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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
451

Etude des facteurs viraux et cellulaires impliqués dans l'échappement du virus de l'hépatite C au cours de la transplantation hépatique / Study of viral and cellular factors involved in hepatitis C virus escape during liver transplantation

Fauvelle, Catherine 02 December 2013 (has links)
La cirrhose et le carcinome hépatocellulaire liés au virus de l’hépatite C (HCV) sont des indications majeures de transplantation hépatique. La réinfection du greffon par le HCV est systématique et sans moyen de prévention. Les mécanismes par lesquels le virus échappe au système immunitaire afin de réinfecter le greffon sont mal connus. Ce travail de thèse a permis d’identifier de nouveaux mécanismes et des déterminants clés impliqués dans la persistance virale. Nous avons identifié que l’utilisation des facteurs d’entrée cellulaires par le HCV évolue simultanément avec ses capacités d’échappement aux nAbs, et démontré qu’apo E est un composant clé des lipoparticules virales intervenant dans la persistance du HCV. L’identification de nouveaux facteurs viraux et cellulaires impliqués dans l’échappement viral, apporte de nouvelles perspectives dans le développement de nouvelles stratégies de prévention de la réinfection ainsi que dans le développement d’un vaccin prophylactique. / Hepatitis C virus (HCV)-cirrhosis and HCC are leading indications for liver transplantation. Reinfection of the liver graft is universal and no way of prevention exists. Mechanisms employed by HCV to evade the immune system and reinfect the liver graft are unknown. This thesis work identified new mechanisms and key determinants involved in viral persistence. Weidentified a novel clinically and therapeutically important mechanism of viral evasion, where coevolution simultaneously occurs between cellular entry factor use and escape from neutralization. We also discovered that virus-apoE interaction is unique mechanism of viral evasion from neutralizing antibodies. Identification of new viral and host factors involved in viral escape paves the way in the development of new prevention strategies and prophylactic vaccine.
452

Ação da matriz inorgânica de osso bovino (Bonefill®) na neoformação óssea em ratos submetidos ao alcoolismo experimental: análise histológica e morfométrica / Action of inorganic bovine bone Matrix (Bonefill®) on bone formation in rats submitted to experimental alcoholism: histological and morphometric analysis

