bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract Mo016: Atrial Fibrillation Outcomes in Carcinoid Tumor: A National Inpatient Sample (NIS) Study (2018-2020)
Authors: Gaddam Mrunanjali , Nanavaty Dhairya , Sanka Sujana , Thanneeru Priya , Iqbal Rabia , Jayakumar Jayalekshmi , Ginjupalli Manasa , Baddula Sowmya , Reddy Sarath
Published: October 2024

Background:
Carcinoid Tumor (CT) is a rare type of neuroendocrine tumor with a slow-growing nature. CT can affect different parts of the body, but it most commonly affects the gastrointestinal tract or the lungs. The average age of onset is in the early 60s, affecting around 1.5-1.9 people per 100,000 population. Atrial fibrillation (AF) has been associated with CT, however there is limited data about the outcomes associated with AF in the CT population. We aim to assess the impact of AF on mortality and complications in this population.

Methods:
The National Inpatient Sample database from 2018 to 2020 was analyzed to identify adult hospitalizations (age > 18) with a diagnosis of CT using appropriate ICD 10 codes. This population was stratified based on concomitant AF. Demographics and complication rates including venous thromboembolic diseases (VTE), acute heart failure (AHF) and acute ischemic stroke (AIS) were studied in these cohorts using a chi-square test for categorical and a t-test for continuous variables. Multivariate regression analysis was further performed to study the impact of AF on complications and mortality after adjusting for relevant confounders.

Results:
A total of 70504 adult hospitalizations with CT were identified of which 12.71% (N=8964) had AF. 54% of CT admissions were females and the mean age was 64 years. Hospitalizations with CT and AF had a higher rate of VTE, AHF and AIS (Table 1). Multivariate regression analysis revealed higher odds of AHF and AIS with AF in the subpopulation of adults with CT, while the odds of VTE were statistically insignificant. The odds of mortality with AF were also significantly higher in this subpopulation (Table 2).

Conclusion:
Our study concludes that atrial fibrillation portends a worse prognosis in hospitalizations with Carcinoid Tumor. It also shows a higher rate of AHF and AIS in this subgroup with statistically significant odds. Further studies should be done to study the impact of atrial fibrillation in Carcinoid Tumor patients and treatment guidelines for better management of atrial fibrillation in this vulnerable cohort should be formulated to improve patient outcomes.
Abstract Mo017: CXCR3: A Tumor-Conscious Target to Treat Immunotherapy-Induced Myocarditis
Authors: Sun Yin , Huang Yuhsin , Chou Harrison , Vitale Maria Rosaria , Lin Zachary , Zhu Han
Published: October 2024

Introduction:
Immune checkpoint inhibitors (ICIs, such as anti-CTLA-4 or anti-PD-1) have especially been effective in cancer therapies. However, ICIs treatment can result in myocarditis, the most serious complication of ICIs, which has a case fatality rate as high as 40%. Here, we investigate CXCR3 blockade for targeted treatment of myocardial inflammation in ICI myocarditis while considering concurrent tumor treatment. We hypothesize that CXCR3 blockade will have a direct effect on reducing CD8+ T-cell mediated cardiomyocyte cardiotoxicity without affecting tumor treatment.

Methods:
To study the impact of CXCR3 blockade on myocardial inflammation, we established an
in vitro
cardiomyocyte apoptosis model by co-culturing cardiomyocytes and MRL-WT mice CD8+ T-cells with/without ICI stimulation or MRL-
Pdcd1-/-
mice CD8+ T-cells. We then blocked CXCR3 to assess the effect on CD8+ T cell-mediated cytotoxicity against cardiomyocytes. To assess CXCR3 blockade in an
in vivo
model of ICI myocarditis accounting for tumor, we treated MRL mice inoculated with B16F1 melanoma cells with six doses of 400
µ
g each of anti-PD1 and anti-CTLA4 and investigated the effects of CXCR3-CXCL9/10 blockade on hearts and tumors.

Results:
In vitro
CD8+ T-cell and cardiomyocyte co-culture demonstrated mitigation of cardiomyocytes apoptosis with CXCR3 blockade (
Fig. 1 A
-
C)
, suggesting decreased CD8+ T-cell cytotoxicity with CXCR3 blockade.
In vivo
treatment with dual immunotherapy (anti-PD1/anti-CTLA4 monoclonal antibodies) in the tumor MRL mouse model demonstrated significant tumor volume reduction, which was not impacted by concurrent treatment with anti-CXCR3 or anti-CXCL9/10
(Fig. 1 D
-
F)
. Concurrently, myocarditis occurred in the group treated with immunotherapy alone, not in anti-CXCL9/10 or anti-CXCR3
(Fig. 1 G
-
H).

Conclusions:
CXCR3 blockade reduces CD8+ T-cell cytotoxicity against cardiomyocytes and mitigates myocarditis in an
in vivo
tumor ICI myocarditis mouse model without affecting anti-tumor ICI efficacy, positioning CXCR3 as a promising target for therapeutic intervention.
Abstract Mo022: Doxorubicin induces cardiomyopathy through Wnt5a-mediated induction of senescence
Authors: Sung Eun-Ah , Sadoshima Junichi
Published: October 2024

