Topologieoptimierte Geometrie wird vom Konstrukteur in einem Format benötigt, das im CAD verwendet werden kann. Die Herausforderung ist, dass man als Optimierungsergebnis eine STL-Geometrie bekommt, doch fürs CAD soll die Oberfläche möglichst glatt und vereinfacht sein. Die Software MSC Apex erzeugt aus einer STL-Geometrie eine echte, geglättete Parasolid-Geometrie. Eine spezielle Form der Topologieoptimierung ist die Topometrieoptimierung, welche die Rippenstruktur auf einem Blech vorschlägt. Auch hierfür ist Geometrierückführung möglich. Auch stark verformte Bauteile, z.B. Gummiteile, kann man als Geometrie im verformten Zustand ans CAD zurückgeben, um zu sehen, wie sie dann in die Baugruppe passen. / Topology optimized geometry must be provided to the designer in a format that can be used in CAD. The challenge is that the optimization result is typically an STL geometry, but for CAD the surface should be as smooth and simplified as possible. The MSC Apex software creates a real, smoothed parasolid geometry from an STL geometry. A special form of topology optimization is topometry optimization, which suggests the rib structure on a sheet. Reverse engineering is also possible for this. Even heavily deformed components, e.g. rubber parts, can be returned to CAD as geometry in the deformed state, to see how they fit into the assembly in this state.

The solid-state dye sensitized solar cell (SDSC) is an emerging photovoltaic technology which promises inexpensive materials, roll-to-roll processing, and a stable architecture. In this thesis, I seek to enhance electronic transport in order to enable thicker devices and yield higher power conversion efficiencies. I adopt a multipronged approach to advance three aims, employing analytical, computational, and experimental methodologies. First, I generalize existing models of the dye sensitized solar cell (DSSC) to allow simple parameter fitting of real devices and to account for previously ignored electronic processes. In Chapter 3 and Chapter 4 I present a nondimensional model capable of fitting real devices and simulating transient behavior without extensive material knowledge. Subsequently in Chapter 5, I introduce a novel three-dimensional model which incorporates electronic drift. Second, in Chapter 4 I critically assess a widespread method of measuring the charge collection efficiency, the summary metric that describes the efficacy of charge transport in the SDSC. I discover that the conventional method is inaccurate for values of the collection efficiency below 90% because of large experimental error and an intrinsic inaccuracy in applying a transient method to measure a steady-state parameter. Third, I aim to increase the rate of charge transport by employing new materials and nanostructures in the place of conventional nanocrystalline TiO2. In Chapter 5, I present evidence of faster transport and enhanced efficiency in flexible SnO2 nanowire SDSCs, ZnO nanowire SDSCs, and the first viable SnO2/P3HT SDSC, where photoanode and hole transporter have been replaced with higher mobility materials. Finally, in Chapter 6, I investigate use of TiO2 mesoporous single crystals (MSCs) with high surface area and extended crystallinity. After demonstrating the viability of MSCs in SDSCs, I examine enhanced transport caused by the background doping effect of thermal treatment. Together, the progress achieved toward diverse and ambitious goals advances the field and delineates routes to future progress for SDSC development.

