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  • Ovid Technologies (Wolters Kluwer Health)  (11)
  • 1
    In: Circulation, Ovid Technologies (Wolters Kluwer Health), Vol. 132, No. suppl_3 ( 2015-11-10)
    Abstract: Introduction: A high-cholesterol diet has been reported to induce vascular deposition of lipids and oxidized LDL cholesterol in macrophages and other cell types in 15 day-old zebrafish larvae. However, results were based on small samples, and little is known about the heterogeneity of effect within and between conditions, the image quantification procedure used, and the influence of dietary energy. We intend to perform large-scale genetic and compound screens for coronary heart disease, and aimed to confirm or refute if zebrafish larvae are a suitable model system. Methods: In total, 940 transgenic zebrafish larvae were fed on one of six diets between 5 and 10 days post-fertilization (dpf), to examine main effects of, and interactions between dietary energy and cholesterol. At 10 dpf, we assessed body length and acquired optical sections of the dorsal aorta and caudal vein using an automated positioning system, fluorescence microscope and CCD camera. Atherogenic traits were quantified using a custom-written image analysis pipeline in Ilastik, CellProfiler and ImageJ, and larvae were used to assess whole body levels of total cholesterol, triglycerides and glucose using enzymatic assays. Associations were adjusted for body length, ether - used to prepare the high-cholesterol diet - and batch. Results: A high-energy diet resulted in elevated triglyceride levels (p=7.8E-3) - especially in the presence of high dietary cholesterol (p-interaction=0.01) - and in more vascular infiltration by lipids (p=1.0E-12), and co-localising lipids and macrophages (p=0.04), independently of dietary cholesterol. A high-cholesterol diet resulted in higher glucose levels (p=2.1E-3), and in more vascular infiltration by lipids (p=0.01), and co-localising lipids and neutrophils (p=0.04), and lipids, neutrophils and macrophages (p=0.01), independently of dietary energy. Qualitative analyses showed that vascular lipid deposits typically contain oxidised LDL cholesterol, and are located at bifurcation sites of the endothelium. Conclusions: Zebrafish larvae represent a promising model system for high-throughput, image-based screens of early-stage atherosclerosis, and dietary energy and cholesterol induce distinct atherogenic traits as early as 10 dpf.
    Type of Medium: Online Resource
    ISSN: 0009-7322 , 1524-4539
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2015
    detail.hit.zdb_id: 1466401-X
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  • 2
    Online Resource
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    Ovid Technologies (Wolters Kluwer Health) ; 2005
    In:  Medicine & Science in Sports & Exercise Vol. 37, No. Supplement ( 2005-05), p. S210-
    In: Medicine & Science in Sports & Exercise, Ovid Technologies (Wolters Kluwer Health), Vol. 37, No. Supplement ( 2005-05), p. S210-
    Type of Medium: Online Resource
    ISSN: 0195-9131
    RVK:
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2005
    detail.hit.zdb_id: 2031167-9
    SSG: 31
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  • 3
    In: Medicine & Science in Sports & Exercise, Ovid Technologies (Wolters Kluwer Health), Vol. 50, No. 4 ( 2018-04), p. 863-873
    Type of Medium: Online Resource
    ISSN: 0195-9131
    RVK:
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2018
    detail.hit.zdb_id: 2031167-9
    SSG: 31
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  • 4
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    Ovid Technologies (Wolters Kluwer Health) ; 2018
    In:  Arteriosclerosis, Thrombosis, and Vascular Biology Vol. 38, No. Suppl_1 ( 2018-05)
    In: Arteriosclerosis, Thrombosis, and Vascular Biology, Ovid Technologies (Wolters Kluwer Health), Vol. 38, No. Suppl_1 ( 2018-05)
    Abstract: Background: Genome-wide association studies have identified hundreds of loci that are robustly associated with circulating lipids, atherosclerosis and coronary artery disease (CAD). In all but a few of these loci the causal genes and mechanisms remain unknown. Small-scale studies suggest that zebrafish larvae represent a promising model system for genetic screens in dyslipidemia, early-stage atherosclerosis and CAD. We expanded the phenotypic pipeline, increased the throughput, and performed a large-scale validation study. Methods: We used a three-tiered approach to validate the zebrafish model system: 1) a dietary intervention to examine the effect of overfeeding and cholesterol supplementation (N=1956); 2) treatment with atorvastatin and ezetimibe (N=835); and 3) a genetic screen for zebrafish orthologues of APOE, APOB and LDLR using a multiplex CRISPR-Cas9 approach (N=330). After imaging of vascular atherogenic traits and body size, whole-body lipid and glucose levels were assessed using enzymatic assays, and CRISPR-Cas9 target sites were sequenced on a MiSeq. Results: Overfeeding and cholesterol supplementation have independent pro-atherogenic effects, including higher LDLc and triglyceride levels, more vascular infiltration by lipids and oxidized LDLc, and more vascular co-localization of lipids with macrophages and neutrophils. Treatment with atorvastatin and ezetimibe can largely prevent this diet-induced pro-atherogenic state, but results in higher glucose levels. Finally, mutations in apoea and apoeb result in higher whole-body LDLc levels; mutations in apobb.1 result in more vascular co-localization of lipids and neutrophils; and mutations in ldlra result in more vascular infiltration by lipids, and in more vascular co-localization of lipids and macrophages. Data from all larvae combined show that atherosclerosis in 10-day-old zebrafish larvae is mainly driven by higher triglyceride levels. Conclusion: Systematic genetic screens in zebrafish larvae will likely help increase our understanding of disease aetiology and identify new targets that can be translated into efficient medication for prevention and treatment.
