosing MI-B-SCD. The results are expected to provide references for forensic and clinical applications of prevention and control of sudden cardiac death.
Assuntos
Animais , Ratos , Bradicardia/patologia , Doença da Artéria Coronariana , Morte Súbita Cardíaca , Modelos Animais de Doenças , Cromatografia Gasosa-Espectrometria de Massas/métodos , Lisina/metabolismo , Metabolômica/métodos , Isquemia Miocárdica/metabolismo , Purinas/metabolismoRESUMO
OBJECTIVES@#To observe the expression changes of hypoxia inducible factor-1α(HIF-1α) and vascular endothelial growth factor-A (VEGF-A) in rats with arrhythmias, and to explore the differences of the expression pattern in the two indicators of acute myocardial ischemia caused by arrhythmias and coronary insufficiency.@*METHODS@#The arrhythmia was induced by CaCl₂, and the expression changes of HIF-1α and VEGF-A were detected by immunohistochemistry, Western blotting and real-time PCR within 6 h after the arrhythmia in rats.@*RESULTS@#The expression of HIF-1α and VEGF-A showed diffuse in the myocardial tissue of rats died from arrhythmias. Both of them increased in the early arrhythmia, then decreased. Extensive myocardial ischemia happened at the beginning of arrhythmia occurrence and its range didn't expand with time.@*CONCLUSIONS@#The expressions of HIF-1α and VEGF-A in myocardium of the rats with arrhythmia can provide evidence for the differential diagnosis of acute myocardial ischemia caused by fatal arrhythmia and coronary insufficiency.
Assuntos
Animais , Ratos , Arritmias Cardíacas/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Isquemia Miocárdica/metabolismo , Miocárdio/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismoRESUMO
Abstract Background: Coronary artery disease is 2-3 times more common in diabetic individuals. Dietary nitrate/nitrite has beneficial effects in both diabetes and cardiovascular disease. It also has protective effects against myocardial ischemia-reperfusion (IR) injury in healthy animals. However, the effects of nitrate on myocardial IR injury in diabetic rats have not yet been investigated. Objective: We examined the effects of dietary nitrate on myocardial IR injury in streptozotocin-nicotinamide-induced diabetic rats. Method: Rats were divided into four groups (n=7 in each group): control, control+nitrate, diabetes, and diabetes+nitrate. Type 2 diabetes was induced by injection of streptozotocin and nicotinamide. Nitrate (sodium nitrate) was added to drinking water (100 mg/L) for 2 months. The hearts were perfused in a Langendorff apparatus at 2 months and assessed before (baseline) and after myocardial IR for the following parameters: left ventricular developed pressure (LVDP), minimum and maximum rates of pressure change in the left ventricle (±dP/dt), endothelial nitric oxide (NO) synthase (eNOS) and inducible NO synthase (iNOS) mRNA expression, and levels of malondialdehyde (MDA) and NO metabolites (NOx). Results: Recovery of LVDP and ±dP/dt was lower in diabetic rats versus controls, but almost normalized after nitrate intake. Diabetic rats had lower eNOS and higher iNOS expression both at baseline and after IR, and dietary nitrate restored these parameters to normal values after IR. Compared with controls, heart NOx level was lower in diabetic rats at baseline but was higher after IR. Diabetic rats had higher MDA levels both at baseline and after IR, which along with heart NOx levels decreased following nitrate intake. Conclusion: Dietary nitrate in diabetic rats provides cardioprotection against IR injury by regulating eNOS and iNOS expression and inhibiting lipid peroxidation in the heart.
