Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

Sub-endocardial fibres line the inner surface of both ventricles and are responsible for longitudinal oscillations of the mitral annulus, such oscillations may be measured using tissue Doppler echocardiography (IDE). During systole the annulus descends and during early diastole (ETDE) and atrial systole (ATDE) itascends. This thesis examined whether changes in the velocity of the annulus ineach of these phases of oscillation, measured using tissue Dopplerechocardiography (TDE), could determine the nature of increases in left ventricular size (pathological or physiological). Study one examined differences at rest in longitudinal velocities between individuals with hypertrophic cardiomyopathy (HCM), hypertension (HT), weightlifters, runners and controls, (n = 15 all groups) and all groups were aged between 20 - 36 years. The results demonstrated that both pathological groups had systolic and ETDE velocities significantly lower than groups with physiological hypertrophy (weightlifters or runners) or controls p < 0.05. AIDE however was not significantly different between groups. Additionally runners also demonstrated a significantly higher ETDE than either weightlifters or controls (p < 0.05). Binomial logistic regression identified longitudinal systolic velocity < 9 cm s" 1 and ETDE velocity < 11 cm s" 1 as the best combination of variables to predict pathological increases in heart size. Study two examined older subjects in order to determine whether the criteria set out in study one were applicable to senior athletes. The subject groups were the same as in study one however all subjects were aged between 36-55. In this case systolic annular velocity was significantly lower in groups with pathological LVH but ETDE < 9 cm s" 1 was a better differentiator. Binomial logistic regression identified ETDE < 9 cm s" 1 and a mitral E / A ratio < 1 as the best combination of variables to predict pathological LVH. Study three examined the age related changes in long axis function using the pooled data from studies one and two. This demonstrated that in the pathological LVH groups only ETDE / ATDE ratio was significantly correlated with age (r = - 0.5 p < 0.05) suggesting that there appears to be no summation of the effects of pathology and age on mitral annular velocities. The control groups demonstrated a significant age related reduction in all long axis variables (systolic velocity r = - 0.7 p < 0.05; ETDE r = - 0.6 p < 0.01; ATDE r = 0.5 p < 0.05; ETD E / ATDE r = - 0.5 p< 0.01). Weightlifters however did not demonstrate an age related decline in either systolic or diastolic annular velocities. Runners had no age related decline in systolic annular velocities, and whilst they had an age dependent fall in ETDE ( r = - 0.62 p < 0.05) the older runners ETDE were still significantly faster (p < 0.05) than that seen in control subjects. Study four investigated relationship between mitral annular velocity and VOiruK in runners, weightlifters and controls. These results demonstrated peak exercise E TDE strongly correlated to VO^PEAK (r = 0.8 p < 0.01). ConclusionsTaken together these data suggest that longitudinal velocities of the mitral annulus may be useful in determining the nature of increases in heart size, in addition the increased performance of endurance - trained athletes is due in part to functional changes of the long axis.