The biggest shift in the automotive industry lies ahead. Autonomous vehicles create both curiosity and skepticism among drivers and people around. Autonomous vehicles, more specifically trucks, will not be utterly self-driving overnight. The whole transformation will take place in different phases. When a vehicle does not need a driver behind the wheel, new needs will arise. This is where this project comes into play. On behalf of Scania, a new driver’s seat shall be developed for new needs from the drivers for autonomous trucks of type 4. The project was carried out at Scania’s design department for cabin interiors. The project aimed to develop new needs for the future autonomous level 4 trucks in order to develop a driver’s seat that meets these needs. The project began with a planning phase in which the goals and the time frame for the project were set up. The project was then implemented in four different phases inspired by CDIO (n.d.). The work began with a benchmarking on existing trucks and passenger cars, but also on the future visions of different competitors regarding autonomous vehicles. Much work was put into understanding theories and interpreting relevant information. The users were used early in the project in the form of interviews, observations, and a survey that reached 299 truck drivers. The work then continued with various forms of brainstorming both within the project group and together with engineers from the group at Scania. The final work contained a CAD model of both prototype, CAID models of the final design, and a prototype scale of 1:1. The final result of the project is a new driver’s seat with the possibility of pushing the seat almost three times further back than the current seat. It can now be done when the driver’s seat is part of the bed. During the user study and the brainstorming, new needs were taken from the perspective of the sun being able to adapt to three different positions; rest, drive, work. The new driver’s seat now gives the drivers this opportunity. The result of this project may be more effective in driving the driver, which benefits both Scania and the customers in the form of the drivers being able to drive longer than previously allowed. / Det största skiften inom fordonsbranschen ligger framför oss. Autonoma fordon skapar både nyfikenhet och en skepsis bland förare och människor runt omkring. Autonoma fordon, mer specifikt lastbilar, kommer inte bli helt självkörande under en natt. Hela för- vandlingen kommer ske i olika faser. När ett fordon inte behöver en förare bakom ratten kommer nya behov uppkomma. Det är här det här projektet kommer in i bilden. På uppdrag av Scania, ska en ny förarstol utvecklas för nya behov från förarna för autonoma lastbilar av typen nivå 4. Projektet är ett examensarbete gjort av två studenter vid utbildningen civilingenjör inom teknisk design med inriktning produktutveckling, vid Luleå tekniska universitet. Projektet genomfördes på Scanias konstruktionsavdelning för hyttint- eriör. Målet för projektet var att ta fram nya behov för framtidens autonoma nivå 4 lastbilar för att sedan utveckla en förarstol som uppfyller dessa behov. Projektet började med en planeringsfas där målen och tidsramen för projektet sattes upp. Projektet genomfördes sedan i fyra olika faser inspirerade av CDIO (n.d.). Arbetet började med att en benchmarking gjordes på befintliga lastbilar och personbilar men även på olika konkurrenters framtidsvisioner gällande autonoma fordon. Mycket arbete lades på att förstå teorier och tolka relevant infor- mation. Användarna användes tidigt i projektet i form av intervjuer, observationer och en enkät som nådde ut till 299 lastbilsförare. Arbetet fortsatte sedan med olika former av brainstorming både inom projektgruppen och tillsammans med ingenjörer från gruppen på Scania. Slutgiltiga arbetet innehöll CAD-modeller av både prototyp, CAID-modeller av slutgiltig design samt en prototyp i skala 1:1. Det slutgiltiga resultatet av projektet är en ny förarstol med möjligheten att skjuta bak stolen nästan tre gånger längre än vad som tidigare var möjligt. Det kan nu göras då förarstolen är en del av sängen. Under användarstudien och brainstormingen togs nya behov fram i from av att solen ska ha möjlighet att anpassas till tre olika lägen; vila, köra, arbeta. Den nya förarstolen ger nu förarna den här möjligheten. Resultatet av det här projektet kan komma att effektivisera föraryrket, vilket gynnar både Scania och kunderna i form av att förarna kommer kunna köra längre än vad tidigare varit tillåtet.

