bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1349: Overexpression And Dominant-negative Suppression Of Inwardly Rectifying Potassium Channel Protein (Kir2.1) Alters Electrophysiology And Spiral Wave Dynamics Of An
In Vitro
Model Of Cardiac Myocytes
Authors: Sekar Rajesh B , Kizana Eddy , Cho Hee C , Smith Rachel R , Eaton Brett P , Marbán Eduardo , Tung Leslie
Published: July 2021

Introduction
: An important role for the inwardly rectifying potassium current (I
K1
) has been postulated in controlling the stability and frequency of rotors responsible for ventricular tachycardia and fibrillation. We investigated the effects of Kir2.1 overexpression and Kir2.1AAA dominant-negative mutant suppression on the electrophysiology and inducibility, stability and frequency of spiral waves in an
in vitro
cardiac tissue model.

Methods/Results
: Neonatal rat ventricular myocytes (NRVMs) were transduced by lentiviral vectors encoding Kir2.1 or Kir2.1AAA. Immunostaining revealed Kir2.1 or mutant Kir2.1 protein overexpression and whole cell-clamp confirmed the predicted effects on I
K1
, resting potential, and action potential duration (APD
80
). Optical mapping was performed on confluent NRVM monolayers containing a 5 mm diameter central island of gene-modified NRVMs created by a stenciling technique. APs propagated with increased CV (25.1±2.7 cm/sec, n=7) and shortened APD
80
(73±11 msec, n=7) in islands of Kir2.1 overexpression, or decreased CV (13.1±1.1 cm/sec, n=7) and prolonged APD
80
(263±14 msec, n=7) in islands of Kir2.1AAA suppression, compared with normal CV and APD
80
of 19.2±0.4 cm/sec and 169±14 msec (n=7) in non-transduced islands. Reentry was initiated by rapid pacing. With Kir2.1 overexpression, reentrant waves anchored to the island and remained stable (89±15 minutes, n=3) with a frequency of 8±2 Hz. Superfusion with 0.5 mM BaCl
2
to block I
K1
slowed reentry to 1 Hz and terminated it shortly after initiation. NRVM monolayers with islands of Kir2.1AAA suppression (n=3) displayed rapid spontaneous activity. Rapid pacing of these monolayers initiated an unstable figure-of-eight reentry (n=3) that degraded into single and multi-armed spiral waves, anchored to varying parts of the island with a maximum frequency of 2±1 Hz. Importantly, no reentry could be initiated in monolayers with non-transduced islands (n=3).

Conclusion
: Functional reentrant waves induced by rapid pacing are anchored to islands of localized Kir2.1 overexpression whereas they drop in frequency and meander in islands of dominant-negative suppression of Kir2.1, confirming the importance of I
K1
for the stability of these waves in cardiac tissue.
Abstract 241: Direct Injection of Bone Marrow Mononuclear Cells Reversed Experimental Diabetic Neuropathy by Augmenting Neovascularization and Providing Angio-neurotrophic Cytokines
Authors: Kim Hyongbum , Choi Yong Jin , Park Jong-seon , Ii Masaaki , Silver Marcy , Pfannl Rolf , Ropper Allan , Yoon Young-sup
Published: July 2021

Background: Bone marrow (BM)-derived mononuclear cells (MNCs) have been shown to effectively treat ischemic cardiovascular diseases. Recent evidence suggested that diabetic neuropathy (DN) is causally related to impaired angio-vasculogenesis in vasa nervorum and deficiency of angiogenic and neurotrophic factors. Accordingly, we sought to investigate whether DN can be ameliorated by local injection of BM-derived MNCs.

Methods and Results: A severe peripheral neuropathy, characterized by significant slowing of motor nerve conduction velocities (MCV) developed 12 wks after the induction of diabetes with streptozotocin in Fisher rats (vs normal rats; 46.6±2.6 vs 32.0±2.5 m/s, P < 0.05). These rats were randomly assigned to MNC or saline injection groups (n = 9, each group) and received either 5x106 MNCs or saline intramuscularly around the sciatic nerves. In the MNC group, MCV were significantly improved within 4 wks after treatment (MNC vs Saline, 41.9±3.2 vs 32.7±2.8 m/s, P < 0.01). Microvascular circulation of sciatic nerve, measured by laser Doppler perfusion imaging was markedly increased only in the MNC group. Capillary density at 4 wks was significantly higher in the MNC group than in the saline group (68±5.9 vs 37±4.4 /cross section, P < 0.01). Robust engraftment of MNCs were observed in sciatic nerves, which sustained over 4 wks. A fraction of engrafted MNCs expressed endothelial markers suggestive of transdifferentiation into endothelial cells in the vasa nervorum. Intriguingly, a large number of the engrafted MNCs are following the course of vasa nervorum in close proximity. Real-time RT-PCR on sciatic nerves revealed that the expression of angio-neurotrophic factors were significantly increased in the MNC group compared to the saline group: VEGF (2.1 fold), FGF-2 (2.4), eNOS (18.1), Brain-derived neurotrophic factor (35.1), IGF-1 (25.5) (all P < 0.05). The protein levels were well correlated with mRNA expression levels.

Conclusion: Local transplantation of BM-derived MNCs could improve experimental DN by augmenting neovascularization and increasing angiogenic and neurotrophic factors in peripheral nerves. These findings suggest that BM-MNC transplantation may represent a novel therapeutic option for treating DN.
Abstract 1388:
Hdlq14
Gene, A New Gene Regulating HDL Levels
Authors: Su Zhiguang , Cox Allison , Shen Yuan , Stylianou Ioannis , Paigen Beverly
Published: July 2021

Background

. The discovery of new genes responsible for regulation of high-density lipoprotein cholesterol (HDL) has great clinical relevance since increases in HDL can reduce cardiovascular disease risk. Quantitative trait locus (QTL) analysis is a means of finding novel genes that regulate complex traits, such as atherosclerosis and HDL.
Hdlq14
and
Hdlq15
, two closely linked QTLs for HDL on mouse Chr 1, have been detected by using an intercross between strains C57BL/6 (B6) and 129S1/SvImJ (129).
Apoa2
is the gene for
Hdlq15
locus, but the gene for
Hdlq14
is unknown.

