bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 18589: Safety and Tolerability of CSL112 in Subjects With Stable Atherothrombotic Disease: Results From a Phase 2a, Multicenter, Randomized, Double-Blind, Placebo-Controlled, Ascending-Dose Study
Authors: Tricoci Pierluigi , D’Andrea Denise M , Gurbel Paul , Cuchel Marina , Winston Brion , Schott Robert , Weiss Robert , Blazing Michael , Corteville David , Bailey Alison , Angiolillo Dominick J , Dalitz Penelope , Myles-Di Mauro Shelley , Shear Charles , Alexander John H
Published: April 2024

Purpose:
CSL112 is a novel formulation of apoA-I purified from human plasma and reconstituted to form HDL particles. Based on the ability of infused apoA-I to rapidly remove cholesterol from atherosclerotic plaque, CSL112 is being developed to reduce CV events following ACS. This phase 2a trial assessed the safety profile and pharmacokinetics (PK)/pharmacodynamics (PD) of CSL112 after a single IV infusion and is the first study of CSL112 in pts with stable atherothrombotic disease.

Methods:
45 subjects were randomized to either CSL112 (1.7, 3.4, 6.8 g) or matching placebo in a 3:1 ratio. The primary safety profile was assessed by the frequency of elevations in alanine aminotransferase (ALT) or aspartate aminotransferase (AST) (>3x ULN) and study-drug-related adverse events (AEs). PK/PD assessments included apoA-I plasma concentration and serum cholesterol efflux capacity.

Results:
Of the 45 subjects randomized, 33 received CSL112 and 11 received placebo; 1 patient (6.8 g group) did not receive study drug and was excluded from the safety analyses. Elevations (>3x ULN) in AST or ALT were not observed in any treatment group. AEs occurring within 72 h of infusion or considered drug-related by investigators were nonserious and mild except for one case of atrial fibrillation in the placebo group. AEs were reported in 5 of 7 (71.4%), 5 of 12 (41.7%), and 6 of 14 (42.9%) subjects in the CSL112 1.7, 3.4, and 6.8 g groups, respectively, compared with 3 of 11 (27.3%) subjects in the placebo group. The numeric imbalance in AEs for CSL112 groups was attributable to vessel puncture site/infusion site bruising and headache. Evaluations of mean levels and absolute change of serum creatinine over time were similar across CSL112 and placebo groups. Robust and immediate dose-related increases in baseline-corrected apoA-I AUC and Cmax were observed, resulting in similar dose-related increases in baseline-corrected total cholesterol efflux capacity.

Conclusion:
CSL112 was well tolerated and did not adversely impact hepatic or renal function in subjects with stable atherothrombotic disease. CSL112 represents a novel investigational approach to raise apoA-I levels and to reduce cholesterol content in atherosclerotic plaque. Additional clinical studies of CSL112 are warranted.
Abstract 18593: Use of a CRISPR/Cas System for Cardiovascular Disease Modeling and Therapeutic Applications
Authors: Ding Qiurong , Cowan Chad A , Musunuru Kiran
Published: April 2024

Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) systems have recently emerged as a new technology with which to perform genome editing in mammalian cells. We have tested the targeting efficiency of a CRISPR/Cas system in human pluripotent stem cells (hPSCs) by designing CRISPRs targeting eight loci in seven genes--AKT2, CELSR2, CIITA, GLUT4, LDLR, LINC00116, and SORT1. We found that different CRISPRs yield mutant clones at efficiencies of 51%-79%, with homozygous mutant clones generated at efficiencies of 7%-25%--far superior to any other genome-editing tool evaluated to date. Using this CRISPR/Cas system, we have generated isogenic cell lines with and without disease mutations, followed by differentiation into different cell types relevant to cardiovascular and metabolic diseases, including hepatocytes, adipocytes, and cardiomyocytes, which allows for rigorous human disease modeling and elucidation of new disease mechanisms. For example, using this system we have discovered that the novel gene LINC00116 has a role in lipid metabolism in adipocytes. We are building on these initial results by testing the CRISPR/Cas system for in vivo genome editing in mice, with a view towards establishing a novel therapeutic modality. We have delivered in vitro transcribed RNAs encoding Cas9 nuclease and CRISPRs targeting genes of therapeutic interest--e.g., the PCSK9 gene--formulated in lipid nanoparticles specific to mouse liver, with the intent of knocking out the gene in liver. These experiments provide a proof-of-principle that a CRISPR/Cas system could be used for human therapeutic applications in the future.
Abstract 18617: Is Genetic Hypertension Immunologically Mediated and Adoptively Transferrable by Bone Marrow From the Spontaneously Hypertensive Rat?
Authors: Singh Madhu V , Cicha Michael Z , Whiteis Carol A , Chapleau Mark W , Zavazava Nicholas , Abboud Francois M
Published: April 2024

