Cardiovascular diseases are the leading cause of death throughout the world and various estimates predict that heart disease will remain the number one killer in the world. Pharmacotherapies have not shown significant long term survival benefits to the patients, therefore alternate therapeutic strategies such as bioactive agent delivery and cell therapy based approaches are being investigated. One of the major causes of heart failure is the disease progression after an ischemic event and any successful therapy will be needed over the course of several days/weeks. Oxidative stress is greatly increased in the myocardium following infarction. This plays a significant role in cardiac disease progression and it has also been implicated in the failure of implanted cell therapy. Therefore, reducing oxidative stress in damaged tissue using antioxidants may have broad clinical implications for both the treatment of cardiac dysfunction and for cardiac regeneration applications. This dissertation work examines the effect of sustained delivery of endogenous antioxidant superoxide dismutase (SOD) to the rat myocardium following ischemia/reperfusion (IR) using polyketal polymers as drug carriers. The second major objective of this dissertation is to examine the effects of oxidative stress on cardiac progenitor cells - a promising endogenous adult stem cell in cardiac cell therapy applications

Plusieurs populations de cellules immunitaires possèdent une activité cytotoxique permettant l'élimination de cellules altérées. Cette fonction cellulaire est ainsi déterminante dans le contrôle des infections, des processus tumoraux, ou encore des maladies inflammatoires chroniques. Mon projet de thèse se concentre sur des aspects fondamentaux de l'activité lytique de deux populations de lymphocytes T cytotoxiques : les lymphocytes T CD8+ et les lymphocytes T CD4+ régulateurs de type 1. Pour cela, l'exploration des mécanismes de cette activité a été conduite au travers de deux modèles, pathologique et thérapeutique, à différentes échelles biologiques : au niveau de la population ou de la cellule individuelle, mais aussi différentes échelles d'organisations moléculaires : cellulaire et nanoscopique. Nous avons pu démontrer que l'activité de lyse de lymphocytes T CD8+ cytotoxiques face à un excès de cellules cibles est efficace sur des temps prolongés, reposant sur une capacité individuelle fortement hétérogène à effectuer une lyse multiple. L'importance de cette activité de lyse soutenue a été renforcée par l'identification d'un défaut lytique particulièrement prononcé sur le long- terme chez des lymphocytes T CD8+ issus de patients atteints du syndrome de Wiskott-Aldrich. Ce défaut est lié à une activation réduite de l'intégrine LFA-1 et un délai dans la délivrance du coup létal. De plus, la protéine WASP permet de restreindre LFA-1 de haute-affinité en nanoclusters denses ainsi que de permettre l'organisation en un ring de LFA-1 et la localisation des granules lytiques à l'intérieur de celui-ci. Par ailleurs, les lymphocytes T CD4+ régulateurs de type 1 développés dans le cadre d'une thérapie cellulaire (Ovasave(r)) démontrent une capacité de lyse envers les cellules myéloïdes, en complément d'une activité immunosuppressive sur les lymphocytes T conventionnels. Cette activité est mise en place sur du long-terme, jusqu'à atteindre une efficacité optimale, lié à un délai dans la délivrance du coup létal. De manière surprenante, malgré une spécificité pour l'ovalbumine, l'activité cytotoxique semble être indépendante de l'activation du TCR. En outre, la lyse est granzyme-dépendante mais perforine-indépendante. Ainsi ces lymphocytes T thérapeutiques manifestent une activité cytotoxique alternative. Pour conclure, mon projet de thèse a permis de caractériser une activité de lyse soutenue basée sur une capacité individuelle hétérogène. Cette habilité à soutenir une lyse sur du long-terme implique une stabilité de la synapse, où WASP joue notamment un rôle clé pour l'activation et l'organisation de LFA-1. Les lymphocytes T régulateurs thérapeutiques démontrent aussi une activité de lyse soutenue, cependant les acteurs moléculaires sont non conventionnels. De manière générale, une activité de lyse soutenue permettrait de calibrer une réponse cytotoxique prolongée en rapport à la taille de la population cible, ainsi que le partage avec d'autres fonctions cellulaires comme la sécrétion de cytokines. / During different pathological conditions such as infections, tumoral processes or chronic inflammation diseases, altered cells are eliminated through a cytotoxic activity mediated by several immune cell populations. This cellular function is therefore crucial for carrying out the action of the immune system. My thesis project focuses on fundamental aspects of the lytic activity of two cytotoxic lymphocyte populations: CD8+ T cells and type-1 CD4+ regulatory T cells. To explore the mechanisms of this activity, this study has been driven on two cases, pathological and therapeutic models, at the population and single-cell levels and also at the cellular and nanoscopic scales of the molecular organisation. We have been able to demonstrate that the CD8+ T cell lysis activity against an excess of target cells is effective over prolonged periods, relying on a highly heterogeneous individual capacity to perform multiple lysis. The importance of this sustained cytotoxic activity was reinforced by the identification of a lytic defect, particularly pronounced on a long time period, of CD8+ T cells from Wiskott-Aldrich syndrome patients. This defect is related to a reduced activation of the LFA-1 integrin and delay in the lethal hit delivery. In addition, the WASP protein allows to restrict high affinity LFA-1 to dense nanoclusters as well as the assembly of LFA- 1 ring and the localization of the lytic granules inside this ring. Moreover, type-1 CD4+ regulatory T cells from a cellular therapy (Ovasave(r)) demonstrated a cytotoxic activity toward myeloid cells, additionally to an immunosuppressive activity on conventional T cells. This activity is implemented over long time periods, until reaching optimal efficiency, and is related to a delay in the lethal hit delivery. Surprisingly, despite a specificity for ovalbumin, the cytotoxic activity measured in absence of the antigen suggests a TCR independence. In addition, lysis is not mediated by perforin but is exclusively granzyme-dependent. Thus, these therapeutic T cells exhibit an alternative cytotoxic activity. To conclude, my thesis project permits to characterize a sustained lysis activity relying on a heterogeneous individual capacity. This ability to sustain a lytic activity involves stability of the synapse, where WASP plays a key role towards the activation and organization of LFA-1. The therapeutic regulatory T lymphocytes also demonstrated a sustained cytotoxic activity, however the molecular actors are unconventional. On the whole, sustained lytic activity would be key to the calibration of cytotoxic responses in relation to the size of the target population, as well as sharing with other cellular functions such as cytokine secretion.

