Les pathologies cardiovasculaires sont le plus souvent l’aboutissement des processus liés à l’athérosclérose. Elles représentent la première cause de morbi-mortalité dans le monde et leur incidence s’accroit avec le vieillissement de la population et l’expansion de facteurs de risques comme le diabète ou l’obésité. La sténose valvulaire aortique (SVA) est la valvulopathie la plus fréquente dans les pays développés présentant de nombreux points communs avec l’athérosclérose vasculaire. En plus des facteurs de risque, les lésions valvulaires et les lésions vasculaires partagent des similitudes dans les processus physiopathologiques impliqués comme l’inflammation, la fibrose, l’angiogenèse et la calcification. Ce dernier processus apparait dans les stades avancés des pathologies liées à l’athérosclérose et joue un rôle critique via son implication dans la stabilité de la plaque ou l’épaississement des cuspides valvulaires aortiques. Les macrophages, cellules issues de la différenciation des monocytes infiltrés, jouent un rôle prépondérant dans ces lésions via les phénotypes classiques (M1) et alternatifs (M2). Néanmoins cette dichotomie ne reflète pas complètement la variété de leur plasticité et les différents phénotypes induits notamment par le microenvironnement des monocytes/macrophages (zones riches en lipides, zones riches en fer ou zones riches en calcification). Dans la valve aortique, les cellules interstitielles de valve (VIC) forment la population cellulaire la plus présente au sein de la valve aortique. Ces cellules jouent un rôle déterminant dans le maintien du tissu valvulaire, mais également dans les processus de calcification menant à la SVA. Dans un premier temps, cette thèse a pour but d’étudier la capacité des macrophages à former des ostéoclastes, cellules responsables de la dégradation de la matrice osseuse, au sein des plaques d’athérosclérose. Dans un second temps, ce travail se focalisera sur les processus de calcification de la valve aortique via l’étude du rôle de la leptine dans les calcifications valvulaires (étude a priori) puis dans une étude transcriptomique sans a priori de VIC issues de valve sténosées et non-sténosées. Nos résultats sur les macrophages montrent ex vivo que les cellules en bordure des calcifications vasculaires sont des macrophages alternatifs de type M2. In vitro, ces cellules sont incapables de se différencier en ostéoclastes et de résorber une matrice osseuse. Pour l’étude de l’effet de la leptine sur les VIC, nous montrons que la leptine sérique est plus élevée chez des patients présentant une SVA, nous confirmons que la leptine et son récepteur sont exprimés au sein des valves aortiques et que la leptine favorise la différenciation ostéoblastique des VIC de manière dépendante des voies Akt et ERK. Enfin, l’étude transcriptomique a permis de mettre en évidence une nouvelle voie métabolique dérégulée dans les VIC. Cette enzyme est sous exprimée dans les VIC issues de valves pathologiques et dans les zones calcifiées des valves aortiques sténosées. Par ailleurs, le traitement des VIC par le produit de cette enzyme en milieu procalcifiant inhibe la calcification. Cette thèse met en avant de nouveaux indices sur les processus de calcification observés dans les plaques d’athérosclérose et les valves aortiques sténosées. Ces résultats décrivent l’impossibilité des M2 à former des ostéoclastes capables de résorber les calcifications. Il sera intéressant d’étudier le phénotype des macrophages en bordure des calcifications des valves aortiques sténosées. D’autre part, il sera intéressant d’étudier l’origine de la leptine dans la valve et son mécanisme d’action sur les VIC. Enfin, ce travail a mis à jour une nouvelle voie métabolique, impliquée dans le développement des calcifications valvulaires, qui pourrait constituer une voie thérapeutique innovante dans le traitement médicamenteux de la SVA. / Cardiovascular diseases (CVD) are the most often outcome of atherosclerosis processes. CVD are the first leading cause of death rate with an increasing incidence due to ageing populations and expansion of risk factors such as diabetes mellitus or obesity. Aortic valve stenosis (AVS) is the most frequent valvulopathy in developed countries sharing common points with vascular atherosclerosis. More than only risk factors, valvular and vascular lesions share common pathophysiological processes implicated in the development of the disease such as inflammation, fibrosis, angiogenesis and calcification. This last process appears in late stages of atherosclerosis diseases and play critical roles via implication in plaque stability or thickening of the aortic valve. Macrophages are cells deriving from infiltrated monocytes, playing an important role in the inflammatory state of lesions via classical (M1) or alternative phenotypes (M2) phenotypes. Nevertheless, this dichotomy does not reflect completely the variety of their plasticity and different phenotypes induced by the microenvironment of monocytes/macrophages (lipid riche