INTRODUÇÃO: Influenza é uma doença potencialmente grave após o transplante de células tronco hematopoiéticas (TCTH). A vacinação é a principal estratégia profilática, mas a resposta imune é menor do que em indivíduos saudáveis. Em geral os pacientes não respondem a vacinação nos primeiros seis meses após transplante, o que torna o período de maior vulnerabilidade. OBJETIVOS: Neste estudo avaliaram-se diferentes esquemas de vacinação contra influenza em TCTH alogênico relacionado, com imunização do doador e/ou do receptor no pré transplante. Determinou-se a resposta a vacina comparando-se as taxas de soroconversão entre os grupos de intervenção. Foram avaliados também os níveis de anticorpos considerados soroprotetores alcançados. MÉTODOS: Realizou-se ensaio clinico randomizado não cego, em população de candidatos ao TCTH e seus doadores do Hospital das Clínicas da Faculdade de Medicina da Universidade Federal de Minas Gerais/BH-MG e Hospital Amaral Carvalho/Jaú-SP. Quatro grupos de pares receptor-doador receberam diferentes esquemas de imunização de influenza no pré transplante: 1- sem vacinação, 2 - vacinação do doador; 3 - vacinação do receptor e 4 - vacinação de doador e receptor. Todos os pacientes receberam vacina a partir do 6º mês após transplante. Acompanhamento sorológico do par foi realizado no pré e no dia do transplante, e nos dias 30, 60, 100, 180 e após vacina apenas para os receptores. Títulos dos anticorpos sorotipo - específicos foram determinados pela reação de inibição de hemaglutinação. Níveis 1:40 foram considerados protetores e < 1:10 negativos. Soroconversão foi definida como aumento de quatro vezes ou mais dos títulos ou aumento de <1:10 para 1:40. RESULTADOS: De 08/2007 a 02/2010 131 pares receptor-doador foram incluídos e randomizados: 38 no grupo 1, 44 no grupo 2, 40 no grupo 3 e 9 no grupo 4. Não houve diferença estatística entre os grupos com relação às características clínicas. As taxas de soroproteção basal dos receptores foram de 18%, 32,8% e 63,3% para influenza A/H1N1, A/H3N2 e B, respectivamente. A condição sorológica pré transplante dos doadores foi semelhante. As taxas de soroconversão dos doadores foram de 30,1%, 41,5% e 30,9%, respectivamente para os A/H1N1, A/H3N2 e B. Nos receptores soroconversão até o dia 30 após transplante ocorreu em 16,3% dos pacientes para o A/H1N, 14,7% para A/H3N2 e 28,7%. As médias geométricas dos títulos de anticorpos neutralizantes foram calculadas para todos os subtipos virais ao longo do tempo. Para o A/H1N1 não houve diferença dos títulos até o D180 para nenhum dos grupos. Para o A/H3N2 houve diferença nos títulos no momento do transplante (p=0,019), com maiores títulos nos grupos 2 e 3 em relação ao grupo 1 e no dia 30 (p=0,018) com menores títulos para o grupo 4 que os demais. Para o subtipo B, as diferenças entre os grupos ocorreram no dia do transplante (p=0,020) e nos dias 30 (p= 0,018) e 60 (p=0,026) com menores títulos do grupo 4 em relação aos demais. As taxas de soroconversão após a vacina do dia 180 foram de 19,7% para o A/H1N1, 18% para o A/H3N2 e 8,2% para o B. Não houve diferença estatisticamente significante entre os grupos. CONCLUSÃO: A imunogenicidade da vacina de influenza em receptores de TCTH foi baixa. A estratégia de vacinação do doador e do receptor no pré transplante aumentou a média geométrica dos títulos protetores apenas para o subtipo A/H3N2 até o 30º pós transplante, em relação ao grupo sem vacinação / INTRODUCTION: Influenza is a potentially severe illness after hematopoietic stem cell transplantation (HSCT). Vaccination is the main prophylactic strategy, but the immune response is limited in the compromised host. Existing data support the recommendation of influenza vaccination after the 6th month of HSCT. OBJECTIVES: The study evaluated different schedules of influenza vaccination in HSCT. Recipient and/or their donors were randomized to receive influenza vaccine before transplant. The primary outcome was the comparison of serotype response between groups at baseline, 30 days and 6 months after transplantation. METHODS: A randomized, non-blind trial was conducted in patients undergoing HSCT and respective donors at Hospital das Clínicas, Universidade Federal de Minas Gerais /BH-MG and at Hospital Amaral Carvalho/Jaú-SP. Four groups of donor and recipient pairs received different influenza immunization at least 7 days before HSCT: group 1 no vaccination, group 2 donor received a single dose of influenza vaccine; group 3 recipients received a single dose of influenza vaccine and group 4 recipients and donor received influenza vaccine. Following transplantation, all study patients were immunized with influenza vaccine at 6 months. Donor serum samples were collected at baseline (pre transplantation) and in the day of transplantation. Recipients serum samples were taken at baseline, 30, 60, 100, 180 days after transplantation, and at least 2 weeks after 6-month vaccination. The hemagglutination inhibition assay (HIA) was performed to evaluate immune response. HI antibodies titers 1:40 were considered protective. Titers < 1:10 were considered negative. Antibody response (seroresponse) was defined as the appearance or 4-fold rise in HI antibody titers after vaccination. RESULTS: From August 2007 to February 2010 131 donor and recipient pairs were included in the study: 38 