A terapia celular utilizando células tronco-mesenquimais (MSCs) surge como alternativa para o tratamento das doenças inflamatórias intestinais (DII). Atualmente, os métodos terapêuticos consistem principalmente na utilização de fármacos que visam produzir e manter estados de remissão da colite ulcerativa e, muitas vezes, apresentam efeitos colaterais. Considerando a capacidade de modular células do sistema imune e de regenerar tecidos doentes, as MSCs podem ser consideradas uma alternativa para o tratamento de DII, como a colite ulcerativa. Além disso, muito tem se investigado a respeito do homing de MSCs exógenas infundidas por diversas vias em resposta a um insulto inflamatório e tem-se visto a capacidade de migração para tecidos afetados. A primeira etapa do trabalho consistiu na caracterização e desenvolvimento do modelo animal de colite ulcerativa aguda. Para isso, foram testados diferentes pesos moleculares e concentrações do reagente Dextran Sulfato de Sódio (DSS), a fim de verificar qual o melhor método de indução da doença. Após determinar o adequado modelo animal, que utilizou 2% DSS (36 000 – 50 000 Da), foi iniciado o experimento de terapia celular. Na tentativa de compreender como as MSCs podem influenciar a inflamação intestinal, o estudo avaliou o efeito do transplante de MSCs derivadas do tecido adiposo em duas diferentes vias de infusão, intraperitoneal e intravenosa, em modelo murino experimental de colite aguda. Foram avaliados os seguintes parâmetros: atividade clínica da doença, aspecto macroscópico e histopatológico do cólon, dosagem de citocinas inflamatórias, taxas de apoptose e parâmetros de estresse oxidativo. Os resultados obtidos no trabalho mostraram que o transplante celular intravenoso melhorou a severidade clínica de colite, como perda de peso, diarreia e presença de sangue nas fezes. Na avaliação histológica, observou-se a diminuição da inflamação colônica através da redução de perda de criptas e de infiltração de células inflamatórias. Ainda, os fatores secretados pelas MSCs parecem poder reduzir os níveis de IL-6 e aumentar os níveis de IL-10 e IL-4 do soro. Um aumento de células apoptóticas foi observado nos animais tratados com MSCs por via intravenosa, sugerindo que as MSCs induzem morte celular em células T resistentes à apoptose. Além disso, a terapia intravenosa foi capaz de aumentar os níveis de glutationa reduzida, um importante antioxidante natural, revertendo o dano causado pelo estresse oxidativo no cólon. Em conjunto, nossos resultados demonstram que a melhor via para a terapia celular na colite ulcerativa foi a intravenosa e que o tratamento proposto foi eficaz no que se refere à redução da inflamação do cólon. / Mesenchymal stem cell (MSC) therapy is an alternative for the treatment of inflammatory bowel disease (IBD). Currently, therapeutic methods consist primarily on the use of drugs which aim to produce and maintain state of ulcerative colitis remission and often present side effects. Considering the ability to modulate the immune system cells and regenerate injuried tissues, MSCs can be considered an alternative for treating IBD, such as ulcerative colitis. Moreover, there is many research investigating the homing of exogenous MSCs infused through different routes in response to an inflammatory insult, and has demonstrated the migration capacity of these cells into the affected tissues. The first stage of this study consisted in the characterization and development of acute animal model of ulcerative. For this, different molecular weights and concentrations of Dextran Sulfate Sodium (DSS) reagent were tested in order to verify the best method for disease induction. After determining the appropriate animal model, that uses 2% DSS (36000-50000 Da), the cell therapy experiment was initiated. In an attempt to understand how MSCs can influence intestinal inflammation, the study evaluated the effect of MSCs transplantation using two different infusion routes, intraperitoneal and intravenous, in an acute colitis murine model. The following parameters were evaluated: clinical disease activity, colon macroscopic and histological analysis, serum inflammatory cytokine, determination apoptosis rates and oxidative stress parameters. Results show that MSC intravenous transplantation has improved the clinical severity of colitis, such as weight loss, diarrhea, and blood stool. Histological evaluation demonstrated a decreased colonic inflammation by reducing colonic crypt loss and infiltration of inflammatory cells. Also, MSCs secreted factors which seem to reduce levels of IL-6 and increase levels of IL-10 and IL-4 in the serum. In addition, an increase of apoptotic cells was observed in animals treated with intravenous MSCs, suggesting that MSCs induce cell death in T cells resistant to apoptosis. Furthermore, intravenous therapy was able to increase the levels of reduced glutathione, an important natural antioxidant, reversing the damage caused by oxidative stress in the colon. Taken together, our results demonstrate that the best route for cell therapy in ulcerative colitis was intravenous and the proposed treatment was effective with regards to reducing colon inflammation.

