Bakgrund Diabetes mellitus är ett samlingsnamn för olika diabetessjukdomar, däribland typ 1 diabetes och typ 2 diabetes. Typ 1 diabetes och typ 2 diabetes är kroniska sjukdomar där insulinproduktionen helt har upphört eller inte är tillräckligt för att täcka kroppens behov. Den tekniska utvecklingen inom hälso-och sjukvård har blivit alltmer digitaliserad och skapat förutsättningar för en ny typ av stöd med mobila applikationer. Egenvård är en viktig del av diabetesbehandlingen och mobila applikationer kan vara ett hjälpmedel för personer med diabetes. Sjuksköterskans roll behöver anpassas för att möta kraven inom en mer digitaliserat hälso-och sjukvårds miljö. Avsikten var att ge patienten adekvat information och utbildning av mobila applikationer för att stärka patientens egenvårdsförmåga. Syfte Syftet är att belysa patienters upplevelser och erfarenheter av mobila applikationer som stöd för egenvård med diabetes typ 1 och typ 2. Metod Studien genomfördes som en icke-systematisk litteraturöversikt som inkluderade 14 vetenskapliga artiklar från databaserna PubMed och CINAHL. De vetenskapliga artiklarna var publicerade från de fem senaste åren och var av både kvalitativ och kvantitativ ansats. Vidare hade studien en systematisk struktur där samtliga artiklarna hade kvalitetsgranskat i enlighet med Sophiahemmets bedömningsunderlag. Resultatet erhölls genom en integrerad dataanalys. Resultat Personernas upplevelser och erfarenheter sammanställdes i tre huvudkategorier och flera underkategorier. Av de 14 utvalda artiklarna var sex kvalitativa, fem kvantitativa och tre utav en mixad metod. Resultaten visar på en övervägande positiv respons mot mobila applikationer, där de bidrar till förbättrad egenvård och engagemang. Trots detta kvarstår frågor om användarvänlighet och tekniska begränsningar. Slutsats Mobila applikationer har stor potential att förbättra diabetesvården genom att stärka patienters egenvård och erhålla viktig information om sjukdomen till vårdgivaren. Framtidens forskning bör fokusera på att förbättra design och funktionalitet samt att adressera användares frustation och stress. / Background Diabetes mellitus is an umbrella term for various diabetes diseases, including type 1 diabetes and type 2 diabetes. Type 1 and type 2 diabetes are chronic conditions where insulin production has completely ceased or is insufficient to meet the body's requirements. The technological advancements in healthcare have gradually become more digitalized and created opportunities for a new type of support through mobile applications. Self-care is a crucial component of diabetes treatment, and mobile applications can serve as a tool for patients with diabetes. The nurse’s role needs to be adapted to meet the demands of a more digitized healthcare environment. This is to provide patients with adequate information and education on mobile applications to strengthen the patient's self-care ability. Aim The purpose is to shed light on patients' experiences and perceptions of mobile applications as support for self-care in type 1 and type 2 diabetes. Method The study was conducted as a non-systematic literature review, which included 14 scientific articles retrieved from the databases PubMed and CINAHL. These articles were published within the last five years and encompassed both qualitative and quantitative approaches. Furthermore, the study followed a systematic structure where all articles were quality-assessed according to Sophiahemmet's evaluation criteria. The results were obtained through an integrated data analysis. Results The individuals' experiences and perceptions were compiled into three main categories and several subcategories. Out of the 14 selected articles, six were qualitative, five were quantitative, and three utilized a mixed methods approach. The results indicate a predominantly positive response towards mobile applications, as they contribute to improved self-care and engagement. However, questions regarding usability and technical limitations remain. Conclusions Mobile applications have significant potential to enhance diabetes care by empowering patients in self-management and providing important disease-related information to healthcare providers. Future research should focus on improving design and functionality, as well as addressing users' concerns regarding frustration and stress.

Background and aims: Type 2 Diabetes Mellitus (T2DM) presents a significant global health challenge, characterized by impaired insulin secretion and/or action. A critical aspect of managing T2DM involves understanding the regulatory mechanisms of insulin secretion in pancreatic β-cells. Pancreatic β-cells play a pivotal role in maintaining glucose homeostasis. Although glucose is the primary stimulator of insulin secretion, certain amino acids also have regulatory roles. Traditional views have held that while glutamine contributes to insulin secretion, it does not directly influence this process in the absence of glutamate dehydrogenase (GDH) activation. We found that glutamine increases insulin secretion independently of GDH activation in INS-1 832/13 cells. Therefore, the aim of the thesis is to elucidate the role of glutamine in insulin secretion and examining its regulatory effects on glucose metabolism in pancreatic β-cells. To achieve this, we leverage advanced methodologies, including metabolomics and network analysis, to provide a comprehensive understanding of these complex mechanisms. Methods and results: Our initial findings presented a surprising challenge to the conventional belief that glutamine induces insulin secretion only in the presence of leucine. We discovered that glutamine (independent of leucine) could increase insulin secretion in a dose-dependent manner in INS-1 832/13 cells. To delve further into this phenomenon, we employed inhibitors of key enzymes in glutamine metabolism - GDH (responsible for glutamate oxidation) and glutaminase (converts glutamine to glutamate). Our results highlighted that while inhibiting GDH did not alter insulin secretion, inhibiting glutaminase significantly reduced the insulin-secretory response to glutamine in INS-1 832/13 cells. This finding indicated that the effect of glutamine on insulin secretion operates independently of glutamate oxidation. Our study also investigated the regulatory role of glutamine in insulin secretion and on the rate of glucokinase (GK) in response to glucose levels. We observed that increasing concentrations of glutamine affected both the dynamics of insulin secretion and the kinetic parameters of GK in INS-1 832/13 cells, suggesting a regulatory relationship between glutamine and glucose phosphorylation that had not been previously observed. To deepen our understanding of the intricate relationship, we developed a novel analytical approach that combined network analysis with metabolomics. This innovative method provided an unbiased assessment of the interrelationships between various metabolites, enabling a more comprehensive understanding of the metabolic pathways and their interactions. A striking outcome of our network analysis was the identification of proline as a key metabolite in the glutamine-glucose crosstalk. To validate this link, we conducted siRNA knockdown experiments targeting proline synthesis in INS-1 832/13 cells. Knockdown of these genes resulted in a significant reduction in insulin secretion in response to glutamine. Further, this effect could be rescued by the addition of proline, thereby underscoring the essential role of proline in glutamine-mediated insulin secretion. Furthermore, in vitro enzymatic assays using INS-1 832/13 cell