bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 5440: Klf2 Inhibits Hif-1α Expression and Function in the Endothelium
Authors: Kawanami Daiji , Lin Zhiyong , Mahabaleshwar Ganapati , Atkins G. B , Hamik Anne , Haldar Saptarsi , Maemura Koji , Lingrel Jerry , Jain Mukesh
Published: July 2021

Introduction: Hypoxia-inducible factor 1 (HIF-1) is a central regulator of the hypoxic response in many cell types. In endothelial cells, HIF-1 induces the expression of key pro-angiogenic factors such as vascular endothelial growth factor (VEGF) to induce new blood vessel formation. Recent studies have identified Kruppel-like Factor 2 (KLF2) as a potent inhibitor of angiogenesis. However, the role of KLF2 in regulating the expression and function of HIF-1 has not been evaluated.

Hypothesis: KLF2 inhibits HIF-1α expression and function.

Methods and Results: Adenoviral overexpression of KLF2 in human umbilical vein endothelial cells (HUVECs) inhibited hypoxia-induced expression of HIF-1α, VEGF secretion, and matrigel tube formation. Conversely, siRNA-mediated knockdown of KLF2 in HUVECs increased HIF-1α expression and VEGF secretion. Consistent with this observation, KLF2−/− mouse embryonic fibroblasts (MEFs) showed accelerated HIF-1α accumulation in response to hypoxia and a marked induction of VEGF secretion (90.4±7.4 pg/ml in KLF2+/+ versus 234.6±6.1 pg/ml in KLF2−/−, p<0.01). From a mechanistic standpoint, KLF2-mediated reduction of HIF-1α level was attenuated by three distinct proteasome inhibitors (MG132, ALLN, or lactacystin), demonstrating that KLF2 mediated reduction of HIF-1α protein was proteasome-dependent. In addition, KLF2 maintained its ability to inhibit HIF-1α protein levels in VHL−/− cells, thermo-sensitive E1 deficient cells, and p53−/− cells. Finally, co-immunoprecipitation experiments revealed that KLF2 overexpression disrupted the interaction between HIF-1α and its chaperone Hsp90, suggesting that KLF2 promotes degradation of HIF-1α by affecting its folding and maturation.

Conclusions: These observations identify KLF2 as a novel inhibitor of HIF-1α expression and function through a VHL/p53 independent but proteasome dependent pathway. As such, KLF2 may be a target for modulating the angiogenic response in disease states.
Abstract 5441: The Roles for MicroRNA-221 and IGF-1 Signaling in Regulation of High Glucose-Induced Endothelial Dysfunction and Apoptosis
Authors: Li Yangxin , Song Yao-Hua , Li Fan , McNamara Kate , Geng Yong-Jian
Published: July 2021

Persistent hyperglycemia represents a major metabolic complication of diabetes, which may cause endothelial cell dysfunction and apoptosis. microRNAs are novel biomarkers, modulators and therapeutic targets for disease. The microRNA miR-221 is expressed in human umbilical vein endothelial cells (HUVEC). Insulin-like growth factor 1 (IGF-1) is an important survival factor for multiple cell types. This study was to investigate whether high glucose (HG) induces endothelial dysfunction and apoptosis through altering the microRNA expression and IGF-1 signaling. The mirVana qRT-PCR miRNA detection assay showed that exposure to glucose for 24 h dose-dependently (up to 25 mM) increased miR-221 expression by 2.6 ± 0.5 folds (p<0.05). HG treatment decreased c-kit protein expression (58 ± 7 % decrease vs. control at 48 h) assessed by flow cytometry. The treated HUVEC had a reduced capacity for wound healing responded to stem cell factor (SCF, the ligand of c-kit). SCF-induced HUVEC migration potential was also reduced significantly by exposure to high dose of glucose. As estimated by prediction algorithms, c-kit, but not IGF-1, was identified as the target of miR-221. Transfection of HUVEC with 2′-O-methyl antisense inhibitory oligonucleotide (AMO-221) downregulation of miR-221 led to attenuation of the glucose’s effect on the c-kit expression, SCF-induced migration and wound healing in HUVEC. Prolonged glucose exposure (25 mM, 96 h) induced apoptosis of HUVEC assessed by Death ELISA (O.D. values = 0.49 ± 0.06 in glucose group vs. 0.12 ± 0.07 in control, p<0.01). Addition of IGF-1 (30 ng/ml) blocked the glucose-induced apoptosis, whereas AMO-221 did not attenuate the apoptosis. In addition, the anti-apoptotic effects of IGF-1 was attenuated by PI3 kinase inhibitor LY294002 (15 uM) (IGF-1 + glucose + PI3 kinase inhibitor vs. IGF-1 + glucose = 0.45 ± 0.07 vs. 0.15 ± 0.05 O.D. values). Our data demonstrate that downregulation of miR-221 attenuates HG-induced reduction of c-kit, wound healing and migration of HUVEC, and enhanced IGF-1 signaling prevents HG-induced apoptosis. Thus, reducing miR-221 expression and activating IGF-1 signaling pathway may be a useful strategy to prevent diabetic-induced endothelial dysfunction and apoptosis.

This research has received full or partial funding support from the American Heart Association, AHA South Central Affiliate (Arkansas, New Mexico, Oklahoma & Texas).
Abstract 5448: Regulatory T Cells Control Post-Ischemic Neovascularization
Authors: Zouggari Yasmine , Ait-Oufella Hafid , Waeckel Ludovic , Vilar José , Loinard Céline , Cochain Clément , Recalde Alice , Duriez Micheline , Levy Bernard , Lutgens Esther , Mallat Ziad , Silvestre Jean-Sebastien
Published: July 2021

