bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 431: The Capillaries in Ischemic Border Zone: Origin And Role in Myocardial Infarction and Heart Failure
Authors: Chen Jiqiu , Liang Lifan , Hajjar Roger J
Published: October 2019

It is a general believe that a blocked artery and its capillary are the main factor to determine myocardial infarction (MI) size and cardiac dysfunction. We have be plagued by the problem in repairing and regeneration of MI for many decades. How to improve the infarcted myocardium? By relieving the obstruction in coronary artery or promoting the angiogenesis of capillaries in the ischemic border zone? How to regrow the deteriorated capillary? From where? It is incredible to image the role of nearby non-ligated vessels in myocardial death and cardiac depression. In the present study, we show evidences that ischemic MI are not determined solely by the occluded artery, but also involved the nearby non-occluded artery, especially its capillaries that contributed nearly one-third effort to the MI. The mechanism is unclear yet, but this phenomenon is very interesting, offers a novel perspective to study heart failure. Arterial resistance to ischemia is a new object in heart failure research. It is unclear why some arterial vessel could survive in transmural MI, more interestingly it is unknown if capillaries could be regenerated from the residue arterial vessel in MI. The role of capillary both in ischemic artery and nearby non-ischemic branch in MI development is an amazing challenge. It is unknown why occlusion of left branch of LCA could degenerate capillaries on right branch of LCA. Inflammation probably plays a role in this phenomenon, but the knowledge of its mechanism is totally lacking even it indicates a potential path to new treatment strategy of ischemic heart disease.
Abstract 434: Acidifying Nanoparticle Upregulates Autophagy and Enhances Cardiomyocyte Survival after Chemotherapy
Authors: Khatun Zehedina , Meng Lin , Martin Gregory , Jahan Tanjheela , Wei Lan , Yuan Hushan , Josephson Lee , Mekkaoui Choukri , Sosnovik David E , Blanton Robert M , Chen Howard H
Published: October 2019

Introduction:
Chemotherapy-induced cardiotoxicity remains prevalent and deadly, with no effective therapy to slow the progression to irreversible heart failure, which in the case of doxorubicin (Dox) can reach 50% mortality. Dox impact on cardiomyocytes (CMs) is multifocal, including oxidative stress, lysosome alkalinization, and apoptosis. PLGAs, poly(DL-lactide-co-glycolide), are FDA-approved polymers, form defined nanoparticles (NPs). We hypothesize that PLGA NPs target the lysosomal compartments, restore lysosomal acidity after Dox, and confer cardioprotective effects.

Methods:
We synthesized fluorescent PLGA NPs by click chemistry. In H9C2 myocytes exposed to 1-5 μM of Dox +/- 1 mg/ml of PLGA, we measured cell viability (MTT), lysosomal pH (OG-514), mitochondrial membrane potential (JC-1), and autophagy proteins (western blot). We further co-injected C57Bl6 mice with PLGA (10 mg/kg, i.v.) and Dox (15 mg/kg, i.p.), to image apoptosis (Annexin) and autophagy (cathepsin-activatable autophagy probe, ADN, unpublished) after 24 hrs, or 4 mg/kg Dox weekly, 5x, i.p. and echo after 3-4 weeks.

Results:
PLGA NPs formulated are of controlled size and valency, emits near-infrared fluorescence (Fig. A). In H9C2s, PLGA significantly improved survival after Dox (Fig. B), acidified lysosomes (Fig. C), did not impact cell energetics (Fig. D), and further restored autophagic flux (Fig. E). Imaging in Dox mice revealed significant apoptosis reduction and autophagy activation (Fig. F-H), and cardiac function recovery (Fig. I).

Conclusions:
PLGA NPs may represent a novel class of cardioprotective therapeutics of early chemotherapy stress, and with translational potential.
Abstract 445: Monitoring the Hemodynamic Status During Three Trimesters of Pregnancy and Non-pregnancy Periods
Authors: Chen Chih-Yu , Chang Chi-Wei , Wang Sheng-Hung , Wang Gin-Chung
Published: October 2019

Pregnancy is an important stage in women and is associated with delicate cardiovascular adaptation from non-pregnancy to pregnancy. Maternal hemodynamic changes are made to provide sufficient nutrients and oxygen to support the normal growth of the developing fetus. This study was designed to assess maternal hemodynamic status during three trimesters of pregnancy and non-pregnancy periods. Total 326 women (84 pregnant women and 242 age-matched non-pregnant women of childbearing age) between the ages of 20 and 44 participated in this non-invasive observational study. In this cross-sectional study, enrolled participants underwent blood pressure and radial pressure pulse measurements. In order to compare the hemodynamic status of different subjects, we recorded the systolic and diastolic blood pressure and calculated the first five harmonic amplitudes(C1~C5) and phases(P1~P5) of radial pulse wave using Fourier transform method. Compared with non-pregnant women, the maternal systolic and diastolic blood pressures were lower, and heart rate, C2, C4, and P1 were higher in pregnant women (Table 1). Those hemodynamic changes may be due to decreased arterial stiffness and peripheral arterial vasodilatation in pregnancy. In summary, a series of changes in maternal hemodynamic status can be observed during the trimesters of pregnancy, including lowering blood pressure and increasing harmonics of radial pulse. This study demonstrates the feasibility of non-invasive monitoring of the hemodynamic status of pregnant women, which could be used for early detection of pregnancy disorder.
Abstract 448: Predicting Blood Pressure Response to Fluid Bolus Therapy Using Neural Networks with Clinical Interpretability
Authors: Girkar Uma , Uchimido Ryo , Lehman Li-wei H , Szolovits Peter , Celi Leo , Weng Wei-Hung
Published: October 2019

Background:
Fluid bolus therapy (FBT), the rapid infusion of fluid, has been recommended as the primary-line treatment for acute hypotensive episode (AHE) that occurs in about 41% of patients in ICU. However, previous studies have reported that approximately one-third of the acute hypotensive patients do not successfully respond to FBT treatment. Avoiding the administration of FBT that will not successfully resolve AHE might prevent an inappropriate increase of the total fluid volume administered to ICU patients, potentially reducing their risk for severe organ dysfunction and increased mortality.

