Interleukin-37 has A Promising Cardioprotective Effect on Isoproterenol-Induced Myocardial Infarction / La Interleucina-37 tiene un Efecto Cardioprotector Prometedor sobre el Infarto de Miocardio Inducido por Isoproterenol

SUMMARY: The main cause of mortality and disability globally is myocardial infarction (MI). Isoproterenol (ISO), a β-adrenoceptor agonist, has been used to induce rat myocardial necrosis. Whereas interleukin-37 (IL-37) has anti-inflammatory and cytoprotective properties. The study aimed to investigate the potential protective effects of IL-37 administration on cardiac architecture, oxidative stress, and inflammatory markers during ISO-induced MI in rats. Three groups of adult male rats were used in this study, the normal control group (n=8), ISO-induced MI group (n=8) that received isoproterenol hydrochloride (ISO) (100 mg/kg/day, SC, for the first 2 consecutive days), and IL-37-treated group (ISO+IL-37) (n=8) that received recombinant human IL-37 (40 µg/kg /day, intraperitoneally, for 2 weeks during and after ISO injections. Heart rate (HR.) and ECG changes were monitored. Some oxidative stress markers such as superoxide dismutase (SOD), nitric oxide (NOx), malondialdehyde (MDA), and glutathione (GSH) tissue levels in the tissue homogenate were assayed. Interleukin- 6 (IL-6), tumor necrosis factor- α (TNF-α), caspase-8, P53, and C- reactive protein (CRP) were among the inflammatory markers examined. In addition, serum levels of creatinine kinase (CK-MB) and lactate dehydrogenase (LDH) were analyzed to evaluate the myocardial injury. For histological analysis, tissues were sectioned, fixed in paraffin, and stained with hematoxylin and eosin (H&E), Masson Trichrome and, immunohistochemical against NF-kB, TNF-α, and Caspase-9. IL-37 improved ECG changes, cardiac enzyme markers, and some inflammatory markers of oxidative stress in ISO-induced MI. It also improved the histopathological and immunohistochemical changes in MI. In conclusion: IL-37 might be a promising therapeutic modality in myocardial infarction.

La principal causa de mortalidad y discapacidad a nivel mundial es el infarto de miocardio (IM). El isoproterenol (ISO), un agonista de los receptores adrenérgicos β, se ha utilizado para inducir necrosis miocárdica en ratas. Mientras que la interleucina-37 (IL-37) tiene propiedades antiinflamatorias y citoprotectoras. El estudio tuvo como objetivo investigar los posibles efectos protectores de la administración de IL-37 en la arquitectura cardíaca, el estrés oxidativo y los marcadores inflamatorios durante el infarto de miocardio inducido por ISO en ratas. En este estudio se utilizaron tres grupos de ratas macho adultas, el grupo control normal (n=8), el grupo con IM inducido por ISO (n=8) que recibió clorhidrato de isoproterenol (ISO) (100 mg/kg/día, SC, durante los primeros 2 días consecutivos) y el grupo tratado con IL-37 (ISO+IL- 37) (n=8) que recibió IL-37 humana recombinante (40 µg/kg/día, por vía intraperitoneal, durante 2 semanas durante y después de las inyecciones de ISO. Se monitorearon la frecuencia cardíaca (FC) y los cambios en el ECG. Se analizaron algunos marcadores de estrés oxidativo como la superóxido dismutasa (SOD), el óxido nítrico (NOx), el malondialdehído (MDA) y los niveles tisulares de glutatión (GSH) en el homogeneizado de tejido. La interleucina-6 (IL-6), el factor de necrosis tumoral-α (TNF-α), la caspasa-8, la P53 y la proteína C reactiva (CRP) se encontraban entre los marcadores inflamatorios examinados. Se analizaron los niveles de creatinoquinasa (CK-MB) y lactato deshidrogenasa (LDH) para evaluar la lesión miocárdica; para el análisis histológico se seccionaron los tejidos, se fijaron en parafina y se tiñeron con hematoxilina y eosina (H&E), Tricromo de Masson e inmunohistoquímica contra NF-kB, TNF-α y Caspasa-9. IL-37 mejoró los cambios de ECG, los marcadores de enzimas cardíacas y algunos marcadores inflamatorios de estrés oxidativo en el IM inducido por ISO. Además mejoró los cambios histopatológicos e inmunohistoquímicos en MI. En conclusión: la IL-37 podría ser una modalidad terapéutica prometedora en el infarto de miocardio.

Medição automática de valva mitral a partir de ecocardiograma utilizando processamento digital de imagens / Automatic measurement of the mitral valve based on echocardiography using digital image processing

Fundamento: A avaliação da área valvar mitral por meio da reconstrução multiplano na ecocardiografia tridimensional é restrita a softwares específicos e à experiência dos ecocardiografistas. Eles precisam selecionar manualmente o frame do vídeo que contenha a área de abertura máxima da valva mitral, dimensão fundamental para a identificação de estenose mitral. Objetivo: Automatizar o processo de determinação da área de abertura máxima da valva mitral, por meio da aplicação de Processamento Digital de Imagens (PDI) em exames de ecocardiograma, desenvolvendo um algoritmo aberto com leitura de vídeo no formato avi. Método: Este estudo piloto observacional transversal foi realizado com vinte e cinco exames diferentes de ecocardiograma, sendo quinze com abertura normal e dez com estenose mitral reumática. Todos os exames foram realizados e disponibilizados por dois especialistas, com autorização do Comitê de Ética em Pesquisa, que utilizaram dois modelos de aparelhos ecocardiográficos: Vivid E95 (GE Healthcare) e Epiq 7 (Philips), com sondas multiplanares transesofágicas. Todos os vídeos em formato avi foram submetidos ao PDI através da técnica de segmentação de imagens. Resultados: As medidas obtidas manualmente por ecocardiografistas experientes e os valores calculados pelo sistema desenvolvido foram comparados utilizando o diagrama de Bland-Altman. Observou-se maior concordância entre valores no intervalo de 0,4 a 2,7 cm². Conclusão: Foi possível determinar automaticamente a área de máxima abertura das valvas mitrais, tanto para os casos advindos da GE quanto da Philips, utilizando apenas um vídeo como dado de entrada. O algoritmo demonstrou economizar tempo nas medições quando comparado com a mensuração habitual. (AU)

