Atualmente, temos a disposição modernas técnicas de mapeamento eletroanatômico gerando imagens tridimensionais da propagação do impulso nas câmaras cardíacas através de catéteres endocavitários. Apesar disso, poucos estudos estão disponíveis a respeito do mapeamento eletrofisiológico epicárdico. A avaliação intraoperatória de contratilidade miocárdica imediatamente após a revascularização miocárdica é visual e Ecocardiográfica, porém este é muito pouco utilizado para este fim. Há, portanto, a necessidade de desenvolvimento de novos métodos capazes de avaliar o impacto funcional da revascularização miocárdica. Objetivo: Avaliar a resposta intra-operatória de contratilidade miocárdica regional mediante o mapeamento epicárdico com eletrodo decapolar. Métodos: 20 pacientes serão submetidos a revascularização miocárdica e será realizado o mapeamento epicárdico com eletrodo decapolar após confecção da anastomose distal com perfusão seletiva para área revascularizada com a aorta pinçada e portanto sem perfusão para as demais artérias coronárias. Nesta análise será avaliado a duração do impulso do eletrograma. Concomitante será realizada fluxometria dos enxertos e comparada com o resultado obtido no mapeamento epicárdico. Resultados: A técnica é uma forma eficaz de avaliar a contratilidade miocárdica regional após a revascularização miocárdica seletiva. O fluxo intravascular dos enxertos estudados não interfere na duração do impulso durante a perfusão seletiva das áreas estudadas / At present, we have available modern tecnics of electroanatomic mapping generating tridimensional images of impulse propagation on heart chambers through intracavitary catheters. Despite this, very few scientific studies are available about epicardial electrophysiologic mapping. Intraoperative evaluation of myocardial contractility right after coronary artery bypass is visual and Echocardiographic, even though this is rarely used to this end. Therefore, there is a need for development of new methods capable of evaluate the functional impact of myocardial revascularization. Objective: Evaluate the intra-operative response of regional myocardial contractility with epicardial mapping with a decapolar catheter. Methods: 20 patients will be submitted to coronary artery bypass graft surgery and epicardial mapping with decapolar catheter was performed after distal anastomosis is made with selective perfusion on the revascularized area with cross clamped aorta, therefore without blood perfusion to the other coronary arteries. On this basis it will be evaluated the duration of the electrogram impulse. It was held the grafts flowmetry and compared to the results obtained on epicardial mapping. Results: The presented tecnic is an effective way to evaluate the regional myocardial contractility after the selective myocardial revascularization. The graft flowmetry doesn\'t interfere with the duration of the impulse obtained during the selective perfusion for the studied areas.

L’invasion de la matrice extracellulaire est le premier obstacle que les tumeurs solides rencontrent lors de leur dissémination métastatique. Il existe deux mécanismes principaux: 1) la transition épithélio-mésenchymateuse au cours de laquelle les cellules épithéliales, à l’échelle individuelle, perdent leur cohésion intercellulaire et acquièrent des capacités de motilité pour quitter leur site d’origine ; 2) l’invasion collective dans laquelle des cellules en groupe coopèrent pour migrer collectivement en se frayant un passage à travers le microenvironnement. Dans les modèles murins, on sait maintenant que des groupes ou agrégats de cellules tumorales circulantes issus du détachement de tumeurs primaires présentent une capacité accrue à coloniser des organes à distance. Cependant, les facteurs et mécanismes sous-jacents conduisant au détachement des cellules tumorales en groupe sont peu connus. Pour étudier ces mécanismes, nous avons utilisé des sphéroïdes tumoraux, modèle expérimental tri-dimensionnel (3D), qui mime le microenvironnement ainsi que les caractéristiques morphologiques et fonctionnelles de la tumeur primaire. Nos résultats indiquent que l'inhibiteur de l’activateur du plasminogène (PAI-1), une protéine matricellulaire trouvée en forte concentration dans les