| 1. |
- Aavik, Einari, et al.
(författare)
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Global DNA methylation analysis of human atherosclerotic plaques reveals extensive genomic hypomethylation and reactivation at imprinted locus 14q32 involving induction of a miRNA cluster
- 2015
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Ingår i: European Heart Journal. - : Oxford University Press (OUP). - 0195-668X .- 1522-9645. ; 36:16, s. 993-U23
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Tidskriftsartikel (refereegranskat)abstract
- Aims Genetics can explain just above 10% of the observed heritability in cardiovascular diseases. Epigenetics is about to provide some further explanations, but the information needed for that is in the accumulation phase. Genome-wide DNA methylation analysis has revealed thousands of genes, which are epigenetically differentially regulated in atherosclerotic plaques. Our results point to an additional level of complexity that needs to be integrated into the aetiology of atherogenesis.We conducted a genome-wide analysis to identify differentially methylated genes in atherosclerotic lesions. Methods DNA methylation at promoters, exons and introns was identified by massive parallel sequencing. Gene expression was analysed by microarrays, qPCR, immunohistochemistry and western blots. Results Globally, hypomethylation of chromosomal DNA predominates in atherosclerotic plaques and two-thirds of genes showing over 2.5-fold differential in DNA methylation are up-regulated in comparison to healthy mammary arteries. The imprinted chromatin locus 14q32 was identified for the first time as an extensively hypomethylated area in atherosclerosis with highly induced expression of miR127, -136, -410, -431, -432, -433 and capillary formation-associated gene RTL1. The top 100 list of hypomethylated promoters exhibited over 1000-fold enrichment for miRNAs, many of which mapped to locus 14q32. Unexpectedly, also gene body hypermethylation was found to correlate with stimulated mRNA expression. Conclusion Significant changes in genomic methylation were identified in atherosclerotic lesions. The most prominent gene cluster activated via hypomethylation was detected at imprinted chromosomal locus 14q32 with several clustered miRNAs that were up-regulated. These results suggest that epigenetic changes are involved in atherogenesis and may offer new potential therapeutic targets for vascular diseases.
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| 2. |
- Bräsen, Jan Hinrich, et al.
(författare)
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Extracellular superoxide dismutase accelerates endothelial recovery and inhibits in-stent restenosis in stented atherosclerotic Watanabe heritable hyperlipidemic rabbit aorta
- 2007
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Ingår i: Journal of the American College of Cardiology. - : Elsevier BV. - 0735-1097 .- 1558-3597. ; 50:23, s. 2249-2253
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Tidskriftsartikel (refereegranskat)abstract
- This study examined whether local gene therapy with extracellular superoxide dismutase (EC-SOD) could inhibit in-stent restenosis in atherosclerotic Watanabe heritable hyperlipidemic rabbits. Background Stenting causes an acute increase in superoxide anion production and oxidative stress; EC-SOD is a major component of antioxidative defense in blood vessels and has powerful cardioprotective effects in ischemic myocardium. Methods Endothelial denudation and stenting were done in 36 adult (15 to 18 months old) rabbits. Catheter-mediated intramural delivery of clinical good manufacturing practice-grade adenoviruses encoding rabbit EC-SOD were done simultaneously with stenting. Control animals received adenovirus-encoding nuclear-targeted β-galactosidase (AdLacZ). Circulating markers for oxidative stress (nonesterified 8-iso-prostaglandin F2 alpha) were measured. Analysis of 6-day, 28-day, and 90-day vessel histology, radical production, oxidation-specific epitopes, and expression studies were performed. Results The EC-SOD treatment reduced oxidant production in stented vessels compared with control vessels. Early systemic recovery of total SOD activity was observed in the treated rabbits. The EC-SOD significantly accelerated endothelial recovery (67.4% ± 