Resumo Fundamentos: A doença arterial coronariana é duas a três vezes mais comum em indivíduos diabéticos. O nitrato/nitrito dietético tem efeitos benéficos tanto para o diabetes quanto para a doença cardiovascular, assim como efeitos protetores contra a lesão de isquemia-reperfusão (IR) miocárdica em animais saudáveis. Porém, os efeitos do nitrato na lesão de IR miocárdica em ratos diabéticos ainda não foram investigados. Objetivos: Foram examinados os efeitos sobre a lesão de IR miocárdica da adição de nitrato à dieta de ratos com diabetes mellitus tipo 2 induzido por estreptozotocina-nicotinamida. Métodos: Os ratos foram divididos em quatro grupos (n = 7 em cada grupo): controle, controle+nitrato, diabetes e diabetes+nitrato. O diabetes foi induzido nos animais por injeção de estreptozotocina e nicotinamida. Nitrato (nitrato de sódio) foi adicionado à água de beber (100 mg/L) por 2 meses. Os corações foram perfundidos em sistema de Langendorff aos 2 meses e avaliados antes (basal) e após IR miocárdica em relação aos seguintes parâmetros: pressão desenvolvida no ventrículo esquerdo (PDVE), taxas máximas de variação positiva e negativa da pressão ventricular esquerda (±dP/dt), expressão do RNAm da óxido nítrico (NO) sintase (NOS) endotelial (eNOS) e da NOS induzível (iNOS), além de níveis de malondialdeído (MDA) e metabólitos do óxido nítrico (NOx). Resultados: A recuperação da PDVE e ±dP/dt foi inferior nos ratos diabéticos versus controles, mas quase normalizou após ingestão de nitrato. Ratos diabéticos apresentaram expressão diminuída de eNOS e aumentada de iNOS tanto no estado basal quanto após IR, e o consumo dietético de nitrato restaurou estes valores para o estado normal após a IR. O nível de NOx cardíaco foi menor nos ratos diabéticos em comparação aos controles no momento basal, mas foi superior após a IR. Ratos diabéticos apresentaram níveis mais elevados de MDA tanto no estado basal quanto após IR que, juntamente com os níveis cardíacos de NOx, reduziram após consumo dietético do nitrato. Conclusões: O consumo dietético de nitrato por ratos diabéticos ofereceu cardioproteção contra a lesão de IR através da regulação da expressão de eNOS e iNOS e inibição da peroxidação lipídica no coração.
Assuntos
Animais , Masculino , Cardiotônicos/uso terapêutico , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Isquemia Miocárdica/prevenção & controle , Diabetes Mellitus Tipo 2/complicações , Nitratos/uso terapêutico , Peroxidação de Lipídeos/fisiologia , Traumatismo por Reperfusão Miocárdica/fisiopatologia , Traumatismo por Reperfusão Miocárdica/metabolismo , Reprodutibilidade dos Testes , Resultado do Tratamento , Isquemia Miocárdica/fisiopatologia , Isquemia Miocárdica/metabolismo , Estreptozocina , Vasos Coronários/fisiopatologia , Vasos Coronários/metabolismo , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Experimental/fisiopatologia , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 2/fisiopatologia , Diabetes Mellitus Tipo 2/metabolismo , Hemodinâmica , Malondialdeído/análiseRESUMO
SUMMARY The male hypogonadism-related bone mass loss is often under diagnosed. Peak bone mass is severely affected if the hypogonadism occurs during puberty and is left untreated. We present an interesting; almost bizarre case of a male with non-functional testes early during childhood and undiagnosed and untreated hypogonadism until his fifth decade of life. Forty six year male is referred for goitre, complaining of back pain. Phenotype suggested intersexuality: gynoid proportions, micropenis, no palpable testes into the scrotum, no facial or truncal hair. His medical history had been unremarkable until the previous year when primary hypothyroidism was diagnosed and levothyroxine replacement was initiated. Later, he was diagnosed with ischemic heart disease, with inaugural unstable angina. On admission, the testosterone was 0.2 ng/mL (normal: 1.7-7.8 ng/mL), FSH markedly increased (56 mUI/mL), with normal adrenal axis, and TSH (under thyroxine replacement). High bone turnover markers, and blood cholesterol, and impaired glucose tolerance were diagnosed. The testes were not present in the scrotum. Abdominal computed tomography suggested bilateral masses of 1.6 cm diameter within the abdominal fat that were removed but no gonadal tissue was confirmed histopathologically. Vanishing testes syndrome was confirmed. The central DXA showed lumbar bone mineral density of 0.905 g/cm2, Z-score of -2.9SD. The spine profile X-Ray revealed multiple thoracic vertebral fractures. Alendronate therapy together with vitamin D and calcium supplements and trans-dermal testosterone were started. Four decades of hypogonadism associate increased cardiac risk, as well as decreased bone mass and high fracture risk.
