bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 20140: Minibrain Relate Kinase / Dyrk1B Links Skeletal Muscle Glycolytic Metabolism with Insulin Resistance and Causes Metabolic Syndrome
Authors: Fathzadeh Mohsen , Keramati Ali Reza , Go Gwang , Singh Rajvir , Sarajzadeh Kazem , Tavakkoly-Bazzaz Javad , Noorafshan Ali , Kasaei Mohammad , Amini Masoud , Omrani Gholam Hossein R , Babaee Bigi Mohammad Ali , Babaei Masoud , Hosseinian Adalat , Malekzadeh Reza , Lifton Richard , Mani Arya
Published: July 2021

We have identified a novel nonconservative mutation in Minibrain related serine/threonine kinase (Mirk/ Dyrk1B) in outlier kindreds with metabolic syndrome. The mutation substitutes cysteine for arginine (R102C) and segregates with most traits of metabolic syndrome, including central obesity, diabetes and hypertension. Oral glucose tolerance test (OGTT) in young nondiabetic mutation carriers revealed insulin resistance compared to noncarrier family members. Since skeletal muscle (SM) is the largest organ for glucose uptake and metabolism, we obtained Vastus Lateralis biopsies of mutation carriers and their unaffected relatives and examined them for gene/protein expression by deep RNA sequencing (RNA-Seq) and Western blot analysis and for fiber composition by immunostaining. The fiber composition data demonstrated fewer slow-twitch fibers (35% vs. 75%) and more fast -twitch fibers (65% vs. 25%) in SM of mutation carriers vs. controls. Interestingly, there were increased protein expression levels of fast-twitch fiber type proteins (MYH11, MYLPF), pyruvate dehydrogenase kinase, pyruvate kinase, and neuronal nitric oxide synthase in SM of mutation carriers vs. noncarriers. Consistent with these findings, the protein expression levels of the master regulator of cellular energy metabolism mitochondrial biogenesis, PPAR-gamma coactivator (PGC-1a), were reduced and the nuclear expression levels of FOXO1 and NFAT were increased. Similar findings were observed when wildtype and mutant (R102C) Dyrk1B were overexpressed in C2C12 cells. The overexpression of the kinase deficient Dyrk1B (Y271/273F) similarly resulted in reduced expression of PGC-1a and increased expression of nuclear FOXO1, suggesting kinase independent effects. Taken together, these findings suggest that enhanced kinase-independent activities of Dyrk1B, either through increased expression or by its gain of function mutation R102C induce insulin resistance by promoting glycolytic metabolism and reducing oxidative phosphorylation. In conclusion, Dyrk1B is a potential target for development of novel drugs that aim to enhance skeletal muscle insulin sensitivity.
Abstract 20188: The Effect of Disclosing Genetic Risk for Coronary Heart Disease on Perceived Personal Control and Genetic Counseling Satisfaction: The MI-GENES Study
Authors: Robinson Christopher L , Jouni Hayan , Kruisselbrink Teresa M , Christensen Kurt D , Green Robert C , Kullo Iftikhar J
Published: July 2021

Background:
Perceived personal control (PPC) represents the belief that a person can alter his/her own situation or state. Higher PPC has been associated with increased health-related quality of life and helps facilitate healthy behavioral changes. We investigated whether disclosure of coronary heart disease (CHD) genetic risk influences PPC and genetic counseling satisfaction (GCS) in the myocardial infarction genes (MI-GENES) study, a randomized controlled trial of disclosing genetic risk of CHD.

Methods:
Participants (40-65 year-old, at intermediate 10-year CHD risk, and not on statins) were randomized to receive estimated 10-year risk of CHD based on their Framingham Risk Score (FRS) or FRS plus a 28 SNP genetic risk score (FRS*GRS). CHD risk was disclosed in each arm by a genetic counselor during a 30-minute scripted session that included a discussion of the impact of family history on CHD risk. For FRS*GRS participants, the genetic counselor also reviewed how their genetic risk score altered their FRS. Each participant then met with a physician to engage in shared-decision making regarding the need for statin therapy. Afterwards, study participants were asked to complete validated surveys to assess PPC and GCS. The 9-item PPC questionnaire was scored 0-9, with higher scores indicating greater control beliefs. The 5-item GCS questionnaire was scored 0-10, with greater scores indicating greater satisfaction with the disclosure session.

Results:
207 patients (mean age 58.8±5 years, 46.7% males) were randomized to receive either FRS or FRS*GRS. Patients randomized to receive FRS*GRS had higher PPC compared to FRS although the absolute difference was small (8.85±0.77 vs. 8.54±1.31, P=0.016). Patients randomized to receive FRS*GRS also had a higher GCS score than FRS patients (9.08±2.67 vs. 8.3±3.67, P=0.050].

Conclusions:
Disclosure of genetic risk for CHD did not adversely affect PPC or GCS. In fact, patients who received CHD genetic risk information had higher PPC and GCS. Our findings suggest that disclosure of CHD genetic risk is appreciated by patients and may empower them to improve health-related behaviors.
Abstract 20189: Renal Denervation With Neuron Targeted Nanoparticles Attenuates the Hypertension Associated With Obesity
Authors: Yu Lilei , Zhou XiaoYa , Wang Songyun , Wang Zhuo , Huang Bing , Liao Kai , Jiang Hong
Published: July 2021

Introduction:
Obesity is associated with hypertension and increased renal sympathetic nervous activity, Our recent study indicated that autonomic denervation could be induced by nanoparticles.In addition, non-toxic fragment of tetanus toxin, known as tetanus toxin C fragment(TTC), which demonstrates extremely high affinity binding to the surfaces of neurons.

Hypothesis:
This study was to test the hypothesis that renal denervation with TTC-conjugated nanoparticles could attenuate hypertension associated with obesity .