Doxorubicin (DOX) is a chemotherapeutic agent used to treat cancer, but its clinical use is restricted due to cardiotoxicity. Senescence is defined by resistance to apoptosis and a senescence-associated secretory phenotype (SASP). Elimination of senescent cells can improve cardiac dysfunction, suggesting that senescent cardiomyocytes (CMs) contribute to impaired heart function. Although DOX induces senescence in CMs, little is known about the mechanisms mediating DOX-induced senescence and cardiomyopathy. Wnt5a, a non-canonical Wnt ligand, is an important player in cardiac diseases and is upregulated in induced pluripotent stem cell (iPSC)-derived CMs from patients with heart failure induced by DOX chemotherapy. However, the role of Wnt5a in mediating DOX-induced cardiomyopathy remains elusive. Wnt5a protein expression was increased (4.4-fold, p<0.001) in mouse hearts with DOX-induced cardiomyopathy. Upregulation of Wnt5a following DOX treatment was also observed in neonatal rat CMs (NRCMs), and the degree of upregulation was more prominent in CMs (2.1-fold) than in non-CMs (1.1-fold). In NRCMs, Wnt5a induced senescent phenotypes, including increases in the p16 protein level, the number of γH2AX foci per cell and SA-β-gal activity. Wnt5a knockdown reduced DOX-induced increases in the p16 protein level in NRCMs, suggesting that Wnt5a mediates DOX-induced CM senescence. To assess the role of endogenous CM Wnt5a in mediating DOX-induced cardiomyopathy, we generated
Myh6
-cre
Wnt5a
fl/fl
(
Wnt5a
cKO
) mice, in which Wnt5a is knocked out in a CM-specific manner. DOX-treated
Wnt5a
cKO
mice showed little difference in ejection fraction (EF) compared to PBS-treated
Wnt5a
cKO
mice (56.64 ± 6.17% and 57.60 ± 5.23%), while DOX-treated
Wnt5a
fl/fl
mice showed a significant decrease in EF (34.63 ± 3.65%, p<0.0001). These results suggest that Wnt5a deletion in CMs impedes the progression of DOX-induced cardiac dysfunction, positioning Wnt5a as a novel therapeutic target for the prevention of DOX-induced cardiomyopathy.
Abstract Mo025: Noninvasive cardiac phenotyping in patients treated with chemo- and immunotherapy for breast cancer
Authors: Khashami Fatemeh , Dimitrov Ivan E , Fuetterer Maximilian , Kozerke Sebastian , Harrison Crystal , Huynh Mai , Park Jae Mo , Kovacs Zoltan , Malloy Craig , Henning Anke , Unni Nisha , Zaha Vlad
Published: October 2024

Current breast cancer diagnosis and treatment protocols achieve survival rates of>80% at 10 years.However, long-term cancer survivors have>4-fold higher incidence of cardiovascular complications, including heart failure.Early potentially reversible changes that may underlie downstream irreversible loss of mechanical function are unknown.Therefore, we aimed to test the feasibility of a noninvasive cardiac phenotyping protocol in patients undergoing treatment for breast cancer with doxorubicin, without or with immune checkpoint inhibitors, including multiparametric proton cardiac magnetic resonance(CMR) imaging and novel metabolic carbon13MR.

A comprehensive set of studies included conventional 1HCMR,as well as metabolic 13CCMR using hyperpolarized(HP)[1-13C] pyruvate, following an oral glucose load. 13CCMR with HP[1-13C] pyruvate allows the detection of downstream metabolites of injected pyruvate within the myocardium: bicarbonate from mitochondrial oxidation and lactate from anaerobic cytosolic metabolism.HP[1-13C]pyruvate was prepared using dynamic nuclear polarization in a commercial polarizer.Imaging and spectroscopy(MRS) of hyperpolarized pyruvate was conducted using a 13C transmit/receive Helmholtz loop-pair coil on a 3Tscanner.13C data were acquired from a short-axis slice, ECG-triggered in end-systole. ProtonCMR images were analyzed using Circle, and 13CCMR images were analyzed using MATLAB. The left ventricular mid-myocardium and blood pool were segmented for metabolite quantitation.

Baseline cardiac studies were performed in a consecutive series of 25 women treated for breast cancer. Of these 14(56%) were Caucasian, 3(12%) were Hispanic, 5(20%) Black, and 3(12%) Asian, with ages ranging 46±11 years.Patients received standard-of-care treatment plans based on the tumor type: 11 patients were treated with dose-dense anthracycline and cyclophosphamide, and 14 also received pembrolizumab. The comprehensive baseline phenotyping protocol is planned to be repeated after standard of care therapy in all patients. Baseline data are presented in Table1, with values reported as mean±standard deviation.

Noninvasive cardiac phenotyping, including dynamic detection of metabolic substrate utilization is feasible,without showing significant adverse effects,and is well tolerated in a diverse group of patients.Completion of this protocol post-oncological therapy may allow to detect early changes in cardiac function due to chemo-and immunotherapy in susceptible patients.
Abstract Mo027: Impact of Ventricular Arrhythmias On Outcomes of Patients with Follicular Lymphoma
Authors: Amin Hiral , Khalid Fizan , Dasu Kirti , Khalid Yaser , Dasu Neethi
Published: October 2024

Background:
Follicular lymphoma (FL) is typically a slow-growing form of non-Hodgkin lymphoma (NHL) that arises from B-lymphocytes. Large-scale studies are lacking for the outcomes of patients with ventricular arrhythmias and FL. We retrospectively reviewed FL patients with ventricular tachycardia utilizing the National Inpatient Sample (NIS) database. Our analysis aimed to identify risk factors that worsen outcomes in patients with FL and ventricular arrhythmias and evaluate the impact of ventricular arrhythmias on in-hospital outcomes of patients with FL.

Methods:
Data were extracted from the National Inpatient Sample (NIS) 2016-2019 Database. The NIS was searched for hospitalizations for adult patients with FL as the principal discharge diagnosis with and without ventricular arrhythmias as a secondary diagnosis using ICD-10 codes. The primary outcome was inpatient mortality. Multivariate logistic and linear regression analysis was used accordingly to adjust for confounders. STATA software was used for analysis.