CD4+ and CD8+ T lymphocytes are key regulators of post-ischemic neovascularization. T cell activation is promoted by two major costimulatory signalings: the CD28/B7 and the CD40ligand-CD40 pathways. Interestingly, CD28 interactions with the structurally related ligands B7–1 and B7–2 are also required for the generation and homeostasis of CD4+CD25+ regulatory T cells (Treg), which play a critical role in the suppression of immune responses and the control of T-cell homeostasis. We hypothesized that Treg cell activation may modulate the immuno-inflammatory response to ischemic injury, leading to alteration of post-ischemic vessel growth. Ischemia was induced by right femoral artery ligation in CD28-, B7–1/2- or CD40-deficient mice (n=10 per group). CD40 deficiency did not affect Treg levels and led to significant reduction in post-ischemic inflammatory response and vessel growth. In contrast, at day 21 after ischemia, angiographic score, foot perfusion, and capillary density were increased by 2.0-, 1.2-, and 1.8-fold respectively in CD28-deficient mice, which show profound reduction in Treg, compared to controls. Similarly, disruption of B7–1/2 signaling and subsequent Treg deletion significantly enhanced post-ischemic neovascularization. These effects were associated with enhanced accumulation of CD3-positive T cells and Mac-3 positive macrophages in the ischemic leg of CD28−/− or B7−/− mice compared with controls. Proinflammatory cytokines, IL-1β, TNF-α and IL-6, were also upregulated and antiinflammatory mediators, IL-10 and TGF-β1 downregulated in the ischemic legs of CD28−/− or B7−/− mice. Finally, treatment of CD28−/− mice with the nonmitogenic anti-CD3 monoclonal antibody enhanced expression of the regulatory T-cell marker Foxp3 in blood and ischemic tissue of CD28−/− mice, led to reduction in post-ischemic inflammatory response and neovascularization in CD28-deficient mice. In conclusion, endogenous Treg cell response controls post-ischemic neovascularization.
Abstract 5451: Deficiency of Glutathione Peroxidase-3 Promotes Platelet Activation
in vivo
Authors: Jin Richard C , Mahoney Christopher E , Coleman Laura , Ottaviano Filomena G , Zhang Yingyi , Handy Diane E , Loscalzo Joseph
Published: July 2021

Plasma glutathione peroxidase (GPx-3) is a selenocysteine-containing protein with antioxidant properties. GPx-3 plays an important role in plasma against oxidant stress by scavenging reactive oxygen species. A deficiency of this enzyme has been associated with platelet dependent thrombosis. We recently developed an animal model to assess platelet function in GPx-3 deficient mice. We hypothesized that GPx-3 deficiency induces platelet activation
in vivo
. GPx-3 (−/−) mice showed an attenuated bleeding time compared with wild-type mice (94.5 ± 28.8 s versus 153.4 ± 32.3, P<0.05). We also noted an increase in the plasma levels of soluble P-selectin, a marker of platelet activation and prothrombotic activity, in GPx-3 (−/−) mice compared with wild-type mice (137.8 ± 12.3 ng/ml plasma versus 101.5 ± 8.8, P<0.05). Cyclic GMP, a key intracellular second messenger molecule and marker for activation of soluble guanylyl cyclase by nitric oxide, was decreased in the plasma of GPx-3 (−/−) mice compared with wild-type mice (5.38 ± 1.75 pmol/ml plasma versus 23.67 ± 3.59, P<0.001), consistent with less bioactive NO in GPx-3 (−/−) mice. ADP was infused into the right ventricle of mice to induce platelet aggregation in the pulmonary vasculature; this assay resulted in higher pulmonary artery pressure in GPx-3 (−/−) compared with wild-type mice suggesting a more robust platelet activation response in the GPx-3 (−/−) mice. To confirm this interpretation, histological sections from the pulmonary vasculature of GPx-3 (−/−) compared with wild-type mice showed increased thrombi per 7.5 mm
2
section normalized to wild-type mice based on staining intensity for P-selectin (1.7 ± 0.4 versus 1.0 ± 0.1, P<0.001), as well as a higher percentage of occluded vessels (0.82 ± 0.16 % versus 0.54 ± 0.21, P<0.05). These findings demonstrate that GPx-3 deficiency causes platelet activation resulting in a prothrombotic state. These data illustrate the importance of this plasma antioxidant enzyme in regulating platelet activity and platelet-dependent thrombosis.
Abstract 5478: P2Y
13
ADP-Receptor Regulates Plasma HDL Clearance, Biliary Cholesterol and Bile Acids Secretions In Vivo
Authors: Martinez Laurent O , Fabre Aurélie , Malaval Camille , Collet Xavier , Tercé François , Perret Bertrand , Boeynaems Jean-Marie , Ben Addi Abduelhakem , Robaye Bernard
Published: July 2021

Plasma high density lipoprotein (HDL) protects against atherosclerosis, in part through the removal of cholesterol from peripheral tissues and its delivery to the liver for metabolism and bile excretion. Thus understanding of the molecular event implicated in HDL-cholesterol uptake by the liver is critical to the development of therapeutic strategies to enhance HDL catabolism. The scavenger receptor (SR)-BI modulates plasma HDL level and contributes to cholesteryl ester uptake from HDL in mice but a distinct pathway for holo-HDL particle uptake (protein + lipid) has been recently identified in human hepatocytes. This pathway which strictly depends on extracellular ADP level involves different cell surface partners: ADP generated from the activation by apo AI (the main HDL apolipoprotein) of a cell surface F
1
-ATPase, activates the P2Y
13
ADP-receptor and subsequent HDL endocytosis through an unknown low-affinity HDL receptor. To evaluate the physiological relevance of this P2Y
13
-mediated HDL endocytosis pathway
in vivo
in mice, P2Y
13
receptor was activated by treating C57BL/6 and liver specific SR-BI-KO mice (SR-BI-KO
liver
) with the specific agonist (AR-C69931MX, 8nmol/kg, intra-orbital injection). Expression of P2Y
13
protein in liver was also disrupted by siRNA adenovirus (10
9
vp/mice, intra-orbital injection) and in P2Y
13
KO mice. Plasma clearance of
125
I-labeled HDL was rapidly enhanced under AR-C69931MX treatment in SR-BI-KO
liver
mouse. Conversely, HDL clearance was decreased in P2Y
13
KO mice but no modification was observed in plasma lipids profile
versus
control mice, suggesting a mechanism of modulation of plasma HDL turnover rather than a simply disruption of HDL uptake. Furthermore, biliary lipids content was decreased under P2Y
13
extinction in mice (bile acids: −60%, cholesterol: −30%), whereas it was dramatically increased under stimulation of P2Y
13
by AR-C69931MX treatment in C57BL/6 mice (bile acids: +85%, cholesterol: +50%,). These results indicate that P2Y
13
has an important role in hepatic HDL metabolism in controlling circulating HDL turnover and biliary lipids elimination, and thus may have an impact on the development of atherosclerosis.
Abstract 5517: A Novel Tissue Engineered Skeletal Muscle Screening Platform to Assess the Myotoxic Potential of Statins
Authors: Tiburcy Malte , Christalla Peter , Eschenhagen Thomas , Zimmermann Wolfram H
Published: July 2021

Our study had two objectives:

to develop a novel tissue engineered skeletal muscle drug screening platform and

to assess myotoxicity of various statins and identify underlying mechanisms.

