bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 948: An Allosteric Mechanism for Drug Block of a Cardiac Potassium Channel
Authors: Yang Tao , Smith Jarrod A , Meiler Jens , Wingo Tammy L , Kanki Hideaki , Leake Brenda , Sanders Charles R , Balser Jeffrey R , Roden Dan M 
Published: July 2021

Background: A common mechanism for block of ion channels is current inhibition by drug binding to residues - notably in S6 - within the permeating pore. Open state block is commonly observed.
Methods and Results: In this study, we used a combination of alanine/cysteine mutagenesis, patch clamp, and homology modeling to identify a novel allosteric mechanism for drug block of the human cardiac potassium channel KCNQ1 (the α-subunit encoding IKs). The initial mutagenesis experiments studied a total of 45 amino acid residues in the S6 segment (30 residues), and the proximal C-terminus (15 residues) of KCNQ1. Residues required for drug block were identified as alanine/cysteine mutants displaying <50% block of expressed current (n=4 – 6 each) upon exposure to drug concentrations inhibiting wild-type current by ≥90% (quinidine 100 μm, clofilium 30 μm and L-7 10 μm). Among the 30 residues in S6, there were five (F332, F335, S338, A341 and G348) displaying such reduced block and in the proximal C-terminus, 5/15 were less sensitive, including F351 which was near-totally resistant (current decrease = 4±3%). Homology modeling of KCNQ1 based on the Kv1.2 structure unexpectedly suggested that F351 faces away from the permeating pore, arguing against pore block as the mechanism for drug inhibition of KCNQ1 current. In the open channel model, F351 lines a pocket that also includes L251 and V254 in S4–S5. The model allows drug access to this pocket, and alanine substitutions at both sites yielded potassium currents that were resistant to drug block (↓34±4% for L251A and ↓40±5% for V254A).
Conclusion: These data strongly support a model in which open state block of this channel occurs not via binding to a site in the pore but rather by a novel allosteric mechanism, drug access to a side pocket generated in the open channel configuration and lined by S6 and S4/S5 residues.
Abstract 200: Beta-Myosin Heavy Chain Induction after Pressure Overload Is in a Minor Sub-population of Myocytes and Requires the Alpha-1A-Adrenergic Receptor
Authors: Lopez Javier E , Myagmar Bat-Erdene , Swigart Philip , Bigos Marty , Rodrigo Manoj , Simpson Paul 
Published: July 2021

Background: Induction of the fetal hypertrophic gene beta-myosin heavy chain (MHC) is a signature feature of pressure overload, and is thought to occur in most hypertrophied myocytes. Beta-MHC mRNA is not induced after transverse aortic constriction (TAC) in a double knockout (KO) model of the alpha-1A and alpha-1B-adrenergic receptor (AR) subtypes, but it is unknown whether the A or B or both are required.
Hypothesis: We tested the hypothesis that native beta-MHC protein induction is in a sub-population of myocytes and requires only a single alpha-1 subtype.
Methods: TAC was done in wild type (WT) and alpha-1 KO male mice ages 12–14 weeks. Beta-MHC protein was measured in isolated adult myocytes by a novel flow cytometry approach, with antibodies validated for beta-MHC and total sarcomeric MHC.

Results: In WT mice, the fraction of myocytes expressing beta-MHC was 3% in shams (SE =1, n =4 hearts), and increased to 26% of myocytes at 1–3 weeks after TAC (SE =4, n =8, p< 0.01 vs. sham). Myocytes expressing beta-MHC were predominantly large cells (see Figure

). In alpha-1A KO mice (AKO), beta-MHC was induced in only 6% of myocytes (SE =2, n =3, p<0.05 vs. WT TAC, p =NS vs. sham), or in only 15% as many myocytes as in WT hearts. Western blotting and quantitative RT-PCR confirmed reduced beta-MHC induction in alpha-1A KO myocytes.