Results:
This study included 15,795 patients with FL of which 225 had ventricular arrhythmias. Patients with both FL and an associated ventricular arrhythmia had higher inpatient mortality (OR 5.44, CI 2.48-11.93, p<0.0001), hospital length of stay (LOS) (+5.48 days, CI 3.27-7.68, p<0.0001) and total hospital charges (TOTHCG) (+$109,117.3, CI $65,702.9- $152,531.7, p<0.0001). In this patient population, the secondary analysis revealed that mortality was increased if patients had a cardiac arrest (OR 25.62, CI 1.36-484.48, p<0.031). LOS was increased in the presence of an acute kidney injury (+0.34 days, 0.04-0.64, p<0.026).

Conclusions:
Our study revealed that patients with FL and ventricular arrhythmias had increased mortality, hospital LOS, and TOTHCG, as well as much higher rates of complications, including cardiac arrest and acute kidney injury, compared to those without ventricular arrhythmias. Efforts to prevent, monitor, and aggressively manage ventricular arrhythmias in patients with FL will improve overall outcomes.
Abstract Mo028: Persistence of Fetal Cardiac Troponin T Modulates Disease Severity in Anthracycline-Induced Cardiomyopathy
Authors: Lynn Melissa , Vasquez Catherine , Pineda JR Exequiel , Klass Matthew , Tardiff Jil
Published: October 2024

Anthracyclines are a key component in the management of pediatric cancers long recognized to carry significant risk of dose-dependent cardiotoxicity. Despite advancements in clinical management, considerable variation in the incidence of cardiotoxicity persists across dosing regimens suggesting modifiers exist. Recently, changes in the splicing of TNNT2, the gene encoding cardiac troponin T (cTnT), were postulated to contribute to anthracycline cardiotoxicity, potentially providing a direct link to the myofilament. Previous studies in our lab have demonstrated that the fetal isoform, cTnT1, is a potent modifier of cardiac function contributing to disease heterogeneity in animal models of cardiomyopathies. Thus, we hypothesize that the persistent expression of cTnT1 predisposes a subset of the population to anthracycline cardiomyopathy. Using molecular dynamics simulations (MD) and isothermal titration calorimetry (ITC), we assessed a range of anthracyclines for their potential to bind the cardiac thin filament (CTF). MD calculated Glide scores showed direct binding to the troponin complex. ITC indicated that this binding occurs at an order of magnitude higher affinity in complexes containing cTnT1. Stopped-flow kinetics of cTnT1 CTFs exposed to Doxorubicin showed an additive reduction in calcium dissociation rates, reinforcing our observations of direct binding to the CTF. Longitudinal 2D echocardiography of Doxorubicin treated mice (3mg/kg/week) indicated that both male and female cTnT1 mice exhibit an additive, dose-dependent reduction in cardiac systolic function compared to non-transgenic (NT) littermates. Consistent with clinical data, female mice exhibited an earlier reduction in % fractional shortening than males as well as delayed recovery after treatment cessation. Transcriptional profiling of mice treated with Doxorubicin revealed a 2- to 7-fold additive increase in type I and type II interferon signaling in cTnT1 mice above that observed in treated NT littermates. These data suggest that cTnT1 may increase binding of anthracyclines at the myofilament, eliciting accelerated cardiac dysfunction, and represent a unique, targetable genetic risk factor involved in anthracycline cardiotoxicity.
Abstract Mo030: Deep learning based multi-omics model for prediction of outcomes in HFpEF and HFmrEF
Authors: Fisch Sudeshna , Jha Alokkumar
Published: October 2024

Introduction:
Heart failure with preserved ejection fraction (HFpEF) presents a unique challenge in cardiology due to its diverse etiology and clinical presentation. Our study introduces a cutting-edge integrated deep learning model that combines multi-dimensional datasets, encompassing genetic variants from GWAS, cardiac structural and functional assessments from MRI, and electrophysiological data from ECGs, along with comorbidity profiles including CKD and LFT.

Research Questions:
Can a deep learning model that integrates multi-dimensional datasets accurately predict HFpEF risk?

How does the inclusion of different types of data (genetic, MRI, comorbidity) affect the model's predictive accuracy?

Goals:
To develop a deep learning model that accurately predicts HFpEF risk

To assess the impact of different types of data on the model's predictive accuracy.

Methods:
The model employs a graph convolutional multi-model deep learning approach to dissect the intricate interplay between genetic variants from GWAS, cardiac structural and functional assessments from MRI, electrophysiological data from ECGs, and comorbidity profiles including CKD and LFT.

Results:
The baseline genetic model achieved a PRS of 2.04 and an outcome accuracy of 81%. The incorporation of MRI features improved the outcome accuracy to 85.91%. The inclusion of comorbidities such as CKD and T2D resulted in the highest outcome accuracy of 88.57%.

Discussion:
The results suggest that the inclusion of MRI features and comorbidities improves the model's predictive accuracy. This model holds significant promise for clinical adoption and the advancement of personalized treatment strategies.
Abstract Mo031: Tissue deficiency and altered eicosanoids levels in rodent and human heart failure.
Authors: Kala Petr , Mikula Jan , Hnat Tomas , Miklovic Matus , Skaroupkova Petra , Vanourkova Zdenka , Kotaska Karel , Ostadal Petr , Melenovsky Vojtech , Cervenka Ludek
Published: October 2024

Introduction:
The role of eicosanoids, especially epoxyeicosatrienoic acids (EETs), metabolites of arachidonic acid with cardio-renal activity, in heart failure (HF) remains unclear.

Hypothesis:
Altered eicosanoids turnover, both in rodent and human heart failure, is a part of the pathophysiology of HF and contributes to poor prognosis.