Made available in DSpace on 2015-07-22T20:50:24Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-03-25. Added 1 bitstream(s) on 2015-08-11T03:25:40Z : No. of bitstreams: 1 Publico-057a.pdf: 1544247 bytes, checksum: d76c2d7c07bfd1b50436489da9d22288 (MD5). Added 1 bitstream(s) on 2015-08-11T03:25:40Z : No. of bitstreams: 2 Publico-057a.pdf: 1544247 bytes, checksum: d76c2d7c07bfd1b50436489da9d22288 (MD5) Publico-057b.pdf: 1030631 bytes, checksum: 9562ff77059213eafe1900cb95553c45 (MD5) / Objetivo:Estabelecer o diagnóstico da hipertrofia ventricular esquerda(HVE)em pacientes com doença renal crônica(DRC)em programa de hemodiálise(HD)por sete diferentes critérios eletrocardiográficos, assim como pela radiografia de tórax,correlacionando estes dois métodos propedêuticos com o índice de massa do ventrículo esquerdo (IMVE)obtido pelo ecocardiograma.Métodos:Estudo transversal que incluiu 100 pacientes(58 homens e 42 mulheres,idade média de 46,2 ± 14,0 anos)com DRC de todas as etiologias,há pelo menos seis meses em HD.Foram obtidos ecocardiograma,eletrocardiograma e radiografia de tórax dos pacientes,sempre até uma hora após o término das sessões de HD.Resultados:A HVE foi detectada em 83pacientes(83 por cento),dos quais 56 (67,4 por cento)apresentavam o padrão concêntrico e 27(32,6 por cento)o padrão excêntrico de HVE.O tempo médio dos pacientes em HD foi de 50,7 ± 46,5 meses, mediana de 33,5 meses.A média do IMVE foi de 154,9± 57,3 g/m2.Todos os métodos eletrocardiográficos estudados e o índice cardiotorácico(ICT)apresentaram sensibilidade,especificidade e acurácia diagnósticas acima de 50 por cento.Pela correlação linear de Pearson com o IMVE apenas o critério de Sokolow-Lyon voltagem não apresentou coeficiente ≥ 0,50.Já o cálculo da razão de verossimilhança mostrou que o tanto o ECG como a radiografia de tórax possuem poder discriminatório para diagnóstico de HVE na população estudada,com ênfase para os critérios de Cornell produto e Romhilt-Estes.Não houve correlação entre o IMVE com o intervalo QTc e sua dispersão.Conclusões:O eletrocardiograma e a radiografia de tórax são métodos seguros,úteis,eficazes e de alta reprodutibilidade no diagnósticode HVE dos pacientes em HD.A utilidade do ECG é realçada pela capacidade de detectar alterações eletrofisiológicas,como o intervalo QTc e sua dispersão. / Objective: To establish the diagnosis of left ventricular hypertrophy (LVH) in haemodialysis (HD) patients with chronic kidney disease (CKD) using seven different electrocardiographic criteria and chest radiography, and to correlate these two diagnostic methods with left ventricular mass index (LVMI) as obtained by echocardiogram. Methods: Cross-sectional study including 100 patients (58 men and 42 women, mean age of 46.2 ± 14.0 years) with CKD of all causes, undergoing HD for at least six months. Echocardiogram, electrocardiogram and chest radiography were obtained from all patients, always up to one hour after the end of the HD sessions. Results: LVH was detected in 83 patients (83%), of which 56 (67.4%) presented a concentric pattern and 27 (32.6%) an eccentric pattern of LVH. The patients had been undergoing HD for a mean time of 50.7 ± 46.5 months, median of 33,5 months. The mean LVMI was 154.9 ± 57.3 g/m2. All electrocardiographic methods studied and the cardiothoracic ratio (CTR) had diagnostic sensitivity, specificity and accuracy higher than 50%. Using Pearson’s linear correlation with LVMI, only the Sokolow-Lyon voltage criterion did not present a 0.50 coefficient. The calculation of the likelihood ratio, in turn, showed that both ECG and chest radiography have a discriminatory power for the diagnosis of LVH in the population studied, with emphasis on for the Cornell product and Romhilt-Estes criteria. No correlation was found between LVMI and QTc and QTc dispersion. Conclusions: Electrocardiogram and chest radiography are safe, useful, efficient and highly reproducible methods for the diagnosis of LVH in HD patients. The usefulness of ECG is stressed by its ability to detect electrophysiological changes such as QTc and QTc dispersion. / TEDE / BV UNIFESP: Teses e dissertações