Assuntos
Humanos , Masculino , Pessoa de Meia-Idade , /complicações , Hipogonadismo/complicações , Isquemia Miocárdica/complicações , Osteoporose/complicações , Testículo/anormalidades , /metabolismo , Hipogonadismo , Isquemia Miocárdica/metabolismo , Osteoporose/metabolismo , Osteoporose , Fatores de Risco , Testículo/metabolismo , Testículo , Testosterona/sangue , Tireotropina/sangueRESUMO
Introducción. El factor de transcripción asociado a la microftalmia ( Microphtalmia-Associated Transcription Factor , MITF) regula la expresión de genes específicos, pero no se conoce su expresión y su función a nivel cardiaco. Objetivos. Identificar la expresión del MITF en corazón y en cardiomiocitos aislados de cobayo, describir los cambios morfológicos asociados con su disminución y evaluar los niveles relativos de su expresión en cardiomiocitos aislados en condiciones de preacondicionamiento isquémico. Materiales y métodos. El análisis de la expresión relativa de la isoforma específica de tejido cardiaco ( heart-type MITF, MITF-H), se determinó mediante reacción en cadena de la polimerasa (PCR) en tiempo real semicuantitativa, secuenciación y Western blot . La disminución del ARNm del MITF se indujo con un ARN pequeño de interferencia ( short hairpin RNA interference , shRNAi) específico. El tamaño, el diámetro y el número de fibras musculares se evaluaron por observación directa con microscopía de luz. Resultados. Se amplificó un fragmento de 281 pb de ADNc; el análisis de la secuencia confirmó la identidad del exón 1 y la isoforma H del MITF. La interferencia del ARNm del MITF se asoció con un mayor índice cardiaco (peso corazón/peso corporal: 5,46 x 10 -3 Vs. 4,6 x 10 -3 ) y un incremento del diámetro de las fibras cardiacas (50,2±16 µm Vs. 38,7±14,7 µm; p<0,05, n=150). En los cardiomiocitos aislados en condiciones de preacondicionamiento isquémico, se observó una expresión relativa del MITF-H mayor que en los miocitos en normoxia y expuestos a lesión por isquemia simulada (80 y 100 veces más, n=5, p<0,05, n=3). Conclusión. Los resultados sugieren que el MITF-H podría estar involucrado en la hipertrofia, la respuesta al estrés por isquemia y la supervivencia de cardiomiocitos de cobayo.
Introduction: The microphthalmia -associated transcription factor ( MITF ) regulates the expression of specific genes and its cardiac expression and function is not known. Objectives: To identify the expression of MITF in hearts and isolated cardiomyocytes from Guinea pigs, to describe morphological changes associated with mRNA interference of MITF and to evaluate their relative changes in expression in isolated cardiomyocytes under ischemic preconditioning. Materials and methods: The cardiac specific isoform, MITF-H, and relative expression level analysis, was determined by semi-quantitative real time PCR, sequencing and Western blotting. Reduction of mRNA-MITF-H was induced by transduction of specific-MITF-shRNAi interference. The cardiac morphological changes, diameter and number of cardiac fibers were evaluated by direct observation and light microscopy. Results: A cDNA fragment of 281 bp was amplified from heart and isolated ventricular cardiac myocytes. Sequence analysis confirmed the identity of the isoform MITF-H, exon 1. The MITF silencing was associated with an increase in cardiac index (heart weight/body weight vs . 5.46 x 10 -3 vs 4.6 x 10 -3 ) and higher diameter of cardiac fibers (50.2±16 µ m vs 38,7±14,7 µ m p<0.05, n=150). In isolated cardiac myocytes under ischemic preconditioning we observed a higher relative expression compared with that measured in myocytes exposed to normoxia and simulated ischemia (eighty and one hundred times, p <0.05, n = 5). Conclusion. The results suggest that MITF-H isoform may be involved in Guinea pig cardiac hypertrophy, response to stress by ischemia and cardiomyocytes survival.