pairs in group 1, 44 in the group 2 , 40 in 3 group and 9 in group 4.There were no statistically difference between the 4 groups regarding to the clinical characteristics. At baseline 18% of recipients had protective antibody levels to A/H1N1, 32.8% to A/H3N2 and 63.3% to B. Donor serological condition was similar to recipients. Seroresponse occurred in 30,1% of donors to A/H1N1, 41,5% to A/H3N2 and 30,9% to B. Seroresponse until day 30 after transplant were detected in only 16,3% of the patients for the A/H1N, 14.7% for A/H3N2 and 28.7% for B. Comparisons of geometric mean antibody concentrations was performed at baseline and day of transplantation, and also at 30, 60, 100, 180 days after HSCT e after 6 months influenza vaccine. For the A/H1N1 there was no statistically difference between groups until 180 days after HSCT. For the A/H3N2 a significant increase in geometric mean titers in the day of transplantation (p=0,019) was observed in groups 2 and 3 in relation to group 1 and lower geometric mean titers (p=0,018) at day 30 for patients in group 4. For subtype B, the differences between groups occurred in the day of the transplantation (p=0,020) and at 30 (p= 0,018) and 60 (p=0,026) day. The geometric mean titers were lower in group 4 in relation to the others. Seroresponse after 6-month vaccination occurred in 19,7% to A/H1N1, 18% to A/H3N2 and 8.2% to B. There was no significant difference between the groups. CONCLUSION: Immunogenicity to influenza vaccine was poor in HSCT recipients. Donor or recipient vaccination strategy prior to transplantation increased the geometric mean titers only for subtype A/H3N2 at day 30 after transplant. No impact was observed in seroresponse rates after 6-month vaccination

Este estudo avaliou, quantitativamente, o osso regenerado após técnica de regeneração óssea guiada, utilizando osso autógeno em bloco e membrana de colágeno e descreveu seu processo de reparação ao redor de superfícies de implantes usinadas ou tratadas por jato de óxido de titânio em períodos de até 150 dias. Foram utilizados 60 ratos machos Wistar, divididos em 2 grupos: um recebeu implantes com superfície usinada (U) e o outro recebeu implantes com superfície tratada por jato de óxido de titânio (T). Uma trefina foi utilizada para a remoção do enxerto ósseo em bloco da calvária do animal. O enxerto foi fixado próximo ao ângulo da mandíbula do rato, na cortical vestibular, com o uso do implante. O conjunto foi coberto por membrana de colágeno. A ortotanásia foi realizada em 0, 14, 21, 45 e 150 dias. Foi realizado processamento histológico para material nãodescalcificado, e um corte no longo eixo do implante foi obtido para cada espécime. Foram realizadas análises qualitativa e quantitativa. Os dados foram analisados estatisticamente, em um nível de significância de 5%, pelos testes de Kruskal-Wallis e de Dunn. Os resultados relativos aos períodos de observação mostraram que a média do tamanho do defeito inicial foi de DO-U = 604,13 m e DO-T = 585,90 m (p=0,720) e que a média de espessura inicial do leito foi de EL-U = 257,29 m e ELT = 243,57 m (p=0,07); houve uma redução da espessura do enxerto no período de 150 dias para o grupo T em relação ao grupo U (EE-T = 338,25 m; EE-U = 407,71m) (p=0,003), não havendo outras diferenças significativas entre os grupos. Notou-se a presença de osso regenerado, vestibularmente ao enxerto, a partir de 21 dias, com uma nítida tendência ao aumento de sua espessura até o período de 150 dias, onde notamos um aumento da espessura óssea total de cerca de 4,6 (T) e 4,8 (U) vezes a espessura original da mandíbula, com valores de ETTO U = 1254,40 m e ETTO T = 1141,85 m (p=0,48). / This study quantitatively analyzed the regenerated bone after guided bone regeneration technique using autogenous block graft with resorbable membrane and described its pattern around machined titanium or oxide grit-blasted titanium surfaces in periods of up to 150 days. Sixty male, adult, Wistar rats were randomly assigned to one of two groups: machined titanium surface (U) or oxide grit-blasted titanium surface (T). A block graft was harvested from the rat calvarium with a trephine, laid and stabilized on the external cortex near the angle of the mandible with implants. A collagen membrane was adapted to completely cover the bone graft in both groups. The animals were euthanized at 0, 14, 21, 45 and 150 days after surgery. Nondecalcified histological sections were processed for each specimen and one section on the long axis of the implant was obtained. Qualitative and quantitative analysis were carried out. Statistical analyses were carried out with a significance level of 5% and used Kruskal-Wallis and Dunn tests. Results showed that the mean bone defect was DO-U = 604,13 m and DO-T = 585,90 m (p=0,720), and the mean mandible bone width was EL U = 257,29 m and EL-T = 243,57 m at zero hour. The mean graft width was reduced after 150 days for the T group as compared to group U (EET = 338,25 m and EE-U = 407,71 m) (p=0,003). No other significant differences between groups were observed. Regenerated bone was observed buccal to the bone graft after 21 days increasing in width after 150 days. The final mean mandible bone width after 150 days (ETTO-U = 1254,40 m and ETTO-T = 1141,85 m) achieved 4,8 (U) and 4,6 (T) times the original mandible width (p=0,48).