Methods:
TTC-conjugated nanoparticles and neurotoxic agent (N-isopropylacrylamide monomer) were synthesized. We determined the hemodynamic responses to a high-fat diet in control (n = 6) and renal-denervated by nanoparticles (n = 8) chronically instrumented dogs. After a control period of 7 days, dogs were placed on a high-fat diet for 5 weeks. a modified balloon catheter will be advanced in the target renal artery segment to allow nanoparticles permeating into vascular wall, after that the moving of nanoparticles will be guided by outside magnetic filed towards renal sympathetic nerve.Blood pressure(BP),heart rate variability (HRV),serum norepinephrine (NE) were measured. Pathological examinations were performed on all retrieved samples.

Results:
In response to a high-fat diet, body weight increased from 17.6 ± 2.4 to 24.8 ± 1.8 kg in the control group. Heart rate increased from 92 ± 6 to 118 ± 10 beats per minute in the control group. BP increased significantly from 105 ± 5 to 139 ± 4 mm Hg in the control group. In contrast, 5 weeks of a high-fat diet in the renal denervation group did not significantly increase body weight(which went from 18.3 ± 2.5 to 19 ± 2.1 mm Hg), Heart rate (which went from 87 ± 3 to 89 ± 6 mm Hg) and BP (which went from 107 ± 3 to 109 ± 6 mm Hg). sympathetic indices of HRV, serum NE, renal sympathetic activity and the expression of c-fos protein in renal sympathetic nerve was significantly lower in the renal denervation group. A histological examination revealed the disruption of nerve fibers, necrosis of Schwann cells and neurons, and apparent denervation in denervation group.

Conclusions:
Our results indicate that Renal denervation by TTC-conjugated nanoparticles could attenuate hypertension associated with obesity.
Abstract 20219: Foxc2 Plays a Key Role in the Early Response to Cardiac Ischemia via Regulation of Cardiomyocyte Apoptosis
Authors: Dietz William H , Shim Kyoo , Koo Hyun-Young , Liu Ting , Kamide Christine , Kume Tsutomu
Published: July 2021

Introduction:
We have previously shown that forkhead box transcription factor C2 (Foxc2) plays a crucial role in angiogenesis. While Foxc2 has been implicated in cardiovascular disease, its role in the adult heart under pathological conditions and its underlying mechanism remain poorly understood.

Hypothesis:
We hypothesized that, in response to ischemic injury, Foxc2 acts through a cell-type-specific regulation of apoptosis.

Methods:
To test this hypothesis, mice heterozygous for either the Foxc2 global knockout (Foxc2+/-) or endothelial specific knockout (EC-Foxc2+/-), along with litter-mate controls, were subjected to myocardial infarction (MI) followed by echocardiographic analysis or whole-heart perfusion and harvest at baseline, or days 1, 3, 7, 14, or 28 post-MI. Hearts were then processed for histological staining, digested for flow cytometry, or further dissected for expression analysis.

Results/ Conclusion:
Time-course analysis of wild-type mice following MI revealed elevated border-zone Foxc2 mRNA 1 day post-MI, peaking at 3 days, and remaining highly elevated through day 7. Global Foxc2+/- mice subjected to ischemic injury displayed increased fibrotic scar tissue and impairment of cardiac function growing more significant with time, while EC-Foxc2+/- mice showed no change as measured by echocardiography and Masson’s Trichrome stain. Dual staining of TUNEL and lectin revealed increased border-zone apoptosis in global Foxc2+/- mice but no change in neovascularization. Analytical flow cytometry showed no difference in endothelial-specific apoptosis or cardiac leukocyte recruitment in global Foxc2+/- mice. Investigation of day 3 border-zone mRNA levels showed up-regulation of several pro-apoptotic genes including p53 and caspase3 in global Foxc2+/- hearts. Additionally, TUNEL and desmin co-staining confirmed a significant increase in cardiomyocyte-specific apoptosis 3 days post-MI. Our findings document that, in the early response to ischemic insult, Foxc2 acts through regulation of cardiomyocyte survival but not regulation of endothelial cell survival or leukocyte recruitment. Further investigation is warranted to elucidate the exact link between the protective effects of Foxc2 and cardiomyocyte survival.
Abstract 20340: Defect of Ca
2+
-activated Cl
-
Channel in Intestinal Nodose Neurons Contributes to Impaired Satiety Signal in High-Fat Diet Induced Obesity
Authors: Wang Runping , Lu Yongjun , Cicha Michael Z , Rahmouni Kamal , Chapleau Mark W , Benson Christopher J , Abboud François M
Published: July 2021

High fat diet inhibits the cholecystokinin (CCK) induced satiety signal in vagal afferents, which may contribute to the associated increased food intake. We hypothesized that a defect of Ca
2+
-activated chloride channel (CaCC) in high fat (HFD) fed mice leads to the reduction of CCK responses in intestinal vagal afferent nodose neurons. By using the whole cell patch-clamp in cultured nodose ganglia neurons isolated from C57BL/6 mice, we found that CCK (10nM) induced large inward chloride (Cl
-
) currents (36.0±11pA/pF) that were eliminated with the fast Ca
2+
chelator BAPTA (1.0±0.5pA/pF, n=7), and reduced significantly by the CaCC channel inhibitor niflumic acid (100 μM, 13.6±2.0pA/pF, p<0.05, n=8). The response to CCK in DiI-labeled proximal intestinal nodose neurons from obese mice fed a 60% HFD for 10 weeks was reduced significantly (6.1±2.9pA/pF, n=7, p<0.01) relative to control lean mice (24.8±4.9pA/pF, n=7). The underlying molecular mechanism of the reduced CCK response in mice fed a HFD did not involve altered expression of CCK receptors in nodose neurons. We found that the relative mRNA (qPCR) of CCK receptor B was not significantly changed (1.01±0.13 in control vs. 1.18±0.31 in HFD nodose ganglia, n=4, p>0.05) and the mRNA of CCK receptor A was even increased from 1.06±0.37 in control to 1.54±0.41 in HFD ganglia (n=4, p<0.05). In contrast, the CaCC channel mRNA (Ano I) was decreased to 0.61±0.09 relative to 1.01±0.20 (n=4, p<0.001), and Ano II mRNA was decreased to 0.31±0.07 relative to 1.02±0.22 (n=4, p<0.001) in nodose ganglia from HFD fed vs. control lean mice. Since the maximum current induced by a saturation level of ligand reflects the level of protein expressed on the cytoplasmic membrane, we tested the CaCC current induced by a high level of intracellular Ca
2+
(20μM). We found that the maximum current was smaller in DiI labeled intestinal nodose neurons from HFD fed mice (13.7±2.9 pA/pF vs. 26.9±3.6 pA/pF in control mice, n=10, p<0.05).

