L’aldostérone et le Récepteur Minéralocorticoïde (MR) participent au contrôle de la balance hydrosodée et de la pression artérielle. Les altérations de l’expression du MR ou de la signalisation minéralocorticoïde sont associées à de nombreuses pathologies chez l’Homme. Dans ce travail, nous avons démontré, le rôle majeur de protéines de liaison à l’ARN, Tis11b et HuR, dans le contrôle post-transcriptionnel de l’expression du MR en réponse aux variations de tonicité extracellulaire dans un modèle de cellules principales rénales et chez la souris. L’hypertonicité (500 mOsmol/L) induit l’expression de la protéine Tis11b, qui lie la région 3’-non traduite du transcrit MR afin d’accélérer sa dégradation, diminuant ainsi l’expression rénale de la protéine MR et de la signalisation minéralocorticoïde. A l’opposé, l’hypotonicité (150 mOsmol/L) stimule la translocation nucléo-cytoplasmique de HuR, qui stabilise le transcrit MR, augmentant ainsi l’expression du MR et la sensibilité rénale à l’aldostérone. De plus, HuR est responsable de l’édition d’un nouveau variant d’épissage du MR, le variant MR Δ6, obtenu par l’exclusion de l’exon 6.Ce variant d’épissage exerce un effet dominant négatif sur la signalisation minéralocorticoïde. Enfin, l’identification de microARN modulés par l’hypertonicité suggère leur rôle potentiel dans le contrôle de la signalisation minéralocorticoïde rénale. La caractérisation de ces mécanismes inédits modulant l’action du MR améliore notre compréhension de la physiopathologie de la signalisation minéralocorticoïde, et pourrait aboutir, à terme, à de nouvelles stratégies thérapeutiques. / Aldosterone and the Mineralocorticoid Receptor (MR) participate to the control of salt and water balance and the arterial pressure. Alteration of renal MR expression or mineralocorticoid signaling pathway contributes to the development of numerous human disorders. In this work, we have demonstrated the major role played by the RNA-Binding Proteins, Tis11b and HuR, in the control of MR expression in response to variations of extracellular tonicity in a model of principal tubular cells and in vivo. Hypertonicity (500 mOsmol/L) increases the expression ofTis11b, which binds the 3’-untranslated region of MR transcript and accelerates the degradation of MR transcript, leading to the reduction of the mineralocorticoid signaling. Conversely, hypotonicity (150 mOsmol/L) stimulates nuclear-cytoplasmic shuttling of HuR protein, which stabilizes MR transcript increasing its expression and renal sensitivity to aldosterone action. Furthermore, HuR participates to the editing of the novel MR Δ6 splice variant, which lacks exon 6, and exerts a dominant negative effect on mineralocorticoid signaling. Finally, we have provided evidence that hypertonicity modulates expression of microRNA, which may control mineralocorticoid signaling pathway. Characterization of these original mechanisms modulating MR action is pivotal for a better understanding of mineralocorticoid-related pathophysiology, and should ultimately lead to the development of new therapeutic strategies.

Les antagonistes des récepteurs aux minéralocorticoïdes (MR) appartiennent à l'arsenal thérapeutique pour le traitement de diverses maladies cardiovasculaires, mais les mécanismes conférant leurs effets bénéfiques sont encore mal compris. Une partie de ces effets peuvent être liée à la régulation de l'expression du canal Ca2+ de type L Cav1.2, largement impliqué dans l'insuffisance cardiaque et l'hypertension. Nous montrons que MR fonctionne comme un facteur de transcription transformant le signal de l'aldostérone dans l'utilisation du 'cardiaque' promoteur alternatif P1, dirigeant l'expression du long N-terminal transcrit (Cav1.2-LNT. L'aldostérone augmente de façon concentration- et de temps dépendente l'expression de Cav1.2-LNT dans les cardiomyocytes en raison de l'activation du promoteur P1, par interactions des MR avec des séquences spécifiques de l'ADN sur le promoter P1. Ce mécanisme de cis-régulation induit l'activation de promoteur P1 dans les cellules vasculaires conduisant à une nouvelle signature moléculaire de Cav1.2-LNT associé à une sensibilité réduite aux bloqueurs des canaux Ca2+. Ces résultats révèlent Cav1.2-LNT comme une cible minéralocorticoïde spécifique qui pourrait influencer sur l'éfficacité thérapeutique dans les maladies cardiovasculaires. / The mineralocorticoid receptor (MR) antagonists belong to the current therapeutic armamentarium for the management of cardiovascular diseases, but the mechanisms conferring their beneficial effects are still poorly understood. Part of these MR effects might be related to the L-type Cav1.2 Ca2+ channel expression regulation, critically involved in heart failure and hypertension. Here, we show that MR acts as a transcription factor triggering aldosterone signal into specific alternative 'cardiac' P1-promoter usage, given rise to long (Cav1.2-LNT) N-terminal transcripts. Aldosterone increases Cav1.2-LNT expression in cardiomyocytes in a time- and dose-dependent manner due to MR-dependent P1-promoter activity, through specific DNA sequence-MR interactions. This cis-regulatory mechanism induced a MR-dependent P1-promoter switch in vascular cells leading to a new Cav1.2-LNT molecular signature with reduced Ca2+ channel blocker sensitivity. These findings uncover Cav1.2-LNT as a specific mineralocorticoid target that might influence the therapeutic outcome of cardiovascular diseases.