Methods:

To confirm the
Hdlq14
and identify the candidate gene, we performed QTL analysis in a F2 population generated from strains NZB and NZW, which are same at
Apoa2
to avoid its strong effect on the nearby QTL.
Hdlq14
was further narrowed by several strategies including combining crosses, comparative genomics, and haplotype analysis. The reduced lists of candidate genes were evaluated by their expression or sequence differences between the strains that caused the
Hdlq14
. Finally, other HDL crosses, including NZOxNON, B6xC3H, and Pera x D2, were examined to point out the QTL gene. The relationship between the polymorphism at the
Hdlq14
gene and HDL was analyzed in 43 genetically diverse mouse strains.

Results:

Hdlq14
was proved in cross NZBxNZW and the critical interval was reduced from 45 Mb harboring 271 genes to 1.65 Mb containing 15 genes by using bioinformatics tools. Six of these 15 genes have polymorphisms that changed an amino acid; and two genes were found have a significant expression difference between strains B6 and 129. The
Hdlq14
gene was further pointed out using HDL QTL identified in crosses including NZOxNON, B6xC3H, and PeraxDBA. In 43 genetically diverse mouse strains, we found that strains with one allele of the
Hdlq14
had significantly higher plasma HDL levels than those with the other variant.

Conclusions:

The
Hdlq14
was identified as a new HDL-regulating gene.
Abstract 248: Stabilization of cIAP2 during Postconditioning protects Endothelial Cells from Reperfusion Injury
Authors: Gadiraju Krishnaveni , Haertel Frauke V , Piper Hans M , Noll Thomas
Published: July 2021

Hypoxia-reperfusion causes a perturbance in the complex equilibrium of pro and anti apoptotic mechanisms which ultimately leads to apoptosis in the reperfused myocardium. Postconditioning (intermittent hypoxia at the onset of reperfusion) is a proven strategy to reduce reperfusion injury, however, the mechanisms are largely unknown in endothelial cells. Here we analyze the effect of postconditioning in endothelial cells and
hypothesize
that the ‘inhibitors of apoptosis proteins’ (IAPs), known as antiapoptotic mediators, are key elements of this protective mechanism.

Methods and Results:
Exposure of human umbilical vein endothelial cells to severe hypoxia (Po
2
< 2 mmHg) for 2 hrs causes a 2.1±0.5-fold increase in caspase 3 activation (western blot analysis; P<0.05, n=3, for all further parameters) and a 2.3±04-fold increase in apoptosis (annexin V staining) after 24 hrs of reoxygenation. cIAP2 but not cIAP1 is rapidly increased during hypoxia in a biphasic manner. Transcription inhibitor, Actinomycin D (20μg/ml) reveals that the 2.5-fold increase within 5 min of hypoxia (first phase) was independent of transcription, but the 3.1-fold increase after 60 min (second phase) was induced by gene transcription. cIAP2 levels dropped down to basal value with the onset of reperfusion. Importantly, cIAP2 levels could be maintained by postconditioning (3 short periods of intermittent hypoxia, 5 minutes each separated by a 5 minute reoxygenation) which abolished hypoxia-reoxygenation-induced apoptosis. Down regulation of IAP2 by siRNA strategy enhanced hypoxia-reoxygenation-induced apoptosis and diminished the protective effect of postconditioning.

Conclusions:
The present study shows for the first time that postconditioning can protect endothelial cells against hypoxia-reoxygenation induced apoptosis. This protective effect is conferred by the cIAP2, which is stabilized during hypoxia and could be maintained at an elevated level by postconditioning.
Abstract 1420: Mitochondrial Arginase II Constrains Endothelial NOS Activity
Authors: LIM Hyun Kyo , Lim Hyun Kyoung , Ryoo Sungwoo , Benjo Alex , Shuleri Karl , Soucy Kevin , Nyhan Daniel , Shoukas Artin , Berkowitz Dan E
Published: July 2021

Background:
Arginase II is known as a major isoenzyme in the vascular endothelial cells of humans and other species and modulates endothelial nitric oxide synthase (eNOS) activity by regulating intracellular L-arginine bioavailability. We tested under hypothesis that subcellular localization of arginase II is confined to the mitochondria and mitochondrial arginase II deficiency reciprocally regulates the vascular endothelial NO production, contributes to improve endothelial dysfunction and decrease vascular stiffness.

Methods and Results:
Western blot, immunocytochem with Mitotracker and immunoEM confirmed that arginase II is confined predominantly but not exclusively to the mitochondria. Arginase activity was significantly reduced, whereas NO production was significantly increased in aorta and isolated endothelial cells from arginase II knock out (ArgII−/−) compared to WT mice. Vasorelaxation to acetylcholine (ACh) was markedly enhanced and vasoconstriction to phenylephrine (PE) was impaired in ArgII−/− rings. Furthermore inhibition of eNOS by N
G
-nitro-L-arginine methyl ester (L-NAME) impaired ACh response and restored PE response. The baseline pulse wave velocity was significantly decreased in ArgII
−/−
mice (3.30 ± 0.21 vs. 3.64 ± 0.12 m/s, ArgII
−/−
vs. WT, *p<0.01), while 14 days of L-NAME treatment resulted in significant increase the PWV in both WT (4.23 ± 0.11 m/s, **p<0.001) and ArgII
−/−
mice (4.36 ± 0.20 m/s, **p<0.001).

Conclusions:
These data suggest that arginase II is predominantly confined to the mitochondria and this mitochondrial arginase II regulate the NO production, vascular endothelial function, and vascular stiffness by modulating eNOS activity.
Abstract 1432: Nitric Oxide Bioavailability is Lower in Endothelium of Healthy Mexican American Donors as Compared to Non-Hispanic White Donors: Effect of Nebivolol
Authors: Mason R. P , Kubant Ruslan , Malinski Christopher , Jacoby Adam , Jacob Robert F , Day Charles A , Malinski Tadeusz
Published: July 2021

Background:
Epidemiologic studies indicate that Mexican Americans (MA) have a higher prevalence of CV risk factors and disease as compared with non-Hispanic whites (NHW). This increase in CV risk may be due, in part, to differences in endothelial function. In this study, we measured endothelial function in cells from normotensive, age-matched MA and NHW donors, as well as the effects of treatment with nebivolol, a new β
1
-selective blocker with vasodilating properties.

