tbuckley/cabot-search huggingface dataset:
Abstract 5542: Annexin A5 Reduces Inflammation Mediated Vascular Remodelling and Post-interventional Atherosclerosis and Improves Vascular Function in Hypercholesterolemic Mice
Authors: Mark M Ewing, Margreet de Vries, Mariette Nordzell, J W Jukema, Johan Frostegard, Knut Pettersson, Paul Quax
Journal: Circulation (2009)

Annexin A5 is abundant in atherosclerotic plaques, has anti-thrombotic properties, and it may reduce ischaemia-reperfusion injury. We showed that annexin A5 could reduce neointima development in mouse models of vein graft restenosis and cuff induced neointima formation in hypercholesterolemic ApoE3*Leiden mice. These effects were associated to a reduction in vessel wall leucocytes, indicating an anti-inflammatory effect. Here we further investigated if annexin A5 possess anti-inflammatory properties, and can affect functional consequences of inflammation in the vessel wall. Methods. Plasma cytokines were measured by multiplex immunoassay in hypercholesterolemic ApoE3*Leiden mice 28 days after the placement of a vein graft in the carotid artery. Mice were treated with 1 mg/kg bw of annexin A5 or placebo once daily by intraperitoneal injection. In a second experiment, ApoE (−/−) mice were given a western diet for 16 weeks, after which they were treated with annexin A5 or placebo for 3 days, as above. They were then anaesthetised (isoflurane) and a Samba Preclin pressure transducer was introduced into the aortic arch through a carotid artery. Endothelium mediated dilatation was induced by intraperitoneal injection of 3 μ g metacholine. Results. Plasma levels of G-CSF, IFN γ and MIP-1 β /CCL4 were significantly reduced by annexin A5 28 days after surgery. Vein graft remodelling was reduced by 48±12% in the annexin A5 treated mice. In apoE (−/−) mice, diastolic and systolic blood pressure were not significantly different. Placebo treated mice responded to metacholine with a minor reduction in diastolic (−1 mmHg at 3 minutes after injection) and systolic blood pressure (−5 mmHg). In contrast, annexin A5 treated mice responded with a pronounced and more long-lasting reduction in diastolic (− 11 mmHg) and systolic (−22 mmHg) blood pressures, p &lt; 0.05 for both pressures. Conclusions. Annexin A5 has systemic anti-inflammatory properties, as shown by reduced plasma cytokine levels, as well as it (as previously shown) blocks vascular inflammation in disease models. It can also normalise disease related impairment of endothelium mediated dilatation. Annexin A5 may have therapeutic benefits in inflammation associated vascular disease.
Abstract 5550: C-reactive Protein (CRP) Causes Insulin Resistance in Mice Through Fc <i>γ</i> RIIB-mediated Inhibition of Insulin Signaling
Authors: Keiji Tanigaki, Chieko Mineo, Christopher Longoria, Wanpen Vongpatanasin, Philip W Shaul
Journal: Circulation (2009)

Insulin promotes the cardiovascular protective functions of the endothelium including NO production by activating endothelial NO synthase (eNOS). Insulin activation of eNOS increases skeletal muscle blood flow and thereby augments glucose uptake. C-reactive protein (CRP), which is modestly elevated in chronic inflammatory conditions including obesity, is positively correlated with type 2 diabetes. We recently showed in cultured endothelium that CRP antagonizes insulin signaling to eNOS by inhibiting the phosphorylation of Akt and eNOS, and that this occurs by CRP binding to the inhibitory IgG receptor Fc γ receptor IIB (Fc γ RIIB). In this study we determined if the antagonism of insulin signaling by CRP causes insulin resistance in mice. We found that CRP transgenic mice (TG-CRP) with CRP levels of 14±8 μ g/ml were hyperinsulinemic, hyperglycemic, and hyperleptinemic. In addition, TG-CRP displayed impaired glucose tolerance