Conclusion: Beta-MHC induction after pressure overload is in only a minor sub-population of cardiac myocytes, contrary to common models of fetal hypertrophic gene induction. Furthermore, beta-MHC induction requires a single alpha-1-AR subtype, the alpha-1A, which cannot be compensated by other hypertrophic receptors.
Abstract 1033: Simultaneous Clot-targeted Factor Xa Inhibition And Selective Blockade Of Activated GPIIb/IIIa On Platelets Results In Delayed But Potent Antithrombotic Effects Without Bleeding Time Prolongation.
Authors: Hagemeyer Christoph E , Eisenhardt Steffen U , Bassler Nicole , Stoll Patrick , Schwarz Meike , Chen Yung C , Ahrens Ingo , Bode Christoph , Peter Karlheinz 
Published: July 2021

Background: We generated phage-display-derived anti-GPIIb/IIIa single-chain antibodies (e.g. scFv SCE5) that specifically bind to the activated GPIIb/IIIa only and thus specifically block activated platelets only. ScFv SCE5 demonstrates strong antithrombotic potency, comparable to the conformation-unspecific blockers tirofiban and eptifibatide. In contrast bleeding times were not prolonged with scFv SCE5. Here we now use the possibility to add effector molecules using molecular biology methods. The highly potent anticoagulant TAP (tick anticoagulant peptide), which is a direct factor Xa (fXa) inhibitor, was used as an effector molecule.
Methods and Results: We genetically fused the activation-specific scFv with TAP, expressed the constructs in E.coli and purified the 39 kDa protein via its Histag binding to Nickel beads. Specific binding of the fusion molecules MA2/SCE5-TAP and strong inhibition of fibrinogen binding was proven in flow cytometry; anti-fXa activity was demonstrated in chromogenic assays. In vivo anticoagulative efficiency was determined by Doppler-flow in a ferric chloride-induced carotid artery thrombosis model in mice. Prolongation in occlusion time with SCE5-TAP was significantly stronger compared to SCE5 alone, recombinant TAP, non-binding mut-scFv-TAP as well as the clinical used drugs enoxaparine and eptifibatide. In contrast to the other anticoagulants tested, bleeding time was not prolonged by SCE5-TAP. Flow experiments studying platelet adhesion on collagen revealed a possible mechanism for the unique finding of a fully normal bleeding time: LIBS exposure on adhering platelets and as such the anticoagulative targeting potency of SCE5-TAP was delayed until considerable layers of platelets were deposited.
Conclusions: The combination of activation-specific GPIIb/IIIa blockade and fXa inhibition in one clot-targeted molecule further improves in-vivo antithrombotic efficiency without causing any bleeding time prolongation. The delay of the observed targeting effect may allow a sealing of injuries with platelet layers but may be in time for the prevention of occlusive platelet aggregates. The described blockers represent a new type of highly selective drugs that warrant further clinical development.
Abstract 1045: E-ntpdase-1/Cd39 Confers Anti-inflammatory And Immunomodulatory Properties To Circulating Membrane-derived Microparticles
Authors: Banz Yara , Beldi Guido , Wu Yan , Usheva Anny , Robson Simon C 
Published: July 2021