    Type of Medium: Online Resource
    ISSN: 1079-5642 , 1524-4636
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2018
    detail.hit.zdb_id: 1494427-3
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  • 5
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    Ovid Technologies (Wolters Kluwer Health) ; 2018
    In:  Arteriosclerosis, Thrombosis, and Vascular Biology Vol. 38, No. Suppl_1 ( 2018-05)
    In: Arteriosclerosis, Thrombosis, and Vascular Biology, Ovid Technologies (Wolters Kluwer Health), Vol. 38, No. Suppl_1 ( 2018-05)
    Abstract: Background: High triglyceride levels are an established risk factor for coronary artery disease (CAD). Unpublished results from our proof-of-principle studies show that triglyceride-levels are also associated with atherosclerosis in zebrafish larvae. Identifying and characterizing causal genes for triglyceride levels may yield novel drug targets. In 2013, a meta-analysis of genome-wide association studies identified 37 previously unanticipated loci that are associated with triglyceride levels. We aim to characterize positional candidate genes in these loci using a zebrafish model system. Methods: We prioritized 37 candidate genes for functional-follow up. These genes together have 41 zebrafish orthologues, which were targeted in five lines of ~8 genes each using a multiplex CRISPR-Cas9 approach. Founder mutants have been raised and 384 offspring for two of the five lines have so far been screened for body size as well as fluorescently labeled lipids, macrophages and neutrophils in the vessel wall, using a high-throughput imaging set-up. Image quantification was performed using automated, custom-written pipelines in CellProfiler and ImageJ. Additionally, whole body lipid fractions and glucose levels were measured in each larva using enzymatic assays. CRISPR-induced mutations were quantified using paired-end sequencing and data were analyzed using hierarchical mixed models and (zero-inflated) negative binomial regression. Results: Each additional disrupted allele in pepd resulted in higher triglyceride levels (beta±SE 0.21±0.09 SD). Mutants for met have less vascular infiltration by macrophages (-0.31±0.13), and less co-localization of macrophages with lipids (-0.56±0.21) and neutrophils (-0.49±0.18). Mutants for lpar2 have lower LDLc (-0.54±0.27) and HDLc levels (-0.57±0.27), while gmip mutants have less vascular lipid deposition (-1.05±0.43), and less co-localizing lipids and neutrophils (-1.26±0.56). Conclusion: By characterizing candidate genes for triglyceride levels using a high-throughput, largely image-based approach in zebrafish larvae, we identified previously unanticipated genes that influence a range of cardiometabolic risk factors. This approach is anticipated to identify novel drug targets.
    Type of Medium: Online Resource
    ISSN: 1079-5642 , 1524-4636
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2018
    detail.hit.zdb_id: 1494427-3
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  • 6
    Online Resource
    Online Resource
    Ovid Technologies (Wolters Kluwer Health) ; 2016
    In:  Arteriosclerosis, Thrombosis, and Vascular Biology Vol. 36, No. suppl_1 ( 2016-05)
    In: Arteriosclerosis, Thrombosis, and Vascular Biology, Ovid Technologies (Wolters Kluwer Health), Vol. 36, No. suppl_1 ( 2016-05)
    Abstract: Genome-wide association studies (GWAS) identified 56 loci that are robustly associated with the risk of coronary artery disease (CAD). Only a handful of genes in these loci are currently known to influence CAD. We previously showed that: 1) CAD-associated loci exert their effect at least in part by influencing atherosclerotic plaque formation; 2) zebrafish larvae are a promising model system for high-throughput screens of early-stage atherosclerosis. We now aim to identify causal genes in GWAS-identified loci for CAD using a zebrafish model system. Heterozygous carriers of nonsense (sa1516 in CXCL12 ; fh336 in COL4A1 ) or essential splice site (sa1504 in FLT1 ) mutations were in-crossed, and offspring were fed a normal or high amount of diet from 5 to 10 days post-fertilisation. Vascular lipid deposition was subsequently visualised using a fluorescent dye, automated positioning system, fluorescence microscope and CCD camera, and quantified using a custom-written image analysis pipeline in Ilastik and CellProfiler. After imaging, whole-body total cholesterol, triglyceride and glucose levels were assessed using enzymatic assays, and larvae were genotyped using KASP technology. Multiple linear regression analysis (additive model) was used to examine the effect of each mutation. Mutations in FLT1 and COL4A1 resulted in less vascular lipid deposition in overfed larvae (p=3.6E-2 and p=1.9E-2, respectively), but had no effect in larvae fed on a normal amount (p=0.26, p=0.64). Sa1504 in FLT1 additionally resulted in lower total cholesterol levels (p=3.7E-3) and a trend for lower triglyceride levels (p=0.06), independently of the amount fed. The remaining associations did not reach nominal significance (p 〉 0.05). Our results represent the first mutant models demonstrating that FLT1 and COL4A1 play a role in early-stage atherosclerosis, implying that these genes are the culprits in corresponding GWAS-identified loci. We believe that CXCL12 remains the most promising candidate in 11q11.1, and that the lack of effect in our screen reflects genetic redundancy and/or a late onset effect. We will repeat the screen to confirm or refute the results, and additionally examine if mutations in FLT1 and COL4A1 influence vascular inflammation and foam cell formation.
