bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 17060: Incidence of Tissue Coring during Transseptal Catheterization When Using Electrocautery and a Standard Transseptal Needle
Authors: Greenstein Eugene , Knight Bradley P , Lin Albert C , Passman Rod
Published: April 2024

Introduction.
The application of radiofrequency (RF) electrocautery to a standard, open-ended transseptal needle has been used to facilitate transseptal puncture (TSP). The purpose of this study was to determine the incidence of cardiac tissue coring when this technique is used.

Methods.
A model using excised swine hearts submerged in a saline-filled basin was developed to simulate TSP with electrocautery and a standard transseptal needle. Four types of adult Brockenbrough needles and two different size swine hearts were used. Punctures were performed without the use of electrocautery, and by delivering RF energy to the transseptal needle using a standard Bovie electrocautery pen and an RF generator set to 10W and 15W, in both “pure” and “blend” cut settings, at three target sites (Fossa Ovalis [FO], non-Fossa Ovalis septum [Non-FO], and Aortic [AO]). The tissue of the submerged heart was gently tented, and the needle was advanced on delivery of RF. The devices were retracted, and the needle was flushed in a collection basin. The basin was inspected for tissue.

Results.
See Figure. None of the TSPs without cautery caused tissue coring. For TSP's using electrocautery, the frequency of coring was at least 21% for any puncture permutation used in the study, and averaged 37% at septal sites (p < 0.05 compared to punctures without cautery). Tissue coring occurred in 33/96 (35%) punctures through the FO, and 38/96 (40%) punctures through non-FO septum (Figure 3a). The frequency of tissue coring at aortic sites was 62/96 (65%), which was significantly higher than at the septal sites (p<0.001).

Conclusions.
In an animal preparation, TSP at the level of the fossa ovalis using electrocautery and a standard open-ended Brockenbrough needle resulted in coring of the septal tissue in one third of cases. These results raise concern about the risk of systemic embolism of cardiac tissue when this technique is used in humans.
Abstract 17073: Avoiding Shocks by Programming a High Number of Antitachycardia Pacing Attempts for Fast Ventricular Tachycardia: A Prospective Study
Authors: Martins Raphaël P , Blangy Hugues , Muresan Lucian , Freysz Luc , Groben Laurent , Zinzius Pierre-Yves , Scwartz Jérôme , Sellal Jean-Marc , Aliot Etienne , Sadoul Nicolas
Published: April 2024

Purpose:
Antitachycardia pacing (ATP) is a painless therapy reducing defibrillation shocks in implantable cardioverter-defibrillator (ICD) recipients. One or 2 ATP attempts are usually programmed to terminate fast ventricular tachycardia (FVT) episodes and avoid shocks without delaying successful treatment in case of ATP failure. Programming more ATP attempts could probably reduce the occurrence of shocks.

Objective:
We sought to analyze the long-term efficacy and safety of programming a high number of ATP attempts for FVT.

Methods:
All patients receiving a first ICD in our center for coronary artery disease (CAD) and dilated cardiomyopathy in primary and secondary prevention indications between 2000 and 2009 were prospectively included in the study. ICDs were programmed to deliver 10 ATP attempts for FVT cycle lengths (CL) of 250 to 300 ms (200 to 240 bpm) before high energy shock delivery (5 bursts, then 5 ramps; 8 to 10 extrastimuli at 81 to 88% of the FVT CL; minimal pacing CL 180 ms).

Results:
We prospectively included 770 patients (men 84%; CAD 75.5%; age 63.2 ± 11 years; secondary indication 54.3%; left ventricular ejection fraction 30.3±9%), followed for 40.6 ± 25.6 months. Among them, 137 patients (17.8%) had a total of 1839 episodes of FVT (mean frequency 209 ± 9.2 bpm). ATP terminated 1713 episodes of FVT (unadjusted efficacy, 93.1%; GEE adjusted 81.7%) and acceleration occurred in 5.8% of episodes. A large majority of episodes were successfully treated (98.3%) by 1 or 2 ATP sequences. Conversely, the patient-based analysis showed that 17 (12.4%), 8 (5.8%) and 5 patients (2.1%) had one episode or more treated by at least 3, 4 or 5 ATP attempts, respectively. These patients would have been shocked with a conventional ICD programming. The benefit of this strategy was reduced for 6 to 10 attempts and only 10 patients were shocks for ATP failure (20 episodes, 1.1%). Despite the high number of attempts programmed, FVT episodes were mainly asymptomatic and found during device interrogation: syncope and pre-syncope occurred in 0.2% and 0.4% of episodes, respectively.

Conclusions:
Programming a high number of ATP attempts (at least 4 or 5 ATP sequences) in the FVT zone is both safe and useful. It could prevent painful shocks for FVT in a high proportion of ICD recipients.
Abstract 17119: Renal Sympathetic Denervation Using an “Off-the-Shelf” Irrigated Radiofrequency Ablation Catheter for the Management of Drug-Resistant Hypertension
Authors: Ahmed Humera , Neuzil Petr , Skoda Honza , Petru Honza , Sediva Lucie , Schejbalova Marcela , Reddy Vivek Y
Published: April 2024

Introduction:
Catheter-based renal sympathetic denervation using a specialized radiofrequency (RF) ablation catheter has recently been demonstrated to achieve sustained BP lowering in drug-refractory hypertension (HTN) pts. In theory, this non-irrigated RF ablation catheter has the potential to cause char formation at the point of catheter-tissue contact. We studied whether the same saline-irrigated RF ablation catheters used for ablation at other cardiovascular sites, which in theory would minimize the thromboembolic risk related to ablation itself, can safely provide similar BP reduction in refractory HTN pts.