zone, iron riche zone or calcium rich zone). In the aortic valve, valvular interstitial cells (VIC) are the most prominent cell type found in the aortic valve. These cells play a major role not only in the valve tissue homeostasis but also in the calcification processes leading to AVS. In a first part, the aim of this thesis is to elucidate the ability of macrophages to differentiate into osteoclasts, cell type responsible for bone matrix remodeling, inside atherosclerosis plaques. In a second part, this work will focus on the calcification processes occurring in the aortic valve via the study of the role of leptin in valvular calcification (association study) and then in a transcriptomic analysis of VIC isolated from calcified versus non calcified aortic valves (genome-wide expression study). Our results about macrophages show that ex vivo cell surrounding vascular calcification are alternative M2 macrophages. In vitro, these cells are no able to differentiate into true osteoclasts nor to resorb calcium deposits. Concerning the role of leptin on VIC, the results show that serum leptin is higher in patients with AVS, leptin and its receptors are expressed in the aortic valves and leptin enhances the osteoblast différenciation of VIC in an Akt and ERK dependant manner. Finally, the transcriptomic analysis allowed to highlight a new pathway deregulated in VIC. This enzyme is underexpressed in VIC isolated from calcified aortic valves and in the calcified zonesAbstract4of stenosed aortic valves. Otherwise, treating VIC with the product of this enzyme in a procalcifying medium inhibits calcification processes.This thesis highlights new insights into the calcification processes occurring in atherosclerosis lesions and calcified aortic valves. These results describe that M2 macrophages cannot differentiate into osteoclasts and reverse calcification formation inside atherosclerosis plaques. In parallel, it would be interesting to study the macrophages phenotypes surrounding calcium deposits in stenosed aortic valves. Then, it will be interesting to decipher the origin of leptin and its precise mechanism of action on VIC. Finally this work points out a new metabolic pathway implicated in the development of valvular calcification which could be a medical treatment of SVA.

A hipertrofia cardíaca é uma adaptação do coração frente a estímulos de crescimento, sejam eles patológicos e irreversíveis como a sobrecarga de pressão ou de volume, ou fisiológicos e reversíveis como a gravidez e o exercício físico. A hipertrofia derivada de estímulos patológicos é conhecida como mal adaptativa enquanto que a hipertrofia proveniente de estímulos ditos fisiológicos é conhecida como benéfica ou adaptativa. Embora ambas hipertrofias tenham fatores em comum no que diz respeito ao crescimento do cardiomiócito e adaptações moleculares, elas acabam divergindo para desfechos completamente diferentes. A hipertrofia patológica evolui para um quadro de disfunção cardíaca ao passo que a hipertrofia fisiológica não acarreta nenhum dano funcional ao miocárdio. Essa linha tênue entre um fenótipo e outro envolve mecanismos celulares complexos que ainda precisam ser esclarecidos. Dentro deste cenário, os microRNAs aparecem como reguladores de diversos processos celulares, e têm sido associados ao crescimento miocárdico. Portanto, nosso objetivo foi comparar o padrão de expressão de microRNAs entre os modelos de hipertrofia fisiológica, induzido por natação (SWIM), e o modelo de hipertrofia patológica, induzida por bandeamento aórtico transtorácico (TAC). As análises foram realizadas após 28 dias para o modelo de natação, e 35 dias para o modelo de TAC. A comparação foi realizada através da técnica de microarranjo de microRNAs (Affymetrix). Interessantemente, apenas 20 microRNAs apresentaram níveis de expressão distinta entre os dois modelos de hipertrofia. Destes, 12 microRNAs apresentaram aumento de expressão (miR-193a-3p, miR-299a-5p, miR- 127-5p, miR-214-5p, miR-188-5p, miR-326-3p, miR-6395, miR-547-3p, miR-199a-5p, miR-381-3p, miR-223-3p e miR-199b-5p) e 8 estavam com seus níveis diminuídos (miR11 708-5p, miR-30c-1-3p, miR-22-5p, miR-6921-5p, miR-30a-3p, miR-30e-3p, miR-27a-5p and miR-6975-5p) no grupo TAC em relação ao grupo SWIM. Além disso, apenas 3 microRNAs, miR-21a-5p, miR-206-3p e miR-1983, apresentaram aumento de expressão tanto no grupo TAC quanto no grupo SWIM em comparação aos grupos SHAM e Sedentário, respectivamente. Após isso, foi realizada uma busca por possíveis alvos destes microRNAs na base de dados KEGG Pathway que identificou 4 rotas enriquecidas (665 genes) entre os alvos dos microRNAs reduzidos, e 80 rotas (3394 genes) fortemente associadas aos microRNAs que estavam aumentados no grupo TAC comparado ao SWIM. Conclui-se que existem microRNAs específicos para o desenvolvimento da hipertrofia cardíaca fisiológica, bem como patológica conforme os dados obtidos na análise de microarranjo. Além disso, os possíveis alvos destes microRNAs parecem estar envolvidos em rotas bastante