Malignancy within the pancreatic head can arise from pancreatic duct, distal bile duct, ampulla or duodenum. Since September 2000, surgery for all pancreatic head malignancy (PHM) has been centralised into regional pancreatic centres where assessment of preoperative imaging and subsequent surgery is undertaken. As part of this guidance, surgery must be performed within 62-days of referral. This project will assess four aspects of the pre-operative pathway in PHM: 1) Potential variation in outcome of patients referred from different sites within a Cancer Network 2) Potential variation in outcome associated with different intervals to surgery within the 62 day guideline 3) The ability of interpretation of heterogeneous pre-operative CT scans from different hospitals to determine the resectability of PHM 4) The ability of CT scan to distinguish the different tumour types of PHM Images of a consecutive series of patients were re-reported and compared with final pathology reports. Good agreement was noted in determining the tumour origin of PHM (observed agreement = 0.758, Kappa= 0.6 (0.51-0.68)). In the assessment surgical outcomes, geographical isolation from the regional centre was not associated with delay to surgery. Variation in outcome between referral centres was however noted but this was not associated with travel distance. Although little association was noted between delay to surgery and outcome overall, a paradoxical improvement in survival was noted however for the small group of patients with ampullary tumours who waited longer than the median interval to surgery.

The presence of inflammation in the progression of fatty liver disease induced by fasting was determined in mink. Tumour necrosis factor alpha (TNF-?), and monocyte chemoattractant protein 1 (MCP-1) liver mRNA levels were quantified by real-time PCR. Mink fasted for 5 and 7 days had significantly higher levels of TNF-? and MCP-1 liver mRNA, compared to mink fasted for 0, 1, and 3 days. Mink fasted for 7 days, but re-fed for 28 days had the lowest mRNA levels of both TNF-?, and MCP-1 demonstrating the liver’s ability to restore homeostasis post-fasting. TNF-? mRNA levels were correlated with MCP-1 liver mRNA and liver fat percent. To confirm the physical presence of inflammation, slides stained with haematoxylin and eosin were analyzed for bile ducts resulting in no significant differences. Results indicate that elevated MCP-1 and TNF-? expression are associated with fasting induced fatty liver in mink.

Cholangiocarcinoma (CCA), or cancer of the bile ducts, is extremely prevalent in people from Laos and Thailand whose staple diet is uncooked fish which harbour the liver fluke, Opisthorchis viverrini. There is no stronger link between a parasite and cancer than that between O. viverrini and CCA. Indeed WHO data suggests that one in six infected people contract liver cancer derived from the fluke. In vitro and in vivo studies have indicated that the fluke’s excretory/secretory (ES) proteins are mitogenic and likely make significant contributions to the initiation of CCA. To identify these carcinogenic components I undertook two distinct yet related approaches - (1) traditional protein purification methods to separate ES products, specifically targeting mitogenic proteins, and, (2) bioinformatic screening of 5,000 expressed sequences tags (ESTs) and ES proteins characterized by shotgun proteomic approaches, searching for homologues of molecules that are associated with human cancers. The protein purification approach utilized a cell proliferation assay that I developed for measuring cell replication rates in NIH-3T3 fibroblast and human CCA (KKU-100) cell lines stimulated with ES products. ES products were separated by a combination of ion exchange, hydrophobic interaction, size exclusion and a final ion exchange polishing chromatography steps. ES products and chromatographically separated ES proteins were added to cultured cells to observe mitogenic activity. A four-step purification process resulted in the isolation of 23 and 31 kDa proteins that stimulated cell proliferation at just picomolar quantities. These proteins account for a very small proportion of the total protein biomass (6 ppm and 39 ppm respectively) secreted by the parasite. Their identities are currently being explored using alternate proteomic approaches. Some growth factors bind to heparin, so an alternative purification process was developed using a heparin affinity column to purify ES mitogens. In combination with ion exchange chromatography a 20 kDa heparin-binding protein was identified using tandem mass spectrometry as a member of the sperm-coating protein 65 (SCP)-like extracellular proteins, also called SCP/Tpx-1/Ag5/PR-1/Sc766 (SCP/TAPS; Pfam accession number no. PF00188). The O. viverrini heparin-binding SCP/TAPs protein shared similarity with secreted proteins from other parasitic helminths including the hookworm activation-associated protein family, some of which are known to bind to host cells. In silico screening of the O. viverrini ESTs and ES peptides generated by mass spectrometry