cancers invasifs, favorise le détachement en groupe et l’invasion collective de cellules du cancer du sein (lignée cellulaire MCF7) et du colon (lignée cellulaire HCT116) organisées en sphéroïdes tumoraux. PAI-1 a des propriétés dé-adhésives sur des cellules étalées en monocouche sur des matrices pro-adhésives et génère l’agrégation des cellules entre-elles. Ces cellules conservent leurs caractéristiques épithéliales malgré une modification importante de la dynamique du réseau d'actine.Nos résultats suggèrent que les récepteurs cellulaires de la famille des lipoprotéines de basse densité (LDL-R) sont impliqués dans les propriétés dé-adhésives de PAI-1. Dans la cellule, la transduction du signal passe par les kinases ROCK (kinase associée à la GTPase RhoA) et Janus (JAK), ce qui conduit à une phosphorylation de la chaîne légère de la myosine II (MLC2), nécessaire pour l’activité contractile de la myosine et des facteurs de transcription STAT3. En outre, ROCK, un régulateur connu de la contraction du cytoskelette d’actomyosine, est également impliqué dans l'activation de STAT3. L'inhibition de ROCK ou JAK rétablit l’adhésivité des cellules en 2D et réduit leur migration en 3D. Nos données suggèrent que PAI-1 génère des zones de forte activité contractile membranaire dans les cellules en périphérie de la tumeur via ROCK-MLC2 et JAK-STAT, ce qui promeut le détachement de groupe de cellules hautement invasives. Ce nouvel axe de signalisation fonctionnelle de PAI-1 représente une cible anti-métastatique potentielle. / Invasion of the extracellular matrix is the first obstacle that solid tumours encounter during their metastatic dissemination. There are two main mechanisms: 1) epithelial to mesenchymal transition wherein epithelial cells lose their intercellular cohesion and convert to individual migratory behaviours to escape their point of origin; 2) invasion in a collective manner, in which a group or cluster of cohesive cancer cells detaches from the tumour mass and progressively, pushes its way through the microenvironment. It is now known that circulating tumour cell clusters may result from the evasion of cohesive small groups of cells from tumours and such tumour cell clusters display an increased propensity to colonize distant organs in mouse models. However, the extracellular factor/s and the underlying mechanism that enable cell detachment, as clusters are largely unknown. To study the process of tumour cell detachment and invasion, we used a three-dimensional (3D) multicellular tumour spheroid (MCTS) model, which mimics the microenvironment as well as morphological, functional and symmetric geometry features of the primary tumour. Our results strongly indicate that the plasminogen activator inhibitor-1 (PAI-1), a matricellular protein found in high concentration at the invasive front of most cancers, promotes cancer cell cluster detachment and a collective invasion phenotype within MCTS of breast cancer MCF7 and colon cancer HCT116 cell lines. We found that PAI-1 has a de-adhesive effect which induced a multilayered cell clustering of cells spread out on a pro-adhesive matrices in 2D monolayer cultures. Cells retained their epithelial characteristics and membrane-localized E-cadherin despite significant modification of actin dynamics. PAI-1 functions as a de-adhesive molecule most likely involved low-density lipoprotein receptors at the cell surface. We report that the downstream intracellular events may be mediated through the Rho-associated kinase (ROCK) and Janus kinases (JAK) signalling pathway, resulting in phosphorylation of either myosin light chain 2 (MLC2), which is required for myosin II-mediated contractility or STAT3 transcription factors. In addition, ROCK, a known contributor to actomyosin contractility is involved in STAT3 phosphorylation and activation. Inhibition of ROCK and JAK restored adhesion of cells on 2D substratum and reduced their migration/invasion within 3D MCTS model. Our data support a model in which PAI-1 generates actomyosin contractility and high membrane activity at the tumour periphery in a JAK-STAT/ROCK-MLC2 dependent manner promoting the detachment of highly invasive cell clusters. This novel axis of functional signalling of PAI-1 is a potential anti-metastasis target.

