bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 9276: Optimizing Cardiac Progenitor Cell-Sheet Therapy by Adding Endothelial Progenitor Cell Transplantation for Ischemic Cardiomyopathy: An Analysis of Layer-Specific Regional Cardiac Function
Authors: kamata Sokichi , Miyagawa Shigeru , Nakatani Satoshi , Fukushima Satsuki , Saito Atsuhiro , Harada Akima , Kawamoto Atsuhiko , Shimizu Tatsuya , Okano Teruo , Asahara Takayuki , Sawa Yoshiki
Published: April 2024

Background:
Transplantation of cell-sheet generated by cardiac progenitor cells (CPCs) is a promising therapeutic strategy for ischemic cardiomyopathy (ICM), while potential ischemia in the transplanted area remains to be overcome. Endothelial progenitor cells (EPCs) reportedly induce angiogenesis in the injected territory.

Hypothesis:
Concomitant EPC injection might enhance the therapeutic effects of CPC cell-sheet in ICM.

Methods:
Scaffold-free CPC cell-sheet was generated from human primary c-kit
+
heart-derived cells. ICM model was generated by placing the ameroid ring around the left coronary artery for 4 weeks in swine. They then underwent sham operation, CPC cell-sheet transplantation over the epicardial infarct area, or cell-sheet plus human EPC i.m. injection (n=5 in each), followed by the efficacy assessment for 2 months.

Results:
Speckle-tracking echocardiography dissected layer-specific regional systolic function by the radial strain. The epicardial radial strain in the infarct area was similarly greater after the CPC sole (19±5%) and the combination (20±5%) than that after the sham (7±1%,
P
=0.01). In contrast, the endocardial radial strain in the infarct area was greater after the combination (14±2%) than that after the CPC sole (11±2%,
P
=0.04) or the sham (9±1%,
P
=0.02), suggesting addition of EPC injection may enhance the functional recovery in the endocardium. Consequently, significant improvement in the left ventricular ejection fraction by the CPC sole therapy (43±5%, P=0.03) compared to the sham (32±4%) was further enhanced by the combination therapy (53±4%,
P
=0.01), assessed by the multi-detector-raw CT. Consistently, histological findings, including
in-situ
hybridization with human specific primers, revealed additional EPC injection significantly increased capillaries in the infarct area (272±38/mm
2
vs. 195±32/mm
2
vs. 85±26/mm
2
) and induced differentiation of transplanted CPCs into the myogenic and endothelial lineages.

Conclusion:
Transplantation of CPC cell-sheet induced functional recovery in the epicardial infarct area, whereas concomitant EPC transplantation achieved a transmural recovery associated with enhanced neovascularization and possible cardiomyogenic differentiation in ICM.
Abstract 9313: Contrast-Enhanced Ultrasound Imaging of Carotid Plaque Neovascularization is Useful for Identification of High-Risk Patients for Atherosclerotic Cardiovascular Diseases
Authors: Deyama Juntaro , Takishima Isao , Nakamura Takamitsu , Uematsu Manabu , Sugamata Wataru , Fujioka Daisuke , Sano Keita , Saito Yukio , Kitta Yoshinobu , Kawabata Ken-ichi , Obata Jun-ei , Kugiyama Kiyotaka
Published: April 2024

Increased neovascularization in atherosclerotic plaques represents a feature of unstable plaques. Contrast-enhanced ultrasound (CEU) could be a potential technique for imaging plaque neovascularization in the carotid artery. This study examined whether CEU of the carotid artery may provide information of risk of cardiovascular diseases.

Methods and Results:
A total of 117 patients with CAD and a carotid plaque (IMT > 1.1 mm) underwent CEU study of the carotid artery. The carotid CEU was performed using perfluorobutane microbubbles as an ultrasound contrast agent and harmonic imaging software. The intra-plaque neovascularization was identified based on the rapid movement of the echogenic reflectors of microbubbles within the plaque. The plaque neovascularization was graded: Grade (G) 0, no visible microbubbles within the plaque; G1, moderate microbubbles confined to plaque adventitial side and/or shoulder; G2, extensive microbubbles throughout the plaque. In a total of 252 plaques from the study patients, the G1 plaque neovascularization was noted in 51 plaques (20%) and G2 in 27 plaques (11%). Patients with higher grade of the plaque neovascularization had higher prevalence of smoking, older age, higher levels of LDL-C and HbA1c, higher systolic blood pressure, greater PWV and carotid IMT (p < 0.05 in all). In logistic regression analysis, the G1/G2 plaque neovascularization was associated with acute coronary syndromes, multi-vessel coronary disease, chronic total coronary occlusions, ASO and previous stroke (OR 1.5, 2.0, 1.8, 2.2 and 1.6, 95% CI 1.2-2.5, 1.5-2.8, 1.1-3.1, 1.4-3.4 and 1.2-2.9, respectively, p < 0.01 in all), that was independent of carotid IMT. The change in plaque neovascularization during 6 months was examined in a subgroup of 30 patients. Plaque neovascularization regressed in 16 ( 80%) of 20 plaques graded as G1/G2 of 16 patients taking statin, while the regression did not occur in any plaques in 14 patients taking no statin. The carotid IMT did not change in either patients with or without statin treatment.

Conclusions:
The contrast-enhanced ultrasound study of the carotid artery may provide valuable information for risk status of systemic atherosclerosis and for efficacy of anti-atherosclerotic treatment beyond carotid IMT.
Abstract 9326: Peri-Operative Myocardial Damage in Higher-Risk Patients Undergoing Elective Non-Cardiac Surgery
Authors: Alcock Richard F , Kouzios Dorothy , Hillis Graham , Brieger David
Published: April 2024

Introduction:
The development of high-sensitivity assays has greatly improved the analytical performance of cardiac troponin, allowing detection of very minor damage to cardiac muscle. High sensitivity troponin (hsTnT) is elevated in subgroups of stable populations, with prognostic significance. We postulated hsTnT would be elevated in a proportion of patients undergoing elective non-cardiac surgery, with this elevation predicting adverse peri-operative events.

Aims:
The aims of our study were to identify the incidence of elevated hsTnT in patients undergoing non-cardiac surgery, and to determine the association between elevated pre-operative hsTnT and adverse peri-operative events.