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Agradecemos a compreensão. on 2017-07-26T19:10:07Z (GMT) / Submitted by JULIANE ROSA POIATI null (jpoiati@yahoo.com.br) on 2017-07-27T00:19:47Z No. of bitstreams: 1 Tese Pronta recente.pdf: 1203025 bytes, checksum: 3f33e46e228494eaa8c4c9ba0d1246d1 (MD5) / Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-07-31T14:34:20Z (GMT) No. of bitstreams: 1 poiati_jr_dr_bot.pdf: 1203025 bytes, checksum: 3f33e46e228494eaa8c4c9ba0d1246d1 (MD5) / Made available in DSpace on 2017-07-31T14:34:20Z (GMT). No. of bitstreams: 1 poiati_jr_dr_bot.pdf: 1203025 bytes, checksum: 3f33e46e228494eaa8c4c9ba0d1246d1 (MD5) Previous issue date: 2017-05-26 / Objetivo: Determinar o valor da concentração do BNP que se associa à presença de hipertrofia do ventrículo esquerdo (VE) em mulheres com pré-eclâmpsia (PE). Métodos: Realizou-se estudo observacional, descritivo e transversal em gestantes com diagnóstico de pré-eclâmpsia, que receberam assistência obstétrica no Hospital das Clínicas da Faculdade de Medicina de Botucatu - Unesp. Foram excluídas do estudo gestantes portadoras de patologia clínica ou gestacional associada a alterações cardiovasculares (diabetes, hipertensão arterial crônica, cardiopatias, colagenoses, nefropatias). Considerando a prevalência de hipertrofia concêntrica do VE nessa população de 27% e assumindo a margem de erro de 10% e confiabilidade de 95%, o tamanho amostral calculado foi de 76 gestantes. No momento do diagnóstico de PE as gestantes selecionadas foram submetidas à coleta de sangue venoso para determinação da concentração sérica de BNP e ao exame de ecocardiograma para identificação de hipertrofia concêntrica do VE. As correlações entre o índice de massa do VE (iMVE) e entre a espessura relativa da parede (ER) e o BNP foram realizadas pelo teste de Spearman. O ponto de corte da concentração do BNP, que identifica hipertrofia concêntrica do VE, foi estabelecido pela curva ROC, utilizando-se o programa estatístico SPSS for Windows. Resultados: A hipertrofia concêntrica do ventrículo esquerdo foi diagnosticada em 48,7% das gestantes. O ponto de corte do valor da concentração do BNP, que identifica a hipertrofia concêntrica do VE, foi 203pg/mL (sensibilidade de 88%, especificidade de 80%, valor preditivo positivo de 69%, valor preditivo negativo de 93% e acurácia de 83%). A área sob a curva foi 0,87 (IC 95%= 0,79 – 0,95). A correlação entre o iMVE e a ER com a concentração do BNP foi significativa (iMVE: r=0,49; p<0,0001; ER: r=0,50; p<0,0001). Conclusões: O presente estudo encontrou correlação positiva entre os valores de BNP e hipertrofia do VE, além de determinar o ponto de corte (203 pg/ml) para o diagnóstico dessa condição. Utilizar o BNP como rastreamento de hipertrofia do VE pode ajudar na racionalização da indicação do ecocardiograma para confirmação diagnóstica. / Objective: To determine BNP concentration value associated with the presence of left ventricular hypertrophy (LV) in women with pre-eclampsia (PE). Methods: An observational, descriptive and cross-sectional study was performed in pregnant women diagnosed with preeclampsia, who have received obstetric care at Botucatu Medical School Clinical Hospital - Unesp. Pregnant women with clinical or gestational pathology associated with cardiovascular alterations such as diabetes, chronic hypertension, heart diseases, collagenosis, nephropathies were excluded from the study. Considering the prevalence of LV concentric hypertrophy in this population of 27% and assuming the margin of error of 10%, as well as reliability of 95%, the calculated sample size was of 76 pregnant women. At the moment of PE diagnosis the selected pregnant women were submitted to both venous blood collection (in order to determine BNP serum concentration) and to echocardiogram examination (to identify LV concentric hypertrophy). Correlations between LV mass index (iMVL), relative wall thickness (WT) and BNP were performed with Spearman test. The cut off of BNP concentration, which identifies LV concentric hypertrophy, was established with ROC curve, using the statistical program SPSS for Windows. Results: Left ventricular concentric hypertrophy was diagnosed in 48.7% of the pregnant women. The cut off value of BNP concentration, which identifies LV concentric hypertrophy, was 203pg / mL (sensitivity 88%, specificity 80%, positive predictive value 69%, negative predictive value 93%, and accuracy 83%). The area under the curve was 0.87 (95% CI = 0.79-0.95). The correlation between iMVL and WT with BNP concentration was significant (iMVE: r=0,49; p<0,0001; ER: r=0,50; p<0,0001). Conclusions: The present study found a positive correlation between BNP values and LV hypertrophy. Moreover, it determined the cut off (203 pg / ml) for the diagnosis of this condition. Therefore, using BNP as a screening method for LV hypertrophy may help to rationalize echocardiographic indication for diagnosis confirmation.