Iris Jasmin Santos German Borgo 17 March 2016 (has links)
O desequilíbio no turnover ósseo decorrente dos efeitos do alcoolismo crônico está relacionado à apoptose dos osteócitos, diminuição da espessura do osso medular e cortical e pelas alterações na atividade e diferenciação de osteoblastos. Devido à necessidade de tratamentos regenerativos e reconstrutivos associado ao alcoolismo, os xenoenxertos tem providenciado uma possibilidade terapêutica como material de preenchimento de defeitos ósseos. Em vista disso, este trabalho teve como objetivo analisar o comportamento do biomaterial Bonefill® em defeitos críticos realizados em calvária de ratos, comparar a interferência do alcoolismo experimental na neoformação óssea, além de avaliar a influência do tipo de dieta líquida sobre a massa corporal dos animais. Foram utilizados 40 ratos machos (Rattus norvegicus) da linhagem Wistar, com 60 dias de idade, separados aleatoriamente em Grupo Controle (GC) os animais receberam água como dieta líquida e Grupo Experimental (GE) os animais receberam etanol a 25%, cada grupo composto por 20 ratos. O GC foi sub-dividido em GAC (Grupo Água Coágulo) correspondente ao defeito direito na calota craniana do animal e GAB (Grupo Água Biomaterial), defeito do lado esquerdo do animal. O GE foi sub-dividido em GEC (Grupo Etanol Coágulo) correspondente ao defeito direito da calota craniana e GEB (Grupo Etanol Biomaterial) defeito do lado esquerdo do animal. Foi realizada uma osteotomia circular de 5 mm de diâmetro no osso parietal direito e esquerdo. Os defeitos GAC e GEC foram preenchidos com coágulo sanguíneo e os defeitos GAB e GEB com osso bovino cortical inorgânico. Cinco animais de cada grupo foram eutanasiados nos períodos de 10, 20, 40 e 60 dias pós-cirúrgico. Os resultados da análise histológica mostraram que no período de 10 dias, no GAB e GEB as partículas do enxerto ósseo estavam circundadas por tecido de granulação e células inflamatórias, apresentou uma pequena formação de osso imaturo principalmente nas margens do defeito. No período de 20 dias foi obsevado presença de vasos sanguíneos e no GAB e GEB algumas partículas parcialmente circundadas por tecido ósseo neoformado. Os períodos de 40 e 60 dias exibiram áreas de formação óssea nas margens e ao redor de algumas partículas. O osso neoformado encontrava-se em um estágio mais avançado de remodelação, porém sem preenchimento completo do defeito e sem sinais de reabsorção da superfície do biomaterial. Na análise histomofométrica o percentual de formação óssea entre o GAC versus GEC e GAB versus GEB, para cada período experimental, não apontou diferença estatisticamente significante. Com relação à massa corporal o GC, nos períodos de 20, 40 e 60 dias pós-cirurgia a massa corporal aumentou, 7,9%, 6,6% e 14,1%, respectivamente. No GE ocorreu uma perda de 9,2% da massa corporal após 10 dias da cirurgia, e aos 40 e 60 dias ocorreu ganho de massa corporal de respectivamente 5,9% e 6,4% nos animais. Conclui-se que o biomaterial Bonefill® não promoveu uma maior neoformação óssea em defeitos críticos; a dieta alcoólica não atingiu os seus efeitos nocivos na formação óssea, e a dieta líquida de etanol, quando comparada à de água, interferiu negativamente na massa corporal dos animais. / The imbalance in bone turnover resulting from the effects of chronic alcoholism is related to apoptosis of osteocytes, decrease of trabecular and cortical bone thickness and changes in activity and differentiation of osteoblasts. Due to the need for regenerative and reconstructive treatments associated with alcoholism, xenografts has provided a therapeutic possibility as a filling material of bone defects. Therefore, the aims of this study were to analyze the Bonefill® biomaterial behavior in critical defects created on the calvaria of rats; to compare the interference of experimental alcoholism in bone formation, as well as to evaluate the influence of 2 type of liquid diet on animal body weight. 40 male Wistar rats were used (Rattus norvegicus), with 60 days of age. The rats were randomly separated into Control Group (CG, nº = 20), which received water as liquid diet and Experimental Group (EG, nº = 20), these rats consumed ethanol 25%. CG was subdivided into WCG (Water Clot Group), corresponding to the right calvaria defect and WBG (Water Biomaterial Group), left side defect of the calvaria. EG was subdivided into ECG (Ethanol Clot Group), corresponding to the right calvaria defect and EBG (Ethanol Biomaterial Group), left side defect of the calvaria. A circle osteotomy of 5 mm in diameter was performed in the right and left parietal bone. The bone defects in WCG and ECG were filled with blood clot and the defects in WBG and EBG were filled with inorganic bovine bone. 5 animals from each group were euthanized at periods of 10, 20, 40 and 60 days after surgery. The histological analysis showed that at 10 days, WBG and EBG, the particles of bone graft were surrounded by granulation tissue and inflammatory cells, it also showed a small immature bone formation mainly at the margins of the defects. At 20 days it was observed blood vessels in WBG and EBG and some graft particles partially surrounded by new bone. At 40 and 60 days it was exhibited some areas of bone formation at the margins and around a few particles. The newly formed bone was in a more advanced stage of bone remodeling, however it did not showed neither complete filling nor signs of resorption of the biomaterial surface. Histomorphometric analysis on the percentage of bone formation between WCG versus ECG and WBG versus EBG, for each trial period, showed no statistical significant difference. Regarding the body mass CG, at 20, 40 and 60 days the body mass increased 7.9%, 6.6% and 14.1%, respectively. The EG had a loss of body weight of 9.2% after 10 days of surgery and at 40 and 60 days it showed a body mass gain of 5.9% and 6.4%, respectively. It can be concluded that Bonefill® did not promote an increase bone formation in critical defects; the alcohol diet did not achieve its adverse effects on bone formation, and the liquid diet containing ethanol, compared to the liquid water diet had a negative effect on animal body weight.
453

Análise comparativa entre o aloenxerto ósseo liofilizado, aloenxerto ósseo congelado e enxerto autógeno: estudo histológico em coelhos / Comparative analysis of demineralized freeze-dried bone, fresh frozen bone allograft and autogenous bone graft: a histologic study in rabbits

