Les conséquences cardiovasculaires du vieillissement sont l'une des principales causes de mortalité. En plus de l'âge chronologique, plusieurs autres facteurs peuvent influencer l'apparition des modifications liées au vieillissement. L'étude des déterminants génétiques et environnementaux accélérateurs du vieillissement cardiovasculaire pourrait améliorer la prévention de ces pathologies. Nous avons démontré chez le rat Zucker (modèle de syndrome métabolique) en fin de vie (80 semaines) que l'obésité et les troubles métaboliques associés et le vieillissement agissent de façon synergique pour modifier la structure et la fonction vasculaire, en ciblant les propriétés endothéliales. L'augmentation précoce des acides gras libres (AGL) plasmatiques et les altérations de réactivité carotidienne qu'ils induisent sont des mécanismes clés du développement de la rigidité artérielle dans ce modèle. La souris déficiente pour le gène Klotho (Kl) possède une faible espérance de vie, un vieillissement accéléré et des pathologies semblables à celles de l'homme âgé. Nous avons caractérisé le phénotype artériel (peu connu) des souris Kl+/- à 6 et 12 mois, en comparaison de leurs contrôles Kl+/+ aux mêmes âges. Nous avons démontré dans ce modèle que dans des conditions basales, les souris Kl+/- ne présentent pas de phénotype de vieillissement accéléré de la paroi artérielle à l'âge de 12 mois. Néanmoins, à l'âge de 6 mois, les souris Kl+/- présentent une augmentation de leur rigidité carotidienne, en faveur d'une altération de la fonction vasculaire. L'étude de ces deux modèles nous a ainsi permis d'évaluer l'implication de l'obésité et de la protéine Klotho dans le vieillissement artériel / The cardiovascular consequences of aging are a leading cause of death. In addition to chronological age, several other factors may influence the onset of changes associated with aging. The study of genetic and environmental determinants of cardiovascular aging accelerators could improve prevention of these diseases. We have demonstrated in very old (80 weeks) Zucker rats (model of metabolic syndrome) that obesity and associated metabolic disorders act synergistically with aging to alter the vascular structure and function by targeting endothelial properties. The early increase in plasma free fatty acids (FFA) and alterations in carotid responsiveness induced by AGL are key mechanisms of development of arterial stiffness in this model. Mouse deficient for the gene Klotho (Kl) has a short life expectancy, accelerated aging and diseases similar to an old man. We characterized the arterial phenotype (unknown) mice Kl +/- at 6 and 12 months, compared to their controls K +/+ at the same ages. We have demonstrated in this model that in basal conditions, Kl +/- mice show no phenotype of an accelerated aging of the arterial wall at the age of 12 months. However, at the age of 6 months, mice Kl +/- show an increase in carotid stiffness in favor of an alteration of vascular function. The study of these two models has allowed us to assess the implication of obesity and Klotho protein in aging arteries

Ce projet traite de la programmation développementale de l'hypertension artérielle (HTA) à travers des influences néonatales précoces pouvant moduler le développement vasculaire. Les bébés prématurés présentent des défenses antioxydantes diminuées comparés aux nouveau-nés à terme et sont exposés à la naissance à des concentrations élevées en oxygène (O2) engendrant la production d'espèces réactives de l'O2 (ERO). Les conséquences vasculaires à long terme de dommages liés aux ERO en période néonatale et les mécanismes impliqués sont très partiellement compris. Les précédents résultats du laboratoire ont montré qu'un stress hyperoxique néonatal conduit chez le rat adulte à de l'HTA, une dysfonction endothéliale et une rigidité artérielle, éléments de vieillissement vasculaire. Nous émettons l'hypothèse qu'un stress hyperoxique néonatale conduit à long terme à l'altération de la structure vasculaire et à un vieillissement vasculaire précoce. Nous avons démontré une diminution de la prolifération cellulaire, une capacité angiogénique altérée, des dommages à l'ADN et une augmentation de l'expression de protéines de sénescences (des indices de sénescence cellulaire) au-delà de la période néonatale suite à une exposition brève à l'O2 au niveau vasculaire dans un modèle animal (ratons Sprague-Dawley exposés à 80 % d'O2 du 3ème au 10ème jour de vie comparés à des ratons restés à l'air ambiant) et cellulaire (cellules musculaires lisses d'aortes thoraciques d'embryon de rat exposées à 40% O2 pendant 24h ou 48h, puis remises en normoxie pendant 96h). De plus, des altérations des composants de la structure vasculaire indiquant un remodelage vasculaire aortique ont été mises en évidence. Ces changements précèdent tous l'HTA et la dysfonction vasculaire observées dans le modèle animal à l'âge adulte et pourraient y contribuer. L'étude de jeunes adultes nés < 29 semaines comparés à des jeunes adultes nés à terme indique une augmentation de marqueurs de rigidité artérielle (indices d'un vieillissement vasculaire précoce) chez la population prématurée. L'ensemble des résultats démontre un vieillissement vasculaire précoce après une exposition néonatale transitoire à un stress hyperoxique permettant une meilleure compréhension des mécanismes physiopathologiques impliqués dans la survenue des troubles vasculaires retrouvés chez l'adulte et contribue à la mise en place de moyens de prévention chez des patients prématurés / The scope of this thesis is developmental programming of arterial high blood pressure (HBP) hypertension through early neonatal stimuli that may alter vascular development. Premature newborns have decreased antioxidant defenses compared to term babies and are exposed upon birth to high oxygen (O2) concentration, causing reactive oxygen species (ROS) production. Long term vascular consequences of ROS related