bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 19453: Mechanical Unloading with a Micro LVAD after Acute Myocardial Infarction Reduces Adverse Cardiac Remodeling and Left Ventricular Systolic Asynchrony
Authors: Wei Xufeng , LI Tieluo , Sanchez Pablo , Williams Katrina , Li Shuying , Zhang Pei , Wu Zhongjun , griffith Bartley
Published: April 2024

Introduction:
Mechanical stress plays a critical role during cardiac remodeling post-MI. LVADs can provide circulatory support and profound mechanical unloading both to the preload and afterload of the left ventricle. To demonstrate that short-term cardiac unloading with a left ventricular assist device (LVAD) after an acute myocardial infarction (MI) can prevent cardiac remodeling and improve heart function.

Methods:
Adult ovine hearts were unloaded with an axial-flow LVAD (Impella LD) during the first 2 weeks after an acute MI and were analyzed for 10 more weeks (n=8, MI+LVAD group). Eight sheep with a MI only and 4 sham sheep were used as controls. Regional diastolic and contractile strain in the left ventricle was measured by sonomicrometry. Apoptosis, hypertrophy, and the related ultrastructures were studied regionally in the remote zone and the non-ischemic adjacent zone. Left ventricular systolic asynchrony was analyzed by sonomicrometry.

Results:
The regional myocardial strain (stretch) was minimized during the unloading period and even attenuated at 12 weeks compared to the MI only group. LV dilation and cardiac dysfunction were alleviated in the unloaded animal at 12 weeks (EDV: 81.9±5.4 ml vs. 105.9±9.5 ml; EF value: 39.3±4.2% vs. 46.4±1.8%, p<0.05). Infarct size was smaller in the unloaded animal at 12 weeks although the initial infarct size had no statistical difference in the two groups. Regional apoptosis, hypertrophy, and ultrastructural changes in the adjacent zone were prevented by the short-term LVAD unloading and the Calcineurin/BAD apoptotic pathway and the Raf/MEK/ERK hypertrophic pathway were involved. Left ventricular systolic asynchrony was evident among the remote zone, adjacent zone, and infarcted zone in the MI group, but reduced in the unloaded group.

Conclusion:
Short-term LVAD unloading can reduce apoptosis, hypertrophy, prevent left ventricular systolic asynchrony, and improve heart function during the post-infarct period. This translational study supports the application LVAD at the early stage post MI to prevent cardiac remodeling rather to “reverse” remodeling at the end-stage of heart failure.
Abstract 19472: Clinical and Angiographic Factor for the Mismatch Between Myocardial Perfusion Imaging and Pressure-Derived Fractional Flow Reserve
Authors: Yamaguchi Tomoyuki , Kubo Takashi , Shiono Yasutsugu , Ino Yasushi , Tanimoto Takashi , Nakanishi Hiroko , Sougawa Hiromichi , Orii Makoto , Shimamura Kunihiro , Yamano Takashi , Ishibashi Kohei , Hirata Kumiko , Imanishi Toshio , Akasaka Takashi
Published: April 2024

Background:
Myocardial perfusion imaging (MPI) with single-photon emission computed tomography (SPECT) is well-established modality to detect myocardial ischemia noninvasively. But it has been reported that MPI can underestimate ischemic region of myocardium, particularly in patients with multivessel coronary artery disease or previous myocardial infarction.

Method:
We analyzed the records of MPI and pressure-derived fractional flow reserve (FFR) retrospectively, and investigated what is the clinical and angiographic factor of discordance between MPI and FFR result. Myocardial ischemia is defined by an FFR≤0.75. Adenosinse or exercise Thallium
201
scintigraphy was underwent within 3 months before the FFR study. The clinical and angiographic features were compared with the patients who have myocardial ischemia identified by both MPI and FFR (concordance group).

Result:
Two hundred and sixty-three vessels in 220 patients were enrolled. Thirty-nine vessels in 37 patients were FFR-positive (i.e.FFR≤0.75), but MPI-negative (discordance group). Thirty patients (81.1%) in discordance group have multivessel coronary artery disease, and 18 patients (37.8%) have previous myocardial infarction. To compare with concordance group (40 vessels in 37 patients), there were no significant differences in basic characteristics, angiographic lesion complexity, and minimum lumen diameter. Two groups have same frequency of history of infarction (discordance group 46.2% vs. concordance group 42.5%; p=ns), but non-infarct-related-arteries were more often included (and misdiagnosed) in discordance group than concordance group (83.3% vs. 50%; p<0.05).

Conclusion:
In patients with previous myocardial infarction, MPI may underestimate myocardial ischemia. MPI should be carefully interrupted in these patients, and the measurement of FFR should be considered to evaluate myocardial ischemia accurately.
Abstract 19478: The Protective Effect of Beta3-Adrenergic Signaling Occurs via Differential Phosphorylation of nNOS in Cardiac Myocytes
Authors: Watts Vabren L , Sepulveda Fernando M , Cingolani Oscar H , Ho Alice S , Niu Xiaolin , Kim Rosa , Miller Karen L , Vandegaer Konrad , Bedja Djahida , Gabrielson Kathleen L , O'Rourke Brian , Kass David A , Barouch Lili A
Published: April 2024

Rationale:
Stimulation of β3-adrenoreceptor (β3-AR) signaling improves left ventricular function via a nNOS/NO-dependent manner in hypertrophied and failing animal hearts. nNOS, which is expressed in cardiac myocytes, is regulated by modification of stimulatory phosphorylation residue Ser1412 and inhibitory residue Ser847. However, how differential phosphorylation of these residues contribute to cardiomyocyte β3-AR-mediated NOS activation and signaling has yet to be explored.

Objective:
The aim of this study is to identify the molecular mechanisms involved in β3-AR-dependent regulation of nNOS activation and its downstream signaling in cardiomyocytes in the setting of hypertrophy.