Hippocampal mineralocorticoid receptor mRNA expression was increased in male hamsters exposed to 18 days of short photoperiod relative to animals maintained under long day illumination (p < 0.05). Short day hamsters were also characterized by increased weight gain, and heavier adrenal glands (p < 0.05). The larger adrenals showed selective increases in the widths of the zonae reticularis and glomerulosa (p < 0.001). Incidences of torpor and reduced body temperature were observed in the short day animals. No changes were found in reproductive organ weights, systolic blood pressure, open-field behavior, or stress levels of plasma corticosteroids. We conclude that the hamster brain-adrenal axis responds rapidly to changes in photoperiod, raising the possibility that this axis is a primary mediator of shortened photoperiod responses.

INTRODUCTION : L’insuffisance cardiaque congestive (ICC) induit remodelage pulmonaire et dysfonction ventriculaire droite (VD) qui contribuent de façon importante à la morbidité/mortalité. Malgré l’efficacité prouvée, l’antagonisme des récepteurs minéralocorticoïdes est sous-utilisé en ICC et ses mécanismes d’actions demeurent incompris. Nous avons évalué si l’Aldostérone contribue au remodelage pulmonaire et à la dysfonction VD en stimulant la prolifération des myofibroblastes (MYFs) pulmonaires. MÉTHODE ET RÉSULTATS : L’étude a été réalisée chez des rats avec infarctus du myocarde (IM) de taille modérée à grande permettant le développement de l’ICC. Deux semaines après l’IM, les rats ont été traités avec 100mg/kg/jour d’Aldactone ou non, pendant trois semaines et comparé à un groupe témoin (N=21;24;8). Comparativement au groupe témoin, les rats IM ont développé une ICC caractérisée par une réduction de la fraction de raccourcissement du VG (53±1%vs.16±2%, moyenne±ESM, P<0.0001), une hypertension pulmonaire (PSVD:27±1vs.40±3mmHg, P<0.01) et une hypertrophie VD (VD/(VG+Septum):24±1%vs.38±3%, P<0.05). L’Aldactone n’a eu aucun effet sur ces paramètres. Les rats IM ont développé un syndrome pulmonaire caractérisé par un abaissement de la courbe respiratoire pression-volume, un remodelage structurel pulmonaire avec doublement du poids poumon sec (P<0.01) et de la fibrose pulmonaire avec augmentation du taux de collagène dans les poumons (P<0.05). L’Aldactone n’a pas restauré la fonction pulmonaire. Enfin, les MYFs pulmonaires isolés n’ont pas proliféré avec l’exposition de 48h aux deux traitements d’Aldostérone (10-7M, 10-6M). CONCLUSION : L’Aldostérone ne contribue pas au remodelage pulmonaire et à la dysfonction VD associés à l’ICC. D’autres mécanismes d’actions sont responsables des effets bénéfiques de l’Aldactone. / BACKGROUND: Congestive heart failure (CHF) can induce pulmonary remodeling and RV dysfunction, which importantly contribute to morbidity and mortality. Despite proven efficacy, antagonism of mineralocorticoid receptors is underused in CHF and the mechanisms of its benefits still debated. We hypothesized that Aldosterone contributes to pulmonary remodeling and RV dysfunction by stimulating lung myofibroblasts (MYFs) proliferation. METHODS AND RESULTS: We studied rats with moderate to large myocardial infarcts (MI) to allow CHF development. Two weeks after MI, rats were treated with Aldactone 100mg/kg/day (N=21) or untreated (N=24) for three weeks and compared to a sham group (N=8). Five weeks after MI, infarct size was similar in the two MI groups, both by ultrasound and pathologic measures. Compared to sham, the MI-untreated group developed CHF with reduced LV fractional shortening (53±1%vs.16±2%; mean±SEM, P<0.0001), pulmonary hypertension (RVSP:27±1vs.40±3mmHg, P<0.01) and RV hypertrophy (RV/(LV+septum):24±1%vs.38±3%, P<0.05). Aldactone treatment had no effect on these parameters and did not improve LV or RV performance. CHF induced a restrictive respiratory syndrome characterized by a downward shift of the respiratory pressure-volume loop, important lung remodeling with nearly doubling of dry lung weight (P<0.01) and evidence of lung fibrosis demonstrated by histological lung collagen fractional area (P<0.05). The Aldactone therapy could not restore pulmonary function. Finally, isolated lung MYFs did not proliferate after 48hr exposure to aldosterone (10-7M and 10-6M). CONCLUSION: Aldosterone does not contribute to pulmonary remodeling and RV dysfunction associated with CHF. Other mechanisms of action must be responsible for the beneficial effects of Aldactone in CHF.