Background: The evaluation of mitral valve area through multiplanar reconstruction in 3-dimensional echocardiography is restricted to specific software and to the experience of echocardiographers. They need to manually select the video frame that contains the maximum mitral valve opening area, as this dimension is fundamental to identification of mitral stenosis. Objective: To automate the process of determining the maximum mitral valve opening area, through the application of digital image processing (DIP) in echocardiography tests, developing an open algorithm with video reading in avi format. Method: This cross-sectional observational pilot study was conducted with 25 different echocardiography exams, 15 with normal aperture and 10 with rheumatic mitral stenosis. With the authorization of the Research Ethics Committee, all exams were performed and made available by 2 specialists who used 2 models of echocardiographic devices: Vivid E95 (GE Healthcare) and Epiq 7 (Philips), with multiplanar transesophageal probes. All videos in avi format were submitted to DIP using the image segmentation technique. Results: The measurements obtained manually by experienced echocardiographers and the values calculated by the developed system were compared using a Bland-Altman diagram. There was greater agreement between values in the range from 0.4 to 2.7 cm². Conclusion: It was possible to automatically determine the maximum mitral valve opening area, for cases from both GE and Philips, using only 1 video as input data. The algorithm has been demonstrated to save time on measurements when compared to the usual method. (AU)

Pediatric patients head-up-tilt-test with pharmacological challenge, it is safe? / Mesa inclinada en pacientes pediátricos con reto farmacológico, ¿es seguro?

Abstract Syncope in pediatrics represents an important cause of visits to the emergency units. For this reason, excluding a cardiac or malignant origin is essential at the time of the initial approach to determine what is the next step in management, or if they need to be referred to a pediatric cardiologist and/or electrophysiologist. Vasovagal syncope is the most frequent cause of syncope in pediatrics, in which a detailed clinical history is enough to make the diagnosis. If no diagnosis is concluded by the history, or if it is necessary to define the hemodynamic response of the patients, the head-up-tilt-test is indicated; this will trigger syncope due to an orthostatic stress caused by the angulated table (passive phase). If a negative response remains, it can be followed by a pharmacologic challenge to trigger the hemodynamic response, which is still controversial in pediatrics. The pharmacologic challenge increases the sensitivity with a slight reduction in test specificity. Although there is not a specific drug for the challenge in pediatric patients yet, the most commonly drugs used are nitrates and isoproterenol, the latter related to a great number of adverse effects. Sublingual administration of nitrates in the challenge has been proven to be ideal, effective, and safe in this specific age group. The aim of this article is to make a literature search to demonstrate the effectiveness and safety of the pharmacologic challenge during the head-up-tilt-test in pediatrics, emphasizing a study conducted at the National Institute of Cardiology with isosorbide dinitrate.

Resumen El síncope en edades pediátricas representa una causa importante en las visitas a unidades de urgencias, por lo que excluir un origen cardíaco o maligno es fundamental al momento del abordaje inicial para determinar la conducta a seguir o la necesidad de derivar al cardiólogo pediatra o electrofisiólogo. El síncope vasovagal (SVV) es la causa más frecuente de síncope en pediatría, para cuyo diagnóstico basta una historia clínica detallada. Cuando ésta no es suficiente para determinar el diagnóstico de síncope reflejo o es necesario definir el tipo de respuesta que lo origina, está indicada una prueba de mesa inclinada que produce un estrés ortostático por la angulación y ello desencadena un síncope (fase pasiva). En pruebas no concluyentes está indicado un reto farmacológico para precipitar la respuesta hemodinámica, pero aún es un tema de controversia en edades pediátricas. El reto farmacológico incrementa la sensibilidad de la prueba, con una ligera reducción de la especificidad. Si bien no existe todavía un medicamento específico para la población pediátrica, los más empleados son los nitratos y el isoproterenol, este último relacionado con un mayor número de efectos adversos. La administración sublingual de los nitratos utilizados ha demostrado ser ideal, efectiva y segura en los pacientes pediátricos. El objetivo del artículo es realizar una revisión de las publicaciones médicas que demuestran la efectividad y seguridad del reto farmacológico durante la prueba de mesa inclinada en pacientes pediátricos, con énfasis en un estudio conducido en el Instituto Nacional de Cardiología con dinitrato de isosorbida (DNIS).

Aliskiren attenuates cardiac dysfunction by modulation of the mTOR and apoptosis pathways

Aliskiren (ALS) is well known for its antihypertensive properties. However, the potential underlying the molecular mechanism and the anti-hypertrophic effect of ALS have not yet been fully elucidated. The aim of the present study was to investigate the role of ALS in mammalian target of rapamycin (mTOR) and apoptosis signaling using in vivo and in vitro models of cardiac hypertrophy. A rat model of cardiac hypertrophy was induced by isoproterenol treatment (5 mg·kg-1·day-1) for 4 weeks, with or without ALS treatment at 20 mg·kg-1·day-1. The expression of hypertrophic, fibrotic, and apoptotic markers was determined by RT-qPCR. The protein expression of apoptotic markers mTOR and p-mTOR was assessed by western blot analysis. The proliferation of H9C2 cells was monitored using the MTS assay. Cell apoptosis was analyzed using flow cytometry. In vivo, isoproterenol-treated rats exhibited worse cardiac function, whereas ALS treatment reversed these dysfunctions, which were associated with changes in p-mTOR, Bcl-2, Bax, and cleaved caspase-3 expression, as well as the number of apoptotic cells. In vitro, H9C2 cardiomyocyte viability was significantly inhibited and cardiac hypertrophy was induced by Ang II administration, but ALS reversed Ang II-induced H9C2 cardiomyocyte hypertrophy and death. Furthermore, Ang II triggered the activation of the mTOR and apoptosis pathways in hypertrophic cardiomyocytes that were inhibited by ALS treatment. These results indicated that ALS alleviated cardiac hypertrophy through inhibition of the mTOR and apoptosis pathways in cardiomyocytes.