Background: Microparticles (MPs, <1.5ÂμM) are circulating, membrane-derived micro-vesicles shed from cells and platelets under physiological conditions as well as following stress, such as post-myocardial infarction. MPs have been implicated in inflammation, coagulation and vascular function. CD39, the prototype nucleoside triphosphate diphosphohydrolase (NTP-Dase1) within the vasculature modulates extracellular purinergic signalling through ATP and ADP hydrolysis, conferring anti-inflammatory, anti-thrombotic properties to the intravascular space. The aim of this study was to determine if CD39 is present on MPs and whether this impacts MP phenotype and function.
Methods: The proteome, absolute numbers as well as cellular origin of circulating MPs from wild type (wt) and cd39-null C57Bl6 mice were compared by 2D-gel electrophoresis, western blot and flow cytometry. Isolated MPs were incubated with endothelial cells (EC) to analyze their intrinsic pro-inflammatory potential.
Results: CD39 can be demonstrated and has ecto-enzymatic activity on circulating MPs from wt mice. 2D-gel analysis revealed that cd39-null MPs express lower levels of talin (component of focal adhesion) and ATP synthase, when compared to wild type MPs. Mutant mice have increased numbers of circulating MPs, with significantly higher fractions derived from platelets and endothelium as compared to wt mice (p<0.05). The presence of CD39 on wt MPs significantly attenuates inflammatory responses following incubation with EC as compared to cd39-null MPs (reduced IL-6 and TNF-alpha secretion, ICAM-1 and VCAM-1 expression, vWF release and NF-kappa B activation, p<0.05).
Conclusions: CD39 confers anti-inflammatory and immunomodulatory properties upon circulating MPs. These results highlight the protective potential of CD39; a finding that may be exploited therapeutically, with the prospective of administering soluble CD39 (apyrase) to the site of intravascular injury to ameliorate inflammation, as occurs for instance in acute coronary syndromes.
Abstract 1128: The Leukocyte Integrin Mac-1 Promotes Acute Cardiac Allograft Rejection
Authors: Shimizu Koichi , Libby Peter , Sakuma Masashi , Wang Yunmei , Mitchell Richard N , Simon Daniel I 
Published: July 2021

Background: In allograft rejection, donor endothelial cells (EC) are the principal early targets of host leukocytes and alloantibodies. Although the leukocyte integrin Mac-1(αmβ2, CD11b/ CD18) facilitates leukocyte-leukocyte as well as leukocyte-EC interactions, its roles in allograft survival and vasculopathy remains unclear. This study used murine cardiac transplantation to test the hypothesis that Mac-1 deficiency in the recipient reduces accumulation of graft infiltrating cells and attenuates cardiac allograft rejection.
Results: In total-allomismatched murine cardiac allografts (BALB/c donor hearts and C57BL/6 recipients), survival averaged 13.8 ± 2.3 days (n=6) for allografts in Mac-1-deficient (Mac-1−/−) recipients compared to 8.3 ± 1.3 days (n = 18, p<0.0001) in wild-type (WT) recipients. At 7 d post-transplantation, allografts in Mac-1−/− recipients had significantly lower parenchymal rejection (PR) scores (2.3 ± 0.4) than WT recipients (3.0 ± 0.4, p<0.01). Allograft accumulation of neutrophils, T cells, and macrophages (Mϕ) significantly diminished in Mac-1−/− compared to WT recipients. To determine the cell type involved in acute graft dysfunction, we performed adoptive transfer experiments. Adoptive transfer of WT, but not Mac-1−/−, Mϕ exacerbated parenchymal rejection of 7-day allografts placed into Mac-1−/− recipients (PR score: 2.3 ± 0.4 for WT vs. 1.5 ± 0.5 for Mac1−/− Mϕ; p < 0.05), and significantly reduced graft survival (8.0 ± 1.4 vs. 13.5 ± 2.6 days, p<0.01). Neither WT nor Mac-1−/− neutrophil adoptive transfer affected graft survival in Mac-1−/− recipients. Mac-1−/− Mϕ co-cultured with allo-EC (BALB/c) expressed significantly lower levels of the co-stimulatory molecules CD40 and CD80, and mixed leukocyte reaction using allo-EC-primed Mac-1−/− Mϕ showed significantly lower antigen-presenting function than WT Mϕ. Despite attenuating acute rejection, recipient Mac-1-deficiency did not prevent graft arterial disease.
Conclusion: These studies demonstrate that Mac-1 contributes to acute allograft rejection by modulating macrophage recruitment, antigen presentation, and T cell priming. These observations establish a molecular target for modulating recipient responses to prolong graft survival.
Abstract 1162: Proteomic Characterization of the Secretome of Peripheral Blood-derived Smooth Muscle Progenitors
Authors: Simper David , Mayr Ursula , Benbow Ulrike , Newby Andrew , Xu Qingbo , Mayr Manuel 
Published: July 2021