Assuntos
Animais , Feminino , Cobaias , Cardiomiopatia Hipertrófica/metabolismo , Fator de Transcrição Associado à Microftalmia/fisiologia , Miocárdio/metabolismo , Miócitos Cardíacos/metabolismo , Sequência de Aminoácidos , Sequência de Bases , Sobrevivência Celular , Células Cultivadas , Cardiomiopatia Hipertrófica/genética , DNA Complementar/genética , Regulação da Expressão Gênica , Precondicionamento Isquêmico Miocárdico , Dados de Sequência Molecular , Fator de Transcrição Associado à Microftalmia/antagonistas & inibidores , Fator de Transcrição Associado à Microftalmia/biossíntese , Fator de Transcrição Associado à Microftalmia/genética , Isquemia Miocárdica/genética , Isquemia Miocárdica/metabolismo , Miócitos Cardíacos/patologia , Oxigênio/farmacologia , Isoformas de Proteínas/biossíntese , Isoformas de Proteínas/genética , Isoformas de Proteínas/fisiologia , Interferência de RNA , RNA Interferente Pequeno/farmacologia , Alinhamento de Sequência , Homologia de SequênciaRESUMO
Increased production of oxygen free radicals and decreased oxidant capacity occur in coronary artery diseases (CAD). This pro-oxidant shift in intracellular redox state may induce cell death by either direct cell membrane damage by lipid peroxidation or apoptosis through activation of transcription factors. These changes occur not only in cardiomyocytes, but also in cardiac sympathetic nerves, which are very sensitive to oxidative damage. Patients with heart failure encounter reduced peripheral blood flow at rest, during exercise and in response to endothelium-dependent vasodilators. Current treatments of cardiomyopathy, a degenerative condition of the myocardium frequently associated with heart failure have done little to enhance patient survival. Decreased myocardial contractility and altered regulation of peripheral circulation along with oxidative conditions are important contributors to the symptoms and prognosis of the disease process. Nitric oxide formed from L-arginine (2-amino-5 guanidinovaleric acid) metabolism in endothelial cells contributes to regulation of blood flow under these conditions. L-Arginine is the precursor of nitric oxide, an endogenous messenger molecule involved in a variety of endothelium-mediated physiological effects in the vascular system. In the present study, we investigated the effect of oral administration of L-arginine (3 g/day) on the intracellular redox status of the patients of ischemic cardiomyopathy aged 45-60 yrs. The enzymatic and non-enzymatic antioxidant parameters like superoxide dismutase, catalase, total thiols (TSH) and ascorbic acid along with pro-oxidant parameters, such as xanthine oxidase, as well as index of oxidative stress as protein carbonyl content and malondialdehyde (a marker of lipid peroxidation) were investigated in the plasma and RBC lysate. L-Arginine (3 g/day) administration was found to improve the levels of these parameters in the patients and regulate the blood flow, as evident by the improved blood pressure of the patients. Thus, it is inferred that L-arginine attenuates the oxidative stress conditions along with maintaining the blood pressure rate of patients suffering from cardiomyopathy.