Methods:
Our study utilized regression models and attention-based recurrent neural network (RNN) algorithms and two large-scale information system databases, the multi-clinical MIMIC-ICU one and the multi-center Philips eICU CRD one, to predict the successful response to FBT among hypotensive patients in ICUs. We investigated both time-aggregated modeling and time-series modeling using RNN with the attention mechanism (AM) for clinical interpretability. The successful FBT is defined by intensive care experts as the presence of the maximum mean atrial pressure (MAP) > 1.15 * average (MAP) at least once, where maximum(MAP) is the maximal MAP from the FBT starting time to two hours after FBT, and average (MAP) is the average MAP from 30 minutes before FBT until 10 minutes after FBT.

Results:
The stacked RNN with AM yielded the highest accuracy of 0.852 and area under the curve (AUC) value of 0.925 when trained and tested on the MIMIC-ICU dataset. The top features learned from regression include the patient's respiratory rate, diastolic pressure, temperature, and bicarbonate and base excess levels in blood. Preliminary results from training and testing the RNN on the Philips eICU-CRD database yielded an accuracy of 0.812 and AUC value of 0.769. We were also able to identify timesteps close to the time of FBT administration as clinically meaningful using the RNN models with AM.

Conclusion:
This is the first study that utilizes machine learning for identifying hypotensive patients in ICUs who will have sufficient blood pressure recovery after FBT. Utilizing AM and identifying the top features learned also provided clinical interpretability to the models we used.
Abstract 451: Pde1 Promotes Development of Pulmonary Arterial Hypertension and Could Be a Novel Treatment Target
Authors: Kimura Mai , Kusumoto Dai , Komuro Jin , Katsuki Toshiomi , Ito Shogo , Hashimoto Hisayuki , Yuasa Shinsuke , Fukuda Keiichi
Published: October 2019

Backgrounds:
Pulmonary arterial hypertension (PAH) is a rare but fatal disease, with an estimated mean survival period in untreated patients of approximately 3 years. Pulmonary vascular remodeling is a hallmark of PAH. Pulmonary vasculature shows increased proliferation, irrelevant migration and apoptosis resistance of vascular cells such as pulmonary arterial smooth muscle cells (PASMCs) and endothelial cells. However, the molecular mechanism in the pathogenesis of PAH remains unclear. We previously performed genome-wide association study (GWAS) in Japanese patients with idiopathic / heritable PAH and healthy controls and identified novel disease related SNPs in
PDE1A
Abstract 453: Phenotyping by ECG Dynamics During Sleep Predicts Cardiovascular Disease Risk Factors in a Multicenter Study of Asymptomatic Middle-aged Community Adults
Authors: Lin Tracie K , Wendelken Daniel , O'Rourke Brian , Jones Steven R , Punjabi Naresh M , DeMazumder Deeptankar
Published: October 2019

Introduction:
ECG-based predictive analytics have typically focused on static assessment of beat-to-beat heart rate variability (HRV) during wakefulness. However, there is increasing evidence that quantification of time-related changes as well as non-beat-to-beat complexity indices, such as entropy, can provide important untapped insight.

Methods:
Analysis of HRV, QT variability (QTV), QT entropy (QTen), QT entropy rate (QTa) and RR entropy (RRen) in 5-min bins were performed on home polysomnographs of 6,300 asymptomatic community adults (Sleep Heart Health Study). Rate of change of ECG variables was quantified by linear regression in one- to four-hour epochs. Stepwise regression was used to identify age-, sex-, race-, comorbidity-, and sleep state-associated influences on ECG values.

Results:
Predictive multivariate models were generated for congestive heart failure, diabetes, obstructive sleep apnea, and history of myocardial infarction, each with sleep state-specific and ECG variable rate of change being of the highest predictive value in ECG-based models (Table 1).

Conclusion:
Although aggregate beat-to-beat HRV is associated with cardiovascular risk factors, unique time-varying and sleep stage-specific findings provide additional predictive power. By way of demonstrating that distinct classes of dynamic ECG features were predictive of each risk factor studied, our study suggests a potential role for patient-specific ECG phenotyping using a comprehensive analytical platform. Dynamic ECG assessment during sleep with attention to entropy-derived measures, in particular, may enhance precise risk stratification in otherwise low-risk individuals.
Abstract 466: Myopathy Causing Bag3
P209L
Protein Leads to Restrictive Cardiomyopathy Caused by Aggregate Formation and Sarcomere Disruption in Cardiomyocytes
Authors: Graf-Riesen Kathrin , Kimura Kenichi , Unger Andreas , Lother Achim , Hein Lutz , Daerr Jan , Braune Julia , Ooms Astrid , Li Guang , Wu Sean M. , Höhfeld Jörg , Linke Wolfgang A. , Fürst Dieter , Fleischmann Bernd K. , Hesse Michael
Published: October 2019