Methods and Results:
In neonatal rat ventricular cardiomyocytes isolated from 4 day old pups, 48 hours of ET-1or 72 hours of norepinephrine lead to increased cell size and β3-AR mRNA. In hypertrophied cells, specific β3-AR agonist BRL-37433 induced NOS activity, nNOS phosphorylation at site Ser1412, dephosphorylation of site Ser847, and ROS suppression. BRL-dependent NOS activity and ROS suppression were attenuated by the nNOS inhibitor L-VNIO. NOS activity was also attenuated in phosphomimetic mutants Ser1412A (constitutively dephosphorylated) and Ser847D (constitutively phosphorylated). However, BRL failed to reduce ROS in the presence of Ser847D. In addition, Akt inhibition decreased BRL-induced Ser1412 phosphorylation and NOS activity, while Gi/o blockade altered BRL-regulation of both phosphorylation sites, NOS activity, and ROS reduction. In vivo, BRL administration completely dephosphorylated Ser847 and moderately increased Ser1412 phosphorylation in mice hearts under pressure overload.

Conclusion:
Our data suggest that β3-AR regulates myocardial NOS activity and ROS via alterations in nNOS phosphorylation in hypertrophied myocytes and failing hearts. This is the first study to demonstrate a role for nNOS phosphorylation as a key factor in cardiomyocyte and β3-AR signaling. These results contribute significantly to our understanding the protective properties of β3-AR signaling during cardiac sympathetic overdrive, and will ultimately aid in drug discoveries that target molecular mechanisms to treat heart failure.
Abstract 19487: Simvastatin Loaded High-Density Lipoprotein Nanoparticles Reduce Inflammation in Atherosclerotic Plaques by Directly Acting on Plaque Macrophages and Inflammatory Monocytes
Authors: Tang Jun , Duivenvoorden Raphael , Hewing Bernd , Izquierdo-Garcia David , Mieszawska Aneta J , van Rijs Sarian M , Cormode David P , Ozcan Canturk , Kuan Emma L , Martel Catherine , Lobatto Mark E , Stroes Erik S , Randolph Gwendalyn J , Fuster Valentin , Fisher Edward A , Fayad Zahi A , Mulder Willem J
Published: April 2024

Rationale: Although statins have been shown to have anti-inflammatory pleiotropic effects in experimental studies, the poor plaque targeting of orally administered statins limits their direct anti-inflammatory therapeutic effect. To that end, we have developed a simvastatin loaded high-density lipoprotein nanoparticle ([S]-rHDL), which has an improved plaque bioavailability and therefore exerts a higher therapeutic effect in apolipoprotein E knockout (ApoE KO) mice than orally administered simvastatin. The purpose of the current study is to understand the mechanism of this potent anti-inflammatory effect.

Methods and Results: [S]-rHDL was found to specifically target plaque macrophages by fluorescence microscopy (a). To investigate the targeting efficiency of [S]-rHDL to monocytes/macrophages, we intravenously injected [S]-rHDL in ApoE KO mice (n=3/time point) and analyzed the cells from aortas and blood by flow cytometry. [S]-rHDL was found to target macrophages and monocytes in aortas (b), and to target inflammatory Gr-1hi monocytes more efficiently than anti-inflammatory Gr-1lo monocytes in blood (c). Last, laser capture microdissection was used to isolate plaque macrophages (n=7), and quantitative RT-PCR was used to measure their mRNA level of TNF-α, the hallmark of macrophage inflammation, which was significantly reduced (d). All the above data support our hypothesis that [S]-rHDL acts on inflammatory monocytes and plaque macrophages and thereby exerts a strong anti-inflammatory effect on atherosclerotic plaque.

Conclusion: In ApoE KO mice, [S]-rHDL specifically targets plaque macrophages. [S]-rHDL also locally acts on macrophages in plaque and preferentially targets pro-inflammatory monocytes in blood, which results in a strong anti-inflammatory effect. This nanotherapy may represent a potent addition to the current standard of care for atherosclerosis patients.
Abstract 19493: In Type 1 Diabetes Decreased Bone Marrow Neuronal Support Shifts Normal Hematopoiesis Towards the Generation of (C-C Motif) Receptor 2 Monocytes
Authors: Grant Maria B , Bhatwadekar Ashay D , Hu Ping , Hazra Sugata , Caballero Sergio , Mohr Susanne , Abcouwer Steven F , Saban Daniel R , Chan-Ling Tailoi , Busik Julia V , Raizada Mohan K
Published: April 2024

We previously showed that in both type 1 (T1D) and type 2 diabetes loss of bone marrow innervation leads to circadian dysregulation of hematopoietic stem cell (HSC) release from bone marrow (BM) into the circulation. In this study, we extended these findings to humans with T1D and used T1D rodents to examine the role of key neurotransmitters/neuropeptides in the differentiation and the fate of HSCs. Diabetic (n=5) and control (n=5) subjects underwent a 2 hr blood sampling for 24 hr. Diabetic patients showed an increase in the amplitude of the peak and a phase shift (6 hrs) of the peak compared to controls (p<0.001). In marked contrast, CD34
+
cells release in diabetics showed no circadian pattern while controls did. In the long bones of T1D mice, immunodetection of calcitonin gene related peptide was reduced by 65% (p<0.05), neuropeptide Y by 67% (p<0.05), acetylcholine by 51% (p<0.05), and somatostatin by 50% (p<0.05). BM cells from T1D mice showed depletion of Side Population-HSCs but increased numbers of monocyte/macrophage colony forming units. BM supernatant of T1D mice showed increased levels (2.5-fold, p<0.002) of macrophage-colony stimulating factor (M-CSF/CSF-1, a stimulator of monocyte generation) and increased levels IL-1β (2-fold, p<0.05) and IL-27 (3-fold, p<0.01). Chimeric mice (transplanted with gfp-expressing HSC) were made T1D using streptozotocin (n=12) and compared to controls (n=12). T1D retinas, kidneys and brains (enzymatically-dissociated and analyzed by flow cytometry) showed a 10-fold, 6-fold, and 4-fold increase in CD11b
+
/CD45hi/ (C-C motif) receptor 2 (CCR2
+
) populations compared to controls. Immunohistochemistry of these tissues showed lba
+
resident microglia that exhibited a ramified morphology suggesting an inflammatory activation by extravasated BM cells. Our data suggests that in diabetic subjects, circadian dysregulation of monocyte and CD34
+
cell release exists. Our rodent studies support that the loss of BM neurotransmitter regulation (bone marrow neuropathy) may shift hematopoietic towards the generation of excessive numbers of CCR2
+
monocytes and reduced reparative endothelial progenitors which can contribute towards both the vascular and tissue pathology observed in diabetes.
Abstract 195: Survival in Out-of-Hospital Cardiac Arrest Patients Without a Prehospital Return of Spontaneous Circulation
Authors: Drennan Ian , Lin Steve , Sidalak Daniel , Morrison Laurie J
Published: April 2024