A cirurgia endoscópica transluminal por orifícios naturais (NOTES) é uma nova modalidade cirúrgica caracterizada pela ausência de incisões cutâneas. Diferentes vias de acesso para a NOTES já foram testadas, porém, existem poucos estudos sobre os efeitos imunomoduladores da via transretal e de sua associação com as células-tronco mesenquimais (MSCs) como adjuvante nos efeitos anti-inflamatórios e na cicatrização retal. Este trabalho objetivou avaliar a exequibilidade da técnica NOTES transretal, os efeitos imunomodulatórios e regenerativos desta abordagem cirúrgica e sua associação com as MSCs em um modelo experimental suíno. A tese foi divida em quatro capítulos sendo que o primeiro trata de uma revisão bibliográfica sobre as vias de acesso para a NOTES e suas implicações. O segundo objetivou testar a exequibilidade da via transretal em três suínos, o que demonstrou ser um acesso alternativo para procedimentos abdominais. O terceiro capítulo avalia a resposta inflamatória da técnica NOTES e da sua associação com MSC derivadas de tecido adiposo. Para isso, 11 suínos foram submetidos a NOTES transretal e distribuídos aleatoriamente em dois grupos: GNOTES e GNOTES+MSC. Amostras de sangue foram coletadas em diferentes tempos para exames de hemograma, albumina, proteína C reativa (PCR) e interleucina- 6 (IL-6). Não houveram alterações entre os grupos quanto aos valores de hemograma, albumina e PCR, sendo que a IL-6 foi indetectável em todos os animais. Histologicamente, foi observado menor quantidade de células inflamatórias no GNOTES+MSC na camada muscular. Estes dados sugerem que tanto a técnica NOTES quanto as MSCs atenuam os efeitos inflamatórios do procedimento. Um prolapso retal ocorrido como complicação da técnica NOTES transretal foi detalhadamente descrito no quarto capítulo. Assim, a técnica NOTES associada ou não às MSCs no sítio da incisão apresenta mínima resposta inflamatória em suínos submetidos à peritoneoscopia transretal. / Natural orifice transluminal endoscopic surgery (NOTES) is an evolving surgical approach to be performed without skin incisions. Different access sites have been tested, however, studies regarding immunomodulation of the transrectal approach and its association with mesenchymal stem cells (MSC) are still lacking. The viability of transrectal NOTES and the associated effects of MSC local therapy on rectal healing and inflammation were tested in a porcine model. The results of the study are depicted in fours chapters. The first chapter presents a literature review and state-of-the-art on the accesses for NOTES. The subsequent paper describes the transrectal approach performed in three pigs and its viability as an alternative access to abdominal endoscopic procedures. In the third chapter, the evaluation of the inflammatory response with transrectal NOTES and adipose tissue MSC therapy is presented. For that, 11 pigs were either submitted to NOTES only or NOTES with local MSC application. Blood samples, peritoneal fluid, and post-mortem rectal tissue specimens were collected. Total blood count, albumin and C-reactive protein showed no significant differences between groups. Interleukin-6 was undetectable in both groups. Histological evaluations demonstrated less inflammatory cells in the muscular layer of rectum of the animals where NOTES was associated with MSC. A possible lessening of the immune response may be seen with NOTES with or without MSCs; however, the presence of MSC attenuate the local inflammatory reaction in the muscular layer of porcine rectum after transrectal NOTES. A rectal prolapse that occurred after transrectal NOTES in one pig is reported in the last chapter. The transrectal NOTES technique with or without the MSCs at the incision site shows minimal inflammatory response in porcine.

