Submitted by GABRIELA RONCADA HADDAD null (gabriela.haddad@yahoo.com) on 2017-09-10T22:08:03Z No. of bitstreams: 1 Tese Doutorado 27 jul 2017 - Gabriela.pdf: 1172239 bytes, checksum: d6ae9b8e2d02ba5890bf385b02539433 (MD5) / Approved for entry into archive by Monique Sasaki (sayumi_sasaki@hotmail.com) on 2017-09-12T16:46:39Z (GMT) No. of bitstreams: 1 haddad_gr_dr_bot.pdf: 1172239 bytes, checksum: d6ae9b8e2d02ba5890bf385b02539433 (MD5) / Made available in DSpace on 2017-09-12T16:46:39Z (GMT). No. of bitstreams: 1 haddad_gr_dr_bot.pdf: 1172239 bytes, checksum: d6ae9b8e2d02ba5890bf385b02539433 (MD5) Previous issue date: 2017-08-21 / Introdução: A influência do ácido retinoico (AR) sobre o coração é bastante relevante, ocorrendo durante a embriogênese, diferenciação e desenvolvimento cardíaco. Estudos experimentais mostram que o AR pode induzir hipertrofia excêntrica com melhora da função cardíaca em coração de ratos sadios, e também reduzir a hipertrofia, modulando o sistema renina angiotensina aldosterona (SRAA), em animais hipertensos. Pouco se sabe sobre os efeitos do AR em coração de humanos. Pacientes portadores de acne fazem uso de um tipo de AR que é o 13- cis-AR, também chamado de isotretinoína e por isso possibilitam o estudo do papel do AR em humanos. Estudo prévio mostrou que com 2 meses de uso do 13-cis-AR houve remodelação cardíaca. Entretanto, não se sabe sobre os mecanismos ou se essas alterações são reversíveis. Objetivos: Portanto, os objetivos desse trabalho foram de comparar a avaliação morfofuncional cardíaca e variáveis do SRAA entre pacientes em uso de isotretinoína com um grupo controle. Adicionalmente, avaliar se as alterações são reversíveis em pacientes em uso de isotretinoína. Casuística e Métodos: Foram estudados 35 adolescentes e adultos jovens, com idade entre 14 e 23 anos, do sexo masculino, sendo 20 deles em uso de isotretinoína oral, na dose de 0,5 mg/kg/dia a 0,75 mg/kg/dia, acompanhados no ambulatório de dermatologia do Hospital das Clínicas da Faculdade de Medicina de Botucatu (FMBUNESP), aos 6 meses de tratamento. Os outros 15 pacientes foram convidados na comunidade ou apresentavam acne leve com indicação apenas de tratamento tópico. Foram realizados avaliação morfofuncional e doppler tissular por meio de ecocardiografia transtorácica, dosagens bioquímicas de rotina e dosagens de componentes do SRAA renina, angiotensina I, angiotensina II, aldosterona, angiotensina 1-7 e alamandina. Essas variáveis foram comparadas nos grupos controle e isotretinoína pelo teste t de student ou Mann Whitnney. Os pacientes que receberam isotretinoína foram estudados antes do início do tratamento, com 6 meses de tratamento e 2 meses após o término do tratamento. Esses momentos foram comparados por meio do teste de Anova de 1 via de medidas repetidas. O nível de significância adotado foi de 5%. Resultados: Os pacientes do grupo controle e isotretinoína apresentaram a mesma idade, índice de massa corcoral, pressão arterial e frequência cardíaca. Dosagens bioquímicas habitualmente solicitadas durante o tratamento como enzimas hepáticas, função renal e triglicérides também foram semelhantes entre os grupos. Os dados morfológicos mostraram aumento do diâmetro diastólico do ventrículo esquerdo (DDVE) acompanhado de aumento do débito cardíaco e do fluxo transmitral avaliado por E/E’. Houve aumento do volume do átrio esquerdo (AE), no limite da significância e tendência ao aumento da massa do ventrículo esquerdo (VE) e com espessura relativa da parede semelhante entre os grupos. Sobre o SRAA houve redução da angiotensina II e da renina. Na avaliação ecocardiográfica apenas dos pacientes em uso de isotretinoína observou-se que houve redução do AE e do índice de massa do VE (IMVE) após 2 meses do término do tratamento. Embora não significativo, o comportamento de E/E’ também foi de redução após o tratamento. Discussão: O 13-cis-AR promove remodelação cardíaca, provavelmente induzida por hipervolemia, levando a um padrão de hipertrofia excêntrica com melhora da função. Essas alterações provavelmente levaram a menor ativação do SRAA visto pela redução da renina e angiotensina II. Esse perfil de remodelação e de bloqueio do SRAA é semelhante ao que ocorre no exercício físico. Nesse estudo foi possível apenas avaliar o grupo isotretinoína, quanto às variáveis ecocardiográficas antes, durante e após o tratamento. Observa-se que o término do estimulo com 13-cis-AR reduz algumas variáveis como átrio esquerdo e massa do VE. Portanto, em corações normais de adultos jovens, o AR atenuou o efeito de SRAA e promoveu remodelação cardíaca do tipo excêntrica, com melhora da função, compatível com sobrecarga volêmica e com caráter transitório. / Background: The influence of retinoic acid (RA) in the heart is very relevant, occurring during the embryogenesis, differentiation and cardiac development. Experimental studies shown that RA induces excentric hypertrophy, with improvement of cardiac