damage during the neonatal period and the mechanisms involved remain unknown. Recent data from the laboratory show that neonatal hyperoxic stress leads in adult rat to HBP, endothelial dysfunction and arterial rigidity, characteristic features of vascular aging. We hypothesize that a neonatal hyperoxic stress leads to long term vascular structure alteration explained by an early aging of the vascular system. We showed a decreased proliferation rate, an altered angiogenic capacity, as well as long term DNA damage and increased expression of senescence proteins at a vascular level following O2 exposure in the animal (male Sprague-Dawley pups kept at 80% O2 from postnatal days 3 to 10 vs. rats remained in room air) and cellular models (embryonic vascular smooth muscle cells from rat thoracic aorta exposed to 40% O2 for 24h or 48h followed by 96h recovery in control conditions). In addition, alterations of vascular structure components indicating vascular remodeling was shown before the onset of the HBP at adult age. Those changes precede the HBP and vascular dysfunction observed in our animal model at adult age and could contribute to them. Study of young adults born before 29 weeks vs. young adults born at term showed that young adults born preterm present indices of arterial stiffness vs. term controls. Results of the present thesis demonstrate a major role of premature vascular aging in the surge of vascular diseases in adulthood and contribute to a better understanding of the patho-physiological mechanisms involved and could put into practice new prevention strategies among preterm patients

INTRODUÇÃO: Alterações neurovasculares presentes na hipertensão arterial são minimizadas pelo treinamento físico em hipertensos previamente sedentários. Entretanto, é desconhecido se atletas hipertensos apresentam alterações neurovasculares ou se o treinamento físico previne tais danos. Este estudo avaliou o controle neurovascular de corredores hipertensos, durante o treinamento competitivo, assim como o efeito de 4 meses de treinamento de intensidade moderada nesta população. MÉTODOS: 37 corredores, homens (20 normotensos, 43 +-1 anos e 17 hipertensos, 42+-1 anos), foram avaliados no treinamento competitivo e posteriormente divididos em 4 subgrupos: normotensos que mantiveram treinamento competitivo (n=10); normotensos que realizaram treinamento de intensidade moderada (n=10); hipertensos que mantiveram treinamento competitivo (n=8); hipertensos que realizaram treinamento de intensidade moderada (n=8). Após 4 meses de intervenção, todos os corredores foram novamente avaliados. Atividade nervosa simpática muscular (ANSM) (microneurografia), propriedades arteriais (velocidade da onda de pulso (VOP) e sistema echo-tracking de alta resolução), controle barorreflexo da frequência cardíaca (FC) e da ANSM (infusão de drogas vasoativas) foram avaliados. RESULTADOS: Corredores hipertensos apresentaram maior pressão arterial sistólica (P < 0,001), diastólica (PAD) (P < 0,001) e média (PAM) (P < 0,001) que corredores normotensos. A ANSM foi maior no grupo hipertenso (disparos/min.; P=0,02 e disparos/100 batimentos; P=0,004) em relação ao grupo normotenso. Não houve diferença na VOP (P=0,71) e nas variáveis da carótida: espessura intima-média (P=0,18), diâmetro (P=0,09) e distensão (P=0,79) entre os grupos. A equação sigmoidal para controle barorreflexo da FC, mostrou menor ganho barorreflexo nos corredores hipertensos em relação aos normotensos (resetting) (P=0,002). O controle barorreflexo da FC, avaliado pela análise de regressão linear, não foi diferente entre os grupos, para aumento (slope P=0,41; intercepto P=0,31) e queda (slope P=0,16; intercepto P=0,73) da PAM. Similarmente, o controle barorreflexo da ANSM foi semelhante entre corredores normotensos e hipertensos, para aumento (slope P=0,65; intercepto P=0,51) e queda (slope P=0,91; intercepto P=0,80) da PAM. Após 4 meses, os dois subgrupos de corredores hipertensos apresentaram maior delta de queda da PAD (P < 0,02) e PAM (P < 0,02), quando comparados com os dois subgrupos de corredores normotensos. O treinamento de intensidade moderada ocasionou diminuição no delta da ANSM (P=0,015) no subgrupo de corredores hipertensos, assim como melhorou o controle barorreflexo da ANSM para aumento da PAM (slope P=0,03) nos subgrupos de normotensos e hipertensos, quando comparados com os subgrupos que mantiveram o treinamento competitivo. A manutenção do treinamento competitivo, em ambos os subgrupos de normotensos e hipertensos, ocasionou mudança no delta do intercepto do controle barorreflexo da FC, para aumento da PAM (P=0,04), quando avaliado pela regressão linear. Em relação às propriedades arteriais, ambos os treinamentos não ocasionaram modificações (P > 0,05). CONCLUSÕES: Corredores hipertensos apresentam ANSM elevada, mas manutenção das propriedades elásticas arteriais e do controle barorreflexo da FC e da ANSM, sugerindo um efeito positivo parcial do treinamento físico competitivo. Por outro lado, o treinamento de intensidade moderada é capaz de diminuir a ANSM dos corredores hipertensos e de melhorar o controle barorreflexo da ANSM, tanto em corredores hipertensos, quanto em corredores normotensos / INTRODUCTION: Neurovascular alterations presented in hypertension are minimized by physical training in previously sedentary hypertensive. However it is unknown if hypertensive athletes present neurovascular alterations or if physical training prevents these damages. This study evaluated the neurovascular control of hypertensive runners during competitive training as well as the effect of 4 months of moderate intensity training in this population. METHODS: 37 runners, male (20 normotensive, 43+-1 years old and 17 hypertensive, 42+-1 years old), were evaluated during competitive training and after that were divided in 4 subgroups: normotensive who maintained competitive training (n=10); normotensive who performed moderate intensity training (n=10); hypertensive who maintained competitive training (n=8); hypertensive who performed moderate intensity training (n=8). After 4 months of intervention, all the runners were evaluated again. Muscle sympathetic nerve activity (MSNA) (microneurography), arterial properties (pulse wave velocity (PWV) and high-resolution echo-tracking system), baroreflex control of heart rate (HR) and MSNA (infusion of vasoactive drugs) were evaluated. RESULTS: Hypertensive runners had higher systolic (P < 0.001), diastolic (DAP) (P < 0.001) and mean (MAP) (P < 0.001) arterial pressure than normotensive runners. MSNA was higher in hypertensive group (bursts/min.; P=0.02 and bursts/100 heart beats; P=0.004) than in normotensive group. There was no difference in PWV (P=0.71) and carotid variables: intima-media thickness (P=0.18), diameter (P=0.09) and distension (P=0.79) between groups. The gain of baroreflex control of HR, evaluated by sigmoidal logistic equation was lower in hypertensive runners than normotensive runners (resetting) (P=0.002). Baroreflex controf of HR, evaluated by linear equation analysis, was not different between groups during increase (slope P=0.41; intercept P=0.31) and decrease (slope P=0.16; intercept P=0.73) of MAP. Similarly, there was no difference between normotensive and hypertensive runners for baroreflex control of MSNA during increase (slope P=0.65; intercept P=0.51) and decrease (slope P=0.91; intercept P=0.80) of MAP. After 4 months, both hypertensive subgroups presented higher delta of decrease in DAP (P < 0.02) and MAP (P < 0.02), when compared to both normotensive subgroups. Moderate intensity training decreased MSNA (P=0.015) in hypertensive subgroup and improved baroreflex control of MSNA (slope P=0.03) in both normotensive and hypertensive subgroups when compared to competitive training subgroups. The intercept delta for baroreflex control of HR, in both normotensive and hypertensive competitive training subgroups, was changed during increase of MAP (P=0.04), when evaluated by linear equation. Arterial properties were not modified by competitive or moderate intensity training (P > 0.05). CONCLUSIONS: Hypertensive runners show high MSNA but preserved arterial elastic properties and baroreflex control of HR and MSNA, suggesting a positive partial effect of competitive physical training. On the other hand, the moderate intensity training is able to decrease MSNA in hypertensive runners and improves baroreflex control of MSNA in hypertensive as well in normotensive runners

Introduction: Obstructive sleep apnoea (OSA) is common and is caused by repetitive obstruction of the upper airway during sleep. OSA is associated with increased cardiovascular morbidity and mortality and is an independent risk factor for hypertension. The immediate physiological effects of OSA include intermittent hypoxia, repeated arousal from sleep and intra-thoracic pressure swings. The resulting activation of the sympathetic nervous system, systemic inflammation and oxidative stress may result in increased arterial stiffness and endothelial dysfunction, potentially explaining any causal link between OSA and cardiovascular disease (CVD). Continuous positive airway pressure (CPAP) therapy improves excessive daytime sleepiness (EDS) and in non-randomised studies, reduces cardiovascular mortality. Prior to starting this study, there was a limited amount of evidence suggesting that CPAP therapy improved arterial stiffness and endothelial function, but the effects in subjects without pre-existing CVD were unclear. Aims: i) to determine whether CPAP therapy has an effect upon measures of arterial stiffness and endothelial function in patients with OSA, in the absence of known CVD. ii) To compare arterial stiffness and endothelial function in a subset of patients with OSAHS (defined as OSA and EDS), with a group of well-matched control subjects. Methods: Fifty three patients with OSA, defined as an apnoea/hypopnoea index of ≥15, and without known CVD, entered a double-blind placebo-controlled crossover trial of 12 weeks CPAP therapy, of whom forty three completed the study protocol. Sham CPAP was used in the placebo arm of the study and vascular assessments were made at baseline and after each arm of the study. Arterial stiffness was determined by measuring aortic distensibility using cardiovascular magnetic resonance imaging and by measuring the augmentation index (AIx) and aortic pulse wave velocity (PWV) by applanation tonometry. Endothelial function was assessed non-invasively by measuring vascular reactivity after administration of salbutamol and glyceryl trinitrate. In a subset of twenty patients with OSAHS, arterial stiffness and endothelial function at baseline were compared to readings obtained from healthy control subjects, matched on a one-to-one basis for age, sex and BMI. Results: Patients with OSAHS (n=20) had increased arterial stiffness [AIx 19.3(10.9) vs. 12.6(10.2) %; p=0.017] and impaired endothelial function, measured as the change in AIx following salbutamol [-4.3(3.2) vs. -8.0(4.9) %; p=0.02] compared to controls. Twelve weeks of CPAP therapy had no significant effect upon any measure of arterial stiffness or endothelial function in patients with OSA (n=43). A trend towards a reduction in AIx following CPAP therapy was seen, but this was non-significant. There was a reduction in systolic blood pressure following CPAP therapy [126(12) vs. 129(14) mmHg]. Sub group analysis showed CPAP to have no effect on arterial stiffness or endothelial function in patients with EDS or in patients using CPAP for ≥4 hours per night. Conclusions: This study demonstrates that even in the absence of known CVD, patients with OSAHS have evidence of increased arterial stiffness and impaired endothelial function. However, in patients with OSA, free from CVD, CPAP therapy did not lead to an improvement in any measure of arterial stiffness or endothelial function after 12 weeks.