Methods:
Consecutive patients aged ≥45 years undergoing major elective non-cardiac surgery, prescribed anti-platelet therapy for primary or secondary cardiovascular event prevention, were included. Baseline, 24 and 48-hour post-operative hsTnT (Roche Diagnostics, 99th percentile 13ng/L) were collected, an elevation above the 99th percentile or if baseline hsTnT elevated, a delta value of 30%, used to define myocardial damage.

Results:
Included in the analysis were 160 consecutive patients undergoing elective non-cardiac surgery (mean age 72.3 ± 9.7 years, 66% male). Baseline hsTnT was elevated in 29.5% of all patients. Peri-operative myocardial damage occurred in 28.6% of patients. Independent predictors of peri-operative myocardial damage included age (HR 1.07, 1.02-1.12), intra-operative hypotension (HR 3.65, 1.34-9.91), and pre-operative haemoglobin (Hb) concentration (HR 0.97, 0.95-0.99). Baseline elevated hsTnT did not predict peri-operative myocardial damage. Myocardial infarction as defined by the Universal Definition occurred in only 2.7% of patients.

Conclusions:
Although pre-operative hsTnT was commonly elevated in this cohort, there was no significant association with post-operative myocardial damage. We found 28% of stable higher-risk patients undergoing elective non-cardiac surgery have hsTnT determined peri-operative myocardial damage. The significant associations of intra-operative hypotension and pre-operative Hb concentration suggest myocardial damage is predominantly due to a supply and demand mismatch.
Abstract 9346: Left Ventricular Dyssynchrony Estimated by Real time 3D Echocardiography Acutely Onset after ST-Elevation Myocardial Infarction Predicts Left Ventricular Remodeling
Authors: Iwahashi Noriaki , Kosuge Masami , Maejima Nobuhiko , Endo Mitsuaki , Tsukahara Kengo , Tahara Yoshio , Hibi Kiyoshi , Ebina Toshiaki , Sumita Shinichi , Uchino Kazuaki , Ishikawa Toshiyuki , Umemura Satoshi , Kimura Kazuo
Published: April 2024

Background:
Left ventricular dyssynchrony, estimated by speckle-tracking radial strain immediately after AMI, has been recognized as a predictor of LV remodeling.

Methods:
The study included 119 consecutive patients (99men, 64years, maxCPK=3138±3642IU/l) presenting with a first ST-elevation AMI (STEMI) who underwent primary PCI within 12 hours of onset. Within 24 h of intervention, 2D echocardiography, including tissue Doppler, speckle-tracking strains, and 3D echocardiography, was performed by iE33 and Q-lab version 8.1 (CMQ and 3DQ ADV, Philips inc). Echocardiography was repeated 12 months later and LV remodeling was defined as an absolute increase in LVEDV of at least 20%. The absolute difference (Tmsv-16dif) and standard deviation (SD) of the time to regional LV minimum systolic volume (Tmsv-16SD) for all 16 segments were assessed by 3D echocardiography. The absolute differences in time-to-peak radial (Tm-rad), circumferential (Tm-cir), and longitudinal (Tm-lon) strains were assessed for the earliest versus the latest activated segments. Longitudinal images were obtained by their apical 4-, 2-, long axis view and longitudianal strain was calculated from these images.

Results:
In total, 37 patients had LV remodeling at the 12-month follow-up. Each dyssynchronous index was a significant predictor for LV remodeling. Table shows univariate and multivariate analysis for predicting LV remodeling. Multivariable analysis demonstrated that Tmsv-16SD was the independent predictor among these indexes (Odds ratio=1.183, CI : 1.039-1.441, p=0.0046). We corrected Tmsv-16SD by the R-R interval to give Tmsv-16SD%. The Tmsv-16SD% value strongly predicted LV remodeling (Odds ratio = 1.609, CI : 1.336-2.029, p<0.0001).

Conclusions:
In patients with a first STEMI, LV dyssynchrony assessed by 3D echocardiography immediately after reperfusion therapy can predict LV remodeling within 12 months.
Abstract 9361: Role of 3 D Speckle Tracking Echocardiography to Detect Left Ventricular Dysfunction. Initial Experience in a Routine Clinical Laboratory
Authors: Saha Samir , Kiotsekoglou Anatoli , Toole Rena , Gopal Aasha S
Published: April 2024

Background:
Left ventricular (LV) volumes and strain obtained by 3D speckle tracking echocardiography requires investigation to assess the relative discriminatory power of one over the other that has not been studied in a clinical laboratory, thereby justifying the rationale of this study.

Methods:
38 human subjects with normal echocardiogram and 88 subjects (58 ±14 years, 53 M) with abnormal echocardiogram (structural and/or coronary artery disease) underwent 3 D speckle tracking echocardiography (3D-STE) using a custom SW (Tomtec). The data obtained were end- systolic and diastolic volumes (ESV, EDV), LVEF, 3D strain, 3D circumferential strain (CS %) and 3D radial strain (RS %). Objective of the study was to assess the comparative diagnostic power of the 3D STE data to identify diseased LV.

Results:
ROC analyses yielded areas under the curve (AUC) values for ESV (0.85), LVEF (0.84),3D strain ( 0.81), 3D RS%( 0.79), 3D CS%( 0.76), and EDV ( 0.76). Pairwise comparison of the AUC showed that ESV had a significantly greater AUC than EDV (p<0.0001),and global CS% (p<0.05). LVEEF was however superior to GCS% ( p<0.01). 3D strain differed from global CS% (p<0.05) as well. 3D- LVEF could be predicted from linear regression equation using both 3D global strain (y = 6.8376 + -1.2022 x, R2= 0.78, P<0.0001) as well as by 3 D circumferential strain (y = 16.2762 + -1.3113 x, R2 = 0.78, P<0.0001).