and impaired insulin tolerance, and skeletal muscle glucose uptake in vivo was attenuated by 57%. There was no difference in energy expenditure or food intake, but TG-CRP weighed 4% less and had 62% greater fat content than controls. The role of Fc γ RIIB was determined in littermates from matings of TG-CRP with Fc γ RIIB −/− mice. CRP was &lt;1 μ g/mL in mice lacking CRP transgene and 13±2 and 10±3 μ g/ml in Fc γ RIIB +/+ TG-CRP and Fc γ RIIB −/− ;TG-CRP, respectively. Compared to Fc γ RIIB +/+ , fasting insulin was markedly increased in Fc γ RIIB +/+ ;TG-CRP; in contrast, it was normal in Fc γ RIIB −/− ;TG-CRP. Whereas Fc γ RIIB +/+ ;TG-CRP were insulin resistant, Fc γ RIIB −/− ;TG-CRP were not. Immunohistochemistry with anti-mouse Fc γ RIIB/Fc γ RIII Ab in Fc γ RIII −/− mice detected Fc γ RIIB protein in skeletal muscle microvascular endothelium, whereas endothelium in Fc γ RIIB −/− was negative. Fc γ RIIB protein was not detected in skeletal muscle cells or adipose. These findings indicate that CRP causes insulin resistance in mice that is due to impaired skeletal muscle glucose uptake and is mediated by Fc γ RIIB that is most likely in endothelium. Future therapies targeting Fc γ RIIB may potentially normalize both the endothelial dysfunction and insulin resistance characteristic of obesity and other chronic inflammatory conditions.
Abstract 5588: Identification of Aria as a Novel Factor Regulating Endothelial Cell Apoptosis and Angiogenesis in vivo
Authors: Masahiro Koide, Koji Ikeda, Maki Uraoka, Yusuke Nakagawa, Yoshiki Akakabe, Hiroaki Matsubara
Journal: Circulation (2009)

Endothelial apoptosis is a pivotal process for angiogenesis during embryogenesis as well as postnatal life. Here, we identified a novel gene (ARIA) that regulates endothelial apoptosis and angiogenesis. ARIA was expressed in a variety of human cultured endothelial cells as well as in blood vessels of e9.5d mouse embryos. Knockdown of ARIA in HUVEC using siRNA significantly attenuated endothelial apoptosis, but not affected cell migration or proliferation. This anti-apoptotic effect by ARIA-knockdown was attributable to the enhanced expressions of inhibitor of apoptosis (cIAP)-1 and cIAP-2. cIAP-1 and cIAP-2 play as ‘guardians’ of the cell death machinery by directly binding to and neutralizing the caspases as well as by modulating the death signaling through TNF receptors. Simultaneous knockdown of cIAP-1 and cIAP-2 abolished the anti-apoptotic effect of ARIA-knockdown. On the other hand, yeast two-hybrid screening identified the 20S proteasome α subunit-7 as a binding partner of ARIA. We then found that cIAP-1 and cIAP-2 are targeted by the proteasome, and that ARIA regulates the proteasomal degradation of cIAP-1 and cIAP-2 in endothelial cells. In vivo angiogenesis was studied by Matrigel-plug assay and mouse ischemic retinopathy model, in which ARIA was knocked down by mixing siRNA in the plugs and intravitreal injection of siRNA respectively. In both the models, ARIA-knockdown significantly enhanced the in vivo angiogenesis through attenuating the endothelial apoptosis. To further study ARIA function in vivo, we have generated the ARIA knockout mice. Tumor xenograft growth was significantly enhanced in ARIA knockout mice than that in wildtype mice. The number of microvessels was significantly greater with appearance of less apoptotic endothelial cells in the tumor xenografts implanted into ARIA knockout mice than in wildtype mice. Taken together, ARIA is a novel factor regulating endothelial apoptosis as well as angiogenesis through modulating the proteasomal degradation of cIAP-1 and cIAP-2 in endothelial cells. Since ARIA is preferentially expressed in endothelial cells, ARIA is an attractive new target for pharmacotherapeutic agents to treat ischemic cardiovascular diseases.