A Doença Pulmonar Obstrutiva Crônica (DPOC) é caracterizada pela limitação persistente de trocas gasosas, usualmente progressiva e associada a uma resposta inflamatória crônica exacerbada das vias aéreas a partículas e gases nocivos. Apesar de prevenível e tratável, não se logrou até o presente uma terapêutica eficaz, que resulte na cura da doença. Neste cenário, a terapia celular apresenta-se como uma alternativa terapêutica potencialmente promissora em DPOC, bem como em outras doenças pulmonares degenerativas e de caráter inflamatório. Porém, vários aspectos da terapia celular carecem de um melhor entendimento. Um dos principais desafios ao sucesso da terapia celular são as baixas taxas de sobrevivência das células transplantadas. O Inibidor do Ativador de Plasminogênio 1 (Plasminogen Activator Inhibitor 1 - PAI-1) pode representar um potencial mediador da sobrevivência de células estromais mesenquimais (CTM) pós-transplante, pois tem sido proposto que anticorpos neutralizadores do PAI-1 auxiliam no aumento da sobrevivência de CTM no tecido-alvo da terapia celular. Desta forma, a diminuição dos níveis de PAI-1 possui um potencial terapêutico interessante, ao modular os principais processos envolvidos na criação de um ambiente pouco propício ao \"homing\" celular durante o processo de injúria. A diminuição dos níveis de PAI-1 é promovida, pela sinvastatina, fármaco da família das estatinas. Desta forma, objetivou-se com este trabalho analisar os efeitos da sinvastatina sobre a expressão do PAI-1, bem como sua influência na sobrevivência das células infundidas para terapia celular de enfisema pulmonar em modelo murino. Camundongos da linhagem FVB foram submetidos à instilação intranasal de elastase para indução de enfisema pulmonar e, posteriormente, tratados com CTM do tecido adiposo e sinvastatina. Os resultados mostraram que, quanto aos aspectos morfológicos e funcionais, considerando-se a análise conjunta de ambos os pulmões, não houve diferença estatisticamente significativa entre os grupos submetidos à instilação intranasal de elastase e submetidos à terapia celular com CTM tratados ou não com sinvastatina. Quando porém os pulmões foram analisados individualmente constatou-se que não houve diferença estatisticamente significativa entre os grupos controle e os resultados referentes ao lado direito do pulmão dos animais tratados com elastase e que receberam sinvastatina e infusão de CTM. Diferenças anatômicas entre os lados direito e esquerdo do pulmão, levaram a uma maior deposição de células no lado direito, como evidenciado pelos resultados obtidos nos ensaios de bioluminescência. Pode-se, portanto, inferir que a recuperação morfológica no lado direito do pulmão de animais com DPOC/enfisema poderia ser decorrente de um efeito regenerativo parácrino das CTM associadas à sinvastatina. / Chronic Obstructive Pulmonary Disease - COPD is characterized by the persistent limitation of gas exchange, is usually progressive, and associated to a chronic augmented inflammatory response of the airways to particles and noxious gases. Despite preventable e treatable, an effective, curative therapeutic approach is yet to be achieved. In this context, cell therapy presents itself as a promising therapeutic approach for COPD and other pulmonary inflammatory and degenerative diseases. However, many aspects of cell therapy with stem cells remain unclear. One of the major challenges to the success of cell therapy are the low survival rates of transplanted cells. The Plasminogen Activator Inhibitor 1 (PAI-1) is a potential mediator of the survival of mesenchymal stromal cells (MSC) after transplantation, since PAI-1 neutralizing antibodies have been shown to increase the survival rate of MSC in the target tissue of cell therapy. Thus, the decreased levels of PAI-1 has an interesting therapeutic potential to modulate key processes involved in creating an inhospitable environment, during the process of injury, to the homing of transplanted cells. Decreased levels of PAI-1 are promoted by simvastatin, a drug of the statins family. Thus, the goal of this work was to evaluate the effect of simvastatin in vivo on the expression of PAI-1, as well as its influence on the survival rate of infused cells in mice model of cell therapy for pulmonary COPD/emphysema. FVB mice were submitted pulmonary emphysema induction by means of intranasal instillation of elastase and than treated with adipose-derived mesenchymal stem cells and simvastatin. The results regarding morphological and functional aspects, when considering the analisys of both lungs, presented no statistically significant difference among the groups submitted to intranasal instillation of elastase and cell therapy with MSC, treated or not with simvastatin. However, when the lungs where analyzed individually, it was found that there was no statistically significant difference between the control group and the results regarding the right lung of animals treated with elastase and that received simvastatin and MSC infusion. Anatomical differences between the right and left sides of the lung lead to a higher deposition of cells in the right side, as observed in the bioluminescence assays. Thus, it is possible to infer that the morphological recovery in the right side of the lung of animals with DPOC/emphysema could be due to a regenerative paracrine effect of mesenchymal stem cells associated with simvastatin.