Júlio Leonardo Oliveira Lima 06 December 2013 (has links)
Considerando as diferentes aplicações clínicas dos enxertos ósseos nas reconstruções alveolares e a dificuldade de se obter ganhos ósseos em altura, o presente estudo avaliou do ponto de vista histológico a integração do enxerto autógeno (AU), do aloenxerto ósseo liofilizado desmineralizado (ALD), do aloenxerto ósseo congelado mineralizado (ACM) e do coágulo sanguíneo (CO) em um modelo de regeneração óssea vertical. Foram utilizados nove coelhos, sendo um animal doador primário de enxertos ósseos e oito animais submetidos a um modelo de regeneração óssea guiada (ROG), onde 32 cilindros de titânio foram fixados na calota craniana e preenchidos aleatoriamente com AU, ALD, ACM e CO. Após 13 semanas, os animais sofreram eutanásia e o conteúdo dos cilindros submetido à avaliação histológica e histomorfometrica para quantificar a área total de tecido neoformado (AT), o osso neoformado (ON) e o remanescente do material enxertado (MR). Os dados foram submetidos aos testes t-Student e Mann-Whitney com nível de significância de 5%. Os resultados mostraram que em relação à AT os valores médios foram significantes para ACM e ALD e seguiram a seguinte relação: ACM = ALD > AU > CO. Para a variável neoformação óssea as intervenções ALD e ACM mostraram maior quantidade de tecido ósseo formado do que as que empregaram osso autógeno ou coágulo. Já em relação à MR, a média da variável obedeceu à relação: ACM > ALD = AU = CO (valores-p < 5%). Todas as intervenções apresentaram médias mais significativas de crescimento tecidual nas regiões mais próximas ao leito receptor. Foi possível concluir que os aloenxertos podem ser considerados soluções adequadas para o crescimento ósseo vertical. / Regarding different clinical applications for bone grafts in alveolar reconstructions and difficulties on achieving vertical osseous increase the present study performed a comparative histological evaluation of demineralized freeze-dried bone allograft (DFDBA), of fresh frozen bone allograft (FFBA), autogenous graft (AU) and blood clot (CO) on vertical guided bone regeneration (GBR) in rabbit calvarium. Nine rabbits were used, with one as the primary bone graft donor and eight that were subjected to a model of GBR, whereby 32 titanium cylinders were fixed to the calvaria and randomly filled with DFDBA, FFBA, AU, or CO. The animals were sacrificed 13 weeks later, and the content of the cylinders was subjected to hitomorphological and histomorphometric analysis to quantify the total area of neoformed tissue (AT), the new bone tissue (NB) and residual graft particles (RG). The results showed that mean values for AT were significant to DFDBA and FFBA and followed the relation DFDBA = FFBA > AU > CO. Considering new bone formation DFDBA and FFBA showed better results than the AU and CO. The amount of residual bone particles was larger in the DFDBA and followed the relation FFBA > DFDBA = AU = CO (pvalues < 5%). All interventions showed greater new tissue formation nearby the receptor site. It was possible to conclude that allografts DFDBA and FFBA can be considered good strategies for new bone formation in vertical increasing bone.
454

Transplante renal em crianças com peso inferior a 15 kg : acesso cirúrgico extraperitoneal: experiência em 62 transplantes

Vitola, Santo Pascual January 2011 (has links)
Crianças pequenas representam um grupo desafiador no transplante renal. O estudo analisa os resultados, do ponto de vista cirúrgico, do transplante renal em crianças com peso inferior a 15 kg utilizando o acesso cirúrgico extraperitoneal. Métodos: Foram revisados retrospectivamente os prontuários de 62 crianças com peso inferior a 15 kg submetidas a transplante renal entre 1998 e 2010, utilizando o acesso extraperitoneal e anastomose dos vasos renais dos doadores com a aorta ou artéria ilíaca comum e com a veia cava inferior ou ilíaca comum dos receptores. O ureter foi anastomosado à bexiga pela técnica extravesical de Lich- Grégoir. Resultados: Dos 62 transplantes, 32 enxertos (51,6%) eram provenientes de doadores vivos e 30 (48,4%) de doadores falecidos, sendo 28 deles pediátricos. A média de idade no transplante foi de 3,7 ± 2,2 anos (1 a 12), e o peso médio, de 12,3 ± 2,1 kg (5,6 a 14,9), sendo que 10 tinham peso inferior a 10 kg. Em 10 crianças (16,1%) o transplante foi preemptivo e em 5 (8,1%) havia trombose do sistema venoso prévio ao transplante. Em 1 e 5 anos, a sobrevida do paciente foi de 93,2% e 84,2% e a sobrevida do enxerto de 85,2% e 72,7%, respectivamente, sem diferença entre doadores vivos e falecidos. A função do enxerto com doador vivo foi melhor em 1 e 3 meses, mas a partir do 6o mês foi similar. Houve 6 complicações vasculares, sendo 4 tromboses vasculares, 1 laceração e 1 estenose de artéria renal e 2 coleções líquidas. Houve 17 perdas de enxerto, 6 por morte, sendo 5 com enxerto funcionante, 5 por complicações cirúrgicas, 3 por rejeição crônica e 3 por recorrência da doença de base. Conclusão: O acesso extraperitoneal é uma técnica válida no transplante renal de crianças com peso inferior a 15 kg, assegurando boa sobrevida do paciente e do enxerto e aceitável taxa de complicações, independentemente do tipo de doador, se vivo ou falecido, ou do tamanho do enxerto, se de adulto ou de criança. / Small children are a challenging group for kidney transplantation. This study analyzes the results of kidney transplantation in children weighing less than 15 kg using the extraperitoneal surgical access. Methods: A retrospective review of the records of 62 children weighting less than 15 kg was done. The kidney transplantation were performed between 1998 and 2010 using the extraperitoneal access and anastomosis of the renal vessels of donors to the aorta or common iliac artery and to the inferior vena cava or common iliac vein of the recipients. The ureter was anastomosed to the bladder using the Lich-Grégoir extravesical technique. Results: Thirty-two (51.6%) grafts of the 62 transplants were from living donors and 30 (48.4%) from deceased donors, 28 of them pediatric. The mean age at transplantion was 3.7 ± 2.2 years (1 to 12), and the mean weight, 12.3 ± 2.1 kg (5.6 to 14.9), and 10 of them weighed less than 10 kg. In 10 children (16.1%) the transplant was preemptive. Five 5 (8.1%) children presented previous thrombosis of the venous system. At 1 and 5 years, patient survival was 93.2% and 84.2% and graft survival was 85.2% and 72.7%, respectively, and there was no difference between living and deceased donors. The graft function of the living donor was better at 1 and 3 months, but was similar from the 6th month onward. There were 6 vascular complications (4 of them vascular thromboses, 1 laceration and 1 renal artery stenosis) and 2 perirenal collections. Seventeen grafts were lost, 6 due to death, 5 with a functioning graft, 5 due to surgical complications, 3 due to chronic rejection and 3 due to recurrence of the original disease. Conclusion: The extraperitoneal access is a valid kidney transplantantion technique in children weighing less than 15 kg, ensuring good patient and graft survival, and an acceptable rate of complications, independent of source of donor, living or deceased, or size of graft, whether from an adult or from a child.
455