Conclusions:
The association of LVEF with the strain indicates the validity of 3 D strain as a possible surrogate for LVEF with a fairly acceptable regression value. The data also suggest that 3D STE is a robust technique and that the volumetric parameters (ESV, LVEF) appear to be more powerful to discriminate normal from abnormal LV compared with 3D-STE strain obtained from multiple myocardial vectors.
Abstract 9368: Plasma Membrane Calcium ATPase Isoform 1 Protects the Heart from Cardiomyopathy, Arrhythmias and Hypertension
Authors: Shaheen Mohamed A , Mohamed Tamer M , Prehar Sukhpal , Zi Min , Stafford Nicholas P , Roberts Samantha , Garnett Hannah , Wang Yanwen , Lei Ming , Austin Clare E , Neyses Ludwig , Cartwright Elizabeth J
Published: April 2024

With 1 in 3 people in the USA dying as a result of cardiovascular disease, and the incidence of these diseases rapidly increasing in the developing world, it is essential that we continue to provide mechanistic insights into their development and progression. Several recent human genome wide association studies have identified single nucleotide polymorphisms in the plasma membrane calcium ATPase isoform 1 (PMCA1) gene as the strongest association with hypertension and blood pressure variance; hypertension along with cardiomyopathy and arrhythmias are central features of heart failure. In this study we provide evidence that PMCA1, which is a transmembrane calcium transporter known to eject calcium from the cell, is involved in all of these key features of heart failure. To elucidate the role of PMCA1 in cardiac function we generated mice carrying a cardiomyocyte-specific gene deletion of PMCA1 (PMCA1
cko
). In response to pressure overload hypertrophic stress induced by transverse aortic constriction (TAC) PMCA1
cko
mice displayed accelerated cardiac dysfunction shown by significantly reduced fractional shortening compared to controls (FS; PMCA1
cko
/TAC: 21±2%, PMCA1
f/f
/TAC 32±3%, PMCA1
cko
/Sham and [alpha]-MHC-Cre/TAC 35±2%,
p
<0.05, n=6). This was accompanied by increased lung weight/body weight in PMCA1
cko
/TAC (11.5±1
vs
7.8±0.8 mg/g in PMCA1
f/f
/TAC,
p
<0.05, n=6), greater cardiomyocyte cross-sectional area and significantly elevated interstitial fibrosis. Our data shows that in the myocardium PMCA1 has an additional role in stabilising cardiac rhythm. At 3 months of age PMCA1
cko
displayed episodes of spontaneous ventricular tachycardia whilst exhibiting an 80% downregulation in the expression of the voltage gated sodium channel Na
v
1.5 and a significant reduction in the corresponding current. To investigate the relationship between PMCA1 and blood pressure we generated PMCA1 heterozygous knockout mice (PMCA1
Ht
) in which both systolic and diastolic carotid pressure was significantly increased in PMCA1
Ht
in comparison to wild type littermates. In conclusion, this data addresses the mechanistic basis for the association of PMCA1 with hypertension, cardiomyopathy and arrhythmias which are key contributors to heart failure.
Abstract 9396: A Genetic Fate-Mapping Study Showing That Leukemia Inhibitory Factor Stimulates Cardiac Stem Cell-Derived Cardiomyocyte Renewal After Myocardial Infarction
Authors: Kanda Masato , Nagai Toshio , Takahashi Toshinao , Liu Mei Lan , Tokunaga Masakuni , Naito Atsuhiko , Akazawa Hiroshi , Kobayashi Yoshio , Komuro Issei
Published: April 2024

Introduction:
Recent studies have contradicted the notion that the adult heart is a terminally differentiated organ. The source of cardiac regeneration and its relation with cardio-protective drugs remain controversial. Using a genetic fate-mapping model, we examined the rate of stem cell-derived cardiomyocyte renewal, focusing on the effect of leukemia inhibitory factor (LIF) on cardiac stem cells.

Methods and Results:
We generated MerCreMer-LacZ mice, in which more than 99.9% of the cardiomyocytes in the left ventricular field showed positive 5-bromo-4-chloro-3-indolyl-β-D-galactoside (Xgal) staining just after tamoxifen injection. Thus, every Xgal-negative cardiomyocyte was derived from a stem or precursor cell after tamoxifen administration. During normal aging spanning 1 year, the number of Xgal-negative cardiomyocytes in the mice did not change significantly: 2 weeks, 9.8 ± 3.8 cells per section; 1 year, 9.8 ± 5.2 cells per section. In contrast, at 6 months after myocardial infarction (MI), the MI mice had more Xgal-negative cells (41.0 ± 9.3 cells per section) than the control mice (8.0 ± 2.6 cells per section; P < 0.001) did. We injected the LIF plasmid or phosphate-buffered saline (PBS) at the time of MI. At 1 month after MI, the MI + LIF group (118.6 ± 51.5 cells per section) had a greater number of Xgal-negative cells than the MI + PBS group (37.0 ± 5.5 cells per section; P < 0.05) did. Echocardiography showed significant recovery of functional shortening in the LIF-treated group only. To detect the source of LIF-induced cardiomyocyte renewal, we studied cardiac side population (SP) cells. SP cells were found to have LIF receptors, and the percentage of phosphorylated signal transducers and activators of transcription 3-positive and cyclin D1-positive SP cells increased after LIF stimulation in vitro. In addition, continuous 5-bromodeoxyuridine (BrdU) administration during the first week after MI resulted in 68.9% BrdU-positive SP cells in LIF-treated mice, but only 30.5% in PBS-treated mice, suggesting that LIF influenced SP cell proliferation.

Conclusion:
LIF may stimulate stem cell-derived cardiomyocyte regeneration in part by activating SP cells. Our findings should help provide a novel strategy for therapeutic cardiogenesis.
Abstract 9426: Is Aspirin Beneficial for Primary Prevention of Cardiovascular Events in High-Risk Diabetic Patients? -Insights from the JPAD Trial
Authors: Okada Sadanori , Morimoto Takeshi , Ogawa Hisao , Sakuma Mio , Soejima Hirofumi , Nakayama Masafumi , Doi Naofumi , Kubo Atsushi , Akai Yasuhiro , Kawano Takahiro , Jinnouchi Hideaki , Waki Masako , Sugiyama Seigo , Uemura Shiro , Saito Yoshihiko ,   the JPAD Traial Investigators
Published: April 2024

