Cardiovascular diseases are the major cause of morbidity and mortality in western societies. The most common clinical manifestations are stroke and acute myocardial infarction and in both ailments... Show moreCardiovascular diseases are the major cause of morbidity and mortality in western societies. The most common clinical manifestations are stroke and acute myocardial infarction and in both ailments atherosclerosis is the underlying culprit. Atherosclerosis is a lipid-mediated chronic inflammatory disease, which is accompanied by leukocyte infiltration into the vessel wall. The migration of leukocytes from the circulation to the vessel wall is directed by a specific class of proteins, the chemokines. Therefore it is likely that chemokines have a distinctive role in leukocyte homeostasis at specific stages of atherosclerotic disease progression and during ischemia-reperfusion injury. This thesis encompasses of number of human and experimental mouse studies on the role of chemokines in cardiovascular diseases and atherosclerosis, from which several new targets were identified. For instance it is evident that patients with high levels of the chemokine CCL3 are 10 times more likely to develop severe cardiovascular events in the future. In conclusion, the research described in this thesis provided novel candidates that might be of value for the early prediction of high risk patients. Moreover, the identified candidates may also represent valuable targets for modulation of leukocyte homeostasis in the plaque that could improve atherosclerotic plaque progression and stability. Show less
Hart- en vaatziekten zijn, ondanks de toepassing van cholesterol verlagende medicijnen, nog steeds de meest voorkomende doodsoorzaak in de westerse wereld, en manifesteren zich onder andere door... Show moreHart- en vaatziekten zijn, ondanks de toepassing van cholesterol verlagende medicijnen, nog steeds de meest voorkomende doodsoorzaak in de westerse wereld, en manifesteren zich onder andere door hartinfarcten en hersenbloedingen. Cholesterol, en ook fosfolipiden zijn essentieel voor de opbouw van celmembranen, maar ook voor de synthese van bijvoorbeeld hormonen. Een evenwichtige cholesterol huishouding is dus niet alleen belangrijk voor het hele lichaam maar ook voor individuele cellen. Dit evenwicht wordt, in een gezonde situatie, in stand gehouden door een strak gereguleerde balans tussen de opname van cholesterol uit het voedsel en de novo cholesterol synthese. Het zogenaamde goede cholesterol, het HDL, dankt zijn beschermende werking aan het zogenaamde reverse cholesterol transport, het transport van cholesterol uit de periferie naar de lever, waar het kan worden verwerkt en afgevoerd via de gal naar de feaces. Dit proefschrift richt zich op de verschillende stappen van het reverse cholesterol transport. Concluderend: therapeutische modulatie van het __reverse cholesterol transport__ moet zich niet richten op __n specifiek gen/eiwit, maar er dient gestreefd te worden naar een simultane activatie van cholesterol transporteiwitten wat zou kunnen leiden tot een optimale bescherming tegen vaatvernauwing en dientengevolge hart- en vaatziekten. Show less
Blood-flow-induced shear stress plays an important role in cardiovascular development and disease. How endothelial cells sense shear stress remains to be elucidated. We postulated that the primary... Show moreBlood-flow-induced shear stress plays an important role in cardiovascular development and disease. How endothelial cells sense shear stress remains to be elucidated. We postulated that the primary cilium is a component of the endothelial shear sensor. This luminal cell protrusion contains microtubules and is connected to the microtubular cytoskeleton. We identified cilia on endothelial cells of the embryonic heart in areas of low or oscillatory shear stress. This shear-related distribution is reminiscent of the distribution of atherosclerotic lesions in the adult arterial system, as lesions develop at sites of low or oscillating shear (athero-prone flow). Ciliated endothelial cells are exclusively present at these atherosclerotic predilection sites in adult mice. Athero-prone (oscillatory) but not athero-protective (steady or pulsatile) flow induces ciliation of cultured endothelial cells. Moreover, the endothelial shear response is dependent on the microtubular cytoskeleton and primary cilia sensitise the endothelium for shear. Taken together, these data demonstrate that primary cilia are induced by athero-prone flow and that ciliated cells are more sensitive to shear stress. We conclude that the endothelial biosensor for shear stress is the microtubular cytoskeleton and that the attached primary cilium functions as a signal amplifier in areas subjected to athero-prone flow. Show less