Papel dos receptores ß1 e ß2 adrenérgicos sobre a diferenciação osteoblástica de células mesenquimais estromais da medula óssea de ratos espontaneamente hipertensos / Role of ß1 and ß2 adrenergic receptor on bone marrow mesenquimal stem cells osteoblastic differentiation from hypertensive rats

Introdução: O remodelamento ósseo é um processo complexo que depende do balanço entre formação e reabsorção óssea, mecanismo regulado pelas células ósseas e fatores sistêmicos, como o Sistema Nervoso Simpático (SNS). Os mediadores deste sistema são capazes de regular o metabolismo ósseo através dos receptores adrenérgicos expressos na superfície dos osteoblastos. Entretanto, o papel dos receptores ß-adrenérgicos ainda não está totalmente elucidado no processo de diferenciação osteogênica. Objetivos: avaliar o papel dos receptores ß-adrenérgicos na diferenciação osteoblástica de células tronco mesenquimais da medula óssea de ratos normotensos e espontaneamente hipertensos (SHR). Métodos: Ratos machos Wistar e SHR (10 semanas) foram utilizados para a coleta da medula óssea a partir do fêmur, as quais foram plaqueadas em garrafas de cultivo celular e depois em placas de 24 poços, onde receberam o meio osteogênico (MO: MEM, mais 50 µg/mL de ácido ascórbico, 10 mM de ß-glicerofosfato e 10-8 M de dexametasona), e o tratamento com Isoprenalina (0,01 µM), Carvedilol (1 µM), antagonista adrenérgico não seletivo, ou Nebivolol (0,1 µM), antagonista ß1-adrenérgico. O ensaio de proliferação celular (MTT) e a atividade de fosfatase alcalina (Fal) foram realizados nos dias 7, 10 e 14. A mineralização foi avaliada no dia 14 através do vermelho de Alizarina. A expressão gênica dos marcadores osteogênicos e dos receptores ß1 e ß2 adrenérgicos foi avaliada no dia 7 por RT-PCR em tempo real. A atividade proteolítica da metaloproteinase de matriz (MMP-2) foi avaliada no mesmo período utilizando zimografia. As vias da MAPK também foram avaliadas ao final de 7 dias. Resultados: A Isoprenalina reduz a fosfatase alcalina na linhagem de células Wistar nos dois primeiros períodos, e ao final de 14 dias apresenta um aumento significativo. A adição dos -bloqueadores reverte tal resposta. Em SHR a Isoprenalina proporciona aumento da atividade de fosfatase alcalina no período intermediário. O Nebivolol inibe essa resposta no mesmo período e, em 7 dias, é capaz de reverter a redução causada pelo agonista. A Isoprenalina aumentou a expressão de todos os fatores de transcrição e o bloqueio dos receptores reverteu essa condição A Isoprenalina aumenta a expressão de Opn, Ocn e BSP nas células de animais Wistar, e em SHR aumenta apenas Ocn e o tratamento com Carvedilol corrige. A atividade de MMP-2 também foi reduzida pelo Nebivolol apenas no grupo Wistar. Além disso, o Nebivolol reduziu a expressão gênica do receptor ß1-adrenérgico. O ensaio de mineralização mostrou menor deposição mineral em Wistar. O Nebivolol também mediou a redução da fosforilação das vias da MAPK neste mesmo grupo de células. Conclusão: Nossos dados sugerem que o receptor ß1-adrenérgico pode estar envolvido na diferenciação osteogênica de células de ratos Wistar mas não em células de ratos SHR(AU)

Introduction: Bone remodeling is a complex process that depends on the balance between formation and resorption bone, a process which is regulated by bone cells and systemic factors, like the Sympathetic Nervous system (SNS). The mediators of these system are able to regulate bone metabolism through adrenergic receptors on the surface os the osteoblastos. However, the role of ß-adrenergic receptors is not clear in he osteogenic differentiation process. Thus, in this study we aimed to evaluate the role of B-adrenergic receptor on osteoblastic differentiation of bone marrow mesenchymal stem cells from normotensive and Spontaneously Hypertensive Rats (SHR). Methods: 70-days-old male Wistar and SHR rats were used for bone marrow collection from femurs, which was placed in cell culture flasks and after in to 24-well plates, where they received osteogenic medium (OM: MEN, plus 50 µg/mL ascorbic acid, 10 mM ß glycerophosphate, and 10-8 M dexamethasone) and the treatment with Isoprenaline (0.01 µM), Carvedilol (1µM), non-selective adrenergic receptor antagonist, or Nebivolol (0,1 µM), ß1-adrenergic receptor antagonist. Cell proliferation (MTT assay) and alkaline phosphatase specific activity (Alp) were analyzed at day 7, 10 and 14. Mineralization was evaluated at day 14, by Alizarin Red S. Gene expression of osteogenic markers and B1 and B2-adrenergic receptor were evaluated at day 7, by real time-RT-PCR. The proteolytic activity of matrix metalloproteinase 2 (MMP-2) were evaluated at day 7 using gelatin zymography. The MAPK pathway was evaluated at the same period. Results: Isoprenaline provides increased alkaline phosphatase activity in the intermediate period. The addition of Nebivolol includes this response over this same period and, within 7 days, was able to reverse the reduced agonist reduction. Isoprenaline increased expression of all transcription factors and receptor blockade reversed this condition Isoprenaline increases expression of Opn, Ocn and BSP in Wistar animal cells, and in SHR only increases Ocn and Carvedilol-corrected treatment. MMP-2 was reduced by Nebivolol treatment just at Wistar cells. Besides that, Nebivolol reduced Adrb1 gene expression at day 7 in Wistar group. Mineralization showed that Nebivolol reduced mineral deposition in Wistar. Nebivolol reduced MAPK proteins phosphorylation. Conclusion: Our results suggest that ß1 adrenergic receptor seems to be involved in the osteogenic differentiation of cells from Wistar rats but not in SHR cells(AU)

Pharmacological modulation of b-adrenoceptors as a new cardioprotective strategy for therapy of myocardial dysfunction induced by ischemia and reperfusion

Abstract Purpose: To evaluate the cardioprotective response of the pharmacological modulation of β-adrenergic receptors (β-AR) in animal model of cardiac ischemia and reperfusion (CIR), in spontaneously hypertensive (SHR) and normotensive (NWR) rats. Methods: CIR was induced by the occlusion of left anterior descendent coronary artery (10 min) and reperfusion (75 min). The SHR was treated with β-AR antagonist atenolol (AT, 10 mg/kg, IV) 5 min before CIR, and NWR were treated with β-AR agonist isoproterenol (ISO, 0.5 mg/kg, IV) 5 min before CIR. Results: The treatment with AT increased the incidence of VA, AVB and LET in SHR, suggesting that spontaneous cardioprotection in hypertensive animals was abolished by blockade of β-AR. In contrast, the treatment with ISO significantly reduced the incidence of ventricular arrhythmia, atrioventricular blockade and lethality in NWR (30%, 20% and 20%, respectively), suggesting that the activation of β-AR stimulate cardioprotection in normotensive animals. Serum CK-MB were higher in SHR/CIR and NWR/CIR compared to respective SHAM group (not altered by treatment with AT or ISO). Conclusion: The pharmacological modulation of β-AR could be a new cardioprotective strategy for the therapy of myocardial dysfunctions induced by CIR related to cardiac surgery and cardiovascular diseases.