A terapia celular utilizando células tronco-mesenquimais (MSCs) surge como alternativa para o tratamento das doenças inflamatórias intestinais (DII). Atualmente, os métodos terapêuticos consistem principalmente na utilização de fármacos que visam produzir e manter estados de remissão da colite ulcerativa e, muitas vezes, apresentam efeitos colaterais. Considerando a capacidade de modular células do sistema imune e de regenerar tecidos doentes, as MSCs podem ser consideradas uma alternativa para o tratamento de DII, como a colite ulcerativa. Além disso, muito tem se investigado a respeito do homing de MSCs exógenas infundidas por diversas vias em resposta a um insulto inflamatório e tem-se visto a capacidade de migração para tecidos afetados. A primeira etapa do trabalho consistiu na caracterização e desenvolvimento do modelo animal de colite ulcerativa aguda. Para isso, foram testados diferentes pesos moleculares e concentrações do reagente Dextran Sulfato de Sódio (DSS), a fim de verificar qual o melhor método de indução da doença. Após determinar o adequado modelo animal, que utilizou 2% DSS (36 000 – 50 000 Da), foi iniciado o experimento de terapia celular. Na tentativa de compreender como as MSCs podem influenciar a inflamação intestinal, o estudo avaliou o efeito do transplante de MSCs derivadas do tecido adiposo em duas diferentes vias de infusão, intraperitoneal e intravenosa, em modelo murino experimental de colite aguda. Foram avaliados os seguintes parâmetros: atividade clínica da doença, aspecto macroscópico e histopatológico do cólon, dosagem de citocinas inflamatórias, taxas de apoptose e parâmetros de estresse oxidativo. Os resultados obtidos no trabalho mostraram que o transplante celular intravenoso melhorou a severidade clínica de colite, como perda de peso, diarreia e presença de sangue nas fezes. Na avaliação histológica, observou-se a diminuição da inflamação colônica através da redução de perda de criptas e de infiltração de células inflamatórias. Ainda, os fatores secretados pelas MSCs parecem poder reduzir os níveis de IL-6 e aumentar os níveis de IL-10 e IL-4 do soro. Um aumento de células apoptóticas foi observado nos animais tratados com MSCs por via intravenosa, sugerindo que as MSCs induzem morte celular em células T resistentes à apoptose. Além disso, a terapia intravenosa foi capaz de aumentar os níveis de glutationa reduzida, um importante antioxidante natural, revertendo o dano causado pelo estresse oxidativo no cólon. Em conjunto, nossos resultados demonstram que a melhor via para a terapia celular na colite ulcerativa foi a intravenosa e que o tratamento proposto foi eficaz no que se refere à redução da inflamação do cólon. / Mesenchymal stem cell (MSC) therapy is an alternative for the treatment of inflammatory bowel disease (IBD). Currently, therapeutic methods consist primarily on the use of drugs which aim to produce and maintain state of ulcerative colitis remission and often present side effects. Considering the ability to modulate the immune system cells and regenerate injuried tissues, MSCs can be considered an alternative for treating IBD, such as ulcerative colitis. Moreover, there is many research investigating the homing of exogenous MSCs infused through different routes in response to an inflammatory insult, and has demonstrated the migration capacity of these cells into the affected tissues. The first stage of this study consisted in the characterization and development of acute animal model of ulcerative. For this, different molecular weights and concentrations of Dextran Sulfate Sodium (DSS) reagent were tested in order to verify the best method for disease induction. After determining the appropriate animal model, that uses 2% DSS (36000-50000 Da), the cell therapy experiment was initiated. In an attempt to understand how MSCs can influence intestinal inflammation, the study evaluated the effect of MSCs transplantation using two different infusion routes, intraperitoneal and intravenous, in an acute colitis murine model. The following parameters were evaluated: clinical disease activity, colon macroscopic and histological analysis, serum inflammatory cytokine, determination apoptosis rates and oxidative stress parameters. Results show that MSC intravenous transplantation has improved the clinical severity of colitis, such as weight loss, diarrhea, and blood stool. Histological evaluation demonstrated a decreased colonic inflammation by reducing colonic crypt loss and infiltration of inflammatory cells. Also, MSCs secreted factors which seem to reduce levels of IL-6 and increase levels of IL-10 and IL-4 in the serum. In addition, an increase of apoptotic cells was observed in animals treated with intravenous MSCs, suggesting that MSCs induce cell death in T cells resistant to apoptosis. Furthermore, intravenous therapy was able to increase the levels of reduced glutathione, an important natural antioxidant, reversing the damage caused by oxidative stress in the colon. Taken together, our results demonstrate that the best route for cell therapy in ulcerative colitis was intravenous and the proposed treatment was effective with regards to reducing colon inflammation.