extracts and purified rat GK revealed proline- mediated changes in kinetic parameters consistent with glutamine-mediated alterations in GK activity in live INS-1 832/13 cells. Additionally, a thermal stability assay demonstrated that the melting temperature of purified rat GK varied with proline concentration, suggesting a direct interaction of proline with GK. This effect of glutamine on insulin secretion was also observed in isolated rat islets, thereby affirming the physiological relevance of our results. Moreover, the thermal stability assay using purified human GK confirmed that this interaction is conserved in humans as well. Conclusion and outlook: This study reveals a novel mechanism by which glutamine metabolism, through proline synthesis, regulates GK activity and thereby influences insulin secretion in pancreatic β-cells. The outlook of this thesis opens promising avenues for future research and potential clinical applications, particularly in the context of T2DM management. Key areas for future exploration include translating these findings to in vivo models and clinical settings could open new therapeutic avenues for T2DM, emphasizing the importance of modulating glutamine and proline metabolism for more effective regulation of insulin secretion. Investigating the direct causal relationship between plasma proline levels and diabetic conditions could not only deepen our understanding of diabetes but also provide a potential biomarker for early risk assessment. Understanding the precise molecular interactions between proline and GK could allow the identification of potential novel binding sites for therapeutic intervention to enhance GK activity and improve glucose regulation. Extending this research to human cells and examining its implications in diabetes and other metabolic disorders is a vital next step, offering potential for significant advancements in diabetes treatment and understanding of metabolic diseases.:Table of Contents List of abbreviations List of figures List of tables 1. Introduction 1.1. Type 2 Diabetes 1.1.1. Definition, epidemiology, and risk factors 1.1.2. Pathophysiology of T2DM 1.1.3. Preserving or enhancing β-cell function 1.2. Physiology of pancreatic β-cells 1.2.1. Overview of glucose-stimulated insulin secretion 1.2.2. Regulation of glucose entry into the β-cells 1.2.3. Role of glucokinase as a glucose sensor 1.2.4. Regulation of mitochondrial metabolism in insulin secretion 1.2.5. Regulation of amino acid mediated insulin secretion 1.3. Metabolomics approach in studying β-cell function 1.4. Network analysis in metabolomics data analysis and interpretation 2. Aims of the study 3. Materials and Methods 3.1. Materials 3.1.1. INS-1 832/13 cells 3.1.2. Chemicals, solutions, and buffers for cell culture 3.1.3. Chemicals, solutions, and buffers for molecular and metabolic experiments 3.1.4. Software 3.2. Methods 3.2.1. Cell culture 3.2.1.1. Culturing INS-1 832/13 cells 3.2.1.2. Cryopreservation and thawing of INS1 832/13 cells 3.2.1.3. Isolation of rat islets 3.2.2. Expression and Purification of GST-fusion GK Proteins in E. coli. 3.2.3. Insulin secretion studies in INS1 832/13 cells 3.2.3.1. Effect of Glutamine on insulin secretion 3.2.3.2. Effect of chronic and acute exposure of glutamine on insulin secretion 3.2.3.3. Glutamine-responsive insulin secretion 3.2.3.4. Effect of glutamate oxidation in glutamine-mediated insulin secretion 3.2.3.5. Effect of glutamine on glucose-responsive insulin secretion 3.2.3.6. Effect of 2DG on glucose stimulated insulin secretion 3.2.3.7. Insulin and total protein quantification 3.2.4. Metabolomic experiments in INS-1 832/13 cells 3.2.4.1. Effect of specific perturbations on metabolomic profile 3.2.4.2. Effect of glutamine on metabolomic profile 3.2.5. Metabolomic analyses 3.2.5.1. LC-MS/MS method for characterization of metabolites 3.2.5.2. Metabolite concentration calculation 3.2.6. Network analysis 3.2.6.1. Metabolite network construction 3.2.6.2. Comparative metabolite analysis with weighted network metrics 3.2.7. GK kinetic studies 3.2.7.1. GK activity with GK activator in INS-1 832/13 cells 3.2.7.2. GK activity with glutamine in INS1 cells & rat islets 3.2.7.3. GK kinetics measurement 3.2.7.4. In vitro GK kinetic studies using cell extracts & purified GK enzyme 3.2.8. Gene expression analysis 3.2.8.1. RNA isolation 3.2.8.2. cDNA synthesis 3.2.8.3. qPCR 4. Results 4.1. Glutamine mediated insulin secretion in INS-1 832/13 cells 4.1.1. Glutamine alone stimulates insulin secretion 4.1.2. Glutamine amplifies insulin secretion independently of glutamate oxidation 4.2. Glutamine mediated insulin secretion and its impact on glucose responsiveness 4.2.1. Glutamine modulates the regulation of insulin secretion in INS-1 832/13 cells 4.2.2. Live cell GK activity measurement using 2DG uptake in INS-1 832/13 cells 4.2.3. Glutamine modulates GK activity in INS-1 832/13 cells 4.3. Identifying the glutamine-derived factor regulating GK activity 4.3.1. Network analysis to identify key metabolites associated with specific perturbations 4.3.2. Glutamine-induced insulin secretion is mediated by proline 4.3.3. Proline modulates GK activity in INS-1 832/13 cell extracts 4.3.4. Proline modulates activity of purified rat GK 4.3.5. Thermal stability assays in rat GK 4.3.6. siRNA knockdown of proline synthesis 4.4. Glutamine modulates insulin secretion and GK activity in rat islets 4.5. Proline interacts and modulate GK in human 5. Discussion 5.1. Reevaluating glutamine-mediated insulin secretion in pancreatic β-cells 5.2. Novel role of glutamine-mediated modulation of GK activity and insulin secretion in pancreatic β-cells 5.3. Network analysis as a tool to unravel complex interactions in metabolic research 5.4. Proline as a novel modulator of GK 5.5. Contrasting role of glutamine in pancreatic and liver metabolism 6. References 7. Summary 8. Zussammenfassung 9. Acknowledgements 10. Declaration / Hintergrund und Ziele: Typ-2-Diabetes mellitus (T2DM) stellt eine bedeutende globale Herausforderung für die Gesundheit dar und ist durch eine gestörte Insulinsekretion und/oder -wirkung gekennzeichnet. Ein entscheidender Aspekt bei der Behandlung von T2DM ist das Verstehen von Regulationsmechanismen der Insulinsekretion in den β-Zellen der Pankreas. Die β-Zellen der Bauchspeicheldrüse spielen eine zentrale Rolle bei der Aufrechterhaltung der Glukosehomöostase. Obwohl Glukose der primäre Stimulator der Insulinsekretion ist, spielen bestimmte Aminosäuren auch eine regulierende Rolle. Nach traditioneller Auffassung trägt Glutamin zwar zur Insulinsekretion bei, hat aber keinen direkten Einfluss auf diesen Prozess, es sei denn, er wird durch Glutamatdehydrogenase (GDH) aktiviert. Wir fanden heraus, dass Glutamin die Insulinsekretion unabhängig von der GDH-Aktivierung in INS-1 832/13-Zellen erhöht. Ziel dieser Arbeit war es daher, die Rolle von Glutamin bei der Insulinsekretion aufzuklären und seine regulierenden Effekte auf den Glukosestoffwechsel in β-Zellen der Pankreas zu untersuchen. Um dies zu erreichen, nutzen wir fortschrittliche Methoden, einschließlich Metabolomik- und Netzwerkanalysen, um ein umfassendes Verständnis dieser komplexen Mechanismen zu erlangen. Methoden und Ergebnisse: Unsere anfänglichen Ergebnisse stellten eine überraschende Inhomogenität zur herkömmlichen Annahme dar, dass Glutamin die Insulinsekretion nur in der Anwesenheit von Leucin induziert. Wir entdeckten, dass Glutamin (unabhängig von Leucin) die Insulinsekretion in INS-1 832/13-Zellen dosisabhängig steigern kann. Um dieses Phänomen näher zu untersuchen, setzten wir Hemmstoffe von Schlüsselenzymen des