Non-invasive remote detection of cardiac and blood displacements is an important topic in cardiac telemedicine. Here we propose kinocardiography (KCG), a non-invasive technique based onmeasurement of body vibrations produced by myocardial contraction and blood flow through thecardiac chambers and major vessels. KCG is based on ballistocardiography and seismocardiographyand measures 12 degrees-of-freedom (DOF) of body motion. The integral of kinetic energy (iK)and maximum Power (Pmax) obtained from the linear and rotational SCG/BCG signals, was computedover the cardiac cycle, and used as a marker of cardiac mechanical function. We showedthat KCG metrics show high repeatability, can be computed on 50 Hz and 1 kHz SCG/BCG signalsindifferently, that most of the metrics were highly similar when computed on different sensors,and with less than 5% of error when computed on record length longer than 60 s. Finally, weshow that KCG metrics allow detecting dobutamine-induced haemodynamic changes with a highaccuracy and present a major improvement over single axis ballistocardiography or seismocardiography.These results suggest that KCG may be a robust and non-invasive method to monitorcardiac inotropic activity. / La détection à distance et non invasive des déplacements cardiaques et sanguins est un sujet important en télémédecine. Nous proposons ici la kinocardiographie (KCG), une technique non invasive basée sur mesure des vibrations corporelles produites par la contraction du myocarde et par le flux sanguin au travers des cavités cardiaques et des principaux vaisseaux sanguins. La KCG est basée sur la balistocardiographie et la seismocardiographie et mesure 12 degrés de liberté (DOF) de mouvement corporel. L'intégrale de l'énergie cinétique (iK) et la puissance maximale (Pmax) obtenue à partir des signaux SCG / BCG linéaire et rotationnel, a été calculée au cours du cycle cardiaque, et sont utilisées comme marqueur de la fonction mécanique cardiaque. Ce travail montre que les métriques KCG sont caractérisées par une répétabilité élevée, peuvent être calculées sur des signaux SCG / BCG à 50 Hz et à 1 kHz indifféremment, que la plupart des métriques étaient très similaires lorsqu'elles étaient calculées sur différents capteurs, et avec moins de 5% d'erreur lors du calcul sur une longueur d'enregistrement supérieure à 60 s. Enfin ce travail montre que les métriques KCG permettent de détecter les changements hémodynamiques induits par la dobutamine avec précision et présentent une amélioration majeure par rapport à la balistocardiographie à un seul axe ou à la seismocardiographie. Ces résultats suggèrent que la KCG peut être une méthode robuste et non invasive pour surveiller l'activité inotrope du coeur. / Doctorat en Sciences de l'ingénieur et technologie / La défense publique a eu lieu le 05/05/2021. Cet upload remplace l'upload pécédent et contient les derniers commentaires du jury après la défense publique. / info:eu-repo/semantics/nonPublished

During the last two decades, since the heart has become a direct target for various surgical procedures for the correction of several abnormalities, interest in understanding its basic regulatory mechanisms and performance has increased considerably. Many experiments have been devised to study cardiac performance, under different circumstances, as an isolated preparation or as an integrated part of a functioning system. The results derived from these investigations not only proved to be important conceptual tools in making many observed phenomena more readily comprehensible, but also provided us with valuable basic principles to treat cardiac patients before and after open heart operations. The purpose of this paper is to investigate the control of the function of the heart in dogs with the chest and pericardium open, and under strictly controlled conditions. In spite of all the work j done in this field, there still exists some degree of confusion regarding the relative importance of autoregulatory mechanisms and extrinsic factors governing cardiac performance. Without trying to take sides as to the priority of either of these mechanisms, we have made an effort to confine our interest mainly to the intrinsic autoregulation of the heart.