Our results indicate that CCK-activated currents recorded from intestinal vagal afferent nodose neurons are reduced in mice fed a HFD, and are associated with reduced expression of a CCK-activated Ca
2+
-dependent Cl
-
channel. This mechanism may contribute significantly to HFD-induced suppression of the satiety reflex.
Abstract 20347: Does Electrophysiological Toxicity Limit the Therapeutic Window of Serca2a Gene Therapy?
Authors: Xie Chaoqin , Hu Jun , Jeong Dongtak , Kohlbrenner Erik , Hajjar Roger J , Akar Fadi G
Published: July 2021

Rescue of SERCA2a expression by gene transfer to the endstage failing heart improves its mechanical and electrophysiological (EP) function. However the safety profile of SERCA2a gene therapy as a preventive measure in patients at early stages of remodeling prior to SERCA2a downregulation is unknown. Examination of the EP consequences of SERCA2a gene therapy in non-failing hearts is imperative in determining its potential EP toxicity.

Hypothesis:
SERCA2a upregulation using high titer adeno associated virus type 9 (AAV9) mediated gene transfer to normal rats may promote arrhythmogenic triggers, thereby limiting the therapeutic window for this approach.

Methods:
Using high resolution optical action potential (AP) imaging, we investigated the EP substrate 6 weeks post gene transfer of 5E11 AAV9.SERCA2a (N=13) or AAV9.GFP (N=6) to normal rats. Arrhythmia susceptibility was determined under conditions that promoted Ca overload by burst pacing & ischemia reperfusion (IR) injury.

Results:
AAV9.SERCA2a hearts exhibited a 50% increase in SERCA2a expression at the mRNA and protein levels compared to AAV9.GFP. No differences in heart weight to body weight were found between groups (3.85 vs 3.74 mg/g). During baseline perfusion, AAV9.GFP hearts exhibited significantly prolonged (by 30%, p<0.05) AP durations (APD) and a strong trend (p=0.07) towards greater APD heterogeneity. Challenge with rapid pacing resulted in the onset of sustained VF in 4/6 AAV9.GFP and 0/13 AAV9.SERCA2a hearts (p=0.004). Despite significant SERCA2a upregulation, APD and conduction velocity were identical in AAV9.SERCA2a compared to normal hearts indicating lack of EP toxicity. During prolonged low flow ischemia, AAV9.SERCA2a hearts exhibited a trend towards higher incidence of arrhythmias compared to normal hearts, but differences were not statistically significant (p=0.08). Finally, all AAV9.SERCA2a hearts exhibited rapid recovery of APD and excitability upon reperfusion following 10 min of no flow ischemia.

Conclusions:
High titer gene transfer of AAV9.GFP but not AAV9.SERCA2a elicits adverse EP remodeling in normal rat myocardium. The lack of an EP phenotype of AAV9.SERCA2a despite 50% upregulation in SERCA2a levels is consistent with a wide safety margin for this therapy.
Abstract 20360: MRI Assessment of Diastolic and Systolic Intraventricular Pressure Gradients in Heart Failure
Authors: Londoño Francisco J , Segers Patrick , Shiva kumar Prithvi , Konda Prasad , Zamani Payman , Bhuva Rushik , Dunde Anjaneyulu , Ferrari Victor , Chirinos Julio A
Published: July 2021

Background:
Non-invasive assessment of left ventricular (LV) diastolic function is an important goal to better understand physiologic abnormalities in heart failure. The spatiotemporal pattern of LV blood flow velocities during early filling can be used to estimate intraventricular pressure gradients driving early filling. MRI can provide accurate flow velocity information in the LV, but this method has not been exploited to assess diastolic function in heart failure (HF).

Aim:
To assess differences in intraventricular pressure gradients in heart failure and preserved ejection fraction (HFPEF) and heart failure with reduced ejection fraction (HFREF), compared to subjects without HF.

Methods:
We studied 23 subjects without HF, 13 subjects with HFREF and 14 subjects with HFPEF. Intraventricular flow during diastole was measured using 2D in-plane phase-contrast MRI. We solved the Eulier equations to compute intraventricular pressure gradients during LV early filling (figure) and during ejection.

Results:
Whereas the initial velocity of wave propagation (was not significantly different between the groups, the terminal diastolic propagation velocity during early diastolic filling was significantly slower (P=0.004) in HFREF (5.2 m/s; 95%CI=3.9-6.8) than in patients with HFPEF (9.5; 95%CI=6.6-13.6) or subjects without HF (8.9; 95%CI=7.3-10.7). In contrast, HFPEF was associated with a greater amplitude of the reversal of the base-to-apex intraventricular pressure gradient during early filling (β=-0.34; P=0.04), which was driven by the inertial component.

Conclusions:
HFPEF and HFREF are associated with distinct patterns of intraventricular pressure gradient abnormalities during early diastolic filling. Our findings support fundamental differences in the nature of diastolic dysfunction in these 2 conditions.
Abstract 20385: Pregnancy-Induced Cardiac Hypertrophy is Accompanied by Unique Contractile Properties Not Seen in Other Forms of Physiological Hypertrophy
Authors: Tyrrell Jessica , Kennard Kaitlyn , Makarewich Catherine , Bailey Beth A
Published: July 2021

Background:
Cardiac hypertrophy accompanying pregnancy has generally been categorized as physiologic hypertrophy similar to that seen with exercise, however a reduction in cardiac function in late pregnancy has been suggested. Furthermore, the hemodynamic stress of pregnancy can induce a maladaptive, pathologic hypertrophy in a small number of women. This study seeks to characterize the contractile properties of late-pregnant myocardium.