envolvidas no crescimento celular, sobrevivência e adaptação cardíaca. / Cardiac hypertrophy is a heart adaptation in response to growth stimuli whether pathological and irreversible such as pressure overload or physiological and reversible as pregnancy and exercise. Hypertrophy because of pathological stimuli is known as mal adaptive while the one that comes from physiological triggers is known as beneficial or adaptive. Although both have similarities about cardiomyocyte growth and molecular adaptations, they diverge to distinct outcomes. The pathological hypertrophy evolves to a pattern of cardiac dysfunction while the physiological one does not cause any damage to the heart. This tenuous line between those phenotypes involves complex cellular mechanisms that need to be clarified. In this context, microRNAs are considered as regulators of many biological processes, and have been associated to myocardial growth. Therefore, our aim was to compare microRNA expression between physiological (swiminduced) and pathological (TAC-induced) hypertrophy. The analysis was performed after 28 days for SWIM protocol and 35 days for TAC model. The comparison was done using microRNA microarray technology (Affymetrix). Interestingly, only 20 microRNAs were differential expressed between both models. Out of those, 12 were up regulated (miR- 193a-3p, miR-299a-5p, miR-127-5p, miR-214-5p, miR-188-5p, miR-326-3p, miR-6395, miR-547-3p, miR-199a-5p, miR-381-3p, miR-223-3p and miR-199b-5p) while 8 were down regulated in TAC group compared to SWIM group. Besides, only 3 microRNAs, miR-21a-5p, miR-206-3p and miR-1983, were upregulated in TAC and SWIM model compared to SHAM and SED groups. After that, a search at KEGG Pathway database retrieved 4 pathways (665 genes) enriched with targets from microRNAs downregulated and 80 pathways (3394 genes) enriched with targets from up-regulated microRNAs in in 13 TAC group compared to SWIM group. In conclusion, there are microRNAs specific committed to the physiological cardiac hypertrophy development as well to the pathological cardiac growth as observed in our microarray data. Furthermore, the possible targets of those microRNAs could be involved in pathways associated with cellular growth, survival and cardiac adaptation.

O expressivo número de brasileiros que necessitam correção anatômica da estenose valvar aórtica acentuada e que não realizam cirurgia de substituição valvar devido ao risco proibitivo justifica a necessidade de investigação, tanto da efetividade no cenário clínico real quanto dos custos impostos ao Sistema Único de Saúde e aos planos de saúde suplementar brasileiros pela incorporação do implante transcateter de valva aórtica, que tem se demonstrado efetivo mas oneroso, internacionalmente. No primeiro artigo da tese, avaliaram-se os desfechos intra-hospitalares, a sobrevida e o reembolso pela internação hospitalar de 41 pacientes com idade média de 78,7 ± 6,3 anos, estenose valvar aórtica acentuada, com recusa cirúrgica e decisão multidisciplinar por tratamento transcateter entre outubro de 2010 e outubro de 2015. Os sujeitos foram seguidos prospectivamente por um período mediano de 15,2 (4,5 – 25,6) meses e a sobrevida estimada em 1 e 2 anos foi de 73,2% e 64,1%, respectivamente. Identificou-se que hipertensão pulmonar e revascularização miocárdica cirúrgica prévia estavam independentemente associadas à menor sobrevida. O valor mediano reembolsado pelos pacientes atendidos pelo Sistema Único de Saúde foi R$ 108.634,34 (101.051,05 – 127.255,27) e R$ 115.126,77 (94.603,21 – 132.603,01) para aqueles internados por planos de saúde suplementar ou particulares, sendo o respectivo valor mediano reembolsado pela prótese valvar de R$ 82.000,00 (82.000,00 – 95.450,00) e 84.050,00 (75.000,00 – 92.400,00) Em um grupo de 585 procedimentos de troca valvar aórtica cirúrgica em indivíduos com idade ≥ 60 anos, realizados entre janeiro de 2010 e dezembro de 2015 na mesma instituição, a mortalidade intra-hospitalar estava associada à idade e foi de 5,9% naqueles com idade entre 60 e 70 anos, 10,8% entre 70 e 80 anos e de 22,2% ≥ 80 anos. O reembolso mediano foi de R$ 14.035,96 (11.956,11 – 16.644,90) para os internados pelo Sistema único de Saúde e R$ 20.273,97 (15.358.03 – 32.815,49) pelos planos de saúde suplementar ou particulares. No segundo artigo da tese, identificou-se que do total de 819 pacientes consecutivamente incluídos no Registro Brasileiro de Implante de Bioprótese Aórtica por Cateter entre janeiro de 2008 e outubro de 2015, 15 (1,8%) sofreram perfuração do ventrículo esquerdo. Os pacientes que apresentaram perfuração eram mais idosos (85,4 ± 6,3 vs. 81,5 ± 7,3 anos, p=0,038), predominantemente mulheres (80,0% vs. 50,5%, p=0,024), apresentavam maior fração de ejeção (67,3 ± 7,8% vs. 58,6 ± 15,0%, p=0,001), menor massa ventricular esquerda (203,9 ± 47,1g vs. 247,6 ± 78,7g, p=0,039) e menor altura do tronco da coronária esquerda (11,2 ± 5,4mm vs. 14,0 ± 3,3mm, p=0,034). Os preditores independentes de perfuração do ventrículo