Benefit of low-dose aspirin for primary prevention of cardiovascular events remains controversial in diabetic patients. Recently, the ADA, AHA and ACCF jointly recommended that low-dose aspirin use is reasonable for high-risk diabetic patients: older patients with additional cardiovascular risk factors. Thus, we evaluated aspirin's benefit in diabetic patients stratified by cardiovascular risk factors in the JPAD trial. This study is a subanalysis of the JPAD trial: a randomized, controlled trial to assess whether low-dose aspirin reduced cardiovascular events in patients with type 2 diabetes and no history of cardiovascular disease. We randomly assigned 2,539 patients to the aspirin group (81 or 100 mg daily) or the no aspirin group, and followed for 4.4 years. We classified all participants into four subgroups according to the following risk stratification: age (men, >50 or ≤50 years; women, >60 or ≤60 years) and one or more additional risk factors (smoking, hypertension, dyslipidemia, family history of coronary artery disease, and proteinuria). Most of the participants were older patients with risk factors (group A: n = 1,804); however, aspirin did not reduce cardiovascular events in the group A (hazard ratio [HR]: 0.83, 95% confidence interval [CI]: 0.58 to 1.17). On the other hand, in older patients without risk factors (group B: n = 268), aspirin significantly reduced cardiovascular events (HR: 0.24, 95% CI: 0.04 to 0.89). Either in younger patients with risk factors (group C: n = 402) or without risk factors (group D: n = 58), we could not detect aspirin's benefit (group C, HR: 0.93, 95% CI: 0.27 to 2.9; group D, HR: 1.26, 95% CI: 0.05 to 32). In the present study, low-dose aspirin was beneficial for primary prevention not in older diabetic patients with additional risk factors but in those without additional risk factors. Further investigations should be needed to confirm whether low-dose aspirin is beneficial for primary prevention in diabetic patients at high risk.
Abstract 9481: Whole Body Periodic Acceleration, Novel Passive Exercise Devices, Enhances Blood Supply to Ischemic Hindlimb in Mice and Human
Authors: Rokutanda Taku , Izumiya Yasuhiro , Miura Mitsutoshi , Fukuda Shota , Shimada Kenei , Izumi Yasukatsu , Nakamura Yasuhiro , Araki Satoshi , Hanatani Shinsuke , Kim-Mitsuyama Shokei , Yoshiyama Minoru , Ogawa Hisao
Published: April 2024

Introduction:
Whole body periodic acceleration (WBPA) is a non-invasive, passive exercise device that has been shown to improve endothelial function by increasing shear stress by head-to-foot direction movements of the body. However, the impact of WBPA on blood flow to ischemic legs has not been investigated.

Hypothesis:
WBPA enhances blood supply in a mouse model of hindlimb ischemia and in patients with peripheral arterial disease (PAD).

Methods and Results:
After unilateral femoral artery excision, wild type mice were assigned to either the WBPA (n=15) or control (n=13) group. WBPA was applied at 150 cpm for 45 min under anesthesia once a day. WBPA significantly increased blood flow recovery at 7 and 14 days after surgery as determined by laser doppler perfusion imaging. Sections of ischemic adductor muscle stained with anti-CD31 antibody showed a significant increase in capillary density in WBPA-treated mice compared with control mice, suggesting that WBPA promotes angiogenesis at a microcirculatory level. WBPA increased the phosphorylation of endothelial nitric oxide synthase (eNOS) in adductor muscle. The pro-angiogenic effect of WBPA on ischemic limb was blunted in eNOS-deficient mice, suggesting that the stimulatory effects of WBPA on revascularization are eNOS-dependent. Quantitative real-time PCR analysis showed significant increases in molecules involved in angiogenesis, such as VEGF, FGF2, SDF-1, PDGF-B in ischemic hindlimb by WBPA. Protein array analysis showed that WBPA induced changes in the expression profile of serum angiogenesis-related proteins. Facilitated blood flow recovery was observed in a mouse model of diabetes despite no changes in glycemic control. Clinically, 10 patients (age, 69±7 years, 9 men) with PAD underwent single session of WBPA treatment at 140 cpm for 45 min. WBPA significantly improved the ischemic/non-ischemic ratio of blood flow in the lower extremity from 0.74±0.21 to 0.87±0.21 (p<0.05).

Conclusions:
WBPA increased blood supply to ischemic lower extremities through activation of eNOS signaling and upregulation of pro-angiogenic growth factor in ischemic skeletal muscle. WBPA is a potentially suitable non-invasive intervention to facilitate therapeutic angiogenesis.
Abstract 9551: Relative Contributions of Genetic Variants in PON
1, CYP2C19 And ABCB1 o
n in-hospital and One Year Clinical Outcomes in Patients Treated with Clopidogrel After an Acute Myocardial Infarction
Authors: Simon Tabassome , Steg Philippe Gabriel , becquemont Laurent , Verstuyft Celine , Kotti Salma , Schiele François , Ferrari Emile , Drouet Elodie , Grollier Gilles , Danchin Nicolas
Published: April 2024

Background:
Clopidogrel with aspirin reduces ischemic events in patients with acute myocardial infarction (AMI). Clopidogrel requires drug transport via P-glycoprotein, encoded by
ABCB1
, and bioactivation by CYP450, mainly via
CYP2C19
. The clinical response to clopidogrel is variable, depending in part on
CYP2C19
and
ABCB1
genetic polymorphisms. Recently however, paraoxonase-1 (PON1) was suggested as the crucial enzyme for clopidogrel bioactivation, with its Q192R polymorphism determining
per se
clopidogrel response on cardiovascular events.

Methods
We assessed the effect of
PON1
(Q192R) polymorphisms by itself and alongside variants in
CYP2C19
loss-of-function and
ABCB1
on in-hospital and one-year cardiovascular events in clopidogrel-treated AMI patients participating in the Fast-MI study (n=2208), including the subset undergoing PCI (n=1538).