for proteins associated with cell proliferation and cancer revealed numerous secreted proteins of interest. One of these proteins shared identity with granulin, a vertebrate growth factor. The cDNA corresponding to this protein was termed Ov-grn-1. The predicted molecular characteristics of Ov-GRN-1 (isoelectric point and molecular weight) corresponded with the biochemical properties of the semi-purified mitogen that was chromatographically purified from ES products. Recombinant Ov-GRN-1 was expressed in E. coli in inclusion bodies and the purified denatured protein was refolded to produce a soluble protein. Refolded Ov-GRN-1 stimulated proliferation of NIH-3T3 fibroblasts at nanomolar concentrations and induced shape changes in affected cells. Antibodies raised to recombinant Ov-GRN-1 inhibited the ability of O. viverrini ES products to induce proliferation of fibroblasts and the KKU-100 CCA cell line in vitro, indicating that Ov-GRN-1 is the major growth factor present in O. viverrini ES products. This is the first report of a secreted growth factor from a parasitic worm that induces proliferation of host cells, and supports a role for this fluke protein in establishment of a tumourigenic environment that may ultimately manifest as CCA.

Cholangiocarcinoma (CCA), or cancer of the bile ducts, is extremely prevalent in people from Laos and Thailand whose staple diet is uncooked fish which harbour the liver fluke, Opisthorchis viverrini. There is no stronger link between a parasite and cancer than that between O. viverrini and CCA. Indeed WHO data suggests that one in six infected people contract liver cancer derived from the fluke. In vitro and in vivo studies have indicated that the fluke’s excretory/secretory (ES) proteins are mitogenic and likely make significant contributions to the initiation of CCA. To identify these carcinogenic components I undertook two distinct yet related approaches - (1) traditional protein purification methods to separate ES products, specifically targeting mitogenic proteins, and, (2) bioinformatic screening of 5,000 expressed sequences tags (ESTs) and ES proteins characterized by shotgun proteomic approaches, searching for homologues of molecules that are associated with human cancers. The protein purification approach utilized a cell proliferation assay that I developed for measuring cell replication rates in NIH-3T3 fibroblast and human CCA (KKU-100) cell lines stimulated with ES products. ES products were separated by a combination of ion exchange, hydrophobic interaction, size exclusion and a final ion exchange polishing chromatography steps. ES products and chromatographically separated ES proteins were added to cultured cells to observe mitogenic activity. A four-step purification process resulted in the isolation of 23 and 31 kDa proteins that stimulated cell proliferation at just picomolar quantities. These proteins account for a very small proportion of the total protein biomass (6 ppm and 39 ppm respectively) secreted by the parasite. Their identities are currently being explored using alternate proteomic approaches. Some growth factors bind to heparin, so an alternative purification process was developed using a heparin affinity column to purify ES mitogens. In combination with ion exchange chromatography a 20 kDa heparin-binding protein was identified using tandem mass spectrometry as a member of the sperm-coating protein 65 (SCP)-like extracellular proteins, also called SCP/Tpx-1/Ag5/PR-1/Sc766 (SCP/TAPS; Pfam accession number no. PF00188). The O. viverrini heparin-binding SCP/TAPs protein shared similarity with secreted proteins from other parasitic helminths including the hookworm activation-associated protein family, some of which are known to bind to host cells. In silico screening of the O. viverrini ESTs and ES peptides generated by mass spectrometry for proteins associated with cell proliferation and cancer revealed numerous secreted proteins of interest. One of these proteins shared identity with granulin, a vertebrate growth factor. The cDNA corresponding to this protein was termed Ov-grn-1. The predicted molecular characteristics of Ov-GRN-1 (isoelectric point and molecular weight) corresponded with the biochemical properties of the semi-purified mitogen that was chromatographically purified from ES products. Recombinant Ov-GRN-1 was expressed in E. coli in inclusion bodies and the purified denatured protein was refolded to produce a soluble protein. Refolded Ov-GRN-1 stimulated proliferation of NIH-3T3 fibroblasts at nanomolar concentrations and induced shape changes in affected cells. Antibodies raised to recombinant Ov-GRN-1 inhibited the ability of O. viverrini ES products to induce proliferation of fibroblasts and the KKU-100 CCA cell line in vitro, indicating that Ov-GRN-1 is the major growth factor present in O. viverrini ES products. This is the first report of a secreted growth factor from a parasitic worm that induces proliferation of host cells, and supports a role for this fluke protein in establishment of a tumourigenic environment that may ultimately manifest as CCA.