Methods:
We measured active EETs and their biologically inactive metabolites, dihydroxyeicosatrienoic acids (DHETs) in the left ventricle (LV) and renal tissue obtained from a rodent heart failure model induced by aortocaval fistula (ACF). We measured protein expression of CYP2C23 and CYP2J3 in the kidney cortex and LV tissue by Western blot analysis to evaluate EETs production and mRNA expression of soluble epoxide hydrolase (sEH), the enzyme responsible for the degradation of EETs to DHETs. In the translational part, firstly, we enrolled 50 patients with HF to measure plasma 14,15-epoxyeicosatrienoic acid (14,15-EET) and 14,15-dihydroxyicosatrienoic acid (14,15-DHET) levels using commercial ELISA kits and compared them with 25 age- and sex-matched controls. Secondly, 11 consecutive patients with HFrEF indicated to cardiac resynchronization therapy (CRT) were enrolled to measure plasmatic 14,15-EET and 14,15-DHET levels in venous, arterial, and coronary sinus (CS) blood samples and correlate them with N-terminal pro-B-type natriuretic peptide (NT-proBNP) from the same compartments.

Results:
ACF rats exhibited tissue deficiency of EETs in the LV and kidney compared to controls, probably mainly caused by increased EETs degradation by sEH (unchanged expressions of CYP2C23 and CYP2J3, increased mRNA of sEH and EETs/DHETs ratio). In humans, both of the measured eicosanoids were significantly higher in the HF group: 14,15-EET (91.3 ±25.7 vs. 64.95 ±35.4 ng/ml) and 14,15-DHET (10.58 ±2.06 vs. 9.07 ±1.60 ng/ml), p for both < 0.001. HF patients with 14,15-EET levels less than 60 ng/ml had worse short term mortality compared to those above. In CS, NT-proBNP levels negatively correlated with plasmatic 14,15-EET levels (r = -0.63, p = 0.03) and positively with the DHET/EET ratio (r = 0.73, p = 0.02). Plasmatic 14,15-EET nor 14,15-DHET levels in measured compartments did not differ statistically (p = 0.21, p = 0,64, respectively). In individual patients, the levels of both eicosanoids correlated across all compartments.

Conclusions:
Tissue deficiency of active eicosanoids and their altered turnover may play an important role in HF pathophysiology.
Abstract Mo036: DNA Damage and Repair in Patients Undergoing Myocardial Perfusion Single-Photon Emission Computed Tomography
Authors: Lorenzo Andrea , Santos Fernandes Maria Clara dos , Arpini Anna Paula , Sabioni Leticia , Dias Glauber
Published: October 2024

Background:
As medical imaging has continuously grown, patient exposure to ionizing radiation and the risks associated with it are important issues. Myocardial perfusion single-photon emission computed tomography (MP-SPECT) is one of the most frequently performed noninvasive cardiac imaging tests, generating concern about the potentially excessive radiation exposure for patients, including the cumulative doses of lifetime radiation. even though the individual levels of radiation exposure are considered low.

Aim:
To evaluate DNA damage and DNA repair markers after MP-SPECT.

Methods:
Thirty-two patients undergoing Tc-99m sestamibi MP-SPECT (mean injected Tc-99m sestamibi dose: 15.1 mCi) were studied. Peripheral blood was collected before radiotracer injection at rest and 60-90 minutes after injection. The comet assay (single-cell gel electrophoresis) was performed with blood lymphocytes to detect DNA strand breaks, which appear as DNA fragmentation (the comet tail; Figure1). Images of fluorescence microscopy were analyzed using the Comet Assay Software Project Lab (CASPLab 1.2.3 beta 2). Three parameters were evaluated: the percentage of DNA in the comet tail, tail length, and tail moment (the measure of migratory DNA and number of fragments). Quantitative PCR (qPCR) was performed to evaluate the expression of five genes related to signaling pathways in response to DNA damage and repair (ATM, ATR, BRCA1, CDKN1A, XPC). Data are expressed as medians, and Wilcoxon or Mann-Whitney tests were employed for statistical analysis. A p-value <0.05 was considered statistically significant.

Results:
Figure 2 shows pre- and post- radiation exposure comet assay parameters. After radiotracer injection, there was a 10.7% increase of the DNA percentage in the tail (pre-exposure median 2.185 vs post-exposure median 2.418, p<0.0065). Tail length increased 6.7% (15.0 pre-exposure vs 16.0 post-exposure, p<0.0034). Tail moment increased 27.5% (0.3177 pre-exposure vs 0.4050 post-exposure, p<0.0001). qPCR did not reveal increased expression of any gene after radiation exposure.

Conclusion:
An increase in DNA damage was detected after a single radiotracer injection for MP-SPECT, yet unaccompanied by activation of repair genes. This may suggest that DNA damage is not large enough to trigger intense repair responses and might not result in biologically significant DNA damage.
Abstract Mo041: Bile Acid Dysregulation in Response to Right Heart Failure and Hepatic Congestion
Authors: Park Arick , Yang Bin , Parvathaneni Adeesh , Fu Christina , Byrnes Kathleen , Haeusler Rebecca , Schilling Joel
Published: October 2024

Introduction:
Right heart failure (RHF), the result of impaired RV contractility and/or severe right-sided valvulopathies, is a clinical syndrome that commonly results in chronically elevated central venous pressures and hepatic congestion. Hepatic dysfunction in patients with heart failure portends a poor prognosis. In part, this may be due to the liver’s pivotal role in bile acid synthesis and processing. In addition to the classic role of a digestive surfactant, bile acids serve as important and dynamic signaling molecule. The present study characterizes a unique bile acid profile found in patients with RHF.

Research Question:
We hypothesize that RHF and hepatic congestion results in a dysregulation of bile acids. These untoward changes in bile acids concentrations may provide both important prognostic value and novel mechanistic pathways in congestive liver disease.

