Tesi: "Perfusion pulmonaire ex vivo"

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Olland, Anne. "Intérêt des microparticules pour l'étude de l'ischémie reperfusion en tranplantation pulmonaire basé sur un modèle de perfusion ventilation pulmonaire ex vivo chez le rat". Thesis, Strasbourg, 2016. http://www.theses.fr/2016STRAJ035.

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L’ischémie reperfusion pulmonaire et sa traduction clinique la dysfonction primaire du greffon sont responsables d’une morbi-mortalité importante en transplantation pulmonaire aussi bien à court terme qu’à long terme. Nous avons voulu faire la démonstration de la pertinence des microparticules comme marqueur de l’ischémie reperfusion pulmonaire. Nous avons reproduit et validé la stabilité d’un modèle de perfusion ventilation ex vivo de poumon de rat aussi bien en conditions normales (pas d’ischémie pulmonaire avant reperfusion) qu’en conditions extrêmes (1 h d’ischémie chaude avant reperfusion pulmonaire). Nous avons étudié la génération de microparticules par des poumons soumis à des conditions variables d’ischémie froide et d’ischémie chaude. Les poumons soumis à de fortes conditions d’ischémie froide (20h) produisent un pic précoce de microparticules d’origine épithéliale alvéolaire, leucocytaire et endothéliale. Nous en concluons que le modèle de perfusion ventilation ex vivo de poumons de rats est un modèle pertinent pour l’étude des réactions d’ischémie reperfusion. Les microparticules apparaissent comme un marqueur précoce des lésions d’ischémie reperfusion pulmonaires dans ce modèle
Lung ischemia reperfusion and its clinical expression as primary graft dysfunction are provider of immediate and long term morbidity and mortality for patients. We aimed at demonstrating the usefulness and relevance of microparticles as biomarkers for lung ischemia reperfusion injury. We first reproduced an ex vivo rat lung perfusion and ventilation experimental model. Stability of the model was validated for normal conditions (no ischemia before reperfusion) as well as for extreme conditions (1 hour warm ischemia before reperfusion). The generation of microparticles was studied in that model for variable conditions of cold ischemia and for warm ischemia. Lung submitted to strong ischemic injury (20hours cold ischemia) generate an early pike of microparticles originated from leukocyes, endothelial cells, and epithelial alveolar cells. We may conclude the ex vivo model of rat lung perfusion and ventilation is relevant for the study of lung ischemia reperfusion injury. Microparticles are relevant markers of rat lung ischemia reperfusion injury in our model

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Wolf, Julien de. "Remise en question de la procédure de perfusion pulmonaire ex vivo par modification du liquide de perfusion avec dialyse continue dans un modèle porcin". Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASL086.

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La Perfusion Pulmonaire Ex Vivo (PPEV) est une technique innovante permettant d'améliorer la fonction des poumons de donneurs à critères élargis, augmentant ainsi le nombre d'organes disponibles pour la transplantation. En ventilant et perfusant les poumons en normothermie, cette méthode permet de récupérer des poumons de qualité incertaine et de les rendre aptes à la transplantation. Cependant, la PPEV prolongée peut entraîner œdème, réponses inflammatoires et accumulation de déchets métaboliques. Pour pallier ces limitations, mes travaux de thèse ont exploré l'effet de l'intégration d'un hémodialyseur dans le circuit de PPEV afin de réguler la composition du liquide de perfusion et maintenir la viabilité pulmonaire, en évaluant les effets biologiques sur 6 et 12 heures dans un modèle porcin.Méthodes Les expérimentations ont été menées conformément aux directives de l'UE et aux réglementations françaises, approuvées par le comité éthique COMETHEA. Seize porcs ont été répartis en quatre groupes de PPEV : sans changement de liquide de perfusion, remplacement partiel horaire (protocole TORONTO), dialyse pédiatrique et dialyse adulte. La dialyse pédiatrique utilisait une membrane avec une surface efficace de 0,2 m² et un seuil de filtration de 30 kDa, tandis que la dialyse adulte utilisait une membrane avec une surface efficace de 1,8 m² et un seuil de filtration de 40 kDa. La première étude a été réalisée sur une durée de 6 heures avec les 4 groupes, et la seconde sur 12 heures avec les groupes remplacement partiel horaire et dialyse pédiatrique.Les paramètres physiologiques et métaboliques ont été mesurés, les cytokines ont été dosées par Luminex/Multiplex, et les profils d'expression génique ont été évalués par séquençage d'ARN.Résultats L'analyse des paramètres physiologiques a montré une stabilité de la compliance pulmonaire, de la pression artérielle pulmonaire et des échanges gazeux sans distinction significative entre les groupes. Les procédures de dialyse ont corrigé les déséquilibres électrolytiques et métaboliques, stabilisant les concentrations de lactate et de glucose. Cependant, les cytokines inflammatoires (TNFα, IL-6, IL-8, IL-10) ont montré une augmentation après trois heures, avec des niveaux plus élevés dans le groupe de dialyse pédiatrique.Les analyses d'expression génique ont révélé que la PPEV est associée, quelque soit le groupe, à l'activation des voies inflammatoires, de la survie cellulaire, et de la prolifération. Par contre, la dialyse pédiatrique a induit des profils d'expression prédictifs d'une plus forte activation endothéliale et d'une plus forte signalisation cytokinique par rapport au remplacement partiel horaire.Conclusion L'ajout d'un circuit de dialyse au protocole de PPEV permet un meilleur équilibre des électrolytes et du métabolisme du liquide de perfusion. Cependant, cette approche est associée à une augmentation des cytokines inflammatoires, ce qui pourrait avoir des implications négatives pour la transplantation pulmonaire. Malgré des perspectives prometteuses, des évaluations supplémentaires et des améliorations sont nécessaires avant une application clinique, notamment l'utilisation de membranes d'adsorption améliorées et l'ajout de nutriments pour optimiser le système de perfusion. Ces résultats soulignent l'importance des analyses génomiques fonctionnelles pour comprendre la réponse biologique à la PPEV et guider les améliorations futures
Ex Vivo Lung Perfusion (EVLP) is an innovative technique that enhances the function of donor lungs with extended criteria, thus increasing the number of organs available for transplantation. By ventilating and perfusing the lungs at normothermia, this method allows for the recovery of lungs of uncertain quality and makes them suitable for transplantation. However, prolonged EVLP can lead to edema, inflammatory responses, and the accumulation of metabolic waste. To address these limitations, my thesis work explored the effect of integrating a hemodialyzer into the EVLP circuit to regulate the composition of the perfusion fluid and maintain lung viability, evaluating the biological effects over 6 and 12 hours in a porcine model.MethodsThe experiments were conducted in accordance with EU guidelines and French regulations, approved by the COMETHEA ethics committee. Sixteen pigs were divided into four EVLP groups: without perfusion fluid change, hourly partial replacement (TORONTO protocol), pediatric dialysis, and adult dialysis. Pediatric dialysis used a membrane with an effective surface area of 0.2 m² and a filtration threshold of 30 kDa, while adult dialysis used a membrane with an effective surface area of 1.8 m² and a filtration threshold of 40 kDa. The first study was conducted over 6 hours with all four groups, and the second over 12 hours with the hourly partial replacement and pediatric dialysis groups.Physiological and metabolic parameters were measured, cytokines were assayed by Luminex/Multiplex, and gene expression profiles were evaluated by RNA sequencing.ResultsAnalysis of physiological parameters showed stability in lung compliance, pulmonary arterial pressure, and gas exchange without significant differences between groups. The dialysis procedures corrected electrolyte and metabolic imbalances, stabilizing lactate and glucose concentrations. However, inflammatory cytokines (TNFα, IL-6, IL-8, IL-10) increased after three hours, with higher levels in the pediatric dialysis group.Gene expression analyses revealed that EVLP is associated, regardless of group, with the activation of inflammatory pathways, cell survival, and proliferation. In contrast, pediatric dialysis induced expression profiles predictive of stronger endothelial activation and cytokine signaling compared to hourly partial replacement.ConclusionThe addition of a dialysis circuit to the EVLP protocol allows for better electrolyte and metabolic balance in the perfusion fluid. However, this approach is associated with an increase in inflammatory cytokines, which could have negative implications for lung transplantation. Despite promising prospects, further evaluations and improvements are necessary before clinical application, including the use of enhanced adsorption membranes and the addition of nutrients to optimize the perfusion system. These results highlight the importance of functional genomic analyses to understand the biological response to EVLP and guide future improvements

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Brenckmann, Vivien. "Monitorage de l'inflammation pulmonaire par le monoxyde de carbone endogène exhalé dans un modèle de poumons humains : Application lors d'optimisation de greffons en perfusion pulmonaire Ex-Vivo avant transplantation pulmonaire. Étude BreathDiag-COe". Thesis, Université Grenoble Alpes, 2020. http://www.theses.fr/2020GRALS006.