function in heart of healthy rats. In addition, it was observed that RA regulates renin angiotensin aldosterone system (RAAS), a regulatory system involved in blood pressure, volume homeostasis and cardiac hypertrophy. There is a lack of information about the role of RA on cardiac remodeling in adult humans. Otherwise there are patients with Acne that uses 13- cis-RA, also called isotretinoin, and this population allow the investigation of cardiac remodeling and RA treatment. In fact, previously study shown that the use of 13-cis-RA, for acne, for 2 months induced cardiac remodeling, however, no one knows if these changes are persistent and reversible. Objectives: the objectives of these study is to compare the cardiac morphofunctional evaluation and RASS variables in patients using isotretinoin and in control group. Additionally, evaluate if these changes are reversible in isotretinoin group. Casuistic and Methods: Study1: 35 young men, between 14 to 23 years, 20 in use of 13-cis-RA, in the dose of 0,5 mg/kg/day to 0,75 mg/kg/day, from dermatology clinic of São Paulo State University (FMB-UNESP), at 6 months of treatment. The others 15 patients had mild acne only with topic treatment. Morphofunctional evaluation, tissular Doppler, Biochemical evaluation, dosage of RAAS components were performed. Results were compared in isotretinoin and control group by t student or Mann Whitnney tests. Study 2: Only the isotretinoin group were evaluated before beginning of treatment (initial moment - M0), after 6 months of treatment (final moment - M1) and two months after finishing the medication (M2). This results were compared by One way pared Anova. The statistically significant level was set at 5%. Results: control and isotretinoin group presents similar age, body mass index, blood pressure and heart rate. Biochemical evaluation was also similar. The present study showed that young patients receiving 13-cis-RA for Acne treatment presented left ventricle and atrium chamber enlargement and increase in cardiac output and in mitral flows. There was a trend toward higher ventricular mass with preserved relative wall thickness. RAAS showed decreased in angiotensin II and renin. Considering only patients that received isotretinoin, it was observed that cardiac atrium size and flows returned to baseline 2 months after the end of treatment and cardiac structures such as ventricle mass and thickness reduced. Discussion: 13-cis-RA promotes cardiac remodeling, probably induced by hypervolemia, taking to a pattern of eccentric hypertrophy, with improvement of function. It is possible that hypervolemia or a direct effect of 13-cis-RA, reduces renin and angiotensin II. The remodeling phenotype described is compatible with cardiac remodeling induced by physical activity, marked by hypervolemia, excentric hypertrophy and increased cardiac output. In the isotretinoin group, the end of treatment reduces left atrium size and left ventricle mass. Therefore, in normal hearts of young adults, RA reduces the effect of RAAS and promotes eccentric cardiac remodeling, with improvement of function, compatible with volume overload and with transitory character.

Submitted by ANTONIO BACCARO null (antbaccaro@bol.com.br) on 2017-10-18T15:24:30Z No. of bitstreams: 1 Versão final Tese Doutorado 3 agosto 2017 Final - Antonio Baccaro Resumo ok.pdf: 1139639 bytes, checksum: 4b20e04d1939d61e79ee5c360ae47acc (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-10-23T18:59:29Z (GMT) No. of bitstreams: 1 baccaro_a_dr_bot.pdf: 1139639 bytes, checksum: 4b20e04d1939d61e79ee5c360ae47acc (MD5) / Made available in DSpace on 2017-10-23T18:59:29Z (GMT). No. of bitstreams: 1 baccaro_a_dr_bot.pdf: 1139639 bytes, checksum: 4b20e04d1939d61e79ee5c360ae47acc (MD5) Previous issue date: 2017-08-28 / Introdução: A artrite reumatoide (AR) é uma doença inflamatória crônica que acomete não apenas articulações, mas também outros órgãos, como por exemplo, o coração. A inflamação sistêmica exerce papel fundamental no desenvolvimento do acometimento articular e extra-articular. Dessa forma, existe risco aumentado para doença coronariana em pacientes com AR. É possível acometimento direto do coração desencadeando o processo de remodelação cardíaca, como a hipertrofia e alterações de geometria cardíaca, que podem passar anos sem causar sintomas. Outra característica particular da AR e também relacionada com a inflamação crônica é o fato de apresentarem composição corporal com fenótipo mais voltado para o sobrepeso, mas com a possibilidade de terem massa muscular reduzida. A obesidade, por si, já eleva o risco para acometimento cardíaco, entretanto, pouco se sabe sobre a participação de variáveis da composição corporal e de alguns marcadores inflamatórios na remodelação cardíaca de pacientes com AR. Objetivos: Avaliar se variáveis da composição corporal e inflamação, avaliada por metalopreteaases (MMP-2 e MMP-9), associam-se à remodelação e função