bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 8897: Transplantation of Human Embryonic Stem Cell-Derived Cardiomyocytes Decreased the Incidence of Arrhythmias in a Guinea Pig Acute Infarct Model
Authors: Shiba Yuji , Kim Jonathan , Fernandes Sarah , Dupras Sarah , Van Biber Benjamin , Izawa Atsushi , Mignone John , Dardas Todd , Hanna Ramy , Murry Charles E , Gold Joseph D , Viswanathan Mohan , Laflamme Michael A
Published: April 2024

Introduction:
The transplantation of human embryonic stem cell-derived cardiomyocytes (hESC-CMs) has been shown to improve ventricular function in rodent infarct models. However, a number of important safety issues remain unresolved, including concerns about the risk of pro-arrhythmic effects. To address this, we conducted a transplantation study using primary electrocardiographic endpoints and the guinea pig model, as this species has a heart rate better matched to humans than do rats and mice.

Methods and Results:
Ten days after undergoing near-transmural cryoinjury of the anterior left ventricle, immunosuppressed adult guinea pigs received direct intra-cardiac injections of 100x10
6
hESC-CMs (n=15 animals), 100x10
6
hESC-derived non-cardiac cells (non-CM, n=13), or vehicle alone (n=14). By histology at 28 days post-transplantation, the recipients of hESC-CMs showed engrafted human myocardium that occupied 8.4±1.5% of the scarred injury area, and no teratomas were identified. By echocardiography at 28 days post-transplantation, hESC-CM recipients had a significantly higher fractional shortening than did controls (hESC-CM: 25.4±0.8%, non-CM: 20.3±1.2%, vehicle: 21.0±1.3%, p<0.01). During telemetric ECG monitoring from days 3 through 28 days post-transplantation, a smaller fraction of hESC-CM recipients exhibited spontaneous ventricular tachycardia (VT) than in controls (20% of hESC-CM, 54% of non-CM, 28% of vehicle recipients). Moreover, when these animals were challenged with programmed electrical stimulation at 28 days post-transplantation, hESC-CM recipients showed a substantially reduced incidence of induced VT (6.7% of hESC-CM, 61.5% of non-CM, and 50.0% of vehicle recipients, p<0.05).

Conclusion:
hESC-CM grafts survived in injured guinea pig hearts, and their transplantation resulted in preserved mechanical function, as well as a reduced incidence of both spontaneous and induced arrhythmias. The mechanistic basis of this arrhythmia-suppressive effect remains unknown, but it may provide a new rationale for the preclinical development of cardiac cell therapies based on hESC-CMs.
Abstract 8900: Urinary β
2
-Microglobulin-Creatinine ratio is Associated with High Risk in Chronic Heart Failure Patients
Authors: Otaki Yoichiro , Takahashi Hiroki , Watanabe Tetsu , Shishido Tetsuro , Funayama Akira , Kadowaki Shinpei , Narumi Taro , Netsu Shunsuke , Honda Shintaro , Hasegawa Hiromasa , Ishino Mitusnori , Nishiyama Satoshi , Arimoto Takanori , Miyashita Takehiko , Miyamoto Takuya , Kubota Isao
Published: April 2024

Background
It has been reported that renal dysfunction has strong association with clinical outcomes in chronic heart failure (CHF) patients. Recent study demonstrated that several urinary markers were related to cardiac prognosis in CHF patients. Urinary μ
2
-microglobulin-creatinine ratio (UBCR) is a marker for renal tubular damage (RTD) and related to rapid deterioration of renal function. However, association between UBCR and cardiac prognosis has been not studied. The purpose of the present study was to examine whether: (1) UBCR is correlated with severity of heart failure; and (2) UBCR can predict clinical outcomes in CHF patients.

Methods and Results
We measured UBCR, urinary microalbumin-creatinine ratio, N-acetyl-beta-D-glucosamidase and estimated glomerular filtration rate (eGFR) in 193 CHF patients. Patients were prospectively followed during a median follow up period of 353 days. There were 46 cardiac events, including 10 cardiac deaths and 36 re-hospitalizations for worsening heart failure. Levels of UBCR increased with advancing NYHA functional class. Patients with cardiac events had higher levels of UBCR than those without. In the univariate Cox proportional hazard analysis, age, NYHA functional class, brain natriuretic peptide, eGFR and UBCR were independent risk factor for cardiac events. A multivariate Cox proportional hazard analysis revealed that UBCR is an independent predictor of cardiac events in CHF patients. We defined RTD as UBCR > 300 μg/g according to our previous report. Kaplan-Meier analysis demonstrated that cardiac event rate was higher in patients with RTD than in those without. In addition, Kaplan-Meier analysis demonstrated that RTD could strictly classify the prognosis of CHF patients without chronic kidney disease.

Conclusion
UBCR was related to the severity of heart failure and associated with high risk in CHF patients. RTD, as implicated by UBCR, could add clinical information about cardiac prognosis in CHF patients.
Abstract 8914: Late Gadolinium Enhancement Predicts Poor Prognosis in Patients with Known or Suspected Heart Failure
Authors: Mahmod Masliza , Mahmoud-Tawfik Khaled , Alpendurada Francisco , Roussin Isabelle , Chan Cheuk F , Pennell Dudley J , Prasad Sanjay K
Published: April 2024

Background:
Myocardial scar as detected by cardiac magnetic resonance (CMR) has been documented to provide important diagnostic information in patients with heart failure (HF). What is less clear is its' prognostic value in this cohort of patients.

Methods:
A total of 153 consecutive patients with known or suspected HF referred for CMR imaging from 2005 to 2008 were prospectively followed for clinical events. The primary composite end point (EP) was all-cause mortality or unplanned cardiovascular hospitalization. Secondary composite EP included unplanned HF hospitalization, worsening of NYHA class or cardiac resynchronization therapy implantation. Patients were divided into two groups: late gadolinium enhancement (LGE) + and LGE- depending on the presence and absence of LGE respectively. Post-scan follow-up was assessed by review of case notes, clinic visits and review of the National Survival database.

