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Insulin signaling determines anabolic energy uptake processes into brown fat during catabolic conditions of adaptive thermogenesis
Abstracts / Atherosclerosis 263 (2017) e1ee28
Conclusions: Polyunsaturated lipid species of HDL, primarily PA(36:4), PA(38:4), PA(38:5), PA(38:6), PG(36:2), LPC(18:2), PE(34:2) and PE(38:6), are most strongly affected by genetic apoA-I deficiency. WORKSHOP 1.4 Immunometabolism: the interface of immune and metabolic responses in disease W1.4:3. IMPAIRED FATTY ACID SYNTHESIS AFFECTS IMMUNE CELLS ACTIVATION: FOCUS ON STEROL REGULATORY ELEMENT BINDING FACTOR-1C ON T LYMPHOCYTES Fabrizia Bonacina1, Gaia Cermenati1, Donatella Caruso1, Alberico Luigi Catapano1, 2, Nico Mitro1, Giuseppe Danilo Norata1, 3, 4. 1 Department of Pharmacological and Biomolecular Sciences University of Milan, Milan, Italy; 2 IRCSS Multimedica, Milan, Italy; 3 Centro SISA per lo studio dell aterosclerosi, Ospedale Bassini, Milan, Italy; 4 William Harvey Research Institute Barts and The London School of Medicine & Dentistry Queen Mary University, London, United Kingdom Aim: Intracellular metabolism has recently recognized as a key determinant of immune cells differentiation and activation; whereas activated T cells relay on glycolysis, naïve, memory and regulatory Tcells use fatty acids oxidation(FAO) for their metabolic demand. We investigated how key proteins regulating intracellular fatty acid (FA) metabolism (SREBP1c) affected the polarization of CD4Tcells Methods: A detailed immunophenotyping through flow cytometry and metabolic profiling of isolated Tregulatory(CD4+CD25+) and Tconventional(CD4+CD25-) cells was performed in SREBP1cKO and WT littermates Results: SREBP1c deficiency resulted in a significant reduction of T cells fueled by FAO: CD4+CD44+ (18.48±1.03% vs 22.85±0.54%, p<0,01), CD8+CD44+ (11.63±0.82% vs 14.86±1.24%,p<0,05), and Tregulatory CD4+CD25hiFoxP3+ cells (2.61±0.25% vs 3.38±0.10%, p<0,01). To unrevail the role of FA in Tcells, metabolomic analysis was performed on isolated cells. SREBP1cKO Treg showed a reduction of FA synthesis with accumulation of acetilCoA(2.73±0.3vs4.52±0.59 ng/mgprotein,p<0,01) which led to an accumulation of medium-chain acetylcarnitines (C8: 3.8 ±0.6 vs 6.2±0.07; C10 :2.4±0.04 vs 4.6±0.05; C14: 1.02±0.1 vs 1.8±0.2,pg/mgprotein,p<0,01), suggesting an incomplete FAO; glycolisis was also affected with accumulation of lactate(13.47±2.53 vs 36.25±7.48,ng/mgprotein, p<0,01) in Treg of SREBP1cKO. This phenotype was peculiar of Treg as metabolites of Tconv were similar between SREBP1cKO and WT, thus addressing a key role of FA metabolism in Treg but not other CD4Tcells. Conclusions: Treg may relay on a “futile” cycle by producing and burning FA. SREBP1c represents a key player of FA metabolism and its deficiency affects Treg metabolism leading to reduced levels of these cells. Therefore, reprogramming Tcell FA metabolism may represent a therapeutic target for dysregulations of immune activation.