10.8% vs. 24.2.1% ± 4.6% at 6 days, p < 0.05; 89.3% ± 3.7% vs. 45.1% ± 9.6% at 28 days, p < 0.05), and the beneficial effect involved increased proliferation of regenerating endothelium. The EC-SOD group showed a 61.3% lower (p < 0.05) neointimal formation at 28 days, with a similar, albeit nonsignificant trend at 90 days (1.20 ± 0.32 mm2 vs. 1.88 ± 0.24 mm2, p = 0.06). Conclusions The results suggest a central pathogenetic role of oxidation sensitive signaling processes in endothelial recovery and developing in-stent restenosis in atherosclerotic vessels. Local therapy against oxidative stress represents a promising therapeutic strategy in stent-induced vascular injury. Extracellular Superoxide Dismutase Accelerates Endothelial Recovery and Inhibits In-Stent Restenosis in Stented Atherosclerotic Watanabe Heritable Hyperlipidemic Rabbit Aorta Jan Hinrich Bräsen, Olli Leppänen, Matias Inkala, Tommi Heikura, Max Levin, Fabian Ahrens, Juha Rutanen, Hubertus Pietsch, David Bergqvist, Anna-Liisa Levonen, Samar Basu, Thomas Zeller, Günter Klöppel, Mikko O. Laukkanen, Seppo Ylä-Herttuala Percutaneous coronary interventions induce oxidative stress in vessels that already have compromised antioxidative defenses. Extracellular superoxide dismutase (EC-SOD) is a major antioxidant in healthy arteries, and exogenous EC-SOD confers powerful vasculoprotective and cardioprotective effects. However, the effects of EC-SOD therapy on stent-induced vascular injury have not been assessed. We present evidence showing that local therapy with EC-SOD, delivered using clinical-grade adenoviruses, attenuated tissue oxidant production, suppressed developing in-stent restenosis, and accelerated endothelial recovery.
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| 3. |
- Caglayan, Evren, et al.
(författare)
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Disruption of Platelet-Derived Growth Factor-Dependent Phosphatidylinositol 3-Kinase and Phospholipase C gamma 1 Activity Abolishes Vascular Smooth Muscle Cell Proliferation and Migration and Attenuates Neointima Formation In Vivo
- 2011
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Ingår i: Journal of the American College of Cardiology. - : Elsevier BV. - 0735-1097 .- 1558-3597. ; 57:25, s. 2527-2538
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: We tested the hypothesis whether selective blunting of platelet-derived growth factor (PDGF)-dependent vascular smooth muscle cell (VSMC) proliferation and migration is sufficient to prevent neointima formation after vascular injury. BACKGROUND: To prevent neointima formation and stent thrombosis after coronary interventions, it is essential to inhibit VSMC proliferation and migration without harming endothelial cell function. The role of PDGF-a potent mitogen and chemoattractant for VSMC that does not affect endothelial cells-for neointima formation remains controversial. METHODS: To decipher the signaling pathways that control PDGF beta receptor (βPDGFR)-driven VSMC proliferation and migration, we characterized 2 panels of chimeric CSF1R/βPDGFR mutants in which the binding sites for βPDGFR-associated signaling molecules (Src, phosphatidylinositol 3-kinase [PI3K], GTPase activating protein of ras, SHP-2, phospholipase Cγ 1 [PLCγ]) were individually mutated. Based on in vitro results, the importance of PDGF-initiated signals for neointima formation was investigated in genetically modified mice. RESULTS: Our results indicate that the chemotactic response to PDGF requires the activation of Src, PI3K, and PLCγ, whereas PDGF-dependent cell cycle progression is exclusively mediated by PI3K and PLCγ. These 2 signaling molecules contribute to signal relay of the βPDGFR by differentially regulating cyclin D1 and p27(kip1). Blunting of βPDGFR-induced PI3K and PLCγ signaling by a combination mutant (F3) completely abolished the mitogenic and chemotactic response to PDGF. Disruption of PDGF-dependent PI3K and PLCγ signaling in mice expressing the F3 receptor led to a profound reduction of neointima formation after balloon injury. CONCLUSIONS: Signaling by the activated βPDGFR, particularly through PI3K and PLCγ, is crucial for neointima formation after vascular injury. Disruption of these specific signaling pathways is sufficient to attenuate pathogenic processes such as vascular remodeling in vivo.