Assuntos
Antioxidantes/metabolismo , Arginina/metabolismo , Ácido Ascórbico/metabolismo , Cardiomiopatias/metabolismo , Catalase/metabolismo , Doença da Artéria Coronariana/metabolismo , Feminino , Radicais Livres , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Biológicos , Isquemia Miocárdica/metabolismo , Oxidantes , Oxirredução , Estresse Oxidativo , Espécies Reativas de Oxigênio/metabolismo , Superóxido Dismutase/metabolismo , Tireotropina/metabolismo , Xantina Oxidase/metabolismoRESUMO
OBJECTIVE@#To observe the changes of hypoxia-inducible factor-1 alpha (HIF-1alpha), the expression in the early stage (within 6 h) of acute myocardial ischemia and to explore the potential forensic application.@*METHODS@#SD rats were randomly divided into one control group, one sham operation group and five myocardial ischemia groups which received ligation of the left anterior descending (LAD) coronary artery. The five experiment groups divided into 15min, 30min, 1 h, 3 h and 6h after LAD ligation. The expression of HIF-1alpha was detected by immunohistochemistry, immunofluorescence and Western blotting, respectively.@*RESULTS@#Both the control group and sham operation group showed no expression of HIF-1alpha, whereas the expression of HIF-1alpha could be weakly detected beneath the endocardium at 15 min after LAD ligation. With the increase of myocardial ischemia process, the positive staining gradually extended from endocardium to epicardium, reached the peak at 3 h, and began to decrease gradually at 6h after LAD ligation but still maintained at a relatively high level. In addition, the expression of HIF-1alpha without a time-dependent way was also detected in full thickness of the right ventricle in occurrence of ventricular arrhythmia after LAD ligation.@*CONCLUSION@#HIF-1alpha may be regarded as a sensitive marker for sudden cardiac death induced by early acute myocardial ischemia, and may also be helpful for the diagnosis of fatal arrhythmia.
Assuntos
Animais , Ratos , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Imuno-Histoquímica , Isquemia Miocárdica/metabolismo , Distribuição Aleatória , Ratos Sprague-DawleyRESUMO
OBJECTIVE: To evaluate pantoprazole effect in the functional recovery of isolated hearts of rats, submitted to ischemia and reperfusion with and without ischemic preconditioning. METHODS: In four groups of eight Wistar breed rats, the hearts were removed after anesthesia and perfused with Krebs-Henseleit solution (95% O2, 5% CO2, 37ºC). GI, GII, GIII and GIV hearts were submitted to ischemia (20 min) and reperfusion (30 min). In GII and GIV, preconditioning was performed with 5 min of ischemia and 5 min of reperfusion before 20 min of the ischemia period induction. In GIII and GIV pantoprazole 100 mg was done before a 20 min-period of ischemia induction. Heart Rate (HR), Coronary Flow (CoF), Systolic Pressure (SP), +dP/dt and -dP/dt were registered before (t0) and after reperfusion (t30). Kruskal-Wallis (P<0.05) test was used. RESULTS: There were no differences (P>0.05) between groups among HR and CoF values. Differences occurred between groups, I and II, III and IV at t30 with SP reduced for 32% mean value in GI, 65% GII, 65% GIII, and 73% GIV; The t30 + dP/dtmax were 34% in GI, 61% GII, 63% GIII and 72% GIV. The t30 -dP/dtmax were GI 28%, GII 63%, GIII 75 % and GIV 75%; (P<0.05). There were no significant differences in the SP, +dP/dtmax, and -dP/dtmax between Groups II, III and IV results. CONCLUSIONS: The administration of pantoprazole before induction of ischemia significantly protected the myocardial functional recovery with the results of SP, + dP / dtmax and dP/dtmax similar to the ischemic preconditioning against ischemia-reperfusion.
OBJETIVO: Avaliar o efeito do pantoprazol na recuperação funcional de corações isolados de ratos submetidos à isquemia e reperfusão com e sem pré-condicionamento isquêmico. MÉTODOS: Em quatro grupos de oito ratos Wistar, após anestesia os corações foram removidos e perfundidos com Krebs-Henseleit (95% O2, 5% CO2, 37ºC). Os corações de GI, GII, GIII e GIV foram submetidos a 20' de isquemia e 30'de reperfusão. Em GII e GIV realizou-se pré condicionamento com 5' de isquemia e 5' de reperfusão antes dos 20' de isquemia. Em GIII e GIV, pantoprazol 100mcg foram injetados imediatamente antes dos 20' de isquemia. Frequência cardíaca (FC), Fluxo Coronariano (FCo), Pressão Sistólica (PS), + dP/dt e -dP/dt foram registrados em (T0) e (t30). Estatística: Kruskal-Wallis (P <0,05). RESULTADOS: Não houve diferenças (P> 0,05) entre grupos nos valores de FC e de CFo. Diferenças (P <0,05) ocorreram entre GI e GII, GIII e GIV, com PS t30 reduzida para 32% GI, 65% GII, 65% GIII e 73% GIV. Em t30 + dP/dtmax 34% GI, 61% GII, 63% GIII e 72% GIV. A -dP/dtmax t30 GI 28%, GII 63%, GIII 75% e GIV 75%. Não houve diferença estatística (P< 0,05) nos valores de PS, +dP/dtmax e -dP/dtmax entre os GII, GIII e GIV. CONCLUSÕES: A administração do pantoprazol antes da indução da isquemia protegeu significativamente a recuperação funcional miocárdica com resultados de SP, +dP/ dtmax e -dP/dtmax semelhantes aos do pré-condicionamento isquêmico contra lesão de isquemia-reperfusão.