esquerdo foram idade e fração de ejeção. No terceiro artigo, descreve-se um caso de ablação septal para tratamento de miocardiopatia hipertrófica obstrutiva assimétrica para posterior implante transcateter de valva aórtica, sugerindo que esta seja uma estratégia factível quando da concomitância dessas duas condições Em conclusão, os desfechos do tratamento transcateter da estenose valvar aórtica acentuada em pacientes inoperáveis são compatíveis com aqueles do cenário idealizado dos ensaios clínicos randomizados, apesar de estarem associados a custos maiores que os anteriormente estimados por painéis de especialistas. O tratamento cirúrgico, por sua vez, apresentou mortalidade maior que aquela idealizada ou relatada como usual. A hipercinesia do ventrículo esquerdo pode favorecer o trauma determinado pelo guia metálico, posicionado em seu interior para realização do procedimento, estando a fração de ejeção independentemente associada à chance de perfuração. Ainda, a ablação septal por álcool eletiva, anterior ao implante transcateter da valva aórtica, é uma abordagem factível para pacientes com hipertrofia ventricular esquerda assimétrica obstrutiva associada à estenose valvar aórtica. / The expressive number of Brazilians who require an anatomic correction for severe aortic valve stenosis and who do not undergo valvar replacement surgery due to prohibitive risk justifies the need to investigate both the effectiveness in the real clinical scenario and the costs imposed to the Public Health System and the Supplementary Health System for the incorporation of the transcatheter aortic valve implantation, which has been shown to be effective but onerous, internationally. In the first article of the thesis, the in-hospital outcomes, long-term survival and reimbursement for 41 patients, with a mean age of 78.7 ± 6.3 years, sever aortic valve stenosis, with surgical refusal and multidisciplinary decision for transcatheter treatment, between October 2010 and October 2015 are described. Subjects were prospectively followed for a median period of 15.2 (4.5 - 25.6) months and the estimated survival at 1 and 2 years was 73.2% and 64.1%, respectively. It was identified that pulmonary hypertension and previous coronary artery bypass grafting were independently associated with lower survival. Median reimbursed values by the Public Health System was R$ 108,634.34 (101,051.05 - 127,255.27) and by supplementary health plans was R$ 115,126.77 (94,603.21 - 132,603.01). The respective median values reimbursed for the valve prosthesis was R$ 82,000.00 (82,000.00 - 95,450.00) and 84,050.00 (75,000.00 - 92,400.00) In a group of 585 surgical aortic valve replacement procedures in subjects aged ≥ 60 years, performed between January 2010 and December 2015 in the same institution, in-hospital mortality was associated with age and was 5.9% in those with age between 60 and 70 years, 10.8% between 70 and 80 years and 22.2% in ≥ 80 years. The median reimbursement was R$ 14,035.96 (11,956.11 - 16,644.90) for those hospitalized by the Public Health System and R$ 20,273.97 (15,358.03 - 32,815.49) by supplementary or private health plans. In the second article of the thesis, it was identified that of the total of 819 patients consecutively included in the Brazilian Registry of Aortic Bioprosthesis Implantation by Catheter (RIBAC) between January 2008 and October 2015, 15 (1.8%) suffered perforation of the left ventricle. Patients with perforation were older (85.4 ± 6.3 vs. 81.5 ± 7.3 years, p=0.038), predominantly women (80.0% vs. 50.5%, p=0.024), had a higher ejection fraction (67.3 ± 7.8% vs. 58.6 ± 15.0%, p=0.001), lower left ventricular mass (203.9 ± 47.1g vs. 247.6 ± 78, 7g, p=0.039) and shorter distance between the aortic annulus and the left main coronary artery ostium (11.2 ± 5.4mm vs. 14.0 ± 3.3mm, p=0.034). The independent predictors of left ventricular perforation were age and ejection fraction. In the third article, a case of septal ablation was described for the treatment of asymmetric obstructive hypertrophic cardiomyopathy for posterior transcatheter aortic valve implantation, suggesting that this is a feasible strategy when these two conditions are concomitant In conclusion, the outcomes of transcatheter treatment of severe aortic stenosis in inoperable patients are compatible with those in the ideal scenario of randomized clinical trials, although they are associated with higher costs than previously estimated by expert panels. Surgical treatment, on the other hand, presented higher mortality than that idealized or reported as usual. The left ventricle hyperkinesia may favor the trauma determined by the metallic guide, positioned inside it to perform the procedure, the ejection fraction being independently associated with the chance of perforation. Furthermore, elective alcohol septal ablation, prior to transcatheter aortic valve implantation, is a feasible approach for patients with obstructive asymmetric left ventricular hypertrophy associated with aortic valve stenosis.