O remodelamento cardíaco é uma sequela da hipertensão. Receptores do tipo Toll (TLRs) pertencem a imunidade inata e sua ativação produz moléculas inflamatórias. O objetivo do trabalho foi avaliar a participação do TLR4 no remodelamento cardíaco de ratos espontaneamente hipertensos (SHR). Utilizamos SHR e Wistar de 6 e 21 semanas. O nível do RNAm do TLR4 de SHR de 21 semanas é maior em relação aos outros grupos. Outros grupos de Wistar e SHR de 19 semanas foram tratados com anticorpo anti-TLR4, os controles receberam anticorpo IgG inespecífico. Observamos redução no nível do RNAm do TLR4 e MyD88 e expressão protéica do TLR4, MyD88, TNF-<font face=\"symbol\">a e IL-1<font face=\"symbol\">b de SHR anti-TLR4 em relação aos SHR controle. Não houve alteração nos valores pressóricos. Verificamos redução no nível do RNAm de colágenos I e III, de metaloproteinases 2 e 9, de ANP, BNP e <font face=\"symbol\">a-actina esquelética e de deposição de colágeno, área e diâmetro de cardiomiócitos de SHR anti-TLR4 em relação aos SHR controle. Nossos resultados sugerem que o TLR4 participa do processo de remodelamento cardíaco de SHR adultos. / The cardiac remodeling is a sequel of hypertension. Toll-Like Receptors (TLR) are innate immunity receptor and its activation produces inflammatory molecules. The objective of this study was to evaluate the involvement of TLR4 in cardiac remodeling of spontaneously hypertensive rats (SHR). We used male Wistar and SHR with 6 and 21 weeks. The level of TLR4 mRNA in SHR with 21 weeks is higher than the other groups. Wistar and SHR with 19 weeks were treated with anti-TLR4 or nonspecific IgG antibody (control group). We observed a reduction in the level of TLR4 and MyD88 mRNA and protein expression of TLR4, MyD88, TNF-<font face=\"symbol\">a and IL-1<font face=\"symbol\">b in anti-TLR4 SHR compared to control SHR. There was no change in blood pressure values in SHR after anti-TLR4 treatment. We observed reduction in mRNA level of collagens I and III, metalloproteinases 2 and 9, ANP, BNP, <font face=\"symbol\">a-skeletal actin, collagen deposition, cardiomyocyte area and diameter in anti-TLR4 SHR compared to control SHR. Our results suggest that TLR4 participates of cardiac remodeling process in adults SHR.