We have recently reported that a proinflammatory state of the innate immune system may contribute to genetic hypertension in the spontaneously hypertensive rat (SHR). In these experiments we contrasted the population of immune cells from SHR and from the normotensive control WKY, and tested the hypothesis that the hematopoietic system of SHR is prohypertensive when adoptively transferred to a normotensive F1 hybrid (WKY x SHR) rat. We performed immuno-phenotyping of splenocytes from the day of birth to 38 weeks. A specific subset of CD161+ splenocytes, which was sparsely seen in WKY (<1%) at any age, was increased at birth in SHR to a level of 5% and progressively increased to 10, 20 and 30% at 5, 20, and 38 weeks of age respectively. CD161+ cells are characteristically Th17 cells, NK cells, and dendritic cells that overexpress retinoic acid related orphan receptor gamma (RORγt) and IL-17, a pro-inflammatory prohypertensive cytokine. We also transfused bone marrow from 5-week-old male WKY or SHR into 5-week-old F1 hybrid rats (WKY x SHR) that had been sub-lethally irradiated (9-12 Gy). Blood pressure (tail cuff) of the recipient F1 rats was measured after transplantation. Early results indicate that at 2, 5 and 7 weeks after transfer, the systolic pressure averaged 140±2, 152±8, and 150±5 mmHg (n=4) in F1 recipients of WKY marrow, respectively. Corresponding values in F1 recipients of SHR marrow were 150±5, 158±5, and 169±6 mm Hg (n=4). We conclude that 1) SHR exhibit a much higher abundance of proinflammatory CD161+ immune cells than WKY beginning prior to the onset of hypertension and progressively increasing with age, and 2) Preliminary results suggest that genetic hypertension may be adoptively transferred with bone marrow from SHR and not WKY rats.
Abstract 18635: Development of a Swine Model of Chronic Postcapillary Pulmonary Hypertension: Long Term Characterization by Cardiac Catheterization, Magnetic Resonance and Pathology
Authors: Pereda Daniel , García-álvarez Ana , Sanchez-Quintana Damián , Nuño-Ayala Mario , Fernández-Jiménez Rodrigo , Fernández-Friera Leticia , García-Ruiz Jose Manuel , Sandoval Elena , Castella Manel , Hajjar Roger , Fuster Valentin , Ibañez Borja
Published: April 2024

Background:
Postcapillary pulmonary hypertension (PH) has high prevalence and morbimortality. There are no large-animal models that fully reproduce postcapillary-PH. We aimed to develop and characterize a model that reproduced chronic postcapillary-PH including typical features in lungs and RV.

Methods:
Thirteen (10 banding, 3 sham) 4 week-old pigs underwent non-restrictive banding of the confluent of both inferior pulmonary veins. Chronic PH develops as the animal grows. Right heart catheterization and cardiac magnetic resonance (CMR) were performed immediately before and after the procedure and monthly thereafter during 4 months. Histopathology study of the heart and pulmonary vessels (Masson trichrome and picrosirius red staining) was performed at the end of the study.

Results:
All banded animals developed chronic PH. Compared to sham, mPAP in banded subjects was significantly higher after 1 month [median (1st-3rd quartile): 26mmHg (25-31) vs. 21mmHg (14-22), p=0.03], increased progressively and reached a plateau after month 3 [33mmHg (28-40) vs. 35mmHg (32-38) at months 3 and 4 respectively; Figure]. PVR behaved similarly and achieved significance after 2 months [5.2WU (3.8-7.1) vs. 2.3WU (2.1-3.5), p=0.03]. CMR demonstrated significant differences in indexed-RV end-systolic volume [42mL/m2 (36-53) vs. 24mL/m2 (24-33); p=0.03], indexed-RVmass [28g/m2 (27-29) vs.19g/m2 (18-23); p=0.02] and RVEF [59% (54-63) vs.66% (64-68); p=0.03] from the 2nd month and thereafter. Histopathology revealed vascular remodeling of pulmonary arteries including hypertrophy and fibrosis of the media, intimal fibrosis and RV myocardial disarray and fibrosis (Figure).

Conclusions:
We have successfully developed a large-animal model that produces chronic PH similar of that found in patients, associated with RV remodeling and typical pathology changes. The stability on PAP between months 3 and 4 makes this period the best to test therapies.
Abstract 18639: Ventricular Tachycardia Events Are Associated With Admissions for Infection or Heart failure in Patients With Left Ventricular Assist Devices and Implantable Cardio-Defibrillators
Authors: ONeill Thomas J , Katz Jason N , Waters Sarah , Bowen Amanda , Guise Kimberly , Chung Eugene , Gehi Anil , Jensen Brian C , Chang Patricia , Mounsey John P , Schwartz Jennifer
Published: April 2024

Background:
Left ventricular assist devices (LVAD) have dramatically affected the treatment of end stage heart failure (HF), however preventing readmissions remains critical to optimize patient quality of life. Following LVAD implantation, pts are readmitted most commonly for infection, HF, arrhythmia and anemia. We designed a novel implantable cardio-defibrillator (ICD) programming protocol for pts with LVADs and ICDs to maximize ventricular arrhythmias (VA) detection and minimize shocks. We hypothesized that increasing detection of VA in LVAD pts may reduce readmission rates.

Methods:
Forty-two pts at UNC with an LVAD and ICD underwent reprogramming. The protocol included: ventricular fibrillation >220 bpm; ventricular tachycardia (VT) >185 bpm with 12 bursts of ATP then a single shock; VT monitor >150 bpm. Device interrogations were performed at LVAD clinic follow up, for symptoms, and at the time of readmission. Data was collected with an approved institutional IRB.

Results:
During an average follow up of 11.3 months before and 7.4 months after reprogramming, there were 53 unplanned admissions (21 admissions after ICD reprogramming). After reprogramming 5 admissions (23% - 1438 patient-days/admit) were for HF or VA. Prior to reprogramming there were 15 HF/VA admissions (728 patient-days/admit). After reprogramming 4 admissions (18%) were for bacterial infections (5 prior to reprogramming). The remaining were primarily for anemia (17%) or neurologic symptoms (36%). After reprogramming, arrhythmias were detected on ICD interrogation in 3 of 5 HF and 2 of 4 bacterial infection admissions. 40% were due to sustained VA >10 sec and 60% were due to supraventricular tachycardia. By comparison 0/13 of the other admissions had documented ICD arrhythmias.