Methods: Engineered skeletal muscle tissue (SMT) was generated from adult rat skeletal myoblasts, rat fibroblasts (1.25x106 cells/SMT), matrigel, and collagen. Reconstitution-mixtures (450 μl) were poured into circular moulds yielding ring-shaped constructs after 5 days. SMTs were cultured for additional 10 days on stretch devices and treated with increasing concentrations of statins or vehicle for the last 5 culture days. Force of contraction (FOC) was measured and SMTs subjected to either immune fluorescence (IF), HE-staining or Western blotting (WB).

Results: SMTs displayed differentiated muscle bundles (actin-IF and HE) and elicited tetanic contractions with maximal force at 60 Hz (1.3±0.2 mN; n=5). Carbachol (1 μM) induced a reversible block of muscle contraction which was antagonized by pancuronium (10 μM) indicating the presence and functionality of nicotinergic acetylcholine receptors. Statin treatment caused a concentration-dependent decrease in FOC in the following order of potency (EC50): cerivastatin (10 nM), simvastatin (100 nM), atorvastatin (350 nM), pravastatin (1860 nM; n=6–8/group and concentration). Contractile failure was paralleled by sarcomere breakdown and apoptosis (IF and WB: reduced actin, increased caspase 3). To assess the mechanism of statin myotoxicity, we investigated the protective effects of mevalonic acid (MEV, 100 μM), farnesyl-pyrophosphate (F-PP, 10 μM), squalene (S, 10 μM), and geranyl-geranyl-pyrophophate (G-PP, 10 μM) in the presence of maximally toxic cerivastatin concentrations (1 μM; complete contractile failure). MEV prevented cerivastatin toxicity completely (FOC: 102.3±16% of vehicle; n=7). GG-PP partially prevented cerivastatin-induced contractile failure (FOC: 53.3±14% of vehicle; n=4). S and F-PP had no protective effect (n=4/group).

Conclusion: SMT can be used to identify and compare statin myotoxicity in vitro and may be useful to dissect its underlying mechanisms. In addition, our data suggests that statin myotoxicity is at least in part independent of cholesterol depletion.
Abstract 5526: Genetic Variation at
PCSK5
Influences HDL-C Levels
Authors: Iatan Iulia , Dastani Zari , Do Ron , Bailey Swneke D. , Ruel Isabelle , Krimbou Larbi , Prat Annik , Seidah Nabil G. , Engert James C. , Genest Jacques
Published: July 2021

Low plasma HDL-C is a well-established risk factor for coronary artery disease. The role of endothelial lipase (EL) in HDL metabolism has been recently characterized. The proprotein convertase subtilisin/kexin 5 (PC5/6 or PCSK5) is known to inactivate both EL and lipoprotein lipase (LPL)
ex vivo
, enzymes critical in modulating plasma levels of HDL-C. In the present study, we investigated the role of human
PCSK5
genetic variants on HDL-C; in addition, we characterized lipoprotein fractions in
Pcsk5
+/−
mice, compared with wild type. Sequencing of the
PCSK5
gene was performed in 12 probands with low HDL-C (<5
th
percentile) and 7 novel non-coding genetic variants were found. We genotyped these SNPs along with 163 tag SNPs and 12 additional SNPs (n=182 total) selected from the HapMap Project, in 457 individuals with documented coronary artery disease. We identified 10 SNPs associated with HDL-C (p<0.05), with the strongest result being rs11144782 (minor allele frequency: 0.164, p=0.002). In an analysis of HDL-C as a dichotomous trait, 3 of the 10 SNPs were also associated with low HDL-C at either the 5
th
or the 10
th
percentile (p<0.05). The rare allele of rs111447782 decreased HDL by 0.076 mmol/L in a gene dosage-dependent fashion. We further investigated the effect of this SNP on other lipoprotein levels and identified an association with very low density lipoprotein (p=0.039), triglycerides (p=0.049) and total ApoB (p=0.022) levels. Furthermore, in conditional regression analysis, we identified 3 additional SNPs contributing to HDL-C (p<0.05), all independent of the effect of rs11144782. In addition, we characterized serum from
Pcsk5
KO mice. Serum from
Pcsk5
+/−
mice (
Pcsk5
−/−
is embryonic lethal) showed reduction in HDL-C by gel permeation chromatography on HPLC and size redistribution of HDL species by 1D and 2D PAGGE. These results, and the rs11144782 SNP result presented above, are consistent with the concept that PCSK5 modulates HDL, likely upstream of EL and LPL. We conclude that variability at the
PCSK5
gene locus influences HDL-C levels and consequently, atherosclerotic cardiovascular disease risk.
Abstract 557: The Utility of Serial Enzymes to Rule out Myocardial Injury in Pateints with Non-Critical Disease by CT Angiography
Authors: O’Neil Brian J , Medado Patrick , Wegner James , Gallagher Michael , Raff Gil
Published: July 2021