Background:
Survival rates are low in out-of-hospital cardiac arrest (OHCA) patients transported without a prehospital return of spontaneous circulation (ROSC). Few studies have examined the patient characteristics and prehospital factors associated with improved survival in this unique cohort.

Objective:
This study aims to describe patient and prehospital factors associated with survival to hospital discharge when patients fail to achieve ROSC in the field.

Methods:
This was a retrospective observational study of consecutive adult (≥18 years) OHCA patients without a prehospital ROSC from December 1, 2005 to March 30, 2012 who were attended to and transported by emergency medical services (EMS) from urban and rural regions employing the current termination of resuscitation (TOR) guidelines. EMS witnessed cardiac arrests, and cardiac arrests of non-cardiac etiology were excluded. Bivariate analyses were used to determine associations of patient characteristics and prehospital variables with survival to hospital discharge.

Results:
There were 17,488 OHCA treated by EMS, with 4,892 (28.0%) transported to hospital without a prehospital ROSC. Of these patients, only 42 (0.86%) survived to hospital discharge. Survivors were often younger with initial shockable rhythms, had OHCA that were more often witnessed by bystanders and occurred in public locations, compared to non-survivors (table). No differences were noted in the proportion of male gender, bystander CPR rates, EMS response time, advanced airway, or ALS provider level. Three patients (0.06%) did not meet the criteria for transport in accordance with current TOR guidelines however were transported at the discretion of EMS and survived.

Conclusion:
Less than 1% (the threshold for futility) of OHCA patients without a prehospital ROSC survived to hospital discharge. Survival in this cohort was associated with younger age, shockable initial rhythms, bystander-witnessed arrests, and public location.
Abstract 19504: Three Common Mental Status Scoring Systems are Predictive of Adverse Events in the Inpatient Setting
Authors: Robertson-Dick Brian J , Tien Linda , Churpek Matthew M , Yuen Trevor C , Edelson Dana P
Published: April 2024

Introduction:
Altered mental status has been shown to be one of the most accurate predictors of adverse events in hospitalized patients. Many early warning scores utilize the Alert-Verbal-Painful-Unresponsive (AVPU) scale to characterize mental status. The Glasgow Coma Scale (GCS) and Richmond Agitation-Sedation Scale (RASS) have both been validated in critically ill and trauma patients but are not well-characterized in the general inpatient ward population. We sought to compare GCS, RASS, and AVPU in their association with adverse outcomes in hospitalized ward patients.

Methods:
The nursing staff at the University of Chicago Medical Center began documenting GCS and RASS on adult ward patients once per 12-hour shift in August 2011. We conducted an electronic chart review of these hospitalizations up through February 2012. AVPU was abstracted from the eye subscale of the GCS. The primary outcome was the composite of ICU transfer, cardiac arrest, or mortality within 24 hours of an observation. Predictive accuracy was calculated and compared using the area under the receiver operating characteristic curve (AUROC).

Results:
A total of 107,944 paired observations were made in 11,383 patients, of which 757 experienced at least one adverse outcome. The raw data are shown in the figure. GCS, RASS and AVPU were highly correlated with each other (Spearman’s rho of 0.57 for GCS vs. AVPU, 0.26 for RASS vs. AVPU and 0.12 for GCS vs. RASS, p<0.001 for all three pair-wise comparisons). The AUROCs for AVPU, GCS, and RASS were 0.55 (95% CI: 0.54-0.56), 0.59 (95% CI: 0.58-0.60), and 0.60 (95% CI: 0.59-0.61), respectively. Simultaneous use of RASS and GCS produced an AUROC of 0.61 (95% CI: 0.60-0.63).

Conclusions:
GCS and RASS are both significantly better predictors of adverse events on the wards than the more commonly used AVPU scale, and may be worth collecting routinely in hospitalized ward patients. In addition, the combination of GCS and RASS may be more predictive than either alone.
Abstract 19506: The Role of Mir-16 on Endothelial Dysfunction in Rat with Atherosclerotic Diet with a Chronic Model of Femoral Artery Occlusion and Carotid Balloon Injury
Authors: Sorrentino Sabato , Polimeni Alberto , Iaconetti Claudio , Sabatino Jolanda , Gareri Clarice , Passafaro Francesco , Colangelo Maria , Covello Caterina , Caria Filomena , Carvelli Alessandra , Miceli Mariella , Giampà Salvatore , Curcio Antonio , De Rosa Salvatore , Indolfi Ciro
Published: April 2024

Background:
Peripheral artery disease (PAD) is associated to coronary endothelial dysfunction and is an important predictor of future cardiovascular events. MicroRNAs play a critical role in modulating a variety of cellular processes by post-transcriptional regulation of their target genes. They are highly expressed in human endothelial cells (ECs), playing key role in essential biological processes. Thus, the aim of the present study was to evaluate the role, if any, of miRNAs in endothelial dysfunction in a model of PAD.