This thesis examines the influence of stress on the activity of hippocampal CA1 area. The main task was to determine whether the stress load affects the changes of the local metabolism of glucocorticoids, and whether the levels of corticosteroid receptors in the CA1 hippocampus are modulated in response to stress. In order to answer these questions, the experiments were carried out using three different rat strains - Fisher, Lewis and Wistar which differ in their activities of hypothalamic-pituitary-adrenal axis. Our results demonstrate that stress has no effect on expression of MR mRNA. Conversely, stress reduces the levels of GR mRNA in CA1 area of the dorsal hippocampus. Moreover, we confirmed that the Lewis and Wistar rats didn't change metabolism of glucocorticoids after stress response. By the Fisher rats increased levels of 11β-HSD1 mRNA expression and therefore increased the metabolism of corticosterone.

INTRODUCTION : L’insuffisance cardiaque congestive (ICC) induit remodelage pulmonaire et dysfonction ventriculaire droite (VD) qui contribuent de façon importante à la morbidité/mortalité. Malgré l’efficacité prouvée, l’antagonisme des récepteurs minéralocorticoïdes est sous-utilisé en ICC et ses mécanismes d’actions demeurent incompris. Nous avons évalué si l’Aldostérone contribue au remodelage pulmonaire et à la dysfonction VD en stimulant la prolifération des myofibroblastes (MYFs) pulmonaires. MÉTHODE ET RÉSULTATS : L’étude a été réalisée chez des rats avec infarctus du myocarde (IM) de taille modérée à grande permettant le développement de l’ICC. Deux semaines après l’IM, les rats ont été traités avec 100mg/kg/jour d’Aldactone ou non, pendant trois semaines et comparé à un groupe témoin (N=21;24;8). Comparativement au groupe témoin, les rats IM ont développé une ICC caractérisée par une réduction de la fraction de raccourcissement du VG (53±1%vs.16±2%, moyenne±ESM, P<0.0001), une hypertension pulmonaire (PSVD:27±1vs.40±3mmHg, P<0.01) et une hypertrophie VD (VD/(VG+Septum):24±1%vs.38±3%, P<0.05). L’Aldactone n’a eu aucun effet sur ces paramètres. Les rats IM ont développé un syndrome pulmonaire caractérisé par un abaissement de la courbe respiratoire pression-volume, un remodelage structurel pulmonaire avec doublement du poids poumon sec (P<0.01) et de la fibrose pulmonaire avec augmentation du taux de collagène dans les poumons (P<0.05). L’Aldactone n’a pas restauré la fonction pulmonaire. Enfin, les MYFs pulmonaires isolés n’ont pas proliféré avec l’exposition de 48h aux deux traitements d’Aldostérone (10-7M, 10-6M). CONCLUSION : L’Aldostérone ne contribue pas au remodelage pulmonaire et à la dysfonction VD associés à l’ICC. D’autres mécanismes d’actions sont responsables des effets bénéfiques de l’Aldactone. / BACKGROUND: Congestive heart failure (CHF) can induce pulmonary remodeling and RV dysfunction, which importantly contribute to morbidity and mortality. Despite proven efficacy, antagonism of mineralocorticoid receptors is underused in CHF and the mechanisms of its benefits still debated. We hypothesized that Aldosterone contributes to pulmonary remodeling and RV dysfunction by stimulating lung myofibroblasts (MYFs) proliferation. METHODS AND RESULTS: We studied rats with moderate to large myocardial infarcts (MI) to allow CHF development. Two weeks after MI, rats were treated with Aldactone 100mg/kg/day (N=21) or untreated (N=24) for three weeks and compared to a sham group (N=8). Five weeks after MI, infarct size was similar in the two MI groups, both by ultrasound and pathologic measures. Compared to sham, the MI-untreated group developed CHF with reduced LV fractional shortening (53±1%vs.16±2%; mean±SEM, P<0.0001), pulmonary hypertension (RVSP:27±1vs.40±3mmHg, P<0.01) and RV hypertrophy (RV/(LV+septum):24±1%vs.38±3%, P<0.05). Aldactone treatment had no effect on these parameters and did not improve LV or RV performance. CHF induced a restrictive respiratory syndrome characterized by a downward shift of the respiratory pressure-volume loop, important lung remodeling with nearly doubling of dry lung weight (P<0.01) and evidence of lung fibrosis demonstrated by histological lung collagen fractional area (P<0.05). The Aldactone therapy could not restore pulmonary function. Finally, isolated lung MYFs did not proliferate after 48hr exposure to aldosterone (10-7M and 10-6M). CONCLUSION: Aldosterone does not contribute to pulmonary remodeling and RV dysfunction associated with CHF. Other mechanisms of action must be responsible for the beneficial effects of Aldactone in CHF.