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Pour pallier au manque de greffons pulmonaires, des techniques de perfusion pulmonaire ex-vivo (PPEV) ont été développées. Les critères d’évaluation sont basés sur les paramètres physiologiques comme la qualité des échanges gazeux, les résistances vasculaires pulmonaires, la formation d'œdème, et l’aspect général des poumons.La production endogène de monoxyde de carbone (CO) est influencée par les phénomènes inflammatoires et est plus particulièrement en lien avec les mécanismes d'ischémie-reperfusion.La mesure du CO exhalé (COe) est possible grâce à un spectromètre laser (ProCeas®). Cet appareil est précis (concentrations inférieures au Ppmv) et rapide permettant un monitorage cycle à cycle, en temps réel.Le but de l'étude était d’évaluer le taux de COe des greffons pulmonaires humains en cours de procédure de PPEV et de le comparer à l’acceptation des greffons, aux autres paramètres testés et au devenir à court terme des receveurs.Matériel et méthodeDes greffons pulmonaires ont été optimisés et évalués en PPEV normothermique. Les poumons étaient progressivement réchauffés, perfusés et ventilés. S'en suivait une phase d'évaluation (incluant des manœuvres de recrutement) durant deux à quatre heures.Le ProCeas® était connecté en dérivation sur le circuit ventilatoire. La production de CO était moyennée sur cinq minutes à la fin de chaque phase de recrutement.En fin de procédure de PPEV, la décision de transplanter les poumons était prise selon les critères habituels de l'équipe chirurgicale sans avoir connaissance des valeurs de COe .Résultats et Discussion21 procédures de PPEV ont eu lieux à l’hôpital Foch de Suresnes de Décembre 2018 à Juillet 2019, dont 13 greffons à « critères élargis » (CE) et 8 issus de donneurs après arrêt cardiaque (de la catégorie III de Maastricht) (DDAC-M3).La présence de sang dans les voies aériennes faussait les résultats de COe, ainsi trois procédures ont été exclues.Il n’y avait pas de différence de COe en fonction de l’origine CE ou DDAC-M3 des poumons.Sur les 18 greffons, deux ont été définitivement récusés à la greffe. Il y avait une tendance à un COe plus élevé pour les poumons récusés (p=0,068). Cette tendance était présente dès le début des procédures.Concernant les paramètres physiologiques testés lors des procédures de PPEV, le COe était corrélé à la consommation de glucose (r=0,64 ; p=0,04) et à la production de lactates (r=0,53 ; p= 0,025). Il y avait une relation non significative avec les résistances vasculaires (p = 0,062). Il n’y avait pas de lien entre COe et formation d’œdème ni avec le rapport PaO2/FiO2 per PPEV.Concernant les données post-opératoires, en séparant les greffons en 2 groupes (COe bas Vs COe élevé, limite fixée à 0,235 Ppmv), il y avait une tendance à de meilleures capacités d’hématose (PaO2/FiO2) à 24h (p=0,052) pour ceux ayant un taux de COe bas. Tous les poumons avec taux de COe élevé ont présenté un score DPG à 3 dans les 72h (p=0,088). Il y avait également une tendance à es durées plus longues de réanimation (6 jours (+-3,25) Vs 15 jours (+-3,83), p=0,06) et de durée totale en unité de soins continus (réanimation + soins intensifs) (14,5 jours (+-2,34) vs 19 jours (+-3,4) (p=0,07)) pour les greffons avec un taux de COe élevé.ConclusionLe taux de COe per PPEV pourrait être une aide supplémentaire et précoce dans l’évaluation des poumons. Il semble pouvoir également apporter une aide pronostique pour anticiper les soins de réanimation post opératoires
To compensate the lack of pulmonary grafts, ex-vivo lung perfusion techniques (EVLP) have been developed. The evaluation criteria are based on physiological parameters such as the quality of gas exchange, pulmonary vascular resistance, edema formation, and the general appearance of the lungs. The endogenous production of carbon monoxide (CO) is influenced by inflammatory phenomena and is more particularly linked to the mechanisms of ischemia-reperfusion.The measurement of exhaled CO (eCO) is possible thanks to a laser spectrometer (ProCeas®). This device is precise (concentrations lower than Ppmv) and fast allowing cycle-to-cycle monitoring, in real time.The aim of the study was to assess the eCO level of human lung grafts during the EVLP procedure and to compare it with the acceptance of the grafts, the other parameters tested and the short-term outcome of the recipients.Material and methodLung grafts have been optimized and evaluated in normothermic EVLP. The lungs were gradually warmed, perfused and ventilated. This was followed by an evaluation phase (including recruitment maneuvers) lasting two to four hours.The ProCeas® was connected in bypass to the ventilation circuit. CO production was averaged over five minutes at the end of each recruitment procedure.At the end of the EVLP procedure, the decision to transplant the lungs was taken according to the usual criteria of the surgical team without knowing the value of eCO.Results and discussion21 procedures took place at Foch Hospital in Suresnes from December 2018 to July 2019, including 13 grafts with extended criteria (EC) and 8 from donors after cardiac arrest (Category III of Maastricht) (DDCA-M3).The presence of blood in the airways distorted the eCO results, so three procedures were excluded.There was no difference in eCO based on the EC or DDCA-M3 origin of the lungs.Of the 18 grafts, two were definitively rejected at the graft. There was a tendency for higher eCO for the recused lungs (p=0.068). This trend was present from the start of the procedures.Regarding the physiological parameters tested during EVLP procedures, eCO was correlated with glucose consumption (r=0.64; p=0.04) and lactate production (r=0.53; p=0.025). There was a non-significant relationship with vascular resistance (p = 0.062). There was no link between eCO and edema formation or the PaO2/FiO2 relationship per PPEV.Concerning the post-operative data, by separating the grafts into 2 groups (low eCO Vs high eCO, limit fixed at 0,235 Ppmv), there was a tendency to better capacities of hemostasis (PaO2/FiO2) at 24h (p=0.052) for those with a low eCO level. All lungs with high eCO levels presented a PGD score of 3 within 72 hours (p=0.088). There was also a tendency for longer durations of resuscitation (6 days (+-3.25) vs 15 days (+-3.83), p = 0.06) and total duration in the continuing care unit (resuscitation + intensive care) (14.5 days (+-2.34) vs 19 days (+-3.4) (p = 0.07)) for grafts with a high COe level.ConclusionThe eCO level per EVLP could be an additional and early aid in the evaluation of the lungs.It also seems to be able to provide prognostic help to anticipate post-operative resuscitation care

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Maciel, Miriam Beatriz de Tolledo. "Estruturação administrativa do processo de perfusão pulmonar ex vivo em normotermia para transplante em um hospital". Universidade do Vale do Rio dos Sinos, 2017. http://www.repositorio.jesuita.org.br/handle/UNISINOS/6462.

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Muitos pacientes aguardam em lista de espera por um transplante de pulmão. A perspectiva de aumentar o número de transplantes através de nova tecnologia que proporcione a utilização de órgãos não viáveis para transplante aumenta a esperança de realização do transplante. A implantação de novas tecnologias em busca de melhores resultados ou do aumento de oportunidades aos pacientes de recuperação de sua saúde é cada vez mais frequente no segmento hospitalar. Objetivo: estruturar o processo administrativo de implantação de perfusão pulmonar ex vivo em normotermia para transplantes no Hospital Dom Vicente Scherer da Santa Casa de Misericórdia de Porto Alegre. Método: foram utilizadas as ferramentas do ciclo do PDCA (Plan – Do – Check – Action) e a matriz GUT (Gravidade – Urgência – Tendência) para desenhar o fluxo do processo de implantação de perfusão pulmonar ex vivo em normotermia para transplantes. Resultados: os problemas levantados na matriz GUT foram tratados observando-se o ciclo PDCA conforme a média crítica de cada um. O limite de tratamento do problema através do plano de ação até a média critica de 20 foi definido considerando-se que, abaixo dessa média, os problemas identificados não teriam influência na implementação do processo. O projeto teve êxito em seu objetivo, sendo efetivada a estruturação do processo administrativo de perfusão pulmonar ex vivo para transplante confirmada pela execução do processo administrativo mediante simulação de todo o processo. Como resultado secundário, foi elaborado o desenho do fluxo de implementação de novas tecnologias na instituição em que foi realizado o projeto. Conclusão: Uma vez identificados e tratados os problemas, além de permitir estruturar a parte administrativa da implementação da preservação pulmonar normotérmica ex vivo, a construção do processo possibilitou elaborar uma proposta de fluxo de implementação de novas tecnologias na instituição.
Many patients are waiting on a list for a lung transplant. The prospect of increasing the number of transplants through new technology that provides the use of non-viable organs for transplantation increases the hope of transplantation. The implantation of new technologies searching for better results or to increase patients’ opportunities for recovering their health ocurrs more frequently in hospitals. Objective: To structure the administrative process of implantation of pulmonary perfusion ex vivo in normotermia for transplants at Dom Vicente Scherer Hospital of Santa Casa de Misericórdia in Porto Alegre. Method: PDCA cycle and GUT matrix’s tools were used to design the flow of the pulmonary perfusion implantation process ex vivo in normothermia for transplants. Results: The problems raised in the GUT matrix were approached by observing the PDCA cycle according to the critical average of each one. The limit for treating the problem using the action plan up to the critical average of 20 was defined, considering that below that average the problems identified would have no influence on the implementation of the process. The project achieved its goal and the structuring of the administrative process of ex vivo pulmonary perfusion for transplantation was carried out, confirmed by running the administrative process through a simulation of the whole process. As a secondary result, the design of the implementation flow of new technologies in the institution where the project was carried out was elaborated. Conclusion: Once the problems were identified and approached, besides allowing the administrative part of the implementation of normothermic pulmonary preservation ex vivo, the construction of the process made it possible to elaborate a proposal for the implementation of new technologies in the institution.

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Roman, Marius Andrei. "Examination of ex-vivo lung perfusion in porcine model". Thesis, University of Cambridge, 2016. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.709543.

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Stone, John. "Assessing the impact of ex vivo perfusion on graft immunogenicity". Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/assessing-the-impact-of-ex-vivo-perfusion-on-graft-immunogenicity(a8ad264a-8925-44ee-94c0-465d3ddd7e14).html.

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Whilst the major caveat to the success of organ transplantation remains the severe lack of donor organs, rejection is still a primary confounding factor to transplant outcomes. This is an allospecific response that occurs when the recipient immune system recognises conserved proteins on donor-derived cells as 'non-self'. Currently, all immunosuppressive regimes target the recipient immune response, ignoring the large donor immune repertoire despite these cells playing a central role in acute rejection. This is likely as a result of a lack of understanding of the temporal migration of the donor compartment and its contribution to the inflammatory cascade that ensues. The development of ex vivo perfusion provides the opportunity to assess this in isolation, with no confounding factors. Furthermore, inducing the mobilisation of passenger leukocytes on an ex vivo circuit allows their removal prior to transplantation. Reducing the inflammatory burden of donor organs has the potential to impact on the clinical outcome of patients, manifesting as a reduction in the incidence or severity of acute rejection. The aim of this PhD thesis was to characterise the donor immune compartment of lungs and kidneys, to assess the impact of ex vivo perfusion on this, and determine the post-transplant impact of removing a proportion of these cells. For this purpose, donor lungs were perfused using ex vivo lung perfusion (EVLP) and the immune compartment characterised. A comparison of EVLP versus standard transplanted lungs was performed using a porcine transplant model. Clinical parameters were recorded and a histological assessment of cellular infiltration was performed to diagnose the incidence of acute rejection. To determine if these results were translatable to other organs, a porcine model of kidney ex vivo perfusion was established. In both models, a significant efflux of donor leukocytes was observed and inflammatory mediators detected. In a transplant model of EVLP, reducing the transfer of these passenger leukocytes translated into improved clinical outcomes, manifesting as a lower incidence of acute rejection, for animals receiving EVLP lungs compared to a standard transplant. Similar benefit is likely to occur following transplantation of perfused kidneys. This study describes for the first time the contribution of donor organs to the inflammatory processes that ensue following transplantation. It is clear that this untargeted population is of significant importance in clinical outcomes. Immunomodulatory strategies to alter the donor immune environment prior to transplantation therefore warrant development.

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Motoyama, Hideki. "Plasmin administration during ex vivo lung perfusion ameliorates lung ischemia-reperfusion injury". Kyoto University, 2015. http://hdl.handle.net/2433/200436.

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Kondo, Takeshi. "β2-Adrenoreceptor Agonist Inhalation During Ex Vivo Lung Perfusion Attenuates Lung Injury". Kyoto University, 2016. http://hdl.handle.net/2433/215382.

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Izamis, Maria-Louisa 1979. "Ex vivo perfusion optimization of donor liver grafts for transplantation and cell isolation". Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/58298.

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Thesis (Ph. D.)--Harvard-MIT Division of Health Sciences and Technology, 2010.
Cataloged from PDF version of thesis.
Includes bibliographical references.
There is a constant demand for enormous numbers of high quality hepatocytes in the fields of cell transplantation, pharmacotoxicology, tissue engineering, and bioartificial assist devices. The scarcity of viable hepatocytes necessitates the use of suboptimal sources including damaged donor organs that are not transplantable. Many of these organs have potentially reversible pathologies however, that could be treated via ex vivo perfusion thereby increasing their cell yield. With the intent to translate organ recovery by perfusion into the clinic, we engineered a very simple room temperature-operated ex vivo organ perfusion system to test a rat liver model of uncontrolled non-heart beating donors. Seventeen times as many hepatocytes were recovered from livers exposed to an hour of warm ischemia (WI, 34*C) compared to untreated WI livers in only 3 hours of perfusion. Further, fresh liver hepatocyte yields were also increased by 32% postperfusion, demonstrating that both damaged and healthy donor livers could benefit from this methodology. A linear correlation between cell yield and tissue ATP content was established. This enables an accurate prediction of cell recovery during preservation and can be used as a direct measure of organ viability and the trajectory of organ recovery during perfusion resuscitation. Further, a strong correlation between perfusion flow rate and cell yield was also established supporting the use of flow rates as low as possible without causing hypoperfusion or oxygen deprivation. Morphologically and functionally, perfusion-isolated hepatocytes generally performed comparably or better than fresh hepatocytes in cell suspension and plate culture. Cumulatively, these findings strongly support the ubiquitous use of organ perfusion systems in the clinic for optimal enhancement of donor grafts.
by Maria-Louisa Izamis.
Ph.D.

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Raude, Emma. "Développement, validation et caractérisation d’un modèle ex vivo de peau humaine perfusé : FlowSkin". Thesis, Toulouse, INSA, 2020. http://www.theses.fr/2020ISAT0015.

