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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Performance du ventricule gauche chez le sujet hypertendu : étude biomécanique par modélisation du couplage ventriculo-aortique / Left ventricular performance in hypertension : left ventricular-arterial coupling by biomechanical modeling

Bonnet, Benjamin 12 February 2016 (has links)
Introduction : Les paramètres éjectionnels d’évaluation de la fonction ventriculaire gauche, sont directement influencés par la post-charge. Dans ce contexte chez l’hypertendu, une analyse complète de la performance du ventricule gauche (VG) doit pouvoir intégrer des paramètres hémodynamiques (variations de volume du VG vs variations de pressions aortique) mais aussi des paramètres de «déplacement » des parois. L’objectif de cette thèse est de déterminer avec des techniques non invasives le couplage ventriculo-aortique chez l’hypertendu.Méthodes : Les courbes de pression-volume ont été obtenues par échographie 3D en temps réel pour les volumes et tonométrie pour la pression carotidienne. A partir des boucles pression-volume, une méthode des moindres carrés non linéaire est utilisée pour construire la droite d’élastance. Le couplage ventriculo-aortique est estimé par le rapport de l’élastance télé-systolique de sortie du VG (Ees) et d’entrée aortique (Ea). Le transfert d’énergie du VG à l’aorte (rendement) est calculé par le rapport de la puissance d’éjection et de la puissance de déformation myocardique.Résultats : L’étude de validation de notre nouvelle méthode de modélisation d’Ees montre une bonne sensibilité et reproductibilité par rapport aux méthodes invasives de référence. Outre sa précision, l’avantage de notre méthode est la simplicité de son application clinique. Les premiers résultats de ce travail montrent que à un stade précoce de l’HTA, l’augmentation simultanée de la puissance d’éjection et d’Ea est compensée par une augmentation du rendement du VG et d’Ees pour un couplage ventriculo-aortique qui reste préservé.Conclusion : Le travail de modélisation de la relation pression-volume de cette thèse a permis son application clinique sur une population de sujets hypertendus. Ces premiers résultats positifs ont permis la mise en place d’une étude randomisée sur l’influence de l’apport sodé sur le couplage ventriculo-aortique chez l’hypertendu. L’avantage de cette nouvelle méthode de calcul d’Ees, basée sur l’échocardiographie 3D en temps réel, permet de se passer de toutes les hypothèses géométriques qui étaient jusqu’alors nécessaires pour les études en imagerie bidimensionnelle. Le recours à l'imagerie reste en revanche plus complexe pour l’analyse des déplacements en 3D qui nécessitent encore un travail de modélisation. / Introduction : In addition to contractility, afterload is one of the main determinants of left ventricular (LV) performance. Thus, analysis of LV function in hypertension not only requires incorporation of hemodynamics parameters such as LV time-varying volume and pressure, but also LV wall strain and stress. The aim of the present study is to evaluate non invasively LV-arterial coupling in hypertension.Method : LV volumes and pressures curves were obtained from real-time 3D echocardiography (RT3DE) and carotid tonometry, respectively. The pressure-volume (P-V) curves thus obtained were fitted with a non linear least squares method. We then computed the slope and the intercept of time varying élastance, and volume intercept V0. LV-aortic coupling is estimated by the ratio of LV and aortic elastance (Ees and Ea). Energy transfer from the left ventricle to aorta is defined as the ratio of external work and myocardial strain work (Pmeca). Cyclic variations of wall thickness and strain rate were measured by 2D speckle-tracking. Pmeca was calculated according to the produce of LV wall stress with strain rate.Result : A good univariate relationship and a good agreement were found between previous invasive calculation of Ees and our new proposed “Ejection P-V Curve” method. In hypertensive patients, increase in Ea and LV efficiency were compensated by a parallel increase in Ees without change in Ea/EesConclusion : Ees and V0 can be estimated non invasively from modeling of the P-V curve during ejection. This approach was found to be reproducible and sensitive enough to detect an expected difference in LV contractility in hypertensive patients. Due to its non invasive nature, our new proposed “Ejection P-V Curve” method is now applicable to a randomized study of the effect of sodium intake on LV performance in hypertension. Among strengths of these new methods based on RT3DE, is to exclude the necessity of geometrics assumptions for the evaluation of LV volumes. However, 3D analysis of LV strain is not yet fully-developed, with the necessity to improve the performance of frame acquisition and modeling.
82