Conclusions:
Following implementation of a novel ICD programming protocol to increase detection of VA, there was a marked decrease in admissions for cardiac diagnoses. ICD interrogations found VA events were associated with admissions for HF and infection. HF and infections may cause hemodynamic perturbations that result in arrhythmias detected by ICDs with appropriate programming. Our data suggests that ICD data may augment available techniques to assess and triage this patient population.
Abstract 18672: Effects of Prolonged Space Flight on Cardiac Structure and Function
Authors: Abdullah Shuaib M , Hastings Jeffrey L , Shibata Shigeki , Platts Steven H , Hamilton Douglas R , Thomas James D , Hughes Douglas E , Bungo Michael W , Levine Benjamin D
Published: April 2024

Background:
“Cardiovascular deconditioning” induced by bed rest, a model for spaceflight, causes cardiac atrophy of ~1%/wk in men and women. Data from small numbers of astronauts NOT performing any exercise countermeasures suggest the rate of atrophy for spaceflight may be even greater. However, cardiac morphology has not been assessed using high resolution techniques before and after prolonged space flight in the International Space Station (ISS) era.

Methods:
Cardiac magnetic resonance imaging (MRI) to assess left and right ventricular volumes and masses, and fibrosis by late gadolinium enhancement was performed within 2 months before and 3 days after 4-6 months in space aboard the ISS on 13 astronauts.

Results:
Eight men and 5 women (mean age 49.5 years) astronauts participated (mean ISS duration 153 days). All performed regular and intensive combined endurance and strength training countermeasures inflight, and most did so at a higher intensity than they did pre-flight. No significant differences in left ventricular or right ventricular end-diastolic and -systolic volumes were observed (Table). Both right and left ventricular mass was preserved, and supine stroke volume was maintained. No evidence of myocardial fibrosis was seen in 11 astronauts who had late gadolinium enhancement performed before and after space flight.

Conclusions:
No deleterious effects of prolonged space flight were seen on cardiac structure and function. These results suggest that an appropriate astronaut exercise regimen may counteract the effects of “cardiovascular deconditioning” during prolonged space flight up to 6 months duration.
Abstract 18697: Utilization of Atrial Flutter Ablation and its Complications - Analysis of 38000 Procedures
Authors: Savani Ghanshyambhai T , Pant Sadip , Bhalara Vipulkumar , Chothani Ankit , Patel Nileshkumar J , Shah Neeraj , Mehta Kathan , Grover Peeyush , Singh Vikas , Pothineni Naga Venkata K , Deshmukh Abhishek , Khalpada Dhaval , Rodriguez Alexis , Badheka Apurva O , Mitrani Raul D , Paydak Hakan
Published: April 2024

Introduction:
Radiofrequency ablation (RFA) of atrial flutter (AFL) is considered as a reasonable approach due to its effectiveness, feasibility and safety. Data regarding the utilization and safety of RFA for AFL outside of selected centers of excellence and in older patients are limited.

Methods:
Using the Nationwide Inpatient Sample (NIS) between the years 2000-2008, we developed a coding algorithm to identify AFL patients treated with ablations. We investigated common complications like cardiac perforation and/or tamponade, pneumothorax, stroke, transient ischemic attack (TIA), vascular access complication (consisting of hemorrhage/hematoma, vascular complication requiring surgical repair, and accidental puncture), and in-hospital death described with AFL ablation and defined them by validated International Classification of Diseases (9th Edition) Clinical Modification (ICD-9-CM) diagnosis codes.

Results:
There were a total of 38,881 AFL ablations performed from the years 2000 to 2008. Majority of ablations were performed in patients with age > 65 years, men, white race, less severe comorbidities, large bed size and teaching hospitals. The overall inhospital mortality was 15/1000. The overall complication rate was 0.3%. On multivariate analysis, apart from male gender, patient and hospital characteristics were not associated with increased complications. The length of stay and total charges were 1.5 and 2.5 times more in hospitalizations associated with complications.

Conclusions:
AFL ablation is safe with perforation/tamponade and vascular access complications accounting for the majority
Abstract 18736: Relationship of PCSK9 With Measures of Vascular Disease and Global Risk in 1574 Individuals Enrolled in the FATE (Fireman And Their Endothelium) Study
Authors: Verma Subodh , Lonn Eva M , Fung Marinda , Anderson Todd J
Published: April 2024

Background:
Proprotein convertase subtilisin kexin-like 9 (PCSK9) is a secreted glycoprotein that is transcriptionally regulated by cholesterol status. Elevated PCSK9 levels lead to an increase in circulating LDL-C by inhibiting hepatic LDL-receptor recycling by targeting LDL-receptors for lysosomal degradataion. Since loss-of-function PCSK9 variants are associated with marked cardiovascular protection, we hypothesized that plasma PCSK9 levels may serve as a biomarker of structural and functional atherosclerosis, and would add prognostic value beyond conventional global risk scores.

Methods:
The FATE cohort consisted of 1574 men (mean age, 49.4 years) free of vascular disease. Measurements included flow-mediated dilation (FMD) and its microvascular stimulus, hyperemic velocity (VTI), carotid intima-media thickness (CIMT), and high-sensitivity C-reactive protein (hs-CRP). Plasma PCSK9 was measured using a quantitative sandwich immunoassay technique, using a monoclonal antibody specific to PCSK9. Cox proportional hazard models evaluated the relationship between PCSK9, vascular markers, and Framingham risk score (FRS).

Results:
Subjects had low-medium Framingham risk score (7.9%), with mean LDL-C (3.3±0.8 mM), HDL-C (1.2±0.3 mM), and hs-CRP mg/L 1.27 (0.67-2.27). Mean brachial artery FMD was 8.6±4.1%, nitroglycerin-mediated dilatation was 15.6±5.8% and CIMT 0.70 (0.6-0.77) mm. Plasma PCSK9 was normally distributed (median 286 ng/ml [231-355 ng/ml]). In univariate analysis, both PCSK9 and logPCSK9 were related to CIMT (pearson coefficient 0.073, p<0.005), but not to VTI (pearson coefficient -0.041, p=NS) or hs-CRP(pearson coefficient 0.003, p=NS). In multiple linear regression analysis, FRS was independently associated with both CIMT and VTI (both p<0.001). However, PCSK9 was not associated with either CIMT or VTI beyond FRS.