Methods:
Ten pts with drug-resistant HTN (7±1 anti-hypertensive drugs/pt) underwent bilateral renal denervation with a standard saline-irrigated RF ablation catheter. Ambulatory BP recordings (24-hr) were obtained at baseline, and 1, 3, and 6 months post-procedure. In 5 pts, pre- and post-procedural measures of renal sympathetic activity were assessed, including plasma aldosterone, metanephrine, normetanephrine and plasma renin activity. All pts underwent follow-up renal angiography (at 1-5 months) to assess for renal artery (RA) stenosis.

Results:
Over a 6 month period, 1) the mean change in systolic/diastolic BP was -28/-20 mmHg; 2) all patients experienced a decrease in systolic BP of at least 10 mm Hg (range: 10-32 mm Hg); 3) there was no evidence of RA stenosis or aneurysm at repeat angiography; and 4) there was a significant decrease in renal sympathetic activity at 3 months: including metanephrine (-12±4, p=0.003) and normetanephrine (-17±4, p=0.0008) levels. There was also a significant decrease in aldosterone levels (-60±33 ng/l, p=0.02). Changes in the remaining variables were not significant: plasma renin activity (0.2 mg/l/hod, p=0.4), serum creatinine (-1 mmol/L, p=0.4); renin (0.3 mg/l/hod, p=0.4).

Conclusions:
Renal sympathetic denervation can be performed safely and effectively in pts with resistant hypertension using a standard saline-irrigated ablation catheter. Randomized placebo-controlled trials remain necessary to rule out a biofeedback-mediated placebo effect.
Abstract 17135: Serum 25-Hydroxyvitamin D Deficiency Increases Risk of Myocardial Infarction: Results From the Prospective Monica/Kora Augsburg Case-Cohort Study
Authors: Karakas Mahir , Thorand Barbara , Zierer Astrid , Huth Cornelia , Meisinger Christa , Roden Michael , Rottbauer Wolfgang , Peters Annette , Koenig Wolfgang , Herder Christian
Published: April 2024

Background:
A growing body of evidence suggests that vitamin D deficiency may adversely affect the cardiovascular system, but data from longitudinal studies are lacking. Circulating 25-hydroxyvitamin D3 (25[OH]D), the most commonly used index of vitamin D status, is converted to the active hormone 1,25-dihydroxyvitamin D3 (1,25[OH]2D), which, operating through the vitamin D receptor, inhibits in vitro cell proliferation, induces differentiation and apoptosis, and may protect against coronary heart disease (CHD). Therefore, the aim was to prospectively assess the association between serum (25[OH]D) concentrations and incident CHD.

Methods:
Using a case-cohort design, serum levels of (25[OH]D) were measured in 1,783 subjects (964 men, 819 women) selected from a source population of 9,300 middle-aged participants in the population-based MONICA/KORA Augsburg studies.

Results:
A total of 298 CHD cases (225 male, 73 female) were identified over an 11-year average follow-up period. We found a significant interaction of the effects of vitamin D with sex. After adjustment for age, survey, and season of blood sampling, the hazard ratio (HR) and 95% confidence interval (CI) comparing tertile extremes of serum levels of (25[OH]D) was 0.32 (0.16-0.65) (p for trend=0.001) in women, and 0.56 (0.38-0.82) (p-trend=0.005) in men. Further adjustment for standard cardiovascular risk factors (including BMI, smoking, physical activity, alcohol, systolic blood pressure, total cholesterol/HDL-cholesterol ratio, and parental history) slightly attenuated the association in women (HR: 0.39 [0.18-0.84] p-trend=0.013, and strongly in men (HR: 0.76 [0.49-1.17] p-trend=0.215). After additional adjustment for C-reactive protein, interleukin-6, ICAM-1, and IP-10, the effect remained significant in women (HR: 0.42 [0.19-0.93] p-trend=0.028) while it was further reduced in men (HR: 0.84 [0.52-1.35] p-trend=0.461).

Conclusions:
Our findings suggest that higher vitamin D status is associated with decreased risk of CHD. This effect seems to be particularly pronounced in women. Further clinical and experimental studies are needed to investigate the sex differences and whether or not correction of vitamin D deficiency could contribute to the prevention of CHD.
Abstract 17143: RASSF5, a New Mediator of Angiogenesis, Mediates Integrin Endocytosis in Endothelial Cells and Vessel Stability in vivo
Authors: Manavski Yosif , Carmona Guillaume , Del Galdo Sabrina , Wieland Thomas , Dimmeler Stefanie , Kroll Jens , Chavakis Emmanouil
Published: April 2024

Integrins are critical mediators of angiogenesis. In our previous work, we identified the GTPase Rap1 as a mediator of integrin activation in endothelial cells (EC) and angiogenesis. RASSF5/RAPL is an effector protein of Rap1 promoting integrin activation and adhesion in lymphocytes. However, the role of RASSF5 for integrin regulation in EC and angiogenesis is unclear. Silencing of RASSF5 with siRNA significantly decreased angiogenic sprouting of HUVEC in a 3-dimensional spheroidal system (83 % inhibition) and blocked VEGF-induced invasion (68 % inhibition), while not inhibiting EC proliferation. Surprisingly, while silencing of Rap1 reduced HUVEC adhesion, silencing of RASSF5 unexpectedly significantly increased integrin-dependent adhesion suggesting distinct roles for RASSF5 and Rap1 in integrin regulation in EC. In line with these results, silencing of RASSF5 significantly increased surface expression of beta1-integrin as assessed by FACS, while not affecting total beta1-integrin protein levels in HUVEC. It is conceivable, that the enhanced surface expression of beta1-integrins upon silencing of RASSF5 is caused by a redistribution of the integrin from an intracellular pool to the cell surface. Therefore, we studied the role of RASSF5 for the endocytosis of beta1-integrins in HUVEC. Strikingly, silencing of RASSF5 blocked beta1-integrin endocytosis by 43 ± 6 %. Interestingly, silencing of RASSF5 preferentially reduced the internalization of activated (matrix-bound) alpha5beta1-integrins. Endogenous alpha5-integrin co-immunoprecipitated with overexpressed RASSF5. In addition, silencing of RASSF5 enhanced actin polymerization and Rac1 activity in EC. Strikingly, in vivo silencing of the RASSF5 homologue in the zebrafish embryo with morpholino led to hemorrhages in the newly formed vessels. In conclusion, our results demonstrate that RASSF5 is binding to the alpha5beta1-integrin and mediating integrin internalization and actin cytoskeleton reorganization in EC, thereby promoting angiogenic sprouting and migration. Our data identify a new angiogenic signaling pathway and shed light on the relevance of alpha5beta1-integrin endocytosis for angiogenic functions such as sprouting, migration and vessel stability.
Abstract 17172: Adiponectin Promoter Elements Combined with Liver-Specific microRNA-122 Target Sequences Specifically Target Adipose Tissue for Gene Transfer with Intravenous Delivery an AAV8 Vector
Authors: O'Neill Sean M , Hinkle Christine C , Chen Shu-Jen , Sandhu Arbans K , Johnston Julie , Reilly Muredach P
Published: April 2024