Made available in DSpace on 2016-06-02T19:22:47Z (GMT). No. of bitstreams: 1 DissRBD.pdf: 921826 bytes, checksum: 40bd9588528375b232a2fdf78d110ff9 (MD5) Previous issue date: 2006-08-24 / The hypothesis of a synergy between two hormones responsible for sodium conservation, aldosterone and angiotensin II (ANG II), explains the expression of a characteristic of sodium appetite, hypertonic NaCl intake, in a hypovolemic animal. Hypertonic NaCl intake can be induced in normovolemic rats that received a combined treatment of mineralocorticoid and ANG II at individual doses not sufficient to induce sodium intake (paradigmatic synergy test). Considering the motivation to specific sodium intake another characteristic of sodium appetite, the objective of the present dissertation was to find out a role for the interaction between mineralocorticoid and ANG II on the specificity of sodium appetite. Sprague-Dawley Holtzman rats (&#8773; 300 g b.w.) were housed with access to water and one or more palatable (0.01 M KCl, 0.05 mM CaCl2, 0.15 M NaHCO3, 0.15 M NaCl) or hypertonic (0.50 M NaCl) mineral solutions for ingestion. In two-bottle tests, a bottle contained water and another bottle contained either 0.01 M KCl, 0.15 M NaHCO3, 0.15 M NaCl or 0.50 M NaCl. In five-bottle tests, a bottle contained water and each one of the remaining four bottles contained either 0.01 M KCl, 0.05 mM CaCl2, 0.15 M NaHCO3 or 0.15 M NaCl, respectively. In sodium depletion tests, intact rats received each a 10 mg sc. injection of furosemide or vehicle followed by 24 h access to sodium deficient food and water. Then, food was removed and mineral solutions and water were offered for recording their intake (sodium appetite test). In the paradigmatic synergy test, the animals received daily single sc injection of 2.5 mg of deoxycorticosterone acetate (DOCA) or sunflower oil (vehicle) for three days and a left lateral cerebroventricular injection of 50 ng of ANG II four hours after the last DOCA or oil injection. Fluid intake record began immediately after ANG II injection and food removal. The daily intake record showed no preference for any solution or water when animals had access to five bottles. Sodium depletion induced a preferential sodium intake, with higher NaCl than NaHCO3 intake, in either two- or five-bottle sodium appetite tests. DOCA alone enhanced the daily 0.15 M NaCl and NaHCO3 intake, but did not alter KCl or 0.50 M NaCl intake in two-bottle tests. In the paradigmatic tests with normovolemic animals, ANG II combined to oil induced the ingestion of all three palatable mineral solutions (KCl, NaHCO3, NaCl) and water, in two-bottle tests, and preference for NaHCO3 in five-bottle tests. DOCA pretreatment enhanced only sodium solution intake, particularly NaCl intake, induced by ANG II in two-bottle tests (0.15 M NaCl: DOCA/ANG II = 24.5 ± 6.7 ml/120 min. vs. OIL/ANG II = 9.2 ± 1.8 ml/120 min.; 0.15 M NaHCO3: DOCA/ANG II = 17.0 ± 1.8 ml/120 min. vs. OIL/ANG II = 14.6 ± 2.1 ml/120 min.; 0.01 M KCl: DOCA/ANG II = 9.8 ± 1.9 ml/120 min. vs. 11.9 ± 1.2 ml/120 min.), and enhanced by 80 % the total sodium solution intake in the beginning of the five-bottle test. The combined effect of DOCA with ANG II on the induction of 0.50 M NaCl intake in a two-bottle test was replicated in our animals. The results from the paradigmatic synergy test are coherent with results from sodium appetite tests, suggesting that the mineralocorticoid may turn the effect of ANG II on mineral intake more selective to sodium intake. Thus, the combined ANG II and mineralocorticoid action could contribute to the expression of two characteristics of sodium appetite, not only the acceptance of hypertonic sodium solutions, but also the selective sodium intake. / A hipótese do sinergismo entre dois hormônios responsáveis pela conservação de sódio, a aldosterona e a ANG