The co-chaperone BAG3 (Bcl-2 associated athanogene 3) is strongly expressed in cross-striated muscles and plays a key role in the turnover of muscle-proteins as a member of the CASA (chaperone-assisted selected autophagy) complex. An amino acid exchange (P209L) in the human BAG3 gene, caused by a single base mutation, gives rise to a severe dominant childhood muscular dystrophy, restrictive cardiomyopathy, and respiratory insufficiency. To get deeper insights into the pathophysiological mechanisms of the disease, we generated a transgenic mouse model of the human mutation BAG3
P209L
, in which a fusion protein consisting of the human BAG3
P209L
and the green fluorescent protein eGFP can be conditionally overexpressed. Ubiquitous overexpression of BAG3
P209L
-eGFP leads to a severe phenotype between the second and fourth week of life, including decreased body weight, skeletal muscle weakness, and heart failure. Echocardiography revealed that the BAG3
P209L
-mice suffer from restrictive cardiomyopathy and Sirius-red-staining of heart tissue showed extensive fibrosis. In cardiomyocytes, isolated from hearts of transgenic mice overexpressing BAG3
wt
-eGFP or BAG3
P209L
-eGFP, BAG3
wt
-eGFP stringently localizes to sarcomeres and intercalated discs, whereas cardiomyocytes from BAG3
P209L
-eGFP mice displayed formation of BAG3 containing aggregates and disruption of sarcomeres in
vivo
. While BAG3
P209L
-eGFP binding to á-Hsp70, Filamin C and á-HspB8 was unchanged it was less soluble than BAG3 and had a tendency to aggregate, thereby sequestering BAG3 and its clients. Depletion of the BAG3 pool leads to an impairment of CASA and accumulation of damaged proteins, causing sarcomere disintegration leading to restrictive cardiomyopathy.
Abstract 478: Identifying Signaling Pathways Regulated by Trophoblasts in Placental Vascular Development Using 3D Tissue Models
Authors: Kashpur Olga , Wallingford Mary C
Published: October 2019

The placenta is an essential yet transient organ that supports healthy pregnancy and normal fetal development. Placental vascular dysfunction is associated with preeclampsia, HELLP (hemolysis, elevated liver enzymes, low platelets), fetal growth restriction, hemorrhaging, preterm birth, and loss of life. Placental vascular dysfunction can also negatively impact long-term maternal and offspring health, increasing risk for cardiovascular disease, coronary artery calcification, and stroke later in life.

The vasculature of the maternal-fetal interface is uniquely characterized by the presence of trophoblast cells. Multiple trophoblast cell lineages serve essential functions in both the maternal vascular compartment and the feto-placental angioarchitecture. Functional roles for FGF2, VEGF, and angiopoietin signaling pathways in endothelial vasculogenesis and angiogenesis are well supported by a large body of literature, but there is a gap in knowledge of placenta-specific molecular mechanisms that account for the unique interaction of trophoblasts and endothelial cells. I hypothesize that trophoblasts generate angiogenic signals that promote vascular development at the maternal-fetal interface in both an autocrine and paracrine manner.

Using 3D assays, I evaluated the role of endovascular cytotrophoblast and syncytiotrophoblast cell lines in establishment of a vascular compartment. Trophoblasts harbor intrinsic angiogenic competency evident by their ability to form angiogenic sprouts and generate 3D vascular networks under defined conditions. My current research implements 3D bioassays, bio-engineered vessels, and chemical inhibition to further investigate paracrine angiogenic signaling between trophoblasts and endothelial cells.

Our work is the first to evaluate autocrine and paracrine angiogenic properties of trophoblasts under physiological 3D conditions that mimic development. When coupled with histological evaluation of human placenta, these systems will allow us to better evaluate and understand molecular mechanisms of placental vascular development and vascular dysfunction.
Abstract 487: Immune Response Factors in Patients With Diabetes Mellitus and Acute Coronary Syndrome
Authors: Glova Svetlana , Shlyk Sergey
Published: October 2019

Purpose:
To study cardiac remodeling in patients with ACS complicated with DM through analysis of laboratory parameters and echocardiogram.

Methods:
A total of 67 patients were prospectively enrolled (age range: from 36 to 79 years; average: 60,96 ± 9,22 years) with ACS who were admitted to Emergency Hospital. The patients were divided into 2 groups depending on the presence of DM: 23 patients with DM (age average: 65,09 ± 7,73 years) and 44 without DM (age average: 58,79 ± 9,19 years). Serum triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), high sensitive C reactive protein (hs-CRP), antibodies to LPS General Enterobacteriaceae, antibodies to LPS Re-Glycolipid were tested for all patients. Echocardiograms were obtained on all the patients, interventricular septal thickness (IVSd) and others parameters were measured by taking the mean values of three continuous heartbeat cycles in the expiratory state. All indicators were calculated using the statistics program Statistica, a P-value of < 0,05 was considered statistically significant.

Results:
There were no significant differences in the prevalence of smoking, family history of CVD, hypertension between groups. No differences were observed in the levels of serum hs-CRP, TC, HDL-C, LDL-C; but TG levels were significantly higher in patients with DM ( 3,16 ± 2,61 mmol/l) than in controls (1,75 ± 1,33 mmol/l, p<0,05). Serum antibodies to LPS General Enterobacteriaceae levels (441,52 ± 303,70 A.U.O.D) were also significantly higher in the DM group than in controls (271,41 ± 200,13 A.U.O.D, p<0,05). The levels of serum antibodies to LPS General Enterobacteriaceae were positively correlated with IVSd (r = 0,765, p<0,05).

Conclusion:
The data demonstrated, that patients with DM have a greater immune response which correlates with indicators of left ventricular remodeling. The mechanism of the cardiac function impairment, however, has not been clearly explained yet. The role of the immune response in the development of cardiac muscle remodeling is not fully understood. It Is currently considered that these changes may participate in the pathological process of left ventricular remodeling in patients with DM.
Abstract 506: Trpm4 Contributes to Ca
2+
-dependent Triggered Arrhythmias in Pathological Conditions
Authors: Vandewiele Frone , Jacobs Griet , Pironet Andy , Oosterlinck Wouter , Vennekens Rudi
Published: October 2019

Rationale:
TRPM4 is a Ca
2+
-activated non-selective cation channel that is abundantly expressed in the heart. Mutations in the
Trpm4
gene are associated with human cardiac conduction disorders, including Progressive Familial Heart Block type I (PFHBI) and Brugada Syndrome. However, the mechanistic role and
in vivo
significance of TRPM4 in the triggering of cardiac arrhythmias is still completely unclear.