Objective:
To develop an
in vivo
, systemic method of gene transfer specifically targeting adipose tissue. We assessed the hypothesis that systemic adeno-associated virus (AAV)-mediated vector delivery can transfer genes specifically to adipose tissue.

Background:
Obesity is a major risk factor for developing coronary heart disease. Adipose is an endocrine organ critical to energy intake and expenditure. Available data on adipose is limited, in part, because of the difficulties in adapting experimental techniques to a tissue with high lipid content. Few studies have investigated
in vivo
gene transfer in adipose tissue, and these studies used subcutaneous injections in obese mice.

Method and Results:
Tail vein IV injections of a luciferase expression vector in healthy C57BL/6 mice revealed that AAV serotype 8 (AAV8) best targeted adipose tissue. Tail vein injections of AAV8 were used to administer all subsequent vectors in five mice per vector. Mice were sacrificed 2-3 weeks after injection, and tissues were analyzed for transgene expression. Systemic delivery of a vector containing the GFP gene under control of a CMV promoter induced GFP transgene expression in most tissues tested, including subcutaneous, omental, gonadal, and brown fat depots. To restrict GFP expression to adipose depots, the CMV promoter was replaced with an adiponectin enhancer/promoter to make Adipo-GFP AAV. Systemic delivery of Adipo-GFP AAV induced GFP expression in all adipose depots tested. GFP expression in non-adipose tissues was negligible except for liver. To ameliorate unwanted liver expression, target sites for liver specific microRNA -122 were incorporated into the vector to make Adipo-GFP-miR122 AAV. Mice injected with Adipo-GFP-miR122 AAV no longer expressed GFP in liver, yet they expressed GFP in adipose tissue. Furthermore, mature adipocytes isolated from adipose tissue express GFP, indicating Adipo-GFP-miR122 vector targets mature adipocytes for transgene expression.

Conclusion:
AAV8-mediated systemic delivery of a specifically designed adipose expression vector can selectively target adipose tissue for
in vivo
gene transfer. This novel approach has therapeutic potential in obesity and downstream complications like insulin resistance and diabetes.
Abstract 17186: Genetic Deletion of Circadian Clock Gene Reduces the Extent of Myocardial Ischemia-Reperfusion Injury
Authors: Bhushan Shashi , Predmore Benjamin L , Lavu Madhav , Rudic R D , Lefer David J
Published: April 2024

Background:
The importance of circadian clock is well known in cardiovascular health and disease. Circadian clocks are transcriptionally based molecular mechanisms that regulate cellular function during the course of the day. Previous studies have demonstrated that circadian clock genes contribute to daily changes in heart rate and blood pressure. In the present study we investigated the effects of genetic deficiency of the Clock gene on the severity of myocardial ischemia-reperfuson (MI-R) injury.

Methods:
Wild-type (WT) and Clock knockout (KO) mice (24-27 weeks) were utilized for the study. 2-D echocardiography was performed at baseline to assess heart rate (HR) and left ventricular (LV) function for both Clock KO and WT mice. Mice (n=9-13) were subjected to 45 min of myocardial ischemia (MI) induced by left coronary artery occlusion and 24 hrs of R in vivo. LV area-at-risk (AAR) and infarct (INF) size were determined with Evan's blue dye and 2,3,5-triphenyl tetrazolium chloride (TTC) staining.

Results:
We failed to observe any differences in HR between the WT (491±18 BPM) and Clock KO (471±15 BPM) mice (p=NS). In addition, LV ejection fraction was similar in WT (63 ± 2%) and Clock KO (63 ± 2%) mice (p=NS). However, we did observe a significant reduction in myocardial infarct size with respect to area-at-risk of Clock KO mice compared to (WT) mice (25.5 ± 3% vs. 41.8± 6%, respectively, p < 0.01).

Conclusions:
While additional studies are required to define the precise cellular and molecular signals that are influenced by the circadian clock at the time of MI-R injury, these studies suggest that Clock does exert a significant influence in the onset of pathology during myocardial infarction.
Abstract 172: Cumulative SAPS II Score Fails to Predict Mortality in Out-of-Hospital Cardiac Arrest
Authors: Salciccioli Justin D , Dejam Andre , Giberson Tyler , Melillo Tara , Cocchi Michael N , Donnino Michael W
Published: April 2024

Introduction:
Severity of illness scores can predict outcomes in critically ill patients. However, the calibration of existing scoring systems in post-cardiac arrest patients is poorly established.

Objective:
To determine if the Simplified Acute Physiology Score (SAPS II) will predict mortality in out-of-hospital cardiac arrest (OHCA).