Análise da neoformação óssea em transplantes de osso autólogo, osso bovino mineral e tricálcio fosfato com e sem o emprego de células-tronco mesenquimais humanas no reparo de falhas ósseas alveolares por meio de histomorfometria e imagens / Analysis of bone formation of autogenous bone transfer, bovine bone mineral and tricalcium phosphate with and without mesenchymal stem cells in the repair of alveolar osseous defect using histomorphometry and radiological imaging

Cassio Eduardo Adami Raposo do Amaral 19 December 2012 (has links)
INTRODUÇÃO: O método padrão de reparo de falhas ósseas é o transplante do osso autólogo. No entanto, novas técnicas de bioengenharia de tecido ósseo poderão substituir o método padrão. A construção de uma técnica em bioengenharia de tecido ósseo é feita pela associação entre fatores ou células indutoras de osso e biomateriais carreadores. O objetivo do presente trabalho foi mensurar a neoformação óssea em falha óssea alveolar de modelo animal após o reparo com fontes diferentes de bioengenharia de tecido ósseo e compará-las com o reparo com o osso autólogo transplantado da região craniana. MÉTODOS: Foi criada uma falha óssea na região alveolar de 28 ratos Wistar medindo 5 mm de diâmetro. Quatro modalidades de reparo foram comparadas ao método padrão: No grupo 1 (método padrão), as falhas ósseas foram reparadas com o transplante de osso autólogo da região parietal da calvária; nos grupos 2 e 3, as falhas ósseas foram reparadas com o biomaterial carreador osso bovino mineral sem e com o emprego de células-tronco mesenquimais humanas indiferenciadas, respectivamente; nos grupos 4 e 5, as falhas ósseas foram reparadas com o biomaterial carreador -tricálcio fosfato sem e com o emprego de células-tronco mesenquimais humanas indiferenciadas, respectivamente. A neoformação óssea na falha alveolar foi aferida por meio de imagens de tomografia computadorizada e avaliação histomorfométrica após 8 semanas da cirurgia. A neoformação óssea obtida por meio da avaliação histomorfométrica possibilitou a comparação dos grupos 2, 3, 4 e 5 com o grupo 1. Foi criado um sistema de pontos para determinar a distribuição do osso na falha óssea alveolar por meio das imagens de tomografia computadorizada em cinco animais por grupo, sendo 1 ponto para ossificação parcial, 2 pontos para ossificação total e heterogênea e 3 pontos para ossificação total e homogênea. O índice de significância estatístico p<0,05 foi determinado pelo teste não paramétrico de Mann-Whitney. RESULTADOS: Na avaliação histomorfométrica, o grupo 1 apresentou 60,27% ± 16,13% de osso na falha (n=7). Os grupos 2 e 3 apresentaram respectivamente, 23,02% ± 8,6% (n=3) Resumo (p=0,01) e 38,35% ± 19,59% (n=5) (p=0,06) de osso na falha. Os grupos 4 e 5 apresentaram respectivamente, 51,48% ± 11,7% (n=3) (p=0,30) e 61,8% ± 2,14% (n=6) (p=0,88) de osso na falha. Na avaliação radiológica, os animais dos grupos 1, 2, 3, 4 e 5 apresentaram média de pontos respectivamente igual a 2; 1,4; 1,5; 1,6, 1,8. CONCLUSÕES: O grupo de animais cujas falhas ósseas alveolares foram reparadas com -tricálcio fosfato e células-tronco mesenquimais apresentou a neoformação óssea mais semelhante a do grupo de animais cujas falhas ósseas foram reparadas com osso autólogo / INTRODUCTION: The current criterion standard to repair bone defects is an autogenous bone transfer. However, bone engineering strategies may become the first choice in the future. Bone bioengineering strategies are created through the association of inductive factors, stem cells and biomaterial matrices. The objective of this study was to measure the bone formation in an alveolar osseous defect animal model using different bone tissue engineering strategies and to compare them with the autogenous bone transfer. METHODS: Alveolar circular bone defects measuring 5 mm of diameter were created in 28 Wistar rats. Four alternative