Fasting/Refeeding Cycles Prevent Myocardial Dysfunction and Morphology Damage in the Spontaneously Hypertensive Rats / Ciclos de Jejum/Realimentação Previnem Disfunção Miocárdica e Danos Morfológicos em Ratos Espontaneamente Hipertensos

Abstract Background: Caloric restriction is known to impair the cardiac function and morphology in hypertrophied hearts of spontaneously hypertensive rats (SHR); however, the influence of fasting/refeeding (RF) is unknown. Objective: To investigate the fasting/refeeding approach on myocardial remodeling and function. In addition, the current study was designed to bring information regarding the mechanisms underlying the participation of Ca2+ handling and b-adrenergic system. Methods: Sixty-day-old male SHR rats were submitted to food ad libitum (C), 50% food restriction (R50) or RF cycles for 90 days. Cardiac remodeling was assessed by ultrastructure analysis and isolated papillary muscle function. The level of significance considered was 5% (a = 0.05). Results: The RF rats presented lower cardiac atrophy than R50 in relation to C rats. The C rats increased weight gain, R50 maintained their initial body weight and RF rats increased and decreased weight during RF. The RF did not cause functional impairment because the isotonic and isometric parameters showed similar behavior to those of C. The isotonic and isometric cardiac parameters were significantly elevated in RF rats compared to R50 rats. In addition, the R50 rats had cardiac damage in relation to C for isotonic and isometric variables. While the R50 rats showed focal changes in many muscle fibers, the RF rats displayed mild alterations, such as loss or disorganization of myofibrils. Conclusion: Fasting/refeeding promotes cardiac beneficial effects and attenuates myocardial injury caused by caloric restriction in SHR rats, contributing to reduce the cardiovascular risk profile and morphological injuries. Furthermore, RF promotes mild improvement in Ca2+ handling and b-adrenergic system.

Resumo Fundamento: A restrição calórica compromete a função e a morfologia cardíacas em corações hipertrofiados de ratos espontaneamente hipertensos (SHR). No entanto, a influência de ciclo de jejum/Realimentação é desconhecida. Objetivo: Investigar o efeito de ciclos de jejum/realimentação sobre a remodelação e função miocárdica. Além disso, o presente estudo foi desenhado para avaliar os mecanismos subjacentes à participação do trânsito de cálcio (Ca+2) e sistema beta-adrenérgico. Métodos: Neste estudo, SHR machos de 60 dias de idade foram submetidos a alimento ad libitum (grupo C), 50% de restrição alimentar (grupo R50) ou ciclos de RF (grupo RF) por 90 dias. A remodelação cardíaca foi avaliada por meio da análise ultraestrutural e função do músculo papilar isolado. Adotou-se o nível de significância de 5% (a = 0,05). Resultados: Os ratos do grupo RF apresentaram menor atrofia cardíaca do que os do grupo R50 em relação aos do grupo C. Os ratos do grupo C aumentaram peso corporal, os ratos do grupo R50 mantiveram seu peso corporal inicial e os ratos do grupo RF aumentaram e reduziram seu peso durante o ciclo RF. O ciclo RF não causou comprometimento funcional, pois os parâmetros isotônicos e isométricos apresentaram comportamento similar aos dos ratos do grupo C. Os parâmetros cardíacos isotônicos e isométricos mostraram-se significativamente elevados nos ratos do grupo RF em comparação aos dos ratos do grupo R50. Além disso, os ratos do grupo R50 apresentaram dano cardíaco em comparação aos ratos do grupo C quanto às variáveis isotônicas e isométricas. Os ratos do grupo R50 apresentaram alterações focais em muitas fibras musculares, enquanto os ratos do grupo RF apresentaram leves alterações, como perda ou desorganização de miofibrilas. Conclusão: Ciclos de Jejum/Realimentação promovem efeitos benéficos cardíacos e atenuam o dano miocárdico causado por restrição calórica em SHR, contribuindo para reduzir o risco cardiovascular e os danos morfológicos. Além disso, o ciclo de jejum/realimentação promove leve melhora do trânsito do Ca2+ e do sistema beta-adrenérgico.

Intraoperative awareness as an example of the influence of cardiac output on anesthetic dosing: case report / Despertar intraoperatorio como ejemplo de la influencia del gasto cardíaco en la dosificación anestésica. Reporte de caso

Abstract A case of intraoperative awareness during ablation of pulmonary veins-one of the most widely used techniques in interventional cardiology-is discussed. An infusion of isoproterenol was administered following the ablation of ectopic foci. A few seconds after the infusion the patient experienced increased heart rate and intraoperative awareness manifested as an abrupt patient movement and bispectral index elevation. This has been described in similar procedures, following the administration of isoproterenol. In our opinion, the isoproterenol infusion caused the increased heart rate and subsequent abrupt rise in cardiac output. As an inversely proportional relationship between the propofol concentrations and cardiac output has been described, we believe that this rise in cardiac output could have favored the decline in the concentrations of propofol, leading to an intraoperative awareness episode.

Resumen Presentamos un caso de despertar intraoperatorio durante la ablación de venas pulmonares, una de las técnicas más empleadas por los cardiólogos intervencionistas. Tras la ablación de focos ectópicos se procede a la infusión de isoproterenol. Segundos después de la infusión se produce un aumento de la frecuencia cardíaca seguido de un despertar intraoperatorio traducido como un movimiento brusco del paciente y un aumento en el índice bi-espectral (BIS). Esto ha sido descrito en procedimientos similares tras la administración de isoproterenol. En nuestra opinión, la infusión de isoproterenol provocó un aumento de la frecuencia cardiaca y secundariamente del gasto cardíaco de forma brusca. Dado que se ha descrito una relación inversamente propocional entre las concentraciones de propofol y el gasto cardíaco, pensamos que este aumento del gasto cardíaco pudo condicionar un descenso de las concentraciones de propofol y esto causar el episodio de despertar intraoperatorio.