Methods:
Endothelial nitric oxide (NO) and peroxynitrite (ONOO
−
) release in human umbilical vein endothelial cells (HUVECs) from age-matched MA and NHW donors were measured simultaneously using a nanosensor array. The effects of nebivolol on NO and ONOO
−
release were evaluated following pretreatment (24 h) with a calcium ionophore (CaI) as a receptor-independent stimulus. Endothelial NO synthase (eNOS) levels were measured by Western blot analysis, and drug-membrane interactions were determined by small angle x-ray diffraction approaches.

Results:
NO bioavailability in endothelial cells of MA donors was 30% lower than that of cells from NHW donors (383 ± 10 nM versus 543 ± 8 nM, n=6) following stimulation with CaI (1.0 μM). Pretreatment with nebivolol (1.0 μM) eliminated these interracial differences and enhanced NO release disproportionately in MA cells (57%) versus NHW cells (20%). Nebivolol also reduced ONOO
−
levels in MA endothelium by 75% (746 ± 12 nM to 195 ± 10 nM) and by 50% in NHW cells (416 ± 7 nM to 191 ± 13 nM). The ratio of NO to ONOO
−
, an indicator of eNOS coupling, increased more than 5-fold in MA cells following nebivolol treatment. In addition, eNOS levels were 40% lower in MA endothelium compared to NHW, but increased 2-fold with nebivolol treatment. These effects were not observed with atenolol, a hydrophilic β
1
-selective antagonist.

Conclusion:
We observed differences between Mexican Americans and non-Hispanic whites in endothelial NO bioavailability and nitroxidative stress–factors that may contribute to increased CV risk. Treatment with nebivolol, but not atenolol, enhanced both the expression and coupling efficiency of eNOS in Mexican American endothelium.
Abstract 1440: Endothelial And Cardiomyocyte Toxicity Of Endogenously Produced Nucleoside: 4-pyridone-3-carboxamide-1-β-d-riboside
Authors: Slominska Ewa M , Orlewska Czeslawa , Terracciano Cesare M , Yuen Ada H , Siedlecka Urszula , Yacoub Magdi H , Smolenski Ryszard T
Published: July 2021

Our recent studies identified hitherto unknown, naturally occurring nucleotide: 4-pyridone-3-carboxamide-1-β-D-ribonucleoside triphosphate (4PYTP). This nucleotide was found to accumulate in the erythrocytes of patients with chronic renal failure, a condition that precipitates heart failure and atherosclerosis. We found also increase in plasma concentration of nucleoside precursor of 4PYTP: 4-pyridone-3-carboxamide-1-β-D-ribonucleoside (4PYR) in patients with renal failure. This study was aimed to evaluate metabolism and potential toxic effect of this nucleoside in cardiomyocytes and endothelial cells. We used human erythrocytes isolated from peripheral blood, human endothelial cell line HMEC-1 cell line and cardiomyocytes isolated from rat hearts. Cells were incubated with chemically synthesized 4PYR. Metabolic assessments were performed with HPLC or liquid chromatography/mass spectrometry. We demonstrated formation of 4PYTP in human erythrocytes during incubation with 4PYR. We noted however, preferential accumulation of monophosphate of 4PYR (4PYMP) over 4PYTP. Concentration of 4PYMP increased in the erythrocytes from below 5 μM to 76.9±7.1, 254.7±13.9 and 674.3±34.3 μM after 6h incubation with 0.1, 0.3 and 1 mM 4PYR. 4PYMP progressively accumulated in the cultured endothelial cells during incubation with 4PYR up to 72 h. Cardiomyocytes were also shown to accumulate 4PYMP. In all cell types formation of 4PYR nucleotides was accompanied by decrease in cellular ATP concentration. Furthermore, treatment with 4PYR and formation of its nucleotides in endothelial cells reduced NO synthase pathway while in cardiac myocytes resulted in prolongation of action potential. We conclude that endogenously formed 4PYR is effectively metabolized to nucleotide derivatives in the erythrocytes, cardiomyocytes and endothelium. Depletion of ATP in these cells accompanying 4PYR metabolism and deleterious effects on cell function suggests that accumulation of 4PYR and its enhanced metabolism to nucleotides in endothelium and cardiomyocyted may contribute to cardiovascular pathology observed in chronic renal failure.
Abstract 1455: Athero-protective Role of IL10 Involves Regulation of Lipid Metabolism in Macrophages
Authors: Han Xinbing , Kitamoto Shiro , Lian Qingyu , Boisvert William A
Published: July 2021

Introduction
Previous studies utilizing interleukin (IL)10-overexpressing mice and IL10-deficient mice have demonstrated an anti-atherogenic role of IL10. Internalization of modified low density lipoprotein (LDL) that leads to foam cell formation has long been considered one of the requisite initiating events in atherogenesis. We sought to determine if IL10 exerts its anti-atherogenic effect by modulating lipid metabolism in the macrophage.

Methods & results
In lipid uptake studies, IL10 substantially stimulated Dil-acetylated (Ac)LDL uptake by 187% in murine macrophage-like RAW264.7 cells. IL10 induced the expression of SR-AII and CD36 by 15.1 fold and 6.5 fold, respectively, in macrophage-derived foam cells. Moreover, CD36 protein levels were increased by IL10, suggesting that these scavenger receptors account, at least in part, for the increase in modified LDL uptake by the macrophages. Accordingly, IL10 treatment for 24hr significantly increased cholesteryl ester content by 1.5 folds compared with untreated controls (p<0.05). Interestingly, IL10 also markedly promoted ATP-binding cassette protein A1 (ABCA1)-mediated free cholesterol efflux to lipid-free apoAI acting as a cholesterol acceptor. This was peroxisome proliferator-activated receptor (PPAR)γ-dependent because specific PPARγ antagonist GW9226 completely blocked the IL10-triggered cholesterol efflux to lipid-free apoAI. In addition, expression of pro-inflammatory molecules such as TNFα, MCP-1 and iCAM-1 was dramatically inhibited by IL10 in the lipid-laden foam cells. Using immunofluorescence assay of caspase 3 fragment and TUNEL assay, we demonstrated that IL10 significantly suppressed apoptosis of foam cells (27.3 ± 2.1% for AcLDL-treated cells vs. 8.3 ± 1.0 %for AcLDL plus IL10-treated cells, n=8).