A hipertensão arterial sistêmica (HAS) pós-transplante é frequente e está associada com aumento da morbimortalidade cardiovascular e subsequente disfunção do enxerto, sendo relatada como consequência ao uso de imunossupressores, especialmente os inibidores da calcineurina. Este estudo pretende avaliar o impacto da hipertensão arterial sobre a rigidez arterial calculada utilizando o índice ambulatorial de rigidez arterial (IARA) como desfecho substituto obtido pela monitorização ambulatorial da pressão arterial (MAPA) em pacientes transplantados de coração. Trata-se de um estudo prospectivo, observacional, analítico, com grupo controle, realizado no Hospital de Messejana Dr. Carlos Alberto Studart Gomes, hospital público do estado do Ceará, especializado em doenças cardiopulmonares e de referência em transplante de coração. Foram selecionados pacientes adultos transplantados do coração, os quais passaram por exames clínicos e complementares, e um grupo controle com pacientes não transplantados hipertensos. Todos foram submetidos a MAPA e obtenção do IARA com o objetivo de estimar o risco de rigidez arterial. Foram realizados testes estatísticos de significância e regressão logística para controle de confundimento. A média de idade dos transplantados foi de 55 anos, contra 48 dos não transplantados. A hipertensão prévia foi mais frequente em não transplantados, mas diabetes e doença arterial coronariana foram mais frequentes em transplantados. A média diastólica dos transplantados (82) é significativamente maior que a dos não transplantados (74) e o descenso sistólico é praticamente inexistente em pacientes transplantados (-0,18) que no grupo-controle (9,45). A condição de transplantado do paciente não é determinante de rigidez arterial, mas a hipertensão arterial sistólica na primeira avaliação, a média sistólica em 24h, a média diastólica em 24h, o descenso sistólico, o descenso diastólico e o IARA (parâmetros da MAPA) o são. Este estudo encontrou que num grupo de transplantados de coração adultos, a hipertensão arterial sistêmica está independentemente associada com a rigidez arterial estimada pelo IARA, que é um novo método, não invasivo, de fácil execução e de baixo custo. A evidência demonstrada por este estudo pode auxiliar no direcionamento de tratamento dos pacientes transplantados, contribuindo com melhoria do prognóstico / Hypertension post cardiac transplant is frequent and is associated with increased cardiovascular morbidity and mortality and graft dysfunction, being reported because of the use of immunosuppressant, especially the calcineurin inhibitors. This study aims to evaluate the impact of hypertension on the arterial stiffness calculated using the IARA as surrogate outcome obtained by the Home Blood Pressure Monitoring in heart transplanted patients. This is an observational study, analytical, with the control group, in Heart and Lung Messejana´s Hospital, a public institution in the State of Ceará, which is specialized in cardiopulmonary diseases and especially in heart transplant, with adult patients cardiac transplanted, which underwent clinical and complementary exams, from which were obtained the IARA. Statistical significance tests and logistic regression to control for confounding were performed. The average age of transplanted was 55 years, against 48 of the non-transplanted. Hypertension was more frequent in prior not transplanted, but diabetes and coronary artery disease were more frequent in transplanted. The average diastolic of transplanted (82) is significantly higher than the non-transplanted (74) and decrease systolic is virtually nonexistent in transplant patients (-0.18) than in the control group (9.45). The condition of the transplanted patient is not determinant of arterial stiffness (p = 0.105), but are the systolic hypertension in the first evaluation, the average systolic, diastolic average in 12:0 am 12:0 am, systolic, diastolic descent and the IARA (parameters of the HBPM). This study showed that in a group of adult cardiac transplanted, hypertension is independently associated with arterial stiffness estimated by IARA, which is a new method, non-invasive, easy to perform and inexpensive. The evidence demonstrated by this study may assist in treatment of transplanted patients, contributing to improving the prognosis

INTRODUÇÃO: Alterações neurovasculares presentes na hipertensão arterial são minimizadas pelo treinamento físico em hipertensos previamente sedentários. Entretanto, é desconhecido se atletas hipertensos apresentam alterações neurovasculares ou se o treinamento físico previne tais danos. Este estudo avaliou o controle neurovascular de corredores hipertensos, durante o treinamento competitivo, assim como o efeito de 4 meses de treinamento de intensidade moderada nesta população. MÉTODOS: 37 corredores, homens (20 normotensos, 43 +-1 anos e 17 hipertensos, 42+-1 anos), foram avaliados no treinamento competitivo e posteriormente divididos em 4 subgrupos: normotensos que mantiveram treinamento competitivo (n=10); normotensos que realizaram treinamento de intensidade moderada (n=10); hipertensos que mantiveram treinamento competitivo (n=8); hipertensos que realizaram treinamento de intensidade moderada (n=8). Após 4 meses de intervenção, todos os corredores foram novamente avaliados. Atividade nervosa simpática muscular (ANSM) (microneurografia), propriedades arteriais (velocidade da onda de pulso (VOP) e sistema echo-tracking de alta resolução), controle barorreflexo da frequência cardíaca (FC) e da ANSM (infusão de drogas vasoativas) foram avaliados. RESULTADOS: Corredores hipertensos apresentaram maior pressão arterial sistólica (P < 0,001), diastólica (PAD) (P < 0,001) e média (PAM) (P < 0,001) que corredores normotensos. A ANSM foi maior no grupo hipertenso (disparos/min.; P=0,02 e disparos/100 batimentos; P=0,004) em relação ao grupo normotenso. Não houve diferença na VOP (P=0,71) e nas variáveis da carótida: espessura intima-média (P=0,18), diâmetro (P=0,09) e distensão (P=0,79) entre os grupos. A equação sigmoidal para controle barorreflexo da FC, mostrou menor ganho barorreflexo nos corredores hipertensos em relação aos normotensos (resetting) (P=0,002). O controle barorreflexo da FC, avaliado pela análise de regressão linear, não