Objective:
To investigate the role of TRPM4 during pathological Ca
2+
handling in the heart.

Methods and results:
Using three
in vivo
pro-arrhythmic assays, we found that

Trpm4
-/-

mice show a reduced arrhythmic burden compared to control mice. First, aconitine intoxication resulted in severe cardiac arrhythmias, both in WT and

Trpm4
-/-

animals, but

Trpm4
-/-

mice developed significantly less ventricular ectopic beats (VEBs) and showed a lower arrhythmic score. Second, during ischemia-reperfusion, induced by 30 min of LAD ligation, significantly more WT animals developed arrhythmias compared to

Trpm4
-/-

mice. Third, catecholaminergic polymorphic ventricular tachycardia (CPVT) mice, carrying mutations in RyR2, were subjected to a stress test. Significantly more

RyR
+/R2474S
-Trpm4
+/+

animals developed arrhythmias compared to

RyR
+/R2474S
-Trpm4
-/-

mice.

Conclusion:
Our data establish that TRPM4 represents a novel target in the prevention and treatment of cardiac arrhythmias.
Abstract 510: Spatial Transcriptomics Unveil ZBTB11 as a Regulator of Cardiomyocyte Degeneration in Arrhythmogenic Cardiomyopathy
Authors: Boogerd Cornelis J , Lacraz Grégory P , Vértesy Ábel , Perini Ilaria , de Ruiter Hesther , Brodehl Andreas , van der Kraak Petra , Huibers Manon , de Jonge Nicolaas , Junker Jan Philip , Vink Aryan , van Rooij Eva
Published: October 2019

Introduction:
Arrhythmogenic cardiomyopathy (ACM) is an inherited cardiac disorder characterized by progressive loss of contractile myocardium which is replaced by fibrous and adipose tissue, ventricular arrhythmias, and sudden cardiac death. Fibrofatty replacement extends transmurally with an epi-to-endocardial gradient, yet molecular differences between the transition regions are poorly characterized.

Methods and Results:
To explore molecular mechanisms underlying ACM we obtained an explanted heart of a 35-year-old male with a known pathogenic
PKP2
mutation, c.2544G>A. We utilized Tomo-Seq to acquire a genome-wide transcriptional profile with 100μm-spatial resolution, generating a transmural expression atlas of the ACM heart. Tracing transcriptional differences across the ventricular wall enabled us to identify clusters of genes specific to the myocardium and fibrofatty region. In addition, we detected restricted sites of active remodelling within the myocardium with a clearly distinct gene program. Amongst genes specifically enriched in this composite region was the Zinc Finger and BTB Domain-Containing Protein 11 (ZBTB11). Overexpression of ZBTB11 in human cardiomyocytes induced a differential gene expression profile with striking similarities to the composite region from the Tomo-Seq analysis. Most notably, ZBTB11 induced a TP53 mediated stress response including activation of apoptosis and autophagy. The presence of ZBTB11-positive cardiomyocytes flanking fibrofatty islands was confirmed in ACM patients harbouring other
PKP2
mutations, as well as ACM and DCM hearts with mutations in non-desmosomal genes. We are currently exploring the ZBTB11 transcriptional network, and its role in disease progression in human cardiomyopathies.

Conclusions:
Using a spatial transcriptomics approach on a human ACM heart we have identified ZBTB11 as a novel marker of cardiomyocyte degeneration in cardiomyopathies. ZBTB11 induces autophagy and apoptosis and therefore may be relevant for the development of biomarker assays and in identifying novel targets for therapies against cardiomyopathies.
Abstract 517: Glutaminolysis is Required to Initiate Myofibroblast Differentiation and Persistence During Stress
Authors: Gibb Andrew A , Lombardi Alyssa A , Murray Emma K , Tan Yinfei , Lorkiewicz Pawel K , Huynh Anh T , Kolmetzky Devin W , Arany Zolt , Kelly Daniel P , Margulies Kenneth B , Hill Bradford G , Elrod John W
Published: October 2019

Cardiac fibrosis occurs in ischemic heart failure, genetic cardiomyopathies, diabetes, and aging. While initially considered reparative, resident cardiac fibroblasts (CFs) activation/differentiation to myofibroblasts provide contractile and integral support; however, persistent activation leads to progressive cardiac dysfunction and maladaptive remodeling. Recent reports implicate acute and/or chronic changes in metabolism as a central driver for many cellular differentiation programs. Indeed, metabolite bioavailability is directly linked to the activity of epigenetic-modifying enzymes implicated in lineage commitment and differentiation. We recently identified αKG-dependent lysine demethylases as key contributors to myofibroblast formation. Here, TGFβ stimulated fibroblasts isolated from adult mouse hearts were subjected to next-gen sequencing methodologies (RNA-seq, ATAC-seq, and RRBS-seq) to identify dynamic modifications in chromatin architecture and DNA accessibility at gene loci critical to the myofibroblast gene program. Utilizing unbiased and stable-isotope metabolomics, we correlated chromatin remodeling with a significant decrease in abundance/utilization of s-adenosylmethionine, the methyl donor for cytosine and histone methylation. In addition, a significant increase in αKG abundance driven by enhanced glutaminolysis was observed. To investigate the significance of glutaminolysis and enhanced αKG biosynthesis, we treated CFs with a glutaminase inhibitor (CB-839) and evaluated differentiation. Treatment with CB-839 in the presence of TGFβ prevented activation of the fibrotic gene program (RT-qPCR) and myofibroblast formation. Furthermore, following TGFβ-induced differentiation, inhibition of glutaminolysis was sufficient to revert activated myofibroblasts to a quiescent non-fibrotic phenotype, even during sustained stress. Importantly, this phenomenon is reproducible in CFs derived from human HF patients. Collectively, these results suggest a primary role for metabolism in not only initiating differentiation, but also the persistence of myofibroblasts, potentially through epigenetic-dependent gene transcription, providing new therapeutic targets to treat fibrosis.
Abstract 518: Pharmacological Inhibition of Human Antigen R (HuR) Blunts fibroblast Activation and Cardiac Fibrosis
Authors: Green Lisa C , Anthony Sarah R , Slone Samuel , Alam Perwez , Xu Liang , Tranter Michael
Published: October 2019