modalities were compared to the traditional modality of autogenous bone transfer: In group 1 (traditional modality), defects were repaired with autogenous bone graft from the calvarial region; in groups 2 and 3, defects were repaired using bovine bone mineral free of cells and loaded with undifferentiated mesenchymal stem cells, respectively; in groups 4 and 5, defects were repaired with - tricalcium phosphate free of cells and loaded with mesenchymal stem cells, respectively. Groups 2, 3, 4 and 5 were compared with group 1. Bone formation was evaluated by computed tomography imaging, and by histomorphometry at 8 weeks after surgery. Radiologically, a score system was developed to determine the bone distribution measured by computed tomography imaging in five animals of each group. Statistical significance was determined as p<0.05 by the non-parametric statistical hypothesis test called the Mann-Whitney test. RESULTS: Histomorphometrically, group 1 showed 60.27% ± 16.13% of bone in the defect (n=7). Groups 2 and 3 showed respectively, 23.02% ± 8.6% (n=3) (p=0.01) and 38.35% ± 19.59% (n=5) (p=0.06) of bone in the defect. Groups 4 and 5 showed respectively, 51.48% ± 11.7% (n=3) (p=0.30) and 61.80% ± 2.14% (n=6) (p=0.88) of bone in the defect. Radiologically, groups 1, 2, 3, 4 and 5 scored on average 2, 1.4, 1.5, 1.6, 1.8, respectively. CONCLUSION: The group of animals whose alveolar osseous defects Summary were repaired with -tricalcium phosphate and mesenchymal stem cells showed the most similar bone formation to the group whose alveolar osseous defects were repaired with autogenous bone
456

Leptina: um modulador central das respostas imunes. / Leptin: a central modulator of imune responses.

Pedro Manoel Mendes de Moraes Vieira 07 October 2011 (has links)
A leptina é um mediador tanto de respostas neuroendócrinas como imunes, e tem sido associada a diversas autoimunidades. O nosso objetivo foi estudar a importância da leptina na modulação da resposta imunológica no transplante experimental, com ênfase em seu papel na plasticidade de linfócitos T e de células dendríticas (DC). Observamos que os animais deficientes em leptina têm uma sobrevida aumentada do enxerto de pele e uma menor frequência de células Th1 e maior T reguladoras (Treg), Th2 e Th17. Ademais, células T CD4+ naive diferenciam-se mais eficientemente em células Treg e Th17 tanto com DC como sem DC, na ausência de leptina. Nossos dados indicam que BMDC, imaturas e maduras, é comprometida na ausência de leptina, induzindo menor proliferação de linfócitos CD4+ e maior geração/expansão de células Treg, Th17 e Th2. Assim, a ausência de leptina resultou num predomínio de células Treg um padrão Th2 que, em conjunto com o perfil tolerogênico das DC, poderiam ser um dos mecanismos responsáveis pelo aumento da sobrevida do enxerto alogenêico de pele. / Leptin is a mediator of both neuroendocrine and immune responses, and has been associated with several autoimmune diseases. Our objective was to study the importance of leptin in modulating the immune response in experimental transplantation, with emphasis on its role in the plasticity of T lymphocytes and dendritic cells (DC). We observed that animals leptin deficient had an increased skin graft survival and lower frequency of Th1 and increased regulatory (Treg), Th2 and Th17 T cells. Furthermore, naive CD4+ T cells differentiate more efficiently in Treg and Th17 cells, with DC and without DC, in the absence of leptin. Our data indicate that BMDC, mature and immature, is compromised in the absence of leptin, leading to less proliferation of CD4+ and increased generation / expansion of Treg cells, Th2 and Th17. Thus, the lack of leptin resulted in a predominance of Th2 and Treg T cells, which together with the profile of tolerogenic DC could be one of the mechanisms responsible for increased survival of allograft skin.
457