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Les modèles organotypiques tels que les explants de peau humaine sont les modèles les plus complexes et parmi les plus représentatifs de la peau in vivo existants à ce jour pour tester l’efficacité ou l’innocuité de molécules d’intérêts thérapeutiques au stade des études pré-cliniques. Cependant, l’absence de circulation sanguine et lymphatique dans ces modèles reste une limite importante dans l’homéostasie du tissu, notamment pour prédire les réponses de la peau à un traitement. De plus, les échanges en nutriments et en oxygène n’étant possibles que par diffusion, la durée de vie de ces modèles reste limitée. Différentes stratégies ont été mises en place afin de contrôler les mécanismes de transports moléculaires au sein de tissus biologiques. La microfluidique offre un fort potentiel pour contrôler la convection et la diffusion permettant l’échange de composés dans ces modèles de peau.L’objectif de ce projet est de développer, caractériser et valider un modèle de peau humaine ex vivo perfusé. Le but de cette perfusion intra-tissulaire est de favoriser les échanges de nutriments, d’oxygène ou de médicaments, mais également d’améliorer l’élimination des déchets métaboliques.Le premier objectif de mes travaux a consisté à mettre en place un flux intra-tissulaire dans un explant de peau humaine, et à développer un procédé permettant de maintenir l’explant perfusé en culture pendant plusieurs jours. Pour cela, un dispositif poreux a été implanté dans le derme du modèle ex vivo de peau humaine NativeSkin, développé par la société Genoskin, puis relié à un système microfluidique permettant l’infusion de composés au sein du tissu.Le deuxième objectif a consisté à développer des méthodes d’analyse de la diffusion de composés dans des explants de peau. Quatre méthodes ont été développées : l’évaluation macroscopique et qualitative de la diffusion à l’aide d’un colorant, l’étude de la diffusion en temps réel par radiographie à rayons X, l’étude de la diffusion en trois dimensions par tomographie à rayons X, et enfin l’analyse de la diffusion de dextrans fluorescents de différents poids moléculaires, sur coupes histologiques. Un modèle numérique permettant de simuler la diffusion dans le modèle de peau a également été développé sur le logiciel COMSOL, permettant de prédire le profil de diffusion d’un composé.Le troisième et dernier objectif a consisté à déterminer les paramètres de perfusion permettant une bonne diffusion des composés dans l’explant de peau, sans toutefois endommager le tissu. Une première série d’expériences (8 donneurs) a été réalisée sur des modèles perfusés à flux constant (2,5µL/min) avec du milieu de culture, pendant 10 jours. Les résultats ont montré qu’à l’issue de la culture, les modèles de peau ne présentent pas d’altération de la viabilité cellulaire ni de l’intégrité du tissu, avec un maintien de la prolifération et du métabolisme cellulaire. Cependant, la caractérisation de la diffusion dans le modèle a démontré un manque de reproductibilité dans les expériences, avec d’importantes variabilités inter et intra-donneurs. De plus, la perfusion de dextrans de différents poids moléculaires a démontré que la diffusion de composés de hauts poids moléculaires était limitée. Afin de pallier ces limites, nous avons proposé une nouvelle méthode de perfusion basée sur une modulation de la pression au sein du dispositif. L’application d’une légère surpression au sein du dispositif poreux permet d’améliorer la reproductibilité et l’efficacité des échanges moléculaires au sein de l’explant.Les résultats obtenus positionnent le modèle FlowSkin ainsi développé comme un nouvel outil pertinent pour évaluer l’efficacité ou la toxicité de molécules administrées par voie intraveineuse, directement sur de la peau humaine. De plus, la perfusion de transporteurs d’oxygène via ce système pourrait permettre de prolonger la durée de vie et donc d’améliorer encore la pertinence du modèle de peau ex vivo
Organotypic models as human skin explants are the most complex and among the most representative of in vivo skin existing today to test the efficacy or the safety of molecules of therapeutic interest during preclinical studies. However, the loss of vascularization and lymphatic system in these models remains a major limitation in tissue homeostasis that impedes the prediction of skin responses to a treatment. In addition, exchanges of nutrients and oxygen being limited to diffusion, models lifetime is limited. Different strategies have been implemented to study and improve mass transport mechanism in such models. Microfluidics offers a great potential to control diffusion and convection mechanisms that permit molecular exchanges in skin models.The objective of this project is to develop, characterize and validate an ex vivo perfused human skin model. The purpose of this intra-tissue infusion is to promote the exchanges of nutrients, oxygen or drugs, but also to improve metabolic waste elimination.The first objective of my work consisted in implementing an intra-tissue flow in a human skin explant, and in setting up a process to maintain the perfused model in culture for several days. To this end, a porous device was implanted in the dermis of the ex vivo human skin model NativeSkin, developed by the company Genoskin. The implantable device is then connected to a microfluidic system allowing the infusion of compounds within the tissue.The second objective was to develop analysis methods of the diffusion of compounds in skin explants. Four methods have been developed: macroscopic and qualitative evaluation of the diffusion using a dye, the study of the diffusion in real time by X-ray radiography, the study of the diffusion in three dimensions by X-ray tomography, and finally the analysis of the diffusion of fluorescent dextrans of different molecular weights, on histological sections. A numerical model allowing to simulate the diffusion in the skin model has also been developed using COMSOL software, allowing to predict the diffusion profile of a compound.The third and last objective of my work was to determine perfusion parameters allowing efficient molecular exchanges of compounds in the skin explant, but without damaging the tissue. A first series of experiments (8 donors) was carried out on models perfused with a constant flow-rate (2.5 µL/min) with culture medium, for 10 days. The results showed that at the end of the culture, skin models did not show any alteration in cell viability or tissue integrity, with maintenance of cell proliferation and metabolism. However, diffusion characterization in the model demonstrated a lack of reproducibility in the experiments, with significant inter and intra-donor variability. In addition, the infusion of different molecular weights dextrans has demonstrated that the mass transport of high molecular weight compounds was limited through the implantable device. We demonstrated that the control of the fluid pressure is critical and that imposing a pulsatile injection with slight overpressures improves the efficiency and reproducibility of the molecular species delivery and collection in the explant.These results have shown the potential of the developed FlowSkin model as a new tool to study the efficacy or toxicity of intravenously administered drugs directly onto human skin. In addition, the combination of FlowSkin with perfusion of oxygen carriers offers unique opportunities to extend the lifetime and further improve the relevance of such ex vivo skin model

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Medeiros, Israel Lopes de. "Comparação entre as soluções de preservação pulmonar Perfadex® e LPD-G nacional em pulmões com um modelo de perfusão pulmonar ex vivo". Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/5/5156/tde-25042012-104103/.

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INTRODUÇÃO: As técnicas de preservação pulmonar visam a melhorar a qualidade do enxerto e aumentar sua tolerância ao período de isquemia fria. A técnica mais usada atualmente consiste na perfusão da artéria pulmonar com Perfadex. O alto custo associado à importação dessa solução e as dificuldades logísticas dos portos e aeroportos brasileiros com relação a materiais médicohospitalares têm causado problemas para os centros de transplante pulmonar brasileiros. Daí a necessidade de uma solução de preservação pulmonar produzida no Brasil. O objetivo desse estudo é comparar a solução Perfadex com a solução de fabricação nacional LPD-G, quanto ao grau de lesão de isquemia-reperfusão, em um modelo de perfusão pulmonar ex vivo (PPEV). MÉTODOS: Foram usados doadores em morte cerebral, cujos pulmões foram recusados. Cada caso era incluído aleatoriamente em um dos grupos: Grupo 1, a preservação pulmonar era realizada com Perfadex, e Grupo 2, era usado o LPD-G, solução fabricada no Brasil com composição idêntica a do Perfadex. Após a captação, os pulmões eram armazenados a 4 °C por 10 horas. A reperfusão ocorria em um sistema de PPEV, no qual o bloco pulmonar era ventilado e perfundido por uma solução acelular a 37 °C por 60 minutos. A lesão de isquemia-reperfusão era medida através de parâmetros funcionais (gasometria, resistência vascular pulmonar, complacência pulmonar, relação peso úmido/peso seco) e histológicos. Foram feitas biópsias pulmonares em 3 tempos: antes da captação, após o período de isquemia fria e depois da reperfusão. Vários critérios foram usados (edema alveolar, edema intersticial, hemorragia etc.) para criar um Escore de Lesão Pulmonar (ELP). A contagem de células apoptóticas foi feita usando a metodologia TUNEL (TdT-mediated dUTP nick end labeling). RESULTADOS: Após a reperfusão, a capacidade de oxigenação média foi de 405,3 mmHg no Grupo 1 e 406,0 mmHg no Grupo 2 (p = 0,98). A mediana da resistência vascular pulmonar nos pulmões do Grupo 1 foi de 697,6 dina.s.cm-5, enquanto no Grupo 2, esse valor foi de 378,3 dina.s.cm-5 (p = 0,035). A complacência pulmonar média ao final da reperfusão foi de 46,8 cmH2O no Grupo 1 e de 49,3 ml/cmH2O no Grupo 2 (p = 0,816). A razão entre o peso úmido e o peso seco foi em média 2,06 e 2,02 nos Grupos 1 e 2, respectivamente (p = 0,87). Na biópsia realizada após reperfusão, o ELP médio foi de 4,37 e 4,37 nos Grupos 1 e 2, respectivamente (p = 1,0); a contagem de células apoptóticas foi de 118,75/mm2 e 137,50/mm2 nos Grupos 1 e 2, respectivamente (p = 0,71). CONCLUSÕES: A qualidade da preservação pulmonar obtida com a solução LPD-G nacional é semelhante a obtida com o Perfadex. A aplicação clínica da nova solução pode reduzir custos, facilitando a manutenção e a abertura de centros de transplante pulmonar
INTRODUCTION: Pulmonary preservation techniques aim at improving graft quality and increasing tolerance during reperfusion and cold ischemia times. Currently, the most used technique consists of pulmonary artery anterograde perfusion with Perfadex. The high cost associated with the importation of this solution and the logistical difficulties of our ports and airports regarding medical supplies have caused problems for lung transplant centers in Brazil. Therefore there is need for a preservation solution manufactured in Brazil. The aim of this study is to compare the pulmonary preservation solutions Perfadex and LPD-G manufactured in Brazil in an ex vivo lung perfusion (EVLP) model. METHODS: Donors with brain death, whose lungs had been declined by transplantation teams were used. Cases were randomized into two groups: in Group 1, Perfadex was used for pulmonary preservation. In Group 2, LPDnac, a solution manufactured in Brazil and whose compositon is identical to Perfadex, was used. After harvesting, lungs were stored at 4 °C for 10 hours. An EVLP system was used and the pulmonary block was ventilated and perfused by an acellular solution at 37 °C for 60 minutes. Ischemic-reperfusion injury was measured by functional (blood gas, pulmonary vascular resistance, lung compliance, wet/dry weight ratio) and histological parameters. Pulmonary biopsies were performed at three time points: before harvesting, 10 hours after cold ischemia and 60 minutes after reperfusion. Samples were prepared for light microscopy analysis. Several criteria were used (alveolar edema, interstitial edema, hemorrhage etc.) to create a lung injury score (LIS). Apoptotic cell count was carried out using the TUNEL methodology (TdT-mediated dUTP nick end labeling). RESULTS: After reperfusion, mean oxygenation capacity was 406.0 mmHg in Group 2 and 405.3 mmHg in Group 1 (p = 0.98). Mean pulmonary vascular resistance in Group 2 lungs was 378.3 dina.s.cm-5, whereas in Group 1 it was 697.6 dina.s.cm-5 (p = 0.035). Mean pulmonary compliance by the end of reperfusion was 49.3 ml/cmH2O in Group 2 and 46.8 cmH2O in Group 1 (p = 0.816). Mean wet/dry weight ratio was 2.02 and 2.06 in Groups 2 and 1, respectively (p = 0.87). Mean LIS for the biopsy performed after reperfusion was 4.37 and 4.37 in Groups 2 and 1, respectively (p= 1.0); apoptotic cell count was 137.50/mm2 and 118.75/mm2 in Groups 2 and 1, respectively (p = 0.71). CONCLUSION: The preservation solution manufactured in Brazil proved to be as good as Perfadex. The clinical application for the new solution may reduce costs, favoring the maintenance and opening of pulmonary transplantation centers

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Brunkwall, Jan. "On prostanoid release from animal and human vessels in an ex vivo perfusion model". Malmö, Sweden : [s.n.], 1990. http://books.google.com/books?id=SgJrAAAAMAAJ.

