Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / O desenvolvimento da programação fetal é considerado um importante fator de risco para doenças não-transmissíveis da vida adulta, incluindo doença cardíaca coronariana. Com o objetivo de investigar a associação entre nutrição materna e o desenvolvimento das artérias coronárias (AC) em embriões de camundongos estadiados; embriões de camundongos C57BL/6 nos estádios de 16-23 foram retirados de mães alimentadas com dietas de proteína normal (NP) ou de baixa proteína (LP), e as AC foram estudadas. Embora os embriões LP possuam massa corporal menor, entretanto tinham taxas de crescimento cardíaco maior, quando comparados com os embriões NP. O Plexo subepicárdico foi observado no início do período pós-somítico (estádio 16) de embriões NP, enquanto que nos embriões LP apenas no estádio 17 (P <0,01), persistindo até o estádio 18 (P <0,01). As artérias coronárias foram detectadas inicialmente no estádio18 dos embriões NP, já nos embriões LP foram encontradas a partir do estádio 19 (P <0,01). Núcleos apoptóticos foram observados em torno do anel aórtico peritruncal no estádio 18 em embriões NP e LP. Células FLK1+ (Fetal Liver Kinase 1 = VEGFr2 = Vascular Endothelial Growth Factor Receptor 2) apresentaram uma distribuição homogênea nos embriões NP já no estádio 18, enquanto uma distribuição semelhante nos embriões LP foi visto apenas nos estádios 22 e 23. A restrição proteica materna em camundongos leva a um atraso no crescimento do coração no período embrionário modificando o desenvolvimento do plexo peritruncal subepicárdica e diminuindo a taxa de apoptose na região do futuro orifício coronariano. / Programming of fetal development is considered to be an important risk factor for non-communicable diseases of adulthood, including coronary heart disease (CHD). Aiming to investigate the association between maternal nutrition and the development of the coronary arteries (CA) in staged mice embryos, C57BL/6 mice embryos from stages 16 to 23 were taken from mothers fed a normal protein (NP) or low protein (LP) diet, and the CA were studied. Although the LP embryos had lower masses, they had faster heart growth rates when compared to the NP embryos. The subepicardial plexuses were observed earlier in the NP embryos (stage 20) than in the LP ones (stage 22) (P<0.01). Apoptotic nuclei were seen around the aortic peritruncal ring beginning at stage 18 in the NP and LP embryos. FLK1+ (fetal liver kinase 1 = VEGFr2 or vascular endothelial growth factor receptor 2) cells had a homogeneous distribution in the NP embryos as early as stage 18, whereas a similar distribution in the LP embryos was only seen at stages 22 and 23. Maternal protein restriction in mice leads to a delay in the growth of the heart in the embryonic period modifying the development of the subepicardial peritruncal plexus and the apoptosis in the future coronary orifice region.

Short summary: Background: High cardiovascular risk in patients with chronic kidney disease is partly due to mineral dysbalance, microinflammation and oxidative stress. CKD patients accumulate traditional and non-traditional CV risk factors. FGF23, MMPs and PlGF belong among these non-traditional biomarkers of CV risk. FGF23 is a phosphaturic hormone and inhibitor of calcitriol synthesis. It is associated with vascular calcifications. Matrix-metalloproteinases (e.g. MMP-2, MMP-9) are proteolytic, proinflammatory enzymes, contributing to myocardial remodelation. Placental growth factor (PlGF) is a proangiogenic cytokine that is associated with LV hypertrophy in animal model. Plasmatic FGF23, MMPs and PlGF are elevated in CKD. Aim: We aimed to describe dynamic changes between several novel biomarkers of CV risk (FGF23, MMP-2, MMP-9 and PlGF) in CKD stages 1-5, to describe their mutual correlations and possible association with traditional CV risk markers. We studied possible association of laboratory and echocardiographic parameters in patients with CKD stages 2-4. Methods: In a cross-sectional study we evaluated 80 patiens with CKD 1-5 and 44 healthy controls. In a prospective study we evaluated echocardiographic and laboratory parameters in 62 patients with CKD 2-4 for an average study period of 36±10...

