bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 5579: Possible Role of Platelet Reactivity in No-reflow Phenomenon in Patients With Acute Myocardial Infarction
Authors: Aurigemma Cristina , Scalone Giancarla , Barone Lucy , Di Monaco Antonio , Lamendola Priscilla , Sestito Alfonso , Lanza Gaetano A , Crea Filippo
Published: April 2024

Background
The no-reflow phenomenon has been documented in about 30% of patients with acute myocardial infarction (AMI) undergoing successful recanalization of the infarct-related coronary artery. Several mechanisms have been suggested for no-reflow, including leukocyte and platelet plugging. In this study we investigated whether platelet reactivity and platelet-leukocyte interaction are increased in AMI patients with evidence of no-reflow phenomenon.

Methods
We studied 14 patients 1 month after AMI (M/F 9/5; age 55±12), and 18 patients with stable coronary artery disease (CAD) (M/F 11/7; age 55±7). AMI patients were divided into two groups: 9 patients with normal coronary flow (group REFLOW) and 5 patients with no-reflow (TIMI flow ≤2 and myocardial blush grade ≤2: group NO-REFLOW). Flow cytometry was used to measure platelet expression of CD41 and glycoprotein IIb/IIIa epitope PAC-1, and monocyte-platelet aggregates (MPA, expressed as percentage of monocytes binding platelets).

Results
Platelet CD41 were no different between three groups (p=0.84). Instead PAC-1 platelet expression, however, was increased in group NO-REFLOW compared to both group REFLOW (9.7±1.2 mfi vs 6.8±1.6 mfi; p=0.004) and stable CAD patients (6.2±1.4 mfi; p=0.001). Similarly, MPA were increased in group NO-REFLOW compared to both the group REFLOW (20.9±2.4% vs 14.6±3.8%; p=0.012) and stable CAD patients (10.1±1.2%; p<0.0001).

Conclusions
Platelet reactivity is increased at 1-month follow-up in AMI patients with evidence of no-reflow after successful coronary revascularization. This findings suggest that increased platelet reactivity might be involved in the mechanisms responsible for the no-reflow phenomenon.
Abstract 5582: Safety and Efficacy of Rivaroxaban in Prevention of Venous Thromboembolism in Patients Undergoing Elective Major Orthopedic Surgery: A Meta-Analysis of Randomized Controlled Trials
Authors: Tamhane Umesh U , Meier Pascal , Knapp Guido , Gurm Hitinder S
Published: April 2024

Background:
Venous thromboembolism is a significant cause of morbidity and mortality after major orthopedic surgery. Recent clinical trials comparing enoxaparin with rivaroxaban, a novel oral factor Xa inhibitor for thromboprophylaxis were not adequately powered to detect differences in low frequency clinical outcomes. We evaluated the impact of rivaroxaban in prevention of deep venous thrombosis (DVT) and pulmonary embolism (PE) compared to enoxaparin in patients undergoing elective total knee replacement (TKR) or total hip replacement (THR).

Methods:
Eight randomized trials (n=13398 patients) comparing rivaroxaban (10 mg/day) with enoxaparin therapy were included. Summary odds ratios for DVT, PE, deaths, major bleeding and cardiovascular events were calculated using random-effects models.

Results:
Rivaroxaban therapy was associated with a significant reduction in DVT (Odds ratio [OR] 0.49, 95% CI 0.33 – 0.75, p = 0.001). There was no significant difference in the incidence of PE (OR 0.90, 95% CI 0.30 –2.77, p = 0.86), deaths (OR 0.66, 95% CI 0.27–1.65, p = 0.38) or cardiovascular events (OR 0.91, 95% CI 0.50 –1.65, p = 0.76) during follow up for rivaroxaban compared to enoxaparin in THR and TKR populations. Major bleeding (OR 1.56, 95% CI 0.86 –2.83, p = 0.15) was also not significantly different between the two regimens.

Conclusion:
Rivaroxaban as a fixed once daily anticoagulant may be a more effective agent compared to enoxaparin for thromboprophylaxis in patients undergoing major orthopedic surgery.
Abstract 5586: Catestatin Induces Therapeutic Neovascularization by Induction of Angiogenesis and Incorporation of Endothelial Progenitor Cells
Authors: Theurl Markus , Schgoer Wilfried , Albrecht Karin , Beer Arno , Egger Margot , Vasiljevic Danijela , Tancevski Ivan , Schratzberger Peter , Patsch Josef , Mahata Sushil , Kirchmair Rudolf
Published: April 2024

Introduction
Catestatin (Cat), a biologically active fragment of Chromogranin A was described as a nicotinic antagonist inhibiting catecholamine release. Recently, also other biological effects for this peptide were described like release of histamine or activation during cutaneous wounds. We found that Cat induces chemotaxis on a variety of cells including endothelial cells (EC) and therefore hypothesized that Cat might act as a novel angiogenic cytokine.

Results
To investigate the effect of Cat on EC differentiation into vascular structures
in vitro
, we performed a matrigel tube formation assay using different concentrations of Cat. Cat at 10
−9
M was most effective in promoting tube formation (rel. tube form. 1.77+/−0.08 vs. ctr.; n=4, P<0.01). This effect could be blocked by a Cat antibody (Ab) (0.87 +/−0.1 vs. ctr; n=4, P<0.01 vs. Cat). Additionally, Cat dose-dependently induced chemotaxis of EC (rel. chemotact. index 10
−9
M: 1.67+/−0.03 vs. ctr; n=6, P<0.01) and promoted EC proliferation as measured by cell numbers of starved EC (rel. cell number 10
−9
M: 1.86 +/−0.13 vs. ctr., n=4, P<0.01; Cat-Ab 0.97+/−0.06 vs. ctr; n=4, P<0.05 vs. Cat). Western blot analysis revealed stimulation of ERK and AKT by 10
−9
M Cat indicating activation of these signal transduction pathways. We also tested for angiogenic effects
in vivo
by using 3 different mouse models. In the mouse cornea neovascularization model Cat induced significant growth of new blood vessels. In the unilateral limb ischemia model injection of Cat (10
μ
g every other day for 2 weeks) into adductor muscles increased capillary (475+/−31 vs. 303+/−28/mm
2
; n=7, P=0.003) and arteriole (10.1+/−0.8 vs. 5.2+/−1.0/mm
2
; n=7, P=0.001) density, and accelerated perfusion recovery as shown by LDPI (LDPI ratio ischemic/control leg after 28 days of ischemia) 0.94 vs. 0.74; n=10, P=0.009. Moreover, Cat treated mice showed more incorporated EPC in ischemic limbs using the actin-GFP bone marrow transplant model (21.7+/−2.2 vs. 9.6+/−2.1; n=6, P<0.001).