Conclusion
Our results indicate that IL10 can mediate both the uptake of cholesterol from modified LDL and the efflux of stored cholesterol. Therefore, IL10 may facilitate the removal of harmful atherogenic lipoprotein molecules from the vessel wall. These characteristics along with its ability to suppress the expression of inflammatory molecules and apoptosis of foam cells make IL10 a highly anti-atherogenic agent.
Abstract 130: CD4 T Cell Dysfunction Induced to Endothelial Apoptosis in Peri-menopausal Women with Low Estrogen levels
Authors: Gomita Keiko , Sato Kayoko , Nuki Toshiaki , Suzuki Yuki , Hagiwara Nobuhisa , Kasanuki Hiroshi
Published: July 2021

Background
: Plaque erosion is responsible for the majority of acute coronary thrombi and induces acute coronary syndromes (ACS) in perimenopausal women. However, the causal relationship between low estrogen levels and plaque erosion mechanism in perimenopausal women is not fully understood. We examined whether perimenopausal women (PMW) with low levels of estrogen have had T cell dysfunction, and whether they experienced accelerated plaque erosion as a result.

Methods and Results
: Fresh CD4 T cells were isolated from 45 PMW within 5 years after menopause (mean age 53.9 ± 6.0 years) and 40 women with regular menstruation cycles (NC, mean age 34.0 ± 7.4 years). Estrogen levels in plasma were lower in PMW than NC (P < 0.0001). Estrogen receptor α (ESR1) and estrogen receptor β (ESR2) mRNA of CD4 T cells in PMW were lower compared to NC by real time PCR (P < 0.05). Estrogen levels correlated significantly with ESR1 transcripts (R = 0.537, P < 0.03). The inflammation marker of hsCRP was higher (P < 0.003) and CD69, an activation marker of T cells, had stronger expression on CD4 T cells from PMW by FACS (P < 0.04). Measurement of fragmentation of DAPI-binding nuclear proteins showed that CD4 T cells from PMW induce significant human umbilical vein endothelial cells (HUVEC) apoptosis compared to those from NC (P < 0.001). Furthermore, CD4 T cells from PMW expressed strong p-selectin glycoprotein ligand-1(PSGL-1) and integrin (CD18) but not L-selectin by FACS (P < 0.006, P < 0.05, n.s., respectively). Estrogen levels correlated negatively with PSGL-1 (R = 0.997, P < 0.05) and CD4 T cell-induced HUVEC apoptosis (R = 0.439, P < 0.0001). Treatment with 17β-estradiol showed reduction of CD4 T cell-induced apoptosis in PMW. Estrogen receptor antagonist ICI 172,780 abolished estrogen protection.

Conclusions
: From these results, we concluded that CD4 T cells in perimenopausal women were already activated and displayed dysfunctions related to deficiency of estrogen and estrogen receptors, which may be a factor that contributes to the acceleration of plaque erosion in atherosclerotic plaque and acute coronary syndromes.
Abstract 257: Oxidative Stress Induces Endothelial Dysfunction: Role of Ubiquitin-Proteasome System
Authors: Xu Jian , Wang Shuangxi , Wu Yong , Song Ping , Zhang Miao , Zou Ming-Hui
Published: July 2021

Endothelial Nitric oxide (NO) production is dependent on adequate cellular tetrahydrobiopterin (BH
4
), a key cofactor for endothelial NO syntheses (eNOS). Reduction of BH
4
levels is reported in diseased vessels and plays a causal role in the development of eNOS uncoupling. However, the mechanisms that lead to BH
4
reduction are not entirely understood. Here we report that angiotensin-II (Ang II) reduced tetrahydrobiopterin (BH
4
) and eNOS uncoupling by peroxynitrite ONOO
−
)-triggered proteasome activation. Compared to control, exposure of human umbilical vein endothelial cells (HUVEC) to angiotensin II (Ang II, 100nM) for 6h significantly decreased the levels of total biopterins (BH
4
plus BH
2
) and BH
4
(−22.0 4.6%, n= 3, p<0.01), indicating decreased synthesis of biopterins. In parallel, Ang II but not vehicle significantly reduced the levels of GTP-cyclohydrolase (GTPCH), a rate-limiting enzyme for de novo synthesis of biopterins, and dihydrofolate reductase (DHFR), a crucial enzyme for BH
4
recycle from BH
2
. Ang II but not vehicle significantly increased the 26S proteasome activity. In addition, administration of proteasome inhibitors, MG132, abolished the Ang II-induced reduction of both GTPCH and DHFR. While Ang II significantly increased O
2
−
, the scavenging of O
2
−
by Tempol (SOD mimetic), or inhibition of NOS with
N
-nitro-L-arginine methyl ester hydrochloride (L-NAME) (1mM) significantly attenuated Ang II-induced both 26S proteasome activation and the reduction of both GTPCH and DHFR, suggesting that Ang II via endogenous ONOO
−
causes 26S proteasome-dependent degradation of both GTPCH and DHFR. Moreover, inhibition of NAD(P)H oxidase with either apocynin or by overexpression of p67
phox
-dominant negative mutants ablated Ang II-induced proteasome activation and degradation of both GTPCH and DHFR. Finally, treatment of mice aorta
ex vivo
with MG132 (0.5 μM for 1h followed by Ang II for 12h) reversed the Ang II-induced reduction of GTPCH, DHFR and BH
4
, and increased acetylcholine-induced endothelium-dependent relaxation. We conclude that Ang II activates NAD(P)H oxidase to release O
2
. −
and ONOO
−
, which activate 26S proteasome resulting in increased degradation of both GTPCH and DHFR, two key enzymes in controlling the levels of BH
4
.
Abstract 1505: Sunitinib-Induced Cardiotoxicity is Mediated in Part via Direct Effects on Cardiac Myocytes and Smooth Muscle Cells
Authors: Dallabrida Susan M , Ismail Nesreen , Pravda Elke A , Cassiola Flavia , Kim Sendia , Parodi Emily M , Kerkela Risto , Force Thomas , Puder Mark , Rupnick Maria A
Published: July 2021

Tyrosine kinase inhibitors (TKI) have revolutionized cancer therapy, spawning over 500 clinical trials, yet cardiotoxicities are emerging. Sunitinib, a multi-targeted TKI, prolongs life in renal cell and gastrointestinal cancer patients, but hypertension and heart failure have required treatment adjustments.