Orientador: Heitor Moreno Junior / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-20T00:15:25Z (GMT). No. of bitstreams: 1 Ludovico_NelsonDinamarco_D.pdf: 11127350 bytes, checksum: fac2a775e3c6969068fdbd9ca7d14542 (MD5) Previous issue date: 2012 / Resumo: A hipertrofia ventricular esquerda caracterizada como lesão de órgão alvo aumenta o risco de morbi-mortalidade de 5 a 9 vezes quando presente. A detecção precoce da HVE permite a identificação de pacientes com risco, além de permitir a intervenção de forma precoce, melhorando o planejamento estratégico para o seu manejo. A hipertensão arterial resistente é caracterizada pelo paciente, que mesmo em uso de três medicações em doses otimizadas, sendo um deles diurético, ainda se mantém fora das metas preconizadas. Vários métodos diagnósticos de hipertrofia estão disponíveis para o diagnóstico da HVE, entre eles se destaca o ecocardiograma com elevada sensibilidade, especificidade e acurácia, o eletrocardiograma, com elevada especificidade, porém baixa sensibilidade e acurácia, em contrapartida com excelente reprodutibilidade e baixo custo operacional, e fácil realização, inclusive em locais afastados dos grandes centros, em contraposição ao ecocardiograma. Outro método, não muito usado na prática clínica, o vetorcardiograma, pode atualmente, ser realizado no mesmo equipamento do eletrocardiograma, justificando assim a sua empregabilidade na prática clínica diária. Apresentou em nosso estudo a mesma baixa sensibilidade e acurácia que o eletrocardiograma, compatíveis com estudos publicados recentemente, porém a associação de dois critérios, um eletrocardiográfico e outro vetorcardiográfico melhorou a sensibilidade e acurácia na detecção da hipertrofia ventricular esquerda, sem prejuízo para a especificidade, com valores próximos ao ecocardiograma / Abstract: Left ventricular hypertrophy characterized as target-organ damage increases the risk of morbidity and mortality 5-9 times when present. Early detection of LVH allows the identification of patients at risk, and allows intervention at an early stage, improving strategic planning for its management. The resistant hypertension is characterized by the patient, even taking three medications in doses optimized, one being a diuretic, is still outside of the recommended goals. Several diagnostic methods are available to hypertrophy the diagnosis of LVH, including echocardiography stands out with high sensitivity, specificity and accuracy, the electrocardiogram, with high specificity but low sensitivity and accuracy, in contrast with excellent reproducibility and low operating cost, and easy to perform, even in places far from the large centers, in contrast echocardiography. Another method, not widely used in clinical practice, the vectorcardiogram, can now be performed on the same equipment on the electrocardiogram, thereby justifying their employability in daily clinical practice. In our study vectorcardiography presented the same low sensitivity and accuracy than electrocardiography, consistent with recently published studies, but the combination of two criteria, an electrocardiogram and other vetorcardiográfico improved sensitivity and accuracy in detecting left ventricular hypertrophy, without prejudice to the specificity, with values close to echocardiography / Doutorado / Farmacologia / Doutor em Farmacologia

Introduction : Le diagnostic de cardiomyopathie hypertrophique (CMH) est difficile chez l’athlète. En effet, le remodelage physiologique induit par l’entraînement physique intense entraîne des modifications électriques et morphologiques qui peuvent mimer une cardiomyopathie. Or il est indispensable de poser le diagnostic de cardiomyopathie avec certitude chez un athlète. Ne pas contre-indiquer un athlète avec une cardiomyopathie l’expose à un risque de mort subite, mais poser un diagnostic par excès l’expose à de lourdes répercussions tant professionnelles que sociales. Méthodes : (1) Nous avons cherché à améliorer les critères ECG actuels de détection de cardiomyopathie chez l’athlète à partir d’une cohorte multicentrique d’athlètes et de CMH. (2) Nous avons