Methods and Results:
Male Wistar rats were provided of a standard atherogenic, high cholesterol diet and divided into 4 groups: no treatment (sham); rat subjected to vascular injury by balloon catheter (B.I.); rats underwent common femoral artery ligation (PAD); rats subjected to common femoral artery ligation and, after 21 days, subject to balloon injury (PAD+B.I.). RNA from intima was separately obtained from carotid arteries and evaluated for endothelial specific miRNAs using a stem-loop real-time-PCR. Interestingly, among the most important miRNAs expressed, real time RT-PCR showed an important up-regulation of miR-16 in ECs extracted by injured carotid artery of PAD+BI group respect the ECs of the others groups. A bioinformatics approach revealed highly conserved binding sites for miR-16 in the 3’UTR of SMAD7, an inhibitor of TGF-β1 signaling. The expression level of SMAD7 was measured in ECs treated with antagomiR-16 using immunoblotting analysis. Up-regulation of miR-16 revealed a reduction of SMAD7 levels. Also, we evaluated the effects of miR-16 inhibition in ECs on mRNA and protein levels of eNOS and NF-kB, regulators of endothelial dysfunction. Real-time PCR showed an increased expression of eNOS mRNA in ECs treated with antagomiR-16. Furthermore, immunoblotting revealed increased eNOS protein production as well as its activation in ECs by miR-16 inhibition. Finally, we showed an increased NF-kB activation in ECs after up-regulation of miR-16.

Conclusions:
Our data demonstrated that in rat with PAD and atherosclerotic diet, miR-16 is up-regulated in endothelial cell of carotid arteries after balloon injury. This findings might of importance to assess future strategies in patients with PAD.
Abstract 19524: The Cardioprotective Phenotype in Mammalian Hibernators is Associated with Attenuation of Reperfusion-Induced Nuclear Factor-Kappa B Regulated Myocardial Inflammation
Authors: Podgoreanu Mihai V , Ma Qing , Zhang Zhiquan , Bain James , Newgard Christopher B , Riess Matthias , Barnes Brian M
Published: April 2024

Using an experimental model of surgical deep hypothermic circulatory arrest (DHCA), we hypothesized that hibernating arctic ground squirrels (AGS) display reduced myocardial injury following I/R compared to a non-hibernator (rat) through reduced NF-kB signaling and myocardial inflammation. We further explored the role of myocardial accumulation of ceramides, known regulators of NF-kB inflammatory signaling, in the hibernator cardioprotective phenotype.

Methods:
Euthermic AGS aroused from torpor and rats underwent DHCA (45min, with 3 or 24h reperfusion) or sham. We compared between species/time points by two-way ANOVA: 1) biochemical severity of myocardial injury (plasma HFABP, TnI, ELISA); 2) myocardial apoptosis (activated caspase-3, immunostaining; TUNEL); 3) myocardial NF-kB activation (transcription factor binding assay; nuclear translocation) 4) myocardial cytokine expression and leukocyte extravasation; 5) myocardial PPARa activity (ELISA); 6) myocardial levels of 12 ceramides (MS)

Results:
Compared to rats, AGS displayed robust ischemic tolerance following DHCA (Fig A). This was accompanied by reduced NF-kB DNA binding activity and nuclear translocation (Fig B), as well as decreased expression of downstream inflammatory cytokines. Significant post-I/R accumulation of 4 species of sphingoid base ceramides and 1 monohexosyl ceramide was found in rat vs AGS. Preservation of myocardial PPARa activity occurred in AGS, but was significantly downregulated in the rat (Fig B).

Conclusion:
We found an association between the hibernator cardioprotective phenotype and differences in myocardial activation of NF-kB inflammatory signaling. Mechanistically, this was associated with a) accumulation of several species of ceramides in rat vs AGS hearts, previously implicated in triggering mitochondrial dysfunction and apoptosis following I/R; and b) preservation of PPARa activity in AGS, with known dual metabolic anti-inflammatory effects.
Abstract 19538: Integrin-Linked Kinase Regulates Cardiomyocyte Calcium Signaling through Protein-Protein Interaction with Sarcoplasmic Reticulum Calcium ATPase
Authors: Li Mark , Traister Alexandra , Aafaqi Shabana , Lu Mingliang , Jiang Jiahua , Gross Gil , Hannigan Greg , Maynes Jason , Coles John
Published: April 2024

The transduction of mechanical load into dynamic changes in cardiac contractility is an incompletely understood process. ILK is a Ser/Thr kinase sarcomeric Z-disk protein with known mechanoreceptor function and cardioprotective properties. We hypothesized that ILK modulates calcium signaling in the cardiomyocyte to orchestrate both mechanoreceptor function and cytoprotection. ILK immunoprecipitates (IP) from transgenic mice with cardiac overexpression of ILK showed dose-dependent co-IP of sarcoplasmic reticulum calcium ATPase 2a (SERCA2a) confirmed by mass spectroscopy. Transduction of wild type ILK upregulated SERCA2a expression, and increased the phosphorylation (Thr17) of phospholamban, in human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). ILK knockdown by siRNA decreased SERCA2a expression. The upregulation of SERCA2a was not prevented by the ILK kinase small molecule inhibitor QLT0267 suggesting a scaffolding rather than catalytic effect of ILK. The beat rate response to the SERCA2a inhibitor thapsigargin (TG) in iPSC-CMs was determined by long-term measurements of electrical impedance using the xCELLigence RTCA Cardio System (Roche). ILK transduction resulted in a faster baseline beat rate compared to untreated and vector control cells (p < 0.01). TG significantly decreased beat rate with incomplete recovery after 30 hours (p < 0.01). TG also reduced beat rate in ILK-transduced cells; however, the recovery to pre-TG baseline was accelerated by the ILK transfection (time to recover 10 hr; p=0.017), consistent with increased ILK-mediated SERCA2a activity. Cardiomyocyte calcium transients were measured in human iPSC-CMs using confocal microscopy and analyzed using Origin 8.6. ILK-transduced iPSC-CMs showed a significantly reduced time constant Tau (p<0.01) and increased beat rate (p=0.01) compared to GFP-reporter control, consistent with SERCA2a-dependent increased rate of SR-mediated calcium uptake. We conclude that ILK regulates the expression and activity of SERCA2a in the cardiomyocyte. The demonstrated ILK-SERCA2a interaction provides an elegant mechanism for transduction of mechano- and stress- reception into dynamic, calcium-mediated changes in cardiomyocyte contractility.
Abstract 19544: Rate and Magnitude of Atrial Remodeling in Permanent Atrial Fibrillation
Authors: Luong Christina , Tsang Michael Y , Jue John , Gin Kenneth G , Nair Parvathy , Lee Pui-Kee , Barnes Marion E , Gao Min , Tsang Teresa S
Published: April 2024