W1.4:2. CLEC4E SIGNALING PROMOTES PRO-ATHEROGENIC MACROPHAGE RESPONSES ment1, Gemma Basatemur1, Leanne Masters1, Lauren Marc Cle Baker1, Patrick Bruneval2, Taka Iwawaki3, Manfred Kneilling4, Sho Yamasaki3, Jane Goodall1, Ziad Mallat5. 1 University of Cambridge, e et de la Cambridge, United Kingdom; 2 Institut National de la Sant Recherche M edicale, Paris, France; 3 Kyushu University, Kyushu, Japan; 4 Eberhard Karls University, Tübingen, Germany; 5 Inserm U970Department of Cardiovascular research, Paris, France Aim: Tuberculosis granulomas share similar features with arterial atherosclerotic plaques. The presence of a necrotic core and the accumulation of lipid promote progression towards an unstable atherosclerotic lesion. Clec4e (Mincle) receptor mediates macrophage activation in response to mycobacterial glycolipid, but also senses damaged cells and drives inflammatory activation in response to necrotic cell death. Our aims were to examine the role of Clec4e in atherosclerosis development and identify the signaling pathways that mediate macrophage responses to Clec4e stimulation
e23
Methods: Male 6-8 week old Ldlr–/– mice were lethally irradiated then reconstituted with bone marrow cells from donor wildtype or Clec4e deficient mice. Mice were fed a high fat diet and atherosclerosis development examined at 20 weeks. In vitro experiments utilized bone marrow-derived macrophages and peritoneal macrophages derived from gene targeted mice deficient in Clec4e or defective in ER stress signaling pathways (CHOP, IRE-1 and ATF3). Results: Clec4e deletion in vivo substantially reduced macrophage inflammation, proliferation and foam cell formation in response to hypercholesterolemia, and significantly limited atherosclerosis. In vitro experiments revealed that Clec4e signaling induced a Syk-mediated ER stress response, leading to the induction of pro-inflammatory mediators (e.g., Tnf, Il6, Ccl2) and growth factors (e.g., Csf1), and inhibition of cholesterol efflux. Chop and Ire1 deficiencies significantly limited Clec4e-dependent effects, whereas Atf3 deficiency promoted both Clec4e expression and downstream inflammatory responses. Conclusions: Our results identify a non-redundant role for Clec4e in coordinating major pathways involved in advanced atherosclerosis and suggest that it may play similar roles in orchestrating granuloma formation
W1.4:3. INHIBITION OF GLYCOLYSIS REDUCES INTRAPLAQUE ANGIOGENESIS IN A MOUSE MODEL OF ADVANCED ATHEROSCLEROSIS Bieke Van Der Veken, Guido De Meyer, Wim Martinet. Laboratory of Physiopharmacology, University of Antwerp, Antwerp, Belgium Aim: Intraplaque (IP) neovascularization is a critical factor in atherosclerotic plaque rupture. Recent studies in cancer research have demonstrated that proliferating endothelial cells generate up to 85% of their ATP from glycolysis. Because 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) plays a critical role in glycolysis, we investigated whether PFKFB3 inhibition affects IP neovascularization and plaque stability in ApoE-/- mice containing a heterozygous mutation in the fibrillin-1 gene Fbn1C1039G, a model of advanced atherosclerosis with IP neovascularization. Methods: ApoE-/- Fbn1C1039G+/- mice were fed a western diet (WD). PFKFB3 inhibitor 3-(3-pyridinyl)-1-(4-pyridinyl)-2-propen-1-one (3PO, 50 mg/g, i.p.) or solvent was administered starting either after 4 weeks WD (2x/week, 10 weeks, preventive regimen) or after 16 weeks WD (4x/week, 