Glutaminstoffwechsels ein - GDH (verantwortlich für die Glutamatoxidation) und Glutaminase (konvertiert Glutamin zu Glutamat). Unsere Ergebnisse zeigten, dass die Hemmung der GDH die Insulinsekretion nicht modifizierte, während die Hemmung der Glutaminase die Insulinsekretionsantwort auf Glutamin in INS-1 832/13-Zellen deutlich verringerte. Diese Erkenntnis deutet darauf hin, dass die Wirkung von Glutamin auf die Insulinsekretion unabhängig von der Glutamatoxidation ist. In dieser Studie untersuchten wir weiterhin die regulatorische Rolle von Glutamin bei der Insulinsekretion und für die GK-Rate in Abhängigkeit vom Glukosespiegel. Wir stellten fest, dass steigende Glutaminkonzentrationen sowohl die Dynamik der Insulinsekretion als auch die kinetischen Parameter der Glucokinase (GK) in INS-1 832/13-Zellen beeinflussten, was auf eine bisher nicht erkannte regulatorische Beziehung zwischen Glutamin und Glukosephosphorylierung schließen lässt. Um unser Verständnis dieser komplexen Beziehung zu vertiefen, entwickelten wir einen neuartigen analytischen Ansatz, der die Netzwerkanalyse mit der Metabolomforschung kombinierte. Diese innovative Methode ermöglichte eine unvoreingenommene Bewertung der Wechselbeziehungen zwischen verschiedenen Metaboliten und damit ein umfassenderes Verständnis der Stoffwechselwege und ihrer Wechselwirkungen. Ein bemerkenswertes Ergebnis unserer Netzwerkanalyse war die Identifizierung von Prolin als Schlüsselmetabolit im Glutamin-Glukose-Crosstalk. Um diese Verbindung zu bestätigen, führten wir siRNA-Knockdown-Experimente durch, die auf die Prolinsynthese in INS-1 832/13-Zellen abzielten. Die Ausschaltung dieser Gene führte zu einer deutlichen Verringerung der Insulinsekretion als Reaktion auf Glutamin. Bemerkenswerterweise konnte dieser Effekt durch die Zugabe von Prolin wiederhergestellt werden, was die wesentliche Rolle von Prolin bei der Glutamin-vermittelten Insulinsekretion unterstreicht. Darüber hinaus ergaben in vitro Enzymassays mit INS-1 832/13-Zellextrakten und gereinigter Ratten-GK Prolin-vermittelte Veränderungen der kinetischen Parameter, die mit Glutamin-vermittelten Veränderungen der GK-Aktivität in lebenden INS-1 832/13-Zellen übereinstimmen. Darüber hinaus zeigte ein Thermal Stability Assay, dass die Schmelztemperatur von gereinigtem Ratten-GK mit der Prolin-Konzentration variierte, was auf eine direkte Interaktion von Prolin mit der GK hindeutet. Dieser Effekt von Glutamin auf die Insulinsekretion wurde auch in aus Ratten isolierten Langerhansschen Inseln beobachtet, was die physiologische Relevanz unserer Ergebnisse bestätigt. Darüber hinaus bestätigte der Thermal Stability Assay mit gereinigter menschlichen GK, dass diese Interaktion auch beim Menschen konserviert ist. Schlussfolgerung und Ausblick: Diese Studie enthüllt einen neuartigen Mechanismus, durch den der Glutamin-Stoffwechsel über die Prolin-Synthese die GK-Aktivität reguliert und dadurch die Insulinsekretion in den β-Zellen der Bauchspeicheldrüse beeinflusst, was bestehende Paradigmen in Frage stellt. Perspektivisch ermöglichen die Erkenntnisse dieser Arbeit vielversprechende Wege für die zukünftige Forschung und potenzielle klinische Anwendungen, insbesondere im Zusammenhang mit T2DM-Management. Zu den Schlüsselbereichen der zukünftigen Forschung gehören die Übertragung dieser Ergebnisse auf in vivo Modelle und klinische Studien, die neue therapeutische Wege für T2DM eröffnen könnten und die Bedeutung der Modulation des Glutamin- und Prolin-Stoffwechsels für eine effektivere Regulierung der Insulinsekretion unterstreichen. Die Untersuchung des direkten kausalen Zusammenhangs zwischen Plasmaprolinspiegeln und diabetischen Erkrankungen könnte nicht nur unser Verständnis von Diabetes vertiefen, sondern auch einen potenziellen Biomarker für eine frühzeitige Risikobewertung liefern. Die Entschlüsselung der genauen molekularen Wechselwirkungen zwischen Prolin und GK könnte die Identifizierung potenzieller neuer Bindungsstellen für therapeutische Eingriffe zur Steigerung der GK- Aktivität und zur Verbesserung der Glukoseregulierung ermöglichen. Die Erweiterung dieser Forschung auf menschliche Zellen und die Untersuchung ihrer Auswirkungen auf Diabetes und andere Stoffwechselstörungen ist ein wichtiger nächster Schritt, der das Potenzial für bedeutende Fortschritte bei der Behandlung von Diabetes und dem Verständnis von Stoffwechselkrankheiten bietet.:Table of Contents List of abbreviations List of figures List of tables 1. Introduction 1.1. Type 2 Diabetes 1.1.1. Definition, epidemiology, and risk factors 1.1.2. Pathophysiology of T2DM 1.1.3. Preserving or enhancing β-cell function 1.2. Physiology of pancreatic β-cells 1.2.1. Overview of glucose-stimulated insulin secretion 1.2.2. Regulation of glucose entry into the β-cells 1.2.3. Role of glucokinase as a glucose sensor 1.2.4. Regulation of mitochondrial metabolism in insulin secretion 1.2.5. Regulation of amino acid mediated insulin secretion 1.3. Metabolomics approach in studying β-cell function 1.4. Network analysis in metabolomics data analysis and interpretation 2. Aims of the study 3. Materials and Methods 3.1. Materials 3.1.1. INS-1 832/13 cells 3.1.2. Chemicals, solutions, and buffers for cell culture 3.1.3. Chemicals, solutions, and buffers for molecular and metabolic experiments 3.1.4. Software 3.2. Methods 3.2.1. Cell culture 3.2.1.1. Culturing INS-1 832/13 cells 3.2.1.2. Cryopreservation and thawing of INS1 832/13 cells 3.2.1.3. Isolation of rat islets 3.2.2. Expression and Purification of GST-fusion GK Proteins in E. coli. 3.2.3. Insulin secretion studies in INS1 832/13 cells 3.2.3.1. Effect of Glutamine on insulin secretion 3.2.3.2. Effect of chronic and acute exposure of glutamine on insulin secretion 3.2.3.3. Glutamine-responsive insulin secretion 3.2.3.4. Effect of glutamate oxidation in glutamine-mediated insulin secretion 3.2.3.5. Effect of glutamine on glucose-responsive insulin secretion 3.2.3.6. Effect of 2DG on glucose stimulated insulin secretion 3.2.3.7. Insulin and total protein quantification 3.2.4. Metabolomic experiments in INS-1 832/13 cells 3.2.4.1. Effect of specific perturbations on metabolomic profile 3.2.4.2. Effect of glutamine on metabolomic profile 3.2.5. Metabolomic analyses 3.2.5.1. LC-MS/MS method for characterization of metabolites 3.2.5.2. Metabolite concentration calculation 3.2.6. Network analysis 3.2.6.1. Metabolite network construction 3.2.6.2. Comparative metabolite analysis with weighted network metrics 3.2.7. GK kinetic studies 3.2.7.1. GK activity with GK activator in INS-1 832/13 cells 3.2.7.2. GK activity with glutamine in INS1 cells & rat islets 3.2.7.3. GK kinetics measurement 3.2.7.4. In vitro GK kinetic studies using cell extracts & purified GK enzyme 3.2.8. Gene expression analysis 3.2.8.1. RNA isolation 3.2.8.2. cDNA synthesis 3.2.8.3. qPCR 4. Results 4.1. Glutamine mediated insulin secretion in INS-1 832/13 cells 4.1.1. Glutamine alone stimulates insulin secretion 4.1.2. Glutamine amplifies insulin secretion independently of glutamate oxidation 4.2. Glutamine mediated insulin secretion and its impact on glucose responsiveness 4.2.1. Glutamine modulates the regulation of insulin secretion in INS-1 832/13 cells 4.2.2. Live cell GK activity measurement using 2DG uptake in INS-1 832/13 cells 4.2.3. Glutamine modulates GK activity in INS-1 832/13 cells 4.3. Identifying the glutamine-derived factor regulating GK activity 4.3.1. Network analysis to identify key metabolites associated with specific perturbations 4.3.2. Glutamine-induced insulin secretion is mediated by proline 4.3.3. Proline modulates GK activity in INS-1 832/13 cell extracts 4.3.4. Proline modulates activity of purified rat GK 4.3.5. Thermal stability assays in rat GK 4.3.6. siRNA knockdown of proline synthesis 4.4. Glutamine modulates insulin secretion and GK activity in rat islets 4.5. Proline interacts and modulate GK in human 5. Discussion 5.1. Reevaluating glutamine-mediated insulin secretion in pancreatic β-cells 5.2. Novel role of glutamine-mediated modulation of GK activity and insulin secretion in pancreatic β-cells 5.3. Network analysis as a tool to unravel complex interactions in metabolic research 5.4. Proline as a novel modulator of GK 5.5. Contrasting role of glutamine in pancreatic and liver metabolism 6. References 7. Summary 8. Zussammenfassung 9. Acknowledgements 10. Declaration