Conclusion
In summary our observations demonstrate that Cat therapy induces angiogenesis, arteriogenesis and vasculogenesis in the hind-limb ischemia model suggesting that Cat might be a promising agent for therapeutic angiogenesis in peripheral arterial disease.
Abstract 5587: Id1 Regulates Angiogenesis by Determining the Specification and the Timing of Notch Signaling
Authors: Nishiyama Koichi , Arima Satoshi , Ko Toshiyuki , Arima Yuichiro , Uchijima Yasunobu , Kurihara Yukiko , Ogawa Hisao , Kurihara Hiroki
Published: April 2024

Id1, a helix-loop-helix transcriptional factor, has emerged as a potent contributor of angiogenesis. We have previously reported that Id1 confers in vivo angiogenic property on human vascular endothelial cells (ECs) and that nucleo-cytoplasmic localization of Id1 might control angiogenesis. However, the downstream targets of Id1 and its interaction with other signaling pathways involved in angiogenesis are grossly unknown. To unveil the issue, we first examined the expression pattern of Id1 in ECs during angiogenesis in vitro and in vivo. We observed that Id1 expression levels were more prominent in sprouting ECs as compared with sheet-forming ECs at the proximal end of the sprouts in murine aortic ring assay. In the sprouts, furthermore, Id1 exhibited a mosaic expression pattern, mixed with weakly or no Id1-expressing ECs. We also identified similar expression pattern immunohistochemically in developing vessels of murine embryonic brain. Because the mosaic pattern of Id1 expression was reminiscent of Notch activation pattern in developing vessels, we next verified a possible crosstalk between Id1 and Notch signaling by RNAi-induced gene knockdown in cultured human ECs. Expectedly, siRNA-induced Id1-knockdown strikingly and specifically enhanced Notch-dependent upregulation of Hey2 (Gridlock) and to a less extent Hey1 but not Hes1. Id1-knockdown also upregulated the expression of a Notch-downstream effector Ephrin B2 in a Hey2-dependent manner. We finally examined how Id1 exhibited the mosaic expression pattern in ECs of developing vessels. Interestingly, Western blot analysis (hourly sampled for 12 hours) showed that total protein levels of Id1 appeared to oscillate periodically in cultured human ECs under confluent condition with no evident relation to cell cycle. This finding partially explains the mosaic expression pattern of Id1 during angiogenesis. Collectively, these results suggest a novel crosstalk between Id1 and Notch signaling, where Id1 might regulate the specification and the timing of Notch/Hey2 activation. We propose that the periodic expression of Id1 may be involved in the control of angiogenesis leading to proper branching morphology.
Abstract 5597: Transient Blockade of TGF-
β
in Hematopoietic Stem Cells and CD34+ Endothelial Precursor Cells Enhances Survival, Proliferation and Reparative Functions in Response to Ischemic Vascular Injury
Authors: Calzi Sergio Li , Bhatwadekar Ashay D , Afzal Aqeela , Caballero Sergio , Bartelmez Stephen , Pepine Carl J , Grant Maria B
Published: April 2024

Endothelial precursor cells participate in vascular repair; however in diabetes these cells can become dysfunctional. Previously, we showed that transient blockade of endogenous transforming growth factor-beta1 (TGF-beta1) by antisense phosphorodiamidate morpholino oligomers (PMOs) accelerated homing and engraftment of hematopoietic stem cells (HSC) in experimental models of bone marrow transplant. We asked whether transient blockade of TGF-beta1 could enhance mouse HCS and human CD34
+
-endothelial progenitor cell (EPC) recruitment and re-endothelialization to areas of vascular injury and correct vascular reparative defects of diabetic cells. Cells were treated with either control-PMO, anti-TGF-beta-PMO, or saline. Cell proliferation in response to the above treatments was studied in the colony forming assay for 1 week. CXCR-4 expression was examined by immunostaining and migration in response to stromal derived factor-1 (SDF-1) was tested using Boyden chamber assay. Mice were injected systemically with modified HSCs and then underwent either laser rupture of Bruch’s membrane to initiate choroidal neovascularization (CNV) or modified CD34
+
cells of diabetic and nondiabetic origin and then received the retinal ischemia reperfusion (I/R) injury. Neutralizing endogenous TGF-beta1 in cells sustained their survival in the absence of growth factors with no loss of proliferative potential. Pre-treatment with anti-TGF-beta-PMO increased expression of CXCR-4 in both diabetic and nondiabetic CD34
+
cells and increased their migration to SDF-1. HSC treated with anti-TGF-betaPMO demonstrated increased homing to CNV lesions and increased reendothelialization of acellular capillaries in the I/R model by both diabetic and nondiabetic cells. Blocking endogenous TGF-beta1 production by PMO induced increased CXCR-4 expression in cells and increased nitric oxide generation facilitating cell migration and enhanced vascular repair. Blocking TGF-beta1 in HSC/CD34
+
EPC may represent a novel therapeutic strategy in enhancing vascular repair in diabetes.

