tbuckley/cabot-search huggingface dataset:
Abstract 5815: Therapeutic Targeting of the Calmodulin-Cyclin E Interaction in Vascular Smooth Muscle Cells
Authors: Sonya Hui, Jaehyun Choi, Syed Zaidi, Abdul Momen, Kiwon Ban, Mansoor Husain
Journal: Circulation (2009)

Background: Cell cycle regulation in vascular smooth muscle cells (VSMC) is a putative target in proliferative vascular diseases. Having shown that increases in intracellular [Ca 2+ ] are tightly coordinated and critical for VSMC proliferation, we also discovered that binding of Ca 2+ /calmodulin (CaM) to cyclin E/cdk2 is necessary for Ca 2+ -sensitive G 1 -to-S phase progression in VSMC. To test the importance of this, we developed a synthetic C aM- b inding sequence (CBS) that blocked CaM-cyclin E interactions, prevented activation of cdk2, and abrogated Ca 2+ -sensitive G1-to-S transitions in VSMC. Of note, binding of CaM to another target protein, calcineurin, was not altered by CBS. Objective: To evaluate the physiological relevance of targeting CaM-cyclin E interactions in human VSMC in vitro and in a mouse model of neointima formation in vivo. Methods &amp; Results: Human aortic SMC (HA-SMC) were treated with the CBS peptide conjugated to the viral TAT transduction domain to increase bioavailability. Peptide delivery of TAT-CBS was confirmed by immunochemistry. TAT-CBS caused a dose-dependent anti-proliferative effect in HA-SMC, as well as in human aortic endothelial cells and mouse embryonic fibroblasts (MEF) as measured by 3 H-thymidine incorporation. Importantly, these effects were lost in MEF from cyclin E1/E2 double knockout mice, further supporting target specificity for CaM/cyclin E. Moreover, TAT-CBS treatment was not cytotoxic, as it did not increase either LDH or caspase-3 release compared to controls. In vivo application of TAT-CBS in pluronic gel to the outside of injured mouse carotid arteries significantly decreased neointima formation and medial thickening without affecting re-endothelialization as compared to animals treated with vehicle-only or negative-control peptide. Summary: Inhibition of CaM binding to cyclin E/cdk2 with the TAT-CBS peptide significantly decreases HA-SMC proliferation in a dose-dependent manner in vitro. Moreover, application of TAT-CBS-containing gel to injured carotid arteries inhibits VSMC proliferation without affecting re-endothelialization. These data support TAT-CBS as a novel therapy for restenosis, and the general approach of targeting Ca 2+ -sensitive cell cycle control in VSMC.
Abstract 5787: Discovery and Characterisation of Linear and Cyclic Peptide Agonists of Apelins
Authors: Anthony P Davenport, Sarah L Pitkin, Janet J Maguire, Maximilian Macaluso, Robert C Glen
Journal: Circulation (2009)

The recently discovered apelin family of peptides mediate their actions by a single G-protein coupled receptor, APJ. We have previously shown apelins have three major actions in the human cardiovascular system: endothelium-dependent vasodilatation; direct vasoconstriction by interacting with smooth muscle APJ receptor and increased cardiac contractility by action on cardiac myocytes. [Pyr 1 ]apelin-13 was identified as the predominant isoform in human heart. Our aim was to discover shorter sequences of [Pyr 1 ]apelin-13 retaining agonist activity and use a computational ligand based strategy to design cyclic peptides. Over 30 compounds were synthesised and tested in a competition binding assay against [Glp65,Nle75,Tyr77] [ 125 I]Apelin-13. Functional assays measured the vaso-constrictor action in endothelium denuded human saphenous veins in oxygenated Krebs’ solution (37°C) in organ baths for isometric tension recordings. Cumulative concentration response curves were constructed to the endogenous and synthetic analogues. Responses were expressed as percentage of the terminal KCl (0.1M) constriction. Data are expressed as mean ± S.E. Mean and n-values are the number of patients from whom tissues were obtained. One micromolar concentrations of the predicted cleavage product of the angiotensin converting enzyme 2 (ACE-2), apelin-13(1–12), inhibiting radiolabelled apelin binding by 60.0±7.0% (n=3). The most potent cyclic analogue identified, MM07 inhibited binding by 42.2±4.8% (n=3) compared with 76.0±4.5% inhibition by (Pyr 1 )apelin-13. Both compounds potently constricted endothelium denuded saphenous vein (Apelin-13(1–12): pD 2 9.07±0.40, E max 29.30±9.43% KCl, n=5; MM07: pD 2 10.53±0.24, E max 21.80±5.72% KCl, n=3) with a comparable potency and efficacy to (Pyr 1 )apelin-13 (pD2 (pD 2 = 8.8±0.3, E MAX = 26±4%, n=15). These results show unexpectedly that the cleavage product of ACE-2 retains full agonist activity. The novel cyclic peptide retains potency and can be used as a pharmacological tool to characterise the apelin system and in the design of selective antagonists.
The Impact of Attained Educational Level on Incident Cardiovascular Events Differs Between High-Income Countries and Low-and-Middle-Income Countries
Authors: Abhinav Goyal
Journal: Circulation (2009)