Results:
LGE was present in 94 patients (61%). Of these, 53% had infarct, 26% had mid-wall and 8% had patchy distribution of LGE. The LGE+ patients were older, more likely to be male, with larger left ventricular (LV) volumes, increased LV mass and a lower LV ejection fraction. At a mean follow-up of 3.1 ± 1.4 years, 39 (41%) in the LGE+ and 10 (17%) in the LGE- groups experienced the primary EP. Forty-six (49%) in the LGE+ and 12 (20%) in the LGE- groups experienced the secondary EP. Kaplan-Meier analysis revealed that LGE was a significant predictor of the primary (p=0.003) (Fig.1) and secondary (p=0.001) EPs. Cox regression analysis showed that presence of LGE was associated with an increase in composite primary and secondary EPs (HR: 2.73, p=0.005 and HR: 2.77, p=0.002, respectively). Multivariate analysis showed that LGE was the only independent predictor of both EPs.

Conclusions:
In patients with known or suspected HF, the presence of LGE is an independent prognostic marker of adverse events, with incremental value to standard clinical information.
Abstract 8938: Heightened Renal Sympathetic Nerve Activity in Response to High Salt Intake After Renal Ischemia-Reperfusion Injury: Role Of TRPV1
Authors: Yu Shuang Q , Wang Donna H
Published: April 2024

Increased salt sensitivity occurs following ischemia-reperfusion (I/R) injury of the kidney. We test the hypothesis that renal sympathetic nerve activity is increased in response to high salt (HS) intake after I/R of the kidney, which can be prevented by activation of the transient receptor potential vanilloid type 1 (TRPV1) prior to renal I/R. Rats were fed a 0.4 % NaCl diet for 5 wks after I/R, following by a 4 % NaCl diet for 4 more wks in four groups: Sham, I/R, I/R+high dose capsaicin (HDC), and I/R+low dose capsaicin (LDC). TRPV1 was activated or down-regulated by s.c. injection of a low (1 mg/kg) or high (100 mg/kg) dose of capsaicin, respectively, 3 hrs before I/R. Renal TRPV1 protein expression was decreased after I/R and further reduced in I/R+HDC but unchanged in I/R+LDC compared to Sham (Sham: 0.44±0.04 vs I/R: 0.26±0.02 vs I/R+HDC: 0.17±0.01 vs I/R+LDC: 0.38±0.05, p<0.05). Systolic blood pressure and renal excretory function were not different among four groups 5 wks after I/R, but gradually elevated or deteriorated, respectively, when switched to HS for the remaining 4 wks in I/R and I/R+HDC but not I/R+LDC, with greater intensity in I/R+HDC ( p<0.05). At the end of HS treatment, afferent renal nerve activity in response to unilateral intra-pelvis administration of capsaicin was decreased in I/R and further suppressed in I/R+HDC but unchanged in I/R+LDC (Sham: 123±7 vs I/R: 81±9 vs I/R+HDC: 37±6 vs I/R+LDC: 120±13%, p<0.05). Efferent renal nerve activity in response to intrathecal administration of muscimol (3 nmol/kg), a selective activator of GABA-A receptors, was decreased in I/R and further suppressed in I/R+HDC but unchanged in I/R+LDC (Sham: -21±1 vs I/R: -42±3 vs I/R+HDC: -53±2 vs I/R+LDC: -25±4%, p<0.05). Urinary norepinephrine levels were increased in I/R and further elevated in I/R+HDC but unchanged in I/R+LDC (Sham: 785±98 vs I/R: 1311±98 vs I/R+HDC: 1731±140 vs I/R+LDC: 1018±85 ng/day, p<0.05). These data show that renal sympathetic drive is increased in response to HS intake after I/R, which can be prevented by TRPV1 activation prior to renal I/R, indicating that TRPV1 may prevent increased salt sensitivity after I/R via suppression of heightened renal sympathetic nerve activity.
Abstract 9015: Correlation between Spatial Repolarization and Peak-to-end of the T Wave on Transmural Left Ventricular and Body Surface Electrocardiographic Recordings
Authors: Izumi Daisuke , Chinushi Masaomi , Iijima Kenichi , Hasegawa Kanae , Sato Akinori , Furushima Hiroshi , Aizawa Yoshifusa
Published: April 2024

Background.
Previous studies showed that Tp-e is a marker of transmural dispersion of ventricular repolarization.

Objectives.
We studied the relationship between a) the interval between peak and end of the T wave (Tp-e) on local transmural electrograms (transmural Tp-e) or body surface ECG (surface Tp-e) and b) the intracardiac left ventricular (LV) repolarization during QT interval prolongation.

Methods.
Using a canine anthopleurin-A model, transmural LV electrograms were recorded via needle electrodes placed in the baso-anterior, mid-anterior, apico-anterior, baso-lateral, mid-lateral, and apico-lateral LV wall. Recovery time (RT) was calculated as an index of local repolarization at each transmural unipolar electrode.

Results.
RT was longer at the LV apex than that at the base, and longer in the lateral than in the anterior wall. A high correlation was found between transmural Tp-e and the transmural RT-dispersion (figure 1). On the other hand, surface Tp-e was correlated with total spatial LV RT-dispersion, though not with transmural RT-dispersion (figure 2). The slope of the linear correlation between surface Tp-e and total spatial LV RT-dispersion was 1.04 (P < 0.001), whereas betwwen surface Tp-e and averaged transmural RT-dispersion was 0.25 (P < 0.001). The shortest RT in the heart corresponded to the peak, whereas the longest RT coincided with the end of the T wave on the surface ECG.

Conclusions.
Surface Tp-e may overestimate the transmural dispersion of LV repolarization, and seems to express the special distribution of repolarization in the whole LV during iatrogenic QT interval prolongation.
Abstract 9018: Serial in vivo Imaging Reveals a Key Function for Splenic Monocytes in Infarct Healing
Authors: Leuschner Florian , Rauch Philipp J , Gorbatov Rostic , Marinelli Brett , Lee Won Woo , Sena Brena , Panizzi Peter , Libby Peter , Pittet Mikael J , Swirski Filip K , Weissleder Ralph , Nahrendorf Matthias
Published: April 2024

The splenic monocyte reservoir contributes substantially to acute inflammation, and these cells participate centrally in tissue repair after myocardial infarction (MI). We here investigated the relevance of the splenic reservoir monocytes for infarct healing and left ventricular remodeling.

