bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1473: Cardiac Targeted Transgenic Models of Mutations in TK2 or Pol γ Genes Result in Ultrastructural Changes in Mitochondria and Cardiac Hypertrophy
Authors: Kohler James J , Hosseini Seyed , Day Brian , Saada Ann , Elpeleg Orly , Copeland William , Lewis William
Published: July 2021

Background:
Mitochondrial (mt) biogenesis and homeostasis of precursor pools are critical to normal cardiac performance. Two important enzymes are involved in mtDNA replication. DNA polymerase gamma (Pol γ) is responsible for replication of mtDNA. Thymidine kinase 2 (TK2) is responsible for intramitochondrial monophosphorylation of pyrimidines. Point mutations in Pol γ and TK2 identified in mitochondrial genetic diseases include human chronic progressive external opthalmoplegia (CPEO) associated with a Pol γ Y955C mutation, while His121Asn (HIS) and Ile212Asn (ILE) mutations in TK2 result in heritable mtDNA depletion syndromes with organ dysfunction. Because nucleoside reverse transcriptase inhibitors (NRTI) can also disrupt mtDNA replication, we examined the impact of cardiac-targeted transgenic overexpressors of Pol γ or TK2 mutants in combination with NRTI-based HAART on cardiac function.

Methods:
Targeted transgenic mice (TG) were generated that overexpress Y955C, HIS or ILE in cardiac tissues driven by the α-MyHC promoter. Changes in cardiac and mitochondrial structure and function were examined by echocardiography (ECHO), transmission electron microscopy (EM), mtDNA abundance, 8-OH2dG and SDH enzyme histochemistry quantitation. TGs and wild-type (WT) littermates were treated with vehicle or NRTI-based HAART (ziduvodine, lamivudine, and indinavir, 35 days).

Results:
Y955C TGs had decreased cardiac mtDNA abundance, increased mitochondrial oxidative stress (increased 8-OH2dG), and mitochondrial destruction together with increased LV mass. HIS TGs (both treated and untreated) demonstrated increased LV mass and a 2-fold increase in mtDNA abundance compared to WT. Untreated ILE TGs had no analogous impact, but the addition of HAART treatment resulted in increased LV mass and mtDNA abundance.

Conclusions:
Inefficient mtDNA replication and mitochondrial oxidative stress contribute to mtDNA depletion. Pol γ Y955C and TK2 HIS each alters mtDNA replication. ILE had minimal impact on mitochondrial ultrastructure or cardiac function, but together with HAART had an effect. These pathogenic point mutations in genes involved in mtDNA replication may increase risk for cardiac hypertrophy compounded by NRTI treatment.
Abstract 1490: The Targeting Of Cyclophilin D By RNA Interference As A Novel Therapeutic Strategy Against Myocardial Ischemia/Reperfusion Injury
Authors: Kato Masashi , Akao Masaharu , Makiyama Takeru , Matsumoto-Ida Madoka , Iguchi Moritake , Takeda Toshihiro , Kita Toru
Published: July 2021

Background-

An opening of the mitochondrial permeability transition pore (MPTP), which leads to loss of mitochondrial membrane potential (ΔΨ
m
) and mitochondrial dysfunction, is the earliest event that commits cells to death, and this process is potentially a prime target for therapeutic intervention against myocardial ischemia/reperfusion. We examined the effects of genetic knock-down of cyclophilin D (CypD), one of the putative components of MPTP, using RNA interference.

Methods and Results-

We created an adenovirus carrying short interfering RNA (siRNA) which inactivates CypD. Transduction of siRNA-CypD in cultured neonatal rat cardiomyocytes achieved 68% reduction in mRNA and 61% reduction in protein levels, and suppressed cell death induced by H
2
O
2
(100μM) as assessed by cell viability assay. It also protected against ΔΨ
m
loss, as assessed by both time-lapse confocal microscopy and fluorescence-activated cell sorter analysis of cardiomyocytes loaded with an indicator of ΔΨ
m,
tetramethylrhodamine ethylester (TMRE). To further investigate the effects in vivo, we monitored the spatio-temporal changes of ΔΨ
m
in perfused rat hearts subjected to ischemia/reperfusion, using the real-time two-photon confocal imaging system which we recently developed. Briefly, adult rats received direct intramyocardial injections of the siRNA-CypD adenovirus. 3–5 days after injection, the rat hearts were removed and perfused in Langendorff mode. After loading TMRE, the hearts underwent two-photon imaging under excitation with 810 nm line of a Ti:Sapphire laser. Ischemia was achieved by clamping the perfusion line, and reperfusion was achieved by releasing the clamp. The virus contained an expression cassette of green fluorescent protein, allowing us to distinguish transduced cells and non-transduced cells. The progressive loss of ΔΨ
m
induced by myocardial ischemia/ reperfusion was significantly suppressed in siRNA-CypD-transduced cells, compared with non-transduced cells.

Conclusions-

Targeting CypD by RNA interference protects against oxidant-induced cardiomyocyte injury in vitro, and myocardial ischemia/reperfusion in vivo, implicating CypD as a promising molecular target for anti-ischemia/reperfusion therapy.
Abstract 1493: Erythropoietin Stimulates Endothelial Biosynthesis of Tetrahydrobiopterin by Activation of Phosphatidylinositol 3-kinase/Protein Kinase B Signal Transduction Pathway
Authors: d’Uscio Livius V , Santhanam Anantha V , Katusic Zvonimir S
Published: July 2021

