bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 17440: Sonic Hedgehog Signaling Regulates Myogenic Stem Cells and Acts Upstream of Wnt Signaling During Limb Regeneration
Authors: Singh Bhairab N , Doyle Michelle J , Weaver Cyprian V , Koyano-Nakagawa Naoko Koyano-Nakagawa , Garry Daniel J
Published: April 2024

Appendage regeneration in urodeles such as the newt occurs through formation and maintenance of multipotent progenitors called the blastema. The blastemal progenitors are regulated by the coordinated activity of transcriptional networks and signaling pathways. In the present study, we have investigated the role of sonic hedgehog (Shh) signaling in myogenic stem/progenitor cells during limb regeneration. We show that Shh signaling is essential for the limb regeneration and inhibition of Shh pathway leads to irreversible perturbation of regeneration. Our histological analysis and reversibility experiments suggest that although inhibition of Shh pathway does not affect the dedifferentiation process, it is required for the initial stages of regeneration. Using BrdU incorporation and immunohistochemical analyses, we show that Shh signaling regulates the blastemal cell proliferation, as inhibition of Shh pathway results in a 4-fold reduced labeling of BrdU positive nuclei and results in G0/G1 cell cycle arrest. We further show that limb regeneration is achieved by activation of Pax7
+
myogenic stem cells, and Shh signaling inhibition leads to reduced number of Pax7
+
cells. Importantly, we find that Shh inhibition leads to retarded migration of myoblast cells and reduced proliferation of the activated myoblasts (MyoD
+
cells). Further, we demonstrate using an inhibitor-activator strategy that activation of Wnt signaling could rescue the Shh inhibition. Analysis of cell cycle kinetics reveals that activation of the Wnt pathway in the Shh inhibition background results in increased G2/M populations, concomitant with a 23% increase in BrdU positive cells suggesting that the Wnt pathway is activated later than Shh signaling and modulates cell cycle regulatory networks. Collectively, our results demonstrate the hierarchical regulation of signaling pathways in the regulation of myogenic stem cell populations and limb regeneration.
Abstract 17460: Sildenafil Upregulates Pgc1α and Mitochondrial Function in Advanced Cardiac Hypertrophy Independently of Rgs2 or Leucine-Zipper Function of Pkg1α
Authors: Zhu Guangshuo , Zhang Manling , Kaludercic Nina , Bedja Djahida , Lee Dongik , Sasaki Hideyuki , Yuan Yuan , Koitabashi Norimichi , Paolocci Nazareno , Mendelsohn Michael E , Kass David , Takimoto Eiki
Published: April 2024

Enhanced cGMP-PKG signaling by PDE5 inhibitor, sildenafil (SIL), ameliorates cardiac mal-adaptive hypertrophy/remodeling. Although Gq inhibition via PKG-RGS2 activation is an essential mechanism for the early stage anti-hypertrophy under pressure-overload (TAC) in mice, the mechanism for the advanced disease stage remains unknown. Impaired mitochondrial respiration was observed in advanced stage dilative 9wk TAC hearts, associated with down-regulation of PGC1α and reduced mitochondrial biogenesis (mt cytochrome b/ b-actin DNA), but not in 1-3 wk TAC hearts. Delayed SIL treatment (100mg/kg/day) initiated after hypertrophy establishment (1-3 wk TAC) inhibited progression of remodeling up to 9wks, which was associated with restored PGC1α expression and preserved mitochondrial function, but not with RGS2 activation. RGS2 null (KO) mice or PKG1α leucine zipper mutant knock-in (LZM) mice harboring disrupted RGS2-PKG interaction develop exacerbated early hypertrophy (1wk TAC) which is unresponsive to SIL, whereas SIL initiated after 1wk ameliorated long term (up to 7wk) progression of cardiac remodeling and function, with restored PGC1α expression, mitochondrial biogenesis and improved mitochondrial respiration assessed in cardiac fibers when palmitoyl carnitine (state3 O2 consumption, nmol/min/mg dry fiber, RGS2KO TAC: SIL 13.52±1.68 vs veh 8.47±0.87; LZM TAC: SIL 14.04±1.06 vs veh 8.79±1.27) or glutamate/malate(RGS2KO TAC: SIL 18.69±2.78 vs veh 9.58±0.78; LZM TAC: SIL 15.81±1.66 vs veh 9.68±1.16) was used as substrate. In rat neonatal cardiac myocytes (RNCM), 72hr exposure to phenylephrine (Gq agonist, 20µM) down-regulated PGC1α and impaired mitochondrial respiration, both of which were normalized by SIL co-treatment (1µM). Over-expression of PKG up-regulated PGC1α in RNCM, increasing mitochondrial respiration, whereas this was not observed when PGC1α was silenced. These results suggest enhancing cGMP-PKG signaling by SIL improves cardiac energetics by restoring myocyte PGC1α and thereby ameliorates remodeling progression in advanced stage of pressure-overload hypertrophy, which is independently of RGS2 or LZ function of PKGIa.
Abstract 17480: Strain-Time Curve Analysis by Speckle Tracking Echocardiography in Cardiac Resynchronization Therapy - Insight Into the Pathophysiology of Responders vs. Non-Responders
Authors: To Andrew C , Grimm Richard A , Thomas James D , Wilkoff Bruce L , Agler Deborah A , Marwick Thomas , Popovic Zoran B
Published: April 2024

Background:
Patients who have non-ischemic heart failure etiology, wide QRS complex, and left bundle branch block (LBBB) on ECG show better response to cardiac resynchronization therapy (CRT). While it is widely accepted that these patients have the most pronounced left ventricular (LV) dyssynchrony, echocardiographic methods aimed at quantifying LV dyssynchrony failed to predict outcome. We hypothesized that patients with favorable outcome from CRT have a characteristic strain distribution pattern that singles them out of the others.