Sensibilidade e Especificidade da Albumina Modificada pela Isquemia em Ratos Wistar / Sensitivity and Specificity of Ischemia Modified Albumin in Wistar Rats

O infarto agudo do miocárdio (IAM) é uma situação clínica determinada por processo isquêmicoagudo, que resulta em necrose miocárdica. Os marcadores cardíacos em caso de isquemia reversível, atualmente,apresentam sensibilidade limitada.Objetivo: Verificar a sensibilidade da albumina modificada isquêmica (AMI), como marcador cardíaco. Métodos: Estudo experimental, realizado no Laboratório de Experimentação Animal da Universidade Regional Integrada (URI), Erechim, RS, no período de 2011 a 2013. Após a indução isquêmica do miocárdio em ratos da linhagem Wistar-Tecpar, com idade aproximada entre 60-90 dias, através da administração de isoproterenol hidrocloridrato, o conteúdo da AMI foi avaliado em diferentes tempos. Resultados: Os valores da AMI mantiveram-se diminuídos durante as três horas iniciais, após a indução isquêmica pelo isoproterenol hidrocloridrato. Conclusão: Neste estudo, a albumina modificada pela isquemia foi considerada um marcador sensível,principalmente nas três horas iniciais da isquemia...

Background: Acute myocardial infarction (AMI) is a condition determined by an acute ischemic process resulting in myocardial necrosis. Cardiac markers in reversible ischemia currently have limited sensitivity. Objective: To check the sensitivity of ischemia modified albumin (IMA) as a cardiac marker.Methods: Experimental study held at the Animal Experimentation Laboratory of Universidade Regional Integrada (URI), Erechim, RS, from 2011 to 2013. After myocardial ischemic induction in Wistar-Tecpar rats aged about 60-90 days through administration of isoproterenol hydrochloride, the IMA content was evaluated at different times. Results: The IMA values remained reduced during the three first hours after ischemic induction by isoproterenol hydrochloride.Conclusion: In this study, ischemia modified albumin was considered a sensitive marker, particularly in the first three hours of ischemia...

Effects of catecholamines on volemic replacement with saline solution and the impact on heart rate variability in rabbits subjected to hemorrhage. A study by spectral analysis

PURPOSE: To verify the effects of different catecholamines on volemic expansion and on the autonomic nervous system in rabbits that were subjected to hemorrhage. METHODS: Twenty four rabbits subjected to hemorrhage (with a 25% loss of blood volume) and were randomly divided into four experimental groups: 1) HEMO Group underwent replacement with their own blood in an equal volume; 2) SS Group underwent replacement with saline solution (SS) in a volume that corresponded to three times the removed blood volume; 3) ISP Group underwent replacement with SS and isoprenaline; 4) FNL Group underwent replacement with SS and phenylephrine. Spectral Analysis of the heart rate and heart rate variability were performed from the recorded data. Hematocrit was measured throughout the experiment. RESULTS: Replacement with SS and an α- or β-agonist did not produce differences in the intravascular retention compared to replacement with SS alone. An analysis of HRV showed that the FNL group maintained the LF/HF ratio better than ISP and SS. CONCLUSIONS: No difference in vascular retention when α- or β- agonists were added to SS during post-hemorrhagic recovery. The animals in the FNL group maintained the integrity of the autonomic response within normal physiological standards during hemorrhagic stress. .

Changes in cardiac aldosterone and its synthase in rats with chronic heart failure: an intervention study of long-term treatment with recombinant human brain natriuretic peptide

The physiological mechanisms involved in isoproterenol (ISO)-induced chronic heart failure (CHF) are not fully understood. In this study, we investigated local changes in cardiac aldosterone and its synthase in rats with ISO-induced CHF, and evaluated the effects of treatment with recombinant human brain natriuretic peptide (rhBNP). Sprague-Dawley rats were divided into 4 different groups. Fifty rats received subcutaneous ISO injections to induce CHF and the control group (n=10) received equal volumes of saline. After establishing the rat model, 9 CHF rats received no further treatment, rats in the low-dose group (n=8) received 22.5 μg/kg rhBNP and those in the high-dose group (n=8) received 45 μg/kg rhBNP daily for 1 month. Cardiac function was assessed by echocardiographic and hemodynamic analysis. Collagen volume fraction (CVF) was determined. Plasma and myocardial aldosterone concentrations were determined using radioimmunoassay. Myocardial aldosterone synthase (CYP11B2) was detected by quantitative real-time PCR. Cardiac function was significantly lower in the CHF group than in the control group (P<0.01), whereas CVF, plasma and myocardial aldosterone, and CYP11B2 transcription were significantly higher than in the control group (P<0.05). Low and high doses of rhBNP significantly improved hemodynamics (P<0.01) and cardiac function (P<0.05) and reduced CVF, plasma and myocardial aldosterone, and CYP11B2 transcription (P<0.05). There were no significant differences between the rhBNP dose groups (P>0.05). Elevated cardiac aldosterone and upregulation of aldosterone synthase expression were detected in rats with ISO-induced CHF. Administration of rhBNP improved hemodynamics and ventricular remodeling and reduced myocardial fibrosis, possibly by downregulating CYP11B2 transcription and reducing myocardial aldosterone synthesis.

Tormenta eléctrica en síndrome de Brugada tratada exitosamente con infusión de isoproterenol / Electrical storm in Brugada syndrome successfully treated with isoproterenol. Report of a case

We report a 22-year-old male who experienced several episodes of syncope within a timeframe of few hours. In the emergency room, multiple ventricular fibrillation episodes where documented along with a type 1 Brugada ECG pattern. Isoproterenol in continuous infusion was started, normalizing the ECG and avoiding further arrhythmia recurrences. The patient was implanted with an automated defibrillator and discharged 3 days after admission.