Assuntos
Animais , Ratos , Inibidores Enzimáticos/farmacologia , Precondicionamento Isquêmico Miocárdico , Isquemia Miocárdica/metabolismo , Traumatismo por Reperfusão Miocárdica/prevenção & controle , /farmacologia , Inibidores Enzimáticos/efeitos adversos , Frequência Cardíaca/efeitos dos fármacos , Precondicionamento Isquêmico Miocárdico/métodos , Modelos Animais , Contração Miocárdica/efeitos dos fármacos , Distribuição Aleatória , Ratos Wistar , Recuperação de Função Fisiológica/efeitos dos fármacos , /efeitos adversosRESUMO
Abstract Coronary artery disease is the leading cause of death in the developed world and in developing countries. Acute mortality from acute myocardial infarction (MI) has decreased in the last decades. However, the incidence of heart failure (HF) in patients with healed infarcted areas is increasing. Therefore, HF prevention is a major challenge to the health system in order to reduce healthcare costs and to provide a better quality of life. Animal models of ischemia and infarction have been essential in providing precise information regarding cardiac remodeling. Several of these changes are maladaptive, and they progressively lead to ventricular dilatation and predispose to the development of arrhythmias, HF and death. These events depend on cell death due to necrosis and apoptosis and on activation of the inflammatory response soon after MI. Systemic and local neurohumoral activation has also been associated with maladaptive cardiac remodeling, predisposing to HF. In this review, we provide a timely description of the cardiovascular alterations that occur after MI at the cellular, neurohumoral and electrical level and discuss the repercussions of these alterations on electrical, mechanical and structural dysfunction of the heart. We also identify several areas where insufficient knowledge limits the adoption of better strategies to prevent HF development in chronically infarcted individuals.
Assuntos
Humanos , Insuficiência Cardíaca/etiologia , Coração/fisiopatologia , Infarto do Miocárdio/complicações , Isquemia Miocárdica/fisiopatologia , Neurônios Adrenérgicos/fisiologia , Aldosterona/fisiologia , Angiotensinas/metabolismo , Apoptose/fisiologia , Arritmias Cardíacas/etiologia , Insuficiência Cardíaca/prevenção & controle , Mediadores da Inflamação/metabolismo , Isquemia Miocárdica/metabolismo , Miocárdio/metabolismo , Miócitos Cardíacos/fisiologia , Sistema Renina-Angiotensina/fisiologia , Sistema Nervoso Simpático/fisiologia , Fatores de TempoRESUMO
Increased production of free radicals under oxidative stress conditions plays a vital role in the impairment of endothelial function and also in the pathogenesis of ischemic heart diseases. Ischemia, followed by reperfusion, leads to the exacerbated formation of oxy- free radicals. These reactive oxygen species through a chain of reactions damage the cardiomyocytes and cause more injury to the myocardium. L-Arginine is reported to act as free radical scavenger, inhibits the activity of pro-oxidant enzymes and thus acts as an antioxidant and these roles of L-arginine are mediated by nitric oxide (NO). In the present study, the effect of oral administration of L-arginine (3 g/day for 7 days) on some antioxidant enzymes, total thiols, lipid peroxidation measured as malondialdehyde (MDA), and plasma ascorbate levels in myocardial ischemic patients was investigated. We observed an increase in the activity of superoxide dismutase (SOD), total thiols (T-SH) and plasma ascorbate levels and a decrease in the activity of xanthine oxidase (XO), MDA levels, carbonyl content and serum cholesterol in the patients on oral administration of L-arginine. The present study demonstrates that L-arginine administration may be beneficial to patients with myocardial ischemic disorders, such as acute myocardial infarction and acute angina.