Methods:
From 313 CRT patients on our database with long-term echocardiographic follow up, we randomly selected 10 non-ischemic cardiomyopathy patients with LBBB who were CRT responders (LV end-systolic volume (LVESV) reduction at follow-up ≥15%) and 9 patients who were CRT non-responders. Longitudinal (ε
long
) strain data were obtained by speckle tracking echocardiography before and after CRT implantation, 8±5months apart. Standardized segmental ε
long
-time curves obtained by averaging individual patient data were compared before and after CRT.

Results:
In responders, LVESV decreased from 184±74 to 111±63ml and LV ejection fraction increased from 25±9 to 40±11%, (p<0.05 for both). In non-responders, LVESV did not change significantly from 244±115 to 274±113ml and LV ejection fraction from 20±8 to 21±5% (p=ns). Pre CRT septal ε
long
-time curves in both groups showed early septal contraction with mid-systolic decrease, while lateral ε
long
showed early stretch followed by vigorous mid to late contraction (Figure). ε
long
amplitudes are significantly higher in the responder group (p<0.01). Post CRT improvement in ε
long
is significantly worse in the non-responder group.

Conclusion:
While CRT responders and non-responders with LBBB and non-ischemic etiology show a similar strain pattern prior to CRT, significantly lower strain amplitudes in the non-responders may account for their poor response to CRT.
Abstract 17495: Thrombospondin-1/CD36 Pathway Critically Contributes to SHH Signaling Defect and EPC Dysfunction on Wound Healing in Type 1 Diabetes
Authors: Wang Jie-Mei , Isenberg Jeffery S , Chen Alex F
Published: April 2024

Introduction:
Refractory wounds in diabetic patients is a significant clinical problem. We reported previously that sonic hedgehog (SHH), a morphogenic protein central to wound repair, is deficient in diabetes, but the underlying mechanisms are poorly understood. We hypothesized that thrombospondin-1 (TSP-1) through its receptor CD36 contributes to SHH signaling defect in cutaneous tissue and endothelial progenitor cells (EPCs), resulting in impaired wound healing in type 1 diabetic mice.

Methods and Results:
Cutaneous expression of SHH and its signaling molecules including Patched (Ptc), Smoothened (Smo), and Gli were significantly decreased in streptozotocin (STZ)-induced type 1 diabetic mice (male, C57BL/6J, 12 weeks) vs. their age-matched control littermates (Western blot analysis, n=5, p<0.05 vs. control), which were reversed in STZ-treated TSP-1
-/-
mice (homozygote, C57BL/6J background, n=5, p<0.05 vs. STZ-treated WT mice). Excisional wound (6-mm punch biopsy) closure was significantly delayed in STZ mice (n=6, p<0.05 vs. control) with reduced wound blood flow (Laser Doppler), which was not observed in STZ-treated TSP-1
-/-
mice (n=5, p<0.05 vs. STZ-treated WT mice). The protective effect of TSP-1 depletion on wound repair was abolished following topical treatment with the selective SHH inhibitor cyclopamine (5 μ M, 30 min/day, n=5, p<0.05 vs. STZ-treated TSP-1
-/-
mice). Isolated EPCs from bone marrow of STZ mice showed significantly impaired angiogenesis (Matrigel tube formation, n=4, p<0.05 vs. control), which was rescued by exogenous SHH (1 mg/L, 24 hours, n=4, p<0.05 vs. STZ-control). Increased EPC angiogenesis in STZ-treated TSP-1
-/-
mice (n=5, p<0.05 vs. STZ-WT) was inhibited by the selective SHH inhibitor cyclopamine (5 μ M, 24 hours, n=5, p<0.05). SHH, Ptc, Smo and Gli levels were significantly increased in EPCs from TSP-1
-/-
mice and CD36
-/-
mice, but not CD47
-/-
mice (n=6, p<0.05 vs. WT). Normal EPCs treated with recombinant human TSP-1 protein (2.2 nM, 24 hour) exhibited impaired angiogenesis, an effect that was not observed in EPCs from CD36
-/-
mice (n=5, p<0.05).

Conclusion:
TSP-1/CD36 pathway critically contributes to SHH signaling defect, resulting in EPC dysfunction and impaired wound healing in type 1 diabetic mice.
Abstract 17534: HIV-Infected Patients Exhibit a Worse Cardiovascular Risk Profile After a First Episode of Acute Coronary Syndrome
Authors: Boccara Franck , Mary-Krause Murielle , Teiger Emmanuel , Lang Sylvie , Lim Pascal , Wahbi Karim , Beygui Farzin , Milleron Olivier , Steg Philippe Gabriel , Funck-Brentano Christian , Slama Michel , Girard Pierre-Marie , Costagliola Dominique , Cohen Ariel
Published: April 2024

Purpose:
The PACS-HIV study was designed to determine the 3-year prognosis of acute coronary syndrome (ACS) in HIV-infected patients (HIV+) as compared to HIV- in a prospective observational study. We report the cardiovascular risk profile after the index ACS.

Methods:
We enrolled 103 HIV-infected and 195 HIV-uninfected patients with a first episode of ACS matched for age (± 5 years), sex, and type of ACS. During follow up, cardiovascular risk factors including lipid parameters, tobacco consumption were collected. Univariate conditional logistic regression was used to compare variables and stratified multivariate Cox models were performed.