II, explica uma característica do apetite ao sódio, a ingestão de NaCl hipertônico em um animal hipovolêmico. Ingestão de NaCl hipertônico pode ser induzida em ratos normovolêmicos que receberam um tratamento combinado de mineralocorticóide e ANG II, em doses individuais insuficientes para induzir a ingestão de sódio (teste paradigmático do sinergismo). Sendo a motivação para uma ingestão específica de sódio uma outra característica do apetite ao sódio, o objetivo desta dissertação foi o de procurar um papel para a interação entre mineralocorticóide e ANG II na especificidade do apetite ao sódio. Foram utilizados ratos Sprague-Dawley Holtzman (&#8773; 300 g p.c.) ambientados com livre acesso a bebedouros com água e uma ou mais soluções minerais palatáveis (KCl 0,01 M, CaCl2 0,05 mM, NaHCO3 0,15 M, NaCl 0,15 M) ou hipertônica (NaCl 0,50 M). Em testes de dois bebedouros, um dos bebedouros continha água e o outro, solução de KCl 0,01 M, NaHCO3 0,15 M, NaCl 0,15 M ou NaCl 0,50 M. Em testes de cinco bebedouros, um dos bebedouros continha água e cada um dos demais uma solução de KCl 0,01 M, CaCl2 0,05 mM, NaHCO3 0,15 M ou NaCl 0,15 M. Testes com dois ou cinco bebedouros foram empregados em animais depletados de sódio e no teste paradigmático do sinergismo. Nos testes de depleção de sódio, os animais receberam injeção sc de 10 mg de furosemida ou veículo, seguida de acesso a uma dieta hipossódica e água por vinte e quatro horas. Em seguida, o alimento foi removido e foram oferecidas soluções minerais para registro da ingestão das mesmas e de água (teste do apetite ao sódio). No teste paradigmático do sinergismo, os animais receberam injeção sc de 2,5 mg de acetato de desoxicorticosterona (DOCA) ou óleo de girassol (veículo) uma vez ao dia, durante três dias, e uma injeção de 50 ng de ANG II (ou salina) no ventrículo lateral esquerdo, quatro horas após a última injeção de DOCA ou óleo. Passou-se a registrar a ingestão de líquidos imediatamente após a injeção de ANG II e remoção da ração. O registro da ingestão diária mostrou que não houve preferência por nenhuma solução ou água durante o período de ambientação com cinco bebedouros. A depleção de sódio induziu ingestão preferencial de sódio no teste do apetite ao sódio, sendo a ingestão de NaCl 0,15 M maior do que a de NaHCO3 tanto nos testes de dois como de cinco bebedouros. O tratamento com apenas DOCA aumentou a ingestão diária de NaCl 0,15 M e de NaHCO3 sem alterar a ingestão diária de KCl e de NaCl 0,50 M, em testes de dois bebedouros. No teste paradigmático com ratos normovolêmicos, a ANG II combinada ao óleo promoveu ingestão das três soluções minerais palatáveis (KCl, NaHCO3, NaCl) e de água em testes de dupla escolha, e preferência ao NaHCO3 no teste com cinco bebedouros. O pré-tratamento com DOCA potenciou o efeito da ANG II apenas sobre a ingestão das soluções sódicas, mais evidente para NaCl, no teste com dois bebedouros (NaCl 0,15 M: DOCA/ANG II = 24,5 ± 6,7 ml/120 min. vs. ÓLEO/ANG II = 9,2 ± 1,8 ml/120 min.; NaHCO3 0,15 M: DOCA/ANG II = 17,0 ± 1,8 ml/120 min. vs. ÓLEO/ANG II = 14,6 ± 2,1 ml/120 min.; KCl 0,01 M: DOCA/ANG II = 9,8 ± 1,9 ml/120 min. vs. 11,9 ± 1,2 ml/120 min.), além de aumentar em 80 % a ingestão total de soluções sódicas no início do teste com cinco bebedouros. O efeito da indução de ingestão de NaCl 0,50 M pela combinação de DOCA com ANG II em testes de dois bebedouros foi replicado nos nossos animais. Os resultados do teste paradigmático do sinergismo são coerentes com os testes do apetite ao sódio, sugerindo que o mineralocorticóide possa tornar mais seletivo o efeito da ANG II sobre a ingestão mineral. Assim, uma interação entre ANG II e mineralocorticóide poderia contribuir para a expressão de duas características do apetite ao sódio, não apenas a aceitação de soluções hipertônicas de NaCl, mas também a ingestão seletiva de sódio.