Coronary Computed Tomography Angiography (CCTA) is a diagnostic test shown to have a high negative predictive value for coronary artery disease and major cardiac events at three months. Many emergency department, (ED), protocols mandate serial enzymes prior to discharge to capture possible myocardial injury even with normal CCTAs. Determine the value of serial cardiac enzymes in low risk patients (TIMI Risk Score <3) presenting to the ED with chest pain who have a normal or intermediate CTA, (< 25% stenosis). 307 patients received CCTA as part of clinical trials. All patients presented to the ED with suspected acute coronary syndrome and had a TIMI Risk <3, non diagnostic ECGs and negative initial enzymes. All patients had serial enzymes sampling at least 4 hours apart per protocol. Structured telephone follow up and chart review was completed at 30 and 90 days post ED visit. All data was analyzed using descriptive statistics. 68% of all CTA patients were classified as normal < 25% stenosis, with another 8% considered intermediate < 50% stenosis. Average time between blood collection was 4:30+/−1:28. All patients had normal serial Troponin I values (Normal <0.05 ng/mL) with no appreciable delta over time. 39 patients had an increase in Myoglobin values with 10 having a delta ≥20% but <50%, none of these patients had a level above our normal range (< 98 ng/ml). Only one myoglobin values was above our normal limits, but did change over time. There were no deaths or adverse cardiac events at 90 days in this population. In this study of low risk patients with suspected cardiac ischemia (TIMI <3) and a normal or intermediate CCTA, serial cardiac enzymes have no utility.
Abstract 573: Relation between Admission Plasma Glucose and In-Hospital Mortality is Different between Diabetic and Non-Diabetic Patients with Acute Myocardial Infarction
Authors: Ishihara Masaharu , Kojima Sunao , Kosuge Masami , Kimura Kazuo , Ogawa Hisao
Published: July 2021

It has been well demonstrated that acute hyperglycemia is associated with high mortality after acute myocardial infarction (AMI). However, optimal plasma glucose (PG) level is not known. The relation between PG and mortality may be different between diabetic and non-diabetic patients. This study consisted of 3,750 patients who were admitted to the 35 hospitals participating to the Japanese Acute Coronary Syndrome Study (JACSS) group within 48 hours after the onset of AMI. PG was measured at the time of hospital admission. In non-diabetic patients, there was a linear relation between PG and in-hospital mortality. Non-diabetic patients with PG <6 mmol/L had the lowest mortality (2.5%). As PG increased by 1 mmol/L, mortality increased by 17% (13%–21%, p<0.001). However, in diabetic patients, there was a U-shape relation between PG and mortality (Figure

). Diabetic patients with PG 9–10 mmol/L had the lowest mortality (1.9%); both diabetic patients with PG <7 mmol/L (9.4%, p=0.009) and those with PG ≥11 mmol/L (9.1%, p<0.001) had significantly higher mortality than those with PG 7–11 mmol/L (3.2%). Diabetic patients with PG 9–10 mmol/L had the lowest mortality, whereas lower PG was better in non-diabetic patients. Optimal PG level may be different between diabetic and non-diabetic patients with AMI.
Abstract 650: Animal Study Results Support that Biometal Artificial Muscle Restores Atrial Kick and Could Replace Oral Anticoagulation in Permanent Atrial Fibrillation
Authors: Tozzi Piergiorgio , Hayoz Daniel , Salchli Francois , von Segesser Ludwig K
Published: July 2021

Treatment of persistent atrial fibrillation (AF) consists of ventricular rhythm control and the use of anticoagulant agents to decrease the high risk of stroke. However, patients under lifetime anticoagulation therapy are exposed to hemorrhagic stroke (1–3% patients/year). The best treatment to prevent stroke may induce stroke itself. Because decreased flow within the fibrillating atrium is associated with spontaneous echo contrast, thrombus formation and embolic events, any device able to restore the atrial kick (AK) should significantly reduce the risk of stroke and eventually improve cardiac output (CO). A motorless, volume displacement pump based on artificial muscle technology could reproduce the AK when placed onto a fibrillating atrium. This study has been designed to assess mechanical effects of this pump on the right cavities in an animal model of AF. Atripump (Nanopowers SA, Switzerland) is a dome shape silicone coated biometal actuator 5 × 45mm. The biometal is electrically actuated by a pacemaker like control unit. In 10 sheep the right atrium (RA) was surgically exposed and the dome sutured onto it. AF was induced with rapid epicardial pacing (600 beats/min). RA ejection fraction (EF) and spontaneous echo contrast was assessed with intracardiac ultrasound in baseline, AF and assisted AF status. A flow meter placed on pulmonary artery measured CO. Results The dome’s contraction rate was 60/min. Mean temperature on the RA was 39±1.5 °C. RA EF was 30% in baseline, 5% in AF and 22% in assisted AF conditions. During the AF state, spontaneous echo contrast was present in all animals and in 2 a thrombus appeared in the right appendix. Neither spontaneous echo contrast nor thrombi were present in baseline and AF assisted status. Thrombi were washed out when the pump was turned on. CO was 5.3±0.3 l/min in baseline, 4.4±0.6 l/min in AF and 5.1±0.3 l/min in assisted AF status (p<0.01). Placed on the right side, the artificial muscle restores the AK, improves CO and shows a mechanical anti coagulant effect. In patients with permanent AF, if implanted on both sides, it would improve CO and prevent embolism of cardiac origin. The implantation technique could be comparable to that of a pacemaker.
Abstract 654: Ventricular Arrhythmia Following Alcohol Septal Ablation for Hypertrophic Obstructive Cardiomyopathy: Clinical Predictors of Events
Authors: Noseworthy Peter A , Rosenberg Michael , Ruskin Jeremy N , Palacios Igor F , Mela Theofanie , Fifer Michael A , Das Saumya
Published: July 2021