Mesenchymal stem cells (MSCs) may benefit vascular cell-based therapies as smooth muscle or endothelial cell substitutes or through paracrine actions to repair, replace, or regenerate vascular tissue. Previous studies have demonstrated that MSCs can adopt traits of smooth muscle cells (SMCs) or endothelial cells (ECs), as well as secrete specific factors that tune signaling and material properties in the local environment. Few studies have investigated the cell signaling response of MSCs to mechanical forces present in the vasculature: specifically, shear stress due to blood flow and cyclic strain due to pulsatile blood flow. Thus, the central objective of this dissertation was to determine the signaling responses of MSCs to vascular-relevant applied physical forces, in comparison with that of differentiated vascular cells. Vascular-relevant mechanosignaling of MSCs was assessed through two comparisons: (1) MSC and SMC responses to applied cyclic strain and (2) MSC and EC responses to applied fluid shear stress. MSCs and SMCs were seeded on fibronectin-coated silicone and subjected in vitro to cyclic strain (10%, 1 Hz) or parallel static culture using a custom-built equibiaxial cyclic strain device. Gene expression analysis of 84 signal transduction molecules demonstrated both cell types respond with significant (p<0.05, n=3) fold-changes (|FC|≥ 1.5) within 24 hours of applied equibiaxial strain. Most strain-responsive genes identified were significantly strain-responsive in only one cell type. A signaling trio of Interleukin 8, Vascular cell adhesion molecule 1, and Heme oxygenase 1 was significantly altered in both MSCs and SMCs, suggesting cyclic strain regulates immune and inflammatory functions in both cell types. The response to shear stress of MSCs and ECs was compared using cells seeded on type I collagen or fibronectin and exposed to steady laminar shear stress (5 or 15 dyn/sq-cm) using a parallel plate shear chamber system. Gene expression was compared in MSCs and ECs for a panel of immune and inflammation-related markers. Expression of Cox-2 and Hmox-1 increased significantly (p<0.05, n≥3; |FC|≥1:5) in both cell types. Reduced shear stress-responses of Mcp-1, Pecam-1, and VE-Cad in MSCs relative to ECs suggests that MSCs promote less inflammation and immune activation in response to shear stress than ECs. Mechanosensitivity profiles for MSCs and differentiated vascular cells were broadened using whole genome microarrays. These high-throughput studies confirmed that (1) signaling profiles between sample groups vary significantly more (p<0.05, n=3) with cell type than applied force condition and (2) a subset of conserved mechanosensitive genes alter expression levels significantly and in the same direction fold-change in multiple cell types. Bioinformatics analysis of these conserved mechanoresponsive genes highlighted oxidative stress, cell cycle, and DNA replication as functions regulated by vascular-relevant mechanical cues. These studies demonstrate that MSCs partially reproduce differentiated vascular cell mechanosignaling, while simultaneously altering expression of genes not typically force-responsive in vascular cells. This work defines a role for conserved mechanosignals, based on genes whose expression in response to applied force alters significantly (p<0.05, n≥3) and by at least 1.5-fold change in multiple cell types and/or force types. Comparisons completed for this dissertation motivate future studies to track the functional impact of specific similar or unique MSC mechanoresponses. This work contributes to design of MSC-based vascular therapies and an understanding of stem and differentiated cell mechanobiology.

