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RED BLOOD CELL DERIVED MICROPARTICLES ARE THROMBOGENIC IN VITRO AND IN MOUSE MODELS OF ATHEROSCLEROSIS IN VIVO
Workshops WO3 Thrombogenic risk factors for atherothrombosis
WO3 THROMBOGENIC RISK FACTORS FOR ATHEROTHROMBOSIS WO3-OR3 RED BLOOD CELL DERIVED MICROPARTICLES ARE THROMBOGENIC IN VITRO AND IN MOUSE MODELS OF ATHEROSCLEROSIS IN VIVO H. Isobe 1 , T. Perkmann 2 , J.M. Breuss 1 , C.J. Binder 2 , C.M. Boulanger 3 , B.R. Binder 1 . 1 Department of Vascular Biology and Thrombosis Research, Center for Biomolecular Medicine and Pharmacology, Medical University of Vienna, Vienna, Austria; 2 Clinical Institute of Medical & Chemical Laboratory Diagnostics, Medical University Vienna, Vienna, Austria; 3 Institut National De La Santé Et De La Recherche Médicale (Inserm), Unit 689, Cardiovascular Research Center Lariboisière, and University Paris VII, Paris, France In normal individuals microparticles (MPs) that are thrombogenic in vitro but not in vivo (thrombin antithrombin complexes, TAT, upon injection in mice) are found in the circulation. MPs obtained during endotoxinaemia express tissue factor (TF) and are thrombogenic also in vivo. When not directly thrombogenic MPs were co-injected with TF bearing MPs, TAT formation was significantly enhanced, indicating that not-directly thrombogenic MPs need tissue factor “priming” to become thrombogenic in vivo. To prove this hypothesis, we injected red blood cell (RBC) derived MPs (106-108) that were found to exhibit the highest “enhancing” activity into wild type C57BL/6 mice and into ApoE-/- or LDLR-/- deficient mice, fed a high lipid diet. TAT complexes increased significantly only in ApoE-/or LDLR-/- mice (PBS 4.4±0.5 vs 108 RBCMPs 15.8±1.9µg/L). This indicates that tissue factor “priming” also occurs in atherosclerotic mice, likely by tissue factor expressed on the plaque or by plaque derived tissue factor bearing MPs. In fact, RBCMPs also increased the number of fibrin positive plaques in LDLR-/- mice as compared to PBS. This indicates that RBC derived MPs are thrombogenic in animal models of atherosclerosis. When MPs isolated form the arterial blood of atherosclerotic patients undergoing carotid endarterectomy were analyzed, it was found that MPs from symptomatic patients were more thrombogenic and that this increased thrombogenicity was due to increased number of red blood cell derived MPs. This indicates that red blood cell derived MPs might also cause thrombus formation in atherosclerotic patients. WO3-OR4 ASPIRIN RESISTANCE IS A RISK FACTOR FOR NON-FATAL CORONARY EVENTS AFTER PERCUTANEOUS CORONARY INTERVENTIONS A.B. Catakoglu 1 , S. Aytekin 2 , H. Celebi 1 , M. Sener 2 , H. Kurtoglu 2 , I.C.C. Demiroglu 1 , V. Aytekin 2 . 1 Florence Nightingale Hospital, Department of Cardiology, Istanbul, Turkey; 2 Istanbul Bilim University, Florence Nightingale Hospital, Department of Cardiology, Istanbul, Turkey Background: Aspirin resistance is associated with poor prognosis, like higher incidences of myocardial infarction (MI), stroke, and cardiovascular death among stable cardiovascular patients, a higher incidence of reocclusion after peripheral angioplasty, and more myonecrosis after elective percutaneous coronary interventions (PCI). The objective of our study is to evaluate the relationship between aspirin resistance (AR) and non-fatal clinical endpoints during the long term follow-up after successful PCI. Methods: One-hundred patients (49 patients with, 51 without clinical end points) were evaluated for aspirin resistance at the end of two years after the index PCI. Non-fatal coronary events were defined as the occurrence of non-fatal MI, coronary artery bypass graft surgery or repeat PCI. AR was tested by platelet function analyzer (PFA)-100. A normal closure time with the collagen/ADP and the collagen/epinephrine cartridge was defined as aspirin resistance in patients under regular aspirin treatment.