Erythropoietin (EPO) has been recognized as a tissue protective cytokine. Recently, it has been shown that vascular protective effects of EPO are dependent on activation of endothelial nitric oxide synthase (eNOS). Tetrahydrobiopterin (BH
4
) is an essential cofactor required for enzymatic activity of eNOS. Therefore, our objective was to characterize the effect of EPO on biosynthesis of BH
4
in vascular wall. Incubation of isolated wild-type (C57BL/6J) mouse aortas for 18 hours at 37°C in minimal essential medium supplemented with recombinant human EPO (1–50 U/ml) caused concentration-dependent increase in intracellular levels of BH
4
as determined by HPLC analysis. Maximum biosynthesis of BH
4
was detected at therapeutic concentrations of 5 U/mL (15.8±1.3 pmol/mg protein; P<0.05 vs control: 8.2±0.4 pmol/mg protein; n=6 – 8). Oxidative products of BH
4
, 7,8-dihydrobiopterin, were unaffected by EPO indicating that EPO does not affect oxidation of BH
4
. Removal of the endothelium abolished EPO-induced biosynthesis of BH
4
(P<0.05; n=5) demonstrating that the vascular endothelium is a major source of BH
4
. Treatment of intact isolated wild-type mouse aortas with a selective phosphatidylinositol (PI)3-kinase inhibitor wortmannin (1 μM) significantly reduced BH
4
biosynthesis by EPO (8.4±0.6 pmol/mg protein; P<0.05; n=6). Stimulatory effect of EPO on production of BH
4
in aorta was also detected in wild-type mice treated with recombinant human EPO (1000 U/kg, s.c. biweekly) for 14 days (P<0.05; n=6). This vascular effect was abolished in protein kinase B (Akt) 1-deficient mice treated with EPO (P<0.05; n=5). Furthermore, aortic GTP cyclohydrolase I (GTPCH I) enzymatic activity was augmented in EPO treated wild-type mice (0.48±0.12 pmol neopterin/mg protein; P<0.05 vs control: 0.23±0.05 pmol neopterin/mg; n=4) but not in EPO treated Akt 1-deficient mice (0.21±0.03 pmol neopterin/mg; n=4), indicating that the selective increase in BH
4
levels was caused by de-novo biosynthesis of BH
4
via Akt/GTPCH I pathway. Our results demonstrate that EPO stimulates biosynthesis of BH
4
in vascular endothelium. This effect is most likely designed to provide optimal intracellular concentration of cofactor necessary for EPO-induced elevation of eNOS activity.
Abstract 1495: Loss of Endothelial NO Synthase Serine 1179 Phosphorylation and Function in ER Stress
Authors: Chen Juan , Qin Honghua , Chiang Pei-Yu , Lu Deqin , Xia Yong
Published: July 2021

Endothelial NO synthase (eNOS) function is critically modulated by protein phosphorylation. In particular, phosphorylation of serine 1179 (S1179, bovine)/1177 (S1177, human and rat) by Akt has emerged as a central mechanism of eNOS regulation under both physiological and pathological conditions. Endoplasmic reticulum (ER) stress is a fundamental unfolded protein response occurred in various diseases. Whether and how ER stress affects eNOS phosphorylation is unknown. To address this issue, we induced ER stress in bovine aortic endothelial cells (BAECs) with Brefeldin A (BFA, 5 μg/ml), a compound blocking protein transport from ER to Golgi apparatus. BFA time-dependently induced ER stress in BAECs as evidenced by the markedly increased expressions of ER chaperon Grp78. Parallel to the time course of ER stress, a progressive loss of eNOS S1179 phosphorylation was seen. ER stress-induced eNOS dephosphorylation was specific to S1179 because the phosphorylation status of eNOS T497 or S635 was unchanged. In cells exposed to BFA for 4 hr, eNOS S1179 phosphorylation was decreased more than 5 fold (17.9±0.1% of control,
P
<0.01, n=5). As a result, eNOS activity was diminished (from 3.32±0.28 to 0.85±0.08 pmol/mg/min,
P
<0.01, n=3). Further studies revealed that ER stress caused Akt T308 and S473 dephosphorylation leading to Akt deactivation. Besides BFA, the loss of eNOS and Akt phosphorylation was also measured in ER stress induced by depleting ER Ca
2+
content with
A23187
(2 μM) or perturbing ER oxidative environment with DTT (5 mM). To determine if these findings from cell culture occur in vivo, we monitored ER stress and eNOS S1177 phosphorylation in postischemic rat hearts. Indeed, severe ER stress and corresponding loss of eNOS S1177 phosphorylation and activity were detected in the infarcted areas of hearts after 1-hr coronary artery (LAD) occlusion followed by 24-hr reperfusion. Collectively, these results demonstrate that ER stress decreases eNOS S1179 phosphorylation and function via Akt deactivation. Ischemia/reperfusion cause ER stress, which, at least in part, accounts for the loss of eNOS S1179 phosphorylation and function in hearts. Thus, reducing ER stress may be an important approach to prevent eNOS dysfunction in postischemic hearts.
Abstract 1498: Agonist-modulated Activation of AMP-activated Protein Kinase: Evidence for a Novel AMPK-Rac1-Akt-eNOS Pathway in Endothelial Cells
Authors: Levine Yehoshua , Michel Thomas
Published: July 2021

The endothelial isoform of nitric oxide synthase (eNOS) is regulated by diverse cell surface receptors. Activation of eNOS by vascular endothelial growth factor (VEGF) and sphingosine 1-phosphate (S1P) involves multiple protein kinases and other signaling proteins, yet the relationships between these pathways are incompletely understood. We designed and validated a series of potent and specific duplex siRNA constructs to knockdown expression of key signaling proteins in bovine aortic endothelial cells, and have identified a novel AMPK-Rac1-Akt hierarchical pathway that is critical for VEGF- and S1P-modulated eNOS activation and angiogenesis. We found that VEGF (10 ng/ml) and S1P (100 nM) promote a rapid ~4-fold increase in AMPK phosphorylation. siRNA constructs targeting AMPKα1 specifically suppress AMPKα1 expression by >90%, and markedly impair agonist-mediated eNOS activation (49 ± 14% decrease in VEGF-induced eNOS activity; 43 ± 19% decrease for S1P;
n
= 4,
p
< 0.05 for both by ANOVA) as well as Akt phosphorylation (38 ± 6% reduction for VEGF; 42 ± 7% reduction for S1P;
n
= 4,
p
< 0.01). In contrast, siRNA-mediated Akt1 knockdown attenuates eNOS activation but does not affect AMPK activation. These results establish that AMPK lies
upstream
of Akt in the pathway leading from receptor to eNOS. siRNA-mediated AMPKα1 knockdown attenuates agonist-mediated activation of the small GTPase Rac1 (51 ± 19% decrease;
n
= 3,
p
< 0.05). Conversely, Rac1 siRNA decreases the phosphorylation of AMPK substrates without affecting phosphorylation of AMPK, implicating Rac1 as an effector of AMPK in eNOS activation. siRNA-mediated knockdown of caveolin-1 significantly enhances AMPK phosphorylation, suggesting that AMPK is negatively regulated by caveolin-1. Finally, we found that cells transfected with AMPK, Rac1, or eNOS siRNA demonstrate severely impaired agonist-modulated endothelial migration and tube formation on Matrigel. These results suggest that VEGF and S1P regulate AMPK as a very key early step in an agonist-modulated AMPK → Rac1 → Akt hierarchy that controls eNOS activation as well as cell migration and endothelial tube formation. These findings may have important implications for the AMPK-dependent control of NO signaling pathways in the vascular wall.
Abstract 1504: Increased Expression of Stem Cell Factor and its Receptor Following LVAD: A Potential Novel Target for Therapeutic Interventions In Heart Failure
Authors: Jahanyar Jama , Youker Keith A , Noon George P , Torre-Amione Guillermo , Koerner Michael M , Loebe Matthias
Published: July 2021