Alcohol septal ablation (ASA) is a non-surgical alternative to septal myectomy for treatment of symptomatic, drug refractory hypertrophic obstructive cardiomyopathy (HOCM). The effect of ASA on the risk of ventricular arrhythmia (VA) is unknown. There is a theoretic concern for pro-arrhythmia at the site of myocardial injury. We examined the rates of sudden cardiac death (SCD) and VA (defined as VA requiring ICD therapy or documented VT/VF) among all 88 patients treated with ASA at Massachusetts General Hospital between 1998 and 2004. Of these patients, 37 had either an ICD or a permanent pacemaker
in situ
that enabled surveillance for VA events. Patients were classified as either high-risk (one of the following: VA or positive EP study, syncope due to suspected VA, family history of SCD, septal thickness ≥30mm by echocardiography, or failure to augment sBP >20mmHg on stress testing), or low-risk (no high-risk features). There was no mortality attributable to sudden cardiac death (mean follow up 35±21mo). The event rate for VA in low-risk patients was 3.0% per year (2/18 patients), and 6.3% annually among high-risk patients (4/16 patients). Device data were not available on three patients. In a stepwise Cox proportional hazards multivariate analysis that included pre-ASA arrhythmia, peri-ASA arrhythmia, pre-ASA gradient, change in gradient after ASA, peak CK-MB, and post-ASA gradient, only post-ASA gradient predicted future VA (HR 1.06, 95% CI 1.03–1.10, p <0.001). In this single center experience, ASA was not associated with SCD or with high rates of VA. The post-ASA gradient correlates with the risk of ventricular arrhythmia after ASA.
Abstract 694: More Extensive Left Ventricular Hypertrophy in Transthyretin-Type Cardiac Amyloidosis as Compared to Primary Light-Chain Cardiac Amyloidosis
Authors: Appelbaum Evan , Harrigan Caitlin , Manning Warren J , Ruberg Frederick L , Gibson Michael , Skinner Martha , Tripp Kenneth J , Packman Jeff , Grogan Donna
Published: July 2021

Background
: Cardiac amyloidosis is generally described as a disease with left ventricular (LV) wall thickening, but data supporting LV morphologic differences between types of amyloidosis are lacking. We sought to examine LV morphologic differences between patients with light chain (AL) and transthyretin (TTR)-type amyloidosis with cardiac involvement using volumetric cardiovascular magnetic resonance (CMR).

Methods
: Patients with proven AL (n =21) and TTR amyloidosis (n =14) underwent cine CMR using standard methods. Volumetric LV mass, LV volumes, and LV mass/volume ratio were measured by an independent core lab blinded to all patient data, using a contiguous short-axis stack of images covering the left ventricle.

Results
: Both groups demonstrated a male predominance (TTR 86%, AL 67%) with patients in the TTR group older than AL group (74±8yr vs 61 ± 12yr p=0.002). There were no differences in the degree of heart failure symptoms in the TTR and AL groups: NHYA Class I: 4 vs 5; Class II/III: 9 vs 15; Class IV: 0 vs 1, respectively (p=0.68). The maximum anteroseptal thickness was greater in the TTR group (17.9 ± 3.6mm vs. 14.1 ± 3.3mm; p<0.001). Left ventricular end-diastolic mass was also greater in TTR compared to AL amyloid (236 ± 63g vs. 186 ± 61 g; p=0.02) with no significant difference in LV end-diastolic volume (TTR: 154 ± 32 ml vs. 155 ± 45 ml; p=0.89). The LV mass to volume ratio for TTR amyloidosis was significantly greater than the AL group (1.58 ± 0.5 vs. 1.24 ± 0.4; p=0.02).

Conclusions
: These data demonstrate that LV morphology differs between TTR and AL cardiac amyloidosis, with increased wall thickness and mass in TTR despite similar baseline symptoms and clinical characteristics. Given the reported more aggressive course of AL vs. TTR cardiac amyloidosis, the clinical significance of these findings needs to be further evaluated.
Abstract 707: Nonuniformity of Left Ventricular Apical-to-Basal Diastolic Lengthening in Patients with Hypertrophic Nonobstructive Cardiomyopathy
Authors: Tanaka Takeo , Murata Kazuya , Akagawa Eizo , Kihara Chikage , Yoshino Hiroko , Nose Yoshio , Fukagawa Yasuhiro , Susa Takehisa , Okuda Shinichi , Wada Yasuaki , Matsuzaki Masunori
Published: July 2021

Quantification of left ventricular (LV) apex-to-base dispersion has been feasible with two-dimensional echocardiographic tissue tracking system (2DTT, Hitachi EUB7500), which based on pattern matching algorithm. Although impairment of LV relaxation was characterized in patients with hypertrophic cardiomyopathy (HCM), the behavior of LV apical and basal diastolic lengthening and its relation to LV filling are unknown. We obtained basal and apical LV short-axis views in 22 patients with non-obstructive HCM and 25 healthy volunteers (N). Eight equiangular points on endo-myocardium at end-diastole were placed in each view, and the shortening ratios of four directions were calculated and averaged by 2DTT. Then, the time-LV shortening and lengthening curves were obtained. The time intervals from the aortic valve closure to the point of the first 40% of peak lengthening (T
40
) were measured in each view. Isovolumic relaxation time (IRT) was measured by pulsed Doppler LV in- and out-flow recordings. Although both apical and basal T
40
were similar in N (145.8±38.4 vs. 134.3±34.2msec
0.5
, ns.), the apical T
40
in HCM was longer compared to base (118.7±51.1 vs. 168.8±52.5msec
0.5
, p<0.0001). The time difference of T
40
between apex and base was related to LV IRT (r=0.59, p<0.0001). Nonuniformity of apical-to-basal left ventricular lengthening during early diastole was present in HCM. This apex-to-base dispersion, especially apical delay in timing of LV lengthening may have a physiologic importance for impairment of LV relaxation in HCM.
Abstract 811: Natural History and Expanded Clinical Profile of Stress (Tako-Tsubo) Cardiomyopathy in United States Women
Authors: Sharkey Scott W , Windenburg Denise C , Hauser Robert G , Lesser John R , Maron Barry J
Published: July 2021