A exploração visual dos dutos biliares é de relevante interesse clínico, pois fornece informação relacionada com a Atresia Biliar (AB). A AB é uma doença cujas causas ainda permanecem desconhecidas e que eventualmente leva a um transplante de fígado ou, nos casos mais avançados da doença, leva a óbito do paciente. A única evidência física conhecida até agora da existencia de AB é a obstrução das vias biliares. No entanto, o estudo desta doença tem sido limitado pela incapacidade de analisar o duto biliar de pacientes em estágios precoces da doença e muito pouco se sabe sobre a estrutura interna do duto biliar. Nos últimos anos, a microscopia confocal, uma técnica que permite a obtenção de conjuntos de dados 3D de amostras biológicas, tem sido utilizada em experiências médicas para estudar a estrutura interna e anatômica dos dutos biliares. Neste trabalho, é objetivo apoiar o estudo dessas estruturas através da visualização volumétrica de imagens dos dutos biliares. É proposto um pipeline de fluxo de dados capaz de processar e "renderizar"conjuntos de dados de imagens confocais utilizando o VTK (do inglês The Visualization ToolKit). O pipeline foi construído em duas etapas principais e consecutivas. Uma primeira etapa tem o objetivo de remoção de ruído e realce das estruturas relevantes por meio de filtragem no domínio da freqüência e difusão anisotrópica. O conjunto de dados assim pré-processado é usado com técnicas diretas de visualização de volumes baseadas em funções de transferência para exibir as estruturas dos dutos biliares. Os resultados mostram que a visualização volumétrica em conjunto com um pré-processamento adequado das imagens confocais permite evidenciar as regiões de interesse nos dutos biliares e melhora detalhes que são dificilmente visualizados nos dados originais. / The visual exploration of bile ducts in the liver is of relevant clinical interest, as it provides information related to the Biliary Atresia, a disease of unknown origin, which eventually leads to a liver transplant or ultimately to death. The only physical known evidence of biliary atresia is the obstruction of the bile ducts. However, the study of this disease has been limited by the inability to observe the bile duct in patients at early stages of the disease. Moreover, very little is known about the internal structure of the bile duct. In recent years, confocal microscopy, a technique that allows to obtain 3D image datasets from biological samples, has been used in medical experiments for studying the anatomical internal structure of bile ducts. We are interested in supporting the study of these structures through volumetric visualization of bile ducts images. In this work, we propose a data flow pipeline capable of processing and rendering datasets of confocal images using The Visualization ToolKit - VTK. The pipeline was built as two consecutive stages. We propose a first stage for denoising and enhancing the relevant structures of sample based on filtering in the frequency domain and anisotropic diffusion. We use the dataset preprocessed in this way for applying a direct volume rendering technique in a second stage based on transfer functions to visualize the bile duct structures. Our results have shown that volumetric visualization together with an adequate pre-processing of the confocal images allow experts to visualize the regions of interest in the bile ducts, improving details that are hardly visualized in the original data.