Results: The incidence of aspirin resistance was significantly higher (p=0.021) in patients with clinical endpoints (22.4%) compared to patients without any endpoints (5.9%). AR was found to be an independent risk factor for non-fatal coronary events after adjustment for other potential risk factors (p=0.021). Conclusions: Despite regular treatment with aspirin, the incidence of aspirin resistance determined by a point-of-care assay is significantly higher in patients who develop non-fatal coronary events on long term follow-up after elective PCI. These findings raise the possibility that aspirin resistance might be an important risk factor that could affect the outcome of PCI. WO3-OR5 PRESENCE OF TYPE 2 DIABETES SIGNIFICANTLY MODULATES THE CARDIOVASCULAR RISK CONFERRED BY THE PLASMINOGEN ACTIVATOR INHIBITOR-1 -675 5G/4G POLYMORPHISM C.H. Saely 1,2,3 , A. Muendlein 1,3 , A. Vonbank 1 , S. Aczel 1,2 , T. Marte 1,2 , P. Rein 1,2,3 , L. Risch 1 , H. Drexel 1,2,3,4 . 1 Vorarlberg Institute for Vascular Investigation and Treatment (VIVIT), Feldkirch, Austria; 2 Department of Medicine, Academic Teaching Hospital Feldkirch, Feldkirch, Austria; 3 University for Human Sciences, Triesen, Principality of Liechtenstein; 4 Drexel University College of Medicine, Philadelphia, PA, USA Background and aims: We aimed at studying the association of the -675 5G/4G polymorphism of the plasminogen activator inhibitor-1 (PAI-1) gene with angiographically determined coronary artery disease (CAD) and its impact on future vascular events in patients with type 2 diabetes (T2DM) and in non-diabetic subjects. Methods: Genotyping was performed in 672 consecutive Caucasian patients undergoing coronary angiography for the evaluation of stable CAD. Vascular events were recorded over 4 years. Results: The prevalence rates of the 5G/5G, the 5G/4G, and the 4G/4G genotypes were 17.6%, 52.7%, and 29.7% in patients with T2DM (n = 148) and 23.5%, 48.3%, and 28.2% in non-diabetic subjects (n = 524), respectively. In non-diabetic subjects, the homozygous PAI-1 4G4G genotype was significantly associated with significant coronary stenoses ≥50% (adjusted odds ratio (OR) 1.85 [95%CI 1.20-2.85]; p = 0.005); however, no such association was observed in T2DM patients (OR 0.81 [0.33-1.93]; p = 0.627). An interaction term T2DM x 4G4G genotype was significant (p = 0.014), indicating a significantly stronger association of the polymorphism with CAD in non-diabetic subjects than in patients with T2DM. Also prospectively, the 4G4G genotype conferred an increased risk of vascular events in non-diabetic subjects but not in T2DM patients, with adjusted hazard ratios of 1.74 [1.12-2.70]; p = 0.014 and 0.67 [0.30-1.44]; p = 0.297, respectively. Again, the interaction T2DM x 4G4G genotype was significant (p = 0.027). Conclusions: Presence of T2DM significantly modulates the vascular risk conferred by the PAI-1 -675 5G/4G polymorphism in angiographied coronary patients. WO3-OR6 THE PROTHROMBOTIC PHENOTYPE OBSERVED IN NIDDM IS INDEPENDENT OF BLOOD GLUCOSE LEVELS R. Hernandez-Vera, G. Vilahur, E. Pena, R. Ferrer, L. Badimon. Cardiovascular Research Center, CSIC-ICCC, Hospital De La Santa Creu I Sant Pau, Barcelona, Spain Objectives: Non-insulin dependent Diabetes mellitus (NIDDM) is associated with a high risk of thrombosis. However, the mechanisms leading to this increased risk remain unknown. Therefore, the aim of this study was to investigate the role of hyperglycaemia in arterial thrombosis in an in vivo experimental model. Methods: Zucker Diabetic Fatty (ZDF) and control lean rats (ZDFC) (13-week old) were anesthetized and an abdominal incision performed to expose a mesenteric loop that was placed on the intravital microscope plate. Rose Bengal solution (50mg/kg 1ml bolus) was injected and a mesenteric arteriole irradiated, within 30 minutes, to induce a vascular lesion. The full thrombotic occlusion (OT) was monitored by intravital microscopy. Additionally, OT was monitored in 13-week-old Zucker Fatty rats (ZF). Results: ZF and ZDFC rats showed similar blood glucose levels (86±7 and 92±4mg/dL) whereas ZDF rats reflected their diabetic condition with significantly higher glucose levels (458±18 mg/dL; p<0,0001). Interestingly, ZDF and ZF rats showed similar and significantly lower occlusion
77th Congress of the European Atherosclerosis Society, April 26–29, 2008, Istanbul, Turkey
WORKSHOPS
Results: Plasma PON1 activity toward HTL was by 43.5% lower in leptin-treated than in control animals. The amount of HTL linked to plasma proteins by peptide bond (the marker of protein homocysteinylation) was by 57.8% higher in leptin-treated than in control animals. Total homocysteine and lipid profile did not differ between groups. Conclusions: These data indicate that chronic hyperleptinemia impairs HTL catabolism in plasma by reducing PON1 activity. Increased level of protein homocysteinylation may contribute to proatherogenic effect of chronic hyperleptinemia.