foi diferente entre os grupos, para aumento (slope P=0,41; intercepto P=0,31) e queda (slope P=0,16; intercepto P=0,73) da PAM. Similarmente, o controle barorreflexo da ANSM foi semelhante entre corredores normotensos e hipertensos, para aumento (slope P=0,65; intercepto P=0,51) e queda (slope P=0,91; intercepto P=0,80) da PAM. Após 4 meses, os dois subgrupos de corredores hipertensos apresentaram maior delta de queda da PAD (P < 0,02) e PAM (P < 0,02), quando comparados com os dois subgrupos de corredores normotensos. O treinamento de intensidade moderada ocasionou diminuição no delta da ANSM (P=0,015) no subgrupo de corredores hipertensos, assim como melhorou o controle barorreflexo da ANSM para aumento da PAM (slope P=0,03) nos subgrupos de normotensos e hipertensos, quando comparados com os subgrupos que mantiveram o treinamento competitivo. A manutenção do treinamento competitivo, em ambos os subgrupos de normotensos e hipertensos, ocasionou mudança no delta do intercepto do controle barorreflexo da FC, para aumento da PAM (P=0,04), quando avaliado pela regressão linear. Em relação às propriedades arteriais, ambos os treinamentos não ocasionaram modificações (P > 0,05). CONCLUSÕES: Corredores hipertensos apresentam ANSM elevada, mas manutenção das propriedades elásticas arteriais e do controle barorreflexo da FC e da ANSM, sugerindo um efeito positivo parcial do treinamento físico competitivo. Por outro lado, o treinamento de intensidade moderada é capaz de diminuir a ANSM dos corredores hipertensos e de melhorar o controle barorreflexo da ANSM, tanto em corredores hipertensos, quanto em corredores normotensos / INTRODUCTION: Neurovascular alterations presented in hypertension are minimized by physical training in previously sedentary hypertensive. However it is unknown if hypertensive athletes present neurovascular alterations or if physical training prevents these damages. This study evaluated the neurovascular control of hypertensive runners during competitive training as well as the effect of 4 months of moderate intensity training in this population. METHODS: 37 runners, male (20 normotensive, 43+-1 years old and 17 hypertensive, 42+-1 years old), were evaluated during competitive training and after that were divided in 4 subgroups: normotensive who maintained competitive training (n=10); normotensive who performed moderate intensity training (n=10); hypertensive who maintained competitive training (n=8); hypertensive who performed moderate intensity training (n=8). After 4 months of intervention, all the runners were evaluated again. Muscle sympathetic nerve activity (MSNA) (microneurography), arterial properties (pulse wave velocity (PWV) and high-resolution echo-tracking system), baroreflex control of heart rate (HR) and MSNA (infusion of vasoactive drugs) were evaluated. RESULTS: Hypertensive runners had higher systolic (P < 0.001), diastolic (DAP) (P < 0.001) and mean (MAP) (P < 0.001) arterial pressure than normotensive runners. MSNA was higher in hypertensive group (bursts/min.; P=0.02 and bursts/100 heart beats; P=0.004) than in normotensive group. There was no difference in PWV (P=0.71) and carotid variables: intima-media thickness (P=0.18), diameter (P=0.09) and distension (P=0.79) between groups. The gain of baroreflex control of HR, evaluated by sigmoidal logistic equation was lower in hypertensive runners than normotensive runners (resetting) (P=0.002). Baroreflex controf of HR, evaluated by linear equation analysis, was not different between groups during increase (slope P=0.41; intercept P=0.31) and decrease (slope P=0.16; intercept P=0.73) of MAP. Similarly, there was no difference between normotensive and hypertensive runners for baroreflex control of MSNA during increase (slope P=0.65; intercept P=0.51) and decrease (slope P=0.91; intercept P=0.80) of MAP. After 4 months, both hypertensive subgroups presented higher delta of decrease in DAP (P < 0.02) and MAP (P < 0.02), when compared to both normotensive subgroups. Moderate intensity training decreased MSNA (P=0.015) in hypertensive subgroup and improved baroreflex control of MSNA (slope P=0.03) in both normotensive and hypertensive subgroups when compared to competitive training subgroups. The intercept delta for baroreflex control of HR, in both normotensive and hypertensive competitive training subgroups, was changed during increase of MAP (P=0.04), when evaluated by linear equation. Arterial properties were not modified by competitive or moderate intensity training (P > 0.05). CONCLUSIONS: Hypertensive runners show high MSNA but preserved arterial elastic properties and baroreflex control of HR and MSNA, suggesting a positive partial effect of competitive physical training. On the other hand, the moderate intensity training is able to decrease MSNA in hypertensive runners and improves baroreflex control of MSNA in hypertensive as well in normotensive runners

To assess the relationships of body mass index (BMI) on arterial stiffness at rest and post-maximal treadmill graded exercise testing (GXT). Forty-four apparently healthy, young adult males (22.1 ± 0.48 years) were recruited and divided into either a healthy weight (H, ≤24.9 kg/m2), overweight (OV, 24.9-29.9 kg/m2) or obese (OB, ≥29.9 kg/m2) group based on BMI. All subjects underwent arterial stiffness (carotid-femoral pulse wave velocity, cfPWV), blood pressure (BP), pulse pressure (PP), mean arterial pressure (MAP) and body composition (bioelectrical impedance analysis, BIA) measurements at rest. Following the GXT, measures of arterial stiffness (cfPWV) and BP were acquired. Resting measures of cfPWV, BMI, systolic BP, diastolic BP, MAP, and PP were significantly (p <0.05) greater in OV and OB compared with H. Compared with OV, OB had a greater BMI. Relative peak oxygen consumption (VP2peak) was greater in H compared with OV and OB (p<0.05). systolic BP was positively associated, whereas VO2peak was inversely related to cfPWV (p<0.05). No significant inter-group interactions were observed with cfPWV after the GXT. However, interactions were observed for SBP, DBP and PP (p<0.05). In young men with varying BMI, SBP and VO2peak were associated with resting cfPWV. However, similar cardiovascular responses were observed between groups after a maximal GXT.