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Metcalfe, Matthew Stephen. "Warm perfusion of ischaemically damaged kidneys : ex-vivo function, viability assessment and preservation efficacy". Thesis, University of Leicester, 2003. http://hdl.handle.net/2381/29433.

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Background: The shortage of kidneys for renal transplantation has prompted renewed interest in non-heart-beating donors (NHBD). While this may increase the number of transplants, it also increases the primary non-function (PNF) rate. This is caused by excessive warm ischaemic injury in some NHBD, and has hindered their more widespread use. A reliable pre-transplant test of organ viability, and a preservation method minimising additional iscahemic damage, would allow the PNF rate to be reduced. The aims of this thesis were to explore the potential of warm ex-vivo perfusion as a preservation method and a means of diagnosing viability pre-transplantation. Methods: Warm ex-vivo perfusion of ischaemically injured porcine kidneys with an oxygenated emulsion of a perflourochemical in tissue culture fluid was used to measure ex-vivo function and preserve kidneys. A cadaveric model was used to assess the relationship of ex-vivo function and warm ischaemic time. An autotransplant model was used to determine the relationship of ex-vivo to post-transplant function, and to compare the efficacy of preservation by warm perfusion with conventional hypothermic techniques of static storage and pulsatile perfusion. Post-transplant outcome measures were survival, renal function and histology. Results: WIT correlated well with ex-vivo function. Ex-vivo function correlated with post-transplant function in terms of survival (and therefore the immediate life supporting function of the kidneys), but not to the extent that it could be used to predict viability better than knowing the WIT alone. The efficacy of warm perfusion was indistinguishable from hypothermic static storage. However hypothermic pulsatile perfusion was slightly superior to both other techniques. Conclusions: Warm perfusion as used in this thesis was broadly equivalent in efficacy to conventional hypothermic organ preservation techniques. Although ex-vivo function correlated with post-transplant function, the correlation was not tight enough to support a diagnostic role for ex-vivo function in viability determination.

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Bhend, Tobias. "Development of a perfusion system for ex vivo studies of working large mammalian hearts /". [S.l.] : [s.n.], 2008. http://opac.nebis.ch/cgi-bin/showAbstract.pl?sys=000277026.

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Vandewiele, Stephanie [Verfasser], e Jan-Michael [Akademischer Betreuer] Abicht. "Xenogene ex-vivo Perfusion von transgenen hCD46 Schweineherzen / Stephanie Vandewiele ; Betreuer: Jan-Michael Abicht". München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2020. http://d-nb.info/1211957446/34.

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Strobel, Steffen Peter. "Die ex-vivo-Perfusion hDAF-transgener Kaninchennieren mit Humanblut: ein Modell für die humane Xenotransplantation". Ulm : Universität Ulm, Medizinische Fakultät, 2004. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB11482174.

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Jay, Nath. "The clinical benefits and metabolic mechanisms of ex vivo machine perfusion of kidneys prior to transplantation". Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7647/.

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Hypothermic machine perfusion (HMP) is well established in the practice of renal transplantation and is associated with improved short and long-term outcomes for selected organs. Despite the advantages of this therapy during the period prior to transplantation, the mechanisms by which these benefits occur are not entirely clear and are likely to include factors additional to improved flow dynamics. In the first part of this thesis, using both a local and national transplant dataset, I aim to establish the benefits (if any) and rationale for HMP relevant to current UK practice for both deceased and live donor kidneys. In the second part of this thesis the mechanisms by which HMP exert benefit are further interrogated, with a particular focus on metabolism. Nuclear magnetic resonance (NMR) spectroscopy is the principal modality through which this is investigated and in addition to established 1D 1H NMR protocols, glucose tracer studies using 2D 13C NMR are described. Whole organ ex vivo perfusion is studied in this work using human kidneys (both transplanted and non-transplanted) and porcine organs, with the porcine model validated for metabolic studies. In the final section, methods to modify metabolism during HMP are attempted, with the effects of supplemental oxygenation described.

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Sjöberg, Ludvig. "Concept for Improvement of Afterload in an Ex Vivo Heart Evaluation System". Thesis, Malmö universitet, Fakulteten för teknik och samhälle (TS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-20350.

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Hjärtevaluering är avsett för att öka antalet transplanterade donerade hjärtan med målet att bli standardbehandling i samband med hjärttransplantation. Anledningen till behovet av hjärtevaluering är att samtidigt som människor dör i väntan på ett nytt hjärta så kasseras donerade hjärtan på grund av osäkerhet kring deras förmåga att skapa tillräckligt blodtryck och -flöde i mottagarens kropp.Detta arbete behandlar utveckling av koncept av en komponent i ett hjärtevalueringssystem som utvecklas av Igelösa Life Science AB. Komponenten är ett flödesmotstånd som kallas afterload och som används för att utvärdera ett donerat hjärtas förmåga att skapa blodtryck.Syftet med detta arbete är att förbättra användbarheten av hjärtevalueringssystemet för att öka antalet transplanterade hjärtan och på så vis rädda liv. Målet är att ta fram ett koncept för en afterload som har potential att lösa problem som identifierats under experimentella körningar av systemet. De huvudsakliga problemen är att en tillräcklig skillnad mellan det diastoliska och systoliska trycket inte kan uppnås samt och att afterloaden kräver en sterilklädd person för att styras.Arbetet resulterar i ett koncept som från utanför det sterila fältet som afterloaden verkar i kan styra flödesmotståndet och skapa flödesmotstånd som är tillräckligt för att utföra hjärtevaluering. Förslag på framtida arbete är att vidareutveckla konceptet genom att undersöka behov av övertrycksskydd i styrsystemet för flödesmotståndet samt att göra komponent- och materialval.
Today there are waiting lists for people in need of a heart through transplantation and every year people in these lists die due to deficiency of donated, transplantable hearts. Many of the hearts donated are discarded due to uncertainty regarding their condition, such hearts are called marginal hearts. The high number of marginal hearts have led Igelösa Life Science AB to develop a system for evaluating the actual performance of a donated heart ex vivo with the aim to prove transplantability of otherwise marginal hearts. The heart evaluation procedure is done in a stand-alone device prior to the implantation, and is to create proof of a donated heart's compatibility with the recipient. The proof comes mainly from the heart's ability to produce blood pressure.To simulate the arterial blood flow resistance, a component called afterload has been developed as a part of the heart evaluation system. It is connected to the outlets of an ex vivo heart. The aim with the heart evaluation procedure is to verify that the donated heart is in a sufficiently good condition to create blood pressure and flow in the recipient's body.The purpose of this work is to increase the number of donated hearts transplanted by improving the usability of the heart evaluation system. This work is focused on the afterload and aims to solve problems identified during experimental use, such as controllability of the flow resistance and making it controllable from outside the sterile field in which it operates.The work results in a concept for an afterload that controls the flow resistance by an adjustable volume which is mounted outside the sterile field. Further development of this concept might include component selection for the control system for the flow resistance and design of pressure relief that might be necessary.

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Elkhaili, Hassan. "Pharmacocinétique in vivo et pharmacodynamie in vitro / ex vivo chez le microporc yucatan du céfépime, du cefpirome et du méropénème face à des bactéries multirésistantes". Strasbourg 1, 1997. http://www.theses.fr/1997STR15036.

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Andreasson, Anders S. I. "An evaluation of cellular and molecular mechanisms of donor lung reconditioning during human ex-vivo lung perfusion". Thesis, University of Newcastle upon Tyne, 2017. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.750388.

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Background Donor lungs not deemed suitable for immediate transplantation may be reconditioned using ex-vivo lung perfusion (EVLP). The objective identification of which donor lungs can be successfully reconditioned and will function well post-transplant has not yet been established. Aim To characterise physiological, microbiological, and immunological changes during clinical EVLP and evaluate their association with transplant outcome and cellular changes during perfusion. Methods In two cohorts of rejected donor lungs undergoing clinical EVLP, microbial load in bronchoalveolar lavage fluid (BAL) and markers of inflammation and tissue injury in perfusate, BAL, and lung tissue were examined. An in vitro model of neutrophil adherence to lung vasculature was used to evaluate endothelial activation in response to perfusate fluid. Results In consecutive cohorts, bacterial loads in BAL were significantly reduced after EVLP with high-dose antibiotics in the perfusate. Yeast loads increased when no anti-fungal treatment was given, but were reduced when prophylactic anti-fungal treatment was added. The most effective markers to differentiate in-hospital Survival from Non-survival post-transplant were perfusate IL-lp (AUC=1.00, p=0.002) and TNF-a (AUC=0.95, p=0.006) after 30 minutes of EVLP.

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Gennai, Stéphane. "Effets de la cyclosporine A sur des poumons porcins reperfusés ex vivo". Thesis, Grenoble, 2013. http://www.theses.fr/2013GRENS012/document.

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Objectif De nombreux travaux ont souligné le rôle de la Cyclosporine A (CsA) dans la prévention des lésions d'ischémie-reperfusion (I/R) mais aucun n'a été effectué sur poumons isolés de grands mammifères. Notre objectif était de mesurer pour la première fois les effets de la CsA sur les lésions d'I/R dans un modèle de poumons porcins reperfusés ex vivo, en évaluant plusieurs doses de CsA pour différents temps d'ischémie. Méthodes L'expérimentation A a été conduite sur 4 groupes de 8 paires de poumons chacune : un groupe contrôle et 3 groupes recevant différentes concentrations de CsA (1, 10 ou 30 μM) au moment de l'ischémie et au début de la reperfusion, après 2 heures d'ischémie. L'expérimentation B a été conduite sur 3 groupes de 5 paires de poumons chacune. Les poumons de chaque paire étaient séparés juste après le début de l'ischémie. Les premiers poumons étaient évalués après une ischémie de 2 heures (jour 0), sans CsA. Les seconds poumons étaient évalués après une ischémie de 24 heures (jour 1), soit sans soit avec CsA (1 ou 5 μM), administrée le cas échéant au début de la reperfusion. Résultats La CsA augmentait le rapport PO2/FiO2 avec un effet dose mais augmentait également la pression artérielle pulmonaire, la pression capillaire et les résistances vasculaires pulmonaires, à 10 et 30 μM mais pas à 1 ni 5 μM. Les poumons qui recevaient 30 μM de CsA affichaient des concentrations élevées en cytokines pro-inflammatoires. La concentration en RAGE (receptor for advanced glycation endproducts) dans le lavage broncho-alvéolaire diminuait avec la CsA à J1 en comparaison à J0. Conclusions Lors de l'I/R pulmonaire, les bénéfices cellulaires des doses élevées de CsA sont contrebalancés par ses effets hémodynamiques sur la microvascularisation. A faibles doses, la CsA semble améliorer la fonction pulmonaire
Objective Several works highlighted the role of Cyclosporine A (CsA) in the prevention of ischemia reperfusion (I/R) injuries but none on isolated lungs of big mammals. Our objective was to measure for the first time the effects of CsA in I/R injuries in an ex vivo reperfused pig lungs model, by evaluating several doses of CsA for different times of ischemia. Methods Experimentation A was performed on 4 groups of 8 pairs of lungs each: a control group and 3 groups receiving different concentrations of CsA (1, 10 or 30 μM) at the time of ischemia and at the beginning of the reperfusion, after a 2 hours ischemia. Experimentation B was performed on 3 groups of 5 pairs of lungs each. Lungs from each pair were separated just after the beginning of ischemia. The first lungs were evaluated after a 2 hours ischemia (day 0), without CsA. The second lungs were evaluated after a 24 hours ischemia (day 1), either without or with CsA (1 or 5 μM), administered when appropriate at the beginning of the reperfusion. Results CsA improved the PO2/FiO2 ratio with a dose dependent effect but increased pulmonary arterial pressure, capillary pressure, and pulmonary vascular resistances, at 10 and 30 μM but neither at 1 or 5 μM. Lungs receiving 30 μM of CsA displayed elevated concentrations in pro-inflammatory cytokines. Concentrations in RAGE (receptor for advanced glycation endproducts) in broncho-alveolar lavage decreased with CsA at day 1 compared to day 0. Conclusions During pulmonary I/R, the cellular benefits of high doses of CsA are counterbalanced by its hemodynamic effects on microvascularisation. At low doses, CsA seems to improve lung function

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Strobel, Steffen Peter [Verfasser]. "Die ex-vivo-Perfusion hDAF-transgener Kaninchennieren mit Humanblut : ein Modell für die humane Xenotransplantation / Steffen Peter Strobel". Ulm : Universität Ulm. Medizinische Fakultät, 2004. http://d-nb.info/1015471129/34.