O transplante de células-tronco hematopoéticas tem surgido como alternativa ao tratamento de doenças autoimunes como artrite reumatóide, lúpus eritematoso sistêmico, esclerose múltipla e diabetes mellitus tipo 1. No diabetes mellitus tipo 1, uma síndrome de etiologia múltipla, o transplante de células-tronco hematopoéticas, na sua modalidade autóloga, tem sido utilizado como alternativa ao tratamento convencional (insulinoterapia), já que este retarda, mas não elimina as consequências da doença como disfunção e falência de vários órgãos, especialmente rins, olhos, nervos, coração e vasos sanguíneos. Apesar disso, o transplante é um procedimento altamente invasivo que acarreta repercussões intensas na qualidade de vida desses pacientes exigindo dos mesmos uma readaptação à essas repercussões. O presente estudo teve por objetivo avaliar a qualidade de vida e o ajustamento psicossocial de participantes com diabetes mellitus tipo 1. Participaram do estudo 22 pacientes que foram submetidos consecutivamente ao transplante de células-tronco hematopoéticas na Unidade de Transplante de Medula Óssea do Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo, no período de 2006 a 2008. Os instrumentos aplicados para a coleta de dados: Questionário Genérico de Avaliação de Qualidade de Vida Medical Outcomes Study 36 Item Short-Form Health Survey (SF-36), Escala de Ansiedade e Depressão Hospitalar - Hospital Anxiety and Depression Scale (HAD) e Inventário de Sintomas de Stress para Adultos de Lipp (ISSL). As avaliações ocorreram em três momentos distintos: na admissão do paciente, um ano após a realização do procedimento e dois anos após o transplante no retorno ambulatorial. A análise dos instrumentos aconteceu de acordo com as recomendações específicas preconizadas pela literatura. Os resultados obtidos mostraram, que para a maioria dos participantes deste estudo, após um ano do procedimento, os índices de qualidade de vida melhoraram significativamente principalmente os domínios Aspectos Físicos (p=0,0003), Estado Geral de Saúde (p=0,0142), Aspectos Sociais (p=0,0018) e Aspectos Emocionais (p=0,0316). Decorrido dois anos, o transplante teve um impacto também positivo sobre a qualidade de vida principalmente nos domínios Aspectos Físicos (p<0,0001), Aspectos Sociais (p=0,0235) e Aspectos Emocionais (p=0,0270). Em relação ao ajustamento psicossocial os resultados mostraram redução dos sintomas de ansiedade após o primeiro ano de transplante (p<0,01) e depressão nos dois momentos após o transplante (p<0,01). Observou-se ainda a diminuição dos sintomas de estresse nos momentos avaliados (p<0,01). Tais resultados podem representar uma possibilidade de retomada da vida e dos planos futuros que foram interrompidos por uma doença crônica que impunha inevitáveis dificuldades e limitações para esses participantes. Os resultados deste estudo oferecem subsídios para a equipe multidisciplinar de saúde refletir sobre as implicações dessa terapêutica inovadora em aspectos essenciais da vida do participante que vão além da dimensão biomédica, considerando as repercussões sobre sua qualidade de vida e ajustamento psicossocial. / Transplantation of hematopoietic stem cells has emerged as an alternative to the treatment of autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis and type 1 diabetes mellitus. In the latter, a syndrome of multiple etiology, the hematopoietic stem cell transplantation, in its autologous method, has been used as an alternative to conventional treatment (therapy with insulin), once it slows, but does not eliminate the consequences of the disease such as dysfunction and failure of various organs, especially kidneys, eyes, nerves, heart and blood vessels. Nevertheless, transplantation is a highly invasive procedure that carries severe repercussions on the quality of life of these patients, requiring from them a readjustment to these repercussions. The present study aimed to evaluate the quality of life and psychosocial adjustment of participants with type 1 diabetes mellitus. The study included 22 patients