Methods:
An observational study of adult cardiac arrest at an urban tertiary care hospital during the period from 12/2007 to 12/2010. Data were collected prospectively and recorded in the Utstein style. Inclusion criteria: 1. Adult (>18 years); 2. OHCA; 3. Return of spontaneous circulation. Traumatic cardiac arrests were excluded. Patient demographics, co-morbid conditions, vital signs and laboratory data and in-hospital mortality were recorded. SAPS II scores were calculated. We used simple descriptive statistics to describe the study population and logistic regression to predict mortality with SAPS II as the predictor variable. Forward stepwise logistic regression selection was used to identify individual SAPS II variables that contribute to the sensitivity of the score. Discrimination was assessed using area under the curve (AUC) of the receiver operating characteristic (ROC) curve.

Results:
115 patients were analyzed. The median age was 68 years (IQR: 55 - 79) and 28% were female. Median SAPS II score was 67 (IQR: 53 - 77) and 61% of patients died. Cumulative SAPS II score was a poor predictor of mortality (p = 0.19, OR: 1.012, 95% CI: 0.99 - 1.03) and demonstrated poor discrimination (AUC: 0.61). Stepwise selection identified the following individual SAPS II variables to predict mortality: HC03 (p = 0.006, OR: 1.46, 95%CI: 1.12 - 1.90), GCS (p = 0.03, OR: 1.12, 95%CI: 1.01 - 1.23), and age (p = 0.02, OR: 1.12, 95%CI: 1.02 - 1.23); together these are strong predictors of mortality: p = 0.02, AUC: 0.75.

Conclusion:
Cumulative SAPS II scoring fails to predict mortality in OHCA. The risk-score assigned to age, GCS and HC03 independently predict mortality and combined are good mortality predictors. These findings suggest that an alternative severity of illness score should be used in post-cardiac arrest patients. Future studies should determine optimal risk-scores of SAPS II variables in a larger cohort of OHCA.
Abstract 17209: Diabetes Mellitus Potentially Can Cause Diastolic Dysfunction
Authors: Sturdy Megan , Jeong Euy-Myoung , Dudley Samuel C
Published: April 2024

Introduction:
Diastolic dysfunction (DD) is observed in about 40% of patients with diabetes mellitus (DM). DM is associated with DD in epidemiological trails. Previously, cardiac oxidation and fibrosis have been associated with DD in animal models. We sought to determine whether these mechanisms occurred in the DM type 2 KK.CgAy mouse model. Furthermore, we sought to determine if advanced glycosylation end products (AGE), oxidative stress, and fibrosis may be involved in causing DD.

Methods:
Echocardiography and single cell measures of cardiomyocytes were used to determine if wild type (C57/BL6J) and KK.CgAy mice had DD. Western blotting against dinitorphenylhydrozone derivatizatives detected oxidized protein levels (Oxyblot) and immunohistochemistry was performed to determine collagen levels. Sarcomere function of contraction and relaxation were assessed by IonOptix System under stimulation at 1.0Hz, 4ms duration at 37’C perfusion.

Results:
The DM type 2 KK.CgAy mouse model shows DD by echocardiography. The ratio of E ‘/A’ is significantly lower in KK.CgAy compared to C57 control mice (0.73 ± 0.17 vs. control 1.08 ± 0.28, P<0.05). There was no difference in AGE, TGF-β, or collagen levels when comparing control group to KK.CgAy mice. Oxidatively modified proteins under 50 KDa were significantly increased in KK.CgAy mice (3.44 ± 0.09 fold, P<0.01). Indicative of DD, resting sarcomere length was shorter in KK.CgAy mice (1.65 ± 0.01 μ m vs. control 1.83 ± 0.01 μ m, P<0.001). The isolated myocyte relaxation constant, tau, was significantly increased in KK.CgAy mice (0.13 ± 0.01 μ m vs. control 0.08 ± 0.01, P<0.01) indicating relaxation impairment of diasolic dysfunction in DM model.

Conclusion:
Our study indicates that DM can cause DD and that the molecular mechanism is associated with oxidative modification of proteins. Fibrosis and advanced glycosylation end products were not associated with DD in the DM type 2 KK.CgAy mouse model.
Abstract 17226: Vascular Smooth Muscle Responsiveness to a Nitric Oxide Donor is Impaired in Healthy Adults with Increased Adiposity
Authors: Christou Demetra D , Pierce Gary L , Seals Douglas R
Published: April 2024

Background-
Vascular smooth muscle responsiveness to an exogenous nitric oxide donor (i.e., nitroglycerin-induced dilation; NID) is impaired in cardiovascular disease and in adults at risk for atherosclerosis. Although adiposity is associated with increased risk of atherosclerosis, its relation to NID is poorly defined. We sought to examine the relation of NID to total and abdominal adiposity in a healthy group of men and women varying widely in adiposity levels and age.

Methods and Results-
In 224 carefully screened adults (age:18-79 yrs, body mass index (BMI): 16.4-42.2 kg/m
2
), we measured NID, total body adiposity (BMI and % body fat (%BF); dual-energy x-ray absorptiometry) and indices of abdominal adiposity (waist circumference (WC) and waist to hip ratio (WHR)). In a subgroup of 74 subjects, we also measured total abdominal (TAF), abdominal visceral (AVF) and subcutaneous fat (ASF) using CT scans. NID was determined as the vasodilator response (brachial ultrasonography) to 0.4 mg sublingual nitroglycerin. Based on multiple linear regression analyses, NID was negatively related to BMI (part correlation coefficient (r
part
)=-0.19, P=0.004) and not related with total %BF (r
part
=-0.12, P=0.07), whereas it was consistently negatively related with abdominal adiposity (WC, r
part
=-0.22; WHR, r
part
=-0.19; TAF, r
part
=-0.36; AVF, r
part
=-0.36; and ASF, r
part
=-0.30, all P≤0.009), independent of sex. Accounting for systolic blood pressure, high density lipoprotein (HDL) cholesterol and fasting blood glucose reduced all of the sex-independent relations between NID and adiposity by 3 to 42%, but overall the relations remained significant (P≤0.05). NID was 35% lower in a subgroup of subjects with the highest compared to the lowest quintile of abdominal visceral fat (P=0.003). This difference in NID was abolished after accounting for systolic blood pressure (P=0.2) and HDL cholesterol (P=0.1) but was not changed after accounting for fasting glucose (P=0.002).