A exploração visual dos dutos biliares é de relevante interesse clínico, pois fornece informação relacionada com a Atresia Biliar (AB). A AB é uma doença cujas causas ainda permanecem desconhecidas e que eventualmente leva a um transplante de fígado ou, nos casos mais avançados da doença, leva a óbito do paciente. A única evidência física conhecida até agora da existencia de AB é a obstrução das vias biliares. No entanto, o estudo desta doença tem sido limitado pela incapacidade de analisar o duto biliar de pacientes em estágios precoces da doença e muito pouco se sabe sobre a estrutura interna do duto biliar. Nos últimos anos, a microscopia confocal, uma técnica que permite a obtenção de conjuntos de dados 3D de amostras biológicas, tem sido utilizada em experiências médicas para estudar a estrutura interna e anatômica dos dutos biliares. Neste trabalho, é objetivo apoiar o estudo dessas estruturas através da visualização volumétrica de imagens dos dutos biliares. É proposto um pipeline de fluxo de dados capaz de processar e "renderizar"conjuntos de dados de imagens confocais utilizando o VTK (do inglês The Visualization ToolKit). O pipeline foi construído em duas etapas principais e consecutivas. Uma primeira etapa tem o objetivo de remoção de ruído e realce das estruturas relevantes por meio de filtragem no domínio da freqüência e difusão anisotrópica. O conjunto de dados assim pré-processado é usado com técnicas diretas de visualização de volumes baseadas em funções de transferência para exibir as estruturas dos dutos biliares. Os resultados mostram que a visualização volumétrica em conjunto com um pré-processamento adequado das imagens confocais permite evidenciar as regiões de interesse nos dutos biliares e melhora detalhes que são dificilmente visualizados nos dados originais. / The visual exploration of bile ducts in the liver is of relevant clinical interest, as it provides information related to the Biliary Atresia, a disease of unknown origin, which eventually leads to a liver transplant or ultimately to death. The only physical known evidence of biliary atresia is the obstruction of the bile ducts. However, the study of this disease has been limited by the inability to observe the bile duct in patients at early stages of the disease. Moreover, very little is known about the internal structure of the bile duct. In recent years, confocal microscopy, a technique that allows to obtain 3D image datasets from biological samples, has been used in medical experiments for studying the anatomical internal structure of bile ducts. We are interested in supporting the study of these structures through volumetric visualization of bile ducts images. In this work, we propose a data flow pipeline capable of processing and rendering datasets of confocal images using The Visualization ToolKit - VTK. The pipeline was built as two consecutive stages. We propose a first stage for denoising and enhancing the relevant structures of sample based on filtering in the frequency domain and anisotropic diffusion. We use the dataset preprocessed in this way for applying a direct volume rendering technique in a second stage based on transfer functions to visualize the bile duct structures. Our results have shown that volumetric visualization together with an adequate pre-processing of the confocal images allow experts to visualize the regions of interest in the bile ducts, improving details that are hardly visualized in the original data.

A exploração visual dos dutos biliares é de relevante interesse clínico, pois fornece informação relacionada com a Atresia Biliar (AB). A AB é uma doença cujas causas ainda permanecem desconhecidas e que eventualmente leva a um transplante de fígado ou, nos casos mais avançados da doença, leva a óbito do paciente. A única evidência física conhecida até agora da existencia de AB é a obstrução das vias biliares. No entanto, o estudo desta doença tem sido limitado pela incapacidade de analisar o duto biliar de pacientes em estágios precoces da doença e muito pouco se sabe sobre a estrutura interna do duto biliar. Nos últimos anos, a microscopia confocal, uma técnica que permite a obtenção de conjuntos de dados 3D de amostras biológicas, tem sido utilizada em experiências médicas para estudar a estrutura interna e anatômica dos dutos biliares. Neste trabalho, é objetivo apoiar o estudo dessas estruturas através da visualização volumétrica de imagens dos dutos biliares. É proposto um pipeline de fluxo de dados capaz de processar e "renderizar"conjuntos de dados de imagens confocais utilizando o VTK (do inglês The Visualization ToolKit). O pipeline foi construído em duas etapas principais e consecutivas. Uma primeira etapa tem o objetivo de remoção de ruído e realce das estruturas relevantes por meio de filtragem no domínio da freqüência e difusão anisotrópica. O conjunto de dados assim pré-processado é usado com técnicas diretas de visualização de volumes baseadas em funções de transferência para exibir as estruturas dos dutos biliares. Os resultados mostram que a visualização volumétrica em conjunto com um pré-processamento adequado das imagens confocais permite evidenciar as regiões de interesse nos dutos biliares e melhora detalhes que são dificilmente visualizados nos dados originais. / The visual exploration of bile ducts in the liver is of relevant clinical interest, as it provides information related to the Biliary Atresia, a disease of unknown origin, which eventually leads to a liver transplant or ultimately to death. The only physical known evidence of biliary atresia is the obstruction of the bile ducts. However, the study of this disease has been limited by the inability to observe the bile duct in patients at early stages of the disease. Moreover, very little is known about the internal structure of the bile duct. In recent years, confocal microscopy, a technique that allows to obtain 3D image datasets from biological samples, has been used in medical experiments for studying the anatomical internal structure of bile ducts. We are interested in supporting the study of these structures through volumetric visualization of bile ducts images. In this work, we propose a data flow pipeline capable of processing and rendering datasets of confocal images using The Visualization ToolKit - VTK. The pipeline was built as two consecutive stages. We propose a first stage for denoising and enhancing the relevant structures of sample based on filtering in the frequency domain and anisotropic diffusion. We use the dataset preprocessed in this way for applying a direct volume rendering technique in a second stage based on transfer functions to visualize the bile duct structures. Our results have shown that volumetric visualization together with an adequate pre-processing of the confocal images allow experts to visualize the regions of interest in the bile ducts, improving details that are hardly visualized in the original data.