Comparison of carotid plaque characteristics, arterial remodelling changes, left ventricular geometry and inflammatory markers in patients with chest pain and unobstructed coronary arteries, chronic stable angina or acute coronary syndromes

Balakrishnan Nair, Satheesh January 2013 (has links)
Introduction: Atherosclerosis remains asymptomatic until it progresses to cause flow-limiting disease. Identifying patients at high risk in the early stages of the atherosclerotic process may allow modification of cardiovascular risk by effective preventive strategies. Various non-invasive tests have been studied and have shown promising results in predicting future adverse cardiovascular events. The objective of this study was to establish the carotid ultrasonographic markers that best correlate with angiographic coronary artery disease (CAD) and the relationship between left ventricular geometry, carotid atherosclerosis, biomarkers and CAD in patients with unobstructed coronary arteries, chronic stable angina (CSA) and acute coronary syndromes (ACS). Methods: Carotid ultrasound examination, echocardiography and serum biomarker estimation were performed in consecutive patients who underwent coronary angiography for evaluation of stable or acute chest pain. Results: A total of 146 subjects were recruited into the study with a mean age of 56.9 ± 10.6 (range 29 to 85) years; 120 were men (82%) and 26 (18%) women. Twenty-one percent of the study population had unobstruced coronaries, 42% had stable CAD and 37% had presented with ACS. There was no significant difference in the carotid intima media thickness (CIMT) measurements between the three groups. CIMT correlated with abnormal left ventricular geometry but not with the presence or severity of CAD. The presence of carotid plaque and plaque score correlated with obstructive CAD, but was not significantly different between stable CAD and ACS patients. There was a trend towards more echogenic plaque in the stable CAD group. The composite score of IMT and plaque was positively correlated with the presence and severity of CAD. The averaged myocardial peak systolic and early diastolic velocities were significantly lower in those with obstructive CAD. CRP and osteopontin levels were higher in the ACS patients. Conclusions: Carotid plaque and not CIMT was associated with angiographic coronary artery disease. Averaged systolic and early diastolic myocardial velocities by tissue doppler imaging correlated with obstructive CAD. Novel serum biomarkers are promising and further studies are needed.
83

Hypertrophie ventriculaire gauche physiologique ou pathologique : Intérêt d’une approche multiparamétrique / Physiological or pathological left ventricular hypertrophy : interest of a multi-parametric approach

Schnell, Frédéric 17 November 2015 (has links)
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.
84

Interações do polimorfismo -930A/G da p22phox em pacientes hipertensos / Interactions of p22phox -930A/G polymorphism in hypertensive patients

Sales, Maria Lilian 22 August 2006 (has links)
Orientador: Wilson Nadruz Junior / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-07T22:16:04Z (GMT). No. of bitstreams: 1 Sales_MariaLilian_M.pdf: 699325 bytes, checksum: c06952a4445a0175323db1f2dd969bed (MD5) Previous issue date: 2006 / Resumo: A subunidade p22phox é um componente essencial do complexo enzimático NADPH oxidase, o qual é considerado a principal fonte de produtos do stress oxidativo no sistema cardiovascular. O alelo -930G da p22phox tem sido associado com maior stress oxidativo mediado pela NADPH oxidase e hipertensão arterial. Nós recentemente demonstramos que a hipertrofia do ventrículo esquerdo é acompanhada de aumento na expressão miocárdica de p22phox em ratos submetidos à coarctação da aorta, sugerindo que esta proteína pode estar envolvida em lesões de órgão-alvo induzidas por hipertensão, mais especificamente na hipertrofia cardíaca. Foi pesquisada a prevalência deste polimorfismo em 160 indivíduos acompanhados no Ambulatório de Hipertensão Arterial Sistêmica da UNICAMP, e realizada a correlação desta variante com a massa e geometria ventricular esquerda, lesão renal e perfil metabólico destes pacientes. Não foram encontradas correlações significativas entre este polimorfismo e lesão renal ou estrutural em ventrículo esquerdo. Porém, nos indivíduos com genótipo GG foram encontrados níveis séricos de Triglicérides e de LDL colesterol significativamente mais baixos / Abstract: The p22phox subunit is an essential component of the NAD(P)H oxidase enzymatic complex, which is considered the major source of oxidative stress products in the cardiovascular system. The -930G allele of p22-phox has been associated with higher promoter activity, increased NAD(P)H oxidase-mediated oxidative stress and hypertension. NADPH oxidases have been proved important in the pathogenesis of renal damage in models of hypertension. We recently reported that left ventricular hypertrophy is accompanied by increased myocardial p22-phox expression in aortic-banded rats, suggesting that this protein might be involved in hypertensive cardiac hypertrophy. Thus, the aim of the present report was to investigate the role of p22phox -930A/G polymorphism on cardiac hypertrophy, renal damage and metabolic profile in hypertensive patients. We research the -930A/G polimorfism prevalence in 160 hypertensive subjects from Ambulatory Hypertension Unit - UNICAMP. The follow-up was between 2005 and 2006. The variant -930A/G has not relationship with alterations in ventricular structure and with renal damage markers. However, in GG subjects was associated with lower seric levels of Triglycerides and LDL-cholesterol This finding suggest a association between this variant GG genotype with a best metabolic profile in hypertensives / Mestrado / Clinica Medica / Mestre em Clinica Medica
85