Methods:
Mice received coronary artery ligation and splenectomy either on the day of MI or 3 days later, and were then followed by cardiac MRI (day 1 and 21 after MI, figure). On day 5 after MI, they underwent three-channel fluorescent molecular tomography (FMT-CT) to quantify uptake of a monocyte/macrophage-targeted fluorescent nanoparticle and a fluorescently labeled integrin probe, and activation of a protease sensor in the heart. Mice with coronary ligation but without splenectomy served as controls.

Results:
Removal of the spleen reduced accumulation of nanoparticles, indicating reduced monocyte/macrophage phagocytic activity in the infarct. Proteolytic potential and integrin expression were reduced as well, independent of splenectomy time (p<0.05 versus MI only, figure). Splenectomy at either time-point significantly impaired left ventricular ejection fraction on MRI (MI only, 50±6%; MI and immediate splenectomy, 32±4%; MI and splenectomy 3 days later, 36±4%; p<0.05 versus MI only) and resulted in a thinner scar (530±50μ m, 320±20μ m, 370±20μ m, p<0.05 versus MI only). Ex vivo analysis in additional cohorts corroborated in vivo imaging data.

Conclusion:
Removal of the spleen reduced monocyte-mediated healing biomarkers and resulted in infarct expansion and accelerated left ventricular remodeling. Thus, spleen-derived macrophages likely promote healing of the infarcting myocardium.
Abstract 9069: Matrix Metalloproteinase-9 (MMP-9), Myeloperoxidase (MPO), And Soluble Cd40 Ligand (sCD40L) Levels in Patients with Non-calcified Coronary Artery Plaques Without Significant Stenosis by Coronary Computed Tomography Angiography (CCTA)
Authors: Roy Sion K , Hou Zhi-hui , Lu Bin , Gao Yang , Jiang Shiliang , Jing Na , Chen Xi , Cong Xiangfeng , Budoff Matthew J
Published: April 2024

Objective:
We aimed to evaluate whether matrix metalloproteinase-9 (MMP-9), myeloperoxidase (MPO), and soluble CD40 ligand (sCD40L) are elevated in patients with non-calcified plaques without significant coronary artery stenosis. These are the plaques that have been called “vulnerable” and may lead to acute coronary syndromes (ACS).

Methods:
We retrospectively analyzed all subjects who underwent coronary computed tomography angiography (CCTA) at our center between January 2009 and May 2010. All patients were referred for chest pain. After excluding patients who had calcified coronary plaques or significant coronary artery stenosis (stenosis>50%), 174 patients were analyzed. Eighty-four patients who had non-calcified coronary plaques were enrolled in group A. Ninety patients who had no coronary plaque were enrolled in the normal control group (group B). The serum levels of MMP-9, MPO, and sCD40L were compared between the two groups. The relationship between these biomarkers and Framingham risk scores were analyzed. Receiver operating characteristic (ROC) curves were used to evaluate the ability of these biomarkers to predict the presence of non-calcified plaques.

Results:
A total of 128 non-calcified coronary plaques were found in 84 group A patients. The MMP-9 (641.33 ± 215.38 ng/ml vs 413.90 ± 182.01 ng/ml, p<0.001) and MPO values (1073.69 ± 478.20 ng/ml vs 705.18 ± 289.68 ng /ml, p<0.001) in group A were significantly higher than in group B. No significant difference was found in serum level of sCD40L between the two groups (8.65 ± 3.39 ng/ml vs 8.08 ± 4.00ng /ml, p=0.355). The Framingham risk score was significantly higher in group A than in group B (21 ± 5 vs 16 ± 4, p<0.001). The serum levels of MMP-9 and MPO showed significant correlation with Framingham risk score (r = 0.799, p<0.001; and r = 0.301, p<0.001), but not for sCD40L (r=0.072, p=0.345). In terms of predicting non-calcified plaque, the areas under the ROC curves of MMP-9, MPO and sCD40L were 0.802 (95%CI = 0.735-0.868, p<0.001), 0.738 (95%CI = 0.663-0.812, p<0.001), and 0.575 (95%CI = 0.489-0.661, p=0.086), respectively.

Conclusion:
The serum levels of MMP-9 and MPO positively correlated with Framingham Risk Score and were significantly increased in patients with non-calcified plaque.
Abstract 9095: Induction of Modulatory Calcineurin Inhibitory Protein 1 as a Potential Mechanism Leading to Cardiac Hypertrophy in the Cardiomyocyte-Specific Vitamin D Receptor Gene-Deleted Mouse
Authors: Chen Songcang , Law Christopher S , Grigsby Christopher L , Olsen Keith , Hong Ting-Ting , Zhang Yan , Yeghiazarians Yerem , Gardner David G
Published: April 2024

A growing body of epidemiological, clinical, and whole animal studies has shown that vitamin D deficiency is linked with increased risk of cardiovascular disease, including cardiac hypertrophy. Although global nuclear vitamins D receptor (VDR)-null mice display cardiac hypertrophy, the mice also demonstrate hypertension and secondary hyperparathyroidism, both of which are associated with cardiac hypertrophy. Therefore, it remains unknown as to whether the liganded VDR interacts directly with the cardiac myocyte to control hypertrophy. In an effort to address this issue, we have generated a mouse with selective deletion of the VDR gene in cardiomyocytes. Targeted deletion of exon 4 in the VDR gene resulted in an increase in myocyte size and left ventricular weight/body weight versus controls both at baseline and following chronic infusion of isoproterenol (ISO). There was no increase in interstitial fibrosis. These knockout mice demonstrated a reduction in end diastolic and end systolic volume by echocardiography, activation of the fetal gene program (i.e. increased ANP and alpha skeletal actin gene expression) and increased expression of the modulatory calcineurin inhibitory protein 1 (MCIP 1), a direct downstream target of calcineurin/NFAT signaling that plays an important role in cardiac hypertrophy. ISO treatment of neonatal rat cardiomyocytes resulted in a significant increase in MCIP 1 mRNA and protein levels and MCIP 1 gene promoter activity. Treatment with 1,25 dihydroxyvitamin D (VD3), a potent VDR ligand, resulted in partial suppression of the ISO-dependent increases in MCIP 1 expression and promoter activity. Renin gene expression was extremely low at baseline in the adult murine left ventricle and did not increase significantly in the left ventricles of cardiomyocyte-specific VDR knockout mice. Collectively, these studies provide the first demonstration that the VD3-VDR signaling system possesses direct, anti-hypertrophic activity in the heart. This activity may be linked to suppression of the pro-hypertrophic calcineurin/NFAT/MCIP 1 pathway. These studies identify a potential mechanism to account for the reported beneficial effects of VD3 in cardiac disorders associated with myocyte hypertrophy.
Abstract 9121: Intra-endoplasmic Reticulum Ca2+ Flow Recharges Preferentially to Subcompartments of ER at Caveolin-rich Cell Edges in Endothelial Cells
Authors: Isshiki Masashi , Fujita Toshiro
Published: April 2024