4 weeks, curative regimen). Results: 3PO reduced IP neovascularization and haemorrhages by 50% (preventive regimen) and 38% (curative regimen). This compound had no effect on smooth muscle cell content in the plaques (preventive: 7±1% vs. 7±1% in control; curative: 9±1% vs. 8±1% in control). Similarly, the collagen deposition in the plaques was not affected (preventive: 16±4% vs. 16±1% in control; curative: 25±1% vs. 26±2% in control). However, 3PO tended to decrease the macrophage content (preventive: 8±2% vs. 14±4%; curative: 5±1% vs. 7±1%). Plasma VEGF-A levels decreased significantly (curative: 838±449 vs. 2871±653 pg/ml, p¼0.027) and cardiac function improved after 10 weeks of treatment (fractional shortening 31±4% vs. 23±3%, p¼0.013; LVIDd 4.6±0.2mm vs. 4.0±1mm, p¼0.032, LVIDs 3.7±0.1mm vs. 2.8±0.3mm, p¼0.009). Conclusions: Inhibition of PFKFB3 by 3PO significantly represses IP angiogenesis and haemorrhages in mice, demonstrating its potential in preventing plaque rupture. WORKSHOP 2.4 Regulators of metabolism and cardiometabolic disease W2.4:1. INSULIN SIGNALING DETERMINES ANABOLIC ENERGY UPTAKE PROCESSES INTO BROWN FAT DURING CATABOLIC CONDITIONS OF ADAPTIVE THERMOGENESIS Fischer1, Renate Schreiber2, Rudolf Markus Heine1, Alexander € rg Heeren1. 1 University Medical Center Zechner2, Ludger Scheja1, Jo Hamburg-Eppendorf, Hamburg, Germany; 2 University of Graz, Graz, Austria
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Abstracts / Atherosclerosis 263 (2017) e1ee28
Aim: Catabolic, cold activated brown adipose tissue burns triglycerides for heat production. Consequently, endogenous lipid stores need to be replenished by anabolic processes including fatty acid uptake by active adipocytes. The aim of this study was to investigate the catabolic and anabolic processes in lipid handling of activated BAT.
lower MTTP expression in cardiomyocytes. In mice, MTTP-A deficient mice displayed impaired heart function after an experimental myocardial infarction.
W2.4:3. MITOCHONDRIAL ACTIVITY IS A MAJOR CONTRIBUTOR TO THE PROINFLAMMATORY CAPACITY OF MICROVESICLES Florian Puhm1,2, Taras Afonyushkin2, Georg Obermayer2, Christoph Binder2. 1 Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria; 2 Research Center for Molecular Medicine (CeMM) of the Austrian Academy of Sciences, Vienna, Austria
ĂMethods: BAT activity was stimulated by cold exposure or CL316,243 (CL) treatment in wildtype and transgenic mice. The uptake processes were investigated by metabolic turnover studies intravital microscopy and magnetic resonance imaging after injection of nanoparticle labelled TRL. Results: Increased BAT activity is accompanied by enhanced insulin secretion. CL treatment stimulated anabolic processes in BAT via insulin dependent phosphorylation of Akt kinase. This process is dependent on CD36 and is associated with facilitated whole particle uptake. Inhibition of insulin secretion using the potassium channel agonist diazoxide or impairing insulin signalling with insulin receptor blocking during activation abolished TRL uptake into BAT. Conclusions: Our data show that cold promotes catabolic as well as anabolic processes in BAT whereas insulin orchestrates metabolic pathways that controls lipoprotein handling for the replenishment of endogenous energy stores. Impaired lipoprotein processing mediated by BAT in insulin resistant states could lead to dyslipidemia observed in patients suffering from type 2 diabetes mellitus.