Influência dos barorreceptores e da pressão arterial na resposta cardíaca à hipertensão renovascular em ratos / Influence of baroreceptors and of arterial blood pressure in cardiac responses to renovascular hypertension in rats

Kaleizu Teodoro Rosa 15 August 2008 (has links)
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
86

Evaluation of systolic and diastolic left ventricular function during exercise in athletes

Bilal, Dejan January 2019 (has links)
Idrottshjärta är ett kardiovaskulärt tillstånd som uppträder under längre perioder av intensiv träning som orsakar strukturella, funktionella och elektriska förändringar hos hjärtat och är en fysiologisk anpassning som svar på ett ökat hemodynamiskt behov under fysisk ansträngning. De fysiologiska anpassningarna har dock blivit ett diagnostiskt dilemma att urskilja från de patologiska förändringarna såsom hypertrofisk kardiomyopati. Det finns därför ett behov av standardisering av kardiovaskulär screening hos idrottare för att upptäcka underliggande eller dolda kardiomyopatier som kan leda till allvarliga konsekvenser under fysisk ansträngning. Studiens ändamål var att undersöka den systoliska och diastoliska vänsterkammarfunktionen under ansträngning hos idrottare och öka förståelsen om vad som händer med de olika variablerna under arbete. Nio friska idrottare genomförde stressekokardiografi där cardiac index, ejektionsfraktion, fyllnadstryck, mitralisklaffplanets longitudinella rörelse (MAPSE), mitralisinflöde, vävnadsdoppler (e´ och s´) och veninflöde undersöktes före, under och efter ett ansträngningstest på ergometercykel. Variablerna under och efter cykeltestet jämfördes sedan med värdena i vila. Resultaten visade en signifikant ökning av cardiac index, MAPSE och vävnadsdoppler under ansträngning. Sammanfattningsvis visade studien att flera av variablerna förbättrades under ansträngning och en del av de visade sig vara relativt okänsliga för störningar och artefakter vilket kan vara användbart för framtida studie protokoll som avser utföra en hjärtstudie under arbete. / Athlete’s heart is a cardiovascular condition that occurs during extended periods of intense exercise that causes structural, functional and electrical changes of the heart and is a physiological adaptation in response to increased hemodynamic needs during physical exertion. However, the physiological adaptations have become a diagnostic dilemma to distinguish from the pathological changes such as hypertrophic cardiomyopathy. Therefore, there is a need for standardization of cardiovascular screening in athletes to detect underlying or hidden cardiomyopathies that can lead to severe consequences during physical exercise. The aim of the present study was to investigate the systolic and diastolic left ventricular function during exercise in athletes and to increase the understanding of what happens to the various variables during exertion. Nine healthy athletes conducted stress echocardiography where cardiac index, ejection fraction, filling pressure, mitral annular plane systolic excursion (MAPSE), mitral inflow, tissue Doppler imaging (e 'and s') and pulmonary venous inflow were examined before, during and after a cycle ergometer test. The variables during and after the cycle test were then compared to baseline. The results showed a significant increase in cardiac index, MAPSE, and tissue Doppler imaging during exertion. In conclusion, the study showed that several of the variables improved during exertion and some of them proved to be quite insensitive to disturbances and artifacts, which may be useful in future study protocols that consider carrying out a cardiac study during work.
87