This thesis is concerned with recursive partitioning of models of a generalized linear model type (GLM-type), i.e., maximum likelihood models with a linear predictor for the linked mean, a topic that has received constant interest over the last twenty years. The resulting tree (a ''model tree'') can be seen as an extension of classic trees, to allow for a GLM-type model in the partitions. In this work, the focus lies on applied and computational aspects of model trees with GLM-type node models to work out different areas where application of the combination of parametric models and trees will be beneficial and to build a computational scaffold for future application of model trees. In the first part, model trees are defined and some algorithms for fitting model trees with GLM-type node model are reviewed and compared in terms of their properties of tree induction and node model fitting. Additionally, the design of a particularly versatile algorithm, the MOB algorithm (Zeileis et al. 2008) in R is described and an in-depth discussion of how the functionality offered can be extended to various GLM-type models is provided. This is highlighted by an example of using partitioned negative binomial models for investigating the effect of health care incentives. Part 2 consists of three research articles where model trees are applied to different problems that frequently occur in the social sciences. The first uses trees with GLM-type node models and applies it to a data set of voters, who show a non-monotone relationship between the frequency of attending past elections and the turnout in 2004. Three different type of model tree algorithms are used to investigate this phenomenon and for two the resulting trees can explain the counter-intuitive finding. Here model tress are used to learn a nonlinear relationship between a target model and a big number of candidate variables to provide more insight into a data set. A second application area is also discussed, namely using model trees to detect ill-fitting subsets in the data. The second article uses model trees to model the number of fatalities in Afghanistan war, based on the WikiLeaks Afghanistan war diary. Data pre-processing with a topic model generates predictors that are used as explanatory variables in a model tree for overdispersed count data. Here the combination of model trees and topic models allows to flexibly analyse database data, frequently encountered in data journalism, and provides a coherent description of fatalities in the Afghanistan war. The third paper uses a new framework built around model trees to approach the classic problem of segmentation, frequently encountered in marketing and management science. Here, the framework is used for segmentation of a sample of the US electorate for identifying likely and unlikely voters. It is shown that the framework's model trees enable accurate identification which in turn allows efficient targeted mobilisation of eligible voters. (author's abstract)

The first definitive haematopoietic stem cells (HSCs) produced during embryonic development are generated from a specialised subset of endothelial cells known as haemogenic endothelium. Recently, it was reported that Gata3 plays a dual role in the development of sympathetic nervous system and haematopoietic system. In fact, Gata3 has proven to be crucial for the production of HSCs through regulation of catecholamine production from the co-developing sympathetic nervous system. Also, it was recently shown that Gata3 is expressed in the haemogenic endothelium and haematopoietic progenitor cells. Here, I will specifically examine the role of Gata3 in the production of HSCs; if it is expressed and plays a role in the precursors from which HSCs arise. Using a Gata3-GFP reporter mouse line, we found that Gata3 is expressed in various cell types in the HSCs microenvironment, including mesenchymal cells, endothelial cells, haematopoietic cells and sympathetic nervous system, and this expression was stage dependant. In the endothelial cells, we have found that the haemogenic endothelium activity is enriched in Gata3 expressing cells. Within the haematopoietic cells, we have found that Gata3 marks a specific stage along the developmental pathway towards the generation of definitive haematopoietic stem cells, and that Gata3 expressing haematopoietic cells are enriched for the most immature and stem cell like progenitors. Moreover, Gata3 will be specifically knocked out in haemogenic endothelial cells to determine whether it plays an essential role in the production of HSCs from the endothelium using the Vec-Cre system. We found that Gata3 within the haemogenic endothelium plays a major role in haematopoietic progenitors formation, and possibly haematopoietic stem cell formation. Finally, we used molecular assay (RNA seq) to identify the role of Gata3 in the haematopoietic stem cell microenvironment and found that Gata3 plays a major role in the development and differentiation of various cells and systems, and implicated Gata3 as cell cycle regulator. In summary, we found that Gata3 expressing cells is enriched for haemogenic endothelium, crucial for the haematopoietic progenitors formation, plays and important role in endothelial to haematopoietic transition, and plays a key developmental role in both haematopoietic stem cell and its microenvironment.

The present paper is a study of modied Hermite polynomials of two variables Hn(x; y; a) which for a = e reduces to Hermite polynomials of two variables Hn(x; y) due to M.A. Khan and G.S. Abukhammash. / El presente artculo se estudian polinomios modicados de Hermite de dos variables Hn(x; y; a) que para a = e se reducen a los polinomios de Hermite de dos variables Hn(x; y) introducidos por M.A. Khan y G.S.Abukhammash.