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| 4. |
- Hellberg, Anders, et al.
(författare)
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Monitoring of intrathecal oxygen tension during experimental aortic occlusion predicts ultrastructural changes in the spinal cord
- 2001
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Ingår i: Journal of Thoracic and Cardiovascular Surgery. - : Elsevier BV. - 0022-5223 .- 1097-685X. ; 121:2, s. 316-323
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To study the correlation between intrathecal PO2 and ultrastructural changes in the spinal cord during thoracic aortic occlusion in pigs. MATERIAL AND METHODS: In 18 pigs, online intrathecal oxygenation was monitored by a multiparameter Paratrend catheter (Biomedical Sensors, High Wycombe, United Kingdom) during 60 minutes' clamping of the proximal and distal descending thoracic aorta. The animals were randomly divided into 2 groups (A and B) depending on the level of distal aortic clamping. Distal aortic perfusion was restored through an aorto-iliac shunt, which also maintained low thoracic segmental perfusion of the spinal cord in group B. Perfusion-fixation technique was used before harvesting the spinal cord specimens, which later were evaluated with light and electron microscopy by an independent observer. Intrathecal parameters were interpreted as normal if PO2 was more than 0.8 kPa and PCO2 was less than 12 kPa, as intermediate ischemia if PO2 was 0.8 or less or PCO (2) was more than 12 kPa, and as absolute ischemia if PO2 was 0.8 or less and PCO2 was more than 12 kPa. RESULTS: Among 6 animals with ultrastructural changes of absolute spinal cord ischemia-reperfusion injury, 5 also had absolute ischemia according to variables derived by the Paratrend catheter. The 2 methods were in agreement in 3 of 5 animals with intermediate ischemia-reperfusion changes and in 5 of 6 animals with normal findings. The accuracy of cerebrospinal fluid PO2 and PCO2 to predict electron microscopy-verified intermediate or absolute ischemia-reperfusion injury was 94%. CONCLUSIONS: Monitoring of intrathecal PO2 after clamping of the descending aorta correlated with ultrastructural changes in the spinal cord in this pig model.
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| 5. |
- Hytonen, Jarkko P., et al.
(författare)
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Local adventitial anti-angiogenic gene therapy reduces growth of vasa-vasorum and in-stent restenosis in WHHL rabbits
- 2018
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Ingår i: Journal of Molecular and Cellular Cardiology. - : ELSEVIER SCI LTD. - 0022-2828 .- 1095-8584. ; 121, s. 145-154
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Tidskriftsartikel (refereegranskat)abstract
- Background: Antiproliferative drugs in drug eluting stents (DES) are associated with complications due to impaired re-endothelialization. Additionally, adventitial neovascularization has been suggested to contribute to in-stent restenosis (ISR). Since Vascular Endothelial Growth Factors (VEGFs) are the key mediators of angiogenesis, we investigated feasibility and efficacy of local gene therapy for ISR utilizing soluble decoy VEGF receptors to reduce biological activity of adventitial VEGFs.Method: Sixty-nine adult WHHL rabbit aortas were subjected to endothelial denudation. Six weeks later catheter-mediated local intramural infusion of 1.5x10e10 pfu adenoviruses encoding soluble VEGF Receptor-1 (sVEGFR1), sVEGFR2, sVEGFR3 or control LacZ and bare metal stent implantation were performed in the same aortic segment. Marker protein expression was assessed at 6d in LacZ cohort. Immunohistochemistry, morphometrical analyses and angiography were performed at d14, d42 and d90.Results: Transgene expression was localized to adventitia. All decoy receptors reduced the size of vasa-vasorum at 14d, AdsVEGFR2 animals also had reduced density of adventitial vasa-vasorum, whereas AdsVEGFR3 increased the density of vasa-vasorum. At d42, AdsVEGFR1 and AdsVEGFR2 reduced ISR (15.7 +/- 6.9% stenosis, P < 0.01 and 16.5 +/- 2.7%, P < 0.05, respectively) vs. controls (28.3 +/- 7.6%). Moreover, AdsVEGFR-3 treatment led to a non-significant trend in the reduction of adventitial lymphatics at all time points and these animals had significantly more advanced neointimal atherosclerosis at 14d and 42d vs. control animals.Conclusions: Targeting adventitial neovascularization using sVEGFR1 and sVEGFR2 is a novel strategy to reduce ISR. The therapeutic effects dissipate at late follow up following short expression profile of adenoviral vectors. However, inhibition of VEGFR3 signaling accelerates neoatherosclerosis.