Abstract #899 Abhinav Goyal, Emory Rollins Sch of Public Health and Emory Sch of Med, Atlanta, GA; Deepak L Bhatt, VA Boston Healthcare System and Brigham and Women’s Hosp, Boston, MA; Ph. Gabriel Steg, INSERM U-698, Univ Paris 7, AP-HP, Paris, France; Bernard J Gersh, Mayo Clinic, Rochester, MN; Mark J Alberts, Northwestern Univ Feinberg Sch of Med, Chicago, IL; E Magnus Ohman, Duke Clinical Res Inst, Durham, NC; Ramón Corbalán, Pontificia Univ Católica, Santiago, Chile; Kim A Eagle, Univ of Michigan Medical Ctr, Ann Arbor, MI; Efrain Gaxiola, Ctr Especializado en Terapia Endovascular, Jardínes Hosp de Especialidades, Guadalajara, Mexico; Runlin Gao, Fuwai Hosp, Beijing, China; Shinya Goto, Tokai Univ Sch of Med, Kanagawa, Japan; Ralph B D’Agostino, Boston Univ, Boston, MA; Robert M Califf, Duke Clinical Res Inst, Durham, NC; Sidney C Smith Jr, UNC Ctr for Cardiovascular Science and Med, Univ of North Carolina–Chapel Hill, Chapel Hill, NC; Peter W Wilson, Emory Sch of Med, Atlanta, GA Abhinav Goyal, 2009 Finalist and Presenting Author
Abstract 5807: Psychological Stress Impairs Ischemia-induced Neovascularization
Authors: Fritz Maingrette, Julie Turgeon, Paola Haddad, Jessika Groleau, Gemma Perez, Sylvie Dussault, Alain Rivard
Journal: Circulation (2009)

Background: Psychological stress (PS) is a major risk factor for cardiovascular diseases but the underlying mechanisms are still largely unknown. Here we tested the hypothesis that PS might decrease neovascularization in response to ischemia. Methods and results: Balb/c mice were subjected to restraint stress by placing them in a well ventilated 50 mL conical centrifuge tube for 20 min each day for 14 days. Control mice were left unperturbed in their home cage with free access to food and water. After two weeks of this stress protocol, hindlimb ischemia was surgically provoked by femoral artery removal and hindlimb perfusion was then evaluated by Laser Doppler. Mice exposed to PS showed a significantly lower rate of blood flow recovery compared to control mice at day 14 (0.60±0.04 vs 0.78±0.05, p&lt;0.05) and day 21 (0.61±0.07 vs 0.80±0.07, p&lt;0.05) and had a significantly lower capillary density in ischemic muscles (38±1 vs 74±3 capillaries/mm 2 , p&lt;0.001), as assessed by CD31 immunostaining. Endothelial progenitor cells (EPCs) have been shown to have an important role for postnatal neovascularization. We found that the number of peripheral EPCs was significantly decreased in PS mice compared to control mice and that EPCs from PS mice showed a significant impairment of their angiogenic activities (adhesion, migration, integration into tubules). Moreover, oxidative stress levels in EPCs isolated from mice exposed to PS were significantly increased as determined by DCF-DA and DHE immunostainings. Conclusions: PS is associated with a reduced neovascularization following ischemia. The potential mechanisms involved include increased oxidative stress, decreased EPCs number and impairment of their functional activities.
Abstract 5764: Discharge Without Antiplatelet Therapy After Inhospital Bleeding is an Independent Predictor of 6-Month Mortality Among Patients With Acute Coronary Syndrome: A Pooled Analysis From PURSUIT, PARAGON-A, PARAGON-B and SYNERGY
Authors: Mark Chan, Jie L Sun, Tracy Y Wang, Renato D Lopes, Marc E Jolicoeur, Karen S Pieper, Sunil V Rao, L. K Newby, Kenneth W Mahaffey, Robert A Harrington, Eric D Peterson
Journal: Circulation (2009)