Subcellular distribution of caveolin-1, a marker protein of caveolae, is polarized especially in migrating or subconfluent endothelial cells (
Fig. 1
). In response to ATP, IP
3
production and Ca
2+
release originated at caveolin-1-rich cell edges (CRCE) and then propagated as spatiotemporally organized Ca
2+
waves (
Fig. 2
). Here in this study, we investigated subcellular Ca
2+
dynamics in the endoplasmic reticulum (ER) Ca
2+
stores by using confocal microscopy and an ER-targeted version of cameleon (D1ER), a GFP-based Ca
2+
-sensing protein. As expected, FRET imaging using an ER-targeted Ca
2+
sensor revealed that the ATP-mediated decrease in local intra-ER Ca
2+
concentration ([Ca
2+
]
er
) at CRCE was more rapid and larger than in other subdomains (
Figs. 2, 3
). Interestingly, the decreased [Ca
2+
]
er
at such CRCE more rapidly returned to the baseline in the presence of normal extracellular Ca
2+
. Even in the absence of extracellular Ca
2+
, when maximal ATP stimulation continued to decrease global [Ca
2+
]
er
, [Ca
2+
]
er
at CRCE exhibited the opposite incremental recharging. Removal of extracellular Ca
2+
or thapsigargin treatment did not affect such local recharging of Ca
2+
, suggesting no major roles of store-operated Ca
2+
entry (SOCE) or reuptake of released Ca
2+
into the ER by a Ca
2+
-ATPase. Thus, we conclude that the local ER Ca
2+
store comprises functional subcompartments at CRCE and that an ATP-induced [Ca
2+
]
er
decrease at the caveolin-1-rich region is preferentially recharged by intra-ER Ca
2+
flow from the other ER subcompartments (
Fig. 4
).
Abstract 9163: Head-to-head Comparison Between the Prognostic Role of Two Functional Tests in a Population of Elderly Patients with Chronic Heart Failure
Authors: Scardovi Angela Beatrice , De Maria Renata , Ferraironi Alessandro , Gatto Laura , Di Giacomo Tiziana , Renzi Marco , Ricci Roberto
Published: April 2024

Background
The six-minute walk test (6MWT) and the cardio-pulmonary exercise testing (CPx ) provide a valid assessment of functional performance in patients ( pts ) with HF but in elderly pts a comparison on prognostic validity of the 2 techniques has not been yet performed.

Aims:
We sought to compare the prognostic ability of the two functional tests in risk stratification of elderly CHF pts.

Methods:
We prospectively followed-up 170 stable HF outpatients on optimized medical therapy by using a thorough clinical, laboratory and instrumental evaluation, including the 6MWT and the CPX . The composite end-point was death or hospitalizations for cardiovascular causes.

Results
Mean age was 71±11 years, 28 % were female, 43% had ischemic heart disease, 18 % were in NYHA class III, 70% were on beta-blockers, 13% had an advanced diastolic disfunction, echocardiographic left ventricular ejection fraction ( LVEF ) was 44±13 %, mean BNP was 358±482 pg /ml . The mean distance covered during the 6MWT was 329±104 m. Peak workload was 71±11 watts, peak oxygen consumption (PVO2) was 13.2±4 ml/kg/min, the slope of the regression line relating ventilation to CO2 output, (VE/VCO2 slope) was 34±7 Exercise oscillatory breathing was found in 79 pts (46 %). During a median follow-up of 13 months, 18 patients died of cardiovascular causes and overall 51 met the combined end point of death or cardiovascular hospitalization. Distance walked correlated significantly to PVO2 (r=0.47, p<.0001). By Cox multivariable analysis, independent predictors of outcome were mean distance covered during the 6MWT (HR 0.996, CI 95% 0.992-0.999), LVEF (HR 0.962, CI 95% 0.938 - 0.985) and PVO2 (HR 0.883, CI 95% 0.790-0.987).

Conclusions:
Among elderly CHF pts 6MWT is not only a simple and reliable first-line test for quantification of exercise intolerance but retains a prognostic value independent of CPX derived PVO2. This is a cornerstone in functional assessment because the 6MWT is widely diffused, safe and may be more feasible than CPX in a population of elderly HF pts.
Abstract 9171: An Increase in Late Sodium Current Causes Junctional Tachycardia in Mice Expressing an LQT3 SCN5A Mutant Na
+
Channel
Authors: Wu Lin , Liu Gongxin , Yang Bo , Li Hong , Hoyer Kirsten , Shryock John C , Belardinelli Luiz
Published: April 2024

Background:
Junctional tachycardia (JT) is predominantly seen in young patients, where it is associated with significant morbidity and mortality and poor response to drug therapy. We documented JT in mice with the cardiac gain-of-function SCN5A mutation N1325S and its inhibition by ranolazine, suggesting that enhancement of the late Na
+
current (late I
Na
) is a novel cause of JT.

Methods:
In N1325S mutant and wild type mice, an eight-channel surface ECG was recorded weekly for 15 weeks. Intracardiac electrograms from catheterization of intact animals and studies of isolated hearts were performed.