Au cours du vieillissement, la rigidification des artères élastiques entraine une augmentation de l'amplitude de la pression pulsée centrale, qui se propage dans la microcirculation cérébrale. De façon chronique, l’élévation anormale de la pression pulsée endommage les fonctions vasculaires et cérébrales, pouvant être impliquée dans le développement d’une déficience cognitive d’origine vasculaire. Ceci est supporté par l’observation d’anomalies cérébrovasculaires chez les individus atteints de démence vasculaire et de la maladie d’Alzheimer. De plus, les individus exposés aux facteurs de risque vasculaires (hypertension, obésité, diabète, athérosclérose), démontrent une vascularisation fragilisée, une augmentation de la pression pulsée centrale et présentent un déclin cognitif. Il est donc probable qu’en association avec l’âge, les facteurs de risque vasculaires favorisent de façon mécanistique la propagation de la pression pulsée dans la circulation cérébrale et révèlent de façon prématurée le déclin cognitif. Le lien mécanistique entre l’augmentation de la pression pulsée cérébrale, les facteurs de risque vasculaires, les dommages cérébrovasculaires et l’incidence de la démence reste à être plus clairement investigué. La présente thèse vise ainsi à étudier l’hypothèse biomécanique du rôle délétère de la pression pulsée dans la détérioration des fonctions cérébrovasculaires et cognitives, avec l’âge et en association avec les facteurs de risque vasculaires, en élucidant la cascade des événements pathologiques depuis l’élévation de la pression pulsée centrale jusqu’à l’incidence de la démence. Afin de vérifier notre hypothèse, nous avons entrepris dans une première étude d’étudier chez la souris WT, l’impact de l’augmentation in vivo d’un stress mécanique pulsatile central (par chirurgie TAC) sur la vasculature cérébrale, le tissu cérébral et les fonctions cognitives. Ce stress a été induit en parallèle dans le modèle de souris transgénique APP/PS1 de la maladie d’Alzheimer. Nous avons pu démontrer que les vaisseaux cérébraux des souris WT et APP/PS1 sont vulnérables au stress mécanique de la pression pulsée, caractérisé par une diminution de la réponse vasodilatatrice des artères piales, une raréfaction des capillaires due à une apoptose, l’incidence de micro-hémorragies, une rupture de la barrière hémato-encéphalique et une hypoperfusion cérébrale. Ces dommages cumulatifs à la microcirculation cérébrale sont associés à une inflammation cérébrale et à une diminution des performances d’apprentissage et de mémoire de travail et spatiale des souris. De plus, le phénotype Alzheimer des souris APP/PS1 est exacerbé en présence du stress vasculaire, exprimé par l’augmentation des dépôts béta-amyloïdes, ainsi que la dysfonction endothéliale cérébrale et l’inflammation cérébrale déjà présentes dans ce modèle. Dans une deuxième étude, nous avons caractérisé les fonctions cérébrovasculaires et cognitives des souris transgéniques LDLR-/-;hApoB100+/+ avec l’ajout ou non d’un stress mécanique pulsatile central in vivo (par chirurgie TAC). Ces souris présentent des facteurs de risques des maladies cardiovasculaires (hypertension et dyslipidémie) menant au développement d’athérosclérose et miment un vieillissement artériel central accéléré (rigidité aortique et des carotides, dysfonction endothéliale, augmentation de la pression pulsée). Nous avons démontré que les souris LDLR-/-;hApoB100+/+ exhibent des anomalies cérébrovasculaires structurelles et fonctionnelles, dont une atrophie cérébrale, une dysfonction endothéliale cérébrale, une hypoperfusion cérébrale, une augmentation de la perméabilité de la barrière hémato-encéphalique, des micro-hémorragies corticales, la présence d’inflammation, de sénescence et de stress oxydant au niveau vasculaire et parenchymateux. L’ensemble de ces altérations majoritairement vasculaires, sont associées à une diminution des performances cognitives et sont exacerbées en présence d’un stress vasculaire additif. Nos deux études chez la souris démontrent qu’en présence d’une pression pulsée élevée, les dommages à la microvasculature cérébrale conduisent à une perte fonctionnelle de l’homéostasie cérébrale et à un déclin cognitif, dont l’incidence est accélérée soit dans un modèle de démence ou soit de vieillissement artériel central et en présence de facteurs de risque des maladies