Bleeding is an important complication of the management of acute coronary syndrome (ACS). Patients (pts) with bleeding are more likely to be discharged without antiplatelet therapy (AT); however, there are limited data on the impact of discharge without AT on longitudinal outcomes in this population. Methods: We examined discharge AT (aspirin and/or thienopyridine) use among 8582 pts who experienced inhospital bleeding in 4 large trials of antithrombotic therapy in ACS. After adjusting for the propensity to receive AT, we compared 6-month outcomes among pts discharged with at least one antiplatelet drug vs. those discharged without AT. Results: Almost 1 in 10 pts with bleeding were discharged without AT (n=826). These pts had more baseline comorbidities and were more likely to experience other inhospital non-fatal adverse events compared to patients discharged with AT. Adjusted outcomes associated with no AT vs. AT are shown in the Table . In an interaction analysis, the effect of discharge without AT was worst among pts with more severe bleeding and those treated with PCI. In a treatment effect by treatment intensity analysis, the adjusted hazard ratio for death or myocardial infarction was 1.45 (95% Confidence interval(CI) 1.08–1.94) for pts receiving monotherapy and 1.90 (95% CI 1.27–2.84) for patients receiving no AT, compared to patients receiving dual AT. Conclusions: Among patients with bleeding during ACS, discharge without antiplatelet therapy was associated with worse 6-month adverse outcomes. This effect was more pronounced among patients with more severe bleeding and among patients undergoing PCI. A gradient of better outcomes with greater AT intensity was observed. Thus, more research is required to determine the optimal approach to reinitiating AT among patients who bleed yet remain at high risk of recurrent ischemic events after discharge. Table. Six-month Outcomes Among Patients Discharged Without Vs. With Antiplatelet Therapy
Abstract 5808: Endothelial Cell Polyploidization Induces an Atherogenic Phenotype and is Prevented by Activating the Nampt-SIRT1 Axis
Authors: Nica M Borradaile, J. Geoffrey Pickering
Journal: Circulation (2009)

Polyploid endothelial cells (ECs) are found in aged and atherosclerotic arteries. However, whether increased chromosome content has an impact on EC function is unknown. To interrogate the process by which ECs become polyploid we tracked cellular DNA content by flow cytometry in human aortic ECs as they replicated over 130 days. Strikingly, we observed that almost all ECs (99%) became tetraploid as they approached replicative senescence. Furthermore, the accumulation of tetraploid ECs was accelerated when cells were concurrently subjected to the oxidative stress of high glucose. To determine the impact of tetraploidy on EC function, independent of replicative senescence, we induced tetraploidy using the spindle poison, nocodazole. After a 24 h recovery, 70% of the EC population was tetraploid with no change in senescence-associated β -galactosidase activity. High density microarray expression analyses of tetraploid ECs revealed an atherogenic phenotype characterized by a cell cycle arrest profile (decreased CCNE2/A2 , RBL1 , BUB1B , increased CDKN1A ) and increased expression of genes involved in inflammation ( IL32 , TNFRSF21/10C , PTGS1 ) and extracellular matrix remodeling ( COL5A1 , FN1 , MMP10/14 ). Interestingly, aging-induced polyploidization was prevented by modest (1.6-fold) overexpression of the NAD + -regenerating enzyme, nicotinamide phosphoribosyltransferase (Nampt). The protection from polyploidization conferred by Nampt was not associated with enhanced PARP-1 or SIRT2 activity but with increased SIRT1 activity, which reduced cellular ROS and the associated oxidative stress stimulus for polyploidization. We conclude that human aortic ECs are prone to chromosome duplication that, in and of itself, can induce an atherogenic EC phenotype. Moreover, the emergence of tetraploid ECs can be prevented by optimizing the Nampt-SIRT1 axis. Strategies to maintain EC NAD + levels may represent a novel approach to mitigate the potentially deleterious accumulation of polyploid ECs associated with vascular disease.
Abstract 5783: <i>β</i> -Arrestin-Dependent Activation of Ca <sup>2+</sup> /Calmodulin-Dependent Kinase II Following <i>β</i> <sub>1</sub> -Adrenergic Receptor Activation
Authors: Supachoke Mangmool, Weili Zou, Lan Mao, Howard A Rockman
Journal: Circulation (2009)