Myocardial fibrosis is associated with many cardiac diseases and often leads to a worsened prognosis. In a healthy heart, cardiac fibroblasts are responsible for maintaining the extracellular matrix (ECM). In response to stress or injury, however, the fibroblasts activate to myofibroblasts and begin proliferating, migrating, and depositing excess ECM. This leads to decreased compliance and contractility of the myocardium, furthering the progression to heart failure. Dampening the chronic activation of fibroblasts, therefore, is an attractive target for future cardiac therapeutics. Human Antigen R (HuR) is an RNA binding protein known to stabilize mRNA through binding to AU rich regions in the 3’UTR. Our lab has previously utilized a myocyte-specific knockout of HuR to show that HuR plays an important role in cardiac fibrosis through mediating TGFβ gene expression in the myocytes. Additionally, pharmacological inhibition of HuR markedly reduced interstitial cardiac fibrosis in an 11-week transverse aortic constriction (TAC) mouse model of heart failure, quantifying the fibrosis with Masson’s Trichrome Stains, western blots, and qPCR of profibrotic markers.

The goal of this work is to identify the functional role of HuR in mediating pro-fibrotic gene expression and ECM remodeling activity in cardiac fibroblasts. Our results demonstrate that HuR inhibition blunts the activation and wound healing activity of primary adult cardiac fibroblasts. Specifically, utilizing an
in vitro
scratch/wound healing assay we show that HuR inhibition significantly prolongs wound closure time and blunts the expression of profibrotic genes (e.g. collagen1a1, periostin, TGFb, fibronectin). Ongoing studies will determine the effect of HuR inhibition in a two-week isoproterenol pump (30mg/kg/day) model. Quantification of fibrosis and upstream signaling of fibroblast activation, such as TGFβ-dependent phosphorylation of SMAD2/3, will be assessed to determine the role of HuR in the initiation of fibrotic signaling.
Abstract 519: Desmin Protects Cardiomyocyte Nuclei From Microtubule-dependent Collapse
Authors: Heffler Julie , Shah Parisha P , Robison Patrick , Phyo Sai , Veliz Kimberly , Bogush Alexey , Rhoades Joshua , Jain Rajan , Prosser Benjamin L
Published: October 2019

Alterations to mechanical forces have been long-appreciated to be sufficient to drive cardiac pathophysiological remodeling; however, the mechanism by which cardiomyocytes sense and transduce mechanical stressors remains poorly understood. In part, mechanical forces can be transduced to transcriptional responses by direct strain transmission to the nucleus via the Linkers of the Nucleo- and Cytoskeleton (LINC) complex, which couples the cytoskeleton to the nuclear lamina and DNA. While LINC complex mutations are known to cause cardiomyopathy, cytoskeletal-LINC interactions are understudied in the cardiomyocyte. To probe these interactions, we acutely disrupted the LINC complex as well as microtubules, actin, and intermediate filaments and assessed the consequences on baseline nuclear homeostasis in the cardiomyocyte. Our result show that a balance of microtubules and desmin intermediate filaments is required to maintain nuclear shape and the fidelity of the nuclear envelope and lamina. Upon acute depletion of desmin (or Nesprin-3, its binding partner in the LINC complex), microtubules drive infolding of the nuclear membrane. This results in DNA damage, a loss of genome organization, and broad transcriptional changes. Desmin knockdown also causes compromised excitation-contraction coupling and contractile function. Together, our data suggest that a balance of forces imposed by intermediate filaments and microtubules is required to maintain nuclear structure and genome organization in the cardiomyocyte, and that this process is important for maintaining proper myocyte health and function.
Abstract 524: Activated Fms-like Tyrosine Kinase 3 Receptor Prevents Ventricular Remodeling Induced by Ang Ii Through the Attenuation of Autophagy
Authors: Ma Wenzhuo , Gao Chenying , Zhao Zhenghang
Published: October 2019

Aim:
FMS-like tyrosine kinase 3 (Flt3) is a receptor tyrosine kinase. This study was to determine whether activation Flt3 could regulate autophagy ameliorate AngII-induced heart cardiac remodeling and to elucidate the mechanisms of action.

Methods:
In vivo cardiac remodeling was induced in male C57BL/6 mice by implanting subcutaneously osmotic minipumps releasing Angiotensin II (Ang II) for 28 days (1100ng/kg/min). Flt3 ligand (FL) was administered intraperitoneally (5μg/mouse/2days). Heart hypertrophy, fibrosis and function were evaluated based on echocardiography, histological and biochemical measurements. In vitro, hypertrophy was induced by Ang II on adenovirus vector-mediated overexpression Flt3 receptor in H9c2 cells, and NRCMs. Crystal violet staining, flow cytometry and TUNEL were used for
in vitro
experiments. The levels of signaling proteins were measured using western blotting, while the expression of the relevant genes was analyzed using real-time qRT-PCR.