Results:
JT occurred in an age-dependent manner in N1325S mutant but not in wild type mice. The number of N1325S mice with JT increased from 0 % at 3 weeks or less of age to 13.7, 46.6, 79.3, 89.1 and 100 % at 4, 5, 7, 10 and 15 weeks of age, respectively, and heart rate (HR) increased from 520±22 bpm at 5 weeks to 598±14 bpm at 15 weeks (n=58, p<0.01). In contrast, in littermate wild type mice HR was 463±12 bpm and sinus rhythm was maintained. HR was significantly higher at all ages in N1325S mice with JT than in wild type mice (n=45, p<0.01). JT in N1325S mouse isolated hearts and in intact animals could not be terminated by programmed atrial stimulation (n=7), suggesting that reentry is unlikely to be the mechanism underlying the JT. In isolated hearts, the late I
Na
inhibitors ranolazine (1-30 µM, n=6), TTX (0.1-1 µM, n=8) and flecainide (0.1-1 µM, n=3) slowed the rate of the JT and converted JT to sinus rhythm in a concentration-dependent manner. Results from the intracardiac EP study confirmed the JT in N1325S mice, and the JT was terminated by intraperitoneal administration of ranolazine (15-30 mg/kg).

Conclusion:
The gain-of-function cardiac SCN5A mutation N1325S is associated with JT in mice. An enhanced late I
Na
is a novel mechanism for JT. Drugs that inhibit late I
Na
may be effective in treating JT in patients with enhanced late I
Na
.
Abstract 9176: Enhancing Lysosome Biogenesis Attenuates Bnip3-induced Cardiomyocyte Death
Authors: Ma Xiucui , Godar Rebecca , Diwan Abhinav
Published: April 2024

Rationale:
Hypoxia-inducible pro-death protein, BNIP3 (Bcl2 and nineteen-kilodalton interacting protein-3) provokes mitochondrial permeabilization causing cardiomyocyte death in ischemia-reperfusion injury. Inhibition of cardiomyocyte autophagy accelerates Bnip3-induced cell death, by preventing removal of damaged mitochondria. We tested the
hypothesis
that stimulating cardiomyocyte autophagy will attenuate Bnip3-induced cell death.

Methods and Results:
Neonatal rat ventricular myocytes were adenovirally transduced with Bnip3 (or LacZ as control; at multiplicity of infection = 100); and autophagy was stimulated with rapamycin (100nM) added at baseline and 24 hours; and cell death was assessed at 48 hours. Bnip3 expression increased autophagosome abundance 15-fold and caused a 3.5-fold increase in cardiomyocyte death as compared with control. Rapamycin treatment of Bnip3 expressing cells led to further increase in autophagosome number without affecting cell death. Bnip3 expression led to accumulation of autophagosome bound LC3-II and p62; and increase in autophagosomes but not autolysosomes (assessed with dual fluorescent mCherry-GFP-LC3 expression); indicating autophagosome accumulation with impaired flux through the macroautophagy pathway. Bnip3 did not provoke lysosome permeabilization or alter lysosome pH; and BNIP3 protein did not localize to lysosomes by subcellular fractionation. Rather, Bnip3 expression caused a decline in lysosome numbers with decreased expression of lysosomal proteins-LAMP1 and LAMP2, indicating lysosome consumption and consequent autophagosome accumulation with Bnip3-induced autophagy. Forced expression of TFEB, a transcription factor that promotes lysosome biogenesis, increased lysosome numbers; reduced LC3-II/LC3-I ratio and p62 abundance, increased autolysosome to autophagosome ratio (indicating restored autophagic flux); and attenuated death in cells expressing Bnip3.

Conclusion:
Bnip3 expression causes cardiomyocyte death with impaired autophagic flux secondary to reduced lysosome numbers indicating consumption in the autophagy process. Forced expression of TFEB, a lysosomal biogenesis factor, restores autophagic flux and attenuates Bnip3-induced cell death.
Abstract 9178: Cell-Based Prostacyclin Gene Therapy Prevents Pulmonary Arterial Hypertension
Authors: Zhou Lei , Cheng Zhiqiang , Vanderslice Peter , So Shuiping , Ruan Kehe , Willerson James T , Dixon Richard A
Published: April 2024

Objectives:
Intravenous prostacyclin is approved for the treatment of pulmonary arterial hypertension (PAH). However, it has limitations of a short half-life, the permanent placement of an intravenous catheter and substantial annual cost. We hypothesized that cell-based prostacyclin gene therapy may provide sustained therapeutic effects without the aforementioned limitations.

Methods and Results:
Since prostacyclin is produced from arachidonic acid by the enzymes cyclooxygenase (COX) and prostacyclin synthase (PGIS), we generated a vector expressing COX isoform 1 (COX1) and PGIS fusion protein that is capable of producing prostacyclin from arachidonic acid. Endothelium-like progenitor cells (ELPCs) from syngenetic Fisher 344 rats were transfected with COX1-PGIS expressing vector and lentivirus expressing nuclear localized red fluorescent protein (nuRFP). The engineered ELPCs expressing COX1-PGIS and nuRFP were tested in a monocrotaline (MCT) induced rat PAH model. Twenty-five days after cell transplantation, 48% of transplanted ELPCs resided in the lungs. MCT induced an increase in right ventricular systolic pressure (RVSP) compared to normal controls (51.9 ±2.2 mmHg vs. 26.3 ± 1.5 mmHg, p<0.01). The increase in RVSP was significantly attenuated by treatment with ELPCs alone (40.9 ±1.6 mmHg, p<0.01) or with ELPCs engineered to express the COX1-PGIS transgene (35.9 ±1.6 mmHg, p<0.01). Engineered ELPCs were significantly more effective than ELPCs alone in preventing the increase in RVSP (p<0.05). Right ventricle hypertrophy (right ventricle vs. left ventricle plus septum weight ratio) was reduced by treatment with ELPCs (28.8±0.8% vs. 36.5±3.1%,
p
<0.01) or engineered ELPCs (30.5±0.9% vs. 36.5±3.1%,
p
<0.01). Lung vessel thickness index increase (reflecting intima thickening and medial smooth muscle hypertrophy) was attenuated by treatment with engineered ELPCs (78.1±3.1% vs. 90.1±4.1%,
p
<0.05).