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WO3 THROMBOGENIC RISK FACTORS FOR ATHEROTHROMBOSIS WO3-OR3 RED BLOOD CELL DERIVED MICROPARTICLES ARE THROMBOGENIC IN VITRO AND IN MOUSE MODELS OF ATHEROSCLEROSIS IN VIVO H. Isobe 1 , T. Perkmann 2 , J.M. Breuss 1 , C.J. Binder 2 , C.M. Boulanger 3 , B.R. Binder 1 . 1 Department of Vascular Biology and Thrombosis Research, Center for Biomolecular Medicine and Pharmacology, Medical University of Vienna, Vienna, Austria; 2 Clinical Institute of Medical & Chemical Laboratory Diagnostics, Medical University Vienna, Vienna, Austria; 3 Institut National De La Santé Et De La Recherche Médicale (Inserm), Unit 689, Cardiovascular Research Center Lariboisière, and University Paris VII, Paris, France In normal individuals microparticles (MPs) that are thrombogenic in vitro but not in vivo (thrombin antithrombin complexes, TAT, upon injection in mice) are found in the circulation. MPs obtained during endotoxinaemia express tissue factor (TF) and are thrombogenic also in vivo. When not directly thrombogenic MPs were co-injected with TF bearing MPs, TAT formation was significantly enhanced, indicating that not-directly thrombogenic MPs need tissue factor “priming” to become thrombogenic in vivo. To prove this hypothesis, we injected red blood cell (RBC) derived MPs (106-108) that were found to exhibit the highest “enhancing” activity into wild type C57BL/6 mice and into ApoE-/- or LDLR-/- deficient mice, fed a high lipid diet. TAT complexes increased significantly only in ApoE-/or LDLR-/- mice (PBS 4.4±0.5 vs 108 RBCMPs 15.8±1.9µg/L). This indicates that tissue factor “priming” also occurs in atherosclerotic mice, likely by tissue factor expressed on the plaque or by plaque derived tissue factor bearing MPs. In fact, RBCMPs also increased the number of fibrin positive plaques in LDLR-/- mice as compared to PBS. This indicates that RBC derived MPs are thrombogenic in animal models of atherosclerosis. When MPs isolated form the arterial blood of atherosclerotic patients undergoing carotid endarterectomy were analyzed, it was found that MPs from symptomatic patients were more thrombogenic and that this increased thrombogenicity was due to increased number of red blood cell derived MPs. This indicates that red blood cell derived MPs might also cause thrombus formation in atherosclerotic patients. WO3-OR4 ASPIRIN RESISTANCE IS A RISK FACTOR FOR NON-FATAL CORONARY EVENTS AFTER PERCUTANEOUS CORONARY INTERVENTIONS A.B. Catakoglu 1 , S. Aytekin 2 , H. Celebi 1 , M. Sener 2 , H. Kurtoglu 2 , I.C.C. Demiroglu 1 , V. Aytekin 2 . 1 Florence Nightingale Hospital, Department of Cardiology, Istanbul, Turkey; 2 Istanbul Bilim University, Florence Nightingale Hospital, Department of Cardiology, Istanbul, Turkey Background: Aspirin resistance is associated with poor prognosis, like higher incidences of myocardial infarction (MI), stroke, and cardiovascular death among stable cardiovascular patients, a higher incidence of reocclusion after peripheral angioplasty, and more myonecrosis after elective percutaneous coronary interventions (PCI). The objective of our study is to evaluate the relationship between aspirin resistance (AR) and non-fatal clinical endpoints during the long term follow-up after successful PCI. Methods: One-hundred patients (49 patients with, 51 without clinical end points) were evaluated for aspirin resistance at the end of two years after the index PCI. Non-fatal coronary events were defined as the occurrence of non-fatal MI, coronary artery bypass graft surgery or repeat PCI. AR was tested by platelet function analyzer (PFA)-100. A normal closure time with the collagen/ADP and the collagen/epinephrine cartridge was defined as aspirin resistance in patients under regular aspirin treatment.