who underwent consecutive hematopoietic stem cell transplantation in the Bone Marrow Transplantation Ward of the Hospital das Clinicas of the University of Sao Paulo at Ribeirao Preto Medical School, between 2006 and 2008. The following instruments were used for data collection: Medical Outcomes Study 36 Item Short-Form Health Survey (SF-36), Hospital Anxiety and Depression Scale (HAD) and Lipp Stress Symptoms Inventory for Adults (LSSI). Assessments were performed at three different moments: at patient admission, one year after the performance of the procedure and two years after transplantation at the post-transplant outpatient clinic. Analysis of the instruments was done according to specific recommendations proposed in the literature. Results showed that, for most participants of the study, one year after the procedure, the indices of quality of life improved significantly, mainly the domains Physical Functioning (p=0.0003), General Health (p=0.0142), Social Functioning (p=0.0018) and Role-Emotional (p=0.0316). After two years, the transplant also had a positive impact on the quality of life, especially in the domains Physical Functioning (p<0.0001), Social Functioning (p=0.0235) and Role-Emotional (p=0.0270). In relation to psychosocial adjustment, results showed a reduction in symptoms of anxiety after the first year of transplantation (p<0.01) and depression at the two moments after transplantation (p<0.01). A decrease in symptoms of stress at the studied moments (p <0.01) was also observed. These results may represent a possibility of renewed life and future plans that were interrupted by a chronic illness that imposed inevitable difficulties and limitations to these participants. Results of this study provide support to the multidisciplinary health team reflect on the implications of this innovative therapy in essential aspects of participants life that go beyond the biomedical dimension, considering the repercussions on their quality of life and psychosocial adjustment.

As perdas ósseas em alguns seguimentos do sistema músculoesquelético têm sido motivo de grande preocupação na área da Ortopedia e Traumatologia. Propostas de tratamentos com uso de enxertos e fatores de crescimento são descritas ao longo dos anos. Neste estudo avaliamos o efeito do plasma rico em plaquetas -PRP na fase inicial do processo de osteointegração de enxertos ósseos homólogos criopreservados a - 80 °C, em forma de blocos, implantados no côndilo femoral de coelhos. Operamos 19 animais (38 fêmures), onde ambas as técnicas foram aplicadas no mesmo animal em lados alternados. De um lado aplicamos o aloenxerto isolado (Lado 1) e no outro associamos o aloenxerto ao PRP (Lado 2). Após 15 dias, os animais foram sacrificados e os côndilos femorais com as áreas de enxertia analisados pela histomorfometria com o método semiautomático. Não observamos efeito do plasma rico em plaquetas nas áreas de enxertias dos aloenxertos, pois a comparação dos parâmetros histomorfométricos estruturais, de formação e reabsorção não mostraram diferenças significativas. / Bone loss, in some segments of the muscle-skeleton system, are of great concern in the fields of Orthopedics and Traumatology. There are several options of treatment by means of bone grafts and growth factors. In this study we evaluate the effect of platelet rich plasma (PRP) in the initial phase of osteointegration of cryopreserved (- 80 °C) homologous bone grafts, in blocks, implanted in the femoral condyles of rabbits. We operated 19 animals (38 femurs). Both techniques were applied in the same animal in alternate sides. In one side we applied isolated allograft (side 1) and on the contralateral side we added PRP to the allograft (side 2). After 15 days, the animals were sacrificed and the femoral condyles, with the receptor area, were analyzed histomorphometrically (semi-automatic method). We found no effect of the PRP in the receptor. The comparison between the histomorphometric parameters of structural, formation and bone resorption showed no significant differences.