Results:
The mean age at enrolment was 49.0 ± 9.4 years and 94% were men. At admission, coronary risk factors were well balanced between the 2 groups except for a higher rate of illicit drug used and hypertriglyceridaemia in the HIV+ group. At 3-year follow up, HIV+ patient exert a higher rate of recurrent ACS as compared with HIV- patients (univariate HR 3.4; 95% CI [1.3-8.8]). At long term, HIV+ exhibit a worse cardiovascular risk profile with more smokers and worse atherogenic lipid profile (Table). Incident cases of hypertension and diabetes tend to be higher in the HIV+ group (16.2/1000 persons per year (PY) vs 9.1/1000 PY, RR (HIV+ / HIV-)=1.8, IC
95%
=[0.4-7.1] 41.0/1000 PY vs 21.9/1000PY, RR (HIV+ / HIV-)=1.9, IC
95%
=[0.8-4.3], respectively). Stratified multivariable Cox model showed that HIV status, total cholesterol and LDLc were associated with the recurrence of ACS (Table).

Conclusions:
At long-term follow-up after ACS, HIV+ exhibit higher residual cardiovascular risk. HIV infection and atherogenic lipid profile were associated with an increased risk of ACS. Secondary prevention should focus on smoking cessation and strict LDL goal in HIV+.
Table. Cardiovascular risk factors at 3-year follow Multivariate analysis associated with increased risk of recurrent ACS
Values expressed as n (%) , *time-dependent covariates
Abstract 17551: The Impact of Ordering Provider Specialty on Appropriateness Classification
Authors: Carryer Damita J , Askew John W , Hodge David O , Miller Todd D , Gibbons Raymond J
Published: April 2024

The Impact of Ordering Provider Specialty on Appropriateness Classification In prior studies, our laboratory applied the ACCF/ASNC AUC for SPECT MPI to several cohorts of patients in Mayo Clinic Rochester. The purpose of this study was to re-examine our data to test the hypothesis that the specialty of the ordering provider affected the appropriateness.

We compared the ordering providers specialty with appropriateness determined in prior studies. The study group consisted of 281 patients who underwent stress SPECT MPI studies in May 2005 and 282 patients in October 2006 (before any quality improvement initiatives were begun at Mayo). Appropriateness categories were assigned by 2 experienced nurses from the CV Research Studies Unit not affiliated with the nuclear laboratory. Patients who were studied for pre-operative evaluation (n = 20) or post myocardial infarction (n = 7) were excluded because they comprised less than 5 percent of the patients. Pre-operative testing in our institution is done primarily by stress echocardiography. The final study group consisted of 526 patients.

Excluding the 64 unclassified patients, AUE categories were appropriate (75 %), uncertain (13 %), inappropriate (12%). Results by ordering provider are shown in the figure, where CV = Cardiovascular MDs, ED = Emergency Department MDs, IM = General and Internal Medicine MDs, RN = Registered Nurses, and SP = other Specialty MDs. There was no significant association (p = 0.19); Chi-square analysis between appropriateness and specialty groups.

In a clinical practice where pre-operative testing using SPECT is infrequent, the rate of inappropriate studies was similar for all ordering providers. Quality improvement efforts in similar practices will likely require a broad focus on all ordering physicians/nurses.
Abstract 17678: The Correlation Between Collagen Degradation and LV Function Following Induction of Beta-Blocker Therapy
Authors: Yoshida Chikako , Hirotani Shinichi , Goda Akiko , Masaki Mitsuru , Otsuka Misato , Nakaboh Ayumi , Eguchi Akiyo , Lee-Kawabata Masaaki , Tsujino Takeshi , Masuyama Tohru
Published: April 2024

Objectives:
Beta-blocker therapy inhibits LV remodeling, and improves not only LV systolic function but also LV diastolic function, and improves prognosis of heart failure patients. But it is unknown why beta-blocker therapy improves LV function. Recently, serum collagen markers such as Procollagen type I C-terminal propeptide (PICP) and collagen type I C-terminal telopeptide (CITP), are useful as index of myocardium collagen synthesis and degradation. We investigate correlation between collagen turnover and LV function following induction of beta-blocker therapy with systolic heart failure patients.

Methods:
Study population consisted of 46 patients with systolic heart failure. Patients were clinically stable within 1 month and on stable medical therapy, including ACEI or ARB and diuretics, and no beta-blocker therapy. We started beta-blocker therapy, initiated at a target dose of from 5 to 10mg/day. Echocardiography was performed before, 2, 6, and 12 months after the initiation of beta-blocker therapy. LV systolic function was estimated using the LV ejection fraction by Simpson biplane method. Peak systolic strain in the radial direction was measured at the anterior and posterior walls in the short-axis view. We measured E- and A-wave peak velocities and deceleration time (DcT) form the mitral inflow profile, and tissue Doppler early diastolic mitral annular velocity (E'). Serum PICP and CITP were determined.

Results
(table): A total of 46 patients were enrolled. The median age of all patients was 56±14 years. 15 patients were women and 31 patients were men. EF, DcT and E' were improved after induction of beta-blocker therapy. PICP was not changed, but CITP was decreased from 8.9±7.8 to 6.1±1.7ng/ml at 12 months after treatment. The lower %changes in CITP was associated with the higher %changes in DcT (r=0.21, p<0.05), EF (r=0.29, p<0.01) and radial systolic strain (r=0.26, p<0.05), but not E'. The %changes in PICP were not related %changes in DcT and E'.

Conclusions:
The improvement in LV systolic function as indexes in EF and radial systolic strain and LV diastolic stiffness as indexes in DcT, correlated with inhibition of collagen degradation in patients with LV systolic function.
Abstract 17718: Right Ventricular Assist Device Removal in Patients with Apparently Unloading-Promoted Improvement of Right Ventricular Function: Criteria for Weaning Decisions
Authors: Dandel Michael , Potapov Evgenij , Krabatsch Thomas , Stepanenko Alexander , Siniawski Henryk , Knosalla Christoph , Lehmkuhl Hans B , Hetzer Roland
Published: April 2024

Background:
The complex right ventricular (RV) geometry and load dependency of indices used to quantify its function make RV assessments very challenging. Differences between right and left ventricular (LV) geometry, wall thickness, myofiber architecture, blood supply and load dependency of myocardial function, limit the use of data obtained from LV studies for RV assessment. The reliability of criteria used for weaning decisions in patients with a RV assist device (RVAD) is barely known. We assessed this issue.