Objective:
Sunitinib cardiotoxicity may be due, in part, to direct effects on smooth muscle and cardiac myocytes.

Methods:
We used C57Bl/6J mice, rat neonatal cardiomyocytes (NCM), and human coronary artery smooth muscle cells (SMC) treated with Sunitinib to measure drug-induced cardiovascular toxicity. Structural (transmission electron microscopy, immunohistochemistry (IHC)/confocal microscopy) and functional [apoptosis/survival, nitric oxide synthesis (intracellular and extracellular), signaling] effects were assessed [real-time PCR, Western blotting, receptor phosphorylation (immunoprecipitation/Western blotting)].

Results:
We show mitochondrial injury in hearts from Sunitinib treated mice which persisted off of the drug.
In vitro
, Sunitinib accumulated in myocytes, caused myofibrillar disorganization, mitochondrial injury, and localized to the lysosomes. Sunitinib caused reductions in akt, MAPK, and AMPK signaling, and activated pro-apoptotic caspase-9 in NCM and SMC with similar effects in large and small vessel endothelial cells. In hearts of Sunitinib-treated mice, we found similar changes in signaling pathways.

Conclusion:
Sunitinib causes direct cardiac myocyte and smooth muscle cell toxicities, which may contribute to the cardiovascular side effects seen in patients. Further understanding of these mechanisms will guide monitoring, intervention and future rational drug design.
Abstract 1513: Short And Long-term Mortalitty In Chest-Pain Patients Ruling-in For Myocardial InfarctionI: STEMI Versus Non-STEMI In The Era Of A Troponin-based Definition For MI
Authors: Kontos Michael C , Noel Thomas T , Roberts Charlotte S , Anderson F Philip , Tatum James L , Ornato Joseph P , Jesse Robert L
Published: July 2021

Background:
Several randomized clinical trials have demonstrated that patients (pts) with ST Elevation myocardial infarction (STEMI) have a higher short-term mortality than those with non-STEMI, but that long-term mortality is similar. More recent studies suggest that pts who are troponin positive (TnI+), but not meeting the older CKMB criteria for MI may also be at increased risk. However, there is little data examining outcomes differentiating these 3 MI populations using the current ACC/ESC definition for MI selected from a heterogeneous cohort of pts admitted from the emergency department.

Methods:
Consecutive pts admitted for exclusion of myocardial ischemia underwent serial sampling of CK, CKMB, and TnI. MI was defined using ACC/ESC criteria. Pts were separated into 3 groups: STEMI (n=363; 22%), non-STEMI pts who met the prior CKMB criteria for MI (n=743; 46%), and non-STEMI pts who had MI based on TnI (+) alone (n=512; 32%) without meeting CKMB MI criteria. Demographic and clinical variables were compared among the three cohorts of patients, and 30 day and 1 year mortality were assessed.

Results
: Over a 6 year period, 1,618 pts were diagnosed with MI. Co-morbidities and outcomes are shown below in the table

. Variables associated with worse outcomes were significantly more common in both groups of non-STEMI pts, particularly in the TnI (+) only pts. Thirty day mortality was similar and not significantly different among the 3 cohorts. However, at 1 year, mortality was a significant 68% higher in the 2 non-STEMI groups, despite having significantly lower peak CK (median 123 U/L for TnI (+) pts and 414 U/L for CKMB MI pts vs 1400 U/L for STEMI pts) and CKMB values (median 4 ng/ml for TnI (+) pts and 29 ng/ml for CKMB MI pts vs 140 ng/ml for STEMI pts) compared to STEMI pts.

Conclusions
: All MI pts had similar 30 day mortality; however, at 1 yr pts with non-STEMI had a substantially increased mortality compared to STEMI pts.
Abstract 1540: Weather/Temperature Change and Heart Disease
Authors: Chase-Ziolek Andrew , Carlsen Jeremy , LeRoy Dawn , Holm Karyn
Published: July 2021

STUDY OBJECTIVE: Although recent studies have examined the effect of weather on acute coronary syndrome and heart failure, few have examined the influence of extreme weather and rapid temperature change on emergency department admissions for acute coronary syndrome and heart failure,

METHODS: We reviewed presentations of acute coronary syndrome (n = 2381) and heart failure (n = 1802) for the years 2003 to 2006 at an urban Level I Trauma Center and Accredited Chest Pain Center, examining presentation frequency on the warmest and coldest days of their respective years. In addition, we examined the frequency of presentation on days where the absolute difference between the mean temperature of one day and the next differed by 5, 10, and 15 degrees Fahrenheit. For each of these sample sets, we analyzed the data by gender and age.

RESULTS: Frequency of presentation did not significantly change on the hottest and coldest days of the year for acute coronary syndrome (p = 0.89 hot, p = 0.63 cold) or heart failure (p = 0.51 cold, p = 0.66 hot). No significant correlation was noted between gender and temperature extremes for acute coronary syndrome (p = 0.71 cold, p = 0.62 hot) or for heart failure (p = 0.83 cold, p = 0.59 hot). Age was not significantly correlated with temperature extremes for presentations of acute coronary syndrome (p = 0.72 cold, p = 0.63 hot) or heart failure (p = 0.95 cold, p = 0.99 hot). Changes in presentation frequency for either acute coronary syndrome (ACS) or heart failure (HF) at ΔT = 5°F were not significant (p = 0.70 ACS, p = 0.67 HF), nor were they significant at ΔT = 10°F (p = 0.97 ACS, p = 0.26 HF) or ΔT = 15°F (p = 0.17 ACS, p = 0.57 HF).