A cirurgia endoscópica transluminal por orifícios naturais (NOTES) é uma nova modalidade cirúrgica caracterizada pela ausência de incisões cutâneas. Diferentes vias de acesso para a NOTES já foram testadas, porém, existem poucos estudos sobre os efeitos imunomoduladores da via transretal e de sua associação com as células-tronco mesenquimais (MSCs) como adjuvante nos efeitos anti-inflamatórios e na cicatrização retal. Este trabalho objetivou avaliar a exequibilidade da técnica NOTES transretal, os efeitos imunomodulatórios e regenerativos desta abordagem cirúrgica e sua associação com as MSCs em um modelo experimental suíno. A tese foi divida em quatro capítulos sendo que o primeiro trata de uma revisão bibliográfica sobre as vias de acesso para a NOTES e suas implicações. O segundo objetivou testar a exequibilidade da via transretal em três suínos, o que demonstrou ser um acesso alternativo para procedimentos abdominais. O terceiro capítulo avalia a resposta inflamatória da técnica NOTES e da sua associação com MSC derivadas de tecido adiposo. Para isso, 11 suínos foram submetidos a NOTES transretal e distribuídos aleatoriamente em dois grupos: GNOTES e GNOTES+MSC. Amostras de sangue foram coletadas em diferentes tempos para exames de hemograma, albumina, proteína C reativa (PCR) e interleucina- 6 (IL-6). Não houveram alterações entre os grupos quanto aos valores de hemograma, albumina e PCR, sendo que a IL-6 foi indetectável em todos os animais. Histologicamente, foi observado menor quantidade de células inflamatórias no GNOTES+MSC na camada muscular. Estes dados sugerem que tanto a técnica NOTES quanto as MSCs atenuam os efeitos inflamatórios do procedimento. Um prolapso retal ocorrido como complicação da técnica NOTES transretal foi detalhadamente descrito no quarto capítulo. Assim, a técnica NOTES associada ou não às MSCs no sítio da incisão apresenta mínima resposta inflamatória em suínos submetidos à peritoneoscopia transretal. / Natural orifice transluminal endoscopic surgery (NOTES) is an evolving surgical approach to be performed without skin incisions. Different access sites have been tested, however, studies regarding immunomodulation of the transrectal approach and its association with mesenchymal stem cells (MSC) are still lacking. The viability of transrectal NOTES and the associated effects of MSC local therapy on rectal healing and inflammation were tested in a porcine model. The results of the study are depicted in fours chapters. The first chapter presents a literature review and state-of-the-art on the accesses for NOTES. The subsequent paper describes the transrectal approach performed in three pigs and its viability as an alternative access to abdominal endoscopic procedures. In the third chapter, the evaluation of the inflammatory response with transrectal NOTES and adipose tissue MSC therapy is presented. For that, 11 pigs were either submitted to NOTES only or NOTES with local MSC application. Blood samples, peritoneal fluid, and post-mortem rectal tissue specimens were collected. Total blood count, albumin and C-reactive protein showed no significant differences between groups. Interleukin-6 was undetectable in both groups. Histological evaluations demonstrated less inflammatory cells in the muscular layer of rectum of the animals where NOTES was associated with MSC. A possible lessening of the immune response may be seen with NOTES with or without MSCs; however, the presence of MSC attenuate the local inflammatory reaction in the muscular layer of porcine rectum after transrectal NOTES. A rectal prolapse that occurred after transrectal NOTES in one pig is reported in the last chapter. The transrectal NOTES technique with or without the MSCs at the incision site shows minimal inflammatory response in porcine.

A terapia celular utilizando células tronco-mesenquimais (MSCs) surge como alternativa para o tratamento das doenças inflamatórias intestinais (DII). Atualmente, os métodos terapêuticos consistem principalmente na utilização de fármacos que visam produzir e manter estados de remissão da colite ulcerativa e, muitas vezes, apresentam efeitos colaterais. Considerando a capacidade de modular células do sistema imune e de regenerar tecidos doentes, as MSCs podem ser consideradas uma alternativa para o tratamento de DII, como a colite ulcerativa. Além disso, muito tem se investigado a respeito do homing de MSCs exógenas infundidas por diversas vias em resposta a um insulto inflamatório e tem-se visto a capacidade de migração para tecidos afetados. A primeira etapa do trabalho consistiu na caracterização e desenvolvimento do modelo animal de colite ulcerativa aguda. Para isso, foram testados diferentes pesos moleculares e concentrações do reagente Dextran Sulfato de Sódio (DSS), a fim de verificar qual o melhor método de indução da doença. Após determinar o adequado modelo animal, que utilizou 2% DSS (36 000 – 50 000 Da), foi iniciado o experimento de terapia celular. Na tentativa de compreender como as MSCs podem influenciar a inflamação intestinal, o estudo avaliou o efeito do transplante de MSCs derivadas do tecido adiposo em duas diferentes vias de infusão, intraperitoneal e intravenosa, em modelo murino experimental de colite aguda. Foram avaliados os seguintes parâmetros: atividade clínica da doença, aspecto macroscópico e histopatológico do cólon, dosagem de citocinas inflamatórias, taxas de apoptose e parâmetros de estresse oxidativo. Os resultados obtidos no trabalho mostraram que o transplante celular intravenoso melhorou a severidade clínica de colite, como perda de peso, diarreia e presença de sangue nas fezes. Na avaliação histológica, observou-se a diminuição da inflamação colônica através da redução de perda de criptas e de infiltração de células inflamatórias. Ainda, os fatores secretados pelas MSCs parecem poder reduzir os níveis de IL-6 e aumentar os níveis de IL-10 e IL-4 do soro. Um aumento de células apoptóticas foi observado nos animais tratados com MSCs por via intravenosa, sugerindo que as MSCs induzem morte celular em células T resistentes à apoptose. Além disso, a terapia intravenosa foi capaz de aumentar os níveis de glutationa reduzida, um importante antioxidante natural, revertendo o dano causado pelo estresse oxidativo no cólon. Em conjunto, nossos resultados demonstram que a melhor via para a terapia celular na colite ulcerativa foi a