L'ICAP-1 est impliqué dans la dynamique de l'intégrine et la génération de force en contrôlant l'endocytose de l'intégrine grâce à la scission dépendant de nm23 des puits endocycliques recouverts de chlatrine.L'ICAP-1 a été identifié comme un partenaire spécifique de l'intégrine b1 (Degani et al., 2002, Zhang et Hemler, 1999). Nous avons déjà montré que l'ICAP-1 est impliqué dans la réponse mécanisée aux cellules et la différenciation cellulaire d'une manière dépendante de l'intégrine b1 (Bouvard et al., 2007; Brunner et al., 2011; Faurobert et al., 2013; Millon-Frémillon et al. , 2008; Renz et al., 2015). Cependant, comme ICAP-1 est également capable d'adapter la migration cellulaire en réponse à la rigidité du substrat d'une manière indépendante de la β1-intégrine (Bouin et al., 2017), nous avons spéculé sur un rôle plus général de l'ICAP-1 dans l'adhésion cellulaire et dynamique d'adhérence focale. Pour cela, nous avons créé un environnement cellulaire où l'intégrine b1 et / ou l'ICAP-1 étaient absentes en utilisant quatre lignées cellulaires: les ostéoblastes WT, les cellules ostéoblastes KO de l'intégrine b1, les cellules ostéoblastes KAP ICAP-1 et les cellules ostéoblastes double KO b1 / ICAP-1 afin de surveiller le comportement de l'intégrine b3. Comme prévu, l'épuisement de l'intégrine b1 est associé à la perte d'étalement cellulaire et à la génération de force selon la mesure de la microscopie par force de traction. De manière surprenante, la suppression supplémentaire de ICAP-1 (b1 intégrine et ICAP-1 KO) conduit à la restauration de l'étalement cellulaire et de la génération de force qui dépend de l'intégrine b3. Ces forces médiées par l'intégrine b3 sont corrélées avec la diffusion lente de l'intégrine b3 dans les sites d'adhésion et le renouvellement lent de l'adhésion focale contenant l'intégrine b3 (FRAP / TIRF / vidéomicroscopie). Nous avons abordé la question de savoir si ICAP-1 pourrait réguler l'endocytose de l'intégrine b3 puisque ICAP-1 interagit avec nm23-H2 (Fournier et al., 2002), un nucléoside diphosphate kinases (NDPK) impliqué dans l'endocytose à médiation par dynamine en produisant du GTP à travers l'adénosine triphosphate (ATP) de conversion du diphosphate de guanosine (PIB) (Boissan et al., 2014). Nous montrons que la suppression de nm23 ou de dynamine ou de chlatrine dans les cellules épuisées dans l'intégrine b1 est capable d'imiter la perte combinée de l'intégrine b1 et de l'ICAP-1 en rétablissant l'étalement cellulaire, la génération de force et la dynamique de l'intégrine b3. Pour confirmer l'implication de l'ICAP-1 dans l'endocytose de l'intégrine b3, nous montrons que l'absorption de l'anticorps de l'intégrine b3 est efficacement bloquée dans les cellules épuisées dans ICAP-1. Nos résultats suggèrent que ICAP-1 pourrait être impliqué dans la dynamique de l'intégrine et la génération de force en contrôlant l'endocytose de l'intégrine grâce à la scission dépendant de nm23 des puits endocytaires de la couche de chlatrine. / ICAP-1 is involved in integrin dynamics and force generation by controlling integrin endocytosis through nm23-dependent scission of endocytic chlatrin coated pits.ICAP-1 has been identified as a specific partner of b1 integrin (Degani et al., 2002; Zhang and Hemler, 1999). We have previously shown that ICAP-1 is involved in cell mechanoresponse and cell differentiation in a b1 integrin dependent manner (Bouvard et al., 2007; Brunner et al., 2011; Faurobert et al., 2013; Millon-Frémillon et al., 2008; Renz et al., 2015). However, as ICAP-1 is also able to adapt cell migration in response to substrate stiffness in a β1-integrin-independent manner (Bouin et al., 2017), we speculated on a more general role of ICAP-1 in cell adhesion and focal adhesion dynamics. For this purpose we have created cellular environment where b1 integrin and/or ICAP-1 were absent by using four cell lines: WT osteoblast, b1 integrin KO osteoblast cells, ICAP-1 KO osteoblast cells and double KO b1/ICAP-1 osteoblast cells in order to monitor b3 integrin behavior. As expected, depletion of b1 integrin is associated with the loss of cell spreading and force generation according traction force microscopy measurement. Surprisingly, the supplementary deletion of ICAP-1 (b1 integrin and ICAP-1 KO) leads to restoration of cell spreading and force generation which are dependent on b3 integrin. These b3 integrin-mediated forces are correlated with slow diffusion of b3 integrin within adhesion sites and slow turnover of b3 integrin containing focal adhesion (FRAP/TIRF/videomicroscopy). We addressed the question whether ICAP-1 might regulate b3 integrin endocytosis since ICAP-1 interacts with nm23-H2 (Fournier et al., 2002), a nucleoside diphosphate kinases (NDPKs) involved in dynamin-mediated endocytosis by producing GTP through adenosine triphosphate (ATP)–driven conversion of guanosine diphosphate (GDP) (Boissan et al., 2014). We show that the deletion of either nm23 or dynamin or chlatrin in cells depleted in b1 integrin is able to mimic the combined loss of b1 integrin and ICAP-1 by restoring cell spreading, force generation and b3 integrin dynamics. To confirm the involvement of ICAP-1 in b3 integrin endocytosis, we show that the b3 integrin antibody uptake is efficiently blocked in cells depleted in ICAP-1. Our results suggest that ICAP-1 might be involved in integrin dynamics and force generation by controlling integrin endocytosis through nm23-dependent scission of endocytic chlatrin coated pits.