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Montigaud, Yoann. "Modèles précliniques ex vivo pour l'étude de la délivrance pulmonaire d'aérosols dans le traitement de pathologies pulmonaires". Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEM028.

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La délivrance pulmonaire semble être une voie d’administration préférentielle pour le traitement des pathologies respiratoires mais nécessite un ciblage des dépôts pour accroître leur efficacité et réduire le risque d’effets indésirables. Afin d’améliorer les dispositifs d’aérosolthérapie de futures recherches sont nécessaires. Les restrictions éthiques liées à l’expérimentation sur la personne humaine ne sont pas compatibles avec de tels besoins. Des modèles précliniques sont nécessaires mais manquent parfois de pertinence ou sont difficilement extrapolables. Ces travaux de thèse ont donc pour objectif de développer un panel de modèles précliniques respiratoires afin de systématiser les connaissances pour permettre un transfert clinique facilité des technologies d’aérosolthérapie. Pour chaque modèle ex vivo développé, le profil de dépôt des aérosols est étudié et comparé à des données in vivo humaines et animales, afin de s’assurer de l’extrapolabilité des résultats et du placement relatif du modèle par rapport aux modèles existants. Des applications ont été réalisées, telles que la recherche d’une position optimale pour le nébuliseur en ventilation mécanique invasive ou l’étude de la régionalisation des dépôts d’un dispositif de type cigarette électronique. Les différents modèles précliniques ex vivo développées ont montré des profils de dépôts d’aérosols similaires à ceux rencontrés chez des patients ainsi que leur utilité en tant que nouvel outil de recherche préclinique, complémentaires aux modèles précliniques existants dans le cadre d’une approche 3R de la recherche en aérosolthérapie
Pulmonary delivery seem to be a preferential choice for the treamt of respiratory diseases. However, optimal targeting should be reached to increase efficacy and decrase the risk of side effects. Thus, research is needed to improve aerosol delivery devices. However, ethical restrictions related to human experiment are not in agreement with the previous statement. Therefore, preclinical model are needed but could lack of relevance or generated date could be hard to extrpolate. The present work aimed to develop a panel of preclinical ex vivo respiratory models to systematise knowledge to facilitate the clinical transfer of aerosol technologies. For each developed ex vivo model, the aerosol deposition pattern was assessed and compared to human and/or animal data to ensure the extrapolability of the results and to position the model among the available preclinical models. Applications, such as the optimal position of a nebuliser during invasive mechanical ventilation or the deposition profile of electronic cigarette aerosol, were performed. The developed ex vivo models showed comparability with patients deposition profile of aersosol, as well as their utility as a new preclinical tool fitting 3R guidelines to complete exisiting preclinical models in aerosol therapy

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Gennai, Stephane. "Effets de la cyclosporine A sur des poumons porcins reperfusés ex vivo". Phd thesis, Université de Grenoble, 2013. http://tel.archives-ouvertes.fr/tel-00949226.

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Objectif De nombreux travaux ont souligné le rôle de la Cyclosporine A (CsA) dans la prévention des lésions d'ischémie-reperfusion (I/R) mais aucun n'a été effectué sur poumons isolés de grands mammifères. Notre objectif était de mesurer pour la première fois les effets de la CsA sur les lésions d'I/R dans un modèle de poumons porcins reperfusés ex vivo, en évaluant plusieurs doses de CsA pour différents temps d'ischémie. Méthodes L'expérimentation A a été conduite sur 4 groupes de 8 paires de poumons chacune : un groupe contrôle et 3 groupes recevant différentes concentrations de CsA (1, 10 ou 30 μM) au moment de l'ischémie et au début de la reperfusion, après 2 heures d'ischémie. L'expérimentation B a été conduite sur 3 groupes de 5 paires de poumons chacune. Les poumons de chaque paire étaient séparés juste après le début de l'ischémie. Les premiers poumons étaient évalués après une ischémie de 2 heures (jour 0), sans CsA. Les seconds poumons étaient évalués après une ischémie de 24 heures (jour 1), soit sans soit avec CsA (1 ou 5 μM), administrée le cas échéant au début de la reperfusion. Résultats La CsA augmentait le rapport PO2/FiO2 avec un effet dose mais augmentait également la pression artérielle pulmonaire, la pression capillaire et les résistances vasculaires pulmonaires, à 10 et 30 μM mais pas à 1 ni 5 μM. Les poumons qui recevaient 30 μM de CsA affichaient des concentrations élevées en cytokines pro-inflammatoires. La concentration en RAGE (receptor for advanced glycation endproducts) dans le lavage broncho-alvéolaire diminuait avec la CsA à J1 en comparaison à J0. Conclusions Lors de l'I/R pulmonaire, les bénéfices cellulaires des doses élevées de CsA sont contrebalancés par ses effets hémodynamiques sur la microvascularisation. A faibles doses, la CsA semble améliorer la fonction pulmonaire.

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Oommen, Anson Jacob. "Assessing the role of Polyphenols as a vascular protectant against Drug Induced Vascular Injury". Wright State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=wright1560292217772559.

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Maignan, Maxime. "Intérêt du monoxyde de carbone comme marqueur non invasif des lésions d’ischémie-reperfusion de poumons reconditionnés ex vivo". Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAS030/document.

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Rationnel : Le développement des techniques de reperfusion pulmonaire ex vivo (Ex vivo lung perfusion : EVLP) vise à réduire la pénurie d'organes disponibles pour la transplantation. Le monoxyde de carbone (CO) pourrait aider à la sélection des greffons en cours d'EVLP puisque sa production endogène est augmentée en situation d'ischémie reperfusion. Objectifs : Mettre au point une technique de mesure du CO exhalé (eCO) lors de l'EVLP et étudier ses variations en fonction des lésions d'ischémie reperfusion. Méthodes : À partir d'un modèle porcin d'EVLP et à l'aide d'un appareil de spectrométrie laser basé sur le principe d'une cavité résonnante (optical-feedback cavity-enhanced absorption spectroscopy : OF-CEAS), eCO était mesuré selon différents paramètres ventilatoires, en ambiances polluées par des gaz pauvres (< 0,015ppmv) ou riches (9ppmv) en CO et après perfusion d'un inhibiteur de l'hème oxygénase (SnPP). eCO était ensuite comparé après 30 min (J0) ou 24 h (J1) d'ischémie froide et sa valeur prédictive pour sélectionner des greffons était calculée.Résultats : La concentration d'eCO de poumons isolés était de 0,45 ± 0.19 ppmv. Les pics d'eCO se produisaient pendant la phase expiratoire. Ni les variations de fraction inspirée en oxygène, ni la pollution de l'air ambiant ne modifiaient eCO. Les concentrations d'eCO n'étaient pas différentes après perfusion de SnPP. eCO était plus élevé à J1 par rapport à J0 (1,35 ± 0,259 ppmv vs. 0,951 ± 0,313, p = 0,01) et était corrélé à un indice de perméabilité de la membrane alvéolo capillaire. La meilleure valeur seuil d'eCO déterminée à partir de la courbe ROC était 0,860 ppmv (sensibilité de 1 (0,31 – 1), spécificité de 0,44 (0,15 – 0,77), valeur prédictive positive de 0,37 (0,10 – 0,74), valeur prédictive négative de 1 (0,39 – 1)). Conclusions : La mesure d'eCO en condition d'EVLP est faisable. eCO est significativement augmenté lorsque les lésions d'ischémie reperfusion sont accrues mais eCO ne peut pas être utilisé de façon isolée pour sélectionner les greffons pulmonaires
Rationale: Ex vivo lung perfusion (EVLP) is a promising technique to reduce the shortage of organs available for transplantation. Carbon monoxide (CO) might help in the selection of grafts during EVLP as its endogenous production is increased by ischemia reperfusion.Objectives: To develop a measurement technique of exhaled CO (eCO) during EVLP and to study its variations depending on ischemia reperfusion injuries.Methods: Using a pig model of EVLP and using a laser spectrometer technique based on the principle of a resonant cavity (optical feedback cavity-enhanced absorption spectroscopy-OF-CEAS), we measured eCO under different ventilatory parameters, various polluted environments with poor (<0,015ppmv) or rich (9ppmv) CO gas, and after infusion of an inhibitor of heme oxygenase (SnPP). We then compared eCO after 30 min (D0) or 24 h (D1) of cold ischemia and determined the predictive value of eCO to select lung grafts.Results: In isolated lungs, the concentration of eCO reached 0.45 ± 0.19 ppmv. eCO peaks during the expiratory phase. Neither variations of the fraction of inspired oxygen, nor the pollution of the ambient air altered eCO. eCO concentrations were not different after SnPP infusion. eCO was higher on day 1 compared to day 0 (1.35 ± 0.259 vs. 0.951 ± 0.313 ppmv, p = 0.01) and correlated with an index of the permeability of the alveolar capillary membrane. The best treshold value of eCO determined from the ROC curve was 0.860 ppmv (sensitivity 1 (0.31 to 1), specificity of 0.44 (0.15 to 0.77), positive predictive value of 0, 37 (0.10 to 0.74), negative predictive value of 1 (0.39 to 1)).Conclusions: Measurements of eCO during EVLP is feasible. eCO is significantly higher when ischemia-reperfusion injuries are increased. However, eCO can not be used in isolation to select lung grafts

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Menaouar, Ahmed. "Mécanismes de l'oedème pulmonaire provoqué par le chlore : effets de l'inhalation de monoxyde d'azote". Université Joseph Fourier (Grenoble), 1996. http://www.theses.fr/1996GRE10190.