Introduction: Abdominal aortic aneurysms (AAA) have a prevalence of approximately 2%, and are more common in men. AAAs are generally asymptomatic, but if ruptured and untreated, the mortality rate is close to 100%. Screening programs for AAAs are implemented in Sweden, the UK, and the US. This study describes the different views of AAA screening with a special emphasis on underlying ethical issues. Aim: To analyze the scientific background of AAA screening in order to be able to discuss its ethical basis. Methods: This was a qualitative literature study with an analysis of arguments using a hermeneutic method. Articles were obtained through a literature search and consisted of official articles, scientific articles, and debate articles. Results: A recent dissertation has questioned the value of AAA screening because of decreased AAA mortality and risk for overdiagnosis. However, most studies and official recommendations are in favor of AAA screening because disease specific mortality decreases and the screening program is considered cost-effective. Conclusion: This study shows that intellectual passion has created an unusually polarized discussion. It seems that benefit outweighs harm. Since AAA screening is the first screening program which could lead to the death of a previously asymptomatic individual, well founded informed consent is extremely important. Finally, both decisions to act and not to act have moral consequences.

La sténose aortique (SA) est la maladie valvulaire cardiaque ayant la plus forte prévalence dans les pays occidentaux. On s’aperçoit que, malgré le respect des recommandations pour les indications opératoires, les patients présentent des évolutions très variables après chirurgie : certains patients restent symptomatiques, décèdent précocement, ou présentent une dysfonction ventriculaire gauche persistante. Il a été montré que les patients présentant à la fois une SA en bas débit (c’est-à-dire un volume d’éjection bas), une fraction d’éjection ventriculaire gauche (FEVG) altérée et un gradient de pression entre le ventricule et l’aorte abaissé avaient un pronostic péjoratif, avec un risque opératoire majoré lorsqu’ils subissaient un remplacement valvulaire chirurgical. Il a aussi été récemment démontré que, dans le contexte de la SA, un bas débit peut survenir alors que la FEVG est normale. Les objectifs généraux de ce doctorat sont d’étudier l’impact du débit (plus précisément le volume d’éjection ventriculaire gauche) sur le pronostic des patients atteints de SA, ainsi que l’évolution du débit après intervention et les déterminants de son évolution. Les résultats indiquent que le volume d’éjection ventriculaire gauche, que ce soit avant intervention, ou son évolution après TAVI (Transcatheter Aortic Valve Implantation), sont des prédicteurs indépendants puissants de mortalité chez ces patients. / Aortic stenosis (AS) is the most common valvular heart disease in occidental countries. Despite proper use of the guidelines, some patients can present adverse outcomes after surgery: some of them remain symptomatic, some die prematurely, or suffer from a persistant left ventricular dysfunction. It has been demonstrated that patients presenting an AS with low flow (i.e. low stroke volume), impaired left ventricular ejection fraction (LVEF), and a low transvalvular mean gradient, have poor prognosis, with increased risk during aortic valve replacement surgery. It has also been demonstrated that, in AS, a low flow can occur despite a preserved LVEF. The main goals of this PhD were to evaluate the impact of flow (more precisely left ventricular stroke volume) on the prognosis of patients with AS, the evolution of flow after intervention, and the factors that influence it. The results show that left ventricular stroke volume, before or after intervention, or its evolution after TAVI (Transcatheter Aortic Valve Implantation), are powerful independant predictors of mortality.

O objetivo do presente trabalho foi avaliar a morfologia e a ultraestrutura da hiperplasia intimal arterial decorrente de um modelo de estenose aórtica experimental, através da inserção de um pino de acrílico no orifício da artéria renal esquerda. Realizamos um estudo morfológico e ultraestrutural em 64 ratos Wistar, machos, com peso médio de 250 g, divididos em 4 subgrupos de acordo com o dia da eutanásia (1, 7, 15 e 30 dias de pós-operatório). O segmento da aorta envolvendo o pino foi retirado e estudado com diferentes protocolos para: microscopia óptica de alta resolução, microscopia eletrônica de transmissão e de varredura. Uma trombose se formou ao redor do pino 24 horas após a cirurgia, mostrando sinais de organização com 7 dias. Com 15 dias, uma hiperplasia intimal adjacente à base do pino foi visualizada. Esta alteração permaneceu com 30 dias de pós-operatório. Este espessamento era caracterizado principalmente por células musculares lisas provenientes da camada muscular média. A obstrução gera alterações hemodinâmicas locais com repercussão sobre as células endoteliais localizadas próximas à base do pino. Esses achados são discutidos. / Objective: To study the light and electron microscopy of intimal hyperplasia induced by experimental aortic stenosis after insertion of a plug into the aorta through the left renal artery. Methods: Sixty-four Wistar male rats, weighing an average of 250g, were allocated into two groups: group control, sham-operated, and group experimental, operated. The animals were killed on days 1, 7, 15, and 30 after surgery. The fragments of aorta implicating the plug were excised and studied using high resolution light microcopy and transmission and scanning electron microscopy. Results and Conclusions: A thrombus was observed around the plug 24 hours after surgery, organized at day 7. An intimal hyperplasia could be observed closed to the basis of the plug 15 and 30 days after surgery. The intimal thickening detected was mainly composed of smooth muscle cells migrated from the medial layer of the aorta intermixed with extracellular matrix. Moreover, the endothelial cells around the plug lost their orientation. Theses findings are discussed.

