The umbilical cord and cord blood contain stem cells that can be used for regenerative cell therapies such as hematopoietic stem cell transplantation. However, the application of cord blood is... Show moreThe umbilical cord and cord blood contain stem cells that can be used for regenerative cell therapies such as hematopoietic stem cell transplantation. However, the application of cord blood is hindered by the slow engraftment of the cells and delayed immune reconstitution compared to stem cells of other sources such as bone marrow. This thesis focuses on ways to improve CB application from both the perspective of the patient (i.e. better engraftment) as well as from the cost perspective (i.e. wider applicability). To this aim, we investigated (combinations of) methods for the improvement of CB engraftment in a murine engraftment model for human hematopoietic cells. Besides our focus on the PB recovery of platelets and CD45+ cells, we furthermore looked at practical aspects of the application of CB such as the possibility of banking expanded cells, banking CB for other purposes than HST and the use of other extra-fetal (embryonic) tissues such as the umbilical cord. Show less
Hematopoietic stem cell transplantation (HSCT) and mesenchymal stromal (MSC) cell therapy are currently under investigation as novel therapies for inflammatory bowel diseases (IBD). Hematopoietic... Show moreHematopoietic stem cell transplantation (HSCT) and mesenchymal stromal (MSC) cell therapy are currently under investigation as novel therapies for inflammatory bowel diseases (IBD). Hematopoietic stem cells are thought to repopulate the immune system and reset the immunological response to luminal antigens. MSCs have the capacity to differentiate into a wide variety of distinct cell lineages and to suppress immune responses in vitro and in vivo. The main goal of this thesis was to study the safety, feasibility, and applicability of stem cell therapy in IBD. Chapter 2 concludes that autologous HSCT appears to be safe and can be an alternative strategy for Crohn__s disease patients with severe and therapy resistant disease. Data from the phase I study described in Chapter 3 demonstrates that MSCs isolated from Crohn__s disease patients have similar characteristics compared to MSCs from healthy donors and that administration of autologous bone marrow derived MSCs appears to be safe and feasible in the treatment of refractory Crohn__s disease. Chapter 4 shows that MSC phenotype and function are not affected by therapeutic concentrations of drugs commonly used in the treatment of IBD. Chapter 5 demonstrates that IFN-_ activation of MSCs increases their immunosuppresive capacities and importantly, their therapeutic efficacy in vivo. Show less
De resultaten beschreven in dit proefschrift verschaffen nieuwe inzichten in verschillende aspecten van de behandeling van inflammatoire darmziekten. Uit grote studies is gebleken dat mutaties in... Show moreDe resultaten beschreven in dit proefschrift verschaffen nieuwe inzichten in verschillende aspecten van de behandeling van inflammatoire darmziekten. Uit grote studies is gebleken dat mutaties in genen die betrokken zijn bij het autofagie proces (autophagos: __zelf-eten__), geassocieerd zijn met de ziekte van Crohn. In dit proefschrift wordt beschreven hoe deze mutatie in dendritische cellen leidt tot hyperactivatie van het immuunsysteem. Dit mechanisme kan mogelijk een nieuw aangrijpingspunt verschaffen voor nieuwe therapie voor pati_nten die een mutatie hebben in dit gen. Anti-tumor-necrosis-factor-alpha (anti-TNF_) therapie neemt een steeds belangrijkere plaats in in de behandeling van IBD; het werkingsmechanisme is echter niet geheel duidelijk. In dit proefschrift wordt beschreven hoe regulatoire macrophagen met immuunsuppressieve en wondgenezende eigenschappen ge_nduceerd worden door anti-TNF_ therapie. Dit werkingsmechanisme kan nieuwe aangrijpingspunten verschaffen voor toekomstige therapie_n. Tevens wordt in dit proefschrift een experimentele behandeling van Crohn met mesenchymale stamcellen (MSCs) beschreven. Deze behandeling is haalbaar en veilig gebleken, hetgeen aanleiding geeft tot verder onderzoek naar de effectiviteit van MSCs in de behandeling van Crohn. Tot slot werd het v__rkomen van kwaadaardige lymfomen onderzocht in IBD pati_nten in Nederland. Deze lymfomen bleken niet vaker voor te komen in de totale groep IBD pati_nten vergeleken met gezonde mensen, wel werd een verhoogde incidentie gezien in bepaalde leeftijdsgroepen. Daarnaast bleek het ontstaan van een EBV positief lymfoom (epstein Barr virus) sterk geassocieerd te zijn met het gebruik van azathioprine, een ander immuunsuppressieve therapie. Samenvattend beschrijft dit proefschrift verschillende aspecten van IBD therapie, en worden nieuwe inzichten en aangrijpinspunten verschaft Show less
Stem cell therapy has raised enthusiasm as a potential treatment for cardiovascular diseases. However, questions remain about the in vivo behavior of the cells after transplantation and the... Show moreStem cell therapy has raised enthusiasm as a potential treatment for cardiovascular diseases. However, questions remain about the in vivo behavior of the cells after transplantation and the mechanism of action with which the cells could potentially alleviate disease symptoms. The objective of the research as described in this thesis was to visualize survival, proliferation, and migration of embryonic (ESC) and adult stem cells using non-invasive molecular imaging techniques in small animal models of cardiovascular diseases. The major findings can be described as follows: (1) Non-invasive bioluminescence imaging is a validated tool to monitor donor cell survival, proliferation, migration, and misbehavior; (2) ESC are a potential source for true regenerative therapy; (3) ESC form teratomas; (4) Adult stem cell survival is short-lived, but of all cells currently used in the clinic, mononuclear cells show the most prolonged survival; (5) Transplantation of mononuclear cells can preserve cardiac function in the short term after myocardial infarction in mice; (6) Compared to other measurements of murine cardiac function, Micro-CT is a superior method to assess cardiac geometry and function; and (7) Transplantation of mononuclear cells in peripheral artery disease is hampered by dismal cell survival and homing. These findings illustrate the current challenges for optimizing stem cell therapy for cardiovascular disease. Show less
Embryonic EPDCs are crucial for proper myocardial architecture and coronary vessel formation, both through their physical contribution and their regulatory role in these developmental processes.... Show moreEmbryonic EPDCs are crucial for proper myocardial architecture and coronary vessel formation, both through their physical contribution and their regulatory role in these developmental processes. This thesis reports for the first time on the role of Epicardium-Derived Cells (EPDCs) in the adult ischemic heart. It is demonstrated that transplanted adult EPDCs, isolated from human adult epicardial tissue, improve left ventricular function of the ischemic mouse heart. This is probably instigated by an early paracrine-mediated stimulation of the injected EPDCs on the surrounding host tissue, as indicated by increased wall thickness, augmented vascular density (mouse origin), and enhanced DNA-damage repair activity of the endogenous tissue. Cardiac healing in the EPDC-recipients is further characterized by advanced WT-1 expression, a marker for undifferentiated EPDCs, indicating induction of endogenous epicardial activity. Strikingly, the benefit of EPDC injection can be further enhanced by adding complementary cardiomyocyte progenitor cells to the EPDC transplant, explained by synergistic paracrine actions of the two different cell types. Two different techniques for assessment of left ventricular function in the post-infarct failing mouse heart are evaluated. It is shown that both conductance catheter and magnetic resonance imaging are reliable methods, each having specific unique features which need to be considered during experimental set-up. Show less