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No. of bitstreams: 1 juliocesarmoraeslovisi.pdf: 3660990 bytes, checksum: 9bfd65df440e1a934d906a3918e427d5 (MD5) Previous issue date: 2013-09-09 / INTRODUÇÃO: A epidemia de obesidade e de síndrome metabólica (SM) observada nos últimos anos se associa a uma série de agravos clínicos como neoplasias, diabetes mellitus e doenças cardiovasculares, notadamente a hipertensão arterial (HA). Diversos mecanismos etiopatogênicos têm sido descritos na HA associada à SM entre os quais citam-se a participação da aldosterona (ALDO) e da disfunção endotelial. OBJETIVOS: avaliar os efeitos do bloqueio do receptor mineralocorticoide (RMC) na função endotelial, na pressão arterial (PA) e em parâmetros inflamatórios e renais de indivíduos com SM. PACIENTES E MÉTODOS: Foram selecionados 42 pacientes elegíveis para o protocolo. Todos os voluntários foram submetidos a exame clínico, avaliação laboratorial com dosagens de mediadores inflamatórios e de excreção urinária de albumina, além de avaliação cardiológica, com monitorização ambulatorial da pressão arterial (MAPA), ecocardiograma e estudo da vasodilatação fluxo-mediada (VDFM), antes e após o tratamento. Destes, 28 indivíduos foram tratados com espironolactona (ESPIRO) na dose de 25-50 mg/dia e 14 com amlodipina (AMLO) na dose 5-10 mg/dia por 16 semanas (Resultados 1). Após essa avaliação, com objetivo de homogeneizar os grupos para melhor comparação dos parâmetros de VDFM, inflamatórios e renais, foram selecionados 27 indivíduos alocados em dois grupos por meio da aplicação da técnica do Propensity Score (PS). Deste modo foram constituídos dois grupos homogêneos, a saber: 16 pacientes em um grupo tratado com ESPIRO e 11 no grupo controle, tratados com AMLO, por um período de 16 semanas (Resultados 2). Resultados 1: Os dados iniciais mostraram que o tratamento da HA com ESPIRO e com AMLO resultou em redução significante da PA em ambos os grupos. No grupo ESPIRO foi observado aumento da VDFM, enquanto no grupo AMLO houve redução significativa desse parâmetro. Observamos ainda redução significativa da microalbuminúria e de mediadores inflamatórios no grupo ESPIRO, o que não ocorreu no grupo AMLO. Finalmente, observou- se aumento significativo do colesterol HDL no grupo ESPIRO o que não foi observado no grupo AMLO. Resultados 2: com a aplicação do PS e consequente maior homogeneidade entre os grupos houve a confirmação desses achados nos 2 grupos (ESPIRO e AMLO) e, adicionalmente, permitiu a subdivisão destes em inflamados (PCR>3,0 mg/dL) e não inflamados (PCR < 3,0 mg/dL). Quando se avaliaram a VDFM, o comportamento pressórico e de parâmetros metabólicos e renais observou-se aumento da VDFM, maior redução da PA, aumento do colesterol HDL e redução da albuminúria que foram significativas no grupo ESPIRO, notadamente no subgrupo não inflamado em comparação ao grupo inflamado. CONCLUSÃO: O bloqueio dos RMC em hipertensos com SM melhorou a função endotelial e reduziu a pressão arterial, com impacto favorável sobre marcadores metabólicos, inflamatórios e na excreção urinária de albumina. Estes achados apontam para efeitos benéficos adicionais à redução pressórica em pacientes portadores de SM tratados com bloqueadores dos RMC. / INTRODUCTION: The epidemic of obesity and metabolic syndrome (MS) described in recent years is associated with a series of clinical conditions such as malignancy, diabetes mellitus, and cardiovascular diseases, chiefly systemic arterial hypertension (AH). There are several mechanisms proposed to explain the development of MS-associated AH, among which the role of aldosterone and endothelial dysfunction are noteworthy. OBJECTIVES: assess the effects of mineralocorticoid receptor blockade (MRB) on endothelial function, blood pressure (BP) and inflammatory and renal parameters of individuals with the MS. PATIENTS AND METHODS: Forty-two eligible patients were selected. All volunteers underwent clinical examination, laboratory determination of inflammatory mediators and urinary albumin excretion, and cardiologic examination with 24-hour ambulatory blood pressure (24-h ABPM), echocardiography and assessment of the flow-mediated vasodilation (FMD) at baseline and after treatment. Twenty-eight individuals received spironolactone (SPIRO), 25-50mg/day, and 14 individuals received amlodipine (AMLO), 5-10mg/day, for 16 weeks (Results 1). In order to homogenize the groups and better compare the FMD and the inflammatory and renal parameters, 27 individuals were selected and allocated to two groups according to the propensity score (PS) technique: 16 individuals treated with SPIRO and 11 controls, treated with AMLO, for 16 weeks (Results 2). Results 1: Both SPIRO-treated and AMLO-treated groups had significant BP reductions. While the SPIRO-treated group had increased FMD, the AMLO-treated group had a significant reduction of this parameter. There was also a significant reduction of microalbuminuria and inflammatory mediators in the SPIRO-treated group, but not in the AMLO one. There was a significant increase of HDL-cholesterol in the SPIRO group, but not in the AMLO one. Results 2: With the PS technique, and consequent better homogenization of the groups, we confirmed these findings in the two groups (SPIRO and AMLO) and further subdivided them into those with inflammation (CRP>3.0mg/dl) and those without inflammation (CRP<3.0mg/dl). There were significantly increased FMV, greater BP reduction, increased HDL-cholesterol, and significant reduction of albuminuria in the SPIRO group, notably in the subgroup without inflammation, as compared with that with inflammation. CONCLUSION: MRB in hypertensive subjects with the MS improved endothelial function and reduced blood pressure, with a favorable impact on metabolic and inflammatory markers and on the urinary albumin excretion. These findings point to MRB as a new option for treatment of AH in individuals with the MS.