Interação entre as vias de sinalização de receptores serotoninérgicos e Β-adrenérgicos em artéria femoral de ratos / Interaction between serotoninergic-and β-adrenergic receptors signaling pathways in rat femoral artery / Interacción entre las vías de señalización de receptores serotoninérgicos y β-adrenégicos en la arteria femoral de ratones

FUNDAMENTO: A doença coronária tem sido amplamente estudada em pesquisas cardiovasculares. No entanto, pacientes com doença arterial periférica (DAP) têm piores resultados em comparação àqueles com doença arterial coronariana. Portanto, os estudos farmacológicos com artéria femoral são altamente relevantes para a melhor compreensão das respostas clínicas e fisiopatológicas da DAP. OBJETIVO: Avaliar as propriedades farmacológicas dos agentes contráteis e relaxantes na artéria femoral de ratos. MÉTODOS: As curvas de resposta de concentração à fenilefrina contrátil (FC) e à serotonina (5-HT) e os agentes relaxantes isoproterenol (ISO) e forskolina foram obtidos na artéria femoral de ratos isolada. Para as respostas ao relaxamento, os tecidos foram contraídos com FC ou 5-HT. RESULTADOS: A potência de classificação na artéria femoral foi de 5-HT > FC para as respostas contráteis. Em tecidos contraídos com 5-HT, as respostas de relaxamento ao isoproterenol foram praticamente abolidas em comparação aos tecidos contraídos com FC. A forskolina, um estimulante da adenilil ciclase, restaurou parcialmente a resposta de relaxamento ao ISO em tecidos contraídos com 5-HT. CONCLUSÃO: Ocorre uma interação entre as vias de sinalização dos receptores β-adrenérgicos e serotoninérgicos na artéria femoral. Além disso, esta pesquisa fornece um novo modelo para estudar as vias de sinalização serotoninérgicas em condições normais e patológicas que podem ajudar a compreender os resultados clínicos na DAP.

BACKGROUND: Coronary heart disease has been widely studied in cardiovascular research. However, patients with peripheral artery disease (PAD) have worst outcomes compared to those with coronary artery disease. Therefore, pharmacological studies using femoral artery are highly relevant for a better understanding of the pathophysiologic responses of the PAD. OBJECTIVE: The aim of this study was to evaluate the pharmacologic properties of the contractile and relaxing agents in rat femoral artery. METHODS: Concentration response curves to the contractile phenylephrine (PE) and serotonin (5-HT) and the relaxing agents isoproterenol (ISO) and forskolin were obtained in isolated rat femoral artery. For relaxing responses, tissues were precontracted with PE or 5-HT. RESULTS: The order rank potency in femoral artery was 5-HT > PE for contractile responses. In tissues precontracted with 5-HT, relaxing responses to isoproterenol was virtually abolished as compared to PE-contracted tissues. Forskolin, a stimulant of adenylyl cyclase, partially restored the relaxing response to ISO in 5-HT-precontracted tissues. CONCLUSION: An interaction between β-adrenergic- and serotoninergic- receptors signaling pathway occurs in femoral artery. Moreover, this study provides a new model to study serotoninergic signaling pathway under normal and pathological conditions which can help understanding clinical outcomes in the PAD.

FUNDAMENTO: La enfermedad coronaria ha sido ampliamente estudiada en las investigaciones cardiovasculares. Sin embargo, los pacientes con enfermedad arterial periférica (EAP), tienen los peores resultados en comparación con aquellos con la enfermedad arterial coronaria. Por tanto, los estudios farmacológicos con la arteria femoral son extremadamente importantes para obtener una mejor comprensión de las respuestas clínicas y fisiopatológicas de la EAP. OBJETIVO: Evaluar las propiedades farmacológicas de los agentes contráctiles y relajantes en la arteria femoral de los ratones. MÉTODOS: Las curvas de concentración-respuesta a los agentes conctráctiles fenilefrina (FE) y a la serotonina (5-HT) y los agentes relajantes isoproterenol (ISO) y forskolina, se obtuvieron en la arteria femoral de ratones ya aislada. Para las respuestas a la relajación, los tejidos fueron contraídos con FE o 5-HT. RESULTADOS: La potencia de clasificación en la arteria femoral fue de 5-HT > FE para las respuestas contráctiles. En los tejidos contraídos con 5-HT, las respuestas de relajación al isoproterenol fueron prácticamente eliminadas en comparación con los tejidos contraídos con FE. La forskolina, un estimulante de la adenilil ciclasa, restauró parcialmente la respuesta de relajación al ISO en los tejidos contraídos con 5-HT. CONCLUSIÓN: Ocurre una interacción entre las vías de señalización de los receptores β-adrenérgicos y serotoninérgicos en la arteria femoral. Además, esa investigación suministra un nuevo modelo para estudiar las vías de señalización serotoninérgicas en condiciones normales y patológicas que puedan ayudar a comprender los resultados clínicos en la EAP.

Modelo experimental de infarto do miocárdio induzido por isoproterenol em ratos / Experimental model of myocardial infarction induced by isoproterenol in rats

OBJETIVO: Avaliar e validar, em nosso meio, o modelo de infarto do miocárdio induzido por isoproterenol em ratos por meio de análises de parâmetros hematológicos, bioquímicos, de marcadores do estresse oxidativo e histopatológicos. MÉTODOS: Trinta ratos jovens, machos, da linhagem Wistar (145 a 230 g), foram alocados aleatoriamente em dois grupos: grupo Simulado, submetido à falsa indução de infarto do miocárdio, e grupo Infarto, submetido à indução do infarto do miocárdio com isoproterenol. As aplicações, para indução do infarto, foram realizadas durante dois dias consecutivos, com intervalo de 24 horas entre elas. Após 24 horas da última aplicação, os ratos de ambos os grupos foram anestesiados e sacrificados para realização de coleta de sangue para hemograma e análise bioquímica (TGO, TGP, troponina I, ureia e creatinina) e coleta de fragmento do miocárdio para avaliação de marcadores do estresse oxidativo (atividade da catalase e concentração de glutationa) e exame histopatológico. RESULTADOS: Não houve mortalidade no grupo Simulado, enquanto a mortalidade no grupo Infarto foi de 25%. A indução do infarto do miocárdio com isoproterenol causou elevação das contagens de leucócitos e neutrófilos, dos níveis de TGO, troponina I e ureia, reduziu a atividade da catalase e os níveis teciduais de glutationa e causou alterações histopatológicas. Não acarretou alterações nas concentrações de hemoglobina, TGP e creatinina. CONCLUSÕES: O modelo de infarto do miocárdio induzido por isoproterenol em ratos foi adequadamente reproduzido em nosso laboratório, acarretando alterações em parâmetros hematológicos, bioquímicos, de marcadores de estresse oxidativo e histopatológicos.

