Molekularbiologische und zelltherapeutische Strategien zur Verbesserung der Vaskularisierung transplantierter Langerhans-Inseln

Die Transplantation von Langerhans-Inseln als therapeutischer Ansatz für Typ I Diabetes-Patienten stellt eine vielversprechende Alternative zur täglichen Insulinapplikation dar. Da die transplantierten Langerhans-Inseln allerdings bisher unzureichend revaskularisiert werden und daher ihre endokrine Funktion und ihr Überleben oft nicht dauerhaft garantiert sind, konnte sich diese Therapiemethode bisher nicht in der klinischen Routine durchsetzen. Entsprechend wird bis heute an der Entwicklung neuer Ansätze geforscht, um die Vaskularisierung transplantierter Langerhans-Inseln zu verbessern. Nerve/glial antigen (NG) 2 ist ein Proteoglykan, welches von Perizyten exprimiert wird und an der Regulation der Angiogenese beteiligt ist. Der Einfluss von NG2 auf die Inseltransplantation ist jedoch bis heute nicht bekannt. Daher wurde im ersten Studienabschnitt der vorliegenden Arbeit untersucht, ob NG2 die Revaskularisierung transplantierter Inseln fördert. Dazu wurden die Langerhans-Inseln von NG2+/+-Wildtyp- und NG2-/--Knockout-Mäusen zunächst mittels Immunhistochemie auf ihre zelluläre Zusammensetzung untersucht. Anschließend konnte die endokrine Funktion der isolierten Inseln mittels eines Insulin-Enzym-Immunassays analysiert werden. Zuletzt wurden die NG2+/+- und NG2-/--Inseln auf den quergestreiften Hautmuskel der Rückenhautkammer von NG2+/+-Mäusen transplantiert, um deren Revaskularisierung mittels intravitaler Fluoreszenzmikroskopie sowie immunhistochemischen Methoden untersuchen zu können. Im Rahmen dieser Analysen konnte gezeigt werden, dass sich NG2+/+- und NG2-/--Langerhans-Inseln weder in ihrer zellulären Zusammensetzung noch in ihrer Insulin-Sekretion unterscheiden. NG2-/--Inseln wiesen jedoch im Vergleich zu NG2+/+-Kontrollen eine signifikant reduzierte funktionelle Gefäßdichte sowie eine verringerte Anzahl CD31-positiver Blutgefäße an Tag 10 nach Transplantation auf. Folglich konnte gezeigt werden, dass der Verlust von NG2 die Revaskularisierung transplantierter Langerhans-Inseln beeinträchtigt. Dies verdeutlicht die Bedeutung dieses perizytären Oberflächenproteins für die Inseltransplantation. Im zweiten Studienabschnitt der vorliegenden Arbeit wurde untersucht, ob die Inkorporation von mikrovaskulären Fragmenten (MVF) in Inselorganoide deren Vaskularisierung verbessert. MVF werden aus Fettgewebe gewonnen und wurden bereits als potente Vaskularisierungseinheiten zur Prävaskularisierung von verschiedenen Geweben beschrieben. Bisher fanden sie allerdings noch keine Anwendung in der Inseltransplantation. Um prävaskularisierte Inselorganoide (PI+MVF) zu generieren, wurden Inselzellen und MVF aus C57BL/6N-Spendermäusen isoliert und über 5 Tage mithilfe der Liquid-Overlay-Technik co-kultiviert. Frisch isolierte Langerhans-Inseln, kultivierte Langerhans-Inseln und nicht prävaskularisierte Inselorganoide dienten als Kontrollen. Die Viabilität der Langerhans-Inseln und Inselorganoide wurde anhand von durchflusszytometrischen Analysen und der Verwendung von Spendermäusen, die einen endogenen Wasserstoffperoxid-Sensor exprimieren, bestimmt. Mithilfe von immunhistochemischen Untersuchungen und Western Blot-Analysen wurde die Interaktion zwischen den β- und Endothelzellen innerhalb der PI+MVF verifiziert. Die angiogene Aktivität der PI+MVF wurde in vivo unter Verwendung des murinen Rückenhautkammer-Modells und der repetitiven intravitalen Fluoreszenzmikroskopie sowie immunhistochemischer Methoden analysiert. Abschließend wurden PI+MVF in diabetische Empfängermäuse transplantiert, um die endokrine Funktion der Inselorganoide in vivo nachzuweisen. Im Rahmen dieser Analysen konnte gezeigt werden, dass die parakrine Signalübertragung zwischen β-Zellen und MVF die Viabilität und angiogene Aktivität der PI+MVF verbessert. In vivo wiesen die PI+MVF innerhalb der ersten Tage nach Transplantation eine beschleunigte Vaskularisierung auf, was anhand einer gesteigerten funktionellen Gefäßdichte und einem erhöhten Anteil an CD31-positiven Endothelzellen innerhalb der PI+MVF gezeigt werden konnte. Zudem induzierte die Transplantation von 250 Inselorganoiden in diabetische Mäuse innerhalb von 4 Tagen physiologische Blutglukosespiegel, während die identische Zahl frisch