Introduction: Previous studies have demonstrated the involvement of mast cells (MCs) in cardiac remodeling during heart failure. LVADs cause an influx of MCs into the failing heart, but the underlying mechanism is unknown. We hypothesize that stem cell factor (SCF) induces migration of MCs to the heart. This study investigates the potential role of SCF and its receptor (C-Kit) in promoting the recruitment of stem cell derived MCs during heart failure and following LVAD support.

Methods: Myocardial samples were collected from 10 patients undergoing LVAD implantation (Pre-LVAD) paired with samples taken at the time of heart transplantation (Post-LVAD). Biopsies of 4 normal hearts served as controls. We assessed gene expression of SCF and C-Kit. Additionally, we stained for SCF, C-Kit and tryptase protein and utilized In-situ hybridization to determine the origin of SCF.

Results: Real-time PCR: SCF mRNA is significantly increased (P<0.01) following mechanical circulatory support as compared to paired heart failure tissue. C-Kit mRNA was significantly increased post-LVAD, as compared to normal tissues (p<0.05).

Immunohistochemistry: The C-Kit protein was only expressed on cardiac mast cells. In-Situ hybridization: SCF mRNA was found in endothelial cells, myocytes and interstitial cells. This was confirmed by antibody staining for the SCF protein.

Conclusions: LVADs cause an increase of SCF and C-Kit gene expression during unloading. SCF appears to be an important mechanism for the recruitment and maturation of MCs involved in cardiac remodeling, and we suggest that pharmacologic or biologic modification of SCF may provide a new therapeutic path for heart failure treatment.
Abstract 1509: Exercise Training Started Before Myocardial Infarction Improves Survival but Aggravates Left Ventricular Dysfunction
Authors: de Waard Monique C , Duncker Dirk J
Published: July 2021

Introduction:
Regular physical activity in patients with established coronary heart disease not only reduces the incidence of cardiac events, but also reduces the risk of all-cause mortality. Recently, we showed in mice that exercise training (EX) started immediately
after
myocardial infarction (MI) ameliorates left ventricular (LV) dysfunction. Here we tested the hypothesis that additional exercise training
prior
to an acute MI, i.e. a higher level of physical fitness at the time of MI, is associated with improved survival and attenuated LV dysfunction after MI.

Methods and Results:
MI was induced by permanent coronary ligation in 128 C57Bl/6 mice and subsequently followed by 8 weeks of voluntary wheel running (MI-EX) or sedentary housing (MI). In a third group, voluntary wheel running was started two weeks before induction of MI (EX-MI-EX). Sham operated mice served as controls. EX after MI had no effect on survival, infarct size, LV hypertrophy or dilation (Table

). However, EX improved LV function, reflected in enhanced LV fractional shortening (FS), rate of rise in LV pressure at 30 mmHg (LVdP/dt
P30
), and decreased pulmonary congestion and right ventricular weight (RVW). When EX was started prior to MI, post-MI survival nearly doubled and mice ran an average post-MI distance of ~7km/d compared to ~5km/d in MI-EX mice. Infarct cross-sectional area was larger, which was principally due to an increased infarct thickness (0.15±0.02mm EX-MI-EX vs 0.11±0.01mm MI;
P
=0.06). Surprisingly, however, LV hypertrophy and dysfunction were aggravated in the EX-MI-EX group compared to MI-EX.

Conclusion:
In line with our hypothesis, EX started prior to MI improved survival. However, contrary to our hypothesis, the improved survival was associated with a deterioration of LV dysfunction. The latter may have been the result of survival and hence inclusion of mice with the most severe LV dysfunction.
Abstract 1515: Outcomes of Patients With Acute Coronary Syndromes and Prior Coronary Artery Bypass Grafting. Results From the Pravastatin or Atorvastatin Evaluation and Infection Therapy (PROVE-IT-TIMI 22) and the Aggrastat to Zocor (A to Z) trials.
Authors: Brilakis Emmanouil S , de Lemos James A , Cannon Christopher P , Wiviott Stephen D , Murphy Sabina A , Morrow David A , Sabatine Marc S , Banerjee Subhash , Blazing Michael A , Califf Robert M , Braunwald Eugene
Published: July 2021

Background:
Patients with prior coronary artery bypass graft surgery (CABG) who develop acute coronary syndromes (ACS) are at high risk for major adverse cardiac events. The benefits of intensive statin therapy, targeting an LDL cholesterol of < 70 mg/dL, in patients with ACS and prior CABG have not been well studied.

Methods:
The effect of intensive vs. moderate statin therapy was assessed in patients with and without prior CABG participating in the Pravastatin or Atorvastatin Evaluation and Infection Therapy (PROVE-IT TIMI 22) or the Aggrastat to Zocor (A to Z) trials.