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No. of bitstreams: 1 paulohenriquediasdecarvalho.pdf: 3125617 bytes, checksum: 3e951b5c5e73d3862e1ed9b6e9e28451 (MD5) Previous issue date: 2013-07-26 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico / FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais / A descoberta de protótipos naturais associada às metodologias de isolamento e identificação química de constituintes a partir de novas fontes botânicas, bem como da avaliação das atividades farmacológicas e toxicológicas dessas moléculas demonstram grandes perspectivas para o desenvolvimento racional de novos fármacos. Tendo em vista a alta incidência de doenças do fígado, no Brasil e no mundo, e que existem poucos medicamentos eficazes e capazes de reverter ou reduzir a progressão destas, o isolamento e a identificação de substâncias com potencial hepatoprotetor é, hoje, uma área promissora na busca de novas substâncias bioativas. Tradicionalmente, as raízes de Glycyrrhiza sp., conhecidas como licorice, são usadas na medicina alternativa com inúmeras finalidades, dentre elas hepatoprotetora. Entretanto, até o momento, não existem relatos desta atividade vinculada à licochalcona A, uma das substâncias majoritárias nas raízes de Glycyrrhiza inflata. No presente trabalho avaliaram-se as atividades da licochalcona A em ensaios de viabilidade celular das linhagens de fibroblásto (NIH/3T3) e carcinoma hepatocelular humano (HepG-2), adesão celular de HepG-2 e em modelo de lesão hepática induzida por ligação do ducto biliar (BDL) em ratos Wistar. Além disso, desenvolveu-se uma metodologia para determinação da licochalcona A em CLAE-UV, utilizando coluna C18, fase móvel em gradiente de água acidificada (0,1% H3PO4) e metanol (50:50 – 20:80 v/v), fluxo de 1,1 mL/min e comprimento de onda para detecção em 372 nm. A licochalcona A isolada a partir do extrato seco das raízes de G. inflata foi identificada por RMN 1H e 13C. O isolamento apresentou-se satisfatório, bem como a metodologia proposta para quantificação desta substância por CLAE-UV, que apresentou excelente linearidade, precisão e exatidão. Nos experimentos in vitro, a licochalcona A não demonstrou redução significativa na viabilidade das células da linhagem HepG-2 (IC50 > 200 μM) e da NIH/3T3 (IC50 > 100 μM), bem como no experimento de adesão das células HepG-2 (IC50 > 200 μM) (p>0,05). Estes dados corroboram com aqueles encontrados no experimento in vivo, no qual a licochalcona A (50 mg/Kg) também não apresentou toxicidade ao fígado, já que os resultados encontrados não foram significativamente diferentes aos do grupo controle (p>0,05). Contudo, ela também não demonstrou capacidade de promover ou reduzir os danos hepáticos causado pelo BDL, no tempo de tratamento do estudo realizado (48 h). / The natural prototypes discovery associated with methods of chemical constituents isolation and identification from new botanical sources, as well as the evaluation of pharmacological and toxicological activities of these molecules show great prospects for the new drugs rational development. In view of the high incidence of liver disease in Brazil and the world, and there are few effective drugs and able to reverse or slow the progression of these disease, the substances isolation and identification with potential hepatoprotective today is a promising area in search for new bioactive substances. Traditionally, the roots of Glycyrrhiza sp., known as licorice, are used in alternative medicine with numerous purposes, among them hepatoprotective. However, to date, there are no reports of this activity linked to licochalcona A, one majority of the substances in the roots of Glycyrrhiza inflata. In the present study evaluated the activities of licochalcone A in cell viability assays of strains fibroblast (NIH/3T3) and human hepatocellular carcinoma (HepG-2), cell adhesion HepG-2 and model of liver injury induced by bile duct ligation (BDL) in Wistar rats. In addition, we developed a methodology for determining the licochalcone A quantitative HPLC-UV, using C18 column and a mobile phase gradient of acidified water (0.1% H3PO4) and methanol (50:50 - 20:80 v/v), flow rate of 1.1 mL/min and detection wavelength at 372 nm. The licochalcone A isolated from the dried extract of