Aims:
1) To characterize systemic and hepatic vein bile acid concentrations in patients with right heart failure. 2) To phenotype a mouse model of hepatic congestion and understand the mechanistic effects of specific bile acids on liver biology

Methods:
We enrolled a total of 60 patients who were referred for right heart catheterization (RHC). Patient demographics, echocardiograms, and routine laboratory tests were captured at enrollment. Blood was sampled from the IVC and hepatic vein during RHC. Bile acids were quantified from serum using liquid chromatography-tandem mass spectrometry. To model hepatic congestion, mice underwent ligation of the IVC. Blood and tissue samples were harvested and underwent mass spectrometry evaluation for the bile acid composition and immunohistochemistry was performed to characterize the immune landscape, respectively.

Results:
We captured a total of 12 control samples from patients with normal filling pressures, 25 patients with left heart failure (LHF), and 23 patients with RF. Patients with RHF had poorer survival outcomes compared to control or LHF. Patients with RHF had significant increases in specific conjugated bile acids when compared to control or LHF (Figure 1).

Conclusions:
In this study, we identified several conjugated bile acids that are uniquely elevated in patients with RHF compared to LHF and control. Additionally, patients with RHF had poorer survival. Collectively, these data suggest bile acids may serve as important biomarkers and signaling molecules in the pathogenesis of cardiogenic liver disease.
Abstract Mo045: The metabolic landscape of Fontan-associated liver disease
Authors: Sule Rasheed , Hu Po , Petucci Chris , Wilkins Benjamin , Rychik Jack , Pei Liming
Published: October 2024

Introduction:
Congenital heart diseases (CHDs) are the most common birth defects in the U.S. There are growing numbers of infants and children living with single ventricle congenital heart disease (SVCHD), a unique congenital cardiac anomaly in which there is only one functional ventricle. The Fontan surgery is the current standard of care for SVCHD. Although operative survival has improved over the years, it is now evident that these surviving patients are facing new life-threatening challenges: severe complications resulting from the Fontan operation, including one of the most evident consequences-hepatic fibrosis, which is now recognized as Fontan-Associated Liver Disease (FALD). Unfortunately, the mechanisms underlying FALD remain little understood. Improved understanding in this knowledge gap will offer crucial insights into FALD pathophysiology that can lead to targeted therapies for SVCHD patients.

Goal:
To determine if liver metabolism changes significantly in FALD and compare these liver metabolomics changes to metabolic gene expression (our snRNA-ATAC-seq data) and reported plasma metabolomics results, and validate the key findings.

Methods:
We recently generated the first single-cell transcriptomic landscape of human FALD using snRNA-ATAC-seq, which revealed profound metabolic reprogramming in FALD. Here we utilized metabolomics to further understand this. Liver samples/biopsies were collected from healthy donors and FALD patients. The extracted metabolites were analyzed using C18 and HILIC HPLC/MS columns. Raw data files were acquired by high resolution MS on Orbitrap and processed by Compound Discoverer. Further statistical and bioinformatics analyses were performed to identify altered metabolites and potential metabolic pathways involved in FALD.

Results:
Significant changes of metabolite levels of multiple metabolic pathways were observed in Fontan livers, often consistent with the gene expression results. Overall, these data unveiled profound metabolic abnormalities in livers of patients with early-stage FALD.

Conclusions:
In conclusion, our investigation revealed alterations in metabolites involved in glycolysis/gluconeogenesis, mitochondrial electron transport chain, and amino acids in early-stage FALD. The observed correlations between the metabolomics and gene expression results reveal new insights into the mechanisms underlying FALD. FALD is not only a hepatic fibrosis disease, but also features severe dysregulation of liver metabolism.
Abstract Mo056: Cholinergic Activation Suppresses Optogenetic Stimulation of Intrinsic Cardiac Catecholaminergic Neurons in Perfused Mouse Hearts
Authors: Russo Rebekah , Moreno Angel , Mendelowitz David , Kay Matthew
Published: October 2024

Balance of cholinergic and catecholaminergic activation is necessary to maintain heart health. Interrogating the acute interaction of these autonomic pathways can be done using optogenetics via selective expression of channelrhodopsin (ChR2) within intrinsic cardiac neurons. We tested the hypothesis that cholinergic activation via exogenous acetylcholine (ACh) would suppress the beta-adrenergic heart rate (HR) acceleration induced by tyrosine hydroxylase (TH) neuron stimulation, with the prominence of AV block increasing with increased ACh concentration. ECGs were recorded during perfused heart studies using wild-type (WT) mice and transgenic mice that selectively expressed ChR2 in TH neurons that secrete norepinephrine (NE). HR responses were measured for WT while increasing [NE] and for TH by illuminating the right atrium (465nm, microLED) at a range duty cycles and frequencies. Duty cycles (at 5Hz) increasing from 5-50% caused proportional increases in HR however HR was unstable at duty cycles >30%. At 20% duty cycle, HR increased by 39.43±6.79% (n=6). HR increased sigmoidally at frequencies from 2.5-15Hz (with 30ms pulse width) but HR was unstable at 15Hz. At 10Hz, heart rate increased by 64.24±13.47% (n=4). When comparing HR increases for TH (n=5) and WT+NE (n=4), optogenetic activation resulted in similar maximum HRs but drastically different rise times (7.6±1.25 vs 46.43±5.01 beats/sec, respectively). HR suppression at increasing doses of ACh was measured while perfusing WT hearts with NE and photostimulating TH hearts. The addition of ACh caused beta-adrenergic HR increases to diminish, eventually reaching below baseline HR. In WT+NE animals this occurred at 400nM ACh and in TH animals this did not occur until 1800nM ACh. As ACh increased in TH animals, onset of AV block occurred sooner and more prominently. In conclusion, optogenetic activation of TH neurons caused rapid HR acceleration that was suppressed by ACh at concentrations much higher than that required to suppress acceleration during NE perfusion. AV block also occurred more rapidly during TH neuron activation as [ACh] increased, demonstrating a time-dependent effect in the interaction of cholinergic and catecholaminergic activation.
Abstract Mo060: SPEG mediates increased atrial fibrillation incidence in chronic kidney disease
Authors: Navarro Garcia Jose Alberto , Lahiri Satadru , Aguilar Yuriana , Keefe Joshua , Song Jia , Li Na , Wehrens Xander
Published: October 2024