Methods:
In 36 patients who were weaned from mechanical RV support since 2003 we analyzed echocardiographic data on RV size, geometry and function plus the data on pulmonary hemodynamics recorded during “off-pump” trials. The final goal was to identify the parameters with the highest predictive value for post-weaning stability of RV function. Wall motion velocity was measured by pulsed-wave tissue Doppler.

Results:
Of 36 evaluated patients, 19 were weaned from “short term” bridge to recovery designed RVADs and 17 from bridge to transplant designed biventricular assist devices (BVADs). Post-weaning right heart failure (RHF) recurrence occurred in 6 (16.7%) patients. Of these 6 recurrences, 4 occurred after BVAD removal and 2 after the removal of short term designed RVADs. To date 25 patients have already reached between 1 and 7 years of post-weaning RV stability. During final off-pump trials performed before RVAD removal all 36 patients had RV ejection fraction (RVEF) > 45%, stable central venous pressure at values ≤ 12 mm Hg and ≤ grade 2 tricuspid regurgitation (TR). The mean pulmonary arterial pressure was between 18 and 30 mmHg. Off pump RV long/short axis ratio (L/S) < 0.55 and the tricuspid annulus peak systolic velocity (TAPSm) > 8 cm/s showed the highest predictive value for > 1 year stable RV function after weaning (89.5% and 94.4%, respectively). In patients without elevated pulmonary vascular resistance both TAPSm ≤ 8 cm/s and L/S ≥ 0.55 appeared to be risk factors for early recurrence of RHF.

Conclusion:
RV geometry and the velocity of RV systolic wall motion during off pump trials in patients with RVEF ≥ 45% and without relevant TR are highly predictive for a stable RV function after RVAD removal.
Abstract 17729: Cumulative Effect of Echocardiographic Markers of Elevated Left Ventricular Filling Pressure on Future Cardiovascular Events in Subjects with Diabetes
Authors: Wai Bryan , Patel Sheila K , Ord Michelle , Srivastava Piyush M , Burrell Louise M
Published: April 2024

Background:
Type 2 diabetes mellitus (T2DM) is a strong and independent risk factor for the development of major adverse cardiovascular events (MACE). An elevated left ventricular filling pressure (LVFP) measured by various echocardiographic (echo) parameters is associated with poor outcomes. This study investigated the cumulative effect of various echo measures of elevated LVFP and the risk of MACE.

Methods:
We prospectively recruited 1308 subjects (subs) (age 63.5± 11.7 years, 60% male) with T2DM attending a complications surveillance program at a single tertiary center (21 subs excluded due to inadequate echo imaging). Baseline resting echocardiogram was performed and subs were followed for a median of 4.4 years [interquartile range 3.2, 5.9]. Elevated LVFP was defined by the following echo measures: left atrial area > 20cm2, peak early diastolic (dia) mitral velocity (E) to peak mitral annular velocity ratio ≥ 10, pulmonary vein (PV) peak dia velocity > systolic velocity, peak PV atrial reversal >35cm/s, PV atrial reversal duration minus late dia mitral inflow wave duration >30msec and mitral E/A change >/= 0.5 with Valsalva. The primary outcome was MACE defined as hospitalization for acute coronary syndrome, stroke or heart failure, coronary or peripheral vessel revascularization or death.

Results:
Over the follow-up period, 27% of subs experienced at least one MACE and 15% experienced heart failure or death. After adjusting for age, gender, presence of macrovascular complications and cardiovascular risk factors, each additional echo measure of elevated LVFP was associated with a 29% increased risk of MACE. After the same covariate adjustment, subs with >3 measures of elevated LVFP had a higher hazard ratio of 2.7 (95% CI 1.9-3.8, P<0.001) for MACE compared to subs with <2 measures of elevated LVFP.

Conclusions:
Echo features of elevated LVFP predict future MACE. The presence of >3 features of elevated LVFP is associated with poorer outcomes in T2DM.
Abstract 17754: Accuracy of Dual Source Computed Tomography to Predict Suitable Angulations for Fluoroscopic Guidance During Transcatheter Aortic Valve Implantation (TAVI)
Authors: Achenbach Stephan , Ensminger Stephan , Bauer Ina , Ludwig Josef , Feyrer Richard , Daniel Werner G , Weyand Michael , Einhaus Friedrich , Marwan Mohamed , Nef Holger , Hamm Christian , Arnold Martin
Published: April 2024

For Transcatheter Aortic Valve Implantation (TAVI), optimal selection of fluoroscopic projections is important and often requires multiple aortic angiograms in various angulations. We analyzed the ability of Dual Source CT (DSCT) to predict suitable angulations for fluoroscopy during the TAVI procedure, including influence on procedural parameters and contrast use.

Methods:
75 consecutive patients who underwent TAVI using the Edwards-Sapien valve were evaluated. Possible angulations which would render an orthogonal view onto the aortic valve plane were determined by interactive evaluation of pre_procedural contrast-enhanced DSCT data sets acquired during i.v. injection of 40ml contrast agent. TAVI operators used a predicted angulation for the first aortic angiogram and performed additional aortic angiograms if no satisfactory view of the valve plane was obtained. Predicted angulations were compared to the angulation used for valve implantation. Differences of less than 5° (sum of LAO-RAO and CRAN-CAUD deviation) were considered as accurate prediction. Radiation exposure and contrast use was compared between patients with accurate prediction of fluoroscopic angulations by CT versus those in whom CT failed to predict a suitable view. Aortic valve calcifum was visually quantified in CT as mild, moderate, severe.