Results:
Six hundred and forty of the 8655 patients (7.4%) enrolled in PROVE IT-TIMI 22 or A to Z had undergone CABG prior to enrollment. Prior CABG patients were older, more likely to be men and had a higher TIMI risk score. After a median follow-up of 2 years, compared to patients without prior CABG, those with prior CABG had higher risk of cardiovascular death (6.2 vs. 2.8%), myocardial infarction (14.2% vs. 6.6%), and readmission for ACS (7.9% vs. 4.4%) (p<0.001 for all comparisons), but a lower rate of repeat coronary revascularization (22.7% vs. 26.9%, p=0.01). Compared to moderate statin therapy, intensive statin therapy decreased the combined endpoint of cardiovascular death, myocardial infarction, stoke, and readmission for an acute coronary syndrome (A to Z primary endpoint) to a similar extent in patients with and without prior CABG (Table

). The benefit of intensive statin therapy in prior CABG patients appeared to be due to a reduction in unstable angina requiring hospitalization, with no significant difference in the incidence of death, myocardial infarction, or coronary revascularization.

Conclusions:
Compared to ACS patients without prior CABG, those with prior CABG have significantly higher risk for death and adverse cardiac events and appear to show similar benefit from intensive statin therapy.

Effect of intensive statin therapy on outcomes of patients with and without prior CABG
Abstract 1539: National Study of Awareness of Cardiovascular Disease Risk among Middle-Aged Women in Korea
Authors: Chu Sang Hui , Choi Eun Jin , Kim Sue , Yoo Ji-Soo , Kim Hee Soon , Oh Eui-Geum , Jang Yangsoo
Published: July 2021

Background:
Cardiovascular disease (CVD) risk factors (e.g., obesity, hypercholesterolemia, and metabolic syndrome) and morbidity are more prevalent in middle-aged women than in men of the same age in Korea. CVD related deaths rate number one among Korean women and have surpassed morbidity in men since 1992. This study, the first national Korean survey to focus on CVD in middle-aged women, aimed to assess current awareness and knowledge of CVD risk factors, as well as risk reduction activities among Korean middle-aged women.

Methods and Results:
A face-to-face survey of a nationally representative random sample of Korean women aged 40 – 64 years was conducted in July-August, 2006. Of the 1004 respondents surveyed, 47.9% were pre-menopausal, 8.6% peri-menopausal, and 43.5% post menopausal. CVD risk awareness, knowledge, and preventive actions to decrease risk were evaluated by use of a standard questionnaire, which included a modified version of the AHA National Study on Women’s Awareness of Heart Disease Questionnaire (1997, 2000, 2003). Awareness and knowledge of CVD among respondents were very low in terms of considering CVD as the most worrisome health problem after menopause (5.2%), perceiving CVD as the leading cause of death in women (19.8%), identifying HDL cholesterol as beneficial (8.5%), and LDL as harmful (6.7%). While many respondents reported checking blood pressure in the past year (88.2%), more than half did not receive blood glucose (50.3%) or total cholesterol testing (67.8%). Few respondents could correctly identify health ranges for fasting blood sugar (10.8%) or total cholesterol (4.5%). Respondents reported various lifestyle measures to prevent CVD, and while education and economic status were positively associated with taking preventive actions, body mass index was negatively associated.

Conclusion:
Nurses have been involved in general health promotion in Korea but this study underscores the need to specifically target middle-aged women to promote general awareness and knowledge of CVD risk, particularly interventions that focus on women who are overweight and of low socio-economic status.

This work was supported by the 2006 Health Promotion Research Fund from the Ministry of Health and Welfare.
Abstract 1545: Insulating an Open Irrigated Ablation Electrode Improves Electrode Temperature Feedback for Radiofrequency Lesion Control
Authors: Yokoyama Katsuaki , Nakagawa Hiroshi , Wittkampf Fred H , Ikeda Atsushi , Dando Jeremy D , Wang Huisun , Puryear Harry A , Pitha Jan V , Lazzara Ralph , Jackman Warren M
Published: July 2021

Open irrigation (Irrig) cools the electrode and electrode-tissue interface (ETI), preventing thrombus. Improving electrode temperature (ET) feedback by insulating the Irrig electrode internally may help prevent excessive tissue heating. The purpose was to compare an insulated Irrig electrode to a conventional Irrig electrode in ET response and lesion formation using a canine thigh muscle preparation.

Methods
In 11 dogs, the skin over the thigh muscle was incised and raised to form a cradle which was superfused with heparinized blood at 37°C. The 7F insulated catheter has 6 Irrig holes proximal to a 2.5mm tip electrode (spray around electrode and ETI) and one thermally insulated Irrig channel through the electrode (only external cooling, Ext Cool, St Jude Medical). The Ext Cool and a conventional 7F, 2.5mm open Irrig catheter (external and internal electrode cooling, Ext/Int Cool, St Jude Medical) were held perpendicular or parallel to thigh muscle. RF was applied for 60 sec (n=176) at 10, 15, 20, or 25W with saline Irrig at 17ml/min in low blood flow (<0.1 m/sec) to favor thrombus. ET, ETI and tissue temperatures (3 and 7mm depths) were measured. After each RF, blood was removed to examine for thrombus.

Results
Table

and Fig

Conclusions
Ext Cool had:

greater correlation between ET and both lesion depth (r=0.84 vs 0.54) and steam pop (ET≥51°C vs ET 32– 48°C);

lower ETI temperature and less thrombus.
Abstract 1548: High Plasma Levels of Stromal Cell-Derived Factir-1 alpha Predict Future Cardiovascular Events in Patients with Previous Myocardial Infarction
Authors: Kodama Yasushi , Sano Keita , Hirano Mitsumasa , Nakamura Takamitsu , Mende Akira , Kitta Yoshinobu , Obata Jun-ei , Takano Hajime , Yano Toshiaki , Kobayashi Tsuyoshi , Fujioka Daisuke , Saito Yukio , Kawabata Ken-ichi , Kugiyama Kiyotaka
Published: July 2021

Stromal cell-derived factor-1 alpha (SDF-1α) is expressed in ischemic myocardium and atheromatous plaques and plays a key role in the repair of injured myocardium. We examined whether SDF-1α in circulating plasma may play a role in pathophysiology of myocardial infarction (MI).