This research has received full or partial funding support from the American Heart Association, Greater Southeast Affiliate (Alabama, Florida, Georgia, Louisiana, Mississippi, Puerto Rico & Tennessee).
Abstract 5603: LL-37 Improves Adhesion and Therapeutic Effects of Embryonic EPCs in Chronic Ischemia (Rabbit Model)
Authors: Pfosser Achim , Hinkel Rabea , Stachel Georg , Trenkwalder Teresa , Hatzopoulos Antonis , Bals Robert , Kupatt Christian
Published: April 2024

Therapeutic neovascularization can be achieved by vascular growth factors or by mobilisation or exogenous application of endothelial progenitor cells. We could already demonstrate that murine embryonal EPCs (eEPCs) are capable of inducing therapeutic angiogenesis in a chronic hindlimb model (rabbit). Furthermore we could show that homing of these cells can be enhanced by transient overexpression of the pro-inflammatory transcription factor nfkb subunit p65. In the present study, we aimed at peptide activation of NF kappa b in the eEPC population. For this purpose, we used the cathelicidin (LL-37), which binds to the receptor FPRL1 subsequently activating NF kappa B.

Methods: Adhesion of wildtype (wt), p65 transfected (p65t) and LL37-activated eEPCs (100
μ
g, LL37-eEPC) was examined in vitro in flow chamber experiments. In rabbits, at d7 after femoral artery excision, 5×106 eEPCs (n=5 per group) were retroinfused into the anterior tibial vein. At d7 and 35 angiography of both hindlimbs was performed for collateral quantification and frame count score (cinedensitometry, % of d7 level each). Capillary/muscle fiber (C/MF) ratio was assessed at d35.

Results: eEPC adhesion was more than doubled after pre-treatment with LL-37 (326±13 cells/field vs. 153±19, wt). In vivo, no difference was found in C/MF ratio of p65t-eEPC- or wt-eEPC-treatment (1,44±0.10 vs. 1.41±0.09, respectively), whereas LL-37-eEPC treated animals showed a significant effect (1,93±0,13). Collateral growth (wt-eEPCs 129±5% vs. 109±4% in controls), was elevated by p65t-eEPCs (146±4%), and further increased in LL37-ePCs (179±8%). The wt-eEPC-induced gain of perfusion (151±5% vs. 109±10% in controls) was similarly improved by p65t-eEPC transfusion (205±24%) and LL-37-preincubation (244±22%). We conclude that induction of a pro-inflammatory phenotype in eEPCs by either transient p65 transfection or LL37 enhances recruitment and subsequent neovascularization in ischemic tissue.
Abstract 5605: Significant Reduction of Hospital Mortality of Stemi in Clinical Practice 1994–2008 Through Improvement of Guideline Adherence: Results of MITRAplus and OPTAMI
Authors: Gitt Anselm K , Zeymer Uwe , Zahn Ralf , Juenger Claus , Senges Jochen
Published: April 2024

Background: Data from national and international myocardial infarction registries have identified the gaps between recommendations of guidelines for the management of ST-elevation myocardial infarction (STEMI) and treatment in clinical practice. Participation in continuous STEMI registries with benchmarking reports to the centres might improve implementation of guidelines into practice.

Methods: Between 1994 and 2008, 37,876 consecutive patients with STEMI were enrolled into the MI-registries MITRAplus and OPTAMI to document patients’ characteristics, acute treatment and outcome in clinical practice. We examined the impact of guideline adherence for acute treatment of STEMI including reperfusion as well as adjunctive medical treatment on hospital outcome over time in Germany 1994 –2008.

Results: From 1994 to 2008, the rate of acute reperfusion therapy in Germany increased from minimal 49% to 90% of consecutive patients with STEMI in 2008 with a significant shift from fibrinolysis to primary PCI. In parallel, the use of adjunctive medical treatment with aspirin, beta-blockers, ACE-inhibitors and clopidogrel was significantly improved over time. This improvement of guideline adherence for the acute treatment of STEMI was associated with a significant reduction of hospital mortality from initially 16.2% in 1994 to 6.2% in 2008.

Limitation: In the currently conducted OPTAMI-Registry, 84% of participating centres provide 24h PCI-service. The data from 2006 –2008 therefore reflects the treatment and outcome of STEMI in tertiary centres in Germany, but clearly demonstrates that implementation of current practice guidelines is feasible.

Conclusion: The improvements of guideline adherence for the management of STEMI, especially the increased rates of primary PCI as well as acute adjunctive medical treatment were associated with a significant decrease of hospital mortality in clinical practice in Germany.
Abstract 5650: Interactions Between the Endogenous NO Synthase Inhibitor Asymmetric Dimethylarginine and the Leukocyte-derived Hemoprotein Myeloperoxidase
Authors: Sydow Karsten , von Leitner Eike-Christin , Maas Renke , Klinke Anna , Schwedhelm Edzard , Kielstein Jan T , Atzler Dorothee , Lau Denise , Ehmke Heimo , Meinertz Thomas , Willems Stephan , Böger Rainer H , Baldus Stephan
Published: April 2024

Background: ADMA and the NO oxidizing leukocyte-derived hemoprotein MPO are associated with cardiovascular diseases. ADMA and MPO per se coincide with increased oxidative stress and induction of inflammatory responses. Furthermore, the enzymes responsible for ADMA homeostasis (i.e. dimethylarginine dimethylaminohydrolase, DDAH) are regulated in a redox-sensitive fashion. Therefore, the aim of the study was to investigate whether there is an interaction between ADMA and MPO resulting in increased leukocyte (PMN) activation and reduced NO bioavailability.