A Doença Pulmonar Obstrutiva Crônica (DPOC) é caracterizada pela limitação persistente de trocas gasosas, usualmente progressiva e associada a uma resposta inflamatória crônica exacerbada das vias aéreas a partículas e gases nocivos. Apesar de prevenível e tratável, não se logrou até o presente uma terapêutica eficaz, que resulte na cura da doença. Neste cenário, a terapia celular apresenta-se como uma alternativa terapêutica potencialmente promissora em DPOC, bem como em outras doenças pulmonares degenerativas e de caráter inflamatório. Porém, vários aspectos da terapia celular carecem de um melhor entendimento. Um dos principais desafios ao sucesso da terapia celular são as baixas taxas de sobrevivência das células transplantadas. O Inibidor do Ativador de Plasminogênio 1 (Plasminogen Activator Inhibitor 1 - PAI-1) pode representar um potencial mediador da sobrevivência de células estromais mesenquimais (CTM) pós-transplante, pois tem sido proposto que anticorpos neutralizadores do PAI-1 auxiliam no aumento da sobrevivência de CTM no tecido-alvo da terapia celular. Desta forma, a diminuição dos níveis de PAI-1 possui um potencial terapêutico interessante, ao modular os principais processos envolvidos na criação de um ambiente pouco propício ao \"homing\" celular durante o processo de injúria. A diminuição dos níveis de PAI-1 é promovida, pela sinvastatina, fármaco da família das estatinas. Desta forma, objetivou-se com este trabalho analisar os efeitos da sinvastatina sobre a expressão do PAI-1, bem como sua influência na sobrevivência das células infundidas para terapia celular de enfisema pulmonar em modelo murino. Camundongos da linhagem FVB foram submetidos à instilação intranasal de elastase para indução de enfisema pulmonar e, posteriormente, tratados com CTM do tecido adiposo e sinvastatina. Os resultados mostraram que, quanto aos aspectos morfológicos e funcionais, considerando-se a análise conjunta de ambos os pulmões, não houve diferença estatisticamente significativa entre os grupos submetidos à instilação intranasal de elastase e submetidos à terapia celular com CTM tratados ou não com sinvastatina. Quando porém os pulmões foram analisados individualmente constatou-se que não houve diferença estatisticamente significativa entre os grupos controle e os resultados referentes ao lado direito do pulmão dos animais tratados com elastase e que receberam sinvastatina e infusão de CTM. Diferenças anatômicas entre os lados direito e esquerdo do pulmão, levaram a uma maior deposição de células no lado direito, como evidenciado pelos resultados obtidos nos ensaios de bioluminescência. Pode-se, portanto, inferir que a recuperação morfológica no lado direito do pulmão de animais com DPOC/enfisema poderia ser decorrente de um efeito regenerativo parácrino das CTM associadas à sinvastatina. / Chronic Obstructive Pulmonary Disease - COPD is characterized by the persistent limitation of gas exchange, is usually progressive, and associated to a chronic augmented inflammatory response of the airways to particles and noxious gases. Despite preventable e treatable, an effective, curative therapeutic approach is yet to be achieved. In this context, cell therapy presents itself as a promising therapeutic approach for COPD and other pulmonary inflammatory and degenerative diseases. However, many aspects of cell therapy with stem cells remain unclear. One of the major challenges to the success of cell therapy are the low survival rates of transplanted cells. The Plasminogen Activator Inhibitor 1 (PAI-1) is a potential mediator of the survival of mesenchymal stromal cells (MSC) after transplantation, since PAI-1 neutralizing antibodies have been shown to increase the survival rate of MSC in the target tissue of cell therapy. Thus, the decreased levels of PAI-1 has an interesting therapeutic potential to modulate key processes involved in creating an inhospitable environment, during the process of injury, to the homing of transplanted cells. Decreased levels of PAI-1 are promoted by simvastatin, a drug of the statins family. Thus, the goal of this work was to evaluate the effect of simvastatin in vivo on the expression of PAI-1, as well as its influence on the survival rate of infused cells in mice model of cell therapy for pulmonary COPD/emphysema. FVB mice were submitted pulmonary emphysema induction by means of intranasal instillation of elastase and than treated with adipose-derived mesenchymal stem cells and simvastatin. The results regarding morphological and functional aspects, when considering the analisys of both lungs, presented no statistically significant difference among the groups submitted to intranasal instillation of elastase and cell therapy with MSC, treated or not with simvastatin. However, when the lungs where analyzed individually, it was found that there was no statistically significant difference between the control group and the results regarding the right lung of animals treated with elastase and that received simvastatin and MSC infusion. Anatomical differences between the right and left sides of the lung lead to a higher deposition of cells in the right side, as observed in the bioluminescence assays. Thus, it is possible to infer that the morphological recovery in the right side of the lung of animals with DPOC/emphysema could be due to a regenerative paracrine effect of mesenchymal stem cells associated with simvastatin.