Background. Recent studies on circulating progenitor cells of the myeloid lineage have led to a new appreciation of their secretome, as paracrine factors may support tissue regeneration.
Methods and Results. Using a mass-spectrometry-based proteomic approach complemented by protein separation using two-dimensional gel electrophoresis, we compared the conditioned medium of plasma-derived smooth muscle progenitors (SPCs) and human aortic smooth muscle cells (SMCs). In total, over 150 individual protein features were identified. The majority of proteins were common to both cell lines, but higher amounts of the interstitial collagenase MMP-1, and of inflammatory cytokines, i.e. IL-8 and MCP-1, were found in the conditioned medium of SMCs compared to SPCs, which was subsequently verified by multiplex cytokine assays. ELISA measurements also confirmed that the concentrations of MMP-1 in the conditioned medium of SMCs exceeded the levels in the supernatant of SPCs. Although MMP-1 activity was partially antagonized in SMCs by a coordinated increase in TIMP-1, MMP-1 activity remained lower in SPCs. As a functional consequence, SMCs shedded more N-cadherin, an established MMP target, from their cell surface and showed a stronger invasive capacity. In contrast, SPCs produced more collagen, fibronectin and biglycan, but less perlecan than SMCs. A proteomic comparison between SPCs and endothelial progenitor cells (EPCs) revealed that the production of extracellular matrix proteins and the attenuated secretion of inflammatory cytokines was a specific characteristic of SPCs. EPCs secreted high levels of cathepsins, predominantly cathepsin D, B, Z and L, which were not detected in the conditioned medium of SPCs.
Conclusion. The present study constitutes the first comprehensive assessment of different circulating progenitors of the myeloid lineage demonstrating that apart from their potential physical contribution to lesion formation, SPCs might contribute to plaque stability by limiting inflammatory reactions and contributing to extracellular matrix deposition.
Abstract 241: Direct Injection of Bone Marrow Mononuclear Cells Reversed Experimental Diabetic Neuropathy by Augmenting Neovascularization and Providing Angio-neurotrophic Cytokines
Authors: Kim Hyongbum , Choi Yong Jin , Park Jong-seon , Ii Masaaki , Silver Marcy , Pfannl Rolf , Ropper Allan , Yoon Young-sup 
Published: July 2021

Background: Bone marrow (BM)-derived mononuclear cells (MNCs) have been shown to effectively treat ischemic cardiovascular diseases. Recent evidence suggested that diabetic neuropathy (DN) is causally related to impaired angio-vasculogenesis in vasa nervorum and deficiency of angiogenic and neurotrophic factors. Accordingly, we sought to investigate whether DN can be ameliorated by local injection of BM-derived MNCs.
Methods and Results: A severe peripheral neuropathy, characterized by significant slowing of motor nerve conduction velocities (MCV) developed 12 wks after the induction of diabetes with streptozotocin in Fisher rats (vs normal rats; 46.6±2.6 vs 32.0±2.5 m/s, P < 0.05). These rats were randomly assigned to MNC or saline injection groups (n = 9, each group) and received either 5x106 MNCs or saline intramuscularly around the sciatic nerves. In the MNC group, MCV were significantly improved within 4 wks after treatment (MNC vs Saline, 41.9±3.2 vs 32.7±2.8 m/s, P < 0.01). Microvascular circulation of sciatic nerve, measured by laser Doppler perfusion imaging was markedly increased only in the MNC group. Capillary density at 4 wks was significantly higher in the MNC group than in the saline group (68±5.9 vs 37±4.4 /cross section, P < 0.01). Robust engraftment of MNCs were observed in sciatic nerves, which sustained over 4 wks. A fraction of engrafted MNCs expressed endothelial markers suggestive of transdifferentiation into endothelial cells in the vasa nervorum. Intriguingly, a large number of the engrafted MNCs are following the course of vasa nervorum in close proximity. Real-time RT-PCR on sciatic nerves revealed that the expression of angio-neurotrophic factors were significantly increased in the MNC group compared to the saline group: VEGF (2.1 fold), FGF-2 (2.4), eNOS (18.1), Brain-derived neurotrophic factor (35.1), IGF-1 (25.5) (all P < 0.05). The protein levels were well correlated with mRNA expression levels.
Conclusion: Local transplantation of BM-derived MNCs could improve experimental DN by augmenting neovascularization and increasing angiogenic and neurotrophic factors in peripheral nerves. These findings suggest that BM-MNC transplantation may represent a novel therapeutic option for treating DN.
Abstract 1540: Weather/Temperature Change and Heart Disease
Authors: Chase-Ziolek Andrew , Carlsen Jeremy , LeRoy Dawn , Holm Karyn 
Published: July 2021