Methods: To test a direct leukocyte activating effect of ADMA, isolated human PMN were subjected to ADMA, SDMA, and fMLP -an inductor of NADPH oxidase activity- to determine PMN degranulation (MPO activity, MPO and elastase levels) and leukocyte superoxide production. NO synthase and DDAH activity was measured by GC-MS and LC-MS/MS, respectively. In vivo, the effect of chronic ADMA (250
μ
mol/kg/d; 28 days) treatment on MPO concentrations was induced by osmotic minipumps in C57 mice. To test the effect of MPO on DDAH1 and -2 gene expression, taqman rtPCR technique was performed in liver and kidney tissue of MPO knockout mice. The effect of MPO on DDAH activity in vitro was studied using a recombinant DDAH enzyme.

Results: ADMA and fMLP incubation -but not SDMA- significantly increased superoxide production, PMN degranulation and MPO release. Furthermore, ADMA but not SDMA was able to impair NO synthesis of PMN and enhanced PMN’s adhesion to cultured HUVECs in vitro. In vivo, chronic treatment with ADMA resulted in a significant increase of plasma MPO concentrations in C57 mice in contrast to vehicle-treated controls. DDAH1 gene expression was markedly increased in liver and kidney tissue of MPO knockout mice compared to C57 controls. In vitro, MPO and its product HOCl were able to impair recombinant DDAH activity, whereas inactivated MPO was not.

Summary and conclusions: ADMA profoundly activates PMN resulting in increased degranulation and MPO release, superoxide production, and impaired NO synthesis. MPO modulates DDAH expression and impairs DDAH activity. Our data revealed a two-way interaction between the ADMA and MPO pathway, which may open a new avenue for treatment of cardiovascular disease.
Abstract 5656: Anticentromere Antibody Increases ICAM-1 Expression and Monocyte Adhesion in Pulmonary Endothelial Cells: Implications for Scleroderma-Associated Pulmonary Hypertension
Authors: Nakhla Shirley , Ilsar Rahn , Heather Alison K , Celermajer David S
Published: April 2024

BACKGROUND: Scleroderma is characterized by the presence of high circulating levels of anticentromere antibody (ACA) and is commonly complicated by pulmonary hypertension (PHT). We hypothesized that ACA may alter pulmonary endothelial cell function.

METHODS: Human pulmonary microvascular endothelial cells (HPMvECs) were treated with ACA (0.25 – 1.0 mg/mL, equivalent to serum titers of 1:320 – 1:2560) and IgG controls. Monocyte adhesion to HPMvECs was measured by automated cell count and cell adhesion molecule expression (ICAM-1 and VCAM-1) was assessed by flow cytometry (protein) and RT-PCR (mRNA). Promoter activity was assessed by luciferase reporter vector in HPMvECs and human umbilical vein endothelial cells (HUVECs). ACA uptake into HPMvECs was assessed by fluorescent microscopy.

RESULTS: Fluorescently labeled ACA was shown to penetrate HPMvECs within 10 min. ACA increased ICAM-1 protein levels in a dose-dependent manner (118±11, 132±8 & 162±7% increase vs control (100%) for 0.50, 0.75 & 1.0 mg/mL respectively, P < 0.0001, n=5; Fig

). No effect was observed for VCAM-1. ICAM-1 increases were associated with enhanced monocyte adhesion to endothelial cells (211±9%, 1.0 mg/mL vs control, P < 0.0001, n=3). ICAM-1 mRNA levels were markedly increased by ACA (745±113%, 1.0 mg/mL vs control, P < 0.0001, n=4). ACA did not affect ICAM-1 mRNA stability but increased ICAM-1 promoter activity (136±9% & 148±12%, 1.0 mg/mL vs control for HPMvECs & HUVECs respectively, P < 0.01, n=3).

CONCLUSION: ACA increases HPMvECs ICAM-1 expression and monocyte cell adhesion. These findings may implicate a role for ACA in the development of PHT in scleroderma.
Abstract 5657: Growth Differentiation Factor-15 as a Biomarker in Pulmonary Arterial Hypertension and Hypoxia-induced Pulmonary Hypertension
Authors: Rhodes Christopher J , Wharton John , Howard Luke , Gibbs J Simon R , Aldashev Almaz A , Wilkins Martin R
Published: April 2024

Circulating growth differentiation factor (GDF)-15 is a possible biomarker in idiopathic pulmonary arterial hypertension (IPAH). We sought to verify its prognostic value and evaluate GDF-15 in other forms of pulmonary hypertension (PH). GDF-15 and N-terminal pro-brain natriuretic peptide (NT-proBNP) were assayed in 127 IPAH patients, 83 of whom received targeted therapy. GDF-15 was also measured in 16 connective tissue disease-associated PAH (CTD) patients, 64 healthy controls and 89 Kyrgyz highlanders (2500 –3600 m), 35 of whom had PH (HAPH; mean pulmonary artery pressure (mPAP) >25 mmHg). GDF-15 levels were greater in IPAH (mean±SEM 987 ±81 pg/ml) and CTD (978 ±144 pg/ml) versus controls (306 ±16 pg/ml; P<0.001). GDF-15 levels >800 pg/ml were associated with decreased exercise capacity (p=0.002) and cardiac index (p=0.02), and increased NT-proBNP (p<0.001), age (p<0.001) and mean right atrial pressure (p=0.02), but did not correlate with mixed venous or arterial (SaO
2
) oxygen saturation. 3 year mortality in IPAH was 21% (GDF-15 <800 pg/ml) and 58% (GDF-15 >800 pg/ml), with a hazard ratio of 5.12 (95% CI 1.89 –13.9; P<0.001). GDF-15 remained an independent predictor of mortality after adjusting for clinical/haemodynamic measurements and combining NT-proBNP data improved risk stratification. SaO
2
was significantly lower in high altitude (90.4±0.4%) and HAPH subjects (87.3±0.7%) versus IPAH patients (93.3±0.6%; P<0.001). GDF-15 was raised in HAPH, not high altitude residents (548±64 vs. 307±14 pg/ml; P<0.001), and correlated with mPAP (p<0.001). The data support the use of GDF-15 as a prognostic marker in IPAH and question whether hypoxia stimulates GDF-15 in PH.
Abstract 5664: Circulating Soluble Endoglin is a Sensitive Predictor of Pulmonary Arterial Hypertension and Exercise Function
Authors: Yu Paul B , Zamanian Roham T , Malhotra Rajeev , Schmidt Jonathan , Deng Donna Y , Lai Carol S , Parker William , Bloch Kenneth D , Elliott C. Gregory
Published: April 2024

Rationale

: Circulating biomarkers of inflammation and endothelial dysfunction are sensitive for the presence of systemic vascular disease and may aid in the early assessment of pulmonary arterial hypertension (PAH). Current biomarkers for PAH such as NT-proBNP provide useful prognostic data but detect ventricular strain associated with advanced or severe disease.