cardíaca. Metodologia: Foram estudados 71 pacientes com AR, submetidos a avaliação clínica, antropométrica, da composição corporal por bioimpedância e densitometria de dupla emissão de radiação X, avaliação cardiológica por ecocardiografia transtorácica, avaliação da atividade inflamatória por DAS-28 e dosagem da atividade das metaloproteases. A regressão logística e linear foi realizada para avaliar a associação das variáveis com remodelação ventricular. Essas equações foram ajustadas por fatores que sabidamente influenciam na remodelação cardíaca, como hipertensão, DAS-28, idade, sexo. Resultados: A maioria dos pacientes são do sexo feminino, em média apresentam atividade leve da doença, sobrepeso e alta frequência de hipertensão. Em relação aos diagnósticos nutricionais, 90% apresentam porcentagem de gordura acima do normal, 20% apresentam porcentagem de gordura acima do normal e massa magra menor que P25%, e 14,6% apresentam sarcopenia, a razão entre água intracelular e extracelular sugerem hipervolemia. Ao avaliarmos os pacientes de acordo com a atividade da doença, observa-se que a MMP-9 está mais elevada em Abstract 3 paciente com atividade moderada e os pacientes com doença em atividade leve apresentam maior massa de gordura. O IMC, sarcopenia, porcentagem de gordura acima do normal e massa magra abaixo do P25% não explicaram a remodelação ventricular. A massa magra avaliada pelo DEXA associou-se com maior espessura relativa da parede e massa ventricular, mas a gordura não se associou a esses desfechos. A MMP-9 aumentou em 3,4 vezes o risco para aumento da ERP. Conclusão: A provável associação entre massa magra corporal e massa cardíaca provavelmente se deve a maior massa de água desses pacientes. Os métodos disponíveis não permitem a avaliação da água isolada da massa muscular. A MMP- 9 é um dos marcadores mais estudados nas articulações, mas percebe-se que sua concentração sérica também poderia associar-se a desfechos extracardíacos. / Introduction: Rheumatoid arthritis (RA) is a chronic inflammatory disease that affects not only joints, but also other organs, such as the heart. Systemic inflammation plays a fundamental role in the development of joint and extraarticular involvement. Thus, there is an increased risk for coronary disease in patients with RA. Direct heart involvement can be triggered by the process of cardiac remodeling, such as hypertrophy and changes in cardiac geometry, which can go years without causing symptoms. Another particular feature of AR and also related to chronic inflammation is the fact that they present a body composition with a phenotype more focused on being overweight, but with the possibility of having reduced muscle mass. Obesity, by itself, already raises the risk for cardiac involvement, however, little is known about the participation of body composition variables and some inflammatory markers in the cardiac remodeling of RA patients. Objectives: To evaluate whether body composition and inflammation variables, evaluated by metalloptreteaases (MMP-2 and MMP-9), are associated with remodeling and cardiac function. Methodology: A total of 71 patients with RA underwent clinical, anthropometric evaluation of the body composition by bioimpedance and dual emission X-ray densitometry, cardiac evaluation by transthoracic echocardiography, evaluation of inflammatory activity by DAS-28 and dosage of metalloprotease activity. Logistic and linear regression were performed to evaluate the association of variables with ventricular remodeling. These equations were adjusted by factors known to influence cardiac remodeling, such as hypertension, DAS-28, age, sex. Results: Most of the patients are female, on average they have mild disease activity and are overweight, with a high frequency of hypertension. In relation to nutritional diagnoses, 90% had a percentage of fat above normal, 20% had fat percentage above normal and lean mass lower than P25%, and 14.6% presented sarcopenia, the ratio between intracellular and extracellular water suggest hypervolemia. When evaluating the patients according to the activity of the disease, it is observed that MMP-9 is higher in patients with moderate activity and patients with disease in mild activity have higher fat mass. BMI, sarcopenia, percentage of fat above normal and lean mass below P25% did not explain ventricular remodeling. The lean mass assessed by DEXA was associated with a greater relative thickness of the wall and ventricular mass, but fat was not associated with these outcomes. MMP-9 increased by 3.4 times the risk for increased PRS. Conclusion: The probable association between lean body mass and heart mass is probably due to the greater body mass of these patients. The available methods do not allow the evaluation of water isolated from muscle mass. MMP-9 is one of the most studied markers in the joints, but it is perceived that its serum concentration could also be associated with extracardiac outcomes.