W2.4:2. MICROSOMAL TRIGLYCERIDE TRANSFER PROTEIN IN THE ISCHEMIC HEART ang1, Marcus Ståhlman1, Ewa Martina Klevstig1, Margareta Scharin T€ n1. 1 The Wallenberg Laboratory, Ehrenborg2, Malin C. Levin1, Jan Bore Institute of Medicine, Department of Molecular and Clinical Medicine, University of Gothenburg, Gothenburg, Sweden; 2 Atherosclerosis Research Unit, Department of Medicine, Center for Molecular Medicine, Karolinska Institute, Stockholm, Sweden Aim: Myocardial ischemia is associated with cardiac dysfunction and lipid accumulation. However, the underlying molecular(s) are still poorly understood. The microsomal triglyceride transfer protein (MTTP), which is critical for hepatic lipoprotein assembly and secretion, is also expressed in cardiomyocytes. The aim of this study was to assess the relationship between the MTTP and cardiac function after a myocardial infarction. Methods: Patients with suspected coronary artery disease (n¼310) underwent echocardiography and myocardial perfusion scintigraphy examinations, and were genotyped for the MTTP polymorphism rs1800804. The cardiac MTTP expression was examined in 126 biopsies from the left ventricle of patients undergoing elective heart surgery. Heart function in MTTP-A heart-specific knockout mice were analyzed using echocardiography at baseline and after myocardial infarction. Results: Subjects with the minor rs1800804 C-allele had lower MTTP expression and significantly lower stress systolic tissue velocity as well as higher infarct and wall motion scores compared with non-carriers. The minor allele of the MTTP polymorphism rs3816873 (known as Ile128Thr), which is in complete allelic association with rs1800804, was significantly (P¼0.001) associated with lower expression of MTTP in cardiomyocytes. In mice, MTTP-A deficiency did not affect the baseline heart function but displayed significantly smaller ejection fraction and stroke volume 24h after myocardial infarction, compare to littermates controls. Conclusions: The MTTP rs1800804 polymorphism showed significant associations with structural and perfusion abnormalities reflecting myocardial infarction and stress-induced cardiac dysfunction along with
Aim: Microvesicles (MVs) are recognized as promoters of inflammation and increased numbers of MVs have been described in cardiovascular diseases. Because mitochondrial content has been shown to be present in MVs and promotes pro-inflammatory responses, we investigated whether MVs released by LPS-stimulated monocytes are enriched in mitochondrial content and whether this content contributes to their ability to activate endothelial cells. Methods: MVs were isolated from conditioned media of THP-1 monocytes by differential centrifugation, characterized by flow-cytometry and their ability to activate human umbilical vein endothelial cells (HUVECs) was tested. Results: MVs from LPS-stimulated monocytes that had been labelled with a mitochondrial and cytoplasmic dye were enriched in mitochondrial dye, mitochondrial RNA, and stained positively the mitochondrial outer membrane protein TOM22. These MVs induced IL-8 production and VCAM and ICAM mRNA level in HUVECs. Blocking of IL-1beta, which has been previously reported to be present in MVs, only had a moderate effect on MV-induced HUVEC activation. However, the pro-inflammatory potential of MVs was dramatically reduced when MVs were derived from cells, i) depleted for mitochondrial DNA, and ii) cultivated in the presence of pyruvate, which alters mitochondrial activity. Moreover, only mitochondria isolated from LPS-stimulated monocytic cells were able to activate ECs. Conclusions: Thus, MVs released by LPS-stimulated monocytes are enriched in mitochondrial content. Furthermore, mitochondrial stress and activity rather than simply mitochondrial content defines ability of MVs released by LPS-stimulated monocytes to induce an EC response. Advanced Clinical Seminar 4 Familial Hypercholesterolaemia - Practice Essentials ACS4:1. COST EFFECTIVENESS OF CASCADE TESTING FOR FAMILIAL HYPERCHOLESTEROLAEMIA, BASED ON DATA FROM FH SERVICES IN THE UK Pears2, Zofia Miedzybrodzka3, Kate Steve Humphries1, Robert Cather5, Melanie Watson6, Marion Haralambos4, Moyra Kerr7. 