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L'inhalation de chlore (cl2) provoque des lesions tracheo-bronchiques et un deme pulmonaire de type inflammatoire. Nous avons etabli des modeles experimentaux ex vivo et in vivo pour etudier les mecanismes de cet deme ainsi que l'efficacite therapeutique de l'inhalation de monoxyde d'azote (no). Sur le poumon isole de lapin, nous avons provoque un deme pulmonaire par inhalation de 500 ppm de cl2 pendant 10 minutes. La pression de filtration, la clairance de l'albumine (calb) et le coefficient de filtration (kf = conductivite a l'eau x surface de filtration) ont ete mesures avant et 30 minutes apres administration de cl2. L'inhalation de cl2 a augmente de 200% le kf et la calb, de 100% l'eau extravasculaire (eev), sans modifications de la pression et de la surface de filtration. Ces resultats suggerent que l'deme alveolaire induit par le cl2 est du essentiellement a une augmentation de la permeabilite capillaire et que sa formation est facilitee par la lesion de l'epithelium alveolaire. L'inhalation de 40 ppm de no, 5 minutes apres l'inhalation de cl2, a diminue de 30% l'alteration du kf, de calb et de eev. Le mecanisme d'action du no n'est pas une diminution de la pression de filtration. Il s'agit davantage d'une diminution de l'alteration de la permeabilite capillaire que d'une diminution de la surface de filtration des zones lesees. Chez le chien anesthesie, l'exposition a 250 ppm de cl2 pendant 10 minutes a entraine une augmentation du debit lymphatique pulmonaire par un facteur 2,8, de la clairance des proteines par un facteur 2,5, et de eev par un facteur 1,5. Ce modele in vivo, ou la microcirculation bronchique est fonctionnelle, a montre des differences avec le modele ex vivo, notamment l'importance du spasme bronchique et de l'hypoventilation alveolaire. Le mecanisme de l'deme pulmonaire dans ce modele etait une augmentation a la fois de la permeabilite capillaire et de la pression de filtration

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Lippek, Frank. "Hemmung der Selektin-vermittelten Granulozytenadhäsion durch Fucoidin in der frühen Reperfusionsphase nach Ischämie im Modell der ex-vivo hämoperfundierten Schweineniere". Doctoral thesis, Humboldt-Universität zu Berlin, Medizinische Fakultät - Universitätsklinikum Charité, 2001. http://dx.doi.org/10.18452/14629.

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Der renale Ischämie-/Reperfusionsschaden (IRI) stellt in der Transplantationsmedizin ein grosses Problem dar. Fucoidin, ein potenter Antagonist der Selektin-vermittelten Leukozytenaggregation, verbesserte an der Rattenleber (in einer Konzentration von 360mg/l) das Ausmass der leukozytären Gewebeinfiltration in der frühen Phase nach Ischämie und Reperfusion. In einem Modell der isoliert hämoperfundierten Schweineniere sollte die Wirkung von Fucoidin auf die postischämische Organfunktion untersucht werden. Hierzu wurden 24 Versuche durchgeführt. Dem Blut der Versuchsgruppen wurde vor Beginn der Reperfusion Fucoidin in einer Konzentration von 100 mg/l zugesetzt. Es zeigte sich unter Fucoidin ein signifikanter Abfall des renalen Blutflusses (55 ( 28 vs. 143 ( 97 ml*min-1*100g-1, p
Renal postischemic reperfusion injury constitutes a significant problem after kidney transplantation. The polysaccharide fucoidin (360 mg/l) improves postischemic function in Ratliver, presumably by blocking selectin-mediated leukocyte adhesion. Twelve pairs of ischemic pig kidneys were reperfused in an ex vivo model with autologous blood with or without fucoidin (100 mg/L). Fucoidin resulted in a significant decrease of renal blood flow (55 ( 28 vs. 143 ( 97 mL*min-1*100g-1, p < 0.001) and increased vascular resistance (2.9 ( 2.8 vs. 1.1 ( 1.5 mmHg*mL-1*min-1*100g-1, p < 0.001). Compared to untreated control kidneys significantly more interstitial and intravascular leucocytes were found in fucoidin treated kidneys. Intraglomerular fibrinogen and thrombocytic aggregates were also increased significantly. Granulocytic emboli were present in afferent glomerular arteries of 10/12 fucoidin-treated kidneys and in 2/12 controls (p < 0.001). L-selectin-dependent granulocytic aggregation under shear stress in vitro was prevented by fucoidin in a dose-dependent fashion. However similar concentrations used in reperfused kidneys caused large granulocytic aggregates. The observed formation of embolizing granulocytic aggregates indicates limited effectiveness of fucoidin as an inhibitor of selectin-mediated leukocyte adhesion.

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White, Christopher W. "Resuscitation, preservation, and evaluation of hearts donated after circulatory death: an avenue to expand the donor pool for transplantation". John Wiley and Sons, 2013. http://hdl.handle.net/1993/32171.

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Cardiac transplantation is the treatment of choice for eligible patients with advanced heart failure; however, it is limited by a critical shortage of suitable organs from traditional brain-dead donors. Organs donated following circulatory death (DCD) have been used to successfully expand the pool of organs available for kidney, liver, and lung transplantation; however, concerns regarding the severity of injury sustained by the heart following withdrawal of life sustaining therapy have deterred the clinical transplantation of DCD hearts. Investigations aiming to optimize the resuscitation, preservation, and evaluation of DCD hearts may facilitate the development of an evidence based protocol for DCD heart transplantation that can be translated to the clinical area and expand the donor pool. Therefore, the objectives of this thesis are to develop a clinically relevant large animal model of DCD and gain a greater understanding regarding the physiologic impact of donor extubation on the DCD heart, demonstrate as a ‘proof-of-concept’ that utilizing an approach to donor heart resuscitation, preservation, and evaluation that is tailored to the DCD context can facilitate successful transplantation, and finally to investigate ways to optimize the resuscitation, preservation, and evaluation of DCD hearts for transplantation. The results of this thesis may then be used to inform the development of an evidence-based protocol for DCD heart transplantation that can be translated to the clinical area. The clinical adoption of such a protocol has the potential to expand the donor pool and improve outcomes for patients with end-stage heart failure.
May 2017

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Silva, Natalia Aparecida Nepomuceno da. "Avaliação ex vivo de pulmões de ratos submetidos ao choque hemorrágico: reposição volêmica com Solução Hipertônica x Solução Salina". Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/5/5156/tde-24022016-082523/.

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[Tese]. São Paulo: Faculdade de Medicina, Universidade de São Paulo; 2015. A escassez dos doadores e a má qualidade dos órgãos associados à falta de cuidado em sua manutenção são um grave problema para os grupos de transplante, especialmente para o transplante pulmonar. Um dos principais motivos de recusa para a doação é o edema pulmonar, que pode estar associado a excessiva administração de fluídos no tratamento do choque hemorrágico. Dentre as causa de choque, o choque hemorrágico está frequentemente associado aos doadores vítimas de traumatismo. Uma das estratégias clínicas aplicadas para a recuperação do choque hemorrágico é a administração precoce de fluídos e produtos sanguíneos. O uso de soluções cristalóides como Soluções Isotônicas e Hipertônicas promove a expansão volêmica intravascular restabelecendo a pressão arterial média. A ressuscitação volêmica com cristalóide isotônico requer administração de alta quantidade de volume, em contrapartida a solução hipertônica a 7,5% mostra uma redução de três a quatro vezes no volume. Na tentativa de aumentar a oferta de doadores de pulmão nossa hipótese baseia-se na realização de um tratamento com solução Salina Hipertônica em doadores com choque hemorrágico. O objetivo deste trabalho é avaliar pulmões de ratos submetidos ao choque hemorrágico tratados com solução hipertônica comparando com a solução salina. Oitenta ratos foram divididos em 4 grupos: Sham (Sham n=20); Choque (Choque n=20); SS ( Choque + Solução Salina n=20) e SH ( Choque + Solução Hipertônica n=20). Após anestesia, os animais foram submetidos à cateterização da artéria e veia femoral para registro de pressão arterial média (PAM) e obtenção do choque hemorrágico. No grupo Sham foi realizada a monitorização dos parâmetros, nos grupos Choque, SS e SH obtenção do choque hemorrágico (40 mmHg), e tratamento de solução hipertônica (4 ml/Kg) no grupo SH e solução salina (33 ml/kg) no grupo SS. Após 120 minutos, 10 blocos cardiopulmonares de cada grupo foram encaminhados ao sistema de perfusão ex vivo Harvard Apparatus IL-2 Isolated Perfused e avaliados durante 60 minutos, os outros 10 blocos dos grupo foram destinados a dosagem de citocinaTnf-alfa, IL 1-beta e quantificação de neutrófilo. Na avaliação ex vivo o parâmetro que apresentou diferença estatística significante foi a Pressão da artéria Pulmonar (PAP) do grupo Choque em relação aos demais grupos (p < 0,05). A dosagem de Tnf-alfa no grupo choque foi superior a todos os grupo (p < 0,05). Em relação a contagem de neutrófilos o grupo tratado com solução hipertônica e solução isotônica apresentaram resultado igual ao grupo Sham,o grupo choque apresentou infiltrado neutrofílico superior aos demais grupos (p < 0,05). Concluímos que os pulmões de ratos submetidos ao choque hemorrágico tratados com solução hipertônica apresentam parâmetros de mecânica ventilatória semelhante e recuperação hemodinâmica melhor do que os animais tratados com solução salina a 0,9%. Além disso, reduz os parâmetros inflamatórios dos animais submetidos ao choque hemorrágico
The lack of donors and poor quality of organs associated to poor organ handling is a serious problem for transplantation groups, especially for lung transplantation. Pulmonary edema is one of the main reasons for donation rejection, which may be associated to excessive fluid administration in the treatment of hemorrhagic shock. Of the causes of shock, hemorrhagic shock is frequently associated to donors who are victims of trauma. One of the clinical strategies used in the recovery of hemorrhagic shock is the early administration of fluids and blood products. The use of crystalloid solutions such as Isotonic and Hypertonic Solutions promote intravascular volume expansion thus reestablishing mean blood pressure. Volume resuscitation with isotonic crystalloid requires the administration of a high amount of volume, whereas hypertonic solution 7.5% produces a three or four fold volume reduction. In an attempt to increase the offer of lung donors, our hypothesis is based on a treatment with hypertonic saline solution in donors with hemorrhagic shock. The objective of this study is to evaluate the lungs of rats undergoing hemorrhagic shock treated with hypertonic solution compared to saline solution. Eighty rats were divided into 4 groups: Sham (Sham, n=20); Shock (Shock, n=20); SS (Shock + Saline Solution, n=20) and SH ( Shock + Hypertonic Solution, n=20). After anesthesia, animals were submitted to catheterization of the femoral artery and vein to record mean arterial pressure (MAP) andto obtain hemorrhagic shock. In the Sham group the different parameters were monitored, in the Shock, SS and SH groups hemorrhagic shock was obtained (40 mmHg). The SH group received the hypertonic solution (4 ml/Kg) and the SS group received saline solution (33 ml/kg). After 120 minutes, 10 cardiopulmonary blocks of each group were evaluated by the ex vivo Harvard Apparatus IL-2 Isolated Perfused system for 60 minutes, the other 10 blocks were had cytokine TNF-alpha and IL 1-beta measurement and neutrophil quantification performed. In the ex vivo evaluation, pulmonary artery pressure (PAP) was the variable with statistically significant difference (p < 0.05) in the shock group when compared to the other groups. TNF-alfa measurement in the shock group was higher than in all of the other groups (p < 0.05). Neutrophil counts in the groups treated with hypertonic solution and isotonic solution were similar to the Sham group. The shock group had higher neutrophil infiltrate values than the other groups (p < 0.05). We conclude that the lungs of rats undergoing hemorrhagic shock treated with hypertonic solution had similar mechanical ventilation parameters and better hemodynamic recovery than the animals treated with 0.9% saline solution. Furthermore, it reduced the inflammatory parameters of animals undergoing hemorrhagic shock

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Yates, Phillip James. "The relative effects of leukocyte depletion and nitric oxide modulation in an ex-vivo porcine normothermic perfusion model of donation after cardiac death in the kidney". Thesis, University of Leicester, 2010. http://hdl.handle.net/2381/8608.