isolierter Langerhans-Inseln über den gesamten Beobachtungszeitraum von 28 Tagen nicht zu einer Normoglykämie führte. Diese Ergebnisse zeigen, dass die Inkorporation von MVF die Vaskularisierung von PI+MVF deutlich verbessert und die Wiederherstellung einer Normoglykämie in diabetischen Mäusen beschleunigt. Der hier vorgestellte Prävaskularisierungsansatz könnte damit eine vielversprechende Strategie sein, um in Zukunft die Erfolgsraten der klinischen Inselzelltransplantation zu erhöhen.Pancreatic islet transplantation is a promising therapeutic approach for the treatment of type 1 diabetic patients. However, this method is not yet established in clinical routine, because it is still limited by failed islet survival and endocrine function due to insufficient islet vascularization. To overcome this problem, current research focuses on strategies to improve the vascularization of transplanted islets. Nerve/glial antigen (NG) 2 is a proteoglycan, which is expressed on pericytes and a crucial regulator of angiogenesis. However, the influence of this proteoglycan on islet transplantation is still unknown. Accordingly, the aim of the first study section of the present thesis was to clarify whether NG2 promotes the revascularization of transplanted pancreatic islets. For this purpose, islets were isolated from NG2+/+ wild-type and NG2-/- knockout mice and analyzed by immunohistochemistry to examine their cellular composition. Their endocrine function was assessed by an insulin-enzyme-linked immunosorbent assay. Moreover, NG2+/+ and NG2-/- islets were transplanted into the dorsal skinfold chamber of NG2+/+ mice to study their revascularization by intravital fluorescence microscopy and immunohistochemistry. It could be shown that NG2+/+ and NG2-/- islets do neither differ in their cellular composition nor in their insulin secretion. However, NG2-/- islets exhibited a significantly reduced functional microvessel density and a lower number of CD31-positive blood vessels on day 10 after transplantation when compared to NG2+/+ controls. These results demonstrate that the loss of NG2 impairs the revascularization of transplanted islets, indicating the importance of this surface protein for successful islet transplantation. In the second study section of the present thesis, it was examined whether the incorporation of microvascular fragments (MVF) in islet organoids improves their vascularization after transplantation. MVF can be isolated from adipose tissue and have already been described as potent vascularization units for the prevascularization of various tissues. However, their impact on the engraftment of transplanted islets has not been analyzed, yet. For the generation of prevascularized islet organoids (PI+MVF), islet cells and MVF were isolated from C57BL/6N donor mice and co-cultured for 5 days by means of the liquid overlay technique. Freshly isolated islets, cultured islets and non-prevascularized islet organoids served as controls. The islets’ and islet organoids’ viability was determined by flow cytometric analysis and donor mice expressing an endogenous hydrogen peroxide sensor. Immunohistochemical studies and Western blot analysis were used to investigate the interaction between β-cells and endothelial cells within PI+MVF. The angiogenic potential of PI+MVF was determined by means of the mouse dorsal skinfold chamber model in combination with repetitive intravital fluorescence microscopy and immunohistochemical methods. Finally, PI+MVF were transplanted into diabetic recipient mice to verify their endocrine function in vivo. It could be shown that the paracrine signal transduction between β-cells and MVF improves the viability and angiogenic activity of PI+MVF. In vivo, PI+MVF exhibited an accelerated vascularization, as demonstrated by an increased functional microvessel density during the entire observation period and an increased fraction of endothelial cells 14 days after transplantation. Moreover, the transplantation of 250 PI+MVF into diabetic mice resulted in physiological blood glucose levels within 4 days, while the identical number of freshly isolated islets did not restore normoglycemia during the entire observation period of 28 days. Taken together, these results demonstrate that the incorporation of MVF significantly improves the vascularization of transplanted PI+MVF and accelerates the restoration of normoglycemia in diabetic mice. Thus, this prevascularization approach may be a promising strategy to increase the success of clinical islet cell transplantation in the future