Introduction:
Chronic kidney disease (CKD) is a major public health problem. CKD is a risk factor of cardiovascular morbidity and mortality due to the increased incidence of atrial fibrillation (AF). AF onset is known to be the consequence of cardiomyocyte intracellular calcium (Ca
2+
) mishandling where increased ryanodine receptor type 2 (RyR2) activity causes triggered activity. RyR2 activity is regulated by phosphorylation of serine 2367 (S2367) by the ‘striated muscle preferentially expressed protein’ (SPEG). Reduced RyR2 phosphorylation at S2367 increases the risk of AF. We hypothesized that changes in atrial SPEG underly the increased risk of AF in CKD patients.

Methods:
The experimental 5/6 nephrectomy model was used to mimic CKD disease in mice. AF inducibility was determined using intracardiac programmed electric stimulation. Echocardiography was used to analyze cardiac structure. RYR2 phosphorylation and SPEG levels were measured by western blotting. Intracellular Ca2+ dynamics were assessed by confocal microscopy.

Results:
CKD mice showed increased serum phosphate (14.1±1.4 vs 9.3±0.4mg/dL; p<0.01), creatinine (0.4±0.1 vs 0.8±0.3 mg/dL; p<0.001) and urea (30.5±1.1 vs 20.9±0.4 mg/dL; p<0.001). AF incidence was 4-fold higher in CKD respect sham mice (60 vs 14.2%; p<0.05). CKD mice showed longer P waves (14.3±0.4 vs 12.5±0.3; p<0.01) and greater increase of left atrial size than Sham mice (35.0±7.5 vs 13.9±4.6; p<0.05). Ejection fraction was reduced in CKD mice after 6 weeks of CKD progression (57.9±0.6 vs 61.7±0.8%; p<0.001) while no changes were observed in Sham mice. SPEG levels were decreased in atria from CKD mice compared to sham (0.64±0.11 vs 1.19±0.13; p<0.05). RyR2 phosphorylation at S2367 was reduced in CKD mice atria (0.66±0.16 vs 1.25±0.26 in sham; p=0.098). Atrial cardiomyocytes from CKD mice exhibited altered Ca
2+
handling, with decreased SERCA activity (p<0.05), increased spark-mediated diastolic Ca
2+
leak (p<0.01) and increased NCX activity (p<0.05). Finally, CKD-induced AF onset was prevented in a mice with a mutation that mimics RYR2 phosphorylation at SPEG site (S2367D mice)

Conclusion:
This study shows for the first time that SPEG levels are decreased in atria from CKD mice what induces increased RyR2 activity leading to increased AF incidence. By conserving RYR2 phosphorylation at Ser2367, CKD-induced AF was prevented. Thus, we propose SPEG as a possible therapeutic target to reduce the increased incidence of AF in CKD patients.
Abstract Mo065: An Anti-arrhythmic Action and Novel Molecular Mechanisms of Alda-1 in Holiday Heart Syndrome
Authors: Khanal Saugat , Yan Jiajie , Cao Yuanyuan , Ricchiuti Nikola , Nani Alma , Chen Wayne , Fill Michael , Bare Dan , Ai Xun
Published: October 2024

Introduction:
Holiday Heart Syndrome (HHS) is caused by excessive binge alcohol intake. Atrial fibrillation (AF) is the most common arrhythmia in HHS patients. With a worldwide rising trend in heavy alcohol consumption despite significant prevention efforts, effective drugs against alcohol-evoked AF are in urgent need.

Methods:
We assessed the effect of Alda-1, a cardiac protective agent, on mitigating binge alcohol-evoked AF and alcohol-activated stress kinase JNK2 in 50mM alcohol-exposed (24hr) H9c2 differentiated myocytes and in a well-characterized HHS mouse model (2g/kg ethanol i.p., 4 injections, every other day). Alda-1’s effect on alcohol-evoked RyR2 channel-mediated Ca
2+
waves/sparks & tachycardia/fibrillation (AT/AF) incidence were measured in intact mouse atria. RyR2 channel open probability was assessed in human RyR2 single-channel recordings.

Results:
We found that Alda-1 significantly reduced atrial arrhythmia inducibility in HHS mouse atria, as evidenced by a decreased incidence of alcohol-evoked AT/AF (0 vs. 0.21 incidences/pacing attempts/animal; n=6, 8). Alda-1 is an agonist of aldehyde dehydrogenase 2 (ALDH2; a key enzyme in alcohol detoxification), which inhibits cellular apoptosis. We found that ALDH2 was increased by 42%±6 in HHS mice compared to controls, and which remained elevated upon Alda-1 treatment (n=6,7,7; p<0.05). HHS hearts showed unchanged apoptotic signaling pathways, suggesting alternative mechanisms in AF genesis. Our lab recently revealed a critical role of activated cardiac stress kinase JNK2 in AF risk. Intriguingly, Alda-1 suppressed alcohol-activated JNK2 by 70%±13 (immunoprecipitated JNK2-specific activity; n=9,9, p<0.001) (but not JNK1, the other cardiac JNK isoform) in cells, while JNK2 inhibition alleviated alcohol-evoked RyR2 channel dysfunction in human RyR2 channels as well as Ca
2+
-triggered atrial arrhythmic activities and AT/AF (0 out of 8; p<0.05) in intact mouse hearts.