O presente trabalho buscou identificar uma possível relação causa-efeito entre exercício, SRA, remodelamento cardíaco e função autonômica na redução da pressão arterial (PA) induzida pelo treinamento aeróbio (T) iniciado na fase pré-hipertensiva. SHR, com 4 semanas de idade, foram submetidos ao T (55% da capacidade física, 1h/dia, 5x/semana) ou mantidos sedentários (S) por 8 semanas. WKY serviram como controle temporal. Os parâmetros foram avaliados nas semanas 0, 1, 2, 4 e 8. Nossos dados indicam que o treinamento iniciado ainda na fase pré-hipertensiva, protege o coração reduzindo a expressão relativa de receptores AT1 e a hipertrofia cardíaca, reduz a FC basal e aumenta sua variabilidade por facilitar o componente vagal alterando o balanço simpato-vagal ao coração. Estas adaptações contribuem para retardar a instalação, reduzindo substancialmente os níveis pressóricos atingidos na fase crônica da hipertensão arterial. A oposição precoce aos efeitos deletérios da hipertensão pelo treinamento é fundamental para minimizar seus prejuízos estruturais e funcionais. / In the present dissertation, we identified a possible cause-effect relation between exercise training, SRA, cardiac remodeling and autonomic function during the establishment of essential hypertension. 4 weeks-old SHR were submitted to aerobic training (5x/week; 1hour/day; 55% of maximal exercise capacity). Factors were assessed on weeks 0,1,2,4 and 8. Exercise training was able to attenuate increase AP, vascular sympathetic activity, cardiac remodeling and cardiac AT1 protein expression; to intensify decrease HR; to increase HR variance and cardiac vagal activity. Our data indicate that aerobic training, during pre-hypertensive phases, attenuates cardiac remodeling associated with decrease of AP, cardiac AT1 protein expression and autonomic dysfunction in SHR. Premature modulation of maladaptative effects of hypertension induced by aerobic tranining seem to be crucial to minimize long-term deleterious effects in cardiac structure and function.

Orientador: Silméia Garcia Zanati Bazan / Resumo: Fundamento: O arsenal terapêutico da insuficiência cardíaca (IC) consiste em diversas classes de medicamentos, utilização de marcapasso e cardiodesfibriladores implantáveis e reeducação alimentar. E são cada vez mais reconhecidos os benefícios do exercício físico (EF) na sobrevida, na qualidade de vida (QV), na capacidade funcional (CF), na inflamação, na função autonômica, no remodelamento cardíaco reverso e na função endotelial. A hipótese é a de que um programa de EF combinado (EFC), ou seja, EF aeróbico complementado por EF de força é capaz de promover melhora na função cardíaca global, e que esses efeitos estão associados ao aumento da CF e da QV desses pacientes. Objetivos: Verificar o efeito de um programa de EFC sobre as variáveis ecocardiográficas morfológicas e funcionais cardíacas; Avaliar a CF e a QV dos pacientes; Analisar a associação ou correlação entre as variáveis clínicas. Métodos: Ensaio clínico longitudinal, randomizado e controlado, composto por pacientes com IC com fração de ejeção reduzida (ICFER). Foram incluídos 82 voluntários divididos em dois grupos: Grupo Controle (GC n=41): receberam apenas recomendação médica de atividades físicas de rotina; Grupo Intervenção (GI n=41): submetidos a um programa de EFC e supervisionado, composto por exercício aeróbico do tipo caminhada contínua, acrescidos de EF de força, três vezes por semana durante 16 semanas. Ambos os grupos foram submetidos inicialmente e após 16 semanas de protocolo, aos seguintes procedimen... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Background: The therapeutic arsenal of heart failure (HF) consists of several classes of drugs, use of pacemakers and implantable cardiodesfibrillators, and nutritional education. And the benefits of physical exercise (PE) on survival, quality of life (QoL), functional capacity (FC), inflammation, autonomic function, reverse cardiac remodeling and endothelial function are increasingly recognized. The hypothesis is that a combined PE (CPE) program, ie, aerobic PE supplemented by strength PE, is capable of improving overall heart function and that these effects are associated with increased FC and QoL of these patients. Objectives: To verify the effect of a CPE program on cardiac morphological and functional echocardiographic variables; Evaluate the FC and QoL of the patients; Analyze the association or correlation between clinical variables. Methods: Longitudinal randomized controlled trial composed of patients with HF with reduced ejection fraction (HFrEF). Eighty-two volunteers were divided into two groups: Control Group (CG n = 41): received only medical recommendations for routine physical activities; Intervention Group (IG n = 41): undergoing a supervised CPE program, consisting of continuous walking type aerobic exercise, plus strength PE three times a week for 16-weeks. Both groups were initially submitted and after 16 weeks of protocol to the following procedures: 12-minute Cooper walk test, IPAQ and QoL questionnaires (SF36), handgrip test and transthoracic echocardio... (Complete abstract click electronic access below) / Doutor