Ca 2+ /calmodulin-dependent kinase II (CaMKII) is a serine/threonine kinase that phosphorylates a wide range of proteins involved in Ca 2+ homeostasis and appears to play a central role in the development of heart failure. The mechanism by which β -adrenergic receptor ( β AR) stimulation increases the activity of CaMKII remains unclear. In this study, we demonstrate that after isoproterenol (ISO) stimulation, CaMKII activity is significantly increased in hearts of wild-type and β 2 AR knockout mice, whereas ISO had no effect on CaMKII activity in hearts from β 1 AR knockout or β 1 β 2 AR double knockout mice. Since, recent studies have reported that β -arrestins can bind to calmodulin, we tested whether activation of the CaMKII signaling pathway is regulated by β -arrestin. ISO-mediated CaMKII activation, as well as downstream phospholamban phosphorylation at Threonine-17, was markedly inhibited in β -arrestin knockout mice. Similarly, the depletion of β -arrestin by small interference RNA in HEK-293 cells stably expressing β 1 ARs strongly inhibited ISO-mediated CaMKII activation indicating the necessity for β -arrestin in CaMKII activation. Using immunoprecipitation and confocal microscopy assays, we show that β 1 AR stimulation induces the formation of a β -arrestin-CaMKII complex at the plasma membrane. Moreover, after β 1 AR stimulation, the exchange factor directly activated by cAMP (Epac), which is known to mediate the activation of CaMKII, is also recruited to the membrane in a β -arrestin-dependent manner. Consistent with previous reports, treatment with PKI, an inhibitor of PKA, did not block the ISO-induced activation of CaMKII. In conclusion, we show that β 1 AR mediated activation of CaMKII requires the scaffolding of CaMKII and Epac by β -arrestin, allowing translocation of this multimeric complex to agonist-occupied β 1 ARs on the plasma membrane, which brings Epac and CaMKII in close proximity to where activator cAMP is being generated.
Abstract 5806: SRF Protects Brain Endothelial Cells Against Hypoxic Damage
Authors: Jianyuan Chai
Journal: Circulation (2009)

Ischemia resulting from brain vascular disorders is the major cause of stroke. Hypoxia triggers both angiogenesis and apoptosis through the induction of HIF1 α -activated VEGF and the alteration of mitochondrial permeability, respectively. The balance between these two events is crucial to both the progression of vascular disorders and the outcome of injury healing. Our previous study showed that SRF (Serum response factor) is essential to VEGF-induced angiogenesis. This study aimed to determine the roles of SRF in hypoxia-induced brain endothelial cell angiogenesis and apoptosis. Methods : Mouse brain endothelial cells (bEND3) were transfected with either an SRF expressing plasmid, SRF shRNA, or the vehicle (control), and cultured under hypoxic condition (5% CO 2 : 94% N 2 : 1% O 2 ) for 0, 0.5, 2, 6 and 24 hours. Angiogenesis and apoptosis were assessed by 3-D in vitro angiogenesis assay and Annexin V binding assay, respectively. Results : After 30-min hypoxic treatment, SRF mRNA expression was dramatically increased by 54 fold and then gradually declined and returned to normal at 24 hours. SRF protein expression and phosphorylation were also increased by 111±24 % and 74±7 % (both P &lt; 0.01), respectively, after 6-hour hypoxia. Hypoxia also enhanced SRF binding activity to DNA. Forced overexpression of SRF increased hypoxia-induced angiogenesis by 232±15 % (P &lt; 0.01); and knockdown of SRF completely abolished it. After 24-hour hypoxia, 29±4 % of the cells underwent apoptosis; while overexpression of SRF reduced this percentage to 5.7±1 %; and knockdown of SRF increased it to 85±4 % (all P &lt; 0.001). Overexpression of SRF increased Bcl-2/Bax ratio by 23±4 % at baseline and by 167±20 % after 24-hour hypoxia; knockdown of SRF decreased these ratios by 69±3 % and 75±8 %, respectively (all P &lt; 0.01). Knockdown of SRF also increased Bax translocation to mitochondria and Cytochrome C release. Conclusions : Hypoxia triggers SRF activation. Up-regulation of SRF promotes angiogenesis. Down-regulation of SRF sensitizes cells to hypoxia-induced apoptosis. SRF protects against hypoxia-induced apoptosis likely through both direct up-regulation of Bcl-2 and indirect down-regulation of Bax. This research has received full or partial funding support from the American Heart Association, Western States Affiliate (California, Nevada &amp; Utah).
Abstract 5573: Critical Role of Notch1 in Bone Marrow-derived Macrophages in Mediating Atherosclerosis
Authors: Qian Zhou, Hong-Wei Wang, William A Boisvert, James K Liao
Journal: Circulation (2009)