Conclusion:
In a large cohort of 1574 otherwise healthy individuals, plasma PCSK9 levels were not related to measures of either microvascular or macrovascular dysfunction beyond the FRS score. Whether PCSK9 predicts cardiovascular events remains to be determined.
Abstract 18737: Prevalence and Outcome of Patients With Idiopathic QT Prolongation Identified Through an Institution-Wide QT-Alert System
Authors: Bos Johan M , Haugaa Kristina H , Tarrell Robert F , Morlan Bruce W , Caraballo Pedro J , Ackerman Michael J
Published: April 2024

Background:
Since QT prolongation is a risk factor for sudden death, stroke, and all-cause mortality, we developed an electronic, institution-wide QT alert system to identify patients with significant QT prolongation (i.e. QTc≥500 ms if QRS <120 ms). These patients encountered a significant increased mortality within 1 year, and nearly 40% of patients with ≥4 QTc inciting factors have died. Herein, we examined the patients with ≤1 identifiable QTc inciting factor.

Methods:
Between November 2010 and June 2011, 53,732 patients underwent ECG-evaluation, 1,145 QT-alerts (2.1%) were triggered, and 470 of the QT-alerted patients had ECG-isolated QT prolongation. Clinical, laboratory, and therapeutic information were collected. Excluding female gender and bradycardia, other potential QT inciting factors (drugs, electrolyte disturbances, and co-morbidities) were synthesized into a pro-QT score and patients with a score of ≤1 were compared to patients with a pro-QT score >1.

Results:
About one-third (N=150, 59% female) of this QT-alerted cohort had a pro-QT score of ≤1 including 42 patients with an established diagnosis of congenital long QT syndrome (LQTS). Excluding LQTS patients, the remaining 108 patients (60 female, age 59±25 years) were significantly more likely to have a QT prolonging cardiovascular co-morbidity (44%) than those with a QT-score >1 (29%; p=0.006). However, mortality was similar between those with a QT-score ≤1 (19%) and those with a QT-score >1 (27%, p=0.09). Fourteen patients (9 female; age 64±22 years; QTc 507±14 ms) had no discernible QT inciting factors (i.e. pro-QT score=0) including 6 patients with previously documented QT prolongation.

Conclusions:
Only a minority of patients with ECG-isolated QT-prolongation (~3%) had no discernible QT-inciting factors other than female gender in 9. Careful scrutiny of these patients with seemingly idiopathic QT prolongation may identify novel QT provoking conditions. Alternatively, considering that 14 of 53,732 patients (1 in 3888) activated the alert system without obvious QT inciting factors and that congenital LQTS has an estimated prevalence of 1 in 2000, it is possible that this universal QT alert system has caught patients with yet to be diagnosed LQTS.
Abstract 18740: Cardiac Magnetic Resonance Evaluation of Coronary Anatomy and Myocardial Viability After Arterial Switch Operation
Authors: Adebo Dilachew , Whitehead Kevin , Fogel Mark , Harris Matthew
Published: April 2024

Background:
Arterial Switch Operation (ASO) is the treatment of choice for anatomic correction of transposition of the great arteries (TGA). One of the major concerns after ASO is the evaluation of the translocated coronary arteries. There are limited studies evaluating the role of cardiac magnetic resonance (CMR) in the follow up of patients after ASO. The purpose of this study is to evaluate the extensive use of CMR for delineating coronary artery anatomy and myocardial viability after ASO.

METHODS:
Retrospective review of 69 consecutive CMR Whole Heart T2 Prep coronary angiography studies of patients who underwent ASO for TGA. The subjects had CMR from July 2005 to December 2012. Results of inversion recovery viability imaging were also reviewed.

RESULTS:
The median age at the time of CMR was 15 years with range of 1 year to 24 years); 44 male and 25 female subjects. The coronary origins and proximal coronary arteries were well demonstrated by CMR in 97% (67/69) of the cases Among these, 70% (47/67) of the cases had typical coronary pattern for TGA after ASO while 30% (20/67) had an atypical pattern. Circumflex coronary artery arising from right coronary artery was seen in 60% (12/20) and single coronary artery originating from right or left facing sinus was identified in 40% (8/20) of the subjects with atypical coronary pattern. One patient had evidence of left circumflex coronary artery occlusion with inferior and lateral myocardial fibrosis on late gadolinium enhancement imaging. In this patient, the right coronary artery originates from right facing sinus and the left coronary artery originates from left facing sinus. The two patients with unsatisfactory image quality had dental brace artifact affecting image quality.

Conclusions:
CMR coronary angiography and myocardial viability can reliably delineate coronary anatomy and identify myocardial fibrosis after ASO for TGA.

Keywords:
Arterial switch operation; Cardiovascular magnetic resonance imaging; Transposition of great arteries
Abstract 18745: Outcomes of Mechanical Circulatory Support for Patients With Functionally Single-Ventricle Physiology at Different Stages of Surgical Palliation
Authors: Saedi Arezou , Chetan Devin , Kotani Yasuhiro , Liyanage Nishanthi , Zhao Lisa , Caldarone Christopher , Van Arsdell Glen , Honjo Osami
Published: April 2024

Introduction:
Mechanical circulatory support (MCS) for functionally single ventricle (SV) physiology poses significant challenges. We sought to analyze the results of MCS at 4 different stages of the surgical palliation process.