Orientador: Sergio A.R. de Paiva / Resumo: A deficiência/insuficiência de vitamina D tem aumentado nos últimos anos e tornou-se problema mundial de saúde pública. Além do raquitismo, a deficiência de vitamina D também está associada com maior risco de desenvolver câncer, doenças imunológicas e, inclusive, doenças cardiovasculares. Estes fatores têm incentivado o uso indiscriminado da suplementação de vitamina D na população saudável. Suplementação de vitamina D, em altas doses, promove estresse oxidativo, inflamação, apoptose, altera o metabolismo energético, morfologia e função cardíaca. Adicionalmente, esta suplementação aumenta a concentração sérica de fósforo, que pode estimular a liberação do fator de crescimento de fibroblasto-23 (FGF-23). Esta maior concentração sérica de FGF-23 pode estar associada à remodelação cardíaca. Outros autores sugerem que a ação do FGF-23 no coração ocorre por meio da via de sinalização calcineurina/fator nuclear das células T ativadas (NFAT). Desta maneira, a menor fosfatemia, promovida pelo uso de sevelamer, poderia atenuar as alterações cardíacas provocadas pela suplementação de vitamina D. Assim, o objetivo deste trabalho é verificar se o tratamento com sevelamer diminui a concentração de FGF-23 e, consequentemente, atenua a remodelação cardíaca, decorrente da suplementação de vitamina colecalciferol, em altas doses. Foram utilizados 169 ratos machos da raça Wistar alocados em seis grupos: 1) Grupo controle alimentado com ração padrão (C, n=27); 2) Grupo controle + 3% de sevelame... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Vitamin D deficiency/insufficiency has increased in recent years and has become a worldwide public health problem. In addition to rickets, vitamin D deficiency is also associated with increased risk of developing cancer, immune diseases and even cardiovascular diseases. These factors have encouraged the indiscriminate use of vitamin D supplementation in the healthy population. High-dose of vitamin D supplementation promotes oxidative stress, inflammation, apoptosis, changes in energy metabolism, morphology and cardiac function. In addition, this supplementation increases the serum phosphorus concentration which can stimulate the release of fibroblast growth factor-23 (FGF-23). Higher serum concentration of FGF-23 can be associated with cardiac remodeling. Other authors suggest that the action of FGF-23 in heart occurs through the signaling pathway calcineurin/nuclear factor of activated T cells (NFAT). Thus, decrease in phosphatemia, promoted by the use of sevelamer, can attenuate the cardiac changes promoted by vitamin D supplementation. The aim of this study is to verify whether treatment with sevelamer decreases the concentration of FGF-23 and, consequently, attenuates cardiac remodeling, due to supplementation of cholecalciferol vitamin, in high doses. 169 male Wistar rats were allocated in six groups: 1) Control group fed standard chow (C, n=27); 2) Control group + 3% sevelamer (C+S, n=26); 3) Group supplemented with 3,000 IU cholecalciferol/kg of chow (VitD 3, n=29); 4)... (Complete abstract click electronic access below) / Doutor

La coronaropathie est une cause majeure de mortalité, motivant la recherche de stratégies limitant le remodelage cardiaque ou stimulant la néovascularisation après un infarctus du myocarde (IDM). Ce travail vise à étudier chez la souris adulte le rôle, sur la fonction cardiaque, de gènes régulant l'angiogenèse et le métabolisme cellulaire en modulant leur expression endothéliale en conditions basales ou en post-IDM (après ligature coronaire) : PPARβ/δ, Wt1, Cyp51 et Dnmt2. Les paramètres échocardiographiques ont été mesurés pré et post-IDM, des analyses histochimiques réalisées, et l’expression de gènes cibles comparée selon le génotype. La surexpression de PPARβ/δ stimule l'angiogenèse basale, causant une hypertrophie ventriculaire gauche (VG). En post-IDM, elle induit un remodelage VG pathologique et majore la taille de l'IDM, posant la question des interactions entre endothélium et cardiomyocytes. En post-IDM, l'invalidation de Wt1 limite l'angiogenèse coronaire, majore le remodelage VG et la taille de l'IDM. A l'état basal, l'invalidation de Cyp51 est à l'origine d'une insuffisance cardiaque dilatée, via une perméabilité vasculaire accrue et une activation endothéliale. La modification de la composition membranaire en stérols peut expliquer la dysfonction de l'endothélium, modifiant ses interactions avec les cardiomyocytes. Ainsi, Cyp51 possède un rôle essentiel dans la structure et la fonction cardiaque, ouvrant le champ de son étude en post-IDM. Enfin, l'expression de Dnmt2 est indispensable pour limiter l'hypertrophie cardiaque, via le contrôle de l'activité de l'ARN polymérase II par la méthylation de l’ARN non codant Rn7sk. / Coronary heart disease is a major cause of mortality, explaining the increasing interest in therapeutics targeting cardiac remodeling and neovascularization after myocardial infarction (MI). Using endothelial expression modulation in adult mice in basal or post-MI conditions (after coronary artery ligation), this work studied several genes involved in angiogenesis and cardiac metabolism, PPARβ/δ, Wt1, Cyp51 and Dnmt2, and their role in cardiac function. Echocardiographic structural and functional parameters were measured before and after MI, histochemistry analyses performed, and target genes expression compared between different genotypes. PPARβ/δ basal overexpression resulted in an increased angiogenesis and cardiac hypertrophy. After MI, it caused MI expansion through increased cardiac remodelling. This discrepancy raises the issue of communication between endothelial cells and cardiomyocytes. Endothelial Wt1 expression is essential for cardiac repair after MI : deletion was responsible for neovascularization impairment, poorer cardiac remodeling and MI enlargement. Endothelial Cyp51 expression is necessary for basal cardiac structure and function. After Cyp51 deletion, membrane and cell junction disorganization caused increased vascular permeability and endothelium activation, resulting in dilated cardiomyopathy. The accumulation of toxic oxysterols or lack of cholesterol might account for endothelial dysfunction, through abnormal endothelial cells to cardiomyocytes signalling. Dnmt2 deletion caused cardiac hypertrophy. through methylation of non-coding RNA Rn7sk and control of RNA polymerase II activity.