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| 6. |
- Hytönen, Jarkko, et al.
(författare)
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Activation of Peroxisome Proliferator-Activated Receptor-δ as Novel Therapeutic Strategy to Prevent In-Stent Restenosis and Stent Thrombosis
- 2016
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Ingår i: Arteriosclerosis, Thrombosis and Vascular Biology. - 1079-5642 .- 1524-4636. ; 36:8, s. 1534-1548
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Tidskriftsartikel (refereegranskat)abstract
- Objective Drug-eluting coronary stents reduce restenosis rate and late lumen loss compared with bare-metal stents; however, drug-eluting coronary stents may delay vascular healing and increase late stent thrombosis. The peroxisome proliferator-activated receptor-delta (PPAR) exhibits actions that could favorably influence outcomes after drug-eluting coronary stents placement. Approach and Results Here, we report that PPAR ligand-coated stents strongly reduce the development of neointima and luminal narrowing in a rabbit model of experimental atherosclerosis. Inhibition of inflammatory gene expression and vascular smooth muscle cell (VSMC) proliferation and migration, prevention of thrombocyte activation and aggregation, and proproliferative effects on endothelial cells were identified as key mechanisms for the prevention of restenosis. Using normal and PPAR-depleted VSMCs, we show that the observed effects of PPAR ligand GW0742 on VSMCs and thrombocytes are PPAR receptor dependent. PPAR ligand treatment induces expression of pyruvate dehydrogenase kinase isozyme 4 and downregulates the glucose transporter 1 in VSMCs, thus impairing the ability of VSMCs to provide the increased energy demands required for growth factor-stimulated proliferation and migration. Conclusions In contrast to commonly used drugs for stent coating, PPAR ligands not only inhibit inflammatory response and proliferation of VSMCs but also prevent thrombocyte activation and support vessel re-endothelialization. Thus, pharmacological PPAR activation could be a promising novel strategy to improve drug-eluting coronary stents outcomes.
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| 7. |
- Hänni, Mari, et al.
(författare)
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Postangioplasty restenosis followed with magnetic resonance imaging in an atherosclerotic rabbit model
- 2012
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Ingår i: International Journal of Biomedical Imaging. - : Hindawi Publishing Corporation. - 1687-4188 .- 1687-4196. ; 2012, s. 747264-
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Tidskriftsartikel (refereegranskat)abstract
- Rationale and Objectives. Testing a quantitative, noninvasive method to assess postangioplasty vessel wall changes in an animal model. Material and Methods. Six New Zealand white rabbits were subjected to atherosclerotic injury, including cholesterol-enriched diet, deendothelialization, and percutaneous transluminal angioplasty (PTA) in the distal part of abdominal aorta (four weeks after deendothelialization). The animals were examined with a 1.5T MRI scanner at three times as follows: baseline (six weeks after diet start and two days after PTA) and four weeks and 10 weeks after-PTA. Inflow angiosequence (M2DI) and proton-density-weighted sequence (PDW) were performed to examine the aorta with axial slices. To identify the inner and outer vessel wall boundaries, a dynamic contour algorithm (Gradient Vector Flow Snakes) was applied to the images, followed by calculation of the vessel wall dimensions. The results were compared with histopathological analysis. Results. The wall thickness in the lesion was significantly higher than in the control region at 4 and 10 weeks, reflecting induction of experimentally created after-angioplasty lesion. At baseline, no significant difference between the two regions was present. Conclusions. It is possible to follow the development of vessel wall changes after-PTA with MRI in this rabbit model.