Human Practice. Digital Ecologies. Our Future. : 14. Internationale Tagung Wirtschaftsinformatik (WI 2019) : Tagungsband

Erschienen bei: universi - Universitätsverlag Siegen. - ISBN: 978-3-96182-063-4Aus dem Inhalt: Track 1: Produktion & Cyber-Physische Systeme Requirements and a Meta Model for Exchanging Additive Manufacturing Capacities Service Systems, Smart Service Systems and Cyber- Physical Systems—What’s the difference? Towards a Unified Terminology Developing an Industrial IoT Platform – Trade-off between Horizontal and Vertical Approaches Machine Learning und Complex Event Processing: Effiziente Echtzeitauswertung am Beispiel Smart Factory Sensor retrofit for a coffee machine as condition monitoring and predictive maintenance use case Stakeholder-Analyse zum Einsatz IIoT-basierter Frischeinformationen in der Lebensmittelindustrie Towards a Framework for Predictive Maintenance Strategies in Mechanical Engineering - A Method-Oriented Literature Analysis Development of a matching platform for the requirement-oriented selection of cyber physical systems for SMEs Track 2: Logistic Analytics An Empirical Study of Customers’ Behavioral Intention to Use Ridepooling Services – An Extension of the Technology Acceptance Model Modeling Delay Propagation and Transmission in Railway Networks What is the impact of company specific adjustments on the acceptance and diffusion of logistic standards? Robust Route Planning in Intermodal Urban Traffic Track 3: Unternehmensmodellierung & Informationssystemgestaltung (Enterprise Modelling & Information Systems Design) Work System Modeling Method with Different Levels of Specificity and Rigor for Different Stakeholder Purposes Resolving Inconsistencies in Declarative Process Models based on Culpability Measurement Strategic Analysis in the Realm of Enterprise Modeling – On the Example of Blockchain-Based Initiatives for the Electricity Sector Zwischenbetriebliche Integration in der Möbelbranche: Konfigurationen und Einflussfaktoren Novices’ Quality Perceptions and the Acceptance of Process Modeling Grammars Entwicklung einer Definition für Social Business Objects (SBO) zur Modellierung von Unternehmensinformationen Designing a Reference Model for Digital Product Configurators Terminology for Evolving Design Artifacts Business Role-Object Specification: A Language for Behavior-aware Structural Modeling of Business Objects Generating Smart Glasses-based Information Systems with BPMN4SGA: A BPMN Extension for Smart Glasses Applications Using Blockchain in Peer-to-Peer Carsharing to Build Trust in the Sharing Economy Testing in Big Data: An Architecture Pattern for a Development Environment for Innovative, Integrated and Robust Applications Track 4: Lern- und Wissensmanagement (e-Learning and Knowledge Management) eGovernment Competences revisited – A Literature Review on necessary Competences in a Digitalized Public Sector Say Hello to Your New Automated Tutor – A Structured Literature Review on Pedagogical Conversational Agents Teaching the Digital Transformation of Business Processes: Design of a Simulation Game for Information Systems Education Conceptualizing Immersion for Individual Learning in Virtual Reality Designing a Flipped Classroom Course – a Process Model The Influence of Risk-Taking on Knowledge Exchange and Combination Gamified Feedback durch Avatare im Mobile Learning Alexa, Can You Help Me Solve That Problem? - Understanding the Value of Smart Personal Assistants as Tutors for Complex Problem Tasks Track 5: Data Science & Business Analytics Matching with Bundle Preferences: Tradeoff between Fairness and Truthfulness Applied image recognition: guidelines for using deep learning models in practice Yield Prognosis for the Agrarian Management of Vineyards using Deep Learning for Object Counting Reading Between the Lines of Qualitative Data – How to Detect Hidden Structure Based on Codes Online Auctions with Dual-Threshold Algorithms: An Experimental Study and Practical Evaluation Design Features of Non-Financial Reward Programs for Online Reviews: Evaluation based on Google Maps Data Topic Embeddings – A New Approach to Classify Very Short Documents Based on Predefined Topics Leveraging Unstructured Image Data for Product Quality Improvement Decision Support for Real Estate Investors: Improving Real Estate Valuation with 3D City Models and Points of Interest Knowledge Discovery from CVs: A Topic Modeling Procedure Online Product Descriptions – Boost for your Sales? 