Methods and Results:
Late Pregnancy (LP) Female Swiss-Webster mice were bred then studied at near term (Embryonic day 17-19) and compared to age-matched, non-pregnant (NP) controls. Individual cardiac myocytes were isolated using collagenase-based perfusion technique. Two-dimensional Surface Area measured in quiescent cells was elevated (p<.01) in LP myocytes (LPM) (3609± 132u
2
) vs NP myocytes (NPM) (2736± 88u
2
), and this increase was due to increases in both length (8.5%) and width (15.6%). Western Blot analysis showed a reduction in Ryanodine Receptor protein in LP, but no differences in L-type Ca Channel, SERCA or Phospholamban levels. Sarcomere length (light diffraction) and Ca
2+
transients (fluo-3) were measured at pacing rates of 1 Hz and at bath [Ca] of 2mM. Duration of twitch contraction was prolonged (p<.05) in LPM as measured by Time to 75% Recovery (.42 ± .02 vs .37 ±.01 sec in NPM) and Time to 90% recovery (.51 ± .02 vs .45 ± .02 sec in NPM). There were no differences in other contractile parameters measured or in the fluo-3 calcium transient properties. 10
-7
M Isoproterenol (ISO) was used to determine the responsiveness to adrenergic stimulation. ISO induced significantly enhanced contractility in both LPM and NPM, and the response was heightened in LPM such that the presence of ISO normalized the differences in the duration of twitch contraction between LPM and NPM.

Conclusions:
These results suggest that hypertrophied LPM have characteristics of both physiologic and pathologic hypertrophy including enhanced responsiveness to ISO and a prolonged relaxation phase. The prolongation of relaxation is not seen in physiologic hypertrophy induced by exercise and may contribute to the diastolic dysfunction reported in some pregnancies. Enhanced response to ISO suggests an increased cardiac reserve in LPM.
Abstract 20411: Depression Screening and Case-Finding Tools in Heart Failure: Timing Matters
Authors: Corvera-Tindel Teresita , Doering Lynn V
Published: July 2021

Depression in HF is associated with noncompliance to treatment recommendations, reduced health status and quality of life, and increased hospital readmission and mortality. Early and accurate screening and case-finding for depression in HF patient is critical. The purpose of this study was to evaluate the performance of common depression screening tools in HF patients in both acute or outpatient setting.

Methods:
At hospital admission, 118 veterans (99% male, 68 ± 10 years) were evaluated for clinical depression; 96 were tested again at 6 months. At both times, 3 screening tools (Beck Depression Inventory [BCI], Patient Health Questionnaire [PHQ]-2, and PHQ-9) were completed. Clinical depression was measured by the Diagnostic Interview Structured Hamilton (DISH) administered by trained nurses. Performance of each tool was evaluated with receiver operating characteristics (ROC) analysis and calculation of sensitivity, specificity, and positive predictive value (PPV).

Results:
In hospital and 6 months later as outpatients, 24 (20.3%) and 14 (14.6%) veterans exhibited clinical depression, respectively. For all 3 tools, area under the curve values were significant (Table). At hospitalization, cut-off scores above those normally suggested provided superior sensitivity, specificity and PPV. For screening with high cut-offs, the BDI and PHQ-9 yield acceptable sensitivity. For case-finding, the BDI exhibited acceptable PPV at a high cut-off. At 6 months, optimal cut-offs all 3 tools approached those normally suggested, with the PHQ-2 yielding a stronger PPV than the BDI or PHQ-9.

Conclusion:
While all 3 tools were useful for depression screening and case-finding in HF, timing relative to hospital admission influences performance. While the BDI works well for screening and case-finding, the PHQ-9 performs better for screening at hospital admission and the PHQ-2 performs better for case-finding 6 months after admission.
Abstract 20426: Study of S-Nitrosylation in Duchenne Muscular Dystrophy
Authors: Chung Heaseung S , Rainer Peter P , Kass David A , Van Eyk Jennifer E
Published: July 2021

Introduction:
Severe cardiac myopathy occurs with Duchenne muscular dystrophy (DMD), a fatal disease characterized by absence of functional dystrophin protein. The mechanisms of the disease in cardiac muscle and whether it mimics some of the pathophysiological mechanisms present in skeletal muscle are not clear. The loss of dystrophin was reported to disrupt neuronal nitric oxide synthase mu, presumably altering redox-signaling. Nitric oxide-induced S-nitrosylation (SNO) on cysteine residues is known as a redox-sensor, which responds to cellular dynamic redox-environment. Here we identified and quantified the SNO-modified sites of cardiac tissue in dystrophy model using a novel proteomics approach.

Methods:
SNO-proteins from cardiac tissues of 10 months-old mdx/utrn+/- (n=3) and C57BL/6 (n=3) mice were detected with our improved TMT (tandem mass tag)-switch technique coupled with liquid chromatography/tandem mass spectrometry. The identified SNO of each site was quantified across DMD and WT samples and the fold change of SNO on each site in DMD compared to WT was displayed as ‘SNO-index (I)’, calculated by SNO
DMD
/SNO
WT
.