Results:
TAVI was successful in all 75 patients. The mean difference between the CT-predicted angulation and the angulation used for implantation was 3±6°. CT predicted a suitable angulation in 63/75 cases (84%). The number of aortic angiograms acquired in patients with correct prediction (1.02±0.1) was lower than in patients with incorrect prediction (3.0±1.7, p < 0.001). Similarly, the amount of contrast agent required for the entire TAVI procedure was lower in patients with correct prediction (72±36ml vs. 106±39 ml, p = 0.001). Extensive calcifications of the aortic valve were associated with a lower frequency of correct prediction (100% for mild, 89% for moderate, and 71% for severe calcification, p = 0.03).

Conclusion:
CT allows prediction of suitable fluoroscopy angulations during TAVI in the majority of cases, which significantly reduces the required amount of contrast.
Abstract 17763: Multiple Reaction Monitoring-Based, Multiplexed, Absolute Quantitation of 82 Putative Biomarkers of Cardiovascular Disease in Human Plasma
Authors: Domanski Dominik , Smith Derek S , Miller Christine A , Cohen-Freue Gabriela , Hill John S , Parker Carol E , Borchers Christoph H
Published: April 2024

Multiplexed biomarker expression profiling of clinical samples can be achieved in a rapid and targeted fashion using mass spectrometry-based multiple reaction monitoring (MRM) quantitation. For this project, a mixture of ~230 peptides standards was created to permit absolute quantitation of 82 putative biomarkers of cardiovascular disease, in human plasma trypsin digests. All experiments were performed on simple tryptic digests of human EDTA-plasma without prior affinity depletion or enrichment. Synthetic purified stable isotope-labeled standard peptides (SIS peptides) were added to the samples after tryptic digestion. For maximum specificity, a high-flow system using UPLC and an Agilent 6490 triple quadrupole mass spectrometer, equipped with an ion-funnel sprayer, were used. Instrumental parameters were empirically determined in order to generate the most abundant precursor ions and ion fragments. The narrow UPLC peak shapes and reproducible retention times assisted in the development of the highly-multiplexed system by increasing the chromatographic “space”. In addition, the larger id column, with a larger amount of packing material, also provided increased “robustness” of the overall system, as demonstrated by 110 analyses of the same sample with no loss of sensitivity or retention time accuracy. Linear responses and lowest limits of quantitation were obtained for all proteins. Sensitivities using the new system were in the low attomole range demonstrating that the high-flow system, which allowed loading more protein digest onto the column, more than compensated for any reduction in electrospray ionization efficiency caused by the higher flow rate. Concentrations of individual peptide standards in the mixture were optimized to approximate endogenous concentrations of analytes for the highest quantitation accuracy. The analytical precision was assessed for each protein assay from LC-MRM/MS analyses performed on 3 different days on different batches of plasma tryptic digests, and was found to be within 10%. Concentrations of proteins were compared to reported literature values. This method, with the same mixture of internal standards, is now being used for the plasma protein expression profiling of cardiovascular disease patients.
Abstract 17878: Kindlin-2 is a Novel Regulator of Hemostasis
Authors: Pluskota Elzbieta , Szpak Dorota , Ma Yi , Ma Yan-Qing , Soloviev Dmitry A , Byzova Tatiana , Dowling James J , Golden Jeffrey A , Nestor Carla , Podrez Eugene A , Plow Edward F
Published: April 2024

Kindlin-2, a widely distributed cytoskeletal protein, has been implicated in integrin activation, and its absence is embryonically lethal in mice. We previously demonstrated that kindlin-2 is a key contributor to angiogenesis since it was defective in

kindlin-2
+/-

mice and zebrafish. In the present study, we tested the hypothesis that kindlin-2 may regulate hemostasis utilizing the
kindlin
-2
+/-
mice. Tail bleeding time was significantly prolonged (+ 45%, P=0.02) and blood loss was 4-fold more (P=0.005) in

kindlin-2
+/-

mice as compared to WT animals. In addition, time to carotid artery occlusion after FeCl
3
injury was increased by 30% (P=0.02) in the

kindlin-2
+/-

mice. Fibrinogen, vWF, t-PA, TFPI levels or activities were similar in plasma of WT and

kindlin-2
+/-

mice. Platelet count, platelet expression levels of integrin αIIbβ3, P-selectin and GPIbα as well as ex vivo platelet aggregation in response to various agonists were similar in both mouse strains. Bone marrow transplantation from

kindlin-2
+/-

donors to WT mice did not transfer the bleeding prolongation to recipients, indicating the defect was not associated with bone marrow-derived cells in

kindlin-2
+/-

mice. However, mouse aortic endothelial cells (ECs) isolated from the

kindlin-2
+/-

mice showed significantly enhanced capacity to inhibit ADP-induced platelet aggregation as compared to WT ECs (75% platelet aggregation in the presence of WT ECs vs 20% aggregation in the presence of

kindlin-2
+/-

ECs). Although eNOS expression and phosphorylation were similar in both WT and

kindlin-2
+/-

ECs, FACS analyses revealed increased (by 2-3-fold) levels of ATP diphosphohydrolase (CD39) and Ecto-5’-Nucleotidase (CD73) on the surface of the

kindlin-2
+/-

ECs. Accordingly, 2-3 fold more ADP and AMP were hydrolyzed on

kindlin-2
+/-

ECs than on WT ECs, and supernatants collected from ADP-treated

kindlin-2
+/-

ECs did not trigger platelet aggregation as efficiently as those from WT cells. In control experiments, overexpression of kindlin-2 in the

kindlin-2
+/-

EC, decreased CD39 and CD73 levels and blunted the antiplatelet activities of these cells. Taken together, endothelial kindlin-2 regulates ADP levels and ADP-dependent platelet responses and, thereby, plays an important role in thromboregulation.
Abstract 17884: Ventricular Sympathetic Innervation in Patients with Transposition of the Great Arteries After Arterial Switch- and Rastelli Procedure, - Impact of Arterial Dissection and Coronary Reimplantation
Authors: Hauser Michael , Kühn Andreas , Hess John , Schwaiger Markus , Bengel Frank M
Published: April 2024

Objectives:
Coronary flow reserve is significantly reduced in patients with transposition of the great arteries (TGA) after arterial switch operation (ASO). Dissection of the great arteries and coronary reimplantation may result in partial myocardial sympathetic denervation, with a negative influence on coronary blood flow.