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Introduction: The shortage of donors necessitates the use of organs from donation after cardiac death (DCD) donors. These organs demonstrate a high rate of delayed graft function (DGF) and primary non-function (PNF) when compared to those from non-DCD donors. DGF and PNF are associated with shorter graft survival times. Reperfusion injury (RI) is important in the aetiology of DGF and PNF. The roles of leukocytes and nitric oxide (NO) are pivotal in the generation of RI. The aim of this study was to assess the effect on RI of modulating leukocyte and NO levels at the time of reperfusion. Methods: This study utilised a porcine extra-corporeal normothermic perfusion model of RI. Kidneys were perfused with whole (WB) or leukocyte depleted blood (LDB) alone, or with an inducible nitric oxide (iNOS) inhibitor or NO donor. This model allows the collection of haemodynamic and functional data, as well as plasma and urine for biochemical analysis. Results: Kidneys reperfused with LDB demonstrated improved blood flow and function compared to those reperfused with WB. Initial blood flow and function in the iNOS supplemented groups was worse than in the WB/LDB perfused groups, but improved in the NO donor groups. Late blood flow plateaued in the NO donor groups but improved in the iNOS supplemented WB group. LDB and iNOS supplementation together gave poor blood flow and function throughout reperfusion. Conclusion: Depletion of leukocytes abrogates the no-reflow phenomenon and reduces the oxidative stress caused by white cell infiltration, thereby improving blood flow and function. The effects of nitric oxide and its inhibition on the endothelium, glomerulus and renal tubule during initial reperfusion are dependent upon the phase of reperfusion. Early benefits to blood flow by NO supplementation are offset by the generation of NO free radicals later after reperfusion.

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ROGGIO, DOROTEA. "The use of Human Liver Stem cells-Extracellular Vesicles (HLSC-EVs) as a biological treatment to recondition marginal rat livers during ex-vivo normothermic perfusion (NMP)". Doctoral thesis, Politecnico di Torino, 2020. http://hdl.handle.net/11583/2836792.

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Rößner, Jana [Verfasser], Ekkehard [Akademischer Betreuer] Schleußner, James Friedrich [Akademischer Betreuer] Beck e Torsten [Akademischer Betreuer] Steinmetzer. "Einfluss von No-Donoren auf den plazentaren Stoffwechsel während der zweiseitigen ex vivo Perfusion reifer Plazentakotyledone am Beispiel von Pentaerithrityltetranitrat / Jana Rößner. Gutachter: Ekkehard Schleußner ; James Friedrich Beck ; Torsten Steinmetzer". Jena : Thüringer Universitäts- und Landesbibliothek Jena, 2013. http://d-nb.info/103407380X/34.

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Mourmoura, Evangelia. "Les effets de l'augmentation de la masse adipeuse sur la fonction cardiovasculaire ex vivo en fonction du stress oxydant et de la fonction mitochondriale : rôle du vieillissement du régime alimentaire". Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00870794.

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Le surpoids et l'obésité, en constante augmentation à l'échelle mondiale à un rythme exponentiel, conduit au développement du syndrome métabolique et du diabète de type 2. Plusieurs études ont mis en évidence l'association entre l'excès de masse grasse, en particulier dans la région abdominale, et le développement des maladies cardiovasculaires. Une telle augmentation de masse grasse corporelle caractérise le vieillissement normal, qui est considéré per se comme un facteur de risque majeur pour les maladies cardiovasculaires. De plus, dans le monde industrialisé, l'incidence des maladies cardiovasculaires est encore plus élevée et fortement liée aux habitudes occidentales (régimes obésogènes, sédentarité) qui contribuent à l'accumulation de la graisse abdominale. L'objectif général de ce travail consiste à suivre les changements corporels qui surviennent entre la jeunesse et l'âge moyen où commence à survenir les complications cardio-vasculaires et à savoir comment l'obésité induite par l'alimentation peut modifier ces aspects. Dans un premier temps, nous avons montré que les coeurs des rats Wistar d'âge moyen sont caractérisés par une moindre restauration de l'activité mécanique cardiaque au cours de la réperfusion post-ischémique en raison de perturbations de la perfusion coronaire et d'une insuffisance de l'apport en oxygène. La présence d'un stress oxydant systémique suite à l'augmentation de la masse grasse survenant entre la jeunesse et l'âge adulte est également en cause. Une diminution progressive de la dilatation endothélium-dépendante des microvaisseaux coronaires est également observé avec le vieillissement, ce qui résulte d'une évolution différentielle du comportement fonctionnel des cellules endothéliales et musculaires lisses apparemment liée au métabolisme énergétique et au stress oxydant. L'obésité induite par un régime riche en graisse provoque un certain nombre de modifications corporelles, métaboliques et cardiovasculaires au cours de cette période du vieillissement. L'excès de masse grasse abdominale induit une augmentation du stress oxydant aux niveaux systémique, cytosolique et mitochondrial accompagné par des altérations biochimiques concernant le métabolisme du glucose et les niveaux plasmatiques de cholestérol et de triglycérides. L'obésité induite par une hyperphagie et la présence d'un diabète de type 2 chez les rats Zucker obèses diabétiques provoque également une insulino-résistance sévère. Ces deux modèles d'obésité sont caractérisés par une diminution de la fonction cardiaque ex vivo liée au métabolisme énergétique mitochondrial et au stress oxydant. En outre, ils sont tous les deux caractérisés par une adaptation des microvaisseaux coronaires dont la réactivité est augmentée dans le cas de régime riche en graisse et maintenue dans le cas du diabète. Ces adaptations sont dues à des mécanismes différents dans les deux modèles d'obésité. Elles permettent de mieux répondre aux exigences métaboliques élevées liées à l'obésité. En conclusion, notre travail montre que les caractéristiques corporelles et métaboliques, le métabolisme énergétique mitochondrial, la fonction cardiaque et la réactivité coronaire sont modifiés lors du vieillissement dans les conditions normales ou obésogènes. Ces résultats encouragent la recherche ultérieure des mécanismes mis en jeu. Les interventions visant à réduire la masse grasse, qu'elle soit spontanément accrue par l'âge ou qu'elle résulte du régime alimentaire, seraient d'un grand intérêt pour retarder les complications cardiovasculaires.

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Zu, Theresah Nom Korbieh. "Phenotypic and Metabolic Profiling of Biological Samples in Near Real-Time Using Raman Spectroscopy". Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/65153.

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Raman spectroscopy, together with multivariate statistical analyses, has proven to be a near real-time analytical technique capable of phenotyping cells, tissues and organs. This dissertation will show exclusively the application of the Raman spectroscopy phenotypic profiling method to; (i) microbial toxicity, (ii) ex-vivo organ perfusion, and (iii) subcellular location targeting. Real-time analytical methods for monitoring living biological systems will enable study of the physiological changes associated with growth, genetic manipulations, and adverse environmental conditions. Most existing analytical methods (NMR exempt), though highly accurate, must be performed off-line and most require destruction of the studied sample. These attributes make these methodologies less desirable to the study of physiological changes of cells, tissues, and organs. In this work, Raman spectroscopy has been identified and shown to be a good candidate for real-time analysis mainly because it can be performed: (i) in near real-time, (ii) non-destructively and with minimal sample preparation, (iii) through a glass barrier (i.e., can be performed in situ), and (iv) with minimal spectral interference from water. Here, Raman spectroscopy was used in combination with multivariate statistics to analyze the differing toxic effects of 4-C chain alcohols on E. coli. Good correlations were established between Raman spectra and off-line analytical techniques used to measure: (i) saturated, unsaturated, and cyclopropane fatty acids; (ii) amino acid composition of total protein; and (iii) cell membrane fluidity. Also, Raman 'fingerprint' analysis was used to discriminate among different phenotypic responses of cells. In addition, this methodology was applied to analyze perfusates of organs maintained by the VasoWave® organ perfusion system. Raman fingerprints can be used to assess organ health, and it is believed this data can be used to inform decisions such as whether or not to transplant an organ. Finally, molecular biology techniques were used to design and produce specific protein targets harboring a silver binding domain fusion, which upon release migrate to specific subcellular locations. By employing the related technique of surface-enhanced Raman scattering (SERS), which produces a highly amplified Raman signal in the presence of metallic nanoparticle substrates (e.g., silver nanoparticles), different regions of the E. coli cell structure were studied. The target regions studied by the technique included: (i) outer cell membrane, (ii) periplasm, and the (iii) cytoplasm.
Ph. D.

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Seewald, Maria Sabine [Verfasser], Jens [Gutachter] Wippermann e Gábor [Gutachter] Szabó. "Investigations of pharmacological pre- and posttreatments with Omegaven and ATP in a four-chamber isolated working swine heart model : implications for cardiac interventions, cardiac transplantation and ex vivo perfusion systems / Maria Sabine Seewald ; Gutachter: Jens Wippermann, Gábor Szabó". Magdeburg : Universitätsbibliothek Otto-von-Guericke-Universität, 2020. http://d-nb.info/1228071594/34.

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Lotriet, Cornelius Jacob. "Investigations on the respiratory effects of ozone in the rodent / Cornelius Jacon Lotriet". Thesis, North-West University, 2010. http://hdl.handle.net/10394/4650.

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Ozone, being an unstable molecule, is believed to be one of the strongest oxidant agents known to man. Rapid growth in the application of ozone — both as disinfectant and as form of alternative medicine — led to questions about the effects of uncontrolled ozone exposure and inhalation, whether intentional or unintentional, on the human body. This study specifically focussed on examining, identifying and substantiating the respiratory effect of acute exposure (10 min or less) to considerably higher ozone concentrations than reported on before (19.5 ± 0.5 ppm). Respiratory tissue of rodents (Duncan–Hartley guinea pigs of both sexes and Male Wistar rats) was subjected to ozone by utilising three distinctly diverse models of ozone introduction: (a) in vitro exposure, (b) in vivo exposure, and (c) ex vivo by employing an isolated lung perfusion model which allows for real–time, breath–by–breath data acquisition of ozone’s effect on respiratory mechanics. The effect of ozone on the isolated trachea in the presence of various drugs with well–known effects, including methacholine, isoproterenol and ascorbic acid was also examined. The results found in this study identified two direct effects on the isolated trachea due to ozone exposure: (1) a definite contraction of the isolated trachea immediately after exposure to ozone, and (2) a clearly visible and significant hyper responsiveness of the isolated trachea to irritants, e.g. methacholine. Although ozone has a negative effect on the trachea, it was concluded that ozone has no adverse effect on muscarinic acetylcholine receptors. An apparent EC50 value of ozone on the trachea was established by two different methods as (2.77 ± 0.02) x 10–3 M and (2.10 ± 0.03) x 10–3 M, respectively. Ozone furthermore displayed an attenuation of the beneficial pharmacological response of –sympathomimetic drugs (i.e. isoproterenol), while isoproterenol itself has a relaxing effect on the ozone–induced contraction of the isolated trachea. Indomethacin pre–treatment of isolated tracheal tissue significantly (77%) reduced the ozone–induced contraction of tracheal smooth muscle, suggesting that COXproducts of arachidonic acid play a prominent role in the development of pulmonary function decrements consequent to acute high–dose ozone exposure. Ascorbic acid exhibited a meaningful prophylactic effect on ozone–induced contraction of both isolated tracheal tissue and in the isolated lung perfusion model, emphasising the major role antioxidants play in both the epithelium lining fluid (ELF) of the respiratory system and in plasma throughout the body in protecting against the destructive effects of ozone. Surprisingly, pre–treatment with ascorbic acid did not prevent hyper responsiveness of isolated tracheal preparations to methacholine after a 10 min ozone (19.5 ± 0.5 ppm) exposure. In the lung perfusion model, the presence of ascorbic acid in the perfusion medium did, however, significantly reduce the magnitude and rate of decline in lung compliance after ozone exposure (46% decline with ascorbic acid versus 96% in the control study without ascorbic acid). Examination of a lung perfusion model exposed to ozone (19.5 ± 0.5 ppm O3; 5 seconds) presented a significant decline in lung compliance (95.6% within 2 min), tidal volume (70%) and maximum inspiratory flow (71.2%), with an ensuing reduction in lung elasticity and severely hampered breathing pattern. Microscopic examination after acute high–dose inhalation studies did not display any significant cellular damage, oedema or inflammation after acute high–dose ozone exposure. This suggests that significant cellular injury and inflammation is possibly not the causative factor of early breathing difficulty experienced after acute high–dose ozone inhalation, as these symptoms and particularly the result of inflammatory precursors, is believed to probably only set in at a later stage. Although the potential advantages of ozone in certain fields of medicine are not disputed, ozone, depending on its concentration and cumulative dose, can be either therapeutic or toxic. Observations in this study emphasised that even short bursts of high–dose ozone inhalation have deleterious effects on respiratory health and care should be taken not to jump to conclusions regarding ozone’s medical application without relevant scientific evidence. It must be stressed that high–dose inhalation of ozone should be avoided at all cost – especially by those with existing airway diseases.
Thesis (Ph.D. (Pharmacology))--North-West University, Potchefstroom Campus, 2011.