STUDY OBJECTIVE: Although recent studies have examined the effect of weather on acute coronary syndrome and heart failure, few have examined the influence of extreme weather and rapid temperature change on emergency department admissions for acute coronary syndrome and heart failure,
METHODS: We reviewed presentations of acute coronary syndrome (n = 2381) and heart failure (n = 1802) for the years 2003 to 2006 at an urban Level I Trauma Center and Accredited Chest Pain Center, examining presentation frequency on the warmest and coldest days of their respective years. In addition, we examined the frequency of presentation on days where the absolute difference between the mean temperature of one day and the next differed by 5, 10, and 15 degrees Fahrenheit. For each of these sample sets, we analyzed the data by gender and age.
RESULTS: Frequency of presentation did not significantly change on the hottest and coldest days of the year for acute coronary syndrome (p = 0.89 hot, p = 0.63 cold) or heart failure (p = 0.51 cold, p = 0.66 hot). No significant correlation was noted between gender and temperature extremes for acute coronary syndrome (p = 0.71 cold, p = 0.62 hot) or for heart failure (p = 0.83 cold, p = 0.59 hot). Age was not significantly correlated with temperature extremes for presentations of acute coronary syndrome (p = 0.72 cold, p = 0.63 hot) or heart failure (p = 0.95 cold, p = 0.99 hot). Changes in presentation frequency for either acute coronary syndrome (ACS) or heart failure (HF) at ΔT = 5°F were not significant (p = 0.70 ACS, p = 0.67 HF), nor were they significant at ΔT = 10°F (p = 0.97 ACS, p = 0.26 HF) or ΔT = 15°F (p = 0.17 ACS, p = 0.57 HF).
CONCLUSIONS: In theses patients, no significant correlations were noted between extreme weather events, temperature change and the presentation of acute coronary syndrome. In addition, no significant correlations were found between temperature differentials of 5, 10, or 15 °F and a diagnosis of acute coronary syndrome or heart failure.
Abstract 1590: Association Between Arterial Stiffness, Coronary Microcirculation And Left Ventricular Function In Patients With Newly Diagnosed Arterial Hypertension.
Authors: Ikonomidis Ignatios , Lekakis John , Paraskevaidis Ioannis , Triantafyllidi Helen , Papadopoulos Costas , Georgoula Georgia , Kremastinos Dimitrios T 
Published: July 2021