Conclusions:
COX1-PGIS expressing ELPCs prevented MCT-induced PAH and showed enhanced efficacy over ELPCs alone. The one time cell delivery offered sustained therapeutic efficacy for at least 25 days, which may provide a promising option for patients with PAH.
Abstract 9196: Assessment of Left Ventricular Mass in Hypertrophic Cardiomyopathy Patients Bb Real-Time 3-Dimensional Echocardiography in Single-Beat Capture Image; Validation with Cardiac Magnetic Resonance Imaging
Authors: Chang Sung-A , Lee Sang-Chol , Kim Eun-Young , Hahm Seung-Hee , Sohn Myung-Kyun , Kim Eun-young , Park Sung-Ji , Choi Jin-Oh , Hahn Joo-Yong , Park Seung Woo , Choe Yeon Hyeon , Oh Jae K
Published: April 2024

Background:
Left ventricular (LV) mass is an important prognostic factor in hypertrophic cardiomyopathy (HCM). LV mass can be easily accessed by M-mode or 2D echocardiography; however it includes assumption and might be incorrect in LV with asymmetricity. Real time three dimensional echocardiography (RT3DE) has been introduced as an accurate method to assess the LV mass and recently, RT3DE by single beat capture with online analysis program has been introduced. We validated LV mass using new RT3DE technique compared to cardiac magnetic resonance (CMR).

Method:
Thirty six HCM patients were consecutively enrolled and 3 patients were excluded due to poor RT3DE images. All the patients underwent CMR and RT3DE within the same day. LV mass was derived from the following methods; the ASE formula (M-mode mass), truncated ellipsoid method by 2D echocardiography (2D mass) and RT3DE (RT3DE mass). RT3DE image was acquired using the SC2000 System. The LV mass data were compared with the LV mass analyzed by CMR.

Results:
Mean frame rate of RT3DE was 13.1±2.3 frame/second. Pearson's interclass coefficient (ICC) showed close correlation of RT3DE mass and CMR mass (r=0.92 and p< 0.0001). However, M-mode mass and 2D mass had smaller ICC when compared with CMR (r=0.50, p=0.01 and r=0.78, p<0.001) Bland-Altman analysis showed reasonable limits of agreement with small positive bias (15.1). Bias was greater in M-mode LV mass and 2D LV mass (-39.1 and 21.2)

Conclusions:
LV mass measured by single-beat captured RT3DE is a feasible and accurate method in HCM patients. Because LV shape is asymmetrical in many subjects with HCM, LV mass derived from 2D or M-mode is much more inaccurate than symmetrical LVs. Correct assessment of LV mass using single-beat captured RT3DE will be useful in HCM patients in real clinical practice.
Abstract 9197:
In Situ
Stem Cell Therapy Using Human Adipose Tissue-Derived Multi-lineage Progenitor Cells Combined with HMG-CoA Reductase Inhibitor Synergistically Reduce Serum Cholesterol Level in Hyperlipidemic Watanabe Rabbits
Authors: Okura Hanayuki , Saga Ayami , Soeda Mayumi , Tani Jyunko , Moriyama Mariko , Moriyama Hiroyuki , Yamashita Shizuya , Ichinose Akihiro , Tahara Shinya , Hayakawa Takao , Matsuyama Akifumi
Published: April 2024

Background
: Familial hypercholesterolemia (FH) is an autosomal co-dominant disease characterized by high concentrations of pro-atherogenic lipoproteins and premature atherosclerosis. We examined the response to the combination of
in situ
stem cell therapy using human adipose tissue-derived multi-lineage progenitor stem cells (hADMPC) and HMG-CoA reductase inhibitor in the Watanabe heritable hyperlipidemic (WHHL) rabbit, an animal model of homozygous FH.

Methods
: WHHL rabbits received hADMPC via the portal vein, followed by a course of immunosuppressive therapy to avoid xenogenic rejection.
In situ
reprogramming of the hADMPC into hepatocytes was examined by immunohistochemistry and QT-PCR analysis. Lipid profiles were examined before-transplantation, after-transplantation and/or after transplantation followed by 4 weeks of treatment with HMG-CoA reductase inhibitor, pravastatin. LDL clearance was examined at the end of the study by125I-LDL turnover studies.

Results
: The hADMPC were integrated into the hepatic parenchyma after transplantation, and expressed human hepatocyte markers such as albumin, indicating that these cells were reprogrammed into hepatocytes-like cells
in situ
. hADMPC-transplantation reduced serum cholesterol levels and improved LDL turnover. Transplantation followed by 4-week treatment with pravastatin further reduced serum cholesterol levels compared with untreated rabbits. LDL clearance was significantly augmented in the pravastatin-treated rabbits.

Conclusion
: Transplantation of hADMPC corrected the metabolic defects and the effects were augmented by statins in WHHL rabbits, in which no significant effects were observed by statins.
In situ
stem cell therapy combined with other drugs is a potentially useful strategy for FH.
Abstract 9218: Troponin Elevation, Ischemic Electrocardiographic Changes and Prognosis after a Postoperative Myocardial Infarction
Authors: Garcia Santiago , Marston Nicholas , Brenes Jorge , Adabag Selcuk , Yannopoulos Demetris , Kuskowski Michael , McFalls Edward O
Published: April 2024

Background:
In the postoperative period the majority of myocardial infarctions are clinically silent and its diagnosis relies heavily on a biomarker elevation. Although an elevated troponin level following vascular surgery is associated with a poor long-term outcome, the utility of abnormal EKG changes as additional prognostic information is unclear.

Methods:
Single center registry of 435 patients undergoing high-risk vascular surgery at the Minneapolis VA Medical Center between January 2005 and December 2009. Blood was obtained in all patients in the first two days following vascular surgery and the troponin I levels were measured by the Dade Behring Dimension Analyzer. Those values that exceeded the URL were categorized as either LOW (+) (≥ the URL but < 3 times the URL) or HIGH (+) (≥ 3 times the URL). Electrocardiograms obtained before the operation and within the first 3 postoperative days were reviewed by 2 independent cardiologists and classified as ischemic (ST-segment depression, ≥ 2 mm T-wave inversion) or non-ischemic. Long-term survival was retrieved using BIRLS.

Results:
The mean age of the population was 68±8 and the most common vascular problem was an expanding abdominal aneurysm (49%). Eighty-one (18.6%) patients were classified as HIGH (+) and 104 (24%) as LOW (+) with regard to troponin values. Thirty-one (7%) patients had evidence of myocardial ischemia on electrocardiography. An increase in mortality was seen with incremental troponin values (p <0.001). However, the presence of electrocardiographic changes did not provide additional prognostic information to that conveyed by troponins in any category (p: 0.91, Figure).

