The vascular system delivers oxygen and nutrients through the entire body. In addition, it enables distribution of hormones and immune cells. A proper functioning vascular system is important in... Show moreThe vascular system delivers oxygen and nutrients through the entire body. In addition, it enables distribution of hormones and immune cells. A proper functioning vascular system is important in preventing cardiovascular disease (CVD). In recent years, several risk factors, e.g. smoking and obesity, have been described. Also genetic variants have been shown to influence vascular function and thereby the risk on developing CVD.In this thesis the role of Neuroimmune Guidance Cues (NGCs) in the development of atherosclerosis, one of the main causes of CVD is investigated. The development of atherosclerosis is characterized by the deposition of fatty acids and immune cells in the vessel wall. With several experiments we have shown that NGCs play an important role in the vessel wall and regulate atherosclerosis-related processes. We show that PLXNA4 regulates endothelial permeability, while the Eph receptor B2 regulates migration of monocytes through the vessel. In addition, we have shown that genetic variants in Eph receptor B4, EphrinB2 and Netrin-1 can modulate atherosclerosis-related processes and thereby could influence the development of CVD.The results shown here give us new insights in the function of the vascular system and provide novel targets to treat and/or prevent CVD. Show less
This thesis details our studies assessing the role of the endothelial-enriched miRNA-126 in the regulation of vascular homeostasis. In Chapter 2 the current insight in the role of miRNA-126 in... Show moreThis thesis details our studies assessing the role of the endothelial-enriched miRNA-126 in the regulation of vascular homeostasis. In Chapter 2 the current insight in the role of miRNA-126 in vascular homeostasis is reviewed. Chapter 3 focuses on the role of miRNA-126 in ischemia induced angiogenesis, followed by Chapter 4 which describes the potential role of miRNA-126 the mobilization of vasculogenic progenitor cells upon ischemia. Both chapters utilize antagomir-technology to specifically silence miRNA-126 in vivo. This approach to silence miRNA-126 was also used in Chapter 5 to elucidate the regulatory role of miRNA-126 in vascular cell adhesion molecule-1 expression in the kidney vasculature. Chapter 6 details our findings that circulating miRNA-126 in the periphery is not exclusively derived from endothelial cells but can also originate from platelets. Consequently, the use of aspirin has to be taken into account when relating circulating miRNA-126 levels to the progression of cardiovascular disease. Chapter 7 demonstrates that the angiogenic potential of miRNA-126 as described in Chapter 3 might reach beyond the presence of this pro-angiogenic miRNA in endothelium, but that neovascularization can also be supported by miRNA-126 expressed in circulating cells. Finally, Chapter 8 provides a summary of research presented in this thesis, presents the major conclusions that could be drawn and further discusses the role of miRNA-126 in vascular homeostasis. Show less
With the use of combinatorial phage display, solid phase peptide synthesis and a multidiscipline of molecular and cellular assays in vascular biology, the research described in this thesis has... Show moreWith the use of combinatorial phage display, solid phase peptide synthesis and a multidiscipline of molecular and cellular assays in vascular biology, the research described in this thesis has resulted in the identification of two novel peptides targeting to SR-AI and CD40 respectively which hold promise as targeted contrast agents for the diagnosis of atherosclerosis symptom. In addition, a peptide named VIVIT and its derivatives had been discovered and synthesized which constitute a more selective and less toxic drug candidate than currently used immunosuppressant cyclosporine A or FK506, leading to new generation immunosuppressants and therapeutics for autoimmune diseases such as rheumatoid arthritis or allograft transplantation and cardiovascular disorders including atherosclerosis, restenosis and cardiac hypertrophy. Show less
Postnatally, Endothelial Progenitor Cells are needed to maintain the integrity of the endothelium (re-endothelialization) and to augment wound healing or vascularize hypoxic areas ... Show morePostnatally, Endothelial Progenitor Cells are needed to maintain the integrity of the endothelium (re-endothelialization) and to augment wound healing or vascularize hypoxic areas (neovascularization). Complex networks of different signals and regulators have been identified to be involved in these processes, but exact mechanisms are not completely understood. Unraveling these complex systems however would be beneficial for treatment of vascular disease. In this thesis we focus on different aspects of EPC biology. We look at the nature of these progenitor cells in a normal environment but we also look at the possible role of EPC in the pathogenesis of vascular disease in patients with Diabetes Mellitus. In both a hyperglycemic mouse model and diabetes patients we observe a reduction in circulating numbers of EPC that showed a significant inverse correlation with glycemic control. Not only did we see less EPC, we also found dysfunction of these EPC. We focus further on this dysfunction and describe mechanisms possibly involved as well as drug treatments to (partially) overcome these unfavorable effects of hyperglycemia on EPC. Eventually, we hope that these new insights in EPC dysfunction may contribute to new treatment strategies or even prevention strategies for the treatment of vascular disease in Diabetes patients. Show less