Background:
Atrial fibrillation (AF) is associated with progressive enlargement of atrial size. Yet, the rate of change in left atrial (LA) and right atrial (RA) size is poorly defined.

Methods:
This cohort study included 51 patients with a history of permanent AF who had serial transthoracic echocardiograms performed between 2005 and 2010 at Vancouver General Hospital in British Columbia, a large university-based tertiary care hospital. Each had at least 3 transthoracic studies completed and had adequate views for assessment of LA and RA volume. Echocardiographic measurements were performed offline by one person using standardized methodology. Apical 4-chamber LA and RA volume by Simpson’s method was used for assessment of atrial size. Linear mixed effects modeling was used in analyzing changes over time.

Results:
Of the 51 subjects who underwent 183 studies in total, 28 were men (55%). The mean age at study entry was 72±10 yrs (47-85 yrs). The mean follow-up time was 3.2±2.9 years. The findings for the first 3 consecutive studies for these patients are shown in the attached table. There was a significant increase in LA and RA volume; the increases were 2.98 mL/m2 per year (95% CI 1.23-4.73, P<0.0001) and 1.25 mL/m2 per year (95% CI 1.01-1.61, P<0.0001) respectively. In parsimonious models adjusting for age, sex, and length of follow-up, left ventricular ejection fraction of less than 50% at first study was associated with a significantly more rapid increase in LA volume over time (P<0.001).

Conclusion:
Both LA and RA volume increased over time in patients with permanent AF. The absolute magnitude of increase appeared greater, and the rate of change faster, for LA than RA volume. Further studies are needed to determine the factors that mediate these changes and their reversibility.
Abstract 19569: Inhibition of Cardiac Actin-Myosin Interaction by Blebbistatin Delays Onset of Ventricular Fibrillation during Myocardial Ischemia
Authors: Hatcher Amanda S , Clements-Jewery Hugh
Published: April 2024

Sudden cardiac death in the context of coronary heart disease is most commonly the result of the occurrence of ventricular fibrillation (VF) following a new episode of myocardial ischemia. The electrophysiological disturbances that create a substrate for the development of VF in myocardial ischemia can be traced back to depletion of cellular ATP resulting from ATP consumption outstripping supply. Reducing cardiac ATP consumption may thus delay or inhibit the development of VF in ischemia. Therefore, we determined the effect of blebbistatin, a selective inhibitor of contraction that will reduce ATP consumption via reducing cardiac work, on the incidence and time of onset of ventricular fibrillation (VF) in an established model of regional myocardial ischemia. Isolated male rat hearts (n=12 per group) were randomized to one of 4 groups: control (vehicle 0.01% v/v), 0.1µM blebbistatin, 1µM blebbistatin, or 10µM blebbistatin. The ECG and left ventricular developed pressure (LVDP) were recorded in each heart. Hearts were perfused with test solution for 15 min, after which regional myocardial ischemia was induced by tightening a snare occluder placed around the left main coronary artery. Ischemia was maintained for 30 min. As expected, prior to myocardial ischemia, blebbistatin reduced LVDP (p>0.05 vs control), abolishing it at the 1µM and 10µM concentrations. Compared to control, the incidence of VF during ischemia was not affected at blebbistatin concentrations of 0.1µM and 1µM (83% and 92% respectively vs 83% in controls) and was reduced only as a trend with 10µM blebbistatin (67%; p<0.05). However, there was a concentration-dependent prolongation in the mean time to onset of VF with blebbistatin, which was significantly longer than the mean time to VF onset in controls at a concentration of 10µM (1367±113s vs 924±80s; p<0.05). This effect of blebbistatin was associated with a trend to increased ATP content in myocardial tissue samples taken from the ischemic zone as measured by luciferase luminescence assay. In conclusion, a reduction in cardiac work by inhibition of the cardiac contractile machinery can delay the onset of VF during myocardial ischemia, most likely as a consequence of delaying the depletion of myocardial ATP.
Abstract 19571: Atrial Septal Interventions After Ductal Stenting and Bilateral Pulmonary Artery Banding
Authors: Wan Andrea , Lee Kyong-Jin , Benson Lee , Caldarone Christopher , Chaturvedi Rajiv R
Published: April 2024

Introduction
Bilateral pulmonary artery banding with arterial duct stenting (H1) leaves the state of the atrial septum unresolved. Atrial communications can become restrictive and their management is an important problem. We reviewed our experience of atrial septal interventions (ASI) in H1 patients until their second stage procedure (H2).