1 Institute of Cardiovascular Science, University College London, London, United Kingdom; 2 Hampshire County Council, Winchester, United Kingdom; 3 University of Aberdeen, Polwarth Building, Aberdeen, United Kingdom; 4 Wales Heart Research Institute, Heath Park, Cardiff University, Cardiff, United Kingdom; 5 Northern Ireland Regional Genetics Centre, Belfast, United Kingdom; 6 University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom; 7 Insight Health Economics Ltd, Southampton, United Kingdom Aim: Familial Hypercholesterolaemia (FH) is a vastly under-diagnosed genetic disorder associated with early development of coronary heart disease (CHD) and premature mortality, which can be substantially reduced by effective treatment. Patents have recently expired on highintensity statins used to treat FH, reducing treatment costs. Here we build a model using UK data to estimate the costs and benefits of DNA testing of relatives of those with monogenic FH. Methods: A decision tree and a Markov model were used to estimate lifetime costs and cost effectiveness of cascade testing, using UK data from audit and on-going cascade services. Results: The estimated Incremental Cost Effectiveness Ratio (ICER) was £5,981 and the overall net marginal lifetime cost per relative tested was
Conclusions: Polyunsaturated lipid species of HDL, primarily PA(36:4), PA(38:4), PA(38:5), PA(38:6), PG(36:2), LPC(18:2), PE(34:2) and PE(38:6), are most strongly affected by genetic apoA-I deficiency. WORKSHOP 1.4 Immunometabolism: the interface of immune and metabolic responses in disease W1.4:3. IMPAIRED FATTY ACID SYNTHESIS AFFECTS IMMUNE CELLS ACTIVATION: FOCUS ON STEROL REGULATORY ELEMENT BINDING FACTOR-1C ON T LYMPHOCYTES Fabrizia Bonacina1, Gaia Cermenati1, Donatella Caruso1, Alberico Luigi Catapano1, 2, Nico Mitro1, Giuseppe Danilo Norata1, 3, 4. 1 Department of Pharmacological and Biomolecular Sciences University of Milan, Milan, Italy; 2 IRCSS Multimedica, Milan, Italy; 3 Centro SISA per lo studio dell aterosclerosi, Ospedale Bassini, Milan, Italy; 4 William Harvey Research Institute Barts and The London School of Medicine & Dentistry Queen Mary University, London, United Kingdom Aim: Intracellular metabolism has recently recognized as a key determinant of immune cells differentiation and activation; whereas activated T cells relay on glycolysis, naïve, memory and regulatory Tcells use fatty acids oxidation(FAO) for their metabolic demand. We investigated how key proteins regulating intracellular fatty acid (FA) metabolism (SREBP1c) affected the polarization of CD4Tcells Methods: A detailed immunophenotyping through flow cytometry and metabolic profiling of isolated Tregulatory(CD4+CD25+) and Tconventional(CD4+CD25-) cells was performed in SREBP1cKO and WT littermates Results: SREBP1c deficiency resulted in a significant reduction of T cells fueled by FAO: CD4+CD44+ (18.48±1.03% vs 22.85±0.54%, p<0,01), CD8+CD44+ (11.63±0.82% vs 14.86±1.24%,p<0,05), and Tregulatory CD4+CD25hiFoxP3+ cells (2.61±0.25% vs 3.38±0.10%, p<0,01). To unrevail the role of FA in Tcells, metabolomic analysis was performed on isolated cells. SREBP1cKO Treg showed a reduction of FA synthesis with accumulation of acetilCoA(2.73±0.3vs4.52±0.59 ng/mgprotein,p<0,01) which led to an accumulation of medium-chain acetylcarnitines (C8: 3.8 ±0.6 vs 6.2±0.07; C10 :2.4±0.04 vs 4.6±0.05; C14: 1.02±0.1 vs 1.8±0.2,pg/mgprotein,p<0,01), suggesting an incomplete FAO; glycolisis was also affected with accumulation of lactate(13.47±2.53 vs 36.25±7.48,ng/mgprotein, p<0,01) in Treg of SREBP1cKO. This phenotype was peculiar of Treg as metabolites of Tconv were similar between SREBP1cKO and WT, thus addressing a key role of FA metabolism in Treg but not other CD4Tcells. Conclusions: Treg may relay on a “futile” cycle by producing and burning FA. SREBP1c represents a key player of FA metabolism and its deficiency affects Treg metabolism leading to reduced levels of these cells. Therefore, reprogramming Tcell FA metabolism may represent a therapeutic target for dysregulations of immune activation.