Les maladies cardiovasculaires représentent actuellement une des premières causes de mortalité dans les pays développés liées à l’augmentation constante des facteurs de risques dans les populations. Différentes études cliniques ont montré que la rigidité artérielle était un facteur prédictif important pour ces maladies.Malheureusement, il s’avère difficile d’accéder expérimentalement à la valeur de ce paramètre. On propose une approche qui permet de déterminer numériquement la rigidité artérielle d’un réseau d’artères à partir d’un modèle monodimensionnel personnalisé de la variation temporelle de la section et du débit sanguin des artères. L’approche proposée résout le problème inverse associé au modèle réduit pour déterminer la rigidité de chaque artère, à l’aide de mesures non invasives de type IRM, echotracking ettonométrie d’aplanation.Pour déterminer la robustesse du modèle construit vis à vis de ses paramètres, une quantification d’incertitude a été effectuée pour mesurer la contribution de ceux-ci, soit seuls soit par interaction, à la variation de la sortie du modèle, ici la pression pulsée. Cette étude a montré que la pression pulsée numérique est un indicateur numérique robuste pouvant aider au diagnostic de l’hypertension artérielle.Nous pouvons ainsi offrir au praticien un outil numérique robuste et peu coûteux permettant un diagnostic précoce et fiable des risques cardiovasculaires pour tout patient simplement à partir d’un examen non invasif / Cardiovascular diseases are currently the leading cause of mortality in developed countries, due to the constant increase in risk factors in the population. Several prospective and retrospective studies have shown that arterial stiffness is an important predictor factor of these diseases. Unfortunately, these parameters are difficult to measure experimentally. We propose a numerical approach to determine the arterial stiffness of an arterial network using a patient specificone-dimensional model of the temporal variation of the section and blood flow of the arteries. The proposed approach estimates the optimal parameters of the reduced model, including the arterial stiffness, using non-invasive measurements such MRI, echotracking and tonometry aplanation. Different optimization results applied on experimental cases will be presented. In order to determine the robustness of the model towards its parameters, an uncertainty analysis hasbeen also carried out to measure the contribution of the model input parameters, alone or by interaction with other inputs, to the variation of model output, here the arterial pulse pressure. This study has shown that the numerical pulse pressure is a reliable indicator that can help to diagnose arterial hypertension.We can then provide the practitioner a robust patient-specific tool allowing an early and reliable diagnosis of cardiovascular diseases based on a non-invasive exam

Les antiangiogéniques (AAD) représentent une classe relativement récente d’anticancéreux indiqués dans un nombre croissant de cancers solides avancés. Ces traitements inhibent la voie du VEGF en amont avec le bevacizumab, un anticorps monoclonal dirigé contre le VEGF et en aval avec les inhibiteurs des tyrosines kinases des récepteurs impliqués dans cette voie de signalisation (sorafenib et sunitinib). Les AAD s’accompagnent d’effets secondaires dont le plus fréquent est l’hypertension artérielle. Ma thèse a pour objectif de mieux comprendre la physiopathologie de l’hypertension artérielle iatrogène induite par les AAD, notamment en mesurant l’effet des AAD sur les grosses artères. Le deuxième objectif est de déterminer des marqueurs précoces d’efficacité et d’optimisation de ces traitements, notamment avec un suivi thérapeutique pharmacologique (STP). Pour remplir ces objectifs nous avons mis en place une étude clinique prospective, observationnelle monocentrique dans laquelle nous avons suivi l’évolution de paramètres artériels au cours du traitement AAD avec des techniques non-invasives chez des patients atteints d’un cancer. Dans un premier travail nous avons montré qu’il y avait une augmentation précoce et cliniquement significative de la pression brachiale et centrale, de la rigidité artérielle et du diamètre carotidien sous AAD et que ces modifications étaient en partie indépendantes de la pression artérielle. Nous avons également montré que la présence d’ondes de réflexion amples et d’une rigidité aortique basse de base avant l’introduction des AAD prédisaient une augmentation de pression artérielle systolique (PAS) à un stade précoce d’exposition (coefficients de régression : 0.37[0.04-0.70] et -1.27[-2.43 ; -0.11], p<0.05 respectivement) alors qu’après une exposition chronique aux AAD, seule une rigidité artérielle basse de base prédisait une augmentation de la PAS (-2.46 [-4.02 ; -0.90], p<0.01). L’atteinte des grosses artères est positivement associée à l’évolution carcinologique. En effet une augmentation précoce de la