Methods:
From 2003 to 2013, 86 SV patients required MCS: Group 1, before any surgical palliation (n=13, 15%), Group 2, between stage I and II (n=59, 69%), Group 3, between stage II and Fontan (n=10, 12%), Group 4, after Fontan (n=4, 5%). Indications for MCS included failure to wean from cardiopulmonary bypass in 6 (7%) patients, circulatory failure in 7 (8%), respiratory failure in 9 (10%), cardiopulmonary failure in 4 (5%), and cardiac arrest in 58 (67%). Kaplan-Meier analysis was used to compare freedom from death and freedom from failure to wean between groups. Cox analysis was used to determine risk factors.

Results:
The median MCS duration was 3 days (IQR, 1-6). Of 86 patients, 58 (67%) were successfully weaned: 32 (37%) patients recovered, 8 (9%) were transplanted, 12 (14%) had operation/reoperation, and 1 (1%) had conversion to a different form of MCS. Fifty-two (60%) patients had complications including bleeding in 20, thromboembolism in 9, sepsis in 12, neurologic injury in 6, and multi-organ failure in 5. Thirteen patients required a second run of MCS. Freedom from death at 6 months after MCS initiation was comparable between the groups (Group 1, 23%, Group 2, 33%, Group 3, 15%, Group 4, 50%, p=0.66; Figure 1). Failure to wean from MCS was also comparable among the groups (p=0.46). Cox analysis revealed MCS-related complications as a risk factor for death (p=0.006) and longer duration of arrest as a risk factor for inability to wean from ECMO (p=0.036). The timing of MCS was not a risk factor for poor outcomes.

Conclusions:
Two thirds of SV patients who required MCS were rescued, although subsequent survival is generally poor across all stages of palliation. Given the poor outcomes in this cohort, consideration of alternative strategies is warranted.
Abstract 18754: The Variants of Uncertain Significance Issue on Steroids: Determination of the Background Genetic Noise Rate Within the Known Channelopathy/Cardiomyopathy-Susceptibility Genes
Authors: Kapplinger Jamie D , Ackerman Michael J
Published: April 2024

Background:
Next-Generation Sequencing (NGS) allows for sequencing of a many genes simultaneously, leading genetic testing companies to provide sequencing of all genes associated with a particular disease in large gene test panels. For example, there are over 90 distinct genes associated with premature sudden arrhythmic death. Previous publiclations have shown a background rate of rare non-synonymous single nucleotide variants (nsSNVs) in many of these genes which may be compounded when included in large gene panels. Therefore, we hoped to determine this background rate of nsSNVs in 93 genes that comprise various sudden death genetic heart disease genetic test panels.

Methods:
The exomes from the 1000 Genomes Project (1kG) and the NHLBI Exome Sequencing Project (ESP) were genotyped in-silico for nsSNVs in 93 genes indentified on clinically available genetic tests available for HCM, DCM, ARVC, LQTS, SQTS, BrS, and CPVT. The number of subjects hosting an exceedingly rare and unique nsSNV was determined for each gene.

Results:
Strikingly, 40.8% of the 1 kG cohort (12.5% hosted > 2 unique nsSNVs) and 41.9% of the ESP cohort possessed > 1 rare nsSNV within the entire 93 gene panel, while the yield of rare nsSNVs in individual genes only ranged from 0.02% for PLN to 2.3% for DMD. This background rate directly correlated with the number of genes on the panel (r=0.97). When limited to only those genes that account for >10% of the disease (HCM - MYBPC3, MYH7; LQTS - KCNQ1, KCNH2; ARVC - PKP2, DSG2; CPVT - RYR2; BrS - SCN5A), at least 7% of the subjects in both cohorts had at least one nsSNV. Thus, nearly 90% of the background rate is contained within the minor disease-susceptibility genes.

Conclusions:
Despite not being enriched for the presence of genetic channelopathies and cardiomyopathies, two out of every 5 subjects within these cohorts hosted at least 1 ultra-rare nsSNV within the 93 known channelopathy/cardiomyopathy-susceptibility genes. Despite the anticipated transition from disease-specific genetic testing to whole exome genetic testing, great caution must be exercised to glean the true pathogenic mutation amidst this very daunting burden of background genetic noise. If handled poorly, false positive genetic test results and misguided cascade screens will increase.
Abstract 18773: Discovery and Translation of Novel Long Intergenic Non-Coding RNAs in Inflammatory Cardio-Metabolic Disorders
Authors: Zhang Xuan , Ferguson Jane F , Xue Chenyi , Liu Yichuan , Hinkle Christine , Li Mingyao , Reilly Muredach
Published: April 2024

Objective:
The purpose of this study is to identify long intergenic non-coding RNAs (LincRNAs) modulated by inflammation utilizing human experimental endotoxemia and to explore their association with cardiometabolic traits.

Methods and results:
We performed deep high-throughput RNAseq (~500 million reads per sample) in adipose tissue and whole blood of a healthy subject before and after endotoxin (LPS 1 ng/Kg) administration. Of 8,179 LincRNAs identified by Cabili et al (Gene & Development 2011. 25:1915-1927), we detected 514 present in adipose and 266 in blood, with 69 (13.6%) and 56 (21.2%) LincRNAs respectively modulated by LPS with just six LPS-modulated lincRNAs overlapping in both tissues. In both tissues, LincRNAs had lower expression and more tissue specificity than protein coding RNAs. RNAseq of adipose and blood in 2 additional individuals during endotoxemia was used to confirm findings and qPCR used to validate top findings in an additional 7 study participants. Linc-ARFIP1-4 and Linc-CMC1-2 were consistently reduced by LPS in blood, but not in adipose. Interestingly, Linc-DMRT2 and Linc-TP53I13, the top adipose LPS-modulated LincRNA, was more abundant in human primary adipocytes than monocyte and macrophage cultured in vitro while adipose samples obtained from obese subjects exhibited lower Linc-DMRT2 and Linc-TP63I13 expression (77% and 50% lower respectively, P<0.05) compared to lean individuals (N=10/group). To further investigate biological roles, we generated lentiviral-vectors with short hairpin RNAs (shRNAs) targeting Linc-DMRT2 and Linc-TP53I13 as well as Linc-AQPEP, the top expressed adipose-specific LincRNA. Preliminary studies demonstrated more than 50% knockdown of these lincRNAs in human adipocytes with shRNA application and functional studies are ongoing to characterize their impact on adipocyte differentiation, lipid storage and insulin sensitivity.