W1.4:2. CLEC4E SIGNALING PROMOTES PRO-ATHEROGENIC MACROPHAGE RESPONSES ment1, Gemma Basatemur1, Leanne Masters1, Lauren Marc Cle Baker1, Patrick Bruneval2, Taka Iwawaki3, Manfred Kneilling4, Sho Yamasaki3, Jane Goodall1, Ziad Mallat5. 1 University of Cambridge, e et de la Cambridge, United Kingdom; 2 Institut National de la Sant Recherche M edicale, Paris, France; 3 Kyushu University, Kyushu, Japan; 4 Eberhard Karls University, Tübingen, Germany; 5 Inserm U970Department of Cardiovascular research, Paris, France Aim: Tuberculosis granulomas share similar features with arterial atherosclerotic plaques. The presence of a necrotic core and the accumulation of lipid promote progression towards an unstable atherosclerotic lesion. Clec4e (Mincle) receptor mediates macrophage activation in response to mycobacterial glycolipid, but also senses damaged cells and drives inflammatory activation in response to necrotic cell death. Our aims were to examine the role of Clec4e in atherosclerosis development and identify the signaling pathways that mediate macrophage responses to Clec4e stimulation
e23
Methods: Male 6-8 week old Ldlr–/– mice were lethally irradiated then reconstituted with bone marrow cells from donor wildtype or Clec4e deficient mice. Mice were fed a high fat diet and atherosclerosis development examined at 20 weeks. In vitro experiments utilized bone marrow-derived macrophages and peritoneal macrophages derived from gene targeted mice deficient in Clec4e or defective in ER stress signaling pathways (CHOP, IRE-1 and ATF3). Results: Clec4e deletion in vivo substantially reduced macrophage inflammation, proliferation and foam cell formation in response to hypercholesterolemia, and significantly limited atherosclerosis. In vitro experiments revealed that Clec4e signaling induced a Syk-mediated ER stress response, leading to the induction of pro-inflammatory mediators (e.g., Tnf, Il6, Ccl2) and growth factors (e.g., Csf1), and inhibition of cholesterol efflux. Chop and Ire1 deficiencies significantly limited Clec4e-dependent effects, whereas Atf3 deficiency promoted both Clec4e expression and downstream inflammatory responses. Conclusions: Our results identify a non-redundant role for Clec4e in coordinating major pathways involved in advanced atherosclerosis and suggest that it may play similar roles in orchestrating granuloma formation
W1.4:3. INHIBITION OF GLYCOLYSIS REDUCES INTRAPLAQUE ANGIOGENESIS IN A MOUSE MODEL OF ADVANCED ATHEROSCLEROSIS Bieke Van Der Veken, Guido De Meyer, Wim Martinet. Laboratory of Physiopharmacology, University of Antwerp, Antwerp, Belgium Aim: Intraplaque (IP) neovascularization is a critical factor in atherosclerotic plaque rupture. Recent studies in cancer research have demonstrated that proliferating endothelial cells generate up to 85% of their ATP from glycolysis. Because 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) plays a critical role in glycolysis, we investigated whether PFKFB3 inhibition affects IP neovascularization and plaque stability in ApoE-/- mice containing a heterozygous mutation in the fibrillin-1 gene Fbn1C1039G, a model of advanced atherosclerosis with IP neovascularization. Methods: ApoE-/- Fbn1C1039G+/- mice were fed a western diet (WD). PFKFB3 inhibitor 3-(3-pyridinyl)-1-(4-pyridinyl)-2-propen-1-one (3PO, 50 mg/g, i.p.) or solvent was administered starting either after 4 weeks WD (2x/week, 10 weeks, preventive regimen) or after 16 weeks WD (4x/week, 4 weeks, curative regimen). Results: 3PO reduced IP neovascularization and haemorrhages by 50% (preventive regimen) and 38% (curative regimen). This compound had no effect on smooth muscle cell content in the plaques (preventive: 7±1% vs. 7±1% in control; curative: 9±1% vs. 8±1% in control). Similarly, the collagen deposition in the plaques was not affected (preventive: 16±4% vs. 16±1% in control; curative: 25±1% vs. 26±2% in control). However, 3PO tended to decrease the macrophage content (preventive: 8±2% vs. 14±4%; curative: 5±1% vs. 7±1%). Plasma VEGF-A levels decreased significantly (curative: 838±449 vs. 2871±653 pg/ml, p¼0.027) and cardiac function improved after 10 weeks of treatment (fractional shortening 31±4% vs. 23±3%, p¼0.013; LVIDd 4.6±0.2mm vs. 4.0±1mm, p¼0.032, LVIDs 3.7±0.1mm vs. 2.8±0.3mm, p¼0.009). Conclusions: Inhibition of PFKFB3 by 3PO significantly represses IP angiogenesis and haemorrhages in mice, demonstrating its potential in preventing plaque rupture. WORKSHOP 2.4 Regulators of metabolism and cardiometabolic disease W2.4:1. INSULIN SIGNALING DETERMINES ANABOLIC ENERGY UPTAKE PROCESSES INTO BROWN FAT DURING CATABOLIC CONDITIONS OF ADAPTIVE THERMOGENESIS Fischer1, Renate Schreiber2, Rudolf Markus Heine1, Alexander € rg Heeren1. 1 University Medical Center Zechner2, Ludger Scheja1, Jo Hamburg-Eppendorf, Hamburg, Germany; 2 University of Graz, Graz, Austria
e24
Abstracts / Atherosclerosis 263 (2017) e1ee28
Aim: Catabolic, cold activated brown adipose tissue burns triglycerides for heat production. Consequently, endogenous lipid stores need to be replenished by anabolic processes including fatty acid uptake by active adipocytes. The aim of this study was to investigate the catabolic and anabolic processes in lipid handling of activated BAT.