M.Cur. (Intensive General Nursing) / Knowledge and technological advancement in the field of transplantation has increased the demand for organ donation. However, the supply of organs does not meet this demand, especially, among the black communities. Literature reviewed associate this imbalance with the few sources of organs, the technique of organ retrieval, discrepancies in the allocation of organs and sociocultural factors. The aim of this study was to investigate the extent to which the Zulu cultural norms and social structural dimensions influence an individual's decision to donate an organ or to undergo a transplantation, based on the theoretical assumptions of Leininger and Chrisman. A qualitative approach using an ethno- nursing method was selected, semi-structured interviews were conducted with the transplant co-ordinator representing the professional sector, the religious leaders and traditional healers representing the folk sector and the general public representing the popular sector of the health care system. The respondents were extracted from both the urban and rural settings. The conclusions arrived at were that there is lack of knowledge among the Zulu speaking people on organ donation and transplantation, related mainly to misconceptions associated with their life patterns, beliefs about death, burial and life hereafter, values and social structural dimensions. The recommendations with regard to the promotion of organ donation and transplantation among the Zulu speaking people were made based on culture sensitive and culture congruent principles, namely: • Cultural care preservative or maintenance such as ancestor worship, extended families etc. • Cultural care accommodation or negotiation such as their knowledge of anatomy and physiology of the human body especially the transplantable organs and their fear to discuss death, etc. • Cultural care repatterning and restructuring such as culture sensitive educational campaigns to dispel the fears and correct misconceptions.

Une attention particulière doit être accordée aux jeunes patients transplantés du rein, qui sont prioritaires en France dans l’attribution de greffon rénal. Les objectifs de cette thèse étaient 1) d’étudier la dynamique du risque instantané de la perte du greffon en fonction de l’âge courant après la transplantation chez les jeunes ; 2) de réaliser un revue systématique des modèles de prédiction de perte du greffon rénal tout âge confondu; et 3) de développer et valider un modèle de prédiction adapté à cette jeune population. Pour répondre aux objectifs 1 et 3, nous avons utilisé les données des registres nationaux français REIN et CRITAL qui incluent de manière exhaustive tous les patients transplantés rénaux pédiatriques. Pour l’Objectif 1, une méthode statistique en deux étapes a permis de mettre en évidence une augmentation accrue du risque instantané de perte du greffon au moment de l’adolescence. Pour l’Objectif 2, une revue systématique des articles publiés entre 2005 et 2015 a montré qu’aucun outil prédictif de la perte du greffon n’avait été spécifiquement proposé pour les patients pédiatriques, ni aucun outil de prédiction dynamique tout âge confondu. Pour l’Objectif 3, nous avons développé et validé par validation croisée interne un modèle de prédiction dynamique de perte du greffon pour les jeunes transplantés, à partir d’un modèle conjoint à effets aléatoires partagés. Ce modèle incluait des prédicteurs classiques à l’inclusion défini par le 90ième jour après la transplantation (des caractéristiques du receveur (sexe, âge à la transplantation, durée de dialyse pré-greffe, maladie rénale initiale, nadir du DFGe entre la transplantation et J90), du donneur (âge, type), et de la transplantation (durée d’ischémie froide, nombre d’incompatibilités HLA, statut donneur/receveur pour sérologie CMV)). Le modèle incluait également la trajectoire du DFG estimé après la transplantation, en supposant que le risque instantané de perte du greffon dépendait à la fois du niveau courant du DFG mais aussi de sa pente courante. Nos résultats indiquent que ce modèle avait de bonnes performances prédictives (AUC à 5 ans variant de 0.75 à 0.86 selon les temps de prédiction après la transplantation), bien meilleures que le modèle de Cox classique ne tenant compte que des prédicteurs à l’inclusion (AUC à 5 ans variant de 0.56 à 0.62). Ce modèle permettant la mise à jour à chaque visite clinique après la transplantation, du risque futur de la perte du greffon en fonction de toutes les valeurs observées précédentes du DFG, devra être validé sur d’autres populations que la population française. Nous pensons en effet qu’un tel outil pourrait à terme être utile dans le suivi clinique des jeunes patients transplantés rénaux. / Particular attention should be paid to young patients transplanted from the kidney, which have priority in France in the assignment of renal graft. The objectives of this thesis were 1) to study the dynamics of the hazard of graft failure by current age after transplantation in young people; 2) to carry out a systematic review of prediction models for renal graft failure at all ages; and (3) to develop and validate a prediction model for this young population. To achieve Objectives 1 and 3, we used data from the French national registries REIN and CRISTAL, which included all pediatric renal transplant patients. For Objective 1, a two-stage statistical method revealed an increase in the hazard of graft failure during adolescence. For Objective 2, a systematic review of articles published between 2005 and 2015 showed that no predictive tool for graft failure has been specifically proposed for pediatric patients, as well as no dynamic predictive model for any age. For Objective 3, we developed and validated using internal cross-validation a dynamic prediction model of graft failure for young transplanted patients, using a joint model with shared random effects. This model included standard baseline predictors at the 90th day after transplantation (characteristics of the recipient (sex, age at transplantation, pretrasplant dialysis duration, primary renal disease, nadir of eGFR at J90), the donor (age and type), and transplantation (duration of cold ischemia, number of HLA incompatibilities, donor/recipient cytomegalovirus (CMV) serology status). The model also included the trajectory of GFR estimated after transplantation, assuming that the hazard of graft failure depended on both the current value of eGFR and its current slope. Our results indicate that this model had good predictive performances (AUC at 5 years ranging from 0.75 to 0.86 according to the time at prediction after transplantation), which were much better than the standard Cox model accounting for baseline predictors only (5-year AUC variant from 0.56 to 0.62). This model which allows the prediction of graft failure to be updated at each clinical visit after transplantation based on all previous observed values of eGFR, should be validated on populations other than the French population. We believe that such a tool could ultimately be useful in the clinical follow-up of young kidney transplanted patients.