Results :
PON1
(Q192R) polymorphism was not associated with increased risk of in-hospital death and one year major adverse events: One-year adjusted hazard ratio [HR] for QQ versus RR individuals, 1.03; 95% CI, 0.66-1.61 in the whole population and HR, 0.77; 95% CI, 0.42-1.41 in PCI-treated patients. Adding
ABCB1
and
CYP2C19
polymorphisms had no impact on these risks. Presence of two
CYP2C19
loss-of-function alleles was associated with the risk of in-hospital death and major clinical events at one year in the overall population (OR: 3.67; 95% CI, 1.05-12.80, and HR: 1.96, 95% CI, 1.08-3.54) and in PCI patients (OR, 6.87; 95% CI, 2.52-18.72, and HR: 3.06, 95% CI, 1.47-6.41).
ABCB1
polymorphisms had an impact on the clinical response to clopidogrel in the overall population but not in PCI patients.

Conclusion :
PON1 polymorphism was not associated with an increased risk of events in clopidogrel-treated patients with AMI and those undergoing PCI. In contrast, CYP2C19 loss- -of-function polymorphism remained the major pharmacogenetic contributor of clinical response to clopidogrel in these populations.
Abstract 9561: Connexin43 Interacts with Voltage-Gated Sodium Channel 1.5 in the Perinexus
Authors: Rhett J. M , Palatinus Joseph A , Jourdan Jane A , Gourdie Robert G
Published: April 2024

Rapid depolarization of the myocyte sarcolemma during the cardiac action potential (AP) is dependent on the voltage-gated sodium channel Na
v
1.5. Gap junctions (GJs) are thought responsible for propagation of AP between myocardial cells. Connexin43 (Cx43) is the primary isoform of GJ subunit in the working ventricular myocardium, where it localizes at intercalated disks. Previous reports from our lab have shown that the interaction of Zonula Occludens-1 (ZO-1) with Cx43 regulates the size of GJ plaques. We have further demonstrated that this interaction regulates GJ size by governing the transition of functioning connexon hemichannels into GJ intercellular channels. Moreover, we have recently determined in epithelial cells that Cx43/ZO-1 interaction extends from the GJ to a region of nonjunctional membrane proximal to the plaque called the perinexus. Here, we examine the hypotheses that cardiac GJs are also surrounded by a perinexus and that this domain contains both connexons and other channels involved in AP generation and propagation. Using the Duolink in situ protein-protein interaction assay it is confirmed that cardiomyocytes also display perinexal Cx43/ZO-1 interactions. It is also demonstrated by analysis of connexin-connexin interaction in situ that the cardiac perinexus exhibits a high density of connexon hemichannels composed of Cx43. In a further novel result, we find that the perinexus contains Na
v
1.5 complexed with Cx43, but not ZO-1. Additionally, preliminary data indicates that CT-1, an inhibitor of Cx43/ZO-1 binding, increases interaction between Na
v
1.5 and Cx43 in the perinexus. Taken together, our data confirm that cardiomyocyte GJs exhibit a perinexus. The localization of Nav1.5 in the perinexus suggests that this ephapse-like domain of close sarcolemmal apposition between myocytes has assignments in AP propagation independent of the canonical electrotonic pathway.
Abstract 9586: Existence of Small Juvenile Cells in the Aging Bone Marrow Stromal Cells and Their Therapeutic Potential for Ischemic Heart Disease
Authors: Okada Motoi , Haider Husnain K , Igura Koichi , Kim Seojin , Jiang Shujia , Ashraf Muhammad
Published: April 2024

Background:
We have previously reported that aging of stem cells compromises their growth and proliferation potential and their regenerative capacity post transplantation in the infarcted heart. We have identified small juvenile population of stem cells in aging rat derived bone marrow (BM) which expressed cardiac lineage markers GATA-4 and MEF-2C. We proposed that these cells possessed great potential for repair of the ischemic heart.

Methods and Results:
Small cells were isolated from male young (
Yng
Small; 8-12 weeks) and old (
Old
Small; 24-28 months) Fischer-344 rats BM-stromal cells by filtration through 3 μ m pore sized sieve. The proliferation and colony formation capacity of
Yng
Small cells and
Old
Small cells were significantly higher than total population of the old cells (
Old
Hetero). Flow cytometry showed both
Old
Small and
Yng
Small cells were positive for CD29, CD44, CD59 (Sca-1 homologue) and CD90 but negative for CD45 and CD117 (c-kit). Myocardial regenerative capacity of
Old
Small and
Old
Hetero cells was assessed in a rat model of acute myocardial infarction (n=10 /group) using DMEM injected animals as controls. Echocardiography at 4 weeks after cell transplantation showed preserved indices of global heart function including left ventricle (LV) diastolic volume (
Old
Hetero: 58.2±3.6 vs
Old
Small: 40.1±5.4ml,
p
<0.01), LV ejection fraction (
Old
Hetero: 48.2±5.1 vs
Old
Small: 55.2±3.8%,
p
<0.05) and fractional shortening (
Old
Hetero: 19.8±3.5 vs
Old
Small: 23.5±2.1%,
p
<0.05) in
Old
Small cell treated animals. Histological studies showed smaller infarction size in
Old
Small cell treated hearts (
Old
Hetero: 53.5±3.1 vs
Old
Small: 41.0±2.9,
p
<0.01). Border zone capillary density was higher in
Old
Small group (
Old
Hetero: 29.0±9.5 vs
Old
Small: 39.5±10.2%,
p
<0.05). We also confirmed that the QDot labeled
Old
Small cells differentiated into cardiac and endothelial cells as indentified by actinin and vWF-VIII specific immunostaining.

Conclusions:
Old
Small cell transplantation enhanced angiogenesis in border zone of infarcted heart and improved LV function as compared to
Old
Hetero. These findings suggested that
Old
Small cells could be excellent source for autologous cell transplantation in elderly patients for better prognosis.
Abstract 9589: Conduction Abnormalities in Pediatric Patients with Restrictive Cardiomyopathy
Authors: Walsh Mark A , Jefferies John L , Towbin Jeffrey A , Czosek Richard J
Published: April 2024

Introduction:
Pediatric restrictive cardiomyopathy (RCM) carries a poor prognosis secondary to a high risk of sudden cardiac death. Sudden death in pediatric patients has previously been attributed to ventricular tachyarrhythmias. There are many reasons why patients with RCM might develop conduction system disease and it is conceivable that in the acute setting, this might be a triggering event for sudden death.