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Le remodelage cardiaque est un élément central dans le développement et la progression de l'insuffisance cardiaque, une cause majeure de morbi/mortalité dans le monde. Il est défini par les changements structurels, métaboliques et fonctionnels du ventricule gauche qui se manifestent cliniquement par des modifications de taille et de forme du cœur dans diverses situations pathologiques telles que l'hypertension, l'infarctus du myocarde ou l'obésité. Il s'agit donc d'un procédé complexe et dynamique qui implique une hypertrophie des cardiomyocytes, une production massive de radicaux libres (ROS) et une perte importante de cardiomyocytes par apoptose/nécrose. Cette perte cellulaire induit l'activation des fibroblastes cardiaques et le développement progressif d'une fibrose interstitielle conduisant à l'insuffisance cardiaque. Mon projet de thèse est centré sur l'étude du rôle de la kinase PIKfyve dans le remodelage ventriculaire et l'insuffisance cardiaque. PIKfyve est une lipide kinase conservée au cours de l'évolution qui régule de nombreuses fonctions cellulaires fondamentales. Par des approches in vitro et in vivo sur des modèles murins d'insuffisance cardiaque, mes travaux de thèse identifient PIKfyve et son produit le phosphatidylinositol 5-phosphate comme acteurs clés de l'altération du statut cardiométabolique et de l'intégrité mitochondriale en conditions pathologiques. L'inhibition pharmacologique et épigénétique de l'enzyme préserve l'intégrité mitochondriale, réduit le stress oxydant, l'apoptose cardiomyocytaire, et culmine par l'amélioration des fonctions cardiaques dans un modèle d'insuffisance cardiaque liée à l'obésité. De plus, mes travaux identifient un nouveau mécanisme de régulation de la réponse au stress cellulaires par PIKfyve qui implique une voie de la désacétylase mitochondriale SIRT3.[...] / Cardiac remodeling is a key process in the development and the progression of heart failure, one of the leading causes of morbi/mortality in modern societies. It is defined as a combination of structural, metabolic and functional modifications that clinically manifest as changes in size and shape of the heart, and under the influence of risk factors such as hypertension, myocardial infarction and obesity. Cardiac remodeling is a complex and dynamic process characterized by cardiomyocyte hypertrophy, excessive reactive oxygen species (ROS) generation leading to a massive loss of cardiomyocytes by apoptotic/necrotic cell death. Altogether, these events trigger the differentiation of cardiac fibroblasts into myofibroblasts and the progressive development of interstitial fibrosis leading to cardiac dysfunction. My thesis work focuses on the role of the lipid kinase PIKfyve in cardiac remodeling and heart failure. PIKfyve is the product of an evolutionary conserved single-copy gene and is known to regulate pleiotropic cellular functions. Combining in vitro and in vivo studies in mouse models of cardiac remodeling, my work identifies PIKfyve and its product phosphatidylinositol 5-phosphate as master regulators of the cardiometabolic status and mitochondrial integrity under pathological conditions. Pharmacological or epigenetic inhibition of the enzyme preserves mitochondrial integrity, reduces oxidative stress, myocyte apoptotic death and culminates with improved cardiac function in a mouse model of obesity induced heart failure. These effects are mediated by the mitochondrial deacetylase SIRT3. My work also demonstrates that PIKfyve is a necessary factor in the differentiation of cardiac fibroblasts into myofibroblasts during cardiac remodeling, regulating the TGF-beta/Smad pathway. Altogether, my thesis work unravels a novel role for PIKfyve in myocardial remodeling and paves the way for alternative therapies as a new molecular target for the treatment of cardiometabolic and fibrotic diseases.

Dilated (DCM) and ischemic cardiomyopathies (ICM) are associated with cardiac remodeling, where the ubiquitin–proteasome system (UPS) holds a central role. Little is known about the UPS and its alterations in patients suffering from DCM or ICM. The aim of this study is to characterize the UPS activity in human heart tissue from cardiomyopathy patients. Myocardial tissue from ICM (n = 23), DCM (n = 28), and control (n = 14) patients were used to quantify ubiquitinylated proteins, E3-ubiquitin-ligases muscle-atrophy-F-box (MAFbx)/atrogin-1, muscle-RING-finger-1 (MuRF1), and eukaryotic-translation-initiation-factor-4E (eIF4E), by Western blot. Furthermore, the proteasomal chymotrypsin-like and trypsin-like peptidase activities were determined fluorometrically. Enzyme activity of NAD(P)H oxidase was assessed as an index of reactive oxygen species production. The chymotrypsin- (p = 0.71) and caspase-like proteasomal activity (p = 0.93) was similar between the groups. Trypsin-like proteasomal activity was lower in ICM (0.78 ± 0.11 µU/mg) compared to DCM (1.06 ± 0.08 µU/mg) and control (1.00 ± 0.06 µU/mg; p = 0.06) samples. Decreased ubiquitin expression in both cardiomyopathy groups (ICM vs. control: p < 0.001; DCM vs. control: p < 0.001), as well as less ubiquitin-positive deposits in ICM-damaged tissue (ICM: 4.19% ± 0.60%, control: 6.28% ± 0.40%, p = 0.022), were detected. E3-ligase MuRF1 protein expression (p = 0.62), NADPH-oxidase activity (p = 0.63), and AIF-positive cells (p = 0.50). Statistical trends were detected for reduced MAFbx protein expression in the DCM-group (p = 0.07). Different levels of UPS components, E3 ligases, and UPS activation markers were observed in myocardial tissue from patients affected by DCM and ICM, suggesting differential involvement of the UPS in the underlying pathologies.