Conclusions-
Total adiposity is modestly (BMI) or not related (% body fat) with NID, whereas abdominal adiposity is more consistently and strongly related with NID. Adiposity may influence NID in part via modulation of blood pressure, HDL cholesterol and/or fasting glucose.
Abstract 17244: Monocytes and Oxidized Lipids Promote the Destabilization of Calcified Plaque Via Matrix Metalloproteinases(MMP)
Authors: Li Rongsong , Mittelstein David , Majumdar Rohit , Lee Juhyun , Tintut Yin , Demer Linda , Hsiai Tzung
Published: April 2024

Objective:
Vascular calcification is closely associated with atherosclerosis, but whether it mechanically affects plaque stability remains controversial. We previously showed that calcific nodules produced with cultured calcifying vascular cells (CVC) were destabilized in response to shear stress. Here, we characterized the CVC-derived calcified nodules in ApoE-null mice, and assessed oxLDL and monocytes on the destabilization of CVC-derived calcified nodules under pulsatile shear stress (PSS).

Methods and Results:
To demonstrate that CVC-derived calcified nodules contain components of calcific atherosclerotic plaque in vivo, CVC was implanted in the ApoE-null mice via a cage. After 6 weeks, histology and immunohistochemsitry revealed a calcified plaque-like structure with fibrous caps, lipids, Collagen II, alkaline phosphotase and friable shoulders. To investigate the calcific nodule destabilization
in vitro
, CVC nodules were subjected to PSS for two and one-half hours. The percentage of nodules detached was calculated as quantification of nodule destabilization. Computational Fluid Dynamic (CFD) code simulated the instantaneous shear force distribution on the individual nodules and demonstrated accentuated instantaneous shear forces on the shoulder regions of nodules. Treatment with oxLDL or co-culture with monocytic THP-1 cells promoted the destabilization of nodules(Nodules detached: control (PSS) = 24±3%, PSS + THP-1=57±6%, PSS + oxLDL=45±7%, n=4,
P
<0.001). Both oxLDL and THP-1 significantly up-regulated the expression of MMP-1, MMP-3 and MMP-9 in CVC, and increased the activities of MMP. MMP inhibitor, GM6001, significantly reversed oxLDL- and THP-1-induced nodule destabilization, whereas over-expression of MMP9 increased nodule destabilization.

Conclusion:
These findings revealed that calcific CVC nodules resembled atherosclerotic plaque
in vivo
, and active lipids and monocytes induced CVC nodules to express MMP, promoting destabilization of the calcified nodules. This study provides a dynamic model to characterize the destabilization of calcific atherosclerotic plaque
in vitro
.
Abstract 17268: Resolution of Aortic Regurgitation following Fetal Balloon Aortic Valvuloplasty
Authors: Pluchinotta Francesca R , Marshall Audrey C , McElhinney Doff B , Wilkins-Haug Louise E , Benson Carol B , Sanders Stephen P , Lock James E , Tworetzky Wayne
Published: April 2024

Background.
Fetal balloon aortic valvuloplasty (FAV) can improve left heart growth and function, preventing evolution to HLHS in some patients. Aortic regurgitation (AR) is frequently observed by color Doppler after technically successful FAV. In contrast to neonatal valvuloplasty, fetal AR has been observed to improve and even resolve by birth. Our aim is to analyze anatomic and technical factors that might result in AR post FAV and characterize the resolution of AR in the perinatal period.

Methods.
Fetuses who underwent a technically successful FAV were reviewed and the following variables analyzed: aortic valve diameter; balloon to annulus ratio (BAR); and gestational age (GA) at FAV.

Results.
Sixty-five fetuses had a technically successful FAV at a median GA of 23 (19-31) weeks. AR was observed immediately after the FAV in 40 fetuses (62%); trivial or mild in 19 and moderate or severe in 21 fetuses. The BAR was larger in fetuses that developed significant AR (1.20±0.13 versus 1.06±0.14;
P
=0.003). Two of 16 fetuses (13%) with a BAR ≤1 developed significant AR compared to 39% of fetuses with a BAR >1. Three of 21 fetuses with significant AR died after the procedure. The AR resolved completely in 9 of 18 survivors (50%), improved to trivial or mild in 7 (39%), and remained severe until birth in 2 (11%). Both patients with persistent severe AR died as newborns.

Conclusions.
FAV carries a risk of AR. However, in most fetuses the AR improves by late gestation. A larger BAR (>1) is a risk factor for significant AR. The mechanism of AR resolution might be wound healing factors unique to the fetus. These include rapid cell division and the ability to repair and remodel tissue as demonstrated in animal studies. Moreover, unique hemodynamic factors such as reduced diastolic afterload due to the placenta and elevated LV end-diastolic pressure could mitigate the degree of AR, allowing for valve remodelling.
Abstract 17275: Induction of Arteriogenesis in Mouse Hindlimb by Human Peripheral Blood B Cells as Determined by Micro-CT Imaging
Authors: Goodchild Traci , Sweet Michael , Yue Jianing , Godwin Lisa , Chronos Nicolas , Poznansky Mark , Singh Jai Pal
Published: April 2024