Methods:
A single center, retrospective chort of pediatric patients with RCM, diagnosed between April 1994 and April 2011 was analyzed for conduction system abnormalities and potential triggering events for sudden death. Patient demographic, cardiac and electrocardiographic characteristics were reviewed. Incidence of sudden cardiac events was determined (defined as death or an episode of acute hemodynamic compromise felt to be secondary to a cardiac arrhythmia). Non-parametric statistical methods were used to determine associations between clinical characteristics and sudden cardiac events.

Results:
Fifteen patients (1 - 17 years) were reviewed; there were 5 sudden cardiac events including 4 deaths. Two of the deaths were precipitated by the abrupt onset of complete heart block. Another patient with syncope had intermittent heart block and survived as a result of the defibrillator pacing features. Sudden cardiac events were statistically associated with an older age (

p
<0.01

). On initial presentation, the median PR interval (222 vs. 140 msec;

p
< 0.01

) and the median QRS duration (111 vs. 73.5;

p
= 0.01

) was significantly longer in those having an acute cardiac event. No other functional or echocardiographic variables were associated with a sudden cardiac event.

Conclusion:
Pediatric patients with RCM are at risk for acute high grade heart block and bradycardic events may represent a significant portion of all arrhythmic events. Since PR interval prolongation and wider QRS complex were associated with acute cardiac events, these findings suggest increased monitoring for bradyarrhythmic episodes with consideration for prophylactic pacemaker implantation in certain patients. Particular care should be taken in patients with RCM and evidence of conduction system disease.
Abstract 9628: Krüppel-like Factor-10 Serves as a T cell Anti-Aging Factor in Organ Transplantation
Authors: Shimizu Koichi , Libby Peter , Folco Eduardo , Mitchell Richard , Feinberg Mark
Published: April 2024

The response of T cells to mitogens wanes with normal aging. Previous work has implicated cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) in the hyporesponsiveness of T cells in the elderly; such reduced activation could impact allograft survival. Conversely, Krüppel-like factor 10 (KLF10) is a transcription factor involved in T-cell activation. This study investigated whether KLF10 participates in age-related diminution in cardiac allograft rejection, using KLF10-deficient mice (KLF10-/-).

Methods and Results:
Major histocompatibility complex class II (MHC II)-mismatched cardiac allografts showed similar survival when transplanted into young recipients (8-12 week old) of either wild-type (WT) or KLF10-/- strains. In contrast, allografts in older KLF10-/- recipients (20-24 week old) survived an average of only 4.4±2.1 weeks (n=8), compared to >12 weeks (n = 6, p<0.0001) in older WT hosts. At 4 weeks post-transplantation, allografts in older KLF10-/- recipients had significantly higher parenchymal rejection scores (3±0.8, n=6) than did older WT recipients (1.4±0.5, n=7, p <0.005); allografts in older KLF10-/- hosts also had significantly increased allograft accumulation of T cells and macrophages, and significantly increased mRNA levels of IL-6, IFN-γ, TNF-α, MCP-1, IP-10, Mig, and I-TAC compared to WT recipient allografts. Mixed lymphocyte reactions using older KLF10-/- responder cells showed significantly higher reactions compared to WT responders (20-fold), while younger WT and KLF10-/- responders were comparable. WT T cells in older animals expressed significantly higher CTLA-4 levels (4-fold) than did those in young mice, while old KLF10-/- mice expressed lower CTLA-4 levels and higher levels of CD28 expression compared to young KLF10-/- mice. Cardiac allografts of KLF10-/- young host adoptively receiving older KLF10-/- T cells significantly augmented parenchymal rejection with increased inflammatory cell infiltration compared to young KLF10-/- T cell transferred recipient allografts.

Conclusion:
The absence of KLF10 in older recipient T cells markedly increased effector T-cell activation and exacerbated allograft rejection. Thus, KLF10 regulates age-dependent immune responses in cardiac transplantation.
Abstract 9723: Calcium Loading Induces a PKC Isoform Switch That Activates Constitutive Acetylcholine Regulated Potassium Current in Atrial Fibrillation-Related Remodeling
Authors: Makary Samy , Maguy Ange , Voigt Niels , Dobrev Dobromir , Nattel Stanley
Published: April 2024

Background:
AF causes atrial tachycardia remodeling (ATR), with enhanced constitutive acetylcholine regulated K
+
current (I
KAChc
) contributing to ATR-induced APD shortening and AF promotion. The present study examined the mechanisms underlying I
KAChc
activation; based on preliminary evidence for an essential role of phosphorylation, we evaluated the participation of protein kinase C (PKC).

Methods:
Cultured dog atrial cardiomyocytes
in vitro
tachypaced (TP) at 3 Hz for 24 hours were compared to parallel 1 Hz paced cells and cells from ATR dogs (paced
in vivo
at 400 bpm x 1 week). I
KAChc
single channel activity was assessed in cell attached and cell free (I-O) patches. Protein expression was assessed by Western blot.

Results:
In vitro
TP for 24 hours activated I
KAChc
(Fig A), mimicking effects of
in vivo
ATR. The classical PKC isoform PKCα inhibited, whereas the novel isoform PKCε enhanced, I
KAChc
when applied to the intracellular side of I-O patches. TP and ATR downregulated PKCα (by 33, 37% respectively) and caused membrane translocation of PKCε, switching PKC-predominance to the stimulatory novel isoform. TP increased [Ca
2+
]
i
at 2 hours by 30% (Fig B), with subsequent return to baseline at 24 hrs. Ca
2+
activates calpain, which breaks down proteins. Decreasing calpain activity during TP with PD150606 (20 µM) prevented TP enhancement of I
KAChc
(Fig C). Decreasing [Ca
2+
]
i
during TP with BAPTA-AM (1 µM), a cell permeable Ca
2+
chelator, also prevented TP-enhancement of I
KAChc
(Fig D). Both PD150606 and BAPTA-AM prevented downregulation of PKCα protein expression by TP. Exposure of TP cells to a PKCε inhibitor (Fig E) suppressed TP-induced I
KAChc
activation, whereas a PKCα inhibitor (Fig F) enhanced I
KAChc
activity in 1 Hz cells.