Results:
Echocardiography demonstrated that Ang II induced marked damaged heart function, while cardiac Flt3 receptor activation significantly decrease left ventricular internal dimension at end-diastole (LVIDd), left ventricular posterior wall thickness at end-diastole (LVPWd), and increase ejection fraction (EF%) and fractional shortening (FS%). FL-treated mice showed a significant attenuation of cardiac hypertrophy, ratios of heart weight/body weight (HW/BW) and heart weight/tibia length (HW/TL), as well as cardiac fibrosis and apoptosis. Additionally, the autophagic levels in cardiomyocytes of FL-treated mice were distinctly decreased as evidenced by expression of LC3 in immunohistochemical staining and western blotting. In H9c2 cells with adenovirus vector-mediated overexpression of Flt3 and neonatal rat cardiomyocytes, FL treatment significantly decrease the cell size, apoptosis and autophagy induced by Ang II. Additionally, using rapamycin or metformin, respectively canceled FL protective effects.

Conclusion:
Flt3 activation suppresses Ang II-induced cardiac hypertrophy and apoptosis via AMPK /mTOR/ FOXO3a autophagy signaling pathway. These results provide evidence supporting Flt3 as a novel therapeutic target in cardiac remodeling.
Abstract 526: A Transcriptomic Analysis of Cardiac Myofibroblasts Reveals Novel Anti-fibrotic and Immunomodulatory Genes Modulated by CDC-Derived Exosomes
Authors: Sinibaldi Everett J , Sim Fraser J , Lang Jennifer K
Published: October 2019

Background:
Cardiac fibroblasts are the most prevalent cell in the heart and play an important role in both the healthy and diseased myocardium. Following myocardial infarction, TGF-β secretion promotes a phenotype transition of fibroblasts to activated myofibroblasts. We have previously shown that CDC-derived exosomes promote cardiomyocyte proliferation and survival, stimulate angiogenesis, and polarize cardiac macrophages to a unique Arg1-high phenotype. We hypothesized that CDC-derived exosomes modulate the gene expression of myofibroblasts to attenuate fibrosis in the remodeling heart.

Methods:
We took a genomics-based approach to investigate CDC-exosome mediated differential gene expression and regulation of operant signaling pathways in TGF-β induced ventricular myofibroblasts. Cardiac fibroblasts were isolated from C57BL/6 mice (n=3) using a Langendorff-free method of
in situ
enzymatic dissociation. Cells were plated at 1x10
5
cells/mL, serum depleted to induce cell cycle arrest and exposed to 4 different conditions: media alone, TGF-β (4 ng/ml) “myofibroblasts”, CDC-exosomes (20 μg/ml), or TGF-β and CDC-exosomes. After 24 hours, RNA was extracted and analyzed by RNA-seq.

Results/Conclusions:
Gene ontology analysis showed attenuation of a pro-fibrotic gene expression profile in the TGF-β + CDC-exo group relative to TGF-β treatment alone. Genes involved in blunting of the pro-fibrotic response (
Mmp14
and
Qsox1)
, as well those implicated in attenuating the transition of fibroblasts to myofibroblasts (
Gsto1
) were also upregulated in CDC-exosome treated myofibroblasts (edgeR; FDR-corrected p<0.05). Interesting, we found a highly significant enrichment of genes involved in macrophage migration (
Kars
,
Mmp14
, and
Tnfsf18
) in the CDC-exosome treated myofibroblasts relative to the TGF-β group (GO:1905523, p=8.42x10
-6
). These data suggest active cross talk between myofibroblasts and macrophages and highlight a novel immunomodulatory role of CDC-derived exosomes on myofibroblasts post MI.
Abstract 545: A Multifunctional Genetic Probe for Investigating Mitochondrial Calcium Dynamics in Cardiac Cells
Authors: Ernst Patrick J , Xu Ningning , Zhao Meng , Zhang Jianyi (Jay) , Liu Xiaoguang (Margaret) , Zhou Lufang
Published: October 2019

Introduction:
Calcium cycling plays a critical role in regulating function of cardiomyocytes (CMs) under both physiological and pathological conditions. Among their many important functions, mitochondria are known to involve in calcium handling. However, little is known about the calcium dynamics of human stem cell-derived cardiomyocytes (hiPSC-CM) and what little is known shows much greater variability than what is seen in adult cardiomyocytes.

Methods:
We produced adenovirus encoding the red Ca
2+
indicator RCaMP prepended with a mitochondrial targeting sequence fused to the green Ca
2+
indicator GCaMP with a cleavable linker. We then used this virus to induce expression of this calcium probe in CMs & recorded calcium activity with a confocal microscope.

Results & Discussion:
Mitochondrial targeting was confirmed by confocal imaging showing GCaMP (green), mRCaMP (red), and costaining with Mitotracker Deep Red (Magenta) (Figure 1A, 1B). Probe functionality was validated by observing beat-by-beat calcium dynamics in paced neonatal rat CMs with and without blocking mitochondrial calcium uptake with the mitochondrial calcium uniport inhibitor Ru360. Recording GCaMP and mRCaMP dynamics in adult CMs (Figure 1C) showed synchronous beat-by-beat calcium activity in the cytosol and mitochondria. However, iPSC-CMs (Figure 1D) showed variable mitochondrial activity, with some synchronous mitochondria and some showing inverse activity.