Results: The incidence of aspirin resistance was significantly higher (p=0.021) in patients with clinical endpoints (22.4%) compared to patients without any endpoints (5.9%). AR was found to be an independent risk factor for non-fatal coronary events after adjustment for other potential risk factors (p=0.021). Conclusions: Despite regular treatment with aspirin, the incidence of aspirin resistance determined by a point-of-care assay is significantly higher in patients who develop non-fatal coronary events on long term follow-up after elective PCI. These findings raise the possibility that aspirin resistance might be an important risk factor that could affect the outcome of PCI. WO3-OR5 PRESENCE OF TYPE 2 DIABETES SIGNIFICANTLY MODULATES THE CARDIOVASCULAR RISK CONFERRED BY THE PLASMINOGEN ACTIVATOR INHIBITOR-1 -675 5G/4G POLYMORPHISM C.H. Saely 1,2,3 , A. Muendlein 1,3 , A. Vonbank 1 , S. Aczel 1,2 , T. Marte 1,2 , P. Rein 1,2,3 , L. Risch 1 , H. Drexel 1,2,3,4 . 1 Vorarlberg Institute for Vascular Investigation and Treatment (VIVIT), Feldkirch, Austria; 2 Department of Medicine, Academic Teaching Hospital Feldkirch, Feldkirch, Austria; 3 University for Human Sciences, Triesen, Principality of Liechtenstein; 4 Drexel University College of Medicine, Philadelphia, PA, USA Background and aims: We aimed at studying the association of the -675 5G/4G polymorphism of the plasminogen activator inhibitor-1 (PAI-1) gene with angiographically determined coronary artery disease (CAD) and its impact on future vascular events in patients with type 2 diabetes (T2DM) and in non-diabetic subjects. Methods: Genotyping was performed in 672 consecutive Caucasian patients undergoing coronary angiography for the evaluation of stable CAD. Vascular events were recorded over 4 years. Results: The prevalence rates of the 5G/5G, the 5G/4G, and the 4G/4G genotypes were 17.6%, 52.7%, and 29.7% in patients with T2DM (n = 148) and 23.5%, 48.3%, and 28.2% in non-diabetic subjects (n = 524), respectively. In non-diabetic subjects, the homozygous PAI-1 4G4G genotype was significantly associated with significant coronary stenoses ≥50% (adjusted odds ratio (OR) 1.85 [95%CI 1.20-2.85]; p = 0.005); however, no such association was observed in T2DM patients (OR 0.81 [0.33-1.93]; p = 0.627). An interaction term T2DM x 4G4G genotype was significant (p = 0.014), indicating a significantly stronger association of the polymorphism with CAD in non-diabetic subjects than in patients with T2DM. Also prospectively, the 4G4G genotype conferred an increased risk of vascular events in non-diabetic subjects but not in T2DM patients, with adjusted hazard ratios of 1.74 [1.12-2.70]; p = 0.014 and 0.67 [0.30-1.44]; p = 0.297, respectively. Again, the interaction T2DM x 4G4G genotype was significant (p = 0.027). Conclusions: Presence of T2DM significantly modulates the vascular risk conferred by the PAI-1 -675 5G/4G polymorphism in angiographied coronary patients. WO3-OR6 THE PROTHROMBOTIC PHENOTYPE OBSERVED IN NIDDM IS INDEPENDENT OF BLOOD GLUCOSE LEVELS R. Hernandez-Vera, G. Vilahur, E. Pena, R. Ferrer, L. Badimon. Cardiovascular Research Center, CSIC-ICCC, Hospital De La Santa Creu I Sant Pau, Barcelona, Spain Objectives: Non-insulin dependent Diabetes mellitus (NIDDM) is associated with a high risk of thrombosis. However, the mechanisms leading to this increased risk remain unknown. Therefore, the aim of this study was to investigate the role of hyperglycaemia in arterial thrombosis in an in vivo experimental model. Methods: Zucker Diabetic Fatty (ZDF) and control lean rats (ZDFC) (13-week old) were anesthetized and an abdominal incision performed to expose a mesenteric loop that was placed on the intravital microscope plate. Rose Bengal solution (50mg/kg 1ml bolus) was injected and a mesenteric arteriole irradiated, within 30 minutes, to induce a vascular lesion. The full thrombotic occlusion (OT) was monitored by intravital microscopy. Additionally, OT was monitored in 13-week-old Zucker Fatty rats (ZF). Results: ZF and ZDFC rats showed similar blood glucose levels (86±7 and 92±4mg/dL) whereas ZDF rats reflected their diabetic condition with significantly higher glucose levels (458±18 mg/dL; p<0,0001). Interestingly, ZDF and ZF rats showed similar and significantly lower occlusion
77th Congress of the European Atherosclerosis Society, April 26–29, 2008, Istanbul, Turkey
WORKSHOPS
Results: Plasma PON1 activity toward HTL was by 43.5% lower in leptin-treated than in control animals. The amount of HTL linked to plasma proteins by peptide bond (the marker of protein homocysteinylation) was by 57.8% higher in leptin-treated than in control animals. Total homocysteine and lipid profile did not differ between groups. Conclusions: These data indicate that chronic hyperleptinemia impairs HTL catabolism in plasma by reducing PON1 activity. Increased level of protein homocysteinylation may contribute to proatherogenic effect of chronic hyperleptinemia.
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