Conclusions:
Rate-related [Ca
2+
]
i
loading due to ATR causes a PKC isoform switch, with downregulation of inhibitory PKCα and membrane translocation (activation) of stimulatory PKCε, which enhances I
KAChc
causing APD shortening and AF promotion.
Abstract 9766: Impact of Duration on The Results of a Lifestyle Modification Program for The Metabolic Syndrome
Authors: Walden Patrick , Krishnan Sangeetha , Fink Samantha , Mollo Lynette , Vorndran Carla , Weintraub Martha , Oral Elif A , Rubenfire Melvyn
Published: April 2024

Background:
We have demonstrated that the staff and facilities of cardiac rehab can be used to treat the metabolic syndrome (MetSyn) in a patient-pay ($350) 3 month life-style intervention program [the Metabolic Fitness Program (MetFit)].

Objective:
To determine the relative effectiveness of extending the 3 month MetFit program to 6 months.

Methods:
All patients were physician referred and had 3 or more criteria of the MetSyn. Anthropomorphic, physiologic, and biochemical studies were obtained at baseline, 3 and 6 months. The program costs the patient $700 and consists of weekly 45 minute sessions of nutrition, exercise, and behavior education and 45 minutes of exercise supplemented by daily free use of the fitness center.

Results:
Of the 72 patients enrolled in the 6 month program, 44.4% were male and mean age was 52.1±9.5 years. Over 90% were obese and 40% were morbidly obese. Based on AHA Guidelines for the MetSyn, 72.2% were hypertensive, 87.5% had impaired fasting glucose, 98.6% had abdominal obesity, 65.3% had elevated fasting triglycerides, and 61.1% had low HDL-C. In this interim analysis, 68 (94%) had completed 3 months, 55 (76%) had completed 6 months and 8 (10%) dropped out of the program. The change in parameters associated with the MetSyn at 3 and 6 months are shown in Table 1. Forty-seven % of patients lost at least one criteria of MetSyn after 6 months of the program compared to 28% at 3 months (p=0.027). At 6 months, 27% no longer had the MetSyn compared to 13% at 3 months (p<.0001).

Conclusions:
This interim analysis of the MetFit program targeting the metabolic syndrome suggests that patients will obtain more benefit after 6 months compared to 3 months. Drop-out rate was not affected with the longer program despite the higher cost to the patient. The long term benefits of programs like MetFit remain to be seen.
Abstract 9782: Genetic Variation at the
SLCO1B1
Gene Locus and Low Density Lipoprotein Cholesterol Lowering Response to Pravastatin in the Elderly
Authors: Akao Hironobu , Polisecki Eliana , Kajinami Kouji , Trompet Stella , Jukema J Wouter , de Craen Anton J , Westendorp Rudi G , Shepherd James , Packard Christopher , Buckley Brendan M , Schaefer Ernst J
Published: April 2024

Background:
Statins have been shown to significantly lower the risk of coronary heart disease morbidity and mortality, and these benefits have been related t lowering of low density lipoprotein (LDL) cholesterol lowering. Statin metabolism is affected by the liver X receptor alpha (
LXRA
) and the solute carrier organic anion transporter (
SLCO1B1
). The
SLCO1B1
rs4149056 variant has been linked to an increased risk of statin induced myositis due to decreased liver uptake of the statin, increased blood levels, and presumably greater statin uptake in muscle tissue. Our goal was to determine whether genetic variation at these gene loci would influence low density lipoprotein (LDL) cholesterol lowering with pravastatin, baseline heart disease, or cardiac endpoints on trial.

Methods:
We examined associations of single nucleotide polymorphisms (SNPs) at the
LXRA
(rs12221497) and
SLCO1B1
(rs4149056 and rs2306283) gene loci with these variables in 5411 participants in PROSPER (Prospective Study of Pravastatin in the Elderly at Risk) (mean age 75.3 years), who had been randomized to pravastatin 40 mg/day or placebo and were followed for a mean of 3.2 years.

Results:
No relationships between genetic variation at the
LXRA
gene locus with statin induced LDL lowering response or other parameters were noted. Both the
SLCO1B1
rs4149056 (valine for alanine at 174) and the rs2306283 (asparagine for aspartic acid at 130) SNPs affect the amino acid of the
SLCO1B1
gene product. No effects of the rs2306283 SNP on any of the variables was noted. However the presence of the rs4149056 SNP was associated with significantly less LDL cholesterol lowering response to pravastatin (wildtype, 71.5% of the population, -37.0%, heterozygotes, 25.8% of the population, -36.0%, and homozygotes, 2.7% of the population, -31.8%, p=0.003.

Conclusions:
Our data indicate that the presence of the rs4149056 non-synonymous SNP at the
SLCO1B1
gene locus, especially in the approximately 3% of the population that are homozygous for this variant, can significantly decrease the pravastatin induced LDL cholesterol lowering response. Therefore the presence of this variant not only predicts statin induced myositis, but also statin induced LDL lowering response.
Abstract 9815: Cardioprotective Effect Of Neuregulin-1 In Myocardial Ischemia-Reperfusion Injury Relies On eNos.
Authors: Lemmens Katrien , Hervent Anne-Sophie , Demolder Marc , De Keulenaer Gilles
Published: April 2024

Background:
The neuregulin-1 (NRG1)/erbB system is an endothelium-controlled paracrine system, which protects the heart during myocardial stress. Subcellular mechanisms of this protection have not been identified. We previously observed that NRG1 activates cardiomyocyte endothelial nitric oxide synthase (eNOS), leading to desensitization of the myocardium for beta-1-adrenergic inotropic effects. In this study, we tested whether eNOS also participates during NRG1-mediated protection against myocardial ischemia-reperfusion (I/R) injury.

Methods:
C57BL/6 (wild type, WT) and eNOS knockout (KO) mice were pre-treated with rNRG1 (20μ g/kg/d, ip) or vehicle for 3 days. Next, they were subjected to 30 min of ischemia by coronary artery ligation, followed by 4h reperfusion. Sham operated littermates served as control. Investigators were blinded for pre-treatment of mice.