Methods:
18 patients with TGA were included in the study; 9 had ASO (age 20.8 + 5.8 years), controls were 9 patients after Rastelli procedure (22.1 + 6.8 years). All patients were fully active and asymptomatic. Sympathetic innervation was measured by positron emission tomography using
11
C hydoxyepinephrine (HED).

Results:
Myocardial perfusion at rest was homogenous in all patients. Maximal left ventricular myocardial HED retention as a measure of the intensity of innervation ranged from 6.1% to 15.9% (mean 12.74 + 3.8% per minute). Patients with more than one operation had significant reduced maximal HED retention (r=2.99, p<0.001); one patient of each group had HED-retention less than 7% indicating complete denervation. A significant correlation with time after surgery could be found for max. HED retention (r=0.326, p<0.001); max. HED retention was higher in patients undergoing corrective cardiac surgery at an earlier age (r=0.315, p<0.001). No statistical significant difference could be found between patients after ASO and Rastelli procedure. Aortic cross clamp time was inversely correlated with max. HED retention (r=-2.94; p<0.001).

Conclusion:
Coronary reimplantation and dissection of the great arteries have a negative influence on the sympathetic innervation of the myocardium, but because of reinnervation maximal myocardial blood flow is not essentially altered by this mechanism in older patients. Open heart surgery and prolonged aortic cross clamp time have a negative influence on the norepinephrine content of cardiac sympathetic nerve terminals.
Abstract 17890: Cardiomyocyte-Specific ATGL Over-Expression Prevents Doxorubicin-Induced Cardiac Dysfunction in Female Mice
Authors: Nagendran Jeevan , Kienesberger Petra C , Pulinilkunnil Thomas , Dyck Jason R
Published: April 2024

Anthracyclines such as, doxorubicin (DOX) are an effective class of antineoplastic agents. Despite its efficacy in the treatment of a variety of cancers including breast cancer, the clinical use of DOX is limited by cardiac side effects. While it has been shown that DOX alters myocardial fatty acid metabolism, it is poorly understood whether variations in myocardial triacylglycerol (TG) metabolism contribute to DOX-induced cardiotoxicity. Since TG catabolism in the heart is primarily controlled by adipose triglyceride lipase (ATGL), this study examined the influence of DOX on cardiac ATGL expression and TG levels as well as the consequence of forced-expression of ATGL in the setting of DOX-induced cardiotoxicity. To do this, wild type (WT) mice and mice with cardiomyocyte-specific ATGL over-expression (MHC-ATGL) received weekly intraperitoneal injections of saline or DOX (8mg/kg) for four weeks. Heart rate, heart weight to tibia length ratio and DOX-induced body weight loss were comparable between genotypes. As expected, myocardial TG content was significantly reduced in MHC-ATGL mice compared to the WT following DOX treatment. Echocardiographic analysis also revealed a significant reduction of systolic heart function (% ejection fraction) in DOX-treated WT mice (saline, 54.6 ± 3.6 vs. DOX, 47.1 ± 1.0, p<0.05), an effect that was not observed in DOX-treated MHC-ATGL mice (saline, 58.7 ± 2.6 vs DOX, 57.2 ± 2.4, p = 0.7). The wet to dry lung weight ratio was increased in DOX-treated WT (saline, 10.1 ± 0.9 vs. DOX, 14.0 ± 1.0, p<0.05), but not MHC- ATGL mice (saline, 9.6 ± 0.6 vs. DOX, 10.9 ± 0.2, p = 0.12), suggesting a protection from pulmonary signs of heart failure. Surprisingly, the preservation of cardiac function in MHC-ATGL mice following DOX treatment was associated with decreased protein expression of PPARα, Oxpat, CD36, and FATP1 as well as increased phosphorylation of acetyl CoA carboxylase when compared to DOX-treated WT mice, indicating a reduction of fatty acid uptake and subsequent oxidation in the cardiomyocyte. Taken together, our data suggest that chronic reduction in myocardial TG content by cardiomyocyte-specific ATGL over-expression is able to prevent DOX-induced cardiac dysfunction.
Abstract 17934: MicroRNA-223 Regulates Macrophage Polarization and Protects Mice from Diet-Induced Insulin Resistance and Adipose Tissue Inflammation
Authors: Zhuang Guoqing , Meng Cong , Guo Xin , Xu Hang , Wang Gang , Li Honggui , Shi Lei , Wu Chaodong , Zhou Beiyan
Published: April 2024