Methods and Results:
SDF-1α levels in plasma from a peripheral vein (PV) were measured using ELISA in 206 consecutive patients with previous MI and in 50 age- and sex-matched controls. The levels were also measured in plasma from the aorta (AO) and the anterior interventricular vein (AIV) in a subgroup of 82 patients with anterior MI. After baseline measurements, all patients with previous MI were prospectively followed for ≤ 60 months or until occurrence of a clinical cardiovascular event: cardiac death, nonfatal myocardial infarction, refractory angina pectoris requiring coronary revascularization, or hospitalization with congestive heart failure. PV levels of SDF-1α were higher in patients with MI than controls (2750 ± 79 vs. 2351 ± 72 pg/mL, p < 0.01). In addition, PV levels were significantly higher in MI patients with (n = 42) than without an event (n = 164) (2909 ± 108 vs. 2645 ± 41 pg/mL, p < 0.01). In multivariate Cox hazard analysis, a higher level of SDF-1α (> 3040 pg/mL, defined by ROC analysis) was a predictor of the events independently of traditional coronary risk factors (hazard ratio 2.2, 95% CI 1.1 – 4.1, p < 0.01). Moreover, there was a significant step-up in SDF-1α levels in the AIV compared with the AO in patients with anterior MI (2868 ± 49 vs. 2681 ± 60 pg/mL, p < 0.05). The AIV - AO difference in SDF-1α levels, reflecting release from ischemic myocardium, correlated positively with PV levels of SDF-1α (r = 0.23, p < 0.05). Both the AIV - AO difference in SDF-1α levels and the PV levels had a significant correlation positively with PV levels of brain natriuretic peptide and inversely with left ventricular (LV) ejection fraction.

Conclusions:
Higher SDF-1α levels in the peripheral circulation independently predict cardiovascular events in patients with prior MI. SDF-1α is released from ischemic myocardium in proportion to the severity of LV dysfunction via a compensatory mechanism, which may partly contribute to increased circulating levels of SDF-1α in MI survivors.
Abstract 1550: Non-Doppler Two-Dimensional Strain Imaging for Early Detection of Heart Transplant Recipients with Coronary Stenoses
Authors: Dandel Michael , Lehmkuhl Hans , Knosalla Christoph , Hetzer Roland
Published: July 2021

Background:
Non-Doppler based two-dimensional (2D) strain imaging can reveal wall motion alterations not visible by conventional echocardiography (ECHO) and like tissue Doppler imaging (TDI) it can detect myocardial deformation (regional shortening and thickening) in the absence of visible ventricular wall displacement. Because TDI is dependent on the direction of Doppler angle of incidence in relation to myocardial motion, in our attempt to assess of the diagnostic value of strain and strain rate changes for early detection of transplant coronary arteriopathy (TCA), we focused our attention on the angle independent 2D strain imaging.

Methods:
In 68 heart recipients with normal LV wall motion and ejection fraction in conventional ECHO, 2D strain LV wall motion analysis were additionally performed before each follow-up cardiac catheterization. Circumferential, radial and longitudinal strain and strain rate were calculated from parasternal short axes and apical (3- and 4-chamber) views, respectively. 2D strain parameters were tested for relationships with angiographic findings.

Results:
In comparison with patients without TCA, those with angiographic TCA showed lower global systolic strain rate (radial, circumferential and longitudinal) values and longer systolic times measured from onset of contraction to the peak of systolic strain (p<0.01). For radial peak systolic global strain rate values below 1.1/s we found a 93.3% likelihood of angiographic TCA in general, regardless of the presence or absence of focal stenoses on main coronaries. Regional strain and strain rate analyses showed differences in contraction asynchrony and dyssynergy indexes between patients with and without focal stenoses (p<0.01). For longitudinal midsystolic dyssynchrony index values >0.5 we found an 88.2% likelihood of relevant focal coronary stenoses (>50% narrowing).

Conclusions:
In heart allografts with apparently normal LV kinetics in conventional ECHO, simple global strain rate measurements allow early TCA prediction, but without the ability to differentiate between diffuse TCA and predominantly focal coronary stenoses. Such differentiation is possible with more complex regional strain analyses using contraction asynchrony and dyssynergy indexes.
Abstract 1552: Cardioplegic Arrest And Subsequent Reperfusion Induce Urocortin Expression In Non-apoptotic Cardiac Cells Selectively Associated With Mitochondrial Relocation Of PKCϵ
Authors: Chen-Scarabelli Carol , Yuan Zhaokan , Faggian Giuseppe , Santini Francesco , Rungatscher Alessio , Tessari Maddalena , Ragusa Renato , Martindale Joshua , DiRezze Justin , Patel David , Raddino Riccardo , Mazzucco Alessandro , Saravolatz Louis , Scarabelli Tiziano M
Published: July 2021

BACKGROUND:
Cardioplegic arrest and subsequent reperfusion inevitably expose the heart to an iatrogenic ischemia/reperfusion injury (iIRI). We previously reported that iIRI caused mitochondria-initiated myocyte apoptosis, but also induction of urocortin (Ucn), an endogenous cardioprotective peptide. We also showed that Ucn induced PKCϵ-mediated opening of mitochondrial K
ATP
channels in isolated heart mitochondria.

AIM:
To investigate, in patients exposed to iIRI, the cardioprotective role and the mechanism of action of Ucn, with respect to PKCϵ expression, activation and relocation.

METHODS AND RESULTS:
Two sequential biopsies were obtained from the right atrium of 25 patients undergoing coronary artery bypass grafting at the start of grafting (internal control) and 10 mins after release of the aortic clamp. Mean values of ejection fraction, aortic cross-clamping time and number of grafts were 51±8; 48±8 mins; and 3.6±0.5 respectively. In hearts exposed to iIRI, RT-PCR and immunostaining showed Ucn induction at the mRNA (255% of basic levels, p<0.05) and protein level (28±2.1% positive myocytes vs 3.1±0.6% of internal control; p<0.01) respectively. iIRI also induced a selective increase of PKC-ϵ mRNA (225% of internal control; p<0.05) and a two-fold overexpression of total PKCϵ isoform (assessed by Western blotting; p<0.05), which paralleled a 2.9 fold increase in PKCϵ phosphorylation (p<0.01). TUNEL positivity (<0.1% and 2.9±0.7% positive myocytes pre- and post-iIRI respectively; p<0.01) was only seen in Ucn-negative cells, and, of note, Ucn-positive myocytes showed concurrent mitochondrial relocation of phosphorylated PKCϵ, as documented by mitochondrial-activated PKCϵ colocalization, calculated by confocal microscopy with an image analyzer software (% overlap: 57±5 vs 11±2 in Ucn-negative cells; p<0.01). Western blotting carried out in pools of cytosolic and mitochondrial fractions confirmed a 2.5 fold increase in mitochondrial localization of phosphorylated PKC-ϵ following iIRI (p<0.05).