Results:
Proteomics analysis identified total 866 SNO-modified peptides on 287 SNO-proteins in the dystrophy cardiac tissue. The magnitudes of SNO-fold change were various across peptides (I=0.1 least to 1702.7 most). 32% of these, 278 peptides were more than two-fold oxidized in DMD than WT. Interestingly, a termed ‘Dilated cardiomyopathy’ protein group by KEGG-pathway analysis has extremely oxidized sites than other groups, which are more than 10-folds S-nitrosylated in DMD. Myosin-6 at Cys949 and Cys1750 (I=11.4, 117.3), Cys432 of myosin-binding protein C (I=135.0) and Cys191 of myosin light chain 3 (I=81.2) displayed a considerable SNO-increase in dystrophy sample and Cys35 of troponin C was also more modified (I=2.9), while other sites such as Cys397 of creatine kinase S-type was less oxidized (I=0.26) in DMD.

Conclusions:
Our novel TMT-switch assay allowed quantification of the very labile SNO-modification as well as site-identification. More than 500 cysteine residues sensed the oxidative stimuli and each had a specific susceptibility to SNO. The SNO-based redox switches were shifted in DMD compared with WT.
Abstract 20492: Mlf1 Regulates Myocyte Proliferation in Postnatal Hearts
Authors: Muralidhar Shalini , Xiao Feng , Thet Suwannee , Sadek Hesham
Published: July 2021

Lower vertebrates, such as newt and zebrafish, retain a robust cardiac regenerative capacity following injury. Although adult mammals lack this cardiac regenerative potential, there is ample interest in understanding how heart regeneration occurs, and to reawaken this process in adult humans. Recently, we showed that mice are capable of regenerating their hearts shortly after birth following injury. This regenerative response is associated with robust proliferation of cardiomyocytes without significant hypertrophy or fibrosis. However, this regenerative capacity is lost by 7 days postnatally, coinciding with cell cycle arrest. In an effort to determine the mechanism of cardiomyocytes cell cycle arrest after the first week of life, we performed a gene array after cardiac injury at multiple post-natal time points. This enabled us to identify a number of transcription factors that are differentially expressed during this postnatal window. We recently reported that one of these transcription factors Meis1 regulates postnatal cell cycle arrest of cardiomyocytes. Furthermore, Myeloid leukemia factor 1 (Mlf1), a bhlh transcription factor that has not been previously studied in the heart has similar dysregulated pattern following injury. Our preliminary data with in-vitro knockdown of Mlf1 in cardiomyocyte resulted in 2-fold increase in cardiomyocyte proliferation. Furthermore, immunohistochemistry results indicated that the endogenous expression and nuclear localization of Mlf1 in the post-natal cardiomyocytes coincides with cell cycle arrest. To explore this pattern, we generated a cardiomyocyte-specific Mlf1 knockout mouse, and showed that loss of Mlf1 results in robust cardiomyocyte proliferation in postnatal hearts (P14). Additionally, we confirmed previous reports that Mlf1 regulates p53 and induces cell cycle arrest by induction of CDK inhibitors like p21 and p57 in these Mlf1 KO mice. This suggests a role of Mlf1 in promoting reactivation of injured myocardium through induction of cardiomyocyte proliferation. These findings will further provide evidences of molecular mechanisms involved in the dormant regenerative capacity in adult mammals that can be a potential target of therapeutic approaches.
Abstract 20500: Trx1 Promotes Trans-Nitrosylation of Cellular Proteins to Stimulate Autophagy and Cell Survival
Authors: Nagarajan Narayani , Sciarretta Sebastiano , Sadoshima Junichi
Published: July 2021

Thioredoxin-1 (Trx1) is cardioprotective during oxidative stress, mainly through its antioxidant activity. Trx1 is also S-nitrosylated and, in turn, trans-nitrosylates other proteins. However, the role of Trx1-dependent S-nitrosylation in cardiomyocytes (CMs) is unknown. Here, we investigated the role of Trx1-mediated protein S-nitrosylation in the regulation of CM survival during stress in vitro. Using biotin-switch assays, we found that wild-type Trx1 (Trx1WT) is S-nitrosylated at baseline, but the extent of S-nitrosylation was attenuated in Trx1C73S, suggesting that Trx1 is S-nitrosylated at Cys73. Trx1WT and Trx1C73S do not differ in their redox activity, as determined by Amplex Red assays. Cellular protein S-nitrosylation levels were increased after 4 hours of glucose deprivation (GD), an energy stress condition (1.64±0.27 fold, p<0.05), as determined by biotin switch assays. Overexpression of Trx1WT increased (3.94-fold), whereas knockdown of Trx1 (0.66±0.01 fold, p<0.01) or overexpression of Trx1C73S (0.77±0.02 fold, p<0.01) decreased, total protein S-nitrosylation in response to GD. These results suggest that Trx1C73 regulates protein S-nitrosylation in CMs during GD. Overexpression of Trx1 increased CM survival after 24 hours of GD (1.42±0.08 fold vs LacZ, p<0.05), as evaluated with propidium iodide assays. Conversely, shTrx1 (2.13±0.05 fold vs control, p<0.01) or Trx1C73S (1.73±0.034 fold vs LacZ, p<0.01) increased cell death during GD. Either knockdown of Trx1 (LC3-II/Tubulin: 0.55 fold vs control) or overexpression of Trx1C73S (vs LacZ: LC3-II/Tubulin, 0.60 fold; autophagosomes, 0.83±0.16-fold, p<0.005; autolysosomes, 0.62±0.13-fold, p<0.005) significantly decreased autophagy during GD. Mechanistically, Trx1 co-immunoprecipitates with Atg7, an E1-like protein which plays a critical role in mediating autophagy. Using mass spectroscopy analyses, we found that SNO-Trx1 can trans-nitrosylate Atg7 in vitro. These results suggest that Trx1 trans-nitrosylates Atg7 during GD. Taken all together, our results indicate that Trx1 promotes trans-nitrosylation of cellular proteins, including Atg7, and autophagy, thereby promoting cell survival during energy stress in CMs.
Abstract 20504: Dysfunctional cAMP-Dependent Protein Kinase (PKA) Signaling Causes Impaired Autonomic Control in Diabetic Heart Failure
Authors: Bockus Lee , Humphries Kenneth
Published: July 2021