Conclusion:
These novel data from a human endotoxemia experiment suggest that inflammatory modulation of adipose LincRNAs might modulate adipose functions in cardio-metabolic disorders.
Abstract 18780: Diminished Left Ventricular Myocardial Oxygen Demand During Dobutamine Stress Testing in the Elderly Reduces the Appearance of Inducible Wall Motion Abnormalities Indicative of Ischemia
Authors: Vasu Sujethra , Morgan Timothy , Kitzman Dalane W , Hamilton Craig A , Chiles Caroline , Soots Sandra , Thohan Vinay , Hundley W. Gregory
Published: April 2024

Background:
It has been observed that dobutamine stress may be less sensitive in the elderly and in those with LVH. We hypothesized that, in the elderly, a reduced increment in myocardial oxygen demand with dobutamine produces false negative results.

Methods:
We prospectively performed dobutamine cardiovascular magnetic resonance (DCMR) on 276 consecutively recruited individuals aged 55-85 years with risk factors for CAD. Rate pressure product (RPP), assessment of LV wall motion and volumes, aortic pulse wave velocity (PWV a measure of aortic stiffness) and first pass gadolinium enhanced LV perfusion defects (PD) indicative of ischemia were obtained on a 1.5T scanner at rest and after dobutamine infused to achieve 80% of the maximum predicted heart rate. Myocardial oxygen demand was assessed by the systolic pressure volume area (PVA), measured as LV stroke work (SW), [mean arterial pressure * stroke volume] plus potential energy [(1/2*end-systolic pressure) * end-systolic volume]}. All measures were assessed independently by personnel blinded to other data or participant identifiers. Differences were assessed with t-test; p < 0.05 was significant. DCMR PD was considered as the gold standard for the detection of ischemia.

Results:
Participants averaged 68±8 years, were 80% white, 90% hypertensive, 43% diabetic and 55% men; all achieved target heart rate. With dobutamine, RPP increased 85% and LV end-diastolic volume index decreased. No subject had an inducible WMA without concomitant PD, but 28 had PD without inducible WMA (Table). In these false negatives, PVA was significantly lower (p= 0.03) and LVSW (p = 0.06) and PWV (p= 0.13) had strong trends toward being lower. The sensitivity of DCMR WMA for identifying PD indicative of ischemia was 33%.

Conclusion:
With dobutamine stress testing, the elderly had declines in LV preload and PVA. These findings provide a novel mechanistic explanation of why the elderly may have false negative wall motion during dobutamine stress.
Abstract 18782: Knockout of Type VI Collagen Preserves Mitochondrial Structure and Function Following Myocardial Infarction
Authors: Meszaros J G , Luther Daniel J , Andrei Spencer R , Cappelli Holly C , Adapala Ravi K , Thoppil Roslin J , Patel Hemal , Niesman Ingrid R , Kang Patrick T , Bonaldo Paolo , Chen Yong-Renn , Thodeti Charles K , Chilian William M
Published: April 2024

Cardiac remodeling is a dynamic process that is accelerated after myocardial infarction (MI). Types I and III collagen, both fibrillar collagens, have been the focus of the remodeling and repair literature. We have recently uncovered a potentially novel role for non-fibrillar type VI collagen (Col6) in post-MI repair and global LV function. We reported that Col6 null (Col6-/-) mice are protected from ischemic injury as evidenced by significantly reduced infarct sizes and preserved systolic function. Interestingly, the Col6-/- mouse, originally developed as a model for a skeletal muscle dystrophy known as Bethlem Myopathy, allowed for the discovery that type VI collagen mutations or knockout led to mitochondrial dysfunction and skeletal myocyte apoptosis with aging. Our hypothesis that altered mitochondrial structure and function in the myocardium of Col6-/- mice is the mechanistic basis of the paradoxical protection from ischemic injury. To investigate the potential mitochondrial mechanism(s) responsible for the cardioprotection in Col6-/- mice, we began by using transmission electron microscopy (TEM) to assess mitochondrial morphology. Mitochondria from uninjured Col6-/- LV tissue had similar morphology as WT. Mitochondrial morphology at 3 days post-MI indicates that WT and Col6-/- mitochondria are compromised. However, TEMs of Col6-/- hearts 14 days post-MI show longer chains of intrerfibrillar mitochondria, whereas swollen, isolated mitochondria were apparent in WT. Interestingly, we observed a 3.0 vs. 1.7-fold increase (WT vs. and Col6-/- mice, respectively) in the fission protein Drp1 specifically in the infarcted zones at 24 hours post injury. We next measured O2 consumption 24 hours post-MI using isolated mitochondria from both phenotypes, discovering a reduced coupling of oxidative phosphorylation (44.5 ± 4.7% reduction in respiratory control index; RCI) in Col6-/- mice compared to WT controls. However, the RCI of the infarcted region in Col6-/- 24 hours post-MI hearts did not significantly decline compared to WT. Together, these data indicate that Col6-/- mice have preserved mitochondrial morphology and respiration following MI and may be a mechanism underlying the unexpected cardioprotection from MI injury in Col6-/- mice.
Abstract 18807: Novel Protein Glycan Derived Biomarker is Associated With Incident Diabetes
Authors: Akinkuolie Akintunde O , Pradhan Aruna D , Ridker Paul M , Mora Samia
Published: April 2024