Die Anwendung von körperfremden Materialien zur Behandlung verschiedenster Krankheitsbilder, wie zum Beispiel als Zahnersatz oder Knochenstabilisierung, ist seit Jahrtausenden fester Bestandteil in der Medizin. Während damals hauptsächlich stabile Materialien genutzt wurden, die möglichst wenig mit dem menschlichen Körper interagieren, wird heutzutage ein anderer Ansatz verfolgt. Intelligente Materialien können nicht nur passiv die Heilung unterstützen, sondern aktiv zu ihr beitragen. Ein berühmtes Beispiel hierfür ist das Formgedächtnismaterial Nitinol, das in Stents zur Behandlung verengter Arterien eingesetzt wird. Diese Arbeit beschäftigt sich mit Eisen-Palladium, einem neuen Formgedächtnismaterial, bei dem der Effekt nicht wie bei Nitinol über eine Temperaturänderung sondern durch ein äußeres Magnetfeld induziert wird. Da man somit körpertemperaturbedingte Restriktionen in biomedizinischen Anwendungen umgehen kann, birgt Eisen-Palladium ein hohes Potential für Drug-Delivery Systeme oder mikromechanische Pumpen. Da eine optimale Verträglichkeit des Materials mit seiner biologischen Umgebung absolut unabdingbar ist, untersucht diese Arbeit verschiedene Möglichkeiten, die Oberfläche zu modifizieren und somit die Adhäsion biologischer Zellen zu unterstützen. Zu diesem Zweck wurden das Peptid RGD als spezifische Zelladhäsionssequenz, ein Plasmapolymer auf L-Lysin Basis als unspezifische Beschichtung und die Nanostrukturierung der Eisen-Palladium Oberfläche durch Glanzwinkeldeposition untersucht. Die verwendeten Methoden beinhalten Immunofluoreszenztests zur Quantifizierung der fokalen Kontakte zwischen Zellen und Material, theoretische Dichtefunktionaltheorie Rechnungen, sowie Kontraktilitätsmessungen mittels eines selbst entwickelten Biegebalkenaufbaus. Somit gelingt es in dieser Arbeit, die gegenseitigen Beziehungen des Materials mit der jeweiligen Oberflächenmodifikation mit den lebenden Zellen aus verschiedenen Blickwinkeln zu analysieren. Durch eine Kombination aus experimentellen und theoretischen Methoden werden die Stärken und Schwächen der einzelnen Funktionalisierungsmethoden beleuchtet und die Bildung fokaler Kontakte für eine verbesserte Zelladhäsion wird maßgeblich verbessert.

Familial hypertrophic cardiomyopathy (HCM) is a genetic disease largely caused by a mutation in myosin binding protein C (MYBPC3) and it affects about 1:500 population leading to arrhythmic sudden death, heart failure, and atrial fibrillation. MYBPC3 activates calcium-induced actin-myosin filament sliding within the cardiac sarcomere, creating the force necessary for heart contraction. The underlying molecular mechanisms causing HCM phenotype remain elusive, therefore, there is an urgent need for a reliable in vitro human HCM model to investigate the pathogenesis of HCM. This study utilized isogenic human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) with MYBPC3 gene mutation (wildtype, heterozygous, homozygous) and further micropatterned them into fiber-like structures on polyacrylamide hydrogels of physiological and fibrotic-like stiffnesses. Cells were cultured for an extended culture time up to 60 days and their morphology/attachment, contractility, and calcium transient were extensively and carefully evaluated. It was found that MYBPC3 knockout cells maintained the highest contraction amplitude, but had increased contraction, and relaxation durations, decreased calcium transient amplitude, as well as time to peak and decay times over the culture period in comparison to the isogenic wildtype. Overall, this study demonstrates that hiPSC-CMs can be successfully patterned and cultured for an extended time on hydrogels forming end-to-end connections, which can be served as a simple yet effective in vitro human model for studying mechanical dysfunction of HCM.