CONCLUSIONS
: In patients exposed to iIRI, Ucn expression in viable cells was selectively associated with phosphorylation and mitochondrial relocation of PKCϵ, suggesting a cardioprotective role for endogenous Ucn in the human heart.
Abstract 1554: PX-18 - A Novel Inhibitor of Type IIA Secretory Phospholipase A
2
Induces Pre and Post-Conditioning against Myocardial Infarction in Rabbit: Role of Mitochondrial K
ATP
Channels.
Authors: Ockaili Ramzi A , Salloum Fadi , Mehta Christopher K , Franson Richard C , Kukreja Rakesh C
Published: July 2021

Background:

The low-molecular-weight, calcium-dependent type IIA secretory phospholipase A
2
(sPLA
2
) has been implicated in irreversible cell damage following ischemia-reperfusion (I/R) injury. We examined the protective effect of PX-18, a novel sPLA
2
inhibitor, during I/R in the heart. Since mitochondrial K
ATP
(mitoK
ATP
) channel opening is an essential component of ischemic tolerance induced by preconditioning in hearts, we also interrogated the role of these channels in PX-18-induced protection.

Methods and Results:

Rabbits were treated with PX-18 (60 mg/kg ip) 30 min prior to 30 min of regional ischemia and 3 hrs of reperfusion. MitoK
ATP
channel blocker 5-hydroxydecanoate (5-HD, 5 mg/kg iv) was given 10 min before I/R. Infarct size (IS) was measured by computer morphometry of tetrazolium stained sections. IS (mean ± SE) was reduced in rabbits treated with PX-18 as compared to vehicle or non-treated controls (43% reduction)[Fig.1

]. 5-HD blocked the protection of PX-18 as shown by an increase in IS. 5-HD alone had no effect on IS. Risk areas were not different among groups (not shown). Furthermore, PX-18 administration as an iv bolus (30 mg/kg) further reduced IS, both when given post-ischemia (55% reduction), and, importantly, when given 1 hr after reperfusion (61% reduction) [Fig. 1

]. PX-18 had no significant effect on hemodynamics.

Conclusion:

These data suggest that PX-18 induces pharmacological preconditioning in the heart which is mediated by opening of mitoK
ATP
channels. Also, the drug was cardioprotective when administered after ischemia or 1 hr after reperfusion. We conclude that inhibition of sPLA2 is a powerful strategy to induce protection against I/R injury.
Abstract 1562: Long-term Results (up To 19 Years) Of Balloon Angioplasty Of Coarctation Of The Aorta On Systemic Hypertension And Left Ventricular Hypertrophy.
Authors: Hassan Walid , Fawzy Mohamed , Buraiki Jehad Al , Al Amri Mohamed , Shoukri Mohamed , Canver Charles
Published: July 2021

Aim
: To define the long-term effect of balloon angioplasty (BA) of aortic coarctation (AC) on systemic hypertension and left ventricular hypertrophy (LVH) in adolescent and adult patients.

Methods
: Follow-up data of 53 patients (mean age 24 ± 9 years) undergoing BA for discrete AC at median interval of 12.5 years (range 5–19 years) including cardiac catheterization, MRI and Echocardiography form the basis of this study. Patients were divided into two groups (A&B) based on whether or not long-term antihypertensive therapy was required.

Results
: No early or late deaths occurred. Fifty-one patients had baseline hypertension, 49 patients had baseline LVH (92%), BA produced an immediate reduction in peak AC gradient from 66 ± 23 mmHg (95% confidence interval [CI]: 59.5 to 72.7) to 10.8 ± 7 mmHg (95% CI: 8.8 to 12.5) (p< 0.0001). Follow-up catheterization 12 months later revealed a residual gradient of 6.2 ± 6 mmHg (95% CI: 4.4 to 7.9) (p<0.001). The Doppler gradient across coarctation decreased from 59.6 ± 17 to 16 ± 8.4 mmHg at one year and 12.0 ± 6.9 mmHg at last follow-up. Left ventricular mass index (LVMI) decreased significantly in 48 patients (98%) from 132 ± 30.7 (95% CI: 122 to 141.9) to 86 ± 19.9 gram/m
2
(95% CI: 79.5 to 92.5)(p<0.0001). The systolic blood pressure decreased from 165 ± 17 mmHg (95% CI: 159 to 171) to 125 ± 10 mmHg (95% CI: 122 to 131, p<0.001) in 40 patients (group A) and from 184 ± 19 mmHg (95% CI: 169 to 198) to 142 ± 22 mmHg (95% CI: 124 to 156, p<0.001) in 11 patients (group B). The blood pressure had normalized without medication in 40 (78%) of the 51 patients (165 ± 17 mmHg to 115 ± 10 mmHg).

Conclusion
:

Long-term results of BA for discrete AC are excellent and should be considered as first option for treatment of this disease;

Regression of LVH (≥ 20% reduction in LVMI) occurred in 98% of patients after BA and only 22% of patients required medications for hypertension.
Abstract 1565: Characterization and Outcome of Patients with Severe Symptomatic Aortic Stenosis Referred for Percutaneous Aortic Valve Replacement
Authors: Kapadia Samir R , Svensson Lars , Goel Sachin , Wallace Lee , Rodriguez Leonardo , Stewart William , Tuzcu E M
Published: July 2021

Introduction:
Although severe symptomatic aortic stenosis (AS) is associated with poor long-term outcome without aortic valve replacement (AVR), many patients are considered high risk for AVR surgery. These patients are typically not referred to cardiac surgery and therefore remain ill defined. Many of these patients are now referred for possible percutaneous AVR (percAVR). We report the clinical and echocardiographic characteristics of these patients with their outcome.