Background:
Enzymatically glycosylated proteins partake in multiple cellular processes, including glucose transport and inflammation. In addition, most inflammatory proteins are enzymatically glycosylated. GlycA is a novel nuclear magnetic resonance (NMR) biomarker whose signal originates from the N-acetyl groups of N-acetylglucosmine and N-acetylgalatosamine moieties of protein glycans. We hypothesized that GlycA is directly related to the risk of incident diabetes, possibly mediated by inflammation as assessed by high-sensitivity C-reactive protein (hsCRP), a well-established inflammatory biomarker.

Method:
Baseline GlycA was quantified by NMR spectroscopy (LipoScience, NC) in 26,539 Women’s Health Study participants free of diabetes at enrollment (median follow-up 16 years; 1,990 incident diabetes cases). Multivariable Cox regression models were adjusted for age, race, treatment assignment, smoking, menopausal status, hormone use, family history of diabetes, and BMI.

Result:
GlycA correlated with hemoglobin A1c (Spearman r=0.21), HDL cholesterol (r= -0.21), triglycerides (r=0.46), BMI (r=0.40), and hsCRP (r=0.61), all p< 0.0001. Multivariable-adjusted HRs (95% CIs) for incident diabetes across increasing quartiles of GlycA were 1.00, 1.44 (1.20-1.73), 1.93(1.63-2.29) and 2.74 (2.32-3.24), p-trend<0.0001. This was attenuated but remained significant after additionally adjusting for lipids (p-trend <0.0001). Additional adjustment for hsCRP further attenuated the association (p-trend=0.02; Table).

Conclusion:
In this population of 26,539 women followed for 16 years, baseline GlycA levels were directly associated with the risk of incident diabetes independent of traditional risk factors. The association of GlycA with diabetes was attenuated after further adjusting for hsCRP, suggesting a novel role for protein glycans in the development of diabetes possibly mediated through subclinical inflammation.
Abstract 18809: PER977: A Synthetic Small Molecule Which Reverses Over-Dosage and Bleeding by the New Oral Anticoagulants
Authors: Bakhru Sasha , Laulicht Bryan , Jiang Xuan , Chen Lirong , Pan Deng , Grosso Michael , Morishima Yoshiyuki , Brown Karen , Masumoto Hiroshi , Costin James , Steiner Solomon
Published: April 2024

With regards to route of administration, drug interactions and predictability of bioactivity, the new oral anticoagulants (NOACs; direct factor Xa and IIa inhibitors) offer significant advantages over heparins and warfarin therapies. However, concern over serious bleeding, emergency procedures and potential over-dosage is heightened with the current lack of a specific reversal agent. PER977 is a synthetic small molecule rationally designed anticoagulant antidote. Reversal of anticoagulation induced bleeding was demonstrated in a rat tail transection model: weight-matched rats were overdosed with rivaroxaban, edoxaban, dabigatran, or apixaban, resulting in large increases in blood loss volume. PER977 was administered IV and after thirty minutes, blood loss volume was quantified. PER977 significantly decreased bleeding in vivo in rats treated with NOAC (Figure 1a). PT (for edoxaban, rivaroxaban, and apixaban) or aPTT (for dabigatran) and thromboelastography (TEG) (TEG- for edoxaban, Figure 1b) were also used to quantify NOAC anticoagulation reversal in vivo in rats; PER977 restored these laboratory values to baseline levels within 20 minutes of administration. Importantly, PER977 has also shown no pro-coagulant properties as measured by TEG, PT and aPTT in rat and human whole blood, nor any interaction with circulating coagulation factor proteins. In vivo and in vitro toxicology and safety studies have been completed and a first-in-human clinical trial to demonstrate safety and efficacy in healthy human volunteers with PER977 and edoxaban is underway. In conclusion, PER977 is a synthetic small molecule new chemical entity under development that reverses NOAC anti-coagulation in vivo as measured by TEG, PT, and aPTT, and also by bleeding volume in a rat tail transection model.
Abstract 18901: Metabolic Regulation of Adipose Tissue Inflammation and Systemic Insulin Sensitivity: A Role for PFKFB3 in Macrophage Polarization
Authors: Xu Hang , Guo Xin , Li Honggui , Woo Shih-Lung , Wu Chaodong
Published: April 2024

Much evidence demonstrates that macrophages play a pivotal role in the development of overnutrition-associated metabolic diseases, such as cardiovascular disease and type II diabetes. Macrophage inflammatory status (polarization) is a key determinant of systemic insulin resistance, which is under the control of bi-directional regulation: macrophage proinflammatory activation and macrophage alternative activation (anti-inflammatory). It has been previously shown that PFKFB3, a gene that encodes for a key regulatory enzyme of glycolysis, is crucial for the control of systemic insulin sensitivity. In the present study, if and how PFKFB3 alters macrophage polarization in relation to adipose tissue inflammation and systemic insulin sensitivity were examined. Bone marrow cells were isolated from wild-type mice and PFKFB3-disrupted mice and differentiated into macrophages which were referred to as bone marrow-derived macrophages (BMDM). Compared with control cells, the phosphorylation of NF-kB p65 and JNK1/2 is in PFKFB3-disrupted BMDM. Additionally, the expression of proinflammatory cytokines, such as TNF-α and IL-6, was increased in PFKFB3-disrupted BMDM under the stimulation of lipopolysaccharides (LPS, 100 ng/ml). Upon adoptive transfer of bone marrow cells to lethally irradiated wild-type mice, the recipients with PFKFB3-disrupted bone marrow cells displayed a decrease in systemic insulin sensitivity, which was accompanied by an increase in adipose tissue inflammatory responses. The later were evidenced by increases in adipose tissue macrophage infiltration, the phosphorylation of NF-kB p65, and mRNA levels of proinflammatory cytokines. Taken together, PFKFB3 is a metabolic regulator of macrophage polarization, which accounts for the effects of PFKFB3 on protecting against diet-induced adipose tissue inflammation and systemic insulin resistance.
Abstract 18905: Myocyte-Specific Deletion of P300 Prevents Cardiac Hypertrophy Following Pressure Overload in a Mouse Model
Authors: Wei Jianqin , Joshi Shaurya , Liu Jing , Hoosien Michael , Jain Sumit , Bishopric Nanette H
Published: April 2024