For patients with critical limb ischemia, restoration of blood flow through mechanical or pharmacological revascularization is an important therapeutic goal. Clinical studies have been unsuccessful in enhancement of neovascularization by treatment with angiogenic growth factors. We have shown that bone marrow derived B cells delivered into rat ischemic myocardium preserves cardiac function (Goodchild et al, 2009) and we sought to determine if B cells could be therapeutically beneficial in a mouse model of critical limb ischemia. Since commonly used histological determination of angiogenesis only provides semi-quantitative measure of vessels in limited tissue area without confirming perfusion functionality, this study measured the angiogenic and arteriogenic activities of B cell therapy using high resolution computed tomography. Mice (n=16, Balb/c) had iliac and femoral arteries and veins ligated. Mouse bone marrow B cells (CD19+) isolated by antibody-magnetic bead selection or saline control was injected directly into ischemic muscles. A post-ligation laser Doppler scan was performed to ensure ligation consistency then scanned weekly. On Day 28, mice were euthanized, vasculature flushed, fixed and perfused with contrast agent. Limbs were imaged by micro-CT with reconstruction at 25um. Data represented as vascular segment number and area counted in 500 slices in 3D micro-CT images. At Days 7, 14, 21 and 28, blood flow increased in B cell treated ischemic hindlimbs compared to controls. At Day 28, B cell treatment increased number of vessels in treated-ligated legs compared to unligated legs (8033±439 vs. 5297±710 vessels, respectively; P=0.010) and vessel area (175.9±45.4 vs. 99.0±28.6 mm2, respectively; P=0.012). Vessels ranging from 25-175 and 225-350um were increased in B cell treated-ligated legs compared to unligated legs (P<0.05). Vessel number ratio in treated-ligated legs to unligated legs was higher in B cell treated compared to control treated mice (1.66 vs. 1.05; P=0.025). These data show that unlike angiogenic response to treatment with growth factors, B cells enhanced development of vessels with a wide range of diameters suggesting that B cells may offer therapeutic potential for treatment of ischemic peripheral artery disease.
Abstract 17316: Inhibition of Calcineurin/NFAT Signaling During Exercise Training Protects the Heart Against Myocardial-Ischemia Reperfusion Injury
Authors: Moody Bridgette , Hood Rebecca L , Nicholson Chad K , Lefer David J , Calvert John W
Published: April 2024

Background:
Exercise training confers sustainable protection against ischemia-reperfusion injury in animal models and has been associated with improved survival following a heart attack in humans. It is still unclear how exercise protects the heart, but there is evidence to suggest that during heart failure exercise training can reduce the cardiac activity of nuclear factor of activated T-cells (NFAT), a transcription factor associated with pathological hypertrophy and cell death. However, the mechanism(s) responsible for this inhibition is not fully understood and it is not known if the inhibition of NFAT is associated with the preconditioning effects of exercise. Therefore, we investigated if exercise could precondition the heart by inhibiting NFAT.

Methods and Results:
Mice (C57BL/6J) that engaged in voluntary exercise for 4 wks (VE 4 wks) revealed an 18% reduction in infarct size per area-at-risk (INF/AAR) following 45 min of myocardial ischemia and 24 hr of reperfusion when compared to sedentary (SED) mice (49 vs. 60%, p<0.05) and a 37% reduction in circulating troponin-I levels when compared to SED mice (45 vs. 28 ng/mL, p<0.05). In separate experiments, SED and VE mice were sacrificed immediately after the training period and heart tissue was excised and processed for Western blot analysis. We found that VE decreased the nuclear expression of both NFATc2 and NFATc4 in the hearts of the trained mice when compared to the SED mice. Further analysis revealed that VE did not alter the expression of the calcium-calmodulin-activated protein phosphatase calcineurin-Aβ (CnAβ), but did increase the expression of the calcineurin inhibiting sarcomeric protein calsarcin-1 and increased the association of calsarcin-1 and CnAβ.

Conclusions:
This data suggests that exercise training potentially protects the heart against MI/R upregulating the expression of calsarcin-1, which leads to an inhibition of Cn/NFAT signaling.
Abstract 17320: Signaling Mechanisms Involved In Beta3-adrenergic Receptor Regulation of Nnos in Isolated Cardiomyocytes
Authors: Watts Vabren L , Niu Xiaolin , Miller Karen L , Barouch Lili A
Published: April 2024

Beta3 -adrenergic (beta3-AR) receptors play a pivotal role in modulating cardiac function, though their precise role in the heart remains controversial. We have recently demonstrated that beta3-mediated cardiac protection via negative inotropy is lost in nNOS-/- animals under pressure overload as compared with WT. However, the exact manner in which beta3-AR activation regulates nNOS signaling to stimulate NOS activity at the cardiomyocyte level is unknown. In this study we used a specific beta3-AR agonist,
BRL37344
(BRL), to assess the role of beta3-AR in nNOS regulation in hypertrophied isolated neonatal rat ventricular cardiomyocytes (NRVM). To induce hypertrophy we pretreated cells with norepinephrine for 72 hours, which resulted in a 70% increase in cell size and a 25% increase in beta3-AR mRNA expression as compared with non-hypertrophied cells, analyzed by immunocytochemistry and real-time PCR. In hypertrophied cardiomyocytes, BRL administration lead to a time-dependent 5-fold increase in NOS activity, which was significantly suppressed by nNOS specific inhibitor LVNIO. NOS activity was measured by the arginine-to-citrulline conversion assay. BRL also cause a time-dependent 1.5-fold increase in nNOS phosphorylation at positive regulatory site Ser1416, dephosphorylation of negative regulatory site Ser847, and decreased superoxide generation as compared with unstimulated control. In addition BRL induced phosphorylation eNOS-Ser114, which indicates eNOS deactivation. Pretreatment with pertussis toxin (PTX) suppressed BRL-induced nNOS-Ser1416 phosphorylation, nNOS-Ser847 dephosphorylation, and NOS activity, and unaltered superoxide generation, suggesting Gi/o dependency. Taken together, our data suggest that BRL regulates NOS signaling in ventricular cardiomyocytes via phosphorylation regulation of nNOS. To our knowledge this is first study to demonstrate a role for nNOS phosphorylation as a key factor in beta3-AR signaling. These results contribute significantly to our understanding the negative inotropic properties of myocardial beta3-AR at cellular levels during cardiac sympathetic overstimulation, and will ultimately aid in drug discoveries that target the molecular mechanisms associated heart failure.
Abstract 17353: Effectiveness and Safety of Digoxin in Adults with Incident Systolic Heart Failure
Authors: Freeman James V , Yang Jingrong , Hlatky Mark A , Go Alan S
Published: April 2024

Background:
Current clinical guidelines endorse digoxin use for patients with symptomatic systolic heart failure (HF) on optimal medical therapy, but this recommendation is based on limited, older clinical trial data. We sought to evaluate the effectiveness and safety of digoxin in a contemporary cohort of patients with incident systolic heart failure and stratified by patient sex and serum digoxin concentration (SDC).