OBJECTIVE: To evaluate and validate, in our laboratory, the essay of myocardial infarction induced by isoproterenol in rats by means of analysis of hematological, biochemical, oxidative stress markers and histopathological parameters. METHODS: Thirty young, male, Wistar rats (145 to 230 g) were randomly allocated in two groups: Sham group, which underwent a virtual myocardial infarction induction, and the Infarction group, which underwent a myocardial infarction induction with isoproterenol. The administrations for the infarction induction were performed during two consecutive days and a 24-hour interval between them. Twenty-four hours after the last administration, rats from both groups were anesthetized and sacrificed for blood sample collection to evaluate complete blood count (CBC) and biochemical parameters (SGOT, SGPT, troponin I, urea and creatinin), obtain myocardial fragments for oxidative stress markers analyses (catalase activity and glutathione concentrations) as well as histopathological examinations. RESULTS: There were no death cases in the Sham group, while the mortality rate in the Infarction group was 25%. Myocardial infarction induction with isoproterenol raised leukocytes and neutrophils counts, SGOT, troponin I and urea concentrations, reduced catalase enzyme activity and glutathione concentrations in the myocardium and let to histopathological concentrations as well. It did not exert alterations in terms of hemoglobin, SGPT and creatinin concentrations. CONCLUSIONS: The isoproterenol-induced myocardial infarction essay in rats was adequately reproduced in our laboratory, causing alterations in hematological, biochemical, oxidative stress markers and histopathological parameters.

Morphological alterations in salivary glands of mice (Mus musculus) submitted to tannin enriched diets: comparison with sialotrophic effects of sympathetic agonists stimulation / Alterações morfológicas das glândulas salivares de camundongos (Mus musculus) submetidos a dietas enriquecidas com taninos: comparação com os efeitos sialotróficos da estimulação com agonistas do sistema nervoso simpático

In order to study the effects of tannins at histomorphological level, mice were either fed with three structurally different types of tannins (tannic acid, chestnut, and quebracho) or treated with isoproterenol, during 10 days. Acini of parotid and submandibular glands increased significantly, being the increase higher for parotid compared to submandibular glands, and higher in the quebracho compared with the other tannin groups. Sublingual acinar size also increased after tannin consumption, by opposition to isoproterenol-treated animals. The results present evidences that the effects produced by tannins are dependent on their structure.

Estudaram-se as alterações morfológicas das glândulas salivares, induzidas por taninos, em camundongos. Os animais foram distribuídos em grupos e tratados com três diferentes tipos estruturais de taninos (ácido tânico, chestnut e quebracho - adicionados à ração) ou isoproterenol via intraperitoneal, durante 10 dias. Os ácinos das glândulas parótida e submandibulares aumentaram significativamente de tamanho, sendo o incremento maior para a parótida que para as submandibulares, e maior com o quebracho comparado com o provocado pelos outros taninos. Os ácinos das glândulas sublinguais também aumentaram após o consumo de taninos em relação aos ácinos dos animais tratados com isoproterenol. Os resultados apresentam evidências de que os efeitos produzidos pelos taninos dependem de sua estrutura.

La vía de señalización Rho a/ Rho kinasa se encuentra activada en el miocardio en ratas con fibrosis cardíaca inducida por isoprotenerol / Rho A/ Rho kinase pathway is activated in the myocardium of rats with isoprotenerol - induced fibrosis

Antecedentes: En pacientes con insuficiencia cardíaca la actividad adrenérgica está aumentada, lo que induce en el largo plazo, a cardiotoxicidad y mayor deterioro de la función ventricular. La administración experimental de Isoprotenerol, un agonista beta-adrenérgico, produce hipertrofia ventricular, daño y fibrosis miocárdica. La vía de señalización intracelular RhoA/Rho-Kinasa (ROCK) participa en el remodelamiento cardiovascular, no estando clara la relación entre la activación de esta vía y el desarrollo de fibrosis miocárdica. Objetivo: Determinar si existe activación de la vía ROCK en ratas con fibrosis miocárdica inducida experimentalmente por Isoprotenerol, mediante cuantificación de la fosforilación de la proteína blanco 1 de la fosfatasa de la miosina (MYPT1). Métodos: Se utilizaron ratas Sprague-Dawley machos (100 +/- 10 gr.); 10 como grupo control con administración de suero fisiológico y 10 en el grupo experimental con inyección subcutánea de Isoprotenerol Hemisulfato, 5 mg/kilo de peso por día, por un período de 10 días. Se determinó la presión arterial sistólica (PAS), la masa relativa ventricular izquierda (MRVI), la activación de ROCK a través de niveles de MYPT1 por Western Blot y se cuantificó la fibrosis en Ventrículo Izquierdo por análisis morfométrico del colágeno (en tinciones con Rojo de Picrosirio). Resultados (promedio +/- ES, =p<0,05): Los resultados en Presión Arterial Sistólica fueron 119,6 +/- 8,1 mmHg en el grupo control y 113,8 +/- 5,2 mmHg en el grupo tratado con Isoprotenerol, la MRVI fue de 358,3 +/- 10,9 mg/g en las controles y 495,3 +/- 42,02 mg/g en ratas Iso. La fracción volumétrica de colágeno (FVC) en miocardio y subendocardio fueron 3 +/- 0,3 y 3,3 +/- 0,4 en ratas control; en ratas Iso fueron 5,2 +/- 0,7 y 7,4 +/- 1,3 respectivamente.