Methods and Results
A retrospective analysis of the first 66 H1 patients between 2004 and 2011. Thirty-nine (59%) of these patients had hypoplastic left heart syndrome. 34/66 (52%) patients required 42 ASI. These were performed before (n=4), during (n=5) or after H1 (n=25). An ASI was frequently required for neonates on a path to a Fontan (29/48, 60%) or being bridged to transplantation (4/10, 40%), but was rare for borderline LV (1/8, 13%). An ASI was required if there was a small ASD on the initial echocardiogram (p<0.01). A variety of percutaneous techniques were used: balloon septostomy/septoplasty (including cutting balloons), stenting and radio-frequency perforation of the atrial septum. Directly measured trans-septal mean gradient decreased from 12mmHg (range 2-25 mmHg) to 1mmHg (range 0-10mmHg). There were three ASI related deaths and 6 major complications. Three patients with LV sinusoids/fistulae experienced acute myocardial ischaemia following ASI. ASI was associated with an increased risk of death prior to H2.

Conclusion
Catheter techniques can produce minimally restrictive atrial communications, but can be associated with post-procedural instability. In patients with coronary sinusoids, myocardial ischaemia may occur if there is a large increase in pulmonary blood flow.
Abstract 19577: Diminazene Aceturate Inhibits Apoptotic Cell Death to Protect from Pulmonary Fibrosis and Associated Pulmonary Hypertension
Authors: Shenoy Vinayak , Qi Yanfei , Gupta Dipankar , Katovich Michael , Raizada Mohan
Published: April 2024

INTRODUCTION:
Studies have demonstrated that Angiotensin-converting enzyme2 (ACE2) plays a protective role against lung fibrosis. In this study, we evaluated the pharmacological actions of a recently identified synthetic activator of ACE2, Diminazene aceturate (DIZE) in the bleomycin model of pulmonary fibrosis (PF).

METHODS:
PF was induced by a single intratracheal instillation of bleomycin (Bleo, 5U/Kg) in 8 weeks old male Sprague-Dawley rats. Rats were randomized into three groups; Control, Bleo and Bleo+DIZE. DIZE treatment (15mg/Kg, sc) was commenced at the same time as bleomycin administration. After 2-weeks of bleomycin instillation, rats were instrumented to measure right ventricular systolic pressure (RVSP), followed by heart and lung excision to examine cardio-pulmonary remodeling and apoptosis.

RESULTS:
Bleomycin administration resulted in significant elevation of right ventricular systolic pressure (RVSP; Control: 26+1mmHg; Bleo: 41+2mmHg), signifying development of pulmonary hypertension. In addition, these animals exhibited maladaptive cardiac remodeling in terms of increased myocardial fibrosis (%Fibrosis; Control: 6+0.23; Bleo: 17+0.3) and right ventricular hypertrophy (RVH; Control: 0.26+0.007; Bleo: 0.40+0.03). Co-administration of DIZE significantly attenuated all these parameters (RVSP; 32+0.5mmHg; RVH; 0.30+0.01 and %Fibrosis; 7.2+0.6). A higher Ashcroft score was observed in bleomycin-challenged animals, signifying development of PF, which was prevented by DIZE treatment (Control: 1.2+0.09; Bleo: 6.5+0.06; Bleo+DIZE: 2.8+0.03). The protective effects of DIZE were associated with favorable modulation of the pulmonary renin angiotensin system and decreased pro-inflammatory cytokines. Furthermore, lung sections of bleomycin administered animals showed increased TUNEL staining for apoptosis, which was prevented by DIZE treatment (TUNEL positive index; Con: 0.03+0.005; Bleo: 0.2+0.04; Bleo+DIZE: 0.07+0.003).

CONCLUSION:
Our studies show that DIZE, an ACE2 activator attenuates bleomycin-induced lung fibrosis and associated cardio-pulmonary pathology, indicating a therapeutic potential of this drug in PF therapy .
Abstract 19582: Deletion of miRNA-146a Alters Host Immune Response to Coxsackievirus B3 with Activation of NK cells
Authors: Narezkina Anna , Lim Byung-Kwan , Grivennikov Sergei , Boldin Mark , Taganov Konstantin , Baltimore David , Knowlton Kirk U
Published: April 2024

Coxsackievirus B3 (CVB3) is a positive single-stranded RNA virus that causes a range of diseases, including myocarditis, hepatitis, and pancreatitis. Understanding complex interplay between the virus and host immune system will provide insight for development of future therapeutic interventions. miRNA-146a plays a role in immune system through regulation of NF-kB signaling. It is expressed at relatively high levels in hematopoetic cells, and upregulated with various immune stimuli. We hypothesized that miRNA-146a is involved in mediating immune response against CVB3 infection. Genetically modified C57BL/6 mice with global deletion of miRNA-146a, and wild type littermate controls were intraperitoneally injected with 10
3
-10
4
PFU of CVB3. miRNA-146a null mice had significantly higher mortality rate, reaching 45% by day 4 after infection (n=16), compared to zero mortality observed in wild type mice (n=13, p=0.006). Evans blue dye uptake was higher in the hearts of knock out animals 4 days post-infection, indicating disruption of cardiomyocyte membrane integrity. The degree of hepatocyte damage and disruption of the lobular architecture in liver was more pronounced in the miRNA-146a null mice 4 days post-infection. In normal uninfected state the majority of NK cells are localized in liver and spleen, and they are one of the first to get activated in CVB3 infection. We assessed the degree of NK cell activation 24 hours post infection with FACS analyses of mononuclear cells isolated from liver by Percoll gradient. The total percentage of NK cell population in liver was the same between both groups. On average 10+/-0.8% of total NK population in the livers of knock out mice were represented by the cells with high level of TNF-related apoptosis-inducing ligand (TRAIL) expression, whereas only 4.7+/-2% of the hepatic NK cells in the wild type controls had the same level of TRAIL expression (n=3, p=0.03). Liver mRNA levels of Granzymes A and B, and perforin were 4- to 8-fold higher in miRNA-146a null mice compared to wild type controls (n=6 for wild type, n=5 for knock out, p0.05). Taken together, these data indicate that deletion of miRNA-146a alters host response to CVB3 by increasing NK cell activation.
Abstract 19598: Evaluation of Left Ventricle Function and Oxidative Metabolism in Large Animal Model of Chronic Heart Failure
Authors: Tarkia Miikka , Haavisto Matti , Stark Christoffer , Vähäsilta Tommi , Savunen Timo , Strandberg Marjatta , Lepomäki Virva , Pietilä Mikko , Saukko Pekka , Roivainen Anne , Saraste Antti , Knuuti Juhani
Published: April 2024

Background and aims:
Large animal model of chronic heart failure (HF) has been difficult to produce. Recently described pig model ofsurgical 2 step occlusion of the left anterior descending (LAD) coronary artery with distal ligation and proximal ameroid constrictor resulted in large anterior myocardial infarct (MI) with reasonable good survival (approx. 75% of animals alive at three months). We wanted to study by echocardiography and positron emission tomography (PET) the effects of proximal ligation of LAD in pig on LV remodelling and oxygen consumption during 3 months of follow-up.