Methods:
We identified patients with incident systolic HF between 2006 and 2008 in the Kaiser Permanente of Northern California health system. We used multivariable extended Cox regression to examine the association between incident digoxin use and death and hospitalization for HF, controlling for patient medical history, physical exam, diagnostic tests, laboratories, and medications. Longitudinal drug use, patient characteristics and outcomes were identified based on validated algorithms using health plan automated databases. Analyses were also conducted stratifying by sex and SDC.

Results:
Among 2891 patients with incident systolic HF followed for a mean 2.4 years, digoxin users had higher rates of death (14.2% vs 11.3%) and HF hospitalization (28.2% vs 24.4%). In adjusted analysis, digoxin was associated with excess mortality (odds ratio (OR) 1.60, 95% confidence interval (CI) 1.18-2.17) and HF hospitalization (OR 1.40, 95% CI 1.05-1.86). Compared with non-use, new digoxin use with SDC ≥1.2 ng/mL had higher odds of HF hospitalization and borderline higher odds of death (Table); SDC ≤0.8 ng/mL had higher odds of death. Digoxin use was associated with higher adjusted rates of HF hospitalization and death in men but not in women (Table).

Conclusions:
Digoxin was associated with a higher risk of death and HF hospitalization, however these risks were dependent on SDC. Digoxin was linked to a higher risk of adverse events in men but not significantly so for women.
Abstract 17354: Aortic Stenosis in Women vs. Men: Differential Severity to Calcification Load Relationship
Authors: Aggarwal Shivani R , Messika-Zeitoun David , Cueff Caroline , Maalouf Joseph , Araoz Philip A , Vahanian Alec , Sarano Maurice E
Published: April 2024

Introduction:
Aortic Stenosis (AS) is a common valve disease of the adult, caused by calcification of aortic cusps. The relationship between cusp calcification and severity of AS has been established mostly in men and it is unclear whether the calcification process and its relation to AS severity is similar in women

Hypothesis:
We hypothesized that the physiologic relation between aortic valve calcification (AVC) load and AS severity is different in men and women and that lower calcification loads may lead to severe AS in women

Methods:
We prospectively performed high resolution computed tomography (CT) without contrast in 679 patients with AS (Aortic valve area (AVA) <2cm
2
, Mean gradient ≥10 mmHg) at two academic centers (Rochester, MN; Paris, France) to measure AVC scores and compare these to the hemodynamic obstruction measured by Echo-Doppler.

Results:
Women vs. men were older (76±11 vs 74±11, p<0.0001) with slightly higher ejection fraction (62±12 vs 59±13, p=0.001) but AS severity was similar (AVA/body surface area 0.55±0.2 vs 0.56±0.2 cm
2
/m
2
; Peak velocity 4±1 vs 3.9±1 m/s; Mean gradient 41±21 vs 38±18 mmHg, all p≥0.1). Yet, AVC load was lower in women vs men, score absolute or normalized for LVOT area (551±383 vs 626±399 all p<0.0001). For those with severe AS (Mean gradient >40 mmHg), AVC scores were 2433±1412 in women vs 3805±1587 in men. Multivariate analysis adjusting for age, BSA, LVOT area and mean gradient, confirmed that severe AS was achieved with lower AVC load in women (all p<0.0001).

Conclusions:
In this large multicenter AS population, women reached similar AS severity than males for lower calcium loads, even after adjustment for lower body and LVOT size. Hence the relation between valvular calcification process and severity of AS differs in women vs. men. Thus, future studies are needed to determine the differential mechanism of aortic calcification in men and women and diagnostic consideration must be given to gender in the interpretation of AS severity by AVC load.
Abstract 17406: Inhibition of MicroRNA-133a Expression is Associated with Poor Growth Response of Vascular Smooth Muscle Cells to Insulin-Like Growth Factor-1 in Apolipoprotein-E Deficient Mice
Authors: Gao Song , Wassler Michael , Li Yangxin , Zhang Lulu , Shelat Harnath , Geng Yong-Jian
Published: April 2024

Background and Objective.
Alternations in growth and differentiation of vascular smooth muscle cells (SMC) contribute to the pathogenesis of atherosclerosis. Certain microRNAs (miR) have been shown to regulate cardiovascular cell growth and differentiation. For instance, miR-133a plays a role in cardiac muscle development. However, it is largely unknown if miR-133a affects SMC proliferation in atherosclerosis. This study was designed to analyze miR-133a expression and SMC growth in atherosclerosis and to explore if insulin growth factor (IGF)-1 receptor is involved in the miR-133a effect on SMC growth.

Methods and Results.
qRT-PCR analysis of total RNA extracted revealed lower levels of miR133a in SMC cultured from apolipoprotein E-null (apoE
-/-
) mice than those in wild-type C57BL/6J (WT). Interestingly, IGF-1R mRNA levels were lower in the ApoE
-/-
cells. Immunofluorescence for IGF-1R was positive in both the sections of WT and ApoE
-/-
mice aorta but the latter displayed weaker signals. In cultured WT SMCs, IGF-IR protein expression decreased by about 66% after incubation with miR-133a inhibitor. In contrast, IGF-IR levels increased by almost 3-fold when the cells were treated with miR-133a precursor. Growth curves showed that SMC proliferation was attenuated with miR-133a inhibitor(Fig.1). The decreased SMC proliferation was caused by poor response to IGF-1 as addition of IGF-1 did not increase SMC numbers in the cultures. However, incubation with miR-133a precursor increased proliferation of WT SMC by 25% and ApoE
-/-
SMC by 10%.