La transplantation d’îlots pancréatiques offre un traitement potentielle pour le diabète de type 1 (T1DM). À ce jour, le succès mitigé de ce type de greffe est dû à plusieurs facteurs limitants comme le manque de revascularisation, la perte de la matrice extracellulaire (ECM) et le rejet par le système immunitaire du receveur. Dans les dernières années, l’utilisation de matrices tridimensionnelles (3D) et de bioréacteurs a amélioré le processus de transplantation et approfondi les connaissances sur le sujet. Le but de cette thèse est de mieux comprendre les effets des paramètres physiologiques (flux, concentration en oxygène dissous (D.O.) et pulsation) sur le tissu pancréatique dans un environnement 3D en utilisant un bioréacteur à perfusion. Le premier chapitre présente une revue de la littérature détaillant le pancréas, les maladies qui lui sont associées ainsi que les techniques permettant son étude in vitro et in vivo. L’utilisation de matrices 3D en recherche sur le diabète est discutée en profondeur tout en mettant l’emphase sur l’incorporation de molécules de la ECM. La revue souligne comment des matrices 3D testées en combinaison avec différents bioréacteurs ont permis de mieux comprendre et améliorer la culture de cellules pancréatiques. Une brève conclusion met en lumière les applications futures des bioréacteurs dans la recherche sur le diabète. La première étude de cette thèse traite de la culture de cellules de rat provenant d’insulinome (INS-1), encapsulées dans des matrices de fibrine en chambres de perfusion et cultivées dans un bioréacteur à perfusion. Un essai in situ de sécrétion d’insuline stimulée par le glucose fut développé pour comprendre les effets de la culture. Dans cette expérience, les effets bénéfiques des conditions contrôlées en bioréacteur à perfusion ont été démontrés et ont révélé une augmentation de l`indice de stimulation des cellules INS-1 avec le temps, une amélioration de la fonction GRIP, en plus d’une incidence moins élevée d’apoptose cellulaire en comparaison avec des témoins en culture statique, sans bioréacteur. Cette étude a été publiée dans la revue Biotechnology Progress. La deuxième étude décrit un design multifactoriel servant à l’identification des paramètres affectant des pancréas de rat dissociés mécaniquement, cultivés dans un bioréacteur à perfusion. Les effets uniques et combinés du flux, de la D.O. et de la pulsation ont été étudiés sur la culture de tissu pancréatique. Les conditions bénéfiques pour la culture en bioréacteur ont été identifiées. Le tissu pancréatique cultivé dans ces conditions bénéfiques a démontré une sécrétion d’insuline stimulée par le glucose, une plus grande activité métabolique, une coloration positive à l’insuline et au glucagon, des structures endothéliales multiples ainsi qu’un tissu plus intact en comparaison avec des cultures statiques cultivées en mode statique. Cette étude a été soumise à Biotechnology Progress. / Abstract : Transplantation of pancreatic islets offers a potential cure for type 1 diabetes mellitus (T1DM). To date, the success of such a graft has been mired by a number of limiting factors including lack of revascularisation, loss of native extracellular matrix (ECM), and graft rejection by the recipient’s immune system. In recent years, new ways to understand and improve this process have been explored using three-dimensional (3D) matrices and bioreactors. This thesis aims to further understand the important effect(s) physiological parameters (flow, dissolved oxygen concentration (D.O.) and pulsation) have on pancreatic tissue in a 3D environment using a perfusion bioreactor with defined geometries. The first chapter introduces a review of the literature detailing the native pancreas, its diseases, and how it is studied in vivo and in vitro. The use of 3D matrices in diabetes research is discussed with particular emphasis on the incorporation of ECM molecules. The review then highlights how 3D matrices have been used in combination with a host of different bioreactors to understand and improve pancreatic cell cultures. A brief conclusion about the future applications for the use of bioreactors in diabetes research is also discussed. The first experimental work comprises the culture of rat insulinoma cells (INS-1) encapsulated in fibrin matrices in perfusion chambers and cultured under perfusion bioreactor conditions. An in situ glucose-stimulated insulin secretion assay was then developed to monitor the culture over time. With this work, the beneficial effects of perfusion bioreactor conditions were shown and revealed increasing functionality (glucose-stimulated insulin secretion) of INS-1 cells over time, and a lower incidence of apoptosis when compared to static control cultures. This study was published in Biotechnology Progress. The second experimental work used a factorial design to identify process parameters affecting whole mechanically-disrupted rat pancreata in a perfusion bioreactor. Here, the singular and combinational effects of flow, dissolved oxygen concentration and pulsation were assessed on the outcome of pancreatic tissue. Beneficial bioreactor conditions were identified. Mechanically-disrupted rat pancreata cultured under these beneficial bioreactor conditions showed glucose-stimulated insulin secretion, higher metabolic activity, insulin- and glucagon-positive staining, extensive endothelial structures, and overall intact tissue when compared to static cultures. This study has been submitted to Biotechnology Progress.