CONCLUSIONS: In theses patients, no significant correlations were noted between extreme weather events, temperature change and the presentation of acute coronary syndrome. In addition, no significant correlations were found between temperature differentials of 5, 10, or 15 °F and a diagnosis of acute coronary syndrome or heart failure.
Abstract 1568: Loss of Ischemic Postconditioning in the Mouse Hearts Lacking Adenosine A
1
or Bradykinin B
2
Receptors
Authors: Xi Lei , Das Anindita , Zhao Zhi-Qing , Merino Vanessa F , Bader Michael , Kukreja Rakesh C
Published: July 2021

Background:
Ischemic postconditioning (PostC) is a recently described cardioprotective modality against reperfusion injury, through a series of brief episodes of reperfusion/ischemia at the very onset of reperfusion. It has been well recognized that PostC can activate cellular signaling cascade, in which the role of G protein-coupled membrane receptors serving as upstream triggers of PostC remains to be established. Hence the goal of this study was to determine a definitive role of adenosine A
1
receptors (A1) and bradykinin B
1
or B
2
receptors (B1 or B2) in PostC, using gene knockout (KO) mice.

Methods & Results:
The hearts isolated from adult male C57BL/6J wild-type mice (C57-WT) or A1, B1, or B2 KO mice (n=7–9 per group) were subjected to 20 min of zero-flow global ischemia and 30 min of reperfusion with or without PostC in a Langendorff isolated, buffer-perfused heart model. PostC, consisted of 6 cycles of 10 sec of reperfusion and 10 sec of ischemia, significantly reduced myocardial infarct size (22.8±3.1%, Mean±SEM) as compared with C57-WT controls (35.1±2.8%, P<0.05). As shown in Figure

below, the infarct-limiting protection of PostC was absent in A1-KO (34.9±2.7%) or B2-KO (33.3±1.7%) and was partially attenuated in B1-KO (25.6±2.9%) mice, as compared with the corresponding non-PostC controls under same genetic background (P>0.05). However, cardiac contractile function and coronary flow at the end of reperfusion were not significantly altered by PostC.

Conclusion:
PostC-induced infarct size reduction in globally ischemic mouse hearts is triggered by activation of multiple G protein-coupled membrane receptors, which include A1, B2, and, to a lesser extent, B1 receptors.
Abstract 1581: Longitudinal 2-dimensional Strain Of Left Ventricle At Rest Predicts High Risk Coronary Artery Disease Without Regional Wall Motion Abnormality
Authors: Choi Jin-Oh , Park Seung Woo , Yang Jeong Hoon , Cho Sung Won , Cho Soo Jin , Lee Sang Yeub , Park Yong Whan , Lee Sang-Chol , Sung Jidong , Kim June Soo , Park Jeong Euy
Published: July 2021

Objectives:

Left main (LMD) and 3-vessel disease (3VD) are well-known risk factors for diagnostic stress test for coronary artery disease (CAD). However regional wall motions in those patients are frequently normal at resting status. We aimed to evaluate the segmental and global peak systolic longitudinal strain (PSLS) of left ventricle (LV) by 2D speckle tracking method and its usefulness as a screening method for high risk CAD.

Methods:

A total of 100 patients who underwent echocardiography and coronary angiography (CAG) were evaluated. Patients with regional wall motion abnormalities (RWMA), LV ejection fraction (EF) <50%, valvular heart disease, atrial fibrillation or poor images were excluded. Echocardiographic examination including 2D strain analysis was performed and patients were grouped according to the results of CAG as following; LMD or 3VD as high risk group, 1- or 2-vessel disease as low risk group, and normal group. The global and segmental PSLS of basal, mid and apical LV were analyzed offline.

Results:

The PSLS of every segment of LV could be obtained successfully with good tracking quality in 88 (88%) patients. There were no significant differences in age, sex, blood pressure, and LV EF (

See Table

). The global and segmental PSLS of LV was significantly lower in high risk group compared with normal group. The mean PSLS of basal and mid LV was significantly reduced in high risk group compared with other groups. The receiver operational characteristic (ROC) curve demonstrated that the mid and basal PSLS could effectively predict high risk group (area under ROC curve=0.84, 95%CI=0.76~0.92). According to the ROC curve, −17.9% may be an optimal operational cut-off level to discriminate high risk group from others (specificity 79%, sensitivity 83%).

Conclusions:

Longitudinal 2D strain of LV at rest is significantly reduced in high risk CAD without RWMA and it might be useful for prediction of high risk before stress test.

Clinical characteristics and peak systolic longitudinal strain
Abstract 1590: Association Between Arterial Stiffness, Coronary Microcirculation And Left Ventricular Function In Patients With Newly Diagnosed Arterial Hypertension.
Authors: Ikonomidis Ignatios , Lekakis John , Paraskevaidis Ioannis , Triantafyllidi Helen , Papadopoulos Costas , Georgoula Georgia , Kremastinos Dimitrios T
Published: July 2021

Arterial stiffness is an independent marker of cardiovascular morbidity and mortality. Coronary microcirculation is impaired in patients with arterial hypertension. We investigated the relationship between arterial stiffness, coronary microcirculation and left ventricular (LV) systolic and diastolic function.

METHODS: 80 untreated consecutive patients (mean age: 55±11 years 38 males), with newly diagnosed arterial hypertension and 20 healthy controls matched for sex, age and atherosclerotic factors, were studied. We measured a) Carotid to femoral artery pulse wave velocity (PWV) using the Complior apparatus b) Peak Systolic (Vs) and diastolic (Vd) coronary blood flow velocity, Vd/Vs ratio, Deceleration Time (DT-Vd) and time integral (VTI-Vd) of Vd using a 7MHZ transducer by means of colour-guided Doppler echocardiography at the distal tract of the LAD c) Ratio of VTI-Vd after adenosine infusion (140 μ g/kg/min) to VTI-Vd at baseline to assess coronary flow reserve (CFR) d) E and A doppler, Em, Am mitral annulus velocities TDI and E/Em ratio to assess LV diastolic function d) Mean Longitudinal, Transverse, Circumferential and Radial Strain and Strain Rate by 2-D Strain to assess LV systolic function.