Immunomodulation through the anti-inflammatory cholinergic pathway: impact on innate and acquired immunity in transplantation

Sadis, Claude 18 November 2015 (has links)
Up to now, solid organ transplantation remains the ultimate life-saving treatment for end-stage organ failure. However, transplantation could be complicated by allograft rejection wherein inflammation plays a pivotal role. In this process, inflammation secondary to ischemia/reperfusion and cell necrosis plays the role of adjuvant and enhances the antigen-specific adaptive response ultimately leading to allograft rejection. Therefore, anti-inflammatory strategies have to be developed to dampen inflammation and secondary alloreactivity. Recently, neuroimmune pathways and particularly the cholinergic anti-inflammatory pathway have been described to modulate inflammation in several experimental models as sepsis. The Vagus Nerve, the α7 nicotinic receptor (α7nAChR) and its agonists are specific targets to regulate the inflammatory response in several pathologies.The aim of this work is to investigate the potential protective effect of the cholinergic pathway in solid organ transplantation. In a model of renal ischemia/reperfusion injury induced by bilateral clamping of renal arteries, nicotine protects from renal dysfunction and tubular damages. This protection is associated to a reduction of inflammatory cytokines and neutrophils and is α7nAChR dependent. In a second part, we test the effect of the α7nACh receptor in a model of minor antigen mismatched skin allograft. Mice deficient for the α7nAChR reject earlier the skin allograft compared to α7nAChR +/+ mice and this is associated to higher Th1 and Th17 T cell responses. α7nAChR expressed on T cells is involved in skin allograft rejection as attested by adoptive transfer experiments in Rag H/H mice with either α7nAChR +/+ or α7nAChR H/H alloreactive T cells. The cholinergic pathway by itself or boosted by nicotinic agonists is able to modulate innate as well as acquired immune components involved in allograft rejection. Other agonists or devices used to stimulate the cholinergic pathway are actually developed in order to be more specific and to reduce toxicity. Our results are particularly relevant in human medicine as grafted organs lose their Vagus Nerve endings and their cholinergic regulatory innervation. / Doctorat en Sciences médicales (Médecine) / info:eu-repo/semantics/nonPublished
458

EPIGREN : une cohorte pharmaco-clinique en transplantation rénale – Objectifs, méthodes, caractéristiques des patients greffés rénaux et de leur qualité de vie / EPIGREN : a pharmaco-clinical cohort study in kidney transplantation – Objectives, methods, characteristics of kidney transplant recipients and of their quality of life

Fruit, Dorothée 18 December 2014 (has links)
Parmi toutes les études/cohortes existantes en transplantation rénale, peu d’entre elles étudient l’impact des paramètres pharmacologiques. L’utilisation d’un auto-questionnaire, en complément du dossier médical, a été validée pour le recueil de ces données. La comparaison du dossier médical et des auto-questionnaires pour la déclaration des événements indésirables a permis de mettre en évidence des différences. Les infections étaient les événements indésirables les plus déclarés par les médecins alors que les patients n’en déclaraient que très peu. L’observance, évaluée par l’auto-questionnaire, diminuait entre la 1ère et la 3ème année post-greffe, tout comme la sensation d’euphorie et de renaissance. En effet, le score de qualité de vie (QdV) de la dimension « Santé mentale » du ReTransQol diminuait entre ces deux périodes. En revanche, la peur de la perte du greffon du patient augmentait comme démontrée par la diminution du score de QdV de la dimension « Peur de la perte du greffon ». La QdV, évaluée par des questionnaires génériques ou spécifiques aux greffés rénaux, est aussi un paramètre important à prendre en compte dans le suivi des patients. Les propriétés psychométriques de la 2nde version du ReTransQol, ainsi que sa reproductibilité et sa sensibilité aux changements ont été validées dès le 3ème mois post-transplantation rénale. L’étude de pharmaco-économie Ephegren, suite de la cohorte Epigren, va notamment étudier les rapports coût-efficacité et coût-utilité des stratégies immunosuppressives et anti-cytomégalovirus. Ainsi, des recommandations pourront être proposées afin d’homogénéiser les pratiques et diminuer les coûts de prise en charge des greffés rénaux. / Among all existing studies/cohorts in kidney transplantation, only a few study the impact of the pharmacological parameters. In addition to the clinical file, the use of a self-administered questionnaire has been validated to collect these data. Comparison between clinical file and self-administered questionnaire concerning the reporting of adverse events highlighted some differences. Infections were the most reported adverse events by the physicians while the patients declared only a few. Adherence evaluated with the self-administered questionnaire decreased between the first and third post-transplantation year and so did the feeling of euphoria and revival. The « Mental health » dimension of the quality of life (QOL) ReTransQol score decreased over this period. However patients’ fear of losing the graft increased as shown by the decrease of the « Fear of losing the graft » dimension of the QOL score. QOL, evaluated by generic and kidney-transplanted-specific questionnaires is also an important parameter that must be considered in patient follow-up. Psychometric properties of the second version of the ReTransQol, as well as its reproducibility and its sensitivity to changes have been validated as early as the 3rd post-kidney-transplantation month. The pharmacoeconomic study Ephegren, development of Epigren cohort, will study the cost-effectiveness and cost-utility ratio of immunosuppressive and anti-cytomegalovirus strategies. Guidelines will then be proposed to standardise the treatments and decrease the management costs of kidney-transplant recipients.
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Etude des relations pharmacodynamiques, pharmacogénétiques et pharmacocinétiques des immunosuppresseurs anticalcineurines chez les transplantés hépatiques / Study of Pharmacodynamic, Pharmacogenetic and Pharmacokinetic relationships of anticalcineurin drugs