The purpose of this study was to develop a set of guidelines to enable teachers to support children with diabetes. The aspects of support include the physical, emotional, social and cognitive aspects that have an effect on a child with diabetes. A literature study and an empirica l investigation were und ertaken to investigate which factors would enable teachers to become better sources of support in school. Semi - structured interviews were conducted with teachers to determi ne their knowledge about diabetes . Parents who have children with diabetes were also interviewed to determine what support they required from teachers. The results of the study culminated in a set of guidelines for teachers. / Psychology of Education / M. Ed. (Psychology of Education)

Coronary artery disease (CAD), Hypertension (Ht) and Type 2 Diabetes Mellitus (T2DM) are all global health problems. This is particularly evident amongst South Asian population groups. The conventional risk factors do not fully explain the higher prevalence of these diseases among South Asians. The endothelial Nitric Oxide Synthase (eNOS) gene is responsible for the production of Nitric Oxide (NO), which may contribute to the physiology of all three disease states. Endothelial dysfunction (which is characterised by a reduction in basal NO) has been shown to be present in, or prior to all three diseases. Numerous variations exist within the eNOS gene, of these variations three have been shown to have a possible functional effect. The first is the Glu298Asp polymorphism within the exon region of the gene, resulting in an amino acid substitution of Glutamate (Glu) to Aspartate (Asp). The second, known as the T-786C polymorphism, is a thymine to cytosine mutation at position -786 in the promoter region. Finally a VNTR polymorphism in Intron 4 causes either a 4 27bp repeat or a 5 27bp repeat. It is hypothesised that these variations could have an effect on the ability of eNOS to produce NO and thus may increase the risk or contribute to the development of the diseases. Previous studies on these variants have shown conflicting results and further studies are warranted to understand and confirm the role of eNOS gene polymorphisms in cardio-metabolic diseases. There is very limited research into the distributions of these genetic variants and their interaction in diseases processes in North Indian populations. Objectives: 1. To analyse through a case control study three different polymorphisms of the eNOS gene for possible association with Coronary Artery Disease (CAD), Hypertension (Ht) and Type 2 Diabetes Mellitus (T2DM) in North Indian population groups. 2. To statistically evaluate descriptive statistics including; age, gender, smoking, dietary behaviours and lipid parameters for possible influence on disease and potential interaction with genetic polymorphisms. 3. To evaluate linkage disequilibrium between the three eNOS variants and carryout haplotype analysis to work out haplotype risk in different diseases. 4. To analyse through a case control study the deletion variant of the Angiotensin-converting enzyme (ACE) gene for possible association with Coronary Artery Disease (CAD), Hypertension (Ht) and Type 2 Diabetes Mellitus (T2DM) in North Indian population groups. 5. To determine a possible interactive effect of the eNOS polymorphisms with the ACE polymorphism. Subjects and Methods: The Glu298Asp and Intron 4 variants were genotyped using a PCR-RFLP technique, the T-786C variant was genotyped using a real time-PCR technique. The ACE deletion variant was also genotyped using a standard PCR technique. The genotyping was undertaken in a total of 457 CAD patients and 220 matched controls from Lucknow, Uttar Pradesh in North India, 319 T2DM patients and 307 matched controls from Punjab, North India and 210 Ht and 162 matched controls, also from Punjab, North India. Results: CAD: The Glu298Asp was significantly associated with CAD among smokers (TT+GT vs. GG OR=2.84 (CI: 1.61-5.0), p<0.001). The Intron 4 variant was also significantly associated with CAD in a smoking dependent manner (4aa+4ab vs. 4bb OR=0.56 (CI: 0.33-0.96). The T-786C variant showed no overall influence on CAD risk. There was also evidence for both synergistic and haplotypic effects of the eNOS gene on CAD status (haplotype G-C-4b OR=4.76 (CI: 1.43-15.78), p<0.001). The ACE genetic variant was confirmed to be a strong independent risk factor for CAD under a dominant model (OR=2.18 (CI: 1.46-3.25), p<0.001). There was no evidence for an interactive effect between the ACE deletion and any of the three eNOS variants incorporated in the current study. Ht: The Glu298Asp variant was not shown to increase Ht risk, with a reduced risk association found under a recessive model (OR=0.316 (CI:0.089-1.116)), p=0.061). The T-786C variant s role in disease remained unclear with the findings showing a non significant increased risk. The Intron 4 variant was also shown to increase Ht risk, in a non significant manner. Sufficiently powered studies would be required to clarify these possible associations. The combined analysis, using logistic regression and haplotype analysis revealed no significant associations, but there was a possible protective effect of the T-C-4b haplotype (OR=0.46 (CI: 0.21-1.01), p=0.054). The ACE gene variant was confirmed to be a strong independent risk factor for Ht under a recessive model (OR=1.81 (CI: 1.20-2.74), p=0.01). Again there was no evidence for an interactive effect between the ACE deletion and any of the three eNOS variants in hypertension. T2DM: The Glu298Asp variant was found to be associated with T2DM under a dominant model, the protective effect remained significant following adjustment for conventional risk factors and other gene variants (OR=0.407 (CI: 0.231-0.717), p=0.002). The T-786C variant showed no overall influence on T2DM risk. The Intron 4 variant also found no overall influence. Haplotype analysis found the T-T-4b was found to be significantly protective for T2DM (OR=0.41 (CI: 0.26-0.65), p=0.0002). Finally the ACE gene variant was confirmed to be a risk factor for T2DM under a dominant model (OR=2.62 (CI: 1.51-4.54), p=0.001). Overall Conclusions: To conclude, this study successfully identified the frequency of three eNOS gene variants and the ACE deletion variant in three complex diseases within north Indian populations. There is a clear role of the eNOS gene in all three diseases and consequently the genetic variants have susceptible/protective associations. The association with disease was found to be present at an individual level, in association with risk factors and at a haplotypic level. These findings warrant further studies to confirm and untangle the genetics of complex diseases and genetic risk profiles calculations which will contribute to the field of medical genomics/personalised medicare and interventions among North Indian populations.