Objectives

: We tested the hypothesis that circulating protein markers of endothelial dysfunction or inflammation – soluble endoglin (sEng), osteoprotegerin (OPG), high-sensitivity C-reactive protein (hsCRP) and interleukin 15 (IL-15) – may predict the presence or severity of PAH.

Methods

: Circulating protein levels were measured by immunoassay in a total of 84 individuals: 42 with WHO diagnostic group 1 PAH of various etiologies (see table

), 11 of their first-degree relatives, and 31 healthy age- and gender-matched controls.

Measurements and Main Results:

Circulating levels of sEng, hsCRP, OPG, and NT-proBNP were significantly elevated in PAH patients versus controls, whereas IL-15 levels were elevated only in PAH associated with connective tissue disease (p<0.001). sEng was superior to NT-proBNP for predicting PAH by receiver operating characteristic analysis (p=0.015). A sEng threshold of 3.7 ng/ml had a sensitivity of 86% and specificity of 74% for the presence of PAH, compared to a sensitivity of 70% and specificity of 74% for an NT-proBNP threshold of 180 pg/ml. Moreover, sEng levels correlated inversely with six minute walk distances (r=−0.48, p<0.05).

Conclusions

: Serum markers of inflammation or vascular dysfunction are sensitive predictors for the presence of PAH of all etiologies and in the case of sEng correlate with reduced exercise capacity. Levels of IL-15 are elevated in PAH associated with connective tissue disease. Markers of inflammation may be more sensitive for PAH than those of ventricular strain and may provide unique noninvasive data.

Biomarker levels in controls, PAH patients, and 1st degree relatives
Abstract 5767: Viral Anti-inflammatory Treatment of Unstable Coronary Syndromes: The VT-111 Acute Coronary Syndrome Trial
Authors: Tardif Jean-Claude , L’Allier Philippe , Grégoire Jean , Ibrahim Reda , McFadden Grant , Kostuk William J , Knudtson Merril L , Labinaz Marino , Waksman Ron , Pepine Carl J , Macaulay Colin , Lucas Alexandra
Published: April 2024

Background:
Up-regulation of inflammatory responses contributes to coronary plaque rupture, thrombosis, and vascular occlusion leading to myocardial and cerebral infarction. Some viruses have developed potent proteins that block key steps in both the innate and adaptive immune responses. VT-111 is a viral serine proteinase inhibitor that demonstrates reductions in monocyte migration to sites of vascular damage in a wide range of animal models.

Methods:
In a double-blind, placebo-controlled trial, the safety of VT-111 plus standard of care was evaluated in patients with acute coronary syndromes treated with stents. Patients received IV VT-111 or placebo once daily for 3 days, starting immediately before intervention. Patients were followed for 3 days in hospital, and at 14, 28 days and 3 and 6 months for safety/efficacy endpoints, including biomarker analysis and MACE (death, MI or revascularization). At 6 months, restenosis was evaluated by intravascular ultrasound.

Results:
Forty-eight patients were enrolled at 7 sites; 19 patients received 5
μ
g/kg VT-111, 17 patients received 15
μ
g/kg and 12 patients received placebo. There were no differences between the treated and control groups on key safety endpoints, including coagulation parameters and adverse events. A trend towards a decrease in MACE was observed, with a reduction to 0% in the 15
μ
g/kg group from 18% in controls. A significant, dose-dependent reduction in Troponin I levels was observed with VT-111 at 8, 16, 24 and 54 hours post-dose (p<0.05). Similar reductions were observed in CK-MB levels at 8, 16 and 24 hours post-dose (p<0.05). Trends towards a reduction in MCP-1 were also observed. Further analysis suggests that VT-111 may also have early effects on markers such as EN-RAGE (S100A12), IL-6 and CD40L. There were no differences in in-stent plaque area or lumen area between control and treated groups, as assessed by IVUS.

Conclusion:
This randomized, placebo-controlled trial supports the safety of 3 daily IV injections of VT-111, a first in class viral-derived anti-inflammatory therapeutic agent. A significant reduction in biomarkers of cardiac damage demonstrates the potential of this novel class of protein therapeutics.
Abstract 5774: Hypoxia Enhances Platelet-derived Growth Factor Signaling in the Pulmonary Vasculature by HIF-1
α
-dependent Downregulation of Protein Tyrosine Phosphatases
Authors: Freyhaus Henrik , Leuchs Maike , Dagnell Markus , Vantler Marius , Caglayan Evren , Weissmann Norbert , Schermuly Ralph T , Dahal Bhola K , Östman Arne , Kai Kappert , Rosenkranz Stephan
Published: April 2024

Background: Platelet-derived growth factor (PDGF) plays a critical role in the development of pulmonary hypertension (PH) as it promotes pulmonary vascular remodeling. PH is frequently associated with severe pulmonary hypoxia. Here we investigated whether hypoxia alters PDGF
β
receptor (
β
PDGFR) signaling.