Conclusions:
hiPSC-CMs and adult CMs show differences in beat-by-beat mitochondrial calcium dynamics, offering a potential investigatory target for improving the therapeutic effect of stem cell-derived heart therapies.
Abstract 567: Fgf21 as a Biomarker for Metabolic Stress in Heart Failure
Authors: Sommakia Salah , Almaw Naredos , Nguyen Elizabeth , Ramadurai Dinesh , Shankar Thirupura , Navankasattusas Sutip , Campbell Robert , Drakos Stavros , Chaudhuri Dipayan
Published: October 2019

FGF21, an important metabolic regulator, has recently been suggested as a biomarker for heart failure (HF). FGF21 is involved in the integrated mitochondrial stress response, and has been shown to be upregulated with mitochondrial DNA damage, which occurs more frequently in dilated cardiomyopathy. In this study, we investigated whether FGF21 can be used as a biomarker for metabolic stress in HF. We collected blood and cardiac tissue samples from ischemic and non-ischemic HF patients who have undergone VAD transplantation. We also collected blood and tissue from mice with HF due to 1) combination of transverse aortic constriction and coronary artery ligation (TAC+Lig) or 2) cardiac-specific knockout of the mitochondrial transcription factor A (Tfam). Serum FGF21 levels were measured using Enzyme-linked immunosorbent assay (ELISA). Messenger RNA was extracted from the tissue and FGF21 gene expression was measured using real-time quantitative PCR (qPCR). Immunohistochemical staining was performed on tissue sections (either paraffin embedded or frozen) to observe FGF21 levels. Serum FGF21 was elevated in human HF patients compared to healthy controls, as well as in both mouse models of HF. In human patients, cardiac FGF21 gene expression was upregulated 2.2-fold compared to donors. In the TAC+Lig mouse model we observed a 3.37-fold increase, while the Tfam knockout model which has severe mitochondrial damage exhibited a 218-fold increase in cardiac FGF21 gene expression. Further qPCR assays revealed changes in FGF21 gene expression in the liver and white fat of TFAM-KO, indicating metabolic stress on other organs resulting from HF. In conclusion, serum FGF21 is elevated in multiple models of HF, and appears to have both cardiac and extra cardiac sources. Future work will investigate 1) whether there is a correlation between FGF21 levels and mitochondrial damage, and 2) the signaling pathway resulting in metabolic stress to other organs in HF.
Abstract 570: Mechanism Of Mitochondrial Calcium Uniporter Regulation
Authors: Garg Vivek , Paranjpe Ishan , Unsulangi Tiffany , Suzuki Junji , Milescu Lorin S , Kirichok Yuriy
Published: October 2019

Calcium uptake by mitochondria plays an important role in sequestering cytosolic calcium, regulating ATP production and maintaining the redox homeostasis. Mitochondrial calcium uniporter (MCU), a macromolecular channel complex that resides in the inner mitochondrial membrane, is the primary electrogenic pathway for calcium influx into the matrix. Because calcium uptake by mitochondria is dictated by the kinetic equilibrium between the influx and efflux machinery, the patch clamp is the best method to measure electrogenic MCU activity in isolation from the efflux mechanisms. Here we report the development of a system for heterologous expression of MCU and its associated subunits, essential MCU regulator (EMRE), MCUb and MICU1–3. Using this system, we investigated the biophysical properties of the MCU pore and its regulation. The system is based on a recombinant cell line (Drp1
-/-
mouse embryonic fibroblasts) in which knockouts for all subunits of the MCU complex have been generated. This system allowed both optical and direct electrophysiological studies of the structure-function relationships in the MCU complex with a relative ease in comparison to other cell lines. We confirmed the essential role of pore-forming MCU and EMRE subunits in mediating the MCU current. Importantly, fast-step solution exchange and single-channel recordings allowed us to gain novel insights into the biophysical properties of MCU e.g. inward rectification, kinetics of activation and selectivity to monovalent vs divalent ions.
Abstract 579: Involvement of the Alpha 1A-Adrenergic Receptor in the Cardiac Adaptation to Physiological Stress
Authors: Kaidonis Xenia , Niu Wenxing , Chan Andrea Y , Kesteven Scott , Wu Jianxin , Iismaa Siiri E , Feneley Michael , Graham Robert M
Published: October 2019

The ‘fight or flight’ response, involving sympathetic nervous system activation and catecholamine release, is central to survival. Resulting activation of adrenergic receptors (ARs) drives physiological responses, such as positive inotropy, which to date has been attributed solely to β
1
-AR/Gs/adenylyl cyclase/protein kinase A pathway-activation. We previously demonstrated that overexpression of the α
1A
-AR is cardioprotective in rodents in the setting of pathological cardiac stress; a finding in agreement with studies of α
1A
-AR inactivation. However, it remains unknown if α
1A
-ARs also protect the heart from physiological stress. Using a tamoxifen-inducible, cardiomyocyte-specific α
1A
-AR knockdown mouse model, we evaluated cardiac responses to swim exercise. Treatment of adult (8-12 week) mice with 4-OH tamoxifen (Tam) resulted in a 7.4 fold decrease (p<0.001) in cardiac α
1A
-AR mRNA levels, with no compensatory changes in expression of β
1
-, β
2
- or α
2
-AR subtypes. A 90 minute, twice daily, four-week swim challenge induced eccentric cardiac hypertrophy, with Tam- and vehicle-treated mice displaying similar increases in heart weight/tibia length (mean increase: 1.4 and 1.6mg/mm, respectively; p<0.001 vs sedentary mice) and left ventricular chamber radius (mean increase: 0.16 and 0.17mm, respectively; p<0.001 vs sedentary mice) with no change in wall thickness. Consistent with physiological hypertrophy,
Igf-1
mRNA increased 1.7 and 0.7 fold (p=0.004 vs sedentary mice), respectively, with no increase in
Nppb
,
Myh7
or
Acta1
mRNA. Cardiac function, assessed by micromanometry and echocardiography, showed increases in dP/dt min/EDV (mean: -117 vs -150 mmHg/s/μL; p=0.011), end-diastolic volume (mean: 76.9 vs 68.0μL; p=0.038) and end-systolic volume (mean: 29.4 vs 21.9μL; p=0.018), as well as a decrease in ejection fraction (mean: 63 vs 68%; p=0.046) in Tam- compared with vehicle-treated mice, respectively. Thus, despite a similar hypertrophic response, mice with cardiomyocyte-specific α
1A
-AR inactivation showed an impaired contractile response to a sustained swim challenge. These findings are consistent with cardiomyocyte α
1A
-ARs playing an important role in maintaining cardiac contractility in response to physiological stress.
Abstract 580: Cardiovascular Risks of Oxidative DNA Damage
Authors: Lowran Kaitlin , Fuelle Ann , Popp Phillip , Wu Colin G
Published: October 2019