Hintergrund: Bei Diabetes Typ 2 gilt die Selbstbehandlung als wesentlicher Therapie-bestandteil. In vielen Forschungsarbeiten geht es deshalb um Ansatzpunkte, wie man Erkrankte besser zu gesundheitsfördernden Maßnahmen motivieren kann. Solche - gutgemeinten - pädagogischen Zielsetzungen verstellen oft den Blick auf das subjek-tive Erleben dieser Menschen. Fragestellung: In der vorliegenden Arbeit standen da-her die Krankheitserfahrungen bei Diabetes Typ 2 im Vordergrund. Während des Analyseprozesses stellte sich „Verzicht“ als beherrschende Erfahrung heraus. Daher sollte die Ausstrahlung der Verzichtserfahrung in alle Lebensbereiche, vor allem als mögli-che Belastung für die Krankheitsbewältigung, die sozialen Interaktionen und für die alltägliche Handlungsorientierung untersucht werden. Methode: Als Material lagen 35 für das Website-Projekts „krankheitserfahrungen.de“ erhobene narrative Interviews vor. Aus diesen wurden im Sinne eines Theoretical Samplings Ausschnitte aus Inter-views mit 14 Personen ausgewählt und nach Methoden der Grounded Theory ausge-wertet. Ergebnisse: Alle Interviewten standen unter dem Druck, auf ein genussvolles Leben zu verzichten, was ihnen ungerecht erschien. Als „Prüfmarken“ gelungenen Verzichts wurden Laborwerte und Körpermaße herangezogen - von Ärzten, aber auch von Personen im privaten sozialen Umfeld und von den Interviewten selbst. Diese „sichtbaren“ Kriterien wurden manchmal positiv im Sinne eines selbst erreichten Ergebnisses („Verzicht“) erlebt, manchmal abgewehrt als ungerechte äußere Beurteilung ihres Verhaltens (als „Maßlosigkeit“). Das Denken in den Kategorien Verzicht und Maßlosigkeit ging mit der ständigen Angst vor moralischer Diskreditierung einher und fand auch Eingang in die eigenen „Regeln“, in denen Interviewte selbst bestimmten, was „gesunde“ und „ungesunde“ Lebensmittel sind. Dabei ergab sich eine gewisse Freiheit, diese Regeln als zu den Bedürfnissen passend zu gestalten. Manchmal konnte Verzicht so zu positiven neuen Erfahrungen führen. Schlussfolgerungen: Menschen mit Diabetes Typ 2 haben die medizinische und gesellschaftliche Aufforderung nach Verzicht verinnerlicht und stehen dadurch unter starkem Druck. Statt diesen durch pädagogische Strategien noch weiter zu erhöhen, erscheint es sinnvoller, wenn Ärzte mit ihren Patienten über deren „unsichtbare“ Bemühungen sprechen und sie da-bei begleiten.

La résistance à l’insuline et le diabète de type 2 (DT2) sont caractérisés par une hyperlipidémie. Le but de cette étude est de déterminer si le DT2 contribue au dérèglement du métabolisme du cholestérol au niveau du petit intestin et du foie du Psammomys obesus, un modèle animal nutritionnel d’induction de la résistance à l’insuline et du DT2. L’absorption intestinale du cholestérol est diminuée chez les animaux diabétiques. Cette diminution est associée à une baisse (i) de l’expression génique et protéique de NPC1-L1 qui joue un rôle primordial dans l’absorption du cholestérol au niveau des entérocytes; et (ii) de l’ARNm de l’ABCA1 responsable de l’efflux de cholestérol des cellules intestinales à l’apolipoprotéine A-I et aux HDLs. En ce qui a trait aux transporteurs SR-B1 et Annexin II, aucune différence n’a été observée au niveau intestinal. Toutefois, une diminution significative de l’expression génique de l’ABCG5, un intervenant majeur dans la sécrétion du cholestérol des entérocytes vers la lumière intestinale, est mesurée chez les animaux diabétiques. De plus, l’expression protéique est diminuée pour le PCSK9 et augmentée pour le LDLr au niveau du jéjunum, tandis que la quantité de protéine de l’enzyme HMG-CoA réductase est régulée à la baisse chez les Psammomys obesus diabétiques. Finalement, de tous les facteurs de transcription testés seule une augmentation de LXR et une diminution de PPAR/δ sont détectées au niveau de l’intestin. Au niveau hépatique, il y a (i) une augmentation de la masse protéique de NPC1-L1, SR-BI et Annexin II; (ii) une élévation l’ARNm de SR-BI; (iii) une diminution du contenu protéique de ABCG8 et de l’expression génique de l’ABCG5 et de l’ABCA1; et (iv) une élévation de l’ARNm de LXR et de PPAR/δ, tout comme une baisse de l’expression protéique de SREBP-2. Somme toute, nos résultats montrent que le développement du diabète de type 2 chez le Psammomys obesus entraîne un changement dans la machinerie intra-entérocytaire et hépatocytaire, qui mène à un dérèglement de l’homéostasie du cholestérol. / Insulin resistance and type 2 diabetes (T2D) are characterized by hyperlipidemia. The aim of the present study was to elucidate whether T2D contributes to abnormal cholesterol homeostasis in the small intestine and liver of Psammomys obesus, a model of nutritionally induced insulin resistance and type 2 diabetes. Diabetic animals exhibited a lower intestinal cholesterol uptake, which was associated with a decrease in (i) the gene and protein expression of NPC1L1, which plays a pivotal role in cholesterol incorporation in the enterocytes; and (ii) mRNA of ABCA1 that mediates cholesterol efflux from intestinal cells to apolipoprotein A-I and HDL. No changes were observed in the other intestinal transporters SR-BI and Annexin II. On the other hand, in diabetic animals, a significant mRNA decrease was noticed in ABCG5 responsible for the secretion of absorbed cholesterol back into the lumen. Furthermore, jejunal PCSk9 protein was diminished and LDLr was raised, along with a significant downregulation in jejunal HMG-CoA reductase in diabetic Psammomys obesus. Finally, among the transcription factors tested, only an increase in LXR and a decrease in PPAR/δ were detected in the intestine. In the liver, there was (i) an augmentation in the protein mass of NPC1L1, SR-BI and Annexin II; (ii) an upregulation of SR-BI mRNA; (iii) a fall in ABCG8 protein content, ABCG5 mRNA and ABCA1 mRNA; and (iv) an augmentation in LXR and PPAR/δ mRNA, as well as a drop in SREBP-2 protein. Overall, our findings show that the development of type 2 diabetes in Psammomys obesus modifies the whole intra-enterocyte and hepatocyte machinery, causing alterations in cholesterol homeostasis.