Abstract 5484: Activation of Endothelial NF- <i>κ</i> B Signaling Promotes Coagulation by Inhibiting Protein C Anticoagulant Mechanism in Endotoxemic Mice
Authors: Dongmei Song, Xiaobing Ye, Gang Liu, Shu Fang Liu
Journal: Circulation (2009)

Although the role of systemic activation of NF- κ B pathway in septic coagulation has been well documented, little is known about the mechanistic contribution of endothelial intrinsic NF- κ B signaling in this pathological process. This study defined the causative role of endothelial NF- κ B signaling in septic coagulation. Wild type (WT) and transgenic mice (TG) that conditionally overexpress a mutant I- κ B β , an inhibitor of NF- κ B, selectively on endothelium, were injected with saline (1 ml/kg, i.p.) or E Coli LPS (5 mg/kg, i.p.). Tissue fibrin deposition, plasma markers of coagulation, plasma levels of protein C and plasminogen activator inhibitor-1 (PAI-1) were measured at 6 hours after LPS injection. Immunohistochemical staining of frozen tissue sections of heart, liver and kidney from WT-LPS mice showed a widespread tissue fibrin deposition. Fibrin deposition was not evident in tissue sections of the three organs from TG-LPS mice. Compared with WT-Con and TG-Con mice, WT-LPS mice showed a 79% reduction in plasma fibrinogen level, which was restored to control level in TG-LPS mice. WT-LPS displayed 13.7- and 3.2-fold increase in plasma levels of thrombin-antithrombin and D-dimer, which were reduced by approximately 69% and 37% in TG-LPS mice. Plasma levels of total and activated protein C (mO.D. units) for WT-Con, TG-Con, WT-LPS and TG-LPS groups were: 73.4±2.4, 72.0±3.2, 26.0±6.2 and 58.5±4.7 (p &lt; 0.01, WT-LPS vs other 3 groups), and 45.6±1.6, 43.0±1.2, 2.8±1.8 and 29.9±4.1 (p &lt; 0.01, WT-LPS vs other 3 groups). Plasma level of PAI-1 (ng/ml) for WT-Con, TG-Con, WT-LPS and TG-LPS groups was 0.06±0.05, 0.0±0.0, 31.3±4.8 and 18.1±3.3 (p &lt; 0.05, WT-LPS vs other 3 groups). These results indicate that endothelial intrinsic NF- κ B signaling plays a pivotal role in the activation of coagulation in endotoxemic mice, and suggest that activation of endothelial NF- κ B pathway promotes coagulation by impairing the protein C anticoagulant mechanism and by inhibiting the fibrinolytic system. (Supported by NIH R01GM063907).
Abstract 5558: Inflammasome Activation in Cardiac Fibroblasts is Essential for Myocardial Ischemia-reperfusion Injury
Authors: Masanori Kawaguchi, Masafumi Takahashi, Takeki Hata, Yuichiro Kashima, Yasuko Takahashi, Junji Sagara, Shun’ichiro Taniguchi, Uichi Ikeda
Journal: Circulation (2009)

Background: Inflammatory responses play a key role in the pathophysiology of myocardial ischemia-reperfusion (I/R) injury. We previously investigated the role of ASC (apoptosis-associated speck-like protein containing a caspase recruitment domain), an adaptor protein that forms inflammasome whose activation leads to caspase-1-dependent interleukin (IL)-1 β maturation, in myocardial I/R injury and found that ASC deficiency prevented IL-1 β secretion and inflammatory cell infiltration, resulting in improving myocardial injury and remodeling. In this study, we investigated the mechanisms by which I/R initiates activation of inflammasome in the heart. Methods and Results: To examine what kind of cells are responsible for inflammasome activation in the heart, primary cardiomyocytes (CM) and cardiac fibroblasts (CF) from the wild-type mice were prepared. Although ASC was clearly expressed in both CM and CF, IL-1 β secretion was detected in only CF after stimulation with relatively high dose of lypopolysaccharide (LPS: 100 ng/mL). The intracellular pro-IL-1 β accumulation in CF was similar between wild-type (WT) and ASC deficient (ASC −/− ) mice; however, IL-1 β processing and secretion were significantly inhibited in ASC −/− -CF, compared with that in WT-CF (p&lt;0.01). Hypoxia/reoxygenation (H/R: 6 h of H following 18 h R) dramatically induced IL-1 β secretion in CF after low dose (10 ng/mL) LPS priming. To determine the mechanisms by H/R might activate inflammasome, CF were treated with ATP (10 mM), HMGB1 (10 mg/mL), and K+ ionophore nigericin (1mM) after LPS priming. Marked IL-1 β secretion was detected only in nigericin-treated CF. Further, H/R-induced IL-1 β secretion was significantly inhibited by the treatment with antioxidant N-acetyl-L-cysteine (NAC: 10 mM), K + channel blockers (glimepiride 10 mM, glibenclamide 10 mM, TEA 10 mM) or high extracellular K + (130 mM), indicating that inflammasome activation in response to H/R might be mediated through K+ efflux and ROS production. Conclusion: These findings demonstrate that initial activation of inflammasome in response to I/R occurs in CF, but not in CM, in the heart, and suggest that inflammasome in the CF could be a potential target for the treatment of myocardial I/R injury.