Vascular calcification is a prominent cardiovascular condition found worldwide. This condition is predominantly found in the elderly population, and patients who suffer from chronic kidney disease, due to an imbalance of serum phosphate and calcium levels. For many years, vascular calcification was believed to be a passive pathological process which develops with ageing and/or lifestyle. Little has been documented about the disease until the 20th century, when interest in cardiovascular research grew amongst scientists. Indeed, vascular calcification underpins severe clinical outcomes and cardiovascular diseases have been labelled the global leading cause of death. Calcific aortic valve diseases (CAVD) is a progressive degenerative condition characterised by the development of lipo-calcification around the aortic valve leaflets leading to severe aortic stenosis and aortic regurgitation, which may ultimately lead to heart failure. At present there are no pharmaceutical therapies that can stop its progression and its molecular mechanisms are not fully understood. Recent findings have suggested that vascular smooth muscle cell (VSMC) calcification shares many common features with physiological skeletogenesis via the release of matrix vesicles (MVs), which are specialised structures that initiate mineralisation during bone formation. The ability for MVs to nucleate calcium and phosphate highly depend on their protein composition, as this may vary depending on active cell signalling and the microenvironment. This mechanism involving MV-regulated calcification has yet to be examined in CAVD. In this study, examined whether calcium and/or phosphate regulate VIC-derived MVs to induce calcification in the aortic valve. I used a primary rat valve interstitial cell (VIC) model, coupled with stenotic human valve tissues to characterise and study the mechanisms underpinning CAVD. X-ray fluorescence and diffraction analysis showed the mineral found in calcified human aortic valves to be hydroxyapatite (HA), the main component in bone. Additional imaging studies employing transmission electron microscopy (TEM) revealed particles that were similar in size and morphology to skeletal MVs. To further characterise VIC-derived MVs in vitro, I harvested MVs from rat VICs, and subsequently studied their protein composition using Isobaric tag for relative and absolute quantitation (iTRAQ) mass spectrometry. The data obtained from the proteomics analysis was compared to previous published studies on MV proteins derived from osteoblasts and VSMCs. The results showed the upregulation of numerous calcification regulators in MVs isolated from all 3 cell types, in particular, the Annexin family, which are known calcium binding proteins. Further studies conducted with Annexin 6, an established calcium regulator in arterial calcification, revealed its colocalisation with MV-enriched areas in calcified human aortic valve tissue suggesting it may play an important role in calcium regulation during CAVD.

Background: Women are more likely to develop age-related cognitive impairment compared with men of the same age. Pregnancy complications, such as preeclampsia (PE), and menopause may contribute to an elevated risk of cognitive decline with aging in women potentially through an adverse impact on vascular function. PE is associated with a heightened risk of hypertension and large elastic artery stiffness (i.e., aortic and carotid arteries) for several years postpartum. Persistent large artery stiffness may be further amplified in women with a history of PE during the menopause transition, which is marked by an accelerated rate of vascular aging. However, large artery stiffness has not been studied extensively in postmenopausal women with a history of PE. Age-related elevations in large artery stiffness are associated with cognitive decline in middle-aged and older adults however, this relation has not been investigated in young women with a history of PE. Moreover, the degree to which elevated large artery stiffness is amplified and associated with reduced cognitive function among postmenopausal women with a history of PE remains unknown. The purpose of this study was to examine the extent to which large elastic artery stiffness is associated with reductions in cognitive function in premenopausal and postmenopausal women with a history of PE. Methods: Large elastic artery stiffness and domains of cognitive function were assessed in young women one year postpartum (n=18, ages 24-41 yrs.) and postmenopausal women (n=19, ages 52-77 yrs.) thirty-five years postpartum. Aortic stiffness was measured via non-invasive applanation tonometry at the carotid and femoral pulse sites and expressed as carotid-femoral pulse wave velocity (cfPWV). Carotid artery stiffness was quantified as beta-stiffness index (β-stiffness) was measured via ultrasonography and carotid tonometry. Cognitive tests were administered to assess cognitive function in immediate and delayed recall, working memory, processing speed, and executive function. Results: Premenopausal women with a history of PE had higher systolic blood pressure (121 ± 4 vs. 101 ± 3 mmHg, p =0.01) one year postpartum but did not differ significantly from controls in cfPWV (6.2 ± 0.4 vs. 5.1 ± 0.2 m/s, p =0.08), β-stiffness (6.1 ± 0.5 vs. 6.1 ± 0.7 U, p =0.97), or cognitive domains of memory, executive function, or processing speed (all p>0.05). Higher systolic blood pressure was associated with lower executive function (r = -0.53, p = 0.05) in young women one year postpartum. Postmenopausal women with a history of PE did not differ from controls in blood pressure, large artery stiffness, or age-adjusted cognitive domains of memory, executive function, or processing speed (all p>0.05). Large artery stiffness was not associated with cognitive function in premenopausal or postmenopausal women. Conclusions: Young women with a history of PE had elevated systolic pressure one year postpartum, which was associated with reductions in executive function. Large artery stiffness was not elevated or related to cognitive function in postmenopausal women with a history of PE. These preliminary findings suggest that young women with a history of PE are susceptible to reductions in selective cognitive domains related to higher blood pressure, but this effect does not appear to extend into the postmenopausal period.