Il y a 4 isoforme de p38 : α, β, δ, and γ. MK5, à l'origine identifié comme étant un régulateur de PRAK (Regulated/Activated Protein Kinase), est maintenant connu pour être activée par la protéine kinase p38 (qui est un mitogène activé par la protéine kinase, MAPK). Cette dernière est impliquée dans les mécanismes de fibrose et d'apoptose pendant l'hypertrophie cardiaque. De plus, MK5 est également activée par les MAPKs atypiques; ERK3 et ERK4. Bien qu’elles soient fortement exprimées dans le coeur, le rôle physiologique de MK5 et ERK3 demeure inconnu. Par conséquent, nous avons étudié l'effet de la constriction aortique transversale (TAC) – induisant un surcharge chronique de pression chez les souris hétèrozygotes knockout pour MK5 (MK5+/-) ou ERK3 (ERK3+/-) et pour leurs types sauvages (MK5+/+ et ERK3+/+). Deux sem post-TAC; le ratio de poids du coeur/poids corporel a été augmenté chez les 2 souris MK5+/- et MK5+/+. L'échocardiographie de la trans-thoracique démontre que la surcharge de pression a altéré la fonction diastolique du ventricule gauche chez MK5+/+, mais pas chez la souris MK5+/-. De plus, nous avons observé moins de dépôt de collagène, évalué par une coloration au trichrome de Masson, 2 et 3 sem post-TAC chez les souris MK5+/-. Parallèlement, le niveau de l’ARNm de collagène type1 alpha-1 a été significativement diminué dans les coeurs des souris MK5+/-, 2 et 3 sem post-TAC. De même, ERK3, mais pas ERK5 ni p38α, co-IP avec MK5 dans les 2 modèles des coeurs TAC; aigus ou chroniques. En revanche, l’ajout exogénique de GST-MK5 a abaissé ERK4 et p38α, mais pas ERK3 dans les lysâtes de coeur de souris. Par contre, GST-ERK3 et GST-p38α ne démontrent aucune co-IP avec MK5. Ces données suggèrent que dans le coeur seul ERK3, et non ERK4 ou p38α, est capable d’interagir avec, et réguler MK5. A niveau physiologique MK5 interagit entièrement avec ERK3 et par conséquent MK5 n’est pas disponible pour lier les protéines exogéniques. Les souris hétérozygotes pour ERK3 (ERK3+/-) ont également démontré une réduction ou une absence de collagène et une faible expression d’ARNm du collagène type1 alpha1, 3 sem post-TAC. Ces résultats démontrent un important rôle pro-fibrotique de la signalisation MK5-ERK3 pendant une surcharge chronique de pression.Nous avons également démontré 5 variant d'épissage de (MK5.1-5), y compris la forme originale (MK5.1). MK5.2 et MK5.5 subissent une délétion de 6 paires de base dans l’exon 12 : MK5.3 manque l'exon 12 : MK5.4 et MK5.5 manquent les exons 2-6. L'expression des ARNm des différents variant d'épissage a été vérifiée par PCR en temps réel (qPCR). Bien que l’expression est ubiquitaire, l'abondance relative de chaque variant était tissu-spécifique (coeur, rein, pancréas, muscle squelettique, poumon, foie, et cerveau). En plus, l'abondance relative des variant d’épissage varie pendant la surcharge de pression et le développement postnatal du coeur. En outre, l'immunofluorescence a indiqué que MK5.1-5.3 se localise au noyau alors que MK5.4-5.5 est situé au niveau cytoplasmic dans les cellules HEK 293 non stimulées. Suite à une stimulation avec l'anisomycin, un activateur de p38 MAPK, MK5.1-5.3 se translocalise du noyau au cytoplasme alors qu’une petite fraction de MK5.4-5.5 translocalise vers le noyau. Ces variant d'épissage peuvent diversifier la signalisation de MK5-ERK3 dans coeur, mais leur rôle exact oblige des recherches supplémentaires. Excepté l’isoforme δ, toutes les isoformes de p38 sont exprimées dans le coeur et la forme α est considérée comme étant l'isoforme dominante. L’analyse par qPCR et immunobuvardage de type western ont démontré que p38α et p38γ sont les deux isoformes prédominantes alors que p38β et p38δ sont exprimées aux mêmes niveaux dans le coeur de rat adulte. L'immunofluorescence a démontré que p38α et p38γ se trouvent dans le cytoplasme et le noyau. Cependant, suite à la surcharge par TAC, p38γ s'est accumulé dans noyau tandis que la distribution de p38α est demeurée inchangée. Ainsi, l'abondance de p38γ et sa translocalisation nucléaire suite à la surcharge de pression indique un rôle potentiel dans l'expression génique pendant le remodelage cardiaque. En conclusion, nous avons mis en évidence pour la première fois un rôle pro-fibrotique pour la signalisation MK5-ERK3 pendant une surcharge chronique de pression. D'ailleurs, les niveaux comparables d'expression de p38γ avec p38α, et la localisation