Methods:
Male farm pigs ageing 3 weeks had either sham operation (control, n=4) or LAD occlusion (HF, n=8). Three months later, LV volumes (Modified Simpsons cylinder formula) were measured by transthoracic echocardiography (TTE). Myocardial kinetics k
1
and mono-exponential clearance rate of
11
C-acetate K
mono
were measured with PET to assess myocardial perfusion and oxidative metabolism, respectively.

Results:
None of the controls had MI, whereas seven of eight animals in the HF group had anterior MI scar as confirmed by TTC staining. PET perfusion showed average MI size of 26 ± 17 % of the LV in HF pigs. Echocardiography showed larger LV diastolic and systolic volumes in HF pigs than sham-operated pigs (diastolic volume 302±116 vs.109±28 ml, p=0.03; systolic 202±108 vs. 52±16 ml, p=0.05), whereas EF was lower (37±12 vs. 53±5 %, p=0.03). In the remote non-infarcted myocardium, perfusion and oxygen consumption was lower in HF than control pigs (k
1
0.78±0.13 vs. 1.26±0.41 ml/g/min p=0.01, K
mono
0.114±0.024 vs. 0.146±0.008 min
-1
, p=0.03).

Conclusions:
Surgical 2 step occlusion of the left anterior descending (LAD) coronary artery in pigs resulted in large area of myocardial infarction, reduced systolic function and LV remodelling. Consistent with HF, myocardial perfusion and oxygen consumption was reduced. Effects of therapeutic interventions on myocardial perfusion and oxygen consumption can be monitored in this model of chronic HF.
Abstract 19635: Glutathione-S-Transferase P Regulates Endothelial Progenitor Cell (EPC) Function in a c-Jun N-terminal kinase(JNK)-Dependent Manner and Enhances Neovascularization in Post-Infarction Heart Failure
Authors: Zhou Guihua , Hamid Tariq , Mohamed Ismahil Mohamed Ameen , Prabhu Sumanth D
Published: April 2024

Glutathione-S-transferase P (GSTP), via non-catalytic inhibition of JNK, modulates proliferation of bone marrow (BM) myeloid progenitors; however, its effects on EPCs are unknown. We hypothesized that GSTP supports normal EPC function via JNK suppression in BM-derived cells, and thereby promotes neovascularization in heart failure (HF). EPCs (CD34+VEGFR2+) and activated monocytes (F4/80+CD11b+) in BM and peripheral blood (PB) were determined by flow cytometry in wild type (WT) and GSTP-/- mice. Compared with WT, GSTP-/- mice exhibited significantly (p<0.01) reduced EPC number in PB (0.13±0.03 vs 0.21±0.07%) and BM (1.0±0.2 vs 1.7±0.6%), and increased activated monocytes, despite augmented numbers of CD34+CD45+ BM hematopoietic stem cells (HSCs; 6.7±0.8 vs 5.8±0.44%). PB EPCs in GSTP-/- mice were restored (p<0.05) with 5 days treatment in vivo with the specific JNK inhibitor, SP600125 (0.26±0.05% vs 0.15±0.04% before SP60025), whereas circulating activated monocytes were significantly reduced. Compared with WT, GSTP-/- BM-derived mononuclear cells cultured in endothelial growth medium for 10 d demonstrated reduced EPC colonies, less EPC migration in Transwell plates (VEGF gradient), and diminished vascular tube formation, indicating that GSTP deficiency decreased EPC differentiation from BM progenitors and EPC functional characteristics. All of these parameters were restored upon concomitant treatment with SP600125, and JNK phosphorylation, which was augmented in GSTP-/- BM, was significantly decreased by SP600125, suggesting JNK dependence of the GSTP-mediated effects on EPCs. Furthermore, EPCs, monocytes, and cardiac remodeling were examined WT and GSTP-/- mice with HF induced by left coronary ligation. As compared with WT, GSTP-/- HF mice exhibited (p<0.05): 1) fewer circulating PB EPCs and increased activated monocytes; 2) increased BM-HSCs but reduced BM EPCs; and 3) exaggerated pathological remodeling, augmented inflammation, and reduced capillary density and neovascularization in failing hearts. We conclude that GSTP promotes EPC function, mediated by inhibition of JNK in BM-derived progenitor cells, and also suppresses inflammation, and thereby imparts cardioprotective benefits in the post-infarct failing heart.
Abstract 19642: Correlation between Diabetes Control and Diastolic Dysfunction
Authors: Sharif Roozbeh , Khalife Wissam I , Morsy Mohammad A , Khan Adnan , Mutnuri Sangeeta , Kohli Anjali
Published: April 2024

Background:
The association of diabetes mellitus (DM) and left ventricular diastolic dysfunction (DD) has been well established. Objective: We aimed to investigate whether better serum glucose control is associated with lower risk of developing DD in diabetic patients.