Methods:
All patients screened for percAVR between 2/06 to 3/07 were studied. Clinical and echocardiographic characteristics of patients undergoing surgical AVR (sAVR), percAVR, balloon aortic valvuloplasty (BAV) and medical management were compared. Clinical follow-up was performed for all cause mortality. Patients that were bridged to sAVR or percAVR after BAV were included in the respective groups.

Results:
We screened 92 pts for consideration of percAVR at our institution in 1 year. Of these, 19 pts underwent surgical AVR, 18 patients percAVR and 36 patients had medical management without BAV. BAV was performed in 30 patients of which 8 pts underwent percAVR and 3 had sAVR. Most common reasons for medical management included death while being screened (n=10, 28%), patient not interested in the study (n=10, 28%) and questionable severity of symptoms or AS (n=9, 25%). BAV was used in patients that could not wait for percAVR to become available with an intention to bridge. This could not be accomplished in 9 (45%) pts due to death while waiting for percAVR, 4 (20%) pts doing well after BAV not wanting percAVR, and the remaining 6 (30%) pts with exclusion from the current percAVR protocol (e.g. age, bleeding, infection, etc).

Conclusion:
Symptomatic patients with severe AS have high mortality if AVR is not feasible in a timely manner. About one fifth of the patients referred for percAVR could undergo sAVR with good outcome. Patients managed medically or with BAV alone have unfavorable outcomes.

Characteristics and Outcome of Screened Patients
Abstract 267: A Single Dose of Reconstituted High Density Lipoprotein Reduces Expression of Tissue-Factor In Human Carotid Atherosclerotic Plaques
Authors: Nasr Hosaam H , Loftus Ian M , Sayed Saiqa , Jones Alun , Torsney Evelyn , Thompson Matthew M , Cockerill Gillian W
Published: July 2021

Background:
Multiple infusions of HDLs have been shown to mediate approximately 4% reduction in plaque volume. This may relate to removal of intra-plaque lipid, but the precise mechanism is unknown. To test the hypothesis that HDLs may influence plaque stabilisation through modulating transcription, we examined the effects of a single dose of rHDL on expression of thrombomodulatory genes in carotid plaques.

Materials and Methods:
Forty patients undergoing carotid endarterectomy (CEA) were stratified to three groups: early symptomatics (
n
=12, stroke/transient ischemic attack (TIA) 1month before CEA)late symptomatics (
n
=14, stroke/TIA > 1month before CEA); and asymptomatics (
n
=12). RNA was isolated from plaques following CEA, and expression of the thrombomodulatory genes, tissue factor (TF); tissue factor pathway inhibitor (TFPI); thrombomodulin (TM); tissue type plasminogen activator (tPA); urokinase plasminogen activator (uPA); plasminogen activator inhibitor-1 (PAI-1), measured using QRT-RT-PCR. Nine patients with early symptomatic carotid disease, undergoing CEA, were then randomised to infusion of reconstituted HDL (rHDL) 80mg/kg Apo A-I (
n
=4) or a similar volume of phosphate buffered saline (
n
=5). Plaque specimens were collected 24 hrs later and RNA isolated for QRT-RT- PCR measurement of thrombomodulatory gene expression.

Results:
A significant difference in TF, TM, tPA and PAI-1 genes were observed in the 3 patient groups (see Table 1

). In the rHDL group, a single dose of rHDL reduced the expression of TF (0.71 (0.65–0.75) vs 0.98 (0.81–1.14), P=0.05). No significant difference was observed in other thrombomodulatory factors between the 2 groups.

Conclusions:
Plaque stabilisation, which occurs within one month of a clinical event may be facilitated, at the transcriptional level, following rHDL infusion. We hope to report a larger double blind placebo controlled trial which will determine the full effects of rHDLs on plaque stability.

Table 1
Abstract 1595: Positive Inotropic Effect Of Relaxin-2 In Atrial Myocardium Of Terminally Failing Hearts: Role Of Protein Kinase A And Potassium Channels
Authors: Dschietzig Thomas , Kinkel Till , Alexiou Konstantin , Baumann Gert , Stangl Karl
Published: July 2021

The insulin-like peptide relaxin, a pregnancy hormone, exerts anti-fibrotic, renal, central nervous, and vascular effects, and is a positive inotropic agent in rat atrial myocardium. We have recently demonstrated that relaxin acts as compensatory mediator in human heart failure. This is the first investigation of the inotropic effects of relaxin-2 in human myocardium. We used human right and left atrial as well as right and left ventricular myocardial samples obtained from donor hearts that were not transplanted for technical reasons (n=5) and from explanted, terminally failing hearts (n=8; 4 patients with dilated cardiomyopathy, 4 patients with ischemic cardiomyopathy). In right and left atrial preparations from both donor and failing hearts, human relaxin-2 evoked positive inotropic effects (EC50 of peak developed tension for isometric twitches; donor, 0.5 ± 0.1 nM [right atrium] and 0.6 ± 0.1 nM [left atrium]; failing, 0.6 ± 0.1 nM [right atrium] and 0.6 ± 0.1 nM [left atrium]; maximum peak developed tension in percent of baseline; donor, 283 ± 35 % [right atrium] and 267 ± 30 % [left atrium]; failing, 258 ± 38 % [right atrium] and 268 ± 34 % [left atrium]). These effects could be prevented by treatment with the protein kinase A inhibitor 5–24 amide and with glibenclamide, a blocker of ATP-sensitive potassium channels. Staurosporine, a protein kinase C inhibitor, and KT-5823, a protein kinase G inhibitor, had no effects. On the other hand, a positive inotropic effect of relaxin-2 could be found neither in donor nor in failing right and left
ventricular
myocardium although all preparations showed similar inotropic responses to increased extracellular calcium concentrations. In conclusion, our findings indicate that the positive inotropic atrial effect of human relaxin-2 is well preserved in terminally failing human myocardium. The effect is mediated via protein kinase A and ATP-sensitive potassium channels. In ventricular myocardium, there is no such inotropic action of relaxin.
Abstract 1601: Comprehensive Evaluation of the Left Ventricular Systolic and Diastolic Synchronicity in 160 “Completely” Healthy Normal Volunteers Using Tissue Doppler Echocardiography
Authors: Kim Hyung-Kwan , Park Keun-Ho , Chang Suna-A , Park Jin-Shik , Kang Hyun-Jae , Koo Bon-Kwon , Kim Yong-Jin , Kim Sang-Hyun , Chae In-Ho , Oh Byung-Hee , Park Young-Bae , Sohn Dae-Won
Published: July 2021

Background
Growing use of the left ventricular(LV) systolic(LVSIsys) and diastolic synchronicity indexes(LVSIdia) in selecting potential responders to cardiac resynchronization therapy(CRT) has created a need for normative reference values. This study was performed to determine reference ranges for tissue Doppler imaging-derived LVSIsys and LVSIdia, and to assess their relationships to age and conventional parameters reflecting LV systolic and diastolic functions.