intravenosa e que o tratamento proposto foi eficaz no que se refere à redução da inflamação do cólon. / Mesenchymal stem cell (MSC) therapy is an alternative for the treatment of inflammatory bowel disease (IBD). Currently, therapeutic methods consist primarily on the use of drugs which aim to produce and maintain state of ulcerative colitis remission and often present side effects. Considering the ability to modulate the immune system cells and regenerate injuried tissues, MSCs can be considered an alternative for treating IBD, such as ulcerative colitis. Moreover, there is many research investigating the homing of exogenous MSCs infused through different routes in response to an inflammatory insult, and has demonstrated the migration capacity of these cells into the affected tissues. The first stage of this study consisted in the characterization and development of acute animal model of ulcerative. For this, different molecular weights and concentrations of Dextran Sulfate Sodium (DSS) reagent were tested in order to verify the best method for disease induction. After determining the appropriate animal model, that uses 2% DSS (36000-50000 Da), the cell therapy experiment was initiated. In an attempt to understand how MSCs can influence intestinal inflammation, the study evaluated the effect of MSCs transplantation using two different infusion routes, intraperitoneal and intravenous, in an acute colitis murine model. The following parameters were evaluated: clinical disease activity, colon macroscopic and histological analysis, serum inflammatory cytokine, determination apoptosis rates and oxidative stress parameters. Results show that MSC intravenous transplantation has improved the clinical severity of colitis, such as weight loss, diarrhea, and blood stool. Histological evaluation demonstrated a decreased colonic inflammation by reducing colonic crypt loss and infiltration of inflammatory cells. Also, MSCs secreted factors which seem to reduce levels of IL-6 and increase levels of IL-10 and IL-4 in the serum. In addition, an increase of apoptotic cells was observed in animals treated with intravenous MSCs, suggesting that MSCs induce cell death in T cells resistant to apoptosis. Furthermore, intravenous therapy was able to increase the levels of reduced glutathione, an important natural antioxidant, reversing the damage caused by oxidative stress in the colon. Taken together, our results demonstrate that the best route for cell therapy in ulcerative colitis was intravenous and the proposed treatment was effective with regards to reducing colon inflammation.

A cirurgia endoscópica transluminal por orifícios naturais (NOTES) é uma nova modalidade cirúrgica caracterizada pela ausência de incisões cutâneas. Diferentes vias de acesso para a NOTES já foram testadas, porém, existem poucos estudos sobre os efeitos imunomoduladores da via transretal e de sua associação com as células-tronco mesenquimais (MSCs) como adjuvante nos efeitos anti-inflamatórios e na cicatrização retal. Este trabalho objetivou avaliar a exequibilidade da técnica NOTES transretal, os efeitos imunomodulatórios e regenerativos desta abordagem cirúrgica e sua associação com as MSCs em um modelo experimental suíno. A tese foi divida em quatro capítulos sendo que o primeiro trata de uma revisão bibliográfica sobre as vias de acesso para a NOTES e suas implicações. O segundo objetivou testar a exequibilidade da via transretal em três suínos, o que demonstrou ser um acesso alternativo para procedimentos abdominais. O terceiro capítulo avalia a resposta inflamatória da técnica NOTES e da sua associação com MSC derivadas de tecido adiposo. Para isso, 11 suínos foram submetidos a NOTES transretal e distribuídos aleatoriamente em dois grupos: GNOTES e GNOTES+MSC. Amostras de sangue foram coletadas em diferentes tempos para exames de hemograma, albumina, proteína C reativa (PCR) e interleucina- 6 (IL-6). Não houveram alterações entre os grupos quanto aos valores de hemograma, albumina e PCR, sendo que a IL-6 foi indetectável em todos os animais. Histologicamente, foi observado menor quantidade de células inflamatórias no GNOTES+MSC na camada muscular. Estes dados sugerem que tanto a técnica NOTES quanto as MSCs atenuam os efeitos inflamatórios do procedimento. Um prolapso retal ocorrido como complicação da técnica NOTES transretal foi detalhadamente descrito no quarto capítulo. Assim, a técnica NOTES associada ou não às MSCs no sítio da incisão apresenta mínima resposta inflamatória em suínos submetidos à peritoneoscopia transretal. / Natural orifice transluminal endoscopic surgery (NOTES) is an evolving surgical approach to be performed without skin incisions. Different access sites have been tested, however, studies regarding immunomodulation of the transrectal approach and its association with mesenchymal stem cells (MSC) are still lacking. The viability of transrectal NOTES and the associated effects of MSC local therapy on rectal healing and inflammation were tested in a porcine model. The results of the study are depicted in fours chapters. The first chapter presents a literature review and state-of-the-art on the accesses for NOTES. The subsequent paper describes the transrectal approach performed in three pigs and its viability as an alternative access to abdominal endoscopic procedures. In the third chapter, the evaluation of the inflammatory response with transrectal NOTES and adipose tissue MSC therapy is presented. For that, 11 pigs were either submitted to NOTES only or NOTES with local MSC application. Blood samples, peritoneal fluid, and post-mortem rectal tissue specimens were collected. Total blood count, albumin and C-reactive protein showed no significant differences between groups. Interleukin-6 was undetectable in both groups. Histological evaluations demonstrated less inflammatory cells in the muscular layer of rectum of the animals where NOTES was associated with MSC. A possible lessening of the immune response may be seen with NOTES with or without MSCs; however, the presence of MSC attenuate the local inflammatory reaction in the muscular layer of porcine rectum after transrectal NOTES. A rectal prolapse that occurred after transrectal NOTES in one pig is reported in the last chapter. The transrectal NOTES technique with or without the MSCs at the incision site shows minimal inflammatory response in porcine.