Background:
The lysine acetyltransferases CREB binding protein (CBP, KAT3A) and p300 (KAT3B) are important epigenetic regulators of gene transcription. Both share extensive sequence homology and multiple overlapping functions and properties. However, genetic loss-of-function studies indicate that CBP and p300 have distinct roles in cardiac development. We have previously shown that p300 is a stress-responsive, quantitatively limiting driver of cardiac hypertrophy.

Objective:
To compare the roles of p300 and CBP in adult cardiac hypertrophy.

Methods:
Recombination was induced in mice harboring the a-MHC Mer-Cre-Mer transgene and CBP or p300 floxed alleles with tamoxifen (TA) at 10 weeks of age. Pressure overload was induced by transverse aortic coarctation (TAC) and pressure gradients were quantitated by Doppler flow/velocity. Cardiac function was evaluated using echocardiography before and after surgery. Apoptosis and fibrosis was assessed using CardioTACs assay and Masson tri-chrome staining respectively. Myocyte hypertrophy and fibrosis were quantitated by histology at d21 post TAC. Genome-wide transcriptional analysis was performed by microarray and RNASeq.

Results:
TAC produced myocyte hypertrophy, cardiac enlargement, and systolic dysfunction that was reduced to near sham-operated levels in a gene-dose-dependent manner by loss of p300 (p<0.001 for p300 fl/fl vs p300+/+). Loss of p300 did not impair survival post TAC. Histologically, fibrosis and myocyte apoptosis after TAC were markedly decreased in p300fl/fl vs p300+/+ mice (15.04% vs 38.92%,p<0.001). Remarkably, cardiac systolic function (EF % and FS %) were unimpaired in p300KO mice following TAC. Loss of CBP had no impact on any of these parameters. Transcriptional analysis revealed that loss of CBP had a much greater impact on gene expression than loss of p300, and that relatively few genes were responsive to both p300 and CBP loss. A group of 89 mRNAs and ncRNAs were exclusively sensitive to p300 loss, reflecting an important function in oxidative stress.

Conclusions:
Cardiac myocyte p300 plays a critical and cell-autonomous role in cardiac hypertrophy and heart failure that is not complemented by CBP. Investigation of p300 specific gene targets is warranted.
Abstract 18907: Genetic Ablation of Voltage-Gated Potassium Channel β-subunit 2 Causes Distinct Physiological and Cardiac Alterations in Mice
Authors: Panguluri Siva K , Kilfoil Peter J , Chapalamadugu Kalyan C , Tur Jared , Bhatnagar Aruni , Tipparaju Srinivas M
Published: April 2024

Voltage-gated potassium channels (Kv) are important for cardiac function. Recent studies from our group showed dysregulation of Kv4.2 and 1.4 in diabetes or hyperoxia. The activity of Kvα is regulated by β-subunits and mutations in these subunits are associated with cardiovascular diseases. Recent report suggests that Kvβ2 (Kcnab2), a dominant β-subunit in the brain modulates inactivation rates of Kv1.4 currents and can promote the trafficking of Kv1.1 and 1.2 to the cell surface. The physiological and molecular roles of Kvβ2 in cardiac functioning are unknown. Therefore, in the current study we investigated the functional alterations and assessed the molecular changes in Kvβ2KO (KO) mouse hearts. Physical assessment of heart reveals significant cardiac atrophy in KO by measure of heart weight to tibia length ratio, WT: 7.44±0.31mg/mm vs KO: 6.23±0.15mg/mm (p<0.002). The shape and structure of KO mouse hearts are smaller than their littermate wild type (WT). Molecular evaluation shows significant (p≤0.05) elevation of atrophy markers such as pyruvate dehydrogenase lipoamide kinase isozyme 4, uncoupling protein 3, atrogin, insulin-like growth factor, phospholamban, calcineurin, and slow-twitch myosin heavy chain-7. Echocardiography showed significant reduction in end diastolic volume (EDV) in KO mice compared with WT (15% less in KO than WT, p<0.01). Action potentials recorded at room temperature from right ventricular myocytes showed that KO (n=18) had significantly slower action potential durations than WT (n=27) at APD20 (2.04±0.08ms vs. 1.78±0.06ms, p<0.025), APD50 (4.45±0.34ms vs. 3.64±0.24ms, p<0.05), and APD90 (24.30±2.56ms vs. 17.42±1.22ms, p=0.01) levels. Lead II ECG recordings from anesthetized WT and KO mice were unchanged. Western blotting revealed a significant elevation of Kvβ1.2 in right ventricle and Kv1.5 in left ventricle of KO hearts. Based on functional and pathological assessment the extent of atrophy in KO hearts along with biochemical and molecular mechanisms are reported for the first time in this study. In summary our study showed that genetic deletion of Kvβ2 cause distinct physiological and cardiac changes suggesting its importance in cardiac physiology.