Macrophage-mediated adipose tissue inflammation is a crucial contributor to the risk of Cardiovascular disease (CVD) associated obesity. microRNAs are important regulators for various basic cell functions, such as proliferation, differentiation and apoptosis. We found that miR-223, a microRNA with high abundance in the bone marrow, can regulate adipose tissue inflammation by modulating macrophage polarization. In order to elucidate how miR-223 regulates the function of macrophages, we generated bone marrow-derived macrophage (BMDM) and tested their response to different stimuli. Our results showed that miR-223 deficiency did not affect macrophage formation in mice. However, miR-223 deficiency enhanced the classical activation (M1) but delayed alternative activation (M2) in macrophages. When stimulated by LPS, miR-223
-/-
BMDMs exhibited stronger response compared to wild type control cells at various time points, accompanied by increased phosphorylation of p65, suggesting enhanced NF-κB signaling. On the contrary, alternative stimulation by IL-4 led to delayed response in BMDM with miR-223 deficiency judged by surface marker detection using FACS analysis. Consequently, co-culture of miR223-deficient macrophages with wild-type adipocytes led to increased adipocyte inflammatory response and decreased insulin signaling. In addition we investigated the modulation of adipose tissue inflammation by miR-223 in vivo. Upon high-fat diet (HFD) feeding, miR223-deficient mice exhibited a greater increase in the severity of systemic insulin resistance compared to wild-type littermates. Additionally, miR223-deficient mice exhibited a marked increase in HFD-induced adipose tissue inflammatory response. Using a combination of computational prediction and luciferase reporter assays, we identified several genes that are crucial for macrophage activation as miR-223 targets, including Nfat5 and Pknox1. Our findings suggest that miR223 protect against diet-induced adipose tissue inflammatory response by modulating macrophage polarization. thus provides a new layer of regulatory circuit in the network governing adipose tissue inflammation.
Abstract 17961: Endocardial Defibrillation is Associated with Transient Wall Motion Abnormalities and Significant Pathology Findings in the Domestic Pig
Authors: Torres-Heisecke Raul , Wight-Carter Mary , Riegel Matthew , Joglar Jose
Published: April 2024

Introduction:
Implantable cardioverter defibrillators (ICD) improve overall survival in systolic heart failure human patients. However, ICD therapy by means of defibrillation is associated with a slightly higher mortality risk (for appropriate and inappropriate therapies). With the aim to define objective wall motion and histological changes associated with defibrillation and create a working model for future research and to determine parameters for safe defibrillation, we conducted the following study.

Methods:
To isolate the effects of defibrillation, five healthy domestic pigs (Sus scrofa) with average weight 155 lbs successfully received an ICD system, with pulse generator implanted in the left suprathoracic area and a 7Fr. dual coil right ventricular endocardial lead. Testing was conducted in sinus rhythm and under general anesthesia. With a B->AX vector, two subjects got one ”single” 35 J biphasic shock, two got ten 35 J biphasic shocks (“storm”) as fast as the capacitors were able to charge and deliver therapy and one subject was used as control. The subjects underwent transthoracic echocardiography to assess wall motion before, after and one week later prior to euthanasia. An autopsy was performed at that time.

Results:
Septal wall motion abnormalities were noted in all subjects after defibrillation with complete resolution within 15 minutes. Autopsy showed no macroscopic changes one week after testing. The right ventricles that received therapy showed multiple islands of hypereosinophilic and vacuolated degenerate myofibers that were transmural and adjacent to each other. Left ventricles showed some scattered hypereosinophillic degenerate myofibers. Control subject showed rare hypereosinophillic degenerate myofibers.

Conclusions:
Endocardial defibrillation is associated with reversible short term post therapy delivery changes in local wall motion and significant histopathological changes related to scarring and degeneration in both ventricles one week after therapy delivery in the domestic pig. Further studies are needed to assess the potential relationship of these findings with clinical outcomes and to determine thresholds for myocardial damage.
Abstract 17966: The Roles of S-Phase Kinase-Associated Protein-2 and Mitochondrial Dysfunction in the Aging-Related Endothelial Progenitor Cell-Cycle Retardation
Authors: Wu Yih-Jer , Wang Hsueh-Hsiao , Shu Kuo-Tung , Liu Wen-Ting , Wei Yau-Huei , Yeh Hung-I
Published: April 2024

Background
Deceleration of cell-cycle progression is a prominent feature of cellular senescence. S-phase kinase-associated protein-2 (Skp2) is a subunit of SCF
Skp2
ubiquitin ligase responsible for ubiquitination and subsequent degradation of many cell-cycle regulators, such as cyclin-dependent kinase inhibitors p27
Kip1
and p21
Cip1
, and therefore is a key mediator for G1-S progression. However, it remains poorly understood whether Skp2 regulation and mitochondrial dysfunction are associated with endothelial progenitor cell (EPC) senescence.

Materials and Methods
In vitro
EPC senescence was induced by serial passages. Bone marrow mononuclear cells from bone marrows (BM-MNC) of young (3 months) and old (24 months) rats were served as
in vivo
model of aging.

Results
Senescent EPC had a significantly longer cell doubling time, along with a typical increase of senescence-associated β-galactosidase (SA-βGal) activity and the enhanced expression of aging-related proteins, such as p21
Cip1
and p16
INK4a
. In line with a slow-down of S-phase entry, aging EPC demonstrated a graded downregulation of Skp2 expression. Compared with young EPC, old EPC demonstrated a more elongated mitochondrial network along with a reduction of ATP production. Mitochondrial fission protein Fis-1 was found to be remarkably reduced in old EPC and silencing Fis-1 in young EPC resulted in an elongated mitochondrial network and a reduced ATP level similar to those of old EPC. However, Skp2 levels were not affected by Fis-1 silence, suggesting a mitochondria-independent regulation. Surprisingly, adenovirus-mediated Skp2 expression significantly reversed SA-βGal activity and almost completely rescued old EPC proliferation back to the level of young EPC, though Fis-1 levels and ATP production were not affected. Bone marrow blood from old rats had significantly reduced CD34
+
/KDR
+
cells. Importantly, Skp2 expression in BM-MNC from old rats was also able to reverse SA-βGal activity and cell proliferation.