cherché à déterminer quel bilan complémentaire réaliser en cas d’anomalie ECG par un suivi longitudinal d’athlètes avec ondes T négatives. (3) Nous avons essayé de mieux caractériser le phénotype des athlètes atteints de CMH par rapport aux CMH sédentaires dans une cohorte multicentrique. (4) Nous avons tenté de déterminer si l’utilisation des nouvelles techniques d’imagerie de déformation myocardique permettait d’améliorer la pertinence diagnostique et pronostique en cas de CMH dans une cohorte de CMH et d’athlètes rennais. Résultats : Nous avons proposé une nouvelle classification ECG permettant de mieux identifier les athlètes avec modifications ECG non pathologiques sans diminuer pour autant la capacité à détecter les CMH. En cas d’ondes T négatives chez l’athlète, nous avons démontré qu’il était indispensable de réaliser une IRM myocardique. En effet l’échocardiographie peut être prise en défaut dans près de 35% des cas. Néanmoins, les critères diagnostiques actuels de CMH peuvent être pris en défaut; en effet les athlètes avec une CMH ont un phénotype différent des CMH sédentaires avec une meilleure fonction systolique, notamment longitudinale, et diastolique. L’évaluation de la fonction longitudinale à l’effort et l’évaluation de la dispersion mécanique sont des paramètres qui semblent prometteurs en terme de diagnostic. En effet l’altération la fonction longitudinale semble être en lien avec la fibrose myocardique. L’échocardiographie d’effort, notamment la présence d’une insuffisance mitrale à l’effort, semble être un facteur pronostic important dans les CMH. Conclusions : les travaux réalisés ont permis de développer des outils pour mieux différencier une hypertrophie ventriculaire gauche (HVG) pathologique d’une HVG physiologique mais également pour mieux caractériser cette HVG et déterminer avec plus de précision le pronostic des CMH . / Introduction: the diagnosis of hypertrophic cardiomyopathy (HCM) in athlete is difficult. Indeed, intense sports practice induces an electrical and morphological physiological remodeling which can be difficult to differentiate from the changes induced in pathology. However, it is essential to diagnose an athlete with a cardiomyopathy. Indeed, in case of underlying cardiomyopathy the athlete will be at risk of sudden cardiac death, but an excessive over diagnosis has strong professional and social consequences. Methods: (1) we have tried to improve the ECG criteria’s, which enable the differentiation between ECG changes induced by exercise and the ECG changes induced by an underlying cardiomyopathy. (2) We tried to define the best investigation algorithm in case of abnormal ECG changes in athletes. (3) We tried to improve the characterization of the phenotype of athletes with HCM as compared to sedentary HCM. (4) We tried to investigate if the use of new imaging technics, i.e. speckle tracking, might improve the diagnostic accuracy and enable a better prognostic evaluation in HCM. Results: We have proposed a new classification of ECG in athletes enabling to decrease the rate of false positive ECG in athletes without decreasing its diagnostic accuracy in HCM. In case of pathological T wave inversion (PTWI) in athletes, we demonstrated that a CMR is mandatory, as echocardiography missed a diagnosis of pathology in 35% of PTWI athletes. Nevertheless, the diagnosis of HCM with current criteria’s of HCM can be challenging. Indeed, HCM athletes have a different phenotype from HCM sedentary, with a better systolic and diastolic function; they also have a better longitudinal function. The assessment of longitudinal function during exercise and mechanical dispersion are promising tool for the diagnosis of HCM in athletes. Indeed, the alteration of longitudinal strain is related to myocardial fibrosis. Exercise echocardiography, i.e. exercise mitral insufficiency, seems to be a prognostic factor in HCM patients. Conclusions: Ours results enabled to develop tools which might help to better differentiate pathological and physiological left ventricular hypertrophy (LVH); but also to better characterize LVH and the prognosis in HCM patients.