rigidité aortique et carotidienne sous AAD étaient associées à un haut risque de progression (HR : 1.24 [1.01 ; 1.51], p=0.042 et 1.34 [1.03-1.73], p=0.027 respectivement). Dans la deuxième partie, nous avons montré à l’aide d’un modèle pharmacocinétique de population, que l’atteinte artérielle observée lors de la prise d’AAD était due à un effet pharmacologique des AAD sur les grosses artères indépendamment de l’augmentation de pression induite par les AAD. L’augmentation de rigidité artérielle était proportionnelle à la concentration plasmatique d’AAD et à l’augmentation de la pression artérielle (coefficient de corrélation standardisé : 0.37 et 0.35, p<0.01, respectivement), expliquant respectivement 13% et 11% de la variance. Nous avons également montré que la progression et la mortalité liées au cancer étaient moindre chez les patients les plus exposés aux AAD (HR : 0.60 [0.38 ; 0.97], p=0.035 et HR=0.38 [0.19-0.79], P=0.01 respectivement) et enfin, nous avons pu déterminer une concentration sérique cible qui permettra aux cliniciens d’avoir un objectif à atteindre pour optimiser l’efficacité des AAD. En conclusion, nous avons pu démontrer l’existence d’une atteinte précoce des grosses artères se traduisant par une augmentation de la rigidité artérielle et un remodelage carotidien sous traitement AAD. Cette atteinte artérielle est directement liée à un effet pharmacologique des AAD de manière indépendante de l’augmentation de pression induite par ces traitements. Nous avons montré que les altérations de la paroi artérielle ainsi que le suivi thérapeutique pharmacologique prédisaient le pronostic carcinologique. Le suivi des propriétés artérielles combinée au STP des AAD pourraient optimiser les chances d’efficacité de ces traitements. / Antiangiogenic drugs (AAD) are a relatively new class of anti-cancer therapy indicated in an increasing number of advanced solid tumors. By inhibiting the VEGF pathway, upstream with an anti-VEGF monoclonal antibody, bévacizumab, and downstream with tyrosine kinase inhibitors of receptors involved in this signaling pathway (sorafenib and sunitinib), AAD induce arterial hypertension which is the most common side effect. The principal objective of my thesis is to improve the understanding of the pathophysiology of hypertension induced by AAD, by determining the effect of AAD on large arteries. The second objective is to determine early marker of efficacy and optimization of AAD, by the use of therapeutic drug monitoring. To fulfill those objectives, we set up a clinical prospective, observational, single center study in which we followed the time-course of several arterial parameters after AAD by the use of non-invasive techniques in patients with metastatic solid tumors. In a first work we showed that brachial and central blood pressure, arterial stiffness and carotid diameter significantly increased after AAD, partly independently of blood pressure changes. We also showed that high reflection waves and low aortic stiffness at baseline (i.e. before AAD initiation) predicted early systolic blood pressure (SBP) increase (regression coefficients: 0.37[0.04; 0.70] and -1.27[-2.43; -0.11], P<0.05 respectively) while only low aortic stiffness predicted SBP increase after chronic AAD exposure (-2.46 [-4.02 ; -0.90], P<0.01). Large arteries damage under AAD is positively associated with cancer progression. Indeed, early increase of aortic and carotid stiffness after AAD were associated with a higher risk of cancer progression (HR: 1.24 [1.01; 1.51], P=0.042 and 1.34 [1.03; 1.73], P=0.027 respectively). In a second part, using a pharmacokinetic model of population, we showed that large arteries damage observed after AAD was partly due to a pharmacological effect of AAD on large arteries independently of blood pressure increase. Arterial stiffness increase was proportional to AAD blood concentration and blood pressure increase (standardized correlation coefficients: 0.37 and 0.35, P<0.01, respectively), explaining 13% and 11% of the variance respectively. We also showed that progression and mortality related to cancer were lower in patients high AAD blood concentrations (HR: 0.60 [0.38; 0.97], P=0.035 and HR=0.38 [0.19; 0.79], P=0.01 respectively). And finally, we determined a target AAD blood concentration which will allow the clinicians to have an objective to reach in order to optimize the efficacy of AAD. In conclusion, we were able to demonstrate the existence of large arteries damage translated by large arteries stiffening and a remodeling of carotid artery after AAD. This arterial damage is directly related to a pharmacological effect of AAD independently of blood pressure changes induced by these treatments. We showed that infringement of the arterial wall and the therapeutic drug monitoring predicted tumor prognosis. Thus, the monitoring of arterial properties monitoring and the therapeutic drug monitoring might optimize the chances of efficiency of AAD.