Methods:
In this observational retrospective study, we reviewed the echocardiographic results of patients who presented to ambulatory clinics of a tertiary academic medical center. Study population included 1329 DD patients with LVEF>50% and 308 randomly selected normal controls. Demographic, clinical variables and serum hemoglobin A1c (Hb A1c) level were compared between DD patients and normal controls. The same comparison was conducted between patients with impaired relaxation (grade I) and those with pseudonormal (grade II) or restrictive (grade III). Serum A1c was considered as the surrogate of diabetic control. We used logistic regression analysis to examine the association of DM control with DD and its severity, after adjusting for potential confounders.

Results:
Overall 51.8% of the participants were females. Among 1329 patients with DD 1238 (93.2%) had grade I and 91 (6.8%) had grade II (or higher). DM was reported in 19% of DD patients and 20.1% of normal controls (p=0.0953). However, serum HbA1c was higher among DD patients, compared to normal controls (7.5 vs. 6.4, p=0.005). Multivariable analysis indicated that after adjusting for age, sex, estimated glomerular filtration rate, and history of hypertension, higher serum HbA1c level is an independent correlate of DD (odds ratio: 1.4, 95%CI: 1.1, 1.7, p=0.006). Furthermore, comparison of DM prevalence and serum HbA1c level between grade I DD patients with grade II (or higher) was not statistically significant.

Conclusion:
The results of this study demonstrated the possible role of better DM control in prevention of DD in diabetic patients. Further studies are encouraged on potential mechanistic pathway that can alleviate diabetes-induced left ventricle dysfunction.
Abstract 19686: Nox4-Dependent Increase in Mitochondrial Reactive Oxygen Species Levels Contributes to Aging-Associated Increase in Cardiovascular Disease
Authors: Vendrov Aleksandr E , Madamanchi Nageswara R , Runge Marschall S
Published: April 2024

The incidence of cardiovascular diseases (CVD) increases with age. Elevated ROS levels and resulting vascular inflammation were implicated in this process. We previously reported that inhibition of Nox1/Nox2 NADPH oxidases in p47phox deficient apoE-/- mice was not sufficient to reduce aging-associated increase in vascular reactive oxygen species (ROS) levels and atherosclerosis, aortic stiffness and cardiac dysfunction. This loss of protection is associated with increased total as well as mitochondrial ROS (mtROS) levels in the vasculature of aged apoE-/- and apoE-/-/p47phox-/- mice. Here we investigated the mechanisms and impact of aging-associated increase in oxidative stress in mouse and human CVD. Vascular smooth muscle cells (VSMC) isolated from aged wild-type and p47phox-/- mice had higher total and mtROS levels compared to VSMC from respective young mice (p<0.01 for both total and mtROS). Nox4 expression was increased in the aortic wall of aged apoE-/- and apoE-/-/p47phox-/- mice and in mitochondria of VSMC from both aged mice (p<0.05). Nox4 knockdown with shRNA resulted in decreased mtROS levels in aged wild-type VSMC (p<0.05). Increased oxidation and dysfunction of mitochondrial proteins were observed in VSMC from aged mice. Vcam1 expression, which was increased in the aged VSMC was abrogated on treatment with MitoTEMPO, a mitochondria targeted antioxidant (p<0.05). Increased mtROS levels in aortic VSMC from aged subjects were associated with enhanced mitochondrial Nox4 expression. Expression of Nox4 in the human carotid artery wall correlated with subjects’ age (r2 = 0.59, p<0.0001) and atherosclerotic lesion complexity (p< 0.0001). In addition, a significant association was observed between mitochondrial DNA damage index and CVD (r=0.45, p=0.013). In conclusion, Nox4-dependent increase in mitochondrial oxidative stress may contribute to mitochondrial DNA damage, mitochondrial dysfunction, vascular inflammation and increased incidence of CVD in aging, suggesting that selective targeting of mtROS in aging is beneficial.
Abstract 19711: Mitochondria-Targeted Antioxidant Therapy Prevents Connexin43 Remodeling and Sudden Death Caused by Renin-Angiotensin System Activation
Authors: Sovari Ali A , Rutledge Cody A , Jeong Euy-Myoung , Dolmatova Elena , Arasu Divya , Liu Hong , Vahdani Nooshin , Gu Lianzhi , Bonini Marcelo G , Duffy Heather S
Published: April 2024

Introduction:
Previously, we showed a mouse model (ACE8/8) of cardiac renin-angiotensin system (RAS) activation has a high rate of spontaneous ventricular tachycardia (VT) and sudden cardiac death (SCD) secondary to a reduction in connexin43 (Cx43) level. Angiotensin-II activation increases reactive oxygen species (ROS) production, and these mice show cardiac oxidation. We sought to determine the source of ROS and if ROS played a role in the arrhythmogenesis.

Methods and Results:
Wild-type and ACE8/8 mice with and without two weeks of treatment with L-NIO (nitric oxide synthase inhibitor), sepiapterin (precursor of tetrahydrobiopterin), MitoTEMPO (mitochondria-targeted antioxidant), TEMPOL (a general antioxidant), apocynin (NADPH oxidase inhibitor), allopurinol (xanthine oxidase inhibitor), and ACE8/8 crossed with P67 dominant negative mice to inhibit the NADPH oxidase were studied. Western blotting, detection of mitochondrial ROS by MitoSOX Red, electron microscopy, immunohistochemistry, fluorescent dye diffusion technique for functional assessment of Cx43, and in-vivo electrophysiology study were performed. Treatment with MitoTEMPO reduced SCD in ACE8/8 mice (from 74% to 18%, P=0.0005), decreased VT inducibility (from 90% to 17%, P<0.05), diminished elevated mitochondrial ROS to the control level, prevented structural damage to mitochondria, resulted in 2.6 fold increase in Cx43 level at the gap junctions, and corrected gap junction conduction. None of the other antioxidant therapies prevented VT and SCD in ACE8/8 mice.

Conclusion:
Mitochondrial oxidative stress plays a central role in angiotensin II-induced gap junction remodeling and arrhythmia. Mitochondria-targeted antioxidants may be effective antiarrhythmic drugs in cases of RAS activation.