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Hassan, Sarah [Verfasser], Olaf [Akademischer Betreuer] Dammann e Christiane [Akademischer Betreuer] Dammann. "Simulation of intra-amniotic infection and the fetal inflammatory response in a novel ex-vivo human umbilical cord perfusion model / Sarah Hassan. Klinik für Frauenheilkunde und Geburtshilfe und dem Zentrum Kinderheilkunde und Jugendmedizin, Abteilung Pädiatrische Pneumologie und Neonatologie der Medizinischen Hochschule Hannover. Betreuer: Olaf Dammann ; Christiane Dammann". Hannover : Bibliothek der Medizinischen Hochschule Hannover, 2010. http://d-nb.info/1010308742/34.

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Kuan, Kean Guan. "Extracorporeal normothermic pancreas perfusion". Thesis, 2016. http://hdl.handle.net/2440/102708.

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Pancreas and islet transplantation are important treatment options for insulin dependent diabetes. However, one of the main challenges in pancreas and islet transplantation lies in organ (pancreas) preservation. Ischaemic injury post-retrieval causes significant damage the organ function and reduction in islet yield. It was hypothesised that extracorporeal normothermic perfusion of the pancreas would improve graft function post transplantation and pancreatic islet isolation when compared to traditional methods of organ preservation. The aims and objectives of the project included: • Conducting a systematic review of the literature in extracorporeal machine perfusion of the pancreas • Establishing an extracorporeal normothermic perfusion model of the porcine pancreas • Comparing the addition of kidney to the circuit of extracorporeal pancreas perfusion model A thorough systematic review of the available literature concluded the potential benefits of machine perfusion in pancreas preservation. Important insight into the experimental setup, perfusion parameters and vital outcome measures was also attained. A model of normothermic hemo-perfusion of the porcine pancreas with and without addition of the kidney as a dialysis organ was subsequently established. The organs were perfused for 120 minutes with stable perfusion parameters but sub-optimal acid-base environment. Addition of the kidney did not result in significant improvement of the acid-base environment.
Thesis (M.Phil.) (Research by Publication) -- University of Adelaide, School of Medicine, 2016.

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Yeung, Jonathan. "Ex vivo Lung Perfusion: A Platform for Lung Evaluation and Repair". Thesis, 2011. http://hdl.handle.net/1807/31987.

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Lung transplantation is a life-saving therapy for patients suffering from end-stage lung disease; however, the majority of donor lungs are injured and attempts to transplant them results in a high risk of primary graft dysfunction in the recipient, a type of severe acute lung injury. Previously, a novel method of lung preservation known as ex vivo lung perfusion (EVLP) has been developed in which donor lungs are continuously perfused and ventilated at normothermia using a protective strategy. Donor lungs have been shown to tolerate at least 12 h of preservation in this manner without the accrual of injury. Hence, EVLP could act as a platform on which injured donor lungs could potentially be evaluated and repaired. To explore this concept, we utilized interleukin-10 (IL-10), an anti-inflammatory cytokine, as a prototypical drug for ex vivo delivery. Because IL-10 protein has a prolonged half-life during EVLP, we delivered recombinant IL-10 by the intravascular and intratracheal routes to clinically-rejected injured human lungs. Intratracheal delivery resulted in elevated levels of IL-10 in both tissue and perfusate whereas intravascular delivery resulted in elevated levels of IL-10 only in the perfusate over 12 h of EVLP. There was, however, no beneficial effect to either lung function or lung inflammation. This was thought to be a result of intratracheally delivered IL-10 leaking out into the perfusate where it may not be biologically active. Constant IL-10 production within the lung tissue could be achieved using a gene therapy approach. Thus, we subsequently explored the delivery of IL-10 by adenoviral gene therapy during EVLP. Ex vivo administered intratracheal adenoviral gene therapy could increase transgene protein levels within the lung. More importantly, it did so with less vector-associated inflammation when compared to in vivo delivery of adenoviral gene therapy. Having explored drug delivery, we sought to develop a large animal injury model on which to test ex vivo therapies. Given that the majority of organ donors are brain dead and therefore exposed to the injurious sequelae resulting from brain death, we developed a brain-death injury model in pig. Use of EVLP as a platform for repair necessitates an accurate recognition of both lung injury and lung improvement during EVLP. Thus, we utilized this injury model to explore the profile of physiological parameters when an injured lung is perfused during EVLP. Because of the alteration of the PO2 to oxygen content relationship of an acellular perfusate, we found that PaO2 changes are less dramatic than in the in vivo situation. However, as injured lungs begin to become edematous, the mechanical effects on the lung by the increased water content can be measured by corresponding falls in compliance and increases in airway pressure. Overall, use of EVLP demonstrates promise for reducing the organ shortage currently prevalent in clinical lung transplantation. Improved evaluation will instill confidence in transplant clinicians to transplant previously questionable organs. Lungs which prove to be injured during evaluation can potentially be repaired using IL-10 therapy as explored herein or with other therapies using the delivery methods described.

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Matlow, Jeremy. "The Transfer of Ethyl Glucuronide in the Dually Perfused Ex Vivo Placental Perfusion Model: Implications for Alcohol Screening during Pregnancy". Thesis, 2012. http://hdl.handle.net/1807/33434.

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Alcohol consumption during pregnancy can lead to Fetal Alcohol Spectrum Disorder, and because maternal self-reports are often unreliable, a biomarker of alcohol use during pregnancy is needed to accurately determine fetal exposure. Ethyl glucuronide (EtG) is a direct metabolite of ethanol that has been detected in the meconium of infants born to mothers who consumed alcohol during pregnancy. In the current study, a method was developed and validated for EtG detection in placental perfusate and tissue using gas chromatography-mass spectrometry. Subsequently, the ex vivo human placental perfusion model was used to investigate whether EtG crosses the human placenta. The validated GC-MS method showed sufficient sensitivity in detecting EtG in placental perfusate and tissue. EtG crossed the placenta slowly and transfer was incomplete after 3 hours of perfusion. EtG appears to cross the human placenta and, hence, to represent both maternal and fetal exposure to alcohol.

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Vincent, Geneviève. "Phénotypage métabolique du coeur sain et malade basé sur l'analyse d'isotopomères de masse marqués au carbone 13 : implications du citrate". Thèse, 2003. http://hdl.handle.net/1866/14768.

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Gélinas, Roselle. "Altérations du métabolisme cardiaque associées à des désordres génétiques de l’oxydation des acides gras à chaîne longue chez la souris". Thèse, 2011. http://hdl.handle.net/1866/6909.

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Bien que le changement dans le choix des substrats énergétiques des acides gras (AGs) vers les glucides soit considéré comme bénéfique pour le cœur insuffisant, il n’est pas clair à savoir pourquoi les patients atteints de désordres de la β-oxydation (β-OX) des AGs à chaîne longue (AGCLs) développent des troubles du rythme et des cardiomyopathies. De plus, le traitement actuel ne permet pas de prévenir l’apparition du phénotype clinique chez tous les patients, spécifiquement en condition de jeûne ou de stress. Ainsi, plusieurs modèles de souris déficientes pour des enzymes impliquées dans l’oxydation des acides gras ont été développés de manière à améliorer les connaissances de la maladie ainsi que les traitements offerts aux patients. À cet égard, cette étude vise à évaluer le phénotype métabolique et fonctionnel des cœurs de souris déficientes pour le récepteur activé de la prolifération des peroxysomes-α (PPARα), un facteur de transcription des gènes impliqués notamment dans la β-OX des AGs, et pour la déshydrogénase des acyl-CoA à très longue chaîne (very-long chain acyl-CoA dehydrogenase, VLCAD), le déficit de l’oxydation des AGCLs le plus commun chez l’humain. L’approche expérimentale utilisée comprend plusieurs techniques dont (i) la perfusion ex vivo de cœur de souris au travail combinée à l’utilisation de substrats marqués au carbone 13 (13C) et à l’analyse par chromatographie gazeuse-spectrométrie de masse (GCMS), (ii) l’analyse de l’expression génique par qPCR et (iii) l’analyse de l’activité électrique du cœur in vivo par télémétrie. De manière inattendue, les résultats de cette étude menée chez la souris ont permis de mettre en évidence que des déficits pour des protéines impliquées dans l’oxydation des AGCLs sont associés à des altérations du métabolisme (i) des glucides, (ii) des AGs polyinsaturés (AGPIs), et (iii) mitochondrial, incluant l’anaplérose, en plus d’être liés à des désordres de la fonction électrique du cœur, à savoir une prolongation du segment QTc. Pris dans leur ensemble, les résultats de cette thèse pourraient servir à l’élaboration de nouvelles interventions métaboliques destinées à améliorer les traitements possibles et donc, la qualité de vie des patients atteints de désordres héréditaires de la β-OX des AGCLs.
While a shift from fatty acids to carbohydrate is considered beneficial for the failing heart, it is unclear why patients with fatty acid oxidation disorders present clinical manifestations such as cardiomyopathy, arrhythmia and conduction defects. Unfortunately, the current nutritional treatment for these patients is limited in its ability to prevent these symptoms, especially under fasting and stress conditions. Many mouse models of fatty acid oxidation deficiency have been developed to improve the knowledge of the disease and the treatment of these patients. In this regard, this study aims to characterize the metabolic and functional phenotype of hearts from mice that are deficient for the peroxisome proliferator-activated receptor α, a transcription factor for gene involved in fatty acid oxidation, and very long chain acyl-CoA dehydrogenase, the most common inherited long chain fatty acid oxidation disorder in human, under various conditions. In this study, numerous approaches have been used, which includes validated experimental paradigms, namely, (i) ex vivo heart perfusion in the working mode with concomitant evaluation of myocardial contractility and metabolic fluxes, employing 13C-labeled substrates combined with mass isotopomer analysis by gas chromatography coupled to mass spectrometry, (ii) gene expression analysis by qPCR and (iii) electrocardiogram monitoring in vivo by telemetry. Unexpectedly, results from the present thesis demonstrate that fatty acid oxidation disorders cause alterations in metabolism of (i) carbohydrates (ii) polyunsaturated fatty acids of the omega-3 type, specifically docosahaexanoic acid, and (iii) mitochondria including anaplerosis, in addition to lead to functional abnormalities, namely a prolongation of the QT interval. Altogether, results from this thesis could contribute to new metabolic therapy development to improve the quality of life of the patients with inherited long chain fatty acid oxidation disorder.

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Tesi sul tema "Perfusion pulmonaire ex vivo"

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