the roots of G. inflata was identified by 1H and 13C NMR. The isolation had to be satisfactory, as well as the proposed methodology for quantification of this substance by HPLC-UV, which showed excellent linearity, reproducibility and accuracy. In in vitro experiments, licochalcone A showed no significant reduction in the viability of the cell line HepG-2 (IC50 > 200 μM) and NIH/3T3 (IC50 > 100 μM), as well as in cell adhesion HepG-2 experiments (IC50 > 200 μM) (p> 0.05). These data corroborate those found in the in vivo experiment, in which the licochalcone A (50 mg/kg) also showed no toxicity to the liver, since the results were not significantly different to the control group (p>0.05). Nevertheless, it has not shown the ability to promote or reduce liver damage caused by BDL, at the treatment time of the study (48 h).

As células derivadas de fígado embrionário tanto de animais quanto de humanos tem sido cada vez mais estudas devido ao seu potencial antiinflamatório, imunomodulador e regenerativo, demonstrado as mesmas bipotencial de diferenciação em hepatócitos e colangiocitos. Na presente pesquisa utilizou-se células derivadas de fígados embrionários de ratos com 14,5 dias de gestação. As células apresentaram marcadores de células progenitoras hepáticas, bem como marcadores de células hepáticas e biliares diferenciadas confirmando, seu bipotencial. A terapia celular utilizando as células supracitadas, reduziu significativamente a progressão da fibrose hepática, diminuindo a inflamação e ainda estimulando a regeneração hepática de ratos submetidos à cirrose por ligadura do ducto biliar. As análises realizadas mediante avaliação quantitativa pela técnica de morfometria, demonstraram redução da deposição de fibras de colágeno, bem como menor proliferação de ductos biliares nos animais tratados. Os resultados foram ainda complementados por analise semiquantitativa, a qual avaliou a intensidade da necroinflamação dos tecidos hepáticos analisados, apontando menor escore de inflamação dos animais tratados. As células poderão ter efeito benéfico para o tratamento de doenças hepáticas crônicas, que estimulam a formação de fibrose. A cirrose é o estágio final comum à doenças hepáticas crônicas por causadas por fatores de diversas etiologias. Esta ocupa a decima quarta causa mundial de mortalidade em humanos, sendo que o único tratamento definitivo atualmente é transplante do órgão. Entretanto o número de transplantes está longe de suprir a demanda atual, visto que há um déficit de doadores do órgão. Terapias que possam oferecer uma alternativa de tratamento confiável, segura e acessível são bastante oportunas. Nossos resultados sugerem que as células utilizadas neste trabalho podem modular a fibrogênese, e consequentemente retardar o estabelecimento da cirrose em doenças hepáticas crônicas. / Studies on human and animal embryonic liver stem cells have been growing due to its anti-inflammatory, immunomodulatory and regenerative potential. These cells show also a bipotential do differentiate into hepatocytes and cholangiocytes. In the present study, it was used rodent embryonic liver with 14.5 of gestation. The cells presented hepatic progenitor, as well adult hepatic and biliary cells markers, confirming their bipotential. Previous studies with these cells in therapy decreased hepatic fibrosis progression in rat models submitted to cirrhosis by biliary duct ligation. Quantitative analysis was performed by morphometry showed decreased collagen fibers deposition and lower proliferation of biliary ducts in treated animals. Results were complemented with semiquantitative analysis with evaluation of necroinflammation of the analyzed hepatic tissues, in which a decreased inflammation score was observed. Cirrhosis is a common final stage for chronic hepatic diseases caused by different factors in several etiologies. It occupies the 14th world cause of mortality in human. However, the number of liver transplants is insufficient for current demand, caused by deficit in organs donors. Therapies that could offer an alternative for a reliable, safe and accessible treatment is opportune. Our results suggest that cells used in this study can modulate fibrogenesis and consequently delay the establishment of cirrhosis in chronic liver diseases.