différentielle de p38γ pendant la surcharge aiguë ou chronique de pression suggèrent différents rôles possibles pour ces isoformes pendant le remodelage hypertrophique cardiaque. / There are 4 isoforms of p38 MAP kinase: α, β, γ, and δ. p38 signaling has been implicated in fibrosis and apoptosis during cardiac hypertrophy. MK5, originally identified as a p38 Regulated/Activated Protein Kinase (PRAK), is known to be downstream of p38 mitogen activated protein kinase (MAPK). Although highly expressed in the heart, the physiological roles of MK5 remain unknown. To determine if MK5 plays a role in mediating detrimental effects downstream of p38, we studied the effect of transverse aortic constriction (TAC)-induced chronic pressure overload in mice heterozygous for a knockout of MK5 (MK5+/-). Moreover, as MK5 is also activated by the atypical MAPKs, ERK3 and ERK4, the effects of TAC were also studied in ERK3+/- mice. Wild-type (MK5+/+; ERK3+/+) littermates were used as controls. Two wks post-TAC, heart weight/body weight ratios were significantly and similarly increased in both MK5+/- and MK5+/+ hearts. Trans-thoracic echocardiography revealed that pressure overload impaired left ventricular diastolic function in MK5+/+, but not in MK5+/- hearts. In addition, less collagen deposition, assessed by Masson trichrome staining, was observed in MK5+/- hearts 2 and 3 wks post-TAC. Furthermore, TAC-induced increases in collagen alpha1 type1 mRNA levels were significantly lower in MK5+/- hearts at both 2 and 3 wks post-TAC. Immunoprecipitation of MK5 resulted in co-immunoprecipitation of ERK3 but not ERK4 or p38α in either acute or chronic sham-operated and TAC hearts. In contrast, exogenous GST-MK5 pulled down endogenous ERK4 and p38α, but not ERK3, from mouse heart lysates. Neither exogenous GST-ERK3 nor GST-p38α pulled down MK5. These results suggest that MK5 associates with, and is regulated by ERK3, but not ERK4 or p38α in heart. At physiological expressional levels, all MK5 was bound to ERK3 and hence not available to bind exogenous protein. Along similar lines, mice heterozygous for an ERK3 knockout (ERK3+/-) also showed reduced or absent collagen deposition and lower collagen alpha1 type1 mRNA levels 3 wks post-TAC. This data suggests an important pro-fibrotic role of MK5-ERK3 signaling during chronic pressure overload.We also demonstrated the existence of 5 splice variants of (MK5.1-5), including the originally published form (MK5.1). MK5.2 and MK5.5 had a 6 base pair deletion in exon 12: MK5.3 lacked exon 12: and MK5.4 and MK5.5 lacked exons 2-6. Subsequently, expression of the splice variants at the mRNA level was quantified by real time qPCR. Although ubiquitously expressed, the relative abundance of each variant was tissue-specific (heart, kidney, pancreas, skeletal muscle, lung, liver, and brain). Additionally, the relative abundance of MK5 splice variants changed in the heart during pressure overload and post-natal development. Furthermore, immunofluorescence revealed MK5.1-5.3 localized to the nucleus and MK5.4-5.5 to the cytoplasm in unstimulated HEK 293 cells. Upon stimulation with anisomycin, which activates p38 MAPK, MK5.1-5.3 translocated from the nucleus to the cytoplasm and small amounts of MK5.4-5.5 relocated to the nucleus. These splice variants may further diversify MK5-ERK3 signaling in the heart, but their exact role awaits further investigation. With the exception of p38δ, all p38 isoforms are expressed in the heart and α is considered to be the prominent isoform in this tissue. qPCR and western blot analysis revealed p38α and p38γ to be the predominant isoforms and p38β and p38δ are expressed at comparable levels in the adult heart. Confocal immunofluorescence studies revealed p38α and p38γ in both the cytoplasm and nucleus. However, in response to TAC, p38γ accumulated in the nucleus whereas the distribution of p38α remained unaffected. The high abundance of p38γ and its nuclear accumulation during chronic pressure overload suggest that this isoform may play a role in gene expression during pathological cardiac remodeling. In conclusion, we have shown for the first time a pro-fibrotic role for MK5-ERK3 signaling during chronic pressure overload. Moreover, comparable expression levels of p38γ with p38α, and differential localization of p38γ during acute or chronic pressure overload, suggest these isoforms play different roles during cardiac remodeling.