Au cours de ma thèse, je me suis principalement intéressée aux interactions entre les systèmes angiotensine et gluco-minéralocorticoïde dans la paroi artérielle et particulièrement dans la physiopathologie du remodelage artériel. Pour cela, nous avons étudié les mécanismes moléculaires aboutissant au développement de l’athérome et qui impliqueraient ces deux systèmes. Notre hypothèse est qu’un excès local en gluco-et/ou minéralocorticoïdes dans la paroi favorise le développement de l’athérome en stimulant le système angiotensine. Nos résultats ont confirmé l’expression des éléments nécessaires à la synthèse et à l'action des gluco-minéralocorticoïdes dans la paroi carotidienne humaine et dans les CMLV, avec une prévalence de la voie des glucocorticoïdes. Cette prédominance se manifeste par l’effet stimulant du cortisol sur l’expression des marqueurs des processus fibrosants, lipogéniques et inflammatoire mis en jeu lors de la formation de l’athérome. La relation entre le taux d’expression pariétale de GRα et 11β-HSD1 d’une part et le collagène 1 d’autre part suggère une contribution majeure des glucocorticoïdes dans la rigidité artérielle. Il a également été observé que le cortisol a un effet stimulant sur l’expression du collagène dans les CMLV suggérant ainsi que le cortisol favoriserait la survenue des accidents cardiovasculaires. La relation inverse entre le taux d’expression pariétal de GRα et la mesure de la pression artérielle diastolique est en faveur de cette hypothèse. De même, l’augmentation du taux de l’ARNm de GRα chez les patients ayant fait un accident cardiovasculaire corrobore l’hypothèse d’un rôle délétère des glucocorticoïdes dans le remodelage athéromateux. Nos résultats montrent que le système glucocorticoïde est un puissant stimulateur du système angiotensine pariétal et suggère l’existence d’une régulation commune de la synthèse de l’angiotensine II, de l’aldostérone et du cortisol évoquant ainsi la possibilité d’interactions entre les systèmes angiotensine et gluco-minéralocorticoïde pariétaux. Par ailleurs, les concentrations basses du cortisol plasmatique chez les patients traités par des bloqueurs du système rénine angiotensine est en faveur de la théorie d’amplification mutuelle des systèmes angiotensine et glucocorticoïde. Notre étude souligne l’intérêt des bloqueurs du SRA comme approche thérapeutique préférentielle à utiliser afin d’atténuer les effets délétères du cortisol, améliorer le risque cardiovasculaire et le pronostic des patients / The involvement of the renin angiotensin system, cortisol and aldosterone in the increase of cardiovascular risk is well known as well as some of relationships between RAS and corticosteroids but their interactions within arterial wall and particularly during atheroma formation are not established. Considering all these data, we hypothesize that an increase in local gluco-and/or mineralocorticoid synthesis and activity within the arterial wall may favour atheroma development by stimulating tissue angiotensin system. Our results give argument in favour of an independence betweenthe parietal and endocrine corticosteroid systems. We have shown the prevailing involvement of the glucocorticoid pathway in the atherosclerotic remodelling both in terms of intra-parietal expression and regulation of fibrotic, inflammatory and lipogenic effects in VSMCs together with the further amplification of this involvement after adipocyte dedifferentiation of VSMCs. There is modulation of GR and MR effects with a change in the cell pathophysiological state. Interestingly, there is no “illicit” cortisol-dependent activation of MR-receptor. We conclude that cortisol involvement in atheroma formation could pass apart from its continuing stimulating effect on its own synthesis and action, through mutual stimulating effects of cortisol and angiotensin II on their reciprocal compounds. These processes could already take place at the initial stage of atheroma and might intensify as the atheroma development progresses. The up-regulation of parietal angiotensin system could be revealed by a low plasma renin. The lower plasma cortisol levels in patients on RAS blocker treatment corroborates the thesis of mutual amplification of effects between glucocorticoids and angiotensin system, and this treatment would be particularly beneficial in essential hypertensive patients with low plasma renin, to attenuate both angiotensin II and also cortisol up-regulation

Le système rénine-angiotensine-aldostérone est impliqué dans la physiopathologie de l’insuffisance cardiaque (IC). L’inhibition de l’aldostérone par les antagonistes du récepteur aux minéralocorticoïdes (ARM), la spironolactone et l’éplérénone, est associée à une réduction de morbidité et mortalité. Or, la spironolactone est un antagoniste non sélectif, avec des effets hors-cibles sur d’autres récepteurs stéroïdiens. Des données suggèrent qu’elle pourrait avoir un effet défavorable sur l’homéostasie du glucose, avec une augmentation en hémoglobine glyquée (HbA1c), un marqueur de contrôle du glucose à long terme. Au contraire, l’éplérénone semble exercer un effet neutre. Les objectifs de cette thèse de doctorat sont les suivants : 1) Assembler toutes les connaissances dans la littérature au sujet de l’effet glycémique des ARM; 2) Évaluer le risque de développement de diabète avec la spironolactone chez les patients IC; 3) Analyser si la spironolactone peut moduler l’effet glycémique d’autres médicaments utilisés en IC; 4) Comparer la spironolactone à l’éplérénone sur des marqueurs de glucose chez les patients IC