Multipotent mesenchymal stromal cells (MSC) were first discovered in bone marrow and can be isolated from “virtually all organs”. They could participate in tissue maintenance and self-renewing process. They are able to adhere to plastic surfaces and acquire a fibroblastic shape when isolated. They are characterized by a particular phenotype and are able to differentiate into several cell types if cultivated in a specific induction medium. These characteristics were defined on MSC in culture and do not represent how they may be in situ.MSC present particular properties. They can secrete growth factors and several cytokines that give them a trophic activity on one hand and the ability to modulate the immune system on the other hand. They are also able to differentiate. These different properties make them an attractive candidate for cell therapy.MSC are already the focus of several pre-clinical and clinical studies. Nevertheless, the results of these studies are difficult to interpret due to limited understanding of their basic biology. MSC are poorly defined in situ and are heterogeneous. Their heterogeneity is dictated by their tissue of origin and cell preparation. To date, there is no standard protocol for MSC isolation and culture. This leads to numerous questions regarding patient safety, and these questions require answers.The first part of the work deals with the methods used to optimize the extraction of MSC and purification from adipose tissue, one of the main sources of autologous MSC with bone marrow. Classical methods require an enzymatic digestion step. The enzyme used and the duration of adipose tissue digestion time can induce cellular alterations and modify cell functions. Moreover, the addition of a xenobiotic increases the risk of contamination and complicates the monitoring of good manufacturing practices (GMP). We propose a method that does not require this enzymatic digestion step while being easier, safer, faster, gentler and less expensive. Compared to the classical enzymatic method, our method yields an equivalent number of MSC from adipose tissue while preserving their properties.The second part of this work focuses on the characterization of the MSC subpopulations from adipose tissue and compares them to those from bone marrow, which are the historical gold standard. The study made it possible to deepen the knowledge of MSC surface markers in situ from these 2 sources. It also evaluated the various properties of the isolated subpopulations thanks to the cell surface markers CD271, SUSD2, MSCA-1, CD44 and CD34. We showed that MSC from bone marrow express MSCA-1, CD271 and SUSD2 markers in situ. We also found that a population clearly positive for the CD34 does exist in situ with different properties compared to those of the unselected populations or the negative counterpart. 2 populations that are negative and positive for CD44 also exist with similar properties.In contrast to bone marrow MSC, only one selection was able to effectively isolate MSC from adipose tissue by a positive selection based on the expression of CD34. We also isolated a CD271+ population but only from lipoaspirate samples and not from abdominoplasty samples. Collectively, our results suggest that MSCA-1 seems to be the best marker through which to isolate MSC from bone marrow and that CD34 is the only marker able to positively isolate cells from adipose tissue. Thus, we show that the MSC from the different sources share similar properties although they have specific characteristics. The choice of the source and of the marker with which to isolate a particular subpopulation is important depending on their intended clinical use. / Les cellules stromales mésenchymateuses multipotentes (CSM) ont été mises en évidence dans la moelle osseuse et peuvent être isolées de « virtuellement tous les organes ». Elles participeraient à la maintenance et au renouvellement des