Par la sécrétion d’adipokines, le tissu adipeux blanc viscéral présent chez des patients souffrant d’obésité promeut l’installation d’altérations métaboliques telles que l’intolérance au glucose, la résistance à l’insuline et le diabète de type 2. Les complications cardiovasculaires, en particulier l’athérosclérose, sont les principales causes de mortalité chez les patients atteints de diabète de type 2. Il a été démontré que la fraction vasculaire stromale du tissu adipeux est composée de cellules régénératives dérivées du tissu adipeux (CRTA) et que ces cellules possèdent des caractéristiques des cellules progénitrices stromales (CPS). L’impact de l’intolérance au glucose et du diabète de type 2 sur les adipocytes sont assez bien documentés. Par contre, les conséquences de ces pathologies sur le comportement des CRTA n’ont pas été mesurées d’une façon approfondie. Plus particulièrement, l’impact de ces altérations métaboliques sur le potentiel de différenciation des CRTA en adipocytes et en cellules endothéliales n’a pas été étudié. Ce projet a pour but d’évaluer, dans un modèle murin, l’effet de ces altérations métaboliques sur l’équilibre de la différenciation in vitro des CRTA en adipocytes ou en cellules endothéliales. L’intolérance au glucose et le diabète de type 2 ont été induit chez les souris par la prise de deux diètes riches en acides gras de provenance végétale (DV) ou animale (DA). L’impact de l’origine des acides gras sur la différenciation des CRTA a également été étudié. Pour ce faire, une mise au point de la culture cellulaire des CRTA s’est avérée nécessaire et compte pour une partie de ces travaux de maîtrise. Nos travaux ont démontré en premier lieu, que le DMSO est un agent qui conserve la viabilité et les propriétés progénitrices des CRTA suite à leur congélation. De plus, parmi les matrices testées, le collagène s’est avéré être celle qui conserve le mieux les caractéristiques des progéniteurs et même, qui enrichie la population cellulaire ensemencée en cellules progénitrices. La densité cellulaire des cellules non-adipeuses du tissu adipeux s’avère être significativement plus élevée chez les souris du groupe de la DV comparativement aux souris contrôles. De plus, l’évaluation in vitro de la différenciation adipogénique démontre un potentiel de différenciation plus important pour les CRTA provenant des souris de la DV par rapport au groupe contrôle et à la DA. Cependant, la différenciation en cellules endothéliales est inhibée chez les CRTA de la DV, comparativement à un retard de ce processus pour la DA. Nos travaux suggèrent que le potentiel de différenciation adipogénique et endothéliale des CRTA est affecté par le statut métabolique des souris ainsi que par la nature de la diète. Ces résultats mettent en lumière pour la première fois l’importance d’évaluer le comportement des CRTA en fonction du statut métabolique du donneur, un paramètre pouvant avoir un impact majeur dans l’utilisation des CRTA autologues en thérapie cellulaire pour la réparation de tissus vasculaires chez des patients diabétiques. / The secretion of a large number of bioactive mediators by adipose tissue in abdominal obesity promotes metabolic diseases such as glucose intolerance, insulin resistance and type 2 diabetes. Cardiovascular complications, in particular atherosclerosis, are the leading causes of mortality in patients with type 2 diabetes. It has been shown that the stromal vascular fraction of adipose tissue comprised adipose-derived regenerative cells (ADRC) and that these cells possess progenitor cells characteristics. Effects of glucose intolerance and type 2 diabetes on adipocytes are well documented. However, consequences of these pathologies on ADRC behaviors are not well understood. Particularly, the impact of these metabolic alterations on the adipogenic and endothelial differentiation potential of ADRC has not been investigated. Aim of this project was to evaluate, in a murine model, the effect of these metabolic alterations on the balance of the in vitro ADRC differentiation into adipocytes or endothelial cells. Glucose intolerance and type 2 diabetes were induced in mice by the intake of two high-fat diets enriched in vegetal (VD) or animal (AD) fat. The impact of the fat origin on the ADRC differentiation was then evaluated. To do this, the development of cellular culture conditions of ADRC was necessary and an important part of this work. Our results suggest that DMSO is an efficient cryoprotective agent that conserves the viability and progenitor properties of ADRC following their freezing. Moreover, among tested scaffolds for the culture of ADRC, collagen is the best matrix to maintain progenitor characteristics and this matrix enriched the cellular population in progenitor cells. The cellular density of non-adipose cells fraction in the adipose tissue was significantly more elevated for VD mice than for the control group. The in vitro evaluation of adipogenic differentiation demonstrated an increase in the differentiation potential for ADRC from VD group compared to AD and control groups. In addition, the endothelial differentiation was abrogated for ADRC from VD group, compared to a delayed one for AD. These results suggest that the adipogenic and endothelial differentiation potential of ADRC and, consequently, the balance between emerging mature cells, are affected by the metabolic status of mice together with the nature of fatty acids. These results highlight, for the first time, the importance to evaluate the ADRC behavior in function to the metabolic status of donor, a parameter that could have an important impact in the use of autologous ADRC in cell-based therapy for the repair of injured vascular tissues in diabetic patients.

The prevalence of childhood obesity and Type 2 Diabetes Mellitus (T2DM) has increased during recent decades. T2DM is accompanied with functional changes in the islets of Langerhans, which can be identified early in the pathogenesis. The aim of this thesis was to explore how metabolic changes caused by obesity early in life relate to islet function prior to overt T2DM. To address this, Uppsala Longitudinal Study of Childhood Obesity (ULSCO) was established (paper I). Initially, the association between palmitate and insulin secretion was investigated using a translational approach with obese and lean normoglycemic juveniles and isolated human islets (paper II). Secondly, dynamics of islet-hormones insulin and glucagon, and gut-hormones glucagon like-peptide 1 (GLP-1) and glicentin (paper III) and magnetic resonance imaging of pancreatic fat fraction (PFF) (paper IV) were studied in association to glucose tolerance and beta-cell function. Finally, a novel method of analysing shape features of oral glucose tolerance test (OGTT) curves was introduced and evaluated (paper V). Obese subjects had high prevalence of prediabetes and metabolic syndrome (MetS) (paper I). In obese pre-pubertal children with elevated palmitate levels, hyperinsulinemia was observed (paper II). In contrast, obese pubertal adolescents with similar palmitate levels showed moderate insulin levels during OGTT with delayed first phase insulin response. To explore mechanisms for these variations, isolated human islets were exposed to palmitate for different time periods in vitro. After 2 days accentuated insulin response was observed. Impaired beta-cell function and apoptosis were evident after 7 days, however. Hyperglucagonemia and disturbed GLP-1 and glicentin levels were associated with obesity and glycaemic status, with fasting glicentin being predictive of prediabetes (paper III). Furthermore, PFF was increased in obese subjects and associated to MetS and visceral adipose tissue, but not to beta-cell function (paper IV). OGTT curves were converted into geometric centres, centroids, which correlated with differences in glucose tolerance (paper V). In conclusion, the islet function in obese children was associated with elevated levels of palmitate, but not pancreatic fat. Fasting palmitate and glicentin levels, as well as centroid analyses of OGTT curves, could potentially identify obese children at risk of prediabetes and subsequent T2DM.