Methods and Results: Chronic hypoxia enhanced PDGF-BB-dependent proliferation and chemotaxis of human pulmonary arterial smooth muscle cells (hPASMC). Pharmacological inhibition of PI3 kinase (PI3K) and PLC
γ
abrogated these events both under normoxia and hypoxia. While hypoxia did not affect
β
PDGFR expression, it increased the ligand-induced tyrosine phosphorylation of the receptor, particularly at the binding sites for PI3K (Y751) and PLC
γ
(Y1021). The activated
β
PDGFR is dephosphorylated by protein tyrosine phosphatases (PTPs). Strikingly, hypoxia decreased the expression of numerous PTPs (TC-PTP, DEP-1, PTP1B, SHP-2), resulting in reduced PTP activity. Putative hypoxia-inducible factor (HIF)-1
α
binding sites were identified in the promoter regions of the downregulated PTPs, and hypoxia-induced
β
PDGFR hyperphosphorylation and PTP downregulation were abolished by HIF-1
α
siRNA and by the HIF-1
α
inhibitor 2-methoxyestradiol. Immunohistochemistry and quantitative RT-PCR demonstrated that
β
PDGFR hyperphosphorylation and PTP downregulation were also present in vivo in mice with chronic hypoxia-induced PH.

Conclusions: Hypoxia reduces the expression and activity of
β
PDGFR-antagonizing PTPs in a HIF-1
α
-dependent manner, thereby enhancing receptor activation and proliferation/chemotaxis of hPASMC. As hyperphosphorylation of the
β
PDGFR and downregulation of PTPs also occur in vivo, this mechanism likely has significant impact on the development and progression of PH and other proliferative diseases.
Abstract 5783:
β
-Arrestin-Dependent Activation of Ca
2+
/Calmodulin-Dependent Kinase II Following
β
1
-Adrenergic Receptor Activation
Authors: Mangmool Supachoke , Zou Weili , Mao Lan , Rockman Howard A
Published: April 2024

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 5794: Clinical Risk Factors to Predict Deep Venous Thrombosis Post Endovenous Laser Ablation of Saphenous Veins
Authors: Chi Yung-Wei , Ali Lobna , Woods T. Cooper
Published: April 2024

Introduction: Endovenous laser ablation of saphenous veins is an alternative to standard surgical vein stripping for the treatment of symptomatic varicose veins. Deep venous thrombosis (DVT) has been reported as a complication of such procedure with a rate of 1 to 5 %. Clinical risk factors to predict DVT post endovenous laser ablation are not well established.

Hypothesis: To establish clinical risk factors to predict DVT post endovenous laser ablation.

Method: Three hundred sixty consecutive patients who underwent endovenous laser ablation of saphenous veins were followed. Duplex ultrasound was performed within 1 week of the index procedure. DVT was defined as evidence of non-compressibility involving the sapheno-femoral, sapheno-popliteal junctions or any of the deep veins. Comparison between those with and without DVT was performed using step-wise logistic regression (SAS, SAS Institute, Cary, NC) to measure the correlation between continuous and categorical variables. The continuous variables included age, weight, glomerular filtration rate, distance of laser ablation, total energy used and the categorical variables included gender, diabetes mellitus, hypertension, hyperlipidemia, prior stroke, superficial venous thrombosis (SVT), DVT, coronary artery disease, peripheral arterial disease, and pulmonary embolism. Additional iterations were performed to determine the predictive power of various age thresholds. A p value < 0.05 was accepted as representing a significant difference.

Result: Nineteen DVTs were found on follow up ultrasound. Eighteen cases involved either the sapheno-femoral or sapheno-popliteal junctions. Only one case involved the deep venous system. Age > 66 (p = 0.007), female gender (p = 0.048) and prior history of SVT (p = 0.002) were associated with increased risk of DVT post endovenous laser ablation.

Conclusion: Age > 66, female gender and history of prior SVT are risk factors to predict DVT post endovenous laser ablation.

Clinical Risk Factors to Predict DVT Post Endovenous Laser Ablation
Abstract 5800: Angiopoietin-2 Induced Left Ventricular Hypertrophy is Reduced by AAV-mediated Angiopoietin-1 Overexpression
Authors: Horstkotte Jan , Schwab Claudia , Ziegler Tilman , Schroeder Melanie , Hinkel Rabea , Kieu Cuong , Deutsch Urban , Kupatt Christian
Published: April 2024

Angiopoietin-2 (Ang-2), a co-factor in postnatal angiogenesis interacting at the endothelial Tie-2 receptor, is a potential target for therapeutic angiogenesis. Though antagonistic functions of Ang-2 and Angiopoietin-1 (Ang-1) have been described, the impact of long lasting Ang-2 expression on cardiac function has not been characterized. Here we analysed the impact of chronic Ang-2 overexpression and interaction with Ang-1 on myocardial morphology and function using a AAV2.9-vector overexpressing Ang-1 (rAAV-Ang-1).

Methods: For this purpose conditional Ang-2 overexpressing mice (Tet-off transgenic mice, under control of Tie2-promoter = Ang2-tg) were established and analyzed by echocardiography, non-invasive heart rate (HR), mean arterial pressure (MAP) and invasive catheterization.

Results: Ang2-tg mice displayed a significant cardiac dilation from 12 wks to 24 wks of age (LV-EDD: Ang2-tg: 0,47±0,02cm, control: 0,39±0,01cm, n=18). Application of doxycycline (Dox) or transfection of rAAV-Ang-1 (Ang2-tg+rAAV-Ang1) reversed the phenotype almost entirely (Ang2-tg+Dox: 0,43±0,01cm, Ang2-tg+rAAV-Ang1: 0,40±0,02cm, control 0,40±0,01cm), while absence of treatment resulted in progressive cardiac dilation (Ang2-tg: 0,55±0,04cm). Furthermore Ang2-tg mice revealed increased heart weight (hw) normalized to body weight (bw) (hw/bw) mg/g. (Ang2-tg: 8,0±1,5, control: 5,2±1,2). Hypertrophy was not observed in Dox or rAAV-Ang1 treated animals. In addition increased HR and reduced MAP shown in Ang2-tg-mice (HR: 615±43bpm, MAP: 84±3mmHg) normalized in Dox-treated (HR: 542±69bpm, MAP:102±9mmHg) or rAAV-Ang1 transfected animals (HR: 506±62bpm, MAP:94±4mmHg) to control level (HR: 545±36bpm, MAP:95±2mmHg). Invasive data confirmed these findings.