tissus. Une fois isolées, elles sont capables d’adhérer à des surfaces en plastique en prenant une forme fibroblastique. Elles sont caractérisées par un phénotype particulier et peuvent se différencier en divers types cellulaires lorsque cultivées dans un milieu d’induction spécifique. Ces caractéristiques ont été définies sur les CSM en culture et ne reflètent pas forcément ce qui se passe in situ.Les CSM présentent des propriétés particulières. Elles peuvent sécréter des facteurs de croissance ainsi que de nombreuses cytokines qui leur permettent d’une part d’avoir une activité trophique et d’autre part de moduler le système immunitaire. Elles sont aussi capables de se différencier. Ces différentes propriétés les rendent particulièrement attractives pour la thérapie cellulaire.Les CSM font déjà l’objet de nombreuses études pré-cliniques et cliniques dont les résultats sont difficilement interprétables car nous n’avons à l’heure actuelle qu’une compréhension limitée de leur biologie de base. Les CSM sont encore mal définies in situ et sont hétérogènes. Cette hétérogénéité provient de leur différence d’origine et de leur préparation cellulaire :il n’existe aucune standardisation des protocoles d’isolation et de culture. Cette hétérogénéité entraine de nombreuses questions relatives à la sécurité du patient qui doivent être élucidées.La première partie de ce travail cherche à optimiser les méthodes d’extraction et de purification des CSM du tissu adipeux humain, la principale source de CSM autologues avec la moelle osseuse. Les méthodes classiques requièrent une étape de digestion enzymatique dont l’enzyme utilisée et le temps de digestion du tissu adipeux peuvent induire des altérations cellulaires et modifier leurs fonctions. De plus, l’adjonction de xénobiotiques augmente le risque de contamination et complique le suivi des bonnes pratiques de fabrication (BPF). Nous proposons une méthode qui s’affranchit de cette étape de digestion enzymatique tout en étant plus facile, plus sûre, plus rapide, moins chère et moins traumatisante pour les cellules. Elle permet d’obtenir un nombre tout aussi important de CSM du tissu adipeux que la méthode enzymatique classique en préservant leurs propriétés.La deuxième partie de ce travail vise à caractériser les sous populations de CSM du tissu adipeux humain en les comparant à celles de la moelle osseuse, source de référence historique. Cette étude a permis d’approfondir la connaissance des marqueurs de surface des CSM de ces 2 sources in situ, tout en évaluant les différentes propriétés des sous-populations isolées grâce aux marqueurs de surface CD271, SUSD2, MSCA-1, CD44 et CD34. Nous avons montré que les CSM de la moelle osseuse expriment les marqueurs MSCA-1, CD271 et SUSD2 in situ et qu’il existait une sous-population clairement positive pour le CD34 avec des propriétés différentes de celles de la population non sélectionnée ou négative pour ce marqueur. Il existe aussi 2 sous-populations positive et négative pour le CD44 avec des propriétés similaires.Contrairement aux CSM de la moelle osseuse, une seule sélection a permis d’isoler efficacement les CSM du tissu adipeux par une sélection positive sur base de l’expression du CD34. Nous avons pu aussi isoler une population CD271+ mais seulement des prélèvements de lipoaspirations et non des abdominoplasties.Au vu de nos résultats, MSCA-1 semble le meilleur marqueur pour isoler les CSM de la moelle osseuse tandis que le CD34 est le seul marqueur capable d’isoler positivement celles du tissu adipeux. Ainsi, nous montrons que les CSM issues de différentes sources partagent des propriétés similaires avec cependant des caractéristiques propres. Le choix de la source et du marqueur pour isoler une sous-population sont donc importants en fonction de leur utilité clinique envisagée. / Doctorat en Sciences biomédicales et pharmaceutiques (Médecine) / info:eu-repo/semantics/nonPublished