http://repub.eur.nl/res/aut/36683/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/37351/ 2012-10-01T00:00:00Z Aims/hypothesis: In adults, circulating inflammatory mediators and activated CD14++monocytes link obesity to its metabolic and cardiovascular complications. However, it is largely unknown whether these inflammatory changes already occur in childhood obesity. To survey inflammatory changes during the early stages of obesity, we performed a comprehensive analysis of circulating inflammatory mediators, monocyte populations and their function in childhood obesity. Methods: In lean and obese children aged 6 to 16 years (n∈=∈96), 35 circulating inflammatory mediators including adipokines were measured. Hierarchical cluster analysis of the inflammatory mediator profiles was performed to investigate associations between inflammatory mediator clusters and clinical variables. Whole-blood monocyte phenotyping and functional testing with the toll-like receptor 4 ligand, lipopolysaccharide, were also executed. Results: First, next to leptin, the circulating mediators chemerin, tissue inhibitor of metalloproteinase 1, EGF and TNF receptor 2 were identified as novel inflammatory mediators that are increased in childhood obesity. Second, cluster analysis of the circulating mediators distinguished two obesity clusters, two leanness clusters and one mixed cluster. All clusters showed distinct inflammatory mediator profiles, together with differences in insulin sensitivity and other clinical variables. Third, childhood obesity was associated with increased CD14++monocyte numbers and an activated phenotype of the CD14++monocyte subsets. Conclusions/interpretation: Inflammatory mediator clusters were associated with insulin resistance in obese and lean children. The activation of CD14++monocyte subsets, which is associated with increased development of atherosclerosis in obese adults, was also readily detected in obese children. Our results indicate that inflammatory mechanisms linking obesity to its metabolic and cardiovascular complications are already activated in childhood obesity. http://repub.eur.nl/res/pub/26681/ 2011-07-01T00:00:00Z Plaque rupture and subsequent thrombotic occlusion of the coronary arteryaccount for as many as three quarters of myocardial infarctions. Theconcept of plaque stabilisation emerged about 20 years ago to explainthe discrepancy between the reduction of cardiovascular events in patientsreceiving lipid lowering therapy and the small decrease seen in angiographicevaluation of atherosclerosis. Since then, the concept of a vulnerableplaque has received a lot of attention in basic and clinical researchleading to a better understanding of the pathophysiology of thevulnerable plaque and acute coronary syndromes. From pathological andclinical observations, plaques that have recently ruptured have thin fibrouscaps, large lipid cores, exhibit outward remodelling and invasion byvasa vasorum. Ruptured plaques are also focally inflamed and this maybe a common denominator of the other pathological features. Plaqueswith similar characteristics, but which have not yet ruptured, are believ ed to be vulnerable to rupture. Experimental studies strongly support thevalidity of anti-inflammatory approaches to promote plaque stability. Unfortunately,reliable non-invasive methods for imaging and detection ofsuch plaques are not yet readily available. There is a strong biologicalbasis and supportive clinical evidence that low-density lipoprotein loweringwith statins is useful for the stabilisation of vulnerable plaques. Thereis also some clinical evidence for the usefulness of antiplatelet agents,beta blockers and renin-angiotensin-aldosterone system inhibitors forplaque stabilisation. Determining the causes of plaque rupture and designingdiagnostics and interventions to prevent them are urgent prioritiesfor current basic and clinical research in cardiovascular area. http://repub.eur.nl/res/pub/28353/ 2010-05-01T00:00:00Z Objectives: Cryoplasty combines conventional angioplasty - percutaneous transluminal angioplasty (PTA) - with cold thermal energy. In this animal study, we investigated if preventive cryoplasty could reduce intimal hyperplasia (IH) at the venous anastomosis. Design: We investigated cryoplasty versus PTA of the venous anastomosis in a validated porcine, bilateral, arteriovenous graft model. Animals and methods: In 12 pigs, 24 expanded polytetrafluoroethylene (ePTFE) grafts were bilaterally inserted between the common carotid artery and internal jugular vein. Directly after surgery, one venous anastomosis was treated with cryoplasty at -10 °C, the contralateral anastomosis with conventional PTA. At 4 weeks, graft flow was measured, quantitative angiography was performed and grafts with adjacent vessels were excised for histological analysis. Results: Due to a number of thromboses, data for paired analysis were available from eight pigs. Angiographic outflow vein diameter and graft blood flow were not different between treatment groups. Compared with the control group, IH at the venous anastomosis was reduced by 47% (P = 0.21) and intima/media ratio was reduced by 45% (P = 0.07) by cryoplasty. Effects were most profound in those animals that tended to develop most IH. Conclusion: Our results suggest that preventive cryoplasty of the venous anastomosis might help to reduce IH in those cases that develop most profound IH. http://repub.eur.nl/res/pub/28924/ 2008-03-01T00:00:00Z Background: Toll like receptors (TLR) have been recognized for their role in atherosclerotic lesion development and progression. Endogenous TLR ligands that are also expressed in atherosclerotic tissues have been shown to promote atherosclerosis in mice. Since repetitive stimulation of TLR induces an attenuated inflammatory response, we hypothesized that the TLR response is altered during atherosclerosis development, due to chronic exposure to endogenous ligands. Methods and Results: We examined five groups of both ApoE-/- and C57Bl/6 mice aged 5, 10, 15, 25 and 40 weeks. In ApoE-/- mice with advanced stages of atherosclerosis, levels of mRNA encoding TLR2 and TLR4, the endogenous TLR ligands EDA and hsp60 as well as intracellular TLR-regulating mediators, like IRAK-M, were increased. Systemic TLR cell surface expression on circulating monocytes and EDA plasma levels were significantly increased in ApoE-/- mice with advanced atherosclerosis. We also observed that the endogenous TLR ligand EDA was capable of activating the TLR-signaling pathway in white blood cells. During the plaque progression stage however, stimulation of TLR2 and TLR4 in blood samples attenuated MIP-1α and RANTES release in atherosclerotic mice. Conclusion: During atherosclerotic lesion development, TLR2 and TLR4 expression increases in atherosclerotic plaques and on circulating blood cells. However, with advanced stages of atherosclerotic disease, circulating blood cells become less responsive to TLR ligation, which may be due to chronic TLR engagement by endogenous EDA.