Les lésions du système nerveux central (SNC) entraînent une perte neuronale associée à des déficits fonctionnels importants. En réponse à une lésion, les capacités de repousse axonale et de régénération spontanée des neurones du SNC sont limitées. Nous avons évalué, dans un modèle de lésion corticale chez la souris adulte, le potentiel des greffes de neurones corticaux embryonnaires à réparer les voies corticales lésées. L'efficacité de cette approche thérapeutique dépend (1) du degré de survie des cellules greffées, (2) de la capacité des cellules greffées à se différencier en type neuronal approprié et (3) de la capacité des neurones greffés à restaurer les voies corticales endommagées de façon spécifiques. Nous avons montré que les neurones embryonnaires corticaux d'origine du cortex moteur transplantés immédiatement après la lésion du cortex moteur adulte se différencient en neurones matures exprimant les mêmes neurotransmetteurs et marqueurs de couches corticales que ceux du cortex normal. De plus, les neurones transplantés développent des projections vers les cibles corticales et sous corticales appropriées. Par ailleurs, nous avons étudié l'influence de la neuroinflammation post-lésionnelle sur la survie des neurones transplantés et, l'influence des neurones transplantés sur la neuroinflammation de l'hôte. / Central nervous system (CNS) lesions leads to a neuronal loss associated with significant functional deficits. In response to injury, the capacity of spontaneous axonal regrowth and regeneration of neurons in the CNS are limited. We evaluated in a model of cortical lesion in adult mice, the potential of embryonic cortical neurons grafts to repair the injured cortical pathways. The efficacy of this therapeutic approach depends on (1) the degree of survival of transplanted cells, (2) the ability of the grafted cells to differentiate into neuronal appropriate type and (3) the ability of the transplanted neurons to restore damaged cortical pathways. We have shown that embryonic cortical neurons transplanted immediately after the injury of the adult motor cortex differentiate into mature neurons expressing the same neurotransmitters and markers of cortical layers that are normally expressed by intact cortex. Furthermore, the transplanted neurons develop projections to the appropriate cortical and sub-cortical targets. Furthermore, we studied the influence of post-traumatic neuroinflammation on the survival of transplanted neurons and the influence of transplanted neurons on host neuroinflammation.

L’infarctus du myocarde est une cause majeure de morbidité et mortalité adulte dans les pays développés. Le manque de perfusion myocardique induit la mort des cardiomyocytes notamment par apoptose. Un remodelage moléculaire et cellulaire s’ensuit et comprend une hypertrophie des cardiomyocytes dans la zone péri-infarcie, de la fibrose, une réactivation des gènes fœtaux et des changements métaboliques. Ce remodelage entraîne à terme une diminution de fonction menant à la défaillance cardiaque. Les traitement médicamenteux améliorent la qualité de vie et la survie mais ne peuvent guérir. La thérapie hybride (cellulaire et génique) est une approche thérapeutique nouvelle et prometteuse pour l’infarctus du myocarde. C’est dans ce contexte que s’inscrivent les travaux de ma thèse. <p>Les cellules souches mésenchymateuses (CSM) sont des cellules souches adultes de choix pour la thérapie cellulaire. Plusieurs études ont montré qu’elles participent à la cardioprotection et à la régénération du myocarde en sécrétant une myriade de facteurs de croissance et de cytokines aux effets pro-angiogéniques et anti-apoptotiques.<p>Le « stromal-derived factor-1 » (SDF-1) ou CXCL12 est une chimiokine produite par un grand nombre de cellules dont les CSM et les cardiomyocytes. Il est un ligand pour CXCR4 et CXCR7, 2 récepteurs de la famille des récepteurs liés aux protéines G. CXCL12a est un facteur critique pour la migration, la domiciliation et la survie des cellules souches de la moelle osseuse dans le myocarde infarci et pour la survie des cardiomyocytes. Dans l’infarctus aigu du myocarde, un délai entre la fenêtre temporelle d’activation du ligand et de son récepteur rend cet axe peu efficace. Dans les pathologies ischémiques chroniques, une altération de la signalisation CXCL12a/CXCR4 réduit ses effets bénéfiques.<p>Ces observations ont conduit au développement d’approches thérapeutiques ciblant l'axe CXCL12a/CXCR4. CXCL12a peut être administré seul, sa production peut être stimulée par la transplantation de cellules souches, enfin sa synthèse peut être augmentée dans le myocarde par thérapie génique ou par l’association d’une thérapie cellulaire et génique. La majorité des études montrent une amélioration du remodelage et de la fonction cardiaque associée essentiellement à une néovascularisation et un effet antiapoptotique. Cependant, les effets directs de CXCL12a sur les cardiomyocytes ne sont pas encore complètement élucidés.