cardiovasculaires. Nos études fournissent la démonstration mécanistique d’un continuum entre une augmentation de pression pulsée et un déclin cognitif vasculaire. / With advancing age, the large elastic arteries undergo significant stiffening, resulting in increased central pulse pressure waves that penetrates deeper the cerebral microcirculation and may result in cerebrovascular and neuronal tissue damages, likely contributing to the development of cognitive impairment from vascular injury origin. This is compatible with strong evidence between impaired cerebrovascular structure and function in the brain of patients with vascular dementia or Alzheimer’s disease. In addition, elderly individuals are subjected in their lifetime to multiple vascular risk factors (hypertension, obesity, diabetes, atherosclerosis), all of which are known to be deleterious to the vascular function, are associated with an increase in central pulse pressure and with cognitive decline. Therefore, it is likely that with age, risk factors for vascular diseases may mechanistically promote the propagation of pulse pressure into the cerebrovascular system and reveal prematurely the brain susceptibility to cognitive decline. The present thesis was conducted to study the biomechanical hypothesis of the deleterious role of the pulse pressure in the deterioration of cerebrovascular and cognitive functions, with age and in association with vascular risk factors, by elucidating the cascade of pathological events linking the increase in central pulse pressure to the expression of dementia. To validate our hypothesis, we first studied in mice the impact of the in vivo increase of central pulsatile mechanical stress (achieved by trans-aortic constriction surgery) on the cerebral vasculature, brain tissue and cognitive functions. This stress was also induced in the APP/PS1 transgenic mouse model of Alzheimer's disease. We have shown that cerebral vessels of WT and APP/PS1 mice are vulnerable to the mechanical stress of the increased pulse pressure, which is characterized by a decrease in the vasodilatory response of the pial arteries, a rarefaction of the capillaries due to apoptosis, the incidence of micro-hemorrhages, a rupture of the blood-brain barrier and cerebral hypoperfusion. These cumulative damages to the cerebral microcirculation are associated with brain inflammation and poorer learning and working and spatial memory performances in mice. The Alzheimer's phenotype of APP/PS1 mice was exacerbated in the presence of elevated pulse pressure, as shown by the increase in beta-amyloid deposits, the decreased in endothelial cerebral vasodilatory responses and brain inflammation, which are already present in this model. In a second study, we sought to characterize the cerebrovascular and cognitive functions in the transgenic mouse model LDLR-/-;hApoB100+/+, subjected or not in vivo to a central pulsatile mechanical stress (by trans-aortic constriction surgery). These mice exhibit risk factors for cardiovascular diseases (hypertension and dyslipidemia), develop atherosclerosis and mimic premature central arterial aging (aortic and carotid stiffness, endothelial dysfunction, increased pulse pressure). We reported that LDLR-/-;hApoB100+/+ mice were characterized by structural and functional brain vascular abnormalities, including cerebral hypoperfusion, increased permeability of the blood-brain barrier, endothelial cerebral dysfunction, microhemorrhages, but also cerebral atrophy and the presence of inflammation, senescence and high oxidative stress at the vascular and parenchymal level. In addition, all these alterations, which are mainly vascular, were associated with a decrease in the cognitive performance of mice. Also, these vascular, parenchymal and cognitive changes were exacerbated in the presence of the vascular stress induced by transverse aortic constriction. Altogether, our two studies in mice demonstrated that, in the presence of an increase in pulse pressure, the damages to the micro-cerebrovascular system lead to loss of cerebral homeostasis and to cognitive decline, which are accelerated in a model of dementia or a model of central vascular aging and in presence or vascular risk factors. Our studies highlight the mechanistic demonstration of a continuum between an increase in pulse pressure and vascular cognitive decline.

