Liposomal prednisolone promotes macrophage lipotoxicity in experimental atherosclerosis

Atherosclerosis is a lipid-driven inflammatory disease, for which nanomedicinal interventions are under evaluation. Previously, we showed that liposomal nanoparticles loaded with prednisolone (LN-PLP) accumulated in plaque macrophages, however, induced proatherogenic effects in patients. Here, we confirmed in low-density lipoprotein receptor knockout (LDLr−/−) mice that LN-PLP accumulates in plaque macrophages. Next, we found that LN-PLP infusions at 10 mg/kg for 2 weeks enhanced monocyte recruitment to plaques. In follow up, after 6 weeks of LN-PLP exposure we observed (i) increased macrophage content, (ii) more advanced plaque stages, and (iii) larger necrotic core sizes. Finally, in vitro studies showed that macrophages become lipotoxic after LN-PLP exposure, exemplified by enhanced lipid loading, ER stress and apoptosis. These findings indicate that liposomal prednisolone may paradoxically accelerate atherosclerosis by promoting macrophage lipotoxicity. Hence, future (nanomedicinal) drug development studies are challenged by the multifactorial nature of atherosclerotic inflammation

Translating lipid-driven inflammation in atherosclerosis

The first part of this thesis illustrates the increased inflammatory activity present in multiple compartments in patients with atherosclerosis, visualized with functional imaging. Positron emission tomography with computed tomography (PET/CT) is a nuclear technique that employs radioactive tracers, such as the glucose analogue ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG). Uptake of this tracer marks cellular glucose consumption, and as such, the metabolic need of a cell. Several cell types are known for their high metabolic demands, including proliferative and inflammatory cells. Considering the large number of inflammatory cells in plaques, predominantly macrophages, ¹⁸F-FDG PET/CT is also an attractive strategy in atherosclerosis. In fact, several histological, plaque gene expression and biomarker studies have validated arterial ¹⁸F-FDG uptake as a surrogate for (macrophage-driven) inflammation. Having witnessed the correlations between lipids and inflammation in plaque, plasma and progenitors, the second part of this thesis further investigates the direct impact of atherogenic lipoproteins on inflammation by integrating functional imaging with immunological assays. To summarize the major findings in part II, atherogenic lipids and its associated oxidized phospholipid content directly affect inflammation both at the level of the arterial wall as the circulating cells in the plasma compartment. Considering the increased inflammatory activity in patients, despite standard of care including lipid lowering, the final part of this thesis addresses inflammation as a potential additional target in atherosclerosis. In aggregate, the studies in part III of this thesis illustrate the challenges and opportunities of anti-inflammatory drugs in atherosclerosis, in which nanotechnology might facilitate the pursuit for selective and targeted approaches

Neuroimaging in lissencephaly type I

The CT scan's of 22 patients with lissencephaly type I, a severe developmental disorder of the cerebral cortex, were studied. In 6 patients a magnetic resonance (MR), scan was also performed. The CT and MR scans of the lissencephaly patients were compared to a control group consisting of 49 patients with a normal CT or MR scan. In lissencephaly the cortical thickness was always larger than 10 mm, as compared to less than 7 mm in the normal situation. In lissencephaly the WSF/DSF index (with/depth of the sylvian fissure) was always larger than 0.29, while in the normal situation less than 0.25

Animal studies for the evaluation of in situ tissue-engineered vascular grafts - a systematic review, evidence map, and meta-analysis

Vascular in situ tissue engineering (TE) is an approach that uses bioresorbable grafts to induce endogenous regeneration of damaged blood vessels. The evaluation of newly developed in situ TE vascular grafts heavily relies on animal experiments. However, no standard for in vivo models or study design has been defined, hampering inter-study comparisons and translational efficiency. To provide input for formulating such standard, the goal of this study was to map all animal experiments for vascular in situ TE using off-the-shelf available, resorbable synthetic vascular grafts. A literature search (PubMed, Embase) yielded 15,896 studies, of which 182 studies met the inclusion criteria (n = 5,101 animals). The reports displayed a wide variety of study designs, animal models, and biomaterials. Meta-analysis on graft patency with subgroup analysis for species, age, sex, implantation site, and follow-up time demonstrated model-specific variations. This study identifies possibilities for improved design and reporting of animal experiments to increase translational value