Conclusions.
Down-regulation of miR-133a expression with miR-133a inhibitor decreases IGF-1R expression and inhibits the growth of WT SMCs but to a less degree in Apo
-/-
SMC. In contrast, overexpression of miR-133a increases IGF-1R expression and promotes the IGF-1 derived the SMC growth. The data suggest that miR-133a may participate in regulation of SMC growth in atherosclerotic vascular tissue.
Abstract 17419: Differential Roles of Rap1 Isoforms in Regulation of Vascular Permeability and Endothelial Cell Barrier
Authors: Sobczak Magdalena , Chrzanowska-Wodnicka Magdalena
Published: April 2024

Dynamic regulation of vascular permeability is critical for normal vessel function as evidenced in pathological conditions such as edema or inflammation; yet underlying mechanisms are not fully understood. Small G protein Rap1 has been implicated in promoting endothelial cell-cell (EC) junction formation upon elevation of cellular cAMP but also in promoting angiogenic responses to VEGF. However, what role Rap1 plays in regulation of vascular permeability in vivo is not known. The project's objective was to investigate the function of two Rap1 isoforms, Rap1A and 1B, in the formation and maintenance of adherens junctions (AJ) in ECs and in regulation of vessel permeability in vivo. To accomplish this, we used Cre-lox P method and Tie2 promoter to generate endothelial-specific knockout mice deficient in Rap1A (EC-Rap1A KO), Rap1B (EC-Rap1B KO) or partially depleted of both isoforms (EC-Rap1A KO; Rap1B
+/-
). We found that vessel leakage of Evans blue dye was significantly increased only in lungs from EC-Rap1A KO; Rap1B
+/-
mice but not from EC-Rap1B KO mice suggesting that Rap1A is a main isoform promoting vessel barrier. Using bone marrow chimeras we showed that vessel barrier protection by Rap1 is EC-autonomous. In vitro, confocal microscopy revealed that Rap1A-deficiency in ECs led to altered organization of AJs with dispersed β-catenin distribution across AJs in contrast to narrow distribution in control or Rap1B KO ECs, suggesting that Rap1A may regulate endothelial barrier properties by spatially organizing AJ proteins. However, the kinetics of barrier reformation was not altered in Rap1A-deficient ECs, but was slower in Rap1B-deficient ECs, as evidenced by diminished cell monolayer electrical resistance measured by electric cell-substrate impedance sensing (ECIS) and slower VE-cadherin fluorescence recovery at AJs after junction disruption with EGTA. Recovery of β-catenin at cell-cell contacts was slower in Rap1B-depleted ECs also after AJs disruption using VEGF, suggesting that Rap1B may play a role in regulating AJs formation kinetics. Overall, these results suggest that two Rap1 isoforms may play differential roles in ECs: Rap1A is required for vascular barrier maintenance, while Rap1B is involved in dynamic regulation of AJs formation.
Abstract 17436: Co-Existing Mitral Regurgitation in Significant Aortic Stenosis: Adverse Impact on Left Ventricular Geometry, Function and Patient Outcome
Authors: Mehrotra Praveen , Jansen Katrijn , Picard Michael H , Hung Judy
Published: April 2024

Background:
Mitral Regurgitation (MR) often co-exists with aortic stenosis (AS). The impact of MR on left ventricular (LV) parameters and prognosis in severe AS is unclear yet important for clinical decision-making. We sought to determine the effect of co-existing functional MR on LV remodeling, diastolic function, and mortality in patients (pts) with severe AS.

Methods:
Pts with severe AS (aortic valve area (AVA) < 1.0 cm
2
) and LVEF ≥ 55% were searched for in our echo database over 12 months. Primary mitral valve disorders (rheumatic and calcific mitral stenosis (mean gradient >5 mmHg) and prolapse) were excluded. 43 pts with severe AS and co-existing ≥ moderate functional MR (+MR) were compared to 139 pts of similar age with severe AS but ≤ mild functional MR (-MR). Indexed end-diastolic (EDVi), end-systolic (ESVi), and left atrial (LAVi) volumes, LV mass, and diastolic function were measured by 2D and Doppler echo. Mortality was assessed by Social Security death index and adjusted for cardiac risk factors and covariates (Cox regression).

Results:
AVA (0.77 vs. 0.79 cm
2
, p=0.5) and mean aortic gradient (40 vs. 41 mmHg, p=0.5) were similar in both groups while the forward stroke volume index (SVi) (38 vs. 42 mL/m
2
, p=0.009) was lower in +MR. LV mass index (122 vs.103 gm/m
2
, p<0.001), EDVi (57 vs. 53 mL/m
2
, p=0.05), and ESVi (19 vs.16 mL/m
2
, p=0.02) were higher in the +MR group. +MR pts also had a higher LAVi (62 vs. 42 mL/m
2
, p<0.001), pulmonary artery systolic pressure (PASP) (47 vs. 40 mmHg, p<0.001), E/E' ratio (18.6 vs. 15.7, p=0.02), and deceleration time (231 vs. 263 ms, p=0.007). Survival (follow-up of 2.6 yrs) was lower in +MR group (67 vs. 85%, HR 2.9 (95% CI: 1.3 - 6.6, p=0.009).

Conclusions:
Co-existing functional MR in pts with severe AS is associated with adverse LV remodeling, higher PASP and increased mortality. These observations may be due to simultaneous volume and pressure overload despite similar AS severity and have important implications for clinical-decision making.