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On the Effectiveness of IT Consumerization Policies Agile and Attached: The Impact of Agile Practices on Agile Team Members’ Affective Organisational Commitment The Complexity Trap – Limits of IT Flexibility for Supporting Organizational Agility in Decentralized Organizations Platform Openness: A Systematic Literature Review and Avenues for Future Research Competence, Fashion and the Case of Blockchain The Digital Platform Otto.de: A Case Study of Growth, Complexity, and Generativity Track 8: eHealth & alternde Gesellschaft Security and Privacy of Personal Health Records in Cloud Computing Environments – An Experimental Exploration of the Impact of Storage Solutions and Data Breaches Patientenintegration durch Pfadsysteme Digitalisierung in der Stressprävention – eine qualitative Interviewstudie zu Nutzenpotenzialen User Dynamics in Mental Health Forums – A Sentiment Analysis Perspective Intent and the Use of Wearables in the Workplace – A Model Development Understanding Patient Pathways in the Context of Integrated Health Care Services - Implications from a Scoping Review Understanding the Habitual Use of Wearable Activity Trackers On the Fit in Fitness Apps: Studying the Interaction of Motivational Affordances and Users’ Goal Orientations in Affecting the Benefits Gained Gamification in Health Behavior Change Support Systems - A Synthesis of Unintended Side Effects Investigating the Influence of Information Incongruity on Trust-Relations within Trilateral Healthcare Settings Track 9: Krisen- und Kontinuitätsmanagement Potentiale von IKT beim Ausfall kritischer Infrastrukturen: Erwartungen, Informationsgewinnung und Mediennutzung der Zivilbevölkerung in Deutschland Fake News Perception in Germany: A Representative Study of People’s Attitudes and Approaches to Counteract Disinformation Analyzing the Potential of Graphical Building Information for Fire Emergency Responses: Findings from a Controlled Experiment Track 10: Human-Computer Interaction Towards a Taxonomy of Platforms for Conversational Agent Design Measuring Service Encounter Satisfaction with Customer Service Chatbots using Sentiment Analysis Self-Tracking and Gamification: Analyzing the Interplay of Motivations, Usage and Motivation Fulfillment Erfolgsfaktoren von Augmented-Reality-Applikationen: Analyse von Nutzerrezensionen mit dem Review-Mining-Verfahren Designing Dynamic Decision Support for Electronic Requirements Negotiations Who is Stressed by Using ICTs? A Qualitative Comparison Analysis with the Big Five Personality Traits to Understand Technostress Walking the Middle Path: How Medium Trade-Off Exposure Leads to Higher Consumer Satisfaction in Recommender Agents Theory-Based Affordances of Utilitarian, Hedonic and Dual-Purposed Technologies: A Literature Review Eliciting Customer Preferences for Shopping Companion Apps: A Service Quality Approach The Role of Early User Participation in Discovering Software – A Case Study from the Context of Smart Glasses The Fluidity of the Self-Concept as a Framework to Explain the Motivation to Play Video Games Heart over Heels? An Empirical Analysis of the Relationship between Emotions and Review Helpfulness for Experience and Credence Goods Track 11: Information Security and Information Privacy Unfolding Concerns about Augmented Reality Technologies: A Qualitative Analysis of User Perceptions To (Psychologically) Own Data is to Protect Data: How Psychological Ownership Determines Protective Behavior in a Work and Private Context Understanding Data Protection Regulations from a Data Management Perspective: A Capability-Based Approach to EU-GDPR On the Difficulties of Incentivizing Online Privacy through Transparency: A Qualitative Survey of the German Health Insurance Market What is Your Selfie Worth? A Field Study on Individuals’ Valuation of Personal Data Justification of Mass Surveillance: A Quantitative Study An Exploratory Study of Risk Perception for