La méthode de préservation d’organes la plus utilisée actuellement en transplantation rénale est la conservation statique en hypothermie. Cependant, ce mode de conservation induit des dommages inhérents aux lésions du syndrome d’ischémie/reperfusion (I/R). Cette étude a eu pour objectif d’identifier de nouvelles conditions de préservation des greffons, afin de limiter les lésions d’I/R, en modulant la température de conservation ou par ajout d’un transporteur d’oxygène. Nous avons utilisé deux modèles : in vitro avec des cellules endothéliales et in vivo en autotransplantation rénale chez le porc.Les résultats ont confirmé les effets délétères de la conservation à 4°C contrairement à des conservations à 19°C, 27°C et surtout 32°C, permettant d’obtenir une activité métabolique, une viabilité et une intégrité cellulaire supérieures ainsi qu’une diminution des marqueurs de l’inflammation et du stress oxydant. Nous avons aussi démontré les bénéfices d'un nouveau transporteur d’oxygène, M101, dans deux des solutions de conservation les plus utilisés, UW et HTK. L'utilisation de M101 en conservation statique permet une meilleure reprise de fonction à court terme et une réduction de la fibrose, cause principale de la perte du greffon. Enfin, nous avons montré une conservation des bénéfices de M101 à des doses réduites et déterminé que cette protection était due à une multifonctionnalité de la molécule, combinant un transporteur d’oxygène, une activité superoxyde dismutase et une taille importante (permettant de réguler la pression oncotique). Ce travail a montré de nouvelles pistes de réflexion vers une préservation, et donc une qualité, supérieure des organes à transplanter. / The most used preservation method in renal transplantation is hypothermic cold storage (CS). However, this method induces damages inherent to the ischemia/ reperfusion (I /R) syndrome.My study was aimed at identifying new grafts preservation conditions, to limit I/R damage, by varying storage temperature or by adding an oxygen carrier.We used two models: in vitro with endothelial cells and in vivo in pig renal autotransplantation. The results confirmed the deleterious effects of 4°C storage in contrast to conservations at 19°C, 27°C and above 32°C, resulting in improved metabolic activity, cellular viability and integrity as well as a significant reduction in markers of inflammation and oxidative stress. Then we demonstrated the benefits of a new oxygen carrier, M101, in the two most used preservation solutions, UW and HTK. Indeed, use of M101 in CS protocols improved short-term function recovery and reduced fibrosis development, main cause of graft loss. Finally, we have shown that the benefits of M101 were preserved at lower doses and we determined that this protection was due to a multifunctionality of the molecule, combining oxygen transport, superoxyde dismutase activity and a large size (regulating oncotic pressure). This work permitted the uncovering of new concepts towards improved organ preservation and quality for transplantation.