Short summary: Background: High cardiovascular risk in patients with chronic kidney disease is partly due to mineral dysbalance, microinflammation and oxidative stress. CKD patients accumulate traditional and non-traditional CV risk factors. FGF23, MMPs and PlGF belong among these non-traditional biomarkers of CV risk. FGF23 is a phosphaturic hormone and inhibitor of calcitriol synthesis. It is associated with vascular calcifications. Matrix-metalloproteinases (e.g. MMP-2, MMP-9) are proteolytic, proinflammatory enzymes, contributing to myocardial remodelation. Placental growth factor (PlGF) is a proangiogenic cytokine that is associated with LV hypertrophy in animal model. Plasmatic FGF23, MMPs and PlGF are elevated in CKD. Aim: We aimed to describe dynamic changes between several novel biomarkers of CV risk (FGF23, MMP-2, MMP-9 and PlGF) in CKD stages 1-5, to describe their mutual correlations and possible association with traditional CV risk markers. We studied possible association of laboratory and echocardiographic parameters in patients with CKD stages 2-4. Methods: In a cross-sectional study we evaluated 80 patiens with CKD 1-5 and 44 healthy controls. In a prospective study we evaluated echocardiographic and laboratory parameters in 62 patients with CKD 2-4 for an average study period of 36±10...

Chronic kidney disease (CKD) and acute kidney injury (AKI) are major public health problems. It is important to be able to identify those at high risk of adverse outcome, CKD progression and associated cardiovascular disease. The aim of the thesis was to study novel promising biomarkers, their relationship to kidney function, chronic inflammation and/or cardiovascular risk - placental growth factor (PlGF), pregnancy associated plasma protein A (PAPP-A), matrix metalloproteinase 2 (MMP-2), matrix metalloproteinase 9 (MMP-9), soluble receptor for advanced glycation end products (sRAGE), calcium binding protein S100A12 or extracellular newly identified RAGE binding protein (EN-RAGE), and high mobility group box protein-1 (HMGB-1) in patients with renal diseases including CKD, haemodialysis (HD), AKI patients, and healthy controls for comparison. First study revealed that PlGF is elevated in patients with decreased renal function. Second study demonstrated the association of MMP-2 and PAPP-A with proteinuria in patients with CKD. Moreover, serum MMP-2, MMP-9 and PAPP-A levels significantly differed in patients with various nephropathies. EN-RAGE levels are not elevated in patients with CKD, but are related to inflammatory status. PAPP-A, EN-RAGE and HMGB-1 levels are significantly elevated, but sRAGE and PlGF...

Chronic kidney disease (CKD) and acute kidney injury (AKI) are major public health problems. It is important to be able to identify those at high risk of adverse outcome, CKD progression and associated cardiovascular disease. The aim of the thesis was to study novel promising biomarkers, their relationship to kidney function, chronic inflammation and/or cardiovascular risk - placental growth factor (PlGF), pregnancy associated plasma protein A (PAPP-A), matrix metalloproteinase 2 (MMP-2), matrix metalloproteinase 9 (MMP-9), soluble receptor for advanced glycation end products (sRAGE), calcium binding protein S100A12 or extracellular newly identified RAGE binding protein (EN-RAGE), and high mobility group box protein-1 (HMGB-1) in patients with renal diseases including CKD, haemodialysis (HD), AKI patients, and healthy controls for comparison. First study revealed that PlGF is elevated in patients with decreased renal function. Second study demonstrated the association of MMP-2 and PAPP-A with proteinuria in patients with CKD. Moreover, serum MMP-2, MMP-9 and PAPP-A levels significantly differed in patients with various nephropathies. EN-RAGE levels are not elevated in patients with CKD, but are related to inflammatory status. PAPP-A, EN-RAGE and HMGB-1 levels are significantly elevated, but sRAGE and PlGF...