Stress cardiomyopathy (SC) is a newly reported condition of older women, triggered by emotionally and physically stressful events, characterized by acute heart failure with a distinctive angiographic profile, and regarded as a reversible process. To date, extended follow-up of SC patients is largely unavailable. We have assembled a substantial consecutive group of patients with SC to assess short and long-term clinical consequences of this condition. Between 2001–2008, we prospectively identified and followed (mean 2.0 years, range 0–6.7) 113 consecutive women with SC at a tertiary care United States hospital. Patients were female, aged 32–92 years (mean 68±13), and 16 (14%) were < 55 years. In 105 (93%) a triggering stressful event (emotional in 50, acute illness in 55) was identified; however, in 8 patients (7%) no such event preceded SC. The ECG showed ST-segment elevation in 58(51%) patients and ejection fraction (EF) was 31±11%. Troponin was elevated in 109 (96%); peak troponin (T) was 0.64±0.76 ng/ml. Of the 113 patients, 110(97%) survived the acute event: 3 patients (3%) died in-hospital (cardiogenic shock in 2; subarachnoid hemorrhage in 1). Other complications included: cardiac arrest 2 (2%), hypotension requiring inotropic drug and/or intra-aortic balloon pump in 22 (19%), pulmonary or cerebral embolism in 3 (3%), left ventricular (LV) or right ventricular thrombus in 7 (6%) and LV outflow obstruction in 13 (12%). CMR findings included absent delayed hyperenhancement (gadolinium) in 82/83 (99%), normal LV apical contraction in 46%, RV akinesia in 22%, and pleural effusions due to heart failure in 46%. At follow-up, EF returned to normal in all patients, but one or more SC events recurred in 7 (6%) patients (complicated by non-fatal cardiac arrest in 1), of whom 3 were taking beta-blockers. Post-hospital death occurred in 15 (13%) patients of which 14 were noncardiac and 1 of unknown cause. Among this large cohort of women, some SC events occurred atypically either without a stress trigger or in younger premenopausal patients. SC also led to death in the acute phase or to later non-fatal recurrences of SC or cardiac arrest in about 10%. Therefore, the clinical profile of SC is much broader than previously regarded.
Abstract 839: A Common Allele at the
GRB14
Locus is Associated with Increased Cardiovascular Risk in Type 2 Diabetes: Evidence from a Pooled DNA GWA Study
Authors: Xu Rui , Wojcik Joanna , Gervino Ernest V , Hauser Thomas H , Amundsen Celeste A , Powers Christine , Matthews Brian P , Warram James H , Doria Alessandro
Published: July 2021

Genetics factor have long been recognized as important modulators of the risk of coronary artery disease (CAD) in both the general and the diabetic population. Evidence from our group indicates that some of these genes may act synergistically with the diabetic milieu, resulting into an especially strong effect among diabetic individuals. To search the genome for variants having a major effect on CAD risk in type 2 diabetes (T2D), we conducted a 300K SNP genome-wide association (GWA) study using DNA pools made from 322 CAD-positive and 412 CAD-negative individuals with T2D of European origin from the Joslin Heart Study (JHS). SNPs associated with CAD were found to cluster on chromosomes 2q24, 5p14, 9p21, and 14q31. These association signals were confirmed by genotyping of individual DNA samples, with additive ORs in the 1.4–1.6 range. The signal on chromosome 9p21 corresponded to the CAD locus that had been identified in the general population in the vicinity of the
CDKN2A/CDKN2B
genes. Of the other three regions emerging from the GWA screen, chromosome 2q24 showed the strongest association with CAD. The most representative SNP at this location (rs631871, additive OR=1.53, 95%CI=1.24–1.88, p=7.5 × 10
−5
) was placed in the 3′ flanking region of the Growth Factor Receptor-Bound 14 (
GRB14
) gene, which codes for an adapter protein with inhibitory effects on insulin receptor signaling. A similar association was found between rs631871 and cardiovascular mortality in an independent group of 475 type 2 diabetic patients (mean age at baseline=57±10 y) who were recruited at the Joslin Clinic for genetic studies in 1994–1996. In this cohort, the cumulative 10-year cardiovascular mortality was 28.1% among homozygotes for the risk allele, 20.0% among heterozygotes, and 15.8% among homozygotes for the protective allele (age and sex adjusted additive HR=1.41, 95%CI 1.04–1.90, p=0.026). By contrast, the association with increased cardiovascular risk was not confirmed in this cohort for the signals on 5p14 and 14q31. These findings point to the insulin signaling inhibitor
GRB14
as a possible modulator of cardiovascular risk among individuals with T2D.
Abstract 861: Comparison of Three Different Doses of ACTH Stimulation During AVS For Primary Aldosteronism
Authors: Rossi GianPaolo , Seccia Teresa M , Miotto Diego , Mantero Franco , Pitter Gisella , Patalano Anna , Pessina Achille C
Published: July 2021

Background.
ACTH stimulation was proposed to overcome the potential biases associated with pulsatile aldosterone secretion during AVS. Different protocols and doses of synthetic ACTH have been used but no systematic comparison between them was available.

Aim.
To compare the effects of 3 different doses of ACTH on the selectivity (SI) and the lateralization index (LI).

Patients and Methods.
We prospectively tested the effect of a high dose (HD; 250 μg as an i.v. bolus, n=41), a very low dose (VLD, 250 pg as an i.v. bolus followed by 0.5 pg/min infusion, n=6) and an intermediate dose (ID 50 μg/hr; n=7) on the SI and LI in patient referred for primary aldosteronism. Blood sampling for the measurement of plasma aldosterone (PAC) and cortisol (PCC) concentration were obtained at baseline and 30 minutes after ACTH stimulation, using bilaterally simultaneous AVS. The SI was calculated as the ratio between cortisol levels in the right (C
RAV
) or left (C
LAV
) adrenal vein and the infrarenal inferior vena cava (C
IVC
); the LI was assessed as the ratio of aldosterone to cortisol on the side with the higher ratio (A/C
SIDE
) over the contralateral aldosterone to cortisol (A/C
CTRL
). The diagnosis of APA was based on pathology and follow-up data.

Results.
The HD induced a highly significant increase of PCC in IVC (+83%, P<0.003) and on the SI on both sides (SI
RIGHT
+120%; SI
LEFT
+122%, P<0.001), as compared to baseline values. By contrast, no significant change of PCC in IVC and of the SI was seen with the VLD. The ID elicited a significant increase of PCC in the infrarenal IVC (+82%, P<0.001), which was not significantly different from that seen with the HD. Likewise, the ID increased the SI (SI
RIGHT
+177%, P<0.001; SI
LEFT
+ 727%, P<0.001). In the patients with an unequivocal diagnosis or APA based on the ‘four corners’ criteria, the HD and the ID led to wrong identification of the APA side in 28 and 25%, respectively.