Nous avons récemment démontré un bénéfice de l’implantation d’un drain biliaire interne (IBS-Internal Biliary Stent) afin de réduire les complications biliaires en transplantation hépatique. Le drain IBS en silicone est utilisé en pratique clinique, son utilisation nécessite une procédure d’ablation endoscopique, intervention qui n’est pas dénuée de complications. Afin d’éviter cela, et pour réduire les complications biliaires après transplantation hépatique, nous avons cherché à développer une prothèse biliaire interne résorbable (RIBS-Resorbable Internal Biliary Stent), fabriquée à partir d'un polymère dégradable radio-opaque. Pour être implantable, le RIBS doit répondre à un cahier des charges.Le premier objectif de ce travail était de synthétiser le matériau et le mettre en forme à partir d'un copolymère tribloc initialement sélectionné de PLA50-PEG-PLA50 avec un additif radio-opaque composé d’un copolymère de triiodobenzoate-poly(-caprolactone) (PCL-TIB). Le RIBS doit non seulement être toléré par l’organisme mais doit permettre de sécuriser l’anastomose biliaire et favoriser la régénération tissulaire biliaire pour ensuite être éliminée de l’organisme. Ce dispositif doit également répondre aux objectifs très strictes liés à l’implantation et au suivi en TH. Le second objectif était de caractériser le RIBS de PCL-TIB/PLA50-PEG-PLA50, en évaluant si les propriétés au cours de la dégradation in vitro et in vivo étaient conformes au cahier des charges. Une étude in vitro dans un environnement biliaire simulé et une étude in vivo chez le rat ont été réalisées. Nous avons observé les propriétés physico-chimiques, la visualisation radiologique, l'histologie et le comportement mécanique au cours de la dégradation. Enfin, le dernier objectif était d'évaluer l'implantabilité ex vivo dans les voies biliaires humaines, avec une étude du comportement mécanique des voies biliaires et des tests d'implantation sur des pièces anatomiques.Dans cette thèse, le comportement radiologique et mécanique du dispositif RIBS innovant a été évalué avec succès au cours la dégradation in vitro et in vivo, avec des propriétés qui répondaient aux exigences. Un prototype de RIBS a été implanté avec succès dans une pièce anatomique humaine. Ces travaux ont permis le développement d’un dispositif innovant, à savoir un IBS traçable et biodégradable utilisable pour réduire les complications biliaires en transplantation hépatique. / Benefit of implantation of an internal biliary stent (IBS) during liver transplantation to reduce biliary complications was recently demonstrated. Silicone IBS was used in practice, which require an endoscopic ablation procedure, a potentially morbid intervention for the patient. In order to avoid this, and to reduce biliary complications after liver transplantation we develop a resorbable internal biliary stent (RIBS), made from a degradable polymer visualizable by X-ray. To be usable and useful, RIBS must comply specifications, which are developed in this thesis.The first aim of the present work, was to synthetize a material based on a selected PLA50-PEG-PLA50 triblock copolymer with a triiodobenzoate-poly(-caprolactone) radiopaque copolymer (PCL-TIB) as additive and design a RIBS. It must be biocompatible, should secure the biliary anastomosis and enable biliary regeneration. This device will also have to meet the very strict objectives related to implementation and monitoring in liver transplantation. The second objective was to characterize the PCL-TIB/PLA50-PEG-PLA50 RIBS, by evaluating whether properties during in vitro and in vivo degradation complied the specifications. An in vitro study in a simulated biliary environment and an in vivo rats implantation study was realized. We observed physico-chemical properties, radiological visualization, histology, and mechanical behavior during degradation. The last aim was to evaluate ex vivo implantability in human bile ducts, with the study of the bile duct mechanical behavior, and implantation tests on anatomic specimens.In this thesis, radiological and mechanical behaviour of novel radiopaque and resorbable IBS was successfully evaluated during in vitro and in vivo degradation with properties that meet requirements. A RIBS prototype device was successfully implanted in human anatomic specimen. The results obtained will allow the development of a novel class of trackable and degradable IBS to reduce biliary complications after liver transplantation.