Arterial stiffness is an independent marker of cardiovascular morbidity and mortality. Coronary microcirculation is impaired in patients with arterial hypertension. We investigated the relationship between arterial stiffness, coronary microcirculation and left ventricular (LV) systolic and diastolic function.
METHODS: 80 untreated consecutive patients (mean age: 55±11 years 38 males), with newly diagnosed arterial hypertension and 20 healthy controls matched for sex, age and atherosclerotic factors, were studied. We measured a) Carotid to femoral artery pulse wave velocity (PWV) using the Complior apparatus b) Peak Systolic (Vs) and diastolic (Vd) coronary blood flow velocity, Vd/Vs ratio, Deceleration Time (DT-Vd) and time integral (VTI-Vd) of Vd using a 7MHZ transducer by means of colour-guided Doppler echocardiography at the distal tract of the LAD c) Ratio of VTI-Vd after adenosine infusion (140 μ g/kg/min) to VTI-Vd at baseline to assess coronary flow reserve (CFR) d) E and A doppler, Em, Am mitral annulus velocities TDI and E/Em ratio to assess LV diastolic function d) Mean Longitudinal, Transverse, Circumferential and Radial Strain and Strain Rate by 2-D Strain to assess LV systolic function.
RESULTS: Patients and controls had normal ejection fraction. Compared to controls, patients with hypertension had higher PWV (10.4±1.7 vs. 8.2±1.4 m/s, p<0.001), E/Em (8.3±2.8 vs. 5.7±1.4, p=0.001) and lower CFR (2.6±0.6 vs. 3.4±0.7, p<0.001), Vd/Vs (1.78±0.31 vs. 1.97±0.38, p=0.04), DT-Vd (973±226 vs 1113±332 ms, p<0.001), Em/Am (0.93±0.42 vs. 1.6±0.51, p<0.001), mean longitudinal strain (−17.8±3 vs. −19.8±3.1%, p=0.031) and mean circumferential strain ( −19.6±4.5 vs. −22±3.4 %, p=0.04). Increasing PWV was related to increasing E/Em (r=0.26, p=0.045) and decreasing CFR (r=−0.68, p<0.001). Increasing E/Em was related to decreasing Vd/Vs (r=−0.3, p<0.005) and CFR (r=−0.32, p=0.002).
CONCLUSIONS: Patients with arterial hypertension present subclinical systolic LV dysfunction and significant LV diastolic dysfunction compared to healthy controls. Increased LV diastolic filling pressures caused by arterial stiffness may increase the resistance of myocardial microcirculation leading to impaired coronary flow
Abstract 1690: Prevention of Contrast-Induced Nephropathy by Carperitide
Authors: Morikawa Shuji , Sone Takahito , Tsuboi Hideyuki , Mukawa Hiroaki , Morishima Itsuro , Uesugi Michitaka , Takagi Kensuke , Niwa Toru , Izumi Yusuke 
Published: July 2021

Introduction: Contrast-induced nephropathy (CIN) remains as a common complication of angiographic procedure. Carperitide, an antagonist of secretion of rennin, aldosterone and vasopressin with natriuretic effects, has renal protective effects.
Hypothesis: Carperitide may be effective in preventing CIN.
Methods: We prospectively studied 170 consecutive patients with chronic renal failure (serum creatinine(SCr) concentration >1.3mg/dl)who underwent coronary angiography. The patients were randomly assigned to either 1.3ml/kg/hr of lactated Ringer’s infusion plus carperitide 0.042μg/kg/min (Carperitide group N=86) or lactated Ringer’s infusion alone (Control group N=84). The administration was initiated 6 hours prior to the procedure and continued for 48 hours after angiography. The concentration of SCr and cystatin C were measured at baseline, 24 hours, 48 hours, 1 week, and 1 month following the angiography.

Results: The SCr concentration increased gradually up to one month in the Control group, whereas remained almost unchanged in the Carperitide group (p=0.001 for the trend, Figure

). The cystatin C concentration also showed the same trend (p=0.013 for the trend, Figure

). When CIN was defined as an increase of ≥0.5 mg/dl or ≥25% in the SCr at 48 hours after angiography, CIN developed in 7 of 84 patients (8%) in the Control group and 1 of 86 patients (1%) in the Carperitide group (P=0.047). Multivariate analysis disclosed that carperitide infusion (OR 0.097, P=0.041) and quantity of contrast media (OR 14.06, P=0.004) were significantly related to the development of CIN.

Conclusions: Carperitide is effective in preventing CIN in patients with chronic renal failure.