Conclusions.
The HD and the ID improve the ascertainment of the selectivity of adrenal vein catheterization during AVS; by contrast, no significant effect of the VLD on either PAC or PCC was seen. The improvement in the assessment of selectivity with both the HD and the ID should be weighed against the confounding effect on correct identification of lateralized aldosterone excess to the APA side.
Abstract 1072: Myocardial and Microvascular Stunning in Apical Ballooning Syndrome
Authors: De Caterina Alberto R , Porfidia Angelo , Giubilato Simona , Marzo Francesca , Pieroni Maurizio , Rebuzzi Antonio G , Crea Filippo , Galiuto Leonarda
Published: July 2021

Apical Ballooning Syndrome (ABS) is characterized by chest pain, ST segment elevation at ECG, normal coronary arteries and transient left ventricular (LV) apical a-dyskinesia that typically recovers within a few weeks. Limited and conflicting data about microvascular flow pattern in ABS exist so far. Eight consecutive patients (all women, 72±14 years) presenting with ABS were evaluated by Myocardial Contrast Echocardiography (MCE) at rest, during adenosine test and at 1 month follow-up. Myocardial dysfunction was assessed by Wall Motion Score Index (WMSI) and endocardial length of contractile dysfunction defect (CDD), while myocardial perfusion by Contrast Score Index (CSI) and endocardial length of perfusion defect (PD). MCE study was performed during the infusion of contrast medium (Sonovue, Bracco) at rest and at peak of 90 seconds-infusion of adenosine (140 μg/Kg/min) to elicit coronary microvascular response. LV perfusion defect was present in apical dysfunctional myocardium in all patients. Compared to resting condition, during adenosine WMSI decreased from 1.90±0.29 to 1.72±0.32 (p<.01) and CDD from 40.3±15.5% to 33.2±15.3% of LV endocardial length (p<.001). Similarly, during adenosine test, CSI decreased from 1.55±0.21 to 1.36±0.16, (p<.01) and PD from 23.8±8.6% to 18.6±6.5% of LV endocardial length (p<.05). At follow-up, both myocardial and microvascular dysfunction reverted to normal. Our early results indicate that ABS is characterized by a condition of regional myocardial and microvascular dysfunction partially reversible during adenosine infusion and entirely reversible at 1-month follow-up. These observations suggest that myocardial stunning associated with microvascular stunning could represent a common pathophysiologic pattern in ABS.
Abstract 1121: It’s All in the Family: A Treatable Cause of Late-Onset Hypertrophic Cardiomyopathy
Authors: Daly Ryan P , Rodriguez E. Rene , Klein Allan L
Published: July 2021

A 73-year-old woman with a history of hypertension (HTN) and mild aortic insufficiency (AI) presented to clinic with progressive dyspnea, fatigue and decreased functional capacity. Her family history was remarkable for a 45-year-old son with a “weak heart” and kidney dysfunction that was being evaluated. Her physical exam was unremarkable with the exception of bradycardia. ECG revealed sinus bradycardia of 46-bpm and a complete RBBB. Transthoracic echo revealed a small cavity with severely increased wall thickness, with obliteration in systole, with no obstruction and mild AI; notably without a history of poorly controlled HTN or significant valvular disease. A right heart catheterization revealed low output failure with a FICK cardiac index of 1.9 L/min-m2. Of note, her son’s work-up revealed Fabry’s disease, with cardiac and renal involvement. Her alpha-galactosidase enzyme levels were low-normal. A cardiac MRI with late gadolinium enhancement revealed a pattern of fibrosis suggestive infiltrative disease, and atypical for HOCM. Endocardial biopsy demonstrated myelin figures with curvilinear bodies in multiple myocytes on ultrastructural examination, diagnostic for cardiac Fabry’s disease. Enzymatic replacement therapy was initiated and a DDD pacemaker was placed with improvement of her NYHA class and BNP level. A treatable disease, representing up to 4% of late-onset hypertrophic cardiomyopathy (HCM), Fabry’s disease should be considered when evaluating patients with non-obstructive HCM. Keys to establishing this diagnosis lay in integrating clinical, genetic, and imaging data and recognizing Fabry’s disease as an X-linked dominant (not recessive) disease that may have isolated cardiac involvement, in heterozygous females, despite low-normal alpha-galactosidase activity.
Abstract 2009: ALX-0081 a Novel Anti-Thrombotic: Results of a Single-Dose Phase 1 Study in Healthy Volunteers and Further Development in Patients with Stable Angina Undergoing PCI
Authors: Bartunek Jozef , Barbato Emanuele , Holz Josefin-Beate , Vercruysse Kristof , Ulrichts Hans , Ablynx NV , Heyndrickx Guy
Published: July 2021

Background
: ALX-0081 is a bivalent Nanobody
®
based on the variable domain of naturally occurring heavy-chain only antibodies. It binds with high affinity to the A1 domain of von Willebrand Factor (vWF) and thereby blocks the interactions between platelets and vascular collagen. It selectively prevents thrombus formation under high shear stress conditions.

Aim
: Test ALX-0081 single IV infusions (60 minutes) dosed from 0.5mg to 12mg total in 40 male healthy volunteers in double-blind, randomized, placebo controlled study and assess pharmacokinetic (PK), pharmacodynamic (PD), safety and immunogenicity.

Results
: ALX-0081 displayed non-linear pharmacokinetic properties, following a 2 compartment model. Ristocetin induced platelet aggregation (RIPA) was analyzed as marker for PD effect with full inhibition (defined as measured levels dropping <10%) observed at ALX-0081 concentrations of ~ 400ng/ml. All subjects dosed ≥ 2mg achieved full RIPA inhibition at 1h post-dosing for maximum of 12h. ALX-0081 treatment was well tolerated and safe, no signs of bleeding were reported and no immunogenic response was detected. Target related mild and transient reductions of vWF and FVIII plasma levels were observed and all events were fully reversible.