RESULTS: Patients and controls had normal ejection fraction. Compared to controls, patients with hypertension had higher PWV (10.4±1.7 vs. 8.2±1.4 m/s, p<0.001), E/Em (8.3±2.8 vs. 5.7±1.4, p=0.001) and lower CFR (2.6±0.6 vs. 3.4±0.7, p<0.001), Vd/Vs (1.78±0.31 vs. 1.97±0.38, p=0.04), DT-Vd (973±226 vs 1113±332 ms, p<0.001), Em/Am (0.93±0.42 vs. 1.6±0.51, p<0.001), mean longitudinal strain (−17.8±3 vs. −19.8±3.1%, p=0.031) and mean circumferential strain ( −19.6±4.5 vs. −22±3.4 %, p=0.04). Increasing PWV was related to increasing E/Em (r=0.26, p=0.045) and decreasing CFR (r=−0.68, p<0.001). Increasing E/Em was related to decreasing Vd/Vs (r=−0.3, p<0.005) and CFR (r=−0.32, p=0.002).

CONCLUSIONS: Patients with arterial hypertension present subclinical systolic LV dysfunction and significant LV diastolic dysfunction compared to healthy controls. Increased LV diastolic filling pressures caused by arterial stiffness may increase the resistance of myocardial microcirculation leading to impaired coronary flow
Abstract 1648: Agreement and Disagreement between Contrast-Enhanced Magnetic Resonance Imaging and Nuclear Imaging for Assessment of Myocardial Viability
Authors: Roes Stijntje D , Kaandorp Theodorus A , Henneman Maureen M , Ajmone Nina , Westenberg Jos J , Stokkel Marcel P , Lamb Hildo J , van der Wall Ernst E , de Roos Albert , Bax Jeroen J
Published: July 2021

Purpose
To determine the agreement between contrast-enhanced MRI (ce-MRI) and nuclear imaging for assessment of viability in patients with severe ischemic LV dysfunction.

Methods
Patients (n = 25) with severe ischemic LV dysfunction (EF 25 ± 11%) were studied with cine MRI, ce-MRI,
99m
Tc-tetrofosmin single photon emission computed tomography (SPECT) and
18
F-FDG SPECT. Using a 17-segment model, each segment was assigned a wall motion score (0: normokinesia to 4: dyskinesia) and a scar score (0: no infarction to 4: 76–100% transmurality). Furthermore,
99m
Tc-tetrofosmin and
18
F-FDG segmental tracer uptake was categorized (0: tracer activity > 75% to 3: tracer activity < 25%). Dysfunctional segments were classified into viability patterns assessed with SPECT: normal pattern (normal perfusion and metabolism), mismatch (decreased perfusion, increased metabolism), mild match (mild decrease in perfusion and metabolism), and severe match (severe decrease in perfusion and metabolism). Difference in scar score between viability patterns was assessed using one-way ANOVA analysis.

Results
Of all analyzed segments (n = 425), 289 (68%) showed abnormal wall motion. Mean scar score was 0.3±0.7 in segments with a normal viability pattern, 1.0±1.2 in mismatch, 1.3±1.0 in mild match and 2.7±1.0 in severe match (p<0.001 between all patterns, NS between mismatch and mild match). The relation between MRI and SPECT is presented in Figure 1

.

Conclusion
Agreement between MRI and nuclear imaging for assessment of viability is high in segments with transmural scar on ce-MRI. However, non-enhanced tissue on ce-MRI can represent normal or jeopardized (perfusion-metabolism mismatch) myocardium.
Abstract 1690: Prevention of Contrast-Induced Nephropathy by Carperitide
Authors: Morikawa Shuji , Sone Takahito , Tsuboi Hideyuki , Mukawa Hiroaki , Morishima Itsuro , Uesugi Michitaka , Takagi Kensuke , Niwa Toru , Izumi Yusuke
Published: July 2021

Introduction: Contrast-induced nephropathy (CIN) remains as a common complication of angiographic procedure. Carperitide, an antagonist of secretion of rennin, aldosterone and vasopressin with natriuretic effects, has renal protective effects.

Hypothesis: Carperitide may be effective in preventing CIN.

Methods: We prospectively studied 170 consecutive patients with chronic renal failure (serum creatinine(SCr) concentration >1.3mg/dl)who underwent coronary angiography. The patients were randomly assigned to either 1.3ml/kg/hr of lactated Ringer’s infusion plus carperitide 0.042μg/kg/min (Carperitide group N=86) or lactated Ringer’s infusion alone (Control group N=84). The administration was initiated 6 hours prior to the procedure and continued for 48 hours after angiography. The concentration of SCr and cystatin C were measured at baseline, 24 hours, 48 hours, 1 week, and 1 month following the angiography.

Results: The SCr concentration increased gradually up to one month in the Control group, whereas remained almost unchanged in the Carperitide group (p=0.001 for the trend, Figure

). The cystatin C concentration also showed the same trend (p=0.013 for the trend, Figure

). When CIN was defined as an increase of ≥0.5 mg/dl or ≥25% in the SCr at 48 hours after angiography, CIN developed in 7 of 84 patients (8%) in the Control group and 1 of 86 patients (1%) in the Carperitide group (P=0.047). Multivariate analysis disclosed that carperitide infusion (OR 0.097, P=0.041) and quantity of contrast media (OR 14.06, P=0.004) were significantly related to the development of CIN.

Conclusions: Carperitide is effective in preventing CIN in patients with chronic renal failure.
Abstract 1694: Reduced Incidence of Contrast Induced Nephropathy after Percutaneous Coronary Intervention with Routine Use of Visipaque in Unselected Patients
Authors: Eichhöfer Jonas , Ivanov Joan , Osten Mark , Mackie Karen , Dzavik Vladimir
Published: July 2021

Objective:
An observational study to determine if the routine use of Visipague contrast solution was associated with a decreased incidence of contrast-induced nephropathy (CIN) in patients following PCI at a large, tertiary cardiac centre.