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| 8. |
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| 9. |
- Kappert, Kai, et al.
(författare)
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Antioxidants relieve phosphatase inhibition and reduce PDGF signaling in cultured VSMCs and in restenosis
- 2006
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Ingår i: Arteriosclerosis, Thrombosis and Vascular Biology. - 1079-5642 .- 1524-4636. ; 26:12, s. 2644-2651
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Tidskriftsartikel (refereegranskat)abstract
- Objective - Growth factor- and reactive oxygen species (ROS)-induced activation of VSMCs is involved in vascular disease. This study investigates whether inhibitory oxidation of protein tyrosine phosphatases (PTPs) contributes to signaling in VSMCs in vitro and in vivo, and analyzes whether ROS- and growth factor-dependent vascular smooth muscle cell (VSMC) signaling is blunted by antioxidants that are able to activate oxidized PTPs. Methods and Results - Signaling induced by H2O2 and platelet-derived growth factor (PDGF) was analyzed in VSMCs with or without the antioxidants N-acetyl-cysteine (NAC) and tempol. Effects of antioxidants on PDGF-stimulated chemotaxis and proliferation were determined. In vivo effects of antioxidants were analyzed in the rat carotid balloon-injury model, by analyzing neointima formation, cell proliferation, PDGF beta-receptor status, and PTP expression and activity. NAC treatment prevented H2O2-induced PTP inhibition, and reduced H2O2-and ligand-induced PDGF beta-receptor phosphorylation, PDGF-induced proliferation, and chemotaxis of VSMCs. Antioxidants inhibited neointima formation and reduced PDGF receptor phosphorylation in the neointima and also increased PTP activity. Conclusion - PTP-inhibition was identified as an intrinsic component of H2O2-and PDGF-induced signaling in cultured VSMCs. The reduction in PDGF beta-receptor phosphorylation in vivo, and the increase in PTP activity, by antioxidants indicate activation of oxidized PTPs as a previously unrecognized mechanism for the antirestenotic effects of antioxidants. The findings thus suggest, in general terms, reactivation of oxidized PTPs as a novel antirestenotic strategy.
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| 10. |
- Kappert, Kai, et al.
(författare)
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Dynamic changes in the expression of DEP-1 and other PDGF receptor-antagonizing PTPs during onset and termination of neointima formation
- 2007
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Ingår i: The FASEB Journal. - : Wiley. - 0892-6638 .- 1530-6860. ; 21:2, s. 523-534
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Tidskriftsartikel (refereegranskat)abstract
- Growth factor-dependent tissue remodeling, such as restenosis, is believed to be predominantly regulated by changes in expression of receptor-tyrosine-kinases (RTKs) and their ligands. As endogenous antagonists of RTKs, protein-tyrosine-phosphatases (PTPs) are additional candidate regulators of these processes. Using laser-capture-microdissection and quantitative RT-polymerase chain reaction (qRT-PCR), we investigated the layer-specific expression of the four platelet-derived growth factor (PDGF) isoforms, the PDGF-alpha and beta receptors, and five PTPs implied in control of PDGF-receptor signaling 8 and 14 days after balloon injury of the rat carotid. Results were correlated with analyses of PDGF-beta receptor phosphorylation and vascular smooth muscle cell (VSMC) proliferation in vivo. The expression levels of all components, as well as receptor activation and VSMC proliferation, showed specific changes, which varied between media and neointima. Interestingly, PTP expression--particularly, DEP-1 levels--appeared to be the dominating factor determining receptor-phosphorylation and VSMC proliferation. In support of these findings, cultured DEP-1(-/-) cells displayed increased PDGF-dependent cell signaling. Hyperactivation of PDGF-induced signaling was also observed after siRNA-down-regulation of DEP-1 in VSMCs. The results indicate a previously unrecognized role of PDGF-receptor-targeting PTPs in controlling neointima formation. In more general terms, the observations indicate transcriptional regulation of PTPs as an important mechanism for controlling onset and termination of RTK-dependent tissue remodeling.
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