Conclusions:
The requirement for an electrocardiographic correlate of myocardial ischemia to define a myocardial infarction appears to be insensitive in the post-operative period. Further, in the presence of a troponin elevation the incremental prognostic value of an ischemic ECG is minimal.
Abstract 9224: Depletion of Mature B cells by Deletion of BAFF Receptor Reduces Atherosclerosis in ldlr Knockout Mice
Authors: Sage Andrew P , Harrison James E , Baker Lauren A , Masters Leanne , Tsiantoulas Dimitris , Binder Christoph J , Mallat Ziad
Published: April 2024

Innate-like B1a cells may protect against atherosclerosis via production of natural anti-oxLDL IgM antibodies. However, we recently demonstrated that anti-CD20 antibody-mediated B cell depletion reduced murine atherosclerosis, suggesting some subsets of B cells could promote atherosclerosis. B cell activating factor (BAFF) and its cognate receptors, are important regulators of B cell survival and activation. Increased BAFF levels are associated with a number of autoimmune diseases. This study aims to characterise the effects of mature B cell loss on atherosclerosis. We analysed aortic root atherosclerosis, serum anti-oxLDL antibody levels and immune cell phenotypes in male ldlr-/- mice transplanted with control (WT) or BAFF receptor (BAFFR)-/- bone marrow and fed a high fat diet for 6 weeks. Ldlr/BAFFR-/- chimeric mice had significantly reduced levels of mature B cells (B220+ IgM+) in the spleen, blood, bone marrow and peritoneum, but no difference in peritoneal B1a cells (B220+ IgM+ CD11b+ CD5+). Despite a non-significant trend towards increased serum total cholesterol (6.65±0.72 g/l vs 6.03±0.72 in controls), aortic root atherosclerosis levels were reduced by 33% in ldlr/BAFFR-/- mice, an effect accompanied by a reduction in IgG but not IgM antibodies to malonaldehyde modified-LDL and reduced CD4+ T cell proliferation in vitro. However, there was no apparent difference in Treg levels or function, and no changes in blood Ly6C monocyte subsets. Splenic dendritic cells from ldlr/BAFFR-/- mice displayed reduced CD40 and MHC Class II expression, suggesting impaired activation in the absence of B cells. Deficiency in mature B cell levels reduced atherosclerosis and circulating levels of anti-oxLDL IgG, potentially linked to impaired pro-inflammatory dendritic cell maturation and T cell activation. These results support the notion that whereas B1a cells may protect against atherosclerosis by production of protective natural anti-oxLDL IgM antibodies, other B cell subsets could play pathogenic roles. This study provides important insight into the potential effects of therapies targeting B cells and/or BAFF on atherosclerosis.
Abstract 9237: Spectrum of Constrictive Pericarditis: 10-Year Experience
Authors: Mayer Alexander , Jan M. Fuad , Mori Naoyo , Kostopoulos Louie , Kress David C , Kleinman Leonard H , Allaqaband Suhail , Bajwa Tanvir , Paterick Timothy E , Tajik A. Jamil , Khandheria Bijoy K
Published: April 2024

Introduction:
Contemporary data on clinical presentation and outcomes of constrictive pericarditis (CP) in a community setting is lacking. We investigated the clinical spectrum of CP in a real-world setting.

Hypothesis:
Diagnosis of CP in contemporary clinical practice is difficult and frequently requires multimodality testing, with possible impact on clinical outcomes.

Methods:
A retrospective cohort of patients with surgically proven CP from January 2000 to December 2009 was studied. Baseline characteristics, clinical presentation, radiological imaging, cardiac catheterization and echocardiographic examinations were reviewed.

Results:
A total of 43 patients (median age 67; 76.7% male) were identified during the 10-year period. The majority presented with dyspnea (91%) and peripheral edema (72%), while anasarca and ascites were present in 33% of patients. Calcification on chest X-ray was present in 17% (5 of 29 cases), while catheterization hemodynamics suggested CP in 81% (25 of 31 cases). Computed tomography and/or magnetic resonance imaging showed pericardial thickening in 67% (20 of 30 studies). A specific etiology was found in 67% of the cohort (figure). Combined pericardiectomy with other cardiac surgery was undertaken in 35%. The perioperative 30-day mortality rate was 16%. At a median follow-up of 9 months, survival rate excluding perioperative mortality was 72%. Depressed ejection fraction (<40%) was a predictor of perioperative mortality (odds ratio: 8.27, 95% confidence interval [CI]: 1.41-48.54; p=0.019), while prior cardiac surgery was associated with reduced long-term survival (odds ratio: 6.82, 95% CI: 1.47-31.61; p=0.014).

Conclusions:
Our findings reaffirm the complexity of diagnosing constrictive pericarditis in contemporary medical practice. Early suspicion in clinical groups at risk for constrictive pericarditis and prompt surgical intervention prior to systolic dysfunction may improve outcomes.
Abstract 9241: High Sugar Intake May Improve Survival and Does Not Adversely Affect Cardiac and Metabolic Dysfunction in Genetic Cardiomyopathy
Authors: Hecker Peter A , Galvao Tatiana F , O'Shea Karen M , Brown Bethany H , Hendersen Reney , Riggle Heather , Gupte Sachin A , Stanley William C
Published: April 2024