Au cours des dernières années, il est devenu évident que les sociétés des pays industrialisés sont à haut risque de maladies métaboliques. Une alimentation riche en énergie (lipide/glucide), combinée à une sédentarité accrue, est un facteur environnemental contribuant à l'augmentation de la prévalence de maladies reliées spécifiquement à des troubles endocriniens comme l'obésité et le diabète. Le traitement de ces désordres métaboliques doit donc passer par la connaissance et la compréhension des mécanismes moléculaires qui contrôlent ces désordres et le développement de traitements ciblés vers les facteurs responsables. Le tissu adipeux est une glande endocrine qui sécrète des substances, regroupées sous le terme d'adipokines, qui contrôlent l'homéostasie énergétique. L'augmentation de la masse adipeuse est responsable du développement de dérégulation hormonale qui mène à des dysfonctions physiologiques et métaboliques. Pour contrecarrer le développement démesuré du tissu adipeux, la signalisation insulinique ainsi que l’apport énergétique, responsables de la différenciation adipocytaire, doivent être inhibés. In vivo, la leptine, adipokine dont la concentration est corrélée à la masse adipeuse, présente des actions pro ou anti-insuliniques dans l’organisme pour réguler ce phénomène. Elle favorise l’effet inhibiteur de l’insuline sur la synthèse hépatique de glucose alors qu’elle s’oppose à son action sur l’expression des enzymes glucokinase et phosphoénol-pyruvate carboxykinase. La leptine influence aussi le taux circulant de triglycérides en diminuant sa concentration plasmatique. D'autre part, l'adiponectine, adipokine insulino- sensibilisante, voit sa sécrétion diminuée avec la prise de poids. La sensibilité à l'insuline est ainsi diminuée au fur et à mesure que le débalancement de ces deux adipokines s'accentue. La résistance à l'insuline s'installe alors pour s'opposer au stockage énergétique et à la prise illimitée de poids et la glycémie augmente. L'augmentation du glucose sanguin stimule la sécrétion d'insuline au niveau des cellules pancréatiques. C'est le diabète caractérisé par une hyperglycémie et une résistance à l'insuline. Le diabète, une des premières causes de mortalité dans le monde, est plus répandu sous sa forme non insulinodépendante (diabète de type 2, DT2) liée à l'obésité. Récemment, différents facteurs de transcription ont été identifiés comme régulateurs de l'expression d'une panoplie de gènes impliqués dans le métabolisme glucidique et lipidique. Parmi eux, les récepteurs des inducteurs de la prolifération des peroxysomes (PPAR, Peroxisome Proliferator-Activated Receptor), appartenant à la famille des récepteurs nucléaires. Les PPAR ont été démontrés comme ayant un rôle central dans le contrôle de la transcription des gènes codants pour des protéines impliquées dans le métabolisme : les adipokines. PPARg, en plus de son implication dans le contrôle de l'homéostasie glucidique et lipidique, est reconnu comme étant un facteur de transcription pivot régulant l'adipogenèse du fait de son expression majeure dans le tissu adipeux. D'autre part, il est bien établi maintenant que l'obésité et le diabète sont des facteurs contribuant au développement du processus inflammatoire vasculaire caractéristique de l’athérosclérose. En effet, les cellules endothéliales et musculaires lisses, principales composantes de la média de l’artère, sont très sensibles aux altérations métaboliques. Une diminution de la sensibilité à l’insuline entraine une réduction de la disponibilité du glucose et l’utilisation des acides gras comme alternatif par ces cellules. Ceci induit l’accumulation des acides gras oxydés dans l’intima et leur filtration dans la média pour former un core lipidique. Bien que l’induction de la dysfonction endothéliale soit impliquée très précocement, certaines études pointent l’accumulation lipidique dans les cellules musculaires lisses vasculaires (CML) et leur dysfonction comme déclencheurs de l’athérosclérose. Ce travail visait donc, dans un premier temps, à développer un modèle d'altérations métaboliques liées à la modulation de l'activité du tissu adipeux via une alimentation riche en lipides. Dans un second temps, cette étude tentait d'évaluer l’impact des adipocytes de souris sur les CML vasculaires et sur la modulation de leurs fonctions dans ce modèle d'altérations métaboliques et DT2 liés à l'alimentation et à l'obésité. Ainsi, par le biais de deux diètes pauvres en cholestérol à profil lipidique différent, nous avons développé un modèle murin présentant divers stades d'altérations du métabolisme allant jusqu'au DT2 en lien avec l'obésité chez les mâles et chez les femelles. D’autre part, des signes de cardiomyopathie ainsi qu’une modulation du taux des adipokines sont reliés à ces mêmes diètes. Parallèlement, l’activité de PPAR!2 est modulée chez les souris sous diètes enrichies en gras. Ensuite, nous avons démontré que les adipocytes, provenant de souris alimentées avec une diète enrichie en gras, modulaient la migration et la prolifération des CML comparativement au groupe contrôle. Ces modulations dépendaient en grande partie de la nature de la diète consommée, mais également du sexe de la souris. Par ailleurs, les altérations fonctionnelles des CML, couplées à des modulations géniques, sont associées aux changements du profil de sécrétion des adipokines mesurées chez les adipocytes. L’ensemble de ces travaux suggère une action directe de la nature de la stimulation du tissu adipeux blanc dans la modulation du profil de sécrétion des adipokines et l'induction du DT2 in vivo. Ces altérations de la physiologie adipocytaire se reflètent in vitro où le tissu adipeux contribue aux altérations physiopathologiques des CML liées au DT2. Ainsi, cette étude est l'une des premières à établir un lien direct entre les modulations adipocytaires et les effets de leurs sécrétions sur la physiologie des CML. Ces observations peuvent être exploitées cliniquement dans un développement futur d’outils thérapeutiques visant à prévenir et à traiter les troubles métaboliques et le DT2, en ciblant le tissu adipeux comme entité métabolique et endocrine. / Obesity is recognized as a risk factor to a variety of chronic diseases linked to the metabolic syndrome like atherosclerosis and type 2 diabetes (T2D), and is a major cause of increased risk of morbidity and mortality worldwide. High fat diets (HFD) coupled with sedentarity in the industrialized societies contribute to the raise of metabolic alterations prevalence specifically linked to endocrine troubles. Treatment of these latter should include the comprehension of the molecular mechanisms underlying these disorders in order to appropriately target factors responsible for the disease establishment. Adipose tissue is no longer considered as a passive organ which only stores lipids, but also works as an active gland that secretes several bioactive substances called adipokines. Among them, there are key factors known to play a pivotal role in the regulation of glucose and lipid homeostasis, lipid storage, adipogenesis. They are also recognized for their control of a wide range of cell type like adipocytes, hepatocytes and skeletal myocytes. Accumulation of adipose tissue in obesity, linked with the type as much as the amount of dietary lipids, is due to hyperplasia and hypertrophy of adipocytes. These changes are associated with modification in their secretion and inflammatory profile. To counteract excessive fat tissue development, insulin signalling known for