Actuellement les transplanteurs sont confrontés à une pénurie de greffons, conduisant à l'élargissement des critères de choix des donneurs. Cette démographie fait place à des greffons plus sensibles aux lésions d'ischémie-reperfusion (I/R). Ces lésions conduisent à des dysfonctions de reprises de fonction des greffons, et participent à l'augmentation de l'immunogénicité du greffon et à l'emergence de rejets aigus et chroniques. Dans un premier temps, il est donc nécessaire de limiter les lésions d'I/R et conserver l'intégrité du greffon. Dans un deuxième temps, il est important de réduire l'immunogénicité du greffon et de contrôler le rejet de greffe tout en maintenant le receveur immunocompétent. Afin de limiter les lésions d'I/R nous avons évalué la solution de préservation SCOT de type extracellulaire contenant 30g/L de PEG 20kDa, dans un modèle murin d'isolement et de transplantation d'îlots pancréatiques. L'amélioration des conditions de conservation a permit de préserver l'intégrité des îlots et de réduire l'immunogénicité du greffon, et ce due aux propriétés immunoprotectrices des PEG 20kDa (effets obtenus pour 10 à 30g/L). Dans ce même modèle notre second objectif était d'établir un état de tolérance périphérique par déplétion transitoire des lymphocytes T alloréactifs. La déplétion des lymphocytes T en division a été induite au moment de l'allotransplantation des îlots, par administration transitoire d'un analogue nucleosidique inductible. La déplétion transitoire a permit d'aboutir à une immunotolérance dominante via l'émergence de lymphocytes T régulateurs CD4+CD25+FoxP3+, cellules ouvrant de nouvelles perspectives dans l'inhibition des rejets d'allogreffes. / Organ and tissue transplantation is affected by a shortage of grafts, leading to enlargement of donor criteria. Consequently, these new marginal organs are more susceptible to ischemia-reperfusion injury (IRI). IRI increases primary graft dysfunctions and contributes to increase graft immunogenicity and consequently the occurence of acute and chronic rejection. Our objectives were : firstly, the necessity to limit I/R damages and preserve graft integrity, secondly, the importance to reduce graft immunogenicity and control the graft rejection while maintaining an immunocompetent recipient. To limit IRI we evaluated the new SCOT preservation extracellular type solution containing PEG 20kDa 30g/L in a murine model of pancreatic islets isolation and transplantation. The improvement of conservation with SCOT permitted to maintain the islets integrity and to reduce graft immunogenicity, due to the immunoprotective properties of PEG 20kDa (effects obtained with PEG 20kDa at 10 to 30g /L). In this same model our second objective was to establish a peripheral immunological tolerance of the graft by transient depletion of alloreactive T cells. This depletion of T cells in division was induced at the time of islet allotransplantation by an administration of an inducible nucleosidic analogue during 14 days. Transient alloreactive T cells depletion induced a dominant immunotolerance marked by the emergence of a persistent regulatory T cells CD4+CD25+FoxP3+ population. Thus, regulation of homeostatic balance between effector and regulatory T cells could open an interesting way to control the immune reaction against allograft.

Les lésions cérébrales induisent une mort neuronale associée à des déficits fonctionnels importants. Afin de pallier aux capacités limitées de régénération spontanée des neurones du système nerveux central adulte, nous avons évalué, dans un modèle de lésion par aspiration du cortex moteur chez la souris adulte, le potentiel de stratégies de remplacement cellulaire par la transplantation de neurones embryonnaires ou dérivés de cellules souches, et la mobilisation des cellules souches endogènes présentes dans la zone sous-ventriculaire (ZSV). L'efficacité des neurones greffés dépend de leur capacité à adopter un phénotype neuronal approprié et à établir des projections spécifiques vers l'hôte. Nous avons montré que les cellules embryonnaires transplantées immédiatement après la lésion dans le cortex moteur lésé se différencient en neurones matures corticaux et envoient des projections appropriées vers les cibles du cortex moteur. Nous avons montré qu'introduire un délai d'une semaine entre la lésion du cortex moteur et la transplantation augmente la vascularisation et la prolifération des cellules transplantées, ainsi que la densité des projections qu'elles développent. Par ailleurs, nous avons étudié la possibilité de générer des neurones corticaux à partir de cellules souches humaines comme source alternative de neurones à transplanter. Enfin, nous avons montré que la lésion du cortex moteur induit une augmentation de la prolifération cellulaire et de la neurogenèse dans la ZSV, et favorise la migration des neuroblastes de la ZSV vers le site de lésion. / Damage to the adult motor cortex can lead to severe deficits in motor function. One strategy for overcoming the generally limited capacity of the mature central nervous system to regenerate axons in response to cell loss is cell replacement based therapies. We studied brain repair strategies in a mouse model of motor cortex aspiration lesion by using transplantation of embryonic neurons or stem cells-derived neurons and by evaluating the potential of endogenous stem cells found in the subventricular zone. Neuronal transplantation efficacy depends on the capacity of the transplanted cells to developp into appropriate neuronal phenotype and establishment of specific connections. We have shown that embryonic cells grafted immediately after lesion into the lesioned motor cortex develop into mature neurons with appropriate phenotype and establish projections towards appropriate targets. We have shown that introducing a delay of one week between motor cortex lesion and transplantation enhances graft vascularization, grafted cells proliferation and the density of transplant-to-host projections. Besides, we have studied the possibility to generate cortical neurons from human stem cells as an alternative source of neurons for transplantation. Finally, recruitment of endogenous stem cells found in the SVZ was examined in a mouse model of cortical lesion. We have shown that motor cortex injury increases cellular proliferation and neurogenesis in the SVZ and the migration of neuroblasts near the lesion site via blood vessels and astrocytes assisted migration.