Background: Patients with heart failure have increased adrenergic activity, which in turn induces cardiotoxicity, and further damage to the myocardium. lsoprotenerol induces ventricular hypertrophy with myocardial fibrosis. RHO A/ RHO Kinase pathway (ROCK) participates in myocardial remodeling, but it is not known whether ROCK is involved in the fibrotic process.Aim: To ascertain whether ROCK is activated in rats with Isoprotenerol -induced myocardial fibrosis, measuring ROCK by phosphon/ation of the myosin phosphatase (MYPTI). Methods: We used male Sprague-Dawley rats (100 +/- 10 g); 10 rats were used as controls and received sq saline,- 10 rats in the experimental group received sq Isoprotenerol (ISO rats) 5 mg/k body weight/day, during 10 days. We measured systolic blood pressure (SBP), left ventricular mass (LVM) and ROCK, which was measured by phophorylation of the MYPTI protein using Western Blot. Myocardial fibrosis was measured by morphometry of collagen in Picrosirius red stained samples, and was expressed as collagen volume fraction (CVF). Results were expressed as average +/- SEM; =p<005Results: SBP was 119,6 +/- 8,1 mmHg in controls and 113,8 +/- 5,2 mmHg in ISO rats; LVM was 358,3 +/- 10,9 mg/g in controls and 495,3 +/- 42,02 mg/g in ISO rats. CVF in the myocardium and subendocardium were 3 +/- 0,3 and 3,3 +/- 0,4 in control rats; values in ISO rats were 2 +/- 0,7 y 7,4 +/- 1,3 respectively. Total CVF were 3,2 +/- 0,4 in controls and 6,3 +/- 1,6 in ISO rats. ROCK, expressed as phosphorylated MYPTI /total MYPTI in control rats was 2,5 +/- 0,8 and 4,7 +/- 2,2 in ISO rats. Conclusion: ROCK pathway is significantly activated in the myocardium of ISO rats. ROCK antagonists for preventing myocardial fibrosis should be evaluated in this experimental model.

Ondas ultra-sônicas de alta freqüência causam disfunção endotelial em artérias coronárias caninas epicárdicas / High-frequency ultrasonic waves cause endothelial dysfunction on canine epicardial coronary arteries

OBJETIVO: Aplicação de energia por ultra-som pode facilitar a remoção da placa ateromatosa, mas o efeito desse procedimento em vasos próximos ainda é matéria de estudos experimentais. MÉTODOS: Para determinar se a energia ultra-sônica compromete a produção de óxido nítrico, segmentos de artérias coronárias caninas foram expostos a baixos (0-10 W) e altos (25 W) níveis de energia por 15 segundos, utilizando-se protótipo de aparelho para a realização de endarterectomia. Após exposição, segmentos das artérias coronarianas foram estudados em organ chambers. Para os ensaios farmacológicos foram utilizadas as seguintes drogas:difosfato de adenosina (ADP), acetilcolina (Ach) e fluoreto de sódio (NaF) para a avaliação do relaxamento dependente do endotélio. O nitroprussiato de sódio (NPS) e o isoproterenol foram utilizados para a avaliação do relaxamento independente do endotélio. RESULTADOS: A aplicação de alta energia ultra-sônica comprometeu o relaxamento dependente do endotélio induzido por ADP (10-9 - 10-4 M), Ach (10-9 - 10-4 M) e NaF (0,5 -9,5 mM) em artérias coronarianas epicárdicas. Entretanto, baixos valores de energia ultra-sônica não alteraram o relaxamento dependente do endotélio (nem o relaxamento máximo e nem a EC50) induzido pelos mesmos agonistas. O relaxamento da musculatura lisa vascular induzido por isoproterenol (10-9 - 10-5 M) ou NPS (10-9 - 10-6 M) não foi comprometido, tanto por baixos, quanto por altos níveis de energia ultra-sônica. CONCLUSÃO: Os experimentos demonstram que altas energias ultra-sônicas alteram a função endotelial. Entretanto, o ultra-som não altera a habilidade de relaxamento da musculatura lisa vascular de artérias caninas epicárdicas.

OBJECTIVE: Application of ultrasound energy by an endarterectomy probe can facilitate the removal of atheromatous plaque, but the effect of this procedure on surrounding vessel structure and function is still a matter of experimental investigations. METHODS: To determine whether ultrasound energy impairs the production of nitric oxide or damages vascular smooth muscle function, isolated canine epicardial coronary artery segments were exposed to either high (25 W) or low (0-10 W) ultrasonic energy outputs, for 15 seconds, using an endarterectomy device prototype. After exposure, segments of epicardial coronary artery were studied in organ chambers. The following drugs were used: adenosine diphosphate (ADP), acetylcholine (Ach) and sodium fluoride (NaF) to study endothelium-dependent relaxation and sodium nitroprusside (SNP) and isoproterenol to evaluate endothelium-independent relaxation. RESULTS: Application of high ultrasonic energy power impaired endothelium-dependent relaxation to ADP (10-9 - 10-4 M), Ach (10-9 - 10-4 M) and NaF (0.5 - 9.5 mM) in epicardial coronary arteries. However, low ultrasound energy output at the tip of the probe did not alter the endothelium-dependent relaxation (either maximal relaxation or EC50) to the same agonists. Vascular smooth muscle relaxation to isoproterenol (10-9 - 10-5 M) or SNP (10-9 - 10-6 M) was unaltered following exposure to either low or high ultrasonic energy outputs. CONCLUSION: These experiments currently prove that ultrasonic energy changes endothelial function of epicardial coronary arteries at high power. However, ultrasound does not alter the ability of vascular smooth muscle of canine epicardial coronary arteries to relax.

Lesions of the commissural subnucleus of the nucleus of the solitary tract increase isoproterenol-induced water intake

The nucleus of the solitary tract (NTS) is the primary site of the cardiovascular afferent information about arterial blood pressure and volume. The NTS projects to areas in the central nervous system involved in cardiovascular regulation and hydroelectrolyte balance, such as the anteroventral third ventricle region and the lateral parabrachial nucleus. The aim of the present study was to investigate the effects of electrolytic lesion of the commissural NTS on water and 0.3 M NaCl intake and the cardiovascular responses to subcutaneous injection of isoproterenol. Male Holtzman rats weighing 280 to 320 g were submitted to sham lesion or electrolytic lesion of the commissural NTS (N = 6-15/group). The sham-lesioned rats had the electrode placed along the same coordinates, except that no current was passed. Water intake induced by subcutaneous isoproterenol (30 µg/kg body weight) significantly increased in chronic (15 days) commissural NTS-lesioned rats (to 2.4 ± 0.2 vs sham: 1.9 ± 0.2 mL 100 g body weight-1 60 min-1). Isoproterenol did not induce any sodium intake in sham or in commissural NTS-lesioned rats. The isoproterenol-induced hypotension (sham: -27 ± 4 vs commissural NTS-lesioned rats: -22 ± 4 mmHg/20 min) and tachycardia (sham: 168 ± 10 vs commissural NTS: 144 ± 24 bpm/20 min) were not different between groups. The present results suggest that the commissural NTS is part of an inhibitory neural pathway involved in the control of water intake induced by subcutaneous isoproterenol, and that the overdrinking observed in lesioned rats is not the result of a cardiovascular imbalance in these animals.