Data Disclosure to a Network of Firms Track 12: Umweltinformatik und nachhaltiges Wirtschaften Kommunikationsfäden im Nadelöhr – Fachliche Prozessmodellierung der Nachhaltigkeitskommunikation am Kapitalmarkt Potentiale und Herausforderungen der Materialflusskostenrechnung Computing Incentives for User-Based Relocation in Carsharing Sustainability’s Coming Home: Preliminary Design Principles for the Sustainable Smart District Substitution of hazardous chemical substances using Deep Learning and t-SNE A Hierarchy of DSMLs in Support of Product Life-Cycle Assessment A Survey of Smart Energy Services for Private Households Door-to-Door Mobility Integrators as Keystone Organizations of Smart Ecosystems: Resources and Value Co-Creation – A Literature Review Ein Entscheidungsunterstützungssystem zur ökonomischen Bewertung von Mieterstrom auf Basis der Clusteranalyse Discovering Blockchain for Sustainable Product-Service Systems to enhance the Circular Economy Digitale Rückverfolgbarkeit von Lebensmitteln: Eine verbraucherinformatische Studie Umweltbewusstsein durch audiovisuelles Content Marketing? Eine experimentelle Untersuchung zur Konsumentenbewertung nachhaltiger Smartphones Towards Predictive Energy Management in Information Systems: A Research Proposal A Web Browser-Based Application for Processing and Analyzing Material Flow Models using the MFCA Methodology Track 13: Digital Work - Social, mobile, smart On Conversational Agents in Information Systems Research: Analyzing the Past to Guide Future Work The Potential of Augmented Reality for Improving Occupational First Aid Prevent a Vicious Circle! The Role of Organizational IT-Capability in Attracting IT-affine Applicants Good, Bad, or Both? Conceptualization and Measurement of Ambivalent User Attitudes Towards AI A Case Study on Cross-Hierarchical Communication in Digital Work Environments ‘Show Me Your People Skills’ - Employing CEO Branding for Corporate Reputation Management in Social Media A Multiorganisational Study of the Drivers and Barriers of Enterprise Collaboration Systems-Enabled Change The More the Merrier? The Effect of Size of Core Team Subgroups on Success of Open Source Projects The Impact of Anthropomorphic and Functional Chatbot Design Features in Enterprise Collaboration Systems on User Acceptance Digital Feedback for Digital Work? Affordances and Constraints of a Feedback App at InsurCorp The Effect of Marker-less Augmented Reality on Task and Learning Performance Antecedents for Cyberloafing – A Literature Review Internal Crowd Work as a Source of Empowerment - An Empirical Analysis of the Perception of Employees in a Crowdtesting Project Track 14: Geschäftsmodelle und digitales Unternehmertum Dividing the ICO Jungle: Extracting and Evaluating Design Archetypes Capturing Value from Data: Exploring Factors Influencing Revenue Model Design for Data-Driven Services Understanding the Role of Data for Innovating Business Models: A System Dynamics Perspective Business Model Innovation and Stakeholder: Exploring Mechanisms and Outcomes of Value Creation and Destruction Business Models for Internet of Things Platforms: Empirical Development of a Taxonomy and Archetypes Revitalizing established Industrial Companies: State of the Art and Success Principles of Digital Corporate Incubators When 1+1 is Greater than 2: Concurrence of Additional Digital and Established Business Models within Companies Special Track 1: Student Track Investigating Personalized Price Discrimination of Textile-, Electronics- and General Stores in German Online Retail From Facets to a Universal Definition – An Analysis of IoT Usage in Retail Is the Technostress Creators Inventory Still an Up-To-Date Measurement Instrument? Results of a Large-Scale Interview Study Application of Media Synchronicity Theory to Creative Tasks in Virtual Teams Using the Example of Design Thinking TrustyTweet: An Indicator-based Browser-Plugin to Assist Users in Dealing with Fake News on Twitter Application of Process Mining Techniques to Support Maintenance-Related Objectives How Voice Can Change Customer Satisfaction: A Comparative Analysis between E-Commerce and Voice Commerce Business Process Compliance and Blockchain: How Does the Ethereum Blockchain Address Challenges of Business Process Compliance? 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