Conclusion
Skp2 downregulation and mitochondrial dysfunction develop with EPC senescence. Skp2 expression reverses SA-βGal and cell proliferation in old EPC and in old rat BM-MNC. Skp2 is at least one of the important factors that may rejuvenate senescent EPC.
Abstract 17969: Coronary Plaque Composition in Symptomatic African American and White Patients: Insights From with Coronary CT Angiography
Authors: Al-Mallah Mouaz , Qureshi Waqas , Abdul Nour Khaled , Swadia Tanmay , Nasir Khurram
Published: April 2024

Background:
Despite worse cardiovascular outcomes, previous studies have demonstrated that African American (AA) patients have lower coronary calcium score (CCS) compared to Caucasians (CA). The aim of this analysis is to assess the racial differences in coronary plaque burden and composition in symptomatic patients undergoing coronary CT Angiography (CCTA).

Methods:
A total of 838 symptomatic patients (47% male, mean age: 57±12years) underwent CCS and CCTA for evaluation of chest pain syndrome. Each coronary artery segment was evaluated for the presence of and type (calcified, non-calcified, mixed) of atherosclerotic plaque. Presence and extent of atherosclerotic plaque was compared between AA and CA patients using multivariate regression.

Results:
African American patients (n=325) were more often males with higher prevalence of diabetes (23% vs. 18%, p=0.044) and hypertension. They less often had any detectable coronary calcifications (46% vs. 55%, p=0.01) as well as lower median CCS score (0 vs. 10, p<0.0001). In univariate analysis, AA patients had a lower prevalence of calcified plaque (34% vs. 42%, p=0.033) with no differences in non-calcified and mixed plaques (Figure). This continued to be significant after adjusting for potential confounders. (OR of AA having more than 2 calcified plaques compared to CA: 0.52, 95%-CI: 0.34 - 0.83, p=0.007).

Conclusion:
Our analysis suggests that in comparison to Caucasians, symptomatic African-American patients have lower burden of calcified plaque without increase in the presence of non-calcified plaque or mixed plaques as detected by CCTA.
Abstract 17989: Generator Exchange is Associated with an Increased Rate of Sprint Fidelis Lead Failure
Authors: Lovelock Josh , Mengistu Andenet , Hoskins Michael , El Chami Mikhael , De Lurgio David , Langberg Jonathan
Published: April 2024

Background:
The Medtronic Sprint Fidelis defibrillator lead is at an increased risk for failure and was recalled in October 2007. Approximately 268,000 leads were implanted and more than 100,000 patients still have active Sprint Fidelis leads. A number of studies have examined the rate and clinical predictors of lead failure, but none have addressed the effect of ICD generator exchange on subsequent lead failure. Although the manufacture claims that “Sprint Fidelis performance after device change-out is similar to lead performance without device change-out,” published data is lacking.

Objective:
The purpose of this study is to assess the effect of ICD generator exchange on the rate of Sprint Fidelis lead failure.

Methods:
A retrospective chart review was conducted in all patients who underwent implantation of a Sprint Fidelis lead at one academic medical center. All patients who had a normally functioning Sprint Fidelis lead at the time of generator exchange and elected to retain the lead were compared to controls with leads implanted for a comparable amount of time who did not undergo ICD replacement.

Results:
668 patients received a Sprint Fidelis lead prior to the recall. 42 patients with a functioning lead underwent generator exchange without lead replacement. Following generator replacement, 4 leads failed within 3 months and an additional 4 within 1 year (19%). In comparison, 41 of 626 control leads malfunctioned during the study period, a total of 6.5%. Generator exchange significantly increased the rate of lead failure (19% vs. 6.5%, p < 0.05).

Conclusions:
Generator exchange is associated with a higher than expected rate of Fidelis lead failure, often within 3 months. These data suggest that the benefit-risk ratio of Fidelis lead replacement at the time of ICD generator exchange may be greater than previously appreciated and that increased frequency of monitoring may be appropriate when the lead is retained.
Abstract 18008: The Burden and Morphology of Premature Ventricular Contractions in Patients Undergoing Cardiac Resynchronization Therapy
Authors: Aktas Mehmet K , Mittal Suneet , McNitt Scott , Polonsky Slava , Steinberg Jonathan S , Moss Arthur J , Zareba Wojciech
Published: April 2024

Introduction:
Frequent premature ventricular contractions (PVC's) limit effective delivery of cardiac resynchronization therapy (CRT). However, neither the burden nor morphology of PVC's is well defined in patients with ischemic (ICM) and non-ischemic (NICM) cardiomyopathy.

Methods:
In MADIT-CRT, 947 patients enrolled in the CRT-D arm underwent 24-hour 12-lead Holter monitoring. Patients with >5000 PVC's were identified and the morphology of PVC's in each of these patients was assessed. Based on previously published ECG criteria, we characterized PVC's to originate from the RV or LV outflow tract, sinus of Valsalva, or a non-outflow tract location.

Results:
A total of 146 (15%) patients were identified, of whom 88 (60%) had ICM and 58 (40%) had NICM. The median total PVC count in ICM patients was 8807 as compared to 8950 in NICM patients, p=NS. PVC's with a LBBB morphology occurred in 34 (39%) ICM patients and 33 (57%) of NICM patients, p=0.03. In addition, RVOT appearing PVC's were significantly more frequent in NICM patients (19 (33%) vs. 11 (13%) in ICM patients, p=0.003). There was no difference in the number of PVC's that appeared to originate from the LVOT [ICM vs. NICM, 15 (17%) vs. 9 (16%), p=NS] or from the sinus of Valsalva [ICM vs. NICM 9 (10%) vs. 8 (14%), p=NS]. Non-outflow tract appearing PVC's were significantly more common in patients with ICM when compared to patients with NICM, 53 (60%) vs. 22 (38%), p=0.008.

Conclusions:
In 15% of patients undergoing CRT implantation, >5000 PVCs were observed. While there was no difference in the burden of PVC between ICM and NICM patients, there were significant differences in morphology (and thus site of origin) of PVC's in the 2 groups of patients. These data may have implications, especially in patients in whom catheter ablation is necessary to eliminate PVC's in order to maximize CRT.