Abdominal aortic aneurysms (AAAs), a permanent dilation in the abdominal region of the aorta, is a highly sexually dimorphic disease. AAAs prevalence is ranging from 4-10 fold higher in males than females. Defining the mechanistic basis for reduced (in females) or increased (in males) AAA formation and progression may uncover potential therapeutic targets. The majority of studies examining sexual dimorphism focus on the role of sex hormones. However, genes residing on sex chromosomes, in addition to sex hormones, may contribute to sexual dimorphism of AAAs. For example, the X chromosome contains about 5% of the whole genome, but the role of sex chromosomes genes to sexual dimorphism of cardiovascular diseases such as AAAs is largely unknown. The purpose of this study was to determine the role of sex chromosomes as mediators of sex differences for angiotensin II (AngII)-induced AAAs in hypercholesterolemic mice. We used the four core genotype murine model, which enables the creation of phenotypically normal male and female mice with an XX versus XY sex chromosome complement, to test the hypothesis that an XY sex chromosome complement promotes AngII-induced AAAs. Transgenic male mice expressing the Sry gene on an autosome, but not on the Y-chromosome, were bred to female low-density lipoprotein receptor deficient mice to create male and female mice with an XX or an XY sex chromosome complement. In females, an XY sex chromosome complement doubled the incidence and markedly increased the severity of AngII-induced AAAs. To define mechanisms, we examined gene expression patterns in abdominal aortas and demonstrated elevated expression of inflammatory genes that were linked to increased MMP activity and oxidative stress in aortas from XY females. Moreover, administration of testosterone to XY females, to mimic males, resulted in a striking level of aneurysm rupture. In males, transcriptional profiling of abdominal aortas revealed 450 genes that were influenced by sex chromosomes. Infusion of AngII to XY males resulted in diffuse pathology along the length of the aorta, while XX males developed focal AAAs, with pathology reduced by orchiectomy in both genotypes. Thoracic aortas of XY males exhibited adventitial thickening which was not exist in thoracic aortas from XX males. Following a prolonged period (3 months) of AngII infusions XY males had AAAs with expanded aortic walls, while XX males had thin walled dilated AAAs. In summary, our findings demonstrate a remarkable effect of sex chromosome complement to regulate aortic vasculature and disease development. Aside from demonstrating mechanisms of sexual dimorphism of aortic diseases, these findings indicate that chronic sex hormone therapy in the aging and transgender population may have cardiovascular ramifications. Moreover, identification of targets influenced by sex chromosomes and/or sex hormones in a manner that predicts disease development may identify sex-specific approaches to cardiovascular therapy.

Le rétrécissement aortique (RAo) est la valvulopathie la plus fréquente dans les pays industrialisés. Il entraine une augmentation chronique de la postcharge imposée au ventricule gauche (VG) se caractérisant par une hypertrophie ventriculaire gauche (HVG), une ischémie et une fibrose myocardique, une dysfonction diastolique et à long terme une insuffisance cardiaque. Indépendamment de la sévérité de la valvulopathie, plusieurs facteurs comme l’obésité, le diabète, l’insulinorésistance semblent influencer le remodelage ventriculaire dans cette condition. Ces troubles métaboliques sont associés à un état pro-inflammatoire, notamment du tissu adipeux, impliquant des médiateurs également associés à l’hypertrophie cardiomyocytaire et la fibrose myocardique. A l’heure actuelle, le remplacement valvulaire aortique (RVAo) chirurgical est le seul traitement ayant montré son impact sur la diminution de la morbi mortalité dans le RAo. Cette chirurgie est devenue peu risquée de nos jours et permet une diminution conséquente de la masse ventriculaire gauche (MVG) dans la première année. Néanmoins certains facteurs, en particulier un remodelage important en préopératoire et l’existence d’un mismatch patient-prothèse (PPM), semblent influencer le remodelage inverse après la chirurgie pouvant expliquer la persistance d’une fibrose myocardique ou de symptômes après l’opération. Nous avons émis les hypothèses suivantes : a) un état pro inflammatoire médié par le tissu adipeux épicardique (TAE) et les leucocytes circulants serait associé à un remodelage pathologique dans l’histoire naturelle du RAo, b) l’existence d’un PPM après RVAo serait associé à un moins bon pronostic indépendamment du poids corporel, c) l’horloge biologique jouerait un rôle dans la modulation de la réponse myocardique à un stimulus hypertrophique et à l’ischémie myocardique, d) l’apparition d’une dysfonction ventriculaire droite (VD) postopératoire, serait associée à un mauvais pronostic après RVAo. Nous avons donc inclus prospectivement les patients porteurs d’un RAo serré sans dysfonction VG, sans autre valvulopathie, adressés depuis 2009 au Centre des Valvulopathies du CHRU de Lille pour un premier RVAo. Une évaluation clinique, biologique ainsi qu’une échocardiographie transthoracique (ETT) pré et postopératoire (avant la sortie) ont été réalisées. Pour une partie de la population, différents prélèvements biologiques (sang et TAE) ont été effectués au moment du bloc opératoire afin de réaliser des analyses de transcriptomique sur le TAE et de cytométrie en flux sur les cellules sanguines circulantes. Une partie de la population a également été revue en ETT à 1 an et tous les patients ont été suivis à distance. Nous avons pu montrer que : a) la quantité de TAE était indépendamment associée à un remodelage VG plus sévère dans le RAo mais n’était pas associée à l’importance du remodelage inverse après RVAo. D’après nos premiers résultats, ce remodelage VG plus sévère semble associé à une dysrégulation de gènes impliqués dans la réponse immunitaire adaptative, dans la régulation de la réponse immunitaire et dans l’activation des cellules lymphocytaires T et également à un nombre de leucocytes et de monocytes circulants plus important, b) une surface fonctionnelle indexée de la prothèse aortique implantée lors du RVAo de moins de 0,85 cm²/m² était le paramètre valvulaire le plus puissant pour prédire les évènements cardiovasculaires à distance de l’opération chez les patients non obèses. De manière surprenante, chez les patients obèses aucune association n’était retrouvée entre cette surface fonctionnelle et le devenir des patients après RVAo, c) il existe une variation circadienne de la tolérance à l’ischémie-reperfusion imposée lors du RVAo [...] / Aortic stenosis (AS) is the most common valvular heart disease (VHD) in Western countries. It causes a chronic increase in left ventricular (LV) afterload characterized by left ventricular hypertrophy (LVH), ischemia and myocardial fibrosis, diastolic dysfunction and long-term heart failure. Regardless of the severity of stenosis, several factors such as obesity, diabetes, insulin resistance seems to impact the LV remodeling in this condition. These metabolic disorders are associated with a pro-inflammatory state, including adipose tissue, involving mediators perceived in cardiomyocyte hypertrophy and myocardial fibrosis. To date, surgical aortic valve replacement (SAVR) is the only option that has shown an impact on mortality. This surgery has become less risky and leads to a significant decrease in the left ventricular mass (LVM) in the first year. Nevertheless, some factors, including the existence of a patient-prosthesis mismatch (PPM), seem to influence this reverse remodeling after surgery, which may explain the persistence of myocardial fibrosis or symptoms after the surgery. We have made the following hypotheses: a) a pro-inflammatory state mediated by epicardial adipose tissue (EAT) and circulating leukocytes would be associated with pathological remodeling in the natural history of AS, b) the existence of a PPM after SAVR would be associated with a poorer prognosis regardless of body weight status, c) the circadian clock would play a role in modulating the myocardial response to a hypertrophic stimulus and myocardial ischemia, d) the onset of postoperative right ventricular (RV) dysfunction, would be associated with poorer prognosis after SAVR. We therefore prospectively included patients with severe AS without LV dysfunction, or another VHD, referred to our Heart Valve Center in Lille University Hospital since 2009 for a first SAVR. Clinical and biological evaluation and pre- and postoperative (before discharge) trans-thoracic echocardiography (TTE) were performed for all patients. In a sub-group of patients, biological samples (blood and TAE) were collected at the time of surgery to perform transcriptomic analysis on EAT and flow cytometry on the circulating blood cells. TTE was also performed 1-year after SAVR in a sub-group and all patients were followed-up for cardiovascular events. We found that: a) the amount of EAT was independently associated with worse LV remodeling in AS but not with the magnitude of reverse remodeling after SAVR. According to our first results, this more severe LV remodeling seems to be associated with dysregulation of genes involved in the adaptive immune response, in the regulation of the immune response and in the activation of T lymphocyte cells and also with a number of circulating leukocytes and monocytes more important, b) the indexed effective orifice area of the aortic prosthesis calculated by TTE with the unique cut-off of 0.85cm²/m² showed the best accuracy to predict major events after SAVR in lean or overweight patients but not in obese, c) perioperative myocardial injury is transcriptionally orchestrated by the circadian clock in patients undergoing SAVR, with poorer tolerance in patients operated on in the morning, d) heart failure is more frequently observed in patients operated on in the morning, unrelated to the occurrence of acute kidney injury after SAVR, e) the early and severe post-operative decline in RV longitudinal function reverses within a year and is not predictive of long-term outcomes after SAVR. Subsequently, we will continue to explore the link between adipose tissue and the natural course of LV remodeling, cardiovascular events after SAVR in particular the impact of circadian variations on the occurrence of heart failure and the RV function after SAVR.