Methods:
The Toronto General Hospital Interventional Cardiology Program maintains a prospective registry of all PCI procedures12951 consecutive patients undergoing PCI from a prospective data registry were assigned to either Period 1 (2000 – 03, various contrast agents were utilized) or Period 2 (2003– 06, only Visipaque was used). The contrast agent was changed systematically to the iso-osmolar agent, Visipaque. CIN was defined as an increase in plasma creatinine of >25% within 24 hours following PCI. Using propensity scores, 2502 consecutive patients undergoing PCI in Period 1, were randomly matched to 2502 patients in Period 2. Multivariate logistic regression analysis was used to identify the independent predictors of CIN.

Results:
The two well matched cohorts showed no significant differences in major pre-procedure clinical variables. Visipaque was associated with a lower rate of CIN after PCI (Period 1 = 14%, Period 2 = 7%, p<0.001). The multivariate independent predictors of CIN were: Visipaque (OR 0.437, p<0.001), contrast media volume per 10 ml (OR 1.015; p<0.0001), pre-procedure creatinine per 10mmol/L (OR 1.013; p=0.003), ACS (OR 2.861; p <0.001), PCI following thrombolysis (OR 1.952; p=0.022), peripheral vascular disease (OR 1.375; p=0.023), and age per decade over 40 (OR 1.143; p=0.001)

Conclusions:
After adjusting for significant predictors of CIN, a strategy of routine use of an iso-osmolar contrast agent (Visipaque) appeared to be associated with a lower risk of developing CIN after PCI, especially in higher risk patients. Contrast volume, ACS and age were the most powerful predictors of development of contrast nephropathy.
Abstract 282: Endothelial-specific Deletion of Inhibitor of Kappa-B Kinase-β (IKK-β)
Authors: Ashida Noboru , SenBanerjee Sucharita , Kodama Shohta , Spencer Joel A , Zamiri Parisa , Li Ling , Gerszten Robert E , Lin Charles P , Karin Michael , Rosenzweig Anthony
Published: July 2021

The serine-threonine kinase, IKK-β, is required for classical activation of the NF-κB family of transcription factors which are central regulators of inflammation and cell survival that are activated in a variety of vascular diseases.

[Methods and Results]: To examine the role of IKK-β and NF-κB in endothelial cells (EC), we generated mice with EC-specific deletion of IKK-β (IKK-β
ΔEC
) on an ApoE
−/−
background using Tie2-Cre transgenic and IKK-β
flox/flox
mice. IKK-β
ΔEC
were born at less than the expected Mendelian frequency (7/48 vs 24/48 expected, p<0.0001) and were ~25% smaller than Cre-negative littermates (p<0.003). Vascular permeability assessed by
in vivo
microscopy of ear capillaries after intravenous injection of Evans blue dye was substantially increased (p<0.04). Several IKK-β
ΔEC
phenotypes were similar to Akt1
−/−
mice, prompting us to examine Akt1 in the IKK-β
ΔEC
mice. Interestingly, phospho-Akt was markedly reduced in vascular endothelium from IKK-β
ΔEC
mice.
In vitro
studies of primary cultured EC demonstrated that deletion of IKK-β inhibited phosphorylation of Akt and increased permeability, while overexpression of either wild-type (WT) or kinase-deficient (KD) IKK-β enhanced Akt phosphorylation. Immunoprecipitation experiments demonstrated IGF-I-enhanced physical interaction of IKK-β with Akt. Moreover, IKK-β deletion inhibited Akt trafficking to lipid rafts rich in caveolae, an essential step in its activation. Expression of either WT or KD IKK-β in IKK-β-deleted EC
in vitro
restored normal Akt trafficking and reduced endothelial permeability. These results are in contrast to those reported with deletion of IKK-β in hepatocytes which have relatively few caveolae.

[Conclusion] These data demonstrate that IKK-β modulates Akt subcellular trafficking and activation in EC through a kinase-independent mechanism. Understanding interactions between these signaling pathways may provide important insights in conditions marked by disregulated inflammation and/or cell survival including atherosclerosis and ischemic-injury.
Abstract 1724: Elevated Levels of the Atherosclerotic Lesion Metalloproteinase PAPPA Are an Independent Predictor of Cardiovascular Death or CHF in STEMI: Results from the CLARITY-TIMI 28 Biomarker Study
Authors: Sabatine Marc S , Morrow David A , Jiang Songtao , Rifai Nader , Cannon Christopher P , Gerszten Robert E
Published: July 2021

Background
: Pregnancy associated plasma proteinase A (PAPPA) is a metalloproteinase found in unstable atherosclerotic lesions. The prognostic value of PAPPA in ST-elevation myocardial infarction (STEMI) is unknown.

Methods
: We measured circulating PAPPA levels using an ELISA (Diagnostic Systems) in a case-cohort of 731 STEMI pts undergoing lysis in CLARITY-TIMI 28 and followed for 30 d. Multivariable Cox proportional hazards regression was used to adjust for demographics, comorbidities, infarct location, Killip class, and type of lytic.

Results
: The median level of PAPPA was 1.67 mIU/ml (IQR 0.18–9.89 mIU/ml). Patients with higher levels of PAPPA were more likely to be male, but tended to be less likely to have hypertension or diabetes, have an anterior MI, or present in Killip class II–IV. After multivariable adjustment, patients in the top 3 quartiles were at significantly higher risk for cardiovascular death or heart failure (Figure

, left, P=0.03). PAPPA levels were not correlated with other biomarkers of death or CHF, including NT-proBNP and ST2 (r<0.10 for both). In a multivariable model that adjusted for clinical covariates, all 3 biomarkers were independent predictors of CV death or CHF (Figure

, right, P<0.02 for each) and their addition to clinical risk factors significantly raised the c-statistic from 0.74 to 0.80 (P=0.003).

Conclusion
: Circulating levels of PAPPA at presentation are a significant predictor of a threefold increased risk of CV death or CHF in patients with STEMI. In a multimarker model, PAPPA, NT-proBNP, and ST2 were significant and complementary predictors of risk, and their addition to clinical risk factors significantly improved the c-statistic.

Risk for CV Death or CHF