<p>L’objectif général de ce travail était de contribuer à la compréhension des mécanismes d’action de CXCL12a sur les cardiomyocytes néonataux de rat que celui-ci agisse seul ou dans le cadre d’une thérapie hybride.<p>Dans la première partie de ce travail, nous avons étudié les effets non génomiques de CXCL12a en nous focalisant sur l’homéostasie calcique et ses conséquences fonctionnelles. Nous avons investigué la modulation des flux calciques par CXCL12a en chargeant le cytoplasme de cardiomyocytes néonataux de rat en culture avec le Fluo-4 acétoxyméthyl ester, indicateur fluorescent du niveau de calcium. CXCL12a augmente le calcium intracytoplasmique. La réponse calcique dépend de la liaison de CXCL12a à CXCR4 et majoritairement de l’ouverture des canaux calciques dépendants de l’inositol triphosphate (IP3Rs). Le flux calcique induit par la caféine (un agoniste des récepteurs à ryanodine) est diminué lorsque les IP3Rs sont bloqués. Ceci peut s’expliquer par une interaction entre ces 2 canaux. L’incubation avec le CXCL12a augmente in vitro la fréquence de battement des cardiomyocytes et cet effet est additif à celui de la forskoline (un activateur de l’adénylate cyclase). In vivo, l’administration intramyocardique de CXCL12a augmente le dP/dt max (indice de contractilité cardiaque) du ventricule gauche. <p>Dans la deuxième partie de ce travail, nous avons étudié les effets génomiques de CXCL12a; le but de cette étude était double :(1) identifier de nouvelles voies de signalisation contribuant aux effets de CXCL12a sur les cardiomyocytes et (2) comparer les effets de CXCL12a administré seul aux effets du surnageant de CSM surexprimant CXCL12a. Nous avons construit le lentivirus pWXLd-CXCL12a-IRES-GFP pour transduire des CSM en culture. L’expression protéique de CXCL12a dans le surnageant des CSM transduites a été confirmée par ELISA et l’activité du CXCL12a a été vérifiée par le test à l’aequorine. Pour identifier de nouvelles voies de signalisation modulées à l’étage transcriptionnel, nous avons privilégié le microarray, méthodologie qui permet une approche globale sans à priori. Nous avons ensuite confirmé les résultats par une approche ciblée sur certains gènes par la technique de RTQ-PCR. Pour le microarray, les cardiomyocytes ont été incubés pendant 1 heure avec (a) du CXCL12a commercial &61480;&61493;µ&61517;&61481; dilué dans le milieu des cardiomyocytes sans FBS, (b) le milieu des cardiomyocytes sans FBS (échantillon témoin de a), (c) le surnageant de CSM transduites par le virus pWXLd-CXCL12a-IRES-GFP et (d) le surnageant de CSM transduites par le virus pWXLd-GFP (échantillon témoin de c). Un ensemble discret de 218 gènes correspondant à 0,63% du génome du rat étaient régulés. Parmi les 60 gènes communs rapidement modulés dans les deux conditions (a et c), 34 étaient sur-exprimés alors que 26 étaient sous-exprimés. L’analyse avec le logiciel David suggère que le CXCL12a seul à la dose de 5 μM ou présent dans le surnageant de CSM le surexprimant à la concentration d’environ 2 nM module des voies déjà connues comme la voie des MAPkinases et plusieurs voies liées à l’apoptose comme JAK/STAT, p53 et NOD ainsi que 2 nouvelles voies: le voie des adipocytokines et de PPAR. Par RTQ-PCR, nous avons confirmé la modulation positive par CXCL12a de JAK2 et AKT. De plus, CXCL12a réprime l’expression protéique de la LPL, l’expression génique de la FABP et de l’Angptl-4 et l’expression génique et protéique de l’adiponectine, protéines toutes impliquées dans le transfert des acides gras et leur β oxydation. <p>Nous avons ensuite investigué les effets génomiques de CXCL12a dans le cadre d’une thérapie hybride. L’analyse du microarray et l’analyse ciblée de quelques gènes ont permis de conclure que la modulation de l’expression génique dépend non seulement de la concentration en CXCL12a mais également de la présence d’autres facteurs soit issus directement du milieu de culture commercial des CSM soit issus du milieu conditionné des CSM.<p>Ce travail ouvre de nouvelles perspectives pour mieux comprendre le rôle de CXCL12a dans l’homéostasie calcique et le métabolisme des lipides et son impact dans la physiopathologie du cœur. De plus, ce travail appuie le fait que le développement clinique des thérapies hybrides doit être précédé d’une investigation complète des effets génomique et non génomiques de cette thérapie sur les cardiomyocytes. Cependant, il faut rester prudent car, à cause de l’environnement du myocarde sain ou malade, aucune étude fondamentale ne permet de prédire l’ensemble des effets in vivo.<p> / Doctorat en Sciences biomédicales et pharmaceutiques / info:eu-repo/semantics/nonPublished