Autonomic control of cardiac function primarily occurs through the regulation of cAMP-dependent protein kinase (PKA) via the adrenergic and muscarinic pathways. The diabetic heart has a suppressed β-adrenergic response that is classically attributed to β-adrenergic receptor internalization, but little is known about how the PKA signaling pathway is affected. We assessed the hypothesis that β-adrenergic impairment in diabetes occurs through PKA signaling dysfunction. Four-month streptozotocin (STZ)-induced diabetic mice were used in this study as a model of diabetic cardiomyopathy. Although the diabetic mice have substantial cardiac impairment, as measured by pressure catheter, cAMP levels are not reduced, suggesting the pathway upstream of PKA is intact. We next developed a novel system using acute 8-min treatments with a cAMP analog, 8Br-cAMP, to activate PKA in a receptor-independent manner and increase ventricular inotropy. Diabetic mice have an impaired response to 8Br-cAMP treatment as shown by minimal change in PKA substrate phosphorylation (Fig. 1) and PKA activity by enzyme assay (% increase, C: 65±3.5, STZ: 30±5, n=5). Interestingly, cytosolic phosphorylation of PFK-2 is absent (% increase, C: 142±32, STZ: -15.7±13, n=5), yet nuclear phosphorylation of CREB is maintained suggesting a difference in localization of PKA. Although total PKA content is not different in the diabetic hearts, there is reduced cytosolic content of PKA (-35±1%, n=5) and an increase in nuclear translocation of PKA with treatment. The improper localization of PKA in the diabetic mice explains the differing phosphorylation. A major contributor is the reduction of nuclear PKA inhibitors/exporters, PKIα (-33±6.2%, n=5) and PKIγ (-20±7.2%, n=5), which normally regulate the nuclear content of PKA. In conclusion, PKA signaling is greatly impaired in diabetes and is attributable to altered enzyme localization, which is at least in part a result of PKI loss.
Abstract 20517: MicroRNA-155: A New Player in Sepsis-Induced Cardiac Dysfunction
Authors: Vasques-Nóvoa Francisco , Quina-Rodrigues Catarina , Cerqueira Rui , Baganha Fabiana , Marques Mariana I , Leite-Moreira Adelino F , Roncon-Albuquerque Roberto
Published: July 2021

Introduction:
Cardiac dysfunction is an important outcome predictor in patients with septic shock and lacks effective and targeted therapies. MicroRNA-155 (miR-155) is a multifunctional microRNA with important target genes in inflammation, immunity and cardiovascular system.

Hypothesis:
The present study assessed the role of miR-155 in experimental and human sepsis-induced cardiac dysfunction.

Methods:
Experimental sepsis was induced using endotoxin injection (LPS) or cecal ligation and puncture (CLP) models. Genetic loss (miR-155 KO) and pharmacological inhibition (LNA-anti-miR; AM) of miR-155 were evaluated. Cardiac function was assessed through echocardiography; mortality analysis was also performed. Quantification of myocardial miR-155, pro-inflammatory cytokine mRNA profile, miR-155 targets, apoptosis, cellular adhesion proteins and activation of pro-inflammatory intracellular signaling pathways were assessed. In another experiment, myocardial miR-155 expression, cellular localization and associations between its levels and other clinical variables were evaluated using post-mortem samples from septic shock (SS) patients.

Results:
Myocardial miR-155 levels were increased in experimental and human septic myocardium. This was associated with a decreased ejection fraction (EF) and cardiac output (CO) and increased diastolic LV diameter (LVDd) in septic WT animals. Knockout and anti-miR-155 treated animals and presented with preserved EF, CO and LVDd, compared with WT; this was accompanied by ~50% mortality reduction. Experimental sepsis induced downregulation of SOCS1 and CD47, myocardial cytokine upregulation, increased apoptosis and adhesion protein expression as well as pro-inflammatory kinase and transcription factor activation, all of which were attenuated in KO and AM. In human myocardium, miR-155 expression was positively associated with 24h antemortem period plasma troponin I levels.

Conclusions:
miR-155 is upregulated in experimental and human septic myocardium. Loss or inhibition of miR-155 attenuated sepsis-induced cardiac dysfunction, blunted proinflammatory activation and reduced mortality. This suggests miR-155 as a potential target in human sepsis-associated cardiac dysfunction.
Abstract 20538: Nrf2 Signaling Ameliorates Ventilator-Induced Lung Inflammation
Authors: Wang Ting , Jiang Tao , Quijada Hector , Mascarenhas Joseph B , Ramamoorthi Elangovan Venkateswaran , Hecker Louise , Lussier Yves A , Yuan Jason X , Zhang Donna D , Garcia Joe G
Published: July 2021

Ventilator-induced lung injury (VILI) is an acute lung injury that develops during mechanical ventilation with high tidal volume in patients in the intensive care unit (ICU). VILI is a common entity with an unacceptable mortality rate (~20%). As no current therapies exist for VILI, novel therapeutic targets for VILI and mechanical stress-induced tissue injury are needed. In this study, we defined Nrf2 signaling in VILI and mechanical stress-induced endothelial cell pathobiology. Nrf2 is a transcription factor that alters ROS balance and is a novel therapeutic target for VILI. First, we defined Nrf2 as a sensory marker for mechanical stress-induced endothelial cell injury. Antioxidant response element (ARE) luciferase plasmids were transfected to both endothelial cells and murine lung tissues. EC exposed to 18% cyclic stretch (18% CS) or mice exposed to excessive tidal volume ventilation (40 ml/kg) resulted in ARE activation, site of Nrf2 binding. We next confirmed Nrf2 signaling is essential for gene expression dysregulation by 18% CS via Nrf2 knockdown that significantly ameliorates 18% CS-induced gene expression pattern, including signaling pathways regulating endothelial barrier function including MYLK. Finally, we validated that Nrf2 is a novel and effective therapeutic target for VILI in pre-clinical models of VILI. Nrf2 activator sulforaphane (SF, 11.5 mg/kg) significantly attenuated VILI (40 ml/kg, 4 hrs)-induced lung inflammation, including BAL protein leakage and white blood cell infiltration. These novel findings characterized Nrf2 as a sensor for mechanical stress, a central mediator of mechanical stress induced gene expression dysregulation, and a novel therapeutic target for VILI.
Abstract 20552: Comparison of Outcome in Patients With ST-Elevation Myocardial Infarction Treated with Drug-Eluting Stents versus Bare Metal Stents in Eastern Denmark and Southern Sweden
Authors: Waziri Homa , Jorgensen Erik , Kelbaek Henning , Stagmo Martin , Pedersen Frants , James Stefan , Lagerqvist Bo , Kober Lars , wachtell Kristian
Published: July 2021