Abstract 5495: More Rapid and Consistent Inhibition of Platelet Aggregation is Achieved by Loading With Ticagrelor Compared to Clopidogrel in Patients With Acute Coronary Syndromes: Results From the PLATO PLATELET Substudy
Authors: Robert F Storey, Shankar B Patil, Rosemary Ecob, Dominick J Angiolillo, Lars Wallentin
Journal: Circulation (2009)

Background: Ticagrelor (T) is an oral reversible P2Y 12 receptor antagonist that does not require conversion to an active metabolite for antiplatelet activity, unlike clopidogrel (C). The PLATO study compared the efficacy of T and C in patients with a broad range of acute coronary syndromes (ACS). In this substudy (PLATO PLATELET), we assessed the onset and extent of inhibition of platelet function in PLATO study patients. Methods and Results: 24 C-naive patients with NSTE ACS or STEMI undergoing primary PCI and sequentially randomised in a double blind, double dummy design to C (300mg [n=7] or 600 mg load [n=5]) or T (180mg load [n=12]) in the PLATO study in a single centre were entered into the first phase of PLATO PLATELET. Light transmittance aggregometry (LTA) with ADP (5 and 20 uM) and whole blood single platelet counting aggregometry (WBSPC) using ADP 1–100 uM was performed prior to study drug administration and 1, 2, 4, 8 and 12 hours after study drug. VerifyNow P2Y12 (VN) and VASP assays were also performed pre and 4h post study drug. Data obtained after abciximab administration was excluded except for VASP data. There was more rapid and greater inhibition of platelet aggregation with T vs C, with most T-treated patients showing a substantial effect at 1h post dose that was sustained until 12h post dose (Figure ). VN data at 4h were 273±124 and 68±97 PRU for C and T respectively (p&lt;0.01). VASP data showed a similar trend. C 300 vs 600mg doses showed the same patterns of LTA response. Conclusion: T 180mg loading dose has a faster onset of action with greater inhibition of platelet function compared to C in patients with ACS. WBSPC and VN can rapidly assess the early effects of P2Y 12 antagonists.