Summary: Our results indicate that prolonged Ang-2 overexpression induces progressive LV-dilation and myocardial dysfunction. The cardiac morphology at 12 wks is reversible, if Ang-2 overexpression is shut off, or antagonised by or Ang-1 upregulation. It is tempting to speculate that Ang-2 affects the vascular system profoundly, forcing reactive dilation and cardiac dysfunction.
Abstract 16645: Abcc9 Contributes to Mitochondrial Katp Function and Protection From Cardiomyopathy
Authors: Fahrenbach John , Stoller Douglas , Kim Gene , Aggarwal Nitin , Yerokun Babatunde , Earley Judy , Hadhazy Michele , Shi Nian-Qing , Makielski Jonathan , McNally Elizabeth
Published: April 2024

In response to intracellular energy supply, ATP-sensitive potassium (KATP) channels alter membrane potential and mediate cell stress response. The
Abcc9
gene encodes the major regulatory subunit in the heart, sulfonylurea receptor 2 (SUR2), as well as smaller mitochondria-enriched proteins that contribute to sulfonylurea-insensitive KATP channels. Pharmacological studies suggest mitochondrial KATP channels are critical regulators of cell stress, however the molecular composition of this channel has been unclear. We now studied the role of KATP channels by deleting exon 5 of
Abcc9
. This strategy ablated expression of both full length SUR2 protein as well as the smaller mitochondrial 55 KDa protein. Homozygous exon 5 (Ex5) mice died within 14 days of birth with progressive cardiac contractile dysfunction. Diazoxide was found to depolarize mitochondria from wildtype cardiomyocytes but not Ex5 mitochondria, consistent with disrupted mitochondrial KATP channels. Ex5 mitochondria had a reduced cross sectional area (WT: 1.27±0.11 vs. Ex5: 0.67±0.04µm
2
, p<0.05), and Ex5 cardiomyocytes also exhibited reduced oxygen consumption(WT: 1.86±0.41 vs. Ex5: 0.61±0.14nmO
2
/s, p<0.05). Deletion of exons 14 to 18 in
Abcc9
disrupts full length SUR2 but leaves intact the 55 KDa protein. To determine the contribution of the mitochondrial 55 KDa protein, we compared the ability of Ex14/18 and Ex5 cardiomyocytes to withstand H2O2-induced stress. H
2
O
2
application resulted in a more rapid collapse of mitochondria membrane potential in Ex5 mitochondria (5.2±0.3s) compared to wildtype (15.1±0.6s) and Ex14/18 (13.1±0.6s) mitochondria. We conclude the
Abcc9
-encoded 55 KDa protein contributes to mitochondrial KATP channels, and that mitochondrial KATP channels mediate the acute stress associated with cardiac function in the neonatal window.
Abstract 16670: Anterior Myocardial Infarction and Low Ejection Fraction: Should We Anticoagulate?
Authors: Buss Nicholas , Friedman Scott , DeVries James
Published: April 2024

Introduction:
Left ventricular (LV) thrombus formation is a recognized complication in patients with anterior STEMI. Warfarin is often used in this setting to prevent thrombus formation despite limited data to support this practice. We sought to determine the incidence of LV thrombus formation and assess the clinical benefit of anticoagulation for prophylaxis against LV thrombus and ischemic stroke in patients presenting with anterior STEMI and reduced ejection fraction (EF) who were treated with early reperfusion therapies and dual antiplatelet agents.

Methods:
Consecutive patients (N=298) with anterior STEMI and low post-infarct EF (<40%) presenting to a single center between 2001 and 2010 were identified using an institutional registry. Patient demographics, presence of LV thrombus, anticoagulation strategy, and clinical outcomes at 6 months were determined using chart review. Patients with thrombus on the initial post-infarct echocardiogram were excluded (N=26). The primary outcomes were bleeding, stroke, and death within 6 months of the infarct.

Results:
LV thrombus occurred in 8.7% of patients with anterior STEMI and EF <40%. The incidence of clinically relevant bleeding was 13.2% and ischemic stroke was 2.2%.There was no significant difference in the rates of bleeding, stroke, or death based on treatment with warfarin (see table). There were four fatal bleeds, all occurring in patients on warfarin therapy.

Conclusions:
The incidence of LV thrombus in this high-risk group of patients with anterior STEMI and reduced EF is approximately 9%. The rate of ischemic stroke at 6 months was not affected by the addition of warfarin to dual antiplatelet therapy. In conclusion, the rate of thrombus formation and ischemic stroke were low, while the rate of clinically relevant bleeding was relatively high, suggesting that the routine use of warfarin for prophylaxis is not warranted.
Abstract 16690: Transcatheter Aortic Valve Implantation (TAVI): A Five Year Single-Center Experience
Authors: Al-Rashid Fadi , Thielmann Matthias , Patsalis Polykarpos-Christos , Neumann Till , Konorza Thomas , Wendt Daniel , Jakob Heinz , Erbel Raimund , Kahlert Philipp
Published: April 2024

Background:
Transcatheter aortic valve implantation (TAVI) has evolved to an accepted treatment option for high-risk patients with severe aortic stenosis. We report our five year experience comparing transfemoral (TF) and transapical (TA) TAVI using the the balloon-expandable Edwards and the self-expandable Medtronic-CoreValve (MCV) prosthesis.

Methods:
From 01/2006 to 05/2011, 329 high-risk patients underwent TAVI (TF: n=223 [Edwards n=135; MCV n=98]; TA: n=106). We analysed procedural data and outcome of this cohort.