Basic fibroblast growth factor attenuates left-ventricular remodeling following surgical ventricular restoration in a rat ischemic cardiomyopathy model / 塩基性繊維芽細胞増殖因子はラットの虚血性心筋症モデルにおいて左室形成術後の左室リモデリングを抑制する

Nagasawa, Atsushi 24 November 2020 (has links)
京都大学 / 0048 / 新制・論文博士 / 博士(医学) / 乙第13380号 / 論医博第2214号 / 新制||医||1047(附属図書館) / 京都大学大学院医学研究科外科系専攻 / (主査)教授 山下 潤, 教授 木村 剛, 教授 浅野 雅秀 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM
88

Impact of bridge-to-bridge strategies from paracorporeal to implantable left ventricular assist devices on the pre-heart transplant outcome: A single-center analysis of 134 cases / 体外設置型補助人工心臓から植込型左室補助人工心臓への移行が心臓移植待機中の予後に及ぼす影響:単一施設における134例の検討

Doi, Seiko 26 July 2021 (has links)
京都大学 / 新制・論文博士 / 博士(医学) / 乙第13428号 / 論医博第2232号 / 新制||医||1053(附属図書館) / (主査)教授 湊谷 謙司, 教授 佐藤 俊哉, 教授 福田 和彦 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM
89

Reversibility of severe mitral valve regurgitation after left ventricular assist device implantation single-centre observations from a real-life population of patients

Dobrovie, Monica 09 June 2020 (has links)
This study evaluates the impact of untreated preoperative severe mitral valve regurgitation (MR) on outcomes after left ventricular assist device (LVAD) implantation. Of the 234 patients who received LVAD therapy in the Heart Center Leipzig during a 6-year period, we selected those who had echocardiographic images of good quality and excluded those who underwent mitral valve replacement prior to or mitral valve repair during LVAD placement. The 128 patients selected were divided into 2 groups: Group A with severe MR (n = 65) and Group B with none to moderate MR (n = 63, 28 with moderate MR). We evaluated transthoracic echocardiography preoperatively [15 (7–28) days before LVAD implantation; median (interquartile range)] and postoperatively up to the last available follow-up [501 (283–848) days after LVAD]. We collected mortality, complications and clinical status indicators of the patient cohort. We observed a significant decrease in the severity of MR after LVAD implantation (severe MR 51% pre- vs 6% post-LVAD implantation, P < 0.001). There was no difference between groups in terms of right heart failure, rate of urgent heart transplantation, pump thrombosis or ventricular arrhythmias. There was no difference in 1-year survival and 3-year survival (87.7% vs 88.4% and 71.8% vs 66.6% for Groups A and B, respectively, P = 0.97). We concluded that preoperative severe MR resolves in the majority of patients early on after LVAD implantation and is not associated with worse clinical outcomes or intermediate-term survival.:Inhaltsverzeichnis Abkürzungsverzeichnis 3 1. Einführung 4 2. Formatierte Publikation 12 3. Zusammenfassung der Arbeit 19 4. Literaturverzeichnis 23 5. Anlagen 28 5.1. Statistical analysis of echocardiographic parameters in follow-up 28 5.2. Statistical Models Used 30 Darstellung des eignen wissenschaftlichen Beitrages 32 Erklärung über die eigenständige Abfassung der Arbeit 33 Lebenslauf 34 Publikationen 37 Danksagung 38
90

The TIR/BB-Loop Mimetic AS-1 Prevents Cardiac Hypertrophy by Inhibiting IL-1R-Mediated MyD88-Dependent Signaling

Zhu, Yun, Li, Ting, Song, Juan, Liu, Chunyang, Hu, Yulong, Que, Lingli, Ha, Tuanzhu, Kelley, Jim, Chen, Qi, Li, Chuanfu, Li, Yuehua 01 September 2011 (has links)
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.

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