Assuntos
Adulto , Idoso , Arginina/administração & dosagem , Arginina/farmacologia , Arginina/uso terapêutico , Ácido Ascórbico/metabolismo , Estudos de Casos e Controles , Colesterol/sangue , Sequestradores de Radicais Livres/administração & dosagem , Sequestradores de Radicais Livres/farmacologia , Sequestradores de Radicais Livres/uso terapêutico , Humanos , Malondialdeído/metabolismo , Pessoa de Meia-Idade , Isquemia Miocárdica/sangue , Isquemia Miocárdica/tratamento farmacológico , Isquemia Miocárdica/enzimologia , Isquemia Miocárdica/metabolismo , Oxidantes/metabolismo , Compostos de Sulfidrila/metabolismo , Superóxido Dismutase/metabolismo , Xantina Oxidase/metabolismoRESUMO
To determine the frequency of hyperuricemia, as a risk factor, in patients with ischemic heart disease in our setup. This prospective and observational study was carried out in the Departments of cardiology, medical unit III and pathology, Peoples Medical College and Hospital, Nawabshah from 15[th] January 2007 to 15[th] July 2007. Fifty patients, of any age and of either sex, diagnosed on ECG as ischemic heart disease [IHD] were selected and compared with serum uric acid [SUA] levels and age, sex, approximately body mass index [BMI] matched healthy controls. SUA was measured on 3[rd] day of admission by using enzyme uricase method on CLINIKON photometer 5010. Hyperuricemia was found in 27 out of 50 IHD patients and in 5 out of 50 controls; therefore a highly significant association was observed. Mean SUA level was 7.21 +/- 2.14 in patients with ischemic heart disease and 5.38 +/- 1.26 was found in healthy control subject. The difference between these two means was highly significant [P<0.0001]. Hyperuncemia significantly associates with IHD. It does not cause t IHD, neither is an independent risk factor but it only accelerates the process of atherosclerosis which can worsen the preexisting IHD
Assuntos
Humanos , Isquemia Miocárdica/metabolismo , Hiperuricemia/epidemiologia , Ácido Úrico , Índice de Massa Corporal , Estudos Prospectivos , Fatores de RiscoRESUMO
OBJETIVO: Verificar, em modelo experimental de coração isolado de suínos, se a associação da trimetazidina à solução cardioplégica promove melhora no desempenho do coração. MÉTODOS: O modelo experimental utilizou suínos Large-White, com coração isolado perfundido por suporte de outro animal em modo de execução de trabalho ("working heart state"). Foram divididos em três grupos (n = 6), submetidos a isquemia regional seguida de isquemia global, que recebiam um dos três tratamentos: solução St Thomas (ST), solução St Thomas acrescida de trimetazidina (TMZ) e grupo controle (Co). Durante período de reperfusão, aos 30, 60 e 90 minutos, foram medidos parâmetros hemodinâmicos de contratilidade e metabólicos, obtendo-se assim a elastância máxima (Emáx), o índice de trabalho sistólico pré-recrutável (PRSW), "dureza" do ventrículo (EDPRV), fluxo coronariano, consumo de oxigênio e dosagens de lactato e glicose. Os resultados foram analisados estatisticamente. RESULTADOS: Em relação aos parâmetros hemodinâmicos de contratilidade, não houve diferença estatística significante entre os três grupos. Houve produção crescente de lactato nos três grupos de forma uniforme quanto maior o tempo de reperfusão. O fluxo coronariano, o consumo de oxigênio e o consumo de glicose tiveram grande variação entre os diferentes tempos medidos, mas sem diferença entre os três tratamentos. O peso final do ventrículo esquerdo foi significativamente menor no grupo trimetazidina (TMZ) do que nos demais. CONCLUSÃO: A administração da trimetazidina associada como adjuvante à solução cardioplégica, sem pré-tratamento, não demonstrou benefício hemodinâmico ou metabólico em modelo experimental "working heart" de coração isolado em porcos.