its role in adipogenesis is inhibited. Thus, leptin is secreted by adipocytes to inhibit insulin action and the insulin sensitizer adipokine, adiponectin, is down regulated. The two factors are correlated to weight gain and their respective secretion profile is upregulated for leptin and down regulated for adiponectin. Insulin resistance is developed to prevent energetic storage and unlimited weight gain but glycemic control fails and glycaemia raises. Hyperglycaemia stimulates more insulin secretion, a characteristic of T2D linked to obesity. An estimated 80% of those who develop T2D are obese. Obesity induces important and complex changes, not only in glycemic homeostasis but also in the adipocytes. Following fatty acids (FA) stimulation, the main ligand-activated transcriptional factor that controls adipose tissue metabolism and adipokine secretion, peroxisome proliferator-activated receptor gamma (PPARg), is activated. This nuclear receptor subtype regroups two isoforms: PPARg1, expressed in many tissues (adipose tissue, muscle, heart and liver) where it controls glucose and lipid homeostasis, and PPARg2, the adipocyte’s specific form, which further governs preadipocyte differentiation, up-regulation of genes involved in lipogenesis and the expression of adipokines. Recent advances showed that increased FA and glycaemia trigger vascular alterations that lead to atherosclerosis. In fact, endothelial cells (EC) and smooth muscle cells (SMC), the main arterial components, are sensitive to metabolic alterations. A lack in insulin sensitivity, leading to lower glucose availability, forces arterial cells to use FA as alternative energy source. Thus, in atheroprone regions susceptible to plaque formation, EC and SMC are subjected to metabolic modifications that lead to oxidized low-density lipoprotein (oxLDL) accumulation in the intima and the progression of vascular disease. Many studies confirmed that the presence of SMC in the atherosclerotic plaque originates from the vascular wall but are showing a distinct phenotype. Even if the role of these cells in atherogenesis is not clear, trans-differentiation of SMC into foam cells has been reported in vitro. Thus, the present study aims at studying a HFD-induced obesity mouse model, developed to evaluate the impact of FA nature on the adipokine secretion profile of adipocytes. We also intended to determine gender-specific impact on modulation of metabolic disorders in response to those diets. On the other hand, we aim to determine the role of adipocytes in the development of obesity-linked atherosclerosis. For that, the second part of this study targeted the effect of adipocytes isolated from mice fed with HFD on SMC physiology. We focused our investigation on the effects of adipocytes regardless of the impact of other cell types in the adipose tissue. To reach our goal, we developed a HFD-fed mouse preparation demonstrating different stages of metabolic disorders leading to T2D. This model allowed us to generate adipocytes with different alteration status, reflected by the modulation of their adipokine secretion profile. Modifications in adipokine secretions were associated with PPAR!2 modulation. These results, reported in both genders, were delayed in female who expressed higher levels of estrogen receptor alpha (ER"). Then, the adipocytes were used to produce conditioned cultured media. To decipher the mechanistic contributions of HFD in adipokines modulation, the potential of adipocytes to induce SMC pathophysiologic disorders was evaluated in SMC stimulated by conditioned cultured media. This protocol enables the transposition of diet-induced fat cell modifications into extended alterations in the physiology of vascular SMC. These results strongly support pro-atherogenic effects of abdominal adipocytes on an important vascular component function through paracrine actions. Thus, adipocytes can be recognized as a link between the pathogenic potential of obesity and the impairments of SMC functions. A better understanding of the pathogenic effects of the adipose tissue on other tissues and organ systems might assist to develop better strategies in treating obesity- induced cardiovascular disease and metabolic syndrome.

L’athérosclérose est étroitement liée au diabète de type 2. De fortes concentrations plasmatiques en acides gras libres (AGL) et en insuline sont des caractéristiques retrouvées chez les patients souffrant de ces deux pathologies. Les AGL, présents dans notre alimentation, font partie de l’environnement auquel les cellules sont exposées. Leurs effets dépendent de leur nature, les acides gras saturés (AGS) étant néfastes et les acides gras monoinsaturés (AGMI) plus protecteurs. Ils ont donc des effets variés sur les cellules musculaires lisses vasculaires (CMLV) impliquées dans la pathogénèse de l’athérosclérose. Ainsi, l’objectif principal de ce projet de maîtrise était d’évaluer l’impact de deux combinaisons d’AGL sur la viabilité des CMLV, en condition hyperinsulinémique ou non. Les deux combinaisons renfermaient les mêmes AGL mais en proportions différentes, l’une étant plus riche en AGS et l’autre en AGMI. Nos résultats ont montré que les combinaisons d’AGL ont un effet pro-apoptotique principalement dû aux AGS. L’acide oléique présent dans les combinaisons atténue cependant cet effet. Il diminue même plus fortement l’apoptose des CMLV lorsqu’associé à un AGS que lorsqu’utilisé seul. Cet impact est significatif uniquement dans certaines proportions de ces AGL et est plus efficace en présence d’insuline. Ces résultats mettent en lumière la présence d’une compétition entre mécanismes anti- et pro-apoptotiques en fonction des proportions d’AGS versus AGMI et de l’insulinémie chez les CMLV. Ils soulignent également l’importance de la présence des AGMI dans les diètes riches en AGS et pourraient être utiles pour l’élaboration de nouvelles diètes adaptées aux patients athérosclérotiques et diabétiques. / Atherosclerosis is closely linked to type 2 diabetes. High plasmatic concentrations of free fatty acids (FFA) and insulin are common features in patients suffering from both diseases. FFA, present in our diet, are part of the environment to which body cells are exposed. Their effects are dependent of their nature, being harmful for saturated fatty acids (SFA) and more protective for monounsaturated fatty acids (MUFA). They can have therefore various effects on vascular smooth muscle cells (VSMC) implicated throughout the development of atherosclerosis. Thus, this study aimed to assess the impact of two FFA combinations on VSMC viability, whether or not in a hyperinsulinemic condition. Both combinations contained the same FFA but in different proportions, one being richer in SFA and the other in MUFA. Our results showed that FFA combinations have a pro-apoptotic impact, mainly due to SFA. However, the presence of oleic acid in the combinations attenuated this effect. Furthermore, oleic acid had the capacity to reduce more strongly VSMC apoptosis when combined with a SFA than when used alone, although only under specific FFA ratios. This impact is even more effective in presence of insulin. These results highlight the presence of a competition between anti- and pro-apoptotic mechanisms dependent of FFA ratios (SFA vs. MUFA) and insulinemia to which are exposed VSMC. They also underline the importance of the presence of MUFA such as oleic acid in diets rich in SFA and could be useful for the development of new diets adapted to atherosclerotic and diabetic patients.