The scope of cardiac pathophysiology in sepsis has not been fully defined. Accordingly, we evaluated the effects of sepsis on heart rate (HR), HR variability, and conduction parameters in a murine model of sepsis. Electrocardiograms were recorded noninvasively from conscious mice before and after cecal ligation and puncture (CLP) or sham surgery. Responses of isolated atria to tyramine and isoproterenol were quantified to assess the functional state of sympathetic nerves and postjunctional sensitivity to adrenergic stimulation. Cecal ligation and puncture mice had lower HR compared with sham at 16 to 18 h postsurgery (sham, 741 ± 7 beats/min; CLP, 557 ± 31 beats/min; n = 6/group; P < 0.001), and there was significant prolongation of the PR, QRS, and QTc intervals. Slowing of HR and conduction developed within 4 to 6 h after CLP and were preceded by a decrease in HR variability. Treatment of CLP mice with isoproterenol (5 mg/kg, intraperitoneally) at 25 h after surgery failed to increase HR or decrease conduction intervals. The lack of in vivo response to isoproterenol cannot be attributed to hypothermia because robust chronotropic and inotropic responses to isoproterenol were evoked from isolated atria at 25°C and 30°C. These findings demonstrate that impaired regulation of HR (i.e., reduced HR variability) develops before the onset of overt cardiac rate and conduction changes in septic mice. Subsequent time-dependent decreases in HR and cardiac conduction can be attributed to hypothermia and would contribute to decreased cardiac output and organ perfusion. Because isolated atria from septic mice showed normal responsiveness to adrenergic stimulation, we conclude that impaired effectiveness of isoproterenol in vivo can be attributed to reversible effects of systemic factors on adrenergic receptors and/or postreceptor signaling.

Calcitonin gene-related peptide (CGRP) is a nonadrenergic/noncholinergic (NANC) peptide with vasodilatative/inotropic action that may benefit the failing heart. However, precise mechanisms for its in vivo inotropic action remain unclear. To assess this, dogs with normal or failing (sustained tachypacing) hearts were instrumented for pressure-dimension analysis. In control hearts, CGRP (20 pmol/kg per minute) enhanced cardiac contractility (eg, +33±4.2% in end-systolic elastance) and lowered afterload (-14.2±2% in systemic resistance, both P<0.001). The inotropic response was markedly blunted by heart failure (+6.5±2%; P<0.001 versus control), whereas arterial dilation remained unaltered (-19.3±5%). CGRP-positive inotropy was not attributable to reflex activation because similar changes were observed in the presence of a ganglionic blocker. However, it was fully prevented by the β-receptor antagonist (timolol), identifying a dominant role of sympatho-stimulatory signaling. In control hearts, myocardial interstitial norepinephrine assessed by microdialysis almost doubled in response to CGRP infusion, whereas systemic plasma levels were unchanged. In addition, CGRP receptors were not observed in ventricular myocardium but were prominent in coronary arteries and the stellate ganglia. Ventricular myocytes isolated from normal and failing hearts displayed no inotropic response to CGRP, further supporting indirect sympatho-stimulation as the primary in vivo mechanism. In contrast, the peripheral vasodilatative capacity of CGRP was similar in femoral vascular rings from normal and failing hearts in dogs. Thus, CGRP-mediated positive inotropy is load-independent but indirect and attributable to myocardial sympathetic activation rather than receptor-coupled stimulation in canine hearts. This mechanism is suppressed in heart failure, so that afterload reduction accounts for CGRP-enhanced function in this setting.

No description available.