Abstract 5604: Refining Clinical Trial Composite Outcomes With Investigator-Assessed Weights: An Application to the ASSENT-3 Trial
Authors: Paul W Armstrong, Cynthia M Westerhout, Frans Van de Werf, Robert M Califf, Lars Wallentin, Robert C Welsh, Robert G Wilcox, Jeffrey A Bakal
Journal: Circulation (2009)

Background: Declining cardiac mortality and rising costs of clinical trials places a new priority on efficient use of all patient outcomes. Whereas traditional time-to-event analysis exclusively assigns equal weight to the first event in the composite end point, this is counterintuitive to stakeholders. Methods: We surveyed clinical investigators and asked them to assess the relative severity weights they would place on death, recurrent myocardial infarction (re-MI), cardiogenic shock and congestive heart failure (CHF) in ST-elevation myocardial infarction (STEMI) patients. Their assessment was then applied to a modified survival analysis of selected 30 day endpoints in the ASSENT-3 trial which randomized 6095 STEMI patients and compared three reperfusion strategies: tenecteplase (TNK) + unfractionated heparin (UH); TNK + enoxaparin (enox); TNK + abciximab (abx). Results: Respondents (n=23) allocated relative values from a standard point scale which was converted to a single denominator (2.0) resulting in the following weights: death 1.0, shock 0.5, CHF 0.3 &amp; re-MI 0.2. The Table provides the event rates calculated according to the first event as well as at any time during 30-day follow-up (Panel A). In Panel B traditional first event versus weighted composites using first event and all events in each patient are shown. Note that when the traditional time-to-event analysis is re-examined with a weighted composite there is an attenuation of the excess events initially observed with UH (p=0.05 vs p=0.18). By contrast, when all events from each patient are used in the weighted composite, a trend for benefit with enox was observed (p=0.15). Conclusions: This approach adds potential value to traditional analytical techniques by more efficiently incorporating the differential value of all events in each patient thereby providing new options for future trial design and analysis. Table 1.
Abstract 5572: RAGE Signaling in Macrophages Contributes to Atherosclerosis in ApoE Null Mice
Authors: Xiaoping Shen, Rosa Rosario, Yan Lu, Shi Fang Yan, Ann Marie Schmidt
Journal: Circulation (2009)

Macrophage-derived foam cell formation is an essential process in atherosclerosis. RAGE (Receptor for Advanced Glycation Endproducts) and its ligands play a role in atherosclerotic lesion formation, especially in diabetes. RAGE is expressed in monocytes/macrophages and previous studies revealed key roles for RAGE in macrophage migration and production of cytokines. To test the role of RAGE signaling in monocytes/macrophages, we developed transgenic mice expressing cytoplasmic domain-deleted RAGE (dominant-negative RAGE (DN-RAGE) in macrophages under control of the Macrophage Scavenger Receptor-type A promoter to study the role of RAGE in atherosclerosis (noted as MSR-DN-RAGE). Four groups of mice, all in apoE−/− background and fed with normal chow diet, were tested under diabetic (D) and non diabetic ND) conditions. At age 24 weeks, lesion areas by en face analysis of entire aorta and at the aortic sinus were significantly reduced in MSR-DN-RAGE+/apoE−/− vs. apoE−/− mice (in both ND and D) (Table ). Immunohistochemistry of lesions demonstrated significantly reduced % of macrophages/lesion area in both ND and D MSR-DN-RAGE+/apoE−/− vs. apoE−/− mice, and in D mice, significantly lower % smooth muscle cells/lesion area in MSR-DN-RAGE+/apoE−/− vs. apoE−/− mice (Table ). The % T cells/lesion area were not different among the ND and D groups (Table ). We conclude that macrophage RAGE signaling critically contributes to atherosclerosis in apoE−/− mice irrespective of the diabetic state.