G-quadruplexes (or G4s) are nucleic-acid structures formed by guanine-rich sequences. G4s must be timely unfolded in cells; otherwise, they can interfere with DNA replication, RNA transcription, and other essential processes. Guanine bases are susceptible to forming 8-oxoguanine (8oxoG) as a result of oxidative damage. Although 8oxoG-modified DNA sequences can still fold into stable G4s, it is not known how 8oxoG4s are removed in human cells. We have shown previously that the FANCJ DNA helicase targets G4s using an AKKQ amino acid motif and unfolds them with its motor activity. Here, we have examined the interactions of FANCJ with various 8oxoG4s using biolayer interferometry and fluorescence spectroscopy. We show that a FANCJ AKKQ peptide alone can recognize G4s independently. Moreover, this motif binds to 8oxoG4s with greater affinities. A detailed description of the mechanisms by which 8oxoG4s are repaired is essential for understanding how human hearts respond to oxidative stress. To test the importance of FANCJ AKKQ-G4 interactions in cells, we measured the total extent of oxidative DNA damage in human cardiomyocytes by single-cell electrophoresis. Cells that overexpress FANCJ can readily overcome the chemical stress induced by hydrogen peroxide treatment and the G4-stabilizing compound telomestatin. On the contrary, cells that produce a FANCJ ADDQ mutant, which cannot interact with G4s, resulted in an accumulation of 8oxoG4s. Based on this evidence, FANCJ plays an important role to alleviate the damage caused by oxidative stress. In future experiments, we plan to further examine the cardiovascular risks of DNA damage caused by FANCJ malfunctions.
Abstract 600: Anti-Angiogenic Effects of Circulating Exosomes From Patients With Acute Coronary Syndrome: Potential Role of miR-199a and miR-125a
Authors: Dantas Ana Paula V , Bobi Joaquim , Ortega-Paz Luis , Amin Ahmed , Pujol-Lopez Margarida , Lazaro Iolanda , Sabate Manel , Brugaletta Salvatore
Published: October 2019

Circulating exosomes have a great impact in human health as a biomarker or as messengers in intercellular signaling. In this study we aimed to determine how miRNA profile in circulating exosomes interfere with angiogenic phenotype of endothelial cell (EC) during acute event of coronary syndrome. Exosomes were purified from serum of patients with non-ST segment elevation myocardial infarction in the acute phase (NSTEMI, n=34) during percutaneous coronary intervention. Healthy donors (n=23) were included as control. Purified exosomes were quantified and characterized by nanoparticle tracking analysis (Nanosight). Healthy EC (HUVEC) were treated for 48h with labeled exosomes (5x10
5
particles/1x10
6
cells) and tested for their angiogenic potential (migration and tube formation) and mRNA expression. Exosome miRNA profile was determined by miRNA array. Exosomes levels were markedly increased in NSTEMI (1.3x10
9
particle/ml) vs control (7.5x10
8
particle/ml; p=0.02). HUVEC treatment with healthy exosomes improve migration and tube formation compared to untreated HUVEC. Nevertheless, exosomes from NSTEMI patients, in the acute phase lack their pro-angiogenic potential (Fig A). Network analysis of exosome miRNA and HUVEC mRNA expression revealed a correlation of increased miR-199a and miR-125a expression with decrease of components involved in EC sprout and stabilization (Fig B). Circulating exosomes have an important role in the control of angiogenesis. However, in the acute phase of NSTEMI intercellular communication via exosome is modified and exert an inhibitory effect on angiogenesis. These results could contribute to the progression and outcomes of the disease.
Abstract 614: Using Intact Trabeculae to Determine the Effect of Myosin-Modifying Drugs on Work, Power, and Mechanical Control of Relaxation
Authors: Schick Brianna M , Bukowski Melissa J , Chung Charles S
Published: October 2019

Background:
Heart failure and especially heart failure with preserved ejection fraction are significant burdens on health. Intact cardiac trabeculae may reveal functional changes that cannot be seen in other ex vivo (skinned, single molecule) preparations. For example, using intact trabeculae, we have shown that relaxation is mechanically controlled by the lengthening strain rate at end systole, not afterload.

Objective:
We sought to evaluate the effect of myosin activator Omecamtiv Mercarbil (OM) and inhibitor Mavacamten (Mav) on physiologic function in intact trabeculae.

Methods/Results:
Afterload-clamp protocols were applied to intact cardiac trabeculae from Sprague Dawley rats to simulate physiologic work-loops and evaluate mechanical control of relaxation. Both OM and Mav reduced stroke work (force x length) by >50% and power (force x velocity) by ~50% at doses reducing developed force by 50%. These were mediated by dose-dependent reductions in both force and shortening length. We have recently reported preliminary results that OM improves contraction-relaxation coupling and makes the relaxation rate more sensitive to strain rate in a dose-dependent manner. Mav does not lead to significant changes in contraction-relaxation coupling at any dose; Mav alters the sensitivity of relaxation rate to strain rate only at doses that reduce developed force by 50%.

Summary/Perspective:
Intact rat cardiac trabeculae reveal function mimicking physiology. OM and Mav show remarkable similarities in force, work, and power, which may be due to the high expression of alpha-myosin heavy chain. OM treatment not only modified contractility but increased sensitivity of the relaxation rate to strain rate in a dose dependent manner, which may explain why diastolic dysfunction is not more prevalent in clinical studies. Mav appears to only modify the attachment of crossbridges as expected.