High sugar intake increases the risk of heart disease in humans, and in some animal models of hypertension it increases oxidative stress and accelerates the development of heart failure. Recent studies suggest that glucose 6-phosphate dehydrogenase (G6PD) may be responsible for ROS generation, as it produces NADPH, which is used by NADPH oxidase to produce superoxide, while on the other hand it can facilitate the removal of reactive oxygen species (ROS) via the glutathione pathway. We hypothesized that a high sugar diet would increase flux through G6PD to increase myocardial [NADPH] and ROS production, and accelerate cardiac dysfunction and death. Cardiomyopathic TO-2 hamsters, a nonhypertensive model of genetic cardiomyopathy, were fed a either a high starch/sugar free diet or a high sugar diet (57% of energy from fructose +sucrose; n=12/group for echocardiography and biochemical analysis; n=30/cardiomyopathic group and n=10 healthy controls for survival analysis). However, after 24 weeks, the high sugar diet alleviated the decrease in ejection fraction associated with cardiomyopathy, and there was a strong trend for high sugar intake to increase survival (p=0.087)(Figure). High sugar intake increased left ventricular superoxide production, but did not affect [NADPH] or lipid peroxidation products. Cardiomyopathy resulted in metabolic abnormalities including decreased left ventricular mitochondrial oxidative enzyme activities, high circulating glucose, triglycerides and free fatty acids and decreased insulin, however the high sugar diet did not affect any of these parameters. These results indicate that despite a sugar-induced increase in superoxide production, there was no worsening of cardiac function or survival. In contrast, the high sugar diet improved systolic dysfunction and show a strong trend for prolonged survival.
Abstract 9248: GATA-4 Gene Transfer Increases Mesenchymal Stem Cell Mediated Myocardial Salvage Through Regulating Expression of miRNAs
Authors: Yu Bin , Pasha Zeeshan , Wang Yigang , Ashraf Muhammad , Xu Meifeng
Published: April 2024

Recent studies have provided increasing evidence that microRNAs (miR) play an important role in ischemic heart repair. We have previously reported that GATA-4 gene transfection increases mesenchymal stem cells (MSC) mediated cardioprotection. In this study, we investigated whether the cardioprotective effect of MSC overexpressing GATA-4 was associated with regulation of miR.

Methods and Results:
MSC were transduced with GATA-4 (MSC
GATA-4
) using the murine stem cell virus (pMSCV) retroviral expression system, control cells were transduced with empty vector (MSC
Null
). The expression of miR in MSC was assessed by miR microarray and quantitative real-time PCR. Primary cultured cardiomyocytes (CM) were obtained from neonatal rat ventricles. Hypoxic treatment was used to mimic ischemic injury. The cardioprotection in vitro of MSC
GATA-4
was examined through measurements of Lactate dehydrogenase release, MTT intake, and Annexin-V staining. To further determine the effect of MSC
GATA-4
on ischemic myocardium, MSC were injected into the peri-infarct region in myocardial infarction model in SD rats developed by ligation of the left anterior descending coronary artery (LAD). Overexpression of GATA-4 regulated several miR expression in MSC, especially, downregulation of miR-15b, miR-16, and miR-195 which belong to miR-15 family, and upregulation of miR-221/222. MSC
GATA-4
markedly protected CM against ischemic injury. Quantitative fluorescence
in situ
hybridization and immunostaining results showed that miR-221 as well as Bcl-w and VEGF, two proteins of target genes of miR-15 family, were transferred from MSC to CM. Gap junctions were observed between CM and MSC in a co-culture system. MSC
GATA-4
treated animals showed significantly improved cardiac function by echocardiography. Furthermore, histological studies revealed reduced infarction size.

Conclusions:
Overexpression of GATA-4 regulates miR expression in MSC, which plays an important role in protection of myocytes from ischemia.
Abstract 9254: Downregulation of SR Ca
2+
-ATPase as a Contributing Cause of Impaired Cardiomyocyte Basal and Beta-Adrenergic Regulation of [Ca
2+
]i with Myocyte Dysfunction in Monkeys with Chronic Heavy Alcohol Consumption
Authors: Wajih Nadeen , Cheng Heng-Jie , Zhou Peng , Daunais James B , Friedman David P , Little William C , Grant Kathleen A , Cheng Che Ping
Published: April 2024

Background
. Recent evidence indicates that the main effect of chronic alcohol ingestion is the loss of left ventricle (LV) contractility that progressively induces the development of alcoholic cardiomyopathy (ACM) and heart failure. However, the mechanisms underlying this sequela of events remain unclear. We tested the hypothesis that chronic alcohol-intake-caused progressive LV dysfunction is intrinsic to cardiomyocytes, and that impaired SR Ca
2+
-ATPase (SERCA 2a) function may play a key role.

Methods
. We compared the expression and activity of cardiac SERCA 2a and assessed myocyte contractile, [Ca
2+
]
i
transient ([Ca
2+
]
iT
) responses to isoproterenol (ISO, 10
-8
M), a β-adrenergic receptor (AR) agonist, in isolated myocytes obtained from biopsied LV tissues of cynomolgus monkeys: 6 normal controls (N) and 6 monkeys who chronically self-administered high levels of alcohol (HA) (4% alcohol, 3.3±0.7 g/kg) for 12 months.

Results.
Compared with controls, in alcoholic myocytes, SERCA 2a protein expression was decreased 56% (0.50 vs 0.89) and Ca
2+
-dependent activity of SERCA 2a was decreased 69% (32.7 vs 107.2 nmol/mg protein/min) (p<0.05). This change of SERCA 2a was associated with significant decreases in basal cell systolic amplitude (SA) (79%, HA: 6.4±1.3% vs N: 11.5±1.6%), velocity of shortening (dL/dt
max
) (38%, 64.8±5.0 vs 104.8±6.0 μm/s), velocity of relengthening (dR/dt
max
) (39%, 54.2±4.7 vs 88.4±5.3 μm/s), and a 34% prolonged time to peak of shortening. In the alcoholic myocytes, the peak [Ca
2+
]
iT
(33%, HA: 0.21±0.05 vs N: 0.31±0.05) was significantly reduced, but the diastolic [Ca
2+
]
iT
was increased and the decline of [Ca
2+
]
i
was slower. These alterations were accompanied by diminished ISO-stimulated positive inotropic effect. Compared with normal controls, in alcoholic cardiomyocytes, ISO (10
-8
M) significantly blunted the increases in SA (HA: 27% vs N: 60 %), dL/dt
max
(49% vs 79%), dR/dt
max
(24% vs 38%) and [Ca
2+
]
iT
(16% vs 32%).

Conclusions.
Chronic heavy alcohol intake causes downregulation of cardiac SERCA 2a with depressed myocyte contractile performance and abnormal myocyte basal and β-adrenergic regulation of [Ca
2+
]
i
. These findings support a mechanistic role of chronic alcohol-induced cardiac SERCA 2a dysfunction in ACM.