lower MTTP expression in cardiomyocytes. In mice, MTTP-A deficient mice displayed impaired heart function after an experimental myocardial infarction.
W2.4:3. MITOCHONDRIAL ACTIVITY IS A MAJOR CONTRIBUTOR TO THE PROINFLAMMATORY CAPACITY OF MICROVESICLES Florian Puhm1,2, Taras Afonyushkin2, Georg Obermayer2, Christoph Binder2. 1 Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria; 2 Research Center for Molecular Medicine (CeMM) of the Austrian Academy of Sciences, Vienna, Austria
ĂMethods: BAT activity was stimulated by cold exposure or CL316,243 (CL) treatment in wildtype and transgenic mice. The uptake processes were investigated by metabolic turnover studies intravital microscopy and magnetic resonance imaging after injection of nanoparticle labelled TRL. Results: Increased BAT activity is accompanied by enhanced insulin secretion. CL treatment stimulated anabolic processes in BAT via insulin dependent phosphorylation of Akt kinase. This process is dependent on CD36 and is associated with facilitated whole particle uptake. Inhibition of insulin secretion using the potassium channel agonist diazoxide or impairing insulin signalling with insulin receptor blocking during activation abolished TRL uptake into BAT. Conclusions: Our data show that cold promotes catabolic as well as anabolic processes in BAT whereas insulin orchestrates metabolic pathways that controls lipoprotein handling for the replenishment of endogenous energy stores. Impaired lipoprotein processing mediated by BAT in insulin resistant states could lead to dyslipidemia observed in patients suffering from type 2 diabetes mellitus.
W2.4:2. MICROSOMAL TRIGLYCERIDE TRANSFER PROTEIN IN THE ISCHEMIC HEART ang1, Marcus Ståhlman1, Ewa Martina Klevstig1, Margareta Scharin T€ n1. 1 The Wallenberg Laboratory, Ehrenborg2, Malin C. Levin1, Jan Bore Institute of Medicine, Department of Molecular and Clinical Medicine, University of Gothenburg, Gothenburg, Sweden; 2 Atherosclerosis Research Unit, Department of Medicine, Center for Molecular Medicine, Karolinska Institute, Stockholm, Sweden Aim: Myocardial ischemia is associated with cardiac dysfunction and lipid accumulation. However, the underlying molecular(s) are still poorly understood. The microsomal triglyceride transfer protein (MTTP), which is critical for hepatic lipoprotein assembly and secretion, is also expressed in cardiomyocytes. The aim of this study was to assess the relationship between the MTTP and cardiac function after a myocardial infarction. Methods: Patients with suspected coronary artery disease (n¼310) underwent echocardiography and myocardial perfusion scintigraphy examinations, and were genotyped for the MTTP polymorphism rs1800804. The cardiac MTTP expression was examined in 126 biopsies from the left ventricle of patients undergoing elective heart surgery. Heart function in MTTP-A heart-specific knockout mice were analyzed using echocardiography at baseline and after myocardial infarction. Results: Subjects with the minor rs1800804 C-allele had lower MTTP expression and significantly lower stress systolic tissue velocity as well as higher infarct and wall motion scores compared with non-carriers. The minor allele of the MTTP polymorphism rs3816873 (known as Ile128Thr), which is in complete allelic association with rs1800804, was significantly (P¼0.001) associated with lower expression of MTTP in cardiomyocytes. In mice, MTTP-A deficiency did not affect the baseline heart function but displayed significantly smaller ejection fraction and stroke volume 24h after myocardial infarction, compare to littermates controls. Conclusions: The MTTP rs1800804 polymorphism showed significant associations with structural and perfusion abnormalities reflecting myocardial infarction and stress-induced cardiac dysfunction along with