Made available in DSpace on 2016-05-02T13:54:45Z (GMT). No. of bitstreams: 1 GerusaDiasSiqueiraTerra-dissertacao-completa.pdf: 368963 bytes, checksum: e83d124cb3bda742ff64fecbae0111b8 (MD5) Previous issue date: 2010-07-21 / Regular physical activity combined with healthy eating habits are important factors in primary prevention and therapeutic support in cardiovascular diseases, such as dyslipidemia and left ventricular hypertrophy, which are outstanding risk indicators of cardiovascular morbidity and mortality. This study assessed the effects of swimming on the lipid profile and left ventricular structures in hyperlipidemic mice. Twenty-eight male LDLr-/- mice were randomly separated into 4 groups: sedentary, fed a standard diet (S); exercising, fed a standard diet (E+Nat); sedentary, fed a hyperlipidic diet (S+HL); and exercising, fed a hyperlipidic diet (E+HL). The exercising mice swam daily for 60 minutes during 60 days. Blood was collected for measuring the plasma levels of triglycerides, total cholesterol and its fractions (LDL, HDL, VLDL). The heart was removed and the left ventricle was weighed fresh to calculate the ratio left-ventricle weight (mg)/body weight (g). The results showed that swimming was more effective in improving lipid plasma levels when combined with a balanced diet, thereby confirming that it is essential to associate physical exercise and diet. Swimming resulted in eccentric left ventricular hypertrophy in the standard-diet group and decreased interstitial collagen deposition in the myocardium of the high-fat-diet animals, which may indicate an improved diastolic function with consequent improvement in the systolic function. It was concluded that regular aerobic exercise induce cardiac adaptations that improve whole body physiology by promoting health and preventing diseases. However, it is extremely important to note that exercise should be regular and associated with an adequate diet. / A prática de atividade física regular, associada a hábitos alimentares saudáveis são fatores importantes na prevenção primária e no suporte terapêutico das doenças cardiovasculares, dentre as quais as dislipidemias e a hipertrofia ventricular esquerda, que representam indicadores de grande relevância no risco de morbidade e mortalidade cardiovascular. O objetivo do presente estudo foi o de analisar os efeitos da natação no perfil lipídico e nas estruturas ventriculares esquerdas de camundongos hiperlipidêmicos. Foram utilizados 28 camundongos LDLr-/-, machos, divididos aleatoriamente em 4 grupos: sedentários alimentados com ração padrão (S); treinados alimentados com ração padrão (S+Nat), sedentários alimentados com ração hiperlipídica (HL) e treinados alimentados com ração hiperlipídica (HL+Nat). Os animais dos grupos treinados praticaram natação em intensidade moderada, por 60 minutos durante 60 dias consecutivos. O sangue foi coletado e o soro utilizado para análises laboratoriais de triglicérides, colesterol total e suas frações (LDL, HDL, VLDL). O coração foi removido e somente o ventrículo esquerdo foi pesado a fresco para se calcular a proporção do peso ventricular esquerdo (mg)/ peso do animal (g). Os resultados mostraram que a natação foi mais eficiente na melhora dos níveis plasmáticos de lipídeos quando acompanhada por uma dieta adequada, confirmando que a associação exercício físico com dieta equilibrada é essencial para obtenção de seus benefícios. A natação ocasionou hipertrofia ventricular esquerda excêntrica no grupo alimentado com dieta padrão e, principalmente, diminuiu o depósito de colágeno intersticial no miocárdio dos animais alimentados com dieta hiperlipídica, o que pode indicar uma melhora na função diastólica com consequente melhora da função sistólica. Concluiu-se que a prática de exercícios aeróbicos regulares induz adaptações cardíacas que melhoram o funcionamento do organismo, promovendo saúde e prevenindo doenças. Contudo é de suma importância observar que sua prática deve ser regular e associada a uma dieta adequada.