Background: Notch receptors regulate binary cell fate determination and are critical for embryonic development. However, the role of Notch signaling in the postnatal period remains to be determined. Although Notch receptors and ligands are expressed in atherosclerotic lesions, its functional role in macrophages in mediating atherosclerosis is unknown. Methods: To determine the role of macrophage Notch receptors in atherosclerosis, we transplanted bone marrow (BM) from wild-type (WT), Notch1 +/− and Notch3 −/− mice into irradiated recipient LDLr −/− mice. Atherosclerosis was induced with a 16-week diet containing 15.8% wt/wt fat and 1.25% cholesterol. The degree of atherosclerosis in the en face aorta and subaortic sinus was evaluated using Oil Red O staining. Macrophage recruitment and chemotaxis were evaluated by thioglycollate-induced peritonitis and in a modified Boyden chamber, respectively. Statistical analysis was performed using Mann-Whitney U -test. A p value &lt;0.05 was considered significant. Results: Physiological parameters after BM transplantation (BMT) and following atherogenic diet were not different between the 3 groups. Compared to WT BMT mice, Notch1 +/− BMT mice showed substantially less atherosclerotic lesions in the aorta (9.7% vs. 13.6%, p &lt;0.05) and subaortic sinus (515 ×10 3 μ m 2 vs. 696 ×10 3 μ m 2 , p &lt;0.05). In contrast, Notch3 −/− BMT mice developed similar degree of atherosclerosis compared to WT BMT mice (aortic lesion: 14.7%; subaortic sinus lesion: 670 ×10 3 μ m 2 ; p &lt;0.05 for both compared to WT BMT mice). This correlated with decreased recruitment of macrophages in response to thioglycollate-induced peritonitis in Notch1 +/− BMT mice, but not in Notch3 −/− or WT BMT mice. Indeed, Notch1 +/− macrophage exhibited decreased chemotaxis to monocyte chemotactic protein (MCP)-1. The decreased chemotaxis in Notch1 +/− macrophages was associated with decreased extracellular regulated kinase (ERK) phosphorylation. Conclusions: Our findings indicate that Notch1 in BM-derived macrophages contributes to atherosclerosis by mediating macrophage chemotaxis, in part, through the ERK signaling pathway and suggest that inhibition of Notch1 signaling in macrophages may have therapeutic benefits in preventing atherosclerosis.
Abstract 5769: Cardiovascular Outcomes for Patients Treated With Ezetimibe/Simvastatin Combination Compared With Simvastatin or Atorvastatin Alone
Authors: Karen M Stockl, Lisa Le, Shaoang Zhang, Ann S Harada, Brian K Solow, Scott D Ramsey
Journal: Circulation (2009)

Purpose: The efficacy of the combination of ezetimibe and simvastatin has been questioned following the results from the ENHANCE study, which found no difference in change in carotid intima-media thickness with ezetimibe/simvastatin combination compared with simvastatin alone. Because of the limited patient population (heterozygous familial hypercholesterolemia) and failure to examine cardiovascular events, additional research is necessary to evaluate clinical outcomes for patients using ezetimibe/simvastatin. Although a controlled clinical outcomes study is currently being conducted, results are not expected until 2012. Methods: Using administrative claims from a health insurance plan that included commercial and Medicare clients, we conducted a retrospective cohort analysis to compare the relative rates of clinical events (hospitalization for myocardial infarction (MI) or stroke) among patients age 18 to 84 with history of MI, stroke, or diabetes treated with ezetimibe/simvastatin combination versus simvastatin alone or atorvastatin alone. Simvastatin and atorvastatin-treated patients were each matched 1:1 with ezetimibe/simvastatin patients based on simvastatin daily dose equivalent and propensity score (derived using demographic and cardiovascular risk variables). Proportional hazards regression was performed with adjustment for demographics, medical history, and coronary heart disease medication use. Results: There were 9,983 patients in each cohort. The number of events per 100 person-years was 0.89 for ezetimibe/simvasatin, 0.93 for atorvastatin, and 1.05 for simvastatin. The risk of events was not significantly different for ezetimibe/simvastatin vs. atorvastatin alone (adjusted HR 0.89; 95% CI, 0.67–1.17), for ezetimibe/simvastatin vs. simvastatin alone (adjusted HR 0.80; 95% CI, 0.61 – 1.04), or simvastatin alone vs. atorvastatin alone (adjusted HR 1.11; 95% CI, 0.86 –1.44). Conclusions: Although the ENHANCE study raised questions on the efficacy of the ezetimibe/simvastatin combination, findings from this large population of high risk patients suggest that cardiovascular outcomes for patients treated with ezetimibe/simvastatin are similar to those treated with simvastatin or atorvastatin alone.