Aim: Microvesicles (MVs) are recognized as promoters of inflammation and increased numbers of MVs have been described in cardiovascular diseases. Because mitochondrial content has been shown to be present in MVs and promotes pro-inflammatory responses, we investigated whether MVs released by LPS-stimulated monocytes are enriched in mitochondrial content and whether this content contributes to their ability to activate endothelial cells. Methods: MVs were isolated from conditioned media of THP-1 monocytes by differential centrifugation, characterized by flow-cytometry and their ability to activate human umbilical vein endothelial cells (HUVECs) was tested. Results: MVs from LPS-stimulated monocytes that had been labelled with a mitochondrial and cytoplasmic dye were enriched in mitochondrial dye, mitochondrial RNA, and stained positively the mitochondrial outer membrane protein TOM22. These MVs induced IL-8 production and VCAM and ICAM mRNA level in HUVECs. Blocking of IL-1beta, which has been previously reported to be present in MVs, only had a moderate effect on MV-induced HUVEC activation. However, the pro-inflammatory potential of MVs was dramatically reduced when MVs were derived from cells, i) depleted for mitochondrial DNA, and ii) cultivated in the presence of pyruvate, which alters mitochondrial activity. Moreover, only mitochondria isolated from LPS-stimulated monocytic cells were able to activate ECs. Conclusions: Thus, MVs released by LPS-stimulated monocytes are enriched in mitochondrial content. Furthermore, mitochondrial stress and activity rather than simply mitochondrial content defines ability of MVs released by LPS-stimulated monocytes to induce an EC response. Advanced Clinical Seminar 4 Familial Hypercholesterolaemia - Practice Essentials ACS4:1. COST EFFECTIVENESS OF CASCADE TESTING FOR FAMILIAL HYPERCHOLESTEROLAEMIA, BASED ON DATA FROM FH SERVICES IN THE UK Pears2, Zofia Miedzybrodzka3, Kate Steve Humphries1, Robert Cather5, Melanie Watson6, Marion Haralambos4, Moyra Kerr7. 1 Institute of Cardiovascular Science, University College London, London, United Kingdom; 2 Hampshire County Council, Winchester, United Kingdom; 3 University of Aberdeen, Polwarth Building, Aberdeen, United Kingdom; 4 Wales Heart Research Institute, Heath Park, Cardiff University, Cardiff, United Kingdom; 5 Northern Ireland Regional Genetics Centre, Belfast, United Kingdom; 6 University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom; 7 Insight Health Economics Ltd, Southampton, United Kingdom Aim: Familial Hypercholesterolaemia (FH) is a vastly under-diagnosed genetic disorder associated with early development of coronary heart disease (CHD) and premature mortality, which can be substantially reduced by effective treatment. Patents have recently expired on highintensity statins used to treat FH, reducing treatment costs. Here we build a model using UK data to estimate the costs and benefits of DNA testing of relatives of those with monogenic FH. Methods: A decision tree and a Markov model were used to estimate lifetime costs and cost effectiveness of cascade testing, using UK data from audit and on-going cascade services. Results: The estimated Incremental Cost Effectiveness Ratio (ICER) was £5,981 and the overall net marginal lifetime cost per relative tested was