OBJECTIVE: The aim of this study is to verify in an isolated working heart swine model if the acute administration of trimetazidine to cardioplegia, without pre=treatment improves heart performance. METHODS: Eighteen pairs of swines were used in this working heart model, divided into three groups (n = 6) that underwent regional and global ischemia. Each group was selected to a different treatment: St Thomas cardioplegia (ST), St Thomas enriched with trimetazidine (TMZ) and control group (Co). Data was collected during reperfusion period at 30, 60 and 90 minutes. Hemodinamic parameters such as elastance contractility index (Emax), preload recruitable stroke work relationship (PRSW) and heart "stiffness" (EDPVR) were measured. Other data included coronary flow, lactate, oxygen and glucose consumption. Results were statistically analyzed. RESULTS: All contractility data were not significantly different among three groups. Lactate became constantly higher according to time uniformly in all three groups. Coronary flow, glucose consumption and oxygen consumption presented large variations during time periods but according to treatments showed no statistical differences in all three groups. Left ventricle final weight was significantly lower in trimetazidine group compared to both other groups. CONCLUSION: Administration of trimetazidine enhanced cardioplegia, without pre-treatment, showed no hemodinamic or metabolic improvement in swine isolated working heart model.
Assuntos
Animais , Feminino , Soluções Cardioplégicas/farmacologia , Modelos Cardiovasculares , Contração Miocárdica/efeitos dos fármacos , Isquemia Miocárdica/metabolismo , Trimetazidina/farmacologia , Análise de Variância , Bicarbonatos/farmacologia , Cloreto de Cálcio/farmacologia , Hemodinâmica/efeitos dos fármacos , Ácido Láctico/metabolismo , Modelos Animais , Reperfusão Miocárdica , Magnésio/farmacologia , Contração Miocárdica/fisiologia , Consumo de Oxigênio/efeitos dos fármacos , Consumo de Oxigênio/fisiologia , Perfusão/métodos , Cloreto de Potássio/farmacologia , Suínos , Cloreto de Sódio/farmacologia , Fatores de TempoRESUMO
Disturbed lipid profile is one of the most important and potent risk factors in ischemic heart disease (IHD). In recent years, it has been demonstrated that raised oxidative stress promotes several undesirable pathways including the formation of oxidised LDL (O-LDL) and oxidized cholesterol which encourages cholesterol accumulation in arterial tissues. We, therefore, aimed to ascertain the redox balance by measuring oxidative stress (OS) and total antioxidant activity (TAA) along with lipid profile to determine their possible association with IHD. Our study group comprised of 28 confirmed cases of IHD. The inclusion criterion was history of chest pain, ischemic changes in the ECG and good left ventricular (LV) function. Patients with diabetes mellitus, poor LV function, previous infarct and valvular heart disease were excluded. Lipid profile, plasma thiobarbituric acid reactive substances (TBARS), plasma total antioxidant activity (TAA) and urinary TBARS were estimated in these patients by standard procedures and the values were compared with 30 age, sex and socioeconomically matched normal healthy control subjects. Body mass index (BMI) and waist/hip ratio (W/H ratio) was also noted in both the groups. Lipid profile and OS (TBARS levels) were significantly raised in IHD patients. Though statistically not significant but TAA tended to be lower and urinary TBARS levels tended to be higher in patients. BMI, W/H ratio, smoking and alcohol did not show discernible association with lipid profile, OS or TAA. OS is significantly raised in majority of IHD patients. The non association of BMI, W/H ratio, smoking and alcohol with lipid profile, OS and TAA suggest that there are other risk factors which primarily contribute to the initiation and progression of IHD.