No presente estudo, duas importantes situações foram abordadas no intuito de se melhor entender os mecanismos homeostáticos dos pressorreceptores na gênese da hipertrofia cardíaca em resposta à hipertensão renovascular: o efeito do tempo de clipe na artéria renal e o efeito dos níveis pressóricos e da variabilidade da pressão arterial. O curso temporal mostrou que, antes mesmo da instalação da hipertensão, há alteração da morfologia cardíaca, qual seja o desenvolvimento de uma hipertrofia ventricular excêntrica e, como forma de mecanismo compensatório, um aumento da expressão de algumas proteínas da homeostase do cálcio (fosfolambam fosforilada pela serina-16 e corrigido pelo fosfolambam total em 100% e fosfolambam fosforilado pela treonina-17 e corrigido pelo fosfolambam total em 54%). Uma vez instalada a hipertensão, observou-se um remodelamento ventricular esquerdo para o tipo concêntrico, com prejuízo da função diastólica e um desbalanço do sistema nervoso autonômico, com aumento da atividade simpática, observado pelo aumento da razão dos componentes de baixa freqüência (LF) e alta freqüência (HF) no tacograma (0,44 ± 0,10 vs. 0,20 ± 0,03 nos controles). A análise do efeito da pressão arterial e da variabilidade da pressão arterial mostrou uma correlação positiva com o grau de hipertrofia ventricular esquerda (r=0,76, p<0,01). A secção cirúrgica dos pressorreceptores somada à implantação do clipe na artéria renal mostrou adaptações cardiovasculares em níveis semelhantes (mesmo nível de hipertensão) e, por vezes maiores (modulação simpática para o coração e para os vasos, hipertrofia ventricular esquerda e disfunção diastólica), ao grupo cuja artéria renal foi estenosada e que permaneceu com os barorreceptores intactos. Estas respostas aconteceram num período de tempo três vezes menor na ausência do barorreflexo. Tais observações ressaltam o importante efeito homeostático do barorreflexo na gênese das respostas cardíacas adaptativas à hipertensão arterial / In the present study, two important situations were observed to evaluate the role of the baroreceptors in the genesis of cardiac hypertrophy in response to hypertension: the effect of the time-course of the clip in the renal artery and the effect of the level of arterial blood pressure (ABP) and blood pressure variability (ABPV). The time-course evaluation showed that even before hypertension was installed, cardiac alterations could be observed, as a left ventricular eccentric hypertrophy. Compensatory mechanisms, such as an increase in some calcium homeosthatic proteins, could also be noticed (increase in phosphorilated phospholmaban at threonin-17 corrected by total phospholamban in 54% and increase in phosphorilated phospholmaban at serine-16 corrected by total phospholamban in 100%). However, once hypertension was established, left ventricle morphology changed to a concentric hypertrophy, accompanied by a diastolic dysfunction and enhanced sympathetic modulation, observed by relation between low-frequency component (LF) and high-frequency component (HF) at tachogram (0,44 ± 0,10 vs. 0,20 ± 0,03 in control group). ABP and ABPV analyses showed an important positive correlation with the degree of left ventricular hypertrophy (r=0,76, p<0,01). However, the absence of baroreceptors in one of the hypertensive groups, evoked the same cardiovascular alterations (same level of hypertension) or even worse (sympathetic modulation for heart and vessels, left ventricular hypertrophy and diastolic dysfunction) reached by the hypertensive baroreceptors-preserved group. These cardiovascular responses were observed in a period that correspond one third of time to the group with intact baroreflex. These observations lead us to conclude the importance of homeosthatic effects of the baroreflex in the genesis of cardiac responses to hypertension

Activation of NF-κB contributes to cardiac hypertrophy and the interleukin-1 receptor (IL-1R)-mediated MyD88-dependent signaling pathway predominately activates NF-κB. Recent studies have shown that the TIR/ BB-Loop mimetic (AS-1) disrupted the interaction of MyD88 with the IL-1R, resulting in blunting of NF-κB activation. We have examined the effects of AS-1 on the IL-1b-induced hypertrophic response using cultured neonatal cardiac myocytes in vitro and transverse aortic constriction (TAC) pressure overload-induced cardiac hypertrophy in vivo. Neonatal cardiac myocytes were treated with AS-1 15 min prior to IL-1β stimulation for 24 h. AS-1 treatment significantly attenuated IL-1β-induced hypertrophic responses of cardiac myocytes. In vivo experiments showed that AS-1 administration prevented cardiac hypertrophy and dysfunction induced by pressure overload. AS-1 administration disrupted the interaction of IL-1R with MyD88 in the pressure overloaded hearts and prevented activation of NF-κB. In addition, AS-1 prevented increases in activation of the MAPK pathway (p38 and p-ERK) in TAC-induced hypertrophic hearts. Our data suggest that the IL-1R-mediated MyD88-dependent signaling pathway plays a role in the development of cardiac hypertrophy and AS-1 attenuation of cardiac hypertrophy is mediated by blocking the interaction between IL-1R and MyD88, resulting in decreased NF-κB binding activity and decreased MAPK activation.