Conclusion:
Alda-1 effectively mitigates binge alcohol-evoked atrial arrhythmogenesis by suppressing JNK2 activity independently of an ALDH2-mediated anti-apoptosis effect. Our findings highlight the potential of Alda-1 as a therapeutic agent for the increasing incidence of alcohol-evoked AF.
Abstract Mo066: A Bifunctional Actuator Reverses Na
V
1.5 Dysfunction Linked To Cardiac Arrhythmias
Authors: Fossier Lucile , Yehya Marc , Mahling Ryan , Gabelli Sandra , Colecraft Henry , Ben Johny Manu
Published: October 2024

Cardiac voltage-gated sodium channels (Na
V
1.5) are critical for the initiation of action potentials within the heart. Alterations in Na
V
1.5 function significantly contribute to diverse inherited and acquired arrhythmias, such as Long QT syndrome (LQT), Brugada syndrome (BrS), mixed-syndrome, and heart failure. These pathologies are closely associated with two distinct modifications in Na
V
1.5 function: (1) a gain-of-function phenotype, characterized by incomplete inactivation of Na
V
1.5 leading to a sustained Na
+
current (
I
NaL
), and (2) a loss-of-function phenotype resulting in diminished peak Na
+
current (
I
NaP
). Despite the broad understanding of Na
V
1.5 implication in cardiac pathophysiology, the development of effective therapeutic strategies to reverse these dysfunctions remains challenging.

Here, we introduce a novel bifunctional actuator that inhibits
I
NaL
and upregulates
I
NaP
, as a common molecular strategy to reverse pathophysiological changes in Nav-linked cardiac arrhythmias. To do so, we use a genetically encoded approach by engineering a selective nanobody (nb82) targeting Na
V
1.5, linked to (1) a peptide inhibitor targeting
I
NaL
(FixR), and (2) the catalytic domain of a deubiquitinase (DUB) to enhance Na
V
1.5 membrane expression. Changes in
I
NaP
and
I
NaL
were assessed using whole-cell and multichannel electrophysiology techniques in both wild-type and channelopathic mutant channels. Our results demonstrate that NbFixR-DUB effectively reduces
I
NaL
while concurrently increasing
I
NaP
for multiple channelopathic mutations. Overall, this approach holds considerable promise for rectifying both loss-of-function and gain-of-function phenotypes in Nav channelopathies.
Abstract Mo068: The role of FGF13 in modulating gap junction protein Connexin-43
Authors: DAS LALA TANMOY , Malvezzi Mattia , Gade Aravind , Matsui Maiko , Marx Steven , Pitt Geoffrey
Published: October 2024

Background:
Fibroblast growth factor homologous factors (FHFs) are associated with arrhythmias like Brugada syndrome and atrial fibrillation, but their pathological mechanisms remain poorly understood. FHFs are best characterized as regulators of voltage gated sodium channels (VGSCs), however recent studies suggest broader, non-VGSC-related functions, including regulation of microtubules. Whether and how non-VGSC regulatory functions modulate cardiac rhythm is not known.

Hypothesis:
FGF13 regulates Cx43 trafficking and expression in ventricular cardiomyocytes via destabilizing microtubules.

Aims:
Building on an unbiased proteomic screen, we investigated if FGF13, the predominant FHF in rodent heart, affects the expression and trafficking of Connexin-43 (Cx43), the predominant gap junction protein in ventricular myocytes.

Methods:
To identify additional FGF13-dependent functional roles, we employed proximity labeling proteomics in mouse heart with the TurboID biotin ligase fused to FGF13. We used immunoblots, immunohistochemistry, and immunocytochemistry to further characterize the effects of FGF13 ablation on Cx43 pattern distribution and expression. We also leveraged electrophysiology techniques using gap junction inhibitors to detect any Cx43-dependent functional changes in FGF13-ablated cardiomyocytes.

Results:
The proteomic data revealed that cell junction proteins associated with the intercalated disc (ID) were among the top FGF13 near neighbors, of which Cx43 was heavily enriched, together with microtubule associated proteins (MAPs) known to be critical for cardiomyocyte function and ion channel trafficking. In ventricular cardiomyocytes from constitutive cardiomyocyte-restricted
Fgf13
knockout mice, we found markedly perturbed trafficking of Cx43 and reduced colocalization with the ID marker N-Cadherin. Separately, MAP4 abundance was markedly reduced. The addition of colchicine, a microtubule destabilizing drug, to WT cells altered Cx43 distribution pattern similar to that observed in FGF13-ablated cardiomyocytes. Re-expression of FGF13 restored Cx43 trafficking and ID targeting. Electrophysiology experiments using a Cx43 hemichannel inhibitor, Gap19, showed a perturbation of the action potential duration in knockout cardiomyocytes. Isoproterenol-induced action potential prolongation in knockout myocytes was decreased by the addition of Gap19.

Conclusions:
FGF13 regulates microtubule-based trafficking and targeting of Cx43.
Abstract Mo071: Engineered Platform to Uncover Cellular Cross-Talk and Arrhythmogenesis in Idiopathic Ventricular Fibrillation (IVF)
Authors: Josvai Mitchell , Reilly Louise , Anderson Corey , Walters Janay , Ni Haibo , Lawson Jodi , Stanwood Walter , Zhang Jianhua , Kamp Timothy , SACHER Frederic , Glukhov Alexey , Grandi Eleonora , Crone Wendy , Eckhardt Lee
Published: October 2024

Background:
Idiopathic VF (IVF) represents an unmet clinical need with ~50% of patients having no known monogenic cause. This has resulted in the lack of an appropriate experimental model system, limiting effective treatment through an evidence-based approach. Within IVF, several subphenotypes have emerged through Deep Phenotyping. We recruited patients with Purkinje cell premature ventricular contraction-driven IVF (PVC-IVF) to generate induced pluripotent stem cells (iPSCs).