Phase Ib study design
: double-blind, randomized, placebo controlled, multiple ascending dose study. ALX-0081 added to standard anti-thrombotic regimen (ASA, clopidogrel, UFH) in patients with stable angina undergoing elective PCI. Single-dose escalation will be followed by multiple dosing (up to 4 doses in 24h). Dose escalation will be guided by safety and efficacy marker.

Endpoints:
safety, pharmacological profile, biomarker (RIPA, RICO and ACT) and early clinical outcome (MACE, IMR, molecular marker).

Conclusion
: ALX-0081 can be administered safely over a wide range of dose-regimen. First results of the phase Ib study in stable angina patients will be presented.
Abstract 2043: Even Minimal Interruptions in Chest Compression for Ventilation Significantly Decreases Coronary Perfusion Pressure
Authors: Yu Tao , Ritagno Giuseppe , Cho Jun H , Sun Shijie , Weil Max H , Tang Wanchun
Published: July 2021

We have previously reported, on the basis of experimental studies, that interruptions of CPR as little as 10 seconds adversely affect the outcomes of CPR. We therefore investigated interruptions of only 5 seconds for delivering ventilation, which corresponds to the current AHA algorithm in which of 30 compressions followed by 2 ventilations are mandated. We hypothesized that even 5 seconds interruption significantly reduces CPP and with significant delay prior to restoring pre-interruption levels. Ventricular fibrillation (VF) was induced and untreated for 15 minutes in 33 male domestic pigs weighting 40±3 Kg. Chest compressions delivered with the aid of mechanical compressor (Thumper, 1000, MI Instruments) with a rate of 100/min. Ventilations were administrated with a compression / ventilation ratio of 30:2 such that 2 ventilations were delivered over a 5 seconds interval. CPP was continuously measured as the difference between comparison diastolic and simultaneous left atrial pressure. CPP significantly decreased during interruptions for ventilation from 20.5±12.8 mmHg to 9.8±6.7 mmHg(
P
<0.001). After chest compressions were restarted, the CPP increased to 12.5±7.6 mmHg after first compression(
P
<0.001). A total of 12±7 compressions over a mean interval of 7.2±4.3 seconds was required prior to restoration of CPP to levels corresponding to those that preceded the interruption. As little as the five seconds of interruption in chest compression currently mandated for 30 to 2 ventilations during CPR significantly reduced CPP and delayed restoration of CPP to its pre-interruption level.
Abstract 2055: Non-Invasive Measurements for Predicting Duration of Untreated Cardiac Arrest
Authors: Ristagno Giuseppe , Cho Jun H , Yu Tao , Li Yongqin , Sun Shijie , Weil Max H , Tang Wanchun
Published: July 2021

Objective.
Initial chest compression rather than defibrillation has evolved as the initial intervention when the duration of untreated cardiac arrest exceeds 4 min. Accordingly, we sought methods by which the duration of untreated cardiac arrest could be reliably estimated and communicated to the rescuer. Both AMSA (the amplitude spectrum area) together with measurements of tissue PCO
2
in the buccal mucosa (P
BU
CO2) were investigated. We hypothesized that decreases in AMSA, reflecting reduced myocardial electrical function, and increases in P
BU
CO
2
, reflecting the severity of anaerobic metabolism, would fulfil this need.

Materials and Methods.
In 9 domestic male pigs weighing 41 ± 2 kg, ventricular fibrillation (VF) was electrically induced and untreated for 15 min. AMSA was analyzed by fast Fourier transform from the ECG signal obtained through conventional precordial electrodes. P
BU
CO
2
was continuously measured utilizing a miniature optical sensor system (CO
2
ABG Module, Vasomed, Minneapolis, MN) applied non-invasively on to the buccal mucosa.

Results
. After 3 min of untreated VF, the AMSA value decreased significantly (p < 0.01, Figure

). P
BU
CO
2
progressively increased, exceeding threshold levels after 4 min. AMSA and P
BU
CO
2
were remarkably highly correlated with the durations of untreated cardiac arrest (r = 0.99 and r = 0.92, p < 0.0001) and with each other (r = −0.95, p < 0.0001).

Conclusion.
AMSA and P
BU
CO
2
both represent methods by which the duration of untreated cardiac arrest may be identified such as to prompt rescuer to immediately defibrillate or begin chest compression.
Abstract 2059: Transthoracic Application of Medium Voltage Therapy Maintains Forward Blood Flow during Cardiac Arrest
Authors: Ristagno Giuseppe , Li Yongqin , Wang Hao , Sun Shijie , Byron Gilman , Weil Max H , Tang Wanchun
Published: July 2021

We have previously reported that transthoracic medium voltage therapy (MVT) generated coronary perfusion pressure (CPP), forward carotid blood flow (CBF) and end-tidal CO
2
(EtCO
2
) comparable to those produced by manual chest compression. In the present study, we investigated the capability of MVT to generate and maintain forward blood flow for a longer interval, i.e. 1 min, in a porcine model of short duration cardiac arrest. MVT can maintain threshold levels of CPP, CBF and EtCO
2
, for a minute interval prior to defibrillation. In 7 domestic male pigs weighing 40 ± 1 kg, VF was electrically induced and untreated for 10 seconds. Animals were then subjected to receive MVT for one minute with the aid of a Galvani E-CPR device (Galvani Ltd, Edina, MN), after when a biphasic shock was delivered. The MVT pulsed packet was 400 msec, the pulsed packet rate was 80/min, the intra-packet pulse period was 25 ms and intra-packet pulse durations were 0.2 ms. CPP and EtCO2 were continuously measured during MVT. CBF and ejection fraction generated during MVT were measured by echo-Doppler technique, while cardiac output with stroke volume by thermodiluition method. MVT was able to maintain CPP and EtCO2 above the threshold levels for successful resuscitation for the entire interval of application (Table

). During MVT, excellent stroke volume, cardiac output and ejection fraction together with carotid blood flow were generated (Table

). MVT produced and maintained for one minute forward blood flow during cardiac arrest. This electrical therapy might represent a new approach intended to generate and/or maintain forward blood flow in lieu of or in association with chest compression in victims of cardiac arrest