The prognosis of patients with ST-elevation myocardial infarction (STEMI) has improved significantly in the era of mechanical revascularization. Regional differences exist in the choice of stents. The aim of this study was to assess whether differences in preference of stents effect outcome in Danish and Swedish STEMI patients treated with either drug-eluting stents (DES) or bare metal stents (BMS) during percutaneous coronary intervention (PCI) in Eastern Denmark and Southern Sweden, respectively.

Methods:
We included 14,260 consecutive STEMI patients from 2003-2012 (59,708 patient-years of follow-up) treated in Eastern Denmark and Southern Sweden with either DES or BMS. Data were obtained from the Eastern Danish Heart Registry and the Swedish Coronary Angiography and Angioplasty Registry.

Results:
We identified 7828 (54.9%) Danish and 6,432 (45.1%) Swedish patients. Among Danish patients 76% (n=5966) received DES whereas 82% (n= 5254) of the Swedish patients received BMS. Overall 7116 (49.9%) patients were treated with DES and 7144 (50.1%) with BMS. Patients who received BMS were older (65.9 vs. 63.0) with a higher prevalence of hypertension (38.9 % vs. 36.3%) and history of myocardial infarction (13.0% vs. 9.2%) but with a lower prevalence of smoking (42.1% vs. 50.7%) and hyperlipidemia (20.7% vs. 24.3%, all p<0.01). Patients with BMS had a higher risk adjusted 30-day mortality (hazard ratio [HR] =1.3, CI 1.02-1.68, p<0.001) compared with DES. There was no statistically significant difference in mortality after 30 days and onwards (HR=0.96, CI 0.83-1.1, p=0.59)

Conclusions:
The use of DES is associated with a significantly lower 30-day mortality compared with BMS. After 30-days there is no difference in mortality between DES and BMS.
Abstract 20574: Selective Activation of the PI3K/Akt Pathway With the Insulin Mimetic Demethylasterriquinone B1 Reverses Neuroinflammatory-Mediated Blood-Brain Barrier Dysfunction in Mice
Authors: Beard Richard S , Haines Ricci J , Overstreet Jonathan W , Meegan Jamie E , Wu Mack H , Yuan Sarah Y
Published: July 2021

Blood-brain barrier (BBB) dysfunction is a hallmark of neuroinflammation brought on by pathologies such as stroke and amyloid angiopathy. Inflammatory cytokines that act directly on cerebral endothelium can impair tight junction (TJ) stability. We previously identified a mechanism for IL-1β-mediated dysfunction involving inactivation of the PI3K/Akt pathway, activation of the transcription factor FoxO1, and FoxO1-dependent transcriptional repression of the TJ gene claudin-5 (Cldn5). Here we used an insulin mimetic, Demethylasterriquinone B1 (DMAQ-B1), to test the hypotheses that targeted activation of the PI3K/Akt pathway: 1) enhances cerebral endothelial barrier function, 2) reverses IL-1β-mediated dysfunction and 3) attenuates neuroinflammation-induced BBB dysfunction. In Vitro: Primary cerebral microvascular endothelial cells (CMVECs) were grown in collagen-coated dishes, transwell inserts (0.4 μm pores), or ECIS Arrays (Applied Biophysics). Culture media was conditioned with vehicle control, IL-1β (100 ng/mL), and/or DMAQ-B1 (2.5-10 μM). DMAQ-B1 dose-dependently activated Akt (increased pT308), inactivated FoxO1 (decreased nuclear localization), increased Cldn5 expression (WB, ICC), increased transendothelial electrical resistance (TER), and decreased CMVEC monolayer permeability (Ps). Akt silencing (siRNA), PI3K inhibition (LY294002), or IL-1β treatment downregulated Cldn5 and induced CMVEC barrier dysfunction. DMAQ-B1 (5 μM) reversed IL-1β-mediated Akt inactivation, FoxO1 activation, Cldn5 downregulation and CMVEC barrier dysfunction. In Vivo: We used a murine model of neuroinflammation, experimental autoimmune encephalomyelitis (EAE). Cerebral microvascular enriched fractions from EAE-induced mice had less pT308 Akt, increased FoxO1 nuclear accumulation, and decreased Cldn5 expression compared to control. Decreased Cldn5 expression and increased BBB hyperpermeability (sodium fluorescein extravasation) observed in EAE-induced mice was attenuated by 24 hour DMAQ-B1 (5 mg/kg; oral gavage) treatment. These results indicate that promoting PI3K/Akt pathway activation with DMAQ-B1 during neuroinflammatory pathologies may provide a novel therapeutic approach to attenuate BBB dysfunction.
Abstract 20577: Combination of Global Longitudinal Strain and Sympathetic Nervous Dysfunction Predicts Cardiac Events in Patients With Non-Ischemic Dilated Cardiomyopathy
Authors: Chimura Misato , Onishi Tetsuari , Kawai Hiroya , Yamada Shinishiro , Yasaka Yoshinori
Published: July 2021

Introduction:
It has been reported that sympathetic nervous dysfunction by 123I-metaiodobenzylguanidine (MIBG) is associated with worse outcome in dilated cardiomyopathy (DCM) patients. However, the association between sympathetic nervous function and myocardial strain is not established.