Noceti penza, Ofelia 01 July 2015 (has links)
Les inhibiteurs de la calcineurine (ICN) sont les immunosuppresseurs les plus employés en transplantation d’organe, malgré leur toxicité et leur efficacité imparfaite. Leurs effets présentent une large variabilité intra-et inter-individuelle, qui n’est pas expliquée par les différences de doses, de concentrations ou d’aires sous la courbe des concentrations en fonction du temps, ce qui limite les bénéfices du suivi thérapeutique pharmacologique et montre que d’autres facteurs contribuent à la variabilité de la réponse. Aucun biomarqueur unique actuellement disponible ne présente tous les prérequis idéaux, c'est -à-dire est à la fois non -invasif, fiable, sensible, spécifique, reproductible et disponible rapidement. Afin d’identifier des biomarqueurs pharmacodynamiques très spécifiques de l’inhibition de la calcineurine et reflétant une part importante de la variabilité inter-individuelle, nos travaux avaient pour objectifs d’explorer la pharmacodynamie des ICN, la force et la variabilité du signal le long de l’axe calcineurine, ainsi que les étapes où les sources de variabilité PD interne (génétiques) ou externe sont les plus influentes. Nos principaux résultats dans les PBMC de volontaires sains ex -vivo montrent que : l’inhibition de NFAT1 dans les noyaux de PBMC et celles de l’expression d’IL -2 et CD25 dans différentes sous -populations de lymphocytes T suivent des modèles I/Imax ; plusieurs polymorphismes dans les gènes impliqués dans la PD des ICN contribuent à la variabilité inter-individuelle de ces biomarqueurs. Chez des patients inscrits en liste d’attente de transplantation hépatique, nous avons pu : mesurer les biomarqueurs PD des ICN avant et après stimulation ex-vivo; montrer des relations PG/PK ainsi que PD/PD au sein de l’axe étudié. Chez des patients transplantés hépatique, ceux sous CsA avaient une plus grande variabilité inter-individuelle PD que ceux sous TAC, ainsi que différents types de régulations au sein de l’axe. En résumé, l’expression d’IL -2 et CD25 dans les lymphocytes T CD8+ ainsi que de CD25 dans les cellules T CD4+ pourraient être des biomarqueurs fiables de l’activité des ICN, qui intègrent la plus grande part de la variabilité inter-individuelle. De plus, des cas cliniques suggèrent que l’expression de NFAT1 dans les noyaux des PBMC pourrait aider à anticiper les épisodes d’infection, alors que la diminution des Treg et des niveaux élevés d’expression d’IL -2 dans les T CD8+ pourraient prédire la survenue du rejet cellulaire aigu. / Calcineurin inhibitors (CNI) are the immunosuppressants most employed in solid organ transplantation, despite their toxicity and suboptimal efficacy. Their effects show huge intra and inter-individual variability, not explained by differences in drug doses, concentrations or areas under the concentration -time curve, limiting the benefits of therapeutic drug monitoring and pointing that other factors contribute to response variability. No single biomarker currently available meets all the ideal requirements, i.e. non-invasiveness, reliability, sensitivity, specificity, reproducibility, and short turnaround time. To search for suitable PD biomarkers, i.e., with high specificity for calcineurin inhibition and most affected by inter-individual variability ,our works aimed at exploring the pharmacodynamics(PD) of CNI, the strength and variability of signal translation along the calcineurin pathway, as well as the steps where sources of internal (genetic) or external variability are the most influential .Our main results in healthy volunteers’ PBMC ex vivo showed : that the inhibition of NFAT1 in PBMC nuclei and of IL-2 and CD25 expression in different subsets of T lymphocytes followed I/Imax models; that IL-2 and CD25 responses to NFAT inhibition fitted and allosteric sigmoid model; and that several polymorphisms in genes involved in CNI PD participated in the inter-individual variability of these biomarkers. In patients on the waiting list of liver transplantation we were able: to measure CNI PD biomarkers before as well as after ex-vivo stimulation; to report PG/PD relationships, as well as PD/PD interactions within the pathway. In liver transplant recipients, those on cyclosporine showed more inter -individual PD variability than those on tacrolimus and different regulations within the pathway. In summary, IL-2 and CD25 in CD8+ T cells and CD25 in CD4+ T cells may be reliable biomarkers of CNI activity, with the largest inter-individual variability. Moreover , clinical cases suggest that NFAT1 levels in PBMC nuclei might help to anticipate infection episodes, while Tregs diminution and high levels of IL-2 expression in CD8+ T cells might predict acute cellular rejection.
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Etudes préliminaires à la transplantation utérine / Preliminary studies in uterus transplantation

