During my PhD we have investigated different approaches to block intraplaque angiogenesis in atherosclerosis. Intraplaque angiogenesis is a physiological response to the increased oxygen demand in... Show moreDuring my PhD we have investigated different approaches to block intraplaque angiogenesis in atherosclerosis. Intraplaque angiogenesis is a physiological response to the increased oxygen demand in the plaque but also has adverse effects by facilitating intraplaque hemorrhage and influx of inflammatory mediators, resulting in plaque instability and consequent rupture. To study this phenomenon we used in vitro assays as well as the accelerated atherosclerosis vein graft model in ApoE3*Leiden mice, a unique model in which the formed plaque shows characteristics that highly resemble human atherosclerotic lesions, including intraplaque angiogenesis and hemorrhage and a high inflammatory cell content. We focused on different approaches to restore plaque stability via improving intraplaque oxygen levels as well as via blocking different growth factors signaling. Moreover we studied the effects of our treatments on the interaction between angiogenesis and inflammation both in vitro and in vivo. Show less
Cardiovascular diseases (CVDs) remain the leading cause of death worldwide, and thus, novel therapies are required. CVDs generally result in local shortages in the blood supply, known as ischemia.... Show moreCardiovascular diseases (CVDs) remain the leading cause of death worldwide, and thus, novel therapies are required. CVDs generally result in local shortages in the blood supply, known as ischemia. Neovascularization is the body's innate response mechanism that stimulates the restoration of blood flow to ischemic tissues. During the last decade, microRNAs have emerged as critical regulators of both CVD and neovascularization. Recent studies demonstrated that microRNAs are altered in many ways; however, whether these microRNA modifications could be physiologically relevant remained unclear. We examined whether specific microRNAs with a known cardiovascular function are subject to particular microRNA-alterations and if they could be relevant in cardiovascular disease. Our experiments demonstrated that the level of specific microRNA alterations, including isomiR formation, adenosine-to-inosine editing, and N6-adenosine methylation, changed in response to cardiovascular pathology. Many of these alterations changed the microRNAs function, which had a direct effect on processes like neovascularization. For example, microRNA adenosine-to-inosine editing increased after ischemia in both mice and humans and promoted neovascularization. These findings suggest that microRNA modifications can potentially be harnessed as a biomarker for cardiovascular disease, or even a novel therapeutic target. Show less
The endothelial glycocalyx (EG) is critically involved in vascular integrity and homeostasis, where it regulates endothelial cell mechanotransduction, vascular permeability, coagulation and... Show moreThe endothelial glycocalyx (EG) is critically involved in vascular integrity and homeostasis, where it regulates endothelial cell mechanotransduction, vascular permeability, coagulation and inflammation. Loss of the glomerular EG component, hyaluronan, results in albuminuria and vascular destabilisation. Glomerular loss of hyaluronan has a profound effect on endothelial stability, and similar effects were observed in tumor vessels of metastatic melanomas and in muscular tissue of diabetic patients with critical limb ischemia. Endothelial hyaluronan biosynthesis is critically determined by the endothelial metabolic state which glycolysis is a determining factor of endothelial hyaluronan biosynthesis and function. Show less
In this thesis, we will utilize embryonic zebrafish tumour models to understand the interaction between engrafted human cancer cells and macrophages from the host, test drug administration... Show moreIn this thesis, we will utilize embryonic zebrafish tumour models to understand the interaction between engrafted human cancer cells and macrophages from the host, test drug administration modalities and anti-cancer efficacies of newly-developed PDT and PACT compounds, and test a light-triggered liposomal system for targeted drug delivery specifically to cancer cells in vivo. In chapter 2, we investigate the role of macrophages in tumour-induced angiogenesis. We show that macrophage-dependent angiogenesis is driven by macrophage recruitment to lactic acid secreted by glycolytic B16 melanoma cells. Chemical inhibition of macrophages and glycolysis blocks the initiation of angiogenesis in these models, suggesting that macrophages attracted to glycolytic melanoma cells contribute to the tumour-induced angiogenesis process.In chapters 3 and 4, we explore novel PDT and PACT compounds, respectively, for treatment of conjunctival melanoma in zebrafish. We inject conjunctival melanoma cells into the retro-orbital site to establish an orthotopic model and into the Duct of Cuvier to generate an ectopic model. Our results prove that zebrafish provides a fast vertebrate cancer model to test the optimal administration regimen of drugs, conditions of light irradiation, host toxicity and anti-cancer efficacy of PDT and PACT drugs against conjunctival melanoma.In chapter 5, we focus on modifying liposomes to be light triggered in order to deliver drugs specifically to cancer cells. We inject MDA231 breast cancer cells into the Duct of Cuvier at 2 days post fertilization (dpf) to initiate metastasis to the CHT. We successfully demonstrate that light-triggered, cell-specific delivery of liposome-encapsulated doxorubicin reduces the xenograft cancer cell burden without enhanced cytotoxicity of the zebrafish embryos. In chapter 6, we summarize the novel anti-cancer strategies, which we have developed using zebrafish xenograft models. In the same chapter, we frame our findings in the current scientific landscape and discuss future perspectives. Show less
Despite the available treatment options and sophisticated imaging technologies for monitoring lesion development, the morbidity and mortality from acute cardiovascular events remain unacceptably... Show moreDespite the available treatment options and sophisticated imaging technologies for monitoring lesion development, the morbidity and mortality from acute cardiovascular events remain unacceptably high.While cholesterol-lowering, anti-inflammatory and anti-platelet therapies benefits can increase survival as a primary or secondary prevention, they are not sufficient for plaque rupture prevention. Moreover, the most advance imaging technologies to detect high-risk atherosclerotic patients fail to visualize and explore cellular events in small preclinical models. Therefore, there is a clear need for the development of new therapies and the application of high-resolution imaging modalities.In the current thesis, we evaluated new possibilities to inhibit and image intraplaque angiogenesis. Show less