Hypothesis:
Global longitudinal strain (GLS) by two-dimensional speckle-tracking echocardiography (2DSTE) is correlated with sympathetic nervous activity, and stratifies DCM patients at risk for cardiac events with a combination of sympathetic nervous activity.

Methods:
We studied 71 patients who had admitted to a cardiology department with heart failure at the initial visit (age 61±13 years, 45 males, LV ejection fraction (EF) 30±8 %). All patients underwent MIBG imaging for the delayed heart to mediastinum ratio (H/M), and echocardiography with conventional assessment including left atrial volume (LAV), LV end-diastolic and end-systolic volume (LVEDV, LVESV), LVEF, mitral regurgitation grade (MR), early transmitral flow to atrial contraction (E/A) and with 2DSTE analysis for GLS expressed with an absolute value. Cardiac events were assessed according to death and hospitalization with heart failure.

Results:
There were 21 cardiac events in the follow-up period for 4.9±2.3 years. Univariate regression analysis showed LAV, LVEDV, LVESV, LVEF, MR, E/A and GLS had a significant correlation with delayed H/M (all p < 0.05). Multivariate regression analysis revealed that GLS was an independent predictor of delayed H/M. Dividing all patients into 4 groups by the median of GLS in patients with delayed H/M >1.6 or≤1.6, the combination of the worse delayed H/M and the worse GLS was significantly associated with cardiac events (p=0.03).

Conclusions:
Left ventricular GLS is significantly correlated with delayed H/M and can be useful to stratify the risk in DCM patients with a combination of delayed H/M.
Abstract 20587: Myocyte-Specific Over-Expression of Hdac4 Promotes Myocardial Ischemia and Reperfusion Injury
Authors: Zhang Ling , Du Jian Feng , Zhao Yu , Zhao Ting C
Published: July 2021

Background:
Histone deacetylases (HDACs) have been recently demonstrated to play a critical role in modulating myocardial protection and cardiomyocyte survival. However, the specific HDAC in mediating myocardial ischemia/reperfusion injury is currently unknown.

Objective:
The goal of this study is sought to define whether cardiac specific over-expression of HDAC4 would exacerbate myocardial ischemia and reperfusion injury.

Methods:
We created myocyte-specific HDAC4 transgenic mice, in which cDNA encoding HDAC4 was cloned into an expression vector encoding alpha-myosine heavy chain (the α-MHC promoter). Langendorff isovolumetrically perfused hearts from wild type (WT) control (n=5) and α-MHC-HDAC4 mice (n=5) were subjected to 30 minutes of ischemia followed by 30 minutes of reperfusion. Infarct size was measured by triphenyl tetrazolium chloride staining. HDAC4 protein and activity in myocardium were determined.

Results:
The HDAC4 protein levels in the hearts of α-MHC-HDAC4 mice were significantly higher than those of control wild type. HDAC activity was elevated in MHC-HDAC4 mice as compared with wild type mice. In adult mice, there was no significant difference in the heart weight-body weight ratio between α-MHC-HDAC and wild-type mice. As compared to wild type mice, myocyte-specific over-expression of HDAC4 resulted in an elevation of left ventricular end-diastolic pressure (LVEDP) and reduction in the recovery of rate and pressure products (RPP) at the end of reperfusion. Furthermore, over-expression of HDAC4 increased myocardial infarct size as compared to wild type mice.

Conclusions:
These findings indicate that specific over-expression of HDAC4 exacerbates myocardial ischemia and reperfusion injury.
Abstract 20609: Abnormalities of Mitochondrial Number and Function in Pediatric Idiopathic Dilated Cardiomyopathy
Authors: Chatfield Kathryn C , Friederich Marisa W , Miyamoto Shelley D , Sucharov Carmen C , Van Hove Johan L , Stauffer Brian L
Published: July 2021

Introduction:
Impaired mitochondrial energy production and substrate utilization have been implicated in the development of heart failure (HF) in adults. Little literature exists describing mitochondrial energetics in pediatric HF. We have previously shown that content of Cardiolipin (CL), a major mitochondrial membrane phospholipid, is depleted in both adult and pediatric idiopathic dilated cardiomyopathy (IDC), with preserved expression of mitochondrial-encodes genes. Similar CL changes occur in a rat model of HF with associated mitochondrial dysfunction that precedes myocardial dysfunction, which can be reversed by dietary interventions.

Hypothesis:
We hypothesize that mitochondrial dysfunction occurs in pediatric IDC.

Methods:
As a part of an on-going study a cross-sectional analysis of mitochondrial content and function was performed in left ventricle tissue from the University of Colorado Pediatric Heart Tissue Bank. Current contents: age 13-18: 11 IDC (64% male) and 13 NF (62% male). All NF are donor hearts with normal LVEF; all IDC specimens had LVEF <30%.

Results:
We show lower mitochondrial copy number in pediatric IDC compared with NF controls (IDC: 44 vs NF: 24, P<0.05), with paradoxical up-regulation of transcriptional co-activators, PGC1α and NRF1 (P<0.01). This is in contrast to what has been shown in adult HF where PGC1α and NRF1 expression are unchanged. Electron transport chain (ETC) complex enzymatic activities were quantified in a sub-group of pediatric IDC samples, expressed as Z-scores relative to normative values in 18 NFs. Significantly decreased activities of complexes I, IV, and citrate synthase were found (Z-scores -2.2, -3.3 and -1.7 respectively), with a significant increase in complex III activity (Z-score 0.7, all P<0.05).

Conclusions:
These results suggest impaired mitochondrial biogenesis occurs in pediatric HF by a unique mechanism from that seen in adults. Additionally, we show a very specific pattern of ETC dysfunction in pediatric IDC. Future studies will identify the how decreased mitochondrial copy number occurs in the context of PGC1α and NRF1 up-regulation and determine whether abnormalities in CL contribute to abnormalities in ETC activities.