Gauthier, Tristan 08 July 2015 (has links)
Malgré les progrès réalisés en procréation médicalement assistée, les patientes ayant une infertilité utérine (IU) ne peuvent à ce jour mener une grossesse, contrairement aux patientes présentant une infertilité d’origine ovarienne ou tubaire. La transplantation utérine (TU) pourrait être une alternative à l’adoption et à la gestation pour autrui (GPA). Objectifs : Réalisation d’études expérimentales, translationnelles et cliniques.Méthodologie : Au cours de cette thèse, des travaux expérimentaux chez la brebis ont compris l’évaluation de l’IRM pelvienne, la réalisation d’allo-transplantation utérine, l’étude d’un modèle d’immunosuppression et l’évaluation originale de la tolérance à l’ischémie froide de l’utérus utilisant la membrane chorio-allantoïdienne d’embryon de poulet (CAM). Les études translationnelles et cliniques ont compris l’évaluation du prélèvement utérin (PU) au sein d’un prélèvement multi-organe (PMO) avec analyse de la tolérance à l’ischémie froide de l’utérus humain, l’évaluation de l’expression HLA par immunohistochimie du tissu utérin et l’évaluation de l’intérêt vis-à-vis de la TU.Résultats : L’IRM semble être l’examen de choix pour l’évaluation du greffon utérin. L’allo-transplantation utérine chez la brebis est complexe notamment en raison de la difficulté d’obtenir une immunosuppression optimale. L’administration de ciclosporine à travers une gastrostomie optimise l’exposition au traitement mais n’est pas envisageable à moyen terme. La greffe de tissu utérin sur CAM a révélé la capacité de l’endomètre à proliférer après 24 heures d’ischémie froide suggérant une tolérance à l’ischémie supérieure à celle du myomètre. La réalisation d’un PU au sein d’un PMO semble reproductible. L’exposition des tissus utérins à 24 heures d’ischémie froide n’a pas révélé de modifications histologiques majeures ni de majoration du signal apoptotique par TUNEL ou Caspase 3 clivée. L’expression forte HLA I et II par l’endomètre suggère l’utilisation, en cas de TU, d’un protocole d’immunosuppression optimal et d’un appariement HLA. Enfin, la population de patientes ayant une IU, peu connue jusque-là, est majoritairement représentée par les femmes atteintes du syndrome MRKH. L’intérêt pour la TU semble réel, l’adoption voire la GPA ne semblant satisfaire ces patientes. Perspectives: Nous prévoyons d’évaluer la TU à partir de donneuses en état de mort encéphalique dans le cadre d’un PHRC national. Par ailleurs, nous continuons un entrainement chirurgical chez l’animal avec l’étude de la tolérance à l’ischémie reperfusion de l’utérus de brebis selon une période courte ou prolongée d’ischémie froide. / In case of uterine infertility, uterus transplantation could be an alternative to adoption or surrogacy. We performed different experimental, translationnal and clinical studies in the field of uterus transplantation. We assessed surgery of uterus retrieval, resistance of the uterus to cold ischemia, the HLA expression from the uterus and the demand from patients with uterine infertility for uterus transplantation.

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