Results:
Patients undergoing TA-TAVI were older (82±4 vs. 80±6yrs; p=0.071) and significantly sicker than TF-TAVI patients (EuroScore 33±15% vs. 19±13%; p<0.001). Procedural success was achieved in all but four patients (TF: n=2; TA n=2, p=0.740) .We found a non-significant trend towards a higher 30-day mortality (11% vs. 8%, p=0.270) and cumulative mortality in the sicker TA-TAVI patient cohort (figure 1). Interestingly, in both groups there was an apparent learning curve which was reflected in a significantly better survival (30-day mortality: TF: 18%vs.8%; p=0.034; TA: 31%vs.8%; p=0.003) in the second half of each group (figure 2). There was no signifcant difference between the Edwards and Corevalve prosthesis in the transfemoral approach. Long term mortality was mainly due to non-cardiac deaths.

Conclusion:
TAVI can be performed with high procedural success rates after an inherent learning curve. As expected by different baseline characteristics, TA-TAVI patients had a higher mortality than TF-TAVI patients. Overall, the five year data show positive results of this novel treatment.
Abstract 16695:
O
-GlcNAc Cycling Enzymes and Myofilaments in Diabetic Cardiomyopathy: An Increased Association Leading to Myofilament Ca
2+
Desensitization
Authors: Ramirez Genaro , Slawson Chad , Zeidan Quira , Ding Wengang , Shen Xiaoxu , Gao Wei D , Caceres Viviane , Paolocci Nazareno , Hart Gerald W , Murphy Anne M
Published: April 2024

Protein O-GlcNAcylation, the addition of a single β-D-N-acetylglucosamine (GlcNAc) to serine/threonine residues, by OGT (O-GlcNAc transeferase) and removal by OGA (O-GlcNAcase), is a post-translational modification that regulates cardiovascular function. Regulation of O-GlcNAcylation serves as a metabolic/nutrient sensor, and is disrupted in diabetes. We hypothesize that altered O-GlcNAcylation of myofilament proteins is an important molecular mechanism that contributes to myofilament Ca
2+
desensitization in diabetes. To test the role of O-GlcNAc in this process we enzymatically removed endogenous O-GlcNAcylation in cardiac skinned fibers from normal and diabetic type 1 rats
via
a homologue of human OGA (CpNagJ). We found that removing endogenous O-GlcNAc restored myofilament response to Ca
2+
only in streptozotocin (STZ)-induced type 1 diabetic rat muscles (ECa
50
4.17±0.48 µM STZ Pre- CpNagJ vs. 2.73±0.22 µM STZ Post- CpNagJ,
n
=5
vs. n
=4, p=0.029), whereas in control muscles it had no effect. Similarly, maximal Ca
2+
activated force (F

max

) and myofilament cooperativity (
n
Hill), remained unchanged after CpNagJ treatment in both groups. Immunoprecipitation experiments in normal and diabetic hearts uncovered OGT and OGA interactions with MyBP-C, α-actin, tropomyosin, and myosin light chain 1. Except for MyBP-C, these protein interactions were increased in the diabetic hearts. In normal myocytes, confocal and immuno-electron microscopy analyses, illustrated OGT and OGA compartmentalization at the Z-disk and A-band, respectively. Strikingly, analysis of their ultra-structural distribution reveal that in the diabetic myocardium OGT and OGA compartmentalization was lost, with both proteins exhibiting a more diffuse localization and increased immuno-staining. Moreover, OGT and OGA were readily detected within mitochondria, and OGT immuno-staining was elevated in diabetic mitochondria. Our data demonstrate that removal of endogenous myofilament O-GlcNAcylation, specifically from diabetic muscles, restores myofilament Ca
2+
sensitivity to normal. This suggests that altered GlcNAc “cycling” plays a key mechanistic role in the abnormal myofilament response to Ca
2+
in diabetic cardiac muscle.
Abstract 167: Barriers to Adoption of Postarrest Therapeutic Hypothermia and Methods to Increase Implementation
Authors: Blewer Audrey L , Leary Marion , Delfin Gail , Gaieski David F , Merchant Raina M , Becker Lance B , Abella Benjamin S
Published: April 2024

Background:
Post-arrest therapeutic hypothermia (TH) has been shown to dramatically improve outcomes after resuscitation, yet studies have revealed that TH adoption has been inconsistent and slow. Little is known about barriers to TH implementation and methods to increase adoption.

Objective:
We hypothesized that lack of education surrounding implementation is a more important barrier to TH adoption than lacking institutional leadership support or physician acceptance, and that an educational intervention might increase TH use.

Methods:
We administered mixed quantitative/qualitative surveys to clinicians before and after enrollment in a series of TH educational courses from 10/2009 to 7/2011, to determine usage and barriers to implementation. Six months post-training, self-reported clinician confidence and use of TH was assessed in the same cohort.

Results:
Clinicians completed 160 surveys (81 pre-training and 79 post-training). Of those, 74% were nurses, 24% were physicians; most represented ICU or ED practitioners. A ranking survey (score range 1-7; 7 as most important) found that lack of adequate staffing (mean score 4.5+2.1) and adequate education (4.4 + 1.6) were the two most emphasized barriers to TH implementation. Lacking institutional leadership support or physician acceptance was the least emphasized barrier (2.5+1.6, 3.3+2.0 respectively). Mean scores were significantly different between the expressed lack of adequate education and either institutional support or physician acceptance (p<0.01, p=0.02, respectively). Post-survey results found that 96% of respondents felt more confident initiating TH post-educational intervention. There was a statistically significant increase in self-reported TH usage by surveyed clinicians after participation in our TH educational programs (p<0.01).

Conclusions:
Practitioners highlighted lack of education surrounding TH implementation as a key barrier to TH use. A focused TH training course led to increased confidence and TH usage among participants. Future work will focus on targeted training to address specific barriers and increase appropriate TH utilization.