avec dérèglements glycémiques. Quatre projets ont été effectués afin de répondre à ces questions. Premièrement, une revue systématique a permis d’identifier toutes les études publiées contenant de l’information sur l’effet glycémique des ARM. Les résultats étaient hétérogènes, mais ont suggéré que l’effet est dépendant de la pathologie et serait potentiellement néfaste dans les maladies à haut risque d’évènements cardiovasculaires. Une méta-analyse d’études en diabète indique que l’effet à long terme serait non significatif. Le deuxième projet utilise une cohorte de patients IC de bases de données administratives entre 1995 et 2009 (suivi jusqu’en 2010). Nous n’avons pas détecté d’association significative entre l’utilisation de la spironolactone et le risque de diabète. Par contre, l’étude a démontré qu’un âge plus jeune, la digoxine, et les corticostéroïdes augmentent le risque de diabète. Le troisième projet est une sous-étude d’une étude clinique CANDIID-II (Effect of ACE inhibitor alone versus ACE inhibitor plus high dose candesartan on BNP, immune markers, inflammatory status, and urinary kinins in patients with symptomatic left ventricular systolic dysfunction) chez des patients IC traités avec un inhibiteur de l’enzyme de conversion à l’angiotensine et le candésartan, antagoniste du récepteur à l’angiotensine II. Ces classes pharmacologiques ont des effets bénéfiques sur la glycémie. En comparant les patients traités aussi avec la spironolactone versus les patients sans ARM, nous n’avons pas trouvé que la spironolactone module l’effet bénéfique du candésartan sur le métabolisme du glucose. Le dernier projet consiste d’une étude prospective, multicentrique, randomisée, contrôlée à double-insu : SNOW (A comparison of the effects of selective and non selective mineralocorticoid antagonism on glucose homeostasis and lipid profile of heart failure patients with glucose intolerance or type 2 diabetes). Elle compare, pendant 16 semaines, la spironolactone à l’éplérénone sur des marqueurs glycémiques, notamment, l’HbA1c, chez 62 patients IC avec diabète de type II ou intolérance au glucose. Aucune différence significative n’a été observée entre les groupes. En résumé, les résultats de cette thèse indiquent que les ARM ne présentent pas de risque de détérioration du contrôle du glucose sur une durée modérée à longue en IC. / The renin-angiotensin-aldosterone system is involved in the pathophysiology of heart failure (HF). The inhibition of aldosterone by mineralocorticoid receptor antagonists (MRAs), spironolactone and eplerenone, is associated with a reduction in morbidity and mortality. However, spironolactone is a non selective antagonist, with off-target effects on other steroid receptors. There is some evidence suggesting that it may have an unfavorable effect on glucose homeostasis, with an increase in glycated hemoglobin (HbA1c), a marker of long-term glucose control. On the contrary, eplerenone seems to exert a neutral effect. The objectives of this doctoral thesis were the following: 1) Compile all current knowledge in the literature on the subject of MRAs’ glycemic effects; 2) Evaluate the risk of developing diabetes with spironolactone in HF patients; 3) Analyze if spironolactone may modulate the glycemic effects of other medications used in HF; 4) Compare spironolactone to eplerenone on markers of glucose control in HF patients with glycemic disorders. Four projects were conducted in order to meet these objectives. Firstly, a systematic review allowed us to identify all published studies containing information on MRAs’ glycemic effects. The literature search yielded heterogenous results; however, it suggested that the effect was disease-specific and would be potentially harmful in diseases with a high risk of cardiovascular events. A meta-analysis of studies in diabetes insinuated that the effect is non significant on a long-term basis. The second project uses a cohort of HF patients from administrative databases between 1995 and 2009 (follow-up till 2010). We did not detect a significant association between the use of spironolactone and the risk of diabetes. On the other hand, the study demonstrated that younger age, digoxin, and corticosteroids increase the risk of diabetes. The third project is a substudy of a clinical trial CANDIID-II (Effect of ACE inhibitor alone versus ACE inhibitor plus high dose candesartan on BNP, immune markers, inflammatory status, and urinary kinins in patients with symptomatic left ventricular systolic dysfunction) among HF patients treated with an angiotensin converting enzyme inhibitor and candesartan, an angiotensin II receptor blocker. These pharmacological classes have beneficial effects on glycemia. By comparing patients also treated with spironolactone versus patients without an MRA, we did not find that spironolactone alters the effect of candesartan on glucose metabolism. The last project consisted of a prospective, multicenter, randomized, controlled, double-blind trial: SNOW (A comparison of the effects of selective and non selective mineralocorticoid antagonism on glucose homeostasis and lipid profile of heart failure patients with glucose intolerance or type 2 diabetes). It compares, for 16 weeks, spironolactone to eplerenone on glycemic markers, notably, HbA1c, among 62 HF patients with type II diabetes or glucose intolerance. There was no significant difference between groups. In summary, the research results from this thesis reveal that, in HF, MRAs do not present additional risks of deterioration in glucose control over a moderate to long period.