    Type of Medium: Online Resource
    ISSN: 1079-5642 , 1524-4636
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2016
    detail.hit.zdb_id: 1494427-3
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  • 7
    In: Neurology, Ovid Technologies (Wolters Kluwer Health), Vol. 92, No. 5 ( 2019-01-29)
    Type of Medium: Online Resource
    ISSN: 0028-3878 , 1526-632X
    RVK:
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2019
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  • 8
    In: Neurology, Ovid Technologies (Wolters Kluwer Health), Vol. 92, No. 9 ( 2019-02-26), p. e944-e950
    Type of Medium: Online Resource
    ISSN: 0028-3878
    RVK:
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2019
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  • 9
    Online Resource
    Online Resource
    Ovid Technologies (Wolters Kluwer Health) ; 2005
    In:  Medicine & Science in Sports & Exercise Vol. 37, No. Supplement ( 2005-05), p. S210-
    In: Medicine & Science in Sports & Exercise, Ovid Technologies (Wolters Kluwer Health), Vol. 37, No. Supplement ( 2005-05), p. S210-
    Type of Medium: Online Resource
    ISSN: 0195-9131
    RVK:
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2005
    detail.hit.zdb_id: 2031167-9
    SSG: 31
    Location Call Number Limitation Availability
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  • 10
    Online Resource
    Online Resource
    Ovid Technologies (Wolters Kluwer Health) ; 2015
    In:  Arteriosclerosis, Thrombosis, and Vascular Biology Vol. 35, No. suppl_1 ( 2015-05)
    In: Arteriosclerosis, Thrombosis, and Vascular Biology, Ovid Technologies (Wolters Kluwer Health), Vol. 35, No. suppl_1 ( 2015-05)
    Abstract: Objectives: Published results show that overfeeding zebrafish larvae on a high-cholesterol diet (HCD) can result in hypercholesterolemia and sub-endothelial lipid deposition in macrophages and other cell types. However, results are so far based on small samples, and the atherogenic response has been heterogeneous. We aim to use zebrafish larvae for large-scale, CRISPR-Cas9-based genetic screens, using results from genome wide association studies for coronary heart disease as a starting point. Firstly however, we need to ensure the model system is appropriate and robust. Therefore, we examined the effect of a high-energy diet (HED) and HCD on vascular lipid deposition in a larger number of larvae (n=241). Methods: Starting at 5 days post fertilization (dpf), ~30 larvae/tank were fed 2x/day on: 1) 5 mg control diet (CD; n=33); 2) 15 mg control diet (HED; n=90); or 3) 15 mg control diet enriched with 4% cholesterol (HCD; n=94). At 14-17 dpf, larvae were soaked in monodansylpentane cadaverase - a lipid staining dye - for 45 min, before imaging the dorsal aorta and caudal vein with a Leica SP5 confocal microscope. We used a custom written script in Cell Profiler to quantify the surface area of lipid deposits in the vasculature. Results: Manual annotation of vascular lipid deposition in 30 images (10 randomly selected images per dietary condition) allowed us to calculate the sensitivity (36%) and specificity (71%) of the Cell Profiler script. Subsequent analyses showed that HED (p=0.004) and HCD (p=0.001) fed larvae have significantly more vascular lipid deposition than CD fed larvae after adjusting for age, batch and vessel length. There was no difference in vascular lipid deposition between HED and HCD fed larvae (p=0.11). Discussion and conclusion: Our results confirm that zebrafish larvae represent a promising model system for early-stage atherosclerosis. In addition, they show that enriching the diet with cholesterol is not required to prompt atherogenesis. Future directions: In the next few months, we will examine if overfeeding also triggers vascular infiltration by macrophages, neutrophils and oxidized LDL cholesterol, and if atherogenesis can be prevented or reduced by treating larvae with statins and/or ezetimibe, using our new, automated imaging setup.
    Type of Medium: Online Resource
    ISSN: 1079-5642 , 1524-4636
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2015
    detail.hit.zdb_id: 1494427-3
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