Methods and Results
We recruited 160 completely healthy volunteers (45±13yrs, 104 men) free of any systemic or cardiovascular disease. Maximal difference and SD of time to peak systolic and early diastolic velocities for LVSIsys and LVSIdia were measured using 6- and 12-segment models. Table and Figure

represent normal ranges. Aging was not found to significantly change LVSIsys, whereas LVSIdia progressively and consistently increased with age. Significant correlations were observed between LVSIdia and parameters representing LV diastolic function, i.e. early mitral inflow velocity and its deceleration time, and early mitral annulus velocity. A physiologic rise in LV mass/Ht
2.7
showed a weak, but significant correlation with LVSIdia(
r
= 0.15 to 0.22), but not with LVSIsys. On multivariate analysis, age-dependent increase in LVSIdia was confirmed.

Conclusions
Age-specific reference ranges for LVSIsys and LVSIdia are presented here. LVSIsys remain stable throughout age groups, whereas LVSIdia progressively increases with age. These data given here will be useful for defining abnormal LV synchronous contraction and relaxation, and help better select patients likely to respond favorably to CRT.
Abstract 1624: Myocardial Fibrosis is associated with Reduced Longitudinal Strain Pattern in Hypertrophic Cardiomyopathy Despite Preserved Left Ventricular Ejection Fraction: A Multi-modality Imaging Study
Authors: Mishra Micky , Popovic Zoran B , Kwon Deborah H , Halley Carmel , Thamilarasan Maran , Schoenhagen Paul , Flamm Scott D , Lever Harry M , Desai Milind Y
Published: July 2021

Background:
There is a high prevalence of myocardial fibrosis in hypertrophic cardiomyopathy (HCM) patients, despite preserved left ventricular ejection fraction (LVEF). Association of myocardial fibrosis and longitudinal strain (LS) in such patients is not well understood.

Methods:
We studied 46 consecutive HCM patients (mean age 43±14 years, 30 men) who had transthoracic echocardiography (TTE, GE Medical, USA) and delayed hyper-enhancement magnetic resonance imaging (DHE-MRI, Siemens 1.5 T scanner, Germany), 20 minutes after injection of 0.2 mmol/kg of Gadolinium. Speckle tracking TTE was used to assess LS in LV (segmental and global) (EchoPac, GE Medical, USA). Fibrosis was determined semi-automatically on DHE-MR images, in a 12-segment short-axis model (apex, mid and base) of LV using custom software (Siemens Research) & defined as intensity >2 standard deviation above viable myocardium.

Results:
Global end-systolic LS correlated with number of fibrotic segments (r = 0.50, p = 0.0004; Figure

) and total myocardial fibrosis % (r = 0.43, p = 0.001). Association of fibrosis and regional LS is shown in Table

. In a multivariate analysis, predictors of lower segmental LS were presence of fibrosis and basal segment location (both p < 0.001).

Conclusion:
Myocardial fibrosis is associated with depressed global and regional LS in HCM patients, despite preserved global LVEF.

Table
Abstract 1634: Validation of 64-Slice Multi-Detector Computed Tomography Coronary Angiography Against Invasive Hemodynamic Measurements of Fractional Flow Reserve in the Detection of Non-Flow-Limiting Coronary Stenoses
Authors: Akram Kamran , O’Donnell Robert , LaCorte Jennifer , Brown Charles , Voros Szilard
Published: July 2021

Introduction.
Multi-detector CT coronary angiography (CorCTA) has been introduced for coronary artery disease (CAD) detection and been validated against invasive angiography (XRA) and intravascular ultrasound (IVUS). However, the diagnostic accuracy of CorCTA-derived area stenosis (%AS), diameter stenosis (%DS), minimal lumen area (MLA) and minimal lumen diameter (MLD) have not been previously validated against fractional flow reserve (FFR).

Methods.
Twenty consecutive patients enrolled in a study of non-obstructive CAD underwent CorCTA and invasive FFR measurements within 2 weeks. Patients without prior CAD with visual intermediate stenoses (40–70%) by either XRA or CorCTA were eligible. CorCTA was performed on a 64-slice scanner. %AS, %DS, MLA and MLD were measured quantitatively with commercial software (SurePlaque; Vital Images). FFR was determined by averaging 3 independent measurements after intracoronary injection of adenosine. Statistical analysis was done using Analyse-It software.

Results.
CorCTA-derived values (mean±SD) in the group were as follows: %AS=43.8±21.3%, %DS=58.9±21.4%, MLA=3.9±3.0mm
2
, MLD=1.4±0.8mm, FFR=0.89±0.09. Two patients had flow-limiting stenoses by FFR. Table

shows the area under the curve (AUC), optimal cutpoint, sensitivity, specificity, PPV and NPV for the parameters to predict non-flow-limiting FFR. All parameters performed well in predicting non-flow-limiting FFR as expressed by the AUC; these were highly significant. Values below stenosis cutpoints (%AS<60%, %DS<77%) and MLA>3.0 mm
2
, MLD>0.89 mm reliably excluded flow-limiting stenoses. Cutpoints were higher for %DS vs %AS (77% vs. 60%).

Conclusions.
To our knowledge, this is the first study to compare CorCTA to FFR. %AS, %DS, MLA and MLD performed very well in excluding hemodynamically significant stenoses. While%DS and MLD by CorCTA tend to overestimate the significance of stenosis, %AS and MLA correlate well to similar values derived from IVUS.

Accuracy of CorCTA in Excluding Flow Limiting Stenoses As Measured by FFR