Aim:
To characterize PVC-IVF patient-specific iPSCs using a physiologically relevant engineered
in vitro
model. We hypothesize this model will allow for mechanistic characterization of PVC-IVF.

Methods:
Patient-specific iPSC-cardiomyocytes (CMs) and iPSC-cardiac fibroblasts (CFs) were plated on 10 kPa polydimethylsiloxane (PDMS) culture platform with Matrigel in either monolayers or interconnected 40 µm lanes (
Fig. 1A
). Optical mapping was used to characterize Ca
2+
handling and action potentials. Control cells were from non-diseased persons.

Results:
CM-CF coculture results in a monolayer yet maintains the underlying organization (
Fig. 1B-C
). Patterned constructs have increased conduction velocities and anisotropy. Custom stimulation protocols were developed to probe arrhythmia susceptibility and restitution kinetics (
Fig. 1D-E
). A genetic algorithm was used to optimize a biophysically detailed CM model which enabled identification of differential model parameters between IVF and control data (
Fig. 2A-B
). These data will be used to develop a Ca
2+
handling–conduction–contractility paradigm specific to PVC-IVF as well as a mechanistic-based understanding of the disorder.

Conclusions:
Topography informs CM structure, while CFs remodel the matrix to form a monolayer, enabling full field electrophysiological definition at the cell and tissue scale. The
in vitro
model provides a unique microenvironment to determine the arrhythmogenic mechanism of PVC-IVF.
Abstract Mo072: Sustained Biological Pacemaker Activity Induced by AAV9-hTBX18
Authors: Miguel dos Santos Rodrigo , Mesquita Thassio , Sanchez Lizbeth , Li Liang , Marban Eduardo , Cingolani Eugenio
Published: October 2024

Background:
Sinoatrial node (SAN) dysfunction is a clinical disorder characterized by the inability of the SAN to maintain an appropriate heart rate (HR). Patients with this condition often need an electronic pacemaker. Although it is the current standard of care, devices can have complications. A biological pacemaker has been created by adenovirus expressing TBX18 as an alternative.

Hypothesis:
However, adenoviruses are immunogenic, limiting the duration of expression. We hypothesized that an AAV9 would promote prolonged TBX18 expression, induce somatic reprogramming
in vivo,
and sustained pacemaker activity.

Methods:
AAV9 containing GFP or TBX18 was directly injected into the myocardium of eight-week-old male Sprague Dawley rats (n=70) at low (1x10
9
GC), mid (1x10
10
GC) and high (1x10
11
GC) doses. Transient AV block was induced by tail vein injection of adenosine. A permanent complete AV block was induced by ablation of the his bundle. Hearts were harvested for optical mapping and mRNA analysis.

Results:
Six weeks after injection, all doses of AAV9-TBX18 had increased HR (low: 104±4, p=0.04; mid: 106±3.4, p=0.008; high: 103±4.1, p=0.04; vs GFP: 89±3 bpm) compared to AAV9-GFP when we induced AV block using adenosine. AAV9-GFP and -TBX18 mid dose injected rats underwent surgery to induce complete AV block. TBX18 group presented superior HR over the 24 hours monitored. 6-lead EKG analysis of the QRS axis in the frontal plane revealed that the ventricular ectopic beats from the AAV9-TBX18-injected group originated from the injection site. Activation maps further confirmed that the injection site originated those beats in TBX18-injected rats only. Successful reprogramming of adult ventricular myocytes into SAN-like cells was confirmed by transcriptional profiles with increased expression of TBX18 (2.2±0.5 FC, p<0.0001) and Hcn2 (25.2±1.1 FC, p=0.02), and reduced Gja1 (-10.8±0.7 FC, p=0.005), Scn5a (-1.1±0.8 FC, p=0.01) and Nkx2.5 (-2.0±0.6 FC, p=0.004) relative to GFP.

Conclusion:
Collectively, these data indicate that the AAV-based somatic reprogramming induced by TBX18 leads to sustained biological pacemaker activity in rats with AV block. Long-term studies are needed to characterize the long-term effects of sustained TBX18 expression.
Abstract Mo073: Elucidating the Role of Cardiac Radiotherapy on the Sympathetic Nervous System as a Treatment for Ventricular Tachycardia
Authors: Ng Sherwin , Rentschler Stacey
Published: October 2024

Ventricular tachycardia (VT) is a dangerous arrhythmia that occurs in structurally and electrically heterogenous regions of the diseased heart, leading to sudden cardiac arrest and death if left untreated. One of the main drivers underlying the arrhythmogenic substrate is abnormal remodeling of the autonomic nervous system after cardiac injury, resulting in a heterogenous distribution of sympathetic innervation and subsequent ventricular arrhythmia. In patients with VT refractory to conventional therapy, noninvasive cardiac stereotactic body radiotherapy (SBRT) has emerged as a promising new treatment. Here, we investigated whether cardiac radiotherapy homogenizes the arrhythmogenic substrate through induction of cardiac sympathetic nerve innervation and activity in a closed-chest ischemia reperfusion murine model of ischemic heart failure.

Using single nucleus-RNA sequencing, we identified global transcriptomic changes in the left ventricle 6 weeks after 25 Gray (Gy) cardiac X-ray radiation. Notably, these changes included increased expression of neurotrophins such as brain derived neurotrophic factor, a growth factor essential for neuronal survival and development, in irradiated hearts compared to sham controls. Consequently, Western blot and immunofluorescence showed increased expression of the sympathetic neuronal markers tyrosine hydroxylase and neuropeptide Y at the scar border zone of irradiated mice. Similar immunofluorescence results were observed at the irradiated border zone from the explanted heart of a patient previously targeted with 25 Gy compared to a nontargeted remote region within the same heart. These findings suggest a novel role for radiation-induced remodeling of the sympathetic nervous system in the anti-arrhythmic response to SBRT.