Oxidized Phospholipids on Lipoprotein(a) Elicit Arterial Wall Inflammation and an Inflammatory Monocyte Response in Humans

Contains fulltext : 165726.pdf (publisher's version ) (Closed access)BACKGROUND: Elevated lipoprotein(a) [Lp(a)] is a prevalent, independent cardiovascular risk factor, but the underlying mechanisms responsible for its pathogenicity are poorly defined. Because Lp(a) is the prominent carrier of proinflammatory oxidized phospholipids (OxPLs), part of its atherothrombosis might be mediated through this pathway. METHODS: In vivo imaging techniques including magnetic resonance imaging, (18)F-fluorodeoxyglucose uptake positron emission tomography/computed tomography and single-photon emission computed tomography/computed tomography were used to measure subsequently atherosclerotic burden, arterial wall inflammation, and monocyte trafficking to the arterial wall. Ex vivo analysis of monocytes was performed with fluorescence-activated cell sorter analysis, inflammatory stimulation assays, and transendothelial migration assays. In vitro studies of the pathophysiology of Lp(a) on monocytes were performed with an in vitro model for trained immunity. RESULTS: We show that subjects with elevated Lp(a) (108 mg/dL [50-195 mg/dL]; n=30) have increased arterial inflammation and enhanced peripheral blood mononuclear cells trafficking to the arterial wall compared with subjects with normal Lp(a) (7 mg/dL [2-28 mg/dL]; n=30). In addition, monocytes isolated from subjects with elevated Lp(a) remain in a long-lasting primed state, as evidenced by an increased capacity to transmigrate and produce proinflammatory cytokines on stimulation (n=15). In vitro studies show that Lp(a) contains OxPL and augments the proinflammatory response in monocytes derived from healthy control subjects (n=6). This effect was markedly attenuated by inactivating OxPL on Lp(a) or removing OxPL on apolipoprotein(a). CONCLUSIONS: These findings demonstrate that Lp(a) induces monocyte trafficking to the arterial wall and mediates proinflammatory responses through its OxPL content. These findings provide a novel mechanism by which Lp(a) mediates cardiovascular disease. CLINICAL TRIAL REGISTRATION: URL: http://www.trialregister.nl. Unique identifier: NTR5006 (VIPER Study)

Non-invasive prenatal diagnosis for translocation carriers—YES please or NO go?

Introduction: The presence of an unbalanced familial translocation can be reliably assessed in the cytotrophoblast of chorionic villi. However, carriers of a balanced translocation often decline invasive testing. This study aimed to investigate whether an unbalanced translocation can also be diagnosed in cell free DNA by whole-genome non-invasive prenatal screening (NIPS). Material and methods: Pregnant women carrying a fetus with an unbalanced familial translocation, for whom NIPS as well as microarray data were available, were included in this retrospective assessment. NIPS was performed in the course of the TRIDENT study. Results: In 12 cases, both NIPS and microarray data were available. In 10 of 12 cases the unbalanced translocation was correctly identified by NIPS without prior knowledge on parental translocation. One was missed because the fetal fraction was too low. One was missed because of technical restrictions in calling 16p gains. Conclusions: This study supports the hypothesis that routine NIPS may be used for prenatal diagnosis of unbalanced inheritance of familial translocations, especially with prior knowledge of the translocation allowing focused examination of the involved chromosomal regions. Our study showed that routine shallow sequencing designed for aneuploidy detection in cell free DNA may be sufficient for higher resolution NIPS, if specialized copy number software is used and if sufficient fetal fraction is present.</p