Results:
Left ventricular (LV) NRG1 expression, erbB2 and erbB4 receptor activity remained unaffected by I/R injury (30min/4h) or by genetic background. rNRG1 significantly increased LV erbB2 and erbB4 phosphorylation in WT and KO mice. I/R injury blunted eNOS phosphorylation in WT mice (-57±15%, p<0,05), which was completely prevented by rNRG1. In WT mice, rNRG1 reduced infarct area by 9±2% as compared to vehicle. In contrast, rNRG1 had no effect on infarct area in eNOS KO mice (= 7/group, p =0.001 for NRG1 treatment, p=0.02 for interaction). Also, in WT but not in eNOS KO mice, rNRG1 increased fractional shortening by 11±4% (p<0.05). Interestingly, rNRG1 reduced polymorphonuclear cell influx into infarct and border zones in WT (157±17 cells/mm
2
in vehicle versus 78±18 cells/mm
2
in NRG1 treated WT mice) but had no effect on polymorphonuclear influx in eNOS KO (144±15 cells/mm
2
in vehicle versus 126±10 cells/mm
2
in NRG1 treated KO mice, p=0.008 for NRG1 treatment, p=0.07 for interaction).

Conclusions:
An activated NRG1/erbB system prevents blunting of myocardial eNOS phosphorylation during I/R, and attenuates myocardial I/R injury. These events are causally related as indicated by the loss of rNRG1-induced protection in eNOS KO mice.
Abstract 9920: Growth Differentiation Factor 15, ST2 and Natriuretic Peptides in Heart Failure with Preserved versus Reduced Ejection Fraction
Authors: Santhanakrishnan Rajalakshmi , Chong Jenny P , Richards Arthur M , Lam Carolyn S
Published: April 2024

Background:
Growth differentiation factor 15 (GDF15) is part of the TGF-β superfamily and a marker of cell injury and inflammation. ST2 is part of the interleukin-1 receptor family and a marker of mechanical stress and ventricular remodeling. While each of these novel markers is elevated in heart failure (HF), little is known regarding their differential levels in HF with preserved vs reduced ejection fraction (HFPEF vs HFREF respectively) or relative to the established marker of wall stretch, amino terminal pro B type natriuretic peptide (NTproBNP).

Aim:
To compare circulating GDF15, ST2, NTproBNP and their ratios in HFPEF vs HFREF

Hypotheses:
Since GDF15, ST2 and NTproBNP are markers of distinct mechanistic processes that may be differentially involved in HFPEF vs HFREF, we hypothesized that a combination of markers may better distinguish between HFPEF and HFREF than a single marker.

Methods and Results:
GDF15, ST2 and NTproBNP were measured in consecutive patients hospitalized with HFREF (N=20, 58±5 y, 85% men) and HFPEF (EF≥50%, N=12, 68±11 y, 58% men). Despite similarly raised filling pressures (E/e’ 20±11 in HFREF vs 19±9 in HFPEF; p=0.8), NTproBNP was lower in HFPEF than HFREF, whereas GDF15 and ST2 were similar raised in both HFPEF and HFREF (Table). The ratio GDF15:NTproBNP was higher in HFPEF than HFREF, even after adjusting for age, sex and body size (p=0.025), and distinguished HFPEF from HFREF with the largest area under receiver operating curve. Among the biomarkers, only NTproBNP correlated with left ventricular mass (r=0.44; p=0.012).

Conclusions:
This pilot study suggests that at similarly high filling pressures, myocardial injury/ inflammation (as measured by GDF15) relative to wall stretch (GDF:NTproBNP ratio) is dominant in HFPEF compared to HFREF. Future studies in larger samples of HF patients and including non-HF controls are needed to further delineate the relationships of these novel biomarkers with ventricular remodeling.
Abstract 9939: Insulin Receptor Substrate-2 Genetic Variants Interact with Plasma Monounsaturated and n-3 PUFA Fatty Acid Levels to Influence Insulin Resistance: From the LIPGENE Study
Authors: Perez-Martinez Pablo , Delgado-Lista Javier , Garcia-Rios Antonio , Gulseth Hanne L , Blaak Ellen E , Kieć-Wilk Beata , Helal Olfa , Lovegrove Julie A , Riserus Ulf , Roche Helen M , Lopez-Miranda Jose
Published: April 2024

Background:
The insulin receptor substrate-2 (IRS-2) is a major insulin signalling molecule. IRS-2 regulates body weight control and glucose homeostasis. Several
IRS-2
polymorphic sites have been studied for their potential use as risk markers for obesity and type 2 diabetes mellitus. Fatty acids are key metabolic regulators which may interact with genetic factors and influence glucose metabolism.

Objective:
To examine whether the genetic variability at the
IRS-2
gene locus was associated with the degree of insulin resistance and plasma fatty acid levels in subjects with metabolic syndrome (MetS).

Design:
Intravenous glucose tolerance tests (IVGTT) and HOMA indices were used to estimate insulin sensitivity (insulin sensitivity index, HOMA-IR), insulin secretion (first phase insulin secretion (AIRg), disposition index, HOMA-B) and glucose effectiveness. Plasma fatty acid composition and three
IRS-2
single nucleotide polymorphisms (SNPs) were also determined in a cross-sectional analysis of 452 subjects with MetS participating in the LIPGENE dietary intervention cohort (
NCT00429195
).

Results:
The rs2289046 SNP interacted with plasma monounsaturated (MUFA) and omega-3 polyunsaturated fatty acids (n-3 PUFA) levels which were significantly associated with insulin resistance. Among subjects with the lowest level of MUFA (below the median) the A/A genotype was associated with lower glucose effectiveness (P<0.03), higher fasting insulin concentrations (P<0.02) and higher HOMA-IR (P<0.03) compared to subjects carrying the minor G-allele (A/G and G/G). In contrast, among subjects with the highest level of MUFA (above the median), the A/A genotype was associated with lower fasting insulin concentrations and HOMA-IR. Whereas, individuals carrying the G allele and with the highest level of n-3 PUFA (above the median) showed lower fasting insulin (P<0.01) and HOMA-IR (P<0.02) compared with A/A subjects.

Conclusions:
The rs2289046 polymorphism at the
IRS-2
gene locus may influence insulin resistance and glucose effectiveness by interacting with plasma fatty acid composition in subjects with the MetS. Further studies are needed to confirm whether targeted dietary recommendations can prevent MetS in genetically susceptible individuals.