Abstract 5505: The Impact of Selectively Performed Echocardiography in Patients With Acute Ischemic Stroke or Transient Ischemic Attack
Authors: Gui-Hua Yao, Darrel Grigerick, Gustavo Camarano, Carmel Armon, Leng Jiang
Journal: Circulation (2009)

Background: The updated ACC/AHA/ASE guideline in 2003 recommended that echocardiography be performed selectively in patients with acute ischemic stroke or TIA. We aimed to evaluate the diagnostic yield and therapeutic impact of transthoracic echocardiography (TTE) with such an approach. Methods: A total of 984 consecutive patients with acute ischemic stroke or TIA were included in the study. Clinical data were systemically reviewed, including the reports of ECG, brain MRI/CT and carotid duplex ultrasound (CDUS). TTE data were retrospectively analyzed. Results: TTE tests were performed in 624 (63.4%) patients (mean age 70.9±14.1 years, 47.4% of men). Atrial fibrillation (AF) was present in 116 (18.6%) patients. An overall potential cardiac source of embolism (PCSE) was found in 155 (24.8%). Atrial septal abnormality (PFO± septal aneurysm) and LV dysfunction (EF ≤ 30%± wall motion abnormality/LV aneurysm) were the most frequent PCSE in younger (&lt; 45 years) and older (≥ 45 years) patients, respectively. The overall diagnostic yield of TTE was comparable in both groups (35.5% vs 26.8%, P = 0.303). Significant carotid stenosis was found in 27 (7.5%) patients in the older group by CDUS, but none in the younger patients. After excluding patients with AF and significant carotid stenosis, who have independent indication for anticoagulation or intervention, the therapeutic impact of TTE was more significant in younger patients (27.6% vs 11.5%, P = 0.019). Numbers needed to test (NNT) for detection of a PCSE was 4 in younger patients and 9 in older patients, the latter being more than 2-fold of the former. Conclusion: Selectively performed TTE in patients with ischemic stroke or TIA can provide important information on PCSE. The diagnostic yield and therapeutic impact are much higher in younger patients. Table. Potential cardiac source of embolism
Abstract 5528: Novel Role of PKC <i>ζ</i> -ERK5 Complex in TNF <i>α</i> -mediated eNOS Protein De-stabilization
Authors: Patrizia Nigro, Jun-ichi Abe, Chang-Hoon Woo, Kimio Satoh, Carolyn McClain, Michael R O’Dell, Hakjoo Lee, Jae-Hyang Lim, Jian-Dong Li, Kyung-Sun Heo, Keigi Fujiwara, Bradford C Berk
Journal: Circulation (2009)

Background: Laminar steady (s−) flow-induced activation of ERK5 leads to KLF2 activation and subsequent eNOS expression, thus maintaining normal endothelial cell (EC) function. In contrast, PKC ζ has emerged as a pathological mediator of EC dysfunction based on a positive correlation between PKC ζ activity and disturbed (d−) flow; and the essential role of PKC ζ activation in TNF α stimulation of JNK, caspase-3 and EC apoptosis. Emerging evidence demonstrates the reduction of eNOS expression in d-flow area, but the molecular mechanisms remain unknown. Methods and Results: First, both TNF α and d-flow activated PKC ζ , and TNF α inhibited s-flow-induced eNOS protein expression in EC. Interestingly, the reduction of eNOS expression by TNF α was abolished by adenoviral infection of a dominant negative PKC ζ (Ad.DN-PKC ζ ). However, Ad.DN-PKC ζ could not reverse the TNF α -mediated reduction of KLF2/eNOS mRNA expression. These data portend a post-translational downregulation of eNOS expression via PKC ζ . Pretreatment with MG132 (proteosome inhibitor) inhibited TNF α -mediated reduction of eNOS protein, suggesting involvement of the ubiquitin-proteosome system. In vitro run-off assays showed that TNF α de-stabilized eNOS, and transduction of Ad.DN-PKC ζ stabilized eNOS, which suggested a key role of PKC ζ activation on eNOS stability. Using a mammalian two-hybrid assay we found a direct association between PKC ζ and ERK5. Further, we found that the catalytic domain of PKC ζ (aa 405–591) and the C-terminal region of ERK5 (aa 571– 806) appeared to be the domains required for this direct interaction. In vitro kinase assays revealed that Ser 486 of ERK5 is a novel phosphorylation site of PKC ζ . Then, we investigated the contribution of both PKC ζ -ERK5 binding and phosphorylation on eNOS stability. First, overexpression of the ERK5 fragment (aa 571– 806) inhibited PKC ζ -ERK5 binding and PKC ζ -mediated reduction of eNOS. Second, we found that an ERK5S486A mutant (Ad.ERK5 S486A) significantly inhibited eNOS de-stabilization compared with ERK5 wild type (Ad.ERK5-WT). Conclusion: These data suggest a key role of PKC ζ - ERK5 complex in TNF α -mediated eNOS protein de-stabilization and subsequent EC dysfunction.