Notre travail de thèse est consacré au développement d’une nouvelle approche d’analyse du signal oscillométrique pour mesurer la pression artérielle systolique et identifier les personnes dont la paroi artérielle est anormalement rigide. L’oscillométrie, largement exploitée pour la mesure automatique non-vulnérante de la pression artérielle, repose sur l’amplitude des variations dynamiques de pression du brassard pneumatique générées par l’expansion de l’artère brachiale sous l’effet de l’onde de pouls. Nous avons d’abord effectué une revue de la littérature sur les méthodes auscultatoire et oscillométrique. La méthode auscultatoire, fondée sur la détection des bruits produits par l’artère brachiale sous le brassard, reste la référence pour la validation des moniteurs oscillométriques. Depuis la description de ces bruits par Nicolaï Korotkoff en 1905, de nombreux auteurs ont tenté d’en expliquer l’origine et d’en identifier les limites et pièges en comparaison avec la mesure intra-artérielle directe. La technique oscillométrique dérive de l’invention du sphygmographe par Etienne-Jules Marey en 1859. Les constructeurs procèdent à la validation de leurs appareils en référence aux normes internationales (ISO) sans dévoiler les algorithmes mise en œuvre. De très nombreuses approches ont été proposées, depuis des rapports déterminés empiriquement jusqu’à des réseaux de neurones en passant par divers modèles mathématiques, pour déterminer les pressions systolique et diastolique à partir de la pression moyenne mesurée sur la courbe oscillométrique. Cependant, l’oscillométrie donne des résultats variables et présente des erreurs significatives, en particulier pour la détermination de la pression systolique, notamment chez les sujets ayant des facteurs de risque cardiovasculaires.Sur la base de cette analyse, considérant que la référence reste la détection des bruits de Korotkoff, nous avons cherché à en mieux comprendre les mécanismes. Nous avons enregistré les images échographiques et le signal Doppler de l’artère brachiale sous le brassard lors de la mesure de pression artérielle chez des sujets volontaires, en synchronisation avec l’ECG, la pression du brassard et les bruits de Korotkoff. Nous avons pu observer les variations cycliques du diamètre de l’artère brachiale pendant le dégonflage du brassard, et mesurer la vitesse locale de propagation de l’onde de pouls, ainsi que les délais entre le signal oscillométrique, l’ECG et les bruits de Korotkoff. Nous avons pu ainsi démontrer que les bruits de Korotkoff sont produits par la vibration de la paroi artérielle sous l’impact de l’onde de pouls, puis par la turbulence de l’écoulement flux sanguin, et nous avons montré la diminution marquée de la vitesse locale de l’onde de pouls lorsque la pression du brassard réduit la pression artérielle transmurale. L’observation de ces enregistrements nous a montré l’intérêt de l’analyse de la forme de l’onde de pouls enregistrée par oscillométrie. Nous en avons tiré une approche innovante fondée sur l’analyse temporelle pour la détermination directe de la pression artérielle systolique. Nous avons réalisé une étude clinique prospective, selon un protocole approuvé par le Comité d’éthique du CHU de Nîmes, pour valider notre nouvelle approche. Nous avons comparé notre technique à la méthode auscultatoire chez 145 sujets avec ou sans facteurs de risque cardiovasculaire, et à la pression mesurée par cathéter radial chez 35 patients hospitalisés en réanimation. Nous avons obtenu une excellente concordance avec le premier bruit de Korotkoff, avec des résultats très supérieurs à l’oscillométrie réalisée à l’aide d’un appareil validé. De plus, notre technique s’est montrée capable d’identifier les sujets porteurs de facteurs de risque cardiovasculaires, se comparant favorablement à la vitesse de l’onde de pouls aortique. / Our thesis is devoted to the development of a new oscillometric signal analysis approach to measure systolic blood pressure and identify subjects with abnormal arterial wall rigidity. Oscillometry, widely used for the non-invasive automatic measurement of blood pressure, is based on the amplitude of the dynamic cuff-pressure oscillations generated by the expansion of the brachial artery at the arrival of the pulse wave.We first conducted a literature review on the auscultatory and oscillometric methods. The auscultatory method, based on the detection of the sounds emitted by the brachial artery under the cuff, remains the reference for the validation of oscillometric monitors. Since the description of these sounds by Nicolai Korotkoff in 1905, many authors attempted to explain their origin and assess their limits and pitfalls in comparison with direct intra-arterial blood pressure measurement.Oscillometric technique derive from the sphygmograph built by Etienne-Jules Marey in 1859. Manufacturers validate their oscillometric devices in reference to the international standards (ISO) without revealing the algorithms they use. Numerous approaches have been proposed, from fixed empirical ratios to neural networks to various mathematical models, for the calculation of systolic and diastolic pressure since only the mean arterial pressure is actually measured on the oscillometric curve. However, oscillometry yields variable results and produces significant errors, especially for systolic pressure, notably in patients with cardiovascular risk factors.Based on this analysis, and considering that the reference remains the detection of Korotkoff sounds, we sought to better understand their mechanisms. We recorded ultrasound images and the Doppler signal of the brachial artery under the cuff when measuring blood pressure in volunteers, simultaneously with ECG, cuff pressure and Korotkoff sounds. We could record the systolic diameter changes of the brachial artery during cuff deflation, and measure the local pulse wave velocity, as well as the time delay between the oscillometric signal, the ECG and the Korotkoff sounds. We were able to demonstrate that the Korotkoff sounds are produced by arterial wall vibration under the impact of the pulse wave, then by blood flow turbulence, and we measured the marked decrease in local pulse wave velocity when the cuff inflation reduces the brachial artery transmural pressure.We concluded to the interest of pulse waveform analysis, and designed an innovative approach based on its temporal characteristics for the direct determination of systolic blood pressure. We conducted a prospective clinical study, according to a protocol approved by the Ethics Committee of the Nîmes University Hospital Center, to validate our new approach. We compared our technique to the auscultation method in 145 subjects with or without cardiovascular risk factors, and to direct blood pressure measurement with a radial catheter in 35 patients hospitalized in the intensive care unit. We obtained an excellent correlation with the first Korotkoff sound, with better results than conventional oscillometry. In addition, our technique has proven able to identify subjects with cardiovascular risk factors with an accuracy favorably comparable to aortic pulse wave velocity.